Control of electrolyte hydrodynamics for efficient mass transfer during electroplating

Abstract

Described are apparatus and methods for electroplating one or more metals onto a substrate. Embodiments include electroplating apparatus configured for plating highly uniform metal layers. In specific embodiments, the apparatus includes a flow-shaping element made of an ionically resistive material and having a plurality of channels made through the flow shaping element. The channels allow for transport of the electrolyte through the flow shaping element during electroplating. The channel openings are arranged in a spiral-like pattern on the substrate-facing surface of the flow shaping element such that the center of the spiral-like pattern is offset from the center of the flow shaping element.

1 . (canceled) 
     
     
         2 . A method of electroplating on a substrate comprising features having a width and/or depth of at least about 2 micrometers, the method comprising:
 (a) providing the substrate to a plating chamber, wherein the plating chamber is configured to contain an electrolyte and an anode during electroplating of metal onto the substrate, wherein the plating chamber comprises:
 (i) a substrate holder holding the substrate such that a plating face of the substrate is separated from the anode during electroplating, and 
 (ii) a flow shaping element shaped and configured to be positioned between the substrate and the anode during electroplating, the flow shaping element having a flat surface that is substantially parallel to and separated from the plating face of the substrate by a distance of about 10 millimeters or less during electroplating, wherein the flow shaping element has a plurality of holes; and 
   (b) electroplating a metal onto the substrate plating surface while rotating the substrate and while flowing the electrolyte such that a transverse flow rate of the electrolyte across the center point of the plating face of the substrate is at least about 3 cm/second, wherein flowing the electrolyte comprises diverting an electrolyte flow exiting the holes of the flow shaping element to a transverse electrolyte flow that is substantially parallel to the plating face of the substrate.   
     
     
         3 . The method of  claim 2 , wherein the electroplated metal is selected from the group consisting of copper, tin, a tin-lead composition, a tin-silver composition, nickel, a tin-copper composition, a tin-silver-copper composition, gold, and alloys thereof. 
     
     
         4 . The method of  claim 2 , wherein the average flow velocity of the electrolyte exiting the holes of the flow shaping element is at least about 10 cm/second. 
     
     
         5 . The method of  claim 2  comprising rotating the substrate at a rate of at least 30 rpm during electroplating. 
     
     
         6 . The method of  claim 2 , wherein the holes of the flow shaping element are non-communicating channels. 
     
     
         7 . The method of  claim 2 , wherein the electrolyte flows across the plating face of the substrate at a center point of the substrate at a transverse flow rate of about 5 cm/second or greater during electroplating. 
     
     
         8 . The method of  claim 2 , wherein the flow shaping element comprises an ionically resistive material selected from the group consisting of polyethylene, polypropylene, polyvinylidene diflouride (PVDF), polytetrafluoroethylene, polysulphone, and polycarbonate. 
     
     
         9 . The method of  claim 2 , wherein the flow shaping element is a disk having between about 6,000-12,000 holes. 
     
     
         10 . The method of  claim 2 , wherein the flow shaping element has a non-uniform density of holes, with a greater density of holes being present in a region of the flow shaping element that faces a rotational axis of the substrate plating face. 
     
     
         11 . The method of  claim 2 , wherein the flow shaping element is between about 5 mm and about 10 mm thick. 
     
     
         12 . The method of  claim 2 , further comprising reversing a direction of rotation of the substrate with respect to the flow shaping element during electroplating. 
     
     
         13 . The method of  claim 2 , wherein the features on the substrate are wafer level packaging features. 
     
     
         14 . The method of  claim 2 , wherein the method comprises electroplating metal in the features at a rate of at least 5 micrometers per minute. 
     
     
         15 . The method of  claim 2 , wherein the plating chamber comprises at least one electrolyte flow port, configured to increase transverse flow of electrolyte.