外文题目: Image grating metrology using phase-stepping interferometry in scanning beam interference lithography
作者: Li, Minkang; Zhou, Changhe; Wei, Chunlong; Jia, Wei; Lu, Yancong; Xiang, Changcheng; Xiang, XianSong
刊名: Proc.SPIE
来源图书: HOLOGRAPHY, DIFFRACTIVE OPTICS, AND APPLICATIONS VII
年: 2017 卷: 10022 文章编号：1002212
会议名称: Conference on Holography, Diffractive Optics, and Applications VII
英文关键词:
scanning beam interference lithography; phase-stepping interferometry; laser interferometer; image grating; phase unwrapping
FABRICATION
英文摘要:
Large-sized gratings are essential optical elements in laser fusion and space astronomy facilities. Scanning beam interference lithography is an effective method to fabricate large-sized gratings. To minimize the nonlinear phase written into the photo-resist, the image grating must be measured to adjust the left and right beams to interfere at their waists. In this paper, we propose a new method to conduct wavefront metrology based on phase-stepping interferometry. Firstly, a transmission grating is used to combine the two beams to form an interferogram which is recorded by a charge coupled device(CCD). Phase steps are introduced by moving the grating with a linear stage monitored by a laser interferometer. A series of interferograms are recorded as the displacement is measured by the laser interferometer. Secondly, to eliminate the tilt and piston error during the phase stepping, the iterative least square phase shift method is implemented to obtain the wrapped phase. Thirdly, we use the discrete cosine transform least square method to unwrap the phase map. Experiment results indicate that the measured wavefront has a nonlinear phase around 0.05 lambda@404.7nm. Finally, as the image grating is acquired, we simulate the print-error written into the photo-resist.


文献类型: 会议论文
正文语种: English
收录类别: ISTP
DOI: 10.1117/12.2245330


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