IGBT module packaging welding method and packaging welding structure

Abstract

The invention provides an IGBT module packaging welding method and an IGBT module packaging welding structure. The IGBT module packaging welding method comprises the following steps: 1) a welding area and a non welding area on the surface of a heat radiator are isolated; 2) a uniform welding flux layer is arranged in the welding area; and 3) an insulated linear is welded and fixed with the heat radiator through the welding flux layer. the IGBT module packaging welding structure comprises the insulated linear and the heat radiator for cooling the insulated linear, wherein the surface of the heat radiator is provided with the welding area for welding the insulated linear; the welding flux layer is arranged in the welding area; and the insulated linear is welded in the welding area through the welding flux layer. The method and the structure of the invention have the advantages that the heat radiation efficiency is high; the packaging difficulty is low; and the use performance of the IGBT element and the operation reliability can be ensured.

Description

technical field [0001] The invention relates to the packaging design field of power modules, in particular to an IGBT module packaging and welding method and a packaging and welding structure. Background technique [0002] At present, IGBT (Insulated Gate Bipolar Transistor, full name "Insulated Gate Bipolar Transistor") chip is usually provided with circuit structure, electrical insulation and mechanical support by insulating liner, while the heat dissipation efficiency, performance and operation reliability of insulating liner depend on Packaging technology for insulating substrates. The existing IGBT module packaging and welding structure mainly adopts two methods: one is to weld the insulating liner on the substrate to package the IGBT module, and then install it with the silicon grease and the radiator. It uses the IGBT module as a unit to carry out power The selection of grades has the characteristics of strong versatility, detachable and interchangeable, and simple d...

AI Technical Summary

Problems solved by technology

The existing IGBT module packaging and welding structure mainly adopts two methods: one is to weld the insulating liner on the substrate to package the IGBT module, and then install it with the silicon grease and the radiator. It uses the IGBT module as a unit to carry out power The selection of grades has the characteristics of strong versatility, detachable and interchangeable, and simple drive design, which reduces the requirements for application development level, but there are the following problems: 1. The insulating liner is installed on the radiator through the base plate. This results in an extra portion of thermal resistance links in the heat exchange path between the insulating liner and the radiator, which results in a large thermal resistance from the insulating liner to the radiator, restricting the heat dissipation efficiency of the insulating liner, and making it difficult to increase the IGBT power level; 2. To ensure The large substrate is in good contact with the surface of the heat sink, and the plane of the large substrate needs to be crowned. The substrate manufacturing is complicated and the cost is high; 3. When the substrate is in poor contact due to thermal expansion, the performance of the IGBT and the reliability of the IGBT module are reduced, which increases the system operation. 4. The insulating lining board needs to use specific tooling to ensure the welding effect, and the welding process of the insulating lining board is complicated; 5. The welding uniformity, large substrate plane camber, and parallel insulating lining boards Due to the influence of current uniformity, there are problems such as complicated welding process of insulating liner, difficult packaging, and inability to guarantee IGBT performance and long-term operation reliability.

The contact thermal resistance between the silicone grease and the two contact surfaces is caused by physical contact. The contact thermal resistance of the two layers is larger than the thermal resistance of the silicone grease itself, and occupies a large amount of heat in the entire heat transfer path from the insulating liner to the radiator. The resistance ratio restricts the heat dissipation efficiency of the insulating liner; in addition, as the temperature rises, the fluidity of the silicone grease increases, and the overflow and diffusion of the silicone grease will lead to a sharp increase in the contact thermal resistance, which induces system risks. At the same time, the fluidity of the silicone grease There is also no guarantee of seamless filling

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