• Korean Journal of Materials Research
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• v.18 no.2
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• pp.69-72
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• 2008

A sensor element array for combinatorial solution deposition research was fabricated using LTCC (Low-temperature Co-fired Ceramics). The designed LTCC was co-fired at $800^{\circ}C$ for 1 hour after lamination at $70^{\circ}C$ under 3000 psi for 30 minutes. $SnO_2$ sol was prepared by a hydrothermal method at $200^{\circ}C$ for 3 hours. Tin chloride and ammonium carbonate were used as raw materials and the ammonia solution was added to a Teflon jar. 20 droplets of $SnO_2$ sol were deposited onto a LTCC sensor element and this was heat treated at $600^{\circ}C$ for 5 hours. The gas sensitivity ($S\;=\;R_a/R_g$) values of the $SnO_2$ sensor and 0.04 wt% Pd-added $SnO_2$ sensor were measured. The 0.04 wt% Pd-added $SnO_2$ sensor showed higher sensitivity (S = 8.1) compared to the $SnO_2$ sensor (S = 5.95) to 200 ppm $CH_3COCH_3$ at $400^{\circ}C$.

• Transactions of Materials Processing
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• v.16 no.5 s.95
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• pp.396-400
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• 2007

LTCC(Low Temperature Co-fired Ceramic) which offers a good performance to produce multilayer structures with electronic circuits and components has emerged as an attractive technology in the electronic packaging industry. In LTCC module fabrication process, the lamination and the sintering are very important processes and affect the electrical characteristics of the final products because the processes change the permittivity of ceramics and the dimension of the circuit patterns which have influences on electronic properties. This paper discusses the influence of lamination pressure and sintering temperature on the permittivity and the dimensional change of LTCC products. In the present investigation, it is shown that the permittivity increases along with increasing of the lamination pressure and the sintering temperature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.67-70
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• 2007

LTCC (Low Temperature Co-fired Ceramic) has been emerged as a promising technology in packaging industry. In this technology the lamination and the sintering process are very important because they change the permittivity of ceramics and the dimension of metal pattern which have influences on electric property. In this paper we studied on influence of the permittivity and the dimension change by lamination pressure and sintering temperature of LTCC process. As a results, permittivity increase along with increasing of lamination pressure and sintering temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.365-365
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• 2008

In this work, Ga-doped ZnO (GZO) thin films for NOx gas sensor application were deposited on low temperature co-fired ceramics (LTCC) substrates, by RF magnetron sputtering method. The LTCC substrate is one of promising materials for this application since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.). The LTCC substrates with thickness of 400 pm were fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The structural properties of the fabricated GZO thin films with different thickness are analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The GZO gas sensors are tested by gas measurement system under varing operation temperature and show good performance to the NOx gas in sensitivity and response time.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.11a
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• pp.57-57
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• 2000

Brazing characteristics of the LTCC(Low Temperature Co-fired Ceramics)/ Kovar(Fe-Ni-Co alloy) was investigated. Kovar is one of the typical material for the lid of MCM and packages. In case of alumina package, Brazing process is done by higher temperature profile than 800 $^{\circ}C$ and Ag-Cu alloy. But, LTCC has sintering temperature near 850 $^{\circ}C$. So, it is difficult to use the same process as alumina brazing. The adhesion strength of the brazed part is affected by brazing alloy and metallization properties between conductor pattern and LTCC material. We investigated brazing characteristics of the LTCC/Kovar using various brazing alloys(Ag-Cu, Au-Sn) and process conditions. And, we examined the influence of the glass contents in conductor on the brazing characteristics of the LTCC/Kovar.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.551-552
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• 2006

