JP4094093B2 - Laser annealing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser annealing apparatus for crystallizing an amorphous thin film by irradiating it with laser light.
[0002]
[Prior art]
The laser annealing treatment apparatus is used for manufacturing a polycrystalline semiconductor thin film and the like, and in the above manufacturing, the amorphous semiconductor thin film is irradiated with laser light to be polycrystalline.
An example of a conventional laser annealing apparatus will be described with reference to FIG. 3. A movable mounting table 21 for horizontally mounting a substrate 1 on which an amorphous semiconductor thin film is formed on an insulating plate is movably disposed. 1 is stored in a stacked state on a substrate storage cassette 23 arranged close to the movable mounting table 21 in order to increase productivity. A substrate transfer device 25 that moves the substrate 1 from the cassette 23 to the movable mounting table 21 is disposed between the substrate storage cassette 23 and the movable mounting table 21.
The laser annealing apparatus is provided with an excimer laser irradiation apparatus 26 that irradiates the substrate 1 with laser light 27 from above. The laser irradiation apparatus 26 reflects the laser light by reflecting a laser output unit 26a. It has mirrors 26b ₁ , 26b ₂ , 26b _{3 for} deflecting and a cylindrical lens 26c for condensing the laser beam. Since the mirror 26b generally emits laser light output from a laser irradiation device horizontally, the traveling direction of the laser light is converted (deflected) into a direction perpendicular to the substrate by reflection by the mirror. It is provided for.
[0003]
Laser annealing using the above apparatus is performed, for example, according to the following procedure.
The unprocessed substrate 1 stored in the substrate storage cassette 23 is taken out by the substrate transfer device 25 and mounted on the movable mounting table 21 in a horizontal state. Next, the movable mounting table 21 is moved so that the laser beam 27 is positioned at the irradiation start point of the substrate 1, and the laser beam 27 is generated from the excimer laser irradiation device 26. After the laser beam 27 is output from the laser output unit 26a, the laser beam 27 is deflected three times by reflection at the mirror 26b, further condensed by the cylindrical lens 26c, and irradiated on the surface of the substrate 1 from above the substrate 1 substantially perpendicularly. The By moving the movable mounting table 21 in this state, the entire surface of the amorphous semiconductor thin film on the substrate 1 can be scanned with a laser beam. By this laser light irradiation, the amorphous semiconductor thin film on the substrate 1 is crystallized.
The substrate 1 processed as described above is taken out from the movable mounting table 21 by the substrate transfer device 25 and stored again in the cassette 23, and another unprocessed substrate 1 is taken out from the cassette 23 and the same processing as above is repeated. Do.
[0004]
[Problems to be solved by the invention]
However, the conventional laser annealing apparatus described above has the following problems.
(1) The optical axis shift occurs due to the installation of the mirror, and the energy loss of the laser beam occurs.
(2) Since the substrate is placed horizontally, particles are likely to adhere to the substrate surface.
(3) A mounting table is required to eliminate deflection when the substrate is installed and maintain the parallelism of the substrate, but the substrate is placed on it, so the back of the substrate contacts the mounting table and is damaged. It easily causes static electricity and causes various problems.
The basic object of the present invention is to solve the above-mentioned problems, and it is possible to avoid laser beam energy loss and avoid contact with a mounting table, etc., so that annealing is performed without degrading quality. An object of the present invention is to provide a laser annealing apparatus capable of achieving the above.
[0005]
[Means for Solving the Problems]
The laser annealing apparatus of the present invention for solving the aforementioned problems is a substrate storage cassette plurality housed in a state where the substrate vertically, is connected to the substrate storage cassette, the vertical or horizontal substrate laser beam irradiation position Cassette driving means for moving the substrate storage cassette in the parallel direction of the substrates until it is positioned in a direction, and substrate holding means for moving the substrate up and down or laterally to take it out of the substrate storage cassette and cross the laser beam And laser irradiation means for irradiating the substrate moved by the substrate holding means without deflecting the laser light by reflection after outputting the laser light.
[0006]
The field of use of the laser annealing apparatus of the present invention is not particularly limited and can be used in various fields. For example, it is useful as a laser annealing apparatus used for forming a polycrystalline silicon thin film.
In addition, the laser beam used in the present invention is not particularly limited with respect to the generation method, wavelength, cross-sectional shape, etc., and can have any optical system on the assumption that no deflection by reflection is performed. It is.
Further, the substrate holding means is not particularly limited as long as it can hold the substrate in a vertical state, and the holding structure is not particularly limited, but it is desirable to hold the substrate with a small contact area. Note that it is not essential to stand the substrate upright for this holding, but it is desirable to hold the substrate in an upright state from the standpoint of stably holding the substrate without bending or the like. Further, the holding means only needs to move in a direction intersecting with the laser beam in order to scan the laser beam on the substrate, and the direction may be the vertical direction or the horizontal direction depending on the design of the apparatus. However, in this movement, it is desirable to keep the optical path length of the laser light constant, and when the substrate is upright, it is desirable to move in the direction perpendicular to the laser light.
[0007]
The substrate may be supplied in a vertical state to the substrate holding means, or the substrate supplied horizontally may be rotated by the holding means to be vertical. In order to increase productivity, a plurality of substrates are stored in a storage cassette, and the substrates are supplied from the cassette to the substrate holding means . In this case, if the substrate is stored vertically in the storage cassette and supplied to the substrate holding means as it is, the substrate can be transported more efficiently, and the substrate may be damaged. Can also prevent.
[0008]
That is, according to the present invention, the substrate can be irradiated with the laser beam vertically, so that the substrate can be irradiated with the laser beam without being deflected by reflection, and the optical axis of the laser beam is prevented from shifting due to reflection. Can do. In addition, since the substrate is placed vertically during annealing, it is difficult for particles to adhere to the surface, and furthermore, generation of scratches and static electricity due to contact with the mounting table can be avoided, so that the substrate quality is kept good. Is possible.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG. Note that the present invention is not limited thereby.
A plurality of substrates 1 having an amorphous thin film formed thereon are stored in a standing state in a substrate storage cassette 2, and the cassette 2 can be moved in the substrate storage cassette 2 in the parallel direction of the substrates 1. Thus, the cassette driving means 3 is connected. A substrate holding means 4 is disposed below the substrate storage cassette 2. The substrate holding means 4 is composed of a driving portion 4a, an upwardly extending elastic member 4b, and a holding portion 4c provided at the tip of the elastic member 4b. The holding portion 4 c is formed with a storage recess so as to hold the bottom portion of the substrate 1. On the other hand, a slit 2a through which the holding portion 4c can be penetrated is formed for each substrate 1 at the bottom of the cassette 2 along the bottom direction of the substrate 1. It is supported without falling by placing it on the bottom. Further, a laser output unit 5a is disposed on the side of the cassette 2 so as to irradiate the laser beam on the upper side of the cassette 2, and a cylindrical beam that condenses the laser beam in the output direction of the laser output unit 5a. A lens 5b is disposed, and the laser output unit 5a and the cylindrical lens 5b constitute laser irradiation means.
[0010]
An annealing process using the above apparatus will be described below.
Of the substrates 1 stored in the substrate storage cassette 2, the cassette driving means 3 is operated to move the cassette 2 in the horizontal direction so as to take out the desired substrate, and the desired substrate 1 is positioned above the holding portion 4c. Let At this time, the holding portion 4c is lowered to a position where the elastic member 4b of the substrate holding means 4 is sufficiently contracted so as not to interfere with the cassette 2.
After the desired substrate 1 is positioned on the holding portion 4c as described above, the driving portion 4a is operated to extend the expansion / contraction member 4b, and the bottom of the substrate 1 is placed in the holding portion 4c at the tip. To raise. The substrate 1 is raised until reaching the laser beam irradiation position (initial position) by the laser irradiation means.
[0011]
When the laser beam 6 is irradiated from the laser output unit 5a in a state where the substrate 1 is disposed at the laser beam irradiation position, the laser beam 6 is incident on the cylindrical lens 5b without being deflected by reflection, and is condensed by the lens 5b. Then, the substrate 1 is irradiated. In this state, when the expansion / contraction member 4b is expanded / contracted by the driving unit 4a, the substrate 1 is raised or lowered accordingly, so that the laser beam 6 is relatively scanned, and the surface of the substrate 1 is amorphous. The thin film is crystallized by annealing.
The crystallized substrate 1 is lowered by contracting the expansion / contraction member 4b by the operation of the drive unit 4a, and is stored again in the substrate storage cassette 2, and the holding by the holding unit 4c is released. Thereafter, in order to process another substrate, the cassette driving means 3 is operated and the above operation is repeated, whereby the annealing process can be continuously performed on the plurality of substrates.
[0012]
In the above embodiment, the laser beam is scanned by moving the substrate up and down. However, as shown in FIG. 2, the substrate 1 stored in the substrate storage cassette 12 is placed in the substrate holding unit 14. Annealing treatment can also be performed by moving the holding portion 14c in the lateral direction. In this case, the laser light is irradiated in a direction penetrating the paper surface of FIG. The substrate storage cassette 12 is slidably mounted on the cassette table 15 and is moved in the parallel direction of the substrates 1 by the cassette driving means 13.
[0013]
In each of the above embodiments, the atmosphere of the annealing process has not been described. For example, the apparatus except for the laser irradiation means is accommodated in an annealing chamber, and the annealing chamber is adjusted to a specific atmosphere for annealing. In addition, the laser annealing apparatus may be provided with an apparatus for preheating the substrate or heating the substrate at the time of annealing.
In each of the above embodiments, the direction of movement of the substrate during laser light irradiation is one direction. However, for example, scanning of laser light may be performed by combining lateral movement and vertical movement. However, if the laser beam is a line beam, the entire substrate surface is scanned by moving the substrate in one direction, and movement in a plurality of directions is not necessary. In this case, the arrangement of the substrate and the direction of the line beam are determined so that the moving direction of the substrate is orthogonal to the long side of the line beam.
In each of the above embodiments, the direction in which the substrate is taken out from the cassette and the direction in which the substrate moves during laser light irradiation are matched . Changing the take-out direction and the moving direction, the movement mechanism is complicated, and take-out direction from the cassette, Ru match to the moving direction of the substrate when being irradiated with laser light. More preferably, the scanning is performed by pushing or pulling out the substrate from the cassette by the substrate holding means and moving the substrate along that direction.
[0014]
【The invention's effect】
As described above, according to the laser annealing apparatus of the present invention, a substrate storage cassette that stores a plurality of substrates in a vertical state, and the substrate is connected to the substrate storage cassette, and the substrate is vertically aligned with a laser beam irradiation position. Alternatively, cassette driving means for moving the substrate storage cassette in the parallel direction of the substrate until it is positioned in the horizontal direction, and substrate holding for moving the substrate up and down or laterally and taking it out of the substrate storage cassette and intersecting with the laser beam And laser irradiation means for irradiating the substrate moved by the substrate holding means without deflecting the laser light by reflection after outputting the laser light, so that energy loss due to reflection of the laser light is reduced. It can be avoided, and the quality of the particles can be adhered to the substrate during annealing, or damage and static electricity can be generated. It is also inevitable to deteriorate, it is possible to obtain a high quality annealing the substrate efficiently.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a laser annealing apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a laser annealing apparatus showing another embodiment.
FIG. 3 is a cross-sectional view of an essential part showing an example of a conventional laser annealing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Substrate storage cassette 3 Cassette drive means 4 Substrate holding means 4a Drive part 4b Telescopic member 4c Holding part 5a Laser output part 5b Cylindrical lens 6 Laser light 12 Substrate storage cassette 13 Cassette drive means 14 Substrate holding means 14c Holding part

Claims (1)

A substrate storage cassette that stores a plurality of substrates in a vertical state, and is connected to the substrate storage cassette, and stores the substrate in the parallel direction of the substrates until the substrate is positioned in the vertical or horizontal direction of the laser light irradiation position. Cassette driving means for moving the cassette, substrate holding means for moving the substrate in the vertical direction or lateral direction to take it out of the substrate storage cassette and intersecting with the laser light, and outputting the laser light and then reflecting the laser light by reflection And a laser irradiation means for irradiating the substrate moved by the substrate holding means without being deflected.

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