Cu via-filling is an essential technology for fabricating signal lines both on chips and on printed circuit boards and also through a silicon via in 3D wafer lever packaging for electrical devices. Generally, four additives, such as suppressors, accelerators, levelers and chloride ions, are added to a Cu electrodeposition bath in order to achieve bottom-up filling. The selection of additives and control of the additive concentrations are complex and cause increased cost and complicated quality control. In order to solve these problems, we succeeded in developing a bottom-up filling technique using only one additive, which has four types of functions. This additive is a diallylmethylamine copolymer, and contains cationic nitrogen, chloride ion and sulfur dioxide in its structure. The counter ion of the diallylmethylamine copolymer was the chloride ion or bromide ion. They were synthesized from the monomer with anions in an aqueous solution by radical polymerization. The surface morphology and cross sections of the electrodeposits were observed by scanning electron microscopy (SEM) and optical microscopy (OM). Linear sweep voltammetry (LSV) and quartz crystal microbalance (QCM) analyses were conducted. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.080204jes] All rights reserved.