CN114570556A

CN114570556A - Liquid processing method and liquid processing apparatus

Info

Publication number: CN114570556A
Application number: CN202111394120.0A
Authority: CN
Inventors: 宫窪祐允; 高桥哲平
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2020-12-01
Filing date: 2021-11-23
Publication date: 2022-06-03
Also published as: JP2022087527A; KR20220077073A

Abstract

The invention provides a liquid treatment method and a liquid treatment apparatus, which can inhibit the generation of flocculent blocks caused by coating liquid thrown off from a substrate. The liquid treatment method comprises the following steps: a step of supplying a coating liquid to the front surface of the substrate; and a step of forming a coating film on the front surface by diffusing the coating liquid on the front surface of the substrate, wherein in the step of forming the coating film, the solvent of the coating liquid is started to be continuously supplied from a solvent supply portion to a peripheral portion of the front surface of the substrate from before the coating liquid reaches the peripheral portion, and the step of forming the coating film is continued at least until the step of forming the coating film is ended.

Description

Liquid processing method and liquid processing apparatus

Technical Field

The present invention relates to a liquid processing method and a liquid processing apparatus.

Background

In the substrate processing apparatus of patent document 1, a disk-shaped cup-shaped base is disposed below the rotary holding unit, and an annular middle cup is attached to the cup-shaped base. The cup-shaped base has a through hole formed in the center thereof, and a rotation shaft of the motor is disposed so as to pass through the through hole. A plurality of vent holes are formed in the cup-shaped base along the through hole. The ventilation hole is disposed at a position corresponding to the inner side of the outer peripheral portion of the rotation holding portion. When the substrate held by the rotation holding portion rotates at a high speed, air is supplied to the back surface side of the substrate through the vent hole, and the space on the back surface side of the substrate side is prevented from becoming negative pressure, whereby the mist can be prevented from spreading to the back surface side of the substrate.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 11-283899

Disclosure of Invention

Technical problem to be solved by the invention

The technique of the present invention can suppress generation of a flocculent block caused by a coating liquid thrown off from a substrate.

Technical solution for solving technical problem

One embodiment of the present invention includes: a step of supplying a coating liquid to the front surface of the substrate; and a step of forming a coating film on the front surface of the substrate by diffusing the coating liquid on the front surface, wherein in the step of forming the coating film, the solvent of the coating liquid is started to be continuously supplied from a solvent supply portion to a peripheral portion of the front surface of the substrate from before the coating liquid reaches the peripheral portion, and at least the step of forming the coating film is continued to be ended.

Effects of the invention

According to the present invention, generation of a cotton-like lump due to the coating liquid thrown off from the substrate can be suppressed.

Drawings

FIG. 1 is a view schematically showing a filament-like portion formed by a coating liquid spun off a substrate.

Fig. 2 is a vertical sectional view showing a schematic configuration of a resist coating apparatus as a liquid processing apparatus according to the present embodiment.

Fig. 3 is a cross-sectional view showing a schematic configuration of a resist coating apparatus as a liquid processing apparatus according to the present embodiment.

Fig. 4 is a flowchart for explaining an example of a wafer processing flow in the resist coating apparatus.

Fig. 5 is a view schematically showing a state of the wafer W at each step included in the wafer processing.

Fig. 6 is a view showing an example of the position of the solvent supply nozzle when the organic solvent is continuously supplied.

Fig. 7 is a graph showing the results of the confirmation test 1.

Fig. 8 is a graph showing the results of the confirmation test 3.

Description of the reference numerals

1 resist coating apparatus

20 rotating holding part

43 resist liquid supply nozzle

46 solvent supply nozzle

100 control part

Inclined part of B edge

W wafer

We rim

Ws on the front side.

Detailed Description

In a manufacturing process of a semiconductor device or the like, a coating process is performed in which a coating liquid such as a resist liquid is applied to a substrate such as a semiconductor wafer (hereinafter, referred to as a "wafer") to form a coating film.

Among the above-described coating processes, a so-called spin coating method is widely used, in which a coating liquid is supplied to a front surface (front surface) of a rotating wafer, the coating liquid is diffused over the front surface of the wafer by a centrifugal force, and the coating liquid is applied to the entire front surface of the wafer. In a liquid processing apparatus for performing coating by a spin coating method, a container called a cup is provided in order to prevent a coating liquid scattered from a surface of a rotating wafer from being scattered to the periphery. Further, for the purpose of forming a desired air flow on the surface of the coating film, the air is discharged from the bottom of the cup-shaped body.

