JPH0645729A - Manufacturing method of printed-wiring board - Google Patents

Abstract

PURPOSE:To augment the bonding power of a resist on a bonding surface by reducing and unifying the roughness on the resist bonding surface as well as depriving the roughness of its directivity for avoiding the immersion of a solution and increasing the pattern roughness. CONSTITUTION:Within the forming method of a circuit pattern by forming a photoresist on a copper plating laminated plate, the copper plating laminated plate is roughened by chemical processing step as the preliminary processing of the photoresist forming step and then the photoresist is to be formed on the roughened surface for the pattern formation.

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 performs a pretreatment for forming a photoresist for pattern formation.

[0002]

2. Description of the Related Art Printed wiring boards used in various electronic devices have been promoted in miniaturization and high functionality of electronic components, and with the progress of high-density mounting technology for these components, high-density printed wiring boards have been developed. The demand for is getting stronger. Since a high-density printed wiring board is formed by a subtractive method or an additive method and has features such as miniaturization of electronic parts, various manufacturing methods have been studied. In all of these methods, a photoresist for pattern formation is formed on a copper clad laminate, and this is developed to form a pattern.

As a pretreatment method for photoresist formation for pattern formation in such a method for producing a printed wiring board, buffing by mechanical polishing is performed, then photoresist is laminated, mask films are aligned and exposed. There are a tenting method of developing and etching to form a pattern, or a metal resist method of performing pattern copper plating and solder plating after development.

In this case, a tenting method by mechanical polishing is used as a pretreatment method for photoresist formation, in which the pattern forming process liquid penetrates into the interface between the photoresist and the polishing surface along the roughness direction of the polishing surface. There are defects such as chipping of the pattern and disconnection. On the other hand, in the pattern formation of the metal resist method by mechanical polishing, the plating solution penetrates into the interface between the photoresist and the polishing surface during pattern copper plating and solder plating, copper and solder are deposited, and pattern thickening and pattern There is a drawback that leads to a short circuit, etc.

[0005]

As described above, in the conventional method for manufacturing a printed wiring board, the roughening method by mechanical polishing, which is a pretreatment method for photoresist formation, is the tenting of the subtraction method for circuit formation. Method and the metal resist method, the pattern forming step liquid penetrates into the interface between the resist and the polishing surface along the roughness direction of the polishing surface,
The adhesion of the resist is reduced due to the floating of the resist,
There are problems such as chipping of the pattern, disconnection, thickening, and short circuit.

The present invention has been made in order to solve the above problems in pattern formation in a method for manufacturing a printed wiring board, and reduces the roughness of the resist contact surface and makes it uniform as compared with the conventional mechanical polishing. It is an object of the present invention to obtain a method for manufacturing a printed wiring board, which can reduce the roughness direction and improve the adhesive force of the resist on the contact surface, thereby improving the pattern accuracy.

[0007]

The present invention is the following method for manufacturing a printed wiring board. (1) In a method for manufacturing a printed wiring board in which a photoresist is formed on a copper-clad laminate to form a circuit pattern, the copper-clad laminate is roughened by chemical treatment as a pretreatment for photoresist formation. A method for manufacturing a printed wiring board, wherein a photoresist is formed on a roughened surface to form a pattern. (2) The method for producing a printed wiring board according to (1) above, wherein the chemical treatment is black oxide treatment, plating treatment without addition of a brightening agent, or soft etching treatment with ferric chloride.

[0008]

In the method of manufacturing a printed wiring board according to the present invention, the copper surface of the copper clad laminate is roughened by performing a chemical treatment before forming a photoresist for forming a pattern. As the chemical treatment, a blackened film is formed by black oxide treatment, and as a means for further improving the adhesion, first,
After formation of the blackening film, there are a method of dissolving the surface layer with an acid to remove the metal oxide film, a method of performing a plating treatment without adding a brightening agent, a method of soft etching with ferric chloride. After roughening by these chemical treatments,
A photoresist is laminated on the roughened surface and a desired pattern is formed to manufacture a printed wiring board.

