JP2001242413A - Optical system and laser irradiating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the aberration of a spherical lens and to uniformize the energy distribution of a linear laser. SOLUTION: The cylindrical lens is divided by the plane parallel to the generatrix and the optical axis. By changing the height from the irradiated surface of the divided individual lens, the difference in the focal length in the lens is corrected to decrease the aberration. The energy distribution of the linear laser thereby becomes uniform. The method is used also not only as the linear laser optical system but as a method of reducing the aberrations of the lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to reduce aberrations of an optical system at a low cost by a simple method. By applying the present invention to a laser optical system for crystallizing a semiconductor film, uniform crystallization can be performed in the plane of the substrate. The present invention provides a technique that can be easily applied to an optical system of a linear laser crystallization apparatus using a cylindrical lens.

[0002]

2. Description of the Related Art In recent years, an amorphous semiconductor film or a crystalline semiconductor film (a semiconductor film which is not a single crystal but has a crystallinity such as polycrystal or microcrystal) formed on an insulating substrate such as glass, Techniques for performing laser annealing on a single crystal semiconductor film to crystallize or improve crystallinity have been widely studied. As the semiconductor film, a silicon film is often used.

The glass substrate is inexpensive, has good processability, and has an advantage that a large-area substrate can be easily manufactured, as compared with a quartz substrate which has been often used in the past. For this reason, the above research has been actively conducted. A laser is preferably used for crystallization because the melting point of the glass substrate is low. The laser can apply high energy only to the non-single-crystal semiconductor film without changing the temperature of the substrate so much.

Since a crystalline silicon film formed by performing laser annealing has high mobility, a thin film transistor (TFT) is formed using the crystalline silicon film, and, for example, is formed on a single glass substrate. It is widely used in monolithic liquid crystal electro-optical devices for producing TFTs for driving pixels and driving circuits. Since the crystalline silicon film is made of many crystal grains, it is called a polycrystalline silicon film or a polycrystalline semiconductor film.

[0005] A pulsed laser beam having a large output, such as an excimer laser, is processed by an optical system so as to form a square spot of several cm square or a linear shape of 10 cm or more on the surface to be irradiated. The method of performing laser annealing by scanning with a laser beam (moving the irradiation position of the laser beam relative to the irradiated surface) is preferable because mass productivity is good and industrially excellent. used.

In particular, when a linear laser beam is used,
Unlike when using a spot-shaped laser beam that requires front-back, left-right scanning, the laser beam can be applied to the entire irradiated surface by scanning only in the direction perpendicular to the line direction of the linear laser beam. , High mass productivity can be obtained. Scanning is performed in a direction perpendicular to the line direction because it is the most efficient scanning direction. Due to this high mass productivity, the use of a linear laser beam obtained by processing a laser beam of a pulsed excimer laser with an appropriate optical system is becoming mainstream for laser annealing.

FIGS. 18 and 19 show an optical system for forming a linear laser beam, which forms an image of a laser beam on a substrate by using a cylindrical lens. For the optical system, a cylindrical lens and a cylindrical array lens are used. As shown in FIG. 22, a cylindrical lens 1201
Has a curved surface in the width direction and no curved surface in the length direction.
Thus, the outgoing light 1203 is focused on the incident light 1202 in the width direction by the refraction effect of the lens, but the light is not refracted in the length direction.

A commercially available linear laser beam has a length 110 in the short direction of 0.2 to 1.0 mm.
And the length 111 in the longitudinal direction is 100 to 300 mm. To obtain such a linear laser beam, a lens design according to geometrical optics may be performed. In particular, in an optical system for forming a linear laser, it is necessary to pay attention to aberration when light is imaged in a short direction in order to converge on a narrow laser beam.

The role of each lens shown in FIGS. 18 and 19 will be described below. FIG. 19A shows the optical system of FIG. 18 viewed from the side, and FIG.
This is shown in 9 (2).

FIG. 19A will be described below. The laser light emitted from the laser irradiation device 101 is split by the cylindrical array lens 102 in the short direction of the linear laser. Here, since four cylindrical lenses are arranged in an array, the beam is divided into four beams.

The laser divided in the short direction passes through the cylindrical lens 103, but the cylindrical lens 1
From the shape of 03, the lens is not refracted in the short direction. Then, light is incident on the cylindrical lens 106 provided near the substrate by the cylindrical lens 104 having a relatively long focal length. Then, the light is combined into one by the cylindrical lens 106 and is irradiated on the irradiation surface 108. Thereby, the energy in the short direction of the linear laser beam is made uniform, and the length in the short direction is determined. Reference numeral 109 denotes a light beam of the laser light of the optical system.

FIG. 19B will be described below. The propagation of light imaged in the longitudinal direction of the linear laser will be described. The laser beam is a cylindrical array lens 10
3 divides the beam into seven beams in the longitudinal direction.

The laser divided in the longitudinal direction of the linear laser passes through the cylindrical lens 104, but is not refracted in the longitudinal direction due to the shape of the cylindrical lens 104. Then, the light enters the surface to be irradiated by the cylindrical lens 105 having a long focal length. Reference numeral 112 denotes a light beam of the laser light of the optical system.

As shown in FIG. 19A, two sets of lenses, such as cylindrical lenses 104 and 106, are used to condense a beam in the short direction of a linear laser.
That is, the laser beam is condensed at the focal point 113 of the cylindrical lens 104 and becomes one linear shape. But focus 11
The laser beam focused at 3 is a linear beam whose width in the short direction is large. After being condensed at the focal point 113, the laser light is further divided into four linear lasers and enters the cylindrical lens 106. Then, after being condensed by the cylindrical lens 106, the laser beam spreads, and the laser beam enters the irradiation surface 108. The laser light on the surface to be illuminated is elongated compared to the linear laser light imaged at the focal point 113 of the cylindrical lens 104.

When the longitudinal direction of the linear laser is lengthened, even a substrate having a large area can be uniformly irradiated without a laser irradiation seam. However, in order to increase the longitudinal direction of the linear laser beam and at the same time obtain a laser energy density sufficient to crystallize a non-single-crystal semiconductor film, the width of the linear laser beam in the short direction must be reduced. No. Usually, the width of the linear laser in the short direction needs to be 0.2 mm to 1.0 mm in relation to the output of the laser.

In FIG. 20, doublet cylindrical lenses 201 and 202 are used instead of the cylindrical lens 106 in the optical system shown in FIGS. By combining two lenses to use as a condensing lens, the aberration of the lens is significantly reduced.
FIG. 20A is a side view of the optical system, and the laser light is converged in the short direction of the linear laser. FIG. 20 (2) is a top view of the optical system, in which laser light is converged in the longitudinal direction of the linear laser. The description of the reference numerals 101 to 112 in FIG.
Same as 8 and 19.

[0017]

For example, a lens made of an acrylic resin can be molded by heating and subjected to aspherical processing. However, a lens for a laser having a short wavelength is made of quartz having a high melting point, and it is difficult to perform aspheric processing.

In an ideal lens, light incident on the lens forms an image at one point regardless of the incident position. However, a real lens has some error compared to an ideal lens. The amount of error from the ideal lens is called aberration.

One of the problems caused by the spherical lens is spherical aberration. FIG. 21 shows the spherical aberration.
The figure is a sectional view showing a light beam passing through a lens. Lens 11
The light 1101 incident near the optical axis 04 and the light 1102 incident at a position away from the optical axis and the light 1103 incident near the end of the lens have different focal points. Thereby, the irradiated surface 11
The image formed at 05 is not fixed at one point but has a spread.

To prevent spherical aberration, it is necessary to change the radius of curvature of the lens within the lens, but it is very difficult to produce an aspherical lens for short wavelengths.

The cylindrical lens 10 shown in FIGS.
In the shape of No. 6 and the arrangement in the laser optical system, the main problem is spherical aberration. Since it is a laser optical system, chromatic aberration does not pose a major problem even if there is an energy distribution depending on the wavelength of the laser light.

In the optical system shown in FIGS. 18 and 19, a cylindrical lens 106 composed of one lens is used as a lens for condensing a linear laser beam in a short direction. In this optical system, the energy profile in the short direction of the linear laser beam obtained as shown in FIG. 8A was a Gaussian distribution, that is, a non-uniform distribution. In the graph of FIG. 8, the horizontal axis indicates the short direction of the linear laser, and the vertical axis indicates energy.

The cause of the energy profile having a Gaussian distribution is that the cylindrical lens 1 shown in FIGS.
06 aberration. The cylindrical lens 106
The laser beam once divided into a plurality of light beams serves to combine them on a surface to be irradiated. However, due to the aberration of the lens, the divided individual light beams do not completely become one on the irradiated surface. Thereby, it has an energy profile having a Gaussian distribution spreading in the short direction.

In the optical system shown in FIGS. 18 and 19, since the cylindrical lens 104 has a long focal length, aberration of the lens is small. The problem with optical systems is the cylindrical lens 1
06 is the aberration. The laser beam width is practically 0.
It is in the range of 2 to 1.0 mm, and it is important to suppress the aberration of the cylindrical lens 106 in order to keep the laser beam in such a range.

However, when the optical system shown in FIGS. 18 and 19 is employed, the energy distribution of the linear laser beam becomes non-uniform. Therefore, when the linear laser beam was irradiated on the silicon film while scanning, the laser energy became uneven in the irradiated surface, and the laser irradiation trace remained as a stripe pattern on the silicon film.

On the other hand, in an optical system as shown in FIG. 20, a doublet cylindrical lens constituted by two cylindrical lenses 201 and 202 is used as a condensing lens. This is an improvement over the drawbacks of the optical system shown in FIGS. In the doublet cylindrical lens, the spherical aberration of the condensing lens is significantly reduced by combining two cylindrical lenses.

In the optical system using the doublet cylindrical lens, the energy profile of the obtained linear laser beam in the short direction became closer to a rectangular distribution. That is, the distribution became more uniform as shown in FIG. 8B. The linear laser beam forming optical system generally used at present is very close to the configuration shown in FIG. When the obtained linear laser beam is irradiated on the silicon film while scanning, and the entire silicon film is crystallized, laser irradiation traces are less likely to remain on the silicon film, and a more uniform in-plane polycrystal is obtained. A silicon film is obtained.

However, in the configuration using the doublet cylindrical lens, the laser optical system is expensive because two sets of cylindrical lenses are used. In order to adjust the optical axis, it is necessary to adjust the height of the two cylindrical lenses and the elevation angle. Therefore, a desired beam can be obtained only after a highly skilled operator makes adjustment.

As described above, when the cylindrical lens 106 is used for focusing a laser beam as shown in FIGS. 18 and 19, the cylindrical lens is inexpensive, but the energy distribution of the linear laser is not uniform due to lens aberration. Become. When the silicon film was crystallized, non-uniformity of the energy distribution appeared uneven and the laser irradiation trace remained as a stripe pattern on the silicon film.

When the doublet cylindrical lens 201 is used for focusing a laser beam as shown in FIG. 20, the optical system becomes expensive, and it is difficult to align the optical axes of the two lenses.

[0031]

FIG. 5 shows a feature of the present invention. FIG. 5 is a sectional view showing a light beam passing through the lens. A feature of the present invention is that the lens is divided into individual lenses 501 to 50.
3, the height of each lens from the irradiated surface 507 was changed. The height refers to the distance between the rear surface of the lens, that is, the surface from which light is emitted and the surface to be irradiated. 50 incident light
4 to 506. The lights 504 to 506 that have entered the individual lenses 501 to 503 are condensed in front of the surface to be irradiated, and then spread and enter the surface to be irradiated 507. Lenses 502 and 50 farther from the optical axis than lens 501 near the optical axis
The third is closer to the irradiated surface 507. Thereby, the aberration of the spherical lens is reduced, and the spread of the light incident on the lenses 501 to 503 on the irradiated surface is suppressed. The edges of the six beams converged on the surface to be irradiated substantially overlap each other. The divided beams form lenses 501 to 5
The present invention is effective when the light is incident on the light emitting element 03.

FIG. 1 shows an example in which the lens of the present invention is used in a laser optical system. The optical system shown in FIG. 1 is characterized in that a cylindrical lens 106 as a condensing lens is divided into a plurality of parts by a plane parallel to the generating line and a plane parallel to the optical axis. FIG. 1 illustrates an optical system for condensing light in a short direction of a linear laser, which is compared with FIG. 19A of a conventional example. One fragment of the divided lens will be referred to as divided cylindrical lenses 203 and 204, respectively. By dividing the cylindrical lens and changing the distance from the irradiated surface, the light passing through each cylindrical lens is condensed into an elongated linear shape. The use of a micrometer for the mechanism for moving the lens facilitates adjustment.

Since the distance between the laser beams incident on the cylindrical lens 106 of the optical system shown in FIGS. 18 and 19 is sufficiently large, the lens can be easily divided in consideration of the incident position of the laser beam.

For the division of the lens, a scriber for cutting the glass by rotating a wheel of diamond stone or cemented stone on the glass surface may be used.

A linear laser beam enters the divided cylindrical lens one by one. In the condensing lens shown in FIG. 1, two laser beams are made incident on the central lens. However, it can be understood that this is sufficient considering the symmetry of the system.

When the number of beams split by the cylindrical array lens 102 is an odd number, only one beam is incident on the central lens of the condensing lens.

By individually adjusting the divided lenses, the energy profile in the short direction of the obtained linear laser beam can be changed. For example, one of the divided lenses 301 is moved in the direction of the arrow in FIG. The laser beam that has passed through the lens is
At the same time as the beam width changes on the irradiated surface, the imaging position moves in the beam width direction. By utilizing this property and adjusting the height of each of the divided lenses, it is possible to form an image while suppressing the spread of the laser beam, and the profile of the laser beam is as shown in FIG. 8C. be able to.

The profile of the laser beam shown in FIG. 8C has a certain energy distribution in the surface to be irradiated, and deviates from an ideal rectangular energy profile. However, regarding the energy homogeneity of the laser beam, the cylindrical lens 106 shown in FIGS.
Is improved compared to However, as compared with the energy profile of FIG. 8B in the optical system using the doublet cylindrical lens as shown in FIG. 20, the energy uniformity is still poor.

Another embodiment of the present invention with further improved energy homogeneity is shown in FIG. The feature of the optical system shown in FIG. 2 is that the overlapping of the beams on the irradiated surface is more matched by making the focal lengths of the divided focusing lenses different from each other. As a method of obtaining divided lenses having different focal lengths, there is a method of dividing and combining cylindrical lenses having different radii of curvature. The focal length of the divided lens is indicated by the focal length of the spherical lens before division.

The divided cylindrical lens 20 shown in FIG.
5, 206, and 207 have different focal lengths, and the center lens has a larger radius of curvature and a longer focal length. The radius of curvature is shorter and the focal length is shorter at the end lens. The shorter the lens with the shorter focal length, the more the irradiated surface 108
Close to. The use of a micrometer for the mechanism for moving the lens facilitates adjustment.

