Semiconductor module

Abstract

To reduce the loss cost when a defect is found, and suppress the tilt of a substrate 3 integrated with a base when a semiconductor module 1 is attached to another member.SOLUTION: A semiconductor module 1 includes a semiconductor chip 2, a plurality of substrates 3 where the semiconductor chip 2 is mounted, a case 4 that holds the substrates 3, and a cover 5 that is fixed to the case 4 and covers an upper surface of the case 4. The substrate 3 includes an insulating layer 3A, a wiring layer 3B provided on a front surface side of the insulating layer 3A and having the semiconductor chip 2 mounted thereon, and a metal layer 3C provided on a back surface side of the insulating layer 3A and serving as a heat release surface. The case 4 includes an outer peripheral part column 4A that is attached to the substrates 3 in an outer peripheral region 10A when the substrates 3 are viewed entirely, and an inter-substrate column 4B that is attached to the substrates 3 in an adjacent region 10B where the substrates 3 are adjacent. The inter-substrate column 4B is pressed toward the substrates 3 as the cover 5 is fixed to the case 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor module. [Background technology]

[0002] The typical structure of a semiconductor module is one in which a substrate (insulating substrate) having an insulating layer, a wiring layer on the front side of the insulating layer on which a semiconductor chip is mounted, and a metal layer on the back side of the insulating layer is bonded to a base plate that functions as a heat sink via a bonding material such as solder.

[0003] On the other hand, in order to reduce the number of components, there is also a semiconductor module structure that uses a base-integrated substrate in which the metal layer on the back side of the substrate also functions as a base plate.

[0004] An example of technology relating to a semiconductor module using this base-integrated substrate is Patent Document 1. In Figures 1 and 2 and paragraphs 0014 to 0015 of Patent Document 1, a structure is described in which an insulating substrate (1) is composed of an insulating layer (1b), a circuit pattern (1c) provided on the front side of the insulating layer (1b), and an Al plate (1a) provided on the back side of the insulating layer (1b), and an IGBT (3) and a FWDi (freewheeling diode) (4) are respectively joined to the circuit pattern (1c) using solder (2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-135105 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the case of the technology described in Patent Document 1, there is only one insulating substrate (1) that is an integrated base substrate. Therefore, if a defect is discovered during inspection during manufacturing, for example, the entire substrate must be discarded together with the semiconductor chips mounted thereon, such as IGBTs (3), resulting in a problem of high waste costs.

[0007] For this reason, it is conceivable to divide the base-integrated board into multiple boards for use. However, if this is done, when the semiconductor module is attached to another component, only the outer periphery of the multiple boards as a whole is pressed by the case, and not the areas where the multiple boards are adjacent to each other, which can lead to the problem of the boards tilting.

[0008] The problem that the present invention aims to solve is to provide a semiconductor module that uses a base-integrated substrate, in which loss costs are small even if a defect is found, and in which tilting of the substrate when the semiconductor module is attached to another member can be suppressed. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the semiconductor module of the present invention comprises a semiconductor chip, a plurality of substrates each having the semiconductor chip mounted thereon, a case for holding the plurality of substrates, and a cover fixed to the case and covering the top surface of the case, wherein the substrates have an insulating layer, a wiring layer provided on the front side of the insulating layer and having the semiconductor chip mounted thereon, and a metal layer provided on the back side of the insulating layer and serving as a heat dissipation surface, and the case has peripheral supports adhered to the plurality of substrates in their peripheral regions when the plurality of substrates are viewed as a whole, and inter-substrate supports adhered to the plurality of substrates in adjacent regions where the plurality of substrates are adjacent, and the inter-substrate supports are pressed in the direction of the plurality of substrates when the cover is fixed to the case. [Effects of the Invention]

[0010] According to the present invention, in a semiconductor module using a base-integrated substrate, even if a defect is found, loss costs are small and tilting of the substrate when the semiconductor module is attached to another member can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 3 is a cross-sectional view illustrating a state in which the semiconductor module of the first embodiment is attached to another member. [Figure 2] FIG. 10 is a cross-sectional view illustrating a state in which the semiconductor module of the comparative example is attached to another member. [Figure 3] 10A to 10C are cross-sectional views illustrating a method for manufacturing a semiconductor module according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view illustrating a state in which the semiconductor module of the second embodiment is attached to another member. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing and each embodiment, the same or similar components are designated by the same reference numerals, and redundant explanations will be omitted. [Example]

[0013] FIG. 1 is a cross-sectional view illustrating a state in which the semiconductor module of the first embodiment is attached to another member.

