JP2014229649A - Semiconductor module and manufacturing method thereof - Google Patents

Abstract

Bubble generation is suppressed when potting a semiconductor element with a resin. A case includes a heat-dissipating base plate and a peripheral wall standing on the periphery of the base plate. A base 17 including the ceramic substrate 11 and the metal layers 13 and 15 is disposed on the base plate 3 inside the peripheral wall 5, and the power semiconductor element 23 is mounted on the base 17. The peripheral wall 5 is provided with a vent hole 39 extending in the vertical direction, and the lower portion of the vent hole 39 communicates with the bottom of the case 7 through the communication portion 39b. The communication portion 39 b opens in the case 7 over the entire circumference of the peripheral wall 5. [Selection] Figure 1

Description

  The present invention relates to a semiconductor module in which a semiconductor element placed in a case is potted with a resin and sealed, and a method for manufacturing the same.

  Conventionally, there has been a semiconductor module in which a ceramic substrate having a metal layer on which a semiconductor element is mounted is disposed on a base board for heat dissipation, and the inner ceramic substrate and the semiconductor element surrounded by a case side wall are potted and sealed with epoxy resin. It is known (see Patent Document 1 below).

JP 2006-179732 A

  By the way, the above-mentioned potting resin has a relatively high viscosity. Therefore, bubbles are easily generated in the lower part of the case in a state where air is trapped by the resin, and improvement is desired.

  Accordingly, an object of the present invention is to suppress the generation of bubbles when potting a semiconductor element with a resin.

  The present invention is a semiconductor module having a structure in which a semiconductor element disposed in a case is potted and sealed with a resin, and the side wall of the case includes a vent hole extending in a vertical direction. It communicates with the bottom of the case.

  According to the present invention, when the semiconductor element is potted with resin, the air pushed into the lower part by the injected resin is released to the outside through the vent hole, so that the generation of bubbles confined by the resin is suppressed. be able to.

FIG. 1 is a cross-sectional view of a power semiconductor module according to an embodiment of the present invention. FIG. 2 is a plan view showing a part of the side wall of the case in the power semiconductor module of FIG. 3 is a cross-sectional view taken along the line CC of FIG. FIG. 4 is a plan view corresponding to FIG. 2, showing a more specific shape of the case. 5 is a cross-sectional view taken along the line DD of FIG. 6 is a cross-sectional view taken along line EE in FIG. 7A is a cross-sectional view taken along line FF in FIG. 4, and FIG. 7B is a cross-sectional view illustrating a modification of FIG. 7A. FIG. 8 is a cross-sectional view showing a state where an epoxy resin is potted in a region in the case of the power semiconductor module of FIG. FIG. 9 is a cross-sectional view showing a comparative example with respect to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a power semiconductor module 1 as a semiconductor module according to an embodiment of the present invention. The power semiconductor module 1 includes a base plate 3 for heat dissipation composed of a metal such as an aluminum alloy. A cooling water passage 3 a through which cooling water flows is provided in the base plate 3. The base plate 3 has a rectangular shape in plan view, and a peripheral wall 5 is provided on the outer peripheral side upper surface of the base plate 3, and the base plate 3 and the peripheral wall 5 constitute a case 7.

  In the inner region 9 surrounded by the peripheral wall 5 on the base plate 3, a base 17, which is a composite substrate provided with metal layers 13 and 15 made of copper or the like on both upper and lower sides of the ceramic substrate 11, an insulating layer 19 is provided. Is arranged through. A power semiconductor element 23 is mounted on the upper metal layer 13 via solder 21. A semiconductor module main body 25 is configured including the pedestal 17 and the power semiconductor element 23 above the pedestal 17.

  FIG. 2 is a plan view showing a part of the peripheral wall 5 of the case 7, and the entire shape of the case 7 is a rectangular shape that is long in the vertical direction in FIG. 2, and in its longitudinal direction (vertical direction in FIG. 2). The above-described region 9 corresponding to three phases (U phase, V phase, and W phase) is formed along. In FIG. 2, the semiconductor module main body 25 disposed in the region 9 is omitted.

