This document contains tags and descriptions for various printed circuit board (PCB) manufacturing topics including types of PCBs (such as 6 layer ENIG PCB and flexible PCB), PCB finishing processes (such as HASL and ENIG), materials used in PCB manufacturing (such as fiberglass and copper), and other related terms (such as pull-up and pull-down resistors). The tags provided are meant for search engine optimization and grouping related terms.