Influence of 157-nm specific cleaning procedures on the quality of FIB repair depositions on reticles

Abstract

An UV lamp cleaning system (172nm) and a 157nm laser have been used to irradiate Ga-based focused ion beam (FIB) repair depositions on 193nm and 157nm reticles. The thickness change of the depositions due to the irradiation has been measured using an atomic force microscope. For the 193nm reticle additional transmission measurements were realized. These depositions are found to be highly resistant to UV lamp cleaning treatments of up to 18h (2mW/cm 2 , 1% O 2 ). Extended tests were also done with 157nm irradiation (9kJ/cm 2 , 1-10ppm O 2 ). At the end of these tests a film loss of the depositions of 0.4nm /kJ/cm 2 and a transmission change of 10% could be determined.