JP3139759B2 - Ceramic multilayer substrate and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a manufacturing method for erecting terminal pins on a ceramic multilayer substrate, and a ceramic multilayer substrate manufactured by this method.

[Prior Art] In recent years, ceramic substrates have been multi-layered in response to miniaturization and densification of electronic circuits. Attention has been paid.

As a conventional substrate material, an alumina multilayer substrate having excellent characteristics from the viewpoint of heat dissipation, thermal expansion coefficient, dimensional stability, and the like occupies an important position. However, since the firing conditions of alumina generally require a high temperature of 1500 ° C. or more, the range of use has been limited to heat-resistant metals such as Mo and W as conductive materials. In addition, since it is necessary to withstand high-temperature firing, certain restrictions have been imposed on the resistor material and the like.

In order to overcome such problems of the alumina multilayer substrate and expand the range of use of electronic components such as conductor materials and resistor materials, a substrate of sufficient quality was manufactured even at a low firing temperature of about 900 ° C. In recent years, by using several materials such as glass powder that can be fired even at 700 ° C. or less to about 1000 ° C., for example, a substrate and a conductive paste can be used as a multilayer wiring board. Low-temperature fired substrates that can be fired simultaneously have been put to practical use. In general, low-temperature fired substrates have advantages such as the ability to screen print conductors, high conductivity, and excellent high frequency characteristics.

By using such a low-temperature fired substrate, the range of use of the conductive material and the resistor material can be expanded, and a higher-performance substrate can be provided. Low-temperature fired substrates have been widely used in hybrid integrated circuits (hybrid ICs) and the like that require higher density.

In general, terminal pins for obtaining electrical connection with the outside are provided upright at predetermined positions on a ceramic substrate, but those that have been frequently used as ceramic substrates in the past are made of aluminum oxide as described above. Since the alumina substrate is fired at a high temperature of 1500 to 1600 ° C., it was not possible to attach pins to predetermined positions in advance at the stage of the green sheet before firing.

In the conventional manufacturing method, as shown in FIG. 2, a Ni plating 34 is applied to a conductor pattern 32 of a high melting point material such as W or Mo formed on the surface of an alumina substrate 30 during sintering, and the Ag / C
The terminal pins 38 coated with a brazing agent 36 such as a u-alloy are arranged and are erected by brazing. For this reason, terminal pins
The mechanical strength such as bending and pulling of 38 was not enough. In addition, when arranging the pins, since the substrate shrinks due to baking and the predetermined connection position changes, the process is complicated, such as the need to position each terminal pin.

In order to solve such a problem, the present applicant has previously filed Japanese Patent Application No. 2-194056 as a rod-shaped sheet at a predetermined position of a multi-layer or single-layer green sheet made of glass ceramic material for low-temperature firing. A method for manufacturing a low-temperature fired circuit board, characterized in that the pins are erected and then fired at a low temperature. However, when pins are erected on a ceramic multilayer substrate, the thermal expansion coefficient between the metal of the pin material and the ceramic differs, so that a gap is generated between the pins and the ceramic, and the bonding strength tends to decrease. I understand.

[Problems to be Solved by the Invention] The present invention is to improve a ceramic multilayer substrate manufactured by erecting and simultaneously firing terminal pins on a green sheet, and to obtain a coefficient of thermal expansion between metal and ceramic of the pin material. It is an object of the present invention to provide a ceramic multilayer substrate capable of improving the bonding strength by avoiding a decrease in the bonding strength caused by the generation of a gap between the pin and the ceramic due to the difference between the two, and a method of manufacturing the same.

[Means for Solving the Problems] According to the present invention, a rod-shaped Au-Pt-Ag alloy or a Ni-Cr-Al alloy is selected at a predetermined position of a green sheet made of a low-temperature firing ceramic made of a glass ceramic material. It consists of erecting a pin made of the material that has been fired and then firing at low temperature, integrating the gold via conductor and the inner conductor,
The end of the pin having a protrusion on its outer surface is brought into contact with
A method for producing a ceramic multilayer substrate characterized by simultaneous firing at 000 ° C. is provided.

The gold via conductor is a via conductor containing gold and satisfies the following conditions: it does not deteriorate in the air at 700 to 1000 ° C and does not decrease in hardness; it is firmly connected to the metal body that is the conductor of the substrate. It is preferable to use one that does.

Further, according to the present invention, there is provided a ceramic multilayer substrate manufactured by the above-described method.

