JP7581670B2 - Conductive member, manufacturing method thereof, and semiconductor device - Google Patents

Description

The present invention relates to a conductive member, a manufacturing method thereof, and a semiconductor device.

In recent years, with the increasing performance and functionality of electronic components, semiconductor packages of various configurations have been proposed. For example, a semiconductor package is known in which a semiconductor chip (semiconductor element) is bonded to a support member for mounting the semiconductor chip, and an adhesive is used for the bonding.

In the field of semiconductor packaging, attention has been focused on flip-chip mounting methods in which semiconductor chips are connected to each other and/or a semiconductor chip is connected to a support member for mounting the semiconductor chip via multiple conductive bumps. In flip-chip mounting methods, stress based on the difference in thermal expansion coefficients of the respective connected members can cause abnormalities in the connection between the substrate and the semiconductor chip via the conductive bumps. As a method for alleviating such stress, a method is known in which the conductive bumps are sealed by filling the gaps between the connected members with an underfill material such as resin (see, for example, Patent Document 1 below).

Furthermore, as the diameter and pitch of bumps applied to semiconductor chips become finer, alignment during connection becomes difficult, resulting in a significant drop in yield. To solve this problem, when connecting by heating or pressure, a process may be used in which, after aligning the substrate and semiconductor chip, the chip is temporarily fixed on the substrate at a temperature lower than the connection temperature, and then the temperature is raised to the connection temperature while thermocompression bonding is performed (see, for example, Non-Patent Document 1 below). Also under consideration is the suppression of misalignment by fitting bumps into vias formed using a photosensitive material (see, for example, Patent Document 2 below).

Patent No. 3999840 JP 2015-173196 A

Proceedings of 2009 Electronic Components and Technology Conference, 11-13 (2009).

In order to further improve the yield of semiconductor devices and the like, it is required that the conductive member that electrically connects the connected members be easily manufactured. Recently, connected members such as wearable devices have been widely used, and the connector that connects such connected members may be deformed by bending or the like. Therefore, it is required that the conductive member be able to maintain a sufficiently low connection resistance even after the connector is deformed.

The present disclosure aims to provide a conductive member that can be easily manufactured and in which the connection resistance value is unlikely to increase even when the member is deformed, and a method for manufacturing the same. The present disclosure also aims to provide a semiconductor device that uses the conductive member.

As a result of intensive research conducted by the inventors to achieve the above object, they discovered that a conductive member obtained by filling the through-holes of an organic insulating film having through-holes with a metal particle composition containing specific metal particles and sintering the resulting conductive member can have a sufficiently small connection resistance even after bending tests, which led to the completion of the present invention.

That is, one aspect of the present disclosure provides the following invention.
[1] A conductive member comprising an organic insulating film and a conductive portion penetrating the organic insulating film in a thickness direction, the conductive portion including a metal body having a porous structure, the metal body including a copper sintered body having a porous structure.
[2] The conductive member according to [1], wherein the metal body further contains solder distributed discretely.
[3] The conductive member according to [2], wherein the solder contains tin or a tin alloy.
[4] The conductive member according to [2], wherein the solder is In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or a Sn--Cu based alloy.
[5] The conductive member according to any one of [1] to [4], wherein the porosity of the metal body is 1 to 15 volume % based on the volume of the metal body.
[6] The conductive member according to any one of [1] to [5], wherein the conductive portion further comprises a cured resin or a semi-cured resin present in the pores of the metal body.
[7] The conductive member according to [6], wherein the content of the cured resin in the conductive portion is 80 volume % or more based on the total volume of the internal space of the pores of the metal body.
[8] The conductive member according to any one of [1] to [7], wherein the metal body is provided so as to penetrate the organic insulating film in a thickness direction, and the conductive portion includes a solder-containing portion provided so as to cover at least a portion of one end or both ends of the metal body.
[9] The conductive member according to [8], wherein the solder-containing portion contains tin or a tin alloy.
[10] The conductive member according to [8], wherein the solder-containing portion is an In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or Sn--Cu based alloy.
[11] The conductive member according to any one of [1] to [7], wherein the metal body is provided so as to penetrate the organic insulating film in a thickness direction, and the conductive portion includes an electroless plating film provided so as to cover at least a portion of one end or both ends of the metal body.
[12] The conductive member according to any one of [1] to [7], wherein the metal body is arranged to penetrate the organic insulating film in the thickness direction, and the conductive portion includes an electroless plating coating arranged to cover at least a portion of one end or both ends of the metal body, and a solder-containing portion arranged to cover the electroless plating coating.
[13] The conductive member according to [12], wherein the solder-containing portion contains tin or a tin alloy.
[14] The conductive member according to [12], wherein the solder-containing portion is an In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or Sn--Cu based alloy.
[15] The conductive member according to any one of [1] to [14], wherein the organic insulating film has a thickness of 1 to 50 μm.
[16] The conductive member according to any one of [1] to [15], wherein the organic insulating film includes a cured product of a photosensitive insulating film.

Further, other aspects of the present disclosure provide the following inventions.
[17] A semiconductor device having a connection structure in which a semiconductor chip and a support member for mounting a semiconductor chip are electrically connected to each other via the conductive member according to any one of [1] to [16], and/or a connection structure in which a plurality of semiconductor chips are electrically connected to each other via the conductive member according to any one of [1] to [16].

Further, other aspects of the present disclosure provide the following inventions.
[18] A method for producing a conductive member, comprising: a preparation step of preparing a base including an organic insulating film having through holes formed therein, the through holes communicating with both main surfaces thereof; and a conductor formation step of forming a conductor in the through holes, the conductor formation step including a metal body formation step of forming a metal body having a porous structure so as to fill at least the through holes, the metal body formation step including a filling step of filling the through holes of the base with a metal particle composition including copper particles, and a firing step of firing the metal particle composition to form the metal body.
[19] The method for producing a conductive member according to [18], wherein the metal particle composition further contains solder particles.
[20] The method for producing a conductive member according to [18] or [19], wherein the metal particle composition does not contain a curable resin component or contains a curable resin component in an amount of 4 mass% or less based on the total amount of the composition.
[21] The conductor forming step includes a resin impregnation step of impregnating the metal body with a curable resin composition,
The method for producing a conductive member according to any one of [18] to [20], further comprising a resin curing step of curing the curable resin composition impregnated into the metal body.
[22] The method for producing a conductive member according to any one of [18] to [21], further comprising a conductor removing step of removing at least a portion of the conductor formed on the main surface of the base.

Further, other aspects of the present disclosure provide the following inventions.
[23] A method for manufacturing a conductive member, comprising: a preparation step of preparing an organic insulating film having through holes connecting to both main surfaces; and a conductor formation step of forming a conductor in the through hole, wherein the conductor formation step comprises a metal body formation step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion formation step of forming a second metal portion covering at least a portion of one or both ends of the metal body, wherein the metal body formation step comprises a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form a metal body, and the second metal-containing portion formation step comprises a step of immersing the organic insulating film on which the metal body has been formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the metal body has been formed and heating the solder composition.
[24] A method for producing a conductive member, comprising: a preparation step of preparing an organic insulating film having through holes communicating with both main surfaces thereof; and a conductor formation step of forming a conductor in the through hole, wherein the conductor formation step comprises a metal body formation step of forming a metal body having a porous structure in the through hole; and a second metal-containing portion formation step of forming a second metal portion covering at least a portion of one or both ends of the metal body, wherein the metal body formation step comprises a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles; and a firing step of firing the metal particle composition to form a metal body, and the second metal-containing portion formation step comprises an electroless plating step of forming an electroless plating film so as to cover at least a portion of one or both ends of the metal body, and a step of immersing the organic insulating film on which the electroless plating film has been formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the electroless plating film has been formed and heating the solder composition.
[25] The method for producing a conductive member according to [23] or [24], wherein the conductor forming step includes, between the metal body forming step and the second metal-containing portion forming step, a resin impregnation step of impregnating the metal body with a curable resin composition, and a resin curing step of curing the curable resin composition impregnated into the metal body.
[26] A method for producing a conductive member, comprising: a preparation step of preparing an organic insulating film having through holes communicating with both main surfaces thereof; and a conductor formation step of forming a conductor in the through hole, wherein the conductor formation step comprises a metal body formation step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion formation step of forming a second metal portion covering at least a portion of one or both ends of the metal body, wherein the metal body formation step comprises a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form a metal body, and the second metal-containing portion formation step comprises a step of applying a solder paste containing solder particles and a curable resin composition onto one or both main surfaces of the organic insulating film on which the metal body has been formed, and a step of heating the applied solder paste.
[27] The method for producing a conductive member according to any one of [23] to [26], wherein the preparation step comprises exposing and developing a photosensitive insulating film to produce the organic insulating film.
[28] The method for producing a conductive member according to any one of [23] to [27], wherein the metal particle composition further contains solder particles.

According to the present disclosure, it is possible to provide a conductive member and a method for manufacturing the same that can be easily manufactured and that has a connection resistance value that is not likely to increase even after a bending test. Such a conductive member can be used as an anisotropic conductive member or a base having a through electrode. Furthermore, according to the present disclosure, it is possible to provide a semiconductor device using such a conductive member. Such a semiconductor device can be one in which the occurrence of cracks in the conductive portion when a semiconductor chip arranged on at least one surface of the conductive member is pressure-bonded can be more highly suppressed.

In addition, according to one aspect of the present disclosure, it is possible to provide a conductive member and a manufacturing method thereof that have sufficient conductivity, are unlikely to increase in connection resistance even after bending tests, and are unlikely to increase in resistance even when subjected to temperature changes, and to provide a semiconductor device using such a conductive member.

FIG. 2 is a schematic diagram illustrating an embodiment of a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating a method for manufacturing a conductive member. 5A to 5C are schematic diagrams illustrating another embodiment of a conductive member and a method for manufacturing the same. 5A and 5B are schematic diagrams illustrating another embodiment of a conductive member. 5A to 5C are schematic diagrams illustrating another embodiment of a conductive member and a method for manufacturing the same. 5A to 5C are schematic diagrams illustrating another embodiment of a conductive member and a method for manufacturing the same. 5A to 5C are schematic diagrams illustrating another embodiment of a conductive member and a method for manufacturing the same. 5A to 5C are schematic diagrams for explaining the manufacture of a conductive member. 1A to 1C are schematic diagrams illustrating a method for manufacturing a semiconductor device. 1A to 1C are schematic diagrams illustrating the fabrication of an evaluation substrate.

Below, the embodiments for implementing the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited to the following embodiments. In the drawings, the same or equivalent parts are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships such as up, down, left, right, etc. are based on the positional relationships shown in the drawings, and the dimensional ratios of the drawings are not limited to the ratios shown.

<Conductive member>
The conductive member according to the present embodiment includes an organic insulating film and a conductive portion penetrating the organic insulating film in a thickness direction, the conductive portion including a metal body having a porous structure, and the metal body including a copper sintered body having a porous structure. The conductive portion may be disposed (e.g., filled) in a through via formed in the organic insulating film, or may be disposed in the through via and on a part of a main surface of the organic insulating film.

"Penetrated" means that the conductive portion is exposed on both sides of the organic insulating film. "Insulated" means that the volume resistivity is 1.0× ¹⁰ Ω·cm or more. The volume resistivity is a value calculated from the sheet resistance measured with a four-point needle sheet resistance meter and the film thickness measured with a non-contact surface/layer cross-sectional shape measurement system (VertScan, Ryoka Systems Co., Ltd.).

The method of using the conductive member is not particularly limited, but it can be used as an electrode layer, wiring layer, power supply layer, electromagnetic wave shielding layer, heat dissipation layer formation, inter-electrode connection material, etc. In addition, the conductive member may be an anisotropic conductive member, and may be applied to a substrate having a through electrode.

Figure 1 is a cross-sectional view showing a schematic diagram of one embodiment of a conductive member. The conductive member 10 shown in Figure 1 includes an organic insulating film 1 and a plurality of conductive portions 5 penetrating the organic insulating film 1 in the thickness direction. Each of the plurality of conductive portions 5 is disposed at a distance from one another in a direction perpendicular to the thickness direction of the organic insulating film 1. The plurality of conductive portions 5 may be arranged regularly or irregularly in the direction perpendicular to the thickness direction of the organic insulating film 1. The conductive member 10 can be used as an anisotropic conductive member.

The organic insulating film may contain a photosensitive resin composition and/or a cured product thereof. The organic insulating film may be a photosensitive insulating film containing a photosensitive resin composition, or may contain a cured product of the photosensitive insulating film. From the viewpoint of reducing the via diameter and the conductive member, it is preferable that the organic insulating film contains a cured product of the photosensitive insulating film. The photosensitive insulating film can be formed using a photosensitive resin composition. By using such a photosensitive insulating film, it is possible to easily form an organic insulating film having a through via that is high-definition and has a smooth sidewall. In addition, it is preferable that the photosensitive insulating film is a negative photosensitive insulating film from the viewpoint of excellent mechanical properties and heat resistance.

From the viewpoints of excellent heat resistance and ease of handling during film formation, the photosensitive resin composition is preferably a negative photosensitive resin composition. In addition, examples of photosensitive resin compositions (photocurable resin compositions) include compositions containing a photoacid generator or a photoradical initiator, but from the viewpoint of easily obtaining fine patterns, compositions containing a photoacid generator are preferred. From the above viewpoints, the photosensitive resin composition is preferably a negative photosensitive resin composition containing a photoacid generator.

The photoacid generator is not particularly limited as long as it is a compound that generates an acid when irradiated with light, but for example, it is preferable to use an onium salt compound or a sulfonimide compound from the viewpoint of efficient acid generation. The photoacid generator can be used alone or in combination of two or more kinds.

Specific examples of onium salt compounds include iodonium salts and sulfonium salts. Specific examples of onium salt compounds include diaryliodonium salts such as diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, and diphenyliodonium tetrafluoroborate; triarylsulfonium salts such as triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, and triphenylsulfonium hexafluoroantimonate; 4-t-butylphenyl-diphenylsulfonium p-toluenesulfonate; and 4,7-di-n-butoxynaphthyltetrahydrothiophenium trifluoromethanesulfonate.

Specific examples of sulfonimide compounds include N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(trifluoromethylsulfonyloxy)naphthalimide, N-(p-toluenesulfonyloxy)-1,8-naphthalimide, and N-(10-camphorsulfonyloxy)-1,8-naphthalimide.

As the photoacid generator, a compound having a trifluoromethanesulfonate group, a hexafluoroantimonate group, a hexafluorophosphate group, or a tetrafluoroborate group is preferably used from the viewpoint of excellent resolution.

The photosensitive resin composition is preferably soluble in a 2.38% by mass aqueous solution of tetramethylammonium, and preferably contains a compound having a phenolic hydroxyl group from the viewpoint of excellent resolution, storage stability, and insulation reliability. Examples of compounds having a phenolic hydroxyl group include phenol/formaldehyde condensation novolac resin, cresol/formaldehyde condensation novolac resin, phenol-naphthol/formaldehyde condensation novolac resin, polyhydroxystyrene and its polymer, phenol-xylylene glycol condensation resin, cresol-xylylene glycol condensation resin, and phenol-dicyclopentadiene condensation resin. Here, "soluble" means that the compound dissolves to a degree of 10% by mass or more when immersed in a 2.38% by mass aqueous solution of tetramethylammonium at 25°C for 1 minute. The compound having a phenolic hydroxyl group can be used alone or in combination of two or more.

