JPH11177235A - Manufacture of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent burr or peel-off of a copper plating at working, by electro- depositing a photosensitive etching resist film on the surface of a copper plating layer of a through hole of a substrate, and exposing/developing and etching a part of it, in axial direction, at a facing inner wall part of the through hole crossing an outline cutting line, for removal. SOLUTION: On both front and rear surfaces of a board 1 and inner wall surfaces of a slot 2 and a round hole 3, a copper plating layer 4 is formed, and a photosensitive etching resist film 5 is electro-deposited on the surface of them. Then, at facing inner wall parts of the slot 2 and the round hole 3 crossing an outline cutting work line P, a part of the electro-deposition photosensitive etching resist film 5 is exposed/developed by an appropriate width in axial direction. Then etching is processed in axial direction for a part of it to be removed. Then, by peeling the photosensitive etching resist film 5, a printed wiring board comprising a connection end surface formation through hole in such condition as a part of it is removed in axial redirection at the facing inner wall parts where the copper plating of the slot 2 and the round hole 3 crosses the outline cutting work line P is provided.

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 having a through hole in which a connection end face is formed by cutting an outer shape.

[0002]

2. Description of the Related Art Conventionally, a printed wiring board having a connection surface at an end face is generally formed by forming a copper plating layer on an inner wall surface of a through hole, and then cutting the through hole located on an outline cutting line by a router process or the like. Was manufactured by
However, according to this method, it is difficult to obtain a printed wiring board having excellent end face accuracy because copper plating is easily turned or peeled off during the outer shape cutting process.

Therefore, in order to prevent the copper plating from being turned up or peeled off, a copper plating layer is formed in recent years, and then a material having a different melting property from that of the printed wiring board structure is filled in the through hole. The outer shape is cut as it is,
Thereafter, a method of removing the filler has already been reported (JP-A-4-247693). However, according to this method, a step of filling foreign matter into the through-hole and a step of removing the filling are required, so that at least two more steps are added in a normal printed wiring board manufacturing process. There was a problem that efficient production was difficult.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances and problems, and is intended for forming a connection end face which does not cause copper plating to be turned up or peeled off during external cutting. It is an object of the present invention to provide a method capable of efficiently manufacturing a printed wiring board having a through hole without adding a special number of steps.

[0005]

In order to achieve the above object, the present invention provides a method in which a photosensitive etching resist film is applied to the surface of a copper plating layer of a substrate having a through hole having a copper plating layer formed on an inner wall surface. A step of axially exposing and developing a part of the electrodeposited photosensitive etching resist film at an inner wall portion facing the through hole intersecting with the outer shape cutting processing line; and performing an etching process after the exposure and development. And removing the copper plating of the through-holes partially in the axial direction at the opposed inner wall portion, thereby forming a method of manufacturing a printed wiring board having a through-hole for forming a connection end face.

According to this configuration, since the copper plating at the externally cut portion of the through hole can be accurately removed, there is no occurrence of the conventional copper plating being turned up or peeled off during the external cutting process. Further, the electrodeposition step of the photosensitive etching resist film, the exposure and development step of the electrodeposited photosensitive etching resist film and the etching process step,
The through-holes are provided at the connection end surface without adding a special number of steps by performing the steps together with the electrodeposition step of the photosensitive etching resist film for circuit formation, the exposure / development step of the electrodeposited photosensitive etching resist film, and the etching processing step. A printed wiring board can be manufactured efficiently.

The through hole in the present invention is not limited to a specific shape such as a round hole, a square hole, and a long hole.
An elongated hole formed by a continuous circular arc is formed. However, due to the presence of the protruding inner wall portion at the connecting portion of the circular arc, extra light spills to an unnecessary portion when exposing the electrodeposited photosensitive etching resist film. This makes it possible to perform more accurate exposure and development processing, and when the outer shape cutting is performed by press punching, the number of surfaces in contact with (contacting) the upper die of the die is reduced, and as a result, the This is particularly advantageous in that the load on the device can be further reduced.

The photosensitive etching resist film used in the present invention may be of a positive type or a negative type, but a positive type is particularly preferred in that it has a small thickness, excellent sensitivity and low tackiness. It is preferably used.

