JP2014093389A - Pressure contact semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure contact semiconductor device capable of surely preventing local concentration of current between an electrode member and a semiconductor element.SOLUTION: A pressure contact semiconductor device 1 comprises a semiconductor element 2, a pressure member 3, and an electrode member 4 brought into pressure contact with a surface of the semiconductor element 2 by the pressure member 3. The electrode member 4 comprises a plurality of salients 5 which are uniformly arranged on the surface thereof and can penetrate an oxide layer 2a of the semiconductor element 2, and a plane part 6 formed surrounding the salients 5.

Description

  The present invention relates to a pressure contact semiconductor device.

  Conventionally, a semiconductor device in which a semiconductor element mounted on a substrate or the like is connected to a power feeder via a wire is known. There is also known a pressure contact type semiconductor device in which both front and back surfaces of a semiconductor element are sandwiched between electrode members, and the electrode members are pressed to be brought into pressure contact with the semiconductor elements.

  In the pressure-contact type semiconductor device, the electrode member is considered to be energized by surface contact with the semiconductor element, but in reality, it is a set of point contacts due to minute protrusions on the surface of the electrode member. As a result, in the pressure contact type semiconductor device, contact with the semiconductor element becomes non-uniform depending on the surface state of the electrode member, and when current is concentrated locally, Joule heat is generated in the part and the semiconductor element is destroyed. There is a problem that.

  Therefore, in order to solve the above problem, a pressure contact type semiconductor device has been proposed in which irregularities are regularly provided on the surface of the electrode member to prevent current from being concentrated locally (for example, Patent Document 1).

International Publication No. 99/12197

  However, in the pressure contact type semiconductor device in which the irregular surface is regularly provided on the surface of the electrode member, there is a disadvantage that local current concentration cannot be sufficiently prevented.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pressure contact type semiconductor device that can eliminate such inconvenience and reliably prevent local current concentration between an electrode member and a semiconductor element.

  The inventors of the present invention have made extensive studies on the reason why local current concentration cannot be sufficiently prevented in a press-contact type semiconductor device in which irregular surfaces are regularly provided on the surface of the electrode member. As a result, when the convex portion is present on the entire surface of the electrode member, it seems that the current value per convex portion is seemingly dispersed and advantageous, but the load applied to one convex portion is actually reduced, It has been found that this causes problems in current distribution.

  That is, the convex portion is pressed against the surface of the semiconductor element, thereby destroying and penetrating the oxide film formed on the surface, thereby reducing the contact resistance of the portion and conducting the semiconductor element. Can be secured. However, if the load is insufficient and the convex portion cannot sufficiently penetrate the oxide film, the ease of current flow becomes uneven. If the load is increased, the oxide film can be passed through the convex portion. However, if the load is excessive, the semiconductor element may be destroyed, and the adjustment of the load becomes difficult.

  Therefore, the present inventors have further studied based on the above findings and have reached the present invention. In order to achieve the above object, the present invention provides a pressure contact type semiconductor comprising a semiconductor element, a pressure member, and an electrode member that is pressed against the surface of the semiconductor element by the pressure member to be energized. In the apparatus, the electrode member is uniformly disposed on a surface pressed against the surface of the semiconductor element, and has a plurality of protrusions capable of penetrating an oxide film formed on the surface of the semiconductor element, and the protrusions And a flat surface portion formed so as to surround.

  In the pressure-contact type semiconductor device of the present invention, the electrode member includes a plurality of convex portions that are uniformly arranged on a surface that is in pressure contact with the surface of the semiconductor element, and a plane portion that surrounds the convex portions. The convex portion is formed so as to be able to penetrate the oxide film on the surface of the semiconductor element.

  Here, since the periphery of the convex portion is surrounded by the flat portion, the number per unit area is small compared to the case where the irregular surface is regularly provided on the surface of the electrode member. The load per hit increases. Therefore, the convex portion can surely penetrate the oxide film. The planar portion acts as a stopper when the convex portion penetrates the oxide film, and suppresses the penetration of the convex portion into the semiconductor element. Accordingly, it is possible to prevent the semiconductor element from being broken due to the protrusions entering the semiconductor element excessively.

  As a result, according to the press-contact type semiconductor device of the present invention, each of the convex portions reliably penetrates the oxide film with a smaller load, so that conduction between the electrode member and the semiconductor element can be ensured. The current can be supplied uniformly to the semiconductor element.

  In the press contact type semiconductor device of the present invention, it is preferable that the convex portions are uniformly arranged with a center-to-center distance of 10 to 500 μm. When the distance between the centers of the convex portions is less than 10 μm, the load per convex portion may not be sufficiently increased, and the flat portion may not sufficiently function as a stopper. In addition, when the distance between the centers of the protrusions exceeds 500 μm (0.5 mm), there may be a case where a function of uniformly supplying current to the semiconductor element cannot be obtained sufficiently.

