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Title: Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition

Abstract

The preparation of ultralow dielectric constant porous silicon, carbon, oxygen, hydrogen alloy dielectrics, called 'pSiCOH', using a production 200 mm plasma enhanced chemical vapor deposition tool and a thermal treatment is reported here. The effect of deposition temperature on the pSiCOH film is examined using Fourier transform infrared (FTIR) spectroscopy, dielectric constant (k), and film shrinkage measurements. For all deposition temperatures, carbon in the final porous film is shown to be predominantly Si-CH{sub 3} species, and lower k is shown to correlate with increased concentration of Si-CH{sub 3}. NMR and FTIR spectroscopies clearly detect the loss of a removable, unstable, hydrocarbon (CH{sub x}) phase during the thermal treatment. Also detected are increased cross-linking of the Si-O skeleton, and concentration changes for three distinct structures of carbon. In the as deposited films, deposition temperature also affects the hydrocarbon (CH{sub x}) content and the presence of C=O and C=C functional groups.

Authors:
; ; ; ; ;  [1];  [2];  [2]
  1. IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20982845
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 9; Other Information: DOI: 10.1063/1.2718278; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON COMPOUNDS; CHEMICAL VAPOR DEPOSITION; CROSS-LINKING; DIELECTRIC MATERIALS; FOURIER TRANSFORMATION; HEAT TREATMENTS; HYDROCARBONS; HYDROGEN COMPOUNDS; INFRARED SPECTRA; NUCLEAR MAGNETIC RESONANCE; OXYGEN COMPOUNDS; PERMITTIVITY; POROUS MATERIALS; SHRINKAGE; SILICON COMPOUNDS; SPECTROSCOPY; THIN FILMS

