BSI chip with backside alignment mark
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChih Wei Sung, Chung-Bin Tseng, Keng-Ying Liao, Yen-Jou Wu, Po-Zen Chen, Su-Yu Yeh, Ching-Chung Su
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Abstract
A method includes forming image sensors in a semiconductor substrate. A first alignment mark is formed close to a front side of the semiconductor substrate. The method further includes performing a backside polishing process to thin the semiconductor substrate, forming a second alignment mark on the backside of the semiconductor substrate, and forming a feature on the backside of the semiconductor substrate. The feature is formed using the second alignment mark for alignment.
Claims20
A method comprising:
- forming image sensors in a semiconductor substrate, wherein a first alignment mark is formed close to a front side of the semiconductor substrate;
- performing a backside polishing process to thin the semiconductor substrate;
- forming a second alignment mark on the backside of the semiconductor substrate;
- after the second alignment mark is formed, forming deep trench isolation regions extending from a back surface of the semiconductor substrate into the semiconductor substrate;
- and
- forming a feature on the backside of the semiconductor substrate, wherein the feature is formed using the second alignment mark for alignment.
A method comprising:
- forming Shallow Trench Isolation (STI) regions in a semiconductor substrate, wherein the STI regions comprise a first alignment mark;
- forming image sensors in the semiconductor substrate;
- performing a backside polishing process from a backside of the semiconductor substrate;
- forming a second alignment mark in the semiconductor substrate, wherein the second alignment mark is formed by using the first alignment mark for aligning;
- etching the semiconductor substrate from the backside of the semiconductor substrate by using the second alignment mark for aligning;
- and
- forming color filters on the backside of the semiconductor substrate.
A method comprising:
- forming a plurality of Shallow Trench Isolation (STI) regions in a semiconductor substrate, wherein the STI regions comprise:
- an STI grid;
- a STI pad;
- and
- a first alignment mark;
- forming image sensors in the STI grid;
- and
- forming a second alignment mark from a backside of the semiconductor substrate, wherein the second alignment mark is formed by aligning to the first alignment mark.
Dependencies are inferred from the claim text.