Semiconductor module

Abstract

A first step surface (41) and second step surfaces (42) are provided on the inner surface side of a peripheral wall portion (32) of a case (30). The second step surfaces (42) extend parallel to the first step surface (41) on at least one of the outer side and the inner side of a substrate (10) relative to the first step surface (41). The second step surface (42) provided on the outer side of the substrate (10) relative to the first step surface (41) has a distance from a reference end surface (43) to the second step surface (42) that is shorter than the distance from the reference end surface (43) to the first step surface (41). The second step surface (42) provided on the inner side of the substrate (10) relative to the first step surface (41) has a distance from the reference end surface (43) to the second step surface (42) that is longer than the distance from the reference end surface (43) to the first step surface (41).

Description

Semiconductor Module

[0001] The present disclosure relates to a semiconductor module.

[0002] Patent Document 1 discloses a power semiconductor module including a base plate on which an insulating substrate is disposed, a case surrounding the insulating substrate and the base plate, and a spacer provided between the outer periphery of the base plate and the inner periphery of the case in contact with both. The document states that providing the spacer enables the same size case to be used for base plates of various sizes.

[0003] Patent No. 6391527

[0004] However, in the invention of Patent Document 1, since the same size case is used, it is necessary to produce a plurality of spacers corresponding to base plates of various sizes, which increases the number of spacer specifications, resulting in problems such as reduced production efficiency and complicated inventory management.

[0005] An object of the present disclosure is to enable a semiconductor module to be assembled using members of a single specification even for a plurality of substrates having different thicknesses.

[0006] A first aspect of the present disclosure is a semiconductor module including a substrate (10) and a case (30) that covers a mounting surface (11) of the substrate (10), wherein the case (30) has a facing portion (31) that faces the mounting surface (11) of the substrate (10) and a peripheral wall portion (32) that extends toward the substrate (10) along the periphery of the facing portion (31), and the inner surface of the peripheral wall portion (32) is provided with a first step surface (41) that abuts against the mounting surface (11) of the substrate (10) and a second step surface (41) that extends parallel to the first step surface (41) at least on one of the outer side and the inner side of the substrate (10) relative to the first step surface (41). 2), and when the second step surface (42) is provided outside the substrate (10) relative to the first step surface (41), the distance from a reference end surface (43) of the peripheral wall portion (32) on the opposite side to the opposing portion (31) to the second step surface (42) is shorter than the distance from the reference end surface (43) to the first step surface (41), and when the second step surface (42) is provided inside the substrate (10) relative to the first step surface (41), the distance from the reference end surface (43) to the second step surface (42) is longer than the distance from the reference end surface (43) to the first step surface (41).

[0007] In the first aspect, if a case (30) of one specification having a first step surface (41) and a second step surface (42) is produced, a semiconductor module can be assembled, for example, for a plurality of substrates (10) having different thicknesses, by abutting the mounting surface (11) of the substrate (10) against either the first step surface (41) or the second step surface (42).

[0008] A second aspect of the present disclosure is a semiconductor module according to the first aspect, wherein the first step surface (41) and the second step surface (42) are provided with groove portions (45) extending circumferentially of the peripheral wall portion (32).

[0009] In the second aspect, by filling the groove portion (45) with adhesive to bond the case (30) and the substrate (10), it is possible to prevent the adhesive from spilling out from between the mounting surface (11) of the substrate (10) and the first step surface (41) or the second step surface (42).

[0010] In a third aspect of the present disclosure, in the semiconductor module of the first or second aspect, a plate-shaped conductive member (15) is provided on the surface of the substrate (10) opposite to the mounting surface (11), and the reference end surface (43) and the surface of the conductive member (15) opposite to the substrate (10) are arranged on the same plane.

[0011] In the third aspect, when the case (30) is fixed to, for example, the heat sink (20) by screws, it is possible to prevent stress from being applied to the substrate (10).

[0012] A fourth aspect of the present disclosure is a semiconductor module according to any one of the first to third aspects, wherein a distance h from a point of a component (14) mounted on the substrate (10) closest to the opposing portion (31) to the mounting surface (11) of the substrate (10), a distance H from the reference end face (43) to the opposing portion (31), a distance D1 from the reference end face (43) to the first step surface (41), and a distance D2 from the reference end face (43) to the second step surface (42) satisfy the conditions D1<H-h and D2<H-h.

[0013] In the fourth aspect, even when the mounting surface (11) side of the substrate (10) is abutted against either the first step surface (41) or the second step surface (42), interference of the component (14) with the opposing portion (31) of the case (30) can be suppressed.