Citation Formats

Gates, S. M., Neumayer, D. A., Sherwood, M. H., Grill, A., Wang, X., Sankarapandian, M., IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, and IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598. Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition. United States: N. p., 2007. Web. doi:10.1063/1.2718278.
Gates, S. M., Neumayer, D. A., Sherwood, M. H., Grill, A., Wang, X., Sankarapandian, M., IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, & IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598. Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition. United States. doi:10.1063/1.2718278.
Gates, S. M., Neumayer, D. A., Sherwood, M. H., Grill, A., Wang, X., Sankarapandian, M., IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, and IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598. Tue . "Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition". United States. doi:10.1063/1.2718278.
@article{osti_20982845,
title = {Preparation and structure of porous dielectrics by plasma enhanced chemical vapor deposition},
author = {Gates, S. M. and Neumayer, D. A. and Sherwood, M. H. and Grill, A. and Wang, X. and Sankarapandian, M. and IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099 and IBM T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598},
abstractNote = {The preparation of ultralow dielectric constant porous silicon, carbon, oxygen, hydrogen alloy dielectrics, called 'pSiCOH', using a production 200 mm plasma enhanced chemical vapor deposition tool and a thermal treatment is reported here. The effect of deposition temperature on the pSiCOH film is examined using Fourier transform infrared (FTIR) spectroscopy, dielectric constant (k), and film shrinkage measurements. For all deposition temperatures, carbon in the final porous film is shown to be predominantly Si-CH{sub 3} species, and lower k is shown to correlate with increased concentration of Si-CH{sub 3}. NMR and FTIR spectroscopies clearly detect the loss of a removable, unstable, hydrocarbon (CH{sub x}) phase during the thermal treatment. Also detected are increased cross-linking of the Si-O skeleton, and concentration changes for three distinct structures of carbon. In the as deposited films, deposition temperature also affects the hydrocarbon (CH{sub x}) content and the presence of C=O and C=C functional groups.},
doi = {10.1063/1.2718278},
journal = {Journal of Applied Physics},
number = 9,
volume = 101,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • Thin films of silicon boron nitride (SiBN) of typical composition Si{sub 0.09}B{sub 0.39}N{sub 0.51} and silicon boron oxynitride (SiBON) of typical composition Si{sub 0.16}B{sub 0.29}O{sub 0.41}N{sub 0.14} were prepared by plasma enhanced chemical vapor deposition and the properties of these films were evaluated with respect to their suitability as interconnection dielectrics in microelectronic fabrication. Films were deposited on 125 mm silicon substrates in a parallel-plate reactor at a substrate temperature of 400 C and a plasma power of 0.5 W/cm{sup 2}. Boron nitride, for comparison of electrical properties, was deposited from borazine (B{sub 3}N{sub 3}H{sub 6}); silicon boron nitride wasmore » deposited from borazine, disilane (Si{sub 2}H{sub 6}), and ammonia (NH{sub 3}); silicon boron oxynitride was deposited from borazine, disilane, ammonia, and nitrous oxide (N{sub 2}O). Metal-insulator-metal capacitors were fabricated and electrical measurements indicated that all three films had excellent dielectric properties with dielectric constants of 4.1, 4.7, and 3.9 for BN, SiBN, and SiBON, respectively. Tests of conformality indicated that deposition into trenches with an aspect ratio of 4:1 gave conformality greater than 70%. Silicon boron oxynitride was shown to be an excellent barrier to the diffusion of copper. A planar, single level metal-insulator structure was constructed using a SiBN/SiBON insulator with copper metallization.« less
  • Carbon-doped oxide materials (SiCOH films) with ultralow dielectric constants have been prepared by plasma-enhanced chemical vapor deposition (PECVD) from mixtures of SiCOH precursors with organic materials. The films have been characterized by Rutherford backscattering and forward recoil elastic scattering analysis, Fourier transform infrared spectroscopy and index of refraction measurements, and measurement of step heights in the films. The electrical properties of the films have been measured on metal--insulator--silicon structures. By proper choice of the precursor and deposition conditions, the dielectric constants of the SiCOH films can be reduced to values below 2.1, demonstrating the extendibility of PECVD-prepared carbon-doped oxides asmore » the interconnect dielectrics for future generation of very large scale integrated chips. {copyright} 2001 American Institute of Physics.« less
  • Polycrystalline boron nitride films have been deposited using microwave plasma-enhanced chemical vapor deposition. IR absorption spectra of films deposited using NaBH{sub 4} as the boron source in NH{sub 3} and H{sub 2} gases showed absorptions which are nearly the same as the characteristic vibrational modes seen in cubic and pyrolytic boron nitrides. Films deposited at 5 Torr also showed electron diffraction patterns for pyrolytic boron nitride, turbostratic boron nitride and cubic boron nitride. At higher gas pressures, only rings consistent with the formation of amorphous and cubic boron nitride were observed. Although the Raman spectra from a film deposited atmore » 60 Torr showed broad peaks at {similar to}1080 and {similar to}1310 cm{sup {minus}1}, the positions of the Raman lines for cubic boron nitride, no x-ray diffraction lines could be observed except that of the silicon substrate.« less
  • Cubic boron nitride ({ital c}-BN) film was deposited on Si(100) substrate using the chemical vapor deposition process assisted by high density plasma of Helicon wave with Borazine (B{sub 3}N{sub 3}H{sub 6}) precursor. It was found that the bombardment of ions with high flux and energy onto the film was necessarily required for synthesizing a {ital c}-BN film. Increasing a negative rf bias on the substrate increased the formation fraction of {ital c}-BN in the film. A nearly pure {ital c}-BN phase was synthesized at the conditions of plasma density in the reactor and rf substrate bias, above 10{sup 11} cm{supmore » {minus}3} and {minus}350 V, respectively. The phase identification of BN film was carried out by the transmission electron microscopy as well as Fourier transformed infrared spectroscopy. The infrared spectra for {ital c}-BN film synthesized at the rf bias of {minus}350 V appeared at 1093 cm{sup {minus}1} with a strong single peak, which is close to a value for the characteristic vibration mode of bulk {ital c}-BN (1065 cm{sup {minus}1}). The {ital c}-BN in the film was also confirmed and found to be a fine poly-crystalline with the grain sizes ranging from 200 to 400 A. {copyright} {ital 1996 American Institute of Physics.}« less
  • Preliminary experiments have been performed to probe the feasibility of using plasma enhanced chemical vapor deposition (PE--CVD) to prepare electrochromic thin films of tungsten oxide and molybdenum oxide by plasma reaction of WF/sub 6/, W(CO)/sub 6/, and Mo(CO)/sub 6/ with oxygen. Thin films produced in a 300 W, electrodeless, radio-frequency (rf), capacitive discharge were found to be electrochromic when tested with either liquid or solid electrolytes. Optical spectroscopy was performed on two electrochromic coatings after Li/sup +/ ion insertion from a propylene carbonate liquid electrolyte. Broad absorption peaks at --900 nm for WO/sub 3/ and 600 nm for MoO/sub 3/more » were observed. Optical results for PE--CVD MoO/sub 3/ films differ from those reported for evaporated MoO/sub 3/ films which have an absorption peak at --800 nm. The shorter wavelength absorption in the PE--CVD MoO/sub 3/ films offers the potential for fabricating electrochromic devices with higher contrast ratios and less color change. Optical emission spectroscopy, Auger, and x-ray diffraction analyses indicate these thin film deposits to be predominantly amorphous tungsten and molybdenum oxides.« less