Apparatus for, and method of, providing a deposition on a substrate

Abstract

A target, preferably frusto-conical, defines a cavity with an anode. Molecules of a neutral gas (e.g. argon) pass through the cavity at a particular rate. An alternating voltage is applied between the anode and the cathode. When the anode voltage is positive relative to the cathode, electrons are emitted from the cathode and are directed to the anode. A magnetic field is produced on the electrons in a direction transverse, preferably substantially perpendicular, to the electrical field. The magnetic field causes the electrons to travel in a spiral path between the anode and the target, thereby enhancing the ionization rate of the argon molecules passing through the cavity. The positive argon ions impinge on the target and cause atoms to be sputtered from the target surface. These atoms become deposited on a surface of a substrate displaced from the target. When the anode voltage is negative, the discharge is extinguished and electrons travel in the spiral path toward the target (which is now positive) and discharges any positive charge buildup on the target. Two of the assemblies as disclosed above may be angularly displaced, preferably by substantially 180.degree., from each other relative to an axis on which the substrate is located. Each anode and the target associated with the other anode have a common connection with the source of the alternating voltage.