JP5129111B2 - LAMINATE MANUFACTURING METHOD AND CIRCUIT WIRING BOARD MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to a method for manufacturing a laminate for a circuit wiring board and a method for manufacturing a circuit wiring board widely used in the field of electronic equipment and the like.

  In an electronic circuit of an electronic device, a printed wiring board obtained by processing a laminated board made of an insulating material and a conductive material is used. A printed wiring board is formed by fixing a conductive pattern based on electrical design on the surface (and inside) of an insulating substrate with a conductive material. It is roughly divided into a board and a flexible printed wiring board which is rich in flexibility. The flexible printed wiring board is characterized by having flexibility, and is a necessary component for connection in a movable part that constantly bends. In addition, since the flexible printed wiring board can be stored in a bent state in an electronic device, it is also used as a space-saving wiring material. Insulating resins such as polyimide esters and polyimide resins are often used for the base material of the flexible substrate that is the material of the flexible printed wiring board, but the amount of heat-resistant polyimide resin is overwhelmingly large. On the other hand, copper foil is generally used as the conductive material from the viewpoint of conductivity.

  With recent miniaturization of electronic components and increase in signal transmission speed, fine fine pitch circuits are required on circuit boards such as flexible printed boards. As a method for forming a fine fine pitch circuit, methods such as vapor deposition and sputtering are known. However, the metal film formed by these methods has a large variation in adhesive strength with the polyimide resin substrate. There is a problem that pinholes are easily generated in the wiring.

  In recent years, for example, a technique called a direct metallization method as disclosed in Patent Document 1 has been proposed as a technique that can maintain relatively good adhesion between a polyimide resin substrate and a metal film. A part of the metal film obtained by such a method is embedded in the resin of the polyimide resin base material, and high adhesion can be obtained. By adopting such a method, it has become possible to form a thin conductor layer while ensuring high adhesion even if the conductor layer is directly formed on the polyimide resin substrate. However, the conductor layer formed in this manner has a tendency that the adhesiveness with the polyimide resin base material is remarkably lowered after the heat treatment. In order to improve such a decrease in adhesion after heat treatment, for example, Patent Document 2 proposes a polyimide resin base material containing silicon in a layer having a depth of 3 to 5 nm from the resurface of the polyimide resin base material. Has been. However, in the polyimide resin base material of Patent Document 2, the adhesiveness with the conductor layer after the heat treatment is reduced to about 20% to 50% before the heat treatment, so that practically sufficient adhesiveness is provided. Has not reached. In Patent Document 2, a procedure is adopted in which a polyimide resin is plasma-treated, then treated with a silane coupling agent, and then subjected to an alkali treatment to cleave the imide ring of the polyimide resin. The plasma treatment is a treatment for cutting the bond on the surface of the polyimide resin and generating a chemically active functional group such as a hydroxyl group on the surface of the polyimide resin (see Non-Patent Document 1). The generated functional group is a silane coupling. It is thought that it binds to the alkoxysilane of the agent, but by performing an alkali treatment thereafter, this bond is hydrolyzed by the action of alkali, and the coupling agent is detached from the polyimide resin. Insufficient effect is considered to be the cause of the decrease in adhesion after heat treatment. Moreover, in patent document 2, the kind of silane coupling agent is not specified, and sufficient examination is not made about what kind of structure the silane coupling agent should be used.

  Further, Patent Document 3 proposes a method in which an alkali treatment is not performed on a polyimide resin, a plasma treatment is performed, a treatment with a silane coupling agent is performed, and then an electroless plating catalyst is attached. However, even in the technique of Patent Document 3, the bond between the chemically active functional group formed by the plasma treatment and the alkoxysilane of the silane coupling agent tends to be unstable, and the modified layer by the plasma treatment However, since it is only thinly formed in the vicinity of the surface of the polyimide resin, there is a problem that the treatment of the silane coupling agent tends to be insufficient, and the adhesive effect cannot be sufficiently exhibited.

  Furthermore, in order to improve the adhesion between the resin layer and the conductor layer, Patent Document 4 proposes a method of treating a polyimide resin with a solution containing palladium chloride and an azole silane coupling agent. However, in this method, a nitrogen-containing heterocycle such as azole or imidazole is used as a functional group that captures a metal (palladium) serving as a catalyst for electroless plating. In other words, since the palladium chloride and the azole silane coupling agent are mixed in an aqueous solution before the polyimide resin is treated, the azole structure is consumed by the palladium ions, and further, the azole structure and the silane coupling agent. The silanol group produced by the hydrolysis of is less coupled with polyimide than the amino group. Therefore, in such a treatment, it becomes difficult for the silane coupling agent to participate in the bonding with the polyimide resin, and therefore, the adhesion between the conductor layer formed by the method of Patent Document 4 and the resin layer can be sufficiently satisfied. It was not a thing.

JP 2002-256443 A International Publication WO2005 / 39258 Pamphlet JP 2006-54357 A JP 2002-226972 A “Surface Technology” vol.55, No.12, 2004, pp.960-961 (Surface Technology Association)

  The present invention provides a method for producing a laminate and a method for producing a circuit wiring board, which are less likely to cause a decrease in adhesion between a polyimide resin base material and a conductor layer even after heat treatment and are suitable for processing fine wiring. Objective.

The method for producing a laminate according to the present invention is a method for producing a laminate in which a conductor layer is laminated on a polyimide resin layer, which is used for a circuit wiring board,
a) Treating the surface of the polyimide resin layer on the side where the conductor layer is laminated with an alkaline aqueous solution to cleave the imide ring of the polyimide resin to introduce a carboxyl-modified polyimide layer having a thickness of 1 nm to 700 nm Forming in a range of
b) The polyimide modified layer is impregnated with a polar solvent solution containing a silane coupling agent having an amino group, and the amino group of the silane coupling agent and the carboxyl group are reacted, thereby A carboxyl group bonded to an amino group of the silane coupling agent containing a carboxyl group bonded to an amino group and an unreacted carboxyl group, and the carboxyl group bonded to the amino group of the silane coupling agent and an unreacted carboxyl group Forming a polyimide modified layer present at a ratio of 10% or more based on the total of the groups,
c) a step of bringing a palladium ion-containing solution into contact with the unreacted carboxyl group contained in the polyimide modified layer to produce a palladium salt of a carboxyl group;
d) reducing the palladium salt to deposit metal palladium on the surface portion of the polyimide modified layer;
e) a step of depositing a plated metal by electroless plating using the metal palladium as a catalyst, and
f) a step of closing a carboxyl group in the polyimide-modified layer into an imide ring by heat treatment;
It has. In this case, in the step b), after the polyimide modified layer is impregnated with a polar solvent solution containing a silane coupling agent having an amino group, a heat treatment is performed at a temperature in the range of 120 to 130 ° C. May be included.

In addition to steps a) to f) in the method for manufacturing a laminate, the method for manufacturing a circuit wiring board of the present invention includes:
g) forming a mask pattern on the surface of the polyimide modified layer, and selectively exposing the polyimide modified layer;
May be provided. In this case, step g) is preferably performed before step c), and step g) is more preferably performed after step b).

  According to the method for producing a laminate of the present invention, after treatment with an alkaline aqueous solution to form a polyimide modified layer in a thickness range of 1 nm to 700 nm, an amino group of the silane coupling agent and a carboxyl group of the polyimide modified layer To form a carboxyl group bonded to an amino group of the silane coupling agent and an unreacted carboxyl group. Then, a palladium ion-containing solution is brought into contact with the unreacted carboxyl group to produce a palladium salt of the carboxyl group. Therefore, the palladium salt is reduced in the subsequent step d), and palladium is used as a catalyst in the step e). When a plating metal (for example, nickel) is deposited by electrolytic plating, the silanol structure of the silane coupling agent bonded to the polyimide and the plating metal come into contact with each other inside the polyimide modified layer, and a strong metallosiloxane bond (MO— Si) is formed. That is, since the polyimide and the plating metal form a chemical bond inside the modified layer via the silane coupling agent having an amino group, sufficient adhesion between the polyimide resin layer and the conductor layer even after the heat treatment. Therefore, it is possible to provide a laminate suitable for circuit wiring board applications.

