Investigation of organic additives to regulate growth and signal transmission loss of copper interconnection structure

Abstract

<p indent=0mm>Signal integrity is severely limited by the copper roughness. Plating solution containing different organic additives could influence the roughness of electroplating copper growth. Molecular simulation and electrochemical tests were used to regulate the competitive adsorption behavior of organic additives on the copper surface and understand the possible mechanism on the difference of copper growth. The results show that the plating solution system containing bis-(sodium sulfopropyl)-disulfide (SPS), ethylene oxide-propylene oxide copolymer (EO/PO) and Janus Green B (JGB) can contribute to the copper growth with smooth surface, leading to insertion loss of <sc>−8.9 dB@20 GHz.</sc> Therefore, organic additives could be used to regulate the low-profile growth of copper interconnection structure and reduce transmission loss to effectively ensure the integrity of high-frequency signal transmission.