JP3505395B2 - Laser annealing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laser annealing apparatus for forming a good semiconductor film on a substrate.

[0002]

2. Description of the Related Art In recent years, in a semiconductor device manufacturing process, a semiconductor film on a substrate is subjected to laser annealing to promote activation or to crystallize an amorphous film. Above all, when a liquid crystal display (LCD) is manufactured using a substrate having a low heat resistance limit temperature,
Polysilicon (p-) obtained by crystallizing amorphous silicon (a-Si) on the substrate by laser annealing.
If Si) is used, not only as a switching element in the display pixel section but also a peripheral driver section for driving the display pixel section can be integrally formed on the same substrate. The laser annealing technology is an essential element for mass production of such driver-incorporated LCDs.

FIG. 2 shows the structure of such a laser annealing apparatus. (51) is a laser oscillation source including a laser medium and a resonance system, and (52) is a light shield (5
An optical system in which a lens (55), a mirror (56) and the like are installed in 7), and (53) is a final irradiation part of a laser beam,
(54) is a chamber in which laser annealing is performed,
Reference numeral (58) is a mounting table for supporting the target substrate (59) on which a-Si to be laser annealed is formed.

The laser light generated by the laser oscillation source (51) is shaped by the optical system (52) into the shape of a predetermined irradiation area, and is irradiated from the irradiation unit (53) into the chamber (54). It The chamber (54) is maintained at a predetermined pressure and temperature that are optimal for the laser annealing process. Chamber (5
In the inside of 4), the support base (5) on which the substrate (59) to be processed is placed
8) is scanned in such a manner that it moves in a certain direction and passes through the laser irradiation region, and laser annealing is performed on the entire surface.

[0005]

When a-Si (59) is crystallized in the laser annealing process, various other physicochemical reactions are accompanied with the crystallization of a-Si (59). The characteristics of the element using the p-Si film change. Therefore, it is preferable to remove the element that easily causes the physicochemical reaction by setting the vacuum atmosphere in the chamber (54). However, if the chamber (54) that can withstand such a vacuum state and the exhaust / air supply equipment are provided, the apparatus becomes expensive. Further, it takes a long time to evacuate the substrate (59) to be processed.

An object of the present invention is to perform laser annealing at
An object of the present invention is to provide an apparatus capable of preventing an unnecessary physicochemical reaction and enabling laser annealing while suppressing the manufacturing cost.

[0007]

The present invention achieves this object, and comprises a laser oscillation source for generating a laser beam and a laser beam emitted from the laser oscillation source, which is composed of a plurality of optical components. In a laser annealing apparatus having an optical system and a processing chamber provided with a mounting table for supporting an object to be laser-annealed at a position to be irradiated with a laser beam sent from the optical system, the processing chamber comprises:
This is a configuration including an introduction pipe for introducing an inert gas into the interior, and a gas diffusion means for diffusing the inert gas.

As a result, the inside of the processing chamber is replaced with the inert gas, so that it is possible to prevent physicochemical reactions other than laser annealing. Further, since it is not necessary to evacuate the processing chamber, increase in manufacturing cost can be avoided.

[0009]

1 is a block diagram of a laser annealing apparatus according to an embodiment of the present invention. (11) is a laser oscillation source including a laser medium and a resonance system,
2) is a lens (15) in the light shield (17),
An optical system provided with a mirror (16) and the like, (13) a final irradiation part of a laser beam, (14) a chamber where laser annealing is performed, and (18) formed a-Si to be laser annealed. This is a mounting table for supporting the substrate (19) to be processed.

The chamber (14) is an airtight chamber, and has an air supply system including an air supply valve (1), an air supply pump (2) and an air supply pipe (3) communicating therewith, and an exhaust valve (5) and an exhaust pump. It is equipped with an exhaust system consisting of (6) and an exhaust pipe (7). (5) is a shower head-shaped diffusion filter according to the present invention, which is attached to the outlet (4) of the air supply pipe (3) introduced into the chamber (14).

With this configuration, during the laser annealing process,
The air supply valve (1) and the exhaust valve (5) are opened, and, for example, nitrogen as an inert gas is introduced into the chamber (14) and discharged from the exhaust system. At this time, the inside of the chamber (14) is kept at an atmospheric pressure almost equal to the atmospheric pressure. That is, during the laser annealing process, the chamber (14) is constantly replaced by the nitrogen flow. For this reason, the laser annealing process is always performed in an inert nitrogen atmosphere, so that a physicochemical reaction does not occur due to laser energy. Further, even if a reactive substance activated by the laser annealing process is generated, it is removed by the nitrogen flow.

Particularly, in the present invention, due to the diffusion filter (5) provided at the outlet (4), the supplied nitrogen gas flow is diffused and introduced into the chamber (14). This is for the following reason. If,
When the flow of nitrogen is vigorously introduced into the chamber (14), variations in nitrogen density occur in the chamber (14),
The effect of removing the reactive substance by the nitrogen flow is
9) It depends on the position above. For this reason, the characteristics of the element using the p-Si film obtained by laser annealing vary on the substrate, which adversely affects the operation of the entire device including such an element. Therefore, in the present invention, by providing the diffusion filter (5) at the outlet (4), the nitrogen flow introduced into the chamber (14) is diffused and the nitrogen flow is made uniform, so that the reactivity is improved. To make the substance removal effect uniform on the substrate (19) to be processed,
Stabilization of the characteristics of the obtained device is achieved.

[0013]

As is apparent from the above description, the laser annealing apparatus of the present invention realizes laser annealing in which the laser annealing atmosphere is improved and uniform characteristics are obtained without increasing the apparatus cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser annealing apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional laser annealing apparatus.

[Explanation of symbols]

1 Air supply valve 2 Air supply pump 3 air supply pipe 4 outlet 5 Diffusion filter 11 Laser oscillation source 12 Optical system 13 Irradiation part 14 chambers 15 lenses 16 mirror 17 Light shield 18 table 19 substrate to be processed 20 windows

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-9-8316 (JP, A) JP-A 10-172911 (JP, A) JP-A 10-74753 (JP, A) JP-A 61- 129834 (JP, A) JP 9-102467 (JP, A) JP 6-17120 (JP, A) JP 10-149984 (JP, A) JP 55-12748 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/26-21/268 H01L 21/322-21/326 H01L 21/20

Claims (3)

(57) [Claims] 1. A laser source for generating a laser beam, an optical system composed of a plurality of optical components for shaping the laser beam emitted from the laser source, and a laser beam emitted from the optical system to be irradiated. In a laser annealing apparatus having a processing chamber provided with a mounting table for indicating an object to be laser-annealed at a position, the processing chamber has an air supply means for introducing an inert gas therein, and the introduced gas. Uniform inert gas in the processing chamber
Spread, comprising a diffusion means so that variation does not occur that the laser annealing apparatus according to claim. 2. The laser annealing apparatus according to claim 1, wherein the inert gas contains nitrogen as a main component. 3. The laser annealing apparatus according to claim 1, wherein the diffusing unit is a diffusing filter formed in a shower head shape.