Determination of Ion Power Density during Reactive-Ion Etching from Temperature Measurements Using Laser Interferometry
Abstract
A method to determine the ion power density during reactive-ion etching using a laser interferometer is described. Thickness changes due to heating of thin (<0.3 centimeters) plate-glass substrates during RIE processing are monitored via interferometry. The thickness changes are directly related to temperature changes within the isothermal substrate, which allows the plate- glass temperature to be monitored accurately and non-intrusively. Ion energy flux determinations follow directly from the heating and cooling dynamics of the substrate. The measured ion energy fluxes are constant for all times during a run to within experimental error and are in good agreement with predictions given by the space-charge limited flux expression. The radio frequency power transfer efficiency, defined as the ion energy flux delivered to the cathode relative to the nominal rf input power, is less than 30%. The O2 (oxygen) RIE rate of poly(methyl methacrylate) and polystyrene were found to vary linearly with the measured ion energy flux to the surface over a broad range of processing conditions. (jg)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 07, 1990
- Accession Number
- ADA222065
Entities
People
- B. C. Dems
- Francisco J. Medellı́n-Rodrı́guez
Organizations
- Cornell University School of Chemical and Biomolecular Engineering