JP7546461B2 - Liquid processing method and liquid processing device - Google Patents

Description

This disclosure relates to a liquid processing method and a liquid processing device.

In the substrate processing apparatus of Patent Document 1, a disk-shaped cup base is disposed below the rotating holder, and an annular inner cup is attached to the cup base. A through hole is formed in the center of the cup base, and the rotating shaft of a motor is disposed passing through the through hole, with the rotating holder attached to its tip. A number of air holes are formed in the cup base along the through hole. The air holes are disposed at a position corresponding to the inside of the outer periphery of the rotating holder. When the substrate held in the rotating holder rotates at high speed, air is supplied to the back side of the substrate through the air holes, preventing the space on the back side of the substrate from becoming negative pressure, thereby preventing mist from getting around to the back side of the substrate.

Japanese Patent Application Publication No. 11-283899

The technology disclosed herein prevents the formation of cotton-like clumps caused by coating liquid being shaken off the substrate.

One aspect of the present disclosure includes a step of supplying a coating liquid to a surface of a substrate, and a step of diffusing the coating liquid on the surface to form a coating film on the surface, wherein, in the step of forming the coating film, before the coating liquid reaches a peripheral portion of the surface of the substrate, continuous supply of the coating liquid from a solvent supply section to the peripheral portion in a state in which a liquid column of the solvent is formed is started, and continues at least until the step of forming the coating film is completed.

This disclosure makes it possible to prevent the occurrence of cotton-like clumps of coating liquid that are shaken off from the substrate.

FIG. 2 is a diagram showing a schematic view of a thread-like portion formed by a coating liquid shaken off from a substrate. 1 is a longitudinal sectional view showing an outline of a configuration of a resist coating apparatus as a liquid processing apparatus according to an embodiment of the present invention. 1 is a cross-sectional view showing an outline of the configuration of a resist coating apparatus as a liquid processing apparatus according to an embodiment of the present invention. 10 is a flowchart for explaining an example of a flow of wafer processing in a resist coating apparatus. 3A to 3C are diagrams each showing a schematic state of a wafer W during each process included in the wafer processing. 1A and 1B are diagrams illustrating an example of the position of a solvent supply nozzle during continuous supply of an organic solvent. FIG. 1 shows the results of confirmation test 1. FIG. 13 shows the results of confirmation test 3.

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

The coating process described above widely uses the so-called spin coating method, in which a coating liquid is supplied to the surface of a rotating wafer, and centrifugal force is used to spread the coating liquid over the surface of the wafer, coating the entire surface of the wafer with the coating liquid. Liquid processing equipment that applies coating using the spin coating method is provided with a container called a cup to prevent the coating liquid that has been scattered from the surface of the rotating wafer from scattering around. In addition, exhaust is performed from the bottom of the cup in order to form a desired airflow on the surface of the coating film, etc.

In recent years, it is sometimes required to form a coating film with a large thickness on the surface of a wafer. For example, a coating liquid with a high viscosity is used to form a coating film with a large thickness. When a spin coating method is used with a coating liquid with a high viscosity, a part of the coating liquid supplied to the surface of the wafer is shaken off from the peripheral surface of the wafer, and at that time, as shown in FIG. 1, it is stretched in a thread-like shape from the peripheral surface of the wafer W toward the outside in the radial direction to form a thread-like portion H. The thread-like portion H is further stretched by further rotation of the wafer W, and dries and solidifies. The solidified thread-like portion H becomes entangled with each other and becomes a cotton-like mass. For example, the cotton-like mass is separated from the wafer W during the process, and causes problems such as blocking the exhaust path in the cup of the liquid processing device and obstructing exhaust. If exhaust from inside the cup of the liquid processing device is obstructed and the exhaust pressure rises, for example, a desired air flow cannot be formed on the surface of the coating film on the wafer, and a film thickness distribution with a uniform film thickness cannot be obtained.

Therefore, the technology disclosed herein prevents the formation of cotton-like clumps caused by coating liquid being shaken off the wafer.

The liquid processing method and liquid processing device according to this embodiment will be described below with reference to the drawings. Note that in this specification and drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and duplicated explanations will be omitted.

(Liquid Treatment Apparatus)
2 and 3 are a longitudinal sectional view and a transverse sectional view showing the outline of the configuration of a resist coating apparatus 1 as a liquid processing apparatus according to this embodiment.

