JP2003178979A - Method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique of forming a crystalline semiconductor film with orientation put in order by controlling the crystal orientation, and of obtaining a crystalline semiconductor film with reduced impurity concentration. <P>SOLUTION: The method comprises forming a first semiconductor region on a substrate transparent in a visible spectrum region, forming a barrier film covering the first semiconductor region, forming a heat insulating film covering the upper and side surfaces of the first semiconductor region through the barrier film, crystallizing the first semiconductor region by scanning a continuous oscillation laser beam from one end of the first semiconductor region to the other end of the same through the substrate, and forming a second semiconductor region by etching the first semiconductor region into a TFT active layer after removal of the protective film and the barrier film. A pattern of the second semiconductor region formed by the etching is formed such that a scanning direction of the laser beam and a channel length direction in the TFT are substantially coincident each other in order to smooth the drift of a carrier. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device using a laser annealing method. In particular, the present invention relates to a technique for crystallizing an amorphous semiconductor film by a laser beam or improving crystallinity.

[0002]

2. Description of the Related Art A technique for crystallizing an amorphous semiconductor film formed on a substrate such as glass by a laser annealing method has been developed. The laser annealing method here is a technique for recrystallizing a damaged layer or an amorphous layer formed on a semiconductor substrate or a semiconductor film, a technique for crystallizing an amorphous semiconductor film formed on a substrate, or a crystal. This refers to a technique for improving the crystallinity of a structured semiconductor film (crystalline semiconductor film). As a laser oscillator applied to laser annealing of semiconductors, a gas laser typified by an excimer laser and a solid-state laser typified by a YAG laser are usually used.

An example of a conventional laser annealing method is a method of uniformly irradiating a laser beam on the entire surface of an object to be irradiated, as disclosed in Japanese Patent Application Laid-Open No. 2-181419.
As disclosed in JP-A-62-104117,
A method of scanning a spot-shaped beam, or JP-A-8-
There is known a method in which a beam is processed into a linear beam by an optical system and is irradiated like a laser processing device disclosed in Japanese Patent Laid-Open No. 195357.

In the above-mentioned Japanese Patent Laid-Open No. 62-104117, the scanning speed of the laser beam is set to a beam spot diameter × 5000 / sec or more to polycrystallize the amorphous semiconductor film without completely melting it. It is a technology.
U.S. Pat. No. 4,330,363 discloses a technique in which a semiconductor region formed in an island shape is irradiated with a stretched laser beam to substantially form a single crystal region.

The characteristic of the laser annealing method is that, unlike the annealing method utilizing radiant heating or conduction heating, only the region that absorbs the energy of the laser beam can be selectively heated. For example, laser annealing using an excimer laser selectively and locally heats a semiconductor film to cause almost no thermal damage to a glass substrate,
It realizes crystallization and activation of semiconductor film.

The active use of laser annealing in recent years lies in the formation of a polycrystalline silicon film on a glass substrate.
This technique is applied to manufacture of a thin film transistor (TFT) used as a switching element of a liquid crystal display device. When an excimer laser is used, only a region where a semiconductor film is formed has a thermal effect, so that an inexpensive glass substrate can be used.

Since a TFT made of a polycrystalline silicon film crystallized by laser annealing can be driven at a relatively high frequency, it is possible to form not only a switching element provided in a pixel but also a driving circuit on a glass substrate. Has become. The design rule of the pattern is about 5 to 20 μm, and the driving circuit and the pixel portion each have a pattern of 10 ⁶ to 10 ⁷
About TFTs are built on the glass substrate.

[0008]

Crystallization of an amorphous silicon film using a laser annealing method is performed through a process of melting and solidifying. Specifically, formation of crystal nuclei and crystals from the nuclei are described. It is considered divided into stages such as growth. However, crystallization using a pulsed laser beam cannot control the generation position and generation density of crystal nuclei, and currently expects crystal nuclei to occur naturally. Therefore, the crystal grains are formed at arbitrary positions within the surface of the glass substrate, and the size thereof is as small as about 0.2 to 0.5 μm. Usually, a large number of defects are included in the crystal grain boundaries, and it is considered that this is a factor that limits the field effect mobility of the TFT.

In pulse laser annealing, which is said to form a non-melting region, crystal growth due to crystal nuclei becomes dominant, and it is not possible to increase the crystal grain size. Specifically, it is impossible to form a crystal having no crystal grain boundary in the channel region of the TFT and which can be regarded as a substantially single crystal at the device level.

Not only the crystal grain boundaries but also the generated defects or dislocations are generated when the volume of the film shrinks due to the densification accompanying the crystallization. In particular, it has been pointed out that defects caused by volume contraction are generated in the outer peripheral portion of a semiconductor film divided into islands when crystallized by a laser annealing method.

On the other hand, the method of crystallizing while melting and solidifying by scanning with a continuous wave laser beam is considered to be a method close to the zone melting method, and it is possible to increase the grain size by continuous crystal growth. Is believed to be. However, due to the crystallinity of the seed region that was first crystallized,
The problem is that the quality of the finally obtained crystal depends on it.

By the way, the wavelength of the laser beam capable of heating the semiconductor film exists in a wide range from the ultraviolet region to the infrared region, but the semiconductor film formed on the substrate or the semiconductor region formed separately is formed. For selective heating, it is considered preferable to apply a laser beam having a wavelength in the ultraviolet region to the visible light region in relation to the absorption coefficient of the semiconductor. However, the light of the solid-state laser, which can obtain a relatively high output even in the visible light region, has a large coherence length and interference occurs on the irradiation surface, and it is difficult to irradiate a uniform laser beam.

Further, in crystallization of a continuous wave laser beam having a melting state for a longer time than that of a pulsed laser beam, the ratio of impurities taken into the crystal from the outside increases and the segregation of impurities increases the crystallinity. Even if it is done, there is a problem that defects caused by impurities are formed and eventually the quality of the crystal deteriorates.

The present invention has been made in view of the above problems, and controls the crystal orientation to form a crystalline semiconductor film having a uniform orientation and a crystalline semiconductor film having a reduced impurity concentration. The purpose is to provide the technology to obtain.

[0015]

In order to solve the above problems, according to the structure of the present invention, at least a first semiconductor region is formed on a substrate having a light-transmitting property in a visible light region, and the first semiconductor region is formed. A barrier film covering the first semiconductor region and a heat insulating film covering the upper surface and the side surface of the first semiconductor region via the barrier film, and a continuous wave laser beam from one end to the other end of the first semiconductor region via the substrate. Is scanned to crystallize the first semiconductor region, the heat insulating film and the barrier film are removed, and then the first semiconductor region is etched to form a second semiconductor region to be an active layer of the TFT. The pattern of the second semiconductor region formed by etching has a laser beam scanning direction and a TF in order to smooth the drift of carriers.
It is formed so that the channel length direction at T is the same direction.

The heat insulating film is provided in order to prevent the first semiconductor region, which has been heated by the irradiation of the laser beam until it reaches a molten state, from being rapidly cooled after the irradiation of the laser beam and the crystal grains becoming finer. It is known that a large number of crystal nuclei are generated and microcrystallized when rapidly cooled from a molten state, but this can be prevented by providing a protective film. That is, by providing the heat insulating film, it is possible to slow the cooling rate and prolong the crystal growth time in the solidification process after the laser beam irradiation.

The barrier film is provided as an etching stopper when the heat insulating film is removed, and a silicon-based semiconductor material and silicon oxide or silicon nitride having selectivity for etching are used. Alternatively, aluminum nitride, aluminum oxide, or aluminum oxynitride can be used as a material having high thermal conductivity.

Impurity elements such as metals segregated in the first semiconductor region during crystallization are removed by gettering treatment. As the gettering treatment, after the heat insulating film and the barrier film are removed, an amorphous semiconductor film is formed over the first semiconductor region, the heat treatment is performed to segregate the metal element in the amorphous semiconductor film, and thereafter, The crystalline semiconductor film and the barrier film may be removed. By performing the gettering treatment after crystallizing the first semiconductor region, impurities such as a metal segregated in the semiconductor region are removed and a high-purity crystal can be obtained.

As the first semiconductor region, an amorphous semiconductor film formed on a substrate is etched to form a predetermined pattern. That is, it may be formed of an amorphous semiconductor. As another form, it may be pre-crystallized.

In that case, a method for manufacturing a semiconductor device is as follows. An amorphous semiconductor film is formed on a substrate, a catalytic element is added, and the amorphous semiconductor film is crystallized by heat treatment to form a crystalline semiconductor film. And the crystalline semiconductor film is etched to form a first semiconductor region, a barrier film covering the first semiconductor region is formed, and a heat insulating film covering the upper surface and the side surface of the first semiconductor region through the barrier film. And a continuous wave laser beam is scanned from one end of the first semiconductor region to the other end of the first semiconductor region through the substrate to modify the crystallinity of the first semiconductor region and remove the heat insulating film and the barrier film. After that, the first semiconductor region is etched so that the scanning direction of the laser beam and the T
The second semiconductor region is formed so as to be substantially aligned with the channel length direction in the FT so as to be in the same direction.

