Advanced Functional Techniques for Delay Testing of Digital ICs = Advanced Functional Techniques for Delay Testing of Digital ICs

With the shrinking of integrated circuit dimensions and the increasing of the operating frequency, the effect of submicron defects has become so relevant that is no more possible to neglect it. As a consequence, semiconductor manufacturers have to ensure the quality of their products with respect to these defects, especially for those critical application fields, such as medical, spatial or automotive. End-of-manufacturing tests represent a standard step in the fabrication process of any digital device, nevertheless traditional testing methods sometimes do not effectively address today’s issues. This is because traditional models do not take into consideration the effect of defects in nanometer design, therefore new test models must be considered as well as the techniques to use them. Traditional delay testing considers defects that cause a large additional delay in the signal propagation, leading the device to a misbehavior condition. As the system frequency increases, the effect of smaller defects cannot be ignored, since the device becomes more sensitive even to the smallest additional delay. By definition, a functional method is able to run a test exciting the device to test at the same frequency of the normal operating mode