Various sources contribute to mask haze formation including: chemical residuals from mask cleaning, out-gassing from pellicle glue/materials, and contaminants from the scanner ambient. This joint work examines cleaning techniques for haze minimization and whether or not there is haze formation after continuous laser irradiation. Masks with various designs and different cleaning techniques were tested in an ideal environment, isolated from out-gassing or other possible contaminants from the fab environment. Masks with and without patterns were subjected to 40kJ, accumulated dose, of laser radiation to simulate a wafer fab environment. Ion Chromatography (IC) and other surface analytical techniques were used to check the surface condition of masks before and after laser exposure. No haze was found on masks through transmission and IC measurements, when the test chamber was N 2 purged. This may suggest that new cleaning techniques have helped reduce chemical residuals on masks. It is less likely for haze to grow when masks are clean to an ionic level and when laser exposure occurs in an uncontaminated, purged environment.