Alternatively, after forming an amorphous semiconductor film on a substrate and selectively adding a catalyst element, the amorphous semiconductor film is heated by heat treatment from a region to which the catalyst element is selectively added to the substrate. To form a crystalline semiconductor film by crystallizing in a direction parallel to, forming a first semiconductor region by etching the crystalline semiconductor film, forming a barrier film covering the first semiconductor region, and interposing the barrier film. A heat insulating film covering the upper surface and the side surface of the first semiconductor region is formed, and the continuous oscillation laser beam is scanned from one end to the other end of the first semiconductor region through the substrate to crystallize the first semiconductor region. After removing the heat insulating film and the barrier film, the first semiconductor region is etched to form the second semiconductor region so that the scanning direction of the laser beam and the channel length direction of the TFT are in the same direction. It is a thing.

A method for predetermining the crystal orientation of the second semiconductor region finally formed as the active layer of the TFT is as follows:
Before the crystallization of the first semiconductor region, a method of forming a seed region as a seed in contact with the first semiconductor region in advance is applied.

In that case, the method of manufacturing the semiconductor device of the present invention is such that the first amorphous semiconductor film is formed on the substrate, the catalytic element is added, and then the amorphous semiconductor film is crystallized by heat treatment. Forming a first crystalline semiconductor film, etching the first crystalline semiconductor film to form a seed crystal region, forming a second amorphous semiconductor film on the substrate, the second amorphous semiconductor film overlapping the seed crystal region, The amorphous semiconductor film is etched to form a first semiconductor region which at least partially overlaps with the seed crystal region, a barrier film covering the first semiconductor region is formed, and the first semiconductor region of the first semiconductor region is formed through the barrier film. A heat insulating film is formed to cover the upper surface and the side surface, and the continuous oscillation laser beam is scanned from one end overlapping the seed crystal region to the other end through the substrate to crystallize the first semiconductor region. The heat insulation film and the barrier film. After, the first semiconductor region and the seed crystal area by etching, in which the channel length direction in the scanning direction and TFT of the laser beam to form a second semiconductor region so as to have the same direction.

Alternatively, a first amorphous semiconductor film containing silicon and germanium is formed on a substrate, a catalytic element is added, and then the amorphous semiconductor film is crystallized by heat treatment to obtain a first crystalline material. A semiconductor film is formed, the first crystalline semiconductor film is etched to form a seed crystal region, and a second amorphous semiconductor film overlapping the seed crystal region is formed on the substrate. Is etched to form a first semiconductor region at least partially overlapping the seed crystal region, the heat insulating film and the barrier film are removed, and then the first semiconductor region and the seed crystal region are etched to obtain a laser beam scanning direction. And the second semiconductor region is formed such that the channel length direction in the TFT is the same as the channel length direction in the TFT.

By adding a catalytic element to an amorphous semiconductor film containing silicon and germanium and crystallizing it, {10
A crystalline semiconductor film having a high orientation ratio of the 1} plane can be obtained. As a result of experiments, the concentration of germanium required to exhibit such an action may be 0.1 atom% or more and 10 atom% or less, preferably 1 atom% or more and 5 atom% or less with respect to silicon. When the concentration of germanium exceeds the upper limit value, natural nuclei (nuclei generated regardless of the compound with the added metal element) generated as an alloy material of silicon and germanium become remarkable, and the obtained polycrystalline semiconductor film However, the orientation ratio cannot be increased. Further, if it is at most the lower limit value, sufficient strain cannot be generated and the orientation ratio cannot be increased. By using this as a seed region, the orientation rate of the finally formed third semiconductor region can be increased, and a single-oriented crystalline semiconductor can be obtained.

Fe, Co, N are used as catalyst elements applied to the amorphous semiconductor film containing silicon and germanium.
i, Ru, Rh, Pd, Os, Ir, Pt, Cu, Au
One element or a plurality of elements selected from are used. The thickness of the amorphous semiconductor film is 10 nm to 200 nm. The metal element is added to the amorphous silicon film and heat treatment is performed to form a compound (silicide) of silicon and the metal element, and the compound is diffused to promote crystallization. Germanium added to the amorphous silicon film does not react with this compound and exists locally around it, causing local strain. This strain acts to increase the critical radius of nucleation, reduces the nucleation density, and has the effect of limiting the crystal orientation.

In the crystalline semiconductor film, the gettering treatment can be applied as a means for removing the catalytic element used for crystallization or the impurities taken in from the outside by passing through the molten state. An amorphous semiconductor or a crystalline semiconductor to which a periodic group 18 element (rare gas element) such as phosphorus or argon is added is suitable for a gettering site (a region in which impurities are segregated) that forms a strain field. By the gettering treatment, it is possible to remove the above-mentioned catalyst element or other metal element mixed in the process of crystallization,
The defect density resulting from impurities can be reduced.

By the above method, the second semiconductor region formed by etching the first semiconductor region can be a crystal that can be regarded as a substantially single crystal. That is, by scanning the continuous wave laser beam in the same direction (parallel direction) as the channel length direction of the TFT, a crystalline semiconductor film composed of a single crystal grain can be formed over the entire channel formation region. It will be possible.

In the structure of the above invention, as the substrate, a non-alkali glass represented by barium borosilicate glass or aluminoborosilicate glass, or a semiconductor substrate such as quartz can be applied.

The laser oscillator applied to the present invention includes:
A gas laser oscillator or a solid laser oscillator is applied, and a laser oscillator capable of continuous oscillation is particularly preferably applied. As a continuous wave solid-state laser oscillator,
C in crystals such as YAG, YVO ₄ , YLF, YAlO ₃
A laser oscillation device using a crystal doped with r, Nd, Er, Ho, Ce, Co, Ti or Tm is applied.
The wavelength of the fundamental wave depends on the material to be doped, but 1
It oscillates at wavelengths from μm to 2 μm. In order to crystallize the amorphous semiconductor film, a laser beam having a wavelength in the visible region to the ultraviolet region is applied in order to selectively absorb the laser beam in the semiconductor film, and the second to fourth harmonics of the fundamental wave are applied. It is preferable to apply harmonics. Typically, when crystallizing an amorphous semiconductor film, a Nd: YVO ₄ laser (fundamental wave 1064
nm) second harmonic (532 nm) is used. Besides, a gas laser oscillator such as an argon laser or a krypton laser can be applied.

In any case, because of the relationship with the absorption coefficient of the semiconductor film, the wavelength of the continuous wave laser beam is 400 nm.
To 700 nm is desirable. With light in the longer wavelength region, the absorption coefficient of the semiconductor is small, and if the power density is increased in order to melt the semiconductor, the substrate will be thermally damaged. Further, with light in a wavelength range shorter than that, most of the light is absorbed by the surface of the semiconductor and cannot be heated from the inside, so that random crystal growth becomes dominant due to the influence of the surface state.

Since the laser beam emitted from the solid-state laser oscillator has a strong coherence and causes interference on the irradiation surface, a plurality of laser beams emitted from different laser oscillators are used as a means for canceling the interference. It will be configured to be overlapped in. With such a structure, not only interference can be removed but also the substantial energy density in the irradiation portion can be increased. Further, as another means, a plurality of laser beams emitted from different laser oscillation devices may be superposed on the same optical axis in the middle of the optical system.

As a structure of the laser processing apparatus provided with the means for eliminating the interference, there are n (n = natural number) optical systems, the nth optical system is an nth laser oscillator,
Consists of deflection means for operating the laser beam in the n-th Y-axis direction, deflection means for scanning the laser beam in the n-th X-axis direction, and n-th f.theta. Lens. The deflected and deflected n laser beams can be realized by irradiating the semiconductor film which is the object to be processed at substantially the same position. A galvanometer mirror can be applied as the deflecting means.

With the configuration of the above laser processing apparatus, a laser beam having an energy density sufficient to melt a semiconductor can be irradiated without causing interference in the irradiation section, and the position of the laser beam is controlled by the deflecting means. By performing the scanning, it is possible to process only the specific region in which the semiconductor region is formed even if the substrate has a large area. Therefore, the throughput in the crystallization process can be improved.

The term "amorphous semiconductor film" as used in the present invention means, in a narrow sense, not only a film having a completely amorphous structure but also a state in which fine crystal grains are contained, or a so-called microcrystalline semiconductor. The film includes a semiconductor film that locally includes a crystal structure.
Typically, an amorphous silicon film is applied, and in addition, an amorphous silicon germanium film, an amorphous silicon carbide film, or the like can be applied.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The perspective view shown in FIG.
It shows a state in which the blocking layer 102, the first semiconductor region 103, the barrier film 104, and the heat insulating film 105 are formed on the substrate 101. A non-alkali glass substrate can be used as the substrate 101. As the semiconductor material forming the first semiconductor region 103, silicon, a compound or alloy of silicon and germanium, or a compound or alloy of silicon and carbon is used. The most suitable material among them is silicon. The thickness of the first semiconductor region 103 is 30 to 200 nm.

As the substrate 101, a non-alkali glass typified by barium borosilicate glass or aluminosilicate glass, or a semiconductor substrate such as quartz can be used. It is also possible to apply a synthetic resin such as polyethylene naphthalate or polyether sulfone.

From the first semiconductor region 103, the second semiconductor region 106 forming the active layer of the TFT at the position shown by the dotted line.
Is formed. The second semiconductor region 106 is the semiconductor region 1
It is formed inside so as not to reach the end of 03. Here, the active layer includes a channel formation region of a TFT and an impurity region whose valence electrons are controlled, such as a source or drain region.

The laser beam 107 is applied to the semiconductor region 103.
And scan in one direction to crystallize. Alternatively, reciprocal scanning may be performed in parallel with the direction of the first scanning. The laser beam uses a wavelength band which is transmitted through the substrate and is mainly absorbed by the semiconductor material forming the first semiconductor region. When the semiconductor material is amorphous silicon, a laser beam having a wavelength in the visible light region of 400 to 700 nm is irradiated in consideration of the film thickness of amorphous silicon, depending on the hydrogen content. By this operation, the first semiconductor region 1 is transmitted through the substrate 101.
03 and the heat retention region 105 can be selectively heated. For this wavelength band, the absorption coefficient of amorphous silicon is approximately 10 ³ to 10 ⁵ cm ^-1 . Therefore, the most suitable laser beam is Cr, Nd, Er, Ho, Ce, Co, Ti for crystals such as YAG, YVO ₄ , YLF and YAlO _3.
Or a continuous wave laser beam emitted from a laser oscillator using a Tm-doped crystal,
The second harmonic is used to obtain a laser beam in the wavelength range of 700 nm. For example, when an Nd: YVO ₄ laser is used, a laser beam having a wavelength of 532 nm can be obtained as the second harmonic.

Specifically, the penetration depth of the first semiconductor region 103 formed of an amorphous silicon film for light with a wavelength of 532 nm is about 100 nm to 1000 nm, and the film thickness is 30 nm to 20 nm.
It is possible to sufficiently reach the inside of the first semiconductor region formed at 0 nm. That is, it is possible to heat from the inside of the semiconductor film, and it is possible to uniformly heat almost the entire semiconductor film in the irradiation region of the laser beam. Of course,
The wavelength of the laser beam is not limited to this value, and may be determined in consideration of the absorption coefficient of the semiconductor material forming the first semiconductor region 103.

The laser beam irradiation method is as shown in FIG. 1A, in which the laser beam is irradiated from the substrate 101 side at an angle θ with respect to the normal direction of the main surface of the glass substrate. The shape on the irradiation surface of the laser beam is not particularly limited, such as an elliptical shape or a rectangular shape, but it is preferable that the shape is longer than one side of the first semiconductor region 103 divided and formed in an island shape. .

When the amorphous semiconductor film is crystallized, the contained hydrogen is released and the atoms are rearranged so that the amorphous semiconductor film is densified and the volume contracts. Therefore, at the interface between the amorphous region and the crystalline region, the lattice continuity is not ensured and distortion occurs. As shown in FIG. 1A, the first semiconductor region 1
Forming the second semiconductor region 106 forming the active layer of the TFT inside the crystallized region 03 also removes this strained region.

The heat insulating film is provided in order to prevent the first semiconductor region, which has been heated to a molten state by irradiation with the laser beam, from being rapidly cooled after the irradiation with the laser beam and the crystal grains becoming finer. It is known that a large number of crystal nuclei are generated and microcrystallized when rapidly cooled from a molten state, but this can be prevented by providing a protective film. That is, by providing the heat insulating film, it is possible to slow down the cooling rate and prolong the time for crystal growth in the solidification process after laser beam irradiation.

Crystallization is heated by a laser beam,
It is said that the process proceeds in the process of cooling and solidifying the semiconductor in a molten state. FIG. 2 schematically shows the heat propagation direction in the cooling process with and without the heat insulating film. After the semiconductor film formed on the substrate is heated by the laser beam, in the process of cooling, the heat is divided into a component propagating to the substrate side and a component propagating in the gas phase. The ratio of the former is large.

In FIG. 2A, a blocking layer 202, a first semiconductor region 203, a barrier film 204, and a substrate 201 are formed on a substrate 201.
It shows a state in which the heat insulating film 205 is formed. The white arrows in the figure indicate the heat propagation direction. The heat propagation path includes one that propagates to the substrate side and the heat retaining film side of the region where the first semiconductor region 203 is formed, and one that propagates heat from the heat retaining region 206 of the heat retaining film 205 to the first semiconductor region. Therefore, the first semiconductor region 203 is cooled from the central portion. That is, the crystallization in this case goes from the central portion of the first semiconductor region to the outside. Figure 2
(B) is the case where the heat insulating film is not formed, and in this case, the end portion of the first semiconductor region 203 in which the rate of heat propagation and loss is large cools fastest. In this case, crystallization proceeds from the end portion of the first semiconductor region toward the inside, and the grown crystal collides with the central portion to form a crystal grain boundary.

The characteristic shape of the first semiconductor region 103 shown in FIG. 1A is that a seed region 110 is provided in one corner thereof. By irradiating a laser beam from this portion, a semiconductor region having a single crystal orientation can be formed. Crystal growth occurs on the basis of a crystal initially formed in the seed region 110 or a crystal previously formed. The crystal in this seed region is called a seed crystal, but it may be a crystal that is formed accidentally or a crystal whose crystal orientation is intentionally determined by adding a catalytic element or a specific element. You may apply.

Crystallization of an amorphous semiconductor film using a catalytic element is suitable because a crystalline semiconductor film having a relatively high orientation rate can be obtained. The applicable catalytic elements are Fe, Co, Ni, Ru, Rh, Pd, Os, Ir,
One element or a plurality of elements selected from Pt, Cu and Au are used. The thickness of the amorphous semiconductor film is 30 nm to 200 nm.

Further, germanium is suitable as the specific element, and a crystalline semiconductor film having a high orientation ratio of the {101} plane can be obtained. The concentration of germanium required to exert such an action is 0.1 atom% or more and 10 atom% or less, preferably 1 atom% or less with respect to silicon as a result of the experiment.
It may be at least 5 atomic% and not more than atomic%. The metal element is added to the amorphous silicon film and heat treatment is performed to form a compound (silicide) of silicon and the metal element, and the compound is diffused to promote crystallization. Germanium added to the amorphous silicon film does not react with this compound and exists locally around it, causing local strain. This strain acts to increase the critical radius of nucleation, has the effect of reducing the nucleation density and limiting the crystal orientation.

Various forms that the seed region 110 can take will be described with reference to FIGS. 3 to 5, and the following forms are possible. Although FIG. 3 shows a process in which a crystal grows from the seed region 110, the laser beam 107 is irradiated from the seed region 110 provided at one end of the first semiconductor region 103 and melts the semiconductor toward the other end. By scanning by scanning, crystals can be grown according to the direction. At this time, the heat insulating film 105 is formed above the first semiconductor region 103 or on the surface where the laser beam 107 does not enter. The laser beam is continuously oscillated, and the continuous melting of the molten region makes it possible to grow a continuous crystal.

As shown in the figure, the heat insulating film 105 is formed so as to cover the first semiconductor region 103, and the laser beam 107 is formed.
Irradiates the first semiconductor region 103 and the heat insulating films 105 located at both ends thereof. As a result, as described with reference to FIG. 2A, crystallization does not start from the end of the first semiconductor region 103, and crystal growth depending on the crystallinity of the seed region 107 can be reliably performed. . Of course, the growing crystal will have a single crystal orientation. The crystal appearing in the seed region 110 may be an accidental one,
By adding a catalytic element such as Ni, the probability of obtaining crystals with the {101} plane oriented increases. Moreover, the probability is further increased by adding germanium.

As a shape for further enhancing the crystal selectivity in the seed region, the seed region 110 as shown in FIG.
The shape may project from the first semiconductor region 103. By setting the width of the protruding portion to 1 to 5 μm, it is possible to prevent spontaneous generation of a plurality of crystal grains.

The configuration shown in FIG. 5 is a shape suitable for forming the seed region 110 with another semiconductor 112 before the first semiconductor region 103 is formed, and the selection region 111 is the seed region 110. It is provided to select one crystal orientation that grows from and to connect to the first semiconductor region 103. The semiconductor 112 is the first semiconductor region 103.
And a crystalline semiconductor film crystallized by adding a catalytic element, or an amorphous semiconductor film in which germanium is added to silicon, is added with a catalytic element to be crystallized. A crystalline semiconductor film or the like is applied. Since these crystalline semiconductor films have a high orientation rate, if they are used as the semiconductor 112, crystalline semiconductor films having the same crystal orientation can be formed with good reproducibility.

Of course, the form of the seed region is not limited to the form shown here, and may have another form as long as the same effect can be obtained. In addition, other {10
If a seed crystal having a crystal orientation other than the 1} plane is applied, crystal growth can be performed according to the crystal orientation.

After the entire first semiconductor region 103 is crystallized by irradiation with a continuous wave laser beam in the mode shown in FIG. 1A, a gettering treatment is preferably added. The semiconductor is brought into a molten state by irradiation with the continuous wave laser beam, but the time also depends on the scanning speed of the beam. A scanning speed of approximately 10 to 100 cm / sec is applied, but it is not possible to completely prevent external contamination of impurities. Unfavorable impurities include atmospheric components such as oxygen, nitrogen and carbon, but other Fe, Ni, Cr
There are metallic impurities suspended in the components of the device and in the gas phase. The impurities are attached to the interface with the blocking layer 102, the barrier film 104, and the like that are in contact with the first semiconductor region, and serve as the first mixing path.

In the gettering process, after forming a semiconductor film which forms a strain field in contact with the first semiconductor region, heat treatment is performed to segregate impurities. As the semiconductor film forming the strain field, an amorphous semiconductor film to which phosphorus is added, an amorphous semiconductor film to which an element of Group 18 of the periodic law such as argon is added, or the like is suitable. The heating temperature is 500 to 800 ° C., and the furnace annealing furnace, the rapid thermal annealing (RTA) furnace, or the like is used. At this time, a laser beam may be irradiated to accelerate the reaction.

