JP2001062379A - Coating method and coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To even the delivery quantity of a solvent to be sprayed every coating before spray coating, by always fixing the liquid level of the solvent in the piping at a constant position. SOLUTION: In a coating device where a solvent, which is liquid, and a gas are supplied at the same time to be mixed in the tip end of a spray nozzle 17, and a substrate W to be treated is subjected to spray coating, it is controlled so that only the gas is supplied from a gas supply system 7 to a spray gun 17a for a predetermined time immediately before the spray coating. Thereby, remaining solvent is blown off by the gas at the downstream side of a mixing part where a liquid supply system 8 of the spray nozzle 17 meets the gas supply system 7. As a result, the liquid level at the end of the downstream side of the solvent is made to be always positioned at the mixing part, thereby making the delivery quantity of the solvent constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method and a coating apparatus, and more particularly, to forming a liquid coating film using a solvent such as a resist film on a substrate to be processed such as a semiconductor wafer or a mask substrate. TECHNICAL FIELD The present invention relates to a coating method and an apparatus for uniformly coating on a layer formed.

[0002]

2. Description of the Related Art Conventionally, a coating liquid is applied to a substrate for forming a precise pattern (hereinafter, referred to as a "substrate") such as a semiconductor wafer for a semiconductor manufacturing apparatus, a glass substrate for manufacturing various displays and a photomask. 2. Description of the Related Art A coating technique using a so-called rotary coating apparatus is known, in which the coating liquid is applied by spreading the coating liquid over the entire surface of a substrate to be processed by dropping and applying a rotary centrifugal force.

As is well known, in the field of semiconductor technology, when a semiconductor layer, an insulator layer, and an electrode layer formed on a semiconductor wafer are selectively etched into a predetermined pattern,
A resist film is formed on the surface of a layer as masking of a pattern portion.

As a method of forming the resist film, a resist solution composed of a solvent and a photosensitive resin is dropped on the center of the upper surface of the wafer by the above-described coating method using a spin coater, and the resist solution is subjected to the rotational force of the wafer and the centrifugal force. The coating is performed by diffusing from the central portion of the wafer toward the peripheral portion by force.

In this method, the solvent in the resist solution evaporates in the process of diffusing the resist solution from the center position of the wafer toward the periphery. For this reason, the viscosity of the resist solution differs in the diffusion direction, and the thickness of the formed resist film differs between the central portion and the peripheral portion. That is,
There was a limit to uniform application.

For this reason, conventionally, there has been proposed a method of dropping a solvent of a resist solution onto a wafer surface before applying the resist solution. Further, a spray-type coating apparatus using a two-fluid nozzle that mixes a solvent with a gas on a wafer and sprays the solvent uniformly so as to uniformly apply the solvent is used.

[0007]

However, since the solvent used as a solvent has volatility, if the nozzle is left for a long time, the solvent volatilizes, and the liquid level at the downstream end of the solvent in the nozzle pipe recedes, and the pipe is not used. The amount of the solvent in the inside varies.
Therefore, there has been a problem that the discharge amount of the solvent next time fluctuates. As a result of the variation in the discharge amount of the solvent, the application of the resist was uneven.

This state becomes remarkable when the coating standby time from when the coating of the solvent is stopped to when the coating is started becomes relatively long. This means that even when the fluctuation amount is small, the ratio of the solvent to the total amount of the solvent is large when the solvent is applied before the application of the resist solution with a small amount of the solvent, so that there is a problem in that the processing variation between wafers is increased. .

The present invention provides a coating method and a coating apparatus capable of discharging an optimal amount of a coating liquid from a highly volatile liquid regardless of the length of the coating standby time, thereby achieving uniform coating. It is in.

[0010]

Means for Solving the Problems and Their Functions and Effects The present invention has the following configuration in order to achieve such an object. That is, the invention according to claim 1 is a coating method in which a liquid and a gas are simultaneously supplied, mixed at the tip of the spray nozzle, and spray-coated on the substrate to be processed. The method is characterized in that a step of supplying only a gas for a predetermined time is followed by a step of spray coating the substrate to be processed.

