JP2004087962A - Laser annealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To irradiate a substrate with a laser beam in a stable atmosphere of low oxygen concentration without upsizing the whole device and without making the device specific. <P>SOLUTION: The laser annealing device 1 is provided with optical systems 15 and 16 for irradiating a substrate 2 by guiding the laser beam emitted from a laser light source, and a cell 17 provided in an optical path between the optical systems 15 and 16 and the substrate 2. The cell 17 is cylindrical, the upper part thereof is sealed with glass or the like, and the lower part is opened. The cell 17 is arranged at a position neared sufficiently to the substrate 2. In this state, nitrogen gas is injected into an inside space of the cell 17 to perform laser annealing. <P>COPYRIGHT: (C)2004,JPO

Description

【００５０】
【発明の効果】
本発明にかかるレーザアニール装置では、筒状のガス保留部の開口部分を基板に近接して配置し、その筒内に例えば窒素等の不活性なガスを注入しながら、レーザ光を筒内を通過させて基板上に照射して、レーザアニールを行う。このようなレーザアニール装置では、基板とガス保留部との間の開口部の隙間から流出されるガスの流出量と、上記筒内に注入されるガスの注入量との関係を制御することによって、注入した不活性のガスの濃度を制御することができる。
【００５１】
このため、本発明にかかるレーザアニール装置では、基板上のレーザ光が照射されている部分が、窒素等の不活性ガスの雰囲気となる。すなわち、レーザ光が照射されている基板上の雰囲気の酸素濃度を低くすることができる。さらに、このレーザアニール装置では、筒状のガス保留部内部にのみ不活性ガスを注入すればよいので、局所的な小さな領域のみガスを注入すればよい。従って、例えばステージを含めた基板全体をチャンバ等で覆う従来のレーザアニール装置と比べて、装置全体を大型化及び特殊装置とすることなく、安定した低酸素濃度の雰囲気中で基板に対してレーザ光を照射することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態のレーザアニール装置の構成図である。
【図２】上記レーザアニール装置に設けられたセルの斜視図である。
【図３】上記セルの断面図である。
【図４】ｆθレンズ、セル、基板及びステージの断面図である。
【図５】レーザスポットの移動軌跡を示す図である。
【図６】直方体形状のセルの斜視図である。
【図７】残留酸素濃度の測定を行ったセルを示す図である。
【図８】残留酸素濃度の測定点を示す図である。
【符号の説明】
１　レーザアニール装置、１１　ステージ、１２　レーザ光源、１３　レーザ光合成光学系、１４　ビーム成形光学系、１５　レーザ光偏向部、１６　ｆθレンズ、１７　セル、１８　ガス供給部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laser annealing apparatus used for forming, for example, a polysilicon film serving as a channel layer of a thin film transistor.
[0002]
[Prior art]
In recent years, a thin film transistor using a polysilicon film for a channel layer has been widely used as a switching element of a liquid crystal display or the like. A polysilicon film used for a channel layer of a thin film transistor is generally manufactured using a process called low-temperature polysilicon. The low-temperature polysilicon process is a process for producing a polysilicon film by forming an amorphous silicon film on a glass substrate and irradiating the amorphous silicon with a laser beam to perform a heat treatment. In such a low-temperature polysilicon process, since heat is not transmitted to the glass substrate during annealing, an inexpensive glass substrate with low heat resistance can be used as the substrate of the liquid crystal display.
[0003]
[Problems to be solved by the invention]
In the low-temperature polysilicon process, an amorphous silicon film is heated, melted, and recrystallized using a laser annealing apparatus to produce a polysilicon film. However, if oxygen is contained in the annealing atmosphere, silicon Is oxidized, and the carrier mobility of the manufactured polysilicon is reduced. For this reason, the laser annealing apparatus used in the low-temperature polysilicon process must be configured so that the stage on which the glass substrate is mounted is covered with the chamber and the oxygen concentration in the chamber is reduced to perform the annealing. In order to lower the oxygen concentration in the chamber, for example, the inside of the chamber is evacuated to a vacuum after inserting the glass substrate, and the inside of the chamber is evacuated to a vacuum after the insertion of the glass substrate, and then nitrogen gas is injected. Alternatively, a preparatory chamber capable of vacuum degassing and having a load lock mechanism is provided outside the chamber, and the glass substrate is inserted from the preparatory chamber into the chamber.
[0004]
However, if the laser annealing apparatus is configured to be compatible with vacuum, the weight of the entire apparatus increases, and all the components in the chamber must be special equipment compatible with vacuum, resulting in a very high cost. .
[0005]
A technique for solving some of these problems is disclosed in Japanese Patent Application Laid-Open No. 9-8316. In this publication, the entire stage is covered with a chamber, the atmosphere on the substrate is controlled by continuously injecting nitrogen gas into the chamber, and further, the nitrogen gas is flown to the laser light irradiation part to the annealing part. There is shown a laser annealing apparatus which controls so that foreign matter does not adhere. In this laser annealing apparatus, the cost is reduced because the inside of the chamber does not need to be evacuated.
[0006]
However, even in the laser annealing apparatus disclosed in this publication, in order to improve the processing speed, a preparatory chamber capable of vacuum degassing and having a load lock mechanism is provided outside the chamber, and the glass substrate is moved from the preparatory chamber to the chamber. Need to be inserted into Further, in this laser annealing apparatus, the flow of the nitrogen gas becomes unstable due to the flow of the nitrogen gas, and the manufacturing characteristics vary.
[0007]
The present invention has been proposed in view of such conventional circumstances, and irradiates a substrate with laser light in an atmosphere having a stable low oxygen concentration without increasing the size of the entire apparatus and making it a special apparatus. It is an object of the present invention to provide a laser annealing apparatus capable of performing the above.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, a laser annealing apparatus according to the present invention is a laser annealing apparatus that irradiates a substrate with laser light and performs an annealing process on the substrate. A light emitting unit, a stage for holding the substrate, an optical system for guiding the laser light emitted from the laser light emitting unit and irradiating the substrate with the laser light, a cylindrical gas storage unit, and a gas storage unit. And a local atmosphere forming means having a gas injection port for injecting a gas from the outside.The local atmosphere forming means is provided at a position where one opening of the cylindrical gas retaining portion faces the stage. The optical path of the laser beam from the optical system to the substrate is disposed at a position passing from one opening to the other opening of the gas retaining portion having a cylindrical shape. Wherein the inert gas from the gas inlet is injected from the outside into the process.
[0009]
In the laser annealing apparatus as described above, the opening of the cylindrical gas retaining part is arranged close to the substrate. The laser annealing apparatus performs laser annealing by irradiating a substrate with laser light while passing an inert gas such as nitrogen into the cylinder while irradiating the substrate with the laser light. In such a laser annealing apparatus, the injected amount of gas is determined based on the relationship between the amount of gas flowing out from the gap between the substrate and the gas retaining portion and the amount of gas injected into the cylinder. The concentration of the active gas can be controlled.
[0010]
Further, in the laser annealing apparatus according to the present invention, for example, the cylindrical gas retaining portion has one opening not facing the stage sealed by an optical member of a laser beam output portion of the optical system. I have.
[0011]
In addition, in the laser annealing apparatus according to the present invention, for example, the cylindrical gas retaining section has one opening not facing the stage sealed with a transparent member, and the optical gas through the transparent member. It is arranged at a position where laser light is incident from the system.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, as an embodiment of the present invention, a laser annealing apparatus to which the present invention is applied will be described in detail with reference to the drawings.
[0013]
A laser annealing apparatus according to an embodiment of the present invention is an apparatus that irradiates a surface of a flat substrate to be annealed with a laser beam and heat-treats the substrate with the irradiated laser beam. The laser annealing apparatus according to the embodiment of the present invention is used, for example, when forming a channel layer of a thin film transistor serving as a switching element of a liquid crystal display device or an organic EL display device. Specifically, it is used when an amorphous silicon film formed on a glass substrate is heat-treated to form a polysilicon film.
[0014]
FIG. 1 shows a configuration diagram of a laser annealing apparatus 1 according to an embodiment of the present invention.
[0015]
The laser annealing apparatus 1 includes a stage 11 on which a flat substrate 2 to be annealed is placed, first to fourth laser light sources 12 (12-1 to 12-4) for emitting laser light, A beam combining optical system 13 to which each output light of the laser light source 12 is incident, a beam shaping optical system 14 to which the output light of the beam combining optical system 13 is incident, and a laser beam output from the beam shaping optical system 14 are emitted. A laser beam deflecting unit 15 for irradiating the substrate 2 while deflecting the direction, an fθ lens 16 provided in an optical path between the laser beam deflecting unit 15 and the stage 2, an fθ lens 16 and the stage 2 And a gas supply unit 18 for supplying nitrogen (N ₂ ) gas into the cell 17.
