JP2003203876A - Laser irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that energy density attenuates gradually due to aberration of lens at the end part of a linear, rectangular, or planar laser light formed through an optical system on an irradiation plane or the vicinity thereof, and since energy density is not sufficient but attenuating gradually in such a region (attenuating region) as compared with a region having a high uniformity of energy density, an object being irradiated cannot be annealed uniformly. <P>SOLUTION: Laser light emitted from each of a plurality of lasers is split and laser lights including at least one laser light oscillated from a different laser and having a different energy distribution are multiplexed or laser lights including at least one laser light having a different energy distribution are selected and passed through convex lenses disposed obliquely to the traveling direction of respective laser lights before being multiplexed thus forming a laser light exhibiting excellent uniformity of energy distribution. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam irradiation method and a laser beam irradiation apparatus for carrying out the method (an apparatus including a laser and an optical system for guiding a laser beam output from the laser to an object to be irradiated). . 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 semiconductor film formed on an insulating substrate such as glass is subjected to laser nealing to crystallize it, or to obtain a crystalline semiconductor film with improved crystallinity, and to activate an impurity element. The technology to realize this has been widely studied. 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.

A pulsed laser beam such as an excimer laser is shaped by an optical system so that the shape (the spot of the laser beam) on the irradiation surface becomes rectangular or linear, and the laser beam is moved (or the laser beam The method of performing annealing by moving the irradiation position relative to the surface to be irradiated has high productivity and is industrially excellent (for example, refer to Patent Document 1). In addition, the term "linear" does not mean "line" in a strict sense, but means a rectangle (or an ellipse) having a large aspect ratio. For example, the aspect ratio is 1
Although it indicates 0 or more (preferably 100 to 10000), it is still included in a rectangular laser beam (rectangular beam). Note that the linear shape is for ensuring energy density for performing sufficient annealing on the irradiation target, and sufficient annealing can be performed on the irradiation target even if it is rectangular or planar. It doesn't matter. At present, 15 J / pulse excimer laser is commercially available, and there is a possibility that a laser beam will be used in the future to perform a laser anneal using a planar beam. Unless otherwise defined, the spot of laser light is the energy distribution on the irradiation surface of laser light.

FIG. 10 shows an example of the configuration of an optical system for linearizing the shape of laser light on the irradiation surface. This structure is extremely general, and all the optical systems conform to the structure shown in FIG. This configuration not only converts the cross-sectional shape of the laser light into a linear shape, but also achieves uniform energy of the laser light on the irradiation surface at the same time.
Generally, an optical system that homogenizes beam energy is called a beam homogenizer.

The laser light emitted from the laser 71 is split into spots by the cylindrical array lens 73. This direction will be referred to as the first direction in this specification. It is assumed that the first direction bends in the direction of the light bent by the mirror when the mirror enters in the middle of the optical system. In this configuration, there are seven divisions. After that, the laser beams are combined into one by the irradiation surface 79 by the cylindrical lens 74. As a result, the homogenization and the length of the energy of the linear beam in the longitudinal direction are determined.

Next, the side view of FIG. 10 will be described.
The spot of the laser light emitted from the laser 71 is divided by the cylindrical array lenses 72a and 72b. The direction is referred to as the second direction in this specification. It is assumed that the second direction bends in the direction of the light bent by the mirror when the mirror enters in the middle of the optical system. In this configuration, there are four divisions. These divided laser beams are transmitted by the cylindrical lens 74.
Once combined into one laser beam. It is reflected by the mirror 77, and then doublet cylindrical lens 7
8, the laser light is focused again on the irradiation surface 79 into one laser beam. The doublet cylindrical lens is a lens composed of two cylindrical lenses. As a result, the uniform energy of the linear beam in the short direction and the length in the short direction are determined.

For example, as the laser 71, an excimer laser having a size of 10 mm × 30 mm (both half widths in the beam profile) at the exit of the laser is used, and when the optical system having the configuration shown in FIG. It can be a 125 mm × 0.4 mm linear beam with a uniform distribution.

At this time, if the base material of the optical system is, for example, all quartz, a high transmittance can be obtained. Further, as the coating, it is preferable to use one having a transmittance of 99% or more with respect to the wavelength of the excimer laser used.

Then, the linear beam formed by the above-mentioned structure is gradually shifted in the short direction of the laser beam and is overlapped and irradiated, so that the entire surface of the amorphous semiconductor is subjected to laser anneal and crystallized. Can be activated, the crystallinity can be improved to obtain a crystalline semiconductor film, and the impurity element can be activated.

[0010]

[Patent Document 1] JP-A-8-195357

[0011]

The end of the linear, rectangular, or planar laser beam formed on or near the irradiation surface by the optical system is gradually attenuated in energy density due to lens aberration or the like. (FIG. 11 (A)). In this specification, a region where the energy density is gradually attenuated at the end of the laser beam is called an attenuation region.

Further, with the increase in the area of the substrate and the increase in the output power of the laser, longer linear beams, rectangular beams, and larger planar beams are being formed. This is because it is more efficient to anneal with such a laser beam. However, since the energy density of the end portion of the laser light emitted from the laser is smaller than that in the vicinity of the center, when the optical system further expands, the attenuation region tends to become more prominent.

The attenuation region has a lower energy density than the region having a high uniformity of energy density and is gradually attenuated. Therefore, even if annealing is performed using a laser beam having the above attenuation region, Uniform irradiation cannot be performed on the irradiated body (FIG. 11B). Also,
Even if the annealing is performed by the method of scanning the attenuation regions in an overlapping manner, the annealing conditions are clearly different from those of the region having high uniformity, and thus the irradiation target cannot be uniformly annealed. As described above, it is impossible to treat the region annealed by the attenuation region and the region annealed by the region having high uniformity equally.

For example, when the object to be irradiated is a semiconductor film, the crystallinity differs between the region annealed by the attenuation region and the region annealed by the region of high uniformity. Therefore, even if a TFT is manufactured using a semiconductor film having such regions having different crystallinity, the electrical characteristics of the TFT manufactured in the region annealed by the attenuation region are deteriorated, and variations in the same substrate may occur. It becomes a factor.

Further, as shown in FIG. 10, the optical system for forming the linear beam is complicated. It is very difficult to make optical adjustments to such an optical system, and a large footprint causes a problem that the device becomes large.

Further, when laser light having a high reflectance with respect to the object to be irradiated is used, when the laser light is vertically incident on the object to be irradiated, it returns along the same optical path as when it is incident on the object to be irradiated, so-called return. Light is generated. The return light is a factor that adversely affects the output and frequency of the laser, destroys the rod, and so on.

In view of this, the present invention uses a simpler optical system than the conventional one, and forms a rectangular beam with a reduced attenuation region at the end of the laser beam so that annealing can be performed efficiently. The challenge is to provide. Another object is to provide a laser irradiation method using such a laser irradiation apparatus and a method for manufacturing a semiconductor device including the laser irradiation method in its steps.

[0018]

SUMMARY OF THE INVENTION According to the present invention, laser beams emitted from a plurality of lasers are split, laser beams oscillated from different lasers and having different energy distributions are combined with each other to obtain energy. It is characterized by forming a laser beam having excellent distribution uniformity. here,
Different energy distributions are different distributions that rotate to the same distribution. Further, according to the present invention, laser light emitted from a plurality of lasers is divided, laser lights oscillated from different lasers and including at least one laser light having a different positional relationship are combined with each other, and energy is It is characterized by forming a laser beam having excellent distribution uniformity. In addition, the present invention divides each laser beam emitted from a plurality of lasers, and oscillates from different lasers and has laser beams having different energy distributions are obliquely incident on a convex lens and then emitted. It is characterized in that the laser light having a rectangular shape with excellent uniformity of energy distribution is formed by synthesizing on the irradiation surface or in the vicinity thereof.

There is no interference even if laser beams emitted from different lasers are superposed. Therefore, it is particularly effective when laser light irradiation is performed using a highly coherent laser such as a YVO ₄ laser having a coherent length of tens to hundreds of meters or a YAG laser having a coherence length of 1 cm or more.

Further, by injecting the laser light obliquely with respect to the convex lens, aberrations such as astigmatism are generated, and the shape of the laser light on the irradiation surface or in the vicinity thereof can be made linear.

When superposing the divided laser beams, it is preferable to superpose laser beams having different energy distributions. This is because a uniform laser beam can be obtained by superimposing a large number of laser beams having different energy distributions.

The configuration of the invention relating to the laser irradiation apparatus disclosed in the present specification divides a plurality of lasers and a plurality of first laser beams oscillated from the plurality of lasers into a plurality of second laser beams, respectively. And a means for selecting one of the plurality of first laser beams from the second laser beam and combining them in the same region on or near the irradiation surface.

In the above structure, the laser is a continuous wave or pulsed solid-state laser, a gas laser or a metal laser. As the solid-state laser, continuous oscillation or pulse oscillation YAG is used.
(Nd ³⁺ : YAG, Yb ³⁺ : YAG, Cr ⁴⁺ : YAG)
Laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ (Nd ³⁺ : YAG, Yb ³⁺ : YAG) laser, glass laser, ruby laser, Alexandride laser, Ti: sapphire laser, etc., Examples of the gas laser include a continuous oscillation or pulse oscillation excimer laser, an Ar laser, a Kr laser, and a CO ₂ laser, and examples of the metal laser include a helium cadmium laser, a copper vapor laser, and a gold vapor laser. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention.

Further, in the above structure, it is preferable that the laser light is converted into a harmonic by a non-linear optical element. For example, the YAG laser has
It is known to emit laser light having a wavelength of 1065 nm. The absorption coefficient of the laser beam for the silicon film is very low, and it is technically difficult to crystallize the amorphous silicon film which is one of the semiconductor films as it is. However, this laser light can be converted into a shorter wavelength by using a non-linear optical element, and the second harmonic (532 nm), the third harmonic (355 nm), and the fourth harmonic (266 nm) can be used as harmonics. ) And the fifth harmonic (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.

Further, in the above structure, the dividing means is one or a plurality of kinds selected from a slit, a mirror, a prism, a cylindrical lens and a cylindrical lens array.

Further, in the above-mentioned structure, the synthesizing means is one or more kinds selected from a mirror and a cylindrical lens.

Further, in the configuration of the invention relating to the laser irradiation method disclosed in the present specification, a plurality of first laser beams oscillated from a plurality of lasers are divided into a plurality of second laser beams, respectively, and a plurality of the above-mentioned plurality of laser beams are generated. Each of the first laser lights is selected one by one from the second laser lights and is combined in the same region on or near the irradiation surface.

In the above structure, the laser is a continuous wave or pulsed solid-state laser, a gas laser or a metal laser. As the solid-state laser, continuous oscillation or pulse oscillation YAG is used.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include helium cadmium laser, copper vapor laser and gold vapor laser. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention.

Further, in the above structure, it is desirable that the laser light is converted into a harmonic by a non-linear optical element.

Further, in the structure of the invention relating to the method for manufacturing a semiconductor device disclosed in this specification, a plurality of first laser lights emitted from a plurality of lasers are divided into a plurality of second laser lights, and In each of the first laser light of
One by one is selected from the second laser light as the third laser light, and the third laser light is combined in the same region on or near the irradiation surface to form a fourth laser light, It is characterized in that the fourth laser light is irradiated while moving relative to the semiconductor film.

In the above structure, the laser is a continuous wave or pulsed solid state laser, a gas laser or a metal laser. As the solid-state laser, continuous oscillation or pulse oscillation YAG is used.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include helium cadmium laser, copper vapor laser and gold vapor laser. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention.

Further, in the above structure, it is desirable that the laser light is converted into a harmonic by a non-linear optical element.

Further, in the above structure, the semiconductor film is preferably a film containing silicon. Then, as a substrate for forming the semiconductor film, a glass substrate, a quartz substrate, a silicon substrate, a plastic substrate, a metal substrate, a stainless substrate, a flexible substrate, or the like can be used. Examples of the glass substrate include a substrate made of glass such as barium borosilicate glass or aluminoborosilicate glass. Further, the flexible substrate means PET, PES,
A film-like substrate made of PEN, acrylic, or the like. If a semiconductor device is manufactured using a flexible substrate,
Weight reduction is expected. Aluminum film (AlON, AlN, AlO, etc.), carbon film (DLC (diamond-like carbon)) on the front surface or the front and back surfaces of the flexible substrate.
Etc.) and a barrier layer of SiN or the like are formed in a single layer or a multi-layer, which is desirable because the durability is improved.

According to the present invention, the laser beams oscillated from different lasers are combined on or near the irradiation surface, so that no interference occurs. Further, it is most desirable to combine the laser beams having different energy distributions on or near the irradiation surface, but the optimum combining method differs depending on the mode of the laser light, and therefore the practitioner may determine the combining method appropriately. For example, since the TEM ₀₀ mode laser light has high symmetry, it is possible to obtain a relatively uniform laser light by combining the left half and the right half of the two divided laser lights. Of course, increasing the number of divisions makes it possible to obtain more uniform laser light. Even in other modes, a highly uniform laser beam can be obtained by the same method.

Further, since the semiconductor film formed on the substrate can be irradiated with a rectangular beam having a highly uniform energy distribution, a semiconductor film having uniform physical properties can be obtained. Then, it is possible to reduce variations in electrical characteristics of a TFT manufactured using such a semiconductor film. Then, the operating characteristics and reliability of the semiconductor device manufactured from such a TFT can also be improved.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] In the present embodiment, laser light emitted from a plurality of lasers is split,
An example of an optical system for superposing laser beams having different energy distributions will be described with reference to FIGS. 1 and 2.

Laser light is emitted from each of the lasers 101a and 101b. Here, the lasers 101a, 101
As b, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 101a and 101b may be converted into harmonics by a non-linear optical element.

Further, 102a and 102b are isolators. When laser light having a high reflectance with respect to the irradiation target is used and the laser light is vertically incident on the irradiation target, so-called return light is generated, which returns through the same optical path as when the laser light is incident on the irradiation target. The return light is due to fluctuations in laser output and frequency,
It will be a factor that adversely affects the destruction of the rod. Since the optical system in this embodiment has a symmetrical arrangement,
Each reflected light on the irradiation surface is against each other's laser,
It can have the same adverse effects as return light. Therefore, it is desirable to install the isolators 102a and 102b.

Then, each of the emitted laser beams is emitted from the beam expanders 103a, 104a or 1
03b and 104b. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small, and may not be used depending on the size of the laser light and the like. Of course, the laser light may be expanded not only in one direction but also in two directions. Also,
Cylindrical lenses 103a, 104a, 103b,
It is desirable that 104b is made of synthetic quartz glass because a high transmittance can be obtained. In addition, the cylindrical lens 10
The coating applied to the surface of 3a, 104a or 103b, 104b is preferably one that can obtain a transmittance of 99% or more for the wavelength of the laser light used.

Beam expanders 103a and 104a
Alternatively, the laser beams emitted from 103b and 104b are
It is divided into two directions by the mirrors 105a and 105b.
The situation will be described with reference to FIG. 2A and 2B show the shape of laser light in a cross section perpendicular to the direction of travel of the laser light. The laser light emitted from the laser 101a is reflected by the mirror 105 as shown in FIG.
a is split into a first laser beam and a second laser beam,
The second laser light is incident on the irradiation target 108, and the first laser light is absorbed by the damper 107a. On the other hand, laser 1
As shown in FIG. 2B, the laser light oscillated from 01b is split into the third laser light and the fourth laser light by the mirror 105b, and the third laser light is incident on the irradiation target 108 and The laser light of No. 4 is absorbed by the damper 107b.

Since the two laser beams incident on the irradiation object 108 are emitted from different lasers, interference does not occur even if they are combined. Further, the laser light emitted from the laser 101a is the second laser light which is incident on the irradiation target, and the laser light which is emitted from the laser 101b is the third laser light is incident on the irradiation target. Since laser beams having different energy distributions are combined on the surface or in the vicinity thereof, a rectangular laser beam having excellent uniformity of energy distribution is formed. (Fig. 2 (C))

While irradiating the laser beam formed in this manner, the laser beam is moved relative to the object 108 to be irradiated in a direction indicated by 110 or a direction 111, for example, so that the desired object 108 to be irradiated is irradiated. The area or the entire surface can be illuminated.

When the semiconductor film is annealed by using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

Further, in the present embodiment, the laser light is split by using the mirror, but the present invention is not limited to this, and slits, prisms, cylindrical lenses, cylindrical lens arrays, etc. may be used.

Further, in this embodiment, two lasers are used and the number of divisions of the laser light is two, but the number is not limited to this. It is preferable to use about 10 lasers,
When the number of lasers used is small, it is desirable to use an even number of lasers and divide the laser light into even numbers. Also, the lasers used need not be the same.

