JP7109989B2 - SUBSTRATE PROCESSING METHOD, STORAGE MEDIUM AND SUBSTRATE PROCESSING SYSTEM - Google Patents

Description

The present invention relates to a substrate processing method, a storage medium, and a substrate processing system.

In the manufacturing process of semiconductor devices in which a layered structure of integrated circuits is formed on the surface of a substrate such as a semiconductor wafer (hereinafter referred to as "wafer"), cleaning liquids such as chemicals are used to remove fine dust and natural oxide films on the wafer surface. Processing steps have been performed that utilize liquids to treat wafer surfaces.

A method of using a supercritical processing fluid to remove the liquid remaining on the surface of the wafer in such a processing step is known. For example, Patent Document 1 discloses a substrate processing apparatus that dries a wafer by dissolving an organic solvent on the substrate using a supercritical fluid.

In the substrate processing apparatus disclosed in Patent Document 1, the surface of the wafer is cleaned with a cleaning liquid such as a chemical solution inside the processing apparatus. After cleaning, the surface of the wafer is covered with an organic solvent as a processing liquid. The wafer filled with the organic solvent is transported from the cleaning apparatus to the supercritical processing apparatus, and dried in the supercritical processing apparatus using the processing fluid in the supercritical state. By depositing the organic solvent on the surface of the wafer in this manner, the surface of the wafer after cleaning is prevented from drying before being dried in the supercritical processing apparatus, thereby preventing the generation of particles. there is

Japanese Unexamined Patent Application Publication No. 2013-12538

However, if the amount of the organic solvent deposited on the surface of the wafer after cleaning is too small, the organic solvent may evaporate before the drying process is performed in the supercritical processing apparatus. On the other hand, if the amount of liquid heaped up is too large, there is a risk that particles will be generated on the wafer after drying processing in the supercritical processing apparatus. For this reason, it is required that the organic solvent on the surface of the wafer after cleaning is deposited in a desired amount with high accuracy.

The present invention has been made in consideration of the above points, and provides a substrate processing method, a storage medium, and a substrate capable of improving the accuracy of the thickness of the liquid film of the processing liquid formed on the surface of the substrate. A processing system is provided.

One embodiment of the present invention is
a liquid film forming step of supplying a processing liquid to the surface of the substrate while rotating the substrate at a first rotation speed to form a liquid film of the processing liquid covering the surface of the substrate;
a supply stop step of stopping the supply of the treatment liquid to the substrate while reducing the number of revolutions of the substrate to the first number of revolutions or less after the liquid film forming process;
and a liquid amount adjusting step of reducing the liquid amount of the treatment liquid forming the liquid film by increasing the rotational speed of the substrate to be higher than the first rotational speed after the supply stop step. , substrate processing method,
I will provide a.

Also, another embodiment of the present invention is
A storage medium recording a program that, when executed by a computer for controlling the operation of a substrate processing system, causes the computer to control the substrate processing system to perform the substrate processing method described above;
I will provide a.

Also, another embodiment of the present invention is
a holding part that horizontally holds the substrate;
a rotation drive unit that rotates the holding unit;
a processing liquid supply unit that supplies processing liquid to the substrate held by the holding unit;
a control unit;
a liquid film forming step in which the control unit supplies the processing liquid to the surface of the substrate while rotating the substrate at a first rotation speed to form a liquid film of the processing liquid covering the surface of the substrate; After the liquid film forming step, a supply stop step of stopping the supply of the processing liquid to the substrate while reducing the rotation speed of the substrate to the first rotation speed or less, and after the supply stop step and a liquid amount adjusting step of reducing the liquid amount of the treatment liquid forming the liquid film by setting the number of revolutions of the substrate to a second number of revolutions larger than the first number of revolutions. a substrate processing system that controls a driving unit and the processing liquid supply unit;
I will provide a.

According to the present invention, it is possible to improve the accuracy of the thickness of the liquid film of the processing liquid formed on the surface of the substrate.

FIG. 1 is a cross-sectional plan view of the substrate processing system according to the first embodiment. FIG. 2 is a vertical cross-sectional view of a cleaning device provided in the substrate processing system shown in FIG. 3 is a diagram showing an IPA supply system in the cleaning apparatus of FIG. 1. FIG. FIG. 4 is an external perspective view of a processing container of the supercritical processing apparatus. 5 is a cross-sectional view showing an example of the processing container shown in FIG. 4. FIG. FIG. 6(a) is a cross-sectional view showing the periphery of the maintenance opening of the processing container shown in FIG. 5, and FIG. FIG. 4 is a diagram showing; FIG. 7 is a system diagram of the supercritical processing apparatus in the first embodiment. FIG. 8(a) is a diagram for explaining the second rinsing step in the substrate processing method according to the first embodiment, and FIG. 8(b) is a diagram for explaining the IPA liquid film forming step. 8(c) is a diagram for explaining the supply stop process, and FIG. 8(d) is a diagram for explaining the liquid volume adjustment process. FIG. 9 is a diagram showing changes in the rotation speed of the substrate in the substrate processing method of FIG. FIGS. 10(a) to 10(d) are diagrams for explaining the drying mechanism of IPA, and are enlarged cross-sectional views schematically showing patterns as recesses of the wafer. FIG. 11 is a cross-sectional view for explaining a maintenance method for a processing container of a supercritical processing apparatus. 12(a) is a modification of the cross-sectional view showing the periphery of the maintenance opening of the processing container shown in FIG. 5, and FIG. 12(b) is a cross-sectional view of the second lid member of FIG. 12(a). is. FIG. 13(a) is a diagram for explaining the IPA liquid filling step in the substrate processing method according to the second embodiment, and FIG. 13(b) is a diagram for explaining the second liquid amount adjusting step is a diagram. FIG. 14 is a diagram showing changes in the number of rotations of the substrate in the substrate processing method of FIG.

(First embodiment)
An embodiment of a substrate processing method, a storage medium, and a substrate processing system according to the present invention will be described below with reference to the drawings. It should be noted that the configurations shown in the drawings attached to this specification may include portions whose sizes, scales, etc. are changed from those of the actual ones for the sake of ease of illustration and understanding.

[Configuration of substrate processing system]
As shown in FIG. 1, a substrate processing system 1 includes a plurality of cleaning devices 2 (two cleaning devices 2 in the example shown in FIG. 1) that supply a cleaning liquid to a wafer W to perform cleaning processing, and a cleaning device after cleaning processing. A processing liquid for drying prevention remaining on the wafer W (IPA: isopropyl alcohol, which is an example of an organic solvent in this embodiment) is brought into contact with a processing fluid in a supercritical state (CO ₂ : carbon dioxide in this embodiment). and a plurality of supercritical processing apparatuses 3 (two supercritical processing apparatuses 3 in the example shown in FIG. 1) for removing the particles.

In this substrate processing system 1, a FOUP 100 is mounted on a mounting section 11, and a wafer W stored in this FOUP 100 is transferred to a cleaning processing section 14 and a supercritical processing section 15 via a loading/unloading section 12 and a transfer section 13. be handed over. In the cleaning processing section 14 and the supercritical processing section 15 , the wafer W is first carried into the cleaning device 2 provided in the cleaning processing section 14 and subjected to cleaning processing, and then transferred to the supercritical processing section 15 provided in the supercritical processing section 15 . The wafer W is carried into the processing apparatus 3 and subjected to a drying process for removing IPA from the wafer. In FIG. 1, reference numeral "121" indicates a first transfer mechanism for transferring wafers W between the FOUP 100 and the transfer section 13, and reference numeral "131" indicates the loading/unloading section 12, the cleaning processing section 14, and the supercritical processing section. 15, a transfer rack serving as a buffer on which wafers W transferred to and from 15 are temporarily placed.

A wafer transfer path 162 is connected to the opening of the transfer section 13 , and along the wafer transfer path 162 a cleaning processing section 14 and a supercritical processing section 15 are provided. In the cleaning processing section 14, one cleaning device 2 is arranged with the wafer transfer path 162 interposed therebetween, and two cleaning devices 2 are installed in total. On the other hand, in the supercritical processing section 15, the supercritical processing apparatuses 3 for performing a drying process for removing IPA from the wafer W are arranged one by one with the wafer transfer path 162 interposed therebetween. A device 3 is installed. A second transfer mechanism 161 is arranged in the wafer transfer path 162 , and the second transfer mechanism 161 is provided movably within the wafer transfer path 162 . The wafer W placed on the transfer shelf 131 is received by the second transfer mechanism 161 , and the second transfer mechanism 161 loads the wafer W into the cleaning apparatus 2 and the supercritical processing apparatus 3 . The number and arrangement of the cleaning apparatuses 2 and the supercritical processing apparatuses 3 are not particularly limited, and may depend on the number of wafers W processed per unit time, the processing time of each cleaning apparatus 2 and each supercritical processing apparatus 3, and the like. , a suitable number of cleaning units 2 and supercritical processing units 3 are arranged in a suitable manner.

As shown in FIG. 2, the cleaning apparatus 2 is configured as a single-wafer type apparatus that cleans wafers W one by one by spin cleaning, for example. That is, as shown in the vertical cross-sectional view of FIG. 2, the wafer W is held substantially horizontally by a wafer holding mechanism 23 (holding portion) arranged in an outer chamber 21 forming a processing space. The wafer W is rotated by rotating the wafer holding mechanism 23 around the vertical axis by means of the motor 20 (rotational drive unit). Then, the nozzle arm 24 is advanced above the rotating wafer W, and the chemical solution for cleaning, the rinse solution, and the IPA are applied appropriately to the processing surface of the wafer W from the respective nozzles 25 to 28 provided at the tip of the arm. The cleaning process of the wafer W is performed by supplying it at appropriate timing. 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 with the chemical solution and rinse solution supplied from the chemical solution supply path 231 .

A first chemical liquid nozzle 25 , a second chemical liquid nozzle 26 , a rinse liquid nozzle 27 and an IPA nozzle 28 are provided at the tip of the nozzle arm 24 .

The first chemical liquid nozzle 25 supplies the wafer W with SC1 liquid (that is, a mixed liquid of ammonia and hydrogen peroxide), which is an alkaline chemical liquid. This SC1 liquid is a chemical liquid for removing particles and organic contaminants from the wafer W. FIG. Although not shown, the first chemical solution nozzle 25 is connected to a first chemical solution supply source via a first chemical solution supply line, and the first chemical solution supply line is provided with a first chemical solution on-off valve. SC1 is supplied from the first chemical liquid supply source to the first chemical liquid nozzle 25 by opening the first chemical liquid on-off valve.

The second chemical liquid nozzle 26 supplies the wafer W with a dilute hydrofluoric acid solution (DHF), which is an acidic chemical liquid. This DHF is a chemical solution for removing a natural oxide film formed on the surface of the wafer W. As shown in FIG. Although not shown, the second chemical solution nozzle 26 is connected to a second chemical solution supply source via a second chemical solution supply line, and the second chemical solution supply line is provided with a second chemical solution on-off valve. DHF is supplied from the second chemical liquid supply source to the second chemical liquid nozzle 26 by opening the second chemical liquid on-off valve.

The rinse liquid nozzle 27 supplies the wafer W with deionized water (DIW), which is a rinse liquid. This DIW is a liquid for washing away the SC1 liquid or DHF from the wafer W. FIG. A rinse liquid supply source (not shown) is connected to the rinse liquid nozzle 27 via a rinse liquid supply line, and the rinse liquid supply line is provided with a rinse liquid on-off valve. By opening the rinse liquid on-off valve, DIW is supplied from the rinse liquid supply source to the rinse liquid nozzle 27 .

The IPA nozzle 28 supplies the wafer W with IPA, which is a processing liquid for drying prevention. This IPA is a processing liquid for preventing the wafer W from drying. In particular, the supply of IPA to the wafers W aims to prevent the wafers W from drying during transfer from the cleaning apparatus 2 to the supercritical processing apparatus 3 . In order to prevent so-called pattern collapse on the wafer W due to vaporization of IPA during transfer, IPA is applied to the wafer W so that a liquid film of IPA having a relatively large thickness is formed on the surface of the wafer W. W is deposited on the surface. As shown in FIG. 3 , the IPA nozzle 28 is connected to an IPA supply source 30 via an IPA supply line 29 , and the IPA supply line 29 is provided with an IPA on-off valve 31 . By opening the IPA on-off valve 31 , IPA is supplied from the IPA supply source 30 to the IPA nozzle 28 . The IPA nozzle 28 , the IPA supply line 29 , the IPA supply source 30 and the IPA on-off valve 31 constitute an IPA supply section 32 (processing liquid supply section).

The chemicals used for cleaning the wafer W are not limited to the SC1 liquid and DHF, and are optional. Further, instead of providing the rinse liquid nozzle 27 on the nozzle arm 24, the DIW may be selectively discharged from the first chemical liquid nozzle 25 and the second chemical liquid nozzle 26. FIG.

Such chemicals, DIW and IPA are received by the inner cup 22 and the outer chamber 21 arranged in the outer chamber 21 and discharged from the drain ports 221 and 211, as shown in FIG. Also, the atmosphere in the outer chamber 21 is exhausted from the exhaust port 212 .

The wafer W unloaded from the cleaning apparatus 2 is carried into the processing container 301 of the supercritical processing apparatus 3 in a state of being filled with IPA by the second transfer mechanism 161 shown in FIG. A drying process of IPA is performed in .

[Supercritical processing equipment]
Next, the details of the drying process using the supercritical fluid performed in the supercritical processing apparatus 3 will be described. First, a configuration example of a processing container into which wafers W are loaded in the supercritical processing apparatus 3 will be described.

4 is an external perspective view showing an example of the processing container 301 of the supercritical processing apparatus 3, and FIG. 5 is a cross-sectional view showing an example of the processing container 301. As shown in FIG.

The processing container 301 accommodates the wafers W and processes the wafers W using a high-pressure processing fluid such as a supercritical fluid. As shown in FIGS. 4 and 5, the processing container 301 includes a housing-shaped container body 311 for accommodating the wafer W, a transfer port 312 for loading and unloading the wafer W into and out of the container body 311, and a processing chamber. It has a holding plate 316 that holds the target wafer W sideways, and a first lid member 315 that supports the holding plate 316 and seals the transfer opening 312 when the wafer W is carried into the container body 311 . . A maintenance opening 321 is provided in the container body 311 at a position different from the transfer port 312 . The maintenance opening 321 is closed by the second lid member 322 except during maintenance.

The container main body 311 accommodates the wafers W and processes the wafers W using a processing fluid. The container main body 311 is a container in which a processing space 319 capable of accommodating a wafer W having a diameter of 300 mm, for example, is formed. The above-described transfer port 312 and maintenance opening 321 (for example, openings of the same size and shape as the transfer port 312 ) are formed at both ends of the processing space 319 and communicate with the processing space 319 .

A discharge port 314 is provided on the wall portion of the container body 311 on the side of the transfer port 312 . The discharge port 314 is connected to a discharge-side supply line 65 (see FIG. 7) provided on the downstream side of the processing container 301 for circulating the processing fluid. Although two discharge ports 314 are illustrated in FIG. 4, the number of discharge ports 314 is not particularly limited.

A first upper block 312a and a first lower block 312b located above and below the transfer port 312 are formed with fitting holes 325 and 323 for fitting a first lock plate 327, which will be described later. . The fitting holes 325 and 323 penetrate the first upper block 312a and the first lower block 312b in the vertical direction (the direction perpendicular to the surface of the wafer W).

The holding plate 316 is a thin plate-like member that can be arranged horizontally in the processing space 319 of the container body 311 while holding the wafer W, and is connected to the first lid member 315 . A discharge port 316a is provided on the holding plate 316 on the first lid member 315 side.

A first lid member accommodation space 324 is formed in a region of the container body 311 on the front side (Y-direction negative side). The first lid member 315 is housed in the first lid member housing space 324 when the holding plate 316 is carried into the processing container 301 and the wafer W is subjected to supercritical processing. In this case, the first lid member 315 closes the transfer port 312 to seal the processing space 319 .

The first lock plate 327 is provided on the front side of the processing container 301 . The first lock plate 327 functions as a restricting member that restricts the movement of the first lid member 315 due to the pressure inside the container body 311 when the holding plate 316 is moved to the processing position. The first lock plate 327 is fitted into the fitting hole 323 of the first lower block 312b and the fitting hole 325 of the first upper block 312a. At this time, since the first lock plate 327 functions as a bar, the first lid member 315 and the holding plate 316 are restricted from moving in the front-rear direction (the Y direction in FIGS. 4 and 5). . The first lock plate 327 has a lock position where it is fitted into the fitting holes 323 and 325 to hold down the first lid member 315 and an open position where it retreats downward from this lock position and opens the first lid member 315 . , it is moved vertically by the lifting mechanism 326 . In this example, the first lock plate 327 , the fitting holes 323 and 325 , and the lifting mechanism 326 constitute a regulation mechanism that regulates the movement of the first lid member 315 due to the pressure inside the container body 311 . Note that the fitting holes 323 and 325 are provided with margins necessary for inserting and removing the first lock plate 327, respectively, so there is no gap between the fitting holes 323 and 325 and the first lock plate 327 at the locked position. is formed with a slight gap C1 (FIG. 5). For convenience of illustration, the gap C1 is exaggerated in FIG.

