JP2007201225A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct liquid-cooling semiconductor device capable of sealing reliably so that no liquid is leaked from the sealed section of a semiconductor module with a relatively simple configuration. <P>SOLUTION: The semiconductor device has a semiconductor module 1 and a liquid-cooled member 2. A circulation path 21 of a cooling liquid, and an opening 22 where the circulation path 21 is exposed partially are formed in the liquid-cooled member 2. A surrounding wall 25 is formed opposite to the peripheral side of the semiconductor module 1. The semiconductor module 1 and the liquid-cooled member 2 are joined integrally and the cooling surface of the semiconductor module 1 faces the opening 22. A first sealing member 3a is fitted to the position of the periphery for surrounding the opening 2 of the liquid-cooled member 2 between the opposing surfaces of both of them 1, 2. A second sealing member 3b is inserted between the opposing surfaces of the peripheral side of the semiconductor module 1 and the surrounding wall 25 of the liquid-cooled member 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device having a function of cooling a semiconductor module including a semiconductor element having a large calorific value, and more particularly, to a semiconductor device having a direct liquid cooling structure for directly cooling a semiconductor module with a cooling liquid. .

  In a semiconductor device that handles a large amount of power such as an inverter that drives a motor of an electric vehicle or a hybrid vehicle, a semiconductor module in which a plurality of power semiconductor elements such as an insulated gate bipolar transistor (IGBT) that consumes a large amount of power is packaged. It is used. Such a power semiconductor module has a large amount of heat generation, and thus needs to be efficiently cooled. In particular, since the power density of recent semiconductor modules for electric power has been improved, so-called direct liquid cooling, in which the semiconductor module is directly cooled with a cooling liquid to improve the cooling performance, is being increasingly adopted. In this case, since the installation space is small in the automobile, it is required to be as small as possible.

  By the way, in the conventional direct liquid cooling type, the cooling surface of the semiconductor module faces the opening of the flow path formed in the liquid cooling member, and the gap between the opening periphery of the liquid cooling member and the periphery of the semiconductor module. By integrally joining the semiconductor module and the liquid cooling member with the sealing member interposed therebetween, the cooling liquid directly cools the cooling surface of the semiconductor module, and the cooling liquid is discharged from the flow path to the outside by the sealing member. It has a structure that prevents leakage (see, for example, Patent Document 1). In this case, what is generally called a gasket or an O-ring is applied as the seal member.

  However, with such a structure, liquid leakage may occur due to non-uniform pressure applied to the seal member, biting of foreign matter due to foreign matter adhering to the seal surface, or damage or aging of the seal member. There is. And if the coolant leaks from this seal part and wets the electrode terminals of the semiconductor module, the electrical insulation may deteriorate due to an electrical short circuit between the electrodes, and the semiconductor module may break down. There is a problem that the period that can be guaranteed cannot be extended.

  Therefore, in the prior art, measures are taken such as preventing the leakage by arranging the sealing member in an inner and outer double around the opening of the liquid cooling member so that the cooling liquid does not leak from the sealing portion.

  However, even when such measures are taken, it is difficult to properly adjust the tightening pressures of the inner and outer double seal members independently of each other. There was a risk of causing liquid leakage through the seal member.

  Therefore, in the prior art, a leakage discharge groove for discharging the leakage and a drain hole communicating with the leakage discharge groove are formed in a portion located outside the sealing member of the cooling member, and the coolant is discharged from the sealing portion. In the case of leakage, a structure has been proposed in which this cooling liquid is guided to the outside of the apparatus via a liquid discharge groove and a liquid drain hole to prevent a short circuit between electrode terminals (for example, a patent) Reference 2-4 etc.).

JP-A-9-246443 JP 2001-308246 A JP 2003-31745 A JP 2005-32904 A

  However, in the case of the conventional structures described in Patent Documents 2 to 4, the configuration is complicated because an extra cutting process such as forming a liquid discharge groove or a liquid drain hole is required in the liquid cooling member. And costly. Moreover, if the actual use environment is not good, there is a problem that the liquid leakage drain groove or liquid drain hole is clogged with dust and the liquid leakage cannot be discharged to the outside.

  The present invention solves the above-described problems and provides a semiconductor device that can be reliably sealed with a relatively simple structure so that liquid leakage does not occur from the sealed portion between the semiconductor module and the liquid cooling member. The issue is to provide.