Further, in the present embodiment, as shown in FIG. 2, the laser light is divided into equal widths on a plane perpendicular to the traveling direction of the laser light, but the present invention is not limited to this.

Further, in the present embodiment, laser lights having different energy distributions are combined on the irradiation surface or in the vicinity thereof, but the optimum combining method differs depending on the mode of the laser light. Just decide. For example, since the TEM ₀₀ mode laser light has high symmetry, it is possible to obtain a relatively uniform laser light by combining the left half and the right half of the two divided laser lights. Of course, increasing the number of divisions makes it possible to obtain more uniform laser light. Even in other modes, a highly uniform laser beam can be obtained by the same method.

Further, if the coating on the surface of the synthetic quartz glass is changed to an appropriate one according to the wavelength of the laser used, it can be applied to various lasers.

Further, in the present embodiment, a rectangular beam whose irradiation surface has a rectangular shape is formed, but the formed shape is not limited to this. The shape of the laser beam emitted from the laser differs depending on the type of laser, and even if it is shaped by an optical system, it is easily affected by the original shape. For example, the shape of the laser light emitted from the XeCl excimer laser may be a rectangular shape of 10 mm × 30 mm (both are half-value widths in the beam profile), and the laser light emitted from the solid-state laser has a rod shape. If it is cylindrical, it will be circular, and if it is slab, it will be rectangular.
In any of the shapes, there is no problem if the energy density is sufficient for annealing the irradiated body, and the present invention can be applied.

Second Embodiment of the Invention In the present embodiment,
An example of an optical system for splitting laser light emitted from three lasers and superimposing laser light having different energy distributions will be described with reference to FIGS.

Laser light is emitted from each of the lasers 101a to 101c. Here, the lasers 101a to 101
As c, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 101a to 101c may be converted into higher harmonics by a non-linear optical element.

Although not shown, lasers 101a to 101c
Each of the laser beams emitted from each may be expanded by a beam expander. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small.

Laser light emitted from the lasers 101a to 101c is divided into two directions by optical systems 102a to 102c which are a combination of mirrors and cylindrical lenses. This is shown in FIG. With the optical system 102a,
Of the laser light emitted from the laser 101a, only the laser light at the left end (first laser light in FIG. 22A) of the three divisions goes straight, and the other laser light is reflected by the mirror to the damper 110a. To reach. Optical system 102b
The laser light oscillated from the laser 101b is generated by the laser light at the center of the three divisions (second laser light in FIG. 22B).
Laser light of (1) goes straight, and the other laser light is reflected by the mirror and reaches the damper 110b. Of the laser light emitted from the laser 101c by the optical system 102c, only the rightmost laser light (third laser light in FIG. 22C) of the three divisions goes straight, and the other laser light is reflected by the mirror. And reaches the damper 110c. In this way, the laser light that travels straight and the laser light that is reflected are determined by the optical systems 102a to 102c.

Of course, after the respective laser beams are incident on the cylindrical lens array to be split, only the split desired laser beams can be extracted by the slit having the reflecting surface.

The laser light traveling straight by the optical systems 102a to 102c is obliquely incident on the convex lenses 104a to 104c via the mirrors 103a to 103c. By doing so, the focal position shifts due to aberrations such as astigmatism, and the rectangular beam 106 can be formed on the irradiation surface or in the vicinity thereof. In addition, FIG.
As described above, the laser light that has passed through the optical systems 102a and 102c has a shorter length in the major axis direction than the laser light that has passed through the optical system 102b. Therefore, by making the laser light incident from the optical system 102b obliquely, the length in the major axis direction becomes longer, and the lengths of the respective laser lights in the longitudinal direction can be made uniform. Alternatively, there is a method of enlarging with a cylindrical lens or the like.

Further, it is desirable to use, as the coating applied to the surfaces of the convex lenses 104a to 104c, a coating having a transmittance of 99% or more for the wavelength of the laser light used. Further, it is desirable that the convex lens is an aspherical lens whose spherical aberration is corrected. If an aspherical lens is used, the light-collecting property is improved, the aspect ratio is improved, and the energy density distribution is improved.

The laser beams having passed through the convex lenses 104a to 104c are combined on the irradiation surface or in the vicinity thereof to form a rectangular beam 1.
06 is formed (FIG. 22D). The rectangular beams thus formed do not interfere with each other because they are emitted from different lasers. Further, since a plurality of laser beams having different energy distributions are combined on or near the irradiation surface, a rectangular beam having excellent energy distribution uniformity is formed.

Then, while irradiating the rectangular beam thus formed, the object 105 to be irradiated is moved relative to the object 105 in a direction indicated by 108 or a direction indicated by 109, for example. In, the desired area or the entire surface can be irradiated.

However, depending on the wavelength of the laser light, the reflected light on the surface of the object to be irradiated 105 and the object to be irradiated 10
In some cases, the reflected light on the back surface of the substrate on which the 5 is formed interferes. FIG. 23 shows an example of forming the semiconductor film 11 on the substrate 10 as the irradiation target 105. If the reflected light from the semiconductor film 11 and the reflected light from the back surface of the substrate 10 do not overlap, interference by these lights does not occur.

In this case, a plane perpendicular to the irradiation surface,
And, when one of the surface including the short side or the surface including the long side when the shape of the long beam is regarded as a rectangle is defined as the incident surface, the incident angle θ of the laser light is included in the incident surface. When the length of the short side or the long side is W, and the thickness of the substrate which is installed on the irradiation surface and is transparent to the laser light is d, θ ≧ arctan (W / 2
It is desirable to satisfy d). Here, W is a beam length of 15 when it is incident on the irradiation target. When the locus of the laser light is not on the incident surface, the incident angle of the locus projected on the incident surface is θ. When the laser light is incident at this incident angle θ, the reflected light from the front surface of the substrate and the reflected light from the back surface of the substrate do not interfere with each other, and uniform laser light irradiation can be performed. Further, if the Brewster angle is set as the incident angle θ with respect to the object to be irradiated, the reflectance becomes the lowest, so that the laser light can be efficiently used. In the above discussion, the refractive index of the substrate is set to 1. In practice, the refractive index of the substrate is often around 1.5, and if this value is taken into consideration, a calculated value larger than the angle calculated in the above discussion can be obtained. However, since the energy at both ends in the longitudinal direction of the linear beam is attenuated, the influence of interference in this portion is small, and the effect of interference attenuation is sufficiently obtained by the above calculated value. It is desirable that the incident angles of the laser light incident on the irradiation surface all satisfy the above expression θ ≧ arctan (W / 2d).

An antireflection film may be formed on the surface of the object to be irradiated.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

In this embodiment, three lasers are used and the number of laser light divisions is three, but the number is not limited to this.

Further, in the present embodiment, as shown in FIG. 22, the plane is divided into equal widths in the plane perpendicular to the traveling direction of the laser light, but the present invention is not limited to this.

The shape of the laser light differs depending on the type of the laser light emitted from the laser, and the shape of the laser light is likely to be affected by the original shape even if it is shaped by an optical system. For example, XeC
The shape of the laser light emitted from the excimer laser is rectangular, and the shape of the laser light emitted from the solid-state laser is circular if the rod shape is cylindrical, and rectangular if the slab type. is there. The present invention can be applied to any shape.

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

[0067]

[Embodiment 1] In this embodiment, an example of an optical system for splitting laser light oscillated from four lasers and superimposing laser light having different energy distributions will be described with reference to FIGS. Will be explained.

Laser light is emitted from each of the lasers 131a to 131d. Here, the lasers 131a to 131
As d, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 131a to 131d may be converted into higher harmonics by a non-linear optical element.

In this embodiment, a continuous wave YVO ₄ laser is used, and the second harmonic is converted by a non-linear optical element.
The beam diameter of the laser light is 2.25 mm, and the divergence angle is 0.35 mrad.

Although not shown, it is desirable to install an isolator. This is because the optical system in the present embodiment has a symmetrical arrangement, and thus each reflected light on the irradiation surface may adversely affect each other's lasers in the same manner as the return light.

Although not shown, a beam expander may be installed to expand the laser beam in the long and short directions. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small.

