JP3504092B2 - Coating liquid application method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to SOG (Spin On) for semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal display devices, substrates for optical disks, etc. (hereinafter simply referred to as substrates). (Glass, also called silica-based film-forming material) liquid, photoresist liquid, coating liquid coating method for coating a coating liquid such as polyimide resin, in particular, by supplying the coating liquid to the surface of the substrate to form a coating film having a desired film thickness. Related to forming technology.

[0002]

2. Description of the Related Art A conventional coating liquid coating method of this type will be described by taking an apparatus shown in FIG. 16 as an example. This drawing shows the main part of the rotary substrate coating apparatus, and a suction spin chuck 10 for supporting and rotating the substrate W in a substantially horizontal posture.
And a discharge nozzle 3 for supplying a photoresist liquid, which is a coating liquid, to the surface of the substrate W, almost above the center of rotation.
It has 0 and.

In the apparatus thus constructed, the rotation speed is controlled as shown in the time chart of FIG. 17 to obtain a photoresist film having a desired film thickness on the surface of the substrate W.

That is, first, the suction type spin chuck 1
0 is rotationally driven by a motor (not shown) to rotate the substrate W at a predetermined rotational speed R1 (for example, 900 rpm). When the rotation is stabilized, the photoresist liquid R is started to be discharged from the discharge nozzle 30 at a substantially constant flow rate (reference numeral t _{S in} FIG. 17), and the photoresist liquid R is continuously supplied near the rotation center of the substrate W. . And photoresist liquid R
When a predetermined time elapses from the supply start time t _{S of}
The supply of the photoresist liquid R is stopped at the reference numeral t _E ). Then, the rotation number of the suction spin chuck 10 is set to a rotation number R2 (for example, 3,000) higher than the current rotation number R1.
0 rpm) and keeping this for a predetermined time, the surplus photoresist liquid R supplied to the surface of the substrate W is shaken off and a photoresist film having a desired film thickness is formed on the surface of the substrate W. There is.

In the conventional method as described above, the photoresist film is formed by the behavior of the photoresist solution R as shown in the schematic views of FIGS. 18 (a) to 18 (f). In these figures, the substrate W is simply indicated by a circle, the photoresist liquid R is indicated by a hatched region, and the rotation speed of the substrate W in each figure is schematically indicated by the size of the arrow.

First, in a state immediately after starting to supply the photoresist solution R to the surface of the substrate W while rotating the substrate W at a low speed R1 at low speed, the photoresist solution R has a circular mass R _a (in plan view). hereinafter, this is referred to as the core R _a) to be in the vicinity of the rotation center of the substrate W becomes. Further photoresist liquid R
As the core R _a continues to be supplied, the diameter of the core R _a is concentrically expanded toward the peripheral edge of the substrate W while maintaining a substantially circular shape due to the centrifugal force accompanying the rotation.

The core R _a remains circular for a while (several seconds), but after that, the shape is largely changed. Specifically, as shown in FIG. 18A, this circular core R
_A large number of elongated photoresist liquids R _b (hereinafter, referred to as mustache R _b ) start to radially extend from the peripheral portion of a toward the peripheral portion of the substrate W. This many mustache R
_b is continue to grow towards the periphery of the substrate W with the expansion of the diameter of the core R _a by a centrifugal force, beard R _b core R
_{Since the} radius of gyration is larger than that of _a and centrifugal force is applied to it for a larger extent, the core R _a extends toward the peripheral edge of the substrate W faster than the diameter of the core R _a increases (FIG. 18).
(B)).

Further, the rotation of the substrate W is continued at the rotation speed R1 (at this time, the photoresist liquid R is also continuously supplied).
Then, as shown in FIG. 18C, the tips of the many mustaches R _b reach the peripheral edge of the substrate W. When a large number of whiskers R _b reach the peripheral portion of the substrate W in this way, the photoresist liquid R reaches the peripheral portion of the substrate W from the core R _a through the beard R _b and is scattered (scattered photoresist liquid R _c ). Furthermore the width of the beard R _b is expanded along with the diameter of the core R _a is increased by (FIG. 18 (c) and the two-dot chain line in FIG. 18 (d)), beard R _b which is not covered with the photoresist solution R The area between them is gradually reduced and the entire surface of the substrate W is covered with the photoresist solution R (core _Ra , beard _Rb ) (FIG. 18E). At this point, the time is set in advance so that the discharge of the photoresist liquid R from the discharge nozzle 30 is stopped (reference numeral t _{E in} FIG. 17).

As described above, after the entire surface of the substrate W is covered with the photoresist solution R, the surface of the substrate W is covered with the rotational speed of the substrate W set to a rotational speed R2 higher than the current rotational speed R1. By shaking off the surplus photoresist liquid R (excess photoresist liquid R _d ), a photoresist film R ′ having a desired film thickness is formed on the surface of the substrate W.

[0010]

However, the above-mentioned conventional method has the following problems. That is, as shown in FIG. 18C, when many mustaches R _b reach the peripheral edge of the substrate W, most of the photoresist solution R supplied thereafter passes from the core _Ra to the mustache R _b . And is scattered around the substrate W and scattered (scattered photoresist liquid R _c ). Therefore, it is necessary to supply a large amount of the photoresist liquid R until the entire surface of the substrate W is covered with the photoresist liquid R, which causes a problem that the amount of the photoresist liquid used becomes extremely large. That is, there is a problem that the utilization efficiency of the photoresist solution R is extremely low when a photoresist film having a desired film thickness is obtained. By the way, since the coating liquid such as the photoresist liquid is very expensive as compared with the processing liquid such as the developing liquid and the rinse liquid, it is important to reduce the amount of the unnecessary coating liquid to be scattered when manufacturing the semiconductor device or the like. This is an important issue in reducing costs.

The present invention has been made in view of such circumstances, and a desired film is obtained by applying a solvent prior to application of a coating solution and devising control of the number of revolutions at the time of applying the coating solution. An object of the present invention is to provide a coating liquid coating method capable of extremely reducing the amount of coating liquid supplied to obtain a thick coating film.

[0012]

The present invention has the following constitution in order to achieve such an object. That is, a first aspect of the present invention, by supplying a coating solution to the surface of the substrate a coating solution coating method for forming a desired film thickness of the coating film, the state or the solvent was stationary (a) a substrate Companion
The process of supplying the solvent in the vicinity of the center of the surface of the substrate in the state of being rotated at the first rotation speed for supplying, and (b) spreading the solvent.
Rotating the substrate at a second rotational speed to disperse ,
A step of diffusing the solvent supplied to the surface of the substrate over the entire surface, and (c) a state in which the substrate is stationary or coating.
A process of supplying the coating liquid in the vicinity of the center of the surface of the cloth while being rotated at a third rotation speed for supplying the cloth liquid ,
(D) A fourth rotation speed of the substrate is higher than the third rotation speed before the coating liquid supplied in the step (c) spreads at the third rotation speed to cover the entire surface of the substrate. The process of increasing the rotation speed of the substrate to (e) the rotation speed of the substrate.
Hold for a predetermined time at the fifth speed to adjust the thickness ,
The step of adjusting the film thickness of the coating film covering the entire surface of the substrate is performed in that order.

The invention described in claim 2 is the same as claim 1
In the coating liquid coating method described in (3), the coating liquid supplied in the step (c) is started to be supplied while the substrate is rotated at the third rotation speed, and the supply is completed in that state. It is a feature.

The invention described in claim 3 is the same as claim 1
In the coating liquid coating method described in (3), the coating liquid supplied in the step (c) is started in a state where the substrate is stationary, and the supply is completed in that state. .

The invention described in claim 4 is the same as that of claim 1.
In the coating liquid coating method described in (3), after the coating liquid supplied in the step (c) is started while the substrate is stationary and the rotation speed of the substrate is started to increase to the third rotation speed. The feature is that the supply is completed.

Further, the invention according to claim 5 is a coating solution coating method for forming a coating film having a desired film thickness by supplying a coating solution onto the surface of a substrate, wherein (a) the substrate is stationary. or solvent in a first state of being rotated at a rotational speed for supplying a step of supplying the solvent near the surface center of the substrate, the second rotational speed to diffuse (b) solvent
Rotating the substrate to diffuse the solvent supplied to the surface of the substrate over the entire surface, and (c) rotating the substrate in a stationary state or at a third rotation speed for supplying the coating liquid. In a state where the coating liquid is supplied to the vicinity of the center of the surface, and (d) before the coating liquid supplied in the process (c) spreads at the third rotation speed to cover the entire surface of the substrate, A step of reducing the rotation speed of the substrate to a fourth rotation speed lower than the third rotation speed; and (e) the coating liquid supplied in the step (c) spreads to cover the entire surface of the substrate. First, the rotation speed of the substrate is set to be smaller than the fourth rotation speed.
The process of increasing the rotation speed to the higher fifth rotation speed, and (f) maintaining the rotation speed of the substrate at the sixth rotation speed for adjusting the film thickness for a predetermined time, so that the entire surface of the substrate is covered. The process of adjusting the film thickness of the coating film covering is performed in that order, and the coating liquid is continuously supplied at least during the process (d).

The invention according to claim 6 is the same as claim 5
In the coating liquid coating method described in (3), the supply of the coating liquid supplied in the step (c) is started in a state where the substrate is rotated at a third rotation speed, and the rotation speed of the substrate in the step (e). Is characterized in that the supply is completed at the time when the rotation speed is started to increase to the fifth speed.

The invention described in claim 7 is the same as claim 5
In the coating liquid coating method described in (1), the coating liquid supplied in the step (c) is started while the substrate is stationary, and the rotation speed of the substrate is changed to a fifth rotation speed in the step (e). The feature is that the supply is completed at the time when it is started to increase.

[0019]

The operation of the invention described in claim 1 is as follows. First, before supplying the coating liquid to the surface of the substrate, a solvent is supplied to the vicinity of the center of the surface of the substrate (step (a)), and the substrate is rotated at a second rotation speed to remove the solvent over the entire surface of the substrate. (Step (b)). By thus coating the solvent before applying the coating liquid, the contact angle of the coating liquid with the substrate surface can be made small, so that when the coating liquid is subsequently supplied to the substrate, Thus, the coating liquid can spread very smoothly.

After the coating of the solvent is completed, the coating liquid is supplied to the vicinity of the center of the surface of the substrate while the substrate is stationary or rotated at the third rotation speed (step (c)). When the coating liquid spreads at the third rotation speed,
As shown in FIGS. 18A to 18F, first, _a large number of elongated beards R _{b start} to radially extend from the core Ra of the circular coating solution toward the peripheral portion of the substrate W (FIG. 18).
(A), (b)) When these whiskers R _b reach the peripheral portion of the substrate W (FIG. 18 (c)), the coating liquid passes through them and becomes the scattering coating liquid R _c around the substrate W. (See FIGS. 18 (c) and 18 (d)), the amount of unnecessary coating liquid becomes extremely large. Therefore, before the coating liquid supplied to the surface of the substrate W spreads at the third rotation speed and covers the entire surface of the substrate W, the rotation speed of the substrate is increased to the fourth rotation speed (step (d )).

For example, as shown in FIG.
The surface state of the substrate W as shown in (b), that is, the core R
_A case will be described in which the rotation speed of the substrate W is increased from the third rotation speed to the fourth rotation speed in the state where the beard R _b starts to extend from a. When the rotation speed is controlled in this manner, the coating liquid behaves as shown in FIG.

First, the rotation speed is the third rotation as in the conventional example.
If the number remains as it is, it is indicated by hatching in Fig. 4.
Area core R_a/ Beard R_bFrom the state of, as shown by the chain double-dashed line
To core R_a/ Beard R_bCentrifuge toward the peripheral edge of the substrate W
Expands / stretches by force, but here the number of rotations is the 4th rotation
As you increase to a number (accelerate), the beard R_bInertia
A force, that is, a force opposite to the rotation direction acts. But
Therefore, due to the combined force of centrifugal force and inertial force,_bIs circumferential
The width expands so that it can be bent to
Causes its tip to extend toward the peripheral edge (see Fig. 4
Dotted line), core R _aThe diameter of will also increase. Only
Also, the solvent is applied to the entire surface of the substrate W prior to applying the coating liquid.
As it is applied, it mustache R due to inertial force._bIs easily large
It can be bent in the circumferential direction. It is omitted in the schematic diagram
As a result of applying solvent to the
R_bWith a narrow bead and more beard R than the conventional example_b
Occurs. Furthermore, core R_aThe expansion of the diameter of the
It will be faster than that.

As a result, the beard R _b not only extends toward the peripheral edge of the substrate W, but also widens its width in the circumferential direction, so that the beard R _b must reach the peripheral edge of the substrate W. The gap between R _b is rapidly narrowed, and the time required for the coating liquid to cover the entire surface of the substrate W (coating required time) can be shortened. This short coating time means that
This means that the time from when the supply of the coating liquid is started until the coating liquid covers the entire surface of the substrate W and the supply of the coating liquid is stopped is short. In other words, the time from when the beard R _b reaches the peripheral portion of the substrate W to when the supply of the coating liquid is stopped is shortened, and thus the amount of the coating liquid scattered from the peripheral portion of the substrate W through the beard R _b is reduced. Since the amount becomes small, it is necessary to hold the substrate at the fifth rotation speed for a predetermined time after that (step (e)) and shake off the excess coating solution to form a coating film having a desired film thickness. The amount of coating liquid can be reduced.

According to the second aspect of the invention, the so-called "dynamic method" is used in which the supply of the coating liquid is started while the substrate is rotated at the third rotation speed and the supply is completed in that state. Even in the case of supplying the liquid, by increasing the rotation speed of the substrate to the fourth rotation speed before the coating liquid spreads at the third rotation speed and covers the entire surface of the substrate, The same action occurs and the coating required time can be shortened. Therefore, the amount of the coating liquid scattered can be reduced.

According to the third aspect of the invention, the coating liquid is started by the so-called "static method" in which the supply of the coating liquid is started with the substrate being stationary and the supply of the coating liquid is completed in that state. Even when supplying the coating liquid, the coating required time is increased by increasing the rotation speed of the substrate to the fourth rotation speed before the coating liquid spreads by the third rotation speed to cover the entire surface of the substrate. Can be shortened. Therefore, the amount of the coating liquid scattered can be reduced.

According to the fourth aspect of the invention, the supply of the coating liquid is started with the substrate stationary, and the supply of the coating liquid is started after the number of rotations of the substrate is increased to the third number of rotations. Even when the method for supplying the coating liquid, which is completed by combining the static method and the dynamic method described above (hereinafter, this supplying method is referred to as "stamic method"), the coating liquid is spread by the third rotation speed. The coating required time can be shortened by increasing the rotation speed of the substrate to the fourth rotation speed before covering the entire surface of the substrate. Therefore, the amount of the coating liquid scattered can be reduced.

The operation of the invention described in claim 5 is as follows. First, before supplying the coating liquid to the surface of the substrate, a solvent is supplied to the vicinity of the center of the surface of the substrate (step (a)), and the substrate is rotated at a second rotation speed to remove the solvent over the entire surface of the substrate. (Step (b)). By thus coating the solvent before applying the coating liquid, the contact angle of the coating liquid with the substrate surface can be made small, so that when the coating liquid is subsequently supplied to the substrate, Thus, the coating liquid can spread very smoothly.

After the coating of the solvent is completed, the coating liquid is supplied near the center of the surface of the substrate while the substrate is stationary or rotated at the third rotation speed (step (c)). When the coating liquid spreads at the third rotation speed,
As described above, a large number of elongated beards R _b radially extend from the core R _a toward the peripheral edge of the substrate W (FIG. 18A,
(B)), when these reach the peripheral portion of the substrate W, the coating liquid becomes a scattering coating liquid _Rc and scatters (Fig. 18 (c),
Since (d)), the amount of unnecessary coating liquid becomes extremely large.

Therefore, before the coating liquid supplied to the surface of the substrate W spreads at the third rotation speed and covers the entire surface of the substrate W, the rotation speed of the substrate W is set lower than the third rotation speed. Four
Is temporarily reduced to the number of revolutions (step (d)). That is, as shown in FIG. 18A, the coating liquid R in which the core R _a and the beard R _b are canceled out from the state where the core R _a keeps the circular shape as shown in FIG. Before covering the entire surface, the rotation speed of the substrate W is temporarily reduced to a fourth rotation speed lower than the third rotation speed.

For example, as shown in FIG.
It will be described that reduces the rotational speed from the third speed to the fourth speed in a state in which the beard R _b is extended from _a. The fourth rotation speed also includes the rotation speed = 0, that is, the state in which the rotation of the substrate is stopped.
When the rotation speed is controlled in this way, the coating liquid behaves as shown in the schematic diagrams of FIGS. 7 to 10. 7 and 8 are side views schematically showing the substrate W and the coating liquid R, and FIGS. 9 and 10 are plan views schematically showing the substrate W and the coating liquid R.

[0031] First, when decelerated to a fourth rotational speed lower than the rotating speed of the substrate W third speed expansion and extend temporarily substantially stops of beards R _b in the diameter of the core R _a of the substrate W It becomes a state. At least in this state still so continues to supply the coating liquid, it is possible to increase the amount of the coating liquid R core R _a as compared to the core R _a prior deceleration (Fig. 7) (Fig. 8). Thus state liquid amount of the coating liquid R core R _a is increased, that is, in a state where expansion momentum of the core R _a is increased, before covering the entire surface of the substrate W is a coating liquid, the rotational speed of the substrate The substrate is rotationally driven again only after increasing the rotation speed to a fifth rotation speed higher than the fourth rotation speed (step (e)). Then, the coating liquid R behaves as shown in FIGS. 9 and 10.

Assuming that the number of rotations is maintained as in the conventional example, from the state of core R _a / bald R _b shown by hatching in FIG. 9, the core R _a / bald R _b becomes the substrate as shown by the chain double-dashed line. Linear expansion toward the peripheral edge of W by centrifugal force /
Extend. Further liquid volume increased core R _a new radial coating liquid flow (hereinafter, new fingers R _b 'hereinafter) is generated, new fingers R _b from between the plurality of beard R _b' is a substrate It begins to extend toward the periphery of W.

Therefore, when the number of revolutions is increased from the fourth number of revolutions to the fifth number of revolutions, inertial force is applied to the mustache R _b and the new mustache R _b 'through the state shown in FIG. 9 in the process.
That is, a force in the direction opposite to the rotation direction acts. Therefore, due to the combined force of the centrifugal force and the inertial force, the mustache R _b and the new mustache R _b have their widths expanded so as to be bent in the circumferential direction as shown by the dotted line in FIG. Extending toward the peripheral edge of the substrate,
The diameter of _a will also increase. Moreover, since the solvent is applied to the entire surface of the substrate W prior to the application of the application liquid,
Due to the inertial force, the beard R _b and the new beard R _b ′ are easily bent in the large circumferential direction. Although not shown in the schematic diagram, because the solvent coating is performed, the mustache R _b and the new mustache R _b 'are thinner than the conventional example, and more beard R _b than the conventional example. And a new mustache R _b 'is generated. Further, the diameter of the core R _a is expanded faster than in the conventional example.

[0034] As a result, since the beard R _b and new fingers R _b 'as shown in FIG. 10 enlarges its width in the circumferential direction as well as extending toward the periphery of the substrate W, beard R _b There gaps between beard R _b to reach the periphery of the substrate W is narrowed rapidly to join the occurrence of new fingers R _b ',
The time required for coating until the coating liquid R covers the entire surface of the substrate W can be significantly shortened. The short coating required time means that the time from the start of the supply of the coating liquid R until the coating liquid R covers the entire surface of the substrate W and the supply thereof is stopped is short. In other words, since the amount of the coating liquid R scattered around the beard R _b (and the new beard R _b ′) as described above is reduced, the substrate is thereafter moved to the sixth rotation speed for a predetermined time. It is possible to reduce the amount of the coating liquid required for holding (step (f)) and shaking off the excess coating liquid to form a coating film having a desired film thickness.

According to the sixth aspect of the present invention, the supply of the coating liquid is started while the substrate is rotated at the third rotation speed, and after the step (d) is decelerated, the fifth rotation is performed. Even when the coating liquid is supplied by the so-called "dynamic method", in which the supply of the coating liquid is started and completed while the substrate is rotated, such that the supply is stopped when the substrate is rotated again by a certain number. by coating solution is decelerated to a fourth speed before covering the entire surface of the substrate, to finish the coating liquid increased only core R _a in a state in which almost stopped the extension of the core R _a and beard R _b You can Therefore, it is possible to while maximizing the expansion momentum of the core R _a start-up to the fifth speed faster expansion of the diameter of the core R _a, and new fingers R _b 'efficiently generating Can be made.

Further, according to the invention described in claim 7, the supply of the coating liquid is started in a state where the substrate is stationary, the deceleration of the step (d) is performed, and then the coating liquid is rotated again at the fifth rotational speed. Even when the coating liquid is supplied by the "Stamic method", which is a combination of the static method and the dynamic method, such as stopping the supply at the time of starting the coating, before the coating liquid covers the entire surface of the substrate. by decelerating the fourth speed it can finish the coating liquid increased only core R _a in a state in which almost stopped the extension of the core R _a and beard R _b. Thus, the core R because _a larger momentum of can in a maximized state starts up to the fifth speed faster expansion of the diameter of the core R _a, and new fingers R
_b'can be efficiently generated.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a rotary substrate coating apparatus to which the method of the present invention is applied.

In the figure, reference numeral 10 is a suction type spin chuck for sucking and supporting the substrate W in a substantially horizontal posture. This suction type spin chuck 10 has a hollow rotary shaft 1
The rotary motor 12 drives the rotary motor 12 to rotate around the vertical axis together with the substrate W by driving the rotary motor 12. A scattering prevention cup 13 is disposed around the suction type spin chuck 10 for preventing scattering of a coating solution such as a photoresist solution. Although not shown, the anti-scattering cup 13 and the rotary shaft 11 are configured to move up and down relatively, and the unprocessed substrate W is carried into the anti-scattering cup 13 while these are relatively moved up and down. The processed substrate W is carried out of the shatterproof cup 13.

A coating liquid discharge nozzle 30 for discharging the photoresist liquid onto the substrate W is provided above the scattering prevention cup 13 and above the rotation center of the substrate W. The coating liquid discharge nozzle 30 includes a coating liquid supply unit 31.
A photoresist liquid, which is a coating liquid, is supplied from the drive unit 32, and the drive unit 32 extends the tip end portion thereof to a supply position shown in FIG. 1 and a standby position (not shown) separated laterally from the shatterproof cup 13. It is designed to be rocked. Further, a solvent discharge nozzle 40 for discharging the solvent onto the substrate W is arranged along the coating liquid discharge nozzle 30. The solvent discharge nozzle 40 includes a solvent supply unit 41.
The solvent is supplied from the drive unit 42, and the drive unit 42 operates in the same manner as the above-described coating liquid discharge nozzle 30.
It is configured to swing and move between the supply position and the standby position shown in.

The solvent supplied by the solvent supply unit 41 is, for example, ECA (ethylene glycol monoethyl ether acetate) or MAK (methyl-2-n-amyl ketone) used as the main solvent of the photoresist liquid. ) Etc. can be used.

The above-mentioned rotary motor 12, coating liquid supply unit 31, drive unit 32, solvent supply unit 41, and drive unit 42.
And are controlled by the control unit 50.
The control unit 50 is configured to control each of the above units by a processing program stored in advance in the memory 51 according to a time chart described later.

<First Embodiment> (Claims 1 to 4)
(Dynamic method) (Example of claim 2) Next, with reference to the time chart of FIG. 2 and the schematic diagram of FIG. 3, the photoresist liquid coating process by the “dynamic method” will be described. . The processing program corresponding to this time chart is stored in advance in the memory 51 shown in FIG. 1 and is executed by the control unit 50. In addition, the substrate W to be processed has already been sucked by the spin chuck 1.
No. 0 is placed and held by suction, and the solvent discharge nozzle 4
It is assumed that 0 has been moved to the supply position by the drive unit 42. In the schematic diagram of FIG. 3, the substrate W is simply represented by a circle, and the photoresist solution is represented by a hatched region.

First, the rotational drive of the rotary motor 12 is started.
It Specifically, t₁At the time point, the rotation speed R3 (for example, 50
0 rpm) so that the control unit 50 controls the rotary motor 12
Drive forward. The rotation speed of the substrate W is R3.
When t stabilizes at_PSAt the solvent discharge nozzle 40
Starting to supply the solvent at a constant flow rate, t_PEAt the time
Stop pay. And t₃Substrate W rotates at this point
To reach a number R4 (eg 1500 rpm),
t₂At that point, the rotation speed starts to increase. This speed
R4 to t_FourRotation of the substrate W by maintaining up to the point
The solvent supplied near the center is diffused over the entire surface of the substrate W.
Let Note that the above t_PSFrom time t_PESolvent is used up to the point
Salary time T_PSUAnd the size of the substrate W and the number of rotations R described above.
3 and R4 are preset. Also, the above times
The rotation number R3 corresponds to the first rotation number of the present invention, and
The number R4 corresponds to the second rotation speed of the present invention, and t_PSFrom the moment
t _PEUp to the time point corresponds to the step (a) of the present invention, and t₂Time point
To t_FourUp to the time point corresponds to the step (b) of the present invention.

As described above, before applying the photoresist liquid
By applying a solvent to the entire surface of the substrate W,
Then the photoresist liquid supplied to the surface is extremely
It can be smoothly spread over the surface. Na
Oh, the solvent supply was stopped _PEDrive after time point
When the portion 42 moves the solvent discharge nozzle 40 to the standby position,
Instead, the drive section 32 is replaced by the coating solution discharge nozzle 30.
To the supply position.

[0045] Next, t ₅ rotates the rotational speed of the substrate W at the time the number R5 (e.g., 2000 rpm) to reach, Yuku raising the rotational speed at t ₄ time. At a time t _S of the rotation number R5 is stable, the photoresist solution at a constant flow rate from the coating solution discharge nozzle 30 starts supplying the supply of the photoresist solution at t _E time to become feed time T _SU from that point Stop. That is, the rotation speed of the substrate W is maintained at the rotation speed R5 from the time point t _{5 to the} time point t ₆ , and the supply of the photoresist solution is completed during that time (dynamic method). The rotational speed R5 described above corresponds to the third rotational speed in the present invention, and the time from t _S to t _E corresponds to the step (c) in the present invention.

In this way, the photoresist liquid supplied to the surface of the substrate W rotationally driven at the rotation speed R5 is
t The _S time the substrate W lumps R _a circular in plan view at the center of rotation near the exist become (hereinafter, referred to as core R _a) (Figure 3 (a)). The core R _a is subjected to the centrifugal force associated with the rotation speed R5 and the substrate W is maintained while maintaining its shape.
It expands concentrically toward the peripheral edge of.

Core R_aKeeps a circular shape for a while
However, after that, the shape is greatly changed as follows.
That is, this circular core R_aFrom the circumference of the substrate W
A large number of elongated photoresist liquids R toward the periphery_bof
Flow (Hereinafter, this mustache R_bCalled) extends radially
Start (FIGS. 3 (a) and 3 (b)). This many mustache R
_bIs the core R by centrifugal force_aWith the expansion of the diameter of the substrate
It continues to extend toward the periphery of W, but mustache R _bIs the core R
_aGreater centrifugal force due to larger radius than
Core R_aFaster than the expansion of the diameter of the substrate W
It extends toward the peripheral portion (FIG. 3 (b)).

Therefore, before the entire surface of the substrate W is covered with the photoresist liquid R supplied to the surface of the substrate W, the rotational speed is set to a rotational speed R6 (for example, 4000 rpm) higher than the rotational speed R5 (2000 rpm). start-up (t ₆ point in time). At this time, the rotation speed is controlled to start increasing from t ₆ and reach the rotation speed R6 at t ₇ .
During this period, for example, it is about 0.07 sec. The rotation speed R6 described above corresponds to the fourth rotation speed of the present invention, and the time points t ₆ to t ₇ correspond to the step (d).

By sharply increasing the rotation speed of the substrate W from the rotation speed R5 to the rotation speed R6 in this manner, a mustache R that should be linearly extended toward the peripheral portion of the substrate W.
_An inertial force acts on _b by the acceleration in the rotation increasing process and a centrifugal force by rotation acts on it, and the extending direction of the beard R _b is bent in the circumferential direction by the resultant force to expand its width (see FIG. 4). ). Further core R _a
Also increases in diameter (Fig. 3 (c), Fig. 4).

Since the solvent is previously applied to the entire surface of the substrate W as described above, the contact angle between R of the photoresist solution and the surface of the substrate W is very small.
Therefore, with the expansion of the diameter of the core R _a is increased in the above process, although omitted in diagram schematically, with beard R _b is thin frequently occur as compared with the conventional example, beard R _b inertial force Makes it very easy to bend.

Then, as shown in FIG.
Ge R_bWhen the tip of the substrate reaches the peripheral edge of the substrate W,
The photoresist liquid R is scattered from the periphery of the substrate W from
Scatter photoresist liquid R_c). However, due to acceleration
Rihige R_bIs bent in the circumferential direction,
Core R that expands / extends toward the edge_a/ Beard R _b
Together with the photoresist liquid R, the surface of the substrate W is
The time to cover the entire surface is much shorter than before
It is shrunk (FIGS. 3C to 3E).

[0052] Thus the entire surface of the substrate W in the covered by the photoresist solution R, rotating the rotating speed of the substrate W at t ₈ when the number R7 (e.g., 2500 rpm) is lowered to, the rotation number R7 t ₉ time by holding t to ₁₀ point from a slight excess of the photoresist solution R covering the entire surface of the substrate W (the excess photoresist solution R _d)
Shake off. As a result, a photoresist film R ′ having a desired film thickness is formed on the surface of the substrate W. The rotation number R7 described above corresponds to the rotational speed of the fifth aspect of the present invention, t from t ₈ time
Up to the _10th point corresponds to the step (e) of the present invention.

As described above, the solvent is applied to the substrate W before supplying the photoresist liquid R to reduce the contact angle between the photoresist liquid R and the surface of the substrate W. The diameter of the core R _a of the photoresist solution R supplied to the surface can be easily expanded, and the beard R _b generated from the core R _a toward the peripheral edge of the substrate W can be made small and large. Further, before the surface of the substrate W is covered with the photoresist liquid R, the rotation speed of the substrate W is changed from the rotation speed R5 (third rotation speed) to the rotation speed R6 (fourth rotation speed).
When the whisker R _b is lifted up and an inertial force is applied to it, since the contact angle is made small, a large number of thinly generated mustaches R _b are largely bent in the circumferential direction to greatly expand the width thereof. The time required for coating until the surface is covered with the photoresist liquid R can be greatly shortened. Therefore, since the time from when the beard R _b reaches the peripheral portion of the substrate W until the supply of the photoresist liquid R is stopped becomes shorter, the photoresist which is released and scattered around the substrate W through the beard R _b. The amount of the liquid R can be reduced.
As a result, the amount of the photoresist liquid R required to obtain the photoresist film R ′ having the desired film thickness can be extremely reduced.

The symbol T _a in the time chart of FIG. 2 indicates the time from the time t _S when the supply of the photoresist liquid R to the substrate W is started to the time t ₆ when the rotation speed is increased (hereinafter, rotation speed switching). It is called the start time). The rotation speed switching start time T _a needs to be set to a time before the entire surface of the substrate W is covered with the photoresist liquid R as described above. Experiments were measured 8-inch supplying photoresist solution R to the substrate W size, the variable to cover the required time T _a between the rotational speed switching variously,
Rotational speed switching start time T _a is 0.1sec~0.4sec
It has been found that the range becomes shorter than the conventional one.
Therefore, it is preferable to set the rotation speed switching start time T _a in the time chart of FIG. 2 within the above range. It should be noted that this rotation speed switching start time T _a includes the diameter of the substrate W, the flow rate of the photoresist liquid, the surface state of the substrate W, the rotation speed R5, the rotation speed R6, the supply start time t _s , the supply stop time t _{E, and the} like. It is more preferable to set in consideration of each condition.

To shorten the coating time, it is necessary to rapidly
It is preferable to increase the rotation speed. In other words, the time of Figure 2
Time point t in the chart₆From time t₇Time to
_bThe shorter (hereinafter referred to as rotation speed switching time) the shorter (acceleration
The higher the degree, the better. However, too sharp
On the contrary, the coating time is long and unnecessary photoresist
Experiments have shown that the liquid increases. Sanawa
Chi, Core R_aExtends toward the peripheral edge of the substrate W from
Mustache R_bWill be scattered due to sudden acceleration,
Rui is bent in the circumferential direction, but after that, centrifugal force is applied.
Therefore, it is possible to linearly extend toward the peripheral edge of the substrate W.
Beard R _bBecause the expansion of the width of
Seem.

Therefore, when the coating required time was measured by experiments by combining various rotation speed switching times T _b and rotation speeds R5 and R6, 7,500 to 50,000 were obtained.
It was found that good results were obtained when the acceleration was set in the range of rpm / sec. Therefore, in FIG.
It is preferable that the rotation speed switching time T _b and the rotation speeds R5 and R6 in the time chart are set in consideration of the preferable acceleration range.

In the above description, the rotation speed R5
Then, the rotational speed is rapidly increased to the rotational speed R6 to apply an inertial force to the beard _Rb , and then the rotational speed is driven at a rotational speed R7 lower than the rotational speed R6 to adjust the film thickness.
Therefore, the film thickness may be adjusted by increasing the rotation speed from R6 to R7 after accelerating from R6 to R6 lower than R7. Furthermore, in the above description and to change the rotational speed in one step from t ₆ time, but it may be accelerated by changing the rotational speed more than two stages.

"Static Method" (Example of Claim 3) Next, the photoresist liquid coating process by the "static method" will be described with reference to the time chart of FIG. The apparatus for carrying out this coating process is the same as that shown in FIG.
The configuration is the same as that shown in FIG. 4 and the processing programs stored in the memory 51 are different as follows.

First, the substrate W is sucked by the spin chuck 10.
In the state where the solvent is adsorbed and held on the substrate W, the solvent is started to be supplied to the surface from the solvent discharge nozzle 40 without rotating the rotation motor 12, that is, in the state where the substrate W is stationary. Then, at the time t ₁ when the solvent supply time T _PSU has elapsed, that is, when the solvent supply is completed, the rotation speed of the substrate W is increased,
Control is performed so as to reach the rotation speed R3 at time t ₂ . Then, while holding the rotation speed R3 to t ₃ time,
The solvent supplied to the surface of the substrate W begins to spread over the entire surface. The process from the time origin to the time point t ₁ corresponds to the process (a) of the present invention.

After that, at time t ₃ , the rotation speed of the substrate W is started to increase to the rotation speed R4 (second rotation speed), and the rotation speed R4 is reached.
Hold the solvent from t ₄ to t ₅ to remove the solvent from the substrate W.
Spread over the entire surface of. Then, at the time point t ₆ , the rotation speed of the substrate W is “0”, that is, the rotation of the substrate W is stopped. The process from time t _{3 to} time t ₆ corresponds to step (b) of the present invention.

After the rotation of the substrate W is completely stopped, t _S
At this point, the photoresist liquid starts to be supplied from the coating liquid discharge nozzle 30 at a constant flow rate, and the supply time T _SU elapses.
At time _E , the supply is stopped. That is, the supply of the photoresist solution is completed while the substrate W is stationary (static method). At this time, the photoresist liquid is as shown in FIG.
As shown in the schematic diagram, the diameter of the core _Ra is increased by the continuously supplied photoresist liquid while keeping the core Ra in the vicinity of the center of the substrate W and having a substantially circular shape (not shown). The process from time t _{S to} time t _E corresponds to step (c) of the present invention.

[0062] t stops the supply of the photoresist solution in _{the E} point, toward the rotational speed of the wafer W on the spin number R5 (third speed) is increased, t it from t ₇ time
After holding up to _eight times, the rotational speed of the substrate W at t ₉ time starts acceleration from t ₈ time to reach the rotational speed R6 (Fourth speed). This time point t ₈ is set before the photoresist liquid supplied to the surface of the substrate W spreads by the third rotation speed R5 and covers the entire surface of the substrate W.
The process from the time point t _{8 to the} time point t ₉ corresponds to the step (d) in the present invention.

In this process, the same behavior as the above-mentioned "dynamic method" occurs in the photoresist liquid. That is, the time t _E at which the rotation starts toward the rotation speed R5.
In the core R _a large number of whiskers R _b from the circumference portion is generated at the beginning extend toward the peripheral portion of the substrate W (FIG. 3 (b)),
By rapidly accelerating from the rotational speed R5 to the rotational speed R6, the beard R _b is largely bent in the circumferential direction while enlarging its width while receiving an inertial force (FIGS. 3C and 4). Therefore, it is possible to shorten the time required for the photoresist liquid R to cover the entire surface of the substrate W. Incidentally, on the relationship between reduce the contact angle between the substrate W surface and the photoresist solution R by applying a solvent prior to application of the photoresist solution, fast expansion of the diameter of the core R _a as compared with the prior art, The number of whiskers R _b generated is large and the width of each is narrow, as in the above-mentioned “dynamic method”.

[0064] Then, after holding the rotational speed R6 to t ₁₀ time, and holds the rotation speed from t ₁₁ time until t ₁₂ time by decreasing the number of revolutions R7 (rotational speed of the fifth) of photoresist coating thickness Adjust. By controlling the number of rotations in this way, the required coating time can be shortened, and the amount of the photoresist solution R scattered around the substrate W through the beard R _b can be reduced. Therefore, it is possible to reduce the amount of photoresist liquid required to obtain a photoresist film having a desired film thickness. In addition, from time t _{11 to} time t ₁₂
The process up to this point corresponds to step (e) of the present invention.

The reference numeral T _a 'in the time chart of FIG. 5 indicates the rotation speed R6 from the time t _E when the rotation speed of the substrate W starts to increase to the rotation speed R5 (which is almost equal to the time when the mustache R _b occurs). Is the time until the acceleration starts (hereinafter, this time is also referred to as the rotation speed switching start time in accordance with the "dynamic method"). This rotation speed switching start time T _a '
Needs to be set to the time until the entire surface of the substrate W is covered with the photoresist solution, as in the above-mentioned “dynamic method”. However, in this method, as compared with the “dynamic method”, the core R _a at the rotation start time t _E
Since the diameter of the mustache R _b is large, the time required for the beard R _b to reach the peripheral portion of the substrate W is also short. Therefore, in consideration of various conditions described in "Dynamic method" described above, it is preferable to set the rotational speed switching start time T _a 'within a short range than the rotational speed switching start time T _a.

[0066] Also, the rotational speed switching time T _b above, as the acceleration in the ranges described "dynamic method" described above is obtained, it is preferable to set the rotation number R5, R6.

Furthermore, in this "static method"
When the supply of the photoresist liquid is stopped t _EIs the time of Figure 5
The board is not limited to the time points shown in the chart,
The supply may be completed with W kept stationary. According to
At the start of supply t_SFrom R to R5
Can be set within an appropriate range up to the time of raising
Noh.

The acceleration may be carried out in two or more stages as described in the above "dynamic method". Further, in the coating process by the above-mentioned “dynamic method”, the solvent is supplied while rotating the substrate W. However, like the supply method by the “static method”, the solvent is supplied while the substrate W is stationary. It goes without saying that you may do so. Similarly, the solvent may be supplied while rotating the substrate W when applying the solvent in the “static method”.

[Stamic Method] (Example of Claim 4) Next, with reference to the time chart of FIG. 5, a photoresist liquid coating process by a “stamic method”, which is a combination of the static method and the dynamic method described above, will be described. Explain. That is, the supply of the photoresist solution is started in a state where the substrate W is stationary (the supply of the static method is started), and the supply of the photoresist solution is stopped (the supply of the dynamic method is stopped) after the substrate W starts to rotate.

Similar to the above, the solvent is applied before the application of the photoresist solution to reduce the contact angle of the photoresist solution on the surface of the substrate W. Then, the supply of the photoresist solution is started at the time t _S , and the rotation speed R is continued at the time t _E while continuing the supply of the photoresist solution.
It starts to increase to 5 (third rotation speed), and the supply is stopped at time t ₇ when the rotation speed R5 is reached. In other words, the rotation of the substrate W is started during the supply time (T _SU ). In this case, t ₇ point corresponds to step (c) in the present invention from the t _S time.

[0071] Then, before the photoresist solution covers the entire surface of the substrate W, in particular from t ₈ time t ₉ rotates the rotating speed of the substrate W during the time from the rotational frequency R5 number R6 (fourth The core R _a, which is largely concentrically spread due to the effect of the solvent application, is sharply accelerated to a large number, and the beard R _b , which is thinly generated in large numbers, is largely bent in the circumferential direction. Therefore, the amount of the photoresist liquid scattered around the substrate W through the beard R _b can be reduced. After that, the photoresist film having a desired film thickness is formed by maintaining the rotation speed R7 (fifth rotation speed) from the time point t _{11 to the} time point t ₁₂ . as a result,
"Dynamic method" and "Static method" mentioned above
Similar to the coating process by, the amount of photoresist liquid required to form a photoresist film having a desired film thickness can be reduced.

The timing for stopping the supply of the photoresist solution is not limited to the time point at which the rotation speed R5 is reached as at the time point t ₇ in FIG. 5, but at any time point after the rotation is started. It may be. For example, as indicated by a dotted arrow in FIG. 5, a time point t _E at which the rotation starts at the rotation speed R5.
It may be during the time point t ₇ from when the rotation speed reaches the rotation speed R5.

The rotation speed switching start time T _a 'and the rotation speed switching time T _b may be set according to the "static method" described above.

Further, the rotation state of the substrate W at the time of applying the solvent,
Similar to the above-mentioned "static method", the steps of changing the rotational speed during acceleration can be modified.

<Second Embodiment> (Claims 5 to 7)
Example corresponding to [Dynamic method] (Example of claim 6) Next, a method different from the method according to the first embodiment described above will be described with reference to the time chart of FIG. The difference from the first embodiment is that the rotation of the substrate W is temporarily “decelerated” after the supply of the photoresist liquid to the substrate W is started. Since the device configuration is the same as that described above, its description is omitted.

First, the rotational drive of the rotary motor 12 is started at the time origin, and the rotational speed R3 (for example, 500 rpm, which corresponds to the first rotational speed) at time t _1.
Control to reach. Time t when the rotation speed becomes stable at R3
_The supply of the solvent from the solvent discharge nozzle 40 is started from _PS , and the supply is stopped at the time t _PE when the solvent supply time T _PSU has elapsed. After that, at time t ₃ , the substrate W rotates at the rotation speed R4 (for example,
1500 rpm, which corresponds to the second number of revolutions), and starts increasing the number of revolutions at time t ₂ . The solvent is diffused over the entire surface of the substrate W by maintaining this rotation speed R4 until time t ₄ . The effect of this solvent is as described above. The process from time t _{PS to} time t _PE corresponds to the process (a) of the present invention, and the process from time t _{3 to} time t ₄ corresponds to the process (b) of the present invention.

[0077] In the time t ₄ when prior to application of the solvent is completed started raising the rotational speed, t ₅ rotates at several R5 (e.g., 20
00 rpm, which corresponds to the third rotation speed of the present invention)
Control to reach. At a time t _S when the rotation speed R5 becomes stable, the supply of the photoresist liquid from the coating liquid discharge nozzle 40 to the vicinity of the rotation center of the substrate W is started at a constant flow rate. The supplied photoresist liquid R concentrically expands the diameter of the core R _a by the centrifugal force associated with the rotation as described above (FIG. 3A), and the beard R from the circumferential portion.
_b begins to extend (Fig. 3 (b)). Thus before covering the entire surface of the photoresist solution R spreads the substrate W, in particular the start of deceleration from t ₆ time, the rotation is lower than the rotational speed R5 at t ₇ when the number R6 (e.g., 0 rpm,
The speed is reduced so as to reach the fourth rotation speed of the present invention). In this example, since the rotation speed R6 is "0", the substrate W is stationary. This deceleration (stop) state is t _E
Keep up to the point. The process from the time point t _{7 to the} time point t _E corresponds to the step (d) of the present invention.

Immediately after starting the supply of the photoresist liquid at the time t _s , the photoresist liquid exists as the core R _{a in the} vicinity of the rotation center of the substrate W. Further continuing the supply of the photoresist solution R, the diameter of the core R _a is slide into expanded concentrically towards the periphery of the substrate W while substantially maintaining the circular centrifugal force acts due to the rotational frequency R5 . Since the solvent is applied in advance, the diameter is expanded faster than in the conventional example.

The core R _a remains circular for _a while, but as shown in FIGS. 3A and 3B, the centrifugal force of the rotation speed R5 causes the core W to move from the circumference of the core R _a to the substrate W. A large number of whiskers R _b are generated and begin to extend toward the peripheral edge of the. This beard R
As described above, _b is larger and thinner than before due to the action of the solvent, and the beard R _b extends toward the peripheral edge faster than the core R _a as described above.
A side view showing this state is a schematic view of FIG. 7.

As described above, it is supplied to the surface of the substrate W.
The entire surface of the substrate W is
The substrate W is kept stationary (rotated at a rotation speed R6 = 0) before being covered.
And let the core R_aRadial emission from the circumference of
Ge R_bExtension and core R_aTemporarily stops the expansion of the diameter
Can be made. In this state,
Since the supply of the distant liquid R is continuing,
As shown, core R_aOnly the amount of photoresist liquid R
Can be increased. Core R _aLiquid volume
Increases, the core R_aTo increase the momentum
Become.

With the expanding momentum of the core R _a thus increased, the rotation speed R when the substrate W is supplied as in the conventional example.
When the photoresist liquid R continues to rotate at 5, the behavior of the photoresist liquid R is as follows. That is, from the state of the core _Ra / beard _Rb shown by hatching in FIG. 9, the core _Ra / beard _Rb linearly expands toward the peripheral portion of the substrate W by the centrifugal force as shown by the chain double-dashed line. A new radial photoresist liquid flow R _b (hereinafter referred to as a new beard R _b ) is generated from the core R _a in which the liquid amount increases and the expansion momentum increases as the liquid amount increases. new fingers R _b from between the beard R _b starts linearly extend toward the peripheral portion of the substrate W.

Then, the photoresist solution R is applied to the surface of the substrate W.
Before covering the entire surface, specifically t_ERotation of substrate W at time
The number of revolutions is from R6 (= 0 rpm) to R7 (for example,
For example, it is 4000 rpm, which corresponds to the fifth speed of the present invention.
Hit), t₈Reached R7 at that time
Accelerate rapidly as you do. Start acceleration and t
_SSupply time T from time_SUIs set to
T_EAt this point, the supply of the photoresist solution R is also stopped. This
To start accelerating_ESupply of photoresist liquid R at this point
Core R by stopping_aMaximizes momentum
The following effects are applied to the photoresist solution R in
You can get a new beard R_bEfficiently
In addition to being able to_aFaster diameter
Can be expanded. Note that t_SFrom time t_EUntil time
Corresponds to step (c) of the present invention, and t_EFrom time t₈Time
The process up to this point corresponds to step (e) of the present invention.

That is, the inertial force, that is, the force in the direction opposite to the rotation direction acts on the mustache R _b and the new mustache R _b ′ through the state shown in FIG. Therefore, due to the combined force of the centrifugal force and the inertial force, the mustache R _b and the new mustache R _b ′ have their widths expanded so as to be largely bent in the circumferential direction as shown in FIGS. The tip portion extends toward the peripheral portion of the substrate W. Further, it becomes possible to enlarge the diameter of which together with the core R _a. Since the solvent is applied in advance, the beard R _b and the new beard R _b ′ are largely bent in the circumferential direction as compared with the conventional one, and the width thereof is greatly expanded.

Then, as shown in FIG.
R_bAnd many new mustache R_b′ Tip of the substrate W
When they reach the peripheral edge, they are exposed to the photo around the substrate W.
The resist solution R is scattered (scattered photoresist solution
R_c). However, due to acceleration, mustache R_bAnd new
Tana mustache R_b’Is greatly bent in the circumferential direction,
Core R expanding / expanding toward the peripheral edge of the substrate W_a
/ New mustache R_b’/ Core R _aTogether, photo
Until the entire surface of the substrate W is covered with the resist solution R
The coating time is greatly reduced compared to the conventional case (Fig. 1
2 to 14).

While producing such an action, the substrate W is rotated from the rotation speed R7 to the rotation speed R from the time point t _{9 to the} time point t _10.
8 (e.g., a 3000 rpm, 6 corresponds to the rotational speed of the present invention) reduced to, by holding the rotational speed R8 to t ₁₁ time, substrate shake off a slight excess covering the surface A photoresist film having a desired film thickness is formed on the entire surface of W. The time points from t ₁₀ to t ₁₁ correspond to step (f) in the present invention.

As described above, the solvent is applied prior to the application of the photoresist solution to reduce the contact angle between the photoresist solution and the surface of the substrate W. Therefore, after that, the solvent is applied to the surface of the substrate W. The diameter of the core R _a of the photoresist liquid can be easily expanded. Further, before the entire surface of the substrate W is covered with the photoresist liquid R, the rotation of the substrate is temporarily stopped to increase the diameter of the core R _a and the extension of the beard R _b to stop the photoresist liquid. By increasing the expansion momentum and rapidly accelerating, it is possible to easily generate many new thin beards R _b '. Further, since strong inertial force is applied to these new mustache R _b 'and beard R _b , the width is expanded while being bent in the circumferential direction, but at this time, it is bent in the circumferential direction faster by the action of the solvent. The range will expand rapidly. Therefore, the amount of the photoresist solution that the beard R _b (and the new beard R _b ′) reaches the peripheral portion of the substrate W and is discharged / scattered to the periphery can be reduced, and the photoresist film having a desired film thickness can be formed. The amount of photoresist solution required to obtain it can be made extremely small.

The rotation speed switching start time T _a 'and the rotation speed switching time T _b are set in consideration of the deceleration (stop) period t _{7 to} t _E in addition to the various conditions described above. do it.

The symbol T _c in FIG. 6 is the time from the time t _S when the supply of the photoresist liquid R is started to the time t ₇ when the deceleration is completed (hereinafter referred to as deceleration start time). The deceleration start time T _c may be set within the time until the supplied photoresist liquid covers the entire surface of the substrate W, but the various conditions described above and the photoresist liquid R
Number of revolutions R5 at which the supply of the engine is started, and the number of revolutions switching start time T _a '
It is preferable to set in consideration of the above.

In this embodiment, the core R_aExpansion of luck
During deceleration (t ₇~ T_E)
It is important to continue supplying the photoresist solution,
When the deceleration ends as in the example above (that is, during acceleration)
Point t_E), It is not necessary to stop the supply at the same time.
Dotted arrow and supply time (T_SU) Deceleration period as shown by
Beyond the acceleration period (t_E~ T₈) In the middle of photoregis
It is also possible to stop the supply of the solution R.

In the above example, the solvent is supplied while rotating the substrate W, but as will be described later, the substrate W is
The solvent may be supplied in a stationary state.

The coating process according to the second embodiment is
The characteristic feature is that the photoresist solution R is decelerated by the rotation before it covers the entire surface of the substrate W. Therefore, the "static method" is used to start and stop the supply of the photoresist solution R while the substrate W is stationary. There is no treatment. Therefore, next, a stamic method in which the static method and the dynamic method are combined will be described with reference to the time chart of FIG.

"Stamic method" (Example of claim 7) First, at the time origin, melt the substrate W in a stationary state.
The supply of the solvent to the surface of the medium discharge nozzle 40 is started.
And the solvent supply time T_PSUTime t has passed ₁, Tsuma
When the solvent supply is completed, the rotation speed of the substrate W is increased.
Time t₂Control to reach rotational speed R3 at
It Then, this rotation speed R3 is t₃Hold up to the board
The solvent supplied to the surface of W begins to spread over the entire surface
It From the time origin, t₁Up to the process (a) of the present invention
Equivalent to.

[0093] Thereafter, the substrate W at t ₄ time starts accelerating at t ₃ time to reach the rotation speed R4, holds the rotation number R4 to t ₅ point solvent on the entire surface of the substrate W Spread. Then, at time t ₆ , the substrate W
To stop the rotation of. The process from time t _{4 to} time t ₅ corresponds to step (b) of the present invention.

[0094] After the substrate W is stationary, to start the supply of the photoresist solution from the coating solution discharge nozzle 30 at t _S time. Then, at time t ₈ t
_After starting to increase the rotation speed at time ₇ and maintaining this rotation speed R5 until time t ₉ , the rotation speed R6 (for example, 100 rpm, at the time t ₁₀ before the supply time T _SU elapses. (Corresponding to the number of revolutions of the).
This decelerated state is supplied from the supply start time t _S to the supply time T
_It is maintained up to the time t _E when _SU elapses, the supply of the photoresist liquid is stopped, and the speed is rapidly accelerated toward the rotation speed R7 (corresponding to the sixth rotation speed). The deceleration period t
_{10 to} t _E and the acceleration period t _{E to} t ₁₁ are set before the photoresist liquid spreads and covers the entire surface of the substrate W. Further, the time t _{S to the} time t _E corresponds to the process (c) of the present invention, the time t _{10 to the} time T _E corresponds to the process (d) of the present invention, and the time t _{E to the} time t ₁₁ The process up to this point corresponds to step (e) of the present invention.

Thus, the surface of the substrate W was supplied.
The photoresist solution is the same as the "first embodiment" described above.
Core R like “Mick method”_aWhisker R while expanding the diameter of_bBut
Occurs (see FIGS. 3A and 3B). Furthermore, at that time
By decelerating at the point (rotation speed R6 = 10 rpm),
As described in the "dynamic method" of this embodiment, the whisker R _b
Extension and core R_aExpansion of diameter is almost stopped
The core R_aOnly the amount of photoresist solution
The expanded momentum is increased (FIGS. 7 and 8). That
Acceleration period (t_E~ T₁₁) In the present embodiment,
The action already described in "Dynamic method"
It occurs in dysto, and mustache R_bAnd new mustache R_b'Departure
With the addition of raw materials, the time required for coating is greatly reduced. Well
Also, the solvent has been applied in advance to reduce the contact angle.
Then, in each of the above processes, core R_aThe diameter of the
It will be done more quickly than the_bAnd new
Beard R_b‘
The width will be greatly expanded in the circumferential direction.

After the acceleration period elapses, t₁₃Time point
Reaches a rotation speed R8 (corresponding to the sixth rotation speed of the present invention)
Like t₁₂At that point, deceleration is started, and the rotation speed R8
T ₁₄The entire surface of the substrate W can be maintained by maintaining
A slight surplus of the photoresist liquid R covering the
Shake off to form photoresist film of desired thickness.
Note that t₁₃From time t₁₄Up to the time point, the process (f) of the present invention
Equivalent to. As mentioned above, the coating time is shortened.
Beard R_b(And the new mustache R_b’)
It is possible to reduce the amount of photoresist liquid that is scattered by
The amount of photoresist solution required to form a thick film
It can be extremely small.

The rotation speed switching start time T _a ', the rotation speed switching time T _b , and the deceleration start time T _c may be set in consideration of various conditions as described in the "dynamic method" of this embodiment. Good.

Further, the supply time T of the photoresist solution
_In addition to what is shown in FIG. 15, _SU is the deceleration period (t _{10 to} t _E ) as indicated by the dotted arrow and the supply time (T _SU ).
It is the same as in the above-described embodiment that the setting may be made over.

In the above description, "0" rpm and "100" rpm are taken as examples of the rotational speeds when decelerated, but the rotational speeds are lower than the third rotational speed R5. Various rotation speeds can be selected as long as the rotation speed can temporarily reduce the expansion of the core _{Ra and} the extension of the beard _Rb .

In the first and second embodiments,
Although the photoresist liquid has been described as an example of the coating liquid, the method of the present invention can be applied to a coating liquid such as an SOG liquid or a polyimide resin.

[0101]

As is apparent from the above description, according to the invention described in claim 1, before the coating liquid supplied to the surface of the substrate spreads at the third rotation speed and covers the entire surface of the substrate. In addition, by increasing the rotation speed of the substrate to the fourth rotation speed, an inertial force can be applied to the flow of the coating solution radially extended from the concentric coating solution, and the flow of each radial coating solution can be increased. The gap between them can be narrowed rapidly. Also,
Since the solvent is applied to the surface of the substrate prior to the application of the coating solution, the flow of the coating solution extending from the coating solution can be made thin and large, and the expansion of the diameter of the concentric coating solution can be accelerated. At the same time, when an inertial force is applied to the flow of the coating liquid, it can be easily bent largely in the circumferential direction.

Therefore, the time required for the coating liquid to cover the entire surface of the substrate can be shortened. As a result, the amount of the coating liquid scattered around the substrate through the radial flow of the coating liquid can be reduced, and the amount of the coating liquid required to form the coating film having a desired film thickness can be reduced. This makes it possible to reduce the amount of the expensive coating liquid as compared with the developing liquid and the rinse liquid, so that the manufacturing cost of the semiconductor device and the like can be reduced and the throughput can be improved.

According to the invention described in claim 2, the coating liquid coating method by the so-called "dynamic method", in which the coating liquid is supplied while the substrate is rotated and the supply is completed in that state, The same effect as that described in claim 1 can be obtained.

According to the third aspect of the invention, the coating liquid is supplied by the so-called "static method" in which the supply of the coating liquid is started while the substrate is stationary and the supply of the coating liquid is completed in that state. Even with the coating method, the same effect as that of the first aspect can be obtained.

According to the fourth aspect of the present invention, the supply of the coating liquid is started in the state where the substrate is stationary, and the supply of the coating liquid is started after the number of rotations of the substrate is increased to the third number of rotations. The effect described in claim 1 can be obtained even by a coating liquid coating method (stamic method) in which the above static method and stamic method are combined.

According to the fifth aspect of the present invention, the rotation speed of the substrate is set to the third rotation speed before the coating liquid supplied to the front surface of the substrate spreads by the third rotation speed to cover the entire surface of the substrate.
The speed is temporarily reduced to the fourth speed, which is lower than
By continuing to supply the coating liquid during this time, it is possible to increase only the concentric coating liquid and increase the expanding momentum. After that, the fifth speed higher than the fourth speed
By increasing the number of revolutions of the substrate to the number of revolutions of, a new flow of the coating liquid can be generated between the flow of the coating liquid radially extending from the concentric coating liquid and each coating An inertial force can be applied to the liquid flow, and the gap between each radial coating liquid flow can be rapidly narrowed. In addition, since the solvent is applied to the surface of the substrate prior to the application of the coating liquid, the flow of the coating liquid extending from the coating liquid can be made thin and large, and the expansion of the diameter of the concentric coating liquid can be accelerated. In addition, when an inertial force is applied to the flow of the coating liquid and a new flow of the coating liquid, it can be easily bent largely in the circumferential direction.

Therefore, the time required for the coating liquid to cover the entire surface of the substrate can be shortened. As a result, the amount of the coating liquid scattered around the substrate through the radial flow of the coating liquid can be extremely reduced, and the amount of the coating liquid required to form the coating film having a desired film thickness can be reduced. . This makes it possible to reduce the amount of the expensive coating liquid as compared with the developing liquid and the rinse liquid, so that the manufacturing cost of the semiconductor device and the like can be reduced and the throughput can be improved.

According to the sixth aspect of the present invention, the coating liquid coating method may be a so-called "dynamic method" in which the coating liquid is supplied while the substrate is rotated and the supply is completed in that state. The same effect as the effect described in claim 5 can be obtained. Further, since it is possible to increase the rotation speed of the substrate to the fifth rotation speed while maximizing the expansion momentum of the concentric coating liquid, the diameter of the concentric coating liquid can be expanded faster and It is possible to efficiently generate a new flow of the coating liquid between the radial flows of the coating liquid. Therefore, the gap between the radial flows of the coating liquid can be narrowed more quickly, and the time until the coating liquid covers the entire surface of the substrate can be further shortened.

According to the invention described in claim 7, the supply of the coating liquid is started in a state where the substrate is stationary, and the supply is completed when the substrate is started to rotate. The same effect as in claim 5 can be obtained even by a coating liquid coating method (stamic method) in which the above methods are combined.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a rotary substrate coating apparatus to which the method of the present invention is applied.

FIG. 2 is a time chart showing a photoresist liquid coating method (dynamic method) according to the first embodiment.

FIG. 3 is a diagram which is used for explaining a photoresist liquid coating method.

FIG. 4 is a schematic diagram showing the behavior of a photoresist solution.

FIG. 5 is another embodiment (static method and stamic method) of the photoresist liquid coating method according to the first embodiment.
2 is a time chart showing.

FIG. 6 is a time chart showing a photoresist liquid coating method (dynamic method) according to the second embodiment.

FIG. 7 is a schematic side view showing the behavior of a photoresist solution.

FIG. 8 is a schematic side view showing the behavior of a photoresist solution.

FIG. 9 is a schematic plan view showing the behavior of a photoresist solution.

FIG. 10 is a schematic plan view showing the behavior of a photoresist solution.

FIG. 11 is a schematic plan view showing the behavior of a photoresist solution.

FIG. 12 is a schematic plan view showing the behavior of a photoresist solution.

FIG. 13 is a schematic plan view showing the behavior of the photoresist liquid.

FIG. 14 is a schematic plan view showing the behavior of a photoresist solution.

FIG. 15 is a time chart showing another embodiment (stamic method) of the photoresist liquid coating method according to the second embodiment.

FIG. 16 is a diagram showing a main part of a rotary substrate coating apparatus according to a conventional example.

FIG. 17 is a time chart showing a coating liquid coating method according to a conventional example.

FIG. 18 is a diagram for explaining a coating liquid coating method according to a conventional example.

[Explanation of symbols]

10 ... Suction spin chuck 13 ... Scatter prevention cup 30 ... Coating liquid discharge nozzle 31 ... Coating liquid supply part 32 ... Drive part 40 ... Solvent discharge nozzle 41 ... Solvent supply part 42 ... Drive part 50 ... Control part 51 ... Memory W ... Substrate R ... Photoresist liquid (coating liquid) _Ra ... Core (circular coating liquid) _Rb ... Mustache _Rb '... New mustache _Rc ... Scattered photoresist liquid _Rd ... Excess photoresist liquid

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunobu Matsunaga 322 Hazushishi Furukawacho, Fushimi-ku, Kyoto, Kyoto Prefecture Dainippon Screen Mfg. Co., Ltd. Rakusai Works (56) Reference JP-A-6-326014 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/02 B05D 1/40 H01L 21/027 H01L 21/68 G06F 17/50

Claims (7)

(57) [Claims] 1. A method for applying a coating solution, which comprises applying a coating solution onto a surface of a substrate to form a coating film having a desired film thickness, comprising: (a) leaving the substrate stationary or supplying a solvent.
While rotating at the first rotation speed of the order, the steps for supplying a solvent to the vicinity of the surface center of the substrate, the substrate in the second rotational speed to diffuse (b) solvent
A step of rotating the substrate to diffuse the solvent supplied to the surface of the substrate over the entire surface, and (c) a state in which the substrate is stationary or a coating liquid is supplied.
In the state of being rotated at the third rotation speed for the purpose of, the step of supplying the coating solution to the vicinity of the center of the surface, and (d) Before covering the entire surface of the substrate by increasing the rotation speed of the substrate to a fourth rotation speed higher than the third rotation speed , and (e) changing the rotation speed of the substrate to a film thickness. Fifth for adjusting
And a step of adjusting the film thickness of the coating film covering the entire surface of the substrate while maintaining the rotation speed for a predetermined time, and performing the steps in that order. 2. The coating liquid coating method according to claim 1, wherein the coating liquid supplied in the step (c) is started in a state where the substrate is rotated at a third rotation speed, and in that state. A method for applying a coating liquid, characterized in that the supply is completed. 3. The coating liquid coating method according to claim 1, wherein the coating liquid supplied in the step (c) is started in a state where the substrate is stationary and is completed in that state. A method for applying a coating liquid, comprising: 4. The coating liquid coating method according to claim 1, wherein the coating liquid supplied in the step (c) is started while the substrate is stationary, and the rotation speed of the substrate is set to a third value. A method for applying a coating liquid, characterized in that the supply is completed after the rotation speed is started to increase. 5. A coating solution coating method for forming a coating film having a desired film thickness by supplying a coating solution onto the surface of a substrate, comprising: (a) leaving the substrate stationary or supplying a solvent.
While rotating at the first rotation speed of the order, the steps for supplying a solvent to the vicinity of the surface center of the substrate, the substrate in the second rotational speed to diffuse (b) solvent
A step of rotating the substrate to diffuse the solvent supplied to the surface of the substrate over the entire surface, and (c) a state in which the substrate is stationary or a coating liquid is supplied.
In the state of being rotated at the third rotation speed for the purpose of, the step of supplying the coating solution to the vicinity of the center of the surface, and (d) Before the entire surface of the substrate is covered with the substrate, the process of reducing the rotation speed of the substrate to a fourth rotation speed lower than the third rotation speed; and (e) the coating supplied in the step (c). before the liquid is spread over the entire surface of the substrate, wherein the rotational speed of the substrate
A process of increasing the rotation speed to a fifth rotation speed higher than the fourth rotation speed ; and (f) a sixth rotation speed for adjusting the film thickness of the substrate.
And the process of adjusting the film thickness of the coating film covering the entire surface of the substrate is performed in that order, and the coating liquid is continuously supplied at least during the process (d). A method for applying a coating liquid, comprising: 6. The coating liquid coating method according to claim 5, wherein the coating liquid supplied in the step (c) is started while the substrate is rotated at a third rotation speed, and the step (c) is started. The coating liquid coating method is characterized in that the supply is completed when the number of rotations of the substrate is increased to the fifth number of rotations in step e). 7. The coating liquid coating method according to claim 5, wherein the coating liquid supplied in the step (c) is started to be supplied while the substrate is stationary, and the coating liquid is applied to the substrate in the step (e). A method for applying a coating liquid, characterized in that the supply is completed when the number of rotations starts to increase to a fifth number of rotations.