JP2001257173A - Method and device for reforming energy beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage caused by applying laser beams to a part being different from a substrate in a method and device for applying the laser beams to the substrate that is represented by amorphous silicon for reforming the substrate. SOLUTION: In a beam shield 8, an opening is formed corresponding to an amorphous silicon thin film 5 that covers a stage 7 and is formed on the surface of a glass substrate 6 that is placed on the stage 7. The beam shield 8 moves in linking with the stage 7. By the beam shield 8, a laser beam 2 is made simply to irradiate the amorphous silicon thin film 5, thus preventing the stage 7 from being exposed to the laser beam 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy beam reforming method and an energy beam reforming apparatus, and more particularly, to irradiating an energy beam to shift a region of a substrate to be reformed stepwise. In addition, when a predetermined region of a substrate is modified by irradiating an energy beam, an improved energy beam modification method and an energy beam modification method capable of irradiating an energy beam only to a region to be modified are provided. It concerns the device.

[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. TFT (thin film transistor)
Is being used.

However, amorphous silicon has a low carrier mobility. Therefore, if a TFT is manufactured by using the amorphous silicon as it is, there is a problem that the current driving capability of the TFT becomes extremely low.

For this reason, it is common practice to form amorphous silicon on a substrate and then anneal the amorphous silicon to improve the film quality of the silicon. 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.

Conventionally, as such a laser annealing method, a linear laser beam having a width smaller than 800 μm is applied to an amorphous silicon silicon thin film.
In general, the same portion of the amorphous silicon thin film is irradiated over several shots by relatively moving a linear laser beam, and the entire amorphous silicon thin film is annealed and crystallized. Such a technique is described, for example, in JP-A-10-199809.

However, when the amorphous silicon silicon thin film is subjected to laser annealing as described above, the laser beam is narrow, so that the throughput is low and uniform irradiation in the scanning direction is difficult.
Further, there is a disadvantage that the crystal grain size is not uniform between the adjacent irradiated portions. For this reason, a method has been proposed in which the shape of the laser beam is rectangular rather than linear, and annealing is performed by sequentially irradiating the amorphous silicon thin film with a rectangular high-power laser beam.

When a rectangular high-power laser beam is applied to an amorphous silicon thin film, a polycrystalline silicon film having a large crystal grain size is formed, so that a TFT having high carrier mobility can be manufactured. (KH Lee et al., Gigantic)
Crystal grain by excimer
laser with long pulse dur
ation of 200ns and application
ation to TFT, presentedin
ISPSA-98. (Seoul), and a TFT with a small variation in threshold value can be manufactured (Taka Noguchi, high-temperature short-time annealing effect on fine poly-Si TFTs (ELA and RTA), IEICE Technical Report SDM 92-171).
(1992-03)).

[0009]

However, when a rectangular laser beam is sequentially irradiated by a so-called step-and-repeat method, an outer peripheral portion (end face) of the region irradiated with the rectangular laser beam is used. , It is often recognized that abnormal crystals are formed. Therefore, when the outer peripheral portion of the region irradiated with the rectangular laser beam is not used for manufacturing the TFT, no problem occurs. However, when this portion is used for manufacturing the TFT, an abnormal crystal causes a problem. However, there has been a problem that the characteristics greatly vary and the reliability thereof is significantly impaired.

In order to avoid such a problem, the rectangular laser beam is irradiated by irradiating the same region twice or more while gradually shifting the region of the amorphous silicon thin film to be irradiated with the rectangular laser beam. It has been proposed to reduce the occurrence of abnormal crystals occurring in the outer peripheral portion of the region irradiated with, but in this method, it is difficult to uniformly anneal the amorphous silicon thin film near the outer peripheral portion of the substrate. Met. That is,
If an attempt is made to uniformly anneal the amorphous silicon thin film in the vicinity of the outer peripheral portion of the substrate, the laser beam must be applied to the portion of the substrate where the amorphous silicon thin film is not formed or the region outside the substrate. As a result, there is a problem that the stage on which the substrate is mounted or the substrate itself is damaged, and furthermore, impurities generated by the damage are taken into the silicon thin film, thereby deteriorating the performance of the TFT. For example, when a laser is applied to a portion of a substrate to which an organic substance is attached, the portion is ablated or a gas such as carbon, oxygen, and hydrogen generated by the laser irradiation is melted by laser annealing. There is a risk of being taken into the silicon thin film and deteriorating the film quality.If a laser is applied to the stage on which the substrate is mounted or a member in the annealing chamber, the metal atoms are scattered, and the scattered metal atoms are melted. Conventionally, the amorphous silicon thin film to be irradiated with a rectangular laser beam is shifted stepwise, and the same region is irradiated with the laser beam two or more times. When annealing the silicon thin film, the amorphous silicon thin film near the outer periphery of the substrate is uniformly annealed. It is difficult to Le process.

Hydrophilic treatment of the surface of a tetrafluoroethylene plate using an energy beam, formation of a thin film on a glass plate using an energy beam, densification of a silicon oxide film formed by plasma CVD using an energy beam A similar problem also occurs in the removal of hydrogen gas from amorphous silicon using an energy beam.

Accordingly, the present invention provides a method for modifying a predetermined region of a substrate by irradiating an energy beam and irradiating the energy beam while gradually shifting the region of the substrate to be modified. Only in the areas to be qualified
It is an object of the present invention to provide an improved energy beam reforming method and an energy beam reforming apparatus capable of irradiating an energy beam.

[0013]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A substrate to be modified is placed on a stage, and an opening is formed corresponding to a portion of the substrate to be modified, and the stage is covered with a beam shield having a constant relative positional relationship with the stage. This is achieved by an energy beam modification method in which an energy beam is stepwise shifted to the substrate through the opening, and is sequentially irradiated to modify the substrate.

