JP7354605B2 - Semiconductor modules and semiconductor devices - Google Patents

Description

The present invention relates to a semiconductor module and a semiconductor device.

A semiconductor module includes a semiconductor element and a substrate with the semiconductor element mounted on the front surface. The back surface of the substrate is exposed from the semiconductor module. For example, Patent Documents 1 and 2. A semiconductor device has a structure in which a cooler such as a heat sink, a radiation fin, or a water cooling jacket is attached to such a semiconductor module. The cooler is attached to the back surface of the substrate exposed from the semiconductor module via a thermally conductive paste or a thermally conductive sheet.

Japanese Patent Application Publication No. 2000-200865 JP2018-174228A

When such a semiconductor module is attached to a cooler, a large gap is created between the back surface of the substrate and the cooler, which may reduce heat dissipation. This prevents the heat generated during operation of the semiconductor module from being radiated to the cooler, and there is a risk that the semiconductor module may be destroyed due to overheating.

The present invention has been made in view of these points, and it is an object of the present invention to provide a semiconductor module that suppresses the distance between the back surface of the substrate and the cooler, and suppresses deterioration in heat dissipation.

According to one aspect of the present invention, a plurality of semiconductor elements, a plurality of substrates each having the semiconductor elements mounted on a front surface, and a front surface of the plurality of substrates and each of the semiconductor elements are included. and a case having a back surface of the substrate extending from a bottom surface and a fastening portion disposed between the substrate and an outer periphery near both ends so as to sandwich the plurality of substrates in a plan view. , the amount of extension of the edges of the plurality of substrates near the fastening portions on the outer peripheral side of the case from the case bottom surface is such that the amount of extension of the edges of the plurality of substrates adjacent to the plurality of substrates on the case center side from the case bottom surface A semiconductor module having an extension amount smaller than that of the semiconductor module is provided.

According to the disclosed technology, it is possible to suppress a decrease in heat dissipation performance and prevent a decrease in reliability.

FIG. 1 is a perspective view of the semiconductor module according to the first embodiment of the present invention, seen diagonally from above. FIG. 1 is a perspective view of the semiconductor module according to the first embodiment of the present invention, as seen diagonally from below. FIG. 1 is a cross-sectional view of a semiconductor module according to a first embodiment of the present invention. FIG. 2 is a plan view of the inside of the semiconductor module according to the first embodiment of the present invention. FIG. 2 is a bottom view of the semiconductor module according to the first embodiment of the present invention. FIG. 1 is a partial cross-sectional view of a semiconductor module according to a first embodiment of the present invention. FIG. 1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a semiconductor module according to a modification of the first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a semiconductor module according to a modification of the first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a semiconductor module according to a modification of the first embodiment of the present invention. FIG. 3 is a partial cross-sectional view of a semiconductor module according to a modification of the first embodiment of the present invention. FIG. 3 is a cross-sectional view of a semiconductor module according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a semiconductor device according to a second embodiment of the present invention. FIG. 7 is a bottom view of a semiconductor module according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view of a semiconductor module according to a third embodiment of the present invention. FIG. 7 is a bottom view of a semiconductor module according to a fourth embodiment of the present invention. FIG. 7 is a cross-sectional view of a semiconductor module according to a fourth embodiment of the present invention. FIG. 7 is a bottom view of a semiconductor module according to a fifth embodiment of the present invention. FIG. 7 is a cross-sectional view of a semiconductor module according to a fifth embodiment of the present invention. FIG. 3 is a cross-sectional view of a semiconductor module of a comparative example. FIG. 3 is a cross-sectional view of a semiconductor device of a comparative example.

Embodiments of the present invention will be described below. In the description of the drawings below, the same or similar parts are designated by the same or similar symbols. However, it should be noted that the drawings are schematic and the relationship between thickness and planar dimension, the ratio of the thickness of each device and each member, etc. may differ from reality. Therefore, specific thickness and dimensions should be determined with reference to the following explanation. Furthermore, it goes without saying that the drawings include portions with different dimensional relationships and ratios.

In the description of the drawings below, directions may be indicated using the X-axis direction, Y-axis direction, and Z-axis direction. For example, the X-axis direction and the Y-axis direction are directions parallel to the bottom surface of the semiconductor module 10, which will be described later. The Z-axis direction is a direction perpendicular to the bottom surface of the semiconductor module 10, which will be described later. The X-axis direction, Y-axis direction, and Z-axis direction are orthogonal to each other.

In the following description, the positive direction of the Z-axis may be referred to as "up", and the negative direction of the Z-axis may be referred to as "down". "Above" and "below" do not necessarily mean a direction perpendicular to the ground. That is, the "up" and "down" directions are not limited to the direction of gravity. "Top" and "bottom" are merely convenient expressions for specifying relative positional relationships, and do not limit the technical idea of the present invention. For example, if the page is rotated 180 degrees, "top" becomes "bottom" and "bottom" becomes "top".

