Patent ID: 9612178
Date: 2017-04-04
CPC Classifications: C23C,G01M,G01N,H01L

Claim:
1. A particle monitoring method of monitoring particles included in an exhaust gas from a depressurized processing vessel, in which a process is performed on a substrate, the particle monitoring method comprising: cleaning an inside of the depressurized processing vessel by dispersing the particles through processes of supplying a purge gas into the depressurized processing vessel to apply a shock wave, and then, supplying a high voltage intermittently to apply an electromagnetic stress to the depressurized processing vessel; counting the particles included in the exhaust gas from the depressurized processing vessel while cleaning the inside of the depressurized processing vessel by a counting unit; creating a histogram showing a relationship between time and the number of the particles from a result of the counting of the particles; extracting, from the histogram, a first feature amount indicating a correlation between the most frequent value of the number of the particles and a particle counting period; extracting, from the histogram, a second feature amount indicating a correlation between the particle counting period and a distribution tendency of the particles whether particles dispersed by the shock wave of the purge gas are dominant or whether particles dispersed by the electromagnetic stress are dominant during the particle counting period; and changing a condition for the cleaning of the inside of the depressurized processing vessel based on the distribution tendency of the particles.