The laser beams emitted from the lasers 131a to 131d are slits 132a to 132 having reflecting surfaces.
It is divided into two directions by d. However, the slit 132
Since a to 132d are installed at different positions with respect to the respective laser lights, only the laser lights at the different positions go straight. The situation will be described with reference to FIG. FIG. 4 shows the shape of laser light in a cross section perpendicular to the laser traveling direction. FIG. 4A shows laser light oscillated from the laser 131a, and the slit 132a allows the first light to be emitted.
Laser light of (1) goes straight, and the second to fourth laser lights are reflected and absorbed by the damper 137. FIG. 4B shows a laser 1.
31b shows laser light oscillated from 31b, the second laser light goes straight through the slit 132b, and the first, third,
The fourth laser light is reflected and absorbed by the damper 137. FIG. 4C shows the laser light emitted from the laser 131c. The slit 132c causes the third laser light to travel straight, and the first, second, and fourth laser lights are reflected and absorbed by the damper 137. To be done. FIG. 4D shows the laser 13.
The laser light emitted from 1d is shown, and the slit 1
The fourth laser beam advances straight by 32d, and the first to third laser beams are reflected and absorbed by the damper 137. As described above, the slits 132a to 132d have a role of causing the laser beams having different energy distributions of the respective laser beams to go straight and reflecting the other laser beams.

Next, the traveling direction of the laser light having passed through the slits 132a to 132d is bent by the prisms 133a to 133d. Prisms 133a to 133d
Is installed to combine the laser beams at the same irradiation position.

When the laser light reaching the irradiation surface is the laser light at the end of the original laser light, it is desirable to increase the length of the laser light in the longitudinal direction by the cylindrical lenses 134a and 134d. As shown in Figure 4,
This is because both ends of the laser beam are shorter than those near the center, and therefore, if the length is set to be similar to that near the center, a highly uniform rectangular beam can be obtained when combined on or near the irradiation surface. . In this embodiment, a cylindrical lens having a focal length of 50 mm is installed so that its curvature is parallel to the longitudinal direction.

By the optical system having the above-mentioned structure, the irradiation surface is combined as shown in FIG. Moreover, the result of simulating the shape of the laser beam formed on the irradiation surface is shown in FIG. From Figure 5, 7.1 mm x 2
It can be seen that a 2.2 mm rectangular beam is obtained. Since this rectangular beam is emitted from different lasers, no interference occurs. In addition, since a plurality of laser beams having different energy distributions are combined on the irradiation surface, a rectangular beam with excellent energy distribution uniformity is obtained.

Then, while irradiating the rectangular beam thus formed, the irradiation target 108 is moved by moving relative to the irradiation target 108 in a direction indicated by 110 or a direction indicated by 111, for example. In, the desired area or the entire surface can be irradiated.

Although the number of lasers is 4 and the number of divisions is 4 in this embodiment, the number is not limited to these.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

[Embodiment 2] In this embodiment, an example of an optical system for splitting laser light oscillated from three lasers and superposing laser light having different energy distributions will be described with reference to FIG. To do.

Laser light is emitted from each of the lasers 121a to 121c. Here, the lasers 121a to 121
As c, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 121a to 121c may be converted into higher harmonics by a non-linear optical element.

In this embodiment, a pulse oscillation YAG laser is used, and is converted into a second harmonic by a non-linear optical element.

Each of the emitted laser beams is expanded by the beam expanders 122a to 122c, 123.
a to 123c are enlarged. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small, and may not be used depending on the size of the laser light and the like. Further, it is desirable that the cylindrical lenses 122a to 122c and 123a to 123c are made of synthetic quartz glass because a high transmittance can be obtained.
In addition, the cylindrical lenses 122a to 122c, 12
The coating applied to the surfaces of 3a to 123c is
It is desirable to use a material that can obtain a transmittance of 99% or more for the wavelength of the laser light used.

Beam expanders 122a to 122
The laser light emitted from each of c, 123a to 123c is an optical system 12 in which a mirror and a cylindrical lens are combined.
It is divided into two directions by 4a to 124c. Optical system 12
As for the laser light oscillated from the laser 121a by 4a, only the left laser light of the three divisions goes straight, and the other laser light is reflected by the mirror and reaches the damper 126. Of the laser light emitted from the laser 121b by the optical system 124b, only the central laser light of the three divisions goes straight, and the other laser light is reflected by the mirror and reaches the damper 126. Of the laser light oscillated from the laser 121c by the optical system 124c, only the right laser light of the three divisions goes straight, and the other laser light is reflected by the mirror and reaches the damper 126. In this way, the laser light that travels straight and the laser light that is reflected are determined by the optical systems 124a to 124c.

Of course, after each laser beam is incident on the cylindrical lens array to be divided, only the laser beam in a desired region can be extracted by the slit having the reflecting surface.

Although not shown, when the laser light reaching the irradiation surface is the laser light at the end of the original laser light, the length of the laser light is shorter than the laser light near the center. It is desirable to expand.

The laser beams passed through the optical systems 124a to 124c are combined by the cylindrical lens 125 on or near the irradiation surface to form a rectangular beam. The rectangular beams thus formed do not interfere with each other because they are emitted from different lasers. Further, since a plurality of laser beams having different energy distributions are combined on or near the irradiation surface, a rectangular beam having excellent energy distribution uniformity is formed.

Then, while irradiating the rectangular beam thus formed, the irradiation target 108 is moved by moving relative to the irradiation target 108 in a direction indicated by 110 or a direction indicated by 111, for example. In, the desired area or the entire surface can be irradiated.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

Further, in this embodiment, three lasers are used and the number of divisions of the laser light is three, but the number is not limited to this.

The present embodiment can be freely combined with the first embodiment.

[Embodiment 3] In this embodiment, an optical system for splitting laser light oscillated from two lasers and superimposing laser light having different energy distributions to form a plurality of laser light simultaneously. An example will be described with reference to FIG.

Laser light is emitted from each of the lasers 141a and 141b. Here, the lasers 141a and 141
As b, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 141a and 141b may be converted into higher harmonics by a non-linear optical element.

In this embodiment, a continuous wave YAG laser is used, which is used after being converted into the third harmonic by a non-linear optical element.

Then, the respective emitted laser beams are emitted from the beam expanders 142a, 143a or 1a.
It is enlarged by 42b and 143b. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small, and may not be used depending on the size of the laser light and the like. Further, it is desirable that the cylindrical lenses 142a, 143a, 142b, 143b are made of synthetic quartz glass because a high transmittance can be obtained. Also, the cylindrical lenses 142a, 143a,
The coating applied to the surfaces of 142b and 143b is preferably one that can obtain a transmittance of 99% or more for the wavelength of the laser light used.

The laser beams emitted from the beam expanders 142 and 143 are split into two directions by the optical systems 144a and 144b which are a combination of mirrors and cylindrical lenses. The optical system 144a allows the laser 141a
The laser light oscillated from the laser light on the left of the two splits goes straight, and the laser light on the right is reflected by the mirror. The laser light oscillated from the laser 141b by the optical system 144b is the laser light on the left of the two splits that goes straight, and the laser light on the right is reflected by the mirror. In this way, the optical system 14
4a and 144b determine the laser light that travels straight and the laser light that reflects.

The laser beams traveling straight by the optical systems 144a and 144b are combined by the cylindrical lens 147a on or near the irradiation surface to form a rectangular beam.
The rectangular beams thus formed do not interfere with each other because they are emitted from different lasers. Further, since a plurality of laser beams having different energy distributions are combined on or near the irradiation surface, a rectangular beam having excellent energy distribution uniformity is formed.

On the other hand, the laser beams reflected by the optical systems 144a and 144b are cylindrical lenses 146a and 14c.
By 6b and the cylindrical lens 147b, they are combined on the irradiation surface or in the vicinity thereof to form a rectangular beam. The rectangular beams thus formed do not interfere with each other because they are emitted from different lasers. Further, since a plurality of laser beams having different energy distributions are combined on or near the irradiation surface, a rectangular beam having excellent energy distribution uniformity is formed.

Then, while irradiating a plurality of rectangular beams formed in this way, by moving relative to the object 108 to be irradiated in a direction indicated by 110 or a direction indicated by 111, for example, irradiation is performed. Irradiation can be performed on a desired region or the entire surface of the body 108. Moreover, since a plurality of rectangular beams are formed, the throughput can be improved.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

Further, in the present embodiment, two lasers are used and the number of divisions of the laser beam is two, but the number is not limited to this, and the number of rectangular beams formed is not limited to two.

In this embodiment, the first embodiment or the second embodiment is used.
Can be freely combined with.

[Embodiment 4] In this embodiment, an example of an optical system for splitting laser light oscillated from four lasers and superposing laser light having different energy distributions will be described with reference to FIG. To do.

Laser light is emitted from each of the lasers 151a to 151d. Here, the lasers 151a to 151
As d, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 151a to 151c may be converted into higher harmonics by a non-linear optical element.

In the present embodiment, a pulse oscillation YAG laser is used and converted into a second harmonic by a non-linear optical element. The second harmonic of the YAG laser is transmitted through the glass substrate or the quartz substrate, and is preferably used for irradiation from both sides of the substrate as in this embodiment.

Then, the respective emitted laser lights are beam expanders 152a to 152d, 153.
a to 153d are enlarged. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small, and may not be used depending on the size of the laser light and the like. Further, it is desirable that the cylindrical lenses 152a to 152d and 153a to 153d are made of synthetic quartz glass because a high transmittance can be obtained.
In addition, the cylindrical lenses 152a to 152d, 15
The coatings on the surfaces 3a to 153d are
It is desirable to use a material that can obtain a transmittance of 99% or more for the wavelength of the laser light used.

Beam expanders 152a to 152
The laser beams emitted from the laser beams d and 153a to 153d are the optical system 15 in which a mirror and a cylindrical lens are combined.
It is divided into two directions by 4a to 154d. Optical system 15
As for the laser light oscillated from the laser 151a by 4a, only the leftmost laser light of the four divisions goes straight, and the other laser light is reflected by the mirror and the damper 156a.
To reach. Of the laser light emitted from the laser 151b, only the second laser light from the left of the four splits goes straight by the optical system 154b, and the other area is reflected by the mirror and reaches the damper 156a. Optical system 154c
As a result, only the second laser light from the right of the four splits of the laser light emitted from the laser 151c goes straight, and the other laser light is reflected by the mirror and the damper 156.
reach c. The optical system 154d allows the laser 151d
In the laser light oscillated from, only the rightmost laser light of the four divisions goes straight, and the other laser light is reflected by the mirror and reaches the damper 156c. In this way, the laser light that travels straight and the laser light that is reflected are determined by the optical systems 154a to 154d.

Of course, after the respective laser beams are incident on the cylindrical lens array and divided, only the laser beam in a desired region can be extracted by the slit having the reflecting surface.

Although not shown, the laser light at the ends of the divided areas is shorter in the lengthwise direction than the laser light near the center, and therefore it is desirable to enlarge by a cylindrical lens or the like.

The laser beams passed through the optical systems 154a to 154d are combined by the cylindrical lenses 155a and 155c on or near the irradiation surface to form a rectangular beam. The rectangular beams thus formed do not interfere with each other because they are emitted from different lasers. Also,
Since a plurality of laser beams having different energy distributions are combined at or near the irradiation surface, a rectangular beam having excellent energy distribution uniformity is formed.

Then, while irradiating the rectangular beam thus formed, the irradiation target 108 is moved by moving relative to the irradiation target 108 in a direction indicated by 110 or a direction indicated by 111, for example. In, the desired area or the entire surface can be irradiated.

When a plurality of laser beams are combined from one side of the substrate at the same irradiation position, the respective optical paths are different, the beam is unnecessarily expanded due to the divergence angle of the laser beam, and the uniformity of energy distribution deteriorates. There are also things to do.
In the configuration of the present embodiment, since the optical path lengths of the respective laser lights to the irradiation surface are equal, such a problem does not occur.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

Further, in the present embodiment, four lasers are used and the division number of the laser light is four, but the number is not limited to this.

This embodiment can be freely combined with Embodiments 1 to 3.

[Embodiment 5] In this embodiment, an optical system for splitting laser light emitted from four lasers, superposing laser lights having different energy distributions, synthesizing them, and irradiating from both sides of the substrate. An example will be described with reference to FIG.

In FIG. 9, lasers 101a and 101
b, isolator 102a, 102b beam expander 103a, 104a or 103b, 104b,
Mirrors 105a, 105b, mirrors 106a, 106
The optical system including b, the irradiation target 108, and the stage 109 is the same as the configuration (FIG. 1) described in the first embodiment.

In this embodiment, a YLF laser is used as the laser and is converted into the second harmonic. Since the second harmonic of the YLF laser passes through the glass substrate and the quartz substrate,
It is preferably used when irradiation is performed from both sides of the substrate as in this embodiment. Further, the substrate can be partially annealed even at a wavelength that does not transmit, and therefore, it can be used in this embodiment.

The lasers 101c and 101d, the isolators 102c and 102d, and the beam expanders 103c and 1c having the same configuration as that of FIG.
04c or 103d, 104d, mirror 105c, 1
An optical system including 05d and mirrors 106c and 106d is arranged.

With such a structure, a rectangular beam can be emitted from both sides of the substrate. Then, while irradiating the rectangular beam thus formed, the irradiation target 1 is irradiated in a direction indicated by 110 or a direction indicated by 111, for example.
08, by moving relatively to 08
In, the desired area or the entire surface can be irradiated.

By irradiating from both sides of the substrate, the energy density can be increased. Further, when a plurality of laser beams are combined from one side of the substrate at the same irradiation position, the respective optical path lengths are different, the beam is unnecessarily expanded due to the divergence angle of the laser beam, and the uniformity of energy distribution decreases Sometimes. In the configuration of the present embodiment, since the optical path lengths of the respective laser lights to the irradiation surface are equal, such a problem does not occur.

When the semiconductor film is annealed using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

Further, in the present embodiment, four lasers are used and the number of laser light divisions is two, but the number is not limited to this.

This embodiment can be freely combined with Embodiments 1 to 4.

[Embodiment 6] In this embodiment, an example of an optical system for splitting laser light oscillated from four lasers and superimposing laser light having different energy distributions will be described with reference to FIGS. This will be described with reference to FIG.

Laser light is emitted from each of the lasers 131a to 131d. Here, the lasers 131a to 131
As d, a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser is used. The solid-state laser may be a continuous wave or pulsed YAG laser.
There are lasers, YVO ₄ lasers, YLF lasers, YAlO ₃ lasers, Y ₂ O ₃ lasers, glass lasers, ruby lasers, alexandrite lasers, Ti: sapphire lasers, etc., and the gas lasers are continuous wave or pulsed excimer lasers. , Ar laser, Kr laser, CO ₂ laser and the like, and examples of the metal laser include continuous oscillation or pulse oscillation helium cadmium laser, copper vapor laser, gold vapor laser and the like. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Further, the laser light emitted from the lasers 131a to 131d may be converted into higher harmonics by a non-linear optical element.

In this embodiment, a continuous wave YVO ₄ laser is used, and the second harmonic wave is converted by a non-linear optical element.
The beam diameter of the laser light is 2.25 mm, and the divergence angle is 0.35 mrad.

Although not shown, it is desirable to install an isolator. This is because the optical system in the present embodiment has a symmetrical arrangement, and thus each reflected light on the irradiation surface may adversely affect each other's lasers in the same manner as the return light.

Although not shown, a beam expander may be installed to expand the laser beam in the long and short directions. The beam expander is particularly effective when the shape of the laser light emitted from the laser is small.

The laser beams emitted from the lasers 131a to 131d are slits 132a to 132 having reflecting surfaces.
It is divided into two directions by d. However, the slit 132
Since a to 132d are installed at different positions with respect to the respective laser lights, only the laser lights at the different positions go straight. The situation will be described with reference to FIG. FIG. 4 shows the shape of laser light in a cross section perpendicular to the laser traveling direction. FIG. 4A shows laser light oscillated from the laser 132a, and the slit 132a allows the first laser light to oscillate.
Laser light goes straight, and the second to fourth laser lights are reflected and absorbed by the damper 135a. FIG. 4B shows laser light emitted from the laser 132b. The second laser light goes straight through the slit 132b, and the first, third, and fourth laser lights are reflected and absorbed by the damper 135a. To be done. FIG. 4C shows laser light oscillated from the laser 132c. The slit 132c causes the third laser light to travel straight, while the first, second, and fourth laser lights are reflected and absorbed by the damper 135c. To be done. FIG. 4D shows laser light oscillated from the laser 132d. The slit 132d causes the fourth laser light to go straight and
The third laser light is reflected and absorbed by the damper 135c. As described above, the slits 132a to 132d have a role of causing the laser beams having different energy distributions of the respective laser beams to go straight and reflecting the other laser beams.

Then, the laser light having passed through the slits 132a to 132d is obliquely incident on the convex lenses 134a to 134d. By doing so, the focal position shifts due to aberrations such as astigmatism, and the rectangular beam 106 can be formed on the irradiation surface or in the vicinity thereof.
In this embodiment, the convex lenses 134a and 134d have a radius of curvature of 7 mm, and the convex lenses 134b and 134c have a radius of curvature of 9 mm.
mm. As shown in FIG. 4, both ends of the laser light are shorter than those near the center. Therefore, by changing the radius of curvature, the length of the laser beam at the end of the original laser beam in the lengthwise direction is made larger than that at the center of the original laser beam, and the laser beam is synthesized on or near the irradiation surface. In this case, a rectangular beam with high uniformity can be obtained. In addition, when the laser light reaching the irradiation surface is the laser light at the end portion of the original laser light, a method of enlarging the length of the laser light in the lengthwise direction by a cylindrical lens or the like can be used.

FIG. 4 is a schematic diagram showing the shape of the laser beam formed on the irradiation surface by the optical system having the above-mentioned structure.
FIG. 25 shows the result obtained by the simulation as shown in (E). From Figure 25, 190μm ×
It can be seen that a rectangular beam of 950 μm is obtained. Since this rectangular beam is emitted from different lasers, no interference occurs. In addition, since a plurality of laser beams having different energy distributions are combined on the irradiation surface, a rectangular beam with excellent energy distribution uniformity is obtained.

Then, while irradiating the rectangular beam thus formed, the object 105 to be irradiated is moved relative to the object 105 to be irradiated in the direction indicated by 108 or the direction indicated by 109, for example. In, the desired area or the entire surface can be irradiated.

Although the number of lasers is 4 and the number of divisions is 4 in this embodiment, the number of lasers is not limited to these.

When the semiconductor film is annealed by using such a laser irradiation apparatus, the semiconductor film is crystallized,
Crystallinity can be improved to obtain a crystalline semiconductor film, and an impurity element can be activated.

[Embodiment 7] In this embodiment, a method for manufacturing an active matrix substrate will be described with reference to FIGS. In this specification, a substrate in which a pixel portion including a CMOS circuit and a driver circuit, a pixel TFT, and a storage capacitor is formed over one 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.
Further, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used, or a flexible substrate may be used. Since the present invention can form a plurality of rectangular beams having the same energy distribution, a large-area substrate can be efficiently annealed by the plurality of rectangular beams.

Then, 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. 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 film is formed on the base film.
The semiconductor film is formed into a film having a thickness of 25 to 200 nm (preferably 30 to 150 nm) by a known means (a sputtering method, an LPCVD method, a plasma CVD method or the like), and crystallized by a laser crystallization method. In the laser crystallization method, the semiconductor film is irradiated with laser light by using any one of Embodiments 1 to 6 or by freely combining these embodiments. The laser used is preferably a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser. As the solid-state laser, continuous oscillation or pulse oscillation YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ laser, glass laser,
There are a ruby laser, an alexandride laser, a Ti: sapphire laser, and the like, and the gas laser includes a continuous oscillation or pulse oscillation excimer laser, an Ar laser, and a K laser.
There are r lasers, CO ₂ lasers, and the like, and examples of the metal lasers include helium cadmium lasers, copper vapor lasers, and gold vapor lasers. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. Of course, not only the laser crystallization method but also other known crystallization methods (thermal crystallization method using RTA or furnace annealing,
It may be carried out in combination with a thermal crystallization method using a metal element that promotes crystallization). 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, the plasma CVD method is used,
A 50 nm amorphous silicon film is formed, and a thermal crystallization method and a laser crystallization method using a metal element that promotes crystallization are performed on the amorphous silicon film. Using nickel as the metal element,
After being introduced onto the amorphous silicon film by a solution coating method, 550
A first crystalline silicon film is obtained by performing heat treatment at 5 ° C. for 5 hours. Then, laser light emitted from a continuous oscillation YVO ₄ laser with an output of 10 W is converted into a second harmonic by a non-linear optical element, and then the optical system according to any one of Examples 1 to 6 or these Examples is used. A rectangular beam is formed by an optical system in which the above are combined and irradiated to obtain a second crystalline silicon film. The crystallinity is improved by irradiating the first crystalline silicon film with laser light to form the second crystalline silicon film. Energy density at this time is 0.01-100 MW
/ Cm ² (preferably 0.1 to 10 MW / cm ² ) is required. Then, the stage is moved relative to the laser light at a speed of about 0.5 to 2000 cm / s and irradiation is performed to form a crystalline silicon film. When a pulsed excimer laser is used, the laser energy density is 100 to 1000 mJ / cm ² (typically 200 to 800 m
J / cm ² ) is preferable. At this time, 50
~ 98% may be overlapped.

Of course, using the first crystalline silicon film, T
Although an FT can be manufactured, the crystallinity of the second crystalline silicon film is improved, which is preferable because the electrical characteristics of the TFT are improved. For example, when a TFT is manufactured using the second crystalline silicon film, the mobility is 500 to 600 cm ²
A high value of about / Vs is obtained.

The crystalline semiconductor film thus obtained is subjected to a patterning process using a photolithography method to form semiconductor layers 402 to 406.

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 is formed with a thickness of 110 nm by a plasma CVD method. Of course, the gate insulating film is not limited to the silicon oxynitride film, and other insulating films 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 thickness of 30 nm and a second conductive film 409 made of a W film having a thickness of 370 nm are stacked. 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.

Note that 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, and C are all used.
It may be formed of an element selected from u, Cr, and 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, A
A gPdCu alloy may be used.

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. 12B) In this embodiment, as the first etching condition, ICP (Inductively Coupled Plasma:
(Inductively coupled plasma) etching method, CF ₄ , Cl ₂ and O ₂ are used as etching gases, the flow rate ratio of each gas is set to 25:25:10 (sccm), and the coil type electrode is applied at a pressure of 1 Pa. RF (13.56 MHz) power of 500 W is applied to the substrate to generate plasma for 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. RF (13.56 MHz) power of 500 W is applied to generate plasma and etching is performed for about 30 seconds. 20W RF (13.56MH) on the substrate side (sample stage)
z) Apply power and apply a substantially negative self-bias voltage. 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.

Then, a second etching process is performed without removing the resist mask. Here (Fig. 12 (C)), using CF _4, Cl ₂ and O ₂ as an etching gas, to selectively etch the W film. 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
The second shape conductive layer 428 that is hardly etched
~ 433 is formed.

Then, the first doping process is performed without removing the resist mask, and the impurity element imparting n-type is added 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 / c.
m ² and the accelerating 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
Serves as a mask for the impurity element imparting n-type, and impurity regions 423 to 427 are formed in a self-aligned manner. In the impurity regions 423 to 427, 1 × 10 ¹⁸ to 1 × 10 ²⁰ /
An impurity element imparting n-type is added within the concentration range of 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. First conductive layers 429a, 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. 13B) At the time of the fourth doping process, the semiconductor layers forming the n-channel TFTs are covered with resist masks 450a to 450c. By the first to third doping processes, phosphorus is added to the impurity regions 453, 454, 459, and 460 at different concentrations, and the concentration of the impurity element imparting p-type is 1 × in any of the regions. 1
^By performing the doping process so as to have a concentration of 0 ^{19 to} 5 × 10 ²¹ atoms / cm ³ , there is 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. 13C, laser light is irradiated to recover the crystallinity of the semiconductor layers and activate the impurity elements added to the respective semiconductor layers. Laser activation is performed by irradiating the semiconductor film with laser light by using any one of Embodiments 1 to 6 or by freely combining these embodiments. The laser used is preferably a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser. As the solid-state laser, continuous oscillation or pulse oscillation YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, Y ₂ O ₃ laser glass laser,
There are a ruby laser, an alexandride laser, a Ti: sapphire laser, and the like, and the gas laser includes a continuous oscillation or pulse oscillation excimer laser, an Ar laser, and a K laser.
There are r lasers, CO ₂ lasers, and the like, and examples of the metal lasers include helium cadmium lasers, copper vapor lasers, and gold vapor lasers. The excimer laser is usually pulsed, but there is also a theory that continuous oscillation is possible in principle. A continuous wave excimer laser can also be applied to the present invention. At this time, if using a continuous wave laser, the energy density of the laser beam is about 0.01 to 100 MW / cm ² (preferably 0.01~10MW / cm ²⁾ is required, with respect to the laser beam Relative substrate 0.5-2000
Move at a speed of cm / s. If a pulsed laser is used, the laser energy density is 50 to
It is desirable to set it to 1000 mJ / cm ² (typically 50 to 500 mJ / cm ² ). At this time, the laser beams may be overlapped by 50 to 98%. Note that a thermal annealing method, a rapid thermal annealing method (RTA method), or the like can be applied in addition to the laser-neal method.