  The peripheral wall 5 of the case 7 includes a pair of left and right long side portions 27 in a rectangular shape that is long in the vertical direction in FIG. 2 and a pair of short side portions 29 located on both the upper and lower sides in FIG. Are omitted). Further, each region 9 for three phases (U phase, V phase, W phase) is partitioned by a partition wall portion 31 parallel to the short side portion 29. The peripheral wall 5 (long side portion 27, short side portion 29) and partition wall portion 31 described above constitute the side wall of the case 7.

  On the upper surface of one long side 27 on the right side in FIG. 2, power supply terminals 33 and 35 connected to an external bus bar (not shown) are provided for each of U, V, and W phases. 2, U, V, and W terminals 37 connected to other external bus bars (not shown) are provided for the respective phases on the upper surface of the other long side portion 27 on the left side. An insert nut (not shown) that is electrically connected to each of the terminals 33, 35, and 37 is embedded in the long side portion 27. The electrical connection structure between the insert nut and the base 17 side is omitted.

  And in this embodiment, the vent hole 39 extended so that it may penetrate in the up-down direction in the surrounding wall 5 is formed. As shown in FIG. 2, the ventilation holes 39 here are provided at two locations on the pair of long side portions 27 of the peripheral wall 5 corresponding to each phase of U, V, and W, respectively, and on the short side portion 29 of the peripheral wall 5. Are provided in three places. In FIG. 2, the vent holes 39 are not provided in the partition wall 31, but can be provided in the partition wall 31. The cross-sectional structure of the left and right long side portions 27 of the peripheral wall 5 in FIG. 1 corresponds to the AA cross section in FIG. 2 on the left side in FIG. 1, and the BB cross section in FIG. Corresponds to the figure.

  As shown in FIG. 1, the vent hole 39 includes an opening 39 a serving as an air discharge port on the upper surface of the peripheral wall 5, and a lower portion communicates with a bottom portion of the region 9 in the case 7 via a communication portion 39 b. The communication portion 39 b communicates with the lower portions of the plurality of vent holes 39 and is continuously formed over the entire circumference on the inner peripheral side of the peripheral wall 5 (long side portion 27, short side portion 29) and the partition wall portion 31.

  As shown in the cross-sectional structure corresponding to the line BB in FIG. 2 (the long side portion 27 on the right side in FIG. 1), the communication portion 39 b is directly connected to the region 9 in the case 7 and opens to the opening 39 b 1. And a communication passage 39b2 positioned above the opening 39b1 at a position opposite to the region 9 of the opening 39b1. The communication path 39b2 communicates the lower portions of the adjacent vent holes 39 with each other. Such an opening 39b1 and the communication path 39b2 can be formed by providing a projection 39c that projects a portion of the peripheral wall 5 on the region 9 side downward. The protrusion 39 c is provided continuously over the entire circumference on the inner peripheral side of the peripheral wall 5 (long side portion 27, short side portion 29) and the partition wall portion 31. That is, by providing the protrusion 39c over the entire circumference in this way, the opening 39b1 is formed over the entire circumference.

  3 is a cross-sectional view taken along the line C-C in FIG. 2, and the communication path 39 b 2 directly communicates the adjacent vent holes 39 with each other. Further, as shown in FIG. 3, the vent hole 39 has a tapered shape such that the opening 39a side is narrow and the communicating portion 39b side is wide.

  4 to 7 show a more specific shape of the case 7, and the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. FIG. 4 corresponds to FIG. 2, but is a view rotated 90 degrees in the clockwise direction on the paper with respect to FIG. 2. However, FIG. 4 and FIG. 2 differ in that the power supply terminals 33 and 35 and the U, V, and W terminals 37 are provided on the long side portions 27 on the opposite sides. In FIG. 4, a vent hole 39 is also provided in the partition wall 31.

  5 is a sectional view taken along the line DD of FIG. 4, and FIG. 6 is a sectional view taken along the line EE of FIG. 4. The lower part of the peripheral wall 5 (long side portion 27, short side portion 29) is shown in FIGS. It can be seen that an opening 39b1 extending in the left-right direction is formed. Further, as shown in FIG. 5, it can be seen that a communication path 39b2 is formed below the short side portion 29 and the partition wall portion 31 so as to communicate with the opening 39b1 and to be positioned above the opening 39b1.

