IGBT power module

Abstract

The utility model discloses an IGBT (Insulated Gate Bipolar Translator) power module, which comprises an IGBT chip, a connecting structure, a cooling substrate and a packaging structure, wherein the connection structure comprises a first welding layer, a second welding layer and a DBC ceramic chip, two surfaces of the DBC ceramic chip are respectively connected with the first welding layer and the second welding layer, and the first welding layer is connected with the IGBT chip; the cooling substrate is connected with the second welding layer; the packaging structure packages the IGBT chip and the connecting structure on the cooling substrate. Therefore, the structural connection strength between the DBC ceramic chip and the IGBT chip and the cooling substrate which are respectively arranged at the two sides of the DBC ceramic chip is high, and the reliability and durability of the IGBT power module are ensured. On the basis, the IGBT chip can quickly conduct heat to the cooling substrate through the first welding layer, the DBC ceramic chip and the second welding layer, and compared with a heat conduction scheme adopting heat conduction silicone grease, the heat dissipation efficiency and the highest bearable temperature of the IGBT power module are higher.

Description

Technical Field

[0001] The utility model relates to the technical field of power semiconductors, in particular to an IGBT power module. Background Art

[0002] In the power devices of the electric drive ECU (Engine Control Unit), IGBT (Insulated Gate Bipolar Transistor) is used as a power switching device to adjust the current of the motor, thereby controlling the speed and torque of the motor. IGBT is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor), which has the advantages of both the high input impedance of MOSFET and the low on-state voltage drop of GTR.

[0003] The current IGBT power module usually includes a cooling substrate, a DBC ceramic sheet (Direct Bonded Copper) and an IGBT chip. The DBC ceramic sheet has the functions of structural connection, thermal conductivity and insulation. The cooling substrate is connected to one side of the DBC ceramic sheet through thermal grease, and the IGBT chip is connected to the other side of the DBC ceramic sheet through solder paste and packaged. The thermal conductivity of this structure is insufficient and is only suitable for low-voltage, low-power density IGBT platform solutions. The maximum tolerable temperature of the IGBT power module is relatively low. Utility Model Content

[0004] The main purpose of the utility model is to provide an IGBT power module, aiming at improving the heat dissipation performance.

[0005] To achieve the above object, the utility model provides an IGBT power module, comprising:

[0006] IGBT chip;

[0007] A connection structure, comprising a first welding layer, a second welding layer and a DBC ceramic sheet, wherein two sides of the DBC ceramic sheet are respectively connected to the first welding layer and the second welding layer, and the first welding layer is connected to the IGBT chip;

[0008] a cooling substrate connected to the second welding layer; and

[0009] Packaging structure; the packaging structure packages the IGBT chip and the connection structure on the cooling substrate.

[0010] In some embodiments of the present invention, the first welding layer is tin sheet, silver-based solder or copper-based solder.

[0011] In some embodiments of the present invention, the second welding layer is tin sheet, silver-based solder or copper-based solder.

[0012] In some embodiments of the present invention, the DBC ceramic sheet has a ceramic layer and a first copper layer and a second copper layer respectively connected to both sides of the ceramic layer, the first copper layer is connected to the first welding layer, the second copper layer is connected to the second welding layer, the second welding layer is a copper-tin alloy tin sheet, and the cooling substrate is made of copper.

[0013] In some embodiments of the present invention, the first copper layer includes an electrical connection part and a welding part, the IGBT chip is connected to the electrical connection part via a metal bonding wire, the IGBT chip is welded to the welding part, the first copper layer is connected to the first welding layer, and the first welding layer is a lead-tin alloy tin sheet.

[0014] In some embodiments of the present invention, the welding portion and the first welding layer have the same shape and are equal in size.

[0015] In some embodiments of the present invention, the second copper layer and the second welding layer have the same shape and are equal in size.

[0016] In some embodiments of the present invention, the cooling substrate is made of copper.

[0017] In some embodiments of the present invention, the packaging structure is silicone gel.

[0018] In some embodiments of the present invention, the IGBT power module further includes a shell, the shell covers one side of the cooling substrate, and the silicone gel is located inside the shell.

[0019] In some embodiments of the present invention, a gap is formed between the shell and the silicone gel.

[0020] In the solution of the utility model, the first welding layer and the second welding layer are respectively provided on both sides of the DBC ceramic sheet in the connection structure, the first welding layer is connected to the IGBT chip, the cooling substrate is connected to the second welding layer, and the packaging structure packages the IGBT chip and the DBC ceramic sheet in the cooling substrate. In this way, the structural connection strength between the DBC ceramic sheet and the IGBT chip and the cooling substrate located on both sides thereof is relatively high, ensuring the reliability and durability of the IGBT power module. On this basis, the IGBT chip can quickly conduct heat to the cooling substrate through the first welding layer, the DBC ceramic sheet and the second welding layer. Compared with the heat conduction solution using thermal grease, the heat dissipation efficiency and the maximum tolerable temperature of the IGBT power module in the utility model are higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained by the structures shown in these drawings without paying creative work.

[0022] Figure 1 This is a structural schematic diagram of an embodiment of an IGBT power module provided by the utility model.

[0023] Description of Figure Numbers:

[0024] 1. IGBT power module; 10. IGBT chip; 11. Metal bonding wire; 20. DBC ceramic sheet; 21. First copper layer; 211. Electrical connection part; 212. Welding part; 22. Second copper layer; 23. Ceramic layer; 30. Cooling substrate; 40. Packaging structure; 50. First welding layer; 60. Second welding layer; 70. Housing; 80. Gap.

[0025] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0028] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0029] The utility model proposes an IGBT power module 1, comprising an IGBT chip 10, a connection structure, a cooling substrate 30 and a packaging structure 40; wherein the connection structure comprises a first welding layer 50, a second welding layer 60 and a DBC ceramic sheet 20, the two sides of the DBC ceramic sheet 20 are respectively connected to the first welding layer 50 and the second welding layer 60, the first welding layer 50 is connected to the IGBT chip 10; the cooling substrate 30 is connected to the second welding layer 60; the packaging structure 40 encapsulates the IGBT chip 10 and the connection structure on the cooling substrate 30.

[0030] The IGBT chip 10 is used to connect with the motor to adjust the current of the motor, thereby controlling the speed and torque of the motor. The DBC ceramic sheet 20 has the functions of structural connection, heat conduction and insulation, and has excellent thermal conductivity and electrical insulation properties, and can meet the heat dissipation and insulation requirements of high-power electronic devices such as the IGBT chip 10.

[0031] The first welding layer 50 can connect the IGBT chip 10 and the DBC ceramic sheet 20 by gas welding, ultrasonic welding, laser welding, etc. Preferably, formic acid furnace welding is used. The formic acid furnace can provide a certain amount of hydrogen, so that during the welding process, hydrogen can react with oxygen to reduce the formation of oxides, thereby maintaining the purity of the weld and the molten pool, protecting the welding area from oxygen pollution, and improving the welding quality and efficiency. The welding method of the second welding layer 60 connecting the cooling substrate 30 and the DBC ceramic sheet 20 is similar to the welding method of the first welding layer 50, and formic acid furnace welding can also be used. The first welding layer 50 and the second welding layer 60 can be made of the same material or different materials, specifically tin sheet, silver-based solder or copper-based solder, which can be selected according to different substrates.

[0032] In the formic acid furnace welding method, different furnace temperatures are generally used to adapt to the first welding layer 50 and the second welding layer 60 of different materials and different melting points. For example, the first welding layer 50 is a lead-tin alloy tin sheet, and the formic acid furnace temperature is set at 240°C-245°C, specifically 240°C, 241°C, 242°C, 243°C, and 245°C; for another example, the second welding layer 60 is a copper-tin alloy tin sheet, and the formic acid furnace temperature is set at 270°C-280°C, specifically 270°C, 272°C, 275°C, 278°C, and 280°C.

[0033] The cooling substrate 30 is generally made of copper plate, which has good thermal conductivity, high strength, high temperature resistance and electromagnetic interference resistance. The cooling substrate 30 is generally water-cooled, which has high cooling efficiency. Of course, the cooling substrate 30 can also be made of other metal materials, and the cooling method can also be air-cooled. The packaging structure 40 can be silicone gel or epoxy resin, which is set according to the specific situation and is not limited here.

[0034] In the solution of the utility model, the first welding layer 50 and the second welding layer 60 are respectively provided on both sides of the DBC ceramic sheet 20 in the connection structure, the first welding layer 50 is connected to the IGBT chip 10, the cooling substrate 30 is connected to the second welding layer 60, and the packaging structure 40 packages the IGBT chip 10 and the DBC ceramic sheet 20 in the cooling substrate 30. In this way, the structural connection strength between the DBC ceramic sheet 20 and the IGBT chip 10 and the cooling substrate 30 located on both sides thereof is relatively high, ensuring the reliability and durability of the IGBT power module 1. On this basis, the IGBT chip 10 can quickly conduct heat to the cooling substrate 30 through the first welding layer 50, the DBC ceramic sheet 20 and the second welding layer 60, and the heat dissipation efficiency and the maximum tolerable temperature of the power module are relatively high.

