High aspect ratio back side deep trench isolaton structure with substrate-embedded metal grid and no pinch off

An image sensor comprising:

• a semiconductor substrate including a first side and a second side;
• photodetectors arrayed within the semiconductor substrate;
• a passivation layer over the second side;
• a deep trench isolation structure extending into the semiconductor substrate between the photodetectors from the second side;
• and
• a metal grid comprising segments extending through the passivation layer and into the semiconductor substrate to form a part of the deep trench isolation structure, wherein the segments undergo a step change in width proximate the second side.

An image sensor comprising:

• a semiconductor substrate including a first side and a second side;
• photodetectors arrayed within the semiconductor substrate;
• a passivation layer over the second side;
• a deep trench isolation structure extending into the semiconductor substrate and between the photodetectors from the second side;
• and
• a metal grid comprising segments extending through the passivation layer and into the semiconductor substrate to form a part of the deep trench isolation structure, wherein the metal grid is misaligned with the deep trench isolation structure.