Self-Heating CMOS Flow Sensor

Waikhom, Reshmi; Yang, Lung‐Jieh; Shih, Horng-Yuan; Kuo, Cai-Rong

doi:10.1109/transducers50396.2021.9495463

Cited by 2 publications

(8 citation statements)

References 9 publications

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“…At the heart of sensor products is the CMOS technology using the latest TSRI/UMC 0.18 µm single-poly-six-metal (1P6M) process, which enables us to combine the sensor component with amplifier circuitry on a tiny CMOS silicon chip. The CMOS MEMS technology provides error-free gas flow metering that remains stable over a long period and generates a fast and high-precision sensor signal, recently [93][94][95][96][97]. Figure 2a shows the UMC 0.18 µm CMOS process proceeded with isotropic XeF 2 undercut etching for the MEMS open area; Figure 2b shows the use of shallow-trench-isolation (STI) to protect polysilicon during the etching process.…”

Section: Educational Cmos Foundry Service Provided By Tsrimentioning

confidence: 99%

“…Figure 5a shows the CMOS standard process, which is composed of four kinds of different thin films including silicon nitride (Si3N4), silicon dioxide (SiO2), aluminum, and polysilicon on the silicon substrate. The arrangements of thin films in the order from bottom to top are silicon substrate, silicon dioxide, multiple metal layers with their inter-layer for bulk micromachining [91,165]; (c) acid etch metals (surface micromachining) [35,37]; (d) deep trench plasma etching the oxides to release the cantilever [130]; (e) acid is used to etch metals and TMAH used to etch the Si substrate [57]; (f) electroplating Ni in the process (c) [90,137]; (g) parylene or gelatin is coated on process (e) [87,88]; (h) anisotropic and isotropic etching with STI protection [96,97,102,166].…”

Section: Post-processes Of Cmos Mems Devicesmentioning

confidence: 99%

“…The detailed explanation has been given in Figures 2-4. STI oxide is used to protect polysilicon during XeF 2 etching [96,97,102,122].…”

Section: Post-processes Of Cmos Mems Devicesmentioning

confidence: 99%

“…In the following, the authors took the flow sensor design as an example to verify the CMOS MEMS process of Figure 6. The work builds on a fabrication process reported at Transducers-2021 [96], revealing that CMOS MEMS technology can generate minimal space utilization micromachined flow sensors. The flow sensor was designed with a selfheating half-bridge RTD or a hot wire that did not use any heater during the operation.…”

Section: Cmos Mems Sensor Design Flowmentioning

confidence: 99%

“…The self-heating voltage V 0 is no more a noise, but the bias to the RTD half bridge is necessary for the device operation. Resistor R 1 is on the substrate, and R 2 is on the MEMS cavity or the free standing plate region, which provides good thermal isolation [96]. T 1 is the local temperature on the substrate, and T 2 is on the MEMS cavity with air gap underneath, accordingly.…”

Section: Flow Sensor Designmentioning

confidence: 99%

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Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

et al. 2022

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The complementary metal-oxide-semiconductor (CMOS) process is the main stream to fabricate integrated circuits (ICs) in the semiconductor industry. Microelectromechanical systems (MEMS), when combined with CMOS electronics to form the CMOS MEMS process, have the merits of small features, low power consumption, on-chip circuitry, and high sensitivity to develop microsensors and micro actuators. Firstly, the authors review the educational CMOS MEMS foundry service provided by the Taiwan Semiconductor Research Institute (TSRI) allied with the United Microelectronics Corporation (UMC) and the Taiwan Semiconductor Manufacturing Company (TSMC). Taiwan’s foundry service of ICs is leading in the world. Secondly, the authors show the new flow sensor integrated with an instrumentation amplifier (IA) fabricated by the latest UMC 0.18 µm CMOS MEMS process as the case study. The new flow sensor adopted the self-heating resistive-thermal-detector (RTD) to sense the flow speed. This self-heating RTD half-bridge alone gives a normalized output sensitivity of 138 µV/V/(m/s)/mW only. After being integrated with an on-chip amplifier gain of 20 dB, the overall sensitivity of the flow sensor was measured and substantially improved to 1388 µV/V/(m/s)/mW for the flow speed range of 0–5 m/s. Finally, the advantages of the CMOS MEMS flow sensors are justified and discussed by the testing results.

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Section: Educational Cmos Foundry Service Provided By Tsrimentioning

confidence: 99%

Section: Post-processes Of Cmos Mems Devicesmentioning

confidence: 99%

“…The detailed explanation has been given in Figures 2-4. STI oxide is used to protect polysilicon during XeF 2 etching [96,97,102,122].…”

Section: Post-processes Of Cmos Mems Devicesmentioning

confidence: 99%

Section: Cmos Mems Sensor Design Flowmentioning

confidence: 99%

Section: Flow Sensor Designmentioning

confidence: 99%

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Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

et al. 2022

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Soap Film Visualization of a 10 cm-Span Flapping Wing

Yang

Tasupalli

Waikhom

et al. 2021

Fluids

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Flapping wing micro-air-vehicles (FWMAVs) animate the small-space dexterous flight, hovering, and energy-saving characteristics of birds and insects, and are believed to have enlightenment for the development of bionic flight in the future. When designing FWMAVs, detailed unsteady aerodynamic information is required. Besides the computational fluid mechanics (CFD) technology study, the flow visualization is also needed to assist this research. This article innovatively used soap film visualization with high-speed photography to record two kinds of the 2D flow fields laterally and longitudinally, respectively, generated by a flapping wing of 10 cm span. Different from the qualitative comparison of soap film imaging with the conventional smoke tracing method, the subsequent processing of the soap film images was demonstrated. This work explains how to quantify the soap film imaging into lift and thrust forces, and the corresponding results are compared with the wind tunnel force measurement data preliminarily.

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Self-Heating CMOS Flow Sensor

Cited by 2 publications

References 9 publications

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

Soap Film Visualization of a 10 cm-Span Flapping Wing

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