Filter technologies implemented on CMOS image sensors for spectrally selective applications often use a combination of on-chip organic resists and an external substrate with multilayer dielectric coatings. The photopic-like and near-infrared bandpass filtering functions respectively required by ambient light sensing and user proximity detection through time-of-flight can be fully integrated on chip with multilayer metal–dielectric filters. Copper, silicon nitride, and silicon oxide are the materials selected for a technological proof-of-concept on functional wafers, due to their immediate availability in front-end semiconductor fabs. Filter optical designs are optimized with respect to specific performance criteria, and the robustness of the designs regarding process errors are evaluated for industrialization purposes.
© 2014 Optical Society of America
Original Manuscript: March 18, 2014
Revised Manuscript: May 16, 2014
Manuscript Accepted: May 29, 2014
Published: July 8, 2014
Laurent Frey, Lilian Masarotto, Patrick Gros D’Aillon, Catherine Pellé, Marilyn Armand, Michel Marty, Clémence Jamin-Mornet, Sandrine Lhostis, and Olivier Le Briz, "On-chip copper–dielectric interference filters for manufacturing of ambient light and proximity CMOS sensors," Appl. Opt. 53, 4493-4502 (2014)