The maintenance opening 321 is provided on the wall surface of the container body 311 at a position facing the transfer port 312 . Since the maintenance opening 321 and the transfer port 312 face each other in this manner, when the container body 311 is sealed by the first lid member 315 and the second lid member 322, the pressure in the processing space 319 is applied to the inner surface of the container body 311. join approximately evenly. Therefore, concentration of stress on a specific portion of the container body 311 is prevented. However, the maintenance opening 321 may be provided at a location other than the position facing the transfer port 312, for example, on a wall surface on the side of the traveling direction of the wafer W (Y direction).

The second upper block 321a and the second lower block 321b are positioned above and below the maintenance opening 321, respectively. The second upper block 321a and the second lower block 321b are formed with fitting holes 335 and 333 for fitting the second lock plate 337, respectively. The fitting holes 335 and 333 pass through the second upper block 321a and the second lower block 321b in the vertical direction (direction perpendicular to the surface of the wafer W, Z direction).

A second lid member accommodating space 334 is formed in the region of the container body 311 on the back side (the positive side in the Y direction). The second lid member 322 is housed in the second lid member housing space 334 and closes the maintenance opening 321 except during maintenance or the like. A supply port 313 is provided in the second lid member 322 . The supply port 313 is provided upstream of the processing vessel 301 and connected to the first supply line 63 (see FIG. 7) for circulating the processing fluid. Although two supply ports 313 are illustrated in FIG. 4, the number of supply ports 313 is not particularly limited.

The second lock plate 337 functions as a restricting member that restricts movement of the second lid member 322 due to the pressure inside the container body 311 . This second lock plate 337 is fitted into the fitting holes 333 and 335 around the maintenance opening 321 . At this time, since the second lock plate 337 functions as a bolt, the movement of the second cover member 322 in the front-rear direction (Y direction) is restricted. The second lock plate 337 has a lock position where it is fitted into the fitting holes 333 and 335 to hold down the second cover member 322 and an open position where it retreats downward from this lock position and opens the second cover member 322 . It is configured to move vertically between. In this embodiment, the second lock plate 337 is manually moved, but a lifting mechanism substantially similar to the lifting mechanism 326 may be provided to automatically move the second lock plate 337 . Since the fitting holes 333 and 335 are provided with a margin necessary for inserting and removing the second lock plate 337, there is a gap between the fitting holes 333 and 335 and the second lock plate 337 at the locked position. A slight gap C2 (FIG. 5) is formed. For convenience of illustration, the gap C2 is exaggerated in FIG.

In this embodiment, the second lid member 322 is connected to the first supply line 63 and has a large number of openings 332 . The second lid member 322 serves as a fluid supply header that supplies the processing fluid supplied from the first supply line 63 through the supply port 313 to the interior of the container body 311 . Accordingly, when the second lid member 322 is removed during maintenance, maintenance work such as cleaning the opening 332 can be easily performed. A fluid discharge header 318 that communicates with the discharge port 314 is provided on the wall portion of the container main body 311 on the transfer port 312 side. This fluid discharge header 318 is also provided with a number of apertures.

The second lid member 322 and the fluid discharge header 318 are installed to face each other. The second lid member 322 functioning as a fluid supply unit supplies the processing fluid into the container body 311 in a substantially horizontal direction. The horizontal direction here is a direction perpendicular to the vertical direction in which gravity acts, and is generally parallel to the direction in which the flat surface of the wafer W held by the holding plate 316 extends. The fluid discharge header 318, which functions as a fluid discharge part for discharging the fluid in the container body 311, guides the fluid in the container body 311 to the outside of the container body 311 through a discharge port 316a provided in the holding plate 316 and discharges it. do. The fluid discharged to the outside of the container body 311 through the fluid discharge header 318 includes the processing fluid supplied into the container body 311 through the second lid member 322 and the processing fluid dissolved in the processing fluid from the surface of the wafer W. It contains an IPA. By supplying the processing fluid into the container body 311 through the openings 332 of the second lid member 322 and by discharging the fluid from the container body 311 through the openings of the fluid discharge header 318 in this way, the container A laminar flow of the processing fluid flowing substantially parallel to the surface of the wafer W is formed in the main body 311 .

Vacuum suction tubes 348 and 349 are connected to the side surface of the container body 311 on the side of the transport port 312 and the side surface on the side of the opening 321 for maintenance, respectively. The vacuum suction tubes 348 and 349 respectively communicate with the surface of the container body 311 on the side of the first lid member accommodation space 324 and the surface of the container body 311 on the side of the second lid member accommodation space 334 . The vacuum suction tubes 348 and 349 play a role of drawing the first lid member 315 and the second lid member 322 toward the container body 311 by vacuum suction force.

A bottom-side fluid supply section 341 for supplying the processing fluid to the inside of the container body 311 is formed on the bottom surface of the container body 311 . The bottom-side fluid supply section 341 is connected to a second supply line 64 (see FIG. 7) that supplies the processing fluid into the container body 311 . The bottom-side fluid supply unit 341 supplies the processing fluid into the container body 311 substantially upward. The processing fluid supplied from the bottom-side fluid supply unit 341 flows from the back surface of the wafer W through the discharge port 316a provided in the holding plate 316 to the front surface of the wafer W, and flows together with the processing fluid from the second lid member 322. The fluid is discharged from the fluid discharge header 318 through the discharge port 316 a provided in the retaining plate 316 . The position of the bottom-side fluid supply unit 341 is preferably below the wafer W introduced into the container main body 311, and more preferably below the central portion of the wafer W, for example. As a result, the processing fluid from the bottom-side fluid supply section 341 can be made to flow uniformly over the surface of the wafer W. FIG.

As shown in FIG. 5, heaters 345 made of resistance heating elements such as tape heaters are provided on both upper and lower surfaces of the container body 311 . The heater 345 is connected to a power supply unit 346, and can maintain the temperature of the container body 311 and the processing space 319 within a range of 100° C. to 300° C., for example, by increasing or decreasing the output of the power supply unit 346.

Next, the configuration around the maintenance opening 321 will be further described with reference to FIGS. 6(a) and 6(b).

As shown in FIG. 6A, a recess 328 is formed in the side wall of the second lid member 322 on the side of the processing space 319 so as to surround a position corresponding to the periphery of the maintenance opening 321 . By fitting the seal member 329 into the recess 328 , the seal member 329 is arranged on the side wall surface of the second lid member 322 that contacts the side wall surface around the maintenance opening 321 .

The seal member 329 is formed in an annular shape so as to surround the maintenance opening 321 . Moreover, the cross-sectional shape of the seal member 329 is U-shaped. In the seal member 329 shown in FIG. 6A, a U-shaped opening 329a is formed along the inner peripheral surface of the annular seal member 329. As shown in FIG. In other words, the sealing member 329 is formed with an internal space surrounded by a U-shape.

By closing the periphery of the maintenance opening 321 using the second lid member 322 provided with the seal member 329, the seal member 329 closes the gap between the second lid member 322 and the container body 311. , is arranged between the second lid member 322 and the container body 311 . Since this gap is formed around the maintenance opening 321 in the container body 311 , the opening 329 a formed along the inner peripheral surface of the sealing member 329 communicates with the processing space 319 . It's becoming

The seal member 329 whose opening 329a communicates with the processing space 319 is exposed to the atmosphere of the processing fluid, and the processing fluid may elute components such as resins and rubbers and impurities contained therein. be. Therefore, in the sealing member 329, at least the inner side of the opening 329a toward the processing space 319 is made of resin having corrosion resistance against the liquid IPA and the processing fluid. Examples of such resins include polyimide, polyethylene, polypropylene, paraxylene, and polyetheretherketone (PEEK), and even if a small amount of component is eluted into the processing fluid, the semiconductor device is less affected. , it is preferable to use a fluorine-free resin. A metal spring (not shown) is preferably provided on the inner surface of the U-shaped sealing member 329 (the surface facing the opening 329a). The spring is configured to apply a spring force in a direction to push the sealing member 329 outward (a direction to widen the opening 329a).

When the processing fluid enters the opening 329a, the seal member 329 is pushed out from the opening 329a, and the outer peripheral surface of the seal member 329 (the surface opposite to the opening 329a) and the recess 328 side surface of the second lid member 322 and A pressing force acts toward the side wall surface of the container body 311 . As a result, the outer peripheral surface of the seal member 329 is brought into close contact with the second lid member 322 and the container body 311 to airtightly block the gap between the second lid member 322 and the container body 311 . The sealing member 329 of this type has elasticity that allows it to be deformed by the force received from the processing fluid, and also seals the gap airtightly against the pressure difference (for example, about 16 to 20 MPa) between the processing space 319 and the outside. can be maintained. Further, as described above, when a metal spring is provided on the inner surface of the sealing member 329, the force of the spring causes the outer peripheral surface of the sealing member 329 (the surface opposite to the opening 329a) to move to the second position. The pressing force against the surface of the lid member 322 on the side of the recess 328 and the side wall surface of the container body 311 is increased, and the airtightness can be improved.

