In this paper, we present an overview of our current research focus in developing non-destructive metrology for monitoring reliability issues in 3D- integrated electronic systems. We introduce a suite of non-destructive metrologies that can serve as early warning monitors for reliability issues. These Broadband Dielectric Spectroscopic (BDS) techniques are based on the application of high frequency microwaves (up to 40 GHz) to devices under various external stress, to probe impedance changes due to material and structural changes in integrated circuits. We illustrate the capabilities of the techniques with four case studies of potential reliability issues in 3D-IC interconnects.