JP2008294060A - Composition for forming conductor layer, forming method of conductor layer, and manufacturing method of circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming a conductor layer, which can be easily applied and handled by suppressing an increase in viscosity of the composition and is also applicable to a wet reduction method. <P>SOLUTION: The composition for forming a conductor layer is used as an application liquid for forming a conductor layer on an insulating base material. The composition contains a polyimide precursor resin, a metal compound and a nitrogen-containing heterocyclic compound as a viscosity adjusting agent. Tertiary amino compound such as pyridine and imidazole is used as the nitrogen-containing heterocyclic compound. An organic carbonyl compound can be contained as the viscosity adjusting agent together with the nitrogen-containing heterocyclic compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  With recent downsizing of electronic components and higher signal transmission speed, high-density wiring is required on circuit boards such as flexible printed boards. In order to realize high-density wiring, it is indispensable to finely process the patterned conductor layer. However, when the conductor layer is finely processed, there is a drawback that the adhesion to the substrate is lowered. Therefore, in order to improve the reliability and yield of electronic components, it has become important to improve the adhesion between the conductor layer and the base material so that it can withstand fine processing.

  As a method for forming a conductive layer having a fine pattern and excellent adhesion to a substrate on a circuit board, Patent Document 1 discloses a metal superfine particle having a fine average particle diameter in a thermosetting resin composition containing an organic solvent. A method using a conductive metal paste in which fine particles are uniformly dispersed is described. In the method of this patent document 1, after apply | coating a conductive metal paste to a board | substrate using an inkjet printing technique, a coating film is heated to the temperature of 150 to 210 degreeC. This heating is performed for the purpose of sintering the metal fine particles to make the coating film conductive and to cure the thermosetting resin. However, in the method of Patent Document 1, if the fine metal particles are not successfully sintered, the conduction of the patterned conductor layer cannot be achieved, and the reliability of the electronic component may be reduced.

  In addition, as a method for forming a patterned conductor layer without using metal fine particles, Patent Document 2 describes a method using a polyimide precursor resin solution containing a palladium ion-containing compound and a polyimide precursor resin. In the method of Patent Document 2, 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 reduce metal ions to form a plating base nucleus, and then a plating base metal layer is formed by electroless plating. Further, after the electroplating layer is formed on the plating base metal layer by electroplating or before the formation, the polyimide precursor resin is heated and imidized to form a polyimide resin layer. Since the technique described in Patent Document 2 does not use a conductive paste containing metal fine particles, there is an advantage that a patterned conductor layer can be formed regardless of the sintered state of the metal fine particles.

JP 2002-324966 A JP 2005-154880 A

  As in Patent Document 2, in a polyimide precursor resin solution containing palladium ions and a polyimide precursor resin, a three-dimensional cross-linking reaction occurs between molecules of palladium ions and a polyamic acid that is a polyimide precursor resin. Arise. For this reason, the polyimide precursor resin solution is thickened and gelled with the passage of time, and it becomes difficult to apply, store and handle the polyimide precursor resin solution. In order to prevent such thickening and gelation, in the technique of Patent Document 2, a low molecular organic carbonyl compound such as acetylacetone is blended in the polyimide precursor resin solution as a viscosity stabilizer. However, since low molecular organic carbonyl compounds such as acetylacetone have a dissolving action on the polyimide precursor resin, when the metal ion reduction treatment is performed by a wet reduction method, the polyimide precursor resin is low molecular organic carbonyl. There was a problem that the reduction efficiency was reduced by elution into the reducing agent solution by the action of the compound.

  The above problem becomes more prominent as the amount of the low-molecular-weight organic carbonyl compound increases relative to the amount of the palladium compound. In the technique of Patent Document 2, a low molecular weight organic carbonyl compound is added in a large amount of 60% by weight or more with respect to the compounding amount of the palladium compound in order to surely suppress the thickening and gelation of the polyimide precursor resin solution. There must be. Thus, in the method of Patent Document 2 using a large amount of a low molecular weight organic carbonyl compound as a viscosity stabilizer, a wet reduction method with good reduction efficiency cannot be adopted, and metal ions must be reduced by an ultraviolet irradiation method. There wasn't.

  The present invention has been made in view of such problems, and the object thereof is a composition for forming a conductor layer, which is easy to apply and handle because the increase in viscosity of the composition is suppressed, and which can also be applied to a wet reduction method. To provide things.

The composition for forming a conductor layer of the present invention is used as a coating solution for forming a conductor layer on an insulating substrate,
A polyimide precursor resin;
A metal compound;
A nitrogen-containing heterocyclic compound as a viscosity modifier;
It contains.

  In the present invention, the “conductor layer” may be a single metal deposition layer or a layer in which another layer is laminated on the metal deposition layer. For example, a laminate of a metal deposition layer formed on an insulating substrate, an electroless plating layer and / or an electroplating layer is also a “conductor layer”. Furthermore, the “conductor layer” may have any layer other than the metal deposition layer, the electroless plating layer, and the electroplating layer.

  In the conductor layer forming composition of the present invention, an organic carbonyl compound may be contained together with the nitrogen-containing heterocyclic compound as the viscosity modifier.

  In the composition for forming a conductor layer of the present invention, the nitrogen-containing heterocyclic compound may be a tertiary amino compound.

The method for forming a conductor layer of the present invention is a method for forming a conductor layer on an insulating substrate,
A coating film forming step of coating the conductive layer forming composition as a coating liquid on the surface of the insulating substrate and drying to form a coating film; and
A reduction step of reducing metal ions present in the coating film and forming a metal deposition layer as the conductor layer on the surface of the coating film;
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 has.

The circuit board manufacturing method of the present invention is a method comprising an insulating base material and a conductor layer formed on the insulating base material,
The conductor layer is formed by the method for forming a conductor layer.

  Since the composition for forming a conductor layer of the present invention contains a nitrogen-containing heterocyclic compound as a viscosity modifier, crosslinking formation between the metal ion and the polyimide precursor resin is suppressed, and no organic carbonyl compound is added. Can prevent the composition viscosity from increasing and gelation. Moreover, in the composition for forming a conductor layer of the present invention, even when a nitrogen-containing heterocyclic compound and an organic carbonyl compound are used in combination as a viscosity modifier, the compounding amount of the organic carbonyl compound can be greatly reduced as compared with the conventional technique. . From the above, the composition for forming a conductor layer of the present invention is excellent in storage stability and handleability, has an effect that it can be stored easily and can be applied by various application means. Is.

