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Junbo Wang - One of the best experts on this subject based on the ideXlab platform.

  • wireless passive intracranial pressure sensor based on Vacuum Packaging
    IEEE Sensors Journal, 2020
    Co-Authors: Ming Zhao, Qiuxu Wei, Jia Che, Deyong Che, Junbo Wang
    Abstract:

    This paper presents a wireless passive pressure sensor based on a pressure-sensitive capacitor specifically designed to monitor intracranial pressure (ICP) in patients with traumatic brain injuries. It is crucial that temperature will affect the accuracy of pressure detection. To improve temperature stability, the capacitor is composed of an SOI wafer as the sensing element and a glass cap for Vacuum Packaging. To realize reliable Vacuum Packaging, it is vital to transfer the electrical signal out of the Vacuum cavity. The experimental results show that the proposed sensor demonstrated averaged pressure sensitivity and averaged temperature sensitivity of 0.5803 Hz/kPa and 0.024 Hz/°C. Additionally, the in-vivo test in the animal show that the proposed sensor has the similar detection effect with the commercial wired sensor, and naturally has the advantage of reducing the risk of infection, which further validated the feasibility and effectiveness of the wireless passive ICP monitoring system.

  • a temperature insensitive resonant pressure micro sensor based on silicon on glass Vacuum Packaging
    Sensors, 2019
    Co-Authors: Chao Xiang, Junbo Wang, Deyong Che, Jia Che
    Abstract:

    This paper presents a temperature-insensitive resonant pressure sensor, which is mainly composed of a silicon-on-insulator (SOI) wafer for pressure measurements and a silicon-on-glass (SOG) cap for Vacuum Packaging. The variations of pressure under measurement bend the pressure sensitive diaphragm and regulate the intrinsic frequencies of the resonators in the device layer. While, variations of temperature cannot significantly change the intrinsic frequencies of the resonators, due to the SOG cap to offset generated thermal stress. Numerical simulations, based on finite element analysis, were conducted to calculate the residual thermal stress and optimize the sensing structures. Experimental results show that the Q-factors of the resonators are higher than 16,000, with a differential pressure sensitivity of 11.89 Hz/kPa, a nonlinearity of 0.01% F.S and a low fitting error of 0.01% F.S with the pressure varying from 100 kPa to 1000 kPa. In particular, a temperature sensitivity of ~1 Hz/°C was obtained in the range of -45 °C to 65 °C, which is one order of magnitude lower than the previously reported counterparts.

  • au maskless patterning for Vacuum Packaging using the electrochemical method
    Nanotechnology and Precision Engineering, 2018
    Co-Authors: O Xie, Jia Che, Deyong Che, Junbo Wang, We Hong
    Abstract:

    Abstract The interconnection of wires is an important issue in Vacuum-packaged microelectromechanical systems devices because of the difficulties of hermetical sealing and electrical insulation. This paper presents an approach of Au film selective patterning on highly uneven surfaces for wire interconnections of devices in which silicon-on-insulator (SOI) wafers are anodically bonded to glass. The Au film on the handle layer, functioned as an anode, was selectively removed with electrochemical dissolution in a chloride solution. The choice of etchant solution and etching conditions were optimized to improve the process efficiency, resulting in a high yield of gold portions within the via holes for wire interconnection. The proposed wire interconnection technology was employed to fabricate a Vacuum-packaged resonant pressure sensor as a proof-of-concept demonstration. Reliable wire bonding and Vacuum package were achieved as well as a Q factor that does not decrease over a year. As a platform technology, this method provides a new approach of wire interconnection for Vacuum-packaged devices based on SOI–glass anodic bonding.

  • a lateral differential resonant pressure microsensor based on soi glass wafer level Vacuum Packaging
    Sensors, 2015
    Co-Authors: O Xie, Jia Che, Deyong Che, Yonghao Xing, Yanshuang Wang, Junbo Wang
    Abstract:

    This paper presents the fabrication and characterization of a resonant pressure microsensor based on SOI-glass wafer-level Vacuum Packaging. The SOI-based pressure microsensor consists of a pressure-sensitive diaphragm at the handle layer and two lateral resonators (electrostatic excitation and capacitive detection) on the device layer as a differential setup. The resonators were Vacuum packaged with a glass cap using anodic bonding and the wire interconnection was realized using a mask-free electrochemical etching approach by selectively patterning an Au film on highly topographic surfaces. The fabricated resonant pressure microsensor with dual resonators was characterized in a systematic manner, producing a quality factor higher than 10,000 (~6 months), a sensitivity of about 166 Hz/kPa and a reduced nonlinear error of 0.033% F.S. Based on the differential output, the sensitivity was increased to two times and the temperature-caused frequency drift was decreased to 25%.

