CSI with controllable isolation structure and methods of manufacturing and using the same

A method of manufacturing an image sensing integrated circuit device, the method comprising:

• providing a semiconductor substrate including a first side, a second side, a pixel region, and a peripheral region;
• forming photodiodes in an array in the pixel region;
• thinning the semiconductor substrate from the second side;
• forming a grid of trenches in the second side, wherein the grid comprises segments that extend between adjacent photodiodes in the array;
• filling the trenches, wherein filling the trenches comprises depositing a conductive material in the trenches so that the conductive material forms an in-substrate metal grid;
• forming a dielectric layer over the in-substrate metal grid;
• and
• forming an opening in the dielectric layer, wherein the in-substrate metal grid is exposed through the opening;
• and
• depositing a metal layer, wherein depositing the metal layer fills the opening and simultaneously creates a via intersecting the in-substrate metal grid, a contact pad on the second side, a conductive bridge extending from the via to the contact pad on the second side, and a back side metal grid over the dielectric layer in the pixel region, wherein the back side metal grid is formed above the in-substrate metal grid.

A method of manufacturing an image sensing integrated circuit device, the method comprising:

• providing a semiconductor substrate including a first side, a second side, a pixel region, and a peripheral region;
• forming photodetector pixels in an array in the pixel region;
• thinning the semiconductor substrate from the second side;
• forming an isolation structure that extends between adjacent pairs of the photodetector pixels and comprises an in-substrate metal grid;
• and
• forming a dielectric layer over the isolation structure;
• forming a first opening in the dielectric layer, wherein the in-substrate metal grid is exposed through the opening;
• and
• depositing a metal layer, wherein depositing the metal layer fills the first opening and simultaneously creates, a contact pad in the peripheral region on the second side, a via intersecting the in-substrate metal grid, and a conductive bridge extending from the via to the contact pad,
• wherein the in-substrate metal grid is coupled to the contact pad so that a voltage on the in-substrate metal grid is continuously variable with a voltage on the contact pad;
• and
• the in-substrate metal grid is electrically isolated from a ground voltage of the semiconductor substrate.