However, in recent years, a coating film having a large thickness is sometimes required to be formed on the surface of a wafer. When a coating film having a large thickness is formed, for example, a high-viscosity coating liquid is used. When the spin coating method is used with a high viscosity coating liquid, a part of the coating liquid supplied to the front surface of the wafer is spun off from the peripheral edge of the front surface of the wafer, and at this time, as shown in fig. 1, a wire-shaped portion H extending in a wire shape radially outward from the peripheral edge of the front surface of the wafer W is formed. The wire portion H is further extended longer for the rotation operation of the wafer W, and is dried and solidified. The solidified filament portions H are entangled with each other to form a flocculent mass. The lint-like pieces are broken from the wafer W during the processing, for example, and become a factor of clogging an exhaust path in the cup-shaped body of the liquid processing apparatus and hindering the exhaust. When the exhaust pressure is increased due to the inhibition of the exhaust from the cup of the liquid processing apparatus, for example, a desired air flow cannot be formed on the surface of the coating film on the wafer, and a film thickness distribution having a uniform film thickness in the plane cannot be obtained.

Therefore, the technique of the present invention suppresses generation of a floc caused by the coating liquid spun off from the wafer.

Hereinafter, a liquid processing method and a liquid processing apparatus according to the present embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description thereof is omitted.

(liquid treatment apparatus)

Fig. 2 and 3 are a longitudinal sectional view and a cross sectional view showing a schematic configuration of a resist coating apparatus 1 as a liquid processing apparatus of the present embodiment.

As shown in fig. 2, the resist coating apparatus 1 includes a process container 10 whose inside can be sealed. A wafer W loading/unloading port (not shown) as a substrate is formed in a side surface of the processing container 10.

A rotation holding unit 20 for holding and rotating the wafer W is provided in the processing container 10. Specifically, the rotary holder 20 holds the wafer W and rotates the wafer W around a rotation axis perpendicular to the front surface of the wafer W. Further, the rotation holding portion 20 includes: a spin chuck 21 configured to be rotatable in a state of holding the wafer W; and a chuck driving section 22 having an actuator such as a motor and rotating the spin chuck 21. The spin chuck 21 is configured to be rotatable at various speeds (rotational speeds) by a chuck drive section 22. The chuck drive unit 22 is provided with a lifting drive mechanism having an actuator such as a cylinder, for example, and the spin chuck 21 is configured to be able to be lifted and lowered by the lifting drive mechanism.

In addition, a cup 30 is provided in the processing container 10. The cup body 30 includes: an outer cup 31 disposed outside the spin chuck 21 so as to surround the wafer W held by the spin chuck 21; and an inner cup 32 located on the inner peripheral side of the outer cup 31. The outer cup 31 receives and collects liquid scattered or dropped from the wafer W.

As shown in fig. 3, a rail 40 extending in the Y direction (the left-right direction in fig. 3) is formed on the negative X direction (the lower direction in fig. 3) side of the outer cup 31. The rail 40 is formed, for example, from the outside of the outer cup 31 on the negative Y-direction (left direction in fig. 3) side to the outside on the positive Y-direction (right direction in fig. 3) side. The rail 40 is provided with 2

arms

41 and 42.

A resist liquid supply nozzle 43 as a coating liquid supply unit is supported by the first arm 41. The resist liquid supply nozzle 43 supplies a resist liquid as a coating liquid to the front surface of the wafer W held by the spin chuck 21. The resist liquid discharged and supplied from the resist liquid supply nozzle 43 has a high viscosity of 100cp or more. The first arm 41 is movable on the rail 40 by a nozzle driving unit 44 having an actuator such as a motor as a moving mechanism of the resist liquid supply nozzle 43. Thus, the resist liquid supply nozzle 43 can be moved from the standby portion 45 provided on the outer side of the outer cup 31 in the negative Y direction to above the center portion of the wafer W in the outer cup 31. Further, the first arm 41 is movable up and down by the nozzle driving unit 44, and the height of the resist liquid supply nozzle 43 can be adjusted.

