JP2002134909A - Manufacturing method of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a printed wiring board which can form an etching resist in the interior or the interiors of a simple and reliable through hole or/and a simple and reliable nonthrough hole, and can impart favorable resist release characteristics to the interior or/and the interiors of the through hole or/and the nonthrough hole, even though the through hole or/and the nonthrough hole have a high aspect ratio of a through hole or/and a nonthrough hole. SOLUTION: The manufacturing method of a printed wiring board bores a through hole or/and a nonthrough hole in a laminate formed by providing each metal conducting layer on both surfaces of an insulative substrate, and performs metal plating of the laminate to use the laminate having the through hole or/and the nonthrough hole formed with each conducting layer. Before each photosensitive layer is formed on both surfaces of the laminate, an etching resist layer is at least formed on the conducting layer or/and the conducting layers in the through hole or/and the nonthrough hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 having a through hole or a non-through hole called a through hole or a via hole.

[0002]

2. Description of the Related Art A printed wiring board used in an electronic device or an electric device basically has a wiring formed of a conductive material such as copper on an insulating substrate. In a method of manufacturing a printed wiring board, a subtractive method is generally used in which a corrosion-resistant etching resist layer is provided on a conductive layer of a laminate in which a metal conductive layer is laminated on an insulating substrate, and the exposed conductive layer is removed by etching. It is. As a method of providing the etching resist layer, a method using a photosensitive layer of a photosensitive material such as a dry film and a liquid photoresist is generally used.

Further, with the recent trend toward downsizing and multifunctional electronic devices, the density of printed wiring boards used inside the devices and the miniaturization of circuit patterns have been promoted, and such conditions have been achieved. As means, a multilayered printed wiring board can be cited. In the multilayer printed wiring board, in order to form a multilayer structure, electrical continuity between layers is performed through pores such as through holes and non-through holes, each of which is generally called a through hole or a via hole and whose inner wall is covered with a conductor.

A method of forming a wiring pattern using a conductive material on a laminated plate having through holes and / or non-through holes (hereinafter, holes) using the above-mentioned photosensitive layer includes first providing metal conductive layers on both surfaces of a substrate. A through hole or a non-through hole up to an arbitrary layer is formed in the laminate, and a metal plating process is performed to form a conductive layer using the through holes. (Note that the substrate may have a wiring layer, a ground layer, and the like as an inner layer via an insulating layer.)
The holes are filled with the filling ink, and the excess filling ink is polished with a belt sander, baffle, jet, or the like. Furthermore, after laminating a dry film or applying a liquid photopolymer to form a photosensitive layer, the photosensitive material is irradiated with light to cause a chemical change to change the solubility in a developing solution. Photosensitive materials are classified into two types according to the type of chemical change. The light-irradiated part polymerizes and cures, making it insoluble in the developer.On the contrary, the functional group of the light-irradiated part changes to show solubility in the developer. It is a positive type. In any case, the photosensitive material remaining on the laminate after treatment with the developer and insoluble in the developer becomes a resist pattern having an etching resist property. Thereafter, a desired wiring pattern is obtained by performing etching and resist peeling (removal of the resist material and the filling resin).

[0005] A desired multilayer printed wiring board is manufactured by repeating the lamination (build-up method). The method of manufacturing such a multilayer printed wiring board is as described above. After forming a wiring pattern on the laminate having the above, an inner layer plate is prepared and subjected to a blackening treatment, a prepreg and an outer layer copper foil are sequentially stacked on the inner layer plate and pressed while heating. At this time, the inside of the hole of the inner layer plate is filled with the prepreg. Next, if necessary, a plating hole is formed, and a wiring pattern is formed on the outer layer copper foil, thereby forming a multilayer.

As described above, in the production of a multilayer printed wiring board, a step of applying a thermal shock such as a blackening treatment, a hot press, and a solder reflow treatment is required. Is applied, it is necessary that the filling ink is completely removed in the resist removing step. However, since the filling ink is filled in the holes, it is harder to remove than the resist film on the surface,
The difficulty increases as the aspect ratio of the hole increases. Also,
If a hole-filling ink with poor peeling is brought into the subsequent process,
The prepreg and the filling ink are mixed in the inside of the hole, and there is a problem that the above-mentioned thermal shock causes the filling ink to cause a state change or a chemical change, thereby causing defects such as cracks around the hole.

