HDI PCB (High Density Interconnect PCB) contain blind and/or buried vias and often contain microvias of .006 or less in diameter. They have a higher circuitry density than traditional circuit boards.
HDI PCBs are characterized by high-density attributes including laser microvias, fine lines and high performance thin materials. This increased density enables more functions per unit area. Higher technology HDI PCBs have multiple layers of copper filled stacked microvias (Advanced HDI PCBs) which creates a structure that enables even more complex interconnections. These very complex structures provide the necessary routing solutions for today’s large pin-count chips utilized in mobile devices and other high technology products.
HDI Structures: 1+N+1 – PCBs contain 1 “build-up” of high-density interconnection layers; i+N+i (i≥2) – PCBs contain 2 or more “build-up” of high density interconnection layers.