  In addition, the composition for forming a conductor layer of the present invention does not contain an organic carbonyl compound as a viscosity modifier, or the content thereof is extremely small. Therefore, a wet reduction method having excellent reduction efficiency when reducing metal ions is used. The solid content concentration in the composition can be easily finely adjusted.

  Moreover, the nitrogen-containing heterocyclic compound mix | blended with the composition for conductor layer formation of this invention has the effect | action which accelerates | stimulates the imidation reaction of a polyimide precursor resin. For this reason, when the polyimide precursor resin is imidized by heating after applying the composition for forming a conductor layer of the present invention to an insulating substrate, imidization proceeds in a short time and imidization is insufficient. Thus, a polyimide resin layer having high adhesion to the insulating substrate can be formed.

  In the method for forming a conductor layer of the present invention, since the composition for forming a conductor layer containing a nitrogen-containing heterocyclic compound as a viscosity modifier is used as a coating solution, it is easy to adjust the viscosity of the coating solution. For this reason, various application | coating means can be selected, for example, thin-line application | coating by a dispenser etc. is also possible. In addition, by using the composition for forming a conductor layer of the present invention that does not contain an organic carbonyl compound or the amount of which is suppressed as much as possible, a wet reduction method with excellent reduction efficiency is adopted as a method for reducing metal ions. You can also For this reason, it is possible to form a conductor layer with few defects by reduction treatment of metal ions, and there is an effect that the electroless plating step can be omitted.

  In addition, according to the method for manufacturing a circuit board using the method for forming a conductor layer of the present invention, it is possible to manufacture a highly reliable electronic component with excellent adhesion between the insulating base and the conductor layer at a high yield. Play.

Next, embodiments of the present invention will be described in detail.
The composition for forming a conductor layer according to this embodiment is used as a coating solution for forming a conductor layer on an insulating substrate. This composition for forming a conductor layer contains a polyimide precursor resin, a metal compound, and a viscosity modifier.

  In the present embodiment, the polyimide precursor resin used in the composition for forming a conductor layer includes a polyamic acid obtained from the same monomer component as the polyimide resin, or a photosensitive group in the molecule, such as an ethylenically unsaturated hydrocarbon. A polyamic acid containing group is used. 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, and 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)] benzopheno Bis [4- (3-aminophenoxy)] benzophenone, bis [4,4 ′-(4-aminophenoxy)] 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 4,4'-methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diaminodiphenylethane, 3, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone 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-phenylene Diamine, 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, it can also be used piperazine.

  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 diphenylsulfone tetracarboxylic dianhydride and 4,4′-oxydiphthalic anhydride. Moreover, as an acid anhydride 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 -Dicarboxyphenyl) tetrafluoropropane dianhydride, 2,3,5,6-cyclohexane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalene Tetracarboxylic 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-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, hexamethyl phosphoramide, 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 prepared as described above can be used as the conductor layer forming composition of the present embodiment 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 after imidization can be made to function as an adhesive layer for fixing, for example, an insulating base material and a conductor layer.

  The metal compound used for the conductor layer forming composition 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 used in the reduction step. Examples of the metal compound 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.

  The compounding amount of the metal compound is in the range of 5 to 60 parts by weight, preferably in the range of 10 to 40 parts by weight, with respect to 100 parts by weight of the total of the polyimide precursor resin, the metal compound and the viscosity modifier. To. In this case, if the metal compound is less than 5 parts by weight, the metal particles deposited on the surface of the polyimide precursor resin due to the reduction treatment are reduced, resulting in unevenness in the thickness of the conductor layer (for example, electroless plating layer). This is because the metal salt that cannot be dissolved in the liquid of the composition for forming a conductor layer is precipitated when the amount exceeds this part. In addition, when not performing electroless plating after a reduction process, it is preferable to set many compounding quantities of a metal compound compared with the case where electroless plating is performed. This point will be described later.

  In the composition for forming a conductor layer of the present embodiment, the viscosity modifier is blended for the purpose of adjusting the viscosity of the composition. The viscosity modifier suppresses an increase in viscosity or gelation of the composition for forming a conductor layer due to formation of a chelate complex between a polyimide precursor resin and a metal ion. That is, by adding a viscosity modifier, the viscosity modifier and the metal ion form a chelate complex instead of the metal ion in the composition forming a chelate complex with the polyimide precursor resin. As described above, in the composition for forming a conductor layer, the viscosity modifier blocks the three-dimensional cross-linking between the polyimide precursor resin and the metal ions, thereby suppressing thickening and gelation.

  As the viscosity modifier in the composition for forming a conductor layer of the present embodiment, a nitrogen-containing heterocyclic compound can be used. Moreover, in this Embodiment, organic carbonyl compounds, such as acetylacetone, can also be used with a nitrogen-containing heterocyclic compound as a viscosity modifier. By using a nitrogen-containing heterocyclic compound as a viscosity modifier, an organic carbonyl compound that has been conventionally used as a viscosity modifier is not used, or the amount used can be significantly suppressed.

  As the nitrogen-containing heterocyclic compound, a tertiary amino compound is preferable. Since the tertiary amino compound also has an action of promoting imidization of the polyimide precursor resin, the imidation of the polyimide precursor resin can be progressed reliably in a short time, and the adhesion to the insulating base material can be further improved. The effect that it can raise is also acquired. On the other hand, among the nitrogen-containing heterocyclic compounds, primary amino compounds and secondary amino compounds are not preferable because they may affect the imidization reaction of the polyimide precursor resin and change the imide structure. Moreover, even if it is a tertiary amino compound, for example, an aliphatic tertiary amino compound such as DBU (diazabicyclooundecene), DABCO (diazabicyclooctane), etc. is itself a polyimide precursor. Since it may react with body resin, it is not preferable.

  In the present embodiment, as the tertiary amino compound, for example, substituted or unsubstituted pyridine, bipyridine, imidazole, picoline, lutidine, pyrazole, triazole, benzimidazole, purine, imidazoline, pyrazoline, quinoline, isoquinoline, dipyridyl, Diquinolyl, pyridazine, pyrimidine, pyrazine, phthalazine, quinoxaline, quinazoline, cinnoline, naphthyridine, acridine, phenanthridine, benzoquinoline, benzoisoquinoline, benzocinnoline, benzophthalazine, benzoquinoxaline, benzoquinazoline, phenanthroline, phenazine, carboline, perimidine Use triazine, tetrazine, pteridine, oxazole, benzoxazole, isoxazole, benzisoxazole, etc. Rukoto can. These tertiary amino compounds can be used in combination of two or more.

