In-line control and rapid process development of nitrided gate oxides

Duncan Rogers*, Tapani Laaksonen, Ajith Varghese, Christian Otten, Mike Kasner, Husam Alshareef, Richard Kuan, Malcolm Bevan

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Nitrided gate oxides on Si wafers were investigated by X-ray Photoelectron Spectroscopy (XPS) and non-contact surface voltage and surface photovoltage measurements of Corona-Oxide-Semiconductor (COS) structures. The XPS measured the physical parameters of N dose and film thickness, while the COS measured the equivalent oxide thickness and a leakage indicator. The XPS N dose, XPS thickness and the COS leakage indicator met the stability, precision, and time dependence requirements for process control, but the COS EOT was unstable possibly due to variations in substrate doping. In lot-based measurements of 65 nm node wafers, the COS leakage indicator correlated to gate leakage for two different oxide thicknesses with a correlation R 2 of 0.85, whereas XPS N dose correlated for only one oxide thickness with a correlation R 2 of 0.47. None of the lot-based measurements correlated to threshold voltage. The suitability of XPS, COS and single wavelength ellipsometry for rapid process development was determined by measuring pilot wafers processed alongside 65 nm node development lots. The measurements could predict threshold voltage only under variations of a limited set of process parameters. Under variations of several process parameters, only the COS leakage indicator could predict gate leakage.

Original languageEnglish (US)
Title of host publicationCHARACTERIZATION AND METROLOGY FOR ULSI TECHNOLOGY 2005 - International Conference
Pages172-176
Number of pages5
Volume788
DOIs
StatePublished - Sep 9 2005
Externally publishedYes
Event2005 International Conference on Characterization and Metrology for ULSI Technology - Richardson, TX, United States
Duration: Mar 15 2005Mar 18 2005

Other

Other2005 International Conference on Characterization and Metrology for ULSI Technology
CountryUnited States
CityRichardson, TX
Period03/15/0503/18/05

Keywords

  • Corona-oxide- semiconductor
  • Ellipsometry
  • Nitrided gate oxid
  • Surface photovoltage
  • X-ray photoelectron spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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