JP7837038B2 - copper component - Google Patents

Description

This invention relates to a copper component.

Multilayer wiring boards have a structure in which insulating layers and wiring layers are alternately repeated. Therefore, during the manufacturing process of multilayer boards, adhesion between the wiring surface and the insulating layer is imparted. For this purpose, the following processing methods have conventionally been used.

The blackening treatment method involves applying fine, needle-shaped copper oxide crystals to the surface of the wiring, thereby achieving adhesion between the wiring and the insulating layer through an anchoring effect.

Another method involves imparting fine needle-shaped crystals of metallic copper to the wiring surface, thereby achieving adhesion between the wiring and the insulating layer through an anchoring effect. For example, Patent Document 1 describes a method of imparting micron-order roughening to the wiring surface, thereby achieving adhesion between the wiring and the insulating material through an anchoring effect. Patent Document 2 discloses a surface treatment method that improves the adhesion strength between the interlayer insulating layer and the wiring without forming irregularities on the wiring surface that would create an anchoring effect. This method involves oxidizing copper to form copper oxide, then treating it with an alkali silicate solution, and finally applying a silane coupling agent. Patent Document 3 discloses a method of forming a compound having Si-O-Si bonds on the wiring surface, and then forming a treatment film containing a coupling agent or adhesion improver on top of it. Patent Document 4 discloses a copper surface treatment method comprising the step of forming a metal layer on the copper surface and treating it with a solution containing at least one of alkali silicate, silicate ester, polysilazane, or a bifunctional silane compound.

Japanese Patent Publication No. 2000-282265 Japanese Patent Publication No. 2002-069661 Japanese Patent Publication No. 2006-080203 Japanese Patent Publication No. 2007-107080

This invention provides a novel copper component.

One embodiment of the present invention is a copper component in which a Si compound is detected by elemental analysis of the surface by time-of-flight secondary ion mass spectrometry (TOF-SIMS), and in waveform separation of the O1s spectrum of the surface by X-ray photoelectron spectroscopy (XPS), the value of (area percentage of the peak area of the Cu compound) / (area percentage of the peak area of SiO) is greater than 1.0 and less than 15.0, and the Cu compound contains copper oxide.

Another embodiment of the present invention is a copper member in which a Si compound is detected by elemental analysis of the surface by TOF-SIMS, and the amount of Si detected by elemental analysis of the surface by inductively coupled plasma emission spectroscopy (ICP-AES) is ¹⁰ μg/dm² or more and less than 150 μg/ ^dm² , and the value of (sum of film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by Sequential Electrochemical Reduction Analysis (SERA)) / (mass of Si per unit area measured by ICP-AES) is greater than 0.5 and less than 10.

Any of the Si compounds may be detected within 1 nm of the surface.

A further embodiment of the present invention is a copper member wherein, in the waveform separation of the _O1S spectrum of the surface by XPS, the area percentage of the peak area of SiO is 2 Area % or more, and in the waveform separation of the O1S spectrum of the surface by XPS, the value of (area percentage of the peak area of the Cu compound) / (area percentage of the peak area of SiO) is greater than 1.0 and less than 15.0, and the Cu compound contains copper oxide.

A further embodiment of the present invention is a copper member wherein, in the waveform separation of the O1s spectrum of the surface by XPS, the area percentage of the peak area of SiO is 2 Area % or more, the amount of Si detected on the surface by elemental analysis of the surface by ICP-AES is ¹⁰ μg/dm² or more and less than 150 μg/ ^dm² , and the value of (sum of film thickness of _Cu₂O , CuO, and _Cu₂S measured by SERA) / (mass of Si per unit area measured by ICP-AES) is greater than 0.5 and less than 10.

In any of the above copper members, the total thickness of the _Cu₂O , CuO, and _Cu₂S layers detected on the surface by elemental analysis of the surface using SERA may be 20 nm or more. On the surface, the atomic percentage of N₁s to the total number of N₁s, Na₁s, Si₂p, and Cu₂p₃ atoms in the XPS Narrow spectrum may be 0.5 at% or more. On the surface, the atomic percentage of Na₁s to the total number of N₁s, Na₁s, Si₂p, and Cu₂p₃ atoms in the XPS Narrow spectrum may be 0.1 at% or less. The Rz of the surface may be 0.39 μm or more.

A further embodiment of the present invention is a method for manufacturing any of the above-mentioned copper components using a copper material, comprising: a first step of oxidizing the copper material; a second step of treating the copper material oxidized in the first step with a coupling agent; and a third step of treating the copper material oxidized in the first step with water glass. The second step may be performed before, after, or before/after the third step.

A further embodiment of the present invention is a method for manufacturing any of the above-mentioned copper components using a copper material, comprising a first step of oxidizing the copper material, and a fourth step of treating the copper material oxidized in the first step with water glass containing a coupling agent. A fifth step of treating the copper material oxidized in the first step with a coupling agent may also be included. The fourth step may be performed before, after, or before/after the fifth step.

In any of the above methods, the coupling agent may be one or more selected from the group consisting of 3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-ureidopropyltrialkoxysilane, and 3-acryloxypropyltrimethoxysilane.

A further embodiment of the present invention is a laminate in which a resin substrate is laminated on the surface of any of the above-described copper members.

A further embodiment of the present invention is a printed circuit board including the above-described laminate.

This invention provides a novel copper component.

This figure shows the analysis results of each copper component by TOF-SIMS in an embodiment of the present invention.

