Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM

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Now showing 1 - 10 of 334
  • Publication
    A Novel Quantitative Adhesion Measurement Method for Thin Polymer and Metal Layers for Microelectronic Applications
    ( 2022)
    Woehrmann, Markus
    ;
    Mackowiak, Piotr
    ;
    Schiffer, Michael
    ;
    Lang, K.-D.
    ;
    Schneider-Ramelow, M.
    Advancements in packaging technologies like Fan-Out demand for a higher integration density with an increased number of RDL layers as well as novel low-k layers as interlayer dielectric. The adhesion of these layers becomes an important factor for the reliability of the packaging because an enforcement by mechanical bond is limited. This work presents a novel test method (Stripe Lift-Off Test - SLT) for the adhesion characterization of thin film layers used in RDL for Fan-In and Fan-Out. The method is based on a modified edge lift-off test (mELT) concept. A polymer layer under high tensile stress is used to force a delamination of a layer stack. A critical energy release rate (J/m2) leading to a delamination can be estimated based on the known biaxial stress in the stressing polymer. The usage of residual stress in a layer stack for driving a delamination avoids any additional clamping, gluing of additional layers or the demand of special adhesion measurement equipment. The quantified adhesion test can be integrated in any RDL production line since only coating equipment is needed as well as a dicing tool for sample generation. The sample generation complexity can be scaled regarding the purpose of the adhesion measurement - ranging from a quick, rough estimation and adhesion value evaluation in a production process to a precise prediction of the energy release rate that can be used as a basis for packaging simulation. The established mELT for the quantification of the interface's fracture toughness is limited by the fact that it is running at negative temperatures. The novelty of the SLT is a stress polymer layer with a modifiable stress state which allows the adhesion measurement at room temperature. The stress state can be tailored to investigate the delamination at a certain temperature related to the application. FE-modeling of the SLT in ANSYS is presented and these results are compared to the analytical energy release rate estimation of the SLT. These verified FEM fracture models form the basics for the integration of the SLT fracture toughness data into more complex reliability simulations of advanced packaging. Exemplary adhesion measurements are presented for polymer films as well as for sputter layers with different preconditioning.
  • Publication
    Investigation and Modeling of Etching Through Silicon Carbide Vias (TSiCV) for SiC Interposer and Deep SiC Etching for Harsh Environment MEMS by DoE
    ( 2022)
    Mackowiak, Piotr
    ;
    Erbacher, Kolja
    ;
    Schiffer, Michael
    ;
    Manier, Charles-Alix
    ;
    Töpper, Michael
    ;
    Ngo, H.-D.
    ;
    Schneider-Ramelow, M.
    ;
    Lang, K.-D.
    This article presents prime results on process development and optimization of dry etching of silicon carbide (SiC) for via formation and deep etching for SiC-based microsystems. The investigations and corresponding results of the process developments enable the first realization of a full SiC-based technological demonstrator composed of a SiC-interposer with a flip chip mounted deep etched micro electromechanical system (MEMS) SiC Device. By optimizing the process, etch depth of 200 μm with an etch rate of up to 2 μm /min can be achieved for via etching. In addition, a design of experiments (DoEs) with a total of 29 experiments with seven factors was done to characterize the deep etching of large areas into the SiC. Hereby, vertical sidewalls with low micromasking, low microtrenching and an etch rate of up to 4 μm /min could be achieved. The findings and optimized processes were implemented to develop on the one hand a 200- μm -thick SiC interposer with copper metallization. On the other hand, a SiC-MEMS Device was manufactured with a deep etched cavity in SiC bulk wafer forming by the end a 50- μm thin membrane. The results demonstrate the ability of etching monocrystalline SiC with a high etch rate, enabling new fundamental topologies/structures and packaging concepts for harsh environments MEMSs and high-power electronics. The developed etching technologies demonstrate and enable various applications for 3-D Integration with wide bandgap substrates taking advantage of the superior electrical and mechanical properties of SiC.
  • Publication
    RF Modeling and Measurement of a Novel Aperture-Coupled Hybrid Glass-Silicon 5G Antenna Array
    ( 2021)
    Le, T.H.
    ;
    Rossi, M.
    ;
    Ndip, I.
    ;
    Kaiser, M.
    ;
    Manier, C.-A.
    ;
    Gernhardt, R.
    ;
    Oppermann, H.
    ;
    Lang, K.-D.
    ;
    Reichl, H.
    In this work, the electromagnetic modelling and measurement of a novel aperture-coupled hybrid glass-silicon 1x2 antenna array is presented. The patch elements are located under a glass substrate, which is placed on a silicon layer. The antenna array is fed using aperture coupling. A cavity is etched in the silicon layer to reduce the impact of silicon, and thus ensures significant improvement of the antenna efficiency and gain. The proposed antenna was fabricated and measured. Very good correlation is obtained between simulation and measurement.
  • Publication
    Recent Advances and Challenges of Nanomaterials-Based Hydrogen Sensors
    ( 2021)
    Wang, B.
    ;
    Sun, L.
    ;
    Schneider-Ramelow, M.
    ;
    Lang, K.-D.
    ;
    Ngo, H.-D.
    Safety is a crucial issue in hydrogen energy applications due to the unique properties of hydrogen. Accordingly, a suitable hydrogen sensor for leakage detection must have at least high sensitivity and selectivity, rapid response/recovery, low power consumption and stable functionality, which requires further improvements on the available hydrogen sensors. In recent years, the mature development of nanomaterials engineering technologies, which facilitate the synthesis and modification of various materials, has opened up many possibilities for improving hydrogen sensing performance. Current research of hydrogen detection sensors based on both conservational and innovative materials are introduced in this review. This work mainly focuses on three material categories, i.e., transition metals, metal oxide semiconductors, and graphene and its derivatives. Different hydrogen sensing mechanisms, such as resistive, capacitive, optical and surface acoustic wave-based sensors, are also presented, and their sensing performances and influence based on different nanostructures and material combinations are compared and discussed, respectively. This review is concluded with a brief outlook and future development trends.
  • Publication
    Methodology for Modeling the Energy and Material Footprint of Future Telecommunication Networks
    ( 2021)
    Stobbe, L.
    ;
    Nissen, N.F.
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    Druschke, J.
    ;
    Zedel, H.
    ;
    Richter, N.
    ;
    Lang, K.-D.
    This paper presents important methodical aspects in conjunction with the ongoing development of a novel multi-level-model in support of lifecycle environmental assessments of telecommunication networks. The new approach is, to some extent, emulating the OSI-layer model (Open Systems Interconnection), starting at the bottom with the main physical components, followed by product configurations, network architecture and control. On the top layer, the model scales through application and use case scenarios. This complex inventory model furthermore distinguishes between constructive (hardware-defined) elements on the one hand and operational (software-defined) elements on the other. By combining technical data as fixed values with application data as variable values, it is now possible to analyze the causal interaction between different technology generations, network configurations, and utilization intensity. It will allow identifying the best starting point for eco-design and improvement measures. Due to fact that the new methodology is not limited to energy consumption only, it supports a holistic understanding of the environmental impact of telecommunication networks.
  • Publication
    Influence of Ball Size and Geometry on the Reliability and RF Performance of mmWave System-in-Package: A Simulation Approach
    ( 2021)
    Dilek, S.
    ;
    Ndip, I.
    ;
    Rossi, M.
    ;
    Tschoban, C.
    ;
    Kuttler, S.
    ;
    Wittler, O.
    ;
    Lang, K.-D.
    ;
    Goetze, C.
    ;
    Berger, D.
    ;
    Wieland, M.
    ;
    Schneider-Ramelow, M.
    Solder ball reliability is a long-discussed topic in microelectronic packaging. With new package types needed for mmWave applications a trade-off between reliability and RF performance may arise, when the solder ball geometry has to be selected for specific package assemblies. In this work, the lifetime for different solder ball geometries is investigated within a numerical simulation workflow, by means of a sensitivity analysis in which the ball diameter, pad sizes and stand-off distance are varied. Next to lifetime estimations, 3D full-wave simulations have been applied to analyze the RF performance of the structures under investigation at 77-79 GHz (E-band) center frequencies relevant for automotive radar applications. Finally, the trade-off between RF performance and reliability is illustrated and quantified.
  • Publication
    Investigation of Deep Dry Etching of 4H SIC Material for MEMS Applications Using DOE Modelling
    ( 2021)
    Erbacher, K.
    ;
    Mackowiak, P.
    ;
    Schiffer, M.
    ;
    Lang, K.-D.
    ;
    Schneider-Ramelow, M.
    ;
    Ngo, H.-D.
    In this paper the reactive ion etching (RIE) of 4H silicon carbide (SiC) with an SF 6 /O 2 /He gas mixture is investigated in an inductively coupled plasma etcher (ICP). Objective is the analysis of the manufacturing process of a SiC diaphragm for a bulk micromechanical pressure sensor, by etching a cavity into silicon carbide wafer. In addition, the selectivity of etching masks made from Nickel and Copper against SiC are examined. By means of Design of Experiments (DOE) in the software JMP, a test series with 29 recipes is set up. The process is varied over the parameters chamber pressure, source power, platen power, SF 6 flow rate, O 2 flow rate, clamp cooling and mask material. To evaluate the etched samples quantitatively, cross sections of 29 specimens are made. The results are used to create a mathematically model for the prediction of etching rate, profile angle and occurring micro masking. The model is evaluated by etching samples. Etching a cavity with an opening width of 800 mm to a depth of 300 mm with a maximum etching rate of 4 mm/min, vertical profile walls and a smooth and even etched base is demonstrated. The selectivity of the modelled process is 115 compared to Cu, the observed selectivity of Cu is higher compared to Ni.