  • A High-Q Resonant Pressure Microsensor with Through-Glass Electrical Interconnections Based on Wafer-Level MEMS Vacuum Packaging
    Sensors, 2014
    Co-Authors: Zhenyu Luo, Junbo Wang, Deyong Chen, Yinan Li, Jian Chen
    Abstract:

    This paper presents a high-Q resonant pressure microsensor with through-glass electrical interconnections based on wafer-level MEMS Vacuum Packaging. An approach to maintaining high-Vacuum conditions by integrating the MEMS fabrication process with getter material preparation is presented in this paper. In this device, the pressure under measurement causes a deflection of a pressure-sensitive silicon square diaphragm, which is further translated to stress build up in “H” type doubly-clamped micro resonant beams, leading to a resonance frequency shift. The device geometries were optimized using FEM simulation and a 4-inch SOI wafer was used for device fabrication, which required only three photolithographic steps. In the device fabrication, a non-evaporable metal thin film as the getter material was sputtered on a Pyrex 7740 glass wafer, which was then anodically bonded to the patterned SOI wafer for Vacuum Packaging. Through-glass via holes predefined in the glass wafer functioned as the electrical interconnections between the patterned SOI wafer and the surrounding electrical components. Experimental results recorded that the Q-factor of the resonant beam was beyond 22,000, with a differential sensitivity of 89.86 Hz/kPa, a device resolution of 10 Pa and a nonlinearity of 0.02% F.S with the pressure varying from 50 kPa to 100 kPa. In addition, the temperature drift coefficient was less than −0.01% F.S/°C in the range of −40 °C to 70 °C, the long-term stability error was quantified as 0.01% F.S over a 5-month period and the accuracy of the microsensor was better than 0.01% F.S.

Thomas R Schime - One of the best experts on this subject based on the ideXlab platform.

  • low cost wafer level Vacuum Packaging for mems
    Mrs Bulletin, 2003
    Co-Authors: Roland W Gooch, Thomas R Schime
    Abstract:

    Vacuum Packaging of high-performance surface-micromachined uncooled microbolometer detectors and focal-plane arrays (FPAs) for infrared imaging and nonimaging applications, inertial MEMS (microelectromechanical systems) accelerometers and gyroscopes, and rf MEMS resonators is a key issue in the technology development path to low-cost, high-volume MEMS production. In this article, two approaches to Vacuum Packaging for MEMS will be discussed. The first is component-level Vacuum Packaging, a die-level approach that involves Packaging individual die in a ceramic package using either a silicon or germanium lid. The second approach is wafer-level Vacuum Packaging, in which the Vacuum-Packaging process is carried out at the wafer level prior to dicing the wafer into individual die. We focus the discussion of MEMS Vacuum Packaging on surface-micromachined uncooled amorphous silicon infrared microbolometer detectors and FPAs for which both component-level and wafer-level Vacuum Packaging have found widespread application and system insertion. We first discuss the requirement for Vacuum Packaging of uncooled a-Si microbolometers and FPAs. Second, we discuss the details of the component-level and wafer-level Vacuum-Packaging approaches. Finally, we discuss the system insertion of wafer-level Vacuum Packaging into the Raytheon 2000AS uncooled infrared imaging camera product line that employs a wafer-level-packaged 160 × 120 pixel a-Si infrared FPA.

  • wafer level Vacuum Packaging for mems
    Journal of Vacuum Science and Technology, 1999
    Co-Authors: R Gooch, Thomas R Schime, W Mccardel, D Gilmou, W Koziarz
    Abstract:

    Vacuum Packaging of high performance infrared (IR) MEMS uncooled detectors and arrays, inertial MEMS accelerometers and gyros, and radio frequency (rf) MEMS resonators is a key issue in the technology development path to low cost, high volume MEMS production. Wafer-level Vacuum Packaging transfers the Packaging operation into the wafer fab. It is a product neutral enabling technology for commercialization of MEMS for home, industry, automotive, and environmental monitoring applications. 4 in. wafer-level Vacuum Packaging has been demonstrated using IR MEMS bolometers and results will be presented in this article. In addition to the wafer-level Packaging results, Vacuum package reliability results obtained on component-level ceramic Vacuum packages will also be presented.

K Najafi - One of the best experts on this subject based on the ideXlab platform.

