Apparatus and method for electrochemically processing a microelectronic workpiece

Abstract

A reactor for use in electrochemical processing of a microelectronic workpiece is set forth and described herein. The apparatus comprises one or more walls defining a processing space therebetween for containing a processing fluid The processing space includes at least a first fluid flow region and a second fluid flow region A first electrode is disposed in the processing fluid of the first fluid flow region while a second electrode, comprising at least a portion of the microelectronic workpiece, is disposed in the processing fluid of the second fluid flow region. Fluid flow within the first fluid flow region is generally directed toward the first electrode and away from the second electrode while fluid flow within the second fluid flow region is generally directed toward the second electrode and away from the first electrode Depending on the particular electrochemical process that is to be executed, the first electrode may constitute either an anode or a cathode in the electrochemical processing of the microelectronic workpiece The foregoing reactor architecture is particularly useful in connection with electroplating of the microelectronic workpiece and, more particularly, in electroplating operations that employ a consumable anode, such as a phosphorized copper anode.

What is claimed is:  
     
         1 . A reactor for use in electrochemical processing of a microelectronic workpiece, the apparatus comprising. 
 one or more walls defining a processing space therebetween for containing a processing fluid;    a first fluid flow region in the processing space;    a first electrode disposed in the processing fluid of the first fluid flow region;    a second fluid flow region in the processing space,    a second electrode disposed in the processing fluid of the second fluid flow region, the second electrode comprisingt at least a portion of the microelectronic workpiece, fluid flow within the first fluid flow region being generally directed toward the first electrode and away from the second electrode, fluid flow within the second fluid flow region being generally directed toward the second electrode and away from the first electrode.    
     
     
         2 . A reactor as claimed in  claim 1  wherein the first electrode comprises an anode in the electrochemical processing of the microelectronic workpiece.  
     
     
         3 . A reactor as claimed in  claim 1  wherein the first electrode comprises a cathode in the electrochemical processing of the microelectronic workpiece.  
     
     
         4 . A reactor as claimed in  claim 1  wherein a single fluid inlet provides processing fluid to both the first and second fluid flow regions  
     
     
         5 . A reactor as claimed in  claim 1  and further comprising at least one pressure drop member disposed in the processing fluid of the processing space in an intermediate position between the first and second fluid flow regions.  
     
     
         6 . A reactor as claimed in  claim 1  wherein the first fluid flow region is adjacent the second fluid flow region  
     
     
         7 . A reactor as claimed in  claim 5  wherein the first fluid flow region is adjacent the second fluid flow region  
     
     
         8 . A reactor for electrochemically processing a microelectronic workpiece comprising 
 one or more walls defining a processing space therebetween for containing a processing fluid,    a microelectronic workpiece support including one or more conductive members disposed to electrically contact the microelectronic workpiece to provide electrical power for electrochemical processing of the microelectronic workplace, the microelectronic workpiece support being disposed to bring at least one portion of the microelectronic workpiece into contact with the processing fluid,    at least one electrode disposed in contact with the processing fluid in the processing space, the at least one electrode being spaced from the microelectronic workpiece and positioned to provide electrical power for electrochemical processing of the microelectronic workpiece,    at least one processing fluid inlet disposed to provide a flow of the processing fluid into the processing space,    at least one processing fluid outlet disposed to provide a flow of the processing fluid from the processing space, the at least one processing fluid outlet being positioned within the processing space to direct at least a portion of the flow of the processing fluid about the at least one electrode and away from the microelectronic workpiece as the flow exits from the processing space.    
     
     
         9 . A reactor as claimed in  claim 8  wherein the at least one electrode comprises an anode in the electrochemical processing of the microelectronic workpiece.  
     
     
         10 . A reactor as claimed in  claim 8  wherein the at least one electrode comprises a cathode in the electrochemical processing of the microelectronic workpiece.  
     
     
         11 . A reactor is claimed in  claim 8  and further comprising at least one permeable membrane disposed between the microelectronic workpiece support and the at least one electrode  
     
     
         12 . A reactor as claimed in  claim 1  wherein the at least one permeable membrane is disposed between a first fluid flow region of the processing space and a second fluid flow region of the processing space  
     
     
         13 . A reactor as claimed in  claim 12  wherein the at least one processing fluid inlet is disposed in the first fluid flow region.  
     
     
         14 . A reactor as claimed in  claim 13  wherein the at least one processing fluid outlet is disposed in the second fluid flow region.  
     
