Polishing pad with multi-modal distribution of pore diameters
View Patent ↗Polishing pads with multi-modal distributions of pore diameters are described. Methods of fabricating polishing pads with multi-modal distributions of pore diameters are also described.
1. A polishing pad for polishing a semiconductor substrate, the polishing pad comprising:
a homogeneous polishing body having a first, grooved surface and a second, flat surface opposite the first surface, the homogeneous polishing body comprising:
a thermoset polyurethane material; and
a plurality of closed cell pores disposed in the thermoset polyurethane material, the plurality of closed cell pores having a multi-modal distribution of diameters, wherein the multi-modal distribution of diameters is graded throughout the thermoset polyurethane material with a gradient from the first, grooved surface to the second, flat surface.
2. The polishing pad of claim 1 , wherein each of the closed cell pores comprises a physical shell.
3. The polishing pad of claim 1 , wherein the multi-modal distribution of diameters is a bimodal distribution of diameters comprising a small diameter mode and a large diameter mode.
4. The polishing pad of claim 3 , wherein the diameter value for the maximum population of the large diameter mode is approximately twice the diameter value of the maximum population of the small diameter mode.
5. The polishing pad of claim 4 , wherein the diameter value for the maximum population of the large diameter mode is approximately 40 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
6. The polishing pad of claim 4 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, and the diameter value of the maximum population of the small diameter mode is approximately 40 microns.
7. The polishing pad of claim 3 , wherein the diameter value for the maximum population of the large diameter mode is approximately four times greater than the diameter value of the maximum population of the small diameter mode.
8. The polishing pad of claim 7 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
9. The polishing pad of claim 3 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode is suitable to provide a polishing surface of the polishing pad with highly uniform polishing slurry distribution, and the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide reservoirs for storing polishing slurry for use with the closed cell pores of the small diameter mode.
10. The polishing pad of claim 3 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode is suitable to provide a polishing surface of the polishing pad with highly uniform polishing slurry distribution, and the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide locations for receiving a diamond tip during conditioning of the polishing pad.
11. The polishing pad of claim 3 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode provides an insufficient heat sink during a polishing process, the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide an excessive heat sink during a polishing process, and the combination of the closed cell pores of the small diameter mode and the closed cell pores of the large diameter mode is suitable to provide thermal stability during the polishing process.
12. The polishing pad of claim 3 , wherein the population of the large diameter mode overlaps with the population of the small diameter mode.
13. The polishing pad of claim 3 , wherein the population of the large diameter mode has essentially no overlap with the population of the small diameter mode.
14. The polishing pad of claim 3 , wherein the total population of the large diameter mode is not equal to the total population of the small diameter mode.
15. The polishing pad of claim 3 , wherein the total population of the large diameter mode is approximately equal to the total population of the small diameter mode.
16. The polishing pad of claim 1 , wherein the multi-modal distribution of diameters is a trimodal distribution of diameters comprising a small diameter mode, a medium diameter mode, and a large diameter mode.
17. The polishing pad of claim 16 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, the diameter value of the maximum population of the medium diameter mode is approximately 40 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
18. The polishing pad of claim 1 , wherein the multi-modal distribution of diameters is a bimodal distribution of diameters comprising a small diameter mode proximate to the first, grooved surface, and comprising a large diameter mode proximate to the second, flat surface.
19. The polishing pad of claim 1 , wherein the homogeneous polishing body is a molded homogeneous polishing body.
20. The polishing pad of claim 1 , wherein the homogeneous polishing body further comprises:
an opacifying lubricant distributed approximately evenly throughout the homogeneous polishing body.
21. The polishing pad of claim 1 , further comprising:
a local area transparency (LAT) region disposed in, and covalently bonded with, the homogeneous polishing body.
22. A polishing pad for polishing a semiconductor substrate, the polishing pad comprising:
a homogeneous polishing body comprising:
a thermoset polyurethane material; and
a plurality of closed cell pores disposed in the thermoset polyurethane material, the plurality of closed cell pores having a multi-modal distribution of diameters, wherein each of the plurality of closed cell pores comprises a physical shell.
23. The polishing pad of claim 22 , wherein the multi-modal distribution of diameters is a bimodal distribution of diameters comprising a small diameter mode and a large diameter mode.
24. The polishing pad of claim 23 , wherein the diameter value for the maximum population of the large diameter mode is approximately twice the diameter value of the maximum population of the small diameter mode.
25. The polishing pad of claim 24 , wherein the diameter value for the maximum population of the large diameter mode is approximately 40 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
26. The polishing pad of claim 24 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, and the diameter value of the maximum population of the small diameter mode is approximately 40 microns.
27. The polishing pad of claim 23 , wherein the diameter value for the maximum population of the large diameter mode is approximately four times greater than the diameter value of the maximum population of the small diameter mode.
28. The polishing pad of claim 27 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
29. The polishing pad of claim 23 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode is suitable to provide a polishing surface of the polishing pad with highly uniform polishing slurry distribution, and the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide reservoirs for storing polishing slurry for use with the closed cell pores of the small diameter mode.
30. The polishing pad of claim 23 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode is suitable to provide a polishing surface of the polishing pad with highly uniform polishing slurry distribution, and the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide locations for receiving a diamond tip during conditioning of the polishing pad.
31. The polishing pad of claim 23 , wherein the diameter of the maximum population of the closed cell pores of the small diameter mode provides an insufficient heat sink during a polishing process, the diameter of the maximum population of the closed cell pores of the large diameter mode is suitable to provide an excessive heat sink during a polishing process, and the combination of the closed cell pores of the small diameter mode and the closed cell pores of the large diameter mode is suitable to provide thermal stability during the polishing process.
32. The polishing pad of claim 23 , wherein the population of the large diameter mode overlaps with the population of the small diameter mode.
33. The polishing pad of claim 23 , wherein the population of the large diameter mode has essentially no overlap with the population of the small diameter mode.
34. The polishing pad of claim 23 , wherein the total population of the large diameter mode is not equal to the total population of the small diameter mode.
35. The polishing pad of claim 23 , wherein the total population of the large diameter mode is approximately equal to the total population of the small diameter mode.
36. The polishing pad of claim 22 , wherein the multi-modal distribution of diameters is a trimodal distribution of diameters comprising a small diameter mode, a medium diameter mode, and a large diameter mode.
37. The polishing pad of claim 36 , wherein the diameter value for the maximum population of the large diameter mode is approximately 80 microns, the diameter value of the maximum population of the medium diameter mode is approximately 40 microns, and the diameter value of the maximum population of the small diameter mode is approximately 20 microns.
38. The polishing pad of claim 22 , wherein the multi-modal distribution of diameters is distributed essentially evenly throughout the thermoset polyurethane material.
39. The polishing pad of claim 22 , wherein the homogeneous polishing body further comprises:
a first, grooved surface; and
a second, flat surface opposite the first surface, wherein the multi-modal distribution of diameters is graded throughout the thermoset polyurethane material with a gradient from the first, grooved surface to the second, flat surface, wherein the multi-modal distribution of diameters is a bimodal distribution of diameters comprising a small diameter mode proximate to the first, grooved surface, and comprising a large diameter mode proximate to the second, flat surface.
40. The polishing pad of claim 22 , wherein the homogeneous polishing body is a molded homogeneous polishing body.
41. The polishing pad of claim 22 , wherein the homogeneous polishing body further comprises:
an opacifying lubricant distributed approximately evenly throughout the homogeneous polishing body.
42. The polishing pad of claim 22 , further comprising:
a local area transparency (LAT) region disposed in, and covalently bonded with, the homogeneous polishing body.