JPH1041610A - Manufacture of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of hardening hindrance due to oxygen by applying liquid resist and then pasting a transparent film through a pressure sensitive adhesive, and then exposing and developing and finally forming a resist plating layer. SOLUTION: Liquid resist is so applied as to cover a conductor circuit formed on the surface of a substrate and the resist is dried to form a resist layer. Next, a polyethylene terephthalate(PET) film 8 which has a pressure sensitive adhesive layer formed on its one face is pasted and pressurized to be adhered tightly. After that, a photo mask film 7 is placed and ultraviolet rays are cast to expose the substrate. Then, the PET film 8 and the photo mask film 7 are removed and the resist layer is dissolved to form a resist layer for plating with a conductor circuit pattern removed, on the substrate in the development process. After that, the substrate is exposed and heat-treated to form a solder resist layer 91 on an interlayer insulating layer. Since the liquid resist is applied and dried and then the transparent film is pasted with the pressure sensitive adhesive airtightly on the surface of the dried resist, air does not enter the substrate, and thereby a generation of hardening hindrance due to oxygen can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for manufacturing a printed wiring board which is excellent in the precision of forming a plating resist and a solder resist and whose film thickness is not reduced by a developing process.

[0002]

2. Description of the Related Art In an additive wiring board, an adhesive layer for electroless plating is formed, and this is roughened to form fine irregularities on the surface, a plating resist is formed thereon, and then electroless plating is performed. To form a conductor circuit. According to the Polymer Handbook (published on June 26, 1989, Photopolymer Handbook Society), a resist in which a photosensitive dry film is adhered on a PET film as a base film is disclosed as a resist. . Further, it is disclosed that a photosensitive dry film is also preferable for a solder resist. However, these statements
This can be said in the subtractive method, which is currently the mainstream of printed wiring boards, and in the additive method, steps formed by a roughened surface or a plating resist and a conductor circuit,
Alternatively, liquid resist is more preferable than dry film in consideration of the followability to the depression due to the via hole.

[0003]

However, in the case of a liquid resist, there has been a problem that the film thickness becomes smaller than the coating amount when exposure and development are performed. As a result of extensive studies by the present inventors, the cause of this is
It has been found that the liquid resist comes into contact with oxygen in the air to cause curing inhibition and is insufficiently cured, so that the liquid resist is dissolved by the developer. In the case of a dry film, in order to prevent such a trouble due to oxygen, it is possible to perform exposure while leaving a PET film as a base film as it is (the above-mentioned “Polymer Handbook” P288). Does not have such a base film, and when a liquid resist is applied, its surface is not completely flat,
Even if the ET film is loaded, air enters, and anyway, curing inhibition occurs. An object of the present invention is to prevent the inhibition of hardening due to oxygen in forming a plating resist and a solder resist by applying a liquid resist.

[0004]

According to the present invention, in order to prevent curing inhibition by oxygen, a light-transmitting film is adhered through an adhesive to block oxygen to prevent curing inhibition. is there. That is, `` form an adhesive layer for electroless plating on a substrate, roughen the surface, apply a photosensitive liquid resist, form a plating resist by exposure and development, and then perform electroless plating. A method of manufacturing a printed wiring board for forming a conductive circuit, comprising: applying a liquid resist, applying a light-transmitting film via an adhesive, and then exposing and developing to form a plating resist. Wiring board manufacturing method ",

[0005] In a method of manufacturing a printed wiring board, a photosensitive liquid resist is applied to the surface of a conductive pad formed on a substrate, and an opening is provided by exposure and development to form a solder resist. After that, a method of manufacturing a printed wiring board, comprising: attaching a light-transmitting film via an adhesive, and then exposing and developing to form a solder resist ”,

[0006] The printed wiring according to claim 2, wherein the conductive pad is formed by roughening an adhesive layer for electroless plating, forming a plating resist thereon, and providing the plating resist in a portion where the plating resist is not formed. Board ",

The method for manufacturing a printed wiring board according to any one of claims 1 to 3, wherein the translucent film has a thickness of 1 to 20 μm.