Thus, the homogeneity of the beam is dramatically improved. This uniformity is better than the optical system of FIG.

The structure of the present invention is particularly effective for an optical system of a linear laser beam. Since the distance between the laser beams incident on the cylindrical lens 106 shown in FIGS. 18 and 19 is sufficiently large, the lens can be easily processed in consideration of the incident position of the laser beam. The present invention is easier to apply than an optical system in which light is incident on the entire surface of the lens.

In the present invention, a spherical lens is divided to reduce spherical aberration. The present invention is effective for a lens made of a material having a high melting point which is difficult to aspherically process. It is also effective for an optical system in which individual beams are split and incident on a lens.

The present invention is applicable not only to a cylindrical lens forming linear light but also to reducing spherical aberration of a lens forming point light such as an objective lens of a microscope.

This will be described with reference to FIGS. First, FIG.
As shown in the top view of (1), the lenses may be cut along planes orthogonal to each other. In FIG. 6, a quartz plano-convex lens 601 having a constant radius of curvature is divided. The plano-convex lens 601 has two scribe lines 6 in the vertical direction and two in the horizontal direction.
03 is divided

FIG. 7 shows a method of forming a split beam. Laser light 610 is emitted from the light source 609. Then, a cylindrical array lens 607 in which three cylindrical lenses are arranged in an array and a cylindrical array lens 608 in which three cylindrical lenses are arranged in an array are combined in a direction orthogonal to each other. As a result, FIG.
Are divided into nine laser beams 602 shown in FIG.

The plano-convex lens divided as shown in the sectional view of FIG. 6 (2) is arranged at a height closer to the irradiated surface as the beam incident position is farther from the optical axis of the lens. FIG.
In (2), a number is shown for each lens segment. The closer the position of the laser beam 602 incident on each lens segment to the optical axis is, the larger the number shown on the lens segment is. That is, the number is a relative comparison of the height 605 from the irradiated surface 604, and the smaller the number, the closer to the height from the irradiated surface. Here, the height refers to the distance between the rear surface of the lens, that is, the surface from which light is emitted and the irradiated surface.

As shown in FIGS. 1, 2 and 5, FIG.
In the configuration described above, the edges of the laser beam incident on the irradiation surface 604 almost overlap each other, and the spread of the laser beam on the irradiation surface can be suppressed.

The present invention is effective not only for plano-convex lenses but also for biconvex lenses, convex meniscus lenses, biconcave lenses, plano-concave lenses, and concave meniscus lenses. In each case, the individual beams need to be split and incident on the lenses.

The present invention is effective not only for an optical system using a lens but also for an optical system using a reflecting mirror such as a convex mirror or a concave mirror. In each case, the individual beams need to be split and incident on the lens.

The divided lens according to the present invention may be adjusted so as to reduce aberration not only in the vertical direction but also in the horizontal direction and the oblique direction.

The present invention is not applied only to the laser optical system. In an optical system in which white light is incident, chromatic aberration occurs due to wavelength dispersion of the refractive index of the lens, but it is possible to reduce geometrical spherical aberration. Regarding chromatic aberration, it is preferable to achromatic by combining concave and convex lenses having different refractive index dispersions.

The present invention provides not only spherical aberration but also coma,
Astigmatism can also be reduced. In this case, the arrangement of the divided individual lenses becomes asymmetric with respect to the optical axis.

[0054]

[Embodiment 1] This embodiment shows an example in which cylindrical lenses having different focal lengths are divided and combined to reduce the spherical aberration of a spherical lens. The optical system was based on that shown in FIG.

In this embodiment, as the laser irradiation device 300, an L3308, XeCl excimer laser device manufactured by Lambda Physics Co., Ltd. was used. The specifications of the laser irradiation device are as follows. Pulse laser, maximum oscillation frequency 300 Hz, pulse width, 35 ns, maximum energy 670 mJ / pulse, maximum energy, 200 W. The beam size is 12 × 35 mm square at the laser exit.

Since the size of the beam emitted from the laser irradiation device is 12 × 35 mm, it was necessary to design an optical system according to the size.

FIG. 3A is a schematic view of a lens acting in the longitudinal direction of the linear laser beam, and FIG. 3B is a schematic view of a lens acting in the short direction of the linear laser beam in the optical system used in this embodiment. FIG. There are divided cylindrical lenses 3061 and 3062 near the irradiated surface.

The role, arrangement, and size of each lens of the optical system shown in FIG. 3 will be described below. The following lenses are
All are plano-convex lenses and cylindrical lenses 30
Except for 5, all have a curved surface in the laser incident direction. The orientations of these lenses do not have to be as described above, but if the orientations of the lenses are arranged differently from this embodiment, the effects disclosed by the present invention can be obtained unless the distance between the lenses is changed. May not be possible. In addition, the curved surfaces of all lenses are spherical. Further, the definition of the size of the cylindrical lens is unified as shown in FIG. H). All lenses are cylindrical lenses and have a curvature in the width direction.

In the cylindrical array lens 301, four cylindrical lenses having a focal length of 300 mm are arranged in an array. The widths (L ₁ ) are each 3 mm.
The length (W ₁ ) of the cylindrical array lens is 50 m
m, and the thickness (H ₁ ) is 3 mm.

In the cylindrical array lens 302, seven cylindrical lenses having a focal length of 72 mm are arranged in an array. The width (L ₂ ) is 7 mm and the length (W ₂ ) is 50 mm. Lens thickness (H ₂ ) is 3m
m.

As the cylindrical array lens 303, four cylindrical lenses having a focal length of 450 mm are arranged in an array. The width (L ₃ ) is 3 mm, the length (W ₃ ) is 50 mm, and the thickness (H ₃ ) is 3 mm.

The cylindrical lens 304 has a focal length of 1680 mm, a width (L ₄ ) of 50 mm, and a length (W ₄ ) of 50 m.
m, thickness (H ₄ ) 5 mm. By providing a curved surface on the side opposite to the laser incident direction, light incident on the cylindrical lens 304 spreads in the longitudinal direction of the linear beam.

The cylindrical lens 305 has a focal length of 375 mm, a width (L ₅ ) of 50 mm, and a length (W ₅ ) of 50 m.
m, thickness (H ₅ ) 5 mm. This lens acts in the short direction of the linear beam. By providing a curved surface in the laser incident direction, the cylindrical lens 30
The light incident on 4 is focused on the focal point 307 and becomes a single linear shape.

As the distance further advances, the light condensed at the focal point 307 is split into individual linear beams and incident on the divided cylindrical lenses 3061 and 3062. Since the divided cylindrical lens is located at a position about 1000 mm away from the focal point of the cylindrical lens 305, the distance between individual laser beams is widened.

The divided cylindrical lens 306 is located at the center
Lens 3061 has a focal length of 185 mm and a width (L₆)
15mm, length (W₆) 160 mm, thickness (H₆) 20m
m. Lenses 3062 at both ends are focal lengths respectively
173mm, width 20mm (W ₇), Length 160mm
(L₇), Thickness (H₇) 20 mm. In addition,
Lens 3062, the curvature of each of the left and right lenses
The hearts agree. Lenses with different focal lengths are set at different heights.
The split laser beam was focused
Although it is irradiated linearly, its spread is suppressed. here
The height is defined as the rear surface of the lens, that is, the surface from which light exits,
It refers to the distance to the launch surface 108. Split cylindrical callen
Rear surface of the lens 3061 at the center of the lens 306 and a split cylinder
The distance from the rear surface of the lens 3062 at both ends of the
The separation is 23 mm. Height of split cylindrical lens
The focal length was optimized by calculation.

