JP2551064B2 - Manufacturing method of ceramic multilayer substrate - Google Patents

Description

The present invention relates to a method for manufacturing a ceramic multilayer substrate by a so-called thick film method.

[Conventional technology]

FIG. 2 is a sectional view showing an example of a conventional ceramic multilayer substrate by a thick film method.

This ceramic multi-layer substrate 1 is obtained by alternately printing conductor layers 3 and insulating layers 4 on a ceramic base material 2 such as a sintered ceramic substrate such as alumina or a ceramic green sheet, and then laminating the whole. It is manufactured by firing in the atmosphere and temperature. Then, the surface thereof is subjected to processing such as mounting of the LSI chip 6 and wire bonding, mounting of the chip capacitor 7 and soldering, and thick film printing of the resistor 8 as necessary.

[Problems to be solved by the invention]

However, according to the conventional manufacturing method as described above, since the conductor layer 3 and the insulating layer 4 are sequentially printed on the ceramic base material 2, the unevenness is gradually enlarged, and the uppermost layer is extremely uneven. Will be a big one. For this reason, in the conventional method, normally, only about 5 layers can be produced.

When a ceramic green sheet or a ceramic substrate that softens in the temperature range where the insulator layer 4 is sintered is used as the ceramic base material 2, the ceramic base material 2 and the insulator layer 4 have different shrinkage rates, and thus the ceramic multilayer substrate. There is also a problem that 1 is likely to be warped.

Therefore, an object of the present invention is to provide a method for manufacturing a ceramic multi-layer substrate that improves these points.

[Means for solving problems]

The manufacturing method of the present invention comprises a step of alternately printing and laminating conductor layers and insulator layers on a ceramic base material, and another ceramic base material is superposed on the uppermost layer of the resulting product and pressure-bonded as a whole. The method is characterized by including a step and a step of firing a product obtained thereby.

[Action]

Since the conductor layers and the insulator layers are alternately printed and laminated and sandwiched from both sides by the ceramic base material and pressure-bonded, symmetry in the thickness direction is increased, and thereby warpage of the ceramic multilayer substrate is reduced. Further, since the ceramic base material is the outermost layer, the flatness of the surface is improved.

〔Example〕

As the ceramic base material described above, a sintered ceramic substrate, a ceramic green sheet, or the like can be used.

First, an example using the former will be described with reference to FIG.
Here, an alumina substrate 12 having a thickness of 0.5 mm was used as the sintered ceramic substrate (FIG. 7A). Predetermined through holes 12h are already formed in this alumina substrate 12 by a known means.

Then, on the alumina substrate 12, a conductive paste (for example,
(Ag, Ag / Pd, Au, Cu, Ni, W, Mo, etc.) 13 was used to perform through-hole printing and surface printing for forming a conductor layer (FIG. 2B).

Then, an insulating paste (for example, an alumina paste) 14 was printed thereon to form an insulating layer (FIG. 2C). 14h is a via hole. When firing at a high temperature like alumina paste as the insulator paste, W and Mo pastes are used as the conductor paste. Also, as an insulator paste 800-100
When the one that can be fired at 0 ° C. is used, each paste such as Ag, Ag / Pd, Au, Cu, and Ni is used as the conductor paste.

Next, the same printing step of the conductor paste 13 (the same figure (D)) and the printing step of the insulating paste 14 were repeated to form 10 insulating layers (the same figure (E)). Only two layers are shown in the figure.).

Then, on the uppermost layer, put the alumina substrate 15 provided with a predetermined through hole 15h similar to the alumina substrate 12,
The whole was put into a mold and thermocompression bonded at 150 ° C. and 20 kg / cm ² (FIG. (F)).

Next, the conductor paste 13 was used to perform through-hole printing on the through-holes 15h of the alumina substrate 15 and surface printing. Further, in this example, surface printing was also performed on the alumina substrate 12 side ((G) in the same figure).

Then, finally, a ceramic multilayer substrate was obtained by firing the whole in a predetermined atmosphere in accordance with the used conductor paste 13 (FIG. 2H).

This ceramic multi-layer substrate is one in which a conductor layer and an insulator layer are laminated and sandwiched between the alumina substrates 12 and 15 from the upper and lower sides, and has a high symmetry in the thickness direction. It was equivalent to an alumina substrate.

In addition, since the outermost layers are the alumina substrates 12 and 15, there is no large unevenness as in the conventional case, and the flatness is equivalent to that of a normal alumina substrate.

Further, it has been found that it is possible to repeat the steps (C) to (G) again for the uppermost layer after the step (G) because of the high flatness.

On the other hand, as another example, when a ceramic green sheet having through holes was used instead of the alumina substrates 12 and 15 and a ceramic multilayer substrate was obtained by the same steps (B) to (H) as described above, the warpage thereof was observed. And the surface flatness was equivalent to that of a normal alumina substrate.

Of course, the ceramic base material used for sandwiching the conductor layer and the insulator layer from both sides may be a sintered ceramic substrate such as alumina and the other may be a ceramic green sheet.

〔The invention's effect〕

As described above, according to the present invention, it is possible to improve the warpage and the flatness of the surface, which are the drawbacks of the ceramic multilayer substrate manufactured by the thick film method.

As a result, it is possible to form a multilayer that exceeds the upper limit (about 5 layers) of the number of printing layers in the conventional thick film method.

In addition, since the flatness of the surface is improved, LSI chips,
Chip components such as chip capacitors can be easily mounted, and connection defects such as wire bonding and soldering between them and surface conductors can be reduced.

Further, it becomes easy to print a thick film of a resistor or the like on the surface layer, and a uniform film thickness can be obtained, so that variations in the characteristics are reduced.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method for manufacturing a ceramic multilayer substrate according to an embodiment of the present invention. FIG. 2 is a sectional view showing an example of a conventional ceramic multilayer substrate by a thick film method. 12,15 …… Alumina substrate, 13 …… Conductor paste, 14 ……
Insulator paste.

Claims (1)

(57) [Claims] 1. A step of alternately printing and laminating a conductor layer and an insulator layer on a ceramic base material, and a step of superimposing another ceramic base material on the uppermost layer of the obtained product and crimping the whole. And a step of firing the product obtained thereby, the method for producing a ceramic multilayer substrate.