JP6668166B2 - Fluorine-containing organic solvent recovery device and substrate processing device - Google Patents

Description

  The present embodiment relates to a recovery device used for removing a liquid attached to a surface of a substrate using a high-pressure fluid in a supercritical state or a subcritical state.

  In the process of manufacturing a semiconductor device in which a laminated structure of integrated circuits is formed on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as a wafer), a cleaning liquid such as a chemical solution removes minute dust and a natural oxide film on the wafer surface. And a liquid processing step of processing the wafer surface using the liquid.

However, with the high integration of semiconductor devices, when removing liquids and the like adhering to the wafer surface in such a liquid processing process, a supercritical method is used as a method of removing liquid adhering to the wafer surface while suppressing the occurrence of pattern collapse. A supercritical processing method using a fluid in a state or a subcritical state (hereinafter, these are collectively referred to as a high pressure state) is known.
For example, in Patent Document 1, from the viewpoint of the high degree of substitution between a liquid and a high-pressure fluid and the suppression of the introduction of moisture during liquid treatment, both a liquid for preventing drying and a high-pressure fluid contain a fluorine-containing organic solvent. In Example 1, HFE (HydroFluoro Ether) which is described as "fluorine compound" is used. Further, the fluorine-containing organic solvent is also suitable as a liquid for preventing drying in that it is flame-retardant.

  On the other hand, fluorine-containing organic solvents such as HFE, HFC (HydroFluoro Carbon), PFC (PerFluoro Carbon), and PFE (PerFluoro Ether) are more expensive than IPA (IsoPropyl Alcohol) and the like, and volatile loss during wafer transfer is reduced. This leads to increased operating costs. Therefore, if a fluorine-containing organic solvent used as a liquid for preventing drying or a high-pressure fluid can be recovered and used, the operating cost can be reduced, which is convenient.

JP 2011-187570 A

  In this embodiment, a recovery apparatus which can recover and use as much as possible the fluorine-containing organic solvent used for removing the liquid attached to the surface of the object to be processed, thereby reducing operating costs The purpose is to provide.

  The present embodiment contains a fluorine-containing organic solvent, a collection tank in which the fluorine-containing organic solvent is covered with an aqueous layer formed from water having a lower specific gravity than the fluorine-containing organic solvent, and A supply nozzle for supplying a fluorine-containing organic solvent, wherein the supply nozzle is configured such that the lower end thereof is always located in the aqueous layer above the interface, and the supply nozzle is arranged vertically in the recovery tank. An apparatus for recovering a fluorine-containing organic solvent, wherein the apparatus is movable, a float is provided on the water layer, and the supply nozzle is attached to the float and moves vertically.

  The present embodiment contains a fluorine-containing organic solvent, a collection tank in which the fluorine-containing organic solvent is covered with an aqueous layer formed from water having a lower specific gravity than the fluorine-containing organic solvent, and A supply nozzle for supplying a fluorine-containing organic solvent, a position of an interface between the fluorine-containing organic solvent and the aqueous layer is detected by an interface detection sensor, and the supply nozzle is based on information from the interface detection sensor. The lower end thereof is always located in the water layer above the interface, an additional recovery tank is connected to the recovery tank via a discharge pump, and based on information from the interface detection sensor, This is a fluorine-containing organic solvent recovery device that operates a discharge pump to guide the fluorine-containing organic solvent in the recovery tank to the additional recovery tank.

  According to the embodiment of the present invention, the fluorine-containing organic solvent used for removing the liquid attached to the surface of the object can be recovered as much as possible.

FIG. 1 is a cross-sectional plan view of the liquid processing apparatus. FIG. 2 is a vertical sectional side view of a liquid processing unit provided in the liquid processing apparatus. FIG. 3 is a configuration diagram of a supercritical processing unit provided in the liquid processing apparatus. FIG. 4 is an external perspective view of a processing container of the supercritical processing unit. FIG. 5 is a schematic system diagram showing a recovery device according to the present embodiment. FIG. 6 is a diagram showing an operation sequence according to the embodiment. FIG. 7 is a diagram showing details of a collection device according to the present embodiment. FIG. 8 is a view showing a modification of the collection device. FIG. 9 is a diagram showing another modified example of the collection device. FIG. 10 is a diagram showing a comparative example of the recovery device.

<Substrate processing equipment>
First, a description will be given of a substrate processing apparatus in which a separation and regeneration apparatus according to the present invention is incorporated.
As an example of the substrate processing apparatus, a liquid processing unit 2 that supplies various processing liquids to a wafer W (object to be processed) as a substrate to perform liquid processing, and a liquid processing unit 2 for preventing drying attached to the wafer W after the liquid processing. A liquid processing apparatus 1 including a supercritical processing unit 3 (high-pressure fluid processing unit) for removing a liquid by bringing it into contact with a supercritical fluid (high-pressure fluid) will be described.

  FIG. 1 is a cross-sectional plan view showing the overall configuration of the liquid processing apparatus 1, and the left side of the drawing is the front. In the liquid processing apparatus 1, the FOUP 100 is mounted on the mounting section 11, and a plurality of wafers W having a diameter of, for example, 300 mm stored in the FOUP 100 are transferred through the loading / unloading section 12 and the transfer section 13 to the subsequent liquid processing section. 14, is transferred to and from the supercritical processing unit 15 and sequentially carried into the liquid processing unit 2 and the supercritical processing unit 3 to perform liquid processing and processing for removing the liquid for preventing drying. In the figure, reference numeral 121 denotes a first transfer mechanism for transferring a wafer W between the FOUP 100 and the transfer unit 13, and 131, a wafer transferred between the loading / unloading unit 12, the liquid processing unit 14, and the supercritical processing unit 15. W is a transfer shelf that serves as a buffer on which the W is temporarily placed.

  The liquid processing unit 14 and the supercritical processing unit 15 are provided with a transfer space 162 for the wafer W extending in the front-rear direction from an opening between the transfer unit 13 and the transfer unit 13. In the liquid processing unit 14 provided on the left side of the transport space 162 when viewed from the front side, for example, four liquid processing units 2 are arranged along the transport space 162. On the other hand, in the supercritical processing section 15 provided on the right side of the transport space 162, for example, two supercritical processing units 3 are arranged along the transport space 162.

  The wafer W is transferred between the liquid processing unit 2, the supercritical processing unit 3, and the transfer unit 13 by the second transfer mechanism 161 arranged in the transfer space 162. The second transfer mechanism 161 corresponds to a substrate transfer unit. Here, the number of the liquid processing units 2 and the supercritical processing units 3 arranged in the liquid processing unit 14 and the supercritical processing unit 15 is determined by the number of wafers W processed per unit time, the liquid processing unit 2 and the supercritical processing unit. The optimal layout is selected according to the difference in the processing time in Step 3 and the number of the liquid processing units 2 and the supercritical processing units 3 arranged.

  The liquid processing unit 2 is configured as a single-wafer type liquid processing unit 2 for cleaning the wafers W one by one by, for example, spin cleaning, and as shown in a vertical side view of FIG. A wafer holding mechanism 23 disposed in the outer chamber 21 for rotating the wafer W about a vertical axis while holding the wafer W substantially horizontally; and a wafer holding mechanism 23 arranged so as to surround the wafer holding mechanism 23 from a peripheral side. An inner cup 22 for receiving liquid scattered from the nozzle W, and a nozzle arm 24 movably configured between a position above the wafer W and a position retracted from the wafer W, and a nozzle 241 provided at a tip end thereof. I have.

  The nozzle 241 includes a processing liquid supply unit 201 for supplying various chemicals, a rinsing liquid supply unit 202 for supplying a rinsing liquid, and a fluorine-containing organic solvent for pretreatment which is a liquid for preventing drying on the surface of the wafer W. A pretreatment fluorine-containing organic solvent supply section 203a (pretreatment organic solvent supply section) for supplying and a first fluorine-containing organic solvent supply section 203b (first first supply) for supplying a first fluorine-containing organic solvent. Organic solvent supply unit) is connected. The fluorine-containing organic solvent and the first fluorine-containing organic solvent for the pretreatment are different from the second fluorine-containing organic solvent used for the supercritical treatment described later, and the fluorine-containing organic solvent for the pretreatment is used. The solvent and the first fluorine-containing organic solvent and the second fluorine-containing organic solvent have a predetermined relationship in their boiling point and critical temperature, and the details thereof will be described later. I do.

  Alternatively, a chemical solution supply path 231 may be formed inside the wafer holding mechanism 23, and the back surface of the wafer W may be cleaned with the chemical solution and the rinsing liquid supplied from the chemical solution supply path 231. At the bottom of the outer chamber 21 and the inner cup 22, an exhaust port 212 for exhausting the internal atmosphere and drain ports 221 and 211 for discharging the liquid shaken off from the wafer W are provided.

  To the wafer W that has been subjected to the liquid processing in the liquid processing unit 2, a pretreatment fluorine-containing organic solvent and a first fluorine-containing organic solvent for drying prevention are supplied. Is transported to the supercritical processing unit 3 by the second transport mechanism 161 while being covered with the fluorine-containing organic solvent. In the supercritical processing unit 3, a process of bringing the wafer W into contact with the supercritical fluid of the second fluorine-containing organic solvent to remove the first fluorine-containing organic solvent and drying the wafer W is performed. Hereinafter, the configuration of the supercritical processing unit 3 will be described with reference to FIGS.

  The supercritical processing unit 3 includes a processing container 3A in which a process for removing a liquid (first fluorine-containing organic solvent) for preventing drying attached to the surface of the wafer W is performed, and a second fluorine-containing organic solvent is provided in the processing container 3A. And a supercritical fluid supply unit 4A (second organic solvent supply unit) for supplying a supercritical fluid of a solvent.

