Patent ID: 8871064

Claim:
In a plasma sputter reactor having a substrate support disposed in a plane perpendicular to an axis of a vacuum chamber having sidewalls formed around the axis and a sputter target arranged in opposition to the substrate support across a space along the axis, an electromagnet array of four electromagnet coils arranged at axial positions relative to the axis between the sputter target and the substrate support and all being configured to be connected to at least one DC power supply, wherein three electromagnet coils of the four electromagnet coils are arranged about the axis in a triangular array, wherein at least two of the three electromagnet coils are disposed at different radii from the axis and at least two of the three electromagnet coils are disposed at different axial positions relative to the axis, and wherein no more than two of the four electromagnet coils are disposed at a same radius from the axis and no more than two of the four electromagnet coils are disposed at a same axial position relative to the axis.