JP2010093114A - Method of manufacturing circuit wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a circuit wiring board having high adhesion reliability between a circuit wiring and an insulating resin layer at a fine fine pitch while simplifying a conventional complicated manufacturing process.
A method of manufacturing a circuit wiring board includes a step S1 for forming a polyimide precursor resin layer, a step S2 for impregnating the polyimide precursor resin layer with metal ions, and a resist ink attached to a pattern shape surface. Step S3 for preparing a mold, Step S4 for forming a resist mask by bringing the pattern shape surface of the mold into contact with the surface of the polyimide precursor resin layer, and reducing the metal ions in the polyimide precursor resin layer to form a metal deposition layer. Step S5 for forming the circuit wiring, Step S6 for forming the circuit wiring on the metal deposition layer, and Step S7 for imidizing the polyimide precursor resin layer to form the polyimide resin layer.
[Selection] Figure 1

Description

  The present invention relates to a method of manufacturing a circuit wiring board used for an electronic component, and more particularly to a method of manufacturing a circuit wiring board formed by forming a circuit wiring having a pattern on a polyimide resin layer.

  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. Depending on the type of insulating resin used as a base material, a plate-shaped rigid printed wiring board And flexible printed wiring boards that are flexible. 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, a technique is known in which a seed layer is formed by a technique such as vapor deposition or sputtering, and then wiring is formed by electroless plating and electroplating. However, the metal film formed by these methods has a problem that variation in adhesive strength with the polyimide resin base material is large or that pinholes are easily generated in the wiring. Further, the above method includes a step of removing an unnecessary seed layer remaining on the polyimide resin base material by etching after the wiring is formed. Therefore, there is a concern that overetching due to erosion of the etching liquid on the wiring may occur. .

  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 this method is embedded in the resin of the polyimide resin base material, and high adhesion is obtained. A method has been proposed in which the direct metallization method is applied and the etching process of the seed layer is not required. For example, in Patent Document 2, a pattern-shaped microchannel is formed on the surface of a polyimide resin substrate, an alkaline solution is supplied to the microchannel, and a modified layer is formed on the surface of the polyimide resin substrate. A method of forming a metal film by bringing a metal ion into contact with the modified layer and reducing the metal ion is disclosed. Patent Document 3 discloses a method in which a hydrophobic substance is attached to the surface of a polyimide resin and the exposed portion is selectively subjected to alkali treatment.

  By the way, as one means for forming a fine pattern in units of microns, a microcontact printing technique using a mold on which a fine pattern is formed is known. Regarding this microcontact printing technology, for example, resist ink is applied to a stamp having an uneven surface corresponding to a pattern, the resist ink is transferred onto an ITO / IZO film, and then the region where the resist ink is not attached is etched. Thus, a method for patterning the ITO / IZO electrode has been proposed (Non-Patent Document 1).

JP 2001-73159 A JP 2007-103479 A Japanese Patent Laid-Open No. 2007-242688 Breen et al, Langmuir, 18, No.1 (2002), p194-p197

  As in the invention of Patent Document 2, in the pattern forming method for forming the microchannel, it is necessary to select an alkali-resistant material as a mask material for forming the microchannel groove, and the selection of the material is not easy There is a problem. Further, the method of Patent Document 2 has a problem that high dimensional accuracy is required for processing of the mask material in order to improve pattern accuracy. In particular, if the processing accuracy of the contact portion between the polyimide resin base material and the mask material is low, a gap is formed between the two, and the processing liquid such as a metal ion-containing solution or a reducing solution oozes out there, so that the pattern accuracy is improved. There is a concern that the electrical characteristics of the circuit may be adversely affected.

  In the invention of Patent Document 3, it is necessary to perform plasma treatment in order to adhere a hydrophobic substance that does not dissolve in an alkaline aqueous solution to the polyimide surface, and plasma treatment is also necessary when removing the hydrophobic substance. is there. Further, in the invention of Patent Document 3, it is necessary to form a mask layer by a photolithography technique prior to the attachment of the hydrophobic substance and to peel off the mask layer after the attachment. This means that in order to pattern the hydrophobic substance as a mask, another mask layer (resist pattern) is formed and a step of peeling is necessary, and the number of steps is unnecessarily large. There was a problem of being complicated.

  In the technique described in Non-Patent Document 1 relating to microcontact printing, a photolithography process is unnecessary, but wiring pattern formation is performed by etching a region where resist ink is not attached. May be reduced.

  The present invention has been made in view of the above circumstances, and manufactures a circuit wiring board having high adhesion reliability between a circuit wiring and an insulating resin layer at a fine fine pitch while simplifying a conventional complicated manufacturing process. It aims to provide a method.

The method for manufacturing a circuit wiring board of the present invention is a method for manufacturing a circuit wiring board formed by forming circuit wiring on a polyimide resin layer,
a) a step of preparing a mold with resist ink by attaching resist ink to a pattern shape surface of a mold having a pattern shape;
b) The resist ink is adhered to the surface of the polyimide precursor resin layer including the polyimide resin precursor by bringing the pattern shape surface of the template with the resist ink into contact therewith, and the polyimide precursor resin layer Forming a resist mask patterned on the surface;
c) A step of forming a metal ion-containing polyimide precursor resin layer by impregnating a polyimide precursor resin layer including a polyimide resin precursor with an aqueous solution containing metal ions and drying the polyimide resin resin layer;
d) a step of forming a metal deposition layer by reducing the metal ions in the polyimide precursor resin layer to deposit a metal on a surface layer portion of the polyimide precursor resin in a region not covered with the resist mask;
e) forming a circuit wiring having a pattern on the metal deposition layer by electroless plating and / or electroplating; and
f) imidizing the polyimide precursor resin layer by heat treatment to form the polyimide resin layer;
It is characterized by providing.

  In the method for manufacturing a circuit wiring board of the present invention, step b) may be performed after step c) or before step c).

  In the method for manufacturing a circuit wiring board of the present invention, the polyimide precursor resin layer may be formed by treating the surface side of the polyimide resin layer with an alkaline aqueous solution, or on the substrate. It may be formed by applying a polyimide precursor resin solution and drying.

  In the method for manufacturing a circuit wiring board according to the present invention, a method of adhering a resist ink by bringing a pattern shape surface of a mold with a resist ink into contact with the surface of a polyimide precursor resin layer is employed. Therefore, a resist mask can be easily formed with a small number of steps without requiring a photolithography process and a mask etching process as in the prior art. In addition, the resist mask components are partially impregnated on the surface of the polyimide resin and chemically bonded to the polyimide resin, so that they have heat resistance and are commonly used in photolithography technology. Unlike the resist material, it is not necessary to peel off and the number of steps can be further omitted. Further, in the method of the present invention, since the metal is deposited only on the surface layer portion of the polyimide precursor resin in the region not covered with the resist mask to form the metal deposition layer, the seed layer that is no longer necessary as in the prior art ( It is not necessary to remove the metal deposition layer) by etching.

  As described above, in the method of the present invention, a fine fine pitch circuit can be formed by a simple process that simplifies the conventional complicated manufacturing process, such as eliminating the need for a photolithography process and a seed layer etching process. Does not require large-scale capital investment. 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.

  In addition, the resist mask used in the method of the present invention has a function of fixing the mask portion, that is, the surface of the polyimide resin between the wirings and increasing the surface insulation resistance between the wirings. The effect which suppresses is also acquired.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2 as appropriate. FIG. 1 is a flowchart showing the main process steps of the circuit wiring board manufacturing method according to the present embodiment, and FIG. 2 is an explanatory diagram of each process. A circuit wiring board 100 obtained by the manufacturing method of the present invention is obtained by forming circuit wiring 9 on a polyimide resin layer 3b as shown in FIG. 2 (g), for example. Although the circuit wiring board 100 shown in FIG. 2G includes the underlayer 1, the underlayer 1 is not essential.

[Formation of polyimide precursor resin layer]
In the method for manufacturing a circuit wiring board according to the present invention, first, as shown in FIGS. 1 and 2A, a polyimide precursor resin layer 3 is formed on the base layer 1 (step S1). The polyimide precursor resin layer 3 is formed by, for example, a method (Method A) in which a surface layer of a polyimide resin layer as the underlayer 1 is treated with an alkaline aqueous solution or an arbitrary base material as the underlayer 1. It is obtained by a method (Method B) of forming by applying and drying a solution of a polyimide precursor resin.

  The polyimide precursor resin means a resin in a state where the imide ring of the polyimide resin is opened. The polyimide resin layer 3b is formed by opening a polyimide resin layer (I) formed by imidizing the polyimide precursor resin layer 3 and an imide ring of the polyimide resin of the polyimide resin layer (I). There is a polyimide resin layer (II) formed by imidizing the polyimide precursor resin layer 3 again. When it is necessary to distinguish the types of polyimide resin layers, the former is referred to as “polyimide resin layer (I)” and the latter is referred to as “polyimide resin layer (II)”. Moreover, the polyimide precursor resin that forms the polyimide resin layer (I) may be abbreviated as “precursor”. The polyimide precursor resin via imidization that forms the polyimide resin layer (II) may be abbreviated as “polyamic acid”. Since the precursor or polyamic acid and the polyimide resin are in a relationship between the precursor and the product, the structure of the other is understood by explaining one of them. Common parts will be described simultaneously.

