@inproceedings{9960, abstract = {{Ultrasonic wire bonding is a common technology for connecting electrodes of electronic components like power modules. Nowadays, bond connections are often made of copper instead of aluminum due to its thermal and mechanical assets. One of the main cost factors in the wire bonding process is the acquisition cost of consumables such as bonding tools. For copper wire bonding tool lifetime is much lower than for aluminium bonding. This paper presents a micro wear model for wedge/wedge bonding tools that was validated by observing wear patterns with a scanning electron microscope. The wear coefficient is determined in long-term bonding tests. The application of Fleischer´s wear approach incorporating frictional power to a finite element simulation of the bonding processes is used to shift element nodes depending on the rising frictional power for finite element modeling. The presented simulation method can be used to take tool wear into consideration for creating tools with increased lifetime. This enables the production of reliable bond connections using heavy as well as thin wire of any material. The paper discusses the predominant influences of wear on the main tool functions and their changes over tool life. Furthermore, the influence of the tool groove angle on the tool wear was investigated. One of the main results is that the wear is largest during the last phase of each bonding process, when the contact area between tool and wire is largest.}}, author = {{Eichwald, Paul and Unger, Andreas and Eacock, Florian and Althoff, Simon and Sextro, Walter and Guth, Karsten and Brökelmann, Michael}}, booktitle = {{IEEE CPMT Symposium Japan, 2016}}, title = {{{Micro Wear Modeling in Copper Wire Wedge Bonding}}}, year = {{2016}}, } @inproceedings{9961, abstract = {{Redundancy is a common approach to improve system reliability, availability and safety in technical systems. It is achieved by adding functionally equivalent elements that enable the system to remain operational even though one or more of those elements fail. This paper begins with an overview on the various terminologies and methods for redundancy concepts that can be modeled sufficiently using established reliability analysis methods. However, these approaches yield very complex system models, which limits their applicability. In current research, Bayesian Networks (BNs), especially Dynamic Bayesian Networks (DBNs) have been successfully used for reliability analysis because of their benefits in modeling complex systems and in representing multi-state variables. However, these approaches lack appropriate methods to model all commonly used redundancy concepts. To overcome this limitation, three different modeling approaches based on BNs and DBNs are described in this paper. Addressing those approaches, the benefits and limitations of BNs and DBNs for modeling reliability of redundant technical systems are discussed and evaluated.}}, author = {{Kaul, Thorben and Meyer, Tobias and Sextro, Walter}}, booktitle = {{Proceedings of the Third European Conference of the Prognostics and Health Management Society 2016}}, title = {{{Modeling of Complex Redundancy in Technical Systems with Bayesian Networks}}}, year = {{2016}}, } @inproceedings{9963, abstract = {{Tire-wheel assembly is the only connection between road and vehicle. Contacting directly with road within postcard size of contact area, it is mounted and guided by the suspension system. Therefore kinematics and compliances of suspension system greatly influence the frictional coupling of tire tread elements and road surface asperities by affecting pressure and sliding velocity distribution in the contact zone. This study emphasizes the development of a numerical methodology for frictional rolling contact analysis with focus on interaction of suspension system dynamics and tire-road contact using ADAMS. For this purpose a comprehensive flexible multibody system of the multi-link rear suspension is established, where both flexible and rigid bodies are modeled to allow large displacements with included elastic effects. To meet accuracy requirements for the high frequency applications, such as road excitations, the amplitude- and frequency-dependency of rubber-metal bushings is included. Furthermore the proposed flexible viscoelastic suspension model is enhanced by a Flexible Ring Tire Model (FTire), which describes a 3D tire dynamic response and covers any road excitations by tread submodel connected to road surface model. Concerning the verification and validation procedure numerous experiments are carried out to confirm the validity and the accuracy of both the developed submodels and the entire model. The devised approach makes it possible to investigate the influence of suspension system design on dynamical rolling contact and to evaluate tire tread wear. Therefore it can be a useful tool to predict frictional power distribution within the contact area under more realistic conditions.