According to the present invention, an opening is formed corresponding to a portion of the substrate to be modified, and the stage is covered with the beam shield having a constant relative positional relationship with the stage. Since the energy beam is irradiated and the substrate is modified, the energy beam is irradiated only to the portion of the substrate to be modified, and therefore, the portion of the substrate or the stage that does not need to be modified is irradiated with the energy beam, It is possible to reliably and effectively prevent the generation of impurities caused by damaging a portion or stage of the base that does not need to be performed.

In the present invention, the substrate includes not only the substrate itself but also a thin film formed on the substrate.

In a preferred embodiment of the present invention, the energy beam has a rectangular shape.

According to a preferred embodiment of the present invention, since a rectangular energy beam is used, the throughput is improved, and the energy beam is uniformly irradiated in the scanning direction. In this case, it is possible to effectively prevent the crystal grain size from becoming non-uniform.

In a further preferred aspect of the present invention, the energy beam is constituted by an energy beam selected from the group consisting of a laser beam, an electron beam and an infrared beam.

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

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

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

In a further preferred aspect of the present invention, the laser beam has a pulse width of 20 to 300 ns.
c is set.

In a further preferred embodiment of the present invention, the base is constituted by a thin film formed on a substrate.

In a further preferred aspect of the present invention, the thin film is constituted by an amorphous silicon thin film.

According to a further preferred embodiment of the present invention, the energy beam modifying method is used for annealing TFTs of flat panel displays such as a liquid crystal display panel and an electroluminescence display panel by using an annealing treatment of an amorphous silicon thin film. It is possible to obtain a TFT with improved characteristics.

In a further preferred aspect of the present invention, the thin film is constituted by a silicon oxide film.

[0027] In a further preferred aspect of the present invention, the base is constituted by a polytetrafluoroethylene substrate.

In a further preferred embodiment of the present invention, the substrate is constituted by a glass substrate.

In a further preferred embodiment of the present invention, the substrate is constituted by a plastic substrate.

[0030] In a further preferred aspect of the present invention, the stage is configured to be movable, and the beam shield is configured to be movable in conjunction with the stage.

[0031] In a further preferred aspect of the present invention, the beam shield is connected to the stage.

According to a further preferred embodiment of the present invention, since the beam shield is connected to the stage,
The stage and the beam shield can be easily linked and moved.

[0033] In a further preferred aspect of the present invention, the stage and the beam shield are arranged in the chamber.

[0034] In a further preferred aspect of the present invention, the stage is disposed in the chamber, and the beam shield is disposed outside the chamber.

In a further preferred aspect of the present invention, at least a surface of the beam shield is formed of a material that does not ablate with respect to the energy beam.

[0036] In a further preferred aspect of the present invention, at least a surface of the beam shield is formed of a high melting point metal selected from the group consisting of molybdenum, tantalum and tungsten.

[0037] In still another preferred embodiment of the present invention, at least a surface of the beam shield is formed of ceramic.

In a further preferred aspect of the present invention, the base is constituted by a thin film formed on a part of the substrate surface, and the opening of the beam shield corresponds to a portion where the thin film is formed. Thus, the relative positional relationship of the beam shield with respect to the stage is set.

According to a further preferred embodiment of the present invention, the relative position of the beam shield with respect to the stage is set so that the opening of the beam shield corresponds to the portion where the thin film is formed. The surface and the stage are prevented from being irradiated with the energy beam,
Therefore, it is possible to prevent the substrate and the stage from being damaged, and to reliably prevent the reforming process from being adversely affected by impurities generated by the damage.

[0040] In a further preferred aspect of the present invention, the beam shield is disposed within a depth of focus of the energy beam.

In a further preferred aspect of the present invention, the depth of focus of the energy beam is set to 1 mm or more.

In a further preferred aspect of the present invention, the surface of the beam shield is formed so as to diffusely reflect the energy beam.

According to a further preferred embodiment of the present invention, since the surface of the beam shield is formed so as to irregularly reflect the energy beam, the reflected light of the energy beam from the beam shield is focused on a specific portion. In addition, it is possible to effectively prevent the members of the device from being damaged.

In a further preferred aspect of the present invention, the opening of the beam shield is formed in a rectangular shape.

In a further preferred aspect of the present invention, the stage is configured to move by a distance smaller than one side of the rectangular energy beam as one unit.

In a further preferred aspect of the present invention, the stage is configured to be moved with a distance of an integer fraction of one side of the rectangular energy beam as one unit.

In a further preferred aspect of the present invention, the stage is moved so that a distance different from an integer fraction of one side of the rectangular energy beam is set as one unit.

In a further preferred aspect of the present invention, the stage is configured to be moved stepwise in conjunction with the irradiation of the energy beam.

In a further preferred aspect of the present invention, the stage is configured to be continuously moved in conjunction with the irradiation of the energy beam.

In a further preferred embodiment of the present invention, the inside of the chamber is maintained at a reduced pressure.

In a further preferred embodiment of the present invention, the inside of the chamber is filled with an inert gas.

In a further preferred embodiment of the present invention, the inert gas is constituted by a gas selected from the group consisting of nitrogen and an inert gas.

The object of the present invention is also an energy beam reforming apparatus for irradiating a substrate with an energy beam to modify the energy beam, comprising: an energy beam light source for emitting an energy beam; and a stage on which the substrate is mounted. Scanning means for relatively moving the energy beam and the stage, and a beam shield for shielding the energy beam emitted from the energy beam light source,
The beam shield is achieved by an energy beam reformer provided so that a relative positional relationship with the stage is constant.