Further, in the following description, technical matters may be explained using expressions such as front surface, back surface, top surface, and bottom surface. The surface in the positive direction of the Z-axis is sometimes called the front surface or top surface, and the surface in the negative direction of the Z-axis is sometimes called the back surface or bottom surface. Furthermore, in the following description, the term "side surface" means a surface connecting the front surface and the back surface. “Plane view” means viewing from the normal direction of the bottom surface of the semiconductor module 10 (that is, the Z-axis direction). “Cross-sectional view” means viewing from a direction parallel to the bottom surface of the semiconductor module 10 (that is, a direction perpendicular to the Z-axis).

(First embodiment)
Embodiments will be described below with reference to the drawings. The semiconductor module of this embodiment will be explained using FIGS. 1 to 7.

1 and 2 show the external appearance of the semiconductor module 10, and FIG. 1 shows the semiconductor module 10 viewed diagonally from above, showing the top and side surfaces of the semiconductor module 10. FIG. 2 shows the semiconductor module 10 viewed diagonally from below, showing the bottom and side surfaces of the semiconductor module 10. As shown in FIGS. 1 and 2, the semiconductor module 10 has a generally rectangular parallelepiped shape. The outer shape of the semiconductor module 10 is mostly formed by the case 11. On the upper surface of the semiconductor module 10, the tips of external connection terminals 13 extend from the case 11. On the bottom surface of the semiconductor module 10, the back surface of the laminated substrate 20 extends from the case 11. The structure of the bottom surface of the semiconductor module 10 will be described in detail later.

The semiconductor module 10 includes fastening portions 14 near both ends in the longitudinal direction (X-axis direction). The fastening portion 14 may be a hole that penetrates the semiconductor module 10 in the vertical direction (Z-axis direction). The fastening portion 14 is a portion where a fastening member made of a screw or the like for fastening the bottom surface of the semiconductor module 10 to a cooler or the like to be described later is arranged. A total of two fastening portions 14 are provided near both ends of the case 11 in the longitudinal direction of the semiconductor module 10 . The structure, position, and number of fastening portions 14 are not limited to these. For example, the fastening portion 14 may be a recess into which a clamp is attached as a fastening member. For example, the fastening parts 14 may be located at each of the four corners of a rectangle when the semiconductor module 10 is viewed from above, and there may be a total of four fastening parts 14. The fastening portion 14 is preferably formed on the outer edge of the semiconductor module 10 on the outside of the laminated substrate 20 described later in plan view. By being formed on the outer edge of the semiconductor module 10, the fastening part 14 can securely fix a cooler etc., and by being located outside the laminated substrate 20, it can suppress excessive stress on the laminated substrate 20. Damage to the laminated substrate 20 can be suppressed.

FIG. 3 shows an AA cross section of the semiconductor module in FIG. FIG. 4 shows the inside of the semiconductor module 10 of FIG. 1 viewed from above. Note that in FIGS. 3 and 4, main parts are schematically shown, and external connection terminals and internal wiring are not shown.

As shown in FIGS. 3 and 4, the semiconductor module 10 includes a semiconductor element 24, a laminated substrate 20, and a case 11. The case 11 contains the semiconductor element 24, the front surface (the surface located on the positive side in the Z-axis direction) of the laminated substrate 20, and part of the side surfaces (XZ plane and YZ plane) of the laminated substrate 20, and the semiconductor module. Construct 10 external shapes. The case 11 may have a molded structure that also serves to seal the front surfaces of the semiconductor element 24 and the laminated substrate 20. Such a case 11 is formed, for example, by molding using a thermosetting resin. Examples of such resins include epoxy resins mixed with inorganic fillers.

Further, for example, the case 11 may include a frame-shaped or box-shaped casing portion including a storage area therein, and a sealing portion embedded in the storage area. The housing section includes the semiconductor element 24 and the front surface of the laminated substrate 20 in the storage area. The housing portion of the case 11 is formed, for example, by injection molding using thermoplastic resin. Examples of such thermoplastic resins include polyphenylene sulfide (PPS), polybutylene terephthalate (PBT) resin, polybutylene succinate (PBS) resin, polyamide (PA) resin, and acrylonitrile butadiene styrene (ABS) resin. The sealing portion of the case 11 is made of, for example, epoxy resin mixed with an inorganic filler, silicone gel, or the like.

