AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoM

Paper PS1-MoM5
The Effects of Pore Morphology on the Diffusive Properties of a Porous Low-K Dielectric

Monday, November 15, 2004, 9:40 am, Room 213A

Session: Low-k Dielectric Etching
Presenter: E.A. Joseph, University of Texas at Dallas
Authors: E.A. Joseph, University of Texas at Dallas
M.J. Goeckner, University of Texas at Dallas
L.J. Overzet, University of Texas at Dallas
D.W. Gidley, University of Michigan
B.E.E. Kastenmeier, IBM/International Sematech
Correspondent: Click to Email
Porous methylsilsesquioxane-based spin-on films with pore sizes of 1.5 - 2 nm and porosities ranging from 0 - 31% have been exposed to fluorocarbon and oxygen plasma chemistries to determine the integratability of the films. Using both spectroscopic ellipsometry and Auger electron spectroscopy, the porosity of the modified films was found to decrease during fluorocarbon and oxygen plasma exposure due to fluorine in-diffusion and carbon depletion, respectively. The depth of these compositional modifications is also measured and correlated to the porosity and pore interconnectivity, determined from Positronium Annihilation Lifetime Spectroscopy. Parallel studies of TaN atomic layer deposition also reveal tantalum in-diffusion, with diffusion lengths ranging from 40 - 125 nm (depending on porosity), and are comparable to those of fluorine, indicating that the diffusion and depletion lengths are governed by pore size and interconnectivity and are not material dependent. Lastly, moisture uptake in these films was examined and found to significantly affect both the overall porosity of the unprocessed films as well as the diffusion and depletion lengths of fluorine and carbon. @FootnoteText@ This work is supported by a grant from NSF/DOE, CTS-0078669.