[0009]

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

1 (A) to 1 (F) are plan explanatory views showing the steps of a manufacturing process of a printed wiring board according to the present invention, and FIGS. 2 (a) to 2 (f) are FIGS. 1 (A) to 1 (f), respectively. FIG. 2 is a cross-sectional explanatory view taken along an outline cutting processing line of a round hole corresponding to (F). First, as shown in FIGS. 1A and 2A, a drill is placed on an outline cutting processing line P of a substrate 1. Then, a number of elongated holes 2 and round holes 3 formed by continuous arcs are appropriately formed.

Next, as shown in FIGS. 1B and 2B, a copper plating layer 4 is formed on both the front and back surfaces of the substrate 1 and the inner wall surfaces of the elongated holes 2 and the round holes 3.

Next, as shown in FIGS. 1C and 2C, a photosensitive etching resist film 5 is electrodeposited on the surface of the copper plating layer 4 on the substrate 1 and the long holes 2 and the round holes 3.

Next, as shown in FIGS. 1D and 2D, a long hole 2 and a round hole 3
In the opposed inner wall portions 2a, 2b; 3a, 3b, a part of the electrodeposited photosensitive etching resist film 5 is exposed and developed in an appropriate width in an axial direction. The exposure and development are performed simultaneously with the exposure and development for forming the circuit.

Next, as shown in FIGS. 1 (E) and 2 (e), copper plating of the long hole 2 and the round hole 3 is carried out by etching and the shafts are formed at the opposed inner wall portions 2a, 2b; 3a, 3b. Partially removed in the direction. This etching is performed simultaneously with the etching for forming the circuit.

Next, as shown in FIGS. 1F and 2F, when the photosensitive etching resist film 5 is peeled off,
Through-holes for forming connection end faces (elongated holes) in which the copper plating of the elongated holes 2 and the round holes 3 are partially removed in the axial direction at the opposing inner wall portions 2a, 2b; 2 and a printed wiring board having a round hole 3) are obtained.

[0016]

According to the method of manufacturing a printed wiring board of the present invention, it is possible to accurately remove the copper plating at the externally cut portion of the through hole for forming the connection end face without adding a special number of steps. In addition, a printed wiring board having a through-hole for forming a connection end face where no copper plating is present at an outer shape cutting portion can be efficiently manufactured.

When the printed wiring board thus manufactured is used, since copper plating does not exist in the external cutting portion of the through hole for forming the connection end face, the copper plating is turned or peeled off by the external cutting process. A printed wiring board having an end face with high connection reliability can be obtained without occurrence.

[Brief description of the drawings]

FIGS. 1A to 1F are plan explanatory views showing a procedure of a manufacturing process of a printed wiring board of the present invention.

2 (a) to 2 (f) are (A) to FIG. 1 respectively.
Sectional explanatory drawing which follows the contour cutting processing line of the round hole part corresponding to (F).

[Explanation of symbols]

 1: substrate 2: long hole 2a, 2b: opposed inner wall 3: round hole 3a, 3b: opposed inner wall 4: copper plating layer 5: photosensitive etching resist film P: external cutting line

Claims (4)

[Claims] 1. A step of electrodepositing a photosensitive etching resist film on a surface of a copper plating layer of a substrate having a through hole having a copper plating layer formed on an inner wall surface, and an inner wall opposed to the through hole intersecting with an external cutting line. Exposing and developing a part of the electrodeposited photosensitive etching resist film in the axial direction at the portion, and etching and subjecting the exposed portion to the copper plating of the through hole in the axial direction at the opposed inner wall portion after the exposure and development. A method of manufacturing a printed wiring board having connection end face forming through holes. 2. The printed wiring board according to claim 1, wherein the through holes for forming connection end faces are round holes, square holes or elongated holes. 3. The printed wiring board according to claim 2, wherein the elongated hole is formed by a continuous arc. 4. The step of electrodepositing the photosensitive etching resist film, the step of exposing / developing the electrodeposited photosensitive etching resist film and the step of etching are each performed by the step of electrodepositing a photosensitive etching resist film for forming a circuit. The method according to any one of claims 1 to 3, wherein the method is performed together with the step of exposing and developing the electrodeposited photosensitive etching resist film and the step of etching.