压力传感器中的各向异性腐蚀技术

Anisotropic etching during fabrication of si-based piezoresistive pressure sensors

研究了半导体压阻式压力传感器制作中的关键工艺———硅各向异性腐蚀.采用两种腐蚀液:m(TMAH)∶V(H2O)=50g∶50ml和m(KOH)∶V(IPA)∶V(H2O)=50g∶15ml∶35ml,在80～85℃腐蚀,均获得了较为理想的效果.制作的1MPa多晶硅压力传感器的输出线性度、迟滞和重复性分别约为0.06%、0.02%和0.02%.

A key process during fabrication of semiconductor piezoresistive pressure sensors, silicon anisotropic etching, is discussed. TMAH (tetramethylammonium hydroxide) water solution and KOH with IPA (isopropyl alcohol) mixed system can both get good etching result at 80°C-85°C. The compositions of two enchants are TMAH: H2O = 50 g: 50 ml and KOH: IPA: H2O = 50 g: 15 ml: 35 ml respectively. The linearity error of polysilicon piezoresistive pressure sensors made by such technology can reach 0.06%. The hysteresis and the repeatability are both about 0.02%.