JPH07115051A - Chemical application method and chemical application device - Google Patents

Abstract

PURPOSE:To prevent a hole of a nozzle from being plugged, to improve reproducibility and to enable highly precision chemical application by converting mist applied to a substrate surface from micro-fog to wet mist and by attaching it to a substrate. CONSTITUTION:Chemical 2 such as resist agent is stored in a chemical storage 1. Since viscosity of solvent changes according to temperature and humidity, the chemical storage 1 is stored inside a thermostatic chamber 3. A piping 4 which communicates with the inside of the chemical storage 1 is provided to an outside of the thermostatic chamber 3, and carrier gas C1 containing a large quantity of solvent is supplied from a supply port 4a. A mist generator 7 is a unit for generating micro-fog and changes a small quantity of chemical to mist by using carrier gas C2 containing a large amount of solvent. Furthermore, the mist generator 7 is made to communicate with a secondary tank 10 through a piping 9, and removes mist of a large grain diameter which is supplied form the mist generator 7 in the secondary tank 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical solution coating method and a chemical solution coating apparatus for coating a substrate such as a semiconductor wafer or a liquid crystal panel with a chemical solution such as a resist.

[0002]

2. Description of the Related Art As a conventional technique for applying a chemical solution such as a resist agent onto the surface of a substrate such as a semiconductor wafer or a liquid crystal panel,
Spin coating method and mist method are known.

The spin coating method is a method in which a chemical solution is dropped on the surface of a substrate to rotate the substrate and the centrifugal force is used to form a film having a uniform film thickness on the substrate surface. Poorly, there is a drawback that most of the chemical liquid is scattered and wasted during spinning.

On the other hand, in the mist method, a chemical solution is atomized and applied on the surface of a substrate. Since the chemical solution is atomized in a very small particle size and mass, it can be operated with a small force. In addition, it has an excellent feature that it is relatively easy to diffuse in a large area.

FIG. 4 is a diagram showing a schematic configuration of a conventional chemical liquid coating device using the above-mentioned mist method.

This chemical liquid coating device is provided with a base plate 101.
The coating chamber 102 is fixed on the base plate 101. A nozzle 103 for injecting a chemical liquid mist into the coating chamber 102 is attached to the central portion of the upper wall of the coating chamber 102, and a carrier gas for conveying the chemical liquid mist is provided at both left and right ends of the base plate 101. An exhaust hole 104 is formed to exhaust the excessive chemical solution mist that has not been used for film formation.

Further, inside the coating chamber 102, a table 1 rotated by an external rotation driving device (not shown).
05 is provided, and a flat work (semiconductor substrate) 106 is placed on the table 105.

FIG. 5 is an internal block diagram of the nozzle 103 shown in FIG. 4. The nozzle 103 has an R portion 103A having an enlarged diameter and a plurality of minute nozzle holes 103B formed at the bottom thereof. There is. The chemical solution mist M has a structure in which its cross-sectional area is gradually enlarged at the R portion 103A and is blown out from the nozzle hole 103B at a predetermined flow velocity.

At the time of application, first, the chemical liquid is transported to the nozzle 103 together with the carrier gas in a mist state. The flow velocity is optimized by setting the coating film thickness and the coating time. And a nozzle hole 103B having a small diameter
The chemical solution mist M that has passed through is discharged together with the carrier gas into the coating chamber 102 and is sprayed onto the surface to be coated of the work 106. At this time, the table 105 is rotating at a predetermined rotation speed, and the main coating process is ended by detecting a constant coating time or a film thickness of the work 106.

[0010]

However, the conventional mist method has the following problems.

(1) Since the nozzle hole 103B has a small diameter, when the chemical mist adheres to the nozzle hole 103B, the nozzle hole 103B is clogged and the reproducibility is deteriorated.

(2) After passing through the nozzle 103, the chemical liquid mist M may ride on the carrier gas and be excessively diffused.
In this case, the amount adhered to the surface to be coated is not small and the yield is not only poor, but the chemical solution mist M not adhered to the surface to be coated of the work 106 adheres to the inner wall of the coating chamber 102, and this again causes the apparatus to When operating, it acts as particles (P in FIG. 4) and adheres to the coated surface of a new work 106 to deteriorate the film quality.

(3) Since the chemical mist M has a very small particle size and mass, it has an advantage that it can be operated with a small force, but on the other hand, it is susceptible to disturbance.

Due to the above-mentioned problems, the mist method has a low degree of adoption as compared with the spin coating method, although it has the excellent characteristics described above.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to prevent clogging of nozzle holes to improve reproducibility and also to prevent generation of particles, thereby improving the performance. It is intended to provide a chemical liquid coating method and a chemical liquid coating device that perform accurate chemical liquid coating.

[0016]

In order to achieve the above object, a feature of the first invention is that a chemical solution mist having a particle size of the chemical solution reduced to a micron order is generated, and the chemical solution mist is opposed to a substrate. A nozzle provided is blown toward the surface of the substrate, the chemical mist is brought into contact with the liquid mist between the nozzle and the substrate to generate mixed mist, and the mixed mist is applied to the surface of the substrate. Especially.

A feature of the second invention is that in the first invention, a predetermined potential is applied to the substrate in advance, and a charge having a polarity opposite to that of the predetermined potential is applied to the mixed mist in the vicinity of the nozzle. Is to add.

A feature of the third invention is that in the first invention, the substrate is rotatable and the nozzle is movable, and the coating of the mixed mist onto the substrate surface is performed at least from the nozzle. Of controlling the discharge amount of the chemical liquid, the distance between the nozzle and the substrate, the rotation speed of the substrate, and the moving speed of the nozzle.

A feature of the fourth invention is that in the first invention, the electrode plate is placed at a predetermined distance from the surface of the substrate, and a potential difference is applied in advance between the electrode plate and the substrate. Then, the mixed mist is applied to the surface of the substrate while rotating the substrate.

A feature of the fifth invention is that in the fourth invention, the magnitude of the potential difference applied between the electrode plate and the substrate, the distance between the electrode plate and the substrate surface, and the substrate This is to apply the mixed mist to the substrate surface while controlling the rotation speed.

A sixth aspect of the present invention is characterized in that a chemical liquid mist generator for generating a chemical liquid mist having a particle diameter of the chemical liquid reduced to a micron order, a liquid mist generator for generating a liquid mist, the chemical liquid mist and the liquid mist are provided. It is provided with a nozzle that mixes and sprays a mixed mist, and a table that mounts a substrate at a position facing the nozzle.

A feature of the seventh invention resides in that in the sixth invention, a secondary tank for capturing mist having a large particle size is provided between the chemical liquid mist generator and the nozzle.

A discharge electrode for adding an electric charge to the mixed mist is provided near the nozzle, and a potential difference is applied between the discharge electrode and the substrate.

The eighth invention is characterized in that, in the sixth invention, an electrostatic attractive force generating electrode plate is provided so as to face the substrate, and a potential difference is applied between the electrode plate and the substrate. I have configured it.

[0025]

According to the above-mentioned structure, the first aspect of the invention is to generate a chemical liquid mist (microfog) in which the particle diameter of the chemical liquid is reduced to a micron order and blow it out from the nozzle, and further between the nozzle and the substrate. By bringing the chemical liquid mist into contact with the liquid mist, the mist applied to the surface of the substrate is converted from the micro-fog into wet mist (mixed mist) having a large particle size and attached to the surface of the substrate.

In a second aspect of the present invention, the mixed mist is charged by a method such as discharging, and a high level potential having a polarity opposite to the charged polarity is applied to the substrate, and electrostatic attraction is used. The mixed mist is concentrated and attached to the substrate surface.

In the third to fifth inventions, the film thickness and the uniformity of the film thickness of the coating film formed on the surface of the substrate are controlled according to the degree of demand.

The sixth invention has the same operation as the first invention.

In the seventh aspect of the invention, the chemical mist is converted into microfog by the secondary tank and conveyed to the nozzle.

In the eighth and ninth inventions, the mixed mist is concentrated and adhered to the surface of the substrate.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a chemical liquid coating device according to the first embodiment of the present invention.

In the figure, reference numeral 1 denotes a chemical solution storage device in which a chemical solution 2 such as a resist agent is stored. In the chemical solution 2 such as a resist agent, the evaporation rate of the solvent in the solution changes depending on the temperature and the humidity, so that the characteristics such as the viscosity change greatly. Therefore, the chemical solution storage device 1 is stored in the temperature-controlled room 3. In this example, the chemical storage device 1 was used as a closed container and was further pressurized in a solvent atmosphere.

A pipe 4 communicating with the inside of the chemical solution storage device 1 is provided outside the temperature-controlled room 3, and a carrier gas C1 containing a large amount of solvent is supplied from a supply port 4a of the pipe 4. . Further, the inside of the chemical storage device 1 is provided with a mist generator 7 via a pipe 6 whose temperature is controlled by a temperature control unit 5.
Is in communication with. The mist generator 7 is a unit that generates microfog, and uses a carrier gas C2 containing a large amount of a solvent to mist a small amount of chemical liquid. The carrier gas C2 is supplied to the mist generator 7 from the supply port 8a through the pipe 8.

Further, the mist generator 7 is provided with a pipe 9
The mist supplied from the mist generator 7 having a large inner particle size is removed from the mist generator 7 in the secondary tank 10. As a result, only the mist having a fine particle diameter, which is equal to or smaller than the predetermined particle diameter, slips through the secondary tank 10. Secondary tank 10
Is connected via a pipe 12 to a process container 11 that can measure the amount of resist and can be sealed.
The mist is carried from the supply port 12a by the clean carrier gas C3. The adjustment of the resist amount is performed by adjusting the amounts of the carrier gas C1 from the supply port 4a and the carrier gas C2 from the supply port 8a. The adjustment of the resist amount is optimized in advance using the process container 11.

The secondary tank 10 is connected to the mist dispenser nozzle 22 inside the process chamber 21 via a flexible pipe 23. The mist dispenser nozzle 22 is further connected to a pipe 25 outside the process chamber 21 via a flexible pipe 24, and a solvent mist generator for supplying a mist of solvent (microfog in this embodiment) to the pipe 25. Two
6 are connected. The solvent mist generator 2
The solvent mist from 6 may be a normal mist having a large particle size.

A control rod 27 for moving the mist dispenser nozzle 22 inside the process chamber 21 in the radial direction is fixed. The control rod 2
Reference numeral 7 penetrates the inner wall of the process chamber 21 and is connected to an external moving table 28 so that it can be operated by this moving table 28. The position of the control rod 27 is constantly monitored by the position sensor 29.

In the vicinity of the mist dispenser nozzle 22, a discharge needle 30 supported by a control rod 27 via an insulator is attached. The discharge needle 30 is connected to a high voltage generator 31 installed outside the process chamber 21, and a negative high voltage is applied by the high voltage generator 31. Since the discharge needle 30 is supported by the control rod 27 via the insulator, the mist dispenser nozzle 22 and the discharge needle 3 are provided.
0 has a structure that is movable as a unit in the radial direction of a work to be described later.

A table 32 is provided at a position facing the mist dispenser nozzle 22.
2 is, for example, a plate-shaped work 33 by a vacuum chuck method.
Is fixed. The table 32 has a rotation transmission device 34 outside the process chamber 21, which is connected to a rotation generation device 35.

The control rod 27, the table 32, and the wiring to the discharge needle 30 are all hermetically sealed.

FIG. 2 is a cross-sectional view showing the internal structure of the mist dispenser nozzle 22 in FIG. 1, and a hollow portion inside the nozzle 22 is provided with a pipe 22a for supplying a chemical solution mist in the longitudinal direction. A hollow portion (chamber) 22b outside the pipe 22a is used as a pipe for the solvent mist. The pipe 22a for the chemical liquid mist has a moderately enlarged diameter at an R portion 22c in the middle to facilitate the flow of the mist, and a plurality of minute diameter nozzle holes 22e are provided near the center of the enlarged portion. A perforated straightening plate 22d is provided. The upper side constitutes an upper chamber 22f and the lower side constitutes a lower chamber 22g with the straightening plate 22d as a boundary.

The tip of the pipe 22a for the chemical solution mist is drawn inward from the tip of the nozzle 22. Therefore, between the tip of the pipe 22a and the tip of the nozzle 22. A small amount of space 22h is formed, and the chemical solution mist and the solvent mist are mixed in this space 22h. The outer peripheral portion of the tip of the nozzle 22 has rounded corners 2 for smoothing the flow.
2i is formed, and a mist injection port 22j is formed at the center of the tip of the nozzle 22. The corner 22i is
Although it is round in this embodiment, it may be chamfered only.

Next, a chemical liquid coating method which is carried out by using the chemical liquid coating device configured as described above will be described.

First, the carrier gas C1 is supplied from the supply port 4a.
As a result, clean air is supplied to the chemical liquid storage container 1 together with the solvent vapor. Here, the clean air is used for the work 3
This is because contamination such as particles does not occur on the surface 3 to be coated. By the way, in this embodiment, air that has once been filtered is used.

When the carrier gas C1 is supplied to the drug solution storage container 1, the pressure in the sealed drug solution storage container 1 rises, and the drug solution 2 passes through the pipe 6 whose temperature is controlled by the temperature controller 5 and the mist generator. 7 is supplied. as a result,
A mist of the chemical liquid 2 is generated in the mist generator 7 to which the carrier gas C2 is supplied from the supply port 8a. This mist has various particle sizes at this stage.

Thereafter, the mist is sent into the secondary tank 10, where mist having a size larger than a predetermined particle size is removed. As a result, the mist having a particle size on the order of micron is converted into a micro fog in the secondary tank. It is sent from 10 to the pipe 12. The reason for reducing the particle size in this way is to reduce the interaction with the vessel wall or the tube wall of the container or the pipe and prevent the adhesion, but since the critical particle size for this is different depending on the chemical solution, By operating the secondary tank 10, the particle size to be removed in the secondary tank 10 can be freely changed.

The chemical solution mist having a particle size on the order of micron sent from the secondary tank 10 to the pipe 12 is supplied to the supply port 12a.
With the clean air (carrier gas C3) supplied from the process chamber 2 through the flexible pipe 23.
It is sent to the mist dispenser nozzle 22 installed in 1. At the same time, the solvent mist is also supplied to the nozzle 22 through the solvent supply pipe 25 and the flexible pipe 24.

The chemical solution mist is supplied to the pipe 22a shown in FIG. 2, and enters the upper chamber 22f while passing through the R portion 22c. Although the flow velocity distribution of the mist flow entering the upper chamber 22f is not uniform, the nozzle holes 22 of the straightening plate 22d
By passing through e, a uniform flow velocity distribution can be obtained in the lower chamber 22g.

In this embodiment, since the chemical solution mist passing through the nozzle hole 22e of the straightening plate 22d has a small particle size of micro-fog, the dry chemical solution adheres to the nozzle hole 22e and the nozzle hole 22e is clogged. It is possible to prevent deterioration of reproducibility due to this.

On the other hand, the solvent mist flows in the chamber 22b in the direction of the arrow (dotted line) in the figure, changes the flow direction at the corner 22i, and flows toward the center of the tip of the nozzle 22. Then, the chemical mist and the solvent mist merge at the void 22h in FIG.

As a result, the chemical mist having a small particle size grows by being mixed with the solvent mist, the particle size becomes large, and the adhesive force thereof also increases. In addition, the supply flow rate of the chemical mist is set to be higher than the supply flow rate of the solvent mist, and the grown mist is flown to the injection port 22j side.

Returning to FIG. 1, the chemical liquid mist mixed and grown with the solvent mist in the above process is sprayed as a mixed mist onto the surface of the work 33. The mixed mist grows before reaching the work 33 and has a large adhesiveness. Therefore, when it reaches the surface of the work 33, the mixed mist adheres quickly.

Further, when the mixed mist discharged from the nozzle 22 is sprayed onto the surface of the work 33, the discharge needle 30 is used to charge the mixed mist midway. That is,
A high negative voltage is applied to the discharge needle 30 by a high-voltage power supply 31, which causes corona discharge at the tip of the discharge needle 30, ionization occurs near the tip of the discharge needle 30, and electrons are added to the mixed mist. To be done. Here, if the work 33 is set to the ground potential, the negatively charged mixed mist is concentrated and attached to the work 33.

At this time, the work 33 is rotating on the table 32 at a predetermined rotation speed determined by the rotation generating device 35 and the rotation transmitting device 34. The number of rotations is
It is optimized in advance together with the moving speed of the nozzle 22. This is because when the number of rotations is too high with respect to the moving speed of the nozzle 22, the film thickness of the applied chemical liquid becomes thinner than the set value, and when it is too small, it becomes too thick. . Further, if the nozzle 22 is moved from the inner circumference to the outer circumference of the substrate with the amount of chemical liquid discharged constant, the inner peripheral portion becomes thicker and the outer peripheral portion becomes thinner, but in this embodiment, in consideration of this point, the amount of chemical liquid discharged is taken into consideration. Is set to be constant, and the moving speed of the nozzle 22 is set to be high at the inner circumference and slow at the outer circumference.

If there is a possibility that the chemical solution may overflow to the table 32, for example, a device that can move the nozzle 22 in the vertical direction may be added to reduce the distance between the nozzle 22 and the work 33. . In this case, it is necessary to reduce the ejection amount to correct the film thickness uniformity.

FIG. 3 is a schematic diagram showing the structure of a chemical liquid coating apparatus according to the second embodiment of the present invention. Elements common to those in FIG. 1 are designated by the same reference numerals and their description is omitted.

Although the mist dispenser nozzle 22 is moved by the control rod 27 and the moving table 28 in the first embodiment, the control rod 27 and the moving table 28 are removed in the radial direction of the work 33 in the present embodiment. The structure is such that a plurality of nozzles corresponding to the nozzles 22 are provided.

More specifically, two nozzles 22a and 22b are provided inside the process chamber 21, and along with this, the process container 11, the pipe 12, the solvent mist supply pipe 16 and the flexible pipe 2 in the first embodiment.
Two pieces corresponding to the respective constituent elements of the 3, 24, the discharge needle 30, and the high voltage generator 31 are provided.

That is, the process vessels 11a, 11b,
Pipes 12a and 12b, solvent mist supply pipes 16a and 16
b, piping 23a, 23b, 24a, 24b, discharge needle 30
a, 30b and high voltage generators 31a, 31b are provided, and further, the respective pipes 12a, 12b and the secondary tank 10 are provided.
Valves 10a and 10b are attached between and. The carrier gas C3a is supplied from the supply port 12A of the pipe 12a, and the carrier gas C3b is supplied from the supply port 12B of the pipe 12b.

Even with this structure, the same effect as that of the first embodiment can be obtained.

[0060]

As described in detail above, according to the first aspect of the invention, since the chemical mist is made into microfog and blown out from the nozzle, it is possible to prevent clogging of the nozzle hole and improve reproducibility. However, since the generation of particles can be reduced and the mist applied to the substrate surface is converted from microfog to mixed mist having a large particle size, the adhesive force of the chemical solution to the substrate surface is improved. Further, since the chemical solution is conveyed in the microfog state, it is hardly affected by temperature / humidity. As a result, it is possible to apply the chemical liquid with high accuracy.

In the second aspect of the present invention, a predetermined potential is applied to the substrate in advance, and charges having a polarity opposite to the polarity of the predetermined potential are added to the mixed mist in the vicinity of the nozzle.
Dispersion of mist can be prevented and the yield is improved.

According to the third to fifth inventions, not only can the film thickness and the uniformity of the film thickness of the coating film be controlled with high accuracy, but there is no mechanical contact with the substrate for this control. There is less risk of fouling the membrane.

The sixth and seventh inventions have the same effects as the first invention.

The eighth and ninth inventions have the same effects as the second invention.

Due to the above effects, the supply amount of the chemical liquid such as the resist to the large diameter wafer or the large area liquid crystal panel can be significantly reduced as compared with the conventional spin coating method or the mist method. In this regard, since it is expected that the number of times the chemical solution is applied to the same substrate will increase as the degree of integration of semiconductors increases, its economic effect is remarkably large.

[Brief description of drawings]

FIG. 1 is a schematic view showing a configuration of a chemical liquid coating device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an internal configuration of a mist dispenser nozzle 22 in FIG.

FIG. 3 is a schematic diagram showing a configuration of a chemical liquid coating device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a conventional chemical liquid coating device.

5 is an internal configuration diagram of a nozzle 103 in FIG.

[Explanation of symbols]

 2 chemical liquid 7 mist generator 10 secondary tank 21 process chamber 22 mist dispenser nozzle 22e nozzle hole 26 solvent mist generator 27 control rod 28 moving table 30 discharge needle 31 high voltage generator 32 table 33 work

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03F 7/16 502

Claims (9)

[Claims] 1. A chemical liquid mist in which the particle size of the chemical liquid is reduced to the order of microns, and the chemical liquid mist is blown toward a surface of the substrate from a nozzle provided facing the substrate, the nozzle and the substrate A method for applying a chemical solution, characterized in that the chemical solution mist is brought into contact with the liquid mist to generate a mixed mist, and the mixed mist is applied to the surface of the substrate. 2. The predetermined potential is applied to the substrate in advance, and a charge having a polarity opposite to the polarity of the predetermined potential is added to the mixed mist in the vicinity of the nozzle. Chemical application method. 3. The substrate is configured to be rotatable and the nozzle is movable, and the application of the mixed mist to the substrate surface is performed by at least the discharge amount of the chemical liquid from the nozzle, the nozzle and the substrate. 2. The process is performed while controlling any one of the distance, the rotation speed of the substrate, and the moving speed of the nozzle.
The method for applying the chemical liquid described. 4. A substrate of the mixed mist, wherein an electrode plate is placed at a predetermined distance from the surface of the substrate, a potential difference is applied in advance between the electrode plate and the substrate, and the substrate is rotated. The method for applying a chemical liquid according to claim 1, wherein the application is performed on the surface. 5. The magnitude of the potential difference applied between the electrode plate and the substrate, the distance between the electrode plate and the surface of the substrate,
The chemical solution coating method according to claim 4, wherein the mixed mist is coated on the surface of the substrate while controlling the rotation speed of the substrate. 6. A chemical liquid mist generator for generating a chemical liquid mist in which the particle diameter of the chemical liquid is reduced to the order of microns, a liquid mist generator for generating a liquid mist, and a mixed mist by mixing the chemical liquid mist and the liquid mist. A chemical liquid coating apparatus comprising: a jetting nozzle; and a table on which a substrate is placed at a position facing the nozzle. 7. The chemical solution applying device according to claim 6, further comprising a secondary tank provided between the chemical solution mist generator and the nozzle for capturing mist having a large particle size. 8. A discharge electrode for adding an electric charge to the mixed mist is provided in the vicinity of the nozzle, and a potential difference is applied between the discharge electrode and the substrate. The chemical solution applying device according to claim 6. 9. The chemical solution according to claim 6, wherein an electrostatic attraction generating electrode plate is provided so as to face the substrate, and a potential difference is applied between the electrode plate and the substrate. Coating device.