Semiconductor equipment
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KK TOSHIBA
- Filing Date
- 2023-03-15
- Publication Date
- 2026-08-04
Smart Images
Figure 0007900318000001 
Figure 0007900318000002 
Figure 0007900318000003
Abstract
Description
Technical Field
[0001] The embodiment relates to a semiconductor device.
Background Art
[0002] For semiconductor devices for power control, reduction of conduction loss and improvement of heat dissipation are required.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The embodiment provides a semiconductor device with reduced conduction loss and improved heat dissipation.
Means for Solving the Problems
[0005] The semiconductor device according to the embodiment includes a metal base, a terminal spaced apart from the metal base, a semiconductor chip, a connection member, and a conductive member. The semiconductor chip has a back - side electrode connected to the metal base and a front - side electrode provided on a surface opposite to the back - side electrode. The connection member has a first end connected to the front - side electrode of the semiconductor chip and a second end connected to the terminal. The conductive member is provided on the front - side electrode of the semiconductor chip and covers a region not connected to the first end of the connection member of the front - side electrode.
Brief Description of the Drawings
[0006] [Figure 1] It is a schematic diagram showing a semiconductor device according to the first embodiment. [Figure 2] It is a schematic cross - sectional view showing a semiconductor chip according to the first embodiment. [Figure 3] This is a schematic plan view showing the manufacturing process of a semiconductor device according to the first embodiment. [Figure 4] This is a schematic plan view showing a semiconductor chip according to the first embodiment. [Figure 5] This is a schematic diagram showing a semiconductor device according to the second embodiment. [Modes for carrying out the invention]
[0007] The embodiments will be described below with reference to the drawings. Identical parts in the drawings will be numbered the same, and detailed explanations of those parts will be omitted as appropriate, while different parts will be described. Note that the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of sizes between parts, etc., are not necessarily the same as in reality. Furthermore, even when representing the same part, the dimensions and ratios may be depicted differently in different drawings.
[0008] Furthermore, the arrangement and configuration of each part will be explained using the X, Y, and Z axes shown in each figure. The X, Y, and Z axes are mutually orthogonal and represent the X, Y, and Z directions, respectively. In some cases, the Z direction is described as upward and the opposite direction as downward.
[0009] (First Embodiment) Figures 1(a) and 1(b) are schematic diagrams showing a semiconductor device 1 according to the first embodiment. Figure 1(a) is a plan view, and Figure 1(b) is a cross-sectional view along line AA shown in Figure 1(a).
[0010] As shown in Figure 1(a), the semiconductor device 1 includes a semiconductor chip 10, a metal base 20, a first terminal 30, a second terminal 40, a first connecting member 50, and a second connecting member 60. The semiconductor chip 10 is a power semiconductor such as a MOS transistor, an IGBT (Insulated Gate Bipolar Transistor), or a diode. In the following example, the semiconductor chip 10 is a MOS transistor.
[0011] The semiconductor chip 10 is mounted on a metal base 20. The metal base 20 is a metal plate containing, for example, copper or aluminum. The semiconductor chip 10 includes a surface electrode 11 provided on the surface opposite to the back surface connected to the metal base 20, and a control pad 13. The control pad 13 is provided on the surface side of the semiconductor chip 10, spaced apart from the surface electrode 11.
[0012] The first terminal 30 and the metal base 20 are arranged side by side in the Y direction, for example. The second terminal 40 and the metal base 20 are also arranged side by side in the Y direction. The first terminal 30 and the second terminal 40 are arranged side by side in the X direction, for example. The first terminal 30, the second terminal 40 and the metal base 20 are arranged spaced apart from each other. The first terminal 30 and the second terminal 40 are made of the same material as the metal base 20, for example.
[0013] The first connecting member 50 electrically connects the surface electrode 11 of the semiconductor chip 10 to the first terminal 30. The first connecting member 50 is a so-called metal connector and includes copper or aluminum. The first terminal 30 is, for example, a source terminal.
