Methods and apparatus for glitch recovery in stationary-beam ion implantation process using fast ion beam control

A method of operating a stationary-beam ion implanter to fill in an under-dosed area of a semiconductor wafer between first and second implantation transition locations on the wafer, comprising:

• reducing the current of an ion beam to a reduced ion beam current equal to a predetermined fraction of a normal ion beam current;
• mechanically scanning a first normally dosed area of the wafer across the reduced-current ion beam at a normal or higher scanning speed until the first implantation transition location is reached;
• when the first implantation transition location is reached, reducing the mechanical scanning speed of the wafer to a reduced scanning speed substantially equal to the predetermined fraction of the normal scanning speed;
• scanning the wafer across the reduced-current ion beam at the reduced scanning speed from the first implantation transition location to the second implantation transition location;
• and
• when the second implantation transition location is reached, increasing the mechanical scanning speed of the wafer to the normal scanning speed or higher, and mechanically scanning the wafer across the reduced current ion beam at the normal or higher scanning speed away from the second implantation location across a second normally dosed area of the wafer.

A stationary-beam ion implanter operative to perform an ion implantation in a semiconductor wafer, comprising:

• a source of a stationary, planar ion beam;
• a plurality of beamline components operative to steer the ion beam along a normal beam path as determined by respective first values of respective operating parameters of the beamline components;
• an end station operative to mechanically scan the wafer across the normal beam path;
• and
• control circuitry operative, in response to detecting a glitch in the ion beam during the implantation pass, to:
• substantially immediately alter at least one operating parameter of at least one of the beamline components to a respective second value effective to direct the ion beam away from the normal beam path and thereby cease implantation of the wafer at an implantation transition location on the wafer;
• while the ion beam is directed away from the normal beam path, move the wafer to an implantation-resuming position in which the implantation transition location on the wafer lies directly on the normal path of the ion beam;
• and
• as the wafer reaches the implantation-resuming position, substantially immediately return the at least one operating parameter of the at least one beamline component to its respective first value to thereby direct the ion beam along the normal beam path and resume ion implantation at the implantation transition location on the wafer.

A stationary-beam ion implanter operative to fill in an under-dosed area of a semiconductor wafer, comprising:

• a source of an ion beam;
• an end station operative to mechanically scan the wafer across a path of the ion beam;
• and
• control circuitry operative to:
• reduce the current of an ion beam to a reduced ion beam current equal to a predetermined fraction of a normal ion beam current;
• mechanically scan a first normally dosed area of the wafer across the reduced-current ion beam at a normal or higher scanning speed until the first implantation transition location is reached;
• when the first implantation transition location is reached, reduce the mechanical scanning speed of the wafer to a reduced scanning speed substantially equal to the predetermined fraction of the normal scanning speed;
• scan the wafer across the reduced-current ion beam at the reduced scanning speed from the first implantation transition location to the second implantation transition location;
• and
• when the second implantation transition location is reached, increase the mechanical scanning speed of the wafer to the normal scanning speed or higher, and mechanically scanning the wafer across the reduced-current ion beam at the normal or higher scanning speed away from the second implantation location across a second normally dosed area of the wafer.

A method of operating a stationary-beam ion implanter to perform an ion implantation in a workpiece, comprising:

• performing an implantation pass by mechanically scanning the workpiece across a normal beam path, the normal beam path being traveled by a stationary, planar ion beam as determined by respective first values of respective operating parameters of a plurality of beamline components;
• in response to detecting a glitch in the ion beam during the implantation pass, substantially immediately altering at least one operating parameter of at least one of the beamline components to a respective second value effective to direct the ion beam away from the normal beam path and thereby cease implantation of the workpiece at an implantation transition location on the workpiece;
• while the ion beam is directed away from the normal beam path, moving the workpiece to an implantation-resuming position in which the implantation transition location on the workpiece lies directly on the normal path of the ion beam;
• and
• as the workpiece reaches the implantation-resuming position, substantially immediately returning the at least one operating parameter of the at least one beamline component to its respective first value to thereby direct the ion beam along the normal beam path and resume ion implantation at the implantation transition location on the workpiece.