JP5522124B2 - Substrate processing apparatus, substrate processing method, and storage medium - Google Patents

Description

  The present invention relates to a technique for removing a liquid adhering to a surface of a substrate by bringing a high-pressure fluid into contact therewith.

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

  However, with the high integration of semiconductor devices, a phenomenon called so-called pattern collapse has become a problem when removing liquid adhering to the wafer surface in such a liquid processing step. For example, when the liquid that remains on the wafer surface is dried, the liquid that remains on the left and right of the projections and recesses that form the pattern is dried unevenly, for example, and the surface that pulls the projections to the left and right. This is a phenomenon in which the balance of tension collapses and the convex part falls down in the direction in which a large amount of liquid remains.

  As a method for removing the liquid adhering to the wafer surface while suppressing the occurrence of such pattern collapse, a method using supercritical and subcritical fluids (in the description of the background art, these are collectively referred to as supercritical fluids) is known. ing. The supercritical fluid has a smaller viscosity than the liquid and has a high ability to extract the liquid, and there is no interface between the supercritical fluid and the liquid or gas in an equilibrium state. Therefore, after the liquid adhering to the wafer surface is dissolved or replaced in the supercritical fluid, the state of the supercritical fluid is changed to a gas, so that the liquid can be dried without being affected by the surface tension.

  The inventors have developed and commercialized a technique for removing the liquid on the wafer surface using such a supercritical fluid. In the course of this development experiment, after performing an experiment to remove the liquid on the wafer surface using a supercritical fluid in a pre-cleaned processing container, the same processing is performed on another wafer in the same processing container. In addition, a phenomenon was observed in which more particles adhered to the second and subsequent wafers than in the first wafer.

  Here, in Patent Document 1, the rinse liquid adhering to the pattern formed on the substrate is replaced with liquid carbon dioxide, and the carbon dioxide is heated to a supercritical state and then vaporized, and then the substrate is dried. A method is described. However, the patent document 1 does not mention that the above-mentioned particle adhesion phenomenon has been found, and does not describe a solution.

  In addition, as described in Patent Document 1 described above, after finishing the process of removing the liquid adhering to the substrate, a pipe (supply pipe) for supplying liquid carbon dioxide to the reaction chamber (processing vessel) In general, an operation of lowering the pressure in the reaction chamber by closing the valve of) and then opening the valve on the outlet side is adopted. In this case, liquid carbon dioxide remains in the pipe upstream of the supply side valve.

JP 2004-1558591 A: Paragraphs 0029, 0039 to 0040, FIGS.

  The present invention has been made under such a background, and in the process of removing the liquid adhering to the substrate by being brought into contact with the high-pressure fluid, the substrate processing apparatus and substrate processing in which particles are less likely to adhere to the substrate. It is an object to provide a method and a storage medium storing the method.

A substrate processing apparatus according to the present invention includes a processing container in which a high-pressure fluid is brought into contact with a liquid for preventing drying on the surface of a substrate to perform a process for removing the liquid for preventing drying,
A fluid supply source for supplying the high-pressure fluid or a raw material fluid of the high-pressure fluid at a pressure higher than atmospheric pressure;
A fluid supply path connecting the fluid supply source and the processing container;
A flow rate adjusting unit and an on-off valve provided in this order from the upstream side in the fluid supply path;
A shut-off unit provided on the upstream side of the flow rate adjustment unit in the fluid supply path, or also serving as a flow rate adjustment unit;
A pressure reducing valve for reducing the pressure in the processing container, and a discharge path for discharging the fluid in the processing container;
Open the shut-off unit and open the on-off valve with the flow rate adjusted by the flow rate adjustment unit to introduce a high-pressure fluid into the processing vessel, or introduce the raw material fluid to change into a high-pressure fluid, and dry from the surface of the substrate. Removing the liquid for prevention, and then reducing the pressure inside the fluid supply path and the processing container by bringing the shut-off portion into a shut-off state and opening the on-off valve and the pressure reducing valve. And a controller that outputs a control signal so as to execute the step of unloading the substrate from the processing container and then closing the on-off valve .

Further, a substrate processing apparatus according to another invention includes a processing container in which a high-pressure fluid is brought into contact with a liquid for preventing drying on the surface of the substrate to remove the liquid for preventing drying,
A fluid supply source for supplying the high-pressure fluid or a raw material fluid of the high-pressure fluid at a pressure higher than atmospheric pressure;
A fluid supply path connecting the fluid supply source and the processing container;
A flow rate adjusting unit and an on-off valve provided in this order from the upstream side in the fluid supply path;
A shut-off unit provided on the upstream side of the flow adjustment unit in the fluid supply path, or also serving as a flow rate adjustment unit;
A branch path provided with a first pressure reducing valve for branching from the fluid supply path between the shut-off portion and the on-off valve and discharging and depressurizing the fluid in the fluid supply path;
A second pressure reducing valve for reducing the pressure in the processing container, and a discharge path for discharging the fluid in the processing container;
While closing the first pressure reducing valve, the shut-off unit is opened, the flow rate is adjusted by the flow rate adjusting unit, the open / close valve is opened to introduce a high-pressure fluid into the processing vessel, or the raw material fluid is introduced to increase the pressure A step of removing the liquid for preventing drying from the surface of the substrate by changing to a fluid; and then, the shut-off portion is shut off and the on-off valve is closed, while the second pressure reducing valve is opened. Reducing the pressure inside the processing container; and after the shut-off section is shut off and the on-off valve is closed, the first pressure reducing valve is opened to allow the fluid remaining in the fluid supply path to flow from the branch path. And a control unit that outputs a control signal so as to execute the discharging step.

Each substrate processing apparatus described above may have the following features.
(A) The high-pressure fluid is a fluid in a supercritical state or a subcritical state, and the processing vessel is supplied with a high-pressure fluid from the fluid supply source, or the raw material fluid is heated in the processing vessel. Then, the liquid for preventing drying is extracted into the high-pressure fluid and removed from the surface of the substrate.
(B) The processing container includes a heating unit for heating a liquid for preventing drying on the surface of the substrate, and the high-pressure fluid heats the liquid for preventing drying to be in a supercritical state or a subcritical state. A fluid for pressurization to prevent vaporization of the anti-drying liquid, and the anti-drying liquid is in a pressurized atmosphere in contact with the high-pressure fluid. It is heated by the heating unit and removed from the surface of the substrate by directly changing from a liquid to a supercritical state or a subcritical state.
(C) A process for removing the drying preventing liquid from the substrate on which the pattern having a line width of 20 nm or less is formed.
(D) The pressure in the processing container when performing the process of removing the liquid for preventing drying from the substrate is 5 MPa or more, and the pressure in the processing container is reduced to atmospheric pressure.

