JP2008258293A - Forming method of patterned conductor layer, manufacturing method of circuit board and circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method of a patterned conductor layer capable of forming a minute patterned conductor layer without using metal particles while reducing the number of photolithography steps and etching steps. <P>SOLUTION: The forming method of the patterned conductor layer has a coating film forming step (S1) of coating a coating liquid containing a polyimide precursor resin, a metal compound and a viscosity control agent on the surface of an insulating substrate by using a dispenser, and drying it to form a predetermined coating film; a reducing step (S2) of allowing a reducing agent to act on metal ions in the coating film to reduce the metal ions, and precipitating particle-like metal into the coating film; a non-electrolyte plating step (S3) of executing non-electrolytic plating to the coating film in which the particle-like metal is precipitated to form a non-electrolytic plating layer being a patterned conductor layer; and an imidizing step (S4) of performing heat treatment to imidize the polyimide precursor resin in the coating film, thereby forming a polyimide resin layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for forming a patterned conductor layer for forming a patterned conductor layer serving as a wiring on an insulating base material used for an electronic component, a method for manufacturing a circuit board provided with the patterned conductor layer, and a circuit board.

  As a method for forming a patterned conductor layer on circuit boards used in various electronic components, a conductive metal paste containing fine metal particles such as silver is applied in a predetermined pattern on an insulating substrate. A technique for forming a conductor layer is known. As a method for applying a conductive metal paste to an insulating substrate, Patent Document 1 discloses a conductive material obtained by uniformly dispersing ultrafine metal particles having a fine average particle diameter in a thermosetting resin composition containing an organic solvent. Describes a method of applying a conductive metal paste to a substrate using an inkjet printing technique. In the method of Patent Document 1, after applying the conductive metal paste to the substrate, the metal fine particles are sintered to conduct the coating film, and the thermosetting resin is cured at a temperature of 150 ° C. to 210 ° C. Heat. However, in the method using metal fine particles as in Patent Document 1, if the metal fine particles are not successfully sintered, the patterned conductor layer cannot be conducted, which may adversely affect the electrical characteristics of the electronic component.

  Therefore, as a method for forming a patterned conductor layer without using a conductive paste, Patent Document 2 discloses an electronic component using a polyimide precursor resin solution containing a palladium ion-containing compound, a polyimide precursor resin, and a low molecular organic compound. A method for manufacturing a substrate is described. In the method of Patent Document 1, the polyimide precursor resin solution is applied to a polyimide base material by a bar coater or the like, and then the coating film is dried to form a polyimide precursor metal complex layer. Next, the polyimide precursor metal complex layer is irradiated with ultraviolet rays in the presence of a hydrogen donor to form a plating base nucleus, and then a plating base metal is formed by electroless plating. Furthermore, after forming the electroplating layer by electroplating or before forming the electroplating layer on the plating base metal layer, the polyimide precursor resin is heated and imidized to form a polyimide resin layer.

JP 2002-324966 A JP 2005-154880 A

  The technique described in Patent Document 2 has an advantage that the conductive layer can be formed without being influenced by the sintered state of the metal fine particles because the conductive paste containing the metal fine particles is not used. However, since the technique of Patent Document 2 relates to a method (so-called “solid coating”) in which the entire surface of a polyimide substrate is applied using a bar coater or the like, a polyimide precursor resin is directly formed on the insulating substrate with a fine pattern. The solution cannot be applied. Therefore, in the technique of Patent Document 2, there is a problem that the number of steps increases because the conductor layer after electroplating has to be patterned by photolithography and etching.

  In addition, recently, a patterned conductor layer is applied not only to a plane (two-dimensional surface) but also to an insulating substrate having a three-dimensional surface (three-dimensional surface) that has not been conventionally targeted, such as an uneven surface or a curved surface. There is a need to form. Formation of such a patterned conductor layer on a three-dimensional surface is difficult with the technique of Patent Document 2 in which a conductor layer is formed by a solid coating method and then patterned by photolithography and etching.

  The present invention has been made in view of such problems, and a first object thereof is to form a fine patterned conductor layer without using metal fine particles and while reducing the photolithography process and the etching process. Another object of the present invention is to provide a method for forming a patterned conductor layer that can be used.

  The second object of the present invention is to provide a patterned conductor layer forming method capable of forming a fine patterned conductor layer even on an insulating substrate having a three-dimensional surface such as an uneven surface or a curved surface. Is to provide.

The method for forming the patterned conductor layer of the present invention includes:
A coating film forming step in which a coating liquid containing a polyimide precursor resin, a metal compound, and a viscosity modifier is applied to the surface of the insulating substrate using a dispenser and dried to form a coating film having a predetermined pattern; ,
A reduction step of reducing a metal ion in the coating film by causing a reducing agent to act, and depositing particulate metal on the coating film;
An electroless plating step of forming an electroless plating layer to be a patterned conductor layer by performing electroless plating on the coating film on which the particulate metal is deposited;
An imidization step of performing a heat treatment to imidize the polyimide precursor resin in the coating film to form a polyimide resin layer;
It is equipped with.

  In the present invention, the term “patterned conductor layer” means a conductor layer including an electroless plating layer formed in a predetermined pattern on an insulating base material, and is formed in a predetermined pattern on an insulating base material. In addition, it is used to mean a conductor layer including an electroless plating layer and an electroplating layer.

  In the method for forming a patterned conductor layer of the present invention, the line width of the coating film having the predetermined pattern may be in the range of 10 to 400 μm.

  Moreover, in the formation method of the patterned conductor layer of this invention, the said coating liquid is 5-60 weight part of said metal compounds with respect to 100 weight part of the total of a polyimide precursor resin, a metal compound, and a viscosity modifier. It may be contained within the range.

  Moreover, in the formation method of the patterned conductor layer of this invention, the viscosity within the range of 10-100,000 cps may be sufficient as the viscosity of the said coating liquid.

