Electrode assembly having pierce electrodes for controlling space charge effects

An ion beam implantation system for implanting ions into a work piece, the system comprising:

• an ion source;
• an extraction manipulator configured to generate an ion beam by extracting ions from the ion source;
• an electrode assembly configured to accelerate or decelerate the ion beam, the electrode assembly comprising:
• a first ion beam path extending from a first opening of the electrode assembly to a second opening of the electrode assembly, wherein the first opening and the second opening are disposed on opposite sides of the electrode assembly;
• a pair of exit electrodes defining a portion of the first ion beam path adjacent to the second opening, the pair of exit electrodes positioned on opposite sides of a first plane aligned with a first dimension of the second opening;
• and
• a pair of pierce electrodes defining a portion of the first ion beam path adjacent to the pair of exit electrodes, the pair of pierce electrodes positioned on opposite sides of a second plane aligned with a second dimension of the second opening, wherein:
• the second dimension of the second opening is perpendicular to the first dimension of the second opening;
• each pierce electrode of the pair of pierce electrodes has an angled surface facing the first ion beam path;
• and
• the angled surface of each pierce electrode is positioned such that a first dimension of the angled surface of each pierce electrode forms an angle of between 40 and 80 degrees with respect to the second plane;
• and
• a work piece support structure configured to position the work piece in the ion beam, thereby implanting ions into the work piece.

A method for implanting ions into a work piece using an ion implantation system comprising an electrode assembly having pierce electrodes, the method comprising:

• generating an ion beam;
• decelerating the ion beam through the electrode assembly, the electrode assembly comprising:
• a first ion beam path extending from a first opening of the electrode assembly to a second opening of the electrode assembly, wherein the first opening and the second opening are disposed on opposite sides of the electrode assembly;
• a pair of exit electrodes defining a portion of the first ion beam path adjacent to the second opening, the pair of exit electrodes positioned on opposite sides of a first plane aligned with a first dimension of the second opening;
• and
• a pair of pierce electrodes defining a portion of the first ion beam path adjacent to the pair of exit electrodes, the pair of pierce electrodes positioned on opposite sides of a second plane aligned with a second dimension of the second opening, wherein:
• the second dimension of the second opening is perpendicular to the first dimension of the second opening;
• the pair of pierce electrodes each have an angled surface facing the first ion beam path;
• the angled surface of each pierce electrode is positioned such that a first dimension of the angled surface of each pierce electrode forms an angle of between 40 and 80 degrees with respect to the second plane;
• and
• the ion beam enters the electrode assembly through the first opening at a first energy, decelerates along the first ion beam path, and exits the electrode assembly through the second opening at a second energy that is lower than the first energy;
• and
• positioning the work piece in the ion beam to implant ions into the work piece.