JP2010080878A - Printed circuit board and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the bleeding-out of a ring dimethylsiloxane oligomer from a protection layer including a photosensitive siloxane polyimide resin composition in a printed circuit board, and to achieve an excellent plating resistance. <P>SOLUTION: A protection layer including a thermosetting resin of a photosensitive siloxane polyimide resin composition containing a siloxane polyimide resin prepared by imidization of tetracarboxylic acid dianhydride, siloxane diamines containing diphenylsilirene unit, and non-siloxane-containing diamines, a crosslinking agent, and a photo-acid-generating agent is formed at least on a portion of the copper or copper alloy wiring pattern of a printed circuit board. A specific amount of a kind selected from a group containing a liquid epoxy resin, benzoxazines, and resoles is used as the crosslinking agent. A specific amount of photo-acid-generating agent is used as the photosensitising agent. The surface of the copper or copper alloy wiring pattern of the printed circuit board is textured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printed wiring board having a protective layer formed from a photosensitive siloxane polyimide resin composition and a method for producing the same.

  Aromatic polyimide resin formed by imidizing aromatic tetracarboxylic acid and aromatic diamine is widely used as an interlayer insulation film and coverlay material for electronic parts because of its excellent heat resistance and insulation. However, excellent flexibility and adhesiveness are required for such aromatic polyimide resins. For this reason, the use of siloxane polyimide resins in which a part of the aromatic diamine is replaced with siloxane diamine and the siloxane skeleton is introduced into the polyimide skeleton is increasing.

  However, since siloxane diamine, which is a raw material of siloxane polyimide resin, contains cyclic dimethylsiloxane oligomers that do not have amino groups as impurities, the manufactured siloxane polyimide resin can be applied to electronic components as interlayer insulation films, coverlays, etc. In this case, when the electronic component is put into a heat treatment process such as a solder reflow process, the cyclic dimethylsiloxane oligomer generated as an outgas on the surface of the interlayer-line insulating film or the coverlay is reattached or bleeded out, resulting in a contact failure in the electronic component. In addition, there is a problem that a decrease in conductivity, a decrease in adhesive strength, and the like occur. In this specification, “bleed out” refers to a phenomenon in which a substance contained in a solid layer such as a film moves to the surface of the solid layer and liquefies or solidifies there, or volatilizes and diffuses there. means.

  In order to solve this problem, a diamine compound containing at least diaminosiloxane as a diamine component and a tetracarboxylic dianhydride are subjected to an imidization reaction in toluene or an ether solvent. A method has been proposed in which the solvent to be discharged is discharged out of the system and the solvent is replenished (Patent Document 1). According to this method, since the cyclic dimethylsiloxane oligomer has a relatively low boiling point compared to the solvent, it is discharged out of the system together with the volatile solvent, and a siloxane polyimide varnish with a reduced concentration of the cyclic dimethylsiloxane oligomer is obtained. It is said that.

JP 2004-263058 A

  However, in the method of Patent Document 1, since the solvent volatilized at normal pressure is discharged out of the system, dimethylsiloxane oligomers up to hexamers can be considerably removed, but dimethylsiloxane oligomers more than heptamers are sufficiently removed. There was a problem that could not be removed. For this reason, the siloxane polyimide varnish obtained by the method of Patent Document 1 is mixed with a photosensitizer to impart photosensitivity, and is also widely used as a crosslinker for polyimide, silane coupling agent, epoxyamine, solid epoxy When a resin or the like is blended, the resulting photosensitive siloxane polyimide resin composition is formed on a printed wiring board, patterned and cured from a thin protective layer (plating resist, solder resist, etc.), and impurities. There is a problem that it is still difficult to suppress bleeding of a certain cyclic dimethylsiloxane oligomer.

  In addition, for a printed wiring board having a protective layer formed from such a photosensitive siloxane polyimide resin composition, electroless is applied to the copper or copper alloy wiring pattern region (opening area) not covered with the protective layer. Or, the plating process is applied to grow the electrolytic plating layer, but since the adhesion between the protective layer and the copper or copper alloy wiring pattern is not sufficient, discoloration may occur around the opening area. There has been a demand for improved plating resistance.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and is a printed wiring board having a protective layer made of a photosensitive siloxane polyimide resin composition, which is an impurity which is an impurity from the protective layer. It is an object of the present invention to provide a printed wiring board in which bleedout of dimethylsiloxane oligomer is sufficiently suppressed and exhibits excellent plating resistance.

  The present inventors prepared a siloxane polyimide resin by using a siloxane diamine having a diphenylsilylene unit as a diamine component, and further used a photosensitive siloxane polyimide resin composition containing a specific kind and amount of a crosslinking agent. By forming a protective layer, bleeding out of the cyclic dimethylsiloxane oligomer can be suppressed, and if the copper or copper alloy wiring pattern of the wiring board is subjected to surface roughening treatment in advance, the protective layer formed thereon The inventors found that the plating resistance can be improved and completed the present invention.

That is, the present invention is a photosensitive resin containing a siloxane polyimide resin obtained by imidizing a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and a siloxane-free diamine, a crosslinking agent, and a photoacid generator. A protective layer made of a thermosetting product of a functional siloxane polyimide resin composition is the printed wiring board formed on at least a part of the copper or copper alloy wiring pattern of the printed wiring board,
At least one selected from the group consisting of liquid epoxy resins, benzoxazines and resols is used as a crosslinking agent, 1 to 20 parts by mass with respect to 100 parts by mass of a siloxane polyimide resin, and a photoacid generator is used as a photosensitive agent. Use 5 to 30 parts by mass with respect to 100 parts by mass of siloxane polyimide resin,
Provided is a printed wiring board characterized in that the surface of a copper or copper alloy wiring pattern is subjected to surface roughening treatment.

