Processes and solutions for substrate cleaning and electroless deposition

Abstract

This invention pertains to fabrication of devices. One embodiment is a method of substrate cleaning and electroless deposition of a cap layer for an integrated circuit. The method is performed on a substrate having a surface comprising a metal and dielectric damascene metallization layer. The method comprises exposing the surface of the substrate to a cleaning solution sufficient to clean the surface of the substrate and exposing the surface of the substrate to an electroless deposition solution sufficient to deposit the cap layer. Other embodiments of the present invention include solutions to clean the substrate and solutions to accomplish electroless deposition.

What is claimed is: 
     
         1 . A cleaning solution for cleaning a substrate for electroless deposition of a cap layer on the substrate, the cleaning solution comprising one or more hydroxycarboxylic acid(s) or one or more non-alkali metal salt(s) of one or more hydroxycarboxylic acid(s). 
     
     
         2 . The cleaning solution of  claim 1  having a pH >0.5 and <2.5 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); and 
 optionally, one or more pH adjustor(s). 
 
     
     
         3 . The cleaning solution of  claim 1  having a pH >2.5 and <5 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); and 
 optionally, one or more complexing agent(s) for Cu(I) ions. 
 
     
     
         4 . The cleaning solution of  claim 1  having a pH >5 and <8 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); 
 optionally, one or more complexing agent(s) for Cu(I) ions; 
 optionally, one or more corrosion inhibitor(s) substantially free of nitrogen and substantially free of sulfur; and 
 optionally, one or more oxygen scavenger(s). 
 
     
     
         5 . The cleaning solution of  claim 1  having a pH >8 and <13 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); 
 optionally, one or more complexing agent(s) for Cu(I) ions; 
 optionally, one or more corrosion inhibitor(s) substantially free of nitrogen and substantially free of sulfur; and 
 optionally, one or more oxygen scavenger(s). 
 
     
     
         6 . The cleaning solution of  claim 1  having a pH <2.5 and further comprising:
 optionally, one or more surfactant(s); 
 optionally, one or more reducing agent(s); and 
 optionally, one or more pH adjustor(s). 
 
     
     
         7 . The cleaning solution of  claim 1  having a pH >0.5 and <2.5 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); and 
 one or more fluoride compound(s) selected from the group consisting of hydrogen fluoride, tetrafluoroborate, and non-metal salts of hydrofluoric acid. 
 
     
     
         8 . The cleaning solution of  claim 1  having a pH >2.5 and <5 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); 
 optionally, one or more complexing agent(s) for Cu(I) ions; and 
 one or more fluoride compound(s) selected from the group consisting of hydrogen fluoride, tetrafluoroborate, and non-metal salts of hydrofluoric acid. 
 
     
     
         9 . The cleaning solution of  claim 1  having a pH >5 and <8 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); 
 optionally, one or more complexing agent(s) for Cu(I) ions; 
 optionally, one or more corrosion inhibitor(s) substantially free of nitrogen and substantially free of sulfur; 
 optionally, one or more oxygen scavenger(s); and 
 one or more fluoride compound(s) selected from the group consisting of hydrogen fluoride, tetrafluoroborate, and non-metal salts of hydrofluoric acid. 
 
     
     
         10 . The cleaning solution of  claim 1  having a pH >8 and <13 and further comprising:
 one or more surfactant(s); 
 one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); 
 optionally, one or more complexing agent(s) for Cu(I) ions; 
 optionally, one or more corrosion inhibitor(s) substantially free of nitrogen and substantially free of sulfur; 
 optionally, one or more oxygen scavenger(s); and 
 one or more fluoride compound(s) selected from the group consisting of hydrogen fluoride, tetrafluoroborate, and non-metal salts of hydrofluoric acid. 
 
     
     
         11 . The cleaning solution of  claim 1  having a pH <2.5 and further comprising:
 optionally, one or more surfactant(s); 
 optionally, one or more reducing agent(s); 
 optionally, one or more pH adjustor(s); and 
 one or more fluoride compound(s) selected from the group consisting of hydrogen fluoride, tetrafluoroborate, and non-metal salts of hydrofluoric acid; 
 the pH of the cleaning solution is. 
 
     
     
         12 . The cleaning solution of  claim 1  having a pH <2.5 and further comprising:
 one or more oxidizer(s); 
 optionally, one or more surfactant(s); and 
 optionally, one or more pH adjustor(s). 
 
     
     
         13 . The cleaning solution of  claim 1  having a pH >1 and <6 and further comprising:
 one or more surfactant(s); 
 optionally, one or more reducing agent(s); and 
 optionally, one or more pH adjustor(s); 
 
       wherein the electroless deposition of the cap layer is accomplished using an electroless deposition solution comprising:
 the one or more hydroxycarboxylic acid(s) or the one or more non-alkali metal salt(s) of the one or more hydroxycarboxylic acid(s); 
 the one or more surfactant(s); 
 optionally, the one or more reducing agent(s); and 
 optionally, the one or more pH adjustor(s). 
 
     
     
         14 . The cleaning solution of  claim 1  having a pH >1 and <6 and further comprising:
 optionally, one or more surfactant(s); 
 optionally, one or more reducing agent(s); and 
 optionally, one or more pH adjustor(s); 
 
       wherein the electroless deposition of the cap layer is accomplished using an electroless deposition solution comprising:
 the one or more hydroxycarboxylic acid(s) or the one or more non-alkali metal salt(s) of the one or more hydroxycarboxylic acid(s); 
 
       one or more surfactant(s);
 optionally, the one or more reducing agent(s); and 
 optionally, the one or more pH adjustor(s).