Role of Copper Electrodeposition Additives for Via-Filling

Abstract

Role of via-filling additives for Copper electrodeposition is discussed. Addition of Cl causes macro steps. PEG forms about lOnm granular molecules and absorbs preferentially on the edge of these macro steps. This adsorption of PEG inhibits the macro step growth. About lOnm fine copper crystals form with an addition of JGB and SPS. With an addition of Cl-and PEG, the current-overpotential curves shift towards to the cathode side, which inhibits copper electrodeposition. With JGB in addition to Cl-and PEG, the curve shift towards to the cathode side with an increase in rotation speed of rotating disk electrode. This means that PEG molecules become diffusion control with JGB. We observe less adsorption of PEG molecules at via bottom if compared to that at via outside. PEG adsorption inhibits copper electrodeposition at via outside and preferentially fill the via bottom. © 2000, The Japan Institute of Electronics Packaging. All rights reserved.