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Bernd Roelfs - One of the best experts on this subject based on the ideXlab platform.

  • High Aspect Ratio Package Core Production with Electrolytic Deposited Copper
    2010
    Co-Authors: Stephen Kenny, Bernd Roelfs
    Abstract:

    A typical Package Core consists of copper clad dielectric which is drilled to produce the necessary through vias serving two functions either as electrical or as thermal conduits. The thermal vias are normally characterised by a low drill pitch and a localisation at the centre of the Package Core. The vias are plugged after metallisation with a resin material to give the Core the required planar surface necessary to provide the basis for the subsequent build up layers. Use of electrolytic deposited copper has been introduced as a new method to fill such through vias, pure copper as a plugging material has obvious advantages due its higher thermal conductivity in comparison to any currently available plugging resins. Significant cost savings are also possible as a fully automated in line processing sequence is available for electrolytic copper deposition in comparison to the more labour intensive resin plugging methods. The Package Cores utilising this technology have however been restricted to a dielectri...

  • High Aspect Ratio Package Core Production with Electrolytic Deposited Copper
    International Symposium on Microelectronics, 2010
    Co-Authors: Stephen Kenny, Bernd Roelfs
    Abstract:

    A typical Package Core consists of copper clad dielectric which is drilled to produce the necessary through vias serving two functions either as electrical or as thermal conduits. The thermal vias are normally characterised by a low drill pitch and a localisation at the centre of the Package Core. The vias are plugged after metallisation with a resin material to give the Core the required planar surface necessary to provide the basis for the subsequent build up layers. Use of electrolytic deposited copper has been introduced as a new method to fill such through vias, pure copper as a plugging material has obvious advantages due its higher thermal conductivity in comparison to any currently available plugging resins. Significant cost savings are also possible as a fully automated in line processing sequence is available for electrolytic copper deposition in comparison to the more labour intensive resin plugging methods. The Package Cores utilising this technology have however been restricted to a dielectric thickness in the range 60μm to 100μm and with through via diameter 75μm to 100μm due to limitations in the processing technology. With these dimensions a hole pitch of down to 250μm may be filled reliably and is currently in production, latest results from this technology are shown. Hole filling with higher aspect ratios and particularly with substrates thicker than 200μm has required improvements in processing to ensure uniform copper filling. This paper describes the optimised process for through hole filling and shows the results achieved with dielectric materials 200μm and up to 400μm thick. Current qualification results of substrate 400μm thick with through via 80μm diameter are shown together with the comparison of filling with via pitch variation between 1.0mm and 0.6mm

Stephen Kenny - One of the best experts on this subject based on the ideXlab platform.

  • High Aspect Ratio Package Core Production with Electrolytic Deposited Copper
    2010
    Co-Authors: Stephen Kenny, Bernd Roelfs
    Abstract:

    A typical Package Core consists of copper clad dielectric which is drilled to produce the necessary through vias serving two functions either as electrical or as thermal conduits. The thermal vias are normally characterised by a low drill pitch and a localisation at the centre of the Package Core. The vias are plugged after metallisation with a resin material to give the Core the required planar surface necessary to provide the basis for the subsequent build up layers. Use of electrolytic deposited copper has been introduced as a new method to fill such through vias, pure copper as a plugging material has obvious advantages due its higher thermal conductivity in comparison to any currently available plugging resins. Significant cost savings are also possible as a fully automated in line processing sequence is available for electrolytic copper deposition in comparison to the more labour intensive resin plugging methods. The Package Cores utilising this technology have however been restricted to a dielectri...

  • High Aspect Ratio Package Core Production with Electrolytic Deposited Copper
    International Symposium on Microelectronics, 2010
    Co-Authors: Stephen Kenny, Bernd Roelfs
    Abstract:

    A typical Package Core consists of copper clad dielectric which is drilled to produce the necessary through vias serving two functions either as electrical or as thermal conduits. The thermal vias are normally characterised by a low drill pitch and a localisation at the centre of the Package Core. The vias are plugged after metallisation with a resin material to give the Core the required planar surface necessary to provide the basis for the subsequent build up layers. Use of electrolytic deposited copper has been introduced as a new method to fill such through vias, pure copper as a plugging material has obvious advantages due its higher thermal conductivity in comparison to any currently available plugging resins. Significant cost savings are also possible as a fully automated in line processing sequence is available for electrolytic copper deposition in comparison to the more labour intensive resin plugging methods. The Package Cores utilising this technology have however been restricted to a dielectric thickness in the range 60μm to 100μm and with through via diameter 75μm to 100μm due to limitations in the processing technology. With these dimensions a hole pitch of down to 250μm may be filled reliably and is currently in production, latest results from this technology are shown. Hole filling with higher aspect ratios and particularly with substrates thicker than 200μm has required improvements in processing to ensure uniform copper filling. This paper describes the optimised process for through hole filling and shows the results achieved with dielectric materials 200μm and up to 400μm thick. Current qualification results of substrate 400μm thick with through via 80μm diameter are shown together with the comparison of filling with via pitch variation between 1.0mm and 0.6mm

