A copper paste that can be sintered at low temperature and high density

Abstract

The invention relates to the field of metal composite materials, in particular to a copper paste which can be used for low-temperature sintering and can obtain low porosity. The copper paste includes: spherical copper particles, flaky copper particles, flaky indium particles and high-linkage resin; the two kinds of copper particles account for more than 80%, indium particles account for 10‑20%, and high-linkage resin accounts for more than 80%. Between 0‑10%. Under the condition of no pressure, the sintering temperature of the copper paste can be as low as 180-250° C., and the density after sintering can reach more than 95%.

Description

technical field [0001] The present application relates to the field of metal composite materials, in particular to the preparation of a copper paste that can be used for low-temperature and low-pressure sintering. Background technique [0002] A new generation of power modules for electric vehicles, aviation, and other industries requires high power and high service temperature. It has been demonstrated in the past 10 years that wide bandgap semiconductors can withstand high operating temperatures above 300°C. However, traditional packaging materials, such as tin-based solders and conductive adhesives, are limited to operation below 200°C. Researchers have been looking for ways to achieve high reliability at high temperature and high power. In past explorations, the sintering of highly conductive and conductive silver or copper among metals has been found to be a promising approach. For cost considerations, copper sintering is a technology that has been tried in recent ye...

AI Technical Summary

Problems solved by technology

At present, many nano-copper particles are mostly spherical, and some of them are difficult to achieve mutual fusion and sintering even below 30 nanometers. The main problem is that the oxidation problem of copper surface has always existed. As the surface energy increases, the chance of interdiffusion of metal atoms increases, but the oxidation tendency is also more intensified. Therefore, it is a great challenge to reduce the temperature of copper sintering

At the same time, sinter porosity is also a problem to be considered, because the porosity will reduce the thermal conductivity and the reliability of the sintering point

[0003] The document "Development of Die Attachment Technology for Power IC Module yIntroducing Indium into Sintered Nano-Silver Joint", 2017 IEEE 67th Electronic Component and Technology Conference records that adding indium foil to silver sintered materials will reduce the oxidation of copper matrix during use and service , and the reliability of the device has also been greatly improved, probably because of the barrier of the Cu-In intermetallic compound

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