Study on the electrical breakdown failure mode transition of TSV-RDL

Abstract

This study investigates the electrical breakdown failure modes and mechanisms of TSV-RDL (Through-Silicon Via with Redistribution Layer) structures through experiments and finite element simulation analysis. By employing a Taguchi method-based finite element simulation, the impact of structural parameters on the electrical breakdown failure modes of TSV-RDLs has been explored. The study reveals two electrically induced breakdown failure modes for TSV-RDLs. One case involves failures occurring at the RDL_pad/SiO2 interface, while the other involves failures within the SiO2 layer along the TSV sidewall interface. The design of TSV-RDLs can influence the distribution of electric field strength and subsequently lead to different electrical breakdown failure modes. In the case of double-blind solid TSV-RDLs, double-through solid TSV-RDLs, and double-blind hollow TSV-RDLs, the pad pitch is identified as a crucial parameter that affects their failure modes. As the pad pitch increases, the location of electrical breakdown failure shifts from the RDL_pad/SiO2 interface to the SiO2 layer along the TSV sidewall interface. Conversely, for the double-through hollow TSV-RDL structure, the structural parameters of TSV, including TSV height, TSV pitch, and SiO2 layer thickness, are the principal factors influencing its failure modes. As these parameters decrease, the position of electrical breakdown failure transitions from the RDL_pad/SiO2 interface to the SiO2 layer along the TSV interface.