IDENTIFICATION OF COMPLICATED SHAPE OBJECTS BY FRACTAL CHARACTERISTICVARIABLES - CATEGORIZING DUST PARTICLES ON LSI WAFER SURFACE

This paper describes a mathematical model of dust particles having com plex shapes, and an algorithm to identify them aiming mainly at catego rizing types of dust on an LSI wafer surface. Fractal dimension is use d to represent the dust features. A conventional fractal dimension app lied to specimens as a whole, however, does not sufficiently represent the shapes of dust in each category of the model. This paper introduc es a local fractal dimension into a global fractal dimension so that t he feature of a mathematical model can be represented. Also proposed i s a method based on Mahalanobis' distance using a fractal characterist ic valuable to categorize the data. The proposed method has been teste d successively by using real data.