Chinese Journal of Lasers, Volume. 39, Issue 9, 909001(2012)
Alignment Scheme Research Based on Equivalent Overlapped Gratings for Reflective Lithography Alignment
According to the technology characteristics of proximity and contact lithography, a practical reflective lithography alignment scheme is proposed. The differential Moiré fringe alignment technology is adopted in the scheme and alignment signal is carried in phase of Moiré fringe. Two sets of grating marks with placed oppositely direction and similar periods are designed on the mask and wafer, respectively. Charge coupled device imaging system is used to receive Moiré fringe image. Then, the relative position relationship can be obtained using Fourier transform to extract Moiré fringe phase. The designed marks could also detect position offset on the vertical and horizontal directions. The reasonable designed scheme of optical path is schematically given, the internal mechanism of the whole system alignment is analyzed in details, and the feasible mathematical model is established. This research results show that the maximum error is less than 0.002 pixel when alignment offset is less than 1 pixel. Compared with light path of transmission-type, the scheme is more practical, satisfying the requirements of the practical alignment.
Get Citation
Copy Citation Text
Zhu Jiangping, Hu Song, Yu Junsheng, Tang Yan, Zhou Shaolin, Liu Qi, He Yu. Alignment Scheme Research Based on Equivalent Overlapped Gratings for Reflective Lithography Alignment[J]. Chinese Journal of Lasers, 2012, 39(9): 909001
Category: holography and information processing
Received: Apr. 20, 2012
Accepted: --
Published Online: Jul. 4, 2012
The Author Email: Jiangping Zhu (zsyioe@163.com)