Systems for electrolytic removal of metals from substrates

Abstract

A method and an apparatus for electrochemically removing a metal from a substrate surface with an electrolyte and an electrode that has a surface defining a shape suitable to cause substantially uniform removal of a metal-containing surface.

What is claimed:  
     
         1 . An apparatus for electrochemically removing a metal from a substrate surface with an electrolyte, comprising: 
 a reservoir for containing the electrolyte;    a first electrode comprising a substrate having a metal-containing surface positioned to interface with the electrolyte; and    a counter electrode in electrical contact with the first electrode;    wherein the counter electrode has a surface defining a shape suitable to cause substantially uniform removal of the metal-containing surface.    
     
     
         2 . The apparatus of  claim 1  wherein the surface of the counter electrode defines a conical shape.  
     
     
         3 . The apparatus of  claim 1  wherein the surface of the counter electrode defines a partial conical shape.  
     
     
         4 . The apparatus of  claim 1  wherein the surface of the counter electrode defines a convex shape.  
     
     
         5 . The apparatus of  claim 1  wherein the surface of the counter electrode defines two or more of the shapes suitable to cause substantially uniform removal of the metal-containing surface.  
     
     
         6 . The apparatus of  claim 5  wherein the two or more of the shapes comprise two or more concentrically arranged ridges.  
     
     
         7 . The apparatus of  claim 6  wherein the two or more concentrically arranged ridges form concentric rings.  
     
     
         8 . The apparatus of  claim 6  wherein the surface of the counter electrode defines a triangular cross-sectional shape.  
     
     
         9 . The apparatus of  claim 6  wherein the surface of the counter electrode defines a semi-circular cross-sectional shape.  
     
     
         10 . The apparatus of  claim 6  wherein the surface of the counter electrode defines a semi-parabolic shape.  
     
     
         11 . The apparatus of  claim 1  wherein the surface of the counter electrode defines a concentrically arranged continuous ridge.  
     
     
         12 . The apparatus of  claim 1  wherein the counter electrode is made of a material comprising stainless steel.  
     
     
         13 . The apparatus of  claim 1  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-11 metal and a combination thereof.  
     
     
         14 . The apparatus of  claim 13  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         15 . The apparatus of  claim 14  wherein the substrate is a silicon wafer.  
     
     
         16 . The apparatus of  claim 1  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-10 metal and a combination thereof.  
     
     
         17 . The apparatus of  claim 16  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         18 . The apparatus of  claim 17  wherein the substrate is a silicon wafer.  
     
     
         19 . The apparatus of  claim 1  further comprising a power supply to deliver alternating or pulsed bipolar electric current between the first electrode and the counter electrode.  
     
     
         20 . The apparatus of  claim 19  wherein the power supply delivers alternating current with a voltage in a range of about 1 to about 100 volts.  
     
     
         21 . The apparatus of  claim 19  wherein the power supply delivers alternating current with a current in a range of about 0.001 to about 40 Amperes.  
     
     
         22 . A method for electrochemically removing a metal from a substrate surface with an electrolyte, the method comprising: 
 providing an electrochemical cell comprising: 
 a reservoir for containing an electrolyte;  
 a first electrode comprising a substrate having a metal-containing surface positioned to interface with the electrolyte; and  
 a counter electrode in electrical contact with the first electrode,  
 wherein the counter electrode has a surface defining a shape suitable to cause substantially uniform removal of the metal-containing surface; and  
   applying an electrical current to the electrochemical cell.    
     
     
         23 . The method of  claim 22  wherein the surface of the counter electrode defines a conical shape.  
     
     
         24 . The method of  claim 22  wherein the surface of the counter electrode defines a partial conical shape.  
     
     
         25 . The method of  claim 22  wherein the surface of the counter electrode defines a convex shape.  
     
     
         26 . The method of  claim 22  wherein the surface of the counter electrode defines two or more of the shape suitable to cause substantially uniform removal of the metal-containing surface.  
     
     
         27 . The method of  claim 26  wherein the two or more of the shape comprise two or more concentrically arranged ridges.  
     
     
         28 . The method of  claim 27  wherein the two or more concentrically arranged ridges form concentric rings.  
     
     
         29 . The method of  claim 28  wherein the surface of the counter electrode defines a triangular cross-sectional shape.  
     
     
         30 . The method of  claim 28  wherein the surface of the counter electrode defines a semi-circular cross-sectional shape.  
     
     
         31 . The method of  claim 28  wherein the surface of the counter electrode defines a semi-parabolic shape.  
     
     
         32 . The method of  claim 22  wherein the surface of the counter electrode defines a concentrically arranged continuous ridge.  
     
     
         33 . The method of  claim 22  wherein the counter electrode is made of a material comprising stainless steel.  
     
     
         34 . The method of  claim 22  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-11 metal and a combination thereof.  
     
     
         35 . The method of  claim 34  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         36 . The method of  claim 35  wherein the substrate is a silicon wafer.  
     
     
         37 . The method of  claim 22  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-10 metal and a combination thereof.  
     
     
         38 . The method of  claim 37  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         39 . The method of  claim 38  wherein the substrate is a silicon wafer.  
     
     
         40 . The method of  claim 22  further comprising delivering alternating or pulsed bipolar electric current between the first electrode and the counter electrode.  
     
