Introduction: large-density HDI PCBs for optical communication need specific three mil/3 mil trace/Place, Rogers or Panasonic M6 substrates, and electrolytic difficult gold finish for dependable 8-layer, 3–5 cm² https://bookmarkpagerank.com/story21728629/assortment-standards-for-top-density-hdi-pcb-boards-in-optical-conversation