JPH0936519A - Manufacture of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring intermediate material with which the conductive circuit of a high density printed wiring board is simply formed without generating a defect on the inner wall of a conductive hole even when there is positional deviation on a master film, and also requiring a long process. SOLUTION: A printed wiring board intermediate material is formed as follows. A through hole is formed in a copper-clad laminated board, a liquid etching resist is applied to the copper-clad laminated board in which a conducting hole is formed on the front and the backside by electroless and electrolytic plating or electroless plating, the resist is dried up and a photosensitive resin film is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the printed wiring board processing industry, an intermediate material necessary for forming a conductive pattern by forming an etching resist image on a copper-clad laminate by a photographic method and removing unnecessary metal parts by etching. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, there are an additive method and a subtractive method as a method for forming a conductor pattern on a printed wiring board. Among them, the materials used for the subtractive method are described below. Is filled with a resin that can be dissolved in an organic solvent or an aqueous alkaline solution such as an aqueous solution of sodium hydroxide, and an etching resist ink is drawn by a screen printing method to draw a circuit pattern on the etching resist ink. There is a method of forming a conductor pattern by drying and etching unnecessary metal.

Further, there is a method of drawing an etching resist pattern using a photographic method in order to draw a fine pattern as compared with the screen printing method, but it is currently most widely used. This photographic method will be described in detail. A copper-clad laminate provided with a conductive hole is coated with a film of a resin composition containing a photosensitive resin as a main component on the front and back surfaces to form a film at the opening of the conductive hole, and then the etching solution is used. There is a tenting method that protects the inner wall of the conduction hole.Activities such as ultraviolet rays are transmitted through a silver salt film or diazo film which is a master film in which a circuit pattern is drawn in advance on the photosensitive resin stretched on the front and back of the copper clad laminate. After forming a latent image of the etching resist by irradiating with a light beam and exposing it, the etching resist of the etching resist is developed by using a solvent that dissolves the unexposed portion and does not dissolve the exposed portion, for example, a dilute alkaline aqueous solution such as sodium carbonate. A conductor circuit pattern is formed by forming a circuit pattern and etching the exposed metal portion. This method is called a tenting method and a dry film is used.

Further, a resin which is soluble in a solvent or an alkaline aqueous solution is filled in the conduction hole of the copper-clad laminate provided with the conduction hole to protect the inner wall of the conduction hole from the etching solution, and the front and back surfaces of the copper-clad laminate are exposed. Of a resin composition containing a conductive resin as a main component and drying the solution to form a master film in which a circuit pattern is drawn in advance on a photosensitive resin formed on the front and back surfaces of a copper-clad laminate, a silver salt film or diazo film Through an actinic ray such as ultraviolet rays to form a latent image of the etching resist, and then develop using a solvent that dissolves the unexposed area and does not dissolve the exposed area, for example, a dilute aqueous alkali solution such as sodium carbonate. Therefore, a method of forming a circuit pattern of an etching resist and etching the exposed metal portion to form a conductor circuit pattern is also partially performed.

A photosensitive resin composition film is formed on an inner wall of a conductive hole of a copper-clad laminate provided with a conductive hole by electrodeposition using a resin composition containing a photosensitive resin as a main component, and front and back surfaces of the copper-clad laminate. Then, the latent image of the etching resist is formed by irradiating with actinic rays such as ultraviolet rays through a silver salt film or a diazo film, which is a master film on which a circuit pattern is drawn in advance, and then the unexposed area is dissolved to expose the exposed area. A method of forming a circuit pattern of an etching resist by developing with a solvent that does not dissolve, for example, a dilute aqueous alkaline solution such as sodium carbonate, and forming a conductor circuit pattern by etching an exposed metal part is also performed. ing.

In the tenting method using a dry film, when the photosensitive resin composition film stretched over the opening of the through hole cannot be exposed in a sufficient area due to the misalignment of the master film, the photosensitive resin composition is developed by development. There was a problem that the film had pores and the etching solution permeated into the conductive hole to etch the metal on the inner wall of the conductive hole to cause a defect in the conductive hole.

