Patent ID: 11908665
Assignee: TOKYO ELECTRON LIMITED
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 17:
18. A plasma processing apparatus, comprising:
a chamber;
a substrate support accommodated in the chamber;
an electric path coupled to or capacitively coupled to an edge ring on the substrate support; and
a measuring device configured to measure an electrical characteristic value of the edge ring with a voltage applied to the edge ring on the substrate support through the electric path, the electrical characteristic value being variable in accordance with a thickness of the edge ring, wherein
the measuring device measures the electrical characteristic value with a direct-current voltage applied to the edge ring through the electric path coupled to the edge ring,
the electrical characteristic value includes a resistance of the edge ring,
the electric path includes a first contact and a second contact in contact with the edge ring at positions symmetric to each other about a central axis of the edge ring,
the measuring device includes
a current sensor located on the electric path and configured to measure a current value of a current flowing through the edge ring,
a first voltage sensor configured to measure a first potential difference across a first area of the edge ring, the first area extending in a first part of a plane including the first contact, the second contact, and the central axis, and
a second voltage sensor configured to measure a second potential difference across a second area of the edge ring, the second area extending in a second part of the plane, and

the measuring device determines the resistance based on an average of the first potential difference and the second potential difference and on the current value.