Pixelated capacitance controlled ESC
Implementations described herein provide a pixilated electrostatic chuck which enables both lateral and azimuthal tuning of the RF coupling between an electrostatic chuck and a substrate placed thereon. In one embodiment, the pixilated electrostatic chuck (ESC) may include a dielectric body having a workpiece support surface configured to accept a substrate thereon, one or more chucking electrodes disposed in the pixilated ESC, and a plurality of pixel electrodes. The plurality of pixel electrodes are switchable between a floating state and a grounded state, having variable capacitance to ground, or both. The pixel electrodes and the chucking electrodes form a circuit operable to electrostatically chuck the substrate to the workpiece support surface.
1. A pixilated electrostatic chuck (ESC), comprising:
a dielectric body having a workpiece support surface configured to accept a substrate thereon;
one or more chucking electrodes disposed in the pixilated ESC; and
a plurality of pixel electrodes switchable between a floating state and a grounded state, having variable capacitance to ground, or both, the pixel electrodes and chucking electrodes forming a circuit operable to electrostatically chuck the substrate to the workpiece support surface.
2. The pixilated ESC of claim 1 further comprising:
a bank of capacitors coupled between the pixel electrodes and ground.
3. The pixilated ESC of claim 1 , wherein at least one of the capacitors is a MEMS capacitor.
4. The pixilated ESC of claim 3 , wherein the capacitors are about 3.2 mm×3.2 mm×0.53 mm or smaller.
5. The pixilated ESC of claim 1 , wherein chucking electrodes are arranged in a grid.
6. The pixilated ESC of claim 1 , wherein the capacitors are integrated into the body.
7. The pixilated ESC of claim 1 , wherein the pixel capacitors are RF variable capacitors.
8. The pixilated ESC of claim 1 , wherein the capacitors have a capacitance uniformity across the body that is less than about 10%.
9. The pixilated ESC of claim 1 , wherein capacitors are disposed in the pixilated ESC.
10. The pixilated ESC of claim 1 , wherein the capacitance between at least one of the pixel electrode and ground is about 20 pF.
11. A processing chamber comprising:
chamber body;
a pixilated electrostatic chuck (ESC) disposed in the chamber body, the pixilated ESC comprising:
a dielectric body having a workpiece support surface configured to accept a substrate thereon;
one or more chucking electrodes disposed in the pixilated ESC; and
a plurality of pixel electrodes switchable between a floating state and a grounded state, having variable capacitance to ground, or both, the pixel electrodes and chucking electrodes forming a circuit operable to electrostatically chuck the substrate to the workpiece support surface.
12. The processing chamber of claim 11 further comprising:
a bank of capacitors coupled between the pixel electrodes and ground.
13. The processing chamber of claim 11 , wherein at least one of the capacitors is a MEMS capacitor.
14. The pixilated ESC of claim 11 , wherein the processing chamber is an etch chamber, a deposition chamber, or an ion implant chamber.
15. The processing chamber of claim 11 , wherein chucking electrodes are arranged in a grid.
16. The processing chamber of claim 11 , wherein the pixel capacitors are RF variable capacitors.
17. A method for processing a substrate, comprising:
applying power to a main chucking electrode formed in a pixilated electrostatic chuck;
selectively coupling one or more of a plurality of pixel electrodes distributed laterally within the pixilated electrostatic chuck to ground to secure a substrate to the pixilated electrostatic chuck; and
processing the substrate on the pixilated electrostatic chuck.
18. The method of claim 17 , further comprising:
controlling at least one of a duration and duty cycle of the coupling of each pixel electrode to ground relative to the other pixel electrodes disposed within pixilated electrostatic chuck.
19. The method of claim 17 , further comprising:
controlling a capacitance between at least one pixel electrode and ground relative to the other pixel electrodes disposed within pixilated electrostatic chuck.
20. The method of claim 17 , further comprising:
changing a coupling between one or more of the plurality of pixel electrodes distributed laterally within the pixilated electrostatic chuck and ground in response to a change in a process condition or a change in a process recipe.