Method and apparatus for coating a wafer

Abstract

Disclosed is a method and apparatus for coating liquid films on to the surface of a wafer substrate by rotating the substrate at a speed sufficient to cause a liquid, through centrifugal effect, to flow outwardly toward the perimeter of the surface and form a substantially uniform thickness liquid coating thereon and starting at the central region of the wafer surface and moving radially outward therefrom, spraying a fine mist of the liquid to the surface of the wafer.

I claim:  
     
         1 . A process for applying solutions on a semiconductor wafer which comprises: 
 (a) rotating a substrate about a central point thereof;    (b) dispensing a solution mist from a spray nozzle onto a top surface of said rotating substrate;    (c) said dispensing nozzle moving radially between the central axis and an edge of the substrate while dispensing said solution.    
     
     
         2 . The process of  claim 1  wherein the rotational speed of the semiconductor wafer is. less than 2500 rpm.  
     
     
         3 . The process of  claim 2  wherein the spray nozzle is selected from the list consisting of atomizer nozzle and airless spray-mist nozzle.  
     
     
         4 . A method for forming a coating upon a planar substrate having an upper surface which comprises (a) rotating the substrate at a speed sufficient through centrifugal effect to cause a solution to flow outwardly toward the perimeter of the surface and form a substantially uniform thickness liquid coating thereon, (b) starting at the central region of the planar surface and moving radially outward therefrom, and (c) spraying a mist of the liquid to the surface.  
     
     
         5 . The process of  claim 4  wherein the rotational speed of the semiconductor wafer is less than 2500 rpm.  
     
     
         6 . A process for applying solutions on a substrate which comprises: 
 (a) rotating a substrate about a central point thereof;    (b) dispensing a polymer dielectric mist from a spray nozzle onto a top surface of said rotating substrate;    (c) said dispensing nozzle moving radially between the central axis and an edge of the substrate while dispensing said solution.    
     
     
         7 . An coating apparatus for coating a wafer of known diameter with a substantially uniform coating of a solution, the apparatus comprising: 
 (a) a containment bowl;    (b) a rotatable spin chuck mounted inside the containment bowl;    (c) a wafer attachment surface on the chuck;    (d) a dispersing mist spray nozzle moveably positioned above the wafer attachment surface.