Patent ID: 6794203
Filing Date: 2004-09-21
Classification: H01L

Abstract:
A method of selecting a sensitivity to count particles in a pre-process, by which a counting of added particles during the process will be more correct, the method comprising the steps of:counting particles in a pre-process in respect of a plurality of sensitivities; counting particles in a post-process under a certain sensitivity; finding the count of corresponding particles appearing in both of the pre-process and the post-process in respect of respective sensitivities; calculating respective mapping rates and respective catching rates of respective sensitivities, the mapping rate resulting from dividing the count of corresponding particles in respect of one sensitivity by the count of particles in the preprocess of such one sensitivity, and the catching rate resulting from dividing the count of corresponding particles in respect of one sensitivity by the maximum count of corresponding particles under a comparison in respect of all sensitivities; selecting a sensitivity having a maximum summation of the mapping rate and the catching rate with respect to a same sensitivity.