[0016]
The stage 11 has a flat main surface 11a on which the flat substrate 2 is mounted. The stage 11 moves in a direction parallel to the main surface 11a (the X and Y directions in FIG. 1) while holding the substrate 2 placed on the main surface 11a. By moving the stage 11, the relative position between the substrate 2 and the irradiation spot of the laser beam can be moved. That is, by moving the stage 11, the position on the substrate 2 where the annealing is performed can be controlled. The movement of the stage 11 is controlled by a controller (not shown).
[0017]
The first to fourth laser light sources 12 (12-1 to 12-4) are laser light sources that emit laser light having a wavelength in a region where the absorption coefficient of silicon is high, such as a laser light in an ultraviolet region. For example, the laser light source 12 is a pulse laser light source of the third harmonic (355 nm) of the YAG laser. Further, a laser oscillation source for outputting a second harmonic, a third harmonic, a fourth harmonic, or the like such as a Nd: YAG laser, a Nd: YLF laser, a Nd: glass fiber laser, an Nd: YV04 laser, and a Yb: YAG laser. Or a semiconductor laser using a composition in which GaN or Ga is partially replaced with Al or In for the active layer. Although the laser annealing apparatus 1 of the present embodiment includes four laser light sources 12 (12-1 to 12-4), the number is not limited to four and may be any number.
[0018]
The beam combining optical system 13 receives four laser beams emitted from the first to fourth laser light sources 12 (12-1 to 12-4). The beam combining optical system 13 superimposes these laser beams with a beam splitter or a mirror, combines the laser beams into a single-beam laser beam, and outputs the combined laser beam.
[0019]
The beam shaping optical system 14 receives one laser beam emitted from the beam combining optical system 13. The beam shaping optical system 14 averages the energy density of a cross section perpendicular to the optical axis of the incident laser light, and shapes the beam diameter into, for example, a rectangular shape.
[0020]
The laser light deflecting unit 15 is an optical member that deflects the incident laser light and guides the light on the substrate 2. For example, the laser deflection unit 15 is a galvanometer having a galvanometer 19 and a reflecting mirror 20 connected to the galvanometer 19. The laser beam deflecting unit 15 receives the laser beam emitted from the beam shaping optical system 14, reflects the incident laser beam by the reflecting mirror 20, and irradiates the substrate 2 on the stage 11. The galvanometer 19 rotationally moves the reflecting mirror 20 so as to reciprocate within a range of a fixed rotation angle. By moving the reflecting mirror 20 by the galvanometer 19 in this manner, the laser irradiation position on the substrate 2 reciprocates within a predetermined range. Here, it is assumed that the laser light deflecting unit 15 is arranged such that the irradiation position of the laser light linearly moves in the Y direction in the drawing by the movement of the reflecting mirror 20 by the galvanometer 19.
[0021]
lens 16 is provided on the optical path of the laser light between the laser light deflecting unit 15 and the substrate 2. When the irradiation position of the laser light is controlled using an optical member such as a galvano scanner, the length of the optical path up to the substrate 2 and the incident angle of the laser light on the substrate 2 vary depending on the irradiation position of the laser light. Therefore, distortion occurs in the energy density distribution and the spot shape of the laser spot irradiated on the substrate 2. fθ lens 16 is a lens that corrects a distortion of a laser spot on the substrate 2 caused by moving the irradiation position of the laser light by the laser light deflecting unit 15.
[0022]
As shown in FIG. 2, the cell 17 includes a cylindrical gas storage part 21, a window 22 made of a transparent member provided at one opening of the gas storage part 21, and a side part of the gas storage part 21. And two gas injection nozzles 23 (23a, 23b).
[0023]
The gas retaining part 21 has a cylindrical shape. The gas retaining part 21 is closed at one opening of the cylinder by a window 22 made of a transparent member. The other opening of the cylinder remains open. The opening where the window 22 is not provided is referred to as an opening 24.
[0024]
The window 22 is, for example, glass or the like, but may be made of any material as long as it transmits laser light having a wavelength emitted from the laser light source 12.
[0025]
The gas injection nozzle 23 (23a, 23b) has a straight pipe shape in which an insertion hole 25 having a diameter sufficiently smaller than the diameter of the cylinder of the gas storage part 21 is formed. One end of the gas injection nozzle 23 is connected to the gas storage unit 21. The other end of the gas injection nozzle 23 that is not connected to the gas storage unit 21 is connected to the gas supply unit 18 via a soft tube or the like. At the time of laser annealing, the gas injection nozzle 23 is injected with a nitrogen gas at a predetermined flow rate from the end that is not connected to the gas storage unit 21.
[0026]
The gas injection nozzle 23 is connected to an end of the side surface of the gas storage unit 21 on the side of the window 22. The insertion hole 25 of the gas injection nozzle 23 is connected to the internal space of the cylindrical gas storage unit 21. Therefore, when nitrogen gas is injected from the gas supply unit 18 to the gas injection nozzle 23, the nitrogen gas is injected into the internal space of the gas storage unit 21. As shown in FIG. 3, the gas injection nozzle 23 is configured such that the central axis of the cylindrical gas storage part 21 and the direction in which the insertion hole 25 is formed are perpendicular to each other, and the gas storage nozzle 21 It is arranged so that the tangential direction of the inner periphery of the portion 21 and the direction in which the insertion hole 25 is formed are parallel. That is, the gas injection nozzle 23 is arranged so that when nitrogen gas is injected, the nitrogen gas is injected along the side wall of the internal space of the gas storage unit 21.
[0027]
When nitrogen gas is injected into the internal space at a predetermined flow rate from the gas injection nozzle 23, the cell 17 having such a configuration fills the internal space while generating convection in which the nitrogen gas rotates along the side wall, and the opening 17 It is discharged to the outside from 24. Therefore, when nitrogen gas is injected from the gas injection nozzle 23 in the cell 17, turbulence does not easily occur in the internal space, and external gas is not sucked from the opening 24. That is, when nitrogen gas is injected from the gas injection nozzle 23, the cell 17 has a nitrogen atmosphere in which the internal space has a low oxygen density.
[0028]
The cell 17 is disposed between the fθ lens 16 and the substrate 2 as shown in FIG. 4, and has a central axis of the cylindrical gas storage unit 21 and a central axis of a laser beam deflection range (in FIG. 4). (The line indicated by L). The center axis of the laser light deflection range is the optical axis of the laser light in the reference state where the galvanometer 19 is not driven. In the direction of arrangement of the cells 17, the window 22 is on the fθ lens 16 side, and the opening 24 is on the stage 11 side.
[0029]
Here, the cell 17 is arranged at a position sufficiently close to the flat substrate 2. When the cell 17 is arranged at a position sufficiently close to the substrate 2, the substrate 2 acts as a barrier, and the nitrogen gas filling the inside of the cell 17 is discharged in a direction parallel to the substrate 2. The gas outside the cell 17 does not flow into the space (space D) between the cell 17 and the substrate 2. Therefore, the space D between the cell 17 and the substrate 2 is also filled with the nitrogen gas, and becomes a nitrogen atmosphere. In particular, since the internal space of the cell 17 generates rotational convection around the optical axis L of the nitrogen gas, the nitrogen gas is uniformly discharged from the entire circumferential portion of the opening 24, and turbulence occurs. It becomes difficult and external gas does not flow.
[0030]
The radius of the cylindrical gas storage unit 21 is set to be sufficiently large so that the optical path of the laser light deflected by the laser light deflection unit 15 is not blocked by the side surface of the cylindrical gas storage unit 21. . That is, even if the laser beam irradiated on the substrate 2 is deflected by the laser beam deflecting unit 15, the laser beam is incident from the window 22 into the internal space of the cell 17, and is not refracted or reflected from the opening 24. Output to
[0031]
The operation of the laser annealing apparatus 1 configured as described above will be described.
[0032]
When the substrate 2 is mounted on the stage 11, the laser annealing apparatus 1 emits laser light from each laser light source 12, and operates the stage 11 and the laser light deflecting unit 15 to start an annealing process on the substrate 2.
[0033]
The operations of the stage 11 and the laser beam deflecting unit 15 are as follows.
[0034]
FIG. 5 is a schematic view showing the surface of the substrate 2 during laser annealing. The laser annealing apparatus 1 operates the laser beam deflecting unit 15 to linearly move the irradiation spot L of the laser beam on the substrate 2 repeatedly within a certain range. Here, it is assumed that the irradiation spot L reciprocates in the Y direction in FIG. 5 within a range of Y1. Further, the laser annealing apparatus 1 moves the stage 11 in the X direction so that the position of the irradiation spot L moves from one end in the X direction on the substrate 2 to the other end at a constant speed. The X direction is a direction orthogonal to the Y direction.
[0035]
When the stage 11 and the laser beam deflecting unit 15 are operated together in this way, the irradiation spot L on the substrate 2 moves along a sine-wave locus in the X direction as shown in FIG.
[0036]
Then, when the movement in the X direction is completed, the laser annealing apparatus 1 temporarily stops emitting the laser light, moves the stage 11 by the distance Y1 in the Y direction, and repeats the same operation. Therefore, in the laser annealing apparatus 1, by adjusting the moving speed of the stage 11 and the reciprocating movement speed of the galvano according to the size of the irradiation spot, it is possible to irradiate the laser beam over the entire range of the substrate 2. . That is, annealing can be performed on the entire surface of the substrate 2.
[0037]
Further, the laser annealing apparatus 1 injects nitrogen gas from the gas supply unit 18 into the cell 17 at a predetermined flow rate during the above-described laser annealing process.
[0038]
When nitrogen gas is injected into the cell 17, the internal space of the cell 17 becomes a nitrogen atmosphere, and the space D between the cell 17 and the substrate 2 also becomes a nitrogen atmosphere. That is, the atmosphere around the laser light irradiation position is a nitrogen atmosphere.
[0039]
When the surrounding atmosphere of the laser beam irradiation position becomes a nitrogen atmosphere in this way, the oxygen concentration in the surrounding atmosphere is reduced regardless of the outside atmosphere of the cell 17, and the oxidation of the substrate 2 is suppressed. That is, even if the outside atmosphere of the cell 17 is air, the oxidation of the substrate 2 can be suppressed. Therefore, in the laser annealing apparatus 1 according to the embodiment of the present invention, it is not necessary to surround the entire stage 11 with a chamber or the like to perform vacuum degassing or the like, for example, in order to prevent oxidation of the substrate 2 during laser annealing.
[0040]
As described above, in the laser annealing apparatus 1 according to the embodiment of the present invention, it is possible to irradiate the substrate with laser light in an atmosphere having a stable low oxygen concentration without increasing the size of the entire apparatus and using a special apparatus. it can. Therefore, the size and cost of the device can be reduced.
[0041]
Furthermore, in the laser annealing apparatus 1 according to the embodiment of the present invention, since only the atmosphere in the cell 17 needs to be adjusted, the time required for adjusting the atmosphere is very short, and the throughput of the process is improved. I can do it.
[0042]
In the laser annealing apparatus 1 according to the present embodiment, the cell 17 is provided with the window 22 which is a transparent member to seal one end of the cylindrical gas retaining portion 21. May be controlled so that the space between the cell 17 and the substrate 2 can be made into a nitrogen atmosphere, and the window 22 may be left open without being provided.
[0043]
In addition, for example, a configuration may be adopted in which the lens barrel of the fθ lens 16 is directly connected without providing the window 22 to seal nitrogen gas.
[0044]
Further, in the laser annealing apparatus 1 of the present embodiment, the cell 17 has a cylindrical shape. However, as long as at least the cell 17 has a cylindrical shape, the shape is not limited to a cylinder and may be any shape. For example, when an excimer laser or the like is used for the laser light source 12, or when a polygon mirror or the like is used for the laser beam deflecting unit 15, the irradiation spot shape of the laser beam irradiated on the substrate 2 becomes a linear shape having a high aspect ratio. It becomes a beam. In such a case, when the cell 17 is formed in a rectangular parallelepiped shape closer to the beam shape as shown in FIG. 6, for example, the volume of the internal space becomes smaller and the control of the atmosphere becomes easier.
[0045]
Further, in the laser annealing apparatus 1 of the present embodiment, a nitrogen gas is used as a gas to be injected into the internal space of the cell 17, but for example, it is hard to react with other elements in a normal state, and is a so-called inert gas. If so, other than nitrogen gas may be used.
[0046]
Experimental example The present inventor used the cell 17 having the cylindrical shape and the gas 17 having two gas injection nozzles 23 under the condition shown in FIG. The residual oxygen concentration in the space between was measured. The atmosphere outside the cell 17 is air.
[0047]
Inner diameter (φ1) of cylinder of gas storage unit 21: 34 mm
Outer diameter (φ2) of cylinder of gas storage unit 21: 38 mm
Wall thickness (t) of the side wall of the gas retaining part 21 and the window 22: 2 mm
Height (h1) of the internal space of the cylinder of the gas storage unit 21: 29 mm
Inner diameter (φ3) of insertion hole 25 of gas injection nozzle 23: 4 mm
Height (h2) from opening 24 to center of insertion hole 25: 25.5 mm
Distance (g) between cell 17 and substrate 2: 1.1 mm
The residual oxygen concentration was measured by a gas sensor inserted from above the cell 17 (window 22 side) as shown in FIG. The measurement position by the gas sensor was the center position of the cylinder, and was the space D between the cell 17 and the substrate 2.
[0048]
As a result of measuring the residual oxygen concentration under the above conditions, the residual oxygen concentration was as follows.
[0049]
[Table 1]

[0050]
【The invention's effect】
In the laser annealing apparatus according to the present invention, the opening portion of the cylindrical gas retaining portion is arranged close to the substrate, and the laser beam is passed through the cylinder while injecting an inert gas such as nitrogen into the cylinder. Irradiation is performed on the substrate by passing through, and laser annealing is performed. In such a laser annealing apparatus, by controlling the relationship between the outflow amount of the gas flowing out of the gap between the opening portion between the substrate and the gas retaining portion and the injection amount of the gas injected into the cylinder, In addition, the concentration of the injected inert gas can be controlled.
[0051]
For this reason, in the laser annealing apparatus according to the present invention, the portion of the substrate irradiated with the laser light becomes an atmosphere of an inert gas such as nitrogen. That is, the oxygen concentration in the atmosphere on the substrate to which the laser light is irradiated can be reduced. Furthermore, in this laser annealing apparatus, since the inert gas only needs to be injected into the cylindrical gas retaining portion, the gas may be injected only into a small local area. Therefore, compared with a conventional laser annealing apparatus that covers the entire substrate including the stage with a chamber, for example, the laser is applied to the substrate in an atmosphere with a stable low oxygen concentration without increasing the size of the entire apparatus and using a special apparatus. Light can be applied.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a laser annealing apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of a cell provided in the laser annealing apparatus.
FIG. 3 is a sectional view of the cell.
FIG. 4 is a sectional view of an fθ lens, a cell, a substrate, and a stage.
FIG. 5 is a diagram showing a movement locus of a laser spot.
FIG. 6 is a perspective view of a rectangular parallelepiped cell.
FIG. 7 is a diagram showing a cell in which the measurement of the residual oxygen concentration is performed.
FIG. 8 is a diagram showing measurement points of the residual oxygen concentration.
[Explanation of symbols]
Reference Signs List 1 laser annealing device, 11 stage, 12 laser light source, 13 laser light synthesis optical system, 14 beam shaping optical system, 15 laser light deflection unit, 16 fθ lens, 17 cell, 18 gas supply unit

Claims (6)

In a laser annealing apparatus that irradiates a substrate with laser light to perform an annealing process on the substrate,
Laser light emitting means for emitting laser light,
A stage for holding the substrate,
An optical system that guides the laser light emitted from the laser light emitting means and irradiates the substrate with the light
A local gas forming unit having a cylindrical gas storage unit and a gas injection port for injecting gas from outside into the gas storage unit,
The local atmosphere forming means is arranged such that one opening of the cylindrical gas storage section is located at a position facing the stage, and the optical path of the laser light from the optical system to the substrate is the cylindrical gas storage section. A laser annealing apparatus which is arranged at a position passing from one opening to another opening of the portion, and wherein an inert gas is externally injected from the gas injection port during laser annealing. The cylindrical gas retaining portion has one opening not facing the stage sealed with a transparent member, and is disposed at a position where laser light is incident from the optical system via the transparent member. 2. The laser annealing apparatus according to claim 1, wherein 2. A laser annealing apparatus according to claim 1, wherein said cylindrical gas retaining portion has one opening not facing said stage sealed by an optical member of a laser beam output portion of said optical system. apparatus. 2. The laser annealing apparatus according to claim 1, wherein the gas retaining section has a cylindrical shape. The gas storage unit, one opening portion not facing the stage is sealed by an optical member or a transparent member of the laser beam output portion of the optical system,
The gas inlet is provided at an end of the side wall of the gas storage unit on one side of the opening that is not opposed to the stage, and supplies an inert gas along a tangential direction of an inner wall of the gas storage unit. 5. The laser annealing apparatus according to claim 4, wherein the laser annealing is performed. 2. The laser annealing apparatus according to claim 1, wherein the inert gas is a nitrogen gas.

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