Analysis of the polishing ability of electrogenerated chemical polishing

- The polishing ability of EGCP is analyzed analytically and numerically.
- An analytic expression is given for evaluating the polishing ability of EGCP.
- Quantitative analysis of the polishing ability of EGCP is realized.

Electrogenerated chemical polishing (EGCP) had been proved effective in improving both the smoothness and the flatness of copper surface in our previous work. In this paper the polishing ability, defined as the ratio between the material removal rate at the peak and at the valley of a rough surface, is studied theoretically and experimentally. In a mathematical model, the effects of the special wavelength L, the peak-to-valley height h of the workpiece surface profile and the working distance d between working electrode and workpiece surface on the polishing ability are studied. The results show that the polishing ability decreases with increasing the working distance and finally approaches the value (d + h)/d, if L is much larger than d. However, the effect of the working distance on polishing ability is negligible, if L is close to or less than d. The polishing ability also decreases with h decreasing. Based on the above analysis, an analytical expression of the polishing ability of EGCP is given. For validating the theoretical analysis, a copper surface is polished by EGCP and the change of the surface profile is measured and analyzed using the analytical expression. The measured polishing ability agrees well with the simulation results.