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Proceedings Paper

Chemistry of photoresist recycling: II
Author(s): Hideki Nishida; Masamichi Moriya; Itaru Shiiba; Katsuto Taniguchi
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Paper Abstract

We have been researching chemical changes that occur in positive-type photoresist within a recycling process. In this process, spin-coated photoresist is first collected together with the thinner used for washing the coated cup, and the diluted resists is then distilled. Next, by adding an appropriate amount of solvent, the viscosity of the resist is returned to its initial state. The resist is finally filtered and returned for use. Simulation experiments were performed using a spin coated. It was found that the photoresist takes on about 1 percent water content by absorbing moisture from the atmosphere during the spin- coating process, and that diazonaphthoquinone decomposes due to thermal stress, which is connected with a drop in photo- sensitivity. Accordingly, if the photoresist should happen to be free of water, and if heat should not happen to cause chemical changes in diazonaphthoquinone during refinement, sensitivity should not show a change in the extracted photoresist. With this in mind, it was decided that extracted photoresist must be refined in low-moisture conditions at low temperature. This photoresist recycling is therefore performed by refining photoresist at room temperature using equipment that can distill under reduced pressure. By adding fresh photoresist, this type of recycling can be continuously performed.

Paper Details

Date Published: 11 June 1999
PDF: 7 pages
Proc. SPIE 3678, Advances in Resist Technology and Processing XVI, (11 June 1999); doi: 10.1117/12.350250
Show Author Affiliations
Hideki Nishida, Hitachi, Ltd. (Japan)
Masamichi Moriya, Hitachi, Ltd. (Japan)
Itaru Shiiba, Hitachi Device Engineering Co., Ltd. (Japan)
Katsuto Taniguchi, Clariant (Japan) K.K. (Japan)

Published in SPIE Proceedings Vol. 3678:
Advances in Resist Technology and Processing XVI
Will Conley, Editor(s)

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