Investigations of adhesion between Cu and Benzocyclobutene (BCB) polymer dielectric for 3D integration applications

In this paper, the adhesion strength between Cu metal and Benzocyclobutene (BCB) polymer dielectric was investigated and reported. The relation between the adhesion strength and thickness of metal layer and the relation between the adhesion strength and stacking order of copper and BCB polymer layer are discussed as well. Finally, the concept of an extra layer between Cu metal and BCB polymer layer to improve the adhesion strength was evaluated. The results of this research can provide important guidelines of hybrid bonding and underfill for 3D integration applications.