According to a second aspect of the present invention, in the coating method according to the first aspect, a processing step of discharging and discarding only a small amount of liquid is performed before the step of supplying only gas. .

The invention according to claim 3 is the coating method according to claim 1 or 2, wherein the liquid has volatility.

According to a fourth aspect of the present invention, in the coating method according to any one of the first to third aspects, the step of supplying only the gas for a predetermined time is performed when the spray nozzle is in a standby position. After the step of supplying only gas for a predetermined time is completed, the spray nozzle moves to an application position to perform a spray application step.

According to a fifth aspect of the present invention, there is provided a coating apparatus for simultaneously supplying a liquid and a gas, mixing the liquid and gas at the tip of the spray nozzle, and spray-coating the substrate to be processed, wherein the liquid is supplied to the spray nozzle. A liquid supply system, a gas supply system that supplies a gas that joins the liquid supply system, and a control unit that controls operations of the liquid supply system and the gas supply system,
The control means controls to supply only gas for a predetermined time from the gas supply system to the spray nozzle immediately before performing the spray coating.

The invention according to a sixth aspect is the coating apparatus according to the fifth aspect, wherein the control means includes a timing instructing means for instructing an operation timing of the liquid supply system and the gas supply system; Discharge control means for controlling discharge of liquid or gas from the liquid supply system and the gas supply system in accordance with a signal from the timing instruction means, and completion of gas supply from the gas supply system from the timing instruction means. The spray control is performed by the discharge control means in response to the above signal.

The invention according to claim 7 is the coating apparatus according to claim 5 or 6, wherein the control means controls the liquid supply system before supplying only the gas from the gas supply system. It is characterized in that control is performed such that only a small amount of liquid is discharged and discarded.

The operation of the present invention is as follows. In the coating method according to the first aspect of the invention, a step of supplying only the gas for a predetermined time is performed immediately before the step of simultaneously supplying the gas and the liquid to perform the spray coating. Then, a spraying process is performed through the process. Therefore, immediately before the spraying step, the liquid is blown off by the gas on the downstream side of the gas-liquid mixing portion of the spray nozzle. Therefore, the liquid surface at the downstream end of the liquid in the spraying step is always located at the mixing site, and the discharge amount of the liquid is constant.

In the coating method according to the second aspect of the present invention, a small amount of liquid is discharged and discarded before the step of supplying only gas in the coating method according to the first aspect. Therefore, even if the liquid accumulated in the spray nozzle has changed in characteristics, such a liquid is discarded and uniform application can be performed. In addition, even if the discharge of only the liquid is performed and the liquid remains up to the tip in the spray nozzle, only the gas is supplied thereafter, and the liquid is discharged by the gas downstream of the gas / liquid mixing portion of the spray nozzle. Blown away. Therefore, the liquid surface at the downstream end of the liquid in the spraying step is always located at the mixing site, and the discharge amount of the liquid is constant.

In the coating method according to the third aspect of the present invention, the liquid used in the coating method according to the first or second aspect has volatility. In the case of a liquid having volatility, the fluctuation of the liquid amount in the spray nozzle is more remarkable due to volatilization. However, in the gas-only supply step, the liquid surface at the downstream end of the liquid is always defined at the mixing portion, and the discharge amount of the liquid is constant.

According to a fourth aspect of the present invention, in the coating method according to any one of the first to third aspects, the step of supplying only gas is performed while the spray nozzle is at the standby position. After the completion of the process, the spray nozzle moves to the application position, and the spray application process is performed. That is, since the downstream end liquid level of the liquid is set to the mixing portion of the liquid and the gas by the supply of only the gas, the spraying step is performed,
It is possible to prevent the liquid level from fluctuating due to further volatilization of the liquid. Further, since the time during which the liquid is placed on standby is set to the minimum time, which is the moving period of the spray nozzle, further fluctuation after the liquid level is defined can be minimized.