As shown in FIGS. 6A and 6B, the second lid member 322 is provided with a plurality of additional holes 330. As shown in FIGS. The additional opening 330 supplies the processing fluid supplied from the first supply line 63 through the supply port 313 to the opening 329 a of the sealing member 329 . Each additional opening 330 is provided for each opening 332 provided in the second lid member 322 , and a portion of the processing fluid flowing toward the opening 332 is extracted to provide an additional opening corresponding to the opening 332 . It is supplied from the opening 330 to the opening 329 a of the sealing member 329 . In addition, as shown in FIG. 6B, it is preferable that the additional opening 330 is also provided on the side portion of the second lid member 322. The processing fluid is also supplied to the side portion of the opening 321 .

Note that, in the present embodiment, the transfer port 312 of the container body 311 is also sealed by the first lid member 315 in the same manner as the transfer port 312 .

That is, as shown in FIG. 5, a recess 338 is formed in the side wall of the first lid member 315 on the processing space 319 side so as to surround a position corresponding to the peripheral edge of the transfer port 312 . By fitting the seal member 339 into the concave portion 338 , the seal member 339 is arranged on the side wall surface of the first lid member 315 that contacts the side wall surface around the transfer port 312 .

The sealing member 339 is formed in an annular shape so as to surround the transfer port 312 . Moreover, the cross-sectional shape of the seal member 339 is U-shaped. In this way, by closing the transfer port 312 using the first cover member 315 provided with the seal member 339 , the seal member 339 closes the gap between the first cover member 315 and the transfer port 312 . , is arranged between the first lid member 315 and the container body 311 . In addition, the configuration for closing the transfer port 312 using the first lid member 315 and the sealing member 339 is substantially the same as the configuration for closing the maintenance opening 321 described above.

[Overall System Configuration of Supercritical Processing Equipment]
FIG. 7 is a diagram showing a configuration example of the entire system of the supercritical processing apparatus 3. As shown in FIG.

As shown in FIGS. 4, 5, and 7, the second lid member 322 is connected to a first supply line 63 for supplying the processing fluid into the processing container 301. As shown in FIGS. A second supply line 64 for supplying the processing fluid into the processing container 301 is connected to the wall of the container body 311 . The second supply line 64 branches off from the first supply line 63 downstream of the on-off valve 67 . A discharge-side supply line 65 for discharging the fluid in the processing container 301 is connected to the bottom of the container body 311 .

A first supply line 63 connected to the processing container 301 is connected to the fluid supply tank 51 via an on-off valve 67, a filter 68, and a flow control valve 69, which are opened and closed according to the supply and stop of the high-pressure fluid to the processing container 301. It is The fluid supply tank 51 includes, for example, a CO2 cylinder for storing liquid CO2, and a booster pump such as a syringe pump or a diaphragm pump for increasing the pressure of the liquid CO2 supplied from the CO2 cylinder to a supercritical state. ing. In FIG. 7, these CO2 cylinders and booster pumps are generally shown in the shape of cylinders.

The supercritical CO 2 supplied from the fluid supply tank 51 is supplied to the processing container 301 after having its flow rate adjusted by the flow control valve 69 . The flow control valve 69 is composed of, for example, a needle valve, and is also used as a shutoff section for shutting off the supply of supercritical CO 2 from the fluid supply tank 51 .

Also, the pressure reducing valve 70 of the discharge side supply line 65 is connected to a pressure controller 71 , and the pressure controller 71 obtains the measurement result of the pressure inside the processing container 301 from a pressure gauge 66 provided in the processing container 301 . , and has a feedback control function that adjusts the opening based on the result of comparison with a preset set pressure.

The substrate processing system 1, the cleaning apparatus 2, and the supercritical processing apparatus 3 having the configurations described above are connected to the control unit 4 as shown in FIGS. The control unit 4 is, for example, a computer, and includes a calculation unit 18 and a storage unit 19 (not shown). The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1 . The calculation unit 18 controls the operation of the substrate processing system 1 by reading out and executing programs stored in the storage unit 19 . The program may be recorded in a computer-readable storage medium and installed in the storage unit 19 of the control unit 4 from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnet optical disks (MO), and memory cards.

In particular, in the supercritical processing apparatus 3, the control unit 4 decompresses both the processing container 301 and the first supply line 63 before taking out the processed wafer W so that the pressure from the first supply line 63 to the processing container 301 is reduced. It has a function of outputting a control signal to avoid sudden pressure changes in the decompression direction. From this point of view, as shown in FIG. 7, the control unit 4 includes a pressure controller 71 that adjusts the opening degree of a pressure reducing valve 70 provided in the discharge side supply line 65, and an on-off valve 67 on the first supply line 63 side. , is electrically connected to the flow control valve 69 .

Next, the operation of the present embodiment configured as described above, that is, the processing method (substrate processing method) of the wafer W in the substrate processing system 1 according to the present embodiment will be described.

[Washing process]
Here, first, a method for cleaning the wafer W in the cleaning apparatus 2 will be described.

<First chemical cleaning step>
First, the wafer W is held substantially horizontally by the wafer holding mechanism 23 of the cleaning apparatus 2 . Subsequently, the wafer holding mechanism 23 is rotated about the vertical axis to rotate the wafer W within the horizontal plane. Next, the nozzle arm 24 enters above the rotating wafer W, and the SC1 liquid is supplied as a cleaning chemical to the central portion of the surface of the wafer W from the first chemical nozzle 25 provided at the tip thereof. The SC1 liquid is spread by centrifugal force, and the entire surface of the wafer W is covered with the liquid film of the SC1 liquid, whereby the surface of the wafer W is cleaned with the SC1 liquid. In this case, particles and organic contaminants can be removed from the wafer W. FIG. The SC1 liquid on the surface of the wafer W scatters outward from the outer peripheral edge We of the wafer W in the radial direction. The scattered SC1 liquid is discharged from the drain ports 221 and 211 .

<First rinse step>
After the first chemical cleaning step, the wafer W is rinsed while being rotated. In this case, DIW (rinse liquid) is supplied to the central portion of the surface of the rotating wafer W from the rinse liquid nozzle 27 provided at the tip of the nozzle arm 24 . As a result, the DIW spreads due to the centrifugal force and can be washed away from the wafer W so as to expel the SC1 liquid. The DIW and SC1 liquid on the surface of the wafer W scatter radially outward from the outer peripheral edge We of the wafer W and are discharged from the liquid discharge ports 221 and 211 .

<Second chemical cleaning step>
After the first rinsing process, the wafer W is chemically cleaned with a DHF liquid. In this case, DHF as a cleaning chemical is supplied to the central portion of the surface of the rotating wafer W from the second chemical nozzle 26 provided at the tip of the nozzle arm 24 . The DHF is spread by centrifugal force, and the entire surface of the wafer W is covered with the DHF liquid film, thereby cleaning the surface of the wafer W with the DHF. In this case, the natural oxide film formed on the wafer W can be removed. The DHF liquid on the surface of the wafer W scatters radially outward from the outer peripheral edge We of the wafer W and is discharged from the liquid discharge ports 221 and 211 .

<Second rinse step>
After the second chemical cleaning process, the wafer W is rinsed as shown in FIGS. In this case, DIW is supplied to the central portion of the surface of the rotating wafer W from the rinsing liquid nozzle 27 provided at the tip of the nozzle arm 24 in the same manner as in the first rinsing step. As a result, the DIW spreads due to centrifugal force and can be washed away from the wafer W so as to expel the DHF. DIW and DHF on the surface of the wafer W scatter radially outward from the outer peripheral edge We of the wafer W and are discharged from the drain ports 221 and 211 .

In the second rinse step, for example, the DIW discharge rate is set to 300 mL/min, and the rotation speed of the wafer W is set to 1000 rpm. Then, a DIW liquid film is formed on the surface of the wafer W, as shown in FIG. 8A.

<IPA liquid film forming step>
After the second rinsing process, as shown in FIGS. 8B and 9, IPA is supplied to the wafer W as a drying prevention liquid while rotating the wafer W at the first rotation speed. In this case, first, the rotation speed of the wafer W is reduced to a first rotation speed lower than the rotation speed during the second rinsing process. Subsequently, the IPA on-off valve 31 is opened, and IPA is supplied from the IPA supply source 30 through the IPA supply line 29 to the IPA nozzle 28 provided at the tip of the nozzle arm 24 . The IPA supplied to the IPA nozzle 28 is supplied from the IPA nozzle 28 to the central portion of the surface of the rotating wafer W. As shown in FIG. The IPA spreads due to centrifugal force, and the DIW liquid film formed on the processing surface of the wafer W is replaced with IPA. As shown in FIG. A liquid film (a puddle of IPA filled with liquid) is formed. The IPA on the surface of the wafer W scatters radially outward from the outer peripheral edge We of the wafer W and is discharged from the drain ports 221 and 211 .

