Nitroxide‐mediated polymerization of adamantyl‐functional methacrylates for 193 nm photoresists

Abstract

Three different methacrylic monomers (γ‐butyrolactone methacrylate (GBLMA), 3‐hydroxyl‐1‐adamantyl methacrylate (HAMA), and 2‐methyl‐2‐adamantyl methacrylate (MAMA)), that are most often terpolymerized for 193 nm photoresists, were studied individually by nitroxide mediated polymerization (NMP) with succinimidyl ester terminated BlocBuilder (NHS‐BlocBuilder) using a small fraction ∼ 0.05 mol/mol (5 mol%) in the initial mixture of 2,3,4,5,6 pentafluorostyrene (PFS) controlling co‐monomer. The copolymerizations were done in 0.35 g/g (35 wt%) dioxane solution and were studied as functions of temperature (75 versus 90 °C) and added free SG1 nitroxide (none versus SG1:NHS‐BlocBuilder molar ratio ≈ 0.15) with the objective of minimizing the dispersity (trueM¯wtrue/trueM¯n). MAMA/PFS copolymerizations were not strongly influenced by temperature or addition of free nitroxide, with relatively linear number average molecular weight trueM¯n versus conversion plots and trueM¯wtrue/trueM¯n = 1.28–1.55. Further, MAMA/PFS polymerization kinetics was notably slower compared to GBLMA or HAMA copolymerizations with PFS. For GBLMA/PFS and HAMA/PFS copolymerizations, trueM¯wtrue/trueM¯n was reduced at the lower temperature of 75 °C but added SG1 did not play a strong role. For GBLMA/PFS, trueM¯wtrue/trueM¯n was reduced from 1.70–1.71 at 90 °C to 1.42–1.50 at 75 °C and for HAMA/PFS, trueM¯wtrue/trueM¯n was reduced from 1.36–1.47 at 90 °C to 1.22–1.31 at 75 °C.

Nitroxide-Mediated Polymerization: A Versatile Tool for the Engineering of Next Generation Materials

“…117 In 2017, Maric et al studied three different methacrylic monomers individually for use as 193 nm photoresists, γbutyrolactone methacrylate (GBLMA), 3-hydroxy-1-adamantyl methacrylate (HAMA), and 2-methyl-2-adamantyl methacrylate (MAMA), by performing NMP with PFS as a controlling monomer, finding that HAMA and MAMA polymerizations were easily controlled, where GBLMA presented more difficulties. 120 Methacrylates have a high equilibrium constant leading to irreversible termination, and therefore, the use of a small amount of controlling monomer, such as PFS or other styrenics, leads to a drop in the average equilibrium constant providing a controlled pseudoliving copolymerization. The information obtained in the previous study was used in the synthesis of GBLMA/HAMA/MAMA random copolymers with small molecular weight distributions via NMP to generate 193 nm argon flouride (ArF) photoresist materials that had relatively low absorbances and good optical transparency.…”

Nanotechnology of diamondoids for the fabrication of nanostructured systems

“…Recently, acrylate-based photoresists consisting of adamantane have been developed [103,[112][113][114][115][116]. Different adamantyl methacrylate materials have been produced and used as a photoresist composition for 193 nm argon fluoride (ArF) lithography [117][118][119][120]. These novel adamantane pendant group-containing photoresists are useful for improving the resolution limits of the feature sizes produced by ArF lithography due to the enhanced sensitivity to 193 nm light and in achieving better etching resistance for producing the finer features.…”

Experimental Methods in Chemical Engineering: Nuclear Magnetic Resonance

“…However, liquid‐state proton NMR successfully characterizes the cellulose nanocrystals’ precursors with carbazole and coumarin functionalities . A liquid‐state proton NMR, quantifies the degree of polymerization and the presence of different co‐polymers in PMMA resins . NMR detects chemical bonds and 1 H spectroscopy detects the hydrogen bond interactions between bisphenol F and an extracting agent in ionic liquids.…”