In the coating apparatus according to the fifth aspect of the present invention, the liquid supply system and the gas supply system are controlled by the control means so that the gas and the liquid are supplied simultaneously and immediately before the spray coating is performed, only the gas is predetermined. Supply time. Therefore, immediately before the spray coating is performed, the remaining liquid is blown off by the gas on the downstream side of the gas-liquid mixing portion of the spray nozzle. Therefore, the liquid surface at the downstream end of the liquid in the spray application is always located at the mixing portion, and the discharge amount of the liquid is constant.

In the coating apparatus according to the present invention, in response to a signal indicating completion of gas supply from the gas supply system from the timing instruction means, the discharge control means simultaneously supplies gas and liquid to perform spray coating. . In other words, since the spraying step is performed after the liquid level at the downstream end of the liquid is set to the mixing portion of the liquid and the gas by supplying only the gas, the liquid can be prevented from further volatilizing and the liquid level position fluctuating.

According to a seventh aspect of the present invention, only a small amount of the liquid is discharged and discarded before supplying only the gas from the gas supply system in the coating apparatus according to the fifth or sixth aspect. Therefore, even if the liquid accumulated in the spray nozzle has changed in characteristics, such a liquid is discarded and uniform application can be performed. Further, even if the discharge only of the liquid is performed and the liquid remains up to the tip portion in the spray nozzle, only the gas is supplied thereafter and the gas remains at the downstream side of the gas / liquid mixing portion of the spray nozzle. The liquid is blown off.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a schematic configuration of a rotary substrate coating apparatus according to the present invention to which the method of the present invention is applied.

In FIG. 1, reference numeral 1 denotes a suction-type spin chuck which sucks and supports a substrate W in a substantially horizontal posture. The suction type spin chuck 1 is driven by a rotary motor 3 via a hollow rotary shaft 2, and is rotated around the vertical axis together with the substrate W by the drive of the rotary motor 3. Around the suction type spin chuck 1, a scattering prevention cup 5 for preventing scattering of a coating liquid such as a photoresist solution is provided. Although not shown, the scattering prevention cup 5 and the rotating shaft 2 are configured to move up and down relatively, and the unprocessed substrate W is loaded into the scattering prevention cup 5 in a state where they are moved up and down relatively. Processed substrate W
Is carried out of the scattering prevention cup 5.

Above the scattering prevention cup 5, the substrate W
Above the center of rotation of the photoresist W
A coating liquid discharge nozzle 11 that discharges the liquid is provided. The coating liquid discharge nozzle 11 is supplied with a photoresist liquid as a coating liquid from a coating liquid supply unit 13, and the driving unit 15 moves the tip of the nozzle to a supply position shown in FIG. 5 is oscillatingly moved to a stand-by position (not shown) separated to the side.

Further, a solvent spray nozzle (hereinafter referred to as a spray nozzle) 17 for spraying the solvent (liquid) in the form of a mist onto the substrate W is arranged in parallel with the coating liquid discharge nozzle 11 to constitute a solvent supply mechanism 6. ing. The solvent supply mechanism 6 includes a solvent (liquid) supply system 8 for supplying a solvent connected to the spray nozzle 17 via a pipe, and a gas supply system 7 for supplying a gas such as N ₂ mixed to atomize the solvent. And

The spray nozzle 17 is composed of a two-fluid nozzle described later for spraying the solvent from the solvent supply source 19, and discharges the solvent to the upper surface of the substrate W held by the spin chuck 1 in the processing chamber. , Apply. The spray nozzle 17 has N 2 pressurized through an electromagnetic on-off valve 21.
_Two gases are supplied. Therefore, as shown by the dotted line in FIG. 1, when the electromagnetic on-off valve 21 is opened, the solvent is sprayed from the spray gun 17a attached to the tip of the spray nozzle 17, and the solvent is sprayed in a range almost covering the radius of the substrate W. It is supposed to be. The spray gun 17a may have a spray range covering the entire surface of the substrate W.

