Patent ID: 7815366
Filing Date: 2010-10-19
Classification: H01L

Abstract:
1. A method of detecting extraneous matter on a heat processing plate to detect extraneous matter adhering to the heat processing plate for mounting and heat-processing a substrate thereon, said method comprising: dividing the heat processing plate into a plurality of regions; detecting a temperature fluctuation of each of the regions when mounting the substrate; evaluating the temperature fluctuations of all of the regions while incorporating, as an evaluation factor, the temperature fluctuations caused by mutual heat transfer between the regions to determine the presence or absence of extraneous matter on the heat processing plate; collecting a plurality of integrated values of temperature fluctuations in each of the regions when mounting the substrate on the heat processing plate in a normal state without extraneous matter; forming a Mahalanobis reference space based on the collected integrated values of temperature fluctuations at normal time; detecting an integrated value of temperature fluctuation of each of the regions when mounting the substrate on the heat processing plate during heat processing; calculating a Mahalanobis distance of the integrated value of temperature fluctuation during the heat processing, based on the detected integrated value of temperature fluctuation during the heat processing and the Mahalanobis reference space; and comparing the Mahalanobis distance to a predetermined threshold value to determine the presence or absence of extraneous matter on the heat processing plate.