Semiconductor module

Abstract

The semiconductor module includes a housing that internally houses semiconductor elements and is integrally molded with resin; a first terminal provided on the upper part of the housing and mounting a bus bar of a flat and elongated metal conductor; a second terminal provided on the upper part of the housing and adjacent to the first terminal; and a rib provided between the first terminal and the second terminal. The rib has a protrusion protruding toward the bus bar.

Description

Technical Field

[0001] The present invention relates to a semiconductor module, and particularly to a semiconductor module in which a bus bar is mounted on a resin housing. Background Art

[0002] A semiconductor module mounted on an electrical device is designed such that the creepage distance and the air distance between the terminals of the module can ensure a predetermined size. The creepage distance is the shortest distance along the surface of an insulator between the terminals, and the air distance is the shortest distance through the space between the terminals.

[0003] The semiconductor module is configured by housing semiconductor elements such as diodes and transistors in a resin housing, arranging a metal substrate at the bottom of the housing, and arranging a plurality of terminals at the upper part of the housing. The whole is an encapsulated structure.

[0004] In a semiconductor module having such a structure, in order to ensure the creepage distance and the air distance between the terminals provided at the upper part of the housing, the following prior arts have been proposed.

[0005] First, ribs (insulating wall portions) are provided between the terminals to increase the creepage distance and the air distance between the terminals (Patent Document 1). Second, a groove is provided on the surface of the housing to increase the creepage distance (Patent Document 2).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Laid-Open No. 6-21603

[0009] Patent Document 2: Japanese Patent Laid-Open No. 2003-303939 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] However, in the above-described configurations in which ribs or grooves are provided, there are cases where it is difficult to ensure sufficient creepage distance and air distance. For example, in a structure in which a plurality of semiconductor modules are arranged and a bus bar is fixedly mounted on a common terminal of each semiconductor module with a screw, the following problems occur.

[0012] That is, when the bus bar is mounted, the bus bar may be mounted deviating from a predetermined position. At this time, the bus bar may come into contact with the surface of the rib. Then, the creepage distance and the air distance between the second terminal adjacent to the first terminal to which the bus bar is mounted and the bus bar become below a preset value. In particular, when a groove is provided to increase the creepage distance, the effect of the groove disappears.

[0013] In addition, when installing the bus bar, if the space distance between the bus bar and the groove wall is short, this space distance will become part of the creepage distance between the first terminal where the bus bar is installed and the adjacent second terminal. As a result, the creepage distance between these terminals becomes less than the preset value.

[0014] An object of the present invention is to provide a semiconductor module that can ensure the creepage distance and the space distance between the second terminal adjacent to the first terminal where the bus bar is installed and the bus bar when installing the bus bar.

[0015] Problem solution

[0016] The present invention includes a housing that houses semiconductor elements therein and is integrally formed of resin;

[0017] A first terminal that is provided on the upper part of the housing and mounts a bus bar made of a flat and elongated metal conductor;

[0018] A second terminal that is provided on the upper part of the housing and is adjacent to the first terminal; and

[0019] A rib provided between the first terminal and the second terminal,

[0020] The rib has a protrusion protruding toward the bus bar.

[0021] A first terminal and a second terminal are provided on the upper part of the housing, and a rib is provided between these terminals. When the bus bar is installed on the first terminal, the range where the bus bar can move is up to the position where it contacts the protrusion of the rib. Since the protrusion of the rib becomes an obstacle, the bus bar does not contact the surface of the rib. Thus, it is possible to prevent the bus bar from contacting the surface of the rib. Once the bus bar contacts the surface of the rib, the creepage distance and the space distance between the bus bar and the second terminal will become short. However, in the present invention, due to the protrusion of the rib, the bus bar does not contact the surface of the rib. Thus, the creepage distance and the space distance between the bus bar and the second terminal can be the predetermined design values.

[0022] By providing an inclined surface on the protrusion, when molding the rib and the housing with resin, the whole can be simply pulled out from the vertical direction. In addition, since the bus bar can descend along the inclined surface to the installation position, the installation is simple.

