JP2003100635A - Crystallizing device, crystallizing method, image display device and portable electronic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystallizing device capable of surely obtaining a crystal having a satisfactory size and capable of obtaining a satisfactory carrier mobil ity. SOLUTION: Laser beams irradiate a photomask and the passing beams of a first opening 112 of an opening 11 irradiate a thin film to crystallize the same. The irradiation area of the first opening 112 is moved into a short side direction to irradiate the laser beams and grow further the crystal formed previously. This operation is repeated to form a first crystallizing area. The passing beams of a second opening 113 irradiate the first crystallizing area to grow the crystal in the first crystallizing area into a direction orthogonal to the growing direction of the crystal in the first crystallizing area. The projecting area of the second opening 113 is moved into the short side direction to irradiate the laser beams and grow further the crystal in a direction orthogonal to the first crystallizing area. This operation is repeated to form a second crystallizing area extended from the inside of the first crystallizing area into a direction orthogonal to the direction of the first crystallizing area.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a crystallization device, a crystallization method, an image display device, and a portable electronic device.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used for displaying personal computers and home televisions. In this liquid crystal display device, liquid crystal is sealed between two glass substrates provided with electrodes, and electro-optical characteristics of the liquid crystal are changed by a voltage applied to the electrodes to display an image. In order for the liquid crystal display device to display an image, a plurality of pixel electrodes corresponding to a plurality of pixels forming a screen are
A predetermined voltage is applied to each to change the electro-optical characteristics of the liquid crystal for each pixel. At this time, as a method for applying a voltage to the pixel, there is a method in which a thin film transistor is provided for each pixel and the voltage applied to the pixel is controlled by this transistor. This system is called a TFT (Thin Film Transistor) active matrix system and is capable of displaying high-quality images, and is therefore widely used for the display of the computer and the display of the home television.

Separately from the above liquid crystal display device, a thin film having an electroluminescence effect is formed on a substrate, and a voltage is applied to the thin film to emit light, so-called EL.
(Electroluminescence) panels have also been put to practical use. There are two types of EL panels, one using an organic material and the other using an inorganic material for the thin film.
A screen is composed of a plurality of pixels, and a voltage is individually applied to the plurality of pixels to display an image.

In both the liquid crystal display device and the EL panel, it is necessary to form a transistor connected to a pixel electrode on a substrate forming a screen, and a thin film transistor is often used as the transistor. When a signal voltage for displaying an image is sequentially applied to a plurality of pixels, the thin film transistor turns on the pixel to which the signal should be applied. When no signal is applied to the pixel, the transistor is off, which holds the voltage of the pixel electrode until the next signal is applied, thereby maintaining the brightness of the pixel.

In the above liquid crystal display device and EL panel, an amorphous silicon film is formed on a glass substrate or a plastic substrate, and a thin film transistor is formed on this amorphous silicon film.

However, since the thin film transistor formed on the amorphous silicon film has a low carrier mobility and a relatively slow response, an image display device using the amorphous silicon film causes an afterimage or a contrast when a moving image is displayed. There was a defect such as the decrease.

Further, in the above liquid crystal display device, a driver circuit for driving a pixel is formed on a silicon wafer, a circuit chip is cut out from this silicon wafer, adhered to a liquid crystal panel, and connected to the pixel. This is because the driver circuit is required to have high speed and low impedance, and it is difficult to obtain the required performance with the circuit formed on the amorphous silicon film.

Therefore, it has been considered to form a film capable of forming a transistor capable of high speed operation on a glass substrate or a plastic substrate, and form a pixel driving transistor and a driver circuit on this film.

As a method for forming the above film, an amorphous silicon film formed on a substrate is annealed by irradiation with a laser beam or the like to crystallize the amorphous and improve the performance such as electron mobility of the silicon film. There is something to do. As such an amorphous crystallization method, an excimer laser is used as a light source to form linear irradiation light (width several hundred μm, length several ten to several hundred mm),
There is a method in which the irradiation light is scanned in a direction perpendicular to the longitudinal direction to sequentially anneal the amorphous silicon film. In this crystallization method, silicon is recrystallized when an amorphous film having a width of several hundred μm is melted and solidified, and at this time, crystal grains having a diameter of 1 μm or less are obtained. In the transistor formed in this crystalline silicon film, carriers are scattered by grain boundaries of crystal grains, so that the carrier mobility is 1
There is a problem that it can be improved only to about 100 to ²⁰⁰ cm ² / V · s.

To solve this problem, special table 2000-
505241 comprises an excimer laser, a mask having a slit-shaped opening, an expander for changing the beam diameter of the laser, and a homogenizer system for uniformizing the energy distribution of the laser beam, An image from the opening of the mask irradiated by the excimer laser is imaged on the substrate by the lens to melt the film, and the above image is scanned by a small amount (about 0.5 μm), laser irradiation is performed each time, and the crystal is crystallized. A crystallization method of sequentially growing the is disclosed.

In this crystallization method, a narrow beam having a width of 5 to 10 μm, which is an image of the excimer laser beam from the opening of the mask, is irradiated onto the amorphous silicon film to melt the amorphous film, Crystallization occurs in the width direction of the beam. Then, the thin beam is moved in the direction perpendicular to the longitudinal direction to sequentially grow crystals in the width direction of the beam. In this crystallization method, when the molten region is solidified, a temperature distribution is generated in the width direction of the molten region, and this temperature distribution causes crystal growth in the width direction of the molten region. In this crystallization method, the width in which the above-mentioned crystal growth occurs is 1 μm or less. Therefore, once the silicon is melted and solidified, the beam is moved in the width direction by about 0.5 μm and connected to the crystal made before that. As described above, a new crystal is grown to generate a crystal long in the width direction of the beam. By repeating this, an elongated columnar crystal is obtained, and as a result, carrier scattering by the crystal grain boundaries is suppressed, and the carrier mobility in the transistor formed in this crystal film is increased.

[0012]

However, in the above crystallization method, the crystal grown in the width direction of the beam has a width of 0.5 μm to 1 μm, which is relatively small. There is a problem that it may not grow to a sufficient length.

In the elongated columnar crystal, grain boundaries are not always formed parallel to the growth direction. Therefore,
Even if the transistor channels are formed in the longitudinal direction of the crystal, the carriers still cross many grain boundaries, and as a result, the carriers are scattered at the grain boundaries, which makes it difficult to improve the mobility. .

Therefore, an object of the present invention is to provide a crystallization apparatus which can surely obtain a crystal of a good size and a good carrier mobility.

[0015]

In order to achieve the above object, the crystallization apparatus of the present invention comprises a photomask having a light transmission pattern and a light source for emitting light to the photomask. In a crystallization device for irradiating light passing through a transmission pattern from a light source onto a thin film on a substrate to crystallize the thin film, the light transmission pattern of the photomask has an elongated first opening and a first opening. And an elongated second opening extending in a direction substantially orthogonal to the direction in which the opening extends.

According to the above structure, the thin film on the substrate is irradiated with the passing light from the light source that has passed through the first opening of the light transmitting pattern of the photomask, and the portion of the thin film irradiated with the passing light is irradiated. Be crystallized. The irradiation area of the passing light of the first opening is moved in the lateral direction of the irradiation area, and the irradiation of the passing light of the first opening to the thin film is repeated, so that the irradiation area of the passing light is Crystals extending in the lateral direction are obtained. When the crystal grown by the light passing through the first opening is irradiated with the light passing through the second opening of the light transmission pattern of the photomask from the light source, the longitudinal direction of the first opening and the second opening Since the light passing through the second opening is substantially orthogonal to the longitudinal direction of the portion, the longitudinal direction of the irradiation region is substantially the same as the extending direction of the crystal. The irradiation area of the light passing through the second opening is moved in the lateral direction of the irradiation area, and the light passing through the second opening is irradiated to the thin film repeatedly to pass through the second opening. A crystal extending in a direction substantially the same as the longitudinal direction of the light irradiation region is grown in a direction substantially perpendicular to the direction in which the crystal extends. That is, the crystal grown to a relatively large length by the light passing through the first opening is further grown in a direction substantially perpendicular to the length direction while maintaining this length. Therefore, since the crystal is effectively formed to have a large size, the crystal growth may be interrupted during the crystal growth as in the conventional case,
It is difficult for crystal grain boundaries to be formed in different directions in the growth direction. As a result, a crystal region having a good size, a small number of crystal grain boundaries, and a grain boundary in substantially the same direction as the growth direction is formed in the thin film.

Here, the first opening and the second opening of the light transmission pattern of the photomask may be optical openings, and for example, the above may be formed on a substrate transparent to the light from the light source. Providing a light shield that blocks the light from the light source,
The opening may be formed by removing a part of the light shield to form a pattern through which light is transmitted.

The crystallization apparatus of one embodiment includes a plurality of the first openings of the photomask, and the plurality of first openings are arranged in parallel with each other at a predetermined interval, The second openings are arranged so as to be located on both sides of the plurality of first openings arranged in parallel.

According to the above-described embodiment, the thin film of the substrate is irradiated with the passing light from the light source that has passed through the plurality of first openings arranged in parallel with each other at the predetermined intervals, and further, the plurality of the plurality of first openings are provided. By moving the irradiation area of the passing light of the first opening in the lateral direction of the irradiation area and irradiating the passing light of the first opening to the thin film, the irradiation area of the passing light is shortened. A plurality of crystals extending in the hand direction are obtained.
When the plurality of crystals grown by the light passing through the first opening are irradiated with the light passing through the second opening,
The light passing through the opening has a longitudinal direction in the irradiation direction of the light that is substantially the same as the direction in which the crystal formed by the light passing through the first opening extends. By moving the irradiation area of the passing light of the second opening in the lateral direction of the irradiation area of the passing light and irradiating the passing light of the second opening to the thin film, the plurality of the plurality of thin films are repeated. The crystal holds the length of the irradiation area of the light passing through the second opening in the longitudinal direction,
The light is grown in the lateral direction of the irradiation area of the light passing through the second opening. As a result, since the plurality of crystals are effectively grown to a large size, the number of crystal grain boundaries is relatively small, and
A crystal region having a grain boundary in substantially the same direction as the growth direction is formed.

In the crystallization device of one embodiment, the irradiation area on the thin film of the first passing light that has passed through the first opening of the photomask is sequentially connected in the lateral direction of the irradiation area of the first passing light. As described above, the first moving means for moving the photomask or the substrate and the irradiation area on the thin film of the second passing light which has passed through the second opening of the photomask are the same as the irradiation area of the second passing light. Second moving means for moving the photomask or the substrate so as to be sequentially connected in the lateral direction, and light passing through from the light source when the movement of the photomask or the substrate by the first and second moving means is stopped. While irradiating the thin film, when the photomask or the substrate is moved by the first and second moving means, the light source and the first moving means are arranged so that the light passing through from the light source does not irradiate the thin film. And control means for controlling the serial second moving means.

According to the above embodiment, the photomask or the substrate is moved by the first moving means so that the irradiation area on the thin film by the first passing light is a short side of the irradiation area of the first passing light. Move in the direction. At this time, the thin film is not irradiated with the passing light by the control means. When the photomask or the substrate is moved to a predetermined position and this movement is stopped, the control means irradiates the thin film with passing light. Further, the photomask or the substrate is moved by the second moving means, and the irradiation area on the thin film by the second passing light moves in the lateral direction of the irradiation area of the second passing light. At this time, the thin film is not irradiated with the passing light by the control means. When the photomask or the substrate is moved to a predetermined position and this movement is stopped, the control means irradiates the thin film with passing light. Therefore, it is possible to reliably grow crystals in the irradiation regions of the first and second passing lights of the thin film, and to effectively perform crystal growth in the lateral direction of the irradiation regions of the first and second passing lights.

In the crystallization apparatus of one embodiment, the control means controls the first moving means and the light source to cause the thin film on the substrate to have a longitudinal length of the irradiation region of the first passing light. To form a first crystallization region having a width of, and extending in the lateral direction of the irradiation region of the first passing light, and controlling the second moving means and the light source to generate a first crystallization region in the first crystallization region. From the second extending in the lateral direction of the irradiation area of the second passing light from
Form a crystallized region.

According to the above embodiment, the photomask or the substrate is moved by the first moving means under the control of the control means, and the photomask or the substrate is stopped while the photomask or the substrate is stopped. The thin film is irradiated with the first passing light. By repeating this, the above thin film,
A first crystallization region extending in the lateral direction of the irradiation region of the first passing light is formed. With respect to the first crystallization region, the second moving means moves the photomask or the substrate, and the second passing light is emitted when the photomask or the substrate is stopped. By repeating this, a second crystallized region extending from the first crystallized region in the lateral direction of the irradiation region of the second passing light is formed. In the first crystallization region, a crystal having a relatively large length in the lateral direction of the first passing light is grown, and in the second crystallization region, the crystal is formed in a direction substantially perpendicular to the length direction of the crystal. As the crystals are grown, relatively large size crystals are effectively obtained.

In the crystallization apparatus of one embodiment, the first moving means moves sequentially in the thin film of the substrate such that the irradiation areas of the first passing light overlap in the lateral direction and move sequentially.
While moving the photomask or the substrate, the second moving means moves the photomask or the substrate so that the irradiation area of the second passing light overlaps in the lateral direction in the thin film of the substrate and moves sequentially. To move.

According to the above-described embodiment, the photomask or the substrate is moved by the first moving means, and the irradiation regions of the first passing light are sequentially moved so as to overlap in the lateral direction, and the first thin film is formed on the thin film. By irradiation with the passing light, the crystal of the thin film is effectively grown in the lateral direction of the irradiation region of the first passing light. Therefore, it is possible to effectively obtain a crystal which is continuous in the lateral direction of the irradiation region of the first passing light and has almost no interruption. Further, the photomask or the substrate is moved by the second moving means, and the irradiation areas of the second passing light are sequentially moved while being overlapped in the lateral direction,
By irradiating the thin film with the second passing light, the crystal of the thin film is effectively grown in the lateral direction of the irradiation region of the second passing light. Therefore, a crystal having almost no discontinuity in the lateral direction of the irradiation region of the second passing light can be effectively obtained.

In the crystallization device of one embodiment, the length of the first opening of the photomask in the longitudinal direction is not more than half the distance between the second openings.

According to the above embodiment, the crystal grown in the lateral direction of the irradiation area of the light passing through the first opening is further passed through the second opening by the light passing through the second opening. When the light is grown in the lateral direction of the irradiation region, the ineffective region is formed adjacent to the grown crystal by the light passing through the first opening. Here, since the length of the first opening in the longitudinal direction is equal to or less than half of the arrangement interval of the second opening, the ineffective region is effectively reduced.

An image display device according to one embodiment comprises a substrate obtained by crystallizing a thin film using the above-mentioned crystallization device.

The crystallization method of the present invention comprises the steps of irradiating a photomask having a light transmission pattern with light and irradiating the thin film on the substrate with the light passing through the light transmission pattern of the photomask. In the crystallization method, which comprises a step of moving the photomask or the substrate so that the light passing through the light-transmitting pattern of the photomask is irradiated to a position to be irradiated on the thin film on the substrate, The light transmission pattern includes an elongated first opening and the first opening.
And an elongated second opening extending in a direction substantially orthogonal to the direction in which the opening extends.