In the IPA liquid film forming process, for example, the discharge amount of IPA is set to 300 mL/min, the rotation speed of the wafer W is set to 30 rpm, and the discharge of IPA is continued for 15 seconds. As shown in FIG. 9, the number of rotations of the wafer W in the IPA liquid film formation process is smaller than the number of rotations of the wafer W in the liquid volume adjustment process, which will be described later. Therefore, the IPA is suppressed from scattering from the outer peripheral edge We of the wafer W, and the thickness of the IPA liquid film after the IPA liquid film forming process (t1 shown in FIG. 8B) is is thicker than the thickness of the IPA liquid film (t3 shown in FIG. 8D). That is, the heaping amount of IPA after the IPA liquid film forming process is made larger than the heaping amount of IPA after the liquid amount adjusting process.

<Supply stop process>
After the IPA liquid film forming step, as shown in FIGS. , the supply of IPA to wafer W is stopped. In this case, first, the rotation of the wafer W is stopped. At this time, it is preferable to stop the rotation of the wafer W gently. As a result, the IPA remaining on the surface of the wafer W can be prevented from being discharged from the surface of the wafer W. FIG. After that, the IPA on-off valve 31 is closed to stop the supply of IPA. Even after this supply stopping step, the IPA liquid film having a thickness of t2 remains on the surface of the wafer W, and the thickness t2 of this liquid film is equal to that of the IPA liquid film forming step described above. Although it is equal to or slightly thinner than the thickness t1 of the IPA liquid film afterward, it is thicker than the thickness t3 of the IPA liquid film after the liquid volume adjustment process described later.

<Liquid volume adjustment process>
After the supply stop step, as shown in FIGS. 8D and 9, the rotation speed of the wafer W is set to a second rotation speed larger than the first rotation speed to form a liquid film on the surface of the wafer W. Reduce the volume of IPA. In this case, the wafer holding mechanism 23 is rotated about the vertical axis to rotate the stopped wafer W again in the horizontal plane. Due to the centrifugal force generated by the rotation of the wafer W, part of the IPA forming the liquid film on the surface of the wafer W scatters radially outward from the outer peripheral edge We of the wafer W, and drain ports 221 and 211 discharged from On the other hand, during this time, the IPA on-off valve 31 is kept closed, and IPA is not supplied to the surface of the wafer W. FIG. In this way, the amount of IPA forming the liquid film is reduced, and the thickness t3 of the IPA liquid film is equal to the thickness t1 of the liquid film after the IPA liquid film forming step and the IPA liquid amount after the supply stopping step. It becomes thinner than the film thickness t2. This results in the desired thickness of the IPA liquid film.

In the liquid volume adjustment step, it is preferable to gently stop the rotation of the wafer W after a predetermined time (for example, 1 second) has elapsed since the rotation of the wafer W that had been stopped was restarted (increased). is. As a result, the IPA forming the liquid film is prevented from being excessively discharged from the surface of the wafer W, and the thickness t3 of the IPA liquid film can be adjusted to a desired thickness.

In the liquid volume adjustment step, the thickness of the IPA liquid film can be arbitrarily adjusted by adjusting the number of rotations of the wafer W and the time from when the rotation of the wafer W is restarted to when it is stopped. Further, in order to shorten the processing time of the wafer W, the time from restarting the rotation of the wafer W to stopping it is set short, and the thickness of the IPA liquid film is reduced to the desired thickness within this time. The rotation speed of the wafer W may be set so that it can be adjusted.

Thus, the cleaning process of the wafer W is completed. At this time, an IPA liquid film having a desired thickness is formed on the surface of the wafer W to prevent the wafer W from drying.

[Drying process]
Next, a method for drying the wafer W in the supercritical processing apparatus 3 will be described. Here, first, the drying mechanism of IPA will be described with reference to FIG.

<Drying mechanism>
In the supercritical processing apparatus 3, when the processing fluid R in the supercritical state is introduced into the container body 311 of the processing container 301, only IPA is filled between the patterns P as shown in FIG. 10(a). there is

The IPA between the patterns P gradually dissolves in the processing fluid R by coming into contact with the processing fluid R in the supercritical state, and gradually replaces the processing fluid R as shown in FIG. 10(b). At this time, between the patterns P, in addition to the IPA and the processing fluid R, a mixed fluid M in which the IPA and the processing fluid R are mixed exists.

As the replacement of IPA with the processing fluid R progresses between the patterns P, the IPA is removed from between the patterns P, and finally, as shown in FIG. Only the space between the patterns P is filled.

After the IPA is removed from between the patterns P, the pressure in the container body 311 is lowered to atmospheric pressure, so that the processing fluid R changes from a supercritical state to a gaseous state as shown in FIG. The P interval is occupied only by gas. Thus, the IPA between the patterns P is removed, and the drying process of the wafer W is completed.

With the mechanism shown in FIGS. 10(a) to 10(d) as a background, the supercritical processing apparatus 3 of the present embodiment performs drying processing of IPA as follows.

<Importing process>
After the liquid volume adjustment process, the wafer W is carried into the processing vessel 301 of the supercritical processing apparatus 3 in a state where the IPA liquid film having a desired thickness is formed.

In this case, first, the wafer W is unloaded from the cleaning apparatus 2 by the second transport mechanism 161 and loaded into the processing container 301 of the supercritical processing apparatus 3 . At the time of loading, the second transfer mechanism 161 transfers the wafer W to the holding plate 316 waiting at the transfer position, and then withdraws from the position above the holding plate 316 .

Next, the holding plate 316 is slid horizontally to move the holding plate 316 to the processing position inside the container body 311 . At this time, the first lid member 315 is housed in the first lid member housing space 324 and covers the transfer port 312 . Subsequently, the first lid member 315 is attracted to the container body 311 by the suction force from the vacuum suction tube 348 (FIGS. 4 and 5), and the transfer port 312 is closed by the first lid member 315 . Next, the lift mechanism 326 lifts the first lock plate 327 to the lock position, bringing the first lock plate 327 and the front surface of the first lid member 315 into contact with each other, thereby restricting the movement of the first lid member 315 .

<Drying process>
After the carrying-in process, the wafer W is dried. In the drying process, a pressurized processing fluid is supplied to the processing container 301 to maintain the pressure in the processing container 301 at a pressure at which the processing fluid maintains a critical state, and the processing fluid pressurized to the processing container 301 is supplied. is supplied and the processing fluid is discharged from the processing container 301 . As a result, the IPA on the wafer W is replaced with the processing fluid, and then the wafer W is dried by reducing the pressure in the processing container 301 .

More specifically, the on-off valve 67 and the flow control valve 69 are opened to allow the IPA liquid heaped up on the surface of the wafer W to be processed through the first supply line 63 and the second supply line 64 before it dries. A high pressure processing fluid is supplied to space 319 . As a result, the pressure in the processing space 319 is raised to, for example, approximately 14 to 16 MPa. As the processing space 319 is pressurized, the sealing member 339 having a U-shaped cross section provided in the concave portion 338 of the first lid member 315 is pushed out, and the gap between the first lid member 315 and the container body 311 is airtight. close to

On the other hand, in the processing space 319, when the processing fluid supplied into the processing space 319 comes into contact with the IPA that is heaped up on the wafer W, the heaped IPA is gradually dissolved in the processing fluid, and gradually replace with As the IPA is replaced with the processing fluid between the patterns of the wafer W, the IPA is removed from between the patterns, and finally, the space between the patterns P is filled only with the supercritical processing fluid. As a result, the liquid IPA is replaced with the processing fluid on the surface of the wafer W. However, since no interface is formed between the liquid IPA and the processing fluid in the equilibrium state, the pattern collapse does not occur on the wafer. The IPA on the W surface can be replaced by the treatment fluid.

After that, when the processing fluid is supplied to the processing space 319 and the processing fluid is supplied to the processing space 319 and the surface of the wafer W has been replaced with the processing fluid, the pressure reducing valve 70 is opened. Atmosphere is discharged from the fluid discharge header 318 toward the outside of the container body 311 . As a result, the pressure in the container body 311 gradually decreases, and the processing fluid in the processing space 319 changes from a supercritical state to a gaseous state. At this time, since no interface is formed between the supercritical state and the gas, the wafer W can be dried without exerting surface tension on the pattern formed on the surface of the wafer W.

After the supercritical processing of the wafer W is completed by the above process, in order to discharge the gaseous processing fluid remaining in the processing space 319, N ₂ gas is supplied from a purge gas supply line (not shown) to the fluid discharge header. Purge to 318 . Then, when the _N2 gas is supplied for a predetermined period of time, the purge is completed, and the inside of the container body 311 returns to atmospheric pressure, the first lock plate 327 is lowered to the open position. Then, the holding plate 316 is horizontally moved to the delivery position, and the wafer W that has undergone the supercritical processing is unloaded using the second transport mechanism 161 .