[0014] A fifth aspect of the present disclosure is a semiconductor module according to any one of the first to fourth aspects, wherein the first step surface (41) and the second step surface (42) extend along the circumferential direction of the peripheral wall portion (32).

[0015] In the fifth aspect, the peripheral edge of the substrate (10) is pressed by the first step surface (41) or the second step surface (42), thereby making it possible to prevent the substrate (10) from tilting.

[0016] Fig. 1 is a side cross-sectional view showing the configuration of a semiconductor module according to this embodiment. Fig. 2 is a side cross-sectional view showing a state in which a substrate is in contact with a first step surface. Fig. 3 is a side cross-sectional view showing a state in which a substrate is in contact with a second step surface provided on the outer side of the substrate than the first step surface. Fig. 4 is a side cross-sectional view showing a state in which a substrate is in contact with a second step surface provided on the inner side of the substrate than the first step surface.

[0017] <Overall Configuration> As shown in FIG. 1, the semiconductor module (1) includes a substrate (10), a semiconductor chip (13), a conductive member (15), and a case (30).

[0018] The substrate 10 is made of an insulating material such as ceramics or aluminum nitride. A metal pattern 12 is formed on a mounting surface 11 of the substrate 10. A semiconductor chip 13 is mounted on the metal pattern 12.

[0019] The semiconductor chip (13) is, for example, an insulated gate bipolar transistor (IGBT) or a diode. In the example shown in Figure 1, two semiconductor chips (13) are provided. The semiconductor chips (13) are connected to each other by connecting wires (14). The semiconductor chips (13) and the metal pattern (12) are connected by connecting wires (14).

[0020] One end of an external pin 16 is electrically connected to the metal pattern 12. The other end of the external pin 16 extends to protrude outside the case 30. The other end of the external pin 16 is connected to a control board (not shown).

[0021] The conductive member (15) is provided on the surface of the substrate (10) opposite the mounting surface (11). The conductive member (15) is formed in a plate shape. The conductive member (15) is a metal layer made of, for example, copper or aluminum. The conductive member (15) is in thermal contact with the heat sink (20) via grease (21).

[0022] The heat sink (20) is made of a heat conductive material such as copper, aluminum, etc. The heat sink (20) and a flange portion (33) of the case (30), which will be described later, are fastened together by fastening screws (50).

[0023] <Case> The case (30) is made of, for example, an insulating resin material. The case (30) covers the mounting surface (11) of the substrate (10) so as to define an internal space (35). A sealant (36) is sealed in the internal space (35) of the case (30). The sealant (36) covers the metal pattern (12), the semiconductor chip (13), and the connection wiring (14).

[0024] The case (30) has a facing portion (31), a peripheral wall portion (32), and a flange portion (33). The facing portion (31) faces the mounting surface (11) of the board (10). The peripheral wall portion (32) extends toward the board (10) along the peripheral edge of the facing portion (31). The flange portion (33) protrudes outward along the peripheral edge of the peripheral wall portion (32) on the side opposite to the facing portion (31).

[0025] A plurality of stepped surfaces formed in a staircase pattern are provided on the inner surface of the peripheral wall portion (32). In the example shown in Fig. 2, three stepped surfaces are provided. Of the three stepped surfaces, the second stepped surface counting from the outside of the case (30) is in contact with the mounting surface (11) of the substrate (10). Hereinafter, in Fig. 2, the stepped surface that is in contact with the mounting surface (11) of the substrate (10) is referred to as a first stepped surface (41). The remaining stepped surface is referred to as a second stepped surface (42).

[0026] In the example shown in Fig. 2, the second step surface (42) is provided both on the outer side and the inner side of the substrate (10) relative to the first step surface (41). The second step surface (42) extends parallel to the first step surface (41).

[0027] The second step surface (42), which is provided on the outer side of the substrate (10) than the first step surface (41), has a distance from a reference end surface (43) on the peripheral wall portion (32) opposite the opposing portion (31) to the second step surface (42) that is shorter than the distance from the reference end surface (43) to the first step surface (41).

[0028] On the other hand, the second step surface (42), which is provided inside the substrate (10) relative to the first step surface (41), has a longer distance from the reference end surface (43) to the second step surface (42) than the distance from the reference end surface (43) to the first step surface (41).

[0029] The first step surface (41) and the second step surface (42) extend in the circumferential direction of the peripheral wall portion (32). The first step surface (41) and the second step surface (42) are provided with grooves (45). The grooves (45) extend in the circumferential direction of the peripheral wall portion (32).