  Among the tertiary amino compounds, at least one selected from substituted or unsubstituted pyridine, 2,2′-bipyridine, imidazole, 1-methylimidazole, 2-methylimidazole, 2-picoline and 2,6-lutidine. And preferably at least one compound selected from unsubstituted pyridine, 2,2′-bipyridine, imidazole, 1-methylimidazole, 2-methylimidazole, 2-picoline and 2,6-lutidine. Is more preferable.

  The compounding amount of the nitrogen-containing heterocyclic compound as the viscosity modifier is preferably 0.1 mol or more and 20 mol or less, and is set within a range of 0.5 to 2 mol, with respect to 1 mol of the chelate complex compound that can be formed. Is more preferable. Even if a nitrogen-containing heterocyclic compound is added in a large excess amount exceeding 20 moles per mole of the chelate complex compound, the effect is not expected to be increased so that a metal compound (for example, a metal acetylacetonate complex) is a polyimide precursor. This is undesirable because it causes problems such as insoluble in the body resin solution.

  Moreover, in order to make a nitrogen-containing heterocyclic compound act effectively as an imidation accelerator of a polyimide precursor resin, the compounding amount of the nitrogen-containing heterocyclic compound is 1 mol with respect to 1 mol of the chelate complex compound that can be formed. It is preferable to set. In this case, the viscosity can be adjusted by further adding an organic carbonyl compound such as acetylacetone.

  Also, in the composition for forming a conductor layer of the present embodiment, the combined use of a nitrogen-containing heterocyclic compound and an organic carbonyl compound as a viscosity modifier greatly increases the compounding amount of the organic carbonyl compound compared to the conventional technology. A sufficient viscosity adjusting effect can be obtained while reducing. Specifically, by using the nitrogen-containing heterocyclic compound in combination, the viscosity of the organic carbonyl compound such as acetylacetone can be sufficiently adjusted by adding a small amount of about 1/50 to 1/5 of the conventional number. As a result, fine adjustment of the solid content concentration of the conductive layer forming composition as the varnish can be easily performed.

  As the organic carbonyl compound that can be used in the present embodiment, it is preferable to select a low molecular weight compound that is highly reactive with a metal ion (that is, capable of forming a metal complex). The molecular weight of the organic carbonyl compound is preferably in the range of 50 to 300, for example. Specific examples of such organic carbonyl compounds include acetylacetone and ethyl acetoacetate.

  20 mol or less is preferable with respect to 1 mol of chelate complex compounds which can be formed, and, as for the compounding quantity of the organic carbonyl compound as a viscosity modifier, it is more preferable to set in the range of 1-10 mol. Even if the organic carbonyl compound is blended in an amount exceeding 20 moles with respect to 1 mole of the chelate complex compound, it is difficult to lower the viscosity of the original polyimide precursor resin solution.

  The composition for forming a conductor layer contains 5 to 20% by weight of a polyimide precursor resin, 0.1 to 20% by weight of a metal compound, and 1 to 40% by weight of a viscosity modifier. Is preferred.

  In the composition for forming a conductor layer of the present embodiment, for example, a leveling agent, an antifoaming agent, an adhesion-imparting agent, a crosslinking agent and the like can be blended as optional components other than the essential components.

  The composition for forming a conductor layer can be prepared, for example, by mixing a polyimide precursor resin, a metal compound, a viscosity modifier and the above optional components in an arbitrary solvent such as a pyridine solvent or an imidazole solvent. In addition, the composition for conductor layer formation 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 beforehand. Examples of the polyamic acid varnish that can be used as the mother liquor of the conductor layer forming composition include thermoplastic polyimide varnish SPI-200N (trade name), SPI-300N (trade name) manufactured by Nippon Steel Chemical Co., Ltd. SPI-1000G (trade name), Toray Nice # 3000 (trade name) manufactured by Toray Industries, Inc. can be exemplified.

  The viscosity of the composition for forming a conductor layer varies depending on the application method when applied to the insulating base material. For example, when applied to the base material using an applicator such as a dispenser, the viscosity ranges from 10 to 100,000 cps. It is preferable to adjust within. In this case, if the viscosity of the composition for forming a conductor layer is less than 10 cps, control of the intended line width may be difficult. Moreover, when the viscosity of the composition for forming a conductor layer exceeds 100,000 cps, the nozzle may be clogged with a coating solution (the composition for forming a conductor layer) and may not be applied to a substrate.

Next, a method for forming a conductor layer according to an embodiment of the present invention will be described in detail with reference to the drawings. The formation method of the conductor layer which concerns on the 1st-4th embodiment illustrated below has the characteristics in the point which forms a conductor layer on an insulating base material using the said composition for conductor layer formation. is there.
[First Embodiment]
FIG. 1 is a perspective view showing a schematic configuration of a circuit board to which the method for forming a conductor layer according to the first embodiment is applied. 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, the circuit board 1 will be described with reference to FIGS. The circuit board 1 includes an insulating base material 3 and a 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.

  The conductor layer 5 is a conductor layer patterned into a predetermined shape. As shown in FIG. 2, the conductor layer 5 includes a metal deposit layer 9 formed on the polyimide resin layer 7 on the insulating substrate 3, and an electroless plating layer formed so as to cover the metal deposit layer 9. 11 and, further, an electroplating layer 13 formed so as to cover the electroless plating layer 11. In the present embodiment, only the metal deposition layer 9, the metal deposition layer 9 and the electroless plating layer 11, or the metal deposition layer 9, the electroless plating layer 11, and the electroplating layer 13 are referred to as “conductor layers 5”, respectively. . In addition, the conductor layer 5 may have arbitrary layers other than each said layer.

  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 preferably used 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 resin after pattern formation, and has high adhesion with the insulating substrate 3. Such a polyimide resin layer 7 is interposed between the insulating base material 3 and the metal deposit layer 9 and serves as a binder.

  The metal deposition layer 9 is a metal film made of metal deposited on the surface of the polyimide precursor resin (polyimide resin layer 7) by reducing metal ions derived from the metal compound contained in the conductor layer forming composition. The kind of the metal in the metal deposit layer 9 is the same as the metal contained in the conductor layer forming composition.

  The electroless plating layer 11 is a metal film formed by electroless plating, and the type of metal is not limited, but it is possible to use a metal type different from the metal constituting the electroplating layer 13 with the electroplating layer 13. It is preferable because high adhesion can be obtained. As the metal constituting the electroless plating layer 11, 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 13 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.

  Next, a method for forming a 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 conductor layer according to the present embodiment. 4 to 9 are explanatory views for explaining main steps of the method for forming a conductor layer according to the present embodiment.