  In order to solve the above-described problems, the present invention has a semiconductor module on which a semiconductor element is mounted, a coolant flow passage inside, and an opening formed so that a part of the flow passage is exposed to the outside. A liquid cooling member, the semiconductor module and the liquid cooling member are integrally joined via two sealing members to close the opening, and the cooling surface of the semiconductor module is the flow channel A direct liquid cooling type semiconductor device facing the road employs the following configuration.

  That is, in the first invention, a peripheral wall portion is formed on the liquid cooling member so as to face the peripheral side surface substantially orthogonal to the cooling surface of the semiconductor module, and one of the two sealing members is the liquid sealing member. It is attached to the peripheral part surrounding the opening of the cooling member and is pressed by tightening the semiconductor module and the liquid cooling member, and the other sealing member is the peripheral side surface of the semiconductor module and the peripheral wall part formed on the liquid cooling member It is characterized by being inserted between opposing surfaces.

  In the second invention, the two sealing members are both interposed between opposing surfaces of the cooling surface side of the semiconductor module and the opening forming side of the liquid cooling member, and the semiconductor module and the liquid It is characterized in that the pressure applied to each seal member is made different by making the distance between the opposing surfaces of the cold member different from each other at the position of each seal member. In this case, the thicknesses of the two seal members can be made different from each other instead of making the distance between the opposing surfaces of the semiconductor module and the liquid cooling member different at the position of each seal member.

  According to the first aspect of the present invention, the liquid leakage is double sealed by the two sealing members, and the tightening surfaces of the two sealing members are two different surfaces orthogonal to each other. The possibility of causing foreign matter to leak and cause liquid leakage is extremely reduced. Furthermore, since the sealing methods of the two seal members are different, the risk of insufficient seals occurring at both seal members is greatly reduced. In particular, the sealing member inserted between the opposing surfaces of the peripheral side surface of the semiconductor module and the peripheral wall portion formed on the liquid cooling member is more than the sealing member pressurized by tightening the conductor module and the liquid cooling member. Therefore, even if liquid leakage occurs in the sealing member located at the periphery of the opening, the opposing surface between the peripheral side surface of the semiconductor module and the peripheral wall formed on the liquid cooling member Liquid leakage can be prevented by the seal member inserted between them.

  According to the second invention, since the distance between the facing surfaces of the semiconductor module and the liquid cooling member is different from each other at the positions of the two sealing members, when the conductor module and the liquid cooling member are tightened, the pressure applied to both the sealing members is reduced. Can be different from each other. For this reason, the allowable range of the pressurizing force of each seal member is widened, and since the pressurizing force suitable for each seal method can be applied to each seal member, liquid leakage generated in each seal member is surely prevented. can do. The same applies to the case where the thicknesses of the two seal members are different from each other.

Embodiment 1 FIG.
1 is a longitudinal sectional view showing a main part of a semiconductor device according to Embodiment 1 of the present invention.

  The semiconductor device according to the first embodiment includes a semiconductor module 1 and a liquid cooling member 2. The semiconductor module 1 has a rectangular parallelepiped shape as a whole, and a plurality of power switching elements 11 such as IGBTs as semiconductor elements are soldered on the wiring pattern 13 formed on the surface of the insulating substrate 12. Further, each switching element 11 is wire-bonded to the wiring pattern 13 via a fine metal wire 14 such as an aluminum wire and electrically connected thereto.

  A module base 15 made of a material having high thermal conductivity such as copper or aluminum is fixed to the back surface of the insulating substrate 12. The module base 15 efficiently conducts heat generated from the switching element 11 to the outside, and at the same time plays a role for reliably sealing a first seal member 3a described later.

  Further, in order to protect the switching element 11 and the fine metal wires 14 from the external environment, a module case 16 that covers them is bonded and fixed to the peripheral portion of the module base 15. A protrusion 16a is formed on an upper portion of the peripheral side portion of the module case 16 so as to press a second seal member 3b, which will be described later, so that the module case 16 is easily positioned at a predetermined position. Although not shown, electrode terminals for connecting to an external electric circuit when the semiconductor module 1 is used are provided on the upper surface or side surface of the module case 16 and are electrically connected to the wiring pattern 13. .

  On the other hand, the liquid cooling member 2 is made of a metal such as copper or aluminum, or a resin such as PPS (polyphenylene sulfide), and a cooling liquid flow passage 21 is formed in the liquid cooling member 2. An opening 22 is provided so that the portion is exposed to the outside. A mounting groove 23 is formed in the peripheral portion of the opening 22, and a first seal member 3 a made of a rubber gasket or the like is mounted in the mounting groove 23.

  In addition, a peripheral wall 25 is integrally formed on the liquid cooling member 2 so as to face the peripheral side surface of the module case 16 substantially orthogonal to the cooling surface of the semiconductor module 1 (that is, the bottom surface of the module base 15). The second seal member 3 b is inserted between the opposing surfaces of the portion 25 and the peripheral side surface of the module case 16.

  When assembling the semiconductor device, the first seal member 3a is mounted in advance in the mounting groove 23 of the liquid cooling member 2, and the second seal member 3b is fitted into the peripheral side surface below the protrusion 16a of the module case 16. In this state, the semiconductor module 1 is pushed along the peripheral wall portion 25 of the liquid cooling member 2, whereby the second seal member 3 b is pushed and moved by the protruding portion 16 a to move with the peripheral wall portion 25 of the liquid cooling member 2. The module case 16 is inserted into a predetermined position between the opposed surfaces of the module case 16 and the peripheral side surface. And after pushing in the semiconductor module 1 along the surrounding wall part 25 of the liquid cooling member 2, the semiconductor module 11 and the liquid cooling member 2 are fastened with the volt | bolt etc. which are not shown in figure.

  Thus, the two sealing members 3a and 3b are double-sealed so that the coolant does not leak from the flow passage 21 to the outside. Further, since the bottom surface of the module base 15 serving as the cooling surface of the semiconductor module 11 faces the opening 22 of the liquid cooling member 2, the flow path 21 of the liquid cooling member 2 is made of an aqueous solution of a highly viscous liquid such as ethylene glycol. By flowing the coolant, the switching elements 11 constituting the semiconductor module 11 are cooled by the coolant via the module base 15.

  In the above-described configuration, the first seal member 3a is tightened between the semiconductor module 1 and the liquid cooling member 2 by the distance La between the opposing surfaces between the bottom surface of the module base 15 and the bottom surface of the mounting groove 23 of the liquid cooling member 2. It is compressed to a specified dimension and receives a predetermined pressure. Therefore, the pressure applied to the first seal member 3a is arbitrarily changed by adjusting the distance La between the opposing surfaces. The second seal member 3b is compressed to a dimension defined by a distance (gap dimension) Lb between opposing surfaces of the peripheral side surface of the module case 16 and the peripheral wall portion 25 of the liquid cooling member 2 and receives a predetermined pressure. . Therefore, the pressure applied to the second seal member 3b is arbitrarily changed by adjusting the distance Lb between the opposing surfaces. However, the second seal member 3b does not receive the pressing force for tightening the semiconductor module 1 and the cooling member.

  Here, the first seal member 3a is a method of sealing by tightening the semiconductor module 1 and the liquid cooling member 2 with a bolt or the like (hereinafter referred to as a tightening method), and the second seal member 3b is a member of the liquid cooling member 2. It is a system (hereinafter referred to as a “fitting system”) that is inserted between the opposed surfaces of the peripheral wall portion 25 and the peripheral side surface of the module case 16, and the sealing systems of both the sealing members 3 a and 3 b are different. In addition, the method of applying pressure to the seal members 3a and 3b is independent. Therefore, a pressure suitable for each sealing method can be applied to each of the seal members 3a and 3b, and the possibility that both the seal members 3a and 3b leak at the same time is extremely reduced.

  In particular, since the first seal member 3a is a tightening method, the pressure applied to the first seal member 3a may be uneven due to the difference in fastening force of each bolt, whereas the second seal member 3b. Since is a fitting method, the applied pressure acts equally on the second seal member 3b. For this reason, even if a liquid leak occurs in the first seal member 3a, the second seal member 3b can prevent the liquid leak. Further, since the tightening surfaces of the seal members 3a and 3b are two different surfaces that are orthogonal to each other, there is very little possibility that the seal members 3a and 3b simultaneously bite foreign matter and cause liquid leakage.

  Further, from the viewpoint of processing the liquid cooling member 2, the peripheral portion of the opening 22 facing the module base 15 is flattened while the peripheral wall portion 25 of the liquid cooling member 2 is laterally processed. The surface condition is not the same. For example, in processing using a milling machine, there is a possibility that a processing trace on a flat surface may be a processing trace extending along a direction orthogonal to the axial direction around which the first seal member 3a is circulated. 2 A processing mark extending along the axial direction in which the sealing member 3b is circulated is formed. Accordingly, liquid leakage may occur along the machining mark for the first seal member 3a, whereas leakage occurs because the machining mark is formed along the axial direction of the second seal member 3b. The possibility of liquid generation is extremely small. As a result, higher sealing performance can be obtained with the fitting-type second seal member 3b.

  As described above, in the first embodiment, in addition to the first sealing member 3a of the tightening method, the second sealing member 3b of the fitting method having a higher sealing property is provided to double seal the liquid leakage. Therefore, even when the apparatus is inclined or installed upright, the possibility that the first seal member 3a and the second seal member 3b may leak simultaneously becomes extremely small. Further, unlike the conventional structure, extra cutting work such as forming a liquid discharge groove and a liquid drain hole in the liquid cooling member 2 is unnecessary, so that the configuration is simplified and realized at a relatively low cost. Can do.

  In the first embodiment, a liquid leak sensor is installed at an intermediate position between the first seal member 3a and the second seal member 3b in the space sandwiched between the semiconductor module 1 and the liquid cooling member 2. The leakage sensor may detect the occurrence of liquid leakage from the first seal member 3a at an early stage before the liquid leakage from the second seal member 3b occurs.

  As a liquid leak sensor in this case, for example, two electrodes are arranged apart on the surface of the liquid cooling member 2 or the surface of the module base 15 and the insulation resistance between the two electrodes is measured to reduce the insulation resistance due to the liquid leak. Or a structure in which a water-absorbing insulating material is sandwiched between both electrodes to detect a capacity change due to moisture absorption of the interelectrode material, and the module base 15 and the liquid cooling member 2 are both formed of metal. If the seal members 3a and 3b are insulators such as rubber, various detection methods such as detecting the insulation resistance between the module base 15 and the liquid cooling member 2 can be employed.

Embodiment 2. FIG.
FIG. 2 is a longitudinal sectional view of a semiconductor device according to the second embodiment of the present invention. Components identical or corresponding to those of the first embodiment shown in FIG.

  The feature of the second embodiment is that two mounting grooves 23 and 24 having different depths are formed along the periphery of the opening 22 at the top of the liquid cooling member 2. In particular, here, the depth 24 of the mounting groove for the second seal member 3b is set somewhat shallower than the depth of the mounting groove 23 for the first seal member 3a. Further, the module base 15 of the semiconductor module 1 is set to have a size that protrudes outward from the module case 16 so as to be in contact with the seal members 3a and 3b.

  The first and second seal members 3a and 3b are mounted in the mounting grooves 23 and 24. In this state, the bottom surface of the module base 15 serving as the cooling surface of the semiconductor module 1 is the opening of the liquid cooling member 2. The semiconductor module 1 and the liquid cooling member 2 are aligned so as to face the portion 22, and both 1 and 2 are fastened together by a bolt or the like (not shown).

Therefore, in the second embodiment, the thicknesses of the two seal members 3a and 3b are the same, but the depths of the mounting grooves 23 and 24 in which the seal members 3a and 3b are mounted are different. The distances Lc and Ld between the opposing surfaces between the bottom surface of the module base 15 and the bottom surfaces of the mounting grooves 23 and 24 are different from each other at the position of the second seal member 3b. In this way, by adjusting the depth of the mounting grooves 23 and 24 for mounting the seal members 3a and 3b to each other, the distances Lc and Ld between the opposing surfaces are adjusted when the semiconductor module 1 and the liquid cooling member 2 are tightened. By doing so, the applied pressure to both seal members 3a and 3b can be changed independently.
Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted here.

Here, in general, the pressure applied to the seal member is defined by a crushing rate δh, which is a deformation amount obtained from the height of the original seal member before deformation and an interval deformed by compression. This crushing rate δh is expressed by the following equation.
δh = (Ho−Hg) / Ho × 100 [%]
Here, Ho is the height of the original seal member, and Hg is the distance between the opposing surfaces in the pressurized state of the seal member.

