Double patterning techniques for forming a deep trench isolation structure

A method, comprising:

• forming a first portion of a pattern in a first direction in a hard mask layer over a substrate;
• forming, subsequent to forming the first portion of the pattern, a second portion of the pattern in a second direction in the hard mask layer;
• etching, based on the first portion and the second portion of the pattern, the substrate to form a plurality of intersecting trenches in the substrate;
• and
• filling the plurality of intersecting trenches to form a deep trench isolation (DTI) structure in the substrate.

A method, comprising:

• forming a plurality of photodiodes in a substrate of a pixel array for pixel sensors of a pixel array;
• forming, by a double patterning technique, a plurality of trenches in the substrate,
• wherein the plurality of trenches are formed in between the plurality of photodiodes, and
• wherein the plurality of trenches include a first subset of trenches and a second subset of trenches, and
• wherein the first subset of trenches and the second subset of trenches are approximately perpendicular;
• filling the plurality of trenches to form a deep trench isolation (DTI) structure in the substrate;
• forming a dielectric layer over the substrate, over the DTI structure, and over the photodiodes;
• forming a metal layer over the dielectric layer;
• etching through the metal layer and into a portion of the dielectric layer to form a grid structure;
• forming color filter regions for the pixel sensors in between the grid structure;
• and
• forming a micro-lens layer of the pixel array over the grid structure and over the color filter regions.