PLASMA PROCESSING SYSTEM WITH GAS PERMEABLE ELECTRODE

摘要

Plasma processing system and electrode structure in which the electrode is highly permeable to the plasma so that the ionized gas can pass freely through the electrode to get to the workpiece. The electrode has a honeycomb structure with triangular openings separated by thin webs of sufficient height to impart torsional rigidity to the electrode. The electrode is loosely mounted in blocks which permit it to expand and contract with changes in temperature, and it has an outer peripheral portion which is segmented to accommodate thermal expansion. Sputtering problems are minimized by coating the electrode with a sacrificial material or a material which is less harmful to the plasma process.