In the case where a dry film is used and the holes are not filled, a dry film is laminated after performing a physical or chemical surface treatment after forming the plated holes, and the diameter is larger than the diameter of the holes. Conventionally, a method of irradiating light so as to form lands and covering (tenting) with a dry film having completely exposed holes to achieve an etching resist for holes has also been adopted. However, in this method, the etching liquid may enter the hole due to misalignment of the pattern formation or poor adhesion of the dry film due to impurities, and a part of the inner wall of the hole may be melted. To avoid it,
It is necessary to perform the hole filling step or to increase the land diameter of the wiring pattern. In the latter case, there is a problem in increasing the density of the wiring pattern.

In the case where a liquid photoresist is used, a method of not filling the holes is to form an emulsified photosensitive resist on the surface of the laminate and the inner walls of the holes by an electrodeposition method (ED method). There is. According to this, the photosensitive layer can be formed substantially uniformly on the inner wall of the hole. However, when a negative photosensitive material is used, it is necessary to expose the inside of the hole, and when the aspect ratio of a small diameter hole or the like becomes high, it may be difficult to impart etching resist properties to the entire inner wall of the hole. When a positive-type photosensitive material is applied, exposure to the holes is not necessary, so there is no such problem as described above. However, in general, a positive-type liquid photoresist has a brittle coating film, and care must be taken in handling such as exposure. Low sensitivity, it is difficult to thicken the film,
There are many process problems, such as the need to control film thinning during alkali development, and there have been few cases of introduction.

[0009]

SUMMARY OF THE INVENTION According to the present invention, it is possible to easily and reliably obtain an etching resist inside a through hole and a non-through hole, and even if the through hole and the non-through hole have a high aspect ratio. An object of the present invention is to provide a method for manufacturing a printed wiring board having good resist peelability inside.

[0010]

As a result of intensive studies to solve the above problems, a substrate having a through hole and / or a non-through hole is subjected to a metal plating treatment so that the inside of the through hole and / or the non-through hole is reduced. In a method of manufacturing a printed wiring board using a laminate having a conductive layer provided on the surface of a substrate including the photosensitive layer on both sides of the laminate, at least a conductive layer in a through hole and / or a non-through hole is provided. It has been found that a method of manufacturing a printed wiring board on which an etching resist layer is formed can be used.

Further, as a method for forming an etching resist layer on the conductive layer in the through hole and / or the non-through hole, the method includes forming the etching resist layer on at least one surface of the laminate and the conductive layer in the through hole and / or the non-through hole. After forming an etching resist layer on the laminate and removing the etching resist layer other than the conductive layer in the through-holes and / or the non-through-holes, a printed wiring board is formed on at least both surfaces of the laminate by a method for manufacturing a printed wiring board. Was also achieved.

The present invention has also been achieved by a method for manufacturing a printed wiring board in which the etching resist layer is formed by an electrodeposition method.

Further, the present invention has been attained by a method for manufacturing a printed wiring board, wherein the etching resist layer is formed by electrodepositing a resin component dispersed in a non-aqueous solvent.

It is preferable that the etching resist layer in the hole obtained by the present invention basically has only a thin layer formed on the inner wall of the hole, but the etching resist is fixed by stretching the film inside the hole. It may be in a state (FIG. 5). Unlike the case of filling with filling ink, a thin-layered etching resist layer is formed on the inner surface of the hole, so that the etching resist layer in the hole is easily peeled off at the time of peeling the resist, which makes the operating conditions of the resist peeling step excessive. Eliminates the need.

Further, the etching resist layer in the hole is
No exposure treatment is required, and a reliable etching resist layer can be formed by a film (layer) adhered to the hole wall surface.

The substrate in the present invention is basically a plate simply made of an insulating base material and a process of manufacturing a multilayer printed wiring board having a wiring layer, a ground layer, and the like as an inner layer via an insulating layer. Refers to the substrate inside.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing a method for manufacturing a printed wiring board of the present invention using a liquid photoresist. In the case of manufacturing a printed wiring board having a through hole and a non-through hole, first, a through hole 8 and a non-through hole 9 were formed in a laminate 1 (FIG. 1A) in which conductive layers 3 were provided on both surfaces of a substrate 2. Thereafter (FIG. 1B), a plated conductive layer 4 is formed on the surface of the laminate 1 including the inside of the through hole 8 and the non-through hole 9 (FIG. 1).
(C)). Further, an etching resist layer 5 is provided on the surface of the laminated board including the plated through holes and the inside of the non-through holes (FIG. 1 (d)), and the laminated board surface is physically polished by a treatment such as a belt sander or buffing. By doing so, only the etching resist layer formed on the surface of the laminate is removed (FIG. 1E). Thereafter, a liquid photoresist layer is formed as the photosensitive layer 7 (FIG. 1 (f)), and a resist pattern is formed by a photopolymer according to a predetermined wiring pattern by exposure processing and development processing (FIG. 1).
(G)). Next, a printed wiring having a through-hole and a non-through-hole in which a wiring is formed by a conductive layer and a plated conductive layer on an insulating substrate by an etching process (FIG. 1 (h)) and a resist stripping process (FIG. 1 (i)). A board is manufactured.

FIG. 2 is a conceptual diagram showing a method for manufacturing a printed wiring board of the present invention using a dry film. In FIG. 2, only the through-hole is illustrated because the non-through-hole can be basically formed in the same manner as the through-hole. After the plating conductive layer 4 is formed on the laminate, an etching resist layer 5 is provided, and only the etching resist layer formed on the surface of the laminate is removed (FIG. 2A).
Laminated dry film (Fig. 2
(B)). Next, a resist pattern is formed by a dry film through an exposure process and a development process (FIG. 2).
(C)). Thereafter, the etching process (FIG. 2)
(D)) and a resist stripping process (FIG. 2 (e)) are performed to form a printed wiring board having a through hole in which wiring is formed by a conductive layer and a plated conductive layer on an insulating substrate.

The etching resist layer according to the method for manufacturing a printed wiring board of the present invention may be any one as long as it is insoluble in the alkali developing solution used and soluble in the resist stripping solution.
Further, the etching resist layer is formed by applying a resin dissolved in a solvent or a dispersion of a particulate resin by a dipping method, a roll coating method, an electrodeposition method, and the like, and then performing heat fusion (or drying). Can be formed. In particular, the electrodeposition method can be advantageously used because a good thin film having good follow-up properties and adhesion to the base material and very few defects such as pinholes can be obtained. Further, the thickness of the etching resist layer is preferably 0.5 to 5 μm, more preferably 1 to 3 μm, from the relationship between the resist properties of the film itself and the resist strippability.
The degree is preferred.

FIG. 5 is a conceptual diagram showing a state of forming an etching resist layer according to the present invention. As shown in FIG. 5, it is preferable that the etching resist layer in the hole obtained by the present invention basically has only the thin layer 5 formed on the inner wall of the hole 8 (right in FIG. 5). A state 10 in which an etching resist is stretched and fixed inside may be used (FIG. 5, left). Although depending on the physical properties of the liquid such as viscosity, it is generally difficult to penetrate the coating film as the aspect ratio increases, and the above-mentioned film is formed after drying. However, unlike the case of filling with the filling ink, the film formed is extremely thin as intended by the present invention, and it is possible to form a thin etching resist layer including the film on the inner surface of the hole. .

Specific examples of the resin used for the etching resist layer include styrene / maleic acid monoester copolymer, methacrylic acid / methacrylic acid ester copolymer, styrene / methacrylic acid / methacrylic acid ester copolymer, and acrylic resin. Acid / methacrylic acid ester copolymers, styrene / acrylic acid / methacrylic acid ester copolymers, vinyl acetate / crotonic acid copolymers, and vinyl acetate / crotonic acid / methacrylic acid ester copolymers;
Styrene, (meth) acrylate, vinyl acetate,
And a copolymer of a vinyl benzoate monomer and a carboxyl group-containing monomer such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, or a monoester of maleic anhydride and fumaric acid. The alkali solubility is controlled by the content of the carboxyl group or the average molecular weight.