  The aspect of the polyimide resin layer 3b is not specifically limited, A film (sheet | seat) may be sufficient and the thing of the state laminated | stacked on base materials, such as metal foil, a glass plate, and a resin film, may be sufficient. Here, the “base material” refers to a sheet-like resin, a glass substrate, a ceramic, a metal foil or the like on which the polyimide resin layer 3b is laminated. The total thickness of the polyimide resin layer 3b can be in the range of 3 to 100 μm, preferably in the range of 3 to 50 μm.

  The polyimide resin that forms the polyimide resin layer 3b includes so-called polyimides, and imide groups are included in the structure as represented by polyamideimide, polybenzimidazole, polyimide ester, polyetherimide, polysiloxaneimide, and the like. The heat resistant resin which has is mentioned. 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 polyimide resin layer 3b of the circuit wiring board 100 is composed of a single layer, a low thermal expansion polyimide resin can be suitably used. Specifically, the range of linear thermal expansion coefficient (CTE) of ^{1 × 10 -6 ~30 × 10 -6} (1 / K), preferably ^{1 × 10 -6 ~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 of the circuit wiring board 100 can be suppressed. However, a polyimide resin exceeding the linear thermal expansion coefficient can also be used, and in that case, adhesion to the metal deposition layer 7 (described later) can be improved.

As said polyimide resin, the polyimide resin which has a structural unit represented by General formula (1) is preferable. In General Formula (1), Ar ₁ represents a tetravalent aromatic group represented by Formula (2) or Formula (3), and Ar ₂ represents a divalent group represented by Formula (4) or Formula (5). R ₁ independently represents a monovalent hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, and X and Y independently represent a single bond or a divalent hydrocarbon having 1 to 15 carbon atoms. A divalent group selected from a group, O, S, CO, SO, SO ₂ or CONH, n ₁ independently represents an integer of 0 to 4, q represents an abundance ratio of structural units, and 0. A value of 1 to 1.0.

  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 above general formula (1), Ar ₂ 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 the diamine and the acid anhydride 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 diamines or acid anhydrides. In this case, the diamine or acid not included in the general formula (1). The proportion of anhydride used is 90 mol% or less, preferably 50 mol% or less. Controlling thermal expansion, adhesiveness, glass transition point (Tg), etc. by selecting the type of diamine or acid anhydride or the molar ratio of each of two or more diamines or acid anhydrides. be able to.

  The precursor can be synthesized by reacting approximately equimolar amounts of diamine and acid anhydride 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 ₃ 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 ₁ independently represents an integer of 0 to 4, and p represents a molar ratio of constituent units; The value of 0.1 to 1.0.

In the general formula (6), Ar ₃ can be referred to as a residue of diamine, and Ar ₄ can be referred to as a residue of acid anhydride. Therefore, a preferable thermoplastic polyimide resin will be described with diamine and 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 thermoplastic polyimide resins 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 non-thermoplastic polyimide resin can be mentioned. Among these, particularly preferable diamine components include 1,3-bis (4-aminophenoxy) -2,2-dimethylpropane (DANPG), 2,2-bis [4- (4-aminophenoxy) phenyl] propane ( BAPP), 1,3-bis (3-aminophenoxy) benzene (APB), paraphenylenediamine (p-PDA), 3,4'-diaminodiphenyl ether (DAPE34), 4,4'-diaminodiphenyl ether (DAPE44) One or more selected diamines are preferred.

  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 non-thermoplastic polyimide resin can be mentioned. Among these, particularly preferred acid anhydrides include pyromellitic anhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'- Examples thereof include at least one acid anhydride selected from benzophenone tetracarboxylic dianhydride (BTDA) and 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA).

  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 can be formed by applying the precursor solution onto the underlayer 1 and then drying it. 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. Thereafter, it can be dried to form a precursor layer.

The precursor layer can be dried and used as it is. In drying, the temperature is controlled so that imidization due to the progress of dehydration and ring closure of the polyimide precursor resin is not completed. The method for drying is not particularly limited, and for example, drying may be performed under a temperature condition in the range of 60 to 200 ° C. over a time in the range of 1 to 60 minutes, preferably 60 to 150. It is preferable to perform the drying under a temperature condition within a range of ° C. It is necessary to leave the precursor state in order to impregnate the aqueous solution containing metal ions. The precursor layer after drying may have part of the precursor structure imidized, but the imidization rate should be 50% or less, more preferably 20% or less, leaving the precursor structure at 50% or more. Is preferred. In addition, the imidation ratio of the precursor is 1,000 cm by measuring the infrared absorption spectrum of the polyimide thin film by a transmission method using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). ^-1 benzene ring carbon hydrogen bond as a reference is calculated from the absorbance from the imide groups 1,710Cm ^-1.

  The polyimide resin layer (II) can be produced by drying and imidizing the above precursor layer into a polyimide resin layer (I) as an intermediate. The method of drying and imidization is not particularly limited, and for example, a heat treatment in which the precursor layer is heated at a temperature of 80 to 400 ° C. for 1 to 60 minutes is suitably employed. By performing such heat treatment, dehydration and ring closure of the precursor proceeds, so that the polyimide resin layer (I) can be formed on the substrate. Thus, the polyimide resin layer (I) formed on the base material may be used as an intermediate for producing the polyimide resin layer (II) as it is, or peeled off from the underlayer 1 to form a film shape. Alternatively, it may be used in the form of a sheet. The polyimide resin layer (I) as an intermediate formed in this way is treated with an aqueous alkaline solution to form a polyamic acid layer, and the formed polyamic acid layer surface is impregnated with a solution containing metal ions. Can be made. A treatment method with an alkaline aqueous solution will be described later.

  The polyimide resin layer 3b 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. In the method of applying the precursor (Method B), the thickness of the precursor layer can be freely adjusted as compared with the alkali treatment method (Method A). For this reason, by forming the precursor layer to a thickness of 3 μm or more by Method B, a sufficient amount of impregnation of metal ions can be ensured in a metal ion impregnation step (described later). As a result, the metal deposition layer 7 in the metal deposition layer forming step (described later) can be formed into a conductive film.

  When a plurality of precursor layers are used, it is preferable to form the precursor layer so that the polyimide resin layer in contact with the metal deposition layer 7 (described later) becomes a thermoplastic polyimide resin layer. By using a thermoplastic polyimide resin, the adhesion with the metal deposition layer 7 can be improved. Such a thermoplastic polyimide resin preferably has a glass transition temperature (Tg) of 350 ° C. or lower, more preferably 200 to 320 ° C.

  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.

  Next, Method A for forming the alkali-treated layer (polyamic acid layer) by treating the surface with an alkaline aqueous solution when the base layer 1 is a polyimide resin layer will be described. As the alkaline aqueous solution, it is preferable to use an alkaline aqueous solution of sodium hydroxide or potassium hydroxide having a concentration in the range of 0.5 to 50% by weight and a liquid temperature in the range of 5 to 80 ° C. As the alkaline aqueous solution, for example, a dipping method, a spray method, a brush coating, or the like can be applied. For example, when applying the dipping method, it is effective to perform the treatment for 10 seconds to 60 minutes. Preferably, the surface of the polyimide resin layer is treated for 30 seconds to 10 minutes with an alkaline aqueous solution having a concentration of 1 to 30% by weight and a liquid temperature of 25 to 60 ° C. 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 the treatment is performed with an alkaline aqueous solution, the alkaline aqueous solution penetrates from the surface side of the polyimide resin layer, and the polyimide resin layer is modified. It is considered that the modification reaction by the alkali treatment is mainly hydrolysis of imide bonds. The thickness of the alkali treatment layer formed by the alkali treatment is in the range of 1/200 to 1/2 of the thickness of the polyimide resin layer, and preferably in the range of 1/100 to 1/5. From another viewpoint, the thickness of the alkali treatment layer is in the range of 0.005 to 3.0 μm, preferably in the range of 0.05 to 2.0 μm, more preferably in the range of 0.1 to 1.0 μm. Inside is good. By setting the thickness within such a range, it is advantageous for forming the metal deposition layer 7. If the thickness of the alkali-treated layer is less than the above lower limit (0.005 μm), metal ions sufficient for metal deposition cannot be sufficiently impregnated, so that sufficient adhesion strength between the polyimide resin layer and the metal deposition layer 7 is hardly exhibited. . On the other hand, in the treatment with the alkaline aqueous solution of the polyimide resin layer, there is a tendency to cause dissolution of the outermost layer portion of the polyimide resin layer simultaneously with the opening of the imide ring of the polyimide resin, so that the above upper limit (3.0 μm) is exceeded. Have difficulty.

  When the polyimide resin layer is a polyimide film, both surfaces may be simultaneously modified by alkali treatment. Alkali treatment is particularly effective for the polyimide resin layer composed of the above-described low thermal expansion polyimide resin, which is preferable. Since the low thermal expansion polyimide resin has good compatibility (wetability) with an alkaline aqueous solution, the ring-opening reaction of an imide ring by an alkali treatment easily occurs.

  In the alkali-treated layer formed by the alkali treatment, a salt of an alkali metal and a carboxyl group at the end of the polyimide resin or the like due to the aqueous alkali solution may be formed. This alkali metal salt of the carboxyl group can be replaced with a metal ion salt by a metal ion impregnation process in the metal ion impregnation step described later, so that the metal ion salt exists before being subjected to the metal ion impregnation step. There is no problem even if you do. 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 the acid aqueous solution, it is preferable to wash with water and then dry and use it for the next metal ion impregnation step.

[Metal ion impregnation]
Next, as shown in FIG. 1 and FIG. 2B, the polyimide precursor resin layer 3 is impregnated with an aqueous solution containing metal ions (hereinafter sometimes referred to as “metal ion solution”). Then, it is dried to form a polyimide precursor resin layer containing metal ions (hereinafter also referred to as “metal ion-containing layer 3a”) (step S2). Here, the polyimide precursor resin layer 3 is formed by applying a polyimide precursor solution or by alkali treatment of a polyimide resin as described above. By this impregnation treatment, the carboxyl group present in the polyimide precursor resin layer 3 becomes a metal salt of the carboxyl group.

  As the metal ions, ions of metal species having a redox potential higher than the redox potential of the reducing agent used in the reduction step can be used without particular limitation. Examples of the metal compound containing such metal species include those containing metal species such as Cu, Ni, Pd, Ag, Au, Pt, Sn, Fe, Co, Cr, Rh, and Ru. As the metal compound, a salt of the metal, an organic carbonyl complex, or the like can be used. Examples of the metal salt include hydrochloride, sulfate, acetate, oxalate, and citrate. Metal salts are preferably used when the metal is Cu, Ni or Pd. Examples of the organic carbonyl compound capable of forming an organic carbonyl complex with the metal include β-diketones such as acetylacetone, benzoylacetone, and dibenzoylmethane, and β-ketocarboxylic acid esters such as ethyl acetoacetate. .

Preferred specific examples of the metal _{compounds, Ni (CH 3 COO) 2} , Cu (CH 3 COO) 2, Pd (CH 3 COO) 2, NiSO 4, CuSO 4, PdSO 4, NiCO 3, CuCO 3, PdCO 3, NiCl ₂ , CuCl ₂ , PdCl ₂ , NiBr ₂ , CuBr ₂ , PdBr ₂ , Ni (NO ₃ ) ₂ , NiC ₂ O ₄ , Ni (H ₂ PO ₂ ) ₂ , Cu (NH ₄ ) ₂ Cl ₄ , CuI, List Cu (NO ₃ ) ₂ , Pd (NO ₃ ) ₂ , Ni (CH ₃ COCH ₂ COCH ₃ ) ₂ , Cu (CH ₃ COCH ₂ COCH ₃ ) ₂ , Pd (CH ₃ COCH ₂ COCH ₃ ) ₂ Can do.

  In the metal ion solution used in the impregnation step, the metal compound is preferably contained within a range of 30 to 300 mM, and more preferably within a range of 50 to 100 mM. If the concentration of the metal compound is less than 30 mM, it is not preferred because it takes too much time to impregnate the metal ions in the polyimide precursor resin layer 3 (or in the polyamic acid layer), and if it exceeds 300 mM, the polyimide precursor resin layer 3 ( There is a concern that the surface of the polyamic acid layer) may corrode (dissolve).

  In addition to the metal compound, the metal ion solution can contain components intended for pH adjustment such as a buffer solution.

  The impregnation method is not particularly limited as long as the metal ion solution can be brought into contact with the surface of the polyimide precursor resin layer 3 (or the polyamic acid layer), 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 impregnation temperature may be 0 to 100 ° C., preferably 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 5 minutes, the polyimide precursor resin layer 3 (or polyamic acid layer) is not sufficiently impregnated with metal ions, and the anchor effect described later cannot be sufficiently obtained. On the other hand, even when the immersion time exceeds 5 hours, the degree of impregnation of the metal ion polyimide precursor resin layer 3 (or polyamic acid layer) tends to be almost flat.

  Dry after impregnation. 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. 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.

[Preparation of resist ink adhesion mold]
Next, as shown in FIG. 1 and FIG. 2C, a mold 10 is prepared in which the resist ink 5a adheres to the concavo-convex pattern shape surface 10a (step S3). The mold 10 having the concavo-convex pattern shape surface 10a is used when the resist ink 5a attached to the convex portions of the pattern is transferred to the metal ion-containing layer 3a. For this purpose, the mold 10 is preferably a material having good resist ink 5a wettability and chemical resistance to the resist ink 5a. For example, PDMS (polydimethylsiloxane), fluororesin, quartz, Materials made of silicon oxide, silicon carbide, glass, silicon, nickel, tantalum and the like can be preferably used. The mold 10 may be composed of a single material, or may be supported by a hard base material. The uneven pattern of the mold 10 can be formed by a known photolithography technique and etching. Further, the pattern shape surface 10a of the mold 10 may be subjected to plasma treatment or treatment with a surface modifier in order to improve wettability with the resist ink 5a.

  The mold 10 has an uneven pattern corresponding to the negative type of the patterned conductor layer (circuit wiring 9) of the circuit wiring board 100. The width of the concave portion (or the width of the convex portion) in the pattern shape surface 10a of the mold 10 is preferably 0.05 μm or more, and the depth (or the height of the convex portion) of this concave portion is 0.5 μm or more. It is preferable. By setting it as such a range, it can suppress that a pattern is crushed at the time of adhesion of the resist ink 5a to the casting_mold | template 10, and the transfer to a resin layer. Depending on the application of the circuit wiring board 100, the width of each of the irregularities of the pattern-shaped surface 10a in the mold 10 can be arbitrarily changed within the above range. For example, in the flexible wiring board application, the width of the recess (or The width of the convex portion is preferably in the range of 1 to 25 μm. Furthermore, the shape of the mold 10 may be a flat plate shape for performing batch printing, or a roll shape for making it continuous.

  The resist ink 5a contains an ink solute that forms a hydrophobic resist layer and a solvent for diluting it. In order to adjust the adhesion amount or transfer amount of the resist ink 5a, it is desirable to dilute with a solvent and adjust the concentration. It is preferable that the resist ink 5a has good wettability with respect to the concavo-convex pattern of the mold 10 used for printing, and the resist ink 5a can be uniformly attached. After volatilization of the solvent, it is liquid or semi-solid, and it is desirable to have fluidity and adhesiveness at the time of ink transfer to the polyimide precursor resin surface. After the transfer of the resist ink 5a, it is desirable to fix it on the polyimide precursor resin surface by drying or heating to develop hydrophobicity.

  Ink solutes fix on the polyimide precursor resin surface and develop hydrophobicity, so organic functional groups (for example, amino groups, epoxy groups, etc.) for chemically bonding with polyimide resins, hydrophobic groups and chemical structures exhibiting water repellency It is desirable to have Specific examples of the ink solute include a terminal-modified silicone, a silane coupling agent, and an epoxy oligomer. This will be described in order below.

<Terminal modified silicone>
The terminal-modified silicone is amino-modified or epoxy-modified silicone, and as shown below, the functional group may be introduced into any of a side chain, one end, both ends, and a side chain both ends type. The side chain type represented by the general formula (12) is obtained by introducing an organic modifying group into the side chain of polysiloxane. The single terminal type represented by the general formula (13) is obtained by introducing an organic modifying group into one terminal of polysiloxane. The both-end type represented by the general formula (14) is obtained by introducing an organic modifying group at both ends of the polysiloxane. The side chain double-end type represented by the general formula (15) is one in which organic modifying groups are introduced into both the side chain and both ends of the polysiloxane.

In the general formulas (12) to (15), R ₃ means an organic modifying group having an amino group or an epoxy group shown below, and R ₃ ′ means a hydrocarbon group, which is an average number of repetitions. m ₂ and n ₂ each represent a number of 1 to 20, preferably 5 to 15.

［ここで、アミノ基、エポキシ基に結合する基Ｒ_４としては、例えばプロピル基、ブチル基、フェニル基、フェニルメチルエーテル基などが挙げられる］

[Examples of the group R ₄ bonded to an amino group or an epoxy group include a propyl group, a butyl group, a phenyl group, and a phenylmethyl ether group]

  Examples of the main chain siloxane skeleton include dimethylsiloxane, diphenylsiloxane, and methylphenylsiloxane. The molecular weight of silicone is preferably 800 or less, more preferably 500 or less per functional group.

