Dual Damascene Simulation for Ionized Physical Vapor Deposition Process: Investigation on Incident Energy and Via Geometry Effects

Abstract

This paper employs a dual damascene simulation to study the filling mechanisms of a dual via for the ionized physical vapor deposition (IPVD) process. The study focuses principally upon the influence of incident atom energy and via geometry upon the final dual via coverage. Additionally, the improvement in coverage which results from the use of beveled edges within the via is also considered. The molecular dynamics (MD) method is employed to simulate the filling process. The simulation is based upon three MD models, namely the dual via model, the deposition model and the potential model. Furthermore, the simulation incorporates the thermal control layer marching algorithm in order to increase the accuracy of the solution and to reduce the computational time. The results of the study show that in general, the coverage of both vias improves as the incident energy of the deposited atom increases, i.e. the filling pattern changes from anti-conformal to conformal, and then finally to super-filling as the incident energy increases. Typically, the optimum coverage of the upper via is obtained for a large via-radius ratio. However, it is found that coverage of the lower via is not only dependent upon the via-ratio, but that it is also strongly influenced by the incident energy of the deposited atoms. At lower incident energy levels, the via geometry effect governs the coverage results. However, as the incident energy increases, the incident energy effect becomes the dominant factor in determining the final coverage. It is determined that the interaction of these two effects influences the nature of the relationship between the coverage percentage and incident energy for different ranges of the via-radius ratio.