TWI792059B - Method of manufacturing 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

Method for forming heat dissipation structure of IGBT module

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

At present, the high-power inverter (Inverter) used in electric vehicles/hybrid vehicles mostly uses IGBT (Insulated Gate Bipolar Transistor: Insulated Gate Bipolar Transistor) chips. Therefore, the heat generated during the operation of the high-power inverter will cause the temperature of the IGBT chip to rise. If there is no proper heat dissipation measure, the temperature of the IGBT chip may exceed the allowable temperature, resulting in performance deterioration and even damage. Therefore, the IGBT heat dissipation technology has become a problem that relevant technicians are eager to solve.

At present, the DBC (Direct Bonding Copper: ceramic-metal composite board structure) board has become the material of choice for the heat dissipation structure of the IGBT module. 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 solder layer 12A, a DBC board 13A, a lower solder layer 14A, and a heat dissipation layer 15A. Wherein, 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 there must be an air gap between the DBC board 13A and the heat dissipation layer 15A. 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, and will increase the interface resistance, thereby affecting the thermal conductivity.

In view of this, the inventor has been engaged in the development and design of related products for many years, and felt that the above-mentioned defects can be improved, so he devoted himself to research and combined with the application of theories, and finally proposed an invention with a reasonable design and effective improvement of the above-mentioned defects.

The technical problem to be solved by the present invention is to provide an IGBT module heat dissipation structure and a forming method thereof 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, comprising: an IGBT chip layer, a bonding layer, a thick copper layer, an insulating heat conducting layer, and a heat dissipation layer; the insulating heat conducting layer is formed on the heat dissipation layer above; wherein, the insulating and heat-conducting layer part is made of polymer composite material, and the other part of the insulating and heat-conducting layer is made of ceramic material; the thick copper layer is hot-pressed and formed on the insulating and heat-conducting layer; wherein , the bottom of the thick copper layer is formed with an arc chamfer, 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 thick copper layer has a thickness of 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) putting 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 chamfer; (c) hot pressing the pressing mold together with the at least one thick copper plate On a heat dissipation layer formed with an insulating and heat-conducting layer, the bottom of the at least one thick copper plate is embedded in the insulating and heat-conducting layer, so that the at least one thick copper plate is formed as a thick copper layer (d) remove the pressing mold; (e) form a bonding layer on the thick copper layer; (f) form an IGBT chip layer on the bonding layer above.

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 consistent with the area of the heat dissipation layer.

The beneficial effects of the present invention at least lie in that the insulation and heat conduction layer of the present invention is partly made of polymer composite materials, so that the purpose of insulation and bonding can be achieved. Furthermore, the other parts of the insulation and heat conduction layer of the present invention are made of ceramic materials, which can improve the heat conduction effect. Moreover, the bottom of the thick copper layer of the present invention is formed with a circular arc leading 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 easily broken due to pressure. Moreover, the present invention uses the thick copper layer and the insulating and heat-conducting layer to quickly and evenly guide the heat generated by the IGBT chip to the heat dissipation fins of the entire heat dissipation layer. Compared with the DBC board of the existing IGBT module structure, the present invention can At the same time, it has the heat dissipation uniformity 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 solder layer but directly forms the insulating and heat-conducting layer on the surface of the heat-dissipating layer, which will not cause the problem of empty soldering and interface due to the soldering layer The thermal conductivity is affected by the impedance problem, and the thermal conductivity will not be affected by 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.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the provided drawings are only for reference and description, and are not intended to limit the present invention.

[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 soldering layer

15A: heat dissipation layer

[this invention]

11: IGBT chip 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: 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 the heat dissipation structure of the 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 of the forming process of the heat dissipation structure of the IGBT module of the present invention.

The following are specific examples to illustrate the implementation methods disclosed in the present invention. 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 modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple illustration, and are not drawn according to the actual size, which is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention. In addition, the term "or" used herein 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 , an embodiment of the present invention provides a heat dissipation structure for an IGBT module. As shown in the figure, the heat dissipation structure of the IGBT module provided by the present invention includes the IGBT chip layer 11 , bonding layer 12 , thick copper layer 13 , insulating and heat conducting layer 14 , and heat dissipation layer 15 in sequence from top to bottom.

The insulation and heat conduction 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, but it is not limited thereto. In addition, the insulating and heat-conducting layer 14 is partly made of polymer composite, so as to achieve the purpose of insulation and bonding. Furthermore, other parts of the insulating and heat-conducting layer 14 are made of ceramic materials, so as to improve the heat-conducting effect.

Further, the polymer composite material contained in the insulating and heat-conducting layer 14 can be It is an epoxy resin composite material used to form insulation. In addition, the ceramic material included in the insulating and heat-conducting layer 14 preferably accounts for 50-95% of the weight of the insulating and heat-conducting layer 14, so as to achieve the best heat-conducting effect.

