What is Immersion Gold ?
by cawan (cawan[at]ieee.org or chuiyewleong[at]hotmail.com)
Before a blank PCB is ready for PCBA, if there are a lot of extra small scale SMDs being used
such as 0603, 0402, 0201..., or high density BGA, then it is recommended for immersion gold
to the blank PCB. The main objective of immersion gold is to provide better contactness for
those SMDs to the pads, in order to reduce the failure rate in mass production. Of course this
will induce extra production cost, but the impact is significant. For those who can't tolerate
to the extra cost, consider to immersion silver or stick to immersion tin instead.