Silicon Partial Etch Defect Researches in BSI CMOS Image Sensor Process Product

To reduce ink die loss in BSI CMOS image sensor (CIS), silicon partial etch defect after etching during Backside Silicon Etch (BSSE) process is studied. In this research, the root cause of silicon partial etch defect is clarified and a defect improvement approach is proposed. By verifying the evolution of defects in the Backside Metal Grid (BMG) process step by step, it is shown that the queue time (Q-time) window plays an indispensable role in the formation of silicon partial etch defects. Here provides an effective solution for reducing silicon partial etch defects in BSSE, and gives a method to enlarge the BMG Q-time window.