[0008] The method for producing a printed wiring board according to any one of claims 1 to 3, wherein the translucent film is a thermoplastic resin film.

The method according to any one of claims 1 to 3, wherein the translucent film is a polyethylene terephthalate film.

In the present invention, the liquid resist is applied and dried, and the light-transmitting film is adhered to the surface by the adhesive, so that air does not enter and as a result, the inhibition of curing by oxygen is prevented. For this reason, the thickness of the plating resist or the solder resist does not decrease even after the development. In addition, when a photomask is directly placed on a liquid resist for forming a plating resist or a solder resist, slippage is poor and the alignment of the photomask is difficult due to the adhesiveness of the resist itself. Since the functional film is adhered, the photomask is slippery, which facilitates the alignment of the photomask, and there is no shift in the formation positions of via holes and patterns.

Further, in the case of a liquid resist, although the surface is not completely flat, an adhesive is interposed between the light transmitting film and the resist surface, so that the adhesion between the resist and the light transmitting film is reduced. Do not let. The translucent film is 1 to
A thickness of 20 μm is desirable. This is because the thinner the film is, the easier it is to break, and the thicker the film is, the lower the resolution of the liquid resist is. Desirably, 5 to 16 μm, more preferably 8 to 12 μm
It is. Further, the translucent film has a temperature of 40 to 60 ° C,
It is applied to a liquid resist dried by heating and pressing at a pressure of 1 to 10 kg / cm ² .

The adhesive includes natural rubber, styrene-butadiene, polyisobutylene, isoprene, acrylic, acrylic emulsion, silicone, natural rubber latex, and styrene-butadiene latex. Specifically, it is described in "Notes on Adhesive Utilization by the Industrial Research Council", edited by Ken Ihouchi, Koei Komatsu and Yasuaki Kitazaki. As natural rubber, natural rubber 1
100 to 100 parts by weight, tackifying resin 150 to 120 parts by weight, zinc white 25 to 50 parts by weight, calcium carbonate 35 to
Examples thereof include those comprising 60 parts by weight, 15 parts by weight of carbon black, an antioxidant, and sulfur. Styrene butadiene (SBR) includes SBR 100 parts by weight, zinc white 5 parts by weight, titanium oxide 10 parts by weight, yellow pigment 0.3
Examples include those comprising 12 parts by weight of an oil-soluble phenol resin, 40 parts by weight of an ester gum, 25 parts by weight of paraffin oil, and 40 parts by weight of a chromanindine resin.
As polyisobutylene-based, polyisobutylene 100
And 10 parts by weight of polybutene and 20 parts by weight of white oil. Examples of polyisoprene-based materials include Kuraray IR-10, Kuraray JSR2200, and Nippon Zeon Nippol 2200.
And the like. Acrylics include acrylic acid 2
-Ethylhexine 78 parts by weight, methyl acrylate 20 parts by weight, maleic anhydride 2 parts by weight, hexamethylenediamine 0.5 parts by weight. As the silicone type, 100 parts by weight of silicone rubber, 80 to 120 parts by weight of silicone resin, 0.01 to 0.5 of condensation catalyst
100 parts by weight of a solvent and 100 to 150 parts by weight of the solvent. Examples of the acrylic emulsion system include those comprising 70 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of vinyl acetate, and 2 parts by weight of acrylic acid. Examples of the natural rubber-latex system include 182 parts by weight of an organic peroxide prevulcanized natural rubber latex, 250 parts by weight of hydrogenated rosin ester, and 4 parts by weight of an antioxidant dispersion. As the styrene-butadiene system, 100 parts by weight of rubber latex, 89 parts by weight of a high melting point tackifier, 5.6 parts by weight of a soap-forming resin acid,
Examples include 4.8 parts by weight of an antioxidant, 0.7 parts by weight of ammonia water, and 151 parts by weight of water.

