Abstract
The ductility of fine‐grained 
electroless copper deposits was found to vary with the type of substrates that they were plated on; under identical plating conditions, the ductility of the electroless copper grown on activated plastic substrates was higher than that grown epitaxially on a large‐grained copper foil. This ductility difference is shown to originate from a difference in the void structure developed at the grain boundaries of the deposits during film formation.