Determination of cyclic mechanical properties of thin copper layers for PCB applications

Fellner, Klaus; Fuchs, Peter; Antretter, Thomas; Pinter, Gerald; Schöngrundner, R.

doi:10.1109/eurosime.2014.6813788

Cited by 10 publications

(7 citation statements)

References 11 publications

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“…Further explanations on this procedure can be found elsewhere. 25 For the determination of the kinematic and isotropic hardening behavior, the following loading cases were considered ( Table 1). The force limits were reduced at higher temperatures to account for the lower material strength.…”

Section: Determination Of the Kinematic And Isotropic Hardening Behaviormentioning

confidence: 99%

“…Abaqus was used as ''user-defined solver''; a model of the test setup was implemented. 25 The difference between the experimentally determined values of the material parameter Q (see equation (3)) for every single loading case and the ones predicted by the strain range memorization model was used as residuum to be minimized. Q stands for the yield stress of the stabilized cycle.…”

Section: Evaluation Of Strain Range Dependencymentioning

confidence: 99%

“…The strain rate was kept constant for all experiments by adapting the circular frequency. All measured loading cases are listed in Fellner et al 25 The mechanical properties of the FR4-prepreg at 23 °C, 85 °C and 145 °C were determined in tensile tests on a Zwick Z250 (Zwick GmbH & Co. KG, Ulm, Germany) testing machine. Due to the thinness of the FR4-Prepreg, the mechanical properties perpendicular to the laminate plane could not be measured.…”

Section: Experimental Characterizationmentioning

confidence: 99%

“…31 The elastic properties of the copper foil were measured using a micro-dynamic mechanical analyzer. 25…”

Section: Experimental Characterizationmentioning

confidence: 99%

“…The kinematic and isotropic hardening behaviors were determined from the resulting hysteretic force-strain curves. 25 This information can be used as material input data for a ''Nonlinear isotropic/kinematic hardening model'' 26 which is based on Lemaitre and Chaboche 27 and Chaboche 28 and available in the finite element analysis (FEA)-software Abaqus (Abaqus 6.12; Simulia, Dassault Syste`mes, Ve´lizy-Villacoublay, France). The kinematic hardening parameters were fitted in an optimization process using LS-Opt (LSTC, Livermore, CA, USA, 2011) with Abaqus as user-defined solver.…”

Section: Introductionmentioning

confidence: 99%

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Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

Fellner

Antretter

Fuchs

et al. 2015

The Journal of Strain Analysis for Engineering Design

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In printed circuit boards, thin copper layers are used as current paths. During the thermal loading of printed circuit boards, stresses arise due to the different coefficients of thermal expansion of the used materials. To be able to model the mechanical behavior of printed circuit boards under cyclic thermal loads, cyclic mechanical tests of thin copper foils under changing tensile and compression loads at different temperatures were conducted. From these experiments, the isotropic and kinematic hardening parameters were determined serving as material input data for a nonlinear isotropic/ kinematic hardening model in the finite element analysis-software Abaqus. The kinematic hardening parameters were fitted in an optimization process. The isotropic hardening variables were determined based on the stress versus plastic strain relationship that was constructed incrementally from the available individual cycles. The so-obtained curve was found to be not unique, but to depend on the loading situation. Hence, different approaches for strain range memorization were evaluated. Since these approaches were developed for modeling strain-controlled tests, whereas the experimental data were obtained in a force-controlled way, a phenomenological formulation was developed and applied. The results of curvature measurements during thermal cycling were used for model validation. The experimental results and the numerical predictions are in good agreement.

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Section: Determination Of the Kinematic And Isotropic Hardening Behaviormentioning

confidence: 99%

Section: Evaluation Of Strain Range Dependencymentioning

confidence: 99%

Section: Experimental Characterizationmentioning

confidence: 99%

“…31 The elastic properties of the copper foil were measured using a micro-dynamic mechanical analyzer. 25…”

Section: Experimental Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

Fellner

Antretter

Fuchs

et al. 2015

The Journal of Strain Analysis for Engineering Design

Self Cite

View full text Add to dashboard Cite

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Numerical simulation of the electrical performance of printed circuit boards under cyclic thermal loads

Fellner

Antretter

Fuchs

et al. 2016

Microelectronics Reliability

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Electro-thermal-mechanical analyses on stress in silver sintered power modules with different copper interconnection technologies

Dudek

Döring

Hildebrandt

et al. 2016

2016 6th Electronic System-Integration Technology Conference (ESTC)

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Increasing demands for higher energy efficiency and operating at harsh environments lead to the development of new compact power electronics, which is complemented by new interconnection technologies. Investigations were made on a planar copper interconnection technology. The characteristic difference to other technologies can be seen in the replacement of bonding wires by planar copper interconnects and the high voltage applicability of the resulting modules. A high voltage and temperature resistant polymeric foil provides the insulation. Electrical connection is made by structured electrodeposited copper structures, which allow for additional heat spreading from top of the dies. Investigations on the thermo-mechanical behavior of prototype inverter modules, which use silver sintering and copper wire bonding technology or, alternatively, planar copper interconnection technology are reported. Fully coupled electrical-thermal-mechanical finite element (FE-) simulations w ere used to get realistic transient temperature loadings as well as mechanical stresses, also including wire heating or heating of the planar metallization, respectively. Improved thermal performance of the planar technology could be shown. A parametric FE-study was made to minimize delamination failure risks of planar structures based on cohesive zone modeling. Studies on processing dependent properties of the key materials sintered silver, electroplated copper, and dielectric foils are reported, which are indispensable for simulation input

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Determination of cyclic mechanical properties of thin copper layers for PCB applications

Cited by 10 publications

References 11 publications

Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

Numerical simulation of the electrical performance of printed circuit boards under cyclic thermal loads

Electro-thermal-mechanical analyses on stress in silver sintered power modules with different copper interconnection technologies

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