JPS61265899A - Multilayer printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD The present invention relates to a multilayer printed circuit board used as a printed wiring board, and more particularly to an inner M reference hole of a multilayer printed circuit board.

[Technical background of the invention and its problems] Generally, when manufacturing a multilayer circuit board, it is required that the conductor patterns of each inner layer circuit board and the conductor pattern of the outermost layer maintain a predetermined vertical positional relationship. .

Therefore, when forming the outer layer circuit, a reference hole mark is placed in a part of the inner layer circuit board, and after multilayer molding, the reference hole mark is exposed with a drill, etc., and the reference hole mark is placed in the specified position while visually checking the exposed reference hole mark. However, since multilayer printed circuit boards are made by placing prepreg and copper foil on both sides of the inner layer circuit board and molding them together by heating and pressing, it is possible to form the outer layer circuit pattern from the copper foil surface. It was difficult to detect the position of the fiducial hole mark. Also, in order to make it easier to detect the position of the reference hole mark on the inner layer circuit board, there is a method of attaching mold release tape to the reference hole mark and molding it, and then cutting the bulge to expose it. There is a problem that the release tape may become misaligned and stick to the inner layer circuit.
Also, when placing the release tape, workability becomes worse,
In particular, when manufacturing by mass lamination, there are problems in terms of workability.

[Object of the Invention] The present invention has been made to solve the above-mentioned problems, and provides a multilayer printed circuit board in which an outer layer circuit can be easily formed by providing a reference hole on the exposed surface of the inner layer circuit board. The purpose is to

[Summary of the Invention] That is, the multilayer printed circuit board of the present invention is a multilayer printed board having at least one inner layer circuit board with prepreg arranged on both sides, and each of the inner layer circuit boards has a portion thereof on a side surface of the multilayer printed board. The inner layer circuit board is exposed, and at least one reference hole is formed in the exposed portion of each inner layer circuit board.

Since the present invention is characterized in that the reference hole of the inner layer circuit board is exposed from the side surface of the laminate, it is necessary to use a low-flow prepreg with little resin flow. Further, in order to prevent the flowed resin from reaching the reference hole, it is preferable that the inner layer circuit board is at least 1011 times longer than the prepreg.

[Embodiments of the invention] Next, the present invention will be explained by examples.

Example 1 520 +nx 330 nuex 0, 41m (7
) A reference hole 2 is made at the end of the double-sided flint board, and the inner layer circuit 3 is used to align the reference hole 2 during exposure.
was formed to obtain an inner layer circuit board 1. Next, six of these inner layer circuit boards 1 were arranged as shown in FIG. 1, both sides of which were sandwiched between prepregs 4 of 1050 ms x 105105 O as shown in FIG. 2, and a copper foil 5 was placed on the outermost layer. At this time, the reference hole 2 provided in the inner layer circuit board is arranged so as to come out to the outside of the prepreg 4. Next, this laminate was sandwiched between stainless steel plates and molded under heat and pressure to produce a four-layer printed circuit board 6.

Example 2 Using the 41II printed circuit board obtained in Example 1, a six-layer printed circuit board was manufactured in the following manner.

A four-layer printed circuit board was processed into a panel size leaving a reference hole, and a liquid resist was applied to the outer layer using the rotary printing method using the reference hole, and then etched to form a circuit. Next, this 411 circuit board was sandwiched between prepregs, copper foil was placed on the outermost layer, and integrally molded in the same manner as in Example 1 to produce a 6-layer printed board.

Example 3 A four-layer printed circuit board manufactured by the method of Example 1 was processed into a panel size with reference holes left, and then using the reference holes, a bale with liquid resist applied to the outer layer by rotary printing was etched. A circuit was formed only on one side. Next, the 471 printed circuit board 7 with the circuit formed on one side is attached to the third
As shown in the figure, stack two sheets with the circuit-formed surface facing inside, sandwiching the prepreg 16 between them, and use each reference hole 8 as a fixed guide hole to drill a hole to prevent positional shift.
An 8wIJ printed circuit board 1o was manufactured by erecting a bottle 9 for preventing displacement and integrally molding the board.

Example 4 520 +an+x 330 mg+x 0 , 1 m
When forming a circuit on the inner layer material of s+, the reference hole was used as a guide hole when passing a polishing line and a developing-etching-peeling line. Conventionally, the inner layer material was as thin as 0.1 ms, and there was a limit to its use due to the occurrence of entanglement in the line. - By using this method, it was possible to flow more smoothly than with a belt with a head for transfer. - Example 5 600 vs x 500 + m x 0 Two sheets were prepared in which four reference holes were provided in the .3ms inner layer material and inner layer circuits were formed. Next, as shown in FIG. 4, these inner layer circuit boards 11
After sandwiching the prepreg 12 on both sides and placing the copper foil 13 on the outermost layer, the reference holes 14 of each inner layer circuit board 11 are fixed with pins, and the inner layer circuit board 11 is sandwiched between stainless steel plates while preventing misalignment, and heated and press-formed. A six-layer printed circuit board 15 was manufactured.

[Effects of the Invention] As explained above, according to the present invention, since the inner layer circuit board is provided with a reference hole in its exposed portion, the reference hole can be used to form a circuit in a multilayer printed circuit board manufacturing model. It can be done easily.

Furthermore, the multilayer printed circuit board of the present invention can be used for a variety of purposes, such as being able to be used as a fixing guide hole to prevent misalignment when two or more boards are laminated to produce a multilayer printed circuit board. In the case of multilayer molding, there is no need to expose the reference hole each time, and there is an advantage that the reference hole once created can be used up to the final process depending on the purpose.

[Brief explanation of the drawing]

Fig. 1 is a plan view conceptually showing a 4-layer printed circuit board which is an embodiment of the present invention, Fig. 2 is a sectional view thereof, and Fig. 3 is an 8-layer printed circuit board which is another embodiment of the present invention. FIG. 4 is a cross-sectional view conceptually showing a six-layer printed circuit board which is still another embodiment of the present invention. 1.11... Inner layer circuit board 2.8.14... Reference hole 3... Inner layer circuit 4.12.16... Prepreg 5.13... Copper Foil 6.7...4ff Printed circuit board 9...
Misalignment prevention bin 10... 8-layer printed circuit board 15... 6-layer printed circuit board Applicant: Toshiba Chemical Co., Ltd. Representative Patent Attorney
Satoshi Suyama - Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] (1) In a multilayer printed circuit board having at least one inner layer circuit board with prepreg arranged on both sides, a portion of each inner layer circuit board is exposed on the side surface of the multilayer printed circuit board, and the exposed portion is A multilayer printed circuit board characterized in that at least one reference hole is provided in each inner layer circuit board.