The periphery of the opening of the through hole is called a land, and the diameter of the land is 0.2 to the diameter of the opening of the through hole.
It was designed to be 0.3 mm larger and allowed for some positional deviation, but in recent years the diameter of the through hole has been reduced, and the diameter difference between the land diameter and the through hole has been reduced to less than 0.2 mm. In addition, the number of wirings between the lands has been increased and the wiring density has been increased to design a printed wiring board by reducing the line width and the line spacing of the conductor circuit. In this tenting method, the tolerance of the deviation between the master film and the hole position of the conductive hole becomes small, and it is becoming difficult to produce with good yield.

On the other hand, a method of filling holes and applying and drying a liquid etching resist, or applying a photosensitive resin composition emulsified by electrodeposition to form a film of the photosensitive resin on the inner walls of the conductive holes and the front and back surfaces of the copper clad laminate. The method of forming a conductive circuit forming method for producing a printed wiring board having a high wiring density without the problem of conductive hole loss due to the etching liquid flowing into the conductive hole due to the positional deviation between the mask film and the through hole opening. Is being considered as.

However, a long process of filling holes and drying, polishing the surface and applying and drying a liquid etching resist is required, and the filled resin needs to be removed by peeling after etching, resulting in poor productivity. The formation of the photosensitive resin film by electrodeposition requires a large-scale device itself, and complicated liquid management and the like cannot be used easily.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides a high-density printed wiring board, particularly a memory card, which does not cause a defect in the inner wall of the conductive hole even when the master film is displaced and does not require a long process. Provided is a printed wiring board intermediate material for forming a conductive circuit of a thin plate such as the following, and a method for manufacturing the printed wiring board intermediate material.

[0011]

Means for Solving the Problems That is, according to the present invention, a copper-clad laminate is provided with through-holes, and a copper-clad laminate having conductive holes formed on the front and back sides thereof by electroless plating and electrolytic plating or electroless plating It is a printed wiring board intermediate material with a photosensitive resin film formed on the front and back surfaces and the inner walls of the conduction holes, which is formed by applying an etching resist and drying it. A method for producing a printed wiring board intermediate material, comprising applying a liquid etching resist to the inner wall of the conduction hole by applying a liquid etching resist to the copper-clad laminate having the conduction holes formed by using a coating means capable of simultaneously forming both surfaces. And preferably relates to a method for producing an intermediate material for a printed wiring board, wherein the coating means is a roll coater or a dip coater.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid etching resist used in the present invention is a solvent solution containing a photosensitive resin composition,
It contains fine particles of an inorganic or organic substance and has a structural viscosity. The viscosity of the liquid etching resist may be appropriately small and is usually 0.01 to 60 cPa · s.

According to the present invention, a through hole is formed in a copper-clad laminate,
By applying a liquid etching resist to a copper-clad laminate having electroconductive and electroless plating or electroless plating to form conduction holes on the front and back sides using a coating means capable of forming both sides simultaneously, the front and back surfaces and inner walls of the conduction holes are coated. Thus, it is possible to manufacture the printed wiring board intermediate material on which the photosensitive resin film is formed.

As a coating means which can be applied to both sides simultaneously, a roll coater having a pair of rolls having grooves formed therein, or a dip coater which is immersed in a liquid pool and pulled up is preferably used.

As a method for drying the liquid etching resist applied to the copper-clad laminate, hot air drying, far infrared ray drying or the like is preferably used to avoid curing by heat.
It is preferable to dry at 0 ° C or lower and 60 ° C or higher in consideration of the drying time. By drying in this way, a film of the photosensitive resin composition can be formed on the inner wall of the conductive hole.

A method of forming a photosensitive resin composition film as an etching resist pattern by using a printed wiring board intermediate material having a photosensitive resin film formed on the front and back surfaces and the inner wall of the conductive hole is as follows. It exposes with actinic rays, such as ultraviolet rays, through the drawn master film. At this time, the through-holes in which it is necessary to form the through-holes are removed from the through-hole positions of the master film so that the active rays can pass through the through-holes. In addition, the through holes that are not the conductive holes block the positions of the through holes of the master film.

Next, the unexposed portion and the unexposed through-holes are washed (developed) by spraying or immersing the unexposed portion in a weak alkaline aqueous solution such as an organic solvent or an aqueous sodium carbonate solution, and shaking. The film of the photosensitive resin composition is removed. Incidentally, the exposed circuit pattern and the inside of the through hole to be a conductive hole remain without being removed by the development of the photosensitive resin composition film.

