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STED-Inspired Cationic Photoinhibition Lithography.

ABSTRACT: Direct laser writing by two-photon lithography has been enhanced substantially during the past two decades by techniques borrowed from stimulated emission depletion (STED) microscopy. However, STED-inspired lithography was so far limited to radical polymerizations, mostly to acrylates and methacrylates. Cationic polymers did not derive benefits from this technique. Specifically, epoxide polymerization, which plays a paramount role in semiconductor clean-room technology, has not yet been reported with a second, depleting laser focus in the outer rim of the point spread function. We now found that using a thioxanthone as a sensitizer and sulfonium or iodonium salts as photoinitiators enables at least partial optical on/off switching of two-photon polymerization and, in the case of the sulfonium salt, allows for writing epoxy lines with widths shrunk by approx. two-thirds compared to lines written with two-photon polymerization alone.

SUBMITTER: Islam S

PROVIDER: S-EPMC10518867 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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STED-Inspired Cationic Photoinhibition Lithography.

Islam Sourav S Sangermano Marco M Klar Thomas A TA

The journal of physical chemistry. C, Nanomaterials and interfaces 20230907 37

Direct laser writing by two-photon lithography has been enhanced substantially during the past two decades by techniques borrowed from stimulated emission depletion (STED) microscopy. However, STED-inspired lithography was so far limited to radical polymerizations, mostly to acrylates and methacrylates. Cationic polymers did not derive benefits from this technique. Specifically, epoxide polymerization, which plays a paramount role in semiconductor clean-room technology, has not yet been reported ...[more]

PMID: 37752901

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