Thermal management for three-dimensional integrated circuits (3D ICs) is becoming a crucial challenge. In this paper, we propose new cooling architectures using thermal sidewalls, interchip plates, and a bottom plate (thermal-SIB architectures) for 3D systems that have a power dissipation of several tens to a couple of hundred W/cm2 as a vertical addition. There are several types of sidewalls: cap, bridge, poles, and comb. The thermal-SIB architectures can secure heat conduction paths to a heat sink that removes most of the heat generated in the devices. The experimental results obtained by using a 3D thermal solver demonstrate that the proposed architectures that have some structural variations can significantly reduce the maximum temperature in a 3D IC. Specifically, the basic structure could reduce the temperature rise by over 40% compared with the conventional structure that uses only a heat sink.