Thereafter, as shown in FIG. 1B, a second semiconductor region 106 to be an active layer is formed by etching. Then, as shown in FIG. 1C, the gate insulating film 10 is formed.
8 and the gate electrode 109 are formed, a source region and a drain region are formed by adding an impurity of one conductivity type to the semiconductor region, and necessary wirings are provided to form a TFT. As is clear from comparison between FIG. 1C and FIG. 1A, the channel length direction in the completed TFT and the scanning direction of the laser beam are the same direction.

In such a laser beam irradiation method, by irradiating a continuous wave laser beam,
It enables crystal growth of large grain size in the scanning direction. Of course,
It is necessary to appropriately set detailed parameters such as the scanning speed of the laser beam and the energy density. For example,
This can be realized by converging a laser beam with an output of 5 W (532 nm) to 400 μm (long side) × 20 μm (short side), scanning in the short side direction, and setting the scanning speed to 10 to 100 cm / sec. . Melting using pulsed laser-
The crystal growth rate after solidification is about 1 m / sec, and continuous crystal growth at the solid-liquid interface becomes possible by scanning the laser beam at a slower speed and gradually cooling it.
It is possible to increase the crystal grain size. The direction of scanning the laser beam is not limited to one direction,
Reciprocal scanning may be performed. Further, by providing the heat insulating film, the crystallization can be performed from the central portion of the first semiconductor region toward the outside, and the crystal grain size can be increased.

One form of the laser processing apparatus that enables such crystallization is shown as the configuration shown in FIGS. 6 and 7. A preferable aspect of the laser processing apparatus makes it possible to irradiate a laser beam to crystallize it by designating an arbitrary position on the substrate, and by irradiating the laser beam from a plurality of directions, the throughput can be improved. In particular, it is characterized in that the laser beam is superposed on the irradiation surface to remove the energy density required for laser processing and the interference of light.

FIG. 6 is a top view showing the structure of the laser processing apparatus, and FIG. 7 is a sectional view corresponding to it. In FIG. 6 and FIG. 7, common reference numerals are used for convenience of explanation.

The first optical system 401 is the laser oscillator 3
01a, lens group 302a, first galvanometer mirror 303
a, second galvanometer mirror 304a, fθ lens 305a
Made of. Here, the first galvanometer mirror 303
a, a second galvanometer mirror 304a is provided as the deflecting means.

The second optical system 402 and the third optical system 403 have the same structure, and the deflection direction of the laser beam is controlled by the rotation angles of the first galvanometer mirror and the second galvanometer mirror, and the laser beam to be processed on the mounting table 306 is processed. The object 307 is irradiated. The beam diameter can be set to an arbitrary shape by providing the lens group 302 and a slit or the like as necessary, but it may be a circular shape, an elliptical shape, or a rectangular shape having a diameter of several tens μm to several hundreds μm. The mounting table 306 is fixed, but since it can be synchronized with the scanning of the laser beam, it may be displaceable in the XYθ directions.

The laser beams applied to the semiconductor film as the object to be processed by the first to third optical systems are superposed at the irradiation positions to obtain the energy density required for laser annealing and to interfere with light. Can be removed. Since the laser beams emitted from different laser oscillators have different phases, it is possible to reduce interference by superposing them.

Although the structure in which three laser beams emitted from the first to third optical systems are superposed is shown here, the same effect is not limited to this number, and a plurality of laser beams can be used. The purpose is achieved by overlapping. The configuration of the laser processing apparatus is not limited to the configurations shown in FIGS. 6 and 7 as long as the same effect can be obtained. In addition, when the beam profile has a Gaussian distribution, the peak positions are slightly shifted and overlapped, so that the beam profile after the superposition can be made uniform.

As another configuration of the laser processing apparatus, the apparatus having the configuration shown in FIG. 8 can be applied. Figure 8
Laser oscillator 801, high conversion mirrors 802-80
4 is a front view and a side view showing the configuration of a laser processing apparatus including an optical system 805 for forming an elliptical beam and a mounting table 808. An example of the elliptical beam forming optical system 805 is a combination of a cylindrical lens 806 and a convex lens 807. The cylindrical lens 806 makes the beam shape elliptical and the convex lens 807 is provided to collect light. Thus, by making the laser beam elliptical, the irradiation area can be widened and the processing speed can be improved.

Also, in this apparatus, the substrate 809 is moved by moving the mounting table 808 as a moving means in two axial directions.
Laser annealing is possible. For movement in one direction, a distance longer than one side of the substrate is 10 to 80 cm.
It is possible to move continuously at a constant speed of / sec,
To the other side, it is possible to discontinuously stepwise move the same extent as the elliptical beam in the longitudinal direction. The oscillation of the laser oscillator 801 and the mounting table 808 are operated in synchronization with each other by the control means 810 equipped with a microprocessor. In addition, by setting the incident angle of the laser beam to a specific angle, the laser beam (return light) reflected by the substrate 809 is prevented from entering the optical system again.

On the other hand, FIG. 9 shows an example of a mode in which the mounting table 814 is fixed and the laser beam is scanned on the surface of the substrate 809. The laser oscillation device 801 and the high conversion mirror 80 are shown.
2, 803, an elliptical beam forming optical system 811, a pair of XY scannable galvano mirrors 812, and an fθ lens 8.
The structure of the laser processing apparatus which consists of 13 is shown by a front view and a side view. An example of the elliptical beam forming optical system 811 is a combination of a concave lens and a convex lens. Thus, by making the laser beam elliptical, the irradiation area can be widened and the processing speed can be improved.
The deflection direction is controlled by the rotation angle of the galvanometer mirror, and the laser beam can be irradiated to an arbitrary position on the substrate 809 on the mounting table 814. The oscillation of the laser oscillation device 801 and the pair of galvano mirrors 812 are operated in synchronization with each other by the control means 810 equipped with a microprocessor. Further, the isolator 815 is designed so that the laser beam (return light) reflected on the irradiation surface does not re-enter the laser oscillator and damages the optical system.

By using the laser processing apparatus having the above-described structure and substantially matching the scanning direction of the laser beam and the channel length direction in the TFT as described with reference to FIG. 1, the crystal orientation becomes a single orientation. The field effect mobility can be improved. Further, by providing a seed region in which a seed crystal with a controlled crystal plane is formed, it is possible to form a single-oriented active layer, and in a top gate type TFT, a gate insulating film formed on the active layer. The quality of the film does not vary, and it is possible to reduce the variation in the threshold voltage. Of course, the present invention is a bottom gate type (or also called an inverted stagger type) TF.
It can also be applied to T.

[0068]

EXAMPLES Specific examples of a method for manufacturing a semiconductor device according to the present invention will be described below in detail with reference to the drawings.

[Embodiment 1] In this embodiment, a predetermined resist pattern is formed by photo-etching an amorphous silicon film formed on a substrate, and etching treatment is performed to form a first semiconductor region. A barrier film and a heat insulating film are formed so as to cover them, and then a continuous wave laser beam is irradiated from the substrate side to form a first film.
The semiconductor region is crystallized.

In FIG. 10, a barrier film 402 of a 100 nm silicon oxynitride film is formed on a glass substrate 401 made of aluminosilicate glass. The first semiconductor region 403 thereabove is an amorphous silicon film having a thickness of 100 nm formed by the plasma CVD method. A silicon oxide film is formed on the first semiconductor region 403 so as to cover the upper surface and the side surface of the first semiconductor region 403.
200 nm thick barrier film 404
An amorphous silicon film having a thickness of 5 is formed as a heat insulating film 405. In FIG. 10, (A) shows the first semiconductor region 403.
FIG. 3B is a top view of FIG. 1B, and FIG. Although not embodied at this stage, it is premised that the second semiconductor regions 407a and 407b forming the active layer of the TFT are formed inside the first semiconductor region 403, which does not reach the end of the first semiconductor region 403, as shown by the dotted line.

The seed region 406 is the first semiconductor region 40.
By forming a laser beam from one end of the first semiconductor region 403 in the longitudinal direction and scanning the laser beam from this region, the crystal face developed in the seed region 406 can be used as the crystal face of the first semiconductor region 403.

FIG. 11 is a diagram showing a stage of crystallization by a continuous wave laser beam. The irradiation area of the laser beam 409 may be smaller than the area of the first semiconductor region 403, but irradiation is performed so that the longitudinal direction thereof intersects with the lateral direction of the first semiconductor region 403. In this case, it is not always necessary to make them orthogonal, and they may intersect at an angle of about 30 to 90 degrees.

The beam shape can be any shape such as rectangular, linear, elliptical, etc., but in any case, irradiation is performed as shown in FIG. 11 so that crystallization is performed from one end to the other end of the first semiconductor region 403. To grow towards. For such irradiation with the laser beam 409, any structure of the laser processing apparatus shown in FIGS. 6 to 9 can be applied. In any case, the laser beam condensed by the optical system is applied to the first semiconductor region 403 and the heat insulating films 405 on both sides thereof.
To irradiate. The heat insulating film is useful for preventing the first semiconductor region heated by the irradiation of the laser beam until it reaches a molten state from being rapidly cooled after the irradiation of the laser beam to prevent crystallization from progressing from both ends.

Thus, the crystal grows from the seed region 406 irradiated with the laser beam 409, and the crystallized first semiconductor 408 is formed.

