Materials play a large role in terms of manufacturability and direct cost of your circuit board. Here is a tip: The goal is always to select the right material for manufacturability that, at the same time, meets your temperature, and your electrical requirements. When it comes to materials, make sure that your high-speed material is also suitable for your HDI design. They are many other factors that come into play when selecting the proper materials for your design.

At some level of circuit complexity, turning to an architecture with blind and buried vias will result in better yield and lower cost than would a through-hole design.

It is very safe to assume it is +/- 1 mil accuracy. Usually, in a staggered microvia formation, the diameters of both operate and lower microvias are the same. The key parameter that decides whether the staggering is possible or not, without the lower microvia needing to be filled, is the dimension E, the vertical separation between the central access of the two microvias. For staggering to be viable, the value of E must be greater than the microvia diameter.

HDI PCBs help reduce costs by decreasing size, minimizing the number of components, reducing signal interference, and automating the manufacturing process.

IPC-2226 defines HDI as a printed circuit board with a higher wiring density per unit area than conventional printed circuit boards (PCB). They have finer lines and spaces ≤ 100 µm / 0.10 mm, smaller vias (<150 µm) and capture pads <400 µm / 0.40 mm, and higher connection pad density (>20 pads/cm2) than employed in conventional PCB technology.

Yes, HDI PCBs usually cost more due to complex manufacturing processes, but the benefits in performance and size often justify the higher price.