• Novel 8-inch wafer scale process for low-cost production of back side illuminated (BSI) imaging sensors

      Joshi, A.; Chiaverini, D.J.; Kashyap, S.; Madhugiri, V.; Patti, R.; Hong, S.; Lesser, M.; University of Arizona Steward Observatory (SPIE, 2021)
      An 8-inch wafer scale process was developed that provides low cost availability of back-side illuminated (BSI) imaging sensors. The process has been optimized to convert standard CMOS and CCD 6-inch or 8-inch wafers from front side illuminated (FSI) sensors to BSI sensors. The process successfully demonstrates wafer planarization, bow correction, bonding to carrier wafers, wafer thinning, re-planarization, anti-reflection coating, through silicon vias (TSVs) and back side metallization. Good wafer thinning control was obtained for a wide range of epi thicknesses varying from 4 microns to 15 microns. The thinner epi is optimized for UV and visible sensing while the thicker epi material is optimized for near-infrared (NIR) sensing. The processed wafers demonstrate backside passivation and anti-reflection (AR) coatings that optimize the QE performance in a variety of bands such as 200nm-300nm, 300nm-400nm and 400nm-900nm. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.