• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.143-146
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• 2002

A multilayer two-stage bandpass filter using dissimilar low-temperature cofired-ceramic (LTCC) materials is proposed in this paper. The proposed bandpass filter is composed of ceramic substrates with different dielectric constant instead of single ceramic material from top to bottom layer. Inductive elements are designed in a low permittivity ceramic layer to reduce parasitic effects and loss, while capacitive elements are designed in a high pertimitivity ceramic layer for size reduction. The center frequency of the proposed filter is 1.842 GHz, and the performance of the filter is analyzed and compared with the conventional LTCC filter with single material in terms of integration density, size reduction, and performance improvement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.273-276
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• 2003

본 논문에서는 한쪽이 단락된 스트립선로(Stripline)와 Loading 캐패시턴스(Capacitance)로 구성된 새로운 형태의 1/4파장 스트립선로 공진기를 제안하였으며, 이 공진기를 이용해서 5.2 GHz 대역 무선 LAN용 적층 대역통과 여파기를 설계, 제작 하였다. 제안한 공진기의 전파지연효과(Slow-wave Effect) 때문에, 기존의 공진기에 비해서 길이가 축소되며, 기준 공진주파수(Fundamental Resonant Frequency)에 대한, 첫 번째 기생공진주파수(First Spurious Resonant Frequency) 값이 커지기 때문에, 넓은 상향저지대역(Wide Upper Stopband)을 갖는 초소형의 대역통과 여파기의 설계가 가능하다. 설계한 여파기를 LTCC 적층 공정 기술을 이용하여 제작하였으며 그 크기는 $3.2mm{\times}1.6mm{\times}0.8mm$ 이다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.4
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• pp.344-348
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• 2002

As microelectronics technology continues to progress, there is also a continuous demand on highly integration and miniaturization of systems. For example, it is desirable to package several integrated circuits together in multilayer structure, such as multichip modules, to achieve higher levels of compactness and higher performance. Passive components (i.e., capacitors, resistors, and inductors) are very important fort many MCM applications. In addition, the low-temperature co-fired ceramic (LTCC) process has considerable potential for embedding passive components in a small area at a low cost. In this paper, we investigate a method of statistically modeling integrated passive devices from just a small number of test structures. A set of LTCC inductors is fabricated and their scattering parameters (s-parameters) are measured for a range of frequencies from 50MHz to 5GHz. An accurate model for each test structure is obtained by using a building block based modeling methodology and circuit parameter optimization using the HSPICE circuit simulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.298-299
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• 2006

공통의 glass를 이용한 LTCC 이종소재의 무수축 접합 가능성을 확인하기 위하여 2종의 상용 glass를 이용하여 소결온도를 변화시키면서 미세구조 및 결정구조, x-y축 방향의 수축율을 관찰하였다. 실험 결과 GA-12 glass는 강유전체 $BaTiO_3$와 glass의 composite개념을 이용한 접합에 적절하지 않은 것으로 판단되었으며, GA-1 glass의 경우는 $750^{\circ}C$와 $800^{\circ}C$ 사이에서 glass의 충분한 침투조건이 확인되며, 결정구조 에서도 glass/$BaTiO_3$ composite이 형성되므로 layer 간의 delamination은 발견되지만 x-y축 방향의 무수축 접합의 가능성이 확인되었다.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.39-43
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• 2003

Thermal management is very important for the success of high density circuit design in LTCC. In this paper, LTCC substrates containing thermal via and pad were fabricated in order to study the influence of the thermal dissipation. To realize the accurate thermal analysis for structure design, a series of simple thermal conductivity measurement by laser flash method and parametric numerical analysis have been carried out. The LTCC substrate including via and Ag pad has good thermal conductivity over 103 W/mK which is 44% value of pure Ag material. Thermal behaviors with via arrays, size and density in the LTCC substrate were studied by numerical method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.864-868
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• 2010

Among LTCC material for substrate, the crystallized anorthite system was mainly studied as high strength material. However, specific factors that have affected on strength of material were studied insufficiently on anorthite system. In this study, the composition of anorthite glass was Ca-Al-Si-Zn-O. The changes of phase and microstructure were observed with the amount and the particle size of glass and the sintering temperature. It was studied that the factors affected on the strength of material. Phases of anorthite and $ZnAl_2O_4$ were formed with the increase of sintering temperature. The $Al_2O_3$ phase was increased with $Al_2O_3$ amount, acted as filler, and the strength of material is increased with $Al_2O_3$ phase. But phases of anorthite and $ZnAl_2O_4$ didn't affect on the strength of material. In the case of 60 vol% glass amounts and below $3.2\;{\mu}m$ of glass particle size, the strength of material was decreased. It is thought that the decrease of strength was due to non-homogeneous mixing between glass powder and filler.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.04b
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• pp.33.2-33.2
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• 2004

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.12-24
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• 2001

The key advantage of LTCC(low temperature co-fired ceramics) technology is the ability to integrate passive components such as resistors, capacitors, and inductors. More compact circuits with an increased scale of integration are needed with the development for advanced telecommunication system such as IMT-2000. LTCC technology can be obtained by removing these elements from the substrate surface to inside of ceramic body. And it can miniaturize the wireless phone through integration of planar patch antenna, duplexer, band pass filter, bias line, circuit of impedance matching and RF choke etc. Futhermore, with the multilayer chip process and its outstanding electrical material characteristics, LTCC is predestined for highly-integrated, cost effective wide band applications. This paper focuses on the general description of LTCC MCM technologies and the fabrication of the multilayer VCO module.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.5-8
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• 2009

In this paper, a high-quality low-temperature co-fired ceramic (LTCC) solenoid inductor using a solder ball and an air cavity on a silicon wafer for three-dimensional (3-D) system-in-package (SiP) is proposed. The LTCC multi-layer solenoid inductor is attached using Ag paste and solder ball on a silicon wafer with the air cavity structure. The air cavity is formed on a silicon wafer through an anisotropic wet-etching technology and is able to isolate the LTCC dielectric loss which is equivalent to a low k material effect. The electrical coupling between the metal layer and the LTCC dielectric layer is decreased by adopting the air cavity. The LTCC solenoid inductor using the solder ball and the air cavity on silicon wafer has an improved Q factor and self-resonant frequency (SRF) by reducing the LTCC dielectric resistance and parasitic capacitance. Also, 3-D device stacking technologies provide an effective path to the miniaturization of electronic systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.751-755
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• 2003

In this paper, We proposed compact multi-layer LTCC (Low Temperature Cofired Ceramic) bandpass filter for Bluetooth module. A ${\lambda}/4$ coupled stripline resonators are designed, which composed of coupled strip-line section and loading capacitance. This resonator with a loading capacitor has slow-wave characteristics. Due to the slow-wave effect of the proposed resonator, it is possible to design and fabricate a compact bandpass filter with a wide upper stop band. Attenuation poles in the lower stop band are achieved using controlling of electro-magnetic coupling between resonators. Using multi-layer LTCC technology, we designed and fabricated band pass filter with a finite attenuation pole and wide upper stopband. The overall size of the filter is $1.2{\times}2.0{\times}1.0mm^3$.