关键词: 氮化铝, 高温共烧陶瓷基板, 微流道, 激光加工, 化学铣切, 激光功率, 扫描速度

Abstract: AlN HTCC substrates had the advantages of high thermal conductivity and good thermal stability. Embedding micro flow channels in AlN substrates might significantly improve heat dissipation and reduce package thickness, but it was diffeeicult to precision machine small size, hard brittle AlN micro flow channels. Based on the heat dissipation requirements of an array power device, a research was conducted on the design of AlN embedded microchannels. In order to solve the problems of machining micro channels on AlN ceramic substrates, laser etching of AlN ceramic substrates was conducted, the effects of line etching thresholds and laser parameters on the size and morphology of line etching grooves on AlN ceramic substrates were explored, and a composite processing method of laser and chemical milling was proposed. The experimental results show that the power threshold of laser etching in line etching is positively correlated with the scanning speed. With the increase of laser power, the width of the line etching groove will be larger than the diameter of the light spot, resulting in excessive machining. The dimensional errors of the micro channel structure obtained by laser and chemical milling combined processing are less than 50 μm. The surface roughness values may reach 5.6 μm.

Key words: aluminum nitride(AlN), high-temperature co-fired ceramics(HTCC) substrate, microchannel, laser processing, chemical milling, laser power, scanning speed