JPH07263469A - Semiconductor device - Google Patents

Abstract

PURPOSE:To suppress occurrence of a void in a semiconductor device in which a semiconductor chip is connected to a member for fixing the chip by a brazing material by using the material molded in a spherical state. CONSTITUTION:A semiconductor device has a semiconductor chip 3 connected to a member 1 for fixing the chip 3 by a first brazing material, and uses a brazing material 5 molded in a spherical state as a brazing material. For example, a recess 6 is provided at a member position of the chip 3 substantially corresponding to a center of the member 1 made, for example, of metal to become an electrode, heat buffer metal, a thermal conductive ceramics for insulating the chip from a metal board, etc. The material 5 is placed in the recess 6 of the member 1, and the chip 3 is placed on the material 5. Thus, the material 5 is heated in an inert or reducing atmosphere higher by several - several tens of degrees than a melting point of the material 5 in a positioned state, melted and brazed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a void generated in a brazing material layer when a semiconductor chip is brazed to a member such as a metal or a ceramic having good thermal conductivity, or between a metal substrate and the ceramic. The present invention relates to a semiconductor device in which the temperature is reduced and local concentration of heat is suppressed.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device in which a semiconductor chip of this type and a member 1 made of a metal or a ceramic having good thermal conductivity is used as an electrode is made of a member as shown in FIG. It was That is, a soldering material 2 which is formed into a pellet shape and has substantially the same size as a semiconductor chip without containing a paste is mounted on a member 1 serving as a base, and a semiconductor chip 3 is mounted on the soldering material 2 and the soldering state is maintained. The brazing material is welded in an inert atmosphere or a reducing atmosphere having a temperature of several degrees to several tens of degrees higher than the melting point of the material, and is cooled and solidified.

[0003]

However, when a brazing filler metal formed into a pellet shape is used, when the brazing filler metal is melted in the reflow process, the difference in the compatibility between the semiconductor chip or member surface and the brazing filler metal causes As shown in Fig. 5, there were many cases where welding was performed with the void 4 included. This void not only loses the mechanical strength between the semiconductor chip and the member, but the heat of the semiconductor chip cannot be dissipated by the void when the semiconductor device is used, and the heat is locally concentrated and partial heating occurs, which is not allowed. There is a problem that the semiconductor device is damaged unless the current is reduced.

In view of this problem, the present invention intends to improve the shape of the brazing material and suppress the generation of voids.

[0005]

That is, according to the present invention, in a semiconductor device in which a semiconductor chip and a member for fixing the semiconductor chip are connected by a first brazing material, the brazing material in which the brazing material is formed into a spherical shape. Is used.

Also, in the semiconductor device in which the ceramic having the metal layers on both surfaces and the semiconductor chip being brazed on one surface is connected to the metal substrate by the second brazing material, the second brazing material is used. The material is a brazing material formed into a spherical shape.

Further, the second brazing material is a brazing material in which the paste is provided only on the surface.

Also, a positioning recess for the first brazing material is provided at a member position corresponding to substantially the center of the semiconductor chip, and the second solder is provided on at least one of the metal substrate and the ceramic. The brazing material is provided with a positioning recess.

[0009]

[Function] Since the spherically shaped brazing filler metal is used between the semiconductor chip and the member, when the brazing filler metal is melted, the spherical brazing filler metal and the semiconductor chip and the spherical brazing filler metal and the member are connected to the surrounding area. Since the brazing material spreads, the generation of voids can be suppressed.

Further, since the spherically shaped brazing material is used between the brazed ceramic and the metal substrate, the spherical brazing material and the ceramic and the spherical brazing material and the metallic substrate are melted when the brazing material is melted. Since it spreads from the contacting part to the periphery, voids can be suppressed.

Further, since the paste is provided only on the surface of the spherical brazing material, the ceramic and the metal substrate can be easily adhered, and the gas due to the paste is sent to the outside as the spherical brazing material melts, so that the generation of voids is suppressed. To be done.

By providing a recess in the center of the member, the metal substrate, and the ceramic, the spherical brazing material can be positioned.
Since the member in contact with the brazing material spreads from the center to the periphery, brazing can be performed uniformly and the generation of voids is suppressed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. In FIG. 1, 3 is a semiconductor chip, 1 is a metal serving as an electrode, metal for heat buffering between a semiconductor chip and a metal substrate, such as molybdenum / tungsten, etc., having metal layers on both sides to insulate the semiconductor chip and the metal substrate. The member 6 is a member having good thermal conductivity such as ceramics, and the recess 6 is provided at a member position corresponding to substantially the center of the semiconductor chip 3. Reference numeral 5 is a spherical brazing material such as a soccer ball or a rugby ball. Then, the spherical brazing filler metal 5 is mounted in the recess 6 on the base member 1, and the semiconductor chip 3 is mounted on the upper portion of the brazing filler metal.

In this way, when the brazing material is heated in an inert atmosphere or a reducing atmosphere, which is several degrees to several tens of degrees higher than the melting point of the brazing material in the state of being positioned as shown in FIG. 2A,
As shown in FIG. 3B, the brazing material melts from the outside. When the entire brazing filler metal 5 is melted, the portion contacting the member 1 and the semiconductor chip 3 spreads from the center of the lower portion of the semiconductor chip 3 to the periphery as shown in FIGS. Stabilizes at the edges by surface tension. Then, as shown in FIG. 3E, the molten brazing material is spread over the entire surface of the semiconductor chip and is cooled and fixed.

As a result, when the brazing material is melted, the brazing material spreads from the portion where the spherical brazing material 5 contacts the semiconductor chip 3 and the spherical brazing material 5 and the member 1 to the surroundings, so that voids are suppressed. The amount of the spherical brazing filler metal 3 has such a thickness that the semiconductor chip 3 and the member 1 can have a sufficient mechanical connection, and
An amount is chosen that has a low thickness and a low thermal resistance of the braze material layer.

FIG. 3 shows another embodiment, which is different from that shown in FIG. 1 in that a spherical brazing filler metal 5 is provided with corners 5a like Konpeito. The spherical brazing material having the corners facilitates the positioning of the semiconductor chip 3 and the member 1, and can support the semiconductor chip 3 by the corners 5a.
When the semiconductor chip and the member are positioned and heated, the spherical corners are also melted. At this time, the corner melted by the surface tension is absorbed by the spherical brazing filler metal body, and no void is generated by the corner. Further, by providing the corner, the concave portion for positioning can be removed from the member.

In the above embodiment, the spherical brazing filler metal does not contain the paste, but the paste can be provided only on the surface of the spherical brazing filler metal. This facilitates the brazing of the members to each other, for example, the heat buffer material and the ceramic, and the ceramic and the metal substrate. Further, since the gas generated by the paste is sent to the outside as the spherical brazing material melts, the generation of voids is suppressed. Also,
In the above embodiment, the brazing between the semiconductor chip and a member for fixing the semiconductor chip such as metal or ceramic having metal layers on both sides has been described, but between the ceramic to which the semiconductor chip is fixed and the metal substrate supporting the same. It can also be applied to brazing. In addition, the above embodiment is the semiconductor chip 1.
On the other hand, although the member 1 is dealt with, a plurality of semiconductor chips can be brazed to one member.

[0018]

According to the present invention, by using a spherically shaped brazing material as the brazing material, the brazing material spreads from the portion where the brazing material and the semiconductor chip and the brazing material and the member are in contact with each other to the occurrence of voids. Can be suppressed. Also,
Since the paste is provided only on the surface of the spherical brazing material,
The bonding between the ceramic and the metal substrate becomes easy, and the gas due to the paste is sent out as the spherical brazing material melts, and the generation of voids is suppressed. Further, by engaging the brazing material with the concave portion provided in the member, the semiconductor chip and the member can be easily positioned.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an embodiment of a semiconductor device of the present invention.

2 (a) to (e) are explanatory views of a semiconductor device manufacturing process of the present invention.

FIG. 3 is a schematic perspective view of another embodiment of the semiconductor device of the present invention.

FIG. 4 is a schematic perspective view of a conventional semiconductor device.

FIG. 5 is a schematic view after brazing of a conventional semiconductor device.

[Explanation of symbols]

 1 Member 3 Semiconductor Chip 5 Spherical Brazing Material 6 Recess

Claims (6)

[Claims] 1. A semiconductor device for connecting a semiconductor chip and a member for fixing the semiconductor chip by a first brazing material, wherein the brazing material is a spherical brazing material. apparatus. 2. The semiconductor device according to claim 1, wherein the member is a metal or a ceramic having metal layers on both sides. 3. The semiconductor device according to claim 1, wherein a positioning recess for the brazing material is provided at a member position corresponding to substantially the center of the semiconductor chip. 4. A semiconductor device in which a ceramic having a metal layer on both sides and a semiconductor chip being brazed on one side is connected to a metal substrate by a second brazing material, wherein the second brazing material is used. A semiconductor device characterized in that a brazing material formed into a spherical shape is used. 5. The semiconductor device according to claim 4, wherein the second brazing material is a brazing material in which a paste is provided only on the surface. 6. The semiconductor device according to claim 1, wherein at least one of the metal substrate and the ceramic is provided with a recess for positioning the second brazing material.