By the action of the divided cylindrical lens 306, a laser beam which is longer and thinner than the linear laser formed at the focal point 307 of the cylindrical lens 304 is formed.

The distance between the rear surfaces of the lenses at both ends of the divided cylindrical lens 306 and the irradiated surface 108 is 192.5
mm.

The distance between the cylindrical array lens 301 and the cylindrical array lens 302 is 317 mm.

The distance between the cylindrical array lens 302 and the cylindrical array lens 303 is 122 mm.

The distance between the cylindrical array lens 303 and the cylindrical lens 304 is 1 mm.

The distance between the cylindrical lens 304 and the cylindrical lens 305 is 81 mm.

The distance between the cylindrical lens 305 and the central lens 3061 of the divided cylindrical lens 306 is 1377 mm.

The distance between the lenses described above is the shortest distance between the rear surface of the lens disposed earlier in the optical path and the front surface of the lens disposed later in the optical path. If it is necessary to insert a mirror between lenses due to the arrangement of the optical system, the lens arrangement may be changed according to geometrical optics.

Since the above-mentioned distance changes depending on the precision of the optical system and the displacement of the arrangement, the actual optical adjustment is
It is preferable to arrange a CCD camera or the like on the irradiation surface 108 and observe the beam.

The linear laser beam processed by the above configuration has a very high uniformity on the surface to be irradiated. The size of the linear laser beam is 145 m in length
m, width 0.6 mm.

[Embodiment 2] In this embodiment, an example in which an amorphous silicon film formed on a glass substrate is crystallized by using the linear laser beam of Embodiment 1 will be described.

The substrate was a 5-inch square Corning 1
737 substrate is used. An SiO ₂ film is formed to a thickness of 200 nm on a substrate by a plasma CVD method. Thereafter, an amorphous silicon film is continuously formed to a thickness of 50 nm.

Thereafter, the substrate is heated to 500 degrees to reduce hydrogen in the amorphous silicon film. Thereby, the laser resistance of the film can be improved.

An apparatus for irradiating a substrate with a laser is as follows:
As shown in FIG. The laser light emitted from the laser irradiation device 300 first enters the optical system 401. Optical system 40
Reference numeral 1 includes lenses 301 to 305 shown in FIG. The light emitted from the optical system 401 is bent vertically downward by the mirror 402, and is irradiated on the substrate 403 via the divided cylindrical lens 306.

The stage 404 is disposed in parallel with the surface to be irradiated with the linear laser beam, and the substrate 403 is placed thereon.
Can be arranged. The linear laser beam is focused on the surface of the substrate 403 placed on the stage 404. The stage 404 is moved by a moving mechanism 405 in a direction perpendicular to the length direction of the linear laser beam.
Designed to work with While the stage is moving, there should be adequate friction between the substrate and the stage so that the substrate does not move on the stage.

By adjusting the output of the laser irradiation device 300, the energy density of the laser beam on the surface to be irradiated is controlled, and the optimum energy for crystallizing the amorphous silicon film is selected.

The optimum laser oscillation output of the laser irradiation device made of lambda used in this embodiment is 15 to 16 keV.
It is. However, if the amorphous silicon film is irradiated with a linear laser beam at the above output, the output may be too strong. In that case, for example, a neutral density filter is inserted between the laser irradiation device 101 and the optical system 401 to adjust the output to an appropriate value.

It is preferable that the neutral density filter be capable of continuously changing the neutral density. Specifically, a mechanism may be provided in which a plate whose transmittance changes depending on the incident angle is used, the plate is inserted into the laser beam path, and the angle of the plate is changed. The dimming rate may be determined by the practitioner.

In this embodiment, the energy density of the linear laser beam on the surface to be irradiated is 300 to 450 mJ / c.
m ² , for example, 400 mJ / cm ^2, and the moving speed of the stage was 1-4 mm / sec, for example, 1.8 mm / sec. The oscillation frequency of the laser was set to 30 Hz.
At this time, paying attention to one point on the surface of the amorphous silicon film,
The laser beam is irradiated 10 times. It is preferable to irradiate the amorphous silicon film with a multi-pulse laser as described above, since fluctuations in laser output are averaged.

[Embodiment 3] In the present invention, a semiconductor layer is irradiated with a linear laser beam by an optical system using a divided cylindrical lens to crystallize the active layer. A method for manufacturing an active matrix substrate using low-temperature polysilicon as an active layer using the linear laser beam optical system of the present invention will be described below with reference to FIGS. An optical system for forming a linear laser will be described with reference to FIGS.

First, as shown in FIG. 9A, oxidation is performed on a substrate 2001 made of glass such as barium borosilicate glass represented by Corning # 7059 glass or # 1737 glass or aluminoborosilicate glass. A base film 2002 including an insulating film such as a silicon film, a silicon nitride film, or a silicon oxynitride film is formed. For example, a plasma CVD method _{SiH 4, NH 3, N 2} O silicon oxynitride film 2002a made from 10 to 20
nm (preferably 50-100 nm), and then
_4. Silicon oxynitride film 2002b made of N ₂ O
Is laminated to a thickness of 50 to 20 nm (preferably 100 to 150 nm). Although the base film 2002 has a two-layer structure in this embodiment, the base film 2002 may be formed as a single-layer film of the insulating film or a laminate of two or more layers.

The island-shaped semiconductor layers 2003 to 2006 and 205
Reference numeral 7 denotes a semiconductor film having an amorphous structure formed of a crystalline semiconductor film manufactured by a laser crystallization method or a thermal crystallization method. The thickness of the island-shaped semiconductor layers 2003 to 2006 is 25
It is formed to a thickness of about 80 nm (preferably 30 to 60 nm). The material of the crystalline semiconductor film is not limited, but is preferably formed of silicon or a silicon germanium (SiGe) alloy.

Preparation of crystalline semiconductor film by laser crystallization
To do this, use a pulse oscillation type or continuous emission type excimer
Lasers such as gas lasers, YAG lasers, and Y
VO _FourA solid-state laser represented by a laser is used. This
When using these lasers, the laser oscillator
The emitted laser light is converted into a linear or rectangular
Or using a method of condensing into a rectangular shape and irradiating the semiconductor film
good. Crystallization conditions are chosen by the practitioner
However, when using an excimer laser, the pulse oscillation frequency
30Hz, laser energy density 100 ~ 40
0mJ / cm^Two(Typically 200-300mJ / cm^Two). Ma
When a YAG laser is used, the second harmonic
The pulse oscillation frequency used was 1 to 10 kHz,
Energy density 300 ~ 600mJ / cm^Two(Typically 35
0-500mJ / cm^Two). And width 100-1
Laser light condensed linearly at 000 μm is transmitted over the entire substrate
And the superposition rate of the linear laser light at this time
(Overlap ratio) is set to 80 to 98%.

In this embodiment, a linear laser is irradiated by the optical system shown in the first and second embodiments. The XeCl excimer laser was used for the laser irradiation conditions as in Example 1. Maximum oscillation frequency is 300Hz, pulse width is 35nsec, maximum energy is 670mJ / pulse, maximum energy is 200W
And

The laser is irradiated with the same lens arrangement as that shown in FIG. 3 of the first embodiment. As a result, the four beams split by the cylindrical array lens 301 enter the split cylindrical lens 306. When each split beam reaches the surface to be irradiated, the edge of each beam overlaps and the substrate is irradiated with laser light having a uniform energy distribution. With the lens arrangement disclosed in the first embodiment, a laser beam condensed linearly with a width of 600 μm in the short direction is generated. As shown in FIG. 4, the substrate 403 is scanned in the short direction of the linear laser, that is, in the direction of the arrow in FIG. 4, and crystallization is performed sequentially. When the crystallized substrate is visually observed, a favorable crystal state in which vertical stripes after laser irradiation are inconspicuous can be obtained.

