Energie-Umweltmanagement

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Wir bringen Energie & Umwelt zusammen

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    Publication
    Solar radiation as a building control parameter – A comparison of measured and predicted values
    (Konferenzbeitrag zur internationalen Konferenz "Indoor Climate of Buildings 2019", 2019)
    Plank Helmut
    ;
    Klanatsky Peter
    ;
    Veynandt François
    ;
    Stelzer Roman
    ;
    Traunmüller Wolfgang
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    Publication
    A new approach for evaluation of fatigue life of al wire bonds in power electronics
    (Elsevier, 2014-02-16)
    Czerny, Bernhard 
    ;
    Khatibi, Golta 
    ;
    Lederer, Martin 
    ;
    Kotas, Agnieszka Betzwar 
    ;
    Weiss, Brigitte 
    Ultrasonically bonded A1 wire bonds on A1 metallization pads are widely used in power semiconductors. The required long time reliability of the devices is highly dependent on the interfacial quality of A1 wire and the bond pad. Reliability of wire bonds is commonly assessed by thermal and power cycling tests. Accelerated mechanical fatigue testing can be used as an alternative to these time consuming procedures. In the present study, lifetime of thick A1 wedge bonds on Si substrates was investigated using a novel mechanical fatigue testing technique operating at high frequencies and elevated temperatures. The influence of microstructure, testing temperature and frequency on lifetime of A1 wire bonds was investigated. Finite element analysis was applied to calculate the stress distribution at the interfacial region and to establish life time prediction curves. The results of mechanical isothermal fatigue curves were compared and correlated with thermal cycling data of Al wire bonds. Copyright © 2014 by The Minerals, Metals & Materials Society.
      53Scopus© Citations 1
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    Publication
    Loop formation effects on the lifetime of wire bonds for power electronics
    (2020-03-24)
    Czerny, Bernhard 
    ;
    Ribbeck, Hans-Georg von 
    ;
    Doehler, Torsten 
    ;
    Khatibi, Golta 
    ;
    Geissler, Ute 
    In the present work, the influence of loop forming aspects on the reliability of US-bonded aluminium heavy wires was studied, combining three measurement techniques, for the first time: Laser confocal microscopy based wrinkling characterization, accelerated lifetime measurements BAMFIT and destructive pull tests. The focus of this study was the systematic investigation of the heel region of the wire bond depending on process parameters and especially on the loop geometry regarding durability and lifetime. As first results, effects reducing durability were identified which are not apparent in normal testing and a recommendation for the use of reverse movements can be given.
      63
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    Publication
    In situ vibration measurements on power modules under operating conditions
    (Elsevier, 2012-04-16)
    Czerny, Bernhard 
    ;
    Nagl, Bernhard 
    ;
    Lederer, Martin 
    ;
    Trnka, A. 
    ;
    Khatibi, Golta 
    ;
    Thoben, Markus 
    The subject of this investigation was determination of thermo-mechanically induced displacement of the components inside a power module under operation conditions. It is well known that lifetime of insulated gate bipolar transistor (IGBT) modules is limited by thermo-mechanical fatigue. Wire bonded interconnects inside the IGBTs count as critical sites where crack initiation and failure is observed. In this study the temperature dependent periodic deformation of wire-bonds under operating conditions was determined by using a laser Doppler vibrometer (LDV) and thermal imaging camera. Furthermore finite element analyses (FEA) were conducted to obtain the strain values needed for lifetime assessments.
      43Scopus© Citations 5
  • No Thumbnail Available
    Publication
    Accelerated mechanical fatigue interconnect testing method for electrical wire bonds
    (2018-04-25)
    Czerny, Bernhard 
    ;
    Khatibi, Golta 
    Every new development in device performance and packaging design, can drastically affect the reliability of devices due to implementation of new materials and design changes. High performance and high reliability demands in power electronics over several decades and a short time to market development, raise the need for very fast reliability testing methods. In this study a mechanical fatigue testing method is presented for evaluating the interfacial fatigue resistance of heavy Al wire bonded interconnects in high power modules. By separating the concurrent thermal, mechanical and environmental failure mechanisms a selective investigation of the desired failure mode is possible. The setup is designed to reproduce the thermo-mechanical shear stresses by mechanical means, while provoking the same lift-off failure mode as in power cycling tests. With a frequency variable test setup of a few Hz up to several kHz, measurements from 103 up to 108 loading cycles and determining the influence of the testing frequency on the fatigue life are possible. A semi-automated bond wire fatigue tester operating at 60 kHz is presented which is suitable for rapid screening and qualification of a variety of wire bonds at the stages of development and during the production. © 2018 Walter de Gruyter GmbH, Berlin/Boston.
      58Scopus© Citations 13
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    Publication
      75
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    Publication
    Innovative Hydrogen Storage in Hollow Glass-Microspheres
    (2009)
    Keding, Marcus 
    ;
    Schmid, G. 
    ;
    Tajmar, Martin 
      84
  • No Thumbnail Available
    Publication
    Klimakälteerzeugung aus Wärme
    (Technische Universität Graz, 2020-02-12)
    Krotil, Richard 
      115
  • No Thumbnail Available