METHOD FOR CLEANING A PHOTO MASK

摘要

A method for cleaning a photo mask is provided to reduce variation of a phase and a transmittance ratio of the photo mask by preventing a Cr layer and an MoSiON layer from being etched during a cleaning process. A first cleaning process is performed on a photo mask to remove a polymer, which is formed on the photo mask in an oxide atmosphere(100). A second cleaning process is performed by using heated hydrogen peroxide and ozone water(102). A first heating process is performed on the photo mask(104). A third cleaning process is performed on the photo mask in a base atmosphere(106). A fourth cleaning process is performed on the photo mask by using the heated hydrogen peroxide and the ozone water(108). A second heat process is performed on the photo mask(110).