Observations of inclusions of polymeric additives in copper electrodeposits by transmission electron microscopy

Abstract

The use of organic reagents as additives in metal electrodeposition processes is common practice. Typically, additives are employed in plating baths in the parts per million (ppm) concentration range and serve to enhance the quality of electrodeposited metal by deposit smoothing, deposit brightening and grain refinement. Such effects on deposit morphology are attributed in part to adsorption of reagent molecules at the electrode surface during deposition . In this paper, inclusions of PEI and PEG in polycrystalline copper electrodeposits produced in an acid sulfate electrolyte containing 10ppm of the additive have been examined by transmission electron microscopy of ultramicrotomed sections of the deposited metal. The technique of ultramicrotomy, whereby ultra thin slices of specimens, less than 10nm in thickness, are mechanically prepared by sectioning, and which in turn are suitable for examination in a transmission electron microscope has been extensively applied to studies of surface films and coatings of various kinds on a range of metals and alloys. Additionally, thin sections of bulk metal and alloy specimens containing second phase material have also been successfully prepared.