In-situ cleaning processes for semiconductor electroplating electrodes

Abstract

Methods and apparatuses for in-situ cleaning of semiconductor electroplating electrodes to remove plating metal without requiring the manual removal of the electrodes from the semiconductor plating equipment. The electrode is placed into the plating liquid and an electrical current having reverse polarity is passed between the electrode and plating liquid. Plating deposits which have accumulated on the electrode are electrochemically dissolved and removed from the electrode.

We claim  
     
         1 . A method for in-situ cleaning a semiconductor electroplating electrode to remove at least one plating metal from the surface of the electrode, said electrode being used to conduct current between a semiconductor workpiece and an electroplating electrical power supply, comprising: 
 placing the electrode into a plating liquid;    passing a reverse current between the electrode and said plating liquid using reverse polarity which causes metal previously plated onto the electrode to electrochemically disperse into the plating liquid.    
     
     
         2 . A method according to  claim 1  and further comprising rotating the electrode during performance of said passing a reverse current.  
     
     
         3 . A method according to  claim 1  and further comprising rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current.  
     
     
         4 . A method according to  claim 1  and further comprising rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current.  
     
     
         5 . A method according to  claim 1  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         6 . A method according to  claim 1  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         7 . A method according to  claim 1  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         8 . A method according to  claim 1  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         9 . A method according to  claim 1  wherein the reverse current is provided using the electroplating electrical power supply.  
     
     
         10 . A method according to  claim 1  wherein the reverse current is provided using at least one auxiliary electrode.  
     
     
         11 . A method according to  claim 1  wherein the reverse current is provided using at least one auxiliary electrode which is in electrical contact with the plating liquid during a cleaning cycle and is switched out of operation during a normal operating cycle.  
     
     
         12 . A method according to  claim 1  wherein the reverse current is provided at a voltage potential in the appoximate range of 0.1-100 volts between the electrode and the plating liquid.  
     
     
         13 . A method according to  claim 1  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid.  
     
     
         14 . A method according to  claim 1  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid, said voltage potential varying dependent on the number of semiconductor workpieces are processed through a normal operating cycle.  
     
     
         15 . A method for in-situ cleaning a semiconductor electroplating electrode to remove at least one plating metal from the surface of the electrode, said electrode being used to conduct current between a semiconductor workpiece and an electroplating electrical power supply to facilitate plating of the at least one plating metal onto the semiconductor workpiece, said electroplating electrical power supply applying electrical current to said electrode using a first polarity, comprising: 
 removing any semiconductor workpiece from a semiconductor workpiece support which includes the electrode as part thereof;    placing the electrode into a plating liquid;    passing a reverse electrical current between the electrode and said plating liquid using a second polarity which has a reverse polarity to said first polarity, said passing current causing the metal plated onto the electrode to be dissolved into the plating liquid.    
     
     
         16 . A method according to  claim 15  and further comprising rotating the electrode during performance of said passing a reverse current.  
     
     
         17 . A method according to  claim 15  and further comprising rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current.  
     
     
         18 . A method according to  claim 15  and further comprising rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current.  
     
     
         19 . A method according to  claim 15  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         20 . A method according to  claim 15  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         21 . A method according to  claim 15  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         22 . A method according to  claim 15  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         23 . A method according to  claim 15  wherein the reverse current is provided using the electroplating electrical power supply.  
     
     
         24 . A method according to  claim 15  wherein the reverse current is provided using at least one auxiliary electrode.  
     
     
         25 . A method according to  claim 15  wherein the reverse current is provided using at least one auxiliary electrode which is in electrical contact with the plating liquid during a cleaning cycle and is switched out of operation during a normal operating cycle.  
     
     
         26 . A method according to  claim 15  wherein the reverse current is provided at a voltage potential in the appoximate range of 0.1-100 volts between the electrode and the plating liquid.  
     
     
         27 . A method according to  claim 15  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid.  
     
     
         28 . A method according to  claim 15  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid, said voltage potential varying dependent on the number of semiconductor workpieces are processed through a normal operating cycle.  
     
     
         29 . A method according to  claim 15  wherein the reverse current is provided by applying the electroplating electrical power supply to the electrode and plating liquid in said reverse polarity.  
     
     
         30 . A method for operating a semiconductor electroplating apparatus, comprising: 
 placing a semiconductor workpiece in a workpiece support, said workpiece support including at least one electrode which contacts the semiconductor workpiece to conduct electrical current therebetween;    placing at least one surface of the semiconductor workpiece into a plating liquid;    electroplating at least one plating metal onto said at least one surface of the semiconductor workpiece during a normal operating cycle, said electroplating including charging a plating liquid and the semiconductor workpiece to differing voltages which have a first polarity relationship;    removing any semiconductor workpiece from the semiconductor workpiece support;    placing the at least one electrode into the plating liquid;    passing a reverse electrical current between the electrode and said plating liquid using a second polarity which has a reverse polarity to said first polarity, said passing current causing metal plated onto the at least one electrode to electrochemically disperse into the plating liquid.    
     
     
         31 . A method according to  claim 30  and further comprising rotating the electrode during performance of said passing a reverse current.  
     
     
         32 . A method according to  claim 30  and further comprising rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current.  
     
     
         33 . A method according to  claim 30  and further comprising rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current.  
     
     
         34 . A method according to  claim 30  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 1 revolution per minute to about 300 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         35 . A method according to  claim 30  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating at least once during a cleaning cycle.  
 
     
     
         36 . A method according to  claim 30  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         37 . A method according to  claim 30  and further comprising: 
 rotating the electrode at an angular velocity in the approximate range from about 10 revolutions per minute to about 100 revolutions per minute during performance of said passing a reverse current;  
 changing the direction of said rotating in the approximate range from about every 10 seconds to about every 1 minute.  
 
     
     
         38 . A method according to  claim 30  wherein the reverse current is provided using the electroplating electrical power supply.  
     
     
         39 . A method according to  claim 30  wherein the reverse current is provided using at least one auxiliary electrode.  
     
     
         40 . A method according to  claim 30  wherein the reverse current is provided using at least one auxiliary electrode which is in electrical contact with the plating liquid during a cleaning cycle and is switched out of operation during a normal operating cycle.  
     
     
         41 . A method according to  claim 30  wherein the reverse current is provided at a voltage potential in the appoximate range of 0.1-100 volts between the electrode and the plating liquid.  
     
     
         42 . A method according to  claim 30  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid.  
     
     
         43 . A method according to  claim 30  wherein the reverse current is provided at a voltage potential in the appoximate range of 1-10 volts between the electrode and the plating liquid, said voltage potential varying dependent on the number of semiconductor workpieces are processed through a normal operating cycle.  
     
     
         44 . A semiconductor processing station for use in electroplating a metal onto a semiconductor workpiece, comprising: 
 a workpiece support mounted to support a semiconductor workpiece, said workpiece support being capable of holding at least one processed surface of the workpiece in position for contact with a plating liquid;    a plating liquid receptacle in which plating liquid is held;    at least one electrode which is electrically conductive and capable of contacting a semiconductor workpiece held in the workpiece support to conduct electrical current between the at least one electrode and the semiconductor workpiece;    an electroplating power supply for generating a plating current used during a normal operating cycle to electrochemically plate metal onto at least one surface of the semiconductor workpiece using a first voltage difference between the plating liquid and said at least one electrode, said first voltage difference having a first polarity;    a reverse polarity electrical power supply connected to apply electrical current to the at least one electrode and said plating liquid during a cleaning cycle so as to produce a second voltage difference therebetween which is of a second polarity, said second polarity having a reverse polarity relationship compared to said first polarity.    
     
     
         45 . A semiconductor processing station according to  claim 44  wherein the reverse polarity electrical power supply includes an auxiliary electrode which is in electrically conductive relationship to the plating liquid.  
     
     
         46 . A semiconductor processing station according to  claim 44  wherein the workpiece support is capable of rotating the semiconductor workpiece and the at least one electrode, to allow the rotating of the semiconductor workpiece during said normal operating cycle, and to allow the rotating of said at least one electrode in the plating liquid during said cleaning cycle.  
     
     
         47 . A semiconductor processing station for use in electroplating a metal onto a semiconductor workpiece, comprising: 
 a workpiece support mounted to support a semiconductor workpiece, said workpiece support being capable of holding at least one processed surface of the workpiece in position for contact with a plating liquid;    at least one electrode which is electrically conductive and capable of contacting a semiconductor workpiece held in the workpiece support to conduct electrical current between the at least one electrode and the semiconductor workpiece;    an electroplating power supply for generating a plating current used during a normal operating cycle to electrochemically plate metal onto at least one surface of the semiconductor workpiece using a first voltage difference between the plating liquid and said at least one electrode, said first voltage difference having a first polarity;    means for applying electrical current to the at least one electrode and said plating liquid having a second voltage difference which is of a second polarity, said second polarity having a reverse polarity relationship compared to said first polarity.    
     
     
         48 . A semiconductor processing station according to  claim 47  wherein the reverse polarity electrical power supply includes an auxiliary if electrode which is in electrically conductive relationship to the plating liquid.