System and method for two-dimensional beam scan across a workpiece of an ion implanter
A workpiece or semiconductor wafer is tilted as a ribbon beam is swept up and/or down the workpiece. In so doing, the implant angle or the angle of the ion beam relative to the workpiece remains substantially constant across the wafer. This allows devices to be formed substantially consistently on the wafer. Resolving plates move with the beam as the beam is scanned up and/or down. This allows desired ions to impinge on the wafer, but blocks undesirable contaminants.
1. A system for implanting ions in a workpiece, the system comprising:
a beam generating component for generating an ion beam;
a mass resolving component for mass resolving the ion beam;
a sweeping component positioned downstream of the mass resolving component for sweeping the ion beam up and/or down an entirety of the workpiece along a sweeping axis;
a resolving aperture upstream of the workpiece and downstream of the sweeping component, and configured to move synchronously with the sweeping movement of the ion beam across the entirety of the workpiece so that desired ions of the ion beam pass therethrough, but contaminants are blocked thereby; and
an endstation configured to support the workpiece for implantation thereof, wherein the endstation is configured to tilt the workpiece along a beam axis synchronously with the sweeping motion of the ion beam so that a substantially constant implantation angle is maintained over the workpiece.
2. The system of claim 1 , further comprising:
a scanning component, positioned downstream of the mass resolving component, for scanning the ion beam across a scanning axis that is different than the sweeping axis.
3. The system of claim 2 , where the scanning component produces a time-averaged scanned pencil ion beam.
4. The system of claim 2 , where one component both scans and sweeps the ion beam.
5. The system of claim 2 , where one component scans the ion beam, and another component sweeps the ion beam.
6. The system of claim 1 , where the resolving aperture is defined by one or more resolving plates.
7. The system of claim 6 , where the resolving aperture moves synchronously with the sweeping movement of the ion beam by moving the resolving plates which define the aperture.
8. The system of claim 1 , where a scan pattern produced across the workpiece has a width that is at least as wide as the diameter of the workpiece.
9. The system of claim 1 , further comprising:
a measurement component configured to measure the implantation angle as the ion beam is swept up and down the workpiece; and
a controller operatively coupled to the measurement component, sweeping component, resolving plates and the workpiece, and configured to adjust the operation of at least one of the sweeping component, resolving plates, and the workpiece in response to measurements taken by the measurement component.
10. The system of claim 1 , further comprising:
a measurement component configured to measure the implantation angle as the ion beam is swept up and down the workpiece; and
a controller operatively coupled to the measurement component, beam generating component, and mass resolving component, and configured to adjust the operation of at least one of the beam generating component and the mass resolving component in response to measurements taken by the measurement component.
11. A method of implanting ions into a workpiece in an ion implantation system, comprising:
generating an ion beam;
mass resolving the ion beam;
sweeping the ion beam up and/or down along an entirety of the workpiece along a sweeping axis; and
tilting the workpiece along a beam axis synchronously with the sweeping of the ion beam to maintain a substantially constant implantation angle over the workpiece.
12. The method of claim 11 , further comprising:
scanning the ion beam across a scanning axis that is different than the sweeping axis.
13. The method of claim 12 , where the scanning produces a time-averaged scanned pencil ion beam.
14. The method of claim 11 , further comprising:
moving a resolving aperture synchronously with the sweeping of the ribbon beam so that desired ions of the beam pass therethrough, but contaminants are blocked thereby.
15. The method of claim 14 , where moving the resolving aperture comprises moving one or more resolving plates which define the aperture.
16. The method of claim 11 , further comprising:
measuring the implantation angle as the ion beam is swept up and/or down the workpiece, and
utilizing the implantation angle measurement to maintain the substantially constant implantation angle over the workpiece.
17. The method of claim 16 , where the implantation angle measurement is utilized during the tilting of the workpiece along the beam axis.
18. The method of claim 16 , where the implantation angle measurement is utilized during at least one of the generating and the mass resolving of the ion beam.
19. The system of claim 2 , wherein a sweeping direction of the sweeping component and a scanning direction of the scanning component are generally orthogonal to one another, and wherein a sweeping frequency of the sweeping component is less than a scanning frequency of the scanning component.
20. The method of claim 12 , wherein a sweeping direction of sweeping the ion beam and a scanning direction of scanning the ion beam are generally orthogonal to one another, and wherein a sweeping frequency of the sweeping of the ion beam is less than a scanning frequency of the scanning of the ion beam.