Thermomechanical modeling of back-end-of-the-line 3D interconnects

Three-dimensional (3D) integrated circuits (ICs) offer considerable advantages over traditional 2D IC designs by offering increased signal speeds and lower operation power, and by combining multiple technology functions in a low-volume, stacked design. The design complexity of 3D ICs introduces an increased sensitivity of operation and reliability due to the thermomechanical interactions among their multilevel components. Therefore, physical modeling has become a critical task in the design phase of 3D ICs to manage and reduce these sensitivities, and to increase yield and reliability. In this paper, we develop and employ a high-fidelity, 3D finite element modeling framework to examine the thermomechanical response of 3D IC interconnects. We demonstrate attributes of our framework on a back-end-of-the-line via chain. First, we generate geometry using process definitions, develop a parameterized mesh, and identify material parameters from characterization experiments. Then, using advanced, massively parallel computational resources, we simulate fabrication steps to approximate the stresses and deformations experienced by the microstructure as a result of processing temperatures. Ultimately, our modeling approach provides a capability to assess the thermomechanical response of 3D IC components and provides a basis for designing structures robust to fabrication and processing variations.