Mechanistic Study of Plasma Damage of Low k Dielectric Surfaces
- Materials Laboratory for Interconnect and Packaging, University of Texas at Austin, Austin, TX 78712-1063 (United States)
- Tokyo Electron U.S. Holdings Inc., 2400 Grove Blvd., Mail stop C310, Austin, TX 78741 (United States)
- Intel Corporation, Logic Technology Development, Hillsboro, OR 97124 (United States)
Plasma damage to low k dielectric materials was investigated from a mechanistic point of view. Low k dielectric films were treated by plasma Ar, O{sub 2}, N{sub 2}/H{sub 2}, N{sub 2} and H{sub 2} in a standard RIE chamber and the damage was characterized by Angle Resolved X-ray Photoelectron Spectroscopy (ARXPS), X-Ray Reflectivity (XRR), Fourier Transform Infrared Spectroscopy (FTIR) and Contact Angle measurements. Both carbon depletion and surface densification were observed on the top surface of damaged low k materials while the bulk remained largely unaffected. Plasma damage was found to be a complicated phenomenon involving both chemical and physical effects, depending on chemical reactivity and the energy and mass of the plasma species. A downstream hybrid plasma source with separate ions and atomic radicals was employed to study their respective roles in the plasma damage process. Ions were found to play a more important role in the plasma damage process. The dielectric constant of low k materials can increase up to 20% due to plasma damage and we attributed this to the removal of the methyl group making the low k surface hydrophilic. Annealing was generally effective in mitigating moisture uptake to restore the k value but the recovery was less complete for higher energy plasmas. Quantum chemistry calculation confirmed that physisorbed water in low k materials induces the largest increase of dipole moments in comparison with changes of surface bonding configurations, and is primarily responsible for the dielectric constant increase.
- OSTI ID:
- 21036011
- Journal Information:
- AIP Conference Proceedings, Vol. 945, Issue 1; Conference: 9. International workshop on stress-induced phenomena in metallization, Kyoto (Japan), 4-7 Apr 2007; Other Information: DOI: 10.1063/1.2815773; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANNEALING
COMPARATIVE EVALUATIONS
DIELECTRIC MATERIALS
DIPOLE MOMENTS
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
HYDROGEN
INFRARED SPECTRA
INTEGRATED CIRCUITS
IONS
MOISTURE
PERMITTIVITY
PLASMA
REFLECTIVITY
SURFACES
THIN FILMS
X RADIATION
X-RAY PHOTOELECTRON SPECTROSCOPY