As the translucent film, a thermoplastic resin film is desirable. This is because they have excellent flexibility and followability when heated. Specifically, polyethylene terephthalate (PET), polyvinyl alcohol (PVA),
Examples include polyethylene (PE). Particularly, polyethylene terephthalate is desirable. Since the PET film has excellent heat resistance and little thermal expansion and contraction due to heating and cooling, the film hardly expands and contracts even when heat cured after exposure. The liquid resist used in the present invention will be described. The same applies to both plating resists and solder resists.

As the liquid resist, a plating resist composition comprising a novolak type epoxy resin acrylate and an imidazole curing agent is preferable. This is because the plating resist needs to have basic resistance. Novolak type epoxy resins include phenol novolak type and cresol novolak type.

In the present invention, the plating resist composition desirably contains a bisphenol type epoxy resin and a photosensitive monomer. Bisphenol type epoxy resin can improve base resistance and flexibility,
The photosensitive monomer improves the resolution. The bisphenol-type epoxy resin includes a bisphenol A-type epoxy resin and a bisphenol F-type epoxy resin. In the case, the latter is better.

In the present invention, an imidazole curing agent can be used. This is because an epoxy resin cured with an imidazole curing agent has excellent heat resistance and chemical resistance, and has excellent properties with respect to a base. The addition amount of the imidazole curing agent is 1
-10% by weight is desirable. The reason for this is that uniform mixing is easy in this range. When used as a solder resist, a coloring matter such as phthalocyanine green or various pigments may be added in order to secure hiding properties.

Next, the method for manufacturing a printed wiring board of the present invention will be described in detail. (1) The substrate used in the present invention is formed by etching a copper-clad laminate into a copper pattern, or forming an adhesive layer for electroless plating on a glass epoxy substrate, a polyimide substrate, a ceramic substrate, a metal substrate, or the like. And make an opening in this,
This can be roughened to form a roughened surface, which is then subjected to electroless plating to form a copper pattern and a via hole. Through holes are formed in the core substrate to electrically connect the wiring layers on the front surface and the back surface.

(2) Next, an adhesive layer for electroless plating is formed on the substrate. As the adhesive for electroless plating, an adhesive obtained by dispersing cured heat-resistant resin particles soluble in an acid or an oxidizing agent in an uncured heat-resistant resin hardly soluble in an acid or an oxidizing agent is most suitable. . this is,
This is because by roughening and removing the heat-resistant resin particles soluble in the acid or the oxidizing agent, an octopus-shaped anchor can be formed on the surface and the adhesion to the conductor circuit can be improved.

As the heat-resistant resin hardly soluble in an acid or an oxidizing agent, a photosensitive thermosetting resin or a composite of a photosensitized thermosetting resin and a thermoplastic resin is preferable. By sensitizing, via holes can be easily formed by exposure and development. Further, by forming a composite with a thermoplastic resin, the toughness can be improved, the peel strength of the conductor circuit can be improved, and the occurrence of cracks in the via holes due to the heat cycle can be prevented.

Specifically, epoxy acrylate obtained by reacting an epoxy resin with acrylic acid or methacrylic acid, or a composite of epoxy acrylate and polyether sulfone is preferred. Epoxy acrylate has two of all epoxy groups.
It is desirable that 0 to 80% react with acrylic acid or methacrylic acid.

Further, as the heat resistant resin particles,
Heat-resistant resin powder having an average particle size of 10 μm or less, aggregated particles obtained by aggregating a heat-resistant resin powder having an average particle size of 2 μm or less,
A mixture of a heat-resistant powder resin powder having an average particle size of 10 μm or less and a heat-resistant resin powder having an average particle size of 2 μm or less, on the surface of the heat-resistant resin powder having an average particle size of 2 μm to 10 μm,
It is desirable to select from pseudo particles obtained by adhering at least one of a heat-resistant resin powder and an inorganic powder having an average particle diameter of 2 μm or less. These are because they can form complex anchors.