  In the method for forming a patterned conductor layer of the present invention, the metal compound may be a metal salt or an organic carbonyl complex selected from Cu, Ni, Pd, Ag, Au, Pt, Sn, Fe, or Co. Good.

  In the method for forming a patterned conductor layer of the present invention, the viscosity modifier may be acetylacetone or ethyl acetoacetate.

  Moreover, in the formation method of the patterned conductor layer of this invention, the said insulation base material which has the said coating film is immersed in the solution of the boron compound of the density | concentration within the range of 0.005-0.5 mol / L in the said reduction | restoration process. May be. In this case, the boron compound may be sodium borohydride, potassium borohydride, or dimethylamine borane.

  Moreover, in the formation method of the patterned conductor layer of this invention, the said electroless-plating process uses the hypophosphorous acid type plating solution in the range of pH 4-7, or the dimethylaminoborane type plating solution in the range of pH 4-7. May be.

  Moreover, in the formation method of the patterned conductor layer of this invention, you may heat-process the said insulating base material which has the said coating film at the temperature within the range of 150-400 degreeC at the said imidation process.

  Further, in the method for forming a patterned conductor layer of the present invention, it may further include a surface treatment step of treating the surface of the insulating substrate with a silane coupling agent before the coating film forming step, or Prior to the coating film forming step, a surface treatment step of treating the surface of the insulating substrate with plasma may be further provided.

  Moreover, in the formation method of the patterned conductor layer of this invention, after the said electroless-plating process or the said imidation process, the electroplating which performs an electroplating by making the said electroless-plated layer into a nucleus and forms an electroplating layer A process may be provided.

The method for manufacturing the circuit board of the present invention includes:
A method of manufacturing a circuit board comprising an insulating substrate and a patterned conductor layer formed on the insulating substrate,
The patterned conductor layer is formed by any one of the above-described methods for forming a patterned conductor layer.

  The circuit board of the present invention is a circuit board manufactured by the method for manufacturing a circuit board.

  In the method for forming a patterned conductor layer of the present invention, a coating liquid is applied to an insulating substrate in a predetermined pattern using a dispenser to form a coating film, and then metal ions in the coating film are reduced to form metal particles. It was set as the structure which deposits. Therefore, the sintering process required in the conventional method using metal fine particles is unnecessary, and poor conduction is unlikely to occur. In addition, in the process of forming the patterned conductor layer, the coating liquid is directly applied to a predetermined pattern using a dispenser, so that the photolithography process and the etching process can be omitted.

  Further, by using a dispenser for applying the coating liquid, there is an effect that the patterned conductor layer can be easily formed even on a three-dimensional surface such as an uneven surface or a curved surface.

  In addition, the circuit board manufacturing method using the method for forming a patterned conductor layer according to the present invention can produce not only a flat plate but also a three-dimensional circuit board with a small number of steps.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a circuit board according to an embodiment of the present invention. FIG. 2 is an explanatory view showing, in an enlarged manner, a cross section of a main part of the circuit board of FIG.

  First, a circuit board 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The circuit board 1 includes an insulating base material 3 and a patterned conductor layer 5 serving as a wiring on the insulating base material 3. As the insulating base 3, for example, an inorganic substrate such as a glass substrate, a silicon substrate, or a ceramic substrate, or a synthetic resin substrate such as polyimide resin or polyethylene terephthalate (PET) can be used.

  As shown in FIG. 2, the patterned conductor layer 5 is formed so as to cover the electroless plating layer 9 formed on the polyimide resin layer 7 on the insulating substrate 3 and the electroless plating layer 9. And an electroplating layer 11. In the present embodiment, only the electroless plating layer 9 or the electroless plating layer 9 and the electroplating layer 11 are referred to as “patterned conductor layer 5”. The patterned conductor layer 5 may have an arbitrary layer interposed between the above layers.

  The polyimide resin layer 7 is mainly composed of a polyimide resin that is imidized by heating and dehydrating and cyclizing a polyamic acid that is a polyimide precursor resin. The polyimide resin is preferable because it has properties excellent in heat resistance and dimensional stability as compared with other synthetic resins such as thermosetting resins such as epoxy resins, phenol resins, and acrylic resins. The polyimide resin layer 7 of the present embodiment is formed by imidizing a polyimide precursor after pattern formation, and has high adhesion with the insulating substrate 3. Such a polyimide resin layer 7 is interposed between the insulating substrate 3 and the electroless plating layer 9 and serves as a binder.

  The electroless plating layer 9 is a metal film, and the type of metal is not limited, but using a metal type different from the metal constituting the electroplating layer 11 provides high adhesion to the electroplating layer 11. This is preferable. As the metal constituting the electroless plating layer 9, for example, Ni, Cu, Cr, Au, Pd, Sn, Rh, Ru and the like are preferable, and among these, Ni, Cu, Cr, Pd and the like are particularly preferable.

  The electroplating layer 11 is a metal film mainly composed of, for example, Cu, Au, Ni, Sn, Pd, Sn—Cu, or the like. Among these metals, Cu, Au and the like are particularly preferable.

[First Embodiment]
Next, a method for forming a patterned conductor layer according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a flowchart showing an outline of main steps in the method for forming a patterned conductor layer according to the present embodiment. 4 to 9 are explanatory views for explaining main processes of the patterned conductor layer forming method according to the present embodiment.

  As shown in FIG. 3, the patterned conductor layer forming method of the present embodiment includes steps S1 to S5 as main steps.

  In step S1, a coating liquid 20 containing a polyimide precursor resin, a metal compound, and a viscosity modifier is applied to the insulating substrate 3 in a predetermined pattern using a dispenser 30 as shown in FIG. To form a coating film (coating film forming step). FIG. 5 shows a cross-sectional shape of the coating film 40 applied on the insulating substrate 3 in the coating film forming step of Step S1.

