JP3650943B2 - Laser annealing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser annealing processing apparatus, and more particularly to a laser annealing processing apparatus capable of always performing appropriate annealing without excess or deficiency even if there are variations in objects to be processed. The laser annealing apparatus of the present invention is particularly useful for forming a large area large grain polycrystalline silicon thin film.
[0002]
[Prior art]
FIG. 5 is a longitudinal sectional view of an essential part of an example of a conventional laser annealing apparatus.
This laser annealing processing apparatus 500 includes an aluminum vacuum chamber 1 and a moving mounting table 2 that moves on a base B installed in the vacuum chamber 1 and on which an object to be processed M is mounted. The resistance wire 3 embedded in the upper surface of the movable mounting table 2 for preheating the object to be processed M, and the UV reflection preventing film (AR coating) provided on the quartz glass plate on both surfaces of the ceiling portion 1a of the vacuum chamber 1 A laser introducing window 5 for forming a laser beam, an excimer laser irradiating device 6 for irradiating a laser beam R substantially vertically downward through the laser introducing window 5, and a gate valve for introducing the workpiece M into the vacuum chamber 1. S2 and a gate valve S3 for leading the workpiece M from the vacuum chamber 1 are provided. 1b is an exhaust port for evacuation. The object to be processed M is obtained by forming an amorphous semiconductor thin film M1 on an insulating substrate M2.
[0003]
Laser annealing is performed according to the following procedure.
{Circle around (1)} The gate valve S2 is opened, an unprocessed object M is placed on the movable mounting table 2, and the gate valve S2 is closed.
(2) The vacuum chamber 1 is evacuated from the exhaust port 1b, and the vacuum chamber 1 is evacuated to a high vacuum of 10 ⁻² to 10 ⁻⁶ Torr (or filled with nitrogen gas). Next, the resistance wire 3 is energized to preheat the workpiece M to about 400 ° C. Further, the movable mounting table 2 is moved so that the laser irradiation portion P is positioned at the irradiation start point of the workpiece M. Then, the laser beam R is generated from the excimer laser irradiation device 6. The laser beam R is introduced into the vacuum chamber 1 through the laser introduction window 5 and irradiated on the surface of the workpiece M substantially perpendicularly. In this state, the movable mounting table 2 is moved, and the entire surface (for example, 300 mm × 300 mm) of the amorphous semiconductor thin film M1 of the object to be processed M is scanned with a laser irradiation portion P having a small area (for example, 0.4 mm × 150 mm). . Thereby, the amorphous semiconductor thin film M1 can be crystallized.
{Circle around (3)} The gate valve S3 is opened, the processed object M is removed from the movable mounting table 2, and the gate valve S3 is closed.
[0004]
[Problems to be solved by the invention]
The conventional laser annealing apparatus 500 has a problem in that it is impossible to determine whether or not annealing is appropriate unless the workpiece M is taken out of the vacuum chamber 1 and analyzed.
Further, the film thickness and properties of the amorphous semiconductor thin film M1 vary. For this reason, in the conventional laser annealing apparatus 500, if the irradiation intensity and irradiation timing of the laser beam R and the movement speed and movement timing of the movable mounting table 2 are kept constant, depending on the workpiece M, the annealing is performed. There is a problem that it causes excess and deficiency.
Accordingly, a first object of the present invention is to provide a laser annealing processing apparatus that can know whether annealing is appropriate or not during annealing.
A second object of the present invention is to provide a laser annealing processing apparatus capable of always performing appropriate annealing without excess or deficiency even if the objects to be processed vary.
[0005]
[Means for Solving the Problems]
In the first aspect, the present invention irradiates the laser beam (R) for laser annealing treatment from the outside through the laser introduction window (5) to the object to be processed (M) placed in the sealed container (1). Laser irradiation means (6) and a movable mounting table on which the object to be processed (M) is moved so as to scan a large area of the object to be processed (M) with a laser irradiation part (P) having a small area (2), the movable mounting table (2) has a workpiece (M) mounted on the upper surface thereof, and the laser introduction window (5) is hermetically sealed. Provided obliquely on the ceiling (1a) of the container (1), and irradiates the laser beam (R) for laser annealing treatment obliquely from above to the object to be processed (M) through the laser introduction window (5). And the reflection that is regularly reflected by the object to be processed (M). Installed Za light intensity measuring means for measuring the intensity of (L) (9) in the closed container (1) inside, based on the intensity of the reflected laser beam measured by the light intensity measuring means (9) (L) The laser annealing apparatus (100) is characterized in that the progress of the laser annealing process is discriminated.