Further, the present invention is a method for manufacturing the above-described printed wiring board,
The surface of the copper or copper alloy wiring pattern on the printed wiring board is surface roughened,
A siloxane polyimide resin obtained by imidizing a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and a siloxane-free diamine on at least a part of a copper or copper alloy wiring pattern subjected to surface roughening treatment; A photosensitive siloxane polyimide resin composition containing a crosslinking agent and a photoacid generator is formed, exposed, developed, patterned, and thermally cured by post-baking to form a protective layer. In the method of manufacturing a printed wiring board that performs electroless plating or electrolytic plating according to
At least one selected from the group consisting of liquid epoxy resins, benzoxazines and resols is used as a crosslinking agent, 1 to 20 parts by mass with respect to 100 parts by mass of a siloxane polyimide resin, and a photoacid generator is used as a photosensitive agent. Provided is a production method using 5 to 30 parts by mass with respect to 100 parts by mass of a siloxane polyimide resin.

  According to the present invention, a siloxane diamine having a diphenylsilylene unit is used as a diamine component, and a protective layer such as a thin film made of a photosensitive siloxane polyimide resin composition has a three-dimensional structure with a specific thermosetting crosslinking agent. As a result, the cyclic dimethylsiloxane oligomer, which is an impurity, is trapped in the three-dimensional structure. As a result, bleeding out of the cyclic dimethylsiloxane oligomer can be prevented or suppressed, and further, good plating resistance can be obtained by thermosetting. Is obtained. In addition, since the acid generator is contained in a specific amount as the photosensitive agent, the siloxane polyimide resin composition becomes positive photosensitive and can be patterned by exposure and alkali development.

  Moreover, since the copper or copper alloy wiring pattern of the printed wiring board has been subjected to surface roughening in advance, the adhesion between the copper or copper alloy wiring pattern and the protective layer can be improved, and the protective layer is resistant to plating. It becomes possible to improve the property.

  The photosensitive siloxane polyimide resin composition for forming the protective layer of the printed wiring board of the present invention is a siloxane obtained by imidizing a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and a siloxane-free diamine. 100 parts by mass of a polyimide resin, 1 to 20 parts by mass of a crosslinking agent selected from the group consisting of a liquid epoxy resin, benzoxazines and resols, and 5 to 30 parts by mass of a photoacid generator as a photosensitive agent contains.

  First, the siloxane polyimide resin that is the main component of the photosensitive siloxane polyimide resin composition will be described. Since this siloxane polyimide resin uses diaminosiloxane having a diphenylsilylene unit as the diamine component, the amount of cyclic dimethylsiloxane oligomer generated can be reduced.

  Specific examples of the tetracarboxylic dianhydride that is a structural unit of the siloxane polyimide resin used in the present invention include pyromellitic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 3,4,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride, 9, 9-bis (3,4-dicarboxyphenyl) fluorene dianhydride, 9,9-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorene dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, bicyclo [2. .2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, ethylene glycol bistrimellitic dianhydride, 2,2-bis (4- (3,4-dicarboxyphenoxy) And phenyl) propane dianhydride. Among these, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride can be preferably used.

  Moreover, as a siloxane diamine which becomes a structural unit of the siloxane polyimide resin used in the present invention, a compound having at least a dimethylsilylene skeleton in the molecule, and those conventionally used for siloxane modification of polyimide resins can be used. . Especially, what has the structure of the following formula | equation (1) can be used preferably from the point of a flame retardance and compatibility ensuring.

  In formula (1), n is an integer of 1-30, preferably an integer of 1-20, and m is an integer of 1-20, preferably an integer of 1-10. Since m is 1 or more, the siloxane diamine of the formula (1) has a diphenylsilylene skeleton, and the flame retardancy of the siloxane polyimide resin is improved. And since m is 1 or more, it becomes possible to suppress the bleeding out of the cyclic dimethylsiloxane oligomer which is an impurity to some extent. Specific examples of such siloxane diamine include X-22-9409 (m> 1) manufactured by Shin-Etsu Chemical Co., Ltd. As the siloxane diamine, those having an amino group protected by a carbamate type such as a tert-butoxycarbonyl group, an imide type such as a phthaloyl group, or a sulfonamide type such as a p-toluenesulfonyl group can be used.

  As the siloxane-free diamine which is a constituent unit of the siloxane polyimide resin used in the present invention, a diamine having no dimethylsilylene skeleton and diphenylsilylene skeleton in the molecule can be used, and specific examples thereof include 3, 3 '-Diamino-4,4'-dihydroxydiphenyl sulfone, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) propane, 3,3'-diamino-4,4'-dihydroxydiphenylmethane, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,4-diaminophenol, 9,9-bis (3-amino-4-hydroxy Diaminophenol derivatives such as phenyl) fluorene; p-phenylenediamine, 4,4 ′ Diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, 1,3-bis (4-aminophenoxy) benzene, 2, 2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 1,3-bis (3-aminophenoxy) benzene, 4,4'-diaminobenzanilide, 5,5'-methylene-bis (anthra Nickic acid), 9,9-bis [4- (4-aminophenoxyphenyl)] fluorene, 9,9-bis (4-aminophenoxy) fluorene, 4,4'-diaminodiphenyl sulfone, 3,4'-diamino Diphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 4,4'-bis ( -Aminophenoxy) aromatic diamines such as biphenyl, 1,4-bis (4-aminophenoxy) benzene, o-tolidine sulfone; trans-1,4-cyclohexanediamine, cis-1,4-cyclohexanediamine, 4,4 Examples include, but are not limited to, aliphatic diamines such as' -methylenebis (cyclohexylamine), but are preferably diaminophenol derivatives, particularly 3,3'-diamino-4,4'-dihydroxy. Mention may be made of diphenylsulfone.

  The siloxane polyimide resin used in the present invention is produced by imidization reaction of a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and, if necessary, a siloxane-free diamine in a solvent under reflux conditions. However, it can also be obtained by a production method having the following steps (a) and (b).

Step (a)
First, a tetracarboxylic dianhydride and a siloxane diamine having a diphenylsilylene unit are subjected to an imidization reaction under a reflux condition to obtain a reaction mixture containing an acid anhydride-terminated siloxane imide oligomer.

  In order to obtain an acid anhydride-terminated siloxane imide oligomer, the molar amount of the first tetracarboxylic dianhydride may be increased as compared with siloxane diamine. However, if the amount of siloxane diamine used is too small relative to 1 mol of all tetracarboxylic dianhydrides, it tends to be difficult to maintain adhesion and flexibility, and if too large, heat resistance tends to decrease. Since it exists, Preferably it is 0.1-0.9 mol, More preferably, it is 0.3-0.8 mol.

  In the step (a), the reason for carrying out the imidation reaction under reflux conditions is to remove imidized water using a Dean-Stark separation tube or the like. Therefore, as the solvent, a solvent that is refluxed at a temperature at which an imidization reaction between tetracarboxylic dianhydride and siloxane diamine occurs and can separate water by azeotropy is used. Examples of such a solvent include glymes such as diglyme and triglyme, ether solvents such as dioxane and tetrahydrofuran, lactone solvents such as γ-butyrolactone and γ-valerolactone, and mixtures thereof. In addition, an aromatic hydrocarbon solvent such as toluene, xylene, benzene and mesitylene and an amide solvent such as N-methyl-2-pyrrolidone may be used in combination as long as the effects of the invention are not impaired. In this step (a), preferably a mixed solvent of glymes and an aromatic hydrocarbon solvent, particularly triglyme, and at least one selected from the group consisting of benzene, toluene, xylene and mesitylene from the viewpoint of reflux temperature and the like. A mixed solvent (w / w = 1 / (0.1-10)) can be preferably used.

  The amount of solvent used in step (a) varies depending on the type of solvent and reaction substrate, but if it is too small, it will cause poor monomer dispersion and decrease in reflux efficiency. If it is too large, the heat of vaporization of the solvent will increase and the temperature in the reaction vessel will increase. Therefore, the total mass of tetracarboxylic dianhydride and siloxane diamine is preferably used in an amount of 5 to 60% by mass.

  The reaction temperature of the imidation reaction varies depending on the type and amount of the solvent and reaction substrate, but if it is too low, the imidization reaction cannot be completed, and if it is too high, side reactions other than the imidization reaction may occur. Preferably it is 150-220 degreeC, More preferably, it is 160-200 degreeC. The reaction time is the time required to remove the theoretical amount of imidized water, and is usually 0.5 to 12 hours, preferably 1 to 8 hours.

  In addition, in the imidization in the step (a), a tertiary amine such as triethylamine, a basic catalyst such as aromatic isoquinoline and pyridine, and an acid catalyst such as benzoic acid and parahydroxybenzoic acid are added as necessary. May be.

Step (b)
After completion of the reaction in the step (a), a siloxane-free diamine is added to the solution of the acid anhydride-terminated siloxane imide oligomer obtained in the step (a), and the siloxane-free diamine and the acid anhydride-terminated siloxane imide oligomer are added. An imidization reaction is performed to obtain a siloxane polyimide resin. In this case, you may add the same or different tetracarboxylic dianhydride as what was used previously with a siloxane non-containing diamine as needed. Moreover, you may add a solvent as needed. This makes it possible to adjust the polyimide solid content concentration. As the solvent, those that can be used in step (a) can be used. In particular, when a siloxane polyimide resin is used as a varnish, in order to prevent polyimide precipitation due to moisture absorption during coating, an ether solvent, a lactone solvent, a nonpolar solvent, etc., which are relatively low hygroscopic solvents, or Can be used as a mixture. In particular, in this step (b), a mixed solvent of triglyme (also known as triethylene glycol dimethyl ether) and γ-butyrolactone (w / w = 1 / (0.1-10)) can be preferably used.

  The amount of the siloxane-free diamine used is preferably such that the number of moles combined with the siloxane diamine is 1 mol of all tetracarboxylic dianhydrides in order to ensure a molecular weight for obtaining a protective layer having sufficient mechanical properties. Is an amount of 0.1 to 0.9 mol, more preferably 0.3 to 0.8 mol.

  In the case of imidization in the step (b), as in the case of the step (a), a basic catalyst such as a tertiary amine such as triethylamine, aromatic isoquinoline or pyridine, benzoic acid, An acid catalyst such as parahydroxybenzoic acid may be added.