  In addition, according to the method for manufacturing a circuit wiring board of the present invention, a fine fine pitch circuit is simplified by a simple process that simplifies the conventional complicated manufacturing process, such as eliminating the need for an etching process of the seed layer (metal deposition layer). Therefore, large-scale capital investment is not required. In addition, since a circuit wiring board having high adhesion reliability between the circuit wiring and the insulating resin layer (polyimide resin layer) can be manufactured, its industrial value is high.

  Hereinafter, a laminate manufacturing method and a circuit board manufacturing method according to embodiments of the present invention will be described in detail with reference to the drawings as appropriate. First, a polyimide resin layer is demonstrated, and the detail of each process in this invention method is demonstrated in order next.

<Polyimide resin layer>
The polyimide resin layer used in the present invention is not particularly limited, and may be a film (sheet) made of polyimide resin, and is a polyimide laminated on a substrate such as a copper foil, a glass plate, or a resin film. It may be a resin layer. However, at least one surface of the polyimide resin layer exists as a surface layer. The thickness of the polyimide resin layer is 3 to 100 μm, preferably 3 to 50 μm.

  The polyimide resin that forms the polyimide resin layer refers to a heat-resistant resin having an imide group in the structure such as polyamideimide, polybenzimidazole, polyimide ester, polyetherimide, polysiloxaneimide, including so-called polyimide resin. Commercially available polyimide resins or polyimide films can also be suitably used. For example, Kapton EN (trade name) manufactured by Toray DuPont Co., Ltd. Apical NPI (trade name) manufactured by Kaneka Chemical Co., Ltd., Ube Industries, Ltd. For example, Iupilex (trade name) manufactured by the company is listed.

  The polyimide resin can be formed by imidizing (curing) a precursor. The precursor here contains a photosensitive group, for example, an ethylenically unsaturated hydrocarbon group, in its molecular skeleton. Also included. Details of imidization will be described later.

When the insulating resin layer of the circuit wiring board is composed of a polyimide resin layer and the polyimide resin layer is composed of a single layer, a low thermal expansion polyimide resin can be suitably used. Specifically, the coefficient of linear thermal expansion (CTE) is in the range of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K), preferably 1 × 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K ), More preferably in the range of 15 × 10 ^{−6 to} 25 × 10 ⁻⁶ (1 / K). Applying such a polyimide resin as an insulating resin layer is advantageous because warpage as a circuit wiring board can be suppressed. However, a polyimide resin exceeding the linear thermal expansion coefficient can also be used, and in this case, the adhesion with the metal deposition layer can be improved.

  As said polyimide resin, the polyimide resin which has a structural unit represented by General formula (1) is preferable.

However, Ar ₁ represents a tetravalent aromatic group represented by Formula (2) or Formula (3), and Ar ₃ represents a divalent aromatic group represented by Formula (4) or Formula (5). R ₁ is independently a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, X and Y are independently a single bond or a divalent hydrocarbon group having 1 to 15 carbon atoms, O, S , CO, SO, SO ₂ or CONH represents a divalent group, n independently represents an integer of 0 to 4, q represents the molar ratio of constituent units, and 0.1 to 1.0 Value.

  The structural unit may be present in the homopolymer or may be present as a structural unit of the copolymer. In the case of a copolymer having a plurality of structural units, it may exist as a block copolymer or a random copolymer. Among polyimide resins having such a structural unit, a polyimide resin that can be suitably used is a non-thermoplastic polyimide resin.

Since a polyimide resin is generally produced by reacting a diamine and an acid anhydride, a specific example of the polyimide resin can be understood by explaining the diamine and the acid anhydride. In the general formula (1), Ar ₃ can be referred to as a diamine residue, and Ar ₁ can be referred to as an acid anhydride residue. Therefore, a preferred polyimide resin will be described using a diamine and an acid anhydride. However, the polyimide resin is not limited to those obtained from the diamine and acid anhydride described here.

  Examples of acid anhydrides include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 4, A preferred example is 4'-oxydiphthalic anhydride. Moreover, 2,2 ', 3,3'-, 2,3,3', 4'- or 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,3 ', 3,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetracarboxylic dianhydride, 2,3 ', 3,4'-diphenyl ether tetracarboxylic dianhydride Bis (2,3-dicarboxyphenyl) ether dianhydride and the like are also preferred. In addition, 3,3``, 4,4 ''-, 2,3,3 '', 4 ''-or 2,2 '', 3,3 ''-p-terphenyltetra Carboxylic dianhydride, 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-dicarboxyphenyl) methane dianhydride, bis Preferred examples include (2,3- or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride and the like.

  Examples of other acid anhydrides include 1,2,7,8-, 1,2,6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6, 7-anthracenetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6, 7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1, 2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetra Carboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic Acid dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclo Pentane-1,2,3,4-te Tracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5 -Tetracarboxylic dianhydride, 4,4'-bis (2,3-dicarboxyphenoxy) diphenylmethane dianhydride and the like.

  Diamines include 4,4'-diaminodiphenyl ether, 2'-methoxy-4,4'-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) Benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl 4,4′-diaminobenzanilide and the like are preferred. Diamines include 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, and bis [4- (3-aminophenoxy) phenyl. ] Sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl, bis [1- (4-aminophenoxy)] biphenyl, bis [1- (3-aminophenoxy) )] Biphenyl, bis [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone, bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 '-(4-aminophenoxy)] Ben Anilide, bis [4,4 '-(3-aminophenoxy)] benzanilide, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) Preferred examples include phenyl] fluorene and the like.

  Examples of other diamines include 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'- Diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3 '-Diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4``-diamino-p-terphenyl, 3,3 ''- Diamino-p-terphenyl, m-phenylenediamine, p-phenylenediamine, 2,6-diaminopyridine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 '-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane Bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis ( 1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) ) Toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2 , 5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine and the like.

  Each of acid anhydrides and diamines can be used alone or in combination of two or more. Further, other acid anhydrides or diamines not included in the general formula (1) can be used together with the acid anhydrides or diamines. In this case, acid anhydrides not included in the general formula (1) Alternatively, the proportion of diamine used is 90 mol% or less, preferably 50 mol% or less. By controlling the types of acid anhydrides or diamines and the molar ratios when using two or more acid anhydrides or diamines, the thermal expansion, adhesion, glass transition point (Tg), etc. are controlled. be able to.

  Synthesis of the precursor can be performed by reacting approximately equimolar acid anhydride and diamine in a solvent. Examples of the solvent to be used include N, N-dimethylacetamide (DMAc), n-methylpyrrolidinone, 2-butanone, diglyme, xylene and the like, and these may be used alone or in combination of two or more. it can.

A thermoplastic polyimide resin can also be used as the polyimide resin. As a precursor used for a thermoplastic polyimide resin, a precursor having a structural unit represented by the general formula (6) is preferable. In General Formula (6), Ar ₄ represents a divalent aromatic group represented by Formula (7), Formula (8), or Formula (9), and Ar ₅ represents Formula (10) or Formula (11). Represents a tetravalent aromatic group, R ₂ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, V and W each independently represents a single bond, and has 1 to 15 carbon atoms. A divalent hydrocarbon group, a divalent group selected from O, S, CO, SO ₂ or CONH, m independently represents an integer of 0 to 4, p represents a molar ratio of constituent units, A value of 0.1 to 1.0.

In the general formula (6), Ar ₄ can be referred to as a diamine residue, and Ar ₅ can be referred to as an acid anhydride residue. Therefore, a preferred thermoplastic polyimide resin will be described using a diamine and an acid anhydride. . However, the thermoplastic polyimide resin is not limited to those obtained from the diamine and acid anhydride described herein.

  Examples of diamines suitably used for forming a thermoplastic polyimide resin include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy). ) Benzene, 1,3-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3 3,3′-dihydroxy-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide and the like. In addition, the diamine mentioned by description of the said polyimide resin can be mentioned.

