JP3927634B2 - Laser annealing method and thin film transistor manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of crystallizing or improving crystallinity by applying laser annealing to an amorphous silicon film or a crystalline silicon film formed on an insulating substrate such as glass.
[0002]
[Prior art]
In recent years, an amorphous silicon film or a crystalline silicon film (a silicon film having crystallinity such as polycrystalline or microcrystalline) that is formed over an insulating substrate such as glass, that is, a non-single-crystal silicon film is used. On the other hand, a technique for performing laser annealing to crystallize or improve crystallinity has been widely studied.
[0003]
Since the crystalline silicon film formed by laser annealing has high mobility, a thin film transistor (TFT) is formed using this crystalline silicon film. For example, on a single glass substrate, for driving a pixel. It is actively used in monolithic liquid crystal electro-optical devices and the like for producing TFTs for driving circuits.
[0004]
In addition, a laser beam is produced by processing a pulse laser beam such as an excimer laser having a high output with an optical system so that a square spot of several centimeters square or a line of several millimeters wide × several tens of centimeters is formed on the irradiated surface. The method of performing laser annealing by moving the laser beam (moving the irradiation position of the laser beam relative to the surface to be irradiated) is preferable because it is excellent in mass productivity and industrially excellent.
[0005]
In particular, when a linear laser beam is used, the entire irradiated surface is irradiated by scanning only in a direction perpendicular to the linear direction, unlike when using a spot laser beam that requires scanning in the front, rear, left, and right directions. Therefore, high mass productivity can be obtained.
[0006]
[Problems to be solved by the invention]
Several problems have arisen when laser annealing is performed on a non-single-crystal silicon film by scanning a spot-like or linear laser beam using a pulsed laser beam as a light source.
[0007]
For example, when laser annealing is performed in the air, carbon and other impurities contained in the air are likely to be mixed into the coating, and various properties such as film quality, crystallinity, and mobility of the crystalline silicon film after annealing are reduced. There's a problem.
[0008]
In addition, in an inert gas atmosphere such as vacuum or nitrogen, scanning with a laser beam with a spot-like or linear shape on the irradiated surface and performing laser annealing, compared to annealing in air, the following There are problems.
[0009]
(1) Poor crystallinity. That is, high crystallinity cannot be obtained unless the energy density of the laser is significantly increased as compared with annealing in air.
[0010]
(2) The homogeneity of the crystal within the film surface is poor. Places with good crystallinity and places with poor crystallinity are distributed in the film plane. For example, when a linear laser beam is scanned in a direction perpendicular to the linear direction of the beam, a place with good crystallinity and a place with bad crystallinity appear in a striped pattern in the film surface. Accordingly, when a plurality of thin film transistors are manufactured using the manufactured crystalline silicon film, characteristics such as a threshold value and mobility vary depending on the position of the thin film transistor on the substrate.
[0011]
(3) Energy use efficiency is poor. In order to increase crystallinity, it is necessary to increase the energy density of the laser. When the energy density is increased, the power consumption increases, and in addition, the entire laser irradiation device including the laser oscillator, circuit, gas, and optical system is heavily consumed. Therefore, the cost of the device to be manufactured is increased. On the other hand, when the energy density of the laser increases, the crystallinity increases, but the entire film after laser annealing is severely roughened, and it becomes difficult to fabricate a device by processing the film.
[0012]
The present invention solves the above problems.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, one of the main configurations disclosed in this specification is as follows:
A first step of cleaning the non-single-crystal silicon film formed on the substrate;
A second step of laser annealing the non-single crystal silicon film in an atmosphere containing oxygen;
The laser annealing method is characterized in that the first step and the second step are continuously performed without being exposed to the atmosphere.
[0014]
In the above structure, the second step is preferably performed after the upper surface of the non-single-crystal silicon film is oxidized in the oxygen-containing atmosphere.
[0015]
One of the other configurations is
A first step of cleaning the non-single-crystal silicon film formed on the substrate;
A second step of forming a silicon oxide film by oxidizing the upper surface of the non-single-crystal silicon film;
A third step of laser annealing the non-single-crystal silicon film,
Of the steps, at least the first step and the second step are continuously performed without being exposed to the atmosphere.
[0016]
In the above structure, the third step is preferably performed in a nitrogen atmosphere.
[0017]
One of the other configurations is
Having at least a cleaning chamber and a laser irradiation chamber,
In the laser annealing apparatus, the substrate to be processed is transported between the chambers without being exposed to the atmosphere.
[0018]
One of the other configurations is
Having at least a cleaning chamber, a preheating chamber, and a laser irradiation chamber;
In the laser annealing apparatus, the substrate to be processed is transported between the cleaning chamber and the preheating chamber without being exposed to the atmosphere.
[0019]
In this specification, “continuous” means that there is no step between the first step and the second step in which impurities or other undesirable substances adhere to the non-single-crystal silicon film.
[0020]
Therefore, for example, between the first step and the second step, the substrate transfer step, the alignment step, the slow cooling step, the step of heating the substrate to the temperature required for the second step, the dehydrogenation step by heating, etc. Having can be said to be in the continuous range herein.
[0021]
On the other hand, the steps of exposing the non-single crystal silicon film to a specific atmosphere that changes the film quality, steps such as ion doping, film formation, etching, plasma treatment, and coating are between the first step and the second step. In this case, the definition of continuity in this specification does not apply.
[0022]
In the present invention, when laser annealing is performed on a non-single crystal silicon film to improve crystallization or crystallinity, the upper surface of the non-single crystal silicon film is oxidized in an oxygen-containing atmosphere, and is particularly less than 100 mm. A silicon oxide film having a thickness is formed, and then a laser beam is irradiated.
[0023]
In addition, laser irradiation is performed on the non-single crystal silicon film in a state where the film is arranged in an atmosphere containing oxygen.
[0024]
Further, the step of cleaning the non-single-crystal silicon film to remove a natural oxide film and impurities, the step of irradiating the non-single-crystal silicon film with a laser in an atmosphere containing oxygen, or the non-single crystal in an atmosphere containing oxygen. The step of forming the silicon oxide film on the upper surface of the crystalline silicon film is continuously performed without being exposed to the atmosphere.
[0025]
When the upper surface of the non-single crystal silicon film is oxidized to form a silicon oxide film having a thickness of 100 mm or less, and laser annealing is performed in this state, a pure crystalline silicon film can be obtained only by laser annealing in air. In addition, as compared with the case where laser annealing is performed in another atmosphere including air, excellent characteristics are produced in the following points.
