High-Frequency Transmission Characteristic Analysis of TSV-RDL Interconnects

With the development of Through Silicon Vias (TSV) and Re-distributed 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 deteriorates at high frequencies. Designs without consideration of the high-frequency effects of TSV and RDL will seriously affect signal integrity and cause significant performance degradation on high-speed channels. In this paper, the frequency-dependent transmission characteristics of the TSV and RDL are investigated. Three test vehicles were designed for frequency-domain measurement and verification. The TRL de-embedding 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 RLGC parameters on transmission loss from DC to high frequency up to 40 GHz , which exhibits a good correlation with the measured and de-embedded transmission characteristics results. It found that the crucial effect of oxide-layer capacitance ( C_ox ) in the low-frequency range (from 100 kHz to 1 GHz ), while conductance and capacitance in silicon ( C_si and G_si ) have a vital impact in the mid-frequency range (from 1 GHz to 10 GHz). Additionally, the inductance ( L ) component is found to have a dominant impact on the transmission loss in the high-frequency range (from 10 GHz to 40 GHz ).