Thesis (Ph. D.)--Lehigh University, 2002. / Includes bibliographica references and vita.

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. Suresh K. Sitaraman; Committee Member: Dr. F. Levent Degertekin; Committee Member: Dr. Ioannis Papapolymerou; Committee Member: Dr. Madhavan Swaminathan; Committee Member: Dr. Nazanin Bassiri-Gharb. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Tummala, Rao; Committee Member: Pucha, Raghuram V.; Committee Member: Wong, C.P. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Ume, I. Charles; Committee Member: Danyluk, Steven; Committee Member: Goyal, Deepak; Committee Member: Lu, Jye-Chyi(JC); Committee Member: Michaels, Thomas; Committee Member: Sitaraman, Suresh. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Tummala, Rao; Committee Member: Iyer, Mahadevan; Committee Member: Saxena, Ashok; Committee Member: Swaminathan, Madhavan; Committee Member: Wong, Chingping.

Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Systems Science Dept., 2004 / Only abstract available. "At the request of the author, this graduate work is not available for purchase." Includes bibliographical references.

Recent advances in microelectronics and packaging industry are characterized by a progressive miniaturization in response to a general trend toward higher integration and package density. Corresponding to this are the challenges to traditional manufacturing processes. Some of these challenges can be satisfied by laser micromachining, because of its inherent advantages. In laser micromachining, there is no tool wear, the heat affected zone can be localized into a very small area, and the laser micromachining systems can be operated at a very wide range of speeds. Some applications of laser micromachining include pulsed Nd:YAG laser spot welding for the photonic devices and laser microdrilling in the computer printed circuit board market. Although laser micromachining has become widely used in microelectronics and packaging industry, it still produces results having a variability in properties and quality due to very complex phenomena involved in the process, including, but not limited to, heat transfer, fluid flow, plasma effects, and metallurgical problems. Therefore, in order to utilize the advantages of laser micromachining and to achieve anticipated results, it is necessary to develop a thorough understanding of the involved physical processes, especially those relating to microelectronics and packaging applications. The objective of this Dissertation was to study laser micromachining processes, especially laser drilling and welding of metals or their alloys, for the microscale applications. The investigations performed in this Dissertation were based on analytical, computational, and experimental solutions (ACES) methodology. More specifically, the studies were focused on development of a consistent set of equations representing interaction of the laser beam with materials of interest in this Dissertation, solution of these equations by finite difference method (FDM) and finite element method (FEM), experimental demonstration of laser micromachining, and correlation of the results. The contributions of this Dissertation include: 1)development of a finite difference method (FDM) program with color graphic interface, which has the capability of adjusting the laser power distributions, coefficient of energy absorption, and nonlinear material properties of the workpiece as functions of temperature, and can be extended to calculate the fluid dynamic phenomena and the profiles of laser micromachined workpieces, 2)detailed investigations of the effect of laser operating parameters on the results of the profiles and dimensions of the laser microdrilled or microwelded workpiece, which provide the guideline and advance currently existing laser micromachining processes, 3)use, for the first time, of a novel optoelectronic holography (OEH) system, which provides non-contact full-field deformation measurements with sub-micrometer accuracy, for quantitative characterization of thermal deformations of the laser micromachined parts, 4)experimental evaluations of strength of laser microwelds as the function of laser power levels and number of microwelds, which showed the lower values than the strength of the base material due to the increase of hardness at the heat affected zone (HAZ) of the microwelds, 5)measurements of temperature profiles during laser microwelding, which showed good correlations with computational results, 6)detailed considerations of absorption of laser beam energy, effect of thermal and aerodynamic conditions due to shielding gas, and the formation of plasma and its effect on laser micromachining processes. The investigations presented in this Dissertation show viability of the laser micromachining processes, account for the considerations required for a better understanding of laser micromachining processes, and provide guideline which can help explaining and advancing the currently existing laser micromachining processes. Results of this Dissertation will facilitate improvements and optimizations of the state-of-the-art laser micromachining techniques and enable the emerging technologies related to the multi-disciplinary field of microelectronics and packaging for the future.

No description available.

This thesis reports on a new low-cost wafer-level packaging technology for microelectromechanical systems (MEMS). The MEMS process is based on a revised version of High Aspect Ratio Polysilicon and Single Crystal Silicon (HARPSS) technology. The packaging technique is based on thermal decomposition of a sacrificial polymer through a polymer overcoat followed by metal coating to create resizable MEMS packages. The sacrificial polymer is created on top of the active component including beams, seismic mass, and electrodes by photodefining, dispensing, etching, or molding. The low loss polymer overcoat is patterned by photodefinition to provide access to the bond pads. The sacrificial polymer decomposes at temperatures around 200-280aC and the volatile products permeate through the overcoat polymer leaving an embedded air-cavity. For MEMS devices that do not need hermetic packaging, the encapsulated device can then be handled and packaged like an integrated circuit. For devices that are sensitive to humidity or need vacuum environment, hermiticity is obtained by deposition and patterning thin-film metals such as aluminum, chromium, copper, or gold. To demonstrate the potential of this technology, different types of capacitive MEMS devices have been designed, fabricated, packaged, and characterized. These includes beam resonators, RF tunable capacitors, accelerometers, and gyroscopes. The MEMS design includes mechanical, thermal, and electromagnetic analysis. The device performance, before and after packaging is compared and the correlation to the model is presented. The following is a summary of the main contributions of this work to the extensive research focused on MEMS and their packaging: 1)A new low-cost wafer-level packaging method for bulk or surface micromachined devices including resonators, RF passives and mechanical sensors is reported. This technique utilizes thermal decomposition of a sacrificial polymer through an overcoat polymer to create buried channels on top of the resonant/movable parts of the micromachined device. It provides small interconnections together with resizable package dimensions. We report MEMS package thicknesses in the range of 10 mm to 1 mm, and package size from 0.0001 mm to 1 mm. 2)A revised version of the HARPSS technology is presented to implement high aspect ratio silicon capacitors, resonators and inertial sensors in the smallest area.

No description available.