Patent attributes
An apparatus for providing a short return current path for RF current between a process chamber wall and a substrate support is provided. The RF grounding apparatus, which is RF grounded and is place above the substrate transfer port, establishes electrical contact with the substrate support only during substrate processing, such as deposition, to provide return current path for the RF current. One embodiment of the RF grounding apparatus comprises one or more low impedance flexible curtains, which are electrically connected to the grounded chamber wall, and to one or more low impedance blocks, which make contacts with the substrate support during substrate processing. Another embodiment of the RF grounding apparatus comprises a plurality of low impedance flexible straps, which are electrically connected to the grounded chamber wall, and to one or more low impedance blocks, which make contacts with the substrate support during substrate processing. Yet another embodiment of the RF grounding apparatus comprises a plurality of probes, which either are electrically connected to the grounded chamber wall or are grounded by other means, and actuators accompanying the probes. The actuators move the probes to make electrical contact with the substrate support during substrate processing.