  As the polyimide precursor resin used in the coating solution 20, a polyamic acid obtained from a component with the same monomer as the polyimide resin or a polyamic acid containing a photosensitive group such as an ethylenically unsaturated hydrocarbon group in the molecule is used. It is done. Such a polyimide precursor resin can be produced by reacting a known diamine compound and an acid anhydride in the presence of a solvent.

  Here, examples of the diamine compound used for the production of the polyimide precursor resin include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-amino). Phenoxy) 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.

  Examples of diamine compounds other than the above 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 -A Nophenoxy)] benzanilide, bis [4,4 '-(3-aminophenoxy)] benzanilide, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3 -Aminophenoxy) phenyl] fluorene, 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4'-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'-Diaminodiphenylsulfur 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-ter Phenyl, 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-me Ru-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 can also be used.

Examples of the acid anhydride used in the production of the polyimide precursor resin include pyromellitic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′- Examples thereof include diphenyl sulfone tetracarboxylic dianhydride and 4,4′-oxydiphthalic anhydride.
Further, as acid anhydrides other than the above, for example, 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 tetra Preferred examples include carboxylic dianhydride and bis (2,3-dicarboxyphenyl) ether dianhydride. Also 3,3``, 4,4 ''-, 2,3,3``, 4 ''-or 2,2 '', 3,3 ''-p-terphenyltetracarboxylic dianhydride 2,2-bis (2,3- or 3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3- or 3.4-dicarboxyphenyl) methane dianhydride, bis (2,3- Or 3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3- or 3,4-dicarboxyphenyl) ethane dianhydride, 1,2,7,8-, 1,2 , 6,7- or 1,2,9,10-phenanthrene-tetracarboxylic dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 2,2-bis (3,4-di Carboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6 -Tet Carboxylic dianhydride, 2,6- or 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8 -) Tetrachloronaphthalene-1,4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8,9-, 3,4,9,10-, 4,5,10,11- or 5,6,11,12-perylene-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic 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 can also be used.

  Each of the diamine compound and acid anhydride may be used alone or in combination of two or more. In addition, a diamine compound or acid anhydride other than the above can be used in combination with the diamine compound and acid anhydride. In this case, the proportion of the diamine compound or acid anhydride other than the above can be 90 mol% or less, preferably 50 mol% or less. In the production of the polyimide precursor resin, by selecting the diamine compound and the type of acid anhydride and the respective molar ratios when using two or more diamine compounds or acid anhydrides, thermal expansion, adhesiveness, The glass transition point (Tg) and the like can be controlled.

  The reaction between the diamine compound and the acid anhydride is preferably performed in an organic solvent. Although it does not specifically limit as such an organic solvent, Specifically, for example, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, Examples thereof include phenol, cresol, and γ-butyrolactone, and these can be used alone or in combination. The amount of the organic solvent used is not particularly limited, but the concentration of the polyimide precursor resin (polyamic acid) solution obtained by the polymerization reaction is in the range of about 5 to 30% by weight. It is preferable to adjust and use as described above. The solution adjusted in this way can be used as the coating solution 20 by adding a metal compound and a viscosity modifier.

  The polyimide precursor resin is preferably selected so as to include a thermoplastic polyimide resin after imidization. By using a thermoplastic polyimide resin, the polyimide resin layer 7 can be made to function as an adhesive layer that enhances the adhesion between the insulating substrate 3 and the electroless plating layer 9 after imidization.

  In the present embodiment, a polyamic acid varnish containing a polyamic acid can be used as the polyimide precursor resin solution. As the polyamic acid varnish, for example, thermoplastic polyimide varnish SPI-200N (trade name), SPI-300N (trade name), SPI-1000G (trade name) manufactured by Nippon Steel Chemical Co., Ltd., manufactured by Toray Industries, Inc. Trenice # 3000 (trade name) can be used.

The metal compound used for the coating solution 20 can be used without particular limitation as long as it is a compound containing a metal species having a redox potential higher than the redox potential of the reducing agent. Examples of the metal compound include those containing metal species such as Cu, Ni, Pd, Ag, Au, Pt, Sn, Fe, and Co. 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. 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.

  Examples of the organic carbonyl compound that forms 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.

  A metal compound is mix | blended so that it may become in the range of 5-60 weight part with respect to the total weight part 100 of a polyimide precursor resin, a metal compound, and a viscosity modifier, Preferably it exists in the range of 10-40 weight part. . In this case, if the metal compound is less than 5 parts by weight, the deposition of metal particles on the resin surface due to the reduction treatment is reduced, resulting in uneven thickness of the electroless plating layer. It is because the metal salt which cannot be melt | dissolved will precipitate.

  The viscosity modifier used for the coating liquid 20 is blended for the purpose of adjusting the viscosity of the coating liquid 20. By the addition of the viscosity modifier, the metal ion in the coating liquid 20 forms a chelate complex with the viscosity modifier and the metal ion instead of forming a chelate complex with the polyimide precursor resin. Thus, a viscosity modifier has the effect | action which suppresses the viscosity raise or gelatinization of the coating liquid 20 by chelate complex formation of a polyimide precursor resin and a metal ion.

  As the viscosity modifier, it is preferable to select a low-molecular organic compound that is highly reactive with metal ions (that is, capable of forming a metal complex). The molecular weight of the low molecular weight organic compound is preferably in the range of 50 to 300. Specific examples of such a viscosity modifier include acetylacetone and ethyl acetoacetate. Moreover, it is preferable to add the addition amount of a viscosity modifier in the range of 1-50 mol with respect to 1 mol of chelate complex compounds which can be formed, Preferably it is in the range of 2-20 mol.

