Chemical mechanical polishing apparatus with integrated slurry mixer-dispenser and methods for operating the same

Abstract

A chemical mechanical polishing (CMP) apparatus includes a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen, a wafer carrier configured to hold a substrate and facing the polishing pad, and an integrated slurry mixer-dispenser including at least two inlet ports configured to receive a respective slurry component, configured to generate slurry by mixing at least two slurry components provided through the at least two inlet ports, and including a dispensation port configured to dispense the slurry over the polishing pad.

What is claimed is: 
     
         1 . A chemical mechanical polishing (CMP) apparatus, comprising:
 a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen;   a wafer carrier configured to hold a substrate and facing the polishing pad; and   an integrated slurry mixer-dispenser comprising at least two inlet ports configured to receive a respective slurry component, configured to generate slurry by mixing at least two slurry components provided through the at least two inlet ports, and comprising a dispensation port configured to dispense the slurry over the polishing pad.   
     
     
         2 . The CMP apparatus of  claim 1 , wherein the integrated slurry mixer-dispenser comprises at least two in-line component-flow-control mass flow controllers that are configured to independently control a mass flow rate of a respective slurry component through a respective inlet port within the at least two inlet ports. 
     
     
         3 . The CMP apparatus of  claim 1 , wherein the integrated slurry mixer-dispenser comprises:
 a mixer-dispenser frame to which each of the at least two inlet ports and the dispensation port is attached;   at least two component feed pipes connected to a respective one of the at least two inlet ports;   a mixing chamber connected to each of the at least two component feed pipes; and   a dispensation pipe connecting the mixing chamber and the dispensation port.   
     
     
         4 . The CMP apparatus of  claim 3 , further comprising at least two in-line component-flow-control mass flow controllers that are connected to the at least two component feed pipes and configured to independently control a mass flow rate of a respective slurry component therethrough. 
     
     
         5 . The CMP apparatus of  claim 1 , further comprising:
 an endpoint detection system configured to detect a change in a removal rate of materials from the substrate and to generate an endpoint detection signal; and   a process controller configured to receive the endpoint detection signal and to change at least one mass flow rate among mass flow rates of the at least two slurry components.   
     
     
         6 . The CMP apparatus of  claim 5 , wherein:
 the at least two slurry components comprise a first slurry component and a second slurry component; and   the process controller is configurated to change a ratio of a mass flow rate of the first slurry component to a mass flow rate of the second slurry component after receipt of the endpoint detection signal.   
     
     
         7 . The CMP apparatus of  claim 5 , wherein the endpoint detection system is configured to measure an increase in torque on a drive motor of the platen above a threshold value, and to generate the endpoint detection signal upon measurement of the torque above the threshold value. 
     
     
         8 . The CMP apparatus of  claim 7 , wherein the process controller comprises a processor that is configured with processor executable instructions to:
 monitor the torque on the drive motor of the platen after the endpoint detection signal is generated; and   maintain the torque on the drive motor within a target torque range by continually adjusting the at least one mass flow rate among the mass flow rates of the at least two slurry components.   
     
     
         9 . The CMP apparatus of  claim 5 , further comprising:
 an additional polishing pad located on a top surface of an additional platen configured to rotate around an additional vertical axis passing through the additional platen; and   an additional wafer carrier configured to hold an additional substrate and facing the additional polishing pad,   wherein the integrated slurry mixer-dispenser comprises an additional dispensation port configured to dispense the slurry over the additional polishing pad.   
     
     
         10 . The CMP apparatus of  claim 9 , further comprising an additional endpoint detection system configured to detect a change in a removal rate of materials from the additional substrate and to generate an additional endpoint detection signal, wherein the process controller is configured to change the at least one mass flow rate among the mass flow rates of the at least two slurry components after receiving the endpoint detection signal and the additional endpoint detection signal, and to reduce a downforce on the substrate until the additional endpoint detection signal is generated or to reduce a downforce on the additional substrate until the endpoint detection signal is generated. 
     
     
         11 . A chemical mechanical polishing (CMP) apparatus, comprising:
 a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen;   a wafer carrier configured to hold a substrate and facing the polishing pad;   an endpoint detection system configured to detect a change in a removal rate of materials from the substrate and to generate an endpoint detection signal; and   a process controller configured to receive the endpoint detection signal and to change a mixture rate for slurry comprising at least two slurry components and applied to the polishing pad.   
     
     
         12 . The CMP apparatus of  claim 11 , further comprising an integrated slurry mixer-dispenser comprising at least two inlet ports configured to receive a respective slurry component among the at least two slurry components, configured to generate the slurry by mixing the at least two slurry components, and comprising a dispensation port configured to dispense the slurry over the polishing pad. 
     
     
         13 . The CMP apparatus of  claim 12 , wherein the integrated slurry mixer-dispenser comprises:
 a mixer-dispenser frame to which each of the at least two inlet ports and the dispensation port is attached;   at least two component feed pipes connected to a respective one of the at least two inlet ports;   a mixing chamber connected to each of the at least two component feed pipes; and   a dispensation pipe connecting the mixing chamber and the dispensation port.   
     
     
         14 . The CMP apparatus of  claim 11 , wherein:
 the at least two slurry components comprise a first slurry component and a second slurry component; and   the process controller is configurated to change a ratio of a mass flow rate of the first slurry component to a mass flow rate of the second slurry component after receipt of the endpoint detection signal.   
     
     
         15 . The CMP apparatus of  claim 14 , wherein the process controller comprises a processor that is configured with processor executable instructions to:
 monitor torque on a drive motor of the platen after the endpoint detection signal is generated; and   maintain the torque on the drive motor within a target torque range by continually adjusting the ratio of the mass flow rate of the first slurry component to the mass flow rate of the second slurry component.   
     
     
         16 . A method of operating a chemical mechanical polishing (CMP) system, comprising
 providing a CMP apparatus comprising a polishing pad located on a top surface of a platen configured to rotate around a vertical axis passing through the platen, a wafer carrier facing the polishing pad, and an endpoint detection system configured to detect a change in a removal rate of materials during a polishing process;   loading a substrate on the wafer carrier;   performing a main polishing step that polishes a portion of the substrate by applying a downforce to the substrate through the wafer carrier while applying slurry comprising at least two slurry components; and   performing a terminal polishing step after changing a mixture rate for the slurry.   
     
     
         17 . The method of  claim 16 , wherein the slurry is dispensed using an integrated slurry mixer-dispenser that comprises at least two inlet ports configured to receive a respective slurry component among the at least two slurry components, is configured to generate the slurry by mixing the at least two slurry components, and comprises a dispensation port that dispenses the slurry over the polishing pad. 
     
     
         18 . The method of  claim 17 , wherein the integrated slurry mixer-dispenser comprises:
 a mixer-dispenser frame to which each of the at least two inlet ports and the dispensation port is attached;   at least two component feed pipes connected to a respective one of the at least two inlet ports;   a mixing chamber connected to each of the at least two component feed pipes; and   a dispensation pipe connecting the mixing chamber and the dispensation port.   
     
     
         19 . The method of  claim 16 , wherein:
 the at least two slurry components comprise a first slurry component and a second slurry component; and   the method comprises changing a ratio of a mass flow rate of the first slurry component to a mass flow rate of the second slurry component prior to performing the terminal polishing step.   
     
     
         20 . The method of  claim 19 , further comprising:
 monitoring torque on a drive motor of the platen during the terminal polishing step; and   maintaining the torque on the drive motor within a target torque range by continually adjusting the ratio of the mass flow rate of the first slurry component to the mass flow rate of the second slurry component during the terminal polishing step.