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

  In step S1, a coating solution 20 as a conductor layer forming composition containing a polyimide precursor resin, a metal compound, and a viscosity modifier is applied to the insulating substrate 3 using a dispenser 30 as shown in FIG. It is applied in a predetermined pattern and dried to form a coating film 40 (coating film forming step). In addition, the code | symbol 40a in FIG. 4 is a coating film before drying. 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.

  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.

  The line width L of the patterned coating film 40 formed using the dispenser 30 is adjusted for the viscosity of the coating liquid 20 as the conductor layer forming composition, the nozzle (discharge port) diameter control, and the discharge pressure. It can be adjusted to a desired size by controlling the drawing, controlling the drawing speed, or a combination thereof. In the present embodiment, by setting the viscosity of the coating liquid 20 within the range of 10 to 100,000 cps, a fine pattern is formed with a desired line width while preventing the discharge nozzle 30a of the dispenser 30 from being clogged. be able to. Further, the viscosity of the coating liquid 20 can be set according to the line width L of the pattern of the applied coating film 40. For example, when the line width L of the pattern 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.

  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 metal deposition becomes difficult in the subsequent reduction step. Therefore, drying at a temperature within the above range is preferable.

  Next, in step S2, metal ions in the coating film 40 are reduced to form the metal deposition layer 9 (reduction process). The reduction treatment method in the reduction process of step S2 is not particularly limited. For example, a wet reduction method, a hydrogen reduction method, an ultraviolet irradiation reduction method, an electron beam irradiation method, a heating reduction method, an electrical reduction method, or the like is adopted. can do. The wet reduction method is a method for reducing metal ions by immersing the coating film 40 in a solution containing a reducing agent (reducing agent solution). The hydrogen reduction method is a method in which the coating film 40 is placed in a hydrogen atmosphere and metal ions are reduced. The ultraviolet irradiation reduction method is a method of reducing metal ions by irradiating the coating film 40 with ultraviolet rays. Among these reduction treatment techniques, it is preferable to employ a wet reduction method that has little unevenness of precipitation of the metal deposition layer 9 in the reduction process and has a large effect of forming a uniform metal film in a short time.

  In the case where a large amount of organic carbonyl compounds such as acetylacetone and ethyl acetoacetate are blended as a viscosity modifier of the coating solution 20 as in the above-mentioned Patent Document 2 (Japanese Patent Laid-Open No. 2005-154880), these organic carbonyls are used. Since the compound has a dissolving action with respect to the polyimide precursor resin, there is a problem that the polyimide precursor resin is eluted in the reducing agent solution in the wet reduction step and the reduction efficiency is lowered. For this reason, in the method of patent document 2 using the coating liquid which mix | blended the organic carbonyl compound, the wet reduction method with sufficient reduction efficiency was not employable. On the other hand, in the method for forming a conductor layer according to the present embodiment, since the coating liquid 20 (conductor layer forming layer composition) does not contain a metal compound, a wet reduction method with good reduction efficiency can be adopted. Is possible.

  As a reducing agent used in the wet reduction method which is the most preferable reduction treatment method, 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 coating film 40 may be insufficient. When the concentration exceeds 0.1 mol / L, the action of the boron compound may occur. The polyimide precursor resin in the coating film 40 may be dissolved.

  In the wet reduction treatment, 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 in the range of 50 to 70 ° C, for 20 seconds to 30 seconds. Immerse in minutes, preferably 30 seconds to 10 minutes, more preferably 1 minute to 5 minutes.

  In the wet reduction method, 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, metal deposition unevenness can be suppressed. Through the above reduction process, the metal ions on the surface of the coating film 40 are reduced and the metal is deposited, so that the metal deposition layer 9 covering the coating film 40 is formed as shown in FIG. This metal deposition layer 9 can be used as a nucleus of electroless plating performed later.

  Next, in step S3, electroless plating is performed on the metal deposition layer 9 formed in the reduction process of step S2 (electroless plating process). Electroless plating is performed by immersing the insulating base material 3 having the coating film 40 on which the metal deposition layer 9 is formed in an electroless plating solution. By this electroless plating, as shown in FIG. 7, an electroless plating layer 11 covering the metal deposit layer 9 is formed. This electroless plating layer 11 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 time 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 40 is heat-treated to imidize the polyimide precursor resin in the coating film 40 (imidization process). By dehydrating and cyclizing and imidizing the polyamic acid in the coating film 40 by heat treatment, a 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 40 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 11 as a nucleus to form the electroplating layer 13 (electroplating step). As shown in FIG. 9, an electroplating layer 13 is formed by electroplating so as to cover the electroless plating layer 11. In addition, the electroplating process of this step S5 is an arbitrary process. Electroplating is, for example, electroless on the insulating base material 3 in a plating solution having a composition containing sulfuric acid, copper sulfate, hydrochloric acid, and a brightener [for example, McCuspec (trade name) manufactured by Nippon McDermitt as a commercial product]. The plating layer 11 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 conductor layer 5 to be a 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.

  In the method for forming a conductor layer according to the present embodiment, the composition for forming a conductor layer containing a nitrogen-containing heterocyclic compound as a viscosity modifier is used as the coating liquid 20. Fine wire coating can be employed. Furthermore, it is possible to employ a wet reduction method having excellent reduction efficiency as a metal ion reduction treatment method by using a composition for forming a conductor layer that does not contain an organic carbonyl compound or the blending amount of which is suppressed as much as possible. it can.

  Moreover, since the nitrogen-containing heterocyclic compound contained in the coating liquid 20 has an action of promoting the imidization reaction of the polyimide precursor resin, the coating liquid 20 is applied to the insulating substrate and then heated in the imidization step. When the polyimide precursor resin is imidized, the progress of imidization is prevented from becoming insufficient, and a polyimide resin layer having high adhesion to the insulating substrate can be formed.

  In addition, after applying the coating liquid 20 in a predetermined pattern on the insulating substrate 3 using the dispenser 30, the metal ions in the coating film 40 are reduced to form the metal deposit layer 9, thereby using metal fine particles. The sintering process required by the technical method is unnecessary, and poor conduction is unlikely to occur. Further, by directly applying the coating liquid 20 in a predetermined pattern using the dispenser 30, 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, it is possible to easily form the patterned conductor layer 5 even on a three-dimensional surface such as an uneven surface or a curved surface of the insulating substrate 3, for example. .

  In addition, according to the method for manufacturing a circuit board using the method for forming a conductor layer according to the present embodiment, it is possible to manufacture a highly reliable electronic component with excellent adhesion between the insulating base and the conductor layer at a high yield. There is an effect.

