• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.30-32
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• 2005

This paper reports on an LTCC-based packaging method using Au/Sn eutectic bonding process for RF MEMS applications. The proposed packaging structure was realized by a micromachining technology. An LTCC substrate consists of metal filled vertical via feedthroughs for electrical interconnection and Au/Sn sealing rim for eutectic bonding. The LTCC capping substrate and the glass bottom substrate were aligned and bonded together by a flip-chip bonding technology. From now on, shear strength and He leak rate will be measured then the fabricated package will be compared with the LTCC package using BCB adhesive bonding method which has been researched in our previous work.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.271-275
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• 2008

The MAM(Megasonic Agitated Module) has been fabricated for improving the characteristics of wet etching. The characteristics of the MAM are investigated during the wet etching with and without megasonic agitation in this paper. The adoption of the MAM has improved the characteristics of wet etching, such as the etch rate, etch uniformity, and surface roughness. Especially, the etching uniformity on the entire wafer was less than ${\pm}1%$ in both cases of Si and glass. Generally, the initial root-mean-square roughness($R_{rms}$) of the single crystal silicon was 0.23nm. Roughnesses of 566nm and 66nm have been achieved with magnetic stirring and ultrasonic agitation, respectively, by some researchers. In this paper, the roughness of the etched Si surface is less than 60 nm. Wet etching of silicon with megasonic agitation can maintain nearly the original surface roughness during etching. The results verified that megasonic agitation is an effective way to improve etching characteristics of the etch rate, etch uniformity, and surface roughness and that the developed micromachining system is suitable for the fabrication of devices with complex structures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.3
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• pp.705-711
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• 2000

A thin film oxide semiconductor micro gas sensor array which shows only 60 mW of power consumption at an operating temperature of $300^{\circ}C$ has been fabricated using microfabrication and micromachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double-layer structure of $0.1\mum\; thick\; Si_3N_4 \;and\; 1 \mum$ thick phosphosilicate glass (PSG) prepared by low-pressure chemical-vapor deposition (LPCVD) and atmospheric-pressure chemical-vapor deposition (APCVD), respectively. The sensor array consists of such thin film oxide semiconductor sensing materials as 1 wt.% Pd-doped $SnO_2,\; 6 wt.% A1_2O_3-doped\; ZnO,\; WO_3$/ and ZnO. Baseline resistances of the four sensing materials were found to be stable after the aging for three days at $300^{\circ}C$. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.408-413
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• 1996

A self-diagnostic, air-damped, piezoresitive, cantilever-beam microaccelerometer has been designed, fabricated and tested for applications to automotive electronic airbag systems. A skew-symmetric proof-mass has been designed for self-diagnostic capability and zero transverse sensitivity. Two kinds of multi-step anisotropic etching processes are developed for beam thickness control and fillet-rounding formation, UV-curing paste has been used for sillicon-to-glass bounding. The resonant frequency of 2.07kHz has been measured from the fabricated devices. The sensitivity of 195 $\mu{V}$/g is obtained with a nonlinearity of 4% over $\pm$50g ranges. Flat amplitude response and frequency-proportional phase response have been obserbed, It is shown that the design and fabricaiton methods developed in the present study yield a simple, practical and effective mean for improving the performance, reliability as well as the reproducibility of the accelerometers.