  7A is a cross-sectional view taken along the line F-F in FIG. 4. In the lower part of the long side portion 27 in the peripheral wall 5, the back side of the opening 39 b 1 in FIG. It can be seen that an extended communication path 39b2 is formed. The communication passage 39b2 directly communicates the lower portions of the adjacent vent holes 39 with each other.

  FIG. 7B is a modification of FIG. 7A, and a pair of left and right inclined surfaces 39b3 are formed on the lower surface of the upper wall in the communication passage 39b2. The pair of inclined surfaces 39b3 are inclined so that the air hole 39 side is upward with respect to the substantially central position S between the air holes 39 adjacent to each other along the circumferential direction of the peripheral wall 5 of the case 7. That is, the lower end opening of the vent hole 39 is located above the center position S.

  Next, the operation will be described. As shown in FIGS. 1 and 2, the semiconductor module body 25 in the region 9 surrounded by the peripheral wall 5 and the partition wall 31 is sealed by potting with an epoxy resin 41 as shown in FIG. Since the epoxy resin 41 used for such potting is relatively high in clay, air is trapped inside by the resin in the process of filling the region 9 with the resin, and the vent holes 39 are formed as shown in FIG. As shown in the comparative example which is not provided, a large bubble 43 is generated in the lower part (bottom part) of the case 7.

  The generation of such large bubbles 43 is particularly noticeable in a mounting structure including the base 17 provided with the metal layers 13 and 15 on both surfaces of the ceramic substrate 11. In this case, since it is necessary to form the metal layers 13 and 15 while holding the ceramic substrate 11 when the pedestal 17 is manufactured, the holding portion 11a in which the periphery of the ceramic substrate 11 protrudes from the metal layers 13 and 15 is required. It has. For this reason, the holding part 11a becomes a ridge and bubbles 43 are easily generated in the lower part thereof.

  On the other hand, in the present embodiment, the peripheral wall 5 and the partition wall 31 are provided with a vent hole 39 and a communication portion 39 b that communicates with the lower portion of the vent hole 39. Therefore, even when air is trapped in the lower part by the filled epoxy resin 41 in the process of filling the epoxy resin 41, the air passes through the communication part 39 b and the vent hole 39 to the outside from the opening 39 a at the upper part of the vent hole 39. To be released. For this reason, as shown in FIG. 8, even in the mounting structure including the holding portion 11 a described above on the ceramic substrate 11, the epoxy resin 41 can be more reliably guided to the bottom portion of the case 7, and the generated bubbles 43 are generated. , Can be kept smaller.

  At that time, since the lower part of the vent hole 39 communicates with the bottom part of the case 7 through the communication part 39 b, the air pushed into the bottom part (bottom face) of the case 7 can be more reliably transmitted through the communication part 39 b and the vent hole 39. Can be released to the outside. By making the bubbles 43 smaller, the filled epoxy resin 41 is less likely to be peeled off, and a highly reliable product such as moisture-proofing, insulating effect, and improvement in solder life can be obtained by potting and sealing.

  Further, in the present embodiment, a communication portion 39b that communicates with the lower portions of the plurality of vent holes 39 is provided in the lower portion of the peripheral wall 5 and the partition wall portion 31, and the opening 39b1 of the communication portion 39b opens at the bottom of the case 7. Thus, it is continuously formed over the entire circumference of the peripheral wall 5 and the partition wall 31 which are side walls. For this reason, the air pushed into the bottom of the case 7 can be discharged to the outside over a wide range of the entire circumference in the region 9 surrounded by the peripheral wall 5 (long side portion 27, short side portion 29) and the partition wall portion 31. The generation of bubbles 43 can be further reduced.

  In the present embodiment, the communication portion 39b includes a communication passage 39b2 that directly communicates with the lower portions of the plurality of vent holes 39, and an opening 39b1 that is located below the communication passage 39b2 and opens at the bottom in the case 7. And have. In this case, part of the air taken into the opening 39b1 from the bottom in the case 7 flows directly from the vicinity of the position corresponding to the vent 39 to the vent 39, and the other part is shown in FIGS. Once taken into the communication path 39b2.

