Measurement of stress evolution in pulse-reverse electrochemical deposition using Micro-Raman Spectroscopy

Abstract

Nowadays, copper deposit is extensively used in microelectronic applications, because the electroplated copper exhibits excellent electrical conductivity along with high hardness. in the resent literature, it is known that copper electroplated with pulse reverse current produces larger hardness than that by DC (direct current) plating or PC (pulse current)plating.

The residual stress is introduced from the copper electroplating process. It shows an increasing tension stress profile. And the stress in the copper layer is higher than that in the silicon layer. With an additive free electrolyte, the stress increased to around 40 Mpa, while it was about 200 Mpa in copper deposit. Compare with it, the stress became lower if the organic additive for brightening added into the electrolyte.