Semiconductor equipment

Abstract

The present invention provides a semiconductor device that enables improved uniformity of pressure contact between a semiconductor element and a thermal compensation plate. [Solution] According to this embodiment, the semiconductor device comprises a semiconductor element 100 and a frame 102. The semiconductor element has a first electrode surface and a second electrode surface facing the first electrode surface. The frame is formed around the semiconductor element and has an opening to the first electrode surface. The frame has a first structural part 103 and a second structural part 104a. The first structural part extends inward from the end of the semiconductor element toward the first electrode surface and has a first surface 200 facing the first electrode surface. The second structural part extends further inward from the first structural part toward the first electrode surface and has a second surface 202 that is different from the first surface facing the first electrode surface.

Description

Technical Field

[0001] Embodiments of the present invention relate to semiconductor devices.

Background Art

[0002] There is a semiconductor device in which a heat compensation plate is pressed against an electrode surface of a semiconductor element for heat dissipation of the internal semiconductor element. In this case, a frame is formed around the semiconductor element for alignment. Also, an adhesive is provided between this frame and the semiconductor element.

[0003] However, it is difficult to control the bleeding of the adhesive, and there is a risk that the bled adhesive will be pressed by the heat compensation plate. In such a case, the bonding property between the semiconductor element and the heat compensation plate deteriorates, resulting in a non-uniform pressing state.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a semiconductor device capable of improving the uniformity of the pressure contact between a semiconductor element and a heat compensation plate.

Means for Solving the Problems

[0006] According to this embodiment, the semiconductor device comprises a semiconductor element and a frame. The semiconductor element has a first electrode surface and a second electrode surface facing the first electrode surface. The frame is constructed around the semiconductor element and has an opening to the first electrode surface. The frame has a first structural part and a second structural part. The first structural part is a first structural part that extends inward from the end of the semiconductor element towards the first electrode surface and has a first surface facing the first electrode surface. The second structural part is a second structural part that extends further inward from the first structural part towards the first electrode surface and has a second surface different from the first surface facing the first electrode surface. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic cross-sectional view of the semiconductor device of this embodiment. [Figure 2] A top view showing an example of the configuration of a semiconductor device chip. [Figure 3] Cross-sectional view AA' of a semiconductor device. [Figure 4] A schematic diagram of the top surface of a semiconductor device chip as seen from the first electrode block side. [Figure 5] Cross-sectional view of BB' in Figure 4. [Figure 6] Cross-sectional view of CC' in Figure 4. [Figure 7] Cross-sectional view of the frame in the comparative example. [Figure 8] A diagram showing the side view of the second structural section. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same and similar components will be denoted by the same reference numerals, and components that have already been described will be omitted from the description as appropriate.

[0009] (First Embodiment) Figure 1 is a schematic cross-sectional view of the semiconductor device of this embodiment. The semiconductor device 1 of this embodiment is, for example, a pressure-contact type semiconductor device. The semiconductor device 1 of this embodiment is, for example, a PPI (Press Pack IEGT).

[0010] The semiconductor device 1 of this embodiment includes a plurality of semiconductor element chips 10, a housing 12, a resin frame 14, a first thermal compensation plate 16a, a second thermal compensation plate 16b, a first electrode block 18, a second electrode block 20, a first flange 22, a second flange 24, a first protective material 26, a second protective material 28, a first metal plate 30, a second metal plate 32, and a third metal plate 34.

[0011] The semiconductor device 1 of this embodiment has multiple semiconductor element chips 10 arranged inside. The semiconductor element chips 10 have a rectangular planar shape, for example, with sides of 10 mm to 20 mm. Details of the semiconductor element chips 10 will be described later with reference to Figures 2 to 6.

[0012] The semiconductor chip 10 is placed inside the housing (first frame) 12. The housing 12 is annular and made of, for example, ceramic. The housing 12 is, for example, cylindrical. The inner diameter of the housing 12 is, for example, 80 mm or more. The radial thickness of the housing 12 is, for example, 4 mm or more and 20 mm or less.

