JP2003158089A - Laser irradiation device, laser irradiation method and manufacturing method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for efficiently performing uniform irradiation with a laser beam even when using a highly coherent laser and a large area substrate. SOLUTION: This laser irradiation device is provided with a laser, a division means for turning the laser beam emitted from the laser into a plurality of the laser beams, a formation means for synthesizing the plurality of the laser beams on or near an irradiation plane and turning them to the laser beam having cyclic energy distribution, and a relative substrate moving means to the laser beam. By using such a laser irradiation device, the entire surface of a semiconductor film can be annealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of irradiating a laser beam (laser beam) and a laser irradiating device for performing the method (in order to guide a laser and a laser beam (laser beam) output from the laser to an object to be processed. (Including optical system)
Regarding In addition, the present invention relates to a method for manufacturing a semiconductor device which is manufactured by including irradiation with laser light in its process. Note that the semiconductor device mentioned here includes an electro-optical device such as a liquid crystal display device and a light-emitting device, and an electronic device including the electro-optical device as a component.

[0002]

2. Description of the Related Art In recent years, a technique for obtaining a crystalline semiconductor film by subjecting a semiconductor film formed on an insulating substrate such as glass to laser annealing to crystallize or improve crystallinity has been widely studied. ing. Note that in this specification, a crystalline semiconductor film refers to a semiconductor film in which a crystallized region exists and also includes a semiconductor film whose entire surface is crystallized.

The glass substrate has an advantage that it is cheaper than a synthetic quartz glass substrate and a large-area substrate can be easily manufactured. Further, the laser is preferably used for crystallization because the melting point of the glass substrate is low. The laser can give high energy to the semiconductor film without raising the temperature of the substrate so much. Further, the throughput is remarkably higher than that of the heating means using the electric heating furnace.

Since the crystalline semiconductor film formed by irradiation with laser light has a high mobility, a thin film transistor (TFT) is formed using this crystalline semiconductor film, and for example, one glass substrate is It is used for an active matrix type liquid crystal display device or the like for manufacturing TFTs for a pixel portion or for a pixel portion and a driving circuit.

As the laser light, laser light oscillated from an excimer laser or the like is often used. The excimer laser has the advantages that it has a large output and that it can be repeatedly irradiated at high frequencies, and that the laser light emitted from the excimer laser has a high absorption coefficient for a silicon film that is often used as a semiconductor film. Have advantages.
Then, for the irradiation of the laser light, the laser light is shaped by an optical system so that the shape of the irradiation surface or its vicinity becomes a rectangular shape, and the laser light is moved (or the irradiation position of the laser light is set to the irradiation surface. The method of irradiating (relatively moving relative to) is high in productivity and industrially excellent. In the present specification, a laser beam having a rectangular shape on or near the irradiation surface is called a rectangular beam, and a laser beam having a dot shape is called a point beam.

On the other hand, the area of the substrate to be used is increasing more and more. This is because when a semiconductor device such as a plurality of liquid crystal display device panels is manufactured using one large-sized substrate, throughput is higher and cost reduction can be realized. As a large area substrate, for example, a substrate having a size of 600 mm × 720 mm, a circular substrate having a size of 12 inches (a diameter of about 300 mm), or the like is used. Further, in the future, it is considered that a substrate whose one side exceeds 1 m will be used.

An excimer laser generally used for laser annealing uses K as an excitation gas for forming a laser beam.
rF (wavelength 248 nm) and XeCl (wavelength 308 nm)
Is used. However, Kr (Krypton) and Xe
A gas such as (xenon) is very expensive, and there is a problem that the production cost increases if the frequency of gas exchange increases.

Further, it is necessary to replace accessories such as a laser tube for oscillating a laser and a gas purifier for removing unnecessary compounds generated in the oscillating process once every 3 to 6 months. Many of these accessory devices are expensive, which also causes a problem of increasing the manufacturing cost.

As described above, the laser irradiation device using the excimer laser certainly has high performance, but it takes a lot of time and effort for maintenance, and the production laser device has a running cost. It also has the disadvantage of high cost.

Therefore, in recent years, it is possible to anneal the semiconductor film by using a solid-state laser whose maximum output is remarkably improved. A solid-state laser can output laser light basically if it has a solid crystal, a resonant mirror, and a light source for exciting the solid crystal, and therefore does not require maintenance like an excimer laser. That is, since the running cost is much lower than that of the excimer laser, it is possible to significantly reduce the manufacturing cost of the semiconductor device. Further, as the number of maintenances decreases, the operating rate of the mass production line also increases, so the overall throughput of the manufacturing process improves, which also greatly contributes to the reduction of the manufacturing cost of the semiconductor device. Further, the solid-state laser has a smaller occupied area than the excimer laser, which is advantageous for designing the manufacturing line.

Solid-state lasers are generally YAG lasers (usually Nd: YAG lasers), YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, glass lasers,
Ruby laser, Alexandride laser, Ti: sapphire laser, etc. are known. Here, a YAG laser will be described as an example. The YAG laser is known to emit laser light having a wavelength of 1065 nm as a fundamental wave. The absorption coefficient of the laser beam to the silicon film is very low, and if the amorphous silicon film, which is one of the silicon films, is crystallized as it is, the energy loss is large and the efficiency is poor. However, this laser light can be converted into a shorter wavelength by using a non-linear optical element. The second harmonic (532 nm), the third harmonic (355 nm), the fourth harmonic (266 nm), the fifth harmonic, depending on the wavelength to be converted.
It is named as a harmonic wave (213 nm). Since these harmonics have a higher absorption coefficient than the amorphous silicon film, they can be used for crystallization of the amorphous silicon film.

[0012]

However, the YAG
A laser is coherent light with very high coherence. Coherent length of excimer laser is several μm to several tens of μ
m, the coherent length of the YAG laser is 1
It is around 0 mm or more. Therefore, even if the laser beam is focused on the irradiation surface or in the vicinity thereof, it is difficult to form a laser beam having a uniform energy distribution due to the influence of interference, and uniform laser annealing cannot be performed.

Therefore, the present invention provides a method for efficiently irradiating a laser beam over the entire irradiation surface even when a laser having a high coherence or a large area substrate is used, and a laser for performing the method. An object is to provide an irradiation device. Another object is to provide a method for manufacturing a semiconductor device using a semiconductor film obtained by crystallizing a semiconductor film or activating an impurity element by such a laser irradiation method.

[0014]

The structure of the invention relating to the laser irradiation apparatus disclosed in the present specification is such that a laser and a laser beam (laser beam) emitted from the laser are divided into a plurality of laser beams (laser beams). Means and the plurality of laser beams (laser beams) on or near the irradiation surface
And a means for moving the substrate relative to the laser light, and a means for forming a laser light (laser beam) having a periodic energy distribution.

The configuration of the invention relating to the laser irradiation apparatus disclosed in the present specification includes a laser, a first optical system for dividing a laser beam (laser beam) emitted from the laser into a plurality of portions, and the first optical system. A laser beam (laser beam) that has a periodic energy distribution on the irradiated surface by combining the laser beams (laser beam) split by the optical system.
And a second optical system that forms the first optical system, and the first optical system is provided between the laser and the second optical system.

The configuration of the invention relating to the laser irradiation apparatus disclosed in the present specification is the laser irradiation apparatus for irradiating the surface to be irradiated with the laser beam (laser beam) emitted from the laser, the first optical system and the second optical system. And the second optical system is arranged so that the optical axis of the laser beam (laser beam) split by the first optical system is superposed on the irradiated surface. The first emitted from the laser
The laser light that has passed through the optical system and the second optical system has a periodic energy distribution on the irradiated surface.

In the structure of the above invention, the laser is
It is characterized by being a continuous wave or pulsed solid state laser. As the solid-state laser, a YAG laser,
YVO ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, Alexandride laser,
Ti: sapphire laser etc. are mentioned.

Further, in the above invention, the first
The optical system and the second optical system are characterized in that they are installed so as to obliquely irradiate the surface to be irradiated of the sample with the laser beam (laser beam) emitted from the laser.

Further, in the above-mentioned structure of the present invention, the periodic energy distribution is formed by the plurality of laser beams being combined on the irradiation surface or in the vicinity thereof and interfering with each other. However, when strong interference occurs, there is a possibility that the difference in height of the energy density becomes too large and sufficient annealing cannot be performed in the region of low energy density. Therefore, the first interference formed by at least two laser lights among the plurality of laser lights and the second interference formed by other at least two laser lights are overlapped with each other while being offset from each other. By changing the energy distribution of the second interference, the height difference of the energy density can be adjusted. That is, by combining the energy distribution of the first interference and the energy distribution of the second interference, it is possible to form a laser beam (laser beam) with a small periodic change in the energy distribution. Further, when the first interference and the second interference have the same energy distribution, it is possible to form a laser beam having a uniform energy distribution on the irradiation surface by shifting and superimposing by half a period. Of course, the number of overlapping interferences is not limited to two.

