JP4845280B2 - Laser annealing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser annealing apparatus for growing crystal grains by heating a semiconductor film on a substrate by laser irradiation.
[0002]
[Prior art]
As one of the applications of laser, annealing to a thin film transistor (TFT) used for a liquid crystal display (LCD) or the like is attracting attention. For example, Japanese Patent Application Laid-Open No. 4-37144 irradiates an excimer laser with characteristics. “A method for manufacturing a thin film transistor” is disclosed.
[0003]
Laser annealing is used to form a polysilicon film and activate the contact layer. The silicon film is melted and crystallized by laser irradiation to become polysilicon. A high-quality film is formed because it undergoes a melting process once. Laser energy is absorbed by the semiconductor film. If the laser is a pulse, since the pulse width is about several tens of ns, the melting time of silicon is about several hundreds of ns, and there is almost no influence on the underlying glass substrate. In addition, other low temperature forming methods such as “Infrared annealing method” disclosed in Japanese Patent Application Laid-Open No. 61-32419 require annealing for a long time at a high temperature of about 1000 to 1200 ° C. for polysilicon formation and activation, and the glass substrate is distorted. Diffusion of impurities becomes a problem, but laser annealing allows formation at a maximum temperature in the range of 400 ° C., and there is no such problem.
[0004]
The operating speed of TFT is mobility (unit: cm ² / V · s). The mobility of polysilicon TFT is 10-600cm ² / V · s. This mobility is wide because it depends on both grain size and grain boundary. In order to obtain high mobility, it is necessary to be close to a single crystal with fewer intragranular defects and to form a grain boundary with low defects. In general, the larger the particle size and the fewer the defects at the grain boundaries, the higher the mobility.
[0005]
FIG. 4 is a structural diagram of a conventional laser annealing apparatus. The laser used is, for example, XeCL, ArF, KrF, XeF excimer laser, YAG laser, or the like. The laser beam is introduced into the chamber through an optical system centered on a beam homogenizer. The inside of the chamber is controlled to a vacuum or a gas atmosphere by a pump system and a gas system. The beam is scanned by moving the stage or the optical system.
[0006]
FIG. 5 schematically shows a manufacturing process of the low-temperature polysilicon TFT. In this figure, (1) forms amorphous silicon (a-Si) on the surface of the glass substrate, (2) converts a-Si to polysilicon (poly-Si), and dry-etches (3 The surface is covered with an insulating coating (SiO 2), an electrode film is formed in (4), and doping is performed in (5).
In laser annealing, poly-Si is heated in the above (2) and (5), the crystal grain size is increased, and impurities implanted by doping are diffused to enhance the bond with silicon, and high mobility. Applied to get a degree.
[0007]
On the other hand, as disclosed in Japanese Patent Application No. 2001-021032, the inventors irradiate a thin film transistor formed on a substrate with laser light that can pass through the substrate from the substrate side to activate the polysilicon constituting the thin film transistor. Invented a new laser annealing method characterized by
According to this method, since the laser light is transmitted through the substrate, irradiation can be performed through the substrate from the substrate side, and all of the TFTs (thin film transistors) can be formed without being blocked by a gate film or the like on the surface of the substrate. Polysilicon can be annealed. Thereby, the activity of silicon after doping can be maximized, and an excellent semiconductor film having a short processing time and less risk of substrate distortion can be obtained.
[0008]
Further, as disclosed in Japanese Patent Application No. 2001-020893, the inventors have invented a new laser annealing apparatus in which the optical axis of the laser beam on the irradiation surface of the substrate and the orthogonal axis of the irradiation surface of the substrate intersect at a predetermined angle. did. If laser annealing of the substrate is performed using this device, the optical axes of the reflected light on the semiconductor film surface and the reflected light on the back surface of the semiconductor are shifted, so that mutual interference due to the path difference between the reflected light can be prevented. The intensity distribution of the reflected laser light is not uneven. Therefore, there is no unevenness in the resistivity distribution of the semiconductor on the activated substrate, the crystal grain size distribution or mobility distribution of the crystallized semiconductor, and a semiconductor with good characteristics can be obtained.
[0009]
Hereinafter, for convenience of explanation, the surface of the substrate on which the thin film transistor to be processed is formed is referred to as the front surface, and the opposite surface is referred to as the back surface. Since the thickness of the substrate is thin relative to its size, it is easy to bend when horizontal. Furthermore, in order to prevent contamination of the surface of the substrate as much as possible, avoid contact with the surface of the device. Therefore, when handling the substrate, it is common to support the back surface of the horizontal substrate with the back surface facing downward. In particular, in order to maintain the flatness of the surface of the substrate, the entire back surface is supported uniformly. For example, a plurality of pins whose upper ends are in the same plane are set up vertically to support the entire back surface uniformly.
[0010]
[Problems to be solved by the invention]
In order to anneal the substrate by the new laser annealing method invented by the inventors, laser irradiation is performed from the back side of the substrate. In a conventional laser annealing apparatus, a substrate is supported on a stage, and a laser beam is irradiated from above the substrate. If the new laser annealing method is performed with a conventional laser annealing apparatus, it is necessary to support the surface of the substrate on the stage and face the back surface of the substrate upward. Also, in the front and back processes of a laser annealing apparatus, it is usual to support the back surface from below and handle it. Therefore, auxiliary equipment that inverts the top and bottom of the substrate surface at the entrance and exit of the laser annealing apparatus and transfers it to the stage. Is newly required.
Since fine semiconductor films are densely provided on the surface of the substrate, it is practically difficult to support the surface of the substrate. It is also expected that it will be difficult to develop new auxiliary equipment.
Therefore, an excimer laser annealing apparatus having a structure suitable for the implementation of the new laser annealing method has been desired.
[0011]
The present invention has been devised in view of the above-described problems, and is suitable for the implementation of the above-described new laser annealing method in place of the conventional laser annealing apparatus, and maximizes the activity of the semiconductor film. It is intended to provide an excellent laser annealing apparatus that can perform processing, has a short processing time, and has a low risk of substrate distortion.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a laser annealing apparatus for irradiating a substrate with a laser while horizontally transporting the substrate according to the present invention includes a front gas levitation stage and a rear gas levitation stage arranged in the transport direction with a predetermined gap therebetween. A gas levitation device capable of blowing gas from the upper surface and allowing the substrate to gas levitate, a horizontal feed device for horizontally sending the gas levitation substrate across the gap, and irradiating the laser beam upward from the gap And a laser optical system.
[0013]
With the above-described configuration of the present invention, the gas levitation apparatus has a front gas levitation stage and a rear gas levitation stage, and the front gas levitation stage and the rear gas levitation stage are arranged in the transport direction with a predetermined gap therebetween, Gas can be blown out from the upper surface to float the substrate. The horizontal feeding device can feed the gas floating substrate in the horizontal direction across the gap. The laser optical system irradiates the laser beam upward from the gap.
If the substrate having the semiconductor film is placed on the gas levitation stage with the surface facing upward, the substrate floats on the front gas levitation stage and the rear gas levitation stage, and is sent horizontally across the gap, from the gap. Since the lower surface is irradiated with the laser beam and the laser light is transmitted through the substrate, the surface can be irradiated through the substrate from the rear surface.
Thereby, the activity of the semiconductor film can be maximized, the processing time is short, and an excellent semiconductor film having a low risk of substrate distortion can be obtained.
[0014]
Furthermore, the laser annealing apparatus according to the present invention is provided with a reflecting plate that is provided above the gap and that can reflect the laser beam irradiated from below to below.
According to the configuration of the present invention, the reflector is provided above the gap, reflects the laser beam emitted from below, reflects the laser beam emitted upward from the gap, and further reflects the semiconductor film. Can be heated.
[0015]
Furthermore, in the laser annealing apparatus according to the present invention, the laser beam is a linear beam that intersects the substrate orthogonal axis at a predetermined angle.
With the configuration of the present invention, the laser beam is a linear beam that intersects the substrate orthogonal axis at a predetermined angle, and the linear beam irradiates the substrate intersecting the substrate orthogonal axis at a predetermined angle. Is done.
If the substrate having the semiconductor film is placed on the gas levitation stage with the surface facing upward, the optical axes of the reflected light on the semiconductor film surface and the reflected light on the back surface of the semiconductor are shifted. Interference can be prevented and the intensity distribution of the reflected laser light is not uneven. Therefore, there is no unevenness in the resistivity distribution of the semiconductor on the activated substrate, the crystal grain size distribution or mobility distribution of the crystallized semiconductor, and a semiconductor with good characteristics can be obtained.
[0016]
Further, the laser annealing apparatus according to the present invention includes a substrate support device having a plurality of pins that can horizontally support the lower surface of the substrate and a pin lifting mechanism that can move the pins up and down through the gas levitation stage. It was supposed to be.
With the configuration of the present invention, the plurality of pins of the substrate support apparatus can horizontally support the lower surface of the substrate, and the pin lifting mechanism of the substrate support apparatus can move the plurality of pins up and down through the gas levitation stage. The support device can horizontally support the lower surface of the substrate, move the substrate up and down above the gas levitation stage, and can exchange the substrate with the gas levitation stage.
[0017]
Furthermore, the laser annealing apparatus according to the present invention adjusts the height of the lower surface of the substrate by adjusting the gas bearing disposed in the gap and blowing the gas from the upper surface to float the lower surface of the substrate and supporting the substrate, and the amount of the gas blown out. A substrate height adjusting device having a control device was provided.
According to the configuration of the present invention, the gas bearing of the substrate height adjusting device is arranged in the gap and blows out gas from the upper surface to float the lower surface of the substrate to support the substrate. The height of the lower surface of the substrate is adjusted by adjusting the amount of blowout, and the substrate height adjustment device can adjust the height of the lower surface of the substrate near the gap, and the laser beam irradiated upward from the gap The beam shape is stable.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
[0019]
A structure of a laser annealing apparatus according to an embodiment of the present invention will be described. FIG. 1 is a plan view of an embodiment of the present invention. FIG. 2 is a side sectional view of an embodiment of the present invention. FIG. 3 is a partial detail view of FIG.
[0020]
The laser annealing apparatus 1 includes a substrate gas floating device 10, a substrate horizontal feeding device 20, a laser optical system 30, a substrate height adjusting device 40, a substrate lifting device 50, a substrate loader 60, a cassette station 70, an operation panel 80, and a surface plate 90. It consists of. For convenience of explanation, when the substrate is laser-annealed, the direction in which the substrate moves is referred to as the front-rear direction, with the destination being the front, and both sides are referred to as the left-right direction.
[0021]
The substrate gas levitation apparatus 10 is an apparatus that supports the substrate in a non-contact manner when the substrate is irradiated with a laser, and includes a rear gas levitation stage 11 and a front gas levitation stage 12. Each gas levitation stage 11, 12 is disposed on the surface plate 90 so that each gas levitation stage 11, 12 includes an upper surface on the same plane and is horizontal with a predetermined gap therebetween. The upper surfaces of the gas levitation stages 11 and 12 are provided with countless holes for discharging gas, and the holes communicate with a gas supply unit (not shown) through a gas pipe (not shown). Further, each gas levitation stage 11, 12 is provided with a hole through which a pin 53 of a substrate support device 50 described later passes.
[0022]
The substrate horizontal feeding device 20 is a device for horizontally transporting the substrate that has floated on the substrate gas levitation device from the rear gas levitation stage 11 to the front gas levitation stage 12. A mechanism 22, a substrate horizontal feed base feed mechanism 23, a substrate horizontal feed base drive mechanism 24, and substrate posture determination mechanisms 25 and 26 are provided. The substrate horizontal feed base 21 is a structure straddling the substrate gas levitation apparatus 10 in the left-right direction, and is fixed to the surface plate 90 so as to be movable in the front-rear direction. The substrate gripping mechanism 22 is a mechanism that can grip the front end portion of the substrate that has gas floated on the rear gas levitation stage 11 or the front gas levitation stage 12, and is supported by the substrate horizontal feed base 21. The substrate horizontal feed base feed mechanism 23 is a mechanism for moving the substrate horizontal feed base 21 in the front-rear direction, and includes a linear guide and a feed screw. The substrate horizontal feed base driving mechanism 24 is a mechanism for driving the substrate horizontal feed base 21 via the substrate horizontal feed base feed mechanism 23, and has a motor and a motor driver connected to a feed screw by a torque joint. The substrate posture determining mechanisms 25 and 26 are mechanisms for adjusting the posture of the substrate that has floated on the rear gas levitation stage 11.
[0023]
The laser optical system 30 is a mechanism for oscillating a laser for laser annealing the substrate, guiding the laser beam 4 and irradiating the substrate through the gap from the lower side of the substrate gas levitation apparatus 10. An oscillator 31, a 45-degree mirror 32, a linear beam shaping optical system 33, and a laser beam guiding optical system 34 are included. The laser transmitter 31 is a device that oscillates a laser, and is provided in front of the substrate gas levitation apparatus 10. The oscillated laser beam 4 is bent 45 degrees by a 45-degree mirror 32 and guided under the front gas levitation stage 12. The linear beam shaping optical system 33 expands the width of a laser beam having a spot-like cross section horizontally by the optical system to produce a linear laser beam having a linear cross section (for example, a thickness of 50 to 70 microns and a width of 300 mm). It is an optical system that outputs and is provided below the front gas levitation stage 12. The laser beam guiding optical system 34 is an optical system that guides the horizontally incident linear laser beam by the optical system, and irradiates the lower surface of the substrate that floats on the substrate gas floating device 10 from below the gap, The 45 degree mirror 35, the condensing lens 36, the prism 37, and the common mount 39 are arrange | positioned under the said clearance gap. The 45-degree mirror 35 is a mirror that reflects the horizontally incident linear laser beam vertically upward, and is provided below the gap. The condenser lens 36 is a cylindrical lens for reducing the thickness dimension while maintaining the width dimension of the linear laser beam, and is provided above the 45-degree mirror 35 below the gap. The prism 37 is a device for tilting the linear laser beam incident vertically upward backward by a predetermined angle (for example, 30 degrees). It is provided in the gap. The common frame 39 is a structure that integrally supports the linear beam shaping optical system 33, the 45 ° mirror 35, the condenser lens 36, and the prism 37, and is supported by the surface plate 90.
[0024]
The substrate height adjusting device 40 is a mechanism that maintains a gap between the lower surface of the substrate 2 and the upper surface of the gas levitation stage in the vicinity of the gap at a constant distance, and includes a plurality of gas bearings 51 and a control mechanism (not shown). Have The gas bearing 51 is a sintered metal having a cylindrical shape and a hole in the center. Gas bearings arranged in a line in the left-right direction are respectively placed before and after the gap with a space through which the linear laser beam passes in the middle. The gas bearing 51 communicates with a gas supply pipe for blowing gas from the outer peripheral portion and a gas suction pipe for sucking gas from the central hole. A flow rate adjusting valve (not shown) is provided in the gas supply pipe and the gas suction pipe, and the flow rate can be adjusted by a command from the control device. The control device has a gap sensor for measuring the dimension of the gap, and can control the flow rate adjusting valve so as to make the output of the gap sensor constant.
[0025]
The substrate support device 50 is a mechanism for delivering the substrate 2 between a substrate loader 60 and a substrate gas levitation device 10 described later, and includes a rear substrate support device 51 and a front substrate support device 52. The rear substrate support device 51 is disposed below the rear gas levitation stage 11, and the front substrate support device 52 is disposed below the front gas levitation stage 12. Each of the substrate support devices 51 and 52 has a plurality of pins 53 and a pin lifting mechanism 54. The plurality of pins 53 are rod-like structures that support the substrate, stand vertically, and have their tips on the same plane. The plurality of pins 53 pass through holes provided in the gas levitation stages 11 and 12. The pin elevating mechanism 54 is a pantograph lifter that elevates and lowers the pin 53, and is provided below the gas levitation stages 11 and 12. When the lifting mechanism 54 lowers the pin that supports the substrate 2 at the tip of the pin 53, the substrate 2 can be transferred from the pin 53 to the gas levitation stages 11 and 12. Further, when the lifting mechanism 54 raises the pin 53, the gas floating substrate 2 can be transferred from the gas floating stage 11, 12 to the pin 53.
[0026]
The substrate loader 60 is a mechanism for taking out a substrate from a cassette 3 (to be described later), delivering it to the rear substrate support device 51, receiving the substrate 2 from the front substrate support device 52, and putting it in the cassette 3. And have. The atmospheric robot 61 has a main body movable in the front-rear direction on the left side of the substrate gas levitation apparatus 10 and a holding arm supported on the main body. The holding arm supports the lower surface of the substrate. Deliver to and from the support device 50. The turntable 65 is a mechanism that transfers the substrate to and from the atmospheric robot 61 and rotates the substrate to change its direction.
[0027]
The cassette station 70 is a station in which the substrate cassette 3 is placed, and delivers the substrate cassette 3 through the pre-process and post-process and the AGV.
The operation panel 80 is a control panel for operating the laser annealing apparatus.
The surface plate 90 supports the substrate gas floating device 10, the substrate horizontal feeding device 20, the laser beam guiding optical system 34 of the laser optical system 30, and the substrate height adjusting device 40.
[0028]
Hereinafter, the operation of the laser annealing apparatus will be described according to the substrate processing steps.
First, a plurality of substrates 2 are placed in the substrate cassette 3, the cassette station 70 is placed, and an empty substrate cassette 3 is placed in the cassette station 70. A semiconductor film to be annealed is provided on the surface of the substrate 2 and is arranged in the substrate cassette 3 with the surface facing up.
[0029]
(Extraction Step) The atmospheric robot 61 takes out the horizontal substrate 2 from the substrate cassette 3 and places it on the turntable 65.
[0030]
(Rotating step) The turntable 65 rotates the substrate 2 horizontally by 90 degrees.
[0031]
(Loading Step) The atmospheric robot 61 takes out the horizontal substrate 2 from the turntable 65 and puts it on the rear substrate support device 51. At this time, the rear substrate support device 51 raises and lowers the pins 53, and the substrate 2 is supported by the tips of the pins 53.
[0032]
(Alignment process) The substrate posture determination devices 25 and 26 press both sides of the substrate 2 and press corners to adjust the posture of the substrate 2.
[0033]
(Floating process) The rear substrate support device 51 lowers the pin 53 and places the substrate 2 on the rear gas floating stage 11. At this time, the rear gas levitation stage 11 blows out gas from the upper surface thereof, so that the substrate 2 floats.
[0034]
(Fine Alignment Step) The substrate horizontal feed base 21 is fed backward by the substrate horizontal feed base feed mechanism 23, and the substrate gripping mechanism 22 contacts the front end of the substrate 2. The substrate posture determining device 25 presses both sides of the substrate 2 and the substrate posture determining device 26 pushes the substrate 2 forward to finely adjust the posture of the substrate 2.
[0035]
(Gripping Step) The substrate gripping mechanism 22 grips the front end of the substrate 2.
[0036]
(Laser irradiation step) The laser shutter of the laser oscillator 31 is opened. The laser beam 4 enters the linear beam shaping optical system 33 via the 45 degree mirror 32. A linear beam is emitted from the linear beam shaping optical system 33 and enters the laser beam guiding optical system 34. The linear laser beam is redirected upward by a 45 degree mirror 35, condensed by a condenser lens 36, tilted rearward by a predetermined angle (for example, 30 degrees) by a prism 37, and irradiated onto the substrate 2. The The substrate horizontal feed base 21 is fed forward by the substrate horizontal feed stand feed mechanism 23, and the substrate 2 gripped by the substrate gripping mechanism 22 is transported forward at a predetermined speed. The substrate height adjusting device 40 maintains and controls the height of the portion that passes through the space portion of the substrate. The linear laser beam 4 is irradiated from the back side of the substrate 2, passes through the inside of the substrate 2, and anneals the semiconductor film on the surface of the substrate. When the substrate 2 moves forward, the laser shutter of the laser oscillator 31 is closed.
[0037]
(Floating stop step) The front substrate support device 52 raises the pin 53. The substrate 2 is supported and raised by the pins 53 and is supported by the pins 53.
[0038]
(Unloading step) The atmospheric robot 61 receives the substrate 2 on the front substrate support device 52 and places it on the turntable 65.
[0039]
(Rotating step) The turntable 65 rotates the substrate 2 horizontally by 90 degrees.
[0040]
(Returning Step) The atmospheric robot 61 takes out the horizontal substrate 2 from the turntable 65 and places it on the substrate cassette 3.
[0041]
By sequentially repeating the steps, the processing of the substrates 2 arranged in the substrate cassette 3 is completed.
[0042]
In order to perform a new laser annealing method on a substrate using the laser annealing apparatus of the above-described embodiment, a substrate that has been horizontally leveled with a surface facing upward may be stacked on a substrate cassette and placed in a cassette station as in the past. . The laser annealing apparatus of the above-described embodiment supports and handles the back surface of the substrate with the back surface facing down, and laser-irradiates the back surface with laser from below to laser anneal the semiconductor on the surface of the substrate. Since the back surface of the substrate is supported and handled, contamination of the semiconductor on the surface of the substrate can be prevented.
Accordingly, as disclosed in Japanese Patent Application No. 2001-021032, the thin film transistor formed on the substrate is irradiated with laser light that can be transmitted through the substrate from the substrate side to activate polysilicon constituting the thin film transistor. A new laser annealing method can be implemented. As a result, since the laser light passes through the substrate, it can be irradiated through the substrate from the substrate side, and all the polysilicon constituting the TFT (thin film transistor) can be annealed. Thereby, the activity of silicon after doping can be maximized, and an excellent semiconductor film having a short processing time and less risk of substrate distortion can be obtained.
Further, since the linear beam irradiated vertically from the lower side is irradiated from the back surface of the substrate through the gap and tilted by a predetermined angle by the prism, the laser beam that has passed through the substrate has a predetermined surface and a predetermined surface. The semiconductor film is irradiated at an angle crossing.
Therefore, as disclosed in Japanese Patent Application No. 2001-020893, an apparatus can be realized in which the optical axis of the laser light on the irradiation surface of the substrate intersects the irradiation surface orthogonal axis of the substrate at a predetermined angle. As a result, the optical axes of the reflected light on the upper surface of the semiconductor film and the reflected light on the lower surface of the semiconductor are shifted, so that mutual interference due to the path difference can be prevented, and the intensity distribution of the reflected laser light is uneven. There is no unevenness in the resistivity distribution of the semiconductor on the crystallized substrate, the crystal grain size distribution or the mobility distribution of the crystallized semiconductor, and a semiconductor having better characteristics than the present state can be obtained.
[0043]
The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.
[0044]
【The invention's effect】
As described above, the laser annealing apparatus for irradiating the substrate with laser while transporting the substrate of the present invention in the horizontal direction has the following effects.
If the substrate having the semiconductor film is placed on the gas levitation stage with the surface facing upward, the substrate floats on the front gas levitation stage and the rear gas levitation stage, and is sent horizontally across the gap, from the gap. Since the lower surface is irradiated with the laser beam and the laser light is transmitted through the substrate, the surface can be irradiated through the substrate from the back side. As a result, the activity of the semiconductor film can be maximized, the processing time is short, and there is little risk of distortion of the substrate.
Further, since the reflector can reflect the laser beam irradiated upward from the gap, the laser beam that has passed through the substrate can be reflected downward and irradiated onto the surface of the substrate again, so that the laser energy can be used without waste. .
The linear beam intersects the orthogonal line of the surface of the substrate at a predetermined inclination angle and irradiates the substrate, and the laser beam incident from the back surface of the substrate is reflected by the lower surface and the upper surface of the semiconductor film layer on the substrate. However, since different paths are used, mutual interference of a plurality of reflected beams having path differences can be prevented.
In addition, the substrate support device can horizontally support the lower surface of the substrate, and can move the substrate up and down above the gas levitation stage. The substrate can be transferred to and from the gas levitation stage. The substrate can be handled in a normal handling posture and transferred to and from the gas levitation stage.
Further, the substrate height adjusting device can adjust the height of the lower surface of the substrate in the vicinity of the gap, and the beam shape on the substrate of the laser beam irradiated upward from the gap is stabilized. The characteristics of the semiconductor film are stabilized.
Also, if the substrate having a semiconductor film is placed in the substrate cassette with the surface facing upward, the substrate surface is handled with the surface facing up, and the semiconductor film formed on the substrate is irradiated with laser light from the back surface, so that the laser light is emitted. The semiconductor film can be activated by irradiating through the substrate from the back side. All surfaces constituting the semiconductor film can be annealed, and the activity of the semiconductor film can be maximized. In addition, since the optical axis of the laser beam on the irradiation surface of the substrate intersects with the irradiation surface orthogonal axis of the substrate at a predetermined angle, the optical axes of the reflected light on the semiconductor film upper surface and the reflected light on the semiconductor lower surface are shifted, Mutual interference due to the path difference does not occur, and the intensity distribution of the reflected laser light is uneven. The resistivity distribution of the semiconductor on the activated substrate, the crystal grain size distribution and movement of the crystallized semiconductor, etc. A semiconductor with good characteristics can be obtained without unevenness in the degree distribution.
Accordingly, the present invention provides an excellent laser annealing apparatus that is suitable for the implementation of a new laser annealing method, can maximize the activity of a semiconductor film, has a short processing time, and has a low risk of substrate distortion. Can do.
[0045]
[Brief description of the drawings]
FIG. 1 is a plan view of an embodiment of the present invention.
FIG. 2 is a side sectional view of an embodiment of the present invention.
FIG. 3 is a partial detail view of FIG. 2;
FIG. 4 is a configuration diagram of a conventional laser annealing apparatus.
FIG. 5 is a manufacturing process diagram of a low-temperature polysilicon TFT.
[Explanation of symbols]
1 Laser annealing equipment
2 Substrate
3 Substrate cassette
4 Laser beam
10 Gas levitation stage
11 Back gas levitation stage
12 Front gas levitation stage
20 Substrate horizontal feeding device
21 Horizontal feed base
22 Substrate gripping mechanism
23 Substrate horizontal feed base feed mechanism
24 Substrate horizontal feed base drive mechanism
25 Board left / right posture determination mechanism
26 Substrate front and rear posture determination mechanism
30 Laser optics
31 Laser oscillator
32 45 degree mirror
33 Linear beam shaping optics
34 Laser beam guidance optics
35 45 degree mirror
36 condenser lens
37 prism
38 reflector
39 frame
40 Substrate height adjustment device
41 Gas bearing
50 Substrate support device
51 Rear substrate support device
53 pins
54 pin lifting mechanism
60 Substrate loader
61 atmospheric robot
65 turntable
70 cassette station
80 control panel
90 surface plate

Claims (5)

A laser annealing apparatus irradiating a laser beam to the substrate while transporting the substrate in a horizontal direction,
A gas levitation apparatus that can the substrate blowing gas from an upper surface and a front gas floating stage and a rear gas levitation stage arranged in the transport direction across a predetermined gap is gas levitation,
A horizontal feed device for feeding a horizontal direction the substrate was gas floating across the gap,
Laser annealing apparatus characterized by comprising a laser optical system for irradiating upward the laser beam through the gap. In claim 1 ,
Provided above the gap, Relais Zaaniru device comprising a reflector capable of reflecting the laser beam emitted from the lower downward. In claim 1 or claim 2,
Said laser beam, characterized and, Relais Zaaniru device to be a linear beam that intersects at a predetermined angle with respect to the substrate orthogonal axes. In any one of Claims 1 thru | or 3,
A plurality of pins that can horizontally support the lower surface of the substrate;
Features and, Relais Zaaniru device further comprising a substrate supporting device having a pin lift mechanism capable of raising and lowering the plurality of pins through said gas floating stage. In any one of Claims 1 thru | or 4,
Disposed in said gap, a gas bearing for supporting the substrate floating the substrate lower surface by blowing gas from the upper surface,
Features and, Relais Zaaniru device further comprising a substrate height adjustment device and a control device for adjusting the height of the lower surface of the substrate by adjusting the blowout amount of the gas.

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