JPH04125994A - Multilayered ceramic substrate and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the joining strength between pins and a multilayered ceramic substrate by inserting each pin having a projecting section at part into a laminated body of green sheets and simultaneously sintering the laminated body of green sheets, pins and gold via conductors respectively formed below the pins in advance. CONSTITUTION:Each pin 12 having a projecting section 14 is erected at a prescribed location of a laminated body of green sheets 10. While each the pin 12 is inserted into the laminated body at the time of pressing the laminated body, a gold via conductor 16 is arranged below each pin 12 in advance. After inserting the pins 12, this multilayered ceramic substrate is formed by simultaneously sintering the laminated body of green sheets 10, pins 12, and conductors 16. Therefore, a decline in the joining strength between the pins and this ceramic substrate caused by clearances produced between the pins and substrate can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a manufacturing method for erecting terminal pins on a ceramic multilayer board, and to a ceramic multilayer board manufactured by this method.

[Prior Art] In response to the miniaturization and higher density of electronic circuits in recent years, ceramic substrates are becoming more multilayered. Attention has been paid.

As a conventional substrate material, an alumina multilayer substrate, which has excellent properties from the viewpoint of heat dissipation, thermal expansion coefficient, dimensional stability, etc., has occupied an important position. However, since the firing conditions for alumina generally require a high temperature of 1500°C or higher, the conductor material is MO or W, which is a heat-resistant metal.
The scope of use was limited. Further, since it is necessary to withstand high-temperature firing, certain restrictions have been imposed on resistor materials and the like.

In order to overcome these problems of alumina multilayer substrates and expand the scope of use of electronic components such as conductor materials and resistor materials, we have created substrates of sufficient quality even at low firing temperatures, generally around 900°C. As a result, in recent years, materials such as glass powder, which can be fired at temperatures of 700°C or less to 1000°C, have been developed, and by using materials that meet regulations such as glass powder, it has become possible to combine substrates and conductive pastes, for example, into multilayer wiring boards. Low-temperature firing substrates that can be fired at the same time have been put into practical use. In general, low-temperature fired substrates have advantages such as being able to be screen printed with conductors, having high conductivity, and having excellent high frequency characteristics.

By using such low-temperature fired substrates, the scope of use of conductor materials and resistor materials can be expanded, and higher performance substrates can be provided. Mixed accumulation port F where density is required
! Low-temperature fired substrates have come to be widely used in f1 (hybrid IC) and the like.

Ceramic substrates generally have terminal pins standing upright at predetermined positions for electrical connection with the outside world, but as mentioned above, the ceramic substrates that have been commonly used are made of aluminum oxide. Since the alumina substrate is fired at a high temperature of 1500 to 1600'C, at the green sheet stage before firing,
It was not possible to pre-install the pins in place.

In the conventional manufacturing method, as shown in FIG. 2, Ni plating 34 is applied to a conductor pattern 32 of a high melting point material such as W or No formed on the surface of an alumina substrate 30 during sintering, and A! 11/Cu alloy, etc., terminal pins 38 coated with agent 36 are arranged and erected by brazing. For this reason, the mechanical strength of the terminal pin 38, such as bending and tension, was not sufficient. Furthermore, when arranging the pins, the substrate shrinks due to firing and the predetermined #C connection position changes, so the process is complicated, such as having to position each terminal pin.

In order to solve these problems, the present applicant previously proposed in Japanese Patent Application No. 2-194056 a rod-shaped green sheet at a predetermined position of a multi-layer or single-layer green sheet made of a ceramic for low-temperature firing made of glass-ceramic material. Set up the pin of
We proposed a method for manufacturing low-temperature firing circuit boards, which is characterized by subsequently firing at a low temperature. However, when placing pins upright on a ceramic multilayer board, the metal pin material and the ceramic have different coefficients of thermal expansion, which tends to create gaps between the pin and the ceramic, resulting in a decrease in bonding strength. I understand.

[Problems to be Solved by the Invention] The present invention improves a ceramic multilayer board manufactured by arranging terminal pins in advance on a green sheet and firing them simultaneously, and improves the coefficient of thermal expansion between the metal of the pin material and the ceramic. It is an object of the present invention to provide a ceramic multilayer substrate and a method for manufacturing the same that can avoid a decrease in bonding strength due to the generation of gaps between pins and ceramics due to differences in bonding strength, and can improve bonding strength.

[Means for Solving the Problems] According to the present invention, rod-shaped pins are erected at predetermined positions of a green sheet made of a ceramic for low temperature firing made of a glass ceramic material, and then firing is performed at a low temperature. Provided is a method of manufacturing a ceramic multilayer substrate, which is characterized in that a pin having a portion of a convex portion is driven in during pressing, a gold via conductor is previously placed under the pin, and co-firing is performed.

A gold via conductor is a via conductor that contains gold, and meets the following conditions: ■ It does not change in quality in the atmosphere at 1700 to 1000 degrees Celsius, and its hardness does not decrease. ■ It firmly joins to the metal body that is the conductor of the board. It is preferable to use one that satisfies the requirements.

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

Examples of low-temperature firing ceramics made of glass-ceramic materials that can be used in the present invention include lead borosilicate glass-alumina. I do.

The material of the pins erected on the green sheet may be any commonly used material, such as Au-Pt-AQ gold alloy.

The convex portion of the pin preferably has a diameter of about 200 to 300% of the diameter of the pin.

A gold via conductor having strong bonding properties with the pin is formed under the pin having such a convex portion, and the diameter of this gold via conductor is preferably approximately the same as the diameter of the convex portion of the pin. Further, the vertical thickness of the gold via conductor is preferably 0.2 to 0.6 nr.
It should be around g.

[Operations] As mentioned above, the applicant used a glass-ceramic material that can be fired at a low temperature of usually 1000°C or less as a ceramic material, so that the pins would not change in quality due to firing and the terminal pins could be formed at the green sheet stage. We proposed a method for manufacturing low-temperature firing circuit boards that can be fired while standing upright.

However, when placing pins upright on a ceramic multilayer board, the metal pin material and the ceramic have different coefficients of thermal expansion, which tends to create gaps between the pin and the ceramic, resulting in a decrease in bonding strength. I understand.

The present invention aims to solve these problems, and when manufacturing a ceramic multilayer board, a pin having a partially convex portion is driven into the press, and a gold via conductor is placed under the pin in advance. , are fired simultaneously.

That is, the present invention utilizes the material properties of the gold via conductor, which has strong bondability with pins, and also attempts to improve the bonding strength from a structural perspective by shaping the via itself into a predetermined shape.

[Example] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples.

FIG. 1 is a diagram schematically showing how pins are erected on the ceramic multilayer substrate of the present invention. As shown in FIG. 1, a rod-shaped pin 12 was 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 had a convex portion 14 in a part. .

This pin was driven in during pressing, and a gold via conductor 16 was previously placed under the pin. A ceramic multilayer substrate was produced by pressing and then simultaneously firing.

Lead borosilicate glass-alumina is used as the glass ceramic material, and the pin material is Au-Pt-AQ gold alloy or N1-Cr-A! Gold alloy was used, and firing was performed at 900° C. in a conventional manner.

The pin has a diameter of 0.41lrl and a length of 3. Onm's one was used. The size of the convex portion of the pin was 0.8 inches in diameter and 0.2 Ilm in length. The size of the gold via conductor portion was 0.8 inch in diameter and 0.2 nn+ in length.

The obtained ceramic multilayer board avoids a decrease in bonding strength due to the generation of gaps between the pins and the ceramic, and
The bonding strength was improved.

[Effects of the Invention] As explained above, according to the present invention, a ceramic multilayer board manufactured by erecting terminal pins in advance on a green sheet and co-firing is improved, and the gap between the metal of the pin material and the ceramic is improved. Provided are a ceramic multilayer substrate and a method for manufacturing the same, which can avoid a decrease in bonding strength due to the generation of gaps between pins and ceramics due to differences in thermal expansion coefficients, and can improve bonding strength.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing how pins are erected on a ceramic multilayer substrate according to the present invention, and FIG. 2 is a diagram illustrating how terminal pins are erected by a conventional method. 10... Green sheet 12... Terminal pin 14.
...Convex portion 16...Gold via conductor 30...
Alumina substrate 32...Conductor pattern 34...N Plating 36...Brazing agent 38...Terminal pin

Claims (3)

[Claims] (1) A rod-shaped pin is set upright at a predetermined position on a green sheet made of a glass-ceramic material for low-temperature firing, and then fired at a low temperature. A method for manufacturing a ceramic multilayer board, characterized by placing gold via conductors in advance under the pins and firing them at the same time. (2) Use a gold via conductor that satisfies the following conditions: 1. It does not change in quality or decrease in hardness in the atmosphere at 700 to 1000°C, and 2. It firmly joins to the metal body that is the conductor of the board. 2. The method according to claim 1. (3) A ceramic multilayer substrate manufactured by the method according to claim 1 or 2.