High energy electron fluxes in dc-augmented capacitively coupled plasmas I. Fundamental characteristics

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3290870· OSTI ID:21476101

Mingmei, Wang ^[1]; Kushner, Mark J ^[2]

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1. Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50010 (United States)
2. Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

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.

• OSTI ID: 21476101
• Journal Information: Journal of Applied Physics, Vol. 107, Issue 2; Other Information: DOI: 10.1063/1.3290870; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 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