Title: High aspect ratio contact etching using C6F12O precursor with low global warming potential

Abstract

In the semiconductor industry, the size of nano-electronic devices is getting smaller and more integrated to form complex nanostructures on wafers. In order to manufacture a nano-electronic device, an accurate pattern must first be formed on a silicon substrate. Dry etching technology is mainly used in patterning processes to control the flux of active neutral species and charged particles formed in plasma and to form accurate nano-meter patterns. So far, due to the high chemical reactivity of silicon and fluorine, perfluorocarbon (PFC)-based gas chemistry including CF4, CHF3 and C4F8 has been used for nanopatterning of dielectric contacts. However, PFC gases generally have a high global warming potential (GWP) of over 8,000 and have a significantly negative impact on the ozone layer. Attempts have been made to replace, decompose, and/or recycle PFC gases with high GWP to reduce greenhouse effects in nano-sized electronic devices. For this, it is necessary to use low GWP gas for manufacturing nano-sized electronic devices in industrial fields. Low-GWP precursors exist as liquid sources with low boiling points or at room temperature for easy recovery. Therefore, to overcome the environmental issues in the manufacturing process for nano-sized semiconductor devices, the process applicability of liquid-PFC (L-PFC) gases (i.e., C6F12O, C7F14) should be further studied for fabricating nano-sized devices in advance. In this study, the etching process was performed using C6F12O, one of the precursors with low GWP. In addition, compared the HARC etching characteristics, plasma analysis and surface chemical bonding analysis of the conventional ICP system (13.56 MHz bias generator) and the ICP system with low RF frequency (2MHz) bias generator.