Photolithography masks, systems and methods and more particularly to photolithography masks systems and methods for making and using silicon dioxide mask substrates are disclosed. The mask generally includes a silicon-dioxide mask substrate having a front surface, a patterned layer disposed on the front surface, and a coating of a fluoride of an element of group IIA that covers the patterned layer. The coating reduces undesired crystal growth on the silicon dioxide mask substrate. Such masks can be incorporated into photolithography systems and used in photolithography methods wherein a layer of photoresist is formed on a substrate and to radiation that impinges on the mask. Such a mask can be fabricated, e.g., by forming a patterned layer on a front surface of a silicon dioxide mask substrate and covering the patterned layer with a coating of a fluoride of an element of group IIA.