The semiconductor element 24 is bonded to the front surface of the conductive plate 21 of the laminated substrate 20 via a bonding member 25 such as solder. The semiconductor element 24 has its back surface electrically connected to the conductive plate 21, and its front surface connected to another conductive plate 21 (not shown) or external connection terminals through a wiring member (not shown) such as a conductive wire. It is electrically connected to 13. 3 and 4, wiring members such as external connection terminals and conductive wires inside the semiconductor module are omitted. The semiconductor element 24 includes, for example, a switching element such as an IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Further, the semiconductor element 24 includes a diode such as an SBD (Schottky Barrier Diode) or an FWD (Free Wheeling Diode), if necessary. Furthermore, the semiconductor element 24 may include an RC (Reverse Conducting)-IGBT, which is a single element that is a combination of an IGBT and a FWD. The semiconductor element 24 may be a silicon semiconductor or a silicon carbide semiconductor. Note that, in FIGS. 3 and 4, an example in which each stacked substrate includes four semiconductor elements 24 is described. The present invention is not limited to this case, and the semiconductor elements 24 may be arranged in different numbers or positions on each laminated substrate.

Two laminated substrates 20 are arranged side by side in the longitudinal direction (X-axis direction) of the rectangular semiconductor module 10 in plan view. The laminated substrate 20 is surrounded by the case 11 in plan view. The case 11 includes a fastening portion 14 between the short side of each case 11 and the laminated substrate 20, and the laminated substrate 20 is provided at a position sandwiched between the pair of fastening portions 14. The arrangement of the fastening portion 14 of the case 11 and the laminated substrate 20 may be symmetrical in the long side direction (X-axis).

The laminated board 20 includes an insulating plate 22, a conductive plate 21 formed on the front surface (Z-axis positive side) of the insulating plate 22, and a conductive plate 21 formed on the back surface (Z-axis negative side) of the insulating plate 22. It has a heat dissipation plate 23. The conductive plate 21, the insulating plate 22, and the heat sink 23 are generally plate-shaped, and the laminated substrate 20 is also plate-shaped. In plan view, the outer shape of the insulating plate 22 is larger than the outer shape of the heat sink 23 and the outer shape of the conductive plate 21. Therefore, the edge of the insulating plate 22 protrudes from the heat sink 23 and the conductive plate 21. The front surface (the surface on the positive side of the Z-axis) of the heat sink 23 is joined to the insulating plate 22 . The back surface (Z-axis negative side surface) of the conductive plate 21 is joined to the insulating plate 22, and the front surface (Z-axis positive side surface) of the conductive plate 21 is connected to the semiconductor element 24 via a bonding member 25 such as solder. is placed. The insulating plate 22, the conductive plate 21, and the semiconductor element 24 are embedded in the case 11. On the bottom surface of the semiconductor module 10, the back surface of the heat sink 23 extends from the case 11. The heat sink 23 is embedded halfway in the case 11 in the thickness direction, and a portion of the side surfaces (XZ plane and YZ plane) and the bottom surface extend from the case 11 . Therefore, the bottom surface of the semiconductor module 10 has a step between the heat sink 23 and the case 11. The structure on the back side of the heat sink will be described in detail later.

The insulating plate 22 is an insulating material with excellent thermal conductivity. The insulating plate 22 is preferably made of highly thermally conductive ceramics such as aluminum oxide, aluminum nitride, and silicon nitride. Further, the insulating plate 22 is preferably made of an insulating resin such as an epoxy resin mixed with highly thermally conductive ceramics. The thickness of the insulating plate 22 is preferably 0.1 mm or more and 2 mm or less. The heat sink 23 and the conductive plate 21 are electrically insulated by the insulating plate 22.

The heat sink 23 is a conductive material with excellent thermal conductivity. The heat sink 23 is preferably made of copper, aluminum, or an alloy containing at least one of these. Furthermore, the heat sink 23 may have a plated film of nickel or the like formed on its surface. The thickness of the heat sink 23 is preferably 0.1 mm or more and 10 mm or less.

The conductive plate 21 is a conductive material. The conductive plate 21 is preferably made of copper, aluminum, or an alloy containing at least one of these. Furthermore, the conductive plate 21 may have a plated film of nickel or the like formed on its surface. The thickness of the conductive plate 21 is preferably 0.1 mm or more and 10 mm or less.

As the laminated substrate 20 having such a configuration, for example, a DCB (Direct Copper Bonding) substrate, an AMB (Active Metal Brazed) substrate, or a metal base substrate can be used. The laminated substrate 20 can conduct heat generated in the semiconductor element 24 during operation to a cooler (not shown) via the heat sink 23.

The heat sink 23 has a side surface between the front surface and the back surface. The side surface of the heat sink 23 refers to all the surfaces formed between two opposing main surfaces of the plate-shaped heat sink. In FIG. 3, the side surface of the heat sink 23 is a plane (YZ surface). However, the direction of the side surface of the heat sink 23 is not limited to this. The side surface of the heat sink 23 may be a curved surface. Further, the side surface of the heat sink 23 may have a depression or a protrusion. In this case, all the surfaces of the depressions and protrusions formed on the side surfaces are referred to as side surfaces.

