• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1435-1437
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• 2005

An integrated inductor using the low temperature cofiring ceramics(LTCC) NiZnAg was fabricated. The inductor has a sandwitch structure, which consists of 18 turns-and-thin Ag rectangular spiral coils in 2-layers(10-turn & 8-turn in each layer). The two layers of Ag coils are among three thick Ni-Zn ferrite so the inductor has a dimension of 12.70mm$\times$12.70mm and 0.32mm thick. For the fabricated inductor, calculation method of inductance was given and it is confirmed that the calculated value is very close to the measured one. Finally as an application of the LTCC integrated inductor for low power electronic circuits, a LTCC boost DC/DC converter with 1W output power and 500KHz switching frequency using the inductor fabricated was developed. For the converter the maximum efficiency of about 87% was obtained.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.25-35
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• 1999

LTCC (Low Temperature Cofired Ceramic) or LTCC-M (Low Temperature Cofired ceramic on Metal) technology is one of MCM-C (Multichip Module on Ceramic) technologies and becomes to be widely used in consumer, RF and automotive electronics. As green sheets for LTCC are cofired below $1000^{\circ}C$ in comparison with those for HTCC (High Temperature Cofired Ceramic), high conductivity metal traces such as gold, silver and copper can be used. The dimensional stability in LTCC-M technology enables embedded passives to be integrated inside modules, which enhances the electrical performance and increases the reliability of the modules. Coefficient of thermal expansion and dielectric constant can be controlled by changing composition and heating profile for cofiring. In this technical review, LTCC and LTCC-M technologies are introduced and advantages of those technologies are explained.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1299-1300
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• 2007

In this study, low temperature sintering property of (1-x)$TiTe_{3}O_{8}-xMgTiO_{3}$ ceramics were investigated for LTCC application which enable to cofiring with Ag electrode. $TiTe_{3}O_{8}$ mixed with $MgTiO_3$ to improve the temperature property. In the X-ray diffraction patterns, the columbite structure of $TiTe_{3}O_{8}$ phase and ilmenite structure of $MgTiO_3$ phase were coexisted in all specimens. The bulk densities and dielectric constants were decreased with increasing of $MgTiO_3$. However, the quality factors were increased with $MgTiO_3$ addition. Also, TCRF was shifted to negative(-) direction. Microwave dielectric properties of (1-x)$TiTe_{3}O_{8}-xMgTiO_{3}$ ceramics had similar tendency with calculated value by the mixing rule. The dielectric constant, quality factor and TCRF of $05TiTe_{3}O_{8}-0.5MgTiO_{3}$ ceramics sintered at $830^{\circ}C$ for 3h. were 26.19, 43,290GHz and $-3.9ppm/^{\circ}C$, respectively.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.169-170
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• 2008

In this study, low temperature sintering property of the $0.6TiTe_3O_8-0.4MgTiO_3$ ceramics with sintering adds were investigated for LTCC application which enable to cofiring with Ag electrode. $TiTe_3O_8$ mixed with $MgTiO_3$ to improve the temperature property. In the X-ray diffraction patterns, the columbite structure of $TiTe_3O_8$ phase and ilmenite structure of $MgTiO_3$ phase were coexisted in all specimens. In the case of SnO addition, the bulk density and dielectric constant were increased but quality factor was decreased with amount of SnO additions. The TCRF of the $0.6TiTe_3O_8-0.4MgTiO_3$+xwt%SnO ceramics were shifted to negative direction. The dielectric constant, quality factor and TCRF of the $0.6TiTe_3O_8-0.4MgTiO_3$ ceramics with 2.5wt% addition of SnO sintered at $830^{\circ}C$ for 1hr were 29.86, 35,800 GHz, -0.58 ppm/$^{\circ}C$, respectively.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.114-115
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• 2007

In this study, low temperature sintering property of the $0.6TiTe_3O_8-0.4MgTiO_3$ ceramics with sintering adds were investigated for LTCC application which enable to cofiring with Ag electrode. $TiTe_3O_8$ mixed with $MgTiO_3$ to improve the temperature property. In the X-ray diffraction patterns, the columbite structure of $TiTe_3O_3$ phase and ilmenite structure of $MgTiO_3$ phase were coexisted in all specimens. In the case of $H_3BO_3$ addition, the bulk density and dielectric constant were decreased but quality factor was increased with amount of $H_3BO_3$ additions. The TCRF of the $0.6TiTe_3O_8-0.4MgTiO_3+xwt%H_3BO_3$ ceramics were moved to positive direction. In another case, SnO addition, the bulk density and dielectric constant were increased but Quality factor was decreased with amount of SnO additions. The TCRF of the $0.6TiTe_3O_8-0.4MgTiO_3$+ywt%SnO ceramics were shifted to negative direction. The dielectric constant, quality factor and TCRF of the $0.6TiTe_3O_8-0.4MgTiO_3$ ceramics with $2wt%H_3BO_3$ and 2.5wt%SnO sintered at $830^{\circ}C$ for 1h, were 28.5, 39,570GHz, $+9.34ppm/^{\circ}C$ and 29.86, 35,80000z, $-0.58ppm/^{\circ}C$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.628-631
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• 2003

In this paper, 2.4 GHz WLAN BPF(Band Pass Filter) using LTCC(Low temperature cofiring ceramic) multilayer technology was simulated and manufactured. A modified ${\lambda}/4$ Hair-pin resonator with shunt-to ground loaded capacitor is used to shorten resonator length and improve circuit Q factor. Proposed BPF has a combline structure. Electro-magnetic Coupling between coupled strip-line resonators is controlled to provide attenuation poles at finite frequencies. The overall size of the filter is $3.2{\times}1.6{\times}1.3mm^3$. The measured result shows good agreement with simulated data.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.7-12
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• 2002

In the measurement of the RF properties, the LTCC substrate must be considered as a system including various conductor patterning processes. In this paper, the LTCC substrate system is compared with a conventional PCB(Printed Circuit Board) substrate such as FR-4, Duroid and Teflon, etc. The microstrip resonator method is employed for the measurement of the RF properties in the range of DC to 20 GHz. Experimental results show that the ring resonator method is suitable for system loss measurement, and the series gap resonator method for dielectric constant measurement. The process of conductor patterning and its effect on the system loss were also studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.267-268
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• 2007

기존의 Free Sintering 방법을 사용하는 LTCC(Low Temperature Cofiring Ceramics)는 수축률이 일정하지 않아서 설계 치수와 동일하게 제작하기 어려운 단점을 가지고 있다. 이에 따라서 정밀한 전자부품을 제작하기 위한 방안으로 X-Y면 방향에서의 변형을 거의 zero로 제어하는 Constrained Sintering(CS) 기술이 요구되고 있다. 본 연구에서는 LTCC 기판이 소성되는 동안에 변형을 억제하기 위하여 소성온도가 LTCC 기판 보다 높은 $Al_2O_3$ 분말과 유기물을 혼합하여 페이스트를 제작한 후에 스크린 프린팅 방법을 이용하여 도포 후에 Z축 방향으로 일축가압을 하면서 소성하여 수축률을 제어 하였다. 또한 바인더와 $Al_2O_3$ 분말의 함량에 대한 최적 조성의 $Al_2O_3$ 페이스트를 제작하여 0.5%로 수축률을 가지는 균일한 LTCC 기판을 구현 할 수 있었다.