According to the present invention, since the beam shield is provided so that the relative positional relationship with the stage on which the base is placed is constant, the energy beam and the stage are relatively moved by the scanning means. In the case where the energy beam is gradually shifted and irradiated sequentially on the substrate to modify the substrate, the energy beam is irradiated only on the portion of the substrate to be modified, and therefore, the It is possible to reliably and effectively prevent the portion or the stage from being irradiated with the energy beam, damaging the portion or the stage of the substrate that does not need to be modified, and generating the impurities caused by the damage. .

In a preferred embodiment of the present invention, the energy beam is constituted by a rectangular energy beam.

According to the preferred embodiment of the present invention, since a rectangular energy beam is used, the throughput is improved, and the energy beam is uniformly irradiated in the scanning direction. In this case, it is possible to effectively prevent the crystal grain size from becoming non-uniform.

[0057] In a further preferred aspect of the present invention, the energy beam is constituted by an energy beam selected from the group consisting of a laser beam, an electron beam and an infrared beam.

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

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

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

In a further preferred aspect of the present invention, the laser beam has a pulse width of 20 to 300 ns.
c is set.

[0062] In a further preferred aspect of the present invention, the base is constituted by a thin film formed on a substrate.

In a further preferred embodiment of the present invention, the base is constituted by an amorphous silicon thin film formed on a substrate.

According to a further preferred embodiment of the present invention, the energy beam reforming apparatus is used for annealing TFTs of a flat panel display such as a liquid crystal display panel or an electroluminescence display panel by using an annealing process for an amorphous silicon thin film. It is possible to obtain a TFT with improved characteristics.

In a further preferred aspect of the present invention, the base is constituted by a silicon oxide film formed on the substrate.

In a further preferred embodiment of the present invention, the base is constituted by a polytetrafluoroethylene substrate.

In a further preferred embodiment of the present invention, the substrate is constituted by a glass substrate.

In a further preferred embodiment of the present invention, the substrate is constituted by a plastic substrate.

[0069] In a further preferred aspect of the present invention, the scanning means is configured to be able to move the stage, and the beam shield is interlocked with the stage.
It is configured to be movable.

[0070] In a further preferred aspect of the present invention, the beam shield is connected to the stage.

According to a further preferred embodiment of the present invention, since the beam shield is connected to the stage,
The stage and the beam shield can be easily linked and moved.

[0072] In a further preferred embodiment of the present invention, the energy beam reforming apparatus further includes a chamber, wherein the stage and the beam shield are arranged in the chamber.

[0073] In a further preferred aspect of the present invention, the energy beam reforming apparatus further includes a chamber, wherein the stage is disposed in the chamber, and the beam shield is disposed outside the chamber.

In a further preferred aspect of the present invention, the beam shield is formed of a material that does not cause ablation with respect to the energy beam.

In a further preferred aspect of the present invention, at least the surface of the beam shield is formed of a high melting point metal selected from the group consisting of molybdenum, tantalum and tungsten.

[0076] In still another preferred embodiment of the present invention, at least a surface of the beam shield is formed of ceramic.

In a further preferred embodiment of the present invention, the base is constituted by a thin film formed on a part of the surface of the substrate, and the beam shield exposes only a portion where the thin film is formed. Are located.

According to a further preferred embodiment of the present invention, since the beam shield is disposed so as to expose only the portion where the thin film to be modified is formed, the substrate surface or the stage is irradiated with the energy beam. Therefore, it is possible to prevent the substrate and the stage from being damaged, and to surely prevent the reforming process from being adversely affected by impurities generated by the damage.

[0079] In a further preferred aspect of the present invention, the beam shield is disposed within a depth of focus of the energy beam.

In a further preferred aspect of the present invention, the depth of focus of the energy beam is set to 1 mm or more.

In a further preferred aspect of the present invention, the surface of the beam shield is formed so as to diffusely reflect the energy beam.

According to a further preferred embodiment of the present invention, since the surface of the beam shield is formed so as to diffusely reflect the energy beam, the reflected light of the energy beam from the beam shield is focused on a specific portion. In addition, it is possible to effectively prevent the members of the device from being damaged.

In a further preferred aspect of the present invention, a rectangular opening is formed in the beam shield.

In a further preferred aspect of the present invention, the scanning means is configured to move the stage by a distance smaller than one side of the rectangular energy beam as one unit.

[0085] In a further preferred aspect of the present invention, the scanning means is configured to move the stage by a unit of an integral distance of one side of the rectangular energy beam.

In a further preferred aspect of the present invention, the scanning means is configured to move the stage with a distance different from an integral fraction of one side of the rectangular energy beam as one unit. I have.

[0087] In a further preferred aspect of the present invention, the scanning means is configured to move the stage stepwise in conjunction with the irradiation of the energy beam.

In a further preferred aspect of the present invention, the scanning means is configured to continuously move the stage in conjunction with the irradiation of the energy beam.

In a further preferred embodiment of the present invention, the inside of the chamber is maintained at a reduced pressure.

In a further preferred embodiment of the present invention, the inside of the chamber is filled with an inert gas.

In a further preferred embodiment of the present invention, the inert gas is constituted by a gas selected from the group consisting of nitrogen and an inert gas.

[0092]

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

FIG. 1 is a schematic plan view of a laser annealing apparatus according to a preferred embodiment of the present invention, and FIG.
FIG.