By the way, the second lock plate 337 is always raised to the lock position while the above-described supercritical processing is being performed. As a result, the second lock plate 337 and the rear surface of the second lid member 322 come into contact with each other, and the movement of the second lid member 322 is restricted. When the high-pressure processing fluid is not supplied to the processing space 319 and the pressure inside the container body 311 is not increased, the side wall surfaces of the second lid member 322 and the container body 311 are directly opposed to each other and the sealing member 329 is closed. is crushed to airtightly block the periphery of the maintenance opening 321 .

On the other hand, when a high-pressure processing fluid is supplied to the processing space 319, the second lid member 322 closes the processing space by a gap C2 between the insertion holes 335 and 333 around the maintenance opening 321 and the second lock plate 337. It moves away from 319 (Y-direction plus side). The movement of the second lid member 322 widens the gap between the second lid member 322 and the container body 311 . In this case, since the opening 329a widens due to the restoring force of the elastic sealing member 329, the outer peripheral surface of the sealing member 329 is brought into close contact with the second lid member 322 and the container body 311, and the second lid member 322 and the container body 311 are brought into close contact with each other. The gap between the is closed airtight. In this manner, the second lid member 322 keeps the maintenance opening 321 closed while the above-described supercritical processing is being performed.

Further, while the high-pressure processing fluid is being supplied from the first supply line 63 to the processing space 319, the processing fluid is supplied to the opening 329a of the sealing member 329 from the additional opening 330 provided in the second lid member 322. be. As a result, the processing fluid can be sprayed to the inside of the sealing member 329 to blow off foreign matter such as dust adhering to the inner surface of the sealing member 329 . Therefore, the inner surface of the seal member 329 can be cleaned while performing the supercritical treatment. The processing fluid supplied to the openings 329 a is supplied to the processing space 319 .

[Maintenance method]
Next, the action when maintenance of the processing container 301 is performed after the supercritical processing described above is completed will be described.

First, the inside of the processing space 319 is opened to atmospheric pressure. Next, the lift mechanism 326 moves the first lock plate 327 downward from the insertion holes 323 and 325 to the open position where the first cover member 315 is opened. Next, the first lid member 315 and the holding plate 316 are moved forward (minus side in the Y direction). As a result, the holding plate 316 is removed from the processing space 319, and the first lid member 315 is separated from the transfer port 312 (FIG. 11(a)).

Next, the second lock plate 337 is moved downward from the insertion holes 333 and 335 to an open position where the second cover member 322 is opened. Next, the second lid member 322 is moved to the back side (Y direction plus side) to separate the second lid member 322 from the maintenance opening 321 (FIG. 11B).

Subsequently, a cleaning jig, a tool, or the like is inserted from the maintenance opening 321 to perform maintenance work (cleaning, adjustment, etc.) inside the processing space 319 . In this embodiment, it is possible to access the inside of the processing space 319 simply by moving the second lock plate 337 downward and removing the second cover member 322, thereby facilitating such maintenance work. It can be carried out. Further, since the supply port 313 is connected to the second lid member 322, maintenance work (cleaning, adjustment, etc.) of the supply port 313 and the opening 332 can be easily performed in addition to the maintenance work in the processing space 319. be able to.

After the maintenance work is completed in this manner, the second lid member 322 and the first lid member 315 are respectively assembled to the container body 311 in the reverse steps described above. That is, first, the second lid member 322 is moved forward (minus side in the Y direction) to cover the maintenance opening 321 with the second lid member 322 . Next, the second lid member 322 is sucked toward the container body 311 by the suction force from the vacuum suction tube 349 . Next, the second lock plate 337 is lifted and fitted into the fitting holes 333 and 335 to reach the lock position where the second lid member 322 is pressed. As a result, the periphery of the maintenance opening 321 is airtightly closed.

Next, by moving the first lid member 315 and the holding plate 316 to the back side (the positive side in the Y direction), the holding plate 316 is caused to enter the processing space 319, and the transfer port 312 is closed by the first lid member 315. cover. Next, the first lid member 315 is sucked toward the container body 311 by the suction force from the vacuum suction tube 348 . Subsequently, the first lock plate 327 is lifted by the elevating mechanism 326, and the first lock plate 327 is fitted into the fitting holes 323 and 325 to be in the locked position. In this manner, the periphery of the transfer port 312 is airtightly closed, and the processing space 319 is sealed again. After that, the supercritical treatment described above is performed as necessary.

As described above, according to the present embodiment, the IPA liquid film is formed on the surface of the wafer W while rotating the wafer W at the first rotation speed, and then the rotation of the wafer W is stopped and the supply of IPA is stopped. After stopping, the wafer W is rotated at a second rotation speed that is higher than the first rotation speed. Accordingly, the thickness of the IPA liquid film can be adjusted by adjusting the rotational speed of the wafer W regardless of the timing of stopping the supply of IPA.

Here, a method of adjusting the thickness of the IPA liquid film by rotating the wafer W at a desired number of rotations and discharging a desired IPA discharge amount (supply amount) onto the wafer W for a predetermined period of time is also considered. be done. In this case, the rotation of the wafer W is stopped and the supply of IPA is stopped after a predetermined time has elapsed. The rotation of the wafer W is stopped by the controller 4 sending a stop command to the motor 20 that drives the wafer holding mechanism 23 to rotate. As a result, the time from when the control unit 4 issues a stop command to when the wafer W stops rotating is less likely to fluctuate. On the other hand, the supply of IPA is stopped by the controller 4 sending a closing command to the IPA on-off valve 31 . More specifically, the valve body drive section (not shown) of the IPA on-off valve 31 that receives the closing command from the control section 4 moves the valve body to close the internal flow path of the IPA on-off valve 31. . For this reason, it is considered that the time from when the control unit 4 issues a closing command to when the IPA on-off valve 31 closes tends to fluctuate and it becomes difficult to keep it constant. For this reason, the thickness of the IPA liquid film on the surface of the wafer W may fluctuate, making it difficult to maintain the desired thickness.

On the other hand, according to the present embodiment, as described above, after the rotation of the wafer W is stopped and the supply of IPA is stopped, the wafer W is transferred to the wafer W while the IPA is being supplied to the wafer W. is rotated at a second rotation speed that is greater than the rotation speed of (first rotation speed). Therefore, the thickness of the IPA liquid film can be adjusted by adjusting the rotational speed of the wafer W regardless of the stoppage of the supply of IPA. Therefore, it is possible to prevent the thickness of the IPA liquid film from fluctuating and to improve the accuracy of the thickness. In this case, it is possible to prevent the IPA from evaporating before the wafer W after the cleaning process is dried in the supercritical processing apparatus 3, and the particles on the wafer W after the drying process in the supercritical processing apparatus 3. can be prevented from occurring.

Further, according to the present embodiment, the rotation of the wafer W is stopped in the supply stop step of stopping the supply of IPA to the surface of the wafer W. FIG. As a result, the IPA remaining on the surface of the wafer W can be prevented from being discharged from the surface of the wafer W due to centrifugal force in the supply stop step, and the IPA liquid film on the wafer W can be maintained by surface tension. can be done. Therefore, the thickness of the liquid film at the start of the liquid volume adjustment process can be secured, and the IPA liquid film after the liquid volume adjustment process can be adjusted to a desired thickness.

Further, according to the present embodiment, in the supply stop step for stopping the supply of IPA to the surface of the wafer W, the supply of IPA is stopped after the rotation of the wafer W is stopped. That is, even if the control unit 4 simultaneously issues a stop command to the motor 20 and a close command to the IPA on-off valve 31, the IPA on-off valve 31 may close later than the wafer W stops rotating. . Also in this case, the IPA supplied after the wafer W stops rotating spills from the edge of the wafer W. FIG. As a result, the thickness of the IPA liquid film at the start of the liquid volume adjustment process can be suppressed from increasing, and the IPA liquid film after the liquid volume adjustment process can be adjusted to a desired thickness.

Further, according to the present embodiment, in the liquid amount adjustment process for reducing the liquid amount of IPA that forms the liquid film, the rotation of the wafer W is stopped after a predetermined time has passed since the number of rotations of the wafer W is increased. As a result, excessive discharge of the IPA forming the liquid film from the surface of the wafer W can be prevented. Therefore, the thickness of the IPA liquid film can be prevented from becoming thinner than the desired thickness, and the accuracy of the thickness of the IPA liquid film can be improved.

Further, according to the present embodiment, after the liquid amount adjustment step, the wafer W is loaded into the processing container 301 maintained at a pressure that maintains the critical state of the processing fluid, and the processing fluid at the pressure is applied to the wafer W. The processing fluid is discharged from the processing container 301 while being supplied. As a result, the wafer W can be dried by replacing the IPA forming the liquid film on the wafer W with the processing fluid and then reducing the pressure in the processing vessel 301 . Therefore, it is possible to prevent particles from being generated on the wafer W. FIG.

