TIP-OPC: a new topological invariant paradigm for pixel based optical proximity correction

ABSTRACT

As the 193nm lithography is likely to be used for 45mm and even 32nm processes, much more stringent requirement will be posed on Optical Proximity Correction (OPC) technologies. Currently, there are two OPC approaches --- the model-based OPC (MB-OPC) and the inverse lithography technology (ILT). MB-OPC generates masks which is less complex compared with IL.T. But IL.T produces much better results than MB-OPC in terms of contour fidelity because ILT is a pixel based method. Observing that MB-OPC preserves the mask shape topologies which leads to a lower mask complexity, we combine the strengths of both methods --- the topology invariant property and the pixel based mask representation. To the best of our knowledge, it is the first time that this topological invariant pixel based OPC (TIP-OPC) paradigm is proposed, which fills the critical hole of the OPC landscape and potentially has many new applications. Our technical novelty includes the lithography friendly mask topological invariant operations, the efficient Fast Fourier Transform based cost function sensitivity computation and the TIP-OPC algorithm. The experimental results show that TIP-OPC can achieve much better post OPC contours compared with MB-OPC while maintaining the mask shape topologies.

REFERENCES

• 1: N. B. Cobb and A. Zakhor, "Fast, low-complexity mask design," in Proc. SPIE 2440, May 1995, pp. 313--327.
• 2: N. B. Cobb, A. Zakhor, and E. Miloslavsky, "Mathematical and CAD framework for proximity correction," in Proc. SPIE 2726, Jun. 1996, pp. 208--222.
• 3: Nicolas Bailey Cobb , Avideh Zakhor, Fast optical and process proximity correction algorithms for integrated circuit manufacturing, University of California, Berkeley, 1998
• 4: N. Cobb and Y. Granik, "New concepts in OPC," in Proc. SPIE 5377, 2004, pp. 680--690.
• 5: C.-Y. Hung, B. Zhang, D. Tang, E. Guo, L. Pang, Y. Liu, A. Moore, and K. Wang, "First 65nm tape-out using inverse lithography technology (ILT)," in Proc. SPIE 5992, Nov. 2005, pp. 596--604.
• 6: Y. Liu, D. Abrams, L. Pang, and A. Moore, "Inverse lithography technology principles in practice: unintuitive patterns," in Proc. SPIE 5992, Nov. 2005, pp. 886--893.
• 7: Y. Granik, "Solving inverse problems of optical microlithography," in Proc. SPIE 5754, May 2005, pp. 506--526.
• 8: Y. Granik, "Fast pixel-based mask optimization for inverse lithography," Journal of Microlithography, Microfabrication and Microsystems, vol. 5, no. 4, p. 043002, Dec. 2006.
• 9: D. S. Abrams and L. Pang, "Fast inverse lithography technology," in Proc. SPIE 6154, Apr. 2006, pp. 534--542.
• 10: D. Van Den Broeke, M. Hsu, J. F. Chen, S. Hsu, U. Hollerbach, and T. Laidig, "Manufacturing implementation of IML#8482; technology for 45nm node contact masks," in Proc. SPIE 6283, Jun. 2006.
• 11: A. Poonawala and P. Milanfar, "Mask Design For Optical Microlithography --- An Inverse Imaging Problem," IEEE Trans. on Image Processing, vol. 16, no. 3, pp. 774--788, Mar. 2007.
• 12: L. Pang, Y. Liu, and D. Abrams, "Inverse Lithography Technology (ILT): what is the impact to the photomask industry?" in Proc. SPIE 6283, Jun. 2006.
• 13: A. Poonawala and P. Milanfar, "OPC and PSM design using inverse lithography: a nonlinear optimization approach," in Proc. SPIE 6154, Apr. 2006, pp. 1159--1172.
• 14: M. Born and E. Wolf, Principles of Optics : Electromagnetic Theory of Propagation, Interference and Diffraction of Light, 7th ed. Cambridge University Press, Oct. 1999.
• 15: Joydeep Mitra , Peng Yu , David Z. Pan, RADAR: RET-aware detailed routing using fast lithography simulations, Proceedings of the 42nd annual conference on Design automation, June 13-17, 2005, Anaheim, California, USA [doi>10.1145/1065579.1065678]
• 16: P. Yu, D. Z. Pan, and C. A. Mack, "Fast lithography simulation under focus variations for OPC and layout optimizations," in Proc. SPIE 6156, Apr. 2006, pp. 397--406.
• 17: Peng Yu , Sean X. Shi , David Z. Pan, Process variation aware OPC with variational lithography modeling, Proceedings of the 43rd annual conference on Design automation, July 24-28, 2006, San Francisco, CA, USA [doi>10.1145/1146909.1147108]
• 18: P. Yu, S. X. Shi, and D. Z. Pan, "True Process Variation Aware Optical Proximity Correction with Variational Lithography Modeling and Model Calibration," Journal of Microlithography, Microfabrication and Microsystems, vol. 6, no. 3, Jul.--Sep. 2007.
• 19: N. Cobb, "Flexible sparse and dense OPC algorithms," in Proc. SPIE 5853, Jun. 2005, pp. 693--702.
• 20: N. B. Cobb and Y. Granik, "Dense OPC for 65nm and below," in Proc. SPIE 5992, Nov. 2005, pp. 1521--1532.
• 21: N. Cobb and D. Dudau, "Dense OPC and verification for 45nm," in Proc. SPIE 6154, Apr. 2006, pp. 191--196.
• 22: Y. Granik, D. M. Medvedev, and N. Cobb, "Toward standard process models for OPC," in Proc. SPIE 6520, Apr. 2007.
• 23: Steven W. Smith, The scientist and engineer's guide to digital signal processing, California Technical Publishing, San Diego, CA, 1997
• 24: Thomas H. Cormen , Clifford Stein , Ronald L. Rivest , Charles E. Leiserson, Introduction to Algorithms, McGraw-Hill Higher Education, 2001
• 25: Y. Granik, "Dry etch proximity modeling in mask fabrication," in Proc. SPIE 5130, Aug. 2003, pp. 86--91.
• 26: Louisa Lam , Seong-Whan Lee , Ching Y. Suen, Thinning Methodologies-A Comprehensive Survey, IEEE Transactions on Pattern Analysis and Machine Intelligence, v.14 n.9, p.869-885, September 1992 [doi>10.1109/34.161346]
• 27: Azriel Rosenfeld , John L. Pfaltz, Sequential Operations in Digital Picture Processing, Journal of the ACM (JACM), v.13 n.4, p.471-494, Oct. 1966 [doi>10.1145/321356.321357]
• 28: N. B. Cobb and Y. Granik, "Model-based OPC using the MEEF matrix," in Proc. SPIE 4889, Dec. 2002, pp. 1281--1292.