As shown in FIGS. 1 and 2, the annealing apparatus includes a chamber 1 whose inside is maintained at a reduced pressure,
A rectangular XeCl excimer laser beam (resonant wavelength 30
8 nm), a quartz window 4 formed on the upper surface of the chamber 1 and transmitting the laser beam 2, and a glass substrate 6 provided in the chamber 1 and having an amorphous silicon thin film 5 formed thereon. The stage 7 is movable in the horizontal direction (X direction) and the vertical direction (Y direction) in FIG. 1 by a scanning mechanism (not shown), and is integrated with the stage 7 by a coupling mechanism (not shown). A beam shield 8 is provided, the surface of which is covered with molybdenum that does not transmit the XeCl excimer laser beam 2. As shown in FIG. 1, in this embodiment, the amorphous silicon thin film 5 is not formed on the peripheral edge 6 a of the glass substrate 6.

The surface of the beam shield 8 is processed so as to irregularly reflect the XeCl excimer laser beam 2, and the beam shield 8 is arranged within the focal depth of the XeCl excimer laser beam 2. XeCl excimer laser beam 2 emitted from laser light source 3
Has a depth of focus of 1 mm or more. Here, the surface of the beam shield 8 is the XeCl excimer laser beam 2
The surface is processed so as to diffusely reflect the XeCl excimer laser beam 2 reflected by the surface of the beam shield 8 so as to prevent the XeCl excimer laser beam 2 from condensing on a specific region. What is located within the depth of focus of the XeCl excimer laser beam 2 is
This is because XeC does not disturb the intensity distribution of the beam shaped so that uniform irradiation can be performed by the beam homogenizer.
l Incomplete shielding of the excimer laser beam 2
In the outer peripheral portion of the amorphous silicon thin film 5, XeC
This is for surely preventing the irradiation of the excimer laser beam 2 from being incomplete.

[0096] As shown in FIG.
Has a rectangular frame shape, and the laser beam 2 emitted from the laser light source 3 is applied only to the amorphous silicon thin film 5, and the portion of the glass substrate 6 where the amorphous silicon thin film 5 is not formed and the glass substrate 6 of the stage 7 The area around is blocked by the beam shield 8,
It is provided integrally with the stage 7 by a coupling mechanism (not shown) so that the laser beam 2 is not irradiated.

In this embodiment, the stage 7 and the beam shield 8 are moved stepwise by the scanning mechanism in the X and Y directions, that is, in FIGS.
It is configured to be movable in the left-right direction and the up-down direction (front-back direction).

Hereinafter, the method of the annealing process using the laser beam 2 in the present embodiment will be described with reference to FIGS.

As shown in FIG. 3, the amorphous silicon thin film 5 is formed on a glass substrate 6, and the region 5a of the amorphous silicon thin film 5 and the region 12 including the region of the beam shield 8 have a rectangular shape having a resonance wavelength of 308 nm. Xe
A Cl excimer laser beam 2 (not shown) is irradiated. Since the rectangular XeCl excimer laser beam 2 is irradiated, the region 12 also has a rectangular shape. In the present embodiment, a rectangular Xe of 30 mm × 70 mm is used.
Since the Cl excimer laser beam 2 is used, the region 12 also has a rectangular shape of 30 mm × 70 mm. The glass substrate 6 finally becomes a part of the liquid crystal display panel, and the amorphous silicon thin film 5
Annealed by eCl excimer laser beam 2,
It is crystallized to form a TFT (thin film transistor) of a liquid crystal display panel.

In the present embodiment, the irradiated XeCl excimer laser beam 2 has an energy density of 600 mJ / cm 2, and one irradiation time (pulse width) is about 150 nsec. By irradiating each region of the amorphous silicon thin film 5 with such an excimer laser pulse nine times, annealing of each region is completed and amorphous silicon is crystallized.

FIG. 4 is a graph showing the heating characteristics of the amorphous silicon thin film.

As shown in FIG. 4, when the amorphous silicon film is irradiated with an energy beam such as an XeCl excimer laser, the temperature of the amorphous silicon thin film starts to rise, and at about 1100 ° C., the amorphous silicon thin film starts to melt. 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 energy beam is stopped, the cooling of the amorphous silicon thin film is started. If the cooling rate is lower than the predetermined rate, about 14
At 20 ° C., crystalline silicon begins to form. Until the crystallization is completed, the temperature of the amorphous silicon is substantially maintained at about 1420 ° C., and when the amorphous silicon is completely solidified, the temperature is reduced again.

When one area of the XeCl excimer laser beam 2 is irradiated onto the area 12, the edge 6 a of the glass substrate 6 located below the beam shield 8 and the stage 7 are shielded by the beam shield 8. Therefore, even if the region 12 is irradiated with the XeCl excimer laser beam 2, the region 12 other than the XeCl excimer laser beam 2 irradiated onto the region 5a of the amorphous silicon thin film 5 is reflected by the beam shield 8, and 6 and the stage 7 are not reached, and only the region 5a of the amorphous silicon thin film 5 is
Upon receiving the irradiation of the XeCl excimer laser beam 2, it is annealed. Referring to FIG. 2, the beam shield 8 covers the edge 6a of the glass substrate 6 and the stage 7, and prevents the XeCl excimer laser beam 2 from being irradiated to the edge 6a and the stage 7 of the glass substrate 6. Will be easy to understand.

Through the process shown in FIG. 4, the region 5a is irradiated with one shot of the XeCl excimer laser beam 2.
When the crystallization of the amorphous silicon in the region 5c is completed, the stage 7 is moved rightward in FIG. 3 with respect to the XeCl excimer laser beam 2 by a scanning mechanism (not shown). Thereby, the glass substrate 6 and the beam shield 8 are also moved rightward with respect to the XeCl excimer laser beam 2. In this embodiment, as shown in FIGS. 3 and 5, the glass substrate 6 and the beam shield 8 are moved rightward by １ ／ of the width of the region 12 in the left-right direction. A region 13 overlapping the region 12 is irradiated with the XeCl excimer laser beam 2.

