Originally published at: https://www.protoexpress.com/blog/how-to-design-hdi-pcb-stackup/
When designing an HDI PCB stack-up, you need to choose the right build-up architecture and define a via strategy that supports the routing density and impedance needs. For example, use microvias to breakout fine-pitch BGAs, select a 1+N+1 or 2+N+2 build-up depending on fanout difficulty, and ensure symmetrical layer construction to maintain manufacturability and reliability. Likewise, pick materials with stable Dk/Df for high-speed interfaces and validate every stack-up choice with your fabricator’s lamination and laser-drill capabilities. In this article, you’ll learn when to choose high-density interconnect boards, how HDI PCB stack-ups are classified, steps to estimate the layer count, and…