Title page for etd-0720109-184258


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URN etd-0720109-184258
Author Hsin-Chih Shih
Author's Email Address No Public.
Statistics This thesis had been viewed 5334 times. Download 3196 times.
Department Mechanical and Electro-Mechanical Engineering
Year 2008
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Orientation effects on Cu wire bonding by finite element method
Date of Defense 2009-06-18
Page Count 98
Keyword
  • Molecular dynamics
  • Finite element method
  • Copper wire bonding
  • Abstract Ball bonding with gold wire has been the preferred choice to connect semiconductor chip and a lead frame. Recently, copper wires have been increasingly used to replace gold wires because of the rising price of gold. However, copper is harder than gold and has the tendency to induce the damage of bond pad or other underlying layers. Herein, Al pad material has to be changed from bulk to single crystal with (100) surface orientation in order to improve bonding reliability.
    Firstly, finite element method was adopted to simulate 3D wire bonding. Also, from the impact of gold wire bonding, the stress concentration was found on pad and underlying layers due to the higher elastic modulus of bulk Al. During copper ball impact, there is not only the serious stress concentration at pad, but also a pad splash due to the insufficient strength of bulk Al, even though bulk Al has a lower elastic modulus.
    Secondly, material properties of Al(100) were obtained by uniaxial tensile tests at constant speed. With molecular dynamics method, the incorporated result showed that Al(100) has the lower elastic modulus and higher yield strength than those of bulk material.
    Finally, single crystal Al(100) was used, instead of bulk material, to carry out copper ball impact process by using multi-scale simulation. Al(100) material is able to transform impact energy into the resilience of strain energy effectively owing to its high yield stress and low elastic modulus. Results show that the application of Al(100) material reduces the effects of stress concentration and pad “splashing” successfully during copper ball impact process.
    Advisory Committee
  • J. C. Huang - chair
  • Yi-Shao Lai - co-chair
  • Ming Chen - co-chair
  • Ming-Hwa R. Jen - advisor
  • Files
  • etd-0720109-184258.pdf
  • indicate access worldwide
    Date of Submission 2009-07-20

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