| 摘要 |
The method comprises the steps of placing a workpiece on an electrode disposed in a processing chamber; introducing an etching gas into the processing chamber; exciting the etching gas to generate a plasma ; and applying a periodical voltage to the electrode which wave has a first portion with a voltage that electrons are allowed to impinge on the workpiece and a second portion corresponding with voltage for accelerating positive ions toward the workpiece, which voltage includes a first constant component for generating an accelerating field and a second increasing component for coancelling the increasing effect of charge-up at the workpiece surface.
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