[0013] The resin frame 14 is provided inside the housing 12. At least a portion of the resin frame 14 is provided between the first electrode block 18 and the second electrode block 20. The resin frame 14 is made of resin. The resin frame 14 holds a plurality of semiconductor element chips 10. The resin frame 14 has the function of ensuring an insulating distance between the semiconductor element chips 10 and aligning the plurality of semiconductor element chips 10.

[0014] The first thermal compensation plate 16a is provided on the first side of the semiconductor element chip 10. The second thermal compensation plate 16b is provided on the second side of the semiconductor element chip 10. The first thermal compensation plate 16a and the second thermal compensation plate 16b are made of materials with a thermal expansion coefficient close to that of the semiconductor element chip 10. For example, if the semiconductor element of the semiconductor element chip 10 is silicon, molybdenum, which has a thermal expansion coefficient close to that of silicon, is used as the material.

[0015] The first electrode block 18 is provided on the first surface side of the semiconductor element chip 10. Also, the second electrode block 20 is provided on the second surface side of the semiconductor element chip 10. The first electrode block 18 and the second electrode block 20 are, for example, cylindrical in shape.

[0016] The first electrode block 18 is provided in contact with the heat compensation plate 16a, and the second electrode block 20 is provided in contact with the heat compensation plate 16b. The first electrode block 18 and the second electrode block 20 are formed of a metal, for example, copper.

[0017] The first flange 22 is provided around the first electrode block 18. The first flange 22 is annular. The first flange 22 is formed of a metal, for example, copper or stainless steel. The first electrode block 18 is, for example, an emitter pressure contact electrode plate, and the second electrode block 20 is a collector pressure contact electrode plate.

[0018] The first flange 22 connects the first electrode block 18 and the housing 12. The first flange 22 is connected to the housing 12 via the first metal plate 30 and the second metal plate 32. The first metal plate 30 and the second metal plate 32 are formed of a metal that has, for example, a higher melting point than the first flange 22 and good adhesion to ceramics. [[ID=???]]

[0019] The second flange 24 is provided around the second electrode block 20. The second flange 24 is annular. The second flange 24 is formed of a metal, for example, copper or stainless steel. The second flange 24 connects the second electrode block 20 and the housing 12. The second flange 24 is connected to the housing 12 via the third metal plate 34. The third metal plate 34 is formed of a metal that has, for example, a higher melting point than the second flange 24 and good adhesion to ceramics. The third metal plate 34 is formed of, for example, an iron-nickel alloy.

[0020] It seems there is a typo in your provided text where "[[ID=???]] " is present. It should probably be something like " " for proper numbering continuity. If you have any further questions or need more help, feel free to ask.Here, a configuration example of the semiconductor element chip 10 will be described. FIG. 2 is a top view showing a configuration example of the semiconductor element chip 10. As shown in FIG. 2, the semiconductor element chip 10 includes a semiconductor element 100 and a frame 102. In FIG. 2, the gate pad electrode 100g of the semiconductor element 100 is also illustrated.

[0021] The semiconductor element 100 has a first electrode surface and a second electrode surface facing the first electrode surface. This semiconductor element 100 is, for example, an IEGT (Injection Enhanced Gate Transistor) using silicon (Si). IEGT is an IGBT (Insulated Gate Bipolar Transistor) having an electron injection promotion effect.

[0022] The peripheral portion of the semiconductor element 100 is, for example, subjected to SIPOS (Semi-Insulated POlycrystalline Silicon) passivation in order to stably maintain a high breakdown voltage of, for example, 4.5 kV. On top of that, the frame 102 is adhered for ensuring an insulating path and alignment during assembly.

[0023] The frame 102 is, for example, made of a resin material. The frame 102 is formed around the semiconductor element 100 and has an opening with respect to the first electrode surface of the semiconductor element chip 10. The frame 102 faces from the end of the semiconductor element 100 toward the inside of the first electrode surface, and has a first structure portion 103 whose first surface facing the first electrode surface has a first gradient with respect to the first electrode surface, and second structure portions 104a to 104d that further face from the first structure portion 103 toward the inside of the first electrode surface and have a second surface facing the first electrode surface. In the present embodiment, the second structure portions 104a to 104d have a convex shape, but are not limited thereto. For example, similar to the first structure portion 103, it is also possible to configure to surround the outer peripheral portion of the semiconductor element 100.

