Method for etching a sample

The invention provides a method for performing mass production processing of etching a sample capable of maintaining a stable processing profile. The method for performing mass production processing of etching for subjecting a wafer carried into a vacuum processing reactor to plasma processing uses an apparatus comprising a vacuum processing chamber, a gas supply apparatus, a plasma generating means for generating plasma, an emission spectroscope for monitoring the plasma emission, and a device for storing the emission spectrum, wherein a non-operating time of the apparatus (idling SS) occurs in which the mass production processing of the wafer is temporarily stopped, wherein during cleaning steps S2 and S2′ before and after idling SS, emission intensities SiF(1) and SiF(2) in the plasma including the information on the state of deposition of reaction products and the temperature on the uppermost surface of the reactor are monitored, and a database S4 is referred to based on these emission spectrums, so that the time of the plasma heating step S3 after the idling SS is controlled to heat the reactor, and after performing plasma heating S3, the next sample is subjected to etching S2.