  Examples of the acid anhydride suitably used for forming the thermoplastic polyimide resin include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4, Examples thereof include 4′-diphenylsulfone tetracarboxylic dianhydride and 4,4′-oxydiphthalic anhydride. In addition, the acid anhydride mentioned by description of the said polyimide resin can be mentioned.

  As for the diamine and the acid anhydride that are preferably used for forming the thermoplastic polyimide resin, only one of them may be used, or two or more of them may be used in combination. In addition, diamines and acid anhydrides other than those described above can be used in combination.

  In the precursor of the thermoplastic polyimide resin, the structural unit represented by the formula (6) may be present in the homopolymer or as a structural unit of the copolymer. In the case of a copolymer having a plurality of structural units, it may exist as a block copolymer or a random copolymer. There are a plurality of structural units represented by formula (6), but they may be one type or two or more types. Advantageously, the main component is the structural unit represented by the formula (6), and the precursor preferably contains 60 mol% or more, more preferably 80 mol% or more.

  A precursor of a synthesized polyimide resin (including a thermoplastic polyimide resin) is used as a solution. Usually, it is advantageous to use as a reaction solvent solution, but if necessary, it can be concentrated, diluted or replaced with another organic solvent. In addition, since the polyimide precursor resin is generally excellent in solvent solubility, it is advantageously used.

  The method for forming the precursor layer is not particularly limited. For example, the precursor layer may be formed by applying a solution of the precursor on an arbitrary underlayer (for example, a substrate) and then drying. The method of applying is not particularly limited, and it is possible to apply with a coater such as a comma, die, knife, lip or the like.

  The polyimide resin layer may be formed of only a single layer or may be formed of a plurality of layers. In the case where a plurality of polyimide resin layers are used, other precursors can be sequentially formed on the precursor layers made of different components. When the precursor layer is composed of three or more layers, the precursor having the same configuration may be used twice or more. Two layers or a single layer having a simple layer structure, particularly a single layer, is preferable because it can be advantageously obtained industrially. The thickness of the precursor layer (after drying) may be in the range of 3 to 100 μm, preferably in the range of 3 to 50 μm.

  As the polyimide precursor resin solution, commercially available products can also be suitably used. For example, U-Varnish-A (trade name), which is a non-thermoplastic polyimide precursor resin varnish manufactured by Ube Industries, Ltd., U-Varnish- S (trade name), thermoplastic polyimide precursor resin varnish SPI-200N (trade name), SPI-300N (trade name), SPI-1000G (trade name) manufactured by Nippon Steel Chemical Co., Ltd., Toray Industries, Inc. Examples include Trenys # 3000 (trade name) manufactured by the manufacturer.

  Moreover, the method of drying and imidation is not particularly limited, and for example, heat treatment such as heating for 1 to 60 minutes at a temperature of 80 to 400 ° C. is suitably employed. By performing such heat treatment, dehydration and ring closure of the polyamic acid proceeds, so that a polyimide resin layer can be formed on the substrate. The polyimide resin layer in which the polyimide resin layer is formed on the substrate may be used as it is, or may be used after being peeled off.

As shown in FIG. 1, the manufacturing method of the laminated body of this Embodiment is equipped with the process a)-the process f), and can include other arbitrary processes as needed.
Step a):
In this step, a polyimide-modified layer having a carboxyl group introduced is formed in a thickness range of 1 nm to 700 nm by treating the surface side of the polyimide resin layer with an alkaline aqueous solution and cleaving the imide ring of the polyimide resin. To do. Note that the carboxyl group herein is meant a carboxylic acid (-COOH), carboxylate of carboxylic acid is to release protons (-COO ^-) is also included.

  As the alkaline aqueous solution, it is preferable to use an alkaline aqueous solution of sodium hydroxide or potassium hydroxide having a concentration of 0.01 to 10 mol / L and a liquid temperature of 5 to 80 ° C. The alkaline aqueous solution can be applied to the polyimide resin layer by, for example, a dipping method, a spray method, or a brush coating method. For example, when applying the dipping method, it is effective to treat the polyimide resin layer with an alkaline aqueous solution for about 5 seconds to 10 minutes, preferably an alkali having a concentration of 0.1 to 5 mol / L and a liquid temperature of 25 to 60 ° C. The polyimide resin layer is preferably treated with an aqueous solution for 20 seconds to 5 minutes. Depending on the structure of the polyimide resin layer, the processing conditions can be appropriately changed. In general, when the concentration of the alkaline aqueous solution is low, the surface treatment time of the polyimide resin layer becomes long. Further, when the temperature of the alkaline aqueous solution increases, the processing time is shortened.

  When treated with an aqueous alkaline solution, the aqueous alkaline solution penetrates from the surface side of the polyimide resin layer, the imide ring of the polyimide resin is cleaved, and a polyimide modified layer is formed by introducing carboxyl groups into the surface side of the polyimide resin layer. . This reaction is thought to be mainly imide bond hydrolysis. The thickness of the polyimide modified layer formed by the modification treatment is in the range of 1 to 700 nm, preferably in the range of 5 to 500 nm, more preferably in the range of 5 to 100 nm. From another point of view, the thickness of the polyimide modified layer is in the range of 1/25000 to 1/36, preferably 1/5000 to 1/50 of the total thickness of the polyimide resin layer. The properties of the polyimide-modified layer after imidation tend to decrease mechanical properties such as tensile strength and toughness as compared to a polyimide resin layer that has not been modified. Therefore, it is preferable that the thickness of the polyimide modified layer does not exceed the upper limit of the above range. If the thickness of the polyimide modified layer exceeds the above upper limit, the ratio of the thickness of the polyimide modified layer to the total thickness of the polyimide resin layer (the total thickness of the unmodified polyimide resin layer and the polyimide modified layer) is Therefore, the fragile mechanical properties derived from the polyimide-modified layer tend to be manifested as the overall properties of the insulating resin layer, and the polyimide-modified layer itself as the adhesion between the insulating resin layer and the conductor layer increases. It is not preferable because cracks tend to be generated. Moreover, when the thickness of the polyimide modified layer is less than the lower limit, the amount of palladium ions adsorbed on the polyimide modified layer described later decreases, and the catalytic function of palladium in subsequent electroless plating is hardly exhibited. In addition, after processing with aqueous alkali solution, it is good to use for process b) by washing with water and drying.

  In the polyimide treatment layer formed by the alkali treatment, there may be a case where a salt of an alkali metal and a carboxyl group at the end of the polyimide resin due to an aqueous alkali solution is formed. Since this carboxyl group alkali metal salt can be replaced with the respective salt by treatment with a silane coupling agent or treatment with palladium ions, which will be described later, the carboxyl group alkali metal salt is added before the next step. There is no problem even if it exists. Moreover, you may neutralize the surface layer of the polyimide resin changed into alkalinity with acid aqueous solution. As an acid aqueous solution, any aqueous solution can be used as long as it is acidic, but a hydrochloric acid aqueous solution and a sulfuric acid aqueous solution are particularly preferable. The concentration of the acid aqueous solution is, for example, preferably in the range of 0.5 to 50% by weight, but preferably in the range of 0.5 to 5% by weight. The pH of the aqueous acid solution is more preferably 2 or less. After washing with an acid aqueous solution, it is preferred to wash with water and then dry and use in the next step.

Step b):
In this step, the polyimide modified layer is impregnated with a solution of a polar solvent containing a silane coupling agent having an amino group and then reacted with an amino group and a carboxyl group of the silane coupling agent. Form. This polyimide modified layer contains a carboxyl group bonded to the amino group of the silane coupling agent and an unreacted carboxyl group, and the carboxyl group bonded to the amino group of the silane coupling agent is an amino group of the silane coupling agent. It exists in the ratio of 10% or more with respect to the sum total of the carboxyl group couple | bonded with group and the unreacted carboxyl group.