[0030] In the example shown in Fig. 2, the mounting surface (11) of the substrate (10) abuts against the first step surface (41). Therefore, the groove (45) of the first step surface (41) is filled with an adhesive (46) to bond the case (30) and the substrate (10).

[0031] The reference end surface (43) of the case (30) and the surface of the conductive member (15) opposite the substrate (10) are arranged on the same plane. In the example shown in FIG. 2 , the thickness t1 of the substrate (10) is 700 μm. The thickness t2 of the conductive member (15) is 300 μm. In this case, the distance from the reference end surface (43) to the first step surface (41) may be set to 1000 μm.

[0032] This can prevent stress from being applied to the substrate (10) when the flange portion (33) of the case (30) is screwed to the heat sink (20).

[0033] In the example shown in Fig. 1, the connection wiring 14 connecting the two semiconductor chips 13 extends in a curved upward direction in a side view, and therefore, the point closest to the opposing portion 31 of the component mounted on the substrate 10 is the vertex of the curved connection wiring 14.

[0034] As shown in Figures 1 and 2, the distance h from the point of the component mounted on the board (10) closest to the opposing portion (31) to the mounting surface (11) of the board (10), the distance H from the reference end face (43) to the opposing portion (31), the distance D1 from the reference end face (43) to the first step surface (41), and the distance D2 from the reference end face (43) to the second step surface (42) are set to satisfy the conditions D1 < H-h and D2 < H-h.

[0035] In the present embodiment, the second step surface (42), which is provided on the substrate (10) more inward than the first step surface (41), has a longer distance from the reference end surface (43) to the second step surface (42) than the distance from the reference end surface (43) to the first step surface (41). Therefore, the distance to the inner second step surface (42) is set as D2 so as to satisfy the above-mentioned condition.

[0036] The thickness of the substrate 10 is determined by the physical properties of the insulating material and the size of the substrate 10. Here, the material properties include, for example, parameters such as linear expansion coefficient, Young's modulus, and stress resistance such as hardness, and electric field resistance. Thus, when different insulating materials are used for the substrate 10, the thickness of the substrate 10 will differ depending on the insulating material.

[0037] Hereinafter, a case where a substrate (10) and a conductive member (15) having a thickness different from that of the substrate (10) and the conductive member (15) shown in FIG. 2 are housed in a case (30) will be described with reference to FIGS. 3 and 4.

[0038] As shown in Fig. 3, when the total thickness of the substrate (10) and the conductive member (15) is smaller than the total thickness of the substrate (10) and the conductive member (15) shown in Fig. 2, the mounting surface (11) of the substrate (10) is brought into contact with a second step surface (42) that is provided on the outer side of the substrate (10) relative to the first step surface (41). In addition, the case (30) and the substrate (10) are bonded together by filling a groove (45) of the second step surface (42) with an adhesive (46).

[0039] In this case, the total thickness, which is the sum of the thickness t1 of the substrate (10) and the thickness t2 of the conductive member (15), is equal to the distance from the reference end face (43) to the second step face (42). In the example shown in FIG. 3, the thickness t1 of the substrate (10) is 300 μm. The thickness t2 of the conductive member (15) is 300 μm. In this case, the distance from the reference end face (43) to the second step face (42) may be set to 600 μm.

[0040] As shown in Fig. 4, when the total thickness of the substrate (10) and the conductive member (15) is greater than the total thickness of the substrate (10) and the conductive member (15) shown in Fig. 2, the mounting surface (11) of the substrate (10) is brought into contact with a second step surface (42) that is provided on the substrate (10) more inward than the first step surface (41). In addition, the case (30) and the substrate (10) are bonded together by filling a groove (45) of the second step surface (42) with an adhesive (46).

[0041] In this case, the total thickness, which is the sum of the thickness t1 of the substrate (10) and the thickness t2 of the conductive member (15), is equal to the distance from the reference end face (43) to the second step face (42). In the example shown in FIG. 4, the thickness t1 of the substrate (10) is 100 μm. The thickness t2 of the conductive member (15) is 2000 μm. In this case, the distance from the reference end face (43) to the second step face (42) may be set to 2100 μm.

[0042] -Effects of the embodiment- According to the features of the present embodiment, if a case (30) of one specification having a first step surface (41) and a second step surface (42) is produced, a semiconductor module can be assembled for a plurality of substrates (10) having different thicknesses, for example, by abutting the mounting surface (11) of the substrate (10) against either the first step surface (41) or the second step surface (42).

