• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.222-225
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• 2001

The planar type inductors have a good potential for the application of miniaturized low power DC-DC converters. For those high quality application, the reduction of coil loss and also magnetic films which have good high frequency properties are required. Fabricated inductor was consisted of FeTaN/Ti magnetic film and electroplated Cu coil thickness of 100$\mu\textrm{m}$ and $SiO_2$ as a insulating layer. The inductor was designed double rectangular spiral shape for magnetic field highly confining within the device. The measured value of inductance and resistance were 980 nH and 1.7 $\Omega$ at 1 MHz as operating frequency of device. The Q factor is 3.55 at 1 MHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.71-71
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• 2009

This paper describes a simple, on-chip CMOS compatible the thin-film inductor applied for the dc-dc converters. A fully CMOS-compatible thin-film inductor with a bottom NiFe core is integrated with the DC-DC converter circuit on the same chip. By eliminating ineffective top magnetic layer, very simple process integration was achieved. Fabricated monolithic thin film inductor showed fairly high inductance of 2.2 ${\mu}H$ and Q factor of 11.2 at 5MHz. When the DC-DC converter operated at $V_{in}=3.3V$ and 5MHz frequency, it showed output voltage $V_{out}=8.0V$, and corresponding power efficiency was 85%.

• Journal of the Korean Magnetics Society
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• v.11 no.6
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• pp.239-244
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• 2001

Recently, RF inductor having researched by many workers, we fabricated and investigated properties of RF inductors. In order to improve the Q-factor (Quality), we try to apply the patterned Fe$_{78.81}$Ta$_{8.47}$N$_{12.71}$ soft magnetic thin film of 5000 which shows magnetic anisotropy of 30 Oe. Thus, patterned magnetic film was artificially increased magnetic anisotropy lead to increasing of ferro-magnetic resonance frequency up to GHz band. Coil as part of inductor was fabricated by lift off process. The dimension of RF inductor was designed 47un, rectangular shape, and measured properties. In the case of Ti/Ag air core type inductor shows Q of 9, inductance of 8.4 nH at 2 GHz. Magnetic film employed inductor shows inductance of 9 nH and FMR resonance frequency was 700 MHz.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.532-538
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• 2000

A double rectangular spiral inductor is fabricated using FeTaN films. The inductor is composed of internal coils sandwiched by magnetic layers. Characteristics of inductor performance are investigated with an emphasis on planarization of magnetic films. In the absence of the planarization process, the grating topology of upper magnetic films over coil arrays degrades the soft magnetic properties and the inductor performance. It also induces a longitudinal magnetic anisotropy with the easy axis aligned to the magnetic flux direction. This alignment prevents the upper magnetic films from contributing to the total induction. Glass bonding is a viable method for achieving a completely planar inductor structure. The planar inductor with glass bonding shows excellent performance : inductance of 1.1 H, Q factor of 7 (at 5 MHz), and the dc current capability up to 100 mA.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.144-144
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• 1999

최근 국내 반도체 기술의 비약적인 발전으로 전자 기기 전반에 소형화, 고주파화, 고기능화 등이 진행되는데 반해, 반도체 소자등에 전원을 공급하거나 회로 전체를 운용하는 전기 신호를 변조.증폭시키는데 반해, 반도체 소자등에 전원을 공급하거나 회로 전체를 운용하는 전기신호를 변조.증폭시키는 인덕터, 트랜스 포머와 같은 수동 자기 소자는 아직도 3차원 벌크 형태로 사용되고 있다. 일본을 중심으로 각국에서는 자기 소자의 박막.소형화에 대한 다각도의 연구가 진행되었으나 국내서는 아직 미미한 실정이다. 따라서 고집적 전원 공급 장치나 지능 센서 등에 반도체와 자기 소자의 사용 주파수 대역과 크기가 통합된 반도체-자성체 IC(semiconductor-magnetic integrated circuit)의 필요성이 절실히 요구되고 있다. 현재 사용중인 벌크형 인덕터나, 트랜스 포머의 경우 10NHz이상의 고주파 대역에는 응용되지 못하고 있다. 이는 적용된 자성체가 페라이트(ferrite)로서 초투자율은 크지만 고주파대역에서의 공진 현상에 의해 저투자율을 나타내고, 포화 자속밀도가 낮기 때문이다. 이러한 페라이트 자성체의 대체품으로 주목받고 있는 것이 Fe, Co계 고비저항 자성마이다. 그러나 Co는 낮은 포화자속밀도를 나타내기 때문에 이러한 조건을 충족시키는 자성막으로 Fe계 미세 결정막을 사용하였다. 본 연구에서는 선택적 전기 도금법(selective electroplating method)과 LIGA like process를 이용하여 공시형 인덕터(air core inductor)의 라이브러리(library)를 구축한 뒤, 고주파 대역에서의 우수한 연자기 특성을 가지는 Ti/FeTaN막을 적용한 자기 박막 인덕터(magnetic thin film inductor)를 제작하여 비교.분석하였다. 제조된 인덕터의 특성 추정은 impedence analyzer를 이용하여 주파수에 따른 저항(resistance), 인덕턴스(inductance)를 측정, 계산한 성능지수(quality factor)로서 인덕터의 성능을 평가하였다. 제조된 박막 인덕터의 코일 형상은 5턴의 double rectangular spiral 구조였으며, 적용된 자성막의 유효 투자율9effective permeability)은 1500, 자성막, 절연막 그리고 코일의 두께는 각각 2$\mu\textrm{m}$, 1$\mu\textrm{m}$, 20$\mu\textrm{m}$이며 코일의 폭은 100$\mu\textrm{m}$, 코일간의 간격은 100$\mu\textrm{m}$였다. 제조된 박막 인덕터는 5MHz에서 1.0$\mu$H의 인덕턴스를 나타내었으며 dc current dervability는 100mA까지 유지되었다.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.107-108
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• 2008

