System and method for alignment in semiconductor device fabrication
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd., ("TSMC")
InventorsYen-Liang Chen, Te-Chih Huang, Chen-Ming Wang, Chih-Ming Ke, Tsai-Sheng Gau
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Abstract
A method of determining overlay error in semiconductor device fabrication includes receiving an image of an overlay mark formed on a substrate. The received image is separated into a first image and a second image, where the first image includes representations of features formed on a first layer of the substrate and the second image includes representations of the features formed on a second layer of the substrate. A quality indicator is determined for the first image and a quality indicator is determined for the second image. In an embodiment, the quality indicators include asymmetry indexes
Claims20
A method of determining overlay error in semiconductor device fabrication, the method comprising:
- receiving an image of an overlay mark formed on a substrate;
- separating the image into a first image and a second image, wherein the first image includes an image of features formed on a first layer of the substrate and the second image includes an image of the features formed on a second layer of the substrate;
- determining a quality indicator for the first image;
- and
- determining a quality indicator for the second image.
A method, comprising:
- providing a first overlay measurement map and a first quality indicator map associated with a first overlay measurement scan of a substrate;
- providing a second overlay measurement map and a second quality indicator map associated with a second overlay measurement scan of the substrate, wherein the first and second overlay measurement scan differ in at least one process parameter;
- generate a virtual overlay map using the first and second quality indicator maps;
- calculate the similarity of each of the first and second overlay measurement maps to the virtual overlay map;
- select one of the first and second scan based on the calculation of similarity;
- and
- scan another substrate using the selected scan.
A system, comprising:
- a photolithography tool operable to form a mark on a substrate;
- an overlay metrology tool operable to generate an image of the mark;
- a process quality indicator generator system operable to receive the image of the mark and generate a process quality indicator;
- and
- a process control system operable to analyze the generated process quality indicator.
Dependencies are inferred from the claim text.