     
         41 . The method of  claim 40  further comprising delivering alternating current with a voltage in a range of about 1 to about 100 volts.  
     
     
         42 . The method of  claim 40  further comprising delivering alternating current with a current in a range of about 0.001 to about 40 Amperes.  
     
     
         43 . An apparatus for electrochemically removing a metal from a substrate surface with an electrolyte, comprising: 
 a reservoir for containing the electrolyte;    a first electrode comprising a substrate having a metal-containing surface positioned to interface with the electrolyte; and    a counter electrode in electrical contact with the first electrode;    wherein the counter electrode has a surface defining two or more electrically isolated areas, wherein each electrically isolated area delivers alternating or bipolar electrical current suitable to cause substantially uniform removal of the metal-containing surface.    
     
     
         44 . The apparatus of  claim 43  wherein the surface of the counter electrode defines a planar shape.  
     
     
         45 . The apparatus of  claim 44  wherein the two or more electrically isolated areas are concentrically arranged on the planar shape.  
     
     
         46 . The apparatus of  claim 45  wherein the two or more electrically isolated areas form concentric rings.  
     
     
         47 . The apparatus of  claim 44  wherein the two or more electrically isolated areas define at least one shape suitable to cause substantially uniform removal of the metal-containing surface.  
     
     
         48 . The apparatus of  claim 43  wherein a power supply delivers at least a first alternating or pulsed bipolar electric current between the first electrode and one of the two or more electrically isolated areas and a second alternating or pulsed bipolar electric current between the first electrode and another of the two or more electrically isolated areas.  
     
     
         49 . The apparatus of  claim 48  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different voltages.  
     
     
         50 . The apparatus of  claim 48  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different frequencies.  
     
     
         51 . The apparatus of  claim 48  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different waveforms.  
     
     
         52 . The apparatus of  claim 48  wherein the power supply delivers alternating current with a voltage in a range of about 1 to about 100 volts.  
     
     
         53 . The apparatus of  claim 48  wherein the power supply delivers alternating current with a current in a range of about 0.001 to about 40 Amperes.  
     
     
         54 . The apparatus of  claim 43  wherein the counter electrode is made of a material comprising stainless steel.  
     
     
         55 . The apparatus of  claim 43  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-11 metal and a combination thereof.  
     
     
         56 . The apparatus of  claim 55  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         57 . The apparatus of  claim 56  wherein the substrate is a silicon wafer.  
     
     
         58 . The apparatus of  claim 43  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-10 metal and a combination thereof.  
     
     
         59 . The apparatus of  claim 58  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         60 . The apparatus of  claim 59  wherein the substrate is a silicon wafer.  
     
     
         61 . A method for electrochemically removing a metal from a substrate surface with an electrolyte, the method comprising: 
 providing an electrochemical cell comprising: 
 a reservoir for containing an electrolyte;  
 a first electrode comprising a substrate having a metal-containing surface positioned to interface with the electrolyte; and  
 a counter electrode in electrical contact with the first electrode;  
 wherein the counter electrode has a surface defining two or more electrically isolated areas, wherein each electrically isolated area delivers alternating or bipolar electrical current suitable to cause substantially uniform removal of the metal-containing surface; and  
   applying alternating or bipolar electrical current to the electrochemical cell.    
     
     
         62 . The method of  claim 61  wherein the surface of the counter electrode defines a planar shape.  
     
     
         63 . The method of  claim 62  wherein the two or more electrically isolated areas are concentrically arranged on the planar shape.  
     
     
         64 . The method of  claim 63  wherein the two or more electrically isolated areas form concentric rings.  
     
     
         65 . The method of  claim 62  wherein the two or more electrically isolated areas define at least one shape suitable to cause substantially uniform removal of the metal-containing surface.  
     
     
         66 . The method of  claim 62  wherein a power supply delivers at least a first alternating or pulsed bipolar electric current between the first electrode and one of the two or more electrically isolated areas and a second alternating or pulsed bipolar electric current between the first electrode and another of the two or more electrically isolated areas.  
     
     
         67 . The method of  claim 67  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different voltages.  
     
     
         68 . The method of  claim 67  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different frequencies.  
     
     
         69 . The method of  claim 67  wherein the power supply delivers the first and second alternating or pulsed bipolar electric current at different waveforms.  
     
     
         70 . The method of  claim 66  wherein the power supply delivers alternating current with a voltage in a range of about 1 to about 100 volts.  
     
     
         71 . The method of  claim 66  wherein the power supply delivers alternating current with a current in a range of about 0.001 to about 40 Amperes.  
     
     
         72 . The method of  claim 61  wherein the counter electrode is made of a material comprising stainless steel.  
     
     
         73 . The method of  claim 61  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-11 metal and a combination thereof.  
     
     
         74 . The method of  claim 73  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         75 . The method of  claim 74  wherein the substrate is a silicon wafer.  
     
     
         76 . The method of  claim 61  wherein the metal-containing surface comprises a metal selected from the group consisting of a Group 8-10 metal and a combination thereof.  
     
     
         77 . The method of  claim 76  wherein the substrate is a semiconductor substrate or substrate assembly.  
     
     
         78 . The method of  claim 77  wherein the substrate is a silicon wafer.