}}, author = {{Kohl, Sergej and Sextro, Walter and Schulze, Sebastian}}, booktitle = {{The 2nd International Conference on Automotive Innovation and Green Energy Vehicle (AiGEV 2016), Cyberjaya, Malaysia, 2016.}}, keywords = {{Kinematics and compliances, flexible viscoelastic suspension model, frictional rolling contact analysis, frictional power distribution.}}, pages = {{1--12}}, title = {{{Aspects of Flexible Viscoelastic Suspension Modeling for Frictional Rolling Contact Analysis using ADAMS}}}, year = {{2016}}, } @inproceedings{9964, abstract = {{This paper presents a benchmark data set for condition monitoring of rolling bearings in combination with an extensive description of the corresponding bearing damage, the data set generation by experiments and results of datadriven classifications used as a diagnostic method. The diagnostic method uses the motor current signal of an electromechanical drive system for bearing diagnostic. The advantage of this approach in general is that no additional sensors are required, as current measurements can be performed in existing frequency inverters. This will help to reduce the cost of future condition monitoring systems. A particular novelty of the present approach is the monitoring of damage in external bearings which are installed in the drive system but outside the electric motor. Nevertheless, the motor current signal is used as input for the detection of the damage. Moreover, a wide distribution of bearing damage is considered for the benchmark data set. The results of the classifications show that the motor current signal can be used to identify and classify bearing damage within the drive system. However, the classification accuracy is still low compared to classifications based on vibration signals. Further, dependency on properties of those bearing damage that were used for the generation of training data are observed, because training with data of artificially generated and real bearing damages lead to different accuracies. Altogether a verified and systematically generated data set is presented and published online for further research}}, author = {{Lessmeier, Christian and Kimotho, James Kuria and Zimmer, Detmar and Sextro, Walter}}, booktitle = {{European Conference of the Prognostics and Health Management Society}}, title = {{{Condition Monitoring of Bearing Damage in Electromechanical Drive Systems by Using Motor Current Signals of Electric Motors: A Benchmark Data Set for Data-Driven Classification}}}, year = {{2016}}, } @inproceedings{9966, abstract = {{Usage of copper wire bonds allows to push power boundaries imposed by aluminum wire bonds. Copper allows higher electrical, thermal and mechanical loads than aluminum, which currently is the most commonly used material in heavy wire bonding. This is the main driving factor for increased usage of copper in high power applications such as wind turbines, locomotives or electric vehicles. At the same time, usage of copper also increases tool wear and reduces the range of parameter values for a stable process, making the process more challenging. To overcome these drawbacks, parameter adaptation at runtime using self-optimization is desired. A self-optimizing system is based on system objectives that evaluate and quantify system performance. System parameters can be changed at runtime such that pre-selected objective values are reached. For adaptation of bond process parameters, model-based self-optimization is employed. Since it is based on a model of the system, the bond process was modeled. In addition to static model parameters such as wire and substrate material properties and vibration characteristics of transducer and tool, variable model inputs are process parameters. Main simulation result is bonded area in the wiresubstrate contact. This model is then used to find valid and optimal working points before operation. The working point is composed of normal force and ultrasonic voltage trajectories, which are usually determined experimentally. Instead, multiobjective optimalization is used to compute trajectories that simultaneously optimize bond quality, process duration, tool wear and probability of tool-substrate contacts. The values of these objectives are computed using the process model. At runtime, selection among pre-determined optimal working points is sufficient to prioritize individual objectives. This way, the computationally expensive process of numerically solving a multiobjective optimal control problem and the demanding high speed bonding process are separated. To evaluate to what extent the pre-defined goals of self-optimization are met, an offthe- shelf heavy wire bonding machine was modified to allow for parameter adaptation and for transmitting of measurement data at runtime. This data is received by an external computer system and evaluated to select a new working point. Then, new process parameters are sent to the modified bonding machine for use for subsequent bonds. With these components, a full self-optimizing system has been implemented.