Induced thermo-mechanical reliability of copper-filled TSV interposer by transient selective annealing technology
Abstract Managing the stability of related processes in the integrated manufacturing of three-dimensional integrated circuits (3D-ICs) remains unresolved, especially with regard to the thermo-mechanical behavior of copper filled through silicon via (TSV) interposer during annealing. In this work, transient annealing is successfully applied on the filled copper using only one form of selective heating technology. To address the integration problem, transient thermo-structural coupling analysis using a nonlinear finite element simulation is proposed. Compared with the experimental data, the proposed simulation is found to be highly reliable. Analytical results show that temperature decreases from the top surface of the TSV to other regions within a silicon-based TSV interposer. Stress-induced fracture is common among bonded films, thereby worsening the subsequent mechanical reliability of 3D-IC devices. Moreover, the extent of keep-out zone induced by residual stress of Cu-filled TSV is also defined through the simulation-based mobility gain of nano-scaled devices. In accordance with the results of this investigation, an improvement can be obtained by optimizing the fabrication parameters during annealing. The proposed technology provides a high throughput and reliable processes in TSV manufacturing.