High-performance topochemical polymerization-based photo-carving with sub-50 nm resolution utilizing visible light

Photosensitive topochemical polymerization, characterized by lattice-controlled reaction sites and rates, enables the production of highly crystalline and isotactic polymers, providing a powerful synthesis route for advancing high-performance lithographic technologies. However, the substantial challenge of achieving precise molecular packing and fabricating large-area single-crystal thin films required by topochemical reactions remains a major obstacle to realizing sub-diffraction, low-power lithographic technologies. In this study, we report a lattice-induced resolution enhancement method that exceeds the diffraction limit, in synergy with a dual solid-liquid interface confinement strategy, enabling efficient topochemical polymerization in both 2D and 3D lithographic applications. The directed fluid flow within the confined space effectively suppresses uncontrolled nucleation, facilitating the fabrication of large-area single-crystal thin-film photoresists with tunable thickness and aspect ratios. We demonstrate dual-mode photocarving on large-area photoresists at sub-50 nm resolution (λ/10) using a low-power continuous-wave visible laser (4-20 μW), which operates at power levels several orders of magnitude lower than those required for two-photon lithography. The entire process is compatible with standard commercial optical microscopes using standard optical components. Our research introduces a versatile platform for achieving subdiffractional lithographic resolution with low-power light, demonstrating a fivefold enhancement in resolution under identical illumination conditions compared to reported photoresists.