梳齿结构深刻蚀工艺改进

Deep etching process improvement of comb structure

梳齿型谐振式传感器对谐振器梳齿的形貌有很高的要求,需要梳齿侧壁很好的垂直度、粗糙度以及片间均匀性等。采用感应耦合等离子体(ICP)深硅刻蚀工艺对具有深宽比较大的梳齿结构进行深刻蚀研究。影响深硅刻蚀的主要因素包括SF_(6)和C_(4)F_(8)气体流量、腔室压力、刻蚀与钝化保护时间、下基板功率等工艺参数,着重研究了片间均匀性、垂直度、粗糙度等影响结构性能的几个方面,得到了宽4.5μm、深70μm的梳齿结构,垂直度为89.7°,侧壁粗糙度46 nm,均匀性1.2%的优化工艺,为高精度MEMS梳齿型传感器的制作提供了基础。

Comb-type resonant sensors have high demands on the morphology of the resonator combs,good perpendicularity,roughness and interchip uniformity of the comb sidewalls are required.Inductively coupled plasma(ICP)deep silicon etching process is used for deep etching research on comb structure with large depth-to-width ratio.The main factors affecting deep silicon etching include SF_(6) and C_(4)F_(8) gas flow,chamber pressure,etching and passivation protection time,lower substrate power and other process parameters,this research focuses on several aspects which affect structural properties such as inter-slice uniformity,perpendicularity,roughness,etc.An optimized process by which a comb structure with width of 4.5μm,depth of 70μm,and with perpendicularity of 89.7°,sidewall roughness of 46 nm and uniformity of 1.2%is obtained,which provides the basis for the fabrication of high-precision MEMS comb-type sensors.