Prevention of substrate edge plating in a fountain plating process

Abstract

A plating apparatus and method for plating a surface of a substrate are described. Generally, the apparatus includes a double wall plating vessel having an inner cup and an outer cup peripherally surrounding and spaced apart from the inner cup. The inner cup has an inlet for receiving a plating solution and an outlet from which the plating solution overflows into a plenum defined between the inner and outer cups.

1 . A plating apparatus for plating a surface of a substrate, the plating apparatus comprising:
 a plating vessel including a cup having an inlet for receiving a plating solution and an outlet from which the plating solution overflows the cup; and   a Bernoulli gripper having a planar surface with one or more gas outlets therein, the gas outlets arranged to direct a gas to flow onto an upper surface of the substrate opposite the surface to be plated, to cause the gas to flow outwardly to a peripheral edge of the substrate creating a pressure above the substrate that is less than the pressure below the substrate to hold the substrate to the planar surface, and to flow outward around substantially the entire periphery of the substrate to substantially prevent any plating occurring on the upper surface or a peripheral edge of the substrate when the substrate is held in a predetermined position proximal to the outlet of the cup so that the plating solution flowing from the outlet passes over and plates the surface of the substrate.   
     
     
         2 . An apparatus according to  claim 1 , wherein the planar surface further comprises a recess in which the substrate is held, and wherein the recess comprises interior side surfaces that peripherally surround and serve to center the substrate on the planar surface. 
     
     
         3 . An apparatus according to  claim 1 , wherein the Bernoulli gripper further comprises a plurality of additional gas outlets located near the peripheral edge of the substrate to provide a flow of gas across the peripheral edge to substantially prevent any plating occurring thereon. 
     
     
         4 . An apparatus according to  claim 1 , wherein the plating vessel is a double wall plating vessel, and the cup is an inner cup of the double wall plating vessel. 
     
     
         5 . An apparatus according to  claim 4 , further comprising:
 a plenum defined between the inner cup and an outer cup of the double wall plating vessel, wherein the plating solution overflows from the outlet of the inner cup and into the plenum.   
     
     
         6 . An apparatus according to  claim 5 , further comprising:
 a plurality of outlets located and oriented to direct streams of gas into the plenum, redirecting plating solution away from the edge of the substrate.   
     
     
         7 . An apparatus according to  claim 4 , wherein the apparatus is an electroplating apparatus and further comprises an electrical power supply having a first terminal electrically coupled to an electrode positioned within the plating solution in the inner cup and a second terminal electrically coupled to the substrate. 
     
     
         8 . An apparatus according to  claim 1 , wherein the plating vessel is a single wall plating vessel. 
     
     
         9 . An apparatus according to  claim 1 , wherein the Bernoulli gripper is adaptable to hold the substrate without physically contacting the substrate. 
     
     
         10 . A plating apparatus for plating a surface of a substrate, the plating apparatus comprising:
 a double wall plating vessel including an inner cup, an outer cup and a plenum defined between the inner cup and the outer cup, the inner cup having an inlet for receiving a plating solution and an outlet from which the plating solution overflows the inner cup into the plenum;   a Bernoulli gripper having a planar surface with one or more gas outlets therein, the gas outlets arranged to direct a gas to flow onto an upper surface of the substrate opposite the surface to be plated, to cause the gas to flow outwardly to a peripheral edge of the substrate creating a pressure above the substrate that is less than the pressure below the substrate to hold the substrate to the planar surface, and to flow outward around substantially the entire periphery of the substrate to substantially prevent any plating occurring on the upper surface or a peripheral edge of the substrate when the substrate is held in a predetermined position proximal to the outlet of the inner cup so that the plating solution flowing from the outlet passes over and plates the surface of the substrate; and   a plurality of outlets located and oriented to direct streams of gas into the plenum, redirecting plating solution away from the edge of the substrate.   
     
     
         11 . An apparatus according to  claim 10 , wherein the planar surface further comprises a recess in which the substrate is held, and wherein the recess comprises interior side surfaces that peripherally surround and serve to center the substrate on the planar surface. 
     
     
         12 . An apparatus according to  claim 10 , wherein the Bernoulli gripper further comprises a plurality of additional gas outlets located near the peripheral edge of the substrate to provide a flow of gas across the peripheral edge to substantially prevent any plating occurring thereon. 
     
     
         13 . An apparatus according to  claim 10 , wherein the apparatus is an electroplating apparatus and further comprises an electrical power supply having a first terminal electrically coupled to an electrode positioned within the plating solution in the inner cup and a second terminal electrically coupled to the substrate. 
     
     
         14 . An apparatus according to  claim 10 , wherein the Bernoulli gripper is adaptable to hold the substrate without physically contacting the substrate. 
     
     
         15 . A plating apparatus for plating a surface of a substrate, the plating apparatus comprising:
 a double wall plating vessel including an inner cup, an outer cup and a plenum defined between the inner cup and the outer cup, the inner cup having an inlet for receiving a plating solution and an outlet from which the plating solution overflows the inner cup into the plenum;   a Bernoulli gripper having a planar surface with one or more gas outlets therein, the gas outlets arranged to direct a gas to flow onto an upper surface of the substrate opposite the surface to be plated when the substrate is held in a predetermined position proximal to the outlet of the inner cup; and   a plurality of outlets located and oriented to direct streams of gas into the plenum.   
     
     
         16 . An apparatus according to  claim 15 , wherein the planar surface further comprises a recess in which the substrate is held, and wherein the recess comprises interior side surfaces that peripherally surround and serve to center the substrate on the planar surface. 
     
     
         17 . An apparatus according to  claim 15 , wherein the Bernoulli gripper further comprises a plurality of additional gas ports located near the peripheral edge of the substrate. 
     
     
         18 . An apparatus according to  claim 15 , wherein the apparatus is an electroplating apparatus and further comprises an electrical power supply having a first terminal electrically coupled to an electrode positioned within the plating solution in the inner cup and a second terminal electrically coupled to the substrate. 
     
     
         19 . An apparatus according to  claim 15 , wherein the Bernoulli gripper is adaptable to hold the substrate without physically contacting the substrate. 
     
     
         20 . An apparatus according to  claim 15 , further comprising:
 flexible electrical conductors adapted to electrically couple to the substrate when the substrate is held in the predetermined position.