Electrochemical sensing and data analysis system, apparatus and method for metal plating

Abstract

An electrochemical sensing and data analysis system (and apparatus and methods) adapted for control of electroplating of various metal(s) on a wafer or other suitable substrate. Components of the system utilize multi-variate analysis (MVA) and galvanostatic, potentiodynamic or other electrical measurements (or combinations thereof) to predict, adjust or control plating parameters, e.g., to achieve improved yield of plated substrates with acceptable levels of defects (or lack thereof).

1 . A system adapted to analysis of an electroplated substrate or adapted to analysis for electroplating a substrate, said system comprising:
 (a) a galvanostatic measurement component, a potentiodynamic measurement component or a combination thereof adapted to measuring galvanostatic data, potentiodynamic data or a combination thereof from a plating bath;   (b) a storage component adapted to storing said galvanostatic data, said potentiodynamic data or a combination thereof;   (c) a first multi-variate analysis component adapted to correlating said galvanostatic data, said potentiodynamic data or said combination thereof with a defect profile of said electroplated substrate, a chemical profile of said plating bath, an electrical performance profile of said electroplated substrate or a combination thereof;   (d) an optional second multi-variate analysis component adapted to correlating said defect profile with said chemical profile of said plating bath;   (e) an optional third multi-variate analysis component adapted to correlating said galvanostatic data, said potentiodynamic data or said combination thereof with said chemical profile of said plating bath; and   (f) an optional fourth multi-variate analysis component adapted to correlating said electrical profile of said electroplated substrate with said defect profile, said chemical profile or a combination thereof.   
   
   
       2 . The system of  claim 1 , further comprising:
 (g) a comparator component adapted to determining if said defect profile, said chemical profile, or said electrical profile is outside a defect threshold range, a chemical threshold range, or an electrical threshold range, respectively.   
   
   
       3 . The system of  claim 2 , further comprising:
 (h) a chemical profile manager adapted to adjusting said chemical profile if said defect profile is outside said defect threshold range, if said chemical profile is outside said chemical threshold range, or if said electrical profile is outside said electrical threshold range—then—to return said defect profile to fall within said defect threshold range, to return said chemical profile to fall within said chemical threshold range, or to return said electrical profile to fall within said electrical threshold range.   
   
   
       4 . The system of  claim 1 , further comprising:
 (i) an output of said first, second, third, or fourth multi-variate correlation or a combination thereof.   
   
   
       5 . The system of  claim 2 , further comprising:
 an output of said first, second, third, or fourth multi-variate correlation or a combination thereof.   
   
   
       6 . The system of  claim 1 , wherein said galvanostatic data comprises voltage versus time data of said electroplated substrate. 
   
   
       7 . The system of  claim 1 , wherein said galvanostatic measurement, said potentiodynamic measurement or said combination thereof is measured in a testing cell during electroplating or stripping a metal from a working electrode, said testing cell comprising (aa) a reference electrode (RE), (bb) a working electrode (WE), (cc) a counter electrode (CE), (dd) electroplating driving electronics electrically and operatively coupled between the reference electrode (RE), the counter electrode (CE), and the working electrode (WE) to electroplate metal on said working electrode in a metal electroplating bath, and (ee) electrical potential measuring circuitry electrically and operatively coupled between the reference electrode (RE), the counter electrode (CE) and the working electrode (WE), wherein the electroplating driving electronics may further comprise stripping driving electronics to remove plated metal from the working electrode (WE). 
   
   
       8 . The system of  claim 7 , wherein said reference electrode is an Ag/AgCl reference electrode (RE) optionally fitted with an asbestos junction. 
   
   
       9 . The system of  claim 8 , wherein said working electrode is a Pt electrode optionally encased in lead glass and operated at a voltage range selected from the group consisting of ≧0.1V, ≧0.2V, ≧0.3V, ≧0.4V, ≧0.5V, ≧0.6V, ≧0.7V, ≧0.8V, ≧0.9V, ≧1.0V, ≧1.1V, ≧1.2V, ≧1.3V, ≧1.4V, ≧1.5V, ≧1.6V, ≧1.7V, ≧1.8V, ≧1.9V, and ≧2.0V relative to a standard hydrogen electrode (SHE). 
   
   
       10 . The system of  claim 7 , wherein said metal plating bath comprises a copper salt, a halide, and an acid and optionally a suppressor, an accelerator, a leveler or a combination thereof. 
   
   
       11 . The system of  claim 10 , wherein said copper salt is copper sulfate, said halide is chloride, and said acid is sulfuric acid or hydrochloric acid. 
   
   
       12 . A system adapted to defect analysis on an electroplated substrate or adapted to defect analysis for electroplating a substrate, said system comprising:
 (a) a galvanostatic measurement component, a potentiodynamic measurement component or a combination thereof for measuring galvanostatic data, potentiodynamic data or a combination thereof from a plating bath;   (b) a storage component for storing said galvanostatic data, said potentiodynamic data or a combination thereof;   (c) a component for comparing said data with a rule set for determining adjustment(s) to said plating bath wherein said rule set comprises a defect profile including a defect threshold range for at least one of surface roughness, voids, hardness, surface contamination, crystallographic orientation, grain size, bulk contamination and structural integrity, and wherein said adjustment(s) to said plating bath are determined without measurement of concentration of chemical components in said plating bath.   
   
