Semiconductor device

Abstract

To provide a semiconductor device capable of being reduced in size and weight by suppressing an overall increase in wall thickness of a case or suppressing a portion constituting a cooling channel from projecting most outward from the case, even with a configuration in which a cooling channel is provided in the case.SOLUTION: A semiconductor device (1) has a configuration in which a cooling channel (7) is provided in a case (5). A second distance (T2) between a first surface portion (51) of the case and a fourth surface portion (54) is greater than a first distance (T1) between the first surface portion (51) and a second surface portion (52), and a third distance (T3) between the first surface portion (51) and a third surface portion (53) is greater than the second distance (T2).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to semiconductor devices. [Background technology]

[0002] For example, electrified vehicles, specifically hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs, PHEVs), electric vehicles (EVs), and fuel cell vehicles (FCVs), include semiconductor devices for power conversion, such as inverters that drive drive motors and converters that boost battery power supply voltage. In recent years, there has been a trend toward smaller, higher-output, and lower-cost semiconductor devices, and water cooling has become the mainstream method for cooling power semiconductors that generate a lot of heat. For example, as shown in Patent Document 1, a structure is known in which a power semiconductor is mounted on a heat sink equipped with cooling fins, and the heat sink and case are assembled so that the cooling fins are housed in a case that forms a cooling flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7160216 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional cases, the bottom surface of the entire case is constructed as a single plane to meet the case thickness required to form the cooling flow path, resulting in a large overall case thickness. This results in an increase in the overall size and weight of the semiconductor device. Furthermore, as the number of components housed in the case increases or the mounting shapes of the semiconductor device to external devices become more diverse, it is expected that the shape of the bottom surface of the case will become more complex. However, no proposal has been made to reduce the size and weight of semiconductor devices by taking into account the configuration and arrangement of the cooling flow path.

[0005] The present disclosure aims to provide a semiconductor device that has a configuration in which a cooling flow path is provided within the case, but can be made smaller and lighter by preventing the overall thickness of the case from becoming too large or the part that forms the cooling flow path from protruding the most outside the case. [Means for solving the problem]

[0006] The semiconductor device according to the present disclosure includes: Power semiconductors, a heat sink on which the power semiconductor is provided and which has cooling fins; a case to which the heat sink is joined and which defines a cooling flow path between the heat sink and the case and in which the cooling fins are housed; the case has one surface to which the heat sink is joined and another surface opposite to the one surface, the one surface includes a first surface portion including a joint portion to be joined to the heat sink, Of the normal directions to the first surface portion, a direction in which the first surface portion faces is defined as one side of the normal direction, and a side opposite to the normal direction is defined as the other side of the normal direction, the other surface includes a second surface portion located on the other side of the joint in the normal direction, a third surface portion located closest to the other side in the normal direction, and a fourth surface portion located on the other side of the cooling channel in the normal direction, a second distance between a position of the first surface portion and a position of the fourth surface portion in the normal direction is greater than a first distance between a position of the first surface portion and a position of the second surface portion in the normal direction; The third distance between the position of the first surface portion and the position of the third surface portion in the normal direction is greater than the second distance. [Effects of the Invention]

[0007] According to the semiconductor device of the present disclosure, with respect to the position of the first surface portion including the joint of the case as a reference, the second distance to the position of the fourth surface portion is greater than the first distance to the position of the second surface portion in the normal direction, and further the third distance to the position of the third surface portion is greater than the second distance. This configuration allows for cooling channels to be formed within the case, while the bottom surface of the entire case becomes a single plane, which increases the overall thickness of the case or prevents the portion forming the cooling channels from protruding most outside the case, thereby enabling the semiconductor device to be made smaller and lighter. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view showing the outside of a case of a semiconductor device according to a first embodiment. [Figure 2] 2 is a cross-sectional view showing the aa cross section of the semiconductor device according to the first embodiment of the present invention in FIG. [Figure 3] FIG. 10 is a plan view showing the outside of the case of the semiconductor device according to the second embodiment. [Figure 4] 1. FIG. 5 is a cross-sectional view showing the bb cross section of the semiconductor device according to the second embodiment. [Figure 5] FIG. 11 is a plan view showing the outside of the case of the semiconductor device according to the third embodiment. [Figure 6] 1. FIG. 5 is a cross-sectional view showing the cc cross section of the semiconductor device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. First Embodiment A semiconductor device 1 according to a first embodiment will be described with reference to the drawings. Fig. 1 is a plan view showing the exterior of the case of the semiconductor device 1, and Fig. 2 is a cross-sectional view showing the aa cross section of the semiconductor device 1 in Fig. 1.

