Numerical and experimental exploration of thermal isolation in 3D systems using air gap and mechanically flexible interconnects

This paper proposes a thermal isolation technology using air gap and mechanically flexible interconnects (MFIs) for heterogeneous 3-D integration. Thermal modeling shows that the proposed architecture achieves a temperature reduction of approximately 40.0% in the low-power tier compared to conventional approaches using microbumps and underfill. To demonstrate the technology, a two-tier testbed is fabricated, assembled and tested. The experimental results of test cases show an average temperature reduction of approximately 30.0% in the low-power tier.