Microfabrication Of Spiral Type Microtransformer With Magnetic Core By MEMS Technique

Portable electrical equipment is developing towards to the higher level in integration and complexity, this calls for more electrical components on smaller substrate. The largest compnents of most portable electronic devices are the magnetic elements of power supply, such as transfomers and inductors. Due to the requirement of power volume, they can not be reduced in size and weight dramatically. However, with the development of high frequency switch power supply technology, operation frequency has increased remarkable so that the size of magnetic components have also been reduced. The microminiaturization of transformers is one of most effective ways to reduce the size of power supply system and also the key to realize the electronic products with high performance, small size and light weight. Especially, micro DC-DC converters constructed by magnetic thin film microtransformer will be extensively applied in all kinds of portable electronic products. Therefore, design and fabrication of microtransformers with high performance are the important focus of scholars and researchers in power and electronics field in the world.Design and microfabrication of a spiral type microtransformer with Fe-based amorphous and nanocrystalline ribbone magnetic core by MEMS technique is studied in this thesis. MEMS techniques such as photolithography, etching, sputtering and microelectroplating technique were used to fabricate the microtransformers with different kinds of structures and magnetic core.In a word, the main work of this thesis are as follows: (1)The simulation and analysis of spiral type microtransformer with magnetic coreAccording to device analysis model, the Matlab software was used to get the performance of microtransformer as function of frequency. The calculated results are compared with the experiment data in good accordance, and can be used for the guidance of the fabrication of microtransformer in the future.(2)Properties study of magnetic core materialsComplex permeability and hysteresis loop of Fe-based amorphous and nanocrystalline ribbone are studied. Results show the material annealled at high temperature has better soft magnetic performance.(3)Microfabrication technology of spiral type microtransformer with magnetic coreMEMS were used to fabricate spiral type microtransformers with different kinds of structures and Fe-based amorphous/nanocrystalline ribbone magnetic core successfully.(4)The measurement of spiral type microtransformer with magnetic coreThe fabricated microtransformers were measured between 1~10MHz, including the parameters of ac resistance, primary inductance and quality factor of primary coil of microtransformer, the mutual inductance and couple coofficient between primary and seconday coil of microtranformer, etc. The experiment results are also compared with the calculated results.