XeCl excimer laser beam 2 is applied to region 1
3, the edge 6a of the glass substrate 6 and the portion of the stage 7 located below the beam shield 8
The area 13 is shielded by the beam shield 8.
Is irradiated with the XeCl excimer laser beam 2,
Region 5 of amorphous silicon thin film 5 in region 13
a and the XeCl excimer laser beam 2 applied to the region 5b are reflected by the beam shield 8,
Only the region 5a and the region 5b of the amorphous silicon thin film 5 do not reach the edge 6a of the glass substrate 6 and the portion of the stage 7, and are irradiated with the XeCl excimer laser beam 2 and annealed.

As a result, the region 5a of the amorphous silicon thin film 5 is irradiated with two shots of the XeCl excimer laser beam 2, and the region 5b is irradiated with one shot of the XeCl excimer laser beam 2.

As described above, the regions irradiated with the XeCl excimer laser beam 2 overlap each other by １ ／ of the width in the left-right direction so that the XeCl excimer laser beam 2 is irradiated. The stage 7, that is, the glass substrate 6 and the beam shield 8 are sequentially moved rightward in FIG. 5, and the first column on the surface of the amorphous silicon thin film 5 is scanned by the XeCl excimer laser beam 2.

Thus, when the first row of the surface of the amorphous silicon thin film 5 is scanned by the XeCl excimer laser beam, the stage 7 is moved, and the glass substrate 6 is returned to the original position. As shown in FIG. 6, the glass substrate 6 and the beam shield 8 are moved upward in FIG. The XeCl excimer laser beam 2 is applied to the overlapping second region 14.

The XeCl excimer laser 2 beam is applied to the region 1
4, the edge 6 a of the glass substrate 6 located below the beam shield 8 and the portion of the stage 7
The area 14 is shielded by the beam shield 8.
Is irradiated with the XeCl excimer laser beam 2,
Region 5 of amorphous silicon thin film 5 in region 14
a and the XeCl excimer laser beam 2 applied to the region 5c are reflected by the beam shield 8,
Only the region 5a and the region 5c of the amorphous silicon thin film 5 do not reach the edge 6a of the glass substrate 6 and the stage 7 and are irradiated with the XeCl excimer laser beam 2 to be annealed.

The region 5a and the region 5c of the amorphous silicon thin film 5 are irradiated with one shot of the XeCl excimer laser beam 2, and through the process shown in FIG. When the crystallization of the amorphous silicon in 5c is completed, exactly as in the first column, as shown in FIG.
The stage 7, that is, the glass substrate 6 and the beam shield 8 are moved rightward, and the region 15 is irradiated with the XeCl excimer laser beam following the region 14.
As a result, the region 5a receives irradiation of the XeCl excimer laser beam 2 of 5 shots, and the region 5b receives the XeCl excimer laser beam of 4 shots.
The region 5c is irradiated with the eCl excimer laser beam 2,
Is irradiated with two shots of the XeCl excimer laser beam 2, and the region 5d is irradiated with one shot of the XeCl excimer laser beam 2.

Hereinafter, the XeCl excimer laser beam is
The stage 7, and thus the glass substrate 6 and the beam shield 8, are so arranged that the continuously irradiated areas overlap by 1/3 of the width in the left-right direction and are irradiated with the XeCl excimer laser beam 2. In FIG.
The XeCl excimer laser beam 2 scans the second row of the surface of the amorphous silicon thin film 5 sequentially in the rightward direction.

Thus, when the second column on the surface of the amorphous silicon thin film 5 is scanned by the XeCl excimer laser beam 2, the stage 7, and hence the glass substrate 6, is returned to the original position. As shown, the stage 7, and thus the glass substrate 6 and the beam shield 8, have been moved upward in FIG. 8 by one third of the vertical width of the region 14, and have been moved by only one third of the vertical width. The XeCl excimer laser beam 2 is applied to the region 16 of the third column overlapping the region 14. As a result, the region 5a receives irradiation of the XeCl excimer laser beam 2 of seven shots, the region 5c receives irradiation of the XeCl excimer laser beam 2 of four shots, and the region 5e receives irradiation of the XeCl excimer laser beam 2 of one shot. Will be.

The first surface of the amorphous silicon thin film 5
When the third column on the surface of the amorphous silicon thin film 5 is scanned by the XeCl excimer laser beam 2 in the same manner as the column and the second column, the stage 7, and hence the glass substrate 6, returns to the original position. Then, the fourth column on the surface of the amorphous silicon thin film 5 is scanned by the XeCl excimer laser beam 2.

Similarly, the amorphous silicon thin film 5
Are sequentially scanned by the XeCl excimer laser beam 2, and the entire surface of the amorphous silicon thin film 5 formed on the glass substrate 6 is scanned by the XeCl excimer laser beam 2.

As a result, each region of the amorphous silicon thin film 5 is irradiated with 9 shots of a XeCl excimer laser beam, and the amorphous silicon is crystallized through the process shown in FIG.

According to the present embodiment, each region of the amorphous silicon thin film 5 is different from a region adjacent in the width direction by one width.
The XeCl excimer laser beam 2 is irradiated by overlapping with an XeCl excimer laser beam, and the XeCl excimer laser beam 2 is irradiated and annealed by overlapping with a vertically adjacent region by 1/3 of the width. Therefore, Xe
When performing annealing without overlapping the region irradiated with the Cl excimer laser beam 2,
It is possible to effectively prevent the occurrence of an abnormal crystal which is likely to occur at the boundary between adjacent regions.

Further, according to the present embodiment, the laser light source 3
Since the beam shield 8 is provided to cover the edge 6a of the glass substrate 6 on which the amorphous silicon thin film 5 is not formed and the stage 7, the peripheral edge of the amorphous silicon thin film 5 is irradiated with the XeCl excimer laser beam 2. XeCl excimer laser beam 2
Is not irradiated on the edge 6a of the glass substrate 6 on which the amorphous silicon thin film 5 is not formed or on the stage 7. Therefore, it is possible to reliably prevent the edge 6a and the stage 7 of the glass substrate 6 on which the amorphous silicon thin film 5 is not formed from being damaged due to the irradiation of the undesired XeCl excimer laser beam 2. It is possible to reliably prevent undesirable impurities from being generated and mixed into the amorphous silicon thin film 5 due to such damage to the edge 6a of the glass substrate 6 and the stage 7 where the amorphous silicon thin film 5 is not formed. Will be possible.

FIG. 9 is a schematic vertical sectional view of a laser annealing apparatus according to another preferred embodiment of the present invention.

As shown in FIG. 9, in the laser annealing apparatus according to the present embodiment, the beam shield 9 is provided outside the chamber 1 and the moving mechanism (not shown) for moving the stage 7 is as follows. It is configured to be moved in synchronization with the stage 7 by another moving mechanism (not shown) so that the relative positional relationship with the stage 7 is constant. The beam shield 9 is made of XeC
It is located within the focal depth of the excimer laser beam 2.

According to the present embodiment, the stage 7 on which the glass substrate 6 on which the amorphous silicon thin film 5 is formed is provided inside the chamber 1, whereas the beam shield 9 is provided outside the chamber 1. Because
By irradiating the beam shield 9 with the XeCl excimer laser beam 2, even if some impurities may be scattered, it is possible to reliably prevent the generated impurities from being mixed into the amorphous silicon thin film 5. Become.

Further, according to this embodiment, the beam shield 9 is provided outside the chamber 1 and the XeCl
Irradiation of the excimer laser beam 2 onto the beam shield 9 may generate any impurities, but the generated impurities do not enter the amorphous silicon thin film 5.
May be made of a material that can shield the XeCl excimer laser beam 2, and thus the room for material selection is expanded and the cost can be reduced.

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

For example, in the above embodiment, Xe
30 mm × 70 m as Cl excimer laser beam 2
30mm x 70m
It is not necessary that the beam be a rectangular beam of m, and other shapes such as a circular beam may be used.

Further, in the above embodiment, the XeCl excimer laser beam 2 having an energy density of 600 mJ / cm 2 is used. However, the energy density of the laser beam is not necessarily required to be 600 mJ / cm 2. , Laser beams of various energy densities can be used.

In the above embodiment, XeCl
Excimer laser beam 2 is used, but XeCl
Instead of the excimer laser beam 2, a KrF excimer laser beam (resonant wavelength 248 nm) or an ArF excimer laser beam (resonant wavelength 193 nm) can be used.

Further, in the above embodiment, XeC
Although the excimer laser beam 2 is used, another laser beam can be used instead of the excimer laser beam.

In the above embodiment, XeCl
Although the excimer laser beam 2 is used, an energy beam such as an electron beam or an infrared beam may be used instead of the laser beam.

Further, in the above embodiment, the XeCl excimer laser beam 2 having a pulse width of about 50 nsec.
However, the pulse width of the XeCl excimer laser beam is not necessarily required to be about 50 nsec, and the pulse width of the XeCl excimer laser beam can be selected according to the purpose. For example, the pulse width is preferably set to 20 to 300 nsec. it can.

In the above embodiment, the Xe film is formed on the amorphous silicon thin film 5 formed on the glass substrate 6.
Irradiate with Cl excimer laser beam 2 and anneal,
Although the crystallization is performed, the present invention is not limited to the annealing treatment of the amorphous silicon thin film 5, but may be performed by hydrophilizing the surface of the tetrafluoroethylene plate using an energy beam or on a glass plate using an energy beam. The present invention is also applicable to a process of forming a thin film on silicon, a process of densifying a silicon oxide film formed by plasma CVD using an energy beam, a process of removing hydrogen gas in amorphous silicon using an energy beam, and the like.

Further, in the above embodiment, the glass substrate 6 is used as the substrate.
Not limited to this, a plastic substrate or the like can be used.

In the embodiments shown in FIGS. 1 to 8, the beam shield 8 is connected to the stage 7, but the relative position of the beam shield 8 to the stage 7 is constant. As described above, it is sufficient that the stage 7 is configured to be moved in synchronization with the stage 7, and it is not always necessary that the stage 7 and the beam shield 8 are connected to the stage 7.
It may be configured to be moved.

Further, in the above-described embodiment, the stage 7 is configured to move. However, it is sufficient that the XeCl excimer laser beam 2 and the stage 7 can relatively move. The laser light source 3 may be held so as to be movable.

In the above embodiment, the beam shield 8 whose surface is covered with molybdenum is used. The surface of the beam shield 8 may be covered with a material that does not cause ablation. Further, the entire beam shield 8 does not ablate against a high melting point metal such as molybdenum, tantalum, or tungsten, a ceramic, or a laser beam. It may be formed of a material.

Further, in the above embodiment, the beam shields 8, 9 are arranged within the focal depth of the XeCl excimer laser beam 2, but the beam shields 8, 9
Is within the depth of focus of the XeCl excimer laser beam 2.

In the above embodiment, XeCl
Although the focal depth of the excimer laser beam 2 is set to 1 mm or more, it is not always necessary to set the focal depth of the XeCl excimer laser beam 2 to 1 mm or more.

