Method of forming an image sensor having stress releasing structure

A method of forming a semiconductor structure comprising:

• forming a plurality of photosensitive elements in a semiconductor substrate;
• forming a seal ring region surrounding the plurality of pixel elements;
• forming a plurality of shallow trench isolation (STI) structures in the semiconductor substrate;
• forming a plurality of pad openings in the semiconductor substrate, wherein the plurality of pad openings exposes a first STI structure of the plurality of STI structures;
• forming a trench in the semiconductor substrate, wherein the trench exposes a second STI structure of the plurality of STI structures, and the trench completely surrounds the plurality of photosensitive elements;
• and
• depositing a passivation layer along sidewalls and bottom surfaces of the plurality of pad openings and the trench.

A method of forming a semiconductor structure comprising:

• forming a plurality of photosensitive elements in a semiconductor substrate;
• forming a plurality of shallow trench isolation (STI) structures in the semiconductor substrate;
• forming a plurality of pad openings in the semiconductor substrate, wherein the plurality of pad openings exposes a first STI structure of the plurality of STI structures;
• forming a trench in a seal ring region of the semiconductor substrate, wherein the trench exposes a second STI structure of the plurality of STI structures, and the trench completely surrounds the plurality of photosensitive elements, wherein the plurality of pad openings are between the trench and the plurality of photosensitive elements.