[0014] The semiconductor module 1 of this embodiment has a semiconductor chip 2, multiple substrates 3 on which the semiconductor chip 2 is mounted, a case 4 that holds the multiple substrates 3, and a cover 5 that is fixed to the case 4 and covers the top surface of the case 4.

[0015] The semiconductor module 1 of this embodiment also has a sealing resin (not shown) that is provided inside the case 4 and seals the semiconductor chip 2 and the plurality of substrates 3. As the sealing resin, for example, soft silicone gel or hard epoxy resin can be used.

[0016] The semiconductor chip 2 may be, for example, a switching element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a diode. While Fig. 1 shows an example in which one semiconductor chip 2 is mounted on one substrate 3, multiple semiconductor chips 2 may be mounted on one substrate 3.

[0017] The substrate 3 is an integrated base substrate (insulating substrate) that also functions as a base plate. Specifically, the substrate 3 has an insulating layer 3A, a wiring layer 3B provided on the front side of the insulating layer 3A and on which the semiconductor chip 2 is mounted, and a metal layer 3C provided on the back side of the insulating layer 3A and serving as a heat dissipation surface. The insulating layer 3A can be made of, for example, resin or ceramic. Using resin as the insulating layer 3A is preferable because it reduces costs compared to using ceramic. The semiconductor chip 2 is bonded to the wiring layer 3B via a bonding material 7 such as solder or sintered metal.

[0018] In this embodiment, the entire product is not made up of a single substrate 3, but rather multiple substrates 3 are used. Therefore, even if a defect is found during inspection during manufacturing, only the substrate 3 in which the defect is found needs to be discarded, thereby reducing loss costs.

[0019] The case 4 has peripheral supports 4A bonded to the plurality of substrates 3 in a peripheral region 10A when the plurality of substrates 3 are viewed as a whole, and inter-substrate supports 4B bonded to the plurality of substrates 3 in an adjacent region 10B where the plurality of substrates 3 are adjacent to each other. The case 4 is bonded to the plurality of substrates 3 via adhesive 6, thereby holding the plurality of substrates 3 in the case 4. The case 4 also has mounting holes 4C for attaching the semiconductor module 1 to another member.

[0020] The cover 5 is fixed to the upper surface of the case 4 via an adhesive 6 and covers the upper surface of the case 4 .

[0021] In this embodiment, the cover 5 is fixed to the case 4, and thus the inter-board supports 4B are pressed in the direction of the plurality of boards 3 as shown by the pressing force 9 in FIG.

[0022] Specifically, the semiconductor module 1 of this embodiment has an elastic member 8 between the inter-board supports 4B and the cover 5, and the inter-board supports 4B are pressed toward the plurality of boards 3 via the elastic member 8 when the cover 5 is fixed to the case 4. The elastic member 8 can be, for example, a spring or a rubber-like elastic member. When a spring is used, it may be made of metal or of another material. If the cover 5 and the inter-board supports 4B come into direct contact, there is a problem in that they may separate due to vibration. Therefore, by providing the elastic member 8, it functions as a buffer material, solving this problem.

[0023] The effect of inter-board support 4B being pressed toward multiple boards 3 will be described using a comparative example in FIG.

[0024] FIG. 2 is a cross-sectional view illustrating a state in which the semiconductor module of the comparative example is attached to another member.

[0025] The semiconductor module 1 of the comparative example differs from the first embodiment in that the inter-board supports 4B are not pressed in the direction of the plurality of boards 3.

[0026] The semiconductor module 1 is attached to another component, such as a heat sink 20, using screws 22 inserted into mounting holes 4C in the case 4. At this time, as a result of the pressure applied by the screws 22, the multiple substrates 3 are strongly pressed against the outer peripheral region 10A side closer to the screws 22, causing the adjacent region 10B side farther from the screws 22 to lift and tilt, resulting in a problem of degraded flatness of the multiple substrates 3. Therefore, it is necessary to thicken the thermal interface material 21 (TIM), such as grease, provided between the metal layer 3C on the back side of the substrate 3 and the heat sink 20, which increases the thermal resistance. Furthermore, temperature fluctuations occur as the semiconductor module 1 operates, and repeated temperature fluctuations can cause deformation, potentially resulting in pumping out of the thermal interface material 21, such as grease.

[0027] 1, by pressing the inter-board supports 4B toward the plurality of boards 3, tilting of the boards 3 can be prevented when the semiconductor module 1 is attached to another member. Furthermore, because tilting of the boards 3 can be prevented, the flatness of the plurality of boards 3 remains high and stable, and there is no need to increase the thickness of the thermally conductive material 21, which prevents an increase in thermal resistance. Pump-out of the thermally conductive material 21 can also be prevented.

[0028] As explained above, according to this embodiment, even if a defect is found in a semiconductor module 1 using a base-integrated substrate 3, the loss cost is small, and tilting of the substrate 3 when attaching the semiconductor module 1 to another component can be prevented. [Example]

[0029] Fig. 3 is a cross-sectional view illustrating a method for manufacturing the semiconductor module of Example 2. Fig. 4 is a cross-sectional view illustrating a state in which the semiconductor module of Example 2 is attached to another member.

[0030] The second embodiment is a modification of the first embodiment, and differs in the way that the cover 5 presses the inter-board support 4B.

[0031] Specifically, in this embodiment, as shown in Fig. 3, cover 5 has a warp that convexly faces inter-board supports 4B when not fixed to case 4, and as shown in Fig. 4, cover 5 presses inter-board supports 4B when fixed to case 4. More specifically, when cover 5 is fixed to case 4, the warp of cover 5 is small and flat, generating residual stress. Pressing force 9 caused by this residual stress causes cover 5 to press inter-board supports 4B.

[0032] As shown in FIG. 4, the cover 5 and the inter-board support 4B may be bonded together with an adhesive 6, or an elastic member 8 may be provided between the inter-board support 4B and the cover 5 as in Example 1.

[0033] In this embodiment, the same effects as in the first embodiment can be obtained.

[0034] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the embodiments, and various modifications are possible within the scope of the technical concept of the present invention. In addition, some or all of the configurations described in each embodiment may be combined and applied. [Explanation of symbols]

[0035] 1: Semiconductor module 2: Semiconductor chip 3: Circuit board 3A: Insulating layer 3B: Wiring layer 3C: Metal layer 4: Case 4A: Periphery support 4B: Support between boards 4C: Mounting hole 5: Cover 6: Adhesive 7: Bonding material 8: Elastic member 9:Pressure 10A: Outer area 10B: Adjacent areas 20: Heat sink 21: Thermal conductive materials 22: Screw

Claims

1. A semiconductor chip; a plurality of substrates on which the semiconductor chips are mounted; a case for holding the plurality of substrates; a cover fixed to the case and covering the top surface of the case, the substrate has an insulating layer, a wiring layer provided on a front surface side of the insulating layer and on which the semiconductor chip is mounted, and a metal layer provided on a rear surface side of the insulating layer and serving as a heat dissipation surface; the case has peripheral supports adhered to the plurality of substrates in a peripheral region when the plurality of substrates are seen as a whole, and inter-substrate supports adhered to the plurality of substrates in adjacent regions where the plurality of substrates are adjacent to each other, The semiconductor module is characterized in that the inter-board supports are pressed toward the plurality of boards by the cover being fixed to the case.

2. In claim 1, an elastic member is provided between the inter-board support and the cover; The semiconductor module is characterized in that the inter-board supports are pressed toward the plurality of boards via the elastic member when the cover is fixed to the case.

3. In claim 2, The semiconductor module is characterized in that the elastic member is a spring.

4. In claim 3, The semiconductor module is characterized in that the elastic member is a metal spring.

5. In claim 2, The semiconductor module is characterized in that the elastic member is a rubber-like elastic member.

6. In claim 1, a cover that has a convex warp toward the inter-board support when not fixed to the case, and the cover presses against the inter-board support when fixed to the case.

7. In claim 1, The semiconductor module is characterized in that the insulating layer is made of resin.

8. In claim 1, The semiconductor module is characterized in that the insulating layer is made of ceramic.

9. In claim 1, The semiconductor module is characterized in that the case has mounting holes for mounting the semiconductor module to another member.

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