IPC-2226 defines HDI as a printed circuit board with a higher wiring density per unit area than conventional printed circuit boards (PCB). They have finer lines and spaces ≤ 100 µm / 0.10mm, smaller vias (<150 µm) and capture pads <400 µm / 0.40mm, and higher connection pad density (>20 pads/cm2) than employed in conventional PCB technology.