Narrow and Thin Copper Linear Pattern Deposited by Vacuum Cold Spraying and Deposition Behavior Simulation

Compared with ceramic materials, the fabrication of dense metal films requires higher impact velocity in vacuum cold spraying (VCS), also known as aerosol deposition method. In this study, a supersonic nozzle for the fabrication of dense, thin and narrow copper lines was designed. The acceleration behavior of gas and copper particles was investigated through CFD numerical simulation. And the impact behavior of copper particles was studied through finite element analysis. The copper lines with the width of about 200 mu m and the height of about 4 mu m were directly fabricated on silicon wafers at room temperature without masking. The results show that there is an optimum particle diameter for the impact velocity in particle collision deposition systems. In order to obtain a higher particle impact velocity in VCS, the substrate should be placed behind the high-pressure region of gas shock wave, so that the position of the high-pressure region of the free jet and the position of the bow shock with the substrate coincide as much as possible. Copper particles undergo plastic deformation and particle flattening upon impact and subsequent particle compaction. The width of copper line increased with increasing standoff distance, and maximum height decreased with increasing standoff distance.

Automated summary

A supersonic nozzle was designed to fabricate dense, thin, and narrow copper lines, and the acceleration behavior of gas and copper particles was investigated through CFD numerical simulation and finite element analysis. Copper lines were directly fabricated on silicon wafers at room temperature. Optimum particle diameter for impact velocity and positioning substrate behind high-pressure gas shock wave are crucial for achieving higher particle impact velocity in VCS.