  • Publication
    Ecological Cost-Benefit Analysis of a Sensor-Based Parking Prediction Service
    ( 2021)
    Druschke, J.
    ;
    Fath, S.
    ;
    Stobbe, L.
    ;
    Nissen, N.F.
    ;
    Richter, N.
    ;
    Lang, K.-D.
    The fast-growing sector of smart city applications resulting from the ongoing digitalization has a huge impact on our society. They use innovative technologies to improve for example mobility, optimize shopping or offer intelligent travel guide assistance. However, these applications have not only the potential to benefit our daily life with precisely targeted services, but also to reduce the environmental impact we create. In this paper the authors present the proceeding for a simplified life cycle assessment on the special case of a sensor-based parking prediction service of the Deutsche Telekom called "Park&Joy".
  • Publication
    Manufacturing of high frequency substrates as software programmable metasurfaces on PCBs with integrated controller nodes
    ( 2020)
    Manessis, D.
    ;
    Seckel, M.
    ;
    Fu, L.
    ;
    Tsilipakos, O.
    ;
    Pitilakis, A.
    ;
    Tasolamprou, A.
    ;
    Kossifos, K.
    ;
    Varnava, G.
    ;
    Liaskos, C.
    ;
    Kafesaki, M.
    ;
    Soukoulis, C.M.
    ;
    Tretyakov, S.
    ;
    Georgiou, J.
    ;
    Ostmann, A.
    ;
    Aschenbrenner, R.
    ;
    Schneider-Ramelow, M.
    ;
    Lang, K.-D.
    The proposed work is performed in the framework of the FET-EU project "VISORSURF", which has undertaken research activities on the emerging concepts of metamaterials that can be software programmable and adapt their properties. In the realm of electromagnetism (EM), the field of metasurfaces (MSF) has reached significant breakthroughs in correlating the micro- or nano-structure of artificial planar materials to their end properties. MSFs exhibit physical properties not found in nature, such as negative or smaller-than-unity refraction index, allowing for EM cloaking of objects, reflection cancellation from a given surface and EM energy concentration in as-tight-as-possible spaces.The VISORSURF main objective is the development of a hardware platform, the Hypersurface, whose electromagnetic behavior can be defined programmatically. The key enablers for this are the metasurfaces whose electromagnetic properties depend on their internal structure. The Hypersurface hardware platform will be a 4-layer build-up of high frequency PCB substrate materials and will merge the metasurfaces with custom electronic controller nodes at the bottom of the PCB hardware platform. These electronic controllers build a nanonetwork which receives external programmatic commands and alters the metasurface structure, yielding a desired electromagnetic behavior for the Hypersurface platform.This paper will elaborate on how large scale PCB technologies are deployed for the economical manufacturing of the 4-layer Hypersurface PCB hardware platform with a size of 9"x12", having copper metasurface patches on the top of the board and the electronic controllers as 2mmx2mm WLCSP chips at 400mm pitch assembled at the bottom of the platform. The PCB platform designs have stemmed from EM modeling iterations of the whole stack of high frequency laminates taking into account also the electronic features of the controller nodes. The manufacturing processes for the realization of the selected PCB architectures will be discussed in detail.
  • Publication
    Reliability Investigation of Ultra Fine Line, Multi-Layer Copper Routing for Fan-Out Packaging Using a Newly Designed Micro Tensile Test Method
    ( 2020)
    Woehrmann, M.
    ;
    Keller, A.
    ;
    Fritzsch, T.
    ;
    Schiffer, M.
    ;
    Gollhardt, A.
    ;
    Walter, H.
    ;
    Schneider-Ramelow, M.
    ;
    Lang, K.-D.
    Fan-Out enables new heterogeneous packaging concepts where chips are embedded in an electronic mold compound (EMC) package with ultra-small footprint. These multi-chip systems demand a high routing density in the redistribution layer (RDL) which is realized by fine copper features with line and space structures in the dimension down to 2 mu m, establishing electrical interconnects between the chips across different substrate materials (e.g. silicon chips and mold-filled gaps). The copper lines undergo high mechanical stress due different thermal expansion coefficients of the used materials. Numerous papers investigated reliability topics only focusing on properties of the polymer in the redistribution layer and the solder ball material, but the influence of the mechanical properties of electroplated copper has been a minor topic so far [1] [2] [3].With feature sizes and thicknesses of about 2 mu m, these structures are in the range of copper grain size with the result that different grain structures become more important. Also, the material suppliers start to tune galvanic copper baths to generate e.g. twinned copper structures with mechanically superior behavior. Characterizing these fine structures at that scale is challenging because the properties could be different compared to macro samples. This work presents an on-wafer characterization method of copper features down to 2 mu m with a newly designed wafer scale micro tensile test. This concept allows a test integration in the fab process flow. The elongation at break and the tensile strength of ultra fine line copper lines are measured by the tensile loading. The results are compared with macro scale tensile tests.