In the present invention, by performing a chemical treatment before forming a photoresist for pattern formation, the roughness of the resist contact surface is reduced, the roughening is made uniform, and the directionality of the roughened surface is dispersed. Be converted. As a result, the pattern forming process liquid after resist lamination is prevented from entering the interface between the roughened surface and the resist, and the adhesion of the pattern forming resist is improved.

[0010]

EXAMPLES Example 1 Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples. 1) After forming through holes on the copper clad laminate and performing through hole plating, degreasing, washing with hot water, washing with water, dilute sulfuric acid treatment, washing with water,
After black oxide treatment with sodium hydroxide and washing with water, it is immersed in 10 wt% hydrochloric acid for 3 to 5 seconds to dissolve the blackened film, and then washed with water, diluted sulfuric acid, washed with water,
Drying was performed to roughen the copper surface. Then, a photoresist was laminated on the roughened surface, and a desired pattern was formed by a metal resist method.

By this chemical treatment, a uniform roughened surface having a roughness of 0.1 micron or less can be obtained, which prevents the metal resist solution from infiltrating into the interface between the photoresist for pattern formation and the roughened surface, and a good circuit can be obtained. The pattern was obtained.

Example 2 After forming through-holes on a copper-clad laminate and performing through-hole copper plating, using a copper sulfate plating solution containing no brightening agent prepared in another bath in advance, the copper surface has a thickness of 1 micron or less. Plating was applied to roughen the copper surface. Then dry it
A photoresist was laminated, and the same operation as in Example 1 was performed to form a pattern. In this case, in the copper plating without the addition of the brightening agent, the crystal particles of the copper plating become large, the plating surface is roughened, and the adhesion is improved. However, the plating thickness is preferably 1 micron or less, and if it is thick, delamination occurs between the copper platings.

Example 3 As a chemical treatment, a soft etching of 1 to 1.5 μm was performed with a ferric chloride solution, and the same operation as in Example 1 was performed to form a pattern.

When conventional mechanical polishing is performed as a photoresist pretreatment, the roughness of the roughened surface becomes 1.5 to 2.0 μm, and the roughness directions of the roughened surface become the same. The pattern forming process liquid in the subsequent process penetrates into the roughened surface and the photoresist interface, and causes a pattern defect. When the roughness of mechanical polishing is 1 micron or less, the adhesiveness is significantly reduced.

On the other hand, by performing the chemical treatment of Examples 1 to 3, the roughness of the roughened surface becomes 0.1 micron or less, and the roughness becomes more uniform. By reducing the roughness and making it uniform, the infiltration of the pattern forming process liquid is prevented, and the pattern accuracy is improved.

Further, since the oxide film formed by the chemical treatment has extremely high solubility with respect to acid, the adhesiveness between the photoresist and the copper on the roughened surface is further improved by dissolving and removing the oxide film with acid. To do.

In the above description, as the chemical treatment, the plating treatment without the addition of the black oxide treatment brightener and the soft etching treatment are shown, but the surface may be roughened by another chemical treatment.

[0018]

According to the method for manufacturing a printed wiring board of the present invention, since roughening is performed by a chemical treatment as a photoresist pretreatment, the roughness of the roughened surface is reduced to be uniform and It is possible to eliminate the directionality of the thickness, thereby improving the adhesiveness of the resist, preventing the infiltration of the pattern forming process liquid between the roughened surface and the photoresist, and improving the pattern accuracy.

Claims (2)

[Claims] 1. A method of manufacturing a printed wiring board, wherein a photoresist is formed on a copper-clad laminate to form a circuit pattern, and the copper-clad laminate is roughened by chemical treatment as a pretreatment for photoresist formation. And forming a photoresist on the roughened surface to form a pattern, the method for producing a printed wiring board. 2. The method for producing a printed wiring board according to claim 1, wherein a black oxide treatment, a plating treatment without adding a brightening agent, or a soft etching treatment with ferric chloride is performed as the chemical treatment.