High-Frequency Transmission Characteristic Analysis of TSV-RDL Interconnects

With the development of through-silicon vias (TSVs) and redistributed layer (RDL) manufacturing technology, it is applied to high-frequency and high-speed data path interconnection. Compared with traditional direct current (dc) supply, it pays more attention to transmission performance deteriorating at high frequencies. Designs without consideration of the high-frequency effects of TSV and RDL will seriously affect signal integrity (SI) and cause significant performance degradation on high-speed channels. In this article, the frequency-dependent transmission characteristics of the TSV and RDL are investigated. Three test vehicles were designed for frequency-domain measurement and verification. The through–reflect–line (TRL) deembedding process is introduced to obtain the accurate
${S}$
-parameters of the TSV-RDL coplanar waveguide (CPW). Accordingly, an equivalent-circuit model is constructed to study the impact of resistance, inductance, conductance, and capacitance (RLGC) parameters on transmission loss from dc to high frequency up to 40 GHz, which exhibits a good correlation with the measured and deembedded transmission characteristics results. It found that the crucial effect of oxide-layer capacitance (
${C}_{{\text {ox}}}$
) in the low-frequency range (from 100 kHz to 1 GHz), while conductance and capacitance in silicon (
${C}_{{\text {si}}}$
and
${G}_{{\text {si}}}$
) have a vital impact on the mid-frequency range (from 1 to 10 GHz). In addition, the inductance (
${L}$
) component is found to have a dominant impact on the transmission loss in the high-frequency range (from 10 to 40 GHz).