Chemical mechanical polishing apparatus and method
A polishing platform of a polishing apparatus includes a platen, a polishing pad, and an electric field element disposed between the platen and the polishing pad. The polishing apparatus further includes a controller configured to apply voltages to the electric field element. A first voltage is applied to the electric field element to attract charged particles of a polishing slurry toward the polishing pad. The attracted particles reduce overall topographic variation of a polishing surface presented to a workpiece for polishing. A second voltage is applied to the electric field element to attract additional charged particles of the polishing slurry toward the polishing pad. The additional attracted particles further reduce overall topographic variation of the polishing surface presented to the workpiece. A third voltage is applied to the electric field element to repel charged particles of the polishing slurry away from the polishing pad for improved cleaning thereof.
1. A method of manufacturing a semiconductor device, the method comprising:
distributing a chemical mechanical polishing slurry onto a platen; and
applying a first voltage to an electric field element while the chemical mechanical polishing slurry is present on the platen, wherein the applying the first voltage electrostatically attracts oppositely charged abrasive particles within the chemical mechanical polishing slurry towards the platen;
applying a second voltage to the electric field element while the chemical mechanical polishing slurry is present on the platen, the second voltage being different from the first voltage;
removing the second voltage;
after the removing the second voltage, waiting; and
after the waiting, applying a third voltage to the electric field element.
2. The method of claim 1 , wherein the applying the third voltage repels the abrasive particles away from the platen.
3. The method of claim 2 , further comprising applying a cleaning solution during the applying the third voltage.
4. The method of claim 1 , wherein the first voltage is between 10 mV and 50 V.
5. The method of claim 4 , wherein the second voltage is between 50 V and 100 V.
6. The method of claim 1 , wherein the electric field element is a plate.
7. The method of claim 1 , wherein the electric field element is a mesh.
8. A method of manufacturing a semiconductor device, the method comprising:
applying a chemical mechanical polishing slurry to a platen;
attracting a first monolayer of abrasives within the slurry to the platen with a first voltage;
attracting a second monolayer of abrasives within the slurry to the platen with a second voltage different from the first voltage;
removing the second voltage;
waiting a first period of time after the removing the second voltage; and
after the waiting the first period of time, applying a third voltage.
9. The method of claim 8 , wherein the attracting the first monolayer of abrasives is performed by applying the first voltage to a plate.
10. The method of claim 9 , further comprising repelling the first monolayer of abrasives with the third voltage.
11. The method of claim 8 , wherein the first monolayer of abrasives comprises aluminum oxide.
12. The method of claim 8 , wherein the first monolayer of abrasives comprises silicon oxide.
13. The method of claim 8 , wherein the first voltage is between 10 mV and 50 V.
14. The method of claim 8 , wherein the second voltage is between 50 V and 100 V.
15. A method of manufacturing a semiconductor device, the method comprising:
applying a first voltage with a first polarity to an electric field element adjacent to a polishing pad;
applying a second voltage with the first polarity to the electric field element, the second voltage being different from the first voltage;
applying a third voltage with a second polarity opposite the first polarity to the electric field element;
removing the second voltage from the electric field element prior to the applying the third voltage; and
waiting a first period of time after the removing the second voltage and the applying the third voltage.
16. The method of claim 15 , further comprising dispensing a cleaning solution during the applying the third voltage.
17. The method of claim 15 , further comprising dispensing a chemical mechanical polishing slurry during the applying the first voltage.
18. The method of claim 15 , wherein the first voltage is between 10 mV and 50 V.
19. The method of claim 15 , wherein the second voltage is between 50 V and 100 V.
20. The method of claim 15 , wherein the third voltage has opposite polarity to both the first voltage and the second voltage.