This paper describes the deposition and properties of copper layers electroplated from a newly developed copperhexafluoro-silicate electrolytic solution. A low stress copper layer can be obtained using this electroplating technique, with a stress ratio as defined by ⌬d/d, as low as 0.0156 in the as-deposited layers. This ratio decreases to 0.0027 and a stress-free layer is formed after annealing at 300°C. This ratio, however, is held at the higher level of 0.019 in layers deposited from the conventional copper sulfate solution. Such stress reduction leads to the deposition of highly ͑111͒ oriented layers with low resistivity. For instance, the full width at half-maximum of the Cu͑111͒ X-ray diffraction spectra are 0.42 and 0.57 for this layer and for the conventional copper sulfate copper layer, respectively. The resistivity of the as-deposited layer is 1.8 ⍀ cm, and is lower than that of the copper deposited from the copper sulfate solution. Therefore, a low stress, highly ͑111͒ oriented and low resistivity copper layer can be produced by this electroplating technique.

A pH sensing channel flow double electrode was developed for pH detection of magnesium dissolution during anodic polarization. Because the hydroxide ions generated during the anodic polarization of a magnesium working electrode (Mg-WE) flow to a tungsten pH sensor (W-pH) downstream of the Mg-WE, pH changes can be detected by measuring the rest potential of the W-pH. A video recording of the Mg-WE surface was performed during the measurement, indicating that increase of pH was related to the film breakdown on Mg-WE surface. The hydrogen evolution rate of the order of 10 −8 mol cm −2 s −1 was estimated from pH values.