Abstract: An improved etchant gas composition for the plasma etching of a layer of aluminum or its alloys on a substrate is provided. The etchant composition comprises boron trichloride, nitrogen and a halogenated fluorocarbon. In addition to providing an efficient, anisotropic etch, the subject etchant compositions form a passivating coating on aluminum reactor walls, protecting them from being etched and substantially reducing contamination problems. The subject compositions etch aluminum/silicon alloys without leaving a residue of slilicon "freckles" on the substrate surface.

Abstract: A method of improving uniformity of etching in the plasma etching of a substrate of aluminum and its alloys by supporting the substrate on a getter plate of a metal such as tantalum. The getter plate extends beyond the substrate for a distance sufficient to improve the uniformity of etching across the substrate.

Abstract: A method of improving the uniformity and line-width control in the plasma etching of aluminum and its alloys by adding to the etchant gas an effective amount of a gaseous hydrocarbon which will polymerize under glow discharge conditions.

Abstract: An improvement in the etching of aluminum utilizing a carbon-containing etchant gas is provided whereby the residues remaining after etching are treated in a nitrogen glow discharge for a time effective in removing them or rendering them susceptible to removal by conventional means.

Abstract: A method of anisotropic etching of aluminum or an alloy thereof comprising using as the etch gas a mixture of boron trichloride, trichloromethane and hydrogen. The etchant mixture advantageously also contains nitrogen and helium.

Abstract: A method of forming an adherent pinhole free aluminum film on a pyroelectric and/or piezoelectric substrate comprising heating said substrate to from about 150.degree. C. to about 350.degree. C. at a pressure of from about 1.times.10.sup.-4 Torr to about 1.times.10.sup.-6 Torr for a sufficient time to desorb any gas molecules on the surface on said substrate, cooling said substrate with dry oxygen to about 125.degree. C. at a pressure of about 1.times.10.sup.-4 Torr and thereafter, terminating the flow of oxygen and further reducing the pressure to about 1.times.10.sup.-5 Torr or lower and evaporating an aluminum film on said substrate.