Pixel sensor including a layer stack to reduce and/or block the effects of plasma processing and etching on the pixel sensor

A system, comprising:

• one or more semiconductor processing tools configured to:
• form a plurality of photodiodes in a substrate of a pixel array,
• wherein each of the plurality of photodiodes s associated with a respective pixel sensor included in the pixel array;
• form a first oxide layer over the plurality of photodiodes;
• form a silicon nitride layer directly on the first oxide layer,
• wherein a band gap of the silicon nitride layer is lower than a band gap of the first oxide layer;
• form a second oxide layer directly on the silicon nitride layer;
• form a grid structure over the second oxide layer;
• form a passivation liner over a top layer of the grid structure, on sidewalls of the grid structure, and on a portion of the second oxide layer;
• remove a first portion of the passivation liner from the second oxide layer;
• form a plurality of color filter regions in between portions of the passivation liner on the sidewalls of the grid structure and directly on a surface of the second oxide layer;
• and
• form a micro-lens layer over a second portion of the passivation liner and over the plurality of color filter regions,
• wherein the second portion of the passivation liner is over an entire portion of the top layer of the grid structure.

A method, comprising:

• forming a plurality of photodiodes between an isolation structure and in a substrate of a pixel array,
• wherein each of the plurality of photodiodes is associated with a respective pixel sensor included in the pixel array;
• forming a layer stack over the plurality of photodiodes and the isolation structure, wherein the layer stack comprises a first layer, a second layer directly on the first layer, and a third layer directly on the second layer, wherein the second layer comprises silicon nitride;
• forming a grid structure over a portion of the layer stack that is over the isolation structure,
• wherein the grid structure includes a tungsten layer;
• forming a passivation liner on a top of the grid structure, on sidewalls of the grid structure, and on a portion of the layer stack;
• removing a first portion of the passivation liner from the layer stack;
• forming a plurality of color filter regions in between portions of the passivation liner on the sidewalls of the grid structure and directly on a surface of the layer stack;
• and
• forming a micro-lens layer over a second portion of the passivation liner and over the plurality of color filter regions,
• wherein the second portion of the passivation liner is over an entire portion of the grid structure.