When the above-mentioned resins are formed into a film by an electrodeposition method, basically, a printed circuit technology handbook-2nd edition-(edited by the Japan Printed Circuit Society, published by Nikkan Kogyo Shimbun) is published. Apply the electrodeposition coating method described.

Specific examples of the particulate resin used for the etching resist layer include, for example, an acrylic resin such as methacrylic acid and methacrylic acid ester, a vinyl acetate resin, and a copolymer of vinyl acetate with ethylene or vinyl chloride. Coalescent, polystyrene, copolymers of styrene with butadiene, methacrylic acid ester, and the like, and a particle dispersion obtained by emulsifying them with an emulsion polymerization method can be used. Furthermore, alkali solubility can be controlled by the amount of these carboxyl groups or the like introduced.

When the above-mentioned particulate resin is electrodeposited, an appropriate charge control agent is added to a dispersion of the particulate resin to convert the particles into positive or negative charged particles, and plating of the laminate is performed. The particulate resin is electrodeposited while applying an appropriate electric field to the conductive layer. Thereafter, the particulate resin electrodeposited on the laminate is thermally fused to form an etching resist layer. Here, since an electric field is applied to the charged particles in the dispersion solvent, it is necessary to use a non-aqueous insulating liquid as the dispersion solvent.

Further, by applying any of the above methods,
In a laminate having an etching resist layer formed on the surface of the laminate and on the inner wall of the through hole and the non-through hole, the etching resist layer on the surface of the laminate is removed, and the etching resist layer is formed only on the inner wall of the through hole. At this time, the etching resist layer on the surface, that is, the etching resist layer other than the etching resist layer formed inside the through-holes and the non-through-holes may be physically polished by processing such as belt sander and buffing.

The photosensitive layer according to the method for manufacturing a printed wiring board of the present invention is a resist material which can be used at least for manufacturing a printed wiring board by a subtractive method, and is generally a liquid photoresist or a dry film. Etc. are used. Further, in these photosensitive layers, there are various types such as a negative type or a positive type depending on the photosensitive region, sensitivity, and exposure method, but any of the photosensitive layers can be applied in the present invention. is there.

The laminated board having the conductive layers provided on both sides of the insulating substrate according to the method for manufacturing a printed wiring board of the present invention includes:
For example, those described in "Printed Circuit Technology Handbook-Second Edition-" (edited by The Printed Circuit Society of Japan, published by Nikkan Kogyo Shimbun) can be used. Examples of the insulating substrate include a paper substrate or a glass substrate impregnated with an epoxy resin or a phenol resin, a polyester film, a polyimide film, and the like. Examples of the material of the conductive layer include copper, silver, and aluminum. In addition, the present invention can be applied to an outer layer board at the time of manufacturing a multilayer printed wiring board having a step of forming a through hole, a laminate board having a wiring pattern layer, a ground layer, and the like via an insulating layer as an inner layer. It is.

Regarding the multilayer printed wiring board which performs interlayer connection by through holes and non-through holes according to the method of manufacturing a printed wiring board of the present invention, see "JPCA Standard, Build-up Wiring Board" (May 1998, Japan Printed Circuit Co., Ltd.). (Published by the Japan Industrial Association) and can basically deal with general through-holes, buried via-holes, blind via-holes, and the like that can be basically applied by the subtractive method.

As a method of forming a plated conductive layer according to the method of manufacturing a printed wiring board of the present invention, for example, when the plated conductive layer is made of copper, “Surface mounting technology” (June 1993)
Monthly, published by Nikkan Kogyo Shimbun), an electroless plating-electroless plating step, a direct electrolytic plating step, and the like can be used.