In one embodiment, the insulating and heat-conducting 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 heat-conducting layer 14, so that the insulation between the thick copper layer 13 and the heat-dissipating layer 15 can be formed through the insulating and heat-conducting layer 14, and the thick copper layer 13 can conduct heat to the heat dissipation layer 15 through the insulating and heat conducting layer 14 .

Further, the thick copper layer 13 is bonded to the insulating and heat-conducting layer 14 including ceramic material by thermocompression, and the thick copper layer 13 may be composed 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 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, and its bottom is formed with a rounded corner 131, so that when the bottom of the thick copper layer 13 is embedded in the insulating and heat-conducting layer 14, the insulating The heat conducting layer 14 is not easy to be 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~R5mm, 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 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 has a thickness of 1000-10000 μm through the thick copper layer 13, which can effectively increase the uniformity of heat dissipation. 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 can be a tin bonding layer, but also a silver sintering layer. The IGBT chip layer 11 may be composed of at least one IGBT chip 111 . Moreover, the IGBT chip layer 11 is connected to the thick copper layer 13 through the bonding layer 12 . When the IGBT chip 111 heats up, the heat can be conducted to the heat dissipation layer 15 through the thick copper layer 13 and the insulating heat conduction layer 14 to dissipate heat outward.

Please refer to FIG. 5 to FIG. 9. The 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, 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 , 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 plates 130 is formed with a rounded corner 131 . Moreover, the area of the pressing mold 900 in this embodiment may be consistent with the area of the heat sink (that is, the heat dissipation layer 15 ), so as to facilitate positioning.

(c) Thermally press-bond the pressing mold 900 together with the at least one thick copper plate 130 onto a heat dissipation layer 15 formed with an insulating and heat-conducting layer 14, so that the bottom of the at least one thick copper plate 130 is embedded in the In the insulating and heat-conducting layer 14 , the at least one thick copper plate 130 is formed as a thick copper layer 13 and formed on the insulating and heat-conducting layer 14 . Since the bottom of the thick copper plate 130 in this embodiment is formed with a circular 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 due to pressure. In other embodiments, a plurality of thick copper plates 130 can be pre-formed with predetermined patterns, so that the required predetermined patterns can be formed on the insulating surface by transfer printing. on the thermal conduction layer 14.

(d) removing 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 heat pressing is finished.

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

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

Based on the above, the insulating and heat-conducting layer 14 of the present invention is partially made of polymer composite materials, so as to 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. Moreover, the bottom of the thick copper layer 13 of the present invention is formed with a rounded 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 due to pressure. Moreover, the present invention uses the thick copper layer 13 and the insulating and heat-conducting layer 14 to quickly and uniformly guide the heat generated by the IGBT chip to the heat dissipation fins of the entire heat dissipation layer 15. Compared with the existing IGBT die The DBC board with a group 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 directly form the insulating and heat-conducting layer on the surface of the heat-dissipating layer without passing through the solder layer, without The heat conduction performance will be affected by the problem of empty soldering and interface impedance caused by the welding layer, and the heat conduction performance will not be affected by 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 content disclosed above is only a preferred feasible embodiment of the present invention, and does not therefore limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. within the scope of the patent.

11: IGBT chip 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 (8)

A method for forming a heat dissipation structure of an IGBT module, comprising: (a) providing a pressing mold; (b) putting at least one thick copper plate into the pressing mold, and a circular arc is formed at the bottom of the at least one thick copper plate chamfer; (c) thermally pressing the pressing mold together with the at least one thick copper plate onto a heat dissipation layer formed with an insulating and heat-conducting layer, so that the bottom of the at least one thick copper plate is embedded in the insulating and heat-conducting layer , so that the at least one thick copper plate is formed as a thick copper layer formed on the insulating and heat-conducting layer; (d) removing the pressing mold; (e) forming a bonding layer on the thick on the copper layer; (f) forming an IGBT chip layer on the bonding layer. The method for forming a heat dissipation structure of an IGBT module according to claim 1, wherein the pressing mold is an anti-sticking pressing mold. The method for forming a heat dissipation structure of an IGBT module according to claim 1, wherein the pressing mold is formed with at least one hollow area for placing the at least one thick copper plate. The method for forming a heat dissipation structure of an IGBT module according to claim 1, wherein the area of the pressing mold is consistent with the area of the heat dissipation layer. The method for forming a heat dissipation structure of an IGBT module according to claim 1, wherein the insulating and heat-conducting layer part is made of a polymer composite material, and the other part of the insulating and heat-conducting layer is made of a ceramic material. The method for forming a heat dissipation structure of an IGBT module according to claim 5, 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 method for forming the heat dissipation structure of the IGBT module according to claim 6, wherein the radius of the arc chamfer formed at the bottom of the thick copper plate is R0.3~R5mm. The method for forming a heat dissipation structure of an IGBT module according to claim 7, wherein the thick copper layer has a thickness of 1000-10000 μm.

Images