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Tzu-Chieh (Jake) Chou
Graduate Student, EAS

Commonly used in semiconductor device fabrication, plasma ashing removes the light-sensitive coating (photoresist) by reacting it with high-energy free radicals.

A rod-shaped piece of photoresist is ashed with oxygen plasma and leaves dark particle traces around it. The trace is the lightest on the left as the ashes are carried away and extracted by a vacuum pump on the right. Colorful thin-film interference patterns, on the other hand, mark possible redeposition of volatile compounds escaped from the photoresist.

The image size is 0.5 mm by 0.5 mm.


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