JPH0714108B2 - Multilayer wiring board and manufacturing method thereof - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a multi-layer circuit board for mounting LSI used in a computer of the present invention, and more particularly to a thin film multi-layer circuit board having an insulating layer formed of an organic material.

BACKGROUND OF THE INVENTION The use of an organic insulating layer in order to achieve high precision and high functionality of a multilayer circuit board has hitherto been disclosed in, for example, JP-A-57-20.
No. 2797. Although the above-mentioned publication describes the lamination method using polyimide for the organic insulating layer, it does not describe the consideration of the reliability in the usage state of the multilayer substrate using the same. In other words, the main application of multi-layer circuit boards that require high precision and high functionality is the multi-layer circuit board for LSI mounting on large computers.
In this case, it is a major premise to hermetically seal the LSI mounting part from the viewpoint of reliability. The reason for this is that when the insulating layer is formed, a force that tends to separate between the insulating body and the organic insulating layer due to the stress generated by the difference in thermal expansion acts between them. This force is maximum at the edge of the substrate, and becomes larger as the organic insulating layer is thicker. Therefore, the thickness of the film is limited by itself. On the other hand, in the configuration described in the above publication, it is difficult to seal the airtightness with a force capable of counteracting the above force, because the end portion of the substrate includes an organic layer having poor moisture resistance. If the airtight sealing is dared, the back surface of the substrate must be used as an airtight sealing allowance, which may complicate the configuration.

[Object of the Invention] The present invention solves the above-mentioned problems of the prior art and provides a multi-layer wiring board capable of high precision and high performance in which airtight sealing is easy. It is to provide a multilayer wiring board that can be manufactured.

[Outline of the Invention] In the multilayer wiring board of the present invention, of each insulating layer, the periphery of the upper insulating layer covers the periphery of the lower insulating layer and is spaced apart from the peripheral edge of the insulating substrate. It is characterized in that it is configured to be located inside.

In the method for manufacturing a multilayer wiring board of the present invention, A) a first insulating layer is formed on one surface of the insulating substrate leaving a constant distance from the peripheral edge of the substrate, and B) the first insulating layer. C) after forming a conductor layer at a predetermined position on the exposed surface of the insulating substrate and the first insulating layer and the wiring layer, leaving a constant distance from the peripheral edge of the substrate and the first insulating layer. And a conductor layer is formed at a predetermined position on the second insulating layer so as to cover the periphery of the above, and D) and C) are similarly repeated a predetermined number of times, and each upper layer is formed. The insulating layer is formed so as to cover the surroundings of the lower insulating layer and to be located inside the insulating substrate at a distance from the peripheral edge of the insulating substrate.

Embodiments of the Invention Hereinafter, drawings showing embodiments of the present invention will be described. FIG. 1 is a manufacturing process diagram of a thin film multilayer wiring board showing an embodiment of the present invention. As shown in FIG. 3A, an insulating substrate such as an alumina ceramic plate or a thick film multilayer wiring board 1 is used.
For example, PIC (trade name) manufactured by Hitachi Chemical Co., Ltd. is uniformly applied to the entire upper surface by a spinner, and this is heat-treated to form a polyimide layer 20 of an organic insulating layer. After that, an etching mask 3 is formed using a photoresist. At this time, a mask opening 40 is formed at the through-hole forming portion, and the photoresist in a region at a constant distance 50 from the peripheral edge of the thick film multilayer wiring board 1 is removed. Then, as shown in FIG. 2B, the polyimide layer 20 is etched by using the etching mask 3 with a mixed solution of hydrazine hydrate and ethylenediamine or 02 plasma to remove the resist. Then, as shown in FIG. 3C, after forming the wiring layer 6 by film formation of a wiring material and photo-etching by a method used for semiconductors or the like, the same polyimide layer 21 as the polyimide layer 20 is formed into the thick film multilayer wiring. The polyimide layer 20 and the wiring layer 6 are formed so as to cover a region at a constant distance 50 from the peripheral edge of the plate 1. Then, the polyimide layer 21 is patterned as shown in FIG. At this time, the polyimide layer 21 in a region of a constant distance 51 from the peripheral edge of the thick film multilayer wiring board 1 is removed, and a mask opening 41 connecting to the wiring layer 6 is formed. Then, as shown in FIG. 8E, the above is repeated a required number of times to form a predetermined multilayer wiring board. At this time, the distance from the peripheral edge of the thick film multilayer wiring board 1 to the lowermost outer peripheral portion of the polyimide layer, that is, the distance 5x to the outer peripheral portion of the uppermost polyimide layer is the peripheral edge of the thick film multilayer wiring board 1. It is necessary to consider so that the distance is smaller than 5 (x-1) to the innermost portion of the lowermost portion of the polyimide layer 21 and does not become zero.

