Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM

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  • Publication
    Influence of backbone structure, conversion and phenolic co-curing of cyanate esters on side relaxations, fracture toughness, flammability properties and water uptake and toughening with low molecular weight polyethersulphones
    ( 2018)
    Uhlig, Christoph
    ;
    Bauer, Monika
    ;
    Bauer, Jörg
    ;
    Kahle, Olaf
    ;
    Taylor, Ambrose C.
    ;
    Kinloch, Anthony J.
    The effect of backbone structure and Conversion of polycyanurate networks on solid state properties has been studied and compared to co-curing with bisphenol-A. Dynamic mechanical behaviour, density, flammability properties, fracture toughness and long-term water uptake were investigated. The intensity of the g-relaxation increases, room temperature density decreases with increasing conversion, both due to increasing free volume with increasing conversion. A brittle-ductile transition was detected by precise fracture toughness measurements; above a critical conversion the fracture toughness rises suddenly from extremely low values to a plateau or maximum: Networks with higher toughness show a maximum, those with lower toughness a plateau. Bisphenol-A modification causes intrinsic toughness variations. Toughening of two different cyanate esters with polyethersulphones synthesized with various molecular weights between 3000 and 10,500 (Mn) was investigated. Significant toughening effects can be achieved already with intermediate molecular weights lower than those of commercially-available high-Tg amorphous thermoplastics. Long-term water uptake measurements at 28 °C, 50 °C and 70 °C over two years show a non-Fickian part of the water uptake for all cyanate esters even at temperatures as low as 28 °C. The effects of backbone structure, conversion and storage temperature are discussed in detail.
  • Publication
    Determination of the glass transition temperature in thin polymeric films used for microelectronic packaging by temperature-dependent spectroscopic ellipsometry
    ( 2017)
    Bittrich, E.
    ;
    Windrich, F.
    ;
    Martens, D.
    ;
    Bittrich, L.
    ;
    Häussler, L.
    ;
    Eichhorn, K.-J.
    We characterized the glass transition temperature Tg of thin polyimide films by temperature-dependent spectroscopic ellipsometry and compared the results to DSC measurements of the bulk polymer. The effect of the curing temperature on Tg and the thermal expansion a(T) was analyzed. An improved ellipsometric data evaluation was used to get most precise and reliable Tg data. Tg increased with increasing curing temperature, while the bulk Tg was considerably lower than the thin film Tg. Both observations are attributed to the temperature sensitive release of the imidization by-product 2-hydroxyethyl methacrylate (HEMA) and crosslinker components as well as decomposition products from the material. Variation in the curing temperatures of 230-380 °C led to an increase in the Tg of 34 °C.
  • Publication
    Gas sorption isotherms in swelling glassy polymers - detailed atomistic simulations
    ( 2013)
    Hölck, Ole
    ;
    Böhning, Martin
    ;
    Heuchel, Matthias
    ;
    Siegert, Martin R.
    ;
    Hofmann, Dieter
    Detailed atomistic simulations were carried out for swelling polymer/gas systems related to experimental sorption and dilation data for CO2 and CH4 in three glassy polymers (polysulfone PSU, the polyimide 6FDA-TrMPD, and a polymer of intrinsic microporosity PIM-1) at 308 K (35 °C) and pressures up to 50 bar. Corresponding experiments were performed with a gravimetric sorption balance and a dilatometer based on a capacitance distance sensor. For each polymer/gas system molecular packing models were prepared and equilibrated for two reference states: the pure polymer is taken as reference for the respective "unswollen" state and similarly the state of the highest penetrant pressure reached in the corresponding experiment is taken to represent the "swollen" state. Models for the latter were constructed in agreement with experimental data (pressure, temperature, gas concentration and volume dilation). Concentration-pressure isotherms of each polymer/gas system were obtained using Grand Canonical Monte Carlo (GCMC) simulations for both reference states (depleted of gas molecules), which are in good agreement with the experimental data in the respective pressure range. As expected these isotherms - due to the simulation technique used, merely based on hole-filling in a static host matrix - do not represent the sorption behavior over a broader range of gas pressures which may involve significant structural rearrangements as well as swelling and relaxational phenomena. Nevertheless, a linear combination of the two GCMC-isotherms allows the interpolation in order to describe the nonlinear gas sorption in the glassy polymers under investigation covering the penetrant pressure range between the reference states in good agreement with the experimental results.
  • Patent
    Faseroptischer Sensor und Verfahren zur Herstellung
    ( 2009)
    Schröder, H.
    ;
    Schmälzlin, E.
    ;
    Löhmannsröben, H.-G.
    (A1) Die vorliegende Erfindung betrifft einen faseroptischen Sensor sowie ein Verfahren zu dessen Herstellung. Der faseroptische Sensor weist eine optische Faser mit einem Faserkern auf, in deren Stirnflaeche eine bezueglich der optischen Achse des Faserkerns zentrierte Vertiefung eingebracht ist. In der Vertiefung ist eine Mikrokugel fixiert, die den Sensorfarbstoff traegt. Die Vertiefung sorgt dabei fuer die Zentrierung der Mikrokugel zur optischen Achse, so dass eine hohe Kopplungseffizienz fuer Licht erreicht wird, das vom Sensormaterial ausgeht. Durch die Mikrokugel in der Vertiefung wird auch ein robuster Aufbau erreicht, so dass die Gefahr einer mechanischen Beschaedigung des Sensors beim Einstecken in Proben verringert ist.
  • Publication
    Licht ins Dunkel der Elektronikverkapselung
    ( 2009)
    Schreier-Alt, T.
    ;
    Ansorge, F.
    Faseroptische Bragg-Gitter und innovative Werkzeuginnendrucksensoren ermöglichen die Belastungsanalyse in zentralen Prozessschritten der Elektronikverkapselung, und zwar vom Einspritzen des Polymers über das Auswerfen aus dem Werkzeug bis hin zum Materialschrumpf. Kombiniert mit numerischer Simulation gestatten sie Einblicke in das Verhalten des Polymers bei Zuverlässigkeitstests.
  • Publication
    Throwing light on electronics encapsulation
    ( 2009)
    Schreier-Alt, T.
    ;
    Anscirse, F.
    Fiber optic Bragg gratings (FBG) and innovative sensors for internal mold pressure are being used for load analysis in the process of electronics encapsulation. Along with numerical simulation, they are able to provide insights into polymer behavior during reliability testing. FBGs are capable of providing characterization of various plastics encapsulation processes. These sensors can be useful for load analysis on encapsulated electronics components and provide significant information of the production process, which are impossible with other sensors. The embedded fiber sensors can also be used for determining the gel and glass transition point during the production process, which further enables optimization of curing profiles in terms of stress minimization and process duration. These fiber sensors also have the ability to detect and predict structural damages.
  • Publication
    Highly integrated polymer-based technology platform for in-vitro diagnostics
    ( 2008)
    Otto, Thomas
    ;
    Nestler, Jörg
    ;
    Morschhauser, Andreas
    ;
    Schüller, Martin
    ;
    Geßner, T.
    ;
    Krissler, Jan
    ;
    Ebling, Frank
    ;
    Wegener, Michael
    ;
    Grzesiak, Andrzej
    ;
    Burgard, Matthias
    ;
    Brandenburg, Albrecht
    ;
    Sulz, Gerd
    ;
    Nebling, Eric
    ;
    Hintsche, Rainer
    ;
    Wirth, Ingo
    ;
    Godlinski, Dirk
    ;
    Tovar, Günter E.M.
    ;
    Weber, Achim
    ;
    Ehrentreich-Förster, Eva
    ;
    Gajovic-Eichelmann, Nenad
    ;
    Bier, Frank F.
    Systems for in-vitro diagnostics are of great interest especially in the point-of-care diagnostic market. Specialized integrated approaches have already been developed and successfully marketed, but were mainly focused on basic blood parameter determination. This paper describes a new, more flexible approach for an in-vitro diagnostic cartridge, which is able to hold different types of sensors (optical and electrochemical), integrated reagents as well as integrated microfluidic actuators. The platform will be capable of running both protein and nucleic acid analysis.
  • Patent
    Elektrisch steuerbare Anzeigevorrichung mit elektrisch beheizbarer thermochromer Schicht
    ( 2007)
    Yacoub-George, E.
    ;
    Klink, G.
    ;
    Seeboth, A.
    Die vorliegende Erfindung bezieht sich auf eine elektrisch ansteuerbare Anzeigevorrichtung zum Anzeigen einer darzustellenden Struktur. Insbesondere bezieht sich die vorliegende Erfindung auf eine Anzeigevorrichtung, bei der auf einem Traeger mindestens eine thermochrome Schicht aufgebracht ist, die bei unterschiedlichen Temperaturen unterschiedliche optische Eigenschaften hat. Um eine verbesserte elektrische steuerbare Anzeigevorrichtung auf der Basis thermochromer Schichten anzugeben, die aktiv ansteuerbar ist, eine groesstmoegliche Flexibilitaet bei der Konzipierung und eine kostenguenstige Herstellbarkeit bietet, weist die Anzeigevorrichtung weiterhin mindestens ein elektrisches Heizelement zum Heizen definierter Bereiche der Anzeigevorrichtung auf, wobei die geometrische Form der darzustellenden Struktur durch die Form des mindestens einen Heizelements definiert ist.
  • Publication
    Lightweight construction: Sandwiches with nap cores
    ( 2006)
    Bauer, M.
    ;
    Friede, P.
    ;
    Uhlig, C.