Permanent Bonding Process Development Using Gapless Glue for CIS-TSV Wafer Level Packaging

Permanent bonding of glass wafer with cavity wall (CW) and sensor wafer is the key technology for CMOS Image Sensor (CIS) wafer level packaging. But such bonding approach encounters unacceptable delamination issue when experiencing automotive reliability stress. To satisfy the increasing higher reliability requirement, a non-cavity permanent bonding process using gapless glue is developed. The bonding glue shows a good transmittance (>99%) for 400nm light wavelength. After wafer level packaging with via last TSV (through silicon via) technology, the imaging sensor packages pass all automotive reliability tests.