As a low-temperature firing ceramic comprising a glass ceramic material that can be used in the present invention, for example, lead borosilicate glass
Alumina and the like can be exemplified, and sintering is preferably performed at a temperature of 700 to 1000 ° C. using such a ceramic.

The material of the pins erected on the green sheet may be a commonly used material, for example, an Au-Pt-Ag alloy or the like can be used. This pin has a diameter of 10
It has a projection having a diameter about 0% larger.

This pin is brought into contact with the outer surface of the integrated gold via conductor and the inner conductor. In this case, the integration of the gold via conductor and the internal conductor may be made of one constituent unit or two constituent units. Generally, the diameter of the gold via conductor is preferably about the same as the diameter of the pin. The thickness of the gold via conductor in the vertical direction is preferably
0.4 to 0.6 mm.

[Operation] As described above, the present applicant previously used a glass ceramic material that can be fired at a low temperature of usually 1000 ° C. or less as a ceramic material, and there was no deterioration of the pins due to firing, and the terminal pins were formed at the green sheet stage. A method for manufacturing a low-temperature fired circuit board capable of standing and firing is proposed. However, when pins are erected on the ceramic multilayer substrate, the thermal expansion coefficient between the metal of the pin material and the ceramic is different,
It has been found that a gap is formed between the pin and the ceramic, and the bonding strength tends to decrease.

The present invention is intended to solve such a problem,
In manufacturing a ceramic multilayer substrate, a gold via conductor and an internal conductor are integrated, and a pin end having a convex portion is brought into contact with an outer surface thereof, and simultaneously fired.

That is, the present invention intends to further utilize the material properties of the gold via conductor having a strong bonding property with the pin and further improve the bonding strength by integrating the gold via conductor with the internal conductor.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited only to the following examples.

FIG. 1 is a view schematically showing how a pin is erected on a ceramic multilayer substrate according to the present invention. As shown in FIG. 1, a bar-shaped pin 12 is erected at a predetermined position on a green sheet 10 made of a ceramic for low-temperature firing made of a glass ceramic material, and this pin has a projection 14. This pin was brought into contact with the outer surfaces of the integrated gold via conductor 16 and the inner conductor 18. When integrating the gold via conductor and the inner conductor,
FIG. 1a shows that both consist of one structural unit,
FIG. 1b shows one consisting of two constituent units.

Lead borosilicate glass-alumina is used as the glass ceramic material, and the pin material is Au-Pt-Ag alloy or Ni-
A Cr-Al alloy was used, and firing was performed at 900 ° C by a conventional method.

The pin used had a diameter of 0.4 mm and a length of 4.0 mm. The projection of the pin had a diameter of 0.8 mm and a length of 0.2 mm. The size of the gold via conductor was 1.0 mm in diameter and 0.4 mm in length.

In the obtained ceramic multilayer substrate, a decrease in bonding strength due to the generation of a gap between the pin and the ceramic was avoided, and the bonding strength was improved.

[Effects of the Invention] As described above, according to the present invention, a ceramic multilayer substrate manufactured by previously erecting terminal pins on a green sheet and firing them simultaneously is improved, so that the pin material and the ceramic can be interposed. The present invention provides a ceramic multilayer substrate capable of avoiding a decrease in bonding strength due to the generation of a gap between a pin and a ceramic due to a difference in thermal expansion coefficient between the pins and improving the bonding strength, and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a view schematically showing how pins are erected on a ceramic multilayer substrate of the present invention, and FIG. 2 is a view showing how terminal pins are erected by a conventional method. 10 ... Green sheet, 12 ... Terminal pin 14 ... Protrusion, 16 ... Gold via conductor 18 ... Inner conductor 30 ... Alumina substrate, 32 ... Conductor pattern 34 ... Ni plating, 36 ... Brazing Agent 38 ... Terminal pin

Claims (3)

(57) [Claims] 1. A pin made of a material selected from a bar-shaped Au-Pt-Ag alloy and a Ni-Cr-Al alloy is erected at a predetermined position on a green sheet made of a low-temperature firing ceramic made of a glass ceramic material. After that, baking is performed at a low temperature, the gold via conductor and the internal conductor are integrated, and the pin end having a protrusion on the outer surface is brought into contact, 700-1000
A method for producing a ceramic multi-layer substrate, characterized in that co-firing is performed at ℃. 2. The gold via conductor satisfies the following conditions: 1. 700 to 1000 ° C., does not deteriorate in the air and does not decrease in hardness, 2. satisfactorily bonds to a metal body which is a conductor of a substrate. A method according to claim 1, wherein said method is used. 3. A ceramic multilayer substrate manufactured by the method according to claim 1.