High density interconnects (HDI) are defined as substrates or boards with a higher wiring density per unit area than conventional printed circuit boards (PCB). They have finer lines and spaces (<75 µm), smaller vias (<150 µm) and capture pads (<400 µm), and higher connection pad density (>20 pads/cm2) than employed in conventional PCB technology. HDI is used to reduce size and weight, as well as to enhance electrical performance. In addition to HDI, terms such as "build-up board" in Japan and "sequential build-up (SBU)" or "microvia technology" in the U.S. can be used interchangeably.