The gate insulating film 2007 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by a plasma CVD method or a sputtering method. In this embodiment, 12
It is formed of a silicon oxynitride film with a thickness of 0 nm. Needless to say, the gate insulating film is not limited to such a silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure. For example, when a silicon oxide film is used, TEOS (Tetr
aethyl Orthosilicate) and O ₂ and a reaction pressure of 4
0 Pa, a substrate temperature of 300 to 400 ° C., and a high frequency (13.
56 MHz) It can be formed by discharging at a power density of 0.5 to 0.8 W / cm ² . The silicon oxide film thus manufactured can obtain good characteristics as a gate insulating film by subsequent thermal annealing at 400 to 500 ° C.

[0092] Then, a first conductive film 2008 and a second conductive film 2009 for forming a gate electrode are formed over the gate insulating film 2007. In this embodiment, the first conductive film 2008 is formed of Ta to a thickness of 50 to 100 nm, and the second conductive film is formed of W to a thickness of 100 to 300 nm.

The Ta film is formed by a sputtering method, and a Ta target is sputtered with Ar. In this case, when an appropriate amount of Xe or Kr is added to Ar, the internal stress of the Ta film can be relaxed and the film can be prevented from peeling. The resistivity of the α-phase Ta film is about 20 μΩcm and can be used for the gate electrode, but the resistivity of the β-phase Ta film is about 180 μΩcm and is not suitable for the gate electrode. α phase T
If a tantalum nitride having a crystal structure close to the α phase of Ta is formed on a base of Ta with a thickness of about 10 to 50 nm in order to form the a film, a Ta film of the α phase can be easily obtained. .

When a W film is formed, it is formed by a sputtering method using W as a target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to lower the resistance in order to use it as a gate electrode.
It is desirable to set the resistance to Ωcm or less. The resistivity of the W film can be reduced by enlarging the crystal grains. However, when there are many impurity elements such as oxygen in W, crystallization is inhibited and the resistance is increased. From this, when using the sputtering method,
By using a W target having a purity of 99.9999% and forming a W film with sufficient care so as not to mix impurities from the gas phase during film formation, the resistivity is 9 to 20 μΩc.
m can be realized.

Next, as shown in FIG. 9B, masks 2010 to 2013 made of resist are formed, and a first etching process for forming a gate electrode is performed. Although the etching method is not limited, preferably, the ICP (Inductively
Coupled Plasma: using inductively coupled plasma) etching method, a mixture of CF ₄ and Cl ₂ as etching gas, 0.
At a pressure of 5-2 Pa, preferably 1 Pa, 5
The plasma is generated by supplying 00 W RF (13.56 MHz) power. 100W R on substrate side (sample stage)
F (13.56 MHz) power is applied and a substantially negative self-bias voltage is applied. When CF ₄ and Cl ₂ are mixed, the W film and the Ta film are etched to the same extent.

Under the above-mentioned etching conditions, the shape of the resist mask is made appropriate, so that the end portions 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. Become. The angle of the tapered portion is 15 to 45 °. In order to perform etching without leaving a residue on the gate insulating film, the etching time may be increased by about 10 to 20%. Since the selectivity of the silicon oxynitride film to the W film is 2 to 4 (typically 3), the exposed surface of the silicon oxynitride film is etched by about 20 to 50 nm by the over-etching process. In this manner, the first shape conductive layers 2014 to 2017 (the first conductive layer 2001) including the first conductive layer and the second conductive layer are formed by the first etching process.
4a-20017a and second conductive layers 2014b-201
7b) is formed. Reference numeral 2054 denotes a gate insulating film, and a region which is not covered with the first shape conductive layers 2014 to 2017 is etched to a thickness of about 20 to 50 nm to form a thinned region.

Then, a first doping process is performed to add an impurity element imparting n-type. The doping may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose is 1 × 10 ^{13 to} 5 × 10
^{It is performed at 14} atoms / cm ² and an acceleration voltage of 60 to 100 keV. An element belonging to Group 15 of the periodic table, typically phosphorus (P) or arsenic (As) is used as the n-type impurity element. Here, phosphorus (P) is used. In this case, the conductive layer 2
Reference numerals 014 to 2017 serve as masks for the impurity element imparting n-type, and the first impurity region 2018 is self-aligned.
2021 and 2055 are formed. The first impurity regions 2018 to 20021 and 2055 have 1 × 10 ²⁰ to 1 ×
An impurity element for imparting n-type is added in a concentration range of 10 ²¹ atomic / cm ³ .

Next, a second etching process is performed as shown in FIG. Similarly, using an ICP etching method, CF ₄ , Cl _2, and O ₂ are mixed as an etching gas, and a 500 W RF power (13.56 MHz) is applied to the coil electrode at a pressure of 1 Pa.
Is supplied to generate plasma. An RF (13.56 MHz) power of 50 W is applied to the substrate side (sample stage), and a lower self-bias voltage is applied than in the first etching process. Under these conditions, the W film is anisotropically etched, and the first conductive layer Ta is anisotropically etched at a lower etching rate to form the second shape conductive layers 2022 to 2025 (first Conductive layers 2022a to 2022
5a and second conductive layers 2022b to 2025b). Reference numeral 2026 denotes a gate insulating film, and a region which is not covered with the second shape conductive layers 2022 to 2025 is 20 to 20
A thin region is formed by etching about 50 nm.

The etching reaction of the W film or the Ta film by the mixed gas of CF ₄ and Cl ₂ can be inferred from the generated radical or ion species and the vapor pressure of the reaction product.
Comparing the vapor pressures of fluorides and chlorides of W and Ta, W
WF ₆ is extremely high and other WC
l ₅ , TaF ₅ and TaCl ₅ are comparable. Therefore, C
With the mixed gas of F ₄ and Cl ₂ , both the W film and the Ta film are etched. However, when an appropriate amount of O ₂ is added to this mixed gas, CF ₄ and O ₂ react to form CO and F, and a large amount of F radicals or F ions are generated. As a result, the etching rate of the W film having a high fluoride vapor pressure increases. On the other hand, in Ta, the increase in the etching rate is relatively small even if F increases. Further, since Ta is more easily oxidized than W, the surface of Ta is oxidized by adding O ₂ .
Since the oxide of Ta does not react with fluorine or chlorine,
The etching rate of the a film decreases. Therefore, the W film and Ta
It is possible to make a difference in the etching rate with the film, and it is possible to make the etching rate of the W film larger than that of the Ta film.

Then, a second doping process is performed as shown in FIG. In this case, an impurity element imparting n-type is doped under a condition of a high acceleration voltage with a lower dose than in the first doping process. For example, the acceleration voltage is set to 70 to 120 keV and the dose is set to 1 × 10 ¹³ / cm ² , and a new impurity region is formed inside the first impurity region formed in the island-shaped semiconductor layer in FIG. Form. The doping is performed using the second shape conductive layers 2022 to 2025 as a mask for an impurity element.
Doping is performed so that an impurity element is also added to a region below a to 2025a. Thus, the second conductive layer 20
Third impurity region 2032 overlapping with 22a to 2025a
To 2036 and second impurity regions 2027 to 2031 between the first impurity region and the third impurity region. The impurity element imparting n-type is set to have a concentration of 1 × 10 ¹⁷ to 1 × 10 ¹⁹ atoms / cm ³ in the second impurity region and 1 × 10 ¹⁶ to 1 × 10 ^{18 in} the third impurity region. atoms /
The concentration should be cm ³ .

