Replication of 175‐Å lines and spaces in polymethylmethacrylate using x‐ray lithography

A new technique for fabricating high contrast x‐ray masks with simple patterns of lines and spaces less than 50 A in width is described. The successful replication of 175‐A lines and spaces in polymethylmethacrylate (PMMA) using the carbon K (45‐A) x‐ray is reported. It was found that PMMA structures smaller than 150 A in width lost their physical integrity and would not adhere to SiO2 substrates.