semiconductor modules

Abstract

An insulating substrate (2) is provided on a base plate (1). Semiconductor elements (6 to 9) are provided on the insulating substrate (2). A housing (10) is configured to surround the insulating substrate (2) and the semiconductor elements (6 to 9), and is bonded to the base plate (1) via an adhesive (11). A packaging material (22) packages the insulating substrate (2) and the semiconductor elements (6 to 9) inside the housing (10). A groove (23) is provided on the lower surface of the housing (10) opposite to the outer periphery of the upper surface of the base plate (1). The bottom surface of the groove (23) has a protrusion (24) protruding toward the base plate (1). The protrusion (24) has a vertex (25) and slopes (26, 27) provided on the inner side and the outer side of the housing (10) respectively, sandwiching the vertex (25). The adhesive (11) contacts the vertex (25), and the adhesive (11) is accommodated inside the groove (23).

Description

Technical Field

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

[0002] In the case of semiconductor modules having power semiconductor elements such as MOSFET (Metal Oxide Semiconductor Field Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), and diodes, an adhesive is usually used to join the housing and the base plate. In the case of a module that adopts a potting resin packaging structure, an interface between the adhesive and the packaging material is generated on the inner side of the housing. Depending on the materials of the adhesive and the packaging resin, since their bonding strength is weak, peeling easily occurs at the interface due to thermal cycle stress. Therefore, there is a problem of reduced thermal cycle resistance and impaired reliability. In order to solve this problem, a structure with a bevel on the housing is proposed, which makes it difficult for the adhesive to penetrate into the inner side of the housing (for example, refer to Patent Document 1).

[0003] Patent Document 1: Japanese Patent No. 6399272 Summary of the Invention

[0004] However, with regard to existing structures, if the adhesive application position fluctuates and the adhesive is located inside the housing, the adhesive may invade the inside of the housing after bonding. Additionally, if the adhesive is located outside the housing, the housing and the base plate may not be fully bonded.

[0005] The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a semiconductor module capable of improving thermal cycle resistance and increasing a margin for fluctuations in adhesive application positions.

[0006] The semiconductor module according to the present invention is characterized in that it comprises: a base plate; an insulating substrate, which is arranged on the base plate; a semiconductor element, which is arranged on the insulating substrate; a shell, which is configured to surround the insulating substrate and the semiconductor element and is bonded to the base plate by an adhesive; and a packaging material, which packages the insulating substrate and the semiconductor element inside the shell, and a groove is provided on the lower surface of the shell opposite to the outer periphery of the upper surface of the base plate, the bottom surface of the groove has a protrusion protruding toward the base plate, the protrusion has a vertex and slopes respectively provided at the inner side and the outer side of the shell with the vertex clamped, the adhesive is in contact with the vertex, and the adhesive is accommodated inside the groove.

[0007] Effects of the Invention

[0008] In this embodiment, when the shell and the base plate are joined by the adhesive, the adhesive contacts the top of the protrusion. The adhesive is squeezed and deformed and spreads along the slope of the protrusion. Thus, a sufficient bonding area can be ensured. Moreover, the shell and the base plate can be joined regardless of the thickness of the adhesive. Furthermore, the margin can be increased for fluctuations in the application position of the adhesive. In addition, the squeezed and deformed adhesive escapes to the remaining space of the groove, so the adhesive is contained inside the groove and does not invade the inner side of the shell. Therefore, the interface between the adhesive and the packaging material can be eliminated or reduced, and the thermal cycle resistance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a plan view showing the semiconductor module according to the first embodiment.

[0010] Figure 2 This is a cross-sectional view showing the semiconductor module according to the first embodiment.

[0011] Figure 3 This is an enlarged cross-sectional view of a joint between a case and a base plate of the semiconductor module according to the first embodiment.

[0012] Figure 4 It is a bottom view showing the housing according to the first embodiment.

[0013] Figure 5 It is a bottom view showing a first modification of the housing according to the first embodiment.

[0014] Figure 6 It is a bottom view showing a second modification of the housing according to the first embodiment.

[0015] Figure 7 It is a cross-sectional view showing a step of bonding the housing and the base plate of the semiconductor module according to the first embodiment.

[0016] Figure 8 It is a cross-sectional view showing a step of bonding the housing and the base plate of the semiconductor module according to the first embodiment.

[0017] Figure 9 It is a cross-sectional view showing a step of bonding the housing and the base plate of the semiconductor module according to the first embodiment.

[0018] Figure 10 It is a cross-sectional view showing the relationship between the groove and the adhesive application position in Embodiment 1 and the comparative example.

[0019] Figure 11 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a second embodiment.

[0020] Figure 12This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a third embodiment.

[0021] Figure 13 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a fourth embodiment.

[0022] Figure 14 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a fifth embodiment.

[0023] Figure 15 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a sixth embodiment.

[0024] Figure 16 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a seventh embodiment.

[0025] Figure 17 It is a cross-sectional view showing a first modification of the seventh embodiment.

[0026] Figure 18 This is a cross-sectional view showing a second modification of the seventh embodiment.

[0027] Figure 19 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to an eighth embodiment.

[0028] Figure 20 It is a cross-sectional view showing a first modification of the eighth embodiment.

[0029] Figure 21 It is a cross-sectional view showing a second modification of the eighth embodiment.

[0030] Figure 22 It is a cross-sectional view showing a third modification of the eighth embodiment.

[0031] Figure 23 It is a cross-sectional view showing a semiconductor module according to a ninth embodiment.

[0032] Figure 24 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a ninth embodiment.

[0033] Figure 25 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a tenth embodiment.

[0034] Figure 26 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a tenth embodiment.

[0035] Figure 27 This is a cross-sectional view showing a first modification of the tenth embodiment.

[0036] Figure 28 This is a cross-sectional view showing a first modification of the tenth embodiment.

[0037] Figure 29 This is a cross-sectional view showing a second modification of the tenth embodiment. DETAILED DESCRIPTION

[0038] The semiconductor module according to the embodiment will be described with reference to the accompanying drawings. The same reference numerals are used for the same or corresponding components, and redundant description may be omitted.

[0039] Implementation Method 1

[0040] Figure 1 This is a plan view showing the semiconductor module according to the first embodiment. Figure 2 This is a cross-sectional view of a semiconductor module according to Embodiment 1. Base plate 1 is made of copper or aluminum. An insulating substrate 2 is disposed on base plate 1. Insulating substrate 2 is made of a ceramic material such as silicon nitride, aluminum nitride, aluminum oxide, or Zr-containing aluminum oxide. Silicon nitride and aluminum nitride are particularly preferred from the perspective of thermal conductivity, while silicon nitride is preferred from the perspective of material strength. Epoxy resin, etc., can also be used for insulating substrate 2.

[0041] A metal layer 3 is provided on the lower surface of an insulating substrate 2. Metal layer 3 is bonded to base plate 1 using solder or the like. Conductive patterns 4 and 5 are provided on insulating substrate 2. Metal layer 3 and conductive patterns 4 and 5 are made of aluminum, an aluminum alloy, copper, or a copper alloy. Copper is particularly preferred due to its excellent electrical and thermal conductivity.

[0042] Semiconductor elements 6 and 7 are provided on conductive pattern 4. The lower surface electrodes of semiconductor elements 6 and 7 are bonded to conductive pattern 4 via solder or the like. Semiconductor elements 8 and 9 are provided on conductive pattern 5. The lower surface electrodes of semiconductor elements 8 and 9 are bonded to conductive pattern 5 via solder or the like. Semiconductor elements 6 and 9 are switching elements such as MOSFETs and IGBTs that control large currents. Semiconductor elements 7 and 8 are freewheeling diodes.

[0043] The housing 10, which is in the shape of a square frame, is arranged on the base plate 1 so as to surround the insulating substrate 2 and the semiconductor elements 6 to 9, and is bonded to the outer periphery of the upper surface of the base plate 1 by an adhesive 11. The housing 10 is required to maintain its insulation properties without thermal deformation within the operating temperature range of the semiconductor module. Therefore, the material of the housing 10 is a resin with a high softening point, such as PPS (Poly Phenylene Sulfide) resin or PBT (Poly butylene terephthalate) resin. The material of the adhesive 11 is, for example, silicone resin, epoxy resin, etc. For example, the adhesive 11 is applied to the outer periphery of the upper surface of the base plate 1, and after the housing 10 and the base plate 1 are bonded, the adhesive 11 is thermally cured to achieve bonding.