  The air once taken into the communication path 39b2 flows in the circumferential direction through the communication path 39b2, reaches the vent hole 39, and is discharged to the outside from the opening 39a at the upper part of the vent hole 39. In this case, the air taken into the communication path 39b2 located above the opening 39b1 from the opening 39b1 is prevented from flowing back from the communication path 39b2 to the opening 39b1 by the projection 39c shown in FIGS. Thus, the air can be efficiently guided to the vent hole 39.

  In the present embodiment, the lower surface of the upper wall in the communication passage 39b2 is the center between the adjacent vent holes 39 along the circumferential direction of the peripheral wall 5 and the partition wall 31 as shown in FIG. 7B. It can also be set as the structure provided with the inclined surface 39b3 inclined so that the ventilation hole 39 side may become the upper side with respect to the position S. In this case, the air taken into the communication path 39b2 from the opening 39b1 flows more efficiently and smoothly along the inclined surface 39b3 to the vent hole 39, the air discharge efficiency is further improved, and the generation of bubbles 43 is further reduced. can do.

  Further, in the present embodiment, when the air in the region 9 inside the case 7 is allowed to escape to the outside through the vent hole 39, the air can be sucked from the outside of the vent hole 39. Thus, even if the resin injected into the region 9 is so viscous that it is difficult to reach the bottom of the case 7 due to its own weight, for example, the resin is forced to be sucked from the vent hole 39 to remove the resin from the case 9. 7, the generation of the bubbles 43 can be suppressed.

  As mentioned above, although embodiment of this invention was described, these embodiment is only the illustration described in order to make an understanding of this invention easy, and this invention is not limited to the said embodiment. The technical scope of the present invention is not limited to the specific technical matters disclosed in the above embodiment, but includes various modifications, changes, alternative techniques, and the like that can be easily derived therefrom.

  For example, in the above-described embodiment, the resin used for potting is the epoxy resin 41, but is not limited thereto. Further, the present invention can also be applied to a mounting structure that does not include the holding portion 11 a in which the peripheral edge of the ceramic substrate 11 is protruded from the metal layers 13 and 15.

1 Power semiconductor module (semiconductor module)
5 Case peripheral wall (case side wall)
7 Case 9 Region inside the side wall of the case 23 Power semiconductor element 31 Partition (side wall of the case)
39 Ventilation hole 39b Communication portion 39b1 Opening portion of communication portion 39b2 Communication passage of communication portion 39b3 Inclined surface of communication passage (lower surface of upper wall)
41 Epoxy resin (resin)

Claims (6)

  A semiconductor module (1) having a structure in which a semiconductor element (23) disposed in a case (7) is potted and sealed with a resin (41), and the side walls (5, 31) of the case (7) A semiconductor module comprising a vent hole (39) extending in the vertical direction, and a lower portion of the vent hole (39) communicating with a bottom portion in the case (7).   A plurality of the vent holes (39) are provided on the side walls (5, 31) of the case (7), and a communication portion (39b) that communicates the lower portions of the plurality of vent holes (39) is provided on the case (7). Provided in the lower part of the side wall (5, 31), the communication part (39b) is continuously formed over the entire circumference of the side wall (5, 31) by opening at the bottom of the case (7). The semiconductor module according to claim 1.   The communication part (39b) is located below the communication path (39b2) and communicates with the lower part of the plurality of vent holes (39), and is open at the bottom of the case (7). The semiconductor module according to claim 2, further comprising: an opening portion (39 b 1) to be formed.   The lower surface (39b3) of the upper wall in the communication passage (39b2) is located at a position (S) between the vent holes (39) adjacent to each other along the circumferential direction of the side wall (5, 31). The semiconductor module according to claim 3, wherein the semiconductor module is inclined so that the air hole (39) side is upward.   A method of manufacturing a semiconductor module (1) in which a semiconductor element (23) disposed in a case (7) is potted with a resin (41) and sealed, and the side walls (5, 31) of the case (7) are sealed. When the resin (41) is injected into the region (9) in which the semiconductor element (23) is disposed on the inner side, the air hole (39) provided in the side wall (5, 31) of the case (7) is passed through. A method of manufacturing a semiconductor module, characterized in that air in a region (9) inside a side wall (5, 31) of the case (7) is released to the outside.   6. The method of manufacturing a semiconductor module according to claim 5, wherein air is sucked from the outside of the vent hole (39) provided in the side wall (5, 31) of the case (7).

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