JPH0957176A - Rotary applicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary applicator which can reduce the amount of chemical liquid to be discharged and discarded by predispensation without deteriorating the evenness of coat thickness. SOLUTION: An apparatus is equipped with a chemical liquid supply nozzle 10 for supplying chemical liquid and a waiting pot 20, and the chemical liquid supplied on the surface of a substrate W from a nozzle 10 at a chemical liquid supply position is spread by the rotation of the substrate W to form a chemical liquid coat. Besides, when the nozzle 10 is moved to a waiting position, its end part is inserted into the waiting pot 20. The atmosphere in the waiting pot 20 is kept at the same temperature as the control temperature of the chemical liquid by the control of a temperature control part 28 to control the viscosity variation of the chemical liquid deposited in the end part of the waiting nozzle 10.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor substrate, a glass substrate for a liquid crystal display, a glass substrate for a photomask, a substrate for an optical disk, etc. (hereinafter simply referred to as a substrate) in a horizontal posture while being rotated. , A photoresist coating, photosensitive polyimide, photosensitive resin such as color filter material, a glass solvent, a spin coating device that uniformly coats a chemical liquid such as a dopant material, especially the chemical liquid supply that supplies the chemical liquid onto the substrate The present invention relates to a device provided with a standby pot for keeping a nozzle on standby.

[0002]

2. Description of the Related Art In a conventional spin coating apparatus, after a chemical solution such as a photoresist solution is discharged to the central portion of the upper surface of a rotatably supported substrate, the substrate is rotated at a high speed so that the centrifugal force generated by the rotation of the substrate is increased. Then, the photoresist liquid is spread over the upper surface of the substrate to form a film (thin film) of the photoresist liquid. On the other hand, the chemical liquid supply nozzle moves from the discharge position (supply position) to the standby position on the side of the substrate after discharging the photoresist liquid, and the nozzle tip is inserted into the standby pot provided at the standby position. It has become. The standby pot receives the drips of the photoresist solution dripping from the tip of the nozzle, or prevents the solvent of the photoresist solution from evaporating from the tip of the nozzle to prevent the photoresist solution from solidifying to form a film. We are trying to make a smooth progress.

[0003]

However, the above-mentioned conventional spin coating apparatus has the following problems. That is, when the spin coating process is restarted after the operation of the spin coating apparatus is stopped for a certain period of time, for example, when the substrate group of one lot is continuously processed to start forming a film on the substrate group of the next lot, There is a tendency that the film thickness of the film formed on the film varies. It is believed that this is because when the nozzle tip portion is left in the standby pot for a long time, the characteristics of the photoresist liquid accumulated in the nozzle tip portion change for some reason. Therefore, when the tip of the nozzle is left in the standby pot for a certain period of time or longer, so-called pre-dispensing is performed in which the photoresist solution is slightly discharged and discarded before the spin coating process. However, since the photoresist solution is very expensive, such pre-dispensing is not preferable in terms of manufacturing cost, and there is a demand to reduce the amount of the photoresist solution discarded by the pre-dispensing as much as possible. Frequent pre-dispensing was forced to ensure the quality of the process.

The present invention has been made in view of the above circumstances, and provides a spin coating apparatus capable of reducing the amount of chemical liquid discharged and discarded by pre-dispensing without impairing the uniformity of the film thickness of the coating film. The purpose is to do.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor was able to obtain the following findings. Hereinafter, the case where the chemical solution is a photoresist solution will be specifically described as an example.

The temperature of the atmosphere around the substrate on which the spin coating process is performed (specifically, the clean air supplied to the hood in which the spin coating apparatus is housed) in order to form a uniform film of the photoresist solution. It is empirically recognized that it is preferable to set the temperature of the liquid crystal to be slightly lower than the control temperature of the photoresist liquid supplied from the nozzle, and the atmospheric temperature in the hood is set as such. As a result, the ambient temperature in the standby pot placed in this hood is also slightly lower than the control temperature of the photoresist liquid, so if the tip of the chemical solution supply nozzle is left in the standby pot for a long time, The temperature of the photoresist liquid accumulated at the tip portion was lowered, and the viscosity of the photoresist liquid was increased.

Further, in order to prevent the solvent of the resist solution from volatilizing from the tip of the nozzle, the solvent may be supplied into the standby pot to volatilize the solvent, so that the standby pot may be positively made into a solvent atmosphere. At this time, when the solvent volatilizes in the standby pot, the heat of vaporization is removed, so that the ambient temperature in the standby pot decreases. This also contributes to the decrease in the temperature of the photoresist solution accumulated at the tip of the nozzle and the increase in its viscosity.

