Vacuum welding method for thick film substrate and power shell

Abstract

The invention belongs to the technical field of electronic installation and relates to a vacuum welding method for a thick film substrate and a power shell. Tin coating is conducted on the surface of a raw material according to the ratio of 1:1, and a high brazing rate with the voidage smaller than 5% is achieved. An SiC-Al composite material power shell is adopted to replace a 10# steel shell, and the product weight is reduced. Vacuum welding is adopted to replace reflow soldering, soldering lug Tin coating is adopted to replace soldering paste, it is favorable for removing residual bubbles caused by the fact that soldering flux is not discharged in time, the interface voidage is reduced, and the soldering flux does not need to be cleaned any more after vacuum welding. During vacuum welding, a soldering lug does not need to be added between the thick film substrate and the power shell, empty welding holes caused by surface oxidation of the soldering lug can be effectively removed, oxidation films on the surfaces of the thick film substrate and the power shell are removed by conducting Tin coating on the thick film substrate and the power shell, the clean welded surfaces are obtained, the wettability is improved, and an exhausting channel is smoother in the welding process.

Description

technical field [0001] The invention relates to a vacuum welding method for a thick-film substrate and a power casing, which uses 1:1 tinning on the surface of raw materials to achieve a high brazing rate with a void rate of less than 5%, and belongs to the technical field of electronic assembly. Background technique [0002] As aerospace power electronic products continue to be miniaturized and lightweight, traditional high-power module power supplies are transforming into thick-film modules. Thick film module is to replace the power components (such as power MOS tube) in the traditional high-power module power supply with the bare chip, so as to achieve the purpose of reducing the volume and weight, but the bare chip has high requirements for heat dissipation, so it needs Mount it on a thick film ceramic substrate and power case to form a good heat dissipation channel. [0003] High-power power supply products have high power density and large transmission current. It is ...

AI Technical Summary

Problems solved by technology

The void rate of the welding interface between the thick film substrate and the power casing has always been the focus of people's attention. If the void rate is too high, it will increase the thermal resistance and reduce the bearing area of ​​the joint, thereby reducing the thermal conductivity and joint strength.

[0004] With the lightweight requirements of aerospace products, traditional 10# steel power casings often cannot meet the requirements in terms of weight, and the use of new lightweight power casings has become the development direction

At the same time, the traditional welding of 10# steel and power casing is carried out by reflow welding process, and the interface void rate is relatively large

This poses new challenges to the welding process of thick film substrates and lightweight power enclosures

Images