Advancing immersion lithography

This paper reports progress in developing and advancing Immersion Lithography beyond the current water based systems. Significant progress has been made in the development of 2(nd) generation immersion fluids. Many companies are developing fluids with refractive indices over 1.6. A significant number of these new fluids have been evaluated for application to optical lithography. The results are very promising. Imaging and linewidth control results for many fluids will be reported. It is shown that some of the new fluids are similar in impact on linewidth control performance to water. Some are not. Defect results from fluid droplet tests on resist and topcoats are also analyzed and reported. Results are compared with water. UV irradiation results for the fluids are also detailed. Indications are given that even though the fluid transmission properties of the fluids are degraded, recycling and rejuvenation of the fluid may be viable on the exposure tool.