HDI is a necessity when the component pitch requires it or the board size demands it. Examples of this include smartphones, wearable technology, and robotics. A properly designed HDI PCB Board enables a smaller board (board size goes down), or enables two through-hole (TH) boards being combined into one board (pins per area goes up). A properly designed HDI PCB has 2X to 3X more average trace lengths per layer that a through-hole board. Some very good HDI designers report 4X performance. So know what your current through-hole design density performance is, and you’ll be able to determine good HDI design performance. HDI PCB boards are much harder to plan then traditional multilayer boards because, with multilayer, you only have two degrees of freedom, boards size, and signal layers.
HDI has a myriad of constructions and variables that all affect density. To understand how blind vias, skip vias, staggered vias, stacked vias and buried vias contribute to density, you have to do a “Routing Test” and play with all these different stackups and constructions. By measuring the metrics (inches/square inch and pins/square inch), you can create a table that relates these density measures to the corresponding construction.
If you want to know more about HDI PCB Board, please feel free to contact MKTPCB.