Three-Dimensional Simulation of the Conformality of Copper Layers Deposited by Low-Pressure Chemical Vapor Deposition from CuI(tmvs)(hfac)

In this paper, an approach is presented which is suitable for predicting the shape of copper layers deposited by low-pressure chemical vapor deposition (LPCVD) on three-dimensional (3D) features as used in semiconductor technology. The 3D simulations are based on a physical model assuming reactive molecules arriving at the substrate. These molecules react with a certain probability, the so-called sticking coefficient. In order to be able to predict the topography of the deposited layers, the sticking coefficient has to be determined for the set of process conditions under investigation. In this work, values for copper LPCVD from literature were used which have been obtained by comparing 2D simulations to 2D measurements. As result of the 3D simulations, the step coverage for contact holes of different aspect ratios is predicted. The simulator used does not make any restriction concerning the shape of the feature to be simulated. As an example, copper deposition into a dual-damascene structure is investigated by means of 3D simulation.