It is demonstrated that medium energy (10 keV) writing implantation of heavy ions into thin PMMA films produces photomasks which are locally opaque to UV and deep UV light. An excimer laser is an excellent illumination source for lithographic replication of these patterns because of its high UV light output and low spatial coherence. The writing beam implantation is performed on an electrostatic ion gun incorporating a liquid metal ion source (LMIS) of high brightness. Due to their similar spatial resolution limits, LMIS writing ion beam implantation and excimer laser illumination is an inherently compatible combination of mask production and mask replication techniques.