SANS Characterization of Nanoporous Thin Films for the Next Generation of Integrated Circuits

Published

July 1, 2002

Author(s)

Barry J. Bauer, V. J. Lee, R C. Hedden, Christopher Soles, D W. Liu, Wen-Li Wu

Abstract

The next generation of integrated circuits will be made from dielectric films that have very low dielectric constants (low-k) made possible by forming very small (< 50 ) pores in the matrix material. The nanoporosity not only lowers the average dielectric constant but also changes the strength, permeability, and other crucial properties of the films. Therefore, it is necessary to characterize the nature of the porosity to guide the synthetic efforts and to correlate a variety of electrical and mechanical properties. The small sample volume of 1-mm-thick films and the desire to characterize the film structure on silicon wafers narrows the number of available measurement methods. Small-angle neutron scattering (SANS) has been carried out on samples surrounded by saturated toluene vapor. The SANS signal goes through a minimum at a toluene-h8 / toluene-d8 ratio, which is the match point at which time the neutron contrast of the wall material is matched by the toluene mixture. The wall density can be calculated from this composition directly, without assuming any particular morphology type. The match point mixture is then used to fill the pores at various partial pressures of toluene vapor and SANS of these samples provides an independent measure of pore size distribution

Citation

Electronic Publication

Volume

35(13)

Pub Weblink

http://www.sns.gov/acns/

Pub Type

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Keywords

contrast match, low-k, neutron scattering, pores, SANS, thin film

Citation

Bauer, B. , Lee, V. , Hedden, R. , Soles, C. , Liu, D. and Wu, W. (2002), SANS Characterization of Nanoporous Thin Films for the Next Generation of Integrated Circuits, Electronic Publication, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852061, http://www.sns.gov/acns/ (Accessed October 30, 2025)