[0044] Housing 10 is provided with main terminals 12-14 and control terminals 15 and 16. Bonding wire 17 connects the upper surface electrodes of semiconductor elements 6 and 7 to main terminal 12. Bonding wire 18 connects conductive pattern 5 to main terminal 13. Bonding wire 19 connects conductive pattern 4, the upper surface electrodes of semiconductor elements 8 and 9, and main terminal 14. Bonding wire 20 connects the control electrode of semiconductor element 6 to control terminal 15. Bonding wire 21 connects the control electrode of semiconductor element 9 to control terminal 16.

[0045] The encapsulating material 22 encapsulates the insulating substrate 2, semiconductor elements 6 to 9, and bonding wires 17 to 21 within the housing 10. The encapsulating material 22 is sealed by the base plate 1 and the housing 10. The encapsulating material 22 is made of epoxy resin, phenol resin, polyimide resin, or the like, and contains inorganic fillers with excellent thermal conductivity, such as alumina and silica. Furthermore, even when the adhesive 11 and the encapsulating material 22 are made of the same material, the additives differ depending on the application, and therefore do not have the same linear expansion coefficient. Therefore, thermal stress caused by the difference in linear expansion coefficient may occur due to thermal cycling.

[0046] Figure 3This is an enlarged cross-sectional view of the joint between the housing and base plate of the semiconductor module according to Embodiment 1. A groove 23 is provided on the lower surface of the housing 10, facing the outer periphery of the upper surface of the base plate 1. The bottom surface of the groove 23 has a protrusion 24 that projects toward the base plate 1. The protrusion 24 has a vertex 25 and slopes 26 and 27, respectively, located further inward and further outward of the housing 10, sandwiching the vertex 25. The adhesive 11 contacts the vertex 25 and is contained within the groove 23. The width of the groove 23 is, for example, greater than or equal to 2.6 mm and is set based on the applied width and positional fluctuations of the adhesive 11. The depth of the groove 23 is, for example, greater than or equal to 0.4 mm and is set to the assumed height of the adhesive 11 plus greater than or equal to 0.1 mm. The distance between the vertex 25 of the protrusion 24 and the base plate 1 is, for example, greater than or equal to 0 mm and less than or equal to 0.3 mm. At the lower limit of 0 mm, the apex 25 contacts the base plate 1. The upper limit of 0.3 mm is lower than the assumed height of the adhesive 11. The closer to the lower limit, the easier it is for the apex 25 to contact the adhesive 11.

[0047] The lower surface of the housing 10 has a flat surface 28, located closer to the inside of the housing 10 than the groove 23. The height of the protrusion 24 is not lower than the height of the flat surface 28, and is less than or equal to the height at which the vertex 25 contacts the base plate 1. Therefore, the flat surface 28 makes surface contact with the outer periphery of the upper surface of the base plate 1. This prevents the adhesive 11 from entering the interior of the housing 10, even if it overflows from the groove 23. Furthermore, it prevents the encapsulating material 22 from flowing outside the housing 10.

[0048] Figure 4 This is a bottom view of the housing according to Embodiment 1. Grooves 23 are provided along the entire circumference of the lower surface of housing 10. While grooves 23 are preferably provided along the entire circumference of the area where adhesive 11 is applied as described above, they may be provided only in a portion as long as reliability is ensured.

[0049] Figure 5 This is a bottom view of a first variation of the housing according to Embodiment 1. A groove 23 having a protrusion 24 is provided in a wide portion of the housing 10. A groove 29 having no protrusion 24 and a rectangular cross-section is provided in a narrow portion of the housing 10. In this manner, grooves 23 may be provided only in locations where a groove structure of sufficient size can be provided.