[0024] Figure 3 is a cross-sectional view AA' of the semiconductor device 100. As shown in Figure 3, the semiconductor device has a first pad electrode 100a on the first electrode surface and a second pad electrode 100b on the second electrode surface opposite to the first electrode surface. The area between the first pad electrode 100a and the second pad electrode 100b is the semiconductor device region 100c. The first pad electrode 100a is, for example, an emitter electrode. The second pad electrode 100b is, for example, a collector electrode. The gate pad electrode 100g (see Figure 2) is, for example, a gate electrode. In addition, an aluminum (Al) layer may be formed on the upper surface (z direction) of the first pad electrode 100a and the lower surface of the second pad electrode 100b.

[0025] The semiconductor element 100 is not particularly limited as long as it is a device equipped with electrodes on the top and bottom, and may be a diode such as an FRD (Fast Recovery Diode). It may also be a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Furthermore, for example, an IEGT and an FRD may be mounted together. It may also be an RC-IEGT (Reverse Conducting-IEGT) in which the diode and IEGT are integrated into a single chip. Moreover, it is not limited to silicon, but may also be a device using silicon carbide (SiC).

[0026] Figure 4 is a schematic top view of the semiconductor element chip 10 as seen from the first electrode block 18 side. Referring to Figure 1, as shown in Figure 4, the semiconductor element chip 10 is pressed against the electrode blocks 18 and 20 from above and below via thermal compensation plates 16a and 16b.

[0027] A gate pin 180 is in contact with the gate pad electrode 100g (see Figure 2) of the semiconductor element 100 via a tip guide 140 of the resin frame 14. For example, this gate pin 180 is connected to a gate circuit for driving and controlling the semiconductor element 100, and the gate circuit is further connected to a second pad electrode 100b (see Figure 3).

[0028] Figure 5 is a cross-sectional view of BB' in Figure 4. Figure 6 is a cross-sectional view of CC' in Figure 4. As shown in Figures 5 and 6, the frame 102 is a structural part that extends from the end of the semiconductor element 100 inward towards the first electrode surface. In the following description, the second structural part 104a may be used as an example, but the second structural parts 104b to d have a structure equivalent to that of the second structural part 104a.

[0029] The frame 102 has a first surface 200 and a second surface 202, the surfaces facing the first electrode surface having at least two different gradients relative to the first electrode surface. That is, the first structural part 103 is a structural part having the first surface 200. The second structural parts 104a to d are structural parts having the second surface 202. Note that surfaces having gradients are sometimes referred to as tapered surfaces.

[0030] The first surface 200 on the end side of the semiconductor element 100 is configured to surround the outer periphery of the semiconductor element 100. This first surface 200 has a gradient that moves away from the first electrode surface as it moves inward from the end of the semiconductor element 100 toward the first electrode surface.

[0031] An adhesive 300 is formed between the first surface 200 and the first electrode surface of the semiconductor element 100. The adhesive 300 is formed of a resin material that has good adhesion to both the frame 102 and the semiconductor element 100, for example. The adhesive 300 is formed of a resin material that has good adhesion to metals, such as silicon resin.

[0032] As shown in Figure 6, there is a step between the second surface 202, which is inside the first electrode surface, and the first surface 200, which is inside the first electrode surface, of the two surfaces 200 and 202 having different gradients. This second surface 202 has a gradient that moves away from the first electrode surface as it moves inward from the edge of the semiconductor element 100 towards the first electrode surface.

[0033] The gradient of the second surface 202 relative to the first electrode surface is set to be stronger than, for example, the gradient of the first surface 200 relative to the first electrode surface. That is, if the distance from the edge of the semiconductor element 100 toward the interior is the same, the increase in the distance between the second surface 202 and the first electrode surface will be greater than the increase in the distance between the first surface 200 and the first electrode surface.

