Lifting Polyether Suppression during Cu Electrodeposition

Abstract

The manufacturing of semiconductor devices involves electrodeposition of copper interconnects from additive containing electrolytes. The process depends on additives that affect the local deposition rate to yield void-free superconformal or bottom–up filling of trenches and vias. Useful quantitative surfactant conservation models are available for describing the filling of high aspect ratio features ranging from nanometers (on-chip wiring) to micrometers (through-silicon-vias) to millimeters (printed circuit boards). This includes the curvature enhanced adsorbate coverage (CEAC) model as well as the additive derived S-shaped negative differential resistance (S-NDR) description of film growth and feature filling. Nonetheless, much remains to be known about the operational limits of these constructs as well as the molecular nature of the competitive, co-adsorption dynamics of the additives and their impact on metal deposition. This lecture will detail recent experiments that reveal the important role of competitive, co-adsorption of polyether, Cl-, SPS and LEV additives in controlling the hydrophilicity of the interface and thereby the rate of metal deposition and its morphological and microstructural evolution.