JP6843606B2 - Substrate processing equipment, substrate processing method and storage medium - Google Patents

Description

The present invention relates to a technique for drying the lower surface of a substrate in a substrate liquid processing apparatus that supplies a processing liquid to the lower surface of the substrate to perform liquid treatment.

In a substrate processing apparatus used for manufacturing a semiconductor device, a rinsing solution such as pure water is supplied to the lower surface of the substrate while rotating a substrate such as a semiconductor wafer in a horizontal position around the vertical axis, and the lower surface is rinsed. Sometimes. The "lower surface of the substrate" is a surface facing downward during processing, and may be both a front surface that is a device forming surface and a back surface that is a non-device forming surface.

After the rinsing treatment of the lower surface is completed, the substrate is rotated at high speed to shake off and dry. At this time, in order to promote drying and prevent the generation of water marks, a gas having a low humidity and preferably a low oxygen concentration, for example, nitrogen gas is supplied to the lower surface side of the substrate. A substrate liquid processing apparatus for performing the above processing is described in, for example, Patent Document 1.

In order to dry the substrate satisfactorily, it is preferable to first form a small circular drying region (drying core) in the center of the substrate, and gradually expand the outer peripheral edge of this drying region concentrically. By doing so, even if the particles are present in the liquid, the particles are driven to the outside of the substrate together with the liquid, so that it is possible to prevent the particles from remaining on the dried substrate.

Not limited to the device of Patent Document 1, when processing the lower surface of the substrate, the nozzle for discharging the liquid and gas supplied to the lower surface of the substrate is usually of the substrate due to restrictions on the device configuration and space. It is discharged from a position directly below the center. For this reason, it is relatively difficult to stably expand the dry region at a concentricly controlled speed. If the rate at which the dry area spreads is not properly controlled, the liquid film outside the dry area may be torn (droplets separated from the liquid film may be generated). If particles are present in the torn droplets, the particles reattach to the substrate after the droplets have dried.

Japanese Unexamined Patent Publication No. 2015-23130

An object of the present invention is to provide a technique capable of preventing the liquid film on the outside of the drying region from being torn to generate droplets when the lower surface of the substrate is dried.

According to one embodiment of the present invention, a substrate holding rotation mechanism that holds a substrate in a horizontal posture and rotates it around a vertical axis, and a substrate holding rotation mechanism that is held by the substrate holding rotation mechanism from below the substrate to the lower surface of the substrate. The treatment liquid supply unit that supplies the rinse liquid toward the central portion and the rinse liquid are supplied to the central portion of the lower surface of the substrate while rotating the substrate, and then the rinse liquid is supplied while the substrate is continuously rotated. When the substrate is stopped and the lower surface of the substrate is gradually dried from the central portion to the peripheral portion, the region where the rinse liquid film is present and the rinse liquid liquid film are formed on the lower surface of the substrate. When the radial distance from the center of the substrate at the boundary with the non-existing region is r and the angular velocity of the substrate is ω, at least when the r is larger than a certain threshold, the ω increases as the r increases. Provided is a substrate processing apparatus including a control unit that controls the rotation speed of the substrate by the substrate holding rotation mechanism so that

According to another embodiment of the present invention, a rinsing step of supplying a rinsing liquid to the central portion of the lower surface of the substrate while rotating the substrate in a horizontal posture around the vertical axis, and then rinsing while continuously rotating the substrate. A drying step of stopping the supply of the liquid and gradually drying the lower surface of the substrate from the central portion to the peripheral portion is provided, and when the drying step is being executed, the lower surface of the substrate is provided. When the radial distance from the center of the substrate at the boundary between the region where the rinse liquid film is present and the region where the rinse liquid film is not present is r and the angular velocity of the substrate is ω, Provided is a substrate processing method for controlling the rotation speed of the substrate so that the ω decreases as the radial distance r increases at least when the radial distance r is larger than a certain threshold value.

