Deep etching process improvement of comb structure
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 SF6 and C4F8 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 4.5 μm,depth of 70 μm,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.
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维普