[0034] Referring again to Figure 2, the frame 102 is configured such that the second structural parts 104a to d, which have a gradient on the second surface 202, are convex inward toward the first electrode surface. The inner end faces 202b (see Figure 6) of the second structural parts 104a to d toward the first electrode surface are located further inward toward the first electrode surface than the inner end face 202a (see Figure 5) of the first structural part 103 which does not constitute the second structural parts 104a to d.

[0035] More specifically, the first electrode surface of the semiconductor element 100 has at least two opposing sides, and the frame 102 constitutes second structural parts 104a to d for each opposing side. As a result, the frame 102 restricts the range of movement of the first thermal compensation plate 16a along the first electrode surface at the inner end faces 202b of the first electrode surface in the second structural parts 104a to d. That is, the range of movement of the first thermal compensation plate 16a along the first electrode surface is restricted at the inner ends of the first electrode surface in the second structural parts 104a to d.

[0036] Thus, the area between the first surface 200 and the first electrode surface of the semiconductor element 100 becomes the region constituting the adhesive 300. On the other hand, the second structural parts 104a to 104d are used to position the first thermal compensation plate 16a at the desired position on the first electrode surface of the semiconductor element 100.

[0037] Here, the technical effects of the first surface 200 and the second surface 202 will be explained with reference to Figure 7. Figure 7 is a cross-sectional view of frame 102a in a comparative example.

[0038] In the comparative example, frame 102a has an opposing surface 200a parallel to the first electrode surface of the semiconductor element 100. The end surface 204a on the inside of the first electrode surface of frame 102a is used for aligning the first heat compensation plate 160a. Adhesive 300a is formed between the opposing surface 200a and the first electrode surface of the semiconductor element 100. Thus, in the frame 102a of the comparative example, the opposing surface 200a is formed around the semiconductor element 100 with the same width. In addition, aluminum material 302 is formed on the first electrode surface of the semiconductor element 100.

[0039] Adhesive 300a may seep out from between the opposing surface 200a of the frame 102a and the first electrode surface. In this case, since the end surface 204a is used for aligning the first thermal compensation plate 160a, a so-called compressed region 304a may be created by the first thermal compensation plate 160a. Because high pressure is applied to the first thermal compensation plate 160a, the compressed region 304a spreads along the first electrode surface of the semiconductor element 100. As a result, the adhesion between the semiconductor element 100 and the thermal compensation plate 160a deteriorates, resulting in an uneven pressure contact state. Consequently, the contact electrical resistance between the semiconductor element 100 and the thermal compensation plate 160a increases, making it more susceptible to failure due to current imbalance.

[0040] In contrast, in the frame 102 according to this embodiment, the second structural parts 104a to d are aligned at their end faces 202b (see Figure 6). For example, as shown in Figure 7, the first heat compensation plate 16a is positioned at a distance from the end face 202a (see Figure 5) of the frame 102, so that even if the adhesive 300 seeps out from the first surface 200, the possibility of a stepped area being created is reduced.

[0041] In this case, the first surface 200 has a slope in which the distance from the first electrode surface increases as it moves inward from the edge of the semiconductor element 100. For this reason, the thickness of the adhesive 300 is also made thicker as it moves inward from the edge of the semiconductor element 100. This promotes adhesion in the opening direction and suppresses leakage to the back surface.

[0042] Furthermore, by forming a second surface 202, the creepage distance to surface 202b is increased, suppressing the flow of the adhesive onto surface 202b.

[0043] Referring again to Figure 4, by configuring the second structural parts 104a to d in a part of the frame 102, a gap is created between the first heat compensation plate 16a and the end face 202a (see Figure 5). This makes it easy to visually check the state of leakage of the adhesive 300.

