The adhesion between several materials implemented in Cu/low-k integration is studied. Adhesion issues at different interfaces are important with regard to the reliability of back-end processing. Layered test structures are processed to study different interfaces. A tangential shear tester allows quantifying the adhesion force at the interface and provides a relative measurement to compare various materials. Failed interfaces are analyzed using auger electron spectroscopy (AES) and scanning electron microscopy (SEM). Among all studied structures, the strongest interface is seen between a barrier (Ti(N), Ta(N), WxN) and Cu. A weaker interface proves to be between a low-k dielectric and Cu. However, the presence of a barrier increases the adhesion. The weakest interface occurs between an oxide cap and the low-k material, with a lower adhesion when the low-k material is fluorinated. The low-k/cap oxide interface forms a critical issue with regard to Cu/low-k integration processing such as chemical mechanical polishing (CMP). All test structures show no significant degradation of the adhesion after a thermal cycle up to 400°C.