Patent ID: 8419892

Claim:
A plasma process detecting sensor comprising: a substrate; a first electrode selectively formed over the substrate in a state of being insulated from the substrate; a first insulating film formed over the first electrode; a second insulating film deposited over the first insulating film; a second electrode selectively formed over a top surface of the second insulating film and exposed to a plasma during plasma etching; a first opening formed in the second electrode; a contact hole defined in the second insulating film and having a depth that extends from the first opening to a top surface of the first insulating film, a diameter of the contact hole on the top surface of the second insulating film being larger than the first opening; a second opening formed in the first insulating film located below the contact hole and having a diameter smaller than the diameter of the first opening; and a measuring device for measuring a difference in potential between the first and second electrodes during the plasma etching.