System and method for spatially resolved optical metrology of an ion beam

A system for spatially resolved optical metrology of an ion beam, the system comprising:

• a chamber containing a plasma source operable to deliver an ion beam to a wafer;
• a first plate having a first aperture for receiving a measured light signal from a sample of the ion beam;
• a second plate adjacent the first plate, the second plate having a second aperture for receiving the measured light signal through the first plate;
• and
• a detector operable to receive the light signal from the second plate and output an electric signal corresponding to the measured light signal.

A method comprising:

• delivering an ion beam to a wafer;
• measuring a light signal from a portion of the ion beam by an optical device;
• receiving the measured light signal through a first aperture of a first plate, wherein the first plate is positioned adjacent the optical device;
• receiving the measured light signal through a second aperture of a second plate, wherein the second plate is positioned adjacent the first plate;
• receiving, at a detection module, the measured light signal from the second plate;
• and
• outputting an electric signal from the detection module, the electric signal corresponding to the measured light signal.