This article describes optimization for PGS(Patterned Ground Shield) of rectangular spiral inductor using Taguchi's Design of Experiment. PGS is decrease method of parasite component by silicon substrate among dielectric loss reduction method. Using taguchi's design of experiment, each parameter is fixed upon that PGS high poison(A), slot spacing(B), strip width(C) and overlap turn number(D) of PGS design parameter. Then we verified that percentage contribution and design sensitivity analysis of each parameter and level by signal to noise ratio of larger-the-better type. We consider percentage contribution and design sensitivity of each parameter and level, and then verify that model of optimization for PGS is lower inductance decreasing ratio and higher Q-factor increasing ratio by EM simulation.

• Journal of the Korean Magnetics Society
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• v.10 no.5
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• pp.250-255
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• 2000

Double rectangular spiral thin-film inductors were fabricated using $Fe_{86.7}Zr_{3.3}B_{4}Ag_{6}$ thin film with high permeability and resistance, in which easy axis of magnetization of the thin-film was perpendicular or parallel to the current direction. The perpendicular geometry inductor revealed higher inductance than the parallel geometry one, because spin aligns of magnetic film were more easily along the field direction due to higher field intensity in the perpendicular geometry. The increase of the inductance, however, resulted in the decrease of resonance frequency. The permeability was monitored by annealing the thin-films at different temperatures. With increasing the permeability, the inductance increased, but total resistance also increased due to the increase in magnetic core loss. As the resonance frequency was higher in air-core inductor than in magnetic thin-film core inductor, it is suggested to increase the resonance frequency that the characteristic of air-core inductor rather than the magnetic properties of the thin-film should be enhanced..

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.573-580
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• 2020

In this paper, the characteristics of the inductor and capacitor, which are the basic components of the circuit, are constructed in a form that can be used in the LTCC multilayer. The inductors and capacitors used for the analysis were designed with rectangular spiral structures and MIM structures inside dielectrics with a dielectric constant of 7, respectively. The measured results were extracted from each element of the equivalent circuit proposed by the curve fitting method and verified the validity of the proposed equivalent circuit based on the extracted results. The analyzed inductor and capacitor were implemented in the form of library and proved its usefulness by applying to Elliptical type 5th LPF design. The LPF was measured through practical production, and as a result, the insertion loss in the passband DC ~ 3.7 GHz was up to 1.0 dB, the return loss was 19.2 dB, and the attenuation in the rejection band was 23.9 dB, which was close to the design goal.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.52-57
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• 2004

In this research, characteristics of air core rectangular spiral type inductors of ㎓ band are numerical analyzed. The basic structure of inductors is a rectangular spiral having 390${\mu}{\textrm}{m}$${\times}$390${\mu}{\textrm}{m}$ size, 5.5 turns, line width of 10 ${\mu}{\textrm}{m}$ and line space of 10 ${\mu}{\textrm}{m}$. Frequency characteristics were simulated up to 10 ㎓. The substrate was modeled as Si, Sapphire, glass and GaAs and the conductor as Cu. The thickness of the conductor was fixed at 2. The number of turns was n.5 to make the input and output terminals to be on the opposite sides. The initial inductance of the basic inductor structure was 13.0 nH, maximum inductance 60.0 nH and resonance frequency 4.25 ㎓. As the dielectric constant of the substrate was increased, the initial inductance varied only slightly, but the resonance frequency decreased considerably. As the number of turns was varied from 1.5 to 9.5, the initial inductance was increased linearly from 2.9 nH to 15.9 nH and, then, saturated at 16.9 nH. The Q factor increased only slightly. The line width and line space of inductors were varied from 5 ${\mu}{\textrm}{m}$ to 20 ${\mu}{\textrm}{m}$, which resulted in the decrease of the initial and maximum inductances. But the resonance frequency was increased. Q factor displayed an increase and a decrease, respectively, when the line width and line space were increased.

• ETRI Journal
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• v.25 no.2
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• pp.65-72
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• 2003

To achieve cost and size reductions, we developed a low cost manufacturing technology for RF substrates and a high performance passive process technology for RF integrated passive devices (IPDs). The fabricated substrate is a conventional 6" Si wafer with a 25${\mu}m$ thick $SiO_2$ surface. This substrate showed a very good insertion loss of 0.03 dB/mm at 4 GHz, including the conductive metal loss, with a 50 ${\Omega}$ coplanar transmission line (W=50${\mu}m$, G=20${\mu}m$). Using benzo cyclo butene (BCB) interlayers and a 10 ${\mu}m$ Cu plating process, we made high Q rectangular and circular spiral inductors on Si that had record maximum quality factors of more than 100. The fabricated inductor library showed a maximum quality factor range of 30-120, depending on geometrical parameters and inductance values of 0.35-35 nH. We also fabricated small RF IPDs on a thick oxide Si substrate for use in handheld phone applications, such as antenna switch modules or front end modules, and high-speed wireless LAN applications. The chip sizes of the wafer-level-packaged RF IPDs and wire-bondable RF IPDs were 1.0-1.5$mm^2$ and 0.8-1.0$mm^2$, respectively. They showed very good insertion loss and RF performances. These substrate and passive process technologies will be widely utilized in hand-held RF modules and systems requiring low cost solutions and strict volumetric efficiencies.