As the heat resistant resin particles, epoxy resin, amino resin (melamine resin, urea resin, guanamine resin) and the like are preferable. The solubility of the epoxy resin in an acid or an oxidizing agent can be arbitrarily changed by changing the type of the oligomer, the type of the curing agent, and the crosslink density. For example, a bisphenol A-type epoxy resin oligomer cured with an amine-based curing agent is easily dissolved in an oxidizing agent. However, the novolak epoxy resin oligomer cured with an imidazole-based curing agent is hardly dissolved in the oxidizing agent. The adhesive layer for electroless plating does not need to be a single layer, for example, the lower layer is an insulating layer,
It may have a two-layer structure in which the surface is further provided with an adhesive layer for electroless plating.

The lower layer of the interlayer insulating agent has an average particle size of 0.1.
An adhesive for electroless plating having a heat-resistant resin powder of 1 to 0.3 μm or less, and an upper layer of a heat-resistant resin powder having an average particle diameter of 10 μm or less and a heat-resistant resin powder having an average particle diameter of 2 μm or less. It is also possible to form a two-layer structure as an electroless plating adhesive having a mixture.

The acid used in the present invention includes phosphoric acid, hydrochloric acid, sulfuric acid, or organic acids such as formic acid and acetic acid. Organic acids are particularly preferable. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded.
The oxidizing agent is preferably chromic acid or permanganate (such as potassium permanganate). In particular, in the case of dissolving and removing the amino resin, it is preferable to perform a roughening treatment alternately with an acid and an oxidizing agent.

(3) After drying the adhesive for electroless plating, if it is a photosensitive resin, it is exposed and developed, and if it is a thermosetting resin, it is heated and cured to form an opening for a via hole with a laser. Provide.

(4) After roughening the surface, a catalyst nucleus is provided. The catalyst nucleus is preferably a noble metal ion or a colloid, and generally uses palladium chloride or a palladium colloid. It is desirable to perform a heat treatment to fix the catalyst core. The catalyst core is preferably palladium.

(5) Next, a plating resist is formed.
As the plating resist, after applying and drying the above-described liquid resist, a light-transmitting film to which the adhesive is adhered is attached so that the surface of the adhesive is in contact with the liquid resist side. Conversely, an adhesive may be applied to the resist surface and a translucent film may be attached. Next, a temperature of 40 to 60 ° C. and a pressure of 1
The resist is brought into close contact with the dried resist by heating and pressing at a pressure of 10 to 10 kg / cm ² . Next, it is formed by exposing and developing by irradiating ultraviolet rays.

(6) Primary plating is performed on the surface of the plating resist and the surface of the adhesive for electroless plating. Further, not only a copper pattern but also a via hole is formed. As the primary plating, it is necessary to use at least two kinds of metal ions selected from copper, nickel, cobalt, and phosphorus. This is because these alloys have high strength and improve peel strength. Because it can be. In the primary electroless plating solution, it is necessary to use at least two or more types of metal ions selected from copper, nickel and cobalt. This is because these alloys have high strength and improve peel strength. Because you can do it. Also, a hydroxycarboxylic acid is required because it acts as a complexing agent and forms a stable complex with copper, nickel and cobalt ions under basic conditions.

This electroless plating solution requires a reducing agent, but this is for reducing metal ions to metal elements. The reducing agent is preferably hypophosphite. This is because nickel can be precipitated.

The pH adjuster used in the present invention is at least one selected from sodium hydroxide, potassium hydroxide and calcium hydroxide, and is a basic compound.
This is because hydroxycarboxylic acid forms a complex with nickel ions and the like under basic conditions.

The reducing agent is desirably at least one selected from aldehydes, hypophosphites (referred to as phosphinates), borohydrides, and hydrazines. This is because these reducing agents are water-soluble and have excellent reducing power. As the hydroxycarboxylic acid, citric acid, malic acid, tartaric acid and the like are desirable. They are,
This is because it is easy to form a complex with nickel, cobalt, and copper. The concentration of the hydroxycarboxylic acid is 0.1 to 0.8M
It is desirable that If the amount is less than 0.1 M, a sufficient complex cannot be formed, resulting in abnormal precipitation or decomposition of the liquid. 0.
If it exceeds 8 M, problems such as a low deposition rate and an increase in generation of hydrogen occur.