In the method for producing a printed wiring board according to the present invention, the developing solution for eluting and removing the photosensitive layer in the non-wiring portion contains a basic compound. Examples of the basic compound include inorganic basic compounds such as alkali metal silicates, alkali metal hydroxides, phosphoric acid and alkali metal carbonates and ammonium salts, alkanolamines such as ethanolamine, and alkylamines such as diethylamine and ethylenediamine. And organic basic compounds such as alkylenediamines, triethylenetetramine, and morpholine. The above basic compounds can be used alone or as a mixture. In addition, water can be advantageously used as a solvent for the eluate. Generally, an aqueous solution of sodium carbonate containing an antifoaming agent or the like is applied.

In the method of manufacturing a printed wiring board of the present invention, as a method of removing the conductive layer and the plated conductive layer of the non-wiring portion after forming a resist pattern, see "Printed Circuit Technology Handbook-Second Edition-""Printed Circuit Handbook-3rd Edition-" (1991, CF Coombs,
Jr. Eds., Edited by the Japan Printed Circuit Society, published by Modern Science Co., Ltd.).

In the method for manufacturing a printed wiring board according to the present invention, the resist pattern in the wiring portion is removed after the etching step by treating with a solution more alkaline than the developing solution used in the developing process (resist stripping process). can do. If necessary, 2-butanone, 1,4
-An organic solvent such as dioxane, methanol, ethanol, 2-propanol and 1-butanol may be added, or the organic solvent may be used alone.

[0034]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 Formation of Through Hole A double-sided copper-clad laminate (manufactured by Mitsubishi Gas Chemical Co., Ltd., 200 × 30) in which copper foil was bonded to both sides of a glass base epoxy resin plate.
After opening 100 through-holes of 0.3 mmφ and 0.5 mmφ at 0 × 0.8 mm and copper thickness of 18 μm, respectively, electroless copper plating-electrolytic copper plating (Okuno Pharmaceutical Co., Ltd., OP
C process M) was performed, and a copper plating layer having a thickness of 8 μm was provided on the surface of the laminate including the inside of the through hole.

Formation of etching resist layer and laminate
Removal of the etching resist layer on the surface In order to make it easy to see the presence or absence of the resist on the surface of the laminate and the inner wall of the through-hole, using a coating solution of Table 1 colored with carbon black by an immersion method,
After drying for minutes, an etching resist layer (thickness: 3 μm) was obtained on the surface of the laminated plate having the through holes and on the inner walls of the through holes. Further, a belt sander (belt roughness: # 100
Using 0), the etching resist layer on the surface was substantially uniformly removed, and a water washing treatment was performed.

[0037]

[Table 1]

Formation and registration of liquid photoresist layer
DOO patterning Next, a liquid a negative type photoresist to laminate to form an etching resist layer on the inner wall of the through hole (Taiyo Ink
Co., Ltd., "PER-20") was applied using a roll coater and dried. In this state, as shown in FIG. 1 (f), a portion that is not applied was conspicuous in the inner wall of the through hole. Next, after performing exposure processing, development processing was performed using a 2.0% aqueous sodium carbonate solution (liquid temperature 35 ° C.).
A resist pattern corresponding to a desired wiring pattern was formed as shown in FIG.

Etching and resist stripping treatment Further, the laminate having the resist pattern formed thereon was treated with a ferric chloride solution (40 ° C., spray pressure: 3.0 kg / cm ² ) to remove portions not covered with the resist pattern. The copper plating layer and the copper layer were removed. Then, at 40 ° C.
Treatment with a 0% sodium hydroxide solution was performed to remove the remaining etching resist layer to obtain a printed wiring board. When the obtained printed wiring board was observed with a microscope, no defects such as disconnection were found in the wiring pattern, and no defects such as pinholes and cracks were found on all the inner walls of the through holes. No resist residue was found inside the through-holes of any diameter.

