High-Frequency Transmission Characteristic Analysis of TSV-RDL Interconnects
Yiming Zhang, Wenchao Tian, Hongyue Wang, Lei Wang, Zhili Yang, Weiheng Shao, Ze‐Jian Chen, Bin Zhou
Abstract
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 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLGC</i> parameters on transmission loss from DC to high frequency up to 40 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GHz</i> , which exhibits a good correlation with the measured and de-embedded transmission characteristics results. It found that the crucial effect of oxide-layer capacitance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>ox</sub></i> ) in the low-frequency range (from 100 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">kHz</i> to 1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GHz</i> ), while conductance and capacitance in silicon ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C<sub>si</sub></i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G<sub>si</sub></i> ) have a vital impact in the mid-frequency range (from 1 GHz to 10 GHz). Additionally, the inductance ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> ) component is found to have a dominant impact on the transmission loss in the high-frequency range (from 10 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GHz</i> to 40 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GHz</i> ).