Modeling and Characterization of Through-Silicon-Vias (TSVs) in Radio Frequency Regime in an Active Interposer Technology

In this paper, modeling and characterization of TSVs in radio frequency (RF) regime in an "active interposer" technology is presented. In this technology, a top die is stacked on top of a base die and TSV is employed as an interconnect that carries signals and power from off-chip sources to the base die and the top die. Modeling of the TSVs carrying signal for high frequency applications depends heavily on the design of the test structures and the de-embedding method. In this study, transmission lines (TLs) are used as the redistribution layer (RDL) test structure to characterize the electromagnetic properties of the TSV. TLs with different lengths are used which enables the application of different de-embedding methods for TSVs’ lumped model extraction. Three different de-embedding methods are introduced and applied to extract the RF properties of the TSVs, and a comparison of their accuracy is discussed. Full-wave electromagnetic (EM) simulations are performed comparing the RF performance of the devices-under-test and a correlation of simulations to extracted silicon data is made. As the TSVs are not fully symmetrical in this process, the frequency band where the accurate RF data is valid is highlighted. A wide-band lumped-element RLC model for the TSVs is generated and how the individual components of the model vary with respect to the number of employed TSVs as well as the architecture where they are placed with respect to each other are studied.