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Title:	MEMS three dimensional micro-transformer for low frequency applications
Authors:	Mohammad Zayed Ahmed (P42367)
Supervisor:	Burhanuddin Yeop Majlis, Prof. Dato' Dr.
Keywords:	Micro-transformer MEMS technology Low frequencies Dissertations, Academic -- Malaysia Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	1-Aug-2014
Description:	A rectangular three-dimensional shaped micro-transformer was successfully fabricated using MEMS technologies. The micro-transformer was fabricated to serve as an integretable micro-transformer for low frequencies. The main goal of this work was to realize a Malaysian authentic 3D micro-transformer using the conventional MEMS technology process to serve in transforming voltage and current in a step-up and step-down manner. Three methodologies were followed to realize the 3D MEMS micro-transformer, two of them were using alumina ceramic as the substrate while the last using the PCB. A trial to reduce the fabrication steps was investigated in addition to eliminating all of the complicated and advanced processes such as the chemical and mechanical planarization and the RIE etching process. The process was a success in fabricating the microtransformer with fewer complicated processes that are limited to the typical lithography processes, the wet chemical etching, electroplating and the planarization using the hard cured AZ-4620 photoresist. Both of the coil and magnetic core were fabricated using electroplating where both of the processes were characterized and categorized to find the optimum process that allows a descent amount of adhesion, small grain size, good material composition and electroplating rate. The coil winding was made of copper. Copper was chosen due to its good electric properties and availability; in addition to, its low cost using electrodeposition. Ni/Fe permalloy was selected as the material for the magnetic core; which was also fabricated using electro-deposition. The micro-transformer dimensions are 2560 μm X 1240 μm and the coil lengths are 1980 μm and 1160 for the primary and secondary. The magnetic coil has the dimensions of 2560 μm X 1020 μm. The width and space for both coils pads are 60 μm and 50 μm respectively, with a thickness of 15 μm. The vias have a square structure with a side length of 60 μm and the height of 25 μm. The transformer showed a high transformation efficiency of 73.75%, as a step-up transformer in the range of 10 kHz to 600 kHz, with a transformation ratio efficiency of 63.24% as a step-down transformer for the same range. The transformer inductance achieved values of 164 μH and 90 μH for the 2 coils, which consist of 18 and 10 turns at a frequency of 1 kHz with a quality factor of 16 at a frequency of 10 kHz.,Ph.D.
Pages:	200
Publisher:	UKM, Bangi
Appears in Collections:	Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

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