Abstract-Thermal processing steps used during the production of packaged integrated circuits can lead to severe thermomechanical stresses. In addition, the process of bonding wires to contact pads can also lead to strain field generation. A feasibility study using the application of white beam synchrotron x-ray topography to packaged erasable programmable read-only memory (EPROM) Si integrated circuits (ICs) has been undertaken in order to produce maps of the strain fields induced by such processing steps. This technique provides depth-resolved mapping with spatial resolutions currently in the region of 5-10 m throughout the entire mapping volume. Furthermore, the use of different experimental geometries allows the user to nondestructively probe the strain fields present at the wafer surface right through to the back side.
Abstract:With the rising tide of antibiotic resistant bacteria, extending the longevity of the current antibiotic arsenal is becoming a necessity. Developing local, controlled release antibiotic strategies, particularly for difficult to penetrate tissues such as bone, may prove to be a better alternative. Previous efforts to develop an osteoconductive local antibiotic release device for bone were created as solid molded composites; however, intimate contact with host bone was found to be critical to support host bone regrowth; thus, an osteocondconductive antibiotic releasing bone void filling putty was developed. Furthermore, a controlled releasing polymer matrix was refined using pendant-functionalized diols to provide tailorable pharmacokinetics. In vitro pharmacokinetic and bioactivity profiles were compared for a putty formulation with an analogous composition as its molded counterpart as well as four new pendant-functionalized polymers. A best-fit analysis of polymer composition in either small cylindrical disks or larger spheres revealed that the new pendant-functionalized polymers appear to release vancomycin via both diffusion and erosion regardless of the geometry of the putty. In silico simulations, a valuable technique for diffusion mediated controlled release models, will be used to confirm and optimize this property.
Synchrotron x-ray topography was used to evaluate dislocation generation for liquid phase heteroepitaxy of strained layer In 0.97 Ga 0.03 As on n-type InAs substrates. Severe misfit dislocation generation is observed for epilayer thicknesses of 4 µm and many of these form threading dislocations which are observed at the surface. However, for thicker epilayer growth (up to 70 µm in this study), this misfit dislocation generation appears to be confined to a region close to the heterointerface, with few threading dislocations approaching the surface. These data correlates well with photoluminescence and optical microscopy measurements.
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