E-Beam Application Of Highly Sensitive Positive And Negative-Tone Resists For X-Ray Mask Making

Resist sensitivity is one of the limiting factors in X-ray as well as e-beam lithography. To overcome the rather low sensitivities of commonly used resists like PMMA, a positive-tone X-ray resist ("RAY-PF") has been recently developed, which makes use of the concept of "chemical amplification". Since a novolak is included as a binder matrix, development can be performed by aqueous alkaline solutions, e.g. RAZ-Developer. Replacement of the dissolution inhibitor in RAY-PF by a chemical crosslinker yields a negative-tone resist ("RAY-PN") with very similar processing. The present investigation refers to the application of both resist types, originally designed to meet the demands of X-ray lithography, to high resolution e-beam lithography as applied for X-ray mask fabrication.