Abstract
We used a 10 MHz quartz crystal microbalance (QCM) to detect small mass changes during the copper corrosion phenomena. Copper corrosion in de-ionized water (DIW) was evaluated in terms of dissolved oxygen (DO) and conductivity (S) of DIW. It was not sufficient to suppress the DO concentration in DIW alone to decrease the copper corrosion rate. Suppression of DIW conductivity also becomes necessary when a potential difference exists on Cu films locally. The time constant for the diffusion of oxygen into a DIW layer was 0.6 sec in a 10 um layer and 0.06 sec in a 1 um layer. This shows that the oxygen diffusion into DIW is significantly fast. We were able to estimate that in an actual spin-rinse-dry (SRD) process, the DIW layer was immediately saturated in oxygen in atmospheric conditions.