  Examples of such modified silicones include diaminopropylpolydimethylsiloxane, diaminopropylpolydiphenylsiloxane, diglycidoxypropylpropylpolydimethylsiloxane, diglycidoxypropylpropylpolydiphenylsiloxane, and the like.

  As the amino-modified silicone, diaminosiloxane represented by the following general formula (16) is preferably used as the diaminosiloxane having both ends.

［但し、Ａｒ_５及びＡｒ_６は、それぞれ、酸素原子を含有していてもよい２価の有機基を示し、Ｒ_５〜Ｒ_８は、それぞれ炭素数１〜６の炭化水素基を示し、平均繰り返し数であるｍ_３は、１〜２０、好ましくは５〜１５の数を意味する。

[However, Ar ₅ and Ar ₆ each represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, and average M ₃ which is a repeating number means a number of 1 to 20, preferably 5 to 15.

As a specific example of the diaminosiloxane represented by the general formula (16), a diaminosiloxane represented by the following formula is preferable. In the following formula, m ₃ has the same meaning as described above.

  Typical solvents for the solution containing the modified silicone (resist ink 5a) include, for example, ether solvents such as tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, acetone, MEK (methyl ethyl ketone), 2-pentanone, 3 Examples thereof include ketone solvents such as pentanone and γ-butyrolactone, and aromatic hydrocarbon solvents such as toluene and xylene. These may be used alone or in combination of several kinds. Particularly preferred is toluene. The concentration of the modified silicone in the solution containing the terminal modified silicone (resist ink 5a) is preferably 0.1 to 5% by weight, and more preferably 0.5 to 1% by weight.

<Silane coupling agent>
Examples of the silane coupling agent having an amino group as an organic functional group include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, etc. Can be mentioned. These can be used alone or in combination of two or more.

  Examples of the silane coupling agent having an epoxy group as an organic functional group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidide. Examples include xylpropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like. These can be used alone or in combination of two or more.

  Among these, 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane are particularly preferable.

  The silane coupling agent is used as an organic solvent solution (resist ink 5a). The organic solvent is not particularly limited as long as it is a liquid that can dissolve the silane coupling agent. Examples of such an organic solvent include alcohol solvents such as methanol, ethanol, propanol, and isopropanol, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, Amide solvents such as N, N-dimethylmethoxyacetamide, dimethyl sulfoxide and N-methyl-2-pyrrolidone, ether solvents such as tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether and dioxane, acetone, MEK (methyl ethyl ketone), 2-pentanone And ketone solvents such as 3-pentanone and γ-butyrolactone, and aromatic hydrocarbon solvents such as toluene and xylene. The concentration of the silane coupling agent in the solution containing the silane coupling agent (resist ink 5a) is preferably 0.1 to 5% by weight, and more preferably 0.5 to 1% by weight.

<Epoxy oligomer>
The epoxy oligomer used in the present invention is not particularly limited, and examples thereof include epoxy oligomers such as bisphenol A type, bisphenol F type, biphenyl type, and cresol novolac type. These may be used alone or in combination of two or more. Can be used. The epoxy oligomer preferably has an epoxy equivalent of 800 or less, and more preferably 500 or less.

  Typical solvents for the solution containing the epoxy oligomer (resist ink 5a) include, for example, alcohol solvents such as methanol, ethanol, propanol, isopropanol, N, N-dimethylformamide, N, N-diethylformamide, N, Amide solvents such as N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, ethers such as tetrahydrofuran, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane Solvent, ketone solvents such as acetone, MEK (methyl ethyl ketone), 2-pentanone, 3-pentanone, and γ-butyrolactone, and aromatic hydrocarbon solvents such as toluene and xylene It can be mentioned. Among these, toluene is particularly preferable. These solvents may be used alone or in combination of several kinds. The concentration of the epoxy oligomer in the solution containing the epoxy oligomer (resist ink 5a) is preferably 0.1 to 5% by weight, and more preferably 0.5 to 1% by weight.

  In addition to the solute and the solvent, for example, a polymer component such as polystyrene or acrylic resin can be blended with the resist ink 5a for the purpose of adjusting the viscosity of the resist ink 5a and the volatility of the solvent. Further, the viscosity of the resist ink 5a is preferably about 0.2 to 5 cP from the viewpoint of maintaining the adhesion to the mold 10 and the accuracy of the pattern when adhered to the metal ion-containing layer 3a. .

  Examples of the method of attaching the resist ink 5a having the above configuration to the mold 10 include a method of bringing the pattern-shaped surface 10a of the mold 10 into contact with a porous body impregnated with the resist ink 5a, and a pattern-shaped surface of the mold 10 A method of immersing 10a in the resist ink 5a, a method of spraying the resist ink 5a on the pattern-shaped surface 10a of the mold 10, and a method of transferring the resist ink 5a coated with a thin film on a smooth substrate to the pattern-shaped surface 10a of the mold 10 Can be adopted.

[Resist pattern formation]
Next, as shown in FIG. 1 and FIG. 2 (d), the resist ink 5a is adhered to the surface of the metal ion-containing layer 3a by bringing the pattern-shaped surface 10a of the mold 10 with the resist ink 5a into contact therewith. A resist mask 5 to which the shape is transferred is formed (step S4). That is, a fine pattern is printed using the resist ink 5a. In printing, from the viewpoint of uniformly attaching the resist ink 5a to the surface of the metal ion-containing layer 3a, the pattern-shaped surface 10a of the mold 10 is brought into contact with the surface of the metal ion-containing layer 3a at a predetermined pressure, for example, about 100 to 1000 Pa. It is preferable. Further, from the same viewpoint as described above, after printing the resist ink 5a on the surface of the metal ion-containing layer 3a, after volatilizing the solvent at room temperature, the mold 10 is brought into contact with the resist ink 5a so that the pattern does not shift. It is also preferable to repeat the printing with reattachment.

  The drying method for fixing the resist ink 5a containing the terminal-modified silicone, the silane coupling agent or the epoxy oligomer after printing is not particularly limited, and natural drying, spray drying with an air gun, drying with an oven, or the like can be used. Can be used. The drying conditions depend on the type of polar solvent, but are 10 to 150 ° C. for 5 seconds to 60 minutes, preferably 25 to 150 ° C. for 10 seconds to 30 minutes, more preferably 30 to 120 ° C. for 1 minute to 10 minutes. It is.

  The resist pattern formed on the surface of the metal ion-containing layer 3a has a mask region (i.e., circuit wiring 9) in addition to the function of suppressing metal deposition in the portion covered with the resist mask 5 in the next metal deposition layer forming step. It also has a function of fixing the surface insulation resistance between the wirings by fixing to the resin surface between them. In addition, the constituent components of the resist mask 5 are chemically bonded to the resin in a state of being partially impregnated on the resin surface, so that they have heat resistance, unlike the photosensitive resist material generally used in photolithography, The process of peeling off in the subsequent processes can be omitted.

[Metal precipitation layer formation]
Next, in the method for manufacturing a circuit board according to the present embodiment, the metal ions in the metal ion-containing layer 3a are reduced and masked with the resist mask 5 as shown in FIGS. 1 and 2 (e). A metal deposition layer 7 is formed in the exposed region that is not exposed (step S5). As the reduction treatment method, it is particularly advantageous to use a wet reduction method. The wet reduction method is a method for reducing metal ions in an exposed region not masked by the resist mask 5 by immersing the metal ion-containing layer 3a in a solution containing a reducing agent (reducing agent solution). . In this wet reduction method, metal ions existing inside the metal ion-containing layer 3a (for example, a deep layer portion deeper than the surface layer portion or a coating portion directly under the resist mask 5) are reduced and deposited as metal at that location. This is an effective method capable of preferentially performing metal deposition in the surface layer portion of the metal ion-containing layer 3a while suppressing the occurrence of the metal ion. Further, in the wet reduction method, there is little unevenness of metal deposition, and it is possible to form a uniform metal deposition layer 7 in a short time.

  In addition, in the metal ion containing layer 3a using the polyimide precursor resin layer 3 obtained via the method B (that is, the method of applying the polyimide precursor resin solution), the thickness of the polyimide precursor resin layer 3 is Since it is easy to ensure sufficiently, the amount of metal ions that can be impregnated in the resin layer (that is, the content of metal ions in the resin layer) can be greatly increased. As a result, the metal deposited layer 7 obtained in the metal deposited layer forming step (step S5) can be formed into a film shape, so that an electroless plating step described later can be omitted. Electroless plating has the problem of complicated plating solution management and waste liquid treatment, so if circuit wiring with excellent adhesion to the substrate can be formed without using electroless plating, the industry The target value is very large. From such a viewpoint, it is particularly preferable to employ a combination in which the polyimide precursor resin layer 3 is formed by the method B and the metal deposition layer forming step is performed by a wet reduction method.

  As the reducing agent, for example, boron compounds such as sodium borohydride, potassium borohydride, dimethylamine borane and the like are preferable. These boron compounds can be used in the form of a solution (reducing agent solution) of sodium hypophosphite, formalin, hydrazines, 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. When the concentration of the boron compound in the reducing agent solution is less than 0.005 mol / L, reduction of the metal ions contained in the metal ion-containing layer 3a may be insufficient, and when the concentration exceeds 0.1 mol / L, the boron compound As a result, the polyimide precursor resin may be dissolved.