The electroless plating solution desirably contains bipyridyl. The reason for this is that bipyridyl can suppress the generation of metal oxides in the plating bath and the generation of nodules. Copper ions, nickel ions, and cobalt ions are supplied by dissolving copper, nickel, and cobalt compounds such as copper sulfate, nickel sulfate, cobalt sulfate, copper chloride, nickel chloride, and cobalt chloride.

The primary plating film formed by the plating solution of the present invention has excellent followability to the roughened surface of the adhesive layer for electroless plating, and traces the form of the roughened surface as it is. Therefore, the primary plating film has an anchor like the roughened surface. Therefore, the anchor of the secondary plating film formed on the primary plating film is secured by the anchor. Since the primary plating film controls the peel strength, a plating film deposited by the plating solution of the present invention having high strength is desirable, and the secondary plating film has high electric conductivity,
Since a high deposition rate is desirable, simple copper plating is more desirable than composite plating.

(7) The secondary plating film is a copper plating film. The secondary plating film is desirably formed by dipping in the next electroless plating solution. In an electroless plating solution comprising copper ions, trialkanolamine, a reducing agent and a pH adjuster, the concentration of copper ions is 0.005 to 0.5.
015 mol / l, the concentration of the pH adjuster is 0.25 to
0.35 mol / l, and the concentration of the reducing agent is 0.01 to
An electroless plating solution having a concentration of 0.04 mol / l. This is because the plating solution has a stable bath and generates little nodules and the like. The secondary electroless plating solution is
Desirably, the concentration of trialkanolamine is 0.1 to 0.8M. This is because the plating precipitation reaction most easily proceeds in this range.

The trialkanolamine is desirably at least one selected from the group consisting of triethanolamine, triisopananolamine, trimethanolamine and tripropanolamine. Because it is water-soluble.
The reducing agent used in the secondary electroless plating solution is desirably at least one selected from aldehyde, hypophosphite, borohydride, and hydrazine. This is because it is water-soluble and has a reducing power under basic conditions. Also,
The pH adjuster is desirably at least one selected from sodium hydroxide, potassium hydroxide, and calcium hydroxide. Thus, a conductor pattern including the primary plating film and the secondary plating film is formed.

(8) The surface of the conductor circuit is subjected to a blackening reduction treatment or a needle-like plating made of Cu-Ni-P to form a roughened layer.

(9) Further, an interlayer insulating material layer is formed.
The interlayer insulating material layer can use the above-mentioned adhesive for electroless plating, and may be formed of two or more layers as described above. The formation of the conductor circuit and the plating resist formed on the interlayer insulating material layer is the same as that described above.

(10) On the surface of the printed wiring board thus formed, the surface of the adhesive for electroless plating is roughened, a plating resist is formed on the roughened surface, and the plating resist is not formed. It has a structure in which a conductor circuit is provided on the surface.

The exposed conductor circuit is covered and protected with a solder resist. In the conductor circuit, a portion on which electronic components are mounted (so-called pad) is coated with solder.
For the solder coating, a solder resist is provided in order to prevent solder from flowing and causing a short circuit between the conductor circuits. As the solder resist, the above-mentioned liquid resist is applied by a roll coater and dried, and then a light-transmitting film to which an adhesive is attached is attached so that the surface of the adhesive is in contact with the liquid resist. Conversely, a translucent film may be attached by applying an adhesive to the resist surface. next,
The resist is brought into close contact with the dried resist by heating and pressing at a temperature of 40 to 60 ° C. and a pressure of 1 to 10 kg / cm ² . Next, a solder resist having an opening is formed by irradiating and developing with ultraviolet rays.

(11) Among the formed conductor patterns,
The portions (pads) where the solder is to be formed are plated with nickel-gold.

