Bell Telephone Laboratories

Cyril J Mogab

Hyman J Levinstein

Ashok K Sinha

Bertram Schwartz

Louis A Koszi

Robert Louis Hartman

Richard S Wagner

Cesar D Capio

Roy A Porter

Frank B Alexander, Jr

William R Harshbarger

James Edward Griffiths

Victor Emerald Hauser, Jr

Eugene O Degenkolb

The endpoints of plasma discharge processing operations (e.g., plasma stripping of photoresists and plasma etching) are determined by monitoring the light produced in the space surrounding the object being processed. The optical monitor includes a wavelength selective device which is adjusted to transmit light from a selected excited species, which includes particles from the surface being processed. The surface includes a layer of one material overlaying a second material. If the selected excited species includes particles of the first material, then the endpoint of the removal operation occurs when the monitored intensity falls below a predetermined threshold level. When the selected excited species includes particles of the second material, then the endpoint occurs when the monitored intensity rises above a preselected threshold level.

Method for the optical monitoring of plasma discharge processing

Plasma etching is described as a selective etch for dielectric masks such as SiO.sub.2, Si.sub.3 N.sub.4 and certain photoresists in the presence of native oxides of Group III-V compound semiconductors. This process can be used in the fabrication of mesa junction lasers and Burrus light emitting diodes.

Selective plasma etching of dielectric masks in the presence of native

Plasma etching as applied to many of the materials encountered in the fabrication of LSI's is complicated by loading effect--the dependence of etch rate on the integrated surface area to be etched. This problem is alleviated by appropriate choice of etchant and etching conditions. Appropriate choice of system parameters, generally most concerned with the inherent lifetime of etchant species, may also result in improvement of etch rate uniformity on a wafer-by-wafer basis.

Device fabrication by plasma etching

Integrated circuit fabrication, e.g., silicon LSI is expedited by plasma etching in any of a novel class of etchants. Appropriate plasma environments are produced by introduction of fluorocarbon-halogenation combinations as exemplified by CF.sub.3 Cl.

High density fine-line integrated structure fabrication is expedited by use of plasma etching systems which assure straight vertical walls (absence of undercutting). Critical to the sytems is choice of appropriate plasma chemistry. Appropriate systems are characterized by inclusion of recombination centers, as well as active etchant species. Recombination centers which effectively terminate etchant species lifetime in the immediate vicinity of resist walls afford means for controlling etching anisotropy. Use is foreseen in large scale integrated circuitry (LSI) and is expected to be of particular interest for extremely fine design rules, i.e., in Very Large Scale Integrated circuitry.

An improved radio frequency (rf) powered radial flow cylindrical reactor utilizes a gas shield which substantially limits the glow plasma discharge reaction to a section of the reactor over the semiconductor substrates which are to be coated. The gas shield permits the use of higher rf input power which contributes to the formation of protective films that have desirable physical and electrical characteristics.

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Berkeley Heights, NJ, United States of America

Cyril J Mogab