FIG. 5 shows the bottom surface of the semiconductor module 10 of FIG. FIG. 6 is a cross-sectional view for explaining the shape of the extending portion 20b of the heat sink 23. As shown in FIG. As shown in FIG. 6, the heat sink 23 has an embedded part 20a embedded in the case 11, and an extension part 20b extending outward from the bottom surface of the case 11 (in the negative direction of the Z-axis). The length of the extending portion 20b of the substrate (20) extending downward (in the negative direction of the Z-axis) from the bottom surface of the case (11) is referred to as "extending amount."

As shown in FIGS. 5 and 6, the two laminated substrates 20 are arranged in the longitudinal direction and are located between the two fastening parts 14, with the fastening part 14 being located on the outer side. At this time, the outer edge of the two laminated substrates is a first edge 20c close to the fastening part 14, and the edge sandwiched between the two laminated substrates is a second edge 20d far from the fastening part 14. . The amount of extension E1 on the first end side 20c closer to the fastening portion 14 is smaller than the amount of extension E2 on the second end side 20d farther from the fastening portion 14. Preferably, E1/E2 is 0.3 or more and 0.9 or less. More preferably, E1/E2 is 0.5 or more and 0.8 or less. If it is too small, when the semiconductor module 10 is fastened to a heat sink, which will be described later, the gap between the heat sink 23 and the heat sink becomes large on the center side of the semiconductor module 10, and heat dissipation performance is inhibited. If it is too large, when the semiconductor module 10 is fastened to a heat sink, the gap between the heat sink 23 and the heat sink becomes large on the outer peripheral side of the semiconductor module 10, and heat dissipation performance is inhibited.

The back surface of the heat sink 23 has a first region 20e including a first end 20c close to the fastening portion, and a second region 20f including a second end 20d far from the fastening portion. The first region 20e and the second region 20f may be adjacent to each other with the boundary 20g in between. The amount of extension in the first region 20e is smaller than the amount of extension in the second region 20f. The extension amount E1 at the first end side 20c is smaller than the extension amount E3 at the boundary 20g. The extension amount E2 at the second end side 20d is the same as the extension amount E3 at the boundary 20g. Preferably, E1/E3 is 0.3 or more and 0.9 or less. More preferably, E1/E3 is 0.5 or more and 0.8 or less. If it is too small, when the semiconductor module 10 is fastened to a heat sink, which will be described later, the gap between the heat sink 23 and the heat sink becomes large on the center side of the semiconductor module 10, and heat dissipation performance is inhibited. If it is too large, when the semiconductor module 10 is fastened to a heat sink, the gap between the heat sink 23 and the heat sink becomes large on the outer peripheral side of the semiconductor module 10, and heat dissipation performance is inhibited. The position of the boundary 20g between the first end side 20c and the second end side 20d is such that the length from the first end side 20c to the second end side 20d is d1, and the length from the first end side to the boundary 20g is When d2, d2/d1 is preferably 0.1 or more and 1.0 or less. More preferably, d2/d1 is 0.2 or more and 0.8 or less. If it is too small, excessive stress will be applied to the first end side 20c when the semiconductor module 10 is fastened to a heat sink, which will be described later, and the semiconductor module 10 will be easily destroyed.

The bottom surface of the first region 20e may be a surface inclined with respect to the bottom surface of the case, and the amount of extension of the first region 20e may gradually decrease from the boundary 20g toward the first edge 20c. The amount of extension of the second region 20f may be constant from the boundary 20g to the second end (20d). The heat sink 23 of the substrate (20) may have a thickness thinner at the first end (20c) than at the second end (20d). In this way, when a plurality of laminated substrates are arranged side by side and the fastening part is arranged on the outside, the first end side facing the fastening part 14 is located on the outer circumferential side of the case that forms the outer shape of the semiconductor module 10. The amount of extension of the second end side 20c is smaller than the amount of extension of the second end side 20c, which is located toward the center of the case and faces the adjacent laminated substrate 20.

A method for manufacturing the semiconductor module 10 of this embodiment will be described. First, the laminated substrate 20 is prepared. Next, the semiconductor element 24 and wiring members (not shown) such as wires and external connection terminals are mounted on the laminated substrate 20. Next, the mounted multilayer substrate 20 and connection member 31 are set in a mold, and resin molding is performed. Finally, the semiconductor module 10 is manufactured by taking out the resin molded body from the mold and subjecting it to surface treatment such as deburring.

