Effectiveness of high energy ion beam techniques for the characterization of mesoporous low dielectric-constant materials

Highly porous silica films can potentially reduce power dissipation, cross talk, and interconnection delay in the deep submicron regime of semiconduct or devices. We have synthesized "mesoporous" silica films using both cation ic and non-ionic surfactants to template porosity in spin-on sol-gel silica . During this development we have effectively used high-energy ion beam tec hniques along with optical profilometry to characterize the porosity of the se films. Rutherford backscattering spectrometry (RBS), and O-16(d, p(1))O- 17 nuclear reaction were used to determine the total number of Si and O ato ms in the films. Interaction of these films with water was characterized by the H-1(F-19, alpha gamma)O-16 resonant nuclear reaction. Combination of t hese techniques provides fast, accurate, and quantitative methods for chara cterizing these films. However, the high-energy ion beams appear to cause s ignificant damage in the films. X-ray photoelectron spectroscopy (XPS) meas urements from the ion beam interacted region show a tail in the low binding energy side of the Si 2p core level spectrum which is characteristic to me tal Si. In addition, craters as deep as 175 nn were left in the films where the ion beams interacted with the material. (C) 2000 Published by Elsevier Science B.V. All rights reserved.