JP2002316080A - Apparatus for treating base board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base board treating apparatus for detecting accurately the instant that a treating liquid is discharged from a discharge nozzle. SOLUTION: A base board W is held by a spin chuck 10 to keep a horizontal posture and is rotated on the horizontal plane. A resist is discharged from the discharge nozzle 20 toward the rotating base board W. The dripped resist is spread on the whole surface of the base board W by centrifugal force so that resist application is made to proceed. At this time, the liquid discharging state detecting area near a discharge port 20a being the tip of the nozzle 20 is photographed by a camera 30. A background plate 60 is arranged to cover at least the backside of the liquid discharging state detecting area when viewed from the camera 30. The reflected picture and pattern of the base board W is prevented by the plate 60 from being photographed by the camera 30 so that noise is decreased in the photographed image and the instant that the treating liquid is discharged from the nozzle 20 can be detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the discharge of a processing liquid such as a photoresist onto a semiconductor substrate, a glass substrate for a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk, etc. (hereinafter simply referred to as a "substrate"). And a predetermined processing such as resist coating.

[0002]

2. Description of the Related Art Products such as semiconductors and liquid crystal displays are manufactured by subjecting a substrate to a series of processes such as cleaning, resist coating, exposure, development, etching, formation of an interlayer insulating film, and heat treatment. . Among these processes, the resist coating process is a rotary resist coating in which a photoresist (hereinafter simply referred to as “resist”) is dropped on a main surface of the substrate while rotating the substrate to apply the resist to the substrate surface by centrifugal force. It is often performed by a processing device (a so-called spin coater).

[0005] FIG. 5 is a diagram showing a main configuration of a conventional resist coating apparatus. The substrate W is a spin chuck 110
Is held in a substantially horizontal posture. The spin chuck 110 is rotatable by a motor (not shown), and the substrate W held by the rotation of the spin chuck 110 can be rotated in a horizontal plane.

The discharge nozzle 120 has a discharge port 1 at its tip.
From 20a, a resist is dropped on the substrate W held by the spin chuck 110 and rotated. The dropped resist spreads on the main surface by the rotation of the substrate W, and the resist coating process proceeds.

[0005] A cup 130 is arranged so as to surround the periphery of the substrate W held by the spin chuck 110. The cup 130 receives and collects the resist scattered from the rotating substrate W.

Further, a camera 1 is provided in the resist coating apparatus.
40 and lighting 150 are provided. Camera 140
Is provided with a CCD inside thereof, and discharge nozzles 120
Can be photographed in the vicinity of the discharge port 120a. Lighting 1
Reference numeral 50 illuminates the vicinity of the discharge port 120a of the discharge nozzle 120 at the time of photographing by the camera 140, and gives illuminance suitable for photographing.

[0007] Such a rotary resist coating apparatus operates according to a predetermined processing program to advance the resist coating processing. Specifically, the number of rotations of the substrate W is increased at a predetermined timing after the resist is dropped from the normal discharge nozzle 120, the resist is spread on the surface of the substrate W, and then the number of rotations of the substrate W is decreased. A uniform resist film is formed. That is, in order to form a uniform resist film, it is important to accurately grasp the timing at which the discharge nozzle 120 discharges the resist.

For this purpose, the resist coating apparatus is provided with a camera 140. The camera 140 captures the moment when the resist is discharged from the discharge nozzle 120, so that the subsequent rotation speed control of the substrate W can be accurately performed. Thus, a uniform resist film can be formed.

[0009]

However, in the above-mentioned conventional resist coating apparatus, the reflected image reflected on the main surface of the substrate W is mixed with the image captured by the camera 140, and the reflected image becomes noise. There has been a problem that the moment of resist discharge from the discharge nozzle 120 cannot be accurately detected.

FIG. 6 shows an example of an image captured by a camera 140 in a conventional resist coating apparatus. FIG. 4 is a photographed image when the resist is being discharged from the discharge nozzle 120. As shown in FIG. 6, in addition to the substantial image 121 of the discharge nozzle 120 and the substantial image 123 of the resist being discharged, an image 125 of a pattern reflected on the main surface of the substrate W
Is photographed by the camera 140.

