A Novel Plasma Tool for Large-Area Materials Processing

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Radio-frequency (RF) produced plasmas are widely used in industry for materials processing, ranging from the hardening of airplane wings to the machining of microscopic features within CPU semiconductor chips. The proposed work addresses the difficult problem of uniform plasma processing of materials over an arbitrarily large surface area through the use of a distributed source: an array of smaller source elements, each covering a small portion of the surface. Proof of principle experiments have been successful; optimization studies will now be performed to determine the scaling design rules for plasma processing tools of ever increasing size. Feasibility studies of uniformity control of large-area plasma through control of the individual sources will be periDrmed by using feedback control of the RF power to each antenna. Spacing between adjacent elements within the array will be varied to determine its optimum value. Permanent magnets will be used to create the individual magnetic fields that can enhance the plasma density, and thus the plasma processing rate, from each tube in a controlled fashion. Further optimization studies of the individual source elements themselves will also be performed in order to increase their overall effectiveness in a distributed array. Successful results would be of tremendous benefit to chip manufacturers, and to other industries that use plasma processing as well. A desirable outcome of the proposed work would be a set of design rules for the construction of arbitrarily large plasma tools that maintain sufficient process uniformity to be of use in the ever growing plasma processing industry. Furthermore, the present use of highly toxic substances in wet chemical processing of large area material surfaces would be reduced, and perhaps eliminated, in favor of the relatively benign plasma processing tools developed as a result of this work.