Wide lipseal for electroplating

Abstract

A lipseal is designed for use in a lipseal assembly of an electroplating apparatus wherein a clamshell engages and supplies electrical current to a semiconductor substrate during electroplating. The lipseal includes an elastomeric body having an outer portion configured to engage a cup of the lipseal assembly and an inner portion configured to engage a peripheral region of the semiconductor substrate. The inner portion includes a protrusion having a width in a radial direction sufficient to provide a contact area with the semiconductor substrate which inhibits diffusion of acid in an electroplating solution used during the electroplating. The protrusion is located at an inner periphery of the lipseal.

What is claimed is: 
     
         1 . A lipseal for use in a lipseal assembly of an electroplating clamshell which engages and supplies electrical current to a semiconductor substrate during electroplating, the lipseal comprising an elastomeric body having an outer portion configured to engage a cup of the lipseal assembly and an inner portion configured to engage a peripheral region of the semiconductor substrate, the inner portion including a protrusion having a width in a radial direction sufficient to inhibit diffusion of acid in an electroplating solution used during the electroplating, the protrusion comprising an annular rim which extends completely around an inner periphery of the lipseal. 
     
     
         2 . The lipseal of  claim 1 , wherein the width is between inner and outer walls of the protrusion and the width is at least about 0.032 inch. 
     
     
         3 . The lipseal of  claim 2 , wherein the width is about 0.034 inch. 
     
     
         4 . The lipseal of  claim 1 , wherein the outer portion includes a downwardly extending rim configured to be received in a recess of the cup. 
     
     
         5 . The lipseal of  claim 1 , wherein an inner surface of the projection defines an inner diameter of the lipseal. 
     
     
         6 . A method of electroplating a semiconductor substrate using the lipseal of  claim 1 , comprising supporting a pre-wet semiconductor substrate in an electroplating clamshell such that the protrusion of the lipseal contacts an outer periphery of the semiconductor substrate, and contacting an exposed surface of the semiconductor substrate inwardly of the protrusion with an electroplating solution. 
     
     
         7 . The method of  claim 6 , wherein the projection has a width of about 0.034 inch.