  In the wet reduction treatment, the region not masked by the resist mask 5 is placed in a reducing agent solution at a temperature in the range of 10 to 90 ° C., preferably in the range of 50 to 70 ° C., for 20 seconds to 30 minutes. The immersion is preferably performed for 30 seconds to 10 minutes, more preferably for 1 minute to 5 minutes. By soaking, metal ions in the metal ion-containing layer 3a are reduced by the action of the reducing agent, and the metal is deposited in the form of particles at the surface layer portion of the metal ion-containing layer 3a. At the end point of the reduction, the metal precursor hardly exists in the polyimide precursor resin other than the exposed surface layer portion of the metal ion-containing layer 3a (for example, the deep layer portion or the coating portion immediately below the resist mask 5). As the metal deposits on the surface layer portion, the metal ions in the metal ion-containing layer 3a move to the surface layer portion of the unmasked region of the metal ion-containing layer 3a while maintaining a uniform concentration distribution, It is considered that the moved metal ions are reduced in the vicinity of the surface layer portion to cause metal precipitation. At the end of the reduction, the metal ions hardly remain in the polyimide precursor resin layer 3, but even if metal ions remain in the polyimide precursor resin layer 3, they remain due to the acid treatment described later. Metal ions can be removed. For determining the end point of reduction, for example, the cross section of the metal ion-containing layer 3a (polyimide precursor resin layer 3) is measured using an energy dispersive X-ray (EDX) analyzer, and the atomic weight of the remaining metal ions is measured. It can be confirmed by reading%.

  In the present embodiment, in the metal deposition layer forming step, the metal deposition layer 7 that becomes the seed layer of the circuit wiring 9 is formed only in a portion not covered with the patterned resist mask 5, and the lower portion of the resist mask 5 is formed. Therefore, a flash etching process for finally removing the seed layer is not necessary, and it is possible to reduce the number of processes and improve the reliability of the circuit wiring board.

[Circuit wiring formation]
Next, as shown in FIGS. 1 and 2 (f), a circuit wiring 9 having a pattern is formed on the metal deposition layer 7 by electroless plating and / or electroplating (step S6). Electroless plating is performed by immersing the polyimide precursor resin layer 3 on which the metal deposit layer 7 is formed in an electroless plating solution (electroless plating step). By this electroless plating, an electroless plating layer is formed. This electroless plating layer becomes the core of electroplating performed later.

  As the electroless plating solution used in the electroless plating process, a neutral to weakly acidic hypophosphorous acid nickel plating solution or boron-based nickel plating solution is selected in consideration of the influence on the polyimide precursor resin. It is preferable. As a commercially available product of a hypophosphorous acid nickel plating solution, for example, Top Nicolon (trade name; manufactured by Okuno Pharmaceutical Co., Ltd.) can be mentioned. 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. Moreover, it is preferable to adjust the pH of the electroless plating solution to neutral to slightly acidic 4-7. 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, and weak acids such as boric acid, carbonic acid, acetic acid and citric acid, and these These alkali salts may be combined to provide a buffering action. The temperature of the electroless plating treatment can be in the range of 80 to 95 ° C, and preferably in the range of 85 to 90 ° C. Moreover, the processing temperature of an electroless-plating process can be made into 20 second-10 minutes, Preferably it is 30 second-5 minutes, More preferably, it is 1 minute-3 minutes.

Next, electroplating is performed using the metal deposition layer 7 or the electroless plating layer as a nucleus to form an electroplating layer (electroplating step). An electroplating layer is formed by electroplating so as to cover the electroless plating layer. In electroplating, for example, in a plating solution having a composition containing sulfuric acid, copper sulfate, hydrochloric acid, and a brightener [for example, McCuispec (trade name) manufactured by Nihon McDermitt as a commercial product], an electroless plating layer is used as a cathode, A metal such as Cu is used as an 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.

  As described above, the circuit wiring 9 can be formed while omitting the electroless plating step by optimizing the method for forming the polyimide precursor resin layer 3 and the reduction method in the metal deposition layer forming step. is there.

  In the present embodiment, it is not necessary to remove the resist mask 5 even after the circuit wiring 9 having a pattern is formed. The constituent components of the resist mask 5 are partly impregnated on the surface of the polyimide resin, chemically bonded to the polyimide resin, and become a part of the inter-wiring insulating layer of the circuit wiring 9. The component is fixed to the mask region (that is, the surface of the polyimide resin between the circuit wirings 9) and has a function of increasing the surface insulation resistance between the circuit wirings 9, so that the leakage current between the circuit wirings 9 is reduced. Generation can be suppressed.

  Here, the removal of the metal ions in the polyimide precursor resin layer 3 will be described. In the wet reduction treatment, for example, when a metal salt such as sodium borohydride, potassium borohydride, dimethylamine borane or the like is used, metal ions derived from the metal salt may be present in the polyimide precursor resin layer 3. Therefore, it is preferable to remove this. The removal of metal ions is preferably performed by immersing in an aqueous solution of acid, and the applicable acid in this case dissociates the metal ions coordinated with the carboxyl groups of the polyamic acid. It is preferable to select a strong 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 metal deposition layer 7, and acetic acid (pKa = 4.56) is not preferable because the strength of the acid is low and it is difficult to remove metal ions. . As conditions for the immersion treatment for removing metal ions, an aqueous acid solution having a concentration in the range of 1 to 15% by weight, preferably in the range of 5 to 10% by weight and in the range of 20 to 50 ° C., It is preferable to immerse in the range of 2 to 10 minutes. By performing such an acid treatment, metal ions remaining in the polyimide precursor resin layer 3 can be simultaneously removed after the reduction is completed. The method for removing metal ions is also disclosed in, for example, “17th Microelectronics Symposium Proceedings”, September 2007, pages 179-182.

[Imidation]
Next, as shown in FIGS. 1 and 2 (g), the polyimide precursor resin layer 3 is imidized by heat treatment to form a polyimide resin layer 3b (step S7). The imidization method is not particularly limited, and for example, heat treatment such as heating for 1 to 60 minutes under a temperature condition in the range of 80 to 400 ° C. is suitably employed. In order to suppress the oxidation of the circuit wiring 9, which is a metal layer formed by reduction and plating, heat treatment in a low oxygen atmosphere is preferable. Specifically, in an inert gas atmosphere such as nitrogen or a rare gas, hydrogen or the like It is preferably performed in a reducing gas atmosphere or in a vacuum. Further, the imidization process of step S7 is preferably performed after the circuit wiring formation process of step S6, but there is no problem even if it is performed before the process of step S6.

  In the above steps, the base layer 1 is not necessarily used. Further, in any step after step S2, the polyimide precursor resin layer 3, the metal ion impregnated layer 3a or the polyimide resin layer 3b may be peeled off from the base layer 1 and the processing may be performed without the base layer 1 being provided. .

  In the present embodiment, since the polyimide precursor resin layer 3 is impregnated with metal ions (step S2) and then the resist mask 5 is formed (steps S3 and S4), the polyimide precursor resin layer is formed. 3 can be impregnated with metal ions. Therefore, since the amount of metal ions contained in the metal ion-containing layer 3a is large and the metal deposition layer 7 after the reduction treatment can be formed thick, electroplating in the wiring forming process in step S6 is facilitated. Moreover, since the metal deposition layer 7 plays a role as a diffusion barrier film of metal ions (copper ions) used for the wiring material, the barrier function can be improved by forming the metal deposition layer 7 thick. . Generally, it is said that the adhesiveness between the wiring (circuit wiring 9) and the substrate (polyimide resin layer 3b) in the printed wiring board is lowered by diffusion of metal ions (copper ions) used for the wiring material. Therefore, it is advantageous to apply the process of the present embodiment that can sufficiently thicken the metal deposition layer 7 as the diffusion barrier film in an application that requires high adhesion durability such as a flexible wiring board. is there.

  From another point of view, the manufacturing method of the present invention eliminates the steps such as the etching of the metal seed layer and the removal of the photosensitive resist in the conventional method, so that the wiring width of 25 μm or less, which has been considered difficult until now, is not required. In the production of a flexible wiring board that is effective for wiring formation but particularly requires high adhesion durability, the circuit wiring board of the present embodiment in which the polyimide precursor resin layer 3 is first impregnated with metal ions is used. It is advantageous to apply a manufacturing method.

