JP2010180355A - Thermosetting resin composition, dry film, printed wiring board and preparation thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosetting resin composition for obtaining a resin insulation layer having an appropriate desmear property, a dry film using the same, a printed wiring board, and its preparation. <P>SOLUTION: The thermosetting resin composition for laser processing contains a phenol resin, an epoxy resin, and an inorganic filler. It has a hydroxy group/epoxy group (equivalent ratio) of 0.3 to 1.0. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermosetting resin composition, a dry film and a printed wiring board using the same, and a method for producing the same.

  In general, when mounting electronic components on a printed wiring board used in electronic devices, it is possible to prevent solder from adhering to unnecessary portions and expose circuit conductors to be oxidized or oxidized. In order to prevent corrosion due to humidity, a solder resist layer is formed in a region excluding connection holes on the substrate on which the circuit pattern is formed.

  Usually, when forming a soldering resist pattern on a board | substrate using a thermosetting resin composition, the via hole for mounting is formed by irradiation of a laser beam. In particular, when a fine solder resist pattern is required, a carbon dioxide gas laser, a UV-YAG laser, an excimer laser, or the like is used.

  In such via hole formation by laser light, a component (smear) of the solder resist film is not decomposed and removed, and a phenomenon of remaining at the bottom of the via hole occurs. If such smears remain, defects such as unplated portions occur in the subsequent plating process, and poor bonding occurs when electronic components are mounted. For this reason, a so-called desmear process for removing the smear is required.

  In such a desmear process, a wet method is generally used in which a smear is decomposed and removed by a permanganate solution after swelling with a concentrated alkaline solution.

  However, if the desmear is surely carried out by such a method, there arises another problem that the surface of the solder resist layer is roughened or the solder resist layer is peeled off by these chemical solutions. On the other hand, when trying to suppress this roughening phenomenon or peeling phenomenon, there is a problem that smear cannot be removed reliably (desmearing property is reduced).

  On the other hand, conventionally, a method has been proposed in which a layer that is easily desmeared is formed on the solder resist layer (first layer) on the substrate side that remains as smear, and a layer that is difficult to be desmeared is formed on the surface layer (second layer) ( For example, see Patent Document 1).

  However, since it is a resin insulating layer having a two-layer structure, there is a problem that process costs increase.

JP 2004-240233 A (paragraph 0008 and the like)

  As described above, a resin insulating layer for laser processing using a thermosetting resin composition is required to satisfy both desmearing resistance and desmear resistance.

  Accordingly, an object of the present invention is to provide a thermosetting resin composition capable of obtaining a resin insulation layer capable of satisfying both desmearability and desmear resistance, a dry film using the same, a printed wiring board, and a method for producing the same. There is to do.

  As a result of earnest research toward the realization of the above object, the inventors have completed an invention having the following contents.

  That is, the thermosetting resin composition for laser processing of the present invention contains a phenol resin, an epoxy resin, and an inorganic filler, and has a hydroxyl group / epoxy group (equivalent ratio) of 0.3 to 1.0. It is characterized by this.

  With such a configuration in which the hydroxyl group / epoxy group (equivalent ratio) is specified, it is possible to obtain a resin insulation layer having an appropriate desmear property capable of achieving both desmear property and desmear resistance.

  In the thermosetting resin composition of the present invention, the epoxy resin is preferably a mixture of an epoxy resin that is liquid at 20 ° C. and an epoxy resin that is solid at 40 ° C.

  As described above, by using an epoxy resin composed of a mixture of an epoxy resin that is liquid at 20 ° C. and a solid epoxy resin that is solid at 40 ° C., a resin insulating layer that has a suitable film property with moderate desmear properties is obtained. It becomes possible. As a result, it is suitably used for dry film resist applications.

  Moreover, it is preferable that the dry film of this invention is equipped with the application | coating drying film | membrane of the above thermosetting resin compositions.

  With such a configuration, it is possible to easily form a resin insulating layer having an appropriate desmear property capable of achieving both desmear property and desmear resistance on the substrate.

  Further, the printed wiring board of the present invention includes a substrate on which circuit wiring is formed, a resin insulating layer formed on at least a part of the substrate and formed from the above-described thermosetting resin composition, and the resin insulation. It is preferable to provide a via hole that penetrates the layer and reaches the circuit wiring.

