Structure Of Dielectric Grid For A Semiconductor Device

A device comprising:

• a substrate having a non-pixel region adjacent to a pixel region;
• a plurality of sensor elements disposed at a front surface of the substrate in the pixel region, the plurality of sensor elements being operable to sense radiation projected towards a back surface of the substrate;
• a dielectric grid disposed over the back surface of the substrate in the pixel region, wherein the dielectric grid includes:
• a metal pillar as its low portion;
• and
• a dielectric layer as its upper portion, wrapping around the metal pillar;
• a first dielectric trench between two adjacent dielectric grids;
• a second dielectric trench over the back surface of the substrate in the non-pixel region;
• and
• a plurality of color filters and microlenses disposed over the first dielectric trench and aligned with respective sensor elements.

A method comprising:

• providing a substrate having a pixel region and a non-pixel region adjacent to the pixel region, wherein a plurality of sensor elements are disposed in the pixel region;
• depositing an anti-reflection coating (ARC) layer over the substrate;
• depositing a buffer layer over the ARC layer;
• depositing a metal layer over the buffer layer;
• etching the metal layer through a first patterned mask layer to form metal pillars in the pixel region and a metal shield layer in the non-pixel region;
• depositing a dielectric layer over the metal pillar and the metal shield layer;
• etching the dielectric layers through a second mask to form a dielectric grid, including wrapping around the metal pillar in the pixel region and dielectric trenches over the metal shield layer in the non-pixel region;
• and
• forming a color filter and a microlens over the substrate, aligning with the respective sensor elements.