In the present embodiment described above, an example in which the rotation of wafer W is stopped in the supply stop step has been described. However, the present invention is not limited to this, and the wafer W may be rotated at the first rotation speed or at a rotation speed lower than the first rotation speed. In this case, the time required for the wafer W to reach the second rotational speed can be shortened in the liquid volume adjustment step.

Further, in the present embodiment described above, an example in which the plurality of openings 332 and the plurality of additional openings 330 are provided in the second lid member 322 has been described. However, it is not limited to this. For example, configurations as shown in FIGS. 12A and 12B may be used. In the modification shown in FIGS. 12A and 12B, a tubular fluid supply header 350 is provided on the surface of the second lid member 322 on the container body 311 side. The fluid supply header 350 extends in the direction perpendicular to the paper surface (the X direction shown in FIG. 4) on the surface of the second lid member 322 on the container body 311 side. Fluid supply header 350 is connected to first supply line 63 via supply port 313 . The fluid supply header 350 is also provided with a plurality of apertures 332 and a plurality of additional apertures 330 . As a result, the processing fluid supplied from the first supply line 63 can be supplied to the processing space 319 through the opening 332 and to the inner surface of the sealing member 329 through the additional opening 330. be able to.

(Second embodiment)
Next, a substrate processing method, a storage medium, and a substrate processing system according to the second embodiment of the present invention will be described with reference to FIGS. 13 and 14. FIG.

In the second embodiment shown in FIGS. 13 and 14, a peripheral supply step of supplying the processing liquid to the peripheral edge of the substrate while rotating the substrate and reducing the amount of the processing liquid forming the liquid film are performed. The main difference is that a second liquid volume adjustment step is further provided, and other configurations are substantially the same as those of the first embodiment shown in FIGS. 13 and 14, the same parts as in the first embodiment shown in FIGS. 1 to 12 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, after the liquid amount adjustment process shown in FIG. 8D, the edge supply process and the second liquid amount adjustment process are performed. In the following, the peripheral supply step and the second liquid volume adjustment step of the liquid processing method according to the present embodiment will be described in more detail.

<Periphery supply process>
After the liquid amount adjustment step, IPA is supplied to the peripheral edge Wa of the wafer W while rotating the wafer W at the third rotation speed, as shown in FIGS. 13A and 14 . In this case, first, the number of rotations of the wafer W is reduced to a third number of rotations lower than the number of rotations (second number of rotations) during the liquid volume adjustment process. Subsequently, the IPA nozzle 28 is positioned above the peripheral edge Wa of the wafer W. As shown in FIG. Next, the IPA on-off valve 31 is opened, and IPA is supplied from the IPA supply source 30 to the IPA nozzle 28 . The IPA supplied to the IPA nozzle 28 is supplied to the peripheral portion Wa of the surface of the rotating wafer W. As shown in FIG.

In the peripheral supply step, the wafer W is rotating at the third rotation speed at which the liquid pool can be formed. As a result, as shown in FIG. 13A, the IPA liquid film covering the surface of the wafer W is formed to swell at the peripheral edge Wa. A portion of the IPA supplied to the peripheral edge Wa scatters radially outward from the outer peripheral edge We of the wafer W and is discharged from the drainage ports 221 and 211 . Here, the peripheral edge Wa means a region extending from the outer peripheral edge We of the wafer W to a predetermined width. For example, the supply point of IPA to the wafer W (the position of the IPA nozzle 28) in the peripheral supply step may be located 20 mm inside the outer peripheral edge We of the wafer W. FIG. The IPA nozzle 28 can be positioned at the desired feed point by adjusting the entry position of the nozzle arm 24 shown in FIG.

The discharge amount (supply amount) of IPA to the peripheral portion Wa of the wafer W in the peripheral supply step may be equal to the discharge amount of IPA to the wafer W in the IPA liquid film forming step shown in FIG. 8B. In the peripheral supply step, for example, the IPA discharge amount is set to 300 mL/min, the rotation speed of the wafer W is set to 30 rpm, and the IPA discharge is continued for 4 seconds. As shown in FIG. 14, the number of rotations of the wafer W in the peripheral supply step (that is, the third number of rotations) is equal to the number of rotations of the wafer W in the IPA liquid film formation process (that is, the first number of rotations). good. In this case, the IPA is suppressed from scattering from the outer peripheral edge We of the wafer W, and the thickness t4 of the IPA liquid film on the peripheral edge Wa of the wafer W increases the IPA on the inner portion Wb located inside the peripheral edge Wa. is thicker than the liquid film thickness t3. That is, the IPA liquid film on the inner portion Wb is maintained at the liquid film thickness t3 after the liquid volume adjustment process. In addition, the thickness t4 of the IPA liquid film in the peripheral portion Wa after the peripheral portion supply step is greater than the thickness t5 of the IPA liquid film in the peripheral portion Wa after the second liquid volume adjustment step. That is, the heaping amount of IPA in the peripheral edge Wa after the peripheral edge supply step is made larger than the heaping amount of IPA in the peripheral edge Wa after the second liquid amount adjusting step.

<Second Liquid Volume Adjustment Step>
After the edge supply step, as shown in FIGS. 13B and 14, the supply of IPA to the wafer W is stopped and the wafer W is rotated while IPA is supplied to form a liquid film on the surface of the wafer W. Reduce liquid volume. In this case, first, the IPA on-off valve 31 is closed, and the supply of IPA to the wafer W is stopped. Subsequently, the rotation speed of wafer W is set to a fourth rotation speed that is higher than the third rotation speed and equal to or lower than the second rotation speed. As a result, the centrifugal force generated along with the rotation of the wafer W increases, and part of the IPA liquid heaped up on the peripheral edge Wa of the wafer W scatters radially outward from the peripheral edge We of the wafer W and is discharged. It is discharged from liquid ports 221 and 211 . Further, by setting the fourth rotation speed to be equal to or lower than the second rotation speed, movement of IPA from the inner portion Wb of the wafer W to the outer peripheral side is suppressed. On the other hand, during this time, the IPA on-off valve 31 is kept closed, and IPA is not supplied to the surface of the wafer W. FIG. In this manner, the thickness t3 of the IPA liquid film on the inner portion Wb of the wafer W is maintained at the thickness t3 after the liquid amount adjustment step shown in FIG. Reduce quantity. As a result, the thickness t5 of the IPA liquid film on the peripheral edge portion Wa becomes thinner than the thickness t4 of the IPA liquid film on the peripheral edge portion Wa after the peripheral edge supply step. Therefore, the thickness of the IPA liquid film on the peripheral portion Wa becomes a desired thickness, and the total amount of the IPA liquid deposited on the surface of the wafer W is adjusted to a desired amount.

Even during the second liquid volume adjustment step, the IPA liquid film is maintained in such a shape that it swells at the peripheral edge Wa of the wafer W due to the centrifugal force due to the rotation of the wafer W and the viscosity of the IPA. be. Further, the total heaping amount of IPA after the second liquid amount adjustment process of the present embodiment is the total heaping amount of IPA after the liquid amount adjustment process shown in FIG. 8D of the first embodiment. is equal to , the number of revolutions of the wafer W is increased in the liquid amount adjustment process before the peripheral edge supply process of the present embodiment, so that the amount of IPA heaped up after the liquid amount adjustment process is reduced. You should leave it.

In the second liquid volume adjustment step, the thickness of the IPA liquid film at the peripheral edge Wa is adjusted by adjusting the fourth rotation speed and the time from when the rotation starts at the fourth rotation speed to when it stops. It can be adjusted arbitrarily. In order to shorten the processing time of the wafer W, the time from restarting the rotation of the wafer W to stopping it is set short (for example, 1 second). The rotation speed of the wafer W may be set such that the thickness of the liquid film can be adjusted to a desired thickness.

Thus, the cleaning process of the wafer W is completed. At this time, an IPA liquid film having a desired thickness (or liquid heaping amount) is formed on the surface of the wafer W to prevent the wafer W from drying. This liquid film is formed so as to swell at the peripheral edge Wa of the wafer W, and is maintained in such a shape that the thickness at the peripheral edge Wa is greater than the thickness at the inner portion Wb.

After the cleaning process of the wafer W is completed, the drying process of the wafer W is performed in the same manner as in the first embodiment.

As described above, according to the present embodiment, IPA is supplied to the peripheral portion Wa of the wafer W while the wafer W is being rotated. As a result, the IPA liquid film can be formed so as to swell at the peripheral portion Wa of the wafer W. As shown in FIG.

Here, before the wafer W after the cleaning process is dried in the supercritical processing apparatus 3, the IPA in the peripheral edge Wa of the surface of the wafer W is the inner part Wb located inside the peripheral edge Wa. It is easier to vaporize than IPA in. As a result, the peripheral portion Wa of the wafer W may be dried first, and IPA may remain in the inner portion Wb. If the peripheral edge Wa of the wafer W dries first, so-called pattern collapse may occur at the peripheral edge Wa. In order to prevent the peripheral portion Wa of the wafer W from drying, a method of increasing the thickness of the entire IPA liquid film on the surface of the wafer W may be considered. However, in this method, since the amount of IPA liquid heaped up on the surface of the wafer W increases, particles tend to be generated on the surface of the wafer W after the drying process in the supercritical processing apparatus 3 .

On the other hand, according to the present embodiment, as described above, the IPA liquid film is formed so as to swell at the peripheral edge Wa of the wafer W. As shown in FIG. Therefore, the IPA can remain for a long time on the peripheral edge Wa of the wafer W, and it is possible to prevent the wafer W from drying first from the peripheral edge Wa. Therefore, it is possible to prevent the IPA from evaporating over the entire surface of the wafer W after the cleaning process until the drying process in the supercritical processing apparatus 3 is performed. On the other hand, in the inner portion Wb of the wafer W, it is possible to suppress an increase in the thickness of the IPA liquid film. As a result, an excessive increase in the amount of IPA liquid on the surface of the wafer W can be suppressed, and the generation of particles on the wafer W after the drying process in the supercritical processing apparatus 3 can be prevented.

Further, according to the present embodiment, the edge supply step of supplying IPA to the edge portion Wa of the wafer W is performed after the liquid amount adjustment step of reducing the amount of IPA that forms the liquid film. As a result, the IPA liquid film on the surface of the wafer W can be maintained for a long time in a shape that rises at the peripheral portion Wa. Therefore, it is possible to further prevent IPA from vaporizing over the entire surface of the wafer W before the drying process in the supercritical processing apparatus 3 is performed.

Further, according to the present embodiment, after the peripheral edge supplying step of supplying IPA to the peripheral edge portion Wa of the wafer W, the second liquid amount for reducing the liquid amount of the IPA forming the liquid film on the surface of the wafer W is set. An adjustment process is performed. As a result, the thickness of the IPA liquid film on the peripheral edge Wa of the wafer W can be adjusted, and the precision can be improved. Therefore, it is possible to further prevent particles from being generated on the wafer W after the drying process in the supercritical processing apparatus 3 .

Further, according to the present embodiment, in the second liquid volume adjustment step, the wafer W is rotated at a fourth rotation speed equal to or lower than the rotation speed (second rotation speed) of the wafer W in the liquid volume adjustment step prior to the peripheral edge supply step. Rotate by number. As a result, it is possible to suppress the movement of IPA from the inner portion Wb of the wafer W located inside the peripheral edge portion Wa to the outer peripheral side. Therefore, the thickness of the IPA liquid film in the inner portion Wb can be maintained at the thickness after the liquid volume adjustment process, and the accuracy of the liquid film thickness can be improved.

In the present embodiment described above, an example has been described in which the third rotation speed of wafer W in the peripheral supply process is equal to the first rotation speed of wafer W in the IPA liquid film forming process. However, the third rotation speed is not limited to this, and the third rotation speed may be larger or smaller than the first rotation speed as long as the IPA liquid film can be formed so as to rise at the peripheral edge Wa.

Further, in the present embodiment described above, an example in which the second liquid volume adjustment process is performed after the peripheral supply process has been described. However, it is not limited to this. For example, after the second rinsing step shown in FIG. 8A and before the IPA liquid film forming step shown in FIG. 8B, the peripheral supply step may be performed. Even in this case, the IPA liquid film can be formed so as to swell at the peripheral edge Wa of the wafer W. It can be maintained even after the liquid volume adjustment process.

In addition, the thickness of the IPA liquid film on the peripheral edge Wa of the wafer W can be adjusted by appropriately adjusting the ejection amount and ejection time of the IPA supplied to the peripheral edge Wa of the wafer W in the peripheral edge supply step, and the rotation speed of the wafer W. If the thickness can be adjusted with high accuracy, the second liquid volume adjustment step may be omitted. In this case, the amount of IPA discharged to the peripheral portion Wa of the wafer W in the peripheral supply step may be smaller than the amount of IPA discharged to the wafer W in the IPA liquid film forming step shown in FIG. 8B. Also, the IPA discharge time to the peripheral edge Wa of the wafer W may be short (for example, 2 seconds). As a result, an excessive increase in the thickness of the IPA liquid film at the peripheral portion Wa can be suppressed, and generation of particles on the wafer W after the drying process in the supercritical processing apparatus 3 can be prevented.

The present invention is not limited to the above-described embodiments and modifications as they are, and can be embodied by modifying constituent elements without departing from the gist of the invention at the implementation stage. Moreover, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above embodiments and modifications. Some components may be deleted from all the components shown in each embodiment and each modification. Furthermore, constituent elements of different embodiments and modifications may be combined as appropriate.

1 Substrate processing system 2 Cleaning device 3 Supercritical processing device 4 Control unit 20 Motor 23 Wafer holding mechanism 27 Rinse liquid nozzle 28 IPA nozzle 32 IPA supply unit 301 Processing vessel W Wafer Wa Periphery

Claims (11)

a liquid film forming step of supplying a processing liquid to the surface of the substrate while rotating the substrate at a first rotation speed to form a liquid film of the processing liquid covering the surface of the substrate;
a supply stop step of stopping the supply of the treatment liquid to the substrate while reducing the number of revolutions of the substrate to the first number of revolutions or less after the liquid film forming process;
a liquid amount adjusting step of reducing the liquid amount of the treatment liquid forming the liquid film by setting the number of revolutions of the substrate to a second number of revolutions larger than the first number of revolutions after the step of stopping the supply;
After the liquid amount adjusting step, a carrying-in step of carrying the substrate into the processing container with the liquid film of the processing liquid formed thereon;
After the carrying-in step, a pressurized processing fluid is supplied to the processing container, and the pressure in the processing container is maintained at a pressure at which the processing fluid maintains a critical state. a drying step of supplying the processing fluid to replace the processing liquid on the substrate with the processing fluid, discharging the processing fluid from the processing vessel, and drying the substrate. Method. 2. The substrate processing method according to claim 1, wherein rotation of said substrate is stopped in said supply stop step. 3. The substrate processing method according to claim 2, wherein in said supply stop step, after stopping rotation of said substrate, supply of said processing liquid is stopped. 2. The substrate processing method according to claim 1, wherein in said supply stop step, said substrate is rotated at a rotation speed equal to or lower than said first rotation speed. 5. The substrate processing method according to any one of claims 1 to 4, wherein in said liquid amount adjusting step, rotation of said substrate is stopped after a predetermined time has passed since the number of rotations of said substrate is increased. 6. The substrate processing method according to claim 1, further comprising , prior to said carrying-in step, a peripheral edge supply step of supplying said processing liquid to said peripheral portion of said substrate while rotating said substrate. . 7. The substrate processing method according to claim 6, wherein said edge supply step is performed after said liquid volume adjustment step. After the edge supplying step and before the carrying-in step, the supply of the processing liquid to the substrate is stopped and the amount of the processing liquid forming the liquid film is reduced while rotating the substrate. 8. The substrate processing method according to claim 7, further comprising a second liquid volume adjustment step of causing the liquid volume to be adjusted. 9. The substrate processing method according to claim 8, wherein in said second liquid amount adjusting step, said substrate is rotated at a rotation speed equal to or lower than said second rotation speed. When executed by a computer for controlling the operation of a substrate processing system, the computer controls the substrate processing system to perform the substrate processing method according to any one of claims 1 to 9 . A storage medium in which a program is recorded. a holding part that horizontally holds the substrate;
a rotation drive unit that rotates the holding unit;
a processing liquid supply unit that supplies processing liquid to the substrate held by the holding unit;
a control unit;
a liquid film forming step in which the control unit supplies the processing liquid to the surface of the substrate while rotating the substrate at a first rotation speed to form a liquid film of the processing liquid covering the surface of the substrate; After the liquid film forming step, a supply stop step of stopping the supply of the processing liquid to the substrate while reducing the rotation speed of the substrate to the first rotation speed or less, and after the supply stop step a liquid amount adjusting step of reducing the amount of the processing liquid forming the liquid film by setting the number of revolutions of the substrate to a second number of revolutions larger than the first number of revolutions; a loading step of loading the substrate into a processing container with the liquid film of the processing liquid formed thereon; after the loading step, supplying a pressurized processing fluid to the processing container, and supplying the pressurized processing fluid to the processing container to replace the processing liquid on the substrate with the processing fluid while maintaining the pressure in the processing container at a pressure at which the processing fluid maintains a critical state; and a drying step of discharging the processing fluid from the processing vessel and drying the substrate.

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