Beijing PCB Assembly Bonding 1Layer1-16 layer2MaterialFR-4, CEM-1, CEM-3, High-TG, FR4, Halogen Free, FR-1, FR-2, Aluminum3Board thickness0.2mm-4mm4Max. finished board side500mm*500mm5Min. drilled hole size0.25mm6Min. line width0.075mm (3mil)7Min. line spacing0.075mm (3mil)8Surface finishingHALS/HALS lead free, Chemical tin9Copper..