AVS 52nd International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS-ThM

Paper PS-ThM1
Plasma-Based Techniques to Reduce/Remove Particle Contamination for Pelicleless EUV and Imprint Lithography

Thursday, November 3, 2005, 8:20 am, Room 304

Session: Plasma-Surface Interactions II
Presenter: D.N. Ruzic, University of Illinois at Urbana-Champaign
Authors: D.N. Ruzic, University of Illinois at Urbana-Champaign
D.A. Alman, University of Illinois at Urbana-Champaign
B.E. Jurczyk, University of Illinois at Urbana-Champaign
H. Qiu, University of Illinois at Urbana-Champaign
M.J. Neumann, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
Particle contamination on EUV surfaces during mask blank deposition, mask fabrication, patterned mask handling can create significant distortions and loss of reflectivity and must be avoided. Particles on the order of 10nm are problematic during MLM mirror fabrication, since the introduced defects disrupt the local Bragg planes. The most serious problem is the accumulation of particles on surfaces of patterned blanks during EUV light exposure, since >25nm particles will be printed without an out-of-focus pellicle. Particle contaminants are also a problem with direct imprint processes since defects are printed every time. Several plasma-based techniques are under investigation aiming to reduce particle contamination through the use of controlled electrostatic repulsion and expulsion of particles from surfaces. The preliminary experiment simulates the particle contamination of mirror samples by introducing external insulating nano-particles of <200 nm size (PSL). Local charging of the particles is governed by the application of a plasma, electron beam, and voltage bias on the substrate. Coulomb explosions and Malter effects surface damage is minimized or eliminated by precise control of the local environment. Data from several plasma schemes to remove particles will be presented, including the first experiment demonstrating the removal of >85% of particles. Particles are imaged with a high-resolution SEM and numerically counted using contrast information from the image histogram. The capabilities for extending this process to higher levels suitable for manufacturing will be discussed.