What is it about?
Recently, a research team headed by Professor Cuifang Kuang from the Zhejiang Lab at Zhejiang University made a significant breakthrough by developing a new type of cationic epoxy photoresist.【双光子环氧光刻胶】 This innovative material exhibited around 600 times greater sensitivity to two-photon laser exposure than the traditional SU-8 photoresist, thanks to a unique bimolecular sensitization system. Professor Kuang explains, “We demonstrated the 3D fabricated structures with fine features of less than 200 nanometers (nm) and fast writing speed of 100 millimeters/second (mm/s) using nanolattices to show potential application for high-throughput nanofabrication of microscopic 3D devices”. Their findings were published in Advanced Functional Materials on September 6, 2024.
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Why is it important?
Two-photon laser direct writing lithography or TPL is a cutting-edge technique used for creating tiny nanoscale structures. It works by leveraging specific materials known as photoresists, which change their chemical properties when exposed to light. These materials absorb laser light in a unique way, enabling precise control during exposure to laser beams. Unlike conventional ultraviolet (UV) photolithography, which uses light to create images, TPL can directly build complex three-dimensional (3D) shapes that include features like overhangs and suspended elements at a resolution smaller than the width of a human hair. However, the production speed of TPL cannot match that of UV lithography. To speed up the TPL process, highly sensitive photoresists are essential. To date, the classic SU-8 epoxy photoresist series remains a popular choice because of its numerous benefits, such as a high depth-to-width ratio, minimal shrinkage, and no issues with oxygen interference during processing. However, cationic photoresists like SU-8 generally take longer to fabricate and result in less detailed structures compared to free-radical-based photoresists, which can limit their applications in creating intricate microdevices.
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This page is a summary of: Highly Sensitive Cationic Photoresist for High‐Throughput Two‐Photon Nanofabrication, Advanced Functional Materials, September 2024, Wiley,
DOI: 10.1002/adfm.202409859.
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