On the simulation of the imaging properties of spike defects

A special phase model was developed to simulate the imaging properties of spike defects in wafer inspection systems, using digital image processing as inspection tools. The main characteristic of spike recognition is its «blinking» with defocus. We can show, that our simple phase model describes the imaging properties in one and two dimensions exactly compared with the experimental results. The influences of the coherence parameter and defocus on the image intensities of spikes are discussed on the base of Hopkins' theory. Special colour effects can be explained with our model too