According to still another embodiment of the present invention, the substrate processing method controls the substrate processing apparatus when executed by a computer forming a control unit for controlling the operation of the substrate processing apparatus. A storage medium in which a program for executing the above is recorded is provided.

According to the above-described embodiment of the present invention, since the force for expanding the liquid film is suppressed in the vicinity of the peripheral edge of the substrate, it is possible to prevent the liquid film from being torn to generate droplets.

It is a schematic plan view which shows the whole structure of the substrate processing system which concerns on one Embodiment of the substrate processing apparatus of this invention. It is a schematic vertical sectional view of the processing unit included in the substrate liquid processing system of FIG. FIG. 5 is an enlarged cross-sectional view showing the vicinity of the processing liquid discharge port and the drying gas discharge port of the processing unit of FIG. It is a figure for demonstrating the progress of drying of the lower surface of a wafer. It is a figure for demonstrating the defect which occurs at the time of drying of the lower surface of a wafer. It is a graph explaining the control of the rotation speed of a wafer.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to the present embodiment. In the following, in order to clarify the positional relationship, the X-axis, Y-axis, and Z-axis that are orthogonal to each other are defined, and the positive direction of the Z-axis is defined as the 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 carriers C for accommodating a plurality of wafers W in a horizontal state are mounted on the carrier mounting portion 11.

The transport section 12 is provided adjacent to the carrier mounting section 11, and includes a substrate transport device 13 and a delivery section 14 inside. The substrate transfer device 13 includes a substrate holding mechanism for holding the wafer W. Further, the substrate transfer device 13 can move in the horizontal direction and the vertical direction and can rotate around the vertical axis, and transfers the wafer W between the carrier C and the delivery portion 14 by using the substrate 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 both sides of the transport unit 15.

The transport unit 15 includes a substrate transport device 17 inside. The substrate transfer device 17 includes a substrate holding mechanism for holding the wafer W. Further, the substrate transfer device 17 can move in the horizontal direction and the vertical direction and swivel around the vertical axis, and transfers the wafer W between the delivery unit 14 and the processing unit 16 by using the substrate holding mechanism. I do.

The processing unit 16 performs predetermined substrate processing on the wafer W transported by the substrate transport 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 that control various processes 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 storage medium readable by a computer, and may be installed from the storage medium in the storage unit 19 of the control device 4. Examples of storage media that can be read 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 mounted on the carrier mounting portion 11, and receives the taken out wafer W. Placed on Watanabe 14. The wafer W placed on the delivery section 14 is taken out from the delivery section 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

The wafer W carried into the processing unit 16 is processed by the processing unit 16, then carried out 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 delivery section 14 is returned to the carrier C of the carrier mounting section 11 by the substrate transfer device 13.

Next, the schematic configuration of the processing unit 16 will be described with reference to FIGS. 2 and 3. Unless otherwise specified, all the members appearing in FIG. 3 correspond to a rotating body as a geometric term.

As shown in FIG. 2, the processing unit 16 is supplied to the chamber 20, the substrate holding rotation mechanism 30 that holds and rotates the wafer W, the liquid discharge unit 40 that constitutes the processing liquid supply nozzle, and the wafer W. A recovery cup 50 for collecting the subsequent treatment liquid is provided.

The chamber 20 houses the substrate holding rotation mechanism 30, the liquid discharge unit 40, and the recovery cup 50. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20. The FFU 21 forms a downflow in the chamber 20.

The substrate holding rotation mechanism 30 is configured as a mechanical chuck that holds the wafer W by a mechanical clamping mechanism. The substrate holding rotation mechanism 30 includes a substrate holding portion 31, a rotating shaft 32, and a rotating motor (rotation driving unit) 33. The rotation speed of the rotary motor 33 can be continuously changed to an arbitrary value under the control of the control device 4. The rotary motor 33 rotationally drives the rotary shaft 32, whereby the wafer W held in the horizontal posture by the substrate holding portion 31 rotates around the vertical axis.

