US 11,791,357 B2
Composite BSI structure and method of manufacturing the same
Wei Chuang Wu, Tainan (TW); Dun-Nian Yaung, Taipei (TW); Feng-Chi Hung, Chu-Bei (TW); Jen-Cheng Liu, Hsin-Chu (TW); Jhy-Jyi Sze, Hsin-Chu (TW); Keng-Yu Chou, Kaohsiung (TW); Yen-Ting Chiang, Tainan (TW); Ming-Hsien Yang, Taichung (TW); and Chun-Yuan Chen, Tainan (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu (TW)
Filed on Aug. 4, 2021, as Appl. No. 17/393,687.
Application 17/393,687 is a continuation of application No. 16/521,876, filed on Jul. 25, 2019, granted, now 11,211,419.
Claims priority of provisional application 62/764,964, filed on Aug. 15, 2018.
Prior Publication US 2021/0366956 A1, Nov. 25, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 27/146 (2006.01)
CPC H01L 27/1463 (2013.01) [H01L 27/1464 (2013.01); H01L 27/14603 (2013.01); H01L 27/14683 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An image sensor comprising:
a substrate;
a pixel sensor comprising a photodetector in the substrate;
a first trench isolation structure comprising a pair of first trench isolation segments, wherein the first trench isolation segments are respectively on opposite sides of the pixel sensor at a boundary of the pixel sensor and extend into a backside of the substrate to a first depth;
a second trench isolation structure extending into the backside of the substrate to a second depth less than the first depth between the first trench isolation segments; and
an absorption enhancement structure overlying the photodetector between the first trench isolation segments, wherein the absorption enhancement structure is recessed into the backside of the substrate and has a sidewall directly contacting the second trench isolation structure.