US Patent 8975668 Backside-thinned image sensor using Al

A structure and method of manufacture is disclosed for a backside thinned imager that incorporates a conformal, Al2O3, low thermal budget, surface passivation. This passivation approach facilitates fabrication of backside thinned, backside illuminated, silicon image sensors with thick silicon absorber layer patterned with vertical trenches that are formed by etching the exposed back surface of a backside-thinned image sensor to control photo-carrier diffusion and optical crosstalk. A method of manufacture employing conformal, Al2O3, surface passivation approach is shown to provide high quantum efficiency and low dark current while meeting the thermal budget constraints of a finished standard foundry-produced CMOS imager.