The Effects of Secondary Electrons from a Silion Substrate on SR X-Ray Lithography

Abstract
The effects of secondary electrons from an Si substrate have been investigated quantitatively in SR lithography. It is confirmed that secondary electrons from an Si substrate produce undercuts of 0.1 µm in depth in the replicated resist patterns. The Si KLL Auger electron proves to be the main cause of this problem. This is ascertained through analysis of many kinds of secondary electrons. Moreover, eliminating the wavelength which excites the Si 1s electron from the exposing SR is one promising way to lessen this problem. The resolution of SR lithography is also confirmed to improve to less than 0.1 µm in the practical wavelength, if secondary electrons from the substrate are effectively minimized.

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