Apparatus and method to improve resist line roughness in semiconductor wafer processing

Abstract

A process for prohibiting amino group transport from the top surface of a layered semiconductor wafer to a photoresist layer introduces a thin film oxynitride over the silicon nitride layer using a high temperature step of nitrous oxide (N 2 O) plus oxygen (O 2 ) at approximately 300° C. for about 50 to 120 seconds. By oxidizing the silicon nitride layer, the roughness resulting from the adverse affects of amino group transport eliminated. Moreover, this high temperature step, non-plasma process can be used with the more advanced 193 nanometer technology, and is not limited to the 248 nanometer technology. A second method for exposing the silicon nitride layer to an oxidizing ambient, prior to the application of antireflective coating, introduces a mixture of N 2 H 2 and oxygen (O 2 ) ash at a temperature greater than or equal to 250° C. for approximately six minutes. This is followed by an O 2 plasma clean and/or an Ozone clean, and then the subsequent layering of the ARC and photoresist.

1 - 20 . (canceled)  
   
   
       21 . A layered semiconductor substrate prohibiting amino group initiated line distortion in a photoresist layer comprising: 
 a silicon nitride layer on top of said layered substrate;    an oxynitride layer directly over and in contact with said silicon nitride layer, as a means to prevent amino group transport;    an antireflective coating layer on said oxynitride layer after said substrate is treated to plasma exposure, said antireflective coating applied such that said oxynitride layer is directly between and in contact with said silicon nitride layer and said antireflective coating layer; and    a photoresist layer directly over and in contact with said antireflective coating layer.    
   
   
       22 . (canceled)  
   
   
       23 . The method of  claim 21  further comprising said oxynitride layer having a thickness of less than 100 angstroms.  
   
   
       24 . The method of  claim 21  further comprising said oxynitride layer having a thickness of less than 10 angstroms.  
   
   
       25 . The method of  claim 21  further comprising said oxynitride layer having a thickness of approximately 5 to 10 angstroms.  
   
   
       26 . The method of  claim 21  comprising said oxynitride layer having a compound of the form SiO x N y .  
   
   
       27 . The method of  claim 21  wherein said antireflective coating is either an organic or inorganic material.  
   
   
       28 . The method of  claim 21  wherein said oxynitride layer is deposited using an LPCVD process.