The following describes preferred embodiments of the present invention in detail with reference to the accompanying drawings, but the invention is not necessarily limited thereto. The object, features, advantages, and ideas of the present invention will be apparent to those skilled in the art from the description herein, and those skilled in the art will be able to easily reproduce the present invention from the description herein. The embodiments and specific examples of the invention described below are examples of preferred embodiments of the present invention and are provided for illustrative or explanatory purposes only; the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and modifications can be made based on the description herein, within the intent and scope of the present invention as disclosed herein.

==Copper Components==
(1) Si compound layer The copper surface of the copper member disclosed herein has a Si compound layer. The Si compound layer contains silicon oxide (SixOy) and/or silicon hydroxide (SixOyHz), or the Si compound layer consists of silicon oxide (SixOy) and/or silicon hydroxide (SixOyHz). Examples of silicon oxide and silicon hydroxide include SiO, _SiO₂ , _SiO₄ , _SiO₄H₄ , _{Si₂O ₷ H₆} , _{SiO₃H₂ , and Si₂O₅H₂ .} In addition to silicon oxide and _silicon hydroxide, the Si compound layer may also contain silicon carbides, sulfides, nitrides, halides, or silicides of metallic elements. Elemental analysis of the copper surface of a copper component by time-of-flight secondary ion mass spectrometry (TOF-SIMS) or X-ray photoelectron spectroscopy (XPS) reveals the presence of silicon dioxide (SixOy) and silicon hydroxide (SixOyHz) (collectively referred to as Si compounds in this specification). The Si and its compounds content in Si2p obtained by XPS is preferably 0.5% or more, more preferably 1% or more, and even more preferably 3% or more, relative to the total number of elemental elements and their compounds contained in N1s, Na1s, Si2p, and Cu2p3. In elemental analysis by XPS, it is preferable that the area percentage of the peak area of SiO relative to the peak area of all molecules is 2Area% or more when the O1s spectrum of the copper surface of the copper component is waveform-separated. (Hereafter, when waveform separation is performed in XPS, the area percentage of the peak area of a given molecule will represent the ratio of the peak area of that molecule to the peak area of all molecules, unless otherwise specified.) Typically, TOF-SIMS analyzes molecules within 1 nm of the surface, while XPS analyzes molecules within a few nm to tens of nm of the surface (for example, within 10 nm or 20 nm). To that extent, the analytical conditions are not particularly limited and can be appropriately determined by those skilled in the art.

This copper component satisfies at least one of the following conditions [1] and [2]. This improves the acid resistance and adhesion when the copper component is bonded to the resin.

[1] When the O1s spectrum of the copper member surface is waveform-separated by XPS, the value of (area percentage of peak area of Cu compound) / (area percentage of peak area of SiO) is greater than 1.0 and less than 15.0. Preferably, it is 1.2 or more and 14.2 or less, and more preferably 2.9 or more and 7.3 or less. In this specification, Cu compound is a general term for CuO, _Cu₂O , Cu(OH) _₂ , and _CuCO₃ .

[2] The amount of Si detected by inductively coupled plasma emission spectroscopy (ICP-AES) is 10 μg/ ^dm² or more and 150 μg/dm² or ^less , and the value of (sum of film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by Sequential Electrochemical Reduction Analysis (SERA)) / (mass of Si per unit area measured by ICP-AES) is greater than 0.5 and less than 10. The amount of Si is preferably 10 μg/dm² or ^more and 150 μg/dm² or less, more preferably 10 μg/dm² or ^more and 140 μg/ ^dm² or ^less , and even more preferably 42.5 μg/dm² or ^more and 47.6 μg/ ^dm² or less. The value of (sum of the film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by SERA) / (mass of Si per unit area measured by ICP-AES) is preferably greater than 0.5 and less than 10, more preferably between 0.6 and 7.5, and even more preferably between 0.7 and 3.3. The Cu compound is present on the protrusions of the surface, and SiO is the protective layer portion. Therefore, a small value of this ratio indicates that the protective layer is thin relative to the surface irregularities, while a large value indicates that the protective layer is thick. However, when the value is within the above range, the protective layer has an appropriate thickness relative to the surface irregularities. In this specification, "film thickness" of _Cu₂O , CuO, and _Cu₂S refers to the distance each exists in a direction perpendicular to the surface (i.e., the length from the point closest to the surface to the point furthest from the surface, along an axis perpendicular to the surface) when they are spread out on or near the surface of the copper member. The "film thickness" may be calculated by measuring at multiple points and averaging them. Therefore, the individual films may overlap, in which case the sum of the film thicknesses of _Cu₂O , CuO, and _Cu₂S will be greater than the film thickness of the Cu compound.

While not strictly adhering to the following principles, if there is a greater proportion of Cu compounds compared to Si compounds, the amount of Si compound adhering to the copper component surface will be small, resulting in insufficient protection of the Cu compound and poor acid resistance. Conversely, if there is a greater proportion of Si compounds compared to Cu compounds, the amount of Si compound adhering will be excessive, filling in the irregularities formed by the Cu compound and reducing the surface area, thus preventing excellent adhesion. As shown in [1], both excellent acid resistance and excellent adhesion can be obtained when the balance between Cu and Si compounds is appropriate. Furthermore, if the total thickness of the _Cu₂O , CuO, and _Cu₂S film is too small, the surface irregularities formed by _Cu₂O , CuO, and _Cu₂S will be insufficient, resulting in poor adhesion. Conversely, if the total thickness is too large, the surface irregularities will be too long, resulting in insufficient Si compound protection and poor acid resistance, or the irregularities may be cut midway, resulting in poor adhesion. The parameters in [2] can also serve as indicators of the balance between Si and Cu compounds.

The copper component preferably has a total film thickness of _Cu₂O , CuO, _{and Cu₂S} detected by SERA of 20 nm or more and 300 nm or less, preferably 35 nm or more and 300 nm or less, and more preferably 35 nm or more and 139 nm or less.

The height of the protrusions on the surface of the copper member is preferably 50 nm or more, more preferably 100 nm or more, and even more preferably 150 nm or more. Furthermore, it is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. The height of the protrusions can be measured, for example, by taking a cross-sectional image with a scanning electron microscope (SEM), taking multiple points at predetermined intervals, measuring the length from each point to the highest point of the nearest protrusion perpendicular to the processed surface, and calculating the average value.

Furthermore, the unfolded area ratio (Sdr) on the surface of the copper member is preferably 4% or more, more preferably 5% or more, and even more preferably 10% or more. Sdr can be measured, for example, by a confocal scanning electron microscope (CSEM).

While we are not strictly bound by the following principles, as mentioned above, if the total thickness of the _Cu₂O , CuO, and _Cu₂S film is too small, the surface irregularities formed by _Cu₂O , CuO, and _Cu₂S will be insufficient, resulting in poor adhesion. Conversely, if the total thickness is too large, the surface irregularities will be too long, resulting in insufficient Si compound, poor acid resistance, or the irregularities may break midway, leading to poor adhesion. Note that the height of the irregularities and Sdr in SEM are parameters that show a similar trend to the total film thickness.

Furthermore, a surface roughness (Rz) measured by CSEM is preferably 0.39 μm or higher, and more preferably 0.89 μm or higher. If the surface roughness is too low, the surface irregularities are small, and adhesion cannot be obtained.

In the outermost surface narrow spectrum measured by XPS, the atomic percentage of Si2p atoms relative to the sum of the atomic numbers of the four components N1s, Na1s, Si2p, and Cu2p3 is preferably 3.0 Atm% to 45.0 Atm%, more preferably 4.1 Atm% to 36.3 Atm%, and even more preferably 4.1% to 12.3%. If the atomic percentage of Si2p is high, the amount of Si compound adhering to the surface is too large, reducing surface roughness and decreasing adhesion. Conversely, if the atomic percentage of Si2p is low, the surface roughness is not sufficiently covered by the Si compound, resulting in reduced acid resistance.

When the O1s spectrum of the copper member surface is waveform-separated by XPS, the area percentage of the peak area of Cu(OH) _₂ relative to the total peak areas of CuO, _Cu₂O , and Cu(OH) _₂ is preferably 70 Area % or less, more preferably 45 Area % or less, and even more preferably 40 Area % or less. If there is a large amount of Cu(OH) _₂ , it is thought that many functional groups that are not bonded to Si remain, in which case the adhesion is poor.

Furthermore, alkali metals can corrode copper components and increase transmission loss, so a low alkali metal content is preferable. For example, the alkali metal content obtained by analyzing the surface of a copper component using XPS is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less, when the sum of the atomic percentages of N1s, Na1s, Si2p, and Cu2p3 atoms is taken as 100%.

(2) Copper Oxide Layer The copper member may have a layer containing copper oxide or a layer made of copper oxide (collectively referred to as a copper oxide layer in this specification) inside the Si compound layer. This allows for strong adhesion to the insulating material. Here, the copper oxide contains copper oxide (CuO) and/or cuprous oxide ( _Cu₂O ), or consists of copper oxide (CuO) and/or cuprous oxide ( _Cu₂O ). The copper oxide content in the copper oxide layer is preferably 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. The copper oxide layer may also contain copper hydroxide (Cu(OH) _₂ ), and its content is preferably 3% by weight or more, 5% by weight or more, 10% by weight or more, or 15% by weight or more. Copper hydroxide is thought to undergo dehydration condensation with the Si compound, and if the amount of copper hydroxide is small, it will not bond sufficiently with the Si compound, resulting in reduced acid resistance and adhesion. In this specification, the term "copper component" is used to include copper components that have copper oxide.

The thickness of the copper oxide layer is preferably 500 nm or less on average, more preferably 300 nm or less on average, even more preferably 200 nm or less on average, even more preferably 160 nm or less on average, and even more preferably 90 nm or less on average. Furthermore, the thickness of the copper oxide layer is preferably 20 nm or more on average, more preferably 30 nm or more on average, and even more preferably 40 nm or more on average. The proportion of the region where the copper oxide layer thickness is 500 nm or less is not particularly limited, but it is preferably 50% or more is 500 nm or less, more preferably 70% or more is 500 nm or less, even more preferably 90% or more is 500 nm or less, even more preferably 95% or more is 500 nm or less, and even more preferably 99% or more is 500 nm or less. The thickness of the copper oxide layer can be calculated, for example, by SERA at 10 measurement points in an area of 10 × 10 cm.

If the copper oxide layer is too thin, the surface irregularities will be insufficient, or the irregularities will be easily filled in by the Si compound, resulting in poor adhesion. Conversely, if the copper oxide layer is too thick, the surface protrusions will be too long, making it difficult for the Si compound to adequately cover the surface, or the protrusions may be cut off midway, again resulting in poor adhesion. The thickness of the copper oxide layer on the surface of the copper component is a parameter that shows a similar trend to the height of the protrusions and Sdr.

(3) Use of copper members The copper members according to the present invention can be suitably used as members that require high acid resistance and high adhesion to resins. For example, they can be suitably used in copper wiring, copper pillars, lead frames, etc. of printed circuit boards that include laminates in which a resin substrate is laminated on the copper surface.

==Manufacturing Method for Copper Components==
An embodiment of the manufacturing method for the copper component described above is described below.

(1) Preparation of copper material Prepare a copper material, which is the material for the copper component, in which part or all of the surface is covered with copper. The copper material only needs to have copper on its surface, and the part inside the copper surface (i.e., the interior of the copper material) may be a substance other than copper, or a metal other than copper, but the interior of the copper material may also be copper, and the entire copper material may be made of copper. If the interior of the copper material is made of a substance different from the copper on the surface, the thickness of the copper on the surface is preferably more than 1 nm, but may be 10 nm or more, or 100 nm or more. The copper on the surface may be formed by plating. When the copper on the surface is formed by copper plating, the thickness of the copper film by plating is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less, and more preferably 0.5 μm or more and 50 μm or less.

The surface copper is preferably made of pure copper with a purity of 95% by mass or more, 99% by mass or more, or 99.9% by mass or more. It is more preferably formed from tough pitch copper, deoxidized copper, or oxygen-free copper, and even more preferably from oxygen-free copper with an oxygen content of 0.001% to 0.0005% by mass.

The copper materials disclosed herein include, but are not limited to, copper foils such as electrolytic copper foil, rolled copper foil, and copper foil with carriers, copper wires, copper plates, copper lead frames, copper powder, copper heat sinks, copper pillars, and copper-plated objects. Among these, copper foil or copper plates are preferred. In the case of copper foil, its thickness is 0.1 μm or more and 100 μm or less. Particularly preferred is a thickness of 0.5 μm or more and 50 μm or less. In the case of copper plates, a plate-like material with a thickness exceeding 100 μm is preferred, with thicknesses of 0.5 mm or more, 1 mm or more, 2 mm or more, or 10 mm or more, and lengths of 10 cm or less, 5 cm or less, or 2.5 cm or less being preferred.

(2) Oxidation treatment First, the copper material surface is oxidized to form a copper oxide layer on the copper material surface. This oxidation treatment roughens the copper material surface, increasing its adhesion to the resin.

Prior to this oxidation treatment, a surface roughening process such as soft etching or etching may be performed. Alternatively, prior to the oxidation treatment, degreasing, acid cleaning to homogenize the surface by removing the natural oxide film, or alkaline treatment after acid cleaning to prevent the introduction of acid into the oxidation process may be performed. The method of alkaline treatment is not particularly limited, but preferably, an alkaline aqueous solution of 0.1 to 10 g/L, more preferably 1 to 2 g/L, such as an aqueous sodium hydroxide solution, should be used, and the treatment should be performed at 30 to 50°C for about 0.5 to 2 minutes.

The oxidation treatment method is not particularly limited, but it may be formed using an oxidizing agent, or by heat treatment or anodic oxidation.

The oxidizing agent is not particularly limited, and for example, aqueous solutions of sodium chlorite, sodium hypochlorite, potassium chlorate, potassium perchlorate, etc. can be used. Various additives (for example, phosphates such as trisodium phosphate dodecahydrate) and surface-active molecules may be added to the oxidizing agent. As surface-active molecules, porphyrin, macro-ring porphyrin, expanded porphyrin, ring-contracted porphyrin, linear porphyrin polymer, porphyrin sandwich coordination complex, porphyrin sequence, silane, tetraorgano-silane, aminoethyl-aminopropyltrimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea) ((l-[3-(Trimethoxysilyl)propyl]urea)), (3-aminopropyl)triethoxysilane, ((3-glycidyloxypropyl)trimethoxysilane Examples include (lanes), (3-chloropropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, ethylene-trimethoxysilane, amines, sugars, etc.

Various additives (for example, phosphates such as trisodium phosphate dodecahydrate) or surface-active molecules may be added to the oxidizing agent to adjust the precipitation of copper oxides. Examples of surface-active molecules include porphyrin, macro-ring porphyrin, expanded porphyrin, ring-contracted porphyrin, linear porphyrin polymer, porphyrin sandwich coordination complex, porphyrin sequence, silane, tetraorgano-silane, aminoethyl-aminopropyl-trimethoxysilane, 3-aminopropyl)trimethoxysilane, 1-[3-(trimethoxysilyl)propyl]urea, (3-aminopropyl)triethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, and (3-chloropropyl)trimethoxy Examples include silanes, (3-glycidyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, ethylene-trimethoxysilane, amines, and sugars.

The oxidation reaction conditions are not particularly limited, but the liquid temperature of the oxidizing agent is preferably 40 to 95°C, and more preferably 45 to 80°C. The reaction time is preferably 0.5 to 30 minutes, and more preferably 1 to 10 minutes.

The copper oxide layer may be prepared by using a solvent to adjust the protrusions on the surface of the oxidized copper material. The solvent used in this dissolution step is not particularly limited, but it is preferably a chelating agent, especially a biodegradable chelating agent. Examples include ethylenediaminetetraacetic acid, diethanolglycine, L-glutamic acid diacetate tetrasodium, ethylenediamine-N,N'-disuccinic acid, 3-hydroxy-2,2'-iminodisuccinate sodium, methylglycine diacetate trisodium, aspartate diacetate tetrasodium, N-(2-hydroxyethyl)iminodiacetate disodium, and sodium gluconate. The pH of the solvent solution is not particularly limited, but it is preferably alkaline, more preferably pH 8 to 10.5, even more preferably pH 9.0 to 10.5, and still more preferably pH 9.8 to 10.2.

The surface of this copper oxide layer may be reduced using a reducing agent, in which case cuprous oxide may be formed on the surface of the layer containing the copper oxide. Examples of reducing agents used in this reduction process include dimethylamine borane (DMAB), diborane, sodium borohydride, and hydrazine.

While pure copper has a resistivity of 1.7 × ^10⁻⁸ (Ωm), copper oxide has a resistivity of 1 to 10 (Ωm), and cuprous oxide has a resistivity of 1 × ^10⁶ to 1 × ^10⁷ (Ωm). Therefore, layers containing copper oxide have low conductivity, and even if a large amount of the copper oxide layer transferred to the resin substrate is present, transmission loss due to the skin effect is less likely to occur when forming circuits for printed circuit boards or semiconductor package substrates using the copper component according to the present invention.

(3) Water Glass Treatment The method for manufacturing copper components includes a step of forming a Si compound on an oxidized copper material. The method for forming the Si compound is not particularly limited, but when processing with a liquid, water glass treatment is preferred. Through this treatment, the OH groups of Cu(OH) ₂ contained in the copper oxide layer bond with the water glass, enhancing the acid resistance of the copper component in bonding with the resin. However, if the amount of Cu(OH) ₂ contained in the copper oxide is small, a small amount of water glass will not be able to cover the surface of the copper component. Therefore, a large amount of water glass will be required. Also, if the Si compound layer becomes thick, the surface of the copper component becomes smoother and the surface area decreases, reducing adhesion to the resin. However, if the amount of water glass is insufficient, the surface of the copper component cannot be completely covered, and sufficient acid resistance cannot be obtained. Therefore, water glass treatment with an appropriate balance with the oxidation treatment is required.

The water glass used for treating copper materials is an aqueous solution of alkali metal silicate. Alkali metal silicate is represented by the formula _M₂O・_nSiO₂ (where M is Na, Li, or K), and _M₂O and _SiO₂ are present in various proportions in the water glass. The water glass used for treating copper materials is not particularly limited, but it is preferable that n is between 2 and 4.

The specific method of water glass treatment is not particularly limited. The water glass may be applied to the copper material surface by roller or bar coater, sprayed, or the copper material may be immersed in water glass. The concentration of _M₂O・_nSiO₂ in the water glass is not particularly limited, but may be 0.1% to 20%, 0.5% to 10%, or 2% to 5%. The reaction conditions are not particularly limited, but the treatment temperature is preferably 10°C to 95°C, and more preferably 20°C to 85°C. The treatment time is preferably 1 second to 10 minutes. The water glass treatment may be performed multiple times. However, if the water glass treatment is excessive and the amount of water glass bonded to the surface becomes excessive, the adhesion to the resin will decrease, so water glass treatment under appropriate conditions is required.

After treating the copper material with water glass, it is dried. Drying after treatment can be done by removing moisture with air or by heating. If heating is used, a temperature of 50°C to 250°C is preferred, and the heating time is preferably 10 seconds to 60 minutes.

The coupling agent may be dissolved in water glass used for processing copper materials (hereinafter, this solution will be referred to as the mixture). The concentration of the coupling agent is not particularly limited, but preferably 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9% or more by weight, and preferably 20%, 15%, or 10% or less.

(4) Coupling agent treatment The method for manufacturing the copper member may include a step of treating the oxidized copper material with a coupling agent.

The order of the coupling agent treatment and the water glass treatment is not particularly limited, as long as both treatments are performed at least once each. The coupling agent treatment may be performed only before the water glass treatment, only after, or both before and after. Adding the coupling treatment to the water glass treatment is thought to allow for a more dense coating of the uneven surface, thereby improving acid resistance. Furthermore, performing the coupling treatment after the water glass treatment has a greater effect on enhancing acid resistance in the bonding with the resin. Performing the coupling agent treatment after the water glass treatment strengthens the bond of the water glass to the copper surface, and also removes alkali metals in the water glass components from the copper surface, increasing the proportion of Si compounds in the Si compound layer, thus further improving acid resistance.

Furthermore, when using a mixed agent, the coupling agent treatment and water glass treatment can be performed simultaneously in a single process (hereinafter referred to as the mixed agent treatment). However, one or more coupling agent treatments may be performed before and/or after the mixed agent treatment. Each treatment may also be performed multiple times consecutively.

The coupling agent for treating copper materials is not particularly limited, but silane coupling agents are preferred, and among them, those with two or three hydrolyzable groups are preferred, and those with methoxy or ethoxy groups as hydrolyzable groups are preferred. Specifically, 3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-ureidopropyltrialkoxysilane, 3-acryloxypropyltrimethoxysilane, and the like can be used.

The specific method of coupling agent treatment is not particularly limited. The coupling agent solution may be applied to the copper component surface using a roller or bar coater, sprayed, or the copper material may be immersed in the coupling agent solution. The solvent used in the coupling agent solution may be water, an organic solvent, or a mixture thereof. The concentration of the coupling agent is not particularly limited, but is preferably 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9% or more by weight, and preferably 20%, 15%, or 10% or less.

The copper material is treated with a silane coupling agent solution and then dried. The temperature and time for drying are not particularly limited as long as the solvent completely evaporates, but drying at 70°C for 1 minute or more is preferred, drying at 100°C for 1 minute or more is more preferred, and drying at 110°C for 1 minute or more is even more preferred.

(1) Manufacturing of Copper Components First, copper foil was used as the copper material to manufacture copper components. The processes used in the manufacturing process are summarized in Tables 1 and 2 (Oxidizing Agent Composition). Each process is described in detail below.

(1-1) Copper material In all of the examples and comparative examples, the copper foil used was DR-WS (thickness: 18 μm) (manufactured by Furukawa Electric Co., Ltd.), with the shiny side (glossy side; the side that is flat when compared to the opposite side) being used.

(1-2) Pretreatment All copper foils of the examples and comparative examples were degreased by immersing them in a 40 g/L sodium hydroxide aqueous solution at a liquid temperature of 50°C for 1 minute to remove dirt from the copper surface. After that, the copper foils were washed with water.

Next, the degreased copper foil was acid-washed by immersing it in a 10% by weight sulfuric acid solution at 25°C for 2 minutes to remove the oxide film from the copper surface. Afterward, the copper foil was rinsed with water.

Furthermore, the acid-washed copper foil was immersed in a 1.2 g/L sodium hydroxide aqueous solution (pH 10.5) at 40°C for 1 minute to prevent acid contamination during the subsequent oxidation treatment.

(1-3) Oxidation Treatment The pre-treated copper foil was oxidized using the oxidizing agents and oxidation conditions described in Tables 1 and 2, respectively, to form fine protrusions on the surface of the copper foil. Then, all copper foils of the examples and comparative examples were washed with water at room temperature for 1 minute.

The copper foil of Example 14 was subjected to oxidation treatment, followed by reduction treatment with the reducing agent DMAB (10 g/L dimethylamine borane (DMAB) - 10 g/L sodium hydroxide solution) and the reduction conditions shown in Table 1. Afterward, it was washed with water at room temperature for 1 minute.

(1-4) Coupling process I
The copper foil of Example 12 was subjected to oxidation treatment as described in (1-3), then immersed in 1 vol% KBE-903 (3-aminopropyltriethoxysilane) (Shin-Etsu Chemical Co., Ltd.), and subjected to coupling treatment under the conditions described in Table 1. After washing with water, it was dried under the conditions described in Table 1.

(1-5) Water glass treatment For the copper foils of Examples 1 to 14 and Comparative Examples 1, 4 to 10, after the oxidation treatment in (1-3) or the coupling treatment in (1-4), the copper foils were immersed in water glass and subjected to water glass treatment under the reaction conditions described in Table 1. A 4 wt% aqueous sodium silicate solution ( _SiO₂ / _Na₂O ratio of 2.06 to 2.31) was used as the water glass. After that, the foils were washed with water and dried under the conditions described in Table 1.

(1-6) Coupling Process II
For the copper foils of Examples 7-9, 13, and Comparative Examples 3, 8, and 9, after water glass treatment, the copper foils were immersed in 1 vol% KBE-903 (3-aminopropyltriethoxysilane) (Shin-Etsu Chemical Co., Ltd.) or 0.01 vol% KBM-802 (3-mercaptopropylmethyldimethoxysilane) (Shin-Etsu Chemical Co., Ltd.), and coupling treatment was performed under the conditions described in Table 1. After that, they were washed with water and dried under the conditions described in Table 1.

(2) Test I of copper components
The copper components prepared in (1) were tested as follows. The results are summarized in Table 6.

(2-1) Measurement of Oxide Film Thickness The thickness of the copper oxide film formed by the oxidation treatment was measured using SERA. A Surface-Scan QC-100 (ECI Corporation) was used as the measuring device.

The measurement involved inducing a reduction reaction using boric acid aqueous solutions (6.18 g/L boric acid, 9.55 g/L sodium tetraborate) with a constant current (90 μA/ ^cm² ), and measuring the reduction time within the following voltage range.
Cu ₂ O = -0.3V to -0.55V
CuO=-0.55V to -0.85V
Cu ₂ S = -0.85V to -1.0V

The obtained reduction time and the above current density were substituted into the following formula and converted to film thickness.
_Cu₂O film thickness (nm) = 0.0124 × current density (μA/ ^cm² ) × reduction time (sec) × 0.1
CuO film thickness (nm) = 0.00639 × current density (μA/ ^cm² ) × reduction time (sec) × 0.1
_Cu₂S film thickness (nm) = 0.0147 × current density (μA/ ^cm² ) × reduction time (sec) × 0.1

Table 6 shows the conversion results for each molecule.

(2-2) Height of the protrusions The height of the protrusions on the surface of the copper member was measured by taking five points at 1.03 μm intervals in a 30,000x cross-sectional image of the treated surface of the copper member using a scanning electron microscope, measuring the length from each point to the highest point of the nearest protrusion in the direction perpendicular to the treated surface, and calculating the average value of the five points.

(2-3) Surface roughness (Rz)
The surface shape of the copper foil was measured on the treated surface of the copper component using a confocal scanning electron microscope OPTELICS H1200 (Lasertec Corporation), and Rz was calculated according to the method specified in JIS B 0601:2001 (international standard ISO 4287-1997). The measurement conditions were as follows: scan width 100 μm, scan type area, light source Blue, cutoff value 1/5. The object lens was set to ×100, contact lens to ×14, digital zoom to ×1, and Z pitch to 10 nm. Data was acquired at three locations, and Rz was the average of the three locations. Table 6 shows the average Rz values obtained.

(2-4) Surface development area ratio (Sdr)
The surface shape of the copper foil was measured on the treated surface of a copper component using a confocal scanning electron microscope OPTELICS H1200 (Lasertec Corporation), and the Sdr was calculated. The measurement conditions were as follows: scan width 100 μm, scan type area, light source Blue, scan filter type high-pass, cutoff wavelength 20 μm in both the X and Y directions. The object lens was set to ×100, contact lens to ×14, digital zoom to ×1, and Z pitch to 10 nm. Data was acquired from three locations, and the Sdr was calculated as the average of the three locations. Table 6 shows the average Sdr values obtained.

(2-5) Surface elemental analysis The treated surface of the copper component was subjected to elemental analysis by XPS.

The Quantera SXM (ULVAC-PHI) was used, and scans were performed under the conditions described in Table 3. Narrow spectra were analyzed for C1s (x15), N1s (x20), O1s (x10), Na1s (x20), Si2p (x15), and Cu2p3 (x7) (numbers in parentheses indicate the number of sweeps). The atomic percentages were calculated when the sum of the atomic percentages of C1s, N1s, O1s, Na1s, Si2p, and Cu2p3 was set to 100%, and when the sum of the atomic percentages of N1s, Na1s, Si2p, and Cu2p3 was set to 100%. Table 6 shows the atomic percentages for each element.

Next, the O1s peak was separated into the compounds shown in Table 4 using MultiPak (ULVAC-PHI). Specifically, the Curve Fit function was used, and after setting each parameter as described in Table 4, peak fitting was performed. Table 6 shows the area percentage of the peak area for each compound. In addition, the ratio of (area percentage of peak area of Cu compounds) / (area percentage of peak area of SiO) was calculated as the ratio of the sum of the area percentages of the peak areas of CuO, _Cu₂O , Cu(OH) _₂ , and _CuCO₃ to the area percentage of the peak area of SiO, and is shown in Table 6.

(2-6) Si content per unit area The amount of Si bonded to the copper member surface by water glass treatment was measured per unit area.

First, the copper component was treated with 12% nitric acid to completely dissolve the surface treatment layer (including the copper oxide layer and the Si compound layer). The mass of Si in the eluate was then measured using an ICP emission spectrometer 5100 SVDV ICP-AES (Agilent Technologies). The mass per unit area was then calculated by dividing this by the area of the copper component on which the Si compound layer was formed. The results are shown in Table 6.

(2-7) TOF-SIMS
The surface composition of the fabricated copper components was detected using a TRIFT V nano-TOF apparatus (manufactured by ULVAC-PHI, Inc.) under the conditions shown in Table 5. Representative results are shown in Figure 1.

Table 6 shows the results regarding the presence or absence of any Si compound peaks (indicated by ○ if present, × if not).

(2-8) Acid Resistance The fabricated copper component was immersed in a beaker containing 10% sulfuric acid, and the time until the surface treatment layer (including the copper oxide layer and Si compound layer) completely dissolved was measured. After immersion in sulfuric acid, the copper component was measured using SERA, and if the total thickness of CuO, _Cu₂O , and _Cu₂S was 5 nm or less, it was determined that it had completely dissolved. The obtained times are shown in Table 6.

(2-9) Adhesion An epoxy resin insulating material was laminated onto the treated surface of a copper component, and the component was heat-pressed using a vacuum high-pressure press at a press pressure of 1 MPa, a temperature of 200°C, and a time of 120 minutes. A circuit board was then fabricated by masking with 10 mm wide tape and etching. Subsequently, the peel strength (kgf/cm) was measured by a 90° peel test (Japanese Industrial Standard (JIS) C5016). The measured values are shown in Table 6.

(2-10) Results

In the copper foils of Examples 1 to 14, Si compounds were detected on the surface by TOF-SIMS, and in the O1s spectrum of the copper material surface by XPS, the area percentage of the SiO peak area was 2 Area % or more, and the ratio of (area percentage of the Cu compound peak area) / (area percentage of the SiO peak area) (labeled "Cu-based/SiO" in the table) was greater than 1.0 and less than 15.0. In such cases, the dissolution time was longer than 60 seconds, and the peel strength was greater than 0.4. As in the comparative example, if no Si compounds were detected on the surface by TOF-SIMS, or if the Cu-based/SiO ratio in the O1s spectrum of the copper material surface by XPS was 1.0 or less, or 15.0 or more, the dissolution time was 60 seconds or less, or the peel strength was 0.4 or less. Alternatively, if the area percentage of the SiO peak area in XPS is less than 2 Area%, or if the Cu-based/SiO ratio in the O1s spectrum of the copper component surface obtained by XPS is 1.0 or less, or 15.0 or more, the dissolution time will be 60 seconds or less, or the peel strength will be 0.4 or less.

Furthermore, in the copper foils of Examples 1 to 14, one of the Si compounds was detected on the surface by TOF-SIMS, the amount of Si detected by ICP-AES ^was 10 μg/dm² or more and 150 μg/ ^dm² or less, and the value of (sum of film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by SERA) / (mass of Si per unit area measured by ICP-AES) (indicated as SERA/ICP in Table 6) was greater than 0.5 and less than 10. Even in such cases, the dissolution time was longer than 60 seconds, and the peel strength was greater than 0.4. As in the comparative example, if no Si compound is detected on the surface by TOF-SIMS, or if the amount of Si detected by ICP-AES is less than 10 μg/ ^dm² or greater than 150 μg/ ^dm² , or if the value of (sum of film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by SERA) / (mass of Si per unit area measured by ICP-AES) is 0.5 or less or 10 or more, the dissolution time will be 60 seconds or less, or the peel strength will be 0.4 or less.

In all of Examples 1 to 14, when the ratio of (percentage of Cu2p3 atoms) / (percentage of Si2p atoms) (indicated as "Cu narrow/Si narrow" in the table) in the narrow spectrum of the copper component obtained by XPS was greater than 1.6 and less than 24.0, the dissolution time was longer than 60 seconds and the peel strength was greater than 0.4 kgf/cm.

Furthermore, in all of Examples 1 to 14, the total value of CuO, _Cu₂O , and _Cu₂S measured by SERA is 35 nm or more.

The copper foils of the examples possessing the above characteristics exhibited excellent acid resistance and adhesive properties. In particular, the copper components of Examples 8 and 9, which underwent water glass treatment and coupling treatment, resulting in thicker oxide film thicknesses, and the copper component of Example 14, which underwent reduction treatment before water glass treatment, exhibited remarkably superior acid resistance and adhesive properties. Comparative Examples 2 and 3, lacking water glass treatment, had poor acid resistance; Comparative Examples 4, 6, and 8, with insufficient water glass treatment, had poor acid resistance; and Comparative Examples 1, 5, 7, 9, and 10, with excessive water glass treatment, had poor adhesive properties.

Thus, by performing appropriate water glass treatment and oxidation treatment that is balanced with the water glass treatment, copper foil with the above-mentioned properties, possessing good acid resistance and adhesion, can be obtained.

Claims (17)

Elemental analysis of the surface using time-of-flight secondary ion mass spectrometry (TOF-SIMS) detected Si compounds.
In the waveform separation of the O1s spectrum of the surface by X-ray photoelectron spectroscopy (XPS), the value of (area percentage of peak area of Cu compound) / (area percentage of peak area of SiO) is greater than 1.0 and less than 15.0.
The Cu compound includes copper oxide,
The developed area ratio (Sdr) on the surface of the copper component is 4% or more.
A copper member wherein, in the waveform separation of the O1s spectrum of the surface of the copper member by X-ray photoelectron spectroscopy (XPS) , the area percentage of the peak area of Cu(OH) _₂ relative to the sum of the peak areas of CuO, _Cu₂O , and Cu (OH) _₂ is 45 Area % or less . Elemental analysis of the surface using time-of-flight secondary ion mass spectrometry (TOF-SIMS) detected Si compounds.
The amount of Si detected by elemental analysis of the surface by inductively coupled plasma emission spectroscopy (ICP-AES) is ¹⁰ μg/dm² or more and less than 150 μg/ ^dm² ,
The value of (the sum of the film thicknesses of _Cu₂O , CuO, and _Cu₂S measured by Sequential Electrochemical Reduction Analysis (SERA)) / (the mass of Si per unit area measured by ICP-AES) is greater than 0.5 and less than 10.
The developed area ratio (Sdr) on the surface of the copper component is 4% or more.
A copper member wherein, in the waveform separation of the O1s spectrum of the surface of the copper member by X-ray photoelectron spectroscopy (XPS) , the area percentage of the peak area of Cu(OH) _₂ relative to the sum of the peak areas of CuO, _Cu₂O , and Cu (OH) _₂ is 45 Area % or less . The copper member according to claim 1 or 2, wherein the Si compound is detected within 1 nm of the surface. In the waveform separation of the O1s spectrum of the surface by X-ray photoelectron spectroscopy (XPS), the area percentage of the peak area of SiO is 2Area% or more.
In the waveform separation of the O1s spectrum of the surface by X-ray photoelectron spectroscopy (XPS), the value of (area percentage of peak area of Cu compound) / (area percentage of peak area of SiO) is greater than 1.0 and less than 15.0.
The Cu compound includes copper oxide,
The developed area ratio (Sdr) on the surface of the copper component is 4% or more.
A copper member wherein, in the waveform separation of the O1s spectrum of the surface of the copper member by X-ray photoelectron spectroscopy (XPS) , the area percentage of the peak area of Cu(OH) _₂ relative to the sum of the peak areas of CuO, _Cu₂O , and Cu (OH) _₂ is 45 Area % or less . In the waveform separation of the O1s spectrum of the surface by X-ray photoelectron spectroscopy (XPS), the area percentage of the peak area of SiO is 2Area% or more.
The amount of Si detected on the surface by elemental analysis of the surface using inductively coupled plasma-atomic emission spectroscopy (ICP-AES) is 10 μg/dm² or ^more and less than 150 μg/ ^dm² ,
The value of (sum of _Cu₂O , CuO, and _Cu₂S film thicknesses measured by SERA) / (mass of Si per unit area measured by ICP-AES) is greater than 0.5 and less than 10.
The developed area ratio (Sdr) on the surface of the copper component is 4% or more.
A copper member wherein, in the waveform separation of the O1s spectrum of the surface of the copper member by X-ray photoelectron spectroscopy (XPS) , the area percentage of the peak area of Cu(OH) _₂ relative to the sum of the peak areas of CuO, _Cu₂O , and Cu (OH) _₂ is 45 Area % or less . The copper member according to any one of claims 1 to 5, wherein the sum of the film thicknesses of _Cu₂O , CuO, and _Cu₂S detected by elemental analysis of the surface by SERA is 20 nm or more. The copper member according to any one of claims 1 to 6, wherein, in the surface, the atomic percentage of N1s atoms relative to the total number of N1s, Na1s, Si2p, and Cu2p3 atoms in the XPS Narrow spectrum is 0.5 at% or more. The copper member according to any one of claims 1 to 7, wherein, in the surface, the atomic percentage of Na1s atoms relative to the total number of N1s, Na1s, Si2p, and Cu2p3 atoms in the XPS Narrow spectrum is 0.1 at% or less. The copper member according to any one of claims 1 to 8, wherein the Rz of the surface is 0.39 μm or greater. A method for manufacturing a copper member according to any one of claims 1 to 9, using a copper material,
A first step of oxidizing the copper material,
A second step involves treating the copper material, which has been oxidized in the first step, with a coupling agent.
A third step involves treating the copper material, which has been oxidized in the first step, with water glass.
Methods that include... The method according to claim 10, wherein the second step is performed before, after, or before/after the third step. A method for manufacturing a copper member according to any one of claims 1 to 9, using a copper material,
A first step of oxidizing the copper material,
A method comprising a fourth step of treating the copper material oxidized in the first step with water glass containing a coupling agent. The method according to claim 12, further comprising a fifth step of treating the copper material oxidized in the first step with a coupling agent. The method according to claim 13, wherein the fourth step is performed before, after, or before/after the fifth step. The method according to any one of claims 10 to 14, wherein the coupling agent is one or more selected from the group consisting of 3-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-ureidopropyltrialkoxysilane, and 3-acryloxypropyltrimethoxysilane. A laminate comprising a copper member according to any one of claims 1 to 9, wherein a resin substrate is laminated on the surface of the copper member. A printed circuit board comprising the laminate described in claim 16.