Further, the spray nozzle 17 is
Thus, it is configured to swing between a supply position shown in FIG. 1 and a standby position located beside the scattering prevention cup 5. At the same time, when the solvent is sprayed without rotating the substrate W, it is configured to be movable so as to scan a predetermined range from the supply position so that the solvent can be sprayed over the entire surface of the substrate W. In the standby position, a container for receiving the solvent to be discharged and disposed may be provided.

Next, the spray gun 17a, the solvent supply system 8 and the gas supply system 7 will be described with reference to FIG. The solvent supply system 8 includes a solvent supply source 19 including a container 81 for storing the solvent, a pressurizer for pressurizing and feeding the stored solvent (not shown), a flow meter 82, a filter (filter) 83, and an electromagnetic on-off valve 19a. Through the spray gun 17 by the pipe 19b.
a is connected to a pipe.

The gas supply system is provided with a gas supply body 71 of a gas such as N ₂ for atomizing the solvent liquid, a flow rate system 72, and a filter 73 in order in the pipe 7a. 17a.

The spray gun 17a is, as shown in FIG.
It is composed of a liquid supply nozzle 17b connected to the solvent supply system 8 and a gas supply nozzle 17c connected to the gas supply system 7 near the tip of the liquid supply nozzle 17b. Defined at the mixing site. Mixed solvent and N ₂ is between the cavity and the mixing zone of the diffusion hole 17d provided in the front end hole inner wall of the spray gun 17a are adapted to the solvent is ejected in a mist form. If the opening angle of the diffusion hole 17d is too small, it does not form a mist, and if it is too large, there is useless ejection in the lateral direction. Therefore, a spray shape of, for example, about 45 to 90 degrees is desirable.

The above-described rotary motor 3 and coating liquid supply unit 1
3, the drive unit 15, the solvent supply mechanism 6, and the solenoid on-off valve 1
9a, 21 and the drive unit 23 are controlled by the control unit 31. The control unit 31 controls each of the above units by a processing program stored in the memory 33 in advance and according to a time chart described later. That is, the control unit 31 and the memory 33 constitute the control unit of the present invention, and the function of the control unit 31 for giving a timing instruction according to the time chart is used for the timing instruction unit, and the function for controlling the ejection operation from the spray nozzle 17 is used for the ejection control. It corresponds to a means.

In the coating apparatus having the above structure, the photoresist liquid supplied from the coating liquid supply unit 13 is, for example, a positive type liquid comprising a quinonediazide photosensitive material, an alkali-soluble phenol resin and an organic solvent. Examples of the organic solvent to be contained include those mainly containing ECA (ethyl cellosolve acetate), EL (ethyl lactate), PGMEA (propylene glycol monomethyl ether acetate) and the like.

As the solvent stored in the solvent supply source 19, the same kind of organic solvent as the solvent contained in the photoresist solution may be used. For example, PGMEA (propylene glycol monomethyl ether acetate) or EL used as a main solvent of a photoresist solution
(Ethyl lactate) and the like can be used.

Next, referring to the time chart of FIG.
The photoresist liquid coating process will be described. A processing program corresponding to this time chart is stored in the memory 33 shown in FIG. 1 in advance, and is executed by the control unit 31. Further, it is assumed that the substrate W to be processed is already mounted on the suction-type spin chuck 1 and held by suction, and the spray nozzle 17 is waiting at the standby position.

First, the rotation drive of the rotation motor 3 is started. Specifically, the control unit 3 controls the spin chuck 1 to reach the rotation speed R1 (for example, 100 rpm) at time t1.
1 drives the rotation motor 3 forward. On the other hand, the spray nozzle 17 opens the electromagnetic on-off valve 19a at time t11 and performs a process of discharging and discarding only a small amount of the solvent (hereinafter, predispensing) until time t12. This is spray gun 17
This is performed for the purpose of maintaining the uniformity of the coating liquid by ejecting and discarding the portion whose characteristics have changed with the solvent that has been placed on standby at the leading end for a certain time or longer.