[0023] The protrusion can be provided near the center or at multiple positions of the rib. If provided at multiple positions, rotation of the bus bar can be prevented when installing the bus bar.

[0024] By providing a groove around the first terminal and the second terminal, the creepage distance between the bus bar and the second terminal can be increased by an amount equivalent to the creepage length of the groove. The creepage distance that can be increased by this groove can be reliably ensured because the bus bar cannot move further toward the rib side due to the protrusion of the rib.

[0025] Effect of the Invention

[0026] In the present invention, by providing protrusions on the rib body, it is possible to prevent the bus bar from coming into contact with the surface of the rib body. Therefore, the creepage distance and the space distance between the bus bar or the first terminal for screw fixing of the bus bar and the adjacent second terminal can be surely set to the design values. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view of a semiconductor module according to an embodiment of the present invention.

[0028] Figure 2 is a plan view of the semiconductor module.

[0029] Figure 3 is a circuit diagram of the semiconductor module.

[0030] Figure 4 is Figure 2 the cross-sectional view taken along line A - B in

[0031] Figure 5 shows a top view when four semiconductor modules are arranged at regular intervals in the second direction (Y direction) and a bus bar is installed.

[0032] Figure 6 (A) and (B) are diagrams showing the creepage distance in the plan view of the semiconductor module and the creepage distance in the cross-sectional view taken along line C - D, respectively.

[0033] Figure 7 is a diagram showing the creepage distance when there is no notch in the wall 70.

[0034] Figure 8 (A) and (B) are diagrams showing the space distance in the plan view of the semiconductor module and the space distance in the cross-sectional view taken along line C - D, respectively.

[0035] Figure 9 (A) - (D) are diagrams showing other embodiments, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0036] Figure 1 is a perspective view of a semiconductor module according to an embodiment of the present invention. Figure 2 is the plan view of the semiconductor module.

[0037] The semiconductor module includes a resin-made housing 1 having a rectangular parallelepiped shape, and first terminals 2, second terminals 3, and third terminals 4 for screw fixing, which are provided on the housing 1 and arranged at a predetermined interval in the first direction (X direction), i.e., the long side direction.

[0038] ​​​​​​​​​On the upper surface of the housing 1, a first terminal surface 21, a second terminal surface 31, and a third terminal surface 41 for mounting the first terminal 2, the second terminal 3, and the third terminal 4 respectively are formed. The first terminal surface 21 mounts the first terminal 2, the second terminal surface 31 mounts the second terminal 3, and the third terminal surface 41 mounts the third terminal 4. Each of the terminals 2 to 4 is formed by inserting a vertically formed metal sheet pre-shaped into a terminal shape into the housing 1 and bending the upper end portion thereof. A screw insertion hole is formed in the central portion of each of the terminals 2 to 4.

[0039] Two diodes D1 and D2 as semiconductors are housed in the housing 1. Figure 3 This is a circuit diagram. The cathodes of the diode D1 and the diode D2 are connected to form a common terminal C, and the anode of the diode D1 is formed as a first anode terminal A, and the anode of the diode D2 is formed as a second anode terminal B respectively.

[0040] The common terminal C is connected to the first terminal 2 within the housing 1. The first anode terminal A is connected to the second terminal 3 within the housing 1. The second anode terminal B is connected to the third terminal 4 within the housing 1. The first terminal 2 is a terminal for mounting a bus bar by screw fixation as described later. The second and third terminals 3 and 4 are terminals for mounting the end of a cable by screw fixation. In the terminal surfaces 21, 31, and 41, screw portions 20, 30, and 40 are formed at the lower portions of the terminals 2 to 4. In order to screw-fix the bus bar or the cable end to the terminals 2 to 4, the screw hole portion of the bus bar or the cable end is positioned on each of the terminals 2 to 4, and through a washer or the like, it is screwed from above to the screw portions 20 to 40.

[0041] Screw fixing portions 100 and 101 for fixing the housing are provided at both ends of the housing 1 in the first direction (X direction). The screw fixing portions 100 and 101 are used to fix the housing 1 to a substrate within the outer shell of an electrical device with screws.

