Supercritical drying method for semiconductor substrate

Abstract

In one embodiment, after rinsing a semiconductor substrate having a fine pattern formed thereon with pure water, the pure water staying on the semiconductor substrate is substituted with a water soluble organic solvent, and then, the semiconductor substrate is introduced into a chamber in a state wet with the water soluble organic solvent. Then, the water soluble organic solvent is turned into a supercritical state by increasing a temperature inside of the chamber. Thereafter, the inside of the chamber is reduced in pressure while keeping the inside of the chamber at a temperature enough not to liquefy the pure water (i.e., rinsing pure water mixed into the water soluble organic solvent), and further, the water soluble organic solvent in the supercritical state is changed into a gaseous state, to be discharged from the chamber, so that the semiconductor substrate is dried.

1 .- 12 . (canceled) 
     
     
         13 . A supercritical drying method for a semiconductor substrate comprising:
 cleaning the semiconductor substrate with a chemical solution;   rinsing the semiconductor substrate with pure water to cover a surface of the semiconductor substrate after the cleaning;   supplying a water soluble organic solvent onto the semiconductor substrate after the rinsing, to replace the pure water covering the surface of the semiconductor substrate with the water soluble organic solvent;   supplying a first water insoluble organic solvent onto the semiconductor substrate after the replacing;   introducing the semiconductor substrate into a chamber, the surface of the semiconductor substrate being covered with the first water insoluble organic solvent;   supplying a second water insoluble organic solvent into the chamber;   setting a temperature inside of the chamber at a critical temperature of the second water insoluble organic solvent or higher, to turn the second water insoluble organic solvent into a supercritical state; and   after turning the second water insoluble organic solvent into the supercritical state, decreasing a pressure inside of the chamber while keeping a temperature inside of the chamber at a predetermined value which is equal to or more than a boiling point of the water soluble organic solvent, to turn the second water insoluble organic solvent in the supercritical state into a gaseous state, thus discharging the second water soluble organic solvent from the chamber.   
     
     
         14 . The supercritical drying method according to  claim 13 , wherein the predetermined value is a temperature at which the steam pressure of the water soluble organic solvent becomes higher than a critical pressure of the second water insoluble organic solvent. 
     
     
         15 . The supercritical drying method according to  claim 14 , wherein the steam pressure of the second water insoluble organic solvent is higher than that of the water soluble organic solvent. 
     
     
         16 . The supercritical drying method according to  claim 15 , wherein the water soluble organic solvent includes alcohol or ketone, and further, one of the first water insoluble organic solvent and the second water insoluble organic solvent includes any one of alcohol fluoride, hydrofluoroether (HFE), chlorofluorocarbon (CFC), hydrofluorocarbon (HFC), and perfluorocarbon. 
     
     
         17 . The supercritical drying method according to  claim 13 , wherein the first water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         18 . The supercritical drying method according to  claim 13 , wherein the second water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         19 . The supercritical drying method according to  claim 13 , wherein the predetermined value is equal to or more than 200° C. 
     
     
         20 . The supercritical drying method according to  claim 13 , wherein the water soluble organic solvent is isopropyl alcohol (IPA). 
     
     
         21 . A supercritical drying method for a semiconductor substrate comprising:
 cleaning the semiconductor substrate with a chemical solution;   rinsing the semiconductor substrate with pure water to cover a surface of the semiconductor substrate after the cleaning;   supplying a water soluble organic solvent onto the semiconductor substrate after the rinsing, to replace the pure water covering the surface of the semiconductor substrate with the water soluble organic solvent;   supplying a first water insoluble organic solvent onto the semiconductor substrate after the replacing;   introducing the semiconductor substrate into a chamber, the surface of the semiconductor substrate being covered with the first water insoluble organic solvent;   supplying a second water insoluble organic solvent into the chamber;   setting a temperature inside of the chamber at a critical temperature of the second water insoluble organic solvent or higher, to turn the second water insoluble organic solvent into a supercritical state; and   after turning the second water insoluble organic solvent into the supercritical state, decreasing a pressure inside of the chamber while keeping a temperature inside of the chamber at a predetermined value which is equal to or more than 200° C., to turn the second water insoluble organic solvent in the supercritical state into a gaseous state, thus discharging the second water soluble organic solvent from the chamber.   
     
     
         22 . The supercritical drying method according to  claim 21 , wherein the predetermined value is a temperature at which the steam pressure of the water soluble organic solvent becomes higher than a critical pressure of the second water insoluble organic solvent. 
     
     
         23 . The supercritical drying method according to  claim 22 , wherein the steam pressure of the second water insoluble organic solvent is higher than that of the water soluble organic solvent. 
     
     
         24 . The supercritical drying method according to  claim 23 , wherein the water soluble organic solvent includes alcohol or ketone, and further, one of the first water insoluble organic solvent and the second water insoluble organic solvent includes any one of alcohol fluoride, hydrofluoroether (HFE), chlorofluorocarbon (CFC), hydrofluorocarbon (HFC), and perfluorocarbon. 
     
     
         25 . The supercritical drying method according to  claim 21 , wherein the first water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         26 . The supercritical drying method according to  claim 21 , wherein the second water, insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         27 . The supercritical drying method according to  claim 21 , wherein the water soluble organic solvent is isopropyl alcohol (IPA). 
     
     
         28 . A supercritical drying device comprising:
 a cleaning unit configured to clean a semiconductor substrate with a chemical solution;   a rinsing unit configured to rinse the semiconductor substrate with pure water to cover a surface of the semiconductor substrate after cleaning the semiconductor substrate;   a supplying unit configured to supply a water soluble organic solvent onto the semiconductor substrate after rinsing the semiconductor substrate, to replace the pure water covering the surface of the semiconductor substrate with the water soluble organic solvent;   a supplying unit configured to supply a first water insoluble organic solvent onto the semiconductor substrate after replacing the pure water;   a chamber;   an introducing unit configured to introduce the semiconductor substrate into the chamber, the surface of the semiconductor substrate being covered with the first water insoluble organic solvent;   a supplying unit configured to supply a second water insoluble organic solvent into the chamber;   a setting unit configured to set a temperature inside of the chamber at a critical temperature of the second water insoluble organic solvent or higher, to turn the second water insoluble organic solvent into a supercritical state; and   a decreasing unit configured to decrease a pressure inside of the chamber while keeping a temperature inside of the chamber at a predetermined value which is equal to or more than a boiling point of the water soluble organic solvent, to turn the second water insoluble organic solvent in the supercritical state into a gaseous state, thus discharging the second water soluble organic solvent from the chamber, after turning the second water insoluble organic solvent into the supercritical state.   
     
     
         29 . The supercritical drying device according to  claim 28 , wherein the predetermined value is a temperature at which the steam pressure of the water soluble organic solvent becomes higher than a critical pressure of the second water insoluble organic solvent. 
     
     
         30 . The supercritical drying device according to  claim 29 , wherein the steam pressure of the second water insoluble organic solvent is higher than that of the water soluble organic solvent. 
     
     
         31 . The supercritical drying device according to  claim 30 , wherein the water soluble organic solvent includes alcohol or ketone, and further, one of the first water insoluble organic solvent and the second water insoluble organic solvent includes any one of alcohol fluoride, hydrofluoroether (HFE), chlorofluorocarbon (CFC), hydrofluorocarbon (HFC), and perfluorocarbon. 
     
     
         32 . The supercritical drying device according to  claim 28 , wherein the first water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         33 . The supercritical drying device according to  claim 28 , wherein the second water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         34 . The supercritical drying device according to  claim 28 , wherein the predetermined value is equal to or more than 200° C. 
     
     
         35 . The supercritical drying device according to  claim 28 , wherein the water soluble organic solvent is isopropyl alcohol (IPA). 
     
     
         36 . A supercritical drying device comprising:
 a cleaning unit configured to clean a semiconductor substrate with a chemical solution;   a rinsing unit configured to rinse the semiconductor substrate with pure water to cover a surface of the semiconductor substrate after cleaning the semiconductor substrate;   a supplying unit configured to supply a water soluble organic solvent onto the semiconductor substrate after rinsing the semiconductor substrate, to replace the pure water covering the surface of the semiconductor substrate with the water soluble organic solvent;   a supplying unit configured to supply a first water insoluble organic solvent onto the semiconductor substrate after replacing the pure water;   a chamber:   an introducing unit configured to introduce the semiconductor substrate into the chamber, the surface of the semiconductor substrate being covered with the first water insoluble organic solvent;   a supplying unit configured to supply a second water insoluble organic solvent into the chamber;   a setting unit configured to set a temperature inside of the chamber at a critical temperature of the second water insoluble organic solvent or higher, to turn the second water insoluble organic solvent into a supercritical state; and   a decreasing unit configured to decrease a pressure inside of the chamber while keeping a temperature inside of the chamber at a predetermined value which is equal to or more than 200° C., to turn the second water insoluble organic solvent in the supercritical state into a gaseous state, thus discharging the second water soluble organic solvent from the chamber after turning the second water insoluble organic solvent into the supercritical state.   
     
     
         37 . The supercritical drying device according to  claim 36 , wherein the predetermined value is a temperature at which the steam pressure of the water soluble organic solvent becomes higher than a critical pressure of the second water insoluble organic solvent. 
     
     
         38 . The supercritical drying device according to  claim 37 , wherein the steam pressure of the second water insoluble organic solvent is higher than that of the water soluble organic solvent. 
     
     
         39 . The supercritical drying device according to  claim 38 , wherein the water soluble organic solvent includes alcohol or ketone, and further, one of the first water insoluble organic solvent and the second water insoluble organic solvent includes any one of alcohol fluoride, hydrofluoroether (HFE), chlorofluorocarbon (CFC), hydrofluorocarbon (HFC), and perfluorocarbon. 
     
     
         40 . The supercritical drying device according to  claim 36 , wherein the first water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         41 . The supercritical drying device according to  claim 36 , wherein the second water insoluble organic solvent is perfluorocarbon (PFC). 
     
     
         42 . The supercritical drying device according to  claim 36 , wherein the water soluble organic solvent is isopropyl alcohol (IPA).