  The present invention relates to a processing container in which a high-pressure fluid is brought into contact with a liquid adhering to a substrate and the processing for removing the liquid is finished, and a fluid supply for supplying the high-pressure fluid and the like to the processing container. Since the passage is decompressed together, the fluid remaining in the fluid supply path can be discharged to the outside via the processing container without generating a sudden pressure difference between the fluid supply path and the processing container. As a result, the pressure drop width when the fluid remaining in the fluid supply path flows into the processing container can be reduced, and the occurrence of contamination inside the processing container due to the density reduction of the fluid can be suppressed.

  In another aspect of the invention, a high pressure fluid is brought into contact with the liquid attached to the substrate, and the high pressure fluid is discharged to the processing container separately from the discharge path for discharging the fluid from the processing container that has performed the processing for removing the liquid. A branch path branched from a fluid supply path for supplying fluid or the like is provided. As a result, since the fluid remaining in the fluid supply path can be discharged without going through the processing container, it is possible to suppress the occurrence of contamination due to density reduction when the fluid flows into the processing container.

It is a cross-sectional top view of a washing | cleaning processing system. It is an external appearance perspective view of the said washing | cleaning processing system. It is a vertical side view of the washing | cleaning apparatus provided in the said washing | cleaning processing system. It is a block diagram of the supercritical processing apparatus concerning embodiment. It is an external appearance perspective view of the processing container of the supercritical processing apparatus. It is a 1st explanatory view showing an operation of the supercritical processing device. It is the 2nd explanatory view showing an operation of the supercritical processing device. It is the 3rd explanatory view showing an operation of the supercritical processing device. It is a 4th explanatory view showing an operation of the supercritical processing device. It is 5th explanatory drawing which shows the effect | action of the said supercritical processing apparatus. It is 1st explanatory drawing which shows the effect | action of the supercritical processing apparatus concerning other embodiment. It is the 2nd explanatory view showing an operation of the other supercritical processing device. It is 3rd explanatory drawing which shows the effect | action of the said other supercritical processing apparatus. It is the 4th explanatory view showing an operation of the other supercritical processing equipment. It is a 5th explanatory view showing an operation of the other supercritical processing device. It is explanatory drawing which shows the result of an Example. It is explanatory drawing which shows the result of a comparative example. It is the 1st explanatory view showing the conventional method of the operation which discharges the fluid after processing from a supercritical processing device. It is the 2nd explanatory view showing the conventional method of the operation which discharges the fluid after the processing.

Before describing a specific configuration of a supercritical processing apparatus as an embodiment of a substrate processing apparatus according to the present invention, the cause of the phenomenon of particle adhesion to a wafer described in the background art will be described. For example, a supercritical processing apparatus that uses carbon dioxide (CO ₂ : critical temperature 31 ° C., critical pressure (absolute pressure) 7.4 MPa) as a high-pressure fluid to remove CO ₂ in a supercritical state by contacting with the liquid on the surface of the wafer W. Think.

For example, FIGS. 18 and 19 show the conventional operation of the supercritical processing apparatus when the high-pressure fluid (supercritical CO ₂ ) is discharged after the process of removing the liquid adhering to the wafer W is finished. In the figure, 31 is a processing container for performing processing for removing liquid from the wafer W, 37 is a fluid supply source for supplying supercritical CO ₂ to the processing container 31, and 351 is supercritical CO supplied from the fluid supply source 37. ₂ is a fluid supply line (fluid supply path) for sending ₂ to the processing container 31, and 341 is a discharge line (discharge path) for discharging supercritical CO ₂ in the processing container 31.

The fluid supply line 351 includes a flow rate adjustment valve 354 that is a flow rate adjustment unit that adjusts the supply amount of supercritical CO ₂ , a filter 353 for removing particles contained in the fluid supply source 37, and a fluid supply source 37. An on-off valve 352 for introducing the supercritical CO ₂ supplied from the process vessel 31 into the processing vessel 31 and stopping it is provided in this order from the upstream side. Here, 342 interposed in the discharge line 341 reduces the pressure of the processing container 31 and adjusts the opening degree based on a detection value of a pressure gauge (described later) provided in the processing container 31, so that the inside of the processing container 31 This is a pressure reducing valve having a function of adjusting the pressure.

In this supercritical processing apparatus, after supercritical CO ₂ is brought into contact with the liquid on the surface of the wafer W and the processing for removing the liquid is finished, the flow rate adjustment valve 354 and the on-off valve 352 of the fluid supply line 351 are closed to close the supercriticality. After the supply of CO ₂ is stopped, CO ₂ is discharged, the inside of the processing container 31 is decompressed, and preparations for taking out the wafer W are made (FIG. 18).

At this time, the inside of the pipe of the fluid supply line 351 is a high-pressure atmosphere filled with supercritical CO ₂ . However, when the on-off valve 352 is opened to start the next process while the fluid supply line 351 is kept in a high-pressure atmosphere, the supercritical CO ₂ remaining in the pipe is adjusted by the flow rate control valve 354. It will flow rapidly into the processing container 31 without being carried out. As a result, the position of the wafer W in the processing container 31 may be displaced or the wafer W may be damaged. Therefore, it is necessary to discharge the supercritical CO _{2 in the} fluid supply line 351 after the processing. There is.

For these reasons, the atmosphere is also released from the fluid supply line 351 until the next wafer W is loaded into the processing container 31. At this time, as shown in FIG. 19, by opening the opening / closing valve 352 of the fluid supply line 351 and the pressure reducing valve 342 of the discharge line 341, CO ₂ in the fluid supply line 351 is externally passed through the processing container 31 and the discharge line 341. To be discharged.

  As described in the background art, after the wafer W is processed in the cleaned processing container 31, the above operation is performed to process the second wafer W, so that more particles than the first wafer are processed. The phenomenon of adhering is observed.

As shown in FIGS. 18 and 19, the fluid supply line 351 of the supercritical processing apparatus is provided with a filter 353, and the particles contained in the raw material in the fluid supply source 37 are removed in advance and then transferred to the processing container 31. The composition of particles adhering to the wafer W was analyzed in order to investigate the cause of the phenomenon of particle adhesion despite being supplied. According to the results of analysis, when a commercially available CO ₂ cylinder was used as the fluid supply source, one of the generation sources of the particles was water and oil contained in the raw material CO ₂ .

From these facts, the inventors, after the moisture and oil content held in the raw material CO ₂ in a fluid state pass through the filter 353, become mist in the processing container 31 for some reason and adhere to the wafer W. I thought that. In addition, since many particles adhere to the wafer W processed from the first to the second and subsequent wafers, mist formation of these moisture and oil is performed after the processing of the first wafer W is taken out. It was estimated that it occurred before starting the processing of the eye wafer W.

Furthermore, the inventors paid attention to the relationship between the density of CO ₂ as a high-pressure fluid and the ability to retain moisture and oil. In general, the higher the density of a fluid, the easier it is to hold the causative substances of these particles, and the holding capacity decreases in the order of “liquid> supercritical fluid> high pressure gas> atmospheric pressure gas”.

