JPS6224694A - Multilayer 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 [Field of Application of the Invention] The present invention relates to a multilayer circuit board for mounting an LSI used in electronic computers and the like, and particularly to a thin film multilayer circuit board in which an insulating layer is formed of an organic material.

[Background of the invention]

Conventionally, the use of organic insulating layers to improve the precision and functionality of multilayer circuit boards has been proposed, for example, in Japanese Patent Application Laid-Open No.
It is described in No. 202797. Although the above-mentioned publication describes a method of laminating the organic insulating layer using polyimide, it does not describe any consideration of the reliability of the multilayer substrate using this in the usage conditions. In other words, the main application of multilayer circuit boards that require high precision and high functionality is multilayer circuit boards for mounting LSIs in large computers. The main premise is to stop. The reason is that when forming the insulating layer,
Due to the stress generated between the insulating object and the organic insulating layer due to the difference in thermal expansion, a force that tends to separate them acts between them. This force is maximum at the edge of the substrate, and increases as the thickness of the organic insulating layer increases. This is because the thickness of the film is subject to its own limitations. On the other hand, in the configuration described in the above-mentioned publication, since an organic layer with poor moisture resistance is included at the edge of the substrate, it is difficult to achieve an airtight seal with a force that can counteract the above-mentioned force. If airtight sealing is to be performed, the back side of the substrate must be made into an airtight sealing area, which may complicate the configuration.

[Purpose of the invention]

The present invention solves the above-mentioned conventional problems and provides a multilayer circuit board that can be easily hermetically sealed, has high precision, and is highly functional.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that insulating layers and conductor layers are alternately laminated on a portion other than the peripheral portion of the upper surface of the insulating portion base, and the peripheral portion is formed into an airtight sealing area. It is.

[Embodiments of the invention]

The drawings showing embodiments of the present invention will be described below. 1st
The figure is a manufacturing process diagram of a thin film multilayer circuit board showing an embodiment of the present invention. As shown in the same figure (al), for example, BIQ (PIQ) manufactured by Hitachi Chemical Co., Ltd.
(trade name) is uniformly applied using a spinner and heat-treated to form a polyimide layer 20 as an organic insulating layer. Thereafter, an etching mask 3 is formed using photoresist. At this time, a mask opening 40 is formed at the location where the through hole is to be formed, and the photoresist is removed from an area a certain distance 50 from the peripheral edge of the thick film multilayer wiring board 1. Then, as shown in FIG. 3B, using the etching mask 3, the polyimide N20 is etched with a mixture of hydrazine hydrogen hydride and ethylenediamine, or with 02 plasma, to remove the resist. Next, the same figure (C
As shown in 1, wiring material is formed by a method used in semiconductors.

After forming the wiring layer 6 by photo-etching, polyimide 1!21, which is the same as the polyimide layer 20, is coated in an area a certain distance 50 from the peripheral edge of the thick film multilayer wiring board l.

It is formed to cover the polyimide layer 20 and the wiring layer 6. Then, as shown in FIG. 2(d), the polyimide layer 21
Buttering. At this time, the thick film multilayer wiring board 1
A portion of the polyimide layer 21 at a certain distance 51 from the peripheral edge of the polyimide layer 21 is removed, and a mask opening 41 connected to the wiring layer 6 is formed. Then, as shown in FIG. 2(e), the above steps are repeated a necessary number of times to form a predetermined multilayer circuit board. At this time, the polyimide layer 21 is
The distance 5x to the bottom outer circumference of the thick film multilayer wiring board 1 is
It is necessary to take care that the distance 5 from the peripheral edge of the polyimide layer 21 to the lowermost inner peripheral part of the polyimide layer 21 is smaller than X-11 and does not become O.

Therefore, in the present invention, a region is formed in stages at a predetermined distance from the peripheral edge of the thick film multilayer wiring board 1, and the region is configured so as not to contain an organic layer, so that it is difficult to increase the number of layers. Even if the film thickness is kept constant, the peeling force can be prevented from increasing, and a stable, highly functional, and highly reliable multilayer circuit board can be realized.

(Effects of the Invention) As described above, the present invention maintains a constant film thickness even when multilayered, thereby preventing an increase in peeling force and realizing a stable, highly functional, and highly reliable multilayer circuit board. It has the effect of being able to.

[Brief explanation of drawings]

FIGS. 1(a) to 1(e) are manufacturing process diagrams of a multilayer circuit board showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Thick film multilayer wiring board, 21.22... Polyimide layer, 3... Etching mask, 40.41... Mask opening, 50, 51... Insulating layer removal area, 6...・
wiring layer.

Claims (1)

[Claims] 1. In a multilayer wiring board formed by alternately stacking an insulating layer made of an organic substance and a conductor layer on an insulating substrate, a certain distance area at the peripheral end of the insulating substrate A multilayer wiring board characterized in that an insulating layer made of an organic substance is formed by leaving the . 2. The insulating layer is configured such that its total thickness (the sum of the thicknesses of each layer) becomes thinner toward the periphery of the base at the periphery of the insulating layer. The multilayer wiring board described.