A convenient nanoscratch method was combined with atomic force microscope(AFM) and transmission electron microscope (TEM) observations to conduct thefirst-ever evaluation of the adhesion strength of a complicatedmicrostructureCu/Ta/TaN/pSiO2/low-k/SiC/pSiO2/Si-substrate with theaim of correlating the fracture strength with the results of chemicalmechanical polishing (CMP) tests. Concretely, this evaluation focused on thefact that specimens having a low-k layer pretreated with rare-gas plasmaprior to the deposition of the SiO2 layer exhibited lowdelaminated densities in the Cu CMP process. It was found that a specimenwith the rare-gas plasma pretreatment exhibited a higher frictioncoefficient, a higher critical load and brittle adhesive failure resultingfrom delamination at the interface between the low-k and SiC layers. Aspecimen without the rare-gas plasma pretreatment displayed a lower frictioncoefficient, a lower critical load, and ductile cohesive failure in thelow-k layer. Because less plastic deformation was observed in the low-klayer subjected to the rare-gas plasma pretreatment, it is assumed that thepretreatment reinforced the mechanical properties of the low-k layer, makingit more resistant to ductile cohesive failure. These results agreed with theCMP test data and indicated that the nanoscratch method makes it possible topredict the ability of complicated Cu/low-k interconnect structures towithstand the CMP process.