AVS 52nd International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoA

Paper PS1-MoA9
Effect of Species Density and Ion Scattering During Ashing on Ultra Low-@kappa@ Inter-Level Dielectric Films

Monday, October 31, 2005, 4:40 pm, Room 302

Session: Dielectric Etch I
Presenter: M.A. Worsley, Stanford University
Authors: M.A. Worsley, Stanford University
S.F. Bent, Stanford University
N.C.M. Fuller, IBM TJ Watson Research Center
J. Doyle, IBM TJ Watson Research Center
M. Rothwell, IBM TJ Watson Research Center
T.L. Tai, IBM Microelectronics Division
T.J. Dalton, IBM TJ Watson Research Center
Correspondent: Click to Email
The challenge of integrating ultra low-@kappa@ inter-level dielectric (ILD) materials in dual damascene integration schemes continues be a key issue in the microelectronics industry. For the 45 nm technology node and beyond, the ITRS roadmap predicts the need for porous organosilicate glass (OSG) materials. It has been shown that these porous OSG materials are even more susceptible to modification by photoresist ash plasmas than dense OSG films. Therefore, a more detailed understanding of the plasma characteristics that mitigate this modification is critical for successful integration of ultra low-@kappa@ ILDs in current integration schemes. Previous work by these authors has revealed several factors that influence modification using various techniques focused on analysis of the modified ILD. The present work combines that material analysis of the modified ILD with characterization of some key parameters in the plasma and at the plasma-surface interface. In this study, optical emission (OE) actinometry is used to measure the absolute densities of reactive radical species, and modeling of various plasma parameters (sheath thickness and positive ion mean free path) is used to estimate the significance of ion scattering in several ashing plasmas. Patterned structures in a porous OSG are ashed in conditions identical to that characterized and then analyzed using angle-resolved x-ray photoelectron spectroscopy (ARXPS). Data from the OE actinometry and modeling are combined with the ARXPS data to gain further insight into the mechanism by which modification of the OSG occurs in a patterned structure. Relevant results will be presented.