Thereafter, as shown in FIGS. 12A and 12B, the heat insulating film 405 is removed by dry etching using nitrogen trifluoride (NF ₃ ) or sulfur hexafluoride (SF ₆ ). The first semiconductor region 408 can be selectively left by removing the barrier film 404 with an aqueous solution containing hydrofluoric acid. Further, as shown in FIG. 12, the crystallized first semiconductor region 408 is etched to form a second
The semiconductor regions 407a and 407b are formed. To form a top gate type TFT, the second semiconductor regions 407a and 407a
A TFT can be formed by forming a gate insulating film, a gate electrode, and an impurity region of one conductivity type on 7b. After that, a wiring, an interlayer insulating film, or the like may be formed as needed.

The drive circuit integrated active matrix type display device using TFTs can be seen by dividing the configuration into a pixel portion and a drive circuit portion due to its functional division. A TFT using the second semiconductor region formed in this embodiment as an active layer
Then, it is possible to form them simultaneously on the same substrate.

FIG. 14 shows the relationship between the TFT substrate and the laser beam irradiation direction in detail. The TFT substrate 1201 has a pixel portion 1202, drive circuit portions 1203, 1
The area where 204 is formed is shown by a dotted line. The first semiconductor region is formed in each region, and the scanning method of the laser beam in this state is shown in enlarged views 1304, 1305, and 1306 in FIG.

For example, the drive circuit portion 1203 is a region for forming a scanning line drive circuit, and the partially enlarged view 1305 has a first semiconductor region 1251 including a second semiconductor region 1258 (shown by a dotted line) formed therein. There is. The arrangement of the first semiconductor region 1251 enables the continuous wave laser beam 1405 to scan in the direction indicated by the arrow. The second semiconductor region 1258 may have any shape, but in any case, the channel length direction and the laser beam scanning direction are aligned in the same direction.

The drive circuit section 1204 arranged in the direction intersecting with the drive circuit section 1203 is a region for forming a data line drive circuit, and the first semiconductor region 1250 including the second semiconductor region 1257 is formed. There is. The scanning direction of the laser beam 1404 is matched with the channel length direction of the channel portion formed in the second semiconductor region 1257 (enlarged view 1304). The same applies to the pixel portion 1202 and, as shown in an enlarged view 1306, the first semiconductor region 12
52 is formed, and the channel length direction of the channel portion formed in the second semiconductor region 1259 formed from the same is aligned with the scanning direction of the laser beam 1406. With this arrangement, all the laser beams have to scan in the same direction, so that the processing time can be further shortened.

As described above, by forming a heat insulating film on the first semiconductor region and irradiating it with a continuous wave laser beam, it is possible to grow crystals in which the crystal grains extend in the scanning direction of the laser beam with a single orientation. . Of course, it is necessary to appropriately set detailed parameters such as the scanning speed of the laser beam and the energy density.
It can be realized by setting cm / sec.
It is said that the crystal growth rate after melting and solidification using a pulsed laser is 1 m / sec, but the laser beam is scanned at a slower speed than that to continuously cool the solid-liquid interface by slow cooling. It is possible to grow, and it is possible to increase the crystal grain size.

[Second Embodiment] The laser beam scanning of the first embodiment is not limited to scanning in one direction, but may be reciprocal scanning.
FIG. 13 shows the mode, in which case the seed region 40 is used.
6a and 406b may be provided at both ends of the first semiconductor region 403. In the case of reciprocating scanning, it is possible to change the laser energy density for each scanning and to grow crystals in stages. Further, it is also possible to combine the process of hydrogen discharge, which is often necessary when crystallizing the amorphous silicon film, and first scan at low energy density to release hydrogen and then increase the energy density to 2 Crystallization may be completed by the second scan. With such a manufacturing method, a crystalline semiconductor film in which crystal grains extend in the laser beam scanning direction can be similarly obtained.

[Embodiment 3] In this embodiment, an amorphous silicon film formed on a substrate is crystallized in advance and the crystal grain size is increased by a continuous wave laser beam.

As shown in FIG. 15A, a blocking layer 502 and an amorphous silicon film 503 are formed on a glass substrate 501 as in the first embodiment. A mask insulating film 50 is formed thereon.
4, a 100 nm silicon oxide film is formed by a plasma CVD method, and an opening 505 is provided. Then, in order to add Ni as a catalyst element, an aqueous solution of nickel acetate of 5 ppm is spin-coated. Ni contacts the amorphous silicon film at the opening 505. The opening 505 is formed so as to be located in the seed region of the first semiconductor region which will be formed later or outside thereof.

After that, as shown in FIG.
The amorphous silicon film is crystallized by heat treatment at 4 ° C. for 4 hours. Crystallization grows in a direction parallel to the substrate surface through the opening 505 due to the action of the catalytic element. The crystalline silicon film 507 thus formed is composed of aggregated rod-shaped or needle-shaped crystals, and the respective crystals are macroscopically grown with a certain specific direction, so that the crystallinity is uniform. Also,
It is characterized by a high orientation ratio in a specific orientation.

When the heat treatment is completed, a mask insulating film 504 is formed.
Is removed by etching to obtain a crystalline silicon film 507 as shown in FIG.

After that, as shown in FIG. 16, the crystalline silicon film 507 is etched into a predetermined pattern by photolithography to form a first semiconductor region 508. After that, a barrier film 509 is formed of 20 nm of silicon oxide, and a heat insulating film 510 is formed by 2
It is formed of a 50 nm amorphous silicon film. A region where the second semiconductor regions 511a and 511b, which are active layers of the TFT, are to be formed is located inside the first semiconductor region 508, and Nd: Y
A VO ₄ laser oscillator is used to irradiate a continuously oscillating second harmonic (532 nm) from the substrate side. As shown in FIG. 16, the continuous wave laser beam 512 scans in one direction. Alternatively, reciprocal scanning is performed.

The crystalline silicon film is melted and recrystallized by the irradiation of such a laser beam. Along with this recrystallization, crystal growth in which crystal grains extend in the scanning direction of the laser beam is performed. In this case, since a crystalline silicon film having crystal planes aligned in advance is formed, it is possible to prevent precipitation of crystals and dislocations on different planes. After that, the TFT can be formed by the same process as in the first embodiment.

[Embodiment 4] Similar to Embodiment 3, after forming the glass substrate 501, the blocking layer 502, and the amorphous silicon film 503, Ni is added to the entire surface as a catalytic element. N
The method of adding i is not limited, and a spin coating method, a vapor deposition method, a sputtering method, or the like can be applied. In the case of using the spin coating method, an aqueous solution of nickel acetate of 5 ppm is applied to form the catalyst element containing layer 506 (FIG. 17A).

Thereafter, the amorphous silicon film 503 is crystallized by heat treatment at 580 ° C. for 4 hours. Thus, FIG.
As shown in (B), a crystalline silicon film 507 can be obtained. Similarly, this crystalline silicon film 507 is also formed by aggregating rod-shaped or needle-shaped crystals, and each of the crystals is macroscopically grown with a certain specific direction, so that the crystallinity is uniform. Further, there is a feature that the orientation ratio of the specific orientation is high. After that, the same process as in the third embodiment may be performed.

[Example 5] In Example 3 or Example 4
Then, after forming the first semiconductor region 508, 10¹⁹
/cm³Gettering treatment of catalyst elements remaining at the above concentrations
You may add the process of removing by. As shown in Figure 18
Then, the barrier layer on the first semiconductor region 508 is left to remain.
Argon is used as a gettering site 514 on it.
Is 1 × 10 ²⁰/cm³~ 1 x 10^{twenty one}/cm³Added amorphous silicon
Form a film.

After that, a furnace annealing furnace is used for 60.
Heat treatment at 0 ° C for 12 hours, or lamp annealing or gas heating annealing at 650 to 750 ° C, 30 to 60
N added as a catalytic element by heat treatment for
i can be segregated at the gettering site 514. By this treatment, the concentration of the catalytic element in the crystalline silicon film 507 can be made 10 ¹⁷ / cm ³ or less.

After that, the gettering site 514 is selectively removed. In this step, the barrier film 509 can be used as an etching stopper when the heat retaining film and the gettering site are selectively removed. After the gettering process is completed, the process may be performed in the same manner as in Example 3 or 4.

[Example 6] By forming a crystalline semiconductor film having a predetermined crystal orientation in the seed region, the crystal orientation can be aligned with the first semiconductor region. First, FIG.
As shown in (A), a blocking layer 602 is formed on a glass substrate 601, and an amorphous silicon film 603 is formed thereon. The amorphous silicon film 603 does not need to be too thick for the purpose of crystallizing and forming a seed region.
It is formed with a thickness of about 100 nm. After that, the catalyst element containing layer 604 is formed. This forming method may be performed in the same manner as the third or fourth embodiment.

After that, it is crystallized by heat treatment to obtain a crystalline silicon film 605. At this stage, the gettering process may be performed as in the fifth embodiment. This crystalline silicon film 605 is etched into a predetermined pattern by photolithography to form a seed crystal 606 located in the seed region as shown in FIG. 19C. Then, an amorphous semi-silicon film 607 is formed on the entire surface of the glass substrate 601 with a thickness of 150 nm.

