Temperature control method and substrate processing apparatus
A temperature control method includes providing a substrate processing apparatus including a processing container, and a heater that heats the processing container; setting an amount of temperature change with respect to a target temperature having a value up to a second digit smaller than a first digit indicating a control limit value of the heater; dividing the amount of temperature change into a first temperature equal to or greater than the first digit and a second temperature less than the first digit, and calculating a ratio of dividing a time segmented by a digit difference between the first digit and the second digit, into a first time corresponding to the second temperature and a second time other than the first time; and controlling the heater to raise or lower a temperature in times before and after dividing a processing time in a processing step at the ratio.
1 . A temperature control method comprising:
(a) providing a substrate processing apparatus including:
a processing container configured to accommodate a substrate; and
a heater configured to heat an inside of the processing container;
(b) setting an amount of temperature change with respect to a target temperature, wherein the target temperature has a value measured to a second decimal place of lesser magnitude than a first decimal place indicating a control limit value of the heater;
(c 1 ) dividing the amount of temperature change into a difference between a first temperature and a second temperature,
said first temperature being greater than or equal to the target temperature and measured to the first decimal place,
said second temperature being less than the target temperature and measured to the first decimal place,
(c 2 ) calculating a ratio by dividing the difference between the first temperature and the target temperature by the order of magnitude between the first and second decimal places,
(c 3 ) multiplying the ratio by a intended process time to obtain a first length of time where the heater is operated at the first temperature, and
(c 4 ) subtracting the first time from the intended process time to obtain a second length of time where the heater is operated at the second temperature; and
(d) controlling the heater to either the first temperature or the second temperature according to the first and second lengths of time such that the heater is operated at the first temperature for the first length of time within the intended process time and such that the heater is operated at the second temperature for the second length of time within the intended process time.
2 . The temperature control method according to claim 1 , wherein the first temperature is obtained by adding 1 to the first decimal place of the second temperature.
3 . The temperature control method according to claim 1 , wherein
the substrate processing apparatus further includes a boat configured to hold a plurality of substrates in a plurality of slots arranged vertically in multiple stages, the boat being loaded into and unloaded from the processing container, and
wherein in (b) to (d), when dividing the plurality of slots into a plurality of zones, the amount of temperature change with respect to the target temperature is set for each zone, and the heater for each zone is independently controlled to operate the heater at the first or second temperature according to the ratio between the first and second lengths of time for each zone.
4 . The temperature control method according to claim 1 , wherein the first temperature is greater than the target temperature.
5 . The temperature control method according to claim 1 , further comprising:
(e) preparing the substrate in the processing container, and processing the substrate in the processing step.
6 . A substrate processing apparatus comprising:
a processing container configured to accommodate a substrate;
a heater configured to heat an inside of the processing container; and
a controller,
wherein the controller controls a process including:
(a) setting an amount of temperature change with respect to a target temperature, wherein the target temperature has a value measured to a second decimal place of lesser magnitude than a first decimal place indicating a control limit value of the heater;
(b 1 ) dividing the amount of temperature change into a difference between a first temperature and a second temperature,
said first temperature being greater than or equal to the target temperature and measured to the first decimal place,
said second temperature being less than the target temperature and measured to the first decimal place,
(b 2 ) calculating a ratio by dividing the difference between the first temperature and the target temperature by the order of magnitude between the first and second decimal places,
(b 3 ) multiplying the ratio by a intended process time to obtain a first length of time where the heater is operated at the first temperature, and
(b 4 ) subtracting the first time from the intended process time to obtain a second length of time where the heater is operated at the second temperature; and
(c) controlling the heater to either the first temperature or the second temperature according to the first and second lengths of time such that the heater is operated at the first temperature for the first length of time within the intended process time and such that the heater is operated at the second temperature for the second length of time within the intended process time.