Method for treating an object using ultra-violet light

Abstract

A method for treating an object is provided. The method comprises supporting the object above a level of a process liquid and applying megasonic energy to said process liquid to form a vapor from the liquid. The vapor reacts with a surface of the object to process the object. The level of the process liquid is generally maintained below the bottom of the object while processing the object with the vapor. An alternative embodiment of the method employs an acoustically generated vapor and ultraviolet (UV) light for processing objects. The UV light passes through the vapor to treat the object. The vapor and UV light react with a surface of the object to process the object. In a particular example of this embodiment, the vapor includes ozone, which reacts with the UV light to form an oxide at the surface of a semiconductor wafer. UV may also be used in conjunction with ammonia (NH 3 ) to facilitate substrate cleaning.

What is claimed is:  
     
         1 . A method for processing an object, comprising: 
 supporting the object above a level of a process liquid; and    applying megasonic energy to said process liquid to form a vapor that processes the object.    
     
     
         2 . The method of  claim 1 , wherein the object is a semiconductor wafer.  
     
     
         3 . The method of  claim 1  wherein said process liquid is contained in a process chamber of a wet processing system.  
     
     
         4 . The method of  claim 1  wherein said vapor chemically reacts with a surface of the object to clean the object.  
     
     
         5 . The method of  claim 1 , wherein said process liquid contains an acid.  
     
     
         6 . The method of  claim 5 , wherein said object is a semiconductor wafer and said vapor removes a native oxide from said wafer.  
     
     
         7 . The method of  claim 1 , wherein said process liquid contains an alcohol.  
     
     
         8 . The method of  claim 1 , further comprising moving the object relative to a level of said process liquid while applying said megasonic energy to said process liquid.  
     
     
         9 . The method of  claim 8 , wherein said moving the object relative to said liquid level comprises raising or lowering the level of said liquid.  
     
     
         10 . The method of  claim 1  further comprising: 
 diluting said process liquid.  
 
     
     
         11 . The method of  claim 10  wherein said process liquid is diluted with deionized water.  
     
     
         12 . The method of  claim 1  further comprising: 
 exposing the object to radiation that is readily absorbed by said process liquid when said process liquid is in the liquid state.  
 
     
     
         13 . The method of  claim 12  wherein said radiation is ultraviolet light.  
     
     
         14 . The method of  claim 13  further comprising: 
 introducing ozone to said process chamber.  
 
     
     
         15 . The method of  claim 14  further comprising: 
 exposing the object to ultraviolet light to form an oxide on a surface of the object.  
 
     
     
         16 . The method of  claim 12  further comprising lifting said object by gripping it at a backside thereof.  
     
     
         17 . The method of  claim 16  wherein said object is lifted with a vacuum wand.  
     
     
         18 . A method for processing a substrate in a process chamber, comprising: 
 supporting the object in the process chamber;    introducing a process liquid to the process chamber to a level below that of the object;    forming a vapor in the process chamber from said liquid;    processing the object with said vapor; and    exposing the object to ultraviolet light through said vapor.    
     
     
         19 . The method of  claim 18  wherein said vapor contains ozone (O 3 ).  
     
     
         20 . The method of  claim 18  wherein said vapor contains ammonia (NH 3 ).  
     
     
         21 . The method of  claim 18  wherein the process liquid contains deionized water.  
     
     
         22 . The method of  claim 18  wherein said vapor contains an alcohol vapor.  
     
     
         23 . The method of  claim 18  wherein said process liquid contains an acid.  
     
     
         24 . A computer readable storage medium having program code embodied therein, said program code for controlling a substrate processing system, wherein said substrate system includes one or more wet process chambers, a transducer, an ultraviolet source, and a robot arm, said program code controlling the semiconductor processing system to process a wafer in the chamber in accordance with the following: 
 introducing the substrate to said process chamber;    introducing a process liquid to said process chamber to a level below that of the substrate;    applying megasonic energy to said process liquid to form a vapor in the process chamber;    processing the substrate with said vapor; and    exposing the substrate to ultraviolet light through said vapor.    
     
     
         25 . The computer readable storage medium of  claim 24  wherein said process is an etch process.  
     
     
         26 . The computer readable storage medium of  claim 24 , wherein the vapor includes an oxygen containing gas, said ultraviolet light interacting with said oxygen containing gas to form an oxide on said substrate.