A Highly Reliable Back Side Illuminated Pixel against Plasma Induced Damage

Plasma process interaction with BSI image sensor is for the first time analyzed. The dark current degradation is modulated by the nature of the anti-reflective layer used at the backside interface. Three ARC stacks are compared by measuring the charge and the interface state density. Due to their negative charge even after plasma, the stacks based on metal oxides present a better hardiness than Oxide-Nitride stack, for a n-type pixel. Al ₂ O ₃ provides the best passivation, allowing a reliable BSI image sensor against plasma damage.