During the development of an IC, from the very first project steps, is fundamental to identify the testing strategy. In fact, modern process technologies and design tools allow the realization of really complex chip in which are present million of transistors and the possibility that one of them doesn't work correctly is very high. Before selling a chip, it is necessary to test it, in order to be sure that the IC is working properly. The manufacturing tests are performed in order to guarantee the correct behavior of the IC. Increasing the complexity of the ICs, also means increasing the time needed for the manufacturing tests.