Surface roughness effect on copper–alumina adhesion

• We have examined the alumina substrate with three different surface roughness and compare their adhesive strength.
• We have estimated the surface area based on these surface roughness using AFM 2D model.
• Area in contact increases with surface roughness.
• Bonding strength at the interface increases with surface roughness.
• Increment of bonding strength is mainly due to the area in contact.

The surface roughness of the substrate itself could play an important role for the bonding at the interface. In this paper, a correlation of the surface roughness of a rigid alumina substrate and its 2D model of estimated surface area has been studied using Atomic Force Microscopy (AFM). With rougher surface, the adhesive strength between a deposited copper film and the alumina substrate is higher due to the larger contact area at the interface. For 99.99% pure copper–96% pure alumina, this effect can account for an adhesive strength increment of more than 50%.