JPH0298195A - Manufacture of multilayer printed board - Google Patents

Abstract

PURPOSE:To form an accurate printed board without positional deviation between cores at the time of press-molding by aligning the cores with a shape memory alloy pin of a predetermined shape. CONSTITUTION:A shape memory alloy pin 1 formed at one end with a collar 1a and at the other with a divided part 1b is inserted into the positioning hole of a core material 4 superposed through a prepreg 3, the material 4 is positioned, pressurized, heated and press-molded. Then, the part 1b of the pin 1 is deformed by heating, the whole length of the pin 1 is decreased to be molded without buckling, etc., to eliminate the positional deviation between the materials 4, and an accurate multilayer printed board is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to the molding of multilayer printed circuit boards.

[Conventional technology]

Conventionally, when molding a multilayer printed circuit board, the process shown in Fig. 2(a)
As shown in 2. Prepreg (adhesive sheet) 3.
The core materials 4 were stacked one on top of the other, and 11 positioning pins made of materials such as copper or aluminum were passed through the positioning holes of the core materials 4 to fix the inner layer core materials.

[Problem to be solved by the invention]

However, with conventional positioning pins, as shown in Figure 2 (b), when the plate thickness becomes thinner due to resin leakage from the prepreg during press molding, the pins buckle and the positional grain size between the core materials deteriorates. was there.

This invention was made to solve the above-mentioned problems, and provides a method for manufacturing a multilayer printed circuit board that can produce a multilayer printed circuit board with high grain size and no misalignment between cores during press molding. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the present invention fixes the inner layer core material in a predetermined position using a positioning pin made of a shape memory alloy. The shape is memorized so that it can be bent to a predetermined thickness.

Specifically, the method for manufacturing a multilayer printed circuit board includes a final step.

In other words, shape memory is created by dividing one or both ends into at least two or more parts in the positioning holes of multiple core materials stacked with prepreg in between, and giving the property that the tip expands from the divided part at a predetermined temperature or higher. The method includes a step of positioning the plurality of core materials by penetrating the alloy pin, and a step of heating the core material that has passed through the step above the predetermined temperature and pressurizing it.

[Effect]

According to the above configuration, the shape memory alloy pin is deformed when heated and pressurized to maintain the inner layer core material at a predetermined thickness, and
The shape memory alloy pin located between the inner layer core materials that has reached the predetermined 17 is shortened between them, that is, the shape memory alloy pin is not deformed because no force is applied to it, and therefore the shape memory alloy pin located between the inner layer core materials is shortened. positional shift is prevented.

〔Example〕

This invention will be explained below with reference to Examples.

FIGS. 1(a) to 1(d) show an embodiment of the present invention.
An explanatory diagram of the process of manufacturing method J of a multilayer printed circuit board, (a
) and (b) show before press molding, and (c) and (d) show after press molding.

In FIGS. 1(a) and (b), 1 is a shape memory alloy pin, one end of which is provided with a collar 1a, and the other end of which is provided with a divided portion 1b that is divided into two. A characteristic is given that the tip becomes wider than this divided portion 1b. Further, 2 is a copper foil, 3 is a prepreg, and 4 is a core material, which are laminated in a predetermined order, and the shape memory alloy pin is passed through the positioning hole of the core material.

When heated and pressurized in this state, the image shown in Fig. 1 (C) is obtained.

As shown in (d), the divided portion 1b of the pin 1 is deformed when the temperature exceeds a predetermined shape memory temperature, and the tip becomes wider than the divided portion 1b, and the distance between this wide portion and the collar Ia becomes a predetermined distance. Since the total length of the pin is reduced, no logic problems occur, and no positional distortion occurs between the core materials.

The positioning of multiple pieces of core material may be done either by penetrating the pins with the core materials and prepregs stacked one on top of the other, or by sequentially pricking the core materials and prepregs through the pins and stacking them. The portion may be provided not only at one end of the pin but also at both ends.

(Effects of the Invention) As explained above, according to the present invention, even if the thickness of the prepreg is reduced due to resin flow during press molding,
The positioning pins are deformed and the tightening distance is reduced and the total length is shortened, so each layer is molded in the correct position without any logic, so it is possible to create a multi-layer structure with high rust resistance without misalignment between the core materials. Printed circuit boards can be obtained.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are diagrams explaining the steps of an embodiment of the present invention, and FIGS. 2(a) and (b) are diagrams explaining the steps of a conventional example. In the figure, 1 is a shape memory alloy pin, 1a is a collar, ib is a divided portion, 3 is a prepreg, and 4 is a core material. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] Made of a shape memory alloy that divides one or both ends into at least two or more parts in the positioning holes of multiple core materials stacked with prepreg sandwiched in between, giving the tip the property of expanding from this divided part at a certain temperature or higher. A method for manufacturing a multilayer printed circuit board, comprising the steps of: positioning the plurality of core materials by penetrating the pins; and heating the material that has passed through the step above the predetermined temperature and pressurizing it. .