CD Sensitivity to Process Parameters in Photomask Fabrication Using a LASER Pattern Generator
Abstract
The control of critical dimension is very important for photomask fabrication. This paper describes the critical dimension (CD) variability for fabricating photomasks using wet etching process when masks were written using 413 nm wavelength LASER pattern generator. The photomask fabrication involves three fundamental processes-exposure using LASER beam, development and etching. Experiments were conducted to observe how CD is affected by process parameters. The critical parameters are exposure energy, development time and etching time. For 2 µ CD [line width (LW)], the CD sensitivity to exposure energy was observed as 8.3 nm/mW for BF patterns and 5.6 nm/mW for DF patterns. The CD sensitivity for development time was 5 nm/s for both BF and DF patterns. The CD sensitivity to etch time was 8.3 nm/s for BF patterns and 5.6 nm/s for DF patterns.
Notes
Acknowledgements
The authors are grateful to Director, Solidstate Physics Laboratory, Delhi, Director PM (MED) and DG (MED & CoS) for encouragement.
References
- 1.B.G. Eynon Jr., B. Wu, Photomask Fabrication Technology, vol. 4 (McGraw Hill, New York, 2005)Google Scholar
- 2.S. Babin, Mask Writers: An Overview, in Handbook of Photomask Manufacturing Technology, ed. by S. Rizvi (Taylor & Francis, New York, 2005), p. 56Google Scholar
- 3.M.J. Bohan, H.C. Hamaker, W. Montgomery, Implementation and characterization of a DUV raster scanned mask pattern generation system. Proc. SPIE 4562, 16–37 (2002)ADSCrossRefGoogle Scholar
- 4.P.C. Allen, Laser scanning for semiconductor mask pattern generation. Proc. IEEE 90(10), 1653 (2002)CrossRefGoogle Scholar
- 5.J.R. Salgueiro, V. Moreno, J. Linares, Model of linewidth for laser writing on a photoresist. Appl. Opt. 41(5), 895–901 (2002)ADSCrossRefGoogle Scholar
- 6.P. Buck, B. Grenon, A comparison of wet and dry chrome etching with the CORE-2564. Proc. SPIE 2087, 42–49 (1993)ADSCrossRefGoogle Scholar
- 7.K.T. Park, K.Y. Lee, Application of dry etching process on high end Cr photomasks. Proc. SPIE 3412, 246–251 (1998)ADSCrossRefGoogle Scholar
- 8.S.A. Rizvi, Mask Processing, in Handbook of Photomask Manufacturing Technology, ed. by S. Rizvi (Taylor & Francis, New York, 2005), p. 370CrossRefGoogle Scholar
- 9.G. Ruhl, R. Dietrich, R. Ludwig, Optimizing the chromium dry etch process. Semicond. Int. 7(1) (2001)Google Scholar
- 10.B. Wu, Photomask plasma etching: a review. J. Vac. Sci. Technol. B 24(1), 1–15 (2006)CrossRefGoogle Scholar