Material Characterization and the Formation of Nanoporous PMSSQ Low-K Dielectrics

A novel metrology strategy has been developed and applied to characterize the complex chemical transformations which are required to form spin-cast nanoporous low-K materials. Surface analysis based on Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) has been applied in static and dynamic modes, and coupled with X-ray Photoemission Spectroscopy (XPS), to observe the compositional and chemical bonding changes of the surface and the underlying thin film. Results show the cross-linking of the low-K matrix as a function of thermal processing, along with details of the evolution of porogen species that provide the template for forming nanovoids in the fully-processed material. This approach is promising more generally for characterizing materials transformations, particularly those involving polymeric systems where ToF-SIMS analysis of large molecular fragments represents a highly specific analytical tool