JP4882495B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which a circuit board on which a semiconductor element is mounted is accommodated in a resin case.

  In recent years, a semiconductor device (referred to as a power module or intelligent power module) in which a semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) having a low loss and a large breakdown resistance is mounted on a circuit board and stored in a resin case. It is applied to power converters such as inverters and uninterruptible power supplies.

4A and 4B are views showing the appearance of a conventional semiconductor device, in which FIG. 4A is a perspective view and FIG. 4B is a top view.
The semiconductor device 50 includes a resin case 51 that houses a circuit board (not shown) on which a semiconductor element such as an IGBT is mounted. On the resin case 51, a plurality of lead pins 52 and terminals 53 drawn from the terminal portions of the internal circuit board are provided. A through hole 54 is formed in the resin case 51, and a cylindrical metal member 55 that is integrally formed with the resin case 51 is embedded in the through hole 54.

FIG. 5 is a cross-sectional view taken along line AA in FIG.
In the conventional semiconductor device 50, the cylindrical metal member 55 is provided with the same length as the depth of the through hole 54, that is, the thickness of the resin case 51.

A bolt (not shown) is passed through the cylindrical metal member 55, and a metal base 56 for heat dissipation is attached to the resin case 51 together with a cooling fin (not shown). By providing such a cylindrical metal member 55, the outer wall of the through hole 54 is reinforced, and the resin case 51 can be prevented from cracking when the bolt is tightened (see, for example, Patent Document 1).
JP-A-8-162572

  However, in the conventional semiconductor device, the cylindrical metal member 55 as shown in FIG. 5 is provided with the same depth as the depth of the through hole 54, that is, the thickness of the resin case 51. Sometimes, resin burrs generated sometimes adhere to the upper surface of the cylindrical metal member 55 like a thin skin. If the bolt is tightened with such a resin cover, the bolt loosens due to a long-term temperature cycle and the heat dissipation characteristics deteriorate.

  The present invention has been made in view of such a point, and an object thereof is to provide a semiconductor device capable of reducing loosening when a resin case and a heat radiating member are tightened with a bolt.

  In the present invention, in order to solve the above problem, in a semiconductor device in which a circuit board on which a semiconductor element is mounted is accommodated in a resin case, the resin case is embedded in a through hole formed in the resin case. It has a cylindrical metal member, one end of the cylindrical metal member protrudes from the through hole, and a step is formed at the end of the protruding cylindrical metal member whose center side is higher than the outer peripheral side. A semiconductor device is provided.

  According to the above configuration, the cylindrical metal member embedded integrally with the resin case in the through hole of the resin case has one end protruding from the through hole, and the center side is the outer periphery at the end of the protruding cylindrical metal member Since the step which is higher than the side is formed, the upper surface on the center side of the cylindrical metal member is suppressed from being covered with the resin burr.

  In the semiconductor device of the present invention, the cylindrical metal member embedded integrally with the resin case in the through hole of the resin case is protruded from the through hole, and the center side is higher than the outer peripheral side at the end of the protruding cylindrical metal member Since the step is formed, it is possible to suppress the upper surface on the center side of the cylindrical metal member from being covered with the resin burr. Thereby, the looseness at the time of fastening a resin case and a heat radiating member with a volt | bolt can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1A and 1B are external views of the semiconductor device of this embodiment, where FIG. 1A is a perspective view and FIG. 1B is a top view.

  The semiconductor device 10 of the present embodiment has a resin case 11 that houses a circuit board (not shown) on which a semiconductor element such as an IGBT is mounted. On the resin case 11, a plurality of lead pins 12 drawn out from terminal portions of an internal circuit board and terminals 13 are provided. Further, a through hole 14 is formed in the resin case 11, and a cylindrical metal member 15 integrally formed with the resin case 11 is embedded in the through hole 14. This through hole 14 is a hole for inserting a bolt when attaching a metal base for heat dissipation or a cooling fin to the resin case 11. The cylindrical metal member 15 reinforces the outer wall of the through hole 14 and prevents the resin case 11 from cracking when the bolt is tightened.

FIG. 2 is a cross-sectional view taken along line AA in FIG.
Unlike the conventional case, the cylindrical metal member 15 of the present embodiment has one end protruding from the through hole 14, and a step that is higher on the center side than the outer peripheral side is formed at the end of the protruding cylindrical metal member 15. Yes. A bolt (not shown) is passed through such a cylindrical metal member 15, and a metal base 16 for heat dissipation is attached to the resin case 11 together with a cooling fin (not shown).

The following effects can be obtained by projecting the cylindrical metal member 15 from the through hole 14 and providing the step as described above.
FIG. 3 shows a state of a bolt mounting portion when a resin burr is generated. (A) shows a case where a cylindrical metal member having no step is used, and (B) shows a cylindrical metal member having a step. It is a figure which shows the case where is used.

  Here, similarly to FIG. 2, a cross-sectional view taken along line AA of FIG. However, the cylindrical metal member 15a shown in FIG. 3A is not provided with a step like the cylindrical metal member 15 of FIG. When the cylindrical metal member 15a that protrudes from the through hole 14 and has no step is used, the resin burr 20 that extends vertically is likely to be generated, and it may wrap around the upper surface of the cylindrical metal member 15a. In that case, the bolt may be tightened with the resin sandwiched, and the bolt may be loosened due to a temperature cycle or the like.

  On the other hand, as shown in FIG. 3B, one end of the cylindrical metal member 15 is protruded from the through hole 14 of the resin case 11, and the center side is provided with a step that is higher than the outer peripheral side, thereby extending vertically. Burrs are less likely to occur. Even when the resin burr 21 that extends sideways is generated, the resin burr 21 is unlikely to wrap around the upper surface of the cylindrical metal member 15 because of the level difference. That is, it is possible to prevent the upper surface on the center side of the cylindrical metal member 15 from being covered with the resin burr 21. Thereby, the looseness at the time of fastening the resin case 11, the metal base 16, and the cooling fin with the bolt can be reduced, and deterioration of the heat dissipation characteristics can be prevented.

  In addition, since the influence of the resin burr 21 at the time of tightening the bolt can be reduced, the molding operation for removing the resin burr 21 can be made more efficient.

2A and 2B are diagrams illustrating an appearance of a semiconductor device of the present embodiment, where FIG. 3A is a perspective view and FIG. It is sectional drawing in the AA line of FIG. 1 (B). When the resin burr | flash generate | occur | produces, the mode of the attachment part of the volt | bolt is shown, When (A) uses the cylindrical metal member without a level | step difference, (B) uses the cylindrical metal member with a level | step difference FIG. It is a figure which shows the external appearance of the conventional semiconductor device, (A) is a perspective view, (B) is a top view. It is sectional drawing in the AA line of FIG. 4 (B).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor device 11 Resin case 12 Lead pin 13 Terminal 14 Through-hole 15, 15a Cylindrical metal member 16 Metal base 20, 21 Resin burr

Claims (2)

In a semiconductor device in which a circuit board on which a semiconductor element is mounted is stored in a resin case,
In a through hole formed in the resin case, a cylindrical metal member embedded in the resin case and integrally molded,
One end of the cylindrical metal member protrudes from the through hole, and a step having a higher center side than the outer peripheral side is formed at the end of the protruding cylindrical metal member. The semiconductor device according to claim 1, wherein the through hole is a bolt insertion hole when a heat dissipation member is attached to the resin case.

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