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Method for the Accurate Direct Measurement of Sacrificial Copper Foil Area

IP.com Disclosure Number: IPCOM000036418D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

McHatton, RC: AUTHOR

Abstract

Disclosed is a method for the direct measurement of sacrificial foil surface area for electrochemical means. This invention allows accurate measurement of absolute area in contrast to area inferred from multiple profilometer tracings.

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Method for the Accurate Direct Measurement of Sacrificial Copper Foil Area

Disclosed is a method for the direct measurement of sacrificial foil surface area for electrochemical means. This invention allows accurate measurement of absolute area in contrast to area inferred from multiple profilometer tracings.

For electrochemically reversible couples, Differential Pulse Voltammetry produces a peak-shaped waveform, the peak height of which is dependent on the absolute area of the working electrode. Thus, roughness can be measured from the ratio of the actual experimental area to the geometric area of a sample of copper foil. The figure illustrates a voltammogram obtained for ruthenium hexaammine in pH 4.50 acetic acid/sodium acetate buffer using a 6.59 square centimeter (geometric area) piece of roughened copper foil as the working electrode. In this supporting electrolyte, the copper foil being examined has a potential window from 0 to -700 mV as compared to Ag/AgC1. For ruthenium hexaammine, all parameters of the equation defining the voltammetric waveform are known in this medium. Therefore, the ratio of the actual surface area to the geometric area is obtained by dividing i(peak) by a collection of constants. For
1.00 millimolar ruthenium hexaammine and a working geometric area of 6.59 square centimeters, this collection of constants has the value 0.001. The ratio of the actual surface area to the geometric area is then obtained from R = i(peak)/C. The absolute...