The resist coating apparatus 1 has a processing vessel 10 whose interior can be sealed as shown in FIG. 2. A loading/unloading port (not shown) for a wafer W as a substrate is formed on the side of the processing vessel 10.

A rotating holder 20 is provided in the processing vessel 10 to hold and rotate the wafer W. Specifically, the rotating holder 20 holds the wafer W and rotates the wafer W around a rotation axis perpendicular to the surface of the wafer W. The rotating holder 20 also has a spin chuck 21 configured to be rotatable while holding the wafer W, and a chuck driver 22 having an actuator such as a motor to rotate the spin chuck 21. The spin chuck 21 is configured to be freely rotatable at various speeds (number of rotations) by the chuck driver 22. The chuck driver 22 is also provided with a lifting drive mechanism having an actuator such as a cylinder, and the spin chuck 21 is configured to be freely lifted and lowered by the lifting drive mechanism.

A cup 30 is also provided within the processing vessel 10. The cup 30 includes an outer cup 31 arranged 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 periphery of the outer cup 31. The outer cup 31 receives and collects liquid that splashes or falls from the wafer W.

As shown in FIG. 3, a rail 40 is formed on the negative X-direction (downward in FIG. 3) side of the outer cup 31, extending along the Y-direction (left-right direction in FIG. 3). The rail 40 is formed, for example, from the outside of the negative Y-direction (leftward in FIG. 3) side of the outer cup 31 to the outside of the positive Y-direction (rightward in FIG. 3) side. The rail 40 is provided with two arms 41, 42.

The first arm 41 supports a resist liquid supply nozzle 43 as a coating liquid supply unit. The resist liquid supply nozzle 43 supplies resist liquid as a coating liquid to the surface of the wafer W held by the spin chuck 21. The resist liquid discharged and supplied by the resist liquid supply nozzle 43 has a high viscosity of 100 cp or more. The first arm 41 is freely movable on the rail 40 by a nozzle drive unit 44 having an actuator such as a motor, which is a moving mechanism for the resist liquid supply nozzle 43. This allows the resist liquid supply nozzle 43 to move from a waiting unit 45 installed outside the outer cup 31 on the negative Y-direction side to above the center of the wafer W in the outer cup 31. In addition, the first arm 41 can be freely raised and lowered by the nozzle drive 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 resist liquid supply source is provided with a supply device group (not shown) for controlling the supply of resist liquid from the resist liquid supply source to the resist liquid supply nozzle 43. The supply device group includes, for example, a supply valve that switches between supplying and stopping the supply of resist liquid and a flow rate adjustment valve that adjusts the flow rate of the resist liquid.

The second arm 42 supports a solvent supply nozzle 46 as a solvent supply unit. The solvent supply nozzle 46 supplies the coating liquid solvent to the surface of the wafer W held by the spin chuck 21. The solvent supplied by the solvent supply nozzle 46 is, for example, an organic solvent such as thinner. The second arm 42 is movable on the rail 40 by a nozzle drive unit 47 having an actuator such as a motor, which is a movement mechanism for the solvent supply nozzle 46. This allows the solvent supply nozzle 46 to move from a waiting unit 48 provided on the outside of the outer cup 31 on the positive Y-direction side to above the peripheral portion of the wafer W in the outer cup 31. In addition, the nozzle drive unit 47 allows the second arm 42 to be raised and lowered freely, and the height of the solvent supply nozzle 46 can be adjusted.

The solvent supply nozzle 46 is connected to a supply source of organic solvent (not shown). A supply pipe (not shown) connecting the solvent supply nozzle 46 to the organic solvent supply source is provided with a group of supply devices (not shown) for controlling the supply of organic solvent from the organic solvent supply source to the solvent supply nozzle 46. The group of supply devices includes, for example, a supply valve that switches between supplying and stopping the supply of organic solvent and a flow rate adjustment valve that adjusts the flow rate of the organic solvent.

The solvent supply nozzle 46 is tilted so that the organic solvent discharged from the solvent supply nozzle 46 is directed toward the downstream side of the rotation direction of the wafer W by the rotating holder 20. In other words, the solvent supply nozzle 46 is tilted so that the discharge direction D of the organic solvent from the solvent supply nozzle 46 (see the thick arrow in FIG. 3) is directed toward the downstream side of the rotation direction of the wafer W by the rotating holder 20 in a plan view.

