Cleaning of CHF3 plasma-etched SiO2/SiN/Cu via structures using a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone vapors

Kazuyoshi Ueno, Vincent M. Donnelly, Yasuaki Tsuchiya

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Cleaning processes for CHF3 reactive ion etched Cu vias, consisting of exposure to a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone [H(hfac)] vapors have been investigated. After each step in the cleaning process, the dielectric surface and the Cu surface of via structures were analyzed by in situ by angle-resolved x-ray photoelectron spectroscopy. A hydrogen plasma was effective in removing carbon and fluorine deposits on all of the surfaces, and CuO and Cu2O on the Cu surface at the via bottom. It was not effective, however, in removing the Cu deposited on the dielectric surfaces. An oxygen plasma is effective in removing all the carbon and some fluorine deposits. Cu deposits on the dielectric surfaces were not removed, however, and the Cu surface was oxidized. Exposure to H(hfac) vapors reduced some of the Cu deposits on the dielectric, however Cu diffusion into SiO2 possibly occurred during this exposure at the elevated temperature of 200 °C. CuO and Cu2O were removed by the H(hfac) exposure above 150 °C. A three-step cleaning sequence was devised which consists of a brief oxygen-plasma exposure, a dilute-HF solution dip, followed by exposure to H(hfac) vapors. The cleaning sequence is effective in obtaining a clean dielectric surface and an oxide-free Cu surface at the via bottom that allows low contact resistances of 5.8-6.8×10-11 Ω cm2.

Original languageEnglish
Pages (from-to)2986-2995
Number of pages10
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume16
Issue number6
Publication statusPublished - 1998 Nov
Externally publishedYes

Fingerprint

oxygen plasma
hydrogen plasma
cleaning
Cleaning
Vapors
vapors
Plasmas
Hydrogen
Oxygen
Deposits
deposits
Fluorine
fluorine
Carbon
carbon
Contact resistance
Photoelectron spectroscopy
contact resistance
x ray spectroscopy
photoelectron spectroscopy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)
  • Surfaces and Interfaces

Cite this

@article{fd7a1a7d2a814559b09493c630ec8211,
title = "Cleaning of CHF3 plasma-etched SiO2/SiN/Cu via structures using a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone vapors",
abstract = "Cleaning processes for CHF3 reactive ion etched Cu vias, consisting of exposure to a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone [H(hfac)] vapors have been investigated. After each step in the cleaning process, the dielectric surface and the Cu surface of via structures were analyzed by in situ by angle-resolved x-ray photoelectron spectroscopy. A hydrogen plasma was effective in removing carbon and fluorine deposits on all of the surfaces, and CuO and Cu2O on the Cu surface at the via bottom. It was not effective, however, in removing the Cu deposited on the dielectric surfaces. An oxygen plasma is effective in removing all the carbon and some fluorine deposits. Cu deposits on the dielectric surfaces were not removed, however, and the Cu surface was oxidized. Exposure to H(hfac) vapors reduced some of the Cu deposits on the dielectric, however Cu diffusion into SiO2 possibly occurred during this exposure at the elevated temperature of 200 °C. CuO and Cu2O were removed by the H(hfac) exposure above 150 °C. A three-step cleaning sequence was devised which consists of a brief oxygen-plasma exposure, a dilute-HF solution dip, followed by exposure to H(hfac) vapors. The cleaning sequence is effective in obtaining a clean dielectric surface and an oxide-free Cu surface at the via bottom that allows low contact resistances of 5.8-6.8×10-11 Ω cm2.",
author = "Kazuyoshi Ueno and Donnelly, {Vincent M.} and Yasuaki Tsuchiya",
year = "1998",
month = "11",
language = "English",
volume = "16",
pages = "2986--2995",
journal = "Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena",
issn = "1071-1023",
publisher = "AVS Science and Technology Society",
number = "6",

}

TY - JOUR

T1 - Cleaning of CHF3 plasma-etched SiO2/SiN/Cu via structures using a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone vapors

AU - Ueno, Kazuyoshi

AU - Donnelly, Vincent M.

AU - Tsuchiya, Yasuaki

PY - 1998/11

Y1 - 1998/11

N2 - Cleaning processes for CHF3 reactive ion etched Cu vias, consisting of exposure to a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone [H(hfac)] vapors have been investigated. After each step in the cleaning process, the dielectric surface and the Cu surface of via structures were analyzed by in situ by angle-resolved x-ray photoelectron spectroscopy. A hydrogen plasma was effective in removing carbon and fluorine deposits on all of the surfaces, and CuO and Cu2O on the Cu surface at the via bottom. It was not effective, however, in removing the Cu deposited on the dielectric surfaces. An oxygen plasma is effective in removing all the carbon and some fluorine deposits. Cu deposits on the dielectric surfaces were not removed, however, and the Cu surface was oxidized. Exposure to H(hfac) vapors reduced some of the Cu deposits on the dielectric, however Cu diffusion into SiO2 possibly occurred during this exposure at the elevated temperature of 200 °C. CuO and Cu2O were removed by the H(hfac) exposure above 150 °C. A three-step cleaning sequence was devised which consists of a brief oxygen-plasma exposure, a dilute-HF solution dip, followed by exposure to H(hfac) vapors. The cleaning sequence is effective in obtaining a clean dielectric surface and an oxide-free Cu surface at the via bottom that allows low contact resistances of 5.8-6.8×10-11 Ω cm2.

AB - Cleaning processes for CHF3 reactive ion etched Cu vias, consisting of exposure to a hydrogen plasma, an oxygen plasma, and hexafluoroacetylacetone [H(hfac)] vapors have been investigated. After each step in the cleaning process, the dielectric surface and the Cu surface of via structures were analyzed by in situ by angle-resolved x-ray photoelectron spectroscopy. A hydrogen plasma was effective in removing carbon and fluorine deposits on all of the surfaces, and CuO and Cu2O on the Cu surface at the via bottom. It was not effective, however, in removing the Cu deposited on the dielectric surfaces. An oxygen plasma is effective in removing all the carbon and some fluorine deposits. Cu deposits on the dielectric surfaces were not removed, however, and the Cu surface was oxidized. Exposure to H(hfac) vapors reduced some of the Cu deposits on the dielectric, however Cu diffusion into SiO2 possibly occurred during this exposure at the elevated temperature of 200 °C. CuO and Cu2O were removed by the H(hfac) exposure above 150 °C. A three-step cleaning sequence was devised which consists of a brief oxygen-plasma exposure, a dilute-HF solution dip, followed by exposure to H(hfac) vapors. The cleaning sequence is effective in obtaining a clean dielectric surface and an oxide-free Cu surface at the via bottom that allows low contact resistances of 5.8-6.8×10-11 Ω cm2.

UR - http://www.scopus.com/inward/record.url?scp=0010685921&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0010685921&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0010685921

VL - 16

SP - 2986

EP - 2995

JO - Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena

JF - Journal of Vacuum Science & Technology B: Microelectronics Processing and Phenomena

SN - 1071-1023

IS - 6

ER -