JP2002091020A - Method for producing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which allows a through-hole position and the through-hole position on design to directly coincide with each other in the film aligning in the case incapable of attaching a land pattern to a film for exposure. SOLUTION: Holes are formed at the positions on the film for exposure which correspond to the land positions. While directly confirming the deviation between the hole position and the through-hole position in the film matching, the operation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to the manufacture of printed wiring boards, and more particularly to the alignment of an exposure film during pattern exposure.

[0002]

2. Description of the Related Art In the manufacture of a printed wiring board, an exposure film (hereinafter referred to as a film) in which a pattern is preliminarily baked on the surface of a photosensitive resin film applied or affixed to the surface of a printed wiring board base material is exposed. The photosensitive resin film of the photosensitive portion is cured with, and the substrate is washed with a developing solution to remove the resin film of the light-shielding portion by the film. As a result, the pattern is combined with the film transparent portion pattern on the substrate surface. Is formed by a resin film. This step is used at a plurality of places in the manufacture of printed wiring boards, and is generally called a resist processing step. The purpose of resist processing is
Plating resists and etching resists are roughly classified into two types.The former plating resists are used for the purpose of plating the surface of a substrate other than the resin film pattern, with the formed resin film pattern acting as a resist to the plating solution. You. The latter etching resist is used for the purpose of removing the copper on the surface of the base material other than the resin film pattern by etching, with the formed resin film pattern acting as a resist to the etching solution.

[0003] Both the plating resist and the etching resist are important steps that affect the finishing accuracy of the printed wiring board, and in particular, the relative positioning accuracy of the printed wiring board base material and the film during exposure is important. The important reason is that the pattern is affected by various errors such as the expansion and contraction of the printed wiring board base, the expansion and contraction of the film, the accuracy of processing the position of the through-holes drilled in the base, and the positioning accuracy of the base and the film. This is because it appears as a difference between the design position and the finished product position. This finishing error is more remarkable as the size of the base material is larger, and as the number of laminations is larger, the influence of the expansion and contraction of the base material is greater, which greatly affects the production yield.

In order to make the finished product position as close as possible to the design position, a corrected film is used, film alignment is automated by optical reading, not only alignment marks but also holes for through holes in the base material. The production yield is improved by various methods such as matching with a film land pattern. Above all, the method of aligning the through-holes with the lands of the film is direct and highly effective, and has been often used.

[0005]

However, there are rare cases where a design in which a land is not provided on the film to match the through hole is used. An example in which a land pattern is not provided on a film is a film for partial plating. This is a printed wiring board in which electric contact pads are provided in a pattern of the printed wiring board, and the pads are plated with nickel and gold, and the other conductive patterns and the inner surfaces of the through holes remain copper. It is a film for partial plating when manufacturing a. FIG. 2 is a schematic diagram showing a partial manufacturing process of a printed circuit board with partial nickel / gold plating specifications.

In FIG. 2, (a) shows a part of a printed wiring board after a conductor pattern is formed, 11 is a printed wiring board base material, 12 is a through hole, 13 is a land, 14 is a pad, and 15 is a line. Show. 2 (b) to 2 (g) are cross-sectional views taken along the line AA in FIG. 2 (a), and FIG. (C) Exposure for forming a photosensitive resin film 17 on a copper-plated base material and applying nickel / gold plating to the surface corresponding to the pad 14 (D) A state in which the film 18 is aligned and exposed to light 19; (d) a state in which the exposed resin film 17 is developed and nickel plating and gold plating 20 are applied to the pad portion from which the resin film has been removed; A state in which a second photosensitive resin film 21 is formed and an exposure film 22 for forming a conductor pattern is aligned and exposed 23;
(F) shows a state in which the exposed resin film 21 is developed and the resin film is removed, and (g) shows a state in which the copper film is exposed and then the resin film 21 is peeled off.

In this case, since the land position is not indicated on the exposure film 18 for plating the surface corresponding to the pad 14 with nickel / gold plating, a method of adjusting the film 18 at the position of the through hole 12 is adopted. Can not. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a film positioning method for directly adjusting to a through hole of a printed wiring board even when a land pattern cannot be formed on the film.

[0008]

According to a first aspect of the present invention, there is provided a printed wiring board manufacturing method, wherein a through hole position is formed in an exposure film to be superimposed on a printed wiring board after a resist film is formed in a resist processing step which is a printed wiring board manufacturing step. In the case where the land corresponding to is not displayed, a hole is provided at a position on the exposure film corresponding to the through hole position.

According to the method of manufacturing a printed wiring board of the present invention, even if the land corresponding to the through-hole position is not displayed on the exposure film, the position of the through-hole on the printed wiring board and the design position of the through-hole on the exposure film are determined. Since the deviation can be directly confirmed visually, the probability of occurrence of a deviation outside the standard can be extremely reduced as compared with the conventional alignment mark alone.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, (a) is a plan view showing a part of a printed wiring board after a conductive pattern is formed, 1 is a base material, 2 is a through hole, 3 is a land, 4 is a pad, and 5 is a line. . FIG. 1B is a plan view showing an exposure film 6 for applying nickel plating and gold plating to the surface of the pad 4 and has a light-shielding portion 7 of the film and a hole 8 formed in the film. FIG. 1 (c)
Shows a plan view of a state in which the film 6 is overlaid on the base material 1 on which through-hole plating has been performed. FIG. 1 (d) is FIG. 1 (c)
9 is a cross-sectional view taken along the line A-A, where 9 indicates a photosensitive resin film and 10 indicates exposure.

In the hole 8 formed in the film shown in FIG. 1B, a through hole position is drawn on the film with small dots at the time of design, and a scope drill or the like is used to aim at the dot position on the film after drawing. And make a hole. The diameter of the hole 8 may be larger or smaller than the diameter of the through hole. In the figure, a portion with a hole diameter intermediate between the land diameter and the through hole diameter is shown.

In aligning the film 6 with the printed wiring board 1, alignment is performed with alignment marks provided outside the outer shape of the printed wiring board product, not shown in the figure, and the positions of the holes 8 and the through holes 2 made in the film are visually observed. Match.

[0013]

According to the present invention, even if the printed wiring board has a large size or a large number of laminations,
Since the deviation between the through hole position and the through hole design position can be directly confirmed at the time of film alignment, the occurrence of defective products due to the deviation can be reduced, and the production yield can be increased. In the case of the present embodiment, it is possible to easily and reliably suppress the deviation between the pad position and the nickel-gold plating position of the pad within the product standard.

[Brief description of the drawings]

FIG. 1 is a schematic front view and a sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a conventional partial gold plating process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Through hole 3 Land 4 Pad 5 Line 6 Exposure film 7 Light-shielding part of film 8 Hole in film 9 Photosensitive resin film 10 Exposure 11 Base material 12 Through hole 13 Land 14 Pad 15 Line 16 Copper foil and Copper plating 17 Photosensitive resin film (first time) 18 Exposure film (for pad portion plating) 19 Exposure 20 Nickel plating and gold plating 21 Photosensitive resin film (second time) 22 Exposure film (for conductor pattern formation) 23 Exposure

Claims (1)

[Claims] 1. In a resist processing step as a printed wiring board manufacturing process, when a land corresponding to a through hole position is not displayed on an exposure film to be superimposed on a printed wiring board after a resist film is formed, the land corresponds to the through hole position. Forming a hole at a position on the film for exposure.