(1) The crystallinity of the crystalline silicon film is improved.
(2) The crystallinity of the crystalline silicon film is made uniform in the film plane.
(3) The energy density of the laser necessary for crystallization is lowered.
[0026]
By providing this extremely thin silicon oxide film, it is considered that the reflection / release of the energy of the laser beam applied to the non-single crystal silicon film is suppressed and the applied energy is maintained in the film. For this reason, more energy can be given than in the case where a non-single-crystal silicon film is not provided with a silicon oxide film, and crystallinity is improved.
[0027]
At the same time, since unevenness and variation in energy density for each pulse of the laser beam are homogenized, the crystallinity is also homogenized in the film plane.
[0028]
Furthermore, since the reflection / release of laser energy into the atmosphere is reduced and the energy is effectively used for crystallization, the energy density of the irradiated laser beam can be reduced.
[0029]
If the energy density of the laser beam is set to a high value similar to the state without the silicon oxide film in a state where the silicon oxide film is provided on the non-single-crystal silicon film, the extra energy is reduced due to less energy loss. However, although the crystallinity is increased, the entire film is severely roughened. It is extremely difficult to manufacture a device such as a thin film transistor using such a film.
[0030]
In addition, before laser annealing, HF aqueous solution, HF, H ₂ O ₂ It is preferable to clean the upper surface of the non-single-crystal silicon film with an aqueous solution containing and remove the natural oxide film. The subsequent silicon oxide film preparation step or laser annealing step in an oxygen-containing atmosphere is preferably performed while heating the substrate, because the formation rate of the silicon oxide film is improved. You may irradiate with ultraviolet rays.
[0031]
In particular, this cleaning process and the subsequent laser annealing process in an oxygen atmosphere are performed continuously without exposure to the air, or the cleaning process and the heating (oxygen film silicon film formation) process in an oxygen atmosphere, laser annealing. It is preferable to perform the process continuously without exposure to the atmosphere.
[0032]
By doing so, the extremely clean upper surface of the non-single-crystal silicon film can be a 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.
[0033]
Furthermore, 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 stabilized both in the substrate surface and between lots.
[0034]
As the atmosphere containing oxygen, oxygen alone or a mixed gas of oxygen and an inert gas such as nitrogen, helium, or argon is preferable. In the mixed gas, it is desirable that oxygen is contained at 1% or more, more preferably 5% or more under atmospheric pressure. When the oxygen content is less than 1%, the time required to form a sufficient silicon oxide film becomes very long or no longer formed, and the effects of the present invention cannot be obtained sufficiently, which is not practical. If the oxygen content is 5% or more, the effects of the present invention can be obtained stably.
[0035]
When air is used as the atmosphere containing oxygen when forming the silicon oxide film, impurities such as carbon in the air are mixed in the annealed film, and the mobility and other characteristics of the crystalline silicon film are In many cases, the deterioration or characteristics of each lot becomes unstable.
However, it is effective to perform laser annealing in an air atmosphere after forming a silicon oxide film in another atmosphere.
[0036]
The purity of the oxygen or inert gas constituting the atmosphere containing oxygen is particularly preferably 99.9% (3N) or more and 99.99999% (7N) or less. By using an atmosphere using such a purity gas, carbon, water, hydrocarbons, and other impurities are prevented from entering the crystalline silicon film, and the film quality and film characteristics are stable and have excellent characteristics. A crystalline silicon film is obtained. If the purity of oxygen or inert gas constituting the atmosphere is less than 3N, there is almost no difference from the case where an air atmosphere is used, and the film characteristics are likely to be unstable due to impurities. Also, using a material having a purity higher than 7N is not preferable because the effect is not much different from that in the case of 7N or less and only the cost is increased.
[0037]
If the thickness of the silicon oxide film is 100 mm or more, the amount of silicon oxide film mixed into the crystalline silicon film is increased by laser irradiation, and various characteristics such as crystallinity and mobility of the crystalline silicon film are exhibited. It will decline. On the other hand, if the film thickness is too thin, such as about 5 mm or less, the effects of the present invention described above are significantly reduced. The film thickness of the silicon oxide film is 5 to 100 mm, preferably 10 to 50 mm, and more preferably 20 to 40 mm.
[0038]
The pressure during laser annealing may be atmospheric pressure. In addition, when the pressure during laser annealing is reduced to atmospheric pressure or less, particularly 0.01 Torr or more and 700 Torr or less, the upper surface of the crystalline silicon film or the entire film is less rough due to multiple irradiations of the pulse laser. It 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 at the time of laser annealing is larger than 700 Torr, the roughness of the film hardly changes from atmospheric pressure. When the pressure is less than 0.01 Torr, the effects of improving the crystallinity, homogeneity, and energy efficiency due to the use of the oxygen-containing atmosphere are significantly reduced.
[0039]
The laser beam irradiation is preferably performed by scanning a laser beam having a spot-like or linear cross-sectional shape on the irradiated surface.
[0040]
The laser beam preferably uses a pulse laser as a light source.
[0041]
In carrying out the present invention, the non-single crystal silicon film is exposed to an oxygen-containing atmosphere, or heated or irradiated with ultraviolet rays in the exposed state to oxidize the upper surface of the non-single crystal silicon film, and laser annealing is performed in that state. To do.
[0042]
After oxidizing the upper surface of the non-single crystal silicon film in an oxygen-containing atmosphere in one container, laser annealing may be performed in an oxygen-containing atmosphere or another atmosphere in another container.
[0043]
Further, when laser annealing is performed in an oxygen-containing atmosphere in a container in which atmosphere control is possible, oxidation and laser annealing can be performed in one container, and the manufacturing process is shortened. In this case, it is preferable to heat the substrate during laser annealing.
[0044]
The silicon oxide film according to the present invention is a cap layer used in a conventional laser annealing process (mainly a silicon oxide film or an oxide film on an amorphous silicon film during laser annealing using a continuous wave laser with a small output). Thousands of silicon nitride films are formed, and the mechanical strength of the film is completely different from that for preventing the roughness (ridge) of the silicon film surface during laser annealing.
[0045]
Such a thick silicon oxide film is formed by mixing a large amount of silicon oxide in the silicon film during laser annealing as described above when a pulse laser having a high output such as an excimer laser is used as in the present invention. The film quality and characteristics of the crystalline silicon film are reduced.
[0046]
Further, when laser annealing is performed in a state where a cap layer is provided on the surface of the amorphous silicon film, crystallization is performed while being pressed down by the cap layer. As a result, crystal growth is suppressed and the crystallinity of the formed crystalline silicon film is lowered. Also, a strong stress remains in the crystalline silicon film.
