Deposition of viscous material

Abstract

Embodiments of the invention provide methods and systems for depositing a viscous material on a substrate surface. In one embodiment, the invention provides a method of depositing a viscous material on a substrate surface, the method comprising: applying a pre-wet material to a surface of a substrate; depositing a viscous material atop the pre-wet material; rotating the substrate about an axis to spread the viscous material along the surface of the substrate toward a substrate edge; and depositing additional pre-wet material in a path along the surface and adjacent the spreading viscous material.

1 . A system for depositing a viscous material on a semiconductor wafer, the system comprising:
 an applicator that applies a pre-wet material to a surface of the semiconductor wafer;   a deposition system that deposits a viscous material atop the pre-wet material;   a rotation system that rotates the semiconductor wafer about an axis; and   an applicator that periodically, deposits additional pre-wet material in a path along the surface of the semiconductor wafer to continuously maintain a pre-wet pool adjacent the spreading viscous material.   
     
     
         2 . The system of  claim 1 , wherein the rotation system is operable to rotate the semiconductor wafer about the axis at between about 3000 rpm and about 4000 rpm. 
     
     
         3 . (canceled) 
     
     
         4 . The system of  claim 1 , wherein the applicator that periodically deposits additional pre-wet material periodically deposits the additional pre-wet material in a substantially radial path along the surface extending to an edge of the semiconductor wafer. 
     
     
         5 . The system of  claim 1 , wherein the path is a substantially radial path. 
     
     
         6 . The system of  claim 1 , wherein the applicator that applies the pre-wet material and the applicator that periodically deposits additional pre-wet material are the same applicator. 
     
     
         7 . A system for depositing a viscous material on a semiconductor wafer, the system comprising:
 an applicator that applies a pre-wet material to a surface of the semiconductor wafer;   a deposition system that deposits a viscous material atop the pre-wet material;   a rotation system that rotates the semiconductor wafer about an axis; and   an applicator that continuously deposits additional pre-wet material in a path along the surface to continuously maintain a pre-wet pool adjacent the spreading viscous material.   
     
     
         8 . The system of  claim 7 , wherein the rotation system is operable to rotate the semiconductor wafer about the axis at between about 3000 rpm and about 4000 rpm. 
     
     
         9 . The system of  claim 7 , wherein the path is a substantially radial path. 
     
     
         10 . The system of  claim 7 , wherein the path extends to an edge of the semiconductor wafer. 
     
     
         11 . The system of  claim 7 , wherein the applicator that continuously deposits additional pre-wet material deposits the additional pre-wet material in a substantially radial path along the surface extending to an edge of the semiconductor wafer. 
     
     
         12 . The system of  claim 7 , wherein the applicator that applies the pre-wet material and the applicator that continuously deposits additional pre-wet material are the same applicator.