9358380 West This is a critical evaluation of electrodrodynamic (EHD) impedance spectroscopy as a means of investigating anodically formed films. A second objective is to establish the mechanisms of electropolishing. Alternating - current (AC) and EHD impedance spectroscopy methods are used to study the electropolishing of copper in concentrated phosphoric acid and in a neutral-salt electrolyte. It has been shown previously that a salt film forms on the electrode surface during electropolishing in neutral-salt electrolyte. The electrical properties of these films are determined with AC impedance, and transient changes in electrical properties with film growth are monitored by EHD impedance; this leads to inferences about structural properties and mechanisms of conduction in the films. In contrast, it has been established whether a solid film is formed when metals are electropolished in concentrate acids. This is examined with EHD impedance, which can also test alternatives mechanisms for electropolishing. The result of this research are directly applicable to monitoring and control of production processes used in the electronics and semiconductor industries.