[0047]
In the present invention, since the silicon oxide film is extremely thin, crystal growth is hardly suppressed, high crystallinity is obtained as compared with the cap layer, and internal stress can be extremely reduced.
[0048]
Accordingly, the silicon oxide film according to the present invention is not suitable for a film thickness that provides sufficient mechanical strength to suppress ridges. Since the silicon oxide film according to the present invention is extremely thin at 100 mm or less, most of the silicon oxide film is scattered and removed by multiple times of pulse laser irradiation.
[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 is formed on a 127 mm square Corning 1737, and an amorphous silicon film is formed on it in a continuous manner by a plasma CVD method. The
[0050]
Next, a 10 ppm nickel acetate aqueous solution is applied onto the amorphous silicon film by a spin coating method 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 a film, but there is no problem in the subsequent steps.
[0051]
Next, the substrate 201 on which the respective films are laminated as described above is subjected to thermal annealing at 600 ° C. for 4 hours, and the amorphous silicon film is crystallized to form the crystalline silicon film 203. (Fig. 2 (A))
[0052]
At this time, the catalytic element nickel serves as a nucleus for crystal growth and promotes crystallization. The reason that crystallization can be performed at 600 ° C. for 4 hours at a low temperature is due to the function of nickel. Details are described in JP-A-6-244104.
[0053]
The concentration of the catalytic element is 1 × 10 ¹⁵ -10 ¹⁹ Atom / cm ^Three Is preferable. 1 × 10 ¹⁹ Atom / cm ^Three At the above high concentration, metallic properties appear in the crystalline silicon film and the characteristics as a semiconductor disappear. In this embodiment, the concentration of the catalytic element in the crystalline silicon film is the minimum value in the film and is 1 × 10. ¹⁷ ~ 5x10 ¹⁸ Atom / cm ^Three It is. These values are analyzed and measured by secondary ion mass spectrometry (SIMS).
[0054]
In order to further improve the crystallinity of the crystalline silicon film 203 thus obtained, laser annealing is performed using an excimer laser.
[0055]
FIG. 1 shows a laser irradiation chamber in the embodiment. FIG. 1 is a side sectional view of a laser irradiation chamber.
[0056]
FIG. 3 shows a top view of the laser annealing apparatus in the embodiment. Here, a multi-chamber laser annealing apparatus shown in FIG. 3 is used. The figure which shows the AA 'cross section in FIG. 3 corresponds to FIG.
[0057]
In FIG. 1, a laser irradiation chamber 101 is irradiated with a pulse laser beam irradiated from a laser oscillating device 102 and processed into a linear cross section by an optical system 112 by a mirror 103, and a window 104 made of quartz is formed. Through this, the substrate 105 to be processed is irradiated.
[0058]
Here, the laser oscillation device 102 uses an XeCl excimer laser (wavelength 308 nm) that oscillates. In addition, a KrF excimer laser (wavelength 248 nm) may be used.
[0059]
The substrate 105 to be processed is placed on a stage 111 provided on a table 106 and is maintained at a predetermined temperature (100 to 700 ° C.) by a heater installed in the table 106.
[0060]
The stage 106 is moved in a direction perpendicular to the linear direction of the linear laser beam by the moving mechanism 107 and can irradiate the upper surface of the substrate to be processed 105 while scanning the laser beam.
[0061]
The laser irradiation chamber 101 capable of controlling the atmosphere has a vacuum exhaust pump 108 as decompression and exhaust means. As gas supply means, a gas supply pipe 109 connected to a hydrogen cylinder through a valve and a gas supply pipe 110 connected to a cylinder of nitrogen or other gas through a valve are provided.
[0062]
The laser irradiation chamber 101 is connected to the substrate transfer chamber 302 via a gate valve 301.
[0063]
In FIG. 3, the laser irradiation chamber 101 of FIG. 1 is connected to the substrate transfer chamber 302 via a gate valve 301.
[0064]
The apparatus shown in FIG. 3 will be described. In the load / unload chamber 306, a cassette 312 in which a large number of substrates to be processed 105, for example, 20 are accommodated, is disposed. The robot arm 305 moves one substrate from the cassette 312 to the alignment chamber.
[0065]
In the alignment chamber 303, an alignment mechanism for correcting the positional relationship between the substrate to be processed 105 and the robot arm 305 is disposed. The alignment chamber 303 is connected to the load / unload chamber 306 via a gate valve 307.
[0066]
The preheating chamber 308 is for preliminarily heating the substrate to be laser annealed to a predetermined temperature, shortening the time required for heating the substrate in the laser irradiation chamber 101, and improving the throughput.
[0067]
The preheating chamber 308 is made of cylindrical quartz. Cylindrical quartz is surrounded by a heater. Furthermore, a substrate holder made of quartz is provided. The substrate holder is provided with a susceptor that can accommodate a large number of substrates. The substrate holder is moved up and down by an elevator. The substrate is heated with a heater. The preheating chamber 308 is connected to the substrate transfer chamber 302 by a gate valve 309.
[0068]
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, aligned again in the alignment chamber 303, and then transferred to the laser irradiation chamber 101 by the robot arm 305. The
[0069]
After the laser irradiation, the substrate to be processed 105 is pulled out to the substrate transfer chamber 302 by the robot arm 305 and transferred to the slow cooling chamber 310.
[0070]
The slow cooling chamber 310 is connected to the substrate transfer chamber 302 via the gate valve 311, and the substrate to be processed 105 placed on the quartz stage receives infrared light from the lamp and the reflector. Cool down gradually.
[0071]
The substrate to be processed 105 that has been gradually cooled in the slow cooling chamber 310 is transferred to the load / unload chamber 306 by the robot arm 305 and stored in the cassette 312.
[0072]
Thus, the laser annealing process is completed. In this way, by repeating the above steps, a large number of substrates can be successively processed one by one.
[0073]
A process of performing laser annealing using the apparatus shown in FIGS. 1 and 3 will be described. First, the substrate to be processed 105 (the substrate 201 having the crystalline silicon film 203) is an HF aqueous solution or HF and H ₂ O ₂ After the natural oxide film is removed by washing with the mixed aqueous solution, the cassette 312 is placed and the cassette 312 is placed in the load / unload chamber 306.
[0074]
In FIG. 3, in this embodiment, the substrate to be processed 105 transferred from the load / unload chamber 306 is aligned and then transferred to the preheating chamber 308 to prevent oxidation by air in the preheating chamber. Instead, it is directly transferred to the laser irradiation chamber 101. However, it is effective to heat the pre-heating chamber 308 to such an extent that the upper surface of the crystalline silicon film 203 is not oxidized.
