The Mechanics of CMP and Post-CMP Cleaning

Goals and Objectives The goal of our activities is to conduct a detailed analysis of the mechanics of particle, wafer and pad (or brush) interaction in CMP and post-CMP cleaning processes. We propose to study the real contact pressure at the interface between the pad and wafer, pad and particle or particle and wafer as a function of pad or wafer asperity distribution, deformation and height. The contact pressure variation can also be measured experimentally as a function of engagement height. Consequently, the relation between the real contact pressure and the apparent contact pressure, i.e., pr = g(pa), can be established. The apparent contact pressure over the contact area results from the macro scale force equilibrium of the two contacting bodies. This analysis and model will have the capability to bridge the fluid and solid mechanics at the macro level with the forces required for the interaction of particles with the wafer and pad at the micro level.