POS5-1363
Hydrophilicity-Modulated Iodine-Containing Alternating Copolymer Resists for Extreme Ultraviolet (EUV) Lithography
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
lee seoyeon (INHA University)
Co-Author(s)
Abstract
Extreme ultraviolet lithography (EUVL) is a critical patterning technology for advanced semiconductor fabrication, increasing the need for chemically amplified photoresists (CARs) that combine efficient photon utilization with reliable aqueous development. Incorporation of iodine into CAR polymers is a promising strategy for enhancing EUV absorption; however, the increased hydrophobicity associated with iodine can hinder dissolution in tetramethylammonium hydroxide (TMAH) developers. In this study, iodine-containing alternating copolymers with controlled chain composition were investigated as matrix resins for EUV photoresists. A binary alternating copolymer, P(IPMi-alt-tBSt), composed of N-(4-iodophenyl)maleimide (IPMi) and tert-butoxystyrene (tBSt), was synthesized by reversible addition–fragmentation chain-transfer polymerization. Although the polymer exhibited a low molecular weight and narrow molecular-weight distribution, its insufficient hydrophilicity led to poor dissolution contrast and unsuccessful pattern formation. To improve aqueous developability while retaining iodine-containing repeating units, N-(4-hydroxyphenyl)maleimide (HPMi) was incorporated as a hydrophilic comonomer, yielding composition-modulated quasi-alternating copolymers. Among the synthesized materials, P(IPMi/HPMi-alt-tBSt)-3 exhibited improved dissolution behavior and good patterning capability. The optimized resist produced 85 nm line features under - electron-beam exposure. Furthermore, its thin film exhibited an EUV-induced solubility switch at an exposure dose of 11 mJ/cm². These results suggest that hydrophilicity-modulated iodine-containing quasi-alternating copolymers are promising candidates for EUV photoresists.