The substrate holding portion 31 has a disk-shaped base plate (plate-shaped body) 31a and a plurality of holding members 31b provided on the peripheral edge of the base plate 31a. The holding member 31b holds the peripheral edge of the wafer W. In one embodiment, some of the plurality of holding members 31b are movable support members that advance and retreat with respect to the peripheral edge of the wafer W to switch between gripping and releasing the wafer W, and the remaining holding members 31b are immovable. A holding member (for example, a support pin). The rotating shaft 32 is composed of a hollow tubular body extending in the vertical direction.

The rotating shaft 32 and the base plate 31a are connected by a connecting portion 34. The connecting portion 34 may be a separate part from the rotating shaft 32 and the base plate 31a, or may be an integral part with the rotating shaft 32 or the base plate 31a.

The liquid discharge portion 40 is formed as an elongated shaft-shaped member extending in the vertical direction as a whole. The liquid discharge portion 40 has a hollow cylindrical shaft portion 41 extending in the vertical direction and a head portion 42. The shaft portion 41 is inserted into the cylindrical cavity 32a inside the rotating shaft 32 of the substrate holding rotation mechanism 30. The shaft portion 41 and the rotating shaft 32 are concentric. A space as a gas passage 80 having an annular cross section is formed between the outer peripheral surface of the shaft portion 41 and the inner peripheral surface of the rotating shaft 32.

Drying gas is supplied to the gas passage 80 from the drying gas supply mechanism 74. The drying gas preferably has a low humidity so as to promote drying, and more preferably has a low oxygen concentration in order to prevent the generation of water marks. In the present embodiment, nitrogen gas, which is a gas having low humidity and low oxygen concentration, is used as the drying gas. Although the illustration and detailed description of the configuration of the drying gas supply mechanism 74 are omitted, for example, it is composed of a supply line connected to the gas supply source, an on-off valve and a flow rate control valve interposed in the supply line, and the like. To.

Inside the liquid discharge portion 40, there is a cylindrical cavity extending in the vertical direction. A treatment liquid supply pipe 43 (shown only in FIG. 3) is provided inside the cavity. The upper end of the processing liquid supply pipe 43 opens at the center of the upper surface of the head 42 of the liquid discharging portion 40, and discharges the processing liquid toward the center of the lower surface of the wafer W held by the substrate holding rotation mechanism 30. (Refer to the black arrow in FIG. 3) This is the liquid discharge port 43a.

A rinse liquid such as pure water (DIW) for cleaning the lower surface of the wafer W is supplied to the treatment liquid supply pipe 43 from the treatment liquid supply mechanism 72 (see FIG. 2). Although illustration and detailed description of the configuration of the processing liquid supply mechanism 72 are omitted, for example, it is composed of a supply line connected to the processing liquid supply source, an on-off valve and a flow rate control valve interposed in the supply line, and the like. To. The treatment liquid supply mechanism 72 may be configured so that the rinse liquid and a treatment liquid other than the rinse liquid, for example, a chemical liquid such as DHF, can be switched and supplied.

A cylindrical recess 34b communicating with the gas passage 80 is formed in the central portion of the upper surface of the connecting portion 34. Most of the lower side of the head 42 is housed in the recess 34b. The head portion 42 has a flange portion 42a that projects radially outward from the outer peripheral end of the recess 34a. The gas that has flowed upward in the gas passage 80 flows through the space 81 formed between the inner surface of the recess 34a and the surface of the head portion 42 facing the inner surface of the recess 34a, and further flows with the lower surface of the flange portion 42a. It flows through the gap 82 between the upper surface 34a of the connecting portion 34 and is ejected into the space 83 between the lower surface of the wafer W and the base plate 31a in a substantially horizontal direction toward the outside in the radial direction (white in FIG. 3). See arrow). That is, the gas injected from the outlet of the gap 82 is not directly blown toward the lower surface of the wafer W. The outlet of the gap 82 constitutes a gas injection section.

