JP3926862B2 - Semiconductor processing method and thin film transistor manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention disclosed in the present specification relates to a technique (generally referred to as a laser process) for performing various annealing and surface alteration by laser light irradiation. In particular, the present invention relates to an annealing technique for semiconductor materials by laser light irradiation. For example, the present invention relates to a technique for transforming an amorphous silicon film into a crystalline silicon film by laser light irradiation.
[0002]
[Prior art]
Conventionally, a technique for crystallizing a semiconductor film, for example, an amorphous silicon film by laser light irradiation is known. Also known is a technique of irradiating a laser beam after implanting impurity ions into a silicon film to repair a crystal structure damaged by the implantation of impurity ions or activating the implanted impurities.
[0003]
The annealing technique by laser light irradiation does not heat the entire sample to a high temperature, and a high annealing effect can be obtained. Accordingly, in recent years, it has been used in a thin film transistor manufacturing process on a glass substrate, which is required for manufacturing an active matrix LCD device.
[0004]
When a thin film transistor is manufactured over a glass substrate, it is necessary to perform annealing within a temperature range that the glass substrate can withstand. In the annealing process by laser irradiation, anilil is performed by instantaneously melting the surface of the irradiated surface, and the substrate can be hardly damaged by heat.
[0005]
Therefore, this is one of the most suitable annealing techniques when glass is used as the substrate.
[0006]
Further, as a significant point of the laser process, there is a feature that the process time is short.
[0007]
For example, when an amorphous silicon film formed on each 10 cm glass substrate is crystallized by heating, it is required to be at a temperature of 600 ° C. for 12 to 24 hours or more. (In this case, there is a problem of thermal damage to the glass substrate, but it is ignored here.)
[0008]
However, in the method using laser light irradiation, an amorphous silicon film can be transformed into a crystalline silicon film within a few minutes.
[0009]
[Problems to be solved by the invention]
As described above, the annealing technique by laser light irradiation is useful in the sense that the process can be performed at a low temperature. However, according to studies by the present inventors, it has been found that sufficient annealing effect and reproducibility cannot be obtained unless a certain amount of heating is used in combination.
[0010]
The heating temperature required for the laser light irradiation is not as high as 800 ° C. to 900 ° C. or higher, which is required in the manufacturing process of a semiconductor device using a normal silicon semiconductor, but 100 to 500 ° C. It has been found that the degree is sufficient.
[0011]
In general, a glass substrate can sufficiently withstand up to about 600 ° C., so that the heating is not particularly problematic.
[0012]
The problem here is that it takes several hundred seconds or more (several minutes or more) to heat the sample (substrate) to a predetermined temperature and stabilize it at a certain temperature, whether it is 200 ° C. or 300 ° C. Is that time is needed.
[0013]
As described above, the process time by laser light irradiation is several minutes. Therefore, the heating time is as long as that or longer.
[0014]
Considering the premise of mass production, shortening the process time in minutes in the laser process means increasing productivity at a rate of several tens of percent.
[0015]
Therefore, shortening the heating time in the above laser process is an industrially important matter.
[0016]
An object of the invention disclosed in this specification is to provide a technique capable of shortening a laser processing step including a heating time in a laser process.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, the configuration of the present invention is as follows.
After the semiconductor film is arranged and heated in a helium atmosphere, the surface of the semiconductor film is irradiated with laser light.
[0018]
As the helium atmosphere, helium, helium and hydrogen, helium and oxygen, helium, hydrogen, oxygen mixed gas, or a plasma state thereof can be used.
[0019]
Alternatively, after the semiconductor film is heated in a helium atmosphere, the surface of the semiconductor film may be irradiated with laser in another atmosphere such as nitrogen.
[0020]
Other configurations of the present invention include:
The semiconductor film placed in a helium atmosphere containing hydrogen is irradiated with laser light on the surface of the semiconductor film while being heated to a predetermined temperature.
[0021]
In particular, it is preferable that the atmosphere containing hydrogen is in a plasma state. Further, oxygen may be contained in the helium atmosphere.
[0022]
Other configurations of the present invention include:
After the surface of the semiconductor film is treated in an oxidizing atmosphere, the semiconductor film is laser annealed in a helium atmosphere.
[0023]
In particular, it is preferable to contain hydrogen in a helium atmosphere. Moreover, it is preferable to make the helium atmosphere containing hydrogen into a plasma state.
[0024]
As the laser light in the invention disclosed in this specification, a continuous wave laser, a pulse laser, or the like can be used. It is particularly preferable to use a pulsed laser. In addition, it is extremely preferable to use a pulsed laser such as an excimer laser for the semiconductor film, particularly for a non-single crystal silicon film.
[0025]
The oxidizing atmosphere can be composed of oxygen, ozone, a mixed gas thereof, or oxygen plasma.
[0026]
As a means for generating plasma, it is preferable to use a method by supplying electromagnetic energy (generally, high frequency energy).
[0027]
[Action]
By raising the temperature of the substrate by setting the atmosphere to be a helium atmosphere or a mixed atmosphere of hydrogen and helium, the heating time until the temperature of the substrate, that is, the temperature of the silicon film that is the irradiated surface is stabilized can be greatly shortened. This is due to the fact that the thermal conductivity of hydrogen or helium is 6 to 7 times higher than that of nitrogen or oxygen.
[0028]
As a result, the time required for the laser process can be greatly reduced.
[0029]
In addition, in the annealing process for the silicon film, by adding oxygen to the atmosphere, annealing can be performed while forming an oxide film functioning as a protective film on the surface of the silicon film when irradiated with laser light. Can be prevented.
[0030]
Further, by annealing the silicon film in the oxygen-containing atmosphere, organic substances present on the surface of the semiconductor film can be decomposed and removed by the action of oxygen, and the film quality of the silicon film obtained after annealing can be improved. it can.
[0031]
This is because the oxygen in the atmosphere is activated or ozonized by the energy of the laser light near the surface of the silicon film irradiated with the laser light, and the surface of the silicon film is activated by the activated oxygen molecules, oxygen atoms or ozone. This is because the organic substances present in the are decomposed and removed.
[0032]
In addition, by applying electromagnetic energy such as high frequency to a plasma state in an atmosphere containing helium containing oxygen and / or hydrogen, the action of hydrogen plasma or oxygen plasma can be promoted by helium plasma.
[0033]
In particular, by performing laser annealing in a hydrogen plasma in a heated state of 300 to 600 ° C., more preferably 300 to 350 ° C., the surface of the silicon film and defects existing in the film and compensation of dangling bonds are performed. Can do. That is, since the hydrogen heat treatment can be performed simultaneously with the laser annealing, the laser process can be further shortened. In addition, the organic substance is decomposed and removed.
[0034]
In addition, with the use of oxygen plasma, decomposition and removal of organic substances and formation of an oxide film, which are the effects in the oxygen atmosphere described above, can be performed more efficiently and in a short time.
[0035]
In addition, when plasma is generated by containing helium with oxygen or hydrogen, the activity of oxygen or hydrogen is promoted by helium in a plasma state having a long lifetime, and the action of the oxygen plasma or hydrogen plasma is further increased.
[0036]
【Example】
[Example 1]
In this embodiment, an example is shown in which a glass substrate is carried into an apparatus that is actually irradiated with laser light, and then the time during which the substrate is heated to a predetermined temperature is measured.
