Roll-to-roll UV imprint lithography for flexible electronics
article
We propose a roll-to-roll UV imprint lithography tool as a way to pattern flexible PET foil with µm-resolution. As a way to overcome dimensional instability of the foil and its effect on overlay, a self-align approach was investigated, that permits to make several layers in a single lithography step. Flexible Ni-stamps were used, with a single level and with 2 levels. The stamps were fabricated on wafers using conventional optical lithography and Si etching. Thin Ni replica, both single and multilevel, were obtained by electroplating using a thickness of 50 µm. The flexible Ni stamps were attached on the main drum that is placed on a conventional roll-to-roll machine. Resist was dispensed drop by drop by valve-jet nozzle using solvent-free UV resist. The imprint speed was of 0.35 m/min, using a UV illumination of 2 W. Fifty imprints were made in a row, equivalent to 20 m foil length. High imprint quality was observed with good reproducibility. All features type were replicated, from 500 µm contact pads to 800 nm wide trenches and 1 µm wide lines. A resolution of 800 nm in 1 µm thick resist was obtained for single level imprint. Multi-level imprints (2 levels) show the same quality in replication with a resolution of 1 µm.
TNO Identifier
431369
ISSN
01679317
Source
Microelectronic Engineering, 88(8), pp. 2052-2055.
Pages
2052-2055
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