US 11,670,662 B2
Semiconductor substrate with passivated full deep-trench isolation and associated methods of manufacture
Cynthia Sun Yee Lee, Santa Clara, CA (US); and Shiyu Sun, Cupertino, CA (US)
Assigned to OmniVision Technologies, Inc., Santa Clara, CA (US)
Filed by OmniVision Technologies, Inc., Santa Clara, CA (US)
Filed on Dec. 23, 2020, as Appl. No. 17/133,553.
Prior Publication US 2022/0199658 A1, Jun. 23, 2022
Int. Cl. H01L 27/146 (2006.01)
CPC H01L 27/1463 (2013.01) [H01L 27/1462 (2013.01); H01L 27/14645 (2013.01); H01L 27/14685 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for forming an image sensor with passivated full deep-trench isolation, comprising:
forming a plurality of trenches in a front surface of a semiconductor substrate, each of the plurality of trenches having a trench depth;
filling the plurality of trenches with a sacrificial material;
forming a plurality of photodiode regions in the semiconductor substrate, each pair of adjacent photodiode regions being separated by a trench of the plurality of trenches;
forming a circuit layer disposed on the front surface of the semiconductor substrate; and
thinning the semiconductor substrate by removing material from a back surface of the semiconductor substrate until the semiconductor substrate has a thickness less than the trench depth, the back surface being opposite the front surface; and
removing the sacrificial material.