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 . A semiconductor die comprising: 
 a substrate; and    an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface structured by abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution, wherein the planarizing solution includes an oxidizing solution having at least one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide.    
   
   
       2 . The semiconductor die of  claim 1 , wherein the planarizing solution includes at least one buffer agent, the buffer agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
   
   
       3 . The semiconductor die of  claim 1 , wherein the planarizing solution has a pH of approximately 1 to 6.  
   
   
       4 . The semiconductor die of  claim 1 , wherein the planarizing solution is an oxidizing solution substantially without an agent to operate as an etching agent.  
   
   
       5 . The semiconductor die of  claim 1 , wherein the oxidizing agent is selected from the group consisting of ammonium heptamolybdate, ceric ammonium nitrate, and ceric ammonium sulfate.  
   
   
       6 . A semiconductor die comprising: 
 a substrate; and    an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface structured by abrading the titanium nitride layer with a planarizing surface of a planarizing medium having a fixed-abrasive planarizing pad and a planarizing solution, wherein the planarizing solution includes an oxidizing solution having an oxidizer and a buffer in aqueous solution, the oxidizer selected from the group consisting of ammonium heptamolybdate, ceric ammonium nitrate, and ceric ammonium sulfate, the oxidizing solution comprising approximately 1% to 10% by weight of the oxidizer and approximately 0% to 10% by weight of the buffer.    
   
   
       7 . The semiconductor die of  claim 6 , wherein the buffer is from a group consisting of ammonium oxalate and diammonium phosphate.  
   
   
       8 . The semiconductor die of  claim 6 , wherein the oxidizing solution has a pH of approximately 1.5 to 4.  
   
   
       9 . A semiconductor die comprising: 
 a substrate; and    an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface structured by abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution, the planarizing solution having one oxidizing agent, the one oxidizing agent selected from the group consisting of ammonium heptamolybdate, ceric ammonium nitrate, and ceric ammonium sulfate.    
   
   
       10 . The semiconductor die of  claim 9 , wherein the planarizing solution further includes a buffer, the buffer having one buffering agent selected from the group consisting of ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
   
   
       11 . The semiconductor die of  claim 9 , wherein the planarizing solution is approximately 2% by weight of the oxidizing agent.  
   
   
       12 . A method of fabricating a semiconductor die comprising: 
 providing a substrate; and    forming an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface planarized by a method including abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution, the planarizing solution having 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 method of  claim 12 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the planarizing solution being approximately 2% by weight of the oxidizing agent.  
   
   
       14 . The method of  claim 12 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the planarizing solution having a pH of approximately 1.5 to 4.  
   
   
       15 . The method of  claim 12 , wherein the planarizing solution is an oxidizing solution substantially without an agent to operate as an etching agent.  
   
   
       16 . The method of  claim 12 , wherein the method includes selecting the oxidizing agent from the group consisting of ammonium heptamolybdate, ceric ammonium nitrate, and ceric ammonium sulfate.  
   
   
       17 . A method of fabricating a semiconductor die comprising: 
 providing a substrate; and    forming an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface planarized by a method including abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution, the planarizing solution having an oxidizer and a buffer in aqueous solution, the oxidizer having at least one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide, the planarizing solution having a pH of approximately 1 to 6.    
   
   
       18 . The method of  claim 17 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the buffer having at least one buffering agent selected from the group consisting of phosphoric acid, ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
   
   
       19 . The method of  claim 17 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the planarizing solution being approximately 2% by weight of the oxidizing agent.  
   
   
       20 . The method of  claim 12 , wherein the planarizing solution is an oxidizing solution substantially without an agent to operate as an etching agent.  
   
   
       21 . The method of  claim 12 , wherein the method includes selecting the oxidizing agent from the group consisting of ceric ammonium nitrate and ceric ammonium sulfate.  
   
   
       22 . A method of fabricating a semiconductor die comprising: 
 providing a substrate; and    forming an integrated circuit supported by the substrate, the integrated circuit having a titanium nitride layer, the titanium nitride layer having a planarized surface planarized by a method including abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution, the planarizing solution including an oxidizer and a buffer in aqueous solution, the oxidizer having at least one oxidizing agent selected from the group consisting of ammonium persulfate, ammonium heptamolybdate, ceric ammonium nitrate, ceric ammonium sulfate and hydrogen peroxide, the planarizing solution being approximately 1% to 10% by weight of the oxidizer and approximately 0% to 10% by weight of the buffer.    
   
   
       23 . The method of  claim 22 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the buffer having at least one buffering agent selected from the group consisting of phosphoric acid, ammonium acetate, ammonium oxalate, ammonium phosphate and diammonium phosphate.  
   
   
       24 . The method of  claim 22 , wherein abrading the titanium nitride layer with a planarizing surface of a planarizing medium including a fixed-abrasive planarizing pad and a planarizing solution includes the planarizing solution having a pH of approximately 1.5 to 4.  
   
   
       25 . The method of  claim 22 , wherein the planarizing solution is an oxidizing solution substantially without an agent to operate as an etching agent.  
   
   
       26 . The method of  claim 12 , wherein the method includes selecting ammonium heptamolybdate as the oxidizing agent.