Enhancement of isopropanol-based photoresist removal by the addition of aqueous alkaline solutions

Removal of photoresist films along with underlying hexamethyldisilazane (HM DS) layers from SiO2 surfaces was studied using isopropanol (IPA) and IPA/N H4OH/H2O mixtures. Although IPA removed photoresist layers, pure IPA was un able to remove the HMDS layer, even at temperatures above 60 degreesC and p ressures above 50 psi. Addition of NH4OH/H2O to IPA resulted in attack of t he Si-O-Si bonds at the Si/HMDS interface. Residual carbon concentrations a s low as 2.5 at. % on the posttreated surfaces were observed. IPA/NH4OH/H2O surfaces exhibited hydrophilic contact angles (15 degrees -20 degrees) ind icating removal of both photoresist and the adhesion promoter layer from si licon dioxide surfaces. Atomic force microscopy analyses indicated no incre ase in the SiO2 surface root-mean-square roughness. (C) 2001 American Vacuu m Society.