Further, in the above-mentioned configuration of the invention, the means for dividing the laser light into a plurality of laser beams (laser beams) can be carried out by using one kind selected from a cylindrical lens array, a prism and a mirror, or a plurality of kinds. By using it, it is possible to divide into more laser light (laser beam). Such means for splitting the laser light (laser beam) is used in a laser such as Gaussian, in which the distribution of the beam is higher in the center than in the periphery,
It has the effect of making the laser uniform.

In the structure of the present invention, the means for combining the plurality of laser beams (laser beams) may be performed by using a mirror or a cylindrical lens, or may be performed by using both a mirror and a cylindrical lens. You can also Note that it is preferable to use a cylindrical lens because the length of the laser light in one direction is shortened and the energy density on the irradiation surface is increased.

Further, in the configuration of the invention relating to the laser irradiation method disclosed in the present specification, the laser light (laser beam) is divided into a plurality of laser lights (laser beams), and the plurality of laser lights are irradiated on or near the irradiation surface. (Laser beam)
Are combined to form a laser beam (laser beam) having a periodic energy distribution, and the substrate is irradiated while moving the substrate relative to the laser beam (laser beam).

Further, in the configuration of the invention relating to the laser irradiation method disclosed in this specification, the optical path of the laser light (laser beam) emitted from the same laser is divided into a plurality of parts by the first optical system, and the plurality of the plurality of parts are divided into the plurality of parts. The divided laser light (laser beam) is radiated obliquely to the surface to be irradiated by the second optical system, so that the laser light (laser beam) has a periodic energy distribution on the surface to be irradiated. Combining,
Irradiation is performed on the surface to be irradiated.

Further, in the configuration of the invention relating to the laser irradiation method disclosed in the present specification, the optical path of the laser beam (laser beam) emitted from the same laser is divided into a plurality of parts by the first optical system, and the plurality of parts are divided into the plurality of parts. The divided laser light (laser beam) is obliquely applied to the irradiated surface by the second optical system, and the laser light (having a periodic energy distribution in the first direction of the irradiated surface) is generated. The laser beam) is combined and irradiated in a first direction of the surface to be irradiated and in a second direction perpendicular to the first direction.

In the structure of the above invention, the laser beam (laser beam) is oscillated from a continuous wave or pulsed solid state laser. Further, as the solid-state laser, YAG laser, YV
O ₄ laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandrite laser, T
i: Examples include sapphire laser.

Further, in the above-mentioned structure of the invention, the periodic energy distribution is formed by combining the plurality of laser beams (laser beams) at or near the irradiation surface and causing interference.

Further, in the structure of the above invention, the means for splitting into the plurality of laser beams (laser beams) may be performed by using one kind selected from a cylindrical array lens, a prism and a mirror, or a plurality of kinds. By using it, it is possible to divide into more laser beams.

Further, in the structure of the above invention, the means for synthesizing the plurality of laser beams (laser beams) may be performed by using a mirror or a cylindrical lens, or may be performed by using both the mirror and the cylindrical lens. You can also

Further, in the structure of the invention relating to the method for manufacturing a semiconductor device disclosed in this specification, a laser beam is divided into a plurality of laser beams (laser beams), and the plurality of laser beams (laser beams) are irradiated on or near the irradiation surface. Beam) to form a laser beam having a periodic energy distribution, and the laser beam (laser beam) is irradiated while moving the semiconductor film.

In the structure of the above invention, the laser light is oscillated from a continuous wave or pulsed solid-state laser. Further, as the solid-state laser, YAG laser, YVO ₄ laser, YLF laser are used.
Laser, YAlO ₃ laser, glass laser, ruby laser, alexandrite laser, Ti: sapphire laser and the like can be mentioned.

Further, in the above-mentioned structure of the invention, the periodic energy distribution is formed by the plurality of laser beams (laser beams) being combined and interfering with each other on or near the irradiation surface.

Further, in the structure of the above invention, the means for splitting into the plurality of laser beams (laser beams) may be performed by using one kind selected from a cylindrical array lens, a prism and a mirror, or a plurality of kinds. By using it, it is possible to divide into more laser light (laser beam).

In the structure of the present invention, the means for combining the plurality of laser beams (laser beams) may be performed by using a mirror or a cylindrical lens, or may be performed by using both a mirror and a cylindrical lens. You can also

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 shows an embodiment of the present invention.
~ It demonstrates in detail using FIG.

FIG. 1 shows an example of the laser irradiation apparatus of the present invention. The laser light oscillated from the laser 101 is converted into a harmonic by the nonlinear optical element 102, and split into a plurality of laser lights by the mirror 103 which is a splitting means. The respective laser lights reach the substrate 110 after being reflected by the mirrors 104a and 104b which are means for forming laser light having a periodic energy distribution. In the substrate 110, a plurality of laser beams are combined to cause interference,
Laser light having a periodic energy distribution is formed. The substrate 110 is installed on a movable stage 111 that is a means for moving the substrate relative to the laser light. By moving the stage 111, it is possible to irradiate a large area substrate with the laser light. There is. Also,
It is desirable to install the cylindrical lenses 105a and 105b in order to increase the energy density on the irradiation surface.

The shape of the laser light emitted from the laser differs depending on the type of laser, and is circular when the rod shape is cylindrical and rectangular when the rod is slab type.

Here, how the laser light interferes on the irradiation surface will be described with reference to FIG.

As shown in FIG. 2A, when a plurality of laser beams are superposed on the irradiation surface, interference occurs. At this time, the energy density distribution is a wavy periodic distribution in which high energy density portions and low energy density portions alternately appear, as shown in FIG. 2B. It can be considered that a plurality of dot-shaped laser lights form a row by paying attention to only a portion having a high energy density. When irradiation is performed using such laser light, it is possible to perform irradiation with laser light much more efficiently than in the case where there is one point laser light. This is particularly effective when the semiconductor film is annealed by using a laser beam having a high energy density emitted from a high-power laser. Further, even if a laser beam having high coherence is used, it is very effective because a periodic energy density distribution can be formed by causing interference on the irradiation surface.

Further, as shown in FIG. 2 (A), a plurality of laser lights are symmetrically incident on the irradiation surface. for that reason,
The reflected light of the laser light 1 follows the optical path where the laser light 2 reaches the irradiation surface, and the reflected light of the laser light 2 is the laser light 1
Follows the optical path that led to the incident surface. In other words, each reflected light behaves like the returned light,
There is a possibility of adverse effects such as laser output and frequency fluctuations and rod breakage. Therefore, in order to remove the reflected light and stabilize the laser oscillation, it is preferable to install an isolator. For example, the nonlinear optical element 102
If it is installed between the mirror 103 and the mirror 103, the reflected light can be removed.

Next, a method of irradiating the entire surface of the substrate with such a laser beam will be described with reference to FIG.

The substrate 110 (or FIG.
The stage 111) is moved in the direction indicated by 112, and then in the direction indicated by 113. By repeating this operation, the entire surface of the substrate 110 can be irradiated. (FIG. 3A) Further, the substrate 110 (or the stage 111 in FIG. 1) is moved in the direction indicated by 112 with respect to the laser light,
Further, it may be moved in the direction indicated by 114 and then in the direction indicated by 113.
The operation of moving 10 (or the stage 111 of FIG. 1) in the direction indicated by 112 and further moving it in the direction indicated by 114 may be repeated a plurality of times and then moved in the direction indicated by 113. (FIG. 3B) Of course, the entire surface of the substrate may be irradiated by moving the laser light.

Next, the case of crystallizing a semiconductor film using such an irradiation method will be described. When the semiconductor film is irradiated with the laser light, the irradiated region becomes in a molten state and is cooled and solidified as time passes. If the laser light is irradiated while being moved, regions in a molten state are formed one after another, while there are also regions that cool and solidify over time. That is, a temperature gradient is formed in the semiconductor film, crystal grains grow in the moving direction of the laser light, and large grain crystal grains are formed in parallel.

By obtaining a crystalline semiconductor film in which large-sized crystal grains are formed in parallel, the performance of the semiconductor device can be greatly improved. For example, taking a TFT as an example, by forming large-sized crystal grains in parallel, the number of crystal grain boundaries that can be included in the channel formation region can be reduced. In other words, the number of times carriers cross the crystal grain boundary can be extremely reduced, so that high mobility (field effect mobility) equal to or higher than that of a transistor including a single crystal semiconductor can be obtained and the on-state current can be increased. Value (drain current value that flows when the TFT is in the on state), off current value (drain current value that flows when the TFT is in the off state), threshold voltage, S value, and field effect mobility. Will also be possible. In this way, the electrical characteristics of the TFT can be improved, and further the operating characteristics and reliability of the semiconductor device can be improved. Since there are almost no crystal grain boundaries in the moving direction of the laser light, it is preferable to manufacture a TFT having a channel forming region parallel to this direction.

