JPH10328608A - Treatment liquid feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the continuation of improper treatment for a base by measuring the time started from the point of time of executing a feed start command, comparing the time with the specified preset time and informing defects of the treatment and starting the execution of following commands based on the feed detection of a treatment liquid by a control means. SOLUTION: Photographs of the vicinity of rotation center of a base are taken by a CCD camera 30 of an I/O control section 53 through a camera control section 52. An image signal on a base surface is binarized and stored as a stationary image in an image memory 55. The difference of light and shade of a reference stationary image is compared with those of the above stationary image stored in the image memory 55 by an image processing section 54. In the case of finding some difference generated by them, the difference represents that a photograph liquid reaches the base surface, and an arrival sensing signal is output from the image processing section 54 to a control section 20. A timer start command is executed at that point of time by the control section 20 and a built-in timer is reset and count is started, and a feed stop command is executed at the point of time when the feed time has passed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist liquid for a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, and a substrate for an optical disk (hereinafter simply referred to as a substrate). SOG solution (Spin On
The present invention relates to a processing liquid supply device for supplying a processing liquid such as a glass: silica-based film forming material) and a polyimide resin, and particularly to a technique for executing a processing program instruction based on the supply of a processing liquid.

[0002]

2. Description of the Related Art As a conventional apparatus of this type, for example, there is a photoresist liquid supply apparatus for supplying a photoresist liquid as a processing liquid to a substrate surface. This apparatus is composed of a plurality of instructions and defines a processing program (also referred to as a spin coating program) that defines a series of processes stored in advance and defines the type of photoresist liquid, the number of rotations during coating, the time thereof, and the like. Based on the above, for example, the control unit drives the substrate supported by the rotation support unit at a predetermined rotation speed by executing a rotation start command, and the control unit executes the supply start command to perform processing. The supply of the photoresist liquid to the substrate surface via the liquid supply nozzle is started. After a certain time has passed since the execution of the timer start instruction from the execution of the supply start instruction, the supply of the photoresist solution is stopped, or the substrate is rotated at a high speed so that the entire surface of the substrate has a predetermined thickness. Is formed.

[0003] When the control unit executes a supply start command, the photoresist liquid is expanded by sending pressurized air from a pressurized air source which is one of utilities provided in the clean room. An air cylinder to be operated and a bellows pump interlocked with the operation of the air cylinder are supplied to the substrate from the nozzle tip. The air cylinder is provided with a speed adjusting valve for adjusting the speed at which the pressurized air is introduced / discharged.

In addition, in addition to the above-described structure, a problem that the photoresist liquid remaining in the processing liquid supply nozzle when the supply of the photoresist liquid is stopped is dripped mainly in the vicinity of the nozzle tip end (so-called so-called nozzle). In order to prevent "dropping"), a suck-back valve is provided which works to suck the photoresist liquid remaining inside the nozzle and pull it back slightly. At the time of supply, the operation of the suck back valve is released almost simultaneously with the operation of the air cylinder. The suck-back valve that operates in this manner is also operated by introducing / discharging pressurized air from a pressurized air source, which is one of utilities.

[0005]

In the above-described apparatus, even if the supply start command is executed by the control unit, the supply of the photoresist liquid is not immediately started but is delayed. Therefore, actually, the photoresist liquid is supplied from the nozzle with a delay at least by a delay time (hereinafter, this delay time is referred to as a start delay time) from the time when the supply start command is executed by the control unit. Therefore, there is a problem that the created spin coating program cannot perform a desired process accurately.

Therefore, in order to solve such inconvenience, in a conventional apparatus, when a spin coat program is created, a photoresist liquid is actually supplied at a desired time in consideration of the start delay time in advance. To be,
The point in time at which the supply start command is executed is advanced by the start delay time (hereinafter, this is referred to as "manual delay time correction"). Specifically, for example, after the rotation start command is executed, when the rotation speed of the substrate sufficiently reaches the target rotation speed and the rotation is stabilized (this is referred to as T _S ), the photoresist liquid the when it is desired to supply from the nozzle, when the start delay time and T _DS, when creating a spin coating program which is the processing program, the supply start instruction is executed at time T _S -T _DS Program is created in advance as described above.

However, such manual delay time correction has the following disadvantages. As described above, the air cylinder and the suck-back valve related to the supply of the photoresist liquid are operated by the pressurized air source which is one of utilities provided in the clean room. This pressurized air source is usually used also in other devices in a clean room, and its pressure fluctuates delicately over time (time variation) or daily (day variation) depending on the state of use. . Therefore, since the start of the supply of the photoresist liquid is controlled using the utility that fluctuates in this way, the start delay time becomes longer or shorter with the fluctuation, and as a result, as described above, “ In the “manual delay time correction”, the above-described inconvenience cannot be sufficiently solved, and even if the processing is performed by the same processing program, the processing may not be performed uniformly.

The air cylinder and suck-back valve relating to the supply of the photoresist liquid can adjust their operation speeds. If the speeds are readjusted, the start delay time is reduced. Also fluctuates, so in the “manual delay time correction” described above,
After all, the above disadvantages cannot be sufficiently eliminated.

In particular, in the recent semiconductor manufacturing industry,
With the advancement of process miniaturization technology and the increase in the diameter of substrates, precision is required for processing, and processing programs such as spin coating programs have become very delicate and precise. Therefore, in the delay time correction related to the manual supply of the processing liquid performed in the conventional apparatus, the programming work is complicated or the programming cannot be performed at all.

In order to solve the above-mentioned problem of the "manual delay time correction", the following apparatus has been proposed. That is, a detecting means for detecting that the photoresist liquid has been supplied from the processing liquid supply nozzle is provided, and for example, it is determined whether or not the photoresist liquid is actually supplied from the time when the supply start command is executed. In some cases, the instruction is executed after the determination is made that the supply has been made.

