Tilted electrochemical plating cell with constant wafer immersion angle

Abstract

A method and apparatus for immersing a substrate for plating operations. The apparatus generally includes a plating cell configured contain a plating solution therein. The plating cell includes at least one fluid basin, a diffusion plate position in a lower portion of the at least one fluid basin, and an anode positioned below the diffusion plate, the anode and the diffusion plate being positioned in parallel orientation with each other and in a tilted orientation with respect to horizontal. The apparatus further includes a head assembly positioned proximate the plating cell, the head assembly including a base member, an actuator positioned at a distal end of the base member, and a substrate support assembly in mechanical communication with the actuator, the substrate support assembly being configured to support a substrate in the at least one fluid basin for processing in an orientation that is generally parallel to the diffusion plate.

1 . An apparatus for electrochemically plating a metal onto a substrate, comprising: 
 a plating cell configured contain a plating solution therein, the plating cell having an anode positioned therein, the anode having an upper surface that is tilted with respect to horizontal; and    a head assembly positioned proximate the plating cell and being configured to support a substrate for processing in the plating cell, the head assembly being configured to support a substrate at a tilt angle with respect to horizontal.    
     
     
         2 . The apparatus of  claim 1 , wherein a tilt angle of the anode corresponds to a tilt angle of the substrate supported by the head assembly.  
     
     
         3 . The apparatus of  claim 1 , wherein the plating cell and the head assembly are both tilted to a tilt angle, the tilt angle being between about 3° and about 35°.  
     
     
         4 . The apparatus of  claim 3 , wherein the tilt angle is between about 5° and about 30°.  
     
     
         5 . The apparatus of  claim 3 , wherein the tilt angle is between about 15° and about 30°.  
     
     
         6 . The apparatus of  claim 1 , wherein the head assembly is configured to immerse the substrate into a plating solution contained in the plating cell at a constant immersion angle.  
     
     
         7 . The apparatus of  claim 1 , wherein the plating cell comprises: 
 an inner basin configured to maintain a volume of plating solution;    an outer basin circumferentially positioned about the inner basin, the outer basin being configured to receive overflow plating solution from the inner basin;    a diffusion plate positioned in the inner basin;    an anode assembly positioned below the diffusion plate,    wherein the inner basin, outer basin, diffusion plate, and anode assembly are mounted at a tilt angle with respect to horizontal.    
     
     
         8 . The apparatus of  claim 1 , wherein the head assembly comprises: 
 a thrust plate mounted to an actuator; and    a cathode contact ring mounted to the actuator,    wherein the thrust plate and the cathode contact ring share a common axis that is mounted at a tilt angle relative to vertical.    
     
     
         9 . An electrochemical plating apparatus, comprising: 
 a plating cell configured contain a plating solution therein, the plating cell comprising: 
 at least one fluid basin;  
 a diffusion plate position in a lower portion of the at least one fluid basin; and  
 an anode positioned below the diffusion plate, the anode and the diffusion plate being positioned in parallel orientation with each other and in a tilted orientation with respect to horizontal; and  
   a head assembly positioned proximate the plating cell, the head assembly comprising: 
 a base member;  
 an actuator positioned at a distal end of the base member; and  
 a substrate support assembly in mechanical communication with the actuator, the substrate support assembly being configured to support a substrate in the at least one fluid basin for processing in an orientation that is generally parallel to the diffusion plate.  
   
     
     
         10 . The electrochemical plating apparatus of  claim 9 , wherein an upper surface of the diffusion plate and an upper surface of the anode are positioned at an angle relative to an upper surface of a fluid contained win the at least one fluid basin.  
     
     
         11 . The electrochemical plating apparatus of  claim 9 , wherein a symmetry axis of the plating cell is positioned at a tilt angle relative to horizontal of between about 3° and about 35°.  
     
     
         12 . The electrochemical plating apparatus of  claim 9 , wherein a symmetry axis of the plating cell is positioned at a tilt angle relative to horizontal of between about 5° and about 30°.  
     
     
         13 . The electrochemical plating apparatus of  claim 9 , wherein the plating cell is positioned at a tilt angle relative to horizontal of between about 15° and about 30°.  
     
     
         14 . The electrochemical plating apparatus of  claim 9 , wherein the head assembly is positioned at a tilt angle with respect to horizontal, the tilt angle being between about 3° and about 35°.  
     
     
         15 . The electrochemical plating apparatus of  claim 14 , wherein the tilt angle is between about 5° and about 30°.  
     
     
         16 . The electrochemical plating apparatus of  claim 14 , wherein the tilt angle is between about 15° and about 30°.  
     
     
         17 . The electrochemical plating apparatus of  claim 14 , wherein the head assembly is configured to immerse the substrate at a constant immersion angle relative to an upper surface of the plating solution contained in the at least one fluid basin.  
     
     
         18 . The electrochemical plating apparatus of  claim 9 , wherein the substrate support assembly comprises: 
 a contact ring in electrical communication with a cathode terminal of a power supply, the contact ring being configured to support and electrically contact a substrate an a production surface of the substrate during a plating process;    a thrust plate positioned to bias a substrate to be plated against the contact ring for plating operations; and    an actuator in mechanical communication with the contact ring and thrust plate, the actuator being configured to impart longitudinal and rotational movement to the contact ring and thrust plate.    
     
     
         19 . The electrochemical plating apparatus of  claim 9 , wherein the substrate support assembly comprises an disk shaped substrate support member having a lower substrate support surface, the lower substrate support surface including at least one vacuum channel formed therein and a plurality of electrical contact pins radially positioned proximate a perimeter of the lower surface.  
     
     
         20 . A method for immersing a substrate into an electrochemical plating solution, comprising: 
 securing a substrate to a substrate support assembly, the substrate support assembly being configured to support the substrate in a plane that is tilted at a tilt angle from horizontal; and    extending the substrate support assembly into an electroplating bath contained within an electroplating cell to immerse a production surface of the substrate, the electroplating cell being configured such that an anode is mounted at the tilt angle.    
     
     
         21 . The method of  claim 20 , wherein the substrate support assembly is configured to immerse the substrate in to the electroplating bath at a constant immersion angle relative to an upper surface of the plating bath and position the substrate substantially parallel to the anode for plating operations.  
     
     
         22 . The method of  claim 20 , further comprising maintaining the production surface of the substrate substantially parallel to the anode during the longitudinal extension of the substrate support assembly.  
     
     
         23 . The method of  claim 20 , wherein the tilt angle is between about 5° and about 35°.  
     
     
         24 . The method of  claim 20 , wherein the tilt angle is between about 15° and about 30°.  
     
     
         25 . The method of  claim 20 , wherein extending the substrate support assembly into an electroplating bath further comprises immersing the substrate into a plating solution at a constant immersion angle relative to an upper surface of the plating solution.