Further, since the entire surface of the semiconductor film is irradiated with laser light to form crystal grains, the width of the crystal grains and the pitch p of interference formed by the laser light divided into a plurality can be matched. desirable. Assuming that the wavelength of the laser light is λ and the incident angle is θ, sin θ = λ / p ∴θ = arcsin (λ / p) holds from FIG. 2A. For example, when the width of the formed crystal grain is 1 to 10 μm using the second harmonic (wavelength 532 nm) of a YAG laser or a YVO ₄ laser, θ = arcsin (532/1000) = 32.14 θ = arcsin From (532/10000) = 3.05, the incident angle θ is 3 to 32 degrees.

If the width of the formed crystal grains is 10 μm or more, there is a high possibility that cracks will occur in the crystal and defects will occur. On the other hand, if it is less than 1 μm, the crystal grain boundaries in the film increase, which causes a leak current. Therefore, the width of the crystal grains is preferably in the range of 1 to 10 μm.
By using such an irradiation method, laser annealing can be performed on the entire surface of a large area substrate. Further, when the semiconductor film is crystallized by such laser annealing, it becomes possible to form a semiconductor film in which large-sized crystal grains exist in parallel. Therefore, the crystal grain boundaries are reduced, the mobility (field effect mobility) is improved, and the on-current value (the drain current value that flows when the TFT is in the on state) and the off current value (the drain current that flows when the TFT is in the off state) flow. It is also possible to reduce variations in drain current value), threshold voltage, S value, and field effect mobility. Therefore, the electrical characteristics of the TFT manufactured using the semiconductor film can be improved, and the operation characteristics and reliability of the semiconductor device can be improved. Further, when the laser light is incident perpendicularly to the substrate surface, the laser light reflected from the back surface of the substrate and the irradiated laser light interfere with each other on the substrate surface, resulting in non-uniform energy density distribution, and There is a problem that a semiconductor film with non-uniformity is formed, but by irradiating the substrate with laser light obliquely, this problem can be solved and a uniform crystalline semiconductor film can be formed. .

The present invention having the above structure will be described in more detail with reference to the following examples.

[0047]

EXAMPLE 1 In this example, a method and apparatus for irradiating the entire surface of a substrate with laser light will be described with reference to FIG.

Laser light emitted from the laser 101 is preferably converted into higher harmonics by the non-linear optical element 102. In this embodiment, a continuous wave YA is used as the laser 101.
The G laser is used and converted into the second harmonic by the non-linear optical element 102.

Then, by irradiating the mirror 103 with the laser light, the optical path of the laser light is divided into two directions, and the respective laser lights are made incident on the mirrors 104a and 104b. And, preferably, the cylindrical lenses 105a, 10
By 5b, the length is reduced in one direction of the laser light. By doing so, the energy density can be increased.

The laser light reflected by the mirrors 104a and 104b reaches the substrate 110 which is the irradiation surface. That is,
The laser light reflected by the mirrors 104a and 104b is superimposed on the substrate 110 which is the irradiation surface. As shown in FIG.
On the substrate 110, the laser beams arriving from two directions interfere with each other to generate a periodic energy distribution. This can be regarded as a large number of dot-shaped laser lights arranged, and the laser light irradiation can be performed more efficiently than in the case where there is one dot-shaped laser light.

Although not shown, it is desirable to install an isolator because the respective reflected lights may follow the optical paths leading to each other and adversely affect the laser.

For such a laser beam, the substrate 100
(Or the stage 111 in FIG. 1) is moved in the direction indicated by 112, and then in the direction indicated by 113. By repeating this operation, the entire surface of the substrate can be irradiated. (FIG. 3A) In addition, the substrate 100 for the laser light is used.
(Or the stage 111 in FIG. 1) is moved in the direction indicated by 112, and further in the direction indicated by 114, and then 1
Alternatively, the substrate 100 (or the stage 111 in FIG. 1) 112 may be moved in the direction indicated by reference numeral 13 to the laser beam.
It is also possible to move in the direction indicated by (1) and further move in the direction indicated by (114) a plurality of times, and then move in the direction indicated by (113). (FIG. 3B) Of course, the entire surface of the substrate may be irradiated by moving the laser light.

In this way, the entire surface of the substrate can be efficiently irradiated with the laser light. Using this irradiation method,
Annealing of the semiconductor film and activation of the impurity element can be performed.

[Embodiment 2] In this embodiment, a method and apparatus for irradiating the entire surface of the substrate with laser light by a laser light dividing method different from that of Embodiment 1 will be described with reference to FIG.

The laser light emitted from the laser 101 is not
It is desired that the linear optical element 102 converts the harmonics.
Yes. In this embodiment, the laser 101 is a continuous wave Y
VO _FourA laser is used, and the third nonlinear optical element 102 is used.
Convert to harmonics.

By irradiating the prism 121 with the laser light, the optical path of the laser light is divided into two directions, and the respective laser lights are incident on the mirrors 122a and 122b. And, preferably the cylindrical lens 105
The length of the laser beam in one direction is reduced by a and 105b. By doing so, the energy density can be increased.

Subsequently, the laser light is applied to the substrate 11 which is the irradiation surface.
Reach 0. That is, the laser light reflected by the mirrors 122a and 122b is superimposed on the substrate 110 which is the irradiation surface. As a result, as shown in FIG.
In the above, the laser beams arriving from two directions interfere with each other, and a periodic energy distribution is generated. This state can be regarded as a large number of dot-shaped laser lights arranged, and the laser light irradiation can be performed more efficiently than in the case where there is one dot-shaped laser light.

The method of moving the substrate is described in the first embodiment.
Is the same as.

In this way, the entire surface of the substrate can be efficiently irradiated with the laser light. Using this irradiation method, the semiconductor film can be annealed and the impurity element can be activated.

[Embodiment 3] In this embodiment, FIG. 5 is used as a method and apparatus for dividing a laser beam by a method different from those of the first and second embodiments and irradiating the whole surface of the substrate with the laser beam. Explain.

Laser light emitted from the laser 101 is preferably converted into higher harmonics by the non-linear optical element 102. In this embodiment, a YLF laser is used as the laser 101, and the nonlinear optical element 102 converts it into the third harmonic.

Then, the laser light is split by being incident on the cylindrical lens array 131. In this embodiment, the number of divisions is 4. Subsequently, the cylindrical lens 132 collects and diverges the laser light. This makes it possible to make the traveling directions (that is, the optical paths of the laser beams) of the respective laser beams divided into four different from each other, so that it becomes easy to make the respective laser beams enter different optical elements. Then, the divided laser light is made incident on the lenses 133a to 133c. The lenses 133a and 133c are installed asymmetrically with respect to the lens 133b (specifically, the distance (X) between the side surface of the lens 133b and the lens 133a and the lens 133b).
Of the lens 133c and the distance (Y) of the lens 133c), and 133a, 133c on the irradiation surface.
It is possible to shift the energy distribution between the interference due to the laser light that has passed through and the interference due to the two laser lights that have passed through 133b. If they are installed symmetrically, it is possible to increase the height difference of the energy distribution of the laser light on the irradiation surface. It is desirable that the lenses 133a and 133c be movable by using a micrometer or the like because fine adjustment is possible.

The two laser beams that have passed through the lenses 133a and 133c are at both ends of the laser beam emitted from the laser 101, and therefore have a lower energy density than the laser beam that has passed through the lens 133b. Therefore, the lens 133
a, 133c and the interference of two laser beams transmitted through the lens 133b and the energy distribution of two laser beams are shifted by, for example, a half cycle, and overlapped, thereby generating a portion with extremely low energy density on the irradiation surface. Can be prevented. (Fig. 6) Of course, the energy density of each laser light is made the same, and the lens 133
a, 133c and the interference due to the laser beam transmitted through
It is also possible to create a laser beam having a uniform energy distribution by shifting the energy distributions of the two laser beams that have passed through b and the interference with each other by shifting them by a half cycle. (Figure 7)

Further, the lenses 133a to 133c and the substrate 1
A cylindrical lens may be installed between 10.

The method of moving the substrate is described in the first embodiment.
Is the same as.

In this way, the entire surface of the substrate can be efficiently irradiated with the laser light. Using this irradiation method,
Annealing of the semiconductor film and activation of the impurity element can be performed.

Further, in the present embodiment, the laser light is condensed and diverged by the cylindrical lens 132 and then condensed by the lens 133, but a plurality of laser lights may be interfered by 132. .

[Embodiment 4] In this embodiment, a method and an apparatus for dividing a laser beam by a method different from those of the first to third embodiments and irradiating the whole surface of the substrate with the laser light will be described with reference to FIG. Explain.

Laser light emitted from the laser 101 is preferably converted into higher harmonics by the non-linear optical element 102. As the laser 101, continuous oscillation or pulse oscillation YAG laser, YVO ₄ laser, YLF laser, YA
A 10 ₃ laser, a glass laser, a ruby laser, an alexandrite laser, a Ti: sapphire laser, or the like can be used. In this embodiment, a YLF laser is used,
Convert to the second harmonic.

Then, the prism 141 is irradiated with laser light to divide the prism 141. In this embodiment, the number of divisions is 4. The prism 141 is the cylindrical lens array 131 and the cylindrical lens 132 shown in the third embodiment.
Have the same role as the combination of. Since the number of optical elements can be reduced from 2 to 1 by using the prism 141, the optical transmittance can be improved. Also,
There is also an effect that the optical path length may be shorter than that of the system shown in the third embodiment. The short optical path is particularly effective when installed in a clean room where the cost per unit area is very high. Then, the divided laser light is passed through the lens 13
3a to 133c. Lenses 133a and 133
c is installed asymmetrically with respect to the lens 133b, that is, by installing each lens at a position where the distance between the lenses 133a and 133b and the distance between the lenses 133c and 133b are different, 1
Interference due to the laser light transmitted through 33a and 133c and 1
It is possible to shift the interference caused by the two laser beams that have passed through 33b. If they are installed symmetrically, it is possible to increase the height difference of the energy distribution of the laser light on the irradiation surface. It is desirable that the lenses 133a and 133c be movable by using a micrometer or the like because fine adjustment is possible.

The two laser beams transmitted through the lenses 133a and 133c are located at both ends of the laser beam emitted from the laser 101, and therefore have a lower energy density than the laser beam transmitted through the lens 133b. Therefore, the lens 133
a, 133c and the interference of the two laser beams transmitted through the lens 133b are overlapped with each other, for example, by shifting by half a period, so that an extremely low energy density portion is generated on the irradiation surface. Can be prevented. (FIG. 6) Of course, if the energy densities of the respective laser lights are made the same and the interference due to the laser light transmitted through the lenses 133a and 133c and the interference due to the two laser lights transmitted through the lens 133b are shifted by a half cycle, they are overlapped. It is also possible to produce laser light with a uniform energy density. (Figure 7)

Further, the lenses 133a to 133c and the substrate 1
A cylindrical lens may be installed between 10.

The method of moving the substrate is described in the first embodiment.
Is the same as.

In this way, the entire surface of the substrate can be efficiently irradiated. Using this irradiation method, the semiconductor film can be annealed and the impurity element can be activated.

[Embodiment 5] In this embodiment, a method for manufacturing an active matrix substrate will be described with reference to FIGS. In this specification, a CMOS circuit and a driving circuit,
A substrate in which a pixel portion including a pixel TFT and a storage capacitor is formed over the same substrate is referred to as an active matrix substrate for convenience.

First, in this embodiment, a substrate 400 made of glass such as barium borosilicate glass or aluminoborosilicate glass is used. Note that as the substrate 400, a quartz substrate, a silicon substrate, a metal substrate, or a stainless substrate on which an insulating film is formed may be used.
Alternatively, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used.

Next, a base film 401 made of an insulating film such as a silicon oxide film, a silicon nitride film or a silicon oxynitride film is formed on the substrate 400 by a known method (a sputtering method, an LPCVD method, a plasma CVD method or the like). Although a two-layer structure is used as the base film 401 in this embodiment, a single layer film of the insulating film or a stacked structure of two or more layers may be used.

Next, a semiconductor layer is formed on the base film.
As the semiconductor layer, a semiconductor film having a thickness of 25 to 80 nm (preferably 30 to 60 nm) is formed by a known means (sputtering method, LPCVD method, plasma CVD method, etc.) and crystallized by a laser crystallization method. In the laser crystallization method, any one of Examples 1 to 4 is applied, laser light emitted from a laser is divided into a plurality of laser lights by an optical system, and then combined into one to form interference, Irradiate the semiconductor film.
Of course, in addition to the laser crystallization method, other known crystallization methods (thermal crystallization method using RTA or furnace annealing, thermal crystallization method using a metal element that promotes crystallization, etc.)
May be combined with. Then, the obtained crystalline semiconductor film is patterned into a desired shape to form the semiconductor layer 40.
2 to 406 are formed. Examples of the semiconductor film include an amorphous semiconductor film, a microcrystalline semiconductor film, and a crystalline semiconductor film, and a compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be applied.

In this embodiment, first, an amorphous silicon film having a thickness of 55 nm is formed by using the plasma CVD method. Then, after converting the laser light emitted from the continuous oscillation YVO ₄ laser with an output of 10 W into the second harmonic by the non-linear optical element, it is converted into a plurality of laser lights by the optical system shown in any one of Examples 1 to 4. Divide and combine on the substrate to form interference. The distribution of energy density at this time is wavy,
The crystallization peak value 150 mJ / cm ² or more (preferably 200 mJ / cm ² or higher) is required laser beam having an energy density of. And 10-200 cm /
The stage is moved at a speed of about s for irradiation to form a crystalline silicon film. Then, the semiconductor layers 402 to 406 are formed by a patterning process using a photolithography method.

After forming the semiconductor layers 402 to 406, a slight amount of impurity element (boron or phosphorus) may be doped in order to control the threshold value of the TFT.

Next, a gate insulating film 407 which covers the semiconductor layers 402 to 406 is formed. The gate insulating film 407 is formed by a plasma CVD method or a sputtering method and has a thickness of 40 to
It is formed of an insulating film containing silicon with a thickness of 150 nm. In this embodiment, a silicon oxynitride film (composition ratio Si = 32%, O = 59%, N =) having a thickness of 110 nm is formed by the plasma CVD method.
7%, H = 2%). Of course, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a laminated structure.

When a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) is formed by the plasma CVD method.
And O ₂ are mixed, reaction pressure 40 Pa, substrate temperature 300-
400 ° C., high frequency (13.56 MHz) power density 0.
It can be formed by discharging at 5 to 0.8 W / cm ² .
The silicon oxide film formed in this manner has a thickness of 400
Good characteristics as a gate insulating film can be obtained by thermal annealing at ˜500 ° C.

Then, a film having a thickness of 20 is formed on the gate insulating film 407.
A first conductive film 408 having a thickness of 100 nm and a thickness of 100 to 4
A second conductive film 409 having a thickness of 00 nm is stacked. In this embodiment, a first conductive film 408 made of a TaN film having a film thickness of 30 nm and a second conductive film 409 made of a W film having a film thickness of 370 nm are laminated. The TaN film is formed by a sputtering method and is sputtered in an atmosphere containing nitrogen using a Ta target. The W film was formed by the sputtering method using a W target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to reduce the resistance in order to use it as a gate electrode, and the resistivity of the W film is 20 μΩc.
It is desirable to be m or less. Although the resistivity of the W film can be lowered by enlarging the crystal grains, when the W film contains many impurity elements such as oxygen, crystallization is hindered and the resistance is increased. Therefore, in the present embodiment, the W film is formed by the sputtering method using a high-purity W (purity 99.9999%) target, and with careful consideration that impurities are not mixed from the gas phase during film formation. By forming, a resistivity of 9
˜20 μΩcm can be realized.

In this embodiment, the first conductive film 408 is used.
Is TaN and the second conductive film 409 is W, but is not particularly limited, and Ta, W, Ti, Mo, Al, Cu,
It may be formed of an element selected from Cr or Nd, or an alloy material or a compound material containing the above element as a main component.
Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. Also, AgP
You may use dCu alloy. In addition, the first conductive film is formed of a tantalum (Ta) film, the second conductive film is formed of a W film, and the first conductive film is formed of a titanium nitride (TiN) film. Is a W film, the first conductive film is a tantalum nitride (TaN) film, the second conductive film is an Al film, and the first conductive film is a tantalum nitride (TaN) film. The second conductive film may be a combination of Cu films.

Next, masks 410 to 415 made of resist are formed by photolithography, and a first etching process for forming electrodes and wirings is performed. The first etching process is performed under the first and second etching conditions. (FIG. 9B) In this example, as the first etching condition, an ICP (Inductively Coupled Plasma) etching method was used, and CF ₄ , Cl _2, and O ₂ were used as etching gases. Each gas flow rate ratio is set to 25:25:10 (sccm) and 500 W of RF (13.56 MHz) power is applied to the coil type electrode at a pressure of 1 Pa to generate plasma and perform etching. RF (13.56 MHz) power of 150 W is also applied to the substrate side (sample stage) to apply a substantially negative self-bias voltage.
The W film is etched under the first etching condition so that the end portion of the first conductive layer is tapered.

