Encapsulation of vacuum sensors in a waffr level package using a gold-silicon eutectic

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

doi:10.1109/sensor.2005.1496570

Cited by 39 publications

(28 citation statements)

References 8 publications

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“…The breakthrough was determined by the least-loaded microchannel and not by the total amount of adsorbent mass in the device, hence it could not be easily used for quantitative analysis without characterizing the amount of effective adsorbent material. 76 76…”

Section: Initial Experimentsmentioning

confidence: 99%

Sample extraction and injection with a microscale preconcentrator.

Robinson

Chan²

2007

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This report details the development of a microfabricated preconcentrator that functions as a fully integrated chemical extractor-injector for a microscale gas chromatograph (GC). The device enables parts-per-billion detection and quantitative analysis of volatile organic compounds (VOCs) in indoor air with size and power advantages over macro-scale systems. The 44 mm 3 preconcentrator extracts VOCs using highly adsorptive, granular forms of graphitized carbon black and carbon molecular sieves. The micron-sized silicon cavities have integrated heating and temperature sensing allowing low power, yet rapid heating to thermally desorb the collected VOCs (GC injection). The keys to device construction are a new adsorbent-solvent filling technique and solvent-tolerant wafer-level silicon-gold eutectic bonding technology. The product is the first granular adsorbent preconcentrator integrated at the wafer level. Other advantages include exhaustive VOC extraction and injection peak widths an order of magnitude narrower than predecessor prototypes. A mass transfer model, the first for any microscale preconcentrator, is developed to describe both adsorption and desorption behaviors. The physically intuitive model uses implicit and explicit finite differences to numerically solve the required partial differential equations. The model is applied to the adsorption and desorption of decane at various concentrations to extract Langmuir adsorption isotherm parameters from effluent curve measurements where properties are unknown a priori.

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Section: Initial Experimentsmentioning

confidence: 99%

Sample extraction and injection with a microscale preconcentrator.

Robinson

Chan²

2007

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“…First interactions between Al and Si were already observed slightly above 300 °C. Furthermore Middlehoek, Najafi, Mitchell, Lani, and Wiemer publicized the results of their investigations regarding eutectic compositions, multi layers of Au and Si, yield and reliability as well as the realization of hermetic packages from 1995 to 2005 [5][6][7][8][9].…”

Section: Introduction -State Of the Artmentioning

confidence: 99%

Eutectic wafer bonding for 3-D integration

Baum

Jia

Haubold

et al. 2010

3rd Electronics System Integration Technology Conference ESTC

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Successful commercialization of MEMS products extremely depends on cost factors. Especially the role of integration technologies like packaging at different levels, combining MEMS with integrated circuits, and to realize 3-dimensional packaged devices is more important than ever. Bonding technologies at wafer level are key factors for 3-d integration, realizing the mechanical bond and fulfilling certain requirements like strength, hermeticity, and reliability as well as the electrical interconnection of the different functional components. From a great variety of bonding techniques eutectic bonding has got a special importance today because both hermetically sealed packages and electrical interconnects could be performed within one bonding process. Furthermore, there are some advantages such as low processing temperature, low resulting stress, and high bonding strength. These properties are mainly investigated up today. Since the early 90-ies eutectic wafer bonding is known from very large scale integration (VLSI) and is used very often in industry. Even before that time eutectic bond processes were already used in the field of chip bonding.Within this paper the development and investigation of at least two eutectic bonding technologies will be described and characterized. Although the mechanical and micro structural properties of the bond will be shown, the realization and test of electrical interconnects is focused very clearly. With an integration of certain test structures the bonding strength, the electrical properties, and the hermeticity of eutectic bonds could be measured and evaluated. At least it will be concluded with an outlook for the feasibility of eutectic bonding in 3-d integrated smart micro systems.

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“…Raman spectroscopy as another optical technique also depends on a cap transparent to the light used to excite the Raman spectrum of the gas inside the cavity [12], [13]. Micro-Pirani vacuum sensors which are based on the measurement of the thermal conductance of the surrounding gas have also been realized for leak detection in a wafer-level package [14], [15]. The availability of the processing environment for such test structures may be a reason to disregard this principle.…”

Section: Introductionmentioning

confidence: 99%

Hermeticity of eutectic bond layers for sensor packages on wafer-level

Schneider

Rank

Müller-Fiedler

et al. 2010

3rd Electronics System Integration Technology Conference ESTC

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In MEMS industry there is a high demand for reliable hermetic wafer-level encapsulation. This paper presents a methodology to monitor the pressure inside a package after the wafer-level bonding process. Therefore, novel micro-electro-mechanical resonators designed as double ended tuning forks (DETFs) were built to measure the quality factor Q as a function of the inside cavity pressure. Obtained experimental results clearly verified the feasibility of the developed MEMS structures, providing a simple method to evaluate the hermeticity of wafer bonding technologies

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Encapsulation of vacuum sensors in a waffr level package using a gold-silicon eutectic

Cited by 39 publications

References 8 publications

Sample extraction and injection with a microscale preconcentrator.

Sample extraction and injection with a microscale preconcentrator.

Eutectic wafer bonding for 3-D integration

Hermeticity of eutectic bond layers for sensor packages on wafer-level

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