  The viscosity of the coating solution 20 is preferably in the range of 10 to 100,000 cps. If the viscosity of the coating solution 20 is less than 10 cps, it may be difficult to control the target line width. If the viscosity of the coating liquid 20 exceeds 100,000 cps, the nozzle may be clogged with the coating liquid 20 and may not be applied to the insulating substrate 3. Further, the viscosity of the coating solution 20 can be adjusted by the line width of the coating film 40. For example, when the line width L of the coating film 40 is in the range of 10 to 100 μm, the viscosity of the coating solution 20 is preferably in the range of 10 to 100 cps. When the line width L of the coating film 40 is in the range of 100 to 200 μm, the viscosity of the coating solution 20 is preferably in the range of 100 to 500 cps. When the line width L of the coating film 40 is in the range of 200 to 300 μm, the viscosity of the coating solution 20 is preferably in the range of 500 to 50,000 cps. When the line width L of the coating film 40 is in the range of 300 to 400 μm, the viscosity of the coating solution 20 is preferably in the range of 50,000 to 70,000 cps. When the line width L of the coating film 40 is in the range of 400 to 500 μm, the viscosity of the coating solution 20 is preferably in the range of 70,000 to 90,000 cps. When the line width L of the coating film 40 is in the range of 500 to 600 μm, the viscosity of the coating solution 20 is preferably in the range of 90,000 to 100,000 cps.

  The coating solution 20 may contain a polyimide precursor resin in a concentration range of 5 to 20% by weight, a metal compound in an amount of 0.1 to 20% by weight, and a viscosity modifier in a concentration range of 1 to 40% by weight. preferable.

  As an optional component other than the essential components, for example, a leveling agent, an antifoaming agent, an adhesion-imparting agent, a crosslinking agent, and the like can be blended in the coating liquid 20.

  The coating liquid 20 can be prepared by, for example, mixing a polyimide precursor resin, a metal compound, a viscosity modifier, and the above-described optional components in an arbitrary solvent such as a pyridine solvent or an imidazole solvent. In addition, the coating liquid 20 can also be prepared by adding and mixing a metal compound and a viscosity modifier to the polyimide precursor resin solution (polyamic acid varnish) prepared in advance.

  In the coating film forming step of step S1, a dispenser 30 that discharges the coating liquid 20 can be of a known configuration. As a commercial product, for example, CASTPRO II (trade name; manufactured by Sony Corporation) can be used. By using the dispenser 30, it is possible to apply the coating liquid 20 directly in a predetermined pattern even on a three-dimensional surface such as an uneven surface or a curved surface. Therefore, not only the conventional two-dimensional (planar) circuit formation but also a three-dimensional (solid) circuit formation is possible.

  When the coating film 40 is formed, the line width L of the patterned coating film 40 is preferably in the range of 10 to 400 μm, and more preferably in the range of 15 to 200 μm. The line width L can be adjusted by selecting the diameter of the discharge nozzle 30a of the dispenser 30. In the present embodiment, as described above, the viscosity of the coating liquid 20 is in the range of 10 to 100,000 cps, so that the discharge nozzle 30a of the dispenser 30 is prevented from being clogged and fine with a desired line width. Various patterns can be formed.

  In the coating film forming step of step S1, after the coating liquid 20 is discharged onto the insulating base 3, the coating film 40 is formed by drying. The drying is preferably performed at a temperature in the range of 50 to 150 ° C., more preferably 80 to 140 ° C., and even more preferably 100 to 120 ° C. for about 3 to 10 minutes. This can be done by heating for a period of time. In this case, when the heating temperature exceeds 150 ° C., imidization of the polyimide precursor resin proceeds, and precipitation of particulate metal in the subsequent reduction step becomes difficult. Therefore, drying at a temperature within the above range is preferable. .

  Next, in step S2, the insulating base material 3 having the coating film 40 is immersed in a solution containing a reducing agent (reducing agent solution) (reducing step). Thereby, the metal ion in the coating film 40 is reduced by the action of the reducing agent, and the metal is deposited in the form of particles. FIG. 6 shows the state of the coating film 40a after the reduction step, and the particulate metal 41 is deposited on the coating film 40a (preferably the surface of the coating film 40a). In this step, the reducing agent can be sufficiently permeated into the coating film 40 by immersing the insulating base material 3 having the coating film 40 in the reducing agent solution. As a result, it is possible to suppress uneven deposition of the particulate metal in the reduction process.

  As the reducing agent used in the reduction step of Step S2, 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 in the coating film 40 may be insufficient. When the concentration exceeds 0.1 mol / L, the boron compound is applied by the action of the boron compound. The polyimide precursor resin in the film 40 may be dissolved.

  Further, as the treatment conditions of the reduction process, the insulating base material 3 on which the coating film 40 is formed is placed in a reducing agent solution at a temperature in the range of 10 to 90 ° C., preferably 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.

  Next, in step S3, electroless plating is performed on the coating film 40a after the reduction process in step S2 (electroless plating process). Electroless plating is performed by immersing the insulating base material 3 having the coating film 40a on which the particulate metal 41 is deposited in an electroless plating solution. By this electroless plating, as shown in FIG. 7, an electroless plating layer 9 covering the coating film 40a is formed. This electroless plating layer 9 becomes a nucleus of electroplating performed later.

  As an electroless plating solution used in the electroless plating step of Step S3, in consideration of the influence on the polyimide precursor resin, a neutral to weakly acidic hypophosphite-based nickel plating solution or a boron-based nickel plating solution Is preferably selected. As a commercial 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 4 to 7 neutral to weakly acidic. 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 processing temperature of the electroless plating step in step S3 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 20 second-10 minutes, Preferably it is 30 second-5 minutes, More preferably, it is 1 minute-3 minutes.