More specifically, from the time when the supply start command is executed to the time when the photoresist liquid is actually supplied to the substrate, for example, when the photoresist liquid is discharged from the tip of the processing liquid supply nozzle Alternatively, the time when the photoresist liquid discharged from the tip of the processing liquid supply nozzle reaches the surface of the substrate is detected, and a timer start command is executed from this time. Accordingly, the execution time of the command after the supply start command can be made to depend on the time at which the photoresist liquid is actually supplied irrespective of the magnitude or fluctuation of the start delay time. Therefore, the supply time of the photoresist solution can be made constant, and the processing between each lot or within each lot can be uniformly performed.

On the other hand, on the other hand, when the photoresist liquid cannot be supplied due to a disconnection of the photoresist liquid piping or an empty processing liquid tank storing the photoresist liquid. If the detection means is in a state in which the supply of the photoresist liquid cannot be detected due to some abnormality, the state of detecting the supply of the photoresist liquid after the supply start command is executed continues. Thus, there is a problem that the processing is stopped.

Incidentally, when the photoresist solution cannot be supplied, the substrate is left rotating and left untreated, and the flow of the sequentially processed substrates is interrupted, so that the throughput is significantly reduced. In the state where the supply of the photoresist solution cannot be detected, the expensive photoresist solution is continuously supplied in vain, and the cost is wasted.

The present invention has been made in view of such circumstances, and based on the supply of the processing liquid,
Processing liquid supply that can perform uniform processing on the substrate by executing subsequent instructions, but can prevent the substrate from being continuously subjected to inappropriate processing by detecting processing defects. It is intended to provide a device.

[0015]

The present invention has the following configuration in order to achieve the above object. In other words, the processing liquid supply device according to claim 1 is composed of a plurality of instructions including a supply start instruction, and the control means controls the supply start instruction based on a processing program that prescribes a series of processes. A supply detecting means for detecting that the processing liquid is supplied from the processing liquid supply means, and a supply start instruction. And a notifying unit for notifying that a problem has occurred in the processing based on comparing the elapsed time with a predetermined time set in advance. At the same time, when sequentially executing each command included in the processing program, the control unit executes the supply start instruction to execute the supply of the processing liquid from the processing liquid supply unit. Start the feed, on the basis that the supply detecting means detects the supply of the processing solution, characterized in that to start it executing the subsequent instructions.

According to a second aspect of the present invention, in the processing liquid supply apparatus according to the first aspect, the supply detecting means includes a processing liquid ejected from the processing liquid supply means, the processing liquid being supplied to the substrate. Is detected as supply of the processing liquid.

According to a third aspect of the present invention, in the processing liquid supply apparatus according to the first aspect, the supply detecting means may be configured to “discharge” the processing liquid from the processing liquid supply means. Is detected as the supply of the processing liquid.

According to a fourth aspect of the present invention, in the processing liquid supply device according to any one of the first to third aspects, the supply detecting means is configured to supply the processing liquid based on an instruction from the control means. Photographing means for photographing the vicinity of the substrate surface including the tip of the supply means, image taking out means for taking out the photographed image as a still image, and the processing liquid `` reached '' based on the density change of the still image or `` And a density discriminating means for discriminating that the ejection has been performed as a supply of the processing liquid.

[0019]

The operation of the first aspect of the invention is as follows. When the control means executes the supply start command, the elapsed time from this point is measured by the time measuring means. After the supply start instruction is executed, the control unit starts executing each instruction after the supply start instruction based on the detection of the supply of the processing liquid from the processing liquid supply unit by the supply detection unit. The transition to a later command can be made dependent on the point in time when the processing liquid is actually dispensed. Therefore, the start delay time from the execution of the supply start instruction to the actual supply of the processing liquid and the fluctuation thereof can be absorbed, and the processing liquid supply time can be made constant.

Even if the supply start command is executed, the supply of the processing liquid cannot be detected if the processing liquid tank is empty or if there is an abnormality in the supply detecting means. Based on comparison with a specific time set in advance, the notifying unit can notify that a problem has occurred in the processing. Therefore, the operator can immediately know that a problem has occurred in the processing.

According to the second aspect of the present invention, the fact that the processing liquid discharged from the processing liquid supply means actually reaches the substrate through a gap of about several millimeters is used as the processing liquid supply. By detecting the timing and setting the time as a transition timing to a command after the supply start command, the supply time of the processing liquid can be kept constant.

According to the third aspect of the present invention, the fact that the processing liquid is "discharged" from the processing liquid supply means is detected as the supply of the processing liquid, and the time is changed to a command after the supply start command. The supply time of the processing liquid can be made constant by setting the transition timing.

According to the fourth aspect of the present invention, an image near the surface of the substrate including the leading end of the processing liquid supply unit, which is taken by the photographing unit based on an instruction from the control unit, is taken as a still image by the image taking out unit. Take out as. By determining the change in shading of the still image by the shading determining means, the point in time when the processing liquid reaches the substrate or the point in time when the processing liquid is discharged from the processing liquid supply means can be detected as the supply of the processing liquid. The control means starts execution of an instruction subsequent to the supply start instruction based on the supply time.

[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 block diagram showing a schematic configuration of a rotary substrate coating apparatus (also called a spin coater) which is an example of a processing liquid supply apparatus according to the present invention.

In the drawing, reference numeral 1 denotes a suction-type spin chuck, which suction-holds a substrate W in a substantially horizontal posture. The suction type spin chuck 1 is rotationally driven by an electric motor 3 via a rotation shaft 2, and rotates the substrate W about a rotation center P in a substantially horizontal posture. The rotation of the electric motor 3 is controlled by a control unit 20 described later.

