Synthesis of near future electromagnetic noise suppressor with nano-granular structure and their application to electric devices.

1. GHz频段电磁噪声抑制研究：研究了不同电阻率的纳米颗粒软磁薄膜，以寻找GHz频段优秀的电磁噪声抑制材料。发现纳米颗粒膜的噪声抑制作用来源于两种损耗，即磁损耗和电阻损耗（涡流损耗）。本文还发现，将薄膜成分的两种损耗结合起来，可以实现适用于可选电气器件的噪声抑制。低温下薄膜沉积方法的建立：常规溅射沉积时，衬底温度（Tsub.）可达100℃以上，特别是反应溅射时，衬底温度可达300℃左右。如此高的Tsub温度限制了该薄膜的应用领域。我们尝试用面靶溅射系统在低于100℃的条件下寻找沉积方法。系统地研究了溅射参数，发现在沉积过程中Tsub低于85℃。该方法不仅扩展了硅和玻璃的衬底材料，还扩展了低相变温度聚合物或电子器件的衬底材料。实际应用测试：采用2所示的沉积方法在LSI表面溅射沉积纳米颗粒软磁薄膜。我们在沉积过程中没有发现任何机械或电气损伤。用微磁探头法对表面电磁噪声进行了测量。与裸露的LSI相比，在覆盖薄膜的LSI表面观察到相当数量的噪声抑制。所有的研究目标已经实现，如上所述。

1. Investigation of electromagnetic noise suppressor at GHz range : Nano-granular soft magnetic films with different electric resistivity were investigated to find the excellent electromagnetic noise suppressor at GHz band. The noise suppression effect of nano-granular films has been found to originate in two losses, that is, magnetic loss and electric resistive loss (eddy current loss). It is also found that noise suppressor suitable for optional electric devices is realized by combining two losses which is attributed to film compositions.2. Establishment of film deposition method at low temperature : The substrate temperature (Tsub.) increases up to 100 C or more in conventional sputtering deposition, especially, around 300 C in the case of reactive spattering. Such a high temperature of Tsub limits the application field of the film. We have tried to find the deposition method in lower Tsub than 100 C using Facing Targets Sputtering System. Systematically investigating the parameters of sputtering is found to realize Tsub less than 85 C during deposition. The new method expands the substrate materials not only Si and glass but also polymer with low phase transformation temperature or electric devices directly.3. Test for practical application : The nano-granular soft magnetic films were sputter-deposited on the surface of LSI by the deposition method shown in 2. We could not find any mechanical or electrical damage in LSI with the deposition. The electromagnetic noise from the surface has been evaluated by a micro magnetic probe method. Considerable amount of noise suppressing is observed in the surface of LSI covered with the films, compared with the result of nude LSI.All the research objectives have been achieved, described above.