A resist liquid supply source (not shown) is connected to the resist liquid supply nozzle 43. A supply pipe (not shown) connecting the resist liquid supply nozzle 43 and the supply source of the resist liquid is provided with a supply equipment group (not shown) for controlling the supply of the resist liquid from the supply source of the resist liquid to the resist liquid supply nozzle 43. The supply apparatus group includes, for example, a supply valve for switching supply and stop of the resist liquid, a flow rate adjustment valve for adjusting a flow rate of the resist liquid, and the like.

A solvent supply nozzle 46 as a solvent supply unit is supported by the second arm 42. The solvent supply nozzle 46 supplies the solvent of the coating liquid to the front surface of the wafer W held by the spin chuck 21. The solvent supplied from the solvent supply nozzle 46 is, for example, an organic solvent such as a diluent. The second arm 42 is movable on the rail 40 by a nozzle driving unit 47 having an actuator such as a motor as a moving mechanism for the solvent supply nozzle 46. Thus, the solvent supply nozzle 46 can be moved from the standby portion 48 provided on the outer side of the outer cup 31 in the positive Y-direction to above the peripheral edge of the wafer W in the outer cup 31. The second arm 42 is movable up and down by the nozzle driving unit 47, and the height of the solvent supply nozzle 46 can be adjusted.

A supply source (not shown) of an organic solvent is connected to the solvent supply nozzle 46. A supply pipe (not shown) connecting the solvent supply nozzle 46 and the supply source of the organic solvent is provided with a supply equipment group (not shown) for controlling the supply of the organic solvent from the supply source of the organic solvent to the solvent supply nozzle 46. The supply equipment group includes, for example, a supply valve for switching supply and stop of the organic solvent, and a flow rate control valve for controlling the flow rate of the organic solvent.

The solvent supply nozzle 46 is provided so as to be inclined such that the organic solvent discharged from the solvent supply nozzle 46 is directed toward the downstream side in the rotational direction of the wafer W rotated by the rotation holding portion 20. In other words, the solvent supply nozzle 46 is provided obliquely so that the discharge direction D of the organic solvent from the solvent supply nozzle 46 (see the thick line arrow in fig. 3) is directed to the downstream side of the rotation direction of the wafer W rotated by the rotation holding unit 20 in a plan view.

As shown in fig. 2, a cleaning liquid supply nozzle 50 is provided in a portion between the inner cup 32 and the spin chuck 21. The cleaning liquid supply nozzle 50 supplies a cleaning liquid to the back surface of the wafer W held by the spin chuck 21. The cleaning liquid supplied from the cleaning liquid supply nozzle 50 is, for example, an organic solvent such as a diluent, and may be the same as the solvent supplied from the solvent supply nozzle 46.

A cleaning liquid supply source (not shown) is connected to the cleaning liquid supply nozzle 50. A supply pipe (not shown) connecting the cleaning liquid supply nozzle 50 and the supply source of the cleaning liquid is provided with a supply device group (not shown) for controlling the supply of the cleaning liquid from the supply source of the cleaning liquid to the cleaning liquid supply nozzle 50. The supply device group includes, for example, a supply valve for switching between supply and stop of the cleaning liquid and a flow rate adjustment valve for adjusting a flow rate of the cleaning liquid.

A cylindrical wall 31a is provided at the lower part of the outer cup 31, and a cylindrical wall 32a is provided at the lower part of the inner cup 32. A gap constituting the exhaust passage d is formed between these

wall bodies

31a, 32 a. Further, a curved passage is formed below the inner cup 32 by a horizontal member 33a having an annular shape in plan view, a cylindrical outer vertical member 33b and inner vertical member 33c, and a bottom member 33d having an annular shape in plan view and located at the bottom. The curved passage constitutes a gas-liquid separation section.

A drain port 34 for discharging the collected liquid is formed in the bottom member 33d at a portion between the wall body 31a and the outer peripheral vertical member 33b, and a drain pipe 35 is connected to the drain port 34.

On the other hand, an exhaust port 36 for exhausting the atmosphere around the wafer W is formed in the bottom surface member 33d at a portion between the outer peripheral vertical member 33b and the inner peripheral vertical member 33c, and an exhaust pipe 37 is connected to the exhaust port 36.

