This paper presents modeling, simulation and experimental measurements of copper-based TSV for 60-GHz applications. We have considered different via dimensions for modeling and simulations and performed simulations to validate electrical performance of the TSV with varying data rates in addition to providing eye diagram analysis. To validate the electrical model, we performed TSV characterization by fabricating an interconnect using copper material on a silicon substrate.
IntroductionThrough Silicon Vias (TSVs) have attracted increasing interest in the computer, circuits and devices, and packaging communities due to their shorter vertical interconnect path, resulting in lower parasitic losses, reduced power consumption, higher I/O density and improved system performance. TSVs, which can be fabricated on individual wafers and vertically interconnected, play a critical role in integrating heterogeneous technologies. They are particularly attractive for next-generation consumer and computing applications that demand faster signal processing speed, ultrahigh I/O density, smaller foot-print area, improved electrical performance and reliability.Continuously evolving interconnect technology has been a major factor complementing the 3-D integration scheme and has contributed significantly to the realization of high-density and multifunctional microelectronics [1]. Low-cost, reliable via formation technologies, proper choice of materials for via filling and innovative design solutions that address electrical and thermal issues must now be rigorously investigated [1,2]. Along with the need for low-cost and high-yield process technology, the successful application of TSV technology should be accompanied by optimal electrical design. The electrical design of TSV interconnections requires careful consideration of complex electrical behavior. Through silicon vias are fabricated in lossy silicon substrates and are exposed to coupling, distortion and additional losses [3]. When TSVs are used for high frequency applications, SiO 2 cannot be used as an insulating layer due to its high fringing capacitance. Instead a polymer like benzocyclobutane (BCB) is used as an insulating layer, and a conformal coating is achieved by using a deep reactive ion etching process. Therefore, it is of utmost importance to obtain an electrical model of TSV by considering different modeling constraints to achieve an optimal design solution.For wireless applications, designers and engineers are exploring the 60-GHz band to utilize the advantages it offers over current frequency bands. The 60-GHz band is an unlicensed band featuring a large bandwidth that allows a large number of bits to be transmitted at a faster rate.