Method and apparatus for plasma processing a workpiece in an enveloping plasma

摘要

A plasma heating apparatus for heating a workpiece includes a chamber of sufficient size to receive a workpiece therein and a source of a reduced gas pressure within the chamber of from about 0.01 to about 100 millitorr. The plasma heating apparatus further includes a plasma source of an enveloping plasma. Optionally, a workpiece voltage may be applied between the workpiece and the wall of the chamber, and a source of a reactive gas can be provided to backfill the chamber, and radiant heaters can be provided to independently heat portions of the workpiece. In operation, the plasma source produces a plasma that surrounds and heats the workpiece. The plasma and the heating of the workpiece are tailored to achieve controllably uniform or nonuniform heat treatment and/or surface treatment of the workpiece. The apparatus can be used to heat treat the workpiece in vacuum, or a reactive gas such as a gaseous source of nitrogen, carbon, or boron can be backfilled into the chamber to alter the surface chemistry of the workpiece.