Approach to optimizing an ILD argon sputter process

A method of conducting a sputter etch:

• providing a semiconductor wafer having a wafer surface including a layer of dielectric material over a plurality of structures and a plurality of trenches;
• providing a sputter etch system including an etch chamber having a wafer pedestal with a top surface to support a wafer and a plurality of magnets coupled to said etch chamber and configured to provide a continuous magnetic field directed at and in a direction normal to said top surface of said wafer pedestal, wherein the plurality of magnets comprises an annular-shaped magnet surrounding a magnet that is other than annular shaped;
• placing said wafer on said pedestal;
• and
• exposing said wafer surface to a sputter etch, wherein the sputter etch includes redepositing into the plurality of trenches, a portion of the layer of dielectric material removed by the sputter etch from over the plurality of structures.