Depending on the type of the substrate W, various patterns (for example, interference fringes) may be created by rotation, and an image 125 of such a pattern will be taken by the camera 140.

The resist coating processing apparatus performs image processing on an image captured by the camera 140 by image analysis means, and detects the moment of resist discharge from the discharge nozzle 120 by, for example, identifying the difference in shade of color. However, as shown in FIG. 6, when the pattern image 125 is mixed in the captured image, this may cause noise in image processing and hinder detection of resist ejection. Discharge nozzle 120
If it is not possible to accurately detect the moment when the resist is discharged from the substrate W, it will be difficult to accurately control the rotation speed of the substrate W thereafter, and as a result, there will be a problem that resist coating failure occurs.

The present invention has been made in view of the above problems, and has as its object to provide a substrate processing apparatus capable of accurately detecting the moment when a processing liquid is discharged from a discharge nozzle.

[0014]

According to a first aspect of the present invention, there is provided a substrate processing apparatus for performing a predetermined processing by discharging a processing liquid onto a substrate, wherein the substrate is held in a substantially horizontal posture. Holding means, a discharge nozzle for discharging the processing liquid onto the substrate held by the holding means, a photographing means for photographing a liquid discharge detection area near a discharge port of the discharge nozzle, and at least the liquid viewed from the photographing means. A background plate provided in a range covering the rear of the ejection detection area.

According to a second aspect of the present invention, in the substrate processing apparatus according to the first aspect of the present invention, there is further provided an illuminating means for irradiating the vicinity of the discharge port.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a substrate processing apparatus according to the present invention. The substrate processing apparatus 1 is a rotary resist coating apparatus (spin coater) that applies a resist by dropping a resist on a rotating substrate W. The substrate processing apparatus 1 includes a spin chuck 10 for holding a substrate W, a discharge nozzle 20 for discharging a resist onto the substrate W, a camera 3
0, illumination 40, cup 50, and background plate 60.

The spin chuck 10 holds the substrate W in a horizontal posture (the normal direction of the main surface is along the vertical direction). Although the spin chuck 10 of the present embodiment is a holding unit of a type that holds the back surface of the substrate W by vacuum suction, it may be a type that holds the edge of the substrate W.

On the lower surface of the center portion of the spin chuck 10, a rotating shaft 11 is vertically provided. The rotating shaft 11 is connected to an electric motor (not shown).
Is rotated, the spin chuck 10 and the substrate W held by the chuck are rotated in a horizontal plane.

The discharge nozzle 20 is a hollow cylindrical body which is connected to a resist supply source (not shown) so that the resist can be discharged from a discharge port 20a at the tip thereof. The discharge nozzle 20 discharges a resist near the center of the substrate W held by the spin chuck 10. By dropping the resist near the center of the rotating substrate W,
The dropped resist spreads over the entire surface of the substrate W by the rotational centrifugal force, and the resist coating process proceeds. The discharge nozzle 20 can be moved between a discharge position at which a resist is discharged by a drive mechanism (not shown) and a retract position which does not interfere with the transfer of the substrate W.

The cup 50 is disposed so as to surround the spin chuck 10 and the substrate W held thereon. The cup 50 receives and collects the resist scattered from the rotating substrate W. The cup 50 can be raised and lowered by a lifting mechanism (not shown) between a raised position (the position shown in FIG. 1) during the resist coating process and a retracted position that does not interfere with carrying in and out of the substrate W.

The camera 30 has a charge coupled device (CCD).
evice). The camera 30 may be installed at the upper end of the cup 50, or may be fixedly arranged at a portion other than the cup 50. In any case, at the time of the resist coating process, the camera 30 can photograph the liquid discharge detection area near the discharge port 20a of the discharge nozzle 20. The image signal captured by the camera 30 is transmitted to the image processing unit 35, binarized by the image processing unit 35, and the binarized image is set as a captured image. The image processing unit 35 performs predetermined image processing on the captured image and determines whether or not the resist is being discharged from the discharge port 20 a of the discharge nozzle 20. here,
The image signal transmitted to the image processing unit 35 and used for discrimination of ejection is not limited to binarization, but may be converted to another value such as ternary, quaternary, or 255-level. Good.

