Substrate-free direct-cooling power module

Abstract

The invention discloses a substrate-free direct-cooling power module, which comprises a conductor radiator, the top surface of which is a mounting surface; the power chip is arranged on the mounting surface of the conductor radiator, a drain electrode is arranged on the bottom surface of the power chip, a source electrode and a gate electrode are respectively arranged at two ends of the top surface of the power chip, and the drain electrode of the power chip is connected with the mounting surface of the conductor radiator through a first welding layer; the drain electrode leading-out structure is connected with the conductor radiator and is used for electrically leading out a drain electrode; the source electrode leading-out structure is connected with the source electrode and is used for electrically leading out the source electrode; the grid leading-out structure is connected with the grid electrode and is used for electrically leading out the grid electrode; and the plastic package body wraps the power chip, the drain electrode lead-out structure, the source electrode lead-out structure, the grid electrode lead-out structure and the conductor radiator. The heat resistance of the power module can be reduced, the heat dissipation efficiency is improved, and the parasitic inductance and resistance of the module are reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, and more particularly to a substrate-free direct-cooling power module. Background Art

[0002] In traditional SiC MOSFET power modules, the bottom surface of the MOSFET chip is welded to the copper-clad side of the DBC (Direct Bond Copper) or AMB (Active Metal Brazing) substrate, and the copper-clad DBC or AMB is used to conduct current; the other side of the DBC or AMB substrate is connected to the heat sink through the thermal interface material (TIM), and the chip heat power needs to pass through the DBC or AMB substrate, and then pass through the TIM to the heat sink for dissipation. In order to reduce the thermal resistance of the module, domestic and foreign scholars and manufacturers have conducted many studies on improving the thermal conductivity of the DBC or AMB substrate ceramic layer and TIM, but the thermal resistance of DBC / AMB and TIM still accounts for a considerable part of the total thermal resistance of the module. Summary of the invention

[0003] The purpose of the present invention is to provide a substrate-free direct-cooling power module, so as to reduce the thermal resistance of the power module, improve the heat dissipation efficiency, and reduce the parasitic inductance and resistance of the module.

[0004] To achieve the above object, the present invention proposes a substrate-free direct-cooling power module, comprising:

[0005] A conductor heat sink, wherein the top surface of the conductor heat sink is a mounting surface;

[0006] A power chip is arranged on the mounting surface of the conductor heat sink, a drain electrode is arranged on the bottom surface of the power chip, a source electrode and a gate electrode are arranged at two ends of the top surface of the power chip, and the drain electrode of the power chip is connected to the mounting surface of the conductor heat sink through a first solder layer;

[0007] A drain lead-out structure, connected to the conductor heat sink, and used for electrically leading out the drain electrode;

[0008] A source lead-out structure, connected to the source electrode and used for electrical lead-out of the source electrode;

[0009] A gate lead-out structure, connected to the gate electrode and used for electrically leading out the gate electrode;

[0010] The plastic package covers the power chip, the drain lead-out structure, the source lead-out structure, the gate lead-out structure and the conductor heat sink.

[0011] Optionally, the drain electrode is a layered structure covering the bottom surface of the power chip, and the area of ​​the first solder layer is not less than the area of ​​the drain electrode.

[0012] Optionally, the drain lead-out structure includes a drain terminal, a bottom end of the drain terminal is connected to an upper surface of the conductor heat sink, and a top end of the drain terminal is connected to a top surface extending out of the plastic package body.

[0013] Optionally, the source lead-out structure includes a current guide bar and a source terminal;

[0014] The bottom surface of the guide bar is connected to the source electrode through a second welding layer;

[0015] The bottom end of the source terminal is connected to the guide bar, and the top end of the source terminal extends out of the top surface of the plastic package body.

[0016] Optionally, the gate lead-out structure includes a conductive pin, an insulating bracket and a gate terminal;

[0017] The lower surface of one end of the insulating support is connected to the upper surface of the guide bar, and the other end of the insulating support is suspended above the gate electrode;

[0018] The gate terminal is arranged on the insulating support, the bottom end of the gate terminal is connected to the insulating support, and the top end of the gate terminal extends out of the top surface of the plastic package body;

[0019] The bottom end of the conductive pin is connected to the gate electrode, and the top end of the conductive pin passes through the other end of the insulating bracket and is connected to the bottom of the gate terminal.

[0020] Optionally, the power chip includes a SiC MOSFET power semiconductor chip.

[0021] Optionally, the conductor heat sink is made of metal and has a heat dissipation structure.

[0022] Optionally, the heat dissipation structure includes a coolant flow channel structure arranged inside the conductor heat sink.

[0023] Optionally, the material of the first solder layer and the second solder layer includes at least one of gold, silver, copper, aluminum, and tin.

[0024] The beneficial effects of the present invention are:

[0025] Compared with the existing power module structure of connecting the power chip to the heat sink through the substrate and TIM, the substrate-free direct-cooling power module of the present invention adopts a structural design of directly connecting the drain electrode on the bottom surface of the power chip to the mounting surface of the conductor heat sink through the first welding layer, eliminating the substrate and TIM of the traditional power module, which can directly suppress the thermal resistance introduced by this part. Compared with the traditional power module with a substrate, it can significantly reduce the overall thermal resistance of the power module and improve the heat dissipation efficiency; at the same time, the drain lead-out structure of the power module of the present application is connected to the drain of the power chip through a conductor heat sink, and the conductor heat sink is used to directly participate in the conduction and guide the drain current. Its conduction area is much larger than the traditional DBC or AMB substrate copper cladding, which can reduce the module parasitic inductance and resistance to a certain extent and improve the performance of the power module.

[0026] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0028] Figure 1 A schematic structural diagram of a substrate-less direct-cooling power module according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] Prior art 1 discloses an aluminum nitride substrate power module, which uses a high thermal conductivity aluminum nitride substrate to prepare the power module and reduce the thermal resistance of the substrate part, but the thermal resistance of the substrate still exists in this solution.

[0030] The present invention proposes a substrate-free direct-cooling power module structure, which completely eliminates the substrate and directly welds the bottom surface electrode of the power chip to the conductor heat sink. Compared with the traditional DBC or AMB structure, the thermal resistance introduced by DBC / AMB and TIM can be reduced, which has important practical value and significance.

[0031] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0032] Example

[0033] like Figure 1 As shown, this embodiment provides a substrate-free direct-cooling power module, including:

[0034] A conductor heat sink 6, the top surface of the conductor heat sink 6 being a mounting surface;

[0035] A power chip 1 is arranged on the mounting surface of a conductor heat sink 6, a drain electrode 2 is arranged on the bottom surface of the power chip 1, a source electrode 3 and a gate electrode 4 are arranged at both ends of the top surface of the power chip 1, and the drain electrode 2 of the power chip 1 is connected to the mounting surface of the conductor heat sink 6 through a first solder layer 5;

[0036] The drain lead-out structure is connected to the conductor heat sink 6 and is used for electrically leading out the drain electrode 2;

[0037] A source lead-out structure, connected to the source electrode 3, for electrically leading out the source electrode 3;

[0038] A gate lead-out structure, connected to the gate electrode 4, for electrically leading out the gate electrode 4;

[0039] The plastic package covers the power chip 1 , the drain lead-out structure, the source lead-out structure, the gate lead-out structure and the conductor heat sink 6 .

[0040] In this embodiment, the drain electrode 2 is a layered structure covering the bottom surface of the power chip 1, and the area of ​​the first solder layer 5 is not less than the area of ​​the drain electrode 2. The material of the first solder layer 5 includes at least one of gold, silver, copper, aluminum, and tin. The top surface of the first solder layer 5 is completely in contact with the bottom surface of the drain electrode 2. The heat of the power chip 1 is directly transferred to the conductor heat sink 6 through the first solder layer 5, thereby greatly improving the heat dissipation efficiency. The first solder layer 5 and the drain electrode 2 can be connected by melt welding or melt bonding.

[0041] In this embodiment, preferably, the drain lead-out structure includes a drain terminal 7, the drain terminal 7 is columnar, the drain terminal 7 is made of metal materials such as copper and aluminum, the bottom end of the drain terminal 7 is connected to the upper surface of the conductor heat sink 6, and the top end of the drain terminal 7 is connected to the top surface extending out of the plastic package. In other embodiments, one end of the drain terminal 7 can also be connected to other positions of the conductor heat sink 6, such as the side of the conductor heat sink 6, according to design requirements, as long as the two are electrically connected, and the other end of the drain terminal 7 is led out from other positions of the plastic package to the outside, such as the side of the plastic package.

[0042] In this embodiment, the source electrode 3 and the gate electrode 4 are also layered structures located on the upper surface of the power chip 1 , and the source electrode 3 and the gate electrode 4 are located in the same layer.

[0043] In this embodiment, the source lead-out structure includes a current guide bar 9 and a source terminal 10;

[0044] The bottom surface of the current guide bar 9 is connected to the source electrode 3 through the second welding layer 8;

[0045] The bottom end of the source terminal 10 is connected to the guide bar 9 , and the top end of the source terminal 10 extends out of the top surface of the plastic package body.

[0046] The guide bar 9 is a metal sheet, and the material can be copper or aluminum, etc. The material of the second welding layer 8 includes at least one of gold, silver, copper, aluminum, and tin. The guide bar 9 and the second welding layer 8 can be connected by melt welding or melt bonding. The source terminal 10 is columnar and made of metal materials such as copper and aluminum. Its bottom end is connected to one end of the guide bar 9, and the other end is led to the top surface of the plastic package. In other embodiments, it can also be led to the side of the plastic package.

[0047] In this embodiment, the gate lead-out structure includes a conductive pin 11, an insulating bracket 12 and a gate terminal 13;

[0048] The lower surface of one end of the insulating bracket 12 is connected to the upper surface of the guide bar 9, and the other end of the insulating bracket 12 is suspended above the gate electrode 4;

[0049] The gate terminal 13 is disposed on the insulating support 12, the bottom end of the gate terminal 13 is connected to the insulating support 12, and the top end of the gate terminal 13 extends out of the top surface of the plastic package;

[0050] The bottom end of the conductive pin 11 is connected to the gate electrode 4 , and the top end of the conductive pin 11 passes through the other end of the insulating bracket 12 and is connected to the bottom of the gate terminal 13 .

[0051] The conductive pin 11 and the gate terminal 13 may be made of metal materials such as copper and aluminum. The conductive pin 11 and the gate terminal 13 are both columnar, and the insulating bracket 12 is layered. The gate terminal 13 is arranged on the insulating bracket 12. The insulating bracket 12 may be formed of insulating materials such as silicon oxide, aluminum oxide, and polyimide. One end of the insulating bracket 12 is fixed on the guide bar 9, and the other end is screwed on the gate electrode 4. It is mainly used to support the conductive pin 11 and the gate terminal 13. The top of the conductive pin 11 is inserted into the insulating bracket 12, penetrates the insulating bracket 12, and is connected to the bottom of the gate terminal 13. The bottom of the conductive pin 11 is connected to the gate electrode 4.

[0052] In this embodiment, the power chip 1 includes a SiC MOSFET (Silicon Carbide Metal Oxide Semiconductor Field Effect Transistor) power semiconductor chip. In other embodiments, the power chip 1 may also be other IGBT power chips 1.

[0053] In this embodiment, the conductor heat sink 6 is made of metal, that is, the conductor heat sink 6 is a conductor as a whole, and the material of the conductor heat sink 6 is preferably copper or aluminum.

[0054] In this embodiment, the conductor radiator 6 has a heat dissipation structure. Optionally, the heat dissipation structure includes a coolant flow channel structure arranged inside the conductor radiator 6, that is, the conductor radiator 6 has a cavity inside, and the cavity is provided with a flow channel structure for circulating coolant, and the conductor radiator 6 is also designed with a coolant inlet and an outlet connected to the flow channel. In other embodiments, a heat dissipation structure with multiple heat sinks can also be used.

[0055] Based on the above, compared with the traditional power module structure using DBC / AMB substrate and TIM, the power module structure of the present invention adopts a substrate-free structure design, and the bottom electrode of the power chip 1 is directly connected to the conductor heat sink 6, which can directly suppress the thermal resistance introduced by the substrate and TIM part in the traditional structure, improve the heat dissipation efficiency and improve the performance of the power module. In addition, the present invention uses a heat sink to directly participate in the conduction and guide the drain current, and its conduction area is much larger than the traditional DBC or AMB substrate, which can reduce the module parasitic inductance and resistance to a certain extent, and further improve the performance of the power module.

[0056] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A substrate-free direct-cooling power module, characterized in that: include: A conductor heat sink, wherein the top surface of the conductor heat sink is a mounting surface; A power chip is arranged on the mounting surface of the conductor heat sink, a drain electrode is arranged on the bottom surface of the power chip, a source electrode and a gate electrode are arranged at two ends of the top surface of the power chip, and the drain electrode of the power chip is connected to the mounting surface of the conductor heat sink through a first solder layer; A drain lead-out structure, connected to the conductor heat sink, and used for electrically leading out the drain electrode; A source lead-out structure, connected to the source electrode and used for electrical lead-out of the source electrode; A gate lead-out structure, connected to the gate electrode and used for electrically leading out the gate electrode; The plastic package covers the power chip, the drain lead-out structure, the source lead-out structure, the gate lead-out structure and the conductor heat sink.

2. The substrate-free direct-cooling power module according to claim 1, characterized in that: The drain electrode is a layered structure covering the bottom surface of the power chip, and the area of ​​the first solder layer is not less than the area of ​​the drain electrode.

3. The substrate-less direct-cooling power module according to claim 1, characterized in that: The drain lead-out structure comprises a drain terminal, the bottom end of the drain terminal is connected to the upper surface of the conductor heat sink, and the top end of the drain terminal is connected to the top surface extending out of the plastic package body.

4. The substrate-less direct-cooling power module according to claim 1, characterized in that: The source lead-out structure includes a current guide bar and a source terminal; The bottom surface of the guide bar is connected to the source electrode through a second welding layer; The bottom end of the source terminal is connected to the guide bar, and the top end of the source terminal extends out of the top surface of the plastic package body.

5. The substrate-less direct-cooling power module according to claim 4, characterized in that: The gate lead-out structure comprises a conductive pin, an insulating bracket and a gate terminal; The lower surface of one end of the insulating support is connected to the upper surface of the guide bar, and the other end of the insulating support is suspended above the gate electrode; The gate terminal is arranged on the insulating support, the bottom end of the gate terminal is connected to the insulating support, and the top end of the gate terminal extends out of the top surface of the plastic package body; The bottom end of the conductive pin is connected to the gate electrode, and the top end of the conductive pin passes through the other end of the insulating bracket and is connected to the bottom of the gate terminal.

6. The substrate-less direct-cooling power module according to claim 1, characterized in that: The power chip includes a SiCMOSFET power semiconductor chip.

7. The substrate-less direct-cooling power module according to claim 1, characterized in that: The conductor heat sink has a heat dissipation structure.

8. The substrate-less direct-cooling power module according to claim 7, characterized in that: The heat dissipation structure includes a coolant flow channel structure arranged inside the conductor heat sink.

9. The substrate-less direct-cooling power module according to claim 3, characterized in that: The material of the first solder layer and the second solder layer includes at least one of gold, silver, copper, aluminum, and tin.

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