Back side illuminated image sensor with deep trench isolation structures and self-aligned color filters

A method of fabricating a semiconductor image sensor device, comprising:

• providing a substrate that contains a plurality of radiation-sensing regions formed therein, the substrate having a first side and a second side;
• bonding the first side of the substrate to a carrier substrate;
• thinning the substrate from the second side after the bonding;
• forming a dielectric layer over the second side of the substrate after the thinning;
• forming a plurality of trenches from the second side, the trenches extending through the dielectric layer and at least partially through the substrate;
• forming a plurality of isolation structures in the trenches, including filling the trenches with a material that reflects radiation and performing a polishing process to the material until portions of the material filling the trenches are co-planar with the dielectric layer;
• and
• thereafter removing at least a portion of the dielectric layer such that portions of the isolation structures protrude out of the dielectric layer.

A method of fabricating a semiconductor image sensor device, comprising:

• forming a plurality of layers over a substrate that includes a plurality of radiation-sensing elements;
• forming a trench that extend through the plurality of layers and at least partially into the substrate, wherein the trench is located between a pair of adjacent radiation-sensing elements;
• filling the trench with a radiation-reflective material;
• and
• performing an etching process to partially remove a topmost layer of the plurality of layers so that a segment of the radiation-reflective material filling the trench is exposed.