Method and apparatus for coating a wafer

Abstract

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 from one edge of the wafer surface and moving radially outward therefrom in a single direction, spraying a fine mist of the liquid to the surface of the wafer.

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 . A method of coating a surface having an edge and a center, wherein said edge and said center define a radius, and wherein said surface spins around an axis through said center, said method comprising: 
 providing a nozzle near said edge of said surface; and    moving said nozzle along at most a portion of said radius.    
   
   
       3 . The method in  claim 2 , wherein said step of moving said nozzle further comprises moving said nozzle toward said center of said surface.  
   
   
       4 . The method in  claim 3 , wherein said step of moving said nozzle further comprises moving said nozzle toward a point external to said center.  
   
   
       5 . The method in  claim 4 , further comprising a step of dispersing a coating material from said nozzle during said step of moving said nozzle.  
   
   
       6 . A method of depositing a material at least partially along a diameter of a workpiece including a semiconductive material, said workpiece having an edge, a center, and an opposite edge, wherein said method comprises: 
 providing a nozzle;    positioning said nozzle generally over said edge of said workpiece including said semiconductive material;    moving said nozzle in no more than one direction along said diameter; and    spraying said material from said nozzle while moving said nozzle.    
   
   
       7 . The method in  claim 6 , further comprising a step of stopping motion of said nozzle generally over said center.  
   
   
       8 . The method in  claim 6 , further comprising a step of stopping motion of said nozzle after said nozzle passes over said center.  
   
   
       9 . The method in  claim 8 , wherein said step of stopping motion of said nozzle further comprises stopping motion of said nozzle when said nozzle is over said opposite edge.  
   
   
       10 . A method of coating a wafer with a solution, comprising: 
 generating a centrifugal force associated with said wafer;    spraying said solution from a nozzle onto said wafer; and    moving said nozzle while spraying, further comprising: 
 maintaining a generally constant direction of movement, and  
 moving said nozzle counter to said centrifugal force.  
   
   
   
       11 . The method in  claim 10 , wherein said step of moving said nozzle while spraying further comprises moving said nozzle concurrent with said centrifugal force.  
   
   
       12 . A method of propelling a nozzle over a spinning wafer, comprising: 
 initiating a motion of said nozzle in a first area concurrent with a generally greatest magnitude of centrifugal force on said wafer;    completing said motion in a second area concurrent with a generally least magnitude of centrifugal force on said wafer;    moving said nozzle through a third area between said initiating step and said completing step, wherein said third area is concurrent with a decreasing magnitude of centrifugal force; and    avoiding moving said nozzle through a fourth area concurrent with an increasing magnitude of centrifugal force while spraying a material from said nozzle.    
   
   
       13 . A method of moving a dispenser and a chuck, comprising: 
 defining a generally circular direction of rotation with said chuck; and    defining a generally non-reciprocal direction of motion with said dispenser, further comprising: 
 facing a first side of said dispenser against said direction of rotation, and  
 subsequently facing a second side of said dispenser against said direction of rotation.  
   
   
   
       14 . The method in  claim 13 , wherein said step of defining a generally non-reciprocal direction of motion with said dispenser further comprises defining a generally unidirectional line of motion with said dispenser.  
   
   
       15 . A method of coating a wafer having a center, comprising: 
 providing an outward force from said wafer; and    spraying a mist from a source only while said source is moving counter to said outward force.    
   
   
       16 . The method in  claim 15 , wherein said step of providing an outward force from said wafer further comprises spinning said wafer around said center.  
   
   
       17 . A method of moving a chuck and a dispenser, comprising: 
 dispensing a fluid from said dispenser while said dispenser is moving in only one direction from an initial position to a final position; and    rotating said chuck around a chuck center, further comprising: 
 defining a first region of said chuck moving toward said initial position,  
 defining a second region of said chuck next to said first region and moving away from said initial position,  
 defining a third region of said chuck generally opposite from said first region in relation to said chuck center and moving toward said final position, and  
 defining a fourth region of said chuck generally opposite from said second region in relation to said chuck center and moving away from said final position.  
   
   
   
       18 . The method in  claim 17 , wherein said step of moving said dispenser further comprises intersecting an axis defined by said chuck center.  
   
   
       19 . The method in  claim 18 , wherein said step of moving said dispenser further comprises moving said dispenser over said chuck center.  
   
   
       20 . A method of moving an atomizer near a chuck, comprising: 
 defining a first plane with said chuck; and    passing said atomizer through a second plane generally parallel to said first plane, 
 wherein said passing step further comprises passing said atomizer at most once generally diametrically over said chuck.  
   
   
   
       21 . The method in  claim 20 , further comprising a step of partially defining a wafer site with said chuck, wherein said wafer site extends beyond said chuck; and wherein said step of passing said atomizer comprises passing said atomizer over said wafer site.  
   
   
       22 . A method of moving an atomizer near a chuck, comprising: 
 defining a first plane with said chuck;    partially defining a wafer site with said chuck, wherein said wafer site extends beyond said chuck; and    passing said atomizer through a second plane generally parallel to said first plane, 
 wherein said passing step further comprises passing said atomizer once generally diametrically over said chuck, and wherein said step of passing said atomizer once generally diametrically over said chuck further comprises passing said atomizer over said wafer site, and wherein said step of passing said atomizer over said wafer site further comprises passing said atomizer only over said wafer site.