JPH01321691A - Manufacture of thick-film ceramic multilayer substrate - Google Patents

Abstract

PURPOSE:To make the resistance value of a resistor approximately the same as that of the resistor on an alumina substrate even when the resistor is formed onto an insulating layer by using specific crystallized glass or crystallized glass- ceramics as the insulating layer of an uppermost section. CONSTITUTION:Paste 2 for a copper oxide conductor mainly comprising copper oxide and insulating paste 3 mainly containing glass or glass-ceramics are printed alternately onto a ceramic baked substrate 1, and the substrate 1 is thermally treated at a temperature or higher sufficient for decomposing organic components included in paste. The substrate is thermally treated at a temperature from a temperature, where copper oxide is reduced to metallic copper, to the sintering temperature of the insulating layer 3 in a reducing atmosphere. The insulating layer is sintered in an atmosphere brought to a non-oxidizing state to copper, and insulating paste composed of crystallized glass or crystallized glass-ceramics having a crystallization temperature within a temperature range of 800-900 deg.C and high crystallinity is employed for forming an insulating layer 4 as an uppermost section. Accordingly, even when a thick film resistor 5 is shaped onto the insulating layer 4, the resistance value of the resistor 5 is approximately equal to a resistance value on the alumina substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thick-film ceramic multilayer substrate that can be used as a high-density mounting board for circuits on which ICs, LSIs, chip components, etc. are mounted and interconnected. This relates to a manufacturing method.

Conventional technology In recent years, thick film multilayer boards using copper as the conductor material are being considered for practical use in many fields because thick film paste is readily available and the manufacturing method is simple, making it relatively easy to manufacture. There is. A characteristic required of the insulating layer of a multilayer board is good insulation between wiring layers. For this reason, in general, amorphous glass or crystallized glass having a crystallization temperature higher than the firing temperature is used to densify the insulating layer.

On the other hand, from the point of view of surface mounting, it is more advantageous to form all thick film resistors where possible than to construct the entire surface of a multilayer board with chip components.

Problem to be Solved by the Invention However, when a thick film resistor is formed on an amorphous glass or glass-ceramic insulating layer, the resistance value is significantly lower than that on an alumina substrate. It is difficult to form thick film resistors.

The present invention was made to solve the above problems, and provides a thick film ceramic multilayer substrate on which a thick film resistor can be formed on an insulating layer.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a paste for a copper oxide conductor containing copper oxide as a main component and glass or glass-ceramic as a main component on a ceramic sintered substrate. a step of alternately printing an insulating paste to form a multilayer wiring; a step of heating the substrate in air or an oxidizing atmosphere at a temperature sufficient to decompose the organic components contained in the paste; A step of performing heat treatment in a post-reducing atmosphere at a temperature below the temperature at which the insulating layer is sintered and above a temperature at which the copper oxide is reduced to metallic copper, and further in an atmosphere that is non-oxidizing to copper. A step of sintering the insulating layer, and in order to form the uppermost insulating layer exposed on the surface, a crystallization process that maintains the entire crystallization temperature in the temperature range of 800 to 900°C and has a high degree of crystallinity. An insulating paste made of glass or crystallized glass-ceramic is used.

Function As described above, the present invention has a crystallization temperature in the temperature range of 800 to 900°C in the uppermost insulating layer exposed to the surface,
In addition, since crystallized glass or crystallized glass-ceramic with a high degree of crystallinity is used, even if a thick film resistor is formed on an insulating layer, the resistance value is almost the same as that on an alumina substrate.

EXAMPLES Hereinafter, a method for manufacturing a thick film ceramic multilayer substrate according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a manufacturing process diagram of a thick-film ceramic multilayer substrate according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an example of the thick-film ceramic multilayer substrate.

First, a wiring layer 2 is screen printed using a copper oxide paste on a fired alumina substrate 1 and dried. The copper oxide (CuO) used at this time had an average particle size of 3 μm. The vehicle for making the paste was a mixture of terpineol, benzyl alcohol, and butylcarpitol dissolved in polyvinyl butyral as an organic binder, and the mixture was kneaded with the copper oxide powder to form a paste. .