For this reason, in the region where the density of the high-pressure fluid (liquid CO ₂ , supercritical CO ₂ , high-pressure gas CO ₂ ) suddenly decreases to atmospheric pressure, the amount of water or oil that can be held in CO ₂ decreases. These substances can be expected to become mist. Therefore, when the inside of the discharge line 341 on the downstream side of the pressure reducing valve 342 in which the supercritical CO ₂ is rapidly depressurized in the operation of releasing the processing container 31 shown in FIG. 18 is observed, a large amount of the inside of the pipe is also observed. Particles were adhered, and these compositions were also water and oil contained in the raw material CO ₂ . Here, the inventors have grasped that the generation amount of such particles becomes remarkable when there is a large pressure difference such as reducing the pressure of the fluid pressurized to atmospheric pressure or higher, for example, 5 MPa to atmospheric pressure. ing.

From the above examination results, when the second and subsequent wafers W are processed, the reason why more particles are attached than in the case of the first wafer is that supercritical CO ₂ remaining in the fluid supply line 351 causes the processing vessel 31 to remain. It is presumed that this is caused by the fact that the pressure is rapidly reduced in the processing container 31 and a large amount of mist (particles) is generated in the processing container 31 when being discharged to the outside.

In addition, even when CO ₂ having the same purity is used, the contents of these moisture and oil are different for each manufacturer and each cylinder, and it is difficult to eliminate the cause of the generation of particles at the raw material stage. Therefore, it is necessary to take measures against the generation of particles on the supercritical processing apparatus side where CO ₂ is used. In particular, the particles generated by such a process include particles having a minute size such as a particle size of about 40 nm. For example, a cleaning process of the wafer W on which a fine wiring pattern having a line width interval of 20 nm or less is formed. And it becomes a problem when performing subsequent drying.

From the above viewpoint, the supercritical processing apparatus 3 according to the present embodiment performs high-pressure fluid (supercritical CO ₂ , liquid CO ₂ , high-pressure gas) remaining in the fluid supply line 351 after processing the wafer W. When releasing the CO ₂ ) and releasing the atmosphere, a sudden pressure change is not generated in the processing container 31, so that contamination inside the processing container 31 and contamination of the wafer W due to mist water or oil are prevented. It is preventing. It has been experimentally confirmed in an example described later that this method can significantly reduce particles adhering to the wafer W during the second and subsequent processing.

Hereinafter, the structure of the supercritical processing apparatus 3 concerning this Embodiment and the washing | cleaning system 1 provided with this supercritical processing apparatus 3 is demonstrated.
First, as an example of a substrate processing system including the supercritical processing apparatus 3 of the present embodiment, a cleaning apparatus 2 that supplies a cleaning liquid to a wafer W that is a substrate to be processed and performs the cleaning process, and a wafer W that has been subjected to the cleaning process A cleaning processing system 1 including a supercritical processing apparatus 3 that removes a liquid for preventing drying (IPA) adhering to the surface by contacting with supercritical CO ₂ will be described.

  FIG. 1 is a cross-sectional plan view showing the overall configuration of the cleaning processing system 1, and FIG. 2 is an external perspective view thereof. In the cleaning system 1, the FOUP 100 is mounted on the mounting unit 11, and a plurality of wafers W having a diameter of, for example, 300 mm stored in the FOUP 100 are transferred to the subsequent cleaning processing unit via the loading / unloading unit 12 and the transfer unit 13. 14 is transferred to and from the supercritical processing unit 15 and is sequentially carried into the cleaning device 2 and the supercritical processing device 3 to perform a cleaning process and a process 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 denotes a wafer transferred between the loading / unloading unit 12, the cleaning processing unit 14, and the supercritical processing unit 15. W is a delivery shelf that serves as a buffer on which W is temporarily placed.

  The cleaning processing unit 14 and the supercritical processing unit 15 are provided in this order from the front along the wafer transfer path 162 extending in the front-rear direction from the opening between the transfer processing unit 13 and the transfer processing unit 13. In the cleaning processing unit 14, one cleaning device 2 is disposed across the wafer transfer path 162. On the other hand, in the supercritical processing section 15, six supercritical processing apparatuses 3, which are substrate processing apparatuses according to the present embodiment, are arranged in three units with the wafer transfer path 162 interposed therebetween.

  The wafer W is transferred between the cleaning device 2, the supercritical processing device 3, and the delivery unit 13 by the second transfer mechanism 161 arranged in the wafer transfer path 162. Here, the number of cleaning apparatuses 2 and supercritical processing apparatuses 3 arranged in the cleaning processing section 14 and the supercritical processing section 15 is the same as the number of wafers W processed per unit time, the cleaning apparatus 2 and the supercritical processing apparatus 3. The optimum layout is selected according to the number of the cleaning apparatuses 2 and supercritical processing apparatuses 3 arranged.

  The cleaning apparatus 2 is configured as a single wafer cleaning apparatus 2 that cleans wafers W one by one, for example, by spin cleaning, and is disposed in an outer chamber 21 that forms a processing space, as shown in a vertical side view of FIG. The wafer holding mechanism 23 holds the wafer W substantially horizontally, and the wafer W is rotated by rotating the wafer holding mechanism 23 around the vertical axis. Then, the nozzle arm 24 is advanced above the rotating wafer W, and the chemical liquid and the rinsing liquid are supplied in a predetermined order from the chemical liquid nozzle 241 provided at the tip of the wafer arm 24, whereby the wafer surface is cleaned. Further, a chemical solution supply path 231 is also formed inside the wafer holding mechanism 23, and the back surface of the wafer W is cleaned by the chemical solution and the rinsing solution supplied therefrom.

  The cleaning process is, for example, removal of particles and organic pollutants with an SC1 solution (a mixture of ammonia and hydrogen peroxide solution), which is an alkaline chemical solution, and a rinse with deionized water (DIW), which is a rinse solution. → Removal of natural oxide film by dilute hydrofluoric acid aqueous solution (hereinafter referred to as DHF (Diluted HydroFluoric acid)) which is an acidic chemical solution → Rinse cleaning by DIW is performed. These chemical solutions are received by the inner cup 22 or the outer chamber 21 disposed in the outer chamber 21 and discharged from the drain ports 221 and 211. The atmosphere in the outer chamber 21 is exhausted from the exhaust port 212.

  When the cleaning process using the chemical solution is completed, the rotation of the wafer holding mechanism 23 is stopped, and then IPA (IsoPropyl Alcohol) is supplied to the front and back surfaces of the wafer W to replace the DIW remaining on these surfaces. The wafer W that has been cleaned in this manner has a delivery mechanism (not shown) provided in the wafer holding mechanism 23 in a state in which IPA is accumulated on the surface (a state in which an IPA liquid film is formed on the surface of the wafer W). Is transferred to the second transport mechanism 161 and unloaded from the cleaning device 2.

  The IPA accumulated on the surface of the wafer W by the cleaning apparatus 2 evaporates during the transfer of the wafer W from the cleaning apparatus 2 to the supercritical processing apparatus 3 or during the loading operation to the supercritical processing apparatus 3 ( It plays a role as an anti-drying liquid that prevents pattern collapse from occurring due to vaporization.

After the cleaning process in the cleaning apparatus 2 is completed, the wafer W on which the IPA for preventing drying is deposited on the surface is transferred to the supercritical processing apparatus 3, and the supercritical CO is transferred to the IPA on the surface of the wafer W in the processing container 31. ₂ , the IPA is dissolved and removed in supercritical CO ₂ and the wafer W is dried. Hereinafter, the configuration of the supercritical processing apparatus 3 according to the present embodiment will be described with reference to FIGS. 4 and 5. Further, in the supercritical processing apparatus 3 shown in FIGS. 4 and 5, the same components as those of the conventional supercritical processing apparatus 3 described with reference to FIGS. 18 and 19 are used in these drawings. The same code | symbol is attached | subjected.

The supercritical processing apparatus 3 according to the present embodiment includes a processing container 31 that performs a process for removing IPA that is a liquid for preventing drying adhered to the surface of a wafer W, and a supercritical fluid that is a high-pressure fluid in the processing container 31. And a fluid supply source 37 for supplying CO ₂ .

  As shown in FIG. 5, the processing container 31 includes a housing-like container main body 311 in which an opening 312 for carrying in / out the wafer W is formed, a holding plate 331 for holding the wafer W to be processed horizontally, A lid member 332 that supports the holding plate 331 and seals the opening 312 when the wafer W is loaded into the container body 311 is provided.

The container main body 311 is a container in which a processing space of about 200 to 10000 cm ³ that can accommodate a wafer W having a diameter of 300 mm, for example, is formed, and a wall for supplying a high-pressure fluid into the processing container 31 A fluid supply line 351 (fluid supply path) and a discharge line 341 (discharge path) for discharging the fluid in the processing container 31 are connected. Further, the processing container 1 is pressed against the internal pressure received from the high-pressure fluid in a high-pressure state supplied into the processing space, and the lid member 332 is pressed toward the container main body 311 to seal the processing space (not shown). A mechanism is provided.

A fluid supply line 351 connected to the processing container 1 is connected to a fluid supply source 37 through an on-off valve 352, a filter 353, and a flow rate adjustment valve 354 that open and close in accordance with the supply and stop of high-pressure fluid to the processing container 1. ing. Fluid supply source 37, for example, a CO ₂ cylinder for storing the liquid CO _2, to a supercritical state by boosting the liquid CO ₂ which is supplied from the CO ₂ cylinder, the booster made of a syringe pump or a diaphragm pump With a pump. In FIG. 4 and the like, these CO ₂ cylinders and booster pumps are generally shown in the form of cylinders.

The flow rate of supercritical CO ₂ supplied from the fluid supply source 37 is adjusted by the flow rate adjustment valve 354 and supplied to the processing vessel 31. The flow rate adjustment valve 354 is constituted by, for example, a needle valve, and is also used as a shut-off unit that shuts off the supply of supercritical CO ₂ from the fluid supply source 37.

  In addition, the pressure reducing valve 342 of the discharge line 341 is connected to a pressure controller 343, and the pressure controller 343 includes a measurement result of the pressure in the processing container 31 obtained from the pressure gauge 321 provided in the processing container 31, in advance. A feedback control function is provided for adjusting the opening degree based on the comparison result with the set pressure.

  The cleaning processing system 1, the cleaning apparatus 2, and the supercritical processing apparatus 3 having the configuration described above are connected to the control unit 4 as shown in FIGS. 1 and 4. The control unit 4 includes a computer including a CPU and a storage unit (not shown). The storage unit is operated by the cleaning processing system 1, the cleaning apparatus 2, and the supercritical processing apparatus 3, that is, the wafer W is taken out from the FOUP 100 and cleaned. Steps (commands) for control related to operations from the cleaning process at 2 and the drying process of the wafer W by the supercritical processing apparatus 3 to the loading of the wafer W into the FOUP 100 are assembled. Recorded programs. This program is stored in a storage medium such as a hard disk, a compact disk, a magnetic optical disk, or a memory card, and installed in the computer therefrom.

  In particular, for the supercritical processing apparatus 3, the control unit 4 depressurizes the processing container 31 and the fluid supply line 351 together before taking out the processed wafer W, thereby moving the fluid supply line 351 toward the processing container 31. And a function of outputting a control signal so as to avoid a sudden pressure change in the pressure reducing direction. From such a viewpoint, as shown in FIG. 4, the control unit 4 includes a pressure controller 343 that adjusts the opening degree of the pressure reducing valve 342 provided in the discharge line 341, an on-off valve 352 on the fluid supply line 351 side, and a flow rate adjustment. The valve 354 is electrically connected.

  The operation of the supercritical processing apparatus 3 having the above-described configuration will be described with reference to the operation diagrams of FIGS. In each figure, the symbol “S” attached to the valves 354, 352, and 342 indicates that the open / close valve is closed, and the symbol “O” indicates that the valve is open. Yes.

  As described above, after the cleaning process in the cleaning apparatus 2 is completed and the wafer W on which the IPA for preventing drying is accumulated is transferred to the second transfer mechanism 161, the second transfer mechanism 161 receives the wafer W. A possible supercritical processing device 3 is entered into the housing.

At this time, the supercritical processing apparatus 3 before carrying in the wafer W waits in a state where the opening / closing valve 352 of the fluid supply line 351 and the pressure reducing valve 342 of the discharge line 341 are closed after the inside of the processing container 31 is opened to the atmosphere. doing. In addition, the fluid supply line 351 is previously opened to the atmosphere, and the on-off valve 352 and the flow rate adjustment valve 354 are closed in a state where high-pressure CO ₂ does not remain inside.

  When the wafer W filled with IPA is loaded into the processing container 31 waiting in the above state, the holding plate 331 is moved out of the container body 311 as shown in FIG. The wafer W is transferred from the transfer arm of the second transfer mechanism 161 to the holding plate 331 via the pins. Then, the holding plate 331 is moved to carry the wafer W into the container main body 311 through the opening 312, the opening 312 is closed by the lid member 332, and the inside of the processing container 31 is sealed (FIG. 6).

Next, the opening / closing valve 352 of the fluid supply line 351 is opened and the opening degree of the flow rate adjustment valve 354 is adjusted to introduce supercritical CO ₂ into the processing vessel 31 at a predetermined flow rate (FIG. 7). At this time, as described above, the moisture and oil contained in the raw material CO ₂ are also brought into the processing container 31, but by introducing supercritical CO ₂ , the processing container 31 is changed from atmospheric pressure to CO ₂ . Since the pressure is increased to a pressure equal to or higher than the critical pressure, these water and oil components are maintained in the supercritical CO ₂ state. Here, the thick arrows shown in FIG. 7 and the like indicate that the fluid flows in the piping such as the fluid supply line 351 and the discharge line 341.

In the pressure controller 343, a target pressure in the processing container 31 is set. When the pressure in the processing container 31 exceeds the target pressure, the pressure reducing valve 342 is opened and one of the supercritical CO ₂ in the processing container 31 is opened. The pressure in the processing container 31 is adjusted by extracting the part from the discharge line 341 (FIG. 8). In the surface of this time the wafer W, puddle been IPA on the wafer W is in contact with the supercritical CO _2, IPA from the surface of the wafer W is extracted into the supercritical CO ₂ is gradually removed.

Eventually, the supercritical CO ₂ enters the pattern formed on the surface of the wafer W, and extracts and removes the IPA in the pattern. As a result, the IPA filling the pattern is replaced with supercritical CO ₂ and removed from the surface of the wafer W.

At this time, as shown in FIG. 8, a part of the supercritical CO ₂ from which IPA is extracted in the processing vessel 31 is extracted from the discharge line 341, and the supply of new supercritical CO ₂ from the fluid supply line 351 is continued. Thereby, the process of removing IPA can be advanced without significantly reducing the extraction ability of IPA by supercritical CO ₂ in the processing container 31.

Thus, when sufficient time has passed to extract the IPA that has entered the pattern and replace it with supercritical CO ₂ , the pressure control by the pressure controller 343 is canceled and the pressure reducing valve 342 of the discharge line 341 is closed, The flow rate adjustment valve 354 is closed to shut off the supply of supercritical CO ₂ from the fluid supply source 37 (FIG. 9). At this time, the insides of the processing vessel 31 and the fluid supply line 351 are filled with supercritical CO ₂ .

When the supply of supercritical CO ₂ is stopped, the pressure reducing valve 342 is opened to discharge the supercritical CO ₂ inside the piping of the processing container 31 and the fluid supply line 351, thereby connecting the processing container 31 and the fluid supply line 351. Combine with reduced pressure. In this operation, the supercritical CO ₂ remaining in the processing vessel 31 and the fluid supply line 351 changes as “supercritical CO ₂ → high pressure CO ₂ gas → low pressure CO ₂ gas” as the pressure decreases, The oil retention capacity declines.

However, at this time, the inside of the processing container 31 and the inside of the pipe of the fluid supply line 351 are decompressed together, so that a large pressure difference is not formed between the fluid supply line 351 and the processing container 31, and the internal CO ₂ is reduced. Can be discharged. That is, in the supercritical processing apparatus 3 of the present example, when CO ₂ in the fluid supply line 351 flows into the processing container 31, a rapid pressure reduction is not generated as compared with the conventional supercritical processing apparatus described in FIG. .

As a result, it is possible to prevent the moisture and oil content held in the supercritical CO ₂ from being misted in the processing container 31, and to discharge CO ₂ to the outside while maintaining the moisture and oil content. The water and oil that has been held in the supercritical CO ₂ is to mist at a location downstream of the pressure reducing valve 342 of the discharge line 341, it is allowed to flow back CO ₂ discharged from the discharge line 341 to the processing chamber 31 For example, these mists do not become a contamination source that contaminates the inside of the processing container 31.

In this way, the water and oil retained in CO ₂ remain in the processing container 31 and adhere to the inner wall surface of the container main body 311 by reducing the pressure in the processing container 31 so that it is not easily misted. The amount of mist to be reduced can be reduced, and the adhesion of particles to the wafer W to be processed next can be reduced.
Then, the liquid IPA is removed from the pattern and the wafer W in a dry state can be obtained inside the processing container 31 whose pressure is reduced to atmospheric pressure. Here, the container body 311 is provided with a heating unit such as a tape heater, the temperature in the processing container 31 is maintained at a temperature higher than the dew point of IPA, and the IPA to the surface of the wafer W accompanying a temperature decrease due to adiabatic expansion of CO _2. Condensation may be prevented.

  After the inside of the processing container 31 is opened to the atmosphere and a dried wafer W is obtained, the holding plate 331 is moved to unload the wafer W from the processing container 31, and the wafer W is transferred to the transfer arm of the second transfer mechanism 161. Deliver. Thereafter, the wafer W is transferred to the first transfer mechanism 121 via the carry-out shelf 43 and stored in the FOUP 100 through a path opposite to that at the time of loading, and a series of operations on the wafer W is completed.

The supercritical processing apparatus 3 according to the present embodiment has the following effects. Contacting the supercritical CO ₂ in the liquid IPA attached to the wafer W with supercritical CO _2, after finishing the process of removing the liquid IPA, the processing vessel 31 of the processing is performed, and the processing chamber 31 Since the pressure of the fluid supply line 351 for supplying supercritical CO ₂ is reduced at the same time, the fluid is supplied via the processing container 31 without causing a sudden pressure difference between the fluid supply line 351 and the processing container 31. Supercritical CO ₂ inside the line 351 can be discharged to the outside. As a result, the pressure reduction width when the supercritical CO ₂ remaining in the fluid supply line 351 flows into the processing container 31 is reduced, and contamination inside the processing container 31 due to the density reduction of the supercritical CO ₂ is generated. Can be suppressed.

Thus, according to the idea of preventing contamination inside the processing container 31 by not performing a rapid depressurization operation of supercritical CO ₂ or high-pressure CO ₂ gas in the processing container 31, the super The discharge route of critical CO ₂ is not limited to the case of discharging from the discharge line 341 through the processing container 31.

For example, in the supercritical processing apparatus 3 shown in FIGS. 11 to 15, a dedicated branch line 361 (branch path) for extracting supercritical CO ₂ from the fluid supply line 351 is provided so as to branch from the fluid supply line 351. This is different from the supercritical processing apparatus 3 of the first embodiment shown in FIG. In the supercritical processing apparatus 3 shown in FIGS. 11 to 15, the same components as those in the supercritical processing apparatus 3 shown in FIG. 4 are denoted by the same reference numerals as those shown in FIG. Moreover, in FIGS. 11-15, description of the pressure gauge 321 and the pressure controller 343 is abbreviate | omitted.

The branch line 361 branches from a pipe of the fluid supply line 351 sandwiched between the on-off valve 352 and the flow rate adjustment valve 354 and is inserted into the pipe of the fluid supply line 351 separated from the processing container 31 and the fluid supply source 37. The remaining supercritical CO ₂ can be discharged. The branch line 361 is provided with a pressure reducing valve 362 (first on-off valve).

When the wafer W is carried in, the processing container 31, the fluid supply line 351, and the branch line 361 are opened to the atmosphere, and then waited with the valves 342, 352, 354, and 362 being closed (FIG. 11). When the wafer W filled with IPA is loaded into the processing container 31, the opening / closing valve 352 of the fluid supply line 351 is opened and the opening of the flow rate adjustment valve 354 is adjusted to a preset amount. Supercritical CO ₂ is supplied into the processing vessel 31 (FIG. 12).