  A silane coupling agent having an amino group has an amino group fixed to the carboxyl group of the polyimide modified layer by a chemical bond, and silicon is fixed to the structure by a chemical bond. There is an effect of improving the adhesive strength. In order to effectively express this effect, the ratio of the carboxyl group bonded to the amino group of the silane coupling agent, which is present in the polyimide modified layer, is changed from the carboxyl group bonded to the amino group of the silane coupling agent to the unmodified group. The total amount of carboxyl groups in the reaction is at least 10% or more, preferably 30% or more, more preferably 70% or more. Moreover, the upper limit of the ratio of the carboxyl group couple | bonded with the amino group of a silane coupling agent should just be less than 100%, Preferably it is 95% or less, More preferably, it is 90% or less. When the ratio of the carboxyl group bonded to the amino group of the silane coupling agent exceeds 90%, that is, the unreacted carboxyl group (hereinafter also referred to as a free carboxyl group) that does not participate in the chemical bond with the silane coupling agent. If the proportion is less than 10%, the proportion occupied by the palladium salt of the carboxyl group generated in the polyimide modified layer is low, so the amount of deposited metal palladium necessary to exert the catalytic function in electroless plating is secured. It tends to be difficult. In such a case, it is preferable to increase the amount of deposited metal palladium by repeating step c) and step d) a plurality of times, but as the number of repetitions of step c) and step d) increases, It tends to cause unevenness in the deposition of metallic palladium. Thus, from the viewpoint of achieving both the adhesion effect of the coupling agent and the adsorption effect of palladium ions, the ratio of the carboxyl group bonded to the amino group of the silane coupling agent to be present in the polyimide modified layer is determined as the silane cup. Preferably it is in the range of 10 to 90%, more preferably in the range of 30 to 90%, still more preferably 70 to 90%, based on the total of the carboxyl group bonded to the amino group of the ring agent and the unreacted carboxyl group. It is preferable to be within the range of.

  Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (amino At least one selected from ethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine and N-phenyl-3-aminopropyltrimethoxysilane There should be. In particular, 3-aminopropyltriethoxysilane or 3-aminopropyltrimethoxysilane is preferable.

  The silane coupling agent is used as a polar solvent solution. By using a polar solvent, the polyimide modified layer is uniformly impregnated with the silane coupling agent. As the polar solvent, water or a polar organic solvent containing water is suitable. The polar organic solvent is not particularly limited as long as it is a polar liquid having an affinity for water. Examples of such a polar organic solvent include methanol, ethanol, propanol, isopropanol, acetone, tetrahydrofuran, dimethylformamide, dimethylacetamide and the like. The concentration of the silane coupling agent in the silane coupling agent solution is preferably 0.1 to 5% by weight, and more preferably 0.5 to 1% by weight. If the concentration of the silane coupling agent is high, the amount of the silane coupling agent not only impregnates the polyimide modified layer but also adheres to the surface of the polyimide modified layer, so that a high concentration is not desirable.

  The impregnation method is not particularly limited as long as it is a method capable of bringing a solution of a polar solvent containing a silane coupling agent into contact with the polyimide modified layer surface, and a known method can be used. For example, a dipping method, a spray method, a brush coating method or a printing method can be used. The temperature may be 0 to 100 ° C., preferably 10 to 40 ° C. Moreover, as for the impregnation time, when applying the dipping method, it is effective to treat for 30 seconds to 1 hour, preferably 1 to 15 minutes. By this treatment, a salt of an amino group and a carboxyl group of the silane coupling agent can be present in the polyimide modified layer.

  In order to leave free carboxyl groups in a fixed ratio in the polyimide-modified layer, it is preferable to impregnate a polar solvent containing a silane coupling agent and then wash the polyimide-modified layer after impregnation with a polar solvent. In addition, the method of leaving a free carboxyl group is also possible by controlling the processing conditions in the above-mentioned impregnation method. In the case of washing with a polar solvent, water or a polar organic solvent is suitable as the polar solvent that can be used. The polar organic solvent is not particularly limited as long as it is a polar liquid having an affinity for water. Examples of such a polar organic solvent include methanol, ethanol, propanol, isopropanol, acetone, tetrahydrofuran, dimethylformamide, dimethylacetamide and the like. In this step, excess silane coupling agent adhering to the polyimide modified layer surface can also be removed.

The ratio of the unreacted carboxyl group contained in the polyimide modified layer can be determined by the following operation. First, a target sample A after passing through step b) is prepared, hydrochloric acid in which the polyimide-modified layer of the sample is adjusted to a concentration of 0.1 to 5% by weight, preferably 0.5 to 1% by weight, After washing with an acidic aqueous solution such as sulfuric acid or acetic acid for 5 to 30 minutes, the IR spectrum of the polyimide modified layer is measured for the intensity of each absorption by the ATR (total reflection measurement) method. Among the obtained absorptions, the intensity (S1) of the absorption of the carbonyl group derived from the carboxyl group (approximately 1710 cm ⁻¹ ) and the absorption that does not change even with steps a) and b) (for example, derived from the benzene ring) After reading the intensity (S2) and wave number (W1) of about 1500 cm ⁻¹ , etc., S1 is divided by S2 to obtain the value X (S1 / S2).

Next, sample B after passing through step a) is prepared, the polyimide-modified layer of the sample is washed with an acidic aqueous solution in the same manner as described above, and the IR spectrum of the layer is measured by the ATR method. To do. Among the obtained absorptions, the intensity (P1) of the absorption (about 1710 cm ⁻¹ ) of the carbonyl group derived from the carboxyl group and the intensity of the absorption appearing at the same wave number position as the wave number W1 observed in the sample A ( After reading P2), P1 is divided by P2 to obtain the value Y (P1 / P2). By dividing X thus obtained by Y, the proportion of unreacted carboxyl groups can be determined. In the present invention, the ratio of the carboxyl group bonded to the amino group of the silane coupling agent and the unreacted carboxyl group is expressed as a percentage (%).

  In addition, in the IR spectrum by the ATR method, even when germanium is used as the prism, depending on the wave number, the infrared rays may penetrate from the sample surface to a depth of about 0.3 to 0.5 μm, so the polyimide after passing through step b) When the modified layer is directly measured, if the layer is thinner than 0.5 μm, not only the polyimide modified layer but also the infrared absorption of the unmodified polyimide resin is simultaneously measured. It becomes difficult to correctly grasp the ratio. In this case, after cutting only the polyimide-modified layer with SAICAS (Surface And Interfacial Cutting Analysis System; for example, manufactured by Daipura Wintes Co., Ltd.) or ultramicrotome (for example, manufactured by Hitachi High-Technologies Corporation), the layer is removed. When measured, the proportion of unreacted carboxyl groups can be correctly grasped.

  The polyimide modified layer surface is impregnated with a polar solvent solution containing a silane coupling agent and then dried. The drying method is not particularly limited, and for example, natural drying, spray drying with an air gun, drying with an oven, or the like can be used. The drying conditions depend on the type of polar solvent, but are, for example, 10 to 150 ° C. for 5 seconds to 60 minutes, preferably 25 to 150 ° C. for 10 seconds to 30 minutes, and more preferably 30 to 120 ° C. for 1 minute to 10 minutes. For minutes.

  After drying, heat treatment is performed to condense the carboxyl group of the polyimide modified layer and the amino group of the silane coupling agent. As the heat treatment method, for example, heat treatment using an oven or the like can be used. The heat treatment conditions are preferably 110 ° C. or higher, more preferably 110 ° C. to 150 ° C. for 1 minute to 50 minutes, further preferably 120 ° C. to 130 ° C. for 5 minutes to condense the carboxyl group and the amino group. 10 minutes is good. When treated at a temperature exceeding 150 ° C., the silanol groups of the silane coupling agent condense together to form a siloxane structure, and the bond with the plated metal by electroless plating described later tends to be insufficient, and the adhesive force tends to decrease. This is not preferable. In addition, this heating process can be performed simultaneously with the said drying process by adjusting heating temperature and time.

Step c):
In this step, a palladium ion-containing solution is brought into contact with an unreacted carboxyl group contained in the polyimide modified layer to generate a carboxyl salt palladium salt.