  According to the method for manufacturing a circuit wiring board of the present embodiment, the circuit wiring 9 having excellent adhesion is formed on the insulating resin layer having the polyimide resin layer 3b by the above steps S1 to S7. The circuit wiring board 100 can be manufactured. In this method, the resist ink 5a is adhered by bringing the pattern-shaped surface 10a of the mold 10 with the resist ink 5a into contact with the surface of the polyimide precursor resin layer 3 (metal ion-containing layer 3a) containing metal ions. It was adopted. Therefore, the resist mask 5 can be easily formed with a small number of steps without the need for a photolithography technique as in the prior art, and an etching step for removing the metal seed layer and a step for removing the photosensitive resist are also possible. Since it is unnecessary, the number of processes can be greatly reduced. Therefore, the method of the present invention has a great industrial utility value.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4 as appropriate. FIG. 3 is a flowchart showing main process steps of the circuit wiring board manufacturing method according to the present embodiment, and FIG. 4 is an explanatory diagram of each process. In the following description, the description will focus on differences from the circuit wiring board manufacturing method according to the first embodiment.

  As shown in FIG. 3, the circuit wiring board manufacturing method according to the present embodiment includes steps S11 to S17. In the circuit wiring board manufacturing method of the first embodiment, the polyimide precursor resin layer 3 is impregnated with metal ions, and then the resist mask 5 is formed by contacting the mold 10 with the resist ink 5a attached to the surface thereof. However, in this embodiment, the resist mask 5 is formed on the surface of the polyimide precursor resin layer 3 and then impregnated with metal ions.

  That is, in this embodiment, first, as shown in FIG. 4A, the polyimide precursor resin layer 3 is formed on the base layer 1 (step S11). Next, as shown in FIG. 4B, the mold 10 is prepared in which the resist ink 5a adheres to the concavo-convex pattern shape surface 10a (step S12). Next, as shown in FIG. 4C, the resist ink 5a is adhered to the surface of the polyimide precursor resin layer 3 by bringing the pattern shape surface 10a of the mold 10 with the resist ink 5a into contact therewith, thereby forming the pattern shape. A resist mask 5 to which is transferred is formed (step S13). Next, as shown in FIG. 4D, the polyimide precursor resin layer 3 on which the resist mask 5 is formed is impregnated with a metal ion solution and then dried to obtain metal ions containing metal ions. The containing layer 3a is formed (step S14). Since each process of said step S11-step S14 can be implemented according to 1st Embodiment, the description regarding the content of each process is abbreviate | omitted here.

  Also, the following steps S15 (metal deposition layer formation), step S16 (circuit wiring formation), and step S17 (imidization) [FIG. 4 (e) to (g)] are also described in the first embodiment. The explanation is omitted because it is exactly the same.

  In this embodiment, since the polyimide precursor resin layer 3 on which the resist mask 5 is formed is impregnated with the metal ion solution, it is difficult for the mask coating portion to be impregnated with metal ions. As a result, there is little residual metal ions in the polyimide resin layer 3b between the circuit wires 9, and the insulation between the circuit wires 9 can be improved. In general, it is said that the insulation reliability between wirings (circuit wirings 9) in a printed wiring board is lowered by carboxylic acid forming metal ions and ion pairs remaining on the resin surface between the wirings and inside. Therefore, in the manufacture of ultra-fine wiring with a wiring interval of 3 μm or less, which requires high insulation reliability, the process of the present embodiment is applied in which the residual metal ions are particularly small between the wirings and the insulating properties between the wirings are particularly good. It is advantageous to do so.

  Other configurations and effects in the method of manufacturing the circuit wiring board according to the present embodiment are the same as those in the first embodiment.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples. Unless otherwise specified in the examples of the present invention, various measurements and evaluations are as follows. Further, the abbreviations used in this example are as described above.

[Evaluation of adhesion]
The adhesion was evaluated by preparing a test piece for measuring circuit wiring having a width of 100 μm and measuring the peel strength in a 90 ° direction at room temperature using a strograph-M1 (manufactured by Toyo Seiki Seisakusho). . In addition, regarding the adhesion, when the peel strength is 0.5 kN / m or more and less than 1.0 kN / m, “no problem in practicality”, and when it is 1.0 kN / m or more, “excellent”. It was evaluated.

[Measurement of linear thermal expansion coefficient]
The coefficient of linear thermal expansion was determined by using a thermomechanical analyzer (manufactured by Seiko Instruments Inc.), raising the temperature of the sample to 250 ° C., holding the sample at that temperature for 10 minutes, and then cooling at a rate of 5 ° C./min. To an average linear thermal expansion coefficient (CTE) from 100 ° C to 100 ° C.

[Measurement of glass transition temperature]
The glass transition temperature was measured at a rate of 10 ° C./min from room temperature to 400 ° C. while applying a 1 Hz vibration using a 10 mm wide sample using a viscoelasticity analyzer (RSA-II manufactured by Rheometric Science Effy Co., Ltd.). It was determined from the maximum loss tangent (Tan δ) when the temperature was raised at.

[Measurement of treatment layer thickness with alkaline aqueous solution]
The cross section of the sample was observed using a scanning transmission electron microscope (manufactured by Hitachi High-Technologies Corporation), and the thickness of the treatment layer with an alkaline aqueous solution was confirmed.

[Measurement of sheet resistance of metal layer]
The sheet resistance of the metal layer was measured by a method based on JIS K 7194 using a resistivity meter (MCP-T610 manufactured by Mitsubishi Chemical Corporation). In addition, when the measured value of the sheet resistance of the metal layer exceeds 50Ω / □ (ohm / square), the level is “difficult electroplating”, and when it is 50Ω / □ or less, the level is “possible electroplating”. It was evaluated. Moreover, when it was 30 Ω / □ or less, the metal layer was evaluated as “particularly excellent” as a conductive film.

[Evaluation method of warpage]
The conductor layer forming resin film is cut by a cutting machine to create a sheet of 10 cm × 10 cm size, and when the sheet is placed on the desk, the height from the desk surface of the part that is the most lifted from the desk surface is set. Measured using calipers. The height was defined as the amount of warpage of the conductor layer-forming resin film.

Production Example 1
In a 500 ml separable flask, 20.7 g of 2′-methoxy-4,4′-diaminobenzanilide (0.08 mol) was dissolved in 343 g of DMAc with stirring. Next, 28.5 g PMDA (0.13 mol) and 10.3 g DAPE44 (0.05 mol) were added to the solution in a nitrogen stream. Thereafter, polymerization reaction was continued to stir for about 3 hours to obtain a viscous polyimide precursor resin solution S _1.

The resulting polyimide precursor resin solution S ₁ was applied on a stainless steel substrate, and dried 5 minutes at 130 ° C., to complete the over 15 minutes allowed to warm to 360 ° C. imidization, the stainless steel substrate A laminated polyimide film was obtained. The polyimide film was peeled from the stainless steel substrate, to obtain a polyimide film S ₂ of 25μm in thickness. Linear thermal expansion coefficient of the polyimide film _{S 2} was ^{14.6 × 10 -6 (1 / K} ).

Production Example 2
In a 500 ml separable flask, 29.5 g APB (0.1 mol) was dissolved in 367 g DMAc with stirring. Next, 9.1 g PMDA (0.04 mol) and 20.2 g BTDA (0.06 mol) were added to the solution under a nitrogen stream. Thereafter, polymerization reaction was continued to stir for about 3 hours to obtain a viscous polyimide precursor resin liquid T _1.

The resulting polyimide precursor resin solution T ₁ was coated on a stainless steel substrate and dried for 5 minutes at 130 ° C.. Thereafter, the coating film was heated to 360 ° C. over 15 minutes to complete imidization, and the substrate was removed to obtain a polyimide film T ₂ having a thickness of 12 μm. The glass transition temperature of the resulting polyimide film T ₂ are was 218 ° C..

Production Example 3
A test piece 12.5 cm × 12.5 cm (thickness 0.7 mm) of alkali-free glass (Asahi Glass Co., Ltd. AN-100) was treated with a 5N sodium hydroxide aqueous solution at 50 ° C. for 5 minutes. Next, the glass substrate of the test piece was washed with pure water and dried, and then immersed in a 1 wt% aqueous solution of 3-aminopropyltrimethoxysilane (hereinafter abbreviated as “γ-APS”). The glass substrate was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes to obtain a glass substrate G.

[Example 1]
50 polyimide film (manufactured by Toray DuPont, trade name: Kapton EN, 100 mm × 100 mm × 25 μm thickness, linear thermal expansion coefficient (CTE) 16 × 10 ⁻⁶ / K) in 5N potassium hydroxide aqueous solution Immersion at 10 ° C. for 10 minutes. Thereafter, the immersed polyimide film is sufficiently washed with ion-exchanged water, immersed in a 1% by weight hydrochloric acid aqueous solution (25 ° C.) for 30 seconds, further sufficiently washed with ion-exchanged water, and dried by blowing compressed air. Thus, a surface-treated polyimide film a1 was obtained. The thickness of the alkali treatment layer on one surface of this surface-treated polyimide film a1 was 1.4 μm.

  Next, the surface-treated polyimide film a1 is immersed in a mixed aqueous solution (25 ° C.) of 100 mM nickel acetate-600 mM ammonia for 10 minutes, and the alkali-treated layer is impregnated with nickel ions to form an impregnated layer (metal ion-containing layer). did.