[0010] The semiconductor device 1 includes a power semiconductor 2, a heat sink 3, cooling fins 4, a case 5, a cooling flow path 7, other electric components 8, and the like.

[0011] The power semiconductor 2 incorporates a semiconductor element (not shown). The semiconductor element is, for example, a MOS-FET, an IGBT, or a diode, and the substrate is made of silicon or a next-generation semiconductor such as silicon carbide or gallium nitride.

[0012] The heat sink 3 is provided with seven cooling fins 4 protruding in a plate shape on the surface opposite to the surface bonded to the power semiconductor 2. The heat sink 3 is formed of a metal material with excellent thermal conductivity, and for example, it is preferable to use any one selected from the group consisting of aluminum (Al) and copper (Cu), or an alloy of any two or more types. The bottom surface of the power semiconductor 2 and the heat sink 3 are bonded using a metal or resin material, and a bonding method that bonds the entire contact surface by heating a bonding material, such as sinter bonding, solder bonding, or brazing, is desirable, which is expected to reduce thermal resistance.

[0013] At least some of the cooling fins 4, which are heat dissipation portions formed on the heat sink 3, are preferably plate-like or pin-like projections with a large cooling area, and for example, pin fins with a narrow pitch may be formed by forging.

[0014] The case 5 is joined to the heat sink 3 via a joint 6, and a cooling channel 7 that houses the cooling fins 4 is defined between the heat sink 3 and the case 5. This cooling channel 7 extends in a direction perpendicular to the plane of the paper in FIG. 2, and a cooling medium such as water or oil (not shown) flows through this cooling channel 7. The cooling medium (not shown) is sealed on both sides along the cooling channel 7 by the joint 6. Here, the case 5 is formed from a metal material with excellent thermal conductivity, and for example, it is preferable to use any one type selected from the group consisting of aluminum (Al) and copper (Cu), or an alloy of any two or more types.

[0015] The joint 6 that seals the heat sink 3 and the case 5 is preferably formed by applying external energy, such as friction stir welding (FSW) using a rotary tool or laser welding, and is a base material joint with high joint strength in which the metal melts deep inside. In this case, the energy for the FSW rotary tool or laser welding is preferably applied from the second surface portion 52 side of the case 5. The joint 6 may also be provided with a sealing member such as an O-ring made of rubber, a metal gasket, or liquid packing for sealing.

[0016] On one side of the case 5, a surface portion including the joint 6 is defined as a first surface portion 51, and a direction parallel to a normal to the first surface portion 51 is defined as a normal direction X. In this normal direction X, the direction in which the first surface portion 51 faces is defined as one side X1, and the opposite direction is defined as the other side X2. Furthermore, on the other side of the case 5, a surface portion located on the other side X2 of the joint 6 is defined as a second surface portion 52, a surface portion located closest to the other side X2 is defined as a third surface portion 53, and a surface portion located on the other side X2 of the cooling channel 7 is defined as a fourth surface portion 54. Furthermore, on one side of the case 5, a surface portion located on one side X1 of the third surface portion 53 is defined as a fifth surface portion 55.

[0017] Similar to the cooling flow path 7, the fourth surface portion 54 also extends in a direction perpendicular to the plane of the drawing. On the other surface of the case 5, a second surface portion 52 and a third surface portion 53 are provided on both sides of the fourth surface portion 54, in that order from the inside.

