US Patent 10224182 Mechanical suppression of parasitic plasma in substrate processing chamber

A system for reducing parasitic plasma in a semiconductor process comprises a first surface and a plurality of dielectric layers that are arranged between an electrode and the first surface. The first surface and the electrode have substantially different electrical potentials. The plurality of dielectric layers defines a first gap between the electrode and one of the plurality of dielectric layers, a second gap between adjacent ones of the plurality of dielectric layers, and a third gap between a last one of the plurality of dielectric layers and the first surface. A number of the plurality of dielectric layers and sizes of the first gap, the second gap and the third gap are selected to prevent parasitic plasma between the first surface and the electrode during the semiconductor process.