Plasma unconfinement sensor and methods thereof

A method for detecting a plasma unconfinement event during plasma processing within a plasma reactor, said method comprising:

• detecting, via a sensor, a transient current when said sensor is exposed to plasma associated with said plasma unconfinement event, wherein
• said sensor is a capacitive-based sensor implemented within said plasma reactor and outside of a plasma confinement region,
• said sensor comprises an outer layer and an outer surface,
• said outer layer comprises at least one electrically insulative layer, wherein said outer layer surrounds a substrate or is partially disposed between said substrate and a chamber wall of said plasma reactor, and
• said outer surface is oriented toward said plasma associated with said plasma unconfined event;
• converting said transient current into a transient voltage signal by a detection circuit, wherein said detection circuit is electrically connected to said sensor;
• and
• processing said transient voltage signal to indicate whether said plasma unconfinement event exists.

A sensor comprising:

• a conductive substrate configured to be mounted on a surface of a chamber wall and internal to a plasma reactor;
• an outer layer disposed on said conductive substrate, wherein said outer layer comprises
• a first insulative layer disposed on said conductive substrate,
• a second insulative layer disposed on said first insulative layer, and
• an outer surface configured to be exposed to plasma in said plasma reactor;
• an insulator, wherein a first portion of said insulator is configured to extend through said chamber wall, and wherein a second portion of said insulator is disposed between said outer layer and said chamber wall;
• a contact connected to said conductive substrate, wherein said contact extends through said first portion of said insulator;
• and
• a conductive element configured to connect said contact to a detection circuit,
• wherein said conductive substrate extends outward away from said contact such that a portion of said outer surface is exposed to said plasma, and wherein said portion of said outer surface faces said chamber wall.