  Next, in step S4, the insulating base material 3 having the coating film 40a is heat-treated to imidize the polyimide precursor resin in the coating film 40a (imidization process). The polyamic acid in the coating film 40a is dehydrated, cyclized and imidized by heat treatment, whereby the polyimide resin layer 7 having excellent adhesion to the insulating substrate 3 is formed as shown in FIG. The imidization can be preferably performed in an inert gas atmosphere such as nitrogen using a heat treatment apparatus capable of heating the coating film 40a to a required temperature. The heat treatment can be performed for 1 to 60 minutes under a temperature condition within a range of 150 to 400 ° C., for example. If the heat treatment temperature is less than 150 ° C., imidization does not proceed sufficiently, and if the heat treatment temperature exceeds 400 ° C., there is a possibility of causing thermal decomposition of the polyimide resin.

Next, in step S5, electroplating is performed using the electroless plating layer 9 as a nucleus to form the electroplating layer 11 (electroplating step). As shown in FIG. 9, an electroplating layer 11 is formed by electroplating so as to cover the electroless plating layer 9. In addition, the electroplating process of this step S5 is an arbitrary process. The electroplating is performed by electroless plating of the insulating substrate 3 in a plating solution having a composition containing, for example, sulfuric acid, copper sulfate, hydrochloric acid, and a brightener [for example, McCulspec (trade name) manufactured by Nippon McDermitt as a commercial product]. The layer 9 is used as a cathode and a metal such as Cu is used as an anode. Current density in electroplating, for example, is preferably in the range of 1~3.5A / 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 board 1 in which the patterned conductor layer 5 serving as the metal wiring is formed on the surface of the insulating base 3 can be manufactured. The circuit board 1 can be suitably used for applications such as a hard printed board, a flexible printed board, a TAB (Tape Automated Bonding) material, a CSP (Chip Size Package) material, and a COG (Chip on Glass) material.

As described above, in the present embodiment, the coating liquid 20 is applied to the insulating substrate 3 in a predetermined pattern using the dispenser 30, and then metal ions in the coating film 40 are reduced to deposit the particulate metal 41. It was set as the structure made to do. Therefore, there is no need for the sintering step required in the prior art method using metal fine particles, and there is an effect that poor conduction is unlikely to occur. In addition, by directly applying the coating liquid 20 in a predetermined pattern using the dispenser 30, there is an effect that the photolithography process and the etching process can be omitted in the process of forming the patterned conductor layer 5.
In addition, by using the dispenser 30 for applying the coating liquid 20, for example, the patterned conductor layer 5 can be easily formed even on a three-dimensional surface such as an uneven surface or a curved surface of the insulating substrate 3. Play.

  In addition, the circuit board manufacturing method using the patterned conductor layer forming method of the present embodiment can produce not only a flat plate but also a three-dimensional circuit board 1 with a small number of steps.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a flowchart showing an outline of the procedure of the method for forming the patterned conductor layer according to the present embodiment. The method for forming a patterned conductor layer according to the present embodiment includes steps S11 to S16 shown in FIG. In the present embodiment, the surface treatment process in step S11 for modifying the surface of the insulating substrate 3 before the coating film forming process in step S12 corresponding to the coating film forming process in step S1 in the first embodiment. It has. In addition, since the process from step S12 to step S16 in this embodiment is the same as each process from step S1 to step S5 in the first embodiment, description thereof is omitted.

In the present embodiment, in the surface treatment process of step S11, it is preferable to select the content of the surface modification according to the material of the insulating base material 3. When the insulating base material 3 is comprised with inorganic materials, such as a glass substrate and a ceramic substrate, it is preferable to surface-treat the surface of the insulating base material 3 with a silane coupling agent. By the surface treatment with the silane coupling agent, the surface of the insulating base material 3 made of an inorganic material is hydrophobized, the flow of the liquid after the coating liquid 20 is applied can be suppressed, and the spread of the line width can be suppressed. Moreover, the adhesiveness of the coating film 40 and the insulating base material 3 can also be improved. Therefore, the accuracy of the pattern formed by the coating film 40 can be maintained, and the occurrence of defects in which the patterned conductor layer 5 is peeled off from the insulating base 3 can be reduced. In this case, the surface treatment is preferably performed so that the contact angle with water is within a range of 20 to 110 °, for example, and more preferably within a range of 30 to 100 °. In this case, if the contact angle with water is less than 20 °, it becomes difficult to suppress the flow of the liquid after the coating liquid 20 is applied, and if it exceeds 110 °, the coating film 40 and the insulating substrate 3 are in close contact with each other. May be reduced.
Examples of the silane coupling agent include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxy. Silane, 3- (2-aminoethyl) aminopropylmethyldiethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxy Silane, 3-mercaptopropyl Limethoxysilane, 3-isocyanatopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- Glycidoxytriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, And 3-acryloxypropyltriethoxysilane.

  Moreover, when the insulating base material 3 is comprised with synthetic resin materials, such as a polyimide substrate and a PET board | substrate, it is preferable to surface-treat the surface of the insulating base material 3 with plasma. By this surface treatment with plasma, the surface of the insulating substrate 3 can be roughened or the chemical structure of the surface can be changed. Thereby, the wettability of the surface of the insulating substrate 3 is improved, the affinity with the coating liquid 20 is increased, and the coating liquid 20 can be stably held in a predetermined shape on the surface. Therefore, the accuracy of the pattern formed by the coating film 40 can be maintained.

  As the plasma, for example, an atmospheric pressure type plasma processing apparatus is used, and plasma of argon, helium, nitrogen, or a mixed gas thereof is generated in a vacuum processing chamber. In this case, it is preferable that the processing pressure is in the range of 5000 to 200000 Pa, the processing temperature is in the range of 10 to 40 ° C., and the high frequency (or microwave) output is in the range of 50 to 400 W. In addition, when the material of the insulating base material 3 is a polyimide resin, the hydrolysis of the polyimide by an alkali treatment is effective because the adhesion between the coating film 40 and the insulating base material 3 can be improved. Here, examples of the alkali include alkali metal hydroxides such as LiOH, KOH, and NaOH, and preferably one or more selected from KOH or NaOH can be used.

