Patent ID: 6592747
Filing Date: 2003-07-15
Classification: G01N

Abstract:
A method of monitoring organic addition agents comprising a suppressor component and an accelerator component in a copper plating bath which comprises cupric salt, sulfuric acid and hydrochloric acid;wherein the cupric salt concentration is at least about 0.4 molar or the sulfuric acid concentration is about 0.5 molar or less, or both; which process comprises a) obtaining a sample of said copper plating bath; b) diluting said sample with sulfuric acid and hydrochloric acid and with a cupric salt to provide a composition comprising conventional concentrations of cupric ion, sulfuric acid and hydrochloric acid, wherein said conventional concentration means about 62 g/l CuSO4.5H2O, about 160 g/l H2SO4, and about 70 mg/l HCl and adjusted concentrations of said organic addition agents wherein adjusted concentrations means of 1/X of their original values in said sample, where X is the dilution factor meaning the ratio of the volume after dilution to the volume before dilution; c) obtaining a standard solution of the suppressor component of the organic addition agents having conventional concentrations of cupric ion, sulfuric acid and hydrochloric acid and having a known concentration of the suppressor at 1/X of its target value in the plating bath; obtaining a first stock solution having the same cupric sulfate, sulfuric acid, and hydrochloric acid concentrations as the diluted sample; obtaining a second stock solution having the same cupric sulfate, sulfuric acid, and hydrochloric acid concentrations as the diluted sample and also having a known amount of an electrochemically suppressing chemical; performing a dilution titration cyclic voltammetry stripping (CVS) technique for determining the concentration of said suppressor component of the additive in the plating bath using said first stock solution and standardizing the analysis with said standard solution of the suppressor; performing a standard-addition CVS technique for determining the concentration of said accelerator component of the additive in the plating bath, using said second stock solution and standard additions of the accelerator.