  As shown in FIG. 4, the processing container 3A includes a housing-shaped container main body 311 in which an opening 312 for loading / unloading the wafer W is formed, and a wafer tray 331 capable of holding the wafer W to be processed in a horizontal direction. And a lid member 332 that supports the wafer tray 331 and seals the opening 312 when the wafer W is carried into the container body 311.

  The container main body 311 is a container in which a processing space capable of accommodating, for example, a wafer W having a diameter of 300 mm is formed, and a supercritical fluid supply line 351 for supplying a supercritical fluid into the processing container 3A is provided on an upper surface thereof. And a discharge line 341 (discharge unit) provided with an on-off valve 342 for discharging the fluid in the processing container 3A. Further, the cover member 332 is pressed against the container body 311 against the internal pressure received from the high-pressure processing fluid supplied into the processing space into the processing container 3A, and an unillustrated pressing for sealing the processing space is performed. A mechanism is provided.

  The container main body 311 is provided with a heater 322 as a heating unit including, for example, a resistance heating element, and a temperature detecting unit 323 including a thermocouple for detecting the temperature in the processing container 3A. By heating the main body 311, the temperature in the processing container 3 </ b> A is heated to a preset temperature, and thereby, the wafer W inside can be heated. The heater 322 can change the amount of heat generated by changing the power supplied from the power supply unit 321, and presets the temperature in the processing container 3 </ b> A based on the temperature detection result obtained from the temperature detection unit 323. Adjust to the specified temperature.

  The supercritical fluid supply unit 4A is connected to an upstream side of a supercritical fluid supply line 351 provided with an on-off valve 352. The supercritical fluid supply unit 4A includes a spiral pipe 411 that is a pipe for preparing a supercritical fluid of the second fluorine-containing organic solvent to be supplied to the processing vessel 3A, and a spiral pipe 411 that is a raw material of the supercritical fluid in the spiral pipe 411. A second fluorine-containing organic solvent supply unit 414 for supplying a liquid of the second fluorine-containing organic solvent, and a halogen lamp for heating the spiral tube 411 to bring the second fluorine-containing organic solvent inside to a supercritical state. 413.

  The spiral tube 411 is, for example, a cylindrical container formed by spirally winding a stainless steel pipe member in the longitudinal direction, and is, for example, a black radiant heat absorbing paint for facilitating absorption of radiant heat supplied from the halogen lamp 413. Painted with. The halogen lamp 413 is arranged apart from the inner wall surface of the spiral tube 411 along the central axis of the cylinder. A power supply section 412 is connected to a lower end of the halogen lamp 413, and the halogen lamp 413 is heated by electric power supplied from the power supply section 412 and heats the spiral tube 411 mainly by using the radiant heat. The power supply unit 412 is connected to a temperature detection unit (not shown) provided in the spiral tube 411, and increases or decreases the power supplied to the spiral tube 411 based on the detected temperature, and adjusts the power of the spiral tube 411 to a preset temperature. Can be heated.

  A pipe member extends from the lower end of the spiral tube 411 to form a second fluorine-containing organic solvent receiving line 415. The receiving line 415 is connected to a second fluorine-containing organic solvent supply unit 414 via an open / close valve 416 having pressure resistance. The second fluorine-containing organic solvent supply unit 414 includes a tank for storing the second fluorine-containing organic solvent in a liquid state, a liquid feed pump, a flow control mechanism, and the like.

  The liquid processing apparatus 1 including the liquid processing unit 2 and the supercritical processing unit 3 having the above-described configuration is connected to the control unit 5 as shown in FIGS. The control unit 5 includes a computer having a CPU (not shown) and a storage unit 5a. The storage unit 5a operates the liquid processing apparatus 1, that is, takes out the wafer W from the FOUP 100 and performs liquid processing in the liquid processing unit 2. Next, a program in which a group of steps (instructions) related to an operation from a process of drying the wafer W in the supercritical processing unit 3 until the wafer W is loaded into the FOUP 100 is recorded. This program is stored in a storage medium such as a hard disk, a compact disk, a magnet optical disk, and a memory card, and is installed in the computer from there.

  Next, the pretreatment fluorine-containing organic solvent, the first fluorine-containing organic solvent, and the first fluorine-containing organic solvent supplied to the surface of the wafer W in the liquid processing unit 2 are removed from the surface of the wafer W. For this purpose, the second fluorine-containing organic solvent supplied to the processing container 31 in a supercritical fluid state will be described. Each of the pretreatment fluorine-containing organic solvent, the first fluorine-containing organic solvent, and the second fluorine-containing organic solvent is a fluorine-containing organic solvent containing a fluorine atom in a hydrocarbon molecule.

Table 1 shows examples of combinations of the pretreatment fluorine-containing organic solvent, the first fluorine-containing organic solvent, and the second fluorine-containing organic solvent.