[0050] Figure 6 This is a bottom view of a second variation of the housing according to Embodiment 1. Housing 10 is typically manufactured by injection molding. Consequently, gate marks from the resin injection path and mold release pin marks from removal from the mold remain in the finished product. Therefore, groove 23 is provided to avoid region 30 of housing 10 where gate marks or mold release pin marks remain.

[0051] Figures 7 to 9 1 is a cross-sectional view showing the process of joining the housing and the base plate of the semiconductor module according to the first embodiment. Figure 7 As shown in FIG. 1 , an adhesive 11 is applied to the outer periphery of the upper surface of the base plate 1. Next, as shown in FIG. Figure 8 As shown, if the housing 10 is attempted to be joined to the base plate 1, the adhesive 11 contacts the apex 25 of the protrusion 24. Figure 9 As shown, if the housing 10 is further lowered, the adhesive 11 is squeezed and deformed, spreading along the slopes 26 and 27 of the protrusion 24. This ensures a sufficient bonding area. Furthermore, regardless of the thickness of the adhesive 11, the housing 10 and the base plate 1 can be bonded.

[0052] Figure 10 This is a cross-sectional view showing the relationship between the groove and the adhesive application position in Embodiment 1 and the comparative example. While Embodiment 1 includes slopes 26 and 27 on either side of the apex 25 of protrusion 24, the comparative example only has a single slope 31. Therefore, in the comparative example, if adhesive 11 is applied further inward of housing 10 than apex 25, bonding will not occur. Consequently, the margin W2 for fluctuations in the application position of adhesive 11 is small.

[0053] In contrast, in the present embodiment, when the housing 10 and the base plate 1 are joined by the adhesive 11, the adhesive 11 contacts the apex 25 of the protrusion 24 and is squeezed and deformed, and spreads along the slopes 26 and 27 on both sides of the protrusion 24. Therefore, even if the adhesive 11 is applied to the inner side or the outer side of the housing 10 relative to the apex 25, joining is possible. Therefore, the margin W1 can be increased to account for fluctuations in the application position of the adhesive 11. Thus, assembly failures can be reduced. In addition, the squeezed and deformed adhesive 11 escapes to the remaining space of the groove 23, so the adhesive 11 is contained inside the groove 23 and does not invade the inner side of the housing 10. Therefore, the interface between the adhesive 11 and the packaging material 22 can be eliminated or reduced, and the thermal cycle resistance can be improved.

[0054] Furthermore, even if the adhesive 11 does not contact the apex 25 of the protrusion 24 due to fluctuations in the application position, if there is a slight deviation, the slopes 26 and 27 can be bonded to the base plate 1 by the adhesive 11. Taking this into account, the margin for fluctuations in the application position of the adhesive 11 can be further increased.

[0055] Furthermore, adhesive 11 contacts not the flat surface of housing 10 but the apex 25 of projection 24 and its adjacent slopes 26 and 27. Therefore, adhesive 11 is less likely to be squeezed and deformed, and thus less likely to overflow from the joint.

[0056] Furthermore, in the case of a typical rectangular groove, if the height of adhesive 11 is lower than the groove depth, the housing 10 and base plate 1 cannot be bonded together using adhesive 11. Increasing the amount of adhesive 11 to increase the height of adhesive 11 increases the risk of adhesive 11 overflowing. In contrast, in this embodiment, the apex 25 of protrusion 24 provided on the bottom surface of groove 23 contacts adhesive 11, enabling bonding even with a small amount of adhesive 11 and a low height. Consequently, there is a margin for fluctuations in the height of adhesive 11.

[0057] Furthermore, a conductive frame can be used instead of bonding wires 17-21. This increases the allowable current capacity of the semiconductor module. Furthermore, although the semiconductor module is assumed to be used with the base plate connected to the cooling fins via thermal grease, columnar fins can be formed on the base plate 1 instead of the cooling fins and thermal grease. This can eliminate assembly steps and improve thermal resistance.

[0058] Implementation Method 2

[0059] Figure 11 This is an enlarged cross-sectional view of the joint between the housing and base plate of the semiconductor module according to Embodiment 2. In Embodiment 1, the protrusion 24 provided on the bottom surface of the groove 23 of the housing 10 has a triangular cross-section. However, in this embodiment, the protrusion 24 has a curved shape with a predetermined curvature. This reduces the risk of cracking or damage to the housing 10 and the housing mold, and improves the durability of the components. Other structures and effects are the same as those of Embodiment 1.

[0060] Implementation 3

[0061] Figure 12 This is an enlarged cross-sectional view of the joint between the housing and the base plate of the semiconductor module involved in embodiment 3. Surface roughening processing 32 is applied to the entire surface or a portion of the inner surface of the groove 23 of the housing 10 and the entire surface or a portion of the area of ​​the base plate 1 where the adhesive 11 is applied. Fine concave and convex shapes are formed on the surface by surface roughening processing 32. The height difference of the concave and convex shapes is, for example, greater than or equal to 0.01 mm. As a result, the flow length of the adhesive 11 is lengthened, and the flow of the adhesive 11 is suppressed. Therefore, it is more difficult for the adhesive 11 to invade the inner side of the housing 10. Therefore, the interface between the adhesive 11 and the packaging material 22 can be eliminated or further reduced. Other structures and effects are the same as those in embodiment 1.

[0062] Implementation 4

[0063] Figure 13 This is an enlarged cross-sectional view of the joint between the housing and base plate of a semiconductor module according to Embodiment 4. A grid-shaped sheet 33 is attached to the entire surface or a portion of the area where adhesive 11 is applied to base plate 1. This achieves the same effects as in Embodiment 3. Other structures and effects are the same as in Embodiment 1.

[0064] Implementation 5

[0065] Figure 14 This is an enlarged cross-sectional view of the joint between the housing and base plate of the semiconductor module according to Embodiment 5. A bonding wire 34 is provided on the outer periphery of the upper surface of the base plate 1, facing the groove 23, in an area further inward of the housing 10 than the area where the adhesive 11 is applied. This achieves the same effects as in Embodiment 3. The remaining structure and effects are the same as in Embodiment 1. Alternatively, a bonding wire 34 may be provided in an area further outward of the housing 10 than the area where the adhesive 11 is applied. This prevents the adhesive 11 from overflowing outside the housing 10.

[0066] Implementation Method 6

[0067] Figure 15 This is an enlarged cross-sectional view of the joint between the housing and the base plate of the semiconductor module according to Embodiment 6. A recess 35 is provided in the base plate 1, opposite the groove 23 of the housing 10. Adhesive 11 is applied to the bottom surface of the recess 35. The width of the recess 35 is larger than the width of the area where the adhesive 11 is applied, but smaller than the width of the groove 23. The height of the protrusion 24 is set to a height at which the apex 25 contacts the adhesive 11 in the recess 35. The depth of the recess 35 is, for example, greater than or equal to 0.1 mm, but is set to be less than or equal to 4 / 5 of the thickness of the base plate 1 to prevent penetration of the base plate 1.

[0068] The recess 35 increases the space for accommodating the adhesive 11. This makes it more difficult for the adhesive 11 to penetrate the inner side of the housing 10. Consequently, the interface between the adhesive 11 and the packaging material 22 can be eliminated or further reduced. Other structures and effects are the same as those of the first embodiment.

[0069] Implementation 7

[0070] Figure 16This is an enlarged cross-sectional view of the joint between the housing and base plate of a semiconductor module according to Embodiment 7. A recess 36 is provided on the outer periphery of the upper surface of base plate 1 in the area facing the lower surface of housing 10. Recess 36 is provided in an area further inward of housing 10 than the area where adhesive 11 is applied. The depth of recess 36 is, for example, greater than or equal to 1 / 10 of the thickness of base plate 1, but is preferably less than or equal to 4 / 5 of the thickness of base plate 1 to prevent penetration of base plate 1.

[0071] Adhesive 11, squeezed and deformed by base plate 1 and housing 10, is contained in recess 36. Therefore, adhesive 11 is less likely to penetrate the interior of housing 10. Consequently, the interface between adhesive 11 and packaging material 22 can be eliminated or further reduced. Other structures and effects are the same as those of embodiment 1.

