JP2005033140A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent a cooling liquid for cooling heat generated from a semiconductor element from flowing into the face side supporting a circuit board of a heat-dissipating substrate. <P>SOLUTION: A liquid escape groove 8 is provided in the outer periphery side from the cooling recess 7 of a cooling case 6. Moreover, there are provided a first sealing part 11 in the inner periphery side of the liquid escape groove 8, and a second sealing part 12 in the outer periphery side of the liquid escape groove 8, respectively, between the cooling case 6 and the heat-dissipating substrate 2. With the location that is located on the more outer periphery side than the second sealing part 12 and separate from the second sealing part 12 as a fastening location, the cooling case 6 is installed on the backside of the heat-dissipating substrate 2 by using a fastening member such as a fixing bolt 15 at this fastening location. By having such a structure, the flow of the cooling liquid into the circuit-supporting face side of the heat-dissipating substrate 2, especially, the flow of the cooling liquid through a bolt hole 16 is securely prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor device including a cooling mechanism that cools heat from a semiconductor element by bringing a coolant into contact with a heat dissipation board that supports a circuit board on which the semiconductor element is mounted, and particularly relates to improvement of the cooling mechanism. is there.

  Conventionally, a technique for preventing leakage of a coolant for cooling a semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) is known (for example, refer to Patent Document 1).

In the technique described in Patent Document 1, a first seal portion and a second seal portion using an O-ring are interposed between a cooling case in which a coolant flows and a heat dissipation substrate on which a semiconductor element is mounted. Thus, liquid tightness is ensured by press-contacting the cooling case and the heat dissipation board. Here, the first seal portion is provided on the outer peripheral side with respect to the concave portion through which the coolant in the cooling case flows, and the second seal portion is provided on the outer peripheral side further than the first seal portion. And the liquid escape groove | channel is provided in the predetermined location of the cooling case located between the 1st seal part and the 2nd seal part.
JP 2001-308246 A

  In the technique described in Patent Document 1 described above, a fixing bolt is inserted so as to pass through the sealing material serving as the second seal portion, with the second seal portion positioned on the outer peripheral side of the liquid escape groove as a fastening portion. Since the heat radiating board and the cooling case are fastened, there is a concern that the strength of the sealing material is reduced and the sealing material is damaged. And when the sealing material used as a 2nd seal part is damaged, a part of cooling fluid which leaked from the recessed part of the cooling case penetrate | invaded into a bolt hole, and the surface side of a thermal radiation board | substrate, ie, a semiconductor, passes through a bolt hole. There is a possibility that the desired performance as a semiconductor element cannot be obtained by flowing into the element side.

  The present invention was devised to solve the above-described problems of the prior art, and it is ensured that a coolant for cooling the heat generated from the semiconductor element flows into the surface side of the heat dissipation substrate. An object of the present invention is to provide a semiconductor device having a structure capable of preventing the above.

  A semiconductor device according to the present invention includes a heat dissipation board that supports a circuit board on which a semiconductor element is mounted, and a cooling case attached to the back side of the heat dissipation board, and a cooling recess provided in the cooling case. The cooling liquid is allowed to flow into the heat dissipation substrate at a position facing the cooling recess, and the heat transferred from the semiconductor element to the heat dissipation substrate is absorbed by the cooling liquid. A liquid escape groove is provided on the outer peripheral side of the cooling recess to allow the coolant leaking from the cooling recess to escape to the outside of the cooling case, and between the cooling case and the heat radiating board, a liquid escape groove is provided on the inner peripheral side of the liquid escape groove. 1 seal part and a second seal part are provided on the outer peripheral side of the liquid escape groove, respectively, and a fastening member is provided at the fastening position at a position spaced from the second seal part on the outer peripheral side of the second seal part. Use cooling case It is obtained to attach on the back side of the heat substrate.

