Hole Formation (Etching) in Polymers by Far (Deep) UV High Intensity Laser (Eximer) Radiation Pulses and Its Relevance to Photoresists in Deep UV Photolysis of Polymers

摘要

Pulsed eximer laser light (193nm) has been used to study the photo and thermal induced degradation (ablation) of six common, industrially important polymers. A spoon gauge was employed to determine the rate loss of gaseous products from a film. Optical microscopy allowed visualization of the changes that take place in the polymer near the site of hole formation. Little correlation was observed between the depth of holes generated and ave. pulse power or total energy applied. Temperature increases in the polymer film were monitored during irradiation. An attempt was made to correlate calculated and experimental ejection velocities of oligomer fragments of polymer formal by irradiation. The amount of such 'sputtered' material is small as opposed to gaseous products. Correlations were made between the percent transmission of infrared light through each type of polymer and the number of pulses. Keywords: Photoresists, Photolysis, Polymethylmethacrylate (Plexiglass), Polyimide (Kapton), Polycarbonate, Polystyrene, Polypropylene and Polyethyleneterephthalate, Polymeric films. (aw)