Stochastic defect generation depending on tetraalkylhydroxide aqueous developers in extreme ultraviolet lithography


 Patterning targets in leading-edge technologies such as extreme ultraviolet lithography (EUVL) are starting to push present photoresist materials (e.g., chemical amplification resists) to their physical limits. The appearance of randomly occurring (stochastic) photoresist-based defects in these stringent patterning targets has become one of the main concerns in EUVL. To obtain possible clues to understanding these stochastic defects, the effect of developer solutions (alkyl chain length of tetraalkylammonium hydroxide) on stochastic defects was investigated. This paper was built on our previous work in which we investigated the dissolution dynamics of three types of typical EUV photoresist processed in developer solutions with different alkyl chain lengths. Using the same materials, we found from EUV patterning experiments focusing on contact hole (CH) patterns that the long-alkyl-chain developer solution, i.e., tetrabutylammonium hydroxide, was effective in mitigating stochastic defects in acryl-type and hybrid-type photoresists (the latter being more commonly utilized for EUVL).