In any case, the atmospheric temperature in the standby pot tends to be lower than the control temperature of the photoresist solution, which causes an increase in the viscosity of the photoresist solution, which deteriorates the uniformity of the coating film. Was found to have been.

The present invention obtained based on the above knowledge has the following configuration. That is, the spin coating apparatus according to the first aspect of the present invention supplies the chemical liquid to the upper surface of the rotatably supported substrate and moves between the chemical liquid supply position above the substrate and the standby position on the side of the substrate. And a standby pot installed at the standby position of the nozzle, and the chemical solution supplied from the nozzle at the chemical solution supply position to the surface of the substrate spreads by the rotation of the substrate. A coating film of the chemical solution is formed on the upper surface of the substrate, while the tip of the nozzle is inserted into the standby pot when the nozzle moves to the standby position. It is characterized in that a pot temperature adjusting means for maintaining the atmosphere at the same temperature as the control temperature of the chemical liquid is provided.

According to a second aspect of the present invention, in the spin coating apparatus according to the first aspect, the pot temperature adjusting means is a heat exchange means for exchanging heat with the standby pot, and the inside of the standby pot. And a control means for controlling the amount of heat exchange by the heat exchange means based on the output of the temperature detection means.

[0011]

The operation of the invention described in claim 1 is as follows. Since the atmosphere in the standby pot is maintained at the same temperature as the control temperature of the chemical liquid by the pot temperature adjusting means, the temperature of the chemical liquid accumulated at the tip portion of the chemical liquid supply nozzle while the tip portion is in the standby pot. Fluctuation can be suppressed. Since the temperature fluctuation of the chemical liquid is directly related to the viscosity fluctuation of the chemical liquid, if the temperature fluctuation of the chemical liquid can be suppressed, the viscosity fluctuation of the chemical liquid can also be suppressed. Further, since the chemical solution whose viscosity variation is suppressed does not impair the uniformity of the film thickness even if it is directly supplied to the upper surface of the substrate, it can be used without being discarded, and therefore the necessity of pre-dispensing is reduced. For example, the down time of the device operation that requires pre-dispensing will be much longer than before.

According to the spin coating apparatus of the second aspect,
The pot temperature control means is a system in which the amount of heat exchange between the heat exchange means and the standby pot is controlled according to the temperature in the standby pot,
That is, since it is a feedback system, the temperature control accuracy is high and the temperature in the standby pot is strictly maintained at the same temperature as the control temperature of the chemical liquid. As a result, the temperature fluctuation of the chemical liquid can be suppressed to a smaller extent, and the fluctuation of the viscosity of the chemical liquid becomes much smaller accordingly, which further reduces the need for pre-dispensing.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the spin coating apparatus of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic structure of a spin coating apparatus according to an embodiment, FIG. 2 is a partial sectional view of a chemical liquid supply nozzle of the embodiment apparatus, and FIG. 3 is a sectional view showing a structure of a standby pot of the embodiment apparatus. .

In this spin coating apparatus, a rotary base 3 for vacuum-holding a substrate W on which a film is to be formed in a horizontal posture is integrally provided on the upper end of a rotary shaft 2 which is rotated about an axis in the vertical direction by driving an electric motor 1. It is rotatably attached.

The periphery of the rotary table 3 is covered with a cup 4 which can be moved up and down by an elevator drive mechanism (not shown). Substrate W
When loading / unloading the substrate, the cup 4 is moved downward so that the substrate W is placed on or removed from the turntable 3, and at the time of forming a film on the substrate W (when the substrate W is rotated),
The cup 4 is moved upward to prevent the chemical solution (photoresist solution or the like) supplied onto the substrate W from scattering. The surplus chemical liquid scattered in the cup 4 is discharged through the drain pipe 4a, and the inside of the cup 4 is discharged through the exhaust duct 4b. An opening 6 for loading / unloading the substrate W by using a transfer robot (not shown) is provided on a side wall of the hood 5 in which the spin coating apparatus is housed, and the opening 6 is opened and closed by a shutter 7. There is.

An air supply port 8 is provided above the hood 5, and clean constant temperature air is constantly flowing in from the air supply port 8 so that the clean constant temperature air flows down in the hood 5. The inside of the hood 5 is always kept at an appropriate temperature (a temperature slightly lower than the control temperature of the film forming chemical solution), and the inside of the hood 5 is always kept in a clean atmosphere.

A chemical solution supply nozzle 10 for supplying a chemical solution such as a photoresist solution to the upper surface of the substrate W held on the turntable 3 is arranged laterally of the cup 4. The chemical solution supply nozzle 10 is cantilevered by a support member 11 that can be rotated and moved up and down, and is configured to be movable between a chemical solution supply position shown by a chain line in FIG. 1 and a standby position shown by a solid line.