According to the above embodiment, the thin film on the substrate is irradiated with the passing light from the light source that has passed through the first opening of the light transmitting pattern of the photomask, and the thin film on the substrate is irradiated with the passing light. The part is crystallized. The light passing through the first opening is extended in the lateral direction of the irradiation area of the passing light by moving the irradiation area of the passing light in the lateral direction of the irradiation area and irradiating the thin film. Crystals are obtained. When the crystal grown by the light passing through the first opening is irradiated with the light passing through the second opening of the light transmission pattern of the photomask from the light source, the longitudinal direction of the first opening and the second opening Since the light passing through the second opening is substantially orthogonal to the longitudinal direction of the portion, the longitudinal direction of the irradiation region of the light is substantially the same as the extending direction of the crystal. Second above
The light passing through the opening is irradiated to the thin film by moving the irradiation area of the passing light in the lateral direction of the irradiation area, so that it is substantially the same as the longitudinal direction of the irradiation area of the passing light of the second opening. A crystal extending in the direction is grown in a direction substantially perpendicular to the direction in which the crystal extends. That is, a crystal grown to a relatively large length by the light passing through the first opening is grown in a direction substantially perpendicular to the length direction while maintaining this length. As a result, the crystal is effectively formed to have a large size, and thus it is difficult for the crystal growth to be interrupted during the growth of the crystal or for the crystal grain boundaries to be formed in different directions in the growth direction as in the conventional case. As a result, it is possible to surely obtain a crystal having a good size and a grain boundary in substantially the same direction as the growth direction.

Here, the first opening and the second opening included in the light transmission pattern of the photomask may be optical openings, and, for example, the first opening and the second opening may be formed on a substrate transparent to the light from the light source. Providing a light shield that blocks the light from the light source,
The opening may be formed by removing a part of the light shield to form a pattern through which light is transmitted.

In the crystallization method of one embodiment, the thin film on the substrate is formed by connecting the first passing light that has passed through the first opening to the irradiation region of the first passing light in the lateral direction of the irradiation region. And sequentially forming a first crystallization region having a width of the longitudinal length of the irradiation region of the first passing light and extending in the lateral direction of the irradiation region of the first passing light. The thin film on the substrate is sequentially irradiated with the second passing light that has passed through the second opening so that the irradiation region of the second passing light is continuous in the lateral direction of the irradiation region, and the first crystallization region. Forming a second crystallization region extending from the inside in the lateral direction of the irradiation region of the second passing light.

According to the above embodiment, the first passing light is sequentially applied to the thin film so that the irradiation area of the first passing light is continuous in the lateral direction of the irradiation area, and the thin film is irradiated with the first light. The first extending in the lateral direction of the irradiation region of the first passing light
A crystallized region is formed. The first crystallization region is sequentially irradiated with the second passing light so that the irradiation region of the second passing light is continuous in the lateral direction of the irradiation region, and
A second crystallization region extending from the crystallization region in the lateral direction of the irradiation region of the second passing light is formed. In the first crystallization region, a crystal having a relatively large length is grown in the lateral direction of the irradiation region of the first passing light, and in the second crystallization region, in a direction substantially perpendicular to the length direction. As the crystals are grown, relatively large size crystals are effectively obtained.

In the crystallization method of one embodiment, when forming the first crystallized region, the thin film on the substrate is provided with the first transmitted light in the lateral direction of the irradiation region of the first transmitted light. Make sure that the irradiation areas are partially overlapped and continuous.
When the second crystallized region is formed while the first pass light is sequentially irradiated, the second pass light irradiation region is formed in the lateral direction of the second pass light irradiation region in the thin film on the substrate. The second passing light is sequentially irradiated so as to be partially overlapped and continuous.

According to the above-described embodiment, when the first crystallization region is formed, in the thin film of the substrate, the irradiation region of the first passing light is overlapped in the lateral direction of the irradiation region so as to be continuous. The passing light is sequentially irradiated, and a crystal having almost no discontinuity in the lateral direction of the irradiation area of the first passing light is effectively formed. Further, when the second crystallization region is formed, the second passing light is sequentially irradiated so that the irradiation region of the second passing light overlaps and is continuous in the lateral direction of the irradiation region in the thin film of the substrate, Crystals having almost no discontinuity are effectively formed in the lateral direction of the irradiation region of the second passing light.

An image display device according to one embodiment includes a substrate obtained by crystallizing a thin film by the above crystallization method.

In the image display device of one embodiment, a transistor is formed in the crystallized region of the thin film.

According to the above-described embodiment, the transistor formed in the crystallized region of the thin film has a higher carrier mobility than the transistor formed in the region other than the crystallized region of the thin film, which enables high speed operation. Become.

In the image display device of one embodiment, the transistor drives the pixel electrode.

According to the above embodiment, since the pixel electrode is driven by the transistor capable of high speed operation in the image display device, high speed display is possible, and there is almost no afterimage, and good contrast is obtained. To be

In the image display device of one embodiment, the crystallized thin film includes a plurality of crystallized regions having substantially the same size, and the transistor is formed in each of the crystallized regions. There is.

According to the above embodiment, the transistor is formed in each of the plurality of crystallized regions having substantially the same size, and the crystallized region has substantially no grain boundary. The operation becomes faster.

In the image display device of one embodiment, a display circuit having a transistor formed on the crystallized region of the thin film is arranged around the image display region for displaying an image.

According to the above embodiment, the display circuit is arranged around the image display area, and the transistor included in the display circuit is formed in the crystallized area of the thin film and can operate at high speed. The display circuit has a sufficient operation speed required for image display. As a result, the image display area and the display circuit are integrally formed on the substrate,
An image display device having a small number of parts, a small size, low cost, and good reliability can be obtained.

In the image display device of one embodiment, the display circuit is composed of a plurality of blocks, and the plurality of blocks are formed in the crystallization region.

According to the above embodiment, the plurality of blocks forming the display circuit are formed in the plurality of crystallized regions, and the crystallized regions have substantially no grain boundaries. Therefore, the operation of the block is stably increased and the display circuit having a sufficient operation speed is formed.

In the image display device of one embodiment, the crystallized region has a rectangular shape, and the length of at least one side of the rectangular shape is the distance between the first openings or the distance between the second openings. Is approximately equal to any one of the intervals.

According to the above embodiment, in the image display device, the crystallization region provided in the image display device is formed by the crystallization device and the crystallization method to form a rectangle. In this crystallization region, the light passing through the first opening is kept until the region illuminated by the light passing through the first opening of the photomask in the crystallization region comes into contact with the region illuminated by the light passing through the adjacent first opening. It is irradiated sequentially and one side is the first
It has a length approximately equal to the distance between the openings. Further, the crystallized region is successively irradiated with the light passing through the second opening until the region irradiated with the light passing through the second opening comes into contact with the region irradiated with the light passing through the adjacent second opening. The other side has a length substantially equal to the distance between the second openings.

A portable electronic device according to one embodiment includes the above image display device.

According to the above embodiment, the portable electronic device includes the image display device, and the image display device includes the transistor formed in the crystallized thin film and the display circuit using the transistor. Since it is small, can display at high speed, has almost no afterimage, and has good contrast, it is possible to obtain, for example, a full-color display of a moving image and a small portable electronic device.

[0051]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a diagram showing a crystallization apparatus according to an embodiment of the present invention. This crystallization device has an excimer laser light source 1 as a light source, and a beam expander 2 for expanding the lateral direction of a beam cross section of about 15 × 30 mm emitted by the excimer laser light source 1. The light source may be an argon laser or a YAG laser.

The beam expander 2 has a cylindrical concave lens 3 for spreading the light emitted from the light source, and the cylindrical concave lens 3.
It is composed of a cylindrical convex lens 4 for converting the light spread by to parallel light. The beam expander may be configured by combining a plurality of concave lenses, a plurality of convex lenses, and a cylindrical lens.

On the output side of the beam expander 2,
A homogenizer 6 for uniformizing the light intensity distribution is provided, and the homogenizer 6 is composed of a microlens array 7 and a relay lens 8. After the light is divided into a plurality of parts by the microlens array 7, the light is recombined by the relay lens 8 to obtain light having a substantially uniform intensity distribution.

