JP2001296817A - Flat panel display and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat panel display which is uniform in the characteristics of respective TFTs for driving pixel parts and a method for manufacturing the same. SOLUTION: A thin amorphous silicon film formed on a substrate is irradiated with a laser beam of a rectangular shape having energy density of <=550 mJ/cm2 at <=20 shots. The thin amorphous silicon film is then subjected to annealing treatment, by which the thin amorphous silicon film is crystallized and the TFTs for driving the pixel parts are formed. As a result, the crystal grain diameter of the polycrystalline silicon constituting the TFTs for driving the pixel parts is suppressed and the characteristics of the respective TFTs for driving the pixel parts are made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display and a method of manufacturing the same, and more particularly, to a flat panel display having uniform characteristics of each TFT for driving a pixel portion and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels have been widely used as display devices for various electronic devices. At present, as a liquid crystal display panel, switching elements formed in each pixel of a display unit are turned on / off.
An active matrix type that performs switching of pixels is mainly used.

In such an active matrix type liquid crystal display panel, in recent years, a film having a good film quality can be uniformly formed over a large area, and therefore, the pixel switching element is formed of an amorphous silicon thin film. TFTs are being used.

However, since amorphous silicon has low carrier mobility, there is a problem in that, when TFTs are manufactured using the amorphous silicon as it is, the current driving capability of the TFTs becomes extremely low. In particular, a TFT of a driving unit including a horizontal scanning circuit unit and a vertical scanning circuit unit is required to have a higher driving capability than a TFT for driving a pixel unit due to a demand for high-speed driving. In the case where the TFT for driving the pixel portion is formed on the same substrate, the driving capability of the TFT of the driving portion becomes largely insufficient if amorphous silicon is used.

For this reason, it is common practice to form an amorphous silicon thin film on a substrate and then anneal the amorphous silicon thin film to crystallize silicon and improve the film quality. As a method of such annealing, a method of irradiating an amorphous silicon thin film with a pulse laser in an ultraviolet wavelength range such as an excimer laser (laser annealing) is known.

As described above, by performing the annealing process, the amorphous silicon thin film is crystallized, and the mobility is increased. As a result, the driving capability of the TFT is increased, and high-speed operation becomes possible.

[0007]

On the other hand, the TFT for driving the pixel section is required to have uniform characteristics, unlike the TFT for the driving section, and the conventional approach is employed. Thus, there is a problem that it is difficult to make the characteristics of the TFT for driving the pixel portion uniform.

[0008] In addition to liquid crystal display panels, TF
A similar problem occurs in a flat panel display such as an EL display panel using T as a pixel switching element.

Accordingly, an object of the present invention is to provide a flat panel display in which the characteristics of each TFT for driving a pixel portion are uniform, and a method of manufacturing the same.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by a flat panel display in which the crystal grain size of the polycrystalline silicon constituting the TFT for driving the pixel portion is smaller than the channel length and channel width of the TFT.

According to the study of the present inventor, although the TFT formed in the driving section is required to operate at a high speed, the TFT for driving the pixel section is not required to operate as fast as the TFT in the driving section. Therefore, the polycrystalline silicon thin film constituting the TFT for driving the pixel portion does not require much mobility, and from the viewpoint of improving the image quality, the crystal grain size of the polycrystalline silicon thin film is rather small and uniform. TF
It has been found desirable to have a T characteristic,
According to the present invention, since the crystal grain size of the polycrystalline silicon constituting the TFT is smaller than the channel length and channel width of the TFT, it is possible to obtain a flat panel display in which the characteristics of each TFT for driving the pixel portion are uniform. Becomes

In a preferred embodiment of the present invention, the crystal grain size of the polycrystalline silicon is 1/15 to 1 of one of the channel length and the channel width of the TFT.
/ 3.

According to a preferred embodiment of the present invention, the crystal grain size of the polycrystalline silicon is formed to be 1/15 to 1/3 of one of the channel length and the channel width of the TFT. Therefore, it is possible to make the characteristics of each TFT uniform while securing a sufficient driving capability as a TFT for driving the pixel portion.

In a further preferred aspect of the present invention, the crystal grain size of the polycrystalline silicon is 1/1 of one of the channel length and the channel width of the TFT.
It is formed at 0 to 1/5.

In a further preferred aspect of the present invention, the polycrystalline silicon is formed by annealing the amorphous silicon with a rectangular laser beam.

In a further preferred aspect of the present invention, the polycrystalline silicon is formed by annealing the amorphous silicon by irradiating the rectangular laser beam with not more than 20 shots.

In a further preferred aspect of the present invention, the energy density of the rectangular laser beam is 5%.
It is set to 50 mJ / cm ² or less.

In a further preferred aspect of the present invention, the rectangular laser beam has an energy density of 4
It mJ / cm ² without being set to 500 mJ / cm ^2.

In a further preferred aspect of the present invention, the rectangular laser beam is constituted by an excimer laser beam.

In a further preferred aspect of the present invention, the excimer laser beam comprises a XeCl excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam.
It is constituted by an excimer laser beam selected from the group consisting of excimer laser beams.

In a further preferred embodiment of the present invention, the TFT has a channel length and a channel width of 1 μm or more.

In a further preferred aspect of the present invention, at least one of the channel length and the channel width of the TFT is formed to be about 2 μm.

In a further preferred aspect of the present invention, the amorphous silicon is formed by a thin film formed on a substrate.

In a further preferred aspect of the present invention, the amorphous silicon thin film has a thickness of 70 nm.
It is formed as follows.

In a further preferred aspect of the present invention, the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate.

The object of the present invention is also to irradiate amorphous silicon with a rectangular laser beam having an energy density of 550 mJ / cm ² or less for 20 shots or less and to anneal the amorphous silicon to polycrystallize it. This is achieved by a flat panel display in which a TFT for driving a pixel portion is formed.

According to the present invention, amorphous silicon is irradiated with a rectangular laser beam having an energy density of 550 mJ / cm ² or less for 20 shots or less, the amorphous silicon is annealed to be polycrystallized, and the pixel portion is driven. Is formed, the crystal grain size of silicon constituting the TFT does not become so large,
Since the variation in the crystal grain size of silicon is small, it is possible to obtain a flat panel display in which the characteristics of each TFT for driving the pixel portion are uniform.

In a preferred embodiment of the present invention, the energy density of the rectangular laser beam is 400 m
J / cm ² to 500 mJ / cm ² is set.

In a further preferred embodiment of the present invention, the TFT has a channel length and a channel width of 1 μm or more.

In a further preferred aspect of the present invention, at least one of the channel length and the channel width of the TFT is formed to be about 2 μm.

In a further preferred aspect of the present invention, the rectangular laser beam is constituted by an excimer laser beam.

In a further preferred aspect of the present invention, the excimer laser beam is a XeCl excimer laser beam, a KrF excimer laser beam, or an ArF excimer laser beam.
It is constituted by an excimer laser beam selected from the group consisting of excimer laser beams.

In a further preferred aspect of the present invention, the amorphous silicon is formed by a thin film formed on a substrate.

In a further preferred aspect of the present invention, the amorphous silicon thin film has a thickness of 70 nm.
It is formed as follows.

[0035] In a further preferred aspect of the present invention, the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate.

The object of the present invention is also to provide an amorphous silicon thin film formed on a substrate with a thickness of 550 mJ / cm ^2.
A rectangular laser beam having the following energy density is irradiated for 20 shots or less, the amorphous silicon thin film is annealed to be polycrystallized, and a T
This is achieved by a method for manufacturing a flat panel display, which comprises forming an FT.

According to the present invention, the amorphous silicon formed on the substrate is irradiated with a rectangular laser beam having an energy density of 550 mJ / cm ² or less for 20 shots or less, and the amorphous silicon is annealed. Since the TFTs for driving the pixel portion are crystallized, the crystal grain size of the silicon constituting the TFT does not become so large and the variation in the crystal grain size of the silicon is small. It is possible to obtain a flat panel display with uniform characteristics.

In a preferred embodiment of the present invention, the energy density of the rectangular laser beam is 400 m
J / cm ² to 500 mJ / cm ² is set.

In a further preferred aspect of the present invention, the rectangular laser beam is constituted by an excimer laser beam.

