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dc.contributor.advisorDavid L. Trumper.en_US
dc.contributor.authorMazzeo, Aaron D. (Aaron David), 1979-en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Mechanical Engineering.en_US
dc.date.accessioned2006-08-25T18:56:08Z
dc.date.available2006-08-25T18:56:08Z
dc.date.copyright2005en_US
dc.date.issued2005en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/33912
dc.descriptionThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.en_US
dc.descriptionIncludes bibliographical references (p. 219-224).en_US
dc.description.abstractThis thesis presents accurate capacitive sensing metrology designed for a prototype atomic force microscope (AFM) originally developed in the MIT Precision Motion Control Lab. The capacitive measurements use a set of commercial capacitance sensors intended primarily for use against a flat target. In our design, the capacitance sensors are used with a spherical target in order to be insensitive to target rotations. The moving AFM probe tip is located approximately at the center of the spherical target to make the capacitive sensing insensitive to the probe tip assembly's undesirable rotation on the order of 3 x 10⁻⁴ rad for 10 [mu]m of lateral travel [48]. To accurately measure displacement of the spherical target relative to the capacitance sensors, models for the capacitance between a sphere and a circular disc were developed with the assistance of Katherine Lilienkamp. One of the resulting non-linear models was combined with the appropriate kinematic transformations to accurately perform measurement scans on a 20 [mu]m x 20 [mu]m surface with step heights of 26.5 nm. The probe tip positions during these scans were also calculated in real- time using Lilienkamp's non-linear capacitance model with a set of transformations and 3-D interpolation techniques implemented at 10 kHz. The scans were performed both in tapping and shear detection modes.en_US
dc.description.abstract(cont.) Localized accuracy on the order of 1 nm with RMS noise of approximately 3 nm was attained in measuring the step heights. Surface tracking control and speed were also improved relative to an earlier prototype. Lateral speeds of approximately 0.8 [mu]m/s were attained in the tapping mode. In addition to improving the original prototype AFM's scan speed and ability to attain dimensional accuracy, a process for mounting an optical fiber probe tip to a quartz tuning fork was developed. This mounting process uses Post-it notes. These resulting probe-tip/tuning-fork assemblies were tested in both the tapping and shear modes. The tests in the tapping mode used the magnitude of the fork current for accurate surface tracking. The tests performed in the shear mode used the magnitude and phase of the fork current for accurate surface tracking.en_US
dc.description.statementofresponsibilityby Aaron David Mazzeo.en_US
dc.format.extent224 p.en_US
dc.format.extent11565031 bytes
dc.format.extent11574529 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectMechanical Engineering.en_US
dc.titleAccurate capacitive metrology for atomic force microscopyen_US
dc.typeThesisen_US
dc.description.degreeS.M.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Mechanical Engineering
dc.identifier.oclc66910713en_US


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