Around the substrate W, a scattering prevention cup 4a for preventing scattering of a photoresist liquid, which is an example of a processing liquid, and a cleaning liquid for cleaning the back surface of the substrate W, is provided. In addition, in the upper opening of the scattering prevention cup 4a,
An upper lid member 4b having a plurality of openings formed therein for taking in a down flow is fixed to a frame of the apparatus, and is disposed in a fixed state. When a transport mechanism (not shown) places an unprocessed substrate W on the suction spin chuck 1 or receives a processed substrate W,
An elevating mechanism (not shown) lowers only the scatter prevention cup 4a, so that the scatter prevention cup 4a and the upper lid member 4
and the suction type spin chuck 1 is projected upward from the upper opening of the scattering prevention cup 4a. The scattering prevention cup 4a may be fixed in position, and the upper lid member 4b and the rotating shaft 2 may be raised with respect to the scattering prevention cup 4a by a lifting mechanism (not shown).

At the side of the scattering prevention cup 4a, a supply position corresponding to the position above the rotation center P on the loaded substrate W,
A processing liquid supply nozzle 5 configured to be movable from a position above the substrate W to a standby position distant from the periphery is provided. When the processing liquid supply nozzle 5 is at the supply position (the state shown by the solid line in the figure), the tip directed downward is a distance L (for example, about 4 mm, see FIG. 6) from the substrate W surface.
It is configured to be located only above. This distance L
Is adjusted so that the viscosity of the photoresist solution, the size of the substrate W, and the surface condition thereof do not cause unevenness when the photoresist solution dropped on the surface of the substrate W is spread over the entire surface. preferable.

Also, in the scattering prevention cup 4a, on the rotation center P side below the substrate W, the photoresist liquid is scattered and becomes a mist mist and adheres to the back surface of the substrate W,
A back rinse nozzle 11 is provided for ejecting a cleaning liquid toward the back surface in order to remove unnecessary photoresist solution that has flowed from the peripheral portion of the front surface of the substrate W to the back surface. The cleaning liquid from the back rinse nozzle 11 is controlled by a control unit 20 described later.

A supply pipe 12 is connected to the processing liquid supply nozzle 5, and the supply pipe 12 is connected to the suck back valve 1.
3, a bellows pump 14, and a check valve 15, which are connected to a processing liquid tank 16 storing a photoresist liquid. The suck back valve 13 is operated by sending pressurized air from a pressurized air source, which is one of utilities introduced into the clean room, and is stored inside the processing liquid supply nozzle 5 by this operation. Pull back slightly the photoresist solution
The purpose is to prevent so-called “bottling” and to prevent solidification of the photoresist liquid exposed from the ejection holes 5a. The suck-back valve 13 is deactivated by discharging the supplied pressurized air, that is, cancels the pull-back of the photoresist liquid in the processing liquid supply nozzle 5. The operation / non-operation of the suck back valve 13 is determined by the control unit 2
This is performed by an electric signal from 0. In addition, for the operation / non-operation of the suck back valve 13, the pullback pressure or the like can be adjusted. Therefore,
Depending on the degree of adjustment and the pressure of the compressed air source, the operation speed from the input of the electric signal to the withdrawal operation or the release operation of the photoresist liquid fluctuates.

The bellows pump 14 operates in conjunction with the double-acting air cylinder 17 to feed the photoresist liquid in the processing liquid tank 16 to the supply pipe 12. The check valve 15 prevents the photoresist liquid from flowing back into the processing liquid tank 16 caused by the feeding operation. The double-acting air cylinder 17 is operated by a pressurized air source via a speed control valve 18 and sends and discharges pressurized air to and from two spaces separated by a piston 17a via speed control valves 18a and 18b. Work by. The speed control valve 18 can manually adjust the pressurized air introduction speed and the pressurized air discharge speed, and the operation speed of the double-acting air cylinder 17 is adjusted by the degree of adjustment and the pressure of the pressurized air source. As a result, the operation of the bellows pump 14, that is, the speed until the photoresist liquid is supplied / stopped from the processing liquid supply nozzle 5 is adjusted. The processing liquid supply nozzle 5
, Supply pipe 12, bellows pump 14, check valve 15
A processing liquid tank 16, a double-acting air cylinder 17,
The speed control valve 18 corresponds to the processing liquid supply means of the present invention.

The speed control valve 18 is set in an operation state in which pressurized air is sent to the double-acting air cylinder 17 in response to an electric signal from the control unit 20, and is similarly set in a non-operation state in which pressurized air is discharged. The control unit 20 incorporates a clock, a timer, and a RAM (not shown) and stores in advance a “specific time” (described later) as a reference for determining whether or not a problem has occurred during processing. Time memory 21
The timer 2 measures the elapsed time from the execution of the supply start command based on an instruction from the controller 20, which will be described in detail later.
2 are connected. A RAM (not shown) stores a processing program created in advance, and the processing program is executed based on a clock and a timer. In addition, the above-described clock unit 22 corresponds to a clock unit in the present invention.

However, as will be described in detail later, after the supply start command included in the processing program for starting the supply of the photoresist liquid is executed, the "delivery detection signal" After the is input, the next instruction is executed. In addition, for example, the supply pipe 12 is disconnected, or the photoresist liquid in the processing liquid tank 16 is empty, and the photoresist liquid cannot be supplied even when the supply start command is executed. When it is determined that a failure has occurred based on a comparison between the specific time set in advance and the elapsed time measured by the timer 22, an alarm is output and the process is stopped. It has become.
The control unit 20 corresponds to the control means and the notification means of the present invention.

