TWM607186U - Heat dissipation structure of IGBT module - Google Patents

Abstract

An IGBT module heat dissipation structure includes: an IGBT wafer layer, a bonding layer, a thick copper layer, an insulating and heat conducting layer, and a heat dissipation layer. The insulating and thermally conductive layer is formed on the heat dissipation layer. The insulating and heat-conducting layer is partially made of polymer composite material, and the other parts of the insulating and heat-conducting layer are made of ceramic material. The thick copper layer is formed by hot pressing on the insulating and thermally conductive layer. A circular arc lead angle is formed at the bottom of the thick copper layer, and the bottom of the thick copper layer is embedded in the insulating and thermally conductive layer. The bonding layer is formed on the thick copper layer. The IGBT wafer layer is formed on the bonding layer.

Description

IGBT module heat dissipation structure

This creation relates to IGBT modules, specifically to the heat dissipation structure of IGBT modules and their forming methods.

At present, the high-power inverter (Inverter) used in electric vehicles/hybrid vehicles mostly uses IGBT (Insulated Gate Bipolar Transistor) chips. Therefore, the heat generated by the high-power inverter during operation 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, the IGBT heat dissipation technology has become a problem that related technicians are eager to solve.

At present, DBC (Direct Bonding Copper: ceramic-metal composite board structure) board has become the material of choice for the heat dissipation structure of IGBT modules. Please refer to FIG. 1 and FIG. 2, which is an existing IGBT module heat dissipation structure, which mainly includes an IGBT chip layer 11A, an upper welding layer 12A, a DBC board 13A, a lower welding layer 14A, and a heat dissipation layer 15A. Among them, the DBC board 13A includes an upper thin copper layer 131A, a ceramic layer 132A, and a lower thin copper layer 133A 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 solder layer 14A can form a connection, and a whole piece of the lower solder layer 14A is prone to empty soldering and increases the interface impedance, thereby affecting the thermal conductivity.

In view of this, the inventor of this creation has been engaged in the development and design of related products for many years, and feels that the above-mentioned shortcomings can be improved. He has devoted himself to research and cooperated with the use of academic principles, and finally proposed a rational design and effective improvement of the above-mentioned shortcomings. .

The technical problem to be solved by this creation is to provide an IGBT module heat dissipation structure and a method for forming the same for the shortcomings of the prior art.

In order to solve the above technical problems, this creation provides an IGBT module heat dissipation structure, including: an IGBT chip layer, a bonding layer, a thick copper layer, an insulating and thermally conductive layer, and a heat dissipation layer; the insulating and thermally conductive layer is formed between the heat dissipation layer On; wherein, the insulating and heat-conducting layer is partly composed of polymer composite materials, and the other parts of the insulating and heat-conducting layer are composed of ceramic materials; the thick copper layer is formed by hot pressing on the insulating and heat-conducting layer; 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 thermally conductive layer; the bonding layer is formed on the thick copper layer; the IGBT wafer layer is formed On the bonding layer.

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

In a preferred embodiment, the radius of the arc lead angle 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 technical problems, this creation provides another method for forming a heat dissipation structure of an IGBT module, which includes: (a) providing a pressing mold; (b) placing at least one thick copper plate into the pressing mold, and Make the at least one thick copper plate flush with the pressing mold, and the bottom of the at least one thick copper plate is formed with an arc lead angle; (c) hot pressing the pressing mold 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 and formed on the insulating layer On the thermal conductive layer; (d) removing the pressing mold; (e) forming a bonding layer on the thick copper layer; (f) forming an IGBT wafer 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 this creation is at least that the insulating and thermally conductive layer of this creation is partly composed of polymer composite materials, which can achieve the purpose of insulation and bonding. Furthermore, the other parts of the insulating and thermally conductive layer of this creation are made of ceramic materials, which can improve the thermal conductivity. In addition, the bottom of the thick copper layer of the present invention is formed with a circular arc lead angle, 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 easy to be cracked by pressure. Moreover, this creation can quickly and evenly conduct the heat generated by the IGBT chip to the heat dissipation fins of the entire heat dissipation layer through the thick copper layer and the insulating and thermal conductive layer. Compared with the existing DBC board of the IGBT module structure, this creation It can have both the uniformity of heat dissipation of the thick copper layer and the insulation and thermal conductivity of the insulating and thermally conductive layer, and the insulating and thermally conductive layer is directly formed on the surface of the heat dissipation layer without the soldering layer, which will not cause empty soldering problems due to the soldering layer. The interface impedance problem affects the thermal conductivity, and will not affect the thermal conductivity due to the multi-layer structure of the DBC board, so that the heat dissipation layer of the invention can maximize the heat absorption and heat dissipation performance.

In order to have a better understanding of the features and technical content of this creation, please refer to the following detailed descriptions and drawings about this creation. However, the provided drawings are only for reference and explanation, not to limit this creation.

The following are specific specific examples to illustrate the related implementations disclosed in this creation, and those skilled in the art can understand the advantages and effects of this creation from the content disclosed in this specification. This creation 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 this creation. In addition, the drawings in this creation are merely schematic illustrations, and are not depicted in actual size, and are stated in advance. The following embodiments will further describe the related technical content of this creation in detail, but the disclosed content is not intended to limit the protection scope of this creation. In addition, the term "or" used in this document may include any one or a combination of more of the associated listed items depending on the actual situation.

Please refer to FIG. 3 and FIG. 4, this creative embodiment provides an IGBT module heat dissipation structure. As shown in the figure, according to the heat dissipation structure of the IGBT module provided by this creation, from top to bottom, there are an IGBT chip layer 11, a bonding layer 12, a thick copper layer 13, an insulating and thermal conductive layer 14, and a heat dissipation layer 15.

The insulating and thermally conductive layer 14 is formed on the heat dissipation layer 15. Wherein, the heat dissipation layer 15 may be an aluminum heat sink, a water-cooled heat sink, or a metal plate with heat dissipation function, but it is not limited to this. In addition, the insulating and thermally conductive layer 14 is partly composed of a polymer composite, which can achieve the purpose of insulation and bonding. Furthermore, the other parts of the insulating and heat-conducting layer 14 are made of ceramic materials, so that the heat-conducting effect can be improved.

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

In an embodiment, the insulating and thermally conductive layer 14 may be formed by mixing epoxy resin composite material with ceramic powder, but it is not limited thereto.

The thick copper layer 13 is formed on the insulating and thermally conductive layer 14, so that the thick copper layer 13 and the heat dissipation layer 15 can pass through the insulating and thermally conductive layer 14 to form insulation, and make the thick copper layer 13 can conduct heat to the heat dissipation layer 15 through the insulating and thermally conductive layer 14.

Furthermore, the thick copper layer 13 is joined to the insulating and thermally conductive layer 14 including ceramic material by thermocompression bonding, and the thick copper layer 13 may be formed by at least one thick copper plate 130. In addition, in order to prevent the thick copper plate 130 from being thermally press-bonded to the insulating and thermally conductive layer 14 to form the thick copper layer 13, the insulating and thermally conductive layer 14 is easily broken by the sharp corner pressure of the thick copper plate 130. Therefore, the thick copper plate 130 of this embodiment can also be said to be the thick copper layer 13, with a circular arc corner 131 formed at the bottom, so that when the bottom of the thick copper layer 13 is embedded in the insulating and thermally conductive layer 14, the insulating The thermally conductive layer 14 is not easily broken by being pressed.

Preferably, the radius of the arc angle 131 formed at the bottom of the thick copper layer 13 in this embodiment is R0.3~R5mm, so that when the bottom of the thick copper layer 13 is embedded in the insulating and thermally conductive layer 14, The insulating and thermally conductive layer 14 will not break under pressure.

In this embodiment, since the thick copper layer 13 is embedded in the insulating and thermally conductive layer 14 by thermocompression bonding, 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 300μm, the heat dissipation structure of the IGBT module of the invention can effectively increase the uniformity of heat dissipation through the thickness of the thick copper layer 13 being 1000~10000μm. Performance and overall heat transfer efficiency.

The bonding layer 12 is formed on the thick copper layer 13, and the IGBT wafer 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 wafer 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 thermally conductive layer 14 can conduct heat to the heat dissipation layer 15 to dissipate heat outward.

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

(a) Provide a pressing mold 900. 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. In other words, 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. The at least one thick copper plate 130 may 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 for placing at least one thick copper plate 130. The pressing mold 900 of this embodiment is formed with three hollow areas 901 for placing three thick copper plates 130, and the bottom of the thick copper plate 130 is formed with an arc corner 131. In addition, the area of the pressing mold 900 of this embodiment can be the same as the area of the heat sink (that is, the heat dissipation layer 15) to facilitate positioning.