2, a cleaning liquid supply nozzle 50 is provided 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 by the cleaning liquid supply nozzle 50 is, for example, an organic solvent such as thinner, and may be the same as the solvent supplied by 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 cleaning liquid supply source is provided with a group of supply devices (not shown) for controlling the supply of cleaning liquid from the cleaning liquid supply source to the cleaning liquid supply nozzle 50. The group of supply devices includes, for example, a supply valve that switches between supplying and stopping the cleaning liquid and a flow rate adjustment valve that adjusts the flow rate of the cleaning liquid.

A cylindrical wall 31a is provided at the bottom of the outer cup 31, and a cylindrical wall 32a is provided at the bottom of the inner cup 32. A gap is formed between these walls 31a and 32a, forming an exhaust path d. In addition, below the inner cup 32, a curved path is formed by a horizontal member 33a that is circular in plan view, a cylindrical outer peripheral vertical member 33b and an inner peripheral vertical member 33c, and a bottom member 33d that is circular in plan view and located at the bottom. This curved path constitutes a gas-liquid separation section.

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

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

In addition, a collection member 60 is provided in the cup 30 so as to block the upper part of the exhaust path d provided between the wall 31a of the outer cup 31 and the wall 32a of the inner cup 32. The collection member 60 is a member that collects resist liquid that has been stretched into a thread-like shape and solidified, and is made of a metal such as SUS. In addition, the collection member 60 blocks the exhaust path d as described above, but has an opening 61 that communicates in the vertical direction, so that exhaust is possible through the opening 61. The collection member 60 is, for example, a member that is annular in plan view, and the openings 61 are provided so as to be aligned at equal intervals along the circumferential direction. In addition, the collection member 60 is provided in the cup 30 so that, for example, its upper surface is approximately horizontal.

As shown in FIG. 2, the resist coating apparatus 1 is provided with a control unit 100. The control unit 100 is, for example, a computer equipped with a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores programs that realize various processes in the resist coating apparatus 1. For example, the program storage unit stores a program that outputs control signals to the aforementioned supply equipment groups provided for the chuck drive unit 22, the nozzle drive units 44 and 47, the resist liquid supply nozzle 43, the solvent supply nozzle 46, and the cleaning liquid supply nozzle 50, respectively, to realize the wafer processing described below. The above program may be recorded in a non-transitory storage medium readable by a computer and installed in the control unit 100 from the storage medium. A part or all of the program may be realized 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 Figures 4 to 6. Figure 4 is a flow chart for explaining an example of the flow of wafer processing in the resist coating apparatus 1. Figure 5 is a diagram showing a schematic view of the state of the wafer W during each step of the wafer processing. Figure 6 is a diagram showing an example of the position of the solvent supply nozzle 46 during continuous supply of an organic solvent, 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 loaded into the processing vessel 10, placed on the spin chuck 21 of the rotating holder 20, and held by suction (step S1).

Next, a resist liquid is supplied onto the surface of the wafer W from the resist liquid supply nozzle 43 (step S2).
Specifically, the wafer W held by the spin chuck 21 is rotated at a rotation speed ω1 (e.g., 50 to 150 rpm), and the resist liquid is supplied from the resist liquid supply nozzle 43 to the center of the surface Ws of the wafer W, as shown in Fig. 5A. As a result, a puddle of the resist liquid is formed in the central region of the surface Ws of the wafer W.

Next, the wafer W is rotated, and the resist liquid is spread over the surface of the wafer W by the centrifugal force caused by the rotation, forming a resist film on the surface, and organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W (step S3).

Specifically, in step S2, after a puddle of resist liquid is formed and the supply of resist liquid from the resist liquid supply nozzle 43 is stopped, the wafer W is rotated at a rotation speed ω2 (e.g., 400 to 1000 rpm) higher than the rotation speed ω1. The centrifugal force at this time causes the coating liquid on the surface Ws of the wafer W to spread toward the periphery, as shown in FIG. 5(B).