[0043] According to the feature of this embodiment, by filling the groove portion (45) with adhesive (46) to bond the case (30) and the substrate (10), it is possible to prevent the adhesive (46) from spilling out from between the mounting surface (11) of the substrate (10) and the first step surface (41) or the second step surface (42).

[0044] According to the feature of this embodiment, when the case (30) is fixed to, for example, the heat sink (20) by screws, it is possible to suppress the application of stress to the substrate (10).

[0045] According to the features of this embodiment, even when the mounting surface (11) of the substrate (10) is abutted against either the first step surface (41) or the second step surface (42), interference of the component (14) with the opposing portion (31) of the case (30) can be suppressed.

[0046] According to the feature of this embodiment, the peripheral edge of the substrate (10) is pressed by the first step surface (41) or the second step surface (42), thereby making it possible to prevent the substrate (10) from tilting.

[0047] Other Embodiments In the above embodiment, the configuration has been described in which the first step surface (41) and the second step surface (42) are provided with the groove portions (45) extending along the circumferential direction of the peripheral wall portion (32). However, for example, the groove portions (45) may be absent, or the groove portions (45) may be provided along the entire circumference, or may be provided partially at multiple locations along the circumferential direction.

[0048] Here, if the grooves (45) are provided along the entire periphery, it is easier to fix the substrate (10). Also, if the grooves (45) are provided partially at a plurality of locations, the amount of adhesive (46) used can be reduced.

[0049] In the above embodiment, a configuration has been described in which the first step surface (41) and the second step surface (42) extend along the circumferential direction of the peripheral wall portion (32). However, the first step surface (41) and the second step surface (42) may be provided along the entire circumference, or may be provided at multiple locations along the circumferential direction.

[0050] Here, if the first step surface (41) and the second step surface (42) are provided along the entire periphery, the tilt of the substrate (10) can be further reduced. Also, if the first step surface (41) and the second step surface (42) are provided partially at a plurality of locations, the tilt of the substrate (10) can be minimized and the amount of material for the peripheral wall portion (32) can be reduced.

[0051] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of those terms.

[0052] As described above, the present disclosure is useful for semiconductor modules.

[0053] REFERENCE SIGNS LIST 1 semiconductor module 10 substrate 11 mounting surface 14 connection wiring (component) 15 conductive member 30 case 31 opposing portion 32 peripheral wall portion 41 first step surface 42 second step surface 43 reference end surface 45 groove portion

Claims

1. A semiconductor module comprising a substrate (10) and a case (30) covering a mounting surface (11) of the substrate (10), wherein the case (30) has a facing portion (31) facing the mounting surface (11) of the substrate (10) and a peripheral wall portion (32) extending toward the substrate (10) along the periphery of the facing portion (31), and the inner surface of the peripheral wall portion (32) is provided with a first step surface (41) abutting against the mounting surface (11) of the substrate (10), and a second step surface (42) extending parallel to the first step surface (41) at least on one of the outer side and inner side of the substrate (10) relative to the first step surface (41); When the second step surface (42) is provided further outward from the substrate (10) than the first step surface (41), the distance from a reference end surface (43) of the peripheral wall portion (32) on the opposite side from the opposing portion (31) to the second step surface (42) is shorter than the distance from the reference end surface (43) to the first step surface (41); and when the second step surface (42) is provided further inward from the substrate (10) than the first step surface (41), the distance from the reference end surface (43) to the second step surface (42) is longer than the distance from the reference end surface (43) to the first step surface (41).

2. The semiconductor module according to claim 1, wherein the first step surface (41) and the second step surface (42) are provided with grooves (45) extending in the circumferential direction of the peripheral wall portion (32).

3. A semiconductor module according to claim 1 or 2, wherein a plate-shaped conductive member (15) is provided on the surface of the substrate (10) opposite to the mounting surface (11), and the reference end surface (43) and the surface of the conductive member (15) opposite to the substrate (10) are arranged on the same plane.

4. A semiconductor module according to any one of claims 1 to 3, wherein the distance h from a point of the component (14) mounted on the substrate (10) closest to the opposing portion (31) to the mounting surface (11) of the substrate (10), the distance H from the reference end face (43) to the opposing portion (31), the distance D1 from the reference end face (43) to the first step surface (41), and the distance D2 from the reference end face (43) to the second step surface (42) satisfy the following conditions: D1<H-h, D2<H-h.

5. A semiconductor module according to any one of claims 1 to 4, wherein the first step surface (41) and the second step surface (42) extend along the circumferential direction of the peripheral wall portion (32).

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