  In the classification names in Table 1, HFE (HydroFluoro Ether) indicates a fluorine-containing organic solvent in which a part of hydrogen of a hydrocarbon having an ether bond in a molecule is replaced with fluorine, and HFC (HydroFluoro Carbon) is a hydrocarbon. Represents a fluorine-containing organic solvent in which a part of hydrogen is replaced by fluorine. In addition, PFC (PerFluoro Carbon) indicates a fluorine-containing organic solvent in which all hydrogens of a hydrocarbon are replaced by fluorine, and PFE (PerFluoro Ether) converts all hydrogens of a hydrocarbon having an ether bond in a molecule to fluorine. It is a substituted fluorine-containing organic solvent.

  When one of the fluorine-containing organic solvents is selected as the second fluorine-containing organic solvent, the first fluorine-containing organic solvent has a boiling point higher than that of the second fluorine-containing organic solvent. Higher (lower vapor pressure) is selected. Thereby, as compared with the case where the second fluorine-containing organic solvent is employed as the liquid for preventing drying, the evaporation from the surface of the wafer W during the transfer from the liquid processing unit 2 to the supercritical processing unit 3 is performed. The amount of the fluorine-containing organic solvent to be used can be reduced.

  More preferably, the boiling point of the first fluorine-containing organic solvent is preferably 100 ° C. or higher (for example, 174 ° C.). Since the first fluorine-containing organic solvent having a boiling point of 100 ° C. or more has a smaller volatilization amount during the transfer of the wafer W, for example, a wafer W having a diameter of 300 mm is about 0.01 to 5 cc, and a wafer W having a diameter of 450 mm is used. By supplying a small amount of a fluorine-containing organic solvent of about 0.02 to 10 cc, the surface of the wafer W can be kept wet for several tens of seconds to about 10 minutes. For reference, a supply amount of about 10 to 50 cc is required to keep the surface of the wafer W in a wet state for a similar time by IPA.

  When two types of fluorine-containing organic solvents are selected, the level of the boiling point corresponds to the level of the supercritical temperature. Therefore, by selecting a second fluorine-containing organic solvent having a lower boiling point than that of the first fluorine-containing organic solvent to be used as a supercritical fluid, it is possible to form a supercritical fluid at a low temperature. An organic solvent can be used, and the release of fluorine atoms due to the decomposition of the fluorine-containing organic solvent can be suppressed.

<Recovery device>
Next, a recovery apparatus according to the present embodiment, which is incorporated in a substrate processing apparatus, will be described with reference to FIG.

  As shown in FIGS. 5 to 7, the recovery device 30 includes a cooler 34 that cools the mixed gas generated in the supercritical processing unit 3 that performs the supercritical processing on the wafer W, and a recovery tank that stores the mixed gas. And a supply nozzle 37 for supplying the mixed gas cooled by the cooler 34 to the recovery tank 36.

  Among them, the mixed gas generated in the supercritical processing unit 3 includes air and the second fluorine-containing organic solvent, and further includes F ions mixed during the supercritical processing. The gas mixture from the supercritical processing unit 3 is sent to the cooler 34 via the introduction line 50. In the supercritical processing unit 3, supercritical processing is performed at, for example, a pressure of 20 atm, and the mixed gas in the supercritical processing unit 3 is depressurized by the orifice 54 and sent to the cooler 34. To the recovery tank 36 which is open to the atmosphere. A cooling water inlet pipe 34a and a cooling water outlet pipe 34b are connected to the cooler 34, and the gas mixture is cooled in the cooler 34 by the cooling water flowing through the cooling water inlet pipe 34a and the cooling water outlet pipe 34b. You.

  As described above, the mixed gas cooled in the cooler 34 is supplied into the collection tank 36 through the supply nozzle 37.

  A water layer 36a is accommodated in the recovery tank 36, and a mixed gas containing air and the second fluorine-containing organic solvent is sent into the recovery tank 36 through a supply nozzle 37, and cooled by the water layer 36a to form a second gas. Is liquefied and sent below the aqueous layer 36a.

  In this case, the lower end 37a of the supply nozzle 37 is located in the water tank 36a above the interface 38 between the water layer 36a and the second fluorine-containing organic solvent 52a in the recovery tank 36.

  Further, in the recovery tank 36, the liquid second fluorine-containing organic solvent 52a has a higher specific gravity than the water forming the water layer 36a, and is stored below the water layer 36a. Here, the water layer 36a is formed from water (DIW) having a lower specific gravity than the second fluorine-containing organic solvent 52a.

Next, the structure of the recovery tank 36 will be described in detail with reference to FIGS.
The cooler 34 and the supply nozzle 37 are connected by a flexible tube 37b, and the supply nozzle 37 in the recovery tank 36 can move in the vertical direction.

  A float 39 is arranged on the water layer 36a made of water (DIW), and the supply nozzle 37 is fixed to the float 39. The float 39 moves up and down in response to the fluctuation of the water level on the surface of the water layer 36a, and the supply nozzle 37 fixed to the float 39 also moves up and down.

  The thickness of the water layer 36a generally made of water is regularly supplied from a water supply unit (not shown) and is kept constant, so that the float 39 has a function of detecting the water level on the surface of the water layer 36a, It also has a function of detecting the position of the interface 38 between the water layer 36a and the second fluorine-containing organic solvent 52a (function as an interface detection sensor).

  The supply nozzle 37 is fixed to the float 39 at such a position that the lower end 37a of the supply nozzle 37 is always located in the water layer 36a.

  When the float 39 and the supply nozzle 37 move in the vertical direction in the collection tank 36, the vertical movement of the supply nozzle 37 is absorbed by the flexible tube 37b provided on the upstream side of the supply nozzle 37.

Next, as shown in FIG. 5, the second fluorine-containing organic solvent 52a in the recovery tank 36 is sent to the oil-water separator 41. The second fluorine-containing organic solvent sent to the oil-water separator 41 may contain water mixed with F ions, and the water mixed with the F ions becomes second oil-containing water in the oil-water separator 41. Separated from organic solvents.
The water mixed with F ions in the oil-water separator 41 is then discharged outward.

  The second fluorine-containing organic solvent from which the water containing the F ions has been separated by the oil-water separator 41 is then sent to the supply tank 45 via the supply line 42.

  An organic substance removing filter 40a containing activated carbon, an ion removing filter 42b containing activated alumina, and a particle removing filter 40c are sequentially attached to the supply line 42.

  Further, the second fluorine-containing organic solvent in the supply tank 45 is returned to the supercritical processing unit 3 as a FC72 regenerating liquid via the supply line 46 to which the pump 46a is attached.

  The supply line 46 is provided with a densitometer 62 for measuring the concentration of the second fluorine-containing organic solvent. As the densitometer 62, a hydrometer for measuring a change in specific gravity corresponding to a change in density, or an optical measuring device for measuring a change in refractive index corresponding to a change in density can be used.

  The components of the recovery device 30, for example, the pump 46a and the like are driven and controlled by the control unit 5 having the storage unit 5a.

<Operation of the present embodiment>
Next, the operation of the present embodiment having such a configuration will be described.
In the present embodiment, the operation when HFE7300 is used as the fluorine-containing organic solvent for pretreatment, FC43 is used as the first fluorine-containing organic solvent, and FC72 is used as the second fluorine-containing organic solvent will be described. .

  First, the wafer W taken out of the FOUP 100 is loaded into the liquid processing unit 14 via the loading / unloading unit 12 and the transfer unit 13, and is transferred to the wafer holding mechanism 23 of the liquid processing unit 2. Next, various processing liquids are supplied to the surface of the rotating wafer W to perform liquid processing.

  As shown in FIG. 6, in the liquid treatment, for example, removal of particles and organic contaminants by SC1 liquid (a mixture of ammonia and hydrogen peroxide solution) which is an alkaline chemical liquid → deionized water (DeIonized) which is a rinse liquid Rinse cleaning with Water: DIW) is performed.

  After the liquid treatment with the chemical solution and the rinsing cleaning are completed, IPA is supplied from the rinsing supply unit 202 to the front surface of the rotating wafer W to replace the DIW remaining on the front and back surfaces of the wafer W. When the liquid on the surface of the wafer W is sufficiently replaced with IPA, the fluorine-containing organic solvent (HFE7300) for pretreatment is supplied to the surface of the rotating wafer W from the fluorine-containing organic solvent supply unit 203a for pretreatment. The rotation of the wafer W is stopped. The surface of the wafer W after the rotation is stopped is covered with the first fluorine-containing organic solvent. In this case, since IPA has high harmony with DIW and HFE7300, and HFE7300 has high harmony with IPA and FC43, DIW can be reliably replaced with IPA, and then IPA can be reliably replaced with HFE7300. be able to. Next, HFE7300 can be easily and reliably replaced by FC43.

  The wafer W after the liquid processing is carried out of the liquid processing unit 2 by the second transfer mechanism 161 and transferred to the supercritical processing unit 3. Since a fluorine-containing organic solvent having a high boiling point (low vapor pressure) is used as the first fluorine-containing organic solvent, the amount of the fluorine-containing organic solvent volatilized from the surface of the wafer W during the transfer period is reduced. can do.

  At a timing before the wafer W is loaded into the processing container 3A, the supercritical fluid supply unit 4A opens the on-off valve 416 to supply the liquid of the second fluorine-containing organic solvent from the second fluorine-containing organic solvent supply unit 414. After supplying a predetermined amount of liquid, the on-off valves 352 and 416 are closed, and the spiral tube 411 is sealed. At this time, the liquid of the second fluorine-containing organic solvent is accumulated below the spiral tube 411, and the second fluorine-containing organic solvent evaporated above the spiral tube 411 when the second fluorine-containing organic solvent is heated. A space where the contained organic solvent expands is left.