[0037]
FIG. 1 shows the relationship between the elapsed time after the substrate is loaded into the apparatus and the substrate temperature. FIG. 2 shows the configuration of the laser irradiation apparatus used to obtain the data shown in FIG. Details of the apparatus shown in FIG.
[0038]
The data shown in FIG. 1 shows that the atmosphere is nitrogen (N ₂ The difference in the heating time of the substrate when the 100% atmosphere and the helium (He) 100% atmosphere are used. In collecting data, the heating conditions of the substrate and the type of the substrate were the same, and there was no difference in conditions other than the atmosphere. The experiment was conducted under atmospheric pressure.
[0039]
As is apparent from FIG. 1, when helium is used as the atmosphere, it takes about 600 seconds to stabilize at a predetermined temperature (165 ° C. here). On the other hand, when nitrogen is used as the atmosphere, it takes about 1000 seconds to reach a predetermined temperature.
[0040]
That is, the heating time can be shortened by about 40% in the helium atmosphere than in the nitrogen atmosphere.
[0041]
The thermal conductivities of nitrogen and oxygen are 260 (10 ^-Four Wm ^-1 K ^-1 ) And 267 (10 ^-Four Wm ^-1 K ^-1 Therefore, it can be assumed that the air atmosphere is almost the same as the nitrogen atmosphere. Therefore, it is estimated that the same result as the data shown in FIG. 1 can be obtained even when the atmosphere is air instead of the nitrogen atmosphere.
[0042]
Note that the thermal conductivity of helium is 1499 (10 ^-Four Wm ^-1 K ^-1 ) As a substrate having a higher thermal conductivity than that of hydrogen (the thermal conductivity is 1815 (10 ^-Four Wm ^-1 K ^-1 )). However, it is dangerous to mix 3% or more of hydrogen even in an inert atmosphere due to the explosion limit, and it is difficult to obtain an action related to the thermal conductivity. (At this point helium is very safe)
[0043]
The data shown in FIG. 1 is for normal pressure, but the tendency is further promoted when a reduced pressure atmosphere is used. That is, the effect of using helium is higher in a reduced pressure atmosphere.
[0044]
In FIG. 1, the close contact with the heater indicates a state where the substrate is disposed on the stage having the heater.
[0045]
[Example 2]
In the second embodiment, details of the laser irradiation chamber used for obtaining the data shown in the first embodiment will be described.
[0046]
FIG. 2 shows an outline of a cross section of the laser irradiation apparatus. A top view thereof is shown in FIG. In FIG. 2, 101 is a laser irradiation chamber. The laser irradiation chamber 101 is shielded from the outside and can be kept in a reduced pressure state.
[0047]
The laser light is oscillated by the laser irradiation device 102 and the cross-sectional shape is processed into a linear shape by the optical system 112. Then, the light is reflected by the mirror 103 and irradiated onto the substrate 401 to be processed through the window 104 made of quartz.
[0048]
As the laser oscillation device 102, a device that oscillates a XeCl excimer laser (wavelength 308 nm) is used. In addition, a KrF excimer laser (wavelength 248 nm) can be used.
[0049]
The substrate 401 to be processed is placed on a stage 111 provided on a table 106 and is maintained at a predetermined temperature (room temperature to 700 ° C., preferably 100 to 500 ° C.) by a heater installed in the table 106. .
[0050]
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 401 to be processed while scanning the laser beam.
[0051]
The laser irradiation chamber 101 is provided with a vacuum exhaust pump 108, and the inside can be reduced or vacuumed as necessary.
[0052]
The laser irradiation chamber 101 has a gas supply unit 109. The gas supply unit 109 is connected to a gas cylinder (not shown) and supplies helium gas into the laser irradiation chamber.
[0053]
If necessary, another gas supply unit 110 for introducing oxygen or other inert gas may be provided.
[0054]
The laser irradiation chamber 101 has a gate valve 501 and can be connected to other processing chambers. Further, the substrate (sample) can be taken in and out through the gate valve 501 as necessary.
[0055]
2 and 3 can irradiate the non-single-crystal semiconductor film over the substrate 401 with laser light in an atmosphere containing ozone or a reduced-pressure atmosphere thereof.
[0056]
With such a configuration, heating in a helium atmosphere can be performed, and the time from the start of heating a sample until the sample is stabilized at a predetermined temperature is reduced to about 60% as compared with an air or nitrogen atmosphere.
[0057]
Example 3
This embodiment shows an example in which a thin film transistor is formed over a glass substrate using the laser irradiation apparatus shown in Embodiment 2.
[0058]
FIG. 4 shows a manufacturing process of the example. First, a 127 mm square Corning 1737 glass substrate is prepared as the substrate 401 to be processed.
[0059]
Then, a silicon oxide film 402 as a base film is formed on the substrate 401 to a thickness of 2000 mm. As a film forming method, a plasma CVD method is used. Next, an amorphous silicon film (not shown) is formed to a thickness of 500 mm by plasma CVD.
[0060]
Next, an aqueous nickel acetate solution of about 10 ppm is applied onto the amorphous silicon film by spin coating so that the nickel element is held in contact with the surface of the amorphous silicon film. Details of the crystallization technique using nickel are described in JP-A-6-244104.
[0061]
In this state, heat treatment at 600 ° C. for 4 hours is performed in a hydrogen-containing atmosphere (that is, a reducing atmosphere). By this heat treatment, the amorphous silicon film is crystallized and transformed into a crystalline silicon film 303 (FIG. 4A).
[0062]
The concentration of nickel element finally remaining in the film is 1 × 10 ¹⁵ ~ 5x10 ¹⁹ Atom / cm ^Three It is desirable to be within the range.
[0063]
In this way, a crystalline silicon film 403 is obtained. Next, in order to further improve the crystallinity of the obtained crystalline silicon film 403, laser annealing is performed using an excimer laser.
[0064]
Laser annealing is performed using the apparatus shown in FIG. In performing laser annealing, a helium atmosphere is used, and processing is performed under atmospheric pressure. It is good also as atmospheric pressure or less, for example, 0.02-0.5 Torr.
[0065]
As the helium atmosphere, in addition to 100% helium, oxygen (preferably having a purity as high as possible), hydrogen, ozone, or a mixed gas with other inert gas may be used. Further, at least two of oxygen, hydrogen, and ozone may be mixed with helium.
[0066]
Here, the atmosphere is 80% helium and 20% oxygen.
[0067]
Here, the substrate to be processed 401 is heated to a temperature of 100 ° C. to 600 ° C., for example, 350 ° C. The time required to reach 350 ° C. after placing the substrate 401 to be processed on the stage was about 1000 seconds.
[0068]
In this state, an extremely thin silicon oxide film 404 is formed on the surface of the crystalline silicon film 403 by oxygen. The thickness of the silicon oxide film 404 is about 10 to 100 mm. This silicon oxide film 404 is an extremely high quality film in which impurities are hardly mixed.
[0069]
In this state, laser light irradiation is performed. The irradiated linear laser beam has a size of 0.34 mm width × 135 mm length on the irradiation surface. Energy density is 100mJ / cm ² ~ 500mJ / cm ² For example, 260 mJ / cm ² And
[0070]
This laser light irradiation is performed while moving the table 106 of FIG. 2 in one direction at 2.5 mm / s. By doing so, it is possible to irradiate the irradiated surface while scanning the linear laser beam.