  Further, in the printed wiring board of the present invention, a substrate on which circuit wiring is formed, a resin insulating layer formed on at least a part of the substrate and formed from the above-described dry film, and penetrating through the resin insulating layer Preferably, a via hole formed to reach the circuit wiring is provided.

  With such a configuration, the surface of the resin insulation layer is prevented from being roughened, and sufficient electrical continuity is obtained at the connection part of the electronic component, making it possible to stably and easily obtain a highly reliable printed wiring board. It becomes.

  Also, the method for producing a printed wiring board of the present invention applies the above-mentioned thermosetting resin composition onto a substrate on which circuit wiring is formed, and dries and cures the applied thermosetting resin composition. It is preferable to form an insulating layer, irradiate a predetermined position of the resin insulating layer with a laser to form a via hole reaching the circuit wiring, and then perform a desmear treatment.

  Further, in the method for producing a printed wiring board of the present invention, the above-mentioned dry film is pressure-bonded onto a substrate on which circuit wiring is formed, and the resin-insulated layer is formed by curing the pressure-bonded dry film, and this resin insulation It is preferable to perform a desmear treatment after forming a via hole reaching a circuit wiring by irradiating a laser at a predetermined position of the layer.

  With such a configuration, the surface of the resin insulation layer can be prevented from being roughened, and sufficient electrical continuity can be obtained at the connection part of the electronic component, making it possible to stably and easily manufacture a highly reliable printed wiring board. It becomes.

  According to the thermosetting resin composition of the present invention and a dry film using the same, it is possible to obtain a resin insulating layer for laser processing having an appropriate desmear property capable of achieving both desmear property and desmear resistance.

  Further, according to the printed wiring board and the manufacturing method thereof of the present invention, the surface of the resin insulating layer is prevented from being roughened, and sufficient conduction is obtained at the connection part of the electronic component, so that the printed wiring board is highly reliable. Can be obtained stably.

It is a schematic side view which shows the two test tubes used for the liquid determination of the epoxy resin.

  Hereinafter, embodiments of the present invention will be described.

  The thermosetting resin composition for laser processing of the present invention contains a phenol resin, an epoxy resin, and an inorganic filler, and has a hydroxyl group / epoxy group (equivalent ratio) of 0.3 to 1.0. It is a feature.

  In particular, in order to obtain good film properties, it is preferable to use a mixture of an epoxy resin that is liquid at 20 ° C. and a solid epoxy resin that is solid at 40 ° C. as the epoxy resin. The blending ratio is preferably 20 to 80% by mass, more preferably 40 to 60% by mass of a liquid epoxy resin at 20 ° C. in the total amount of epoxy resin. This is because if it is less than 20% by mass, it becomes difficult to form a film, while if it exceeds 80% by mass, the surface of the insulating layer is likely to be roughened.

  Here, the “liquid” determination method referred to in this specification will be described.

  Judgment of liquid state shall be made in accordance with the second “Liquid Confirmation Method” of the Ministerial Ordinance on Dangerous Goods Testing and Properties (Ministry of Local Government Ordinance No. 1 of 1989).

(1) Apparatus Constant-temperature water bath: A device equipped with a stirrer, a heater, a thermometer, and an automatic temperature controller (with temperature control at ± 0.1 ° C.) having a depth of 150 mm or more.

  In the determination of the epoxy resin used in the examples to be described later, a combination of a low temperature thermostatic water tank (model BU300) manufactured by Yamato Scientific Co., Ltd. and a thermostat (model BF500) of the input type thermostatic apparatus (model BF500) is used. Put 22 liters in a low temperature constant temperature water bath (model BU300), turn on the thermomate (model BF500) assembled to it and set it to the set temperature (20 ° C or 40 ° C), and set the water temperature to the set temperature ± 0.1 Although fine adjustment was performed with a thermomate (model BF500) at 0 ° C., any apparatus capable of the same adjustment can be used.

Test tube:
As shown in FIG. 1, the test tube is made of a flat bottom cylindrical transparent glass having an inner diameter of 30 mm and a height of 120 mm, and marked lines 11 and 12 are respectively provided at heights of 55 mm and 85 mm from the tube bottom. The test tube 10a for liquid judgment with the mouth of the test tube sealed with a rubber plug 13a, and a rubber plug 13b having the same size and the same marked line, and a hole for inserting and supporting a thermometer in the center A test tube 10b for temperature measurement in which the mouth of the test tube is sealed and a thermometer 14 is inserted into the rubber plug 13b is used. Hereinafter, a marked line having a height of 55 mm from the tube bottom is referred to as “A line”, and a marked line having a height of 85 mm from the tube bottom is referred to as “B line”.

  As the thermometer 14, the one for freezing point measurement (SOP-58 scale range 20-50 ° C.) specified in JIS B7410 (1982) “Petroleum test glass thermometer” is used, but the temperature is 0-50 ° C. It is sufficient if the range can be measured.

(2) Test procedure The sample that was allowed to stand for 24 hours or more at an atmospheric pressure of 20 ± 5 ° C. was used for the liquid determination test tube 10a shown in FIG. 1 (a) and the temperature measurement test shown in FIG. 1 (b). Insert up to line A in each tube 10b. Two test tubes 10a and 10b are left standing in a low-temperature thermostatic water tank so that the line B is below the water surface. The thermometer has its lower end 30 mm below the A line.

  The state is maintained as it is for 10 minutes after the sample temperature reaches the set temperature ± 0.1 ° C. After 10 minutes, remove the liquid judgment test tube 10a from the low-temperature water bath, immediately lay it down horizontally on a horizontal test bench, and use the stopwatch to measure the time the tip of the liquid level in the test tube has moved from line A to line B. Measure and record. A sample is determined to be liquid if the measured time is within 90 seconds at a set temperature, and solid if it exceeds 90 seconds.

  In the present invention, examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, and phenol novolac type epoxy resin. Cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like are used. And these epoxy resins can be used individually or in combination of 2 or more types.

  Here, as an epoxy resin that is liquid at 20 ° C., for example, 828 (made by Japan Epoxy Resin), YD-128 (made by Toto Kasei), 840, 850 (made by DIC), bisphenol A type epoxy resins, 806, 807 (manufactured by Japan Epoxy Resin), YDF-170 (manufactured by Tohto Kasei), 830, 835, N-730A (manufactured by DIC), ZX-1059 (manufactured by Toto Kasei) Bisphenol A, F mixture such as YX-8000, 8034 (manufactured by Japan Epoxy Resin Co., Ltd.) ST-3000 (manufactured by Toto Kasei Co., Ltd.), and the like.

  Moreover, as an epoxy resin solid at 40 ° C., for example, Epicron 1050, 3050 (manufactured by DIC), Epicoat 1001, 1002, 1003 (manufactured by Japan Epoxy Resin), Epototo YD-011, Bisphenol A type epoxy resin such as YD-012 (manufactured by Toto Kasei), bisphenol F type epoxy resin such as Epototo YDF-2001, 2004 (manufactured by Toto Kasei), YDB-400 (manufactured by Toto Kasei) , Brominated bisphenol A type epoxy resins such as EPICLON152 and 153 (manufactured by DIC), bisphenol S type epoxy resins such as EXA-1514 (manufactured by DIC), N-770,775 (manufactured by DIC), EPPN-201H, RE- Phenol novolac epoxy resins such as 306 (Nippon Kayaku Co., Ltd.), 152, 154 (Japan Epoxy Resin Co., Ltd.), EOCN-102S, 103S, 104S (Nippon Kayaku Co., Ltd.) Cresol novolac type epoxy resin such as YDCN-701, 702, 703, 704 (manufactured by Toto Kasei), N-660, 670, 680 (manufactured by DIC), 157S70 (manufactured by Japan Epoxy Resin), N-865 (DIC) Bisphenol A novolak type epoxy resin such as YX-4000 (made by Japan Epoxy Resin), biphenyl type epoxy resin such as NC-3000 (made by Nippon Kayaku), NC-7000L (made by Nippon Kayaku), etc. Naphthalene type epoxy resin, HP-7200 (manufactured by DIC), XD-1000 (manufactured by Nippon Kayaku Co., Ltd.) and other dicyclopentadiene type epoxy resins, EPPN-501H, 502H (manufactured by Nippon Kayaku Co., Ltd.), 1031S (Japan) And triphenylmethane type epoxy resins such as epoxy resin).

  Specific examples of the phenol resin in the present invention include Phenolite TD-2090, 2131, Besmol CZ-256-A (manufactured by Dainippon Ink & Chemicals, Inc.), Siolanol BRG-555, BRG-556 ( As mentioned above, Showa Polymer Co., Ltd.), Millex XLC-4L, XLC-LL (Mitsui Chemicals), PP-700, 1000, DPP-M, 3H, DPA-145, 155 (above, Shin Nippon Petrochemical Co., Ltd.), SK-resin HE100C, SK-resin HE510, and 900 (manufactured by Sumikin Chemical Co., Ltd.). These phenol resins can be used alone or in combination of two or more.

  Such a phenol resin needs to be blended in such a ratio that the hydroxyl group / epoxy group (equivalent ratio) is 0.3 to 1.0. When the hydroxyl group / epoxy group (equivalent ratio) deviates from this range, the surface of the resin insulating layer is roughened in the desmear process.

As the inorganic filler in the present invention, for example, barium sulfate, calcium sulfate, silica, clay, talc, aluminum hydroxide and the like can be used. These have an absorption peak in the range of wave number 900-1300cm ^-1 which is the wavelength band of carbon dioxide laser in the infrared absorption spectrum by FT-IR, and sublimate or decompose at the time of laser processing, thus suppressing residues after laser processing can do.

  Among these inorganic fillers, barium sulfate and calcium sulfate are exemplified as those having a strong absorption peak particularly in the above-mentioned laser wavelength band and capable of suppressing inorganic filler residues during the formation of via holes. Of these, barium sulfate is more preferable from the viewpoint of residue control. In addition, mica, alumina, titanium oxide, other metal oxides, metal hydroxides such as aluminum hydroxide, and the like can also be used. And these inorganic fillers can be used individually or in combination of 2 or more types.

  The average particle diameter of such an inorganic filler is preferably 5 μm or less, and the blending amount is desirably 20 to 100% by mass with respect to the solid content of the composition. When the blending amount of the inorganic filler is less than 20% by mass, the film performance such as the hardness of the cured film is insufficient, and the laser processability is not good. On the other hand, if it exceeds 100% by mass, interfacial peeling occurs with the resin, which may cause cracks. In addition, coating properties such as leveling properties are deteriorated, and the shape of the via hole becomes unstable by degreasing from the side surface and the periphery of the via hole in a desmear process after laser processing. More preferably, it is 30-50 mass%.

  The thermosetting resin composition of the present embodiment may further contain a phenoxy resin, a curing catalyst, an additive, a solvent, and the like.

  The phenoxy resin can be blended in order to improve the film forming property. For example, 1256, 4250, 4275, YX8100BH30, YX6954BH30 (manufactured by Japan Epoxy Resin Co., Ltd.), YP50, YP50S, YP55U, YP70, ZX-1356-2, FX-316, YPB-43C, ERF-001M30, YPS-007A30, FX-293AM40 (manufactured by Tohto Kasei Co., Ltd.) and the like. These phenoxy resins can be used alone or in combination of two or more.

  As the curing catalyst, dicyandiamide, aromatic amine, imidazoles, acid anhydrides and the like can be used. Specifically, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2- Imidazole derivatives such as cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, 4 -Amine compounds such as methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine, and other commercially available products include, for example, Shikoku Kasei Kogyo Co., Ltd. 2MZ made A, 2MZ-OK, 2PHZ, 2P4MHZ (all are trade names of imidazole compounds), U-CAT3503N, U-CAT3502T (all are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U -CATSA102 and U-CAT5002 (both are bicyclic amidine compounds and salts thereof). These curing catalysts can be used alone or in combination of two or more.

  Guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as -S-triazine / isocyanuric acid adducts and 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adducts can also be used, and these also function as adhesion promoters. The compound to be used is preferably used in combination with a thermosetting catalyst.

  Examples of additives include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, naphthalene black and the like, which are known and commonly used colorants (any of pigments, dyes, and pigments), An antifoaming agent, a rheology adjusting agent, etc. can be used.

  As the solvent, ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents and the like can be used. More specifically, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl Glycol ethers such as ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate , Propylene glycol butyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, etc. Esters; ethanol, propanol, ethylene glycol, alcohols such as propylene glycol; octane, aliphatic hydrocarbons decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and petroleum solvents such as solvent naphtha. These solvents can be used alone or in combination of two or more.

  Such a solvent can be made into the compounding quantity suitable for the printability of a composition, and film formability.

  Such a thermosetting resin composition of this embodiment can be made into the dry film which apply | coated on the carrier film, dried and wound up as a film.

  Next, the manufacturing method of the printed wiring board using the thermosetting resin composition or dry film of this embodiment is demonstrated.

  First, after pre-treatment such as degreasing and soft etching is performed on the circuit-formed substrate, the thermosetting resin composition adjusted with an organic solvent to a viscosity suitable for the coating method is 10 to 50 μm in dry film thickness. Apply as follows. Next, a tack-free coating film (resin layer) is formed by volatile drying (temporary drying) of the organic solvent contained in the composition at a temperature of 40 to 100 ° C.

  Here, as a coating method, methods such as a dip coating method, a flow coating method, a roll coating method, a bar coater method, a screen printing method, and a curtain coating method can be used.

  As a volatile drying method, a method using a hot air circulating drying furnace, an IR furnace, a hot plate, a convection oven, or the like equipped with a heat source of an air heating method using steam, and a method in which the hot air in the dryer is brought into countercurrent contact and a nozzle A method of spraying on a support can be used.

  In this step, a coating film (resin layer) can also be formed by laminating a dry film prepared using the thermosetting resin composition of the present invention on a substrate.

  Next, the substrate on which the coating film (resin layer) has been formed is heated at 150 to 180 ° C. for 30 to 120 minutes and thermally cured to form a resin insulating layer.

  Next, the resin insulating layer thus formed is irradiated with a laser at a position corresponding to a predetermined position on the circuit-formed substrate to form a via hole, and the circuit wiring is exposed. At this time, there is a component (smear) that cannot be removed and remains on the circuit wiring in the via hole.

  Then, a desmear process is performed in which the smear is decomposed and removed using a desmear chemical such as a permanganate solution to produce a printed wiring board.

  Note that, in a double-sided board and a multilayer board, a cured film is similarly formed using a thermosetting resin composition, and a via hole is formed by laser, followed by desmear treatment.

  After the printed wiring board manufactured in this way is subjected to gold plating on the circuit wiring or preflux treatment, electronic components such as semiconductor chips to be mounted are mounted by bonding with gold bumps or solder bumps. .

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

(Preparation of thermosetting resin composition)
Each component shown in Table 1 was blended, premixed with a stirrer, and then kneaded using a three-roll mill to prepare thermosetting resin compositions of Examples 1 to 5 and Comparative Examples 1 to 7.

* 1: Bisphenol A type epoxy resin (Japan Epoxy Resin)
* 2: Varnish (manufactured by Nippon Kayaku Co., Ltd.) in which trihydroxyphenylmethane type epoxy resin is dissolved in propylene glycol monomethyl ether acetate so that the nonvolatile content is 80%.
* 3: Phenoxy resin (Japan Epoxy Resin)
* 4: 1-benzyl-2-phenylimidazole (manufactured by Shikoku Chemicals)
* 5: Varnish (Maywa Kasei Co., Ltd.) in which phenol novolac resin is dissolved in diethylene glycol monoethyl ether to a non-volatile content of 65%.
(Preparation of sample for evaluation)
The thermosetting resin compositions of Examples 1 to 5 and Comparative Examples 1 to 7 thus prepared were applied to a polyethylene terephthalate film having a thickness of 38 μm using an applicator so that the film thickness after drying was 30 μm. And it was made to dry at 40-100 degreeC, and the dry film for evaluation of Examples 1-5 and Comparative Examples 1-7 was produced.

  Then, each dry film was subjected to chemical polishing treatment with a circuit formed under the conditions of 0.8 MPa, 110 ° C., 1 minute, 133.3 Pa using a vacuum laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.). The board | substrate for evaluation of Examples 1-5 and Comparative Examples 1-7 was produced by carrying out heat lamination to the board | substrate, and heat-hardening at 170 degreeC for 1 hour.

(Performance evaluation)
(Film test)
About the dry film for evaluation of Examples 1-5 and Comparative Examples 1-7, it bent 90 degree | times and evaluated the flexibility of the film on the following references | standards.

◯: There was no abnormality such as cracks in the resin part. Δ: Some cracks occurred. X: Cracks occurred in the resin part. As is apparent from the results shown in Table 1, in Examples 1 to 5, no abnormality such as a crack was observed in the resin part, but in Comparative Examples 1 to 4 and Comparative Example 7, cracks occurred.

(Desmear resistance test)
For the substrates for evaluation of Examples 1 to 5 and Comparative Examples 1 to 7, Circoposit MLB conditioner 211 (Rohm and Haas, organic solvent containing additives) and Circoposit Z (Rohm and Haas, sodium hydroxide) In a mixture of distilled water and distilled water at 60 to 80 ° C. for 3 to 10 minutes, Circoposit MLB promoter 213A (Rohm and Haas, manufactured by sodium permanganate as a main component) And circuposit MLB promoter 213B (manufactured by Rohm and Haas, solution containing sodium hydroxide as a main component) and distilled water for 3 to 15 minutes at 65 to 85 ° C. to decompose the swollen smear. Removed.

  Furthermore, it was immersed in a mixed solution of Circoposit MLB Neutralizer 216-2 (manufactured by Rohm and Haas, a solution containing sulfuric acid as a main component) and distilled water at 43 to 51 ° C. for 5 to 7 minutes for neutralization treatment.

  After these treatments, the surface state of the cured coating film was observed visually and by SEM (scanning electron microscope), and evaluated according to the following criteria.

○: No change is observed at all Δ: Slight change is observed ×: The coating film is roughened or peeled Evaluation results are shown in Table 1. As is clear from the results shown in Table 1, in Examples 1-5, no change was observed, but in Comparative Examples 4, 5, a slight change was observed, and Comparative Examples 1-3, 6 In, it was found that the coating film was roughened or peeled off.

  In addition, this invention is not limited to embodiment mentioned above. Various other modifications can be made without departing from the scope of the invention.

10a ... Test tube for liquid judgment 10b ... Test tube for temperature measurement 11 ... Mark (A line)
12 ... Mark line (B line)
13a, 13b ... rubber stopper 14 ... thermometer

Claims (7)

Contains phenolic resin, epoxy resin, and inorganic filler,
A thermosetting resin composition for laser processing, wherein hydroxyl group / epoxy group (equivalent ratio) is 0.3 to 1.0.   The thermosetting resin composition according to claim 1, wherein the epoxy resin is a mixture of an epoxy resin that is liquid at 20 ° C and an epoxy resin that is solid at 40 ° C.   A dry film comprising a coating and drying film of the thermosetting resin composition according to claim 1. A substrate on which circuit wiring is formed;
A resin insulation layer formed on at least a part of the substrate and cured from the thermosetting resin composition according to claim 1 or 2,
A printed wiring board comprising a via hole penetrating through the resin insulating layer and reaching the circuit wiring. A substrate on which circuit wiring is formed;
A resin insulating layer formed on at least a part of the substrate and cured from the dry film according to claim 3,
A printed wiring board comprising a via hole penetrating through the resin insulating layer and reaching the circuit wiring. The thermosetting resin composition according to claim 1 or 2 is applied on a substrate on which circuit wiring is formed,
The applied thermosetting resin composition is dried and cured to form a resin insulating layer,
A method for manufacturing a printed wiring board, comprising: forming a via hole reaching a circuit wiring by irradiating a predetermined position of the resin insulating layer with a laser, and then performing a desmear process. The dry film according to claim 3 is pressure-bonded onto a substrate on which circuit wiring is formed,
Curing the dry-bonded dry film to form a resin insulation layer;
A method for manufacturing a printed wiring board, comprising: forming a via hole reaching a circuit wiring by irradiating a predetermined position of the resin insulating layer with a laser, and then performing a desmear process.

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