JPH04142794A - Ceramic multilayer wiring board - Google Patents

Abstract

PURPOSE:To protect a ceramic multilayer wiring board against cracks induced by stress and to prevent the end of the board from being protuberant by a method wherein grooves are provided to all the laminated surface of a multilayer wiring board, and the edge of a laminated organic resin layer is positioned in the groove. CONSTITUTION:Grooves 12 and 14 are provided in lattice at a certain interval onto all the laminated surface of a ceramic multilayer wiring board 11. An organic resin layer 13 of polyimide is laminated on the board 11 so as to enable its sides to be coincident with the outermost grooves 12. The grooves 12 and 14 are formed 1-10mm and 10mum-1mm in width and depth respectively and provided in lattice at an interval of 10-20mm onto all the surface of the ceramic multilayer wiring board 11. At this point, the outermost groove 12 where the end face of the laminated polyimide layer 13 is set is formed larger than the other inner grooves 14 in both width and depth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic multilayer wiring board, and particularly to the structure of a ceramic multilayer wiring board in which an organic resin is laminated on the surface.

[Conventional technology]

Conventionally, the surface of this type of ceramic multilayer wiring board has not been subjected to any processing to increase the adhesion strength with the organic resin layer, and only an adhesion improver is applied before applying the organic resin varnish. Ta.

[Problem to be solved by the invention]

In the conventional ceramic multilayer wiring board described above, when an organic resin layer is formed on the surface of the board, the adhesion strength between the board and the organic resin film is insufficient, and as the organic resin film becomes multilayered, the edges There have been disadvantages in that the organic resin may peel off from the substrate and the ceramic substrate may crack or break due to the concentrated residual stress in the organic resin layer.

Furthermore, when an organic resin is applied to a substrate using a spin cord, bulges inevitably occur at the edges, resulting in poor removal of peer holes in the organic resin layer at the periphery.

[Means to solve the problem]

The ceramic multilayer wiring board of the present invention includes a ceramic multilayer board having a conductor layer inside, a groove formed on the entire laminated surface of the ceramic multilayer board, and a groove formed on the surface of the ceramic multilayer board, the edge of which is formed on the surface of the board. and an organic resin layer formed within the groove on the outermost periphery of the top.

Further, in the ceramic multilayer wiring board of the present invention, the grooves are formed in a lattice shape, and the outermost groove is formed to be larger in width and depth than the other grooves, and the The resin layer is made of polyimide.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1 and 2 are a sectional view and a plan view of a first embodiment of the present invention.

As shown in the figure, grid-like edges 12.degree. 14 are formed at certain intervals over the entire laminated surface of the ceramic multilayer wiring board 11. The end face of the organic resin layer 13, in this example polyimide, laminated on the substrate is aligned with the outer periphery of the groove 12 formed at the outermost periphery.

These 12. ．． 14 is formed by processing the green sheet laminate before firing in the process of forming the ceramic multilayer wiring board. This is because it is easier to process the green sheet laminate, but with this method, the edges may be formed deviating from the desired position due to differences in the shrinkage rate of the laminate after firing. Therefore, if accurate grooves are to be formed, processing can be performed after firing.

The size range of Wei 12.14 is 1mm to 10m in width.
m, depth is about 10 μm to 1 mm, approximately 10 m
They are formed in a lattice pattern over the entire surface of the ceramic multilayer wiring board at a pitch of m to 20 mm. At this time, only the outermost groove 12, in which the end face of the polyimide layer 13 to be laminated is located, is formed to have a larger width and depth than the groove 14 inside the substrate.

Next, the results obtained by adopting the structure of the first embodiment as shown in FIG. 1 will be described below.

