Precise and simple optical alignment method for double-sided lithography.
A method for aligning a photolithographic mask at the top of a transparent wafer that has a pattern on its bottom side is presented. The method is based on optical self-imaging of special alignment marks and provides submicrometer accuracy. The method is simple and robust and can conveniently be implemented on laboratory mask aligners for contact or proximity printing.
Gruber
M
M
Hagedorn
D
D
Eckert
W
W