  Then, power supply from the power supply unit 412 to the halogen lamp 413 is started, and when the halogen lamp 413 generates heat, the inside of the spiral tube 411 is heated, the second fluorine-containing organic solvent is evaporated, and the temperature is increased and the pressure is increased. It reaches temperature and critical pressure and becomes a supercritical fluid. When the second fluorine-containing organic solvent in the spiral tube 411 is supplied to the processing container 3A, the temperature is increased and raised to a critical pressure and a temperature at which the critical temperature can be maintained.

  The liquid processing is completed, and the wafer W whose surface is covered with the first fluorine-containing organic solvent is carried into the supercritical processing unit 3 ready to supply the supercritical fluid of the second fluorine-containing organic solvent. Come.

  When the wafer W is loaded into the processing container 3A and the lid member 332 is closed and closed, the on-off valve of the supercritical fluid supply line 351 is dried before the first fluorine-containing organic solvent on the surface of the wafer W is dried. By opening 352, the supercritical fluid of the second fluorine-containing organic solvent is supplied from the supercritical fluid supply unit 41.

  When the supercritical fluid is supplied from the supercritical fluid supply unit 41 and the inside of the processing vessel 3A becomes a supercritical fluid atmosphere of the second fluorine-containing organic solvent, the on-off valve 352 of the supercritical fluid supply line 351 is closed. The supercritical fluid supply unit 4A turns off the halogen lamp 413, discharges the fluid in the spiral tube 411 through a depressurizing line (not shown), and prepares a second fluorine-containing organic solvent to prepare the next supercritical fluid. The system is ready to receive the liquid second fluorine-containing organic solvent from the supply unit 414.

  On the other hand, the supply of the supercritical fluid from the outside to the processing container 3A is stopped, and the inside of the processing container 3A is filled with the supercritical fluid of the second fluorine-containing organic solvent and is in a sealed state. At this time, focusing on the surface of the wafer W in the processing container 3A, the supercritical fluid of the second fluorine-containing organic solvent is in contact with the liquid of the first fluorine-containing organic solvent that has entered the pattern.

  When the liquid of the first fluorine-containing organic solvent and the supercritical fluid are kept in contact with each other, the first and second fluorine-containing organic solvents that are easily mixed with each other are mixed, and the liquid in the pattern is removed. Replaced by supercritical fluid. Eventually, the liquid of the first fluorine-containing organic solvent is removed from the surface of the wafer W, and an atmosphere of a supercritical fluid of a mixture of the first fluorine-containing organic solvent and the second fluorine-containing organic solvent is formed around the pattern. It is formed. At this time, since the liquid of the first fluorine-containing organic solvent can be removed at a relatively low temperature close to the critical temperature of the second fluorine-containing organic solvent, the fluorine-containing organic solvent hardly decomposes and damages the pattern and the like. The amount of generated hydrogen fluoride is also small.

  After the time required for removing the liquid of the second fluorine-containing organic solvent from the surface of the wafer W elapses, the on-off valve 342 of the discharge line 341 is opened to discharge the fluorine-containing organic solvent from the processing chamber 3A. I do. At this time, for example, the amount of heat supplied from the heater 322 is adjusted so that the inside of the processing container 3A is maintained at or above the critical temperature of the second fluorine-containing organic solvent. As a result, the mixed fluid can be discharged in a supercritical state or a gaseous state without liquefying the first fluorine-containing organic solvent having a boiling point lower than the critical temperature of the second fluorine-containing organic solvent. The occurrence of pattern collapse can be avoided.

  After the processing with the supercritical fluid is completed, the wafer W from which the liquid has been removed and dried is taken out by the second transfer mechanism 161, conveyed along the path opposite to that at the time of loading, stored in the FOUP 100, and a series of Finish the process. In the liquid processing apparatus 1, the above-described processing is continuously performed on each wafer W in the FOUP 100.

  During this time, mixed exhaust gas is generated during the supercritical processing in the supercritical processing unit 3, and the mixed exhaust gas in the supercritical processing unit 3 is sent into the cooler 34 through the introduction line 50 and cooled by the cooler 34. Then, it is sent from the cooler 34 to the collection tank 36 via the flexible tube 37b and the supply nozzle 37.

  In this case, the pressure in the supercritical processing unit 3 is 20 atm, and the mixed exhaust gas from the supercritical processing unit 3 is reduced in pressure by the orifice 54 to 1 atm and passes through the cooler 34 and the flexible tube 37b. The water is sent from the lower end 37 a of the supply nozzle 37 into the water layer 36 a of the collection tank 36.

  The mixed gas generated in the supercritical processing unit 3 and sent to the recovery tank 36 contains FC72 of the second fluorine-containing organic solvent (boiling point 56 ° C.) and air.

  As shown in FIG. 7, the gas mixture supplied to the recovery tank 36 is sent from the lower end 37 a thereof into the water layer 36 a via the supply nozzle 37. In this case, the second fluorine-containing organic solvent in the mixed gas is cooled and liquefied by the water layer 36a, and is sent into the liquid second fluorine-containing organic solvent 52a located below the water layer 36a of the recovery tank 36. Can be Further, F ions in the mixed gas are removed by the water layer 36a.

  In this manner, the second fluorine-containing organic solvent in the mixed gas sent to the collection tank 36 is cooled and liquefied by the water layer 36a, and can be reliably recovered as a liquid second fluorine-containing organic solvent. .

  Next, FIG. 10 shows a comparative example of the present case. In FIG. 10, when the supply nozzle 37 of the collection device 30 is fixed in the collection tank 36, the lower end 37 a of the supply nozzle 37 is set to the second liquid state as the liquid second fluorine-containing organic solvent 52 a increases. Contact with the fluorine-containing organic solvent 52a.

In this case, the air in the mixed gas or the second fluorine-containing organic solvent dissolved in N ₂ is released as bubbles into the liquid second fluorine-containing organic solvent 52a onto the water layer 36a, or It is also conceivable that the second fluorine-containing organic solvent in the form of a bubble entrains the second fluorine-containing organic solvent 52a in the liquid state and is released onto the water layer 36a together.

  When the second fluorine-containing organic solvent is discharged above the water layer 36a in the recovery tank 36, the recovery rate of the liquid second fluorine-containing organic solvent recovered by the recovery tank 36 decreases. Resulting in.

  On the other hand, according to the present embodiment, since the lower end of the supply nozzle 37 can always be arranged in the water layer 36a, the second fluorine-containing organic solvent in the mixed gas sent to the collection tank 36 is replaced with water. The liquid is cooled and liquefied by the layer 36a, and can be reliably recovered as the liquid second fluorine-containing organic solvent.

  During this time, the organic matter in the recovery tank 36 is discharged outward as organic exhaust from above the recovery tank 36.

  Thus, the liquid second fluorine-containing organic solvent 52a is stored below the water layer 36a in the recovery tank 36, and the second fluorine-containing organic solvent in the recovery tank 36 is supplied to the second oil-water separator. It is sent to 41.

The second fluorine-containing organic solvent sent to the oil-water separator 41 may contain water mixed with F ions, and the water mixed with the F ions is supplied to the second fluorine-containing organic solvent in the oil-water separator 41. Separated from contained organic solvents.
The water mixed with F ions in the oil-water separator 41 is then discharged outward.

  The second fluorine-containing organic solvent from which the water containing the F ions has been separated by the second oil-water separator 41 is then sent to the supply tank 45 via the supply line 42.

  Next, the second fluorine-containing organic solvent in the supply tank 45 is returned into the supercritical processing unit 3 as the FC72 regenerating liquid via the supply line 46 to which the pump 46a is attached.

<Modification>
Next, a modification of the collection device 30 will be described with reference to FIGS.
In the modification shown in FIG. 8, a supply nozzle 37 installed in a recovery tank 36 of an open-to-atmosphere type is fixed to the recovery tank 36, and a water layer 36a and a second fluorine-containing An interface sensor 70 comprising a float sensor for detecting an interface 38 between the organic solvent 52a and the organic solvent 52a is provided, and other configurations are substantially the same as those of the embodiment shown in FIGS.

  8, the lower end 37a of the supply nozzle 37 is located in the water layer 36a in the recovery tank 37.

  Further, below the collection tank 36, a closed additional collection tank 71 is connected via a discharge line 73 having a discharge pump 72, and the discharge pump 72 controls the control unit 5 (based on information from the interface detection sensor 70). (See FIG. 1).

  In FIG. 7, the gas mixture generated in the supercritical processing unit 3 is cooled by the cooler 34 and sent to the recovery tank 36 via the supply nozzle 37. In this case, the mixed gas contains FC72, which is the second organic solvent containing fluorine (boiling point: 56 ° C.), and air.

  The mixed gas supplied to the recovery tank 36 is sent from the lower end 37a of the supply nozzle 37 into the water layer 36a. In this case, the second fluorine-containing organic solvent in the mixed gas is cooled and liquefied by the water layer 36a, and is sent into the liquid second fluorine-containing organic solvent 52a located below the water layer 36a of the recovery tank 36. Can be Further, F ions in the mixed gas are removed by the water layer 36a.

  In this manner, the second fluorine-containing organic solvent in the mixed gas sent to the collection tank 36 is cooled and liquefied by the water layer 36a, and can be reliably recovered as a liquid second fluorine-containing organic solvent. .

  During this time, when the amount of the liquid second fluorine-containing organic solvent 52a in the recovery tank 36 increases, the interface 38 between the water layer 36a and the second fluorine-containing organic solvent 52a rises. In this case, the rise of the interface 38 is detected by the interface detection sensor 70, and based on the information from the interface detection sensor 70, the control unit 5 operates the discharge pump 72, and the liquid second fluorine-containing liquid in the recovery tank 36. The organic solvent 52a is guided to the closed type additional recovery tank 71. Thus, the interface 38 between the water layer 36a and the second fluorine-containing organic solvent 52a can be kept at a fixed position. Therefore, in the recovery tank 36, the lower end 37a of the supply nozzle 37 is maintained in the water layer 36, and the lower end of the supply nozzle 37 does not come into contact with the second fluorine-containing organic solvent 52a.