  The palladium ion-containing solution can be prepared by dissolving a palladium salt or an organic complex in a polar solvent. As the polar solvent, for example, water, methanol, ethanol, propanol, isopropanol, acetone, tetrahydrofuran, dimethylformamide, dimethylacetamide and the like can be suitably used. Examples of the palladium salt include palladium chloride, palladium bromide, palladium iodide and the like. Examples of the palladium organic complex include palladium acetylacetone complex, palladium cyanide, palladium-porphyrin complex, and the like. The palladium ion-containing solution preferably contains the palladium salt or palladium organic complex within a range of 1 to 300 mM, and more preferably within a range of 5 to 100 mM. If the concentration of the palladium compound is less than 1 mM, it is not preferable because it takes too much time to adsorb the palladium ions to the free carboxyl group in the polyimide-modified layer, and if it exceeds 300 mM, it is not preferable because it becomes too expensive.

  The palladium ion-containing solution can contain, in addition to the palladium salt or the palladium organic compound complex, components for the purpose of pH adjustment such as ammonia and a buffer solution.

  The palladium salt of a carboxyl group can be produced by impregnating a polyimide-modified layer with a palladium ion-containing solution. The impregnation method is not particularly limited as long as it is a method capable of bringing a palladium ion-containing solution into contact with the polyimide modified layer surface, and a known method can be used. For example, a dipping method, a spray method, a brush coating method or a printing method can be used. The temperature may be 0 to 100 ° C., preferably about 20 to 40 ° C. The impregnation time is preferably 1 minute to 5 hours, for example, and more preferably 5 minutes to 2 hours, when applying the dipping method. When the immersion time is shorter than 1 minute, the adsorption of palladium ions to free carboxyl groups in the polyimide modified layer becomes insufficient, and subsequent electroless plating becomes difficult. On the other hand, there is no problem if the immersion time exceeds 5 hours, but the degree of adsorption of palladium ions on free carboxyl groups tends to be almost flat.

  After impregnating the palladium ion-containing solution, the polyimide modified layer is dried. The drying method is not particularly limited, and natural drying, spray drying with an air gun, oven drying, or the like can be used. Drying conditions are 10 to 150 ° C. for 5 seconds to 60 minutes, preferably 25 to 150 ° C. for 10 seconds to 30 minutes, and more preferably 30 to 120 ° C. for 1 minute to 10 minutes.

Step d):
In this step, the palladium salt is reduced to deposit metal palladium on the surface layer portion of the polyimide modified layer.

  As a reduction method, for example, a wet reduction method or a hydrogen reduction method can be used. In particular, the wet reduction method is a method of reducing metal ions by dipping in a solution containing a reducing agent (reducing agent solution), and it is not necessary to use a large-scale apparatus compared to the hydrogen reduction method. Used for.

  As the reducing agent, for example, boron compounds such as sodium borohydride, potassium borohydride, dimethylamine borane and the like are preferable. Here, when alkali metal such as sodium or potassium is mixed in the polyimide modified layer, there is a concern that a migration phenomenon may occur after the circuit wiring is formed. Therefore, it is preferable to use dimethylamine borane not containing alkali metal. . A boron compound containing an alkali metal such as sodium borohydride can also be used, but it is preferable to add a step of removing the alkali metal. The step of removing the alkali metal will be described later. The boron compound can be used as a solution (reducing agent solution) of water, sodium hypophosphite, formalin, hydrazine, and the like. The concentration of the boron compound in the reducing agent solution is preferably in the range of 0.005 to 0.5 mol / L, for example, and more preferably in the range of 0.01 to 0.1 mol / L. If the concentration of the boron compound in the reducing agent solution is less than 0.005 mol / L, the reduction of palladium ions contained in the polyimide modified layer may be insufficient, and if it exceeds 0.5 mol / L, The polyimide modified layer may be dissolved by the action.

  In the wet reduction treatment, the polyimide-modified layer is placed in a reducing agent solution in the range of 10 to 90 ° C., preferably in the range of 50 to 70 ° C., for example, for 20 seconds to 30 minutes, preferably 30 seconds to 10 seconds. Soak for a period of 1 minute to 5 minutes.

  When palladium ions are reduced by the wet reduction method, palladium ions are reduced from the surface of the polyimide modified layer in contact with the reducing agent solution, and palladium metal is deposited. On the other hand, palladium has a very high reduction rate. Since it is fast, palladium ions are reduced by the permeated reducing agent solution not only in the surface layer portion of the polyimide modified layer but also inside the polyimide modified layer, and metallic palladium is deposited. The metal palladium thus precipitated serves as a catalyst, and it becomes possible to deposit the plating metal in the polyimide modified layer in the subsequent step e). Thereby, the plating metal comes into contact with the silane coupling agent present in the polyimide-modified layer, and the silanol structure of the silane coupling agent and the plating metal form a strong metallosiloxane bond (M—O—Si). . In this manner, a high adhesive strength between the polyimide resin layer and the conductor layer can be exhibited, and the high adhesive strength can be maintained even after heating.

Step e):
In this step, the plating metal is deposited by electroless plating using metal palladium as a catalyst.

  Electroless plating is performed by immersing the polyimide-modified layer on which palladium metal is deposited in an electroless plating solution (electroless plating step). By this electroless plating, an electroless plating layer is formed. The film thickness of the metal film formed by this electroless plating is appropriately set, but is usually 20 nm to 5 μm. Further, it is possible to further form an electroplating film on the electroless plating film by electroplating.

  The electroless plating solution used in the electroless plating process is a neutral to weakly acidic hypophosphite-based nickel plating solution, boron-based nickel plating solution and weakly alkaline in consideration of the influence on the polyimide modified layer. It is preferable to select a nickel-copper alloy-based nickel plating solution. Commercially available products of hypophosphorous acid nickel plating solutions include, for example, Top Nicolon (trade name; manufactured by Okuno Pharmaceutical Co., Ltd.), Nimden KTYVer. 3 (trade name; manufactured by Uemura Kogyo Co., Ltd.). Examples of commercially available boron-based nickel plating solutions include Top Chemialoy B-1 (trade name; manufactured by Okuno Pharmaceutical Co., Ltd.) and Top Chemialoy 66 (trade name; manufactured by Okuno Pharmaceutical Industries, Ltd.). Can do. Furthermore, PFP copper FF (trade name; manufactured by Okuno Pharmaceutical Co., Ltd.) can be mentioned as a commercial product of nickel-copper alloy-based nickel plating solution. The pH of the electroless plating solution is preferably adjusted to 4-9 weak acidity to weak alkalinity. In this case, for example, inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, boric acid and carbonic acid, organic acids such as acetic acid, glycolic acid, citric acid and tartaric acid, inorganic bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide and ammonia PH is adjusted by combining organic bases such as ethylenediamine, triethylamine and pyridine. Further, for example, a weak acid such as boric acid, carbonic acid, acetic acid, and citric acid and an alkali salt thereof may be combined to provide a buffering action. The temperature of the electroless plating treatment can be, for example, in the range of 40 to 95 ° C, and preferably in the range of 45 to 90 ° C. The treatment temperature in the electroless plating step can be 5 seconds to 30 minutes, preferably 10 seconds to 20 minutes, and more preferably 20 seconds to 10 minutes. In consideration of migration resistance after circuit wiring is formed, the electroless plating film is preferably a seed layer for circuit wiring, and the metal deposited by electroless plating is nickel or an alloy containing nickel as a main component. It is preferable that

  FIG. 2 schematically shows chemical changes that occur in the surface layer portion of the polyimide resin substrate between the above steps a) to e). In FIG. 2, reference numeral 1 denotes a polyimide resin substrate, and reference numeral 2 denotes a polyimide modified layer.

Step f):
In this step, the carboxyl group in the polyimide modified layer is closed to the imide ring by heat treatment.

