Development of GHz-Drive Magnetic Thin Film Inductors for Integrated Circuits

研制了一种新型的GHz频段磁导仪，以寻找CoNbZr、FeAlO和(CoFeB)SiO_2薄膜材料作为GHz驱动电感的候选材料。还开发了一种提高铁磁共振(FMR)频率的新技术：沿易磁化轴微细加工狭缝，沿硬轴施加稀土磁场。采用本文提出的优化缝隙设计方法，2 GHz的磁损耗可以忽略不计。一个顶部带有0.11.0μm厚淤积CoNbZr薄膜的集成螺旋电感，在2 GHz时，L=8nH，Q=5，尺寸为330×330μm^2。如果在螺旋(夹心式电感)下方和螺旋上安装淤积CoNbZr磁性薄膜，则L=7.9nH，Q=13，尺寸为200×400μm^2。这是值得实现这项工作的主要目标。研制了一种稀土磁近场探头，用于分析从集成电感到半导体电路的漏磁。该探测器在1 GHz处显示了40μm的世界最高空间分辨率。估计对集成电路的电磁干扰可以忽略不计。为了通过铁磁共振损耗来抑制射频在线电磁噪声，已经提出了一种广泛应用的集成铁磁薄膜。在1 GHz下的插入损耗仅为0.4db，而在20 GHz时的插入损耗达到15db，从而为铁磁集成电感的实用化提供了可能性，并开辟了一个新的技术领域--“在GHz范围内的IT软磁应用”。首届和第二届“高频微磁器件和材料”国际研讨会已经由研究人员发起。

A new GHz-band permeameter has been developed to find out the CoNbZr, FeAlO and (CoFeB)SiO_2 Thin-film materials as the possible candidates for GHz-drive inductors. A new technique on raise the ferromagnetic resonance (FMR) frequency has also been developed; Microfabricate narrow slits along the easy axis of magnetization and apply RE magnetic field along the hard axis. Then magnetic losses at 2GHz can be negligible through the optimum slit design method we established.An integrated spiral inductor with 0.1-1.0μm-thick silted CoNbZr film on the top exhibited L=8nH and Q=5 at 2GHz, Its size was 330x330μm^2. Provided that the silted CoNbZr magnetic film are installed below and on the spiral (sandwich type inductor), L=7.9nH and Q=13 has been achieved is the 200x400μm^2 size. This is worth achieving main objective of this work.An RE magnetic near field probe has been developed to analyze leakage flux from the integrated inductor to semiconductor circuit. The probe exhibited world-highest spatial resolution of 40μm at 1GHz. It is estimated that the electromagnetic interference to the integrated circuit would be negligible.An extensive application of integrated ferromagnetic film has been proposed to suppress RF in-line electromagnetic noise by means of FMR losses. Insertion loss at 1GHz was only 0.4dB while is reached 15dB as 20GHz.Thus this work has been concluded, showing a practical possibility of ferromagnetic integrated inductors as well as to pioneering a new technology field of "soft magnetic applications in the GHz range for IT." The first and second international symposium on "High Frequency Micromagnetic Devices and Materials" has been initiated by the investigators.