[0014] The second connecting member 60 electrically connects the control pad 13 of the semiconductor chip 10 to the second terminal 40. The second connecting member 60 is a so-called metal connector and includes copper or aluminum. The second terminal 40 is, for example, a gate terminal.
[0015] The semiconductor device 1 further comprises a conductive member 70. The conductive member 70 is provided on the surface electrode 11 of the semiconductor chip 10. The conductive member 70 covers the area of the surface electrode 11 that is not connected to the first connecting member 50.
[0016] Preferably, the conductive member 70 is provided to cover substantially the entire area of the surface electrode 11 that is not connected to the first connecting member 50. The first connecting member 50 has, for example, a first width W1 in the X direction. The conductive member 70 has, for example, a second width W2 in the X direction that is wider than the first width W1.
[0017] As shown in FIG. 1(b), the semiconductor chip 10 is mounted on the metal base 20 via the joining member 21. The joining member 21 is, for example, a solder material. The semiconductor chip 10 is electrically connected to the metal base 20 via the joining member 21. The metal base 20 is, for example, a drain terminal.
[0018] The first connection member 50 has a first end portion 50E1 connected to the semiconductor chip 10 and a second end portion 50E2 connected to the first terminal 30. The first end portion 50E1 is connected to the surface-side electrode 11 of the semiconductor chip 10 via the joining member 53. The second end portion 50E2 is connected to the first terminal 30 via the joining member 55. The joining members 53 and 55 are, for example, solder materials.
[0019] The conductive member 70 has a first thickness T1 in a direction perpendicular to the surface of the semiconductor chip 10, for example, the Z direction. The first connection member 50 has, for example, a second thickness T2 in the Z direction. Further, the first connection member 50 has a back surface 50B connected to the semiconductor chip 10, an upper surface 50T opposite to the back surface 50B, and a side surface 50S connected to the back surface 50B and the upper surface 50T.
[0020] The conductive member 70 is provided so as to contact at least the side surface 50S of the first end portion 50E1, and may be provided so as to cover the upper surface 50T of the first end portion 50E1 of the first connection member 50. In this example, the first thickness T1 of the conductive member 70 in the Z direction is described as being thicker than the second thickness T2 of the first connection member 50 in the Z direction. However, even when the first thickness T1 is thinner than the second thickness T2, the conductive member 70 may be provided so as to cover the upper surface 50T of the first end portion 50E1 of the first connection member 50. That is, regardless of the thickness in the Z direction, the conductive member 70 may be provided so as to cover at least a part of the upper surface 50T at the first end portion 50E1. Thus, the conductive member 70 contacts the first connection member 50 and is electrically connected. The conductive member 70 is, for example, a solder material. Also, the conductive member 70 may be a metal paste such as a silver paste or a copper paste. Further, the conductive member 70 may be a conductive resin such as a conductive adhesive, a conductive silicone, or a conductive coating agent. When the conductive member 70 is a paste or a conductive resin member, it is preferable that the first thickness T1 is thicker than the second thickness T2 of the first connection member 50.
[0021] The conductive member 70 may be made of the same material as the joining member 53 or a different material. When the material of the conductive member 70 and the material of the joining member 53 are the same, the affinity between the conductive member 70 and the joining member 53 is improved, and the joining strength is increased. Also, when the material of the conductive member 70 and the material of the joining member 53 are different, it becomes easy to avoid the movement of the first connection member 50 due to the re-melting of the joining member 53 when forming the conductive member 70.
[0022] The semiconductor device 1 further includes a sealing resin 80. The sealing resin 80 covers an assembly including the semiconductor chip 10, the metal base 20, the first terminal 30, the second terminal 40, the first connection member 50, and the second connection member 60. The sealing resin 80 seals the semiconductor chip 10 on the metal base 20. The sealing resin 80 is, for example, an epoxy resin or a polyimide.
