---
_id: '9959'
abstract:
- lang: eng
  text: Ultrasonic heavy wire bonding is a commonly used technology to conduct electrical
    devices in power electronics. In order to facilitate powerful solutions combined
    with an increased efficiency, involving a material change from aluminum to copper
    wire as conductor material takes place in recent years. Due to the material related
    properties, copper wire bonding requires significant higher bond processing parameters
    such as bond force and ultrasonic power compared to aluminum which can lead to
    damages or a failure of the bonded component. Therefore, a profound knowledge
    of the processes prevailing during wire bonding is essential to optimize the application
    of the copper wires and consequently to achieve the demands on quality and reliability.
    The behavior of different natural surface oxides of aluminum and copper are assumed
    to be one reason for the deviation in the required bond parameters. Accordingly,
    the impact of differently pre-treated substrates surfaces on which the bonding
    is applied were investigated in this study. First, all conditions investigated
    (as-received, oxidefree, AlOx and the CuOx) were characterized by utilizing scanning
    electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam microscopy
    and atomic force microscopy. In addition, hardness tests were performed as well
    as perthometer measurements. Afterwards, a 500 $\mu$ m copper wire was bonded
    on the generated surfaces investigated. In consideration of the roughness, shear
    test of various bond times and microscopic images were evaluated. Finally, the
    results were compared and discussed. Overall, the current study indicates that
    an Al-oxide layer is beneficial for welding process in Cu wire bonding. On the
    contrary, the Cu-oxide is detrimental and leads to a delayed welding of the joining
    parts. Based on the obtained results, it can be expected that due to an ideal
    set of Al-oxide layers, lower optimal bond parameters can used to reach high bond
    strength with good reliability properties.
author:
- first_name: Florian
  full_name: Eacock, Florian
  last_name: Eacock
- first_name: Andreas
  full_name: Unger, Andreas
  last_name: Unger
- first_name: Paul
  full_name: Eichwald, Paul
  last_name: Eichwald
- first_name: Olexandr
  full_name: Grydin, Olexandr
  last_name: Grydin
- first_name: Florian
  full_name: Hengsbach, Florian
  last_name: Hengsbach
- first_name: Simon
  full_name: Althoff, Simon
  last_name: Althoff
- first_name: Mirko
  full_name: Schaper, Mirko
  last_name: Schaper
- first_name: Karsten
  full_name: Guth, Karsten
  last_name: Guth
citation:
  ama: 'Eacock F, Unger A, Eichwald P, et al. Effect of different oxide layers on
    the ultrasonic copper wire bond process. In: <i>IEEE 66th Electronic Components
    and Technology Conference</i>. ; 2016:2111-2118. doi:<a href="https://doi.org/10.1109/ECTC.2016.91">10.1109/ECTC.2016.91</a>'
  apa: Eacock, F., Unger, A., Eichwald, P., Grydin, O., Hengsbach, F., Althoff, S.,
    … Guth, K. (2016). Effect of different oxide layers on the ultrasonic copper wire
    bond process. In <i>IEEE 66th Electronic Components and Technology Conference</i>
    (pp. 2111–2118). <a href="https://doi.org/10.1109/ECTC.2016.91">https://doi.org/10.1109/ECTC.2016.91</a>
  bibtex: '@inproceedings{Eacock_Unger_Eichwald_Grydin_Hengsbach_Althoff_Schaper_Guth_2016,
    title={Effect of different oxide layers on the ultrasonic copper wire bond process},
    DOI={<a href="https://doi.org/10.1109/ECTC.2016.91">10.1109/ECTC.2016.91</a>},
    booktitle={IEEE 66th Electronic Components and Technology Conference}, author={Eacock,
    Florian and Unger, Andreas and Eichwald, Paul and Grydin, Olexandr and Hengsbach,
    Florian and Althoff, Simon and Schaper, Mirko and Guth, Karsten}, year={2016},
    pages={2111–2118} }'
  chicago: Eacock, Florian, Andreas Unger, Paul Eichwald, Olexandr Grydin, Florian
    Hengsbach, Simon Althoff, Mirko Schaper, and Karsten Guth. “Effect of Different
    Oxide Layers on the Ultrasonic Copper Wire Bond Process.” In <i>IEEE 66th Electronic
    Components and Technology Conference</i>, 2111–18, 2016. <a href="https://doi.org/10.1109/ECTC.2016.91">https://doi.org/10.1109/ECTC.2016.91</a>.
  ieee: F. Eacock <i>et al.</i>, “Effect of different oxide layers on the ultrasonic
    copper wire bond process,” in <i>IEEE 66th Electronic Components and Technology
    Conference</i>, 2016, pp. 2111–2118.
  mla: Eacock, Florian, et al. “Effect of Different Oxide Layers on the Ultrasonic
    Copper Wire Bond Process.” <i>IEEE 66th Electronic Components and Technology Conference</i>,
    2016, pp. 2111–18, doi:<a href="https://doi.org/10.1109/ECTC.2016.91">10.1109/ECTC.2016.91</a>.
  short: 'F. Eacock, A. Unger, P. Eichwald, O. Grydin, F. Hengsbach, S. Althoff, M.
    Schaper, K. Guth, in: IEEE 66th Electronic Components and Technology Conference,
    2016, pp. 2111–2118.'
date_created: 2019-05-27T09:00:50Z
date_updated: 2019-09-16T10:38:59Z
department:
- _id: '151'
doi: 10.1109/ECTC.2016.91
keyword:
- Ultrasonic copper wire bonding
- Al-oxide
- Cuoxide
- oxide-free
- roughness
- morphology
language:
- iso: eng
page: 2111-2118
publication: IEEE 66th Electronic Components and Technology Conference
quality_controlled: '1'
status: public
title: Effect of different oxide layers on the ultrasonic copper wire bond process
type: conference
user_id: '55222'
year: '2016'
...
---
_id: '9868'
abstract:
- lang: eng
  text: In order to increase mechanical strength, heat dissipation and ampacity and
    to decrease failure through fatigue fracture, wedge copper wire bonding is being
    introduced as a standard interconnection method for mass production. To achieve
    the same process stability when using copper wire instead of aluminum wire a profound
    understanding of the bonding process is needed. Due to the higher hardness of
    copper compared to aluminum wire it is more difficult to approach the surfaces
    of wire and substrate to a level where van der Waals forces are able to arise
    between atoms. Also, enough friction energy referred to the total contact area
    has to be generated to activate the surfaces. Therefore, a friction model is used
    to simulate the joining process. This model calculates the resulting energy of
    partial areas in the contact surface and provides information about the adhesion
    process of each area. The focus here is on the arising of micro joints in the
    contact area depending on the location in the contact and time. To validate the
    model, different touchdown forces are used to vary the initial contact areas of
    wire and substrate. Additionally, a piezoelectric tri-axial force sensor is built
    up to identify the known phases of pre-deforming, cleaning, adhering and diffusing
    for the real bonding process to map with the model. Test substrates as DBC and
    copper plate are used to show the different formations of a wedge bond connection
    due to hardness and reaction propensity. The experiments were done by using 500
    $\mu$m copper wire and a standard V-groove tool.
author:
- first_name: Simon
  full_name: Althoff, Simon
  last_name: Althoff
- first_name: Jan
  full_name: Neuhaus, Jan
  last_name: Neuhaus
- first_name: Tobias
  full_name: Hemsel, Tobias
  id: '210'
  last_name: Hemsel
- first_name: Walter
  full_name: Sextro, Walter
  id: '21220'
  last_name: Sextro
citation:
  ama: 'Althoff S, Neuhaus J, Hemsel T, Sextro W. Improving the bond quality of copper
    wire bonds using a friction model approach. In: <i>Electronic Components and Technology
    Conference (ECTC), 2014 IEEE 64th</i>. ; 2014:1549-1555. doi:<a href="https://doi.org/10.1109/ECTC.2014.6897500">10.1109/ECTC.2014.6897500</a>'
  apa: Althoff, S., Neuhaus, J., Hemsel, T., &#38; Sextro, W. (2014). Improving the
    bond quality of copper wire bonds using a friction model approach. In <i>Electronic
    Components and Technology Conference (ECTC), 2014 IEEE 64th</i> (pp. 1549–1555).
    <a href="https://doi.org/10.1109/ECTC.2014.6897500">https://doi.org/10.1109/ECTC.2014.6897500</a>
  bibtex: '@inproceedings{Althoff_Neuhaus_Hemsel_Sextro_2014, title={Improving the
    bond quality of copper wire bonds using a friction model approach}, DOI={<a href="https://doi.org/10.1109/ECTC.2014.6897500">10.1109/ECTC.2014.6897500</a>},
    booktitle={Electronic Components and Technology Conference (ECTC), 2014 IEEE 64th},
    author={Althoff, Simon and Neuhaus, Jan and Hemsel, Tobias and Sextro, Walter},
    year={2014}, pages={1549–1555} }'
  chicago: Althoff, Simon, Jan Neuhaus, Tobias Hemsel, and Walter Sextro. “Improving
    the Bond Quality of Copper Wire Bonds Using a Friction Model Approach.” In <i>Electronic
    Components and Technology Conference (ECTC), 2014 IEEE 64th</i>, 1549–55, 2014.
    <a href="https://doi.org/10.1109/ECTC.2014.6897500">https://doi.org/10.1109/ECTC.2014.6897500</a>.
  ieee: S. Althoff, J. Neuhaus, T. Hemsel, and W. Sextro, “Improving the bond quality
    of copper wire bonds using a friction model approach,” in <i>Electronic Components
    and Technology Conference (ECTC), 2014 IEEE 64th</i>, 2014, pp. 1549–1555.
  mla: Althoff, Simon, et al. “Improving the Bond Quality of Copper Wire Bonds Using
    a Friction Model Approach.” <i>Electronic Components and Technology Conference
    (ECTC), 2014 IEEE 64th</i>, 2014, pp. 1549–55, doi:<a href="https://doi.org/10.1109/ECTC.2014.6897500">10.1109/ECTC.2014.6897500</a>.
  short: 'S. Althoff, J. Neuhaus, T. Hemsel, W. Sextro, in: Electronic Components
    and Technology Conference (ECTC), 2014 IEEE 64th, 2014, pp. 1549–1555.'
date_created: 2019-05-20T12:11:44Z
date_updated: 2019-09-16T10:57:58Z
department:
- _id: '151'
doi: 10.1109/ECTC.2014.6897500
keyword:
- adhesion
- circuit reliability
- deformation
- diffusion
- fatigue cracks
- friction
- interconnections
- lead bonding
- van der Waals forces
- Cu
- adhering process
- adhesion process
- ampacity improvement
- bond quality improvement
- cleaning process
- diffusing process
- fatigue fracture failure
- friction energy
- friction model
- heat dissipation
- mechanical strength
- piezoelectric triaxial force sensor
- predeforming process
- size 500 mum
- total contact area
- van der Waals forces
- wedge copper wire bonding
- Bonding
- Copper
- Finite element analysis
- Force
- Friction
- Substrates
- Wires
language:
- iso: eng
page: 1549-1555
publication: Electronic Components and Technology Conference (ECTC), 2014 IEEE 64th
quality_controlled: '1'
status: public
title: Improving the bond quality of copper wire bonds using a friction model approach
type: conference
user_id: '55222'
year: '2014'
...
---
_id: '9895'
abstract:
- lang: eng
  text: Power semiconductor modules are used to control and switch high electrical
    currents and voltages. Within the power module package wire bonding is used as
    an interconnection technology. In recent years, aluminum wire has been used preferably,
    but an ever-growing market of powerful and efficient power modules requires a
    material with better mechanical and electrical properties. For this reason, a
    technology change from aluminum to copper is indispensable. However, the copper
    wire bonding process reacts more sensitive to parameter changes. This makes manufacturing
    reliable copper bond connections a challenging task. The aim of the BMBF funded
    project Itsowl-InCuB is the development of self-optimizing techniques to enable
    the reliable production of copper bond connections under varying conditions. A
    model of the process is essential to achieve this aim. This model needs to include
    the dynamic elasto-plastic deformation, the ultrasonic softening effect and the
    proceeding adhesion between wire and substrate. This paper focusses on the pre-deformation
    process. In the touchdown phase, the wire is pressed into the V-groove of the
    tool and a small initial contact area between wire and substrate arise. The local
    characteristics of the material change abruptly because of the cold forming. Consequently,
    the pre-deformation has a strong effect on the joining process. In [1], a pre-cleaning
    effect during the touchdown process of aluminum wires by cracking of oxide layers
    was presented. These interactions of the process parameters are still largely
    unknown for copper. In a first step, this paper validates the importance of modeling
    the pre-deformation by showing its impact on the wire deformation characteristic
    experimentally. Creating cross-section views of pre-deformed copper wires has
    shown a low deformation degree compared to aluminum. By using a digital microscope
    and a scanning confocal microscope an analysis about the contact areas and penetration
    depths after touchdown has been made. Additionally, it has to be taken into account
    that the dynamical touchdown force depends on the touchdown speed and the touchdown
    force set in the bonding machine. In order to measure the overshoot in the force
    signals, a strain gauge sensor has been used. Subsequently, the affecting factors
    have been interpreted independently Furthermore, the material properties of copper
    wire have been investigated with tensile tests and hardness measurements. In a
    second step, the paper presents finite element models of the touchdown process
    for source and destination bonds. These models take the measured overshoot in
    the touchdown forces into account. A multi-linear, isotropic material model has
    been selected to map the material properties of the copper. A validation of the
    model with the experimental determined contact areas, normal pressures and penetration
    depths reveals the high model quality. Thus, the simulation is able to calculate
    and visualize the three dimensional pre-deformation with an integrated material
    parameter of the wire if the touchdown parameters of the bonding machine are known.
    Based on the calculated deformation degrees of wire and substrate, it is probably
    possible to investigate the effect of the pre-deformation on the pre-cleaning
    phase in the copper wire bonding.
author:
- first_name: Andreas
  full_name: Unger, Andreas
  last_name: Unger
- first_name: Walter
  full_name: Sextro, Walter
  id: '21220'
  last_name: Sextro
- first_name: Simon
  full_name: Althoff, Simon
  last_name: Althoff
- first_name: Paul
  full_name: Eichwald, Paul
  last_name: Eichwald
- first_name: Tobias
  full_name: Meyer, Tobias
  last_name: Meyer
- first_name: Florian
  full_name: Eacock, Florian
  last_name: Eacock
- first_name: Michael
  full_name: Brökelmann, Michael
  last_name: Brökelmann
citation:
  ama: 'Unger A, Sextro W, Althoff S, et al. Experimental and Numerical Simulation
    Study of Pre-Deformed Heavy Copper Wire Wedge Bonds. In: <i>Proceedings of the
    47th International Symposium on Microelectronics (IMAPS)</i>. San Diego, CA, US;
    2014:289-294.'
  apa: Unger, A., Sextro, W., Althoff, S., Eichwald, P., Meyer, T., Eacock, F., &#38;
    Brökelmann, M. (2014). Experimental and Numerical Simulation Study of Pre-Deformed
    Heavy Copper Wire Wedge Bonds. In <i>Proceedings of the 47th International Symposium
    on Microelectronics (IMAPS)</i> (pp. 289–294). San Diego, CA, US.
  bibtex: '@inproceedings{Unger_Sextro_Althoff_Eichwald_Meyer_Eacock_Brökelmann_2014,
    place={San Diego, CA, US}, title={Experimental and Numerical Simulation Study
    of Pre-Deformed Heavy Copper Wire Wedge Bonds}, booktitle={Proceedings of the
    47th International Symposium on Microelectronics (IMAPS)}, author={Unger, Andreas
    and Sextro, Walter and Althoff, Simon and Eichwald, Paul and Meyer, Tobias and
    Eacock, Florian and Brökelmann, Michael}, year={2014}, pages={289–294} }'
  chicago: Unger, Andreas, Walter Sextro, Simon Althoff, Paul Eichwald, Tobias Meyer,
    Florian Eacock, and Michael Brökelmann. “Experimental and Numerical Simulation
    Study of Pre-Deformed Heavy Copper Wire Wedge Bonds.” In <i>Proceedings of the
    47th International Symposium on Microelectronics (IMAPS)</i>, 289–94. San Diego,
    CA, US, 2014.
  ieee: A. Unger <i>et al.</i>, “Experimental and Numerical Simulation Study of Pre-Deformed
    Heavy Copper Wire Wedge Bonds,” in <i>Proceedings of the 47th International Symposium
    on Microelectronics (IMAPS)</i>, 2014, pp. 289–294.
  mla: Unger, Andreas, et al. “Experimental and Numerical Simulation Study of Pre-Deformed
    Heavy Copper Wire Wedge Bonds.” <i>Proceedings of the 47th International Symposium
    on Microelectronics (IMAPS)</i>, 2014, pp. 289–94.
  short: 'A. Unger, W. Sextro, S. Althoff, P. Eichwald, T. Meyer, F. Eacock, M. Brökelmann,
    in: Proceedings of the 47th International Symposium on Microelectronics (IMAPS),
    San Diego, CA, US, 2014, pp. 289–294.'
date_created: 2019-05-20T13:35:09Z
date_updated: 2020-05-07T05:33:47Z
department:
- _id: '151'
keyword:
- pre-deformation
- copper wire bonding
- finite element model
language:
- iso: eng
page: 289-294
place: San Diego, CA, US
project:
- _id: '92'
  grant_number: 02 PQ2210
  name: Intelligente Herstellung zuverlässiger Kupferbondverbindungen
publication: Proceedings of the 47th International Symposium on Microelectronics (IMAPS)
status: public
title: Experimental and Numerical Simulation Study of Pre-Deformed Heavy Copper Wire
  Wedge Bonds
type: conference
user_id: '210'
year: '2014'
...