Further, even if the processing liquid supplied to the lower surface of the wafer W falls from the liquid discharge port 43a, the flange portion 42a can prevent the processing liquid from entering the gas passage 80 through the space 81. ..

As shown in FIG. 2, the recovery cup 50 is arranged so as to surround the substrate holding portion 31 of the substrate holding rotation mechanism 30, and collects the processing liquid scattered from the rotating wafer W. The recovery cup 50 has an immovable lower cup body 51 and an upper cup body 52 that can be raised and lowered between an ascending position (position shown in FIG. 2) and a lowering position. The upper cup body 52 moves up and down by the elevating mechanism 53. When the upper cup body 52 is in the lowered position, the upper end of the upper cup body 52 is located at a position lower than the wafer W held by the substrate holding rotation mechanism 30. Therefore, when the upper cup body 52 is in the lowered position, the wafer W is inserted between the substrate holding mechanism (arm) of the substrate conveying device 17 shown in FIG. 1 and the substrate holding rotation mechanism 30 which have entered the chamber 20. Can be delivered.

A discharge port 54 is formed at the bottom of the lower cup body 51. The collected treatment liquid and the atmosphere in the recovery cup 50 are discharged from the recovery cup 50 through the discharge port 54. A discharge pipe 55 is connected to the discharge port 54, and the discharge pipe 55 is connected to a factory exhaust system (not shown) in a depressurized atmosphere.

The downflow of clean air from the FFU 21 is drawn into the recovery cup 50 through the upper opening of the recovery cup 50 (upper cup body 52) and exhausted from the discharge port 54. Therefore, the air flow indicated by the arrow F is generated in the recovery cup 50.

The processing unit 16 is provided with a bifluid nozzle 61 that supplies a bifluid that is a mixed fluid of a mist of a rinse liquid and a gas (for example, nitrogen gas) on the upper surface of the wafer W held by the substrate holding rotation mechanism 30. May be good. The bifluid nozzle 61 is provided by a nozzle arm (not shown) at an arbitrary position between a position directly above the center of the wafer W and a position directly above the peripheral edge of the wafer W, and a standby position outside the wafer W (home). It can be positioned in the position).

The processing unit 16 may include a brush 62 that scrubs and cleans the upper surface of the wafer W held by the substrate holding rotation mechanism 30. The brush 62 can be positioned at an arbitrary position between the central portion of the wafer W and the peripheral edge portion of the wafer W, and at a standby position (home position) outside the wafer W by a nozzle arm (not shown).

Next, an example of the processing performed by the processing unit 16 will be described. Here, prior to the exposure process, a cleaning process for removing particles (for the purpose of preventing defocus during exposure) on the back surface (the surface on which the device is not formed) of the wafer W will be described. In this case, only pure water (DIW) is used as the treatment solution, and no chemical solution is used. Further, one of the 12 processing units 16 provided in FIG. 1 is replaced with a reverser (not shown) that turns the wafer over.

Before being carried into the processing unit 16, the substrate transfer device 17 holding the wafer W turned inside out by a reverser (not shown) enters the chamber 20 and passes the wafer W to the substrate holding portion 31 of the substrate holding rotation mechanism 30. The upper surface of the wafer W held by the substrate holding rotation mechanism 30 is the back surface on which the device is not formed, and the lower surface of the wafer W is the surface on which the device is formed. After that, the substrate holding mechanism (arm) exits the chamber 20, and the upper cup body 52 rises to the ascending position.

Next, the substrate holding rotation mechanism 30 rotates the wafer W. The wafer W continues to rotate until a series of processes on the wafer W are completed. In this state, pure water and nitrogen gas are supplied to the two-fluid nozzle 61, and a two-fluid composed of a droplet of pure water mistized by the nitrogen gas and a mixed fluid of the nitrogen gas is discharged from the two-fluid nozzle 61 to the wafer W It is sprayed toward. The bifluid nozzle 61 reciprocates between the central portion and the peripheral portion of the wafer W by a nozzle arm (not shown) while injecting the bifluid. As a result, the two-fluid cleaning is performed by removing the particles adhering to the upper surface of the wafer W by the energy of the two fluids.

