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 pro cessing as inspection tools. The main characteristic of spike recognit ion is it's ''blinking'' with defocus. We can show, that our simple ph ase model describes the imaging properties in one and two dimensions e xactly compared with the experimental results. The influences of the c oherence parameter and defocus on the image intensities of spikes are discussed on the base of Hopkins' theory. Special colour effects can b e explained with our model too.