Title page for etd-0722116-130209


[Back to Results | New Search]

URN etd-0722116-130209
Author Ming-Chi Ho
Author's Email Address chicken_ho@hotmail.com
Statistics This thesis had been viewed 5366 times. Download 0 times.
Department Materials and Optoelectronic Science
Year 2015
Semester 2
Degree Ph.D.
Type of Document
Language zh-TW.Big5 Chinese
Title Intermetallic Phases Formation Mechanism of Cu Wire Bonding and Phase Equilibrium Study of Ag Wire Bonding in the Electronic Packaging
Date of Defense 2016-07-26
Page Count 163
Keyword
  • Ag-Al-Au phase diagram
  • Ag wire bonding
  • Cu wire bonding
  • IMC
  • IC package
  • Abstract For lower cost considerations, copper wire bonding has been applied in IC packaging in recent years. In this study, the intermetallics(IMCs) formed, growth and crack development were examined to evaluate the reliability of several copper wires with/ without wire surface coatings.In this study, the reliability tests include HTST, PCT, and TCT. The wire types are the 0.7 mil 4N copper wires, the Palladium coated-Copper (Pd-Cu) wires, and Au-Pd-plated copper wires. And there are three substrate types with the aluminum pad thickness of 1.6/2.8/4 micrometer. For the HTST test samples, two aging temperatures, 175℃and 205℃ were applied and the aging periods from 150 hrs to 2000 hrs. The microstructure of micro joints are cross-sectioned and examined under an electron microprobe to verified the formed intermetallic phases for the samples tested in various aging periods. The samples under PCT and TCT tests are examined for the corrosion and crack formation behavior. The formation of IMCs, Cu9Al4, CuAl and CuAl2, which are main compounds formed in copper wire bonding micro joints. The Al-rich phase (CuAl2) has high priority, and the second phase(Cu9Al4) appear on the interface near the copper wire side. After long period aging, the Cu-rich phase(Cu9Al4) expected to form when Al pad be consumed. However, in the thicker Al pad cases, the Cu9Al4 phase will be replace by the first phase(CuAl2) finally. The results also show that, the kirkendall voids accumulate and form cracks in the bonding micro joint, and therefore make the micro joint fail. The intermetallic formation sequences of different wire types are shown for a comparison.The second part of study is about Ag wire bonding process. Ag wire has good electric conductivity, thermal conductivity, high current withstand capacity, and easy to store. However, compared to Au-Al wire bonding system, it is not enough to understand Ag-Al-Au phase diagram and the intermetallic formation of Ag-alloy wire bonding. This study of Ag wire can provide more information about diffusion paths and phase identification of Ag-Al-Au ternary system in the lower temperature.
    Advisory Committee
  • P.W. Kao - chair
  • New-Jin Ho - co-chair
  • Cho-Liang Chung - co-chair
  • Yung-Chung Chen - co-chair
  • Ker-Chang Hsieh - advisor
  • Files
  • etd-0722116-130209.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2016-08-22

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have more questions or technical problems, please contact eThesys