  The imidization method is not particularly limited, and for example, heat treatment such as heating for 1 to 60 minutes under a temperature condition of 80 to 400 ° C. is suitably employed. In order to suppress oxidation of the metal layer formed by reduction or plating, heat treatment in a low oxygen atmosphere is preferable, specifically, in an inert gas atmosphere such as nitrogen or a rare gas, in a reducing gas atmosphere such as hydrogen, Or it is preferable to carry out in a vacuum. In addition, when the step f) is performed before the step e), the dispersion state of the metal palladium formed in the step d) is changed due to the influence of the heat treatment, and the electroless plating in the step e) becomes extremely difficult. The deposited electroless plating film may become non-uniform. Further, if step f) is carried out before step e), condensation of silanol groups of the silane coupling agent itself occurs, making it difficult to form a bond between the plated metal formed by electroless plating and the silanol groups, and adhesion Step f) is preferably performed after step e).

<Electroplating>
Next, it is preferable to perform electroplating using the electroless plating layer as a core to form an electroplating layer (electroplating step). An electroplating layer is formed by electroplating so as to cover the electroless plating layer. For electroplating, a known method can be applied. For example, sulfuric acid, copper sulfate, hydrochloric acid, and brightener [for example, commercially available products such as McCuspec (trade name) manufactured by Nihon McDermitt and Top Lucina SF (trade name) manufactured by Okuno Pharmaceutical Co., Ltd. ) Etc.] in the plating solution having the composition containing the electroless plating layer as a cathode and a metal such as Cu as the anode. Current density in electroplating, for example, is preferably in the range of 0.2~3.5A / dm ^2. As the anode for electroplating, for example, metals such as Ni and Co can be used in addition to Cu. Moreover, chlorides, such as sodium chloride, can also be added to a plating solution as needed.

  As described above, a laminate in which a conductor layer is formed on the surface of the insulating resin layer can be manufactured. This laminated body can be suitably used for applications such as a hard printed board, a flexible printed board, a TAB (Tape Automated Bonding) material, a CSP (Chip Size Package) material, and a COG (Chip on Glass) material. In order to manufacture such a circuit wiring board from the laminate obtained by the present invention, a known procedure may be followed, and there is no particular limitation. As a processing method, for example, the laminate is etched into a predetermined shape. And a method of manufacturing a circuit wiring board.

Step g):
In the case of forming a circuit wiring board, it is preferable to include a step of forming a mask pattern on the surface of the polyimide modified layer and selectively exposing the polyimide modified layer in addition to steps a) to f).

  A known method can be applied to the formation of the resist pattern, and is not particularly limited. For example, it is possible to use a photolithography technique in which a photosensitive resist is laminated or coated on the surface of a polyimide modified layer to form a resist layer, and then exposed, developed, and cured to form a resist pattern.

  Step g) is preferably performed before step c), and can be performed after either step a) or step b) as long as it is before step c). In particular, it is more preferable that step g) is provided after step b). If such a step order is adopted, a palladium salt of a carboxyl group can be selectively generated in a portion not covered with the resist layer. As a result, an electroless plating film can also be selectively formed. When the electroless plating film is used as a seed layer for circuit wiring, a flash etching process for finally removing the seed layer is unnecessary, and the number of processes is reduced. It is possible to reduce and improve the reliability of the circuit wiring board.

  After the circuit wiring is formed, the resist layer that has become unnecessary is peeled off. Although the method of peeling a resist layer is not ask | required, For example, the method of immersing in alkaline solutions, such as 1 to 4 weight% concentration sodium hydroxide aqueous solution and potassium hydroxide aqueous solution, etc. are preferable. Note that if the resist layer is peeled after imidization, the resist layer may be affected by the alkaline solution for removing the resist, and the polyimide resin may be adversely affected. It is preferable to carry out before the conversion. At this time, the concentration of the alkaline solution is preferably 4% by weight or less in order to suppress the alteration of the polyimide modified layer due to the action of the alkaline solution. However, in the case where the resist layer is used as a part of the inter-circuit insulating layer of the circuit wiring, the resist layer is not required to be peeled off.

<Removal of metal ions>
Here, the removal of metal ions in the polyimide modified layer will be described. In the wet reduction process, for example, when alkali metal salts such as sodium borohydride and potassium borohydride are used, or when removing the resist layer, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used. In this case, metal ions derived from the metal salt may be present in the polyimide modified layer, and it is preferable to remove them. The removal of metal ions is preferably performed by immersing in an aqueous solution of acid, and the applicable acid is a polyamic acid because it dissociates metal ions coordinated with the carboxyl groups of the polyimide-modified layer. It is preferable to select a stronger acid (acid dissociation constant pKa of 3.5 or less), and it is more preferable to select an acid that does not dissolve the metal deposited by reduction. Specific examples of such acids include citric acid (pKa = 2.87), oxalic acid (pKa = 1.04), and the like. Note that strong acids such as hydrochloric acid, nitric acid, and sulfuric acid may dissolve the palladium metal or electroless plating metal, and acetic acid (pKa = 4.56) has low acid strength, making it difficult to remove metal ions. This is not preferable. The conditions of the immersion treatment for removing metal ions are as follows. The concentration is within the range of 1 to 15% by weight, preferably within the range of 5 to 10% by weight, and within the range of the temperature of 20 to 50 ° C. It is preferable to immerse within a range of 10 minutes. By performing such an acid treatment, metal ions remaining in the polyimide modified layer can be simultaneously removed after the reduction is completed or after the resist layer is peeled off. The method for removing metal ions is also disclosed in, for example, “17th Microelectronics Symposium Proceedings”, September 2007, pages 179-182.

  EXAMPLES Hereinafter, although an Example demonstrates this invention based on an Example, this invention is not limited at all by these Examples. In the examples of the present invention, unless otherwise specified, various measurements and evaluations are as follows.

[Measurement of adhesive strength]
To measure the adhesive strength, after forming a conductor layer on a polyimide resin, cut it into a strip with a width of 5 mm using a press machine, and peel off the copper foil in a 180 ° direction using STROGRAPH V1 manufactured by Toyo Seiki Co., Ltd. It was measured. The adhesive strength was evaluated as acceptable if the adhesive strength between the polyimide resin layer and the conductor layer after heat treatment at 150 ° C. for 168 hours in air was 0.5 kN / m or more. Moreover, the thing with 80% or more of the adhesive strength retention after the heat treatment before the heat treatment was evaluated as “excellent” and the one with 85% or more was evaluated as “particularly excellent”.

[Measurement of thickness of polyimide treatment layer]
The thickness of the polyimide treatment layer was measured by observing a cross section of the sample using a scanning transmission electron microscope (manufactured by Hitachi High-Technologies Corporation).

[Measurement of unreacted carboxyl group contained in polyimide modified layer and calculation of ratio]
The unreacted carbosyl group contained in the polyimide modified layer is measured by preparing a polyimide modified layer after the treatment with the silane coupling agent, and using a 1% by weight hydrochloric acid aqueous solution (25 ° C.) for 5 minutes. After washing and cutting the polyimide modified layer with an ultramicrotome, the IR spectrum is measured by the ATR method, and the strength (S1) of the absorption (1703 cm ⁻¹ ) of the carbonyl group derived from the carboxyl group is derived from the benzene ring. After reading the absorption intensity (S2) at 1496 cm ⁻¹ , the value X was determined by dividing S1 by S2.

Next, a polyimide-modified layer before the treatment with the silane coupling agent is prepared, washed with a 1% by weight hydrochloric acid aqueous solution (25 ° C.) for 5 minutes, cut with an ultramicrotome, and then the IR spectrum of the layer. Was measured by the ATR method, and after reading the intensity (P1) of absorption (1703 cm ⁻¹ ) of the carbonyl group derived from the carboxyl group and the intensity of absorption (P2) at 1496 cm ⁻¹ , P1 was divided by P2. The value Y was obtained. By dividing the value X by the value Y, the ratio of unreacted carboxyl groups in the polyimide modified layer after the treatment with the silane coupling agent was obtained as a percentage.

  Next, the present invention will be specifically described based on the following examples. Of course, the present invention is not limited to this.

