Systems and methods for detecting endpoint for through-silicon via reveal applications

A plasma processing system for determining endpoint of a plasma etching operation on a top surface of a semiconductor wafer, comprising:

• a plasma processing chamber having an exterior, an interior region equipped with a wafer receiving mechanism for receiving the semiconductor wafer, and at least two viewports providing visual access from the exterior to the top surface of the semiconductor wafer when received on the wafer receiving mechanism, wherein the viewports are disposed on side walls of the plasma processing chamber;
• a camera mounted to each of the two viewports of the plasma processing chamber on the exterior, each of the cameras configured to take sequential images of a pattern emerging on the top surface of the semiconductor wafer during an active etching operation, the cameras acting as stereo camera to provide three dimensional view of the emerging pattern;
• an external light source coupled to each of the cameras, light pulse from each of the external light source directed toward the top surface of the semiconductor wafer within the plasma processing chamber to illuminate the pattern emerging on the semiconductor wafer for the cameras during capturing of the images;
• and
• a processor coupled to the cameras and the plasma processing chamber, the processor equipped with a pattern recognition logic configured to detect the emerging pattern from the images captured and transmitted by the cameras at regular intervals, match the emerging pattern to a reference pattern and generate a signal identifying endpoint, when a match is detected, the generated signal causing the etch operation to stop.