Chemical Wet Etching of Silicon Wafers from a Mixture of Concentrated Acids

Warpage on the backside of silicon wafer after thinning process is examined. The thinning process includes back-grinding (BG) and wet chemical etching (WCE). Results of wafer warpage were compared to sub-surface damage from Transmission Electron Microscopy (TEM) analysis and showed that sub-surface damage on the backside of the silicon 100 would induce high wafer warpage, and reduced wafer strength. Further studies from surface roughness and topography of each surface finish is obtained by Atomic Force Microscopy (AFM) and SEM show that low surface roughness is in accordance with smooth surface condition, which comes after the wet etching process.