Excimer laser etching of polymers

Abstract

The ablative decomposition of polyimide, poly(methylmethacrylate), and TNS2 photoresist at high excimer laser (ArF and KrF) fluences (>1 J/cm2) is investigated. It is found that the mechanism of etching is both photochemical and thermal in nature at these fluences. A model, in which a thermal contribution to etching is added to the photochemical contribution derived from low fluence measurements, has been found to represent the experimental data satisfactorily. It is also shown that feature sizes as small as 0.4 μm can be delineated on polymeric materials in a self-developing manner using 193-nm laser pulses and contact-printing techniques.