JPH10301301A - Gap window position detection method - Google Patents

Abstract

(57) Abstract: To automatically perform high-speed alignment between a gap window provided in a mask and a gap detector. SOLUTION: A plurality of relative positioning positions on an XY plane between a mask and a gap detector are designated, and the type of waveform at each positioning position detected by the gap detector is a gap detection waveform or a gap non-detection waveform. Based on the detected waveform, the range of the gap window is grasped. The center position is specified based on the range of the gap window grasped in this way, and the gap detector is positioned there.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proximity exposure apparatus for forming a pattern on a glass substrate in a process of manufacturing a liquid crystal display, and more particularly to a proximity exposure apparatus for automatically detecting a position of a gap window provided in a mask. The present invention relates to a gap window position detection method for an exposure apparatus.

[0002]

2. Description of the Related Art A liquid crystal display (LCD: Liqui)
d Crystal Display) is a CRT (C
Since it can be made thinner and lighter than an Anode Ray Tube, a CTV (Color Tele Tube) can be used.
vision) and OA equipment, etc., and the screen size is increased to 10 inches or more.
Higher definition and color are also being promoted. Liquid crystal displays are made by drawing a fine pattern on the surface of a glass substrate by photolithography. The exposure apparatus draws this fine pattern on a glass substrate. As this exposure apparatus, there are a projection system in which a mask pattern is projected onto a glass substrate using a lens or a mirror, and a proximity system in which a mask pattern is transferred by providing a minute gap between the mask and the glass substrate. . Although the proximity type exposure apparatus has poor pattern resolution performance compared to the projection type, the irradiation optical system is very simple, the throughput is high, and the cost performance is excellent in terms of the equipment cost. It is suitable for high-volume production equipment.

[0003]

In a proximity type exposure apparatus, positioning control of the glass substrate, that is, so-called proximity gap control is performed so that the distance between the mask and the glass substrate becomes a minute gap (separation gap). I have. Speeding up the proximity gap control is an important issue in improving the throughput of the exposure apparatus. This proximity gap control is performed by a gap detector including an LED and a CCD linear image sensor. That is, the proximity gap control performs the alignment between the four gap detectors provided on the upper surface side of the mask and the four gap windows provided on the mask, respectively. At the time, LE of the gap detector
By irradiating D light, two reflected lights reflected from the lower surface of the mask and the surface of the glass substrate are detected by a CCD linear image sensor, and the distance between the two reflected lights is measured. The gap is detected, and the glass substrate is driven and controlled in the Z-axis direction by three tilt drive motors provided on the exposure chuck so that the specified gap amount is obtained. However, conventionally, the optimum alignment between the gap window provided in the mask and the gap detector is manually performed every time the mask is replaced,
I had registered. SUMMARY OF THE INVENTION It is an object of the present invention to provide a gap window position detecting method of a proximity exposure apparatus which can automatically perform high-speed alignment between a gap window provided on a mask and a gap detector.

[0004]

A gap window position detecting method according to the present invention is directed to a gap window position detecting method for automatically detecting the position of a gap window provided in an exposure mask using a gap detector. Specifying a plurality of relative positioning positions on the XY plane between the mask and the gap detector, and determining the gap window based on the type of each waveform at the positioning position detected by the gap detector. Is detected. Four gap windows are provided at predetermined positions on the mask, and gap detectors are also provided at positions corresponding to these gap windows. Therefore, even when the mask is exchanged, the relative positional relationship between the gap window and the gap detector is almost adjacent. However, the gap detector is not always accurately positioned at the center of the gap window. The gap detector irradiates a light beam to the glass substrate from the gap window, and measures the gap between the glass substrate and the mask based on the reflected light. It is important that is positioned. When the pattern of the reflected light detected by the gap detector has two peaks, the gap can be detected using the gap window. Such a waveform having two peaks is called a gap window detection waveform. Detection of such a waveform having two peaks means that the gap detector is located near the center of the gap window.
When the pattern of the reflected light has one peak, it means that the gap detector is not located substantially at the center of the gap window. Such a waveform having one peak is referred to as a gap window undetected waveform. Therefore, a plurality of relative positioning positions on the XY plane between the mask and the gap detector are designated, and the type of waveform at each positioning position detected by the gap detector is a gap detection waveform or a gap non-detection waveform. Based on something, I tried to grasp the range of the gap window. Accurate gap detection can be performed by specifying the center position of the gap window based on the grasped range of the gap window and positioning the gap detector there.

