Pad structure for front side illuminated image sensor

An integrated circuit, comprising:

• a plurality of metal interconnect layers arranged within a dielectric structure over a semiconductor substrate;
• a passivation structure arranged over the dielectric structure and having a recess arranged within an upper surface of the passivation structure, wherein the recess is defined by sidewalls of the passivation structure connecting the upper surface of the passivation structure to a horizontally extending surface of the passivation structure arranged between the sidewalls;
• a bond pad arranged within the recess, wherein the bond pad comprises one or more protrusions extending outward from a lower surface of the bond pad through openings in the horizontally extending surface to vertically contact one of the plurality of metal interconnect layers;
• and
• an upper passivation layer disposed over an uppermost surface of the passivation structure, an uppermost surface of the bond pad, and the sidewalls of the passivation structure defining the recess, wherein the upper passivation layer has a ‘U’ shaped segment located within the bond pad.

An integrated chip, comprising:

• a plurality of metal interconnect layers arranged within a dielectric structure over a topmost surface of a semiconductor substrate;
• a passivation structure separated from the semiconductor substrate by the dielectric structure, wherein the passivation structure contacts one or more of the plurality of metal interconnect layers;
• a bond pad disposed within a recess in the passivation structure, wherein the bond pad comprises one or more protrusions extending outward from a lower surface of the bond pad through the passivation structure to vertically contact one of the plurality of metal interconnect layers;
• and
• an upper passivation layer having one or more lower surfaces arranged directly over a topmost surface of the passivation structure and over a topmost surface of the bond pad, wherein the upper passivation layer further comprises a sidewall that is directly between a sidewall of the bond pad and a sidewall of the passivation structure facing the bond pad.