In a further preferred aspect of the present invention, the excimer laser beam comprises a XeCl excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam.
It is constituted by an excimer laser beam selected from the group consisting of excimer laser beams.

In a further preferred aspect of the present invention, the laser beam is irradiated so that the TFT has a channel length and a channel width of 1 μm or more, thereby forming a TFT for driving a pixel portion.

In a further preferred aspect of the present invention, the TFT for driving a pixel portion is formed by irradiating the laser beam so that at least one of a channel length and a channel width of the TFT is about 2 μm. You.

In a further preferred aspect of the present invention, the amorphous silicon thin film has a thickness of 70 nm.
It is formed as follows.

In a further preferred embodiment of the present invention, the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate.

[0045]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First, the principle that amorphous silicon is crystallized by annealing will be described with reference to FIG.

FIG. 1 shows that an amorphous silicon thin film
eCl excimer laser (resonance wavelength 308 nm)
It is a figure which shows the temperature change at the time of irradiating over 0 nsec.

As shown in FIG. 1, when the excimer laser is irradiated on the amorphous silicon thin film, the temperature of the amorphous silicon thin film starts to rise and reaches about 1100 ° C.
Then, the amorphous silicon thin film starts to melt. At this time, the temperature of the amorphous silicon thin film is substantially about 11
The temperature remains at 00 ° C. When the amorphous silicon thin film is completely melted, the temperature of the amorphous silicon thin film rises again. At this point, when the irradiation of the excimer laser is stopped, the cooling of the amorphous silicon thin film is started. When the temperature of the thin film reaches about 1420 ° C. by cooling, silicon crystals begin to grow. At this time, the temperature of the amorphous silicon thin film changes substantially at about 1420 ° C. Once the amorphous silicon has completely solidified,
The temperature drops.

Through such a process, the crystallization of the amorphous silicon thin film progresses, and by repeatedly performing the crystallization a plurality of times, a polycrystalline silicon film having a desired grain size can be obtained.

FIG. 2 is a schematic perspective view of a laser annealing apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 2, the laser annealing apparatus 1 has a laser oscillator 11 for generating a XeCl excimer laser beam 21 (resonance wavelength 308 nm). In this embodiment, the laser oscillator 11 is configured to generate a rectangular XeCl excimer laser beam 21. X emitted from the laser oscillator 11
In the optical path of the eCl excimer laser beam 21, the reflecting mirror 3
XeCl excimer laser beam 2
1 is reflected by the reflecting mirror 31 and guided to the attenuator 12.

In the optical path of the XeCl excimer laser beam 21 having passed through the attenuator 12, a reflecting mirror 32 is provided. The XeCl excimer laser beam 21 is reflected by the reflecting mirror 32, and scans the XeCl excimer laser beam 21 in the x direction. The laser beam enters the reflecting mirror 33 attached to the laser scanning mechanism 39 and is scanned in the x direction. The reflecting mirror 32 is attached to a laser scanning mechanism 40 that scans the XeCl excimer laser beam 21 in the y direction.

A reflecting mirror 34 is provided in the optical path of the XeCl excimer laser beam 21 reflected by the reflecting mirror 33, and the XeCl excimer laser beam 21 is reflected by the reflecting mirror 34 and guided to the beam homogenizer 14. The beam homogenizer 14 of the XeCl excimer laser beam 21 makes the laser high intensity in the radial direction of the light beam substantially uniform.

XeC passing through the beam homogenizer 14
In the optical path of the excimer laser beam 21, the chamber 1
5 are arranged. Inside the chamber 15, a stage 16 on which a glass substrate 91 having an amorphous silicon thin film (not shown) formed on the surface is mounted. In addition, a transmission window 41 formed of quartz glass that transmits the XeCl excimer laser beam 21 is provided in an upper part of the chamber 15.

The XeCl excimer laser beam 21 having entered the chamber 15 is converted into an amorphous silicon thin film (not shown) formed on a glass substrate 91 by a laser scanning mechanism 39 and a laser scanning mechanism 40 in the x-axis direction and the y-axis direction. The XeCl excimer laser beam 21 is irradiated on the entire surface of the amorphous silicon thin film formed on the glass substrate 91.

