TW202215619A - Igbt module with heat-dissipation structure - Google Patents

Abstract

An IGBT module with a heat-dissipation structure includes a layer of IGBT chips, a bonding layer, a thick copper layer, a thermally-conductive and electrically-insulating layer, and a heat-dissipation layer. The thermally-conductive and electrically-insulating layer is disposed on the heat-dissipation layer. The thermally-conductive and electrically-insulating is partially composed of a polymer composite. The thermally-conductive and electrically-insulating is partially composed of a ceramic material. The thick copper layer is disposed on the thermally-conductive and electrically-insulating layer. The thick copper layer is formed with a rounded chamfer at the bottom. The bottom of the thick copper layer is embedded in the thermally-conductive and electrically-insulating layer. The bonding layer is disposed on the thick copper layer, and the layer of IGBT chips is disposed on the bonding layer for bonding to the thick copper layer.

Description

IGBT module heat dissipation structure

The present invention relates to an IGBT module, in particular to a heat dissipation structure of the IGBT module and a method for forming the same.

At present, the high-power inverters (Inverters) used in electric vehicles/hybrid electric vehicles mostly use IGBT (Insulated Gate Bipolar Transistor: Insulated Gate Bipolar Transistor) chips. Therefore, the heat generated when the high-power inverter works will cause the temperature of the IGBT chip to rise. Without proper heat dissipation measures, the temperature of the IGBT chip may exceed the allowable temperature, resulting in performance deterioration and damage. Therefore, IGBT heat dissipation technology has become a problem that relevant technicians are eager to solve.

At present, DBC (Direct Bonding Copper: ceramic-metal composite board structure) board has become the preferred material for the heat dissipation structure of IGBT modules. Please refer to FIG. 1 and FIG. 2 , which is a conventional IGBT module heat dissipation structure, which mainly includes an IGBT chip layer 11A, an upper solder layer 12A, a DBC board 13A, a lower solder layer 14A, and a heat dissipation layer 15A. The DBC board 13A includes an upper thin copper layer 131A, a ceramic layer 132A and a lower thin copper layer 133A in order from top to bottom. However, the DBC board 13A has a multi-layer structure and has limited thermal conductivity. When the IGBT chip 111A of the IGBT chip layer 11A generates heat, it cannot be transferred to the heat dissipation layer 15A through the DBC board 13A in time, and the DBC board 13A and the heat dissipation layer 15A must pass through Only the lower soldering layer 14A can form a connection, and a whole piece of the lower soldering layer 14A is prone to empty soldering phenomenon, which will increase the interface resistance, thereby affecting the thermal conductivity.

In view of this, the inventor of the present invention has been engaged in the development and design of related products for many years, and feels that the above deficiencies can be improved, so he has devoted himself to research and application of theories, and finally proposes a reasonable design and effectively improves the above deficiencies. The present invention.

The technical problem to be solved by the present invention is to provide an IGBT module heat dissipation structure and a method for forming the same in view of the deficiencies of the prior art.

In order to solve the above-mentioned technical problems, the present invention provides a heat dissipation structure of an IGBT module, which includes: an IGBT chip layer, a bonding layer, a thick copper layer, an insulating and heat-conducting layer, and a heat-dissipating layer; the insulating and heat-conducting layer is formed on the heat-dissipating layer. wherein, part of the insulating and heat-conducting layer is composed of polymer composite materials, and other parts of the insulating and heat-conducting layer are composed of ceramic materials; the thick copper layer is formed on the insulating and heat-conducting layer by hot pressing; wherein , the bottom of the thick copper layer is formed with a circular arc lead angle, and the bottom of the thick copper layer is embedded in the insulating and heat-conducting layer; the bonding layer is formed on the thick copper layer; the IGBT chip layer is formed over the bonding layer.

In a preferred embodiment, the ceramic material of the insulating and heat-conducting layer accounts for 50-95% of the weight of the insulating and heat-conducting layer.

In a preferred embodiment, the radius of the arc chamfer formed at the bottom of the thick copper layer is R0.3~R5mm.

In a preferred embodiment, the thickness of the thick copper layer is 1000-10000 μm.

