Fixed-abrasive chemical-mechanical planarization of titanium nitride

Abstract

Titanium nitride layers planarized may be utilized in the production of integrated circuits, and various apparatus utilizing such integrated circuits. Planarizing solutions may be used for removing titanium nitride from the surface of a substrate using a fixed-abrasive planarizing pad. The planarizing solutions take the form of an etchant solution or an oxidizing solution. The etchant solutions are aqueous solutions containing an etchant and a buffer. The etchant contains one or more etching agents selective to titanium nitride. The oxidizing solutions are aqueous solutions containing an oxidizer and a buffer. The oxidizer contains one or more oxidizing agents selective to titanium nitride. In either solution, i.e., etchant or oxidizing solution, the buffer contains one or more buffering agents.

1 . An electronic system, comprising: 
 a processor; and    a circuit module having a plurality of leads coupled to the processor, and further having a semiconductor die coupled to at least a portion of the plurality of leads, wherein the semiconductor die comprises: 
 a substrate; and  
 an integrated circuit supported by the substrate and having a titanium nitride layer, wherein the titanium nitride layer is planarized by a method comprising: 
 abrading the titanium nitride layer with a planarizing surface of a planarizing medium comprising a fixed-abrasive planarizing pad and a clean planarizing solution.  
 
   
     
     
         2 . The electronic system of  claim 1 , wherein the planarizing solution is an aqueous etchant solution comprising an etchant and a buffer, wherein the etchant comprises at least one etching agent selected from the group consisting of oxalic acid, ascorbic acid and phosphoric acid.  
     
     
         3 . The electronic system of  claim 2 , wherein the buffer comprises at least one buffering agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
     
     
         4 . The electronic system of  claim 2 , wherein the planarizing solution has a pH of approximately 1 to 5.  
     
     
         5 . The electronic system of  claim 1 , wherein the planarizing solution is an aqueous oxidizing solution comprising an oxidizer and a buffer, wherein the oxidizer comprises at least one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide.  
     
     
         6 . The electronic system of  claim 5 , wherein the buffer comprises at least one buffering agent selected from the group consisting of phosphoric acid, ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
     
     
         7 . The electronic system of  claim 5 , wherein the planarizing solution has a pH of approximately 1 to 6.  
     
     
         8 . The electronic system of  claim 1 , wherein the planarizing solution is an aqueous solution comprising approximately 1% to 5% by weight of oxalic acid and approximately 2% to 10% by weight of ammonium acetate.  
     
     
         9 . The electronic system of  claim 2 , wherein the planarizing solution further includes a thickening agent.  
     
     
         10 . The electronic system of  claim 5 , wherein the planarizing solution further includes a thickening agent.  
     
     
         11 . An electronic system, comprising: 
 a processor; and    a circuit module having a plurality of leads coupled to the processor, and further having a semiconductor die coupled to at least a portion of the plurality of leads, the semiconductor die comprising: 
 a substrate; and  
 an integrated circuit supported by the substrate and having a titanium nitride layer, the titanium nitride layer planarized by a method comprising: 
 abrading the titanium nitride layer with a planarizing surface of a planarizing medium comprising a fixed-abrasive planarizing pad and a clean planarizing solution, the planarizing solution having an oxidizer and a buffer, the planarizing solution being approximately 1% to 10% by weight of the oxidizer and approximately 0% to 10% by weight of the buffer.  
 
   
     
     
         12 . The electronic system of  claim 11 , wherein the oxidizer comprises at least one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide.  
     
     
         13 . The electronic system of  claim 11 , wherein the oxidizing solution has a pH of approximately 1.5 to 4.  
     
     
         14 . An electronic system, comprising: 
 a processor; and    a circuit module having a plurality of leads coupled to the processor, and further having a semiconductor die coupled to at least a portion of the plurality of leads, the semiconductor die comprising: 
 a substrate; and  
 an integrated circuit supported by the substrate and having a titanium nitride layer, the titanium nitride layer planarized by a method comprising: 
 abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a clean planarizing solution, the planarizing solution having an etchant, the etchant including at least one etching agent selected from the group consisting of oxalic acid, ascorbic acid and phosphoric acid, the planarizing solution having approximately 1% to 5% by weight of the etchant.  
 
   
     
     
         15 . The electronic system of  claim 14 , the planarizing solution further includes a buffer, the buffer having at least one buffering agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
     
     
         16 . The electronic system of  claim 14 , wherein the planarizing solution has a pH less than approximately 3.  
     
     
         17 . An electronic system, comprising: 
 a processor; and    a circuit module having a plurality of leads coupled to the processor, and further having a semiconductor die coupled to at least a portion of the plurality of leads, the semiconductor die comprising: 
 a substrate; and  
 an integrated circuit supported by the substrate and having a titanium nitride layer, the titanium nitride layer planarized by a method comprising: 
 abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a clean planarizing solution, the planarizing solution having an etchant, the etchant including one etching agent selected from the group consisting of oxalic acid, ascorbic acid and phosphoric acid.  
 
   
     
     
         18 . The electronic system of  claim 17 , wherein the planarizing solution further includes a buffer, the buffer having at least one buffering agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
     
     
         19 . The electronic system of  claim 18 , wherein the planarizing solution is approximately 1% to 10% by weight of the etchant and approximately 0% to 10% by weight of the buffer.  
     
     
         20 . An electronic system, comprising: 
 a processor; and    a circuit module having a plurality of leads coupled to the processor, and further having a semiconductor die coupled to at least a portion of the plurality of leads, the semiconductor die comprising: 
 a substrate; and  
 an integrated circuit supported by the substrate and having a titanium nitride layer, the titanium nitride layer planarized by a method comprising: 
 abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a clean planarizing solution, the planarizing solution having an oxidizer, the oxidizer including one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide.  
 
   
     
     
         21 . The electronic system of  claim 20 , wherein the planarizing solution further includes a buffer, the buffer having at least one buffering agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
     
     
         22 . The electronic system of  claim 21 , wherein the planarizing solution is approximately 2% by weight of the oxidizer.