     
         15 . A reactor as claimed in  claim 12  wherein the at least one processing fluid outlet is disposed in the second fluid flow region  
     
     
         16 . A reactor as claimed in  claim 15  and further comprising a further processing fluid outlet disposed in the second fluid flow region proximate the microelectronic workpiece  
     
     
         17 . A reactor as claimed in  claim 8  and further comprising a further processing fluid outlet disposed proximate the microelectronic workpiece  
     
     
         18  A reactor as claimed in  claim 12  wherein the first and second fluid flow regions are adjacent one another  
     
     
         19 . A reactor as claimed in  claim 8  and further comprising 
 a cup disposed in the processing space, the cup assembly including an open end that opens toward the microelectronic workpiece,  
 a pressure drop member disposed over the open end of the cup, the at least one electrode being disposed in an interior chamber defined by at least the cup and the pressure drop member.  
 
     
     
         20 . A reactor as claimed in  claim 19  wherein the pressure drop member comprises a permeable membrane having a conical shape with an apex directed toward the interior chamber  
     
     
         21 . A reactor as claimed in  claim 19  wherein the at least one processing fluid outlet is disposed to exhaust processing fluid from the interior chamber.  
     
     
         22 . A reactor as claimed in  claim 8  wherein the one or more walls defining the processing space form a cup having an open upper end  
     
     
         23 . A reactor as claimed in  claim 22  and further comprising a head assembly including the microelectronic workpiece support, the head assembly being movable with respect to the open upper end of the cup between a workpiece loading position and a workpiece processing position  
     
     
         24 . A reactor is claimed in  claim 8  wherein the microelectronic workpiece support is rotatable to facilitate rotation of the microelectronic workpiece during electrochemical processing thereof  
     
     
         25 . A reactor is claimed in  claim 23  wherein the head assembly comprises a rotor motor that is connected to the microelectronic workpiece support to rotate the microelectronic workpiece during electrochemical processing thereof  
     
     
         26 . A reactor for electrochemically processing a microelectronic workpiece comprising 
 one or more walls defining a processing space for containing a processing fluid, the one or more walls forming a processing cup having an open top;    a microelectronic workpiece support including one or more conductive members disposed to electrically contact the microelectronic workpiece to provide electrical power for electrochemical processing of the microelectronic workpiece, the microelectronic workpiece support being disposed proximate the open top of the processing cup to bring at least one portion of the microelectronic workpiece into contact with the processing fluid for electrochemical processing,    an electrode housing disposed in the processing cup and having an end that opens toward the microelectronic workpiece support,    a pressure drop member disposed over the open end of the electrode housing,    at least one electrode disposed in an interior region of the electrode housing;    at least one processing fluid inlet disposed exterior to the interior region of the electrode housing to provide a flow of the processing fluid into the processing space;    at least one processing fluid outlet in fluid communication with the interior region of the electrode housing to generate a flow of the processing fluid through the pressure drop member and into the interior region of the electrode housing.    
     
     
         27 . A reactor as claimed in  claim 26  wherein the at least one electrode comprises an anode in the electrochemical processing of the microelectronic workpiece.  
     
     
         28 . A reactor as claimed in  claim 26  wherein the at least one electrode comprises a cathode in the electrochemical processing of the microelectronic workpiece.  
     
     
         29 . A reactor as claimed in  claim 26  wherein the at least one processing fluid outlet draws at least a portion of the flow of the processing fluid about the at least one electrode as the processing fluid exits from the interior region.  
     
     
         30 . A reactor as claimed in  claim 26  wherein at least a portion of the processing fluid entering the processing space exits from the processing space through the open top of the processing cup  
     
     
         31 . A reactor as claimed in  claim 26  wherein the pressure drop member comprises a permeable membrane  
     
     
         32 . A reactor as claimed in  claim 31  wherein the permeable membrane is conical in shape having an apex directed toward the interior region of the electrode housing  
     
     
         33 . A reactor as claimed in  claim 26  wherein the pressure drop member is conical in shape having an apex directed toward the interior region of the electrode housing  
     
     
         34 . An apparatus for use in a reactor assembly used in electrochemical processing of a microelectronic workpiece, the apparatus comprising: 
 one or more walls defining a processing space therebetween for containing a processing fluid,    a pressure drop member disposed in the processing space to divide the processing space into at least a first fluid flow region and a second fluid flow region, the pressure drop member tacilitating, veneration of a pressure drop thereacross, fluid flow during electrochemical processing of the microelectronic workpiece being from the second region into the first region across the pressure drop member,    a microelectronic workpiece disposed for contact with processing fluid in the second fluid flow region, and    an electrode located in the first region of the processing space    
     