The laser annealing apparatus according to the preferred embodiment of the present invention configured as described above performs an annealing process on an amorphous silicon film formed on a glass substrate 91 to polycrystallize it as follows. And a TFT for driving the pixel portion of the liquid crystal display panel.

From the laser oscillator 11, 400 mJ / cm
² to 550 mJ / cm ² , preferably 450 mJ
/ To cm ² no rectangular XeCl excimer laser beam 21 is emitted with an energy density of 500 mJ / cm ^2, XeCl excimer laser beam 21 by the optical system, is led into the chamber 15.

The XeCl excimer laser beam 21 is emitted by a laser scanning mechanism 39 and a laser scanning mechanism 40.
The amorphous silicon thin film formed on the glass substrate 91 is scanned in the x-axis direction and the y-axis direction, and the entire surface of the amorphous silicon thin film is irradiated with the XeCl excimer laser beam 21.

In this embodiment, a rectangular XeCl
The excimer laser beam 21 has a continuous irradiation area by a laser scanning mechanism 39 and a laser scanning mechanism 40.
The amorphous silicon thin film is moved stepwise in the x-axis direction and the y-axis direction so as to overlap in a certain range, and each region of the amorphous silicon thin film is irradiated with the XeCl excimer laser beam 21 of 20 shots or less. It is configured to receive irradiation.

In the present embodiment, the crystal grain size of the polycrystalline silicon of the TFT for driving the pixel portion is set smaller than the channel length and channel width of the TFT so that the TFT for driving the pixel portion of the liquid crystal display panel has uniform characteristics. The amorphous silicon film is annealed by the XeCl excimer laser beam 21 to be polycrystallized so as to be smaller.

Preferably, in order to make the characteristics of the pixel portion driving TFT uniform while securing the mobility equal to or higher than a predetermined value,
The crystal grain size of the polycrystalline silicon of the pixel portion driving TFT is T
1/15 to 1/3 of one of the channel length and channel width of the FT, more preferably 1/10 to 1 of one of the channel length and channel width
/ 5 so that the amorphous silicon film is made of XeC
Annealing is performed by the excimer laser beam 21.

In this embodiment, the TFT for driving the pixel portion of the liquid crystal display panel has a channel length of about 2 μm and a channel width of about 2 μm.

[0063]

EXAMPLES Examples will be given below to further clarify the effects of the present invention.

Example 1 An amorphous silicon thin film having a thickness of 40 nm was formed on a glass substrate, and the amorphous silicon thin film was annealed by changing the number of shots using a laser annealing apparatus shown in FIG. The crystal grain size of the obtained polycrystalline silicon was measured.

Here, the laser beam is 500 m
A XeCl excimer laser beam having an energy density of J / cm ² was used, and the pulse width was 10 Hz.

The measurement results are shown in FIG.

As shown in FIG. 3, as the number of shots irradiated with the XeCl excimer laser beam increases, the crystal grain size of the obtained polycrystalline silicon increases, the variation in the crystal grain size increases, and the uniform characteristics can be improved. For a TFT for driving a pixel portion of a liquid crystal display panel that requires
It has been found that the number of shots of the Cl excimer laser beam is desirably 20 or less.

The channel length and channel width of the TFT for driving the pixel portion of the liquid crystal display panel are each 1 μm.
m or more, usually about 2 μm.
It has been found that the crystal grain size of silicon constituting the TFT for driving the pixel portion is desirably smaller than the channel length and channel width of the TFT.

Example 2 An amorphous silicon thin film having a thickness of 40 nm was formed on a glass substrate, and the energy density of a laser beam was changed by using a laser annealing apparatus shown in FIG.
The amorphous silicon thin film was annealed, and the crystal grain size of the obtained polycrystalline silicon was measured.

Here, the laser beam is XeCl
Using an excimer laser beam, pulse width 1 Hz, 10
Irradiated over shots.

The measurement results are shown in FIG. In FIG. 4, the horizontal axis represents the energy density of the used XeCl excimer laser beam.

As shown in FIG. 4, when the energy density of the energy beam is 550 mJ / cm ² or less, the crystal grain size of the obtained silicon increases, and the throughput of the annealing process is improved. Energy density of 400 mJ / cm ² to 5
It was found that the effect was remarkable at 00 mJ / cm ² .

