Patent ID: 7922862
Filing Date: 2011-04-12
Classification: H01J,H01L

Abstract:
1. A plasma processing apparatus for performing a plasma process on a target substrate essentially having a circular contour, the apparatus comprising: a process container configured to accommodate the target substrate and to reduce pressure therein; a first electrode and a second electrode disposed opposite each other within the process container, the first electrode being an upper electrode, and the second electrode being a lower electrode on which the target substrate is placed; a gas supply system configured to supply a process gas into the process container; a radio frequency (RF) power supply connected to the first electrode or the second electrode and configured to apply an RF power thereto for generating plasma of the process gas between the first and second electrodes; a circular dielectric portion embedded in the first electrode and defining a central part of a lower surface of the first electrode that is exposed to plasma during the plasma process, the dielectric portion being concentric with the first electrode and having a thickness larger at an electrode central portion than at an electrode edge portion; and a plurality of detachable conductive shield rings with variable widths so that when one of said conductive shield rings is disposed on the lower surface of the first electrode to be concentric with the dielectric portion, said one conductive shield ring covers the electrode and a periphery of the dielectric portion leaving a controlled opening with a required diameter to expose a central portion of the dielectric portion while covering a peripheral portion of the dielectric portion, the diameter of the opening being used as a parameter for adjusting a distribution characteristic of electric field intensity between the first and second electrodes.