Thus, in the present invention, among the plurality of polyimide layers stacked on the thick film multilayer wiring board 1, the upper polyimide layer covers the periphery of the lower polyimide layer and the thick film multilayer wiring board 1 The multilayer wiring board is configured to be positioned on the inner side with a distance 5x left from the peripheral edge. As a result, the peripheral edge of each polyimide layer uniformly adheres to the thick film multilayer wiring board 1 and the film thickness becomes substantially constant, so that the peeling force of the polyimide layer from the thick film multilayer wiring board 1 increases. Not only can it be prevented, but also the polyimide layer can be prevented from peeling off. Therefore, stable, high-performance, and high reliability can be obtained. Therefore, since the peripheral end portion of the thick film multilayer wiring board 1 serves as an airtight sealing margin, the structure does not become complicated.

The upper polyimide layer 21 that covers the lower polyimide layer 20 is formed such that the thickness of the peripheral edge portion thereof is smaller than the thickness of each polyimide layer in the stacking direction of the thick film multilayer wiring board 1. Further, it is possible to prevent the peeling force of the polyimide layer from increasing, which is more effective.

Further, in the manufacturing method of the present invention, as described above, the first-layer polyimide layer 21 is formed on the thick-film multilayer wiring board 1 leaving a constant distance 50 from its peripheral edge, and then the predetermined polyimide layer is formed. A wiring layer 6 is formed at a position, and a constant distance 51 from the peripheral edge of the thick film multilayer wiring board 1 on the exposed surface of the thick film multilayer wiring board 1, the first polyimide layer and the wiring layer.
To form the second polyimide layer 21 and the wiring layer 6, and then repeat the third and subsequent polyimide layers and the wiring layer in the same manner, so that the peripheral edge portion of the upper polyimide layer is Since it is formed so as to cover the periphery of the lower polyimide layer and to be located inside at a distance 5x from the peripheral edge of the thick film multilayer wiring board 1, it is possible to reliably manufacture the multilayer wiring board.

As described above, according to the present invention, among the insulating layers,
The upper insulating layer covers the surrounding lower insulating layer,
Also, the insulating film is positioned inside the insulating substrate at a distance from the peripheral end, and the film thickness at the peripheral end of each insulating layer is uniformly adhered to the insulating substrate.
Since the film thickness is configured to be constant, not only the peeling force of the insulating layer from the insulating substrate is prevented from increasing, but
As a result of preventing the insulating layer from peeling off from the insulating substrate, there is an effect that stable and high function and high reliability can be obtained.

Further, according to the method of the present invention, a first-layer insulating layer is formed on one surface of the insulating substrate leaving a constant distance from the peripheral edge of the substrate, and then a conductor layer is formed at a predetermined position of the first-layer insulating layer. After the formation, the insulating substrate of the first layer, the insulating layer of the first layer, and the wiring layer, on the exposed surface, leaving a certain distance from the peripheral edge of the substrate and covering the periphery of the first insulating layer, the second layer. Along with forming an insulating layer, a conductor layer is formed at a predetermined position of the second insulating layer, and thereafter, an insulating layer and a conductor layer are repeatedly formed a predetermined number of times on these exposed surfaces, Since each upper insulating layer is formed so as to cover the periphery of the lower insulating layer and be located inside at a distance from the peripheral edge of the insulating substrate, it is possible to reliably manufacture the multilayer wiring board. There is an effect to say.

[Brief description of drawings]

1 (a) to 1 (e) are manufacturing process diagrams of a multilayer wiring 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 (4)

[Claims] 1. In a multilayer wiring board formed by alternately stacking an insulating layer made of an organic material and a conductor layer on an insulating substrate, the peripheral end portion of the upper insulating layer of each insulating layer is A multilayer wiring board formed so as to cover the periphery of a lower insulating layer and be located inside the insulating substrate at a distance from the peripheral edge of the insulating substrate. 2. The thickness of the peripheral edge portion of the upper insulating layer covering the lower insulating layer is smaller than the thickness of each insulating layer stacked on the insulating substrate in the stacking direction. The multilayer wiring board according to claim 1. 3. A multilayer wiring board formed by alternately stacking an insulating layer made of an organic material and a conductor layer on an insulating substrate, wherein A) one surface of the insulating substrate is fixed from a peripheral edge of the substrate. After forming a first insulating layer with a distance left between them, B) and then forming a conductor layer at a predetermined position on the first insulating layer, and C) exposing the insulating substrate and the first insulating layer and wiring layer. A second insulating layer is formed on the surface where the second insulating layer is provided, leaving a certain distance from the peripheral edge of the substrate and covering the periphery of the first insulating layer, and a conductor is provided at a predetermined position of the second insulating layer. Layers are formed, and D) and C) are repeated a predetermined number of times in the same manner, and the peripheral edge of each upper insulating layer covers the periphery of the insulating layer below it and is separated from the peripheral edge of the insulating substrate. A method for manufacturing a multi-layer wiring board, characterized in that it is formed so as to be positioned inside the board with a space therebetween. 4. The thickness of the peripheral edge portion of the second or more insulating layers is thinner than the thickness of each insulating layer stacked on the insulating substrate in the stacking direction. A method for manufacturing a multilayer wiring board according to claim 3.