Yoshihiko Nagata

Development of the pellicle for KrF excimer laser photolithography

This paper describes development of the pellicle for KrF excimer laser photolithography. The components of KrF excimer pellicle should have high light resistance. Our pellicle membrane consists of amorphous perfluoropolymer. Since this material provides that scattering and absorption of light at deep-UV wavelength region are very small, transmissivity is high at that wavelength and light resistance is strong against KrF excimer laser. Membrane bond and reticle adhesive consist of silicone resin so that the light resistance of them is high. And the bond strength of our pellicle is very high despite the use of fluoro-polymer membrane. This is because the bond consists of silicone resin which contains fluorocarbon-group. Strict particle suppression is required for the excimer pellicle. We have covered the frame with UV resistant fluoropolymer for the purpose to reduce the possibility of particle generation. This treatment has suppressed the particle generation during transportation. Membrane cutting has been achieved by melt-cutting method. The prominency of this method is melting the membrane with heat and cutting it with no contact with pellicle frame, so that the membrane edge becomes smooth and pellicle frame has not been damaged.