[Second Embodiment]
Next, with reference to FIG. 10, the formation method of the conductor layer based on the 2nd Embodiment of this invention is demonstrated. FIG. 10 is a flowchart showing an outline of the procedure of the method for forming a conductor layer according to the present embodiment. The method for forming a 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. In this case, the surface treatment can be performed, for example, by immersing the insulating substrate 3 in a solution of 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. In addition, the adhesion between the coating film 40 and the insulating substrate 3 can be improved by surface treatment with a silane coupling agent. Accordingly, it is possible to maintain the accuracy of the pattern formed by the coating film 40 and reduce the occurrence of defects in which the conductor layer 5 peels from the insulating base material 3. The surface treatment on the insulating base 3 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 °. It is good. 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 used for the surface treatment include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl). Aminopropyltrimethoxysilane, 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- Mercaptopropylmethyldimethoxysilane, 3-methyl Captopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxytriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxy Examples thereof include silane and 3-acryloxypropyltriethoxysilane.

  Moreover, when the insulating base material 3 is comprised with synthetic resin materials, such as a polyimide substrate and a PET (polyethylene terephthalate) 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, it is also effective to hydrolyze the polyimide resin on the surface of the insulating base material 3 by alkali treatment as a means for improving the adhesion between the coating film 40 and the insulating base material 3. It is. 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, while maintaining the pattern accuracy of the conductor layer 5, it is possible to reduce the occurrence of defects such as peeling of the conductor layer 5 due to a decrease in the adhesive force between the insulating base 3 and the polyimide resin layer 7. Other operations and effects in the present embodiment are the same as those in the first embodiment.

[Third Embodiment]
Next, with reference to FIG. 11 and FIG. 12, the formation method of the conductor layer based on the 3rd Embodiment of this invention is demonstrated. FIG. 11 is a flowchart showing an outline of the procedure of the method for forming a conductor layer according to the present embodiment. The method for forming a conductor layer according to the present embodiment includes steps S21 to S24 shown in FIG. The method for forming the conductor layer of the present embodiment can be performed in substantially the same manner as in the first embodiment except that the electroless plating step is not performed. Accordingly, steps S21 to S24 can be performed in substantially the same manner as steps S1, S2, S4, and S5 in the first embodiment, and only the differences will be described below.

  FIG. 12 is an explanatory view showing a cross-sectional structure of a main part of the conductor layer 5a formed by the method for forming a conductor layer according to the present embodiment. The conductor layer 5a of the present embodiment does not include the electroless plating layer 11, and covers the metal deposit layer 9 formed so as to cover the polyimide resin layer 7 on the insulating base 3, and the metal deposit layer 9 so as to cover it. The conductor layer 5a is formed by the electroplating layer 13 formed in the above. In addition, the conductor layer 5a may have other arbitrary layers.

  In this Embodiment which does not perform electroless plating, what has a metal compound density | concentration higher than the case where electroless plating is performed is used as the coating liquid 20 used at the coating film formation process of step S21. Specifically, the metal compound is in the range of 10 to 30 parts by weight, preferably in the range of 10 to 20 parts by weight, with respect to 100 parts by weight of the total of the polyimide precursor resin, the metal compound, and the viscosity modifier. It is preferable to use the coating liquid 20 contained as such. As described above, by using the coating solution 20 having a high metal compound concentration, it is possible to form a high-quality metal film (metal deposition layer 9) having almost no defects or unevenness in the reduction process of Step S22.

  In the present embodiment, the reason why the electroless plating step can be omitted is as follows. In the conventional method using the coating liquid 20 that does not contain a nitrogen-containing heterocyclic compound as a viscosity modifier, it is necessary to use a large amount of an organic carbonyl compound such as acetylacetone as the viscosity modifier. In this case, if the metal ion concentration in the coating liquid 20 increases, the amount of the organic carbonyl compound to be blended as a viscosity modifier increases accordingly. However, if the coating liquid 20 containing a large amount of the organic carbonyl compound is left for a long time, crystals of the organic carbonyl compound are precipitated in the liquid, and the handling of the coating liquid 20 becomes difficult.

  On the other hand, in the method of the present embodiment using the coating liquid 20 in which a nitrogen-containing heterocyclic compound such as pyridine is blended as a viscosity modifier, the nitrogen-containing heterocyclic compound is increased as the metal ion concentration in the coating liquid 20 is increased. However, even if it is left for a long time, almost no change in the state of the coating solution 20 is observed. Moreover, by using a nitrogen-containing heterocyclic compound, it becomes possible to keep the total amount of the viscosity modifiers markedly lower than when only an organic carbonyl compound is used. That is, when only a nitrogen-containing heterocyclic compound is blended as a viscosity modifier, or when a nitrogen-containing heterocyclic compound and an organic carbonyl compound are used in combination as a viscosity modifier, blending of the viscosity modifier in the coating solution 20 is performed. The amount and blending ratio can be greatly reduced as compared with the case where only the organic carbonyl compound is blended as a viscosity modifier. Due to the above two factors, the coating liquid 20 containing a nitrogen-containing organic compound can set the metal ion concentration higher than when it is not contained. As a result, it becomes possible to promote the precipitation of a sufficient amount of metal only by the reduction process of step S22, and a metal coating (metal deposition layer 9) having almost no defects and unevenness can be formed even if the electroless plating process is omitted. . In the present embodiment, omission of the electroless plating process not only saves the number of processes and processing time, but also eliminates complicated plating solution management and waste liquid treatment associated with electroless plating.

  Other operations and effects in the present embodiment are the same as those in the first embodiment. In the present embodiment as well, as in the second embodiment, a surface treatment process can be provided prior to the coating film forming process.

[Fourth Embodiment]
Next, with reference to FIG. 13, the formation method of the conductor layer based on 4th Embodiment is demonstrated. FIG. 13 is an explanatory diagram for explaining a coating film forming step in the present embodiment. In the first to third embodiments, the dispenser 30 is used as a coating means for the coating liquid 20 in the coating film forming step. However, in the present embodiment, minute droplets are ejected instead of the dispenser 30. A droplet discharge device 50 including a droplet discharge head 52 is used. In addition, since each process in this Embodiment can be performed similarly to each process of 1st-3rd Embodiment except the point which uses the droplet discharge apparatus 50 at a coating film formation process, it is the following. Only the differences will be described.