Further, in the previous embodiment, the surface of the beam shield 8 is formed so as to irregularly reflect the XeCl excimer laser beam 2, but the reflected XeCl
If the excimer laser beam 2 is not focused,
It is not always necessary to provide a configuration for irregular reflection.

In the above embodiment, the inside of the chamber 1 is maintained at a reduced pressure. However, instead of reducing the pressure, the chamber 1 may be filled with an inert gas such as nitrogen or an inert gas.

Further, in the above embodiment, Xe is shifted in the X direction by 1/3 of the width of the irradiation area in the X direction, and Xe
The amorphous silicon thin film 5 is irradiated with a Cl excimer laser beam 2 to scan the amorphous silicon thin film 5 in the X direction.
The amorphous silicon thin film 5 is irradiated with the XeCl excimer laser beam 2 while being shifted, and scanned in the Y direction.
Each region of the amorphous silicon thin film 5 is divided into 9 shots of X.
Annealed by eCl excimer laser beam 2,
Although the amorphous silicon is crystallized, it is not always necessary to scan the XeCl excimer laser beam 2 as described above. The stage 7 may be moved with a predetermined distance smaller than one side of the rectangular XeCl excimer laser beam 2 as one unit. May be moved as a unit, or the stage 7 may be moved as a unit at a predetermined distance different from an integer fraction of one side of the rectangular XeCl excimer laser beam 2.

In the above embodiment, the stage 7 is moved stepwise in synchronization with the irradiation of the XeCl excimer laser beam 2.
It can be moved continuously in conjunction with the irradiation of the Cl excimer laser beam 2.

Further, in the above embodiment, the beam shield 8 is provided along the outer edge of the amorphous silicon thin film 5 formed on the glass substrate 6, but the beam shield 8 is provided along the outer edge of the amorphous silicon thin film 5. It is not necessary to provide the XeCl excimer laser beam 2 to the portion of the amorphous silicon thin film 5 to be annealed if the portion to be annealed is part of the amorphous silicon thin film 5.
The beam shield 8 may be provided so as to cover a portion that does not need to be irradiated with the eCl excimer laser beam 2.

[0141]

According to the present invention, when a predetermined area of a substrate is modified by irradiating an energy beam and irradiating the energy beam while gradually shifting a region of the substrate to be modified. In addition, it is possible to provide an improved energy beam reforming method and an improved energy beam reformer capable of irradiating an energy beam only to a region to be modified.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a laser annealing apparatus according to a preferred embodiment of the present invention.

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

FIG. 3 is a diagram schematically showing a state in which a portion 5a of an amorphous silicon thin film is annealed by irradiating a region 12 with a XeCl excimer laser beam 2. FIG.

FIG. 4 is a graph showing a temperature change on the surface of the amorphous silicon thin film when the amorphous silicon thin film 5 is annealed.

FIG. 5 is a schematic diagram showing a state in which a region 13 is irradiated with an energy beam after a region 12 is irradiated with a XeCl excimer laser beam 2, and a part 5a and 5b of the amorphous silicon thin film is annealed. FIG.

FIG. 6 is a schematic diagram illustrating a state in which a region 13 is irradiated with an XeCl excimer laser beam 2 and then an area 14 is irradiated with an energy beam to anneal portions 5a and 5c of the amorphous silicon thin film. FIG.

FIG. 7 is a schematic view showing a state in which a region 14 is irradiated with an XeCl excimer laser beam 2 and then an energy beam is irradiated on a region 15 to anneal a part 5a to 5d of the amorphous silicon thin film. FIG.

FIG. 8 is a schematic diagram showing a state in which a region 15 is irradiated with an XeCl excimer laser beam 2 and then a region 16 is irradiated with an energy beam to anneal portions 5a to 5c of the amorphous silicon thin film. FIG.

FIG. 9 is a schematic longitudinal sectional view of a laser annealing apparatus according to another preferred embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 chamber 2 XeCl excimer laser beam 3 laser light source 4 quartz window 5 amorphous silicon thin film 6 glass substrate 6a edge of glass substrate 6 stage 8,9 beam shield 12,13,14,15,16 irradiation area

Continued on the front page (72) Inventor Hideharu Nakajima 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masao Jimbo 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation In-house F term (reference) 5F052 AA02 BA04 BB07 CA10 DA02 5F058 BB04 BB07 BF76 BF77 BH17 5F072 YY08

Claims (66)

