Copper Adhesion on Copper

Letter 2055

Copper Adhesion on Copper

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Recently, we are facing the problem of copper peeling. A thin layer of copper is striked onto copper base material. After applying heat (350 deg C) for one minute, the top layer crack and peel off (suspect is the oxide layer).The bath used is a copper cyanide bath. Please provide advice on this matter, if necessary, we are willing to try new copper bath. Thanks.

Patrick Soh

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You say nothing about your surface preparatrion and little about the quality of the copper finish going in to the process.

Clean thoroughly (usually recommended to use a high temperature alkaline soak), possibly electroclean following that, and final deoxidize with acid, cyanide, or a chelating cleaner. Then the plating, particularly if from a cyanide copper strike bath, should stick.

Bill Vins
microwave & cable assemblies
Mesa (what a place-a), Arizona

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You say you plate Cu on Cu, but I guess the basematerial is a copper ally. If the Cu-layer you electroplate is porous (And I guess it is) and your base contains dispersed alloying elements, than you can have severe oxidation of these elements on the surface. Try in that case an increase of you copper layer thickness or degrease anodically with high sodiumhydroxide content in your cleaner.

Success and let us ever know how you solved you're problem.

Harry van der Zanden
Netherlands

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I have encountered adhesion problem of electroless coppper plating on fully cured polyimide substrate. The electroless copper, which is about 2.5 microns thick was seen blistering and peeled off easily from the polyimide surface after the plating process. The polyimide used was cured at 350 deg C for 30 mins before the plating process. Can anyone advise me on resolving the adhesion problem, Thanks.

Regards

Goh
- Singapore

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