Then, as shown in FIG. 20, the amorphous silicon film 607 is etched into a predetermined pattern by photolithography to form a first semiconductor region 608. First semiconductor region 6
At 08, a seed region 609 is formed at the end, and a seed crystal 606 is overlapped and provided in this region. The regions forming the second semiconductor regions 612a and 612b, which are indicated by the dotted lines, are arranged inside the first semiconductor region 608. A barrier film 610 and a heat retaining film 611 are formed on the first semiconductor region 608.

Then, as shown in FIG. 21, a continuous wave laser beam 61 is directed from one end of the first semiconductor region toward the other end.
Scan 3 to crystallize. Continuous wave laser beam 6
By scanning 13 from the seed region 609, the crystallization region 614 to be formed can be formed to have the same crystal orientation as the seed crystal 606. The heat insulating film can prevent the first semiconductor region, which has been heated by irradiation with the laser beam until it reaches a molten state, from being rapidly cooled after the irradiation with the laser beam so that crystallization is newly advanced from both ends.

Then, as shown in FIG. 22, the crystallized first semiconductor region 608 is etched into a predetermined pattern in which the second semiconductor regions 612a and 612b are to be formed by photolithography. To make a top gate type TFT,
A gate insulating film on the second semiconductor regions 612a and 612b,
A TFT can be formed by forming a gate electrode and an impurity region of one conductivity type. After that, a wiring, an interlayer insulating film, or the like may be formed as needed.

Example 7 In Example 6, seed crystal 60 was used.
6 may be formed of a crystalline silicon film containing germanium. This is replaced by an amorphous silicon film in FIG.
By forming an amorphous silicon film containing germanium at a ratio of atomic% to 5 atomic%, other processes may be performed in the same manner.

The advantage of using the crystalline silicon film containing germanium lies in the high orientation rate, and the orientation rate of the {101} plane can be increased to 40 to 90%. By forming a seed crystal with such a crystalline silicon film, the orientation ratio of the first semiconductor region can be increased.

[Embodiment 8] According to any of Embodiments 1 to 7, the gettering treatment described in Embodiment 5 is performed on the first semiconductor region crystallized by the continuous wave laser beam. You can The gettering method may be performed in the same manner as in the fifth embodiment. By performing the gettering treatment, the metal impurities mixed and segregated during crystallization can be removed.

[Embodiment 9] In this embodiment, a CM is manufactured by using the second semiconductor regions manufactured in Embodiments 1 to 8.
An example of manufacturing an OS type TFT will be described with reference to FIGS.

FIG. 23A shows a state in which a glass substrate 701, a blocking layer 702 are formed, and second semiconductor regions 703a and 703b serving as active layers, a gate insulating film 704, and gate electrodes 705a and 705b are formed. Shows. The gate insulating film 704 is formed by a plasma CVD method,
A silicon oxynitride film is formed on SiH ₄ and N ₂ O using O ₂ as a reaction gas to have a thickness of 80 nm. Second semiconductor region 703
Since a and 703b have a high crystal orientation ratio, it is possible to reduce variations in the film quality of the gate insulating film formed thereon, and thus variations in the threshold voltage of the TFT. Also, the gate electrodes 705a and 705a
As a material for forming 05b, Al, Ta, Ti,
Applying conductive materials such as W and Mo or their alloys,
It is formed to a thickness of 400 nm. Alternatively, Al may be used as a gate electrode, and an oxide film may be formed on the surface thereof by anodic oxidation to stabilize it.

FIG. 23B shows the formation of impurity regions.
A source or drain region 706, an LDD region 707 for the n-channel TFT is formed by an ion doping method.
And a source or drain region 708 for the p-channel TFT is formed.

By the ion doping, the crystallinity of the region implanted with the impurity element is destroyed and the region becomes amorphous. Laser treatment is performed in order to recover crystallinity and reduce resistance due to activation of impurity elements. Laser processing can be performed by the laser processing apparatus of the present invention. Also,
Laser irradiation may be performed in a hydrogen atmosphere (reducing atmosphere) to perform hydrogenation.

After that, as shown in FIG. 23C, a first interlayer insulating film 710 is formed of a silicon nitride film or a silicon oxide film. Further, the second interlayer insulating film 711 is formed using an organic resin material or a low dielectric constant material having a dielectric constant of 4 or less. As the organic resin material, acrylic, polyimide or the like can be applied. Low dielectric constant materials include SiOF and poly-a
Rylethers, BCB (benzocyclobutene), fluorinated polyimide, a-CF and the like can be applied. Next, a contact hole reaching the impurity region of each semiconductor layer is formed, and a wiring 713 is formed using Al, Ti, Ta, or the like.
714 is formed. Further, a passivation film 715 is formed with a silicon nitride film.

Thus, the n-channel TFT 750 and the p-channel TFT 760 can be formed. Although each TFT is shown here as a single unit, not only a CMOS circuit but also a single channel type NMOS circuit or PMOS circuit can be formed using these TFTs. In the second semiconductor region formed by the present invention, crystal growth is performed in parallel with the channel length direction, so that there is substantially no crystal grain boundary across which carriers can be obtained, and high field effect mobility can be obtained. The TFT manufactured in this manner can be used as a TFT for manufacturing an active matrix liquid crystal display device or a display device using a light-emitting element, or as a TFT for forming a memory or a microprocessor on a glass substrate. it can.

[Embodiment 10] A configuration example of a TFT substrate (substrate on which TFTs are formed) for realizing an active matrix drive type display device using TFTs manufactured in the same manner as in Embodiment 9 is shown in FIG. It will be described with reference to FIG. In FIG. 24, an n-channel TFT 801 and a p-channel TFT 8 are shown.
02, drive circuit section 8 having n-channel TFT 803
06, a pixel portion 807 having an n-channel TFT 804 and a capacitor 805 is formed on the same substrate. Further, FIG. 25 shows a top view thereof,
The cross-sectional structure according to BB ′ corresponds to the vertical cross-sectional view of the pixel portion 807 illustrated in FIG.

The n-channel TFT 8 of the drive circuit unit 806
Reference numeral 01 is a structure in which the LDD region overlapping the gate electrode is provided in the n-channel TFT 750 described in FIG. 23C in Embodiment 9, and has a structure that suppresses deterioration due to the hot carrier effect. Similarly, the p-channel TFT 802 has the same form as the p-channel TFT 760 and has a single drain structure. Such an n-channel TFT and a p-channel T
A shift register circuit, a buffer circuit, a level shifter circuit, a latch circuit, and the like can be formed by FT.
The n-channel TFT 803 has an LDD structure similar to that of the n-channel TFT 750 shown in FIG.
A structure suitable for a sampling circuit with reduced off-current is applied.

The second semiconductor region in which the impurity regions such as the channel formation region and the LDD region in these TFTs are formed has the second semiconductor region formed by appropriately combining the methods shown in the first to eighth embodiments. It is what is done. Since the second semiconductor region is crystal-grown in the channel length direction (or in the direction parallel to the substrate and in the channel length direction), the probability that carriers cross the crystal grain boundary is significantly reduced. To do. Thereby, high field effect mobility can be obtained, and extremely excellent characteristics can be obtained. 814 to 816 are each T
The wiring is connected to the source or drain of the FT.

The n-channel TFT 804 of the pixel portion 807
Is a structure in which the semiconductor region 820 is formed as an active layer and the LDD structure TFTs are connected in series, and one of them is connected to the data line 810 via the connection wiring 811. The other is connected to the pixel electrode. In addition, the gate line 812
Are electrically connected to the gate electrode 824. Also,
An impurity region to which boron is added is formed in the semiconductor region 821 which functions as one electrode of the capacitor 805. The capacitor 805 is formed of a capacitor electrode 822 and a semiconductor region 821 using an insulating film 823 (the same film as the gate insulating film) as a dielectric. The semiconductor regions 820, 8
Reference numeral 21 corresponds to the second semiconductor region produced in each of Examples 1 to 8.

In these TFTs, the second semiconductor region forming the channel forming region and the impurity region has a high orientation rate and is flat, so that variations in the film quality of the gate insulating film formed thereon can be reduced. Therefore, variations in the threshold voltage of the TFT can be reduced. As a result, it is possible to drive the TFT at a low voltage, which has the advantage of reducing power consumption. Further, since the surface is flattened, the electric field is not concentrated on the convex portion, so that it is possible to suppress the deterioration caused by the hot carrier effect particularly at the drain end. In addition, the concentration distribution of carriers flowing between the source and the drain becomes high in the vicinity of the interface with the gate insulating film, but since it is smoothed, the carriers can move smoothly without being scattered, and the field effect mobility is high. Can be increased.

In order to manufacture a liquid crystal display device from such a TFT substrate, a counter substrate on which a common electrode is formed is used.
The alignment film and the liquid crystal layer may be formed at intervals of about 8 μm. Known techniques can be applied to these.

FIG. 26 shows a circuit configuration of such an active matrix substrate. TFT9 of the pixel portion 901
The drive circuit unit for driving 00 is a data line drive circuit 902,
The scan line driver circuit 902 includes a shift register circuit, a buffer circuit, a level shifter circuit, a latch circuit, and the like as needed. In this case, the scanning line drive circuit 9
Reference numeral 02 denotes a video signal, and the controller 9
04 video signal and timing generator 907
The scanning line driving circuit timing signal from is input.
The data line drive circuit 902 includes a timing generator 9
The data line driving circuit timing signal from 07 is input and the signal is output to the scanning line. Microprocessor 90
Reference numeral 6 controls the controller 904, writes data such as a video signal to the memory 905, inputs and outputs from the external interface 908, and manages the operation of the entire system.