[0075]
The inside of the laser irradiation chamber 101 is evacuated by the evacuation pump 108, and then oxygen is supplied from the gas supply pipe 109 and nitrogen is supplied from the gas supply pipe 110, so that the atmosphere becomes 20% oxygen and 80% nitrogen. Here, the purity of oxygen and nitrogen supplied into the laser irradiation chamber is 99.99999% (7N). At this time, the pressure is atmospheric pressure.
[0076]
The substrate 105 transferred to the laser irradiation chamber 101 is placed on the stage 111 and reaches a temperature suitable for laser annealing, here 200 ° C., by the heater in the stage 106. Heat for 5 minutes. While being heated, the upper surface of the crystalline silicon film 203 is oxidized by oxygen in the atmosphere, and a pure silicon oxide film 204 free from impurities such as carbon is formed. The film thickness is 10-50 mm, here 30 mm.
[0077]
Further, in FIG. 1, the linear laser beam irradiated onto the substrate to be processed 105 has a width of 0.34 mm and a length of 135 mm. The energy density of the laser beam on the irradiated surface is 100 mJ / cm. ² ~ 500mJ / cm ² For example, 260 mJ / cm ² And A linear laser beam is scanned by moving the stage 106 while moving it in one direction at 2.5 mm / s. When the oscillation frequency of the laser is 200 Hz and attention is paid to one point of the irradiated object, a laser beam of 10 to 50 shots is irradiated.
[0078]
In this way, the crystalline silicon film 203 is subjected to laser annealing to improve crystallinity. (Fig. 2 (B))
[0079]
Since the silicon oxide film 204 is extremely thin, most of the silicon oxide film 204 is scattered by a plurality of pulse laser irradiations.
[0080]
Thereafter, the substrate to be processed 105 is transferred to the slow cooling chamber 310, and after slow cooling, is stored in the cassette 312 in the load / unload chamber 306.
[0081]
Since the slow cooling process is an air atmosphere, the upper surface of the crystalline silicon film 203 is easily oxidized during the slow cooling process. 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 when laser irradiation is performed, the silicon oxide film 204 may not be scattered completely. 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 process is completed, the HF aqueous solution or the HF and HH are transferred to the next process. ₂ O ₂ It is preferable to reduce the silicon oxide film by reducing the upper surface of the crystalline silicon film 203 with a mixed aqueous solution of
[0082]
Next, the crystalline silicon film formed in the above process is compared with the crystalline silicon film formed in another atmosphere. In the same manner as described above, the crystalline silicon film is manufactured by changing the atmosphere during laser annealing and the energy density of the laser beam. The atmosphere is N ₂ / H ₂ (3%), N ₂ 100%. Each gas has a purity of 99.99999% (7N) or more and the atmospheric pressure is atmospheric pressure.
[0083]
FIG. 4 shows the relationship between the energy density of the laser beam and the Raman half-value half width of the laser-annealed crystalline silicon film in laser annealing in various atmospheres. The Raman half-width refers to a half value of the Raman half-width. In FIG. 4, the crystalline silicon film is an N-containing atmosphere used in the above process as an oxygen-containing atmosphere. ₂ / O ₂ (20%) ◇, N ₂ / H ₂ (3%) ○, N ₂ Those produced in a 100% atmosphere are indicated by □.
[0084]
As shown in FIG. 4, when the crystalline silicon film is laser-annealed in the oxygen-containing atmosphere of the present invention, the Raman half-width decreases as the energy density is increased, that is, the crystallinity is improved. I understand.
[0085]
However, 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. Here, the laser energy density is 270 mJ / cm. ² The following is preferred.
[0086]
On the other hand, in other atmospheres, all of the energy density in the range shown in FIG.
[0087]
The laser annealing in the oxygen-containing atmosphere may be performed not under atmospheric pressure but under a reduced pressure, particularly 0.01 Torr or more and 700 Torr or less. By performing laser annealing under such reduced pressure, the surface of the annealed crystalline silicon film or the entire film can be reduced.
[0088]
Next, a thin film transistor (TFT) is manufactured using the manufactured crystalline silicon film 203. First, the crystalline silicon film 203 is etched to form island regions 205.
[0089]
Next, a silicon oxide film to be the gate insulating film 206 is formed with a thickness of 1200 mm by plasma CVD. 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))
[0090]
Next, a gate electrode is produced. An aluminum film is deposited by sputtering to a thickness of 3000 to 8000 mm, for example 6000 mm. The aluminum film may contain 0.1 to 2% silicon. The gate electrode 207 is manufactured by etching the film.
[0091]
Next, impurities are added. In the case of manufacturing an N-channel TFT, phosphorus ions are implanted into the island region 205 by an ion doping method using the gate electrode as a mask. As doping gas, phosphine (PH _Three ) Is used. The acceleration voltage is 10 to 90 kV, for example 80 kV, and the dose is 1 × 10 ¹⁴ ~ 5x10 ¹⁵ Atom / cm ² For example, 1 × 10 ¹⁵ Atom / cm ² And The substrate temperature is room temperature. As a result, a channel formation region 210 and a source 208 and a drain 209 are formed as N-type impurity regions.
[0092]
In the case of manufacturing a P-channel TFT, boron ions are implanted into the island-shaped region 205 by ion doping using the gate electrode 207 as a mask. As a doping gas, diborane diluted with hydrogen to 1 to 10%, for example 5% (B ₂ H ₆ ) Is used. The acceleration voltage is 60 to 90 kV, for example 65 kV, and the dose is 2 × 10 ¹⁵ ~ 5x10 ¹⁵ Atom / cm ² For example, 3 × 10 ¹⁵ Atom / cm ² And The substrate temperature is room temperature. As a result, a source 208 and a drain 209 are formed as a channel formation region 210 and a P-type impurity region. (Fig. 2 (D))
[0093]
Next, in order to activate the doped impurities, laser annealing is again performed 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 ~ 350mJ / cm ² In the range of, for example, 160 mJ / cm ² And A linear laser beam is scanned. When attention is paid to one point of the irradiated object, a laser beam of 20 to 40 shots is irradiated. The substrate temperature is 200 ° C. Thereafter, thermal annealing is performed at 450 ° C. for 2 hours in a nitrogen atmosphere. (Figure 2 (E))
[0094]
Subsequently, a silicon oxide film is formed by a plasma CVD method with a thickness of 6000 mm, and an interlayer insulating film 211 is formed. Next, a contact hole is opened 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.
[0095]
Finally, a thermal annealing process at 200 to 350 ° C. is performed in a 1 atmosphere hydrogen atmosphere.
[0096]
In this way, a plurality of N or P channel type crystalline TFTs are formed. These TFTs are N-channel type, 70-120 cm ² / Vs, P-channel type 60-90cm ² It has excellent mobility with / Vs. (Fig. 2 (F))
[0097]
[Example 2]
Example 2 shows an example in which after a silicon oxide film is formed on an upper surface of a non-single-crystal silicon film in an oxygen atmosphere, laser annealing is performed in a nitrogen atmosphere. In Example 2, the laser annealing apparatus shown in FIG. 5 is used. FIG. 1 corresponds to the AA ′ cross section of the laser irradiation chamber 101 in FIG.
[0098]
In the same manner as in Example 1, a substrate to be processed 105 in which a base film 202 and a crystalline silicon film 203 crystallized by thermal annealing are formed on a substrate 201 shown in FIG. 2 is an HF aqueous solution or HF and H ₂ O ₂ After the natural oxide film is removed by washing with the mixed aqueous solution, the cassette 312 is placed and the cassette 312 is placed in the load / unload chamber 306.
[0099]
The to-be-processed substrate 105 transferred from the load / unload chamber 306 is aligned and then transferred to the preheating chamber 501.
[0100]
As shown in FIG. 5, the preheating chamber 501 has a vacuum exhaust pump 502 that depressurizes the space on which the substrate is placed, and a gas supply pipe 503 that can supply oxygen and other gases to the space on which the substrate is placed. 504 are provided.
[0101]
After the space in which the substrate is placed is evacuated by the vacuum exhaust pump 502 connected to the preheating chamber 501, oxygen is supplied from the gas supply pipe 503, nitrogen is supplied from the gas supply pipe 504, and the substrate holder Inside, an atmosphere of 5% oxygen and 95% nitrogen (both purity 99.99999 (7N)) (atmospheric pressure) is formed. Then, when preheating is performed at 50 to 300 ° C., for example, 200 ° C., the silicon oxide film 204 is simultaneously formed to 20 to 40 cm, for example, 30 mm.
[0102]
The inside of the laser irradiation chamber 101 shown in FIG. 1 is evacuated by the vacuum exhaust pump 108 and then supplied with nitrogen from the gas supply pipe 110 to become an atmosphere of 100% nitrogen (purity 99.99999% (7N)). . At this time, the pressure is atmospheric pressure.
[0103]
The substrate to be processed 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 transported substrate 105 is heated to near 200 ° C., and in the state where it is placed on the stage 111, laser annealing is performed by heating in a very short time (several minutes) by the heater in the stage 106. A suitable temperature is reached, here 200 ° C.
[0104]
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 subjected to laser annealing to improve crystallinity. (Fig. 2 (B))
[0105]
Since the silicon oxide film 204 is extremely thin, most of it is scattered by laser irradiation.
[0106]
Thereafter, the substrate to be processed 105 is transferred to the slow cooling chamber 310, and after slow cooling, is stored in the cassette 312 in the load / unload chamber 306.
[0107]
Before moving on to the next step, HF aqueous solution, HF, H ₂ O ₂ It is preferable to reduce the upper surface of the crystalline silicon film 203 with a mixed aqueous solution and remove the silicon oxide film.
[0108]
Thereafter, in the same manner as in Example 1, a thin film transistor is formed according to FIGS.
[0109]
In the case of the second embodiment, the substrate to be processed 105 is carried into the laser irradiation chamber 101 having the same or different atmosphere as the preheating chamber 501 so that the formation time of the silicon oxide film is unnecessary or the processing time is shortened. Laser annealing can be performed, and the manufacturing process can be shortened.
[0110]
In Example 2, the atmosphere in the laser irradiation chamber 101 is a nitrogen atmosphere, but a nitrogen atmosphere is used. However, other atmospheres, for example, 20% oxygen and 80% nitrogen may be used as in the first example.
[0111]
However, laser annealing in a nitrogen atmosphere has the effect of suppressing the generation of ridges (roughness of the surface of the crystalline silicon film after laser annealing) due to laser annealing compared to other air, oxygen-containing atmospheres, hydrogen-containing atmospheres, etc. There is.
[0112]
Example 3
In the third embodiment, similarly to 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 of FIG. Shows an example of laser annealing.
[0113]
Although laser annealing in air is performed, since the silicon oxide film 204 is formed, crystallinity and homogeneity are compared with the case where laser annealing is simply performed in the air without forming the silicon oxide film 204. Laser annealing with excellent properties and energy utilization efficiency can be performed.
[0114]
If the atmosphere control is not particularly performed, the laser irradiation chamber 101 which is a container capable of controlling the atmosphere may be omitted.
[0115]
Example 4
In Example 1, in the step of forming the crystalline silicon film 203 by thermal crystallization (FIG. 2A), the upper surface of the crystalline silicon film 203 is oxidized by the slow cooling step (air atmosphere) after thermal crystallization. Thus, a silicon oxide film is formed on the order of several tens of inches.
In Example 1, this silicon oxide film is removed by washing before the laser annealing step, but in Example 4, this silicon oxide film is not removed, and the laser annealing apparatus shown in FIG. Apply annealing.
[0116]
When laser annealing is performed on the crystalline silicon film 203 in a nitrogen atmosphere as in the second embodiment, compared with the case where laser annealing is performed in a nitrogen atmosphere without forming a silicon oxide film. As a result, crystallinity, homogeneity, and utilization efficiency of laser energy are greatly improved.
[0117]
Example 5
In Example 5, an example of a continuous processing apparatus used in Example 6 is shown. In this continuous processing apparatus, the cleaning process of the non-single crystal silicon film and the laser annealing process or the heating (silicon oxide film formation) process can be continuously performed without being exposed to the atmosphere.
FIG. 6 shows a top view of the continuous processing apparatus in the embodiment. The apparatus of FIG. 6 has a configuration in which a substrate cleaning chamber is added to the apparatus shown in FIG.
[0118]
In FIG. 6, a laser irradiation chamber 602, a preheating chamber 603, a slow cooling chamber 604, and a cleaning chamber 607 are connected to the substrate transfer chamber 601 through gate valves 608 to 611. In addition, a load / unload chamber 605 is connected to the substrate transfer chamber 601 via an alignment chamber 606 and a gate valve 612.
[0119]
A robot arm 613 is disposed in the substrate transfer chamber 601 as substrate transfer means for transferring the substrate 600. In the load / unload chamber 605, a cassette 615 for storing a plurality of substrates is disposed.
[0120]
In the configuration shown in FIG. 6, the substrate transfer chamber 601, the laser irradiation chamber 602, the preheating chamber 603, the slow cooling chamber 604, the load / unload chamber 605, and the alignment chamber 606 are described in FIG. Since it is the same structure as the apparatus shown in FIG.
[0121]
In the apparatus shown in FIG. 6, the airtightness between the chambers and the chambers is maintained. Each chamber is provided with gas supply means and exhaust means (not shown), and the atmosphere and pressure in each chamber can be arbitrarily controlled. Since the substrate processed by such an apparatus is shielded from the external atmosphere, it can be prevented from being exposed to the air.
[0122]
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 conveyed into the cleaning chamber 607, and rotates the substrate horizontally. The cleaning liquid outflow nozzle 618 allows the cleaning liquid to flow out to the center of the substrate rotation surface.
[0123]
As cleaning liquid, HF and H ₂ O ₂ An aqueous solution or the like in which 0.5 wt% is mixed is preferable. Alternatively, an aqueous solution of HF may be used. With this cleaning liquid, the natural oxide film, impurities, and the like on the upper surface of the non-single crystal silicon film are removed.
[0124]
The cup 617 is disposed so as to surround the periphery of the substrate when the substrate is rotated. When the substrate is transported, it is disposed below the substrate fixing position on the upper surface of the stage so as not to disturb the transport. The cup 617 receives the cleaning liquid scattered around by the rotation of the substrate and discharges it downward.
[0125]
The cleaning process by the apparatus shown in FIG. 6 will be described. After the substrate 614 is transferred into the cleaning chamber and fixed by vacuum suction on the upper surface of the stage 616, the substrate rotates at a predetermined number of rotations. At this time, the cleaning liquid flows out from the cleaning liquid outflow nozzle 618 to the center of the substrate rotation surface.
[0126]
The washed-out cleaning liquid concentrically spreads from the center of the substrate to the outside by centrifugal force, reaches the periphery of the substrate, scatters to the cup 617, and is then discharged.
[0127]
After maintaining such a state for several tens of seconds to several minutes, the outflow of the cleaning liquid is stopped, the number of rotations of the substrate is increased, and the cleaning liquid is dried.
[0128]
In this way, the cleaning process is completed. Thereafter, the substrate 604 is moved to another chamber such as a preheating chamber or a laser irradiation chamber by the transfer means 613.
[0129]
With the apparatus shown in FIG. 6, the substrate cleaning step, that is, the step of removing the natural oxide film, impurities, dust, etc. on the upper surface of the non-single crystal silicon film, and the laser annealing step in the oxygen atmosphere or the oxygen atmosphere for the non-single crystal silicon film The heating process (oxide film forming process) can be performed continuously without exposure to the atmosphere.
[0130]
As a result, a thin silicon oxide film formed on the upper surface of the non-single-crystal silicon film can be made of high quality without impurities, and good crystallization by laser annealing can be performed.
[0131]
Further, the upper surface of the crystalline silicon film can be continuously cleaned after the laser annealing step by the apparatus shown in FIG. As a result, a crystalline silicon film having a clean surface can be provided in a shorter time with respect to the step after the laser annealing step, which contributes to shortening the time required for manufacturing.
[0132]
In this embodiment, the substrate is cleaned using a cleaning liquid. In this method, since there is very little possibility that the cleaning liquid adheres to the back side of the substrate, clouding and contamination of the glass substrate by the cleaning liquid can be prevented. Furthermore, since the cleaning liquid can be dried only by rotating the substrate, the entire cleaning process can be shortened. 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 facilitate the design.
[0133]
However, the substrate cleaning method of the present embodiment is not limited to this. For example, the cleaning liquid may be allowed to flow out to the upper surface of the substrate without rotating the substrate.
[0134]
Alternatively, the non-single crystal silicon film may be exposed to a reducing gas atmosphere.
[0135]
Example 6
Example 6 shows an example in which the apparatus of FIG. 6 is used and the substrate cleaning process and the laser annealing process are continuously performed without being exposed to the atmosphere.
[0136]
A 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 on a 127 mm square Corning 1737, a silicon oxide film 202 as a base film is 2000 Å, and an amorphous silicon film is 500 Å on both, and plasma CVD is used. The film is continuously formed.
[0137]
Next, after applying the same nickel acetate aqueous solution as in Example 1, thermal annealing is performed at 600 ° C. for 4 hours to form a crystalline silicon film 203. ((FIG. 2 (A))
[0138]
Next, with the continuous processing apparatus shown in FIG. 6, the cleaning of the crystalline silicon film and the laser annealing step in an oxygen atmosphere are continuously performed.
[0139]
Each chamber of the continuous processing apparatus shown in FIG. 6 is shielded from the atmosphere, and the atmosphere is made of a clean gas from which impurities and the like have been removed by cleaning. For example, an inert gas such as nitrogen, argon, or helium, or a gas in which oxygen is mixed with these is preferable. Alternatively, purified air may be used.
[0140]
First, the substrate to be processed on which the crystalline silicon film 203 is formed is placed in the cassette 615, and the cassette 615 is placed in the load / unload chamber 606.
[0141]
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 to remove a natural oxide film or impurities on the upper surface of the crystalline silicon film 203. .
[0142]
In the cleaning chamber 607, the substrate 614 is fixed to the stage 616, and cleaning with a cleaning liquid is performed while rotating.
[0143]
The cleaning liquid for cleaning flows out from the nozzle 618 to the center portion of the substrate rotation surface. 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. Thereafter, the cleaning liquid scatters around the substrate, hits the cup 617, and is then discharged. The cleaning liquid here is HF and H ₂ O ₂ An aqueous solution in which 0.5 wt% is mixed is used. Alternatively, an HF aqueous solution may be used.
[0144]
The substrate is rotated at a rotational speed of 100 to 1000 rpm, for example, 300 rpm for 10 seconds to 5 minutes, here 1 minute, while receiving the cleaning liquid. Thereafter, the outflow of the cleaning liquid is stopped, and the substrate is rotated for about 30 seconds by increasing the number of rotations of the substrate in order to dry the upper surface of the substrate. The substrate rotation speed during drying was 2500 to 4000 rpm, here 3000 rpm.
[0145]
Thereafter, the rotation of the substrate is stopped, and the substrate is carried out of the cleaning chamber 607 by the substrate transfer means 613.
[0146]
In this manner, the upper surface of the crystalline silicon film 203 on the substrate is cleaned, and the natural oxide film and impurities are removed.
[0147]
Next, laser annealing is performed on the crystalline silicon film 203. The substrate carried out from the cleaning chamber 607 is transported directly to the laser irradiation chamber 602 or after being heated in the preheating chamber 603.
[0148]
As a result, the cleaned crystalline silicon film is transferred to the laser irradiation chamber 602 continuously with the cleaning process without being exposed to the atmosphere.
[0149]
Further, the substrate heating time in the laser irradiation chamber can be shortened by heating the preheating chamber 603 to a predetermined temperature and then transporting it to the laser irradiation chamber.
[0150]
Next, laser annealing is performed in an oxygen atmosphere. The laser irradiation chamber 602 includes an atmosphere of 20% oxygen and 80% nitrogen. Then, laser annealing is performed on the crystalline silicon film 203 in an oxygen atmosphere under the same conditions as in Example 1 to improve crystallinity. (Fig. 2 (B))
[0151]
In the present embodiment, the substrate to be processed is not exposed to the atmosphere at all from the previous cleaning process to the laser annealing process by using the continuous processing apparatus of FIG. Therefore, a natural oxide film formed in the atmosphere and impurities in the atmosphere are substantially removed in the thin silicon oxide film 204 formed on the upper surface of the crystalline silicon film 203 in the laser annealing step and in the vicinity thereof. As a result, the silicon oxide film 204 becomes an extremely pure silicon oxide film, and laser annealing can be performed more effectively than in the first embodiment.
[0152]
That is, the thickness and quality of the thin silicon oxide film 204 to be formed are more uniform on the upper surface of the crystalline silicon film 203 than in the case of the first embodiment, and as a result, the film crystallized by laser annealing. The film quality uniformity in the substrate plane is improved.
[0153]
Furthermore, the penetration of impurities into the crystalline silicon film 203 during laser annealing is further reduced. As a result, various characteristics such as mobility and threshold value of the manufactured thin film transistor can be more stabilized both in the substrate surface and between lots.
[0154]
After completion of the laser annealing step, the substrate is transferred to the annealing chamber 604 and gradually cooled as necessary.
[0155]
Thereafter, the substrate may be transferred to the load / unload chamber, but the silicon oxide film tends to remain on the upper surface of the crystalline silicon film 203 after the laser annealing step.
[0156]
That is, 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 when laser irradiation is performed, the entire silicon oxide film 204 may not be scattered.
[0157]
Therefore, it is very effective to transport the substrate again to the cleaning chamber after the laser annealing step and perform cleaning.
[0158]
As a process, the substrate is unloaded from the laser irradiation chamber 602 or the slow cooling chamber 604 and then loaded into the cleaning chamber 607 to clean the upper surface of the crystalline silicon film 203 and remove the silicon oxide film, impurities, and the like. The conditions are the same as in the cleaning step before the laser annealing step.
[0159]
As described above, the laser annealing step and the cleaning step, or the slow cooling step and the cleaning step are continuously performed without being exposed to the atmosphere, whereby high cleanliness of the upper surface of the crystalline silicon film can be obtained in a short time.
[0160]
After that, the substrate after the cleaning process is transferred from the cleaning chamber 607 to the load / unload chamber 606 by the substrate transfer means 613 and stored in the cassette 615.
[0161]
Thereafter, the thin film transistor is completed by the same process as in the first embodiment. (FIG. 2C to FIG. 2F)
[0162]
The thin film transistor thus manufactured has improved characteristics and has stable characteristics within the substrate surface and between lots.
[0163]
Example 7
In Example 7, an example is shown in which the continuous processing apparatus of FIG. 6 is used, and after forming a silicon oxide film on the upper surface of the non-single crystal silicon film in an oxygen atmosphere, laser annealing is performed in a nitrogen atmosphere.
[0164]
A thin film transistor is manufactured according to FIG. A silicon oxide film 202 and an amorphous silicon film as a base film are continuously formed on the substrate 201, and after applying a nickel acetate aqueous solution, thermal annealing is performed at 600 ° C. for 4 hours to obtain a crystalline silicon film. 203 is formed. ((FIG. 2 (A))
[0165]
Next, the upper surface of the crystalline silicon film 203 is cleaned in the cleaning chamber 607 using the continuous processing apparatus shown in FIG. Thereby, the natural oxide film and impurities on the upper surface of the crystalline silicon film 203 are removed.
[0166]
Next, the substrate is transferred to the preheating chamber 603. In the preheating chamber 603, an atmosphere of 5% oxygen and 95% nitrogen (both purity 99.99999 (7N)) (atmospheric pressure) is formed. Then, when preheating is performed at 50 to 300 ° C., for example, 200 ° C., a thin silicon oxide film 204 is formed on the upper surface of the crystalline silicon film 203 in a thickness of 20 to 40, for example, 30%.
[0167]
The silicon oxide film 204 formed here is an extremely pure film in which the upper surface of the crystalline silicon film 203 is cleaned by the previous cleaning process and is not exposed to the air, so that impurities are not mixed therein.
[0168]
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.
[0169]
Then, laser annealing is performed under the same conditions as in Example 6 except for the atmosphere, and the crystallinity of the crystalline silicon film 203 is improved. (Fig. 2 (B))
[0170]
The crystalline silicon film 203 after laser annealing improves the uniformity of crystallization by laser annealing in the substrate surface as compared with that obtained in Example 2. Further, various characteristics such as mobility and threshold of the thin film transistor to be manufactured are more stable both within the substrate surface and between lots.
[0171]
In addition, since the atmosphere during laser annealing is a nitrogen atmosphere, generation of ridges can be suppressed as compared with an 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, ridges are suppressed, and the crystalline silicon film The film quality can be further improved.
[0172]
Thereafter, in the same manner as in Example 6, a thin film transistor is formed according to FIGS.
[0173]
In the process of the present embodiment, the time required for forming the silicon oxide film 204 in the laser irradiation chamber is unnecessary as in the second embodiment. Accordingly, the manufacturing process time can be shortened.
[0174]
In this embodiment, even if the atmosphere during laser annealing is other than a nitrogen atmosphere, it can be implemented as long as it is a clean atmosphere.
[0175]
【The invention's effect】
According to the present invention, crystallinity and homogeneity can be significantly improved and 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 embodiment.
FIG. 2 is a diagram showing a manufacturing process of the example.
FIG. 3 is a top view of the laser annealing apparatus in the embodiment.
FIG. 4 is a diagram showing the relationship between the energy density of a laser beam and the Raman half-value half width of a laser-annealed crystalline silicon film in laser annealing in various atmospheres.
FIG. 5 is a top view of the laser annealing apparatus in the embodiment.
FIG. 6 is a top view of the continuous processing apparatus in the embodiment.
[Explanation of symbols]
101 Laser irradiation room
102 Laser oscillator
103 mirror
104 windows
105 Substrate
106 units
107 Movement mechanism
108 Vacuum pump
109, 110 Gas supply pipe
111 stages
112 Optical system
201 substrate
202 Silicon oxide film (underlying film)
203 Crystallized silicon film
204 Silicon oxide film
205 island area
206 Gate insulation film
207 Gate electrode
208 sources
209 drain
210 Channel formation region
211 Interlayer insulation film
212 Source electrode / wiring
213 Drain electrode / wiring
301 Gate valve
302 Substrate transfer chamber
303 alignment room
305 Robot arm
306 Load / unload room
307 Gate valve
308 Preheating chamber
309 Gate valve
310 Slow cooling room
311 Gate valve
312 cassette
501 Preheating chamber
502 vacuum pump
503, 504 Gas supply pipe
601 Substrate transfer chamber
602 Laser irradiation room
603 Preheating chamber
604 Slow cooling room
605 Load / unload room
606 Alignment room
607 Washing room
608-612
613 Robot arm
614 substrate
615 cassette
616 stage
617 cups
618 nozzle

Claims (20)

The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
A laser annealing method for performing a laser annealing treatment in an atmosphere containing oxygen on the non-single crystal silicon film,
The laser annealing method, wherein the cleaning treatment and the laser annealing treatment are continuously performed without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
A laser annealing method for performing a laser annealing treatment in an atmosphere containing oxygen on the non-single crystal silicon film,
The laser annealing method, wherein the removal of the natural oxide film and the laser annealing treatment are continuously performed without exposure to the atmosphere. The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing method for performing a laser annealing treatment in an atmosphere containing only oxygen in the non-single-crystal silicon film through the silicon oxide film, or a mixed gas of oxygen and an inert gas,
The laser annealing method, wherein the cleaning process, the formation of the silicon oxide film, and the laser annealing process are performed continuously without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing method for performing a laser annealing treatment in an atmosphere containing only oxygen in the non-single-crystal silicon film through the silicon oxide film, or a mixed gas of oxygen and an inert gas,
The laser annealing method, wherein the removal of the natural oxide film, the formation of the silicon oxide film, and the laser annealing treatment are continuously performed without exposure to the atmosphere. In any one of Claims 1 thru | or 4,
The laser annealing method, wherein the laser annealing treatment is performed under a reduced pressure of 0.01 Torr to 700 Torr. In claim 1 or claim 2,
The laser annealing process is performed in an atmosphere containing only oxygen or in a mixed gas of oxygen and inert gas. In claim 3, claim 4, or claim 6,
The laser annealing method according to claim 1, wherein oxygen in the mixed gas is contained at 1% or more under atmospheric pressure. In claim 6 or claim 7,
Both the purity of the oxygen and the purity of the inert gas are 99.9% or more and 99.99999% or less. The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing method for performing a laser annealing treatment in a nitrogen atmosphere on the non-single-crystal silicon film through the silicon oxide film,
The laser annealing method, wherein the cleaning process, the formation of the silicon oxide film, and the laser annealing process are performed continuously without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing method for performing a laser annealing treatment in a nitrogen atmosphere on the non-single-crystal silicon film through the silicon oxide film,
The laser annealing method, wherein the removal of the natural oxide film, the formation of the silicon oxide film, and the laser annealing treatment are continuously performed without exposure to the atmosphere. The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
A laser annealing treatment is performed in an atmosphere containing oxygen on the non-single crystal silicon film to form a crystalline silicon film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the cleaning treatment and the laser annealing treatment are continuously performed without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
A laser annealing treatment is performed in an atmosphere containing oxygen on the non-single crystal silicon film to form a crystalline silicon film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the removal of the natural oxide film and the laser annealing treatment are continuously performed without exposure to the atmosphere. The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A crystalline silicon film is formed by performing laser annealing in an atmosphere containing only oxygen in the non-single-crystal silicon film or a mixed gas of oxygen and an inert gas through the silicon oxide film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the cleaning treatment, the formation of the silicon oxide film, and the laser annealing treatment are performed continuously without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A crystalline silicon film is formed by performing laser annealing in an atmosphere containing only oxygen in the non-single-crystal silicon film or a mixed gas of oxygen and an inert gas through the silicon oxide film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the removal of the natural oxide film, the formation of the silicon oxide film, and the laser annealing treatment are continuously performed without exposure to the atmosphere. In any one of Claims 11 thru | or 14,
The method for manufacturing a thin film transistor, wherein the laser annealing treatment is performed under a reduced pressure of 0.01 Torr to 700 Torr. In claim 11 or claim 12,
The method of manufacturing a thin film transistor, wherein the laser annealing treatment is performed in an atmosphere containing only oxygen or a mixed gas of oxygen and an inert gas. In claim 13, claim 14, or claim 16,
A method for manufacturing a thin film transistor, wherein oxygen in the mixed gas is contained at 1% or more under atmospheric pressure. In claim 16 or claim 17,
The method for manufacturing a thin film transistor, wherein the purity of the oxygen and the purity of the inert gas are both 99.9% or more and 99.99999% or less. The non-single crystal silicon film formed on the substrate is cleaned using an HF aqueous solution or a mixed aqueous solution of HF and H ₂ O ₂ ,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing treatment is performed in a nitrogen atmosphere on the non-single crystal silicon film through the silicon oxide film to form a crystalline silicon film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the cleaning treatment, the formation of the silicon oxide film, and the laser annealing treatment are performed continuously without being exposed to the atmosphere. The natural oxide film on the non-single crystal silicon film formed on the substrate is removed by a cleaning process,
Forming a silicon oxide film having a thickness of 0.5 to 10 nm on the non-single-crystal silicon film;
A laser annealing treatment is performed in a nitrogen atmosphere on the non-single crystal silicon film through the silicon oxide film to form a crystalline silicon film,
Forming a gate insulating film on the crystalline silicon film;
A thin film transistor manufacturing method for forming a gate electrode on the gate insulating film,
The method for manufacturing a thin film transistor, wherein the removal of the natural oxide film, the formation of the silicon oxide film, and the laser annealing treatment are continuously performed without exposure to the atmosphere.

Images