System for the Simultaneous Monitoring of Constituents of an Electroplating Bath

Abstract

Methods of and apparatuses for monitoring a plating bath composition by using complex designer voltammetry. The designer waveforms are optimized in order to maximize analytical output of the solitary measurement thus drastically reducing the total time required for a full analysis of a plating bath compared to traditional analytical techniques.

We claim: 
     
         1 . A system designed to monitor concentrations of constituents of a plating bath during an electrometallization process, the system comprising:
 (a) a comprehensive electrochemical controller designed to generate one or more electrochemical waveforms;   (b) an electrochemical 3-electrode sensor having an inner compartment;   (c) a plating solution that fills the inner compartment of the sensor creating a plating bath;   (d) one or more electrochemical waveforms generated by the controller, wherein the electrochemical waveforms are applied to the sensor;   (e) an electrochemical response from the sensor, wherein said electrochemical response is subjected to a F-factor analysis that fragmentizes the electrochemical waveforms;   (f) the fragments of the electrochemical waveforms with high F-ratio, wherein the fragments of the electrochemical waveforms are used to build one or more consolidated designer waveforms; and   (g) a calibration building model created using one or more consolidated waveforms, wherein the calibration model predicts unknown concentrations of one or more constituents of a plating bath.   
     
     
         2 . The system according to  claim 1 , wherein the waveform from the electrochemical controller is applied to the electrochemical sensor. 
     
     
         3 . The system according to  claim 2 , wherein the consolidated designer waveform is a designer AC waveform comprised of segments. 
     
     
         4 . The system according to  claim 3 , wherein the designer waveform compromises a sum of multiple frequency sinewaves. 
     
     
         5 . The system according to  claim 4 , wherein the frequencies of the sinewaves are in the range of 40 Hz to 1 MHz, preferably in the range of 40 Hz to 50 kHz. 
     
     
         6 . The system according to  claim 4 , wherein the sum of the amplitude of the sinewaves is in the range of 5 mV to 1000 mV, preferably in the range of 50 mV to 500 mV. 
     
     
         7 . The system according to  claim 3 , wherein the consolidate designer AC waveform is superimposed on a DC waveform. 
     
     
         8 . The system according to  claim 7 , wherein the parameters of the DC waveform are in the range +3 V to −3 V, preferably +2 V to −2 V. 
     
     
         9 . The system according to  claim 3 , wherein the DC waveform exhibits scan rates in the range of 5 mV/s to 20 000 mV/s, preferably 10 mV/s to 5000 mV/s. 
     
     
         10 . The system according to  claim 3 , wherein the segments of the consolidated designer waveform, as the consolidated designer waveform is generated, are selected using factor analysis. 
     
     
         11 . The system according to  claim 10 , wherein selected consolidated designer waveforms have a relative F-ratio for constituent higher than 0.8, preferably higher than 0.9. 
     
     
         12 . The system according to  claim 1 , wherein the plating bath is an electroplating bath. 
     
     
         13 . The system according to  claim 13 , wherein the electroplating bath comprises one or more of the metals selected from the group consisting of Cu, Sn, Pb, Ni, Zn, Ag, Au, Cd, Co, Cr, Rh, Ru, Pd, In, Bi, and their alloys. 
     
     
         14 . The system according to  claim 1 , wherein the plating process is an electroless plating bath. 
     
     
         15 . The system according to  claim 14 , wherein the electroless plating bath is an autocatalytic bath prepared using of one or more metals selected from the group consisting of Cu, Sn, Pb, Bi, Ni, Pd, Au, Ag and their alloys. 
     
     
         16 . The system according to  claim 15 , wherein the electroless plating bath is an immersion plating bath prepared using one or more metals selected from the group consisting of Cu, Sn, Pb, Bi, Ni, Pd, Au, Ag and their alloys. 
     
     
         17 . The system according to  claim 1 , wherein the F-factor Analysis consists of an Analysis of Variance (ANOVA) having parameters together with a Squared Correlation Coefficient (R 2 ). 
     
     
         18 . The system according to  claim 17 , further comprising an analyzed multi-frequency voltammetric CDW development set data in a form of a three-way array. 
     
     
         19 . The system according to  claim 18 , wherein the parameters of the Analysis of Variance (ANOVA) for each of the constituents in the plating bath are a Standard Error (SE), a Factor Effect (FE), a Sum of Squares (SS), a Mean Square (MS), a F-ratio and a relative F-ratio. 
     
     
         20 . The system according to  claim 1 , wherein the calibration building model consists of multivariate chemometric techniques;
 wherein the calibration building model generates multivariate calibration data for one or more samples.   
     
     
         21 . The system according to  claim 20 , wherein the multivariate calibration data of a single sample is a vector. 
     
     
         22 . The system according to  claim 22 , wherein the multivariate chemometric techniques are Principal Component Regression (PCR) and Partial Least Squares (PLS). 
     
     
         23 . The system according to  claim 20 , wherein the multivariate calibration data for a single sample consists of several vectors, wherein the vectors have varying lengths. 
     
     
         24 . The system according to  claim 23 , wherein the multivariate chemometric techniques are Consensus Principal Component Regression (CPCR), Hierarchical Principal Component Regression (HPCR), Hierarchical Partial Least Squares (HPLS) and Multi-block Partial Least Squares (MBPLS). 
     
     
         25 . The system according to  claim 21 , wherein the multivariate calibration data for a single sample is a matrix. 
     
     
         26 . The system according to  claim 25 , wherein the chemometric techniques are selected from the group consisting of The Parallel Factor Analysis (PARAFAC) for multi-way array decomposition coupled with Inverse Least Squares (ILS) (PARAFAC/ILS) regression, Direct Trilinear Decomposition (DTLD) coupled with ILS (DTLD/ILS) and Multi-linear Partial Least Squares (N-PLS).