Iodinated alternating copolymer as a chemically amplified resist for extreme UV lithography

초록

We proposed an iodinated alternating copolymer resist for extreme UV lithography to mitigate stochastic effects in resist materials by ensuring chemical uniformity for high-resolution patterning. As a first approach, an iodinated maleimide (IPMi) and tert-butoxystyrene (tBSt) were copolymerized via reversible-deactivation radical polymerization to yield IAC-1 with a narrow molecular weight distribution. However, the intrinsic hydrophobicity of iodinated moieties hindered positive-tone development in the tetramethylammonium hydroxide standard developer. To address this challenge, a composition-modulated alternating copolymer was designed to maintain structural consistency while providing controlled solubility. By incorporating and adjusting the content of a third hydrophilic monomer, hydroxylated maleimide (HPMi), the optimized polymer IAC-3 was synthesized. This material achieved positive-tone patterning down to 85nm under e-beam lithography and demonstrated solubility modulation under EUV exposure at 15 mJ/cm2. These findings highlight the potential of iodinated alternating copolymers with tailored compositions as a promising EUV resist platform. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

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