Patterned Fabry-Perot Filter Fabrication on Transparent wafer in 200 mm CMOS fab

Fabry-Perot (FP) filter is a stack to obtain narrowband spectral filtering of light at a certain wavelength range. Since the interest in optical filters is increasing in various applications, there is demand for developing filters on the various imagers. In this paper, we demonstrated the FP filter fabrication process on transparent wafer for imaging applications. The fabrication process includes opaquing the backside of quartz wafer to be able to handle wafers in process tools like Silicon wafers. We propose a new approach to align layers on quartz wafer to prevent the alignment mark recognition error by reflections through the quartz. We demonstrate a thick FP filter deposition and patterning of the optical filter stack. Furthermore, wafer bow during the fabrication is closely monitored and compensated to enable handling in 200 mm CMOS fab tools.