When the pressure in the processing vessel 31 exceeds the target pressure, the liquid adhering to the surface of the wafer W is adjusted while the supercritical CO ₂ is extracted from the discharge line 341 by adjusting the opening of the pressure reducing valve 342 as shown in FIG. The point of replacing IPA with supercritical CO ₂ is the same as the operation of the supercritical processing apparatus 3 according to the first embodiment shown in FIGS.

When the liquid IPA on the surface of the wafer W is removed in this way, the on-off valve 352 of the fluid supply line 351, the flow rate adjustment valve 354, and the pressure reducing valve 342 (second pressure reducing valve) of the discharge line 341 are closed to supply and discharge supercritical CO _2. To stop. Thereafter, as shown in FIG. 14, the pressure reducing valve 342 of the discharge line 341 is opened to discharge the supercritical CO ₂ in the processing container 31, and the inside of the processing container 31 is opened to the atmosphere to prepare for taking out the wafer W. At this time, since the on-off valve 352 of the fluid supply line 351 and the pressure reducing valve 362 of the branch line 361 are “closed”, supercritical CO ₂ remains in the piping of the fluid supply line 351. Note that the processing vessel 31 may be opened to the atmosphere by closing only the on-off valve 352 and the flow rate adjustment valve 354 on the fluid supply line 351 side without temporarily closing the pressure reducing valve 342 of the discharge line 341.

After the processing vessel 31 is opened to the atmosphere or in parallel with this operation, the pressure reducing valve 362 of the branch line 361 is opened, and supercritical CO ₂ remaining in the pipe of the fluid supply line 351 is discharged to the outside. (FIG. 15). At this time, the supercritical CO ₂ and high-pressure CO ₂ gas flowing through the branch line 361 are suddenly depressurized when passing through the pressure reducing valve 362, and the water and oil contained in the raw material CO ₂ may be misted. The CO ₂ does not pass through the processing container 31. Therefore, mist generated when supercritical CO ₂ in the fluid supply line 351 is discharged does not remain inside the processing container 31 or adhere to the wall surface of the processing container 31, and the next processing time. This does not cause contamination of the wafer W.

The supercritical processing apparatus 3 according to the second embodiment has the following effects. Separately from the discharge line 341 that discharges the fluid from the processing container 31 that has been subjected to the process of removing the liquid IPA by bringing supercritical CO ₂ into contact with the liquid IPA that has adhered to the wafer W, the processing container 31. A branch line 361 branched from a fluid supply line 351 for supplying supercritical CO ₂ is provided. As a result, the supercritical CO ₂ remaining in the fluid supply line 351 can be discharged without going through the processing container 31, thereby suppressing the occurrence of contamination due to the density reduction when the supercritical CO ₂ flows into the processing container. it can.

Here, in the above-described embodiments, as shown in FIG. 8, FIG. 13, while continuously supplying supercritical CO ₂ from the fluid supply line 351, withdrawn supercritical CO ₂ in the processing chamber 31 from the discharge line 341 Although the case where the IPA on the surface of the wafer W is replaced has been described, the IPA replacement method is not limited to this method. For example, the valves 342 and 352 of the discharge line 341 and the fluid supply line 351 are closed to extract a liquid for preventing drying as a supercritical fluid in the processing container 31 in a batch state, and the liquid is replaced and removed. Also good.

In addition, the configuration of the supply blocking unit provided in the fluid supply source 37 is not limited to the case where the flow rate adjustment valve 354 shown in FIGS. 4 and 11 is used. For example, an on-off valve may be provided in place of the flow rate adjustment valve 354, or a booster pump for bringing the liquid CO ₂ supplied from the CO ₂ cylinder into a supercritical state may be used as the supply cutoff unit. In the latter case, supply and shutoff of high-pressure fluid are switched by operating and stopping a booster pump such as a syringe pump.

In each of the above-described embodiments, the case where supercritical CO ₂ is supplied as a high-pressure fluid and the liquid on the surface of the wafer W is removed has been described, but the state of the high-pressure fluid supplied from the fluid supply line 351 is the same. It is not limited. For example, CO ₂ in a subcritical state may be supplied to replace the liquid on the surface of the wafer W.

Alternatively, liquid CO ₂ or high-pressure CO ₂ gas may be supplied to the processing vessel 31 as a raw material fluid, and the CO ₂ may be heated in the processing vessel 31 to be replaced with a liquid in a supercritical state or a subcritical state. Good. If the fluid has the property that the retention of the causative substance of the particles contained in the raw material decreases due to the decrease in density as the atmosphere is released to the atmosphere, supercritical state, subcritical state, liquid, high-pressure gas The effect of the present invention can be obtained for the fluid supplied in any state.

The type of high-pressure fluid is not limited to CO ₂ , and wafers using various alcohols such as IPA, methanol and ethanol, various supercritical fluids such as HFE (Hydro Fluoro Ether) and acetone, subcritical fluids, and high-pressure gas are used. It may be replaced with the above anti-drying liquid. Also, the type of liquid for preventing drying is not limited to IPA, and various alcohols such as methanol and ethanol, various HFE (Hydro Fluoro Ether), acetone, pure water, and the like may be used.

  Further, in wafer processing to which the present invention can be applied, a high-pressure fluid is supplied from a fluid supply source 37 in a supercritical state or a subcritical state (collectively referred to as a high-pressure state), or a high-pressure fluid is high-pressure in a processing vessel 31. It is not limited to the process of extracting the liquid on the surface of the wafer W into a high-pressure fluid and removing the liquid by setting the state. For example, a wafer to be removed from the surface of the wafer W by providing a heating unit for heating the liquid for preventing drying of the surface of the wafer W in the processing container 31 and changing the liquid to a high pressure state (supercritical state or subcritical state). The present invention can also be applied to a processing apparatus.

  However, in this case, the pattern collapse occurs when the liquid on the surface of the wafer W changes to a high pressure state via a gas state. Therefore, a pressurizing high-pressure fluid for pressurizing the inside of the processing container 31 is supplied from the fluid supply source 37 so that the pressure in the processing container 31 becomes higher than the vapor pressure of the liquid on the surface of the wafer W before heating. The liquid may be removed from the wafer W by directly changing the liquid to a high pressure state. When the liquid on the surface of the wafer W is in a high pressure state, the dried wafer W can be obtained by opening the processing container 31 to the atmosphere while maintaining the temperature of the processing container 31 at or above the dew point of the liquid.

Specific examples of a method for directly changing the liquid for preventing drying on the surface of the wafer W to a high pressure state include IPA (critical temperature: 235 ° C., critical pressure: 4.8 MPa (absolute pressure)), Supercritical CO ₂ (critical temperature 31 ° C., critical pressure 7.4 MPa (absolute pressure)) may be used as the pressurized fluid (high pressure fluid). When the liquid IPA is heated in the processing vessel 31 supplied with supercritical CO ₂ , the liquid IPA is heated to an atmosphere higher than the critical pressure of the IPA, so that the liquid IPA is converted into the supercritical IPA without passing through the gas state. Can be changed directly. Further, from the viewpoint of preventing vaporization of IPA, the pressurized fluid does not need to be supercritical CO ₂ , and gas CO ₂ or subcritical CO ₂ having a pressure higher than the critical pressure of IPA may be supplied. Of course.

