Adhesion between photosensitive epoxy and electroless copper

Abstract

The adhesion between the photosensitive epoxy and electroless copper was measured with a pull test designed and executed in this work. The test pads were fabricated on the substrate by using semi-additive plating process. The pull strength was measured with a mechanical tester. The chemical treatment was used to roughen the polymer surface, two sets of specimens were tested with different swelling time and etching time to get the optimal adhesion strength. Effects of the chemical treatment on surface morphology and adhesion were studied. The surface morphology of the polymer was examined with optical microscopy and the SEM/EDS technique. The ranges of swelling time and etching time, which result in good adhesion, were given. It was confirmed that the swelling and etching processes have to be optimised with respect to each other for achieving the desired polymer surface properties without altering the bulk properties.