---
_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'
...