Next, a ferric chloride hydrochloric acid solution, a cupric chloride hydrochloric acid solution, or a mixed solution of sulfuric acid and hydrogen peroxide water is added to the mixture.
The exposed front and back of the copper-clad laminate and the through holes are formed by corrosively dissolving the exposed metal copper with a general etching solution for the metal copper at 0 to 50 ° C.

Liquid etching resist is applied to the front and back of the copper-clad laminate having the through holes in this way by a roll coater or a dip coater at the same time and dried to easily form a printed wiring board having the through holes. It is possible to provide a method for easily forming a conductive circuit of a high-density printed wiring board without causing a defect in the inner wall of the conductive hole even when the master film is displaced, which is the subject of the invention, and does not require a long process. You can do it.

[0020]

EXAMPLES A printed wiring board intermediate material of the present invention and a method for manufacturing the same will be described below with reference to the sectional views including a partially enlarged through hole in which the same parts as those in the examples and comparative examples are designated by the same reference numerals. [Embodiment 1] As shown in FIG. 1, through holes having hole diameters of 1.5 mm and 0.3 mm are formed, copper plating or copper foil layer 3 is formed, and conductive holes 1 and 0. 3 mm
Liquid etching resist (MT manufactured by Mitsui Toatsu Kagaku Co., Ltd.) was applied to a copper-clad laminate 4 having a thickness of 0.8 mm and having a .phi.
UV-6102, viscosity 40 cPa.s) was applied. The drying was performed by far infrared rays at 100 ° C. for 3 minutes. FIG. 5 shows the coated state of the photosensitive resin composition film 9 after drying. This is an intermediate material for a printed wiring board in which a photosensitive resin film is formed on the front and back surfaces and the inner wall of the conduction hole. Pore diameter 1.5m
In the mΦ conduction hole 1, the inner wall was covered, and in the conduction hole 2 having a hole diameter of 0.3 mmΦ, the conduction hole was closed and filled. Next, the master film 7 was shifted and exposed for 15 seconds using an exposure machine HMW-201 manufactured by Oak. Ultraviolet rays permeate from the blank portion of the master film, and the portion of the photosensitive resin composition film exposed to ultraviolet rays cures. The state of exposure is shown in FIG. After exposure, it was developed for 40 seconds with a 1% by weight sodium carbonate aqueous solution at 30 ° C. The state of the etching resist pattern 10 formed of the liquid etching resist after development is shown in FIG. The etching resist pattern 10 made of the liquid etching resist has no defects such as falling off even when it is in contact with the edge of the conductive hole, and since the conductive hole is covered, disconnection of the conductive hole due to etching does not occur.

Example 2 A liquid etching resist (MTUV61 manufactured by Mitsui Toatsu Kagaku Co., Ltd.) was prepared using the dip method.
03, diluted with acetone to adjust the viscosity to 0.3 cPa · s) was applied to the copper-clad laminate 4 having the same conductive holes as in Example 1. This copper-clad laminate is used in a far-infrared furnace for 10
It was dried at 0 ° C. for 4 minutes to form a photosensitive resin composition film 9. FIG. 8 shows the formation state of the photosensitive resin composition film 9 formed on the copper-clad laminate 4 having the through holes. This is an intermediate material for a printed wiring board in which a photosensitive resin film is formed on the front and back surfaces and the inner wall of the conduction hole. The photosensitive resin composition film 9 is formed on the inner wall of the conductive hole in the conductive hole 1 having a hole diameter of 1.5 mmΦ, and the conductive resin composition film 9 is formed on the inner wall of the conductive hole in a state in which the film is formed in the central portion of the conductive hole 2 having a hole diameter of 0.3 mmΦ. Photosensitive resin composition film 9
Has been formed.

Next, the master film 7 was shifted and exposed for 15 seconds using an exposure machine HMW-201 manufactured by Oak Corporation. The state of exposure is shown in FIG. After exposure, it was developed for 40 seconds with a 1 wt% sodium carbonate aqueous solution at 30 ° C. FIG. 10 shows the state of the etching resist pattern 10 formed with the liquid etching resist after development. Even if the etching resist pattern 10 on the conductive hole is in contact with the conductive hole, it does not have defects such as falling off, protects the metal layer on the inner wall of the conductive hole against etching, and does not cause defects such as disconnection.

