Fracture behavior of an ultra thin Aluminium foil was studied. For very short crack lengths, fracture has been followed in the scanner electronic microscope (SEM) with a tensile stage. A single edge notched tension specimen was used. Crack length and applied load during the crack growth were measured. These results have been used to calculate fracture strength using linear elastic fracture mechanics and a strip yield model. The results are discussed in general and in particular regarding the importance of process region modeling.