X-ray characterization of Si microstructures with high spatial resolution

With the advent of the nanolithographic technologies, the demand of a local strain/stress analysis with submicrometer resolution is increasing. In particular, the aim of this work was the study of a patterned Si wafer subjected to preliminary process flow for 0.15 mum complementary metal oxide semiconductor generation. The main purpose was to follow the production of strain induced in the Si substrate during the shallow trench isolation process and subsequent formation of active stripes. The determination of structural parameters with very high spatial resolution in one dimension (300 nm) has been obtained using a scanning x-ray microscope whose main element is a waveguide for medium and high energy x-rays (8-30 keV). The experiment, which takes advantage of a nondispersive geometry, required neither a two-dimensional highly sensitive detector nor an insertion device beamline, but it has been carried out on bending magnet beamlines with relatively low flux.