COMPARATIVE EXAMPLE A copper-clad laminate having the same conductive holes as in Example 1 was thermocompression-bonded with a dry film, which is generally used, to form a photosensitive resin composition film 5.
Was formed. In the case of a dry film, a polyester protective film 6 is formed on the photosensitive resin composition film 5. FIG. 2 shows a state in which the photosensitive resin composition film 5 and the protective film 6 are formed by using a dry film on the copper-clad laminate 4 having the through holes.

Next, the copper-clad laminate having the through holes is
The master film 7 is shifted and the exposure machine HMW- manufactured by Oak Co., Ltd.
Exposure at 201 for 15 seconds. The state of exposure is shown in FIG.

After the exposure, it was developed for 40 seconds with a 1% by weight sodium carbonate aqueous solution at 30 ° C. FIG. 4 shows a state in which an etching resist pattern 8 formed by a dry film by exposure and development is formed. The etching resist pattern 8 formed by a dry film in which the photosensitive resin composition film on the conductive hole is cured by exposure by development. Was missing.

[0026]

INDUSTRIAL APPLICABILITY The present invention applies a liquid etching resist to a copper-clad laminate having a conductive hole formed therein by using a coating means such as a roll coater or a dip coater capable of simultaneously forming both surfaces, and then the inner wall of the conductive hole and the copper-clad laminate are dried. By forming a photosensitive resin layer on the surface of the laminated plate, it is possible to form conductive holes even when the mask film is displaced, and it is also possible to form many wirings between lands by designing small lands. It has become possible to provide an intermediate material for processing printed wiring boards, which enables electronic components to be mounted at a high density, and also facilitates the formation method thereof.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a copper-clad laminate having a through hole.

FIG. 2 is a partially enlarged sectional view of a state in which a layer of a photosensitive resin composition film is formed.

FIG. 3 is a partially enlarged cross-sectional view of a state after the photosensitive resin composition film is irradiated with ultraviolet rays.

FIG. 4 is a partially enlarged sectional view showing how an etching resist pattern is drawn.

FIG. 5 is a cross-sectional view partially enlarging the covering state of the photosensitive resin composition film centering on the conduction hole.

FIG. 6 is a partially enlarged sectional view showing how an etching resist pattern is drawn.

FIG. 7 is a partially enlarged cross-sectional view of a state in which an unexposed portion is washed away with a developing solution to form an etching resist pattern.

FIG. 8 is a cross-sectional view in which the film state of the photosensitive resin composition film is partially enlarged centering on the conduction hole.

FIG. 9 is a partially enlarged cross-sectional view showing how an etching resist pattern is drawn.

FIG. 10 is a partially enlarged cross-sectional view of a state where an unexposed portion is washed away with a developing solution to form an etching resist pattern.

[Explanation of symbols]

1 Conduction hole with a hole diameter of 1.5 mmΦ 2 Conduction hole with a hole diameter of 0.3 mmΦ 3 Copper plating or copper foil 4 Insulating layer 5 Photosensitive resin composition film made of dry film 6 Protective film used for dry film 7 Master film 8 Etching resist pattern by dry film 9 Photosensitive resin composition film formed by liquid etching resist 10 Etching resist pattern formed by liquid etching resist

Claims (4)

[Claims] 1. A copper-clad laminate having through holes formed therein, and a copper-clad laminate having conductive holes formed on the front and back sides thereof by electroless and electrolytic plating or electroless plating, is coated with a liquid etching resist and dried. An intermediate material for a printed wiring board in which a photosensitive resin film is formed on the front and back surfaces and the inner wall of the conduction hole. 2. An inner wall of the conductive hole is formed by applying a liquid etching resist to a copper-clad laminate having conductive holes formed on the front and back sides by electroless and electrolytic plating or electroless plating using a coating means capable of simultaneously forming both surfaces. A method for manufacturing an intermediate material for a printed wiring board, which comprises applying a liquid etching resist to the substrate. 3. The method of manufacturing a printed wiring board intermediate material according to claim 2, wherein the coating means is a roll coater. 4. The method for producing a printed wiring board intermediate material according to claim 2, wherein the coating means is a dip coater.