In order to manufacture the semiconductor module 10 in which the amount of extension of the first region 20e is smaller than the amount of extension of the second region 20f, for example, in the preparation process of the laminated substrate 20, the thickness of the first region 20e is thinned in advance. 20 can be used. Further, in the resin molding process, when setting the mounted multilayer substrate 20 in a mold, the amount of extension of the first region 20e can be set to be smaller than the amount of extension of the second region 20f. Moreover, in the surface treatment step, the first region 20e extending from the bottom surface of the molded body can be polished. Alternatively, when polishing the back surface of the heat sink 23, the first region 20e can be polished more than the second region 20f. The first edge (20c It is possible to manufacture a semiconductor module 10 in which the thickness of the substrate at ) is thinner than the thickness of the substrate at the second edge (20d).

The semiconductor device 30 will be explained using FIG. 7. FIG. 7 shows a cross-sectional view of the semiconductor device 30. The semiconductor device 30 includes a semiconductor module 10, a heat radiation member 31, a heat sink 32, and a fastening member 34. The heat dissipation member 31 is arranged between the bottom surface of the semiconductor module 10 and the top surface of the heat sink 32. The heat dissipation member 31 may be provided at least on the back surface of the heat dissipation plate 23 in plan view. It may be arranged over the entire bottom surface of the semiconductor module 10. The thickness of the heat dissipating member 31 is preferably 10 μm or more and 400 μm or less, more preferably 20 μm or more and 100 μm or less. The heat dissipating member 31 may be, for example, a paste-like thermally conductive grease made by mixing flexible grease or resin with a highly thermally conductive filler. Further, the heat conductive member 41 may be, for example, a heat conductive sheet made of a sheet-like resin in which a highly thermally conductive filler is dispersed. The heat sink 32 may be a radiation fin, a water cooling jacket, or the like. Further, the front surface of the heat sink 32 may be flat or curved slightly convexly toward the semiconductor module 10 side. The heat sink 32 may include a fastening portion 33 such as a screw hole. The fastening member 34 may be a screw or a clamp.

The semiconductor device 30 has a structure in which the semiconductor module 10 is pressed against the heat sink 32 by a fastening member 34 . For example, the head bearing surface of the fastening member 34 made of a screw contacts the front surface of the fastening part 14 of the case 11, and the body of the fastening member 34 penetrates the case 11 and is formed from a screw hole of the heat sink. It may be tightened into the fastening portion 33. Thus, the bottom surface of the heat sink 23 of the semiconductor module 10 is in close contact with the front surface of the heat sink 32 via the heat sink 31. By pressing the semiconductor module 10 against the heat sink 32 by the fastening member 34, the semiconductor module 10 approaches the heat sink 32 in the vicinity of the fastening member 34, and tends to lift off from the heat sink at a portion away from the fastening portion. At this time, since the amount of extension of the first end of the semiconductor module 10 near the fastening member 34 is smaller than the amount of extension of the second end of the semiconductor module 10 farther from the fastening member 34, lifting from the heat sink 32 is alleviated. Therefore, it is possible to suppress an increase in the distance between the heat dissipation plate 23 and the heat sink 32 of the semiconductor module 10, and to provide a semiconductor module that suppresses a decrease in heat dissipation performance. Further, when the semiconductor module 10 is pressed against the heat sink 32 by the fastening member 34, the upper surface of the semiconductor module 10 has a moderately curved convex shape, thereby preventing excessive stress from being applied to the first end side 20c. to prevent the semiconductor module 10 from being destroyed.
(Modification of the first embodiment)

8 to 11 are cross-sectional views for explaining modified examples of the extending portion 20b of the heat sink 23. FIG. 8 to 11 include a first end 20c close to the fastening part 14 and a second end 20d far from the fastening part 14. FIGS. Further, there is a first region 20e including a first edge 20c and a second region 20f including a second edge 20d, and the first region 20e and the second region 20f are adjacent to each other with a boundary 20g in between. . The amount of extension on the first end side 20c is smaller than the amount of extension on the boundary 20g and the second end side 20d.

As shown in FIG. 8, the amount of extension in the first region 20e may gradually decrease with a downwardly convex curved surface from the boundary 20g toward the first end side 20c. The amount of extension in the second region 20f may be constant.

As shown in FIG. 9, the boundary 20g may have a step in which the first region 20e extends smaller than the second region 20f. At this time, the amount of extension in the first region 20e and the second region 20f may be constant. Moreover, as shown in FIG. 10, it may have a plurality of steps whose extension amount decreases toward the first end side 20c. The amount of extension in the first region 20e and the second region 20f may be constant.

As shown in FIG. 11, the amount of extension in the first region 20e gradually decreases from the boundary 20g to the first edge 20c, and the amount of extension in the second region 20f also decreases from the boundary 20g to the second edge 20d. It may be possible to gradually decrease towards the end. However, also at this time, the extension amount E1 at the first end side 20c is smaller than the extension amount E3 at the boundary 20g and the extension amount E2 at the second end side 20d. Preferably, E1/E3 is 0.3 or more and 0.9 or less. More preferably, E1/E3 is 0.5 or more and 0.8 or less. Further, the extension amount E2 at the second end side 20d may be smaller than the extension amount E3 at the boundary 20g. Preferably, E2/E3 is 0.6 or more and 0.9 or less. More preferably, E2/E3 is 0.7 or more and 0.8 or less.

