Multi-size mixed nano-particle paste and preparation method thereof

Abstract

The invention provides multi-size mixed nano-particle paste and a preparation method thereof, and the method comprises the steps: preparing large-size nano-copper paste through a chemical method, endowing small-size nano-metal particles with kinetic energy through a physical impact method, putting the small-size nano-metal particles into the large-size nano-copper paste, and preparing the large-size and small-size mixed nano-metal composite paste. When the paste is used in a sintering process, the small-size nano metal particles can be filled in gaps of the large-size nano metal particles, sothat nano copper connection can be realized under the condition of no pressure assistance, and the compactness of a sintered metal layer is improved. Meanwhile, the content of the small-size nano metal particles inputted by the physical method is controllable, the operation is easy and convenient, and the method is suitable for mass production.

Description

technical field [0001] The invention relates to the field of chip packaging, in particular to the preparation technology of metal paste. Background technique [0002] In the field of power semiconductor packaging, it is an urgent problem to seek low-temperature technology, high-temperature service, matching thermal expansion coefficient, high thermal conductivity, and low-cost interconnection materials. The traditional material technology of welding and wire bonding has low melting point, high temperature creep failure, wire winding, parasitic parameters and other unsolvable problems. New interconnect materials are developing from welding to sintering technology. By reducing the size of sintered particles and lowering the sintering temperature, nano-metal particle sintering technology has become the most promising technology among new interconnect materials for power semiconductor devices. [0003] At present, the advanced technology represented by nano-silver sintering has...

AI Technical Summary

Problems solved by technology

However, the patents, materials, processes and equipment of nano-silver sintering are mainly controlled by foreign manufacturers, and the domestic development is greatly restricted.

At the same time, nano-silver sintering technology also has shortcomings: 1) The price of silver material itself is relatively high, which limits its widespread use

2) The thermal expansion coefficients of silver and SiC chip backside materials are different, and other intermediate metal layers need to be added to improve interconnection performance, thereby increasing process complexity and cost

3) There is electromigration in the silver layer, which is not conducive to the long-term reliable application of power devices

Its disadvantages are: 1) Single-sized nano-metal particles, the copper paste made has a great possibility of producing large porosity during sintering; 2) Nano-metal particles are all prepared by chemical reduction, and the minimum size of the preparation is limited

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