JPH0680896B2 - Multilayer printed board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A multilayer printed board according to the present invention has a positioning reference hole formed on a prepreg, which is made to correspond to a weave direction of a woven fabric forming the prepreg. It is characterized in that the strain generated during lamination is reduced.

[Industrial application field]

The present invention relates to an improvement in the structure of a multilayer printed board, and more particularly to a multilayer printed board with reduced strain when laminating a prepreg board.

[Conventional technology]

FIG. 4 is a perspective view of an essential part showing the structure of a conventional multilayer printed board.

As shown in FIG. 4, the multilayer printed board is composed of a pair of upper and lower surface layer materials 2, and at least one or more prepregs 4 and intermediate layer materials 3. The prepreg 4 is provided between the intermediate layer material 3 and the surface layer material 2 or the intermediate layer material 3
It is well known that the bonding material provided between the intermediate layer material 3 and the intermediate layer material 3 is obtained by impregnating the woven cloth 4a having glass fiber or paper fiber as a base material with an adhesive.

The stacking process of the multilayer printed board will be described below with reference to FIG.

． On the guide pins 1 set up on the support base 10, the surface layer material
2, the prepreg 4, and the circular reference hole 6 of the intermediate layer material 3 are sequentially inserted to perform the respective positioning.

． When the positioning is completed, the multilayer printed board base material (tentative name) is sent to a hot press device (not shown), where it is pressed from above and below and heated to form a multilayer printed board.

[Problems to be solved by the invention]

However, the shrinkage rate of the woven fabric 4a that constitutes the prepreg during lamination in the warp direction (arrow AA 'direction) is much larger than that of the surface layer material 2 and the intermediate layer material 3,
At the time of stacking, the contraction stress acts on the circular reference holes 6 of the surface layer material 2 and the intermediate layer material 3 via the guide pins 1,
Distortion occurs in the multilayer printed board.

[Means for solving problems]

In the multilayer printed board of the present invention, the guide pin 1 is fitted in the central pair of the three pairs of reference holes of the prepreg 4 arranged between the surface layer material 2 and the intermediate layer material 3 as in the conventional case. The circular reference hole 6 inserted in the mating state is left as it is, and the other two pairs of reference holes formed at both ends in the longitudinal direction (arrow AA ′) of the standard size of the multilayer printed board, that is, the warp direction are the weft direction. The deformation reference hole 7 is longer in the warp direction than in the (arrow BB 'direction).

[Action]

In the multilayer printed board constructed in this way, the guide pin 1 does not substantially move due to the action of the deformation reference hole 7 even when the woven cloth 4a contracts, and therefore the surface layer material 2 and the intermediate layer material 3 The influence of the shrinkage stress of the prepreg 4 on the prepreg 4 is reduced.

Therefore, when the present invention is applied, the distortion of the multilayer printed board during lamination is significantly reduced.

〔Example〕

 The present invention will be described in detail below with reference to the accompanying drawings.

FIGS. 1 (a) and 1 (b) are a perspective view and a partially enlarged view of an essential part showing an embodiment of the multilayer printed board according to the present invention.
The same parts as those in the figure are designated by the same reference numerals.

The multilayer printed board of the present invention is shown in FIGS. 1 (a) and 1 (b).
As shown in FIG. 3, three pairs (6
Of the standard holes, only one pair in the central portion is the circular standard hole 6 having the diameter d as in the conventional case, but the other two pairs of standard holes formed at both ends are in the warp direction of the prepreg 4. (Arrow
The deformation reference hole 7 has a dimension of d + α whose dimension in the AA ′ direction is larger than dimension d in the weft direction (arrow BB ′ direction).

Therefore, as shown in the partially enlarged view of FIG. 1 (b), even if the prepreg 4 contracts in the direction of arrow AA 'during stacking, the guide pin 1 moves in the deformation reference hole 7 in the direction of arrow AA'. Since the shrinkage stress is absorbed by the shrinkage, the stress does not act on the circular reference holes 6 of the surface layer material 2 and the intermediate layer material 3 during stacking.

FIG. 2 is a plan view showing an embodiment of the prepreg structure.

As shown in FIG. 2, the deformation reference hole 7 formed in the prepreg 4 has a dimension d + α in the longitudinal direction of the standard size of the multilayer printed board, that is, in the warp direction (arrow AA ′ direction) of the woven fabric 4a. , Is formed in a rectangular shape longer than the dimension d in the weft thread direction (arrow BB 'direction) (the dimension in the weft thread direction, that is, the arrow BB' direction is the same as the diameter d of the circular reference hole 6).

FIG. 3 is a plan view of an essential part showing a modification of the prepreg structure. In the case of this modification, the deformation reference hole 7 is an oval reference hole 7a of an oval shape.

〔The invention's effect〕

By applying the present invention, the problem of distortion of the multilayer printed board due to the shrinkage of the prepreg is solved, so that the workability in manufacturing the multilayer printed board and the reliability of the product are significantly improved.

[Brief description of drawings]

1 (a) and 1 (b) are perspective views and a partially enlarged view of an essential part showing an embodiment of a multilayer printed board of the present invention, and FIG. 2 is a plan view showing an embodiment of a prepreg structure, and FIG. FIG. 4 is a plan view of relevant parts showing a modified example of the prepreg structure, and FIG. 4 is a perspective view of relevant parts showing the structure of a conventional multilayer printed board. In the figure, 1 is a guide pin, 2 is a surface layer material, 3 is an intermediate layer material, 4 is a prepreg, 4a is a woven cloth, 6 is a circular reference hole, 7 is a deformation reference hole, and 7a is an oval reference hole. Show.

Claims (1)

[Claims] 1. A reference hole is provided in each of a surface layer material (2), an intermediate layer material (3), and a prepreg (4) interposed therebetween, and a guide pin (1) is inserted into the reference hole. In the structure of a multilayer printed board for performing relative position determination by aligning the warp direction of the woven fabric (4a) constituting the prepreg (4) with the longitudinal direction of the standard size of the multilayer printed board, 4) Of the total of 3 pairs of reference holes formed at the center and both ends in the longitudinal direction, the pair of reference holes at the center insert the guide pin (1) in a fitted state. A multilayer printed board characterized in that it is a circular reference hole (6), and the two pairs of reference holes formed at both ends are deformation reference holes (7) whose dimension in the warp direction is longer than that in the weft direction.