CMP slurry

Abstract

RNA, DNA and the building blocks forming these compounds provide significant enhancement in the selectivity of a CMP slurry for removing silicon dioxide in preference to silicon nitride during chemical-mechanical polishing in the manufacture of semiconductor wafers and chips by STI.

1 . A CMP slurry comprising a liquid, abrasive particles and a selectivity enhancer comprising a nucleic acid related compound.  
     
     
         2 . The CMP slurry of  claim 1 , wherein the liquid is water and the slurry contains at about 0.01 wt. % abrasive particles.  
     
     
         3 . The slurry of  claim 2 , wherein the nucleic acid related compound is RNA or DNA, a nitrogen-containing precursor of RNA or DNA, a nitrogen-containing decomposition product of RNA or DNA, or mixture of any of these compounds.  
     
     
         4 . The slurry of  claim 3 , wherein the nucleic acid related compound is RNA or DNA.  
     
     
         5 . The slurry of  claim 3 , wherein the nucleic acid related compound is a nucleotide.  
     
     
         6 . The slurry of  claim 5 , wherein the nucleotide is adenosine 5′-phosphate, 2′-deoxyadenosine 5′-phosphate, guanosine 5′-phosphate, 2′-deoxyguanosine 5′-phosphate, cytidine 5′-phosphate, 2′-deoxycytidine 5′-phosphate, uridine 5′-phosphate, 2′-deoxythymidine 5′-phosphate, adenosine 5′-diphosphate, 2′-deoxyadenosine 5′-diphosphate, guanosine 5′-diphosphate 2′-deoxyguanosine 5′-diphosphate, cytidine 5′-diphosphate, 2′-deoxycytidine 5′-diphosphate, uridine 5′-diphosphate, 2′-deoxythymidine 5′-diphosphate, adenosine 5′-triphosphate, 2′-deoxyadenosine 5′-triphosphate, guanosine 5′-triphosphate, 2′-deoxyguanosine 5′-triphosphate, cytidine 5′-triphosphate, 2′-deoxycytidine 5′-triphosphate, uridine 5′-triphosphate, 2′-deoxythymidine 5′-triphosphate, or mixtures thereof.  
     
     
         7 . The slurry of  claim 3 , wherein the nucleic acid compound is a nucleoside.  
     
     
         8 . The slurry of  claim 7 , wherein the nucleoside is adenosine, 2′-deoxyadenosine, guanosine, 2′-deoxyguanosine, cytidine, 2′-deoxycytidine, uridine, 2′-deoxythymidine or mixtures thereof.  
     
     
         9 . The slurry of  claim 3 , wherein the nucleic acid related compound is adenine, guanine, cytosine, uracil, thymine or mixtures thereof.  
     
     
         10 . The slurry of  claim 3 , wherein the slurry contains a mixture of a cationic surfactant, an anionic surfactant and a nonionic surfactant.  
     
     
         11 . The slurry of  claim 10 , 
 wherein the cationic surfactant is an alkyltrimethylammonium halide, an alkylbenzyldimethylammonium halide, a pyridiniumalkyl halide, an alkylammonium ester, or mixtures thereof,    wherein the anionic surfactant is a polymer containing carboxylic acid groups, an ammonium, sodium, potassium, cesium, monoethanolamine, diethanolamine, or triethanolamine salt of such a polymer, or mixtures thereof, and    wherein the nonionic surfactant is a water soluble polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, or mixtures thereof.    
     
     
         12 . The slurry of  claim 11 , wherein the cationic surfactant is hexadecyltrimethylammonium bromide, hexadecylbenzyldimethylammonium bromide, dodecylbenzyldimethylammonium bromide, cetylpyridinium chloride, dodecylammonium acetate, or mixtures thereof.  
     
     
         13 . The slurry of  claim 1 , wherein the nucleic acid related compound is a mixture of uridine and cytidine.  
     
     
         14 . A chemical-mechanical polishing process for selectively removing silicon dioxide from the surface of a workpiece containing surface areas of silicon dioxide and surface areas of silicon nitride in which the surface to be polished is contacted with a polishing pad and a CMP slurry is applied to the interface between the polishing pad the surface to be polished, 
 wherein the CMP slurry comprises a liquid, abrasive particles and a selectivity enhancer for enhancing the removal of silicon dioxide in preference to the removal of silicon nitride, the selectivity enhancer comprising a nucleic acid related compound.    
     
     
         15 . The process of  claim 14 , wherein the liquid comprises water and the slurry contains at about 0.01 wt. % abrasive particles.  
     
     
         16 . The process of  claim 15 , wherein the nucleic acid related compound is RNA or DNA, a nitrogen-containing precursor of RNA or DNA, a nitrogen-containing decomposition product of RNA or DNA, or mixture of any of these compounds.  
     
     
         17 . The process of  claim 16 , wherein the nucleic acid related compound comprises RNA or DNA.  
     
     
         18 . The process of  claim 17 , wherein the nucleic acid related compound comprises a nucleotide.  
     
     
         19 . The process of  claim 16 , wherein the nucleic acid related compound comprises a nucleoside.  
     
     
         20 . The process of  claim 16 , wherein the nucleic acid related compound comprises adenine, guanine, cytosine, uracil, thymine or mixtures thereof.  
     
     
         21 . The process of  claim 16 , wherein the nucleic acid related compound is a mixture of uridine and cytidine.