Microelectromechanical system-based vacuum gauge for measuring pressure and outgassing rates in miniaturized vacuum microelectronic devices

Kuljic, Rade; Chang, J.; Jayapratha, Nithya; Dankovic, Tatjana; Banerjee, Koushik; Feinerman, Alan; Busta, H.H.

doi:10.1116/1.3562271

Cited by 16 publications

(7 citation statements)

References 13 publications

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“…A large number of micromachined Pirani gauges have been developed so far [4,11,15,16,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] using a variety of processes and geometries. With respect to their geometry, however, they can be divided into two groups.…”

Section: Introductionmentioning

confidence: 99%

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Santagata¹,

Creemer²,

Iervolino³

et al. 2012

J. Micromech. Microeng.

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Here the integration of a tube-shaped Pirani gauge with a SiN thin-film encapsulation process is presented. The tube geometry gives the sensor a very low detection limit with a small footprint, since the tube is buried under the silicon surface. The Pirani tube is very suitable for in situ evaluation of MEMS vacuum packaging. Moreover, since the Pirani gap is all around the tube and deep below the silicon surface, the deflection of the encapsulation shell is not a concern and wafer-level measurement of the device is possible. Pirani tubes with different lengths are encapsulated inside SiN micropackages in order to measure the resulting vacuum level achieved after the encapsulation step. The longest tube shows a detection limit of 0.1 Pa for a noise level of 50 μV and it has a footprint of only 0.006 mm 2 . The pressure inside the sealed micropackage was extracted to be 0.7 kPa. Furthermore, the pressure is monitored over time to evaluate the hermeticity of the packages. A leak rate of 8×10 −18 Pa m 3 s −1 was measured over four months time.

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Section: Introductionmentioning

confidence: 99%

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Santagata¹,

Creemer²,

Iervolino³

et al. 2012

J. Micromech. Microeng.

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“…The sensing element consisting of a meander shaped Ni resistor having thickness of 30nm is placed in the center of thermally insulating support of SiN having thickness of 1 μm. The pressure measurement range has been extended by increasing the thermal resistance of the H shaped device over a previously published membrane device [2,3] from 6x10 4 K/W to 3x10 5 K/W. Further improvement of an H shaped device was performed by fabricating a device with improved thermal resistance larger than 5x10 6 K/W and maintaining d=1200 μm.…”

Section: Discussionmentioning

confidence: 99%

Thermal-based MEMS vacuum gauges for measuring pressures from 10<sup>−2</sup> Torr to 10<sup>−6</sup> Torr

Zaker

Farid

Selvaraj

et al. 2012

25th International Vacuum Nanoelectronics Conference

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Bulk micromachined Pirani gauges were designed and fabricated using an H-shaped 1 µm thick silicon nitride support structure and 30 nm of Ni for the meander resistors and connecting metal lines. The distance d between the resistor element and the cold junction was chosen to be 1200 µm. From theoretical and experimental considerations, it is shown that pressures below 10 -4 Torr can be measured if the thermal resistances of the two metal lines which connect the resistor element to the cold junction and the thermal support structures are about or larger than 1x10 6 K/W. Also, the distance d between the resistor element and the cold junction needs to be near or larger than 1000 µm.

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“…Micromachined Pirani gauges have become a very useful tool for hermeticity monitoring for wafer-level packages [14,15]. Surface micromachined Pirani gauges are typically made of a thin metal resistive wire separated from the substrate by a sub-micron gap.…”

Section: Design and Fabrication Of Pirani Gauges Covered By Wafer-lev...mentioning

confidence: 99%

Thin-film encapsulation technology for above-IC MEMS wafer-level packaging

Zhang¹,

Cicek²,

Nabki³

et al. 2013

J. Micromech. Microeng.

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This work presents a low-cost and low-temperature wafer-level packaging solution for microelectromechanical systems (MEMS) devices. Heat-sensitive polymer poly(propylene carbonate) is used as the sacrificial material to release the capping layer in a clean and fast manner. Free-standing caps made of amorphous silicon carbide films and as large as 450 μm in diameter are successfully fabricated. To demonstrate the validity of this technology, surface-micromachined Pirani vacuum gauges are fabricated as an example of MEMS devices and encapsulated. Capped Pirani gauges respond to pressure between 1 mTorr and 1 atm. The Pirani gauges are sealed with Parylene C films that exhibit near-hermetic properties and the initial sealing pressure for 300 μm diameter cavities is characterized to be in the range of tens of torr.

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Microelectromechanical system-based vacuum gauge for measuring pressure and outgassing rates in miniaturized vacuum microelectronic devices

Cited by 16 publications

References 13 publications

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Thermal-based MEMS vacuum gauges for measuring pressures from 10<sup>−2</sup> Torr to 10<sup>−6</sup> Torr

Thin-film encapsulation technology for above-IC MEMS wafer-level packaging

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Microelectromechanical system-based vacuum gauge for measuring pressure and outgassing rates in miniaturized vacuum microelectronic devices

Cited by 16 publications

References 13 publications

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Tube-shaped Pirani gauge forin situhermeticity monitoring of SiN thin-film encapsulation

Thermal-based MEMS vacuum gauges for measuring pressures from 10<sup>&#x2212;2</sup> Torr to 10<sup>&#x2212;6</sup> Torr

Thin-film encapsulation technology for above-IC MEMS wafer-level packaging

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Thermal-based MEMS vacuum gauges for measuring pressures from 10<sup>−2</sup> Torr to 10<sup>−6</sup> Torr