F. Courtin - One of the best experts on this subject based on the ideXlab platform.

  • The Impact of Reactor Model Simplification for Fuel Evolution: A Bias Quantification for Fuel Cycle Dynamic Simulations
    2016
    Co-Authors: A. Somaini, S. David, X. Doligez, A.a. Zakari-issoufou, A. Bidaud, N. Cappelan, O. Meplan, A. Nuttin, P. Prevot, F. Courtin
    Abstract:

    In nuclear scenario studies, the use of simplified assembly models to simulate fuel irradiation in nuclear reactor Core can lead to important biases. To calculate the spent fuel composition, the CLASS Package (Core Library for Advanced Scenario Simulations) uses a physic model (usually, we define physics model as: 1- Fuel Loading Model, 2- Cross Section Predictor, 3- Bateman Solver), based on a large number of different fuel evolution simulations. For that, a simple and reproducible model has been chosen: the “assembly model” that is described in this paper. In this model, the whole Core is represented by a single assembly, or a part of it, with reflecting boundary conditions. As a first step to quantify the errors related to this approximation, three real size assembly configurations have been simulated: a reflected one, an axial open one and a realistic one (with moderator and reflector at its top and bottom). An exhaustive comparison is presented in this paper. Hence this work focuses on the neutron axial leakage impact on burn-up and isotope inventories calculations. Evolutions up to 50 GWd/t have been simulated with the depletion code MURE for all the geometries and main isotope inventories, fission and capture cross sections and Keff have been reported for each time step. Axial leakage effects on neutron spectrum and inventory distributions have been observed. In this paper, a bias quantification of axial leakage and a comparison with homogeneous leakage models, available in the Serpent code, are analyzed.

A. Somaini - One of the best experts on this subject based on the ideXlab platform.

  • The Impact of Reactor Model Simplification for Fuel Evolution: A Bias Quantification for Fuel Cycle Dynamic Simulations
    2016
    Co-Authors: A. Somaini, S. David, X. Doligez, A.a. Zakari-issoufou, A. Bidaud, N. Cappelan, O. Meplan, A. Nuttin, P. Prevot, F. Courtin
    Abstract:

    In nuclear scenario studies, the use of simplified assembly models to simulate fuel irradiation in nuclear reactor Core can lead to important biases. To calculate the spent fuel composition, the CLASS Package (Core Library for Advanced Scenario Simulations) uses a physic model (usually, we define physics model as: 1- Fuel Loading Model, 2- Cross Section Predictor, 3- Bateman Solver), based on a large number of different fuel evolution simulations. For that, a simple and reproducible model has been chosen: the “assembly model” that is described in this paper. In this model, the whole Core is represented by a single assembly, or a part of it, with reflecting boundary conditions. As a first step to quantify the errors related to this approximation, three real size assembly configurations have been simulated: a reflected one, an axial open one and a realistic one (with moderator and reflector at its top and bottom). An exhaustive comparison is presented in this paper. Hence this work focuses on the neutron axial leakage impact on burn-up and isotope inventories calculations. Evolutions up to 50 GWd/t have been simulated with the depletion code MURE for all the geometries and main isotope inventories, fission and capture cross sections and Keff have been reported for each time step. Axial leakage effects on neutron spectrum and inventory distributions have been observed. In this paper, a bias quantification of axial leakage and a comparison with homogeneous leakage models, available in the Serpent code, are analyzed.

Kamran Sepanloo - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of the Core configuration design using a hybrid artificial intelligence algorithm for research reactors
    Nuclear Engineering and Design, 2009
    Co-Authors: Afshin Hedayat, H. Davilu, Ahmad Abdollahzadeh Barfrosh, Kamran Sepanloo
    Abstract:

    To successfully carry out material irradiation experiments and radioisotope productions, a high thermal neutron flux at irradiation box over a desired life time of a Core configuration is needed. On the other hand, reactor safety and operational constraints must be preserved during Core configuration selection. Two main objectives and two safety and operational constraints are suggested to optimize reactor Core configuration design. Suggested parameters and conditions are considered as two separate fitness functions composed of two main objectives and two penalty functions. This is a constrained and combinatorial type of a multi-objective optimization problem. In this paper, a fast and effective hybrid artificial intelligence algorithm is introduced and developed to reach a Pareto optimal set. The hybrid algorithm is composed of a fast and elitist multi-objective genetic algorithm (GA) and a fast fitness function evaluating system based on the cascade feed forward artificial neural networks (ANNs). A specific GA representation of Core configuration and also special GA operators are introduced and used to overcome the combinatorial constraints of this optimization problem. A software Package (Core Pattern Calculator 1) is developed to prepare and reform required data for ANNs training and also to revise the optimization results. Some practical test parameters and conditions are suggested to adjust main parameters of the hybrid algorithm. Results show that introduced ANNs can be trained and estimate selected Core parameters of a research reactor very quickly. It improves effectively optimization process. Final optimization results show that a uniform and dense diversity of Pareto fronts are gained over a wide range of fitness function values. To take a more careful selection of Pareto optimal solutions, a revision system is introduced and used. The revision of gained Pareto optimal set is performed by using developed software Package. Also some secondary operational and safety terms are suggested to help for final trade-off. Results show that the selected benchmark case study is dominated by gained Pareto fronts according to the main objectives while safety and operational constraints are preserved.