Multi-port characterization of vias using indirect contact probing method

In this paper, an indirect contact probing method is presented to characterize vertical interconnects. By adopting a dielectric contactor, the indirect contact probing protects interconnects from the direct-contact of probe tips. Also, the dielectric contactor improves the measurement sensitivity. Moreover, providing the constant gap of the contactor omits additional control and sensor electronics. The procedure for the proposed method starts with one-port calibration enabling the dielectric contactor between the probe pads and the device-under-tests (DUT) characterized. Next, the indirect-contact measurement on the DUT is conducted. The DUT is finally extracted from de-embedding the dielectric contactor layer. We extend the proposed method from a single pair of vias to multiple vias, and multi-port network extraction to obtain coupling between vias is also carried out. In simulations the proposed method for a single pair of vias characterizes the vias from 0.8 GHz to 30 GHz, and for multi-via testing and multi-port extraction from 0.8 GHz to around 25 GHz. We have verified all via defects can be successfully identified from the indirect contact probing method.