As described above, by performing the surface treatment process of step S11, the flow of the liquid after the coating liquid 20 is applied can be suppressed, and the spread of the line width can be suppressed. Moreover, the adhesiveness of the coating film 40 and the insulating base material 3 can also be improved by surface treatment. Therefore, the accuracy of the pattern formed by the coating film 40 can be maintained, and the occurrence of defects in which the patterned conductor layer 5 is peeled off from the insulating base 3 can be reduced.
Other operations and effects of the present embodiment are the same as those of the first embodiment.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart showing an outline of the procedure of the method for forming the patterned conductor layer according to the present embodiment. The method for forming a patterned conductor layer according to the present embodiment includes steps S21 to S26 shown in FIG. In the first embodiment (FIG. 3), after depositing the particulate metal 41 on the coating film 40 in the reduction process in step S2, the electroless plating process in step S3 was performed. In the present embodiment, After the reduction process is repeatedly performed, an electroless plating process is performed. In addition, since the coating film formation process of step S21 in this Embodiment is the same as the coating film formation process of step S1 of 1st Embodiment, description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 11, after step S <b> 21 of forming the coating film, as step S <b> 22, the insulating base material 3 having the coating film 40 is placed in a solution containing a reducing agent (reducing agent solution). Immerse in (first reduction step). Thereby, the metal ions in the coating film 40 are reduced by the action of the reducing agent, and the particulate metal 41 is deposited. The conditions such as the type of reducing agent used in the reduction process in step S22, the concentration of the reducing agent, the processing time, and the temperature are the same as those in the reduction process in step S2 of the first embodiment, and thus description thereof is omitted.

  Next, in step S23, after the first reduction step of step S22, the insulating base material 3 having the coating film 40a on which the particulate metal 41 is deposited is changed into a solution containing a metal compound (hereinafter referred to as “metal compound solution”). Dipping) (dipping process). The metal compound used in the dipping process of step S23 can be used without particular limitation as long as it is a compound containing a metal species having a redox potential higher than the redox potential of the reducing agent. Examples of the metal contained in the metal compound include metals such as Cu, Ni, Pd, Ag, Au, Pt, Sn, Fe, and Co. As the metal compound containing these metals, the same metal salt or organic carbonyl complex as the coating solution used in step S21 can be used. The metal compound and the metal species contained in the metal compound solution may be the same as or different from the metal species and metal compound contained in the coating solution.

  In the metal compound solution used in the dipping step of step S23, the metal compound is preferably contained within a range of 30 to 300 mM (millimol / L; the same shall apply hereinafter), and contained within a range of 50 to 100 mM. More preferably. If the concentration of the metal compound is less than 30 mM, it is not preferable because it takes too much time to impregnate the coating film 40a with metal ions, and if it exceeds 300 mM, the surface of the polyimide precursor resin constituting the coating film 40a is corroded (dissolved). Cause deterioration.

  In addition to the metal compound, the metal compound solution may contain components such as a pH adjusting solution such as a buffer solution.

  In the dipping step, for example, the metal compound solution having the above concentration is adjusted to a temperature within the range of 20 to 40 ° C., and the insulating base material 3 is immersed therein for about 5 minutes to 5 hours.

  Next, in step S24, the insulating base material 3 having the coating film 40 is immersed again in a solution containing a reducing agent (reducing agent solution) (second reducing step). By this second reduction step, the metal ions in the coating film 40 are reduced by the action of the reducing agent, and more particulate metal 41 is deposited. In this way, the particulate metal 41 is densely formed so as to cover the coating film 40a, whereby a metal deposition layer (not shown) is formed. This metal deposition layer becomes the nucleus of the plating process performed later. Conditions such as the type of reducing agent used in the second reduction step, the concentration of the reducing agent, the treatment time, and the temperature are the same as those in the first reduction step in step S22.

  In the method for forming the patterned conductor layer of the present embodiment, the dipping process in step S23 and the second reduction process in step S24 are performed a plurality of times, for example, about 2 to 10 times, preferably 2 to 5 times as necessary. Can be repeated to some extent. Thereby, the metal deposit layer comprised from the particulate metal 41 becomes denser, and sufficient conduction can be ensured in the subsequent plating step.

  Next, in step S25, electroless plating is performed on the metal deposition layer (not shown) obtained in step S24 to form an electroless plating layer that covers the metal deposition layer (electroless plating step). Since the conditions such as the type of plating solution used in the electroless plating process, the processing time, and the temperature are the same as those in the electroless plating process of step S3 in the first embodiment, the description thereof is omitted. In the present embodiment, electroless plating is performed by immersing the insulating base material 3 on which the metal deposition layer is formed in a neutral electroless plating solution having a pH of about 7 for about 1 to 3 hours, for example. It is preferable. Thus, by immersing in a neutral electroless plating solution for a long time, the thickness equal to that of the electroplating layer is obtained without damaging the polyimide precursor resin constituting the coating film 40a on the insulating substrate 3. An electroless plating layer can be formed. Therefore, the electroplating step can be omitted also in this embodiment.

  Next, in step S26, the insulating base material 3 having the coating film 40a is heat-treated to imidize the polyimide precursor resin in the coating film 40a (imidization process). Since the conditions for this imidization step are the same as those in step S4 in the first embodiment, description thereof is omitted.