In order to solve the above-mentioned technical problems, the present invention further provides a method for forming a heat dissipation structure of an IGBT module, comprising: (a) providing a pressing mold; (b) placing at least one thick copper plate into the pressing mold, and making the at least one thick copper plate flush with the pressing die, and forming a circular arc chamfer at the bottom of the at least one thick copper plate; (c) thermally pressing the pressing die together with the at least one thick copper plate To a heat dissipation layer formed with an insulating and thermally conductive layer, the bottom of the at least one thick copper plate is embedded in the insulating and thermally conductive layer, so that the at least one thick copper plate is formed as a thick copper layer formed on the insulating and thermally conductive layer. (d) removing the pressing mold; (e) forming a bonding layer on the thick copper layer; (f) forming an IGBT chip layer on the bonding layer.

In a preferred embodiment, the pressing mold is an anti-sticking pressing mold.

In a preferred embodiment, the pressing mold is formed with at least one hollow area for placing the at least one thick copper plate.

In a preferred embodiment, the area of the pressing mold is the same as the area of the heat dissipation layer.

The beneficial effect of the present invention is at least that, the insulating and heat-conducting layer of the present invention is partially composed of a polymer composite material, which can achieve the purpose of insulation and bonding. Furthermore, other parts of the insulating and heat-conducting layer of the present invention are made of ceramic materials, which can improve the heat-conducting effect. In addition, the bottom of the thick copper layer of the present invention is formed with an arc chamfer, so that when the bottom of the thick copper layer is embedded in the insulating and heat-conducting layer, the insulating and heat-conducting layer is not easily broken under pressure. In addition, the present invention transmits the heat generated by the IGBT chip to the heat dissipation fins of the entire heat dissipation layer quickly and uniformly through the thick copper layer and the insulating heat conduction layer. Compared with the DBC board with the existing IGBT module structure, the present invention can At the same time, it has the uniformity of heat dissipation of the thick copper layer and the insulation and thermal conductivity of the insulating and heat-conducting layer, and does not need to pass through the welding layer but directly forms an insulating and heat-conducting layer on the surface of the heat-dissipating layer, which will not cause empty welding problems and interfaces due to the welding layer. The impedance problem affects the thermal conductivity, and the multi-layer structure of the DBC board will not affect the thermal conductivity, so that the heat dissipation layer of the present invention can exert the maximum heat absorption and heat dissipation performance.

For a further understanding of the features and technical content of the present invention, please refer to the following detailed descriptions and drawings of the present invention. However, the drawings provided are only for reference and description, and are not intended to limit the present invention.

The following are specific specific examples to illustrate the embodiments disclosed in the present invention, and those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are merely schematic illustrations, and are not drawn according to the actual size, and are stated in advance. The following embodiments will further describe the related technical contents of the present invention in detail, but the disclosed contents are not intended to limit the protection scope of the present invention. In addition, the term "or", as used herein, should include any one or a combination of more of the associated listed items, as the case may be.

Please refer to FIG. 3 and FIG. 4 , an embodiment of the present invention provides a heat dissipation structure of an IGBT module. As shown in the figure, the heat dissipation structure of the IGBT module provided by the present invention includes the IGBT wafer layer 11 , the bonding layer 12 , the thick copper layer 13 , the insulating and thermally conductive layer 14 , and the heat dissipation layer 15 in order from top to bottom.

The insulating and thermally conductive layer 14 is formed on the heat dissipation layer 15 . The heat dissipation layer 15 may be an aluminum heat sink, a water cooling heat sink, or a metal plate with heat dissipation, but it is not limited thereto. In addition, the insulating and heat-conducting layer 14 is partially made of a polymer composite material, which can achieve the purpose of insulation and bonding. Furthermore, other parts of the thermally conductive insulating layer 14 are made of ceramic materials, so that the thermal conductivity can be improved.

Further, the polymer composite material contained in the insulating and heat-conducting layer 14 may be an epoxy resin composite material to form insulation. In addition, the ceramic material contained in the thermally conductive insulating layer 14 preferably accounts for 50-95% of the weight of the thermally conductive insulating layer 14 to achieve the best thermal conductivity effect.

In one embodiment, the insulating and heat-conducting layer 14 may be formed by mixing epoxy resin composite material and ceramic powder, but is not limited to this.

The thick copper layer 13 is formed on the insulating and heat-conducting layer 14, so that the thick copper layer 13 and the heat dissipation layer 15 can be insulated through the insulating and heat-conducting layer 14, and the thick copper layer 14 is formed. 13 can conduct heat to the heat dissipation layer 15 through the insulating and thermally conductive layer 14 .

Further, the thick copper layer 13 is bonded to the insulating and thermally conductive layer 14 containing ceramic material by thermocompression bonding, and the thick copper layer 13 may be formed of at least one thick copper plate 130 . In addition, in order to avoid that when the thick copper plate 130 is thermally bonded to the insulating and heat-conducting layer 14 to form the thick copper layer 13 , the insulating and heat-conducting layer 14 is easily broken by the pressure from the sharp corners of the thick copper plate 130 . Therefore, the thick copper plate 130 in this embodiment can also be said to be the thick copper layer 13 , and a circular arc chamfer 131 is formed at the bottom of the thick copper plate 130 , so that when the bottom of the thick copper layer 13 is embedded in the insulating and heat-conducting layer 14 , the insulating The thermally conductive layer 14 is not easily cracked under pressure.

Preferably, the radius of the arc chamfer 131 formed at the bottom of the thick copper layer 13 in this embodiment is R0.3˜R5 mm, so that when the bottom of the thick copper layer 13 is embedded in the insulating and thermally conductive layer 14, The insulating and heat-conducting layer 14 will not be broken under pressure.

In this embodiment, since the thick copper layer 13 is embedded in the insulating and heat-conducting layer 14 by thermocompression, the thickness of the thick copper layer 13 can be at least greater than 1000 μm, and can even reach 10000 μm. Therefore, compared with the thin copper layer of the DBC board of the existing IGBT module structure, which is about 300 μm, the IGBT module heat dissipation structure of the present invention can effectively increase the uniformity of heat dissipation through the thickness of the thick copper layer 13 of 1000-10000 μm. performance and overall heat transfer efficiency.

The bonding layer 12 is formed on the thick copper layer 13 , and the IGBT chip layer 11 is formed on the bonding layer 12 . The bonding layer 12 may be a tin bonding layer, but may also be a silver sintered layer. The IGBT chip layer 11 may be composed of at least one IGBT chip 111 . In addition, the IGBT chip layer 11 is connected to the thick copper layer 13 through the bonding layer 12 . When the IGBT chip 111 generates heat, the thick copper layer 13 and the insulating and heat-conducting layer 14 can conduct the heat to the heat dissipation layer 15 to dissipate heat to the outside.

Please refer to FIG. 5 to FIG. 9 , an embodiment of the present invention provides a method for forming a heat dissipation structure of an IGBT module, which mainly includes the following steps:

(a) A pressing mold 900 is provided. Wherein, the pressing mold 900 can be made of metal, rubber, or plastic, but in fact, various materials that can avoid sticking can be used, and are not limited to the above. That is to say, the pressing mold 900 of this embodiment may be an anti-sticking pressing mold.

(b) Put at least one thick copper plate 130 into the pressing mold 900 , and the at least one thick copper plate 130 can be flush with the pressing mold 900 to facilitate thermal pressing. Wherein, the pressing mold 900 is formed with at least one hollow area 901 where at least one thick copper plate 130 can be placed. The pressing mold 900 of this embodiment is formed with three hollow regions 901 for placing three thick copper plates 130 , and a circular arc chamfer 131 is formed at the bottom of the thick copper plates 130 . In addition, the area of the pressing mold 900 in this embodiment may be consistent with the area of the heat sink (ie, the heat dissipation layer 15 ), so as to facilitate positioning.

(c) thermally pressing the pressing die 900 together with the at least one thick copper plate 130 to a heat dissipation layer 15 formed with an insulating and thermally conductive layer 14, so that the bottom of the at least one thick copper plate 130 is embedded in the In the insulating and thermally conductive layer 14 , the at least one thick copper plate 130 is formed as a thick copper layer 13 and formed on the insulating and thermally conductive layer 14 . Since the bottom of the thick copper plate 130 in this embodiment is formed with an arc chamfer 131 , when the bottom of the thick copper plate 130 is embedded in the insulating and heat-conducting layer 14 , the insulating and heat-conducting layer 14 is not easily broken under pressure. In other embodiments, the plurality of thick copper plates 130 may be pre-formed with predetermined patterns, so that the required predetermined patterns are formed on the insulating and heat-conducting layer 14 by means of transfer printing.

(d) The pressing mold 900 is removed. Since the pressing mold 900 is an anti-sticking pressing mold, the pressing mold 900 can be easily removed after the thermal pressing is completed.

(e) forming a bonding layer 12 on the thick copper layer 13 .

(f) forming an IGBT chip layer 11 on the bonding layer 12 .