  Next, the second fluorine-containing organic solvent 52a sent to the additional recovery tank 71 is sent to the oil-water separator 41.

Next, a further modification of the collection device 30 will be described with reference to FIG.
In the modification shown in FIG. 9, a closed-type recovery tank 36 is provided instead of the open-to-atmosphere type recovery tank 36, and the excess pressure release in the recovery tank 36 is provided above the closed-type recovery tank 36. A surplus pressure release line 77 is provided.

  The surplus pressure release line 77 has a U-shaped portion 77b, and a water layer 77a is accommodated in the U-shaped portion 77b. In addition, a liquid second fluorine-containing organic solvent 52a is stored in the recovery tank 36, but there is no aqueous layer.

  In the modification shown in FIG. 9, the other configuration is substantially the same as the embodiment shown in FIGS.

  In FIG. 9, the gas mixture generated in the supercritical processing unit 3 is cooled by the cooler 34 and sent to the recovery tank 36 via the supply nozzle 37. In this case, the mixed gas contains FC72, which is the second organic solvent containing fluorine (boiling point: 56 ° C.), and air.

  Next, the mixed gas supplied to the recovery tank 36 is sent from the lower end 37a of the supply nozzle 37 into the liquid second fluorine-containing organic solvent 52a. In this case, the second fluorine-containing organic solvent in the mixed gas is cooled and liquefied, and merges with the liquid second fluorine-containing organic solvent 52a in the recovery tank 36.

  On the other hand, it is conceivable that the second fluorine-containing organic solvent in the recovery tank 36 becomes gas and is discharged from the recovery tank 36 to the outside from the excess pressure release line 77. The second fluorine-containing organic solvent is prevented from being released outward by the water layer 77a contained in the U-shaped portion 77b.

  Therefore, the second fluorine-containing organic solvent in the recovery tank 36 is not released to the outside, and the recovery rate of the second fluorine-containing organic solvent does not decrease.

W Wafer 1 Liquid processing unit 2 Liquid processing unit 3 Supercritical processing unit (mixed gas generation unit)
3A Processing container 4A Supercritical fluid supply unit 5 Control unit 30 Separation / regeneration device 34 Cooler 36 Recovery tank 36a Water layer 37 Supply nozzle 37a Lower end 37b Flexible tube 38 Interface 39 Float 52a Liquid second fluorine-containing organic solvent 70 Interface detection sensor 71 Additional collection tank 72 Discharge pump 73 Discharge line

Claims (3)

A recovery tank containing the fluorine-containing organic solvent and covering the fluorine-containing organic solvent with an aqueous layer formed from water having a lower specific gravity than the fluorine-containing organic solvent,
A supply nozzle for supplying the fluorine-containing organic solvent in the collection tank,
The supply nozzle is configured such that its lower end is always located in the aqueous layer above the interface between the fluorine-containing organic solvent and the aqueous layer, and the supply nozzle moves vertically in the recovery tank. It is possible,
A float is provided on the water layer, the supply nozzle is attached to the float , a flexible tube is connected to the upstream side of the supply nozzle, and the flexible tube is moved in accordance with the vertical movement of the float. The supply nozzle moves in the vertical direction while maintaining its posture, thereby recovering the fluorine-containing organic solvent. A recovery tank containing the fluorine-containing organic solvent and covering the fluorine-containing organic solvent with an aqueous layer formed from water having a lower specific gravity than the fluorine-containing organic solvent,
A supply nozzle for supplying the fluorine-containing organic solvent into the collection tank ,
A cooler provided upstream of the supply nozzle and pre-cooling the fluorine-containing organic solvent supplied to the recovery tank,
The position of the interface between the fluorine-containing organic solvent and the aqueous layer is detected by an interface detection sensor, and the supply nozzle is configured such that the lower end of the water is always higher than the interface based on information from the interface detection sensor. Configured to be located in a layer,
An additional recovery tank is connected to the recovery tank via a discharge pump, and based on information from the interface detection sensor, the discharge pump is operated to transfer the fluorine-containing organic solvent in the recovery tank to the additional recovery tank. Leading device for recovery of fluorine-containing organic solvent. A liquid processing unit that performs liquid processing by supplying a fluorine-containing organic solvent to the object to be processed,
A supercritical processing unit that removes the liquid of the fluorine-containing organic solvent adhering to the object after the liquid treatment by contacting the liquid with the supercritical fluid of the fluorine-containing organic solvent,
A substrate transport unit that transports the object to be processed that has been subjected to the liquid processing in the liquid processing unit to the supercritical processing unit,
3. A substrate processing apparatus, wherein the apparatus for recovering a fluorine-containing organic solvent according to claim 1 or 2 is incorporated in the supercritical processing unit.

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