[0018] When considering the size, weight, etc. of the semiconductor device 1, attention is focused on the arrangement of each surface portion in the normal direction X. Using the position of the first surface portion of the case 5 in the normal direction X as a reference, the distance between the position of the first surface portion 51 and the position of the second surface portion 52 is defined as a first distance T1, the distance between the position of the first surface portion 51 and the position of the fourth surface portion is defined as a second distance T2, and the distance between the position of the first surface portion 51 and the position of the third surface portion 53 is defined as a third distance T3. The case 5 is configured such that the second distance T2 is greater than the first distance T1, and the third distance T3 is greater than the second distance T2. Furthermore, the position of the fifth surface portion 55 is located on the other side X2 of the position of the first surface portion 51 in the normal direction X.

[0019] Here, the second distance T2 is the distance required to form the cooling flow path. The third distance T3 is the distance required to accommodate an increase in the number of components housed in the case or a diversification of mounting shapes of the semiconductor device to external devices. The first distance T1 is configured to be smaller than the second distance T2. This prevents the overall thickness of the case 5 from increasing. Furthermore, the second distance T2 is configured to be smaller than the third distance T3. This prevents the portion forming the cooling flow path from protruding most outside the case. That is, the power semiconductor 2 generally has a low height in the normal direction X, and by making the second distance T2 small, the portion forming the cooling flow path is prevented from protruding most outside the case. Furthermore, by configuring the fifth surface portion 55 to be located closer to the other side X2 than the first surface portion, a larger space can be secured within the case to accommodate other electrical components 8, etc., and the case thickness in this portion is prevented from increasing.

[0020] The other electric component 8 is housed in the case 5 together with the power semiconductor 2, and is arranged on one side X1 of the fifth surface portion 55. The other electric component 8 is, for example, a capacitor module, but is not limited to this and may be a component that constitutes part of an electric circuit, such as a terminal block or a connector, and these components generally have a height in the normal direction X greater than that of the power semiconductor 2. The lid 9 is joined to the case 5 so as to cover the opening of the case 5.

[0021] According to this embodiment, as described above, by focusing on the arrangement of each surface portion in the normal direction X, the overall thickness of the case 5 is prevented from increasing, and the portion forming the cooling flow path is prevented from protruding most outside the case. Furthermore, a large space can be secured inside the case to accommodate other electrical components 8, and the case thickness at that portion is also prevented from increasing. As a result, the semiconductor device 1 can be made smaller and lighter while still providing a cooling flow path inside the case 5.

[0022] Furthermore, according to this embodiment, by configuring the thickness corresponding to the first distance T1 to be smaller than the thickness corresponding to the second distance T2, it becomes easier to join the case 5 and the heat sink 3 by applying energy from the second surface portion 52 side, and the number of parts can be reduced compared to mechanical joining such as screw fastening, thereby improving productivity.

[0023] In FIG. 2, the first surface portion 51 is configured to contact the end of the heat sink 3, but the contact area is not limited to this. Also, in FIG. 2, the second surface portion 52 is configured to cover the entire surface of the joint 6, but this configuration is not limited to this. Also, in FIG. 2, the fourth surface portion 54 is configured as a single plane that covers the entire surface of the cooling flow path 7, but this configuration is not limited to this. Also, in FIG. 2, the third surface portion 53 is provided on both sides of the cooling flow path, but this is not limited to this.

[0024] 2. Second Embodiment Next, a semiconductor device 1 according to a second embodiment will be described with reference to the drawings. Fig. 3 is a plan view showing the exterior of the case of the semiconductor device 1, and Fig. 4 is a cross-sectional view showing the bb cross section of the semiconductor device 1 in Fig. 3. Description of components that are the same as those in the first embodiment will be omitted. The basic configuration of the semiconductor device 1 according to this embodiment is the same as that of the first embodiment, but differs from the first embodiment in that it has a rib structure 10 on the fourth surface portion 54 and the second surface portion 52 of the case 5, as shown in Figs. 3 and 4.

[0025] The step surface 56 is a portion that connects the third surface portion 53 and the second surface portion 52 that are provided on both sides of the case 5, and is provided so as to face each other.

[0026] The rib structure 10 is provided to protrude from the fourth surface portion 54 and the second surface portion 52 of the case 5 toward the other side X2, and extends between the step surfaces 56 on both sides and is connected to each step surface 56. This rib structure 10 does not protrude toward the other side X2 beyond the position of the third surface portion 53 in the normal direction X. The rib structure 10 is formed of a metal material with excellent thermal conductivity, such as any one or an alloy of two or more types selected from the group consisting of aluminum (Al) and copper (Cu), and is preferably made of the same material as the case 5.

[0027] In Figures 3 and 4, the rib structure 10 is a rectangular protrusion and is provided in eight locations on the second surface portion 52 and the fourth surface portion 54, but the shape or quantity of the rib structure 10 is not limited to this.

[0028] According to this embodiment, the rigidity of the case 5 is increased and the mechanical reliability is improved without compromising the size and weight reduction of the semiconductor device 1. Furthermore, a path is formed for dissipating heat generated from other electric components 8 to the cooling flow path 7 of the case 5 via the rib structure 10, thereby improving the heat dissipation performance of the semiconductor device 1.

[0029] 3. Embodiment 3 Next, a semiconductor device 1 according to a third embodiment will be described with reference to the drawings. Fig. 5 is a plan view showing the exterior of the case of the semiconductor device 1, and Fig. 6 is a cross-sectional view showing the cc cross section of the semiconductor device 1 in Fig. 5. Description of the same components as those in the first embodiment will be omitted. The basic configuration of the semiconductor device 1 according to this embodiment is the same as that of the first embodiment, but differs from the first embodiment in that it has a rib structure 11 on the fourth surface of the case as shown in Figs. 5 and 6.

[0030] The rib structure 11 is provided to protrude in the direction of the other side X2 only from the fourth surface portion 54 of the case 5, out of the fourth surface portion 54 and the second surface portion 52. This rib structure 11 does not protrude toward the other side X2 beyond the position of the third surface portion 53 in the normal direction X. The rib structure 11 is formed of a metal material with excellent thermal conductivity, such as any one or an alloy of two or more types selected from the group consisting of aluminum (Al) and copper (Cu), and is preferably made of the same material as the case 5.

[0031] In addition, in FIGS. 5 and 6, the rib structures 11 are rectangular projections provided at eight locations on the fourth surface portion 54, but the shape or number of the rib structures 11 is not limited to this.

[0032] According to this embodiment, the rigidity of the case 5 is increased and the mechanical reliability is improved without compromising the size and weight reduction of the semiconductor device 1. Furthermore, the case 5 and the heat sink 3 can be easily joined by applying energy from the second surface portion 52 side, and the number of parts can be reduced compared to mechanical joining such as screw fastening, thereby improving productivity.

[0033] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) Power semiconductors, a heat sink on which the power semiconductor is provided and which has cooling fins; a case to which the heat sink is joined and which defines a cooling flow path between the heat sink and the case and in which the cooling fins are housed; the case has one surface to which the heat sink is joined and another surface opposite to the one surface, the one surface includes a first surface portion including a joint portion to be joined to the heat sink, Of the normal directions to the first surface portion, a direction in which the first surface portion faces is defined as one side of the normal direction, and a side opposite to the normal direction is defined as the other side of the normal direction, the other surface includes a second surface portion located on the other side of the joint in the normal direction, a third surface portion located closest to the other side in the normal direction, and a fourth surface portion located on the other side of the cooling channel in the normal direction, a second distance between a position of the first surface portion and a position of the fourth surface portion in the normal direction is greater than a first distance between a position of the first surface portion and a position of the second surface portion in the normal direction; A semiconductor device, wherein a third distance between a position of the first surface portion and a position of the third surface portion in the normal direction is greater than the second distance.

[0034] (Appendix 2) The semiconductor device according to claim 1, wherein the bonding portion is formed by metal bonding by applying energy from the second surface portion side.