The result of the judgment by the image processing section 35 is transmitted to the controller 5. The controller 5 is a control unit that controls the operation of the substrate processing apparatus 1 according to a predetermined processing program. The controller 5 changes the rotation speed of the substrate W based on the point in time when the image processing unit 35 detects that the resist is being discharged from the discharge port 20 a of the discharge nozzle 20.

The illumination 40 is a light source composed of, for example, a light emitting diode. Light 40 is cup 5
0 may be installed at the upper end of the
It may be fixedly arranged at a part other than the above. In any case, during the resist coating process, the illumination 40 irradiates the vicinity of the discharge port 20a of the discharge nozzle 20. More preferably, the illumination 40 is disposed at a position where light can be applied to the entire background plate 60 described later.

The background plate 60 is fixed to the discharge nozzle 20 via a locking member 61. The background plate 60 is a plate-shaped member, and its surface faces the camera 30. Background plate 60
Is provided in a range that covers at least the rear of the liquid discharge detection area near the discharge port 20a of the discharge nozzle 20 as viewed from the camera 30. Therefore, at the time of the resist coating process, the liquid discharge detection area near the discharge port 20a of the discharge nozzle 20 with the background plate 60 as a background is reflected in the field of view of the camera 30. In the present embodiment, the liquid discharge detection area is a region indicated by a dotted line in FIG. 3 and FIG.
0a and a region including the resist discharged from the discharge port 20a and reaching the surface of the substrate W.

In this embodiment, the spin chuck 1
0 corresponds to the holding unit, the camera 30 corresponds to the photographing unit, and the illumination 40 corresponds to the illumination unit.

Next, the processing procedure of the resist coating processing in the substrate processing apparatus 1 will be briefly described. First, an unprocessed substrate W is carried in by a substrate transfer robot (not shown), and is attracted and held by the spin chuck 10. Thereafter, the cup 50 is raised to be positioned around the substrate W, and the ejection nozzle 20 is moved to
a is positioned above the center of the substrate W.

Next, the substrate W is rotated, and after the number of rotations reaches a certain number, discharge of a predetermined amount of resist from the discharge nozzle 20 is started. Then, when a predetermined time has elapsed since the resist was discharged from the discharge nozzle 20, the substrate W
Is increased, and the dropped resist is spread over the entire surface of the substrate W by centrifugal force. After the resist spreads over the entire surface of the substrate W, the rotational speed of the substrate W is reduced to form a resist film having a uniform thickness. Thereafter, the discharge nozzle 20 and the cup 50 are retracted, and the processed substrate W is carried out by the substrate transfer robot.

The control of the rotation speed of the substrate W is performed by the controller 5 of the apparatus. Specifically, camera 3
0 performs predetermined image processing on the captured image, and the image processing unit 35 detects the moment when the resist is discharged from the discharge port 20 a of the discharge nozzle 20. The controller 5 controls the electric motor to change the rotation speed.

In order to form a uniform resist film on the substrate W and obtain a good coating process result, it is important to control the number of revolutions by the controller 5 after dropping the resist on the main surface of the rotating substrate W. Become. That is, it is important to change the rotation speed of the substrate W when a certain period of time has elapsed exactly after the resist is discharged onto the substrate W. For this purpose, it is necessary for the image processing unit 35 to accurately detect the moment when the resist is discharged from the discharge nozzle 20 and to inform the controller 5 of the apparatus of the detection.

In the substrate processing apparatus 1 of the present embodiment, the background plate 60 is viewed from the camera 30 and the discharge port 20 of the discharge nozzle 20 is disposed.
It is provided in a range that covers the back of the liquid ejection detection area near a. Therefore, a captured image IM1 of the liquid discharge detection area captured by the camera 30 when the processing liquid is not discharged from the discharge nozzle 20 is as shown in FIG.

As shown in FIG. 2, when the processing liquid is not discharged from the discharge nozzle 20, the camera 30 takes an image of the liquid discharge detection area constituted only by the discharge nozzle 20 and the background plate 60, The captured image IM1 of the area includes only the substantial image 25 of the discharge nozzle 20 and the substantial image 65 of the background plate 60.

FIG. 3 shows a photographed image IM2 of the liquid discharge detection area photographed by the camera 30 while the processing liquid is being discharged from the discharge nozzle 20. As shown in FIG. 3, when the processing liquid is being discharged from the discharge nozzle 20, the camera 30 captures an image of a liquid discharge detection area constituted only by the discharge nozzle 20, the resist discharged from the discharge port 20a, and the background plate 60. That is, the photographed image IM2 of the liquid ejection detection area includes only the substantial image 25 of the ejection nozzle 20, the substantial image 29 of the resist to be ejected, and the substantial image 65 of the background plate 60.

As described above, since the entire liquid ejection detection area photographed by the camera 30 is covered by the background plate 60, the reflected image reflected by the substrate W and the pattern formed by the rotation of the substrate W can be captured by the camera. This prevents the reflected image and the image of the pattern from being included in the image captured by the camera 30 in the liquid discharge detection area.

The image processing section 35 performs conventionally known image processing such as, for example, discriminating the difference in shade of color on the image captured by the camera 30 and detects the moment when the resist is discharged from the discharge nozzle 20. More specifically, the discharge nozzle 20
At the moment when the resist is discharged from the camera, the photographed image from the camera 30 includes the real image 29 of the resist to be discharged, and the portion of the real image 29 of the resist undergoes shading change. The image processing section 35 transmits the resist to the controller 5 of the apparatus at the time when the density change occurs, as the moment when the resist is discharged from the discharge nozzle 20. Note that the image processing performed by the image processing unit 35 on the photographed image is not limited to the one that identifies the density difference of colors, and any image processing that can detect the presence or absence of resist ejection from the ejection nozzle 20 is used. Various known image processing can be adopted.

In the substrate processing apparatus 1 of the present embodiment,
Since the entire liquid ejection detection area photographed by the camera 30 is covered by the background plate 60, the photographed image is prevented from including a reflected image or a pattern image of the substrate W. As described above, such a reflection image or a pattern image of the substrate W becomes noise when performing the above-described image processing. However, as in the present embodiment, the reflection image of the substrate W appears in the captured image. If images of patterns and patterns are not included, noise during image processing is significantly reduced, image processing can be performed reliably and stably, and the moment when the resist is discharged from the discharge nozzle 20 can be accurately detected. . Then, as a result, the controller 5 can accurately control the number of rotations, and obtain a good resist coating processing result.

Further, the illumination 40 illuminates the vicinity of the discharge port 20a of the discharge nozzle 20, so that the illuminance in the vicinity of the discharge port 20a is improved. Instant can be detected more accurately.

In order to reduce noise during image processing as much as possible, it is preferable that the surface of the background plate 60 facing the camera 30 has no pattern and one color. If a pattern is drawn on the surface of the background plate 60 facing the camera 30, or if there are two or more colors, they are reflected in an image captured by the camera 30, and may cause noise during image processing. Because there is.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described example.
For example, in the above embodiment, the substrate processing apparatus 1 is an apparatus for applying a resist to the substrate W. However, application of the technology according to the present invention is not limited to the resist coating apparatus, and the processing liquid may be applied to the substrate. For example, a developing device or an apparatus for forming an interlayer insulating film may be used as long as the apparatus performs predetermined processing by discharging. In particular, it is significant to apply the technology according to the present invention to an apparatus in which it is important for the process to grasp the timing of discharging the processing liquid.

In the above embodiment, the image processing unit 35 detects the discharge of the resist by performing the image processing of the photographed image.
It is also possible to adopt a mode in which the operator visually recognizes the discharge of the processing liquid from the captured image of 0. Even in this case, since the image captured by the camera 30 does not include the image of the reflection or the image of the pattern of the substrate W, the discharge of the processing liquid from the discharge nozzle 20 can be easily visually recognized.

In the above embodiment, the background plate 6
0 is fixed to the discharge nozzle 20, but the installation of the background plate 60 is not limited to the fixation to the discharge nozzle 20, and the discharge port 20 a of the discharge nozzle 20 when the background plate 60 is viewed from the camera 30. May be provided at another position as long as it is provided at a position covering at least a range covering the rear of the liquid discharge detection area near the discharge port 20a.

In the above embodiment, the liquid discharge detection area includes the discharge port 20a of the discharge nozzle 20 as viewed from the camera 30 and the resist discharged from the discharge port 20a to reach the surface of the substrate W. However, the liquid discharge detection area is not necessarily the discharge port 20 of the discharge nozzle 20.
It is not necessary to set the region including a. FIG. 4 is a photographed image IM3 of a liquid discharge detection area taken by the camera 30 when the processing liquid is discharged from the discharge nozzle 20 in another embodiment of the present invention, and the liquid discharge detection viewed from the camera 30. As shown in FIG. 4, the area may be an area including a resist that is discharged from the discharge port 20a and reaches the surface of the substrate W.

Even in such a configuration, when the processing liquid is not being discharged from the discharge nozzle 20, the camera 30 takes an image of the liquid discharge detection area constituted only by the background plate 60. When the processing liquid is being discharged from the nozzle 20, the camera 30 captures an image IM 3 of the liquid discharge detection area shown in FIG. 4, that is, only the resist and the background plate 60 discharged from the discharge port 20 a of the discharge nozzle 20. Become. Therefore, also in this case, the same effect as that described in the above embodiment can be obtained.

[0044]

As described above, according to the first aspect of the present invention, the area covering at least the rear of the liquid ejection detection area as viewed from the photographing means for photographing the liquid ejection detection area near the discharge port of the discharge nozzle. Since the imaging device does not capture the reflected image or pattern of the substrate, the noise in the captured image is reduced, and the moment when the processing liquid is discharged from the discharge nozzle can be accurately determined. Can be detected.

According to the second aspect of the present invention, since the illumination means for irradiating the vicinity of the discharge port is further provided, the illuminance near the discharge port is improved, and the moment when the processing liquid is discharged from the discharge nozzle can be more accurately determined. Can be detected.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a substrate processing apparatus according to the present invention.

FIG. 2 is a diagram illustrating a captured image captured by a camera when a processing liquid is not being discharged from a discharge nozzle.

FIG. 3 is a diagram illustrating a captured image captured by a camera when a processing liquid is being discharged from a discharge nozzle.

FIG. 4 is a diagram illustrating a captured image captured by a camera when a processing liquid is being discharged from a discharge nozzle in another embodiment according to the present invention.

FIG. 5 is a diagram showing a main configuration of a conventional resist coating apparatus.

FIG. 6 is a view showing an example of a captured image of a camera in the conventional resist coating apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 5 Controller 10 Spin chuck 20 Discharge nozzle 20a Discharge port 30 Camera 35 Image processing unit 40 Lighting 50 Cup 60 Background plate

Continued on the front page F term (reference) 2H025 AA00 AB16 AB20 EA05 4F041 AA02 AA06 AB01 BA31 4F042 AA08 EB08 EB17 5F046 JA01 JA16

Claims (2)

[Claims] 1. A substrate processing apparatus for performing a predetermined processing by discharging a processing liquid onto a substrate, comprising: holding means for holding the substrate in a substantially horizontal posture; and applying the processing liquid to the substrate held by the holding means. A discharge nozzle for discharging, a photographing means for photographing a liquid discharge detection area near a discharge port of the discharge nozzle, and a background plate provided in a range covering at least the rear of the liquid discharge detection area when viewed from the photographing means, A substrate processing apparatus comprising: 2. The substrate processing apparatus according to claim 1, further comprising an illuminating unit that irradiates the vicinity of the discharge port.