Patent ID: 6229264
Filing Date: 2001-05-08
Classification: H01J,H05H

Abstract:
A method of controlling an r.f. plasma treating one or more workpieces in a vacuum plasma processing chamber, the workpiece being on a workpiece holder, the method being performed in accordance with one of plural recipes each including a set of parameters, the parameters associated with each recipe including (a) flow rate of gas supplied to the chamber, (b) pressure in the chamber, (c) power supplied to a multi-turn excitation coil for the plasma, and (d) a function determined by a desired coupling coefficient of an r.f. field component the coil is to apply to the plasma, the method comprising processing a workpiece in accordance with a first of the recipes with the coupling coefficient adjusted so there is a first relation between r.f. field components coupled from different portions of the coil to the plasma, and thereafter processing a workpiece in accordance with a second of the recipes with the coupling coefficient adjusted so there is a second relation between r.f. field components coupled between different portions of the coil and the plasma, the coupling coefficient being adjusted by varying the spacing between different radial portions of the coil and the plasma in a direction substantially at right angles to a plane including radii of the coil.