Jim,

Have you determined if the cracks are present
in the plated hole wall copper also?  I am just
going to assume they are.

What does your grain structure look like?  Is 
it equiax or columnar?  Does it change from one
structure to another through the thickness of the
plating?

Causes can be additive concentrations (grain refiners)
or current density or copper purity or codeposited organics.

Susan Mansilla
Robisan Laboratory
317-353-6249 

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