  In the press contact type semiconductor device of the present invention, it is preferable that the convex portion has a conical shape. The cone shape may be a cone shape or a pyramid shape. Since the convex portion has a conical shape, the tip end portion thereof is sharp, so that the oxide film can be advantageously penetrated. Moreover, since the convex portion has a conical shape, the base portion thereof has a larger cross-sectional area, and the resistance increases as it penetrates into the semiconductor element, so that excessive penetration can be suppressed. Further, when the load is uneven, it is possible to obtain an effect of making the load uniform.

  In the pressure contact type semiconductor device of the present invention, it is preferable that the electrode member is formed by electroforming using a mold having a concave portion having a shape along the surface shape of the convex portion. By forming the electrode member by the electroforming method, it is possible to easily obtain good reproducibility of the shape even if the shape of the convex portion is fine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory cross-sectional view illustrating a configuration example of a pressure contact type semiconductor device according to the present invention. The top view which shows the surface of the electrode member shown in FIG. The enlarged view of the convex part shown in FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory cross-sectional view illustrating a configuration example of a pressure contact type semiconductor device according to the present invention.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  As shown in FIG. 1, the press contact type semiconductor device 1 of the present embodiment includes a semiconductor element 2, a pressure member 3 disposed on both front and back surfaces of the semiconductor element 2, and the surface of the semiconductor element 2 by the pressure member 3. And an electrode member 4 which is brought into a state where it can be energized.

  The electrode member 4 is made of a highly conductive metal such as copper, and is provided integrally with the pressure member 3 on the surface of the pressure member 3 facing the semiconductor element 2. The electrode member 4 includes a plurality of convex portions 5 that are uniformly arranged on a surface that is in pressure contact with the surface of the semiconductor element 2, and a flat portion 6 that is formed to surround the convex portions 5.

  As shown in FIG. 2, the convex portions 5 are uniformly formed with a center distance D between them, and the center distance D can be appropriately adjusted within a range of 10 to 500 μm. At this time, all the portions other than the portions where the convex portions 5 on the surface of the electrode member 4 are formed are the flat portions 6 surrounding the convex portions 5. The convex portion 5 has a regular quadrangular pyramid shape as shown in an enlarged view in FIG. 3A, and the length d of one side thereof is, for example, 10 μm as shown in FIG. The height h is 5 μm, for example.

  The electrode member 4 including the convex portion 5 having the shape can be formed by electroforming using, for example, a mold including a concave portion having a shape along the surface shape of the convex portion 5.

  Next, the operation of the pressure contact type semiconductor device 1 of the present embodiment will be described.

  In the press-contact type semiconductor device 1 of the present embodiment, as shown by an arrow in FIG. 1, the surface of the electrode member 4 on which the convex portion 5 is formed is formed on the surface of the semiconductor element by pressing the electrode member 4 with the pressing member 3. 2 is pressed. In this way, as shown in FIG. 4, the convex part 5 having a regular quadrangular pyramid shape with a sharp tip penetrates the oxide film 2a formed on the surface of the semiconductor element 2, and the electrode member 4 and the semiconductor are formed. Conduction with the element 2 is ensured.

  At this time, the plurality of convex portions 5 are uniformly formed with the distance D between the centers therebetween, and the periphery thereof is surrounded by the flat portion 6. Therefore, since the number of the convex parts 5 per unit area is small and the load per one convex part 5 becomes large compared with the case where the irregular surface is regularly provided on the surface of the electrode member 4, the convex parts 5 The oxide film 2a can be reliably penetrated. Further, since the flat portion 6 acts as a stopper when the convex portion 5 penetrates the oxide film 2a and suppresses excessive penetration of the convex portion 5 into the semiconductor element 2, it is possible to prevent the semiconductor element 2 from being broken. it can.

  As a result, according to the press contact type semiconductor device 1 of the present embodiment, a current can be supplied uniformly to the semiconductor element 2 without concern about adjustment of the load.

  In the present embodiment, the convex portion 5 has a regular quadrangular pyramid shape. However, the convex portion 5 may have a conical shape or a pyramid shape other than the regular quadrangular pyramid, and has a shape that can penetrate the oxide film 2a. Any shape may be used.

  DESCRIPTION OF SYMBOLS 1 ... Pressure-contact type semiconductor device, 2 ... Semiconductor element, 2a ... Oxide film, 3 ... Pressure member, 4 ... Electrode member, 5 ... Convex part, 6 ... Plane part.

Claims (4)

In a pressure-contact type semiconductor device comprising a semiconductor element, a pressure member, and an electrode member that is pressed against the surface of the semiconductor element by the pressure member to be energized,
The electrode member is uniformly disposed on a surface that is pressed against the surface of the semiconductor element, and a plurality of convex portions that can penetrate an oxide film formed on the surface of the semiconductor element;
A press contact type semiconductor device comprising: a flat portion formed surrounding the convex portion.   2. The pressure-contact type semiconductor device according to claim 1, wherein the convex portions are uniformly arranged with a center-to-center distance of 10 to 500 [mu] m from each other.   3. The pressure-contact type semiconductor device according to claim 1, wherein the convex portion has a conical shape.   4. The press-contact type semiconductor device according to claim 1, wherein the electrode member is formed by an electroforming method using a mold including a concave portion having a shape along a surface shape of the convex portion. A pressure contact type semiconductor device characterized by the above.