A three-dimensional integrated circuit (3D-IC) refers to a type of semiconductor device that vertically integrates multiple layers of circuitry to create a single compact unit. It enables higher levels of performance and energy efficiency compared to planar 2D devices. Synonyms for 3D-IC include stacked ICs, vertical ICs, multilayered ICs, and layered ICs. Another synonym is through-silicon-via (TSV) technology, which refers to the vertical interconnects used to connect the different layers of the 3D-IC. These technologies have gained significant traction in recent years due to their ability to pack more functionality into a smaller area, making them ideal for mobile devices and other compact electronics.