Rational Design of High-RI Resists for 193nm Immersion Lithography

We have developed a Quantitative Structure Property Relationship (QSPR) model for predicting the refractive index of small molecules and polymers at 193 nm. This model has been useful for screening databases of compounds for high refractive index to include in our program of synthesis of polymer having high RI. A range of novel target structures were identified and prepared via free radical polymerization. In addition polymers were also synthesized via Michael addition polymerization. Preliminary dose-to-clear and imaging experiments identified a number of promising candidates for incorporation into high refractive index resist materials. The platforms presented may be limited by relatively high intrinsic absorbance, and so design limits for incorporation of sulfur are given