Rohit Gandhi1, Nikhitha Poornabodha1, Pallavi Jithendrriyan1, Pranav Srinivasan2, Aniket Bharamgonda2, Christopher Bailey1and Abhijit Dasgupta2
1Arizona State University, Tempe, AZ, United States
2CALCE, University of Maryland, College Park, MD, USA
For more information about this article and related research, please contact Prof. Abhijit Dasgupta.
Abstract:
As advanced packaging demands higher interconnect density, Redistribution Layer (RDL) technologies must accommodate progressively smaller line widths and tighter spacing. However, this scaling intensifies reliability challenges, making ultrafine RDLs highly vulnerable to progressive crack growth and delamination. Currently, macroscopic experimental methods like the Double Cantilever Beam (DCB) test are employed to measure fracture energy and extract parameters for Cohesive Zone Modeling (CZM). Yet, as RDLs transition to sub-micron regimes, adapting classical fracture-mechanics tests becomes challenging because the target interface is often buried deep within a multi-material stack, making it difficult to control the crack path and isolate specific fracture planes. To overcome these metrology limitations, this paper presents a Molecular Dynamics (MD) approach to extract intrinsic interfacial traction-separation behavior at the nanoscale. Because MD and macroscopic experiments operate at very different scales, the atomistic results are transformed through scaling coefficients to produce CZM parameters that are MD-informed and experimentally consistent in energy. Ultimately, this multiscale framework demonstrates the importance of accurately assessing package reliability by bridging nanoscale interfacial behavior with macroscale predictive design-for-reliability in next-generation RDL stacks
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