  • gold indium transient liquid phase tlp wafer bonding for mems Vacuum Packaging
    International Conference on Micro Electro Mechanical Systems, 2008
    Co-Authors: W C Welch, K Najafi
    Abstract:

    This paper reports the first wafer-level Vacuum packages created with gold-indium transient liquid phase (TLP) wafer bonding. The packages were bonded at 200degC for 1 hour under a Vacuum environment in a commercially available wafer bonder. After bonding, the integrated getters were activated for 1 hour resulting in internal pressures as low as 200 mTorr. The pressures have been stable for over 6 months as measured by integrated Pirani gauges. Although no leak rate trend has been observed, the worst case leak rate that fits within the error of the pressure measurement is 16 mTorr/year (1ldr10-16 atm.cc.s-1).

  • nickel tin transient liquid phase tlp wafer bonding for mems Vacuum Packaging
    TRANSDUCERS 2007 - 2007 International Solid-State Sensors Actuators and Microsystems Conference, 2007
    Co-Authors: W C Welch, K Najafi
    Abstract:

    This paper reports Vacuum data for nickel-tin transient liquid phase (TLP) wafer bonding. Two wafers, one with a titanium getter and another with Pirani Vacuum sensors, were bonded for 1.5 hours at 300 °C. Initial pressures were as low as 200 mTorr and have remained stable for half a month. After several days, some of the packages were heated to 400 °C for 10 minutes to test the thermal integrity of the TLP bond. The bond remained intact; the pressure inside each of the cavities dropped by further activating the getter and has remained steady at the new lower pressure for several weeks.

  • Vacuum Packaging technology using localized aluminum silicon to glass bonding
    IEEE\ ASME Journal of Microelectromechanical Systems, 2002
    Co-Authors: Yu-ting Cheng, K Najafi, C.t. Nguyen
    Abstract:

    A glass Vacuum package based on localized aluminum/silicon-to-glass bonding has been successfully demonstrated. A constant heat flux model shows that heating can be confined locally in the dielectric layer underneath a microheater as long as the width of the microheater and the thickness of silicon substrate are much smaller than the die size and a good heat sink is placed underneath the silicon substrate. With 3.4 W heating power, /spl sim/0.2 MPa applied contact pressure and 90 min wait time before bonding, Vacuum encapsulation at 25 mtorr (/spl sim/3.33 Pa) can be achieved. Folded-beam comb drive /spl mu/-resonators are encapsulated and used as pressure monitors. Long-term testing of Vacuum-packaged p-resonators with a Quality Factor (Q) of 2500 has demonstrated stable operation after 69 weeks. A /spl mu/-resonator with a Q factor of /spl sim/9600 has been Vacuum encapsulated and shown to be stable after 56 weeks.

  • Vacuum Packaging technology using localized aluminum silicon to glass bonding
    International Conference on Micro Electro Mechanical Systems, 2001
    Co-Authors: Yu-ting Cheng, C.t. Nguyen, K Najafi
    Abstract:

    A Vacuum package based on localized aluminum/silicon-to-glass bonding has been successfully demonstrated. With 3.4 watts heating power, /spl sim/0.2 MPa applied contact pressure, and 90 minutes wait time before bonding, Vacuum encapsulation at 25 mtorr can be achieved. Folded-beam comb drive /spl mu/-resonators are encapsulated and used as pressure monitors. Long-term testing of un-annealed Vacuum-packaged /spl mu/-resonators with a Q of 2500 has demonstrated stable operation after 20 weeks. A /spl mu/-resonator with Q of /spl sim/9600 has been Vacuum encapsulated and shown to be stable after 7 weeks.

Dorota S. Temple - One of the best experts on this subject based on the ideXlab platform.

  • Wafer-level Vacuum Packaging of smart sensors
    Sensors (Switzerland), 2016
    Co-Authors: Allan Hilton, Dorota S. Temple
    Abstract:

    The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors—“low cost” for ubiquitous presence, and “smart” for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for Packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level Vacuum Packaging technology of smart sensors. We describe the processes needed to create the wafer-scale Vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain Vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level Vacuum Packaging technology.

I N Savvaidis - One of the best experts on this subject based on the ideXlab platform.

