Al-1wt.%Si-0.5wt.%Cu films and passivated lines of different thicknesses varying from 1 mum to 0.4 mum are studied. High thermal stresses are present in such systems. Macroscopic stresses are determined using different X-ray stress measuring approaches, i.e. (1) the classical d-sin(2)psi method; (2) the LIBAD method (Low Incident Beam Angle Diffraction, especially developed for stress measurements in thin layers) and (3) the crystallite group method. Thermal stresses are calculated using the finite element method and compared to the experimentally obtained stresses.