Sapphire-based capacitance diaphragm gauge for high temperature applications

Ishihara, Takuya; Sekine, Matsuo; Ishikura, Yuki; Kimura, Syo; Harada, H.; Nagata, M.; Masuda, Takashi

doi:10.1109/sensor.2005.1496464

Cited by 10 publications

(5 citation statements)

References 2 publications

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“…Sapphire wafer direct bonding by hydrophilic wafer bonding was also examined; high-temperature annealing (>800 °C) is necessary. [38][39][40] Considering alkali gas cell fabrication and other applications in MEMS packaging, a simple, high-throughput, and low-temperature bonding process in gas ambient is required.…”

Section: Introductionmentioning

confidence: 99%

Surface activated room-temperature bonding in Ar gas ambient for MEMS encapsulation

Takagi

Kurashima

2017

Jpn. J. Appl. Phys.

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Surface activated room-temperature bonding of Si and sapphire wafers in high-purity inert gas ambient was examined. Although surface activated bonding has been mainly performed in high vacuum, Si and sapphire wafers were successfully bonded in Ar gas ambient up to 90 kPa, which is almost atmospheric pressure. The dicing test proved that the bonding prepared in Ar gas ambient was strong enough for MEMS packaging, although the bonding strength was slightly decreased compared with that prepared in vacuum. Transmission electron microscope observation revealed that the bonding interface prepared in Ar gas ambient is almost the same as that prepared in vacuum. It means that Ar atoms in the bonding ambient do not hamper the interatomic bond formation at the bonding interface. Room-temperature bonding in gas ambient enables hermetic packaging of MEMS devices, such as inertia sensors, MEMS switches, and Cs vapor cells for MEMS atomic clocks at various pressures.

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Section: Introductionmentioning

confidence: 99%

Surface activated room-temperature bonding in Ar gas ambient for MEMS encapsulation

Takagi

Kurashima

2017

Jpn. J. Appl. Phys.

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“…The most recent advanced tactile technologies discussed in the literature demonstrate the use of silicon-based or micro-electromechanical (MEMs) sensors which are not suitable for high-force, high abrasion, harsh environment applications [8]. While some work with macro-capacitive diaphragms has shown potential in meeting current needs, the low signal output from these sensors is difficult to quantify with onboard electronics, and the sensors are lacking the thorough design needed for identifying and quantifying the source of errors in the response [9]. In order to meet the demands of embedded, harsh environment applications, a number of environmental, mechanical, electrical, and volumetric restraints must be considered.…”

Section: Introductionmentioning

confidence: 99%

Ceramic–polymer capacitive sensors for tactile/force awareness in harsh environment robotic applications

Weadon

Evans

Sabolsky

2013

Smart Mater. Struct.

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The need for force feedback and spatial awareness of contact in harsh environment applications, such as space servicing, has been unsatisfied due to the inability of current sensor technology to resist environmental effects. In this work, capacitive sensors based on a thick film 0:3 connectivity ceramic:polymer composite structure were evaluated for potential use in future operations within robotic end effectors, withstanding temperatures ranging from −80 • C to 120 • C and forces up to 350 kPa. A thick film design is utilized to allow for ease of embedding, allowing sensors to be implemented into exciting robotic hardware with minimal intrusion, and protecting sensors from electron bombardment, radiation, and point concentrations from metal-on-metal contact. Taguchi design of experiments allows composition variables including sensor thickness, ceramic composition, ceramic particle size, ceramic volume loading, polymer character, modifier character, and the polymer:modifier ratio to be evaluated simultaneously. Dynamic thermal and mechanical loading techniques were implemented to characterize the composite sensors with in situ electrical acquisition. Individual composition variables were linked to the sensor magnitude, sensitivity, drift, and hysteresis, showing that the sensor response is optimized with a thickness of single microns, 10 vol% loading of nano-particle ceramics, and high molecular weight polymers with a low content of simple architecture modifiers lacking glass or melting temperatures in the working range.

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“…The sensor chip comprises a diaphragm and cavity part connected by direct bonding; the entire sensor chip is made from an SC sapphire. Ishihara and co-workers have reported the development of packaging technologies for an entirely sapphire-based capacitive pressure sensor chip, which is capable of withstanding a self-heating temperature of 200 °C that covers a dynamic absolute pressure range of 0–133 Pa, 0–1333 Pa, or 0–13 kPa. By adopting interlayer-less bonding methods, the packaging technology features low mechanical stress from the exterior metal body to the sensor chip and high corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

“…Several research findings on sapphire metallization process have been reported. − In some studies on diffusion bonding, − the results were used to develop a product for application in sensors . As regards the economical aspect of joining sapphire, the direct brazing technique using an active filler metal has been found to be a better choice compared to metallization and diffusion bonding; the latter processes are not only complex but also require very large machines and spaces, thereby resulting in a very high cost of fabrication of sensor components.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

Zaharinie

Huda

Ibrahim

et al. 2022

ACS Appl. Electron. Mater.

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The present research paper introduces a reliable and economical method for direct brazing using an active Ag−Cu−Ti filler metal that can ensure effective brazing. The sapphire−sapphire brazing process has been conducted at temperatures in the range of 830−900 °C for durations in the range of 15−30 min in a high-vacuum (10 −4 Pa) furnace. Material and microstructural characterization involved the use of scanning electron microscope-energy-dispersive system (SEM-EDS) and transmission electron microscope (TEM) for investigating the bonding joint morphologies. Two uniform reaction layers were observed to have formed at the sapphire/brazed area interface. On the sapphire side, the first reaction layer, which was uniform and had a thickness in the range of 0.13−0.17 μm, was identified as a TiO phase, whereas the second layer was identified as a Cu 3 Ti 3 O phase with a thickness in the range of 1.72−2.43 μm. The uniformity of the Cu 3 Ti 3 O phase was found to decrease with increasing brazing temperature and time. Therefore, in this research, a lower brazing temperature and time (830 °C/15 min) were chosen so as to avoid bonding degradation.

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Sapphire-based capacitance diaphragm gauge for high temperature applications

Cited by 10 publications

References 2 publications

Surface activated room-temperature bonding in Ar gas ambient for MEMS encapsulation

Surface activated room-temperature bonding in Ar gas ambient for MEMS encapsulation

Ceramic–polymer capacitive sensors for tactile/force awareness in harsh environment robotic applications

Analysis of the Reaction Layer Formed during Sapphire–Sapphire Brazing Using a Ag–Cu–Ti Filler Metal for Gas-Pressure Sensors

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