The TFT for forming these circuits can be formed by the TFT having the structure shown in this embodiment. By making the second semiconductor region forming the channel formation region of the TFT substantially a single crystal region, the characteristics of the TFT can be improved and various functional circuits can be formed over a substrate such as glass.

[Embodiment 11] As another embodiment using a TFT substrate, an example of a display device using a light emitting element will be described with reference to the drawings. FIG. 27 is a sectional view showing a pixel structure of a display device formed by disposing a TFT for each pixel.
The n-channel TF shown in FIGS.
T2100, 2102 and p-channel TFT 2101
Has the same configuration as that of the ninth embodiment, and detailed description thereof will be omitted in the present embodiment.

FIG. 27A shows a structure in which an n-channel TFT 2100 and a p-channel TFT 2101 are formed in a pixel over a substrate 2001 with a blocking layer 2002 interposed therebetween. In this case, the n-channel TFT 2100 is a switching TFT, and the p-channel TFT 21
Reference numeral 01 is a current control TFT, the drain side of which is connected to one electrode of the light emitting element 2105. The p-channel TFT 2101 is intended for the operation of controlling the current flowing through the light emitting element. Of course, the number of TFTs provided in one pixel is not limited, and an appropriate circuit configuration can be adopted according to the driving method of the display device.

The light emitting element 2105 shown in FIG.
An anode layer 2011, an organic compound layer 2012 including a light emitting body,
The cathode layer 2013 is formed, and the passivation layer 2014 is formed thereon. The organic compound layer is a light emitting layer,
A hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, etc. are included. In addition, luminescence in an organic compound includes light emission when returning from a singlet excited state to a ground state (fluorescence) and light emission when returning from a triplet excited state to a ground state (phosphorescence). Or it includes both luminescence.

A material having a high work function such as indium oxide, tin oxide or zinc oxide is used as a material for forming the anode, and MgAg, AlMg, Ca, Mg, Li or AlL is used for the cathode.
i, an alkali metal or an alkaline earth metal such as AlLiAg, typically a material having a low work function formed of a magnesium compound is used. Further, the cathode may be formed by a combination of a thin lithium fluoride layer having a thickness of 1 to 20 nm and an Al layer, or a combination of a thin cesium layer and an Al layer. The anode is connected to the wiring 2010 on the drain side of the p-channel TFT 2101, and a partition layer 2003 is formed so as to cover the end of the anode 2011.

A passivation film 2014 is formed on the light emitting element 2105. Passivation layer 20
14 is formed using a material having a high barrier property against oxygen and water vapor, such as silicon nitride, silicon oxynitride, and diamond-like carbon (DLC). With such a structure, the light emitted from the light emitting element is radiated from the anode side.

On the other hand, FIG. 27B shows the n-channel TFT 21 on the substrate 2001 with the blocking layer 2002 interposed therebetween.
00 and n-channel TFT 2102 are formed in the pixel. In this case, the n-channel TFT 21
00 is a switching TFT, which is an n-channel TF
T2102 is a current control TFT, and its drain side is connected to one electrode of the light emitting element 2106.

The light emitting element 2106 is an n-channel TFT.
A film 2016 made of a material having a high work function such as indium oxide, tin oxide, or zinc oxide is formed as an anode material over the wiring 2015 connected to the drain side of the 2102. An organic compound layer 2018 is formed on this.

The cathode is composed of a first cathode layer 2019 formed of a material having a low work function of 1 to 2 nm and a first cathode layer 20.
19 and a second cathode layer 2017 provided to reduce the resistance of the cathode. First cathode layer 201
9 is MgAg, AlMg, Ca, Mg, Li, AlL in addition to cesium, an alloy of cesium and silver, and lithium fluoride.
i, an alkali metal such as AlLiAg or an alkaline earth metal, typically a magnesium compound. The second cathode layer 2017 is formed of a metal material such as Al and Ag having a thickness of 10 to 20 nm or a transparent conductive film such as indium oxide, tin oxide and zinc oxide having a thickness of 10 to 100 nm. A passivation film 2020 is formed over the light emitting element 2106. With this structure, the light emitted from the light emitting element is emitted from the cathode side.

In addition, the light emitting element 21 in FIG.
As another mode of 06, on the wiring 2015 connected to the drain side of the n-channel TFT 2102, as a cathode material, cesium, an alloy of cesium and silver, lithium fluoride, MgAg, AlMg, Ca, Mg, Li, AlLi, A
Alkali metal or alkaline earth metal such as LiAg,
Cathode layer 201 typically made of a magnesium compound
6, organic compound layer 2018, first anode layer 2019 having a thin thickness of about 1 to 2 nm, second anode layer 20 formed of a transparent conductive film
It is also possible to adopt a configuration of 17. The first anode layer is formed of a material having a high work function, such as nickel, platinum, or lead, by a vacuum vapor deposition method.

As described above, a display device using an active matrix driven light emitting element can be manufactured. In these TFTs, the second semiconductor region forming the channel forming region and the impurity region has a high orientation rate and is flat, so that variation in the film quality of the gate insulating film formed thereon can be reduced. Therefore, variations in the threshold voltage of the TFT can be reduced. As a result, it is possible to drive the TFT at a low voltage, which has the advantage of reducing power consumption. In this display device, a TFT for controlling a current connected to the light emitting element is required to have a high current driving ability, and thus it is suitable for the application. Although not shown here, the structure in which the driver circuit portion is provided around the pixel portion may be similar to that in Embodiment 10.

[Embodiment 12] The present invention can be applied to various semiconductor devices. Examples of such semiconductor devices include personal digital assistants (electronic notebooks, mobile computers, mobile phones, etc.), video cameras, digital cameras, personal computers, television receivers, projection display devices, and the like. Examples of those are shown in FIGS.

FIG. 28A shows an example in which the present invention is applied to complete a television receiver, which includes a housing 3001 and a support base 3.
002, a display unit 3003, and the like. The TFT substrate manufactured according to the present invention is applied to the display portion 3003, and the television receiver can be completed according to the present invention.

FIG. 28B shows an example in which the present invention is applied to complete a video camera. The main body 3011 and the display unit 3 are shown.
012, voice input unit 3013, operation switch 3014,
The battery 3015 and the image receiving unit 3016 are included. The TFT substrate manufactured by the present invention is the display unit 3.
012, and the present invention can complete a video camera.

FIG. 28C shows an example in which a notebook personal computer is completed by applying the present invention, which is composed of a main body 3021, a housing 3022, a display portion 3023, a keyboard 3024, and the like. The TFT substrate manufactured according to the present invention is applied to the display portion 3023, and a personal computer can be completed according to the present invention.

FIG. 28D shows the PDA (P
personal digital assistant)
Body 3031, stylus 3032, display portion 3033,
The operation button 3034 and the external interface 3035 are included. TFT manufactured by the present invention
The substrate is applied to the display unit 3033, and according to the present invention, a PDA
Can be completed.

FIG. 28 (E) is an example in which the present invention is applied to complete a sound reproducing device, specifically, a vehicle-mounted audio device, which is a main body 3041, a display portion 3042, operation switches 3043, 3044. Etc. The TFT substrate manufactured according to the present invention has a display portion 304.
2 and can complete an audio device according to the present invention.

FIG. 28F shows an example in which the present invention is applied to complete a digital camera. The main body 3051 and the display portion are shown.
(A) 3052, eyepiece 3053, operation switch 305
4, a display unit (B) 3055, a battery 3056, and the like. The TFT substrate manufactured according to the present invention is applied to the display portion (A) 3052 and the display portion (B) 3055, and the digital camera can be completed by the present invention.

FIG. 28G shows an example in which a mobile phone is completed by applying the present invention. The main body 3061 and the voice output unit 3 are shown.
062, a voice input unit 3063, a display unit 3064, operation switches 3065, an antenna 3066, and the like. The TFT substrate manufactured according to the present invention has a display unit 30.
It is applied to 64 and can complete a mobile phone according to the present invention.

FIG. 29A shows a front type projector including a projection device 2601, a screen 2602 and the like. FIG. 29B illustrates a rear type projector including a main body 2701, a projection device 2702, a mirror 2703, a screen 2704, and the like.

Note that FIG. 29C is a diagram showing an example of the structure of the projection devices 2601 and 2702 in FIGS. 29A and 29B. Projection device 2601, 270
2 is a light source optical system 2801 and mirrors 2802 and 2804.
2806, dichroic mirror 2803, prism 2807, liquid crystal display device 2808, retardation plate 2809,
The projection optical system 2810 is used. Projection optical system 2810
Is composed of an optical system including a projection lens. Although the present embodiment shows an example of a three-plate type, it is not particularly limited and may be, for example, a single-plate type. In addition, the practitioner appropriately uses an optical lens, a film having a polarization function, a film for adjusting the phase difference, in the optical path indicated by the arrow in FIG.
An optical system such as an IR film may be provided.

FIG. 29D is a diagram showing an example of the structure of the light source optical system 2801 in FIG. 29C. In this embodiment, the light source optical system 2801 includes a reflector 2811, a light source 2812, a lens array 2813, and a lens array 2813.
814, a polarization conversion element 2815, and a condenser lens 2816. Note that the light source optical system shown in FIG. 29D is an example and is not particularly limited. For example, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting a phase difference, and an IR film in the light source optical system.