Further, activation may be performed before forming the first interlayer insulating film. However, when the wiring material used is weak against heat, activation is performed after forming an interlayer insulating film (insulating film containing silicon as a main component, for example, a silicon nitride film) to protect the wiring and the like as in this embodiment. It is preferable to carry out a chemical treatment.

Then, heat treatment (at 300 to 550 ° C. 1 to
Hydrogenation can be performed by performing 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 second interlayer insulating film having irregularities (not shown) is formed on the surface to form irregularities on the surface of the pixel electrode. 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 is the wiring and the TFT.
It may be appropriately provided on the substrate in the pixel portion region other than the 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 14)

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 433a and 433b) 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 is further electrically connected to the semiconductor layer that functions as one electrode forming the 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 which functions as a source region or a drain region.
The p-channel TFT 502, which is connected to the n-channel TFT 501 with an electrode 466 to form a CMOS circuit, has a channel forming region 445, a high-concentration impurity region 453 which functions as a source region or a drain region, and a low-concentration impurity region 454. is doing. In addition, n-channel TF
T503 has a channel formation region 443, a low-concentration impurity region 442 (GOLD region) overlapping with the first conductive layer 430a which forms part of a gate electrode, and a high-concentration impurity region 456 which functions as a source or drain region. ing.

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 which functions as a source region or a drain region. There is. In the semiconductor layer functioning as one electrode of the storage capacitor 505, an impurity element imparting n-type conductivity and p
An impurity element that imparts a mold is added. Storage capacity 5
05 is an electrode (432a) using the insulating film 416 as a dielectric.
And 432b) and a semiconductor layer.

In the pixel structure of this 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 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 parts corresponding to those in FIGS. A chain line AA ′ in FIG. 14 is a chain line AA ′ in FIG.
It corresponds to the cross-sectional view cut at. Further, a chain line BB ′ in FIG. 14 corresponds to a sectional view taken along a chain line BB ′ in FIG. 15.

[Embodiment 8] In this embodiment, a process of manufacturing a reflective liquid crystal display device from the active matrix substrate manufactured in Embodiment 7 will be described below. 16 for the explanation.
To use.

First, according to the fifth embodiment, after obtaining the active matrix substrate in the state of FIG. 14, an alignment film 567 is formed on at least the pixel electrode 470 on the active matrix substrate of FIG. 14, 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, a 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.
5 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, the number of steps can be reduced by forming the light-shielding portion formed of the stacked colored layers so as to shield the gaps between the pixels without forming a light-shielding layer such as a black matrix.

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 driving 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. 16 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 has a TFT manufactured using a semiconductor film uniformly annealed by a laser beam having a uniform energy distribution. The characteristics and reliability can be sufficient. 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 7.

[Embodiment 9] In this embodiment, a TFT for manufacturing the active matrix substrate shown in Embodiment 7
An example in which a light-emitting device is manufactured by using the manufacturing method of will be described. In the present 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 including a TFT on the display panel. is there. Note that the light-emitting element has a luminescence (Elec
It has a layer (light emitting layer) containing an organic compound for which tro luminescence is obtained, an anode layer, and a cathode layer. 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). Alternatively, it includes both luminescence.

In the present specification, all the layers formed between the anode and the cathode in the light emitting device are defined as the organic light emitting layer. The organic light emitting layer 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 layer, 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 are provided. 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. 17 is a sectional view of the light emitting device of this embodiment. 17, 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 driving circuit provided on the substrate 700 is shown in FIG.
4 CMOS circuit is used. 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.

The wirings 701 and 703 function as a source wiring of the CMOS circuit, and 702 functions as a drain wiring.
The wiring 704 is connected to the source wiring 708 and the switching T.
The wiring 705 functions as a wiring that electrically connects the source region of the FT, and the wiring 705 is connected to the drain wiring 709 and the switching T.
It functions as a wiring that electrically connects the drain region of the FT.

The current control TFT 604 has the p-type structure shown 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 current control TFT 604.
Source wiring (corresponding to a current supply line) of 707
Is a drain wiring of the current control TFT 604, and is an electrode that is electrically connected to the pixel electrode 711 by being overlapped on the pixel electrode 711.

Reference numeral 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 layer that is formed later is very thin, the light emitting failure may occur due to the existence of the step. Therefore, it is desirable to flatten the light emitting layer before forming the pixel electrode so that the light emitting layer 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 layer 713 is formed on the pixel electrode 711. Although only one pixel is shown in FIG. 17, light emitting layers corresponding to respective colors 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 injection layer, and a 7-nm light emitting layer 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 layer, and it is not necessary to limit to this. The light emitting layer (charge transporting layer or charge injecting layer) may be freely combined to form a light emitting layer (a layer for emitting light and for moving carriers therefor). 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.

When the cathode 714 is formed, the light emitting element 715 is completed. 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 a passivation film, and a carbon film, especially D
It is effective to use an LC 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 layer 713 having low heat resistance. In addition, the DLC film has a high blocking effect on oxygen and can suppress oxidation of the light emitting layer 713. Therefore, it is possible to prevent the problem that the light emitting layer 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 this embodiment, the cover material 718 is a glass substrate, a quartz substrate, a plastic substrate (including a plastic film), or a flexible substrate having a carbon film (preferably a DLC film) formed on both sides. Besides carbon film, aluminum film (AlON, Al
N, AlO, etc.), SiN, etc. can be used.

Thus, the light emitting device having the structure as shown in FIG. 17 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.
FT 601, p-channel TFT 602, switching TFT (n-channel TFT) 603 and current control T
An FT (p-channel TFT) 604 is formed.

Further, as described with reference to FIG. 17,
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 configurations of the pixel portion and the driving circuit are shown in the present embodiment, a signal dividing circuit, a D / A converter, an operational amplifier, a 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 which is uniformly annealed by a laser beam having a uniform energy distribution,
The operating characteristics and reliability of the light emitting device may be sufficient. Then, such a light emitting device can be used as a display portion of various electronic devices.

This embodiment can be freely combined with Embodiments 1 to 7.

[Embodiment 10] 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 equipment 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. 18, 19 and 20.

FIG. 18A 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. By applying the semiconductor device manufactured according to the present invention to the display portion 3003,
The personal computer of the present invention is completed.

FIG. 18B 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 video camera of the present invention is completed by applying the semiconductor device manufactured by the present invention to the display portion 3102.

FIG. 18C 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 mobile computer of the present invention is completed by applying the semiconductor device manufactured by the present invention to the display portion 3205.

FIG. 18D shows a goggle type display, which includes a main body 3301, a display section 3302 and an arm section 330.
Including 3 etc. The goggle type display of the present invention is completed by applying the semiconductor device manufactured by the present invention to the display portion 3302.

FIG. 18E shows a player that uses a recording medium (hereinafter, referred to as a recording medium) in which a program is recorded, and includes 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
digital Versatile Disc), CD
It is possible to play music, watch movies, play games, and use the internet. The recording medium of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3402.

FIG. 18F 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. By applying the semiconductor device manufactured according to the present invention to the display portion 3502, the digital camera according to the present invention is completed.

FIG. 19A shows a front type projector including a projection device 3601, a screen 3602 and the like. The projection device 36 is a semiconductor device manufactured by the present invention.
01 is applied to the liquid crystal display device 3808 which constitutes a part of No. 01 and other drive circuits, the front type projector of the present invention is completed.

FIG. 19B shows a rear type projector including a main body 3701, a projection device 3702 and a mirror 370.
3, screen 3704 and the like. By applying the semiconductor device manufactured by the present invention to the liquid crystal display device 3808 which forms a part of the projection device 3702 and other drive circuits, the rear projector of the present invention is completed.

Note that FIG. 19C is a diagram showing an example of the structure of the projection devices 3601 and 3702 in FIGS. 19A and 19B. 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 a phase difference, an IR film, or the like in the optical path indicated by an arrow in FIG. 19C. Good.

