AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoM

Paper PS-MoM7
Charge Density Measurements in a Metal Etch Strip/Passivation Chamber

Monday, October 25, 1999, 10:20 am, Room 609

Session: Plasma Damage
Presenter: R.L. Jarecki, Sandia National Laboratories
Authors: R.L. Jarecki, Sandia National Laboratories
M.G. Blain, Sandia National Laboratories
J.S. Papanu, Applied Materials, Inc.
Correspondent: Click to Email
Manufacturers have increasingly incorporated chambers capable of resist stripping as well as in situ passivation of etch residues on their metal etch tool platforms to mitigate corrosion resulting from exposure to atmospheric moisture. Such chambers typically feature a downstream microwave collisional plasma source with a pressure in the 0.5 to 10 Torr range using multiple-step chemistries based mainly on O@sub 2@ (for fast resist strip) and H@sub 2@O (for passivation by chlorine scavenging). Although "downstream" plasma strip processes are usually presumed to be almost charge-free due to the rapid decay of plasma density away from the source, it may be advantageous in practice to allow some level of charge to survive in order to increase the flux of etchant species to the wafer, and hence throughput. This study reports the direct measurement of ion current densities observed via Langmuir probe in a commercial in situ strip and passivation chamber, for various gas feeds and hardware configurations, to help assess the level of charging damage to actual devices. Wafer level ion current densities below 2x10@super -8@ A/cm@super 2@ for typical strip processes and 8x10@super -10@ A/cm@super 2@ for passivation processes were observed with a standard gas distribution baffle configuration, while modified baffle configurations resulted in somewhat higher ion currents. Increases in power or total flow rate tended to increase current density. Correlation of probe measurements to surface photovoltage and antenna structure data will also be discussed@footnote 1@. @FootnoteText@ @footnote 1@Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract No. DE-AC04-94AL85000.