After that, the masks 410 to 410 made of resist are formed.
Without removing 415, the second etching condition was changed, CF ₄ and Cl ₂ were used as etching gases, and the respective gas flow rate ratios were set to 30:30 (sccm) to form a coil-type electrode at a pressure of 1 Pa. An RF (13.56 MHz) power of 500 W was applied to generate plasma and etching was performed for about 30 seconds. 20 W RF (13.56) on the substrate side (sample stage)
MHz) power is applied and a substantially negative self-bias voltage is applied. Under the second etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time may be increased at a rate of about 10 to 20%.

In the first etching process, the shape of the mask made of resist is adjusted to
The edges of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. The angle of this tapered portion is 15 to 45 °. Thus, the first shape conductive layers 417 to 422 (first conductive layers 417a to 422a and second conductive layers 417b to 42) including the first conductive layer and the second conductive layer are formed by the first etching treatment.
2b) is formed. 416 is a gate insulating film,
The area not covered with the conductive layers 417 to 422 in the shape of 20 is 20
A thinned region is formed by etching about 50 nm.

Next, a second etching process is performed without removing the resist mask. (FIG. 9 (C)) Here, CF ₄ , Cl _2, and O ₂ are used as etching gas,
The W film is selectively etched. At this time, the second conductive layers 428b to 433b are formed by the second etching treatment. On the other hand, the first conductive layers 417a to 422a are hardly etched, and the second shape conductive layers 428 to 422a are not etched.
33 is formed.

Then, the first doping process is performed without removing the resist mask to add the impurity element imparting n-type to the semiconductor layer at a low concentration. The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose amount is 1 × 10 ^{13 to} 5
The acceleration voltage is set to × 10 ¹⁴ / cm ² and the acceleration voltage is set to 40 to 80 keV. In this embodiment, the dose amount is 1.5 × 10 ¹³ / cm ² and the acceleration voltage is 60 keV. An element belonging to Group 15 is used as the impurity element imparting n-type, typically phosphorus (P) or arsenic (As), but phosphorus (P) is used here. In this case, the conductive layers 428 to 433 are n
This serves as a mask for the impurity element imparting the mold, and the impurity regions 423 to 427 are formed in a self-aligned manner. An impurity element imparting n-type is added to the impurity regions 423 to 427 in a concentration range of 1 × 10 ¹⁸ to 1 × 10 ²⁰ / cm ³ .

After removing the masks made of resist, new masks 434a to 434c made of resist are formed, and the second doping process is performed at an acceleration voltage higher than that of the first doping process. The conditions of the ion doping method are a dose amount of 1 × 10 ¹³ to 1 × 10 ¹⁵ / cm ² and an acceleration voltage of 60.
~ 120 keV. In the doping process, the second conductive layers 428b to 432b are used as a mask for the impurity element, and doping is performed so that the semiconductor layer below the tapered portion of the first conductive layer is added with the impurity element. Subsequently, the acceleration voltage is lowered from the second doping process and the third doping process is performed to obtain the state of FIG. The condition of the ion doping method is that the dose amount is 1 × 10 ¹⁵ to 1 × 10 5.
^The acceleration voltage is set to ¹⁷ / cm ² and the acceleration voltage is set to 50 to 100 keV. By the second doping treatment and the third doping treatment, the low-concentration impurity region 43 overlapping with the first conductive layer 43 is formed.
6, 442 and 448 are added with an impurity element imparting n-type in a concentration range of 1 × 10 ^{18 to} 5 × 10 ¹⁹ / cm ³ , and 1 × is added to the high concentration impurity regions 435, 441, 444 and 447.
An impurity element imparting n-type is added within a concentration range of 10 ^{19 to} 5 × 10 ²¹ / cm ³ .

Of course, by setting an appropriate acceleration voltage,
The second doping process and the third doping process are 1
It is possible to form the low-concentration impurity region and the high-concentration impurity region by performing the doping process once.

Next, after removing the resist masks, new resist masks 450a to 450a are formed.
c is formed and a fourth doping process is performed. By the fourth doping process, impurity regions 453, 454, 4 in which an impurity element imparting a conductivity type opposite to the one conductivity type is added to a semiconductor layer which becomes an active layer of a p-channel TFT.
59 and 460 are formed. Second conductive layers 428a-43
Using 2a as a mask for the impurity element, the impurity element imparting p-type is added to form an impurity region in a self-aligned manner. In this embodiment, the impurity regions 453, 454,
459 and 460 are formed by an ion doping method using diborane (B ₂ H ₆ ). (FIG. 10B) At the time of the fourth doping process, the semiconductor layer forming the n-channel TFT is covered with masks 450a to 450c made of resist. Although phosphorus is added to the impurity regions 453 and 459 at different concentrations by the first to third doping processes, the concentration of the impurity element imparting p-type is 1 × 10 ^{19 to} 5 in each of the regions. × 10 ²¹
Doping so that the concentration of atoms / cm ³ causes no problem because it functions as a source region and a drain region of the p-channel TFT.

Through the above steps, the impurity regions are formed in the respective semiconductor layers.

Next, a mask 450a made of resist
To 450c are removed to form a first interlayer insulating film 461. As the first interlayer insulating film 461, plasma C is used.
The thickness is 100 to 200 using the VD method or the sputtering method.
It is formed of an insulating film containing silicon as nm. In this embodiment, a silicon oxynitride film having a thickness of 150 nm is formed by a plasma CVD method. Of course, the first interlayer insulating film 461 is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a laminated structure.

Next, as shown in FIG. 10C, a laser irradiation method is used as the activation treatment. In the laser irradiation method, any one of Embodiments 1 to 4 is applied, laser light emitted from a laser is divided into a plurality of laser lights by an optical system, and then combined into one to form interference, and a semiconductor film is formed. To irradiate.

In this embodiment, Y of continuous oscillation with an output of 10 W is used.
The laser light emitted from the VO ₄ laser is converted into a third harmonic by a non-linear optical element, and then divided into a plurality of laser lights using the optical system according to any one of Examples 1 to 4, and the laser light is split onto the substrate. And combine to form interference. At this time, the distribution of energy density becomes wavy, but for crystallization, the peak value is 80 mJ / cm ² or more (preferably 100 mJ / c).
Laser light having an energy density of m ² or more) is required. Then, the stage is moved at a speed of about 10 to 200 cm / s for irradiation.

Further, activation treatment may be performed before forming the first interlayer insulating film.

Then, heat treatment (1 at 300 to 550 ° C.)
Hydrogenation can be performed by performing a heat treatment for 12 hours. This step is a step of terminating the dangling bond of the semiconductor layer with hydrogen contained in the first interlayer insulating film 461. The semiconductor layer can be hydrogenated regardless of the presence of the first interlayer insulating film. Plasma hydrogenation (using hydrogen excited by plasma) as another means of hydrogenation
Or 300 to 45 in an atmosphere containing 3 to 100% hydrogen
You may perform heat processing for 1 to 12 hours at 0 degreeC.

Next, a second interlayer insulating film 462 made of an inorganic insulating film material or an organic insulating material is formed on the first interlayer insulating film 461. In this embodiment, the film thickness is 1.6 μm
The acrylic resin film of
cp, preferably 40 to 200 cp, and the one having irregularities on the surface is used.

In this example, in order to prevent specular reflection, the surface of the pixel electrode was made uneven by forming a second interlayer insulating film having an uneven surface. Further, in order to make the surface of the pixel electrode uneven so as to achieve light scattering, a convex portion may be formed in a region below the pixel electrode. In that case, since the projection can be formed using the same photomask as that for forming the TFT, the projection can be formed without increasing the number of steps. Note that this convex portion may be appropriately provided on the substrate in the pixel portion region other than the wiring and the TFT portion. Thus, the unevenness is formed on the surface of the pixel electrode along the unevenness formed on the surface of the insulating film covering the convex portion.

A film having a flat surface may be used as the second interlayer insulating film 462. In that case, after forming the pixel electrode, a step such as a known sandblasting method or etching method is added to make the surface uneven so as to prevent specular reflection and scatter reflected light to increase the whiteness. Is preferred.

Then, in the drive circuit 506, wirings 463 to 467 electrically connected to the respective impurity regions.
To form. Note that these wirings have a thickness of 50 nm.
A laminated film of an i film and an alloy film (alloy film of Al and Ti) having a film thickness of 500 nm is formed by patterning. Of course, the structure is not limited to the two-layer structure, and may be a single-layer structure or a laminated structure of three or more layers. Also, as the wiring material,
It is not limited to Al and Ti. For example, Al or C on the TaN film
Wiring may be formed by forming u and then patterning a laminated film having a Ti film formed thereon. (Figure 11)

Further, in the pixel portion 507, the pixel electrode 470, the gate wiring 469, and the connection electrode 468 are formed. By this connection electrode 468, the source wiring (a stack of 443a and 443b) is electrically connected to the pixel TFT. The gate wiring 469 is electrically connected to the gate electrode of the pixel TFT. Also, the pixel electrode 4
70 is electrically connected to the drain region of the pixel TFT, and further electrically connected to the semiconductor layer 459 which functions as one electrode forming a storage capacitor. Further, as the pixel electrode 470, it is desirable to use a material having excellent reflectivity such as a film containing Al or Ag as a main component, or a laminated film thereof.