  In this semiconductor device, since the liquid escape groove is provided between the first seal portion and the second seal portion on the outer peripheral side of the cooling recess of the cooling case, it is temporarily impossible to secure the liquid tightness by the first seal portion. Even so, the coolant leaking out from the cooling recess is discharged from the liquid escape groove to the outside of the cooling case. Moreover, since the position which is the outer peripheral side of the second seal part and is separated from the second seal part is used as a fastening position, the cooling case is attached to the back surface side of the heat dissipation board using the fastening member at this fastening position. The fastening member does not cause a decrease in the strength of the sealing material that becomes the second seal portion, and the liquid tightness by the second seal portion is ensured, so that the coolant flows into the fastening position, and thus the fastening position. Therefore, the problem that the coolant flows into the surface side of the heat dissipation board that supports the circuit board is also effectively avoided.

  According to the semiconductor device of the present invention, even when the coolant for cooling the heat from the semiconductor element leaks out from the cooling recess of the cooling case, the leaked coolant is removed from the liquid escape groove. It can be surely discharged to the outside of the cooling case, and in particular, this leaked coolant can be reliably prevented from flowing into the fastening area between the heat dissipation board and the cooling case, and the circuit board of the heat dissipation board from this fastening position. It is possible to effectively avoid the problem that the coolant flows into the surface side supporting the.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, although the example which applied this invention with respect to the power module used for the drive control of a three-phase motor here is demonstrated concretely, this invention is not limited to the example given here, The semiconductor element which heat | fever-generates at the time of operation | movement It can be widely applied to any semiconductor device having

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view schematically showing the power module 1 of the first embodiment to which the present invention is applied, FIG. 2 is an enlarged cross-sectional view showing a portion A in FIG. 1, and FIG. FIG. 4 is a cross-sectional view schematically showing the positional relationship of each member when the heat dissipation board 2 is cut along the line X1-X2 in FIG.

  A power module 1 to which the present invention is applied includes a heat radiating substrate 2 made of a material having high thermal conductivity, such as aluminum, formed into a plate shape. A circuit board 3 is mounted on the heat dissipation board 2 via an insulating layer, and a semiconductor element 4 such as an IGBT is mounted on the circuit board 3. That is, the circuit board 3 on which the semiconductor element 4 is mounted is supported on the heat dissipation board 2. Hereinafter, for convenience, the surface of the heat dissipation substrate 2 that supports the circuit board 3 is referred to as a circuit support surface or surface, and the opposite surface is referred to as the back surface of the heat dissipation substrate 2.

  On the back surface side of the heat dissipation board 2, a plurality of heat dissipation fins 5 are erected in a portion located immediately below the circuit board 3. These heat radiating fins 5 are for increasing the surface area on the back surface side of the heat radiating board 2 to increase the cooling efficiency of the heat radiating board 2, and are formed integrally with the heat radiating board 2. And the cooling case 6 is attached to the back surface side of the thermal radiation board | substrate 2 with which this thermal radiation fin 5 was provided.

  The cooling case 6 is formed by forming a coolant flow path for circulating a coolant on a single substrate material by precision fine processing such as etching. A part of the coolant flow path formed in the cooling case 6 is a cooling recess 7 that opens on the heat dissipation substrate 2 side. When the cooling case 6 is attached to the back surface side of the heat radiating substrate 2, a plurality of heat radiating fins 5 formed on the back surface side of the heat radiating substrate 2 are accommodated in the cooling recess 7, and in this state, for cooling The opening of the recess 7 is closed on the back side of the heat dissipation substrate 2.

  Further, the cooling case 6 is located on the outer peripheral side of the cooling recess 7, and when the coolant leaks from the cooling recess 7 for some reason, the leaked coolant is transferred to the outside of the cooling case 6. A liquid escape groove 8 for discharging is provided. The liquid escape groove 8 is provided in the cooling case 6 so as to surround the cooling recess 7, and a part thereof penetrates in the thickness direction of the cooling case 6. The coolant leaking from the cooling recess 7 is transferred from the portion of the liquid escape groove 8 penetrating the cooling case 6 to the back surface of the cooling case 6 (surface opposite to the mounting surface to the heat dissipation board 2). It flows and is discharged to the outside of the cooling case 6. Corresponding to the liquid escape groove 8 provided in the cooling case 6, a recess 9 continuous with the liquid escape groove 8 is provided on the back surface side of the heat dissipation substrate 2.

  Between the attachment surface of the cooling case 6 to the heat radiating board 2 and the back surface side of the heat radiating board 2, the first and the second for ensuring the liquid-tightness of the cooling liquid so as to surround the cooling recess 7 of the cooling case 6. Second seal portions 11 and 12 are provided, respectively. As these 1st and 2nd sealing parts 11 and 12, sealing materials, such as an O-ring, are used, for example, These sealing materials are respectively in the sealing material accommodation recessed parts 13 and 14 provided in the back surface side of the thermal radiation board 2. It is accommodated and the attachment surface to the heat sink 2 of the cooling case 6 and the back surface side of the heat sink 2 are stuck.

  Here, the first seal portion 11 is disposed on the outer peripheral side of the cooling recess 7 of the cooling case 6 and on the inner peripheral side of the liquid escape groove 8. On the other hand, the second seal portion 12 is disposed at a position on the outer peripheral side of the liquid escape groove 8. In the power module 1, the circuit support of the heat dissipation board 2 is supported by attaching the cooling case 6 to the back side of the heat dissipation board 2 with the first and second seal portions 11 and 12 interposed therebetween. It is possible to reliably prevent the coolant from flowing into the surface side.

  That is, in the power module 1, since the outer peripheral side of the cooling recess 7 provided in the cooling case 6 is surrounded by the first seal portion 11, as long as the liquid tightness by the first seal portion 11 is ensured. Does not leak from the cooling recess 7. Even if the liquid tightness due to the first seal portion 11 cannot be ensured for some reason and the coolant leaks from the cooling recess 7, the liquid escape groove 8 is formed on the outer peripheral side of the first seal portion 11. Since the second seal portion 12 is provided on the outer peripheral side, the coolant leaking from the cooling recess 7 is guided to the liquid escape groove 8 from which the outside of the cooling case 4 is provided. Will be discharged. Therefore, the coolant is effectively prevented from flowing into the circuit support surface side of the heat dissipation board 2.

  In particular, in the power module 1 to which the present invention is applied, a fixing bolt 15 or the like at the fastening position is set at a fastening position at a position further on the outer peripheral side of the second seal part 12 and separated from the second seal part 12. The cooling case 6 is attached to the rear surface side of the heat dissipation board 2 using the fastening member. That is, a bolt hole 16 that penetrates the heat dissipation substrate 2 and reaches the cooling case 6 is drilled at an appropriate position on the outer peripheral side of the second seal portion 12 and away from the second seal portion 12. When the fixing bolt 15 is inserted into the cooling plate 16, the cooling case 6 is attached to the back side of the heat dissipation substrate 2.

  As described above, when the bolt hole 16 is formed so as to penetrate the heat radiating board 2, the coolant leaked from the cooling recess 7 of the cooling case 6 passes through the bolt hole 16 to the circuit support surface side of the heat radiating board 2. It is necessary to surely prevent it from flowing into. In the power module 1 to which the present invention is applied, the bolt hole 16 is drilled at a position that is further on the outer peripheral side of the second seal portion 12 and spaced from the second seal portion 12. The coolant leaking from the cooling recess 7 of the case 6 is reliably blocked by the second seal portion 12 and does not reach the bolt hole 16 drilled on the outer peripheral side thereof. Therefore, the coolant is reliably prevented from flowing into the circuit support surface side of the heat dissipation board 2 through the bolt holes 16. Further, since the fixing bolt 15 is inserted at a position away from the second seal portion 12, the fixing bolt 15 interferes with the second seal portion 12, and causes damage to the second seal portion 12. The liquid-tightness by the 2nd seal | sticker part 12 is maintained favorably.

  By the way, when the position closer to the outer peripheral side of the second seal portion 12 and away from the second seal portion 12 is set as the fastening position, in the vicinity of the second seal portion 12, the fastening plate 15 is tightened with the heat dissipation substrate 2 by the tightening force. Since a high surface pressure is obtained between the cooling case 6 and the second seal portion 12, sufficient liquid-tightness can be provided, but the surface pressure in the vicinity of the first seal portion 11 that is far away from the fastening position. It is also conceivable that the liquid tightness due to the first seal part 11 is reduced due to shortage of the liquid. In such a case, a bolt hole 17 is drilled from the cooling case 6 side at a position in the vicinity of the first seal portion 11 and a bolt 18 is inserted. The surface pressure should be ensured. At this time, if the bolt holes 17 through which the bolts 18 are inserted do not penetrate the heat dissipation board 2, the coolant leaked from the cooling recesses 7 of the cooling case 6 passes through the bolt holes 17 and the circuit of the heat dissipation board 2. It does not flow into the support surface.

  In the power module 1 configured as described above, heat generated from the semiconductor element 4 such as an IGBT during operation is transmitted to the heat dissipation substrate 2. At this time, the coolant flows in the cooling recess 7 of the cooling case 6, and the radiating fins 5 formed on the back surface side of the heat radiating substrate 2 and the peripheral portions thereof contact the coolant flowing in the cooling recess 7. As a result, the heat transferred from the semiconductor element 4 to the heat dissipation substrate 2 is absorbed by the coolant and cooled.

  Since the coolant flowing in the cooling recess 7 of the cooling case 6 is normally blocked by the first seal portion 11, it does not leak from the cooling recess 7. Even if the liquid tightness due to the first seal portion 11 cannot be ensured due to some factor and the coolant leaks from the cooling recess 7, the liquid escape groove 8 is formed on the outer peripheral side of the first seal portion 11. Since the second seal portion 12 is provided on the outer peripheral side, the coolant leaking from the cooling recess 7 is discharged from the liquid escape groove 8 to the outside of the cooling case 4, and It is prevented from flowing into the circuit support surface side. Furthermore, in the power module 1 to which the present invention is applied, the bolt hole 16 for attaching the cooling case 4 to the heat radiating substrate 2 is located on the outer peripheral side of the second seal portion 12 and separated from the second seal portion 12 (fastening). The coolant leaking out from the cooling recess 7 does not reach the bolt hole 16 and the coolant flows into the circuit support surface side of the heat dissipation board 2 through the bolt hole 16. Is also reliably prevented.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view showing a main part of the power module 20 of the second embodiment.

  The power module 20 of the second embodiment has the same basic configuration as that of the power module 1 of the first embodiment described above, and a sealing material housing recess 14 for housing the sealing material of the second seal portion 12 includes: It is characterized in that it is formed on the back side of the heat radiating substrate 2 as a concave portion integral with the concave portion 9 continuous with the liquid escape groove 8. Hereinafter, only this characteristic part will be described.

  Also in the power module 20 of the present embodiment, the first seal portion 11, the liquid escape groove 8, and the second seal portion 12 are arranged in this order from the cooling recess 7 provided in the cooling case 6 toward the outer peripheral side. Further, a position on the further outer peripheral side of the second seal portion 12 and separated from the second seal portion 12 is a fastening position between the heat dissipation substrate 2 and the cooling case 6. However, in the power module 20 of this embodiment, the position of the second seal portion 12 is closer to the liquid escape groove 8 than that of the first embodiment, and the sealing material accommodation recess 14 is continuous with the liquid escape groove 8. It is formed on the back side of the heat dissipation substrate 2 as a concave portion integrated with the concave portion 9 to be performed. And it has the structure where the sealing material used as the 2nd seal part 12 is accommodated in this sealing material accommodation recessed part 14. As shown in FIG.

  In the power module 20 of the present embodiment, the sealing material accommodating recess 14 and the recess 9 are integrated, whereby the following effects are obtained in addition to the effects of the first embodiment described above. That is, since the sealing material accommodation recess 14 and the recess 9 are configured as an integral recess, the processing on the back surface side of the heat dissipation substrate 2 is simplified, and the sealing material of the second seal portion 12 is used as the sealing material accommodation recess 14. The work of fitting in can be easily performed. Therefore, it is possible to reduce the manufacturing cost.

  Further, since it is not necessary to provide a wall separating the sealing material accommodating recess 14 and the recess 9 from each other, the size of the power module 20 as a whole can be reduced accordingly.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a plan view showing the back side of the heat dissipation board 2 provided in the power module of the third embodiment.

  Also in the power module of the present embodiment, the sealing material accommodation concave portion 14 for accommodating the sealing material of the second seal portion 12 is a concave portion that is continuous with the liquid escape groove 8, similarly to the power module 20 of the second embodiment. 9 is formed on the back side of the heat dissipation substrate 2 as a concave portion integrated with the heat sink 9. In particular, the power module according to the present embodiment has a structure in which the concave portion 9 continuous with the liquid escape groove 8 is divided into a plurality of regions by the partition walls 31 discretely provided in the concave portion 9.

  When the concave portion 9 that is continuous with the sealing material accommodating concave portion 14 and the liquid escape groove 8 is formed as an integral concave portion, a wide concave portion is formed in the heat radiating substrate 2, so that the heat radiating substrate 2 is likely to be twisted or distorted. Become. Such a twist or distortion generated in the heat dissipation board 2 is not so much a problem when the size of the heat dissipation board 2 is small, but there is a concern that when the size of the heat dissipation board 2 is increased, liquid tightness may be lowered. Is done.

  Therefore, in the power module of the present embodiment, a plurality of partition walls 31 are provided discretely in the recesses 9 that are continuous with the liquid escape grooves 8, and the recesses 9 are divided into a plurality of regions by the plurality of partition walls 31. Yes. Thereby, the rigidity of the heat radiating board 2 is improved and the occurrence of twisting and distortion is suppressed, and even when the size of the heat radiating board 2 is large, it is possible to ensure good liquid tightness. Of course, in the power module of this embodiment, the same effects as those of the first embodiment and the second embodiment described above can be obtained.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view showing a main part of the power module 40 of the fourth embodiment.

  Also in the power module 40 of the present embodiment, the sealing material accommodating recess 14 for accommodating the sealing material of the second seal portion 12 is continuous with the liquid escape groove 8, as in the power module 20 of the second embodiment. The concave portion 9 and the concave portion 9 are formed on the back surface side of the heat dissipation substrate 2. In particular, in the power module 40 of the present embodiment, the depth D1 of the recess 9 that is continuous with the liquid escape groove 8 is smaller than the depth D2 of the seal material accommodation recess 14.

  In the power module 40 of the present embodiment, as described above, the depth D1 of the recess 9 that is continuous with the liquid escape groove 8 is made smaller than the depth D2 of the seal material receiving recess 14, so that the rigidity of the heat dissipation substrate 2 is increased. Improvements are being made. Therefore, also in this power module 40, since the generation | occurrence | production of the twist and distortion of the thermal radiation board | substrate 2 is suppressed effectively, even when the size of the thermal radiation board | substrate 2 is large, it is possible to ensure favorable liquid-tightness. It becomes. Of course, in the power module 40 of the present embodiment, the same effects as those of the first and second embodiments described above can be obtained.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a cross-sectional view schematically showing the power module 50 of the fifth embodiment, and FIG. 9 is an enlarged cross-sectional view showing a portion B in FIG.

  In the power module 50 of the fifth embodiment, the cooling case 6 is arranged with the first member 6a provided with the cooling recess 7 and a predetermined gap on the outer peripheral side of the first member 6a. The second member 6b is provided, and the gap between the first member 6a and the second member 6b is a liquid escape groove 8.

  Also in the power module 50 of the present embodiment, the first seal portion 11, the liquid escape groove 8, and the second seal portion 12 extend from the cooling recess 7 provided in the first member 6 a of the cooling case 6 toward the outer peripheral side. Are arranged in this order, and a position on the further outer peripheral side of the second seal portion 12 and away from the second seal portion 12 is a fastening position between the heat dissipation board 2 and the cooling case 6. However, in the power module 50 of the present embodiment, the gap between the first member 6a and the second member 6b constituting the cooling case 6 is the liquid escape groove 8. That is, in the power module 50 of the present embodiment, the cooling case 6 is not grooved to form the liquid escape groove 8 actively, but the first member 6a and the second member constituting the cooling case 6 are formed. By adjusting the positional relationship with 6b, a liquid escape groove 8 is formed between them. Further, the concave portion 9 continuing to the liquid escape groove 8 is not formed on the back surface side of the heat dissipation substrate 2.

  Also in the power module 50 having the above structure, the first seal portion 11, the liquid escape groove 8, and the second seal portion 12 are arranged in this order on the outer peripheral side of the cooling recess 7, respectively. Furthermore, since the position on the outer peripheral side and separated from the second seal portion 12 is the fastening position between the heat dissipation substrate 2 and the cooling case 6, the same effect as in the first embodiment described above can be obtained. In addition, by arranging the position of the second seal portion 12 at a position adjacent to the liquid escape groove 8, the size of the entire power module 50 can be reduced.

It is sectional drawing which shows typically the power module of 1st Embodiment to which this invention is applied. It is sectional drawing which expands and shows the A section in FIG. It is a top view which shows the back surface side of the heat sink with which the power module of 1st Embodiment is provided. It is sectional drawing which shows typically the positional relationship of each member when the said thermal radiation board | substrate is cut | disconnected along the X1-X2 line | wire in FIG. It is sectional drawing which expands and shows the principal part of the power module of 2nd Embodiment to which this invention is applied. It is a top view which shows the back surface side of the heat sink with which the power module of 3rd Embodiment to which this invention is applied is provided. It is sectional drawing which expands and shows the principal part of the power module of 4th Embodiment to which this invention is applied. It is sectional drawing which shows typically the power module of 5th Embodiment to which this invention is applied. It is sectional drawing which expands and shows the B section in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20,40,50 Power module 2 Heat sink 3 Circuit board 4 Semiconductor element 6 Cooling case 7 Cooling recessed part 8 Liquid escape groove 9 Recessed part 11 1st seal part 12 2nd seal part 13, 14 Sealing material accommodation recessed part

Claims (5)

It has a heat dissipation board that supports the circuit board on which the semiconductor element is mounted, and a cooling case attached to the back side of the heat dissipation board, and a coolant is allowed to flow in the cooling recess provided in the cooling case, In the semiconductor device in which the coolant is brought into contact with the heat dissipation substrate at a position facing the cooling recess, and the heat transferred from the semiconductor element to the heat dissipation substrate is absorbed by the coolant.
Provided on the outer peripheral side of the cooling recess of the cooling case with a liquid escape groove for escaping the coolant leaking from the cooling recess to the outside of the cooling case,
Between the cooling case and the heat dissipation substrate, a first seal portion is provided on the inner peripheral side of the liquid escape groove, and a second seal portion is provided on the outer peripheral side of the liquid escape groove, respectively.
A position at the outer peripheral side of the second seal part and separated from the second seal part is a fastening position, and the cooling case is attached to the back side of the heat dissipation board using a fastening member at the fastening position. A featured semiconductor device.   On the back side of the heat radiating substrate, there are provided a recess that is continuous with the liquid escape groove provided in the cooling case, and a recess that accommodates a sealing material that serves as the second seal portion, and these recesses are formed integrally. The semiconductor device according to claim 1, wherein:   3. The semiconductor device according to claim 2, wherein the recess that is continuous with the liquid escape groove provided on the back side of the heat dissipation substrate is divided into a plurality of recesses by a plurality of discrete partitions. .   The depth of the concave portion that is continuous with the liquid escape groove provided on the back surface side of the heat dissipation substrate is smaller than the depth of the concave portion in which the sealing material that serves as the second seal portion is accommodated. The semiconductor device according to claim 2.   The cooling case includes a first member provided with the cooling recess and a second member disposed with a predetermined gap on the outer peripheral side of the first member. The semiconductor device according to claim 1, wherein a gap between the first member and the second member serves as the liquid escape groove.

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