AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS2-MoA

Paper PS2-MoA8
Plasma Sheath Electric Field Strengths Above a Grooved Electrode in a Parallel-Plate Radio Frequency Discharge

Monday, November 2, 1998, 4:20 pm, Room 318/319/320

Session: Diagnostics I
Presenter: U. Czarnetzki, Universitaet GH Essen, Germany
Authors: U. Czarnetzki, Universitaet GH Essen, Germany
G.A. Hebner, Sandia National Laboratories
D. Luggenholscher, Universitaet GH Essen, Germany
H.F. Dobele, Universitaet GH Essen, Germany
M.E. Riley, Sandia National Laboratories
Correspondent: Click to Email
During plasma etching of microelectronic structures, the direction and energy of the ions that strike the surface has a major influence on the characteristics of the etch profile. In an ideal case, the sheath electric field vector will be perfectly perpendicular to the surface so that ions accelerated from the bulk plasma above the wafer will strike the wafer surface at normal incidence. In reality, the wafer surface is a multidimensional surface with several layers of subsurface dielectric that can significantly modify the electric field direction and ion trajectories. To examine the details of the spatial distribution of the electric field strength in the sheath region above an electrode with surface structure, and to provide data to validate recent advances in multidimensional sheath models, we have measured sheath electric fields above a structured electrode. The magnitude of the sheath electric field above a grooved electrode was measured using a novel, two color, laser induced fluorescence technique. Spatially resolved electric fields in the sheath region were determined by mapping the field induced Stark splitting of the n = 14 level in atomic hydrogen. Measured electric field values are in good agreement with calculated values. This work was performed at the University of Essen. GAH thanks the Deutsche Forschungsgemeinschaft for a travel grant in the frame of the SFB 191. GAH and MER were supported by the United States Department of Energy (DE-AC04-94AL85000). Expert technical support by Rainer Fuhrer is gratefully acknowledged.