  In the present embodiment, in the coating film forming step, as shown in FIG. 13A, the coating liquid 20 is applied in a predetermined pattern on the insulating substrate 3 using the droplet discharge device 50. The droplet discharge device 50 includes a droplet discharge head 52 that can move relative to the insulating substrate 3 in the XY directions. The droplet discharge head 52 includes a discharge mechanism (not shown) using an ink jet printer technique, and as shown in FIG. 13B, the coating liquid 20 is made into fine droplets toward the insulating substrate 3. Discharge. That is, the droplet discharge head 52 includes, for example, a large number of fine nozzle holes 52a, and a pressure generating chamber (not shown) configured to be able to increase and decrease the internal volume by communicating with the nozzle holes 52a and contracting and expanding the piezo elements. And. Then, the piezoelectric element is driven by an electric drive signal from a control unit (not shown) to change the volume of the pressure generating chamber, and the application liquid 20 is discharged from each nozzle hole 52a using the increase in internal pressure generated at that time. It is configured such that it can be ejected toward the insulating substrate 3 as a fine droplet of about several picoliters to several microliters. As the droplet discharge head 52, it is possible to use a thermal type instead of the piezo type.

  As the coating solution 20, substantially the same coating solution 20 as in the first embodiment can be used. However, the viscosity of the coating liquid 20 when using the droplet discharge device 50 is preferably in the range of 10 to 20 cps. If the viscosity of the coating solution 20 is less than 10 cps, it may be difficult to control the target line width. On the other hand, if the viscosity of the coating liquid 20 exceeds 20 cps, the coating liquid 20 may be clogged in the nozzle hole 52a, making it impossible to apply. The viscosity of the composition for forming a conductor layer as the coating liquid 20 can be adjusted with a viscosity modifier.

  When the coating film 40 is formed using the droplet discharge device 50, 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 of the coating film 40 is adjusted by adjusting the viscosity of the coating liquid 20 (conductor layer forming composition), controlling the nozzle (discharge port) diameter, controlling the discharge pressure, controlling the drawing speed, or a combination thereof. Can be adjusted to the desired size. In the present embodiment, as described above, the viscosity of the coating liquid 20 is in the range of 10 to 20 cps, so that the pressure generation chamber (not shown) inside the droplet discharge head 52 of the droplet discharge device 50 is omitted. A fine pattern with a desired line width can be formed while preventing clogging in the nozzle holes 52a.

  After the coating liquid 20 is discharged onto the insulating substrate 3 from the droplet discharge head 52, it is dried. Drying can be performed under the same conditions as in step S1 in the first embodiment. Thus, the coating film 40 can be formed on the insulating base material 3 with a predetermined pattern.

  Other operations and effects in the present embodiment using the droplet discharge device 50 including the droplet discharge head 52 are the same as those in the first to third embodiments.

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

[Example 1]
To the polyimide precursor varnish A, 3.96 g of pyridine was added as a viscosity modifier and stirred for 30 minutes. To this mixture, a solution prepared by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. A complex solution 1 was prepared. The viscosity of this solution was 22,118 cps as measured with an E-type viscometer.

  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”). The glass substrate of the test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. On this glass substrate, the said polyimide precursor nickel complex solution 1 was apply | coated uniformly, and it dried for 30 minutes at 130 degreeC. The thickness of the coating film formed by coating and drying was 2 μm.

  Next, the glass substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate metallic nickel, thereby forming a Ni deposition layer on the surface of the coating film. did. 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 foil layer having a copper film thickness of 20 μm.

  The obtained copper foil layer-formed glass substrate 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 laminated glass substrate.

  After laminating a dry film resist on the copper foil layer of this copper laminated glass substrate, it was exposed to ultraviolet rays through a photomask, developed, and 50 μm pitch {wiring width / wiring spacing (L / S) = 20 μm / 30 μm} The resist pattern was formed. The copper foil layer of the formed wiring space part was removed by etching, and further, the lower polyimide resin layer was removed by etching to obtain a copper wiring-formed glass substrate.

[Example 2]
To the polyimide precursor varnish A, 3.96 g of pyridine and 1.00 g of acetylacetone were added as viscosity modifiers and stirred for 30 minutes. To this mixture, a solution obtained by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. Complex solution 2 was prepared. The viscosity of this solution was 8,960 cps as measured with an E-type viscometer.

  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% by weight γ-APS aqueous solution. The glass substrate of the test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. On this glass substrate, the said polyimide precursor nickel complex solution 2 was apply | coated uniformly, and it dried for 30 minutes at 130 degreeC. The thickness of the coating film formed by coating and drying was 2 μm.

  Next, the glass substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate metallic nickel, thereby forming a Ni deposition layer on the surface of the coating film. did. Next, after the glass substrate 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, the nickel layer used as the foundation | substrate of an electrolytic copper plating was formed by being immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd. product; Top Nicolon TOM-S (brand name)) for 30 seconds at 80 degreeC. .

Furthermore, 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 foil layer having a copper film thickness of 20 μm.

  After laminating a dry film resist on the copper foil layer of this copper laminated glass substrate, it was exposed to ultraviolet rays through a photomask, developed, and 50 μm pitch {wiring width / wiring interval (L / S) = 20 μm / 30 μm}. A resist pattern was formed. The copper foil layer of the formed wiring space part was removed by etching, and further, the lower polyimide resin layer was removed by etching to obtain a copper wiring-formed glass substrate.

[Example 3]
To the polyimide precursor varnish A, 3.96 g of pyridine and 2.00 g of acetylacetone were added as viscosity modifiers and stirred for 30 minutes. To this mixture, a solution prepared by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. A complex solution 3 was prepared. The viscosity of this solution was 780 cps as measured with an E-type viscometer.

  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% by weight γ-APS aqueous solution. The glass substrate of the test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. On the glass substrate, the polyimide precursor nickel complex solution 3 was drawn so as to be a straight line having a width of about 200 μm using a dispenser [CASTPRO II (trade name) manufactured by Sony Corporation; Dry at 130 ° C. for 30 minutes. The thickness of the coating film formed by drawing and drying was 2 μm.

  Next, the glass substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate metallic nickel, thereby forming a Ni deposition layer on the surface of the coating film. did. 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 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 glass substrate.

[Example 4]
To the polyimide precursor varnish A, 3.96 g of pyridine and 5.00 g of acetylacetone were added as viscosity modifiers and stirred for 30 minutes. To this mixture, a solution prepared by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. A complex solution 4 was prepared. The viscosity of this solution was 410 cps as measured with an E-type viscometer.

  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% by weight γ-APS aqueous solution. The glass substrate of the test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. On this glass substrate, the polyimide precursor nickel complex solution 4 was drawn so as to be a straight line having a width of about 200 μm using a dispenser, 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 is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate metallic nickel, and a Ni deposition layer is formed on the surface of the coating film. Formed. Next, after the glass substrate 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, the nickel layer used as the foundation | substrate of an electrolytic copper plating was formed by being immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd. product; Top Nicolon TOM-S (brand name)) for 30 seconds at 80 degreeC. .