Example 2 Formation of a non-through hole A double-sided copper-clad laminate (manufactured by Mitsubishi Gas Chemical Co., Ltd., 200 × 30) in which copper foils were adhered to both sides of a glass base epoxy resin plate.
A nickel layer was formed on the double-sided copper layer (0 × 0.8 mm, copper thickness 18 μm) by electroless nickel plating. A negative type liquid photoresist (manufactured by Taiyo Ink Mfg. Co., Ltd., "PER-20") was applied on the nickel layers on both sides using a roll coater and dried. Next, an exposure process was performed through a photomask having an arbitrary wiring pattern on the front surface, and the entire back surface was exposed. Thereafter, development processing is performed using a 2.0% aqueous solution of sodium carbonate (solution temperature: 35 ° C.) to remove the photosensitive layer in the non-wiring portion, and further, a ferric chloride solution (40 ° C., spray pressure: 3) 2.0 kg / cm ² ) to remove the copper layer and the nickel layer in the non-wiring portion, and then treat with a 4.0% sodium hydroxide solution at 40 ° C. to remove the remaining photosensitive layer. A copper wiring pattern was formed on one surface of the conductive substrate.

An insulating photosensitive resin solution having the composition shown in Table 2 was applied to the surface of the single-sided printed wiring board where the wiring was obtained by a curtain coating method, and dried to form an insulating photosensitive resin layer (45 μm thick). Formed. Next, the insulating photosensitive resin layer is exposed to light through a mask having a desired pattern of non-through holes, and then developed with 1,1,1-trichloroethane at 15 ° C. 200 through holes were produced. Thereafter, the film was treated at 120 ° C. for 20 minutes to thermally cure the insulating photosensitive resin layer, thereby completely extinguishing the photosensitivity. Then, 40 g of chromic anhydride, 200 g of concentrated sulfuric acid, 800 pure
The surface of the insulative photosensitive resin layer was roughened in order to improve the adhesiveness of the copper plating layer formed by the subsequent copper plating treatment by a treatment with hydrochloric acid or the like. In the above operation, although the copper layer at the bottom of the non-through hole was protected by the nickel layer, the nickel layer was removed with a nickel etching solution (manufactured by Meltex Corporation).
Thereafter, an electroless copper plating-electrolytic copper plating treatment (Okuno Pharmaceutical Co., Ltd., OPC process M) was performed to form an 18 μm copper plating layer in the insulating photosensitive resin layer on the surface of the substrate and in the non-through holes.

[0042]

[Table 2]

Formation of etching resist layer and laminate
Removal of the etching resist layer on the surface Table 1 colored with carbon black to make it easy to see the presence or absence of the resist on the surface of the laminate and the inner wall of the non-through hole
After coating by the dipping method using a coating solution of
After drying for 0 minute, an etching resist layer (thickness: 3 μm) is formed on the surface of the laminate having the non-through holes and inside the non-through holes
I got Further, a belt sander (belt roughness: # 10
Using (00), the etching resist layer on the surface was substantially uniformly removed and subjected to a water washing treatment.

Formation and registration of liquid photoresist layer
DOO patterning Next, non-penetrating holes inside the etching resist layer formed was laminated plate negative type liquid photoresist (Taiyo Ink Mfg.
Co., Ltd., "PER-20") was applied using a roll coater and dried. In this state, as shown in FIG. 1 (f), a portion that is not applied is conspicuous in the inner part of the non-through hole. Next, after performing exposure processing, development processing was performed using a 2.0% aqueous sodium carbonate solution (liquid temperature 35 ° C.).
A resist pattern corresponding to a desired wiring pattern was formed as shown in FIG. Etching and resist stripping treatment Further, the laminate having the resist pattern formed thereon is treated with a ferric chloride solution (40 ° C., spray pressure: 3.0 kg / cm ² ), and the copper plating layer not covered with the resist pattern And the copper layer was removed. Then, at 40 ° C.
Treatment with a 0% sodium hydroxide solution was performed to remove the remaining etching resist layer to obtain a printed wiring board. When the obtained printed wiring board was observed with a microscope, no defects such as disconnection were found in the wiring pattern, and no defects such as pinholes and cracks were found inside all the non-through holes. No resist residue was found inside all the non-through holes.

Example 3 A method for producing a printed wiring board of the present invention was attempted by a method in which an etching resist layer was formed by an electrodeposition method (ED method) using a resin dissolved in a solvent. First, a laminate having a through hole formed by a plated conductive layer as in Example 1 was prepared. Next, using an electrodeposition solution colored with carbon black shown in Table 3, it was applied by an electrodeposition method (applied current: 100 mA), dried at 120 ° C. for 20 minutes, and etched on the surface of the laminate and the inner wall of the through hole. Layer (surface thickness 2.
5 μm). Further, the etching resist layer on the surface was substantially uniformly removed using a belt sander (belt roughness: # 1000), and a water washing treatment was performed.

