JP2020004996A - Liquid processing method, substrate processing apparatus, and storage medium - Google Patents

Abstract

To provide a liquid processing method and the like capable of performing drying while suppressing collapse of a pattern on the surface of a substrate.SOLUTION: After supplying rinsing liquid for rinsing to a substrate for which a liquid treatment has been performed with a chemical liquid, drying liquid higher in volatility than the rinsing liquid is supplied to the center of the substrate to replace the rinsing liquid. Next, the supply position of the drying liquid is moved from the central portion of the substrate to the peripheral portion side, and a drying gas is supplied to a region where a liquid film of the drying liquid, which is formed at a central portion of the substrate as the supply position of the drying liquid moves, does not exist. Thereafter, the supply position of the drying gas to the substrate is moved from the central portion to the peripheral edge side of the substrate in accordance with the movement of the supply position of the drying liquid, and the substrate is dried.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for drying a substrate after a treatment with a treatment liquid has been performed.

  2. Description of the Related Art There is known a technique of sequentially switching and supplying a chemical solution, a rinsing liquid, and the like to a surface of a rotating substrate (for example, a semiconductor wafer (hereinafter, referred to as a wafer)) to perform liquid processing on the substrate. When these liquid treatments are completed, a highly volatile drying liquid (hereinafter referred to as “dry liquid”) such as IPA (Isopropyl Alcohol) is supplied to the rotating substrate, and the liquid remaining on the surface of the substrate is removed. After the replacement with the drying liquid, the substrate is dried by discharging the drying liquid. (For example, Patent Document 1)

  On the other hand, if the humidity in the processing container in which the liquid processing is performed is high, dew condensation may occur on the surface of the dried wafer. When the droplets adhering to the surface of the wafer during dew condensation are dried, a watermark is formed and the wafer after liquid treatment is contaminated, or the pattern of the surface of the wafer is affected by the effect of surface tension acting from the droplets. There is a risk of collapse.

JP 2007-36180 A: Claim 4, paragraph 0087, FIG.

  The present invention has been made under such circumstances, and its purpose is to carry out drying of a substrate while suppressing the collapse of the pattern on the surface of the substrate by controlling the humidity in the processing container. It is an object of the present invention to provide a liquid processing method, a substrate processing apparatus, and a storage medium storing the method.

The liquid processing method of the present invention is a liquid processing method for performing liquid processing on a substrate disposed in a processing container, and then drying the substrate.
In the center of the substrate, which is held horizontally in the processing container, collects and discharges the scattered processing liquid, and rotates around a vertical axis while being surrounded by a collection cup that is evacuated from the bottom side. A processing liquid supply step of supplying a processing liquid to perform liquid processing,
During the period in which the processing liquid is being supplied to the substrate, a low-humidity gas supply step of supplying a low-humidity gas that reduces the humidity in the processing container,
After stopping the processing liquid supplied to the substrate, a drying step of drying the substrate,
At a height position on the upper side of the collection cup, a humidity measurement value obtained by measuring the humidity at a position on the outer side of the collection cup was equal to or less than a preset humidity target value. The processing liquid to be supplied to the central portion of the substrate later is stopped.
Further, a liquid processing method of another invention is a liquid processing method of performing liquid processing on a substrate disposed in a processing container, and then drying the substrate.
A processing liquid supply step of performing a liquid processing by supplying a processing liquid to a central portion of the substrate in the processing container,
During the period in which the processing liquid is being supplied to the substrate, a low-humidity gas supply step of supplying a low-humidity gas that reduces the humidity in the processing container,
After stopping the processing liquid supplied to the substrate, a drying step of drying the substrate,
The humidity measurement value obtained by measuring the humidity in the processing container at a position near the upper side of the surface on which the processing liquid is supplied to the substrate and held by the substrate holding unit is a predetermined humidity target value. The processing liquid supplied to the central portion of the substrate is stopped after the following.

The liquid processing method may have the following configuration.
(A) After starting the low-humidity gas supply step, measurement of the humidity in the processing container is performed, and when the measured humidity value does not become equal to or less than the humidity target value, the processing liquid supply step is continued. Here, when the drying step is started after a predetermined drying start time has elapsed after the start of the low humidity gas supply step, the drying step is started after the drying start time has elapsed.
(B) measuring the humidity in the processing container after the start of the low-humidity gas supply step, and starting the drying step when the measured humidity value is equal to or less than the target humidity value. When the drying step is started after the start of the low-humidity gas supply step and after the elapse of a preset drying start time, when the humidity measurement value is equal to or less than the humidity target value, the drying start time Start the drying process before
(C) The timing at which the supply of the low-humidity gas is started in the low-humidity gas supply step is predicted to be after the start of the supply of the low-humidity gas to the processing container, and the measured humidity value will be equal to or less than the target humidity value. The predicted time until the target value reaching timing is grasped in advance, and is set by calculating backward from the target value reaching timing.
(D) The drying step includes an operation of moving a supply position of the drying liquid, which is the processing liquid, from the central portion side to the peripheral portion side of the substrate.

  According to the present invention, by controlling the humidity in the processing container, the substrate can be dried while suppressing the pattern on the surface of the substrate from collapsing.

