Method and apparatus for two-step polishing

Abstract

Methods and apparatus for planarizing a substrate surface having copper containing materials thereon is provided. In one aspect, the invention provides a method for polishing a substrate including polishing the substrate with an abrasive-free polishing pad until it is substantially planarized and then polishing the substrate with a fixed abrasive polishing pad to remove residual materials disposed thereon. Another aspect of the invention provides a computer readable medium bearing instructions for performing the method described herein. In another aspect, the invention provides a system for processing substrates including a first platen, an abrasive-free polishing pad disposed on the first platen, a second platen, a fixed abrasive polishing pad disposed on the second platen, and a computer based controller configured to cause the system to polish the substrate with an abrasive-free polishing pad; and then to polish the substrate with a fixed abrasive polishing pad to remove residual materials disposed thereon.

What is claimed is:  
     
         1 . A method for polishing a substrate, comprising: 
 polishing the substrate with an abrasive-free polishing pad until it is substantially planarized; and then    polishing the substrate with a fixed abrasive polishing pad to remove residual materials disposed thereon.    
     
     
         2 . The method of  claim 1 , wherein the abrasive-free polishing pad is disposed on a first platen of a polishing apparatus and the fixed abrasive polishing pad is disposed on a second platen of the polishing apparatus.  
     
     
         3 . The method of  claim 2 , further comprising supplying a first polishing composition to the first platen and supplying a second polishing composition to the second platen.  
     
     
         4 . The method of  claim 1 , further comprising polishing the substrate to planarize a barrier layer disposed on the substrate.  
     
     
         5 . The method of  claim 4 , wherein polishing the substrate to planarize a barrier layer comprises supplying with a third polishing composition to a third platen of the polishing apparatus and polishing the substrate with a second abrasive-free polishing pad disposed on the third platen.  
     
     
         6 . A method for planarizing a substrate surface, comprising: 
 chemical mechanical polishing the substrate surface with an abrasive-free first polishing composition with an abrasive-free polishing pad on a first polishing platen of a polishing apparatus to substantially remove bulk copper containing materials disposed on a substrate surface; and then    chemical mechanical polishing the substrate surface with a second polishing composition with a fixed abrasive polishing pad on a second polishing platen of the polishing apparatus to remove residual copper containing materials.    
     
     
         7 . The method of  claim 6 , wherein the bulk copper containing materials and the residual copper containing materials comprise copper, doped copper, or copper alloys.  
     
     
         8 . The method of  claim 6 , further comprising chemical mechanical polishing the substrate with an abrasive-free third polishing composition on a second abrasive free polishing pad at a third platen of the polishing apparatus to planarize a barrier layer disposed on the substrate.  
     
     
         9 . A method for processing a substrate, comprising: 
 providing a substrate having a barrier layer and a copper containing material disposed thereon to a first platen containing an abrasive-free polishing pad;    polishing the substrate at a first removal rate with an abrasive-free first polishing composition to substantially remove the copper containing material disposed thereon;    providing the substrate to a second platen containing a fixed abrasive polishing pad; and    polishing the substrate at a second removal rate less than the first removal rate with a second polishing composition to remove residual copper containing materials disposed thereon.    
     
     
         10 . The method of  claim 9 , wherein the first removal rate comprises removing the copper containing material between about 4000 Å and about 10000 Å per minute.  
     
     
         11 . The method of  claim 9 , wherein the second removal rate comprises removing the copper containing material residue up to about 4000 Å per minute.  
     
     
         12 . The method of  claim 9 , further comprising supplying a first polishing composition to the first platen and supplying a second polishing composition to the second platen.  
     
     
         13 . The method of  claim 9 , further comprising providing the substrate to a third platen containing a second abrasive-free polishing pad disposed thereon and polishing the substrate to remove the barrier layer.  
     
     
         14 . A system for processing substrates, comprising: 
 a first platen adapted for polishing a substrate with an abrasive-free first polishing composition;    an abrasive-free polishing pad disposed on the first platen;    a second platen adapted for polishing the substrate with a second polishing composition;    a fixed abrasive polishing pad disposed on the second platen; and    a computer based controller configured to cause the system to perform a method comprising: 
 polishing the substrate with an abrasive-free polishing pad until it is substantially planarized; and then  
 polishing the substrate with a fixed abrasive polishing pad to remove residual materials disposed thereon.  
   
     
     
         15 . The system of  claim 14 , further comprising a third platen adapted for polishing a barrier layer on the substrate with an abrasive-free third polishing composition, and an abrasive-free polishing pad disposed on third platen.  
     
     
         16 . The system of  claim 15 , wherein the first, second, or third platen comprises a rotational, stationary or linear polishing platform.  
     
     
         17 . The system of  claim 14 , wherein the computer based controller configured to cause the system to perform a method further comprising polishing the barrier layer on the substrate with an abrasive-free polishing pad until it is substantially planarized.  
     
     
         18 . The system of  claim 14 , further comprising: 
 a carousel;    at least two substrate head assemblies suspended from the carousel and capable of holding a substrate thereon; and    a positioning member coupled to the carousel to move the carousel and position the substrate head assemblies over a selected platen.    
     
     
         19 . A computer readable medium bearing instructions for planarizing a substrate surface, the instructions arranged, when executed by one or more processors, to cause one or more processors to control a chemical mechanical system to perform: 
 (a) polishing the substrate with an abrasive-free polishing pad until it is substantially planarized; and then    (b) polishing the substrate with a fixed abrasive polishing pad to remove residual materials disposed thereon.    
     
     
         20 . The computer readable medium of  claim 19 , wherein the instructions are arranged for polishing the substrate with the abrasive-free polishing pad on a rotating, stationary or linear first platen and polishing the substrate with the fixed abrasive polishing pad on a rotating, stationary or linear second platen.  
     
     
         21 . The computer readable medium of  claim 19 , wherein the instructions are arranged for polishing the substrate at a first removal rate with the abrasive-free first polishing composition to substantially remove the bulk copper containing material disposed thereon, providing the substrate to a second platen containing a fixed abrasive polishing pad, and polishing the substrate at a second removal rate less than the first removal rate with a second composition to remove residual copper containing materials disposed thereon.  
     
     
         22 . The computer readable medium of  claim 19 , wherein the instructions are further arranged for chemical mechanical polishing the substrate to remove a barrier layer disposed on the substrate with an abrasive-free third polishing composition abrasive-free polishing pad mounted on a rotating, stationary or linear third platen.  
     
     
         23 . The computer readable medium of  claim 19 , wherein a computer based control system is used to sequence and control the instructions for planarizing a substrate surface contained in the computer readable medium.