A photomask 10 is arranged on the exit side of the homogenizer 6, and the photomask 10 is provided with a light transmission pattern including an opening 11 which will be described later. The photomask 10 is connected to a drive mechanism 13 that drives the photomask 10 in the plane direction. The drive mechanism 13 includes an air bearing and a roller guide, and can drive the photomask 10 with an accuracy of 1 μm or less.

An objective lens 15 is arranged on the emission side of the photomask 10, and an image formed on the opening 11 by being irradiated on the photomask 10 is arranged on the emission side of the objective lens 15. An image is formed on the substrate 17.

FIG. 2 is a view showing a light transmission pattern which is provided on the photomask 10 and is formed of the opening 11. The openings 11 are a plurality of elongated first openings 11
2, 112 ... and a plurality of elongated second openings 113,
113 ... And. The longitudinal direction of the first opening 112 and the longitudinal direction of the second opening 113 are substantially perpendicular to each other. The first openings 112 are arranged parallel to each other with the longitudinal direction thereof oriented in the left-right direction in FIG.
The second opening 113 may include the plurality of first openings 112.
2 are arranged so as to be located on both sides in FIG.
The second openings 113 are also arranged in parallel with each other.

This crystallization apparatus is provided with the photomask 10 described above.
Of the crystallization method is stored in a control system configured by a computer or a sequencer, and the control system executes the program to control the crystallization apparatus, thereby performing a crystallization method. Ready to run.

Using the crystallization apparatus having the above structure, the substrate 17
Amorphous silicon film 1 as a thin film formed on top
Crystallize 8. This amorphous silicon film 18 is
A film having a thickness of approximately 10 to 100 nm is suitable, and the amorphous silicon film 18 having a thickness of 50 nm is used in this embodiment. This amorphous silicon film 18
Is formed by plasma CVD on a glass substrate. The amorphous silicon film may be formed on the glass substrate by sputtering or vapor deposition.

Here, for simplification, the opening 1 of FIG.
1 of the first openings 112, 112 shown in FIG.
... and a state in which the amorphous silicon film is crystallized by passing light passing through one second opening 113 will be described.

First, as shown in FIG. 1, an aperture image of the photomask 10 is formed on the substrate 17 on which the amorphous silicon film 18 is formed. This aperture image, that is, the irradiation region of the passing light that has passed through the opening 11 of the photomask has substantially the same size as the opening 11 of the photomask. The excimer laser light source 1 that irradiates the irradiation area with laser light preferably oscillates with a pulse width of about 20 to 100 ns and an optical power of about 200 to 1000 mJ / cm ² . The amorphous silicon film 18 irradiated with the laser light absorbs the energy of the laser light and is instantaneously melted, and is rapidly cooled after the irradiation of the laser light is finished. This cooling progresses from the edge of the irradiation area of the passing light toward the center.

FIG. 4 is a schematic diagram showing a columnar crystal 21 formed on the amorphous silicon film 18 from the edge of the irradiation region toward the center thereof as the cooling progresses. The columnar crystal 21 grows from the edge of the irradiation region toward the center to a length of about 1 μm to 3 μm.
Therefore, when the width of the irradiation region by the opening 11 in the lateral direction is set to 2 to 3 μm, crystals grown from the edges of both ends of the irradiation region in the lateral direction grow at the center of the irradiation region in the lateral direction. The edges contact each other and grain boundaries occur. When the width of the irradiation region is set to 5 μm or more, the growth end of the crystal grown from the edge of the irradiation region is not in contact with each other, and a region which is not crystallized occurs near the center of the irradiation region.
Since a crystal with a small grain size is generated, the width of the irradiation region is 5
It is preferably smaller than μm.

Next, the photomask 10 is moved by the driving mechanism 13 so that the irradiation region moves downward in FIG. By this movement of the photomask 10, the edge of the irradiation region by the light passing through the first opening 112 is positioned substantially at the center of the already formed crystal 21 in the longitudinal direction. As a result, the irradiation area is changed to the crystal 21.
So that it overlaps the irradiation area when grown. Then, in the moved irradiation region, the opening 1 of the photomask is formed.
Irradiate the passing light of 1. By this irradiation, the portion of the crystal 21 in the irradiation region is again melted and singulated, and the growth end of this crystal reaches the center of the irradiation region in the lateral direction,
As shown in FIG. 5, a crystal 22 having a larger dimension in the longitudinal direction than the crystal 21 obtained by the previous irradiation is obtained.

Further, the photomask 10 is moved to move the position of the irradiation region to a position further below the irradiation region position where the crystal 22 of FIG. 5 is formed and to a position overlapping the irradiation region. Then, the irradiation region is irradiated with laser light to form a crystal 23 having a larger dimension in the longitudinal direction than the crystal 22 as shown in FIG.

The movement of the photomask 10 and the irradiation of the laser beam are repeated to form a crystal 24 as shown in FIG. The longitudinal direction of the crystal 24 is substantially the same as the lateral direction of the irradiation region by the first opening 112, and the longitudinal length of the crystal 24 is the arrangement interval of the first opening 112 in the photomask 10. Is about the same distance as. Due to the crystal 24, the first crystallization region 2 has a lateral length substantially the same as the length of the first opening 112 in the longitudinal direction and a longitudinal length substantially the same as the arrangement interval of the first openings 112.
5, a plurality of first crystallized regions 25 are formed.
Are connected to each other in the lateral direction of the first opening 112.

During the formation of the crystal 24 in the amorphous silicon film 18, the irradiation area of the light passing through the second opening 113 of the photomask moves in the longitudinal direction, and the direction of this movement is the crystal in the irradiation area. It is almost orthogonal to the growth direction. Therefore, depending on the irradiation area by the second opening 113, the area to be crystallized only increases by the distance a shown in FIG.

Next, the photomask 10 is moved to
As shown by the broken line in FIG. 8, the irradiation region 26 by the light passing through the second opening 113 is located in the first crystallization region 25. FIG. 9 is an enlarged view showing the first crystallization region 25 of FIG. In FIG. 8, the crystal 24 in the first crystallized region 25 is schematically shown in a rectangular strip shape.
4 has an elongated polygonal shape in the growth direction as shown in FIG.

Irradiation area 26 shown by the broken line in FIG. 9 is irradiated with laser light to melt crystal 24 in irradiation area 26. When the irradiation of the laser light is completed, the irradiation area 26
The cooling of the melted portion progresses from the edges on both sides in the lateral direction toward the central portion in the lateral direction. As the cooling progresses, as shown in FIG.
As shown in 0, the crystal 28 grows in the lateral direction of the irradiation region. This crystal growth starts from the crystal 24 which is located at both edges of the irradiation region 26 in the lateral direction and crystallized by the light passing through the first opening. The crystal 24 on which this growth is based is elongated in the vertical direction in FIG.
Since it is substantially parallel to the longitudinal direction of No. 6, it is grown in the lateral direction of the irradiation region 26 while maintaining the above-mentioned elongated longitudinal direction length. Therefore, the crystal 28 formed by being irradiated with the light passing through the second opening has a relatively large width orthogonal to the growth direction.

Subsequently, the photomask 10 is moved, and the irradiation region 26 by the second opening is moved in the lateral direction by a distance approximately half the crystal growth length when the crystal 28 of FIG. 10 is formed, It is arranged at the position shown by the broken line in FIG. The irradiation region 26 is irradiated with a laser beam to grow the crystal 28 in FIG.
Get 9. Further, the crystal 29 is moved while the photomask 10 is moved and the irradiation region 26 is irradiated with laser light to maintain the length of the crystal 29 in the direction perpendicular to the growth direction.
Is further grown in the lateral direction of the irradiation region 26 to obtain the crystal 30 of FIG. FIG. 13 is a reduced view of the surface of the amorphous silicon film 18 on which the crystal 30 shown in FIG. 12 is formed.