Further, in the cup-shaped body 30, a collecting member 60 is provided so as to close an upper portion of the exhaust path d provided between the wall body 31a of the outer cup-shaped body 31 and the wall body 32a of the inner cup-shaped body 32. The collecting member 60 is a member for collecting a material obtained by solidifying the resist liquid in a filament shape, and is made of metal such as SUS. Further, the trap member 60 closes the exhaust path d as described above, but has the opening 61 communicating in the vertical direction, so that exhaust can be performed through the opening 61. The collecting member 60 is, for example, a member having an annular shape in plan view, and the openings 61 are provided so as to be arranged at equal intervals in the circumferential direction. The collecting member 60 is disposed in the cup 30 so that the upper surface thereof is substantially horizontal, for example.

The resist coating apparatus 1 described above is provided with the control unit 100 as shown in fig. 2. The control unit 100 is a computer having, for example, a CPU, a memory, and the like, and includes a program storage unit (not shown). The program storage unit stores programs for implementing various processes in the resist coating apparatus 1. For example, the program storage unit stores a program for outputting control signals to the supply device group provided for each of the chuck drive unit 22, the

nozzle drive units

44 and 47, the resist solution supply nozzle 43, the solvent supply nozzle 46, and the cleaning solution supply nozzle 50 to realize a wafer process to be described later. The program may be a program recorded in a non-transitory computer-readable storage medium, and the program may be installed from the storage medium to the control unit 100. Part or all of the program may also be implemented by dedicated hardware (circuit board).

(example of wafer processing)

Next, an example of wafer processing in the resist coating apparatus 1 will be described with reference to fig. 4 to 6. Fig. 4 is a flowchart for explaining an example of a wafer processing flow in the resist coating apparatus 1. Fig. 5 is a view schematically showing the state of the wafer W at each step of the wafer processing. Fig. 6 is a diagram showing an example of the position of the solvent supply nozzle 46 when the organic solvent is continuously supplied, which will be described later. The following wafer processing is performed under the control of the control unit 100.

First, as shown in fig. 4, the wafer W is carried into the processing chamber 10, and placed on the spin chuck 21 of the spin holder 20 and held by suction (step S1).

Next, the resist solution is supplied from the resist solution supply nozzle 43 to the front surface of the wafer W (step S2).

Specifically, the wafer W held by the spin chuck 21 is rotated at a rotation speed ω 1 (for example, 50 to 150rpm), and the resist solution is supplied from the resist solution supply nozzle 43 to the center of the front surface Ws of the wafer W as shown in fig. 5 a. Thus, a pool of resist solution (pool of liquid) is formed in the central region of the front surface Ws of the wafer W.

Next, the wafer W is rotated, the resist solution is spread on the front surface of the wafer W by the centrifugal force generated by the rotation, a resist film is formed on the front surface, and the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W (step S3).

Specifically, in step S2, after the resist solution pool is formed and the supply of the resist solution from the resist solution supply nozzle 43 is stopped, the wafer W is rotated at a rotation speed ω 2 (for example, 400 to 1000rpm) higher than the rotation speed ω 1. Due to the centrifugal force at this time, the coating liquid on the front surface Ws of the wafer W spreads to the peripheral edge as shown in fig. 5 (B).

The organic solvent starts to be continuously supplied from the solvent supply nozzle 46 to the peripheral edge We of the front surface Ws of the wafer W before the diffused resist solution reaches the peripheral edge We. Specifically, for example, immediately after the supply of the resist solution from the resist solution supply nozzle 43 is stopped, the continuous supply of the organic solvent from the solvent supply nozzle 46 to the peripheral portion We is started. Thus, at the time when the diffused resist liquid reaches the peripheral edge portion We and thereafter, the organic solvent can be made to exist in the peripheral edge portion We, in other words, the peripheral edge portion We can be wetted with the organic solvent in advance. Therefore, the resist solution reaching the peripheral edge We of the front surface Ws of the wafer W is mixed with the organic solvent, and the viscosity thereof is lowered. If the viscosity of the resist solution on the peripheral edge We of the front surface Ws of the wafer W decreases as described above, the above-described filament-like portion H (see fig. 1) is difficult to form when the resist solution is spun off from the front surface peripheral edge. Therefore, in the diffusion step and the subsequent steps in step S3, the generation of the flocs due to the resist liquid thrown off from the wafer W can be suppressed.

