Image sensor with reduced optical path

An image sensor, comprising:

• a photodiode array comprising a first photodiode and a second photodiode overlapping a substrate;
• a first oxide layer overlapping the first photodiode, the second photodiode, and a portion of the substrate between the first photodiode and the second photodiode;
• a filler grid comprising a first filler grid structure and a second filler grid structure overlapping the first oxide layer;
• a metal grid comprising a first metal grid structure between the first filler grid structure and the second filler grid structure, wherein the first metal grid structure is in contact with a top surface of the first oxide layer;
• an oxide grid comprising a first oxide grid structure between the first filler grid structure and the second filler grid structure, wherein the first oxide grid structure is in contact with a top surface of the first metal grid structure;
• a capping layer in contact with the top surface of the first oxide layer;
• and
• a lens structure overlapping the first oxide grid structure, wherein there is no metal between a top surface of the first oxide grid structure and the lens structure.

An image sensor, comprising:

• a photodiode array in contact with a substrate;
• a first oxide layer in contact with the photodiode array and overlapping the substrate;
• a metal grid comprising a first metal grid structure in contact with a top surface of the first oxide layer;
• an oxide grid comprising a first oxide grid structure in contact with a top surface of the first metal grid structure;
• a capping layer in contact with the top surface of the first oxide layer, the first metal grid structure, and the first oxide grid structure, wherein there is no metal between a top surface of the first oxide grid structure and a lens structure overlapping the first oxide grid structure;
• and
• a filler grid comprising a first filler grid structure in contact with the capping layer.