JP7087933B2 - Semiconductor device - Google Patents

Description

The present specification discloses a semiconductor device including a spring member that applies a load to the stacking unit in the stacking direction.

The semiconductor device disclosed in Patent Document 1 includes a laminated unit, a contact plate, and a spring member. In the stacking unit, the semiconductor module and the cooler for cooling the semiconductor module are alternately laminated. The abutment plate is arranged between the stacking unit and the spring member in the stacking direction. The spring member has a shape in which the central portion of the spring member is curved in an arc shape toward the contact plate side. The spring member applies a load to the stacking unit in the stacking direction via the contact plate.

Japanese Unexamined Patent Publication No. 2014-101936

In the above semiconductor device, a load is applied to the laminated unit from the central portion of the spring member via the contact plate. Therefore, the load applied to the laminated unit is maximum in the range overlapping the central portion of the spring member, and decreases as the distance from the range overlapping the central portion of the spring member increases. As a result, the adhesion between the semiconductor module and the cooler becomes uneven, and the cooling unevenness of the semiconductor module occurs.

This specification discloses a technique for suppressing cooling unevenness of a semiconductor module by suppressing unevenness of a load applied to a laminated unit.

The semiconductor device disclosed in the present specification abuts on a laminated unit in which a semiconductor module accommodating a semiconductor element and a cooler for cooling the semiconductor module are alternately laminated, and one end portion of the laminated unit in the stacking direction. The load is applied from the spring member to the stacking unit by abutting against the spring member that applies a load to the stacking unit toward the stacking direction and the central portion of the spring member in the direction orthogonal to the stacking direction. A fixing member for fixing the spring member in the added state is provided. The spring member before applying the load to the laminated unit is curved so as to be separated from the laminated unit from both ends of the spring member in the orthogonal direction toward the central portion. The spring member in a state where the load is applied to the laminated unit comes into contact with the laminated unit at the central portion and both ends of the spring member.

In the above configuration, when the spring member applies a load to the laminated unit, the spring member is deformed toward the laminated unit, and the central portion and both ends of the spring member are in contact with the laminated unit. In this case, the first load is applied to the laminated unit from the central portion of the spring member. Further, a second load for returning the spring member to the curved state is generated in the spring member, and the second load is applied from the spring member to the laminated unit. The first load is maximum at the central portion of the spring member and decreases as the distance from the central portion increases. The second load is maximum at both ends of the spring member and decreases as it separates from both ends. The total load applied from the spring member to the laminated unit is the total value of the first load and the second load, and is uniformized in the orthogonal direction. As a result, the semiconductor module and the cooler are uniformly in contact with each other in the orthogonal direction, and the semiconductor module can be uniformly cooled.

It is a side view of the semiconductor device of an Example. It is a perspective view of the spring member of an Example before pressurizing. It is a figure which shows the bending amount of the spring member of an Example before pressurizing. It is a figure which shows the distribution of the load applied to the laminated unit from the spring member of an Example.

(Example)
The semiconductor device 10 of the embodiment will be described with reference to FIGS. 1 to 3. The semiconductor device 10 of the embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle. Further, the semiconductor device 10 is mounted on a power conversion device constituting a power control unit of the vehicle. The semiconductor device 10 is housed in a housing (not shown).

As shown in FIG. 1, the semiconductor device 10 includes a laminating unit 20 and a pressurizing member 40. The stacking unit 20 includes a plurality of (4 in this embodiment) semiconductor modules 22 and a plurality of (5 in this embodiment) coolers 30. The semiconductor module 22 and the cooler 30 are alternately laminated in the Z direction. Hereinafter, the Z direction may be referred to as a stacking direction. Coolers 30 are located at both ends of the stacking unit 20 in the stacking direction. An insulating plate (not shown) is arranged between the semiconductor module 22 and the cooler 30.

Each of the semiconductor modules 22 is arranged parallel to the XY plane (that is, the plane orthogonal to the stacking direction). The semiconductor module 22 includes a main body 24 and three power terminals 26 (positive electrode terminal 26a, negative electrode terminal 26b, midpoint terminal 26c). The main body 24 has a flat plate shape. The main body 24 houses a semiconductor element (not shown) inside. The semiconductor element has an element structure and a diode such as, for example, an insulated gate type bipolar transistor (that is, an IGBT) and a metal oxide semiconductor electric field effect transistor (that is, a MOSFET). A positive electrode terminal 26a, a negative electrode terminal 26b, and a midpoint terminal 26c extend from the main body 24. The positive electrode terminal 26a, the negative electrode terminal 26b, and the midpoint terminal 26c are electrically connected to the semiconductor element. When a current flows through a semiconductor element, the semiconductor element generates heat. As a result, the semiconductor module 22 generates heat.

The cooler 30 has a flat plate shape. The cooler 30 is made of, for example, a metal material such as aluminum. Each of the coolers 30 is arranged parallel to the XY plane. The cooler 30 has a flow path inside. The coolers 30 adjacent to each other are connected by connecting pipes 32 and 34. The connecting pipes 32 and 34 extend parallel to the stacking direction. The connecting pipe 32 is arranged on one end side of the cooler 30 in the X direction, and the connecting pipe 34 is arranged on the other end side of the cooler 30 in the X direction. Each of the connecting pipes 32 and 34 has a flow path inside. The flow path of the connecting pipe 32 and the flow path of the connecting pipe 34 communicate with each of the flow paths of the cooler 30.

A refrigerant circulation device (not shown) is connected to the connecting pipes 32 and 34. The refrigerant circulation device sends out the liquid refrigerant to the cooler 30, and receives the liquid refrigerant discharged from the cooler 30. The liquid refrigerant is, for example, LLC (Long Life Coolant) or the like. The liquid refrigerant sent out from the refrigerant circulation device passes through the flow path of the connecting pipe 32 and is distributed to each of the flow paths of the cooler 30. The liquid refrigerant absorbs the heat of the semiconductor module 22 while passing through each of the flow paths of the cooler 30. After that, the liquid refrigerant passes through the flow path of the connecting pipe 34 and returns to the inside of the refrigerant circulation device. As a result, the semiconductor module 22 is cooled by the cooler 30.

The pressurizing member 40 is in contact with one end of the stacking unit 20 in the stacking direction. A cooler 30 is located at one end of the stacking unit 20 in the stacking direction, and hereinafter, the cooler 30 is referred to as a cooler 30a. The pressurizing member 40 is in contact with the cooler 30a.

The pressurizing member 40 includes a spring member 42 and a fixing member 44. The spring member 42 is in surface contact with the cooler 30a. Seen from the stacking direction, the spring member 42 overlaps with the semiconductor module 22. The spring member 42 applies a load to the cooler 30a in the stacking direction. The spring member 42 will be described in detail later. In the X direction (that is, the orthogonal direction orthogonal to the stacking direction), the fixing member 44 is in contact with the central portion 42a of the spring member 42. The central portion 42a of the spring member 42 is a portion corresponding to the intermediate position of the spring member 42 in the orthogonal direction. The fixing member 44 is in contact with a surface of the spring member 42 opposite to the surface of the spring member 42 in contact with the cooler 30a. A spring member 42 is arranged between the fixing member 44 and the cooler 30a. The fixing member 44 fixes the spring member 42 in a state where the spring member 42 applies a load to the cooler 30a. The fixing member 44 is fixed to the housing.

The spring member 42 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, the spring member 42 is curved before the load is applied to the cooler 30a. The spring member 42 is a spring plate. The spring member 42 is curved so as to be separated from both end portions 42b and 42c toward the central portion 42a with respect to the XY plane passing through both end portions 42b and 42c of the spring member 42. The spring member 42 is plane symmetric with respect to the YZ plane passing through the central portion 42a. The spring member 42 has an initial shape having a relationship between the bending amount shown in FIG. 3 and the length of the spring member 42. FIG. 3 shows the relationship between the bending amount of the spring member 42 when viewed from the Y direction and the length of the spring member 42. The length from one end 42b to the other end 42c of the spring member 42 is 50 mm. The central portion 42a of the spring member 42 is separated from the XY plane passing through both end portions 42b and 42c by 3 mm.

The spring member 42 is made of an elastic material. When both ends 42b and 42c of the spring member 42 are fixed and a load in the Z direction is applied to the spring member 42, the spring member 42 is deformed. Further, when the load applied to the spring member 42 becomes zero, the spring member 42 returns to the initial shape.

When a load in the Z direction is applied to the central portion 42a of the spring member 42, the deformation amount D of the spring member 42 is calculated by the following equation.
Deformation amount D = PL ³ {(3a / L)-(4a ³ / L ³ )} / 48EI
Here, P is a load [N] applied to the spring member 42. L is the length [m] of the spring member 42, which is 0.05 (that is, 50 mm). a is a length [m] from one end 42b of the spring member 42 to a predetermined position, and is a length [m] from the other end 42c to a predetermined position. a is a value of 0 or more and L / 2 or less, and in this embodiment, it is a value of 0 or more and 0.025 or less. E is the Young's modulus [Pa] of the spring member 42, which is 206 × ¹⁰⁹ . I is the moment of inertia of area [m ⁴ ] of the spring member 42, which is 4.03 × ^10-12 .

For example, when a load of 1000 N in the Z direction is applied to the central portion 42a of the spring member 42, the deformation amount D of the central portion 42a of the spring member 42 is 3 mm. At this time, the central portion 42a of the spring member 42 is deformed by 3 mm in the Z direction. As a result, the spring member 42 is deformed into a flat plate shape. Further, when a load of 2000 N in the Z direction is applied to the central portion 42a of the spring member 42, the deformation amount D of the central portion 42a of the spring member 42 is 6 mm. At this time, the central portion 42a of the spring member 42 is deformed by 6 mm in the stacking direction. The central portion 42a of the spring member 42 projects 3 mm from the XY plane passing through both end portions 42b and 42c to the side opposite to the side where the central portion 42a of the spring member 42 is located in the initial shape. The spring member 42 is curved so as to be separated from both end portions 42b and 42c toward the central portion 42a with respect to the XY plane passing through both end portions 42b and 42c.

Next, a procedure for applying a load to the laminating unit 20 using the pressurizing member 40 will be described. First, both ends 42b and 42c of the spring member 42 are brought into contact with the cooler 30a of the laminated unit 20. At this time, the central portion 42a of the spring member 42 is separated from the cooler 30a. The spring member 42 is curved from both end portions 42b and 42c toward the central portion 42a so as to be separated from the cooler 30a.

Next, a load of 2000 N is applied to the central portion 42a of the spring member 42 toward the cooler 30a. As a result, a load is applied from the spring member 42 to the cooler 30a. When a load is applied to the central portion 42a of the spring member 42, the spring member 42 is deformed so that the central portion 42a of the spring member 42 approaches the cooler 30a. The surface abuts on the cooler 30a. The spring member 42 is deformed from an initial shape to a flat plate shape. The central portion 42a and both end portions 42b, 42c of the spring member 42 are in contact with the cooler 30a. When the load applied to the central portion 42a of the spring member 42 exceeds 1000 N, that is, when a load larger than the load required to deform the spring member 42 from the initial shape to the flat plate shape is applied, the load applied from the central portion 42a of the spring member 42 The first load P1 is applied to the cooler 30a. The first load P1 will be described in detail later.

Next, with the spring member 42 applying a load to the cooler 30a, the fixing member 44 is brought into contact with the central portion 42a of the spring member 42. Next, the fixing member 44 is fixed to the housing. As a result, the fixing member 44 fixes the spring member 42 in a state where the spring member 42 applies a load to the cooler 30a.

Next, the load applied from the spring member 42 to the laminating unit 20 will be described. When the load applied to the central portion 42a of the spring member 42 exceeds 1000 N, the first load P1 is applied from the central portion 42a of the spring member 42 to the cooler 30a. As shown in FIG. 4, the first load P1 becomes maximum at the central portion 42a of the spring member 42. In FIG. 4, the relationship between the first load P1 and the length of the spring member 42 is shown by a broken line. The first load P1 becomes smaller as the distance from the central portion 42a of the spring member 42 increases. The first load P1 is zero at both ends 42b and 42c of the spring member 42.

Further, the spring member 42 is fixed by the fixing member 44 in a state of being deformed into a flat plate shape. Therefore, a second load P2 is generated on the spring member 42 for the spring member 42 to return to the initial shape. The spring member 42 is fixed by the fixing member 44, and the second load P2 is applied to the cooler 30a from the spring member 42. As shown in FIG. 4, the second load P2 is maximized at both ends 42b and 42c of the spring member 42. In FIG. 4, the relationship between the second load P2 and the length of the spring member 42 is illustrated by a alternate long and short dash line. The second load P2 applied to the cooler 30a from both ends 42b and 42c of the spring member 42 is equal to the first load P1 applied to the cooler 30a from the central portion 42a of the spring member 42. The second load P2 becomes smaller as the distance from both ends 42b and 42c of the spring member 42 increases. The second load P2 is zero at the central portion 42a of the spring member 42.

The total load P3 applied from the spring member 42 to the cooler 30a is the total value of the first load P1 and the second load P2. As shown in FIG. 4, the total load P3 is uniformized in the orthogonal direction. In FIG. 4, the relationship between the total load P3 and the length of the spring member 42 is shown by a solid line. Therefore, a uniform load is applied to the cooler 30a from the spring member 42 in the orthogonal direction. As a result, the semiconductor module 22 and the cooler 30 can be uniformly brought into contact with each other in the orthogonal direction. As a result, the semiconductor module 22 can be uniformly cooled by the cooler 30.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

10: Semiconductor device 20: Laminating unit 22: Semiconductor module 24: Main body 26: Power terminal 30: Cooler 30a: Cooler 32, 34 located at one end of the laminating unit 20: Connecting tube 40: Pressurizing member 42: Spring Member 42a: Central portion 42b, 42c: End portion 44: Fixing member P1: First load P2: Second load P3: Total load

Claims (1)

A laminated unit in which a semiconductor module accommodating a semiconductor element and a cooler for cooling the semiconductor module are alternately laminated, and a laminated unit.
A spring member that is in contact with one end of the stacking unit in the stacking direction and applies a load to the stacking unit in the stacking direction.
A fixing member is provided which abuts on the central portion of the spring member in an orthogonal direction orthogonal to the stacking direction and fixes the spring member in a state where the load is applied from the spring member to the stacking unit.
The laminated unit abuts on the first surface of the spring member at the one end portion of the laminated unit in the laminated direction.
The fixing member abuts on the second surface of the spring member opposite to the first surface.
The spring member before applying the load to the laminated unit is curved so as to be separated from the laminated unit from both ends of the spring member in the orthogonal direction toward the central portion.
A semiconductor device in which the spring member in a state where the load is applied to the laminated unit abuts on the laminated unit at the central portion and both ends of the spring member.

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