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Title: In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO{sub 2}

Abstract

We have employed attenuated total reflection Fourier transforms infrared spectroscopy (ATR-FTIRS) to monitor the profile evolution of patterned mesoporous, low-dielectric-constant SiO{sub 2} films in situ and in real time during plasma etching. A stack of patterned photoresist, anti-reflective coating, and mesoporous SiO{sub 2} is etched in an inductively coupled plasma reactor, using CHF{sub 3} and Ar. During etching, the IR absorbance of Si-O-Si stretching modes near 1080 cm{sup -1} decreases, and the rate of decrease in Si-O-Si absorbance translates to the SiO{sub 2} removal rate. When corrected for the exponentially decaying evanescent electric field, the removal rate helps monitor the profile evolution and predict the final etch profile. The predicted profiles are in excellent agreement with the cross-sectional images taken by scanning electron microscopy. In a similar approach, we calculate the absolute total number of C-F bonds in the sidewall passivation and observe its formation rate as a function of time. Assuming that the thickness of the sidewall passivation tapers down towards the trench bottom, we deduce that C-F formation occurs mostly in the final stage of etching when the trench bottom meets the Ge ATR crystal and that a critical amount of C-F buildup is necessary to maintain themore » anisotropic etch profile.« less

Authors:
; ; ;  [1]
  1. University of New Mexico, Albuquerque, New Mexico 87131 (United States)
Publication Date:
OSTI Identifier:
20637029
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films
Additional Journal Information:
Journal Volume: 23; Journal Issue: 2; Other Information: DOI: 10.1116/1.1865154; (c) 2005 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0734-2101
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ANISOTROPY; CHEMICAL BONDS; CRYSTALS; DIELECTRIC MATERIALS; ETCHING; FOURIER TRANSFORM SPECTROMETERS; GERMANIUM; INFRARED SPECTRA; PERMITTIVITY; PLASMA; SCANNING ELECTRON MICROSCOPY; SILICON OXIDES; THIN FILMS; TIME DEPENDENCE

Citation Formats

Gerung, Henry, Brinker, C Jeffrey, Brueck, Steven R.J., and Han, Sang M. In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO{sub 2}. United States: N. p., 2005. Web. doi:10.1116/1.1865154.
Gerung, Henry, Brinker, C Jeffrey, Brueck, Steven R.J., & Han, Sang M. In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO{sub 2}. United States. https://doi.org/10.1116/1.1865154
Gerung, Henry, Brinker, C Jeffrey, Brueck, Steven R.J., and Han, Sang M. 2005. "In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO{sub 2}". United States. https://doi.org/10.1116/1.1865154.
@article{osti_20637029,
title = {In situ real-time monitoring of profile evolution during plasma etching of mesoporous low-dielectric-constant SiO{sub 2}},
author = {Gerung, Henry and Brinker, C Jeffrey and Brueck, Steven R.J. and Han, Sang M},
abstractNote = {We have employed attenuated total reflection Fourier transforms infrared spectroscopy (ATR-FTIRS) to monitor the profile evolution of patterned mesoporous, low-dielectric-constant SiO{sub 2} films in situ and in real time during plasma etching. A stack of patterned photoresist, anti-reflective coating, and mesoporous SiO{sub 2} is etched in an inductively coupled plasma reactor, using CHF{sub 3} and Ar. During etching, the IR absorbance of Si-O-Si stretching modes near 1080 cm{sup -1} decreases, and the rate of decrease in Si-O-Si absorbance translates to the SiO{sub 2} removal rate. When corrected for the exponentially decaying evanescent electric field, the removal rate helps monitor the profile evolution and predict the final etch profile. The predicted profiles are in excellent agreement with the cross-sectional images taken by scanning electron microscopy. In a similar approach, we calculate the absolute total number of C-F bonds in the sidewall passivation and observe its formation rate as a function of time. Assuming that the thickness of the sidewall passivation tapers down towards the trench bottom, we deduce that C-F formation occurs mostly in the final stage of etching when the trench bottom meets the Ge ATR crystal and that a critical amount of C-F buildup is necessary to maintain the anisotropic etch profile.},
doi = {10.1116/1.1865154},
url = {https://www.osti.gov/biblio/20637029}, journal = {Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films},
issn = {0734-2101},
number = 2,
volume = 23,
place = {United States},
year = {Tue Mar 01 00:00:00 EST 2005},
month = {Tue Mar 01 00:00:00 EST 2005}
}