Share Email Print

Proceedings Paper

Real-time optical characterization of laser oxidation process in bimetallic direct write gray scale photomasks
Author(s): David K. Poon; Glenn H. Chapman; Chinheng Choo; Marian Chang; Jun Wang; Yuqiang Tu
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

DC-sputtered Sn/In and Bi/In bimetallic thin films oxidize and turn transparent under laser exposure. The film's transparency, or optical density (OD), changes smoothly with increasing laser power, from ~3.0OD (unexposed) to <0.22OD (fully exposed). Laser-induced oxidation of bimetallic films can be used to produce direct-write binary and analogue grayscale photomasks. In order to create high quality grayscale photomask and to improve our current laser writing process, requires real time measurement of OD values, and a greater understanding of the laser-induced oxidation process of the bimetallic thin films. An OD measurement system has been developed capable of providing real time optical density and exposure power changes for the bimetallic thin films. Three silicon-based PIN photodiodes were used to monitor the incident and transmitted beams powers, allowing us to measure the OD change as the film oxidizes, giving us a real time measure of the optical density changes of the bimetallic thin film. With this OD measurement system, real time OD data can be used to adjust the laser power to compensate any variations in laser output power, film characteristics and other variations in the laser writing system. Furthermore, with the incident beam focused, we can precisely measure OD level in areas as small as the laser spot size. Exposed Bi/In/O films show an immediate rapid -2OD/ms change in the first 0.5 ms of exposure. However, In/Sn and Zn films show an initial time delay before OD begins to change, and then a less rapid change of -0.56OD/ms or -0.32OD/ms respectively.

Paper Details

Date Published: 1 March 2006
PDF: 12 pages
Proc. SPIE 6106, Photon Processing in Microelectronics and Photonics V, 61060G (1 March 2006); doi: 10.1117/12.647251
Show Author Affiliations
David K. Poon, Simon Fraser Univ. (Canada)
Glenn H. Chapman, Simon Fraser Univ. (Canada)
Chinheng Choo, Simon Fraser Univ. (Canada)
Marian Chang, Simon Fraser Univ. (Canada)
Jun Wang, Simon Fraser Univ. (Canada)
Yuqiang Tu, Simon Fraser Univ. (Canada)

Published in SPIE Proceedings Vol. 6106:
Photon Processing in Microelectronics and Photonics V
David B. Geohegan; Tatsuo Okada; Craig B. Arnold; Frank Träger; Jan J. Dubowski; Michel Meunier; Andrew S. Holmes, Editor(s)

© SPIE. Terms of Use
Back to Top