Method for purge clean of low pressure furnace

A method for purge clean of a low pressure furnace, comprising the following steps:

• step 1, providing a process chamber of the low pressure furnace in a standby state, wherein an inner wall thin film formed by a furnace deposition process is accumulated on the surface of an inner wall of the process chamber;
• step 2, performing temperature ramp-up and/or temperature ramp-down treatment on the process chamber to generate first thermal stress in the inner wall thin film, wherein thin film particles with poor adhesion in the inner wall thin film peels off due to release of the first thermal stress, the thin film particles with poor adhesion refer to thin film particles that will peel off during the subsequent furnace deposition process thin film particles, and the first thermal stress is greater than second thermal stress formed in the inner wall thin film during the furnace deposition process;
• wherein step 2 comprises the following substeps:
• step 21, performing the first temperature ramp-up treatment on the process chamber, wherein the first temperature ramp-up treatment ramps up the temperature of the process chamber from a standby temperature to a first temperature at a first temperature ramp-up rate, and during the first temperature ramp-up treatment, the first thermal stress is temperature ramp-up thermal stress and the first thermal stress becomes larger when the first temperature ramp-up rate becomes larger;
• step 22, performing high-temperature thermostatic treatment on the process chamber at the first temperature;
• step 23, performing the temperature ramp-down treatment on the process chamber, wherein the temperature ramp-down treatment ramps down the temperature of the process chamber from the first temperature to a second temperature at a second temperature ramp-down rate, the second temperature is less than the standby temperature, and during the temperature ramp-down treatment, the first thermal stress is temperature ramp-down thermal stress and the first thermal stress becomes larger when the second temperature ramp-down rate becomes larger;
• step 24, performing low-temperature thermostatic treatment on the process chamber at the second temperature;
• and
• step 25, performing the second temperature ramp-up treatment on the process chamber, wherein the second temperature ramp-up treatment ramps up the temperature of the process chamber from the second temperature to the standby temperature at a second temperature ramp-up rate, and during the second temperature ramp-up treatment, the first thermal stress is temperature ramp-up thermal stress and the first thermal stress becomes larger when the second temperature ramp-up rate becomes larger;
• step 3, introducing a cleaning gas in a pulse manner to perform cycle purge clean on the process chamber, so as to remove the peeling thin film particles from the process chamber;
• and
• step 4, switching a state of the process chamber to the standby state after the cycle purge clean ends.