4M Knowledge base - papers
A New Approach to Qualitiy Assurance in Resistance Welding for Microsensors Packaging
D. Ulieru(a), Alina Matei(b), Elena Ulieru(c), A. Tantau(c)
a: ROMES S.A., 126A, Iancu Nicolae Str., Bucharest, 72996, Romania
b: National Institute for Research and Development in Microtechnologies, 32B, Erou Iancu Nicolae Str., Bucharest, 077190, Romania
c: SITEX 45 SRL, 114, Ghica Tei Blvd., bl. 40, ap. 2, Dept. 2, Bucharest 72235, Romania
Abstract
The permanent development of microelectronics technologies provide new challenges for miniaturization and complexity increasing for new packaging technologies. So the exciting applications for microsystems, sensors and actuators production are looking for the best quality hermetic sealing of metal packages. The paper showed our researches and experiments results for a new approach to quality assurance in resistance welding. These will analyze the main causes of weld failures and also our methods of determining its value. On the basis of this requirement have monitored through the weld sequence, integrated concept of power monitor. The technical features developed a modern concept applicable to a wider range of fields. Our monitor could be used to wide range of welding technologies like distributed spot and focused spot, projection, roller spot and mash welding machines, working with single or three phase, ac. or dc. The experiments with our equipment have proven its advantage for fast production assembly line.
| 209 readsA New Concept for an Absolutely Encoded Angular Resolver
V. Mayer, T. Botzelmann, K.-P. Fritz, J. Seybold, H. Kück
Hahn-Schickard-Gesellschaft, Institute of Micro Assembly Technology, Allmandring 9b, 70569 Stuttgart, Germany
Abstract
At HSG-IMAT a new concept for an absolutely encoded optical angular resolver has been developed. The key element of the sensor concept is a disc with a high precision solid measure which is fabricated using the well known manufacturing process for compact discs (CD-Technology). Using this process, it is possible to fabricate a high precision solid measure in high quantities and at low manufacturing costs. To detect the absolute angular position, a laser beam is focused onto the solid measure. The beam is deflected by the diffractive gratings of the solid measure, whereupon the different first orders fall onto separated elements of a photo diode array. To verify the principle of operation an experimental setup assembled under a microscope, with a CCD-chip instead of a photodiode array, was used to demonstrate the signal modulation. Based on these experiments, a small size demonstrator device was designed and assembled. The successful experimental results with this demonstrator device show the large potential of this new sensor concept for different applications.
Bimaterial Actuators and Sensor with Built-in Compensation of the Ambient Temperature Interference
J. Matović(a), Z. Jakšić(b)
a: ISAS, Technical University, 1040, Vienna, Austria
b: IHTM, University of Belgrade, 11000, Belgrade, Serbia
Abstract
We present a novel simple and efficient method for the full removal of the influence of ambient temperature variations to the operation of bimaterial-based MEMS actuators and sensors. The removal of the undesired interference is achieved through the very structure of the bimaterial cantilever, by reversing the order of bimaterial constituent materials at a certain length. Thus an extremely simple geometry is obtained for full self-compensation of the structures. We performed the full simulation of our devices by the finite element method. The structures require standard surface micromachining and utilize only Si-technology compatible materials like polyimides or SU-8. A simple rule for the determination of the zero-deflection condition is presented. The described compensation method enables a significantly reduced bimaterial device area and a much higher packaging density in element arrays, as well as an improved signal-to-noise ratio. The method is especially convenient for photodetector arrays for direct conversion of infrared radiation spatial distribution into a visible image.
Mixed technologies for gas sensors microfabrication
Carmen Moldovan (a), Sebastian Sosin (a), Oana Nedelcu (a), Ulrike Kaufmann (b), Hans-Joachim Ritzhaupt-Kleissl (b),
Stefan Dimov (c), Petko Petkov (c), Robert Dorey (d), Katrin Persson (e), David Gomez (f), Per Johander(g)
a National Institute for R&D in Microtechnologies, Erou Iancu Nicolae 32 B, Bucharest 077190, Romania
b Forschungszentrum Karlsruhe, Institut für Materialforschung III, P.O. Box 3640, 76021 Karlsruhe, Germany ;
c Manufacturing Engineering and Multidisciplinary Technology Centre, Cardiff University;
d Nanotechnology Group, Cranfield University, Cranfield, Bedfordshire, UK;
e IMEGO, Arvid Hedvalls Backe 4, SE 411 33 Goteborg, Sweden;
f Fundacion Tekniker
g IVF - Industrial Research and Development Corporation; Argongatan 30, S431 53 Molndal, Sweden
Abstract
The paper presents the development of a novel suspended membrane resistive gas sensor on a ceramic substrate. The sensor is designed and simulated to be fabricated by combining laser milling techniques, conductive ceramic technology, thin film technology, and semiconductor metal oxides. Trenches are created in the alumina substrate in order to define the geometry of the heater using laser processing of the substrate. The heater is completed by filling the trenches with conductive ceramic paste and then baking to remove the solvent from the paste. The next step consists of polishing the surface to obtain a surface roughness small enough for thin film technology. A dielectric (SiO2 or ceramic) material is then deposited, acting as hot plate and also as electrical isolation between the heater and sensing electrode. The sensing electrode consists of an interdigitated resistor made of Au or Pt with thickness in the range of 2000 -3000 Å. The gas sensitive layer (SnO2) is deposited by screen printing or spinning. When heated it react with gas molecules and changes its resistivity, thereby acting as a sensor. The final step involves releasing the sensor, enabling it to be suspended on four bridges, to minimise the dissipation of the heat in the substrate.
categories
chemoresistive gas sensor | gas | Micro-sensors & actuators | mixed technologies | sensorsPhotosensor of CDSSE for Fiber Optics Applications
Peter Shindov(a), Nasko Elektronov(b),Valery Serbezov(c), Franz Herbst(c)
a: Technical College-"John Atanasoff"
b: JN-Corp.
c: Multicoats Ltd.
Abstract
The development of new generations of laser source for fiber optic’s applications require more fast new photosensors with spectral characteristics in visible range. The idea of this work is development of technology and device – fast photosensor with spectral range adapted to modern lasers for the quickly increasing needs of optoelectronics and fiber optics communications. By pulsed laser deposition (PLD) usage UV N2 Laser for ablation λ=337.1 nm, energy per pulse 8 mJ and CW 60 W CO2 Laser for heating are produced thin CdSxSe1-x films on quartz substrate. Polycrystalline thin films with thickness from 0.5 to 2.0 μm and dominant orientation – (002) are formed by energy density 4.5 J/cm2 and repetition rate 20 Hz .The thin films are investigated by EDAX and SEM. The films are additional thermo treatment for increasing ratio photocurrent – dark current. This ratio reaches 107. By means of TEA UV N2 Laser with energy per pulse-0.3 mJ, pulse duration 2 ns are formed planar Ohm contacts from CdO directly onto thin film. The contacts are investigated by XRD. By means of coordinate table the contacts are formed on the backside of the structure. The dimension of photosensitive structure is 250x250 μm. The distance between contacts areas is 10 μm. The spectral response of devices is measured. The maximum spectral sensitive is at λ=575 nm. Lux ampere characteristics are measured. The increasable fronts and decreаsаble fronts at the structure are measured. They are 2 ns, at ratio 1000.
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