[0005]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a diagram showing a schematic configuration of a proximity exposure apparatus relating to a gap window position detecting method according to the present invention, and FIG. 2 (A) is an AA of FIG. 2 (B).
FIG. 2B is a cross-sectional view taken along a line, and FIG. 2B is a top view in which a part of FIG. 2A is omitted. As shown in FIG. 2, a glass substrate 1 is held by suction on an exposure chuck 2. The exposure chuck 2 is driven and controlled in the Z-axis direction by a three-point contact type tilt drive motor (not shown). The mask 3 is suction-held from below by a suction-type mask holder 4 provided over the entire outer periphery. In this embodiment, the shape of the mask 3 is rectangular, and the mask holder 4 is arranged along the outer periphery of the rectangle. The exposure chuck 2 has a shape facing the inner wall surface of the mask holder 4, that is, a rectangular shape. The glass substrate 1 is also rectangular. Although the drawing shows the case where the exposure chuck 2 is larger than the glass substrate 1, it goes without saying that the glass substrate 1 may be larger. At four corners of the mask 3, rectangular gap windows 5a to 8a are provided. The gap windows 5a to 8a are portions where the pattern chrome of the mask 3 does not exist. On the upper surface side of the mask 3, gap detectors 5 and 6 provided corresponding to the gap windows 5 a and 6 a, and both of them based on reflected light from an alignment pattern provided on the mask 3 and the glass substrate 1. A rear-side detection optical system 9R having an alignment detector for performing alignment (high-precision alignment); and gap detectors 7 and 8 provided corresponding to the gap windows 7a and 8a.
And a front-side detection optical system 9F having an alignment detector for performing alignment (high-precision alignment) of the two based on reflected light from an alignment pattern provided on the mask 3 and the glass substrate 1. Since the configurations of the gap detectors 5 to 8 are all the same, the configuration of the gap detector 5 will be described. The gap detector 5 is L
An ED 51 and a CCD linear image sensor 52 are configured. The LED 51 irradiates a light beam onto the glass substrate 1 through a gap window 5 a provided in the mask 3. Then, the light beam irradiated on the glass substrate 1 is reflected on the surface thereof, passes through the gap window 5a again, and enters the CCD linear image sensor 52. Light rays reflected on the lower surface side of the mask 3 also enter the CCD linear image sensor 52. Accordingly, FIG.
A gap window detection waveform having two peaks as shown in FIG. By measuring the distance between the peaks of the output waveform, the gap between the glass substrate surface 1 and the lower surface of the mask 3 can be measured. The gap detectors 5 to 8 respectively measure the four gaps between the lower surface of the mask 3 and the surface of the glass substrate 1, calculate the correction amounts thereof by calculation, and operate the three-point tilt drive motor to operate the respective gaps. Proximity gap control is performed so that is equal to the specified gap amount. After the proximity gap control is completed, alignment between the mask 3 and the glass substrate 1 is performed using an alignment detector. The alignment is controlled by detecting an alignment pattern provided on the mask 3 and the glass substrate 1 with an alignment detector, and driving and controlling an XY, θ table (not shown) based on the alignment pattern. The alignment detector irradiates the mask 3 and the glass substrate 1 with a light beam from the light emitter 10 for epi-illumination via the half mirror 11 and the objective lens 12. The reflected light from the alignment patterns provided at two places on each of the mask 3 and the glass substrate 1 is simultaneously captured via the objective lens 12. The captured reflected light, that is, the alignment pattern is incident on the half mirror 14 via the half mirror 11 and the collimator lens 13. The half mirror 14
The reflected light is decomposed in two directions. Cylindrical lens 15
And 16 compress the reflected light and take it into the respective CCD linear image sensors 17 and 18. The amount of deviation of the alignment pattern is calculated based on the detection waveforms from the CCD linear image sensors 17 and 18, and XY, θ
The table is driven to perform alignment control between the mask 3 and the glass substrate 1. However, the gap detector 5
If the positioning of the gap windows 5a to 8a and the gap windows 5a to 8a are not performed accurately, the peak shown in FIG. 3A becomes one gap window undetected waveform, and the proximity gap control cannot be performed. Alternatively, it is difficult to perform alignment control. Before performing the proximity gap control, it is necessary to perform alignment between the gap windows 5a to 8a and the gap detectors 5 to 8. Therefore, in the present invention, the position of the gap window is accurately detected based on the difference between the gap window undetected waveform and the gap window detected waveform as shown in FIGS.
Hereinafter, a method of detecting the gap window position will be described with reference to FIG. In FIG. 1, the positions AA to AZ shown together with the left gap window 5a are the gap windows 5a.
3 shows a relative positional relationship of the gap detector 5 with respect to a. 1 and the cross mark shown together with the gap window 5a on the right side of FIG. 1 indicate whether the waveform detected by the Gaya detector 5 at each of the positions AA to AZ shown on the left side of FIG. This indicates whether the waveform is a window undetected waveform, and is shown corresponding to each of the positions AA to AZ. Therefore, when the gap detector 5 is in the position A
In the case of A to AI, a gap window detection waveform can be obtained, and therefore, it is indicated by a circle. On the other hand, the gap detector 5
Are in the positions AJ to AZ, there is a gap window undetected waveform. In FIG. 1, position A
A indicates that the gap detector 5 has been positioned at the position AA just in the middle of the gap window 5a by the first positioning process. The gap window position detecting device of the present invention sequentially changes the position of the gap detector 5 spirally from the position AB to the position AZ with reference to the position AA. The approximate position of the gap window 5a is detected in accordance with whether the waveform detected from 5 is a gap window undetected waveform or a gap window detected waveform, and the gap detector 5 is positioned at the center of the gap window 5a based on the detected position. To work. First,
When the gap detector 5 is located at the position AA, FIG.
As shown in (A), the light emitted from the LED 51 passes through the gap window of the mask 3, is reflected near the position AA on the glass substrate, and is taken into the CCD linear image sensor 52. Also, the light reflected on the lower surface of the mask 3 is also CCD.
The image is captured by the linear image sensor 52. Therefore, C
The CD linear image sensor 52 detects a gap window detection waveform having two peak values as shown in FIG. When the gap detector 5 moves from the position AA in the + Y direction and is located at the position AB, the gap detector 5 simply moves the gap window 5a in the + Y direction as shown in FIG. The gap window detection waveform shown in FIG. 3B is not detected from the image sensor 52. When the gap detector 5 moves from the position AB in the + X direction and exists at the position AC, the gap detector 5 simply moves the gap window 5a in the + X direction as shown in FIG. The linear image sensor 52 detects a gap window detection waveform as shown in FIG. Similarly, when the gap detector 5 moves only one position in the −Y direction from the position AC and is located at the position AD, the CCD linear image sensor 52 similarly detects a gap window detection waveform as shown in FIG. . Gap detector 5 is in position A
In the case where the gap detector 5 is further moved by one in the −Y direction from D and is located at the position AE, as shown in FIG.
Has just moved the gap window 5a in the −Y direction.
A gap window detection waveform as shown in (B) is detected. When the gap detector 5 moves in the -X direction from the position AE and is located at the position AG via the position AF, the gap detector 5 moves the gap window 5a in the -X direction as shown in FIG. Only one movement has been made, and the gap window detection waveform as shown in FIG. 4B is still detected from the CCD linear image sensor 52. Gap detector 5 is in position A
When moving from G in the + Y direction and present at the positions AH and AI, the CCD linear image sensor 52 detects a gap window detection waveform as shown in FIG.
Then, when the gap detector 5 is further moved in the + Y direction from the position AI and is located at the position AJ, FIG.
As described above, the emitted light from the LED 51 cannot pass through the gap window of the mask 3 and is reflected by the low reflection chrome pattern on the lower surface of the mask 3 and is taken into the CCD linear image sensor 52. Therefore, CC
A gap window undetected waveform as shown in FIG. 3A is detected from the D linear image sensor 52. Gap detector 5
Is moved from the position AJ in the + X direction and exists at the position AK, the light emitted from the LED 51 cannot pass through the gap window of the mask 3 as shown in FIG. The light is reflected by the low-reflection chrome pattern on the lower surface and is captured by the CCD linear image sensor 52. Therefore, from the CCD linear image sensor 52, FIG.
A gap window undetected waveform as shown in (B) is detected. This state is the same for the position AL and the position AM. Next, when the gap detector 5 moves from the position AM in the −Y direction and is at the position AO, as shown in FIG.
The light emitted from the ED 51 can pass through the gap window of the mask 3, but the light reflected on the surface of the glass substrate 1 is reflected by the low-reflection chrome pattern of the mask 3, and the CCD linear image sensor 52 No longer captured. This state is the same for the position AN and the position AP. Hereinafter, when the gap detector 5 sequentially moves in the −X direction from the position AQ to the position AV,
From the D linear image sensor 52, only the gap window undetected waveform of FIG. 3B is detected. When the gap detector 5 exists from the position AW to the position AY, FIG.
As described above, the light emitted from the LED 51 cannot pass through the gap window of the mask 3, is reflected by the low reflection chrome pattern on the lower surface of the mask 3, and is taken into the CCD linear image sensor 52. Therefore, CC
A gap window undetected waveform as shown in FIG. 3B is detected from the D linear image sensor 52. Therefore, the states of gap window detection and non-detection are as shown on the right side of FIG.
The portion of the mark corresponds to the range of the gap window, and the position AA corresponding to the center of the range is used as the gap window detection position.

The above description is based on the assumption that the gap detector 5
Is located at the position AA just in the middle of the gap window 5a. Next, a case where the gap detector 5 exists at a position AA apart from the gap window 5a will be described as an example. In this case, similarly, from position AA to position AZ, from position BA to position BZ, from position CA to position CL.
The gap detector 5 is spirally changed in order as described above, and the CC of the gap detector 5 is changed at each of these positions.
The approximate range of the gap window 5a is detected in accordance with whether the waveform detected by the D linear image sensor 52 is a gap window undetected waveform or a gap window detected waveform, and the gap detector 5 is set to the center of the gap window 5a based on the detected range. It operates to position to. The waveform detected by the gap detector 5 at each of the positions AA to CL is as shown in FIG. As is clear from this, when the gap detector 5 is located at the position AA away from the gap window 5a, the positions at which the gap window detection waveform is obtained are positions AC to AE, A
N-AP and BG-BI are nine places, and the center position is the position AO. Therefore, the gap detector 5 is moved to the position AO.
It is only necessary to position at 4 to 6, the positions shown in parentheses correspond to those in FIG. In the case shown in FIG. 1, the gap detectors 5 are sequentially positioned on the spiral, and if it is determined whether the waveform detected by the CCD linear image sensor 52 is a gap window detection waveform or an undetected waveform, the position is determined. AG-AJ, AT-B
As for E, BK to CF, and CL, useless detection is performed. Therefore, as shown in FIG. 8, for each of these positions, the grasp of the detected waveform may be omitted by skip processing. Good. That is, after the position AF, the position AK
, Skipping to the position BF following the position AS,
After the position BJ, the process skips to the position CG. By doing so, the time until the gap window position is detected can be significantly reduced. In the above-described embodiment, a case has been described where the gap detector 5 is moved by a predetermined amount when the gap detector 5 is spirally changed. May be changed to a small movement amount at the time when is detected. Further, the moving amount may be different between the X direction and the Y direction.

[0007]

According to the gap window position detecting device of the present invention, the position between the gap window provided on the mask and the gap detector can be automatically and quickly performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operation concept of a gap window position detecting method according to the present invention.

FIG. 2 is a diagram showing a schematic configuration of a proximity exposure apparatus relating to a gap window position detecting method according to the present invention.

FIG. 3 is a diagram showing an example of a waveform detected by the gap detector of FIG.

FIG. 4 is a diagram illustrating a first example of a state of a relative positional relationship between a gap detector and a gap window.

FIG. 5 is a diagram illustrating a second example of the state of the relative positional relationship between the gap detector and the gap window.

FIG. 6 is a diagram illustrating a third example of a state of a relative positional relationship between a gap detector and a gap window.

FIG. 7 is a view showing another operation concept of the gap window position detecting method according to the present invention.

FIG. 8 is a diagram showing still another operation concept of the gap window position detecting method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Exposure chuck, 3 ... Mask, 4 ...
Mask holder, 5 to 8: gap detector, 5a to 8a ...
Gap window, 9R: rear side detection optical system, 9F: front side detection optical system, 10: light emitter, 11, 14: half mirror, 12: objective lens, 13: collimator lens, 1
5, 16 ... cylindrical lens, 17, 18, 52,
62: CCD linear image sensor, 51, 61: LE
D

Claims (4)

[Claims] 1. A gap window position detecting method for automatically detecting the position of a gap window provided in a mask for exposure by using a gap detector, wherein a gap window is detected on an XY plane between the mask and the gap detector. Wherein a plurality of relative positioning positions are designated, and a range of the gap window is detected based on a type of each waveform at the positioning position detected by the gap detector. . 2. A plurality of relative positions between the mask and the gap detector on the XY plane are specified by moving at least one of the mask and the gap detector by a predetermined distance. The gap window position detecting method according to claim 1, wherein the positioning is performed by performing positioning. 3. A gap window position detecting method for automatically detecting the position of a gap window provided in an exposure mask using a gap detector, wherein a position is firstly determined between the mask and the gap detector. On the basis of the determined position, a plurality of relative positioning positions on the XY plane between the mask and the gap detector are moved by at least one of the mask and the gap detector by a predetermined distance. A method for detecting a gap window position, comprising: performing positioning by spiral positioning; and detecting a range of the gap window based on a type of each waveform at the positioning position detected by the gap detector. 4. The apparatus according to claim 1, wherein when the type of the waveform detected by said gap detector is a gap window detection waveform, a corresponding positioning position is included in the range of said gap window. Or the gap window position detection method according to 3.