Designing Photoresist Systems for Microlithography in Carbon Dioxide

摘要

Currently, the microlithography industry creates large amounts of organic and aqueous wastes in the production of semiconductors. Using carbon dioxide can possibly eliminate the majority of these waste solvents as well as eliminate the image collapse problems shown with aqueous base development. We will discuss the use of carbon dioxide to replace the most solvent intensive steps of the microlithography process, spin coating, developing, and stripping. However, before CO_2 can replace conventional solvents, photoresist systems must be designed and synthesized to be compatible with CO_2. These photoresist systems must be soluble in liquid CO_2 to insure that thin-uniform coatings can be produced by spin coating while maintaining characteristics of conventional resist systems such as low absorbance, high sensitivity, solubility contrast, good resolution, and etch resistance. Using our CO_2 compatible resist system, we will demonstrate the ability of CO_2 to spin coat uniform thin-films which (after exposing and PEB) can be developed using scCO_2 to produce lithography features that may be stripped in CO_2. Thus, revealing the enormous potential of CO_2 to provide the microlithography industry an opportunity to escape its water and organic solvent dependence as it moves toward 157nm lithography.