Heat treatment apparatus and heat treatment method for measuring particle concentration

Abstract

A heat treatment apparatus includes a chamber for receiving a substrate therein, and a measurement part for measuring an air particle concentration in a processing space provided in the chamber. An air particle concentration in the processing space provided in the chamber is measured by the measurement part. The air particle concentration is correlated with the number of particles attached to a substrate received in the chamber. Accordingly, by conducting a particle test after the air particle concentration in the processing space is lowered to an air particle concentration corresponding to the number of particles existing on the substrate which can pass the particle test, the number of times the particle test should be conducted after maintenance of the heat treatment apparatus can be reduced.

What is claimed is: 
     
         1 . A cleaning method for cleaning inside of a process chamber of a heat treatment apparatus for heating a substrate, comprising the steps of:
 (a) discharging particles scattered by flashes of light emitted from a flash lamp toward an interior of said process chamber to outside of said process chamber by a stream of gas while preventing a substrate from being transported into said process chamber; and   (b) introducing a gas in a processing space provided in said process chamber into a measurement part and measuring an air particle concentration in the gas, and in a case where said air particle concentration measured in said gas is higher than a reference value, returning to said step (a).   
     
     
         2 . The cleaning method according to  claim 1 ,
 wherein   said step (a) includes the step of:   (a-1) emitting flashes of light from said flash lamp without performing an operation of a driving mechanism in said process chamber; and   said step (b) includes the step of:   (b-1) in a case where an air particle concentration of particles having diameters less than a predetermined size is higher than a reference value, returning to said step (a-1).   
     
     
         3 . The cleaning method according to  claim 2 ,
 wherein   said step (a) further includes the step of:   (a-2) emitting flashes of light from said flash lamp while performing an operation of said driving mechanism in said process chamber; and   said step (b) further includes the step of:   (b-2) in a case where an air particle concentration of particles having diameters not less than said predetermined size is higher than a reference value, returning to said step (a-2).