Next, supplies _{N 2} opens the electromagnetic valve 21 is closed and the solenoid valve 19a in time t12. Supply of the _{N 2} continues to t13. As a result, the solvent remaining on the downstream side of the mixing portion of the spray gun 17a is blown off by the above-described predispensing. The liquid level at the downstream end of the solvent is defined at the mixing site by blowing off the gas. The transition from the pre-dispense to the gas-only supply step may not be simultaneous at the same time, and the processing may be continued with a time lag.

When the electromagnetic on-off valve 21 is closed at time t13, the spray nozzle 17 is moved from the standby position to the supply position by the drive unit 23. When the spray nozzle 17 is located at the supply position at time t14, a solvent spray application process is performed.

At a time point t14 when the rotation speed of the substrate W is stabilized at the rotation speed R1, the electromagnetic on-off valves 19a and 21 are opened to supply the solvent from the spray nozzle 17 in the form of a mist. The on-off valve 19a is closed, and the electromagnetic on-off valve 21 is closed slightly later to stop the supply. That is, the time from the time t14 to the time t15 is the solvent spraying time, and the amount of the solvent supplied during this time is as follows:
For example, 0.3 milliliter. The reason why the electromagnetic on-off valve 21 is closed late is to prevent liquid dripping from the tip of the spray gun 17a.

Here, in order to close the electromagnetic on-off valve 21 with a delay, the liquid level at the downstream end of the solvent is defined at the mixing site as in the step (t12 to t13). Then, a waiting period is set until the next solvent application, during which time the solvent evaporates and the liquid level may recede from the mixing site. If the liquid surface at the downstream end recedes from the mixing portion, even if only the gas is supplied, the function of defining the liquid surface does not work, but in the first embodiment, the pre-dispensing step (t11 to t12) is performed. Therefore, the operation of the liquid level regulation is not impaired.

After time t15 when the supply of the solvent is stopped, the drive unit 23 moves the spray nozzle 17 to the standby position, and instead, the drive unit 15 moves the application liquid discharge nozzle 11 to the supply position. .

Next, the rotation speed is increased at time t2 so that the rotation speed of the substrate W reaches the rotation speed R2 (for example, 1000 rpm) at time t3. Then, at the time point ts at which the rotation speed R2 is stabilized, the supply of the photoresist liquid from the application liquid discharge nozzle 11 is started at a constant flow rate, and the supply of the photoresist liquid is stopped at the time point te when the supply time Tse is reached.

Therefore, before the entire surface of the substrate W is covered with the photoresist liquid R supplied to the surface of the substrate W, the rotation speed is increased to a rotation speed R3 (for example, 2500 rpm) higher than the rotation speed R2 (1000 rpm). Start to raise (time t4). At this time, the rotation speed is controlled to start increasing at time t4 and reach the rotation speed R3 at time t5.
During this time, for example, about 0.1 sec.

Since the solvent is previously applied to the entire surface of the substrate W as described above, the contact angle between the photoresist solution and the surface of the substrate W is extremely small. Therefore, the diameter of the photoresist solution is rapidly increased, and the time required for the entire surface of the substrate W to be covered with the photoresist solution is significantly reduced as compared with the related art.

In this manner, the entire surface of the substrate W is covered with the photoresist solution. At time t7, the rotation speed of the substrate W is reduced to the rotation speed R4 (for example, 1500 rpm), and the rotation speed R4 is reduced from time t7 to time t8. By holding the photoresist liquid, the surplus of the photoresist liquid covering the entire surface of the substrate W is shaken off. As a result, a photoresist film having a desired thickness is formed on the surface of the substrate W.