The "peripheral edge portion" refers to a portion of the front surface of the wafer W other than the device formation region outside the semiconductor device formation region, for example, a portion of the front surface of the wafer W within a distance of 1mm from the peripheral edge.

When the organic solvent is continuously supplied to the peripheral edge We of the front surface Ws of the wafer W, the position of the solvent supply nozzle 46 is, for example, as shown in fig. 6, a position at which a liquid column P formed by the organic solvent discharged from the solvent supply nozzle 46 comes into contact with the edge bevel portion B of the peripheral edge of the front surface of the wafer W.

After the resist film is formed, the wafer W is further rotated, the resist film is dried, and the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W (step S4).

Specifically, in step S2, after the resist solution is diffused over the entire front surface (except for the peripheral edge) of the wafer W, that is, after a resist film covering the entire front surface (except for the peripheral edge) of the wafer W is formed, the wafer W is rotated at a rotation speed ω 3 (for example, 1000 to 1500rpm) higher than the rotation speed ω 2. By rotating the wafer W at the rotation speed ω 3 for a predetermined time, the resist film on the front surface of the wafer W can be dried.

During this drying, the resist solution on which the resist film is formed may reach the peripheral edge portion of the front surface of the wafer W and be thrown off from the peripheral edge portion of the front surface of the wafer W, thereby forming the above-described filament portion H (see fig. 1). In contrast, in this example, in the drying step, as shown in fig. 5 (C), the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral edge We of the front surface Ws of the wafer W. Specifically, the continuous supply of the organic solvent is continued until the end of the drying step. Therefore, when the resist solution forming the resist film reaches the peripheral edge portion of the front surface of the wafer W, the resist solution is mixed with the organic solvent and the viscosity thereof is lowered. If the viscosity of the resist solution for forming the resist film on the peripheral edge portion of the front surface of the wafer W is reduced as described above, the above-described thread-like portion is difficult to form when the resist solution is thrown off from the peripheral edge portion of the front surface (see fig. 1). Therefore, in this drying step, the generation of the floc due to the resist liquid thrown off from the wafer W can be suppressed.

After the drying step, the coating liquid is removed from a predetermined region on the peripheral edge side of the front surface of the wafer W by the organic solvent supplied from the solvent supply nozzle 46 (step S5).

Specifically, after the organic solvent is continuously supplied from the solvent supply nozzle 46 in the drying step of step S4, the removal of the coating liquid in a predetermined region on the peripheral side of the front surface of the wafer W (hereinafter also referred to as "peripheral edge removal of the front surface of the wafer") is continued, that is, the solvent is continuously supplied from the solvent supply nozzle 46 without interruption when the peripheral edge removal of the front surface of the wafer is shifted. When the peripheral edge of the front surface of the wafer is removed, the wafer W is rotated at a rotation speed ω 4 substantially equal to the rotation speed ω 2.

The liquid column P when the organic solvent is continuously supplied to the peripheral edge portion of the front surface of the wafer W started in step S3 is set in the region where the peripheral edge portion of the front surface of the wafer W is removed at the landing position of the wafer W. In the case where the region from which the peripheral edge is removed includes a region different from the solvent supply position up to step S4, the solvent supply nozzle may supply the organic solvent while moving in the horizontal direction of the wafer W so that the landing position of the liquid column P does not change in the region.

The continuous supply of step S3 and step S4 may be performed without changing the flow rate of the organic solvent in the removal of the peripheral edge of the front surface of the wafer in step S5, for example.

In step S5, the coating liquid spreading over the back surface of the wafer W is also removed.

Specifically, the cleaning liquid is discharged from the cleaning liquid supply nozzle 50 to the back surface of the wafer W rotating at the rotation speed ω 4 as described above. Thus, the cleaning liquid is supplied to the portion of the back surface of the wafer W on the outer peripheral side of the portion from which the cleaning liquid discharged from the cleaning liquid supply nozzle 50 is discharged, and the coating liquid spreading from the peripheral edge of the front surface of the wafer W to the back surface is also removed. The cleaning liquid supplied to the back surface of the wafer W is thrown off from the peripheral edge portion of the back surface of the wafer W and supplied to the collecting member 60. Therefore, when the cotton-like clumps or the like are collected by the collecting member 60, the cotton-like clumps or the like can be dissolved and removed.