[0023] In the semiconductor device 1 according to this embodiment, by providing a conductive member 70 on the surface electrode 11 of the semiconductor chip 10, the electrical resistance in the current path from the semiconductor chip 10 to the first connecting member 50 can be reduced. This reduces the on-resistance and thus the conduction loss. Furthermore, it is also possible to improve heat dissipation by transferring the Joule heat generated in the semiconductor chip 10 to the first connecting member 50 via the conductive member 70.
[0024] Furthermore, by providing a conductive member 70 on the surface electrode 11 of the semiconductor chip 10, it is possible to reduce the connection area between the first connecting member 50 and the surface electrode 11 without reducing on-resistance and thermal conductivity. For example, if the conductive member 70 is not provided, it is desirable to change the size of the first connecting member 50 to match the size of the semiconductor chip 10 mounted on the metal base 20. This is desirable to increase the connection area between the first connecting member 50 and the surface electrode 11 and improve on-resistance and thermal conductivity. In contrast, in the semiconductor device 1 according to this embodiment, it is not necessary to adjust the size of the first connecting member 10 to match the size of the semiconductor chip 10, thus simplifying the manufacturing process and reducing costs.
[0025] Figure 2 is a schematic cross-sectional view illustrating a semiconductor chip 10 according to the first embodiment. The semiconductor chip 10 includes a front electrode 11, a semiconductor portion 15, a back electrode 17, and a gate electrode 18.
[0026] The front electrode 11 is, for example, a source electrode. The back electrode 17 is, for example, a drain electrode. The back electrode 17 is provided on the back surface of the semiconductor portion 15 and is connected to the metal base 20 via a bonding member 21. The front electrode 11 is provided on the surface of the semiconductor portion 15 opposite to the back surface.
[0027] The gate electrode 18 is provided on the surface side of the semiconductor portion 15 and has, for example, a trench gate structure. The gate electrode 18 is electrically insulated from the semiconductor portion 15 by a gate insulating film 19. The gate electrode 18 is electrically connected to the control pad 13 (see Figure 1(a)).
[0028] The semiconductor portion 15 includes, for example, an n-type drift layer 23, a p-type body layer 25, an n-type source layer 27, and a p-type contact layer 29. The n-type drift layer 23 extends between the front electrode 11 and the back electrode 17. The p-type body layer 25 is provided between the n-type drift layer 23 and the front electrode 11 and is located between adjacent gate electrodes 18 in the Y direction.
[0029] The n-type source layer 27 is provided between the surface electrode 11 and the p-type body layer 25. Similarly, the p-type contact layer 29 is also provided between the surface electrode 11 and the p-type body layer 25. The n-type source layer 27 and the p-type contact layer 29 are arranged, for example, along the surface of the semiconductor portion 15 and connected to the surface electrode 11.
[0030] The surface electrode 11 has, for example, a third thickness T3 in the Z direction. The outer edge of the surface electrode 11 is covered by, for example, a resin member 85. The resin member 85 is, for example, polyimide. The surface electrode 11 is connected to the first end 50E1 of the first connecting member 50 in the portion exposed inside the resin member 85. The conductive member 70 is provided to cover the inside of the resin member 85. Preferably, the conductive member 70 covers most of the region of the surface electrode 11 that is exposed inside the resin member 85 and not connected to the first end 50E1.
[0031] For example, increasing the third thickness T3 of the surface electrode 11 reduces surface resistance and improves thermal conductivity. However, increasing the third thickness T3 is not always easy. Increasing the third thickness T3 can increase internal stress in the semiconductor chip 10, for example, which may reduce manufacturing yield.
[0032] In contrast, in the semiconductor device 1 according to this embodiment, it is not necessary to use a semiconductor chip with a thicker third thickness T3. For example, by providing a conductive member 70 having a first thickness T1 that is thicker than the third thickness T3, the surface resistance of the surface electrode 11 can be reduced and thermal conductivity can be improved. In other words, by making the thickness T3 of the surface electrode 11 thinner, the manufacturing of the semiconductor chip 10 becomes easier, and the cost of the semiconductor chip 10 can be reduced.
