Wafer electroplating apparatus for reducing edge defects

Abstract

Methods, apparatuses, and various apparatus components, such as base plates, lipseals, and contact ring assemblies are provided for reducing contamination of the contact area in the apparatuses. Contamination may happen during removal of semiconductor wafers from apparatuses after the electroplating process. In certain embodiments, a base plate with a hydrophobic coating, such as polyamide-imide (PAI) and sometimes polytetrafluoroethylene (PTFE), are used. Further, contact tips of the contact ring assembly may be positioned further away from the sealing lip of the lipseal. In certain embodiments, a portion of the contact ring assembly and/or the lipseal also include hydrophobic coatings.

1 . A contact ring for use in a cup configured to hold a semiconductor wafer during electroplating and exclude plating solution from contacting the contact ring and for supplying current to the semiconductor wafer during electroplating, the contact ring comprising:
 a unitary ring-shaped body sized and shaped to engage other components of the cup; and   a plurality of contact fingers attached to and extending inwardly from the unitary ring-shaped body and angularly disposed apart from one another, each contact finger oriented to contact the semiconductor wafer at a point less than about 1.6 mm from an outer edge of the wafer.   
     
     
         2 . The contact ring of  claim 1 , wherein the ring-shaped body and the plurality of contact fingers comprise Paliney 7. 
     
     
         3 . The contact ring of  claim 1 , wherein the plurality of contact fingers have a generally V-shape extending downwardly from a plane defined by the unitary ring-shaped body and then pointing upward to a distal point for contacting the semiconductor wafer. 
     
     
         4 . The contact ring of  claim 1 , wherein the plurality of contact fingers comprises at least about 300 contact fingers. 
     
     
         5 . The contact ring of  claim 1 , wherein the plurality of contact fingers is configured to bend under a force exerted by the semiconductor wafer during electroplating. 
     
     
         6 . The contact ring of  claim 1 , wherein at least a part of each finger in the plurality of contact fingers is coated with a hydrophobic material. 
     
     
         7 . The contact ring of  claim 6 , wherein the hydrophobic material comprises one or more hydrophobic polymers selected from the group consisting of polytetrafluroethlyene (PTFE), ethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), and copolymers thereof. 
     
     
         8 . The contact ring of  claim 6 , wherein at least a contact tip of each finger is free from the hydrophobic material. 
     
     
         9 . The contact ring of  claim 6 , wherein each contact finger is fully coated with the hydrophobic material. 
     
     
         10 . The contact ring of  claim 1 , wherein each contact finger is oriented to contact the semiconductor wafer at a point of between about 0.8 mm and 1.6 mm from an outer edge of the wafer. 
     
     
         11 . A lipseal and contact ring assembly for use in a cup configured to hold a semiconductor wafer during electroplating and exclude plating solution from a peripheral region of the semiconductor wafer and for supplying current to the semiconductor wafer during electroplating, the lipseal and contact ring assembly comprising:
 a ring-shaped elastomeric lipseal for engaging the semiconductor wafer and excluding a plating solution from the peripheral region of the semiconductor wafer, wherein the ring-shaped elastomeric lipseal has an inner diameter defining a perimeter for excluding the plating solution; and   a contact ring comprising a unitary ring-shaped body and a plurality of contact fingers attached to and extending inwardly from the ring-shaped body and angularly disposed apart from one another, each contact finger oriented to engage the semiconductor wafer at a point at least about 1.6 mm from the lipseal inner diameter.   
     
     
         12 . The lipseal and contact ring assembly of  claim 11 , wherein the contact fingers each has have a generally V-shape extending downwardly from a plane defined by the unitary ring-shaped body and then pointing upward to a distal point above a plane where the ring-shaped elastomeric lipseal engaging the semiconductor wafer. 
     
     
         13 . The lipseal and contact ring assembly of  claim 11 , wherein the ring-shaped elastomeric lipseal comprises a hydrophobic coating. 
     
     
         14 . The lipseal and contact ring assembly of  claim 13 , wherein the hydrophobic coating comprises one or more hydrophobic polymers selected from the group consisting of polytetrafluroethlyene (PTFE), ethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), and copolymers thereof. 
     
     
         15 . The lipseal and contact ring assembly of  claim 13 , wherein at least a part of each finger in the plurality of contact fingers is coated with the hydrophobic coating. 
     
     
         16 . The lipseal and contact ring assembly of  claim 15 , wherein at least a contact tip of each finger is free from the hydrophobic coating. 
     
     
         17 . The lipseal and contact ring assembly of  claim 15 , wherein each contact finger is fully coated with the hydrophobic coating. 
     
     
         18 . The lipseal and contact ring assembly of  claim 13 , wherein the ring-shaped elastomeric lipseal is at least partially coated with the hydrophobic coating. 
     
     
         19 . The lipseal and contact ring assembly of  claim 11 , wherein the ring-shaped elastomeric lipseal comprises a groove for accommodating a distribution bus. 
     
     
         20 . The lipseal and contact ring assembly of  claim 11 , wherein a portion of the ring-shaped elastomeric lipseal engaging the semiconductor wafer is configured to compress during the engagement.