Compliance analysis of multi-path fan-shaped interconnects

Compliant microelectronic interconnects are potential replacements for solder balls which accommodate this differential displacement by mechanically decoupling the die from the substrate or the substrate from the board and aim to improve overall reliability and life of the microelectronic system. Multi-path, fan-shaped compliant interconnect is being pursued at Georgia Tech as an alternate die-to-substrate or substrate-to-board interconnect. This multi-path fan-shaped interconnect has arcuate structures as well as vertical posts to provide in-plane and out-of-plane compliance, respectively. In this paper, we present the compliance values for the proposed interconnects using analytical formulations and finite-element simulations and compare these values using experimental data. The analytical formulations can be used for optimization of the geometry, because we can know the contribution of the parameters to the compliant values from the potential energy terms. Finite-element simulations can take elastic–plastic into consideration, while the analytical formulation cannot. They also help to validate our results because they were developed independently. It is seen that the scaled-up polymer interconnects will have a compliance of 0.1–0.15 mm/N in the out-of-plane direction and 0.05–0.15 mm/N in the in-plane directions. Also, it is seen that the results from finite-element simulations using 3D solid elements as well as beam elements agree against each other, and also against analytical models and experimental measurements.