[0033] Figures 3(a) and 3(b) are schematic plan views showing the manufacturing process of the semiconductor device 1 according to the first embodiment. Figures 3(a) and 3(b) show the upper surface of the metal base 20.
[0034] As shown in Figure 3(a), after mounting the semiconductor chip 10 onto the metal base 20, bonding members 53 and 55 are applied to the surface electrodes 11 and first terminals 30 of the semiconductor chip 10, respectively. Bonding members 63 and 65 are also applied to the control pads 13 and second terminals 40 of the semiconductor chip 10, respectively. Bonding members 53, 55, 63, and 65 are, for example, solder paste.
[0035] A resin member 87 is provided on the surface electrode 11 of the semiconductor chip 10. The resin member 87 is positioned at the boundary between the region of the surface electrode 11 connected to the first connecting member 50 and the region not connected to the first connecting member 50. The resin member 87 is provided in a size that allows its influence on electrical and thermal conduction between the surface electrode 11 and the conductive member 70 (see Figure 1) to be negligible. The resin member 87 is, for example, polyimide. Note that the resin member 87 is provided as needed, and a configuration without the resin member 87 is also possible.
[0036] As shown in Figure 3(b), the first connecting member 50 is placed on the surface electrode 11 and the first terminal 30 and pressed from above. As a result, the first connecting member 50 is connected to the surface electrode 11 of the semiconductor chip 10 via the bonding member 53 and to the first terminal 30 via the bonding member 55. Similarly, the second connecting member 60 is connected to the control pad 13 of the semiconductor chip 10 via the bonding member 63 and to the second terminal 40 via the bonding member 65.
[0037] Next, the assembly, which includes the semiconductor chip 10, the metal base 20, the first terminal 30, the second terminal 40, the first connecting member 50, and the second connecting member 60, is placed inside a reflow oven, for example, and heated. After that, the assembly is removed from the reflow oven and cooled. This hardens the bonding members 53 and 55, and the first connecting member 50 is fixed onto the surface electrode 11 and the first terminal 30 of the semiconductor chip 10. Similarly, the second connecting member 60 is fixed onto the control pad 13 and the second terminal 40 of the semiconductor chip 10.
[0038] Furthermore, the conductive material 70 (see Figure 1) is applied to the surface electrode 11 of the semiconductor chip 10 and cured. If the conductive material 70 is solder, after applying the conductive material 70, the assembly is heated again in a reflow oven, removed from the reflow oven, and cooled.
[0039] During this process, the bonding member 53 may melt and spread to areas of the surface electrode that are not connected to the first connecting member 50, and the first connecting member 50 may move to an unintended position. The resin member 87 prevents the melted bonding member 53 from spreading and suppresses the movement of the first connecting member 50.
[0040] Figures 4(a) to 4(c) are schematic plan views showing a semiconductor chip 10 according to the first embodiment. Figures 4(a) to 4(c) show the surface side of the semiconductor chip 10.
[0041] As shown in Figures 4(a) to 4(c), a plurality of resin members 87 are provided on the surface electrode 11. The resin members 87 are spaced apart from each other and arranged in a direction along one side of the semiconductor chip 10, for example, in the X direction. The planar shape of the resin members 87 may be triangular, trapezoidal, or circular. In other words, the resin members 87 have any planar shape.
[0042] (Second Embodiment) Figures 5(a) and 5(b) are schematic diagrams showing a semiconductor device 2 according to the second embodiment. Figure 5(a) is a plan view. Figure 5(b) is a cross-sectional view along line BB shown in Figure 5(a).
[0043] As shown in Figure 5(a), the semiconductor device 2 includes a semiconductor chip 10, a metal base 20, a first terminal 30, and a second terminal 40. The semiconductor chip 10 is mounted on the metal base 20.
[0044] The metal base 20, the first terminal 30, and the second terminal 40 are arranged spaced apart from each other. The first terminal 30 is electrically connected to the surface electrode 11 of the semiconductor chip 10, for example, via a plurality of metal wires 90. The second terminal 40 is electrically connected to the control pad 13 of the semiconductor chip 10, for example, via a metal wire 95. The metal wires 90 and 95 are, for example, copper wires or aluminum wires.
