JP2002270495A - Substrate treating method and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate treating method and an apparatus therefor, Which levels a coating liquid by a travelling wave to form a coat film without giving stress to a substrate. SOLUTION: The substrate treating method for forming a film of a coating liquid R on the surface of a substrate S comprises a step for expanding and leveling a coating liquid R fed to the substrate S surface by a travelling wave PW to form a film. The generated travelling wave PW moves and expands the coating liquid R fed to the substrate S surface in its direction, thereby leveling the liquid R. Thus, a coat film can be formed without giving stress to the substrate S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supplying a coating liquid such as a photoresist liquid to a circular semiconductor wafer or a rectangular glass substrate (hereinafter simply referred to as a substrate) to form a coating film on the surface of the substrate. The present invention relates to a substrate processing method and an apparatus therefor.

[0002]

2. Description of the Related Art As a conventional method of this kind, a spin coating method is the most representative.

In this method, for example, after a certain amount of coating liquid is supplied while the substrate is rotated at a low speed, the coating liquid is spread over the entire surface of the substrate by rotating the substrate at a high speed. In this case, leveling is performed in such a manner that the coating liquid is shaken off around the periphery to make the film thickness uniform. As a result, a coating film having a substantially constant thickness is formed on the surface of the substrate.

[0004]

However, in the case of such a conventional example, there are the following problems. That is, in order to generate a centrifugal force required for leveling, it is necessary to rotate the substrate at a high speed of several thousand RPM, which causes a problem that a large stress is applied to the substrate.

The present invention has been made in view of such circumstances, and a substrate processing method capable of forming a coating film without applying stress to a substrate by leveling a coating solution with a traveling wave. And an apparatus therefor.

[0006]

The present invention has the following configuration in order to achieve the above object. That is, in the method of the present invention, in a substrate processing method for forming a coating film of a coating liquid on a surface of a substrate, a coating film is formed by spreading and leveling the coating liquid supplied to the surface of the substrate by a traveling wave. It is characterized by doing.

According to a second aspect of the present invention, in the substrate processing method of the first aspect, the supply and leveling of the coating liquid are performed in an atmosphere pressurized to a pressure higher than the saturated vapor pressure of the coating liquid. It is characterized by that.

According to a third aspect of the present invention, in the substrate processing method of the first or second aspect, the supply and leveling of the coating liquid are performed in the same atmosphere as the solvent contained in the coating liquid. It is characterized by the following.

According to a fourth aspect of the present invention, there is provided a substrate processing apparatus for forming a coating film of a coating liquid on a surface of a substrate, wherein the holding means holds the substrate in a substantially horizontal posture, and the coating liquid is supplied to the substrate. A supplying means, and a traveling wave generating means for generating a traveling wave on the substrate, wherein the traveling liquid is generated by the traveling wave generating means, so that the coating liquid supplied from the supplying means to the surface of the substrate is exposed to the surface of the substrate. The film is formed by spreading and leveling.

According to a fifth aspect of the present invention, in the substrate processing apparatus of the fourth aspect, an outer container for accommodating the holding means, and the pressure in the outer container is set to be higher than the saturated vapor pressure of the coating liquid. And a solvent vapor pressurizing means for pressurizing.

[0011]

According to the first aspect of the present invention, when a traveling wave is generated, the coating liquid supplied to the surface of the substrate is moved and spread in the direction, and the coating liquid has a uniform thickness. Leveled.

According to the second aspect of the present invention, volatilization of the solvent contained in the coating liquid can be suppressed by pressurizing the atmosphere to a pressure higher than the saturated vapor pressure of the coating liquid.

[0013] According to the third aspect of the present invention, the solvent contained in the coating solution can be prevented from volatilizing by the solvent atmosphere of the coating solution.

According to the fourth aspect of the present invention, when the coating liquid is supplied from the supply means to the substrate held by the holding means and the traveling wave is generated by the traveling wave generating means, the coating liquid is The liquid is moved in the direction and spread, and the coating liquid is leveled.