The miniature fuel cells have emerged as a promising power source for applications such as cellular phones, small digital devices, and autonomous sensors to embedded monitors or to micro-electro mechanical system (MEMS) devices. Several chemicals run candidate at a fuel in those systems, such as hydrogen. methanol, ethanol, acetic acid, and di-methyl ether (DME). Among them, hydrogen shows most efficient fuel performance. However, there are some difficulties in practical application for portable power sources. Therefore, more recently, there have been many efforts for development of micro-reformer to operate highly efficient micro fuel cells with liquid fuels such as methanol, ethanol, and DME In our experiments, we have integrated a micro-fuel processor system using low temperature co-fired ceramics (LTCC) materials. Our integrated micro-fuel processor system is containing embedded heaters, cavities, and 3D structures of micro- channels within LTCC layers for embedding catalysts (cf. Figs. 1 and 2). In the micro-channels of LTCC, we have loaded $CuO/ZnO/Al_2O_3$ catalysts using several different coating methods such as powder packing or spraying, dipping, and washing of catalyst slurry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.499-502
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• 2008

In this work, Ga-doped ZnO (GZO) thin films for gas sensor application were deposited on low temperature co-fired ceramics (LTCC) substrates, by RF magnetron sputtering method. The LTCC substrate is one of promising materials for this application since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.). The LTCC substrates with thickness of $400\;{\mu}m$ were fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The structural properties of the fabricated GZO thin film with thickness of 50 nm is analyzed by X-ray diffraction method (XRD) and field emission scanning electron microscope (FESEM). The film shows good adhesion to the substrate. The GZO gas sensors are tested by gas measurement system and show fast response and recovery characteristics to $NO_x$ gas that is 27.2 and 27.9 sec, recpectively.

• Journal of the Korean Ceramic Society
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• v.44 no.5 s.300
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• pp.173-178
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• 2007

The microstructure and microwave dielectric properties of dolomite type borates, $CaZr(BO_3)_2$ ceramics prepared by conventional mixed oxide method were explored. The sintering temperature of $CaZr(BO_3)_2$ ceramics could be reduced from $1150^{\circ}C\;to\;925^{\circ}C$ with little amount of sintering additives. Microwave dielectric properties of 3 wt% $Bi_2O_3-CuO$ added $CaZr(BO_3)_2$ ceramics sintered at $925^{\circ}C$ were $K{\approx}10.4,\;Q{\times}f{\approx}80,000GHz\;and\;TCF{\approx}+2ppm/^{\circ}C$. Thus obtained LTCC tape was co-fired with Ag paste for compatibility test and revealed no sign of Ag reaction with the ceramics. Therefore, $CaZr(BO_3)_2$ ceramics is considered as a possible candidate material for low temperature co-fired multilayer devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.215-218
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• 2011

A novel design of gas sensor using Ga-doped ZnO (GZO) thin films which are deposited on low temperature co-fired ceramic (LTCC) substrates is presented. The LTCC substrates with thickness of 400 ${\mu}m$ are fabricated by laminating 12 green tapes which consist of alumina and glass particle in an organic binder. The GZO thin films with different thickness are deposited on LTCC substrates, by RF magnetron sputtering method. The microstructure and sensing properties of GZO gas sensing films are analyzed as a function of the film thickness. The films are well crystallized in the hexagonal (wurzite) structure with increasing thickness. The maximum sensitivity of 3.49 is obtained at 100 nm film thickness and the fastest 90% response time of 27.2 sec is obtained at 50 nm film thickness for the operating temperature of $400^{\circ}C$ to the $NO_2$ gas.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.245-248
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• 2012

In this paper, the optimized growing conditions of PZT thin films on low temperature co-fired ceramics (LTCC) substrates are studied. The LTCC technology is an emerging one in the fields of mesoscale (from 10 um to several hundred um) sensor and actuator against silicon based technology due to low cost, high yield, easy manufacturing of 3 dimensional structure, etc. The LTCC substrates with thickness of 400 um are fabricated by laminating 100 um green sheets using commercial power (NEG, MLS 22C). The Pt/Ti bottom electrodes are deposited on the LTCC substrates, then the growing conditions of PZT thin films using rf magnetron sputtering method are studied. The growing conditions are tested under various rf power and gas ratio of oxygen to argon. And the crystallization and ingredient of PZT films are analyzed by X-ray diffraction method (XRD) and energy dispersive spectroscopy (EDS). The optimized growing conditions of PZT thin films are rf power of 125W, Ar/O2 gas ratio of 15:5.