JPS594032A - Pressure welding type semiconductor device - Google Patents

Abstract

PURPOSE:To equalize stress distribution in a semiconductor element base body by interposing a metallic plate for dispersing pressure, a peripheral section thereof is thicker than a central section, between a point-contact jig and the base body when metallic stamps and cooling fins are each stacked to both surfaces of the base body and a pressure plate is set up onto the cooling fin through the point-contact jig. CONSTITUTION:A temperature-compensating plate 11 in Mo, etc. is brought into contact with one surface of the semiconductor element base body 10, and a mechanical support plate 12 in W, etc. is brought into contact with the other surface. The cooling fins 15, 16 in Al are each set up to the outsides of the plates through the electrode metallic stamps 13, 14, and a base body 10 section is surrounded by a package 22. A lower pressure plate 21 is mounted on the fin 16 side through an insulating plate 18, and the pressure plate 20 is also mounted on the fin 15 side through an insulating plate 17 and the point-contact jig 19, but the metallic plate 41 for dispersing pressure, the peripheral section thereof is thicker than the central section, is inserted previously between the fin 15 and the insulating plate 17 in addition to the installation of the pressure plate 20. Accordingly, force concentrating to the jig 19 is re-dispersed, and stress is made uniform.

Description

[Detailed description of the invention] [-Technical field of invention] The present invention relates to a pressure contact type semiconductor device ζ2.

[Technical background of the invention and its problems]

With the development of power semiconductor devices, the number of press-contact type semiconductor devices has increased. The main purpose of this is to use a pressurized contact type to radiate heat from two surfaces of the semiconductor element in order to suppress heat generation due to power loss occurring within the semiconductor substrate.

When a pressure contact type semiconductor device is put into practical use, it is common to assemble a semiconductor stack consisting of many components as shown in FIG. In FIG. 1, one surface of a semiconductor element substrate 10 is brought into contact with a temperature compensation plate 11 made of, for example, molybdenum, and the other surface is brought into contact with a mechanical support plate I2 made of tungsten or the like. Electrode metal stamps 7 on the outside of these two plates 11.12, ? , 14 are provided with cooling fins 15, 16 each consisting of A/etc. 2
2 is an envelope. Further, one cooling fin 15 is brought into contact with the pressure plate 2θ via an insulating plate 17 and a point contact jig 19 made of steel or the like, and the other cooling fin 16 is brought into contact with the pressure plate 2θ via a natural edge plate 18.
contact with. The lower pressure plate 2 normally serves as a fixed plate during pressurization, and by applying force in the direction of the arrow from the upper pressure plate 20 side, the semiconductor element substrate 10 is electrically and thermally connected to the outside. . This structure is called a semiconductor stack.

The purpose of the point contact jig I9 shown in Figure 1 will be explained using Figure 2. A semiconductor element substrate 30 is attached to a metal stamp 31 and an insulator 3.
2. When considering a pressure stud consisting of a point contact jig 33 and a pressure plate 34, the bottom surface of the pressure plate 34, that is, the point contact jig 3.
? Side force: Even in the case of υ1 in a plane perpendicular to the axis (c-c') as shown in the figure, the force is transmitted at one point so that uneven pressure is not applied to the semiconductor element substrate 30. This is the purpose of the point contact jigs 3 and 9.

By the way, in the stack configured as shown in FIG. 1, the in-plane stress of the semiconductor element substrate 10. When we actually measured the cloth, it looked like the one shown in Figure 3. A solid line A is the stress distribution near the surface of the semiconductor element substrate 10 on the side in contact with the temperature compensating plate 11, and a solid line B is the stress distribution at the interface between the cooling fins 15 and the insulating plate 17. R8 along the horizontal axis is the radius of the temperature compensation plate 11.

As shown in the figure, the stress at the center (X:0) of both A and B is extremely high. This is because the point contact jig I9 shown in FIG. 1 receives and transmits force from the outside at one point, so the force is concentrated at the center. Moreover, when two stresses are concentrated, the thermal resistance may be partially exceeded or power may be concentrated, which ultimately leads to the destruction of the semiconductor element substrate.

[Purpose of the invention]

In view of the above-mentioned points, the present invention provides a press-contact type semiconductor device in which the stress distribution within the semiconductor substrate is made uniform and the reliability is improved.

[Summary of the invention]

The present invention provides a semiconductor stack such as the one shown in FIG. 1 in which the peripheral portion is thicker than the center between the point contact jig and the semiconductor element substrate, and deformation occurs when pressure is applied to the semiconductor element substrate. A pressure dispersion member is interposed to make the stress distribution uniform.

〔Effect of the invention〕

According to the present invention, the internal stress of the semiconductor substrate is made uniform, and
It is possible to prevent damage caused by power concentration and increased thermal resistance due to partial contact, and to improve the reliability of the press-contact type semiconductor device.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a cross-sectional view of one embodiment of the present invention (a metal plate 41 as a pressure dispersion member in FIG. 2 (a)), and FIG. 4 (h) is a plan view. As shown in the figure, the metal plate 41 is thicker at the periphery than at the center. , the difference in thickness between the peripheral part and the middle part is 30 to 40 (
(μm) XI) As shown in FIG. 5, the metal plate 41 having a non-uniform thickness made in this way is inserted between the insulating plate 17 and the cooling fins 15, and is moved in the direction of the arrow 1 from the top of the figure.
''' - Pressure is applied. In addition, in Figure 5, 6
The same parts as in FIG. 1 are given the same reference numerals. When the force passes through the point contact jig 17, it is concentrated at the center of the axis (C-C'), but due to the thick peripheral edge of the metal plate 41, the force is transferred to the center I) It becomes secret. As a result, the force concentrated at the point contact jig 19 is again dispersed and made uniform, so that the in-plane C21
A new and uniform force will be lost.

Figure @6 shows the measurement of the compressive stress at the interface between the temperature compensation plate 11 and the semiconductor element substrate IO according to this embodiment. As shown in the figure, a fairly uniform stress distribution was obtained.

When constructing the stack of the present invention, the pressure dispersion member may be inserted anywhere between the point contact jig and the semiconductor element substrate, without being limited to between the insulating plate and the cooling fin.

FIGS. 7fa) and 7(b) are a sectional view and a plan view of a pressure dispersion member according to another embodiment of the present invention, which is constructed by stacking three metal rings with different inner diameters.1. ing. As shown in the figure, the present invention also includes a structure in which there is no metal in the center.

FIGS. 8A and 8B are a sectional view and a plan view of a pressure dispersion member according to another embodiment, and both sides may be concave as shown in the cross section of FIG.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional semiconductor stack, Figure 2 is a diagram for explaining the function of the point contact jig, and Figure 3 is a diagram showing the in-plane stress distribution of a semiconductor element substrate in a conventional semiconductor stack. , FIG. 4(b) is a diagram showing a metal plate as a pressure dispersion residue material used in one embodiment of the present invention, FIG. 5 is a configuration diagram of a semiconductor stack of the same embodiment, and FIG. 6 is a diagram showing the same. A diagram showing in-plane stress distribution within a semiconductor element substrate according to an example,
Figure 7 (al, (bl) and Figure 8 (a), (
bl is a diagram showing a pressure dispersion member according to another embodiment of the present invention. 10... Semiconductor element substrate, 11... Temperature compensation plate, 1
2... Support plate, 1.9, Z 4... Metal stamp, 15°16... Cooling fin, 17. IFt...
Insulating plate, 19...point contact jig, 20.21...addition!
King plate, 22... Envelope, 4)... Metal plate (pressure dispersion member). Substitution for application Patent attorney Rin Ushiki Hiko Figure 1 Figure 8 154- (a) (b)

Claims (1)

[Claims] In a pressure contact type semiconductor device, which is constructed by laminating metal stamps and cooling fins on both sides of a semiconductor element substrate, and further laminating a pressure plate on these laminated bodies via a point contact jig,
A pressure dispersion member is interposed between the point contact jig and the semiconductor element substrate, the peripheral part of which is thicker than the central part, and which deforms when pressurized to uniformize the in-plane stress distribution to the semiconductor element. A press-contact type semiconductor device characterized by: