1. A method for prognostic maintenance in semiconductor manufacturing equipments, comprising the steps of: collecting a plurality of raw data and preprocessing the plurality of collected raw data to filter out meaningless null detection values existing in the plurality of raw data and generate detection values of normal pattern; performing classification through a statistic classification model on the plurality of preprocessed raw data to generate a plurality of health indices; performing classification on the plurality of generated health indices by a prescribed classification method to generate a plurality of health information; using a regression analysis method to process the plurality of health information to generate a plurality of health reports; and performing repairs and maintenance actively by in-situ engineers based on the plurality of generated health reports.