Bulging defect in copper plating layer

Hello,

My name is Faizul and I am working in an electroplating company as an engineer. My company does electroplating mostly for lead frames used in semiconductor industries; recently my production faced copper bulging on the surface of lead frame.

Raw material is iron and I do not know what types of iron. Dk used for copper strike is 1.43 Amp/dm2 and for copper plating is 3.00 Amp/dm2. We have tried increasing the copper strike Dk to 4.00 Amp/dm2 and the bulging was reduced but we still have it. We also have manipulated the agitation direction to face the copper anode, product and to the bottom. It seems that agitation to the bottom with the solution flow calm is the best. For your info we apply only copper strike as an undercoat before copper plating. Both solution concentration within control limit and impurities are within control. Hope you can explain the mechanism how it is happened and how to overcome it. Thank you.

Faizul

Hi, Faizul.

Obviously, ALL parameters must be under proper control for proper plating, but incorrect current density or improper agitation does not usually manifest itself with blistering, but with burning. Blistering could indicate either extreme compressive stress (unlikely), but more likely is evidence of poor adhesion. The cause of poor adhesion is usually an improperly cleaned or activated substrate, or a poorly functioning strike solution.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

It begs the question, Is it a cyanide or pyrophosphate or ?? strike solution?

Copper is cyanide based. Strike solution is low concentration solution used as a undercoat before plating