Polymerization Photoinitiators with Near-Resonance Enhanced Two-Photon Absorption Cross-Section: Toward High-Resolution Photoresist with Improved Sensitivity

Caroline Arnoux (1) , Tatsuki Konishi (2, 3) , Emma van Elslande (1) , Eric-Aimé Poutougnigni (1) , Jean-Christophe Mulatier , Lhoussain Khrouz , Christophe Bucher , Elise Dumont , Kenji Kamada (2, 3) , Chantal Andraud (1) , Patrice Baldeck , Akos Banyasz , Cyrille Monnereau

1 LC - Laboratoire de Chimie - UMR5182
2 AIST - National Institute of Advanced Industrial Science and Technology
3 Kwansei Gakuin University

We take advantage of the near-resonant enhancement of the third-order nonlinear response to engineer a two-photon polymerization photoinitiator with optimized efficiency in regard with literature benchmarks. We study in detail its linear and resonant third-order nonlinear optical properties, with a particular focus on photoinduced radical generation. Careful choice of peripheral substituents enable its direct solubilization into a mixture of commercial multifunctional acrylic monomers, resulting in homogeneous photoresist with good optical transparency upon simple mixing. When submitted to sub-nanosecond pulsed laser irradiation at 532 nm, the resulting photoresist displays a polymerization threshold up to eight times lower than that obtained with classically used two-photon initiators, giving rise to sub-100 nm linewidth at 250 nm interline separation, and resulting in highly defined threedimensional (3D) structures.

Domaines: Chimie; Matériaux; Sciences de l'ingénieur [physics]

Caroline Arnoux, Tatsuki Konishi, Emma van Elslande, Eric-Aimé Poutougnigni, Jean-Christophe Mulatier, et al.. Polymerization Photoinitiators with Near-Resonance Enhanced Two-Photon Absorption Cross-Section: Toward High-Resolution Photoresist with Improved Sensitivity. Macromolecules, 2020, 53 (21), pp.9264-9278. ⟨10.1021/acs.macromol.0c01518⟩. ⟨hal-03033204⟩