[0042] The upper portion of the housing 1 is provided with a first rib 5 and a second rib 6. The first rib 5 and the second rib 6 are provided in the second direction (Y direction) perpendicular to the first direction (X direction). The first rib 5 is provided between the first terminal 2 and the second terminal 3, and the second rib 6 is provided between the second terminal 3 and the third terminal 4. These ribs 5 and 6 are used to increase the creepage distance and the clearance distance between the terminals. In addition, these ribs 5 and 6 are integrally formed with the housing 1.

[0043] The first rib body 5 has a protrusion 51 at the central part of the surface 50. The protrusion 51 faces the first terminal 2 for the bus bar. The protrusion 51 is formed integrally with the rib body 5 in the vertical direction at the central part of the second direction (Y direction) of the surface 50. In addition, the upper end part of the protrusion 51 is an inclined surface 51a that slopes downward from the upper end. The lower part connected to the inclined surface 51a is a vertical surface. Thus, the inclined surface 51a and the vertical surface connected thereto constitute the protrusion 51. Thus, the inclined surface 51a becomes a draft surface, making it easier for the mold to be demolded during molding.

[0044] On the upper surface of the housing 1, around each of the terminals 2 to 4, more specifically, around each of the terminal surfaces 21, 31, 41, a first groove 7, a second groove 8, and a third groove 9 are provided. The first groove 7 is provided in front of and behind the first terminal 2 and on the left side of the first terminal 2 ( Figure 1 : on the side of the first rib body 5). The second groove 8 is provided in front of and behind the second terminal 3 and on the left side and the right side of the second terminal 3 ( Figure 1 : on the side of the second rib body 6 and on the side of the first rib body 5). The third groove 9 is provided in front of and behind the third terminal 4 and on the right side of the third terminal 4 ( Figure 1 : on the side of the second rib body 6).

[0045] The first groove 7 has a first wall 70 provided outside the housing 1. A notch 71 is formed at the central part of the first wall 70. The first wall 70 and the notch 71 are provided in front of and behind the first terminal 2. The notch 71 is used for draining water from the first groove 7. The second groove 8 has a second wall 80 provided outside the housing 1. A notch 81 is formed at the central part of the second wall 80. The second wall 80 and the notch 81 are provided in front of and behind the second terminal 3. The notch 81 is used for draining water from the groove 8. The third groove 9 has a third wall 90 provided outside the housing 1. A notch 91 is formed at the central part of the third wall 90. The third wall 90 and the notch 91 are provided in front of and behind the third terminal 4. The notch 91 is used for draining water from the third groove 9.

[0046] The heights of the respective walls 70, 80, 90 are set to be lower than the respective terminal surfaces 21, 31, 41.

[0047] Figure 4 is Figure 2 the A - B cross-sectional view. As shown in the figure, the height of the first terminal surface 21 (the height from the bottom surface of the housing 1) is H1, the height of the first wall 70 is H2, and H1 - H2 = h1. The height (thickness) of the first terminal 2 is h2. h1 + h2 = h3. h3 is the distance between the bottom surface of the bus bar 10 and the upper surface of the first wall 70. Setting the distance between the bottom surface of the bus bar 10 and the upper surface of the wall 70 as h3 is an important configuration for ensuring that the creepage distance d1 is set to the design value, as will be described later.

[0048] The semiconductor module thus formed is mounted on a substrate provided in an electrical device, and then the bus bar or the end of the cable is fixed to each semiconductor module with screws.

[0049] Figure 5 The plan view shows four semiconductor modules arranged at regular intervals in the second direction (Y direction) with a bus bar installed.

[0050] The four semiconductor modules M1 to M4 are respectively fixed to the substrate in the housing of the electrical device with screws through the screw fixing parts 100 and 101 provided at both ends of the housing 1.

[0051] The bus bar 10, which is a flat and elongated metal conductor, Figure 5 When it is closest to the rib body 5, it contacts the protrusion 51 of the first rib body 5 provided on each housing 1. Generally, the bus bar 10 does not contact the protrusion 51 of the rib body 5 during installation.

[0052] Next, use Figures 6 - 8 to illustrate the creepage distance d1 and the air distance d2 between the first terminal 2 and the adjacent second terminal 3. The creepage distance d1 refers to the shortest distance measured along the surface of the insulator between the terminals 2 and 3, and the air distance d2 refers to the shortest distance passing through the space between the terminals 2 and 3.

[0053] Figure 6 (A) is the plan view of a housing 1, showing the creepage distance d1 from the upper surface of the housing 1. In addition, Figure 6 (B) shows Figure 6 The cross-sectional view of C-D of (A). In these figures, the points A, B, C, and D represent the positions of the grooves 7 or 8 for measuring the creepage distance d1 in the up and down direction.

[0054] When considering the creepage distance, it is examined whether there is an air distance less than 1 mm. That is, when the air distance is less than 1 mm, this air distance becomes part of the creepage distance. Therefore, in this part, the creepage distance is not the distance measured along the insulator. At this time, when the thickness of the first terminal 2 is less than 1 mm, in the state where the bus bar 10 is installed, the distance h2 between the lower surface of the bus bar 10 and the first terminal surface 21 is less than 1 mm. Therefore, the distance h2 becomes part of the creepage distance d1 (refer to Figure 4 ). That is, when the creepage distance d1 is measured from the side of the first terminal 2, the creepage distance d1 is the bottom surface of the bus bar 10 the first terminal surface 21 the first groove 7 the side surface of the first rib body 5 the second groove 8 the second terminal surface 31 the total distance up to the second terminal 3. In Figure 4Among them, the distance indicated by the thick line represents a part of the creepage distance d1.

[0055] The following will detail the case where the bottom surface of the bus bar 10 is the starting point of the creepage distance d1 when the thickness of the first terminal 2 is less than 1 mm.

[0056] As Figure 4 shown, the distance h2 between the bottom surface of the bus bar 10 and the first terminal surface 21 is less than 1 mm. Therefore, insulation cannot be ensured between the first terminal 2 and the bus bar 10. Therefore, the starting point P of the creepage distance d1 is not the end of the first terminal 2, but the bottom surface of the bus bar 10 facing the first terminal surface 21. The creepage distance d1 starts from point P, passes through the first terminal surface 21, from point A to point B of the first groove 7, and reaches the upper surface of the first wall 70.

[0057] In addition, the height H2 of the first wall 70 is formed to be only h1 lower than the height H1 of the first terminal surface 21. In addition, the height of the first terminal 2 is h2. Therefore, by setting H2 such that the distance h3 (= h1 + h2) between the bottom surface of the bus bar 10 and the upper surface of the first wall 70 is 1 mm or more, the spatial distance of h3 does not become part of the creepage distance. That is, the creepage distance d1 is measured along the upper surface of the first wall 70.

[0058] For the above reasons, the creepage distance d1 in Figure 4 、 Figure 6 is the distances from (1) to (13) as follows.

[0059] (1) The starting point P of the bottom surface of the bus bar 10 (refer to Figure 4 )

[0060] (2) (Vertically descending from the wall surface of the first groove 7)

[0061] (3) The bottom surface of the first groove 7 (obliquely passing through the bottom surface of the first groove 7)

[0062] (4) (Obliquely rising from the wall surface of the first groove 7)

[0063] (5) The first wall 70 (obliquely passing through the upper surface of the first wall 70)

[0064] (6) (The side surface of the first rib body 5)

[0065] (7) (Horizontally passing through the outside of the side surface of the first rib body 5)

[0066] (8) The second wall 80 (obliquely passing through the upper surface of the second wall 80)

[0067] (9) (Sloping down from the wall surface of the second groove 8)

[0068] (10) The bottom surface of the second groove 8 (Passing obliquely through the bottom surface of the groove 8)

[0069] (11) (Sloping up from the wall surface of the second groove 8)

[0070] (12) The second terminal surface 31

[0071] (13) The second terminal 3

[0072] In addition, in Figure 6 , the creepage distance d1 is shown as vertically descending (or ascending) from B to D, but in fact, it descends (or ascends) obliquely as in the above (4)(9)(11).

