Browsing by Author "Wu, Chia-Yu"

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A CMOS MEMS Audio Transducer Implemented by Silicon Condenser Microphone With Analog Front-End Circuits of Audio Codec
(2012-09-01)
Chiang, Cheng-Ta
;
Wang, Chih-Hsien
;
Wu, Chia-Yu
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電機學院
;
College of Electrical and Computer Engineering
This study proposes a CMOS MEMS audio transducer implemented by combining a silicon condenser microphone with analog front-end audio codec circuits. The proposed CMOS MEMS audio transducer is attractive because the sensor and all the circuits are robustly and compactly integrated. The overall size of the proposed device is much smaller than traditional electrets-condenser microphones (ECMs). Another innovation of the proposed CMOS MEMS audio transducer is that it can operate without any charge pump circuits, which overcomes the problem of requiring a high bias voltage. Measurement results confirm the correct functions and performance of the proposed CMOS MEMS audio transducer. The area of the proposed CMOS MEMS audio transducer is 1352 x 1410 mu m(2) and the FOM of the proposed sigma-delta modulator is 148 dB. The proposed CMOS MEMS audio transducer is suitable for audio devices, such as audio codecs.
Evaluation of the thermal conductance of flip-chip bonding structure utilizing the measurement based on Fourier's law of heat conduction at steady-state
(2018-06-01)
Wu, Chia-Yu
;
Huang, Yin-Hsien
;
Wu, Hsin-Han
;
Hsieh, Tsung-Eong
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材料科學與工程學系
Fourier's law of heat conduction at steady-state was adopted to establish a measurement method utilizing platinum (Pt) thin-film electrodes as the heater and the temperature sensor. The thermal conductivities (kappa's) of Pyrex glass, an epoxy resin and a commercial underfill for flip-chip devices were measured and a good agreement with previously reported values was obtained. The thermal boundary resistances (R-TBR 's) of Pt/sample interfaces were also extracted for discussing their influence on the thermal conduction of samples. Afterward, the flip-chip samples with 2x2 solder joint array utilizing Si wafers as the die and the substrate, without and with the underfills, were prepared and their thermal conductance were measured. For the sample without underfill, the air presenting in the gap of die and the substrate led to the poor thermal conductance of sample. With the insertion of underfills, the thermal conductance of flip-chip samples improved. The resistance to heat transfer across Si/underfill interfaces was also suppressed and to promote the thermal conductance of samples. The thermal properties of underfill and R-TBR at Si/underfill interface were further implanted in the calculation of thermal conductance of flip-chip samples containing various solder joint arrays. The increasing number of solder joints diminished the influence of thermal conduction of underfill and R-TBR of Si/underfill interface on the thermal conductance of samples. The insertion of underfill with high-kappa value might promote the heat conductance of samples containing low-density solder joint arrays; however, it became insignificant in improving the heat conductance of samples containing high-density solder joint arrays. (C) 2018 Author(s).