To sum up the above, the insulating and heat-conducting layer 14 of the present invention is partially composed of polymer composite materials, which can achieve the purpose of insulation and bonding. Furthermore, other parts of the insulating and heat-conducting layer 14 of the present invention are made of ceramic materials, which can improve the heat-conducting effect. In addition, the bottom of the thick copper layer 13 of the present invention is formed with an arc chamfer, so that when the bottom of the thick copper layer 13 is embedded in the insulating and heat-conducting layer 14, the insulating and heat-conducting layer 14 is not easily broken under pressure. In addition, the present invention uses the thick copper layer 13 and the insulating and thermally conductive layer 14 to quickly and uniformly conduct the heat generated by the IGBT chip to the heat dissipation fins of the entire heat dissipation layer 15. Compared with the existing IGBT mold The DBC board of the assembly structure, the present invention can simultaneously have the heat dissipation uniformity of the thick copper layer 13 and the insulation and thermal conductivity of the insulating and heat-conducting layer 14, and does not need to pass through the welding layer but directly forms the heat-dissipating layer on the surface of the heat-dissipating layer. The thermal conductivity will not be affected due to the void soldering problem and the interface impedance problem caused by the soldering layer, and the thermal conductivity will not be affected due to the multi-layer structure of the DBC board, so that the heat dissipation layer of the present invention can exert the maximum heat absorption and heat dissipation performance.

The contents disclosed above are only preferred feasible embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, any equivalent technical changes made by using the contents of the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

[current technology] 11A: IGBT chip layer 12A: Upper welding layer 13A: DBC board 131A: Upper thin copper layer 132A: Ceramic layer 133A: Lower thin copper layer 14A: Lower solder layer 15A: heat dissipation layer [this invention] 11: IGBT wafer layer 111: IGBT chip 12: Bonding layer 13: Thick copper layer 130: thick copper plate 131: Arc lead angle 14: Insulation and heat conduction layer 15: heat dissipation layer 900: Press mold 901: Hollow area

FIG. 1 is an exploded schematic side view of a heat dissipation structure of an IGBT module in the prior art.

FIG. 2 is a schematic side view of a heat dissipation structure of an IGBT module in the prior art.

FIG. 3 is a schematic exploded side view of the heat dissipation structure of the IGBT module of the present invention.

FIG. 4 is a schematic side view of the heat dissipation structure of the IGBT module of the present invention.

5 to 9 are schematic diagrams illustrating the formation process of the heat dissipation structure of the IGBT module of the present invention.

11: IGBT wafer layer

111: IGBT chip

12: Bonding layer

13: Thick copper layer

130: thick copper plate

131: Arc lead angle

14: Insulation and heat conduction layer

15: heat dissipation layer

Claims (7)

An IGBT module heat dissipation structure, comprising: an IGBT chip layer, a bonding layer, a thick copper layer, an insulating and heat-conducting layer, and a heat-dissipating layer; the insulating and heat-conducting layer is formed on the heat-dissipating layer; wherein, the insulating and heat-conducting layer is partially It is composed of polymer composite materials, and the other parts of the insulating and heat-conducting layer are composed of ceramic materials, so that the insulating and heat-conducting layer is an insulating and heat-conducting layer with a high content of ceramic materials; the thick copper layer is formed by hot pressing. above the insulating and heat-conducting layer; wherein, a circular arc chamfer is formed at the bottom of the thick copper layer, and the bottom of the thick copper layer is embedded in the insulating and heat-conducting layer; the bonding layer is formed between the thick copper layer on; the IGBT wafer layer is formed on the bonding layer. The heat dissipation structure of the IGBT module according to claim 1, wherein the ceramic material of the insulating and heat-conducting layer accounts for 50-95% of the weight of the insulating and heat-conducting layer. The heat dissipation structure of the IGBT module according to claim 2, wherein the radius of the arc lead angle formed at the bottom of the thick copper layer is R0.3~R5mm. The heat dissipation structure of the IGBT module according to claim 3, wherein the thickness of the thick copper layer is 1000-10000 μm. The heat dissipation structure of an IGBT module according to claim 1, wherein the thick copper layer is formed by pre-forming a plurality of thick copper plates with a predetermined pattern, so that the predetermined pattern is formed on the insulating and heat-conducting heat transfer method by transfer. above the layer. The heat dissipation structure of the IGBT module according to claim 1, wherein the insulating and heat-conducting layer is an insulating and heat-conducting layer formed by adding and mixing ceramic powder with epoxy resin composite material. The heat dissipation structure of the IGBT module according to claim 1, wherein the thick copper layer is thermally bonded to the insulating and heat-conducting layer by a pressing mold made of an anti-adhesion material together with a plurality of thick copper plates, so that the The thick copper layers are formed by embedding the bottoms of the plurality of thick copper plates in the insulating and heat-conducting layers.

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