Etch solution for selectively removing silicon

Abstract

An etch solution that comprises tetramethylammonium hydroxide (“TMAH”) and at least one organic solvent. The etch solution may be substantially free of water. The etch solution is formulated to selectively etch a silicon layer relative to other layers on an integrated circuit. The TMAH may be present in an amount ranging from approximately 1% by weight to approximately 10% by weight. The at least one organic solvent may be selected from the group consisting of isopropanol, butanol, hexanol, phenol, glycol, glycerol, ethylene glycol, propylene glycol, glycerin, and mixtures thereof. A method of selectively etching a silicon layer and a method of removing a heat-affected zone (“HAZ”) on an integrated circuit are also disclosed.

1 . An etch solution comprising tetramethylammonium hydroxide (“TMAH”) and at least one organic solvent, wherein the etch solution is formulated to selectively etch a silicon layer relative to at least one of a metal layer, an oxide layer, a polyimide layer, and a nitride layer.  
   
   
       2 . The etch solution of  claim 1 , wherein the at least one organic solvent comprises at least one hydroxyl group.  
   
   
       3 . The etch solution of  claim 2 , wherein the at least one hydroxyl group is capable of dissociating and forming at least one hydroxyl ion.  
   
   
       4 . The etch solution of  claim 1 , wherein the at least one organic solvent is selected from the group consisting of isopropanol, butanol, hexanol, phenol, glycol, glycerol, ethylene glycol, propylene glycol, glycerin, and mixtures thereof.  
   
   
       5 . The etch solution of  claim 1 , wherein the at least one organic solvent comprises propylene glycol.  
   
   
       6 . The etch solution of  claim 1 , wherein the etch solution is substantially free of water.  
   
   
       7 . The etch solution of  claim 1 , wherein the TMAH is present in an amount ranging from approximately 1% by weight to approximately 10% by weight.  
   
   
       8 . The etch solution of  claim 1 , wherein the TMAH is present at approximately 6% by weight.  
   
   
       9 . The etch solution of  claim 1 , wherein the etch solution comprises approximately 6% TMAH and approximately 94% propylene glycol.