JPH10335256A - Laser annealing apparatus of liquid crystal substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a liquid crystal substate placed in a vacuum chamber to be selectively irradiated with a laser beam from different directions without making the liquid crystal substrate pivot, by a method wherein a beam sectional direction change optical system which changes the sectional direction of a laser beam incident on a homogenizer interlocking with the pivoting homogenizer is provided. SOLUTION: When a liquid crystal substrate 16 is irradiated with an long beam 14 in the longitudinal direction of the liquid crystal substrate 16, mirrors 72 and 78 are moved back by air cylinders 84 and 88, and a mirror 80 is moved forth by an air cylinder 92. As a result, a laser beam 10 is reflected from the mirrors 76 and 80 and incident on a homogenizer 12 making its sectional form conform to the direction of the homogenizer 12 or the longitudinal direction of the long beam 14. Therefore, the pivoting angle of the homogenize 12 and the sectional form of the laser beam 10 incident on the homogenizer 12 can be regulated conforming to a change in the direction of irradiation of the liquid crystal substrate 16 which is placed in a vacuum chamber and hard to pivot.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser annealing apparatus for a liquid crystal substrate, and more particularly to a laser annealing method for irradiating a liquid crystal substrate made of amorphous silicon with a laser beam to reform the liquid crystal substrate into polysilicon. It is possible to selectively irradiate the laser beam to the parts that need reforming,
The present invention relates to a laser annealing device for a liquid crystal substrate.

[0002]

2. Description of the Related Art A liquid crystal substrate made of amorphous silicon is irradiated with a laser beam to anneal the liquid crystal substrate so that the substrate is modified into polysilicon. Conventionally, at the time of this laser beam irradiation, for example, as shown in FIG. 12, an excimer laser beam 10 having a cross-sectional shape of 35 mm long × 25 mm wide is passed through a total reflection mirror 11 and a homogenizer 12 having directivity, for example, with a width of 1 mm × length. 200mm long beam 1
4 and irradiate the liquid crystal substrate 16 with this to anneal it. Specifically, as shown in FIG. 13, the liquid crystal substrate 16 is set to, for example, 0.1 m so that the long beams 14 overlap by 90% in the width direction.
The laser beam was applied to the entire surface of the liquid crystal substrate 16 while being fed in the direction of arrow A by m.

However, in this full-surface irradiation, traces of the overlap line 18 remain as stripes, for example, in increments of 0.1 mm, which appear on the final display screen as a rain-like pattern. Many were out.

Therefore, as shown in FIG. 14, for example, in a six-panel liquid crystal substrate 16 that takes six displays,
There is no problem if the display display unit 20 is amorphous silicon, and the peripheral drive circuit unit 2 for switching is used.
Focusing on the fact that only the polysilicon 2 needs to be made into polysilicon, only the peripheral drive circuit section 22 is selectively irradiated with a laser beam, thereby eliminating unnecessary irradiation, improving efficiency, and reducing the generation of the overlap line 18. It is possible to prevent it.

On the other hand, when such selective irradiation is performed, the direction of the peripheral drive circuit section 22 is different by 90 ° between the upper and lower sides and the left and right sides of the display section 20.
It is necessary to change the irradiation direction by 90 ° in accordance with this.

[0006]

However, if the optical system including the homogenizer 12 is fixed and the liquid crystal substrate 16 is moved (rotated by 90 °) as in the conventional full-surface irradiation, It is necessary to provide a rotation mechanism in the vacuum chamber in which the liquid crystal substrate 16 is stored, and the vacuum chamber may be contaminated by contamination. Also, the rotating mechanism including the stepping motor and the encoder has a high temperature (the temperature in the vacuum chamber is about 400 ° C.)
It is susceptible to problems such as weakness, early deterioration, and accuracy deterioration.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to enable selective irradiation in different directions without rotating a liquid crystal substrate placed in a vacuum chamber. I do.

