Optical blocking regions for pixel sensors

A method, comprising:

• forming, in a substrate, an isolation structure around at least one photodiode;
• patterning a portion of the substrate, corresponding to an optical blocking region, to form a recessed pattern;
• forming a dielectric layer over the isolation structure and over the portion of the substrate corresponding to the optical blocking region, wherein the dielectric layer conforms to the recessed pattern;
• and
• forming a metal layer over the dielectric layer, wherein the metal layer conforms to the recessed pattern in the optical blocking region.

A semiconductor device, comprising:

• at least one pixel sensor;
• and
• an optical blocking region, adjacent to the at least one pixel sensor, comprising:
• a substrate;
• a dielectric layer over the substrate and including a recessed pattern;
• and
• a metal layer, over the dielectric layer, conforming to the recessed pattern and configured to reflect light away from the at least one pixel sensor,
• wherein the metal layer additionally forms a metal grid over an isolation structure that at least partially surrounds at least one photodiode of the at least one pixel sensor.