(12) Transferring to the pad portion by a solder transfer method (a method of forming a solder pattern on a film, heating the solder pattern while contacting the pad and transferring the solder to the pad), a screen printing method, or the like. I do. Hereinafter, description will be made based on embodiments. It goes without saying that the present invention is not limited to this embodiment.

[0042]

【Example】

(1) Starting from a copper-clad laminate in which 18 μm copper foil is laminated on both sides of a substrate made of glass epoxy or BT (bismaleimide triazine) having a thickness of 1 mm, and forming the copper foil in a pattern according to a conventional method. The inner layer copper pattern 21 is formed on both surfaces of the substrate 1 by etching (FIG. 1).

(2) After the substrate is washed with water and dried, the substrate is acid-degreased and soft-etched, treated with a catalyst solution comprising palladium chloride and an organic acid, and a Pd catalyst is applied to activate the substrate. Then, plating is carried out in an electroless plating bath, and Ni-P-
An uneven layer (roughened surface) of a Cu alloy having a thickness of 2.5 μm was formed. Then, the substrate is rinsed with water, and the substrate is immersed in an electroless tin plating bath composed of a tin borofluoride-thiourea solution at 50 ° C. for 1 hour to form a substrate having a thickness of 0.1 mm on the roughened surface of the Ni—Cu—P alloy.
A 3 μm tin-substituted plating layer was formed.

(3) Here, a cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd .: molecular weight 2500) dissolved in DMDG (dimethyl glycol dimethyl ether)
70 parts by weight of 5% acrylate, 30 parts by weight of polyether sulfone (PES), 4 parts by weight of an imidazole curing agent (trade name: 2E4MZ-CN, manufactured by Shikoku Chemicals), and caprolactone-modified tris (acryloxyethyl) as a photosensitive monomer 10 parts by weight of isocyanurate (trade name: Aronix M325, manufactured by Toa Gosei), 5 parts by weight of benzophenone (manufactured by Kanto Chemical) as a photoinitiator, 0.5 part by weight of Michler's ketone (manufactured by Kanto Chemical) as a photosensitizer, and further The average particle size of the epoxy resin particles was 5.5 μm to 3
5 parts by weight and 5 parts by weight having an average particle size of 0.5 μm are mixed, further mixed while adding NMP, adjusted to a viscosity of 2000 cps with a homodisper stirrer, and then kneaded with a three-roll mill to expose the mixture. Adhesive solvent (interlayer resin insulation material)
Get 32.

(4) As the insulating material, a 25% acrylate of cresol novolak epoxy resin (manufactured by Nippon Kayaku)
70% by weight, polyether sulfone (manufactured by Mitsui Toatsu) 25
Wt%, benzophenone 4 wt%, Michler's ketone 0.
After mixing 4% by weight and an imidazole-based curing agent, the viscosity was adjusted to 30 Pa · s with a homodisper stirrer while adding normal methylpyrrolidone (NMP).
The insulating material 31 was kneaded with this roll. This is applied and dried, and then the above-mentioned photosensitive adhesive is applied to form two layers of an insulating material 31 and an adhesive layer 32 (FIG. 2).

(6) Next, a photomask film is laminated and exposed by irradiating ultraviolet rays of 400 mJ / cm ² . (7) The substrate is spray-developed with a DMTG solution to form an opening 4 serving as a 100 μmφ via hole in the adhesive layer (FIG. 3). Further, the substrate is exposed to an ultra-high pressure mercury lamp at 3000 mJ / cm ² and heat-treated at 100 ° C. for 1 hour and then at 150 ° C. for 5 hours, so that an opening having excellent dimensional accuracy equivalent to a photomask film is obtained. (Opening for forming a via hole) 50 μm thick
Is formed. Note that the tin plating layer is partially exposed in the opening 4 serving as a via hole.

(8) The substrate in which the openings 4 are formed is immersed in chromic acid for 2 minutes to dissolve the epoxy resin particles in the resin interlayer insulating layer and roughen the surface of the resin interlayer insulating layer. After being immersed in a neutralizing solution (manufactured by Shipley Co.), it is washed with water (FIG. 4). (9) By applying a palladium catalyst (manufactured by Atotech) to the substrate subjected to the surface roughening treatment (roughening depth: 20 μm), a catalyst nucleus is formed on the resin interlayer insulating layer and the opening for the via hole.

(10) On the other hand, 40
Weight-% cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.), a photosensitizing oligomer obtained by acrylated 50% of epoxy groups (molecular weight: 4000), 20% by weight bisphenol A type epoxy resin dissolved in methyl ethyl ketone (oilification) Shell Epicoat 1001), imidazole hardener (Shikoku Chemicals: 2P4MZ), photosensitive isocyanate acrylic isocyanate (Toagosei: Aronix M215), benzophenone as photoinitiator (Kanto Chemical), Michler's ketone (manufactured by Kanto Kagaku) as a photosensitizer was mixed with the following composition using NMP, and the viscosity was 3000 cps with a homodisper stirrer.
And then kneaded with three rolls to form a liquid resist 6
0 was obtained. Resin composition; photosensitive epoxy / E1001 /
BP / MK / imidazole = 70/30/10/5 /
0.5 / 5

(11) The liquid resist 60 is applied to both surfaces of the substrate 20 after the above-described treatment for providing catalyst nuclei by using a roll coater, and dried at 60 ° C. for 30 minutes to obtain a 30 μm-thick resist layer. Is formed (FIG. 5). (12) Next, an adhesive prepared by mixing 78 parts by weight of 2-ethylhexyne acrylate, 20 parts by weight of methyl acrylate, 2 parts by weight of maleic anhydride, and 0.5 part by weight of hexamethylene diamine was applied to one surface. A 12 μm-thick PET film 8 having a 2 μm-thick pressure-sensitive adhesive layer formed thereon was adhered thereto and adhered by pressing at 50 ° C. and 4 kg / cm ² (FIG. 13). Next, the photomask film 7 is placed and irradiated with ultraviolet rays of 400 mJ / cm ² (FIG. 6).

(13) The PET film and the photomask film are removed, and the resist layer is dissolved and developed with DMTG to form a plating resist on the substrate where the conductor circuit pattern is removed.
/ Cm ² , exposure at 100 ° C. for 1 hour,
A heat treatment is performed at 0 ° C. for 3 hours to form a permanent resist 61 on the interlayer insulating layer (FIG. 7). (14) The substrate on which the above-mentioned permanent resist 61 is formed is subjected to pre-plating treatment (specifically, sulfuric acid treatment or the like and activation of catalyst nuclei), and then the resist is formed by electroless plating in an electroless copper plating bath. Electroless copper plating having a thickness of about 15 μm is deposited on the non-formed portion, and the outer layer copper pattern 22,
By forming the via holes 22, a conductor layer was formed by the additive method (FIG. 8).

(15) The conductor layer formed by the additive method is polished on one side with a belt sander using # 600 belt abrasive paper. At this time, polishing is performed until the surface layer of the permanent resist is aligned with the uppermost surface of copper in the via hole. After that, buffing is performed to remove the scratches caused by the belt sander (only buffing may be performed). Then, the other surface is similarly polished to form a flat printed circuit board on both surfaces. Then, the conductor layer 23 is further formed by the additive method by repeating the above-described steps. By building up the wiring layers in this way, a six-layer multilayer printed wiring board is formed (FIG. 9).

(16) A liquid resist 90 is applied so as to cover the conductor circuit on the surface. This liquid resist 90
Is obtained by mixing phthalocyanine green with the product prepared in (10) and coloring the mixture. After application, 3 at 60 ° C
Drying is performed for 0 minute to form a 30 μm-thick resist layer 90 (FIG. 10). Next, the same pressure-sensitive adhesive as that of (12) was applied to one side to form a pressure-sensitive adhesive layer having a thickness of 2 μm and a thickness of 12 μm.
m PET film 8 at 50 ° C, 4kg / c
Pressure was applied at m ² for close contact. Then, the photomask film 7 is placed and irradiated with 400 mJ / cm ² of ultraviolet light.
Exposure (FIG. 11).

The PET film 8 and the photomask film 7 were removed, and the resist layer was dissolved and developed with DMTG to form a plating resist on the substrate where the conductor circuit pattern was removed.
exposed with cm ^2, 1 hour, then at 100 ° C, 0.99
A heat treatment is performed at 3 ° C. for 3 hours to form a solder resist 91 on the interlayer insulating layer (FIG. 12). (17) Nickel-gold plating is performed according to a conventional method.

(Comparative Example 1) Basically the same as in Example, except that a liquid resist was applied and dried before forming a plating resist and a solder resist, and then a PET film was not applied.

(Comparative Example 2) Basically the same as in the Example, but a so-called dry film type resist prepared by spreading a resist composition thinly on a PET film with a squeegee or the like was used instead of a liquid resist. With respect to the wiring boards manufactured in Examples and Comparative Examples, the followability of the plating resist with the roughened surface and the followability of the solder resist with the surface steps and via holes were examined. Further, the film thickness was reduced by the development, and the displacement of the photomask was examined.

Regarding the followability of the plating resist,
A cycle test was performed 1000 times at 65 to 125 ° C.
Among the pieces, the number of pieces that were peeled off from the roughened surface was examined. Regarding the followability of the solder resist, it was confirmed by an optical microscope whether or not the solder resist was buried in the via hole on the surface, and the number of pieces that were not buried was examined. The reduction in film thickness due to development was measured by an optical microscope before and after development. Regarding the positional deviation of the photomask, the amount of positional deviation between via holes formed in the lower inner layer pad and the interlayer insulating material was observed with an optical microscope.

[0057]

[Table 1]

[0058]

As described above, according to the present invention, even if the liquid resist follows the roughened surface or the via hole,
The light-transmitting film can be closely attached, so that there is no reduction in film thickness or displacement of the photomask film due to inhibition of curing by oxygen. Therefore, a highly reliable wiring board can be manufactured.

[Brief description of the drawings]

FIG. 1

FIG. 12 is a schematic view of the manufacturing process of the present invention.

FIG. 13 is a schematic diagram showing a bonding state of a liquid resist layer, an adhesive layer, and a PET film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 21 Conductor circuit of 1st layer 31 Insulating material layer 32 Photosensitive adhesive (interlayer resin insulating material) 4 Hole for via hole 5 Roughened surface 60 Liquid resist layer (for plating resist) 61 Plating resist 7 Pit mask film Reference Signs List 8 PET film 90 Liquid resist layer 91 Solder resist (for plating resist) 10 Adhesive layer

Claims (6)

[Claims] 1. An electroless plating adhesive layer is formed on a substrate, the surface is roughened, a photosensitive liquid resist is applied, a plating resist is formed by exposure and development, and then electroless plating is performed. A method of manufacturing a printed wiring board for forming a conductive circuit by applying a liquid resist, pasting a light-transmitting film via an adhesive, and then exposing and developing to form a plating resist. To manufacture printed wiring boards. 2. A method for manufacturing a printed wiring board, comprising forming a solder resist by applying a photosensitive liquid resist on a surface of a conductive pad formed on a substrate and providing an opening by exposure and development. A method for manufacturing a printed wiring board, comprising: applying a translucent film via an adhesive after application, and exposing and developing to form a solder resist. 3. The print according to claim 2, wherein the conductive pad is formed by roughening an adhesive layer for electroless plating, forming a plating resist thereon, and providing the plating resist in a portion where the plating resist is not formed. Wiring board. 4. The method for manufacturing a printed wiring board according to claim 1, wherein said light-transmitting film has a thickness of 1 to 20 μm. 5. The method according to claim 1, wherein the translucent film is a thermoplastic resin film. 6. The method according to claim 1, wherein the light-transmitting film is a polyethylene terephthalate film.