Next, crystallized glass whose crystallization temperature is 900°C or higher (
The first product was prepared by kneading an inorganic composition (average particle size 2 μm) containing lead borosilicate (lead borosilicate) powder and alumina powder in a weight ratio of 50:6 and a vehicle in which polyvinyl butyral was dissolved in a butyrate solvent. Screen printing was applied to desired areas on the copper oxide wiring and the fired alumina substrate 1 with an insulating paste, and the resultant paste was dried to form an unfired first insulating layer 3. Subsequently, an inorganic composition was prepared in which the total weight ratio of crystallized glass (lead borosilicate) powder and alumina powder having a crystallization temperature in the temperature range of aOO to 900° C. was blended at 60:6.
A second particle prepared by kneading a vehicle with an average particle size of 2 μm) and a vehicle prepared by dissolving polyvinyl butyral in a butyric acid ester solvent.
The insulating paste was layered on the first insulating layer 3 and screen printed, and dried to form an unfired second insulating layer 4. Although terpineol, benzyl alcohol, butylcarpitol, butyric acid ester, and polyvinyl butyral were used to prepare the copper oxide paste and insulating paste, ethyl cellulose or acrylic resin may also be used as the organic binder, and sorbitan alkyl ester may also be used as the organic binder. It is also an effective means to use a surfactant such as polyoxyethylene alkyether. Furthermore, a top wiring layer was formed using the copper oxide paste. The printed substrate was heated in air to 300 to 700°C to completely remove the organic components in the paste and remove the binder. Subsequently, after reducing the oxidized steel to metallic copper at 300 to 500'C in a nitrogen gas atmosphere containing 5 to 40% hydrogen gas,
The metallic copper and the unfired first and second insulating layers 3.4 were fired simultaneously at 900'C in a nitrogen gas atmosphere.

Note that the second insulating layer 4 on the top of the substrate obtained in the example
When the resistor 6 was formed on the alumina fired substrate 1, the resistance value was almost the same as that when the resistor was formed on the alumina fired substrate 1. The result is that the crystallization temperature of the top insulating layer is 900℃.
The results are shown in the table below together with the results when using the above crystallized glass-alumina.

*Based on resistance value on alumina substrate.

Effect of the invention According to the present invention, the following effects can be obtained.

(1) The top insulating layer has a crystallization temperature range of SOO~9.
Since crystallized glass or crystallized glass-ceramic, which is heated to 00° C. and has a high degree of crystallinity, is used, even if a resistor is formed on an insulating layer, the value is almost the same as that on an alumina substrate.

(2) Use crystallized glass or crystallized glass-ceramic with a crystallization temperature range of 800 to 900°C and a high degree of crystallinity for the uppermost insulating layer (second insulating layer);
The insulating layer is made of amorphous glass or has a crystallization temperature of 9
Since glass having a temperature of 00° C. or higher is used, the insulation between wiring layers is good.

[Brief explanation of the drawing]

FIG. 1 is a manufacturing process diagram of a thick film ceramic multilayer substrate according to an embodiment of the present invention, and FIG. 2 is a sectional view of the thick film ceramic multilayer substrate. 1... Alumina firing, substrate, 2... Wiring layer, 3... First insulating layer, 4... Second insulating layer. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 2

Claims (1)

[Claims] A step of alternately printing a copper oxide conductor paste containing copper oxide as a main component and an insulating paste containing glass or glass-ceramic as a main component on a fired ceramic substrate to form a multilayer wiring; A step of heat treatment in an oxidizing atmosphere at a temperature higher than sufficient to decompose the organic components contained in the paste, and then a step of heat treatment in a reducing atmosphere at a temperature lower than the temperature at which the insulating layer is sintered and the copper oxide becomes a metal. A step of heat-treating the insulating layer at a temperature higher than that at which it is reduced to copper, and a step of sintering the insulating layer in an atmosphere that is non-oxidizing to copper. A thick film ceramic characterized in that an insulating paste made of crystallized glass or crystallized glass-ceramic having a crystallization temperature in the temperature range of 800 to 900°C and having a high degree of crystallinity is used to form the layer. A method for manufacturing a multilayer board.