Method of monitoring constituents in plating baths

US5320724A · kind A · utility

Assignee

• Hughes Aircraft Company · US

Inventors

• Frank A. Ludwig · Homberg (Efze), DE
• Bruce M. Eliash · Los Angeles, US
• Nguyet H. Phan · Los Angeles, US
• Vilambi NRK Reddy · Cranbury, US

Key dates

• Filing date: Nov 17, 1992
• Grant date: Jun 14, 1994
• Expiry date: Nov 17, 2012

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/49
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of monitoring a plating bath which combines ac and dc voltammetry to accurately measure major and trace constituent concentrations. The method involves applying both ac and dc voltammetric signals to a pretreated electrode in contact with the plating bath solution, measuring the ac and dc response current spectra, and comparing the resultant spectra to determine which provides maximum spectral detail for monitoring particular constituents with minimum interference from other constituents. Then, the ac and dc response current spectra are each used to monitor the particular constituents for which each provides the best accuracy. The method complements and is easily integrated with known voltammetric techniques and equipment.