A Measurement System for Step Imprint Lithography
A precision 6-degree-of-freedom measurement system has been developed for simultaneous on-line measurements of imprint lithography stage. To successfully accomplish nanometer-scale pattern transfer from mold to resist film on the wafer, two types of positioning methods, static and dynamic, are used in this system. Two laser interferometers, two optical reflection mirrors and special structure on the stage with 3 elastic tracks are employed in this system to detect the positions and rotations of the stage. Through an algorithm, measurements of pitch, yaw and roll motions can be achieved. This system can realize on-line position detecting. Based on adjusting of PZTs, the detecting precision can reach 10nm and ±3 milli-arcsec, respectively. The measuring range can reach 100mm and ±10 arcsec, respectively.
Yongsheng Gao, Shuetfung Tse and Wei Gao
H.Z. Liu et al., "A Measurement System for Step Imprint Lithography", Key Engineering Materials, Vols. 295-296, pp. 107-112, 2005