JPH06268099A - Ceramic package for semiconductor device - Google Patents

Abstract

PURPOSE:To prevent warpage of a heat sink by using the sink in which sintered integral metals having different thermal expansion coefficients at front and rear surfaces in such a manner that the coefficient of a connecting part to a package body is similar to that of a package body and the coefficient of a semiconductor element placing part is similar to that of a semiconductor element. CONSTITUTION:A heat sink 22 is formed integrally with sintered metals having different thermal expansion coefficients at a connecting part of a semiconductor element placing part to a package body. The coefficient of a part to be brazed to the body 20 is formed of a sintered metal A having a thermal expansion coefficient near that of ceramics of the body 20. The coefficient of a part to be placed with a semiconductor element 23 is formed of sintered metal B having a thermal expansion coefficient near that of Si of the element 23. Thus, no warpage is generated at the sink, and the package in which adverse influence is not affected to the element to be placed can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic package for semiconductor devices.

[0002]

2. Description of the Related Art A package in which a semiconductor element such as a CPU that generates a large amount of heat is mounted is required to have excellent heat dissipation. Therefore, there is known a ceramic package in which the semiconductor element 10 is mounted on a metal heat sink 11 as shown in FIG. The heat sink 11 is made of a Cu-W alloy, a Cu-Mo alloy, a Cu-Ni-W alloy or the like, which has excellent heat dissipation. On the other hand, the thermal expansion coefficient of these alloys substantially matches the thermal expansion coefficient of the ceramic of the package body 12, but since the difference in the thermal expansion coefficient between Si of the semiconductor element 10 is large, the Mo plate having a thermal expansion coefficient close to that of Si is used. 13 is brazed on the heat sink 11
A semiconductor element is mounted on the o plate 13.

[0003]

As described above, the thermal expansion coefficients of the heat sink 11 and the package body 12 are substantially matched with each other, and thermal brazing hardly occurs when brazing them with a brazing material. Further, since the thermal expansion coefficients of the Mo plate 13 and the semiconductor element are almost matched, thermal strain does not occur between them. However, the heat sink 11
The difference in the coefficient of thermal expansion between the Mo plate 13 and the Mo plate 13 is large, and the heat sink 11 and the Mo plate 13 are warped, and the semiconductor element 10
There is a problem that adversely affects.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a ceramic package for a semiconductor device capable of preventing the heat sink from warping.

[0005]

The present invention has the following constitution in order to achieve the above object. That is, in a ceramic package for a semiconductor device, in which a metal heat sink is joined to a ceramic package body, and a semiconductor element is mounted on the heat sink, the heat sink is formed by being integrally sintered, The thermal expansion coefficient is different between the joint part and the mounting part of the semiconductor element,
The thermal expansion coefficient of the joint portion with the package body has a thermal expansion coefficient similar to that of the package body, and the thermal expansion coefficient of the semiconductor element mounting portion has a thermal expansion coefficient similar to that of the mounted semiconductor element. There is. The heat sink has a Cu-W, Cu-Mo, or Cu-Ni-W-based sintered metal bonded to the package body and has a Cu content of 10 to 15%.
The content of Cu in the semiconductor element mounting portion is 0 to 10% W-Cu system or the content of Cu is 0 to 10% Mo-C.
It is preferable to use a u-based sintered metal.

[0006]

According to the ceramic package for a semiconductor device of the present invention, it is an integral sintered metal having different thermal expansion coefficients on the front and back sides, and the thermal expansion coefficient of the joint portion to the package body is similar to that of the package body. Since the heat sink having the coefficient of expansion and the coefficient of thermal expansion of the semiconductor element mounting portion is the same as that of the semiconductor element is used, the heat sink does not warp.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of a ceramic package 10 for a semiconductor device. Reference numeral 20 denotes a package body, which is formed by stacking and firing green sheets and has a wiring pattern formed therein (not shown). Reference numeral 21 denotes an external connection pin that is connected to the internal wiring pattern and is brazed to the package body 20. The internal wiring pattern is the package body 20
The exposed pattern is exposed on the internal step, and a wire is connected between the exposed pattern and the semiconductor element 23 mounted on the heat sink 22. Heat sink 22
Is brazed to the package body 20 while covering the central through hole of the package body 20.

As shown in FIG. 2, the heat sink 22 is integrally formed of a sintered metal having a different thermal expansion coefficient at the mounting portion of the semiconductor element and the joint portion to the package body, and is brazed to the package body 20. Is formed in the sintered metal A having a coefficient of thermal expansion (7.0 to 8.0 × 10 ⁻⁶ / ° C.) close to that of the ceramic of the package body 20, and the heat of the portion where the semiconductor element 23 is mounted. The thermal expansion coefficient of the semiconductor element 23 is Si (3.4 × 10 ^-6 /
C) and the thermal expansion coefficient (3.5 to 6.0 × 10 ⁻⁶ / ° C.) of the sintered metal B. The material configuration of the heat sink 22 is preferably the following configuration. That is, the sintered metal A that is to be bonded to the package body is Cu-W, Cu-
Mo or Cu-Ni-W system sintered metal, Cu
Content of 10 to 15%. In addition, the sintered metal B on the semiconductor element mounting side has a W content of Cu of 0 to 10%.
A Cu-based or Mo-Cu-based material having a Cu content of 0 to 10% is used. By adopting the above-mentioned material configuration, the matching of the thermal expansion coefficient as described above can be achieved.

The above-mentioned sintered metal having a one-piece structure and partially different in coefficient of thermal expansion was manufactured as follows. As shown in FIG. 3, powder molding plates A layer, C layer, and B layer having different ratios of copper powder and tungsten powder were laminated and sintered to be integrated. A: 85:15 W: Cu, C: 9
It is a powder molded plate which is compressed into a plate shape by adjusting the layer B at 0:10 and 95: 5. By laminating and sintering in this way, the interfaces between them were also bound to form a sintered metal having an integral structure. In this way, by forming powder molding plates with different mixing ratios in advance, and stacking and sintering this,
Although there was some migration of the metal between the layers, a sintered metal was obtained in which the original ratio was maintained and the compounding ratio was gradually changed on the front and back surfaces. The thermal expansion coefficient of the A layer having a large amount of copper powder has a thermal expansion coefficient close to that of the ceramic package body 20, and the thermal expansion coefficient of the B layer having a small amount of copper powder close to that of the semiconductor element. have. The sintered body thus formed was cut to form a heat sink having the shape shown in FIG. 2, and this was brazed to the separately formed package body 20 to form a package. The semiconductor element 23 is mounted on the heat sink 22 to complete a semiconductor device. No warp was found in the heat sink 22 and no crack was generated in each part.

In the above-mentioned examples, the powder molding plates having different compounding ratios were sintered into three layers. However, better results were obtained by using four or more layers having different compounding ratios in stages. . Further, although the W-Cu type is shown in the above-mentioned examples, similar results were obtained also with the W-Mo type. See also W
The -Ni-Cu system was also good. In this case, since the semiconductor element mounting part is adjusted to the required coefficient of thermal expansion, WC
I made it u type.

In the above-mentioned embodiment, the type having the through hole in the package body is shown, but as shown in FIG.
The heat sink 22 may be of a type that is brazed onto the element housing hole of the package body 20. Although the PGA (pin grid array) type is described in this embodiment, it is needless to say that the present invention can be widely applied to a ceramic package having a heat sink other than PGA.

[0012]

According to the ceramic package for a semiconductor device of the present invention, the heat sink is an integral sintered metal having different thermal expansion coefficients on the front and back sides, and the thermal expansion coefficient of the joint portion to the package body is the package body. Since the one having a thermal expansion coefficient similar to that of the above-mentioned ceramics and the thermal expansion coefficient of the semiconductor element mounting portion similar to that of the semiconductor element is used, the heat sink does not warp and the mounted semiconductor is mounted. A package that does not adversely affect the device can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a semiconductor device ceramic package according to the present invention.

FIG. 2 is a sectional view of the heat sink.

FIG. 3 is a cross-sectional view showing a manufacturing example of a heat sink.

FIG. 4 is a sectional view showing another embodiment.

FIG. 5 is a cross-sectional view showing an example of a conventional semiconductor device package.

[Explanation of symbols]

 20 Package Body 21 Pin 22 Heat Sink 23 Semiconductor Element

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 23/373 9355-4M H01L 23/12 F 23/36 M

Claims (2)

[Claims] 1. A ceramic package for a semiconductor device, wherein a metal heat sink is joined to a ceramic package body, and a semiconductor element is mounted on the heat sink, wherein the heat sink is formed by integrally sintering. The coefficient of thermal expansion differs between the junction with the package body and the mounting area of the semiconductor element, and the thermal expansion coefficient of the junction with the package body is about the same as that of the package body. A ceramic package for a semiconductor device, which has a thermal expansion coefficient similar to that of a mounted semiconductor element. 2. The heat sink has a Cu-W, Cu-Mo or Cu-Ni-W joint portion with a package body.
System sintered metal with a Cu content of 10 to 15%, and the semiconductor element mounting portion has a Cu content of 0 to 10% W-Cu system or a Cu content of 0 to 10% Mo-. The ceramic package for a semiconductor device according to claim 1, wherein the ceramic package is a Cu-based sintered metal.