Experiment on anisotropic wet etching characteristics of sapphire
1. School of Mechanical Engineering, Southeast University, Nanjing, Jiangsu 210009， China； 2. School of Mechanical Engineering, Nanjing University of Vocational Industry Technology, Nanjing, Jiangsu 210023， China
Abstract：Due to the complex anisotropic etching characteristics of sapphire, it is difficult to predict and control the etching evolution process and results. The crystal etch rate anisotropy of sapphire was obtained at (245±3)℃ and V(98%H2SO4) ∶V(85%H3PO4) equal to 3 ∶1 by the singlecrystal sapphire hemisphere. The etching microstructural characteristics under typical mask shapes were compared and analyzed, and the relationship between the etch rates of crystal planes and forming planes of microstructures was explored. The results show that the overall etching rate distribution of sapphire presents typical trigonal symmetry and multiextreme pattern, and the etch rates of crystal planes near equator are extremely low. Using high concentration phosphoric acid as etching buffer can significantly reduce the generation of various microbumps in the etching process and effectively improve the quality of microstructure surface processing.
