Microsystem Technologies

, Volume 15, Issue 1, pp 83–88 | Cite as

Application of interfacial fracture mechanics approach for obtaining design rules for flip chip interconnections

  • M. Dreßler
  • K-F. Becker
  • B. Wunderle
  • J. Auersperg
  • H. Reichl
Technical Paper

Abstract

The reliability of an electronic package can be described by a physics-of-failure approach. Crack initiation and propagation in the bulk material and interface leads to catastrophic mechanical and finally to electrical failure. Therefore, bulk and interfacial fracture mechanics is a suitable method to describe the reliability of an electronic package. As package, a stud bump bonding flip chip interconnection on a thermoplastic substrate material [liquid crystal polymer (LCP)] is studied. The paper focuses on the description of the interfacial cracking between the underfill and the LCP. This is used to obtain design rules for flip chip interconnection on LCP by means of finite element analysis. Geometry design parameters—fillet shape, chip and substrate sizes—are studied. Moreover, the influence of material properties of the substrate and underfill are investigated. The impacts of the parameters are evaluated by analyzing the energy release rate (ERR) and mode-mixity in the interface. For determination of the critical ERR as function of the mode-mixity, a modified button shear test is utilized. The button, made out of underfill, is cured on the LCP substrate. A pre-delamination is established using a Teflon strip. The critical ERR for different mode-mixities is obtained by varying the shearing height of the button test. Additional, the influence of oxygen plasma treatment of the LCP substrate on the interfacial cracking is taken into account. In the investigation, design rules for increasing the reliability of flip chip interconnections are obtained. Moreover, a modified button-test is applied to obtain critical energy releases rates for different mode-mixities for the interface underfill/LCP. These results are used to optimize the geometry and materials of flip chip interconnections for automotive sensor applications in respect to delamination risk between substrate and underfill.

References

  1. Auersperg J, Kieselstein E, Schubert A, Michel B (2002) Delamination risk evalulation for plastic packages based on mixed mode fracture mechanics approaches. J Electron Packag 124(4):318–322CrossRefGoogle Scholar
  2. Becker K-F, Kilic N, Braun T, Koch M, Bader V, Aschenbrenner R et al (2003) New insights in underfill flow and flip chip reliability. APEX Conference, AnaheimGoogle Scholar
  3. Dreßler M, Rohde H, Liebing G, Becker K-F, Wunderle B, Reichl H (2006a) Influence of assembly process, material properties and geometry on the reliability of flip chip interconnections on MID for automotive applications. 7th international congress molded interconnect devices, 27–28 September 2006, Fuerth, GermanyGoogle Scholar
  4. Dreßler M, Rohde H, Liebing G, Auersperg J, Becker K-F, Wunderle B, Reichl H (2006b) Identifying the reliability affecting parameters of SBB flip chip interconnections for automotive applications. 1st Electronics systemintegration technology conference, Dresden, 41–50Google Scholar
  5. Krueger R (2002). The virtual crack closure technique: history, approach and applications. NASA/CR-2002-211628, ICASE Report No. 2002-10Google Scholar
  6. Nied HF (2003) Mechanics of interface fracture with applications in electronic packaging. IEEE Trans Device Mater Reliab 3(4)Google Scholar
  7. Rybicki EF, Kanninen MF (1997) A finite element calculation of stress intensity factors by a modified crack closure integral. Eng Fract Mech 9:931–938CrossRefGoogle Scholar
  8. Schledjewski R, Friedrich K (1992) Tensile properties of filled liquid-crystal polymer systems. J Mater Sci Lett 11(12):840–842CrossRefGoogle Scholar
  9. Sham L, Lam M, Kim J-K (2001) Adhesion characteristics of underfill material with various package components after plasma and UV/ozone treatment. Electronic Materials and Packaging, 2001 (EMAP 2001), Feju Island, South Korea, pp 208–215Google Scholar
  10. Tay AAO, Phang JS, Wong EH, Ranjan R (2003) A modified button-shear method for measuring fracture toughness of polymer-metal interfaces in IC packages. Electronic components and technology conference, 27–30 May 2003, New Orleans, Louisiana, USA, pp 1165–1169Google Scholar
  11. Tong Q, Ma B, Xiao A, Savoca A, Luo S, Wong CP (2002) Fundamental adhesion issues for advanced flip chip packaging. Electronic components and technology conference, 28–31 May 2002, San Diego, California, USAGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • M. Dreßler
    • 1
  • K-F. Becker
    • 2
  • B. Wunderle
    • 2
  • J. Auersperg
    • 2
  • H. Reichl
    • 3
  1. 1.Robert Bosch GmbHCorporate Sector Research and Advance EngineeringWaiblingenGermany
  2. 2.Fraunhofer Institute for Reliability and Microintegration (IZM)BerlinGermany
  3. 3.Research Center Microperipheric TechnologiesBerlin Technical UniversityBerlinGermany

Personalised recommendations