Chemical mechanical polishing is a critical enabling nanofabrication process for semiconductor devices. The current research focuses on modeling single particle and microstructural effects of CMP on copper. Currently, the student and PIs are developing skills in electropolishing, orientation imaging microscopy (OIM), nanoscratch testing, and atomic force microscopy. This project involves nanoscratch testing on different crystallographic orientations of single crystal copper and along different crystallographic directions to look at the anisotropic effects on surface deformation and lateral forces. The current goals are to understand material removal at the macroscale and at the abrasive CMP particle scale (i.e., ~300 - 500nm) with respect to microstructure.
A multi-scale, multi-physics computational model of the CMP process is also being developed in the PI’s research group. The modeling approach for this problem, known as particle augmented mixed lubrication, has been submitted for a patent. However, this model lacks a capability for introducing anisotropic effects into the CMP material removal rate predictions. Therefore, the work in the seed project is currently focused on investigating the orientation-dependence of wear by performing nanoscale scratch tests on single crystal copper along different crystallographic planes, indentified using OIM.
Grain Boundaries in Block Copolymer/Nanoparticle Composites
The initial goal is to determine the extent to which we can study polymeric microstructures using tools that we have developed for inorganic materials. During the past year we studied the effect of nanoparticle fillers on the average grain size and orientation as well as grain boundary character distribution during the film annealing process. An image analysis procedure has been developed to determine the orientation distribution function (ODF) of block copolymer microdomain structures. It has been demonstrated that the addition of particle fillers decreases both the grain coarsening kinetics during film annealing and the overall film orientation. We propose that the aggregation is driven by the associated relaxation of stretched polymer chains thus resulting in the stabilization of high energy grain boundary configurations. |