The movement of the photomask 10 and the irradiation of the irradiation region 26 with the laser beam are further repeated, so that the crystal grown in the irradiation region 26 of the second opening is irradiated in the irradiation region of the adjacent second opening. Connect to an already grown crystal. As a result, a plurality of second crystallized regions 32, 32, ... As shown in FIG. 14 are obtained in the amorphous silicon film 18. The second crystallization region 32 has a length in the vertical direction that is substantially the same as the arrangement interval of the first openings 112 of the photomask, and is also substantially the same as the arrangement interval of the second openings 113. Has a lateral length of. As shown in FIG. 14, the second crystallized regions 32, 32, ... Include horizontal crystal grain boundaries 45, 45, ... That extend in the horizontal direction, and vertical crystal grain boundaries 46 that extend in the vertical direction in FIG. It is surrounded by.

Crystal 34 of the second crystallized region 32
The crystal 24 formed in the first crystallization region 25 of FIG. 7 and having a relatively long length in the longitudinal direction is further crystal-grown in the lateral direction of the crystal 24. Has a relatively large size without interruption. Also, this relatively large size crystal
By the crystallization device, the photomask 10 can be formed relatively easily only by controlling the movement of the photomask 10 by the driving mechanism 13 and the excimer laser light source 1.

FIG. 15 shows that the transistors 41 and 4 are formed in the second crystallization region 32 formed in the silicon film by the crystallization device.
It is a figure which shows the mode that 2, 43 was formed.

The columnar crystals formed by the conventional crystallization apparatus are
Since the length in the crystal growth direction is much larger than the length in the direction perpendicular to the crystal growth, in the thin film having the columnar crystal,
The direction dependence of carrier mobility was large. That is,
Carriers move in the lateral direction of the columnar crystal rather than move in the longitudinal direction of the columnar crystal, so that they cross far more crystal grain boundaries, so that they are affected by diffusion due to the crystal grain boundaries. The carrier mobility was deteriorated, and the carrier mobility was greatly different between the short-side direction and the long-side direction of the columnar crystal, resulting in the direction dependency of the carrier mobility. On the other hand, the crystals 34, 34 formed in the present embodiment
Have relatively large dimensions, and the difference between the length of the crystal in the growth direction and the length in the direction perpendicular to the growth direction is relatively small.
Therefore, the second crystallized region 32 including the crystal 34 is formed.
Has almost no direction dependence of carrier mobility, and good carrier mobility can be obtained in any direction. As a result, the thin film crystallized by the crystallizing device according to the present embodiment can be configured with a high degree of freedom to form a circuit by arranging a transistor or the like with a high degree of freedom without considering the crystallization direction.

In FIG. 15, the transistors 41,
42 and 43 make the direction of the channel connecting the source S and the drain D substantially the same as the crystal growth direction of the second crystallization region 32. The crystal 34 of the second crystallization region 32
Since the horizontal length in FIG. 15 is longer than the vertical length, the carriers move in the horizontal direction of FIG. 15, that is, in the crystal growth direction of the crystal 34, rather than in the vertical direction. The number of crystal grain boundaries is small and the carrier mobility is high. Therefore, the transistors 41, 42, and 43 can operate at higher speed than the channel direction is perpendicular to the crystal growth direction. Since the crystal 34 has a size larger than that of a columnar crystal formed by a conventional crystallization method, even if a transistor is formed with its channel oriented in a direction perpendicular to the crystal growth direction, this transistor is larger than that in a conventional crystal. Can operate at high speed.

Further, the transistors 41, 42, 43
Among them, the transistor 43 formed over the horizontal crystal grain boundary 45 and the transistor 41 formed over the vertical crystal grain boundary 46 are surrounded by the horizontal crystal grain boundary 45 and the vertical crystal grain boundary 46. The transistor 42 formed inside the second crystallized region 32 has less influence on the carrier mobility due to the lateral crystal grain boundary 45 and the vertical crystal grain boundary 46, and thus has good characteristics.

The substrate having the thin film crystallized by the above crystallization device is suitable for the substrate of the liquid crystal display device as the image display device. That is, the pixel electrode is connected to the transistor 42 formed in the thin film crystal 34 and capable of high-speed operation, and the voltage applied to the pixel is controlled by the transistor 42. As a result, the image display unit composed of the above-described pixels can display an image at high speed, thereby obtaining a good contrast with almost no afterimage. Here, when the thin film of the substrate used for the liquid crystal display device is crystallized, the arrangement interval of the second openings 113 of the photomask of the crystallization device (distance k in FIG. 15).
Is preferably approximately the same as the arrangement interval of the pixels of the liquid crystal display device. As a result, the transistor formed for each pixel can be surely formed inside the second crystallization region 32 without crossing the vertical crystal grain boundary 46, so that the operation speed of the pixel can be made high and uniform. A liquid crystal display device capable of stable and high-speed display can be obtained.

Here, the arrangement intervals of the first opening portions 112 of the photomask may be arbitrary intervals, but it is preferable that the arrangement intervals be longer than the dimensions of the transistors formed in the pixels. As a result, it is possible to effectively prevent the lateral crystal grain boundary from overlapping the transistor. However, if the arrangement interval of the first openings 112 becomes too large, the length of the crystallized portion 33 formed by the light passing through the second opening 113 at the lower end of the second crystallized region 32 as shown in FIG. Becomes too large, and the ineffective region where the second crystallized region cannot be formed becomes too large. Therefore, the first opening 11
The arrangement interval of 2 needs to be set in consideration of the area of the invalid region.

In the liquid crystal display device, the display circuit is formed using the transistor formed in the second crystallization region 32 on the same substrate as the substrate on which the pixel driving transistor is formed. Good. Examples of the display circuit include a logic circuit, a sampling circuit, an amplifier circuit, a scan line driver circuit, and a data line driver circuit. These circuits can sufficiently satisfy the required circuit performance by using the transistors formed in the second crystallization region 32 and capable of operating at high speed.
By forming the display circuit on the substrate on which the pixel electrode is formed, it is possible to make the substrate of the liquid crystal display device smaller than connecting a silicon chip on which the display circuit is formed to the substrate as in the related art, Further, the manufacturing process of the liquid crystal display device can be reduced, and the liquid crystal display device can be downsized and the cost can be reduced.

When the thin film is crystallized by the above-mentioned crystallization apparatus, as shown in FIG. 16, a ladder-like pattern is formed on the right side of the rightmost column of the plurality of second crystallized regions 32, 32 ... An ineffective region 52 having a crystallized portion is formed. FIG. 16 is a diagram showing a state in which a thin film of a substrate for a liquid crystal display device is crystallized, and a second crystallization region 32 for forming a display circuit is formed below the pixel formation region 51. ing. In the ladder-shaped crystallization portion of the ineffective region 52, the crystal of the first crystallization region formed by the light passing through the first opening is crystallized by the light passing through the second opening in the right direction of FIG. When growing,
It is formed by the irradiation light that has passed through the first opening at the right end formed on the photomask. Since the second crystallized region due to the second opening is not formed in the invalid region 52, the display circuit cannot be formed.

FIG. 17 is a diagram showing an opening pattern of a photomask capable of reducing the ineffective region having the ladder-shaped crystallized portion. In the opening pattern of this photomask, the length of the first opening 54 in the longitudinal direction is set to the second opening 56.
The length is smaller than half the arrangement interval. When crystallization is performed using a photomask having this opening pattern, a second crystallization region as shown in FIG. 18 is obtained.
Similar to FIG. 16, FIG. 18 is a diagram showing a state in which a thin film of a substrate for a liquid crystal display device is crystallized. As shown in FIG. 18, when the photomask having the opening pattern is used, when the second crystallization region is formed in the second opening 56, the first crystallization region is formed on the right side of the second crystallization region in the rightmost column. Opening 5
The crystallized portion 58 formed in 4 can be made smaller. Therefore, it is possible to reduce an ineffective region where a transistor or the like cannot be formed, and it is possible to increase the number of substrates that can be manufactured at one time, for example, in manufacturing a liquid crystal display device, thereby reducing manufacturing cost.