     
         35 . A reactor as claimed in  claim 34  wherein the at least one electrode comprises an anode in the electrochemical processing of the microelectronic workpiece  
     
     
         36 . A reactor as claimed in  claim 34  wherein the at least one electrode comprises a cathode in the electrochemical processing of the microelectronic workpiece  
     
     
         37 . An apparatus as claimed in  claim 34  wherein the pressure drop member comprises a permeable membrane  
     
     
         38 . An apparatus as claimed in  claim 34  wherein the first and second fluid flow regions are adjacent one another  
     
     
         39 . An apparatus for electrochemically processing a microelectronic workpiece comprising 
 means for containing a processing fluid to form a processing space,    means for providing electrical contact to one or more surfaces of the microelectronic workpiece to supply electrical power for electrochemical processing of the workpiece,    electrode means for supplying electrical power for electrochemical processing of the microelectronic workpiece,    means for providing a first fluid flow region and a second fluid flow region within the processing space, the electrode means being disposed in the first fluid flow region, the means for providing electrical contact being disposed in the second fluid flow region, processing fluid flow within the first fluid flow region being generally directed toward the electrode means and generally away from the means for providing electrical contact, processing fluid flow within the second fluid flow region being generally directed toward one or more surfaces of a microelectronic workipiece contacted by the means for providing electrical contact and generally away from the electrode means    
     
     
         40 . An apparatus as claimed in  claim 39  wherein the at least one electrode comprises an anode in the electrochemical processing of the microelectronic workpiece  
     
     
         41  An apparatus as claimed in  claim 39  wherein the at least one electrode comprises a cathode in the electrochemical processing of the microelectronic workpiece  
     
     
         42 . A method for electrochemically processing a microelectronic workpiece comprising the steps of 
 dividing a processing space containing processing fluid into at least a first fluid flow region and a second fluid flow region,    locating a first electrode within the processing, fluid of the first fluid flow region, locating a second electrode comprising at least a portion of the microelectronic workpiece within the processing fluid of the second fluid flow region;    generating a fluid flow of the processing, fluid within the first fluid flow region that is generally directed toward the first electrode and generally away from the second electrode, and    generating a fluid flow of the processing fluid within the second fluid flow region that is generally directed toward the second electrode and generally away from the first electrode    
     
     
         43 . A method as claimed in  claim 42  and further comprising the step of providing a negative potential to the first electrode with respect to the second electrode.  
     
     
         44 . A method as claimed in  claim 42  and further comprising the step of providing a negative potential to the second electrode with respect to the first electrode.  
     
     
         45 . A method as claimed in  claim 42  wherein the step of generating the fluid flow of the processing fluid within the second fluid flow region comprises the step of supplying processing fluid from a fluid reservoir into the second fluid flow region of the processing space  
     
     
         46 . A method as claimed in  claim 42  wherein the step of generating the fluid flow of the processing fluid within the first fluid flow region comprises the step of exhausting at least a portion of the processing fluid from the first fluid flow region away from the processing space  
     
     
         47 . A method as claimed in  claim 42  and further comprising the step of limiting the flow of processing fluid from the second fluid flow region into the first fluid flow region, thereby maintaining a pressure differential between the first fluid flow region and the second fluid flow region  
     
     
         48 . A method as claimed in  claim 47  wherein the step of limiting the flow comprises the step of providing a permeable membrane between the first fluid flow region and the second fluid flow region  
     
     
         49 . An apparatus for use in electrochemical processing of a microelectronic workpiece comprising 
 a processing space containing processing fluid,    at least one fluid inlet disposed to provide a flow of processing fluid to the processing space,    an electrode assembly disposed in the processing space comprising    an electrode housing having an open end,    a pressure drop member disposed over the open end of the electrode housing, the electrode housing and pressure drop member defining an interior electrode chamber,    an electrode disposed in the interior electrode chamber,    at least one fluid outlet in fluid communication with the interior electrode chamber to thereby draw a flow of processing fluid through the pressure drop member and into the interior electrode chamber.    
     
     
         50 . An apparatus as claimed in  claim 49  wherein the pressure drop member comprises a permeable membrane.  
     
     
         51 . An apparatus as claimed in claim  50  and further comprising a membrane frame disposed over the open end of the electrode housing, the permeable membrane being connected to the membrane frame  
     
     
         52 . An apparatus as claimed in  claim 49  wherein the pressure drop member has a conical shape with an apex directed toward the interior electrode chamber.