... process2 layersPCB assemblySolder mask: wet green paint, dry green paint, and UV paintBase material: FR-4, 94vo, CEM-1, CEM-3 ... and 94HBSurface finish: hot air solder leveling (tin, tin lead), ... immersion gold (tin, silver), OSP, selective immersion gold and gold plating PCB Assembly and Production Services for Single Side Double Side or Multilayer ...