Process and apparatus for treating a workpiece

Abstract

A novel chemistry, system and application technique reduces contamination of semiconductor wafers and similar substrates and enhances and expedites processing. A stream of liquid chemical is applied to the workpiece surface. Ozone is delivered either into the liquid process stream or into the process environment. The ozone is preferably generated by a high capacity ozone generator. The chemical stream is provided in the form of a liquid or vapor. A boundary layer of liquid or vapor forms on the workpiece surface. The thickness of the boundary layer is controlled. The chemical stream may include ammonium hydroxide for simultaneous particle and organic removal, another chemical to raise the pH of the solution, or other chemical additives designed to accomplish one or more specific cleaning steps.

1 . A method for processing a workpiece, comprising: 
 placing the workpiece into a chamber;    pressurizing the chamber to an above ambient pressure;    directly or indirectly heating the workpiece,    providing water vapor into the chamber, with the water vapor exceeding about 100 C; and    providing ozone gas into the chamber.    
     
     
         2 . The method of  claim 1  wherein the workpiece is coated with photoresist, and with the steam and ozone chemically reacting with and removing the photoresist.  
     
     
         3 . The method of  claim 1  wherein the water vapor forms a layer on the wafer surface, with the layer having a thickness of from about 1-100 microns.  
     
     
         4 . The method of  claim 1  wherein the water vapor forms a layer a few molecular layers thick.  
     
     
         5 . The method of  claim 2  wherein the photoresist is hydrolyzed.  
     
     
         6 . The method of  claim 1  wherein the water vapor is at about 120-130 C.  
     
     
         7 . The method of  claim 1  wherein the chamber is flat and disk-shaped.  
     
     
         8 . The method of  claim 1  wherein the ozone is provided at a concentration of at least 12% by weight.  
     
     
         9 . The method of  claim 1  wherein the ozone and water vapor are provided into the chamber for about 1-5 minutes.  
     
     
         10 . The method of  claim 1  further including heating the workpiece via contact heaters in the chamber.  
     
     
         11 . The method of  claim 1  with the ozone provided at a flow rate of at least 10 liters/minute, and at a concentration of at least 12% by weight.  
     
     
         12 . A method for removing photoresist from a wafer, comprising: 
 placing the wafer into a chamber;    directly or indirectly heating the wafer with one or more heaters in or on the chamber,    providing steam in the chamber;    providing ozone gas into the chamber;    pressurizing the chamber;    contacting the wafer with steam and ozone, with the steam and ozone chemically reacting with the photoresist; and    rinsing the wafer.    
     
     
         13 . The method of  claim 12  with the steam forming a molecular layer on a surface of the workpiece.  
     
     
         14 . The method of  claim 13  with the workpiece surface having a temperature exceeding 100 C.  
     
     
         15 . The method of  claim 12  with the photoresist having carbon-carbon bonds hydrolyzed in the presence of the steam and ozone.  
     
     
         16 . A method for cleaning a workpiece, comprising: 
 placing the workpiece into a chamber;    directly or indirectly heating the workpiece with one or more heaters,    providing heated water vapor in the chamber;    providing ozone gas into the chamber;    pressurizing the chamber to an above ambient pressure;    contacting the workpiece with heated and ozone, with the steam and ozone chemically reacting, in the presence of hydroxyl radicals, to clean the workpiece; and    rinsing the workpiece.    
     
     
         17 . The method of  claim 16  with the heated water vapor forming a layer on the workpiece, and with the ozone gas diffusing through the layer.  
     
     
         18 . The method of  claim 16  including providing the ozone gas at a concentration of at least 12% and a flow rate of at least 10 liters/minute.  
     
     
         19 . A system for cleaning a workpiece, comprising: 
 a pressurizable chamber;    a heated water vapor supply associated with the chamber;    an ozone gas supply connecting into the chamber;    a workpiece support in the chamber for supporting the workpiece; and    a workpiece heater in the chamber on or in the wafer support for directly heating the wafer.    
     
     
         20 . The system of  claim 19  with the chamber is disk-shaped.  
     
     
         21 . The system of  claim 19  with the ozone gas supply providing at least 90 grams/hour of ozone.