JPH07221451A - Manufacture of multilayer wiring board with viahole - Google Patents

Abstract

PURPOSE:To enable manufacture of a multilayer wiring board with a viahole of high surface smoothness and little surface resin remainder by using a polyethylene sheet for making a pressure applied to a wiring board uniform during lamination bonding. CONSTITUTION:A desired circuit pattern is formed by boring an inner layer board 1 and by applying plating. Then, a bonding sheet 2 is held between a plurality of inner boards 1 wherein a circuit is formed. In the process, a mold release sheet 3, a polyethylene sheet 4 and a mold release sheet 3 are arranged one by one in an outside. They are held by a mirror plate, and are heated and pressurized for lamination bonding. In the process, the polyethylene sheet 4 melts. Therefore, a wiring board surface formed by the molten polyethylene sheet 4 is uniformly pressurized. It is thereby possible to stop resin from effusing to a viahole uniformly, to improve surface smoothness and to reduce surface resin remainder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electronic computer, a wireless device,
The present invention relates to a method for manufacturing a multilayer wiring board used for electric transmission equipment and the like.

[0002]

2. Description of the Related Art Generally, a multilayer wiring board with via holes which plays a role of electrical interlayer connection without inserting parts is plated with an inner layer board which is pre-drilled at a desired position to form a circuit, and an adhesive sheet. It is formed by stacking a plurality of the above-mentioned inner layer plates through the above, heating, pressurizing, and laminating and adhering.

When carrying out this laminated adhesion, the resin exuding from the adhesive sheet exudes from the previously drilled holes. It is particularly important in terms of quality and production yield to prevent the resin from seeping out. A method of placing a release sheet on the outer side of a wiring board and heating and pressurizing the resin is widely used when superposed to prevent the resin from oozing out.

[0004]

In a widely used method, the resin exuding through the holes deforms the release sheet. Therefore, the surface of the molded wiring board becomes uneven and remarkably deteriorates the surface smoothness. Further, there is a serious problem that the exuded resin adheres to the surface and remarkably hinders the outer layer circuit formation. The present invention provides a method for manufacturing a multilayer wiring board with via holes, which has high surface smoothness and less surface resin residue.

[0005]

[Means for Solving the Problems] When laminating and adhering by the conventional method, the cause of the resin exudation of the adhesive sheet to the via hole was considered to be large. It was found that the size became large and the surface of the molded wiring board was not smooth. Further, when the cause of the deformation of the release sheet was investigated, it was found that the resin exuding from the adhesive sheet extruded the release sheet. Furthermore, it was found that the pressure applied to the surface of the wiring board was non-uniform. Therefore, it was found that it is important to make the applied pressure uniform and reduce the deformation of the release sheet in order to reduce the resin oozing and enhance the surface smoothness. The present invention is characterized in that a polyethylene sheet is used in order to make the pressure applied to the wiring board uniform during the lamination and adhesion.

The present invention will be described with reference to FIG. Figure 2
An inner layer plate is prepared as shown in (a). Next, as shown in FIG. 2B, the inner layer plate is perforated. Next, as shown in FIG. 2C, plating is performed. Further, as shown in FIG. 2D, a desired circuit pattern is formed on the inner layer plate.

Next, as shown in FIG. 2 (e), the adhesive sheet is sandwiched between a plurality of circuit-formed inner layer plates. At this time, further, a release sheet, a polyethylene sheet, and a release sheet are sequentially arranged on the outside. This is sandwiched between end plates and heated and pressed to laminate and adhere. The heating and pressurizing means and conditions can be the same as in the conventional method. As a result, a multilayer wiring board with via holes can be manufactured.

[0008]

According to the present invention, the polyethylene sheet is melted when heating, pressurizing and laminating and adhering. Therefore, the surface of the wiring board formed by the melted polyethylene sheet is uniformly pressed. Therefore, it is possible to uniformly press the resin that is about to seep into the via hole, improve the surface smoothness, and reduce the surface resin residue.

[0009]

EXAMPLE A glass cloth epoxy resin copper-clad laminate MCL-E-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.) having a thickness of 0.2 mm was drilled. The perforated inner layer plate was plated to further form a circuit. Furthermore, a 0.1 mm glass cloth epoxy resin prepreg GE which is an adhesive sheet between the inner layer plate and another inner layer plate on which a circuit is formed.
-67N (trade name, manufactured by Hitachi Chemical Co., Ltd.) was inserted. Next, a release sheet having a thickness of 28 μm Tedra sheet 100SM30SR (manufactured by Somal Co., Ltd., trade name), a thickness of 40 μm polyethylene sheet (produced by Toshin Chemical Co., Ltd., trade name), and a 28 μm tedra sheet are sequentially provided on both outer sides of the inner layer plate. I arranged it. This was thermocompression bonded for 90 minutes at a molding temperature of 170 ° C. and a forming pressure of 3.9 MPa to obtain a wiring board with a 4-layer via hole having a board thickness of 0.5 mm. The surface smoothness of the examples according to the present invention is shown in Table 1 in comparison with the conventional method.

[0010]

[Table 1]

[0011]

When the method of the present invention is used, high smoothness of the surface is obtained.

[Brief description of drawings]

1A to 1E are cross-sectional views showing a manufacturing process of the present invention.

2A to 2E are cross-sectional views showing a manufacturing process of a conventional example.

[Explanation of symbols]

 1 Inner layer board 2 Adhesive sheet 3 Release sheet 4 Polyethylene sheet

Claims (1)

[Claims] 1. A method for manufacturing a multilayer wiring board with a via hole, which comprises laminating a plurality of inner layer boards, which have been through-hole drilled in advance, plated, and formed a circuit, via an adhesive sheet, and laminated and bonded. A method for manufacturing a multilayer wiring board with a via hole, which comprises using a polyethylene sheet when stacking inner layer boards.