Polishing pad, a polishing apparatus, and a process for using the polishing pad
View Patent ↗A polishing pad can include a first layer and a second layer. The first layer can have a first polishing surface and a first opening. The second layer can have an attaching surface and a second opening substantially contiguous with the first opening. The polishing pad can further include a pad window lying within the first opening. The pad window can include a second polishing surface and a gas-permeable material. In one aspect, an apparatus can include an attaching surface of a platen lying adjacent to the attaching surface of the polishing pad. In another aspect, a process for polishing can include changing a temperature of a gas within a spaced-apart region formed between a pad and a platen. The process can also include forming a gas flux across the polishing pad after polishing has started.
1. A polishing pad comprising:
a first layer comprising:
a first polishing surface;
a first opposing surface opposite the first polishing surface; and
a first opening extending through the first layer;
a second layer comprising:
an attaching surface;
a second opposing surface opposite the attaching surface, and lying closer to the first opposing surface of the first layer than to the first polishing surface of the first layer; and
a second opening extending through the second layer, the second opening substantially contiguous with the first opening of the first layer; and
a pad window lying within the first opening and comprising:
a second polishing surface substantially contiguous with the first polishing surface; and
a third opposing surface opposite the second polishing surface, wherein the third opposing surface lies in a region between the first polishing surface of the first layer and the attaching surface of the second layer, and the pad window comprises a gas-permeable material.
2. The polishing pad of claim 1 , wherein the pad window comprises a composition that is capable of allowing transmission of a predetermined wavelength or spectrum of radiation.
3. The polishing pad of claim 1 , wherein the first layer and the pad window each comprise a urethane a polyethylene, a polytetrafluoroethylene, a polypropylene, or any combination thereof.
4. The polishing pad of claim 1 , wherein the first opposing surface of the first layer lies adjacent to the second opposing surface of the second layer.
5. The polishing pad of claim 1 , wherein a first perimeter of the first opening has a different length than a second perimeter of the second opening.
6. The polishing pad of claim 1 , wherein:
the first polishing surface of the first layer and the second polishing surface of the pad window lie substantially along a polishing plane; and
a first elevation from the third opposing surface of the pad window to the polishing plane is less than a second elevation from the attaching surface to the polishing plane.
7. The polishing pad of claim 6 , wherein the first elevation is less than a third elevation from the first opposing surface of the first layer to the polishing plane.
8. A polishing apparatus comprising:
a platen comprising a first attaching surface; and
a polishing pad comprising:
a first layer overlying and spaced-apart from the platen, wherein the first layer comprises:
a first polishing surface;
a first opposing surface opposite the first polishing surface; and
a first opening extending through the first layer;
a second layer lying between the first layer and the platen, wherein the second layer comprises:
a second attaching surface lying adjacent to the first attaching surface of the platen;
a second opposing surface opposite the second attaching surface, and lying closer to the first opposing surface of the first layer than to the first polishing surface of the first layer; and
a second opening extending through the second layer, the second opening substantially contiguous with the first opening of the first layer; and
a pad window lying within the first opening of the first layer and comprising:
a second polishing surface substantially contiguous with the first polishing surface of the first layer; and
a third opposing surface opposite the second polishing surface, and the pad window comprises a gas-permeable material.
9. The polishing apparatus of claim 8 , wherein:
the platen further comprises a platen window;
the pad window overlies the platen window; and
the apparatus further comprises a radiation source configured to direct a predetermined wavelength or spectrum of radiation through the second polishing surface of the pad window.
10. The polishing apparatus of claim 9 , wherein each of the platen window and the pad window is capable of allowing transmission of the predetermined wavelength or spectrum of radiation.
11. The polishing apparatus of claim 8 , wherein a spaced-apart region lies between the third opposing surface of the pad window and the platen.
12. The polishing apparatus of claim 11 , wherein the spaced-apart region comprises air, argon, nitrogen, oxygen, carbon dioxide, or any combination thereof.
13. The polishing apparatus of claim 8 , wherein the first opposing surface of the first layer lies immediately adjacent to the second opposing surface of the second layer.
14. The polishing apparatus of claim 8 , wherein the first polishing surface of the first layer and the second polishing surface of the pad window lie along a same plane.
15. The polishing apparatus of claim 14 , wherein the third opposing surface lies farther from the same plane than from a plane along the second attaching surface of the second layer.
16. The polishing apparatus of claim 8 , wherein a composition of the pad window comprises a urethane, a polyethylene, a polytetrafluoroethylene, a polypropylene, or any combination thereof.
17. A process of polishing comprising:
forming a spaced-apart region between a polishing pad and a platen, wherein the spaced-apart region comprises a gas, and the gas has a first averaged temperature;
polishing a workpiece, wherein at a point in time during polishing, the spaced-apart region lies between the platen and the workpiece;
changing a temperature of the gas within the spaced-apart region from the first averaged temperature to a second averaged temperature after polishing the workpiece has started; and
forming a gas flux across the polishing pad after polishing the workpiece has started.
18. The process of claim 17 , further comprising applying a fluid to a polishing surface of the polishing pad wherein the polishing surface overlies the spaced-apart region and the spaced-apart region remains substantially dry.
19. The process of claim 17 , wherein:
the platen further comprises a platen window; and
the pad further comprises a pad window; and
the spaced-apart region lies between the platen window and the pad window.
20. The process of claim 19 , further comprising:
directing a radiation beam at the workpiece such that the radiation beam passes through a polishing surface of the polishing pad;
detecting a predetermined wavelength or spectrum of radiation from the radiation beam;
analyzing the radiation beam after detecting the predetermined wavelength or spectrum of radiation; and
determining whether an endpoint has been reached.