In the modified semiconductor module as well, lifting from the heat sink 32 is alleviated. Therefore, it is possible to suppress an increase in the distance between the heat dissipation plate 23 and the heat sink 32 of the semiconductor module 10, and to provide a semiconductor module that suppresses a decrease in heat dissipation performance.
(Comparative example of the first embodiment)

20 and 21 show comparative examples with respect to the first embodiment. FIG. 20 is a cross-sectional view of a semiconductor module 110 of a comparative example. The semiconductor module 110 has the same configuration as the semiconductor module 10 of the first embodiment (see FIG. 3) except for the structure of the bottom surface of the semiconductor module 110. As shown in FIG. 20, the heat sink 123 of the comparative example extends outward (in the negative direction of the Z-axis) from the bottom surface of the case 11. The thickness of the laminated substrate 120 and the heat sink 123 are constant, and the amount of extension from the bottom surface of the case 11 is constant. Therefore, the amount of extension of the edge near the fastening portion 14 and the amount of extension of the edge far from the fastening portion 114 are the same. In FIG. 20, two laminated substrates 120 are lined up in the longitudinal direction, and the fastening portion 14 is located outside the two laminated substrates 120. At this time, the outer edge of the two laminated substrates 120 is the edge closer to the fastening part 14, and the edge sandwiched between the two laminated substrates 120 is the edge farther from the fastening part 14. The amount of extension of the outer edges of the two laminated substrates is the same as the amount of extension of the edge on the center side of the semiconductor module 110 sandwiched between the two laminated substrates.

FIG. 21 shows a cross-sectional view of a semiconductor device 130 of a comparative example. A semiconductor device 130 of a comparative example includes a semiconductor module 110 having a structure different from that of the first embodiment, and a heat dissipation member 31, a heat sink 32, and a fastening member 34 similar to those of the first embodiment (see FIG. 6). The semiconductor device 130 of the comparative example uses a semiconductor module 110 in which the amount of extension of the heat sink 123 from the bottom surface of the case 11 is constant. Since the bottom surface of the fastening section of the case and the edge of the heat sink 123 on the fastening section 34 side are close to the front surface of the heat sink 32, the distance between the bottom surface of the heat sink 123 and the heat sink increases as the distance from the case fastening section increases. It has become. In this example, the semiconductor module 110 has an inverted V shape with respect to the front surface of the heat sink, and the distance between the heat sink 123 and the heat sink near the center of the two fastening members 34 is large. Therefore, such a semiconductor device 130 may cause a decrease in heat dissipation of the semiconductor module 110. Moreover, when the semiconductor module 10 is pressed against the heat sink 32 by the fastening member 34, excessive stress is applied to the first end side 20c, which may cause the semiconductor module 10 to be destroyed.

In the semiconductor module 10 of this embodiment, the amount of extension of the first end side closer to the fastening member 34 is smaller than the amount of extension of the second end side farther from the fastening member 34. Therefore, the distance between the heat sink 23 and the heat sink 32 of the semiconductor module 10 is suppressed from increasing. Such a semiconductor device 130 can suppress a decrease in heat dissipation performance of the semiconductor module.

(Second embodiment)
FIG. 12 shows a schematic cross-sectional view of the semiconductor module 10 of this embodiment, and FIG. 13 shows a schematic cross-sectional view of the semiconductor device 30. The semiconductor module 10 of this embodiment has the same configuration as the semiconductor module 10 of the first embodiment (see FIG. 3) except for the structure of the bottom surface. As shown in FIG. 12, the heat sink 23 of this embodiment extends outward from the bottom surface of the case 11 (in the negative direction of the Z-axis). The heat sink 23 has an embedded part 20a embedded in the case 11 and an extension part 20b extending outward (in the negative direction of the Z-axis) from the bottom surface of the case 11. The amount of extension of the end side 20c near the fastening part 14 on the outer peripheral side of the case is smaller than the amount of extension of the second end side 20d far from the fastening part 14 on the center side of the case. The bottom surface of the heat sink 23 in this embodiment has a continuous slope, and there is no boundary where the slope changes intermittently. The amount of extension gradually decreases from the second end side 20d to the first end side 20c.

