Patent ID: 7485486

Claim:
A method of a fabricating a photodiode, comprising: (a) providing a substrate having a first semiconductor type surface region on at least a portion thereof; (b) implanting and thereby forming a second semiconductor type shallow surface layer into a portion of said surface region, wherein a photodiode region is formed by a pn-junction of the first semiconductor type surface region and the second semiconductor type shallow surface layer; (c) forming a multi-layer anti-reflective coating (ARC) on said shallow surface layer, wherein said multi-layer ARC comprises a thin oxide layer on said shallow surface layer and a second dielectric layer different from said thin oxide layer on said thin oxide layer; (d) forming an etch stop on said second dielectric, wherein said etch stop comprises at least one layer resistant to oxide etch; (e) forming at least one oxide comprising layer on said etch stop; (f) removing, down to said first semiconductor type surface region, at least a portion of said ARC, a portion of said etch stop and a portion of said at least one oxide comprising layer that are not above said photodiode region; (g) after step (f), performing at least some of interlayer dielectric (ILD) processing, metal processing, contact processing, via processing and passivation processing, which results in multiple layers being formed above said at least one oxide comprising layer; (h) removing at least a portion of said multiple layers formed at step (g) so that an opening down to said etch stop is provided over at least a portion of said photodiode region, wherein step (h) includes removing at least a portion of said at least one oxide comprising layer formed at step (e) using an oxide etch; and (i) removing at least a portion said etch stop that is over said photodiode region to expose to ambient at least a portion of said ARC that is over said photodiode region.