[0008]

SUMMARY OF THE INVENTION The present invention provides a laser annealing apparatus for irradiating a liquid crystal substrate with a laser beam having an anisotropic cross-sectional shape through a directional homogenizer to anneal the liquid crystal substrate. A homogenizer rotation mechanism for rotating the homogenizer in accordance with the direction of laser beam irradiation to the laser beam, and a beam cross-sectional direction changing optical element for changing the cross-sectional direction of the laser beam incident on the homogenizer in accordance with the rotation of the homogenizer The above-mentioned problem has been solved by providing a system.

Further, the beam cross-section direction changing optical system is
It is configured by using a total reflection mirror that can enter and exit the optical path of the laser beam, and the beam cross-sectional direction can be changed by 90 °.

Further, the reflection surface of the total reflection mirror can be finely adjusted in accordance with the deviation of the liquid crystal substrate fixing direction from the reference direction.

Further, means for detecting a deviation of the liquid crystal substrate fixing direction from the reference direction is provided so as to rotate together with the homogenizer.

[0012]

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

FIG. 1 (a cross-sectional view as viewed from the front), FIG. 2 (a cross-sectional view as viewed from the side), FIG. 3 (a cross-sectional view at the center viewed from the upper surface), and FIG. (Enlarged view from above).

The liquid crystal substrate 16 to be annealed
Is disposed on a heater 32 disposed on a carrier 30 movable in the X-axis direction (longitudinal direction of the liquid crystal substrate 16, A direction in FIG. 13) by a ball screw 28, for example.
The liquid crystal substrate 16, the heater 32, and the carrier 30 are all housed in a vacuum chamber. The vacuum chamber 34 is mounted on a gantry 36, and a window 38 for passing a long beam is provided at a position on the upper surface facing the homogenizer 12.

At a position facing the liquid crystal substrate 16 above the vacuum chamber 34, a homogenizer 12 similar to the conventional one is provided. As shown in FIG. 2, the homogenizer 12 is fixed to an inner cylinder 46 rotatably supported in an outer cylinder 40 by an upper cross roller bearing 42 and a lower ball bearing 44, and is rotatable. . The inner cylinder 46
Is a large pulley 48 attached to the upper end thereof, a small pulley 52 rotated by a servomotor 50 attached to the side surface of the outer cylinder 40, and a steel bridged between the large pulley 48 and the small pulley 52. The belt 54 is configured to rotate without backlash according to the rotation of the servomotor 50.

The side surface of the outer cylinder 40 is, as shown in FIG.
A ball screw 6 attached to a moving base 58 and rotated by a servomotor 64 (see FIG. 2) fixed to an end of a Y-axis base 62 fixed to a Y-axis frame 60.
8 allows movement in the Y-axis direction. Therefore, by rotating the servomotor 64, the irradiation position of the long beam on the liquid crystal substrate 16 in the Y-axis direction can be changed.

An optical system base 70 is provided on the upper surface of the outer cylinder 40.
4 is provided on the optical system base 70 for changing the sectional direction of the laser beam incident on the homogenizer in accordance with the rotation of the homogenizer 12 as shown in FIG.
Two total reflection mirrors (hereinafter simply referred to as mirrors) 72,
A beam cross section changing optical system 71 including 74, 76, 78, and 80 is provided.

Of the mirrors, mirrors 72, 74, 7
The mirror 6 reflects the laser beam 10 incident in the horizontal direction in the 90 ° direction in the same horizontal plane.
The laser beam 80 reflects the laser beam traveling in the horizontal plane downward toward the homogenizer 12.

As shown in detail in FIG. 5, the mirror 72 is guided by a pair of guide rods 83, and is movable on a rectilinear stage 82 which can be moved back and forth (in the direction of arrow B in FIG. 4) by a central elongated air cylinder 84. It is placed on. The angle of the reflection surface of the mirror 72 can be finely adjusted by a micrometer head 73.

The mirrors 74 and 76 are mirrors 7 in FIG.
4, the micrometer head 75 (77)
In addition, the tilt angle of the reflection surface can be finely adjusted by the motor with encoder 94 (98), and the encoder is mounted on the stage 104 (106) whose front and rear position can be adjusted by the motor with encoder 100 (102). I have.

The mirrors 78 and 80 are shown in FIG.
As illustrated in FIG. 8, the guide rod 87 (91) is guided by a pair of guide rods 87 (91), and is moved back and forth by a central elongated air cylinder 88 (92) (the mirror 78 is in the direction of arrow C in FIG. The movable stage 86 (90) is fixed at a downward angle of 45 ° on the movable stage 86 (90). The angles of the reflecting surfaces of the mirrors 86 and 90 can be finely adjusted by a micrometer head 79 (81).

When the direction of the homogenizer 12 is 0 °, for example, as shown in FIG.
The laser beam 10 is inserted into the optical path of the laser beam 10 by the air cylinders 84 and 88, and reflects the laser beam 10 in the direction of the mirror 74 and the homogenizer 12, respectively. On the other hand, when the direction of the homogenizer 12 is 90 °, the laser beam 10 The optical path is retracted from ten optical paths.

The mirror 80 is, for example, a homogenizer 1
When the direction 2 is 90 °, as shown in FIG. 9, the laser light inserted into the optical path of the laser light and reflected by the mirror 76 is reflected toward the lower homogenizer 12. . On the other hand, when the direction of the homogenizer 12 is 0 °, the homogenizer 12 is retracted from the optical path of the laser light 10.

In the vicinity of the end of the homogenizer 12 of the inner tube 46, as shown in FIG.
A pair of CCTV lens barrels 108 and 110 for detecting the alignment mark 24 as shown in FIG.

The operation of the embodiment will be described below.

As shown in FIG. 8, when irradiating the long beam 14 long in the width direction of the liquid crystal substrate 16, that is, when the direction of the homogenizer 12 is 0 °, as shown in FIG. 92, the mirror 80 is retracted, while the air cylinders 84, 88 cause the mirrors 72, 78 to retract.
Is advanced and inserted into the optical path of the laser beam 10. Then, as shown in FIG.
The light is reflected at 74 and 78 and enters the homogenizer 12 in a state where the cross-sectional shape matches the direction of the homogenizer 12, that is, the longitudinal direction of the long beam 14 to be formed.

On the other hand, when it is desired to irradiate the long beam 14 long in the longitudinal direction of the liquid crystal substrate 16, the air cylinder 84,
While the mirrors 72 and 78 are retracted by 88, the mirror 80 is advanced by the air cylinder 92. Then, as shown in FIG. 9, the laser beam 10 is reflected by the mirrors 76 and 80, and is directed in the direction of the homogenizer 12, that is, the long beam 14
When the cross-sectional shape matches the longitudinal direction of the
2 is incident.

Therefore, the rotation angle of the homogenizer 12 and the rotation angle of the homogenizer 12 are adjusted according to the change of the irradiation direction on the liquid crystal substrate 16 without rotating the liquid crystal substrate 16 which is in the vacuum chamber 34 and is difficult to rotate. , The laser light 10 incident thereon
Can be adjusted in cross section.

In actual laser irradiation, FIG.
0, the liquid crystal substrate 16 may be arranged on the carrier 30 so as to be shifted from the reference direction (X). In this case, the inner cylinder 46, that is, the homogenizer 12 is rotated by an angle θ in accordance with the position of the alignment mark 24 detected via the CCTV lens barrels 108 and 110, and a long image formed by the homogenizer 12 is formed. Although the irradiation direction of the beam 14 can be matched with the irradiation position of the liquid crystal substrate 16, the incident angle of the laser beam 10 formed by the optical system 71 with respect to the homogenizer 12 is slightly shifted. Therefore,
As shown in FIG. 11, first, motors with encoders 94 and 98 are provided.
Mirror 74 (in the case of direction 0 °) or mirror 7
6 (in the case of a direction of 90 °), the position shifted by the tilt adjustment is adjusted by adjusting the front and rear positions of the mirrors 74 and 76 by the motors 100 and 102 with encoders. In accordance with the minute rotation of 12, the cross-sectional shape of the laser beam incident thereon can be finely adjusted.

In this embodiment, five mirrors 7
Homogenizer 1 using 2, 74, 76, 78, 80
Since the optical path length of the laser light does not change when the direction of 2 is 0 ° or 90 °, high-precision irradiation can be performed even when the cross-sectional size of the laser light changes according to the optical path length. .

In this embodiment, a beam sectional direction changing optical system for changing the sectional direction of the laser beam incident on the homogenizer in accordance with the rotation of the homogenizer is constituted by using five mirrors. Therefore, the configuration is simple. The configuration of the beam cross-section direction changing optical system is not limited to this, and the number of mirrors can be changed or a prism can be used.

[0032]

According to the present invention, selective irradiation in different directions can be performed without rotating the liquid crystal substrate. Therefore,
There is no need to provide a mechanism for rotating the liquid crystal substrate in the vacuum chamber, so that contamination in the vacuum chamber can be prevented. In addition, it is possible to prevent the life of the rotating mechanism from being shortened and the accuracy from being lowered when the rotating mechanism is provided in a high-temperature vacuum chamber.

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view showing the overall configuration of an embodiment of a liquid crystal substrate laser annealing apparatus according to the present invention.

FIG. 2 is a sectional view of the same side view.

FIG. 3 is a cross-sectional view of a central portion also seen from the top.

FIG. 4 is an enlarged top view showing the configuration of an optical system for changing the beam cross-sectional direction in the same manner.

FIG. 5 is a perspective view showing an attached state of some mirrors of the optical system.

FIG. 6 is a perspective view showing a mounting state of another mirror.

FIG. 7 is a perspective view showing a mounting state of still another mirror.

FIG. 8 is an essential part perspective view showing a laser beam irradiation state when the direction of the homogenizer is 0 °.

FIG. 9 is a main part perspective view showing a laser light irradiation state when the direction of the homogenizer is 90 °.

FIG. 10 is a plan view for explaining the alignment adjusting method of the embodiment.

FIG. 11 is a diagram illustrating a method of finely adjusting the laser cross-sectional shape in accordance with the alignment adjustment.

FIG. 12 is a perspective view showing an example of a relationship between a homogenizer and a liquid crystal substrate.

FIG. 13 is a plan view for explaining a conventional whole-surface irradiation method.

FIG. 14 is a plan view showing an example of a display unit and a peripheral drive circuit unit on a liquid crystal substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Laser beam 12 ... Homogenizer 14 ... Long beam 16 ... Liquid crystal substrate 20 ... Display display part 22 ... Peripheral drive circuit part 24 ... Alignment mark 30 ... Carrier 32 ... Heater 34 ... Vacuum chamber 36 ... Stand 40 ... Outer cylinder 46 ... Inner cylinder 48, 52 Pulley 50, 64 Servo motor 54 Steel belt 56 Linear guide 58 Moving base 60 Y-axis frame 62 Y-axis base 70 Optical system base 71 Optical system 72 for changing beam cross-sectional direction , 74, 76, 78, 80 ... Total reflection mirror 82, 86, 90, 104, 106 ... Stage 94, 98, 100, 102 ... Motor with encoder

Claims (4)

[Claims] 1. A laser beam having an anisotropic cross-sectional shape,
In a laser annealing apparatus for irradiating a liquid crystal substrate with a liquid crystal substrate through a directional homogenizer and performing annealing, a homogenizer rotation mechanism for rotating the homogenizer in accordance with a laser beam irradiation direction on the liquid crystal substrate, and a rotation of the homogenizer. A beam cross-sectional direction changing optical system for changing the cross-sectional direction of the laser beam incident on the homogenizer in accordance with the movement, enabling selective irradiation in different directions without rotating the liquid crystal substrate. Characteristic laser annealing equipment for liquid crystal substrates. 2. The optical system according to claim 1, wherein said beam sectional direction changing optical system is constituted by using a total reflection mirror which can enter and exit in the optical path of the laser beam, and has a beam sectional direction of 90 °.
A laser annealing apparatus for a liquid crystal substrate, wherein the apparatus can be changed. 3. A laser annealing method for a liquid crystal substrate according to claim 2, wherein the reflecting surface of said total reflection mirror can be finely adjusted in accordance with a deviation of a liquid crystal substrate fixing direction from a reference direction. apparatus. 4. A laser annealing apparatus for a liquid crystal substrate according to claim 1, wherein means for detecting a deviation of the liquid crystal substrate fixing direction from the reference direction is provided so as to rotate together with said homogenizer.