Sintered polishing pad with regions of contrasting density

Abstract

The invention provides a polishing pad comprising sintered particles of a thermoplastic resin, wherein a surface of the polishing pad intended to contact a substrate to be polished comprises (a) a non-patterned portion with a substantially uniform density and (b) a patterned portion with one or more densities that differ from the density of the non-patterned portion. The invention also provides a method for producing the polishing pad, a chemical-mechanical polishing apparatus comprising the polishing pad, and a method of polishing comprising contacting a substrate with the polishing pad.

What is claimed is:  
     
         1 . A polishing pad comprising sintered particles of a thermoplastic resin, wherein a surface of the polishing pad intended to contact a substrate to be polished comprises a non-patterned portion with a substantially uniform density and a patterned portion with one or more densities that differ from the density of the non-patterned portion.  
     
     
         2 . The polishing pad of  claim 1 , wherein the patterned portion is uniformly distributed on the surface of the polishing pad.  
     
     
         3 . The polishing pad of  claim 1 , wherein the patterned portion is randomly distributed on the surface of the polishing pad.  
     
     
         4 . The polishing pad of  claim 1 , wherein the patterned portion comprises one or more features selected from the group consisting of XY crosshatch, spirals, concentric rings, a plurality of isolated regions, semi-circular lines, and straight lines.  
     
     
         5 . The polishing pad of  claim 1 , wherein the non-patterned portion has a density of about 0.2 g/cm 3  to about 1.1 g/cm 3 .  
     
     
         6 . The polishing pad of  claim 1 , wherein the patterned portion has at least one density of about 0.5 g/cm 3  or higher.  
     
     
         7 . The polishing pad of  claim 5 , wherein the patterned portion has a density that is about 0.1 to about 0.2 g/cm 3  higher than the density of the non-patterned portion.  
     
     
         8 . The polishing pad of  claim 1 , wherein the ratio of surface area of the patterned portion to non-patterned portion is about 95:5 to about 50:50.  
     
     
         9 . The polishing pad of  claim 1 , wherein the patterned portion comprises patterned features having a minimum dimension of about 2 mm or more.  
     
     
         10 . The polishing pad of  claim 1 , wherein the thermoplastic resin is selected from the group consisting of polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polymethacrylate, polyether, polyethylene, polyamide, polyurethane, polypropylene, and copolymers and mixtures thereof.  
     
     
         11 . The polishing pad of  claim 9 , wherein the thermoplastic resin is a urethane resin.  
     
     
         12 . The polishing pad of  claim 1 , wherein the patterned portion has at least one density that is higher than the non-patterned portion of the polishing pad.  
     
     
         13 . The polishing pad of  claim 1 , wherein the patterned portion has a lower void volume than the non-patterned portion of the polishing pad.  
     
     
         14 . The polishing pad of  claim 1 , the patterned portion further comprises one or more features selected from the group consisting of grooves and translucent window regions.  
     
     
         15 . A method for producing a polishing pad comprising: 
 (a) providing a polishing pad with a first density comprising particles of a thermoplastic resin,    (b) heating a portion of the polishing pad to cause the thermoplastic resin particles to flow, and    (c) cooling the polishing pad, thereby causing the flowed thermoplastic resin particles to solidify with a second density that is higher than the first density and forming a polishing pad having a non-patterned portion with the first density and a patterned portion with one or more densities that differ from the density of the non-patterned portion.    
     
     
         16 . The method of  claim 15 , wherein the thermoplastic resin is selected from the group consisting of polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polymethacrylate, polyether, polyethylene, polyamide, polyurethane, polypropylene, and copolymers and mixtures thereof.  
     
     
         17 . The method of  claim 15 , wherein the thermoplastic resin is a urethane resin.  
     
     
         18 . The method of  claim 15 , wherein a portion of the polishing pad is heated by contacting the polishing pad with one or more patterned rollers.  
     
     
         19 . The method of  claim 18 , wherein the patterned rollers comprise raised features mounted onto a cylinder.  
     
     
         20 . The method of  claim 15 , wherein a portion of the polishing pad is heated by contacting the polishing pad with a pin board.  
     
     
         21 . The method of  claim 15 , wherein a portion of the polishing pad is heated by contacting the polishing pad with a patterned mask in the presence of an external heat or radiation source.  
     
     
         22 . The method of  claim 15 , wherein a portion of the polishing pad is heated by contacting the polishing pad with jets of hot air.  
     
     
         23 . A chemical-mechanical polishing apparatus comprising: 
 (a) a platen that rotates,    (b) a polishing pad of  claim 1 , wherein the polishing pad is in contact with the platen and rotates with the platen, and    (c) a carrier that holds a substrate to be polished by contacting the surface of the polishing pad intended to contact a substrate to be polished.    
     
     
         24 . A method of polishing comprising: 
 (a) contacting a substrate with the polishing pad of  claim 1  and a polishing composition,    (b) moving the substrate relative to the polishing pad to abrade at least a portion of the substrate to polish the substrate.    
     
     
         25 . The method of  claim 24 , wherein the substrate comprises an insulating layer selected from silicon dioxide, silicon nitride, and a dielectric material having a dielectric constant of about 3.5 or lower.  
     
     
         26 . The method of  claim 24 , wherein the substrate comprises a metal-containing layer comprising copper, tantalum, tungsten, aluminum, nickel, titanium, platinum, ruthenium, rhodium, or iridium.  
     
     
         27 . The method of  claim 24 , wherein the polishing composition comprises an abrasive, a liquid carrier, and optionally an oxidizer or complexing agent.