Method for preparing composite sintered silver preformed sheet and method for packaging composite sintered silver preformed sheet

Abstract

The invention provides a method for preparing a composite sintered silver preformed sheet and a method for packaging a composite sintered silver preformed sheet. The preparing method comprises the steps of: mixing nanometer silver particles, micron silver particles, a sintering aid and an organic vehicle according to a certain ratio to obtain a composite silver paste, wherein the silver paste comprises the following components: in mass percentage, 5-20% of nanometer silver particles, 40-70% of mixed micron silver particles, 1-10% of sintering aid, 0.1-1% of leveling agent, 0.1-2% of de-foaming agent, 10-50% of mixed organic solvent, with the sum of the components being 100%. A film forming method uses spin coating, casting or screen printing followed by heating and drying. The packaging method comprises interconnecting a packaging structure by a hot press or dynamic embedded hot press sintering device. The composite sintered silver preformed sheet and the packaging scheme can be applied to a large-area power chip package, can solve the long process time and the narrow process window of a conventional unpressurized and pressurized sintering processes. The interconnected solder joints have high temperature resistance, cold and thermal shock resistance, and excellent service stability.

Description

technical field [0001] The invention relates to the field of electronic packaging, and more specifically, to a method for preparing and packaging a composite sintered silver preformed sheet. Background technique [0002] Low-temperature sintered silver technology is currently the most potential solution for power chip packaging. Sintered silver has excellent thermal and electrical conductivity, mechanical properties and service reliability. In addition, due to its small size effect, the material can realize solder joint interconnection at a lower temperature, and the silver structure after sintering has the same melting point (961°C) as bulk silver, which solves the problem of high-temperature solder brazing strips. Thermal mismatch, thermal device damage and other problems. [0003] The typical process of low-temperature sintering silver technology is to print silver paste on the substrate, mount it, and perform pressure-free or pressure-assisted sintering after a specific...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a composite sintered silver preform and packaging method, comprising, mixing nano-silver particles, micro-silver particles, sintering aids and organic carriers according to a certain ratio to obtain a composite silver paste, wherein the mixed silver paste The composition and mass percentage are: 5-20% of nano silver particles, 40-70% of mixed micron silver particles, 1-10% of sintering aid, 0.1-1% of leveling agent, 0.1-2% of defoamer, mixed organic solvent 10% to 50%, the sum of each component is 100%; the film forming method is spin coating, casting or screen printing and then heating and drying; the packaging method is using a hot press or dynamic embedded hot pressing sintering The equipment interconnects the packaging structure, aiming to solve the problems of the existing low-temperature sintering silver technology, such as complex process and time-consuming process