FIG. 19 is a diagram showing an opening pattern 11 of a photomask 10 included in a crystallization apparatus of another embodiment of the present invention. The same parts as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The photomask 10 is used to crystallize the thin film of the substrate of the liquid crystal display device. The opening pattern has a plurality of elongated first openings 6 arranged substantially in parallel.
, And a plurality of elongated second openings 62, 62 ... Arranged substantially in parallel so as to be located on both sides of the first openings 61, 61. The first opening 61 and the second opening have a length in the lateral direction of about 3 μm.
Is. The plurality of first openings 61, 61 ... Are arranged at intervals of 6 μm. The plurality of second openings 62, 62 ... Are also arranged at an interval of 6 μm from each other. The first opening 61 and the second opening 6
The arrangement interval of 2 is smaller than the arrangement interval of the pixels of the liquid crystal display device formed by using this opening pattern, and also smaller than the size of the transistor connected to the pixel.

FIG. 20 is a diagram showing a crystallization state obtained when the thin film on the substrate is subjected to the first laser irradiation using the photomask. As shown in FIG.
Crystals grow on the thin film in the lateral direction of the irradiation region by the first and second openings 61 and 62.

Next, as shown in FIG. 21, the photomask is driven by the driving mechanism 13 to move the irradiation area by the opening to the position shown by the broken line 64 in the direction shown by the arrow A. The moved irradiation region is irradiated with laser light again to form a crystal as shown in FIG.

In FIG. 22, the length of the first opening 61 in the short-side direction is approximately half of the arrangement interval, so that the first irradiation portion 61 is moved by the laser beam irradiated onto the irradiation region.
Crystallized regions 66, 66 ... In which crystals are continuous in the lateral direction of the irradiation region of the opening 61 are obtained.

Then, as shown in the enlarged view of FIG. 23, the photomask 10 is driven so that the irradiation area by the first opening portion 61 and the second opening portion 62 is shortened by the second opening portion 62. It is moved in the hand direction as indicated by arrow B. As a result, the irradiation area 68 by the opening moves to the position of the broken line, and the irradiation area by the second opening 62 among the moved irradiation areas is the crystallization area formed by the previous laser irradiation. It is located approximately at the center of 66. The moved irradiation area is irradiated with laser light again.

FIG. 24 is a diagram showing a crystallized region formed by laser irradiation of the irradiation region 68. This Figure 2
As shown in FIG. 4, the light passing through the second opening 62 causes the crystals in the crystallization area 66 to move toward the center from the edges 71, 71 on both sides in the lateral direction of the irradiation area of the second opening. Crystals are grown again to form crystals 72, 72 ... Having a relatively large length in the direction orthogonal to the crystal growth direction.

Subsequently, the photomask 10 is driven to further move the irradiation area of the opening 11 in the lateral direction of the irradiation area of the second opening 62. The moving distance of this irradiation region is substantially the same as the crystal growth length obtained by the previous laser irradiation, or a distance smaller than the crystal growth length. The irradiation area after the movement is irradiated with laser light again. As a result, as shown in FIG. 25, the crystal 72 on the opposite side of the previously formed crystal 72 in the moving direction of the irradiation region is grown again in the moving direction of the irradiation region, and the opening 62 is formed. A crystal 73 in which the irradiation region is long in the lateral direction is obtained.

After that, the photomask 10 is further driven to move the irradiation region of the opening 11 to the position shown by the broken line 75, and the laser beam is further irradiated to the moved irradiation region. By repeating the driving of the photomask 10 and the irradiation of the laser light, as shown in FIG. 26, the crystal grown in the irradiation region of the second opening 62 is irradiated in the irradiation region of the adjacent second opening 62. Connect to the formed crystal. As a result, crystals 77, 77 ... With a relatively long length in the crystal growth direction are obtained. This crystal 77, 77
A transistor for driving the pixel electrode and a pixel display circuit are formed in the crystallized region having. Crystal 77
The length in the vertical direction in FIG. 26 is smaller than the size of the transistor but is relatively large, and the size of the crystal in the crystallization region is substantially uniform. Therefore, the plurality of transistors formed in the crystallization region have substantially the same number of intersecting crystal grain boundaries. Therefore, the above-mentioned transistor can obtain a relatively good and substantially uniform carrier mobility. Therefore, it is possible to obtain a liquid crystal display device having stable display characteristics without variations in characteristics. The crystallization apparatus of this embodiment is the photomask 1 described above.
Since the number of times of movement of the first opening 61 of 0 in the width direction is only one, it is possible to easily form a crystal having relatively good characteristics.

FIG. 27 is a diagram showing a portable electronic device according to an embodiment of the present invention. This portable electronic device includes the image display device 81 having a substrate in which the thin film is crystallized by the crystallization device of the above embodiment. The portable electronic device includes a control circuit 82 including an LSI (Large Scale Integrated Circuit) in which a logic circuit and a memory are mixed, a battery 83, an RF (radio frequency) circuit section 84, an antenna section 85, and a signal line 86. And power line 8
7 and 7. The image display device 81 is a transistor provided in the crystal region formed by the crystallization device, controls the voltage applied to the pixel, and constitutes a display circuit for the pixel. Therefore, the image display device 81 is
Since it is small and can be displayed at high speed, the moving image received by the portable electronic device can be displayed with good contrast with almost no afterimage.

The crystallizing device of the above-described embodiment has the driving mechanism 1
Although the photomask 10 is driven by 3, the photomask may be fixed and the substrate may be driven by a driving mechanism that drives the substrate.

Further, in the above embodiment, the size of the opening of the photomask 10 and the size of the irradiation area by the light passing through this opening are substantially the same, but the size of the opening of the photomask and the thin film of the substrate are different. What is the size of the irradiation area that is irradiated?
It does not have to be the same. That is, the photomask is
It may be used as a reticle.

In the above embodiment, the light source of the crystallization device is an excimer laser light source, but the light source of the crystallization device may be a light source that emits light other than laser light.

In the above embodiment, the substrate obtained by crystallizing the thin film by the crystallization device is used for the liquid crystal display device, but it may be used for EL panels other than the liquid crystal display device.

[0094]

As is clear from the above, according to the crystallization apparatus of the present invention, a photomask having a light transmission pattern and a light source for emitting light to the photomask are provided, and the light transmission pattern of the photomask is provided. In the crystallization apparatus for irradiating the thin film on the substrate with the light passing through the substrate to pass through the thin film and crystallize the thin film, the light transmission pattern of the photomask has an elongated first opening and the first opening. Since the thin film has a second elongated opening extending in a direction substantially orthogonal to the extending direction, it is possible to irradiate the thin film with the light passing through the first opening and move the light passing therethrough in the lateral direction. By repeating, a crystal extending in the lateral direction of the irradiation area of the passing light is formed, and the passing light of the second opening is irradiated to the crystal, and the irradiation area of the passing light is changed to the irradiation area of the irradiation area. Move in the lateral direction By repeating the crystal effectively larger size is obtained.

According to the crystallization apparatus of one embodiment, the plurality of first opening portions of the photomask are provided, and the plurality of first opening portions are arranged in parallel with each other at a predetermined interval. Since the second openings of the mask are arranged so as to be located on both sides of the plurality of first openings arranged in parallel, it is possible to easily form a large amount of crystals having a relatively large size.

According to the crystallization apparatus of one embodiment, the irradiation area on the thin film of the first passing light that has passed through the first opening of the photomask is in the lateral direction of the irradiation area of the first passing light. The first moving means for moving the photomask or the substrate and the irradiation area on the thin film of the second passing light which has passed through the second opening of the photomask are arranged so as to be sequentially connected to each other. A second moving unit that moves the photomask or the substrate so that the photomask or the substrate is sequentially moved in the lateral direction of the irradiation region, and when the movement of the photomask or the substrate is stopped by the first and second moving units, While the passing light irradiates the thin film, when the photomask or the substrate is moved by the first and second moving means, the light source and the first transfer unit are arranged so that the passing light from the light source does not irradiate the thin film. Means and a control means for controlling the second moving means, so that crystals are surely grown on the thin film by the first and second passing lights, and an irradiation region of the first and second passing lights is provided. The crystal can be effectively grown in the lateral direction.

