| Summary: | 碩士 === 國立清華大學 === 材料科學工程學系 === 104 === Recently, the development of technology is faster and faster. People are interested in high frequency application, such as EMI shielding. By sputtering, evaporation, or spraying, conformal shielding can not only be a good shielding method, but also combine with the package directly. In this thesis, we study the shielding mechanism, finding that if the permeability of the film gets higher, the absorption loss could become larger at the same time. As a result, we would try to enhance the permeability to get higher shielding effectiveness.
At first, we established in-plane uniaxial magnetic anisotropy (IPUMA) by applying external magnetic field during sputtering. After controlling the process parameters and investigate several material systems, we found that NiFe thin film exhibits the highest permeability owing to its small anisotropy field (HK) and enough saturation magnetization (MS). Next step, we designed multilayer structure by inserting spacer layer and set crossed anisotropy to make sure permeability is high at every direction.
Finally, the shielding structure is deposited. Several problems like adhesion problem has been solved. The structure composed of soft magnetic multilayer could enhance the shielding effectiveness significantly, providing a possible solution to industry and academia for solving near field EMI problem.
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