High through-put copper CMP with reduced erosion and dishing

Abstract

A method of polishing copper with reduced erosion and dishing by a multi-step polishing technique is provided. In one aspect of the invention, a copper layer is polished at a first removal rate and then polished at a second removal rate less than the first removal rate. In another aspect, a computer readable medium is provided bearing instructions, the instructions arranged, when executed by one or more processors, to cause one or more processors to control a polishing system to polish the substrate surface at a first removal rate on a first platen and then polished at a second removal rate less than the first removal rate on a second platen. Further embodiments of the invention include reducing dishing by: controlling platen rotating speeds; increasing the concentration of active chemicals; and cleaning the polishing pads between substrates. Embodiments also include removing particulate material during CMP by increasing the flow rate of the chemical agent or controlling the static removal rate up to about 200 Å per minute, and recycling the chemical agent. Embodiments further include exposing the polishing pad and/or substrate surface to an inhibitor after each polishing step to reduce the static removal rate.

What is claimed is:  
     
         1 . A method of planarizing a substrate surface containing a copper or copper alloy layer disposed on a barrier layer comprising: 
 (a) polishing the substrate surface on a first platen to reduce a copper or copper alloy layer at a first removal rate; and    (b) polishing the substrate on a second platen to remove the copper or copper alloy layer at a second removal rate less than the first removal rate.    
     
     
         2 . The method according to    claim 1   , further comprising removing the barrier layer on a third platen.  
     
     
         3 . The method according to    claim 1   , wherein 
 the first removal rate greater than about 5,000 Å per minute; and    the second removal rate is between about 250 Å per minute and about 3,000 Å per minute.    
     
     
         4 . The method according to    claim 2   , wherein the barrier layer comprises tantalum (Ta) or tantalum nitride (TaN) and is disposed on a dielectric material.  
     
     
         5 . The method according to    claim 1   , wherein step (b) is performed at a selectivity of copper:barrier layer of greater than about 100:1.  
     
     
         6 . The method according to    claim 5   , wherein step (b) is performed under conditions such that dishing within the dense array is about 600 Å or less.  
     
     
         7 . The method according to    claim 6   , wherein steps (a) and (b) are performed on a rotating, stationary, or linear fixed abrasive polishing pad mounted on the first and second platens, respectively.  
     
     
         8 . The method according to    claim 7   , wherein the first and second platens are rotated during steps (a) and (b) by at less than about 60 rpm or the first and second belts disposed on the first and second platens, respectively, are moved linearly at a rate of less than about 30 inches per second.  
     
     
         9 . The method according to    claim 7   , further comprising cleaning the polishing pads by removing debris and polishing by-products between each substrate.  
     
     
         10 . The method according to    claim 7   , further comprising recycling the chemical agent.  
     
     
         11 . The method according to    claim 7   , wherein the chemical agent is delivered to the polishing pad or the substrate surface at a flow rate of about 300 milliliters per minute or more.  
     
     
         12 . The method according to    claim 7   , wherein the static removal rate of the substrate surface is about 200 Å per minute or less.  
     
     
         13 . The method according to    claim 7   , further comprising exposing the polishing pad or the substrate surface to an inhibitor after completing step (a) and prior to initiating step (b).  
     
     
         14 . The method according to    claim 2   , further comprising exposing the polishing pad or the substrate surface to an inhibitor after completing step (b) and prior to initiating removing the barrier layer.  
     
     
         15 . The method according to    claim 1   , further comprising: 
 exposing the polishing pad or the substrate surface to an inhibitor after completing step (a) and prior to initiating step (b);    exposing the polishing pad or the substrate surface to an inhibitor after completing step (b); and    recirculating the chemical agent.    
     
     
         16 . The method according to    claim 8   , wherein the polishing pad or belt temperature is about 50° C. or less.  
     
     
         17 . The method according to    claim 7   , wherein the fixed abrasive polishing pad comprising abrasive posts having a diameter between about 75 microns and about 150 microns and contact area ratio between about 10% and about 25% with the substrate surface.  
     
     
         18 . The method according to    claim 17   , wherein the abrasive posts are adhered to a backing sheet having a thickness of about 40 micron or less.  
     
     
         19 . The method according to    claim 1   , wherein the second polishing process includes a chemical agent having between about 0.2 wt. % and about 1.0 wt. % of an inhibitor.  
     
     
         20 . The method according to    claim 4   , wherein the barrier layer is removed from the substrate surface at a ratio of barrier layer to dielectric layer of greater than about 10:1.  
     
     
         21 . A computer-readable medium bearing instructions for planarizing a substrate surface, the instructions arranged, when executed by one or more processors, to cause the one or more processors to control a polishing system to perform the steps of: 
 (a) polishing the substrate surface on a first platen to reduce a copper or copper alloy layer at a first removal rate; and    (b) polishing the substrate on a second platen to remove the copper or copper alloy layer at a second removal rate, less than the first removal rate.    
     
     
         22 . The computer readable medium of    claim 21   , wherein said instructions are further arranged for removing the barrier layer on a third platen.  
     
     
         23 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for conducting step (a) at the first removal rate greater than about 5,000 Å per minute; and conducting step (b) at the second removal rate between about 250 Å per minute and about 3,000 Å per minute.  
     
     
         24 . The computer-readable medium of method    claim 22   , wherein said instructions are arranged for performing step (b) at a selectivity of copper:barrier layer of greater than about 100:1.  
     
     
         25 . The computer-readable medium of    claim 24   , wherein said instructions are arranged for performing step (b) under conditions such that dishing within the dense array is about 600 Å or less.  
     
     
         26 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for performing steps (a) and (b) on a rotating, stationary, or linear fixed abrasive polishing pad mounted on the first and second platens, respectively.  
     
     
         27 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for rotating the first and second platens during steps (a) and (b) by at less than about 60 rpm or the first and second belts disposed on the first and second platens, respectively, are moved linearly at a rate of less than about 30 inches per second.  
     
     
         28 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for CMP a plurality of substrates and cleaning the polishing pads by removing debris and CMP by-products between each substrate.  
     
     
         29 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for delivering the chemical agent to the polishing pad or the substrate surface at a flow rate of about 300 milliliters per minute or more.  
     
     
         30 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for recycling the chemical agent.  
     
     
         31 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for controlling the removal of particles during steps (a) and (b) by controlling the static etching rate up of the substrate surface up to about 200 Å per minute or less by controlling the amount of inhibitor in the chemical agent.  
     
     
         32 . The computer-readable medium of    claim 26   , wherein said instructions are arranged for exposing the polishing pad or the substrate surface to an inhibitor after completing step (a) and prior to initiating step (b).  
     
     
         33 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for exposing the polishing pad or the substrate surface to an inhibitor after completing step (b) and prior to initiating removing the barrier layer.  
     
     
         34 . The computer-readable medium of    claim 21   , wherein said instructions are further arranged for 
 exposing the polishing pad or the substrate surface to an inhibitor after completing step (a) and prior to initiating step (b);    exposing the polishing pad or the substrate surface to an inhibitor after completing step (b); and    recirculating the chemical agent.    
     
     
         35 . The computer-readable medium of    claim 27   , wherein said instructions are arranged for maintaining the polishing pad or belt temperature is about 50° C. or less.  
     
     
         36 . The computer-readable medium of    claim 22   , wherein said instructions are arranged for removing the barrier layer from the substrate surface at a ratio of barrier layer to dielectric layer of greater than about 10:1.  
     
     
         37 . The method according to    claim 15   , further comprising: 
 controlling dishing in the dense array during steps (a) and (b) by: 
 rotating the first and second platens, respectively, at less than about 60 rpm or linearly moving the first and second belts at about 30 inches per second, wherein the polishing pad temperature is about 50° C. or less.  
   
     
     
         38 . The method according to    claim 15   , further comprising: 
 controlling the removal of particles during steps (a) and (b) by:    delivering the chemical agent to the polishing pad or the substrate surface at a flow rate of at least about 300 milliliters per minute and    controlling the amount of inhibitor in the chemical agent to provide a static removal rate of the substrate surface of about 200 Å per minute or less.    
     
     
         39 . The method according to    claim 15   , further comprising: 
 controlling dishing in the dense array during steps (a) and (b) by: 
 rotating the first and second platens, respectively, at less than about 60 rpm or linearly moving the first and second belts at about 30 inches per second, wherein the polishing pad temperature is about 50° C. or less; and  
   controlling the removal of particles during steps (a) and (b) by: 
 delivering the chemical agent to the polishing pad or the substrate surface at a flow rate of at least about 300 milliliters per minute and  
   controlling the amount of inhibitor in the chemical agent to provide a static removal rate of the substrate surface of about 200 Å per minute or less.    
     
     
         40 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for controlling dishing in the dense array during steps (a) and (b) by: 
 rotating the first and second platens, respectively, at less than about 60 rpm or linearly moving the first and second belts at about 30 inches per second, wherein the polishing pad temperature is about 50° C. or less.    
     
     
         41 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for controlling the removal of particles during steps (a) and (b) by: 
 delivering the chemical agent to the polishing pad or the substrate surface at a flow rate of at least about 300 milliliters per minute and    controlling the amount of inhibitor in the chemical agent to provide a static removal rate of the substrate surface of about 200 Å per minute or less.    
     
     
         42 . The computer-readable medium of    claim 21   , wherein said instructions are arranged for: 
 controlling dishing in the dense array during steps (a) and (b) by: 
 rotating the first and second platens, respectively, at less than about 60 rpm or linearly moving the first and second belts at about 30 inches per second, wherein the polishing pad temperature is about 50° C. or less; and  
   controlling the removal of particles during steps (a) and (b) by: 
 delivering the chemical agent to the polishing pad or the substrate surface at a flow rate of at least about 300 milliliters per minute and  
   controlling the amount of inhibitor in the chemical agent to provide a static removal rate of the substrate surface of about 200 Å per minute or less.