   
       13 . A method adapted to forming an electroplated substrate, said method comprising the steps of:
 (a) performing or obtaining a galvanostatic measurement, a potentiodynamic measurement or a combination thereof relating to said electroplated substrate with a testing cell containing (aa) a reference electrode (RE), (bb) a working electrode (WE), (cc) a counter electrode (CE), (dd) electroplating driving electronics electrically and operatively coupled between the reference electrode (RE), the counter electrode (CE), and the working electrode (WE) to electroplate metal on said working electrode in a metal electroplating bath, and (ee) electrical potential measuring circuitry electrically and operatively coupled between the reference electrode (RE), the counter electrode (CE) and the working electrode (WE), wherein the electroplating driving electronics may further comprise stripping driving electronics to remove plated metal from the working electrode (WE);   (b) storing said galvanostatic measurement, said potentiodynamic measurement or said combination thereof;   (c) correlating said galvanostatic measurement, said potentiodynamic measurement or said combination thereof with a defect profile of said substrate, with a chemical profile of an electroplating bath in which said substrate is/was electroplated, or a combination thereof utilizing multi-variate analysis; and   (d) replacing said electroplating bath or adjusting one or more chemicals in said electroplating bath if a defect profile of said electroplated substrate is outside a defect threshold range, if a chemical profile of said electroplating bath is outside a chemical threshold range or a combination thereof.   
   
   
       14 . The method of  claim 13 , wherein said electroplating bath comprises a copper salt, a halide, and an acid and optionally a suppressor, an accelerator, a leveler or a combination thereof. 
   
   
       15 . The method of  claim 14 , wherein said copper salt is copper sulfate, said halide is chloride, and said acid is sulfuric acid or hydrochloric acid. 
   
   
       16 . The method of  claim 13 , wherein said reference electrode is an Ag/AgCl reference electrode optionally fitted with an asbestos junction. 
   
   
       17 . The method of  claim 13 , wherein said working electrode is a Pt electrode optionally encased in lead glass and operated at a voltage range selected from the group consisting of ≧0.1V, ≧0.2V, ≧0.3V, ≧0.4V, ≧0.5V, ≧0.6V, ≧0.7V, ≧0.8V, ≧0.9V, ≧1.0V, ≧1.1V, ≧1.2V, ≧1.3V, ≧1.4V, ≧1.5V, ≧1.6V, ≧1.7V, ≧1.8V, ≧1.9V, and ≧2.0V relative to a standard hydrogen electrode (SHE). 
   
   
       18 . The method of  claim 13 , wherein between said steps (a) and (b) is interposed a step of (a′) cleaning said testing cell with a cleaning solution. 
   
   
       19 . The method of  claim 13 , wherein said step (a) is conducted a plurality of times to generate galvanostatic measurement data, potentiodynamic measurement data or a combination thereof and said data is stored during said step (b). 
   
   
       20 . The method of  claim 18 , wherein said cleaning solution comprises sulfuric acid and water and optionally one or more additives selected from the group consisting of a suppressor, an accelerator, a leveler or a combination thereof. 
   
   
       21 . The method of  claim 20 , wherein said cleaning solution contains a leveler. 
   
   
       22 . The method of  claim 21 , wherein said leveler in said cleaning solutions is provided in a concentration of about 1.5 ml per liter of cleaning solution. 
   
   
       23 . The method of  claim 20 , wherein said step (a) is conducted during a plating potential cycle or during a stripping potential cycle. 
   
   
       24 . An apparatus comprising the system of  claim 1 . 
   
   
       25 . The system of  claim 1  comprising said second multi-variate component, said third multi-variate component, said fourth multi-variate component or a combination thereof. 
   
   
       26 . The system of  claim 1 , wherein said first multi-variate analysis component is adapted to correlate at least of one said defect profile, chemical profile, and electrical performance profile by transformation of said galvanostatic data, said potentiodynamic data or said combination thereof to an averaged data set thereof including a linearized transformation thereof versus time against the defect profile corresponding to said galvanostatic data, potentiodynamic data or combination thereof. 
   
   
       27 . The system of  claim 1 , wherein said first multi-variate analysis component is adapted to correlate at least of one said defect profile, chemical profile, and electrical performance profile by transformation of said galvanostatic data, said potentiodynamic data or said combination thereof to an averaged data set thereof including a linearized transformation thereof versus time against the chemical profile corresponding to said galvanostatic data, potentiodynamic data or combination thereof. 
   
   
       28 . The system of  claim 1 , wherein said first multi-variate analysis component is adapted to correlate at least of one said defect profile, chemical profile, and electrical performance profile by transformation of said galvanostatic data, said potentiodynamic data or said combination thereof to an averaged data set thereof including a linearized transformation thereof versus time against the electrical profile corresponding to said galvanostatic data, potentiodynamic data or combination thereof.