An igbt module package welding structure

Abstract

The invention discloses an IGBT (insulated gate bipolar transistor) module encapsulating and welding structure which comprises a substrate, a lining plate, a chip and a busbar, wherein the upper surfaces of the substrate and the lining plate are coated with welding fluxes or provided with welding lugs; the substrate and the lining plate, the lining plate and the chip and the busbar and the lining plate are respectively connected through multiple metal supporting columns. The metal supporting columns which are 0-5mm thick are manufactured on a metal layer on the front surface of the lining plate and a welding region on the front surface of the substrate and are used for supporting the chip and the lining plate, so that the welding fluxes can uniformly flow after being melted to fill clearances, and the thickness and the uniformity of a welding layer are controlled; the metal supporting columns can be used for fixing the welding lugs with through holes, and sliding and drifting of the welding lugs in a welding process are avoided.

Description

technical field [0001] The invention relates to an IGBT module packaging and welding structure. Background technique [0002] At present, the packaging design structure and process of power IGBT modules are mainly based on welding methods. In this structure, the chip is connected to the liner by welding, and the liner after welding the chip is welded with the substrate, and at the same time, the busbar is also welded to the liner synchronously, such as figure 1 shown. [0003] In the current IGBT module process, there are two main technical routes for welding: [0004] (1) Solder paste process: Print the solder paste on the surface of the liner and the substrate by screen printing, use the viscosity of the solder paste to fix the chip on the surface of the liner, and then fix the liner with the chip soldered on the substrate, at the same time Use the clamp to fix the busbar on the liner, and then carry out vacuum welding. [0005] (2) Soldering sheet process: Fix the lin...

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Problems solved by technology

[0007] (1) After the solder is melted, the fluidity on the surface of the liner and the substrate is different, resulting in inconsistent thickness of the solder layer after cooling. Under the same chip or liner, the solder in some areas is thicker, while the solder in other areas is thinner. like figure 2 As shown, it will not only affect the heat dissipation performance of the module, but also easily generate cracks in the thinner solder layer area during the periodic temperature change process, which will affect the long-term reliability of the module;

[0008] (2) Due to the certain deformation of the liner and the substrate itself, the uneven distribution of the thickness of the solder layer will be aggravated;

[0009] (3) When welding the busbar terminal to the liner, it is necessary to wrap the soldering piece on the busbar pin, or use tooling to fix the soldering piece and the busbar, and the assembly efficiency is low

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