POLISHING PAD WITH FOUNDATION LAYER AND POLISHING SURFACE LAYER
Polishing pads with foundation layers and polishing surface layers are described. In an example, a polishing pad for polishing a substrate includes a foundation layer. A polishing surface layer is bonded to the foundation layer. Methods of fabricating polishing pads with a polishing surface layer bonded to a foundation layer are also described.
1 . A polishing pad for polishing a substrate, the polishing pad comprising:
a foundation layer having a first hardness;
a polishing surface layer bonded directly to the foundation layer, the polishing surface layer having a second hardness less than the first hardness; and
an aperture disposed in the polishing pad, through the polishing surface layer and the foundation layer.
2 . The polishing pad of claim 1 , wherein the polishing surface layer comprises a continuous layer portion with a plurality of polishing features protruding there from, the continuous layer portion bonded directly to the foundation layer.
3 . The polishing pad of claim 1 , wherein the polishing surface layer comprises a plurality of discrete polishing protrusions bonded directly to the foundation layer.
4 . The polishing pad of claim 1 , wherein the polishing surface layer is covalently bonded to the foundation layer.
5 . The polishing pad of claim 1 , wherein the foundation layer and the polishing surface layer have a peel resistance sufficient to withstand a shear force applied during the useful lifetime of the polishing pad.
6 . The polishing pad of claim 1 , wherein the foundation layer has a surface roughness greater than approximately 1 micrometer Ra (root mean square) where the polishing surface layer is bonded directly to the foundation layer.
7 . The polishing pad of claim 6 , wherein the surface roughness is approximately in the range of 5-10 micrometers Ra (root mean square).
8 . The polishing pad of claim 1 , wherein the foundation layer has a smooth surface with a surface roughness less than approximately 1 micrometer Ra (root mean square) where the polishing surface layer is bonded directly to the foundation layer.
9 . The polishing pad of claim 8 , wherein the polishing surface layer comprises a material formed from polyurethane.
10 . The polishing pad of claim 1 , wherein the foundation layer has an energy loss factor of less than approximately 100 KEL at 1/Pa at 40° C.
11 . The polishing pad of claim 1 , wherein the foundation layer has a compressibility of less than approximately 1% under a central pressure of 5 PSI.
12 . The polishing pad of claim 1 , wherein the foundation layer has a hardness greater than approximately 75 Shore D.
13 . The polishing pad of claim 1 , wherein the foundation layer comprises a polycarbonate material.
14 . The polishing pad of claim 1 , wherein the foundation layer comprises a material selected from the group consisting of an epoxy board material and a metal sheet.
15 . The polishing pad of claim 1 , wherein the polishing surface layer has an energy loss factor of greater than approximately 1000 KEL at 1/Pa at 40° C.
16 . The polishing pad of claim 1 , wherein the polishing surface layer has a compressibility of greater than approximately 0.1% under a central pressure of 5 PSI.
17 . The polishing pad of claim 1 , wherein the polishing surface layer has a hardness less than approximately 70 Shore D.
18 . The polishing pad of claim 1 , wherein the polishing surface layer is a homogeneous polishing surface layer.
19 . The polishing pad of claim 18 , wherein the homogeneous polishing surface layer comprises a thermoset polyurethane material.
20 . The polishing pad of claim 1 , wherein the polishing surface layer has a pore density of closed cell pores approximately in the range of 6% - 50% total void volume.
21 . The polishing pad of claim 1 , wherein the foundation layer has an energy loss factor of less than approximately 100 KEL at 1/Pa at 40° C., wherein the polishing surface layer has an energy loss factor of greater than approximately 1000 KEL at 1/Pa at 40° C., and wherein the foundation layer and the polishing surface layer together have an energy loss factor of less than approximately 100 KEL at 1/Pa at 40° C.
22 . The polishing pad of claim 1 , wherein the foundation layer has a hardness approximately in the range of 70-90 Shore D, and the polishing surface layer has a hardness approximately in the range of 50-60 Shore D.
23 . The polishing pad of claim 1 , wherein the foundation layer has a hardness approximately in the range of 70-90 Shore D, and the polishing surface layer has a hardness approximately in the range of 20-50 Shore D.
24 . The polishing pad of claim 1 , wherein the polishing surface layer has a first modulus of elasticity, and the foundation layer has a second modulus of elasticity greater than approximately 10 times the first modulus of elasticity.
25 . The polishing pad of claim 24 , wherein the polishing surface layer has a first modulus of elasticity, and the foundation layer has a second modulus of elasticity greater than approximately 100 times the first modulus of elasticity.
26 . The polishing pad of claim 1 , wherein the polishing surface layer has a thickness approximately in the range of 2-50 mils, and the foundation layer has a thickness of greater than approximately 20 mils.
27 . The polishing pad of claim 26 , wherein the thickness of the foundation layer is greater than the thickness of the polishing surface layer.
28 . The polishing pad of claim 1 , wherein the foundation layer has a thickness and hardness relative to the thickness and hardness of the polishing surface layer sufficient to dictate the bulk polishing characteristics of the polishing pad.
29 . The polishing pad of claim 1 , wherein the foundation layer is sufficiently thick for the polishing pad to provide die-level polishing planarity, but sufficiently thin for the polishing pad to provide wafer-level polishing uniformity.
30 . The polishing pad of claim 1 , further comprising:
a detection region disposed in the foundation layer.
31 . The polishing pad of claim 1 , further comprising:
an adhesive sheet disposed on a back surface of the foundation layer but not in the aperture, the adhesive sheet providing an impermeable seal for the aperture at the back surface of the foundation layer.
32 . The polishing pad of claim 1 , further comprising:
a sub pad having a third hardness less than the first hardness, wherein the foundation layer is disposed proximate to the sub pad.
33 . The polishing pad of claim 32 , wherein the foundation layer has a hardness approximately in the range of 70-90 Shore D, the polishing surface layer has a hardness approximately in the range of 20-60 Shore D, and the sub pad has a hardness less than approximately 90 Shore A.
34 . The polishing pad of claim 32 , wherein the polishing pad provides die-level polishing planarity and wafer-level polishing uniformity.
35 . The polishing pad of claim 1 , wherein the foundation layer comprises a stack of sub layers.