[0073] As a modification, when the thickness of the first terminal 2 is 1 mm or more, h2 has a sufficient length. At this time, the starting point P of the creepage distance d1 is the left end of the first terminal 2 ( Figure 4 ). The creepage distance d1 is replaced by the following (1a)(1b) instead of the above (1).

[0074] (1a) The left end of the first terminal 2 ( Figure 4 ) of the starting point P (not shown)

[0075] (1b) The distance from the first terminal surface 21 to the first groove 7

[0076] As described above, in Figure 4 the illustrated embodiment, the creepage distance d1 starts from the starting point P (refer to Figure 4 ) on the bottom surface of the bus bar 10 and takes the grooves 7 and 8 as the paths on the left and right sides of the first rib 5. Thus, a sufficient creepage distance d1 can be ensured.

[0077] As a reference example, the creepage distance d1 when the height of the first wall 70 is the same as that of the first terminal surface 21, that is, H1 = H2, is described. At this time, the creepage distance d1 becomes shorter. Refer to Figure 7 for the reason.

[0078] In Figure 7In the embodiment, although the first groove 7 is provided, the height H2 of the first wall 70 is the same as the height H1 of the first terminal surface 21. As described above, when h2 is less than 1 mm, the spatial distance of h2 is measured as a part of the creepage distance. Therefore, the starting point P' of the creepage distance d1 is the bottom surface of the busbar 10 facing the end of the first wall 70. That is, the groove 7 provided to increase the creepage distance cannot be considered as a part of the creepage distance d1.

[0079] Specifically, in the creepage distance d1, the above (1) to (7) are changed to the following (14) to (16). The above (8) and thereafter are the same in the reference example.

[0080] (14) The starting point P' of the bottom surface of the busbar 10 (see Figure 7 )

[0081] (15) (Vertically descending from P' to the outer end of the upper surface of the first wall 70.)

[0082] (16) It passes linearly from the first wall 70 to the side surface of the first rib body 5 .

[0083] Therefore, in the reference example, the Figure 4 In contrast, the vertical and horizontal connection distances in the first slot 7 cannot be utilized flexibly, and the creepage distance d1 becomes shorter.

[0084] As another reference example, the creepage distance d1 is described when the protrusion 51 is not provided on the first rib 5. In this configuration, the busbar 10 may contact the surface of the first rib 5. Furthermore, once the busbar 10 contacts the surface of the first rib 5, the starting point of the creepage distance d1 is the contact point regardless of the height of the first wall 70. Therefore, the creepage distance d1 is shorter.

[0085] In this embodiment, if Figure 4 As shown, since the height of the first wall 70 is reduced to H2, the starting point P of the creepage distance d1 is the position where the busbar 10 faces the first terminal surface 21 (the position facing the inner side A of the first groove 7). Therefore, the first groove 7 is reliably a part of the creepage distance d1.

[0086] As described above, in this embodiment, by providing the protrusion 51 of the first rib 5 and making the height of the first wall 70 lower than the first terminal surface 21, when the busbar 10 is installed, the first groove 7 can be a part of the creepage distance d1. In addition, if the height H2 of the first wall 70 is set to a height that makes h1+h2=h3 greater than 1mm, the safety standard can be met. In addition, if h1 is set to be greater than 1mm, since h1+h2>1mm, even if the first terminal 2 is replaced with a terminal with a thinner h2, the creepage distance d1 of reliable insulation can be ensured.

[0087] Next, the spatial distance d2 will be described.

[0088] Figure 8 (A) is a top view of the housing 1, showing the spatial distance d2 from the upper surface of the housing 1 from above. Additionally, Figure 8 (B) shows Figure 8 a cross-sectional view taken along line C-D of (A).