Example 1
A polyimide film (manufactured by Toray DuPont, Kapton EN; thickness 25 μm) is immersed in a 0.5 N aqueous potassium hydroxide solution at 50 ° C. for 45 seconds, and then the immersed polyimide film is sufficiently washed with ion-exchanged water. Thus, a surface-modified polyimide film A1 was produced. The thickness of the polyimide modified layer at this time was 10 nm. It was measured infrared absorption spectrum of the polyimide modified layer in the film A1, absorption of 1580 cm ^-1 and 1406cm ^-1 derived from the potassium salt of a carboxyl group was confirmed. Next, after immersing the film A1 in a 1% by weight aqueous 3-aminopropyltrimethoxysilane (γ-APS) solution (25 ° C.) for 1 minute, the film A1 is immersed in ion-exchanged water for 1 minute, and dried by blowing compressed air. Further, the surface-modified polyimide film B1 was produced by heat treatment at 120 ° C. for 5 minutes. When the infrared absorption spectrum of the polyimide modified layer in film B1 was measured, the absorption of 1050 cm ⁻¹ derived from the siloxane structure was confirmed. The proportion of unreacted carboxyl groups was 16.3% (the proportion of carboxyl groups bonded to the silane coupling agent was 83.7%). The film B1 was immersed in an aqueous solution (25 ° C.) mixed with 10 mM palladium acetate and 60 mM ammonia for 60 minutes, and then dried by spraying compressed air to produce a surface-modified polyimide film C1. The film C1 is immersed in a 50 mM dimethylamine borane aqueous solution (30 ° C.) for 5 minutes, further immersed in an electroless nickel plating (nickel-phosphorus alloy) aqueous solution (90 ° C.) for 20 seconds, and then dried by spraying compressed air. Then, a surface-modified polyimide film 1 subjected to nickel plating was produced. Then, after heat-processing the film 1 for 10 minutes at 300 degreeC under vacuum, the laminated body 1 was produced by performing electrolytic copper plating. The thickness of the copper layer was 15 μm, and the adhesive strength between the polyimide resin layer and the metal layer was 0.8 kN / m.

  Next, the laminated body 1 was heat-treated at 150 ° C. for 168 hours in an air atmosphere. The adhesive strength between the polyimide resin layer and the metal layer after the heat treatment was 0.75 kN / m. The retention rate of the adhesive strength after the heat treatment with respect to that before the heat treatment was 93.8%.

Examples 2-11
After the polyimide film was treated with an aqueous potassium hydroxide solution in the same manner as in Example 1 under the conditions shown in Table 1, laminates 2 to 11 were produced in the same manner as in Example 1. The adhesive strength between the polyimide resin layer and the metal layer in each laminate was measured. The results are summarized in Table 1.

Example 12
Example of Example 1 except that a 0.5 N aqueous potassium hydroxide solution (50 ° C.) was immersed for 10 seconds instead of a 0.5 N aqueous potassium hydroxide solution (50 ° C.) for 45 seconds in Example 1. In the same manner as in Example 1, surface-modified polyimide films A12 and B12 were produced. The thickness of the polyimide-modified layer in film A12 was 2 nm, and the ratio of unreacted carboxyl groups was 16.0% (the ratio of carboxyl groups bonded to the silane coupling agent was 84.0%). The film B12 was treated with palladium acetate and ammonia in the same manner as in Example 1 to produce a surface-modified polyimide film C12, and then treated with dimethylamine borane. After repeating this series of treatments twice on film B12, electroless nickel plating and electrolytic copper plating were performed in the same manner as in Example 1 to produce surface-modified polyimide film 12 and laminate 12. The adhesive strength between the polyimide resin layer and the metal layer was 0.69 kN / m.

  Next, the laminate 12 was heat-treated at 150 ° C. for 168 hours in an air atmosphere. The adhesive strength between the polyimide resin layer and the metal layer after the heat treatment was 0.52 kN / m. The retention rate of the adhesive strength after the heat treatment with respect to that before the heat treatment was 75.4%.

Example 13
Surface-modified polyimide films A13 and B13 were produced in the same manner as in Example 1 except that the immersion in ion exchange water after immersion in the γ-APS aqueous solution in Example 1 was not performed. The ratio of unreacted carboxyl groups in the polyimide-modified layer of film B13 was 8.5% (the ratio of carboxyl groups bonded to the silane coupling agent was 91.5%). The film B13 was treated with palladium acetate and ammonia in the same manner as in Example 1 to produce a surface-modified polyimide film C13, and then treated with dimethylamine borane. After repeating this series of treatments for film B13 three times, electroless nickel plating and electrolytic copper plating were performed in the same manner as in Example 1 to produce surface-modified polyimide film 13 and laminate 13. The adhesive strength between the polyimide resin layer and the metal layer was 0.76 kN / m.

  Next, the laminate 13 was heat-treated at 150 ° C. for 168 hours in an air atmosphere. The adhesive strength between the polyimide resin layer and the metal layer after the heat treatment was 0.70 kN / m. The retention rate of the adhesive strength after the heat treatment before the heat treatment was 92.1%.

Example 14
In the same manner as in Example 1, surface-modified polyimide films A14 and B14 were produced. A dry film resist (manufactured by Asahi Kasei Co., Ltd., trade name: Sunfort AQ, 10 μm thickness) was laminated at a temperature of 110 ° C. on the surface of the polyimide modified layer in the film B14, and exposed to ultraviolet rays through a photomask. Development was performed with a 5% by weight aqueous sodium carbonate solution to form a resist pattern of 50 μm {wiring width / wiring spacing (L / S) = 20 μm / 30 μm} to obtain a film B14 ′ having a resist pattern. Film B14 ′ was treated with palladium acetate and ammonia and treated with dimethylamine borane in the same manner as in Example 1, and then electroless nickel plating was performed to produce film 14 ′. Subsequently, electrolytic copper plating was performed to prepare a copper wiring forming film 14 ′, and after immersion in a 2% by weight sodium hydroxide aqueous solution (25 ° C.) for 3 minutes to remove the resist pattern, 10% by weight Shu Residual metal ions were removed by immersion in an acid aqueous solution (25 ° C.) for 2 minutes.

  The copper wiring formation film 14 ′ was washed with ion exchange water, and then heat-treated at 300 ° C. for 10 minutes under vacuum to obtain a copper wiring formation film 14.

Comparative Example 1
Example 1 and Example 1 except that a 0.5 N aqueous potassium hydroxide solution (50 ° C.) was immersed for 45 seconds instead of a 0.5 N aqueous potassium hydroxide solution (50 ° C.) for 343 seconds. Similarly, after the treatment with the γ-APS aqueous solution, the treatment with palladium acetate and ammonia, and the dimethylamine borane treatment, the electroless nickel plating and the electrolytic copper plating are performed, so that the conductor layer is formed on the polyimide resin layer. A laminated film was obtained. The thickness of the polyimide modified layer in this film was 800 nm, and the adhesive strength between the polyimide resin layer and the metal layer was 0.63 kN / m. The adhesive strength between the polyimide resin layer and the metal layer after heat treatment at 150 ° C. for 168 hours in the air atmosphere is 0.47 kN / m after heat treatment, and the adhesive strength retention is 74.6. %Met.

Comparative Example 2
A film having a conductor layer laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that the treatment with the γ-APS aqueous solution in Example 1 was not performed. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.35 kN / m. Further, the adhesive strength between the polyimide resin layer and the metal layer after the heat treatment at 150 ° C. for 168 hours in the air atmosphere was less than 0.01 kN / m after the heat treatment.

Comparative Example 3
A film having a conductor layer laminated on a polyimide resin layer was obtained in the same manner as in Example 5 except that the treatment with the γ-APS aqueous solution in Example 5 was not performed. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.10 kN / m. Further, the adhesive strength between the polyimide resin layer and the metal layer after the heat treatment at 150 ° C. for 168 hours in the air atmosphere was less than 0.01 kN / m after the heat treatment.

Comparative Example 4
A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 6 except that the treatment with the γ-APS aqueous solution in Example 6 was not performed. The adhesive strength between the polyimide resin layer and the metal layer in this film was less than 0.10 kN / m.

Comparative Example 5
A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 7 except that the treatment with the γ-APS aqueous solution in Example 7 was not performed. The adhesive strength between the polyimide resin layer and the metal layer in this film was less than 0.10 kN / m.

