Role of Cuprous Ion in Copper Electrodeposition Acceleration - a Rotating Ring Disk Study

Abstract

We have already reported the cuprous ion concentration inside the via is closely related to void decreases and bottom-up via filling during copper electrodeposition. And further, observed the deposition current acceleration at through mask trench electrode when the substrate is pre-dissolved under nitrogen gas atmosphere with SPS and chloride added bath. In this paper we measured the changes in reaction intermediates concentration with the additives of SPS and chloride ion by using rotating ring disk electrode, and found as follows. In copper deposition at the disk electrode with adding Chloride and SPS or MPS, a marked increase in ring currents, which are the amounts of cuprous intermediates, were observed, and the largest current with 6ppm of MPS and 50ppm of Chloride. While, the ring deposition current markedly increased if the cuprous was supplied with additives of SPS and Chloride. MPS accelerate current more than SPS with cuprous supply.

Effect of Halides on MPS Orientation and Cu Deposition Rates at Cu Surfaces

“…This peak, consistent with prior reports, is due to an increase in Cu(I) concentration at the surface. 11,12,37,38 I − plateaus multiple times throughout the cathodic sweep. Stable CuI complexes can form under electrodeposition conditions which can passivate the Cu surfaces.…”