Method for determination of concentration of organic additive in plating bath
AssigneeInternational Business Machines Corporation
InventorsPerminder S. Bindra, Allan P. David, Raymond T. Galasco, David N. Light
Life of this patent
Estimating the term…
Abstract
The concentration of an organic additive in a plating bath is determined by providing a polished and constant current density preplated rotating disc cathode, a reference electrode and anode in an electrolytic copper plating bath, passing an electric current from the anode to the cathode and reference electrode; measuring the voltage difference between the cathode and reference electrode; and comparing the difference to values for known concentrations of the organic additive.
Claims22
A method of determining the concentration of at least one organic additive in an acidic electrolytic copper plating bath comprising the steps of:
- (a) preparing a cathode by electroplating a copper film onto a substrate by immersing the substrate in a copper plating bath and preplating copper thereon at a constant current density and constant voltage;
- said cathode being a rotating disk electrode;
- (b) providing in an acidic electrolytic copper plating bath, said cathode from step (a), a reference electrode, and an anode;
- (c) passing an electric current at a constant current density from said anode to said cathode;
- (d) measuring the voltage difference between said cathode and said reference electrode;
- and
- (e) comparing the measured voltage difference from step (d) with previous measured values for known concentrations of said organic additive.
The method of claim wherein said value is about 1% by volume.
Dependencies are inferred from the claim text.