  As described above, in the method for forming the patterned conductor layer according to the present embodiment, the coating liquid containing the polyimide precursor resin, the metal compound, and the viscosity modifier is applied to the surface of the insulating substrate 3 by the dispenser 30 and dried. A coating film forming step for forming the coating film 40, a first reduction step for depositing the particulate metal 41 on the coating film 40 by immersing the insulating base material 3 having the coating film 40 in a reducing agent solution, A dipping process in which the insulating base material 3 having the coating film 40a on which the metal-like metal 41 is deposited is immersed in a metal compound solution, and after the dipping process, the insulating base material 3 having the coating film 40a is dipped again in the reducing agent solution, A second reduction step of depositing particulate metal 41 on 40a to form a metal deposition layer; and a step of performing neutral electroless plating on insulating substrate 3 having a metal deposition layer to form an electroless plating layer; , Heat treatment And a, and imidization to form a polyimide resin layer 7 a polyimide precursor resin and imidized in the film 40a. As a result, the patterned conductor layer 5 can be formed without the need for an electroplating step.

In the present embodiment, an electroplating step may be provided to form an electroplating layer before the imidization step in step S26 (after the electroless plating step) or after the imidization step. Moreover, it is also possible to implement an electroplating process instead of the electroless plating process of step S25. In this case, the conditions of the electroplating process are the same as step S5 in the first embodiment. Furthermore, as in the second embodiment, a surface treatment process for modifying the surface of the insulating base 3 can be provided before the coating film forming process.
Other operations and effects of the present embodiment are the same as those of the first embodiment.

  Next, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples.

[Reference example]
Preparation of polyimide precursor nickel complex solution:
200 ml of N-methyl-2-pyrrolidinone (hereinafter abbreviated as “NMP”), 7.36 g of 2,3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter abbreviated as “BPDA”) and 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter abbreviated as “BAPP”) was added and stirred for 4 hours at room temperature to prepare polyimide precursor varnish A.

  Next, a solution obtained by dissolving 5.85 g of commercially available nickel (II) acetylacetonate dihydrate in 50 ml of N-methyl-2-pyrrolidinone was added to the polyimide precursor varnish A. To this mixture, 30 g of acetylacetone was further added and stirred at room temperature for 1 hour to prepare a polyimide precursor nickel complex solution B. The viscosity of this solution was 820 cps as measured with an E-type viscometer.

[Example 1]
A 10 cm × 10 cm (0.7 mm thickness) test piece of alkali-free glass (Asahi Glass Co., Ltd. AN-100) was treated with a 5N aqueous sodium hydroxide 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”). Next, after removing the glass substrate of the test piece from the γ-APS aqueous solution, the glass substrate was dried and heated at 150 ° C. for 5 minutes. The polyimide precursor nickel complex solution B was drawn on this glass substrate using a dispenser (CASTPRO II manufactured by Sony Corporation) so as to be a straight line having a width of about 200 μm, and then dried at 130 ° C. for 30 minutes. The thickness of the coating film formed by drawing and drying was 2 μm.

  Next, the glass substrate was immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes. Next, after washing the glass substrate with ion-exchanged water, it was immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd .; Top Nicolon TOM-S (trade name)) at 80 ° C. for 30 seconds. A nickel layer was formed as a base for electrolytic copper plating.

Further, the nickel layer of the glass substrate was electroplated at a current density of 3.5 A / dm ^{2 in} an electro copper plating bath to form a copper wiring having a copper film thickness of 20 μm.

  The obtained copper wiring-formed glass substrate was heated to 300 ° C. in a nitrogen atmosphere and imidized at 300 ° C. for 5 minutes. Then, it cooled to normal temperature in nitrogen atmosphere, and obtained the copper wiring formation glass substrate.

[Example 2]
A test piece 10 cm × 10 cm (thickness 25 μm) of a polyimide film “Kapton EN” (trade name) manufactured by Toray DuPont was immersed in an aqueous 5N sodium hydroxide solution at 50 ° C. for 1 minute. Next, the polyimide substrate of the test piece was immersed in a 1% HCl aqueous solution at room temperature for 5 minutes, washed with pure water, and dried. The polyimide precursor nickel complex solution B was drawn on the polyimide substrate using a dispenser so as to be a straight line having a width of about 200 μm, and then dried at 130 ° C. for 30 minutes. The thickness of the film formed by drawing and drying was 2 μm.

  Next, the polyimide substrate was immersed in a 50 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes. Next, the polyimide substrate is washed with ion-exchanged water and then immersed in an electroless nickel plating bath “Top Nicolon TOM-S” (trade name; manufactured by Okuno Pharmaceutical Co., Ltd.) for 30 seconds at 80 ° C. A nickel layer was formed as a base for copper plating.

Furthermore, the nickel layer of the polyimide substrate was electroplated at a current density of 3.5 A / dm ^{2 in} an electrocopper plating bath to form a copper wiring having a copper film thickness of 20 μm.

  The obtained copper wiring-formed polyimide substrate was heated to 300 ° C. in a nitrogen atmosphere, imidized at 300 ° C. for 5 minutes, and then cooled to room temperature in a nitrogen atmosphere to obtain a copper wiring-forming polyimide substrate.

[Example 3]
A test piece 10 cm × 10 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% by weight γ-APS aqueous solution. The glass substrate of this test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. The polyimide precursor nickel complex solution B was drawn on a straight line having a width of about 200 μm on this glass substrate using a dispenser (manufactured by Sony Corporation; CASTPRO II), and then dried at 130 ° C. for 30 minutes. The thickness of the film formed by drawing and drying was 5 μm.

  Next, the glass substrate was immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes. Next, the glass substrate was washed with ion-exchanged water and then immersed in a 500 mM nickel acetate aqueous solution for 10 minutes. Next, the glass substrate was immersed in a 500 mM dimethylamine borane aqueous solution at 50 ° C. for 3 minutes, thereby forming a nickel layer serving as a base for neutral electroless copper plating. Furthermore, in order to activate the nickel layer surface, it processed using the palladium chloride type | system | group activator [Okuno Pharmaceutical Co., Ltd. make; ICP Axela (brand name)].