  When the liquid on the surface of the wafer W is removed by such a method, the liquid for preventing drying is supplied from the fluid supply source 37 as long as it is a substance that does not become a liquid under the temperature and pressure conditions at which the drying prevention liquid enters a high pressure state. The high-pressure fluid for pressurization may be supplied in a high-pressure state or may be supplied in a gas state having a pressure higher than atmospheric pressure. Even after the high-pressure fluid for pressurization is supplied from the fluid supply source 37, the processing vessel 31 and the fluid supply line 351 are decompressed together as shown in FIG. As shown in the drawing, by reducing the pressure of the processing container 31 and the fluid supply line 351 using separate lines 341 and 361, adhesion of particles to the wafer W in the processing container 31 can be prevented.

(Experiment 1)
In the supercritical processing apparatus 3 shown in FIG. 4, after processing for removing IPA on the surface of the wafer W using supercritical CO ₂ , the processing container 31 is released to the atmosphere, and the fluid is passed through the processing container 31. The state of adhesion of particles to the wafer W carried into the processing container 31 was compared between when the supply line 351 was opened to the atmosphere and when the supply line 351 was not opened to the atmosphere.

A. Experimental conditions
(Reference Example 1)
After the cleaning process, the wafer W filled with IPA was loaded into the cleaned processing container 31, and supercritical CO ₂ was supplied for 60 minutes to replace the IPA as shown in FIG. During this treatment, the temperature inside the treatment container 31 was 40 ° C., and the pressure was 10 MPa (absolute pressure). After the processing, the processing container 31 was opened to the atmosphere, and the wafer W was taken out. Next, as shown in FIG. 19, the supercritical CO ₂ remaining in the pipe of the fluid supply line 351 was discharged through the processing vessel 31 and released into the atmosphere. Thereafter, the second wafer W, to which no liquid is attached, is carried into the processing container 31 and left for 600 seconds. Then, the wafer W is taken out and has a diameter of 40 nm or more attached to the surface of the wafer W. I counted the number of particles. The particle count was performed by a particle inspection apparatus manufactured by KLA Tencor.
(Reference Example 2)
After the first wafer W is taken out, the second wafer W is loaded into the processing container 31 and taken out under the same conditions as in (Reference Example 1) except that the fluid supply line 351 is not opened to the atmosphere. The number of particles having a diameter of 40 nm or more adhering to the surface of the wafer W was counted.

B. Experimental Results In the experiment of (Reference Example 1), the number of particles adhering to the surface of the wafer W was 2712, and in the experiment of (Reference Example 2), 627. From the results of these experiments, the atmosphere of the processing container 31 and the fluid supply line 351 is separately released, and the supercritical CO ₂ remaining in the pipe of the fluid supply line 351 is released to the outside through the processing container 31. When discharged, it can be confirmed that the number of particles present in the processing container 31 increases and causes contamination of the wafers W carried in the second and subsequent wafers.

(Experiment 2)
Three wafers W were continuously processed by the method according to the present invention and the conventional method, and the number of particles adhering to the processed wafer W was compared.

A. Experimental conditions
Example 1
Processing that removes the IPA from the wafer W on which the liquid IPA is accumulated using the cleaned processing container 31, and then decompresses the processing container 31 and the fluid supply line 351 together to release the atmosphere. (FIGS. 6 to 10) were continuously performed on the three wafers W. The processing conditions of the wafer W such as the temperature and pressure in the processing container 31 are the same as in (Reference Example 1). The number of particles having a diameter of 40 nm or more adhering to the surface of each wafer W after processing was counted.
(Comparative Example 1)
After performing the process of removing the liquid IPA on the surface of the wafer W using supercritical CO ₂ (FIGS. 6 to 8), the processing container 31 and the fluid supply line 351 are opened to the atmosphere as shown in FIGS. The three wafers W were successively processed under the same conditions as in Example 1 except that the processes were performed separately. After the treatment, the number of particles having a diameter of 40 nm or more attached to each wafer W was counted.

B. Experimental result
The result of (Example 1) is shown in FIG. 16, and the result of (Comparative Example 1) is shown in FIG. According to the result of (Example 1) shown in FIG. 16, the number of particles having a diameter of 40 nm or more adhering to the wafer W is about 600 to 700, and the adhering of particles irrespective of the processing order of the wafer W. There were no major fluctuations in numbers.

  On the other hand, in the experimental result in which the processing container 31 and the fluid supply line 351 are separately opened to the atmosphere (Comparative Example 1), the first wafer W is the second wafer W in the processing order. More than four times as many particles are attached, and the particle contamination is greatly increased. As confirmed in (Reference Example 1), the processing container 31 and the fluid supply line 351 are separately opened to the atmosphere, and the atmosphere of the fluid supply line 351 is opened toward the processing container 31, thereby processing containers. It is considered that this is a result of the generation of particles in 31 and the contamination of the second and subsequent wafers W caused by the particles.

  When the experimental results of (Example 1) and (Comparative Example 1) are compared, the processing container 31 and the fluid supply line 351 are decompressed together and opened to the atmosphere as shown in FIG. It was confirmed that the generation of particles in the wafer can be suppressed and particle contamination of the wafer W in the subsequent processing can be suppressed.

  Further, as discussed above, when (Reference Example 1) and (Reference Example 2) are compared, the fluid supply line 351 is not opened to the atmosphere toward the processing container 31 (Reference Example 2). However, the number of particles adhering to the wafer W loaded next into the processing container 31 was small. From this fact, as shown in FIGS. 11 to 15, the wafer W is also applied to a method in which a branch line 361 is provided in the fluid supply line 351 and the fluid supply line 351 is decompressed and released to the atmosphere so as not to pass through the processing container 31. It can be seen that this is an effective technique for suppressing the adhesion of particles to the surface.

W Wafer 1 Cleaning system 2 Cleaning device 3 Supercritical processing device 31 Processing vessel 341 Discharge line 342 Pressure reducing valve 351 Fluid supply line 352 On-off valve 354 Flow rate adjusting valve 361 Branching line 362 Pressure reducing valve 37 Fluid supply source 4 Control unit

Claims (11)

A processing container in which a high-pressure fluid is brought into contact with the liquid for preventing drying on the surface of the substrate to remove the liquid for preventing drying;
A fluid supply source for supplying the high-pressure fluid or a raw material fluid of the high-pressure fluid at a pressure higher than atmospheric pressure;
A fluid supply path connecting the fluid supply source and the processing container;
A flow rate adjusting unit and an on-off valve provided in this order from the upstream side in the fluid supply path;
A shut-off unit provided on the upstream side of the flow rate adjustment unit in the fluid supply path, or also serving as a flow rate adjustment unit;
A pressure reducing valve for reducing the pressure in the processing container, and a discharge path for discharging the fluid in the processing container;
Open the shut-off unit and open the on-off valve with the flow rate adjusted by the flow rate adjustment unit to introduce a high-pressure fluid into the processing vessel, or introduce the raw material fluid to change into a high-pressure fluid, and dry from the surface of the substrate. Removing the liquid for prevention, and then reducing the pressure inside the fluid supply path and the processing container by bringing the shut-off portion into a shut-off state and opening the on-off valve and the pressure reducing valve. And a controller that outputs a control signal so as to execute the step of unloading the substrate from the processing container and then closing the on-off valve . A processing container in which a high-pressure fluid is brought into contact with the liquid for preventing drying on the surface of the substrate to remove the liquid for preventing drying;
A fluid supply source for supplying the high-pressure fluid or a raw material fluid of the high-pressure fluid at a pressure higher than atmospheric pressure;
A fluid supply path connecting the fluid supply source and the processing container;
A flow rate adjusting unit and an on-off valve provided in this order from the upstream side in the fluid supply path;
A shut-off unit provided on the upstream side of the flow adjustment unit in the fluid supply path, or also serving as a flow rate adjustment unit;
A branch path provided with a first pressure reducing valve for branching from the fluid supply path between the shut-off portion and the on-off valve and discharging and depressurizing the fluid in the fluid supply path;
A second pressure reducing valve for reducing the pressure in the processing container, and a discharge path for discharging the fluid in the processing container;
While closing the first pressure reducing valve, the shut-off unit is opened, the flow rate is adjusted by the flow rate adjusting unit, the open / close valve is opened to introduce a high-pressure fluid into the processing vessel, or the raw material fluid is introduced to increase the pressure A step of removing the liquid for preventing drying from the surface of the substrate by changing to a fluid; and then, the shut-off portion is shut off and the on-off valve is closed, while the second pressure reducing valve is opened. Reducing the pressure inside the processing container; and after the shut-off section is shut off and the on-off valve is closed, the first pressure reducing valve is opened to allow the fluid remaining in the fluid supply path to flow from the branch path. A substrate processing apparatus comprising: a control unit that outputs a control signal so as to execute the discharging step.   The high-pressure fluid is a fluid in a supercritical state or a subcritical state, and the processing vessel is supplied with a high-pressure fluid from the fluid supply source, or the raw material fluid is heated in the processing vessel to increase the pressure. 3. The substrate processing apparatus according to claim 1, wherein the liquid for preventing drying is extracted into the high-pressure fluid and removed from the surface of the substrate by becoming a fluid. The processing container includes a heating unit for heating the liquid for preventing drying of the surface of the substrate,
The high-pressure fluid is a fluid for pressurization for preventing vaporization of the liquid for preventing drying, which does not become liquid when the liquid for preventing drying is heated to a supercritical state or a subcritical state. ,
The drying-preventing liquid is heated by the heating unit in a pressurized atmosphere in contact with the high-pressure fluid, and is removed from the surface of the substrate by directly changing from the liquid to a supercritical state or a subcritical state. The substrate processing apparatus according to claim 1, wherein the apparatus is a substrate processing apparatus.   5. The substrate processing apparatus according to claim 1, wherein a process for removing a liquid for preventing drying is performed from a substrate on which a pattern having a line width of 20 nm or less is formed.   6. The pressure in the processing container at the time of performing the process of removing the drying preventing liquid from the substrate is 5 MPa or more, and the pressure in the processing container is reduced to atmospheric pressure. The substrate processing apparatus according to any one of the above. A processing vessel in which a high-pressure fluid is brought into contact with the drying-preventing liquid on the surface of the substrate to remove the drying-preventing liquid, and the high-pressure fluid or a raw material fluid of the high-pressure fluid A fluid supply source for supplying in a high pressure state, a fluid supply path connecting the fluid supply source and the processing container, a flow rate adjusting unit and an on-off valve provided in this order from the upstream side to the fluid supply path, Provided upstream of the flow rate adjusting unit in the fluid supply path, or a shut-off unit that also serves as the flow rate adjusting unit, and a pressure reducing valve for reducing the pressure in the processing vessel are provided, and the fluid in the processing vessel A substrate processing method using a discharge path for discharging
Open the shut-off unit and open the on-off valve with the flow rate adjusted by the flow rate adjustment unit to introduce a high-pressure fluid into the processing vessel, or introduce the raw material fluid to change into a high-pressure fluid, and dry from the surface of the substrate. Removing the prevention liquid;
Next, the process of depressurizing the inside of the fluid supply path and the processing container by setting the shut-off part in a shut-off state while opening the on-off valve and the pressure reducing valve,
And then unloading the substrate from the processing container and closing the on-off valve . A processing vessel in which a high-pressure fluid is brought into contact with the drying-preventing liquid on the surface of the substrate to remove the drying-preventing liquid, and the high-pressure fluid or a raw material fluid of the high-pressure fluid A fluid supply source for supplying in a high pressure state, a fluid supply path connecting the fluid supply source and the processing container, a flow rate adjusting unit and an on-off valve provided in this order from the upstream side to the fluid supply path, A fluid that is provided upstream of the flow rate adjusting unit in the fluid supply path, or is branched from a fluid supply path between the shut-off unit and the on-off valve, and a fluid in the fluid supply path. And a branch passage provided with a first pressure reducing valve for reducing pressure and a second pressure reducing valve for reducing the pressure in the processing container are provided to discharge the fluid in the processing container. And a substrate processing method using I,
While closing the first pressure reducing valve, the shut-off unit is opened, the flow rate is adjusted by the flow rate adjusting unit, the open / close valve is opened to introduce a high-pressure fluid into the processing vessel, or the raw material fluid is introduced to increase the pressure Changing to a fluid and removing the anti-drying liquid from the surface of the substrate;
Next, the process of depressurizing the inside of the processing vessel by setting the shut-off portion in a shut-off state and closing the on-off valve while opening the second pressure reducing valve,
And a step of opening the first pressure reducing valve and discharging the fluid remaining in the fluid supply passage from the branch passage after the shut-off portion is in a shut-off state and the on-off valve is closed. Processing method.   9. The substrate processing method according to claim 7, wherein a process for removing a liquid for preventing drying is performed from a substrate on which a pattern having a line width of 20 nm or less is formed.   10. The pressure in the processing container when performing the process of removing the liquid for preventing drying from the substrate is 5 MPa or more, and the pressure in the processing container is reduced to atmospheric pressure. The substrate processing method as described in any one of these. A storage medium storing a computer program used in a substrate processing apparatus for performing a process of removing a liquid for preventing drying by bringing a high-pressure fluid into contact with the liquid for preventing drying on the surface of the substrate,
A storage medium characterized in that the program includes steps for executing the substrate processing method according to any one of claims 7 to 10.

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