"Dry" lithography using liquid and supercritical carbon dioxide based chemistries and processes

Novel carbon dioxide (CO₂) soluble photoresists were synthesized based on random copolymers of 1,1-dihydroperfluorooctylmethacrylate and 2-tetrahyrdopyranyl methacrylate. These resins, along with specially designed CO₂-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 CO₂ 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.