Simulation of shape evolution during electrodeposition of copper in the presence of additives

Shape evolution during electrodeposition of copper in microtrenches was studied numerically by a model which incorporates adaptive meshing capabilities. Filling of trenches with copper without creating a void or a seam was related to plating additives in solution. The shape-change behavior of this system resulting from variation of the feature's aspect ratio, bulk composition and level of additive components was investigated. It was illustrated that the attribute of superconformal deposition, herein called superfilling, is facilitated at shallower features for the conditions studied in the present work. The operating window of bath conditions for engineering electrodeposition to produce superfilling performance was studied in the range of 10(-4) to 10(-1) M bulk concentration of additive in a 1.5 M CuSO4 + 0.05 M H2SO4 plating solution and for aspect ratios (depth:width) from 0.5 to 4. The mathematical model includes fluid flow, transport by diffusion, migration and convection, multiple species and reactions in complex geometries. It is incorporated in a collaborative Web-based modeling environment providing a friendly interface for linking models at a variety of scales.