Comparative Example 6
The conductor layer was laminated on the polyimide resin layer in the same manner as in Example 1 except that the treatment with the γ-APS aqueous solution and the washing with ion-exchanged water in Example 1 were performed after the dimethylamine borane treatment. A film was obtained. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.35 kN / m. The adhesive strength between the polyimide resin layer and the metal layer after heat treatment at 150 ° C. for 168 hours in the air was 0.15 kN / m after heat treatment.

Comparative Example 7
A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that the concentration of the γ-APS aqueous solution in Example 1 was 0.001% by weight. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.50 kN / m. The adhesive strength between the polyimide resin layer and the metal layer after the heat treatment at 150 ° C. for 168 hours in the air atmosphere was 0.32 kN / m after the heat treatment. In addition, the ratio of the unreacted carboxyl group in the polyimide modified layer of the surface modified polyimide film after the treatment with the γ-APS aqueous solution was 93.0% (the ratio of the carboxyl group bonded to the silane coupling agent was 7.0). %)Met.

Comparative Example 8
Instead of immersion in 0.5 N aqueous potassium hydroxide and cleaning with ion-exchanged water in Example 1, treatment with oxygen plasma (manufactured by Mori Engineering, VE-1500II) was performed at an oxygen pressure of 17 Pa and a plasma output of 700 W. A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that the conditions were 30 seconds. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.30 kN / m. Further, the adhesive strength between the polyimide resin layer and the metal layer after the heat treatment at 150 ° C. for 168 hours in the air atmosphere was 0.05 kN / m after the heat treatment.

Comparative Example 9
Instead of immersion in 0.5 N aqueous potassium hydroxide and cleaning with ion-exchanged water in Example 1, treatment with oxygen plasma (manufactured by Mori Engineering, VE-1500II) was performed at an oxygen pressure of 17 Pa and a plasma output of 700 W. Before being immersed in an aqueous solution (25 ° C.) mixed with 10 mM palladium acetate and 60 mM ammonia for 60 minutes before being immersed in a 0.5 N aqueous potassium hydroxide solution (50 ° C.). A film having a conductor layer laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that the immersion treatment was performed for 45 seconds. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.35 kN / m. Further, the adhesive strength between the polyimide resin layer and the metal layer after the heat treatment at 150 ° C. for 168 hours in the air atmosphere was 0.08 kN / m after the heat treatment.

Comparative Example 10
Instead of the immersion treatment in the aqueous γ-APS solution in Example 1 and the immersion treatment in the aqueous solution in which palladium acetate and ammonia are mixed, palladium acetate and ammonia are added to the 1 wt% aqueous solution of γ-APS at a concentration of 10 mM and 60 mM, respectively. A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that immersion treatment was performed for 60 minutes in an aqueous solution (25 ° C.) mixed to have a concentration. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.54 kN / m. The adhesive strength between the polyimide resin layer and the metal layer after heat treatment at 150 ° C. for 168 hours in the air atmosphere was 0.38 kN / m after heat treatment.

Comparative Example 11
A film in which a conductor layer was laminated on a polyimide resin layer was obtained in the same manner as in Example 1 except that a γ-APS toluene solution was used instead of the γ-APS aqueous solution in Example 1. The adhesive strength between the polyimide resin layer and the metal layer in this film was 0.59 kN / m. Moreover, the adhesive strength after heat treatment of the polyimide resin layer and the metal layer after heat treatment at 150 ° C. for 168 hours in the air atmosphere was 0.39 kN / m.

  The results of Comparative Examples 1 to 11 are summarized in Table 2.

  From the above results, the laminate formed by the method of the present invention (Examples 1 to 13) has excellent adhesion between the polyimide resin layer and the conductor layer, and is useful as a circuit wiring board (Example 14). It was confirmed that In this method, after the polyimide modified layer is formed in a thickness range of 1 nm to 700 nm, the amino group of the silane coupling agent and the carboxyl group of the polyimide modified layer are reacted to bond with the amino group of the silane coupling agent. By forming a carboxyl group and an unreacted carboxyl group and forming a palladium salt on the unreacted carboxyl group, the silanol group of the silane coupling agent is maximized for adhesion to the electroless plating layer. It was thought that it was because it was available effectively.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. In addition, in the said embodiment, although electroplating was performed after the imidation process, you may perform an electroplating process before an imidation process.

It is drawing which shows the outline of the procedure of the manufacturing method of the laminated body which concerns on one embodiment of this invention. It is drawing explaining the chemical change which arises in the surface layer part of a polyimide substrate between process a) to process e).

Explanation of symbols

  1 ... polyimide resin substrate, 2 ... polyimide modified layer

Claims (6)

A method for producing a laminate in which a conductor layer is laminated on a polyimide resin layer used in a circuit wiring board,
a) Treating the surface of the polyimide resin layer on the side where the conductor layer is laminated with an alkaline aqueous solution to cleave the imide ring of the polyimide resin to introduce a carboxyl-modified polyimide layer having a thickness of 1 nm to 700 nm Forming in a range of
b) The polyimide modified layer is impregnated with a polar solvent solution containing a silane coupling agent having an amino group, and the amino group of the silane coupling agent and the carboxyl group are reacted, thereby A carboxyl group bonded to an amino group of the silane coupling agent containing a carboxyl group bonded to an amino group and an unreacted carboxyl group, and the carboxyl group bonded to the amino group of the silane coupling agent and an unreacted carboxyl group Forming a polyimide modified layer present at a ratio of 10% or more based on the total of the groups,
c) a step of bringing a palladium ion-containing solution into contact with the unreacted carboxyl group contained in the polyimide-modified layer to generate a carboxyl group palladium salt;
d) reducing the palladium salt to deposit metal palladium on the surface portion of the polyimide modified layer;
e) a step of depositing a plated metal by electroless plating using the metal palladium as a catalyst, and
f) a step of closing a carboxyl group in the polyimide-modified layer into an imide ring by heat treatment;
The manufacturing method of the laminated body characterized by comprising.   The step b) includes a heat treatment performed at a temperature in a range of 120 to 130 ° C. after impregnating the polyimide modified layer with a solution of a polar solvent containing a silane coupling agent having an amino group. The manufacturing method of the laminated body of Claim 1 characterized by the above-mentioned. A method for manufacturing a circuit wiring board, comprising:
a) Treating the surface of the polyimide resin layer on the side where the conductor layer is laminated with an alkaline aqueous solution to cleave the imide ring of the polyimide resin to introduce a carboxyl-modified polyimide layer having a thickness of 1 nm to 700 nm Forming in a range of
b) The polyimide modified layer is impregnated with a polar solvent solution containing a silane coupling agent having an amino group, and the amino group of the silane coupling agent and the carboxyl group are reacted, thereby A carboxyl group bonded to an amino group of the silane coupling agent containing a carboxyl group bonded to an amino group and an unreacted carboxyl group, and the carboxyl group bonded to the amino group of the silane coupling agent and an unreacted carboxyl group Forming a polyimide modified layer present at a ratio of 10% or more based on the total of the groups,
c) a step of bringing a palladium ion-containing solution into contact with the unreacted carboxyl group contained in the polyimide-modified layer to generate a carboxyl group palladium salt;
d) reducing the palladium salt to deposit metal palladium on the surface portion of the polyimide modified layer;
e) a step of depositing a plated metal by electroless plating using the metal palladium as a catalyst, and
f) a step of closing a carboxyl group in the polyimide-modified layer into an imide ring by heat treatment;
g) forming a mask pattern on the surface of the polyimide modified layer, and selectively exposing the polyimide modified layer;
A method of manufacturing a circuit wiring board, comprising: 4. The method for manufacturing a circuit wiring board according to claim 3 , wherein step g) is performed before step c). 5. The method of manufacturing a circuit wiring board according to claim 4 , wherein step g) is performed after step b).   The step b) includes a heat treatment performed at a temperature in a range of 120 to 130 ° C. after impregnating the polyimide modified layer with a solution of a polar solvent containing a silane coupling agent having an amino group. The method for manufacturing a circuit wiring board according to any one of claims 3 to 5, wherein

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