Reactive sputter etching of Si, SiO/sub 2/, Cr, Al, and other materials with gas mixtures based on CF/sub 4/ and Cl/sub 2/

Journal Article · Sun Nov 01 04:00:00 EST 1981 · J. Vac. Sci. Technol.; (United States)

DOI:https://doi.org/10.1116/1.571220· OSTI ID:5958272

Horwitz, C M; Melngailis, J

All etching processes require control of the relative etch rates of the mask and substrate materials. This is especially important in vacuum-etching processes where directional etching is often obtained at the expense of increased mask etch rate. Etch rate control requires good control of the etching parameters, and here at a constant gas flow of 2 x 10/sup -2/ Pa m/sup 3//s we use target voltage (peak-to-peak) and partial pressure of reactant species as controlled variables rather than power density and total pressure, as is common practice. SiO/sub 2/ and Si etch rates in CF/sub 4/ with a Si target were found to vary as P/sup 1/2/V/sup 2/ where V is the peak-to-peak target voltage (varied between 0.6 kV and 2.9 kV) and P is the reactant gas pressure varied between 0.35 Pa (2.7 ..mu..m) and 14.3 Pa (110 ..mu..m). Cr and Al rates varied as V/sup 3/, but were almost independent of pressure. These differences enable accurate selection of relative etch rates and appropriate masks. For instance, SiO/sub 2//Cr etch rate ratios as high as 50:1 may be achieved for 3.7 Pa of CF/sub 4/ at 0.8 kV peak-to-peak target voltage. Chlorine mixed with CF/sub 4/ enables the properties of the two gases to be combined. Thus, by adjusting only the gas mixture from pure CF/sub 4/ to pure Cl/sub 2/, the Si/SiO/sub 2/ etch rate ratio can be continuously varied between 0.33 and 6, respectively, at 1.3 kV peak-to-peak target voltage, 3.7 Pa pressure, and with substrates on a Si target.

• Research Organization: Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• OSTI ID: 5958272
• Journal Information: J. Vac. Sci. Technol.; (United States), Journal Name: J. Vac. Sci. Technol.; (United States) Vol. 19:4; ISSN JVSTA
• Country of Publication: United States
• Language: English

Related Subjects

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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALUMINIUM
CARBON TETRACHLORIDE
CHALCOGENIDES
CHLORINATED ALIPHATIC HYDROCARBONS
CHLORINE
CHROMIUM
ELECTRIC POTENTIAL
ELEMENTS
ETCHING
FLUID FLOW
FLUIDS
GAS FLOW
GASES
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENS
HELIUM
HYDROGEN
METALS
MINERALS
NONMETALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRESSURE MEASUREMENT
RARE GASES
SEMIMETALS
SILICA
SILICON
SILICON COMPOUNDS
SILICON OXIDES
SPUTTERING
SURFACE FINISHING
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
VAPOR PRESSURE