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Author Mingmei, Wang ♦ Kushner, Mark J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PLASMA PHYSICS AND FUSION TECHNOLOGY ♦ ACCELERATION ♦ DEPOSITION ♦ DIRECT CURRENT ♦ ELECTRIC POTENTIAL ♦ ELECTRODES ♦ ELECTRON BEAMS ♦ ELECTRONS ♦ ENERGY ABSORPTION ♦ EXCITATION ♦ IONIZATION ♦ IONS ♦ JOULE HEATING ♦ PLASMA ♦ PLASMA SHEATH ♦ STOCHASTIC PROCESSES ♦ ABSORPTION ♦ BEAMS ♦ CHARGED PARTICLES ♦ CURRENTS ♦ ELECTRIC CURRENTS ♦ ELECTRIC HEATING ♦ ELEMENTARY PARTICLES ♦ ENERGY-LEVEL TRANSITIONS ♦ FERMIONS ♦ HEATING ♦ LEPTON BEAMS ♦ LEPTONS ♦ PARTICLE BEAMS ♦ PLASMA HEATING ♦ SORPTION
Abstract Power deposition from electrons in capacitively coupled plasmas (CCPs) has components from stochastic heating, Joule heating, and from the acceleration of secondary electrons through sheaths produced by ion, electron, or photon bombardment of electrodes. The sheath accelerated electrons can produce high energy beams which, in addition to producing excitation and ionization in the gas can penetrate through the plasma and be incident on the opposite electrode. In the use of CCPs for microelectronics fabrication, there may be an advantage to having these high energy electrons interact with the wafer. To control the energy and increase the flux of the high energy electrons, a dc bias can be externally imposed on the electrode opposite the wafer, thereby producing a dc-augmented CCP (dc-CCP). In this paper, the characteristics of dc-CCPs will be discussed using results from a computational study. We found that for a given rf bias power, beams of high energy electrons having a narrow angular spread (<1 deg. ) can be produced incident on the wafer. The maximum energy in the high energy electron flux scales as {epsilon}{sub max}=-V{sub dc}+V{sub rf}+V{sub rf0}, for a voltage on the dc electrode of V{sub dc}, rf voltage of V{sub rf}, and dc bias on the rf electrode of V{sub rf0}. The dc current from the biased electrode must return to ground through surfaces other than the rf electrode and so seeks out a ground plane, typically the side walls. If the side wall is coated with a poorly conducting polymer, the surface will charge to drive the dc current through.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2010-01-15
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 107
Issue Number 2


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