| AVS 65th International Symposium & Exhibition | |
| Applied Surface Science Division | Thursday Sessions |
| Session AS-ThP |
| Session: | Applied Surface Science Division Poster Session |
| Presenter: | Kathryn Lloyd, DuPont Corporate Center for Analytical Sciences |
| Authors: | K.G. Lloyd, DuPont Corporate Center for Analytical Sciences J.R. Marsh, DuPont Corporate Center for Analytical Sciences |
| Correspondent: | Click to Email |
Differences in chemistry across monolithic or multi-layered films are often critical to product performance. Each component in a formulation serves a purpose. It is important to be able to monitor the integrity of multi-layered structures, the striation or migration of components, the enrichment of components at interfaces, and the formation of buried defects.
Approaches used to obtain this information can be broadly separated into cross-sectioning (combined with chemical mapping) and depth profiling (with or without chemical mapping). Cross-sectioning calls for more labor up front to prepare the samples – potting in epoxy; microtoming -- but the resulting cross-sectional surfaces are amenable to multiple chemical mapping techniques, such as Raman microprobe, secondary ion mapping, and Energy Dispersive Spectroscopy (SEM/EDS), all of which exhibit comparable lateral resolution (around 1 micron). Depth profiling requires little to no sample preparation and offers higher depth resolution (10s of nanometers).
To a large degree, film and/or layer thickness determine the approach pursued. Practical depth profiling historically has not extended much more than 10 microns into a surface. Thus, for multilayer films with thicknesses on the order of 25 microns or more, cross-sectioning has been preferred. This can present problems for surface chemical mapping techniques such as ToF-SIMS, when even cryo-microtoming can result in a thin overlayer of smeared epoxy components covering the surface.
The advent of new gas cluster ion beam (GCIB) sputter sources has not only enabled cross-sectional ToF-SIMS mapping analysis for layered and heterogeneous organic systems, but has also made the choice between cross-sectioning and depth profiling not as clear. GCIB depth profiling through organic or polymeric material can be very efficient, making the idea of profiling through 25 microns or more not as impractical as it once was.
This presentation will show examples of cross-sectional mapping analysis and sputter depth profiling, exploring which factors can influence the choice of approach and illustrating some of the trade-offs involved.