The Challenges and Solutions to the Development of Light Shielding Mask Glass from Design Phase to Process Optimization for CMOS Image Sensors

This paper discusses the introduction of light shielding masks (LSM) in image sensor applications for glare reduction purpose, focusing on the challenges in the dicing process due to the uneven LSM surface. This paper focuses on a rectangular anti-reflective borosilicate glass and evaluates two LSM glass mounting methods: faced-up and faced-down. The faced-up method simplifies dicing but requires an extra glass transfer step, while the faced-down method avoids glass transfer step but increases the risk of chipping and cracks. Tape and blade selection are crucial. By using low-adhesion ultraviolet (UV) curable tapes avoids residue and resin blades offering ultra smooth dicing performance compared to metal blade. By optimizing cutting parameters through design of experiments (DOE), chipping size is controlled and a process capability index (Cpk) greater than 1.67 is achieved.