  Regarding the imidization reaction temperature in the step (b), in the step (b), when an acid dianhydride or diamine component having a polar group is used, the viscosity of the siloxane polyimide resin generated by the Weiselberg effect increases, A phenomenon of winding around the stirring rod may occur. In order to avoid an increase in the viscosity of the produced siloxane polyimide resin, it is preferable that water be present in the reaction system. In this case, if the amount of water is too small, the risk of thickening increases, and if it is too large, the molecular weight of the polyimide may decrease, so water is added at a ratio of 0.01 to 1.1% by mass in the reaction mixture. Preferably it is present.

  The reaction temperature at the time of imidation in the step (b) varies depending on the type and amount of the solvent and reaction substrate, but if it is too low, the imidization reaction is not completed, and if it is too high, side reactions other than the imidization reaction occur. Since there is a possibility, Preferably it is 150-220 degreeC, More preferably, it is 160-200 degreeC. The reaction time is usually 0.5 to 12 hours, preferably 1 to 8 hours. Thereby, the siloxane polyimide resin with little content of cyclic dimethylsiloxane oligomer is obtained in a varnish state.

  Next, the crosslinking agent used in the photosensitive siloxane polyimide resin composition will be described. Literally, the crosslinking agent itself is polymerized and cured by heating to form a three-dimensional crosslinked structure. For this reason, the cyclic dimethylsiloxane oligomer as an impurity can be confined in the three-dimensional structure, and the bleed-out can be suppressed or prevented.

  Examples of such a crosslinking agent include at least one selected from the group consisting of liquid epoxy resins, benzoxazines, and resoles that are compatible with siloxane polyimide resins. In particular, from the viewpoint of preventing volatilization / diffusion of cyclic siloxane, a liquid epoxy resin and a benzoxazine can be used together, or a liquid epoxy resin, a benzoxazine and a resole can be used together. Here, the polymerization of the liquid epoxy resin proceeds with the amino group remaining in the siloxane polyimide resin as an anionic polymerization starting point by heating. Polymerization of benzoxazines proceeds by heating to open the oxazine ring to produce a methylenium cation and a phenolic oxonium anion, and the methylenium cation proceeds by nucleophilic substitution polymerization on the benzene ring. In the case of resols, the phenolic hydroxyl group proceeds by dehydration condensation polymerization of the benzene ring by heating.

  Such liquid epoxy resins and resols are preferably 1 to 100,000 mPa.s so as to have good compatibility with the siloxane polyimide resin. s, more preferably 1 to 50000 mPa · s. Here, the viscosity is a value measured with a B-type viscometer at 25 ° C. On the other hand, benzoxazines are usually solid at room temperature, but if the softening point is too high, the compatibility with the siloxane polyimide resin is lowered, so that those having a temperature of about 100 ° C. or less are preferable.

  Preferred specific examples of the liquid epoxy resin used as the crosslinking agent include bisphenol F type epoxy resins (jER807, Japan Epoxy Resin Co., Ltd.), bisphenol A type epoxy resins (jER828, Japan Epoxy Resin Co., Ltd.), alicyclic type. Examples thereof include epoxy resins (Celoxide 2021, Daicel Chemical Industries, Ltd.), glycidylamine type epoxy resins (iER604, Japan Epoxy Resin Co., Ltd .; GAN, Nippon Kayaku Co., Ltd., etc.). Among these, bisphenol F type epoxy resin and bisphenol A type epoxy resin can be preferably used from the viewpoint of easy availability.

  Preferable specific examples of benzoxazines used as a crosslinking agent include bisphenol S-type benzoxazine of the following formula (1), bisphenol F-type benzoxazine of formula (2), bisphenol A-type benzoxazine of formula (3) ( All include Konishi Chemical Industry Co., Ltd.). Among these, bisphenol F-type benzoxazine can be preferably used from the viewpoint of easy availability.

  Further, preferred specific examples of resoles used as a crosslinking agent include alkali resole resins obtained using alkali metal or alkaline earth metal hydroxides as catalysts, ammonia resole resins obtained using ammonia as a catalyst, Examples thereof include a high ortho resole resin obtained by using a divalent metal salt as a catalyst. Among these, alkali resole resins can be preferably used from the viewpoint of availability.

  The content of the crosslinking agent in the photosensitive siloxane polyimide resin composition used in the present invention is 1 to 20 parts by mass, preferably 1 to 15 parts by mass, more preferably 1 to 100 parts by mass of the siloxane polyimide resin. -10 parts by mass. If the content of the crosslinking agent is below this range, the effect of suppressing the volatilization / diffusion of the cyclic siloxane becomes insufficient, and if it exceeds, the flexibility tends to be poor and the film tends to be hard, which is not preferable.

  In addition, when a liquid epoxy resin and benzoxazines are used together as a crosslinking agent, benzoxazines are preferably used at a ratio of 0.5 to 10 parts by mass with respect to 1 part by mass of the liquid epoxy resin. This is because if the amount of benzoxazine is too small, the effect of suppressing the volatilization / diffusion of the cyclic siloxane is insufficient, and if it is too large, the flexibility tends to be poor and the film tends to be hard. Moreover, when using together a liquid epoxy resin, benzoxazines, and resoles simultaneously, preferably 0.5-10 mass parts of benzoxazines and preferably 0.5-resoles of benzoxazines per 1 mass part of the liquid epoxy resin. It is used at a ratio of 10 parts by mass. This is because if the amount of resol is too small, the effect of suppressing the volatilization / diffusion of cyclic siloxane is insufficient, and if it is too large, the flexibility tends to be poor and the film tends to be hard.

