JPH09186085A - Laser annealing method and laser annealing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film adapted to a device such as a thin film transistor by improving the crystallinity, homogeneity in the film surface of a crystal and utilizing efficiency of laser energy in the case of laser annealing a non-single crystal silicon film. SOLUTION: A laser beam is directed to a non-single crystal silicon film 202 in an atmosphere containing oxygen, and laser annealed. Particularly, the upper surface of the film 201 is oxidized to form a silicon oxide film 204 having a thickness of 100Å or less, and laser annealed in this state. Before the upper surface of the film 202 is oxidized, the cleaning step of removing a natural oxide film and impurities is conducted. Thus, the film 104 after the annealing can be made to be suitable for a device such as a thin film transistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous silicon film or a crystalline silicon film formed on an insulating substrate such as glass which is crystallized by laser annealing. On how to improve.

[0002]

2. Description of the Related Art In recent years, an amorphous silicon film or a crystalline silicon film (a silicon film having crystallinity such as polycrystal or microcrystal, which is not single crystal) formed on an insulating substrate such as glass, that is, A technique of subjecting a single crystal silicon film to laser annealing to crystallize or improve the crystallinity has been widely studied.

Since a crystalline silicon film formed by laser annealing has a high mobility, a thin film transistor (TFT) is formed using this crystalline silicon film, and for example, a pixel is formed on one glass substrate. It is widely used in monolithic type liquid crystal electro-optical devices for manufacturing driving and driving circuit TFTs.

Further, a pulsed laser beam such as an excimer laser, which has a large output, is irradiated on the surface to be irradiated by several cm.
It is processed by an optical system so that it becomes a square spot with a square or a linear shape of several millimeters width x several tens of centimeters, and scans with a laser beam (by moving the laser beam irradiation position relative to the irradiated surface ), A method of performing laser annealing is preferably used because it has good mass productivity and is industrially excellent.

In particular, when a linear laser beam is used, unlike the case of using a spot-shaped laser beam which requires front, rear, left and right scanning, laser irradiation is performed on the entire surface to be irradiated by scanning only in a direction perpendicular to the line direction. Because you can do
High mass productivity is obtained.

[0006]

There are some problems in performing laser annealing on a non-single-crystal silicon film by scanning a spot-shaped or linear laser beam using a pulsed laser beam as a light source. Has occurred.

For example, when laser annealing is performed in air, carbon and other impurities contained in air are likely to be mixed in the film, and the film quality and crystallinity of the crystalline silicon film after annealing,
There are problems such as deterioration of various characteristics such as mobility.

Further, when laser irradiation is performed by scanning a laser beam having a spot-like or linear shape on the surface to be irradiated in an atmosphere of an inert gas such as vacuum or nitrogen, it is compared with annealing in air. There are the following problems.

Poor crystallinity. That is, as compared with annealing in air, high crystallinity cannot be obtained unless the energy density of the laser is significantly increased.

The homogeneity of the crystal in the film plane is poor. Places with good and bad crystallinity are distributed in the film plane. For example, when the linear laser beam is scanned in a direction perpendicular to the line direction of the beam, a good crystallinity region and a bad crystallinity region appear in a stripe pattern in the film surface. Therefore, when a plurality of thin film transistors are manufactured using the manufactured crystalline silicon film, various characteristics such as threshold value and mobility are different depending on the positions of the thin film transistors on the substrate.

Energy use efficiency is poor. In order to improve the crystallinity, it is necessary to increase the energy density of the laser. Increasing the energy density also increases the power consumption, and in addition, the laser irradiation equipment including the laser oscillator, circuit, gas, and optical system is also exhausted. And increase the cost of the device to be manufactured. On the other hand, when the energy density of the laser increases, the crystallinity increases, but the entire film after laser annealing becomes extremely rough, and it becomes difficult to process the film to manufacture a device.

The present invention is to solve the above problems.

[0013]

In order to solve the above problems, one of the main structures disclosed in this specification is to perform a first step of cleaning a non-single-crystal silicon film formed on a substrate. A second step of laser annealing the non-single-crystal silicon film in an atmosphere containing oxygen, wherein the first step and the second step are continuously performed without being exposed to the atmosphere. The laser annealing method is characterized by being performed by

In the above structure, it is preferable that the second step is performed after the upper surface of the non-single crystal silicon film is oxidized in the atmosphere containing oxygen.

Further, one of the other structures is a first step of cleaning the non-single-crystal silicon film formed on the substrate, and the upper surface of the non-single-crystal silicon film is oxidized to form a silicon oxide film. Second
And a third step of laser annealing the non-single-crystal silicon film. At least the first step and the second step of the steps are continuously performed without being exposed to the atmosphere. The laser annealing method is characterized by being performed by

In the above structure, it is preferable that the third step is performed in a nitrogen atmosphere.

Further, one of the other structures has at least a cleaning chamber and a laser irradiation chamber, and the substrate to be processed is transported between the chambers without being exposed to the atmosphere. It is a device.

Further, one of the other structures has at least a cleaning chamber, a preheating chamber, and a laser irradiation chamber, and the substrate to be processed is not exposed to the atmosphere between the cleaning chamber and the preheating chamber. The laser annealing apparatus is characterized in that the laser annealing apparatus is transported to the.

In the present specification, the term "continuous" does not include a step between the first step and the second step in which impurities or other undesired substances are attached to the non-single crystal silicon film. means.

Therefore, for example, between the first step and the second step, the step of heating the substrate to a temperature required for the substrate transfer step, the alignment step, the slow cooling step, and the second step,
It can be said that having a dehydrogenation step by heating and the like is within the continuous range in the present specification.

On the other hand, the steps of exposing the non-single-crystal silicon film to a specific atmosphere for changing the film quality, the steps of ion doping, film formation, etching, plasma treatment, coating of the film are the first step and the second step. If there is an interval, it does not apply to the definition of continuity as used herein.

In the present invention, when laser annealing is applied to a non-single crystal silicon film to improve crystallization and crystallinity,
The upper surface of the non-single crystal silicon film is oxidized in an atmosphere containing oxygen to form a silicon oxide film having a film thickness of 100 Å or less, and then a laser beam is irradiated.

Further, the non-single crystal silicon film is irradiated with laser in a state of being arranged in an atmosphere containing oxygen.

Furthermore, a step of cleaning the non-single-crystal silicon film to remove a natural oxide film and impurities, a step of irradiating the non-single-crystal silicon film with a laser in an atmosphere containing oxygen, or an atmosphere containing oxygen. The step of forming a silicon oxide film on the upper surface of the non-single crystal silicon film is continuously performed without exposing to the atmosphere.

When the upper surface of the non-single crystal silicon film is oxidized to form a silicon oxide film having a film thickness of 100 Å or less and laser annealing is performed in this state, a crystalline silicon film which is more pure than laser annealing in air is obtained. Not only is it obtained, but also including air,
Compared to laser annealing in other atmospheres,
Excellent properties are produced in the following points. The crystallinity of the crystalline silicon film is improved. The crystallinity of the crystalline silicon film is made uniform in the film plane. The energy density of the laser required for crystallization decreases.

By providing this ultra-thin silicon oxide film, it is possible to suppress the reflection / emission of energy of the laser beam with which the non-single-crystal silicon film is irradiated and to keep the applied energy in the film. Conceivable. Therefore, more energy can be applied and crystallinity is improved than in the case where the silicon oxide film is not provided on the non-single-crystal silicon film.

At the same time, the unevenness and variation of the energy density of each pulse of the laser beam are homogenized, so that the crystallinity is also homogenized in the film plane.

Furthermore, since the reflection / emission of laser energy into the atmosphere is reduced and the energy is effectively used for crystallization, the energy density of the laser beam to be irradiated can be reduced.

When the energy density of the laser beam is set to a high value in the state where the silicon oxide film is provided on the non-single-crystal silicon film as in the case where the silicon oxide film is not provided, the energy loss is small and extra. However, the crystallinity is increased, but the entire film is greatly roughened. It is extremely difficult to manufacture a device such as a thin film transistor using such a film.

Before laser annealing, HF
It is preferable to remove the natural oxide film by washing the upper surface of the non-single crystal silicon film with an aqueous solution or an aqueous solution containing HF and H ₂ O ₂ . The subsequent silicon oxide film forming step or laser annealing step in an oxygen-containing atmosphere is preferably performed while heating the substrate, because the silicon oxide film forming rate is improved. It may be irradiated with ultraviolet rays.

In particular, this cleaning step and the subsequent laser annealing step in an oxygen atmosphere are continuously performed without exposing to the atmosphere, or the cleaning step and the heating in an oxygen atmosphere (oxide film silicon film formation) step. It is preferable to continuously perform the laser annealing step without exposing to the atmosphere.

By doing so, the extremely clean upper surface of the non-single-crystal silicon film can be used as the silicon oxide film. As a result, the film thickness and film quality of the formed silicon oxide film become more uniform, and the film quality uniformity in the substrate surface of the film crystallized by laser annealing is improved.

Further, the penetration of impurities into the non-single crystal silicon film during laser annealing is further reduced. As a result, various characteristics such as mobility and threshold value of a device such as a thin film transistor manufactured using the film can be more stable within the substrate surface and between lots.

The atmosphere containing oxygen is preferably oxygen alone or a mixed gas of oxygen and an inert gas such as nitrogen, helium or argon. It is desirable that the mixed gas contains oxygen at 1% or more, more preferably 5% or more under atmospheric pressure. When the oxygen content is less than 1%, the time required for forming a sufficient silicon oxide film becomes extremely long or is not formed, and the effect of the present invention cannot be sufficiently obtained, which is not practical. When the oxygen content is 5% or more, the effect of the present invention can be stably obtained.

When air is used as the oxygen-containing atmosphere for forming the silicon oxide film, impurities such as carbon in the air are mixed into the film to be annealed, and the mobility of the crystalline silicon film and other In many cases, various characteristics deteriorate or the characteristics of each lot become unstable. However, it is effective to perform laser annealing in an air atmosphere after forming the silicon oxide film in another atmosphere.

It is particularly preferable that the oxygen or inert gas constituting the oxygen-containing atmosphere has a purity of 99.9% (3N) or more and 99.99999% (7N) or less. By setting the atmosphere using a gas of such a purity, it is possible to prevent carbon, water, hydrocarbons, and other impurities from being mixed into the crystalline silicon film, and stabilize the film quality and film characteristics.
In addition, a crystalline silicon film having excellent characteristics can be obtained. When the purity of oxygen or an inert gas constituting the atmosphere is less than 3N, there is almost no difference from the case where an air atmosphere is used, and impurities tend to make the film characteristics unstable. Moreover, even if a high-purity material having a purity higher than 7N is used, the effect is not so different as compared with the case of 7N or less, and only the cost is increased.
Not preferred.

If the film thickness of the silicon oxide film is 100 Å or more, the amount of the silicon oxide film mixed in the crystalline silicon film increases due to the laser irradiation, and the crystallinity and mobility of the crystalline silicon film are increased. Various characteristics will deteriorate. On the other hand, if the film thickness is too thin, about 5 Å or less, the effects of the present invention described above are significantly reduced. The thickness of the silicon oxide film is 5 to
100 Å, preferably 10 to 50 Å, more preferably 20 to 40 Å are suitable.

The pressure during laser annealing may be atmospheric pressure. In addition, the pressure during laser annealing is below atmospheric pressure,
In particular, when the pressure is reduced to 0.01 Torr or more and 700 Torr or less, the pulsed laser is irradiated multiple times,
Roughness of the upper surface of the crystalline silicon film or the entire film is reduced, which is preferable. That is, the pulsed laser irradiation resistance of the crystalline silicon film is improved, and a film with less roughness can be obtained. If the pressure during laser annealing is higher than 700 Torr, the roughness of the film is almost the same as the atmospheric pressure. Pressure is 0.0
If it is less than 1 Torr, the effect of improving the crystallinity, homogeneity, and energy efficiency by using the oxygen-containing atmosphere is significantly reduced.

Irradiation of the laser beam is preferably performed by scanning a laser beam having a spot-shaped or linear-shaped cross section on the surface to be irradiated.

The laser beam preferably uses a pulse laser as a light source.

In order to carry out the present invention, the non-single-crystal silicon film is exposed to an oxygen-containing atmosphere, or the exposed state is heated or irradiated with ultraviolet rays to oxidize the upper surface of the non-single-crystal silicon film. Laser anneal with.

In one container, in an oxygen-containing atmosphere,
After oxidizing the upper surface of the non-single crystal silicon film, in another container,
Laser annealing may be performed in an oxygen-containing atmosphere or another atmosphere.

When laser annealing is performed in an oxygen-containing atmosphere in a container whose atmosphere can be controlled, oxidation and laser annealing can be performed in one container.
The manufacturing process is shortened. In this case, it is preferable to heat the substrate during laser annealing.

