Method and system for wafer backside alignment
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsSheng-Chieh Liu, Chia-Hung Kao, Tzu-Yang Wu, Sheng-Liang Pan, Yuan-Bang Lee
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Abstract
Disclosed is a method and a system for wafer backside alignment. A zero mark patterning on front side of a substrate. A plurality of layers are deposited on the front side of the substrate. The wafer is flipped over with backside of the substrate facing up, and a through wafer etching is performed from the backside to an etch stop layer deposited over the front side of the substrate.
Claims18
A method of performing backside alignment of a wafer, the method comprising:
- performing zero mark patterning on front side of a substrate;
- depositing a plurality of layers on the front side of the substrate, wherein the depositing a plurality of layers includes:
- depositing an etch stop layer over the zero mark patterning;
- and
- depositing a reflective layer over the etch stop layer, wherein the reflective layer includes a pattern defined by the zero mark patterning;
- and
- flipping the wafer over with backside of the substrate facing up;
- and
- etching through the substrate from the backside of the substrate to expose the zero mark patterning.
A method of performing backside alignment of a wafer, the method comprising:
- performing zero mark patterning on front side of a substrate;
- depositing a plurality of layers on the front side of the substrate, wherein depositing a plurality of layers on the front side of the substrate comprises;
- depositing an etch stop layer over the front side of the substrate;
- depositing an etch stop over the backside of the substrate to form a backside hard mask;
- and
- depositing a reflective layer over the etch stop layer on the front side of the substrate;
- flipping the wafer over with backside of the substrate facing up;
- and
- performing a through wafer etch of the substrate;
- wherein performing a through wafer etch of the substrate comprises:
- exposing a backside pattern opposite to a zero mark of the front side using a photo clear-out mask;
- etching away the backside hard mask using an oxide etcher;
- and
- etching the substrate from the backside to the etch stop layer over the front side of the substrate using a deep reactive ion etch silicon etcher.
A method of performing backside alignment of a wafer, the method comprising:
- patterning a zero mark on a front side of a substrate;
- depositing an etch stop layer over the patterned mark on the front side of the substrate;
- depositing a reflective layer over the etch stop layer on the front side of the substrate;
- flipping the wafer over with backside of the substrate facing up;
- and
- etching the substrate from the backside of the wafer, wherein the etching exposes the etch stop layer deposited on the front side of the substrate, wherein the etching includes:
- exposing a backside pattern opposite to a zero mark of the front side using a photo clear-out mask;
- and
- using the backside pattern to etch the substrate from the backside to the etch stop layer over the front side of the substrate.
Dependencies are inferred from the claim text.