Methods and systems for electroplating wafers

Abstract

Improved methods and systems for electroplating wafers are described herein. The method includes the acts of introducing a wafer which is coupled to an electrode into an electroplating cell having a counter electrode; maintaining a flow of a plating solution through the cell for electroplating the wafer; removing the wafer from the cell; stopping the flow of the plating solution through the cell; maintaining a volume of plating solution within the cell sufficient to keep the counter electrode submerged during stoppage of flow; removing the plating solution within the cell; and repeating the above steps for a subsequent wafer. By stopping the flow of plating solution after completion of plating one or more wafers, a consumption rate of additives enhancing electroplating properties is reduced, a production rate of breakdown products produced during electroplating is reduced, plating solution useable life is increased, and a need for plating solution analysis is reduced.

1 . A method of electroplating wafers, comprising: 
 a. introducing a wafer coupled to an electrode into an electroplating cell having a counter electrode;    b. maintaining a flow of a plating solution through the cell for electroplating the wafer;    c. removing the wafer from the cell;    d. stopping the flow of the plating solution through the cell;    e. maintaining a volume of plating solution within the cell sufficient to keep the counter electrode submerged during stoppage of flow;    f. removing the plating solution within the cell; and    g. repeating steps a to c for electroplating a subsequent wafer.    
   
   
       2 . The method of  claim 1 , wherein the act of maintaining the flow comprises engaging a pump for a predetermined plating flow rate.  
   
   
       3 . The method of  claim 1 , wherein the act of stopping the flow comprises the further act of disengaging a pump.  
   
   
       4 . The method of  claim 1 , wherein the act of stopping the flow comprises closing a valve.  
   
   
       5 . The method of  claim 1 , wherein the act of removing the plating solution comprises releasing the plating solution into a tank.  
   
   
       6 . The method of  claim 1 , wherein the counter electrode comprises one of titanium coated with one of platinum, platinized titanium, platinized niobium, iridium oxide and ruthenium oxide.  
   
   
       7 . The method of  claim 1 , wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties.  
   
   
       8 . The method of  claim 1 , wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties, and wherein the additives comprise at least one of aromatic quaternary amines, aliphatic quaternary amines, polysulfide compounds, polyimines, polyethers, selenium, tellurium and sulfur compounds.  
   
   
       9 . The method of  claim 1 , further comprising: 
 wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties;    wherein stoppage of flow reduces a consumption rate of the additives;    wherein stoppage of flow reduces a production rate of breakdown products produced during electroplating;    wherein stoppage of flow increases plating solution useable life; and    wherein stoppage of flow reduces a need for analysis of the plating solution.    
   
   
       10 . A method of electroplating wafers, comprising: 
 for a first set of wafers to be electroplated: 
 a. introducing a wafer coupled to an electrode into an electroplating cell having a counter electrode;  
 b. maintaining a flow of a plating solution through the cell for electroplating the wafer;  
 c. removing the wafer from the cell;  
 d. repeating steps a to c for electroplating additional wafers of the first set;  
   e. stopping the flow of the plating solution through the cell after electroplating the first set of wafers;    f. maintaining a volume of plating solution within the cell sufficient to keep the counter electrode submerged during stoppage of flow;    for a subsequent set of wafers: 
 g. removing the plating solution within the cell; and  
 h. performing steps a to d for electroplating the subsequent set of wafers.  
   
   
   
       11 . The method of  claim 10 , wherein the act of maintaining the flow comprises activating a pump.  
   
   
       12 . The method of  claim 10 , wherein the act of stopping the flow comprises the further act of deactivating a pump.  
   
   
       13 . The method of  claim 10 , wherein the act of stopping the flow comprises closing a valve.  
   
   
       14 . The method of  claim 10 , wherein the act of removing the plating solution comprises releasing the plating solution into a holding tank.  
   
   
       15 . The method of  claim 10 , wherein the counter electrode comprises one of titanium coated with one of platinum, platinized titanium, platinized niobium, iridium oxide and ruthenium oxide.  
   
   
       16 . The method of  claim 10 , wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties.  
   
   
       17 . The method of  claim 10 , wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties, and wherein the additives comprise at lease one of aromatic quaternary amines, aliphatic quaternary amines, polysulfide compounds, polyimines, polyethers, selenium, tellurium and sulfur compounds.  
   
   
       18 . The method of  claim 10 , further comprising: 
 wherein the plating solution is an electrolytic solution comprising copper ions and additives for enhancing electroplating properties;    wherein stoppage of flow reduces a consumption rate of the additives;    wherein stoppage of flow reduces a production rate of breakdown products produced during electroplating;    wherein stoppage of flow increases plating solution useable life; and    wherein stoppage of flow reduces a need for analysis of the plating solution.    
   
   
       19 . A system comprising: 
 an electroplating cell for electroplating a wafer;    a positioning mechanism to introduce and remove the wafer from the cell;    a flow control mechanism to maintain a flow of plating solution through the cell for electroplating the wafer and to stop the flow thereafter;    the flow control mechanism to further maintain a volume of plating solution within the cell sufficient to keep an electrode of the cell submerged during stoppage of flow; and    the flow control mechanism to further remove the volume of plating solution from the cell prior to electroplating a subsequent wafer.    
   
   
       20 . The system of  claim 19 , wherein the positioning mechanism comprises a rotor.  
   
   
       21 . The system of  claim 19  wherein the flow control mechanism comprises a pump.  
   
   
       22 . The system of  claim 19 , wherein the flow control mechanism comprises a plating solution inlet valve to maintain and stop the flow.  
   
   
       23 . The system of  claim 19  wherein the flow control mechanism comprises a plating solution outlet valve to maintain and stop the flow.  
   
   
       24 . The system of  claim 19 , wherein the flow control mechanism comprises a plating solution drain valve.  
   
   
       25 . The system of  claim 19 , wherein the flow control mechanism comprises: 
 a pump;    a plating solution inlet valve; and    a plating solution outlet valve.    
   
   
       26 . The system of  claim 19 , wherein the flow control mechanism comprises: 
 a pump;    a plating solution inlet valve;    a plating solution outlet valve; and    a plating solution drain valve.    
   
   
       27 . The system of  claim 19 , further comprising: 
 a power supply having an anode and a cathode for coupling to the wafer, the anode comprising the electrode of the cell;    a plating solution holding tank from which the plating solution is drawn;    a plating solution inlet transport line connected to the holding tank which facilitates flow of the plating solution from the holding tank to the cell through an inlet valve of the flow control mechanism;    a pump of the flow control mechanism connected to the inlet transport line; and    a plating solution outlet transport line connected to the cell which facilitates flow of the plating solution from the cell to the holding tank through an outlet valve of the flow control mechanism.    
   
   
       28 . The system of  claim 19 , further comprising: 
 a power supply having an anode and a cathode for coupling to the wafer, the anode comprising the electrode of the cell;    a plating solution holding tank from which the plating solution is drawn;    a plating solution inlet transport line connected to the holding tank which facilitates flow of the plating solution from the holding tank to the cell through an inlet valve of the flow control mechanism;    a pump of the flow control mechanism connected to the inlet transport line;    a plating solution outlet transport line connected to the cell which facilitates flow of the plating solution from the cell to the holding tank through an outlet valve of the flow control mechanism; and    a plating solution drain transport line connected to the cell which facilitates removal of the volume of plating solution within the cell sufficient to keep the electrode of the cell submerged during stoppage of flow to a plating solution drain tank through a drain valve to remove the volume of plating solution from the cell.