On the upper inner peripheral surface of the upper lid member 4b, a CCD camera 30 is disposed on the left side, and a strobe light 40 is disposed on the right side. The CCD camera 30 is composed of a CCD, which is a solid-state image sensor, an electronic shutter, and a lens. Is set to an area including a position where the substrate W is reached. In FIG. 1, the vicinity of the rotation center of the substrate W appears to be blocked by the portion of the processing liquid supply nozzle 5 extending in the horizontal direction, but the CCD camera 30 and the processing liquid supply nozzle 5 are viewed in plan. Since they are arranged laterally shifted, it is possible to take pictures near the center of rotation. Further, the strobe light 40 is used as illumination for photographing since the device itself is installed in a dark room so that the photoresist liquid is not exposed. The strobe light 40
For example, it is configured by combining a xenon lamp and a bandpass filter BPF that transmits a wavelength of 500 nm or more. The CCD camera 30 and the strobe 40 are connected to a supply detection confirmation unit 50. Also,
Instead of the xenon lamp, a high-brightness infrared light emitting diode or infrared light emitting diode array having a spectral sensitivity near an infrared wavelength and having a sufficient light emission intensity may be used as the strobe light 40. In this case, the band pass filter BPF becomes unnecessary. Further, the light source and the configuration of the strobe 40 may be appropriately selected according to the spectral sensitivity of the photoresist solution to be supplied.

The supply detection confirmation section 50 will be described with reference to FIG. The strobe 40 is supplied with required power from a strobe power supply 51 and is continuously lit. CCD
The camera 30 controls its operation, for example, the operation control of an electronic shutter that determines the photographing timing.
2 is controlled. The photographing start instruction to the camera control unit 52 is performed when a trigger signal is input from the control unit 20 to the I / O control unit 53. As will be described in detail later, the trigger signal includes a reference trigger signal for capturing a reference still image and a normal trigger signal for sequentially capturing images at a predetermined cycle.

When the reference trigger signal is input, the surface of the substrate is photographed via the CCD camera 30 at that point in time. First, an image is taken via the CCD camera 30. An image signal of the substrate surface based on the reference trigger signal captured through the CCD camera 30 is transmitted to the image processing unit 54 via the camera control unit 52 and the I / O control unit 53, where the binarization processing is performed. Then, the image data is stored in the image memory 55 as a still image (reference still image). The image signals of the substrate surface sequentially obtained based on the normal trigger signal are similarly transmitted to the image processing unit 54, binarized, and stored in the image memory 55 as a still image. Note that the strobe power supply 51 does not need to continuously supply power to the strobe 40, but supplies power only in an appropriate range including when the CCD camera 30 captures an image of the substrate surface to intermittently turn on the strobe 40. You may make it do.

The image processing unit 54 is provided with the image memory 5
5, if there is a change, it is determined that the photoresist liquid has reached the substrate W, and the “arrival detection signal” is sent to the I / O control unit 53. Is output to the control unit 20 via the. Various methods are conceivable as a method of judging the arrival based on the change in shading. For example, "1" of each binarized data is counted, and the difference between them is a certain value or more (for example, 10% or more).
Is determined to have been reached when Note that the above C
It is preferable that the field of view of the CD camera 30 is set in consideration of the processing speed required for image processing and a predetermined cycle for performing image capturing.

After the "arrival detection signal" is output to the control unit 20 via the I / O control unit 53, the still image stored in the image memory 55 is converted to the image processing unit 54 and the I / O control unit 53. And outputs a still image determined that the photoresist liquid has reached the substrate W via the monitor 59. By observing this display, the operator of the apparatus can determine whether or not the determination has been made normally. If the still image is not appropriate, the operation of the apparatus may be manually stopped by the operator. Thus, it is possible to prevent an inappropriate process from being continuously performed on all subsequent substrates.

At the time when the control unit 20 executes the supply start command, the control unit 20 stores the elapsed time from the execution time of the supply start command measured by the timer unit 22 and the specific time memory 21. It starts comparing the specific time with the predetermined period, and when the “arrival detection signal” is not output from the supply detection confirmation unit 50 until the elapsed time matches the specific time, it is determined that a problem has occurred in the processing, An “abnormal signal” is output to the supply detection confirmation unit 50 and the process is stopped. When this abnormal signal is output, the I / O control unit 53 displays "Defect occurred!" ! And the like, and a buzzer (not shown) sounds and a yellow lamp emits light. ?

The above-described CCD camera 30 and the supply detection confirming unit 50 correspond to the supply detecting unit in the present invention, the CCD camera 30 corresponds to the photographing unit, and the image processing unit 54 corresponds to the image extracting unit and the density determining unit. It is equivalent.

Next, referring to the time chart of FIG.
An example of a process of applying a photoresist liquid to the substrate W by the apparatus configured as described above will be described. In addition,
In the following description, it is assumed that the substrate W to be processed is already suction-held on the suction spin chuck 1 by a substrate transport mechanism (not shown). Further, the processing liquid supply nozzle 5 has already been moved to the supply position (the state shown by the solid line in FIG. 1) by the nozzle moving mechanism 10, and the discharge hole 5a has a distance L approximately above the rotation center P of the substrate W. And located.

As a method of supplying the photoresist solution, the "dynamic method" in which the supply is started while the substrate is rotating and the supply is completed in that state, and the supply is started in a state where the substrate is stationary, With the "static method", which completes the supply in that state, and with the substrate stationary, supply starts,
There is a “Stamic method” that combines the dynamic method and the static method in which the supply is completed after the substrate is started to be rotated, but here, the application processing by a processing program that uses the dynamic method is taken as an example. explain. As a matter of course, even in the static method and the static method, the same effects as described below can be obtained only with a different supply timing.

The basic flow of the coating process by this processing program (spin coat program) is as follows.

First, according to the rotation start command, the substrate W is rotated at the rotation speed R1 (for example, 1,000 rpm) at time t ₁ .
At the time T _S , the supply start command is executed, the supply of the photoresist liquid is started at a constant flow rate, and the measurement of the elapsed time is started by the timer 22 (start of timing). . Then, at time t ₂ the photoresist solution has detected that it has reached the surface of the substrate W, the timer start command for counting the time elapsed from the time t ₂ is executed, it the time is the supply time T _SU At this time (time T _E ), a supply stop command is executed to stop the supply of the photoresist solution. By rotating increase instruction is executed to the time t _5, time t
_At the time point of ₆ , the substrate W is rotated at the rotation speed R2 (for example, 3,000 r
pm), the rotation stop command is executed at time t ₈ , and the coating process is completed at time t ₉ .

