Electroplating apparatuses and methods employing liquid particle counter modules

Abstract

Disclosed herein are electroplating apparatuses for electroplating metal onto a semiconductor wafer which may include an electroplating cell, an electrolyte circulation system connected to the cell for circulating electrolyte to and from the cell, first and second sampling ports for taking first and second sample of electrolyte at first and second locations in the apparatus, and one or more liquid particle counter modules, connected to the first and second sampling ports, for measuring particle concentration in the electrolyte. Also disclosed herein are methods for reducing particle concentration in an electrolyte present in an electroplating apparatus which may include determining an approximate particle concentration using a liquid particle counter module and modifying the operation of the electroplating apparatus to reduce particle concentration in the electrolyte.

We claim: 
     
         1 . An electroplating apparatus for electroplating metal onto a semiconductor wafer, the apparatus comprising:
 an electroplating cell for containing an anode and an electrolyte during electroplating;   an electrolyte circulation system connected to the cell for circulating electrolyte to and from the cell;   a first sampling port for taking a first sample of electrolyte at a first location in the apparatus;   a second sampling port for taking a second sample of electrolyte at a second location in the apparatus;   one or more liquid particle counter modules for measuring particle concentration in the electrolyte, the liquid particle counter modules connected to the first sampling port and the second sampling port.   
     
     
         2 . The apparatus of  claim 1 , further comprising a manifold, the manifold connected to at least two sampling ports and to at least one liquid particle counter module. 
     
     
         3 . The apparatus of  claim 2 , further comprising two or more valves for controlling the flow of electrolyte from the at least two sampling ports to the manifold. 
     
     
         4 . The apparatus of  claim 3 , further comprising a controller, the controller comprising machine readable instructions for controlling the opening and closing of the two or more valves to control the flow of electrolyte from the at least two sampling ports to the manifold. 
     
     
         5 . The apparatus of  claim 1 , wherein at least one liquid particle counter module is configured to measure particle concentration in the electrolyte at a rate between about 9 and 11 mL/min. 
     
     
         6 . The apparatus of  claim 1 , further comprising a pump, and wherein a sampling port is located directly downstream of the pump, and wherein a sampling port is located directly upstream of the pump. 
     
     
         7 . The apparatus of  claim 6 , further comprising a controller configured to (i) monitor the particle concentrations upstream and downstream from the pump, (ii) determine when the pump is producing more than a threshold amount of particles; and (iii) generate an alert and/or modify operation of the apparatus when the pump is producing more than the threshold amount of particles. 
     
     
         8 . The apparatus of  claim 1 , further comprising a reservoir for holding electrolyte, and wherein a sampling port is located within the reservoir. 
     
     
         9 . The apparatus of  claim 1 , further comprising a contactor, and wherein a sampling port is located directly downstream of the contactor. 
     
     
         10 . The apparatus of  claim 1 , further comprising a particle filter, and wherein a sampling port is located directly downstream of the particle filter. 
     
     
         11 . The apparatus of  claim 1 , wherein a sampling port is located directly upstream of the electroplating cell. 
     
     
         12 . The apparatus of  claim 1 , wherein a sampling port is located directly upstream of the electroplating cell and a sampling port is located directly downstream of the electroplating cell. 
     
     
         13 . The apparatus of  claim 1 , wherein a sampling port is located within the interior of the electroplating cell. 
     
     
         14 . The apparatus of  claim 13 , further comprising a separated anode chamber within the electroplating cell, and wherein a sampling port is located proximate to, and downstream from, a membrane separating the separated anode chamber from the cathode chamber within the electroplating cell. 
     
     
         15 . The apparatus of  claim 13 , further comprising a controller configured to (i) monitor the particle concentration within the interior of the electroplating cell, (ii) determine when the particle concentration in the electroplating cell is greater than a threshold level; and (iii) generate an alert and/or modify operation of the apparatus when the particle concentration in the electroplating cell is greater than the threshold level. 
     
     
         16 . The electroplating apparatus of  claim 1 , further comprising a controller configured to:
 determine the approximate particle concentration in the first sample using the one or more liquid particle counter modules;   determine the approximate particle concentration in the second sample using the one or more liquid particle counter modules; and   modify the operation of the electroplating apparatus to reduce particle concentration in the electrolyte circulating to and from the electroplating cell.   
     
     
         17 . The electroplating apparatus of  claim 16 , wherein the controller is further configured to identify a source of particle contamination in the apparatus based on the approximate particle concentrations in the first and second samples, and wherein modifying the operation of the electroplating apparatus comprises diverting electrolyte away from the source of particle contamination. 
     
     
         18 . The electroplating apparatus of  claim 17 , wherein the source of particle contamination is another electroplating cell of the electroplating apparatus, and wherein diverting electrolyte away from this cell comprises closing one or more valves to isolate this cell from the electrolyte circulation system. 
     
     
         19 . The electroplating apparatus of  claim 16 , wherein the controller is further configured to:
 direct the first sample of electrolyte from the first sampling port to the one or more liquid particle counter modules; and   direct the second sample of electrolyte from the second sampling port to the one or more liquid particle counter modules.   
     
     
         20 . The electroplating apparatus of  claim 1 , further comprising a controller configured to:
 determine the approximate particle concentration in the first sample using the one or more liquid particle counter modules;   determine the approximate particle concentration in the second sample using the one or more liquid particle counter modules; and   send an alert to the operator of the electroplating apparatus if the approximate particle concentration in the first and/or second samples exceeds a threshold.   
     
     
         21 . The electroplating apparatus of  claim 1 , further comprising a controller configured to:
 determine the approximate particle concentration in the first sample using the one or more liquid particle counter modules;   determine the approximate particle concentration in the second sample using the one or more liquid particle counter modules; and   send an alert to the operator of the electroplating apparatus if the magnitude of the difference between the approximate particle concentrations in the first and second samples exceeds a threshold.   
     
     
         22 . The electroplating apparatus of  claim 21 , wherein the first sampling port is located directly upstream of the electroplating cell, and the second sampling port is located directly downstream of the electroplating cell. 
     
     
         23 . The electroplating apparatus of  claim 21 , further comprising a pump, and wherein the first sampling port is located directly upstream of the pump, and the second sampling port is located directly downstream of the pump. 
     
     
         24 . A method for reducing particle concentration in an electrolyte present in an electroplating apparatus having an electroplating cell and an electrolyte circulation system for circulating electrolyte to and from the electroplating cell, the method comprising:
 directing a first sample of electrolyte from a first sampling port in the apparatus to one or more liquid particle counter modules;   determining the approximate particle concentration in the first sample using the one or more liquid particle counter modules;   directing a second sample of electrolyte from a second sampling port in the apparatus to the one or more liquid particle counter modules;   determining the approximate particle concentration in the second sample using the one or more liquid particle counter modules; and   modifying the operation of the electroplating apparatus to reduce particle concentration in the electrolyte present in the electroplating apparatus.   
     
     
         25 . The method of  claim 24 , wherein modifying the operation of the electroplating apparatus comprises:
 identifying a source of particle contamination based on the approximate particle concentration in the first sample and the approximate particle concentration in the second sample; and   replacing the source of particle contamination.   
     
     
         26 . The method of  claim 25 , wherein the source of particle contamination is a chemical or a component within the electroplating apparatus. 
     
     
         27 . The method of  claim 24 , wherein modifying the operation of the electroplating apparatus comprises:
 identifying a source of particle contamination based on the approximate particle concentration in the first sample and the approximate particle concentration in the second sample; and   diverting electrolyte away from the source of particle contamination.   
     
     
         28 . The method of  claim 27 , wherein the source of particle contamination is an electroplating cell, and wherein diverting electrolyte away from the cell comprises closing one or more valves to isolate the cell from the electrolyte circulation system.