Capacitive sensor for chamber condition monitoring

A sensor module, comprising:

• a sensor substrate with a first surface and a second surface opposite from the first surface;
• a first electrode over the first surface of the sensor substrate;
• a second electrode over the first surface of the sensor substrate and adjacent to the first electrode;
• and
• a capacitance-to-digital converter (CDC) electrically coupled to the first electrode and the second electrode.

A processing tool, comprising:

• a chamber defining an interior volume, wherein the interior volume comprises a processing region and an evacuation region;
• a lid to seal the chamber;
• a substrate support within the processing region, the substrate support for supporting a substrate and a process ring;
• and
• a capacitive sensor within the interior volume, wherein the capacitive sensor comprises:
• a substrate having a first surface and a second surface opposite from the first surface;
• a first electrode over the first surface of the substrate;
• a second electrode over the first surface of the substrate and adjacent to the first electrode;
• and
• a barrier layer over the first electrode and the second electrode.