Self-aligned isolation structures and light filters

An imaging system, the imaging system comprising:

• a semiconductor layer including a plurality of photodiodes, wherein the plurality of photodiodes is arranged into an array, and wherein the semiconductor layer has a front side and a back side;
• a plurality of isolation structures disposed in the back side of the semiconductor layer between individual photodiodes in the plurality of photodiodes, wherein the plurality of isolation structures extends into the back side of the semiconductor layer a first depth and extends out of the back side of the semiconductor layer a first length;
• and
• a plurality of light filters disposed proximate to the back side of the semiconductor layer, wherein the plurality of isolation structures is disposed between individual light filters in the plurality of light filters.

A method of image sensor fabrication, the method comprising:

• forming a plurality of photodiodes in a semiconductor layer, wherein the semiconductor layer has a front side and a back side;
• forming a plurality of isolation structures in the back side of the semiconductor layer;
• wherein individual isolation structures in the plurality of isolation structures are disposed between individual photodiodes in the plurality of photodiodes, and wherein the plurality of isolation structures extend into the back side of the semiconductor layer a first depth and extend out of the back side of the semiconductor layer a first length;
• depositing an antireflection coating on the semiconductor layer;
• forming a plurality of light filters disposed proximate to the back side of the semiconductor layer, wherein the plurality of isolation structures is disposed between individual light filters in the plurality of light filters.