  PDMS (commonly known as silicone rubber) is added to a membrane filter (nitrocellulose membrane filter, pore size 0.22 μm, manufactured by MILLIPORE) impregnated with 1% toluene solution of diaminopropyl-polydimethylsiloxane (KF8010 manufactured by Shin-Etsu Chemical Co., Ltd.) as an ink. Ink adheres to the surface of the concavo-convex pattern by stamping the manufactured concavo-convex pattern (depth of the recess; 5 μm, pattern shape; wiring width / wiring interval (L / S) = 5 μm / 5 μm, pattern area: 1 square cm) I let you. After drying the concavo-convex pattern with ink attached for 1 minute (room temperature 23 ° C., humidity 50%), the surface of the concavo-convex pattern surface is re-stamped on the surface of the surface-treated polyimide film a1 impregnated with the above nickel ions. The film was transferred onto the surface of the treated polyimide film a1 and subsequently heat treated at 130 ° C. for 5 minutes to obtain a film b1 having a mask pattern formed on the surface of the surface treated polyimide film a1.

The film b1 was immersed in a 10 mM aqueous solution of sodium borohydride (30 ° C.) for 2 minutes to form a nickel deposition layer on the surface of the impregnation layer in a region not masked with the ink layer, thereby obtaining a nickel deposition film c1. . It was 1500 ohms / square as a result of measuring the sheet resistance of this nickel precipitation film c1. Next, this film c1 is immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd., trade name: Top Nicolon TOM-S) at a temperature of 80 ° C. for 30 seconds, thereby providing a base for electrolytic copper plating. A nickel layer was formed. Here, the sheet resistance of the nickel layer formed by electroless nickel plating was 15Ω / □. Further, the formed nickel layer is electroplated at a current density of 0.5 A / dm ^{2 in} an electric copper plating bath to form a copper wiring having a copper film thickness of 3 μm, thereby obtaining a copper wiring forming film d1. It was.

  Residual metal ions were removed by immersing the obtained copper wiring forming film d1 in a 10 wt% oxalic acid aqueous solution (25 ° C.) for 2 minutes.

  After the copper wiring forming film d1 was washed with ion exchange water, it was heated to 300 ° C. in a nitrogen atmosphere, and the polyimide precursor resin was imidized at the same temperature for 5 minutes. Then, it cooled to normal temperature in nitrogen atmosphere, and obtained the copper wiring formation film e1. The obtained copper wiring formation film e1 had no warp and had a copper wiring peeling strength of 0.6 kN / m, and there was no problem in adhesion.

[Example 2]
On a stainless steel substrate, the thickness after imidization by applying a polyimide precursor resin solution S ₁ so that 25 [mu] m, followed by drying at 130 ° C. 20 minutes to obtain a polyimide precursor resin layer a2.

  Instead of the surface-treated polyimide film a1 in Example 1, a polyimide precursor resin layer b2 on which a resist pattern was formed, a nickel-deposited resin layer, as in Example 1, except that a polyimide precursor resin layer a2 was used. c2, the copper wiring formation resin layer d2, and the copper wiring formation resin layer e2 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c2 was 25Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e2 was peeled from the stainless steel base material to obtain a copper wiring formation film e2 '. The obtained copper wiring forming film e2 'had no warp, the peel strength of the copper wiring was 0.6 kN / m, and there was no problem in adhesion.

[Example 3]
On the glass substrate G, thickness after imidization by applying a polyimide precursor resin solution T ₁ so that the 5 [mu] m, followed by drying at 130 ° C. 20 minutes to obtain a polyimide precursor resin layer a3.

Instead of the surface-treated polyimide film a1 in Example 1, a polyimide precursor resin layer b3 on which a resist pattern was formed, a nickel-deposited resin layer in the same manner as in Example 1, except that a polyimide precursor resin layer a3 was used. c3, a copper wiring forming resin layer d3 and a copper wiring forming resin layer e3 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c3 was 50Ω / □, and electroless plating could be omitted, so that electroplating was possible. The obtained copper wiring forming resin layer e3 had a copper wiring peeling strength of 0.9 kN / m, and there was no problem in adhesion.

[Example 4]
On a stainless steel substrate, a polyimide precursor resin solution S ₁ so that the thickness after imidization is 25μm was coated and dried at 130 ° C. 20 min. Further thereon, a polyimide precursor resin solution T ₁ so that the thickness after imidization is 5μm was applied, and dried at 130 ° C. 20 minutes to obtain a polyimide precursor resin layer a4.

  A polyimide precursor resin layer b4 on which a resist pattern is formed, a nickel deposition resin layer, in the same manner as in Example 1, except that a polyimide precursor resin layer a4 is used instead of the surface-treated polyimide film a1 in Example 1. c4, copper wiring formation resin layer d4, and copper wiring formation resin layer e4 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c4 was 20Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e4 was peeled from the stainless steel base material to obtain a copper wiring formation film e4 '. The obtained copper wiring forming film e4 'was not warped, the peel strength of the copper wiring was 1.0 kN / m, and the adhesion was excellent.

[Example 5]
The polyimide precursor resin layer a5 and the polyimide precursor were the same as in Example 4 except that a 1 wt% toluene solution of aminopropyl-triethoxysilane (KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the ink. A resin layer b5, a nickel-deposited resin layer c5, a copper wiring forming resin layer d5, and a copper wiring forming resin layer e5 were obtained. In addition, since the sheet resistance of the nickel precipitation resin layer c5 was 20Ω / □ and was particularly excellent as a metal film, it was possible to omit electroless nickel plating and directly perform electroplating. The obtained copper wiring formation resin layer e5 was peeled from the stainless steel base material to obtain a copper wiring formation film e5 ′. The obtained copper wiring formation film e5 ′ had no warp, the copper wiring peel strength was 1.0 kN / m, and the adhesion was excellent.

[Example 6]
The polyimide precursor resin layer a6, the polyimide precursor resin layer b6, and nickel were used in the same manner as in Example 4 except that a 1 wt% toluene solution of an epoxy oligomer (ZX-1059 manufactured by Toto Kasei Co., Ltd.) was used as the ink. A precipitated resin layer c6, a copper wiring forming resin layer d6 and a copper wiring forming resin layer e6 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c6 was 20Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e6 was peeled from the stainless steel base material to obtain a copper wiring formation film e6 ′. The obtained copper wiring forming film e6 ′ had no warp, the copper wiring peeling strength was 1.0 kN / m, and the adhesion was excellent.

[Example 7]
In the same manner as in Example 1, a surface-treated polyimide film a7 was obtained.

  PDMS (commonly known as silicone rubber) is added to a membrane filter (nitrocellulose membrane filter, pore size 0.22 μm, manufactured by MILLIPORE) impregnated with 1% toluene solution of diaminopropyl-polydimethylsiloxane (KF8010 manufactured by Shin-Etsu Chemical Co., Ltd.) as an ink. Ink adheres to the surface of the concavo-convex pattern by stamping the manufactured concavo-convex pattern (recess depth: 2 μm, pattern shape; wiring width / interval (L / S) = 2 μm / 2 μm, pattern area: 1 square cm) I let you. After drying the concavo-convex pattern with ink attached for 1 minute (room temperature 23 ° C., humidity 50%), the surface of the concavo-convex pattern surface is transferred to the surface of the surface-treated polyimide film a7 by stamping again on the surface of the surface-treated polyimide film a7. And subsequently heat treated at 130 ° C. for 5 minutes to obtain a film b7 having a mask pattern formed on the surface of the surface-treated polyimide film a7.

  Next, the film b7 on which the mask pattern is formed is immersed in a mixed aqueous solution (25 ° C.) of 100 mM nickel acetate-600 mM ammonia for 10 minutes to form a film b7 ′ in which a mask pattern is formed and impregnated with nickel ions. did.

The film b7 ′ is immersed in a 10 mM aqueous solution of sodium borohydride (30 ° C.) for 2 minutes to form a nickel deposition layer on the surface of the impregnation layer in a region not masked with the ink layer, thereby obtaining a nickel deposition film c7. It was. As a result of measuring the sheet resistance of this nickel deposit film c7, it was about 3000Ω / □. Next, this film c7 is immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd., trade name: Top Nicolone TOM-S) at a temperature of 80 ° C. for 30 seconds to become a base for electrolytic copper plating. A nickel layer was formed. Here, the sheet resistance of the nickel layer formed by electroless nickel plating was 15Ω / □. Further, the formed nickel layer is electroplated at a current density of 0.5 A / dm ^{2 in} an electric copper plating bath to form a copper wiring having a copper film thickness of 3 μm, thereby obtaining a copper wiring forming film d7. It was.

  Residual metal ions were removed by immersing the obtained copper wiring forming film d7 in a 10 wt% oxalic acid aqueous solution (25 ° C.) for 2 minutes.

