| In this dissertation four areas of investigation are discussed. First is research on the use of a tuning fork based probe as a new generation micromanipulation tool with force sensing capabilities. The resultant system may be considered a merging of micrometer diameter, oscillating, fiber-based tweezers with micro/nano CMM capabilities. If one or more probes are used as a tweezers it was shown that it is possible to lift objects from around 10 mum up to 300 mum in size from the specimen tray relying only on adhesion force between probe and specimen. Driving the probe near to its resonance it was shown that it is possible to break adhesion bonds between gripped object and fiber so that it could be released. Monitoring feedback from amplitude and phase change of the oscillator drive signal could be used to detect contact with an object and as a confirmation signal that an object was released. Being able to detect contact, the micro tweezers system based on tuning fork probes can also be used as a micro/nano CMM machine to measure dimensions of objects, verify if assembled objects are positioned properly or to measure geometric properties of micro features previously assembled taking advantage of this fiber as a high aspect ratio probe.;Second part of this thesis research focused on a novel method for surface modification of a substrate material based on the generation of localized vortices of abrasive slurry using slender oscillating fibers. Using such a technique, it has been possible, over machining times of 6--24 hours, to produced localized depressions in the surface of a silicon substrate with typical depths of around 60--700 nm and widths of around 10--300 mum with the surface deviations (roughness) in the region 1--2 nm.;Third research investigated electrochemical etching of tungsten in KOH as a method for precise volume and mass removal. During this process, an electric current was carefully measured and a charge passing through tungsten and through the KOH electrolyte was measured. Based on chemical reactions, it is theoretically possible using parameters traceable to fundamental constants correlate measured charge with mass removed. This approach was verified with NIST by a double blind test method in experiments for which the largest deviation between NIST and electrolytically measured mass removal was 0.5 mug in experiments where more than 300 mug were removed. Ongoing research aims to quantify this method as a cost effective and traceable calibration tool or differential mass standard in situations where dead weights or other methods cannot be applied or at small values (less than 0 1 mg) for which mass standards do not currently exist.;Fourth research in the collaboration between UNCC and NIST is to design, build and calibrate first, vacuum compatible nanoindentation machine which is directly traceable to NIST standards ultimately to be used to prepare reference materials to calibrate other nanoindenters. Some of the features of the design are: a) optimal separation of metrology loop from force loop, b) elimination of the influence of the machine's stiffness on the measurement by accommodating unique, symmetric nulling mechanism that will track specimen in close proximity to indentation region and be a reference for indentation depth measurement, c) directly traceable self-calibration of force gauge by use of electrostatic force balance technique built into specially designed, diamond turned capacitance gauges, d) accommodation for a fiber optics based, Fabry-Perot laser interferometer used as a displacement sensor characterized by noise limited resolution of 2 pm. The entire system will be enclosed in the vacuum chamber, which also acts as a Faraday cage to minimize an electric noise, on double vibration isolation platforms in temperature controlled environment. |
