JPS61117884A - Multilayer printed wiring board - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field J] The present invention relates to a multilayer printed wiring board substrate with excellent drillability.

[Background technology] Conventionally, in manufacturing substrates used for multilayer printed wiring boards, metallic foil such as @ foil is coated on both sides of prepreg, which is formed by impregnating lath woven cloth with epoxy resin and drying it.
A laminate is created by layering the laminate, and then metal foil is loaded and pressed on both sides of the laminate via a prepreg having the same structure as above to create a substrate for a multilayer printed wiring board.
In this way, conventional boards use lath woven fabric as the prepreg base material, which has the disadvantage of poor drilling performance for through-holes, which shortens the useful life of the drill bit. Moreover, productivity was poor due to the poor drilling performance of the drill.

[Object of the Invention] The present invention has been made in consideration of the above α, and provides a multilayer printed wiring that can extend the life of a drill blade, increase productivity, and reduce costs. The purpose of the company is to provide a board substrate.

[Disclosure 1 of the Invention That is, the multilayer printed wiring board substrate of the present invention includes a laminate 3 in which metal foils 2.2 are laminated and molded on both sides of an inner layer core material 1.
It is characterized by laminating an outer layer material 8 on both sides of which a metal M7 is provided via an insulating layer 4 whose base material is a nonwoven fabric impregnated with resin. The above objective was achieved by using .

The present invention will be explained in detail below. The non-woven fabric used for the base material of the insulating layer 4 includes non-FM fibers such as glass and asbestos, synthetic resin fibers such as polyamide and polyester,
Fabrics, non-woven fabrics, or mats made of natural fibers such as paper alone or in a blend, and also include those in which fibers are bonded with synthetic resin binder and those that utilize the entanglement of fibers. Further, as the resin for the insulating layer 4, epoxy resin, polyimide, etc. can be used, and these resins can be used alone or in combination with an inorganic filler.

The nonwoven fabric base material is impregnated with these resins and dried to form a prepreg 5, and this prepreg 5 is laminated and cured to form the insulating layer 4. In addition, as the inner layer core material 1, prepreg 5 based on the nonwoven fabric used above may be used, but usually a prepreg formed by impregnating a lath woven fabric with epoxy resin, etc. and drying it is used. It is from et al. A laminated board 3 is created by laminating gold R whistles 2 such as copper foil on both sides of this prepreg having lath woven fabric as a base material, and then circuits are formed on the front and back sides of the laminated board 3, as shown in FIG. As shown in the figure, outer layer material 8 provided with metal W7.7 such as copper foil is placed on both the front and back surfaces of the laminate 3 through the prepreg 5 for the insulating layer 4 created as described above, and heated. A substrate for a multilayer printed wiring board is obtained by pressure molding. The prepreg 5 for the M green layer may be formed by laminating a plurality of layers, and in this case, a prepreg having a nonwoven fabric as a base material and a prepreg having a textile fabric as a base material may be used together.

Therefore, by using nonwoven fabric as the base material for the insulating layer 4, it is superior in drilling workability compared to an insulating layer formed using only woven fabric as a base material, and therefore, it is easier to drill for multilayer printed wiring board substrates. In addition to prolonging the life of the drilling blade, the roughness of the inner wall surface of the drill is improved (the unevenness of the inner wall surface is reduced), ensuring through-hole plating, and improving the inner layer connection of the through-hole section. This eliminates the occurrence of defects and improves the quality of the board. In addition, by using a nonwoven fabric as the base material of the insulating layer 4, the drilling processability of the substrate is good, which improves productivity and improves the productivity of the substrate. This is a great way to reduce costs.

Incidentally, even in the case of a multilayer printed wiring board substrate having a ratio of 3/1 or more, prepreg having a nonwoven fabric as a base material can be used for all the insulating layers 4.

The present invention will be specifically described below based on examples.

1. A 75 g/m2 plus nonwoven fabric was impregnated with epoxy fff fat varnish and dried to obtain a 700 g/m'' resin-impregnated prepreg.Meanwhile, 0.5 m thick ordinary glass was used as the inner layer fur material. Lay one sheet of the above prepreg on each side of the epoxy copper-clad laminate, and add 0.035 mm on the outside.
Layer copper foil of
Kg/cn+2, laminated for 100 minutes at a temperature of 170°C,
A four-layer multilayer printed wiring board substrate having a thickness of 1.4II+m was obtained.

Next, the heat resistance of the obtained wiring printed wiring board substrate and the amount of wear of the drill during drilling were measured. As a result, there were no abnormalities when soldering at 260℃ for 20 seconds and 70 seconds, and the amount of wear on the drill after drilling 1000 holes was 10%.
Met.

11 A 200 g/m'' lath woven fabric was impregnated with epoxy resin varnish and dried to obtain a 400 g/m'' resin-impregnated prepreg. On the other hand, as the inner layer fur material, two of the above prepregs were placed on both sides of the lath epoxy copper clad laminate with a thickness of 0.5a + so.
Stack the sheets one by one, and add 0.035IIIl on the outside.
Stack the foils and put them between the metal plates and apply a pressure of 40kg/c.
m2, laminated for 100 minutes at a temperature of 170°C to a thickness of 1.
A four-layer multilayer printed wiring board substrate of 411II was obtained.

Next, the heat resistance of the conventional multilayer printed wiring board substrate and the amount of wear of the drill during drilling were measured. As a result, the heat resistance was normal and the amount of drill wear was 15%.

[Effect of the invention]
1 As described above, the present invention has gold I1 on both sides of the inner fur material.
Since the outer layer material is laminated on both sides of the laminate board with 4 foils laminated through an insulating layer based on resin-impregnated nonwoven fabric, it is easy to use with a drill bit without reducing the heat resistance of the board. It is possible to extend the life of the product, improve productivity, and reduce manufacturing costs.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a schematic exploded cross-sectional view of an embodiment of the present invention and a cross-sectional view of a substrate for a multilayer printed wiring board, and FIG. 2 is a partially cutaway cross-sectional view of the same laminated board. 1 is an inner layer fur material, 2 is a metal foil, 3 is a laminate, 4 is an insulating layer, 7 is a metal foil, and 8 is an outer layer material. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 1! 2

Claims (1)

[Claims] (1) Metal foil is laminated on both sides of the inner core material, and outer layer material is laminated on both sides of the laminate with metal foil interposed therebetween, with an insulating layer made of resin-impregnated nonwoven fabric as the base material. A multilayer printed wiring board substrate characterized by: