Kein Folientitel

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Materials and Manufacturing in Electronics Prof.
Dr.-Ing. Jürgen Villain University of Applied
Sciences Augsburg, Germany Department of
Electrical Engineering
COST 531 Meeting 14.1.2003 Berlin
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Lectures and Team

• Lectures
• Materials Science for Engineers
• Manufacturing in Electronics
• Packaging
• Design and Strength of Materials

• Team in the Lab
• Dipl.-Ing. T. Qasim (material science)
• Dipl.-Ing. Ch. Weippert (crystallography)
• Dipl.-Ing. (FH) A. Svetly (mechanical
  engineering)
• J. Pahl (material test)
• E. Hundt (measuring technique)
• Students, candidate for a doctors degree

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• Topics of Research
• Influence of structure on the mechanical
  behaviour of metals
• Determination of mechanical properties of small
  specimens depending on temperature and strain
  rate
• Size effect on mechanical properties of metals
  in electronics
• Vapour-phase soldering of lead-free solder
  materials
• Creep behaviour of solder materials
• Formation of intermediate phases in small solder
  volumes

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Equipment of the
Lab Macro and micro tension test machines (0.5 N
500 N, -55 C/250 C) Pull- and
Shear-Test Creep Test (RT/200 C) Laser
extensometer Special clamping jaws for small
specimens Micro-hardness tester SEM with EDX
(tension and creep tests inside possible) X-ray
fluorescent analysis Thermal shock Vapour-Phase
soldering Wetting tester Ovens
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Tools for small specimens
Special clamping jaws for small Cu-Foils (10 µm
- 250 µm)
Tensile module for small specimens (part of SEM)
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Determination of mechanical properties of small
specimens depending on temperature and strain
rate
Elongation at rupture of Sn43Bi57 for different
temperatures and strain rates
Tensile strength of Sn43Bi57 for different
temperatures and strain rates
Material parameters describing exactly the
material behaviour of electronic devices under
working conditions are necessary for
thermo-mechanical simulations.
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Size Effect on Mechanical Properties of Copper
Foils
The smaller the tested volume the lower the
ductility !
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Manufacturing and Reliability of Lead-Free-Solders
Topics Manufacturing parameters, shear and
tensile strength, creep- behaviour, migration,
intermediate compounds Solder materials
Sn91Zn9, Sn43Bi57, Sn96.5Ag3.5,
Sn93.5Ag3.8Cu0.7Bi2(4)
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Phase Formation in Small Solder Volumes
(intermediate phases)
Sn43Bi57, device Sn, Pad Cu/Ni/Au
Sn91Zn9, device Sn, Pad Cu/Ni/Au
Small solder volumes are out of thermodynamic
equilibrium and consist mainly of intermediate
phases (3 5 elements) with almost completely
unknown material properties.
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Creep behaviour of solder materials
60Sn40Pb, Qm 0.73 eV
The creep behaviour of solder materials at
high homologous temperatures can be described
using a viscoplastic equation. e(t,T,s)so J(t)
as aT
43Sn57Bi, Qm 0.76 eV
91Sn9Zn, Qm 1.01 eV
96.5Sn3.5Ag, Qm 0.87 eV
Lowest homologoues temperature, highest
homologoues stress
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Comparison of Activation Energies and
Time-Temperature Shift-Factor
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Size Effect on Creep Behaviour of a Solder
Material
Sn60Pb40, stress 5 N/mm2, same structure, same
strain rate. The smaller the tested volume the
lower the creep resistance.
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Further investigations Analysis of metallic and
intermediate phases of small solder
volumes Determination of the mechanical
behaviour of eutectic and non eutectic solder
materials with regard to structure and tested
volume under experimental and numerical view