Then, as shown in FIG. 10B, the fourth impurity regions 2037 to 203 of the conductivity type opposite to the one conductivity type are formed in the island-shaped semiconductor layer 2004 forming the p-channel TFT.
9 is formed. Using the second conductive layer 2023 as a mask for the impurity element, an impurity region is formed in a self-aligned manner. At this time, the entire surface of the island-shaped semiconductor layers 2003, 2005, and 2006 forming the n-channel TFT is covered with resist masks 2040 to 2042. Each of the impurity regions 2037 to 2039 is doped with phosphorus at a different concentration, but is formed by an ion doping method using diborane (B ₂ H ₆ ), and the impurity concentration in each of the regions is 2 × 10 ²⁰ to ²⁰ × 10 ²⁰ . It is set to 2 × 10 ²¹ atoms / cm ³ .

Through the above steps, impurity regions are formed in each of the island-shaped semiconductor layers. First conductive layer 2022-2
025 functions as a gate electrode and a gate wiring.

In order to control the conductivity type in this way, FIG.
As shown in (C), a step of activating the impurity element added to each of the island-shaped semiconductor layers is performed. This step is
Laser annealing can be applied.

In the laser annealing method, an excimer laser beam having a wavelength of 400 nm or less, the second harmonic (532 nm) of a YAG laser or a YVO ₄ laser is used. Activation conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 Hz, and the laser energy density is 100 to 300 mJ / cm ² . When a YAG laser is used, the second harmonic is preferably used to set the pulse oscillation frequency to 1 to 10 kHz and the laser energy density to 200 to 400 mJ / cm ² . Then, a laser beam condensed linearly with a width of 100 to 1000 μm, for example, 600 μm, is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is set to 80 to 98%.

When the optical system shown in FIG. 3 is used to form a linear laser, the laser beam split by the cylindrical lens 301 is condensed on the substrate. Energy distribution can be made uniform. In this embodiment, a linear laser is irradiated with the lens arrangement of the optical system shown in the first and second embodiments. The XeCl excimer laser was used for the laser irradiation conditions as in Example 1.

As a result, the four beams split by the cylindrical array lens 301 shown in FIG. 3 enter the split cylindrical lens 306. With the lens arrangement disclosed in the first embodiment, a laser beam condensed linearly with a width of 600 μm in the short direction is generated. As shown in FIG.
3 is scanned in the short direction of the linear laser, that is, in the direction of the arrow in FIG. 4, and activation is sequentially performed. Since the laser energy distribution is uniform, impurities can be activated uniformly.

Further, a heat treatment is performed at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% of hydrogen to hydrogenate the island-like semiconductor layer. In this step, dangling bonds in the semiconductor layer are terminated by thermally excited hydrogen. As another means of hydrogenation,
Plasma hydrogenation (using hydrogen excited by plasma) may be performed.

Further, a capacitance electrode 2053 is formed. The capacitor electrode 2053 may be manufactured in the step of FIG. Then, the gate electrode and the capacitor electrode can be manufactured with one mask. Thereby, a storage capacitor is formed between the capacitor electrode and the n-type doped active layer 2055.

In FIG. 11, first interlayer insulating film 204
3 is formed from a silicon oxynitride film with a thickness of 100 to 200 nm. A second interlayer insulating film 2044 made of an organic insulating material is formed thereon. Second interlayer insulating film 2043
Is formed with an average film thickness of 1.0 to 2.0 μm. Organic insulator materials include polyimide, acrylic, polyamide,
Polyimide amide, BCB (benzocyclobutene) and the like can be used. For example, in the case of using a polyimide of a type that is thermally polymerized after being applied to a substrate, it is formed by firing at 300 ° C. in a clean oven. In the case of using acrylic, after using a two-pack type, mixing the main material and the curing agent, applying the entire surface of the substrate using a spinner, and preheating at 80 ° C. for 60 seconds on a hot plate. Then, it can be formed by firing in a clean oven at 250 ° C. for 60 minutes.

Then, a source wiring 2045 for forming a contact with the source region of the island-shaped semiconductor layer in the driver circuit.
2047 to 2047, and drain wirings 2048 to 2050 forming a contact with the drain region are formed.

In the pixel portion, the source wiring 20
51, forming a pixel electrode 2052; The wiring formed on the second interlayer insulating film 552 is, for example, 50 to 20
It is formed of a 0 nm Ti film and a 100 to 300 nm Al film.
Source wirings 2045 to 20 formed in such a configuration
47 and 2048, the drain wirings 2048 to 2050, and the pixel electrode 2052 make contact with the source or drain region of the TFT with the Ti film through the contact hole formed in the second interlayer insulating film, and the semiconductor is made of aluminum and Al. It prevents direct contact and reaction, and enhances the reliability of the contact part.

As described above, the n-channel TFT 30
01, p-channel TFT 30002, n-channel TFT
A driving circuit having an FT3003 and a pixel TFT 3000
4. A pixel portion having the storage capacitor 30005 can be formed over the same substrate. In this specification, such a substrate is referred to as an active matrix substrate for convenience.

AA ′ in FIG. 12 of the top view of the pixel portion of the active matrix substrate manufactured in this embodiment corresponds to the line AA ′ in FIG. In the pixel TFT 3004, the gate electrode 2025 also serving as a gate wiring crosses the island-like semiconductor layer 2008 thereunder via a gate insulating film (not shown). Although not shown, a source region, a drain region, and an LDD region are formed in the island-shaped semiconductor layer. 5001 is a source wiring 2051
Contact portion between the pixel electrode 2 and the source region 5002
This is a contact portion between the area 052 and the drain region. The storage capacitor 5003 is connected to the semiconductor wiring extending from the drain region of the pixel TFT 3004 and the capacitor wiring 20 via a gate insulating film.
53 are formed in overlapping regions.

In this embodiment, since the crystallization can be made uniform by the linear laser, the variation in the characteristics of the switching elements in the substrate surface due to uneven laser irradiation can be suppressed. Also, as in the present embodiment, the optical system in which the cylindrical lens is divided and the aberration of the lens is reduced is used not only for crystallization of the semiconductor layer but also for activating impurity ions doped in the semiconductor layer by a laser annealing method. Can also be used.

[Embodiment 4] In this embodiment, the configuration of a reflection type liquid crystal display device using the active matrix substrate manufactured in Embodiment 3 will be described with reference to FIG.

The method for manufacturing the counter substrate will be described below. The substrate 40001 may be Corning # 7059 glass or #
In addition to glass substrates such as barium borosilicate glass and aluminoborosilicate glass represented by 1737 glass, etc., optical anisotropy such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyether sulfone (PES) Can be used. It is desirable to use a substrate having the same thermal expansion coefficient as that of the substrate 2001 in order to prevent the substrate from being distorted in a later-described hot pressing step.

The color filter layer 40 is formed on the substrate 40001.
002 is formed. The color filter layer is also formed below a sealing material 40003, which will be described later, and is adjusted so that a gap is uniform between the display region and the sealing material forming region.

An overcoat material 40004 is formed on the color filter layer 40002. The overcoat material has a function of flattening the overlap of the red, blue and green color filters of each color. In a reflective panel, the panel is displayed using external light. No light-blocking film is provided in order to minimize the loss of brightness.

On the overcoat material 40004, an indium tin oxide (ITO) film is formed as a transparent conductive film 40005. Indium tin oxide (I
If there is a (TO) film, an unnecessary capacitance is formed in the drive circuit, and the waveform becomes blunt. Therefore, the indium tin oxide (ITO) film in the drive circuit area is removed by patterning. Thus, a counter substrate is manufactured.

The film forming spacer 40006 is formed on the source wiring 2051 by using NN700 manufactured by JSR Corporation.
In this embodiment, a film forming spacer is formed on a counter substrate.

The orientation film 40008 has a substrate 4000 of 60 nm.
1, 2001. The alignment film includes a soluble polyimide and a thermosetting polyamic acid.

As the sealing material 40003, a thermosetting epoxy resin or an ultraviolet curing epoxy resin can be used.
A liquid crystal material 40009 is sandwiched between the substrates. The liquid crystal material is appropriately selected according to the alignment mode.

[Embodiment 5] The active matrix substrate manufactured in Embodiment 3 can be applied to a reflection type liquid crystal display device as it is. On the other hand, in the case of a transmissive liquid crystal display device, a pixel electrode provided for each pixel in the pixel portion may be formed of a transparent electrode. In this embodiment, a method for manufacturing an active matrix substrate corresponding to a transmission type liquid crystal display device will be described with reference to FIGS.

The active matrix substrate is manufactured in the same manner as in the third embodiment. In FIG. 14A, a source wiring 2051
The drain wiring 2052 is formed by forming a conductive metal film by a sputtering method or a vacuum evaporation method. This is because the Ti film is
Forming a contact with a semiconductor film forming a source or drain region of an island-shaped semiconductor layer;
Aluminum (Al) is superposed on the Ti film for 300 to
It was formed to a thickness of 400 nm, and a Ti film or a titanium nitride (TiN) film was formed to a thickness of 100 to 200 nm to form a three-layer structure. After that, a transparent conductive film is formed over the entire surface, and a pixel electrode 2056 is formed by patterning and etching using a photomask. The pixel electrode is formed over the interlayer insulating film, and has a portion overlapping with the drain wiring 2052 of the pixel TFT to form a connection structure.

In FIG. 14B, first, a transparent conductive film is formed on the interlayer insulating film, and patterning and etching are performed to form a pixel electrode.
2 is an example in which a portion overlapping with the pixel electrode 2056 is provided. The drain wiring 2052 is formed of a Ti film of 50 to 150
A contact is formed with the semiconductor film forming the source or drain region of the island-shaped semiconductor layer, and aluminum (Al) is formed on the Ti film so as to have a thickness of 300 to 4 nm.
It is formed and provided with a thickness of 00 nm. With this configuration,
The pixel electrode 2056 is formed of a T
It comes into contact with only the i film. As a result, it is possible to prevent the reaction between the transparent conductive film material and Al. Source wiring 2
051 is formed simultaneously with the drain wiring 2052.

The material of the transparent conductive film is indium oxide (I
n ₂ O ₃ ), an indium tin oxide (ITO) film, or the like can be formed using a sputtering method, a vacuum evaporation method, or the like. The etching of such a material is performed using a hydrochloric acid-based solution. However, in particular, since etching of ITO easily generates residues, an indium oxide-zinc oxide alloy (In ₂ O ₃ —ZnO) may be used in order to improve the etching processability. Since indium oxide zinc oxide alloy has excellent surface smoothness and thermal stability to ITO,
Corrosion reaction with Al contacting at the end surface of the drain wiring can be prevented. Similarly, zinc oxide (ZnO) is a suitable material, and zinc oxide (ZnO: Ga) to which gallium (Ga) is added in order to increase the transmittance and conductivity of visible light can be used.

Thus, an active matrix substrate corresponding to a transmission type liquid crystal display device can be completed.

[Embodiment 6] An active matrix substrate, a liquid crystal display device, and an E manufactured according to the present invention are manufactured.
The L-type display device can be used for various electro-optical devices. The present invention can be applied to all electronic devices incorporating such an electro-optical device as a display medium. Examples of the electronic device include a personal computer, a digital camera, a video camera, a portable information terminal (such as a mobile computer, a mobile phone, and an electronic book), and a navigation system. Examples of these are shown below.

FIG. 15A shows a mobile phone, and a main body 90.
01, audio output unit 9002, audio input unit 9003, display device 9004, operation switch 9005, antenna 900
6. The present invention is an audio output unit 900
2. The present invention can be applied to a display device 9004 including an audio input unit 9003 and an active matrix substrate.

FIG. 15B shows a video camera, which includes a main body 9101, a display device 9102, an audio input portion 9103, operation switches 9104, a battery 9105, and an image receiving portion 91.
06. The present invention provides a voice input unit 9103,
910 provided with active matrix substrate
2. It can be applied to the image receiving unit 9106.

FIG. 15C shows a mobile computer or a portable information terminal.
02, an image receiving section 9203, operation switches 9204, and a display device 9205. The present invention relates to an image receiving unit 920.
3 and display device 9 including active matrix substrate
205 can be applied.

FIG. 15D shows a head-mounted display, which comprises a main body 9301, a display device 9302, and an arm portion 9303. The present invention can be applied to the display device 9302. Although not shown, it can be used for other signal control circuits.

FIG. 15E shows a television, which is a main body 940.
1, a speaker 9402, a display device 9403, a receiving device 9404, an amplifying device 9405, and the like. Example 5
The liquid crystal display device shown by, and the EL display device shown by Embodiment 6 or 7 can be applied to the display device 9403.

FIG. 15F shows a portable book, and a main body 95.
01, display devices 9502 and 9503, storage medium 950
4, comprising an operation switch 9505 and an antenna 9506 for displaying data stored on a mini disk (MD) or a DVD or data received by the antenna. The display devices 9502 and 9503 are direct-view display devices, and the present invention can be applied to this.

FIG. 16A shows a personal computer, which includes a main body 9601, an image input section 9602, and a display device 9.
603 and a keyboard 9604.

FIG. 16B shows a player that uses a recording medium (hereinafter, referred to as a recording medium) on which a program is recorded, and includes a main body 9701, a display device 9702, and a speaker unit 97.
03, a recording medium 9704, and operation switches 9705. This device uses a DVD (Di) as a recording medium.
It is possible to watch music, watch a movie, play a game, or use the Internet by using a CD (g. Versatile Disc) or a CD.

FIG. 16C shows a digital camera, which comprises a main body 9801, a display device 9802, an eyepiece 9803, operation switches 9804, and an image receiving unit (not shown).

FIG. 17A shows a front type projector, which comprises a display device 9901 and a screen 9902. The present invention can be applied to a display device and other signal control circuits.

FIG. 17B shows a rear type projector, which is composed of a main body 10001, a projection device 10002, and a mirror 10.
003 and a screen 10004. The present invention can be applied to a display device and other signal control circuits.

Note that FIG. 17C shows the projection devices 9901 and 10002 in FIGS. 17A and 17B.
FIG. 3 is a diagram showing an example of the structure of FIG. Projection device 9901, 1
0002 denotes a light source optical system 10101 and a mirror 1010
2, 10104 to 10106, dichroic mirror 1
0103, prism 10107, liquid crystal display device 1010
8, a phase difference plate 10109 and a projection optical system 10110. The projection optical system 10110 is configured by an optical system including a projection lens. This embodiment shows an example of a three-plate type,
There is no particular limitation, and for example, a single plate type may be used. Also,
The practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, and an IR film in the optical path indicated by the arrow in FIG.

