Technique and apparatus for monitoring ion mass, energy, and angle in processing systems

An ion implantation system, comprising:

• a plasma source configured to generate a plasma at a plasma potential in a plasma chamber, the plasma source comprising a plasma sheath modifier and an aperture defined in the plasma sheath modifier, the aperture having a width in a first direction;
• a substrate holder operable to position a substrate in a substrate plane of a substrate region and to receive a substrate potential, wherein the plasma chamber supplies an ion beam into the substrate region containing ions incident over a range of angles at an energy defined by a difference in a potential of the plasma and a potential of the substrate;
• and
• a time-of-flight (TOF) ion sensor system disposed near the substrate holder, said TOF ion sensor system including:
• a TOF sensor comprising a drift tube having a first end operable to receive the ions in the substrate region generated by the plasma chamber and configured to receive the substrate potential, the TOF sensor including a detector disposed at a second end of the drift tube;
• and
• a positioner configured to vary an angle of the TOF sensor by rotating the drift tube through a first angular range with respect to the substrate plane in a first series of TOF measurements, move the TOF sensor along the first direction and conduct a second series of TOF measurements of ions by rotating the drift tube through a second angular range.

A method of measuring ion species incident upon a substrate plane received from a plasma comprising:

• generating the plasma in a plasma chamber, the plasma chamber comprising a plasma sheath modifier and an aperture defined in the plasma sheath modifier, the aperture having a width along a first direction;
• applying a first potential between the plasma and a time-of-flight (TOF) sensor, the TOF sensor comprising a drift tube extending in a second direction orthogonal to the first direction, a first end configured to receive ion species generated in the plasma chamber and a detector disposed at a second end of the drift tube;
• attracting the ion species to the detector of the TOF sensor at a designated ion energy;
• performing a series of TOF measurements of ions by rotating the drift tube through a first angular range;
• moving the detector in a third direction orthogonal to the first and second directions such that the detector remains at a set position with respect to the first direction;
• moving the TOF sensor along the first direction;
• and
• performing a further series of TOF measurements of ions by rotating the drift tube through second angular range.