(c) The pressing mold 900 together with the at least one thick copper plate 130 is thermally pressed onto 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 on the insulating and thermally conductive layer 14. Since the bottom of the thick copper plate 130 of this embodiment is formed with a circular arc lead angle 131, when the bottom of the thick copper plate 130 is embedded in the insulating and thermally conductive layer 14, the insulating and thermally conductive layer 14 is not easy to be cracked under pressure. In other embodiments, a plurality of thick copper plates 130 may be pre-formed with a predetermined pattern, so that the required predetermined pattern is formed on the insulating and thermally conductive layer 14 by means of transfer.

(d) Remove the pressing mold 900. 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) A bonding layer 12 is formed on the thick copper layer 13.

(f) An IGBT wafer layer 11 is formed on the bonding layer 12.

In summary, the insulating and thermally conductive layer 14 of the present creation is partially composed of polymer composite materials, which can achieve the purpose of insulation and bonding. Furthermore, the other parts of the insulating and heat-conducting layer 14 of this creation 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 a circular arc lead angle, so that when the bottom of the thick copper layer 13 is embedded in the insulating and thermally conductive layer 14, the insulating and thermally conductive layer 14 is not easy to be cracked under pressure. In addition, this creation uses the thick copper layer 13 and the insulating and thermally conductive layer 14 to quickly and evenly conduct the heat generated by the IGBT chip to the heat dissipation fins of the heat dissipation layer 15, which is compared with the existing IGBT mold. The DBC board of the group structure can simultaneously have the heat dissipation uniformity of the thick copper layer 13 and the insulation and thermal conductivity of the insulating and thermally conductive layer 14, and the insulating and thermally conductive layer is directly formed on the surface of the heat dissipation layer without the need for soldering. The thermal conductivity will be affected due to the soldering layer's void soldering problems and interface impedance problems, and the multi-layer structure of the DBC board will not affect the thermal conductivity, so that the creative heat dissipation layer can exert the maximum heat absorption and heat dissipation performance.

The content disclosed above is only a preferred and feasible embodiment of the creation, and does not limit the scope of the patent application for this creation. Therefore, all equivalent technical changes made using the creation specification and schematic content are included in the application for this creation. Within the scope of the patent.

[current technology] 11A: IGBT wafer layer 12A: Upper welding layer 13A: DBC board 131A: Upper thin copper layer 132A: Ceramic layer 133A: Lower thin copper layer 14A: Lower welding layer 15A: Heat dissipation layer [This Creation] 11: IGBT wafer layer 111: IGBT chip 12: Bonding layer 13: Thick copper layer 130: thick copper plate 131: arc lead angle 14: Insulating and thermal conductive layer 15: heat dissipation layer 900: pressing mold 901: hollow area

FIG. 1 is an exploded schematic diagram of a 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.

Figure 3 is an exploded side view schematic diagram of the IGBT module heat dissipation structure created.

Figure 4 is a schematic side view of the heat dissipation structure of the IGBT module created.

Figures 5 to 9 are schematic diagrams of the formation process of the IGBT module heat dissipation structure created.

11: IGBT wafer layer

111: IGBT chip

12: Bonding layer

13: Thick copper layer

130: thick copper plate

131: arc lead angle

14: Insulating and thermal conductive layer

15: heat dissipation layer

Claims (4)

An IGBT module heat dissipation structure, comprising: an IGBT wafer layer, a bonding layer, a thick copper layer, an insulating and heat-conducting layer, and a heat dissipation layer; the insulating and heat-conducting layer is formed on the heat dissipation layer; wherein the insulating and heat-conducting layer part It is composed of a polymer composite material, and the other parts of the insulating and heat-conducting layer are made of ceramic materials; the thick copper layer is formed by hot pressing on the insulating and heat-conducting layer; wherein a circle is formed at the bottom of the thick copper layer Arc lead angle, and the bottom of the thick copper layer is embedded in the insulating and thermally conductive layer; the bonding layer is formed on the thick copper layer; and the IGBT wafer layer is formed on the bonding layer. The IGBT module heat dissipation structure according to claim 1, wherein the ceramic material of the insulating and thermally conductive layer accounts for 50-95% of the weight of the insulating and thermally conductive layer. The IGBT module heat dissipation structure according to claim 2, wherein the radius of the arc corner formed at the bottom of the thick copper layer is R0.3~R5mm. The IGBT module heat dissipation structure according to claim 3, wherein the thickness of the thick copper layer is 1000-10000 μm.

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