[0072] Figure 17 This is a cross-sectional view showing a first variation of embodiment 7. As shown in the first variation, a plurality of continuous recesses 36 may be provided. Thus, even if the adhesive 11 spreads beyond the first nearest recess 36, it is contained by the second and subsequent recesses 36. Consequently, the adhesive 11 is less likely to intrude into the interior of the housing 10.

[0073] Figure 18 This is a cross-sectional view showing a second variation of Embodiment 7. As shown in the second variation, a plurality of recesses 36 may be provided in areas further inside and outside the housing 10 than the area where the adhesive 11 is applied. This prevents the adhesive 11 from overflowing outside the housing 10.

[0074] Implementation 8

[0075] Figure 19 This is an enlarged cross-sectional view of the joint between the housing and the base plate of the semiconductor module involved in embodiment 8. In an area closer to the inner side of the housing 10 than the groove 23, the outer peripheral portion of the upper surface of the base plate 1 contacts the lower surface of the housing 10. In this contact area, a recess 38 is provided on the outer peripheral portion of the upper surface of the base plate 1, and a protrusion 37 is provided on the lower surface of the housing 10. The recess 38 has a size to accommodate the protrusion 37. When the housing 10 is bonded to the base plate 1 by the adhesive 11, the protrusion 37 and the recess 38 are fitted together. The depth of the recess 38 and the height of the protrusion 37 are, for example, greater than or equal to 1 / 10 of the thickness of the base plate 1. In order to prevent the base plate 1 from penetrating, the depth of the recess 38 is set to be less than or equal to 4 / 5 of the thickness of the base plate 1.

[0076] If, due to assembly fluctuations, the adhesive 11 is positioned further inward of the housing 10 than the specified position or a large amount of adhesive 11 is applied, the adhesive 11 may spread and reach the contact area between the base plate 1 surface and the housing 10, causing the adhesive 11 to infiltrate the interior of the housing 10 due to capillary action. In contrast, in this embodiment, the provision of the protrusions 37 and recesses 38 increases the flow length of the adhesive 11, thereby suppressing the intrusion of the adhesive 11 into the interior of the housing 10. Consequently, a greater margin can be provided for fluctuations in the application of the adhesive 11.

[0077] Figure 20 is a cross-sectional view showing a modification example 1 of the eighth embodiment. Figure 19 On the contrary, the convex portion 37 is provided on the outer peripheral portion of the upper surface of the base plate 1, and the concave portion 38 is provided on the lower surface of the housing 10. Even in this case, the same effects as those of the eighth embodiment can be obtained.

[0078] Figure 21 This is a cross-sectional view showing a second variation of Embodiment 8. In this variation, multiple protrusions 37 and recesses 38 are provided. This makes it even more difficult for adhesive 11 to penetrate the interior of housing 10. Furthermore, protrusions 37 and recesses 38 are also provided in the contact area between the outer periphery of the upper surface of base plate 1 and the lower surface of housing 10, further outside of groove 23. This prevents adhesive 11 from overflowing outside housing 10.

[0079] Figure 22 This is a cross-sectional view showing a third variation of the eighth embodiment. In this variation, unlike the second variation, a plurality of protrusions 37 are provided on the outer periphery of the upper surface of the base plate 1, and a plurality of recesses 38 are provided on the lower surface of the housing 10. Even in this case, the same effects as those of the second variation can be achieved.

[0080] Implementation Method 9

[0081] Figure 23 It is a cross-sectional view showing a semiconductor module according to a ninth embodiment. Figure 24 This is an enlarged cross-sectional view of the joint between the housing and base plate of a semiconductor module according to Embodiment 9. A recess 39 is provided on the upper surface of base plate 1, further inward than the outer periphery of the upper surface where it joins housing 10. Insulating substrate 2 and semiconductor elements 6-9 are positioned within recess 39. This allows for a smaller package size, improved thermal resistance, and reduced warpage on the module's rear surface.

[0082] A protrusion 40 is provided on the lower surface of the housing 10, further inward of the housing 10 than the groove 23. The protrusion 40 projects downward from the portion of the lower surface of the housing 10 further outward than the groove 23 and is inserted into the recess 39. The adhesive 11, which is squeezed and deformed and expanded by the joining of the base plate 1 and the housing 10, flows toward the inside of the housing 10 but is prevented by the protrusion 40. This makes it difficult for the adhesive 11 to penetrate the inside of the housing 10. Consequently, the interface between the adhesive 11 and the packaging material 22 can be eliminated or reduced.

[0083] Implementation 10

[0084] Figure 25 and Figure 26 This is an enlarged cross-sectional view of a joint between a case and a base plate of a semiconductor module according to a tenth embodiment. Figure 25 The state before the housing 10 and the base plate 1 are joined is shown. Figure 26 The following figure shows the joined state. A protrusion 41 is provided on the lower surface of the housing 10. The protrusion 41 is provided further inward of the housing 10 than the groove 23. The height of the protrusion 41 is, for example, greater than or equal to 1 / 10 of the thickness of the base plate 1 and less than or equal to 1 / 2 of the thickness of the base plate 1. The base plate 1 is made of, for example, aluminum, which has a lower strength than the protrusion 41.

[0085] When the housing 10 is bonded to the base plate 1, the outer periphery of the upper surface of the base plate 1 contacts the protrusions 41 and bends due to surface pressure, bonding the outer periphery of the upper surface of the base plate 1 to the lower surface of the housing 10. This allows for a gap-free or gap-less bond, making it more difficult for the adhesive 11 to penetrate the interior of the housing 10. Consequently, the interface between the adhesive 11 and the sealing material 22 can be eliminated or reduced.

[0086] Figure 27 and Figure 28 This is a cross-sectional view showing a first modification of the tenth embodiment. Figure 27 The state before the housing 10 and the base plate 1 are joined is shown. Figure 28 The following figure shows the state after bonding. Base plate 1 is made of a high-strength material such as copper and is provided with protrusions 41. In this case, the lower surface of housing 10 contacts protrusions 41, bending due to surface pressure, and base plate 1 and housing 10 are bonded. Even in this case, the same effects as those of embodiment 10 can be achieved.

[0087] Figure 29 This is a cross-sectional view showing a second variation of Embodiment 10. The protrusion 41 is a metal 42 embedded in the lower surface of the housing 10. The metal 42 has a higher strength than the base plate 1. This facilitates bending of the base plate 1 and facilitates joining the base plate 1 to the housing 10. Alternatively, the protrusion 41 may be provided by embedding the metal 42 in the outer periphery of the upper surface of the base plate 1.

[0088] Furthermore, semiconductor elements 6 to 9 are not limited to being formed from silicon, but can also be formed from wide-bandgap semiconductors having a larger bandgap than silicon. Examples of wide-bandgap semiconductors include silicon carbide, gallium nitride-based materials, or diamond. Power semiconductor elements formed from such wide-bandgap semiconductors have high voltage resistance and allowable current density, and thus can be miniaturized. By using these miniaturized elements, the semiconductor module incorporating them can also be miniaturized. Furthermore, due to the high heat resistance of the elements, the heat sink fins can be miniaturized, and the water-cooled unit can be converted to air-cooled, thereby further miniaturizing the semiconductor module.

[0089] Description of the label

[0090] 1 Base plate, 2 Insulating substrate, 6-9 Semiconductor element, 10 Housing, 11 Adhesive, 22 Packaging material, 23 Groove, 24 Protrusion, 25 Vertex, 26, 27 Slope, 32 Surface roughening, 33 Grid-shaped sheet, 34 Bonding wire, 35, 36, 38, 39 Recess, 37, 40 Protrusion, 41 Bump, 42 Metal.

Claims

1. A semiconductor module, characterized in that: have: base plate; an insulating substrate, which is disposed on the base plate; a semiconductor element disposed on the insulating substrate; a housing configured to surround the insulating substrate and the semiconductor element and bonded to the base plate by an adhesive; as well as a packaging material that packages the insulating substrate and the semiconductor element inside the housing, A groove is provided on the lower surface of the housing opposite to the outer peripheral portion of the upper surface of the base plate. The bottom surface of the groove has a protrusion protruding toward the base plate, The protrusion has a vertex and slopes provided on the inner side and the outer side of the housing respectively, sandwiching the vertex. The apex and the slope surfaces on both sides of the apex form a V-shaped or curved cross-sectional shape having a predetermined curvature. The adhesive is in contact with the apex, and is contained in the groove without completely filling the groove. The adhesive in contact with the apex of the protrusion is squeezed and deformed to spread along the slope surfaces on both sides of the protrusion sandwiching the apex.

2. The semiconductor module according to claim 1, wherein The height of the protrusion is less than or equal to the height at which the apex contacts the base plate.

3. The semiconductor module according to claim 1 or 2, characterized in that The inner surface of the groove of the housing and the region of the base plate to which the adhesive is applied are subjected to surface roughening.

4. The semiconductor module according to claim 1 or 2, characterized in that A grid-shaped sheet is attached to the area of ​​the base plate where the adhesive is applied.

5. The semiconductor module according to claim 1 or 2, characterized in that A bonding wire is provided on an outer peripheral portion of an upper surface of the base plate facing the groove.

6. The semiconductor module according to claim 5, characterized in that The bonding wire is provided on an inner side of the housing than a region where the adhesive is applied.

7. The semiconductor module according to claim 1 or 2, characterized in that A recess is provided on the base plate. The adhesive is applied to the recessed portion.

8. The semiconductor module according to claim 1 or 2, characterized in that A recess is provided on an outer peripheral portion of an upper surface of the base plate that faces the lower surface of the housing.

9. The semiconductor module according to claim 8, characterized in that The recessed portion is provided on an inner side of the housing than a region where the adhesive is applied.

10. The semiconductor module according to claim 8, wherein A plurality of the recesses are provided.

11. The semiconductor module according to claim 1 or 2, characterized in that A convex portion is provided on one of an outer peripheral portion of an upper surface of the base plate and a lower surface of the housing, and a concave portion is provided on the other, and the convex portion is fitted into the concave portion.

12. The semiconductor module according to claim 11, wherein The convex portion and the concave portion are provided on an inner side of the housing than the groove.

13. The semiconductor module according to claim 11, wherein A plurality of the convex portions and the concave portions are respectively provided.

14. The semiconductor module according to claim 1 or 2, characterized in that A recessed portion is provided on the upper surface of the base plate at an inner side of an outer peripheral portion of the upper surface joined to the housing. The insulating substrate and the semiconductor element are provided in the recess. A convex portion is provided on the lower surface of the housing at a position closer to the inside of the housing than the groove. The convex portion is inserted into the concave portion.

15. A semiconductor module, characterized in that: have: base plate; an insulating substrate, which is disposed on the base plate; a semiconductor element disposed on the insulating substrate; a housing configured to surround the insulating substrate and the semiconductor element and bonded to the base plate by an adhesive; as well as a packaging material that packages the insulating substrate and the semiconductor element inside the housing, A groove is provided on the lower surface of the housing opposite to the outer peripheral portion of the upper surface of the base plate. The bottom surface of the groove has a protrusion protruding toward the base plate, The protrusion has a vertex and slopes provided on the inner side and the outer side of the housing respectively, sandwiching the vertex. The adhesive is in contact with the apex and is contained within the groove. A protrusion is provided on one of the outer peripheral portion of the upper surface of the base plate and the lower surface of the shell, and the other contacts the protrusion and bends due to surface pressure, and the protrusion bites into the other, so that the base plate and the shell are joined. The one of the base plate and the housing has a higher strength than the other.

16. The semiconductor module according to claim 15, characterized in that The protrusion is provided on an inner side of the housing than the groove.

17. The semiconductor module according to claim 15 or 16, characterized in that The protrusion is made of metal and is embedded in one of the outer peripheral portion of the upper surface of the base plate and the lower surface of the housing, and has higher strength than the other.

18. The semiconductor module according to any one of claims 1, 2 and 15, wherein: The semiconductor element is formed of a wide bandgap semiconductor.

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