JPH10335786A - Manufacture of high-density printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form conductor pattern which are excellent in physical characteristics are solid and are microscopic, on a substrate with good productivity in a short time, by a method wherein a photo solder resist is applied on the substrate to form wiring resist patterns on the substrate by a photolithography technique, and a copper plated film is formed on the substrate using together a chemical copper plating and an electrolytic copper plating. SOLUTION: A photo solder resist 4 is applied on both surfaces of a substrate 1. A sensitizing treatment and a developing treatment are performed on the photo solder resist 4 using a photomask, and plated resist patterns 5 for microscopic wiring are formed on the surface of the substrate 1. Moreover, after a very thin chemical copper plated layer is formed on the surface of the substrate by a chemical copper plating applied in the manufacture of a normal printed wiring board, an electrolytic copper plating is applied to the plated layer. In such a way, the photo solder resist is applied on the surface of the substrate to form the solder resist patterns 5 for wiring and component mounting on the surface of the substrate, whereby a highly reliable high-density printed wiring board can be obtained.

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 fine wiring method using an additive method in which only a required wiring portion of a substrate material is selectively plated with copper to form a conductive wiring pattern. The present invention relates to a method for manufacturing a high-density, high-reliability, low-cost printed wiring board capable of easily forming a high-density wiring.

[0002]

2. Description of the Related Art Conventionally, for forming a fine wiring circuit (for example, a circuit width of 50 μm or less) of a printed wiring board, generally,
An additive method by a completely electroless plating method (a method of forming a conductor wiring pattern only on a required wiring portion of a substrate material by selective copper plating) is suitable. However, this additive method is produced, for example, by steps shown in FIGS. That is, a laminated plate with an adhesive containing a catalyst (FIG. 3A) was used as the substrate 11, and after the holes 13 were formed by punching [FIG.
(B)], a photoresist is applied, a plating resist pattern 14 is formed to define a region to be subjected to chemical copper plating [FIG. 3 (c)], and a chemical copper plating 15 is applied to form a wiring pattern [ In FIG. 3D, a printed wiring board has been manufactured by a process of applying a photo solder resist on the substrate surface to form a solder resist pattern [FIG. 3E]. The printed wiring board manufactured in this manner has the following problems, and has not been particularly applied to a high-density printed wiring board of an electronic device or the like that requires reliability. (1) Since copper plating is only a chemical (electroless) plating method, physical properties are inferior to electric (electrolytic) plating, and thus the reliability as a printed wiring board is low. (2) Since it is a chemical copper plating, a long plating time is required, a long time is required for manufacturing a printed wiring board, and productivity is low. (3) Special production control is required because a substrate containing a catalyst and an adhesive is used as the substrate material.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to selectively apply a chemical (electroless) copper plating only to a required wiring portion of a conventional substrate material and to print by an additive method of forming a conductor wiring pattern. It solves the problem of the method of manufacturing a wiring board, and does not use a laminated board with an adhesive containing a catalyst that requires special production control as a board material, and also requires a long plating time for chemical copper. The formation of the conductor pattern only by plating method is renewed, and using the board material used in the manufacture of a normal printed wiring board, a photo solder resist (applied to the surface of the outermost layer of the board and patterned by photo method) Solder resist), apply a photolithography technique to form a plating resist pattern, and then perform chemical copper plating and electrolytic copper plating Combined use of these enables the formation of robust and fine conductor patterns with excellent physical properties in a short time with good productivity, making it possible to easily produce high-density, high-performance, highly reliable printed wiring boards in a short delivery time. It is an object of the present invention to provide a method of manufacturing a printed wiring board which can be manufactured.

[0004]

Means for Solving the Problems In order to achieve the object of the present invention, the present invention is configured as described in the claims. That is, the present invention provides a method for manufacturing a printed wiring board having both functions of wiring and component mounting, wherein a photo solder resist is applied on a predetermined board, and a photolithography technique is used. Robust copper plating with excellent physical properties, with a service life more than twice as long as the conventional additive copper chemical plating only, using a process of forming a wiring resist pattern with chemical copper plating and electrolytic copper plating Forming a wiring pattern by repeating the step of forming a layer and the step of removing an unnecessary portion of the copper plating layer on the substrate at least once or more; and forming a wiring and a solder for mounting components on the substrate. A method of manufacturing a high-density printed wiring board including at least a step of forming a resist pattern. Further, the present invention provides the first aspect as described in the second aspect.
A method for manufacturing a high-density printed wiring board, comprising the step of reducing the thickness of an initial copper plating layer, in which chemical copper plating and copper electroplating are used together, to 以下 or less of the required copper plating layer thickness It is assumed that. The method for manufacturing a high-density printed wiring board according to the present invention includes, as described in claim 1, a step of forming a fine wiring resist pattern by a photolithography technique using a photo solder resist; To form a fine wiring pattern by repeating a process of forming a robust copper plating layer having excellent physical properties and then removing unnecessary portions of the copper plating layer at least once on the substrate at least once or more. A fine wiring circuit with a width of about 30 μm can be easily formed with high precision, and chemical copper plating and electric (electrolysis)
Since copper plating is used in combination, a fine wiring pattern having good physical characteristics can be produced, so that occurrence of disconnection failure of a fine wiring circuit can be suppressed, and a highly reliable high-density printed wiring board can be obtained. effective. Furthermore, the combined use of electrolytic copper plating shortens the time of the copper plating step, and thus has the effect of improving productivity. Further, as set forth in claim 2, the present invention reduces the thickness of the first electrolytic copper plating layer using both chemical copper plating and electrolytic copper plating to １ ／ or less of the thickness of the required copper plating layer. Adjustment, and further, a copper plating layer is repeatedly laminated thereon, so that a dense copper wiring pattern with excellent physical properties can be obtained, which has the effect of realizing a highly reliable high-density printed wiring board. .

[0005]

1 (a) to 1 (e) and FIG.
(F) to (i) show an example of a manufacturing process of the high-density printed wiring board of the present invention. The method for manufacturing a high-density printed wiring board of the present invention uses a photo solder resist (a solder resist that is applied to the outermost layer surface of a printed wiring board and patterned by a photographic method) instead of the plating resist used in the conventional additive method. Then, a fine conductor wiring pattern is formed, and then the combined use of the chemical copper plating and the electrolytic copper plating used in the normal printed circuit board manufacturing process is used, compared with the conventional additive method only of the chemical copper plating. A process of forming a robust conductor wiring pattern with excellent physical characteristics with a service life more than twice as long, in a relatively short time, and mechanically polishing and removing unnecessary portions of copper plating (generally, copper plating of printed wiring boards) Using a polishing machine with a buff roll used for polishing), a step of using both the chemical copper plating and the electrolytic copper plating, and High-density and fine wiring including a step of repeating the step of mechanically polishing and removing unnecessary portions of copper plating at least once or more, and a step of forming a wiring and a solder resist pattern for component mounting on the substrate surface This is a method for producing a printed wiring board having the following. Here, an example of a method for manufacturing a high-density wiring of the present invention will be described with reference to FIGS. 1 (a) to 1 (e) and 2 (f) to 2 (i). FIG. 1A shows a configuration of a laminated board in which a copper foil 2 is stretched on both sides of a laminated board made of a glass epoxy material used as a substrate (copper-clad laminated board) 1. FIG.
(B) shows a state in which a hole 3 for forming a through hole is formed, and the copper foil 2 is removed by etching with a chemical solution. FIG. 1C shows a state where the photo solder resist 4 is applied to both surfaces of the substrate 1. FIG. 1 (d) shows that a photomask is used for the photo solder resist 4.
A state is shown in which a plating resist pattern (solder resist pattern) 5 for fine wiring is formed by performing exposure and development processes, and the plating resist pattern 5 is dried and cured.
FIG. 1E shows a case where an extremely thin chemical copper plating layer is formed by chemical copper plating performed in the manufacture of a normal printed wiring board, and then electrolytic copper plating is performed. In addition, the thickness of the electrolytic copper plating layer at this point is set to be equal to or less than の of the required copper plating thickness. FIG. 2F shows a state where an unnecessary copper plating layer deposited on the plating resist pattern 5 is mechanically polished and removed. FIG. 2G shows a step of repeatedly performing the copper plating shown in FIG. 1E again. FIG. 2 (h)
The step of repeatedly performing the polishing in FIG. 2F again is shown. 1 (e), 2 (f), 2 (g), and 2 (h) are repeated to form a fine wiring having a copper plating layer having a desired thickness. After going,
As shown in FIG. 2 (i), a highly reliable high-density printed wiring board is obtained by applying a solder resist on the surface of the substrate and forming a solder resist pattern 9 for wiring and component mounting on the surface of the substrate. Can be

[0006]

The method for manufacturing a high-density printed wiring board according to the present invention has the following effects. (1) A fine wiring circuit can be easily formed with high precision. (2) Since a fine wiring circuit having excellent physical characteristics can be formed by using electric (electrolytic) copper plating together, a highly reliable high-density printed wiring board can be obtained. (3) The time of the copper plating process is shortened, and the productivity is improved. (4) The occurrence of disconnection failure of the fine wiring circuit is reduced, and the reliability is improved. (5) In addition, it is easy to control the electrical characteristics (such as impedance) of the wiring circuit.

[Brief description of the drawings]

FIG. 1 is a process chart showing a manufacturing process of a printed wiring board exemplified in an embodiment of the present invention.

FIG. 2 is a process chart showing a manufacturing process of the printed wiring board exemplified in the embodiment of the present invention.

FIG. 3 is a process diagram showing a process for manufacturing a conventional printed wiring board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate (copper laminated board) 2 ... Copper foil 3 ... Hole 4 ... Photo solder resist 5 ... Plating resist pattern (solder resist pattern) 6 ... Laminated body of chemical copper plating and electrolytic copper plating 7 ... Chemical copper plating and electricity Copper plating laminate 8 ... Through hole 9 ... Solder resist pattern 11 ... Substrate (laminate plate with adhesive containing catalyst) 12 ... Adhesive 13 ... Hole 14 ... Plating resist pattern 15 ... Chemical copper plating layer 16 ... Through hole 17 ... Solder resist pattern

Claims (2)

[Claims] 1. A method for manufacturing a printed wiring board having both functions of wiring and component mounting, comprising: applying a photo solder resist on a predetermined substrate, and forming a wiring resist pattern by a photolithography technique. A process of using a chemical copper plating and an electrolytic copper plating together to form a robust copper plating layer having excellent physical properties with a service life more than twice that of the conventional additive copper plating, and Forming a wiring pattern by repeating the step of removing the unnecessary portion of the copper plating layer at least once or more, and a step of forming a solder resist pattern for wiring and component mounting on the substrate A method for manufacturing a high-density printed wiring board, comprising: 2. The method according to claim 1, wherein the thickness of the first electrolytic copper plating layer in which the chemical copper plating and the electrolytic copper plating are used together is not more than １ ／ of the required thickness of the copper plating layer. Method for manufacturing a high-density printed wiring board.