Particulate prevention in ion implantation

A method for controlling particle contamination in an ion implantation system, the method comprising the acts of:

• providing an ion source having a filament cathode and a mirror electrode;
• determining a position of a workpiece within the ion implantation system;
• supplying current to the filament cathode and mirror electrode of the ion source, therein forming an ion beam via an ionization of a precursor gas by electrons emitted from the filament cathode, wherein contaminants are generally formed within the ion implantation system when the ion beam is at an implantation current;
• controlling the current supplied to the mirror electrode, therein rapidly modulating a current of the ion beam between the implantation current and a minimal current, wherein the control is based, at least in part, on the position of the workpiece, and wherein the formation of contaminants within the ion implantation system is substantially reduced when the ion beam is at the minimal current.

An ion implantation system for implanting ions into a workpiece, the ion implantation system comprising:

• an ion source comprising a filament cathode and a mirror electrode and operable to form an ion beam;
• a power supply for supplying power to the filament cathode and mirror electrode of the ion source;
• an end station, wherein the workpiece generally resides in the end station during an ion implantation;
• a workpiece handing system operable to provide an ion beam control signal indicating the presence or absence of the workpiece in the end station;
• and
• a controller, wherein the controller is operable to control the power from the power supply to the ion source based on the ion beam control signal, and wherein a current of the ion beam is modulated between an implantation current and a minimal current in less than approximately 20 microseconds, wherein contaminants are generally formed by the ion beam at the implantation current, and wherein the formation of contaminants is generally reduced at the minimal current.