The present invention is not limited to the above-described embodiments and examples, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. It goes without saying that it is included.

For example, in the above embodiment, the TFT for driving the pixel portion of the liquid crystal display panel is generated, but the present invention is not limited to this.
The present invention can be widely applied to generation of a TFT for driving a pixel portion of a flat display panel, such as a TFT for driving a pixel portion of a display panel.

In the above embodiment, the XeCl excimer laser beam 21 having a resonance wavelength of 308 nm is used.
8 nm), ArF excimer laser beam (resonance wavelength 19
3 nm) An excimer laser beam such as an excimer laser beam may be used.
Other laser beams, and energy beams such as an electron beam and an infrared beam can also be used.

Further, in the above embodiment, an amorphous silicon thin film having a thickness of 40 nm is formed on a glass substrate, and an annealing process is performed using a XeCl excimer laser beam. Is not limited to 40 nm, and preferably 70 nm or less.

In the above embodiment, the amorphous silicon thin film is formed on the glass substrate 91. However, instead of the glass substrate 91, the amorphous silicon thin film is formed on another substrate such as a plastic substrate. You may.

Further, in the above embodiment, the laser annealing apparatus 1 shown in FIG. 2 is used to irradiate the XeCl excimer laser beam 21 to the amorphous silicon thin film. However, the present invention is not limited to this. Instead, another laser annealing apparatus can be used. For example, in the laser annealing apparatus 1 shown in FIG. 2, the XeCl excimer laser 21 is scanned stepwise in the x-axis direction and the y-axis direction by the laser scanning mechanisms 39 and 40. With the optical path fixed, the stage 16
The amorphous silicon thin film may be scanned by moving in the direction and the y direction.

In the above embodiment, XeCl
Although the amorphous silicon thin film is scanned stepwise by the excimer laser beam 21, the XeCl excimer laser 21 can be collectively irradiated on the entire surface of the amorphous silicon thin film even when the amorphous silicon thin film is continuously scanned. .

Further, in the above embodiment, the rectangular XeCl excimer laser beam 21 is applied to the glass substrate 9.
1, the XeCl excimer laser beam 21 is not limited to a rectangular shape, but may be a circular or linear XeC excimer laser beam.
An excimer laser beam 21 may be used.

[0081]

According to the present invention, each TF for driving the pixel portion is provided.
It is possible to provide a flat panel display having a uniform T characteristic and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 shows an amorphous silicon thin film with XeCl
It is a figure which shows the temperature change when excimer laser is irradiated for 160 nsec.

FIG. 2 is a schematic perspective view of a laser annealing apparatus according to a preferred embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the number of shots of a XeCl excimer laser beam having an energy density of 500 mJ / cm ² and the crystal grain size of an amorphous silicon thin film.

FIG. 4 is a graph showing the relationship between the energy density of a XeCl excimer laser beam and the crystal grain size of an amorphous silicon thin film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Annealing apparatus 1 11 Laser oscillator 12 Attenuator 14 Beam homogenizer 15 Chamber 16 Stage 21 XeCl excimer laser 31-34 Reflection mirror 39, 40 Laser scanning mechanism 41 Transmission window 91 Glass substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/336 H01L 29/78 627G (72) Inventor Hideharu Nakajima 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation F term (reference) 2H092 JA24 JA31 JA32 KA04 KA05 MA30 NA24 PA01 5C094 AA03 BA03 BA43 CA19 EA04 EA07 EB05 GB10 5F052 AA02 AA03 AA06 BA18 BA20 BB07 DA02 JA01 5F110 AA30 BB02 GG02 GG02 GG02 GG02 PP05 PP06 5G435 AA01 BB12 CC09 HH12 KK05 KK09 KK10

Claims (31)

