Title:
Active control of a diffraction grating interferometer for microscale devices

dc.contributor.advisor Kurfess, Thomas R.
dc.contributor.author Schmittdiel, Michael C. en_US
dc.contributor.committeeMember Degertekin, F. Levent
dc.contributor.committeeMember King, William P.
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2005-09-16T15:20:00Z
dc.date.available 2005-09-16T15:20:00Z
dc.date.issued 2004-07-14 en_US
dc.description.abstract This thesis describes the creation of a metrology system based upon an actively controlled diffraction grating interferometer, which measures relative linear distances. The dynamics of this sensor are estimated based on experimental testing, and a suitable controller is designed to maintain the position of the sensor in the most sensitive operating region. This controller is implemented on a field programmable gate array (FPGA) processor, which allows for flexible programming and real-time control. The sample under test is mounted atop a three axis linear stage system, which allows the diffraction grating interferometer to scan across the surface of the device, creating maps of the static and dynamic measurements. The controller is shown to maintain the sensitivity of the sensor during this operation. This insures all data are taken on the same scale, creating more accurate results. The controller increases the signal to noise ratio as compared to the system without the controller. The specifications of the entire metrology system are detailed including the sensor and controller bandwidth, the vertical and horizontal resolution, and the signal to noise ratio. A case study utilizing a capacitive micromachined ultrasonic transducer (cMUT) is presented. The sensor generates static and dynamic displacement maps of the surface of this MEMS device. The controller improves these measurements by maintaining a position of high sensitivity during operation. Finally, the preliminary results of a miniaturized version of this system are presented including the implementation of two fully independent parallel sensors. This allows for array implementation of these sensors, which is crucial for the batch fabrication photolithography techniques used to create many MEMS devices. Recommendations on the future work needed to complete the array implementation are given in conjunction with methods for increasing the resolution and robustness of the macroscale system described in this thesis. en_US
dc.description.degree M.S. en_US
dc.format.extent 8780715 bytes
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/7261
dc.language.iso en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Metrology en_US
dc.subject MEMS
dc.subject Interferometers
dc.subject Microscale
dc.subject Diffraction gratings
dc.subject Active control
dc.subject Harmonic locking
dc.subject.lcsh Metrology en_US
dc.subject.lcsh Microstructure en_US
dc.subject.lcsh Detectors en_US
dc.subject.lcsh Diffraction gratings en_US
dc.subject.lcsh Interferometers en_US
dc.title Active control of a diffraction grating interferometer for microscale devices en_US
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Kurfess, Thomas R.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 1fae7587-6ed2-4214-b785-8741ad9f465a
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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