It is a top view showing the outline of the substrate processing system provided with the processing unit concerning an embodiment of the invention. It is a vertical side view which shows the outline of the said processing unit. It is a top view of the processing unit. FIG. 3 is an explanatory diagram illustrating a gas supply and exhaust system to the processing unit. It is a process figure showing the flow of processing performed by the processing unit. It is a flowchart which shows the flow of operation | movement regarding the drying process of a wafer. 5 is a first time chart relating to processing executed by the processing unit. It is a 2nd time chart concerning the processing performed by the processing unit. It is a flow figure about the drying process of the wafer concerning a 2nd embodiment. 9 is a time chart of a process according to the second embodiment. FIG. 3 is an explanatory diagram illustrating a configuration example of a wafer heating mechanism.

  FIG. 1 is a diagram illustrating a schematic configuration of a substrate processing system according to the present embodiment. Hereinafter, in order to clarify the positional relationship, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined, and the positive direction of the Z axis is defined as a vertically upward direction.

  As shown in FIG. 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

  The loading / unloading station 2 includes a carrier mounting section 11 and a transport section 12. A plurality of substrates, in this embodiment, a plurality of carriers C that accommodates a semiconductor wafer (hereinafter, wafer W) in a horizontal state are mounted on the carrier mounting portion 11.

  The transport unit 12 is provided adjacent to the carrier mounting unit 11 and includes a substrate transport device 13 and a transfer unit 14 therein. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 13 is capable of moving in the horizontal direction and the vertical direction and turning around the vertical axis, and transfers the wafer W between the carrier C and the transfer unit 14 using the wafer holding mechanism. Do.

  The processing station 3 is provided adjacent to the transport unit 12. The processing station 3 includes a transport unit 15 and a plurality of processing units 16. The plurality of processing units 16 are provided side by side on the transport unit 15.

  The transfer section 15 includes a substrate transfer device 17 inside. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 17 is capable of moving in the horizontal direction and the vertical direction and turning around the vertical axis, and transfers the wafer W between the transfer unit 14 and the processing unit 16 using the wafer holding mechanism. I do.

  The processing unit 16 performs a predetermined substrate processing on the wafer W transferred by the substrate transfer device 17.

  Further, the substrate processing system 1 includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various types of processing executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the program stored in the storage unit 19.

  The program may be recorded on a computer-readable storage medium, and may be installed from the storage medium into the storage unit 19 of the control device 4. Examples of the storage medium readable by a computer include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

  In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading / unloading station 2 takes out the wafer W from the carrier C placed on the carrier placing portion 11 and receives the taken out wafer W. Placed on the transfer unit 14. The wafer W placed on the delivery unit 14 is taken out of the delivery unit 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

  The wafer W loaded into the processing unit 16 is processed by the processing unit 16, then unloaded from the processing unit 16 by the substrate transfer device 17, and placed on the delivery unit 14. Then, the processed wafer W mounted on the transfer unit 14 is returned to the carrier C of the carrier mounting unit 11 by the substrate transfer device 13.

  As shown in FIG. 2, the processing unit 16 includes a chamber 20, a substrate holding mechanism 30, a processing fluid supply unit 40, and a collection cup 50.

  The chamber 20 houses the substrate holding mechanism 30, the processing fluid supply unit 40, and the collection cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a down flow in the chamber 20.

  The substrate holding mechanism 30 includes a holding unit 31, a support unit 32, and a driving unit 33. The holding unit 31 holds the wafer W horizontally. The support portion 32 is a member extending in the vertical direction. The support portion 32 is rotatably supported at the base end by the driving portion 33, and horizontally supports the holding portion 31 at the tip end. The drive section 33 rotates the support section 32 around a vertical axis. The substrate holding mechanism 30 rotates the support portion 31 supported by the support portion 32 by rotating the support portion 32 by using the driving portion 33, thereby rotating the wafer W held by the support portion 31. .

  The processing fluid supply unit 40 supplies a processing fluid to the wafer W. The processing fluid supply unit 40 is connected to a processing fluid supply source 70.

  The collection cup 50 is disposed so as to surround the holding unit 31, and collects the processing liquid scattered from the wafer W by the rotation of the holding unit 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the processing liquid collected by the recovery cup 50 is discharged from the drain port 51 to the outside of the processing unit 16. An exhaust port 52 for discharging gas supplied from the FFU 21 to the outside of the processing unit 16 is formed at the bottom of the collection cup 50.

The processing unit 16 provided in the above-described substrate processing system corresponds to the substrate processing apparatus according to the embodiment of the present invention. The processing unit 16 has a configuration in which IPA that is a drying liquid (drying liquid) is supplied to the rotating wafer W after the processing with the chemical liquid or the rinsing liquid, and then the wafer W is dried. The chemical, the rinsing liquid, and the drying liquid correspond to the processing liquid of the present embodiment.
Hereinafter, the configuration will be described with reference to FIG.

  In the processing unit 16 of the present example, the processing fluid supply unit 40 described above includes a chemical solution nozzle 413 that supplies a chemical solution to the wafer W held by the substrate holding mechanism 30, and DIW (Deionized Water) that is a rinse solution. A DIW nozzle 412 that supplies IPA and an IPA nozzle 411 that supplies IPA.

  In this example, the above-described nozzles 411 to 413 are provided at the distal end of the common first nozzle arm 41. The base end side of the first nozzle arm 41 is located above the central portion of the wafer W held by the holding portion (substrate holding portion) 31 and at a position retracted laterally from the position above the wafer W. Are connected to a guide rail 42 for moving these nozzles 411 to 413. The guide rail 42 is provided with a driving unit 421 for moving the first nozzle arm 41. Here, in FIG. 3, the first nozzle arm 41 retracted to the side is shown by a solid line, and the first nozzle arm 41 that has entered above the central portion of the wafer W is shown by a broken line.

  The chemical liquid nozzle 413 is connected to the chemical liquid supply source 73 via an opening / closing valve V3. One or more chemicals are supplied from the chemical supply source 73 according to the purpose of processing the wafer W. In the present embodiment, one type of chemical is described. The chemical liquid is supplied from the chemical liquid nozzle 413 via the opening / closing valve V3.

The DIW nozzle 412 is connected to the DIW supply source 72 via the opening / closing valve V2. DIW is supplied from the DIW nozzle 412 via the opening / closing valve V2.
The DIW nozzle 412, the opening / closing valve V2, and the DIW supply source 72 correspond to the rinsing liquid supply unit of this example.

The IPA nozzle 411 is connected to the IPA supply source 71 via the opening / closing valve V1. From the IPA nozzle 411, a processing liquid supplied to the wafer W immediately before the IPA supply, for example, IPA, which is a drying liquid having a higher volatility than DIW, is supplied via the valve V1.
The IPA nozzle 411, the opening / closing valve V1, and the IPA supply source 71 correspond to the drying liquid supply unit of this example.

Further, as shown in FIG. 3, the processing unit 16 includes an N ₂ nozzle 431 for supplying a nitrogen (N ₂ ) gas, which is an inert gas, as a drying gas to the surface of the wafer W after the supply of the drying liquid. It has.
_{N 2} nozzle 431 of the present embodiment is provided on the distal end portion of the different second nozzle arm 43 and the first nozzle arm 41 described above etc. IPA nozzle 411 is provided. The base end side of the second nozzle arm 43 is located between the position above the central portion of the wafer W held by the holding portion 31 and the position retracted laterally from the position above the wafer W. It is connected to a guide rail 44 for moving the _two nozzles 431. The guide rail 44 is provided with a driving unit 441 for moving the second nozzle arm 43. In FIG. 3, the second nozzle arm 43 retracted to the side is indicated by a solid line, and the second nozzle arm 43 that has entered above the center of the wafer W is indicated by a broken line (common with the first nozzle arm 41 described above). (Broken line).
N ₂ nozzle 431 is connected to the _{N 2} supply source 74 via an on-off valve V4.

Furthermore, the processing unit 16 according to the present embodiment includes, in a chamber 20 that is a processing container, clean air (atmosphere) taken in from the FFU 21 and CDA (Clean Dry Air) that is a low-humidity gas having a lower humidity than the clean air. ) Can be switched and supplied.
Hereinafter, an air supply and exhaust system for the chamber 20 will be described with reference to FIG. 4, illustration of the nozzle arms 41 and 43 provided with the nozzles 411 to 414 and their driving mechanisms (guide rails 42 and 44 and driving units 421 and 441) are omitted in FIG.

  In the processing unit 16 of this example, the FFU 21 shown in FIG. 2 is arranged in more detail, for example, at the ceiling of the substrate processing system 1 shown in FIG. (See FIG. 4).

As shown in FIG. 4, each processing unit 16 is supplied with a gas supply line 211 for receiving clean air distributed and supplied from the FFU 21 and a clean air received from the gas supply line 211 into the chamber 20 for cleaning. And a gas diffusion unit 213 for forming a downflow of air.
The gas supply line 211 is provided between the FFU 21 and each processing unit 16.

  The gas diffusion unit 213 is provided so as to cover the ceiling surface of the chamber 20 constituting the processing unit 16, and forms a space above the ceiling surface for diffusing the clean air supplied from the gas supply line 211. A large number of gas supply holes 214 are provided on the entire ceiling surface of the chamber 20 covered by the gas diffusion unit 213, and clean air is supplied into the chamber 20 via the gas supply holes 214.

Further, CDA having a lower humidity than the clean air can be supplied to the gas supply line 211 and the gas diffusion unit 213 by switching to the clean air supplied from the FFU 21.
That is, as shown in FIG. 4, a switching valve 215 is provided on the gas supply line 211 of each processing unit 16, and a CDA supply line 222 for supplying CDA is connected to the switching valve 215. Have been. An on-off valve V5 is interposed in the CDA supply line 222, and the upstream side thereof is connected to a CDA supply source 221.

  As the CDA, clean air obtained by removing particles and impurities using an air filter or the like is further subjected to an adsorption treatment, a cooling treatment, or the like to remove water.

For example, when the target humidity value in the chamber 20 during the period of supplying the CDA is set to 1% by mass of the amount of saturated steam (0 ° C., a standard state converted value of 1 atm. The same applies hereinafter), the CDA supply source 221 is used. Supplies CDA with a humidity lower than 1%.
The CDA supply line 222 and the CDA supply source 221 and the gas supply line 211 and the gas diffusion unit 213 on the downstream side of the switching valve 215 during the period of receiving the CDA correspond to the low-humidity gas supply unit in this example.

The clean air and CDA supplied into the chamber 20 from the gas diffusion unit 213 flow down in the chamber 20 as downflow, and a part of the air flows into the collection cup 50 and is provided at the bottom of the collection cup 50. The air is exhausted toward the external exhaust portion 23 through the exhaust port 52 described above.
Further, the clean air and CDA that have not flowed into the collection cup 50 are exhausted to the external exhaust unit 23 through, for example, a chamber exhaust port 201 provided at the bottom of the chamber 20.