The photosensitive resin composition preferably contains a thermosetting resin. Examples of thermosetting resins include acrylate resins, epoxy resins, cyanate ester resins, maleimide resins, allylnadimide resins, phenolic resins, urea resins, melamine resins, alkyd resins, unsaturated polyester resins, diallyl phthalate resins, silicone resins, resorcinol formaldehyde resins, triallyl cyanurate resins, polyisocyanate resins, resins containing tris(2-hydroxyethyl)isocyanurate, resins containing triallyl trimellitate, and thermosetting resins synthesized from cyclopentadiene. From the viewpoint of excellent resolution, insulation reliability, and adhesion to metals, it is preferable that the thermosetting resin is a compound having any of a methylol group, an alkoxyalkyl group, and a glycidyl group. The thermosetting resins can be used alone or in combination of two or more types.

From the viewpoint of achieving excellent resolution, storage stability, and insulation reliability, the photosensitive resin composition preferably contains (A) a photoacid generator, (B) a compound having a phenolic hydroxyl group (hereinafter sometimes referred to as "component (B)"), and (C) a thermosetting resin.

The photosensitive resin composition may contain an adhesion aid. Examples of the adhesion aid that may be used include a silane coupling agent, a triazole compound, and a tetrazole compound.

As the silane coupling agent, a compound having a nitrogen atom is preferably used from the viewpoint of improving adhesion with the conductive part. Specific examples of the silane coupling agent include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, and 3-isocyanatopropyltriethoxysilane. The amount of the silane coupling agent used is preferably 0.1 to 20 parts by mass per 100 parts by mass of component (B) from the viewpoint of excellent effects of addition, heat resistance, cost, and the like.

Examples of triazole compounds include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and 2,2'-methylenebis[6-(2H-benzotriazol-2-yl]-4-tert-octylphenol]. 1, 6-(2-benzotriazolyl)-4-tert-octyl-6'-tert-butyl-4'-methyl-2,2'-methylenebisphenol, 1,2,3-benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, carboxybenzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl)methylbenzotriazole, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, etc.

Tetrazole compounds include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 1-methyl-5-ethyl-1H-tetrazole, 1-methyl-5-mercapto-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 1-(2-dimethylaminoethyl)-5-mercapto-1H-tetrazole, 2-methoxy-5-(5-trifluoromethyl-1H-tetrazol-1-yl)-benzaldehyde, 4,5-di(5-tetrazolyl)-[1,2,3]triazole, 1-methyl-5-benzoyl-1H-tetrazole, and the like.

The amount of each of the triazole compound and the tetrazole compound used is preferably 0.1 to 20 parts by mass per 100 parts by mass of component (B) from the viewpoints of excellent effects of addition, heat resistance, cost, etc.

Each of these silane coupling agents, triazole compounds, and tetrazole compounds can be used alone or in combination of two or more.

The photosensitive resin composition may also contain an ion trapping agent. The ion trapping agent adsorbs ionic impurities, improving the insulation reliability during moisture absorption. There are no particular limitations on the ion trapping agent, and examples include compounds known as copper damage inhibitors for preventing copper from ionizing and dissolving, such as triazine thiol compounds and phenol-based reducing agents, and inorganic compounds such as powdered bismuth-, antimony-, magnesium-, aluminum-, zirconium-, calcium-, titanium-, and tin-based compounds, as well as mixtures of these.

Specific examples of ion scavengers include, but are not limited to, inorganic ion scavengers manufactured by Toagosei Co., Ltd. under the trade names: IXE-300 (antimony-based), IXE-500 (bismuth-based), IXE-600 (antimony and bismuth mixed system), IXE-700 (magnesium and aluminum mixed system), IXE-800 (zirconium-based), and IXE-1100 (calcium-based). The ion scavengers can be used alone or in combination of two or more. The amount of the ion scavengers used is preferably 0.01 to 10 parts by mass per 100 parts by mass of component (B) from the viewpoints of excellent effects of addition, heat resistance, cost, etc.

The photosensitive resin composition may contain a curing agent, a curing accelerator, a filler, etc. as appropriate.

The photosensitive resin composition may contain a solvent. There are no particular limitations on the solvent used, and examples of the solvent include ethyl lactate, N-methylpyrrolidinone, cyclohexanone, γ-butyrolactone, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether.

The thickness of the organic insulating film is preferably 1 to 100 μm from the viewpoint of excellent handleability, more preferably 50 μm or less from the viewpoint of thinning the semiconductor device, and even more preferably 20 μm or less from the viewpoint of obtaining finer conductive parts. The thickness of the organic insulating film is preferably 2 μm or more from the viewpoint of excellent handleability of the film. From these viewpoints, the thickness of the organic insulating film is preferably 2 to 50 μm.

The conductive portion 5 includes a metal body having a porous structure, and the metal body contains a copper sintered body having a porous structure. The metal body having a porous structure can be formed by a metal body forming process described later using a metal particle composition described later.

The copper sintered body contained in the metal body may have a copper element ratio of 95% by mass or more, 97% by mass or more, 98% by mass or more, or 100% by mass, among the constituent elements excluding light elements. If the copper element ratio in the copper sintered body is within the above range, the formation of intermetallic compounds or the precipitation of different elements at the metallic copper crystal boundaries can be suppressed, the properties of the metallic copper constituting the copper sintered body are likely to be strengthened, and even better connection reliability is likely to be obtained.

The porosity of the metal body is preferably 1 to 15 volume % based on the volume of the metal body. From the viewpoint of reducing the volume resistivity of the metal body, the porosity of the metal body filled in the through holes (the proportion of voids contained in the metal body) may be 15 volume % or less, 14 volume % or less, 12 volume % or less, or 9 volume % or less based on the total volume (including voids) of the metal body. In addition, from the viewpoint of alleviating the stress applied to the copper sintered body and suppressing warping of the organic insulating film, the porosity of the metal body may be 1 volume % or more, 3 volume % or more, or 5 volume % or more.

In the conductive member of this embodiment, the metal body may further contain solder that is distributed discretely, in other words, present in a scattered manner. The solder preferably contains tin or a tin alloy, and more preferably is an In-Sn, In-Sn-Ag, Sn-Bi, Sn-Bi-Ag, Sn-Ag-Cu, or Sn-Cu alloy. Such a conductive member may be resistant to an increase in connection resistance even when subjected to large deformation such as bending.

The amount of solder contained in the metal body may be 3 parts by mass or more, 10 parts by mass or more, or 10 parts by mass or more, relative to 100 parts by mass of the copper sintered body contained in the metal body, from the viewpoint of suppressing cracks in the metal body, and may be 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less, from the viewpoint of reducing the volume resistivity of the metal body.

In the conductive member of this embodiment, the conductive portion may further comprise a cured resin or semi-cured resin present in the pores of the metal body. In this case, the content of the cured resin in the conductive portion may be 80 volume % or more, 90 volume % or more, or 95 volume % or more based on the total volume of the internal space of the pores of the metal body. Such a conductive member may be resistant to an increase in connection resistance even when subjected to large deformation such as bending.

The resin cured product and the resin semi-cured product can be formed from the curable resin composition described below.

In the conductive member of this embodiment, the metal body is arranged to penetrate the organic insulating film in the thickness direction, and the conductive portion may include a solder-containing portion arranged to cover at least a portion of one end or both ends of the metal body.

The solder-containing portion preferably contains tin or a tin alloy, and more preferably is an In-Sn, In-Sn-Ag, Sn-Bi, Sn-Bi-Ag, Sn-Ag-Cu, or Sn-Cu based alloy.

In the conductive member of this embodiment, the metal body is arranged to penetrate the organic insulating film in the thickness direction, and the conductive portion may include an electroless plating film arranged to cover at least a portion of one end or both ends of the metal body.

The electroless plating film may be an electroless nickel plating film, an electroless gold plating film such as displacement gold plating, an electroless nickel/gold plating film in which electroless gold plating is applied to the surface of an electroless nickel plating film, or an electroless nickel/palladium/gold plating film in which electroless palladium plating and electroless gold plating are applied to the surface of an electroless nickel plating film. The thickness of the electroless plating film may be 0.1 μm to 5 μm.

In addition, the conductive member of this embodiment may be such that the metal body is provided so as to penetrate the organic insulating film in the thickness direction, and the conductive portion may include an electroless plating film provided so as to cover at least a portion of one end or both ends of the metal body, and a solder-containing portion provided so as to cover the electroless plating film. In this case, the electroless plating film and the solder-containing portion may be provided in the same manner as described above.

The conductive member of this embodiment may also have a resin layer provided on one or both main surfaces of the organic insulating film.

The resin layer may contain a curable resin composition or a semi-cured product thereof (semi-cured resin product).

The resin layer may be provided so as to cover the conductor, or so as to expose a portion of the coated conductor. The thickness of the resin layer may be 1 μm to 20 μm.

<Method of manufacturing conductive member>
The method for manufacturing a conductive member according to this embodiment includes a preparation step of preparing a base including an organic insulating film having through holes formed therein, the through holes communicating with both main surfaces, and a conductor formation step of forming a conductor in the through hole, the conductor formation step including a metal body formation step of forming a metal body having a porous structure so as to fill at least the through hole, the metal body formation step including a filling step of filling the through holes of the base with a metal particle composition including copper particles, and a firing step of firing the metal particle composition to form a metal body.

Figures 2 to 7 are schematic diagrams showing an example of a method for manufacturing a conductive member according to this embodiment, and show an example of manufacturing a substrate having a through electrode as a conductive member. In this manufacturing method, the conductor formation process may further include a resin impregnation process for impregnating a metal body with a curable resin composition, and a resin curing process for curing the curable resin composition impregnated in the metal body.

<Substrate Preparation Step>
2(a), it is possible to prepare an organic insulating film 1 having a through hole 30 formed therein, and a metal coating 2 formed on the wall surface of the through hole and on the surface of the organic insulating film 1. The through hole 30 communicates with both main surfaces of the organic insulating film 40 having a metal coating formed thereon.

The organic insulating film 1 can be produced, for example, by exposing and developing a photosensitive insulating film containing the above-mentioned photosensitive resin composition using a known method.

The upper limit of the diameter of the through hole 30 may be 80 μm or less, 60 μm or less, or 40 μm or less from the viewpoint of increasing the density of the resulting semiconductor device, and the lower limit of the diameter of the through hole 30 is not particularly limited, but may be 2 μm or more, or 5 μm or more.

The number of through holes 30 provided in the metal coated organic insulating film 40 may be 100 or more, or 300 or more per 1 cm ² of the main surface of the substrate, from the viewpoint of increasing the density of the resulting semiconductor device.

The metal coating 2 may be provided on both main surfaces of the organic insulating film 1 and on the wall surface of the through hole 30, or on at least one main surface of the organic insulating film 1 and on the wall surface of the through hole 30, or may be provided only on the wall surface of the through hole 30, or may not be provided at all. In the embodiment shown in FIG. 2(a), the organic insulating film 40 with the metal coating formed thereon has the metal coating 2 on both main surfaces of the organic insulating film 1 and on the wall surface of the through hole 30.

Examples of the metal coating 2 include titanium, nickel, chromium, copper, aluminum, palladium, platinum, and gold. From the viewpoint of adhesion, the metal coating 2 is preferably a coating in which titanium, nickel, and copper are layered in this order. Adhesion is improved by oxidizing the surface of the organic insulating film 1 to silicon oxide and forming a titanium layer on the silicon oxide. In addition, by providing a nickel layer on the titanium layer and then a copper layer on top of that, it is possible to suppress the diffusion of copper into the organic insulating film 1 compared to the case where a copper layer is directly provided on the titanium layer. Furthermore, by providing a copper layer on the surface, adhesion is improved between the metal body formed in the metal body forming process described below and the organic insulating film 40 on which the metal coating has been formed.

<Metal body forming process>
In the method shown in Figures 2 to 7, the metal body forming step includes a filling step of filling the through holes of the base with a metal particle composition containing copper particles and solder particles, and a firing step of firing the metal particle composition to form a metal body, and these steps form a metal body containing a copper sintered body and solder having a porous structure so as to fill at least the through holes. In the metal body forming step, the metal body may be formed so as to cover at least a part of the main surface of the metal coating-formed organic insulating film 40. In this case, a conductor is formed to fill the through holes of the metal coating-formed organic insulating film 40, and a conductor can also be provided on the main surface of the metal coating-formed organic insulating film 40. The conductor provided on the main surface of the metal coating-formed organic insulating film 40 can form wiring and an organic insulating film through electrode.

In the methods shown in Figures 2 to 7, a layer of metal particle composition is provided on both main surfaces of the substrate in the filling step, but a layer of metal particle composition may be provided on both main surfaces of the substrate after the filling step.

As the metal body forming process, for example, as shown in FIG. 2(b), a metal particle composition 3 containing copper particles and solder particles is applied to a metal-coated organic insulating film 40, and the metal particle composition 3 is filled into the through-holes 30, and layers of the metal particle composition 3 are also provided on both main surfaces of the metal-coated organic insulating film 40. Details of the metal particle composition 3 will be described later.

Methods for applying the metal particle composition to a substrate include, for example, screen printing, transfer printing, offset printing, jet printing, and application using a dispenser, jet dispenser, needle dispenser, comma coater, slit coater, die coater, gravure coater, slit coat, letterpress printing, intaglio printing, gravure printing, stencil printing, soft lithography, bar coat, applicator, particle deposition method, spray coater, spin coater, dip coater, etc.

When the metal particle composition is also applied onto the main surface of the substrate, the thickness of the metal particle composition layer may be 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more, and may be 300 μm or less, 250 μm or less, 200 μm or less, 150 μm or less, 120 μm or less, 100 μm or less, 80 μm or less, or 50 μm or less.

The metal particle composition may be dried as appropriate from the viewpoint of preventing the copper particles, or the copper particles and the solder particles, from flowing during sintering of the metal particle composition, and preventing the occurrence of voids in the copper sintered body contained in the metal body. When drying the metal particle composition, the atmosphere during drying may be an oxygen-free atmosphere such as nitrogen and a rare gas, or a reducing atmosphere such as hydrogen and formic acid.

The drying method may be drying at room temperature, drying by heating, or drying under reduced pressure. For example, a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far-infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, a heater heating device, a steam heating furnace, a hot plate press device, etc. can be used for drying by heating or drying under reduced pressure. The drying temperature and time may be appropriately adjusted according to the type and amount of the dispersion medium used. The drying temperature may be, for example, 50°C or higher and 180°C or lower. The drying time may be, for example, 1 minute or more and 120 minutes or less.

After the filling step, the metal particle composition 3 is fired to sinter the copper particles contained in the metal particle composition 3. In this way, as shown in (c1) of FIG. 3, a metal body-filled organic insulating film 50 is obtained, which includes a copper sintered body having a porous structure and solder, and in which a metal body 5 having voids (pores) 4 fills the through holes 30. In this embodiment, a metal body-filled organic insulating film 50 is obtained in which a metal body 5 is also provided on both main surfaces of the metal coating-formed organic insulating film 40. (c2) of FIG. 3 is a schematic diagram showing the configuration of the metal body. The metal body includes a copper sintered body 12 having a porous structure, solder 14 that is distributed discretely in the copper sintered body 12, in other words, exists in a scattered manner, and voids 4. The metal body can include, as voids 4, the pores of the copper sintered body 12, voids present inside the solder 14, and voids present between the copper sintered body 12 and the solder 14. When using a metal particle composition containing copper particles, a metal body can be formed that contains a copper sintered body having a porous structure, and the metal body can have a porous structure derived from the copper sintered body.

The firing can be carried out by a heat treatment. For the heat treatment, a heating means such as a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far-infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, a heater heating device, or a steam heating furnace can be used.

The atmosphere during firing may be an oxygen-free atmosphere from the viewpoint of suppressing oxidation of the copper sintered body, or a reducing atmosphere from the viewpoint of removing the surface oxide of the copper particles in the metal particle composition 3. Examples of the oxygen-free atmosphere include the introduction of an oxygen-free gas such as nitrogen or a rare gas, or under a vacuum. Examples of the reducing atmosphere include pure hydrogen gas, a mixed gas of hydrogen and nitrogen represented by forming gas, nitrogen containing formic acid gas, a mixed gas of hydrogen and a rare gas, and a rare gas containing formic acid gas. When the metal particle composition 3 is sintered by heating without pressurization, it is preferably in pure hydrogen gas or a mixed gas of hydrogen and nitrogen represented by forming gas, and preferably in pure hydrogen gas. By heating in pure hydrogen gas, it is possible to lower the sintering temperature of the copper particles. When pure hydrogen gas is used, even if the thickness of the organic insulating film is as thick as 100 μm and the diameter of the through hole 30 is as small as 10 μm, the gas reaches the center of the through hole 30, making it easy to obtain the metal body 5 containing the copper sintered body.

The maximum temperature reached during the heat treatment may be 150°C or higher, and may be 350°C or lower, 300°C or lower, or 260°C or lower, from the viewpoint of reducing thermal damage to each component and improving yield. If the maximum temperature reached is 150°C or higher, sintering tends to proceed sufficiently when the maximum temperature is held for 60 minutes or less. From the viewpoint of volatilizing all the dispersion medium and improving yield, the maximum temperature held for may be 1 minute or more, and may be 60 minutes or less, 40 minutes or less, or 30 minutes or less.

The metal particle composition may be sintered under pressure. In this case, in an atmosphere containing pure hydrogen gas, the pressure may be 0.05 MPa or more, 0.1 MPa or more, or 0.3 MPa or more, and 20 MPa or less, 15 MPa or less, or 10 MPa or less. In an atmosphere containing nitrogen gas, the pressure may be 1 MPa or more, or 3 MPa or more, and 20 MPa or less, 15 MPa or less, or 10 MPa or less.

When pure hydrogen gas is used, the pressure is set to 0.05 MPa or more, and when nitrogen gas is used, the pressure is set to 1 MPa or more, which makes it easier to suppress the generation of voids in the metal body 5 formed in the center of the through hole 30, and makes it easier to obtain a metal body with good conductivity. In addition, when the organic insulating film 1 has a metal coating 2, the pressure is set to the above-mentioned lower limit value or more, and when the organic insulating film 1 has a metal coating 2, the bonding strength between the metal coating 2 and the metal body 5 is easily improved. Furthermore, as shown in FIG. 4, when the metal-coated organic insulating film 40 provided with a metal particle composition layer is pressed by sandwiching it from above and below with the pressing tool A, the pressure applied to the pressing tool A is set to the above-mentioned lower limit value or more, which makes it easier to smooth the surface of the metal body formed on the main surface of the metal-coated organic insulating film 40. If the surface of the metal body is smooth, there is an advantage that fine wiring is easily formed when wiring is formed by etching or the like in a later process. The pressing tool A is not particularly limited, but may be a commercially available one, and may also be prepared using a metal member having a flat portion. For example, a pressure jig having two or more of the above-mentioned metal members can pressurize the metal-coated organic insulating film by sandwiching the metal-coated organic insulating film between the metal members arranged so that the flat portions face each other. Pressure jig A may have a mechanism for adjusting the pressure applied to the metal-coated organic insulating film. A spring or the like can be used as the pressure adjustment means.

If the pressure is 20 MPa or less, the warping of the organic insulating film is easily suppressed. The inventors speculate that the reason for obtaining such an effect is as follows. First, when the pressure is increased, the sintered density of the copper particles contained in the metal particle composition (particularly the density of the side in contact with the pressure jig A) increases, and the thermal expansion coefficient of the formed copper sintered body is thought to approach the thermal expansion coefficient of general copper at 25°C of 16.5 μm/(m·K). On the other hand, the thermal expansion coefficient of an organic insulating film, for example, polyethylene terephthalate, at 25°C is 65 μm/(m·K). Therefore, as the density of the copper sintered body increases, the difference in the thermal expansion coefficient between the copper sintered body and the organic insulating film increases, and it is thought that warping is more likely to occur. In this embodiment, it is believed that by setting the pressure to 20 MPa or less, the increase in the density of the copper sintered body is moderately suppressed, and as a result, the difference in the thermal expansion coefficient between the copper sintered body and the organic insulating film becomes smaller, and warping is suppressed.

In addition, if the pressure applied during firing is within the above range, no special pressure device is required, and the yield is not compromised, and voids can be reduced and the bonding strength and connection reliability can be further improved. Methods for applying pressure to an organic insulating film filled with a metal particle composition include, for example, a method of placing a weight on the film, a method of applying pressure using a pressure device, and a method of applying pressure using a fixed jig for applying pressure.

From the viewpoint of reducing the volume resistivity of the metal body, the porosity (proportion of voids contained in the metal body) of the metal body formed on the main surface of the organic insulating film may be 15 volume % or less, 14 volume % or less, 12 volume % or less, or 9 volume % or less based on the total volume of the metal body (including voids). In addition, from the viewpoint of suppressing cracking and warping of the organic insulating film, the porosity of the metal body may be 1 volume % or more, 3 volume % or more, or 5 volume % or more.

By having the metal body formed on the main surface of the organic insulating film have the above-mentioned porous structure, it is possible to lower the thermal expansion coefficient, reduce the difference in thermal expansion coefficient with the organic insulating film, and suppress warping of the organic insulating film.

From the viewpoint of reducing the volume resistivity of the metal body, the porosity of the metal body filled in the through holes (the proportion of voids contained in the metal body) may be 15 vol.% or less, 14 vol.% or less, 12 vol.% or less, or 9 vol.% or less based on the total volume of the metal body (including voids). In addition, from the viewpoint of alleviating the stress applied to the copper sintered body and suppressing warping of the organic insulating film, the porosity of the metal body may be 1 vol.% or more, 3 vol.% or more, or 5 vol.% or more.

By having the metal body filled in the through holes have the above-mentioned porous structure, the stress applied to the metal body can be alleviated, thereby suppressing warping of the organic insulating film.

The porosity of the metal body is calculated by the following procedure.
(i) A cross section of a metal body of a metal body-filled organic insulating film (a cut surface in the thickness direction of the film) is exposed by a focused ion beam.
(ii) A cross-sectional image (within a range of 10 μm in the thickness direction of the substrate and 10 μm in a direction perpendicular to the thickness direction of the substrate) of the exposed cross section is photographed using a scanning electron microscope.
(iii) The cross-sectional image obtained is binarized so that the metal portion and the porous portion are separated.
(iv) From the binarized cross-sectional image, the ratio of the area of the porous portion to the total area of the cross-section of the metal body is determined as the porosity of the metal body.
When calculating the porosity of the metal body filled in the through hole, in the above (i), a cross section of the central part of the metal body filled in the through hole is exposed. When calculating the porosity of the central part of the metal body filled in the through hole, a range of ±5 μm in the thickness direction of the substrate and ±5 μm in the direction perpendicular to the thickness direction of the substrate is observed from the central part of the metal body filled in the through hole. When calculating the porosity of the metal body formed on the main surface of the metal body-filled organic insulating film, in the above (i), a cross section of the metal body on the main surface is exposed. When calculating the porosity of the metal body formed on the main surface of the metal body-filled organic insulating film, a region up to 5 μm from the surface of the metal body formed on the main surface is observed.
When calculating the porosity of the metal body used to calculate the filling rate of the cured resin in the conductor described below, the observation points of the metal body can be appropriately set to be the same as the observation points of the conductor.

In addition, if the pressure applied during firing is within the above range, no special pressure device is required, and the yield is not compromised, and voids can be reduced and the bonding strength and connection reliability can be further improved. Methods for applying pressure to an organic insulating film filled with a metal particle composition include, for example, a method of placing a weight on the film, a method of applying pressure using a pressure device, and a method of applying pressure using a fixture for applying pressure.

The copper sintered body contained in the metal body may have a copper element ratio of 95% by mass or more, 97% by mass or more, 98% by mass or more, or 100% by mass, among the constituent elements excluding light elements. If the copper element ratio in the copper sintered body is within the above range, the formation of intermetallic compounds or the precipitation of different elements at the metallic copper crystal boundaries can be suppressed, the properties of the metallic copper constituting the copper sintered body are likely to be strengthened, and even better connection reliability is likely to be obtained.

The amount of solder contained in the metal body may be 3 parts by mass or more, 10 parts by mass or more, or 10 parts by mass or more, relative to 100 parts by mass of the copper sintered body contained in the metal body, from the viewpoint of suppressing cracks in the metal body, and may be 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less, from the viewpoint of reducing the volume resistivity of the metal body.

In the metal body forming process, the metal particle composition may be heated and fired without applying pressure. In this case, the porosity of the metal body formed on the main surface of the organic insulating film tends to be large, and the thermal expansion coefficient of the metal body is reduced, making it less likely for the organic insulating film to warp.

In this embodiment, the metal particle composition contains copper particles and solder particles, but a metal particle composition that does not contain solder particles and contains copper particles may also be used.

<Resin impregnation process>
In this step, for example, the metal body 5 can be impregnated with the curable resin composition by applying the curable resin composition to the metal body-filled organic insulating film 50 obtained through the metal body formation step. In this embodiment, the metal body 5 filling the through hole 30 and the metal body 5 formed on both main surfaces of the metal coated organic insulating film 40 are impregnated with the curable resin composition. It is preferable that the voids 4 of the metal body 5 are sufficiently filled with the impregnated curable resin composition.

The components constituting the curable resin composition include thermosetting compounds. Examples of the thermosetting compounds include oxetane compounds, epoxy compounds, episulfide compounds, (meth)acrylic compounds, phenol compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, silicone compounds, and polyimide compounds. Among them, epoxy compounds may be used because they further improve the curability and viscosity of the curable resin composition and improve the characteristics and insulation reliability when left at high temperatures.

The curable resin composition may further include a heat curing agent. Examples of heat curing agents include imidazole curing agents, amine curing agents, phenol curing agents, polythiol curing agents, acid anhydrides, thermal cationic initiators, and thermal radical generators. These may be used alone or in combination of two or more. Among these, imidazole curing agents, polythiol curing agents, and amine curing agents are preferred because they can be cured quickly at low temperatures. In addition, latent curing agents are preferred because they have high storage stability when mixed with a thermosetting compound and a heat curing agent. The latent curing agent is preferably a latent imidazole curing agent, a latent polythiol curing agent, or a latent amine curing agent. The heat curing agent may be coated with a polymeric substance such as a polyurethane resin or a polyester resin.

The imidazole curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct.

The polythiol curing agent is not particularly limited, and examples thereof include trimethylolpropane tris-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, and dipentaerythritol hexa-3-mercaptopropionate. The solubility parameter of the polythiol curing agent is preferably 9.5 or more, and more preferably 12 or less. The solubility parameter is calculated by the Fedors method. For example, the solubility parameter of trimethylolpropane tris-3-mercaptopropionate is 9.6, and the solubility parameter of dipentaerythritol hexa-3-mercaptopropionate is 11.4.

The above amine curing agent is not particularly limited, and examples thereof include hexamethylenediamine, octamethylenediamine, decamethylenediamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5.5]undecane, bis(4-aminocyclohexyl)methane, metaphenylenediamine, and diaminodiphenylsulfone.

The above-mentioned thermal cationic curing agents include iodonium cationic curing agents, oxonium cationic curing agents, and sulfonium cationic curing agents. The above-mentioned iodonium cationic curing agents include bis(4-tert-butylphenyl)iodonium hexafluorophosphate. The above-mentioned oxonium cationic curing agents include trimethyloxonium tetrafluoroborate. The above-mentioned sulfonium cationic curing agents include tri-p-tolylsulfonium hexafluorophosphate.

The thermal radical generator is not particularly limited, and examples thereof include azo compounds and organic peroxides. Examples of the azo compounds include azobisisobutyronitrile (AIBN). Examples of the organic peroxides include di-tert-butyl peroxide and methyl ethyl ketone peroxide.

Methods for applying the curable resin composition include screen printing, transfer printing, offset printing, jet printing, dispenser, jet dispenser, needle dispenser, comma coater, slit coater, die coater, gravure coater, slit coat, letterpress printing, intaglio printing, gravure printing, stencil printing, soft lithography, bar coat, applicator, particle deposition method, spray coater, spin coater, dip coater, etc.

The curable resin composition may be applied to one of the main surfaces of the metal body-filled organic insulating film 50, or may be applied to a portion of the main surface. When applying the resin composition to both sides of the metal body-filled organic insulating film 50, the resin composition may be applied to one of the main surfaces of the metal body-filled organic insulating film 50, the resin composition may be allowed to penetrate to the main surface side of the metal body-filled organic insulating film 50 to which the resin composition has not been applied, and then the resin composition may be applied to the main surface to which the resin composition has not been applied. This allows the resin composition to permeate the voids 4.

By leaving the metal body-filled organic insulating film 50 coated with the curable resin composition in a reduced pressure environment, the impregnation of the curable resin composition into the pores 4 of the metal body 5 can be improved.

In the resin impregnation step, it is preferable to impregnate the metal body with the cured resin composition so that the filling rate of the cured resin in the conductor formed through the resin curing step falls within the preferred range described below.

<Resin curing process>
In this step, as shown in (d1) of FIG. 5, the curable resin composition impregnated into the metal body 5 (the curable resin composition filled in the pores 4) is cured to form a conductor 35 including the metal body 5 in which the pores 4 are filled with the resin cured material 6, and a substrate 51 having an organic insulating film through electrode in which a through electrode is provided in the through hole 30 of the organic insulating film can be obtained. In the case of this embodiment, the conductor 35 including the metal body 5 in which the pores 4 are filled with the resin cured material 6 is also provided on both main surfaces of the organic insulating film 40 on which the metal coating has been formed. (d2) of FIG. 5 is a schematic diagram showing the configuration of the conductor. The conductor includes the copper sintered body 12, the solder 14, and the resin cured material 6 filled in the pores. The solder 14 may be distributed discretely in the conductor 35, in other words, scattered. The resin cured material 6 may be present in the pores of the copper sintered body 12, the voids present inside the solder 14, and the voids present between the copper sintered body 12 and the solder 14.

The curable resin composition can be cured by a heat treatment. For the heat treatment, a heating means such as a hot plate, a hot air dryer, a hot air heating furnace, a nitrogen dryer, an infrared dryer, an infrared heating furnace, a far-infrared heating furnace, a microwave heating device, a laser heating device, an electromagnetic heating device, a heater heating device, or a steam heating furnace can be used.

The atmosphere in the resin curing step may be an oxygen-free atmosphere from the viewpoint of suppressing oxidation of the metal body 5 (particularly the copper sintered body), or a reducing atmosphere from the viewpoint of removing surface oxides of the metal body 5 (particularly the copper sintered body). Examples of the oxygen-free atmosphere include the introduction of an oxygen-free gas such as nitrogen or a rare gas, or a vacuum. Examples of the reducing atmosphere include a pure hydrogen gas, a mixed gas of hydrogen and nitrogen such as forming gas, nitrogen containing formic acid gas, a mixed gas of hydrogen and a rare gas, and a rare gas containing formic acid gas.

The maximum temperature reached during the heat treatment in the resin curing process may be 150°C or higher, and may be 350°C or lower, 300°C or lower, or 260°C or lower, from the viewpoint of reducing thermal damage to each component and improving yield. If the maximum temperature reached is 150°C or higher, the curing of the resin composition tends to proceed sufficiently when the maximum temperature is held for 60 minutes or less.

The conductor 35 formed in the resin curing process (the conductor before the conductor removal process) may have a content (filling rate) of the cured resin 6 that satisfies the following conditions:

(Through-hole conductor)
(a) In a region (see (d1) in FIG. 5 ) that passes through central portion C of through hole 30 (the center of the hole length and the center of the hole diameter there) and extends from point S1, where line L1 extending in the thickness direction of the substrate intersects with the surface of conductor 35, to a depth of 10 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the internal space of the pores (voids) of the metal body.
(b) In the region 10 to 20 μm deep from point S1, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(c) In the region from point S1 to a depth of 20 to 30 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(d) Within a range of ±5 μm from the center C of the through hole 30 in the thickness direction of the substrate and in a direction perpendicular to the thickness direction of the substrate, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

(Conductors on the main surface of the substrate)
(e) In the region from the surface S2 of the conductor 35 formed on the main surface of the substrate to a depth of 5 μm (see (d1) in FIG. 5 ), the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(f) In the region from the surface S2 of the conductor 35 formed on the main surface of the substrate to a depth of 10 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(g) In a region 10 to 20 μm deep from the surface S2, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(h) In the region 20 to 30 μm deep from the surface S2, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

The filling rate of the cured resin 6 in the conductor 35 is calculated by the following procedure.
(i) A cross section of a conductor of a substrate (a cut surface in the thickness direction of the substrate) on which the conductor is provided is exposed by a focused ion beam.
(ii) A cross-sectional image (within a range of 10 μm in the thickness direction of the substrate and 10 μm in a direction perpendicular to the thickness direction of the substrate) of the exposed cross section is photographed using a scanning electron microscope.
(iii) The cross-sectional image obtained is binarized so that the metal and cured resin portions are separated from the porous portions not filled with the cured resin.
(iv) From the binarized cross-sectional image, the ratio of the area of the porous portion not filled with the cured resin to the total area of the cross-section of the conductor is calculated, and this is regarded as the porosity of the conductor.
(v) The filling rate of the cured resin in the conductor is calculated by substituting the porosity of the metal body before impregnation with the curable resin composition and the porosity of the conductor into the following formula (1).
Filling rate (%) of cured resin in conductor=[(B−A)/B]×100 Equation (1)
[In formula (1), A represents the porosity (%) of the conductor, and B represents the porosity (%) of the metal body.]
When calculating the porosity of the conductor filled in the through-hole, a cross section of the central part of the conductor in the through-hole is exposed in the above (i).When calculating the porosity of the conductor formed on the main surface of the metal coating-formed organic insulating film, a cross section of the conductor on the main surface is exposed in the above (i).

<Conductor Removal Process>
In this step, it is possible to remove at least a part of the conductor 35 formed on the main surface of the metal-coated organic insulating film 40. Methods for removing the conductor include chemical polishing, mechanical polishing, chemical-mechanical polishing, fly-cutting, plasma treatment, etc. Fly-cutting refers to cutting and flattening with a surface planer.

In this embodiment, from the viewpoint of being easily applicable using a general method, it is preferable that the removal means is one or more selected from the group consisting of etching, mechanical polishing, and chemical mechanical polishing.

The method for manufacturing a conductive member according to this embodiment includes a conductor removal process, which makes it easier to form wiring, for example, by making the surface of the conductor 35 formed on the main surface of the metal-coated organic insulating film 40 flat.

In this embodiment, the filling rate of the cured resin 6 in the conductor 35 after the conductor removal process may satisfy the following condition. The filling rate can be calculated in the same manner as above.

(Through-hole conductor)
(a) In a region extending from a point S3 passing through a central portion C of the through hole 30 (the center of the hole length and the center of the hole diameter D there) where a line L1 extending in the thickness direction of the substrate intersects with the surface of the conductor 35 to a depth of 10 μm (see FIG. 6(e)), the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the internal space of the pores (voids) of the metal body.
(b) In the region 10 to 20 μm deep from point S3, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(c) In the region from point S3 to a depth of 20 to 30 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(d) Within a range of ±5 μm from the center C of the through hole 30 in the thickness direction of the substrate and in a direction perpendicular to the thickness direction of the substrate, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

(Conductors on the main surface of the substrate)
(e) In a region from the surface S4 of the conductor 35 formed on the main surface of the substrate to a depth of 5 μm (see FIG. 6 (e)), the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the internal space of the porous (void) parts of the metal body.
(f) In the region from the surface S4 of the conductor 35 formed on the main surface of the substrate to a depth of 10 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(g) In the region 10 to 20 μm deep from the surface S4, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(h) In the region 20 to 30 μm deep from the surface S4, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

From the viewpoint of increasing the density of the resulting semiconductor device, the ratio L/D of the length L to the hole diameter D of the organic insulating film through electrode may be 1 or more, 5 or more, or 10 or more, and may be 15 or less, 10 or less, or 5 or less. The length L of the organic insulating film through electrode may be the thickness of the substrate having the organic insulating film through electrode. In this case, the ratio T/D of the thickness T of the substrate having the organic insulating film through electrode to the hole diameter D of the organic insulating film through electrode may be in the above range.

In the method for manufacturing the conductive member of this embodiment, the conductor is filled with a cured resin, but the resin impregnation process and the resin curing process described above may be omitted and the through electrode may be formed from the metal body.

The method for manufacturing a conductive member according to this embodiment may further include a wiring formation process. The wiring formation process may include a resist formation process, an etching process, and a resist removal process, which are described below.

<Resist Forming Process>
In the resist formation step, as shown in FIG. 6( f ), an etching resist 8 is formed on the conductor 35 formed on the main surface of the organic insulating film 40 on which the metal coating has been formed.

Methods for forming the etching resist 8 include, for example, silk screen printing resist ink, or laminating a negative photosensitive dry film for etching resist onto copper foil, placing a light-transmitting photomask on top of it in the shape of the wiring, exposing it to ultraviolet light, and removing the unexposed areas with a developer.

<Etching process>
7(g), the conductor 35 in the portion not covered with the etching resist 8 is removed by etching. In this embodiment, a portion of the metal coating 2 provided on each of the main surfaces of the organic insulating film 1 is removed by etching.

Examples of etching methods include those using chemical etching solutions typically used for wiring boards, such as a solution of cupric chloride and hydrochloric acid, a solution of ferric chloride, a solution of sulfuric acid and hydrogen peroxide, or an ammonium persulfate solution.

<Resist Removal Process>
In the resist removal step, the etching resist 8 formed on the conductor 35 is removed.

The method for manufacturing a conductive member according to this embodiment further includes a wiring formation process having the above steps, so that wiring 9 including a conductor 35 can be formed on the main surface of the metal-coated organic insulating film 40.

The conductive member 10 shown in FIG. 1 can be manufactured by preparing an organic insulating film 1 having through holes 30 and carrying out steps similar to the metal body forming step (filling step and baking step) described above. In addition, if necessary, steps similar to the resin impregnation step and resin curing step described above may be further carried out.

(Substrate having a through electrode according to an embodiment of a conductive member)
7(h) is a cross-sectional view showing one embodiment of a substrate having a through electrode that can be manufactured by the above-mentioned method for manufacturing a conductive member. The substrate 52 having a through electrode shown in FIG. 7(h) includes an organic insulating film 1 having a through hole 30, a base body having the through hole 30 on both main surfaces, and a conductor filling the through hole 30. The conductor 35 includes a copper sintered body having a porous structure and solder that is distributed discretely in the copper sintered body, in other words, present in a scattered manner, and includes a metal body 5 having voids 4, and the metal body 5 includes, as the voids 4, voids present inside the solder and/or voids present between the solder and the copper sintered body. The conductor 35 further includes a resin cured material 6 filled in the voids 4.

The substrate 52 having a through electrode shown in FIG. 7(h) has a metal coating 2 on both main surfaces of the organic insulating film 1 and on the wall surface of the through hole, but the metal coating 2 does not have to be provided on the main surfaces, it may be provided only on one main surface, or it may not be provided on the wall surface of the through hole. Also, the substrate 52 having a through electrode has wiring 9 including the metal coating 2 and the conductor 35 provided on both main surfaces of the metal-coated organic insulating film 40, but the wiring 9 may be provided on one main surface of the metal-coated organic insulating film 40.

The substrate 52 having a through electrode may have a filling rate of the cured resin 6 in the conductor that satisfies the following conditions. The filling rate can be calculated in the same manner as above.

(Through-hole conductor)
(a) In a region extending from a point S5 passing through a central portion C of the through hole 30 (the center of the hole length and the center of the hole diameter there) where a line L1 extending in the thickness direction of the substrate intersects with the surface of the conductor to a depth of 10 μm (see FIG. 7(h)), the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the internal space of the pores (voids) of the metal body.
(b) In the region from point S5 to a depth of 10 to 20 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(c) In the region from point S5 to a depth of 20 to 30 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(d) Within a range of ±5 μm from the center C of the through hole 30 in the thickness direction of the substrate and in a direction perpendicular to the thickness direction of the substrate, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

(Conductors on the main surface of the substrate)
(e) In a region from the surface S6 of the conductor formed on the main surface of the substrate to a depth of 5 μm (see FIG. 7 (h)), the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(f) In the region from the surface S6 of the conductor 35 formed on the main surface of the substrate to a depth of 10 μm, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(g) In the region 10 to 20 μm deep from the surface S6, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.
(h) In the region 20 to 30 μm deep from the surface S6, the filling rate of the cured resin may be 80 vol. % or more, 90 vol. % or more, or 95 vol. % or more, based on the total volume of the porous internal space of the metal body.

Furthermore, we will explain the conductive member and its manufacturing method.

The first conductive member may include an organic insulating film, a conductive portion penetrating the organic insulating film in the thickness direction, a metal body having a porous structure in which the conductive portion is provided to penetrate the organic insulating film in the thickness direction, and a solder-containing portion provided to cover at least a portion of one end or both ends of the metal body. The first conductive member may be used as an anisotropic conductive member.

Figure 8 is a schematic diagram showing one embodiment of the conductive member and its manufacturing method. The conductive member 42 shown in Figure 8 (c) comprises an organic insulating film 1, a metal body 5 having a porous structure arranged so as to penetrate the organic insulating film in the thickness direction, and a solder-containing portion 60 arranged so as to cover at least a part of both ends of the metal body 5, and the conductive portion is composed of the metal body 5 and the solder-containing portion 60. The conductive member 42 can be used as an anisotropic conductive member.

The organic insulating film, metal body, and solder-containing portion may have the same configuration as described above.

The method for manufacturing the first conductive member may include a preparation step of preparing an organic insulating film having through holes that communicate with both main surfaces, and a conductor formation step of forming a conductor in the through holes, the conductor formation step including a metal body formation step of forming a metal body having a porous structure in the through holes, and a second metal-containing portion formation step of forming a second metal portion that covers at least a portion of one or both ends of the metal body, the metal body formation step including a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form a metal body, and the second metal-containing portion formation step including a step of immersing the organic insulating film on which the metal body has been formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the metal body has been formed and heating the solder composition.

In the preparation step, as shown in FIG. 8(a), an organic insulating film 41 having through holes 30 can be prepared. The through holes 30 communicate with both main surfaces of the organic insulating film 41.

The organic insulating film 41 can be produced, for example, by exposing and developing a photosensitive insulating film containing the above-mentioned photosensitive resin composition using a known method.

The metal body forming process can be carried out in the same manner as the filling process and the firing process described above. For example, by filling the through-holes 30 of the organic insulating film 41 with a metal particle composition containing copper particles and solder and firing the filled metal particle composition, as shown in FIG. 8(b), a metal body-filled organic insulating film 10 can be obtained in which a copper sintered body having a porous structure, solder that is distributed discretely in the copper sintered body, in other words, present in a scattered manner, and a metal body 5 that includes voids (pores) 4 are provided in the through-holes 30. Note that the metal body can include, as the voids 4, the pores of the copper sintered body, voids present inside the solder, and voids present between the copper sintered body and the solder.

In the second metal-containing portion forming process, it is preferable to apply flux to the surface of the metal body and then immerse (dip) the organic insulating film on which the metal body is formed into a bath containing molten solder. In this way, as shown in FIG. 8(c), a solder-containing portion 60 can be formed as the second metal-containing portion.

The solder-containing portion can also be formed by placing a solder composition on an organic insulating film on which a metal body is formed, and then heating the solder composition. Examples of the solder composition include solder balls and pastes containing solder.

The second conductive member may include a metal body having a porous structure, the metal body including an organic insulating film and a conductive portion penetrating the organic insulating film in the thickness direction, the conductive portion being provided so as to penetrate the organic insulating film in the thickness direction, and an electroless plating coating provided so as to cover at least a portion of one end or both ends of the metal body.

The conductive portion may also include an electroless plating film provided to cover at least a portion of one or both ends of the metal body, and a solder-containing portion provided to cover the electroless plating film.

The organic insulating film, metal body, electroless plating film, and solder-containing portion may have the same configuration as described above.

Figure 9 is a schematic diagram showing one embodiment of the conductive member. The conductive member 43 shown in Figure 9 (a) comprises an organic insulating film 1, a metal body 5 having a porous structure that is arranged to penetrate the organic insulating film in the thickness direction, and an electroless plating coating 61 that is arranged to cover at least a portion of both ends of the metal body 5, and the conductive portion is composed of the metal body 5 and the electroless plating coating 61. The conductive member 43 can be used as an anisotropic conductive member.

The conductive member 44 shown in FIG. 9(b) includes an organic insulating film 1, a metal body 5 having a porous structure that is arranged to penetrate the organic insulating film in the thickness direction, an electroless plating coating 61 that is arranged to cover at least a portion of both ends of the metal body 5, and a solder-containing portion 60 that is arranged to cover the electroless plating coating 61, and the conductive portion is composed of the metal body 5, the electroless plating coating 61, and the solder-containing portion 60. The conductive member 44 can be used as an anisotropic conductive member.

The method for manufacturing the second conductive member may include a preparation step of preparing an organic insulating film having through holes that communicate with both main surfaces, and a conductor formation step of forming a conductor in the through holes, the conductor formation step including a metal body formation step of forming a metal body having a porous structure in the through holes, and a second metal-containing portion formation step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body, the metal body formation step including a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form a metal body, and the second metal-containing portion formation step including an electroless plating step of forming an electroless plating film so as to cover at least a portion of one end or both ends of the metal body, and a step of immersing the organic insulating film on which the electroless plating film has been formed in a bath containing molten solder, which may be provided as necessary, or a step of placing a solder composition on the organic insulating film on which the electroless plating film has been formed and heating the solder composition.

The preparation process and metal body formation process can be carried out in the same manner as in the manufacture of the first conductive member.

The electroless plating process may involve, for example, electroless nickel plating on the surface of the metal body 5 of the organic insulating film 41 in which the through holes 30 are provided, and, if necessary, electroless gold plating such as displacement gold plating, or electroless palladium plating and electroless gold plating, may be applied to the surface of the electroless nickel plating film. In this way, as shown in FIG. 9(a), an electroless plating film 61 can be formed as the second metal-containing portion.

Furthermore, when a solder-containing portion is provided, it is preferable to apply flux to the surface of the electroless plating film 61 of the conductive member 43 and then dip the conductive member 43 into a bath containing molten solder. In this way, as shown in FIG. 9(b), the electroless plating film 61 and the solder-containing portion 60 can be formed as the second metal-containing portion.

The solder-containing portion can also be formed by placing a solder composition on an organic insulating film on which an electroless plating film has been formed, and then heating the solder composition. Examples of the solder composition include solder balls and pastes containing solder.

In the manufacturing method of the first and second conductive members described above, the conductor forming process can include, between the metal body forming process and the second metal-containing portion forming process, a resin impregnation process for impregnating the metal body with a curable resin composition, and a resin curing process for curing the curable resin composition impregnated into the metal body.

The resin impregnation process and the resin curing process can be carried out in the same manner as described above. This allows the formation of a cured resin that exists within the pores of the metal body.

Figure 10 is a schematic diagram showing one embodiment of the manufacturing method of the conductive member. The substrate 45 shown in Figure 10 (a) shows a state after the resin impregnation process and the resin curing process are performed on the metal body-filled organic insulating film 10 shown in Figure 8 (b), and has a metal body 5 formed in the through hole 30 of the organic insulating film 1, in which the void is filled with a resin cured material 6, i.e., an organic insulating film through electrode, and a resin cured material 62 formed on both main surfaces of the organic insulating film 1. Note that the substrate 45 does not necessarily have to have a resin cured material 6 formed thereon.

When both sides of the organic insulating film 1 having an organic insulating film through electrode are covered with a cured resin 62, as shown in FIG. 10(b), at least a part of the metal body 5 can be exposed by removing the cured resin 62. Methods for removing the cured resin 62 include chemical polishing, mechanical polishing, chemical-mechanical polishing, plasma treatment, etc.

After the cured resin 62 is removed, the conductive member 47 can be obtained by the second metal-containing portion forming process described above, which includes a solder-containing portion 60 that is provided so as to cover at least a portion of both ends of the metal body 5, as shown in FIG. 10(c). The solder-containing portion 60 can also be formed by placing a solder composition on the metal body and heating the solder composition. Alternatively, instead of the solder-containing portion 60, an electroless plating film may be provided, or an electroless plating film and a solder-containing portion may be provided.

The first and second conductive members may have a resin layer provided on one or both main surfaces of the organic insulating film. The resin layer may be provided so as to cover the conductor, or may be provided so as to expose a portion of the covered conductor. For example, the resin layer may be provided so as to expose a portion of the solder-containing portion.

The conductive member having the resin layer described above can be obtained by a method including a preparation step of preparing an organic insulating film having through holes that connect to both main surfaces, and a conductor forming step of forming a conductor in the through hole, the conductor forming step including a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one or both ends of the metal body, the metal body forming step including a filling step of filling the through holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body, and the second metal-containing portion forming step including a step of applying a solder paste containing solder particles and a curable resin composition to one or both main surfaces of the organic insulating film on which the metal body is formed, and a step of heating the applied solder paste.

The preparation process and metal body formation process can be carried out in the same manner as in the manufacture of the first conductive member.

In the second metal-containing portion forming step, as shown in (a) and (b) of FIG. 11, first, a solder paste containing solder particles 63 and a curable resin composition 64 is applied to one of the main surfaces of the organic insulating film 1 on which the metal body is formed (coated body 48 of (a) of FIG. 11), and then a solder paste containing solder particles 63 and a curable resin composition 64 can be applied to the other main surface of the organic insulating film 1 (coated body 49 of (b) of FIG. 11). As shown in (a) of FIG. 11, in some cases, the curable resin composition 66 that has permeated into the pores of the metal body may reach the surface opposite to the surface coated the first time. The solder paste can also be applied in a predetermined pattern. The solder paste will be described later.

Next, the coating body 49 is heated to heat the solder paste to a temperature equal to or higher than the melting point of the solder, thereby forming a solder-containing portion 60 that covers both ends of the metal body in the through hole 30 and a resin layer 67 that contains a semi-cured resin, as shown in FIG. 12(c), and the curable resin composition that has permeated the pores of the metal body becomes a semi-cured resin 68. At this time, the semi-cured resin 67, 68 may be a cured resin. When a cured resin is formed, the cured resin may be partially removed to provide a resin layer 69 that exposes at least a part of the solder-containing portion 60, as shown in FIG. 12(d). Methods for removing the cured resin include chemical polishing, mechanical polishing, chemical mechanical polishing, plasma treatment, and the like. The conductive members 70, 72 shown in FIG. 12(c) and (d) can be used as anisotropic conductive members.

13 is a schematic diagram for explaining the manufacturing of the conductive member described above, and shows the mechanism by which the adhesion between the metal body 5 and the organic insulating film 1 is improved by the second metal-containing portion forming process. As shown in FIG. 13(a), holes 4 and holes 80 are formed in the metal body 5 after the metal body forming process. By applying a solder paste containing solder particles 63 and a curable resin composition 64 to the main surface of the organic insulating film 1, the curable resin composition 81 can reach the void portion of the metal body 5 that is in contact with the inner wall of the through hole of the organic insulating film 1, as shown in FIG. 13(b). Next, by heating the applied solder paste, resin semi-cured products 67, 68, and 82 are formed as shown in FIG. 13(c). At this time, it is considered that the adhesiveness between the metal body 5 and the organic insulating film 1 is improved by the resin semi-cured product 82 formed in the void portion of the metal body 5 that is in contact with the inner wall of the through hole of the organic insulating film 1. Furthermore, it is considered that the adhesiveness is further improved by making the resin semi-cured product into a resin cured product. It is believed that this improved adhesion is one of the reasons why it is easier to obtain conductive members whose connection resistance is less likely to increase even when deformed.

<Semiconductor Device>
The semiconductor device of this embodiment has a connection structure in which a semiconductor chip and a support member for mounting a semiconductor chip are electrically connected to each other via the above-mentioned conductive member, and/or a connection structure in which multiple semiconductor chips are electrically connected to each other via the above-mentioned conductive member.

Semiconductor chips include those made from silicon wafers, silicon carbide wafers, gallium nitride wafers, etc.

Examples of support members for mounting semiconductor chips include glass epoxy substrates, polyimide substrates, polyethylene terephthalate substrates, and polyethylene naphthalate substrates.

Figure 14 is a schematic diagram showing a method for manufacturing a semiconductor device using the conductive member 70 described above as an anisotropic conductive member. First, a semiconductor chip 90 provided with an electrode 84 and a semiconductor package 91 provided with an electrode 86 are arranged so that the electrodes face each other, and a conductive member 70 is interposed between these electrodes (Figure 14 (a)). Then, by applying pressure from above and below, the electrode 84 and the solder-containing portion 60, and the electrode 86 and the solder-containing portion 60 can be electrically connected, and by further applying pressure and heat, the resin layer 67 becomes a resin cured material 87, and a connection structure can be formed in which the semiconductor chip 90 and the conductive member 70, and the semiconductor package 91 and the conductive member 70 are firmly connected (Figure 14 (b)).

Metal Particle Composition
The metal particle composition containing copper particles or copper particles and solder particles, which is used in the above-mentioned method for producing a conductive member, will be described below.

The metal particle composition may contain, as the copper particles, first copper particles having a particle size (maximum diameter) of 0.8 μm or more.

The particle size (maximum diameter) of the first copper particles may be 1.2 μm or more. The particle size (maximum diameter) of the first copper particles may be 10 μm or less, or 8.0 μm or less.

The average particle size (average maximum diameter) of the first copper particles contained in the metal particle composition may be 0.8 μm or more or 1.2 μm or more, and may be 10 μm or less or 8 μm or less, from the viewpoint of improving the sintering density in the through holes and suppressing the generation of voids in the through holes.

The particle size (maximum diameter) and average particle size (average maximum diameter) of the first copper particles can be determined, for example, from an SEM image of the particles. An example of a method for calculating the particle size (maximum diameter) of the first copper particles from an SEM image is shown below. A powder of the first copper particles is placed on a carbon tape for SEM with a spatula to prepare a sample for SEM. This sample for SEM is observed at 5000 times magnification with an SEM device. A rectangle circumscribing the first copper particle in the SEM image is drawn using image processing software, and the long side of the rectangle is taken as the particle size (maximum diameter) of the particle. This measurement is performed on 50 or more first copper particles using multiple SEM images, and the average particle size (average maximum diameter) is calculated.

The shape of the first copper particles may be, for example, spherical, clumpy, needle-like, flat (flake-like), approximately spherical, etc. The first copper particles may be an agglomerate of copper particles having these shapes.

The first copper particles are preferably flat (flake-like). In this case, the first copper particles are oriented approximately parallel to the coating surface of the metal particle composition, which suppresses volumetric shrinkage when the copper particles in the metal particle composition are sintered, making it easier to suppress voids from occurring in the through holes. In addition, suppressing volumetric shrinkage when the copper particles in the metal particle composition are sintered can suppress cracks in the metal body formed on at least one of the main surfaces of the substrate (e.g., an organic insulating film).

The aspect ratio of the first copper particles may be 4 or more, or may be 6 or more. If the aspect ratio is within the above range, the first copper particles in the metal particle composition are more likely to be oriented parallel to the coating surface of the metal particle composition, and volume shrinkage when the copper particles in the metal particle composition are sintered can be suppressed. This makes it possible to further suppress breakage of the wiring due to thermal stress when wiring is formed from a conductor provided on the main surface of a substrate (e.g., an organic insulating film). In addition, the adhesion between the metal body and the metal coating formed on the substrate (e.g., an organic insulating film) can be improved. The aspect ratio (major axis/thickness) of the copper particles in the metal particle composition can be determined, for example, by observing an SEM image of the particles and measuring the major axis and thickness.

The metal particle composition preferably contains first copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of 4 or more. By containing such first copper particles in the metal particle composition, the volume shrinkage when the copper particles in the metal particle composition are sintered can be sufficiently reduced, and it becomes easy to form a metal body in the through hole having a porous structure and a sufficiently formed conductive network. As a result, it is possible to suppress the generation of voids in the through hole, and it is possible to form a metal body on the main surface of the base (e.g., an organic insulating film) that is less likely to crack, and when wiring is formed from a conductor containing this metal body, it is possible to further suppress breakage of the wiring due to thermal stress.

The metal particle composition may contain copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of less than 2, but the content of the copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of less than 2 is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of the first copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of 4 or more. By limiting the content of the copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of less than 2, it is possible to form a metal body in the through hole having a porous structure while having a sufficiently formed conductive network, while suppressing the generation of voids in the through hole by the first copper particles in the metal particle composition. Furthermore, on the main surface of the substrate (e.g., an organic insulating film), the first copper particles tend to be oriented approximately parallel to the surface to which the metal particle composition is applied, and volumetric shrinkage is more effectively suppressed, forming a metal body that is less susceptible to cracking. When wiring is formed from a conductor containing this metal body, breakage of the wiring due to thermal stress can be further suppressed.

In order to make such effects more easily obtainable, the content of the copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of less than 2 may be 20 parts by mass or less, 10 parts by mass or less, or even 0 parts by mass per 100 parts by mass of the first copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of 4 or more.

The content of the first copper particles in the metal particle composition may be 15% by mass or more, 20% by mass or more, or 50% by mass or more, and may be 85% by mass or less, 70% by mass or less, or 50% by mass or less, based on the total mass of the metal particles contained in the metal particle composition. If the content of the first copper particles is within the above range, the above-mentioned effects are more easily obtained.

The first copper particles may be treated with a surface treatment agent from the viewpoint of dispersion stability and oxidation resistance. The surface treatment agent may be one that is removed during wiring formation (when sintering the copper particles). Examples of such surface treatment agents include aliphatic carboxylic acids such as palmitic acid, stearic acid, arachidic acid, and oleic acid; aromatic carboxylic acids such as terephthalic acid, pyromellitic acid, and o-phenoxybenzoic acid; aliphatic alcohols such as cetyl alcohol, stearyl alcohol, isobornylcyclohexanol, and tetraethylene glycol; aromatic alcohols such as p-phenylphenol; alkylamines such as octylamine, dodecylamine, and stearylamine; aliphatic nitriles such as stearonitrile and decanenitrile; silane coupling agents such as alkylalkoxysilanes; and polymer treatment agents such as polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and silicone oligomers. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

The amount of the surface treatment agent may be an amount equal to or greater than one molecular layer on the particle surface. The amount of such a surface treatment agent varies depending on the specific surface area of the first copper particles, the molecular weight of the surface treatment agent, and the minimum coverage area of the surface treatment agent. The amount of the surface treatment agent is usually 0.001% by mass or more.

The treatment amount of the surface treatment agent is determined by the number of molecular layers (n) attached to the surface of the first copper particle, the specific surface area (A _p ) (unit: m ² /g) of the first copper particle, the molecular weight (M _s ) (unit: g/mol) of the surface treatment agent, the minimum coverage area (S _S ) (unit: m ² /particle) of the surface treatment agent, and the Avogadro's number (N _A ).
Specifically, the treatment amount of the surface treatment agent is calculated according to the ^formula : Treatment amount of surface treatment agent (mass%)={(n·A _p ·M _s )/( _SS ·N _A + n·A _p ·M _s )}×100%.

The specific surface area of the first copper particles can be calculated by measuring the dried copper particles by the BET specific surface area measurement method. The minimum coverage area of the surface treatment agent is 2.05×10 ⁻¹⁹ m ² /1 molecule when the surface treatment agent is a linear saturated fatty acid. In the case of other surface treatment agents, the surface area can be measured, for example, by calculation from a molecular model or by the method described in "Chemistry and Education" (Katsuhiro Ueda, Sumio Inafuku, Iwao Mori, 40 (2), 1992, pp. 114-117). An example of a method for quantifying the surface treatment agent is shown below. The surface treatment agent can be identified by a thermal desorption gas/gas chromatograph mass spectrometer of a dried powder obtained by removing the dispersion medium from the metal particle composition, and the carbon number and molecular weight of the surface treatment agent can be determined. The carbon content of the surface treatment agent can be analyzed by carbon content analysis. Examples of carbon content analysis methods include high-frequency induction heating furnace combustion/infrared absorption method. The amount of the surface treatment agent can be calculated from the carbon number, molecular weight and carbon content of the identified surface treatment agent according to the above formula.

Commercially available first copper particles can be used. Examples of commercially available first copper particles include MA-C025 (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size 4.1 μm), 3L3 (manufactured by Fukuda Metal Foil & Powder Co., Ltd., average particle size 7.3 μm), 1110F (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size 5.8 μm), and 2L3 (manufactured by Fukuda Metal Foil & Powder Co., Ltd., average particle size 9 μm).

When producing the metal particle composition, copper particles can be used that contain first copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of 4 or more, and the content of copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of less than 2 is 50 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the first copper particles having a particle size (maximum diameter) of 0.8 μm or more and 10 μm or less and an aspect ratio of 4 or more. A commercially available product containing such copper particles as a main component may be selected and used.

The ratio (maximum diameter) of the pore size of the through holes to the particle size (maximum diameter) of the first copper particles (pore size (μm)/particle size (μm)) may be 4 or more, 8 or more, or 10 or more, and may be 150 or less, 100 or less, or 50 or less, from the viewpoint of suppressing volumetric shrinkage and forming a metal body that is less susceptible to cracking.

In one embodiment, the metal particle composition may include the first copper particles described above and second copper particles having a particle size (maximum diameter) of 0.5 μm or less. In this case, when the copper particles are sintered, the second copper particles are present between the first copper particles, which tends to improve the conductivity of the resulting wiring. That is, it is preferable to use the first copper particles and the second copper particles in combination. When preparing a metal particle composition containing only the second copper particles as copper particles, the volume shrinkage and sintering shrinkage associated with drying of the dispersion medium are large, so that when the copper particles are sintered, the sintered body is easily peeled off from the metal coating provided on the insulating base (e.g., organic insulating film), making it difficult to obtain sufficient airtightness and connection reliability. However, by using the first copper particles and the second copper particles in combination, the volume shrinkage when the metal particle composition is sintered is suppressed, and the adhesion between the metal body formed in the through hole and the metal coating formed on the wall surface of the through hole can be improved. This makes it less likely that the copper sintered body in the through hole will break due to thermal stress, further improving airtightness and connection reliability against thermal stress.

The second copper particles can act as copper particles that suitably bond the first copper particles together. In addition, the second copper particles have better sinterability than the first copper particles and can have the function of promoting the sintering of the copper particles. For example, compared to the case where the first copper particles are used alone as the copper particles, it becomes possible to sinter the copper particles at a lower temperature. In addition, when preparing a metal particle composition containing only the second copper particles as the copper particles, the volume shrinkage and sintering shrinkage caused by drying the dispersion medium are large, so that the metal body formed inside the through hole tends to shrink in volume, thereby causing voids inside the through hole. In particular, by using the flat first copper particles and the second copper particles in combination, the flat first copper particles act as copper particles that are suitably bonded by the second copper particles, and it becomes easy to form a metal body having voids (porous structure) while suppressing the generation of voids inside the through hole.

The average particle size (average maximum diameter) of the second copper particles contained in the metal particle composition may be 0.01 μm or more, 0.03 μm or more, 0.05 μm or more, or 0.08 μm or more, and may be 0.5 μm or less, 0.4 μm or less, 0.3 μm or less, or 0.2 μm or less.

If the average particle size (average maximum diameter) of the second copper particles is 0.01 μm or more, it is easy to obtain effects such as reducing the synthesis cost of the second copper particles, good dispersibility, and reducing the amount of surface treatment agent used. If the average particle size (average maximum diameter) of the second copper particles is 0.5 μm or less, it is easy to obtain the effect of excellent sintering properties of the second copper particles. From the viewpoint of further achieving the above effects, the average particle size (average maximum diameter) of the second copper particles may be 0.05 μm or more, 0.1 μm or more, or 0.2 μm or more, and may be 0.5 μm or less, 0.4 μm or less, or 0.3 μm or less.

The second copper particles may contain 20% by mass or more of copper particles having a particle size (maximum diameter) of 0.01 μm or more and 0.5 μm or less. From the viewpoint of the sinterability of the metal particle composition, the second copper particles may contain 30% by mass or more, 50% by mass or more, or 85% by mass or less of copper particles having a particle size (maximum diameter) of 0.01 μm or more and 0.5 μm or less. When the content ratio of copper particles having a particle size (maximum diameter) of 0.01 μm or more and 0.5 μm or less in the second copper particles is 20% by mass or more, the dispersibility of the copper particles is further improved, and the increase in viscosity and the decrease in paste concentration can be further suppressed.

The content of the second copper particles in the metal particle composition may be 20% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more, and 85% by mass or less, 80% by mass or less, or 75% by mass or less, based on the total mass of the metal particles contained in the metal particle composition. If the content of the second copper particles is within the above range, it is easy to form a metal body that has excellent adhesion to the metal coating provided on the base (e.g., an organic insulating film) while suppressing the generation of voids in the through holes, and a copper sintered body that is less likely to crack on the main surface of the base (e.g., an organic insulating film) can be formed, and when wiring is formed from a conductor containing this copper sintered body, breakage of the wiring due to thermal stress can be further suppressed.

The content of the second copper particles in the metal particle composition may be 20% by mass or more and 85% by mass or less, based on the sum of the mass of the first copper particles and the mass of the second copper particles. If the content of the second copper particles is 20% by mass or more, the spaces between the first copper particles can be sufficiently filled, a metal body that is less likely to crack can be formed, and wiring formed from a conductor containing this metal body is less likely to break due to thermal stress. If the content of the second copper particles is 85% by mass or less, volumetric shrinkage when the copper particles are sintered can be sufficiently suppressed, so that the generation of voids in the through holes can be suppressed and a metal body that is less likely to crack can be formed, and wiring formed from a conductor containing this metal body is less likely to break due to thermal stress.

In order to make the above-mentioned effect more easily obtainable, the content of the second copper particles may be 30% by mass or more, 35% by mass or more, or 40% by mass or more, based on the total mass of the first copper particles and the second copper particles, and may be 85% by mass or less, or 80% by mass or less.

The shape of the second copper particles may be, for example, spherical, lump-like, needle-like, flat (flake-like), approximately spherical, etc. The second copper particles may be an aggregate of copper particles having these shapes.
From the viewpoints of dispersibility and packing ability, the shape of the second copper particles may be spherical, approximately spherical, or flat (flake-like), and from the viewpoints of combustibility and mixability with the first copper particles, the shape may be spherical or approximately spherical.

The aspect ratio of the second copper particles may be 5 or less, or may be 3 or less, from the viewpoints of dispersibility, packing ability, and mixability with the first copper particles.

The second copper particles may be treated with a specific surface treatment agent. Examples of specific surface treatment agents include organic acids having 8 to 16 carbon atoms. Examples of organic acids having 8 to 16 carbon atoms include caprylic acid, methylheptanoic acid, ethylhexanoic acid, propylpentanoic acid, pelargonic acid, methyloctanoic acid, ethylheptanoic acid, propylhexanoic acid, capric acid, methylnonanoic acid, ethyloctanoic acid, propylheptanoic acid, butylhexanoic acid, undecanoic acid, methyldecanoic acid, ethylnonanoic acid, propyloctanoic acid, butylheptanoic acid, lauric acid, methylundecanoic acid, ethyldecanoic acid, propylnonanoic acid, butyloctanoic acid, Saturated fatty acids such as pentylheptanoic acid, tridecanoic acid, methyldodecanoic acid, ethylundecanoic acid, propyldecanoic acid, butylnonanoic acid, pentyloctanoic acid, myristic acid, methyltridecanoic acid, ethyldodecanoic acid, propylundecanoic acid, butyldecanoic acid, pentylnonanoic acid, hexyloctanoic acid, pentadecanoic acid, methyltetradecanoic acid, ethyltridecanoic acid, propyldodecanoic acid, butylundecanoic acid, pentyldecanoic acid, hexylnonanoic acid, palmitic acid, methylpentadecanoic acid, ethyltetradecanoic acid, propyltridecanoic acid, butyldodecanoic acid, pentylundecanoic acid, hexyldecanoic acid, heptylnonanoic acid, methylcyclohexanecarboxylic acid, ethylcyclohexanecarboxylic acid, propylcyclohexanecarboxylic acid, butylcyclohexanecarboxylic acid, pentylcyclohexanecarboxylic acid, hexylcyclohexanecarboxylic acid, heptylcyclohexanecarboxylic acid, octylcyclohexanecarboxylic acid, and nonylcyclohexanecarboxylic acid; octene Examples of the organic acid include unsaturated fatty acids such as ethyl benzoic acid, nonenoic acid, methylnonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, myristoleic acid, pentadecenoic acid, hexadecenoic acid, palmitoleic acid, and sapienic acid; and aromatic carboxylic acids such as terephthalic acid, pyromellitic acid, o-phenoxybenzoic acid, methylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, pentylbenzoic acid, hexylbenzoic acid, heptylbenzoic acid, octylbenzoic acid, and nonylbenzoic acid. The organic acid may be used alone or in combination of two or more. By combining such an organic acid with the second copper particles, it tends to be possible to achieve both the dispersibility of the second copper particles and the detachment of the organic acid during sintering.

The amount of the surface treatment agent may be an amount that adheres to the surface of the second copper particles in a monolayer to trilayer form. The amount of the surface treatment agent may be 0.07% by mass or more, 0.10% by mass or more, or 0.2% by mass or more, and may be 2.1% by mass or less, 1.6% by mass or less, or 1.1% by mass or less. The amount of the surface treatment agent of the second copper particles can be calculated by the method described above for the first copper particles. The same applies to the specific surface area, the molecular weight of the surface treatment agent, and the minimum coverage area of the surface treatment agent.

The second copper particles can be synthetic or commercially available.

The sum of the content of the first copper particles and the content of the second copper particles in the metal particle composition may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or 93% by mass or more based on the total mass of the metal particles contained in the metal particle composition. If the sum of the content of the first copper particles and the content of the second copper particles is within the above range, it is easier to suppress the generation of voids in the through holes. From the viewpoint of making such an effect even easier to obtain, the sum of the content of the first copper particles and the content of the second copper particles may be 80% by mass or more, 90% by mass or more, or 95% by mass or more based on the total mass of the metal particles.

The solder particles may contain tin or a tin alloy, such as In-Sn, In-Sn-Ag, Sn-Bi, Sn-Bi-Ag, Sn-Ag-Cu, or Sn-Cu alloys, including the following examples:
In-Sn (In 52% by mass, Bi 48% by mass, melting point: 118°C)
・In-Sn-Ag (20% by mass of In, 77.2% by mass of Sn, 2.8% by mass of Ag, melting point: 175°C)
・ Sn-Bi (Sn 43% by mass, Bi 57% by mass, melting point: 138°C)
Sn-Bi-Ag (Sn 42% by mass, Bi 57% by mass, Ag 1% by mass, melting point: 139°C)
・Sn-Ag-Cu (96.5% by mass of Sn, 3% by mass of Ag, 0.5% by mass of Cu, melting point: 217°C)
・ Sn-Cu (Sn 99.3 mass%, Cu 0.7 mass%, melting point: 227 ° C.)

The metal particle composition may contain solder particles having a particle size (maximum diameter) of 1.0 μm or more, for example.

The particle size (maximum diameter) of the solder particles may be 2 μm or more, 15 μm or less, or 8.0 μm or less.

The average particle size (average maximum diameter) of the solder particles contained in the metal particle composition may be 1.0 μm or more, 2.0 μm or more, 15 μm or less, or 8 μm or less, from the viewpoint of suppressing volumetric shrinkage due to sintering in the through holes and suppressing voids occurring in the through holes. By using solder particles with such a particle size, the volumetric shrinkage when the copper particles in the metal particle composition are sintered can be sufficiently reduced, and it becomes easy to form a metal body in the through holes that has a porous structure and a sufficiently formed conductive network. As a result, it is possible to suppress the generation of voids in the through holes and form a metal body that is less likely to crack on the main surface of the base (e.g., an organic insulating film), and when wiring is formed from a conductor containing this metal body, breakage of the wiring due to thermal stress can be further suppressed.

It is preferable that the particle size of the solder particles is uniform. In this case, the solder particles are easily dispersed and scattered inside the metal body, and voids are generated inside the scattered solder or on the outer periphery of the solder (between the solder and the copper sintered body), which suppresses the generation of continuous voids and cracks longer than 5 μm, and suppresses breaks inside the vias and breaks in the wiring formed on the main surface of the substrate (e.g., organic insulating film).

The particle size (maximum diameter) and average particle size (average maximum diameter) of solder particles can be calculated from SEM images, for example, by the following procedure. A powder of solder particles is placed on carbon tape for SEM with a spatula to prepare an SEM sample. This SEM sample is observed at 5000x magnification with an SEM device. A rectangle circumscribing the solder particle in the SEM image is drawn using image processing software, and the long side of the rectangle is taken as the particle size (maximum diameter) of that particle. This measurement is performed on 50 or more solder particles using multiple SEM images, and the average particle size (average maximum diameter) is calculated.

The shape of the solder particles may be, for example, spherical, clumpy, needle-like, flat (flake-like), approximately spherical, etc. The solder particles may also be an agglomerate of solder particles having these shapes.

The solder particles are preferably spherical. In this case, the solder particles are uniformly dispersed inside the metal body, and voids are generated inside the uniformly dispersed solder or on the outer periphery of the solder (between the solder and the copper sintered body), which suppresses volumetric shrinkage when the copper particles in the metal particle composition are sintered, making it easier to suppress breaks in the through holes. In addition, suppressing volumetric shrinkage when the copper particles in the metal particle composition are sintered can suppress cracks in the metal body formed on at least one main surface of the substrate (e.g., an organic insulating film).

The content of the solder particles in the metal particle composition may be 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more, and 25 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less, relative to 100 parts by mass of the copper particles contained in the metal particle composition. If the content of the solder particles is within the above range, the above-mentioned effect is more easily obtained. That is, it is easy to form a metal body in the through hole in which a conductive network is sufficiently formed while having a porous structure, while suppressing the generation of voids in the through hole. In addition, when the metal particle composition contains the above-mentioned first copper particles, the first copper particles are likely to be oriented approximately parallel to the coating surface of the metal particle composition on the main surface of the substrate (e.g., an organic insulating film), and volume shrinkage can be more effectively suppressed to form a metal body that is less likely to crack, and when wiring is formed from a conductor containing this metal body, breakage due to thermal stress of the wiring can be further suppressed. If the content of the solder particles is 1 part by mass or more per 100 parts by mass of the copper particles, it becomes easier to suppress the generation of voids inside the metal body, and it becomes easier to prevent, for example, the generation of cracks longer than 5 μm and the occurrence of breaks inside the via. On the other hand, if the content of the solder particles is 25 parts by mass or less per 100 parts by mass of the copper particles, the resistivity of the wiring is less likely to increase.

In the metal particle composition, the total content of the copper particles (preferably the content of the first copper particles and the content of the second copper particles) and the content of the solder particles may be 90 mass% or more based on the total mass of the metal particles contained in the metal particle composition. In this case, it is easier to suppress the occurrence of voids in the through holes. From the viewpoint of making such an effect even easier to obtain, the total content of the copper particles (preferably the content of the first copper particles and the content of the second copper particles) and the content of the solder particles may be 95 mass% or more, or may be 100 mass%, based on the total mass of the metal particles.

The metal particle composition may further contain other metal particles other than copper particles and solder particles. Examples of other metal particles include nickel, silver, gold, palladium, platinum, and the like. The average particle size (maximum diameter) of the other metal particles may be 0.01 μm or more or 0.05 μm or more, and may be 5 μm or less, 3.0 μm or less, or 2.0 μm or less. When other metal particles are contained, the content thereof may be less than 20 mass% and may be 10 mass% or less based on the total mass of the metal particles contained in the metal particle composition from the viewpoint of obtaining sufficient bonding properties. Other metal particles may not be contained. The shape of the other metal particles is not particularly limited.

The metal particle composition may contain a dispersion medium. The dispersion medium is not particularly limited, and may be, for example, a volatile one. Examples of volatile dispersion media include monohydric and polyhydric alcohols such as pentanol, hexanol, heptanol, octanol, decanol, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, α-terpineol, and isobornylcyclohexanol (MTPH); ethylene glycol butyl ether, ethylene glycol phenyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol isobutyl ether, diethylene glycol hexyl ether, triethylene glycol methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl ether, propylene glycol propyl ether, and dipropylene glycol. Examples of the esters include methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, and tripropylene glycol dimethyl ether; esters such as ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dipropylene glycol methyl ether acetate (DPMA), ethyl lactate, butyl lactate, γ-butyrolactone, and propylene carbonate; acid amides such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide; aliphatic hydrocarbons such as cyclohexane, octane, nonane, decane, and undecane; aromatic hydrocarbons such as benzene, toluene, and xylene; mercaptans having an alkyl group having 1 to 18 carbon atoms; and mercaptans having a cycloalkyl group having 5 to 7 carbon atoms. Examples of mercaptans having an alkyl group having 1 to 18 carbon atoms include ethyl mercaptan, n-propyl mercaptan, i-propyl mercaptan, n-butyl mercaptan, i-butyl mercaptan, t-butyl mercaptan, pentyl mercaptan, hexyl mercaptan, and dodecyl mercaptan.
Examples of mercaptans having a cycloalkyl group having 5 to 7 carbon atoms include cyclopentyl mercaptan, cyclohexyl mercaptan, and cycloheptyl mercaptan.

The content of the dispersion medium may be 3 parts by mass or more, 5 parts by mass or more, 20 parts by mass or less, or 12 parts by mass or less, assuming that the total mass of the metal particles contained in the metal particle composition is 100 parts by mass. If the content of the dispersion medium is within these ranges, the viscosity of the metal particle composition can be adjusted to a more appropriate value, making it easier to suppress the occurrence of voids in the through holes.

If necessary, the metal particle composition may contain appropriate additives such as wetting enhancers, such as nonionic surfactants and fluorosurfactants; antifoaming agents, such as silicone oil; and ion trapping agents, such as inorganic ion exchangers.

The metal particle composition described above can be prepared by mixing copper particles, solder particles, and any optional components (additives, other metal particles, etc.) in a dispersion medium. After mixing the components, a stirring process may be performed. The maximum particle size of the dispersion may be adjusted by a classification operation.

When the metal particle composition contains the above-mentioned first copper particles and second particles, the second copper particles, the surface treatment agent, and the dispersion medium may be mixed in advance, and a dispersion treatment may be performed to prepare a dispersion of the second copper particles, and the first copper particles, solder particles, and other metal particles and optional additives may be further mixed to prepare the dispersion. By using such a procedure, the dispersibility of the second copper particles is improved, improving the mixability with the first copper particles, and the performance of the metal particle composition is further improved. The dispersion of the second copper particles may be subjected to a classification operation to remove aggregates.

The metal particle composition of this embodiment may not contain a curable resin component, or may contain a curable resin component in an amount of 4% by mass or less or 2% by mass or less based on the total amount of the composition.

<Solder paste>
The solder paste containing solder particles and a curable resin composition, which is used in the above-mentioned method for producing a conductive member, will now be described.

The solder particles can be the same as those described above.

The content of solder particles in the solder paste may be 50 parts by mass or more, 60 parts by mass or more, or 70 parts by mass or more based on the total amount of solder paste from the viewpoint of improving the solder joint reliability at the joint, and may be 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less based on the total amount of solder paste from the viewpoint of improving the permeability into the pores of the metal body and making it easier to suppress breaks inside the vias and breaks in the wiring.

The curable resin composition may be the same as the curable resin composition used in the resin impregnation step described above.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

<Synthesis of second copper particles>
150 mL of 1-propanol (Kanto Chemical Co., Ltd., special grade) was added to 91.5 g (0.94 mol) of copper hydroxide (Kanto Chemical Co., Ltd., special grade) and stirred, and 370.9 g (2.34 mol) of nonanoic acid (Kanto Chemical Co., Ltd., 90% or more) was added to the mixture. The resulting mixture was heated and stirred at 90°C for 30 minutes in a separable flask. The resulting solution was filtered while still heated to remove undissolved matter. It was then allowed to cool, and the resulting copper nonanoate was suction filtered and washed with hexane until the washing liquid became transparent. The resulting powder was dried in an explosion-proof oven at 50°C for 3 hours to obtain copper nonanoate (II). The yield was 340 g (yield 96% by mass).

15.01 g (0.040 mol) of copper (II) nonanoate obtained above and 7.21 g (0.040 mol) of copper (II) acetate anhydride (Kanto Chemical Co., Ltd., special grade) were placed in a separable flask, 22 mL of 1-propanol and 32.1 g (0.32 mol) of hexylamine (Tokyo Chemical Industry Co., Ltd., purity 99%) were added, and the mixture was heated and stirred at 80°C in an oil bath to dissolve. The mixture was transferred to an ice bath and cooled to an internal temperature of 5°C, and then 7.72 mL (0.16 mol) of hydrazine monohydrate (Kanto Chemical Co., Ltd., special grade) was stirred in the ice bath. The molar ratio of copper:hexylamine was 1:4. The mixture was then heated and stirred at 90°C in an oil bath. At that time, a reduction reaction accompanied by foaming proceeded, and the reaction was completed within 30 minutes. The inner wall of the separable flask exhibited a copper luster, and the solution turned dark red. Centrifugation was carried out at 9000 rpm (revolutions per minute) for 1 minute to obtain a solid. The process of washing the solid with 15 mL of hexane was repeated three times to remove the acid residue and obtain a powder of copper particles with a copper luster (second copper particles).

The copper particles synthesized above were observed with a transmission electron microscope (manufactured by JEOL Ltd., product name: JEM-2100F). The average major axis length of 200 randomly selected copper particles was 104 nm. The shape of the second particles was spherical.

<Preparation of Metal Particle Composition>
(Examples 1 to 10)
The raw materials shown below were mixed in the ratios shown in Table 1 to prepare metal particle compositions.

[First copper particles]
Flat 1.4 μm: 1100YP (manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size 1.4 μm (D50), product name)

[Second copper particles]
Spherical 104 nm: Copper particles synthesized above

[Solder particles]
SnBi58: SnBi58 solder STC-3 (manufactured by Mitsui Mining & Smelting Co., Ltd., product name, average particle size 4.1 μm (D50), spherical)

[others]
Diethylene glycol: Fujifilm Wako Pure Chemical Industries, Ltd.

[Preparation of anisotropic conductive member]
<Preparation process of organic insulating film>
(Examples 1 to 10)
A photosensitive resin composition (AH-3000: manufactured by Hitachi Chemical Co., Ltd.) was applied to one side of a 200 mm square PET (A4100: manufactured by Cosmoshine, manufactured by Toyobo Co., Ltd.) and exposed to light at 500 mJ/ ^cm2 to produce an organic insulating film with a PET film having a thickness of 50 μm and an opening (through hole) of 30 μmφ. The openings (through holes) were formed at a pitch of 100 μm.

<Metal body forming process>
(Examples 1 to 10)
-Filling process-
The prepared metal particle composition was applied to the opening of the PET-attached organic insulating film using a metal spatula to fill the opening. At this time, the metal particle composition attached to the surface of the organic insulating film was removed. After application, the metal particle composition was dried in the air at 90° C. for 10 minutes.

- Firing process -
The organic insulating film with PET on which the metal particle composition layer was formed was placed in a formic acid baking furnace (manufactured by Ayumi Industries Co., Ltd.). The metal particle composition was then sintered by heating for 20 minutes and sintering at 150°C for 60 minutes while flowing formic acid gas at 5 mL/min. The film was then cooled and taken out into air at 50°C or less to obtain an organic insulating film with PET filled with a metal body.

<Second metal-containing part forming step>
Example 1
Solder paste A containing solder particles and a curable resin composition having the following composition was applied to one side of the metal-filled organic insulating film by stencil printing using a metal squeegee to a thickness of 12 μm. Thereafter, a heat treatment was performed at 150° C. for 10 minutes while flowing nitrogen gas at 50 mL/min, to form a resin layer (semi-cured resin) on one side of the organic insulating film. Solder was formed in the holes of the metal body, and a semi-cured resin was formed in the holes of the metal body.
[Solder paste A]
Solder particles: Sn42-Bi58 particles (average particle size 20 μm), 70 parts by mass Bisphenol F type epoxy resin: YDF-170 (manufactured by Tohto Kasei Co., Ltd., product name, epoxy equivalent = 170), 25.2 parts by mass Imidazole compound: 2PZ -CN (trade name, manufactured by Shikoku Kasei Corporation), 1.3 parts by mass 2,2-bishydroxymethylpropionic acid (BHPA), 3.5 parts by mass

Furthermore, the resin layer on the solder surface was removed by reactive ion etching (RIE) under the conditions shown below to expose the solder. The thickness of the resin layer after the surface was removed was 8 μm.
Device name: Plasma cleaning device (Sanyo High Technology, SPC-100B)
Power: 600W
Gas and flow rate: Ar, 5 SCCM
Processing time: 5 minutes

Next, the PET film was peeled off from the metal body-filled organic insulating film with PET on one side of which solder and a resin layer were formed. A resin layer was formed on the surface of the metal body-filled organic insulating film that had been in contact with the PET film in the same manner as described above, and solder was formed on the metal body. Next, the resin layer was removed in the same manner as described above, exposing the solder.

<Resin impregnation step, resin curing step, and second metal-containing portion forming step>
Example 2
The PET film was peeled off from the metal body-filled PET-attached organic insulating film, and the curable resin composition shown below was applied to one side of the metal body-filled organic insulating film by a roll coater. Next, the metal body-filled organic insulating film was placed in a container, and the container was suctioned so that the gauge pressure was 100 KPa to create a vacuum state. The metal body-filled organic insulating film was held in a vacuum state for 10 minutes, and then the metal body-filled organic insulating film was removed from the container. It was confirmed that the curable resin composition was impregnated into the metal body of the through hole, and that the curable resin composition had reached the surface opposite to the surface of the metal body of the through hole to which the curable resin composition was applied. Next, the curable resin composition remaining on the surface of the metal body-filled organic insulating film to which the curable resin composition was applied was removed with a rubber spatula.
[Curable resin composition]
Bisphenol F type epoxy resin: YDF-170 (manufactured by Tohto Kasei Co., Ltd., trade name, epoxy equivalent = 170), 95 parts by mass Imidazole compound: 2PZ-CN (manufactured by Shikoku Kasei Co., Ltd., trade name), 5 parts by mass

The organic insulating film in which the metal body was impregnated with the curable resin composition was held in a nitrogen atmosphere at 150°C for 1 hour, resulting in a metal body-filled organic insulating film in which the resin filled the pores of the metal body and further cured.

Furthermore, the cured resin on the surface of the metal body was removed by reactive ion etching (RIE) under the conditions shown below to expose the metal body.
Device name: Plasma cleaning device (Sanyo High Technology, SPC-100B)
Power: 600W
Gas and flow rate: Ar, 5 SCCM
Processing time: 1 minute

Next, solder paste A was applied to one side of the metal body-filled organic insulating film by stencil printing using a metal squeegee to a thickness of 12 μm. After that, heat treatment was performed at 150°C for 10 minutes while flowing nitrogen gas at 50 mL/min, forming a resin layer (semi-cured resin) on one side of the organic insulating film. After the heat treatment, solder was formed on the metal body, and semi-cured resin was formed in the pores of the metal body.

Furthermore, the resin layer on the solder surface was removed by reactive ion etching (RIE) under the conditions shown below to expose the solder. The thickness of the resin layer after the surface was removed was 8 μm.
Device name: Plasma cleaning device (Sanyo High Technology, SPC-100B)
Power: 600W
Gas and flow rate: Ar, 5 SCCM
Processing time: 5 minutes

Next, in the same manner as above, a resin layer was formed on the other side of the metal body-filled organic insulating film, and solder was formed on the metal body. Next, in the same manner as above, the resin layer was removed to expose the solder.

<Second metal-containing part forming step>
Example 3
The PET film was peeled off from the metal-filled PET-attached organic insulating film, and the film was immersed in a water-soluble preflux treatment liquid "Tough Ace F2 (LX)" (product name, manufactured by Shikoku Chemical Industry Co., Ltd.) at 40°C for 60 seconds to remove the copper. After that, the film was immersed in a solder bath containing molten Sn42-Bi58 solder for 10 seconds to form solder on the surfaces (both end faces) of the metal bodies of the metal body-filled organic insulating film.

<Second metal-containing part forming step>
Example 4
The PET film was peeled off from the metal-filled PET-attached organic insulating film. The film was then immersed in a degreasing solution "Z-200" (manufactured by World Metal Co., Ltd., product name) at 50°C for 3 minutes and washed with water for 2 minutes. Then, the plate was immersed in a 100 g/l ammonium persulfate solution for 1 minute, rinsed with water for 2 minutes, immersed in 10% sulfuric acid for 1 minute, and rinsed with water for 2 minutes.

Next, the plate was immersed in "SA-100" (product name, manufactured by Hitachi Chemical Co., Ltd.), a plating activation treatment solution with a liquid temperature of 25°C, for 5 minutes, and then rinsed with water for 2 minutes. Next, the plate was immersed in "ICP Nicoron U" (product name, manufactured by Okuno Chemical Industries Co., Ltd.), an electroless nickel plating solution with a liquid temperature of 90°C, for 5 minutes, and then rinsed with water for 2 minutes.

Then, the film was immersed in a displacement gold plating solution "HGS-100" (product name, Hitachi Chemical Co., Ltd.) at a liquid temperature of 85°C for 10 minutes and then rinsed with water for 1 minute. This resulted in a metal body-filled organic insulating film in which a displacement gold plating film was formed on the electroless nickel plating film on the surface of the metal body (both end faces). After that, the film was immersed for 10 seconds in a solder bath containing molten Sn42-Bi58 solder to form solder on the surface of the displacement gold plating film of the metal body-filled organic insulating film.

<Second metal-containing part forming step>
(Examples 5 to 7)
Solder paste A containing solder particles and a curable resin composition having the following composition was applied to one side of the metal-filled organic insulating film by stencil printing using a metal squeegee to a thickness of 12 μm. Thereafter, a heat treatment was performed at 150° C. for 10 minutes while flowing nitrogen gas at 50 mL/min, to form a resin layer (semi-cured resin) on one side of the organic insulating film. Solder was formed in the holes of the metal body, and a semi-cured resin was formed in the holes of the metal body.
[Solder paste A]
Solder particles: Sn42-Bi58 particles (average particle size 20 μm), 70 parts by mass Bisphenol F type epoxy resin: YDF-170 (manufactured by Tohto Kasei Co., Ltd., product name, epoxy equivalent = 170), 25.2 parts by mass Imidazole compound: 2PZ -CN (trade name, manufactured by Shikoku Chemical Industry Co., Ltd.), 1.3 parts by mass 2,2-bishydroxymethylpropionic acid (BHPA), 3.5 parts by mass

Furthermore, the resin layer on the solder surface was removed by reactive ion etching (RIE) under the conditions shown below to expose the solder. The thickness of the resin layer after the surface was removed was 8 μm.
Device name: Plasma cleaning device (Sanyo High Technology, SPC-100B)
Power: 600W
Gas and flow rate: Ar, 5 SCCM
Processing time: 5 minutes

Next, the PET film was peeled off from the metal body-filled organic insulating film with PET on one side of which solder and a resin layer were formed. A resin layer was formed on the surface of the metal body-filled organic insulating film that had been in contact with the PET film in the same manner as described above, and solder was formed on the metal body. Next, the resin layer was removed in the same manner as described above, exposing the solder.

<Second metal-containing part forming step>
(Examples 8 to 10)
The PET film was peeled off from the metal-filled PET-attached organic insulating film, and the film was immersed in a water-soluble preflux treatment liquid "Tough Ace F2 (LX)" (product name, manufactured by Shikoku Chemical Industry Co., Ltd.) at 40°C for 60 seconds to remove the copper. After that, the film was immersed in a solder bath containing molten Sn42-Bi58 solder for 10 seconds to form solder on the surfaces (both end faces) of the metal bodies of the metal body-filled organic insulating film.

[Preparation of evaluation board]
As shown in (a) of Fig. 15, a polyimide film 95 with a copper circuit, in which a copper circuit electrode 94 is formed on the main surface of a polyimide film 93, and a polyimide film 98 with a copper circuit electrode 97 formed on a polyimide film 96, were arranged so that their circuit electrodes faced each other, and the anisotropic conductive member 70 obtained above was interposed between these electrodes. These were then bonded by applying pressure from above and below under conditions of 160°C, a pressure of 3 MPa, and 5 minutes in nitrogen. In this way, as shown in (b) of Fig. 15, an evaluation board 99 was obtained in which 30 through electrodes (10 through electrodes at both ends are shown in the figure, and through electrodes between them are omitted) that bond the electrode parts of the circuit were connected (the figure shows 10 through electrodes at both ends, and the through electrodes between them are omitted. The same is true for the polyimide film with a copper circuit).

[Initial resistance value]
The interconnection resistance was measured as the initial resistance of the evaluation board connected by the anisotropic conductive member. The resistance of 30 through electrodes was measured. The measured interconnection resistance was evaluated according to the following criteria. Evaluations of B or higher were judged to be good. The results are shown in Table 1.
A: Resistance value is less than 10 mΩ B: Resistance value is 10 mΩ or more but less than 30 mΩ C: Resistance value is 30 mΩ or more but less than 100 mΩ D: Resistance value is 100 mΩ or more but less than 500 mΩ E: Resistance value is 500 mΩ or more

[Resistance value after bending test-1]
The evaluation boards connected by the anisotropic conductive member were wrapped around a rod with a diameter of 0.8 cm and held in the air for 1 minute, after which the linked connection resistance value was measured. The resistance value of 30 through electrodes connected together was measured. The measured linked connection resistance value was evaluated according to the following criteria. A rating of B or higher was judged to be good. The results are shown in Table 1.
A: Resistance value is less than 10 mΩ B: Resistance value is 10 mΩ or more but less than 30 mΩ C: Resistance value is 30 mΩ or more but less than 100 mΩ D: Resistance value is 100 mΩ or more but less than 500 mΩ E: Resistance value is 500 mΩ or more

[Resistance value after bending test-2]
The evaluation boards connected by the anisotropic conductive member were wrapped around a rod with a diameter of 1 cm and held in the air for 1 minute, after which the linked connection resistance was measured. The resistance value of 30 through electrodes connected together was measured. The measured linked connection resistance value was evaluated according to the following criteria. A rating of B or higher was judged to be good. The results are shown in Table 1.
A: Resistance value is less than 10 mΩ B: Resistance value is 10 mΩ or more but less than 30 mΩ C: Resistance value is 30 mΩ or more but less than 100 mΩ D: Resistance value is 100 mΩ or more but less than 500 mΩ E: Resistance value is 500 mΩ or more

[Temperature cycle connection reliability test]
The evaluation boards connected by the anisotropic conductive member were set in a temperature cycle tester (TSA-72SE-W, manufactured by Espec Corporation), and a temperature cycle connection reliability test was performed under the following conditions: low temperature side: -40°C, 15 minutes, room temperature: 2 minutes, high temperature side: 125°C, 15 minutes, defrost cycle: automatic, number of cycles: 50, 100, 300, 500 cycles. The resistance value of 30 through holes connected together was measured. The measured connected connection resistance value was evaluated according to the following criteria. Those that were evaluated as B or higher after 500 temperature cycle tests were judged to be good. The results are shown in Table 1.
A: The rate of resistance change is less than 1% of the initial resistance value. B: The rate of resistance change is 1% or more and less than 3% of the initial resistance value. C: The rate of resistance change is 3% or more and less than 5% of the initial resistance value. D: The rate of resistance change is 5% or more and less than 10% of the initial resistance value. E: The rate of resistance change is 10% or more and less than 20% of the initial resistance value. F: The rate of resistance change is 20% or more of the initial resistance value.

[Measurement of porosity of metal body]
(Examples 1 to 10)
For the organic insulating film with metal body-filled PET obtained in the metal body forming step, a focused ion beam processing observation device (manufactured by Hitachi High-Technologies Corporation, product name: MI4050) was used to expose the cross section of the center of the through hole of the organic insulating film filled with the metal body and the cross section of the metal body provided on the main surface of the organic insulating film by the focused ion beam, and the cross section was observed. When observing the cross section of the center of the through hole, a range of ±5 μm from the center of the metal body filled in the through hole in the thickness direction of the organic insulating film and ±5 μm in the direction perpendicular to the thickness direction of the organic insulating film was observed. When observing the cross section of the metal body provided on the main surface of the organic insulating film, a range of 10 μm in the thickness direction of the organic insulating film and 10 μm in the direction perpendicular to the thickness direction of the organic insulating film was observed in the region up to 5 μm from the surface of the metal body formed on the main surface of the organic insulating film.

A scanning electron microscope (Hitachi High-Technologies Corporation, product name: S-3700N) was used for the observations at a magnification of 10,000 times to take cross-sectional images (approximately 10 μm square) of the metal body. Five observation locations were used. The cross-sectional images obtained were binarized using image analysis software (Adobe Photoshop (registered trademark) Elements) so that the metal and porous portions could be separated. For each of the five observation locations, the ratio of the area of the porous portion to the total area of the cross section of the metal body was taken as the porosity. The average porosity of the five observation locations was taken as the porosity of the metal body. The results are shown in Table 1.

[Filling rate of cured resin in conductor]
(Examples 1, 2, 5 to 6)
The anisotropic conductive member obtained above was mechanically polished and cut in the thickness direction of the organic insulating film, and the cross section of the center of the through hole of the organic insulating film was exposed by a focused ion beam, and these cross sections were observed. When observing the cross section of the center of the through hole of the organic insulating film, a range of ±5 μm from the center of the through hole in the thickness direction of the organic insulating film and ±5 μm in the direction perpendicular to the thickness direction of the organic insulating film was observed. A focused ion beam processing observation device (manufactured by Hitachi High-Technologies Corporation, product name: MI4050) was used. For the observation, a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, product name: S-3700N) was used with a magnification of 10,000 times to take a cross-sectional image (about 10 μm square) of the conductor. Five observation points were observed. The obtained cross-sectional image was binarized using image analysis software (Adobe Photoshop (registered trademark) Elements) so that the metal part and the cured resin part were separated from the space in the porous part that was not filled with the cured resin. For each of the five observation points, the ratio of the area of the space in the porous part that was not filled with the cured resin to the total area of the cross section of the conductor was determined, and this was taken as the porosity. The average value of the porosity of the five observation points was taken as the porosity of the conductor. The porosity of the metal body and the porosity of the conductor were substituted into the following formula (1) to calculate the filling rate of the cured resin in the conductor.
Filling rate (%) of cured resin in conductor=[(B−A)/B]×100 Equation (1)
[In formula (1), A represents the porosity (%) of the conductor, and B represents the porosity (%) of the metal body.]

Reference Signs List 1...organic insulating film, 2...metal coating, 3...metal particle composition, 4...hole (porous, void), 5...metal body, 6...resin cured product, 8...etching resist, 9...wiring, 10...conductive member (organic insulating film filled with metal body), 12...copper sintered body, 14...solder, 30...through hole, 35...conductor, 40...organic insulating film with metal coating formed thereon, 41...organic insulating film, 42, 43, 44, 46, 47, 70, 72...conductive member, 45...substrate, 48, 49... Coated body, 50...metal body-filled organic insulating film, 51, 52...substrate having through electrodes, 60...solder-containing portion, 61...electroless plating coating, 62...resin cured product, 63...solder particles, 64...curable resin composition, 67, 69...resin layer, 90...semiconductor chip, 91...semiconductor package, 92...semiconductor device, 93, 96...polyimide film, 94, 97...copper circuit electrode, 95, 98...polyimide film with copper circuit, 99...evaluation board, A...pressure jig

Claims (30)

The insulating film has an organic insulating film and a conductive portion penetrating the organic insulating film in a thickness direction.
The conductive portion includes a metal body having a porous structure,
The metal body contains a copper sintered body having a porous structure ,
The copper sintered body is a sintered body of a metal particle composition including flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, and second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less,
A conductive member , wherein the metal body contains discretely distributed solder . The conductive member of claim 1 , wherein the solder comprises tin or a tin alloy. 2. The conductive member according to claim 1 , wherein the solder is In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or a Sn--Cu based alloy. The conductive member according to any one of claims 1 to 3 , wherein the porosity of the metal body is 1 to 15 volume % based on the volume of the metal body. The conductive member according to claim 1 , wherein the conductive portion further comprises a cured resin or a semi-cured resin present in the pores of the metal body. The conductive member according to claim 5 , wherein the content of the cured resin in the conductive portion is 80 volume % or more based on the total volume of the internal spaces of the pores of the metal body. the metal body is provided so as to penetrate the organic insulating film in a thickness direction,
The conductive member according to claim 1 , wherein the conductive portion includes a solder-containing portion provided so as to cover at least a portion of one end or both ends of the metal body. The conductive member of claim 7 , wherein the solder-containing portion comprises tin or a tin alloy. 8. The conductive member according to claim 7 , wherein the solder-containing portion is In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or a Sn--Cu based alloy. the metal body is provided so as to penetrate the organic insulating film in a thickness direction,
The conductive member according to claim 1 , wherein the conductive portion includes an electroless plating film provided so as to cover at least a portion of one end or both ends of the metal body. the metal body is provided so as to penetrate the organic insulating film in a thickness direction,
The conductive portion includes an electroless plating film provided so as to cover at least a portion of one end or both ends of the metal body, and a solder-containing portion provided so as to cover the electroless plating film.
The conductive member according to any one of claims 1 to 6 . The conductive member of claim 11 , wherein the solder-containing portion comprises tin or a tin alloy. 12. The conductive member according to claim 11 , wherein the solder-containing portion is In--Sn, In--Sn--Ag, Sn--Bi, Sn--Bi--Ag, Sn--Ag--Cu, or a Sn--Cu based alloy. The conductive member according to any one of claims 1 to 13 , wherein the organic insulating film has a thickness of 1 to 50 µm. The conductive member according to any one of claims 1 to 14 , wherein the organic insulating film comprises a cured product of a photosensitive insulating film. A semiconductor device having a connection structure in which a semiconductor chip and a support member for mounting a semiconductor chip are electrically connected to each other via the conductive member according to any one of claims 1 to 15 , and/or a connection structure in which a plurality of semiconductor chips are electrically connected to each other via the conductive member according to any one of claims 1 to 15 . a preparation step of preparing a substrate including an organic insulating film having through-holes, the through-holes communicating with both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure so as to fill at least the through hole,
The metal body forming step includes a filling step of filling the through holes of the base with a metal particle composition containing copper particles;
and a firing step of firing the metal particle composition to form the metal body ,
A method for producing a conductive member, wherein the metal particle composition comprises flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less, and solder particles . The conductor forming step includes:
a resin impregnation step of impregnating the metal body with a curable resin composition;
a resin curing step of curing the curable resin composition impregnated in the metal body;
The method for producing a conductive member according to claim 17 , further comprising: a preparation step of preparing a substrate including an organic insulating film having through-holes, the through-holes communicating with both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure so as to fill at least the through hole,
The metal body forming step includes a filling step of filling the through holes of the base with a metal particle composition containing copper particles;
and a firing step of firing the metal particle composition to form the metal body ,
The metal particle composition includes flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, and second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less,
The conductor forming step includes:
a resin impregnation step of impregnating the metal body with a curable resin composition;
a resin curing step of curing the curable resin composition impregnated in the metal body;
The method for producing a conductive member comprising the steps of : The method for producing a conductive member according to any one of claims 17 to 19, wherein the metal particle composition does not contain a curable resin component or contains a curable resin component in an amount of 4 mass% or less based on the total amount of the composition. The method for producing a conductive member according to claim 17 , further comprising a conductor removing step of removing at least a portion of the conductor formed on the main surface of the base. A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes a step of immersing the organic insulating film on which the metal body is formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the metal body is formed and heating the solder composition ;
A method for producing a conductive member, wherein the metal particle composition comprises flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less, and solder particles . A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes a step of immersing the organic insulating film on which the metal body is formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the metal body is formed and heating the solder composition ;
The metal particle composition includes flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, and second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less,
A method for manufacturing a conductive member, wherein the conductor forming process includes, between the metal body forming process and the second metal-containing portion forming process, a resin impregnation process of impregnating the metal body with a curable resin composition, and a resin curing process of curing the curable resin composition impregnated into the metal body . A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes an electroless plating step of forming an electroless plating film so as to cover at least a portion of one end or both ends of the metal body, and a step of immersing the organic insulating film on which the electroless plating film has been formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the electroless plating film has been formed and heating the solder composition;
A method for producing a conductive member, wherein the metal particle composition comprises flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less, and solder particles . A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes an electroless plating step of forming an electroless plating film so as to cover at least a portion of one end or both ends of the metal body, and a step of immersing the organic insulating film on which the electroless plating film has been formed in a bath containing molten solder, or a step of placing a solder composition on the organic insulating film on which the electroless plating film has been formed and heating the solder composition;
The metal particle composition includes flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, and second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less,
A method for manufacturing a conductive member, wherein the conductor forming process includes, between the metal body forming process and the second metal-containing portion forming process, a resin impregnation process of impregnating the metal body with a curable resin composition, and a resin curing process of curing the curable resin composition impregnated into the metal body . The method for manufacturing a conductive member according to any one of claims 22 to 25, wherein the conductor forming process includes, between the metal body forming process and the second metal-containing portion forming process, a resin impregnation process of impregnating the metal body with a curable resin composition, and a resin curing process of curing the curable resin composition impregnated into the metal body. A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes a step of applying a solder paste containing solder particles and a curable resin composition onto one or both main surfaces of the organic insulating film on which the metal body is formed, and a step of heating the applied solder paste ;
A method for producing a conductive member, wherein the metal particle composition comprises flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less, and solder particles . A preparation step of preparing an organic insulating film having through holes extending to both main surfaces;
and forming a conductor in the through hole,
the conductor forming step includes a metal body forming step of forming a metal body having a porous structure in the through hole, and a second metal-containing portion forming step of forming a second metal portion that covers at least a portion of one end or both ends of the metal body,
the metal body forming step includes a filling step of filling the through-holes of the organic insulating film with a metal particle composition containing copper particles, and a firing step of firing the metal particle composition to form the metal body,
the second metal-containing portion forming step includes a step of applying a solder paste containing solder particles and a curable resin composition onto one or both main surfaces of the organic insulating film on which the metal body is formed, and a step of heating the applied solder paste ;
The metal particle composition includes flat first copper particles having an average particle size of 0.8 μm or more and 10 μm or less, and second copper particles having an average particle size of 0.01 μm or more and 0.5 μm or less,
A method for manufacturing a conductive member, wherein the conductor forming process includes, between the metal body forming process and the second metal-containing portion forming process, a resin impregnation process of impregnating the metal body with a curable resin composition, and a resin curing process of curing the curable resin composition impregnated into the metal body . The method for producing a conductive member according to claim 22 , wherein the preparation step comprises exposing and developing a photosensitive insulating film to produce the organic insulating film. 30. The method of claim 23, 25, or 28 , wherein the metal particle composition further comprises solder particles.

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