Investigation of the roles of the additive components for second generation copper electroplating chemistries used for advanced interconnect metalization

This paper discusses the effects of the emerging second generation copper electrochemical deposition (ECD) bath additives on the fill mechanism for advanced interconnect trenches. The role of the accelerator (organic disulfides) and suppressor (polymers) for a two component additive package was evaluated. In addition the effects of the polymer-Cl interaction on the fill mechanism as a function of chloride ion concentration was explored. SEM cross sections of partially filled electroplated copper trenches show a two stage fill mechanism consisting of (1) conformal fill followed by (2) bottom-up fill. It was determined that the polymer-Cl complex plays a critical role during the initial stages of fill for sub one-micron trenches