  After washing the copper wiring forming film d7 with ion exchange water, it was heated to 300 ° C. in a nitrogen atmosphere, and the polyimide precursor resin was imidized at the same temperature for 5 minutes. Then, it cooled to normal temperature in nitrogen atmosphere, and obtained the copper wiring formation film e7. The obtained copper wiring forming film e7 had no warp and had a copper wiring peeling strength of 0.5 kN / m, and there was no problem in adhesion.

[Example 8]
In the same manner as in Example 2, a polyimide precursor resin layer a8 was obtained.

  A polyimide precursor resin layer b8 on which a resist pattern is formed and a mask pattern are formed in the same manner as in Example 7, except that a polyimide precursor resin layer a8 is used instead of the surface-treated polyimide film a7 in Example 7. Further, a film b8 ′ impregnated with nickel ions, a nickel-deposited resin layer c8, a copper wiring forming resin layer d8, and a copper wiring forming resin layer e8 were obtained. The sheet resistance of the nickel-deposited resin layer c8 was 30Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e8 was peeled from the stainless steel base material to obtain a copper wiring formation film e8 '. The obtained copper wiring forming film e8 'had no warp, the peel strength of the copper wiring was 0.5 kN / m, and there was no problem in adhesion.

[Example 9]
In the same manner as in Example 3, a polyimide precursor resin layer a9 was obtained.

A polyimide precursor resin layer b9 having a resist pattern formed thereon and a mask pattern are formed in the same manner as in Example 7 except that the polyimide precursor resin layer a9 is used instead of the surface-treated polyimide film a7 in Example 7. Further, a film b9 ′ impregnated with nickel ions, a nickel-deposited resin layer c9, a copper wiring forming resin layer d9, and a copper wiring forming resin layer e9 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c9 was 50Ω / □, and electroless plating could be omitted, so that electroplating was possible. The obtained copper wiring forming resin layer e9 had a copper wiring peeling strength of 0.8 kN / m, and there was no problem in adhesion.

[Example 10]
In the same manner as in Example 4, a polyimide precursor resin layer a10 was obtained.

  A polyimide precursor resin layer b10 on which a resist pattern is formed and a mask pattern are formed in the same manner as in Example 7, except that a polyimide precursor resin layer a10 is used instead of the surface-treated polyimide film a7 in Example 7. Further, a film b10 ′ impregnated with nickel ions, a nickel-deposited resin layer c10, a copper wiring forming resin layer d10, and a copper wiring forming resin layer e10 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c10 was 25Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e10 was peeled from the stainless steel base material to obtain a copper wiring formation film e10 '. The obtained copper wiring forming film e10 'had no warp, the copper wiring peel strength was 0.9 kN / m, and there was no problem in adhesion.

[Example 11]
A polyimide precursor resin layer a11 and a polyimide precursor were used in the same manner as in Example 10 except that a 1 wt% toluene solution of aminopropyl-triethoxysilane (KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the ink. A resin layer b11, a film b11 ′ formed with a mask pattern and impregnated with nickel ions, a nickel-deposited resin layer c11, a copper wiring forming resin layer d11, and a copper wiring forming resin layer e11 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c11 was 25Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e11 was peeled from the stainless steel base material to obtain a copper wiring formation film e11 ′. The obtained copper wiring forming film e11 ′ had no warp and the copper wiring peel strength was 0.9 kN / m, and there was no problem in adhesion.

[Example 12]
The polyimide precursor resin layer a12, the polyimide precursor resin layer b12, and the mask were the same as in Example 10 except that a 1 wt% toluene solution of an epoxy oligomer (ZX-1059 manufactured by Toto Kasei Co., Ltd.) was used as the ink. A film b11 ′ formed with a pattern and impregnated with nickel ions, a nickel-deposited resin layer c12, a copper wiring forming resin layer d12, and a copper wiring forming resin layer e12 were obtained. Note that the sheet resistance of the nickel-deposited resin layer c12 was 25Ω / □ and was particularly excellent as a metal film, so that electroless nickel plating was omitted and direct electroplating was possible. The obtained copper wiring formation resin layer e12 was peeled from the stainless steel base material to obtain a copper wiring formation film e12 ′. The obtained copper wiring forming film e12 ′ had no warp and the copper wiring peeling strength was 0.9 kN / m, and there was no problem in adhesion.

  The outline and test results of the tests of Examples 1 to 6 are summarized in Table 1, and the outline and test results of the tests of Examples 7 to 12 are summarized in Table 2, respectively.

  From Table 1, the copper wiring forming resin layer as the circuit wiring board manufactured by the method of Examples 1 to 12 has a peeling strength of 0.5 kN / m or more, and is used as a flexible printed wiring board or the like. Even so, it was confirmed that the adhesive had no practical problem.

In particular, a polyimide precursor resin solution T _1, a thermoplastic polyimide resin having a glass transition temperature of 350 ° C. or less (Tg = 218 ℃) performed to form a precursor resin layer surface according to Example 3, Example 9 In both cases, the peel strength was 0.8 kN / m or more, indicating sufficient adhesion. This is because the surface layer is formed with the precursor of the thermoplastic polyimide resin, and the metal nickel layer deposited in the metal deposition layer forming step is likely to be embedded in the precursor layer. The reason was considered.

Further, a low thermal expansion polyimide resin having a linear thermal expansion coefficient in the range of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ (1 / K) [CTE = 14.6 × 10 ⁻⁶ (1 / K)]. In Examples 4 to 6 in which the thermoplastic polyimide resin is laminated on top to form a multilayer structure, the thermoplastic polyimide resin is disposed in a layer adjacent to the metal nickel layer, so the same reason as above. Thus, it was shown that very excellent adhesion can be obtained, and the warpage of the substrate can be effectively suppressed by the laminated structure with the low thermal expansion polyimide resin. In addition, Examples 10 to 12 produced by a method according to Examples 4 to 6 also showed a sufficient adhesion with a peel strength of 0.8 kN / m or more.

  Moreover, in Examples 2-6 and 8-12 which employ | adopted method B (method of apply | coating a polyimide precursor resin solution) as a preparation method of a polyimide precursor resin layer, all are the sheets of the nickel deposit layer after a reduction process. The resistance was 50 [Ω / □] or less, and the electroplating process was possible without performing the electroless plating process. By forming a polyimide precursor resin layer with a sufficient thickness, it is possible to increase the amount of nickel ions impregnated in the precursor layer, and the metal nickel layer is formed into a dense film. It was thought that it was made.

  As described above, according to the method for manufacturing a circuit wiring board of the present invention, the circuit wiring and the insulating resin layer can be performed in a simple process without requiring a photolithography process and a seed layer etching process as in the prior art. It was confirmed that a fine fine pitch circuit having high adhesion reliability with (polyimide resin layer) can be formed.

  In addition, this invention is not limited to the said embodiment, A various change is possible within the range of the invention described in the claim.

It is a flowchart which shows the main process procedures of the manufacturing method of the circuit wiring board concerning the 1st Embodiment of this invention. It is explanatory drawing of each process of FIG. It is a flowchart which shows the main process procedures of the manufacturing method of the circuit wiring board concerning the 2nd Embodiment of this invention. It is explanatory drawing of each process of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Underlayer, 3 ... Polyimide precursor resin layer, 3a ... Metal ion containing layer, 3b ... Polyimide resin layer, 5 ... Resist mask, 5a ... Resist ink, 7 ... Metal deposition layer, 9 ... Circuit wiring, 10 ... Mold DESCRIPTION OF SYMBOLS 10a ... Pattern shape surface, 100 ... Circuit wiring board

Claims (5)

A method of manufacturing a circuit wiring board by forming circuit wiring on a polyimide resin layer,
a) a step of preparing a mold with resist ink by attaching resist ink to a pattern shape surface of a mold having a pattern shape;
b) The resist ink is adhered to the surface of the polyimide precursor resin layer including the polyimide resin precursor by bringing the pattern shape surface of the template with the resist ink into contact therewith, and the polyimide precursor resin layer Forming a resist mask patterned on the surface;
c) A step of forming a metal ion-containing polyimide precursor resin layer by impregnating a polyimide precursor resin layer including a polyimide resin precursor with an aqueous solution containing metal ions and drying the polyimide resin resin layer;
d) a step of forming a metal deposition layer by reducing the metal ions in the polyimide precursor resin layer to deposit a metal on a surface layer portion of the polyimide precursor resin in a region not covered with the resist mask;
e) forming a circuit wiring having a pattern on the metal deposition layer by electroless plating and / or electroplating; and
f) imidizing the polyimide precursor resin layer by heat treatment to form the polyimide resin layer;
A method of manufacturing a circuit wiring board, comprising:   2. The method of manufacturing a circuit wiring board according to claim 1, wherein step b) is performed after step c).   2. The method of manufacturing a circuit wiring board according to claim 1, wherein step b) is performed before step c).   The method for producing a circuit wiring board according to claim 1, wherein the polyimide precursor resin layer is formed by treating a surface side of the polyimide resin layer with an alkaline aqueous solution.   The method for producing a circuit wiring board according to claim 1, wherein the polyimide precursor resin layer is formed by applying a polyimide precursor resin solution on a base material and drying.

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