Plasma etching apparatus utilising plasma confinement

摘要

The plasma processing unit comprises a housing containing a gaseous medium useful for processing a workpiece and a parallel pair of electrodes defining between them an interaction space where a plasma capable of processing a workpiece supported on one of the electrodes is generated when radio-frequency energy is provided for establishing a discharge between the electrodes and ionising the gaseous medium. A confinement assembly defines a series of separate parallel passages that allow gas flow through the confinement assembly from an inner surface to an outer surface, the parallel passages being spaced apart in a direction normal to that of the flow of gases through the passages, the confinement assembly is between the electrode. The passages proportional for confining the discharge within the interaction space to neutralising charged particles created in the plasma when the charged particles pass through the passages. The confinement assembly comprises a dielectric, in right circular cylinder form. The separate parallel passages extending through the confinement assembly are radial passages.