Page 6 of 797 VA Computrace by Metrohm AG

application 2 ­ cvs for the determination of organic additives in electroplating baths cyclic voltammetric stripping analysis cvs and cyclic pulse voltammetric stripping analysis cpvs are widespread methods in the electroplating industry for the determination of organic additives in electroplating baths for many technical coatings particularly in the manufacture of pcbs and semiconductor components this method forms an essential part of production control the quantitative determination of the additive is carried out indirectly via its influence on the deposition of the main components of the electroplating bath as the measurement is based on an electrode reaction that corresponds to the production process the activity of the additive and thus its effectiveness in the galvanization process can be measured directly the most important fields of application for the method are · acidic copper baths · tin-lead baths and tin baths · alkaline zinc baths quantification of the various types of additives requires special calibration techniques the socalled brighteners are determined using the linear approximation technique lat or modified linear approximation technique mlat the determination of the suppressors is carried out by dilution titration dt in these analyses a simply constructed robust and favorably-priced rotating disk electrode made of platinum is used the electrochemical conditioning of the electrode which is necessary before each measurement forms part of the determination method it is repeated automatically until the measured value remains constant with cvs or cpvs the concentration of the additive can be determined exactly the effective concentration of the particular additive in the bath sample is shown and printed out directly in ml additive per l bath liquid this means that topping up to the preset bath concentration can be carried out very accurately this guarantees continuous and interference-free operation of the unit in particular the accuracy of the analytical results has helped the method to become generally accepted in the electroplating industry other methods e.g the classical hull cell method do not allow the concentration to be determined but only provide an assessment of the quality of the deposited layer of metal 6

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