[0071]
The oscillation frequency of the laser is 200 Hz. When laser light irradiation is performed under the above conditions, 10 to 50 shots of laser light are irradiated at one point on the irradiated surface.
[0072]
In the above process, oxygen is ozonized or activated by laser light, and organic substances adhering to the surface of the crystalline silicon film can be removed as volatile oxides by the action of ozone or active oxygen. .
[0073]
Further, since the silicon oxide film 404 is extremely thin, most of the silicon oxide film 404 is scattered by a plurality of pulse laser irradiations. After scattering, a very thin silicon oxide film may be formed by oxygen in the atmosphere.
[0074]
When the silicon oxide film 404 is formed, an organic substance remaining on the surface of the silicon film is taken into the film. Therefore, when the silicon oxide film is scattered by the laser light irradiation, the organic substance can be prevented from being taken into the silicon film.
[0075]
In addition, the ultra-thin oxide film formed by the action of oxygen after laser light irradiation also prevents the formation of irregularities on the surface of the film due to hydrogen erupting from the inside of the film during laser light irradiation. Have.
[0076]
After the laser annealing is finished, the silicon oxide film tends to remain or be formed on the upper surface of the crystalline silicon film 403. Therefore, before moving to the next step, HF aqueous solution and HF and H ₂ O ₂ It is preferable to reduce the upper surface of the crystalline silicon film 403 with the mixed aqueous solution and remove the silicon oxide film.
[0077]
In this way, the crystalline silicon film 403 is subjected to laser annealing in the helium atmosphere 420 to improve its crystallinity. (Fig. 4 (B))
[0078]
The produced crystalline silicon film 403 can be excellent in crystallinity, film quality homogeneity, and electrical characteristics such as mobility.
[0079]
Next, a thin film transistor (TFT) is manufactured using the crystalline silicon film 403 whose crystallinity is promoted by laser annealing. First, the crystalline silicon film 403 is etched to form island regions 405. This island region 405 will later constitute the active layer of the thin film transistor.
[0080]
Next, a silicon oxide film to be the gate insulating film 406 is formed to a thickness of 1200 mm by plasma CVD. Here, TEOS and oxygen are used as source gases for forming this silicon oxide film.
[0081]
Next, a gate electrode is produced. Here, an aluminum film (not shown) is first formed to a thickness of 6000 mm by sputtering. The aluminum film contains scandium or silicon in an amount of 0.1 to 2% by weight. Then, this aluminum film is etched to form a gate electrode 407. (Fig. 4 (C))
[0082]
Next, impurity ions are implanted to form source / drain regions. Here, in order to fabricate an N-channel TFT, P (phosphorus) ions are implanted by an ion doping method.
[0083]
This phosphorus ion implantation is performed using the gate electrode 407 as a mask. The doping condition is phosphine (PH _Three ), The acceleration voltage is 80 kV, and the dose is 1 × 10 ¹⁵ Atom / cm ² Do as. The substrate temperature is room temperature.
[0084]
In this doping step, a channel formation region 410, a source region 408 that is an N-type impurity region, and a drain region 409 are formed in a self-aligned manner. (Fig. 4 (D))
[0085]
Next, in order to activate the doped impurities, laser annealing is again performed with linear laser light using the laser annealing apparatus shown in FIG. Here, laser annealing is performed in a helium / oxygen atmosphere under the above-described conditions.
[0086]
The energy density of laser light on the irradiated surface is 100 mJ / cm. ² ~ 350mJ / cm ² Perform in the range. Here, 160mJ / cm ² And
[0087]
As described above, irradiation is performed while scanning with a linear laser beam. In this way, a laser beam of 20 to 40 shots is irradiated at one point of the irradiated object.
[0088]
By this laser annealing, the impurities are activated and the damage during the previous implantation of impurity ions is annealed. After the laser annealing, thermal annealing is performed at 450 ° C. for 2 hours in a nitrogen atmosphere. (Fig. 4 (E))
[0089]
Next, a silicon oxide film is formed as an interlayer insulating film 411 to a thickness of 6000 mm by plasma CVD.
[0090]
Further, contact holes are formed in the interlayer insulating film 411, and a source electrode 412 and a drain electrode 413 are formed with a metal material, for example, a multilayer film of titanium and aluminum.
[0091]
Finally, thermal annealing is performed at 200 to 350 ° C. in a hydrogen atmosphere at 1 atm to complete the thin film transistor shown in FIG.
[0092]
In this way, a plurality of N and / 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 can be excellent with a mobility of / Vs.
[0093]
[Comparative Example]
Here, an example in which the atmosphere at the time of laser annealing shown in Example 3 is composed of a gas other than helium is shown.
[0094]
here,
(A) Air
(B) Oxygen: nitrogen = 20%: 80%
(C) Nitrogen 100%
An example in which laser light irradiation is performed in the three types of atmospheres shown in FIG. The atmosphere is atmospheric pressure, and the conditions other than the atmosphere are the same as in Example 3.
[0095]
In each atmosphere, the time required for the substrate 401 to reach the predetermined temperature, 350 ° C., and stabilize after being placed on the stage of the laser irradiation chamber is about 1600 seconds. It was.
[0096]
Further, the crystalline silicon film produced in the air atmosphere has a slightly lower crystallinity than that formed in the helium / oxygen atmosphere shown in Example 3. There is also a tendency for the crystallinity to be non-uniform. Further, the mobility is low, and the mobility variation is large in the film plane. Further, when a plurality of substrates are processed, there is a large variation in film characteristics between the substrates.
[0097]
These causes seem to be because organic substances on the substrate surface are not sufficiently removed, and impurities in the air are mixed into the film.
[0098]
The crystalline silicon film obtained in an oxygen: nitrogen = 20%: 80% atmosphere has improved mobility compared to the air atmosphere, and is almost equivalent to the helium: oxygen = 20%: 80% in Example 3. Characteristics are obtained. However, as described above, the substrate heating time is longer in the oxygen / nitrogen atmosphere.
[0099]
In the 100% nitrogen atmosphere, the crystallinity of the entire film is low. In addition, the in-plane uniformity of mobility and film quality will be low.
[0100]
In addition, a crystalline silicon film formed in a helium atmosphere containing nitrogen or a nitrogen atmosphere can have higher crystallinity at the same energy density as compared with those formed in other atmospheres.
[0101]
Example 4
Example 4 shows a configuration in which the laser irradiation apparatus shown in Example 2 is developed into a multi-chamber apparatus.
[0102]
FIG. 5 shows a top view of the laser annealing apparatus in the present embodiment. Here, a multi-chamber laser annealing apparatus shown in FIG. 5 is used. The figure which shows the AA 'cross section in FIG. 5 corresponds to FIG.
[0103]
The apparatus shown in FIG. 5 has a configuration in which a load / unload chamber 506, a laser irradiation chamber 101, a preheating chamber 508, and a slow cooling chamber 510 are connected via a substrate transfer chamber 502.
[0104]
Each chamber is airtight and can be set to the required atmosphere and pressure. Each chamber is connected to the substrate transfer chamber 502 by gate valves 501, 511, 509 and 507.
[0105]
In the apparatus shown in FIG. 5, reference numeral 506 denotes a load / unload chamber, which is a chamber in which a substrate (sample) to be processed is taken in and out. Substrates to be processed are loaded into the loading / unloading chamber 506 for each cassette in which a large number (for example, 20) is stored.
[0106]
The substrates loaded for each cassette are transferred to the alignment chamber 503 one by one by a robot arm 505 disposed in the substrate transfer chamber 502.
[0107]
An alignment mechanism for correcting the positional relationship between the substrate to be processed 504 and the robot arm 505 is disposed in the alignment chamber 503. The alignment chamber 503 is connected to the load / unload chamber 506 via a gate valve 507.
[0108]
The substrate 504 whose position has been adjusted in the alignment chamber 503 is transferred to the preheating chamber 508 by the robot arm 505. After the transfer, the gate valve 509 is closed to maintain airtightness. It is desirable that all the chambers have the same pressure during the operation of the apparatus so that pressure adjustment is not required when transferring the substrate between the chambers.
[0109]
In the preheating chamber 508, the substrate to be laser annealed is preliminarily heated to a predetermined temperature. This is to reduce the time required for substrate heating in the laser irradiation chamber 101 and to improve the throughput.
[0110]
Further, it is also for preliminarily heating to release hydrogen in the film and enhancing the effect of laser light irradiation. This effect of releasing hydrogen becomes remarkable when an amorphous silicon film is used as the film to be annealed.
[0111]
The preheating chamber 508 is made of cylindrical quartz. Cylindrical quartz is surrounded by a heater so that the inside can be heated.
[0112]
The preheating chamber 508 includes a substrate holder made of quartz. 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 preheating chamber 508 and the substrate transfer chamber 502 are connected by a gate valve 509.
[0113]
In addition, it is extremely effective to preheat the substrate by providing a gas supply unit and an exhaust vacuum pump in the preheating chamber 508 so that the substrate holder has a helium atmosphere.
[0114]
By performing preheating in a helium atmosphere,
(1) The preheating time is shorter than the air atmosphere.
(2) The formation of an oxide film on the upper surface of the silicon film in an air atmosphere is prevented, and impurities in the air are not mixed in the film.
The effect is obtained.
[0115]
In the preheating chamber 508, the substrate preheated for a predetermined time is pulled back to the substrate transfer chamber 502 by the robot arm 505, and alignment adjustment is performed again in the alignment chamber 503. Then, it is transferred to the laser irradiation chamber 101 by the robot arm 505.
[0116]
After the laser irradiation is completed, the substrate to be processed 504 is pulled out to the substrate transfer chamber 502 by the robot arm 505 and transferred to the slow cooling chamber 510.
[0117]
The annealing chamber 510 is connected to the substrate transfer chamber 502 via the gate valve 511, and the substrate to be processed placed on the quartz stage is exposed to infrared light from the lamp and the reflection plate. It is gradually cooled.
[0118]
The substrate to be processed that has been gradually cooled in the slow cooling chamber 510 is transferred to the load / unload chamber 506 by the robot arm 505 and stored in the cassette 512.
[0119]
Thus, the laser annealing process is performed on one substrate. In this way, by repeating the above process, a number of substrates are processed one by one continuously.
[0120]
In the laser annealing apparatus shown in FIG. 5, it is effective to supply helium gas not only to the laser irradiation chamber and the preheating chamber, but also to the load / unload chamber, the substrate transfer chamber, and the slow cooling chamber to form a helium atmosphere. is there. If it does in this way, a to-be-processed substrate will not touch air, and it can prevent that the impurity in air mixes in a silicon film.
[0121]
Example 5
This embodiment relates to a configuration in which a crystalline silicon film is obtained by performing laser annealing on an amorphous silicon film. In the present embodiment as well, the laser irradiation apparatus shown in FIG.
[0122]
First, a 127 mm square and 1.1 mm thick Corning 1737 substrate is prepared as a substrate. A silicon oxide film having a thickness of 2000 mm is formed on this substrate by plasma CVD to form a base film.
[0123]
Further, an amorphous silicon film is formed to a thickness of 500 mm by a known plasma CVD method. Thereafter, this substrate is placed in the laser irradiation chamber 101 (FIG. 2).
[0124]
A mixed gas of helium 80% and oxygen 20% is introduced from the gas supply unit 109 into the laser irradiation chamber 101 in which the substrate is placed. The pressure in the laser irradiation chamber 101 is kept at atmospheric pressure or reduced pressure, for example, 0.02 to 0.5 Torr. The heating temperature of the substrate is 100 to 600 ° C., for example, 350 ° C.
[0125]
Then, the surface of the amorphous silicon film on the substrate is oxidized by oxygen in the atmosphere, and a silicon oxide film having a thickness of 10 to 100 mm is formed.
[0126]
At the same time, organic substances adhering to the surface of the amorphous silicon film are removed as volatile oxides by activated or ozonated oxygen.
[0127]
With the laser irradiation chamber 101 in a helium atmosphere, the amorphous silicon film is irradiated with linear laser light while moving the stage 106.
[0128]
The linear laser beam has a size of 0.34 mm width × 135 mm length on the irradiated surface. Energy density is 100mJ / cm ² ~ 400mJ / cm ² For example, 200 mJ / cm ² And A linear laser beam is scanned by moving the stage 106 in one direction at 2.5 mm / s. The oscillation frequency of the laser is 200 Hz.
[0129]
In this case, if attention is paid to one point on the irradiated surface, 10 to 50 shots of laser light are irradiated.
[0130]
In this way, by scanning and irradiating linear laser light in a helium / oxygen atmosphere, the amorphous silicon film is crystallized to become a crystalline silicon film.
[0131]
The produced crystalline silicon film has a clean film quality and is excellent in crystallinity and film homogeneity.
[0132]
Example 6
In this embodiment, plasma is generated in a helium atmosphere, and laser annealing is performed in the plasma atmosphere.
[0133]
A cross-sectional view of the laser annealing apparatus used in Example 6 is shown in FIG. A top view of FIG. 6 is shown in FIG. 6 and 7, the same components as those in FIGS. 2 and 3 are denoted by the same reference numerals.
[0134]
A gas mixture of helium, hydrogen, and oxygen is supplied from the gas supply unit 110 to the laser irradiation chamber 101. The mixing ratio of each gas is appropriately set as necessary. Here, 77% helium, 3% hydrogen, and 20% oxygen. The pressure in the laser irradiation chamber 101 is maintained at 0.02 to 0.03 Torr by the vacuum exhaust pump 108. Further, the preheating chamber, the slow cooling chamber, and the substrate transfer chamber are similarly decompressed.
[0135]
A substrate 401 to be processed on which an amorphous silicon film is formed is placed on a stage in the laser irradiation chamber 101 in the same manner as in the third embodiment. Then, the substrate is heated by a heater disposed in the table 106 and reaches a predetermined temperature, for example, 350 ° C.
[0136]
When the substrate 401 to be processed is heated in the laser irradiation chamber without being preheated, it is heated to 350 ° C. in about 1000 seconds.
[0137]
At this time, the surface of the amorphous silicon film on the substrate is oxidized by the action of oxygen in the atmosphere, and a thin silicon oxide film of 10 to 100 mm is formed.
[0138]
Next, high-frequency energy (13.56 MHz) is applied to the pair of electrodes 601 from the high-frequency power source 602 with an output of 400 W. Then, helium, oxygen, and hydrogen are all activated by the plasma. In particular, activated helium is kept in an active state for a relatively long time, and this influence also promotes the activity of oxygen and hydrogen.
[0139]
Due to the action of oxygen plasma, organic substances adhering to the substrate surface are separated by impact and removed as volatile oxides. Alternatively, the remaining organic substance is taken into the thin silicon oxide film.
[0140]
Hydrogen plasma also has an organic substance removing action. The target from which the oxygen plasma and the hydrogen plasma are removed is an organic substance having different carbon bonds. Therefore, by forming oxygen plasma and hydrogen plasma, organic substances present on the surface of the substrate to be processed can be more effectively removed.
[0141]
Further, heating at 300 ° C. to 600 ° C., particularly preferably about 300 to 350 ° C. is performed at the time of laser light irradiation, thereby promoting the annealing effect by laser light irradiation and simultaneously performing hydrogen heat treatment with hydrogen plasma. It can be carried out. This has an effect of compensating for defects and dangling bonds existing on the surface of the silicon film and in the film.
[0142]
Further, in FIG. 6, since the pair of electrodes 601 are provided with approximately the same size as the side surface of the laser irradiation chamber, plasma is formed throughout the laser irradiation chamber. Therefore, organic substances adhering to the inside of the laser irradiation chamber can be removed and cleaned by the action of oxygen and hydrogen plasma.
[0143]
The various actions of the oxygen plasma and hydrogen plasma are promoted by helium in the plasma state.
[0144]
In the above process, when the substrate to be processed is heated in the preheating chamber and the substrate to be processed is heated to the heating temperature at the time of laser irradiation or a temperature close to the heating temperature, the substrate is disposed in the laser irradiation chamber. Time until laser irradiation becomes possible is greatly shortened. The preheating temperature is increased or decreased with respect to the heating temperature during laser irradiation as necessary.
[0145]
In this case, if the heating in the preheating chamber is performed in a helium atmosphere, an oxide film due to the air atmosphere is not formed on the upper surface of the silicon film during the preheating, so that impurities in the air are mixed into the silicon film after laser annealing. Can be prevented.
[0146]
Further, in order of the process, first, plasma in an oxygen, hydrogen, and helium mixed atmosphere is formed in the laser irradiation chamber, and the pre-heated substrate to be processed is carried into the laser irradiation chamber in that state to perform laser processing. You may do it. In this way, in addition to shortening the substrate heating time in the laser irradiation chamber, a thin silicon oxide film is formed on the silicon film in an extremely short time of several seconds to several tens of seconds by the oxidation action of oxygen plasma, and laser irradiation is performed. It can be carried out. Therefore, the laser irradiation process can be further shortened.
[0147]
Needless to say, the step shown in Example 6 may be performed with a mixed gas of helium and only one of hydrogen and oxygen.
[0148]
Example 7
In this embodiment, the temperature is raised in a helium atmosphere in one laser irradiation chamber, and laser irradiation is performed while being exposed to an oxidizing atmosphere. The amount of oxidizing gas mixed in the helium atmosphere is minimized, and the helium atmosphere The present invention relates to a configuration that minimizes a decrease in thermal conductivity.
[0149]
FIG. 8 shows a cross-sectional view of the laser irradiation apparatus shown in this embodiment. FIG. 9 shows a top view of FIG. 8 and 9, the same reference numerals are used when the same parts as those in FIGS. 2 and 3 are displayed.
[0150]
8 and 9, helium is supplied from the gas supply unit 109 into the laser irradiation chamber 101 to form a 100% helium atmosphere.
[0151]
A hood 801 is provided in the laser irradiation chamber 101 so as to surround the vicinity of the linear laser light irradiation position 802.
[0152]
A substrate to be processed 401 is disposed in the laser irradiation chamber, and the substrate to be processed is heated to a predetermined temperature in a helium atmosphere at a high speed.
[0153]
After the heating of the substrate to be processed, ozone / oxygen mixed gas or oxygen is supplied into the hood 801 from the gas supply unit 803 as the oxidizing gas as ozone or an ozone-containing gas. With this configuration, the oxidizing gas is supplied only in the vicinity of the laser beam irradiation position 802 on the substrate to be processed, and an oxidizing atmosphere is partially formed.
[0154]
Organic substances on the substrate to be processed are oxidized and removed by the action of the oxidizing atmosphere. A silicon oxide film having a thickness of 100 mm or less is formed on the upper surface of the silicon film on the substrate to be processed. By performing laser annealing with the thin silicon oxide film formed, the crystallinity and homogeneity of the crystalline silicon film after annealing are improved.
[0155]
The time for which the substrate to be processed is exposed to the oxidizing gas can be controlled by the size of the inside of the hood 801 and the moving speed of the table 106 with respect to the moving direction of the substrate.
[0156]
When the laser irradiation process is completed, the supply of the oxidizing gas into the hood 801 is stopped.
[0157]
In the configuration shown in Embodiment 7, the laser irradiation chamber is evacuated by the vacuum exhaust pump 108 while maintaining a predetermined pressure during or after laser irradiation. Helium is supplied into the laser irradiation chamber constantly or as needed.
[0158]
On the other hand, a trace amount of oxidizing gas is supplied to the vicinity of the substrate surface by the hood to form an oxidizing atmosphere only partially. The supply amount of the oxidizing gas is much smaller than the supply amount of helium.
[0159]
This makes it possible to extremely reduce the amount of oxidant gas mixed into the helium atmosphere in the laser irradiation chamber even though the upper surface of the substrate to be processed is processed with the oxidant gas.
[0160]
As a result, even if the processing of one substrate to be processed is completed and taken out from the laser irradiation chamber, and immediately after that, the substrate to be processed next is transferred into the laser irradiation chamber, the helium atmosphere is almost 100% helium concentration. Is maintained at. Accordingly, it is possible to obtain the maximum effect of high-speed temperature rise in the helium atmosphere while sufficiently obtaining the effect of laser annealing in the oxidizing atmosphere. Thereby, high throughput can be obtained when a plurality of substrates are processed continuously.
[0161]
In the configuration of the seventh embodiment, only pure oxygen not containing ozone is supplied into the hood 801 and irradiated with laser light that is ultraviolet light, whereby the oxygen in the hood is ozonized, and the upper surface of the substrate to be processed is ozone. It is also possible to supply In particular, if the inside of the hood 801 has a small area that surrounds a linear laser beam having a line width of several millimeters, the oxygen inside the hood is sufficiently ozonized by laser irradiation. If it does in this way, the apparatus for producing | generating ozone can also be made unnecessary.
[0162]
In the configuration of the laser irradiation chamber shown in FIGS. 8 and 9, by supplying ozone or an ozone-containing gas so as to flow downward from above the hood 801, organic substances and inorganic substances flying from the substrate to be processed by laser irradiation can be obtained. Attachment to the laser irradiation window 104 can also be prevented. In addition, if the lower end of the hood is close to about several millimeters from the upper surface of the substrate to be processed, the flight of organic matter or inorganic matter to the outside of the hood is hindered. Therefore, a cleaning process in the laser irradiation chamber is not required.
[0163]
Example 8
Example 8 relates to another structure for performing laser light irradiation in a helium atmosphere after a substrate to be processed is processed in an oxidizing atmosphere.
[0164]
First, in one processing chamber, the upper surface of the substrate to be processed is oxidized with oxygen, ozone, an ozone-containing gas, or oxygen plasma to remove organic substances and form a thin oxide film.
[0165]
Next, the substrate to be processed is transferred to a laser irradiation chamber while maintaining a clean atmosphere, and laser irradiation is performed in a helium atmosphere.
[0166]
In the case where the oxidation process is performed in a container different from the laser irradiation, it is necessary to have a function of keeping the substrate to be processed from being exposed to the outside air and maintaining a clean atmosphere.
[0167]
For example, it is necessary to have a so-called multi-chamber configuration in which the oxidation treatment chamber and the laser irradiation chamber are connected via a gate valve. It is preferable to use a helium atmosphere as a clean atmosphere between the chambers when moving the substrate, because a high temperature increase in the helium atmosphere can be performed immediately after the substrate is carried into the laser irradiation chamber.
[0168]
In this case, if the atmosphere at the time of laser irradiation is an atmosphere containing hydrogen or hydrogen and oxygen in helium, or a plasma atmosphere thereof, hydrogen heat treatment can be performed simultaneously. In this case, it is important to heat the substrate to about 300 to 600 ° C., particularly preferably to 300 to 350 ° C.
[0169]
Example 9
Example 9 shows a configuration in which the step of oxidizing the irradiated portion of the substrate to be processed shown in Example 8 and then performing laser light irradiation is performed in a laser irradiation chamber.
[0170]
FIG. 10 shows a cross-sectional view of the apparatus shown in this embodiment. FIG. 11 shows a top view. 10 and 11, the same reference numerals are used when the same parts as those shown in FIGS. 2 and 3 are displayed.
[0171]
As shown in FIGS. 10 and 11, the hood 1001 is disposed on the near side of the position where the laser beam is scanned and irradiated. That is, the laser beam irradiation position 1002 is in the region of the substrate transported by the moving mechanism 107 that has passed through the lower portion of the hood 1001.
[0172]
Similarly to the seventh embodiment, ozone or an ozone-containing gas, for example, a mixed gas of ozone and oxygen, or oxygen is supplied from the gas supply unit 1003 to the hood 1001.
[0173]
Further, helium and hydrogen are supplied from the gas supply units 109 and 110, and the laser irradiation chamber becomes a helium atmosphere.
[0174]
With such a configuration, the substrate to be processed carried into the laser irradiation chamber is heated at a high speed by the action of the helium atmosphere to a predetermined temperature.
[0175]
After the heating of the substrate to be processed, an oxidizing gas such as ozone is supplied from the gas supply unit 1003 into the hood 1001. Then, an oxidizing atmosphere is partially formed in a region on the substrate to be processed before being irradiated with laser light.
[0176]
The upper surface of the substrate to be processed is first oxidized under the hood 1001 to remove organic substances and form a thin silicon oxide film. The oxidized region can be irradiated with laser light in a helium atmosphere or a mixed atmosphere of helium and hydrogen or another gas.
[0177]
In this case, the time during which the substrate to be processed is exposed to ozone can be controlled by the size of the hood 1001 in the substrate moving direction and the moving speed of the table 106.
[0178]
The configuration of the ninth embodiment is similar to that of the seventh embodiment. While performing the oxidation process, the high-temperature temperature rise by the action of the helium atmosphere can be similarly performed over the processing of a plurality of substrates. Can be obtained with high throughput.
[0179]
Furthermore, hydrogen is mixed in helium and heated at 300 to 600 ° C., preferably 300 to 350 ° C., so that hydrogen heat treatment can be performed simultaneously, higher throughput can be realized, and the manufacturing process can be shortened.
[0180]
Example 10
Example 10 shows another configuration of the sample heating method during laser annealing.
FIG. 12 shows a cross-sectional view of the apparatus shown in this embodiment. FIG. 13 shows a top view of FIG. 12 and 13, the same reference numerals are used when the same parts as those in FIGS. 2 and 3 are displayed.
[0181]
In the tenth embodiment, as shown in FIGS. 12 and 13, the substrate 401 as a sample is supported by pins 1201 on the stage 111 in a helium atmosphere, so that the substrate 401 is not brought into close contact with the upper surface of the stage 111. 111 is arranged so as to float from the upper surface. Then, helium or a mixed gas of helium and another gas between the substrate and the stage is heated by a heater provided in the table 106. Then, the substrate 301 is heated by the heated gas.
[0182]
In this way, the substrate is disposed with a predetermined gap with respect to the heater, and the substrate is heated via the gas. By doing so, the diffusion of heat in the substrate is made uniform, and the temperature distribution in the substrate surface can be made more uniform. As a result, the in-plane homogeneity of the crystalline silicon film obtained after laser annealing can be improved.
[0183]
In this configuration, a favorable result is obtained when the specific heat of the gas is high. Therefore, an atmosphere of helium having a high specific heat is extremely preferable.
[0184]
The gap between the substrate 401 and the stage 111 is about 0.1 to 5.0 mm, preferably about 0.5 to 2.0 mm. This interval improves the heating efficiency. If this interval is too wide, the heating efficiency is lowered, so care must be taken.
[0185]
Here, the configuration in which the substrate 401 is supported by pins is shown as an example corresponding to FIGS. 2 and 3, but it is obvious that the configuration can be implemented in other configurations corresponding to FIGS. 6 to 11.
[0186]
Example 11
The present embodiment relates to a configuration in which a helium atmosphere is set only during heating immediately after the substrate is loaded, and another atmosphere is set during laser irradiation.
[0187]
In some cases, the substrate heating atmosphere is a helium atmosphere, the temperature is increased at a high speed, and the laser irradiation atmosphere is other than helium, for example, nitrogen or an atmosphere in which oxygen or hydrogen is mixed in nitrogen. By laser annealing in a nitrogen atmosphere, there is an effect that ridges (roughness) on the film surface due to laser irradiation are reduced as compared with a helium atmosphere.
[0188]
In such a case, for example, using the apparatus shown in FIG. 2, helium is introduced from the gas supply unit 109 to form a helium atmosphere, and the substrate heating temperature is stabilized at a predetermined temperature by increasing the temperature at a high speed. After that, or once the inside of the laser irradiation chamber is in a reduced pressure state, a gas such as nitrogen is introduced from the gas supply unit 110, and this can be realized.
[0189]
At this time, it is necessary to heat the introduced gas and the laser irradiation chamber to some extent so that the substrate temperature does not decrease due to the introduction of the gas.
[0190]
On the other hand, although the exhaust and supply of gas depends on the volume of the laser irradiation chamber, it takes several minutes to several tens of minutes at the fastest. In particular, when processing substrates continuously, if the atmosphere is changed for each substrate, the merit of high-speed temperature rise by the helium atmosphere is diminished.
[0191]
In view of this, a different atmosphere is formed in advance between the region where the substrate to be processed is heated and the region where laser irradiation is performed, and the substrate to be processed moves between the two atmospheres.
[0192]
FIG. 14 shows a cross-sectional view of the laser irradiation apparatus shown in this embodiment. In FIG. 14, the same reference numerals are used when the same parts as those in FIG. 2 are displayed.
[0193]
In the laser irradiation apparatus in FIG. 14, a shutter 1403 is provided between a heating chamber 1401 for heating a substrate to be processed and a laser irradiation chamber 1402. That is, the heating chamber and the laser irradiation chamber are provided adjacent to each other.
[0194]
The raising / lowering means 1408 moves the substrate 401 to be processed between the heating chamber 1401 and the laser irradiation chamber.
[0195]
When the shutter 1403 is closed, the heating chamber 1401 and the laser irradiation chamber 1402 are separated from each other so that the two atmospheres are not mixed as much as possible.
[0196]
Before the substrate is carried into the heating chamber, the stage 111 is arranged in the heating chamber 1401 by the lifting / lowering means 1408 together with the base 106 having the heater inside.
[0197]
The heating chamber 1401 is filled with helium from the gas supply unit 1404 and becomes a helium atmosphere. The inside of the heating chamber 1401 is maintained at a predetermined pressure of atmospheric pressure or reduced pressure, for example, 0.02 to 0.5 Torr by a vacuum exhaust pump 1405.
[0198]
In the laser irradiation chamber 1402, an atmosphere for laser irradiation, for example, a mixed gas of nitrogen, oxygen, and hydrogen is introduced from the gas supply unit 1404.
[0199]
When the atmosphere in the laser irradiation chamber 1402 is a mixed atmosphere of nitrogen and oxygen, oxygen is preferably contained in an amount of about 5 to 50% (atmospheric pressure). If it is 5% or less, it is difficult to obtain effects such as improvement of crystallinity and removal of organic substances by adding oxygen. If it is 50% or more, the merit of using a nitrogen atmosphere is reduced.
[0200]
When a mixed atmosphere of nitrogen and hydrogen is used, it is preferable that hydrogen is contained at 3% or less. Explosion may occur when hydrogen exceeds 3%.
[0201]
When the mixed gas of nitrogen, hydrogen, and oxygen is used, the ratio of the combined gas of hydrogen and oxygen to nitrogen is preferably about 3 to 50%. If it is 3% or less, the mixing effect cannot be obtained, and if it is 50% or more, the merit of using a nitrogen atmosphere is reduced. At this time, hydrogen is preferably about 0.1 to 10% of oxygen. If it is less than 0.1%, the effect of containing hydrogen cannot be obtained, and if it exceeds 10%, there is a risk of explosion.
[0202]
Further, the inside of the laser irradiation chamber 1402 is maintained at a predetermined pressure of atmospheric pressure or reduced pressure, for example, 0.02 to 0.5 Torr by a vacuum exhaust pump 1407.
[0203]
First, the substrate 401 to be processed is transferred from the substrate transfer chamber via the gate valve 501 and placed on the stage 111 in the heating chamber 1401.
[0204]
After the gate valve 501 is closed, the substrate 401 to be processed is heated by the heater in the table 106, heated at a high speed by the action of the helium atmosphere, and stabilized at a predetermined temperature.
[0205]
Next, the shutter 1403 is opened, and the substrate 401, the stage 111, and the stage 106, which are stabilized at a predetermined temperature, are moved to the laser irradiation chamber 1402 by the lifting / lowering means 1408. Here, the platform 106 is fixed to the moving means 107 and can move in the horizontal direction. The shutter 1403 is immediately closed after moving into the laser irradiation chamber of the substrate to be processed.
[0206]
Note that it is preferable to preheat the atmosphere in the laser irradiation chamber so as not to lower the temperature of the substrate moved into the laser irradiation chamber.
[0207]
The stage 106 moves at a predetermined speed by the moving means 107 in the laser irradiation chamber 1402. The substrate to be processed 401 on the stage 106 and the stage 111 is annealed with a linear laser beam in a nitrogen atmosphere containing oxygen and hydrogen.
[0208]
After the laser annealing is completed, the stage 106 moves to the lower part of the heating chamber. Then, the shutter 1403 is opened, the platform 106 on which the substrate to be processed is placed is moved again to the heating chamber 1401 in the helium atmosphere by the lifting / lowering means 1408, and the shutter is closed. Thereafter, the substrate moves to the substrate transfer chamber via the gate valve 501.
[0209]
With such a configuration, the step of heating and heating the substrate in a helium atmosphere and laser annealing in a nitrogen atmosphere can be performed in a shorter time. Further, it is possible to obtain both an improvement in throughput due to a high temperature increase in a helium atmosphere and an excellent film quality due to laser annealing in an atmosphere other than helium.
[0210]
Here, a configuration is shown in which the heating chamber is provided on the laser irradiation chamber, and the lifting means is used as the moving means between the substrate heating chamber and the laser irradiation chamber. However, the heating chamber may be provided on the side of the laser irradiation chamber via a shutter, and the substrate (and the stage and the stage) may be moved in the horizontal direction. Alternatively, only the substrate may be transferred between the heating chamber and the laser irradiation chamber using a robot arm or the like.
[0211]
In the above-described configuration in which the heating chamber and the laser irradiation chamber are adjacent to each other via the shutter, the atmosphere in both chambers may be slightly mixed due to the movement of the stage, the stage, and the substrate between the heating chamber and the laser irradiation chamber.
[0212]
As a method for preventing this, when the substrate is moved from the heating chamber to the laser irradiation chamber, the gas supply amount and the exhaust amount are controlled to set the pressure in the laser irradiation chamber higher than the pressure in the heating chamber. Similarly, when the substrate is moved from the laser irradiation chamber to the heating chamber, the pressure of the heating chamber is set higher than the pressure of the laser irradiation chamber. Thereby, it can prevent that the atmosphere of the room before a movement mixes in the room of a movement destination.
[0213]
In this case, the atmosphere of the destination room is slightly mixed in the room before the movement. However, while the shutter is closed, the atmosphere can be maintained by newly supplying the gas constituting the atmosphere in the chamber before the movement, that is, the chamber where the substrate is not currently arranged.
[0214]
As another method, there is a method in which a buffer chamber separated from both chambers by a shutter that can be opened and closed is provided between the laser irradiation chamber and the heating chamber. That is, when the substrate is moved from one chamber to the other chamber, the substrate (and the stage and the stage) is once moved to the buffer chamber, the shutter is closed, and the buffer chamber is shielded from the atmosphere of both chambers.
[0215]
By moving the table on which the substrate is placed in the buffer chamber, the atmosphere of the chamber before the movement is mixed into the buffer chamber. The buffer chamber may have the same atmosphere as that of the destination room in advance.
[0216]
Here, the gas is introduced into the buffer chamber so that the atmosphere in the buffer chamber is the same as that of the destination chamber. At this time, the pressure is controlled while exhausting with a vacuum exhaust pump.
[0217]
When the atmosphere in the buffer chamber becomes the same as the atmosphere in the destination room in this way, the shutter on the destination side is opened and the platform on which the substrate is placed is moved into the destination room. Then close the shutter.
[0218]
In this way, it is possible to completely prevent mixing of the atmosphere due to the movement of the substrate between the laser irradiation chamber and the heating chamber.
[0219]
In this embodiment, the substrate before laser processing and the substrate after laser processing are transferred between the laser irradiation apparatus and the substrate transfer chamber through the same chamber (heating chamber 1401). In this way, the apparatus configuration is simple, but after the laser processing is completed, the substrate is once returned to the heating chamber and then transferred to the substrate transfer chamber. If the substrate is not transferred from the heating chamber, a new substrate to be processed is loaded. Can not do it.
[0220]
Therefore, the substrate in which the substrate before laser processing and the substrate after laser processing are arranged may be different, and the substrate may be carried out and loaded in different chambers. That is, a substrate to be laser processed is placed in a first chamber in a helium atmosphere, heated at a high temperature and heated, and laser processing is performed in the laser irradiation chamber. The processed substrate may be placed in a second chamber of helium or another atmosphere, and then the substrate may be carried out to the substrate transfer chamber.
[0221]
By doing so, the next substrate can be heated while one substrate to be processed is processed in the laser irradiation chamber, and the throughput is further improved.
[0222]
In this embodiment, as the structure of the laser irradiation chamber, the structure of another laser irradiation chamber shown in another embodiment of this specification can be used.
[0223]
【The invention's effect】
By performing the annealing process on the semiconductor film by laser light irradiation in a helium atmosphere, the heating temperature raising time of the semiconductor film or the substrate provided with the semiconductor film can be shortened and the throughput can be improved.
[Brief description of the drawings]
FIG. 1 is a view showing a relationship between an elapsed time after loading a substrate into the apparatus and a substrate temperature.
FIG. 2 is a diagram showing a laser irradiation chamber in an example.
FIG. 3 is a top view of FIG. 2;
FIG. 4 is a diagram showing a manufacturing process of an example.
FIG. 5 is a top view of the laser annealing apparatus in the embodiment.
FIG. 6 is a cross-sectional view of an example of a laser irradiation apparatus.
7 is a top view of FIG. 6. FIG.
FIG. 8 is a cross-sectional view of an example of a laser irradiation apparatus.
FIG. 9 is a top view of FIG.
FIG. 10 is a cross-sectional view of an example of a laser irradiation apparatus.
11 is a top view of FIG.
FIG. 12 is a cross-sectional view of an example of a laser irradiation apparatus.
13 is a top view of FIG.
FIG. 14 is a cross-sectional view of an example of a laser irradiation apparatus.
[Explanation of symbols]
101 Laser irradiation room
102 Laser oscillator
103 mirror
104 windows
106 units
107 Movement mechanism
108 Vacuum pump
109, 110 Gas supply part
111 stages
112 Optical system
401 substrate
402 Silicon oxide film (underlying film)
403 Crystallized silicon film
404 Silicon oxide film
405 Island area
406 Gate insulation film
407 Gate electrode
408 source
409 drain
410 Channel formation region
411 Interlayer insulation film
412 Source electrode / wiring
413 Drain electrode / wiring
420 Helium atmosphere
501 Gate valve
502 Substrate transfer chamber
503 Alignment room
504 substrate
505 Robot arm
506 Load / unload room
507 Gate valve
508 Preheating chamber
509 Gate valve
510 annealing room
511 Gate valve
512 cassette
601 A pair of electrodes
602 High frequency power supply
801 Food
802 Laser light irradiation position
803 Gas supply unit
1001 Food
1002 Laser beam irradiation position
1003 Gas supply unit
1201 pin
1401 Heating chamber
1402 Laser irradiation room
1403 Shutter
1404, 1406 Gas supply unit
1405, 1407 Vacuum pump
1408 Lifting means

Claims (16)

A semiconductor film disposed in a helium atmosphere containing hydrogen is irradiated with laser light to the surface of the semiconductor film while heating to a predetermined temperature,
The semiconductor processing method , wherein the helium atmosphere is in a plasma state . A semiconductor film placed in a helium atmosphere containing oxygen is irradiated with laser light on the surface of the semiconductor film while heating to a predetermined temperature,
The semiconductor processing method, wherein the helium atmosphere is in a plasma state. A semiconductor film disposed in a helium atmosphere containing hydrogen and oxygen is irradiated with laser light on the surface of the semiconductor film while heating to a predetermined temperature,
The semiconductor processing method, wherein the helium atmosphere is in a plasma state. After the semiconductor film is placed in the first helium atmosphere and heated to a predetermined temperature,
The semiconductor film is irradiated with laser light on the surface of the semiconductor film in a second helium atmosphere containing at least one of hydrogen or oxygen,
The semiconductor processing method, wherein the second helium atmosphere is in a plasma state. After the semiconductor film is placed in the first helium atmosphere and heated to a predetermined temperature,
While heating the semiconductor film in a second helium atmosphere containing at least one of hydrogen or oxygen, the surface of the semiconductor film is irradiated with laser light,
The semiconductor processing method, wherein the second helium atmosphere is in a plasma state. In claim 4 or claim 5,
The semiconductor processing method according to claim 1, wherein the first helium atmosphere contains at least one of hydrogen and oxygen. After placing the semiconductor film in a helium atmosphere containing at least one of hydrogen or oxygen and heating to a predetermined temperature,
A semiconductor processing method, comprising: irradiating a surface of the semiconductor film with laser light in an atmosphere in which the helium atmosphere is in a plasma state. After placing the semiconductor film in a helium atmosphere containing at least one of hydrogen or oxygen and heating to a predetermined temperature,
A semiconductor processing method comprising irradiating a surface of the semiconductor film with laser light while heating the semiconductor film in an atmosphere in which the helium atmosphere is in a plasma state. Irradiating the surface of the semiconductor film with laser light while heating the semiconductor film placed in a helium atmosphere containing hydrogen to a predetermined temperature,
The method for manufacturing a thin film transistor, wherein the helium atmosphere is in a plasma state. A semiconductor film placed in a helium atmosphere containing oxygen is irradiated with laser light on the surface of the semiconductor film while heating to a predetermined temperature,
The method for manufacturing a thin film transistor, wherein the helium atmosphere is in a plasma state. A semiconductor film disposed in a helium atmosphere containing hydrogen and oxygen is irradiated with laser light on the surface of the semiconductor film while heating to a predetermined temperature,
The method for manufacturing a thin film transistor, wherein the helium atmosphere is in a plasma state. After the semiconductor film is placed in the first helium atmosphere and heated to a predetermined temperature,
The semiconductor film is irradiated with laser light on the surface of the semiconductor film in a second helium atmosphere containing at least one of hydrogen or oxygen,
The method for manufacturing a thin film transistor, wherein the second helium atmosphere is in a plasma state. After the semiconductor film is placed in the first helium atmosphere and heated to a predetermined temperature,
While heating the semiconductor film in a second helium atmosphere containing at least one of hydrogen or oxygen, the surface of the semiconductor film is irradiated with laser light,
The method for manufacturing a thin film transistor, wherein the second helium atmosphere is in a plasma state. In claim 12 or claim 13,
The method for manufacturing a thin film transistor, wherein the first helium atmosphere contains at least one of hydrogen and oxygen. After placing the semiconductor film in a helium atmosphere containing at least one of hydrogen or oxygen and heating to a predetermined temperature,
A method for manufacturing a thin film transistor, wherein the semiconductor film is irradiated with laser light on a surface of the semiconductor film in an atmosphere in which the helium atmosphere is in a plasma state. After placing the semiconductor film in a helium atmosphere containing at least one of hydrogen or oxygen and heating to a predetermined temperature,
A method for manufacturing a thin film transistor, wherein the surface of the semiconductor film is irradiated with laser light while the semiconductor film is heated in an atmosphere in which the helium atmosphere is in a plasma state.

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