Modeling of magnetically enhanced capacitively coupled plasma sources: Two frequency discharges

Journal Article · Sat Sep 15 04:00:00 EDT 2007 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.2771558· OSTI ID:21020876

Yang, Yang; Kushner, Mark J ^[1]

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1. Department of Electrical and Computer Engineering, Iowa State University, 104 Marston Hall, Ames, Iowa 50011 (United States)

Magnetically enhanced, capacitively coupled radio frequency plasma sources are finding continued use for etching of materials for microelectronics fabrication at a time when multifrequency sources are also being developed. Magnetically enhanced reactive ion etching (MERIE) sources typically use magnetic fields of tens to hundreds of Gauss parallel to the substrate to either increase the plasma density at a given pressure or to lower the operating pressure. Multifrequency sources are used to separately control the magnitude of the ion and radical fluxes (typically with a high frequency source) and the ion energy distributions (typically with a low frequency) to the substrate. In this article, the properties of a two-frequency MERIE reactor are discussed using results from a computational investigation. As in single frequency sources, the reduction in transverse electron mobility as the magnetic field increases can produce a reversal of the electric field in the sheath and an increase in voltage drop across the bulk plasma. These trends decrease ion energies and increase the angular spread of ions. Similar trends are found here, including a field reversal in the sheath at the high frequency electrode. These effects produce a coupling between the high and low frequency sources that compromise the independence of ion production and ion acceleration by the two sources.

• OSTI ID: 21020876
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films Journal Issue: 5 Vol. 25; ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRIC FIELDS
ELECTRON MOBILITY
ENERGY SPECTRA
ETCHING
HIGH-FREQUENCY DISCHARGES
IONS
MAGNETIC FIELDS
PLASMA
PLASMA DENSITY
PLASMA SHEATH
RADIOWAVE RADIATION
SIMULATION
SUBSTRATES
VOLTAGE DROP
WALL EFFECTS