The silicon oxide film according to the present invention is a cap layer used in the conventional laser annealing process (oxidized on the amorphous silicon film during laser annealing mainly using a continuous wave laser having a small output). A silicon film or a silicon nitride film is formed by several thousand Å, and the mechanical strength of the film is completely different from the roughness (ridge) of the silicon film surface during laser annealing.

Such a thick silicon oxide film has a large output when a pulsed laser having a large output such as an excimer laser is used as in the present invention, as described above, during laser annealing.
A large amount of silicon oxide is mixed into the silicon film, which causes deterioration in film quality and characteristics of the crystalline silicon film formed.

When laser annealing is performed with the cap layer provided on the surface of the amorphous silicon film, crystallization is performed while being pressed by the cap layer. As a result, crystal growth is suppressed, and the crystallinity of the crystalline silicon film formed is lowered. In addition, a strong stress remains inside the crystalline silicon film.

In the present invention, since the silicon oxide film is extremely thin, crystal growth is hardly suppressed, higher crystallinity can be obtained as compared with the cap layer, and the internal stress can be made extremely small.

Therefore, the silicon oxide film according to the present invention is not suitable as a film having a mechanical strength enough to suppress the ridge. Since the silicon oxide film in the present invention is extremely thin, 100 Å or less,
Most of the silicon oxide film is scattered and removed.

[0049]

【Example】

Example 1 Example 1 shows an example in which laser annealing is performed on a non-single crystal silicon film in an oxygen-containing atmosphere. FIG. 2 shows a manufacturing process of the example. First, as a substrate 201, a silicon oxide film 202 as a base film of 2000 Å on a 127 mm square Corning 1737, and an amorphous silicon film of 500 Å thereon are continuously formed by plasma CVD. It

Next, a 10 ppm nickel acetate aqueous solution is applied on the amorphous silicon film by spin coating to form a nickel acetate layer. It is more preferable to add a surfactant to the nickel acetate aqueous solution. Since the nickel acetate layer is extremely thin, it is not always in the form of a film, but there is no problem in the subsequent steps.

Next, the substrate 201 on which each film is laminated as described above is subjected to thermal annealing at 600 ° C. for 4 hours to crystallize the amorphous silicon film and form the crystalline silicon film 203. It (Fig. 2 (A))

At this time, nickel, which is a catalytic element, plays a role of a nucleus for crystal growth and promotes crystallization. 600
The crystallization can be performed in a short time at a low temperature of 4 ° C. for 4 hours due to the function of nickel. Details are described in JP-A-6-244104.

The concentration of the catalytic element is preferably 1 × 10 ¹⁵ to 10 ¹⁹ atoms / cm ³ . 1 × 10 ¹⁹ atoms / cm ³
At the above high concentration, metallic properties appear in the crystalline silicon film,
The characteristics as a semiconductor disappear. In this embodiment, the concentration of the catalytic element in the crystalline silicon film is 1 × 10 ^{17 to} 5 × 10 ¹⁸ atoms / cm ^{3 as the} minimum value in the film. These values were analyzed and measured by secondary ion mass spectrometry (SIMS).

The crystalline silicon film 20 thus obtained
In order to further improve the crystallinity of No. 3, laser annealing is performed using an excimer laser.

FIG. 1 shows a laser irradiation chamber in the embodiment. FIG. 1 is a side sectional view of a laser irradiation chamber.

FIG. 3 shows a top view of the laser annealing apparatus in the embodiment. Here, the multi-chamber type laser annealing apparatus shown in FIG. 3 is used. The view showing the cross section AA ′ in FIG. 3 corresponds to FIG. 1.

In FIG. 1, the laser irradiation chamber 101 is
The pulse laser beam emitted from the laser oscillator 102 and processed into a linear cross section by the optical system 112 is reflected by the mirror 103, and the window 10 made of quartz is used.
4 has a function of irradiating the substrate 105 to be processed.

The laser oscillating device 102 is, here, X
One that oscillates an eCl excimer laser (wavelength 308 nm) is used. In addition, a KrF excimer laser (wavelength 2
48 nm).

The substrate 105 to be processed is placed on a stage 111 provided on a table 106, and a predetermined temperature (100 to 700) is set by a heater installed in the table 106.
° C).

The table 106 is moved by the moving mechanism 107 in the direction perpendicular to the line direction of the linear laser beam, and enables the upper surface of the substrate 105 to be processed to be irradiated with the laser beam while scanning.

Laser irradiation chamber 101 capable of controlling atmosphere
Has a vacuum exhaust pump 108 as a means for reducing pressure and exhausting. As a gas supply means, it has a gas supply pipe 109 connected to a hydrogen cylinder via a valve and a gas supply pipe 110 connected to a cylinder of nitrogen or another gas via a valve.

The laser irradiation chamber 101 includes a gate valve 3
01 is connected to the substrate transfer chamber 302.

In FIG. 3, the laser irradiation chamber 10 of FIG.
1 is connected to the substrate transfer chamber 302 via the gate valve 301.

The apparatus shown in FIG. 3 will be described. In the load / unload chamber 306, a cassette 312 containing a large number of substrates 105 to be processed, for example, 20 is arranged. The robot arm 305 moves one substrate from the cassette 312 to the alignment chamber.

The substrate 1 to be processed is placed in the alignment chamber 303.
05 and the robot arm 305 are arranged with an alignment mechanism for correcting the positional relationship. The alignment chamber 303 is connected to the load / unload chamber 306 via a gate valve 307.

The preheating chamber 308 is for preheating the substrate to be laser-annealed to a predetermined temperature to shorten the time required for heating the substrate in the laser irradiation chamber 101 and to improve the throughput. .

The inside of the preheating chamber 308 is made of cylindrical quartz. The cylindrical quartz is surrounded by a heater. Further, it is provided with a substrate holder made of quartz. The substrate holder is provided with a susceptor capable of accommodating a large number of substrates. The substrate holder is moved up and down by the elevator. The substrate is heated by the heater. The preheating chamber 308 is connected to the substrate transfer chamber 302 by a gate valve 309.

In the preheating chamber 308, the substrate preheated for a predetermined time is pulled back to the substrate transfer chamber 302 by the robot arm 305 and re-aligned in the alignment chamber 303, and then the laser irradiation chamber 101 is moved by the robot arm 305. Be transferred to.

After the laser irradiation is completed, the substrate 105 to be processed is drawn out to the substrate transfer chamber 302 by the robot arm 305 and transferred to the slow cooling chamber 310.

The slow cooling chamber 310 is connected to the substrate transfer chamber 302 via the gate valve 311, and the substrate 105 to be processed placed on the quartz stage is irradiated with infrared light from a lamp or a reflector. Bathed in and gradually cooled.

The substrate 10 to be processed which has been gradually cooled in the slow cooling chamber 310.
5 is transferred to the load / unload chamber 306 by the robot arm 305 and stored in the cassette 312.

Thus, the laser annealing process is completed. Thus, by repeating the above steps,
A large number of substrates can be processed one by one continuously.

A process of laser annealing using the apparatus shown in FIGS. 1 and 3 will be described. First, the target substrate 105
The (substrate 201 having the crystalline silicon film 203) is washed with an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ to remove the natural oxide film, and then stored in the cassette 312, and the cassette 312 is loaded / loaded. It is arranged in the unload chamber 306.

In FIG. 3, in the present embodiment, the substrate 10 to be processed conveyed from the load / unload chamber 306.
5 is to prevent oxidation by air in the preheating chamber,
After being aligned, it is not conveyed to the preheating chamber 308 but is directly conveyed to the laser irradiation chamber 101. However,
It is effective to heat in the preheating chamber 308 to such an extent that the upper surface of the crystalline silicon film 203 is not oxidized.

After the inside of the laser irradiation chamber 101 is evacuated by the vacuum exhaust pump 108, oxygen is supplied from the gas supply pipe 109 and nitrogen is supplied from the gas supply pipe 110, respectively, and an atmosphere of 20% oxygen and 80% nitrogen is created. Become. The purity of both oxygen and nitrogen supplied into the laser irradiation chamber is here 99.999999% (7N). At this time, the pressure is set to the atmospheric pressure.

The substrate 105 to be processed transferred to the laser irradiation chamber 101 is placed on the stage 111,
The heater in the table 106 heats for about 5 minutes to reach a temperature suitable for laser annealing, here 200 ° C. While being heated, the upper surface of the crystalline silicon film 203 is oxidized by oxygen in the atmosphere to form a pure silicon oxide film 204 free from impurities such as carbon in the air. The film thickness is 10 to 50Å, here, 30Å.

Further, in FIG. 1, the linear laser beam with which the substrate 105 to be processed is irradiated has a width of 0.34 mm ×
The length is 135 mm. The energy density of the laser beam on the irradiated surface is 100 mJ / cm ^{2 to} 500 m.
In the range of J / cm ² , for example, 260 mJ / cm ² . The linear laser beam is scanned by moving the table 106 in one direction at 2.5 mm / s. The oscillation frequency of the laser is set to 200 Hz, and focusing on one point of the object to be irradiated, a laser beam of 10 to 50 shots is irradiated.

In this way, the crystalline silicon film 203 is annealed by laser to improve the crystallinity.
(FIG. 2 (B))

Since the silicon oxide film 204 is extremely thin, most of it is scattered by the pulse laser irradiation a plurality of times.

Thereafter, the substrate 105 to be processed is cooled in the annealing chamber 310.
After being gradually cooled, it is stored in the cassette 312 of the load / unload chamber 306.

Since the air atmosphere is used during the slow cooling step, the upper surface of the crystalline silicon film 203 is easily oxidized during the slow cooling step.
Further, in laser annealing in an oxygen-containing atmosphere, even if the silicon oxide film 204 is scattered by a plurality of laser irradiations, the upper surface of the crystallized silicon film may be newly oxidized by oxygen in the atmosphere. . Further, even if the laser irradiation is performed, the silicon oxide film 204 may not be entirely scattered. As described above, since the silicon oxide film is likely to remain on the upper surface of the crystalline silicon film 203 after the laser annealing step, before the next step, a crystalline HF solution or a mixed aqueous solution of HF and H ₂ O ₂ is used. It is preferable to reduce the upper surface of the film 203 to remove the silicon oxide film.

Next, the crystalline silicon film formed in the above process is compared with the crystalline silicon film formed in another atmosphere. Similar to the method described above, the atmosphere during laser annealing and the energy density of the laser beam are changed to form a crystalline silicon film. The atmosphere is N ₂
/ H ₂ (3%) and N ₂ 100%. Each of the gases has a purity of 99.99999% (7N) or more, and the atmospheric pressure is atmospheric pressure.

FIG. 4 shows the relationship between the energy density of the laser beam and the Raman half-width at half maximum of the laser-annealed crystalline silicon film in laser annealing in various atmospheres. The Raman full width at half maximum refers to a value that is half the Raman full width at half maximum. In FIG. 4, the crystalline silicon film has an N ₂ / O ₂ content (20%) used in the above step as an oxygen-containing atmosphere.
Those prepared in the atmosphere are indicated by ⋄, those prepared in the N ₂ / H ₂ (3%) atmosphere are indicated by ∘, and those prepared in the N ₂ 100% atmosphere are indicated by □.

As shown in FIG. 4, the crystalline silicon film obtained by laser annealing in the oxygen-containing atmosphere of the present invention is:
It can be seen that Raman half-width at half maximum decreases with increasing energy density, that is, crystallinity improves.

Even if laser annealing is performed in an oxygen-containing atmosphere, if the laser energy density is too high, the crystallinity is improved, but the entire film is greatly roughened, making it difficult to use for devices such as thin film transistors. Become. Here, the laser energy density is preferably 270 mJ / cm ² or less.

On the other hand, in other atmospheres, the crystallinity remains low in the energy density range shown in FIG.

Laser annealing in the above-mentioned oxygen-containing atmosphere was performed under atmospheric pressure, not more than 0.01 Torr.
It may be performed under reduced pressure of not less than r and not more than 700 Torr.
By performing laser annealing under such a reduced pressure, it is possible to reduce the roughness of the surface of the annealed crystalline silicon film or the entire film.

Next, a thin film transistor (TFT) is produced using the produced crystalline silicon film 203. First, the crystalline silicon film 203 is etched to form island regions 205.

Next, a silicon oxide film to be the gate insulating film 206 is formed with a thickness of 1200Å by the plasma CVD method. TEOS and oxygen are used as source gases. The substrate temperature during film formation is 250 ° C. to 380 ° C., for example, 300 ° C. (Fig. 2 (C))

Next, a gate electrode is produced. Aluminum film is sputtered to a thickness of 3000Å ~ 8000
Å, for example, 6000Å is deposited. 0.1 to 2% of silicon may be contained in the aluminum film. The gate electrode 207 is formed by etching the film.

Next, impurities are added. In the case of manufacturing an N-channel TFT, phosphorus ions are implanted in the island region 205 by the ion doping method using the gate electrode as a mask. Phosphine (PH ₃ ) is used as a doping gas. The acceleration voltage is 10 to 90 kV, for example 80 kV, and the dose is 1 × 10 ^{14 to} 5 × 10 ¹⁵ atoms / cm ² , for example, 1 × 10 ¹⁵ atoms / cm ² . The substrate temperature is room temperature. As a result, the channel formation region 21
A source 208 and a drain 209 are formed as 0 and N-type impurity regions.

Further, in the case of manufacturing a P-channel type TFT, boron ions are implanted in the island region 205 by the ion doping method using the gate electrode 207 as a mask. As the doping gas, diborane (B ₂ H ₆ ) diluted with hydrogen to 1 to 10%, for example, 5% is used. The acceleration voltage is 60 to 90 kV, for example 65 kV, and the dose amount is
2 × 10 ^{15 to} 5 × 10 ¹⁵ atoms / cm ² , for example, 3 × 1
It is set to 0 ¹⁵ atoms / cm ² . The substrate temperature is room temperature. As a result, the source 208 and the drain 209 are formed as the channel formation region 210 and the P-type impurity region.
(Fig. 2 (D))

Next, in order to activate the doped impurities, laser annealing is performed again with a linear laser beam using the laser annealing apparatus shown in FIGS. The atmosphere in the laser irradiation chamber 101 is air (atmospheric pressure). The energy density of the laser beam on the irradiated surface is 100 mJ / cm ^{2 to} 350 mJ /
In the range of cm ² , for example, 160 mJ / cm ² . Scan a linear laser beam. Focusing on one point of the object to be irradiated, a laser beam of 20 to 40 shots is irradiated. The substrate temperature is 200 ° C. Then, thermal annealing is performed at 450 ° C. for 2 hours in a nitrogen atmosphere. (Figure 2
(E))

Subsequently, a silicon oxide film having a thickness of 6000 Å is formed by the plasma CVD method to form an interlayer insulating film 211. Next, a contact hole is formed in the interlayer insulating film 211 by etching. Further, by forming and etching a metal material, for example, a multilayer film of titanium and aluminum, the source electrode / wiring 212 and the drain electrode / wiring 213 are formed through the contact holes.

Finally, in a hydrogen atmosphere of 1 atm, 200 ~
A thermal annealing process at 350 ° C. is performed.

In this way, a plurality of N- or P-channel type crystalline TFTs are formed. These TFTs are
It is an excellent material having a mobility of 70 to 120 cm ² / Vs for the N channel type and 60 to 90 cm ² / Vs for the P channel type. (Fig. 2 (F))

Example 2 Example 2 shows an example in which a silicon oxide film is formed on the upper surface of a non-single crystal silicon film in an oxygen atmosphere, and then laser annealing is performed in a nitrogen atmosphere. In the second embodiment, the laser annealing device shown in FIG. 5 is used.
In the AA ′ cross section of the laser irradiation chamber 101 in FIG.
FIG. 1 corresponds.

The substrate 2 shown in FIG. 2 was manufactured in the same manner as in Example 1.
01, a substrate 105 on which a base film 202 and a crystalline silicon film 203 crystallized by thermal annealing are formed
However, after cleaning with a HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ to remove the natural oxide film, the cassette 312
The cassette 312 is stored in the loading / unloading chamber 3
It is located at 06.

The substrate 105 to be processed transferred from the load / unload chamber 306 is aligned and then transferred to the preheating chamber 501.

In the preheating chamber 501, as shown in FIG. 5, a vacuum exhaust pump 502 for depressurizing the space in which the substrate is placed and a gas capable of supplying oxygen and other gases to the space in which the substrate is placed. Supply pipes 503 and 504 are provided.

The vacuum exhaust pump 502 connected to the preheating chamber 501 evacuates the space in which the substrate is placed, and then oxygen is supplied from the gas supply pipe 503 and nitrogen is supplied from the gas supply pipe 504. , Inside the substrate holder,
Oxygen 5%, nitrogen 95% (both purity 99.99999 (7
N)) (atmospheric pressure) atmosphere is formed. And 50
When preheating is performed at ˜300 ° C., for example, 200 ° C., the silicon oxide film 204 is simultaneously formed at 20˜40 Å, for example, 30 Å.

The inside of the laser irradiation chamber 101 shown in FIG.
After being evacuated by the vacuum exhaust pump 108, nitrogen is supplied from the gas supply pipe 110, and nitrogen (purity 99.99) is supplied.
The atmosphere becomes 100% of 999% (7N). At this time, the pressure is set to the atmospheric pressure.

The substrate on which the silicon oxide film 204 is formed in the preheating chamber 501 is transferred to the laser irradiation chamber 101 after alignment. The substrate 10 to be processed conveyed
5 is heated to near 200 ° C., and the stage 111
In the state of being placed on top, the temperature suitable for laser annealing, here 200 ° C., is reached by heating for a very short time (several minutes) by the heater in the table 106.

Thereafter, laser annealing is performed under the same conditions as in Example 1 except for the atmosphere. In this way, the crystalline silicon film 203 is laser-annealed to improve the crystallinity. (FIG. 2 (B))

Since the silicon oxide film 204 is extremely thin, most of it is scattered by laser irradiation.

Thereafter, the substrate 105 to be processed is cooled in the slow cooling chamber 310.
After being gradually cooled, it is stored in the cassette 312 of the load / unload chamber 306.

Before proceeding to the next step, an HF aqueous solution or H
It is preferable to reduce the upper surface of the crystalline silicon film 203 with a mixed aqueous solution of F and H ₂ O ₂ to remove the silicon oxide film.

After that, as in the first embodiment, as shown in FIG.
According to (F), a thin film transistor is formed.

In the case of the second embodiment, the substrate 105 to be processed is carried into the laser irradiation chamber 101 in the same or different atmosphere as the preheating chamber 501, so that the time for forming the silicon oxide film is unnecessary, or the processing time is reduced. Laser annealing can be performed after shortening, and the manufacturing process can be shortened.

In the second embodiment, the atmosphere in the laser irradiation chamber 101 is the nitrogen atmosphere, but the nitrogen atmosphere is used. However, other atmospheres, for example, 20% oxygen and 80% nitrogen, as in the first embodiment. But it's okay.

However, laser annealing in a nitrogen atmosphere causes ridges (roughening of the surface of the crystalline silicon film after laser annealing) due to laser annealing, as compared with other air, oxygen-containing atmosphere, hydrogen-containing atmosphere and the like. Has the effect of suppressing

[Third Embodiment] In the third embodiment, as in the second embodiment, after the silicon oxide film 204 is formed on the upper surface of the crystalline silicon film 203 in the preheating chamber 501 shown in FIG. Instead, an example in which laser annealing is performed in air (atmospheric pressure) is shown.

Although the laser annealing is performed in the air, since the silicon oxide film 204 is formed, the silicon oxide film 20 is formed.
It is possible to perform laser annealing having excellent crystallinity, homogeneity, and energy utilization efficiency as compared with the case where laser annealing is simply performed in air without forming No. 4.

The laser irradiation chamber 101, which is a container in which the atmosphere can be controlled, may be omitted if the atmosphere is not particularly controlled.

[Embodiment 4] In Embodiment 1, a step of forming a crystalline silicon film 203 by thermal crystallization (FIG. 2).
In (A)), the upper surface of the crystalline silicon film 203 is oxidized by a slow cooling step (air atmosphere) after thermal crystallization, and a silicon oxide film is formed in the order of several tens of liters. In the first embodiment, the silicon oxide film is removed by cleaning before the laser annealing process, but in the fourth embodiment, the silicon oxide film is not removed and the laser annealing device shown in FIG. Anneal.

When laser annealing is performed on the crystalline silicon film 203 in a nitrogen atmosphere similar to that in the second embodiment, the laser annealing is performed in a nitrogen atmosphere without forming a silicon oxide film. Compared with, the crystallinity, its homogeneity, and the utilization efficiency of laser energy are significantly improved.

[Embodiment 5] In Embodiment 5, an example of the continuous processing apparatus used in Embodiment 6 is shown. This continuous processing device
The non-single crystal silicon film cleaning step and the laser annealing step or the heating (silicon oxide film formation) step can be successively performed without being exposed to the air. FIG. 6 shows a top view of the continuous processing apparatus in the example. The apparatus shown in FIG. 6 has a configuration in which a substrate cleaning chamber is added to the apparatus shown in FIG.

In FIG. 6, the substrate transfer chamber 601 includes a laser irradiation chamber 602, a preheating chamber 603, and a slow cooling chamber 60.
4. The cleaning chamber 607 is connected via gate valves 608 to 611. A load / unload chamber 605 is connected to the substrate transfer chamber 601 via an alignment chamber 606 and a gate valve 612.

In the substrate transfer chamber 601, a robot arm 613 is arranged as a substrate transfer means for transferring the substrate 600. In the load / unload chamber 605, a cassette 615 that accommodates a plurality of substrates is arranged.

In the structure shown in FIG. 6, the substrate transfer chamber 60
The description of the laser irradiation chamber 602, the preheating chamber 603, the slow cooling chamber 604, the load / unload chamber 605, and the alignment chamber 606 is omitted because it has the same configuration as the device illustrated in FIG.

Further, the apparatus shown in FIG. 6 maintains the airtightness between each chamber. Further, gas supply means and exhaust means (not shown) are provided in each chamber, and the atmosphere and pressure in each chamber can be controlled arbitrarily. A substrate processed by such an apparatus is shielded from the outside atmosphere, and thus can be prevented from being exposed to the atmosphere.

In FIG. 6, a cleaning chamber 607 is provided with a stage 616, a cup 617, and a cleaning liquid outflow nozzle 618. The stage 616 vacuum-sucks and fixes the back surface of the substrate transferred into the cleaning chamber 607, and horizontally rotates the substrate. The cleaning liquid outflow nozzle 618 causes the cleaning liquid to flow out to the center of the substrate rotation surface.

As the cleaning liquid, HF and H ₂ O ₂ were mixed with each other.
An aqueous solution or the like mixed by 5 wt% is preferable. HF
You may use the aqueous solution of. This cleaning liquid removes the natural oxide film, impurities, etc. on the upper surface of the non-single crystal silicon film.

The cup 617 is arranged so as to surround the periphery of the substrate when the substrate rotates. When the substrate is transferred, it is arranged below the substrate fixing position on the upper surface of the stage so as not to interfere with the transfer. The cup 617 receives the cleaning liquid scattered around by the rotation of the substrate and discharges it downward.

The cleaning process by the apparatus shown in FIG. 6 will be described. The substrate 614 is transferred into the cleaning chamber, and the stage 6
After being vacuum-adsorbed and fixed on the upper surface of 16, the substrate rotates at a predetermined rotation speed. At this time, the cleaning liquid outflow nozzle 61
From 8, the cleaning liquid flows out to the center of the substrate rotation surface.

The cleaning liquid that has flowed out is concentrically spread outward from the center of the substrate by the centrifugal force, reaches the periphery of the substrate, is scattered into the cup 617, and is then discharged.

After maintaining such a state for several tens of seconds to several minutes, the outflow of the cleaning liquid is stopped, the rotation speed of the substrate is increased, and the cleaning liquid is dried.

Thus, the cleaning process is completed. After that, the substrate 604 is moved to another chamber such as a preheating chamber or a laser irradiation chamber by the transfer means 613.

Using the apparatus shown in FIG. 6, a substrate cleaning step, that is, a step of removing a natural oxide film, impurities, dust, etc. on the upper surface of the non-single crystal silicon film, a laser annealing step in an oxygen atmosphere for the non-single crystal silicon film, or an oxygen The heating step (oxide film forming step) in the atmosphere can be continuously performed without exposing to the atmosphere.

As a result, the thin silicon oxide film formed on the upper surface of the non-single-crystal silicon film can be made of good quality without impurities, and good crystallization can be performed by laser annealing.

Further, by using the apparatus shown in FIG. 6, it is possible to continuously wash the upper surface of the crystalline silicon film after the laser annealing process. As a result, a crystalline silicon film having a clean surface can be provided in a shorter period of time after the laser annealing process, which contributes to a reduction in manufacturing time.

In this embodiment, the cleaning of the substrate is performed by rotating the substrate using the cleaning liquid. In this method, since the cleaning liquid is extremely unlikely to adhere to the back surface of the substrate, it is possible to prevent the glass substrate from being fogged or contaminated by the cleaning liquid. Furthermore, since the cleaning liquid can be dried only by rotating the substrate, the entire cleaning process can be shortened. Further, since the equipment is compact and simple, it is effective to use it in a multi-chamber type continuous processing apparatus as shown in FIG. 6 in order to reduce the installation area of the apparatus and to facilitate the design.

However, the substrate cleaning method of this embodiment is not limited to this. For example, without rotating the substrate,
The cleaning liquid may flow out onto the upper surface of the substrate.

The non-single crystal silicon film may be exposed to a reducing gas atmosphere.

[Sixth Embodiment] In a sixth embodiment, an example in which the apparatus of FIG. 6 is used and the substrate cleaning step and the laser annealing step are continuously performed without being exposed to the atmosphere will be described.

The manufacturing process of the thin film transistor of Example 6 will be described with reference to FIGS. First, in the same manner as in Example 1, as a substrate 201, a silicon oxide film 202 as a base film of 2000 Å on a 127 mm square Corning 1737, and an amorphous silicon film of 500 Å thereon, both of which were formed by plasma CVD.
Film is continuously formed by the method.

Next, the same nickel acetate aqueous solution as in Example 1 is applied, and then thermal annealing is performed at 600 ° C. for 4 hours to form a crystalline silicon film 203. ((Figure 2
(A))

Next, with the continuous processing apparatus shown in FIG. 6, the cleaning of the crystalline silicon film and the laser annealing process in an oxygen atmosphere are continuously performed.

Each chamber of the continuous processing apparatus shown in FIG. 6 is isolated from the atmosphere, and the atmosphere is made of clean gas from which impurities and the like have been removed. For example, an inert gas such as nitrogen, argon, or helium, or a mixture of these with oxygen is preferable. Alternatively, purified air may be used.

First, the substrate to be processed on which the crystalline silicon film 203 is formed is placed in the cassette 615, and the cassette 61
5 is placed in the load / unload chamber 606.

The substrate to be processed transferred from the load / unload chamber 606 is aligned in the alignment chamber 605 and then transferred to the cleaning chamber 607, where the crystalline silicon film 2 is transferred.
The natural oxide film and impurities on the upper surface of 03 are removed.

In the cleaning chamber 607, the substrate 614 is fixed to the stage 616, and is cleaned with a cleaning liquid while rotating.

The cleaning liquid for cleaning flows out from the nozzle 618 to the central portion of the rotating surface of the substrate. The cleaning liquid moves concentrically from the center of the substrate toward the periphery due to the centrifugal force generated by the rotation of the substrate. After that, the cleaning liquid is scattered around the substrate, hits the cup 617, and is then discharged. As the cleaning liquid, an aqueous solution containing HF and H ₂ O _{2 in an amount} of 0.5 wt% is used here. Alternatively, an HF aqueous solution may be used.

The substrate receives the cleaning liquid for 10 seconds to 5 seconds.
It is rotated at a rotation speed of 100 to 1000 rpm, for example, 300 rpm for one minute, here, for one minute. After that, the outflow of the cleaning liquid is stopped, and in order to dry the upper surface of the substrate, the substrate rotation speed is increased and the substrate is rotated for about 30 seconds. The substrate rotation speed during drying is 25
It was set to 00 to 4000 rpm, here 3000 rpm.

After that, the rotation of the substrate is stopped, and the substrate is unloaded from the cleaning chamber 607 by the substrate transfer means 613.

In this way, the crystalline silicon film 2 on the substrate is
The upper surface of 03 is cleaned to remove the natural oxide film and impurities.

Next, laser annealing is performed on the crystalline silicon film 203. The substrates carried out from the cleaning chamber 607 are
Directly to the laser irradiation chamber 602 or the preheating chamber 60
After being heated at 3, it is conveyed.

As a result, the crystalline silicon film after cleaning is not exposed to the atmosphere and the laser irradiation chamber 60 is continuously subjected to the cleaning process.
2 is transferred.

Further, the substrate heating time in the laser irradiation chamber can be shortened by heating the substrate to the laser irradiation chamber after heating it to a predetermined temperature using the preheating chamber 603.

Next, laser annealing is performed in an oxygen atmosphere. The laser irradiation chamber 602 has 20% oxygen and 8 nitrogen.
An atmosphere of 0% is constructed. Then, under the same conditions as in Example 1, the crystalline silicon film 203 is laser-annealed in an oxygen atmosphere to improve the crystallinity.
(FIG. 2 (B))

In this embodiment, the substrate to be processed is exposed to the atmosphere at all from the previous cleaning step to the laser annealing step by using the continuous processing apparatus of FIG. 6, and is exposed only to a clean atmosphere without impurities. Therefore, the natural oxide film formed in the air and impurities in the air are considerably removed in and around the thin silicon oxide film 204 formed on the upper surface of the crystalline silicon film 203 in the laser annealing process. As a result, the silicon oxide film 204 becomes an extremely pure silicon oxide film, and the laser annealing can be performed more effectively as compared with the first embodiment.

That is, the thin silicon oxide film 20 to be formed
The film thickness and film quality of No. 4 are more uniform on the upper surface of the crystalline silicon film 203 as compared with the case of Example 1, and as a result,
The uniformity of the film quality of the film crystallized by laser annealing in the plane of the substrate is improved.

Furthermore, the penetration of impurities into the crystalline silicon film 203 during laser annealing is further reduced. As a result, various characteristics of the manufactured thin film transistor, such as mobility and threshold value, can be made more stable within the substrate surface and between lots.

After the laser annealing process is completed, the substrate is transported to the slow cooling chamber 604 and gradually cooled if necessary.

After that, the substrate may be transferred to the load / unload chamber, but the silicon oxide film is likely to remain on the upper surface of the crystalline silicon film 203 after the laser annealing process is completed.

That is, in laser annealing in an oxygen-containing atmosphere, the silicon oxide film 2 is irradiated by laser irradiation a plurality of times.
Even if 04 is scattered, the upper surface of the crystallized silicon film may be newly oxidized by oxygen in the atmosphere. Also,
In some cases, even if the laser irradiation is performed, the entire silicon oxide film 204 is not scattered.

Therefore, it is extremely effective to carry the substrate again to the cleaning chamber after the laser annealing process, and to perform the cleaning.

In the process, the substrate is placed in the laser irradiation chamber 60.
2 or after being unloaded from the slow cooling chamber 604, loaded into the washing chamber 607 to wash the upper surface of the crystalline silicon film 203 to remove the silicon oxide film and impurities. The conditions are the same as in the cleaning step before the laser annealing step.

As described above, the laser annealing step and the cleaning step are continuously performed, or the annealing step and the cleaning step are continuously performed without exposing to the atmosphere, so that high cleanliness of the upper surface of the crystalline silicon film can be obtained in a short time. You can

After that, the substrate for which the cleaning process has been completed is transferred from the cleaning chamber 607 to the loading / unloading chamber 606 by the substrate transfer means 613 and stored in the cassette 615.

Then, the thin film transistor is completed by the same steps as in the first embodiment. (FIG. 2 (C) -FIG. 2
(F))

The thin film transistor thus manufactured has improved characteristics and is stable in the plane of the substrate and between lots.

[Embodiment 7] In Embodiment 7, using the continuous processing apparatus of FIG. 6, after forming a silicon oxide film on the upper surface of a non-single crystal silicon film in an oxygen atmosphere, laser annealing is performed in a nitrogen atmosphere. An example of applying is shown.

A thin film transistor is manufactured according to FIG. 2 in the same manner as in Example 6. A silicon oxide film 202 as a base film and an amorphous silicon film are continuously formed on a substrate 201,
After applying the nickel acetate aqueous solution, thermal annealing is performed at 600 ° C. for 4 hours to form the crystalline silicon film 203.
((Figure 2 (A))

Next, using the continuous processing apparatus shown in FIG.
Similar to the sixth embodiment, the upper surface of the crystalline silicon film 203 is cleaned in the cleaning chamber 607. As a result, the natural oxide film and impurities on the upper surface of the crystalline silicon film 203 are removed.

Next, the substrate is transferred to the preheating chamber 603. In the preheating chamber 603, an atmosphere of 5% oxygen and 95% nitrogen (both in purity 99.99999 (7N)) (atmospheric pressure) is formed. And 50 to 300 ° C., for example, 2
When preheating is performed at 00 ° C., a thin silicon oxide film 204 is formed on the upper surface of the crystalline silicon film 203 by 20 to 40 Å, for example, 30 Å.
It is formed.

The silicon oxide film 204 formed here is an extremely pure film with less impurities mixed in because the upper surface of the crystalline silicon film 203 was cleaned by the previous cleaning step and was not exposed to the atmosphere. .

After the preheating is completed, the substrate to be processed is transferred from the preheating chamber 603 to the laser irradiation chamber 602 without being exposed to the atmosphere. The inside of the laser irradiation chamber 602 is a nitrogen atmosphere here.

Laser annealing is performed under the same conditions as in Example 6 except for the atmosphere, and the crystalline silicon film 203
The crystallinity of is improved. (FIG. 2 (B))

Crystalline silicon film 203 after laser annealing
In comparison with that obtained in Example 2, the uniformity of crystallization by laser annealing in the plane of the substrate is improved. Further, various characteristics such as mobility and threshold value of the manufactured thin film transistor are more stable within the substrate surface and between lots.

Further, the atmosphere at the time of laser annealing is a nitrogen atmosphere, so that the generation of ridges can be suppressed as compared with the oxygen atmosphere. As a result, in addition to improving the crystallinity and film quality of the crystalline silicon film obtained by continuously performing the cleaning process and the laser annealing process without exposing the substrate to the atmosphere, the ridge is suppressed and the crystalline silicon film The film quality can be made more excellent.

After this, as in the sixth embodiment, FIG.
According to (F), a thin film transistor is formed.

In the process of this embodiment, the time required for forming the silicon oxide film 204 in the laser irradiation chamber is not required, as in the second embodiment. Therefore, the manufacturing process time can be shortened.

In the present embodiment, even if the atmosphere during laser annealing is other than the nitrogen atmosphere, it can be carried out as long as it is a clean atmosphere.

[0175]

According to the present invention, the crystallinity and homogeneity can be greatly improved, and the energy utilization efficiency can be greatly improved, as compared with the case where laser annealing is performed in another atmosphere including air.

[Brief description of the drawings]

FIG. 1 is a diagram showing a laser irradiation chamber in an example.

FIG. 2 is a diagram showing a manufacturing process of an example.

FIG. 3 is a top view of the laser annealing apparatus according to the embodiment.

FIG. 4 shows laser annealing in various atmospheres.
The figure which shows the relationship between the energy density of a laser beam, and the Raman half width at half maximum of the crystalline silicon film which carried out laser annealing.

FIG. 5 is a top view of the laser annealing apparatus in the example.

FIG. 6 is a top view of the continuous processing apparatus according to the embodiment.

[Explanation of symbols]

 101 Laser Irradiation Chamber 102 Laser Oscillator 103 Mirror 104 Window 105 Processed Substrate 106 Units 107 Moving Mechanism 108 Vacuum Evacuation Pump 109, 110 Gas Supply Pipe 111 Stage 112 Optical System 201 Substrate 202 Silicon Oxide Film (Base Film) 203 Crystallized Silicon Film 204 Silicon oxide film 205 Island region 206 Gate insulating film 207 Gate electrode 208 Source 209 Drain 210 Channel forming region 211 Interlayer insulating film 212 Source electrode / wiring 213 Drain electrode / wiring 301 Gate valve 302 Substrate transfer chamber 303 Alignment chamber 305 Robot Arm 306 Load / unload chamber 307 Gate valve 308 Preheating chamber 309 Gate valve 310 Slow cooling chamber 311 Gate valve 312 Cassette 501 Preheating chamber 502 True Empty exhaust pumps 503, 504 Gas supply pipe 601 Substrate transfer chamber 602 Laser irradiation chamber 603 Preheating chamber 604 Slow cooling chamber 605 Load / unload chamber 606 Alignment chamber 607 Cleaning chamber 608 to 612 613 Robot arm 614 Substrate 615 Cassette 616 Stage 617 Cup 618 nozzle

Claims (6)

[Claims] 1. A first step of cleaning a non-single-crystal silicon film formed on a substrate, and a second step of laser-annealing the non-single-crystal silicon film in an atmosphere containing oxygen. A laser annealing method, wherein the first step and the second step are continuously performed without being exposed to the atmosphere. 2. The laser annealing method according to claim 1, wherein the second step is performed after the upper surface of the non-single-crystal silicon film is oxidized in the atmosphere containing oxygen. 3. A first step of cleaning a non-single-crystal silicon film formed on a substrate, a second step of oxidizing an upper surface of the non-single-crystal silicon film to form a silicon oxide film, Third laser annealing for non-single crystal silicon film
And a step of performing at least the first step and the second step of the above steps, which are continuously performed without being exposed to the atmosphere. 4. The laser annealing method according to claim 3, wherein the third step is performed in a nitrogen atmosphere. 5. A laser annealing apparatus having at least a cleaning chamber and a laser irradiation chamber, wherein a substrate to be processed is transported without being exposed to the atmosphere between the chambers. 6. A cleaning chamber, a preheating chamber, and a laser irradiation chamber are provided at least, and the substrate to be processed is transported between the cleaning chamber and the preheating chamber without being exposed to the atmosphere. Laser annealing equipment.