29 January 2015 Gap-optimized Moiré phase imaging alignment for proximity lithography
Jiangping Zhu, Song Hu, Zhisheng You, Xianyu Su
Author Affiliations +
Abstract
The proposed four-quadrant Moiré alignment scheme to detect the misalignment between mask and wafer for proximity lithography can achieve the alignment accuracy with nanometer level. When implementing the scheme, however, the distribution of Moiré fringes associated with the mask–wafer gap indeed goes against the alignment, making the gap optimization highly urgent. The optimization model is established, and numerical simulation as well as experimental verification is also provided. Furthermore, an alignment accuracy of ∼3  nm with the illumination wavelength of 632.8 nm is experimentally attained. Simultaneously, the design mechanism of alignment marks for improving the availability of the alignment scheme is discussed.
© 2015 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2015/$25.00 © 2015 SPIE
Jiangping Zhu, Song Hu, Zhisheng You, and Xianyu Su "Gap-optimized Moiré phase imaging alignment for proximity lithography," Optical Engineering 54(1), 017105 (29 January 2015). https://doi.org/10.1117/1.OE.54.1.017105
Published: 29 January 2015
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CITATIONS
Cited by 3 scholarly publications.
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KEYWORDS
Optical alignment

Semiconducting wafers

Photomasks

Lithography

Phase imaging

Moire patterns

Image processing

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