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.
© 2001 Optical Society of America
(220.1140) Optical design and fabrication : Alignment
(220.3740) Optical design and fabrication : Lithography
(220.4000) Optical design and fabrication : Microstructure fabrication
(350.3950) Other areas of optics : Micro-optics
Matthias Gruber, Detlev Hagedorn, and Werner Eckert, "Precise and Simple Optical Alignment Method for Double-Sided Lithography," Appl. Opt. 40, 5052-5055 (2001)