FIG. 30 shows an electronic book including a main body 3101,
Display unit A3102, display unit B3103, storage medium 310
4, an operation switch 3105, an antenna 3106 and the like. An electronic ink display can be applied to the display portion B3103, and the TFT substrate manufactured according to the present invention includes a display portion A3102 and a display portion B310.
It is possible to form the driving circuit and the pixel portion of No. 3,
According to the present invention, an electronic book can be completed.

It should be noted that the electronic device illustrated here is only an example and the present invention is not limited to these applications.

[0138]

As described above, according to the present invention,
By forming the first semiconductor region and making the scanning direction of the continuous wave laser beam and the channel length direction in the TFT the same direction, the crystal orientation becomes a single orientation, and the field effect mobility can be improved. Further, by providing a seed crystal with a controlled crystal plane in the seed region, it becomes possible to form a second semiconductor region having a single orientation, and in a top gate type TFT, a gate insulating film formed on the second semiconductor region can be formed. It is possible to prevent variations in film quality and reduce variations in threshold voltage.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a concept of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a diagram illustrating details of a crystallization process according to the present invention.

FIG. 3 is a diagram for explaining the details of a crystallization step according to the present invention.

FIG. 4 is a diagram illustrating details of a crystallization process according to the present invention.

FIG. 5 is a diagram illustrating details of a crystallization process according to the present invention.

FIG. 6 is a layout view (top view) showing one embodiment of a laser irradiation apparatus applied to the present invention.

FIG. 7 is a layout view (side view) showing one embodiment of a laser irradiation apparatus applied to the present invention.

FIG. 8 is a layout view showing one embodiment of a laser irradiation apparatus applied to the present invention.

FIG. 9 is a layout view showing one embodiment of a laser irradiation apparatus applied to the present invention.

FIG. 10 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 11 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 12 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 13 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 14 is a diagram illustrating a relationship between a structure of a TFT substrate, an arrangement of semiconductor regions forming a TFT, and a scanning direction of a laser beam.

FIG. 15 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 16 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 17 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 18 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 19 is a diagram for explaining an example of a crystallization step according to the present invention.

FIG. 20 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 21 is a diagram illustrating an example of a crystallization step according to the present invention.

FIG. 22 is a diagram for explaining an example of a crystallization step according to the present invention.

FIG. 23 is a cross-sectional view illustrating a manufacturing process of a TFT having a CMOS structure.

FIG. 24 is a cross-sectional view showing the structure of a TFT substrate.

FIG. 25 is a top view showing the structure of the TFT substrate.

FIG. 26 is a block diagram showing an example of a circuit configuration of a TFT substrate.

FIG. 27 is a cross-sectional view showing a structure of a pixel of a semiconductor device provided with a light emitting element.

FIG. 28 illustrates an example of a semiconductor device.

FIG. 29 illustrates an example of a semiconductor device.

FIG. 30 illustrates an example of a semiconductor device.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/336 H01L 29/78 627G 29/786 627Z F term (reference) 2H092 JA24 JA25 JA34 JA37 JA41 KA04 KA05 MA30 NA05 NA22 NA29 5F052 AA02 AA17 BA02 BA07 BA11 BA15 BA18 BB01 BB04 BB07 CA04 CA10 DA02 DA03 DA10 DB03 EA02 EA04 EA15 EA16 FA03 FA06 FA19 JA02 JA04 5F110 AA01 BB02 EE25 FF02 EE02 FF02 EE02 FF02 EE02 FF02 EE02 EE02 FF02 EE02 EE04 EE04 EE02 FF03 EE02 EE02 EE02 HJ23 HL03 HL04 HM15 NN03 NN22 NN23 NN24 NN27 NN73 PP03 PP04 PP05 PP07 PP24 PP29 PP34 PP35 PP36 PP40 QQ24 QQ28

Claims (11)

[Claims] 1. A first semiconductor region is formed on a substrate, a barrier film is formed to cover the first semiconductor region, and a heat insulating film is formed to cover an upper surface and a side surface of the first semiconductor region through the barrier film. Then, through the substrate, a continuous wave laser beam is scanned from one end to the other end of the first semiconductor region to crystallize the first semiconductor region, and after removing the heat retaining film and the barrier film, A method for manufacturing a semiconductor device, wherein the first semiconductor region is etched to form a second semiconductor region such that a scanning direction of the laser beam and a channel length direction of a thin film transistor are in the same direction. 2. A first semiconductor region is formed on a substrate, a barrier film is formed to cover the first semiconductor region, and a heat insulating film is formed to cover an upper surface and a side surface of the first semiconductor region through the barrier film. Then, a continuous wave laser beam is scanned from one end to the other end of the first semiconductor region through the substrate to crystallize the first semiconductor region, and after removing the heat insulating film, the first semiconductor region is removed. An amorphous semiconductor film is formed on one semiconductor region, a metal element is segregated in the amorphous semiconductor film by heat treatment, the amorphous semiconductor film and the barrier film are removed, and then the first semiconductor region is formed. A method for manufacturing a semiconductor device, comprising: etching to form a second semiconductor region so that a scanning direction of the laser beam and a channel length direction in a thin film transistor are the same direction. 3. A crystalline semiconductor film is formed by forming an amorphous semiconductor film on a substrate, adding a catalytic element, and then heat-treating the amorphous semiconductor film to crystallize the amorphous semiconductor film. Is etched to form a first semiconductor region, and the first semiconductor region is formed.
A barrier film is formed to cover the semiconductor region, a heat insulating film is formed to cover the upper surface and side faces of the first semiconductor region via the barrier film, and one end to the other end of the first semiconductor region is formed via the substrate. A continuous wave laser beam is scanned toward the first semiconductor region to modify the crystallinity, the heat insulating film and the barrier film are removed, and then the first semiconductor region is etched to scan the laser beam in the scanning direction. And a second semiconductor region is formed such that the channel length direction of the thin film transistor is the same direction as the channel length direction. 4. An amorphous semiconductor film is formed on a substrate, the catalyst element is selectively added thereto, and then the amorphous semiconductor film is heated from a region where the catalyst element is selectively added to the substrate. To form a crystalline semiconductor film by crystallizing in a direction parallel to the first semiconductor region, etching the crystalline semiconductor film to form a first semiconductor region, and forming a barrier film covering the first semiconductor region. A heat insulating film covering the upper surface and the side surface of the first semiconductor region is formed through the first semiconductor region, and a continuous wave laser beam is scanned from one end to the other end of the first semiconductor region through the substrate. After modifying the crystallinity of the semiconductor region and removing the heat retaining film and the barrier film, the first semiconductor region is etched so that the scanning direction of the laser beam and the channel length direction of the thin film transistor are the same direction. So The method for manufacturing a semiconductor device and forming a second semiconductor region. 5. The method according to claim 3 or 4, wherein the first
A method for manufacturing a semiconductor device, characterized in that after the crystallinity of a semiconductor region is modified, the heat insulating film is removed and a gettering treatment for removing the catalytic element is performed. 6. A first amorphous semiconductor film is formed on a substrate, a catalyst element is added, and the amorphous semiconductor film is crystallized by heat treatment to form a first crystalline semiconductor film, First
The crystalline semiconductor film is etched to form a seed crystal region, a second amorphous semiconductor film overlapping the seed crystal region is formed on the substrate, and the second amorphous semiconductor film is etched. , At least a portion of which overlaps with the seed crystal region
A semiconductor region is formed, a barrier film is formed to cover the first semiconductor region, a heat insulating film is formed to cover an upper surface and a side surface of the first semiconductor region via the barrier film, and a barrier film is formed via the substrate. In one semiconductor region, a continuous wave laser beam is scanned from one end overlapping the seed crystal region to the other end to crystallize the first semiconductor region, and after removing the heat retaining film and the barrier film, the first semiconductor region is removed. A method for manufacturing a semiconductor device, comprising: etching a semiconductor region and a seed crystal region to form a second semiconductor region so that a scanning direction of the laser beam and a channel length direction in a thin film transistor are in the same direction. 7. A first crystalline semiconductor is formed by forming a first amorphous semiconductor film containing silicon and germanium on a substrate, adding a catalytic element, and crystallizing the amorphous semiconductor film by heat treatment. Forming a film, etching the first crystalline semiconductor film to form a seed crystal region, forming a second amorphous semiconductor film on the substrate, the second amorphous semiconductor film overlapping the seed crystal region, The crystalline semiconductor film is etched to form a first semiconductor region that at least partially overlaps with the seed crystal region, the heat insulating film and the barrier film are removed, and then the first semiconductor region and the seed crystal region are etched. Then, the second semiconductor region is formed so that the scanning direction of the laser beam and the channel length direction of the thin film transistor are the same direction. 8. The method according to claim 6 or 7, wherein:
After crystallizing the semiconductor region, the heat insulating film is removed,
A method for manufacturing a semiconductor device, which comprises performing a gettering process for removing the catalyst element. 9. The method for manufacturing a semiconductor device according to claim 1, wherein the continuous wave laser beam is irradiated by superimposing a plurality of laser beams on an irradiation surface. 10. The wavelength of the continuous wave laser beam according to claim 1, wherein the continuous wave laser beam has a wavelength of 400.
nm to 700 nm, a method for manufacturing a semiconductor device. 11. A method for manufacturing a semiconductor device according to claim 1, wherein a harmonic of a continuous wave laser beam emitted from a solid-state laser oscillator is used.