As described above, the n-channel TFT 50
1 and a p-channel TFT 502 CMOS circuit,
And driving circuit 506 having n-channel TFT 503
Then, the pixel portion 507 including the pixel TFT 504 and the storage capacitor 505 can be formed over the same substrate. Thus, the active matrix substrate is completed.

N-channel TFT 50 of drive circuit 506
Reference numeral 1 denotes a channel formation region 437, and a low-concentration impurity region 4 overlapping with the first conductive layer 428a forming part of the gate electrode.
36 (GOLD region), a high-concentration impurity region 452 functioning as a source region or a drain region, and an impurity region 451 in which an impurity element imparting n-type and an impurity element imparting p-type are introduced. A channel formation region 440, a high-concentration impurity region 454 functioning as a source region or a drain region, and an impurity element imparting n-type are provided in the p-channel TFT 502 which is connected to the n-channel TFT 501 with an electrode 466 to form a CMOS circuit. And an impurity region 453 in which an impurity element imparting p-type conductivity is introduced. In addition, the n-channel type TFT5
03 includes a channel formation region 443, a low-concentration impurity region 442 (GOLD region) overlapping with the first conductive layer 430a forming part of a gate electrode, a high-concentration impurity region 456 functioning as a source region or a drain region, and n. It has an impurity region 455 into which an impurity element imparting a type and an impurity element imparting a p-type are introduced.

The pixel TFT 504 in the pixel portion has a channel formation region 446, a low concentration impurity region 445 (LDD region) formed outside the gate electrode, and a high concentration impurity region 458 functioning as a source region or a drain region. ing. Further, an impurity element imparting n-type conductivity and an impurity element imparting p-type conductivity are added to the semiconductor layer functioning as one electrode of the storage capacitor 505. The storage capacitor 505 uses the insulating film 416 as a dielectric to form an electrode (432
a and a layer of 432b) and a semiconductor layer.

In the pixel structure of the present embodiment, the end portions of the pixel electrodes are arranged and formed so as to overlap the source wiring so that the gaps between the pixel electrodes are shielded from light without using the black matrix.

A top view of the pixel portion of the active matrix substrate manufactured in this embodiment is shown in FIG. The same reference numerals are used for the portions corresponding to FIGS. 9 to 12.
The chain line AA 'in FIG. 11 corresponds to the cross-sectional view taken along the chain line AA' in FIG. Also, a chain line B in FIG.
-B 'corresponds to the cross-sectional view taken along the chain line BB' in FIG.

[Embodiment 6] In this embodiment, a process of manufacturing a reflective liquid crystal display device from the active matrix substrate manufactured in Embodiment 5 will be described below. 13 for the explanation.
To use.

First, according to the fifth embodiment, after obtaining the active matrix substrate in the state of FIG. 11, the alignment film 567 is formed on at least the pixel electrode 470 on the active matrix substrate of FIG. 11, and rubbing treatment is performed. In this embodiment, before forming the alignment film 567, the organic resin film such as the acrylic resin film is patterned to form the columnar spacers 572 for holding the substrate distance at desired positions. Further, spherical spacers may be dispersed over the entire surface of the substrate instead of the columnar spacers.

Next, the counter substrate 569 is prepared. Next, the coloring layers 570 and 571 and the planarization film 573 are formed over the counter substrate 569. The red colored layer 570 and the blue colored layer 571 are overlapped with each other to form a light shielding portion. In addition, the light-shielding portion may be formed by partially overlapping the red colored layer and the green colored layer.

In this example, the substrate shown in Example 5 is used. Therefore, FIG. 1 showing a top view of the pixel portion of the fifth embodiment.
2 at least the gate wiring 469 and the pixel electrode 470.
It is necessary to shield light from the gap between the gate wiring 469 and the connection electrode 468, and the gap between the connection electrode 468 and the pixel electrode 470. In this example, the colored layers were arranged so that the light-shielding portions formed by stacking the colored layers were overlapped with each other at the positions where they should be shielded, and the counter substrates were bonded together.

As described above, it is possible to reduce the number of steps by shielding the gaps between the pixels with the light-shielding portion formed of the stacked colored layers without forming a light-shielding layer such as a black mask.

Then, a counter electrode 576 made of a transparent conductive film was formed on the flattening film 573 at least in the pixel portion, an alignment film 574 was formed on the entire surface of the counter substrate, and a rubbing treatment was performed.

Then, the active matrix substrate on which the pixel portion and the drive circuit are formed and the counter substrate are sealed with a sealing material 568.
Stick together. A filler is mixed in the sealing material 568, and the two substrates are bonded to each other with a uniform interval by the filler and the columnar spacers. afterwards,
A liquid crystal material 575 is injected between both substrates and completely sealed with a sealant (not shown). A known liquid crystal material may be used as the liquid crystal material 575. In this way, the reflection type liquid crystal display device shown in FIG. 13 is completed. Then, if necessary, the active matrix substrate or the counter substrate is cut into a desired shape. Further, a polarizing plate (not shown) was attached only to the counter substrate. Then, using a known technique, F
I stuck a PC.

The liquid crystal display device manufactured as described above is a TFT manufactured using a semiconductor film in which large-grain crystal grains are formed by irradiation with laser light whose energy distribution is periodic or uniform. Therefore, the liquid crystal display device can have sufficient operating characteristics and reliability. Then, such a liquid crystal display device can be used as a display portion of various electronic devices.

This embodiment can be freely combined with Embodiments 1 to 5.

[Embodiment 7] In this embodiment, a TFT when the active matrix substrate shown in Embodiment 5 is manufactured.
An example of manufacturing a light-emitting device using the manufacturing method of 1 will be described below. In this specification, a light emitting device is a generic term for a display panel in which a light emitting element formed on a substrate is enclosed between the substrate and a cover material, and a display module in which a TFT or the like is mounted on the display panel. Is. Note that the light-emitting element has a luminescence (El
It has a layer (light emitting body) containing a compound capable of obtaining ectro luminescence, an anode layer, and a cathode layer. In addition, luminescence in a compound includes light emission (fluorescence) when returning from a singlet excited state to a ground state and light emission when returning from a triplet excited state to a ground state (phosphorescence). Either of these, or Includes both emissions.

In the present specification, all the layers formed between the anode and the cathode in the light emitting element are defined as the light emitting body. The luminescent material specifically includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, and the like. Basically, a light emitting device has a structure in which an anode layer, a light emitting body, and a cathode layer are sequentially stacked. In addition to this structure, an anode layer, a hole injection layer, a light emitting layer, a cathode layer, and an anode layer It may have a structure in which a hole injecting layer, a light emitting layer, an electron transporting layer, a cathode layer and the like are laminated in this order.

FIG. 14 is a sectional view of the light emitting device of this embodiment. In FIG. 14, the switching TFT 603 provided on the substrate 700 is the n-channel TFT 50 of FIG.
3 is used. Therefore, the description of the structure may be referred to the description of the n-channel TFT 503.

Although the double gate structure in which two channel forming regions are formed is used in this embodiment, a single gate structure in which one channel forming region is formed or a triple gate structure in which three channel forming regions are formed is also possible. good.

The drive circuit provided on the substrate 700 is shown in FIG.
It is formed by using one CMOS circuit. Therefore, the description of the structure is given by the n-channel TFT 501 and the p-channel TFT.
The description of 502 may be referred to. Although a single gate structure is used in this embodiment, a double gate structure or a triple gate structure may be used.

Further, the wirings 701 and 703 function as a source wiring of the CMOS circuit, and 702 functions as a drain wiring.
The wiring 704 functions as a wiring that electrically connects the source wiring and the source region of the switching TFT, and the wiring 705 functions as a wiring that electrically connects the drain wiring and the drain region of the switching TFT.

The current control TFT 604 is p-type in FIG.
It is formed using the channel TFT 502. Therefore,
For the description of the structure, the description of the p-channel TFT 502 may be referred to. Although a single gate structure is used in this embodiment, a double gate structure or a triple gate structure may be used.

The wiring 706 is a source wiring (corresponding to a current supply line) of the current control TFT, and 707 is an electrode electrically connected to the pixel electrode 711 by being overlapped on the pixel electrode 711 of the current control TFT. is there.

