JP3513730B2 - Laser annealing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser annealing apparatus, and more particularly to a laser annealing apparatus capable of preventing a reduction in processing efficiency due to a substance evaporating from an object to be processed. The present invention relates to a laser annealing apparatus. The laser annealing apparatus of the present invention is particularly useful for forming a polycrystalline silicon thin film. 2. Description of the Related Art FIG. 3 is a longitudinal sectional view of an essential part of an example of a conventional laser annealing apparatus. The laser annealing apparatus 500 includes a vacuum chamber 1 made of aluminum.
A movable mounting table 2 which moves on a base B installed in the vacuum chamber 1 and on which an object to be processed M is mounted, and a quartz provided on a ceiling 1a of the vacuum chamber 1 A window 5 for laser introduction in which an ultraviolet antireflection film (AR coat) is formed on both surfaces of a glass plate, an excimer laser irradiation device 6 for irradiating a laser beam R through the window 5 for laser introduction, and the vacuum chamber 1 to be processed. A gate valve S2 for introducing the body M and a gate valve S3 for leading the workpiece M from the vacuum chamber 1 are provided. 1b is an exhaust port for evacuation (11). The object to be processed M is obtained by forming an amorphous semiconductor thin film M1 on an insulating substrate M2. The laser annealing is performed in the following procedure. (1) The gate valve S2 is opened, the unprocessed object M is placed on the movable mounting table 2, and the gate valve S2 is closed. (2) Evacuation from the exhaust port 1b of the vacuum chamber 1 (11)
And, 1 a vacuum chamber ^{1. 33~1. 33 × 10 -4} P
a . High vacuum (or filling with nitrogen gas). Next, the movable mounting table 2 is moved so that the laser irradiation part P is located at the irradiation start point of the object M. And
Laser light 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 irradiates the surface of the processing target M substantially vertically. 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 by the 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. (3) The gate valve S3 is opened, the processed object M is taken out of the movable mounting table 2, and the gate valve S3 is closed. When the surface of the object to be processed M is irradiated with the laser beam R, ablation occurs at the laser-irradiated portion P of the object to be processed M, and evaporative substances are generated. This evaporating substance rises substantially vertically upward as indicated by arrow J in FIG. Therefore, in the above-described conventional laser annealing apparatus 500, the evaporated substance adheres to the laser light passing portion of the laser introduction window 5, and contaminates the laser introduction window 5. Then, if the processing is repeated and the dirt on the laser introduction window 5 advances, the available energy of the laser light R decreases, and there is a problem that the processing efficiency decreases. In addition, there is a problem that the reflected laser light reflected by the object to be processed M is re-reflected due to contamination of the laser introduction window 5 and is irradiated again to the object to be processed M, thereby hindering favorable annealing. . Further, if the vacuum chamber 1 is opened and the laser introduction window 5 is frequently cleaned in order to avoid the above problem, there is a problem that the throughput is reduced and the production cost is increased. Therefore, an object of the present invention is to provide a laser annealing apparatus capable of preventing a reduction in processing efficiency due to a vaporized substance generated from an object to be processed. According to a first aspect of the present invention, there is provided a laser processing apparatus (M) placed in a closed container (1) through a laser introduction window (5) from outside. Light (R)
In the laser annealing apparatus for irradiating the laser beam, by providing a high-frequency plasma generating mechanism near the laser introduction window (5), the transpiration generated from the object to be processed (M) and adhered to the laser introduction window (5). A laser annealing apparatus (100) characterized in that a substance can be removed. In the laser annealing apparatus (100) according to the first aspect, the evaporated substance generated from the object (M) and adhered to the laser introduction window (5) is provided near the laser introduction window (5). By using the high-frequency plasma generation mechanism, the gas can be removed without opening the closed container (1). Therefore, it is possible to prevent the energy of the laser beam (R) introduced from the laser introduction window (5) from being reduced due to contamination of the laser introduction window (5), and to prevent a reduction in processing efficiency. The reflected laser light (L) reflected by the object (M) is re-reflected by the dirt on the laser introduction window (5), and the object (M) is reflected.
Is not irradiated again, and the annealing can be performed satisfactorily. Further, it is not necessary to frequently clean the laser introduction window (5) by opening the closed container (1), so that the throughput can be improved and the production cost can be reduced. An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited by this. First Embodiment 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. The laser annealing apparatus 100 includes a vacuum chamber 1 made of aluminum.
A movable mounting table 2 which moves on a base B installed in the vacuum chamber 1 and on which an object to be processed M is mounted, and a quartz provided on a ceiling 1a of the vacuum chamber 1 A laser introduction window 5 having an ultraviolet anti-reflection film (AR coat) formed on both sides of a glass plate, an excimer laser irradiation device 6 for irradiating a laser beam R substantially vertically downward through the laser introduction window 5, The high-frequency electrodes 9A and 9B provided above and below the window 5; a high-frequency generator 10; a gas supply pipe 12 for introducing a plasma source gas 13;
And a gate valve S3 for extracting the object M from the vacuum chamber 1.
Is provided. 1b is an exhaust port for evacuation (11). The object to be processed M is obtained by forming an amorphous semiconductor thin film M1 on an insulating substrate M2. The laser annealing is performed in the following procedure. (1) The gate valve S2 is opened, the unprocessed object M is placed on the movable mounting table 2, and the gate valve S2 is closed. (2) Evacuation from the exhaust port 1b of the vacuum chamber 1 (11)
And, 1 a vacuum chamber ^{1. 33~1. 33 × 10 -4} P
a . High vacuum (or filling with nitrogen gas). Next, the movable mounting table 2 is moved so that the laser irradiation part P is located at the irradiation start point of the object M. And
Laser light R is generated from the excimer laser irradiation device 6. The laser light R is introduced into the vacuum chamber 1 through the slit of the high-frequency electrode 9A and the laser introduction window 5, and is applied to the surface of the workpiece M substantially vertically through the slit of the high-frequency electrode 9B. . 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 by the laser irradiation portion P having a small area (for example, 0.4 mm × 150 mm). . (3) The gate valve S3 is opened, the processed object M is taken out of the movable mounting table 2, and the gate valve S3 is closed. When the annealing treatment is performed, a part of the amorphous semiconductor thin film M1 undergoes ablation, and the evaporating substance rises vertically above the laser-irradiated portion P and adheres to the laser introduction window 5. Therefore, the laser introduction window 5 becomes dirty while the annealing process is repeated, and the energy of the introduced laser beam R decreases. Further, the reflected laser light reflected by the object to be processed M is re-reflected by the contamination of the laser introduction window 5 and is re-irradiated to the object to be processed M, so that a good annealing process cannot be performed. Therefore, plasma cleaning is performed periodically. That is, the vacuum chamber 1 is vacuumed (0. About 133 Pa), supplying a plasma source gas 13 from the gas supply pipe 12, the high frequency generator 10, for example by generating a 13.56MHz high-frequency high-frequency electrode 9A, 9B Give to. by this,
High-frequency plasma is generated inside the vacuum chamber 1 of the laser introduction window 5, and dirt on the laser introduction window 5 is removed by plasma etching. The plasma source gas is preferably a gas that does not remain on the inner wall of the vacuum chamber 1 and does not corrode the inner wall, for example, oxygen or argon. According to the laser annealing apparatus 100 described above, even if the vaporized substance generated from the object to be processed M rises substantially vertically upward at the time of annealing and adheres to the vertically upper part of the laser irradiation part P, the high-frequency plasma By the generation mechanism,
It can be removed without opening the vacuum chamber 1. Therefore, the laser light R introduced from the laser introduction window 5
Energy can be prevented from decreasing due to contamination of the laser introduction window 5, and a decrease in processing efficiency can be prevented. Further, the reflected laser light reflected by the object to be processed M is not re-reflected by the contamination of the laser introduction window 5 and re-irradiated to the object to be processed M, so that the annealing can be favorably performed. Further, it is not necessary to open the vacuum chamber 1 and frequently clean the laser introduction window 5, so that the throughput can be improved and the production cost can be reduced. FIG. 2 shows the laser annealing apparatus 1 described above.
00 is a modified example of FIG. The ceiling 1a of the vacuum chamber 1 so that a closed space can be formed below the laser introduction window 5.
A laser introduction window 5 is provided via a spacer 14 and a gate valve 15 is provided. Then, the high-frequency electrode 9B is provided in the closed space, and the gas supply pipe 12 for the plasma source gas 13 and the exhaust pipe 12b are connected.
With this configuration, during the annealing process, the gate valve 1
5. Open and process. On the other hand, during the plasma cleaning process, the gate valve 15 is closed and the plasma source gas 1 is closed.
3 is supplied from the gas supply pipe 12 and sucked out from the exhaust pipe 12b, the vaporized material re-vaporized (floating) by the plasma source gas 13 and the plasma etching is not diffused into the entire vacuum chamber 1 and the efficiency is improved. Can be improved. [0015] The laser annealing apparatus (1) of the present invention
00), the conventional laser annealing apparatus (5
The contamination of the laser introduction window (5), which has been a problem in (00), can be removed without disassembling the apparatus. Therefore, maintenance for and time with a decrease can be prevented in the processing efficiency can be remarkably reduced, Ru can be improved productivity.

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 cross-sectional view of a main part of a modification of the laser annealing apparatus according to the first embodiment of the present invention. FIG. 3 is a main part of an example of a conventional laser annealing apparatus.
It is sectional drawing. [Description of Signs ] 100,500 Laser Annealing Apparatus 1 Vacuum Chamber 1a Ceiling 1b Exhaust Port 2 Moving Mount 5 Laser Introducing Window 6 Excimer Laser Irradiating Apparatus 9A, 9B High Frequency Electrode 10 High Frequency Generator 12 Gas Supply Pipe 13 Plasma Source gas B Base M Workpiece M1 Amorphous semiconductor thin film M2 Insulating substrate P Laser irradiated part R Laser light

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-221027 (JP, A) JP-A-6-122597 (JP, A) JP-A-7-122525 (JP, A) JP-A-7-122 211666 (JP, A) JP-A-9-102468 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00 B01J 19/12 H01L 21/268

Claims (1)

(57) [Claims 1] A laser for irradiating an object (M) placed in a closed container (1) with a laser beam (R) from outside through a laser introduction window (5). In the annealing treatment apparatus, by providing a high-frequency plasma generation mechanism near the laser introduction window (5), a vaporized substance generated from the object to be processed (M) and adhered to the laser introduction window (5) can be removed. A laser annealing apparatus (100) characterized in that: