Optimization of trench filling during copper electrodeposition by additives and pulse plating

摘要

Optimization of copper electrodeposition for microtrench filling was studied numerically by a method which includes adaptive meshing capabilities for modelling the shape evolution. The cases of electrodeposition by additives in the electrolytic solution and by pulse plating were investigated. The mathematical model includes fluid flow, transport by diffusion, migration and convection, multiple species, reactions, moving boundaries and three-dimensional capabilities. For electrodeposition by additives the chemistry mechanism was based on additive competition for free sites on the active surface, thus suppressing copper kinetics. In pulse plating, transient behaviour was simulated with time. Two numerical codes, ERMES and FIDIPIDDIS, based on finite difference for general curvilinear coordinates, were developed. The process parameters, such as additive compositions and pulse plating parameters, were optimally adjusted to minimize the void.