35um copper finish double-sided layer latest custom solder mask HASL Chinese FR4 circuit board supplier with UL ISO standard qualified

Immersion Gold 4u'' 4 Layer Fr4 PCB Etching Printing

Immersion Gold is that ENIG (Electroless Nickel Immersion Gold) is an expensive and normal surface finish. Our Capability for Gold thickness can be 1u''-5u'' for Immersion Gold.