This document contains tags and metadata for various topics related to printed circuit boards and PCB manufacturing, including types of PCBs (e.g. 2 layer, 4 layer, multilayer), PCB finishing processes (e.g. HASL, ENIG, immersion gold), and other related terms (e.g. equipment, quality assurance, technology). The tags provided would help with searching and organizing information about PCBs and the PCB manufacturing process.