Measurements of interfacial strengths in underfilled flip-chip electronic packages using Wedge Delamination Method (WDM)

In this work, a new wedge delamination technique for measurement of interfacial fracture strength is presented. This method can be implemented to assess the interfacial fracture behavior of underfill and silicon in flip-chip packages. Our method offers substantial advantages over traditional interfacial test methods which can be difficult to implement on brittle materials like silicon die. The efficacy of our method for interfacial strength measurements on multiple underfill-silicon interfaces will be shown in this work. A numerical framework for crack kinking at the silicon-underfill interface will also be presented. And finally, results from WDM experiments conducted at room temperature and corresponding numerical analysis will be used to compare the relative fracture strength between underfill and silicon at the flat-face and sidewall of a silicon die.