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Introduction
As the functionalities of portable devices such as tablet computers, smart phones, and smart watches continue to expand, system-on-a-chip (SoC) designs for such devices have become increasingly complex. For next-generation integrated circuit (IC) design, the development of three-dimensional-integrated circuits (3D ICs) is expected to replace SoC designs and offers significant advantages related to high-performance and low-power portable devices in the near future [1–3]. However, the fabrication of 3D ICs using advanced process technologies may induce extremely high-power density leading hot spots. Consequently, the hot spots may result in degradation of performance and reliability with growth of power consumption for ICs, such as (i) increasing the delay time of ICs, (ii) increasing the probability of timing violations in ICs, (iii) increasing the error rate of memory accesses, (iv) shortening the lifetime of ICs, and (v) increasing the leakage power consumption of ICs [4, 5]. More extensive cooling devices may be needed to suppress the hot spots. Therefore, effective techniques for predicting and minimising the adverse effects of the hot spots are urgently required.
Thermal analysis (TA) techniques at architectural level are proposed to predict the temperatures of ICs at the early stages of IC design, through heat transfer analysis using information on ICs, such as floorplan and power consumption [6–15]. When integrated with thermal management techniques such as task migration, power gating, and dynamic voltage and frequency scaling in virtual platforms to co-design, co-simulate, and co-verify software and hardware by the methodology of electronic system-level design at the early stages of IC design [16], the temperatures of the hot spots can effectively be minimised, thus reducing the cost of IC design as well. For better reflecting physical–thermal runaway effect in TA, the thermal effects in temperature-dependent factors (such as leakage power [17, 18] and thermal conductivity [19–21]) need to be considered. Furthermore, thermal radiation and convection [19, 20] on the boundaries adjacent to the ambient environment should be considered because these mechanisms impact heat dissipation. Thus, the physical–thermal interactive effects of ICs at the early stages of IC design can be effectively reflected by considering these factors in TA.
Nowadays, the TA techniques integrated into thermal simulators of ICs have been studied in [6–15]. However, the TA in [6–15] nearly neglects the temperature-dependent factors. Hence,...