The 2.5D interposer becomes a crucial solution to realize grand bandwidth of HBM for the increasing data requirement of high performance computing (HPC) and Artificial Intelligence (AI) applications. To overcome high speed switching bottleneck caused by the large resistive and capacitive characteristics of interposer, design methods to achieve an optimized performance in a limited routing area are proposed. Unlike the conventional single through silicon via (TSV), considering the reliability, multiple TSV are used as the robust 3D interconnects for each signal path. An equivalent model to accurately describe the electrical characteristics of the multiple TSVs, and a configuration pattern strategy of TSV to mitigate crosstalk are also proposed.

This paper proposes a design flow for channel design by a fast hierarchical optimization method based on Channel Operating Margin (COM). Unlike the common design of experiment (DOE), the method performs the design by a hierarchical flow in the level of electrical characteristic while not the usual horizontal structure of physical parameters. It significantly reduces the number of huge samples used in DOE, and thus is able to offer a fast estimation approach for channel in the early design period. In each stage of the vertical flow, the electrical properties of component are extracted by 2.5D or 3D full wave simulator, and thus ensure the accuracy of the channel design. Design strategy for the most crucial discontinuity, Via, to achieve an impedance matching is addressed. Package effect on the COM is also discussed as a reference for adjusting the 3dB criterion of COM in the future.

This article proposes a novel impedance standard substrate, as known as calibration kit, 17 for the calibration using radio frequency (RF) and microwave probes, especially the through 18 substrate which is able to calibrate not only the conventional horizontal but also the vertical 19 interconnects on the basis of the short-open-load-through (SOLT) standardized calibration 20 approach. In the measurement of a vertical connection where the probing ports are located on the 21 opposite surfaces of devices, a location change or rotate with the probes is required after the 22 calibration based on the conventional coplanar kit which only allows the probing in the same 23 plane. The location change or rotation of the probes and corresponding connected cables 24 inevitably affects the precision of the calibration since the probes and cables are sensitive to the 25 surroundings. Our proposed calibration kit can overcome the aforementioned shortcomings, and 26 the comparison of calibrated results between conventional and proposed through impedance 27 standard substrate is demonstrated. Validation of the proposed kit based on the coplanar meander 28 lines and vertical couplings by via arrays is also discussed.