Plasma Dielectric Etching with C₄H₂F₆ Isomers of Low Global-Warming Potential

초록

This paper presents the observed changes when replacing the widely used CHF3 gas in semiconductor processing with two isomeric gases, C4H2F6-iso and C4H2F6-Z. This study investigates the etching process results of SiO2 and Si3N4 by varying the ratios of CHF3, C4H2F6 gases. The process outcomes were analyzed using ellipsometer and X-ray photoelectron spectroscopy, while plasma radical densities were examined through quadrupole mass spectrometry. The results are compared across five conditions, with substitution gas ratios ranging from 0% to 100%. The process results indicated that the selectivity increased at certain gas ratios. The diagnostic results provided the ratios of various etchants within the plasma. This research advances the development of alternative precursors designed to mitigate the effects of global warming.

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