FIG. 19D is a diagram showing an example of the structure of the light source optical system 3801 in FIG. 19C. 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. The light source optical system shown in FIG. 19D 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. 19 shows a 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. 20A 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 mobile phone of the present invention is completed by applying the semiconductor device manufactured according to the present invention to the display portion 3904.

FIG. 20B 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. By applying the semiconductor device manufactured by the present invention to the display portions 4002 and 4003, the portable book of the present invention is completed.

FIG. 20C shows a display, which includes a main body 4101, a support base 4102, a display portion 4103 and the like.
The display of the present invention is completed by applying the semiconductor device manufactured by the present invention to the display portion 4103. The display of the present invention is particularly advantageous when it has a large screen, and has a diagonal of 10 inches or more (particularly 30 inches or more).
Display is advantageous.

As described above, the applicable range of the present invention is so wide that it can be applied to electronic devices in various fields. Further, the electronic device of this embodiment can also be realized by using a configuration including a combination of the first to eighth or ninth embodiments.

[0220]

By adopting the structure of the present invention, the following basic significance can be obtained. (A) It is possible to form a laser beam having a very uniform energy distribution on the irradiation surface or a plane in the vicinity thereof. Therefore, the object to be irradiated can be annealed uniformly. (B) Since laser beams emitted from different lasers are combined, no interference occurs. This is particularly effective when using a laser with high coherence. (C) It is possible to improve throughput. This is particularly effective in the case of a large area substrate. (D) In addition to satisfying the above advantages, in a semiconductor device represented by an active matrix type liquid crystal display device,
It is possible to improve the operating 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 an optical system of the present invention.

FIG. 2 is a diagram showing an example of a state of laser light split by the optical system of FIG.

FIG. 3 is a diagram showing an example of an optical system of the present invention.

4 is a diagram showing an example of a state of laser light split by the optical system of FIG.

5 is a diagram showing an example of the shape of a rectangular beam formed on the irradiation surface by the optical system of FIG.

FIG. 6 is a diagram showing an example of an optical system of the present invention.

FIG. 7 is a diagram showing an example of an optical system of the present invention.

FIG. 8 is a diagram showing an example of an optical system of the present invention.

FIG. 9 is a diagram showing an example of an optical system of the present invention.

FIG. 10 is a diagram showing an example of a conventional optical system.

FIG. 11A is a diagram showing an example of the energy density distribution of laser light formed by a conventional optical system. FIG. 11B is a diagram showing an example of annealing a large area substrate with the laser light shown in FIG.

FIG. 12 is a cross-sectional view showing a manufacturing process of a pixel TFT and a driver circuit TFT.

FIG. 13 is a cross-sectional view showing a manufacturing process of a pixel TFT and a driver circuit TFT.

14A to 14C are cross-sectional views illustrating a manufacturing process of a pixel TFT and a driver circuit TFT.

FIG. 15 is a top view showing a configuration of a pixel TFT.

FIG. 16 is a cross-sectional view of an active matrix liquid crystal display device.

FIG. 17 is a cross-sectional structure diagram of a driver circuit and a pixel portion of a light emitting device.

FIG. 18 illustrates an example of a semiconductor device.

FIG. 19 illustrates an example of a semiconductor device.

FIG. 20 illustrates an example of a semiconductor device.

FIG. 21 is a diagram showing an example of an optical system of the present invention.

22 is a diagram showing an example of a state of laser light split by the optical system of FIG.

FIG. 23 is a diagram for obtaining an incident angle θ of laser light with respect to an irradiation target.

FIG. 24 is a diagram showing an example of an optical system of the present invention.

FIG. 25 is a diagram showing an example of the shape of laser light formed on the irradiation surface according to the present invention.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5F052 AA02 BA01 BA02 BA04 BA14                       BA15 BA18 BB01 BB02 BB05                       BB06 BB07 DA01 DA03 DA04                       DA06 DB02 DB03 DB07 FA06                       JA01 JA04                 5F072 AB01 AB15 AB20 JJ08 JJ20                       KK09 KK12 KK30 MM07 MM08                       QQ02 SS06 SS10 YY08                 5F110 AA01 BB02 BB04 CC02 DD01                       DD02 DD03 DD05 DD13 DD14                       DD15 DD17 EE01 EE02 EE03                       EE04 EE06 EE09 EE14 EE23                       EE28 EE44 EE45 FF02 FF04                       FF28 FF30 FF36 GG01 GG02                       GG13 GG24 GG25 GG32 GG33                       GG43 GG45 GG47 HJ01 HJ04                       HJ12 HJ13 HJ23 HL01 HL02                       HL03 HL04 HL06 HL11 HM15                       NN03 NN04 NN22 NN27 NN34                       NN35 NN71 NN73 PP01 PP02                       PP03 PP04 PP05 PP06 PP07                       PP10 PP29 PP34 QQ04 QQ11                       QQ23 QQ24 QQ25

Claims (14)

[Claims] 1. A plurality of lasers, a means for cutting a plurality of first laser light spots oscillated from the plurality of lasers, and dividing the plurality of second laser light spots into a plurality of second laser light spots, respectively. Means for selecting one spot from each of the second laser light spots and combining them in the same area on the irradiation surface for each of the one laser light spots. 2. A plurality of lasers, a means for cutting a plurality of first laser light spots oscillated from the plurality of lasers, and dividing the spots into a plurality of second laser light spots, respectively. Each of the one spot of the laser light, a means for selecting one spot of the laser light having a different energy distribution from the spot of the second laser light and combining them in the same area on the irradiation surface. Laser irradiation device characterized by. 3. The laser irradiation device according to claim 1 or 2, wherein the shape of the laser light formed by combining in the same area on the irradiation surface is a linear shape. 4. The method according to any one of claims 1 to 3,
The laser irradiation device is characterized in that the synthesizing means is one or more selected from a mirror and a cylindrical lens. 5. A plurality of lasers, means for cutting a plurality of first laser light spots oscillated from the plurality of lasers, and dividing the plurality of second laser light spots into a plurality of second laser light spots, respectively. Irradiation surface by selecting one from each of the spots of the second laser light emitted from the convex lens in each of the plurality of first laser light spots and the convex lens obliquely installed with respect to the second laser light. In the same area, the irradiation surface is installed so that the laser light that has passed through the convex lens is obliquely incident on the irradiation surface, and the laser beam on the irradiation surface by the convex lens. The laser irradiation device is characterized in that the light is formed in a linear shape. 6. A plurality of lasers, means for cutting a plurality of first laser light spots oscillated from the plurality of lasers, and dividing the spots into a plurality of second laser light spots, respectively. Laser light having different energy distributions from the spots of the second laser light emitted from the convex lens in each of the convex lens installed obliquely with respect to the second laser light and the plurality of spots of the first laser light. Means for selecting the spots one by one and synthesizing them in the same area on the irradiation surface, and the irradiation surface is installed so that the laser light passing through the convex lens is obliquely incident on the irradiation surface. The laser irradiation device is characterized in that the convex lens forms a linear shape of the laser light on the surface to be irradiated. 7. The irradiation target according to claim 5 or 6, wherein the beam length of the laser light incident on the irradiation target placed on the substrate is w and the thickness of the substrate is d. The laser irradiation apparatus is characterized in that an incident angle θ of the laser light incident on the surface satisfies θ ≧ arctan (w / (2 × d)). 8. The method according to claim 5, wherein
Incident angle θ of the laser light incident on the irradiation target
Is a Brewster's angle. 9. The method according to any one of claims 1 to 8,
The laser irradiation device is characterized in that the dividing means is one or more selected from a slit, a mirror, a prism, a cylindrical lens, and a cylindrical lens array. 10. The laser irradiation apparatus according to claim 1, wherein the laser is a continuous wave or pulsed solid-state laser, a gas laser, or a metal laser. 11. The laser according to claim 1, wherein the laser is a continuous wave or pulsed YAG laser.
A laser irradiation device characterized by being a kind selected from a laser, a YVO ₄ laser, a YLF laser, a YAlO ₃ laser, a Y ₂ O ₃ laser, a glass laser, a ruby laser, an alexandrite laser, and a Ti: sapphire laser. 12. The laser irradiation device according to claim 1, wherein the laser is one kind selected from Ar laser, Kr laser, and CO ₂ laser. 13. The laser irradiation device according to claim 1, wherein the laser is one kind selected from a helium cadmium laser, a copper vapor laser, and a gold vapor laser. 14. The laser irradiation apparatus according to claim 1, wherein the laser light is converted into a harmonic by a non-linear optical element.