As described above, the solvent is applied before supplying the photoresist solution of the substrate W, and the contact angle between the photoresist solution and the surface of the substrate W is reduced. The diameter of the liquid can be easily expanded. Further, since the solvent to be supplied is sprayed prior to the photoresist liquid, the solvent can be supplied over a wide range in a short time, and even if the surface of the substrate W has irregularities such as a circuit pattern, the solvent is applied to that part. Since the stagnation can be suppressed, unevenness due to the solvent can be prevented from being generated in the photoresist film.

Further, the discharge amount of the solvent is always set at a fixed position in the spray nozzle 17 in the spray nozzle 17 in the gas supply step (t12 to t13) performed immediately before the solvent application. The amount is also constant. In other words, the amount of the solvent in the spray nozzle 17 fluctuates as the solvent retreats in the spray nozzle 17 due to its volatility in the spray nozzle 17 at the downstream end, but the discharge amount can be kept constant.

Further, since the supply step of the gas only is performed immediately before the solvent spray coating step (t14 to t15) with the moving period of the spray nozzle 17 (t13 to t14), after the liquid level is defined. The fluctuation of the volatilization amount of the solvent is minimized.

Next, referring to the time chart of FIG. 4, a description will be given of a photoresist liquid coating process according to the second embodiment. The apparatus for performing this coating process is the same as the configuration shown in FIG. 1 described above, and the only difference is that the processing program stored in the memory 33 is as follows.

First, unlike the first embodiment, the second embodiment does not perform solvent predispensing. Then, when the spray nozzle 17 is in the standby position, only the gas is supplied (t2).
2 to t23) and after moving the spray nozzle 17 (t
In step 24), the solvent is sprayed without driving the rotary motor 3 in a state where the substrate W is sucked and held by the suction-type spin chuck 1, that is, in a state where the substrate W is stationary (t24).
To t25). Specifically, the drive unit 23 sprays the solvent from the spray nozzle 17 onto the surface of the substrate W from the spray nozzle 17 at time t24 and starts supplying the solvent to the entire surface of the substrate W within the solvent spraying time until time t25. To move the spray gun 17a.

When the spraying of the solvent is stopped at the time point t25, the supply of the solvent by the solvent supply system 8 is stopped after the supply of N ₂ by the gas supply system 7 is stopped. The timing of stopping procedure may be shifted to stop slightly solvent supply system 8, will be slightly supplied only solvent after stop of the supply of N ₂ in this way, always the downstream end surface of liquid solvent spray gun 17a Will be defined downstream from the mixing site.

Next, at time ts, the supply of the photoresist liquid from the coating liquid discharge nozzle 11 is started, and the supply time Ts
When e elapses, the supply is stopped at time te. That is, the supply of the photoresist liquid is completed with the substrate W kept still.

At time te, the supply of the photoresist solution is stopped, the rotation speed of the substrate W is increased toward the rotation speed R2, and this is maintained from time t1 to time t2. Acceleration is started from time t2 so that the number reaches the rotation speed R3. At this time t2
Is set before covering the entire surface of the substrate W.

As described above, in the second embodiment, the pre-dispensing is not performed, but the liquid level at the downstream end of the solvent is positively positioned downstream of the mixing portion when the spray coating of the solvent is stopped. By doing so, the next time the gas-only supply step is performed, the solvent existing on the downstream side is always blown out from the mixing site to define the liquid level.

As the control at the time of stopping the spray coating,
The supply of the solvent and N ₂ may be stopped at the same time. In this way, the blown-off solvent remains to a considerable extent downstream of the mixing portion of the spray gun 17a, and the next gas-only supply step (t11 to t12)
Will be blown away.

In the first and second embodiments,
Although a photoresist liquid has been described as an example of the coating liquid, the method of the present invention can be applied to a coating liquid such as an SOG liquid (Spin On Glass, also referred to as a silica-based film forming material) or a polyimide resin.

In the above description, the spraying of the solvent is performed in the coating apparatus. However, after the solvent spraying is performed in a separate apparatus, the coating liquid is coated in the coating apparatus. You may.

[0059]

According to the first aspect of the present invention, there is provided an application method in which a liquid and a gas are simultaneously supplied, mixed at the tip of a spray nozzle, and spray-coated on a substrate to be processed. And supplying the gas only for a predetermined time immediately before the step of supplying the gas and the liquid at the same time and performing the spray coating by simultaneously supplying the gas and the liquid. Perform the process. Then, a spraying process is performed through the process. Therefore, immediately before the spraying step, the residual liquid is blown off by the gas on the downstream side of the gas-liquid mixing portion of the spray nozzle.
Therefore, the liquid surface at the downstream end of the liquid in the spraying step is always located at the mixing site, and the discharge amount of the liquid is constant.

According to a fifth aspect of the present invention, there is provided a coating apparatus for simultaneously supplying a liquid and a gas, mixing them at the tip of the spray nozzle, and spray-coating the substrate to be processed, wherein the liquid is supplied to the spray nozzle. A liquid supply system, a gas supply system for supplying a gas that joins the liquid supply system, and control means for controlling the operations of the liquid supply system and the gas supply system, wherein the control means is provided immediately before spray coating. By controlling the gas to be supplied from the gas supply system to the spray nozzle for a predetermined time, the gas and the liquid are simultaneously supplied to supply only the gas for a predetermined time immediately before performing the spray coating. Therefore, immediately before the spray coating is performed, the liquid is blown off by the gas on the downstream side of the gas-liquid mixing portion of the spray nozzle. Therefore, the liquid surface at the downstream end of the liquid in the spray coating is always located at the mixing portion, and the coating apparatus in which the discharge amount of the liquid is constant is provided.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram illustrating a configuration of a spray nozzle.

FIG. 3 is a time chart illustrating a method of applying a photoresist liquid according to the first embodiment.

FIG. 4 is a time chart showing a photoresist liquid applying method according to a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 suction spin chuck 5 scatter prevention cup 6 solvent supply mechanism 7 gas supply system 8 solvent (gas) supply system 11 coating liquid discharge nozzle 13 coating liquid supply section 15, 23 drive section 17 spray nozzle 17a spray gun 19 solvent supply source 19a , 21 solenoid on-off valve 31 control unit 33 memory W board

Claims (7)

[Claims] 1. A coating method in which a liquid and a gas are simultaneously supplied, mixed at a tip of a spray nozzle, and spray-coated on a substrate to be processed, wherein only a gas is supplied for a predetermined time immediately before a spray coating process. A coating method, comprising performing a spray coating process on a substrate to be processed after the process. 2. The coating method according to claim 1, wherein a processing step of discharging and discarding only a small amount of liquid is performed before the step of supplying only gas. 3. The coating method according to claim 1, wherein the liquid has volatility. 4. The coating method according to claim 1, wherein the step of supplying only the gas for a predetermined time is performed at a standby position of the spray nozzle, and supplying only the gas for a predetermined time. The spray nozzle is moved to an application position to perform a spray application step after the completion of the application step. 5. A coating apparatus for simultaneously supplying a liquid and a gas, mixing them at a tip of a spray nozzle, and spray-coating the substrate to be processed, comprising: a liquid supply system for supplying a liquid to the spray nozzle; A gas supply system that supplies a gas that joins the liquid supply system; and a control unit that controls operations of the liquid supply system and the gas supply system. The control unit is configured to perform the spray nozzle immediately before performing spray coating. A coating device for controlling only gas for a predetermined time from a gas supply system. 6. The coating apparatus according to claim 5, wherein the control means is a timing instruction means for instructing an operation timing of the liquid supply system and the gas supply system, and a signal from the timing instruction means. Discharge control means for controlling discharge of the liquid or gas from the liquid supply system and the gas supply system in accordance with the timing. An application device, wherein spray application is performed by control means. 7. The coating apparatus according to claim 5, wherein the control unit supplies only a small amount of liquid from the liquid supply system before supplying only gas from the gas supply system. A coating apparatus characterized by controlling discharge and disposal.