A novel platform of positive-tone organoantimony resists for EUV

The photo-chemical properties of metal-containing EUV resists are primarily determined by the ligands in the complex. Most metal-containing resists are negative-tone and their ligands help facilitate decreases in solubility upon exposure to EUV light. Positive-tone metal-containing resists are quite rare, despite numerous advantages to the use of positive-tone resists in the manufacture of integrated circuits. In this study, a series of complexes of the type R₃Sb(O₂CR’)₂ were designed to elucidate the structure-property relationship of the alkyl or aryl R groups and the carboxylate R' groups. The synthesis and evaluation of this series culminated in the discovery of six positive-tone organoantimony resists. One of the most surprising conclusions from this work is that the olefin-containing styrenecarboxylate ligand (-O₂CC₆H₄CH=CH₂) is principally responsible for the positive-tone imaging of all six of these resists.