During the above coating process, the photoresist liquid scatters from the periphery of the substrate W to form a mist and adheres to the back surface of the substrate W, or from the periphery of the substrate W to the back surface. In order to remove the photoresist liquid that has sneaked and adhered, it is preferable to add an instruction to eject the cleaning liquid from the back rinse nozzle 11 shown in FIG.

Further, the above-mentioned processing program executes
From the time t ₁ the rotational speed reaches R1 of, until execution time T _S of the supply start instruction to start the supply of the photoresist solution, so as to photograph the reference still image to the I / O control unit 53 A reference trigger signal output command for outputting a reference trigger signal for instructing is executed at time T _P , and at the same time as the above-mentioned supply start command is executed at time T _S , I / O control is performed. A normal trigger signal output command for outputting a normal trigger signal for instructing the unit 53 to capture a still image of the surface of the substrate W at a predetermined cycle is executed.

[0046] First, when the reference trigger signal output command is executed at time T _P, the supply detection confirmation unit 50 operates as shown in the flowchart of FIG.

Step S1 (Shooting of the substrate surface) The I / O control unit 53
The surface of the substrate W near the center of rotation is photographed by the camera 30. This image signal is transmitted to the image processing unit 54 via the I / O control unit 53.

Step S2 (Binarization Processing) The image signal transmitted to the image processing section 54 is subjected to a binarization processing by an appropriate technique to form a still image. For example, a portion where the reflectance of the surface of the substrate W is high, that is, a portion (white area) where the luminance level of the image signal exceeds a certain value is set to “0”, and a part where the luminance level is lower (black area) is set to “0”. 1 ".

Step S3 (Stored as Reference Still Image) The binarized still image is stored in the image memory 55 as a reference still image. Since this reference still image is a reference to be compared with a still image captured later,
It is preferable that the substrate W has a specific rotation angle in synchronization with the rotation control of the electric motor 3, and images of the substrate in the same posture as viewed from the CCD camera 30 are taken. Generally, a minute step is formed on the surface of the substrate W through various processes, and depending on the rotation angle of the substrate, the irradiation light from the strobe light 40 is irregularly reflected by the step and the binarization process is performed. May be set to "1". Therefore, even when a still image to be described later is photographed, a still image having the same rotation angle as the reference still image can be obtained by photographing the surface of the substrate W at the specific rotation angle. Can be prevented from being detected.

When the supply start command is executed at time T _S , the photoresist liquid starts to be supplied to the substrate W as follows. Simultaneously with the execution of the supply start instruction,
It instructs the timer unit 22 to start measuring the elapsed time, and starts comparing the specific time in the specific time memory 21 with the elapsed time at a predetermined cycle.

First, the suck-back valve 13 is set to the non-operating state, the suction in the processing liquid supply nozzle 5 is released, one of the speed control valves 18 is set to the non-operating state, and the other 18b is set to the operating state. Is done. As a result, the double-acting air cylinder 17 is brought into an operating state, and the bellows pump 14 is operated in conjunction therewith, so that a certain amount of the photoresist liquid is fed into the supply pipe 12 from the processing liquid tank 16. Through this series of operations, the photoresist liquid starts to be supplied to the surface of the substrate W from the discharge hole 5a of the processing liquid supply nozzle 5, and the one 18a and the other 18b of the speed control valve 18
The state (non-operation / operation) is alternately switched and performed once each time, whereby the piston 17a of the air cylinder 17 is raised / lowered to drive the bellows pump 14 each time, and a predetermined amount of photoresist liquid is processed. The liquid is supplied to the substrate W from the liquid supply nozzle 5. The photoresist liquid is supplied by operating each part sequentially after the supply start command is executed in this manner, and the discharge hole 5a of the processing liquid supply nozzle 5 is located above the substrate W surface. To distance L
At a time T when the supply start instruction is executed.
_{In S} , the photoresist liquid does not reach the surface of the substrate W, but actually arrives at the surface of the substrate W with a certain start delay time. The start delay time varies depending on the use status of the pressurized air source. Here, the start delay time will be described as _TDS1 .

At the same time as executing the above-described supply start instruction, the control unit 20 executes an ordinary trigger signal output instruction. When this command is executed, a normal trigger signal is output to the I / O control unit 53 of the supply detection confirmation unit 50. The I / O control unit 53 that has detected the normal trigger signal is
Is instructed to sequentially photograph the surface of the substrate W at a predetermined cycle. It is preferable that the predetermined cycle is sufficiently shorter than the start delay time T _DS1 , for example,
1 when the start delay time T _DS1 is 100 msec
It is about 0 msec. Further, the control unit 20 is set in an execution prohibited state in which the execution of the next instruction of the processing program is restricted after the execution of the supply start instruction and the normal trigger signal output instruction. 5
The state is maintained from 0 until input.

The operation of the supply detection confirmation unit 50 based on the normal trigger signal output command will be described with reference to the flowchart of FIG.

Step T1 (Shooting of substrate surface) The I / O control unit 53
The vicinity of the rotation center of the substrate W is photographed by the camera 30. This photographing timing is preferably the same as the photographing timing of the reference still image for the reason described above.

Step T2 (Binarization processing) The image signal on the surface of the substrate W is binarized by the image processing section 54 as described above.

Step T3 (Stored as Still Image) The binarized image signal is stored in the image memory 55 as a still image. Therefore, at this point, the reference still image and the still image are stored in the image memory 55. Since the still images sequentially shot thereafter are replaced with the still images in the image memory 55, the storage capacity of the image memory 55 only needs to be able to store at least the two images.

Step T4 (Comparison of Reference Still Image and Still Image) The image processing section 54 compares the reference still image stored in the image memory 55 with the still image. Specifically, the difference in the density of the two images is compared. There are various methods for comparing the shading of these binarized images. For example, there is a method of counting “1” of each of the reference still image and the still image and comparing them. Can be If the difference between the count values of "1" becomes a certain value or more (for example, 10% or more), it is determined that the density has changed, that is, the photoresist liquid has reached the surface of the substrate W. .

Step T5 (Change to Shading?) The processing branches based on the comparison result of the shading change in the image processing section 54. If there is a change, it indicates that the photoresist liquid has reached the surface of the substrate W, and the process proceeds to the next step T7. If there is no change, it indicates that the photoresist liquid has not reached the surface of the substrate W.
Take a picture of the surface.

However, when the photoresist liquid is applied to the substrate W
It is not known whether the delay is caused by the mechanism related to the supply of the photoresist liquid or the defect of the processing described above. At T6, it is determined whether or not a processing defect is the cause. Note that the above-described predetermined cycle for photographing is defined as the above-described steps T1 to T6.
Corresponds to the execution cycle.

Here, as a result of repeatedly executing step T1 to step T6, as shown in FIG. 3, the time after the elapse of the start delay time T _DS1 shorter than the specific time ST from the execution time T _S of the supply start command, as shown in FIG. determination in step T5 at t ₂ will be described when it becomes that there is change shades. The specific time ST is, for example, about 3 seconds, and is preferably set in consideration of the start delay time T _DS1 and its variation.

Step T7 (Output of arrival detection signal and still image) The image processing unit 54 outputs an "arrival detection signal" to the control unit 20 via the I / O control unit 53, and the image processing unit 54 Take out a still image from the memory 55 and I / O
Output to the monitor 59 via the control unit 53.

The control unit 20 to which the “arrival detection signal” has been input
Causes counting to be started with the reset of the internal timer running timer start command at the time t _2,
Executing the supply stop instruction at the time T _E the supply time T _SU has elapsed. In this case, the supply of the photoresist solution is stopped as follows.

First, by switching the operation / non-operation state of the two speed control valves 18a and 18b and stopping the operation to be repeated alternately, the double-acting air cylinder 17 is brought into the non-operation state and the bellows pump 14 The supply of the photoresist liquid is stopped, and the suck back valve 13 is set in the operating state, so that the photoresist liquid in the processing liquid supply nozzle 5 is slightly pulled back from the tip. With this operation, the supply of the photoresist liquid from the processing liquid tank 16 through the supply pipe 12 and the processing liquid supply nozzle 5 is stopped.
As described above, when supplying the photoresist liquid,
A start delay time T _DS1 occurs from the execution time T _S of the supply start command. In the case of the supply stop command, the photoresist liquid is transferred to the substrate W at the time when the two speed control valves 18a and 18b are in the non-operating state. since the supply of is interrupted, delayed at this time is of a degree that can sufficiently negligible compared to the start delay time T _{DS 1.}

As described above, based on the fact that the photoresist liquid has reached the substrate W, the timer start command, which is the command following the supply start command, is executed, so that the execution timing of the commands after the supply start command is adjusted. It can depend on when the photoresist liquid reaches the substrate W. Therefore, the start delay time T _DS1 from when the supply start command is executed to when the photoresist liquid actually reaches the substrate W can be absorbed, and the photoresist liquid supply time T _SU can be made constant. .

In addition to outputting the "arrival detection signal", a still image is taken out and output to the monitor 59 via the I / O control unit 53, and the still image is confirmed by the operator of the apparatus. It can be determined whether the image determined to be appropriate is appropriate. For example, the upper lid member 4
"Arrival detection signal" is output even though the photoresist liquid has not reached the substrate due to mist adhering to the lens surface of the CCD camera 30 disposed on the upper inner peripheral surface of b. Can be easily found. If such an inconvenience is found, the operator manually stops the apparatus, thereby preventing improper processing from being performed on the substrates to be sequentially processed.

Next, the case where the processing of the substrate W is completed and the processing of a new substrate W is performed will be described. At the time of processing the substrate W, the time T when the supply start command is executed is set.
_{Although the} photoresist liquid arrives at the substrate with a delay of time T _DS1 from _S, when processing a new substrate W, for example, the utilization of the pressurized air source increases in other apparatuses, and the pressure fluctuates (decreases). A description will be given on the assumption that the start delay time is longer than the start delay time T _{DS1 and} becomes the start delay time T _DS2 (see FIG. 3). However,
The start delay time T _{DS2 is} also shorter than the specific time ST. In FIG. 3, parentheses and dotted arrows indicate portions where the execution timing of an instruction differs from that of the previous substrate processing when processing a new substrate W described below.

In such a case, the execution time T _S of the supply start command is the same as in the previous substrate processing, but the start delay time is long (T _DS2 > T _DS1 ). The signal is input to the control unit 20 at a time (t ₃ ) delayed by the start delay time T _DS2 . Along with this, the timer start command is also delayed, so that the execution point (T _E ) of the supply stop command is also delayed. As a result, the time interval from the point in time when the “arrival detection signal” is input (t ₃ ) to the point in time when the supply stop command is executed (T _E ) is set to the same supply time (T _SU ) as in the previous substrate processing. can do. In other words, the photoresist liquid is supplied to the substrate W from the processing liquid supply nozzle 5 at a constant flow rate. Since the supply time T _SU is fixed, the photoresist liquid supplied to each substrate is The amounts can be the same. As a result, even if the start delay time caused by the pressure fluctuation of the pressurized air source fluctuates while sequentially processing a plurality of substrates, the fluctuation can be absorbed and the supply time can be kept constant. can do. Further, for example, even when the operation speed of the speed control valve 18 is adjusted, the fluctuation of the start delay time caused by the adjustment can be absorbed.

As described above, as the execution stop time (T _E ) of the supply stop instruction is delayed, each instruction executed thereafter is also delayed. Specifically, the execution of the rotation increase command with delayed from t ₅ to t _6, will be delayed from the rotation stop instruction is also t ₈ to t _9. As a result, the time until the supply of the photoresist solution is stopped and the rotation is increased can be made the same, and the process of spreading the photoresist solution supplied at the rotation speed R1 over the entire surface of the substrate W can be performed in the same manner. The processing can be performed for a long time, and the time from when the rotation speed is increased to the rotation speed R2 to when the rotation is stopped can be made the same, and the surplus photoresist liquid spread over the entire surface of the substrate W is shaken off. For the same time. As a result, the thickness of the photoresist film formed on each substrate can be made uniform. In addition, processing can be performed uniformly between lots or within each lot, and processing can be performed stably over a long period of time.

Next, the photoresist liquid is not supplied from the processing liquid supply nozzle 5 even if the supply start command is executed because the pipe 12 is disconnected or the processing liquid tank 16 is empty. A description will be given of a case where a processing defect occurs, such as a case where the mounting position is shifted and the field of view is off the surface of the substrate W. When such a problem occurs in the processing, no gradation change occurs in the image even if steps T1 to T6 are repeatedly executed, so that the specific time ST matches the elapsed time in step T6. .

For example, if the start delay time T _DS2 is _equal to the specific time S
T (T _S ~t ₄₎ is longer than when in excess of t ₄ time points in the time chart of FIG. 3, while Yuku Repeat steps T1 to step T6 described above, before the shading change occurs In step T6, the elapsed time matches the specific time ST. Then, the control unit 20 outputs an “abnormal signal” to the supply detection confirmation unit 50, and stops the imaging of the substrate surface.

Step T8 (Alarm output) The I / O control unit 53, which has detected the "abnormal signal" from the control unit 20, displays a message indicating that a processing failure has occurred on the monitor 59 and outputs an alarm. I do.

Step T9 (Process Stop) The control unit 20 executes a stop process such as stopping the rotation drive of the electric motor 3 and stopping the operation of the bellows pump 14 together with the output of the "abnormal signal".

As a result, the execution of the next instruction is restricted until the supply start instruction is executed and the arrival detection signal is output, as shown by the two-dot chain line in FIG.
Without supplying the photoresist liquid, the substrate W is continuously rotated at the rotation speed R1, or the photoresist liquid is supplied, and the supply of the photoresist liquid is continued even though the supply time T _SU has elapsed. It is possible to prevent inappropriate processing such as continuing rotation at the rotation speed R1 from continuing.

The operator can know that some trouble has occurred by looking at the alarm output in step T8, so that the operator only needs to inspect the stopped device, repair the trouble, and execute the process again. .

In the above-described apparatus, an image photographed by the CCD camera 30 is used for detecting the arrival of the photoresist solution. However, the image may be detected by using a sensor as described below. FIG. 6 shows this modification.
This will be described with reference to FIG.

An arrival detection sensor 6 is attached to a downwardly directed tip portion of the processing liquid supply nozzle 5. The arrival detection sensor 6 is provided with a light emitter 6 attached to a tip portion of the processing liquid supply nozzle 5 via an attachment member 6a.
b and the light receiver 6c. Each of the light projecting unit and the light receiving unit is directed to the rotation center P on the surface of the substrate W, and the irradiation light in the infrared wavelength region emitted from the light projector 6b is reflected near the rotation center P on the surface of the substrate W. The light is incident on a light receiver 6c having a light receiving element having sensitivity near the infrared wavelength region. In this example, since the detection signal of the arrival detection sensor 6 is set to be ON when light enters, the photoresist liquid is discharged from the discharge hole 5a of the processing liquid supply nozzle 5, and the substrate liquid passes through the distance L. When it reaches the surface of W, the detection signal is turned off and output to the control unit 20 as an “arrival detection signal”. Note that the arrival detection sensor 6 corresponds to a supply detection unit in the present invention.

In the case of such a configuration, the operation is performed as shown in the flowchart of FIG. That is, step U1
, It is determined whether or not the instruction is a supply start instruction, and if not, the instruction is executed (step U2). The command executed here is, for example, a rotation start command. On the other hand, if the instruction is a supply start instruction, the supply start instruction is executed in step U3, and the timer unit 22 is instructed to start timing.
Thereafter, in step U4, the arrival detection sensor 6 is turned off, that is, until the “arrival detection signal” is output from the arrival detection sensor 6 to the control unit 20 or the elapsed time matches the specific time ST. Steps U4 and U5 are repeatedly executed to regulate the execution of the next instruction.

If it is determined in step U4 that the arrival detection sensor 6 is off, the flow shifts to step U6 to execute the next command. On the other hand, if the elapsed time matches the specific time ST in step U5, an alarm is output in step U7, and the process proceeds to step T8.
The processing is stopped at. Even with such a relatively simple configuration, it is possible to obtain substantially the same effects as those of the above-described configuration.

In the above description, the process in which the photoresist liquid is ejected from the processing liquid supply nozzle 5 and reaches the surface of the substrate is treated as the supply of the photoresist liquid. Discharge hole 5a of supply nozzle 5
The "discharge" of the photoresist liquid from may be treated as the supply of the photoresist liquid.

That is, in the method of detecting the supply of the photoresist liquid using the above-described CCD camera 30, the range including the discharge hole 5a of the processing liquid supply nozzle 5 may be set as the field of view for the photographing. In this case, "arrival" in the time chart of FIG. 3 described above may be replaced with "ejection", and the same effect can be obtained.

Further, the supply of the photoresist liquid may be detected by using an ejection detection sensor 7 (supply detecting means) as shown in FIG. 8 without using the CCD camera 30.

That is, the discharge detection sensor 7 is composed of a light projecting device 7b and a light receiving device 7c attached to the distal end portion of the processing liquid supply nozzle 5 via an attaching member 7a. Each of the light projecting unit and the light receiving unit is provided so as to face each other with the processing liquid supply nozzle 5 as a center, and the irradiation light in the infrared wavelength region irradiated from the light projector 7b has a sensitivity near the infrared wavelength region. Is incident on the photodetector 7c incorporating the. In this example, since the detection signal of the discharge detection sensor 7 is set to be turned on when light enters, the detection signal is output at the time when the photoresist liquid is discharged from the discharge hole 5a of the processing liquid supply nozzle 5. In a state where the discharge is turned off and the discharge of the photoresist liquid from the discharge holes 5a of the processing liquid supply nozzle 5 is stopped, the detection signal is turned on.

As described above, a coating method suitable for a rotary substrate coating apparatus which can perform processing uniformly, but can detect a defect in the processing and prevent inappropriate processing from continuing can be mentioned. And JP-A-9-7930.

That is, the rotation speed of the substrate W is increased before the photoresist liquid which is supplied to the substrate W and spreads by centrifugal force reaches the peripheral portion of the substrate W. By applying the acceleration at such an accurate timing, the amount of the scattered photoresist liquid can be extremely reduced, but it is necessary to make the acceleration timing accurate. Therefore, when the method is applied to the apparatus according to the present invention, the acceleration timing can be accurately controlled, the processing can be made uniform, and the above-described processing problem occurs, and the photoresist liquid is supplied unnecessarily. It can be prevented from being continued.

It is needless to say that the processing liquid may be not only the above-described photoresist liquid, but also an SOG (Spin On Glass) liquid used for surface protection and insulation, and a polyimide resin. .

[0086]

As is apparent from the above description, according to the first aspect of the present invention, after the supply start command is executed, the subsequent commands are executed based on the fact that the processing liquid is actually supplied. , The transition to the next instruction can be made dependent on the point in time when the processing liquid is actually supplied.
Therefore, the start delay time related to the supply of the processing liquid and the fluctuation thereof can be absorbed, and the supply time of the processing liquid can be made constant. As a result, all processes between lots and within each lot can be uniformly performed, and the processes can be performed stably for a long period of time.

Further, based on the comparison between the elapsed time by the clocking means and the specific time set in advance, the notifying means notifies that the processing has a problem. Can be instantly known. Therefore, it is possible to prevent the inappropriate processing caused by the occurring trouble from being continuously performed.

According to the second aspect of the present invention,
Even when the "reached" is detected as the supply of the processing liquid, the supply time of the processing liquid can be kept constant.

According to the third aspect of the present invention,
Even if the "discharge" is detected as the supply of the processing liquid, the supply time of the processing liquid can be kept constant.

According to the fourth aspect of the present invention, it is possible to detect that the processing liquid has been supplied by judging a change in the density of the still image. Therefore, as compared with the supply detecting means constituted by an optical sensor or the like, it is possible to reduce the adverse effect caused by irregular reflection or disturbance light, and it is possible to detect the supply of the processing liquid with high reliability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a rotary substrate coating apparatus which is an example of a processing liquid supply apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a supply detection confirmation unit.

FIG. 3 is a time chart illustrating an example of a coating process.

FIG. 4 is a follow chart showing processing when a reference trigger signal is output.

FIG. 5 is a flowchart illustrating a process when a normal trigger signal is output.

FIG. 6 is a diagram showing an arrival detection sensor.

FIG. 7 is a flowchart illustrating a process when an arrival detection sensor is employed.

FIG. 8 is a diagram illustrating an ejection detection sensor.

[Explanation of symbols]

 W: substrate 1: suction-type spin chuck 5: processing liquid supply nozzle (processing liquid supply means) 14: bellows pump (processing liquid supply means) 17: cylinder (processing liquid supply means) 18: speed control valve (processing liquid supply means) Reference numeral 20: control unit (control means, notification means) 21: specific time memory 22: clock unit (time measurement means) 30: CCD camera (photographing means, supply detection means) 40: strobe 50: supply detection confirmation unit (supply detection means) ) 54 image processing unit (image extraction means, density discrimination means) 59 monitor

Claims (4)

[Claims] 1. A processing liquid supply unit comprising a plurality of instructions including a supply start instruction, wherein the control unit executes the supply start instruction based on a processing program that prescribes a series of processing stored in advance. A processing liquid supply device for supplying a processing liquid from the processing liquid supply means to the substrate; and a supply detecting means for detecting that the processing liquid has been supplied from the processing liquid supply means; And a notifying means for notifying that a problem has occurred in the processing based on comparing the elapsed time with a predetermined time set in advance. When sequentially executing the respective instructions included in the program, the supply of the processing liquid is started from the processing liquid supply unit by executing the supply start instruction,
The processing liquid supply apparatus according to claim 1, wherein after the supply detecting means detects the supply of the processing liquid, execution of a subsequent command is started. 2. The processing liquid supply device according to claim 1, wherein the supply detection unit detects that the processing liquid discharged from the processing liquid supply unit has reached the substrate as the supply of the processing liquid. A processing liquid supply device. 3. The processing liquid supply device according to claim 1, wherein the supply detection unit detects that the processing liquid is “discharged” from the processing liquid supply unit as a supply of the processing liquid. A processing liquid supply device characterized by the above-mentioned. 4. The processing liquid supply device according to claim 1, wherein the supply detection unit captures an image of a vicinity of a substrate surface including a front end of the processing liquid supply unit based on an instruction of the control unit. A photographing means for performing the operation, an image taking-out means for taking out the photographed image as a still image, and judging that the processing liquid has reached or been ejected as supply of the processing liquid based on a change in density of the still image. A processing liquid supply device comprising: