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Title: Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry

Abstract

Plasma etching of HfO{sub 2} at an elevated temperature is investigated in chlorine-based plasmas. Thermodynamic studies are performed in order to determine the most appropriate plasma chemistry. The theoretical calculations show that chlorocarbon gas chemistries (such as CCl{sub 4} or Cl{sub 2}-CO) can result in the chemical etching of HfO{sub 2} in the 425-625 K temperature range by forming volatile effluents such as HfCl{sub 4} and CO{sub 2}. The etching of HfO{sub 2} is first studied on blanket wafers in a high density Cl{sub 2}-CO plasma under low ion energy bombardment conditions (no bias power). Etch rates are presented and discussed with respect to the plasma parameters. The evolution of the etch rate as function of temperature follows an Arrhenius law indicating that the etching comes from chemical reactions. The etch rate of HfO{sub 2} is about 110 A /min at a temperature of 525 K with a selectivity towards SiO{sub 2} of 15. x-ray photoelectron spectroscopy analyses (XPS) reveal that neither carbon nor chlorine is detected on the HfO{sub 2} surface, whereas a chlorine-rich carbon layer is formed on top of the SiO{sub 2} surface leading to the selectivity between HfO{sub 2} and SiO{sub 2}. A drift of themore » HfO{sub 2} etch process is observed according to the chamber walls conditioning due to chlorine-rich carbon coatings formed on the chamber walls in a Cl{sub 2}-CO plasma. To get a very reproducible HfO{sub 2} etch process, the best conditioning strategy consists in cleaning the chamber walls with an O{sub 2} plasma between each wafer. The etching of HfO{sub 2} is also performed on patterned wafers using a conventional polysilicon gate. The first result show a slight HfO{sub 2} foot at the bottom of the gate and the presence of hafnium oxide-based residues in the active areas.« less

Authors:
; ; ; ; ; ; ;  [1];  [2];  [3];  [4]
  1. STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France)
  2. (CEA-LETI), 38054 Grenoble Cedex 09 (France)
  3. (France)
  4. (United States)
Publication Date:
OSTI Identifier:
20776947
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 24; Journal Issue: 1; Other Information: DOI: 10.1116/1.2134707; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CARBON; CARBON DIOXIDE; CARBON TETRACHLORIDE; CHEMICAL REACTIONS; CHEMISTRY; CHLORINE; COATINGS; ETCHING; HAFNIUM CHLORIDES; HAFNIUM OXIDES; ION BEAMS; PLASMA; SILICA; SILICON OXIDES; SURFACES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Helot, M., Chevolleau, T., Vallier, L., Joubert, O., Blanquet, E., Pisch, A., Mangiagalli, P., Lill, T., Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des martyrs, LTPCM/INPG-CNRS-UJF, 1130 rue de la piscine, 38402 Saint-Martin-d'Heres, and Applied Materials, 974 E. Arques Ave. M/S 81334, Sunnyvale, California 94086. Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry. United States: N. p., 2006. Web. doi:10.1116/1.2134707.
Helot, M., Chevolleau, T., Vallier, L., Joubert, O., Blanquet, E., Pisch, A., Mangiagalli, P., Lill, T., Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des martyrs, LTPCM/INPG-CNRS-UJF, 1130 rue de la piscine, 38402 Saint-Martin-d'Heres, & Applied Materials, 974 E. Arques Ave. M/S 81334, Sunnyvale, California 94086. Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry. United States. doi:10.1116/1.2134707.
Helot, M., Chevolleau, T., Vallier, L., Joubert, O., Blanquet, E., Pisch, A., Mangiagalli, P., Lill, T., Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des martyrs, LTPCM/INPG-CNRS-UJF, 1130 rue de la piscine, 38402 Saint-Martin-d'Heres, and Applied Materials, 974 E. Arques Ave. M/S 81334, Sunnyvale, California 94086. Sun . "Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry". United States. doi:10.1116/1.2134707.
@article{osti_20776947,
title = {Plasma etching of HfO{sub 2} at elevated temperatures in chlorine-based chemistry},
author = {Helot, M. and Chevolleau, T. and Vallier, L. and Joubert, O. and Blanquet, E. and Pisch, A. and Mangiagalli, P. and Lill, T. and Laboratoire des Technologies de la Microelectronique, CNRS, 17 rue des martyrs and LTPCM/INPG-CNRS-UJF, 1130 rue de la piscine, 38402 Saint-Martin-d'Heres and Applied Materials, 974 E. Arques Ave. M/S 81334, Sunnyvale, California 94086},
abstractNote = {Plasma etching of HfO{sub 2} at an elevated temperature is investigated in chlorine-based plasmas. Thermodynamic studies are performed in order to determine the most appropriate plasma chemistry. The theoretical calculations show that chlorocarbon gas chemistries (such as CCl{sub 4} or Cl{sub 2}-CO) can result in the chemical etching of HfO{sub 2} in the 425-625 K temperature range by forming volatile effluents such as HfCl{sub 4} and CO{sub 2}. The etching of HfO{sub 2} is first studied on blanket wafers in a high density Cl{sub 2}-CO plasma under low ion energy bombardment conditions (no bias power). Etch rates are presented and discussed with respect to the plasma parameters. The evolution of the etch rate as function of temperature follows an Arrhenius law indicating that the etching comes from chemical reactions. The etch rate of HfO{sub 2} is about 110 A /min at a temperature of 525 K with a selectivity towards SiO{sub 2} of 15. x-ray photoelectron spectroscopy analyses (XPS) reveal that neither carbon nor chlorine is detected on the HfO{sub 2} surface, whereas a chlorine-rich carbon layer is formed on top of the SiO{sub 2} surface leading to the selectivity between HfO{sub 2} and SiO{sub 2}. A drift of the HfO{sub 2} etch process is observed according to the chamber walls conditioning due to chlorine-rich carbon coatings formed on the chamber walls in a Cl{sub 2}-CO plasma. To get a very reproducible HfO{sub 2} etch process, the best conditioning strategy consists in cleaning the chamber walls with an O{sub 2} plasma between each wafer. The etching of HfO{sub 2} is also performed on patterned wafers using a conventional polysilicon gate. The first result show a slight HfO{sub 2} foot at the bottom of the gate and the presence of hafnium oxide-based residues in the active areas.},
doi = {10.1116/1.2134707},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 1,
volume = 24,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}