  Furthermore, after using a neutral electroless copper plating bath and setting the bath temperature to 50 ° C., the glass substrate having the nickel layer was immersed for 2 hours to form a wiring having a copper film thickness of 20 μm on the nickel layer. In addition, this neutral electroless copper plating bath is 3.36 g (0.025 mol) of copper (II) chloride (anhydrous), 3.09 g (0.05 mol) of boric acid, and 8.405 g (0.005 mol) of EDTA-2Na at room temperature. 0,245 mol), 2.945 g (0.05 mol) of dimethylamine borane was dissolved in 500 ml of distilled water, and 50% sodium hydroxide was added to a pH of 7.0.

  The obtained copper wiring formed glass substrate was heated to 300 ° C. in a nitrogen atmosphere, imidized at 300 ° C. for 5 minutes, and then cooled to room temperature in a nitrogen atmosphere to obtain a copper wiring forming glass substrate. It was.

  In addition, this invention is not limited to said each embodiment, A various change is possible. For example, in the first embodiment and the second embodiment, the imidization process is performed after the electroless plating process (before the electroplating process), but the imidization process is performed after the electroplating process. Can also be implemented.

  In the first embodiment and the second embodiment, it is also possible to provide a washing step (washing step) with pure water, ion-exchanged water or the like after the reduction step and after the electroless plating step. It is.

It is explanatory drawing which shows the structure of the circuit board based on the 1st Embodiment of this invention. It is sectional drawing which expands and shows the principal part of the circuit board shown in FIG. It is a flowchart which shows the outline | summary of the procedure of the formation method of the patterned conductor layer which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating the coating film formation process in the formation method of the patterned conductor layer which concerns on the 1st Embodiment of this invention. It is explanatory drawing for demonstrating the state of the coating film after a coating film formation process. It is explanatory drawing for demonstrating the state of the coating film after a reduction process. It is explanatory drawing for demonstrating the state of the electroless-plating layer after an electroless-plating process. It is explanatory drawing for demonstrating the state of the polyimide resin layer after an imidation process. It is explanatory drawing for demonstrating the state of the patterned conductor layer after an electroplating process. It is a flowchart which shows the outline | summary of the procedure of the formation method of the patterned conductor layer which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows the outline | summary of the procedure of the formation method of the patterned conductor layer which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit board, 3 ... Insulation base material, 5 ... Patterned conductor layer, 7 ... Polyimide resin layer, 9 ... Electroless plating layer, 11 ... Electroplating layer, 20 ... Coating liquid, 30 ... Dispenser, 40, 40a ... Coating film, 41 ... particulate metal.

Claims (15)

A coating film forming step in which a coating liquid containing a polyimide precursor resin, a metal compound, and a viscosity modifier is applied to the surface of the insulating substrate using a dispenser and dried to form a coating film having a predetermined pattern; ,
A reduction step of reducing a metal ion in the coating film by causing a reducing agent to act, and depositing particulate metal on the coating film;
An electroless plating step of forming an electroless plating layer to be a patterned conductor layer by performing electroless plating on the coating film on which the particulate metal is deposited;
An imidization step of performing a heat treatment to imidize the polyimide precursor resin in the coating film to form a polyimide resin layer;
A method for forming a patterned conductor layer, comprising:   The method for forming a patterned conductor layer according to claim 1, wherein a line width of the coating film having the predetermined pattern is in a range of 10 to 400 μm.   The said coating liquid contains the said metal compound in the range of 5-60 weight part with respect to 100 weight part of the sum total of a polyimide precursor resin, a metal compound, and a viscosity modifier. The method for forming a patterned conductor layer according to claim 2.   4. The method for forming a patterned conductor layer according to claim 1, wherein the coating solution has a viscosity within a range of 10 to 100,000 cps.   5. The metal compound according to claim 1, wherein the metal compound is a metal salt or an organic carbonyl complex selected from Cu, Ni, Pd, Ag, Au, Pt, Sn, Fe or Co. Method for forming a patterned conductor layer.   The method for forming a patterned conductor layer according to any one of claims 1 to 5, wherein the viscosity modifier is acetylacetone or ethyl acetoacetate.   The said reduction | restoration process WHEREIN: The said insulation base material which has the said coating film is immersed in the solution of the boron compound of the density | concentration within the range of 0.005-0.5 mol / L, The one of Claim 1 thru | or 6 characterized by the above-mentioned. The formation method of the patterned conductor layer as described in any one of.   The method for forming a patterned conductor layer according to claim 7, wherein the boron compound is sodium borohydride, potassium borohydride, or dimethylamine borane.   The electroless plating step uses a hypophosphite plating solution within a pH range of 4 to 7 or a dimethylaminoborane plating solution within a pH range of 4 to 7. The formation method of the patterned conductor layer of description.   The patterned conductor layer according to any one of claims 1 to 9, wherein, in the imidization step, the insulating base material having the coating film is heat-treated at a temperature in a range of 150 to 400 ° C. Forming method.   The patterned conductor layer according to claim 1, further comprising a surface treatment step of treating the surface of the insulating substrate with a silane coupling agent before the coating film forming step. Forming method.   The method for forming a patterned conductor layer according to any one of claims 1 to 10, further comprising a surface treatment step of treating the surface of the insulating substrate with plasma before the coating film forming step. .   13. An electroplating step of forming an electroplating layer by performing electroplating with the electroless plating layer as a nucleus after the electroless plating step or after the imidization step. The method for forming a patterned conductor layer according to any one of the above. A method of manufacturing a circuit board comprising an insulating substrate and a patterned conductor layer formed on the insulating substrate,
A method for manufacturing a circuit board, wherein the patterned conductor layer is formed by the method for forming a patterned conductor layer according to any one of claims 1 to 13.   A circuit board manufactured by the method for manufacturing a circuit board according to claim 14.

Images