Electron-Beam-Induced Freezing of an Aromatic-Based EUV Resist: A Robust Template for Directed Self-Assembly of Block Copolymers

Resist freezing is routinely used in lithography applications to facilitate double patterning and the directed self-assembly (DSA) of block copolymers. Previous reports of graphoepitaxy within patterned positive-tone resists used chemical freezing agents which are known to cause significant shrinkage of critical dimensions (CD). We report the “freezing” of an aromatic-based extreme ultraviolet resist by exposure to an electron beam, so did not require the use of chemical agents. Crucially, the process did not lead to significant changes in CD and line edge roughness, where the “frozen” patterns were resistant to treatment with solvents and annealing to temperatures well above the glass transition temperature of the uncrosslinked resist. Finally, we take advantage of these properties and demonstrate the utility of this process for applications in the DSA of block copolymers leading to pattern multiplication.