Three-Dimensional Feature-Scale Modeling of CMP

Abstract

In Chapter 6, a one and semi-two dimensional model based on linear elasticity and viscoelasticity is developed to investigate feature- and die-scale topography evolution. The influences of lateral directional parameters such as line width on the topography evolution in the vertical direction can be evaluated using the look-up table based semi-two dimensional model. The advantage of the model is that the computation time is minimal. It can be integrated into a design for manufacturing software to investigate the effects of process parameters on circuit performance. However, it is not able to predict exactly the two and three dimensional shape evolution of the features during the CMP process, which may be a concern in some applications. For instance, an exact three-dimensional shape of the copper dishing may help to extract the accurate resistor of a copper line under a certain process; the edge rounding of the alignment mark generated by CMP may create problems for the lithography process following CMP. A three-dimensional model with capability in topography evolution will help obtain the optimal design of alignment marks.