Plasma reactive ion etching of aluminum and aluminum alloys

A composition of matter for selective etching of pure aluminum material consisting essentially of a quaternary mixture of boron trichloride (BCl.sub.3) as a major constituent and chlorine (Cl.sub.2), silicon tetrafluoride (SiF.sub.4), and oxygen (O.sub.2) as the minor constituents, wherein said BCl.sub.3 constitutes 40 to 65% by volume of the mixture, Cl.sub.2 constitutes 15 to 30% by volume, SiF.sub.4 constitutes 10-25% by volume, and O.sub.2 constitutes 2 to 5% by volume of the mixture.

A process for selective reactive ion etching of thin films of sputtered metal aluminum in the presence of an etch mask, within a reaction chamber, comprising the step of:

• exposing said aluminum metallization within the chamber to a gas plasma for etching, wherein said gas plasma consists essentially of a quarternary mixture of boron trichloride (BCl.sub.3) as a major constituent and chlorine (Cl.sub.2), silicon tetrafluoride (SiF.sub.4), and oxygen (O.sub.2) as the minor constituents, wherein said BCl.sub.3 constitutes substantially 61% by volume of the mixture, Cl.sub.2 constitutes substantially 19% by volume, SiF.sub.4 constitutes substantially 17% by volume, and O.sub.2 constitutes substantially 3% by volume of the mixture.

A process for selective reactive ion etching of thin films of electron beam evaporated aluminum/silicon alloys in the presence of an etch mask, within a reaction chamber, comprising the step of:

• exposing said aluminum alloy metallization within the chamber to a gas plasma for etching, wherein said gas plasma consists essentially of a mixture of boron trichloride (BCl.sub.3) as a major constituent and chlorine (Cl.sub.2), silicon tetrafluroide (SiF.sub.4), and oxygen (O.sub.2) as the minor constituents, wherein said BCl.sub.3 contitutes substantially 64% by volume of the mixture, Cl.sub.2 constitutes substantially 17% by volume, SiF.sub.4 constitutes substantially 15% by volume, and O.sub.2 constitutes substantially 4% by volume of the mixture.

A process for selective reactive ion etching of thin films of a sputtered aluminum/silicon alloy in the presence of an etch mask, within a reaction chamber, comprising the step of:

• exposing said aluminum metallization within the chamber to a gas plasma for etching, wherein said gas plasma consists essentially of a mixture of boron trichloride (BCl.sub.3) as a major constituent and chlorine (Cl.sub.2), silicon tetrafluoride (SiF.sub.4), and oxygen (O.sub.2) as the minor constituents, wherein said BCl.sub.3 constitutes substantially 61% by volume of the mixture, Cl.sub.2 constitutes substantially 19% by volume, SiF.sub.4 constitutes substantially 17% by volume, and O.sub.2 constitutes substantially 3% by volume of the mixture.

A process for selective reactive ion etching of thin films of a sputtered alloy of aluminum/silicon/copper in the presence of an etch mask, within a reaction chamber, comprising the step of:

• exposing said aluminum metallization within the chamber to a gas plasma for etching, wherein said gas plasma consists essentially of a mixture of boron trichloride (BCl.sub.3) as a major constituent and chlorine (Cl.sub.2), silicon tetrafluoride (SiF.sub.4), and oxygen (O.sub.2) as the minor constituents, wherein said BCl.sub.3 constitutes substantially 58% by volume of the mixture, Cl.sub.2 constitutes substantially 15% by volume, SiF.sub.4 constitutes substantially 21% by volume, and O.sub.2 constitutes substantially 3% by volume of the mixture.