JP3160832B2 - Method and apparatus for forming coating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a coating film for forming a liquid coating film using a solvent such as a resist film on a coating body such as an LCD substrate or a layer formed thereon. A method and an apparatus therefor.

[0002]

2. Description of the Related Art As is well known, in the field of semiconductor technology,
When selectively etching a semiconductor layer, an insulator layer, and an electrode layer formed on an LCD substrate into a predetermined pattern,
As in the case of a semiconductor wafer, a resist film is formed on the surface of a layer as masking of a pattern portion.

For example, as a method of forming a resist film, a rectangular LCD substrate (hereinafter, referred to as a substrate) is placed and fixed on a mounting table provided in the processing container, and an opening of the processing container is covered. Close the body, rotate the processing container and the mounting table, for example, a resist solution composed of a solvent and a photosensitive resin is dropped into the center of the upper surface of the substrate, and the resist solution is rotated with the rotational force and centrifugal force of the substrate. There is known a method in which a substrate is spirally diffused from the center of the substrate toward the peripheral edge and applied.

In this method, the solvent in the resist solution evaporates in the process of diffusing the resist solution from the center position of the substrate toward the periphery. For this reason, the viscosity of the resist solution differs in the diffusion direction, and the thickness of the formed resist film differs between the central portion and the peripheral portion. Further, since the peripheral speed of the substrate is much higher at the outer peripheral portion than at the center position, the amount of the substrate scattered is large. That is, there was a limit to uniform coating.

[0005] For this reason, for example, a method of controlling the temperature of the resist solution or filling the same solvent used in the resist solution in the atmosphere for forming the resist film to suppress the evaporation of the solvent in the resist solution, A method is conceivable in which the solvent of the resist solution is dropped on the substrate surface before coating.

[0006]

However, evaporation of the solvent in the resist solution is suppressed by filling the same solvent used for the resist solution in the former, ie, adjusting the temperature of the resist solution or in the atmosphere for forming the resist film. In the method, the amount of the resist solution used is large, and for example, only several% of the applied amount of the resist solution contributes to the actual formation of the resist film. In addition, since the amount of the resist liquid is large, the resist liquid wraps around the back surface of the corner portion of the substrate, and the resist liquid attached to the back surface of the corner portion of the substrate dries, causing a problem of generating particles. Furthermore, when a resist solution is applied without adding a solvent, air is taken into the resist solution during the application and bubbles are contained, resulting in a problem that the film thickness becomes uneven. In addition, even in the latter method, in which the solvent of the resist solution is dropped on the substrate surface before the application of the resist solution, the uniformity of the solvent itself on the substrate and the difference in the dry state make it difficult to apply uniformly, and the above problem is sufficiently solved. It cannot be solved.

The present invention has been made in view of the above circumstances, and requires only a small amount of a coating solution such as a resist solution, and is capable of forming a coating film having a uniform thickness. It is intended to provide a device.

[0008]

According to a first aspect of the present invention, there is provided a method of forming a coating film, comprising: supplying a coating liquid onto one surface of a substrate housed in a processing container to form a coating film. In the method, a step of applying a solvent on one surface of the substrate, and in a region where the solvent is applied on the substrate, while the solvent is not dried, supplying a predetermined amount of coating liquid,
Rotating at a first number of revolutions to diffuse over the entire surface of the substrate; closing the lid in the processing container and enclosing the substrate in the processing container; and closing the lid. The processing container and the substrate are moved to the second rotation speed higher than the first rotation speed .
And a step of adjusting the film thickness of the coating film by rotating at a rotation speed of (Claim 1).

In the method of forming a coating film according to the present invention, it is preferable to rotate the substrate and the processing container together (claim 2).

In the method of forming a coating film according to the present invention, the amount of the coating liquid is set according to the first rotation speed of the substrate.

Further, the amount of the coating liquid and the number of rotations of the substrate are
The thickness of the coating film is set so that the variation in film thickness is about ± 2% or less of the average film thickness.

Further, the application of the solvent can be performed by rotating the substrate. In this case, the rotation speed of the solvent application performed by the rotation of the substrate is set to a rotation speed different from the first rotation speed and the second rotation speed.

Further, it is preferable to apply a solvent of a coating solution as the solvent (claim 7).

Further, the supply of the coating liquid onto the substrate may be performed at any position, but it is preferable to supply the coating liquid almost at the center of the substrate.

Further, according to the present invention, there is provided an apparatus for forming a coating film, comprising: substrate supporting means for supporting one surface of a substrate facing upward; and spreading the coating liquid over the entire surface of the substrate.
To adjust the first rotation speed and the thickness of the coating film
A substrate rotating means for rotating at a second rotation speed higher than the first rotation speed, a cup-shaped processing container surrounding the substrate, a lid for closing an opening of the processing container, A solvent supply means for supplying a solvent for the coating liquid, a coating liquid supply means for supplying the coating liquid to the substrate, a solvent supply means for supporting the solvent supply means and the coating liquid supply means, and a supported solvent supply means and coating liquid supply And a means for movably supporting the means between a supply position above the substrate and a standby position deviating from the supply position.
9 ).

Further, another coating film forming apparatus of the present invention comprises:
A substrate supporting means for supporting one side of the substrate facing upward, and the substrate supporting means , applying the coating liquid over the entire surface of the substrate.
Adjust the first rotation speed and the thickness of the coating film to diffuse
Substrate rotating means for rotating at a second rotation speed higher than the first rotation speed, a cup-shaped processing container surrounding the substrate, a lid for closing an opening of the processing container, and the substrate A solvent supply means for supplying a solvent of the coating liquid to the substrate, a coating liquid supply means for supplying the coating liquid to the substrate, the solvent supply means and the coating liquid which support the solvent supply means and the coating liquid supply means. A coating mechanism including means for movably supporting a supply unit between a supply position above the substrate and a standby position deviating from the supply position; and an edge of the substrate on which a coating film is formed by the coating mechanism. it is characterized in that it comprises a coating film removing mechanism for removing a coating film adhered to the part (claim 10). In this case, the substrate is carried into the coating mechanism, it is provided a transport mechanism for unloading from the coating film removing mechanism is preferably (claim 16).

