Microstructure and Mechanical Reliability Issues of TSV

Abstract

The copper pumping problem exemplifies the complex reliability issues still to be resolved for TSV structures. From a materials science perspective the reliability issues presented by TSVs are linked to manufacturing processes and the resultant microstructure formed. Routine finite-element based reliability studies that treat the TSV filler as an isotropic and homogeneous material are not capable of providing a sufficiently thorough explanation of the observed copper extrusion/intrusion behavior. Rather, the material behavior and properties at multiple scales are required as the input data for effective reliability analysis of three- dimensional TSV stacked ICs. Such 3-D ICs also push the scale of materials to a limit where the anisotropy of material properties, recovery, recrystallization and time-dependent phase morphological evolution further complicate reliability issues. This chapter reviews both experimental and modeling approaches that address the microstructural and reliability issues of TSVs. Crystal plasticity based finite element analysis (FEA) and phase field crystal method with an inherently multiscale nature are identified as promising modeling techniques to enable atomistically-informed reliability analysis of TSVs.