According to the crystallization apparatus of one embodiment, the control means controls the first moving means and the light source to cause the thin film on the substrate to move in the longitudinal direction of the irradiation region of the first passing light. A first crystallization region having a width of a length and extending in the lateral direction of the irradiation region of the first passing light is formed, and the second moving means and the light source are controlled to perform the first crystallization. Since the second crystallization region extending from the region in the lateral direction of the irradiation region of the second passing light is formed, the first crystal having a crystal relatively long in the lateral direction of the irradiation region of the first passing light. The crystallized region is formed in a thin film, and the crystal of the first crystallized region is further grown in the lateral direction of the irradiation region of the second passing light to form the second crystallized region. Crystals can be effectively formed.

According to the crystallizing device of one embodiment, the first moving means moves the photo film so that the irradiation regions of the first passing light are sequentially moved so as to overlap each other in the lateral direction in the thin film of the substrate. While moving the mask or the substrate, the second moving means moves the photomask or the substrate so that the irradiation region of the second passing light overlaps in the lateral direction and sequentially moves in the thin film of the substrate. Therefore, the crystal of the thin film is effectively grown in the lateral direction of the irradiation region of the first passing light, and the crystal grown crystal is further grown in the lateral direction of the irradiation region of the second passing light. It is possible to effectively grow the crystal, and to effectively form a crystal which is continuous in the lateral direction of the second passing light and has almost no interruption.

According to the crystallization apparatus of one embodiment, since the length of the first opening of the photomask in the longitudinal direction is not more than half the distance between the second openings, the first opening of the photomask is not formed.
When the crystal grown in the opening is further crystal-grown by the light passing through the second opening, the ineffective region formed by irradiation with the light passing through the first opening can be effectively reduced.

According to the image display device of the first embodiment, since the thin film is crystallized by using the crystallization device, the image display device having good display characteristics can be formed.

According to the crystallization method of the present invention, a step of irradiating a photomask having a light transmission pattern with light and irradiating the thin film on the substrate with the light passing through the light transmission pattern of the photomask. In the crystallization method, a step of moving the photomask or the substrate so that the light passing through the light transmission pattern of the photomask is irradiated to a position to be irradiated on the thin film on the substrate, Since the light transmission pattern of the mask has the elongated first opening and the elongated second opening extending in a direction substantially orthogonal to the extending direction of the first opening, the light source transmitted through the first opening. The thin film is sequentially crystallized by the light passing through the crystal, and the crystallized thin film is further crystallized by the light passing through the second opening in a direction substantially perpendicular to the crystallization direction of the first opening. By the crystal effectively larger size can be formed.

According to the crystallization method of the one embodiment, the first passing light that has passed through the first opening is connected to the irradiation region of the first passing light in the lateral direction of the irradiation region, and the first passing light is applied to the substrate. Irradiating the thin films in order to form a first crystallization region having a width of the longitudinal length of the irradiation region of the first passing light and extending in the lateral direction of the irradiation region of the first passing light. The second crystal passing through the second opening is sequentially irradiated onto the thin film on the substrate so that the irradiation area of the second light is continuous in the lateral direction of the irradiation area, and the first crystal is irradiated. Second in the area
And a step of forming a second crystallized region extending in the lateral direction of the irradiation region of the passing light, the first passing light is
The thin film is sequentially irradiated so that the irradiation regions are continuous in the lateral direction to form a first crystallization region, and the second passing light is applied to the first crystallization region in the lateral direction. Irradiation is sequentially performed so as to form a second crystallization region extending in the lateral direction of the irradiation region of the second passing light from the first crystallization region, thereby effectively forming a crystal having a relatively large size. Can be formed.

According to the crystallization method of one embodiment, when the first crystallization region is formed, the first crystallization region is formed on the thin film on the substrate in the lateral direction of the irradiation region of the first passing light.
When the second crystallization region is formed while simultaneously irradiating the first passing light so that the irradiation regions of the passing light overlap and are continuous, the second passing light of the second passing light is formed in the thin film on the substrate. Since the second passing light is sequentially irradiated in the lateral direction of the irradiation region so that the irradiation regions of the second passing light partially overlap and are continuous, the thin film of the substrate is irradiated with the first passing light. It is possible to form a first crystallized region in which there is almost no crystal discontinuity in the lateral direction of the region, and a second crystal composed of a crystal having a relatively large size is formed from within the first crystallized region.
Crystallized regions can be formed.

According to the image display device of one embodiment, since the thin film is crystallized by the above crystallization method, the image display device having good display characteristics can be formed.

According to the image display device of the first embodiment, since the transistor is formed in the crystallized thin film, the operation of the transistor can be performed at high speed.

According to the image display device of one embodiment, the transistor drives the pixel electrode, so that the image display device can perform high-speed display, and there is almost no afterimage and good contrast can be obtained.

According to the image display device of one embodiment, the thin film includes a plurality of crystallized regions having substantially the same size, and the transistor is formed in each of the crystallized regions. Since the transistor is formed in the crystallized region where grain boundaries are substantially absent, a high speed transistor can be obtained.

According to the image display device of one embodiment, the display circuit having the transistor formed on the crystallization region of the thin film is arranged around the image display region for displaying an image. Since the transistor included in the circuit can operate at high speed, the display circuit can obtain a sufficient operation speed for image display, and as a result, the image display region and the display circuit are integrally formed over the substrate. It is possible to obtain an image display device having a small number of parts, a small size, low cost, and high reliability.

According to the image display device of one embodiment, the display circuit is composed of a plurality of blocks, and the plurality of blocks are formed in the crystallization region. Since the boundary is formed in the crystallized region having substantially no boundary, a display circuit having a sufficient operation speed can be formed.

According to the image display device of one embodiment, the crystallized region has a rectangular shape, and the length of at least one side of the rectangular shape is the distance between the first opening parts or the second opening part. Since it is equal to any one of the mutual intervals, it can be a crystallization region suitable for forming, for example, a transistor connected to a pixel electrode or a pixel display circuit.

According to the portable electronic device of the first embodiment, since the image display device is provided, a small portable electronic device capable of full-color display of moving images can be constructed.

[Brief description of drawings]

FIG. 1 is a diagram showing a crystallization apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a light transmission pattern provided on a photomask 10 of a crystallization device.

FIG. 3 is a diagram showing one row of first openings 112, 112, ... And one second opening 113 among the openings 11 of the photomask.

FIG. 4 is a schematic view showing a columnar crystal 21 formed on the amorphous silicon film 18.

5 is a diagram showing a state in which a laser beam is applied to an irradiation region to form a crystal 22 having a larger dimension in the longitudinal direction than the crystal 21 of FIG.

FIG. 6 is a diagram showing a state in which a laser beam is applied to an irradiation area to form a crystal 23 having a larger dimension in the longitudinal direction than the crystal 22 of FIG.

7 is a crystal 24 having a size larger than that of the crystal 23 of FIG.
FIG. 3 is a diagram showing a state in which the first crystallization region 25 made of the crystal 24 is formed by forming

FIG. 8 is a diagram showing a state in which the photomask 10 is moved to move the irradiation region by the second opening 113 into the first crystallization region 25.

9 is an enlarged view showing a first crystallization region 25 of FIG.

FIG. 10 is a diagram showing a state in which a crystal 28 is formed by irradiating an irradiation region 26 with laser light.

FIG. 11 is a diagram showing a state in which the photomask 10 is moved and the irradiation region 26 of the second opening is moved.

FIG. 12 shows a case where the irradiation region 26 is irradiated with laser light, and FIG.
It is a figure which shows a mode that the crystal 29 of 1 was grown and the crystal 30 was formed.

