JPH0221669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a conductive paste prepared by kneading high-purity fine copper hydride powder and a small amount of an inorganic binder with a paste agent to form a high-purity copper film with high adhesive strength on a ceramic substrate. The present invention relates to a method for manufacturing a hybrid integrated circuit that generates a conductor pattern.

Conventionally, hybrid integrated circuit boards have been fabricated on ceramic substrates using a conductive paste made by kneading fine powder of precious metals such as gold, silver, platinum, palladium, and their alloys, and glassy frit as an adhesive. It is manufactured by applying a conductor pattern to the surface and firing it at high temperature.

However, in the conductive paste used in the production of conventional hybrid integrated circuit boards, the frit mixed therein is an electrical insulator, so even though the adhesion of the conductive film to the ceramic substrate is good, the conductive paste The drawback is that the electrical conductivity of the membrane is impaired. This decrease in electrical conductivity occurs as the frequency of the radio signal handled by the hybrid integrated circuit increases.
The impedance of this hybrid integrated circuit becomes increasingly high, which causes a significant deterioration in the circuit's function. Therefore, hybrid integrated circuit boards manufactured by the conventional method described above are particularly unsuitable for use in microwave circuits. Ta.

As a hybrid integrated circuit board for ultra-high frequency and microwave applications, the conductor film has high electrical conductivity and has a strong adhesion to the board, so that the heat generated by the functional action of the circuit on the board can be avoided. It is necessary that the material has excellent dissipation.

The present invention has been made in view of the conventional situation and with the object of making it possible to easily obtain a hybrid integrated circuit board that satisfies the above technical requirements, and by using high purity fine powder copper hydride, a small amount of an inorganic binder, etc. A conductive pattern of a hybrid integrated circuit is printed on a ceramic substrate using a conductive paste kneaded with a base agent, and after drying the printed surface appropriately in the air, the ceramic substrate is placed in an inert gas atmosphere.
By firing at a temperature in the range of 800℃ to 900℃ to form a conductor pattern of high-purity copper film that has strong adhesion to the substrate surface, the conductor film has high electrical conductivity equivalent to that of pure copper. It is an object of the present invention to provide a manufacturing method which can easily obtain a hybrid integrated circuit board having a high efficiency and excellent characteristics, particularly for use in microwaves, and which has excellent heat dissipation from the conductive film to the substrate.

Hereinafter, one embodiment of the method for manufacturing a hybrid integrated circuit board according to the present invention will be described in detail.

The ceramic substrate that makes up the hybrid integrated circuit board is a 96% pure alumina substrate with a thickness of approximately 0.8 mm. The conductive paste is made by kneading high purity copper hydride (CuHx), a small amount of 1.5% inorganic binder, and 6-4% metal oxide with about 10% paste agent. Incidentally, as the ceramic substrate, in addition to those mentioned above, a beryllia substrate or the like can be used.

In manufacturing a hybrid integrated circuit board using the above-mentioned ceramic substrate and conductive paste, first, the surface of the ceramic substrate is cleaned, and a conductive pattern of the hybrid integrated circuit is formed on the ceramic substrate using a conductive paste on a predetermined screen. and the temperature is 100
Dry for 15 min in air at °C. Next, this ceramic substrate is heated gradually in an inert gas (nitrogen gas) atmosphere and fired at a constant temperature in the range of 800°C to 900°C (for example, 850°C) for 10 minutes, and then cooled to room temperature. When returned, a dense and homogeneous conductor pattern of high-purity copper film is generated on the ceramic substrate.
The conductor film is firmly adhered to the ceramic substrate. Note that the reason for performing baking in an inert gas atmosphere is to prevent oxidation of the conductor film. Therefore, the oxygen content in the inert gas atmosphere must be kept within 10 ppm.

The reason why a conductor pattern of a high purity copper film is produced on a ceramic substrate in the manufacturing process of a hybrid integrated circuit board as described above, and that the conductor film is firmly adhered to the ceramic substrate is due to the following phenomenon.