Before the spread resist liquid reaches the peripheral portion We of the surface Ws of the wafer W, the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion We. Specifically, for example, immediately after the supply of the resist liquid from the resist liquid supply nozzle 43 is stopped, the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion We. This allows the organic solvent to be present at the peripheral portion We at the time when the spread resist liquid reaches the peripheral portion We and at any subsequent time. In other words, the peripheral portion We can be wetted with the organic solvent. Therefore, the resist liquid that reaches the peripheral portion We of the surface Ws of the wafer W mixes with the organic solvent and its viscosity decreases. If the viscosity of the resist liquid on the peripheral portion We of the surface Ws of the wafer W is reduced as described above, the aforementioned thread-like portion H (see FIG. 1) is unlikely to form when it is shaken off from the surface peripheral portion. Therefore, in the diffusion process of step S3 and subsequent processes, the generation of cotton-like lumps due to the resist liquid shaken off from the wafer W can be suppressed.

The "periphery" refers to the portion of the surface of the wafer W that is located outside the semiconductor device formation area and is within a non-device formation area, for example, a portion that is within 1 mm of the edge of the surface of the wafer W.

When organic solvent is continuously supplied to the peripheral portion We of the surface Ws of the wafer W, the position of the solvent supply nozzle 46 is, for example, a position where the liquid column P formed by the organic solvent ejected from the solvent supply nozzle 46 contacts the bevel B of the peripheral portion of the surface of the wafer W, as shown in FIG. 6.

After the resist film is formed, the wafer W is further rotated, and the resist film is dried while the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W (step S4).
Specifically, after the resist liquid is spread over the entire surface (excluding the periphery) of the wafer W in step S2, that is, after the resist film is formed covering the entire surface (excluding the periphery) of the wafer W, the wafer W is rotated at a rotation speed ω3 (e.g., 1000 to 1500 rpm) higher than the rotation speed ω2. By rotating the wafer W at this rotation speed ω3 for a predetermined time, the resist film on the surface of the wafer W can be dried.

During this drying, the resist liquid forming the resist film may reach the peripheral portion of the surface of the wafer W and be shaken off from the peripheral portion of the surface of the wafer W to form the aforementioned thread-like portion H (see FIG. 1). In contrast, in this example, even in this drying process, as shown in FIG. 5(C), the organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion We of the surface Ws of the wafer W. Specifically, the continuous supply of the organic solvent is continued until the end of this drying process. Therefore, when the resist liquid forming the resist film reaches the peripheral portion of the surface of the wafer W, it mixes with the organic solvent and its viscosity decreases. If the viscosity of the resist liquid forming the resist film on the peripheral portion of the surface of the wafer W is reduced as described above, it is less likely to form the aforementioned thread-like portion (see FIG. 1) when it is shaken off from the peripheral portion of the surface. Therefore, in this drying process, the generation of cotton-like lumps due to the resist liquid shaken off from the wafer W can be suppressed.

After the drying process, the coating liquid in a predetermined area on the peripheral side of the surface of the wafer W is removed by the organic solvent from the solvent supply nozzle 46 (step S5).
Specifically, following the continuous supply of organic solvent from the solvent supply nozzle 46 in the drying process of step S4, removal of the coating liquid from a predetermined region on the peripheral side of the surface of the wafer W (hereinafter, sometimes referred to as "peripheral removal of the wafer surface") is performed, and during the transition to peripheral removal of the wafer surface, the discharge of the solvent from the solvent supply nozzle 46 is continued without interruption. Also, during peripheral removal of the wafer surface, the wafer W is rotated at a rotation speed ω4 that is approximately the same as the rotation speed ω2.
The position at which the liquid column P lands on the wafer W during the continuous supply of the organic solvent to the peripheral surface of the wafer W, which is started in step S3, is set within the peripheral removal region of the wafer surface.
Furthermore, the continuous supply in steps S3 and S4 may be performed without changing the flow rate of the organic solvent when removing the peripheral edge of the wafer surface in step S5, for example.

Furthermore, in step S5, the coating liquid that has reached the rear surface of the wafer W is also removed.
Specifically, the cleaning liquid is discharged from the cleaning liquid supply nozzle 50 toward the rear surface of the wafer W rotating at the rotation speed ω4 as described above. As a result, the cleaning liquid is supplied to a portion of the rear surface of the wafer W that is on the outer periphery side of the portion where the cleaning liquid discharged from the cleaning liquid supply nozzle 50 was discharged, and the coating liquid that has flowed around from the periphery of the front surface of the wafer W to the rear surface is also removed. In addition, the cleaning liquid supplied to the rear surface of the wafer W is shaken off from the periphery of the rear surface of the wafer W and supplied to the collection member 60. Therefore, if a cotton-like mass or the like is collected by the collection member 60, the cotton-like mass or the like can be dissolved and removed.
The position at which the cleaning liquid is ejected from the cleaning liquid supply nozzle 50 onto the back surface of the wafer W is inside the position at which the organic solvent is ejected from the solvent supply nozzle 46 onto the front surface of the wafer W, and is, for example, a position 80 mm to 120 mm radially inward from the periphery of the wafer W.

Thereafter, the wafer W is removed from the spin chuck 21 and unloaded from the processing chamber 10 (step S6).
This completes a series of wafer processing steps in the resist coating apparatus 1.

As described above, the wafer processing according to this embodiment includes a process of supplying resist liquid to the surface of the wafer W, and a process of rotating the wafer W to diffuse the supplied resist liquid on the surface of the wafer W and form a resist film on the surface (hereinafter, sometimes referred to as a "diffusion and formation process"). In the above-mentioned wafer processing, before the resist liquid reaches the peripheral portion of the surface of the wafer W in the diffusion and formation process, continuous supply of organic solvent from the solvent supply nozzle 46 to the peripheral portion is started and continues at least until the diffusion and formation process is completed. Therefore, in the diffusion and formation process and subsequent processes, the resist liquid on the peripheral portion We of the surface Ws of the wafer W is mixed with the organic solvent supplied from the solvent supply nozzle 46 and has a low viscosity, so that when it is shaken off from the peripheral portion of the surface, it is difficult to form the above-mentioned thread-like portion H (see FIG. 1). Therefore, according to the wafer processing according to this embodiment, it is possible to suppress the generation of cotton-like lumps due to the resist liquid shaken off from the wafer W in the diffusion and formation process and subsequent processes. As a result, it is also possible to suppress the occurrence of defects caused by cotton-like lumps.

Furthermore, in the wafer processing of this embodiment, in the processes essential for forming a resist film (e.g., the diffusion and formation processes), only the continuous supply of organic solvent from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W is performed in parallel, so that the time required for the entire processing is not lengthened and throughput is not reduced.
It is also possible to continuously supply the organic solvent during the diffusion/forming process, etc., not from the solvent supply nozzle 46 but from the cleaning liquid supply nozzle 50 that supplies the organic solvent as a cleaning liquid to the back surface of the wafer W. In this case, however, even if the organic solvent from the cleaning liquid supply nozzle 50 can be made to flow around the peripheral portion of the front surface of the wafer W, the area of the portion of the wafer W that comes into contact with the organic solvent and is cooled is too large, which significantly affects the film thickness distribution. Therefore, in this embodiment, the organic solvent is continuously supplied during the diffusion/forming process, etc., from the solvent supply nozzle 46 located above the wafer W, i.e., located on the front surface side of the wafer W.

Furthermore, in the wafer processing according to this embodiment, even in the resist film drying process that follows the diffusion and formation process, the continuous supply of organic solvent from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W continues. This makes it possible to further prevent the generation of cotton-like lumps caused by the resist liquid shaken off from the wafer W in the drying process. In addition, by continuing the continuous demand for the organic solvent until the end of the resist film drying process, the generation of cotton-like lumps can be further prevented.

In addition, in this embodiment, when organic solvent is continuously supplied to the peripheral portion of the surface of the wafer W, the position of the solvent supply nozzle 46 is, for example, a position where the liquid column P formed by the organic solvent discharged from the solvent supply nozzle 46 contacts the bevel B of the peripheral portion of the surface of the wafer W. As a result, the portion of the organic solvent supplied to the peripheral portion of the surface of the wafer W on the bevel B side, i.e., the portion on the outer periphery side, moves toward the outer periphery along the bevel. On the other hand, the portion of the organic solvent supplied to the peripheral portion of the surface of the wafer W on the inner periphery side is pulled to the portion on the bevel B side by the surface tension of the organic solvent itself, and also moves toward the outer periphery due to the centrifugal force caused by the rotation of the wafer W. Therefore, the organic solvent from the solvent supply nozzle 46 can be prevented from moving toward the inner periphery from the supply position on the surface of the wafer W.

Furthermore, in the wafer processing according to this embodiment, the solvent supply nozzle 46 is tilted so that the organic solvent discharged from the solvent supply nozzle 46 is directed toward the downstream side of the direction of rotation of the wafer W by the rotating holder 20. This prevents the organic solvent discharged from the solvent supply nozzle 46 from colliding with the rotating wafer W and causing splashes of the organic solvent.

In addition, in this embodiment, following the resist film drying process in which an organic solvent is continuously supplied from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W, which is carried out until the end of the resist film drying process, the same solvent supply nozzle 46 is used to remove the peripheral portion of the wafer surface. Then, when moving to the peripheral removal of the wafer surface, the discharge of the solvent from the solvent supply nozzle 46 is not interrupted but continues. Therefore, the generation of cotton-like bodies derived from the resist can be continuously suppressed even during the period until the completion of the peripheral removal, including the transition to the peripheral removal.

Furthermore, the wafer processing according to this embodiment can be performed using an apparatus of an existing configuration having a solvent supply nozzle for removing the peripheral edge of the wafer surface.
Furthermore, the resist coating apparatus 1 used in the wafer processing according to this embodiment has a simple configuration, and therefore is easy to maintain.

<Confirmation test 1>
The present inventors conducted a test to confirm the effectiveness of wafer processing according to the present disclosure in suppressing the generation of floccules.
In this confirmation test 1, the resist coating apparatus 1 having the configuration shown in FIGS. 2 and 3 was used, and the exhaust pressure from the exhaust pipe 37 of the cup 30 (hereinafter referred to as the "cup exhaust pressure") was measured.

In the example, the wafer processing described with reference to FIGS. 4 and 5 was carried out.
4 and 5 was performed in the following respect: In other words, in steps S2 and S3, the organic solvent was not continuously supplied from the solvent supply nozzle 46 to the peripheral portion of the front surface of the wafer W.
In Comparative Example 2, the same wafer processing as in Comparative Example 1 was performed, and in addition, an organic solvent was supplied as a cleaning liquid from a cleaning liquid supply nozzle 50 to the back surface of the wafer W while rotating the wafer W, thereby wetting the collection member 60 with the organic solvent.

Figure 7 shows the results of confirmation test 1. In Figure 7, the horizontal axis shows the elapsed time from the start of the resist liquid supply process in step S2 described above, and the vertical axis shows the cup exhaust pressure.

7, in Comparative Example 1, the cup exhaust pressure reached a maximum of approximately 120 Pa in the drying process of step S4. In contrast, in the Example, the cup exhaust pressure reached a maximum in Comparative Example 1 in the drying process of step S4, and was approximately 75 Pa. In other words, in the Example, the increase in cup exhaust pressure can be suppressed by approximately 40% compared to Comparative Example 1.
In Comparative Example 2, the cup exhaust pressure reached a maximum of approximately 100 Pa in the drying process of step S4. In contrast, in the Example, the cup exhaust pressure reached a maximum in Comparative Example 2 in the drying process of step S4, and was approximately 75 Pa. In other words, in the Example, the increase in cup exhaust pressure can be suppressed by approximately 25% compared to Comparative Example 2.

<Confirmation test 2>
The inventors also obtained the film thickness distribution after wafer processing in the above-mentioned Example and the film thickness distribution after wafer processing in the above-mentioned Comparative Example 1.
According to this confirmation test 2, the film thickness distribution after wafer processing in the example was not different from the film thickness distribution after wafer processing in the above-mentioned comparative example 1. In other words, no effect on the film thickness distribution of the resist film due to the continuous supply of organic solvent from the solvent supply nozzle 46 to the peripheral portion of the front surface of the wafer W in steps S2 and S3 was confirmed.
When an organic solvent is supplied to the rear surface of the wafer W in advance as in Comparative Example 2, not only does the time required for the entire wafer processing increase, but also the portion of the rear surface of the wafer W that is in contact with the organic solvent is cooled. Since the portion of the rear surface of the wafer W that is in contact with the organic solvent is large, it is known that this affects the film thickness distribution of the wafer W. No such tendency was observed in the film thickness distribution after the wafer processing in the example.

<Confirmation test 3>
In this confirmation test 3, the resist coating apparatus 1 having the configuration shown in Figures 2 and 3 was used, and the wafer processing described using Figures 4 and 5 was performed continuously on five wafers W, and the cup exhaust pressure at that time was measured.

Fig. 8 is a diagram showing the results of confirmation test 3. In Fig. 8, the horizontal axis indicates the elapsed time from the start of the resist solution supply process in step S2 described above, and the vertical axis indicates the cup exhaust pressure. In addition, Fig. 8 also shows the results of the above-mentioned comparative example 1 for comparison.
8, when five wafers W were continuously processed, the history of the cup exhaust pressure hardly changed between processes. In other words, according to the wafer processing of this embodiment, even when a plurality of wafers W were continuously processed, the increase in the cup exhaust pressure can be stably suppressed.

<Modifications of this embodiment>
In the above example, the continuous supply of the organic solvent from the solvent supply nozzle 46 to the peripheral portion of the surface of the wafer W is started after the supply of the resist liquid is stopped, but the continuous supply may be started before the supply of the resist liquid is stopped. Also, the continuous supply may be started before the supply of the resist liquid is started. However, by starting the continuous supply after the supply of the resist liquid is stopped, the consumption of the organic solvent can be reduced.

In the above examples, the organic solvent was continuously supplied in the resist film drying process, but the continuous supply of the organic solvent may be omitted in the resist film drying process. By continuously supplying the organic solvent in the resist film drying process, the generation of cotton-like lumps can be further suppressed. On the other hand, by omitting the continuous supply of the organic solvent in the resist film drying process, the consumption of the organic solvent can be reduced.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

1 Resist coating device 20 Rotation holding part 43 Resist liquid supply nozzle 46 Solvent supply nozzle 100 Control part B Bevel W Wafer We Periphery part Ws Surface

Claims (7)

supplying a coating liquid to a surface of a substrate;
and rotating the substrate to spread the supplied coating liquid on the surface of the substrate to form a coating film on the surface.
A liquid processing method, comprising: before the coating liquid reaches a peripheral portion of a surface of the substrate in a step of forming the coating film, continuous supply of the coating liquid from a solvent supply section to the peripheral portion in a state in which a liquid column of the solvent is formed is started; and the supply is continued at least until the step of forming the coating film is completed. The liquid processing method according to claim 1 , wherein the solvent is continuously supplied from the solvent supply part to the peripheral edge portion such that a liquid column of the solvent contacts a bevel of the peripheral edge portion. Following the step of forming the coating film, a step of rotating the substrate to dry the coating film is included;
The liquid processing method according to claim 1 , wherein the continuous supply of the solvent from the solvent supply part to the peripheral portion in a state in which a liquid column of the solvent is formed is continued even in the drying step. The liquid processing method according to claim 3, further comprising a step of removing the coating liquid from a predetermined area on the peripheral side of the surface of the substrate using the solvent from the solvent supply unit after the drying step. 5. The liquid processing method according to claim 4, wherein, when the solvent is continuously supplied from the solvent supply part to the peripheral portion while forming a liquid column of the solvent, the solvent is supplied from the solvent supply part into the region from which the coating liquid is removed in the removing step. 6. The liquid processing method according to claim 4 or 5, wherein the removing step is carried out following continuous supply of the solvent from the solvent supply part to the peripheral portion while forming a liquid column of the solvent, and discharge of the solvent from the solvent supply part is continued without interruption. a rotation holder that holds and rotates the substrate;
a coating liquid supply unit that supplies a coating liquid to a surface of the substrate held by the spin holder;
a solvent supply unit that supplies a solvent for the coating liquid to a surface of the substrate held by the spin holder;
A control unit,
The control unit is
supplying a coating liquid from the coating liquid supply unit to a surface of a substrate;
a step of rotating the substrate to spread the supplied coating liquid on the surface of the substrate and form a coating film on the surface;
a liquid processing apparatus that outputs a control signal so that continuous supply of the solvent from the solvent supply unit to the peripheral portion in a state in which a liquid column of the solvent is formed is started before the coating liquid reaches the peripheral portion of the surface of the substrate in the process of forming the coating film, and continues at least until the process of forming the coating film is completed.

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