711 is a pixel electrode (anode of a light emitting element) made of a transparent conductive film. As the transparent conductive film,
A compound of indium oxide and tin oxide, a compound of indium oxide and zinc oxide, zinc oxide, tin oxide, or indium oxide can be used. Moreover, you may use what added gallium to the said transparent conductive film. The pixel electrode 711 has a flat interlayer insulating film 7 before the wiring is formed.
Form on 10. In this embodiment, it is very important to flatten the step due to the TFT by using the flattening film 710 made of resin. Since the light-emitting body formed later is very thin, the presence of the step may cause the light emission failure. Therefore, it is desirable to flatten the light emitting body before forming the pixel electrode so that the light emitting body can be formed as flat as possible.

After forming the wirings 701 to 707, a bank 712 is formed as shown in FIG. Bank 712 is 10
It may be formed by patterning an insulating film containing 0 to 400 nm of silicon or an organic resin film.

Since the bank 712 is an insulating film,
Attention must be paid to the electrostatic breakdown of the device during film formation.
In this embodiment, carbon particles or metal particles are added to the insulating film that is the material of the bank 712 to lower the resistivity and suppress the generation of static electricity. At this time, the resistivity is 1 × 10 ⁶ to 1 × 1.
The addition amount of carbon particles or metal particles may be adjusted so as to be 0 ¹² Ωm (preferably 1 × 10 ⁸ to 1 × 10 ¹⁰ Ωm).

A light emitting body 713 is formed on the pixel electrode 711. Although only one pixel is shown in FIG. 14, light emitting layers corresponding to each color of R (red), G (green), and B (blue) are separately formed in this embodiment. Further, in this embodiment, the low molecular weight organic light emitting material is formed by the vapor deposition method.
Specifically, a 20-nm-thick copper phthalocyanine (CuPc) film is provided as a hole injecting layer, and a 7-thick film as a light-emitting body is formed thereon.
It has a laminated structure in which a 0 nm thick tris-8-quinolinolato aluminum complex (Alq ₃ ) film is provided. The emission color can be controlled by adding a fluorescent dye such as quinacridone, perylene or DCM1 to Alq ₃ .

However, the above example is an example of an organic light emitting material that can be used as a light emitting body, and it is not necessary to limit to this. A light emitting body (a layer for emitting light and moving carriers therefor) may be formed by freely combining the light emitting layer, the charge transport layer or the charge injection layer. For example, in this embodiment, an example in which a low molecular weight organic light emitting material is used as the light emitting layer is shown, but a medium molecular weight organic light emitting material or a high molecular weight organic light emitting material may be used. In the present specification, an organic light-emitting material having no sublimability and having a number of molecules of 20 or less or a chain of molecules having a length of 10 μm or less is referred to as a medium molecule organic light-emitting material. In addition, as an example of using a polymer organic light emitting material, the hole injection layer has a thickness of 20 nm.
Alternatively, a polythiophene (PEDOT) film may be provided by a spin coating method, and a para-phenylene vinylene (PPV) film having a thickness of about 100 nm may be provided on the polythiophene (PEDOT) film as a laminated structure. By using a PPV π-conjugated polymer, the emission wavelength can be selected from red to blue. Further, it is also possible to use an inorganic material such as silicon carbide for the charge transport layer and the charge injection layer. Known materials can be used as these organic light emitting materials and inorganic materials.

Next, a cathode 714 made of a conductive film is provided on the light emitting layer 713. In this embodiment, an alloy film of aluminum and lithium is used as the conductive film. Of course, a well-known MgAg film (an alloy film of magnesium and silver)
May be used. As the cathode material, a conductive film made of an element belonging to Group 1 or 2 of the periodic table or a conductive film to which those elements are added may be used.

The light emitting element 715 is completed when the cathode 714 is formed. The light emitting element 71 referred to here
Reference numeral 5 denotes a diode formed by the pixel electrode (anode) 711, the light emitting layer 713 and the cathode 714.

It is effective to provide the passivation film 716 so as to completely cover the light emitting element 715. As the passivation film 716, an insulating film including a carbon film, a silicon nitride film, or a silicon nitride oxide film is used, and the insulating films are used as a single layer or a stacked layer in which they are combined.

At this time, it is preferable to use a film having good coverage as the passivation film, and a carbon film, especially D
It is effective to use an LC (diamond-like carbon) film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C. or lower, it can be easily formed over the light-emitting body 713 having low heat resistance. In addition, the DLC film has a high oxygen blocking effect, and thus the light emitting layer 713
It is possible to suppress the oxidation of Therefore, it is possible to prevent the problem that the light emitting body 713 is oxidized during the subsequent sealing step.

Further, a sealing material 717 is provided on the passivation film 716, and a cover material 718 is attached. An ultraviolet curable resin may be used as the sealing material 717, and it is effective to provide a substance having a moisture absorption effect or a substance having an antioxidant effect inside. In addition, in this embodiment, the cover material 718 is a glass substrate, a quartz substrate, or a plastic substrate (including a plastic film) on which carbon films (preferably diamond-like carbon films) are formed.

Thus, the light emitting device having the structure shown in FIG. 14 is completed. Note that it is effective to continuously perform the steps from the formation of the bank 712 to the formation of the passivation film 716 using a multi-chamber system (or in-line system) film formation apparatus without exposing to the atmosphere. . Further, it is also possible to further develop and continuously process up to the step of attaching the cover material 718 without exposing to the atmosphere.

Thus, the n-channel type T is formed on the substrate 700.
FTs 601 and 602, a switching TFT (n-channel type TFT) 603 and a current control TFT (n-channel type TFT) 604 are formed.

Furthermore, as described with reference to FIG.
By providing an impurity region overlapping the gate electrode with an insulating film interposed therebetween, n which is resistant to deterioration due to the hot carrier effect is used.
A channel TFT can be formed. for that reason,
It is possible to realize a highly reliable light emitting device.

Although only the pixel portion and the driving circuit are shown in the present embodiment, the signal dividing circuit, the D / A converter, the operational amplifier, the γ correction circuit, etc. may also be used according to the manufacturing process of the present embodiment. Can be formed on the same insulator, and further, a memory and a microprocessor can be formed.

The light-emitting device manufactured as described above has a TFT manufactured using a semiconductor film in which large-grain crystal grains are formed by irradiation with laser light whose energy distribution is periodic or uniform. Therefore, the operating characteristics and reliability of the light emitting device can be sufficient. Then, such a light emitting device can be used as a display portion of various electronic devices.

Note that this embodiment can be freely combined with any one of Embodiments 1 to 5.

[Embodiment 8] By applying the present invention, various semiconductor devices (active matrix type liquid crystal display device, active matrix type light emitting device, active matrix type EC display device) can be manufactured. That is, the present invention can be applied to various electronic devices in which those electro-optical devices are incorporated in the display unit.

Examples of such electronic devices include video cameras, digital cameras, projectors, head mounted displays (goggles type displays), car navigations, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones, electronic books, etc.). ) And the like. Examples of these are shown in FIGS. 15, 16 and 17.

FIG. 15A shows a personal computer, which has a main body 3001, an image input section 3002, and a display section 30.
03, keyboard 3004 and the like. Display unit 3 of the present invention
003 can be applied.

FIG. 15B shows a video camera, which includes a main body 3101, a display portion 3102, a voice input portion 3103, operation switches 3104, a battery 3105, and an image receiving portion 310.
Including 6 etc. The present invention can be applied to the display portion 3102.

FIG. 15C shows a mobile computer (mobile computer), which includes a main body 3201, a camera portion 3202, an image receiving portion 3203, operation switches 3204, a display portion 3205, and the like. The present invention can be applied to the display portion 3205.

FIG. 15D shows a goggle type display, which includes a main body 3301, a display section 3302 and an arm section 330.
Including 3 etc. The present invention can be applied to the display portion 3302.

FIG. 15E shows a player that uses a recording medium (hereinafter, referred to as a recording medium) in which a program is recorded, and has a main body 3401, a display portion 3402, and a speaker portion 340.
3, a recording medium 3404, operation switches 3405 and the like. This player uses a DVD (D
optical Versatile Disc), CD
It is possible to play music, watch movies, play games, and use the internet. The present invention can be applied to the display portion 3402.

FIG. 15F shows a digital camera, which includes a main body 3501, a display portion 3502, an eyepiece portion 3503, operation switches 3504, an image receiving portion (not shown) and the like. The present invention can be applied to the display portion 3502.

FIG. 16A shows a front type projector including a projection device 3601, a screen 3602 and the like. The present invention can be applied to the liquid crystal display device 3808 which constitutes a part of the projection device 3601 and other drive circuits.

FIG. 16B shows a rear type projector, which includes a main body 3701, a projection device 3702, and a mirror 370.
3, screen 3704 and the like. The present invention is a projection device 3
The invention can be applied to the liquid crystal display device 3808 which forms a part of 702 and other driver circuits.

