We explore the feasibility of a controllable and easy-to-implement moire-based composite circular-line gratings imaging scheme for optical alignment in proximity lithography. One circular grating and four line gratings located on both the mask alignment mark and wafer alignment mark are used to realize the coarse alignment and fine alignment respectively. The fundamental derivation of coarse alignment employing circular gratings and fine alignment employing line gratings are given. Any displacement of misalignment that occurs at the surface of two overlapped gratings can be sensed and determined through subsequent fringe phase analysis without the influence of the gap between the mask and the wafer or wafer process. The design and manufacture process of the alignment marks are presented. The experimental results validate and demonstrate the feasibility of the proposed approach. (C) 2015 Optical Society of America
Science & Technology
; Physical Sciences
; NANOIMPRINT LITHOGRAPHY
1.Southwest Univ Sci & Technol, Fac Informat & Engn, Mianyang 621010, Sichuan, Peoples R China 2.Robot Technol Used Special Environm Key Lab Sichu, Mianyang 621010, Sichuan, Peoples R China 3.S China Univ Technol, Sch Elect & Informat, Guangzhou 510640, Guangdong, Peoples R China 4.Chinese Acad Sci, Inst Opt & Elect, Chengdu 610209, Peoples R China 5.Xihua Univ, Sch Elect Engn & Elect Informat, Chengdu 610039, Peoples R China
Xu, Feng,Zhou, Shaolin,Hu, Song,et al. Moire fringe alignment using composite circular-line gratings for proximity lithography[J]. OPTICS EXPRESS,2015,23(16):20905-20915.