FIG. 17D is a diagram showing an example of the structure of the light source optical system 10201 in FIG. 17C. In the present embodiment, the light source optical system 10201 includes a reflector 10211, a light source 10212, and a lens array 1012.
213, 10214, a polarization conversion element 10215, and a condenser lens 10216. Note that the light source optical system shown in FIG. 17D is an example and is not particularly limited. For example, a practitioner may appropriately provide an optical lens, a film having a polarizing function, a film for adjusting a phase difference,
An optical system such as an R film may be provided.

[0142]

The laser irradiation apparatus uses a quartz lens to suppress the absorption of short-wavelength light, but it is difficult to process the quartz lens with an aspherical surface. However, the present invention can reduce the aberration of the spherical lens.

Since the individual beams passing through each of the divided condensing lenses, which is a feature of the present invention, can be moved independently on the surface to be irradiated, more precise optical adjustment becomes possible.

When the present invention is applied to a laser irradiation apparatus, it is possible to obtain a linear laser beam having more homogeneity than using an expensive and difficult optical system such as a doublet cylindrical lens. it can.

[0145]

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention (a cylindrical lens is divided).

FIG. 2 shows an embodiment of the present invention (divided into cylindrical lenses having different focal lengths).

FIG. 3 shows an optical system according to a first embodiment.

FIG. 4 shows an optical system according to a second embodiment.

FIG. 5 shows an example in which lens aberration is reduced according to the present invention.

FIG. 6 shows an example in which light is condensed in a point shape according to the present invention.

FIG. 7 shows an optical system for forming a split beam.

FIG. 8 shows an energy profile by a laser irradiation device.

FIG. 9 is a cross-sectional view of a manufacturing process of a pixel TFT and a TFT of a driver circuit.

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

FIG. 11 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit.

FIG. 12 shows a top view of a pixel TFT.

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

FIG. 14 shows a pixel TF applied to a transmissive liquid crystal display device.
T is a cross-sectional view of a manufacturing step of a TFT of a driver circuit.

FIG. 15 illustrates an example of a semiconductor device.

FIG. 16 illustrates an example of a semiconductor device.

FIG. 17 shows a configuration of a projection type liquid crystal display device.

FIG. 18 shows a conventional laser irradiation apparatus.

FIG. 19 shows a conventional laser irradiation apparatus.

FIG. 20 shows a conventional laser irradiation apparatus.

FIG. 21 shows aberrations of a conventional lens.

FIG. 22 shows a configuration of a cylindrical lens.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/268 G02F 1/136 500 29/786 H01L 29/78 627G 21/336 F-term (Reference) 2H092 HA04 HA05 JA24 JA28 JA41 JA44 JB05 JB07 KA04 KA07 KB25 MA04 MA05 MA30 MA35 NA25 NA27 PA02 PA03 PA04 5F052 AA02 BA07 BA18 BB02 BB07 CA07 DA02 DB03 DB07 5F110 AA30 BB02 CC02 DD01 DD02 DD13 DD14 DD15 DD17 EE01 EE04 FF01 EE11 EE04 EE01 EE04 EE01 EE04 EE01 EE04 EE04 FF36 GG01 GG02 GG13 GG25 GG45 HJ01 HJ04 HJ07 HJ13 HJ18 HJ23 HL01 HL03 HL04 HL11 HL23 HM15 NN03 NN04 NN22 NN27 NN36 NN72 NN73 PP03 PP05 PP06 PP35 QQ04 QQ11 QQ24 QQ25

Claims (22)

[Claims] 1. A laser irradiation apparatus characterized in that aberrations on a surface to be irradiated are reduced by dividing a spherical lens into a plurality of parts and making the spherical surface discontinuous. 2. A single spherical lens is divided into a plurality of spherical lenses, a beam divided corresponding to each of the plurality of divided spherical lenses is incident, and the one spherical lens is divided into a plurality of spherical lenses. A laser irradiation apparatus characterized in that the divided beam forms an image at one location on the surface to be irradiated by making the spherical surface discontinuous. 3. A spherical lens having a constant radius of curvature is divided into a plurality of divided spherical lenses, and beams divided corresponding to individual lenses of the plurality of divided spherical lenses are incident on the spherical lens. A laser irradiation apparatus characterized in that a spherical lens having a sphere is divided into a plurality of parts and the spherical surface is made discontinuous so that the divided beam forms an image on a surface to be irradiated at one place. 4. A spherical lens having a different focal length is divided into individual lenses, and the divided lenses are combined. A beam divided corresponding to each of the plurality of divided spherical lenses enters, and A laser characterized in that a spherical surface becomes discontinuous by combining individual lenses formed by dividing the spherical lenses having different focal lengths, and the divided beams form an image on a surface to be irradiated at one place. Irradiation device. 5. A laser irradiation apparatus according to claim 1, wherein said spherical lens is made of quartz. 6. A laser irradiation apparatus according to claim 1, wherein said spherical lens is a cylindrical lens. 7. A laser irradiation apparatus according to claim 6, wherein said cylindrical lens is divided by a plane parallel to a generating line. 8. A laser irradiation apparatus according to claim 7, wherein said cylindrical lens is divided by a plane parallel to an optical axis. 9. The laser irradiation apparatus according to claim 1, wherein the light refracted by each of the plurality of divided lenses is directly incident on a surface to be irradiated. 10. A laser irradiation apparatus according to claim 1, wherein the surface to be irradiated is irradiated with a linear laser beam. 11. A laser irradiation apparatus according to claim 1, wherein said spherical lens is divided by a plane parallel to an optical axis. 12. An optical system wherein a spherical lens is divided into a plurality of parts and a spherical surface is made discontinuous to reduce aberrations on an irradiated surface. 13. A spherical lens is divided into a plurality of spherical lenses, and a beam divided corresponding to each of the plurality of divided spherical lenses is incident, and the one spherical lens is divided into a plurality of spherical lenses. A laser irradiation apparatus characterized in that the divided beam forms an image at one location on the surface to be irradiated by making the spherical surface discontinuous. 14. A spherical lens having a constant radius of curvature is divided into a plurality of divided spherical lenses, and beams divided corresponding to individual lenses of the plurality of divided spherical lenses are incident on the spherical lens. A laser irradiation apparatus characterized in that a spherical lens having a sphere is divided into a plurality of parts and the spherical surface is made discontinuous so that the divided beam forms an image on a surface to be irradiated at one place. 15. A lens obtained by splitting spherical lenses having different focal lengths is combined, a beam split corresponding to each of the plurality of split spherical lenses is incident, A laser characterized in that a spherical surface becomes discontinuous by combining individual lenses formed by dividing spherical lenses having different focal lengths, and the divided beams form an image on a surface to be irradiated at one place. Irradiation device. 16. An optical system according to claim 12, wherein said spherical lens is made of quartz. 17. An optical system according to claim 12, wherein said spherical lens is a cylindrical lens. 18. An optical system according to claim 17, wherein said cylindrical lens is divided by a plane parallel to a generating line. 19. An optical system according to claim 18, wherein said cylindrical lens is divided by a plane parallel to an optical axis. 20. An optical system according to claim 12, wherein the light refracted by each of said divided lenses is directly incident on a surface to be irradiated. 21. An optical system according to claim 12, wherein the surface to be irradiated is irradiated with a linear laser beam. 22. An optical system according to claim 12, wherein said spherical lens is divided by a plane parallel to an optical axis.