[0015] According to the apparatus described in claim 5, the inside of the outer container is pressurized to a saturated vapor pressure or higher by the solvent vapor pressurizing means, whereby the solvent volatilization of the coating liquid can be suppressed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. <Substrate Processing Method> FIG. 1 is a schematic diagram for explaining an embodiment of a substrate processing method according to the present invention, and is a schematic diagram in which a part of a substrate supplied with a coating liquid is enlarged.

First, the coating liquid R is supplied to the entire surface of the substrate S (FIG. 1A). The method of supplying the coating liquid R is not particularly limited, but a nozzle method for discharging the coating liquid from a general nozzle in a coating apparatus, an ink jet method for ejecting the coating liquid from a head provided at a distance, a screen used in printing, and the like. For example, a screen system for supplying a coating liquid via a liquid crystal panel can be adopted. The surface of the coating liquid R immediately after being supplied has minute irregularities as shown in the figure.

Next, a surface acoustic wave S is applied to the substrate S and the coating liquid R.
AW is generated, and the traveling wave PW is caused to travel in the horizontal direction (FIG. 1B).

When the traveling wave PW is generated on the substrate S in this manner, the entire coating liquid R is shaken while the entire traveling wave PW is generated.
As a result, the unevenness on the surface of the coating liquid R is smoothed out.

The traveling wave P of the surface acoustic wave SAW for a predetermined time
When the application of W is continued, the coating liquid R is leveled so as to have a uniform thickness (FIG. 1C).

When the leveling is completed as described above, the application of the traveling wave PW is stopped, and then the solvent is volatilized from the coating solution R, thereby forming a coating film on the entire surface of the substrate S.

It is preferable that the time required for leveling is determined by conducting an experiment in advance and obtaining a desired film thickness and taking into consideration uniformity and the like.

When the traveling wave PW is generated as described above, the coating liquid R supplied to the surface of the substrate S is moved in the direction and spreads, and the coating liquid R is leveled. Therefore, a coating film can be formed without giving stress to the substrate S.

It is preferable that the treatment is performed in an atmosphere pressurized above the saturated vapor pressure of the coating liquid R until the leveling is completed after the supply of the coating liquid R. Thus, the volatilization of the solvent contained in the coating liquid R can be suppressed, so that the viscosity of the coating liquid R can be kept substantially constant, and the leveling of the coating liquid R can be facilitated.

The supply and leveling of the coating liquid R are preferably performed in an atmosphere of a solvent contained in the coating liquid R. In this way, the volatilization of the solvent contained in the coating liquid R can be suppressed, so that an atmosphere in which the viscosity of the coating liquid R can be maintained substantially constant can be relatively easily formed, and the leveling of the coating liquid R can be easily performed. You can.

Further, the treatment may be performed in an atmosphere which is higher than the saturated vapor pressure of the coating liquid R and which is filled with a solvent contained in the coating liquid R.

It is not necessary to supply the coating liquid R over the entire surface of the substrate S. That is, the substrate W
The coating liquid R may be supplied to only a part of the substrate S, and the leveling may be performed while spreading the coating liquid R over the entire surface of the substrate S by the subsequently applied traveling wave PW.

<Substrate Processing Apparatus> Next, with reference to FIGS. 2 and 3, an embodiment of a substrate processing apparatus capable of suitably executing the above-described substrate processing method will be described. In addition, FIG.
FIG. 3 is a longitudinal sectional view showing one embodiment of the substrate processing apparatus, and FIG.
2 is a perspective view of the processing table 1. FIG.

The processing table 1 includes a mounting table 3 and a base 5. The mounting table 3 mounts a rectangular substrate S on a mounting surface on the upper surface, and has a plurality of suction holes 3a formed in the mounting surface. A suction passage 3b is connected to each suction hole 3a, and is connected to suction means (not shown). Therefore, by operating the suction means, the substrate S mounted on the mounting table 3 is sucked and the substrate S is held.

The mounting table 3 corresponds to the holding means in the present invention.

The base 5 is provided below the mounting table 3. A plurality of piezoelectric elements 7 are buried in the upper part, and are mounted so that the upper parts thereof are in contact with the lower surface of the mounting table 3.

As the piezoelectric element 7, for example, PZT (Pb
Zr _1-x Ti _x ), but BaTiO ₃ or the like can also be used. Although not shown, the mounting table 3 and the base 5 are connected to each other by a tension coil spring that expands and contracts in the vertical direction. Therefore, the micro vibration (for example, about several μm) of the piezoelectric element 7 is efficiently transmitted, and the mounting table 3 is configured not to cause a positional shift due to the vibration. Wirings 9 for applying signals to be described later are connected to the lower portions of the respective piezoelectric elements 7.

Incidentally, the piezoelectric element 7 corresponds to the traveling wave generating means in the present invention.

The processing table 1 configured as described above
It is covered with an outer container 11 for maintaining a constant processing atmosphere. The outer container 11 includes a shutter (not shown) that opens and closes when the substrate S is loaded and unloaded, and an inkjet nozzle 13 that is an inkjet type nozzle is provided above the shutter.

The ink jet nozzle 13 is screwed to a screw shaft 15 linked to a motor (not shown), and is horizontally movable along the screw shaft 15 in the left-right direction in the figure. It is preferable that the internal pressure of the ink jet nozzle 13 is set to be higher than the internal pressure of the outer container 11 to prevent the atmosphere of the outer container 11 from flowing into the nozzle 13. Discharge unit 13a of inkjet nozzle 13
Although the substrate and the surface of the substrate S are separated from each other, the application liquid to which pressure is applied is discharged from the discharge surface 13a, and the coating liquid in the form of fine droplets adheres to the surface of the substrate S.

Incidentally, the ink jet nozzle 13 corresponds to the supply means in the present invention.

The outer container 11 is connected to a solvent vapor supply source 17 corresponding to the solvent vapor pressurizing means of the present invention and a dry N ₂ supply source 19. The solvent vapor supply source 17
The vapor of the solvent contained in the coating liquid discharged from the inkjet nozzle 13 is supplied to the outer container 11. In addition to the function of simply supplying steam, the function of pressurizing the atmosphere of the outer container 11 to be higher than the saturated vapor pressure of the coating liquid is also provided.

The dry N ₂ supply source 19 positively brings the inside of the outer container 11 into a dry atmosphere. Thus, the coating liquid applied to the substrate S and leveled is dried to form a coating film on the surface of the substrate S.

The wiring 9 connecting the plurality of piezoelectric elements 7 described above
Is connected to the signal providing unit 21. The signal providing unit 21 includes a signal generating unit 23, a bias adjusting unit 25,
And a switching circuit 27.

The signal generator 23 outputs a signal having a frequency f ₁ corresponding to the natural frequency of the piezoelectric element 7 based on an instruction from the controller 29, for example. Frequency f ₁ is, for example, 700
It is about 1,000 MHz.

The bias adjusting unit 25 controls the signal generating unit 23
The amount of bias to be applied is determined based on an instruction from the control unit 29.
Wave number f_Two To change. This frequency f_Two Is, for example,
Number f ₁ About 1/10, specifically 70 to 100
Hz.

The switching circuit 27 includes a signal generator 23.
In order to apply the output from the control unit 29 to any one of the plurality of piezoelectric elements 7, the output destination is electrically switched in a predetermined order according to the instruction of the control unit 29.

Each piezoelectric element 7 of the base 5 has a peripheral
Wave number f₁ Resonates with the signal of the above to generate minute vibration. This
When the mounting table 3 is waved up and down by the minute vibration of
Surface acoustic waves occur due to sexual deformation. Also, the frequency f₁ No faith
The signal corresponds to the frequency f in FIG. _Two Is synthesized with the signal of
And each piezoelectric element 7 has a frequency f₁ Micro vibration by the signal of
While frequency f_Two Small vibration in the vertical direction by the signal of
Is being changed. Further, the switching circuit 2
7, the surface acoustic waves generated on the mounting table 3 are constant.
Traveling wave traveling in the direction of.

In order to efficiently use the traveling wave so as not to attenuate the traveling wave, it is preferable to set the arrangement intervals of the piezoelectric elements 7 as shown in FIG.

That is, the arrangement interval L is set to １ ／ of the wavelength at which the substrate S resonates. For example, when the frequency f ₁ is 38 kHz and the substrate S is a glass substrate, if the speed of the acoustic wave in the glass is 5000 m / sec, the wavelength λ = about 13 cm, so the arrangement interval L = about 3c
m.

Next, processing of a substrate using the above-configured substrate processing apparatus will be described.

First, the substrate S is mounted on the mounting table 3 using a substrate transport mechanism (not shown). Then, the control unit 29 controls the solvent vapor supply source 17 to supply the solvent vapor into the outer container 11 and maintain the inside of the outer container 11 at a pressure equal to or higher than the saturated vapor pressure of the application liquid.

The suction means (not shown) is operated so that the back surface of the substrate S is sucked by the suction holes 3 a so that the substrate S does not shift from the mounting table 3. In the longitudinal direction. As a result, the coating liquid R is supplied thickly over the entire surface of the substrate S, but as described above, the surface includes irregularities (FIG. 1A).

After the application liquid R is applied to the entire surface of the substrate S, the signal applying section 21 is operated for a predetermined time to generate a traveling wave traveling in the horizontal direction on the substrate S for a predetermined time. Thereby, the coating liquid R on the substrate S is moved and spread, and is leveled to a constant film thickness (FIG. 1).
(B), (c)).

When the leveling is completed, the solvent vapor supply source 17 is stopped, and a dry nitrogen gas is supplied from the dry N ₂ supply source 19 into the outer container 11. Thus, the solvent can be volatilized from the leveled coating liquid to form a coating film.

After the solvent vapor supply source 17 is stopped without introducing nitrogen gas into the outer container 11, a traveling wave whose frequency and amplitude are devised is generated from the signal generating section 23, and thereby the solvent is supplied. May be moved to perform the drying process.

Thereafter, it is preferable that the substrate S is transported to a separate baking furnace to perform a baking process to enhance the adhesion between the substrate S and the coating film.

When the traveling wave is generated as described above, the substrate S
The coating liquid supplied to the surface of the substrate S is spread in that direction, and the coating liquid is leveled, so that a coating film can be formed without applying stress to the substrate S. Further, by setting the inside of the outer container 11 to a pressurized atmosphere that is equal to or higher than the saturated vapor pressure of the coating liquid, volatilization of the solvent contained in the coating liquid can be suppressed.
The viscosity of the coating liquid can be kept almost constant, and the leveling of the coating liquid can be easily performed. At the same time, by setting the inside of the outer container 11 to the solvent atmosphere of the coating liquid, the volatilization of the solvent contained in the coating liquid can be suppressed, and the atmosphere in which the viscosity of the coating liquid can be kept almost constant can be formed relatively easily. While it is possible, the leveling of the coating solution can be facilitated.

In the above configuration, the ink jet nozzle 13 is provided, but the same effect can be obtained by an apparatus having a normal nozzle or a slit nozzle used in spin coating instead. It is possible.
Alternatively, the leveling may be performed by the above-described method after the application liquid is spread over the entire surface of the substrate by low-speed spin coating.

Instead of applying the coating liquid to the entire surface of the substrate S as described above and then leveling with a traveling wave, the coating liquid is applied to one end of the substrate S as shown in FIG. Alternatively, as shown in FIG. 5 (b), it may be moved by a traveling wave to spread the coating liquid over the entire surface of the substrate S and to perform leveling.

Further, in the above configuration, a plurality of piezoelectric elements 7 are arranged relatively densely to generate traveling waves, but the piezoelectric elements 7 are provided only at both ends of the base 5 and A traveling wave may be generated on the mounting table 3 and the substrate S for vibration and vibration absorption.

As the piezoelectric element 7, it is preferable to use a Langevin vibrator that can efficiently vibrate using resonance.

The formation of the pressurized atmosphere and the vapor atmosphere by the solvent vapor supply source 17 is not essential. Depending on the type of the coating liquid, it is not necessary to form these atmospheres, and the structure of the solvent vapor supply source 17 is unnecessary. It is.

[0059]

As is apparent from the above description, according to the method of the first aspect, when a traveling wave is generated,
The coating liquid supplied to the surface of the substrate is moved in the direction and spread, and the coating liquid is leveled. Therefore, a coating film can be formed without applying stress to the substrate.

According to the second aspect of the present invention, the volatilization of the solvent contained in the coating solution can be suppressed by the pressurized atmosphere having a saturated vapor pressure or higher. Therefore, since the viscosity of the coating liquid can be kept substantially constant, leveling of the coating liquid can be easily performed.

According to the third aspect of the present invention, the volatilization of the solvent contained in the coating liquid can be suppressed by the solvent atmosphere of the coating liquid. Therefore, an atmosphere in which the viscosity of the coating liquid can be maintained substantially constant can be relatively easily formed, and leveling of the coating liquid can be easily performed.

Further, according to the apparatus invention described in claim 4, the method invention described in claim 1 can be suitably implemented.

According to the apparatus described in claim 5, the method described in claim 2 can be suitably implemented.

[Brief description of the drawings]

FIGS. 1A to 1C are schematic diagrams in which a substrate to which a coating liquid is supplied is partially enlarged.

FIG. 2 is a longitudinal sectional view showing one embodiment of the substrate processing apparatus.

FIG. 3 is a perspective view of a processing table.

FIGS. 4A and 4B are diagrams illustrating profiles of signals output from a signal providing unit.

FIGS. 5A and 5B are diagrams illustrating another example of a supply form of a coating liquid.

[Explanation of symbols]

 S: substrate R: coating liquid SAW: surface acoustic wave PW: traveling wave 1: processing table 3: mounting table (supporting means) 3a: suction hole (adsorption means) 5: base 7: piezoelectric element (traveling wave generating means) 13 ... Inkjet nozzle (supplying means) 21 ... Signal application unit 29 ... Control unit

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H025 AA00 AA18 AB13 AB14 AB15 AB16 AB17 EA04 4D075 BB12Z BB56Z BB69Z CA48 DA06 DB13 DB14 DC22 DC24 EA45 4F042 AA02 AA07 AA10 DC03 DD02 DD41 5F046 JA02 JA09 JA16 JA27

Claims (5)

[Claims] 1. A substrate processing method for forming a coating of a coating liquid on a surface of a substrate, wherein the coating is formed by spreading and leveling the coating liquid supplied to the surface of the substrate by a traveling wave. Processing method. 2. The substrate processing method according to claim 1, wherein the supply and the leveling of the coating liquid are performed in an atmosphere pressurized to a saturation vapor pressure of the coating liquid or higher. 3. The substrate processing method according to claim 1, wherein the supply and the leveling of the coating liquid are performed in the same atmosphere as the solvent contained in the coating liquid. 4. A substrate processing apparatus for forming a coating film of a coating liquid on a surface of a substrate, comprising: holding means for holding the substrate in a substantially horizontal posture; supply means for supplying the coating liquid to the substrate; Forming a coating by spreading the coating liquid supplied from the supply unit to the surface of the substrate and leveling the coating liquid by generating the traveling wave by the traveling wave generating unit. A substrate processing apparatus. 5. The substrate processing apparatus according to claim 4, further comprising: an outer container accommodating the holding unit; and a solvent vapor pressurizing unit configured to pressurize the inside of the outer container to a pressure equal to or higher than a saturated vapor pressure of the application liquid. A substrate processing apparatus.