The release position of the cleaning liquid from the cleaning liquid supply nozzle 50 to the back surface of the wafer W is located inward of the release position of the organic solvent from the solvent supply nozzle 46 to the front surface of the wafer W, and is spaced inward in the radial direction by 80mm to 120mm, for example, from the peripheral edge of the wafer W.

Thereafter, the wafer W is detached from the spin chuck 21 and sent out from the processing container 10 (step S6).

This completes a series of wafer processes in the resist coating apparatus 1.

As described above, the wafer processing of the present embodiment includes: a step of supplying a resist solution to the front surface of the wafer W; a step of forming a resist film on the front surface of the wafer W by diffusing the supplied resist solution on the front surface by rotating the wafer W (hereinafter also referred to as "diffusion forming step"). In the wafer processing, the supply of the organic solvent from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W is started and continued at least until the diffusion forming step is completed before the resist solution reaches the peripheral edge portion. Therefore, in the diffusion forming step and the subsequent steps, the resist solution on the peripheral edge We of the front surface Ws of the wafer W is mixed with the organic solvent supplied from the solvent supply nozzle 46, and the viscosity is lowered, so that the above-described filament-like portion H (see fig. 1) is difficult to form when the resist solution is spun off from the front surface peripheral edge. Therefore, according to the wafer processing of the present embodiment, the generation of the floc due to the resist liquid thrown off from the wafer W can be suppressed in the diffusion forming step and the subsequent steps. As a result, the occurrence of troubles due to the cotton-like clumps can also be suppressed.

In the wafer processing according to the present embodiment, in the steps necessary for forming the resist film (for example, the diffusion forming step), only the continuous supply of the organic solvent from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W is performed in parallel, and therefore, the time required for the entire processing is not increased, and the throughput is not reduced.

In addition, it is also conceivable that the organic solvent is not supplied from the solvent supply nozzle 46 but supplied from the cleaning liquid supply nozzle 50 which supplies the organic solvent as the cleaning liquid to the back surface of the wafer W for continuous supply of the organic solvent at the time of the diffusion forming step or the like. However, in this case, even if the organic solvent from the cleaning liquid supply nozzle 50 can spread to the peripheral edge portion of the front surface of the wafer W, the area of the portion cooled by contacting the organic solvent of the wafer W becomes excessively large, and the film thickness distribution is greatly affected. Therefore, in the present embodiment, the organic solvent is continuously supplied from the solvent supply nozzle 46 located above the wafer W, that is, located on the front surface side of the wafer W, in the diffusion forming step or the like.

In the wafer processing of the present embodiment, the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W in the resist film drying step performed after the diffusion forming step. Therefore, the generation of the flocs due to the resist solution thrown off from the wafer W in the drying step can be further suppressed. Further, by continuing the continuous supply of the organic solvent until the end of the drying step of the resist film, the generation of the flocs can be further suppressed.

In the present embodiment, the position of the solvent supply nozzle 46 when the organic solvent is continuously supplied to the peripheral edge portion of the front surface of the wafer W is, for example, a position at which a liquid column P formed by the organic solvent discharged from the solvent supply nozzle 46 comes into contact with the edge inclined portion B of the peripheral edge portion of the front surface of the wafer W. Accordingly, the portion of the organic solvent supplied to the peripheral portion of the front surface of the wafer W on the side of the edge inclined portion B, that is, the portion on the outer peripheral side moves along the edge inclined portion toward the outer periphery. On the other hand, the inner peripheral portion of the organic solvent supplied to the peripheral edge portion of the front surface of the wafer W is pulled toward the edge inclined portion B by the surface tension of the organic solvent itself, and the centrifugal force generated by the rotation of the wafer W acts to move toward the outer peripheral portion in the same manner. Therefore, the organic solvent from the solvent supply nozzle 46 can be suppressed from moving from the supply position in the front surface of the wafer W to the inner peripheral side. As shown in fig. 6, the liquid column P may be located inward of the peripheral edge of the wafer W. In other words, the width direction region of the portion of the liquid column P located above the liquid contact portion of the wafer W may be located inward of the peripheral edge of the wafer W. This prevents the organic solvent discharged from the solvent supply nozzle 46 from spreading from the peripheral edge of the wafer W toward the lower rear surface of the wafer W due to the tendency of the organic solvent to flow in the discharge direction.

In the wafer processing according to the present embodiment, the solvent supply nozzle 46 is provided so as to be inclined such that the organic solvent discharged from the solvent supply nozzle 46 is directed toward the downstream side in the rotation direction of the wafer W rotated by the rotation holding unit 20. Therefore, the generation of droplets of the organic solvent caused by the collision of the organic solvent discharged from the solvent supply nozzle 46 with the rotating wafer W can be suppressed.

In the present embodiment, the peripheral edge removal of the wafer surface using the same solvent supply nozzle 46 is performed after the resist film drying step in which the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W is performed until the resist film drying step is completed. When the peripheral edge of the front surface of the wafer is turned to be removed, the solvent continues to be discharged from the solvent supply nozzle 46 without interruption. Therefore, the generation of the flocs due to the resist can be suppressed continuously even during the period from the completion of the peripheral edge removal including the transition to the peripheral edge removal.

The wafer processing according to the present embodiment can be performed using an apparatus having a conventional configuration including a solvent supply nozzle for removing the peripheral edge of the front surface of the wafer.

Further, the resist coating apparatus 1 used for wafer processing according to the present embodiment is simple in structure and therefore easy to maintain.

< confirmation test 1>

The present inventors conducted a test to confirm the effect of suppressing the generation of the flocs by the wafer treatment of the present invention.

In the confirmation test 1, the exhaust pressure from the exhaust pipe 37 of the cup 30 (hereinafter referred to as "cup exhaust pressure") was measured using the resist coating apparatus 1 having the structure shown in fig. 2 and 3.

In the example, the wafer processing explained using fig. 4 and 5 was performed.

In comparative example 1, wafer processing different from the wafer processing described with reference to fig. 4 and 5 in the following points was performed. That is, the difference in the wafer processing is that the organic solvent is not continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W in step S2 and step S3.

In comparative example 2, the same wafer treatment as in comparative example 1 was performed, and an organic solvent as a cleaning liquid was supplied from the cleaning liquid supply nozzle 50 to the back surface of the wafer W while rotating the wafer W in advance, so that the collecting member 60 was wetted with the organic solvent.

Fig. 7 is a graph showing the results of the confirmation test 1. In fig. 7, the horizontal axis represents the elapsed time from the start of the resist solution supply step of step S2 described above, and the vertical axis represents the cup exhaust pressure.

As shown in fig. 7, in comparative example 1, the cup-shaped body exhaust pressure was about 120Pa at maximum in the drying step of step S4. In contrast, in the example, the cup discharge pressure was about 75Pa at the time when the cup discharge pressure became maximum in comparative example 1 in the drying step of step S4. That is, in the example, the increase in the exhaust pressure of the cup-shaped bodies can be suppressed by about 40% as compared with comparative example 1.

In comparative example 2, the cup-shaped body exhaust pressure was set to about 100Pa at the maximum in the drying step of step S4. In contrast, in the example, the cup discharge pressure was about 75Pa at the time when the cup discharge pressure became maximum in comparative example 2 in the drying step of step S4. That is, in the example, the increase in the exhaust pressure of the cup-shaped bodies can be suppressed by about 25% as compared with comparative example 2.

< confirmation test 2>

The present inventors also obtained the film thickness distribution after wafer processing in the above example and the film thickness distribution after wafer processing in the above comparative example 1.

According to the confirmation test 2, the film thickness distribution after wafer processing in the example was not changed from the film thickness distribution after wafer processing in the comparative example 1. That is, in step S2 and step S3, the effect of the organic solvent being continuously supplied from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W on the film thickness distribution of the resist film is not confirmed.

In addition, as shown in comparative example 2, when the organic solvent is supplied to the back surface of the wafer W in advance, not only does the time required for the entire wafer processing become long, but also the portion of the back surface of the wafer W that is in contact with the organic solvent is cooled. Accordingly, it is found that the film thickness distribution of the wafer W is affected by the large contact area of the back surface of the wafer W with the organic solvent. Such a tendency was not observed in the film thickness distribution after the wafer processing of the example.

< confirmation test 3>

In the confirmation test 3, the resist coating apparatus 1 having the structure shown in fig. 2 and 3 was used to successively perform the wafer processing described with reference to fig. 4 and 5 on 5 wafers W, and the cup evacuation pressure at this time was measured.

Fig. 8 is a graph showing the result of confirmation test 3. In fig. 8, the horizontal axis represents the elapsed time from the start of the resist solution supply step of step S2 described above, and the vertical axis represents the cup exhaust pressure. In fig. 8, the results of comparative example 1 are also shown without comparison.

As shown in fig. 8, in the case where the continuous process is performed on 5 wafers W, the history of the cup exhaust pressure during the process hardly changes. That is, even when a plurality of wafers W are continuously processed in the wafer processing according to the present embodiment, the increase in the exhaust pressure of the cup can be stably suppressed.

< modification of the present embodiment >

In the above example, the continuous supply of the organic solvent from the solvent supply nozzle 46 to the peripheral edge portion of the front surface of the wafer W is started after the supply of the resist solution is stopped, but the continuous supply may be started before the supply of the resist solution is stopped. The continuous supply may be started before the supply of the resist solution is started. However, by starting the continuous supply after stopping the supply of the resist solution, the consumption amount of the organic solvent can be suppressed.

In the above example, the continuous supply of the organic solvent is also performed in the step of drying the resist film, but the continuous supply of the organic solvent may be omitted in the step of drying the resist film. By continuously supplying the organic solvent also in the step of drying the resist film, the generation of the flocs can be further suppressed. On the other hand, in the step of drying the resist film, the consumption amount of the organic solvent can be suppressed by omitting the continuous supply of the organic solvent.

The embodiments disclosed herein are merely illustrative in all aspects and should not be considered as restrictive. The above-described embodiments may be omitted, replaced, or modified in various ways without departing from the scope of the claims and the gist thereof.

Claims

1. A method of treating a liquid, comprising:

a step of supplying a coating liquid to the front surface of the substrate; and

a step of forming a coating film on the front surface of the substrate by rotating the substrate and diffusing the supplied coating liquid on the front surface,

in the step of forming the coating film, the solvent of the coating liquid is continuously supplied from the solvent supply portion to the peripheral portion from before the coating liquid reaches the peripheral portion of the front surface of the substrate, and the step of forming the coating film is continued at least until the end of the step of forming the coating film.

2. The liquid treatment method according to claim 1, characterized by comprising:

the solvent is continuously supplied from the solvent supply portion to the peripheral portion so that a liquid column of the solvent discharged from the solvent supply portion comes into contact with the edge inclined portion of the peripheral portion.

3. The liquid treatment method according to claim 1 or 2, characterized by:

the step of forming a coating film includes a step of drying the coating film by rotating the substrate,

in the drying step, the solvent is continuously supplied from the solvent supply portion to the peripheral portion.

4. The liquid treatment method according to claim 3, characterized by comprising:

the method comprises the following steps: and a step of removing the coating liquid in a predetermined region on the peripheral side of the front surface of the substrate by using the solvent from the solvent supply unit after the drying step.

5. The liquid treatment method according to claim 4, characterized in that:

when the solvent is continuously supplied from the solvent supply portion to the peripheral portion, the solvent is supplied from the solvent supply portion to the region from which the coating liquid is removed in the removing step.

6. The liquid treatment method according to claim 4 or 5, characterized in that:

the step of removing is performed after the solvent is continuously supplied from the solvent supply portion to the peripheral portion, and the solvent continues to be released from the solvent supply portion without interruption.

7. A liquid treatment apparatus, comprising:

a rotation holding part for holding the substrate and rotating the substrate;

a coating liquid supply unit configured to supply a coating liquid to the front surface of the substrate held by the spin holding unit;

a solvent supply unit configured to supply a solvent of the coating liquid to the front surface of the substrate held by the spin holding unit; and

a control part for controlling the operation of the display device,

the control section executes the steps of:

supplying the coating liquid from the coating liquid supply part to the front surface of the substrate; and

in the step of forming a coating film, a control signal is outputted so that the solvent is continuously supplied from the solvent supply portion to the peripheral portion from before the coating liquid reaches the peripheral portion of the front surface of the substrate, and so that the step of forming a coating film is continued at least until the step of forming a coating film is finished.