JPH1022220A - Method and device for applying coating liquid to substrate and applicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the embedding property of coating liquid to the fine recessed part of a pattern formed on a substrate surface by turning a substrate at a low speed or stopping and holding it for a predetermined time after a coating liquid is applied to the surface of the substrate while rotating the substrate at a high speed and the entire surface there is covered with the coating liquid. SOLUTION: A substrate W is rotated at a high speed, for example, at 2,000 to 4,000rpm. Then an SOG material is discharged to the surface of the substrate W through a discharging nozzle 18 by operating a piezoelectric pump while the substrate W is rotated at a high speed. The substrate W is kept rotating for a few seconds after the SOG material is discharged, and when the surface of the substrate W is entirely covered with the SOG material, the rotating of the substrate is stopped, or its rotating speed is changed to low speed. Then, the substrate W is kept being stopped or rotated at a low speed for about 5 seconds, for example. During such a period, the SOG material is embedded to the fine recess of a pattern formed on the surface of the substrate W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor wafer,
SOG (Spin on) is applied to the surface of a substrate such as a glass substrate plate for a liquid crystal display (LCD) or a photomask.
glass) material, a dopant material, a method of applying a coating liquid to a substrate on which a coating liquid such as a photoresist liquid is coated, and
The present invention relates to an apparatus for applying a coating liquid to a substrate used for performing the method.

[0002]

2. Description of the Related Art A coating liquid is applied to the surface of a substrate such as a semiconductor wafer.
For example, as a method for applying the SOG material, there are two methods called a static application method and a dynamic application method, respectively. In the former static coating method, the coating liquid is discharged onto the surface of the substrate while the substrate is stopped, and the substrate is rotated at a low speed to spread the coating liquid over the entire surface of the substrate, and then spin-dried using high-speed rotation. Is the way. In the latter dynamic coating method, the coating liquid is discharged onto the surface of the substrate while rotating the substrate, the coating liquid spreads over the entire surface of the substrate, and the substrate surface is completely covered with the coating liquid. This is a method of spin-drying by rotating.

[0003]

However, each of the static coating method and the dynamic coating method has advantages and disadvantages. That is, in the static coating method, the coating liquid is discharged onto the surface of the substrate while the substrate is stopped, the substrate is rotated at a low speed to spread the coating liquid over the entire surface of the substrate, and then spin-dried using high-speed rotation. Therefore, the coating liquid discharged onto the substrate surface spreads relatively slowly over the entire surface of the substrate. Therefore, the coating liquid can be easily embedded in the fine concave portions of the pattern formed on the surface of the substrate, but it is necessary to discharge the coating liquid in such an amount that the coating liquid spreads over the entire surface of the substrate in a stopped state and at a low speed. Therefore, there is a problem that the amount of the coating liquid used increases, and in particular, when the viscosity of the coating liquid increases, the amount used increases.

On the other hand, in the dynamic coating method, the coating liquid is discharged onto the surface of the substrate while rotating the substrate, so that the coating liquid discharged onto the surface of the substrate spreads quickly over the entire surface of the substrate. For this reason, the amount of the coating liquid used may be small, but the amount of the coating liquid entering the fine concave portions of the pattern formed on the surface of the substrate is reduced, and the coating liquid once entering the fine concave portions also Since a part of the pattern is swung out of the fine concave portion with the rotation of the substrate, there is a problem that the embedding property of the coating liquid into the fine concave portion of the pattern is poor.

The present invention has been made in view of the above circumstances, and has a good embedding property of a coating liquid into fine concave portions of a pattern formed on a surface of a substrate, and a method of using the coating liquid. It is an object of the present invention to provide a method of applying a coating liquid to a substrate, which requires a small amount of liquid, and to provide an apparatus for applying a coating liquid to a substrate, which can suitably perform such a method.

[0006]

The invention according to claim 1 is
In a coating liquid application method in which a coating liquid is discharged onto the surface of a substrate and the entire surface of the substrate is coated, a step of discharging the coating liquid onto the surface of the substrate while rotating the substrate at a high speed, and applying the entire surface of the substrate. A step of continuing high-speed rotation of the substrate until the substrate is coated with the liquid, and a step of rotating or stopping the substrate at a low speed after the entire surface of the substrate is coated with the coating liquid and maintaining the state for a predetermined time And sequentially goes through.

According to a second aspect of the present invention, there is provided a substrate holding / rotating means for holding a substrate in a horizontal position and rotating it about a vertical axis, and discharging a coating liquid onto the surface of the substrate held by the substrate holding / rotating means. A discharge nozzle to be supplied, a coating liquid supply means for supplying a coating liquid to the discharge nozzle, and a control means for controlling a rotation operation of the substrate holding / rotating means and controlling a coating liquid supply operation of the coating liquid supply means. In the coating liquid coating device provided, the coating liquid supply means is configured to include a piezoelectric pump that sucks the coating liquid stored in the liquid storage tank and sends out the suctioned coating liquid, and the control means Controlling the substrate holding / rotating means and the coating liquid supply means, discharging the coating liquid onto the surface of the substrate while rotating the substrate at a high speed, and until the entire surface of the substrate is covered with the coating liquid, High-speed rotation And the entire surface of the substrate after being coated with the coating solution, characterized in that to hold the substrate by being allowed or stopped rotating at a low speed for a predetermined time that state.

In the coating liquid coating method according to the first aspect of the present invention, the coating liquid is discharged onto the surface of the substrate while rotating the substrate at a high speed. The surface of the substrate spreads over the entire surface of the substrate and is coated with the coating liquid. Therefore, the amount of the coating liquid discharged to the surface of the substrate can be reduced. Then, after the entire surface of the substrate is coated with the coating solution, the substrate is rotated or stopped at a low speed and held in that state for a predetermined time, during which time the fine concave portions of the pattern formed on the surface of the substrate are removed. The coating liquid will enter. Therefore, the embedding property of the coating liquid into the fine concave portions of the pattern is improved.

In the coating liquid coating apparatus according to the second aspect of the present invention, first, the substrate is held in a horizontal posture by the substrate holding / rotating means and rotated at a high speed about a vertical axis. Is applied to the surface of the substrate.
As described above, since the coating liquid is discharged onto the surface of the substrate while rotating the substrate at a high speed, the coating liquid discharged onto the substrate surface quickly spreads over the entire surface of the substrate, and is thus discharged onto the surface of the substrate. Therefore, the amount of the coating liquid to be used is small. The discharge of the coating liquid is performed by sucking the coating liquid stored in the liquid storage tank into the piezoelectric pump and sending out the sucked coating liquid to the discharge nozzle by the piezoelectric pump.

Here, as a coating liquid supply means for supplying the coating liquid to the discharge nozzle, conventionally, as shown in a schematic diagram in FIG. 3, the coating liquid 3 is stored in a closed pressurized container 1. The liquid storage tank 2 is accommodated and nitrogen (N
₂ ) A gas or compressed air is fed to pressurize the liquid surface of the coating liquid 3 in the liquid storage tank 2, and one end of the coating liquid 3 is passed through the liquid supply pipe 4 immersed in the coating liquid 3 in the liquid storage tank 2. In addition, a gas pressure feeding type coating liquid supply device configured to supply a coating liquid to a discharge nozzle 5 connected to a distal end portion of a liquid supply pipe 4 is used. However, in the coating solution supply device of the gas pressure feeding method, the variation of the gas pressure of the nitrogen gas or the compressed air fed into the pressurized container 1 causes the coating solution to be pressure-fed to the discharge nozzle 5 and discharged from the discharge nozzle 5. This causes variations in the amount, and strict reproducibility of the ejection amount cannot be obtained. Therefore, in order to reliably discharge a predetermined amount of the coating liquid onto the surface of the substrate, it is necessary to discharge the coating liquid more than the predetermined amount in consideration of a discharge amount error. As described above, in the case of using the gas-pressure-feeding coating liquid supply device that is conventionally generally used for this kind of application, the coating liquid is discharged onto the surface of the substrate while rotating the substrate at a high speed as described above. As a result, even if an attempt is made to reduce the ejection amount of the application liquid, the effect is reduced. In contrast, claim 2
In the apparatus according to the present invention, the application liquid is supplied to the discharge nozzle using a piezoelectric pump.
By adjusting the voltage value and frequency of the AC voltage applied thereto, a predetermined amount of the coating liquid can be supplied to the discharge nozzle accurately and with good reproducibility even with a small amount of the coating liquid. Therefore, when the application liquid is discharged onto the substrate surface while rotating the substrate at a high speed to reduce the discharge amount of the coating liquid, the effect can be sufficiently obtained.

When the entire surface of the substrate is covered with the coating liquid, the control means controls the substrate holding / rotating means, and the substrate is rotated or stopped at a low speed. In this state, while the substrate is held for a predetermined time, the coating liquid enters the fine concave portions of the pattern formed on the surface of the substrate, so that the embedding property of the coating liquid into the fine concave portions of the pattern is improved.

[0012]

Preferred embodiments of the present invention will be described below with reference to the drawings.

At first, FIG. 2 schematically shows a part in a longitudinal section and another part, and FIG. 2 shows a coating liquid coating apparatus used for performing a coating liquid coating method on a substrate according to the present invention. An example of the configuration will be described. This coating liquid coating apparatus (spin coater) has a spin chuck 10 for holding a substrate W in a horizontal position, and the substrate W held on the spin chuck 10 is connected to a rotating spindle 12 that supports the spin chuck 10. It is rotated about a vertical axis by a spin motor 14. Around the substrate W, there is provided a cup 16 formed in a container shape having an open upper surface and surrounding the side and below the substrate W held by the spin chuck 10. Above the substrate W held by the spin chuck 10, a discharge nozzle 18 for discharging a coating liquid, for example, an SOG material, onto the surface of the substrate W is provided.

The discharge nozzle 18 is connected by a liquid supply pipe 20 to a liquid delivery section 24 of a piezoelectric pump 22.
A liquid suction pipe 28 is provided in the liquid suction section 26 of the piezoelectric pump 22.
The end of the liquid suction pipe 28 is immersed in the SOG material 32 stored in the liquid storage tank 30, and the suction port at the end is arranged near the inner bottom surface of the liquid storage tank 30. I have. The piezoelectric pump 22 has a configuration in which a peripheral portion of a piezoelectric vibrator 36 is fixed to a casing 34, and a pump chamber 38 is formed between an upper surface of the piezoelectric vibrator 36 and an inner surface of the casing 34. The liquid delivery unit 2 communicating with the pump chamber 38
Check valves 40 and 42 for preventing back flow of the SOG material are provided in the liquid suction unit 4 and the liquid suction unit 26, respectively. The piezoelectric vibrator 36 is formed by bonding two piezoelectric films 44 made of, for example, ceramics or a polymer, so as to sandwich a thin-film electrode 46 therebetween, and bonding thin plate electrodes 48 to both surfaces thereof. It has a laminated structure. The thin plate electrodes 46 and 48 are electrically connected to a voltage / frequency adjusting unit 52, and the voltage / frequency adjusting unit 52
4 is connected. Further, the control unit 54 is also connected to the spin motor 14. Instead of the laminated piezoelectric vibrator 36 as in the illustrated example, a single-layer piezoelectric vibrator in which thin-film electrodes are bonded to both surfaces of the piezoelectric film may be used. The surface of the piezoelectric vibrator 36 on the pump chamber 38 side is coated with a fluororesin thin film 50 in order to prevent corrosion by a chemical solution and the like. Further, the casing 34, the liquid suction unit 26, and the liquid delivery unit 24 are provided with pinylidene nifid (PVD) to prevent corrosion by a chemical solution.
F) or polypropylene (PP).

The piezoelectric pump 2 having the above configuration
2 is that the piezoelectric vibrator 36 vibrates up and down as indicated by a two-dot chain line by applying an AC voltage to the thin plate electrodes 46 and 48 of the piezoelectric vibrator 36 from the voltage / frequency adjusting unit 52. The SOG material is sucked from the liquid suction unit 26 into the pump chamber 38, and the sucked SOG material is sent out from the pump chamber 38 through the liquid sending unit 24. That is,
When the piezoelectric vibrator 36 is displaced downward, the check valve 40 of the liquid delivery unit 24 is closed and the check valve 42 of the liquid suction unit 26 is closed.
Is opened, the inside of the pump chamber 38 becomes negative pressure, and the SOG material 32 is sucked from the liquid storage tank 30 through the liquid suction pipe 28 to the liquid suction part 26 and flows into the pump chamber 38 from the liquid suction part 26. I do. On the other hand, when the piezoelectric vibrator 36 is displaced upward,
The check valve 42 of the liquid suction unit 26 is closed and the liquid delivery unit 2 is closed.
The check valve 40 of No. 4 is opened, the inside of the pump chamber 38 becomes positive pressure, and the SOG material sucked into the pump chamber 38 is sent to the liquid supply pipe 20 through the liquid sending section 24. By repeating these operations, the piezoelectric pump 2
2 is supplied to the discharge nozzle 18 through the liquid supply pipe 20 and the SOG material is supplied from the discharge nozzle 18 to the surface of the substrate W.
The material is discharged.

In the piezoelectric pump 22, the piezoelectric vibrator 3
The voltage and frequency of the AC voltage applied to the thin plate-like potentials 46 and 48 of FIG. 6 or both of them are adjusted by the voltage / frequency adjusting unit 52 as necessary. Voltage·
The adjustment of the voltage value and the frequency in the frequency adjustment unit 52 is performed based on a control signal from the control unit 56. When the value or frequency of the AC voltage applied to the thin plate electrodes 46 and 48 of the piezoelectric vibrator 36 changes, the piezoelectric vibrator 3
6 changes, and the supply flow rate and supply pressure of the piezoelectric pump 22 change. The control unit 54 controls the voltage / frequency adjustment unit 52 so that a predetermined amount of the SOG material is discharged from the discharge nozzle 18 to the surface of the substrate W according to the application condition. The setting of the discharge amount of the SOG material according to the application condition is performed by a setting unit or a switch (not shown), and the set value is input to the control unit 54. Further, the control unit 54 sends a control signal to the spin motor 14, and performs control to rotate the substrate W held by the spin chuck 10 at a high speed, at a low speed, or to stop according to a processing program.

Next, the operation of applying the SOG material to the substrate W will be described with reference to the time chart shown in FIG. First, the substrate W is moved at a high speed, for example, 2,000 to 4,000 rpm.
p. m. Rotate with. Then, the SOG material is discharged from the discharge nozzle 18 to the surface of the substrate W by operating the piezoelectric pump 22 while rotating the substrate W at a high speed. For several seconds after the discharge of the SOG material, the high-speed rotation of the
The SOG material spreads over the entire surface of the
When completely covered with the material, the rotation of the substrate W is stopped or the rotation speed of the substrate W is switched to a low speed. And
For a while, for example, for about 5 seconds, the substrate W is stopped or rotated at a low speed. During this time, the SOG material is embedded in the fine concave portions of the pattern formed on the surface of the substrate W. Thereafter, as in the case of the conventional static coating method and dynamic method, for example, the substrate W is kept at 2,000 to 4,000 rpm for about 15 seconds. p. m. After spin-drying by rotating at a high speed, edge cleaning and back-rinsing are performed for about 5 seconds by lowering the rotation speed of the substrate W. Thereafter, the substrate W is again rotated at a high speed and spin-drying is performed for about 10 seconds to dissolve the film. The liquid or the rinsing liquid is scattered and removed from the substrate W.

[0018]

According to the method for applying a coating solution to a substrate according to the first aspect of the present invention, the embedding property of a SOG material or the like into fine concave portions of a pattern formed on the surface of the substrate is good, and the coating quality is kept high. In addition to this, the amount of the coating solution used is small, which is economical.

With the substrate coating liquid coating apparatus according to the second aspect of the present invention, a predetermined amount of coating liquid can be accurately supplied to the surface of the substrate even with a small amount of coating liquid. The above-mentioned effect of the invention according to claim 1, which is economical because the amount of use is small, is ensured, and the embedding property of the coating liquid into the fine concave portions of the pattern formed on the surface of the substrate is excellent. As a result, the coating quality is kept high.

[Brief description of the drawings]

FIG. 1 is a time chart showing an example of an embodiment of a method for applying a coating liquid to a substrate according to the present invention.

FIG. 2 is a view showing an example of a configuration of a coating liquid application apparatus used to carry out a method of applying a coating liquid to a substrate according to the present invention, wherein a part is shown in a longitudinal section and another part is shown. It is a figure which shows each typically.

FIG. 3 is a schematic view of a gas-pressure-feeding coating liquid supply apparatus that is conventionally generally used to supply a coating liquid to a discharge nozzle in a coating liquid coating apparatus for a substrate.

[Explanation of symbols]

 Reference Signs List 10 spin chuck 12 rotation spindle 14 spin motor 18 discharge nozzle 20 liquid supply pipe 22 piezoelectric pump 28 liquid suction pipe 30 liquid storage tank 32 SOG material (coating liquid) 36 piezoelectric vibrator 38 pump chamber 52 voltage / frequency adjusting unit 54 control Part W Substrate

Claims (2)

[Claims] 1. A method for applying a coating liquid to a substrate, wherein the coating liquid is discharged onto the surface of the substrate and the entire surface of the substrate is coated with the coating liquid, wherein the coating liquid is discharged onto the surface of the substrate while rotating the substrate at a high speed. And a step of continuing the high-speed rotation of the substrate until the entire surface of the substrate is coated with the coating liquid; and rotating or stopping the substrate at a low speed after the entire surface of the substrate is coated with the coating liquid. And a step of maintaining the state for a predetermined period of time. 2. A substrate holding / rotating means for holding a substrate in a horizontal posture and rotating about a vertical axis; a discharge nozzle for discharging a coating liquid onto a surface of the substrate held by the substrate holding / rotating means; Coating a substrate with a coating liquid supply unit that supplies a coating liquid to a discharge nozzle, and a control unit that controls a rotation operation of the substrate holding / rotating unit and controls a coating liquid supply operation of the coating liquid supply unit. In the liquid coating apparatus, the coating liquid supply unit includes a piezoelectric pump that sucks a coating liquid stored in a liquid storage tank and sends out the sucked coating liquid, and the control unit controls the substrate holding / rotating unit. And controlling the coating liquid supply means, discharging the coating liquid to the surface of the substrate while rotating the substrate at high speed, until the entire surface of the substrate is coated with the coating liquid, continue the high-speed rotation of the substrate, The entire surface of the substrate is After being coated with the liquid, the coating liquid application device of the substrate low speed is allowed or stop rotating by the substrate, characterized in that to hold a predetermined time that state.