Polymer Chemistry Group

High Refractive Index Photoresists for 193 nm Immersion Lithography

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Immersion lithography is currently used to generate computer chips at the 45 nm device node. Modelling of the lithography process has shown that increasing the refractive index (RI) of photoresists at 193 nm cab improve the depth of focus (DOF) and exposure latitude (EL), which are two important parameters in a manufacturing environment. The refractive indices of most currently-used resists are around 1.7 at 193 nm. To achieve a significant improvement in DOF and EL this needs to be increased to 1.9 or higher.

Research at UQ has focussed on developing Quantitative structure properties relationships (QSPR) and using the information gained from the models to guide the synthesis of polymers with high refractive index values at 193 nm.

Figure 1 Comparison of experimental and calculated RI (determined by QSPR)

This program was supported by an ARC Linkage Projects grant (LP0667941), in collaboration with Sematech, a consortium of international semiconductor companies

Collaborators

Will Conley and Dr Paul Zimmerman (Sematech)

Point of contact: and

Publications

  1. Blakey, I.; Conley, W.; George, G. A.; Hill, D. J. T.; Liu, H.; Rasoul, F.; Whittaker, A. K. Synthesis of High Refractive Index Sulfur Containing Polymers for 193nm Immersion Lithography; a Progress Report. Proceedings of SPIE-The International Society for Optical Engineering 2006, 6153, 61530H/61531-61530H/61510.

  2. Blakey, I.; Chen, L.; Dargaville, B.; Liu, H.; Whittaker, A.; Conley, W.; Piscani, E.; Rich, G.; Williams, A.; Zimmerman, P. Novel High-Index Resists for 193-Nm Immersion Lithography and Beyond. Proc. SPIE-Int. Soc. Opt. Eng. 2007, 6519, 651909/651901-651909/651909.

  3. Whittaker, A. K.; Blakey, I.; Chen, L.; Dargaville, B.; Liu, H.; Conley, W.; Zimmerman, P. A. Rational Design of High-Ri Resists for 193-Nm Immersion Lithography. J. Photopolym. Sci. Technol. 2007, 20, 665-671.

  4. Zimmerman, P. A.; van Peski, C.; Rice, B.; Byers, J.; Turro, N. J.; Lei, X.; Gejo, J. L.; Liberman, V.; Palmacci, S.; Rothschild, M.; Whittaker, A.; Blakey, I.; Chen, L.; Dargaville, B.; Liu, H. Status of High-Index Materials for Generation-Three 193 Nm Immersion Lithography. J. Photopolym. Sci. Technol. 2007, 20, 643-650.

  5. Liu, H.; Blakey, I.; Conley, W. E.; George, G. A.; Hill, D. J. T.; Whittaker, A. K. Application of Quantitative Structure Property Relationship to the Design of High Refractive Index 193i Resist. Journal of Micro/Nanolithography, MEMS, and MOEMS 2008, 7, 023001/023001-023001/023011.

  6. Zimmerman, P. A.; Byers, J.; Piscani, E.; Rice, B.; Ober, C. K.; Giannelis, E. P.; Rodriguez, R.; Wang, D.; Whittaker, A.; Blakey, I.; Chen, L.; Dargaville, B.; Liu, H. Development of an Operational High Refractive Index Resist for 193nm Immersion Lithography. Proc. SPIE-Int. Soc. Opt. Eng. 2008, 6923, 692306.