Polishing pad with homogeneous body having discrete protrusions thereon

Abstract

Polishing pads with homogeneous bodies having discrete protrusions thereon are described. In an example, a polishing pad for polishing a substrate includes a homogeneous body having a polishing side and a back side. The homogeneous body is composed of a material having a first hardness. A plurality of discrete protrusions is disposed on and covalently bonded with the polishing side of the homogeneous body. The plurality of discrete protrusions is composed of a material having a second hardness different from the first hardness. Methods of fabricating polishing pads with homogeneous bodies having discrete protrusions thereon are also described.

1 . A polishing pad for polishing a substrate, the polishing pad comprising:
 a homogeneous body having a polishing side and a back side, the homogeneous body comprising a material having a first hardness; and   a plurality of discrete protrusions disposed on and covalently bonded with the polishing side of the homogeneous body, the plurality of discrete protrusions comprising a material having a second hardness different from the first hardness.   
     
     
         2 . The polishing pad of  claim 1 , wherein the polishing side of the homogeneous body is substantially flat and is exposed between the plurality of discrete protrusions. 
     
     
         3 . The polishing pad of  claim 1 , wherein the homogeneous body is a molded homogeneous body, and wherein the plurality of discrete protrusions is a plurality of molded protrusions. 
     
     
         4 . The polishing pad of  claim 1 , wherein the material of the homogeneous body comprises a first thermoset polyurethane material, and the material of the plurality of discrete protrusions comprises a second, different, thermoset polyurethane material. 
     
     
         5 . The polishing pad of  claim 1 , wherein the first hardness of the material of the homogeneous body is less than the second hardness of the material of the plurality of discrete protrusions. 
     
     
         6 . The polishing pad of  claim 5 , wherein the first hardness is less than approximately 40 Shore D, and the second hardness is greater than approximately 30 Shore D. 
     
     
         7 . The polishing pad of  claim 6 , wherein the first hardness is less than approximately 25 Shore D, and the second hardness is greater than approximately 40 Shore D. 
     
     
         8 . The polishing pad of  claim 1 , wherein the first hardness of the material of the homogeneous body is greater than the second hardness of the material of the plurality of discrete protrusions. 
     
     
         9 . The polishing pad of  claim 8 , wherein the second hardness is less than approximately 40 Shore D, and the first hardness is greater than approximately 30 Shore D. 
     
     
         10 . The polishing pad of  claim 9 , wherein the second hardness is less than approximately 25 Shore D, and the first hardness is greater than approximately 40 Shore D. 
     
     
         11 . The polishing pad of  claim 1 , wherein the homogeneous body is substantially circular, and one or more of the plurality of discrete protrusions is a partial circumferential protrusion or an arc-shaped protrusion. 
     
     
         12 . The polishing pad of  claim 1 , wherein the plurality of discrete protrusions comprises a plurality of tiles selected from the group consisting of circular tiles, oval tiles, square tiles, hexagonal tiles, and rectangular tiles. 
     
     
         13 . The polishing pad of  claim 1 , wherein each of the plurality of discrete protrusions has, in a global plane of the polishing side of the homogeneous body, a shortest dimension approximately in the range of 5-50 millimeters. 
     
     
         14 . The polishing pad of  claim 1 , further comprising:
 a detection region disposed in the back side of the homogeneous body.   
     
     
         15 . The polishing pad of  claim 1 , further comprising:
 a local area transparency (LAT) region disposed in the homogeneous body.   
     
     
         16 . A polishing pad for polishing a substrate, the polishing pad comprising:
 a homogeneous body having a polishing side and a back side, the homogeneous body comprising a material having a first hardness, and the polishing side comprising a plurality of protrusions having a pattern;   a plurality of discrete protrusions disposed on and aligned with the plurality of protrusions of the polishing side of the homogeneous body, the plurality of discrete protrusions comprising a material having a second hardness different from the first hardness, and the plurality of discrete protrusions having the pattern; and   a fill layer disposed on the homogeneous body, around the plurality of protrusions of the polishing side of the homogeneous body, the fill layer comprising the material of the plurality of discrete protrusions.   
     
     
         17 . The polishing pad of  claim 16 , wherein the fill layer is discontinuous with the plurality of discrete protrusions. 
     
     
         18 . The polishing pad of  claim 16 , wherein both the fill layer and the plurality of discrete protrusions are covalently bonded with the homogeneous body. 
     
     
         19 . The polishing pad of  claim 16 , wherein the homogeneous body is a molded homogeneous body, wherein the plurality of discrete protrusions is a plurality of molded protrusions, and wherein the fill layer is a molded fill layer. 
     
     
         20 . The polishing pad of  claim 16 , wherein the material of the homogeneous body comprises a first thermoset polyurethane material, and the material of the plurality of discrete protrusions and the fill layer comprises a second, different, thermoset polyurethane material. 
     
     
         21 . The polishing pad of  claim 16 , wherein the first hardness of the material of the homogeneous body is less than the second hardness of the material of the plurality of discrete protrusions and the fill layer. 
     
     
         22 . The polishing pad of  claim 21 , wherein the first hardness is less than approximately 40 Shore D, and the second hardness is greater than approximately 30 Shore D. 
     
     
         23 . The polishing pad of  claim 22 , wherein the first hardness is less than approximately 25 Shore D, and the second hardness is greater than approximately 40 Shore D. 
     
     
         24 . The polishing pad of  claim 16 , wherein the first hardness of the material of the homogeneous body is greater than the second hardness of the material of the plurality of discrete protrusions and the fill layer. 
     
     
         25 . The polishing pad of  claim 24 , wherein the second hardness is less than approximately 40 Shore D, and the first hardness is greater than approximately 30 Shore D. 
     
     
         26 . The polishing pad of  claim 25 , wherein the second hardness is less than approximately 25 Shore D, and the first hardness is greater than approximately 40 Shore D. 
     
     
         27 . The polishing pad of  claim 16 , wherein the homogeneous body is substantially circular, and one or more of the plurality of discrete protrusions is a partial circumferential protrusion or an arc-shaped protrusion. 
     
     
         28 . The polishing pad of  claim 16 , wherein the plurality of discrete protrusions comprises a plurality of tiles selected from the group consisting of circular tiles, oval tiles, square tiles, hexagonal tiles, and rectangular tiles. 
     
     
         29 . The polishing pad of  claim 16 , wherein each of the plurality of discrete protrusions has, in a global plane of the polishing side of the homogeneous body, a shortest dimension approximately in the range of 5-50 millimeters. 
     
     
         30 . The polishing pad of  claim 16 , further comprising:
 a detection region disposed in the back side of the homogeneous body.   
     
     
         31 . The polishing pad of  claim 16 , further comprising:
 a local area transparency (LAT) region disposed in the homogeneous body.   
     
     
         32 . A method of fabricating a polishing pad for polishing a substrate, the method comprising:
 mixing a first set of polymerizable materials to form a first mixture in the base of a formation mold;   at least partially curing the first mixture to form a molded homogeneous body having a polishing side and a back side;   mixing a second set of polymerizable materials to form a second mixture on the molded homogeneous body;   placing a lid of the formation mold into the second mixture, the lid having disposed thereon a pattern of grooves; and, with the lid placed in the second mixture,   at least partially curing the second mixture to form a plurality of discrete protrusions disposed on the polishing side of the molded homogeneous body, the plurality of discrete protrusions having a pattern corresponding to the pattern of grooves of the lid.   
     
     
         33 . The method of  claim 32 , further comprising:
 subsequent to mixing the first set of polymerizable materials to form the first mixture but prior to mixing the second set of polymerizable materials to form the second mixture, placing the lid of the formation mold into the first mixture and, with the lid placed in the first mixture, performing the at least partially curing the first mixture to form the molded homogeneous body with the polishing side comprising a plurality of protrusions having a pattern corresponding to the pattern of grooves of the lid, wherein the plurality of discrete protrusions is formed on and aligned with the plurality of protrusions of the polishing side of the molded homogeneous body.   
     
     
         34 . The method of  claim 33 , wherein forming the second mixture on the molded homogeneous body comprises forming an amount of the second mixture sufficiently large to form a fill layer disposed on the molded homogeneous body, around the plurality of protrusions of the polishing side of the molded homogeneous body, and wherein the amount of the second mixture is sufficiently small to form the fill layer discontinuous with the plurality of discrete protrusions formed from the second mixture. 
     
     
         35 . The method of  claim 32 , wherein the first set of polymerizable materials comprises a first pre-polymer and a first curative, and the second set of polymerizable materials comprises a second pre-polymer and a second curative. 
     
     
         36 . The method of  claim 32 , wherein the polishing side of the molded homogeneous body is substantially flat and is exposed between the plurality of discrete protrusions. 
     
     
         37 . The method of  claim 32 , wherein the second mixture is different from the first mixture, and wherein, upon fully curing the first and second mixtures, the hardness of the plurality of discrete protrusions is different from the hardness of the molded homogeneous body. 
     
     
         38 . The method of  claim 32 , wherein at least partially curing the second mixture comprises covalently boding the plurality of discrete protrusions with the molded homogeneous body. 
     
     
         39 . The method of  claim 32 , wherein forming the molded homogeneous body comprises forming a first thermoset polyurethane material, and forming the plurality of discrete protrusions comprises forming a second, different, thermoset polyurethane material. 
     
     
         40 . The method of  claim 32 , wherein the mixing of the second set of polymerizable materials further comprises adding a plurality of porogens to the second set of polymerizable materials to form a plurality of closed cell pores in the plurality of discrete protrusions, each closed cell pore having a physical shell. 
     
     
         41 . The method of  claim 32 , wherein the mixing of the second set of polymerizable materials further comprises injecting a gas into the second set of polymerizable materials, or into a product formed there from, to form a plurality of closed cell pores in the plurality of discrete protrusions, each closed cell pore having no physical shell. 
     
     
         42 . The method of  claim 32 , wherein the mixing of the second set of polymerizable materials further comprises adding an opacifying particle filler to the second set of polymerizable materials to form an opaque plurality of discrete protrusions. 
     
     
         43 . The method of  claim 32 , further comprising:
 further curing the plurality of discrete protrusions and the molded homogeneous body in an oven.   
     
     
         44 . The method of  claim 35 , wherein mixing the first pre-polymer and the first curative to form the first mixture comprises degassing the first mixture, and wherein mixing the second pre-polymer and the second curative to form the second mixture comprises degassing the second mixture.