50031

Electroplating failure analysis  

September 18, 2008

Hi,

I am working in electroplating industry as process engineer ,

we have several problems in plated parts
1.stain in A-2 PLATING , TOFSIMS AND EDX shows high sodium and carbon content in stained part . we never use sodium in plating process ,but how sodium concentration increases ?

2.In nickel -nickel phosphorous plating the grain size in the SEM IMAGE VARIES THE ONE WITH WELL DEFINED GRAIN SIZE SUITABLE FOR WIRE BONDING WHEREAS the other film like not suitable for wire bonding

3.The frame plated with cu alloy 7205 shows copper pealing after 1 month

please give suggestions to solve the above problems

Thanks & regards
k.ganga

KANNAIYAN GANGA
PROCESS ENGINEER - SINGAPORE

Hi, K.

1. Sorry, but I don't know what you mean by A-2 Plating. You have good tools there but I have never enjoyed success in fixing a plating problem by analysis of the plated part, only by starting back at the plating tank. What name does your plater assign to these stains?

2. Does nickel - nickel phosphorous mean that you do both electrolytic and electroless nickel on the parts? The well-defined grain may be large soft grains resulting from minimal use of brighteners in an electrolytic process; brighteners may make it difficult to wire bond.

3. When copper or other plating peels it usually indicates that the substrate was not properly pretreated; either it was not truly clean, or the passive metal surface was not properly activated.

Please try to spend some time right at the plating line and tell us what kind of stuff you are seeing there. Good luck.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Regarding wire bonding. It appears tha you are using electroless nickel. High Phosphorus (10% or more) deposits with a small grain size. The high phosphorus interferes with wire bonding. The larger crystallites indicate low phosphorus and better wire bonding. Ultrasonic bonding on nickel requires higher energy than for bonding to copper, gold. Higher energy not more pressure.

Don Baudrand Don Baudrand, Consultant   Poulsbo, Washington