POS1-1431
Synthesis of Photoresist Polymers through a Multistep Flow Process Involving Copolymerization, End-Group Removal, and Deacetylation
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Gyeonghui Kim (Inha University)
Co-Author(s)
Abstract
As semiconductor feature sizes continue to shrink, chemically amplified photoresists (CARs) must maintain patterning performance while suppressing stochastic effects arising from the inhomogeneous distribution of resist components. This requires precise control over the molecular weight, molecular weight distribution, and composition of the copolymer resin. Achieving such uniformity requires structural control not only during polymerization but also throughout subsequent modification reactions, which often exhibit low efficiency and slow kinetics for complex copolymers. Flow reaction processes provide efficient heat transfer and precise reaction control, offering a route to improve the synthesis of photoresist polymers. Here, after batch optimization of the monomer feed composition, we applied flow processing to all three synthesis steps of poly(4-hydroxystyrene-r-2-methyl-2-adamantyl methacrylate) [poly(HST-r-MAdMA)], a model copolymer for CAR formulations. The synthesis consisted of reversible addition–fragmentation chain transfer (RAFT) copolymerization of 4-acetoxystyrene (ATST) and MAdMA, RAFT end group removal, and subsequent deacetylation. The flow-based process produced poly(ATST-r-MAdMA) with controlled molecular weight, dispersity, and composition, while requiring less than one-quarter of the corresponding batch reaction time for end group removal and approximately one-third for deacetylation. RAFT copolymerization and end group removal were also performed sequentially without precipitation while maintaining comparable structural control and end-group-removal efficiency. The resulting copolymers formed trench patterns with a critical dimension of approximately 70 nm by electron-beam lithography, with pattern quality comparable to that of copolymers synthesized in batch mode. These results demonstrate that flow processing can be applied across copolymerization and postpolymerization modifications for the efficient preparation of photoresist polymers.
