Patent ID: 7416912

Claim:
A method of fabricating a CMOS image sensor, comprising; forming, in a semiconductor substrate divided into a photodiode region and a pad region, a plurality of photodiodes in the photodiode region; fanning a first insulating layer over the semiconductor substrate including the photodiodes; forming a metal pad on the first insulating layer in the pad region; forming a second insulating layer over the semiconductor substrate including the metal pad; forming a mask layer on the second insulating layer, to expose portions of the second insulating layer over the metal pad and the photodiodes, respectively; etching the exposed portions of the second insulating layer to form simultaneously a pad opening in the pad region and a trench in the photodiode region; selectively etching portions of the second insulating layer and the first insulating layer under the trench with an etchant under conditions providing an etch selectivity ratio with respect to the metal pad; and forming a slope on lateral sides of at least the second insulating layer, wherein forming the slope comprises forming a high-density plasma oxide layer over the semiconductor substrate including the pad opening in the pad region and the trench in the photodiode region, and then removing the high-density plasma oxide layer.