US 2026/0092701 A1Published application

Superheated-steam generating method and superheated-steam generating apparatus

AssigneeEbara Corporation

InventorsRyota YAMAOKA, Shumpei MIURA, Yasuyuki MOTOSHIMA, Nozomu KUWABARA, Seiya HIGUCHI, Yukihiro KANG

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Abstract

A superheated-steam generating method that can quickly generate superheated steam and can prevent the superheated steam from reaching an excessively high temperature is disclosed. The superheated-steam generating method includes: determining a heater-temperature command value for minimizing a temperature difference within a first heater-temperature allowable range set for a first time segment; increasing the first heater-temperature allowable range by a predetermined upward shift amount to determine a second heater-temperature allowable range when the measured value of the temperature of the steam in the first time segment is smaller than the target temperature of the superheated steam and the temperature difference is larger than a first threshold value; and determining the heater-temperature command value for minimizing the temperature difference within the second heater-temperature allowable range set for a second time segment.

Claims6

Dependent claims

A superheated-steam generating method of generating superheated-steam for use in regulating a surface temperature of a polishing pad for polishing a substrate, comprising:

heating water to generate steam by a steam generator having a heater;
measuring temperature of the steam by a steam-temperature measuring device;
and
determining, by a feedback controller, a heater-temperature command value indicating a set temperature of the heater for minimizing a temperature difference between a measured value of the temperature of the steam and a target temperature of the superheated steam,
wherein determining the heater-temperature command value by the feedback controller comprises:
determining the heater-temperature command value for minimizing the temperature difference within a first heater-temperature allowable range set for a first time segment;
increasing the first heater-temperature allowable range by a predetermined upward shift amount to determine a second heater-temperature allowable range when the measured value of the temperature of the steam in the first time segment is smaller than the target temperature of the superheated steam and the temperature difference is larger than a first threshold value;
and
determining the heater-temperature command value for minimizing the temperature difference within the second heater-temperature allowable range set for a second time segment.

6 more elements

A superheated-steam generating apparatus comprising:

a steam generator having a heater configured to heat water to generate steam;
a steam-temperature measuring device configured to measure temperature of the steam;
and
a feedback controller configured to determine a heater-temperature command value indicating a set temperature of the heater for minimizing a temperature difference between a measured value of the temperature of the steam and a target temperature of superheated steam,
wherein the feedback controller is configured to:
determine the heater-temperature command value for minimizing the temperature difference within a first heater-temperature allowable range set for a first time segment;
increase the first heater-temperature allowable range by a predetermined upward shift amount to determine a second heater-temperature allowable range when the measured value of the temperature of the steam in the first time segment is smaller than the target temperature of the superheated steam and the temperature difference is larger than a first threshold value;
and
determine the heater-temperature command value for minimizing the temperature difference within the second heater-temperature allowable range set for a second time segment.

6 more elements

Dependencies are inferred from the claim text.