[0045] A conductive member 70 is provided on the surface electrode 11 of the semiconductor chip 10. Preferably, the conductive member 70 covers the metal wire 90. The conductive member 70 is provided, for example, to cover most of the surface electrode 11. Preferably, the conductive member 70 covers the entire surface electrode 11, excluding the outer edge which is covered by the resin member 85.
[0046] As shown in Figure 5(b), the semiconductor chip 10 is connected to the metal base 20 via a bonding member 21. The metal wire 90 has a first end 90E1 connected to the semiconductor chip 10 and a second end 90E2 connected to the first terminal 30. The conductive member 70 covers the first end 90E1 of the metal wire 90.
[0047] An assembly comprising a semiconductor chip 10, a metal base 20, a first terminal 30, and a second terminal 40 is sealed in a sealing resin 80. Parts of the metal base 20, the first terminal 30, and the second terminal 40 extend from the sealing resin 80.
[0048] In this example as well, by providing a conductive member 70 on the surface electrode 11 of the semiconductor chip 10, surface resistance can be reduced and thermal conductivity can be improved. For example, if a conductive member 70 is not provided on the surface electrode 11, the metal wire 90 will contact the surface electrode 11 at the bottom surface of its first end 90E1. Therefore, the contact area between the surface electrode 11 and the metal wire 90 is limited. Even if the number of metal wires 90 is increased to widen the contact area, the number of metal wires 90 that can be connected to the surface electrode 11 is limited. In contrast, in the semiconductor device 2 according to this embodiment, by providing a conductive member 70 on the surface electrode 11, it becomes possible to electrically connect the entire surface of the first end 90E1 of the metal wire 90 to the surface electrode 11. This reduces on-resistance and improves thermal conductivity through the metal wire 90.
[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.
[0050] (Note 1) Metal base and A terminal spaced apart from the aforementioned metal base, A semiconductor chip having a back-side electrode connected to the metal base and a front-side electrode provided on the surface opposite to the back-side electrode, A connecting member having a first end connected to the surface electrode of the semiconductor chip and a second end connected to the terminal, A conductive member provided on the surface electrode of the semiconductor chip, covering a region on the surface electrode that is not connected to the first end of the connecting member, A semiconductor device equipped with the following features. (Note 2) The conductive member covers at least partially the first end of the connecting member, as described in Appendix 1, the semiconductor device. (Note 3) The connecting member has a back surface that is connected to the front electrode and a front surface opposite to the back surface. The conductive member partially covers the surface at the first end of the connecting member, as described in Appendix 1, in the semiconductor device described in Appendix 1. (Note 4) A semiconductor device according to any one of the appendices 1 to 3, wherein the thickness of the conductive member in a direction perpendicular to the surface of the semiconductor chip is greater than the thickness of the surface electrode. (Note 5) The semiconductor device according to any one of the appendices 1 to 4, wherein the thickness of the conductive member in a direction perpendicular to the surface of the semiconductor chip is greater than the thickness of the connecting member. (Note 6) The system further comprises a joining member provided between the first end of the connecting member and the surface electrode, The semiconductor device according to any one of the appendices 1 to 5, wherein the bonding member includes a material different from the material of the conductive member. (Note 7) The system further comprises a joining member provided between the first end of the connecting member and the surface electrode, The semiconductor device according to any one of the appendices 1 to 6, wherein the bonding member contains the same material as the conductive member. (Note 8) The semiconductor device according to any one of appendices 1 to 7, further comprising a resin member provided at the boundary between a region connected to the first end of the connecting member and a region not connected to the first end of the surface electrode. (Note 9) The metal base and the terminal are aligned in a first direction. In a second direction along the surface electrode, which is perpendicular to the first direction, the connecting member has a first width. The semiconductor device according to any one of appendices 1 to 8, wherein the conductive member has a second width in the second direction, and the first width is narrower than the second width. (Note 10) The connecting member is a plate-shaped metal connector, having a back surface connected to the surface electrode, a front surface opposite to the back surface, and side surfaces connected to the back surface and the front surface. The semiconductor device according to Appendix 1 or 2, wherein the conductive member is provided at the first end so as to be in contact with at least the side surface. (Note 11) The connecting member is a metal wire, The conductive member covers the surface electrode and is in contact with the first end of the metal wire, as described in any one of the appendices 1 to 9, in the semiconductor device. (Note 12) The connecting member is a metal wire, The conductive member covers the surface electrode and the first end of the metal wire, as described in any one of the appendices 1 to 9. [Explanation of symbols]
[0051] 1, 2…Semiconductor device, 10…Semiconductor chip, 11…Surface electrode, 13…Control pad, 15…Semiconductor part, 17…Backside electrode, 18…Gate electrode, 19…Gate insulating film, 20…Metal base, 21, 53, 55, 63, 65…Bonding member, 23…n-type drift layer, 25…p-type body layer, 27…n-type source layer, 29…p-type contact layer, 30…First terminal, 40…Second terminal, 50…First connecting member, 50B…Backside, 50S…Side, 50T…Top, 60…Second connecting member, 70…Conductive member, 80…Sealing resin, 85, 87…Resin member, 90, 95…Metal wire
Claims
1. Metal base and A terminal spaced apart from the aforementioned metal base, A semiconductor chip having a back-side electrode connected to the metal base and a front-side electrode provided on the surface opposite to the back-side electrode, A connecting member having a first end connected to the surface electrode of the semiconductor chip and a second end connected to the terminal, A conductive member provided on the surface electrode of the semiconductor chip, covering a region of the surface electrode that is not connected to the first end of the connecting member, A joining member is provided between the first end of the connecting member and the surface electrode, Equipped with, A semiconductor device wherein the bonding member contains a material different from the material of the conductive member.
2. Metal base and A terminal spaced apart from the aforementioned metal base, A semiconductor chip having a back-side electrode connected to the metal base and a front-side electrode provided on the surface opposite to the back-side electrode, A connecting member having a first end connected to the surface electrode of the semiconductor chip and a second end connected to the terminal, A conductive member provided on the surface electrode of the semiconductor chip, covering a region of the surface electrode that is not connected to the first end of the connecting member, In the surface electrode, a resin member is provided at the boundary between the region connected to the first end of the connecting member and the region not connected to the first end. A semiconductor device equipped with the following features.
3. The semiconductor device according to claim 1 or 2, wherein the conductive member covers at least partially the first end of the connecting member.
4. The connecting member has a back surface that is connected to the front electrode and a front surface opposite to the back surface. The semiconductor device according to claim 1 or 2, wherein the conductive member partially covers the surface at the first end of the connecting member.
5. The semiconductor device according to claim 1 or 2, wherein the thickness of the conductive member in a direction perpendicular to the surface of the semiconductor chip is greater than the thickness of the surface electrode.
6. The semiconductor device according to claim 1 or 2, wherein the thickness of the conductive member in a direction perpendicular to the surface of the semiconductor chip is greater than the thickness of the connecting member.
7. The metal base and the terminal are aligned in the first direction, In a second direction along the surface electrode, which is perpendicular to the first direction, the connecting member has a first width. The semiconductor device according to claim 1 or 2, wherein the conductive member has a second width in the second direction, and the first width is narrower than the second width.
8. The connecting member is a plate-shaped metal connector, having a back surface connected to the surface electrode, a front surface opposite to the back surface, and side surfaces connected to the back surface and the front surface. The semiconductor device according to claim 1 or 2, wherein the conductive member is provided at the first end so as to be in contact with at least the side surface.
9. The connecting member is a metal wire, The semiconductor device according to claim 1 or 2, wherein the conductive member covers the surface electrode and is in contact with the first end of the metal wire.
10. The connecting member is a metal wire, The semiconductor device according to claim 1 or 2, wherein the conductive member covers the surface electrode and the first end of the metal wire.