JP6404739B2 - Semiconductor module - Google Patents

Description

  The technology disclosed in this specification relates to a semiconductor module.

  Patent Document 1 discloses a semiconductor module having a semiconductor chip and a heat dissipation member. The heat radiating member has a plurality of two-dimensional heat diffusing members. Each two-dimensional heat diffusion member has a multilayer structure of graphite. Each graphite layer spreads in a two-dimensional shape (that is, a planar shape). Since each graphite layer has high thermal conductivity, each two-dimensional heat diffusion member has high thermal conductivity in a plane in which the graphite layer extends two-dimensionally. In Patent Document 1, each two-dimensional heat conducting member is disposed under a semiconductor chip so that a graphite layer extends radially. As a result, it is possible to efficiently dissipate heat from the semiconductor chip.

JP 2011-199202 A

  In the technique of Patent Document 1, two-dimensional heat diffusion members are in direct contact with each other. However, since the two-dimensional heat diffusion member is hard and the surface of the two-dimensional heat diffusion member is rough, it is difficult to bring the two-dimensional heat diffusion members into close contact with each other. Therefore, in the technique of Patent Document 1, there is a problem that a minute gap exists in the contact portion of the two-dimensional heat diffusion member, and heat conduction is inhibited at the contact portion.

  The semiconductor module disclosed in this specification includes a semiconductor chip and a heat dissipation member connected to the semiconductor chip. The heat radiating member has a higher heat conductivity in a first plane perpendicular to the first direction than the heat conductivity in the first direction, and the heat conductivity in the second direction is higher than the heat conductivity in the second direction. A second two-dimensional heat diffusion member having a high thermal conductivity in a second plane perpendicular to the second direction, and interposed between the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member. The first heat conducting member is included. In the cross section orthogonal to the stacking direction of the semiconductor chip and the heat dissipation member, the direction in which the first plane extends is different from the direction in which the second plane extends.

  In this semiconductor module, the first two-dimensional heat diffusing member and the second two-dimensional heat diffusing member are arranged so that the direction of the first plane is different from the direction of the second plane in the cross section perpendicular to the stacking direction of the semiconductor chip and the heat dissipation member. Has been placed. For this reason, the heat generated in the semiconductor chip can be diffused in different directions by the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member. Further, in this semiconductor module, the first heat conduction member is interposed between the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member. By selecting an appropriate material as the first heat conduction member, the first heat conduction member can be brought into close contact with the surface of the first two-dimensional heat diffusion member and the surface of the second two-dimensional heat diffusion member. Thereby, the heat conduction between the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member is improved. Therefore, the heat generated in the semiconductor chip can be effectively diffused by the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member. According to this semiconductor module, the heat dissipation performance of the semiconductor chip can be improved as compared with the conventional case.

1 is a longitudinal sectional view of a semiconductor module 10. FIG. FIG. 3 is a perspective view of a heat dissipation block 22 according to the first embodiment. FIG. 3 is a cross-sectional view of the heat dissipation block 22. The perspective view of the two-dimensional heat-diffusion member 60. FIG. The cross-sectional view corresponding to FIG. 3 of the thermal radiation block 22 of a modification. FIG. 6 is a perspective view of a heat dissipation block 22 according to the second embodiment. FIG. 6 is an exploded perspective view of a heat dissipation block 22 according to the second embodiment.

  A semiconductor module 10 according to the first embodiment illustrated in FIG. 1 includes a semiconductor chip 20 and a semiconductor chip 30.

  The semiconductor chip 20 is an IGBT. The electrodes on the lower surface of the semiconductor chip 20 are connected to the heat dissipation block 22 by solder. The lower surface of the heat dissipation block 22 is connected to the heat dissipation plate 50. The main electrode on the upper surface of the semiconductor chip 20 is connected to the metal block 24 by solder. The upper surface of the metal block 24 is connected to the heat dissipation block 26 by solder. The upper surface of the heat dissipation block 26 is connected to the heat dissipation plate 52. The signal electrode on the upper surface of the semiconductor chip 20 is connected to the signal terminal 28 by a wire.

