Focused Ion Beam Lift Out Cross Sectional Transmission Electron Microscopy of Polymer Nanostructured Films Ordered on Attractive Surfaces

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

A two component polymer system, such as a homopolymer blend or a block copolymer melt, in the vicinity of an interactive surface is an inherently inhomogeneous system. The difference in chemical affinity between the components and the substrate induces a preferred orientation in the system. In most studies of this nature, silicon has been the substrate of choice since it can be obtained in single crystal form with an atomically smooth surface. Furthermore, it is used extensively in the semiconductor industry where numerous procedures have been developed to modify the surface energy and apply both chemical and topographical patterns. Most of what is known today on the orientation of polymers at surfaces has been obtained by neutron and x-ray reflectivity methods or dynamic secondary ion mass spectrometry. These methods work best when the orientation occurs normal to the surface and is symmetric in the plane parallel to the surface. Transmission electron microscopy studies of thin polymer films ordered on atomically smooth silicon have been very difficult for cross-sectional specimens. It was not possible to directly section heard silicon crystals by ultramicrotomy and ion milling is a long and tedious process with uncertain results. %%% This award under NSF 94-147 "Minority Research Planning Grant" provides initial funding to establish a polymer nanostructured electron-microscopy program at SUNY Stony Brook and to investigate compatibilization of homopolymer blends ordered on attractive surfaces. The following issues will be addressed in this initial study: (a) Can the focused ion-beam lift-out procedure be used to produce cross sections of novel thin films ordered on silicon? (b) Can uniquely tailored polymer nanostructures induce miscibility in hompolymer blends?