Further, the compression set δH gradually increases with time even when the crushing ratio δh is the same, and increases in a shorter time as the use temperature is higher. Usually, when the compression set reaches 80%, it is said that the service life of the seal member is reached. This compression set δH is given by the following equation.
δH = (Ho−Hp) / (Ho−Hg) × 100 [%]
Here, Hp is the height of the seal member after being left for a predetermined time in the compressed state.

  FIG. 3 is a characteristic diagram showing an example of the relationship between the crushing ratio δh and the compression set δH after the sealing member has been stored in air at 80 ° C. for 70 hours.

  As can be seen from FIG. 3, for example, when the depth of each mounting groove 23, 24 is set so that the crushing rate of the first seal member 3a is 20% and the crushing rate of the second seal member 3b is 25%, The compression set of the second seal member 3b is smaller than the compression set of the first seal member 3a. For this reason, the time until the second seal member 3b reaches the service life is longer than the time until the first seal member 3a reaches the service life.

  As described above, in the second embodiment, when the semiconductor module 1 and the liquid cooling member 2 are tightened by varying the depth of the mounting grooves 23 and 24 in which the seal members 3a and 3b are mounted, the distance between the opposing surfaces is reduced. By adjusting the distances Lc and Ld, the pressure applied to both the seal members 3a and 3b can be changed independently. Therefore, the allowable range of the pressure applied to both the seal members is expanded, and the pressure applied to the seal members 3a and 3b is increased. It is possible to prevent liquid leakage that occurs due to inappropriateness.

  In particular, the depth of the mounting groove 24 in which the second seal member 3b is mounted is set somewhat shallower than the depth of the mounting groove 23 in which the first seal member 3a is mounted. If the second seal member 3b located outside the permanent seal is adjusted so that the permanent strain generated is smaller than the permanent set, the service life of the second seal member 3b is extended. Even when a leak occurs, the second seal member 3b on the outer side has not yet deteriorated, and a liquid leak can be prevented.

  In the second embodiment, the depths of the mounting grooves 23 and 24 are varied in order to change the distances Lc and Ld between the opposing surfaces at the time of tightening. However, the present invention is not limited to this, and for example, the cooling surface of the module base 15 ( If processing on the bottom surface side is possible, a step is provided on the bottom surface of the module base 15 so that the distances Lc and Ld between the opposing surfaces of the first and second seal members 3a and 3b can be made different. It is.

  Further, as in the second embodiment, the depth of the mounting groove 24 of the second seal member 3b is set somewhat shallower than the depth of the mounting groove 23 of the first seal member 3a. On the contrary, the depth of the mounting groove 23 of the first seal member 3a is set somewhat shallower than the depth of the mounting groove 24 of the second seal member 3b. It is also possible to reduce the permanent distortion generated in one seal member 3a.

Embodiment 3 FIG.
FIG. 4 is a longitudinal sectional view of the semiconductor device according to the third embodiment of the present invention. Components identical or corresponding to those of the second embodiment shown in FIG.

  The feature of the third embodiment is that the thicknesses of the first and second seal members 3a and 3b are different. In particular, in Embodiment 3, the thickness of the second seal member 3b is set to be larger than the thickness of the first seal member 3a. Further, since the thicknesses of the seal members 3a and 3b are different, the depths of the mounting grooves 23 and 24 in which the seal members 3a and 3b are mounted are not the same, and the first and second seal members 3a and 3b are substantially the same. The depth is set so that the crushing ratio δh is the same. Therefore, the distance Lf between the opposing surfaces of the second seal member 3b is larger than the distance Le between the opposing surfaces of the first seal member 3a.

  FIG. 5 is a characteristic diagram showing an example of the relationship between the compression set and the thickness of the seal member after being stored at 100 ° C. for 70 hours with a crushing rate of 25% in the seal member.

  As can be seen from FIG. 5, there is a correlation between the compression set of the seal member and the thickness of the seal member. Even if the crushing ratio δh is the same, the compression set δH is increased when the thickness of the seal member is increased. Decreases rapidly. That is, the thicker the seal member, the smaller the deterioration with time and the longer the lifetime.

