Report on the Detailed Imaging Characterization Data for All Patterned Resists Including Resolution, Line-edge Roughness and Aspect-ratio Capabilities for Multiple Development Conditions
Research Report Highlight
Report outlines key lithographic results obtained during the evaluation of polyoxometalate cluster-based resists for potential application in EUV lithography. Results using i-line and electron-beam exposures are presented.
This report outlines key lithographic results obtained during the evaluation of polyoxometalate cluster based resists for potential application in EUV lithography. The contrast curve data complied here is a result of proxy i-line UV mask aligner exposures, with comparative electron-beam exposures. Specifically, octamolybdate clusters were combined with a tetrameric epoxide in varying ratios, with chemically amplified patterning action driven by the incorporation of ionic sulfonium or non-ionic naphthalimide photoacid generators. For i-line exposures peak contrast was 1.66, while the highest sensitivity was 1250 mJ/cm2, and increasing the content of octamolybdate clusters was seen to enhance contrast and reduce line edge roughness. Unfortunately, SEM evaluation of i-line UV exposures showed significant surface roughness. Electron-beam exposures at 2500 µC/cm2 incorporating the non-ionic photo-acid generator at 50 wt.% octamolybdate gave the lowest surface roughness and line-edge roughness of all examined systems, potentially due to the suppression of secondary electron or photoacid diffusion by the higher octamolybdate content. Octamolybdate clusters are strong candidates for further exploration, potentially even to suppress acid diffusion in positive tone systems.