Method and System for Conditioning a Polishing Pad

Abstract

A method for conditioning a polishing pad of a polishing system is provided. The method comprises performing an in-situ pad conditioning process and an ex-situ pad conditioning process outside of a polishing operation. The in-situ pad conditioning process comprises causing a pad conditioner to contact the polishing pad during the polishing operation. The ex-situ pad conditioning process comprises causing the pad conditioner to contact the polishing pad while a cleaning agent is applied to the polishing pad.

1 . A method for conditioning a polishing pad of a polishing system, the method comprising:
 performing an in-situ pad conditioning process, wherein the in-situ pad conditioning process comprises providing a slurry to the polishing pad and causing a pad conditioner to contact the polishing pad during a polishing operation, wherein the slurry comprises one or more of potassium hypochlorite, sodium hypochlorite, ammonium persulfate, potassium peroxymonosulfate, sodium permanganate, potassium permanganate, potassium periodate, and potassium persulfate, wherein the polishing operation comprises providing the slurry to the polishing pad while the polishing pad is rotating and in contact with a semiconductor workpiece surface comprising silicon carbide; and   performing an ex-situ pad conditioning process outside of the polishing operation, wherein the ex-situ pad conditioning process comprises causing the pad conditioner to contact the polishing pad while a cleaning agent is applied to the polishing pad.   
     
     
         2 . The method of  claim 1 , wherein the cleaning agent is applied to the polishing pad while the polishing pad is rotating. 
     
     
         3 . The method of  claim 1 , wherein the cleaning agent comprises a reducing agent. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the slurry comprises sodium permanganate or potassium permanganate. 
     
     
         6 . The method of  claim 1 , further comprising stopping the polishing process, wherein stopping the polishing operation comprises removing the semiconductor workpiece from contact with the polishing pad and stopping the providing of the slurry to the polishing pad. 
     
     
         7 . The method of  claim 1 , wherein the in-situ pad conditioning process is performed continuously throughout the polishing operation. 
     
     
         8 . The method of  claim 1 , wherein the in-situ pad conditioning process is performed intermittently throughout the polishing operation. 
     
     
         9 . The method of  claim 1 , further comprising stopping the in-situ pad conditioning process during the polishing operation based at least in part on a process condition. 
     
     
         10 . The method of  claim 9 , wherein the process condition is an elapsed time period since starting the in-situ pad conditioning process. 
     
     
         11 . The method of  claim 10 , wherein the elapsed time period is determined based on a rate of material removal during a polishing operation performed on at least one preceding semiconductor workpiece. 
     
     
         12 . The method of  claim 9 , wherein the process condition is a temperature of the polishing pad. 
     
     
         13 . The method of  claim 1 , wherein the method is performed for polishing a plurality of semiconductor workpieces. 
     
     
         14 . The method of  claim 13 , wherein the method comprises performing the ex-situ pad conditioning process after polishing each semiconductor workpiece of the plurality of semiconductor workpieces. 
     
     
         15 . The method of  claim 13 , wherein the method comprises performing the ex-situ pad conditioning process after every X workpieces of the plurality of semiconductor workpieces, wherein X is an integer from 2 to 10. 
     
     
         16 . The method of  claim 13 , wherein the method comprises performing the ex-situ pad conditioning process based at least in part on a process condition after completing polishing of each semiconductor workpiece of the plurality of semiconductor workpieces. 
     
     
         17 . The method of  claim 16 , wherein the process condition is a material removal rate during polishing of an immediately preceding semiconductor workpiece meeting a threshold material removal rate. 
     
     
         18 . (canceled) 
     
     
         19 . A method for conditioning a polishing pad of a polishing system, the method comprising:
 performing an in-situ pad conditioning process, wherein the in-situ pad conditioning process comprises providing a slurry to the polishing pad and causing a pad conditioner to contact the polishing pad during a polishing operation, wherein the slurry comprises one or more of potassium hypochlorite, sodium hypochlorite, ammonium persulfate, potassium peroxymonosulfate, sodium permanganate, potassium permanganate, potassium periodate, and potassium persulfate, wherein the polishing operation comprises providing the slurry to the polishing pad while the polishing pad is rotating and in contact with a semiconductor workpiece surface comprising silicon carbide;   measuring a process condition; and   changing the in-situ pad conditioning process based at least in part on the process condition.   
     
     
         20 . A system for polishing a semiconductor wafer, the system comprising:
 a platen operable to rotate about an axis;   a polishing pad coupled to the platen;   a workpiece carrier operable to bring a semiconductor workpiece surface comprising silicon carbide into contact with the polishing pad;   a pad conditioner;   a delivery system configured to deliver a slurry to the polishing pad, wherein the slurry comprises one or more of potassium hypochlorite, sodium hypochlorite, ammonium persulfate, potassium peroxymonosulfate, sodium permanganate, potassium permanganate, potassium periodate, and potassium persulfate;   a sensor configured to measure a process condition; and   a controller comprising one or more control devices operable to bring the pad conditioner into or out of contact with the polishing pad based at least in part on the process condition.   
     
     
         21 . The method of  claim 1 , wherein the slurry comprises sodium permanganate.