[0044] As described above, the frame 102 is configured to have a first structural part 103 that extends inward from the end of the semiconductor element 100 toward the first electrode surface, with a first surface 200 facing the first electrode surface having a first gradient with respect to the first electrode surface, and second structural parts 104a to d that extend further inward from the first structural part 103 toward the first electrode surface, with a second surface 202 facing the first electrode surface. This makes it possible to configure the end faces 202b of the second structural parts 104a to d toward the inside of the first electrode surface than the end of the first surface 200 when the adhesive 300 is formed between the first surface 200 and the first electrode surface. As a result, the gap between the adhesive 300 and the first heat compensation plate 16a is separated by the second structural parts 104a to d, so that even if the adhesive 300 seeps out from between the first surface 200 and the first electrode surface, it is prevented from being pressed against the first heat compensation plate 16a.

[0045] (Modification 1 of the first embodiment) The semiconductor device 1 according to Modification 1 of the First Embodiment differs from the semiconductor device 1 according to the First Embodiment in that it also forms a gradient in the lateral direction of the second structural parts 104a to d. The differences from the semiconductor device 1 according to the First Embodiment will be explained below.

[0046] Figure 8 shows a side view of the second structural part 104a. Figure 8(a) is the same as Figure 6. Figure 8(b) is a front view of the second structural part 104a with the first heat compensation plate 16a viewed through it.

[0047] As shown in Figure 8(b), the width in the direction along the first electrode surface of the semiconductor element 100 and perpendicular to the direction from the edge of the semiconductor element 100 toward the interior (x-direction) increases as it moves away from the first electrode surface. That is, the width (x-direction) of the first surface 200 of the convex second structure 104a is smaller than the width (x-direction) of the terminal portion of the second surface 202.

[0048] As explained above, a gradient is also formed in the lateral direction (x direction) of the convex-shaped second structural parts 104a to d. This improves the visibility of the second structural parts 104a to d and simplifies the alignment of the first heat compensation plate 16a.

[0049] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0050] 1: Semiconductor device, 10: Semiconductor chip, 12: Housing, 14: Resin frame, 16a: First thermal compensation plate, 16b: Second thermal compensation plate, 18: First electrode block, 20: Second electrode block, 100: Semiconductor element, 102: Frame, 103: 1st: First structural part, 104a~d: Second structural part, 200: First surface, 202: Second surface, 300: Adhesive, 202a: End surface, 202b: End surface

Claims

1. A semiconductor element having a first electrode surface and a second electrode surface facing the first electrode surface, The semiconductor element comprises a frame formed around the semiconductor element and having an opening relative to the first electrode surface, The aforementioned frame is A first structural portion extending from the end of the semiconductor element toward the inside of the first electrode surface, the first structural portion having a first surface facing the first electrode surface, A semiconductor device comprising: a second structural portion extending further inward from the first structural portion towards the first electrode surface, the second structural portion having a second surface different from the first surface facing the first electrode surface.

2. The semiconductor device according to claim 1, wherein the first surface has a gradient that moves away from the first electrode surface as it moves inward from the edge of the semiconductor element toward the first electrode surface.

3. The semiconductor device according to claim 2, wherein the second surface has a gradient that moves away from the first electrode surface as it moves inward from the end of the semiconductor element toward the first electrode surface.

4. The semiconductor device according to claim 3, wherein the gradient of the second surface with respect to the first electrode surface is stronger than the gradient of the first surface with respect to the first electrode surface.

5. The semiconductor device according to any one of claims 1 to 4, wherein the first surface of the first structural part is configured to surround the outer periphery of the semiconductor element.

6. The semiconductor device according to claim 5, wherein the first surface and the second surface have a step between them.

7. The semiconductor device according to claim 6, further comprising an adhesive formed between the first surface and the first electrode surface.

8. The system further comprises a first thermal compensation plate that is pressed against the first electrode surface, The semiconductor device according to claim 7, wherein the inner end of the second structural part of the first electrode surface restricts the range of movement of the first thermal compensation plate along the first electrode surface.

9. The first electrode surface has at least two opposing sides, The semiconductor device according to claim 8, wherein the second structural part is configured in a convex shape on each of the opposing sides.

10. The semiconductor device according to claim 9, wherein the width of the convex shape in the direction along the edge increases as it moves away from the first electrode surface.

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