FIG. 13 is a reduced view of the surface of the amorphous silicon film 18 on which the crystal 30 shown in FIG. 12 is formed.

FIG. 14 is a diagram showing a state in which a plurality of second crystallized regions 32, 32 ... Are formed in the amorphous silicon film 18.

FIG. 15 shows the transistor 4 in the second crystallization region 32.
It is a figure which shows a mode that 1, 42, 43 was formed.

16 is a diagram showing an invalid region 52 formed on the right side of the rightmost column of the second crystallization regions 32, 32, ....

FIG. 17 is a diagram showing an opening pattern of a photomask capable of reducing an invalid area.

18 is a diagram showing a state in which a thin film of a substrate for a liquid crystal display device is crystallized using the photomask having the opening pattern of FIG.

FIG. 19 is a diagram showing an opening pattern 11 of a photomask 10 included in a crystallization device of another embodiment.

20 is a diagram showing a state of crystallization obtained when the first laser irradiation is performed on the thin film of the substrate using the photomask of FIG.

FIG. 21 is a diagram showing a state where the irradiation region of the opening is moved to the position shown by a broken line 64 in the direction shown by arrow A.

22 is a diagram showing a crystal formed by irradiating the irradiation region of FIG. 21 with laser light again.

FIG. 23 is a diagram showing a state in which the irradiation area of the opening is moved in the lateral direction of the second opening 62 as indicated by an arrow B.

24 is a diagram showing a crystallized region formed by laser irradiation of an irradiation region 68 in FIG.

FIG. 25 is a diagram showing a state in which a crystal 72 on the opposite side of the moving direction of the irradiation region among the crystals 72 formed earlier is grown again in the moving direction of the irradiation region to obtain a crystal 73.

FIG. 26 is a diagram showing a state where crystals 77, 77 ... Having a relatively long length in the crystal growth direction are formed by repeating driving of the photomask 10 and irradiation of laser light.

FIG. 27 is a diagram showing a portable electronic device according to an embodiment of the present invention.

[Explanation of symbols]

11 openings 112 First opening 113 Second opening

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/336 H01L 29/78 627G 29/786 F term (reference) 2H092 JA24 KA05 MA14 MA30 NA21 NA25 NA27 NA29 PA07 5C094 AA43 BA03 DA14 DA15 FB14 5F052 AA02 BA01 BA12 BB01 BB02 BB07 DA02 JA01 5F110 AA01 AA30 BB01 DD02 GG02 GG13 GG25 GG42 GG43 GG45 NN72 PP03 PP05 PP06 PP23 PP24 PP29 5G435 AAEE CC09EE33 H0913

Claims (18)

[Claims] 1. A photomask having a light transmission pattern, and a light source for emitting light to the photomask, wherein light passing through the light transmission pattern of the photomask is applied to a thin film on a substrate. In the crystallizing device for crystallizing the thin film, the light transmission pattern of the photomask has an elongated first opening and an elongated second opening extending in a direction substantially orthogonal to a direction in which the first opening extends. A crystallizing device having: 2. The crystallization apparatus according to claim 1, wherein the photomask includes a plurality of the first openings, and the plurality of first openings are arranged in parallel with each other at a predetermined interval, The crystallization device wherein the second openings of the photomask are arranged so as to be located on both sides of the plurality of first openings arranged in parallel. 3. The crystallization device according to claim 1, wherein the irradiation area of the first passing light that has passed through the first opening of the photomask on the thin film is the irradiation area of the first passing light. A first moving unit that moves the photomask or the substrate so as to sequentially connect in the lateral direction, and an irradiation region on the thin film of the second passing light that has passed through the second opening of the photomask, the second passing portion. Second moving means for moving the photomask or the substrate so as to be successively arranged in the lateral direction of the light irradiation region, and the light source for stopping the movement of the photomask or the substrate by the first and second moving means. From the light source and the light source so that the passing light from the light source does not irradiate the thin film when the photomask or the substrate is moved by the first and second moving means. A crystallization apparatus comprising: a first moving means and a control means for controlling the second moving means. 4. The crystallization apparatus according to claim 3, wherein the control unit controls the first moving unit and the light source to cause the thin film on the substrate to move the irradiation region of the first passing light. Forming a first crystallization region having a width of the longitudinal direction and extending in the lateral direction of the irradiation region of the first passing light;
The first moving means and the light source are controlled to control the first moving means.
A crystallization device characterized by forming a second crystallization region extending from the crystallization region in a lateral direction of the irradiation region of the second passing light. 5. The crystallizing device according to claim 4, wherein the first moving means sequentially moves the irradiation regions of the first passing light in the thin film of the substrate so as to overlap each other in the lateral direction. While moving the photomask or the substrate, the second moving means moves the photomask or the substrate so that the irradiation region of the second passing light overlaps in the lateral direction in the thin film of the substrate and moves sequentially. A crystallization device characterized by being moved. 6. The crystallizing device according to claim 1, wherein a length of the first opening of the photomask in a longitudinal direction is equal to or less than a half of a distance between the second openings. A crystallization device characterized by having a length. 7. An image display device comprising a substrate obtained by crystallizing a thin film using the crystallization device according to claim 1. Description: 8. A step of irradiating a photomask having a light-transmitting pattern with light, and irradiating the thin film on the substrate with the light passing through the light-transmitting pattern of the photomask, and the light-transmitting pattern of the photomask. In the crystallization method, which comprises a step of moving the photomask or the substrate so that the passing light that has passed through is irradiated to a position to be irradiated on the thin film on the substrate, the light transmission pattern of the photomask is elongated A crystallization method comprising: a first opening and an elongated second opening extending in a direction substantially orthogonal to a direction in which the first opening extends. 9. The crystallization method according to claim 8, wherein the first passing light that has passed through the first opening is connected to an irradiation region of the first passing light in a lateral direction of the irradiation region. The thin films on the substrate are sequentially irradiated to form a first crystallization region having a width of the longitudinal length of the irradiation region of the first passing light and extending in the lateral direction of the irradiation region of the first passing light. And a step of irradiating the thin film on the substrate with the second passing light that has passed through the second opening so that the irradiation area of the second passing light is continuous in the lateral direction of the irradiation area. And a step of forming a second crystallized region extending from one crystallized region in the lateral direction of the irradiation region of the second passing light, the light irradiation method. 10. The crystallization method according to claim 8 or 9, wherein in forming the first crystallization region, in the thin film on the substrate, in a lateral direction of the irradiation region of the first passing light, The first passing light is sequentially irradiated so that the irradiation regions of the first passing light partially overlap with each other to be continuous, and when the second crystallization region is formed, the second thin film on the substrate is A crystallization method comprising sequentially irradiating the second passing light so that the irradiation regions of the second passing light are partially overlapped and continuous in the lateral direction of the irradiation region of the passing light. 11. An image display device comprising a substrate having a thin film crystallized by the crystallization method according to any one of claims 8 to 10. 12. The image display device according to claim 7, wherein a transistor is formed in a crystallization region of the thin film. 13. The image display device according to claim 12, wherein the transistor drives a pixel electrode. 14. The image display device according to claim 12, wherein the thin film includes a plurality of crystallized regions having substantially the same size, and the transistor is formed in each of the crystallized regions. An image display device characterized by being provided. 15. The image display device according to claim 12, further comprising a transistor formed on the crystallized region of the thin film, around the image display region for displaying an image. An image display device comprising a circuit. 16. The image display device according to claim 15, wherein the display circuit comprises a plurality of blocks, and the plurality of blocks are formed in the crystallization region. apparatus. 17. The image display device according to claim 14, wherein the crystallized region has a rectangular shape, and at least one side of the rectangular shape has a length equal to that of the first opening. Interval, or
An image display device characterized in that it is substantially equal to any one of the intervals between the second openings. 18. A portable electronic device comprising the image display device according to claim 12.