Silicon Oxide Etching Process of NF3 and F3NO Plasmas with a Residual Gas Analyzer.

Woo-Jae Kim,Hee-Tae Kwon,In-Young Bang,Jung-Hun Kwak,Gi-Won Shin,Gi-Chung Kwon,Ji-Hwan Kim,Min-Ho Kang,Yeon-Soo Park,Byung-Hyang Kwon,Youngjun Cho

doi:10.3390/ma14113026

Woo-Jae Kim, Hee-Tae Kwon + Show 9 more

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https://doi.org/10.3390/ma14113026

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Abstract

The use of NF3 is significantly increasing every year. However, NF3 is a greenhouse gas with a very high global warming potential. Therefore, the development of a material to replace NF3 is required. F3NO is considered a potential replacement to NF3. In this study, the characteristics and cleaning performance of the F3NO plasma to replace the greenhouse gas NF3 were examined. Etching of SiO2 thin films was performed, the DC offset of the plasma of both gases (i.e., NF3 and F3NO) was analyzed, and a residual gas analysis was performed. Based on the analysis results, the characteristics of the F3NO plasma were studied, and the SiO2 etch rates of the NF3 and F3NO plasmas were compared. The results show that the etch rates of the two gases have a difference of 95% on average, and therefore, the cleaning performance of the F3NO plasma was demonstrated, and the potential benefit of replacing NF3 with F3NO was confirmed.

Highlights

Since the 1980s, the use of NF3 plasmas in semiconductor, display, and solar cell processing applications has been investigated [1]
Cleaning the plasma-enhanced chemical vapor deposition (PECVD) chamber is performed by supplying ions and radicals for cleaning through a remote plasma source (RPS) [6] or by directly supplying ions and radicals through an in situ plasma discharge [7]
NF3 plasma is discharged only in a part of the chamber, and the plasma collapses in other parts; these parts may not be exposed to the plasma

Summary

Introduction

Since the 1980s, the use of NF3 plasmas in semiconductor, display, and solar cell processing applications has been investigated [1]. NF3 plasma is used to etch various thin films under reactive ion etching (RIE) conditions [2,3] or to clean a plasma-enhanced chemical vapor deposition (PECVD) chamber [4,5]. The share of NF3 in fluorinated gases increased from 13–28% in 2005 to 17–36% in 2010, and NF3 is currently the most widely used and released fluorinated gas [1,14]. It was included in the second commitment period of the Kyoto Protocol as the seventh greenhouse gas whose emissions are to be regulated [15]

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