Note that FIG. 16C is a diagram showing an example of the structure of the projection devices 3601 and 3702 in FIGS. 16A and 16B. Projection devices 3601, 37
02 is a light source optical system 3801, mirrors 3802, 380
4 to 3806, dichroic mirror 3803, prism 3807, liquid crystal display device 3808, retardation plate 380.
9, a projection optical system 3810. Projection optical system 38
Reference numeral 10 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 may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting the phase difference, and an IR film in the optical path indicated by the arrow in FIG. 16C. Good.

FIG. 16D is a diagram showing an example of the structure of the light source optical system 3801 in FIG. 16C. In this embodiment, the light source optical system 3801 includes the reflector 3811, the light source 3812, the lens arrays 3813, and 3.
814, a polarization conversion element 3815, and a condenser lens 3816. Note that the light source optical system shown in FIG. 16D 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.

However, the projector shown in FIG. 16 shows the case where a transmissive electro-optical device is used, and an application example in a reflective electro-optical device and a light emitting device is not shown.

FIG. 17A shows a mobile phone, which is a main body 39.
01, voice output unit 3902, voice input unit 3903, display unit 3904, operation switch 3905, antenna 3906
Including etc. The present invention can be applied to the display portion 3904.

FIG. 17B shows a portable book (electronic book) including a main body 4001, display portions 4002 and 4003, a storage medium 4004, operation switches 4005, an antenna 4006.
Including etc. The present invention can be applied to the display portions 4002 and 4003.

FIG. 17C shows a display, which includes a main body 4101, a support base 4102, a display portion 4103 and the like.
The present invention can be applied to the display portion 4103. The display of the present invention is particularly advantageous when it has a large screen, and is advantageous for a display having a diagonal of 10 inches or more (particularly 30 inches or more).

As described above, the applicable range of the present invention is so wide that it can be applied to electronic devices of various fields. In addition, the electronic device of the present embodiment is one of the first to sixth or seventh embodiments.
It can also be realized by using a configuration composed of a combination of.

[0159]

By adopting the structure of the present invention, the following basic significance can be obtained. (A) A laser beam having high coherence energy can be formed into a laser beam having an energy density suitable for a semiconductor film. (B) It can sufficiently cope with laser light having high coherence. (C) By moving the substrate, it becomes possible to irradiate a large area substrate with laser light. (D) In addition to satisfying the above advantages, laser light irradiation can be efficiently performed in the laser irradiation method and the laser irradiation apparatus that performs the method. Further, in a semiconductor device represented by an active matrix type liquid crystal display device, it is possible to improve the operation characteristics and reliability of the semiconductor device. Further, it is possible to reduce the manufacturing cost of the semiconductor device.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the configuration of a laser irradiation apparatus of the present invention.

FIG. 2 is a diagram showing an example of interference of laser light on an irradiation surface of the present invention.

FIG. 3 is a diagram showing an example of a method of moving a substrate on an irradiation surface of the present invention.

FIG. 4 is a diagram showing an example of a configuration of a laser irradiation apparatus of the present invention.

FIG. 5 is a diagram showing an example of a configuration of a laser irradiation apparatus of the present invention.

FIG. 6 is a diagram showing an example of interference of laser light on an irradiation surface of the present invention.

FIG. 7 is a diagram showing an example of interference of laser light on an irradiation surface of the present invention.

FIG. 8 is a diagram showing an example of interference of laser light on an irradiation surface of the present invention.

9A to 9C are cross-sectional views illustrating a manufacturing process of a pixel TFT and a driver circuit TFT.

FIG. 10 is a cross-sectional view showing a manufacturing process of a pixel TFT and a driver circuit TFT.

11A to 11C are cross-sectional views illustrating a manufacturing process of a pixel TFT and a driver circuit TFT.

FIG. 12 is a top view showing a configuration of a pixel TFT.

FIG. 13 is a cross-sectional view of an active matrix liquid crystal display device.

FIG. 14 is a cross-sectional structural diagram of a driver circuit and a pixel portion of a light emitting device.

FIG. 15 illustrates an example of a semiconductor device.

FIG. 16 illustrates an example of a semiconductor device.

FIG. 17 illustrates an example of a semiconductor device.

Continued front page    F-term (reference) 5F052 AA02 AA17 AA24 BA05 BA11                       BA14 BB02 BB05 BB07 CA10                       DA03 DB02 DB03 DB07 EA12                       FA06 FA19 JA01 JA04                 5F110 AA01 AA16 AA28 BB02 BB04                       CC02 DD01 DD02 DD03 DD05                       DD13 DD14 DD15 DD17 EE01                       EE02 EE03 EE04 EE06 EE09                       EE14 EE23 EE28 EE44 EE45                       FF02 FF04 FF09 FF28 FF30                       GG01 GG02 GG13 GG16 GG25                       GG32 GG43 GG45 GG47 HJ01                       HJ04 HJ12 HJ13 HJ23 HL01                       HL02 HL03 HL04 HL06 HL11                       HL12 HM15 NN03 NN04 NN22                       NN27 NN34 NN35 NN44 NN73                       PP01 PP02 PP03 PP05 PP06                       PP07 PP23 PP29 PP34 QQ01                       QQ04 QQ11 QQ19 QQ23 QQ24                       QQ25

Claims (18)

[Claims] 1. A laser, a first optical system that divides a laser beam emitted from the laser into a plurality of laser beams, and a laser beam that is split by the first optical system are combined, and the laser beam is periodically irradiated on an irradiated surface. A second optical system for forming a laser beam having a wide energy distribution, wherein the first optical system is provided between the laser and the second optical system. Laser irradiation device. 2. A laser irradiation apparatus for irradiating a surface to be irradiated with a laser beam emitted from a laser, comprising a first optical system and a second optical system, wherein the second optical system is the first optical system. Is arranged so that the optical axes of the laser beams divided by the optical system of are overlapped on the irradiated surface, and the laser beam emitted from the laser and passing through the first optical system and the second optical system is A laser irradiation apparatus having a periodic energy distribution on the irradiated surface. 3. The laser irradiation apparatus according to claim 1, wherein the laser beam for irradiating the surface to be irradiated is formed by interfering the laser beams divided into the plurality of laser beams. 4. The first optical system and the second optical system according to claim 1, wherein the first optical system and the second optical system apply a laser beam emitted from the laser to an irradiation surface of a sample. A laser irradiation device, which is installed so as to obliquely irradiate. 5. The first optical system and the second optical system according to claim 1, wherein the first optical system and the second optical system apply a laser beam emitted from the laser to an irradiation surface of a sample. A laser irradiation apparatus, which is installed so as to irradiate at an incident angle of 3 to 32 degrees. 6. The laser irradiation device according to claim 1, wherein the first optical system is a cylindrical lens array, a prism or a mirror. 7. The laser irradiation device according to claim 1, wherein the second optical system is a mirror or a cylindrical lens. 8. The laser irradiation apparatus according to claim 1, wherein the laser is a continuous wave or pulsed solid state laser. 9. The laser according to claim 8, wherein the laser is YAG.
A laser irradiation device characterized by being a laser, a YVO ₄ laser, a YLF laser, a YAlO ₃ laser, a glass laser, a ruby laser, an alexandrite laser, or a Ti: sapphire laser. 10. An optical path of laser beams emitted from the same laser is divided into a plurality of beams by a first optical system, and the laser beams divided into a plurality of beams are obliquely directed to a surface to be irradiated by a second optical system. And a laser beam is synthesized so that the irradiation surface has a periodic energy distribution, and the irradiation surface is irradiated with the laser beam. 11. An optical path of a laser beam emitted from the same laser is divided into a plurality of parts by a first optical system, and the plurality of divided laser beams are obliquely made to a surface to be irradiated by a second optical system. Irradiate the first surface of the irradiated surface.
A laser beam having a periodical energy distribution in the direction, and irradiating the irradiated surface in a first direction of the surface to be irradiated and in a second direction perpendicular to the first direction. Irradiation method. 12. The method according to claim 10 or 11,
The laser irradiation method is characterized in that the laser beam for irradiating the surface to be irradiated is formed by causing a laser beam divided into a plurality of beams by the first optical system to interfere with each other. 13. The laser irradiation method according to claim 10, wherein an angle of the laser beam with which the surface to be irradiated is irradiated is 3 to 32 degrees. 14. The laser irradiation method according to claim 10, wherein the first optical system is a cylindrical lens array, a prism or a mirror. 15. The laser irradiation method according to claim 10, wherein the laser is a continuous wave or pulsed solid-state laser. 16. The laser according to claim 10, wherein the laser is a YAG laser or a YVO ₄ laser.
Laser, YLF laser, YAlO ₃ laser, glass laser, ruby laser, alexandrite laser or T
i: A laser irradiation method, which is a sapphire laser. 17. A method for manufacturing a semiconductor device, which comprises annealing a semiconductor film using the laser irradiation apparatus according to claim 1. Description: 18. A method for manufacturing a semiconductor device, which comprises annealing a semiconductor film using the laser irradiation method according to claim 10. Description: