Dose uniformity correction technique
Non uniform ion implantations in a pendulum type of ion implantation are mitigated by adjusting movement of a wafer according to a corresponding non uniform function. More particularly, a non uniform ion implantation function is obtained by measuring and/or modeling ion implantations. Then, movement of a wafer along a second non arcuate scan path is adjusted according to the non uniform ion implantation function to facilitate uniform ion implantations.
1. A method of mitigating non uniform ion implantation in a semiconductor workpiece in a pendulum type of ion implantation, comprising:
oscillating the workpiece in front of an ion beam along a first arcuate scan path; and
moving the workpiece along a second scan path according to a predetermined second scan path rate; and
dynamically adjusting the predetermined second scan path rate according to non uniform ion implantation data.
2. The method of claim 1 , where dynamic adjustment to the movement of the workpiece along the second scan path is a function of the non uniform ion implantation.
3. The method of claim 2 , further comprising:
dividing an original command for moving the workpiece along the second scan path by a function corresponding to the non uniform ion implantation to adjust the movement of the workpiece along the second scan path.
4. The method of claim 3 , where comprising determining the function corresponding to the non uniform ion implantation comprising:
implementing a curve fitting technique.
5. The method of claim 4 , where determining the function corresponding to the non uniform ion implantation comprises:
generating a plot of ion dose across the workpiece.
6. The method of claim 2 , comprising determining the non uniform ion implantation comprising:
substituting a measuring component for the workpiece.
7. The method of claim 6 , where determining the non uniform ion implantation comprises:
modeling ion implantation.
8. The method of claim 7 , where ion implantation is modeled based upon at least one of
orientation of the workpiece to the beam,
angular velocity of the workpiece,
photoresist out gassing,
changes in beam current,
changes in pressure, and
errors in the movement along the first arcuate scan path.
9. A method of mitigating non uniform ion implantation in a semiconductor workpiece in a pendulum type of ion implantation, comprising:
obtaining ion implantation data;
utilizing the ion implantation data to determine a function corresponding to non uniform ion implantation data; and
controlling movement of the workpiece through an ion beam comprising:
moving the workpiece along a first arcuate scan path and moving the workpiece along a second non arcuate scan path according to a predetermined second scan path rate; and
dynamically adjusting the predetermined second scan path rate according to the function corresponding to non uniform ion implantation data, where the movement along the second scan path is adjusted by dividing an original command for moving the workpiece along the second scan path by the function corresponding to non uniform ion implantation.
10. The method of claim 9 , where determining the function corresponding to non uniform ion implantation comprises:
implementing a curve fitting technique.
11. The method of claim 9 , where determining the function corresponding to non uniform ion implantation comprises:
generating a plot of ion dose across the workpiece.
12. The method of claim 11 , were determining the function corresponding to non uniform ion implantation further comprises:
implementing a curve fitting technique.
13. The method of claim 9 , where obtaining ion implantation data comprises:
substituting a measuring component for the workpiece.
14. The method of claim 9 , where the ion implantation data is obtained via modeling.
15. The method of claim 14 , where the modeling considers at least one of
orientation of the workpiece to the beam,
angular velocity of the workpiece,
photoresist out gassing,
changes in beam current,
changes in pressure, and
errors in the movement along the first arcuate scan path.
16. The method of claim 9 , where the function is based on an angle θ′ through which the workpiece is scanned as it moves along the first arcuate scan path.
17. The method of claim 16 , where the function corresponds to cos(θ′).