First, the adhesion strength between the ceramic multilayer wiring board 11 and the polyimide layer 13 will be described. Ceramic multilayer wiring board 1
By forming the grooves 12 and 14 over the entire surface of the polyimide layer 13, the contact area between the polyimide layer 13 and the ceramic multilayer wiring board 11 becomes substantially larger, and the mutual adhesion strength can be increased. - As an example, 160mmX160
This figure shows the effect when polyimide is simply laminated on a glass ceramic multilayer wiring board with relatively low strength of mm. Hereinafter, the glass ceramic multilayer wiring board will be abbreviated as GCS in the description. When polyimide is simply laminated on GC3 with no processing applied to the laminated surface, the polyimide layer peels off from the edge after a film thickness of about 200 μm, or the GCS under the edge of the polyimide layer cracks. Occur.

This is because the residual stress generated due to the difference in thermal expansion coefficient between polyimide and GCS is concentrated at the edges of the polyimide layer, and the adhesive strength between polyimide and GC3 or the relatively strong and fragile GCS itself cannot withstand this stress. This is a phenomenon that occurs as a result of being lost. This residual stress increases as the substrate becomes larger.

Similarly, when polyimide was simply laminated using the structure of this example shown in Figure 1 using a 160 mm x 160 mm GCS, it was found that even if the polyimide film thickness exceeded 250 μm, the polyimide peeled off from the edges and the GCS No cracks were observed. This is because the residual stress concentrated at the end of the polyimide layer 13 is dispersed by the grooves 12 and 14 formed in a lattice pattern over the entire laminated surface of the glass ceramic substrate.

Next, the swelling of the end portion of the polyimide layer 13 will be described.

When coating polyimide onto a ceramic substrate using the spin code method in the structure of this example, the polyimide layer 13
Since the end portion of the polyimide layer 13 enters the edge 12 formed at the outermost periphery of the substrate surface, a polyimide layer 13 having a flat surface is formed on the entire substrate. Conventionally, when polyimide was applied to a substrate without grooves using the spin cord method, swells occurred at the edges and the film thickness became thicker at the periphery, especially at the four corners, making it difficult to form peer holes in those areas.

In the first embodiment, the end face of the polyimide layer 13 is aligned with the outer periphery of the groove 12, but this is not necessarily necessary. FIG. 3 is a sectional view of a second embodiment in which the polyimide end face is brought inside the groove. When the grooves 22 are processed in the green sheet laminate, their positions vary due to shrinkage during firing, resulting in the structure of this embodiment. Wei 22 has a width of 2 mm and a depth of 3
00 μm.

FIG. 4 shows a third embodiment, in which the depth of the groove 32 is 1 mm. When processing the ceramic after it is fired, it is easier to process it if the grooves are made to this depth. In addition, the groove 32
The depth is deep and the stress is received on the sides, which improves the resistance to stress.

〔Effect of the invention〕

As explained above, the present invention forms a ceramic multilayer wiring board with a structure in which grooves are formed over the entire laminated surface of the ceramic multilayer wiring board, and the edges of the organic resin layers to be laminated are brought into the grooves. This has the effect of dispersing the residual stress in the organic resin layer concentrated at the edge of the substrate, thereby preventing the organic resin from peeling off from the substrate or cracking of the ceramic substrate due to stress. It also has the effect of eliminating swelling at the edges during spin coating of organic resin.

[Brief explanation of drawings]

1 and 2 are a sectional view and a plan view of a first embodiment of the present invention, and FIGS. 3 and 4 are respectively a sectional view and a plan view of a second embodiment of the present invention. Third
FIG. 11.21.31...Ceramic multilayer wiring board, 12
．． 22.32...Outermost groove, 13.23°3...
Organic resin layer (polyimide layer) 4...Internal groove.

Claims (4)

[Claims] 1. a ceramic multilayer substrate having a conductor layer inside; a groove formed on the entire laminated surface of the ceramic multilayer substrate; 1. A ceramic multilayer wiring board characterized by comprising an organic resin layer formed in such a manner as to cover the organic resin layer. 2. 2. The ceramic multilayer wiring board according to claim 1, wherein the grooves are formed in a grid pattern. 3. 3. The ceramic multilayer wiring board according to claim 1, wherein the outermost groove is formed to have a larger width and depth than the other grooves. 4. 4. The ceramic multilayer wiring board according to claim 1, wherein the organic resin layer is made of polyimide.