  The processing unit 16 having the above configuration is further provided with a hygrometer 24 as a humidity measuring unit for measuring the humidity in the chamber 20. For example, the hygrometer 24 includes a sensor unit 241 that performs humidity measurement, and a main body unit 242 that converts the humidity in the chamber 20 measured by the sensor unit 241 into an electric signal and outputs the electric signal to the control unit 18. ing. As long as the humidity meter 24 can measure the humidity in the chamber 20, there is no particular limitation on a specific humidity measurement method, and for example, a resistance change type or a capacitance type can be adopted.

  As shown in FIG. 4, the sensor unit 241 is inserted into the chamber 20 via, for example, a side wall. In the chamber 20, the sensor unit 241 is desirably arranged at a position where it is possible to detect that the gas in the chamber 20 in contact with the surface of the wafer W is below the target humidity value over the entire surface of the wafer W. In this respect, the sensor unit 241 is disposed at a height position on the upper side of the collection cup 50 and on the outer side of the collection cup 50, which is a position radially outside the substrate held by the holding unit 31. ing.

  At the position on the outer side of the collection cup 50, the gas in the chamber 20 tends to stay, and the humidity tends to be higher than the upper surface of the wafer W held by the substrate holding mechanism 30. Therefore, when the humidity measurement value measured on the outer side of the collection cup 50 is equal to or lower than the target humidity value, it can be said that the gas atmosphere below the target humidity value is also established on the upper surface side of the wafer W. . Therefore, the sensor unit 241 of the present example does not interfere with the transfer operation of the wafer W between the substrate transfer device 17 and the substrate holding mechanism 30 and that the upper surface side of the wafer W is lower than the target humidity. It is placed in a position where it can be checked.

  In the processing unit 16 described above, the movement of each of the nozzles 411 to 413 and 431 shown in FIG. 3 to the upper position of the wafer W and the position retracted from the upper position, The control of the supply / stop of the fluid and the control of the flow rate, and the switching of the clean air / CDA supplied to the chamber 20 from the FFU 21 or the CDA supply source 221 shown in FIG.

Further, the processing unit 16 of the present example has a function of adjusting the progress of the processing performed on the wafer W based on the result of measuring the humidity in the chamber 20 with the hygrometer 24.
Hereinafter, the operation performed by the processing unit 16 will be described in detail with reference to FIGS.

First, an outline of the processing performed on the wafer W will be described with reference to FIGS.
When the wafer W loaded into the processing unit 16 by the substrate transport mechanism 17 is held by the holding pins 311 provided in the holding unit 31, the first nozzle arm 41 that has been retracted to the side is moved above the wafer W. Then, the chemical liquid nozzle 413 and the DIW nozzle 412 are arranged at a position above the center of the wafer W. Thereafter, the wafer W is rotated at a predetermined rotation speed, a chemical solution is supplied from the chemical solution nozzle 413, and a chemical solution process is performed (FIG. 5A).

  When the processing with the predetermined chemical solution is completed, the supply of the chemical solution from the chemical solution nozzle 413 is stopped while the wafer W after the chemical solution process is being rotated, and the DIW is supplied from the DIW nozzle 412 to perform the rinsing process (FIG. 5 (b)). After the rinsing process is performed for a predetermined time, the supply of DIW from the DIW nozzle 412 is stopped while the wafer W is being rotated, and the IPA is supplied from the IPA nozzle 411 to replace the DIW (FIG. 5C). ).

  At this time, IPA is supplied from the IPA nozzle 411 toward the center of the wafer W. The supplied IPA spreads over the surface of the wafer W by the action of the centrifugal force, and a liquid film of IPA is formed on the entire surface of the wafer W. By forming the IPA liquid film in this manner, DIW supplied to the surface of the wafer W during the rinsing process can be mixed and replaced with IPA.

  When the DIW on the surface of the wafer W is replaced with the IPA, the IPA is extended to a side (for example, a position moved about several tens of mm from the center of the wafer W in the radial direction) from the position where the IPA is supplied to the center of the wafer W. The nozzle 411 is moved. As a result, from the center of the wafer W to which the IPA supplied from the IPA nozzle 411 does not reach, the IPA flows out by the action of the centrifugal force, and a region where no liquid film exists (hereinafter, also referred to as a “core”) is formed. (FIG. 5D, first drying process).

The second nozzle arm 43 retracted to the side enters the upper side of the wafer W in accordance with the movement operation of the IPA nozzle 411 described above, and the N ₂ nozzle 431 is arranged at a position above the center of the wafer W. I do. Then, when the above-described core is formed, N ₂ gas is supplied toward the core to promote drying of the surface of the wafer W.

Thereafter, the rotation of the wafer W, IPA supply from IPA nozzle 411, while continuing the supply of _{N 2} gas from the _{N 2} nozzle 431, these nozzles 411 and 431 to the peripheral portion from the central portion of the wafer W Is moved in the opposite direction, for example. In the scanning operation at this time, each nozzle arm is set so that the supply position of the N ₂ gas from the N ₂ nozzle 431 is located closer to the center of the wafer W in the radial direction than the supply position of the IPA from the IPA nozzle 411. The movement operations of 41 and 43 are controlled.