A ceramic substrate with a conductive pattern applied with conductive paste is heated at 300℃ in an inert gas atmosphere.
When the temperature is around this temperature, the organic content of the conductive paste is released or burned and disappears. When the temperature is further increased to 400°C to 500°C, the bonded hydrogen in the copper hydride leaves the bond and is temporarily activated, which drifts within the remaining pure copper film and generates a hydrogen atmosphere within the film. Since the pure copper particles are further activated, chemical bonding between the pure copper particles is facilitated, and the adhesive strength between the high purity copper film and the ceramic substrate surface is increased. Even more temperature
At around 600°C, bound hydrogen is completely dissociated and released, and when the temperature rises to 800°C to 900°C, small amounts of inorganic binders and metal oxides increase the adhesive strength of high-purity copper films to ceramic substrates. It has a multi-promoting effect to further enhance the effect. After a certain period of time has passed in the above-mentioned high temperature state, the ceramic substrate is slowly cooled and returned to room temperature to complete the firing. After firing, the adhesive strength of the conductor film to the ceramic substrate reaches several kilograms per square millimeter, and its electrical conductivity is extremely high, equivalent to that of pure copper.

1 and 2 illustrate a hybrid integrated circuit board manufactured by the method according to the invention. In the figure, 1 is a ceramic (alumina) substrate,
2 is a conductor pattern made of high-purity copper film, 3 is an alignment mark during printing, and 4 is a terminal.

In the hybrid integrated circuit board manufactured by the method according to the present invention, the substrate is made of ceramic, and the conductive film is composed of a high-purity copper film, and the conductive film is firmly adhered to the ceramic substrate. Therefore, the electrical conductivity of the conductive film is high, and it is possible to construct a circuit that operates with high efficiency, especially for ultra-high frequency, microwave, etc. circuits. In addition, the ceramic substrate is a good conductor for heat dissipation, and since the conductor film is firmly adhered to it, heat dissipation from the conductor film to the ceramic substrate is good, and it can withstand high-temperature usage conditions. Moreover, it has high reliability even under such usage conditions.

Hybrid integrated circuits are used in general industry, computer industry,
Although they are used in many ways in the home appliance industry, their circuit elements are often used extremely harshly due to the overload of information. However, since the hybrid integrated circuit board manufactured by the method according to the present invention has the above-mentioned excellent characteristics, it can sufficiently withstand such usage conditions.

Furthermore, according to the method of the present invention, a conductive film of high-purity copper film can be extremely easily produced on a ceramic substrate, and its electrical conductivity is extremely high. There is no need to use noble metals such as platinum, palladium, etc., and a high performance hybrid integrated circuit board can be provided economically. The fact that the conductor film is a high-purity copper film has good solder wettability strength. This is also one of its features.

In summary, the present invention applies a conductive pattern of a hybrid integrated circuit onto a ceramic substrate using a conductive paste made by mixing high-purity finely divided copper hydride and a small amount of an inorganic binder with a paste agent. After drying the printed surface appropriately in the air, place the ceramic substrate in an atmosphere of unused gas.
This is a method for manufacturing hybrid integrated circuit boards in which the conductor pattern of a high-purity copper film is baked at a temperature in the range of 800°C to 900°C and has high adhesion strength to the substrate surface. This is an extremely useful novel product that has comparable high electrical conductivity, excellent heat dissipation from the conductor film to the substrate, and allows easy production of hybrid integrated circuit boards with high efficiency and good characteristics, especially for microwave applications. This is effective.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a hybrid integrated circuit board manufactured by the method according to the present invention, and FIG. 2 is a front view of the same. In the figure, 1 is a ceramic substrate, 2 is a conductor pattern of high-purity copper film, 3 is an alignment mark during printing, and 4 is a terminal.

Claims (1)

[Claims] 1. Print a conductor pattern of a hybrid integrated circuit on a ceramic substrate using a conductive paste made by mixing high-purity finely divided copper hydride and a small amount of an inorganic binder with a paste agent, and then expose the printed surface to a moderate level in the air. After drying, the ceramic substrate is fired at a temperature in the range of 800℃ to 900℃ in an inert gas atmosphere to produce a conductor pattern of high purity copper film with high adhesive strength to the substrate surface. A method for manufacturing a hybrid integrated circuit board.