  • combined effects of salting oregano oil and Vacuum Packaging on the shelf life of refrigerated trout fillets
    Food Microbiology, 2010
    Co-Authors: L Frangos, V Giatrakou, A Ntzimani, N Pyrgotou, I N Savvaidis
    Abstract:

    Abstract The present study evaluated the effect of salt, oregano essential oil (EO) and Packaging on fresh rainbow trout fillets during storage at 4 °C. Treatments included the following: A1 (control samples, unsalted: air packaged), A2 (salted: air packaged), VP1 (salted, Vacuum packaged), VP2 (salted, Vacuum packaged with added oregano EO 0.2% v/wt), and VP3 salted, Vacuum packaged with added oregano EO 0.4% v/wt). Lactic acid bacteria (LAB) (to a greater extent), followed by H 2 S-producing bacteria (including Shewanella putrefaciens ), Pseudomonas spp. and Enterobacteriaceae reached higher populations in A1, A2 (as compared to VP1, VP2 and VP3) trout samples. Treatments VP1, VP2 and VP3 produced significantly lower ( P

  • combined natural antimicrobial treatments edta lysozyme rosemary and oregano oil on semi cooked coated chicken meat stored in Vacuum packages at 4 c microbiological and sensory evaluation
    Innovative Food Science and Emerging Technologies, 2010
    Co-Authors: A Ntzimani, V Giatrakou, I N Savvaidis
    Abstract:

    Abstract The present study examined the effect of natural antimicrobials: Ethylenediaminetetraacetate (EDTA), lysozyme, rosemary and oregano oil and their combinations, on the shelf-life of semi cooked coated chicken fillets stored under Vacuum Packaging (VP), at 4 ± 0.5 °C for a period of 18 days. The treatments of semi cooked coated chicken fillets examined in the present study were the following: Air-packaged (A, control samples), Vacuum-packaged (VP), VP with EDTA–lysozyme solution 1.50% w/w, (VP + EL), VP with rosemary oil 0.20% v/w, (VP + R), VP with oregano oil 0.20% v/w, (VP + O), VP with EDTA–lysozyme solution and rosemary oil (VP + EL + R) and finally VP with EDTA–lysozyme and oregano oil (VP + EL + O). The shelf-life of the samples was determined using both microbiological and sensory analyses. Among the antimicrobial combinations examined in the present study, the treatments VP + EL + R and VP + EL + O were the most effective against the growth of Gram-negative, Gram-positive bacteria, and to a lesser extent on yeasts. Based on both microbiological (TVC data) and sensory (taste attribute) analyses, treatments: VP and VP + O gave a shelf life extension of 6 days, whereas treatments VP + EL + R and VP + EL + O produced a shelf-life extension of 7–8 days, as compared to the control samples. Industrial Relevance The present research has highlighted the use of natural antimicrobial treatment combinations, including: EDTA, lysozyme, rosemary and oregano oil and their combinations, in the extension of shelf-life of semi cooked coated chicken fillets stored under Vacuum Packaging at 4 °C for a period of 18 days. Establishing, the determination of the shelf-life of fresh poultry and products represents a challenge for food companies as poultry meat has a short shelf-life, which causes substantial practical problems for its distribution. Therefore, knowledge of natural preservatives, that can be used as alternatives to chemical additives, that could extend the products' shelf life can have an important economic feedback by reducing losses attributed to spoilage and by allowing the products to reach distant and new markets. This study has shown that combinations of natural antimicrobials can extend the shelf-life of the product.

  • combined effect of Vacuum Packaging and oregano essential oil on the shelf life of mediterranean octopus octopus vulgaris from the aegean sea stored at 4 c
    Food Microbiology, 2009
    Co-Authors: I Atrea, A Papavergou, I Amvrosiadis, I N Savvaidis
    Abstract:

    The present study evaluated the use of Vacuum Packaging (alone) or with addition of oregano essential oil (EO), as an antimicrobial treatment for shelf-life extension of fresh Mediterranean octopus stored under refrigeration for a period of 23 days. Four different treatments were tested: A, control sample; under aerobic storage in the absence of oregano essential oil; VP, under Vacuum Packaging in the absence of oregano essential oil; and VO1, VO2, treated samples with oregano essential oil 0.2 and 0.4% (v/w), respectively, under VP. Of all the microorganisms enumerated, Pseudomonas spp., H2S-producing bacteria and lactic acid bacteria (LAB) were the groups that prevailed in octopus samples, irrespective of antimicrobial treatment. With regard to the chemical freshness indices determined, thiobarbituric acid (TBA) values were low in all octopus samples, as could have been expected from the low fat content of the product. Both trimethylamine nitrogen (TMA-N) and total volatile basic nitrogen (TVB-N) values of oregano treated under VP octopus samples were significantly lower compared to control samples during the entire refrigerated storage period. Based primarily on sensory evaluation (odor), the use of VP, VO1 and VO2 extended the shelf-life of fresh Mediterranean octopus by ca. 3, 11 and 20 days, respectively.