Method of Thermally Oxidizing Silicon Using Ozone

Abstract

A method and apparatus for oxidizing materials used in semiconductor integrated circuits, for example, for oxidizing silicon to form a dielectric gate. An ozonator is capable of producing a stream of least 70% ozone. The ozone passes into an RTP chamber through a water-cooled injector projecting into the chamber. Other gases such as hydrogen to increase oxidation rate, diluent gas such as nitrogen or O 2 , enter the chamber through another inlet. The chamber is maintained at a low pressure below 20 Toir and the substrate is advantageously maintained at a temperature less than 800° C. Alternatively, the oxidation may be performed in an LPCVD chamber including a pedestal heater and a showerhead gas injector in opposition to the pedestal.

1 . A method of treating a surface of a substrate to be formed into an integrated circuit, comprising the steps of: 
 maintaining a processing surface of said substrate at a temperature; and    flowing from a first gas port into a processing chamber accommodating said substrate an oxygen-based gas mixture containing at least 30% ozone.    
   
   
       2 . The method of  claim 1 , wherein said gas mixture contains at least 50% ozone.  
   
   
       3 . The method of  claim 2 , wherein said gas mixture contains at least 70% ozone.  
   
   
       4 . The method of  claim 3 , wherein said gas mixture contains at least 90% ozone.  
   
   
       5 . The method of  claim 1 , wherein said substrate comprises a silicon-containing material and said ozone oxidizes the silicon-containing material.  
   
   
       6 . The method of  claim 5 , further comprising flowing into said processing chamber hydrogen.  
   
   
       7 . The method of  claim 6 , wherein said hydrogen flows into said processing chamber through a second port.  
   
   
       8 . The method of  claim 5 , further comprising flowing oxygen gas into said chamber through a second port.  
   
   
       9 . The method of  claim 5  wherein the temperature is less than 800° C.  
   
   
       10 . The method of  claim 9 , wherein the temperature is less than 600° C.  
   
   
       11 . The method of  claim 10 , wherein the temperature is less than 400° C.  
   
   
       12 . The method of  claim 1 , wherein the gas mixture is not excited into a plasma adjacent said substrate.  
   
   
       13 . The method of  claim 1 , wherein the maintaining step is performed by radiant lamps directed at the substrate.  
   
   
       14 . The method of  claim 1 , wherein said flowing step includes flowing said gas mixture into a said processing chamber through an injector projecting into said processing chamber and further comprising cooling said injector with a cooling liquid.  
   
   
       15 . The method of  claim 1 , wherein the maintaining step includes electrically heating a pedestal accommodated within said processing chamber and supporting the substrate.  
   
   
       16 . The method of  claim 15 , wherein said flowing step includes flowing said gas mixture into a gas manifold separated from the processing chamber by a showerhead including a plurality of apertures therethough and disposed in opposition to the pedestal.  
   
   
       17 . The method of  claim 1 , further comprising flowing molecular oxygen gas through an ozonator external of the chamber to produce said oxygen-based gas mixture.  
   
   
       18 . The method of  claim 1 , wherein a pressure within the processing chamber is maintained no higher than 20 Torr.  
   
   
       19 . The method of  claim 18 , where the pressure is maintained no higher than 5 Torr.  
   
   
       20 . The method of  claim 1 , further comprising flowing another processing gas into the processing chamber from a port different than a port admitting said oxygen-based gas into said processing chamber.