As shown in FIG. 13, a semiconductor device 30 includes a semiconductor module 10 having a structure different from that of the first embodiment, and a heat dissipation member 31, a heat sink 32, and a fastening member 34 that are similar to those of the first embodiment (see FIG. reference). As described above, in the semiconductor module 10 of this embodiment, the amount of extension thereof gradually decreases from the second end side 20d to the first end side 20c. The semiconductor device 30 has a structure in which the semiconductor module 10 is pressed against the heat sink 32 by a fastening member 34 . By pressing the semiconductor module 10 against the heat sink 32 by the fastening member 34, the semiconductor module 10 approaches the heat sink 32 in the vicinity of the fastening member 34, and tends to lift off from the heat sink at a portion away from the fastening portion. At this time, since the amount of extension of the first end of the semiconductor module 10 near the fastening member 34 is smaller than the amount of extension of the second end of the semiconductor module 10 farther from the fastening member 34, lifting from the heat sink 32 is alleviated. Therefore, it is possible to suppress an increase in the distance between the heat dissipation plate 23 and the heat sink 32 of the semiconductor module 10, and to provide a semiconductor module that suppresses a decrease in heat dissipation performance. Further, when the semiconductor module 10 is pressed against the heat sink 32 by the fastening member 34, the upper surface of the semiconductor module 10 has a moderately curved convex shape, thereby preventing excessive stress from being applied to the first end side 20c. This can prevent the semiconductor module 10 from being destroyed.

(Third embodiment)
FIG. 14 shows a bottom view of the semiconductor module 10 of this embodiment. FIG. 15 shows an AA cross-sectional view of the semiconductor module 10. As shown in FIG. 14, the semiconductor module 10 of the present embodiment is a case having a rectangular shape in plan view, and two laminated substrates 20 having a rectangular shape in plan view are arranged side by side along the long side and the short side of the case, respectively. Four laminated substrates 20 extend outward from the bottom surface of the case 11 (in the negative direction of the Z axis). Furthermore, fastening portions 14 are provided at each of the four corners of the bottom surface. The amount of extension of the board 20 near the four corners of the case from the bottom of the case 11 is smaller than the amount of extension of the board 20 near the center of the case 11 from the bottom of the case 11.

On the short side (the side parallel to the Y-axis) of the laminated board, the extension amount at the first end side 20c1 facing the outer periphery of the case 11 is the side opposite to the first end side 20c1, which is adjacent to the center side of the case 11. The amount of extension is smaller than the amount of extension at the second end side 20d1 facing the matching substrate. The average value of the extension amount of the first end side 20c2 facing the outer periphery of the case 11 on the long side of the laminated board (the side parallel to the is smaller than the average value of the extension amount of the second end side 20d2 facing the adjacent substrate. Specifically, on the long sides of the laminated substrate, a second region 20f with a constant extension amount is located on the center side of the case 11, and a first region 20e with a smaller extension amount than the second region 20f is on the outer peripheral side of the case 11. It is in. On the long side of the multilayer substrate, the ratio of the first region 20e at the first end side 20c2 facing the outer periphery of the case 11 is equal to the ratio of the first area 20e at the second end side 20d2 of the board facing the adjacent board at the center side of the case. It is larger than the ratio of the first region 20e.

A boundary 20g between the first region 20e and the second region 20f intersects with a diagonal line of the case 11, which is rectangular in plan view. Preferably, each boundary 20g and the diagonal of the case 11 intersect at an angle of 60° or more and 120° or less. The boundary 20g may be a straight line or a curved shape that is convex toward the outer periphery of the case. Since the boundary 20g has a curved shape that is convex toward the outer periphery of the case, lifting from the heat sink can be more easily alleviated.

In such a semiconductor module 10 as well, lifting from the heat sink is alleviated. Therefore, it is possible to suppress the distance between the heat sink and the heat sink of the semiconductor module 10 from increasing.

(Fourth embodiment)
FIG. 17 shows a bottom view of the semiconductor module 10 of this embodiment. FIG. 18 shows an AA cross-sectional view of the semiconductor module 10. As shown in FIG. 17, in the semiconductor module 10 of this embodiment, one laminated substrate 20 extends outward (in the negative direction of the Z axis) from the bottom surface of the case 11. The laminated board 20 extends at a position offset to one side from the center of the bottom surface of the case 11. A fastening portion 14 is provided at each of the four corners of the bottom surface. There is a first end side 20c on the side closer to the fastening part 14, and a second end side 20d is on the side farther from the fastening part 14. At this time, the amount of extension on the first end side 20c is smaller than the amount of extension on the second end side. Further, the back surface of the heat sink 23 has a first region 20e including a first end 20c close to the fastening portion, and a second region 20f including a second end 20d far from the fastening portion. The first region 20e and the second region 20f are adjacent to each other with a boundary 20g in between. The amount of extension in the first region 20e is smaller than the amount of extension in the second region 20f, except for the boundary 20g with the second region 20f. The bottom surface of the first region 20e may be an inclined surface, and the amount of extension of the first region 20e may gradually decrease from the boundary 20g with the second region 20f toward the first edge 20c. The amount of extension of the second region 20f may be constant.