[0035] In some embodiments of the utility model, the DBC ceramic sheet 20 has a ceramic layer 23 and a first copper layer 21 and a second copper layer 22 respectively connected to both sides of the ceramic layer 23, the first copper layer 21 is connected to the first welding layer 50, the second copper layer 22 is connected to the second welding layer 60, the second welding layer 60 is a copper-tin alloy tin sheet, and the material of the cooling substrate 30 is copper. In this way, the effect of welding the first copper layer 21 and the cooling substrate 30 using the copper-tin alloy tin sheet is good, and the structural strength is high.

[0036] In some embodiments of the present invention, the periphery of the ceramic layer 23 exceeds the first copper layer 21 and the second copper layer 22 to ensure the insulation effect.

[0037] In some embodiments of the present invention, the first copper layer 21 includes an electrical connection portion 211 and a welding portion 212, the IGBT chip 10 is connected to the electrical connection portion 211 via a metal bonding wire 11, the IGBT chip 10 is welded to the welding portion 212, the first copper layer 21 is connected to the first welding layer 50, and the first welding layer 50 is a lead-tin alloy tin sheet. The cost of welding the IGBT chip 10 to the welding portion 212 using a lead-tin alloy tin sheet is low, the welding process is stable, and the controllability is good.

[0038] Considering that when the shapes of the welding portion 212 and the first welding layer 50 do not match or are not equal in size, the two can only be connected through their own partial structures, and the heat conduction cross-sectional area is also small, and the heat dissipation is poor. Therefore, in some embodiments of the utility model, the welding portion 212 has the same shape and size as the first welding layer 50. Similarly, in other embodiments of the utility model, the second copper layer 22 has the same shape and size as the second welding layer 60. Thereby ensuring the connection strength and heat conduction effect.

[0039] In some embodiments of the present invention, the packaging structure 40 is made of silicone gel, so that the packaging structure 40 has good insulation performance and high temperature resistance. In some embodiments of the present invention, the cooling substrate 30 is a water-cooled plate.

[0040] Furthermore, in some embodiments of the present invention, the IGBT power module 1 further includes a housing 70 , the housing 70 covers one side of the cooling substrate 30 , and the silicone gel is located in the housing 70 , so as to improve the protection performance of the IGBT power module 1 .

[0041] In some embodiments of the present invention, a gap 80 is formed between the shell 70 and the silicone gel to prevent the silicone gel from overflowing from the shell 70 during packaging.

[0042] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An IGBT power module, characterized in that: include: IGBT chip; A connection structure, comprising a first welding layer, a second welding layer and a DBC ceramic sheet, wherein two sides of the DBC ceramic sheet are respectively connected to the first welding layer and the second welding layer, and the first welding layer is connected to the IGBT chip; a cooling substrate connected to the second welding layer; as well as Packaging structure; the packaging structure packages the IGBT chip and the connection structure on the cooling substrate.

2. The IGBT power module according to claim 1, characterized in that: The first soldering layer is tin sheet, silver-based solder or copper-based solder; and / or, The second soldering layer is tin sheet, silver-based solder or copper-based solder.

3. The IGBT power module according to claim 1, characterized in that: The DBC ceramic sheet comprises a ceramic layer and a first copper layer and a second copper layer respectively connected to both sides of the ceramic layer, the first copper layer is connected to the first welding layer, the second copper layer is connected to the second welding layer, the second welding layer is a copper-tin alloy sheet, and the cooling substrate is made of copper.

4. The IGBT power module according to claim 3, characterized in that: The first copper layer includes an electrical connection part and a welding part. The IGBT chip is connected to the electrical connection part via a metal bonding wire. The IGBT chip is welded to the welding part. The first copper layer is connected to the first welding layer. The first welding layer is a lead-tin alloy tin sheet.

5. The IGBT power module according to claim 4, characterized in that: The welding portion and the first welding layer have the same shape and are equal in size.

6. The IGBT power module according to claim 3, characterized in that: The second copper layer and the second welding layer have the same shape and are equal in size.

7. The IGBT power module according to claim 1, characterized in that: The cooling substrate is a water cooling plate.

8. The IGBT power module according to claim 1, characterized in that: The packaging structure is silicone gel.

9. The IGBT power module according to claim 8, characterized in that: The IGBT power module further includes a shell, which covers one side of the cooling substrate, and the silicone gel is located in the shell.

10. The IGBT power module according to claim 9, characterized in that: A gap is formed between the shell and the silicone gel.

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