  The semiconductor chip 30 is a diode. The electrodes on the lower surface of the semiconductor chip 30 are connected to the heat dissipation block 32 by solder. The lower surface of the heat dissipation block 32 is connected to the heat dissipation plate 50. The electrode on the upper surface of the semiconductor chip 30 is connected to the metal block 34 by solder. The upper surface of the metal block 34 is connected to the heat dissipation block 36 by solder. The upper surface of the heat dissipation block 36 is connected to the heat dissipation plate 52.

  The surfaces of the heat dissipation block 22 and the heat dissipation block 32 are covered with a metal layer. Therefore, the heat dissipation block 22 and the heat dissipation block 32 are electrically connected to each other. Further, the output electrode terminal 40 is connected to the heat dissipation block 32. The metal layers on the surfaces of the heat dissipation block 22 and the heat dissipation block 32 are electrically connected to the output electrode terminal 40. That is, the electrode on the lower surface of the semiconductor chip 20 and the electrode on the lower surface of the semiconductor chip 30 are connected to the output electrode terminal 40 via the heat dissipation blocks 22 and 32.

  The surfaces of the heat dissipation block 26 and the heat dissipation block 36 are covered with a metal layer. Therefore, the heat dissipation block 26 and the heat dissipation block 36 are electrically connected to each other. An input electrode terminal 42 is connected to the heat dissipation block 36. The metal layers on the surfaces of the heat dissipation block 26 and the heat dissipation block 36 are electrically connected to the output electrode terminal 40. That is, the main electrode on the upper surface of the semiconductor chip 20 and the electrode on the upper surface of the semiconductor chip 30 are connected to the input electrode terminal 42 via the metal blocks 24 and 34 and the heat dissipation blocks 22 and 32.

  The semiconductor chips 20 and 30 are covered with an insulating resin 54. The insulating resin 54 is formed over substantially the entire surface of the semiconductor module 10. However, a part of the signal terminal 28, a part of the output electrode terminal 40, a part of the input electrode terminal 42, the lower surface of the heat sink 50 and the upper surface of the heat sink 52 are exposed from the insulating resin 54.

  The semiconductor module 10 according to the first embodiment is characterized by the heat dissipation blocks 22, 26, 32, and 36. Further, the heat radiation blocks 22, 26, 32, and 36 have substantially the same configuration. Therefore, the heat dissipation block 22 will be described in detail below.

  FIG. 2 shows an enlarged perspective view of the semiconductor chip 20, the heat dissipation block 22, and the heat dissipation plate 50. Hereinafter, one direction parallel to the upper surface of the heat sink 50 is referred to as an x direction, and a direction parallel to the upper surface of the heat sink 50 and perpendicular to the x direction is referred to as a y direction. As shown in FIG. 2, the heat dissipation block 22 includes four blocks 22a to 22d. Each of the blocks 22a to 22d is formed in an isosceles right triangle shape when viewed from above. Each block 22a-22d is arranged on the heat sink 50 so that a right-angled corner | angular part may correspond. Each block 22a-22d is in contact with the other two adjacent blocks among the blocks 22a-22d.

  FIG. 3 shows a cross-sectional view of the heat dissipation block 22 taken along the dotted line III in FIG. As shown in FIG. 3, each of the blocks 22 a to 22 d includes a two-dimensional heat diffusion member 60 and a metal layer 62 that covers the surface of the two-dimensional heat diffusion member 60. As shown in FIG. 4, the two-dimensional heat diffusing member 60 is a laminate in which a large number of oriented graphite layers 60a are laminated. Each orientational graphite layer 60a extends in a two-dimensional shape (that is, a planar shape). More specifically, each orientational graphite layer 60a has a plane defined by the thickness direction (z direction in FIG. 4) of the two-dimensional heat diffusion member 60 and one direction (a direction in FIG. 4) orthogonal to the thickness direction. It extends in two dimensions along. The a direction is a direction from a right-angled corner of a right triangle toward a side facing the corner when the upper surface of the two-dimensional heat diffusion member 60 is viewed in plan. Each orientational graphite layer 60a is stacked in the b direction orthogonal to the a direction and the z direction. The oriented graphite layer 60a has extremely high thermal conductivity in the a direction and the z direction. On the other hand, since heat conduction is hindered at the interface of each oriented graphite layer 60a, the thermal conductivity between the oriented graphite layers 60a is not so high. Therefore, the two-dimensional heat diffusion member 60 has high thermal conductivity in the a direction and z direction, but is not so high in thermal direction in the b direction (that is, lower than thermal conductivity in the a direction and z direction). . As shown in FIG. 3, in the two-dimensional heat diffusion member 60 of the block 22a and the block 22c, the oriented graphite layer 60a extends in the x direction when viewed from above. That is, in the two-dimensional heat diffusion member 60 of the block 22a and the block 22c, the a direction coincides with the x direction. As shown in FIG. 3, in the two-dimensional heat diffusion member 60 of the block 22b and the block 22d, the orientation graphite layer 60a extends in the y direction when viewed from above. That is, in the two-dimensional heat diffusion member 60 of the block 22b and the block 22d, the a direction coincides with the y direction. That is, each of the blocks 22 a to 22 d is arranged so that the a direction extends radially from the center 23 of the heat dissipation block 22.

  As shown in FIG. 3, the two-dimensional heat diffusion member 60 of each of the blocks 22 a to 22 d is covered with a metal layer 62. Accordingly, the metal layer 62 is interposed between the two-dimensional heat diffusion members 60 of the blocks 22a to 22d. For example, the metal layer 62a of the block 22a and the metal layer 62b of the block 22b are interposed between the two-dimensional heat diffusion member 60 of the block 22a and the two-dimensional heat diffusion member 60 of the block 22b. The metal layer 62 is made of copper. Since the metal layer 62 has plasticity, it is in close contact with the surface of the two-dimensional heat diffusion member 60. Further, the metal layers 62 of the blocks 22a to 22d are also in close contact with each other. The metal layer 62 improves the thermal conductivity between the adjacent two-dimensional heat diffusion members 60.

  As shown in FIG. 2, the semiconductor chip 20 is connected to a position overlapping the center 23 (see FIG. 3) of the heat dissipation block 22. For this reason, when viewed along the stacking direction of the semiconductor chip 20 and the heat dissipation block 22, the a direction of each two-dimensional heat diffusion member 60 extends radially from the semiconductor chip 20 to the periphery thereof.

  When the semiconductor chip 20 is energized, the semiconductor chip 20 generates heat. Then, the heat generated in the semiconductor chip 20 is transmitted to the heat radiating plate 50 through the heat radiating block 22. Thereby, the temperature rise of the semiconductor chip 20 is suppressed. As described above, the two-dimensional heat diffusion member 60 of each heat dissipation block 22 has a high thermal conductivity in the thickness direction. For this reason, the heat generated in the semiconductor chip 20 is efficiently transmitted to the heat sink 50. Further, as described above, the two-dimensional heat diffusing member 60 of each block 22 is arranged such that the a direction having high thermal conductivity extends radially from the semiconductor chip 20. Therefore, the heat generated in the semiconductor chip 20 is transferred to the heat radiating plate 50 while being radially distributed by the two-dimensional heat diffusion members 60. Thus, since the heat generated in the semiconductor chip 20 is easily dispersed, the temperature rise of the semiconductor chip 20 is further suppressed. Further, as described above, the two-dimensional heat diffusion members 60 are connected to each other via the metal layer 62. For this reason, heat is easily transmitted between the two-dimensional heat diffusion members 60. Therefore, the heat generated in the semiconductor chip 20 is more easily diffused in the heat dissipation block 22. Thereby, the temperature rise of the semiconductor chip 20 is further suppressed. Therefore, in this semiconductor module 10, the temperature of the semiconductor chip 20 is unlikely to rise.

  Further, the two-dimensional heat diffusion member 60 expands due to a temperature rise. However, in the technique of the first embodiment, the entire surface of the two-dimensional heat diffusion member 60 is covered with the metal layer 62 that is copper. Since copper has a relatively high rigidity, the two-dimensional heat diffusion member 60 is restrained by the metal layer 62, and the thermal expansion of the two-dimensional heat diffusion member 60 is suppressed. Thereby, deterioration of the joint portion between the heat dissipation block 22 and another member is suppressed.

  The relationship between the structure of Example 1 and the structure of a claim is as follows. The two-dimensional heat diffusion member 60 of the block 22a according to the first embodiment is an example of a first two-dimensional heat diffusion member in the claims. In the two-dimensional heat diffusion member 60 of the block 22a of the first embodiment, the x direction perpendicular to the y direction and the thickness direction (that is, the first perpendicular to the first direction) are more than the thermal conductivity in the y direction (first direction). High thermal conductivity in the plane). The two-dimensional heat diffusion member 60 of the block 22b according to the first embodiment is an example of a second two-dimensional heat diffusion member in the claims. In the two-dimensional heat diffusion member 60 of the block 22b of the first embodiment, the y direction orthogonal to the x direction and the thickness direction (that is, the second orthogonal to the second direction) are more than the thermal conductivity in the x direction (second direction). High thermal conductivity in the plane). In a cross section orthogonal to the stacking direction of the semiconductor chip 20 and the heat dissipation block 22 (for example, the cross section shown in FIG. 3), the direction in which the first plane extends (that is, the x direction) is the direction in which the second plane extends (that is, the y direction). ) Is different.

  In the first embodiment, the heat dissipation block 22 is configured by the four blocks 22a to 22d. However, any number of two or more blocks may be employed. For example, the heat dissipation block 22 may be configured by three blocks 22e to 22g as shown in FIG. In FIG. 5, an angle of 120 ° is provided between each a direction of each two-dimensional heat diffusion member 60. When a semiconductor chip 20 having a hexagonal crystal structure (for example, a semiconductor chip made of SiC whose thickness direction is the c-axis) is installed at the center 25 of the heat dissipation block 22, the crystal structure of the semiconductor chip 20 is Heat can be diffused.

  FIG. 6 shows an enlarged perspective view of the semiconductor chip 20, the heat dissipation block 22, and the heat dissipation plate 50 of the semiconductor module of the second embodiment. The semiconductor module of the second embodiment is different from the semiconductor module 10 of the first embodiment in the structure of the heat dissipation block 22. Other configurations of the semiconductor module of the second embodiment are the same as those of the semiconductor module 10 of the first embodiment.

  As shown in FIGS. 6 and 7, the heat dissipation block 22 according to the second embodiment has a structure in which three metal layers 262 a to 262 b and two two-dimensional heat diffusion members 260 a and 260 b are alternately stacked. A metal layer 262 c is laminated on the heat sink 50. A two-dimensional heat diffusion member 260b is stacked on the metal layer 262c. A metal layer 262b is laminated on the two-dimensional heat diffusion member 260b. A two-dimensional heat diffusion member 260a is laminated on the metal layer 262b. A metal layer 262a is laminated on the two-dimensional heat diffusion member 260a. The semiconductor chip 20 is stacked on the metal layer 262a.

  As shown in FIG. 7, each of the two-dimensional heat diffusion members 260a and 260b is a laminated body in which a large number of oriented graphite layers 60a are laminated in the same manner as the two-dimensional heat diffusion member 60 of the first embodiment. In the two-dimensional heat diffusion member 260a, an oriented graphite layer 60a is laminated in the x direction. Therefore, each orientational graphite layer 60a of the two-dimensional heat diffusion member 260a extends in the y direction when viewed from above, and extends in the thickness direction when viewed in cross section. Therefore, the two-dimensional heat diffusion member 260a has a high thermal conductivity in the y direction and the thickness direction. In the two-dimensional heat diffusion member 260b, the oriented graphite layer 60a is laminated in the y direction. Therefore, each orientational graphite layer 60a of the two-dimensional heat diffusion member 260b extends in the x direction when viewed from above, and extends in the thickness direction when viewed in cross section. Therefore, the two-dimensional heat diffusion member 260b has a high thermal conductivity in the x direction and the thickness direction.

  The metal layers 262a to 262c are made of copper. The metal layer 262 a is interposed between the two-dimensional heat diffusion member 260 a and the semiconductor chip 20. Since the metal layer 262a has plasticity, it is in close contact with the upper surface of the two-dimensional heat diffusion member 260a. The metal layer 262a improves the thermal conductivity between the semiconductor chip 20 and the two-dimensional heat diffusion member 260a. The metal layer 262b is interposed between the two-dimensional heat diffusion member 260a and the two-dimensional heat diffusion member 260b. Since the metal layer 262b has plasticity, it is in close contact with the lower surface of the two-dimensional heat diffusion member 260a and the upper surface of the two-dimensional heat diffusion member 260b. The metal layer 262b improves the thermal conductivity between the two-dimensional heat diffusion member 260a and the two-dimensional heat diffusion member 260b. The metal layer 262c is interposed between the two-dimensional heat diffusion member 260b and the heat sink 50. Since the metal layer 262c has plasticity, it is in close contact with the lower surface of the two-dimensional heat diffusion member 260b. The metal layer 262c improves the thermal conductivity between the two-dimensional heat diffusion member 260b and the heat sink 50.

  Also in the semiconductor module of the second embodiment, the heat generated in the semiconductor chip 20 is transmitted to the heat radiating plate 50 through the heat radiating block 22. Thereby, the temperature rise of the semiconductor chip 20 is suppressed. As described above, the two-dimensional heat diffusion members 260a and 260b have high thermal conductivity in the thickness direction. For this reason, the heat generated in the semiconductor chip 20 is efficiently transmitted to the heat sink 50. In the xy plane, as described above, the two-dimensional heat diffusion member 260a has a high thermal conductivity in the y direction, and the two-dimensional heat diffusion member 260b has a high thermal conductivity in the x direction. Therefore, the heat generated in the semiconductor chip 20 is transferred to the heat radiating plate 50 while being dispersed in the x direction and the y direction by the two-dimensional heat diffusion members 260a and 260b. Thus, since the heat generated in the semiconductor chip 20 is easily dispersed, the temperature rise of the semiconductor chip 20 is further suppressed. Further, as described above, the two-dimensional heat diffusion member 260a and the two-dimensional heat diffusion member 260b are connected to each other through the metal layer 262b. For this reason, heat is easily transmitted between the two-dimensional heat diffusion member 260a and the two-dimensional heat diffusion member 260b. Therefore, the heat generated in the semiconductor chip 20 is easily transmitted by the heat radiating plate 50 through the heat radiating block 22. Thereby, the temperature rise of the semiconductor chip 20 is further suppressed. Therefore, in the semiconductor module of Example 2, the temperature of the semiconductor chip 20 is unlikely to rise.

  The relationship between the configuration of the second embodiment and the configuration of the claims is as follows. The two-dimensional heat diffusion member 260b according to the second embodiment is an example of a first two-dimensional heat diffusion member according to claims. In the two-dimensional heat diffusing member 260b of Example 2, the x direction perpendicular to the y direction and the thickness direction (that is, in the first plane perpendicular to the first direction) rather than the thermal conductivity in the y direction (first direction). High thermal conductivity. The two-dimensional heat diffusion member 260a according to the second embodiment is an example of a second two-dimensional heat diffusion member according to claims. In the two-dimensional heat diffusing member 260a of Example 2, the y direction and the thickness direction (that is, in the second plane orthogonal to the second direction) perpendicular to the x direction rather than the thermal conductivity in the x direction (second direction). High thermal conductivity. In a cross section orthogonal to the stacking direction of the semiconductor chip 20 and the heat dissipation block 22 (for example, a cross section in the xy plane of each of the two-dimensional heat diffusion members 260a and 260b), the direction in which the first plane extends (that is, the x direction) is the second. It is different from the direction in which the plane extends (that is, the y direction).

  In the semiconductor module of Example 2, the end surfaces of the two-dimensional heat diffusion members 260a and 260b are exposed. Good.

  In the semiconductor module of Example 2, two two-dimensional heat diffusion members 260a and 260b are stacked. However, three or more two-dimensional heat diffusion members may be stacked.

  In Examples 1 and 2 described above, the heat conducting member interposed between the two-dimensional heat diffusing members is a metal layer, but the heat conducting member is made of a non-metallic high heat conducting material such as ceramics. May be.

  The configurations of the semiconductor modules disclosed in this specification are listed below. Each configuration is useful independently.

  In an example of the technique disclosed in this specification, a semiconductor module includes a semiconductor chip and a heat dissipation member connected to the semiconductor chip. The heat radiating member is higher than the thermal conductivity in the first direction, the first two-dimensional heat diffusing member having a higher thermal conductivity in the first plane orthogonal to the first direction, and the thermal conductivity in the second direction. The second two-dimensional heat diffusion member having a high thermal conductivity in a second plane orthogonal to the second direction, and interposed between the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member. The first heat conducting member is provided. In the cross section orthogonal to the stacking direction of the semiconductor chip and the heat dissipation member, the direction in which the first plane extends is different from the direction in which the second plane extends.

  In an example of the technology disclosed in the present specification, the heat radiating member is a third two-dimensional heat diffusing member having a higher thermal conductivity in a third plane orthogonal to the third direction than the thermal conductivity in the third direction. And a second heat conducting member interposed between the second two-dimensional heat diffusing member and the third two-dimensional heat diffusing member. The first two-dimensional heat diffusing member and the second two-dimensional heat diffusing member are disposed adjacent to each other within the cross section perpendicular to the stacking direction. The second two-dimensional heat diffusing member and the third two-dimensional heat diffusing member are disposed adjacent to each other in the cross section perpendicular to the stacking direction. The semiconductor chip is disposed at a position overlapping the first two-dimensional heat diffusion member, the second two-dimensional heat diffusion member, and the third two-dimensional heat diffusion member when viewed along the stacking direction. . In the cross section orthogonal to the stacking direction, the direction in which the first plane extends, the direction in which the second plane extends, and the direction in which the third plane extends extend radially from the semiconductor chip.

  In an example of the technique disclosed in this specification, the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member are stacked along the stacking direction.

  In an example of the technique disclosed in this specification, the heat conducting member is copper.

The embodiments have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit 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 technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical usefulness by achieving one of them.

10: Semiconductor module 20: Semiconductor chip 22: Heat radiation block 50: Heat radiation plate 60: Two-dimensional heat diffusion member 60a: Oriented graphite layer 62: Metal layer

Claims (1)

A semiconductor module,
A semiconductor chip;
A heat dissipation member connected to the semiconductor chip,
Have
The heat dissipation member is
A first two-dimensional heat diffusion member having a higher thermal conductivity in a first plane perpendicular to the first direction than the thermal conductivity in the first direction;
A second two-dimensional heat diffusion member having a higher thermal conductivity in a second plane perpendicular to the second direction than the thermal conductivity in the second direction;
A first heat conduction member interposed between the first two-dimensional heat diffusion member and the second two-dimensional heat diffusion member ;
A third two-dimensional heat diffusing member having a higher thermal conductivity in a third plane perpendicular to the third direction than the thermal conductivity in the third direction;
A second heat conducting member interposed between the second two-dimensional heat diffusing member and the third two-dimensional heat diffusing member,
Have
The semiconductor chip as that of the cross section perpendicular to the stacking direction of the heat dissipation member, a direction that the first plane extends is, unlike the direction in which the second plane extends,
The first two-dimensional heat diffusing member and the second two-dimensional heat diffusing member are arranged adjacent to each other in the cross section perpendicular to the stacking direction;
The second two-dimensional heat diffusing member and the third two-dimensional heat diffusing member are disposed adjacent to each other in the cross section perpendicular to the stacking direction;
The semiconductor chip is disposed at a position overlapping the first two-dimensional heat diffusion member, the second two-dimensional heat diffusion member, and the third two-dimensional heat diffusion member when viewed along the stacking direction. ,
In the cross section perpendicular to the stacking direction, the direction in which the first plane extends, the direction in which the second plane extends, and the direction in which the third plane extends extend radially from the semiconductor chip.
Semiconductor module.

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