“Dry” Lithography Using Liquid and Supercritical Carbon Dioxide Based Chemistries and Processes

Novel carbon dioxide (CO/sub 2/) soluble photoresists were synthesized based on random copolymers of 1,1-dihydroperfluorooctylmethacrylate and 2-tetrahyrdopyranyl methacrylate. These resins, along with specially designed CO/sub 2/-soluble photoacid generators, were utilized to demonstrate the potential for a new "dry" lithographic process. Photoresist spin casting, development, and stripping were all carried out using only liquid and supercritical CO/sub 2/ as the processing medium. A novel high-pressure spin coating process was used to deposit the photoresist films. Parameters such as resist sensitivity, contrast, and resolution were investigated. Wafers were imaged using both 248and 193-nm radiation, demonstrating the potential of this new photoresist platform for use as a sustainable technology for the microelectronics industry.