An Improved Performance Poly-Si Pirani Vacuum Gauge Using Heat-Distributing Structural Supports

Mitchell, J.; Lahiji, G.R.; Najafi, K.

doi:10.1109/jmems.2007.912711

Cited by 72 publications

(44 citation statements)

References 21 publications

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“…Most reported micro Pirani gauges are Si micromachined [8], which is costly, and their heaters may collapse during release or operation. The authors instead use a Pt wire bonded onto the pads on LTCC surface (Fig.13), as a low cost, sensitive and reliable micro Pirani gauge.…”

Section: Micro Pirani Gaugementioning

confidence: 99%

Investigation of a unified LTCC-based micromachining and packaging platform for high density/multifunctional microsystem integration

Miao

Jin

Gan

et al. 2012

2012 IEEE 62nd Electronic Components and Technology Conference

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3D system-in-package has recently been considered a major enabler for high density and heterogeneous microsystem integration. We hereby proposed the concept of a unified micromachining and packaging platform based on LTCC (low temperature cofired ceramic) material system and process, which is implemented by first enhancing an existing LTCC hybrid IC fabrication line and then integrating different LTCC micromachining process modules one by one. Hence, the unified process flow can be accomplished within just one single package-test house. The platform has been capable of micromachining basic 3D MEMS (micro electromechanical system) microstructures into LTCC laminates and using them as a packaging substrate for mounting IC/MEMS from other process platforms, realizing self-contained and versatile microsystems of high density. The 3D microstructures formation process consisting of green tape machining, lamination and cofiring are demonstrated. The designing, analysis and fabricated samples of various micro functional structure enabled by the platform are illustrated, including embedded cooling microchannels (capable of lowering substrate temperature by more than 50K), microaccelerometer for harsh environment, micro Pirani gauge for in-situ vacuum level monitoring and THz (tera hertz) vacuum microelectronic devices. Samples of overall packaged MEMS and IC chips with micromachined LTCC substrate are displayed, showing ultra-low leakage ( < 5×10 -11 Pa·m 3 /s) vacuum packaging capability and significantly enhanced device performance. In addition, the platform has demonstrated the potential of stacking several laminates with mounted chips into a 3D frame-like microsystem. In comparison, 3D integration purely based on Si micromachining, e.g. anodic-bonding based insitu wafer encapsulation, may only support a very limited spectrum of devices/materials and integration density and is somehow too expensive for many MEMS researchers. I IntroductionThree dimensional (3D) system-in-package (SIP) has recently been well accepted a major enabler for high density and heterogeneous microsystem integration [1-2]. Lately, various efforts for such a hybrid integration can be approximately categorized as following: a) hybrid of micromachining of different natures [2], b) micromachining micro mechanical structures over packaging or semiconductor substrate [3], c) micromachining of material traditionally for electronic packaging, like LTCC[4] and d) the diverse methodology of 3D stacking of various device planes and corresponding interconnect [5,6].We hereby propose the concept of a unified packaging and micromachining platform based on LTCC (low temperature cofired ceramic) material system and process. This platform is intended for facilitating a three dimensional, high density, agile and inexpensive integration and packaging of microstructures and ICs from various process lines. The authors modify an existing LTCC hybrid IC fabrication and packaging line into one capable of both packaging and 3D micromachining. With the LTCC micromachinin...

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Section: Micro Pirani Gaugementioning

confidence: 99%

Investigation of a unified LTCC-based micromachining and packaging platform for high density/multifunctional microsystem integration

Miao

Jin

Gan

et al. 2012

2012 IEEE 62nd Electronic Components and Technology Conference

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“…Longterm stability and in situ pressure measurement of traditional platform packages are often evaluated using helium leak-rate tests and Q-factor measurements from resonators integrated in the packages [8]. However, leak-test-based techniques require expensive equipment, and they cannot monitor small changes inside wafer-level micropackages because they are generally limited to a leak measurement resolution of 10 −10 Pa l/s [6]. Compared with resonators, Pirani gauges are easier to calibrate and test and usually have higher pressure sensitivities [7].…”

Section: Introductionmentioning

confidence: 99%

A Tube-Shaped Buried Pirani Gauge for Low Detection Limit With Small Footprint

Santagata

Creemer

Iervolino³

et al. 2011

J. Microelectromech. Syst.

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We present a micromachined Pirani gauge that combines low detection limit and strongly reduced footprint. It consists of a tube-shaped resistor that is buried in the silicon substrate. The choice of the tube geometry gives the resistor a very high structural rigidity. This enables the fabrication of much longer resistors, thus shifting the detection limit toward lower pressures. In addition, since the resistor is buried under the silicon surface, its footprint is kept very small. The high stiffness allowed the fabrication of a 3-mm-long and 1.8-μm-thick poly-Si tube with a 1-μm gap without buckling and/or stiction problems. It shows a detection limit of 0.1 Pa for a noise level of 50 μV, and it has a footprint of only 0.012 mm 2 . This is an improvement of at least 20 times compared with Pirani gauges with the same detection limit. Pirani tubes of 1.6-and 0.4-mm lengths have also been designed, fabricated, and tested. The 0.4-mm-long tube shows a low pressure limit of 2 Pa, whereas the tube of 1.6 mm shows a low pressure limit of 0.2 Pa. The measured transfer functions correspond very well to the 1-D analytical model.[ 2010-0281]Index Terms-Pirani gauge, pressure sensor, vacuum measurement.

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“…However, the stress of the membrane must be considered to achieve narrower air gap for increasing dynamic range [6]. The second group is microbridge used as the heater and the substrate as heat sink [8][9][10]. It is easy to fabricate and compatible with many MEMS devices fabrication.…”

Section: Introductionmentioning

confidence: 99%

A single crystal silicon micro-Pirani vacuum gauge with high aspect ratio structure

Jiang

Wang

Zhang

2010

Sensors and Actuators A: Physical

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An Improved Performance Poly-Si Pirani Vacuum Gauge Using Heat-Distributing Structural Supports

Cited by 72 publications

References 21 publications

Investigation of a unified LTCC-based micromachining and packaging platform for high density/multifunctional microsystem integration

Investigation of a unified LTCC-based micromachining and packaging platform for high density/multifunctional microsystem integration

A Tube-Shaped Buried Pirani Gauge for Low Detection Limit With Small Footprint

A single crystal silicon micro-Pirani vacuum gauge with high aspect ratio structure

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