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

摘要： 氮化铝（AlN）高温共烧陶瓷（HTCC）基板具有热导率高、热稳定性好等优点，在氮化铝基板中嵌入微流道可以大幅提高散热能力并减小封装厚度，但小尺寸、硬脆性氮化铝微流道精密加工难度较高。基于某阵列功率器件的散热需求，开展了氮化铝嵌入式微流道设计研究；为解决氮化铝陶瓷基板微流道加工难题，开展激光刻蚀氮化铝陶瓷工艺研究，探索氮化铝陶瓷基板的线刻蚀阈值及激光参数对线刻蚀槽尺寸和形貌的影响规律，并提出了激光与化学铣切的复合加工方法。实验结果表明：线刻蚀中激光刻蚀的功率阈值与扫描速度成正相关；随着激光功率的增大，线刻蚀槽宽度将大于光斑直径，会造成过度加工；激光与化学铣切复合加工得到的微流道结构尺寸精度误差均小于50 μm，表面粗糙度可以达到5.6 μm。

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