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In the search for a Pb-free compatible under-bump-metallization (UBM) barrier material, magnetron sputtering of a nonmagnetic nickel silicon alloy (NiSi) target was used to deposit a low-stress polycrystalline NiSi thin film. In the reaction with SnAg3.0Cu0.5 solder, NiSi was found to have greatly reduced reaction and intermetallics (IMC) formation rates compared with sputtered NiV. A continuous layer of IMCs in NiSi UBM-solder joint remains stable after 10 reflows and 1000 h thermal aging tests, resulting in preferred bulk solder failure mode in ball shearing/pull testing. Our results demonstrate that NiSi is a highly promising thin film barrier material suitable for Pb-free solder bumping.

The diminishing thickness of the carbon overcoat layer on a thin-film magnetic storage disk results in a greater susceptibility to corrosion and a need to move toward a fast and reliable corrosion analysis technique. A new method for quantifying corrosion levels on thin-film disks has been developed using an optical surface analyzer (OSA). High- and low-corrosion-level disks were used to develop and verify the necessary algorithms for surface analysis. The results from OSA were referenced to established methods such as scanning electron microscopy (SEM), scanning Auger microscopy (SAM), and ion chromatography (IC) wash techniques. A reliable method for identifying nickel- and cobalt-based corrosion and for separating corrosion from debris was developed. The OSA proved to be a faster and more sensitive corrosion-detection technique than SAM.

Modeling and device results demonstrate the high sensitivity of advanced transistors to small variation in junction depth. Non-destructive measurements with the Carrier Illumination/sup TM/ method correlate to NMOS drive current, RTA process variation, and small implant energy changes, demonstrating feasibility of in-line control for annealed implants.

Doping process windows are becoming very narrow as VLSI technology nodes scale to smaller and smaller dimensions. The time and cost required to develop new doping methods and the desire to re-use equipment will make it likely that current methods will be applied as long as possible. This means that existing process tools will have very tight stability and uniformity requirements, and metrology will be required to drive process control. The paper describes the state-of-the-art of both doping processes involving ion implantation and spike annealing, and new metrology based on Carrier IlluminationTM methods that will be required to implement in-line process control for these processes. CI offers depth resolution on the order of1Å, providing a level of control required to extend existing doping methods. The prospects of new methods such as Laser Thermal Annealing (LTA) are also discussed.

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

The effects of discharge conditions on the sputtering, spatial distributions and transport patterns of sputtered atoms in a demountable, radiofrequency (r.f.) glow discharge (GD) atomizer, were investigated. Results obtained for sputtering of oxygen-free hard copper indicate that the GD plume is constricted by an increase in the Ar gas pressure and disturbed by Ar gas/vacuum flow. It is shown that the glow is an inhomogeneous medium and that most of the sputtered Cu atoms are localized in the front of the sampling orifice. Independent control of flow rate and pressure of the sputtering gas (Ar) is critical in determining the spatial distribution of analyte atoms within the atomizer chamber. Both the flow rate and the pressure of the Ar gas affect the removal of ground-state atoms from the analysis volume. The plasma location at different discharge parameters was also investigated in this study. The results show that the r.f. GD source is able to sustain a stable plasma which enables the sequential atomic absorption analysis and depth profiling of samples such as metal alloys.