[0089] The spatial distance d2 is the shortest distance through space between the first terminal 2 and the adjacent second terminal 3. In the state where the bus bar 10 is installed, as shown in the figure, the position Q where the right end portion of the bus bar 10 faces the side surface of the first rib 5 is the starting point. Therefore, the spatial distance d2 is the shortest distance in space from Q to the side surface of the bus bar 10 to the second terminal 3. When viewed from the front, as Figure 8 (B) shows, the spatial distance d2 is horizontal.

[0090] From Figure 8 (A) and (B), it can be seen that the spatial distance d2 can effectively ensure a thickness equivalent to that of the protrusion 51 of the first rib 5.

[0091] Figure 9 Another embodiment is shown. Figure 9 (A)-(C) show the shape of the protrusion 51. In Figure 9 (A), when viewed from the front, the protrusion 51 is triangular. In Figure 9 (B), when viewed from the front, the protrusion 51 is formed downward from the central portion of the first rib 5. Figure 9 (C) is a top view, and the protrusion 51 is formed near the left and right sides of the rib 5. Thus, rotation of the bus bar 10 can be prevented when the bus bar 10 is installed. At this time, as shown in the figure, the two protrusions 511 and 512 need to be slightly offset from the left and right ends of the rib 5 and located inside the front and rear first grooves 7. Additionally, the two protrusions 511 and 512 need to be formed at positions facing the first terminal surface 21. This is to effectively obtain the effect of the first groove 7 (increasing the creepage distance). Figure 9 (D) shows an example where the position of the screw hole 120 of the bus bar 10 is slightly eccentric to the right. In this example, the bus bar 10 can be installed at a position offset from the first rib 5. When the bus bar 10 is installed upside down, the left end portion of the bus bar 10 will touch the first rib 5 and cannot be installed. Thus, the creepage distance d1 and the spatial distance d2 can be extended. Additionally, it is possible to prevent incorrect installation direction of the bus bar 10.

[0092] As described above, in the present embodiment, by providing the protrusion 51 on the first rib 5, when the bus bar 10 is installed, the creepage distance between the bus bar 10 and the adjacent terminals can be effectively ensured. In addition, the space distance can also be extended.

[0093] Description of Reference Numerals

[0094] 1 Housing

[0095] 2 First Terminal

[0096] 3 Second Terminal

[0097] 4 Third Terminal

[0098] 5 First Rib

[0099] 6 Second Rib

[0100] 51 Protrusion

Claims

1. A semiconductor module comprising a housing that houses semiconductor elements therein and is integrally molded with resin; a first terminal surface provided on the upper part of the housing; a second terminal surface provided on the upper part of the housing, adjacent to the first terminal surface; a first terminal mounted on the first terminal surface and mounting a bus bar of a flat and elongated metal conductor; a second terminal mounted on the second terminal surface; and a rib provided between the first terminal and the second terminal, the rib having a protrusion protruding toward the bus bar, the protrusion capable of preventing the bus bar from contacting the surface of the rib, a groove is provided around the first terminal and the second terminal, the protrusion is offset from the left and right ends of the rib and is provided inside the left and right grooves among the grooves provided around the first terminal.

2. The semiconductor module according to claim 1, wherein the protrusion has an inclined surface that slopes downward from the upper end.

3. The semiconductor module according to claim 2, wherein the protrusion has a vertical surface extending downward from the inclined surface.

4. The semiconductor module according to any one of claims 1 to 3, wherein the protrusion is provided near the center of the rib.

5. The semiconductor module according to any one of claims 1 to 3, wherein the protrusion is provided at multiple locations on the rib.

6. The semiconductor module according to any one of claims 1 to 3, further comprising a first groove formed around the first terminal surface and having a first wall on the outside of the housing; and a second groove formed around the second terminal surface and having a second wall on the outside of the housing, the rib stands up from the first groove and the second groove to separate the first wall and the second wall, and is formed between the first terminal and the second terminal, the height of the first wall is set to be lower than the height of the first terminal surface.

7. The semiconductor module according to claim 6, wherein the height of the second wall is set to be the same as the height of the first wall.

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