[Claims] 1. A flat panel display, wherein a crystal grain size of polycrystalline silicon constituting a TFT for driving a pixel portion is smaller than a channel length and a channel width of the TFT. 2. The method according to claim 1, wherein the crystal grain size of the polycrystalline silicon is 1/15 to 1/3 of one of the channel length and the channel width of the TFT.
A flat panel display according to claim 1. 3. The TFT according to claim 2, wherein a crystal grain size of said polycrystalline silicon is 1/10 to 1/5 of one of a channel length and a channel width of said TFT.
A flat panel display according to claim 1. 4. The polycrystalline silicon according to claim 1, wherein the amorphous silicon is formed by annealing the amorphous silicon with a rectangular laser beam. Flat panel display. 5. The polycrystalline silicon according to claim 4, wherein the amorphous silicon is formed by annealing the amorphous silicon by irradiation of the rectangular laser beam of 20 shots or less. Flat panel display. 6. The flat panel display according to claim 4, wherein an energy density of the rectangular laser beam is set to 550 mJ / cm ² or less. 7. The energy density of the rectangular laser beam is 400 mJ / cm ² to 500 mJ / cm ^2.
The flat panel display according to claim 6, wherein: 8. The flat panel display according to claim 5, wherein the rectangular laser beam is constituted by an excimer laser beam. 9. An excimer laser beam, comprising: XeCl
9. The flat panel display according to claim 8, comprising an excimer laser beam selected from the group consisting of an excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam. 10. The flat panel display according to claim 1, wherein the TFT has a channel length and a channel width of 1 μm or more. 11. The flat panel display according to claim 10, wherein at least one of a channel length and a channel width of the TFT is formed to be about 2 μm. 12. The flat panel display according to claim 4, wherein the amorphous silicon is formed by a thin film formed on a substrate. 13. The flat panel display according to claim 12, wherein the amorphous silicon thin film has a thickness of 70 nm or less. 14. The flat panel display according to claim 12, wherein the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate. 15. 550 mJ of amorphous silicon
Wherein a rectangular laser beam having an energy density of not more than 20 shots / cm ^{2 is} irradiated for 20 shots or less, the amorphous silicon is annealed to be polycrystallized, and a TFT for driving a pixel portion is formed. Panel display. 16. The energy density of the rectangular laser beam is 400 mJ / cm ² to 500 mJ / cm ^2.
The flat panel display according to claim 15, wherein: 17. The flat panel display according to claim 15, wherein the rectangular laser beam is constituted by an excimer laser beam. 18. The method according to claim 18, wherein the excimer laser beam is XeC
18. The flat panel display according to claim 17, comprising an excimer laser beam selected from the group consisting of an excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam. 19. The flat panel display according to claim 15, wherein a channel length and a channel width of each of the TFTs are formed to be 1 μm or more. 20. The flat panel display according to claim 19, wherein at least one of a channel length and a channel width of the TFT is formed to be about 2 μm. 21. The flat panel display according to claim 15, wherein the amorphous silicon is formed by a thin film formed on a substrate. 22. The flat panel display according to claim 21, wherein the amorphous silicon thin film has a thickness of 70 nm or less. 23. The flat panel display according to claim 21, wherein the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate. 24. An amorphous silicon thin film formed on a substrate is irradiated with a rectangular laser beam having an energy density of 550 mJ / cm ² or less for 20 shots or less, and the amorphous silicon thin film is annealed to be polycrystalline. And forming a TFT for driving a pixel portion. 25. An energy density of the rectangular laser beam is 400 mJ / cm ² to 500 mJ / cm ^2.
The method for manufacturing a flat panel display according to claim 24, wherein: 26. The method for manufacturing a flat panel display according to claim 24, wherein the rectangular laser beam is constituted by an excimer laser beam. 27. The excimer laser beam comprises XeC
27. The method for manufacturing a flat panel display according to claim 26, comprising an excimer laser beam selected from the group consisting of an excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam. 28. The flat panel display according to claim 24, wherein the laser beam is irradiated such that a channel length and a channel width of the TFT are each 1 μm or more. Production method. 29. The method according to claim 28, wherein the laser beam is irradiated so that at least one of a channel length and a channel width of the TFT is about 2 μm. 30. The method of manufacturing a flat panel display according to claim 24, wherein said amorphous silicon thin film has a thickness of 70 nm or less. 31. The method for manufacturing a flat panel display according to claim 24, wherein the substrate is constituted by a substrate selected from the group consisting of a glass substrate and a plastic substrate. .