In such a semiconductor module 10 as well, lifting from the heat sink is alleviated. Therefore, it is possible to suppress the distance between the heat sink and the heat sink of the semiconductor module 10 from increasing.

(Fifth embodiment)
FIG. 18 shows a bottom view of the semiconductor module 10 of this embodiment. FIG. 19 shows an AA cross-sectional view of the semiconductor module 10. As shown in FIG. 17, in the semiconductor module 10 of this embodiment, one laminated substrate 20 extends outward (in the negative direction of the Z-axis) from the bottom surface of the case 11, which has a rectangular planar shape. The laminated board 20 extends at the center of the bottom surface of the case 11. The semiconductor module 10 includes fastening portions 14 near both ends in the longitudinal direction (X-axis direction). The amount of extension of the laminated board 20 from the bottom of the case 11 on the outer peripheral side of the case 11 near the fastening portion 14 is smaller than the amount of extension of the laminated board 20 from the bottom of the case 11 at the center of the case 11 . The bottom surface of the laminated substrate 20 may be curved convexly downward (in the negative direction of the Z axis). The laminated substrate has a rectangular planar shape, and the thickness of the heat sink 23 of the laminated substrate 20 is thicker at the center and thinner at the ends in the long side direction (X-axis direction) of the laminated substrate.

The back surface of the heat sink 23 has a first region 20e on each of the two end sides and a second region 20f in the center in the long side direction of the substrate (X-axis direction). The amount of extension in the first region 20e is smaller than the amount of extension in the second region 20f. The bottom surface of the first region 20e may be an inclined surface, and the amount of extension of the first region 20e may gradually decrease from the boundary 20g with the second region 20f toward the first edge 20c. The amount of extension of the second region 20f may be constant.

In such a semiconductor module 10 as well, lifting from the heat sink is alleviated. Therefore, it is possible to suppress the distance between the heat sink and the heat sink of the semiconductor module 10 from increasing.

10 Semiconductor module 11 Case 13 External connection terminal 14 Fastening section 20 Laminated substrate 20a Embedded section 20b Extension section 20c First edge 20d Second edge 20e First area 20f Second area 20g Boundary 21 Conductive plate 22 Insulating plate 23 Heat sink 24 Semiconductor element 25 Bonding member 30 Semiconductor device 31 Heat sink 32 Heat sink 33 Fastening section 110 Semiconductor module 120 Laminated substrate 123 Heat sink 130 Semiconductor device

Claims (9)

multiple semiconductor elements;
a plurality of substrates each having the semiconductor element mounted on its front surface;
The substrate includes a front surface of the plurality of substrates and each of the semiconductor elements, a back surface of the substrate extends from a bottom surface , and is located near both ends so as to sandwich the plurality of substrates in a plan view. a case having a fastening portion disposed between the case and the outer periphery ;
Equipped with
The amount of extension of the edges of the plurality of substrates near the fastening portions on the outer peripheral side of the case from the case bottom surface is such that the amount of extension of the edges of the plurality of substrates adjacent to the plurality of substrates on the case center side from the case bottom surface smaller than the extension of
semiconductor module. The back surface of the substrate includes a first region that extends less from the bottom of the case , and a second region that extends from the bottom of the case more than the first region and is continuous with the first region via a boundary. comprising an area,
The amount of extension of the first region gradually decreases from the boundary toward the outer periphery ,
The amount of extension of the second region is constant;
The semiconductor module according to claim 1 . having a step on the back surface of the plurality of substrates ;
The semiconductor module according to claim 1 . It has a plurality of steps whose extension amount decreases toward the fastening portion.
The semiconductor module according to claim 3. The fastening portion is a hole passing through the case.
The semiconductor module according to claim 1. The fastening portion is a recess in the case.
The semiconductor module according to claim 1. The case has a rectangular shape in plan view, at least two of the substrates are arranged side by side along the long side of the case, and at least one pair of the fastening portions are provided between the short side of the case and the substrate,
The amount of extension at an end side of one of the substrates facing the short side of the case is smaller than the amount of extension at an end side of one of the substrates facing the other adjacent substrate.
The semiconductor module according to claim 1. The case has a rectangular shape in plan view, at least two of the substrates are arranged side by side along the long sides and short sides of the case, and the fastening parts are provided at the four corners of the case,
The amount of extension at an edge of one of the substrates facing the outer periphery is smaller than the amount of extension at an edge of one of the substrates facing the other adjacent substrate.
The semiconductor module according to claim 1. The semiconductor module according to claim 1;
a heat dissipation member disposed on the bottom surface of the semiconductor module;
a heat sink disposed on the bottom surface of the semiconductor module via the heat dissipation member;
a fastening member that fastens the semiconductor module and the heat sink;
Equipped with
The semiconductor module is a semiconductor device whose top surface is curved in a convex shape.

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