}}, author = {{Meyer , Tobias and Unger, Andreas and Althoff, Simon and Sextro, Walter and Brökelmann, Michael and Hunstig, Matthias and Guth, Karsten}}, booktitle = {{IEEE 66th Electronic Components and Technology Conference}}, keywords = {{Self-optimization, adaptive system, bond process, copper wire}}, pages = {{622--628}}, title = {{{Reliable Manufacturing of Heavy Copper Wire Bonds Using Online Parameter Adaptation}}}, doi = {{10.1109/ECTC.2016.215}}, year = {{2016}}, } @inproceedings{9967, abstract = {{Multibody models of mechatronic systems are usually interdisciplinary and are continuously gaining complexity, due to a growing demand for comprehensive models of systems including effects of electro mechanics, elastic bodies, contacts and friction. To be capable of simulating large models with subassemblies and contact between bodies, reduction techniques are required, which need certain experience in the choice of parameters. This publication discusses different possibilities for the modal description of structures in flexible multibody models with application to an Adaptive Frontlighting System in ADAMS. It will be shown that mode count, assembling of structures before and after modal reduction and influence of damping parameters of particular structures and subassemblies affect the behavior of the entire system. A common reduction technique for flexible structures in multibody models is the component mode synthesis, which uses a certain number of modes for description of the modal behavior of a structure. The influence of the mode count will be shown by means of different modal descriptions of one structure that contributes to a comprehensive model. Another study will prove that modal data of subassemblies and assemblies of modal reduced single structures lead to different models. The definition of damping parameters depends on the number of structures that have been added to an assembly before modal reduction and on the number of modal reduced structures. The comparison of subassemblies and the entire model to experimental data will highlight the accuracy, computational overhead, complexity of models and modeling efficiency of the comprehensive model for the frontlighting system.}}, author = {{Schulze, Sebastian and Sextro, Walter and Kohl, Sergej}}, booktitle = {{2nd International Conference on Automotive Innovation and Green Energy Vehicle (AiGEV) Malaysia 2016}}, keywords = {{model reduction, modal description, flexible multibody systems}}, pages = {{1--11}}, title = {{{Using Adequate Reduced Models for Flexible Multibody Systems of Automotive Mechatronic Systems}}}, year = {{2016}}, } @inproceedings{9968, abstract = {{To increase quality and reliability of copper wire bonds, self-optimization is a promising technique. For the implementation of self-optimization for ultrasonic heavy copper wire bonding machines, a model of stick-slip motion between tool and wire and between wire and substrate during the bonding process is essential. Investigations confirm that both of these contacts do indeed show stick-slip movement in each period oscillation. In a first step, this paper shows the importance of modeling the stick-slip effect by determining, monitoring and analyzing amplitudes and phase angles of tooltip, wire and substrate experimentally during bonding via laser measurements. In a second step, the paper presents a dynamic model which has been parameterized using an iterative numerical parameter identification method. This model includes Archard’s wear approach in order to compute the lost volume of tool tip due to wear over the entire process time. A validation of the model by comparing measured and calculated amplitudes of tool tip and wire reveals high model quality. Then it is then possible to calculate the lifetime of the tool for different process parameters, i.e. values of normal force and ultrasonic voltage.}}, author = {{Unger, Andreas and Schemmel, Reinhard and Meyer, Tobias and Eacock, Florian and Eichwald, Paul and Althoff, Simon and Sextro, Walter and Brökelmann, Michael and Hunstig, Matthias and Guth, Karsten}}, booktitle = {{Wear Modeling in Copper Wire Wedge Bonding. IEEE CPMT Symposium Japan, 2016}}, keywords = {{the Ultrasonic Wire Bonding Process}}, pages = {{251--254}}, title = {{{Validated Simulation of the Ultrasonic Wire Bonding Process}}}, year = {{2016}}, } @inproceedings{3934, abstract = {{Typical optical integrated circuits combine elements, like straight and curved waveguides, or cavities, the simulation and design of which is well established through numerical eigenproblem-solvers. It remains to predict the interaction of these modes. We address this task by a ”Hybrid” variant (HCMT) of Coupled Mode Theory. Using methods from finite-element numerics, the optical properties of a circuit are approximated by superpositions of eigen-solutions for its constituents, leading to quantitative, low-dimensional, and interpretable models in the frequency domain. Spectral scans are complemented by the direct computation of supermode properties (spectral positions and linewidths, coupling-induced phase shifts). This contribution outlines the theoretical background, and discusses briefly limitations and implementational details, with the help of an example of a 2-D coupled-resonator-optical-waveguide configuration.}}, author = {{Hammer, Manfred}}, booktitle = {{Integrated Optics: Devices, Materials, and Technologies XX}}, editor = {{Broquin, Jean-Emmanuel and Nunzi Conti, Gualtiero}}, keywords = {{tet_topic_waveguide, tet_topic_numerics}}, location = {{San Francisco, USA}}, number = {{9750}}, pages = {{975018--975018--8 }}, publisher = {{SPIE}}, title = {{{Wave interaction in photonic integrated circuits: Hybrid analytical / numerical coupled mode modeling}}}, doi = {{10.1117/12.2214331}}, year = {{2016}}, } @article{3956, abstract = {{In this article we present an integration technique for low-voltage DNTT-based TFTs for flexible electronic applications. Therefore, a high-k nanocomposite combining the flexibility of its polymericmatrix and the high permittivity of the incorporated inorganic material was used as gate dielectric layer. The influence of a conventional photolithography process upon the dielectric layer is analyzed regarding electrical instabilities in the device characteristics. The impact of an implemented sacrificial layer to reduce chemical stress to the insulating film during photolithography is evaluated. Furthermore, first inverter circuits were integrated and electrically characterized. Additionally, the implementation of this sacrificial layer can be used for future complementary circuit design.}}, author = {{Meyers, Thorsten and Vidor, Fábio F. and Brassat, Katharina and Lindner, Jörg and Hilleringmann, Ulrich}}, issn = {{0167-9317}}, journal = {{Microelectronic Engineering}}, pages = {{35--39}}, publisher = {{Elsevier BV}}, title = {{{Low-voltage DNTT-based thin-film transistors and inverters for flexible electronics}}}, doi = {{10.1016/j.mee.2016.12.018}}, volume = {{174}}, year = {{2016}}, } @inproceedings{4004, author = {{Brassat, Katharina and Rüdiger, Arne and Bürger, Julius and Bremser, W. and Strube, Oliver and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Enzyme mediated autodeposition of protein particles on nanosphere lithographically nanostructured surfaces }}}, year = {{2016}}, } @inproceedings{4005, author = {{Brassat, Katharina and Bürger, Julius and Reinecke, Melanie and Briese, Dennis and Duschik, K. and Schaper, Mirko and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Arrangement of perovskitic semiconductor nanoparticles using soft lithography }}}, year = {{2016}}, } @inproceedings{4006, author = {{Brassat, Katharina and Rüdiger, Arne and Bürger, Julius and Bremser, W. and Strube, O. and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Site-selective protein immobilization on regular antidot patterns fabricated by nanosphere lithography }}}, year = {{2016}}, } @inproceedings{4007, author = {{Brassat, Katharina and Kool, Daniel and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Hierarchically ordered nanopore structures formed by combined nanosphere and block copolymer lithography }}}, year = {{2016}}, } @inproceedings{4008, author = {{Brassat, Katharina and Lindner, Jörg}}, location = {{Porquerolles (France)}}, title = {{{Sub-20 nm surface patterning by block copolymer lithography }}}, year = {{2016}}, } @inproceedings{4009, author = {{Brodehl, Christoph and Greulich-Weber, Siegmund and Lindner, Jörg}}, location = {{Lille (France)}}, title = {{{Fabricating metasurface-based optical devices with a low-cost technique}}}, year = {{2016}}, } @inproceedings{4010, author = {{Puglisi, R.A. and Bongiorno, C. and Brassat, Katharina and Garozzo, Christina and La Magna, A. and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{High-resolution TEM and STEM-EELS studies of colloidal Au nanoparticles self-assembled in nanometric SiO2 nanopore arrays fabricated by block-copolymer lithography }}}, year = {{2016}}, } @inproceedings{4011, author = {{Riedl, Thomas and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Automated SEM image analysis of the opening size distribution of nanosphere lithography masks and their origins }}}, year = {{2016}}, } @inproceedings{4012, author = {{Riedl, Thomas and Lindner, Jörg}}, location = {{Regensburg (Germany)}}, title = {{{Theoretical analysis of strain and misfit dislocation stability in axial-heteroepitaxial GaAs/InAs nanopillars}}}, year = {{2016}}, } @inproceedings{4013, author = {{Riedl, Thomas and Kemper, R.M. and As, Donald and Lindner, Jörg}}, location = {{Regensburg}}, title = {{{Stability of misfit dislocations in axial-heteroepitaxial 3CSiC/c-GaN nanopillars and nanomesas}}}, year = {{2016}}, } @inproceedings{4014, author = {{Rieger, T. and Riedl, Thomas and Lindner, Jörg and Pawlis, A.}}, location = {{Montpellier (France)}}, title = {{{Enhancement of the critical thickness of CdSe/ZnSe quantum wells via the strain compensation technique}}}, year = {{2016}}, }