Multi-step conditioning process

Abstract

Methods and apparatuses are provided that may remove the build up of polishing by products from the polishing pad without the reduction in throughput associated with conventional ex-situ conditioning. The conditioning method comprises holding a wafer against a polishing pad with a 0 psi force, and applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force. Thereafter the conditioning fluid may be rinsed from the polishing pad or may remain on the polishing pad while polishing is commenced. The polishing apparatus has a controller programmed to perform the conditioning method.

The invention claimed is:  
     
         1 . A method configured to condition a polishing pad, the method comprising: 
 holding a wafer against a polishing pad with a 0 psi force;    applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force;    applying a rinsing fluid to the polishing pad;    increasing the force between the wafer and the polishing pad; and    applying a polishing solution to the polishing pad so as to polish the wafer.    
     
     
         2 . The method of    claim 1    wherein applying a conditioning fluid to the polishing pad comprises removing built up materials from the polishing pad.  
     
     
         3 . The method of    claim 1    wherein applying the conditioning solution to the polishing pad occurs after polishing the wafer.  
     
     
         4 . The method of    claim 3    wherein the wafer comprises copper layers.  
     
     
         5 . The method of    claim 3    wherein the conditioning fluid comprises citric acid and ammonium hydroxide.  
     
     
         6 . The method of    claim 1    further comprising conditioning the polishing pad with an abrasive element while 
 holding a wafer against a polishing pad with a 0 psi force;  
 applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force;  
 applying a rinsing fluid to the polishing pad; and  
 applying a polishing solution to the polishing pad so as to polish the wafer.  
 
     
     
         7 . The method of    claim 1    wherein the wafer comprises copper layers.  
     
     
         8 . The method of    claim 1    wherein the conditioning fluid comprises citric acid and ammonium hydroxide.  
     
     
         9 . A method configured to condition a polishing pad, the method comprising: 
 holding a wafer against a polishing pad with a 0 psi force;    applying a conditioning fluid to the polishing pad so as to remove built up materials from the polishing pad while holding the wafer against the polishing pad with a 0 psi force;    increasing the force between the wafer and the polishing pad; and    applying a polishing solution to the polishing pad.    
     
     
         10 . The method of    claim 9    wherein applying the conditioning solution to the polishing pad occurs after polishing the wafer.  
     
     
         11 . The method of    claim 9    wherein the wafer comprises copper layers.  
     
     
         12 . The method of    claim 9    wherein the conditioning fluid comprises citric acid and ammonium hydroxide.  
     
     
         13 . The method of    claim 9    further comprising conditioning the polishing pad with an abrasive element while: 
 holding a wafer against a polishing pad with a 0 psi force;  
 applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force;  
 increasing the force between the wafer and the polishing pad; and  
 applying a polishing solution to the polishing pad.  
 
     
     
         14 . An apparatus configured to condition a polishing pad, the apparatus comprising: 
 a polishing pad;    a wafer holder coupled to the polishing pad and configured to hold a wafer in contact with the polishing pad;    a conditioning arm configured to move across the polishing pad;    at least one supply line configured to supply a fluid to the polishing; and    a controller coupled to the at least one supply line and the wafer holder, the controller having a program configured to direct the wafer holder to hold the wafer against the polishing pad with a 0 psi force and further configured to direct the at least one supply line to supply a fluid to the polishing pad while the wafer holder holds the wafer against the polishing pad with a 0 psi force.    
     
     
         15 . The apparatus of    claim 14    further comprising a source of conditioning solution coupled to the first supply line, and wherein the program is adapted to supply conditioning solution to the polishing pad while the wafer holder holds the wafer against the polishing pad with 0 psi force.  
     
     
         16 . The apparatus of    claim 15    wherein the at least one supply line comprises three supply lines.  
     
     
         17 . The apparatus of    claim 16    further comprising: 
 a source of deionized water coupled to the second supply line; and  
 a source of polishing solution coupled to the third supply line.  
 
     
     
         18 . The method of    claim 9    further comprising: 
 ceasing application of the conditioning fluid so that the polishing solution dilutes the conditioning fluid.  
 
     
     
         19 . A method configured to condition a polishing pad, the method comprising: 
 determining whether a predetermined time interval has passed, and if so:    holding a wafer against a polishing pad with a 0 psi force;    applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force;    applying a rinsing fluid to the polishing pad;    increasing the force between the wafer and the polishing pad; and    applying a polishing solution to the polishing pad so as to polish the wafer.    
     
     
         20 . A method configured to condition a polishing pad, the method comprising: 
 determining whether a predetermined time interval has passed, and if so:    holding a wafer against a polishing pad with a 0 psi force;    applying a conditioning fluid to the polishing pad while holding the wafer against the polishing pad with a 0 psi force;    increasing the force between the wafer and the polishing pad; and    applying a polishing solution to the polishing pad so as to polish the wafer.    
     
     
         21 . The method of    claim 1    further comprising: 
 ceasing application of the conditioning fluid so that the rinsing fluid dilutes the conditioning fluid; and  
 ceasing application of the rinsing fluid so that the polishing solution dilutes the rinsing fluid.