With the scanning operation of the supply position of the IPA, the liquid film of the IPA is pushed away to the peripheral edge side of the wafer W and removed, and an area where the liquid film is not formed is widened. Further, with the scanning operation of the N ₂ gas supply position, the N ₂ gas is blown onto the surface of the wafer W after the IPA liquid film has been swept away, and the drying of the area is completed (FIG. 5E). Second drying process).

When the supply position of the IPA reaches the peripheral edge of the wafer W, the supply of the IPA from the IPA nozzle 411 is stopped. Then the supply position of the N ₂ gas when it reaches the periphery of the wafer W, to stop the supply of N ₂ gas from the N ₂ nozzle 431.
In the processing of the wafer W shown in FIGS. 5A to 5E, FIGS. 5A to 5C correspond to the processing liquid supply step of this example, and the processing of the IPA liquid film on the surface of the wafer W is performed. The first and second drying processes after the operation of forming a core by removing a part (the operation of stopping the drying liquid supplied to the central portion of the wafer W) correspond to a drying process (FIGS. 5D and 5D). e)).

By the above operation, the DIW is replaced and removed from the entire surface of the wafer W by the IPA, and a dried wafer W can be obtained.
After the drying of the wafer W is completed, the nozzle arms 41 and 43 are retracted to the side, the rotation of the wafer W is stopped (operation before unloading), and the processed wafer W is processed by the substrate transfer device 17 into a processing unit. Remove from 16. Thus, a series of processing on the wafer W in the processing unit 16 is completed.

  Here, in the processing unit 16 of the present example, the gas supplied to the chamber 20 is clean air and low-humidity gas in accordance with the contents of the processing described with reference to FIGS. Switching between a certain CDA. Further, the drying process is not started unless the humidity in the chamber 20 becomes equal to or less than a preset humidity target value.

Hereinafter, with reference to FIGS. 6 to 8, the switching of the gas supplied to the chamber 20 and the progress of the processing performed on the wafer W based on the humidity measured in the chamber 20 using the hygrometer 24 will be described. The details of the operation for adjusting the value will be described.
Here, FIG. 6 is a flowchart showing the flow of the operation for adjusting the progress of the processing on the wafer W. 7 and 8 are time charts during the processing period of the wafer W. Of the two time charts, FIG. 7 shows a case where the humidity inside the chamber 20 has reached the target humidity value at the time when the preset switching timing has elapsed, and FIG. The case where the humidity target value is reached is shown. The switching timing is a point in time when a switching operation is performed to stop the supply of IPA to the central portion of the wafer W and switch to the drying process (however, as shown in FIG. Is continuing). FIGS. 7 and 8A show the contents of the processing corresponding to FIGS. 5A to 5E described above, and FIGS. 7 and 8B show the types of gas supplied to the chamber 20. Is shown. FIGS. 7 and 8C show changes over time in the measured humidity value in the chamber 20.

  According to the time charts of FIGS. 7A and 7B, clean air is supplied from the FFU 21 to the chamber 20 during the chemical solution treatment (FIG. 5A). Next, after the process for the wafer W is switched to the rinsing process (FIG. 5B), the gas changing operation is performed. However, the gas changing operation to the chamber 20 is performed until the preset gas changing timing (1) elapses. Continue supplying clean air. Next, when the gas change timing (1) has elapsed, a gas change operation for changing the gas supplied to the chamber 20 to CDA during the rinsing process is performed (low humidity gas supply step). With the switching of the gas, the value measured by the hygrometer 24 gradually decreases (FIG. 7C).

  Here, the timing of executing the gas changing operation is not limited to the case where the timing is set during the execution period of the rinsing process as in the example illustrated in FIG. 7C. For example, the time from the start of the supply of CDA to the time when the humidity in the chamber 20 becomes equal to or lower than the target humidity value (the predicted time when the humidity is predicted to be equal to or lower than the target humidity value) is obtained by a preliminary experiment or the like. It is preferable to perform the gas change operation based on time. As a specific example, the change timing of the gas change operation can be set by calculating the predicted time back from the switching timing. As described above, if the humidity is equal to or lower than the target humidity value by the time the gas changing operation is started and the drying process is started, the gas changing operation may be started after the IPA supply is started. Note that the gas change operation may be performed at a timing earlier than in the above-described example, but there is a possibility that the CDA consumption will increase. It is also conceivable that the start of the gas change operation is further advanced, and the gas change operation is started during the execution of the chemical treatment.However, for example, when the chemical is an etchant, the in-plane uniformity of the etching is deteriorated. It is not preferable because there is a possibility that it may occur.

After performing the rinsing process for a predetermined time, the processing liquid supplied to the wafer W is switched to IPA, and a liquid film of IPA is formed on the surface of the wafer W (see FIG. 5C and FIG. 7A). ).
The subsequent operation will be described with reference to the flowchart of FIG. 6 (start of FIG. 6). IPA supply is started, and a liquid film of IPA is formed on the surface of the wafer W (Step S101 in FIG. 6).

  Thereafter, when the supply of the IPA to the central portion of the wafer W is stopped (by moving the IPA nozzle 411 to form a core at the central portion of the wafer W) and the switching timing for performing the operation for switching to the drying process has elapsed. Then, it is determined whether or not the measured humidity value obtained by measuring the humidity in the chamber 20 by the hygrometer 24 is equal to or less than a preset humidity target value (for example, 1% by mass) (step S102).

As shown in FIG. 7C, if the measured humidity value in the chamber 20 has reached the target humidity value before the switching timing (Step S102 in FIG. 6; YES), the IPA nozzle 411 is moved. Then, the drying process for forming the above-described core is started (step S103). Then, after performing the drying process by the method described with reference to FIGS. 5D and 5E, the process proceeds to the operation of unloading the processed wafer W (end in FIG. 6).
For example, at a predetermined gas change timing (2) after the completion of the drying process of the wafer W, the gas supplied to the chamber 20 is switched to the clean air from the FFU 21 (FIG. 7A).

On the other hand, as shown in FIG. 8C, when the measured humidity value in the chamber 20 does not reach the target humidity value even after the switching timing has elapsed (Step S102 in FIG. 6; NO, S104; NO). ), IPA continuous supply for continuing IPA supply is performed (step S105). By this operation, the state in which the liquid film of IPA is formed on the surface of the wafer W is maintained until the measured humidity value in the chamber 20 reaches the target humidity value.
For reference, FIG. 8 (c) shows the change with time of the humidity measurement value in FIG. 7 (c) by a dashed line.

  Then, when the measured humidity value in the chamber 20 reaches the target humidity value (Step S102 in FIG. 6; YES), the operation after the drying process is executed by the same procedure as that of FIG. 7 described above (FIG. 6). Step S103 → End, FIG. 8).

  On the other hand, when the humidity measurement value in the chamber 20 does not reach the humidity target value even after a preset duration has elapsed since the IPA supply was continued (step S102 in FIG. 6; NO → Step S104; YES), the IPA continuous supply is terminated, and the drying process is executed in an atmosphere where the humidity in the chamber 20 is higher than the target humidity value (step S106). The duration is set to, for example, about one minute to several minutes from the start of the IPA supply continuation.

Here, with respect to the wafer W that has been subjected to the drying process in a high-humidity atmosphere, formation of a watermark or collapse of a pattern due to dew condensation on the surface of the wafer W may occur.
Therefore, for the processing unit 16, an alarm indicating that the humidity in the chamber 20 has not reached the target humidity value within a predetermined time (in this example, the time from the start of the IPA supply to the elapse of the continuous time). Is issued (step S107). As the alarm, an alarm sound may be issued from a speaker (not shown) provided in the substrate processing system 1, or an alarm screen may be displayed on an operation screen (not shown) of the substrate processing system 1. Further, the wafer W that has been subjected to the drying process in a humid atmosphere is attached with information to that effect to isolate the wafer W from the product wafer W accommodated in the carrier C and to prevent the occurrence of watermarks and pattern collapse. Or perform additional inspections to confirm the situation.

  According to the processing unit 16 according to the present embodiment described above, the following effects can be obtained. The drying process of the wafer W is started after the measured humidity value obtained by measuring the humidity of the chamber 20 in which the liquid processing is performed becomes equal to or less than a preset humidity target value. As a result, it is possible to reduce the influence on the wafer W (water mark formation and pattern collapse) caused by drying the wafer W in a state where the replacement of the chamber 20 by the CDA is insufficient.

Here, the method of adjusting the timing of executing the drying process based on the result of measuring the humidity in the chamber 20 using the hygrometer 24 is not limited to the example described with reference to FIGS.
For example, as shown in FIG. 9, when the humidity in the chamber 20 becomes equal to or less than the target humidity value, the start timing of the drying process may be advanced without waiting for the elapse of the switching timing (step S101 → step S102 in FIG. 9). YES → Step S103, FIG. 10).

  Here, in FIG. 6 described above, an example in which the start timing of the drying process is delayed has been described, and FIG. 9 shows an example in which only the start timing of the drying process is moved forward. Therefore, in this example, the setting of the duration is omitted, and when the switching timing comes, the drying process is started regardless of whether the humidity in the chamber 20 has reached the target value (Step S104 ′ in FIG. 9). ; YES → step S106). Thereafter, an alarm may be issued in the same manner as in the processing after the continuation time in FIG. 6 (step S107).

Further, as in the example described with reference to FIGS. 6 to 8 and FIGS. 9 to 10, it is not essential to perform timing management in which “switch timing and duration” from IPA supply to drying processing are set in advance. .
For example, the switching timing of the process from the IPA supply to the drying process may be appropriately changed based only on the criterion of “whether or not the humidity in the chamber 20 has become equal to or less than the humidity target value”.

In addition to these, the hygrometer 24 provided in the processing unit 16 performs a drying step (FIG. 5D) after performing a processing liquid supply step using the processing liquid (FIGS. 5A to 5C). It can be used for other than the determination of the start timing of (e)).
For example, during a standby period in which the processing of the wafer W is not performed in the processing unit 16, the gas supplied to the chamber 20 is switched from clean air to CDA, and the humidity measured by the hygrometer 24 is as scheduled (for example, switching timing). A confirmation operation for confirming whether or not the humidity becomes equal to or lower than the target humidity value may be performed by the elapse of the time corresponding to. At this time, the substrate holding mechanism 30 is rotated without holding the wafer W, or the dummy wafer W is used so that the inside of the chamber 20 becomes the same state as when the wafer W is processed, as shown in FIGS. ) May be executed.

  In the above-described confirmation operation, when the temporal change of the humidity target value is different from the normal value, the CDA supply system (the CDA supply line 222, the CDA supply source 221, and the switching valve during the CDA receiving period) is used as the low humidity gas supply unit. In some cases, equipment troubles in the gas supply line 211 and the gas diffusion section 213 on the downstream side of the chamber 215 and the exhaust system of the chamber 20 (the exhaust port 52, the chamber exhaust port 201, and the exhaust section 23) can be grasped in advance.

  In addition, the sensor unit 241 may be provided at a position different from the position on the outer side of the collection cup 50. For example, the sensor unit 241 of the hygrometer 24 may be configured to be movable between an upper position of the wafer W held by the substrate holding mechanism 30 and a position retracted from the upper position. In this case, for example, when the wafer W is transferred to the substrate holding mechanism 30, the sensor unit 241 is retracted to the retreat position, and when the start of the drying process is determined, the sensor unit 241 is moved to the upper side of the wafer W, The drying step can be started after confirming that the atmosphere near the surface of W is equal to or lower than the target humidity value.

Next, a heating mechanism for supplying a heating gas to the back surface of the wafer W will be described with reference to FIG. For example, in a drying process using a volatile drying liquid such as IPA, the heat of vaporization is deprived of the drying liquid, and the temperature of the wafer W may decrease, thereby causing dew condensation. Therefore, in the conventional processing unit 16, as shown in FIGS. 3, 4 and 11, a gap is formed between the holding unit 31 and the holding unit 31 by using a plurality of holding pins 311 provided on the peripheral edge of the holding unit 31. Thus, the temperature of the wafer W is prevented from lowering by holding the wafer W and supplying DIW heated to, for example, about 60 to 80 ° C. to the gap.
However, if DIW is used to heat the wafer W during the drying process, the mixed solution of IPA and DIW discharged from the wafer W must be treated as wastewater, which increases the load of the wastewater treatment. .

  Thus, in the example shown in FIG. 11, the wafer W is heated using the same substance as the drying liquid supplied to the upper surface side of the wafer W, in this example, the heating steam of IPA. That is, a heating gas flow path 321 is formed in the support portion 32, and the heating gas flow path 321 is connected to the heating IPA supply source 81 via the vaporization section 811 and the on-off valve V 6. The heating IPA supply source 81 may be common to the IPA supply source 71 connected to the IPA nozzle 411, or may be configured separately. The vaporizing section 811 includes, for example, a heating section (not shown) for obtaining IPA vapor heated to 100 ° C., and IPA that is supplied in a liquid state and is heated to be a gas, and then heated to 100 ° C. And a heating space (not shown) that flows. The heating gas flow path 321, the vaporizing section 811, the on-off valve V6, and the heating IPA supply source 81 constitute a heating gas supply section.

According to the configuration described above, the IPA supply position is moved, and after the removal of the IPA, the IPA vapor for heating is supplied to the lower surface side of the wafer W to which the N ₂ gas is blown, thereby removing the IPA. The temperature of the wafer W in the region can be heated to a temperature higher than the dew point temperature of moisture. In particular, since the IPA vapor can be heated to a temperature higher than about 82 ° C., which is the boiling point of IPA, the effect of heating the wafer W is high. Further, even if the heated IPA is cooled and liquefied in contact with the wafer W or the like, the heated IPA is collected via the collection cup 50 together with the liquid IPA discharged from the upper surface side of the wafer W, and is reused as relatively high-purity IPA. be able to. In addition, an effect of suppressing an increase in humidity in the chamber 20 can be obtained as compared with the case where the wafer W is heated using the heating DIW.

  As another example, it is not essential that the processing unit 16 performs the drying process on the wafer W using the drying liquid. For example, for a wafer W that has been subjected to a hydrophobizing treatment using dilute hydrofluoric acid or a silylating agent, after the rinsing treatment, the supply of the rinsing liquid is stopped without performing replacement with the drying liquid, and the drying processing is performed. May be. Even in such a drying process, a low-humidity gas such as CDA is supplied into the chamber 20 and the drying process is performed after confirming that the humidity in the chamber 20 is equal to or lower than a predetermined humidity target value. Thus, the effect of suppressing the occurrence of dew condensation on the surface of the wafer W can be obtained.

  The gas that can be used as the low humidity gas may be an inert gas such as a nitrogen gas instead of the above-described CDA. On the other hand, the liquid that can be used as the drying liquid is not limited to IPA, and acetone, HFE (hydrofluoroether), or the like can be used.

W Wafer 16 Processing unit 20 Chamber 21 FFU
211 Gas supply line 213 Gas diffusion unit 221 CDA supply source 222 CDA supply line 24 Hygrometer 241 Sensor unit 242 Main unit 31 Holding unit 40 Processing fluid supply unit

The present liquid processing method is a step of supplying a rinsing liquid for rinsing cleaning to the substrate after being rotated about a vertical axis while being held horizontally, and after the liquid processing with the chemical liquid is performed,
Stopping the supply of the rinsing liquid, and supplying a drying liquid having a higher volatility than the rinsing liquid to the central portion of the rotating substrate to replace the rinsing liquid with the rinsing liquid;
A step of moving the supply position of the drying liquid to the rotating substrate from a central portion side of the substrate to a peripheral portion side,
A step of supplying a drying gas to an area where a liquid film of the drying liquid is not formed, which is formed in a central portion of the rotating substrate with the movement of the supply position of the drying liquid,
A step of moving the supply position of the drying gas to the rotating substrate in accordance with the movement of the supply position of the drying liquid, moving the substrate from a central portion side to a peripheral portion side, and drying the substrate. Including .

The liquid processing method may have the following configuration.
(A) The step of moving the supply position of the drying liquid and the step of moving the supply position of the drying gas are performed in parallel. At this time, the supply position of the drying liquid and the supply position of the drying gas are moved in opposite directions. Further, the supply positions of the drying liquid and the drying gas are moved so that the supply position of the drying gas is located closer to the radial center of the substrate than the supply position of the drying liquid. .
(B) the rotating substrate is disposed in a processing container, and the method includes a step of supplying a low-humidity gas for reducing humidity in the processing container. At this time, the step of supplying the low-humidity gas is performed during a period from a step of moving a supply position of the drying liquid to a step of drying the substrate.

This technology moves the supply position of the drying liquid and the supply position of the drying gas supplied to the region where the liquid film of the drying liquid does not exist from the center side to the peripheral side of the substrate. The substrate can be dried while suppressing the pattern from collapsing.

Claims (12)

  A step of rotating around a vertical axis while being held horizontally, and supplying a rinse liquid for rinse cleaning to the substrate after the liquid processing with the chemical liquid is performed;
  Stopping the supply of the rinsing liquid, and supplying a drying liquid having a higher volatility than the rinsing liquid to the central portion of the rotating substrate to replace the rinsing liquid with the rinsing liquid;
  A step of moving the supply position of the drying liquid to the rotating substrate from a central portion side of the substrate to a peripheral portion side,
  A step of supplying a drying gas to an area where a liquid film of the drying liquid is not formed, which is formed in a central portion of the rotating substrate with the movement of the supply position of the drying liquid,
  A step of moving the supply position of the drying gas to the rotating substrate in accordance with the movement of the supply position of the drying liquid, moving the substrate from a central portion side to a peripheral portion side, and drying the substrate. Liquid treatment method including.   The liquid processing method according to claim 1, wherein the step of moving the supply position of the drying liquid and the step of moving the supply position of the drying gas are performed in parallel.   The liquid processing method according to claim 2, wherein a supply position of the drying liquid and a supply position of the drying gas are moved in opposite directions.   The supply position of the drying liquid and the drying gas is moved such that the supply position of the drying gas is located closer to the radial center of the substrate than the supply position of the drying liquid. 4. The liquid treatment method according to 2 or 3.   5. The liquid processing method according to claim 1, wherein the rotating substrate is disposed in a processing container, and includes a step of supplying a low-humidity gas that reduces humidity in the processing container.   The liquid processing method according to claim 5, wherein the step of supplying the low-humidity gas is performed during a period from a step of moving a supply position of the drying liquid to a step of drying the substrate.   A board holding unit configured to hold the board horizontally and to be rotatable about a vertical axis,
  For the substrate to be processed, a chemical liquid nozzle for supplying a chemical liquid for performing liquid processing of the substrate,
  A rinsing liquid nozzle for supplying a rinsing liquid for rinsing the chemical liquid to the substrate to be processed held by the substrate holding unit,
  A drying liquid nozzle provided so as to be able to supply a drying liquid having a higher volatility than the rinsing liquid while moving between the central part side and the peripheral part side of the substrate to be processed,
  A drying gas nozzle provided to be able to supply a drying gas while moving between a central portion side and a peripheral portion side of the substrate to be processed,
  And a control unit,
  Supplying the rinsing liquid from the rinsing liquid nozzle to the substrate on which liquid processing has been performed by supplying the chemical liquid from the chemical liquid nozzle by rotating the substrate to be processed; and Stopping the supply of the liquid and supplying the drying liquid from the drying liquid nozzle to the center of the rotating substrate to replace the rinsing liquid; and drying the rotating substrate. Moving the drying liquid nozzle that supplies the drying liquid from the central part side of the substrate to be processed to the peripheral part side, and forming the drying liquid nozzle in the central part of the rotating substrate with the movement of the drying liquid nozzle. Supplying the drying gas from the drying gas nozzle to a region where the liquid film of the dried drying liquid does not exist, and supplying the drying gas to the rotating substrate. The drying gas nozzle to be supplied is moved from the central part side to the peripheral part side of the substrate in accordance with the movement of the drying liquid nozzle, and the step of drying the substrate is controlled. , Substrate processing equipment.   8. The substrate processing apparatus according to claim 7, wherein the control unit is configured to move the drying liquid nozzle and the drying gas nozzle in parallel. 9.   The substrate processing apparatus according to claim 8, wherein the control unit is configured to move the drying liquid nozzle and the drying gas nozzle in opposite directions.   The controller, the drying gas nozzle and the drying gas nozzle, the drying liquid nozzle and the drying gas nozzle, so that the position of the drying liquid nozzle is located closer to the center in the radial direction of the substrate to be processed, the drying liquid nozzle and the drying gas nozzle The substrate processing apparatus according to claim 8, wherein the apparatus is configured to be moved.   The substrate processing according to any one of claims 7 to 10, wherein the substrate holding unit has a low-humidity gas supply unit that is disposed in a processing container and supplies a low-humidity gas that reduces humidity in the processing container. apparatus.   The control unit is configured to control execution of the step of supplying the low-humidity gas from the low-humidity gas supply unit during a period including a step of moving the drying liquid nozzle to a step of drying the substrate. The substrate processing apparatus according to claim 11, wherein

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