<200 nm Wafer-to-Wafer Overlay Accuracy in Wafer Level Cu/SiO_2 Hybrid Bonding for BSI CIS

摘要

Sub 200 nm wafer-to-wafer (w2w) overlay accuracy on the entire 300 mm wafer was successfully demonstrated via wafer level Cu/SiO_2 hybrid bonding. Cu bonding pads relevant for back-side illuminated (BSI) complementary metal oxide semiconductor (CMOS) image sensor (CIS) were used for the experiment. Further, a crucial component to improve the overlay accuracy, namely the overlay model which identifies systematic alignment errors, was described.