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PWB mfgr has thickness control issues on Au and Nickel in ENIG process

2003

What is the normal RANGE that nickel and gold can be controlled in a Electroless Nickel Immersion Gold Line?

Does High carbon content on the product indicate the bath has high carbon content, how can this be measured and monitored?

What could be the possible causes for a failure of aluminium wire bonding on the nickel layer.

Nirmala
printed circuit board fabrication - Bayan Lepas Industrial Estate, Penang, Malaysia

Expect ± 40% thickness with immersion gold. EN depends on process control but at best is ±15%. If measuring using XRF, the nickel thickness is very inaccurate under gold. Carbon can be found in trace amounts, unless it's electroless gold, which may contain 1-2% organic co-deposits. A hot DI soak after gold sometimes helps with wirebonding as well as the carbon. Also keep the gold >0.1 micron, and the nickel 1.5 microns.

Kevin Keating
medical device - Rochester, New York
2003