In the laser annealing apparatus (100) according to the first aspect, the laser beam (R) for laser annealing is irradiated on the object (M) from an oblique direction, and the reflected laser light is regularly reflected in the reverse oblique direction. The intensity of (L) is measured by the light intensity measuring means (9). Here, the reflectance of the object (M) is changed by the progress of the laser annealing process, the progress of the intensity by laser annealing of the reflected laser light measured by the light intensity measuring means (9) (L) is I understand. For example, the reflectance of the amorphous semiconductor thin film (M1) is relatively small, but the reflectance becomes relatively large when crystallized, so the intensity of the reflected laser light (L) measured by the light intensity measuring means (9) is It increases with the progress of crystallization and does not change when crystallization is completed. Therefore, by determining the progress of the laser annealing process based on the measured intensity of the reflected laser beam (L), it is possible to know whether the laser annealing process is appropriate during the laser annealing process . And it becomes possible to complete an appropriate laser annealing process , without taking out a to-be-processed object (M) from an airtight container (1), and high throughput is obtained.
[0006]
In addition, in order to irradiate laser beam (R) to a to-be-processed object (M) from the diagonal direction, it is the ceiling part (1a) of airtight container (1), and the position remove | deviated from the perpendicular | vertical upper direction of a laser irradiation part (P) Is provided with a laser introduction window (5). For this reason, a transpiration substance is generated from the object to be processed (M) during annealing, and it adheres to the wall of the ceiling (1a) of the hermetic container (1) and vertically above the laser irradiation part (P). The laser introduction window (5) is not dirty. Accordingly, it is possible to prevent the energy of the laser beam (R) introduced from the laser introduction window (5) from being attenuated by the transpiration substance from the object to be processed (M).
[0007]
In addition, since the laser beam (R) is irradiated to the object (M) from an oblique direction, the reflected laser beam (L) reflected by the object (M) is reflected from the ceiling (1a) of the sealed container (1). It is also possible to prevent reflection from being incident on the object to be processed (M) again and adversely affecting the annealing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited thereby.
[0009]
-First embodiment-
FIG. 1 is a cross-sectional view of an essential part of a laser annealing apparatus according to a first embodiment of the present invention.
The laser annealing apparatus 100 includes an aluminum vacuum chamber 1 and a movable mounting table 2 that moves on a base B installed in the vacuum chamber 1 and on which an object to be processed M is mounted. The resistance wire 3 embedded in the upper surface of the movable mounting table 2 for preheating the object to be processed M, and provided on the ceiling portion 1a of the vacuum chamber 1 at an inclination and on both sides of the quartz glass plate with an ultraviolet antireflection film ( In order to introduce the object M to be introduced into the vacuum chamber 1, the laser introduction window 5 formed with the AR coating), the excimer laser irradiation device 6 that irradiates the laser light R obliquely downward through the laser introduction window 5. A gate valve S2, a gate valve S3 for deriving the workpiece M from the vacuum chamber 1, and a light intensity for measuring the intensity of the reflected laser beam L specularly reflected by the workpiece M A constant unit 9, and a control unit 10 for controlling the laser irradiation means 6 or the moving table 2 based on the intensity of the light intensity measuring device the reflected laser beam L as measured by 9. 1b is an exhaust port for evacuation.
The object to be processed M is obtained by forming an amorphous semiconductor thin film M1 on an insulating substrate M2.
[0010]
Laser annealing is performed according to the following procedure.
{Circle around (1)} The gate valve S2 is opened, an unprocessed object M is placed on the movable mounting table 2, and the gate valve S2 is closed.
(2) The vacuum chamber 1 is evacuated from the exhaust port 1b, and the vacuum chamber 1 is evacuated to a high vacuum of 10 ⁻² to 10 ⁻⁶ Torr (or filled with nitrogen gas). Next, the resistance wire 3 is energized to preheat the workpiece M to about 400 ° C. Further, the movable mounting table 2 is moved so that the laser irradiation portion P is positioned at the irradiation start point of the workpiece M. Then, the laser beam R is generated from the excimer laser irradiation device 6. The laser light R is introduced into the vacuum chamber 1 through the laser introduction window 5 and is irradiated on the surface of the workpiece M from an oblique direction. In this state, the movable mounting table 2 is moved, and the entire surface (for example, 300 mm × 300 mm) of the amorphous semiconductor thin film M1 of the object to be processed M is scanned with a laser irradiation portion P having a small area (for example, 0.4 mm × 150 mm). . At this time, based on the intensity of the reflected laser beam L, the excimer laser irradiation device 6 is controlled to adjust the irradiation intensity and irradiation timing of the laser beam R, and the moving stage 2 is controlled to adjust the moving speed and moving timing. To do. Thereby, even if the film thickness and properties of the amorphous semiconductor thin film M1 vary, the amorphous semiconductor thin film M1 can be appropriately crystallized.
{Circle around (3)} The gate valve S3 is opened, the processed object M is removed from the movable mounting table 2, and the gate valve S3 is closed.
[0011]
FIG. 2 is a characteristic diagram of the reflectance of amorphous silicon a-Si and crystalline silicon C-Si.
The reflectance of amorphous silicon a-Si is smaller than that of crystalline silicon C-Si at any wavelength. Therefore, the intensity of the reflected laser beam L measured by the light intensity measuring device 9 is small for amorphous silicon a-Si, increases as crystallization progresses, and does not change at a large value when crystallization is completed.
Therefore, the control of the excimer laser irradiation device 6 and the movable mounting table 2 is performed so that the irradiation intensity of the laser beam R is increased or the irradiation time is lengthened while the intensity of the reflected laser beam L measured by the light intensity measuring device 9 is small. When the intensity of the reflected laser light L measured by the light intensity measuring device 9 increases, the irradiation intensity of the laser light R may be reduced or the irradiation time may be shortened.
[0012]
FIG. 3 is a convergence characteristic diagram of the movement speed when the irradiation intensity of the laser beam R is constant and the movement speed of the movable mounting table 2 is controlled.
The moving speed of the moving table 2 gradually increases from “0” at the irradiation start point, and converges to an optimum speed at which annealing can be performed without excess or deficiency.
[0013]
According to the laser annealing apparatus 100 described above, it is possible to always perform appropriate annealing without excess or deficiency without taking out the object M from the vacuum chamber 1 and even if the object M varies. Thus, quality and throughput can be improved.
Further, since the laser introducing window 8 is located at a position off the vertical upper side of the laser irradiation portion P, the laser introducing window 8 is hardly contaminated by the transpiration substance from the object M, and the energy of the laser beam R is reduced by the laser. Attenuation at the introduction window 8 can be prevented.
Further, since the reflected laser light L reflected by the object to be processed M is reflected by the ceiling portion 1a of the vacuum chamber 1 and does not enter the object to be processed M again, the reflected laser light L may adversely affect the annealing. Can be prevented.
[0014]
-Reference example-
FIG. 4 is a cross-sectional view of a main part of a laser annealing apparatus according to a reference example .
The laser annealing apparatus 200 includes an aluminum vacuum chamber 1 and a movable mounting table 2 that moves on a base B installed in the vacuum chamber 1 and on which an object to be processed M is mounted. The resistance wire 3 embedded in the upper surface of the movable mounting table 2 for preheating the object to be processed M, and the UV reflection preventing film (AR coating) provided on the quartz glass plate on both surfaces of the ceiling portion 1a of the vacuum chamber 1 A laser introducing window 5 for forming a laser beam, an excimer laser irradiating device 6 for irradiating a laser beam R substantially vertically downward through the laser introducing window 5, and a gate valve for introducing the workpiece M into the vacuum chamber 1. S2, a gate valve S3 for deriving the workpiece M from the vacuum chamber 1, and a light intensity measuring device 9 for measuring the intensity of the transmitted laser light transmitted through the workpiece M, And a control unit 10 for controlling the laser irradiation device 6 or the moving table 2 based on the intensity of the light intensity measuring device transmitting the laser beam measured by 9. 1b is an exhaust port for evacuation.
The object to be processed M is obtained by forming an amorphous semiconductor thin film M1 on an insulating substrate M2.
[0015]
Laser annealing is performed according to the following procedure.
{Circle around (1)} The gate valve S2 is opened, an unprocessed object M is placed on the movable mounting table 2, and the gate valve S2 is closed.
{Circle around (2)} The vacuum chamber 1 is evacuated from the exhaust port 1b, and the vacuum chamber 1 is evacuated to a high vacuum of 10 ⁻² to 10 ⁻⁶ Torr (or filled with nitrogen gas). Next, the resistance wire 3 is energized to preheat the workpiece M to about 400 ° C. Further, the movable mounting table 2 is moved so that the laser irradiation portion P is positioned at the irradiation start point of the workpiece M. Then, the laser beam R is generated from the excimer laser irradiation device 6. The laser beam R is introduced into the vacuum chamber 1 through the laser introduction window 5 and irradiated on the surface of the workpiece M substantially perpendicularly. In this state, the movable mounting table 2 is moved, and the entire surface (for example, 300 mm × 300 mm) of the amorphous semiconductor thin film M1 of the object to be processed M is scanned with a laser irradiation portion P having a small area (for example, 0.4 mm × 150 mm). . At this time, based on the intensity of the transmitted laser light, the excimer laser irradiation device 6 is controlled to adjust the irradiation intensity and irradiation timing of the laser light R, and the moving mounting table 2 is controlled to adjust the moving speed and moving timing. . Thereby, even if the film thickness and properties of the amorphous semiconductor thin film M1 vary, the amorphous semiconductor thin film M1 can be appropriately crystallized.
{Circle around (3)} The gate valve S3 is opened, the processed object M is removed from the movable mounting table 2, and the gate valve S3 is closed.
[0016]
According to the laser annealing apparatus 200 described above, it is possible to always perform appropriate annealing without excess or deficiency without removing the object M from the vacuum chamber 1 and even if the object M varies. Thus, quality and throughput can be improved.
However, since the laser introduction window 5 is located substantially vertically above the laser irradiation portion P, the laser introduction window 5 is contaminated by the vaporized material from the workpiece M, and the energy of the laser beam R is attenuated by the laser introduction window 5. There are things to do.
[0017]
【The invention's effect】
According to the laser annealing apparatus of the present invention, it is possible to always perform appropriate annealing without excess or deficiency without taking out the object to be processed from the sealed container, and even if the objects to be processed vary. And throughput can be improved.
Further, in order to irradiate the object to be processed with the laser beam from an oblique direction, a laser introduction window is provided at a position on the ceiling portion of the hermetic container and deviated from vertically above the laser irradiation portion. For this reason, a transpiration substance is generated from the object to be processed during annealing, and even if this is attached to the wall of the ceiling of the sealed container and vertically above the laser irradiation portion, the laser introduction window is not soiled. Therefore, the energy of the laser beam introduced from the laser introduction window can be prevented from being attenuated by the transpiration substance from the object to be processed.
Furthermore, since the laser beam is irradiated to the object to be processed from an oblique direction, the reflected laser beam reflected by the object to be processed is reflected by the ceiling portion of the sealed container and is incident on the object to be processed again. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a laser annealing apparatus according to a first embodiment of the present invention.
FIG. 2 is a characteristic diagram of reflectance of amorphous silicon a-Si and crystalline silicon C-Si.
FIG. 3 is a convergence characteristic diagram of movement speed when the irradiation intensity of laser light is constant and the movement speed of the movable mounting table is controlled.
FIG. 4 is a cross-sectional view of a main part of a laser annealing treatment apparatus according to a reference example .
FIG. 5 is a cross-sectional view of a main part of an example of a conventional laser annealing apparatus.
[Explanation of symbols]
100, 200, 500 Laser annealing treatment apparatus 1 Vacuum chamber 1a Ceiling part 1b Exhaust port 2 Moving mounting table 3 Resistance wire 5 Excimer laser introduction window 6 Excimer laser irradiation device 9 Light intensity measurement device 10 Control device B Base P Laser irradiation Part M Object M1 Amorphous semiconductor thin film M2 Insulating substrate

Claims (1)

Laser irradiation means (6) for irradiating laser beam (R) for laser annealing treatment from the outside to laser beam (R) through laser introduction window (5) to object (M) placed in hermetic container (1), and a small area Annealing process comprising a moving stage (2) on which the object to be processed (M) is moved so as to scan a large area of the object to be processed (M) with the laser irradiation part (P) of In the device
The movable mounting table (2) has a workpiece (M) mounted on the upper surface thereof, and the laser introduction window (5) is inclined to the ceiling (1a) of the sealed container (1). The laser beam (R) for laser annealing treatment is obliquely irradiated from above onto the object to be processed (M) through the laser introduction window (5 ) and is regularly reflected by the object to be processed (M). the intensity of the reflected laser light intensity measuring means for measuring the intensity of (L) (9) installed in the closed container (1) inside, the reflected laser beam measured by the light intensity measuring means (9) (L) was The laser annealing apparatus (100) characterized in that the progress of the laser annealing process is determined based on the above .

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