  Therefore, when the semiconductor module 1 and the liquid cooling member 2 are tightened, even if the crushing ratios δh of both the sealing members 3a and 3b are substantially the same, the thickness of the second sealing member 3b is set to the thickness of the first sealing member 3a. If the permanent deformation generated in the second seal member 3b is made smaller than this, the service life of the second seal member 3b will be extended, so that when the liquid leakage occurs due to the deterioration of the first seal member 3a. However, the outer second seal member 3b has not yet deteriorated, and liquid leakage can be prevented.

As in the third embodiment, it is preferable to set the thickness of the second seal member 3b to be larger than the thickness of the first seal member 3a in terms of preventing liquid leakage, but conversely, the second seal member It is also possible to set the thickness of the first seal member 3a to be larger than the thickness of 3b so as to reduce the permanent distortion generated in the first seal member 3a.
Since other configurations and operational effects are the same as those of the second embodiment, detailed description thereof is omitted here.

  The present invention is not limited to the individual configurations of the above-described first to third embodiments, and it is needless to say that the configurations of the first to third embodiments can be appropriately combined. For example, in the configuration of the first embodiment, the distance between the opposing surfaces is changed at each position of the first and second seal members 3a and 3b as in the second embodiment, or both the seal members 3a as in the third embodiment. , 3b can be changed so that an appropriate pressure is applied to the seal members 3a, 3b. Further, in the second and third embodiments, as described in the first embodiment, it is possible to install a liquid leak sensor between the first and second seal members 3a and 3b.

  In the first to third embodiments, the semiconductor element constituting the semiconductor module 1 has been described as including the power switching element 11 such as an IGBT. However, the present invention is not limited to this. For example, the present invention can be similarly applied to a semiconductor device including the semiconductor module 1 in which a plurality of highly integrated and high-speed logic elements are packaged.

It is a longitudinal cross-sectional view which shows the principal part of the semiconductor device in Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the semiconductor device in Embodiment 2 of this invention. It is a characteristic view which shows the relationship between the crushing rate of a sealing member, and compression set. It is sectional drawing which shows the principal part of the semiconductor device in Embodiment 3 of this invention. It is a characteristic view which shows the relationship between the thickness of a sealing member, and permanent set.

Explanation of symbols

1 semiconductor module, 11 switching element (semiconductor element),
15 module base, 16 module case, 2 liquid cooling member, 21 flow path,
22 opening, 23 mounting groove, 24 mounting groove, 25 peripheral wall, 3a first seal member,
3b Second seal member, La to Lf Distance between opposing surfaces.

Claims (4)

A semiconductor module on which a semiconductor element is mounted; and a liquid cooling member having a cooling liquid flow passage therein and having an opening formed so that a part of the flow passage is exposed to the outside. In the direct liquid cooling type semiconductor device in which the liquid cooling member and the liquid cooling member are integrally joined via two sealing members, and the cooling surface of the semiconductor module faces the opening of the flow path,
The liquid cooling member has a peripheral wall portion facing a peripheral side surface substantially orthogonal to the cooling surface of the semiconductor module, and one of the two seal members is an opening of the liquid cooling member. The other sealing member is mounted between the opposing surface of the peripheral side surface of the semiconductor module and the peripheral wall portion formed on the liquid cooling member. A semiconductor device, wherein the semiconductor device is inserted into the semiconductor device. A semiconductor module on which a semiconductor element is mounted; and a liquid cooling member having a cooling liquid flow passage therein and having an opening formed so that a part of the flow passage is exposed to the outside. In the direct liquid cooling type semiconductor device in which the liquid cooling member and the liquid cooling member are integrally joined via two sealing members, and the cooling surface of the semiconductor module faces the opening of the flow path,
The two seal members are both interposed between the opposing surfaces of the cooling surface side of the semiconductor module and the opening forming side of the liquid cooling member, and between the opposing surfaces of the semiconductor module and the liquid cooling member. A semiconductor device characterized in that the pressure applied to each seal member is made different by making the distances different from each other at the position of each seal member. Instead of making the distance between the opposing surfaces of the semiconductor module and the liquid cooling member different at the position of each seal member, the pressure applied to each seal member is made different by making the thickness of each seal member different from each other. The semiconductor device according to claim 2, wherein: Of the two seal members, the additional stress applied to each seal member is set so that the permanent strain generated in the other seal member located on the outer side is smaller than the permanent strain generated in one seal member located on the close side of the opening. 4. The semiconductor device according to claim 1, wherein a pressure is set.

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