Patent ID: 8715789
Filing Date: 2014-05-06
Classification: C23C,H01J,Y10T

Abstract:
1. A method for plasma enhanced chemical vapor deposition (CVD) to an interior surface of a hollow tubular high aspect ratio workpiece, the method comprising simultaneously coating the entire interior surface as a single section by: providing at least three anodes in axially spaced apart arrangement along an entire lengthwise axis of an elongated interior of a hollow tubular workpiece of high aspect ratio greater than or equal to about thirty to one; providing an elongated support tube dimensioned to reside in the elongated interior of the workpiece along its entire length and arranging the anodes in spaced apart relation inside of the elongated support tube, wherein a ratio of a spacing between anodes to an interior diameter of the hollow tubular workpiece is between about twenty to one and about one to one; the workpiece being biased as a cathode and the elongated support tube is allowed to float electrically or be biased as a cathode so to form a plasma region in the interior of the workpiece between the support tube and workpiece, the support tube having a set of holes therein on all sides situated in proximity to the anodes within the support tube so as to allow electron flow between anodes and the plasma region; introducing a CVD process gas into the entire plasma region in the interior of the workpiece; applying a respective individualized DC or pulsed DC bias to each of the plurality of anodes to excite the process gas into a plasma; and controlling a pressure of the process gas in the interior of the workpiece to maintain a plasma.