[0046]

[Table 3]

Thereafter, after forming a liquid photoresist in the same manner as in Example 1, exposure processing is performed, and development processing is performed using a 2.0% sodium carbonate aqueous solution (liquid temperature 35 ° C.), and FIG. As described above, a resist pattern corresponding to a desired wiring pattern was formed. Further, an etching treatment and a resist peeling treatment (a treatment at 40 ° C. with a 3.0% sodium hydroxide solution) were performed to obtain a printed wiring board having through holes.
When the obtained printed wiring board was observed with a microscope, no defects such as disconnection were found in the wiring pattern, and no defects such as pinholes and cracks were found on all the inner walls of the through holes. No resist residue was found inside the through-holes of any diameter.

Example 4 The method for producing a printed wiring board of the present invention was attempted by a method in which an etching resist layer was formed by electrodeposition using a dispersion of particulate resin. First, a laminate having a through hole formed by a plated conductive layer as in Example 1 was prepared. Next, the colored emulsion fine particle-dispersed toner shown in Table 4 was electrodeposited (applied voltage: 180 V), and then left at 120 ° C. for 10 minutes to be heat-fused. (A surface film thickness of 1.2 μm).
Furthermore, using a belt sander (belt roughness: # 1000), the etching resist layer on the surface is substantially uniformly removed,
A water washing treatment was performed.

[0049]

[Table 4]

Then, after forming a liquid photoresist in the same manner as in Example 1, exposure processing is performed, and development processing is performed using a 2.0% aqueous solution of sodium carbonate (liquid temperature 35 ° C.). As described above, a resist pattern corresponding to a desired wiring pattern was formed. Further, an etching treatment and a resist peeling treatment (a treatment at 40 ° C. with a 3.0% sodium hydroxide solution) were performed to obtain a printed wiring board having through holes.
When the obtained printed wiring board was observed with a microscope, no defects such as disconnection were found in the wiring pattern, and no defects such as pinholes and cracks were found on all the inner walls of the through holes. No resist residue was found inside the through-holes of any diameter.

Example 5 Next, a tenting method using a dry film was performed to manufacture a printed wiring board of the present invention. As in Example 1, a 50 μm-thick dry film was laminated on a laminate (FIG. 2A) having an etching resist layer formed on the inner wall of the through-hole, subjected to appropriate exposure treatment, and subjected to a 2.0% aqueous sodium carbonate solution ( A developing process was performed using a liquid temperature of 35 ° C.) to form a resist pattern (FIG. 2C). However, at this point, as shown in the right through-hole in FIG. 2C, some of the through-holes were found to be in an incompletely tented state due to a shift in the exposure position.

In this state, an etching process and a resist stripping process were performed in the same manner as in Example 1. In the through hole where the tenting was incomplete, as shown in FIG. Even so, the copper plating layer on the inner wall of the through hole was resisted. Except for this, no pinholes or cracks were observed in all the through holes, and no resist residue was observed in any of the through holes.

Comparative Example 1 An attempt was made to manufacture a general printed wiring board using a liquid photoresist by applying a hole filling method. First, a laminate having a plated through hole was produced in the same manner as in Example 1. Next, after filling the inside of the through-holes with a hole filling ink (SER-450W, manufactured by San-ei Chemical Co., Ltd.) by a roll coating method, it was thermally cured. Filling ink on the copper plating layer other than inside the through-hole was removed by buffing and washing (FIG. 3).
(A)). Then, a liquid photoresist layer was formed (FIG. 3 (b)) and a resist pattern was formed (FIG. 3 (c)) in the same manner as in Example 1. As can be seen from the through hole on the right side of FIG. 3 (c), a state in which the resist near the edge of the through hole was incomplete due to the displacement of the exposure position was confirmed.

