AVS 53rd International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS1-WeM

Paper PS1-WeM9
Molecular Dynamics Simulations of Interactions of Ions and Radicals with Organic Masking Materials

Wednesday, November 15, 2006, 10:40 am, Room 2009

Session: Plasma-Surface Interactions II
Presenter: J.J. Végh, University of California at Berkeley
Authors: J.J. Végh, University of California at Berkeley
D.G. Nest, University of California at Berkeley
M. Goldman, University of California at Berkeley
D.B. Graves, University of California at Berkeley
R.L. Bruce, University of Maryland, College Park
S. Engelmann, University of Maryland, College Park
T. Kwon, University of Maryland, College Park
R. Phaneuf, University of Maryland, College Park
G.S. Oehrlein, University of Maryland, College Park
B. Long, University of Texas, Austin
G. Willson, University of Texas, Austin
A. Alizadeh, GE Electric Global Research Center
Correspondent: Click to Email
Plasma-organic polymer surface interactions are important in etching, deposition, surface treatment and modification. Organic polymers are used as etch masks in both conventional photoresists and in novel masking schemes such as imprint lithography and self-assembled block copolymer masks, but the mechanisms of etching are poorly understood. We describe studies of ion and radical impacts on organic polymer surfaces using molecular dynamics (MD) simulations, focusing on etch mechanisms for model polymers such as polystyrene. Experiments have revealed that polymers, including commercial photoresists, initially experience a rapid, drastic reduction in sputtering yield before reaching a much lower steady state value. The MD simulations reproduce this drop in sputtering yield, and are also able to predict the ion fluence necessary to reach steady state. Simulations reveal that the near-surface region becomes hydrogen-depleted with Ar@super +@ bombardment, leading to an amorphous carbon layer that reduces the sputtering yield by as much as two orders of magnitude. We present further results explaining polymer etch in the presence of F and CF with Ar@super +@ bombardment, contrasting polymer etch mechanisms with those of materials such as silicon. Results are compared with energetic beam and plasma experimental measurements.