A method of soldering power semiconductor module terminals to a substrate

Abstract

Disclosed is a method for welding a power semiconductor module terminal to a substrate. According to the method, the terminal and the substrate are made of the same material or materials with similar coefficients of thermal expansion, wherein the substrate is arranged on a radiating substrate in a reflow soldering mode, and the terminal is fixed above the welding position of the substrate; the welding surface of the terminal is made in smooth contact with the upper surface of the substrate; the radiating substrate is fixed; the welding surface of an ultrasonic welding head is made in horizontal alignment with the upper welding surface of the terminal; pressure is applied to the ultrasonic welding head in the vertical direction of the plane of the substrate to enable the working surface of the ultrasonic welding head to be in smooth contact with the upper welding surface of the terminal; the ultrasonic welding head applies ultrasonic energy to the terminal and the substrate sufficient enough to enable the terminal to be welded to the substrate. According to the method, the temperature shock resistance of the junction surface between the power semiconductor module terminal and the substrate is improved, and the service life of a power semiconductor module is prolonged.

Description

technical field [0001] The invention relates to a method for welding power semiconductor module terminals to a substrate, and belongs to the technical field of semiconductor packaging and power semiconductor module preparation. Background technique [0002] Currently, in the packaging process of power semiconductor modules, power terminals or signal terminals are welded to the module by soldering technology. During the use of the power semiconductor module, its temperature will frequently fluctuate between high temperature (100-150°C) and room temperature, because the metal material used for the terminal, the surface material of the terminal to be welded to the substrate, and the thermal expansion coefficient of the solder are different and different Larger, under this temperature fluctuation, the solder on the soldering surface will generate stress on the terminal surface and the surface of the substrate in contact with it. When the stress reaches a certain value, cracks a...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the deficiencies in the prior art above, the present invention provides a method for welding the terminals of the power semiconductor module to the substrate, which can effectively solve the problem of terminal drop due to different thermal expansion coefficients of different materials during the use of the power semiconductor module. problem, but also can reduce the module production cycle time and improve production efficiency

Images