In this state, an etching process (FIG. 3D) and a resist stripping process were performed under the same conditions as in Example 1 (FIG. 3E). As shown in FIG. 3 (e), the copper plating layer on the inner wall of the through-hole was resisted even in a part where the resist was not resisted. Except for this, no pinholes or crevices were observed in all the through holes. However, in the resist stripping treatment under the same conditions, a resist residue was confirmed in many through holes, and particularly in a 0.3 mmφ through hole having a high aspect ratio, a resist residue was confirmed in almost all through holes.

Comparative Example 2 A general printed wiring board was manufactured by a tenting method using a dry film. First, a laminate having a plated through hole was produced in the same manner as in Example 1 (FIG. 4).
(A)). A dry film having a thickness of 50 μm was laminated thereon (FIG. 4B), and subjected to an appropriate exposure treatment.
A developing process was performed using a 0% aqueous sodium carbonate solution (solution temperature 35 ° C.) to form a resist pattern (FIG. 4).
(C)). However, at this point, some of the through holes are
As shown in the through hole on the right side of (c), the state where the tenting of the through hole was incomplete due to the displacement of the exposure position was confirmed.

In this state, an etching process (FIG. 4D) and a resist stripping process were performed under the same conditions as in Example 1 (FIG. 4E). The plated copper layer on the inner wall of the through hole was also well resisted.
As shown in (e), the etching resist could not be performed, and the copper plating layer on the inner wall of the through hole was completely removed. In this case, since no resist is formed inside the through-hole, no resist residue is naturally confirmed.

[0057]

As described above, according to the method of manufacturing a printed wiring board of the present invention, a thin etching resist layer is formed inside a through hole and / or a non-through hole prior to forming a resist pattern, so that the method is simple and easy. The resist inside the through-hole and / or the non-through-hole is surely achieved, and even if the through-hole and / or the non-through-hole have a high aspect ratio, there is an excellent effect that the inside has a good resist peeling property.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a method for manufacturing a printed wiring board of the present invention using a liquid photoresist.

FIG. 2 is a conceptual diagram showing a method for manufacturing a printed wiring board of the present invention using a dry film.

FIG. 3 is a conceptual diagram showing a method for manufacturing a general printed wiring board using a liquid photoresist.

FIG. 4 is a conceptual diagram showing a method for manufacturing a general printed wiring board using a dry film.

FIG. 5 is a conceptual diagram showing a state of forming an etching resist layer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated board 2 Substrate 3 Conductive layer 4 Plating conductive layer 5 Etching resist layer 6 Filling ink 7 Photosensitive layer 8 Through hole 9 Non-through hole 10 Resist film 11 Resist residue

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/40 521 G03F 7/40 521 H05K 3/06 H05K 3/06 EF Term (Reference) 2H025 AA03 AA16 AB15 AC01 AD01 AD03 DA29 DA40 EA01 EA08 FA01 2H096 AA26 CA01 CA05 CA16 DA10 EA02 5E317 AA24 BB01 BB11 CC31 CD25 CD27 CD32 GG16 5E339 AB02 AD03 AE01 BD02 BD03 BD08 BD11 BE11 CC01 CD01 CE05 CE12 CE19 CF16 CF17 DD

Claims (4)

[Claims] 1. A printed wiring board using a laminate in which a conductive layer is provided on a substrate including a through hole and / or a non-through hole by performing a metal plating process on the substrate having the through hole and / or the non-through hole. The method according to claim 1, wherein prior to forming the photosensitive layers on both sides of the laminate, an etching resist layer is formed on at least the conductive layer in the through-holes and / or the non-through-holes. Manufacturing method. 2. An etching resist layer is formed on at least one surface of a laminate and on a conductive layer in a through hole and / or a non-through hole, and an etching resist other than on the conductive layer in the through hole and / or the non-through hole is provided. The method according to claim 1, wherein a photosensitive layer is formed on at least both sides of the laminate after removing the layer. 3. The method for manufacturing a printed wiring board according to claim 1, wherein said etching resist layer is formed by an electrodeposition method. 4. The method for manufacturing a printed wiring board according to claim 1, wherein the etching resist layer is formed by electrodepositing a resin component dispersed in a non-aqueous solvent.