After the completion of the two-fluid cleaning step, the supply of nitrogen gas is stopped while the supply of pure water to the two-fluid nozzle 61 is continued, so that the two-fluid nozzle 61 is not misted in the center of the upper surface of the wafer W. By supplying pure water, the upper surface of the wafer W is rinsed. After the completion of this rinsing treatment, the supply of pure water to the upper surface of the wafer W is stopped, and the wafer W is shaken off and dried.

When the treatment is performed with the back surface, which is the device non-forming surface, facing up, the back surface may be cleaned using a brush 62 instead of the two-fluid nozzle 61.

During the treatment of the upper surface of the wafer W (the back surface on which the device is not formed), particularly during the two-fluid cleaning and rinsing treatment in which bifluid or pure water is supplied to the surface of the wafer W, the lower surface of the wafer W. The wafer W is rinsed in order to prevent contamination (the back surface on which the device is not formed).

The rinsing treatment is performed by supplying pure water as a rinsing liquid from the liquid discharge port 43a of the liquid discharge unit 40 to the central portion of the lower surface of the rotating wafer W. The pure water supplied to the central portion of the lower surface of the wafer W flows while spreading outward in the radial direction due to centrifugal force, and scatters outward from the peripheral edge of the wafer W. At this time, the entire lower surface of the wafer W is covered with a liquid film of pure water. This liquid film of pure water blocks pure water containing particles that try to wrap around from the upper surface to the lower surface of the wafer W.

In order to prevent the rinsing liquid from wrapping around from the upper surface to the lower surface of the wafer W or from the lower surface to the upper surface, it is preferable to finish the rinsing treatment on the upper surface of the wafer W and the rinsing treatment on the lower surface of the wafer at the same time or substantially at the same time. That is, it is preferable to stop the supply of the rinse liquid on the upper surface of the wafer W and stop the supply of the rinse liquid on the lower surface of the wafer W almost at the same time.

The drying of the lower surface of the wafer W will be described below. It is preferable to reduce the oxygen concentration in the space between the wafer W and the base plate 31a of the substrate holding portion 31 so that water marks (which can cause particles) do not occur on the lower surface of the wafer W. Therefore, nitrogen gas is injected into the space from the outlet of the gap 82 between the lower surface of the flange portion 42a of the head portion 42 and the upper surface 34a of the connecting portion 34.

Since the particles adhering to the base plate 31a may fly up immediately after the start of the injection of the nitrogen gas, the injection of the nitrogen gas is started while the lower surface of the wafer W is covered with the liquid film of pure water. It is preferable to do so.

In drying the lower surface of the wafer W, first, the discharge of pure water from the liquid discharge port 43a of the liquid discharge unit 40 is stopped while the wafer W is rotated. Since the pure water existing on the lower surface of the wafer W is flowing toward the peripheral edge of the wafer W by centrifugal force, first, the liquid film LF of the pure water disappears at the center of the wafer W and the wafer W The surface (lower surface) of the surface is exposed. That is, a small circular drying region DA (also referred to as a drying core) is formed in the center of the wafer W (see also FIG. 4).

After that, the drying region DA expands with the passage of time, and finally the entire lower surface of the wafer W is dried. It is preferable that the dry region DA formed in the central portion of the lower surface of the wafer W smoothly spreads outward in the radial direction. More specifically, it is preferable that the boundary B between the liquid film LF and the dry region DA moves smoothly in the radial direction while maintaining a substantially circular shape.

If the moving speed of the boundary B is inappropriate, the liquid film LF may be torn and the droplet LD may be separated from the liquid film LF. The situation when this phenomenon occurs is schematically shown in FIG. Droplet shredding is likely to occur when the surface of the wafer is hydrophobic and when the surface of the wafer is a mixture of hydrophobic and hydrophilic regions, especially in the latter case. As a specific example, in a situation where a large number of quadrangular circuit patterns are formed on the surface of the wafer W in a matrix, many hydrophobic portions are present on the surface of the circuit pattern, and the region between the quadrangles is hydrophilic. May be. In this case, an event occurs in which droplets remain on the circuit pattern and then the droplets dry.