The structure of the chemical liquid supply nozzle 10 will be described with reference to FIG. Along the central axis of the chemical liquid supply nozzle 10, there is a chemical liquid supply tube 12 through which a chemical liquid pressure-fed from a chemical liquid tank (not shown) flows, and a tip end portion 13 of the chemical liquid supply tube 12 is connected in communication with the tip of the chemical liquid supply tube 12. The chemical liquid supply tube 12 is surrounded by an inner tube 14 with a gap, and the inner tube 14 is surrounded by a metal outer tube 15 with a gap, and the tip of the outer tube 15 is joined to the base of the nozzle tip 13. Has been done. By opening the tip of the inner tube 14, an annular inner channel 16 formed by the chemical liquid supply tube 12 and the inner tube 14 and an annular inner channel formed by the inner tube 14 and the outer tube 15 are formed. The outer flow path 17 communicates with the mounting base end portion of the nozzle tip portion 13. Then, the constant temperature water is fed from the proximal end side of the inner flow path 16 so that the chemical liquid in the chemical liquid supply tube 12 is maintained at a predetermined control temperature. The constant temperature water that has flowed through the inner flow path 16 is at the base end side of the nozzle tip portion 13 and the outer flow path 17
And is collected via this outer flow path 17.

On the other hand, a standby pot 20 is provided at the standby position of the chemical solution supply nozzle 10. The chemical liquid supply nozzle 10 that has moved to the standby position with the rotation of the support member 11 moves slightly downward, and as shown in FIG.
3 is inserted from the opening 21 of the standby pot 20 and is kept in a standby state until the next chemical liquid discharge.

The inside of the standby pot 20 is in a solvent atmosphere. That is, the solvent is sent from the solvent supply pipe 22 that passes through the inside of the standby pot 20 to the bottom of the standby pot 20 and is stored therein, and the solvent volatilized from the solvent creates a solvent atmosphere in the standby pot 20. Therefore, the solvent volatilization of the chemical liquid from the nozzle tip portion 13 is suppressed, and the viscosity increase of the chemical liquid can be prevented. Further, the inside of the standby pot 20 is always exhausted through a discharge port 23 provided on the bottom side.

The atmosphere in the standby pot 20 is maintained at the same temperature as the control temperature of the chemical liquid (for example, 23 ° C.) by the pot temperature adjusting means described below. That is, in the standby pot 20, a constant temperature water flow path (heat exchange means) 24 is arranged so as to circulate around the pot wall, and a temperature sensor (temperature detecting means) 25 for detecting the temperature in the pot is provided. is set up. In the flow path 24 in the wall of the standby pot 20,
One end of the constant temperature water inflow pipe 26 and one end of the outflow pipe 27 are connected to each other, and the other ends of the inflow pipe 26 and the outflow pipe 27 are taken into the temperature control unit 28. By sending a detection signal from the temperature sensor 25 to the temperature control unit 28, the temperature control unit 28 adjusts the temperature of the constant temperature water according to the temperature in the standby pot 20. That is, the temperature control unit 28
The constant temperature water supplied from circulates in the wall passage 24 of the standby pot 20 through the inflow pipe 26, during which heat is exchanged with the atmosphere in the standby pot 20, and then through the outflow pipe 27. Returning to the temperature control unit 28, the temperature control unit 28 adjusts the temperature of the constant temperature water according to the ambient temperature in the standby pot 20 detected by the temperature sensor 25. It is maintained at the same temperature as the control temperature of the chemical liquid (photoresist liquid). As described above, the pot temperature adjusting means of the present embodiment is of a feedback type, and the atmosphere in the standby pot 20 is controlled and maintained so as to be the same temperature as the control temperature of the chemical liquid. As a result, the temperature fluctuation of the chemical liquid is suppressed to be small and the viscosity fluctuation of the chemical liquid is suppressed.

In the present invention, maintaining the atmosphere in the standby pot at the same temperature as the control temperature of the chemical liquid means that the atmosphere in the standby pot and the control temperature of the chemical liquid are completely the same, for example, the type of the chemical liquid. It also includes the case where a minute temperature difference is provided between the atmosphere in the standby pot and the control temperature of the chemical liquid due to the difference in To keep the same.

A film forming process on the substrate W by the spin coating apparatus of the embodiment configured as described above will be described. After the cup 4 is lowered, the shutter 7 is opened and the substrate W is loaded into the hood 5 and placed on the turntable 3, the shutter 7 is closed. Subsequently, the chemical liquid supply nozzle 10 is rotated from the standby position to the chemical liquid supply position, and the necessary amount of chemical liquid is discharged and supplied from the nozzle tip portion 13 onto the upper surface of the substrate W. After discharging and supplying the chemical liquid, the chemical liquid supply nozzle 10 is moved from the chemical liquid supply position to the standby position, and the nozzle tip portion 13 is inserted into the standby pot 20. By raising the cup 4 and rotating the substrate W by the electric motor 1 at a predetermined number of rotations to spread the chemical liquid, a film is formed on the upper surface of the substrate W.
At this time, in the apparatus of the embodiment, since the atmosphere in the standby pot 20 is strictly maintained at the same temperature as the management temperature of the chemical liquid, the temperature of the discharged chemical liquid has a small deviation from the management temperature. . Therefore, the fluctuation of the viscosity of the chemical liquid is small, and the uniformity of the film thickness can be ensured. After the film is formed, the rotation of the substrate W is stopped, the cup 4 is lowered, the shutter 7 is opened, and the substrate W is unloaded. After that, the same operation as described above is repeated to successively form a film on the upper surface of the substrate W.

The spin coating apparatus of the present invention can be modified and implemented as follows. (1) In the above embodiment, the pot temperature adjusting means is a feedback type, but it may be an open loop type temperature adjusting means. Specifically, another example is a configuration in which constant-temperature water of a sufficient amount is constantly flowed to maintain the atmosphere in the standby pot at the same temperature as the control temperature of the chemical liquid.

(2) In the above embodiment, the pot temperature control means is a heat exchange system utilizing the heat of the constant temperature water, but by energizing the electric heater or the Peltier element embedded in the wall of the standby pot. A heat exchange method of utilizing generated heat may be used. Also in this case, both the feedback method and the open loop method are possible.

(3) In the above-described embodiment, the number of nozzles for supplying the chemical liquid is one, but a plurality of nozzles are provided to selectively supply chemical liquids of different types and viscosities to the upper surface of the substrate W. An apparatus having a configuration capable of doing so is also given as another example.

(4) Although the above embodiment has the hood, the present invention can be applied to an apparatus having no hood.

(5) In the spin coating apparatus of the present invention, the chemical liquid supplied by the nozzle is not limited to a specific chemical liquid, and in addition to the photoresist liquid shown in the embodiment, for example, a coating film such as a polyimide resin liquid. Examples include various chemical solutions used for formation.

(6) In the above embodiment, the inside of the standby pot has a solvent atmosphere, but the inside of the standby pot may simply have an air atmosphere.

[0030]

As is clear from the above description, according to the spin coating apparatus of the first aspect, the variation in the viscosity of the chemical liquid is suppressed, so that the uniformity of the film thickness formed on the upper surface of the substrate is impaired. In addition, since the necessity of pre-dispensing is reduced, the amount of chemical liquid discarded by pre-dispensing can be reduced.

According to the spin coating apparatus of the second aspect,
The temperature in the standby pot is strictly maintained at the same temperature as the control temperature of the chemical liquid by the feedback type pot temperature control means with high temperature control accuracy, so the temperature fluctuation of the chemical liquid becomes smaller and it is formed on the upper surface of the substrate. The uniformity of the coating thickness can be further improved, the need for pre-dispensing can be further reduced, and the amount of discarded chemical liquid can be further reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a spin coating device according to an embodiment.

FIG. 2 is a partial cross-sectional view showing the configuration of the chemical liquid supply nozzle of the embodiment apparatus.

FIG. 3 is a cross-sectional view showing a configuration of a standby pot of the apparatus of the embodiment.

[Explanation of symbols]

 10 ... Chemical Supply Nozzle 13 ... Nozzle Tip 20 ... Standby Pot 24 ... Constant Temperature Water Flow Path 25 ... Temperature Sensor 28 ... Temperature Controller W ... Substrate

Claims (2)

[Claims] 1. A chemical solution supply nozzle which supplies a chemical solution to an upper surface of a rotatably supported substrate and is arranged so as to be movable between a chemical solution supply position above the substrate and a standby position on the side of the substrate. A standby pot installed at the standby position of the nozzle, and the chemical solution supplied from the nozzle at the chemical solution supply position to the surface of the substrate is spread by the rotation of the substrate to form a film of the chemical solution on the upper surface of the substrate. On the other hand, in the spin coating apparatus configured such that the nozzle tip portion is inserted into the standby pot when the nozzle moves to the standby position, the atmosphere in the standby pot is maintained at the same temperature as the chemical management temperature. A spin coating device comprising a pot temperature adjusting means for controlling the temperature. 2. The spin coating apparatus according to claim 1, wherein the pot temperature adjusting means exchanges heat with the standby pot, and a temperature detecting means for detecting an ambient temperature in the standby pot. A spin coating device comprising: a control unit that controls the amount of heat exchange by the heat exchange unit based on the output of the temperature detection unit.