[0035] (Appendix 3) the first surface portion, the joint portion, and the second surface portion are provided on both sides of the fourth surface portion; A semiconductor device described in either Appendix 1 or 2, characterized in that the third surface portion is provided on both sides of the first surface portion, the joint portion, and the second surface portion, which are provided on both sides.

[0036] (Appendix 4) a rib structure protruding from the fourth surface portion and the second surface portions provided on both sides toward the other side in the normal direction; The semiconductor device described in Appendix 3, characterized in that the rib structure extends between the third surface portions provided on both sides and is connected to a step surface connecting the third surface portions and the second surface portions provided on each side.

[0037] (Appendix 5) The semiconductor device described in Appendix 3, characterized in that, of the fourth surface portion and the second surface portion, only the fourth surface portion is provided with a rib structure protruding to the other side of the normal direction.

[0038] (Appendix 6) A portion of the one surface located on one side of the third surface portion in the normal direction is a fifth surface portion, and the position of the fifth surface portion is located on the other side of the normal direction than the position of the first surface portion in the normal direction; 6. The semiconductor device according to claim 1, further comprising: another electrical component disposed on one side of the fifth surface in the normal direction.

[0039] Although various exemplary embodiments or examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this disclosure specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment. [Explanation of symbols]

[0040] 1: semiconductor device, 2: power semiconductor, 3: heat sink, 4: cooling fin, 5: case, 51: first surface portion, 52: second surface portion, 53: third surface portion, 54: fourth surface portion, 55: fifth surface portion, 6: joint portion, 7: cooling flow path, 8: other electrical component, 10: rib structure, 11: rib structure, X: normal direction, X1: one side, X2: other side, T1: first distance, T2: second distance, T3: third distance

Claims

1. Power semiconductors, a heat sink on which the power semiconductor is provided and which has cooling fins; a case to which the heat sink is joined and which defines a cooling flow path between the heat sink and the case and in which the cooling fins are housed; the case has one surface to which the heat sink is joined and another surface opposite to the one surface, the one surface includes a first surface portion including a joint portion to be joined to the heat sink, Of the normal directions to the first surface portion, a direction in which the first surface portion faces is defined as one side of the normal direction, and a side opposite to the normal direction is defined as the other side of the normal direction, the other surface includes a second surface portion located on the other side of the joint in the normal direction, a third surface portion located closest to the other side in the normal direction, and a fourth surface portion located on the other side of the cooling channel in the normal direction, a second distance between a position of the first surface portion and a position of the fourth surface portion in the normal direction is greater than a first distance between a position of the first surface portion and a position of the second surface portion in the normal direction; A semiconductor device, wherein a third distance between a position of the first surface portion and a position of the third surface portion in the normal direction is greater than the second distance.

2. 2. The semiconductor device according to claim 1, wherein the bonding portion is formed by metal bonding by applying energy from the second surface portion side.

3. the first surface portion, the joint portion, and the second surface portion are provided on both sides of the fourth surface portion; 3. The semiconductor device according to claim 2, wherein the third surface portion is provided on both sides of the first surface portion, the joint portion, and the second surface portion, which are provided on both sides.

4. a rib structure protruding from the fourth surface portion and the second surface portions provided on both sides toward the other side in the normal direction; 4. The semiconductor device according to claim 3, wherein the rib structure extends between the third surface portions provided on both sides and is connected to a step surface connecting the third surface portions and the second surface portions provided on each side.

5. 4. The semiconductor device according to claim 3, wherein a rib structure protruding to the other side in the normal direction is provided only on the fourth surface portion out of the fourth surface portion and the second surface portion.

6. A portion of the one surface located on one side of the third surface portion in the normal direction is a fifth surface portion, and the position of the fifth surface portion is located on the other side of the normal direction than the position of the first surface portion in the normal direction; 6. The semiconductor device according to claim 1, wherein another electrical component is disposed on one side of the fifth surface in the normal direction.

Images