  Next, the photoacid generator used in the photosensitive siloxane polyimide resin composition will be described. The photoacid generator gives the composition the property that when the thin film of the siloxane polyimide resin composition containing it is exposed to ultraviolet rays or the like, it decomposes in the thin film to generate an acid, and the thin film can be developed with an alkali. It is used as a photosensitizer.

  Such photoacid generators include diazonium salts, diazoquinone sulfonic acid amides, diazoquinone sulfonic acid esters, diazoquinone sulfonates, nitrobenzyl esters, onium salts, halides, halogenated isocyanates, halogenated triazines, bis Examples include arylsulfonyldiazomethane and disulfone. Especially, the o-quinonediazide compound which has the effect which suppresses the water solubility of an unexposed part can be used preferably. Specific examples of o-quinonediazide compounds include 1,2-benzoquinone-2-azido-4-sulfonic acid ester or sulfonic acid amide, 1,2-naphthoquinone-2-diazide-5-sulfonic acid ester or sulfonic acid amide, Examples include 1,2-naphthoquinone-2-diazide-4-sulfonic acid ester or sulfonic acid amide. These include, for example, 1,2-benzoquinone-2-azido-4-sulfonyl chloride, 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride, 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride, and the like. The o-quinonediazide sulfonyl chloride and polyhydroxy compound or polyamine compound can be obtained by condensation reaction in the presence of a dehydrochlorination catalyst.

  Content of the photo-acid generator in the photosensitive siloxane polyimide resin composition used by this invention is 5-30 mass parts with respect to 100 mass parts of siloxane polyimide resins, Preferably it is 5-20 mass parts. If the content of the photoacid generator is below this range, sufficient sensitivity cannot be obtained, and if it exceeds, the heat resistance of the resin composition tends to decrease, such being undesirable.

  In the photosensitive siloxane polyimide resin composition used in the present invention, known additives such as a metal deactivator, an antifoaming agent, a rust preventive, and an organic solvent can be blended as necessary.

  The photosensitive siloxane polyimide resin composition used in the present invention can be produced by uniformly mixing a siloxane polyimide resin, a crosslinking agent, a photosensitive agent, other additives and a solvent by a conventional method.

  The protective layer (plating resist, solder resist, etc.) obtained by thermally curing the photosensitive siloxane polyimide resin composition used in the present invention has a large cyclic dimethylsiloxane oligomer bleed-out unlike conventional siloxane polyimide resins. It will be suppressed.

  The printed wiring board of the present invention is a printed wiring board in which a protective layer, which is a thermoset of the photosensitive siloxane polyimide resin composition described above, is formed on at least a part of a copper or copper alloy wiring pattern of the printed wiring board. A surface of the copper or copper alloy wiring pattern is roughened. For this reason, the minute unevenness | corrugation used as the anchor of a protective layer is formed in the surface of a copper or copper alloy wiring pattern, As a result, the adhesiveness of a protective layer increases and plating resistance improves.

  As such surface roughening treatment, wet blast treatment using an aqueous slurry of inorganic fine particles and so-called chemical polishing treatment using a chemical etching agent for copper or a copper alloy are preferably exemplified. The level of roughening is preferably Ra (average surface roughness) of 50 to 500 nm from the viewpoint of compatibility with developability.

  Examples of the inorganic fine particles serving as an abrasive dispersed in the aqueous slurry used in the wet blast treatment include alumina particles, silica particles, zirconia particles, and resin particles. Among these, alumina particles can be preferably used from the viewpoint of availability.

  If the average particle size of these inorganic fine particles is too small, it will be difficult to disperse in the aqueous slurry, and if it is too large, it will be difficult to form subtle irregularities on the surface of the copper or copper wiring pattern. Preferably it is 2-100 micrometers.

  These inorganic fine particles are used as an aqueous slurry. In addition to water, a water-miscible organic solvent (methanol, ethanol, acetone, etc.) can be used in combination. Moreover, a well-known dispersion stabilizer can be mix | blended with aqueous slurry.

  In the wet blast treatment, it is preferable that the aqueous slurry is jetted at a speed of usually 80 to 200 m / sec toward the printed wiring board with compressed air.

  A preferable chemical polishing treatment is one using an etching agent containing sulfuric acid, a hydrogen peroxide solution, an azole rust inhibitor, and an aromatic hydrogen peroxide decomposition inhibitor. Here, examples of the azole rust preventive include imidazole compounds, triazole compounds, and tetrazole compounds. As the aromatic hydrogen peroxide decomposition inhibitor, benzenesulfonic acids such as toluenesulfonic acid and phenolsulfonic acid can be added. In addition, by such a chemical polishing treatment, an azole rust preventive agent or an aromatic hydrogen peroxide decomposition inhibitor is chemically or physically bonded to the surface of copper or the same alloy and a protective layer that is an organic substance. It is considered that the adhesion is further improved.

  If the content of sulfuric acid in the etching solution (1 liter) is too small, the etching rate is slow, and if it is too large, an effect commensurate with the blending amount cannot be obtained, so it is preferably 50 to 300 g. If the content of hydrogen peroxide in the etching solution is too small, the etching rate is slow, and if it is too large, uniform etching becomes difficult. Therefore, the content is preferably 10 to 30% by mass per 100 g of sulfuric acid.

  In the chemical polishing treatment, it is preferable to spray the copper or copper alloy wiring pattern surface of the printed wiring board or immerse the printed wiring board in the stirred etching liquid while maintaining the etching liquid at room temperature to 50 ° C.

  The printed wiring board of the present invention can be applied to so-called flexible printed wiring boards, glass epoxy wiring boards, laminated printed wiring boards and the like. Also, as the copper or copper alloy pattern, a pattern of any thickness formed by a conventional semi-additive method or built-up method can be applied.

  Moreover, the formation position of the protective layer of a printed wiring board is on at least one part of a copper or copper alloy wiring pattern. When the wiring pattern is exposed, since there is a boundary between the protective layer and the wiring pattern, it is easy to confirm the effect of improving the plating resistance of the protective layer. When the protective layer covers the entire surface of the wiring pattern, it cannot be assumed that there is a boundary between them, so that it is difficult to confirm the effect of improving the plating resistance.

  The printed wiring board of the present invention described above can be manufactured as follows. First, the surface of the copper or copper alloy wiring pattern of the printed wiring board is subjected to surface roughening as described above. Next, using the bar coater, roll coater, comma coater, or screen printer on the surface roughened wiring pattern, the photosensitive siloxane polyimide resin composition of the present invention is applied and dried at 50 to 100 ° C. Then, the film is exposed by irradiating active energy rays such as ultraviolet rays through an exposure mask, and the exposed portion is removed and patterned by alkali development using an aqueous sodium hydroxide solution, and then 120 to 250 ° C. The protective layer can be formed by heat-curing with a post-bake that is heated, and if necessary, electroless plating such as electroless nickel plating can be applied or electrolytic plating can be performed.

  Hereinafter, the present invention will be specifically described by way of examples.

Reference Example 1 (photosensitive siloxane polyimide resin composition containing a crosslinking agent)
(1) Manufacture of siloxane polyimide resin In a reaction vessel of a polyimide resin synthesizer equipped with a Dean-Stark trap, 862.65 g (0.639 mol) of diaminosiloxane (diaminodiphenyl / dimethylsiloxane (amine equivalent 675 g / mol), product Name: X-22-9409, manufactured by Shin-Etsu Chemical Co., Ltd.) and 363.6 g (1.01 mol) of 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride (Ricacid DSDA, Shin Nippon) Rika Co., Ltd .; purity 99.6%), 547 g of triglyme, and 200 g of toluene were added, and the mixture was sufficiently stirred for 2 hours. Thereafter, the temperature was raised to 185 ° C., the temperature was maintained for 2 hours, and the reaction solution was stirred under reflux while collecting water with a Dean-Stark trap.

The obtained reaction mixture was applied on a silicon wafer from which the oxide film was removed, dried at 100 ° C. for 10 minutes, and the terminal functional group was identified by the FT-IR transmission method. Absorption of imide carbonyl appeared in the vicinity of 1780 cm ⁻¹ , and absorption of cyclic acid anhydride carbonyl stretching vibration was confirmed in the vicinity of 1860 cm ⁻¹ , thereby confirming the formation of an acid anhydride-terminated siloxane oligomer.

  The reaction mixture was allowed to cool to 80 ° C., and 101.44 g (0.361 mol) of 3,3′-diamino-4,4′-dihydroxydiphenyl sulfone (BSDA, manufactured by Konishi Chemical Industries, Ltd .; purity 99.7%) And stirred at room temperature for 12 hours. After stirring, the temperature was raised to 185 ° C., and the mixture was heated and stirred at that temperature for 2 hours. Then, it cooled to room temperature and obtained the varnish of the diphenylsilylene unit containing siloxane polyimide resin.

(2) Preparation of photosensitive siloxane polyimide resin composition To varnish of siloxane polyimide resin, 10 phr of photosensitizer (4NT-300, Toyo Gosei Co., Ltd.), metal deactivator (rust inhibitor) (CDA-10, ADEKA Co., Ltd.) 0.3 phr, liquid epoxy resin (jER807, Japan Epoxy Resin Co., Ltd.) 0.5 phr as a cross-linking agent, benzoxazine (BF-BXZ, Konishi Chemical Co., Ltd.) 5 phr, and resole resin (BRL) -274, Showa Polymer Co., Ltd.) was added to 2 phr and mixed uniformly at room temperature to obtain a photosensitive siloxane polyimide resin composition. Here, the meaning of phr is the addition amount (parts by mass) when the polyimide solid content is 100 parts by mass.

Reference Example 2 (photosensitive siloxane polyimide resin composition containing no crosslinking agent)
Do not use a liquid epoxy resin (jER807, Japan Epoxy Resin Co., Ltd.), a benzoxazine (BF-BXZ, Konishi Chemical Co., Ltd.), or a resole resin (BRL-274, Showa Polymer Co., Ltd.), which is a crosslinking agent Except for the above, a siloxane polyimide resin was obtained in the same manner as in Reference Example 1, and a photosensitive siloxane polyimide resin composition was obtained.

Reference Example 3 (Creation of a wiring board physically roughened by wet blasting)
The copper surface of a copper-clad laminate (Iupicel N, Ube Nitto Kasei Co., Ltd.) with an insulation layer thickness of 25 μm and a copper thickness of 12 μm is applied to Macau's wet blast system (see http://www.macoho.co.jp/) Was subjected to surface roughening treatment under the following conditions (WB1) to obtain a physically roughened wiring board (average surface roughness Ra: 73.95 nm).

(WB1 condition)
Abrasive: Alumina fine particles Center particle size: 6.7 μm
Abrasive concentration in aqueous slurry: 14% by volume
Use gun: Wide type Processing speed: 1.8m / min Projection distance: 20mm
Projection angle: 90 degrees Air pressure: 0.15 Mpa

Reference Example 4 (Creation of a wiring board physically roughened by wet blasting)
Except for setting the air pressure to 0.25 MPa (WB2 condition), the wiring board physically roughened was obtained by repeating Reference Example 3 (average surface roughness Ra: 100.7 nm).

Reference Example 5 (Creation of chemically roughened wiring board)
For the copper surface of a copper clad laminate (Iupicel N, Ube Nitto Kasei Co., Ltd.) having an insulation layer thickness of 25 μm and a copper thickness of 12 μm, first, a 10-fold diluted solution (liquid temperature) of an acidic cleaning solution (CB-7612, MEC Co., Ltd.) 25 ° C), tap water, 4% caustic soda solution (40 ° C), pure water, pre-dip into etching solution (25 ° C) (BO7770VP, MEC), etching Dip into liquid (25 ° C) (BO7770VP, MEC Co., Ltd.), spray pure water, drain with an air knife (50 ° C), and dry with hot air (80 ° C) blower to make the copper surface chemically A wiring board roughened was obtained (etching amount: about 0.5 μm).

Reference Example 6 (Creation of chemically polished wiring board)
First, the copper surface of a copper clad laminate (Iupicel N, Ube Nitto Kasei Co., Ltd.) having an insulating layer thickness of 25 μm and a copper thickness of 12 μm is diluted 10 times with a soft etching solution (CPE-755, Mitsubishi Gas Chemical Co., Ltd.) (Solution temperature 30 ° C.), followed by 5% sulfuric acid. Then, it wash | cleaned with the pure water, drained with the air knife, and dried with the hot air (50 degreeC) blower, and obtained the wiring board by which the copper surface was chemically grind | polished.

Examples 1-6 and Comparative Examples 1-3
According to the combinations shown in Table 1, the photosensitive siloxane polyimide resin composition of Reference Example 1 or 2 was applied to the wiring boards of Reference Examples 3 to 6 so as to be 10 μm after temporary drying using a bar coater. Dry at 10 ° C. for 10 minutes. The resin composition film was exposed to ultraviolet rays (condition 2500 mJ / cm ² ) through an exposure mask. After the exposure, the substrate was immersed in a 3% by mass aqueous sodium hydroxide solution at 40 ° C. for 60 seconds to remove the exposed portion of the resin composition film and develop. The substrate was washed with water at 30 ° C. for 60 seconds, acid washed with 10% by mass of dilute sulfuric acid aqueous solution at room temperature for 10 seconds, and further washed with distilled water at room temperature for 120 seconds. Thereafter, post-baking (200 ° C., 60 minutes) was performed in a nitrogen atmosphere, the resin composition film was thermally cured, and a wiring board provided with a protective layer was obtained.

<Evaluation of inhibitory effect on bleeding out of cyclic dimethylsiloxane>
A sample having a width of 4 mm and a length of 50 mm was cut out from the location where the resin composition film was present from the wiring boards of the examples and comparative examples, and the flow was helium gas flowing at a flow rate of 50 ml / min at 260 ° C. The sample was purged of volatile components by heating for 15 minutes, while the volatile components were trapped in a Tenax-TA collection tube at -20 ° C. Subsequently, the trapped component was vaporized into a helium gas stream under predetermined conditions, and the helium gas was introduced into a GC-MS apparatus (JAS100, JAI), and the amount of cyclic dimethylsiloxane was quantified. The obtained results are shown in Table 1.

<Evaluation of plating resistance>
A gold plating film (0.03 μm thick) was formed by performing electrolytic direct gold plating on the exposed copper surface of the wiring boards of Examples and Comparative Examples. Alternatively, by performing electrolytic nickel / gold plating, hard Ni (3 μm) / gold plating (0.05 μm thickness) was formed on the exposed portion where the copper surface was exposed. The state of discoloration of the protective layer at the peripheral edge of the electrolytic plating region in the obtained wiring boards of Examples and Comparative Examples that were subjected to electrolytic plating and provided with a protective layer was visually evaluated. The case where no color change was evaluated as good (G), and the case where even a slight color change occurred was evaluated as bad (NG).

＊１： 感光性シロキサンポリイミド樹脂組成物
＊２： 配線板
＊３： 参考例２のシロキサンポリイミド樹脂組成物
＊４： 参考例１のシロキサンポリイミド樹脂組成物
＊５： 参考例６の化学的に研磨処理された配線板
＊６： 参考例３のウェットブラスト処理により物理的に粗化処理された配線板
＊７： 参考例４のウェットブラスト処理により物理的に粗化処理された配線板
＊８： 参考例５の化学的に粗化処理された配線板

* 1: Photosensitive siloxane polyimide resin composition * 2: Wiring board * 3: Siloxane polyimide resin composition of Reference Example 2 * 4: Siloxane polyimide resin composition of Reference Example 1 * 5: Chemical polishing of Reference Example 6 Treated wiring board * 6: Wiring board physically roughened by wet blasting in Reference Example * 7: Wiring board physically roughened by wet blasting in Reference Example * 8: The chemically roughened wiring board of Reference Example 5

  As is apparent from Table 1, the wiring board subjected to surface roughening treatment in Reference Examples 3 to 5 has a three-dimensional cross-linking structure made of a thermosetting product of a specific siloxane polyimide resin composition containing the cross-linking agent of Reference Example 1. It turns out that the wiring board of Examples 1-6 provided with the protective layer which has has the bleeding out of cyclic dimethylsiloxane oligomer being suppressed, and is excellent also in plating resistance.

  On the other hand, the wiring board of Comparative Example 1 provided with a protective layer obtained by using the photosensitive siloxane polyimide resin composition of Reference Example 2 containing no crosslinking agent on the conventional chemically polished wiring board of Reference Example 6 was It can be seen that the bleeding out of the cyclic dimethylsiloxane oligomer is not suppressed and there is a problem in the plating resistance. The wiring board of Comparative Example 3 provided with a protective layer obtained by using the photosensitive siloxane polyimide resin composition of Reference Example 1 is not suppressed from bleeding out of the cyclic dimethylsiloxane oligomer, and is resistant to plating. It turns out that there is still a problem. On the contrary, compared with the case of Comparative Example 1, the wiring board of Comparative Example 2 having a protective layer obtained by using the photosensitive siloxane polyimide resin composition of Reference Example 1 containing a crosslinking agent is a cyclic dimethylsiloxane oligomer. Although the bleed-out was suppressed, the plating resistance was improved as compared with Comparative Example 1, but it was found that there was a problem with the plating resistance as compared with Comparative Example 3 and Examples 1-6. .

  In the printed wiring board provided with the protective layer of the present invention, a siloxane diamine having a diphenylsilylene unit is used as a diamine component, and a protective layer such as a thin film made of a photosensitive siloxane polyimide resin composition has a specific thermosetting property. Since a three-dimensional structure is formed by the crosslinking agent, bleeding out of the cyclic dimethylsiloxane oligomer can be suppressed or prevented, and good plating resistance can be obtained by thermosetting. Furthermore, since the copper or copper alloy wiring pattern of the printed wiring board has been surface-roughened in advance, the adhesion between the copper or copper alloy wiring pattern and the protective layer can be improved, and the protective layer is resistant to plating. Sex is even better. Therefore, it is useful as a printed wiring board with high connection reliability.

Claims (12)

Photosensitive siloxane polyimide resin composition comprising a siloxane polyimide resin obtained by imidizing a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and a siloxane-free diamine, a crosslinking agent, and a photoacid generator A protective layer made of a thermosetting material is a printed wiring board formed on at least a part of a copper or copper alloy wiring pattern of the printed wiring board,
At least one selected from the group consisting of liquid epoxy resins, benzoxazines and resols is used as a crosslinking agent, 1 to 20 parts by mass with respect to 100 parts by mass of a siloxane polyimide resin, and a photoacid generator is used as a photosensitive agent. Use 5 to 30 parts by mass with respect to 100 parts by mass of siloxane polyimide resin,
A printed wiring board, wherein the surface of the copper or copper alloy wiring pattern is subjected to surface roughening.   The printed wiring board according to claim 1, wherein the crosslinking agent is a liquid epoxy resin and / or a benzoxazine, or a liquid epoxy resin, a benzoxazine and a resole.   The viscosity of the liquid epoxy resin is 1 to 100,000 mPa.s. The printed wiring board according to claim 1, which is s.   The printed wiring board according to claim 1, wherein the tetracarboxylic dianhydride is 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic dianhydride. A siloxane diamine having a diphenylsilylene unit has the formula (1)

(In the formula, n is an integer of 1 to 30, and m is an integer of 1 to 20.)
The printed wiring board in any one of Claims 1-4 which has the structure of these.   The printed wiring board according to claim 1, wherein the siloxane-free diamine is a diaminophenol derivative.   The printed wiring board according to claim 6, wherein the diaminophenol derivative is 3,3'-diamino-4,4'-dihydroxydiphenylsulfone.   A polysiloxane polyimide resin obtained by imidizing a reaction mixture of tetracarboxylic dianhydride, siloxane diamine and siloxane-free diamine in the presence of 0.01 to 1.1% by mass of water The printed wiring board according to any one of claims 1 to 7.   The printed wiring board according to claim 1, wherein the photoacid generator is an o-quinonediazide compound. It is a manufacturing method of the printed wiring board according to claim 1,
The surface of the copper or copper alloy wiring pattern on the printed wiring board is surface roughened,
A siloxane polyimide resin obtained by imidizing a tetracarboxylic dianhydride, a siloxane diamine having a diphenylsilylene unit and a siloxane-free diamine on at least a part of a copper or copper alloy wiring pattern subjected to surface roughening treatment; A printed wiring board in which a photosensitive siloxane polyimide resin composition containing a crosslinking agent and a photoacid generator is formed, exposed, developed, patterned, and thermally cured by post-baking to form a protective layer In the manufacturing method of
At least one selected from the group consisting of liquid epoxy resins, benzoxazines and resols is used as a crosslinking agent, 1 to 20 parts by mass with respect to 100 parts by mass of a siloxane polyimide resin, and a photoacid generator is used as a photosensitive agent. The manufacturing method characterized by using 5-30 mass parts with respect to 100 mass parts of siloxane polyimide resins.   The method according to claim 10, wherein the surface roughening treatment is a wet blast treatment using an aqueous slurry.   The manufacturing method according to claim 10, wherein the surface roughening treatment is a chemical polishing treatment using an etching agent.