Particles can be present in the liquid film. The particles may have originally adhered to the wafer W, or may have been taken up into the liquid film LF after being wound up by the nitrogen gas injected from the outlet of the gap 82 as described above. .. When the droplets containing the particles are dried, the particles adhere to the surface of the wafer W. Droplets containing particles remain in the circuit pattern, and when they dry, they adversely affect the yield.

On the other hand, even if the particles are present in the liquid film, as described above, the boundary B between the liquid film LF and the dry region DA keeps a substantially circular shape and moves smoothly in the radial direction. If so, such a problem does not occur. That is, in this case, the particles in the liquid film move outward in the radial direction together with the liquid film, are discharged to the outside of the wafer W together with the liquid film, and do not remain on the surface of the wafer W.

Shredding of the liquid film LF is likely to occur when the boundary B is located near the peripheral edge WE of the wafer W. This is because the liquid film LF becomes thinner as the boundary B approaches the peripheral edge WE, and the force for expanding the liquid film LF increases. In a region where the liquid film is likely to be torn, it is preferable to suppress the rotation speed of the wafer W to be low to suppress the force for expanding the liquid film LF.

In the present embodiment, when the radial distance from the center O of the wafer W to the boundary B is r and the angular velocity of rotation of the wafer W is ω, at least the radial distance r is larger than a certain threshold value in the radial direction. The angular velocity ω of the wafer W is controlled so that the angular velocity ω decreases as the distance r increases, thereby suppressing the force for expanding the liquid film LF in the region where the liquid film is likely to be torn. When the radial distance r is relatively small, the liquid film is unlikely to be torn even if the angular velocity ω is relatively high. Therefore, in order to shorten the drying time, the angular velocity ω is increased in the region where the liquid film is unlikely to be torn, within the range where the liquid film is not torn.

The rotation speed of the wafer W (meaning the number of rotations per unit time, represented by, for example, the unit rpm (rotation speed / minute)) is a constant multiple of the angular velocity ω. Therefore, decreasing the angular velocity ω as the radial distance r increases is the same as decreasing the rotational speed of the wafer W as the radial distance r increases.

A specific control method will be described below.

[First control method]
In the first control method, when the radial distance r is _{larger than a certain threshold value r T1} , the radial distance r and the angular velocity are controlled so that the product rω of ω becomes constant. In this case, the peripheral speed of the wafer W at the radial position of the boundary B is the same regardless of the radial position of the boundary B. As a result, the force for expanding the liquid film LF is reduced even in the vicinity of the peripheral edge of the wafer W, so that the liquid breakage is less likely to occur. FIG. 6 shows an example of the relationship between the radial distance r and the rotation speed (rpm) of the wafer W (the rotation speed is equal to 60ω / 2π: the unit of ω is radians) when the first control method is adopted. It is shown by a white square in the graph of.

If an attempt is made to keep the product rω constant even when the radial distance setting r is small, the angular velocity ω (rotational speed) of the wafer W at that time becomes excessive, the wafer W vibrates, and the desired process cannot be executed. There is a fear. Further, when the radial distance setting r is small, that is, when the dry region DA is not so widened, the thickness of the liquid film LF near the boundary B is relatively thick, so that the possibility of liquid tearing is low. .. Therefore, the product rω when radial distance location r is equal to or smaller than the threshold r _T1, is smaller than the product rω when greater than the threshold value r _T1.

In actual practice, the angular velocity ω when the radial distance location r is less than the threshold r _T1, has the same constant value and the angular velocity ω when the radial distance location r is equal to the threshold r _T1. This facilitates rotation speed control. The threshold value r _T1 can be determined in consideration of the upper limit angular velocity ωmax (or upper limit rotation speed) of the wafer W and the thickness of the liquid film LF, which can be stably rotated without causing vibration of the wafer W. .. In the graph of FIG. 6, the wafer rotation speed corresponding to the upper limit angular velocity ωmax is set to 2500 rpm.

[Second control method]
In the second control method, when the radial distance r is _{larger than a certain threshold value r T2} ^{, the product rω 2} of the square of the radial distance r and the angular velocity ω is controlled to be constant. ^{In this case, regardless of the radial position of the boundary B, the centrifugal force (= mrω 2} ) received by the object on the wafer W, that is, the water forming the liquid film at the radial position of the boundary B is the same. As a result, the force for expanding the liquid film LF is reduced even in the vicinity of the peripheral edge of the wafer W, so that the liquid breakage is less likely to occur. FIG. 6 shows an example of the relationship between the radial distance r and the rotation speed (rpm) of the wafer W (the rotation speed is equal to 60ω / 2π: the unit of ω is radians) when the second control method is adopted. It is indicated by a black circle in the graph of. The angular velocity ω when the radial distance setting r is equal to or less than the threshold value r _T2 may be set in the same manner as in the case of the first control method.

In the present embodiment, the control of the rotation speed (angular velocity ω) of the wafer W is such that the relationship between the elapsed time from the start of drying and the radial distance r is grasped in advance, and the elapsed time from the start of drying. The rotation speed of the wafer W is controlled according to the time. The relationship between the elapsed time from the start of drying and the radial distance r can be grasped in advance by an experiment using a transparent circular substrate having the same shape as the wafer, or can be grasped by a simulation. If there is a space for providing an image pickup sensor or the like on the lower surface side of the wafer W due to the device structure, the sensor detects the radial position of the boundary B, that is, the radial distance r in real time during the cleaning process. It is also possible to do.

Drying of the upper surface of the wafer W is not described in detail herein. For example, while supplying a rinse liquid from a rinse nozzle (not shown) to a rotating wafer W, a drying gas such as nitrogen gas is supplied from a drying gas nozzle (not shown), and the radius at which the nitrogen gas collides with the wafer W. A known method of moving both the radial position PN and the radial position PR to the outside in the radial direction while maintaining the directional position PN radially inside the radial position PR where the rinse liquid collides with the wafer W. By using the above, good drying can be performed while controlling the moving speed of the boundary between the dry region and the liquid film. That is, the upper surface of the wafer W can be dried by a known method to prevent the liquid film from being torn and to prevent particles from remaining.

In the above embodiment, the cleaning treatment is performed with the back surface (device non-forming surface) of the wafer W facing upward and the front surface (device forming surface) of the wafer W facing downward, but the cleaning treatment is not limited to this. The cleaning treatment may be performed with the front surface of the wafer W facing upward and the back surface of the wafer W facing downward. Further, the upward surface of the wafer W may not be cleaned, and only the downward surface of the wafer W may be cleaned.

The substrate to be processed is not limited to the semiconductor wafer (wafer W), and if it is a circular substrate to be processed in a rotating state, it may be another type of substrate such as a glass substrate or a ceramic substrate. May be good.

W substrate (semiconductor wafer)
4 Control unit (control device)
30 Substrate holding rotation mechanism 31a Base plate 43a Processing liquid supply unit 82 Gas injection unit

Claims (12)

A board holding rotation mechanism that holds the board in a horizontal position and rotates it around the vertical axis,
A processing liquid supply unit configured to supply the rinse liquid only to the central portion of the lower surface of the substrate from below the substrate held by the substrate holding rotation mechanism.
The rinse liquid is supplied to the central portion of the lower surface of the substrate while rotating the substrate, and then the rinse liquid is discharged toward the central portion of the lower surface of the substrate while continuously rotating the substrate. When the supply of the rinse liquid is stopped and the lower surface of the substrate is gradually dried from the central portion to the peripheral portion, the region where the liquid film of the rinse liquid exists and the rinse on the lower surface of the substrate. When the radial distance from the center of the substrate at the boundary with the region where the liquid film does not exist is r and the angular velocity of the substrate is ω, at least when the radial distance r is larger than a certain threshold. By the substrate holding rotation mechanism , the angular velocity ω becomes smaller as the radial distance r becomes larger , and the liquid film of the rinse liquid outside the boundary is not torn to generate droplets. A substrate processing device including a control unit that controls the rotation speed of the substrate. The substrate according to claim 1, wherein the control unit controls the rotation speed of the substrate so that the product rω of the radial distance r and the angular velocity ω becomes constant when the radial distance r is larger than a certain threshold value. Processing equipment. The control unit controls the rotation speed of the substrate so that the product rω when the radial distance r is equal to or less than the threshold value is equal to or less than the product rω when the radial distance r is larger than the threshold value. , The substrate processing apparatus according to claim 2. The control unit maintains the angular velocity ω when the radial distance r is equal to or less than the threshold value at a constant value equal to the angular velocity ω when the radial distance r is equal to the threshold value. The substrate processing apparatus according to claim 2, which controls the rotation speed of the above. The control unit controls the rotation speed of the substrate so that ^{the product rω 2} of the square of the radial distance r and the angular velocity ω becomes constant when the radial distance r is larger than a certain threshold value. 1. The substrate processing apparatus according to 1. The control unit sets the rotation speed of the substrate so that the ^{product rω 2} when the radial distance r is equal to or less than the threshold value is equal to or less than the product rω ² when the radial distance r is larger than the threshold value. The substrate processing apparatus according to claim 5, which is controlled. The control unit maintains the angular velocity ω when the radial distance r is equal to or less than the threshold value at a constant value equal to the angular velocity ω when the radial distance r is equal to the threshold value. The substrate processing apparatus according to claim 5, which controls the rotation speed of the above. The substrate holding rotation mechanism has a base plate facing the substrate below the substrate held by the substrate holding rotation mechanism.
The substrate processing apparatus is oriented in a space between the substrate held by the substrate holding rotation mechanism and the base plate from below the central portion of the substrate in a direction substantially parallel to the surface of the substrate. The substrate processing apparatus according to any one of claims 1 to 7, further comprising a gas injection unit that injects a drying gas outward in the radial direction. A rinsing process in which the rinsing liquid is supplied only to the central portion of the lower surface of the substrate while rotating the substrate in a horizontal position around the vertical axis.
After that, while continuing to rotate the substrate, the supply of the rinse liquid is stopped from the state where the rinse liquid is discharged toward the central portion of the lower surface of the substrate, and the lower surface of the substrate is moved from the central portion to the peripheral portion. With a drying process that gradually dries toward
When the drying step is being performed, the radius from the center of the substrate at the boundary between the region where the rinse liquid film is present and the region where the rinse liquid film is not present on the lower surface of the substrate. When the directional distance is r and the angular velocity of the substrate is ω, at least when the radial distance r is larger than a certain threshold value, the angular velocity ω decreases as the radial distance r increases, and the angular velocity ω decreases. A substrate processing method for controlling the rotation speed of the substrate so that the liquid film of the rinse liquid outside the boundary is not torn and droplets are not generated. The substrate processing method according to claim 9, wherein the rotational speed of the substrate is controlled so that the product rω of the radial distance r and the angular velocity ω becomes constant when the radial distance r is larger than a certain threshold value. The substrate processing method according to claim 9, wherein the rotation speed of the substrate is controlled so that ^{the product rω 2} of the square of the radial distance r and the angular velocity ω becomes constant when the radial distance r is larger than a certain threshold value. .. The substrate processing according to any one of claims 9 to 11, wherein the computer controls the substrate processing apparatus when executed by a computer forming a control unit for controlling the operation of the substrate processing apparatus. A storage medium on which the program that executes the method is recorded.

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