Apparatus and method to electrostatically remove foreign matter from substrate surfaces
In one exemplary embodiment, described herein are innovative techniques for reducing the attractive force between particles and a substrate surface to aid in the removal of particles from the substrate surface. More specifically, a multi-electrode chuck is utilized to assist in cleaning a substrate. The multi-electrode chuck is utilized to reduce the attractive forces between particles and the substrate and to move the loosened particles that are present on the substrate surface. The electrodes of the chuck are biased with alternating current (AC) voltages with a phase shift between the electrode bias waves. The resulting electric field wave on the substrate surface loosens the particles by polarizing the particles and moves the loosened particles across the substrate.
1. A method of removing particles from a surface of a substrate in a substrate processing tool, the method comprising:
applying a plurality of phase shifted alternating voltages to a plurality of electrodes, the plurality of electrodes disposed within a chuck of the substrate processing tool, each of the plurality of electrodes separated by one of a plurality of spacings, a width of an electrode of the plurality of electrodes and a width of one of the plurality of spacings are each sized to be within 20% of a distance between a top of the plurality of electrodes and the surface of the substrate, the phase shifted alternating voltages being coupled to the plurality of electrodes in a pattern such that adjacent electrodes have voltages that are phase shifted; and
generating an electric potential at a surface of the substrate by applying the plurality of phase shifted alternating voltages to the plurality of electrodes when the substrate is placed over the chuck, the generating removing the
particles from the surface by moving the particles across the surface of the substrate.
2. The method of claim 1 , wherein the plurality of phase shifted alternating voltages comprises at least three phase shifted voltages.
3. The method of claim 1 , wherein the plurality of phase shifted alternating voltages comprises three phase shifted voltages having phase shifts of 120 degrees.
4. The method of claim 1 , wherein the electric potential at the surface of the substrate alternates across the substrate due to phase shifts in the plurality of phase shifted alternating voltages.
5. The method of claim 1 , wherein the width of the electrode of the plurality of electrodes and the width of one of the plurality of spacings are sized to be within 5% of the distance between the top of the plurality of electrodes and the surface of the substrate.
6. The method of claim 5 , wherein the plurality of phase shifted alternating voltages comprises three phase shifted voltages having phase shifts of 120 degrees.
7. A method of removing particles from a surface of a semiconductor wafer in a semiconductor processing tool, the method comprising:
providing a chuck for holding the semiconductor wafer within the semiconductor processing tool;
providing a plurality of electrodes within the chuck, the plurality of electrodes is embedded in a dielectric material such that each electrode is separated from an adjacent one of the plurality of electrodes only by a region of the dielectric material, wherein a width of one of the plurality of electrodes and a width of the region of the dielectric material are about equal;
providing at least three phase shifted alternating voltages to the plurality of electrodes, the at least three phase shifted alternating voltages being coupled to the plurality of electrodes in a pattern such that adjacent electrodes have voltages that are phase shifted; and
generating an electric potential at a surface of the semiconductor wafer by applying the at least three phase shifted alternating voltages to the plurality of electrodes when the semiconductor wafer is placed over the chuck, the generating removing the particles from the surface by moving the particles across the surface of the semiconductor wafer, wherein the electric potential at the surface of the semiconductor wafer alternates across the semiconductor wafer due to phase shifts in the at least three phase shifted alternating voltages.
8. The method of claim 7 , wherein the at least three phase shifted alternating voltages comprises three phase shifted voltages having phase shifts of 120 degrees.
9. The method of claim 8 , wherein at least one geometric characteristic of the plurality of electrodes is dependent upon a height of the semiconductor wafer.
10. The method of claim 7 , wherein the width of one of the plurality of electrodes and the width of the region of the dielectric material are each sized to be within 20% of a distance between a top of the plurality of electrodes and the surface of the semiconductor wafer.
11. The method of claim 1 , further comprising performing a wet process to assist removing the particles from the surface.
12. The method of claim 1 , further comprising blowing air jets across the substrate to assist removing the particles from the surface.
13. The method of claim 1 , wherein the plurality of electrodes is embedded in a dielectric material such that each electrode is separated from an adjacent one of the plurality of electrodes only by a region of the dielectric material.
14. The method of claim 7 , wherein the at least three phase shifted alternating voltages are applied at a frequency of 1 Hz to 500 kHz and in a range from 2000 V to 8000 V.
15. A method of removing particles from a surface of a substrate in a plasmas processing tool, the method comprising:
loading the substrate over a chuck within the plasma processing tool, the chuck comprising a plurality of electrodes embedded in a dielectric material, adjacent electrodes of the plurality of electrodes being separated only by a region of the dielectric material, wherein a width of one of the plurality of electrodes and a width of the region of the dielectric material are about equal;
powering a plasma for a plasma processing of the substrate; and
while powering the plasma, powering the plurality of electrodes with phase shifted alternating voltages so that each electrode is coupled to one of the phase shifted alternating voltages to generate a voltage wave moving across the surface of the substrate, the voltage wave causing particles to move across the surface and be removed from the surface.
16. The method of claim 15 , wherein the width of the region of the dielectric material or the width of one of the plurality of electrodes is within a range between 0.3 mm to 3 mm.
17. The method of claim 15 , wherein the width of an electrode one of the plurality of electrodes and the width of the region of the dielectric material are each sized to be within 20% of a distance between a top of the plurality of electrodes and the surface of the substrate.
18. The method of claim 15 , wherein the width of one of the plurality of electrodes and the width of the region of the dielectric material are each sized to be within 5% of a distance between a top of the plurality of electrodes and the surface of the substrate.
19. The method of claim 15 , wherein the width of one of the plurality of electrodes, the width of the region of the dielectric material between the electrodes, and a distance between a top of the plurality of electrodes and the surface of the substrate are about equal.
20. The method of claim 15 , further comprising performing an assisting process to assist removing the particles from the surface.