Effect of process parameters of UV enhanced gas phase cleaning on the removal of PMMA (Polymethylmethacrylate) from a Si substrate

Abstract

Experimental study of UV-irradiated O2/H2 gas phase cleaning for PMMA (Polymethylmethacrylate) removal is carried out in a load-locked reactor equipped with a UV lamp and PBN heater. UV enhanced O2/H2 gas phase cleaning removes polymethylmethacrylate (PMMA) better at lower process pressure with higher content of H2. O2 gas compete for UV (184.9 nm) absorption with PMMA producing O3, O(1D) and lower dissociation of PMMA. In our experimental conditions, etching reaction of PMMA at the substrate temperature between 75℃ and 125℃ had activation energy of about 5.86 kcal/mol indicating etching was controlled by surface reaction. Above the 180℃, PMMA removal was governed by a supply of reaction gas rather than by substrate temperature.