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 μm and the height of about 4 μm 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.

中文翻译：

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真空冷喷涂沉积窄薄铜线状图案及沉积行为模拟

与陶瓷材料相比，制造致密金属薄膜需要更高的真空冷喷涂（VCS）冲击速度，也称为气溶胶沉积方法。在这项研究中，设计了一种用于制造密集、细而窄的铜线的超音速喷嘴。通过CFD数值模拟研究了气体和铜颗粒的加速行为。并通过有限元分析研究了铜颗粒的冲击行为。宽约200μm、高约4μm的铜线在室温下直接制作在硅片上，无需掩膜。结果表明，粒子碰撞沉积系统中的冲击速度存在最佳粒子直径。为了在 VCS 中获得更高的粒子冲击速度，基板应置于气体激波高压区的后方，使自由射流高压区的位置与弓形激波与基板的位置尽可能重合。铜颗粒在撞击和随后的颗粒压实时经历塑性变形和颗粒变平。铜线的宽度随着间隔距离的增加而增加，最大高度随着间隔距离的增加而减少。