[0017] In the coating film forming apparatus of the present invention, it is provided a container rotating means for rotating the processing chamber with the substrate is preferably (claim 11). Further, it is preferable that the application liquid supply means and the application liquid supply source for storing the application liquid are communicated via a supply pipe, and the supply pipe is provided with a pump means capable of adjusting the supply amount of the application liquid. Claim 12 ). In this case, as the pump means, for example, a bellows pump,
A pump having a stepping motor that expands and contracts the bellows pump so that the coating liquid is supplied by the bellows pump can be used, and a diaphragm pump can also be used. Of course, it is also possible to discharge by pressure feeding without using a pump.

Further, at least one coating liquid supply means and said solvent supply means, who provide a temperature adjusting means is preferably (claim 13).

[0019] The apparatus may further comprise a lid moving means for movably supporting the lid for closing the opening of the processing container between a closed position of the processing container and a standby position separated from the processing container. (Claim 14 ).

Further, the cover, substrate solvent and the coating solution provided with an opening to supply the in process container, the opening may be closable formed in the lid (claim 15).

[0021]

According to the present invention, the solvent of the coating solution is applied on one surface of the substrate and diffused, and then the solvent is applied to a region substantially at the center of the substrate where the solvent is applied. There in a state of wet, supplying a predetermined amount of the coating liquid, the coating
The substrate is rotated at the first rotation speed to diffuse the cloth liquid, the coating liquid is diffused over the entire surface of the substrate, and the lid is closed in the processing container, and the substrate is sealed in the processing container. After that, the processing container and the substrate with the lid closed are moved to the first container .
By rotating at a second rotation speed higher than the rotation speed of, the thickness of the coating film is adjusted. This makes it possible to supply a coating liquid having a proper mixing ratio to the solvent, to reduce the amount of the coating liquid used, and to prevent the coating liquid from flowing into the back surface of the corner of the substrate. Further, the viscosity of the coating solution caused by contact between the solvent and the coating solution can be made uniform to form a coating film having a uniform thickness.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Here, a case will be described in which the coating film forming method and the coating film forming apparatus of the present invention are applied to a method and an apparatus for forming a resist film on an LCD (liquid crystal display) substrate (glass substrate).

As shown in FIG. 1, the above-mentioned coating film forming apparatus has a rectangular substrate as an object to be coated, for example, an LCD substrate G
A rotating body, for example, a spin chuck 10 (substrate supporting means) for holding the substrate G in a horizontal state by vacuum so as to support one surface thereof (hereinafter referred to as a substrate) upward, and an upper portion and an outer peripheral portion of the spin chuck 10 A cup-shaped processing container 12 (hereinafter referred to as a “rotating cup”) having an opening at an upper portion having a processing chamber 11 to be surrounded, and an opening 12 of the rotating cup 12
a cover 16 which is attached (detachable) so as to be able to be closed on a, a robot arm 20 which is a cover moving means for moving the cover 16 to a closed position and a standby position, and an outer peripheral side of the rotary cup 12. Ring-shaped drain cup 1 arranged as follows
4, a drive motor 21 for rotating the spin chuck 10 and the rotating cup 12, and the spin chuck 10
The supply nozzle 40 (solvent supply means) for the solvent (solvent) A of the coating liquid and the supply nozzle 50 (coating liquid supply means) for the coating liquid, for example, the resist liquid B, which are configured to be movable to a position above, are integrated in close proximity. Spout 60 attached to the
A scanning mechanism 70 is provided as a moving means for holding the nozzle 0 and moving it between the jetting stand-by position and the substrate upper position. In each of the solvent supply path and the resist liquid supply path from the nozzles 40 and 50, a temperature adjustment liquid C for setting the solvent A and the resist liquid B flowing therein to a preset temperature (for example, 23 ° C.) is circulated. A supply temperature adjusting mechanism 61 is provided.

The spin chuck 10 is driven based on a preset program, and can be rotated (rotated) in the horizontal direction via a rotating shaft 22 that is rotated by driving a drive motor 21 that can change the rotation speed. Also, it can be moved up and down by driving a lifting cylinder 23 connected to the rotating shaft 22. In this case, the rotating shaft 22 is provided with a bearing 25 on the inner peripheral surface of the fixed collar 24.
a and is slidably connected to a spline bearing 27 fitted on the inner peripheral surface of the rotatable inner cylinder 26a rotatably mounted via the inner cylinder 26a. A driven pulley 28a is mounted on the spline bearing 27, and the driven motor 21 is mounted on the driven pulley 28a.
A belt 29a is stretched between a drive shaft 21a and a drive pulley 21b mounted on the drive shaft 21a. Therefore, the drive shaft 21 is driven by the drive motor 21 via the belt 29a.
2 rotates, and the spin chuck 10 rotates. Also,
The lower side of the rotating shaft 22 is disposed in a cylindrical body (not shown).
The rotation shaft 22 can be moved in the vertical direction by driving the lift cylinder 23 through the lift cylinder 23.

The rotating cup 12 is fixed to the fixed collar 2.
4 is mounted via a connecting cylinder 31 fixed to the upper end of a rotary outer cylinder 26b mounted via a bearing 25b on the outer peripheral surface of the rotary cup 12, between the bottom 12b of the rotary cup 12 and the lower surface of the spin chuck 10. A bearing 32 having a sealing function is interposed therebetween so as to be rotatable relative to the spin chuck 10. The drive from the drive motor 21 is transmitted to the rotary cup 12 by a driven pulley 28b mounted on the rotary outer cylinder 26b and a belt 29b stretched over a drive pulley 21b mounted on the drive motor 21 so that the rotary cup 12 is driven. Rotated. In this case, the diameter of the driven pulley 28b is formed to be the same as the diameter of the driven pulley 28a mounted on the rotary shaft 22, and the belts 29a and 29b are stretched over the same drive motor 21.
The rotating cup 12 and the spin chuck 10 rotate the same.
The fixed collar 24, the rotating inner cylinder 26a and the rotating outer cylinder 2
A labyrinth seal portion 33 is formed on the surface facing the surface 6b to prevent dust from entering the rotary cup 12 from the lower drive system during the rotation process (see FIG. 3).

The rotating cup 12 has a tapered surface 12e whose side wall 12c is reduced in diameter toward the upper side.
An inward flange 12d is formed inward from the upper end of the side wall 12c. Air supply holes 34 are formed in the upper peripheral portion of the rotating cup 12, that is, the inward flange 12 d, at appropriate intervals in the circumferential direction, and the lower peripheral portion, that is, the lower portion of the side wall 12 c, is exhausted at an appropriate position in the circumferential direction. A hole 35 is drilled. By providing the air supply hole 34 and the exhaust hole 35 in this manner, when the rotating cup 12 rotates, the air flowing into the processing chamber 11 from the air supply hole 34 flows to the outside from the exhaust hole 35, so that the rotation of the rotary cup 12 Sometimes it is possible to prevent the processing chamber 11 from becoming negative pressure,
The cover 16 can be easily opened without requiring a large force when opening the cover 16 from the rotating cup 12 after the processing.

On the other hand, an annular passage 14a is provided inside the drain cup 14, and exhaust gas connected to an exhaust device (not shown) is provided at an appropriate position (for example, four positions in the circumferential direction) on the outer peripheral wall of the annular passage 14a. A port 36 is provided, and a radial exhaust passage 37 communicating with the exhaust port 36 is formed in an upper portion on the inner peripheral side of the drain cup 14 (see FIG. 1). As described above, the exhaust port 3 is provided on the outer peripheral portion of the drain cup 14.
6 and an exhaust passage 37 communicating with the exhaust port 36 is formed in the upper part on the inner peripheral side of the drain cup 14, so that it is scattered by centrifugal force in the processing chamber 11 during the rotation process and drains through the exhaust hole 34. The mist that has flowed into the cup 14 is prevented from rising to the upper side of the rotating cup 12 and can be discharged to the outside from the exhaust port 36.

The annular passage 14a is provided with the drain cup 14
The outer wall 14b rising from the bottom of the drain cup 14 and the inner wall 14c hanging down from the ceiling of the drain cup 14 are detoured so that the exhaust can be performed uniformly.
A drain hole 14e is provided in the bottom 14d located between the inner wall 14b and the inner wall 14c at appropriate intervals in the circumferential direction.

On the inner peripheral surface of the drain cup 14, a tapered surface 14f whose diameter is reduced toward the upper side so as to be close to the tapered surface 12e of the rotary cup 12 is formed. A minute gap is formed between the drain cup 14 and the tapered surface 14f. By forming the tapered minute gap that expands downward as described above, the rotation cup 1 is rotated when the rotation cup 12 rotates.
A pressure difference is induced from the peripheral speed difference between the upper and lower portions of the minute gap between the drain cup 14 and the drain cup 14, and this pressure difference causes the airflow from the upper side to the lower side of the minute gap on the outer peripheral portion of the rotary cup 12. By promoting this, it is possible to prevent the exhaust mist in the drain cup 14 from scattering to the outside of the rotary cup 12 through the minute gap.

Further, even if there is a mist which is directed upward through the minute gap and is scattered to the outside of the rotary cup 12, the mist is sucked by the exhaust passage 37, is directed into the drain cup 14, and is discharged from the exhaust port 36.

In the above embodiment, the case where the drain cup 14 is disposed so as to surround the outer peripheral side of the rotary cup 12 has been described. However, the drain cup 14 does not necessarily need to be disposed on the outer peripheral side of the rotary cup 12. , Rotating cup 1
2 may be arranged on the lower side.

During the rotation process, the lid 16 needs to be fixed to the opening 12a of the rotating cup 12 and rotated integrally. Therefore, as shown in FIG. 4, a fixing pin 17a protruding from the upper part of the rotating cup 12 and this fixing pin 17a
The fitting recess 17b is fitted into the cover 1
6 is fixed to the rotating cup 12. In this case, by forming the top of the fixing pin 17a in a spherical shape, dust generated by contact with the fitting recess 17b is reduced. Note that the fixing pin 17a does not necessarily need to protrude toward the rotating cup, and the fixing pin 17a may protrude from the lid, and a fitting recess 17b may be provided on the rotating cup. Further, the inside of the fitting recess 17b may be connected to suction means (not shown) to discharge dust generated by the contact between the fixing pin 17a and the fitting recess 17b to the outside.

When the lid 16 is opened and closed, the robot arm 20 is inserted under the bulging head 18 protruding from the upper surface of the lid 16 as shown by an imaginary line in FIG. After engaging a locking pin 20a protruding from the robot arm 20 with a locking groove 18a provided in the portion 18, the robot arm 20 can be moved up and down. The locking groove 18a of the bulging head 18 when the lid 16 is opened and the locking pin 20a of the robot arm 20 are aligned, and the fixing pin 17a when the lid 16 is closed.
The position of the fitting recess 17b can be adjusted by controlling the rotation angle of the drive motor 21 formed by a servomotor or the like.

In the above embodiment, the lid 16 and the rotating cup 1
2 has been described by fitting the fixing pin 17a and the fitting recess 17b. However, such a structure is not necessarily required, and the lid 16 is separately provided using a pressing mechanism.
Is fixed to the rotating cup 12, it is possible to prevent the generation of dust when the lid 16 is opened and the rattling of the lid 16 during the rotation processing.

A baffle plate (not shown) formed of a perforated plate or the like having a size equal to or larger than the substrate G attached to the lid 16 at the center portion is provided at an intermediate position between the lid 16 and the substrate G. ) Can also be arranged. By arranging the baffle plate in this manner, the processing chamber 11 can be more reliably formed during the coating process.
The occurrence of turbulence in the inside can be prevented.

On the other hand, the solvent supply nozzle 40 is connected to a solvent tank 43 via a solvent supply tube 41 serving as a solvent supply path and an opening / closing valve 42, and is used to supply nitrogen (N 2) gas supplied into the solvent tank 43. By controlling the pressurization, the solvent A in the solvent tank 43 can supply a predetermined amount of the solvent A onto the substrate G for a predetermined time.

The resist solution supply nozzle 50 is connected to a resist solution tank 52 (coating solution supply source) for storing a resist solution B via a resist solution supply tube 51 which is a resist solution supply passage. The tube 51 has a suck back valve 53, an air operation valve 54,
A bubble removing mechanism 55 for separating and removing bubbles in the resist solution B, a filter 56, and a bellows pump 57 are sequentially provided. The bellows pump 57 is capable of expanding and contracting under the control of the driving unit, and a predetermined amount of resist solution B is supplied to the substrate G
For example, it can be supplied to the central part of the liquid crystal. It is possible to control the supply amount of the resist solution B smaller than the supply amount of the conventional resist solution B. The driving unit is constituted by a ball screw 58 having a screw at one end adsorbed to one end of the bellows pump, a nut screwed to the screw, and a stepping motor 59 for linearly moving the screw by rotating the nut. It is configured. The diameter of the resist liquid supply nozzle 50 is specifically set to φ0.5 to φ5 mm, preferably φ3 mm for a substrate of 500 × 600 mm. Thus, by setting the diameter of the nozzle according to the size of the substrate, it is possible to supply a small amount of the resist solution B as much as possible over a long time. If the supply time is short, the uniformity of the film thickness is not good, and if it is too long, the resist solution does not reach the peripheral portion of the substrate. Here, as small as possible depends on the nozzle diameter and the resist solution supply pressure.

In the resist liquid supply system configured as described above, the discharge time of the resist liquid is controlled by the bellows pump 57.
(Control accuracy: ± 2 msec) by the driving time of the stepping motor 59. Further, the discharge amount of the resist liquid is set by a driving operation of the bellows pump 57, for example, a driving time and a driving speed, and an opening / closing operation (ON-OFF operation) of the air operation valve 54 for opening and closing the resist liquid supply passage. It has become. Setting of the driving time of the bellows pump 57 and ON / OFF of the air operation valve 54
The operation is automatically controlled by the operation of a computer based on a preset program.

The discharge time of the resist solution B is controlled by a variable orifice (not shown) provided in the resist solution supply nozzle 50.
It can also be performed by opening and closing operations. Also, the N solution to the resist solution tank 52 can be used without using the bellows pump 57.
It is also possible to supply the resist solution B by pressurizing the two gases. In this case, the discharge time of the resist solution B can be controlled by adjusting the pressurized amount of the N2 gas.

The suck back valve 53 provided in the resist liquid supply system discharges the resist liquid B remaining on the inner wall of the tip of the resist liquid supply nozzle 50 due to surface tension after the resist liquid is discharged from the resist liquid supply nozzle 50. This is a valve for drawing back into the resist liquid supply nozzle 50, thereby preventing solidification of the remaining resist liquid. In this case, when the resist liquid supply nozzle 50 that discharges a small amount of the resist liquid B draws the resist liquid B back into the resist liquid supply nozzle 50 by the negative pressure action of the suck back valve 53 as usual, the air near the tip of the nozzle 50 also becomes The residue of the resist solution B adhering to the tip of the nozzle 50 enters the nozzle 50 and clogs the nozzle 50, and the dried resist becomes particles and the substrate G is contaminated. At the same time, there is a risk that the yield will be reduced.

In order to solve this problem, as shown in FIG.
The thickness 50b of the portion near the opening is larger than that of FIG. That is, the nozzle 50 has a cylindrical tip and an inverted truncated cone following the cylindrical tip. Instead, as shown in FIG. 5B, an outer flange 5 is provided at the cylindrical tip or opening of the resist solution supply nozzle 50.
0c, the nozzle 5 during suckback
0 Entrapment of air near the front end can be prevented.
Further, as shown in FIG. 5C, a small-diameter bent portion 50d extending in a horizontal S-shape is formed at a vertically extending cylindrical tip of the resist liquid supply nozzle 50, and the center of the bent portion 50d is formed. By performing suckback to the vicinity, air entrapment at the nozzle tip can be similarly prevented.

The temperature adjusting mechanism 61 (temperature adjusting means)
As shown in FIG. 6, a temperature adjustment liquid supply path 62 is provided to surround the outer circumferences of the solvent supply tube 41 and the resist supply tube 51, respectively. , A circulation pump 64 provided in each of the circulation paths 63, and a temperature adjustment liquid C connected in the middle of the circulation path 63.
(For example, constant temperature water) at a constant temperature. With the temperature adjusting mechanism 61 configured as described above, the solvent A flowing in the solvent supply tube 41 and the resist liquid B flowing in the resist supply tube 51 can be maintained at a predetermined temperature (for example, about 23 ° C.).

In FIG. 6, the solvent supply nozzle 40 and the solvent supply tube 41 are connected to the resist solution supply nozzle 50.
The resist solution supply tube 51 and the resist solution supply tube 51 are formed integrally with each other. However, as will be described in detail below with reference to FIG.

The jet head 60 is formed of, for example, a member made of stainless steel or an aluminum alloy. A U-shaped hole forming a part of the bypass passage 60b is formed on the upper surface of the jet head 60, and a vertical through hole 60c extending to the lower surface of the jet head 60 is formed at the bottom of the hole. Each through-hole 60c has an inclined middle portion 60d having a larger diameter as it goes downward, and a large-diameter lower portion 60e.
A female screw is formed on the inner peripheral surface of 0e. When the nozzles 40, 50 are mounted on the jet head 60 having such a configuration, the cylindrical nozzles 40, 50 are inserted into the through holes 60c so that the upper and lower portions extend, respectively. A sealing member 66 made of a substantially conical synthetic resin having a vertical through hole through which 50 can penetrate is packed in the inclined middle portion 60d, and a mounting screw member 67 having a vertical through hole through which the nozzles 40 and 50 can penetrate is screwed to the lower part. By screwing the seal member 66 into the inside 5c, the seal member 66 is pressed against the inclined inner peripheral surface of the inclined middle portion 60d. Thus, the nozzle 40,
50 is mounted on the jet head 60 in a liquid-tight manner. In this case, the O-ring 68 is interposed between the upper surface of the inclined middle portion 60d and the upper surface of the seal member 66 as shown in the drawing, so that the watertightness between the bypass passage 15 and the nozzles 40 and 50 is further ensured. be able to.

A holding pin 6 is provided on the upper surface on one side of the jet head 60.
0a is projected, and a scan arm 71 holding the holding pin 60a is moved by the scan mechanism 70 in the X, Y directions.
By moving in the (horizontal) and Z (vertical) directions, the jet head 60, that is, the solvent supply nozzle 40 and the resist solution supply nozzle 50 are moved between the operation position above the center of the substrate G and the standby position above the nozzle standby unit 72. To be moved selectively.

In this case, four types of jet heads 60 are provided according to the type of the resist solution (see FIG. 2). That is, the nozzle standby section 72 is provided with four jet heads 60, and the resist liquid supply nozzles 5 of these jet heads 60 are provided.
Numerals 0 communicate with tanks containing different resist solutions having different viscosities and the like. In this case, only the resist supply nozzle 50 is provided for each jet head 60, and the solvent supply nozzle 40 is attached to the tip of the scan arm 71 in advance so that it can be commonly used for all the jet heads 60. You may. In this case, a plurality of solvent supply nozzles 40, for example, a straight pipe may be provided, and the solvent may be supplied from a plurality of locations at once along the radial direction of the substrate. In this case, nozzles having different discharge diameters may be provided, and the discharge from each nozzle may be arbitrarily controlled according to the magnitude of the discharge flow rate or a change in the discharge flow rate.

The standby section 46 of the rinse liquid supply nozzle 45 is provided on the side facing the nozzle standby section 72 (see FIG. 2). Further, by disposing the cleaning nozzle 47 in the connecting cylinder 31 fixed without rotating on the lower side of the rotating cup 12, the inner surfaces of the rotating cup 12 and the lid 16 can be cleaned. That is, the cleaning nozzle 47 is held by a bracket 48 attached to the rotating shaft 22, and a cleaning liquid supply pipe 49 connected to the cleaning nozzle 47 is externally shown through a passage (not shown) provided in the fixed collar 24. 3, the spin chuck 10 is lifted up and the cleaning nozzle 47 is exposed from between the spin chuck 10 and the bottom of the rotating cup 12 to rotate the cleaning liquid as shown by the imaginary line in FIG. Rotating cup 12
And, it can be sprayed on the inner surface of the lid 16.

Next, a procedure of forming a resist film by the coating film forming apparatus having the above-described configuration will be described with reference to a flowchart of FIG.

First, the lid 16 of the rotating cup 12 is opened, and the substrate G is moved onto the stationary spin chuck 10 by a transfer arm (not shown), and the substrate G is held by the spin chuck 10 by vacuum suction. Support G. Next, the substrate G is rotated at a lower speed than the steady rotation during processing by the rotation drive of the spin chuck 10 (rotation speed: for example, 100 to 600 rpm, acceleration: 300 to 500 rpm).
m / sec), and the rotating cup 12 is rotated at the same speed. During this rotation, for example, ethyl cellosolve acetate (ECA) is applied to the substrate surface from the solvent supply nozzle 40 of the spout 60, which is gripped by the scan arm 71 by the scan mechanism 70 and moved above the center of the substrate G, as a solvent A of the coating liquid. ) Is supplied, for example, 26.7 cc, for example, for 20 seconds (sec), for example, is dropped (step).
Alternatively, the solvent A may be dropped while the substrate G is stationary without rotating, and then the substrate G may be rotated. After the solvent A is supplied for 20 seconds in this way, the supply of the solvent A is stopped while the rotation speed of the spin chuck 10 and the rotating cup 12 is at the low rotation speed (step).

Next, the spin chuck 10 is rotated at a high speed (first rotation speed: 600 to 1000 rpm, for example, 1000 rpm, acceleration: 300 to 600 rpm).
/ Sec), at the same time, in the central portion of the solvent film on the substrate surface, that is, in the region where the solvent a is dropped (applied), the coating solution is supplied from the resist solution supply nozzle 50a while the solvent A is not dried. For example, the resist solution B is
During supply, for example, 10 cc is dropped (step). The drying time of the solvent A at this time can be obtained in advance by an experiment. For example, when the surface of the substrate G is visually observed and the interference fringes of light are visible, the drying is not performed, and when the interference fringes are dried, the interference fringes become invisible, so that the time can be known. Therefore, it is possible to know when to supply the resist solution B in a state where the solvent A is not dried. In this case 5s
The drive time of the bellows pump 57 can be controlled during the supply time between ec, and the supply amount of the resist solution can be accurately and finely controlled. After supplying (dropping) the resist solution B for 5 seconds in this way, the supply of the resist solution B is stopped, and at the same time, the spin chuck 10 is stopped.
Then, the rotation of the rotating cup 12 is stopped (step).

After stopping the supply of the resist solution and moving the resist solution supply nozzle 50 to the standby position, the robot arm 2
0, the lid 16 is moved to the upper opening 12 of the rotating cup 12.
a, and the substrate G is sealed in the rotating cup 12 (step).

Thus, the opening 1 of the rotating cup 12 is
The spin chuck 10 and the rotating cup 12 are rotated, for example, for 15 sec (second rotation speed: for example, 1350 rpm, acceleration: 50) in a state in which the lid 2a is closed and sealed by the lid 16.
0 rpm / sec) to adjust the thickness of the resist film (step). After the coating process is completed, the rotation of the spin chuck 10 and the rotation cup 12 is stopped, the lid 16 is moved to the standby position by the robot arm 20, and the substrate G is taken out by the transfer arm (not shown).
The application operation is completed.

The coating film forming apparatus according to the present invention configured as described above can be used alone as a resist coating apparatus for the LCD substrate G, and can also be used by being incorporated into a resist coating and developing processing system for the LCD substrate G described later. can do. Hereinafter, the structure of a resist coating and developing system incorporating the coating film forming apparatus of the above embodiment will be described.

The above resist coating / developing system comprises:
As shown in FIG. 9, a loader unit 9 for loading / unloading a substrate G is provided.
0, a first processing unit 91 of the substrate G, and a second processing unit 92 connected to the first processing unit 91 via the relay unit 93. The second processing unit 92 includes a delivery unit 94
An exposure device 95 for exposing a predetermined fine pattern to a resist film via the resist film can be connected in series.

The loader unit 90 includes a cassette 96 for storing an unprocessed substrate G, a cassette mounting table 98 for mounting a cassette 97 for storing a processed substrate G, and a cassette 96 on the cassette mounting table 98. , 97 and the substrate G
Tweezers 9 that can be moved and rotated (θ) in the horizontal (X, Y) direction and the vertical (Z) direction in order to carry in / out a substrate.
9.

The first processing unit 91 is provided with a transfer mechanism such as a main arm 80 capable of moving in the X, Y, and Z directions and rotating θ.
A brush cleaning device 120 for cleaning the substrate G with a brush, a jet water cleaning device 130 for cleaning the substrate G with high-pressure jet water, and an adhesion processing device for hydrophobizing the surface of the substrate G. 105 and substrate G
And a cooling processing device 106 for cooling to a predetermined temperature,
On the other side of the transport path 102, a coating processing device 107 (coating mechanism) and a coating film removing device 108 (coating film removing mechanism), which are the coating film forming devices of the present invention, are arranged.

On the other hand, like the first processing section 91, the second processing section 92 has a main arm 80a that can move in the X, Y, and Z directions and can rotate θ, and the transport path 102a of the main arm 80a. A heat treatment device 109 for heating the substrate G before and after the application of the resist solution to perform pre-baking or post-baking is disposed on one side of the substrate, and a developing device 110 is disposed on the other side of the transport path 102a.

The relay section 93 has a structure in which casters 93d are provided on the bottom surface of a box 93c having a delivery table 93b on which support pins 93a for supporting the substrate G are erected. The relay unit 93 is pulled out from the first processing unit 91 and the second processing unit 92, and the first processing unit 91
Alternatively, a worker can enter the second processing unit 92 to easily perform repairs and inspections.

The transfer section 94 includes a cassette 111 for temporarily holding the substrate G, and a cassette 1
Tweezers 1 for transferring a substrate G to and from the substrate 11
12 and a delivery table 113 for the substrate G are provided.

In the coating / development processing system configured as described above, the unprocessed substrate G accommodated in the cassette 96 is taken out by the loading / unloading tweezers 99 of the loader unit 90, and then the first processing unit 91 The brush is transferred to the main arm 80 and then transferred into the brush cleaning device 120. The substrate G that has been brush-cleaned in the brush cleaning device 120 is subsequently cleaned with high-pressure jet water in the jet water cleaning device 130. Thereafter, the substrate G is subjected to a hydrophobizing treatment by the adhesion processing device 105 and cooled by the cooling treatment device 106,
Is carried into the coating mechanism, that is, the coating processing apparatus 107,
In the coating processing apparatus 107, a photoresist, that is, a photosensitive film is coated and formed by the above-described procedure, and subsequently, an unnecessary resist film on the side of the substrate G is removed by the coating film removing apparatus 108. Substrate G from which unnecessary resist film is removed
Is transported out of the coating film removing device 108 by the main arm 80 and transported to the next step. Therefore, when the substrate G is carried out thereafter, the resist film on the edge portion is removed, so that the resist does not adhere to the main arm 80. Then, this photoresist is applied to the heat treatment device 109.
After heating and baking, a predetermined pattern is exposed by the exposure device 95. Then, the exposed substrate G is transported into the developing device 110, and after being developed with the developing solution, the developing solution is washed away with the rinsing solution to complete the developing process.

The processed substrate G that has been subjected to the development processing is accommodated in the cassette 97 of the loader unit 90, and then carried out and transported to the next processing step.

In the above embodiment, the structure in which the solvent supply nozzle 40 is provided integrally with the resist liquid supply nozzle 50 at the jet head 60 has been described. However, the present invention is not limited to this, and the embodiment shown in FIG. As shown in the example, the solvent may be supplied integrally with the jet head 46 having the rinse liquid supply nozzle 45.

In this example, a common temperature control mechanism 61 is provided for the solvent supply path and the resist liquid supply path (see FIG. 11). The jet head 60 and the scan arm 71 of the scanning mechanism 70 are integrally formed, and a temperature adjusting liquid supply path 62 is formed between the jet head 60 and the scan arm 71. In the supply path 62, the solvent supply tube 41 and the resist liquid supply tube 51 are provided. And the temperature of the solvent A and the resist solution B can be controlled by the same temperature control liquid C. With this configuration, the temperature control mechanism 61
Can be simplified, and the solvent A and the resist solution B can be maintained at the same temperature.

The arrangement and configuration of the jet head 60 and the nozzles 40 and 50 are not limited to the above example.
2 to 15 may be used. The example shown in FIG. 12 is a case where the solvent supply nozzle 40 is arranged on the outer periphery of the resist liquid supply nozzle 50 coaxially therewith. For this purpose, the resist solution supply nozzle 50 and the solvent supply nozzle 40 have a double tube structure, and the tip of the solvent supply nozzle 40 projects below the tip of the resist solution supply nozzle 50. Of course, the tip of the solvent supply nozzle 40 may be configured so that the tip of the solvent supply nozzle 50 is at the same level as the tip of the resist solution supply nozzle 50, or the former is shorter. Instead, a resist liquid supply nozzle 50 may be provided outside the solvent supply nozzle 40. Further, as shown in FIG. 13, the resist solution supply nozzle 50 and the solvent supply nozzle 4
0 may be provided in parallel, and a mechanism in which these discharge ports 69 are common may be adopted.

As shown in FIG. 14, an annular solvent storage tank 60 formed in a jet head 60 and having a discharge port 69 at the center.
f, the tip of the solvent supply nozzle 40 is inserted into the solvent in the tank 60f.
The upper end of the nozzle 50 may be exposed to the atmosphere of a vaporized solvent. In this manner, the solvent supply nozzle 40
The tip of the resist solution supply nozzle 5
The resist adhering to 0 can be washed with a solvent, and the resist solution can be prevented from drying.
Generation of particles due to drying of the resist solution can be prevented.

As shown in FIG. 15, the solvent supply nozzle 40 extends in parallel along the outer periphery of the resist solution supply nozzle 50.
May be arranged, and the tip of the nozzle 40 may be branched in a plurality, in this example, four. As a result, the solvent is supplied to four places at a time. Preferably, these branch nozzle portions 40a are respectively disposed so as to correspond to four corners of a rectangle similar to the substrate G, and the solvent is simultaneously supplied to a symmetric position on a diagonal line with respect to the center of the substrate G. You. This makes it possible to make the diffusion of the solvent uniform to some extent on the rectangular substrate.

Next, an example of the method of forming a resist film according to the present invention will be described based on experiments. * Experiment 1 For example, ECA was used as the solvent A, and after supplying this solvent A under a predetermined amount (for example, 25 cc) under the above-mentioned step conditions, that is, at a rotation speed of 500 rpm and a time of 20 sec, a resist solution supply nozzle was used. An experiment was performed under the following conditions when supplying (dropping) the resist solution B onto the substrate G from 50.

Conditions Discharge (supply) time of resist liquid: 2 sec, 5 sec Rotation speed: 300, 500, 600, 800, 1000 r
pm Dimensions of the substrate G: 500 × 600 mm As a result of the above Experiment 1, the number of rotations was 600 rpm (strictly speaking,
Discharge speed less than 500-800 rpm), time: 5 s
In ec, when 8 cc / sheet of the resist solution B is supplied, the amount of resist necessary to coat the entire surface of the substrate G can be minimized (see FIG. 16), and the film thickness profile is as shown in FIG. And the variation (range) of the thickness of the coating film becomes 597 angstroms (Å).
It was found that a uniform film thickness of about 600 angstroms (Å) of about ± 2% of the average film thickness could be formed. In addition, changing the rotation speed to 800 rpm and 1000 rpm, 5
When the resist solution B is supplied for seconds, the variation (range) of the thickness of the coating film can be reduced to 412,240 Å (Å), but the resist amount may be slightly increased to 10 cc / sheet. found.

* Experiment 2 Ethyl cellosolve acetate (ECA) was used as the solvent A, and after supplying this solvent A under the following conditions, the resist liquid B was supplied (dropped) from the resist liquid supply nozzle 50 onto the substrate G. An experiment was conducted in the case where the above was performed.

Conditions Resist: TSMR-8900 Viscosity: 15 cp Rotation speed: 300, 500, 800, 1000 rpm Solvent flow rate: 80, 100, 120, 150 cc / min Dimension of substrate G: 500 × 600 mm The experiment was conducted under the above conditions. And the results shown in Table 1 were obtained.

[0071]

[Table 1]

As a result of the above experiment 2, as shown in FIG.
It can be seen that the higher the number of revolutions and the higher the flow rate of the solvent per unit time, the shorter the discharge (supply) time is. Also, from a different point of view, the flow rate x time = actual usage value ,
As shown in FIG. 19, it was found that the higher the number of rotations, the smaller the amount of solvent used.

When the film thickness profile of the coating film was measured based on Experiment 2, the results shown in Table 2 were obtained.

[0074]

[Table 2]

As a result of the above experiment 2, the number of rotations was 800 rpm
m, solvent flow rate: 150 cc / min, solvent discharge time: 9
sec, the amount of solvent: 22.5 cc, the variation in film thickness (range) is 364 angstroms (Å), the number of revolutions: 1000 rpm, and the flow rate of solvent: 150 cc / mi.
n, the solvent discharge time: 8 sec, and the solvent amount: 20 cc, the variation (range) of the film thickness was 582 angstrom (Å), and the film thickness could be made uniform.

Examples of the coating solution include a resist (phenol novolak resin and naphthoquinonediazide ester),
ARC (Anti-reflection film; Anti Reflection)
Coating) may be used. Examples of the solvent include methyl-3-methoxypropionate (MMT, boiling point: 145 ° C, viscosity: 1.1 cps), ethyl lactate (EL, boiling point: 154 ° C, viscosity: 2.6 cps), ethyl-3 -Ethoxypropionate (EEP, boiling point: 17)
0 ° C., viscosity: 1.3 cps), ethyl pyruvate (E
P, boiling point: 144 ° C., viscosity: 1.2 cps), propylene glycol monomethyl ether acetate (PGME
A, boiling point: 146 ° C., viscosity: 1.3 cps), 2-heptanone (boiling point: 152 ° C., viscosity: 1.1 cps), cyclohexanone (solvent for ARC), and others known in this field can be used.

In the above embodiment, the lid 16 of the rotary cup 12 is moved and opened by the robot arm 20 to supply the solvent A supply nozzle 40 and the resist solution B supply nozzle 50.
In the above description, a configuration in which the solvent A and the resist liquid B are dropped by moving the scanning mechanism 70 above the central portion of the substrate G, but the dropping is performed in a state where the opening 12a of the rotary cup 12 is closed by the lid 16 is described. May be configured.

For example, as shown in FIG. 20, the bulging head 18 of the lid 16 is formed in a hollow shape to provide an opening 18a, and the upper end of the opening 18a can be closed by the lid 18A. . Then, the cover 18A is opened, the nozzle is moved above the hollow of the bulging head 18, that is, above the center of the substrate G by the scanning mechanism 70, and the solvent A and the resist liquid B are dropped through the opening 18a. You may.

In the above embodiment, the case where the coating film forming apparatus according to the present invention is applied to a resist coating apparatus for an LCD substrate has been described, but a coating film forming apparatus for an object to be processed such as a semiconductor wafer or a CD other than the LCD substrate. Of course, the present invention can also be applied to a polyimide-based coating liquid (PIQ) other than a resist, a coating liquid containing a glass agent (SOG), and the like.

[0080]

As described above, according to the present invention, after a solvent is applied to one surface of a substrate, the solvent is applied to a region on the substrate where the solvent is applied, in a state where the solvent is not dried. in, supplying a predetermined amount of the coating solution, the <br/> substrate in order to diffuse the coating liquid is rotated at a first rotational speed to diffuse the coating solution over the entire one surface of the substrate, the lid to the processing chamber After closing the body and enclosing the substrate in the processing container, the processing container and the substrate with the lid closed are rotated at a second rotation speed higher than the first rotation speed to obtain a coating film thickness. Therefore, it is possible to supply a coating liquid having a proper mixing ratio to the solvent, to reduce the amount of the coating liquid used, and to prevent the coating liquid from flowing into the back surface of the corner of the substrate. Further, the viscosity of the coating solution caused by contact between the solvent and the coating solution can be made uniform to form a coating film having a uniform thickness.

[Brief description of the drawings]

FIG. 1 is a schematic view of a coating film forming apparatus for performing a coating film forming method according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of the coating film forming apparatus shown in FIG.

FIG. 3 is an enlarged sectional view of a main part of the coating film forming apparatus.

FIG. 4 is a partially sectional perspective view showing a processing container and a lid according to the present invention.

FIG. 5 is a cross-sectional view showing different modifications of the tip of the resist solution supply nozzle according to the present invention.

FIG. 6 is an enlarged perspective view showing a jet head used in a coating film forming apparatus.

FIG. 7 is a sectional view of a jet head.

FIG. 8 is a flowchart for explaining a method of forming a resist film using a coating film forming apparatus.

FIG. 9 is a perspective view schematically showing an entire resist coating / developing system to which the coating film forming apparatus is applied.

FIG. 10 is a perspective view showing a modification of the jet head.

FIG. 11 is a sectional view showing a modified example of the jet head.

FIG. 12 is a sectional view showing another modified example of the nozzle assembly of the jet head.

FIG. 13 is a sectional view showing still another modified example of the nozzle assembly of the jet head.

FIG. 14 is a sectional view showing still another modified example of the nozzle assembly of the jet head.

FIG. 15 is a perspective view showing a modified example of the nozzle assembly and an LCD substrate which is a coating film forming body.

FIG. 16 is a graph showing the relationship between the number of rotations of the substrate and the amount of resist necessary to coat the entire surface of the substrate.

FIG. 17 is a graph showing a variation range of the thickness of the resist film from the relationship of the number of rotations of the substrate.

FIG. 18 is a graph showing the relationship between the discharge time of a resist solution and the number of rotations of a substrate.

FIG. 19 is a graph showing the relationship between the amount of solvent used and the number of rotations of the substrate.

FIG. 20 is an explanatory diagram showing another example of the droplet dropping method.

[Explanation of symbols]

Reference Signs List 10 spin chuck 12 rotating cup (processing container) 16 lid 18a opening 18A lid 20 robot arm (lid moving means) 21 drive motor 40 solvent supply nozzle (solvent supply means) 50 resist liquid supply nozzle (coating liquid supply means) 52 Resist liquid tank (coating liquid supply source) 57 Bellows pump 59 Stepping motor 70 Scanning mechanism (moving means of solvent / coating liquid supply means) 80 Main arm (transport mechanism) 107 Coating processing device (coating mechanism) 108 Coating film removing device ( Coating film removal mechanism) G LCD substrate (substrate) A Solvent B Resist liquid (coating liquid)

Continued on the front page (72) Inventor Kimio Motoda 2655 Tsukure, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture Tokyo Electron Kyushu Co., Ltd. Electron Kyushu Co., Ltd. Kumamoto Office (72) Inventor Oden Den Tokyo Electron Co., Ltd. 2-3-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo (56) References JP 4-349969 (JP, A) JP JP-A-5-259052 (JP, A) JP-A-6-210230 (JP, A) JP-A-61-150332 (JP, A) JP-A-3-76109 (JP, A) JP-A-1-173719 (JP) , A)

Claims (16)

(57) [Claims] 1. A method for forming a coating film by supplying a coating liquid on one surface of a substrate accommodated in a processing container, comprising: applying a solvent on one surface of the substrate; In a region where is applied, under a state where the solvent is not dried, a predetermined amount of the coating liquid is supplied, rotated at a first rotation speed, and diffused over the entire surface of the substrate; Closing the lid in the processing container and enclosing the substrate in the processing container; and placing the processing container and the substrate with the lid closed in the first container .
Rotating the film at a second rotation speed higher than the rotation speed to adjust the thickness of the coating film. 2. The method for forming a coating film according to claim 1, wherein the substrate and the processing container are rotated together. 3. The method according to claim 1, wherein the amount of the coating liquid is set according to the first rotation speed of the substrate. 4. The method for forming a coating film according to claim 3, wherein the amount of the coating solution and the number of rotations of the substrate are set such that a variation in the thickness of the coating film is about ± 2% or less of the average film thickness. A method for forming a coating film, characterized by being performed. 5. The method according to claim 1, wherein the application of the solvent is performed by rotating the substrate. 6. The coating film forming method according to claim 5, wherein the rotation speed of the solvent application performed by rotating the substrate is different from the first rotation speed and the second rotation speed. Forming method. 7. The method for forming a coating film according to claim 1, wherein a solvent of a coating solution is applied as the solvent. 8. The method for forming a coating film according to claim 1, wherein a coating liquid is supplied to substantially the center of the substrate. 9. A substrate supporting means for supporting one side of a substrate upward, and applying the substrate supporting means over the entire surface of the substrate.
Adjust the first rotation speed and the thickness of the coating film to diffuse the liquid.
A substrate rotating means for rotating at a second rotation speed higher than the first rotation speed, a cup-shaped processing container surrounding the substrate, a lid for closing an opening of the processing container, A solvent supply unit that supplies a solvent of the coating liquid to the substrate; a coating liquid supply unit that supplies the coating liquid to the substrate; a solvent supply unit that supports the solvent supply unit and the coating liquid supply unit; An apparatus for forming a coating film, comprising: means for movably supporting a liquid supply means between a supply position above a substrate and a standby position deviating from the supply position. 10. A substrate supporting means for supporting one side of a substrate facing upward, and the substrate supporting means is provided on an entire surface of the substrate.
The first number of revolutions to spread the coating solution over
The second rotation at a higher speed than the first rotation speed to adjust the film thickness
Substrate rotating means for rotating at a number of rotations, a processing vessel having a cup shape surrounding the substrate, a lid for closing an opening of the processing vessel, and a solvent supply means for supplying a solvent of a coating liquid to the substrate; A coating liquid supply unit for supplying a coating liquid to the substrate, the solvent supply unit and the coating liquid supply unit are supported, and the supported solvent supply unit and the coating liquid supply unit are supplied to a supply position above the substrate; A coating mechanism having means for movably supporting between a standby position deviated from the position, and a coating film removal for removing a coating film attached to an edge of the substrate on which a coating film is formed by the coating mechanism. A coating film forming apparatus comprising a mechanism. 11. The coating film forming apparatus according to claim 9, further comprising a container rotating means for rotating the processing container together with the substrate. 12. The coating film forming apparatus according to claim 9, wherein the coating liquid supply means and a coating liquid supply source for storing the coating liquid communicate with each other via a supply pipe. And a pump means capable of adjusting the supply amount of the coating liquid. 13. The coating film forming apparatus according to claim 9 , wherein at least one of the solvent supply means and the coating liquid supply means is provided with a temperature adjusting means. apparatus. 14. The coating film forming apparatus according to claim 9, wherein the lid for closing the opening is movable between a closed position of the processing container and a standby position separated from the processing container. An apparatus for forming a coating film, comprising: a lid moving means for supporting the coating film. 15. The coating film forming apparatus according to claim 9, wherein the lid is provided with an opening for supplying a solvent and a coating liquid to the substrate in the processing container, and the opening is formed on the lid. A coating film forming apparatus characterized by being formed so as to be able to be closed. 16. The coating film forming apparatus according to claim 10 , further comprising a transport mechanism for loading the substrate into the coating mechanism and transporting the substrate from the coating film removing mechanism.