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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/1651
- Optimisation of SU-8 processing parameters for deep X-ray lithography
- Barber, R. L.; Divan, R.; Ghantasala, M. K.; Harvey, Erol C.; Mancini, D. C.; Vora, Kaushal D.
- The negative photoresist SU-8 has been recognised as an unique resist, equally useful for conventional UV lithography as well as deep X-ray lithography (DXRL) applications [2, 7, 12, 17, 18]. One of the major limitations in the use of SU-8 in lithographic processes is the occurrence of internal stress . The processing parameters investigated for DXRL of SU-8 included resist thickness (450–850 µm), soft bake time (7–11 h), exposure dose (30–70 J/cm3), post exposure bake time (20, 40, 60 min) and development time. The effect of these parameters on stress was evaluated using wafer curvature measurements. Taguchi optimisation techniques have been used to asses the contribution of these parameters on the stress of the developed structures. This study shows that softbake time contributes the most to stress in the SU-8 film at 50%, followed by the exposure dose and post exposure bake with 30% and 15% respectively. Stress varied somewhat linearly with thickness. At higher thickness, the deposition process needs to be changed for very high aspect ratio structures. The main objective of this work has been to optimise the processing conditions of thick SU-8 films for DXRL. This paper was first presented at the High Aspect Ratio Microstructurres (HARMST) conference in Montery California, June 2003. This work was supported by the Australian Synchrotron Research Program, which is funded by the Commonwealth of Australia under the Major National Research Facilities Program. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, under Contract No. W-31-109-Eng-38. Support received from CRC for microTechnology (Australia) is also gratefully acknowledged. We also thank Dr. Brett Sexton and Fiona Smith from CSIRO (Australia), Dr. Francesco DeCarlo , Dr. Chian Liu, and Judy Yaeger from APS, and Dr. Jason Hayes and Dr. Matthew Solomon from Swinburne University for useful discussions and their help during some experimental work.
- Publication type
- Journal article
- Research centre
- Swinburne University of Technology. Faculty of Engineering and Industrial Sciences
- Microsystem Technologies, Vol. 11, no. 4-5 (2005), pp. 303-310
- Publication year
- Springer-Verlag Berlin
- Publisher URL
- Copyright © Springer-Verlag 2005..
- Peer reviewed