Routing a high-density interconnect circuit board is a fundamentally different exercise from routing a conventional multilayer PCB. The reduced pad pitch, fine-pitch BGAs, and increased pin counts demand a routing strategy that starts long before the first trace is drawn. A successful HDI layout depends on selecting the right via architecture, planning escape routing around tight component placements, and validating the design against both signal integrity and manufacturing constraints. When designers approach HDI routing as an integrated process rather than a series of isolated fixes, they can lower layer count, improve yield, and achieve cleaner power distribution. What Makes HDI PCB Routing Different from Conventional PCB Design Conventional PCB routing…