JP3140349B2 - Positioning device for rectangular substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a positioning device for a rectangular substrate, and more particularly to a positioning device capable of positioning a large liquid crystal panel in a non-contact state.

[0002]

2. Description of the Related Art With the advance of technology, large liquid crystal panels have been developed and widely used in various fields. A liquid crystal panel (hereinafter simply referred to as an LCD panel) is a device in which minute pixels are formed in a matrix on the surface. A pattern such as a thin film transistor, a resistor, a capacitor, and a pixel electrode is formed on a glass substrate by an exposure apparatus. At the stage when the pattern is formed, inspection is performed by the inspection device. An exposure apparatus and an inspection apparatus are provided with a chuck table on which an LCD panel and a glass substrate are placed.
The panel 1 is sucked and held. An X, Y, and Z moving mechanism is provided below the chuck table. An exposure optical system is provided in the exposure apparatus above the chuck table, and an inspection optical system is provided in the inspection apparatus. The LCD panel is positioned such that the center of the LCD panel 1 matches the center position of these optical systems. In addition to these, there is a control system for controlling the movement of the chuck table as a control system.

A large LCD panel has a vertical and horizontal dimension of, for example, 300 mm or 400 mm, and a thickness d of about 1 mm. The LCD panel is basically based on a glass substrate. In the case of a TFT LCD panel, a pattern including the above-described thin film transistor, a resistor, a capacitor, a pixel electrode, and the like is formed on the surface of the panel by a photolithographic method. Here, for convenience of explanation, including the glass substrate before pattern formation, an LCD panel will be described as a representative.

FIG. 5 is a plan view centering on a chuck table of a conventional exposure stage or inspection stage. An LCD panel 1 is mounted on a chuck table 2.
A positioning mechanism 5 for the LCD panel 1 is provided around the periphery. The two long sides of the LCD panel 1 are 1A, 1B, 2
Suppose that the short side is 1C and 1D, the long side is placed in the X direction, and the short side is placed in the Y direction. To the long side 1A, positioning air cylinder 5a, each having a stopper St _a, the St _b,
5b is a pressing air cylinder 5c against the long side 1B.
, 5d are provided respectively. Air cylinder 5a, 5c
, And 5b and 5d respectively have an action line C _{1 in the} Y direction.
, Is on C _2, the point of application of the LCD panel 1 against these pressing force or reaction force, p _a, p _c, and p _b,
p _d . On the other hand, the short side 1C, relative to 1D, a positioning air cylinder 5e and pressing air cylinder 5f having a stopper St _e are each disposed on a line of action C ₃ in the X direction, the point of application of force p _e, it is a p _f.

In positioning the LCD panel, first, the air cylinders 5a to 5f are operated in opposite directions to retract the pressing rods (positioning pins) 51, and then the LCD panel 1 is transported by a handling mechanism (not shown). Then, it is mounted on the mounting table 2 at an approximate position. here,
Each positioning air cylinder 5a, when operated 5b and 5e moves the positioning pins 51, each of the tip stopper St _a, St _b, stopped by St _e in a fixed position for positioning. Then, each pressing air cylinder 5c, 5d and 5
By the operation of f, each positioning pin 51 is moved to the long side 1
The point p _c of B and short 1D, p _d, a p _f pressed, LC
The D panel 1 moves and is positioned in the state shown in the figure. In particular, the positioning of the center of the LCD panel with respect to the center of the optical system at the time of exposure is called pre-alignment, and more accurate positioning is performed by aligning the alignment mark formed on the LCD panel 1 after the center positioning is completed. Done with reference.

[0006]

The surface of the chuck table 2 is extremely flat and smooth because it is necessary for focusing on the optical system 4 for inspection or exposure. On the other hand, since the large LCD panel 1 has a small thickness d in spite of its large area as described above, the large LCD panel 1 comes into close contact with the chuck table 2 when it is placed on the chuck table 2, and a considerably large frictional resistance is generated between the two. . Now, the LCD panel 1 is X
Assuming that the LCD panel 1 is placed with an angle shift with respect to the Y direction, the LCD panel 1 does not move due to the frictional resistance, and thus the angle shift is not corrected. This will be described with reference to FIG.
In FIG. 6, it is assumed that the LCD panel 1 is mounted to be inclined rightward. First, each positioning air cylinder 5a, 5b
, 5e, the tip of each positioning pin 51 stops at the positioning position. Then the pressing air cylinder 5c, 5d, the operation of 5f, LCD panel 1 is the point p _c, p _d, p _f is moved by being pressed, the point p
_a, p _e is stopped in contact with the positioning pin 51. However, LCD panel 1 because the frictional resistance is large is not rotated, thus the state shown in which the point p _b is separated. That is, the angle deviation δθ is not corrected. The above is the case where the LCD panel 1 is tilted to the right. However, when the LCD panel 1 is tilted to the left, the angle shift is not corrected in the same manner as described above.

Further, the resist near the edge is peeled off, or chipping occurs at the end due to the contact of the positioning pin 51 with the end face of the LCD panel 1. Peeling of the resist causes dusting, and chipping causes failure. SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art, and to provide a positioning apparatus for a rectangular substrate such as an LCD panel which can position a rectangular substrate in a non-contact manner.

[0008]

The features of the rectangular substrate positioning apparatus of the present invention for achieving the above object are as follows.
The first stage, which is arranged at one of the X and Y reference positions of the XYθ stage and held by the base holding the XYθ stage when the XYθ stage is in the initial state, optically detects the edge of one side of the rectangular shape of the substrate. Edge sensor and XYθ
When the stage is in the initial state, X,
The XYθ stage is arranged at a reference position of one of the other Y and at a predetermined distance L in one direction, and is held.
Second and third edge sensors that are held by a base and optically detect the edge of the other side orthogonal to the one side of the substrate, and the substrate is moved from a predetermined initial position where the XYθ stage is set in an initial state. The respective movements until the respective edges are detected by receiving the detection signals from the first, second, and third edge sensors while relatively moving toward the first, second, and third edge sensors. And the angle of the XYθ stage with respect to the initial position, the X direction, and the Y direction.
Position correcting means for correcting the respective positions in the directions. And second and third edge sensors
At the initial position along the other of X and Y directions.
Placed at a position symmetrical to the vertical line and separated by a predetermined distance L
And the position correcting means moves the substrate relative to a predetermined reference position.
To the second and third edge sensors.
The respective movement amounts A1 and A2 are obtained, and θ = arctan {(A1−A
2) / L} to obtain the rotation angle (where L is the predetermined distance
Separation), thereby correcting the angle by −θ, and substantially
Returning to the initial position direction by the distance of (A1 + A2) / 2, the first
Move by moving the board relatively toward the sensor
The position is corrected in this direction by obtaining the amount.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rectangular substrate is an LCD panel in the embodiment, but is not limited to an LCD panel. A substrate such as a ceramic substrate or a synthetic resin substrate may be used as long as the substrate is arranged on the XYθ stage of the inspection apparatus or the exposure apparatus. In the embodiment, XY in which a Z stage is added in addition to the XYθ stage
It is a Zθ stage. The edge sensor disposed around the outside of the XYθ stage can be detected in a non-contact state as long as it is a sensor capable of optically detecting the edge of the side of the substrate. In the embodiment, the edge sensor is fixed and the XYθ stage side moves in the XY directions. However, the XYθ stage side is fixed and the edge sensors in the X direction and the Y direction move in the respective directions. A configuration such as moving may be adopted. In the present invention, as described above, the optical edge sensor is disposed at the reference position where this side corresponding to one side of the substrate is to be positioned, and the two edge sensors are disposed at the reference position corresponding to the other side of the substrate. Since the other side is arranged at the reference position to be positioned, XYθ
By the relative movement of the substrate via the stage, it is possible to obtain the amount of movement of three points to each reference position of each edge sensor, thereby obtaining the rotation angle and the amount of correction in the X and Y directions. In particular, the second and third edge sensors are X,
At a position that is symmetric to a line along one of the other Y directions
It is arranged at a predetermined distance L, and the position correcting means
Second and third edge sensors relatively from a predetermined reference position
To obtain the respective movement amounts A1 and A2
Then, the rotation angle is obtained by θ = arctan {(A1−A2) / L}, and
As a result, the angle is corrected by -θ, and substantially (A1 +
A2) Returning to the initial position direction by a distance of / 2, the first sensor
Relative movement of the substrate in the direction of
By performing position correction in the lever direction, the center position of the substrate
The setting is θ correction, return correction to the initial position (origin), and
3 minutes, that is, correction of origin shift in one of X and Y directions
Since the correction is divided, simple correction calculation
And high accuracy center positioning
You. This makes it possible to supplement X, Y, and θ for center positioning.
There is no need for cumbersome calculation processing to calculate the positive amount at the same time.
You. Further, since this correction amount is obtained in a non-contact manner, the resist near the edge is hardly peeled off, and dust is hardly generated. Furthermore, there is almost no occurrence of chipping failure due to positioning.

[0010]

FIG. 1 is a plan view mainly showing a chuck table of an exposure stage of a large LCD panel to which a substrate positioning apparatus according to the present invention is applied, FIG. 2 is a side view thereof, and FIG. Is a flowchart of a positioning process for an LCD panel, and FIG. 4 is a plan view of a chuck table for positioning a small LCD panel. In FIG. 1, 1
Reference numeral 0 denotes an exposure stage, and the LCD panel 1 is mounted on the chuck table 20. The conventional chuck table 2 of FIG. 5 is a slightly larger chuck table such that an edge is arranged outside the edge of the LCD panel 1, whereas the chuck table 20 of FIG.
Is slightly smaller than the LCD panel 1,
Is different from the chuck table 2 in that the edge protrudes outward. Further, the chuck table 20 is provided with a suction hole 21 at a center portion for sucking the LCD panel 1 and suction holes 21a, 21b, 21c, 21d at a center position of each area divided into two vertically and horizontally. On the lower side of the back surface of the chuck table 20,
As shown in FIG. 2, an XYZθ moving stage 3 in which a θZ rotation moving mechanism 3b is stacked on an XY moving mechanism 3a is provided. The XYZθ moving stage 3 is disclosed in Japanese Patent Application Laid-Open No. 7-83 filed by the present applicant.
No. 793 (Japanese Patent Application No. 5-252318), which is already publicly known, the details thereof are omitted.

[0011] suction holes 21, as shown in Figure 1, are located in the center of the chuck table 20, when an XYZ direction as shown, the center line Yo in the Y direction through the suction hole 21 The Y-direction edge detection optical sensor (hereinafter, edge sensor) 6 is located at a position slightly away from the edge of the LCD panel 1 so that the centers coincide with each other, and the detection position is the reference position in the Y direction (Y direction of the LCD panel 1 in the Y direction). (The position of the edge in the direction is to be originally positioned). Further, the edge sensors 7 and 8 in the X direction are symmetrical with respect to the center line Xo in the X direction passing through the suction hole 21 and the reference position in the X direction at a position slightly away from the edge of the LCD panel 1 (LC in the X direction).
It is provided so that the edge of the D panel 1 in the X direction coincides with the position at which the D panel 1 should be positioned. Here, the distance between the detection positions of the edge sensors 7 and 8 is L. The edge sensors 6, 7, 8 are attached to the base 9 to which the chuck table 20 is fixed. And
When one side in the X direction and one side in the Y direction of the LCD panel 1 coincides with the detection position of the edge sensor, the center of the LCD panel 1 is moved to the center of the exposure optical system 4 (see FIG. 2) disposed above the LCD panel 1. Match, which results in LC
The positioning of the D panel 1 is completed. In particular, in the exposure apparatus, the pre-alignment of the LCD panel 1 is thereby completed.

The configuration of the edge sensors 6, 7, 8 is based on an LCD.
The position of the panel 1 is detected by vertically irradiating the surface of the panel 1 with laser light and blocking the irradiated light. As shown in FIG.
These edge sensors are arranged at a position higher than the surface of the chuck table 20 and emit a laser beam in the horizontal direction. The laser light source 11 receives a beam from the laser light source 11 in the horizontal direction and reflects the beam in the vertical direction. An upper mirror 12, a lower mirror 13 arranged at a position lower than the back surface of the chuck table 20, receiving the beam from the upper mirror 12, and reflecting the beam in the horizontal direction, and a light receiving element 14 for receiving the beam from the lower mirror 13 And a U-shaped frame 15 for supporting them.

The detection signal of the light receiving element 14 is sent to a data processing / control circuit 17 via detection circuits 16, 16, 16 provided corresponding to the respective sensors. As shown in FIG. 2, the detection circuit 16 includes an amplifier (AMP) 16a for amplifying a detection signal of the light receiving element 14 and a comparator (C).
OM) 16b, and the comparator 16b generates an edge detection signal when the output of the amplifier 16a falls below the reference value. The data processing / control circuit 17 includes an MPU
17a, a memory 17b, etc.
Receive the edge detection signal from
It receives a signal from a CCD sensor or the like (not shown) of the detection exposure optical system 4 disposed above the chuck table 20. In addition, a control signal for moving the XYZθ moving stage 3 by a predetermined amount is sent to the table drive control circuit 18. The memory 17b is provided with a movement control program 17c for controlling the XYZθ movement stage 3 and a position correction processing program 17d.

Next, the positioning process of the LCD panel 1 will be described with reference to FIG. First, the chuck table 20 is set at an initial position (origin position) (step 10).
0). Next, the LCD panel 1 is placed on the chuck table 20, and is held by suction (Step 101). Then, the movement control program 17c is executed to move the chuck table 20 in the X direction toward the edge sensors 7 and 8 at a constant speed (step 102). Next, the MPU 17a of the data processing / control circuit 17
(Step 103). When an edge detection signal is obtained from one of the edge sensors 7 and 8, the amount of movement of the chuck table 20 at that time is stored in a memory location corresponding to the sensor from which the edge detection signal was obtained in the memory 17b in accordance with the edge detection signal. To memorize. For example, if an edge detection signal is obtained from the edge sensor 7, the amount of movement from the origin to the storage position FX1 of the edge sensor 7, ie, the X coordinate value from the origin, is X
1 is stored (step 104).

Next, a loop for waiting for signals from the edge sensors 7 and 8 is entered again (step 105). As described above, an edge detection signal is obtained from one of the edge sensors 7 and 8. In this example, the edge detection signal of the edge sensor 8 is obtained this time, and the movement amount of the chuck table 20 at that time is stored in the memory 17b at the storage position corresponding to the sensor from which the edge detection signal was obtained. (Step 106). At this time, since the signal is an edge detection signal from the edge sensor 8, the storage position F of the edge sensor 8 is stored.
X2 is stored in X2 as the movement amount from the origin, that is, as the X coordinate value. Then, the chuck table 20 is returned to the initial position (Step 107), and the rotation amount θ is corrected by the following equation. θ is determined by θ = arctan {(X1−X2) / L}, and the chuck table 20 is rotated by −θ (step 108). Here, L is the distance between the edge sensor 7 and the edge sensor 8. Further, X-axis correction is performed by the following equation. X = (X1 + X2) / 2 The correction amount X3 is obtained by using
It is moved by -X3 in the axial direction (step 109).

After the X-axis correction, the chuck table 20 is moved at a constant speed in the Y direction toward the edge sensor 6 at the position of the chuck table 20 (step 11).
0). The MPU 17 of the data processing / control circuit 17
a enters a signal waiting loop from the edge sensor 6 (step 111). If an edge detection signal is obtained from the edge sensor 6, the movement amount from the origin, that is, Y1 is stored in the storage position FY1 of the edge sensor 6 (step 112). Then, the chuck table 20 is moved by -Y1 in the Y-axis direction as Y-axis correction (step 113). The position obtained as described above becomes the original origin position, and the center of the LCD panel 1 coincides with the center of the exposure optical system 4, and the LCD panel 1 is positioned (pre-aligned).

FIG. 4 shows an example of a chuck table on which the LCD panel 1 smaller than the size of the chuck table 20 can be positioned.
In the figure, “a” denotes elongated holes 22a and 22b in the X direction for passing the beams of the edge sensors 6, 7, and 8 and elongated holes 22c and 22d in the Y direction in the X and Y directions, respectively, according to the size of the small LCD panel 1. X is provided along each side of
The length of the long holes 22a and 22b in the direction is twice or more the maximum value of the Y-axis correction amount in consideration of the positive and negative directions.
Similarly, the length of the long holes 22c and 22d in the Y direction is twice or more the maximum value of the X-axis correction amount. Further, as shown in FIG. 2, since the edge sensors 6, 7, and 8 have a U shape, a beam for edge detection can enter the positions of the long holes 22a to 22d. Alternatively, the length of the arm portion on the distal end side of the U-shape is increased so that the upper mirror 12 and the lower mirror 13 are supported so as to be able to do so.

As described above, in the embodiment, the edge sensors 6, 7, and 8 are fixed, but these are coupled to a moving mechanism so as to move along respective axes, and the chuck table 20a is set at the origin. The edge sensors 6, 7, 8 can be moved in a fixed state. Thus, the respective coordinate values X1, X2, Y1 may be obtained. When the sensor side is moved in this way, these values can be obtained at the same time, whereby the -θ correction, the initial position
Direction, and position correction in either direction.
By doing so, the time for the correction process is reduced. Further, the sensor here transmits the light beam and detects the edge by blocking the beam, but a sensor that detects irregularly reflected light of the edge by a reflection type optical sensor may be used. . Further, X, Y in the embodiment
Are relative, and the X direction and the Y direction may be interchanged.

[0019]

As described above, in the rectangular substrate positioning apparatus according to the present invention, the optical edge sensor is arranged at the reference position corresponding to one side of the substrate to be positioned, and the two edge positions are determined. Since the edge sensor is arranged at the reference position where the other side corresponding to the other side of the substrate is to be positioned, the relative movement of the substrate via the XYθ stage causes the reference position of each edge sensor to be determined. Up to three points can be obtained, whereby the rotation angle and the correction amounts in the X and Y directions can be obtained.
Further, since this correction amount is obtained in a non-contact manner, the resist near the edge is hardly peeled off, and dust is hardly generated. Furthermore, there is almost no occurrence of chipping failure due to positioning.

[Brief description of the drawings]

FIG. 1 is a plan view centering on a chuck table of an exposure stage of a large LCD panel according to an embodiment to which a substrate positioning apparatus of the present invention is applied.

FIG. 2 is a side view of a chuck table of the inspection stage for the large LCD panel in FIG. 1;

FIG. 3 is a flowchart of a positioning process for an LCD panel.

FIG. 4 is a plan view of a chuck table for positioning a small LCD panel.

FIG. 5 is a plan view of a conventional chuck table of an inspection stage for a large LCD panel.

FIG. 6 is an explanatory view of an angle shift of a conventional chuck table.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Large-sized LCD panel, 2,20 ... Chuck table, 3 ... XYZθ movement stage, 4 ... Optical system, 6,7,8 ... Edge sensor, 9 ... Base, 11 ... Laser light source, 12 ... Top mirror, 13 ... Lower mirror, 14: light receiving element, 16: detection circuit, 17: data processing / control circuit, 17a: MPU, 17b: memory, 17c: movement control program, 17d: position correction processing program, 18: table drive control circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-76102 (JP, A) JP-A-9-61775 (JP, A) JP-A 7-27147 (JP, U) JP-A 7-27147 22546 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/13 101

Claims (2)

(57) [Claims] 1. XYθ capable of two-dimensional movement and rotation of XY
In a rectangular substrate positioning device for positioning a rectangular substrate placed on a stage at a predetermined position with respect to an optical system provided on the stage , the XYθ stage is
Said XYθ stage X, is arranged on one of the reference position of the Y in front Symbol XYθ stage when in the initial state
First edge sensor is held by the base for detecting the edge of one side of the rectangle of the substrate optically but held, the XY
X of the XYθ stage when θ stage is in the initial state, held in the base and the other of the reference position a and the disposed a predetermined distance L in one direction before Symbol XYθ stage Y is held second, a third edge sensor, the substrate said XYθ stage for by detecting the edge of the other side orthogonal to the one side of the substrate optically is
It is relatively moved from a predetermined initial position set in an initial state toward the first, second, and third edge sensors to receive detection signals from the first, second, and third edge sensors. The position of correcting the angle of the XYθ stage with respect to the initial position and the respective positions in the X and Y directions with respect to the initial position based on the respective movement amounts until the respective edges are detected. Correction means, wherein the second and third edge sensors are located at the initial position.
Symmetrical to a line along the other of the X and Y directions
At a predetermined distance L from each other,
The position correcting means moves the substrate relative to a predetermined reference position.
To the second and third edge sensors.
The respective movement amounts A1 and A2 are obtained, and θ = arctan {(A1−
A2) / L} (where L is the predetermined value
Distance), thereby correcting the angle by −θ and substantially
Return to the initial position direction by the distance of (A1 + A2) / 2
Relative to the substrate towards the first sensor
An apparatus for positioning a rectangular substrate that moves to obtain the amount of movement and corrects the position in this direction . 2. The method according to claim 1, wherein the substrate is a liquid crystal panel or a glass substrate thereof, and the first, second, and third edge sensors generate a beam in a direction perpendicular to the surface of the substrate and block the beam. is used to detect the edges in Rukoto, first edge sensor is substantially in the initial position
Substantially along a line along one of the X and Y directions.
And the initial position is the X
The origin, which is the intersection of the XY axes of the Yθ stage, is the initial state
The positioning device for a rectangular substrate according to claim 1 , wherein the position is determined by: