Design and Implementation of Alignment Device for Proximity Lithography System

For the "jammed" core lithography process in the domestic chip manufacturing field, in order to improve its alignment technology maturity and equipment stability, this paper carried out hardware improvement and software innovation respectively from the two stages of pre-alignment and precision alignment. Furthermore, a high precision and high efficiency platform has been achieved. A combination of Fourier function fitting and least square method was realized to complete the positioning of wafer notch and center. Besides, combined with affine change technology, the feature points extracted by SIFT algorithm were screened by random sampling consistency algorithm, and then the homography matrix is deduced to directly calculate the position deviation and angle deviation, which are fed back to the motion control system for accurate control. Through many experiments, the pre-alignment time is less than 5s and the precision reaches 0.3μm.