Detecting gate-oxide shorts and delay defects in CMOS IC´s

Defect analysis was performed to show the relationship among process defects, gate-oxide short defects, and delay effects, SPICE transient analysis was used to find the propagation delay of the voltage response across the defective circuit. At the same time, power supply currents at static states were measured to find the correlation of static IDD currents and delay defects. It is shown that the IDD test is very effective for node-to-node short detection. However, a large class of defects cannot be detected using the IDD test. It is concluded that a testing method which combines IDD and stuck-fault testing is necessary to ensure a high level of product quality