Further, the nickel layer of the glass substrate is electroplated at a current density of 3.5 A / dm ² in an electrolytic copper plating bath to form a copper wiring with a copper film thickness of 20 μm. Obtained.

[Example 5]
To the polyimide precursor varnish A, 4.12 g of 1-methylimidazole was added as a viscosity modifier and stirred for 30 minutes. To this mixture, a solution prepared by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. A complex solution 5 was prepared. The viscosity of this solution was 570 cps as measured with an E-type viscometer.

  A test piece 10 cm × 10 cm (thickness 25 μm) of a polyimide film “Kapton EN” (trade name) manufactured by Toray DuPont was prepared. The polyimide precursor nickel complex solution 5 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 125 ° C. for 10 minutes. The thickness of the film formed by drawing and drying was 2 μm.

  Next, the polyimide substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate nickel metal, and form a Ni deposition layer on the surface of the coating film did. Next, after the polyimide substrate is washed with ion-exchanged water, it is 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.

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, 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 polyimide substrate.

[Example 6]
To the polyimide precursor varnish A, 4.12 g of 1-methylimidazole and 1.00 g of acetylacetone were added as viscosity modifiers, and stirred for 30 minutes. To this mixture, a solution prepared by dissolving 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP was added and stirred at room temperature for 1 hour, whereby a blue polyimide precursor nickel was formed as a conductor layer forming composition. A complex solution 6 was prepared. The viscosity of this solution was 430 cps as measured with an E-type viscometer.

  A test piece 10 cm × 10 cm (thickness 25 μm) of a polyimide film “Kapton EN” (trade name) manufactured by Toray DuPont was prepared. The polyimide precursor nickel complex solution 6 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 125 ° C. for 10 minutes. The thickness of the film formed by drawing and drying was 2 μm.

  Next, the polyimide substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions in the coating film to precipitate nickel metal, and form a Ni deposition layer on the surface of the coating film did. Next, after the polyimide substrate 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, the nickel layer used as the foundation | substrate of an electrolytic copper plating was formed by being immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd. product; Top Nicolon TOM-S (brand name)) for 30 seconds at 80 degreeC. .

Further, the nickel layer of the polyimide substrate is electroplated at a current density of 3.5 A / dm ² in an electrolytic copper plating bath to form a copper wiring with a copper film thickness of 20 μm. Obtained.

  The compositions and viscosities of the polyimide precursor nickel complex solutions 1 to 6 prepared in Examples 1 to 6 are collectively shown in Table 1.

[Comparative Example 1]
A solution of 3 g of commercially available nickel (II) acetylacetonate dihydrate dissolved in 20 ml of NMP was added to the polyimide precursor varnish A and stirred at room temperature for 1 hour, but gelation occurred and it did not become liquid. .

[Comparative Example 2]
By adding a solution of 3 g of commercially available nickel (II) acetylacetonate dihydrate in 20 ml of NMP and 3.7 g of acetylacetone as a viscosity modifier to the polyimide precursor varnish A, and stirring at room temperature for 1 hour, A green polyimide precursor nickel complex solution 8 was prepared as a conductor layer forming composition. The viscosity of this solution was 51,375 cps as measured with an E-type viscometer.

[Comparative Examples 3 to 7]
In the same manner as in Comparative Example 2 with the compositions shown in Table 2, polyimide precursor nickel complex solutions 9 to 13 were prepared as conductor layer forming compositions. The compositions of the polyimide precursor nickel complex solutions 7 and 8 prepared in Comparative Examples 1 and 2 and the viscosity of the polyimide precursor nickel complex solutions 7 to 13 of Comparative Examples 1 to 7 are also shown in Table 2.

  From the comparison of Table 1 and Table 2, the polyimide precursor nickel complex solutions of Examples 1 to 6 in which a nitrogen-containing heterocyclic compound (pyridine, 1-methylimidazole) was blended as a viscosity modifier contained a nitrogen-containing heterocyclic compound. It can be seen that, compared with the polyimide precursor nickel complex solutions of Comparative Examples 1 to 7 which are not, the thickening of the liquid is suppressed and gelation is also prevented.

  In Examples 2 to 4 and 6 in which a nitrogen-containing heterocyclic compound as a viscosity modifier and a known viscosity modifier (acetylacetone, triethylamine) were blended in combination, Comparative Example 2 in which only a known viscosity modifier was blended Compared to ˜7, not only a markedly excellent viscosity suppression effect was obtained, but also the total amount of viscosity modifier could be greatly reduced. The viscosity suppressing effect in Examples 1 to 6 hardly deteriorates even when stored for a long period of time, and can add excellent temporal stability to the polyimide precursor nickel complex solution by adding a small amount of a nitrogen-containing heterocyclic compound. Was also confirmed.

[Example 7]
After adding 3.96 g of pyridine and 9.4 g of acetylacetone as viscosity modifiers to the polyimide precursor varnish A and stirring for 30 minutes, a solution of 11 g of commercially available nickel (II) acetylacetonate dihydrate dissolved in 80 ml of NMP was added. By adding and stirring at room temperature for 1 hour, the blue polyimide precursor nickel complex solution 7 was produced as a composition for conductor layer formation. The viscosity of this solution was 2,000 cps as measured with an E-type viscometer.

  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% by weight γ-APS aqueous solution. The glass substrate of the test piece was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. On this glass substrate, the said polyimide precursor nickel complex solution 7 was apply | coated uniformly, and it dried for 30 minutes at 130 degreeC. The thickness of the coating film formed by coating and drying was 2 μm.

  Next, the glass substrate is immersed in a 10 mM sodium borohydride aqueous solution at 25 ° C. for 10 minutes to reduce Ni ions to precipitate metallic nickel, and nickel which becomes a base for electrolytic copper plating on the surface of the coating film A layer was formed. Next, it heated to 300 degreeC in nitrogen atmosphere, and the polyimide precursor resin was imidized over 5 minutes at the same temperature.

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 foil layer having a copper film thickness of 20 μm.

  After laminating a dry film resist on the copper foil layer of this copper laminated glass substrate, it was exposed to ultraviolet rays through a photomask, developed, and 50 μm pitch {wiring width / wiring spacing (L / S) = 20 μm / 30 μm} The resist pattern was formed. The copper foil layer of the formed wiring space part was removed by etching, and further, the lower polyimide resin layer was removed by etching to obtain a copper wiring-formed glass substrate.

[Example 8]
A test piece 10 cm × 10 cm (thickness 25 μm) of a polyimide film “Kapton EN” (trade name) manufactured by Toray DuPont was prepared. On the polyimide substrate, using a dispenser, the polyimide precursor nickel complex solution 7 produced in Example 7 was drawn so as to be a straight line having a width of about 200 μm, and then dried at 125 ° C. for 10 minutes. The thickness of the film formed by drawing and drying was 2 μm.

  Next, the polyimide substrate was immersed in a 10 mM aqueous solution of sodium borohydride at 25 ° C. for 10 minutes to reduce Ni ions to precipitate metallic nickel, thereby forming a nickel layer serving as a base for electrolytic copper plating. Next, it heated to 300 degreeC in nitrogen atmosphere, and the polyimide precursor resin was imidized over 5 minutes at the same temperature.

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.

[Example 9]
To the polyimide precursor nickel complex solution 6 produced in Example 6, 450 ml of NMP was further added to produce a polyimide precursor nickel complex solution 9. The viscosity of this solution was 15 cps as measured with an E-type viscometer.

  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% by weight γ-APS aqueous solution. The glass substrate was taken out from the γ-APS aqueous solution, dried, and heated at 150 ° C. for 5 minutes. As a droplet discharge device, an ink tank cartridge of a commercially available ink jet printer was prepared by filling the polyimide precursor nickel complex solution 9. And with this ink jet printer, the polyimide precursor nickel complex solution 9 was discharged onto the glass substrate and drawn on a straight line having a width of about 50 μm. Thereafter, the coating solution on the glass substrate was dried at a temperature of 130 ° C. for 10 minutes. The thickness of the coating film formed by drawing and drying was 0.5 μm.

  Next, the glass substrate is immersed in a 100 mM sodium borohydride aqueous solution at 50 ° C. for 3 minutes to reduce Ni ions to precipitate metallic nickel, and nickel which becomes a base for electrolytic copper plating on the surface of the coating film A layer was formed. Next, it heated to 300 degreeC in nitrogen atmosphere, and the polyimide precursor resin was imidized over 5 minutes at the same temperature. Then, the nickel layer used as the foundation | substrate of an electrolytic copper plating was formed by being immersed in an electroless nickel plating bath (Okuno Pharmaceutical Co., Ltd. product; Top Nicolon TOM-S (brand name)) for 30 seconds at 80 degreeC. .

Further, the nickel layer of the glass substrate is electroplated at a current density of 3.5 A / dm ² in an electrolytic copper plating bath to form a copper wiring with a copper film thickness of 20 μm. Obtained.

  In Examples 1 to 9 described above, the wet reduction method was employed in the reduction process, but reduction in reduction efficiency did not occur, and a high-quality nickel layer having almost no defects or unevenness was formed as the metal deposition layer. In particular, in Examples 7 and 8, the amount of the metal compound (nickel (II) acetylacetonate dihydrate) in the polyimide precursor nickel complex solution was set large, and the nickel ion concentration was increased, so that It was possible to form a conductor layer by directly electroplating the nickel layer (metal deposition layer) without requiring any electrolytic plating process. By omitting the electroless plating process, not only the number of processes and the processing time are saved, but also a great practical advantage that complicated plating solution management and waste liquid treatment associated with electroless plating is not required.

  In addition, this invention is not limited to said each embodiment, A various change is possible. For example, in the first to fourth embodiments, the imidization process is performed prior to the electroless plating process or the electroplating process. However, as illustrated in, for example, Example 1 and Example 3 An imidization process can also be implemented after a plating process.

  Moreover, in the said 1st-4th embodiment, it is also possible to provide the water washing process (cleaning process) by a pure water, ion-exchange water, etc., respectively after a reduction process and / or an electroless-plating process. .

  In the first to fourth embodiments, the droplet discharge device 50 including the dispenser 30 and the droplet discharge head 52 is used as means for applying the coating liquid 20 to the insulating substrate 3 in the coating film forming step. The example used is explained. However, since the composition for forming a conductor layer of the present invention uses a nitrogen-containing heterocyclic compound as a viscosity modifier, in addition to the above, the insulating base material can be applied by various application means such as screen printing, bar coater, spin coater, etc. The coating method is not limited. Furthermore, as exemplified in the above-mentioned Example 1, Example 2, etc., in the coating film forming step, a coating film is formed by applying a coating liquid on the entire surface of the insulating base (so-called “solid coating”), After the electroplating, the conductor layer may be processed into a predetermined pattern by providing a photolithography process and a chemical etching process.

It is explanatory drawing which shows the structure of the circuit board to which the formation method of the conductor layer which concerns on the 1st Embodiment of this invention is applied. 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 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 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 metal deposit layer 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 conductor layer after an electroplating process. It is a flowchart which shows the outline | summary of the procedure of the formation method of the 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 conductor layer which concerns on the 3rd Embodiment of this invention. It is explanatory drawing for demonstrating the cross-section of the conductor layer formed by the formation method of the conductor layer which concerns on the 3rd Embodiment of this invention. It is explanatory drawing for demonstrating the coating film formation process in the formation method of the conductor layer which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit board, 3 ... Insulation base material, 5 ... Conductor layer, 7 ... Polyimide resin layer, 9 ... Metal deposit layer, 11 ... Electroless plating layer, 13 ... Electroplating layer, 20 ... Coating liquid, 30 ... Dispenser, 40, 40a ... coating film, 50 ... droplet discharge device.

Claims (5)

A composition for forming a conductor layer used as a coating solution for forming a conductor layer on an insulating substrate,
A polyimide precursor resin;
A metal compound;
A nitrogen-containing heterocyclic compound as a viscosity modifier;
A composition for forming a conductor layer.   The composition for forming a conductor layer according to claim 1, wherein the viscosity modifier contains an organic carbonyl compound together with the nitrogen-containing heterocyclic compound.   The composition for forming a conductor layer according to claim 1 or 2, wherein the nitrogen-containing heterocyclic compound is a tertiary amino compound. A method for forming a conductor layer that forms a conductor layer on an insulating substrate,
A coating film forming step of applying the composition for forming a conductor layer according to any one of claims 1 to 3 on a surface of the insulating base material as a coating liquid, and drying to form a coating film;
A reduction step of reducing metal ions present in the coating film and forming a metal deposition layer as the conductor layer on the surface of the coating film;
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 conductor layer, comprising: A method of manufacturing a circuit board comprising an insulating substrate and a conductor layer formed on the insulating substrate,
A method for manufacturing a circuit board, wherein the conductor layer is formed by the method for forming a conductor layer according to claim 4.

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