CMP slurry measurement and control technique
AssigneeSematech, Inc.
InventorRonald A. Carpio
Life of this patent
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Abstract
Chemical mechanical polishing slurry characteristics, such as oxidant concentration and abrasive particle dispersion, are determined using electrochemical measurement techniques, such as chronoamperometry, amperometry, chronopotentiometry, ionic conductivity, or linear sweep potentiometry. Slurry characteristics may be tested and monitored independent of a CMP polishing tool. Slurry characteristics may also be automatically controlled in an on-line chemical mechanical polishing process using electrochemical measurements.
Claims22
A method of determining characteristics of a chemical mechanical polishing slurry based on a comparison of a first current value measured as a function of time with a second current value expressed as a function of time, comprising the steps of:
- providing a chemical mechanical polishing slurry having a concentration of ions;
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring the first current value of said electrical current as a function of time;
- and
- comparing said first value of current measured as a function of time with said second value of current expressed as a function of time to determine said slurry characteristics.
A method of determining slurry characteristics and controlling slurry parameters of a slurry contained in a chemical mechanical polishing system, comprising the steps of:
- providing a chemical mechanical polishing slurry having at least one slurry parameter to be controlled;
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring said electrical current;
- determining said slurry characteristics based on said measurement of said electrical current;
- and
- controlling said at least one slurry parameter based on said measurement of said electrical current.
A method of controlling slurry parameters of a slurry used in a chemical mechanical polishing process, comprising the steps of:
- providing a chemical mechanical polishing slurry having at least one slurry parameter to be controlled;
- providing a sensing apparatus, said sensing apparatus comprising a power supply, a working electrode and a counter electrode;
- said working and counter electrodes being substantially unreactive with said slurry;
- contacting said working electrode and said counter electrode with said chemical mechanical polishing slurry;
- generating an electrical current through said slurry and between said working and counter electrodes;
- measuring said electrical current;
- and
- controlling said at least one slurry parameter based on said measurement of said electrical current.
A system for controlling slurry parameters of a chemical mechanical polishing slurry having a process flow stream containing at least one slurry parameter to be controlled, comprising:
- a sensing apparatus, said sensing apparatus comprising a power supply, a working electrode and a counter electrode, said working and counter electrodes being substantially unreactive with said slurry;
- said power supply capable of generating a current through said slurry and between said working and counter electrodes when said electrodes are in contact with said slurry process flow stream;
- and said sensing apparatus capable of generating a signal representative of said at least one slurry parameter to be controlled based on said electrical current when said electrodes are in contact with said slurry process flow stream;
- a parameter control device coupled to said slurry process flow stream;
- an automatic electronic control system coupled to said sensing apparatus for receiving said slurry parameter signal, said automatic electronic control system also being coupled to said parameter control device for controlling said slurry parameter.
A method of determining dispersal of abrasive particles dispersed within a chemical mechanical polishing slurry based on a comparison of a first current value measured as a function of time with a second current value expressed as a function of time, comprising:
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring said value of said electrical current as a function of time, said value being a first value of current measured as a function of time;
- and
- comparing said first value of current measured as a function of time with said second value of current expressed as a function of time to determine said dispersal of said abrasive particles based on said step of comparing.
A method of determining and controlling characteristics of a chemical mechanical polishing slurry, comprising the steps of:
- providing a chemical mechanical polishing slurry having a concentration of oxidizing ions, said slurry contained within a chemical mechanical polishing system;
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring said electrical current;
- determining said concentration of said oxidant ions based on said measurement of said electrical current;
- and
- controlling said concentration of said oxidant ions in said slurry based on said measurement of said electrical current.
A method of determining and controlling characteristics of a chemical mechanical polishing slurry, comprising the steps of:
- providing a chemical mechanical polishing slurry having a concentration of oxidizing ions and having abrasive particles dispersed within said slurry;
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- removing either oxidant ions or abrasive particles from said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring said electrical current;
- and
- determining said slurry characteristics based on said measurement of said electrical current.
A method of determining dispersal of abrasive particles dispersed within a chemical mechanical polishing slurry, comprising:
- providing at least one working electrode comprised of an electrically conductive material that is substantially unreactive with said slurry;
- generating an electrical current between said at least one electrode and said slurry;
- measuring said electrical current;
- determining said dispersal of said abrasive particles based on said measurement of said electrical current;
- and
- controlling said dispersal of abrasive particles in said slurry based on said measurement of said electrical current;
- wherein said slurry is contained within a chemical mechanical polishing system.
Dependencies are inferred from the claim text.