[Claims] 1. A substrate to be modified is placed on a stage,
An opening is formed corresponding to the portion of the substrate to be modified, and the stage is covered by a beam shield having a constant relative positional relationship with the stage, and energy is applied to the substrate via the opening. An energy beam reforming method characterized in that a beam is shifted in a stepwise manner, sequentially irradiated, and reformed. 2. The energy beam reforming method according to claim 1, wherein the energy beam has a rectangular shape. 3. The energy beam reforming method according to claim 1, wherein the energy beam is constituted by an energy beam selected from the group consisting of a laser beam, an electron beam, and an infrared beam. 4. The energy beam reforming method according to claim 3, wherein the energy beam is constituted by a laser beam. 5. The energy beam reforming method according to claim 4, wherein said laser beam is constituted by an excimer laser beam. 6. The energy according to claim 5, wherein said excimer laser beam comprises an excimer laser beam selected from the group consisting of a XeCl excimer laser beam, a KrF excimer laser beam, and an ArF excimer laser beam. Beam modification method. 7. The pulse width of the laser beam is 20 to 3
The energy beam reforming method according to any one of claims 4 to 6, wherein the energy beam is set to 00 nsec. 8. The apparatus according to claim 1, wherein said base is constituted by a thin film formed on a substrate.
The energy beam reforming method according to any one of the above items. 9. The energy beam reforming method according to claim 8, wherein the thin film is constituted by an amorphous silicon thin film. 10. The method according to claim 8, wherein the thin film is formed of a silicon oxide film. 11. The energy beam reforming method according to claim 1, wherein the substrate is constituted by a polytetrafluoroethylene substrate. 12. The energy beam reforming method according to claim 1, wherein the substrate is formed of a glass substrate. 13. The apparatus according to claim 1, wherein said substrate is constituted by a plastic substrate.
The energy beam reforming method according to any one of the above items. 14. The stage is configured to be movable,
14. The energy beam reforming method according to claim 1, wherein the beam shield is configured to be movable in conjunction with the stage. 15. The beam shield according to claim 1, wherein the beam shield is connected to the stage.
The energy beam reforming method according to any one of the above items. 16. The energy beam reforming method according to claim 1, wherein the stage and the beam shield are disposed in the chamber. 17. The energy beam reforming method according to claim 1, wherein the stage is disposed inside the chamber, and the beam shield is disposed outside the chamber. . 18. The energy beam according to claim 1, wherein at least a surface of the beam shield is formed of a material that does not ablate the energy beam. Reforming method. 19. The energy beam reforming method according to claim 18, wherein at least a surface of the beam shield is formed of a refractory metal selected from the group consisting of molybdenum, tantalum, and tungsten. 20. The energy beam reforming method according to claim 18, wherein at least a surface of the beam shield is formed of ceramic. 21. The base of the beam shield, wherein the base is constituted by a thin film formed on a part of the surface of the substrate, and the opening of the beam shield corresponds to a portion where the thin film is formed. The energy beam reforming method according to any one of claims 8 to 10, 12 to 20, wherein a relative positional relationship with respect to the stage is set. 22. The method according to claim 1, wherein the beam shield is disposed within a depth of focus of the energy beam. 23. The energy beam having a depth of focus of 1
23. The energy beam reforming method according to claim 1, wherein the distance is set to not less than mm. 24. The energy beam reforming method according to claim 1, wherein a surface of the beam shield is formed so as to irregularly reflect the energy beam. 25. The energy beam reforming method according to claim 1, wherein the opening of the beam shield is formed in a rectangular shape. 26. The apparatus according to claim 1, wherein the stage is configured to move by a distance smaller than one side of the rectangular energy beam as one unit. Energy beam modification method. 27. The apparatus according to claim 26, wherein the stage is moved so that a distance of an integral fraction of one side of the rectangular energy beam is set as one unit.
3. The energy beam reforming method according to item 1. 28. The energy beam according to claim 26, wherein the stage is moved so that a distance different from an integer fraction of one side of the rectangular energy beam is set as one unit. Reforming method. 29. The apparatus according to claim 1, wherein the stage is moved stepwise in conjunction with the irradiation of the energy beam.
Item 10. The energy beam reforming method according to Item 1. 30. The apparatus according to claim 1, wherein the stage is configured to be continuously moved in conjunction with the irradiation of the energy beam.
Item 10. The energy beam reforming method according to Item 1. 31. The energy beam reforming method according to claim 16, wherein the inside of the chamber is kept at a reduced pressure. 32. The energy beam reforming method according to claim 16, wherein the inside of the chamber is filled with an inert gas. 33. The energy beam reforming method according to claim 32, wherein the inert gas is constituted by a gas selected from the group consisting of nitrogen and an inert gas. 34. Irradiating the substrate with an energy beam,
An energy beam reforming apparatus for reforming, comprising: an energy beam light source that emits an energy beam; a stage on which the substrate is mounted; a scanning unit that relatively moves the energy beam and the stage; An energy beam reforming device, comprising: a beam shield for shielding the energy beam emitted from a beam light source, wherein the beam shield is provided so that a relative positional relationship with the stage is constant. 35. The energy beam reformer according to claim 34, wherein the energy beam is constituted by a rectangular energy beam. 36. The energy beam reforming apparatus according to claim 34, wherein the energy beam is constituted by an energy beam selected from the group consisting of a laser beam, an electron beam, and an infrared beam. 37. The energy beam according to claim 36, wherein the energy beam is constituted by a laser beam.
The energy beam reforming apparatus according to claim 1. 38. The method according to claim 3, wherein the laser beam is constituted by an excimer laser beam.
8. The energy beam reformer according to 7. 39. The excimer laser beam is XeC
39. The energy beam reforming apparatus according to claim 38, 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. 40. A pulse width of the laser beam is 20 to 40.
The energy beam reformer according to any one of claims 37 to 39, wherein the energy beam reformer is set to 300 nsec. 41. The energy beam reforming apparatus according to claim 34, wherein the substrate is constituted by a thin film formed on the substrate. 42. The energy beam reforming apparatus according to claim 41, wherein the base is constituted by an amorphous silicon thin film formed on the substrate. 43. The energy beam reformer according to claim 41, wherein the base is constituted by a silicon oxide film formed on the substrate. 44. The energy beam reformer according to claim 41, wherein the base is constituted by a polytetrafluoroethylene substrate. 45. The energy beam reformer according to claim 41, wherein the substrate is formed of a glass substrate. 46. The substrate according to claim 41, wherein said substrate is constituted by a plastic substrate.
The energy beam reforming device according to any one of the above. 47. The apparatus according to claim 34, wherein the scanning unit is configured to move the stage, and the beam shield is configured to move in conjunction with the stage. The energy beam reformer according to claim 1 or 2. 48. The apparatus according to claim 34, wherein the beam shield is connected to the stage.
8. The energy beam reforming apparatus according to any one of items 7 to 7. 49. The energy beam reforming apparatus according to claim 34, further comprising a chamber, wherein the stage and the beam shield are arranged in the chamber. The energy beam reforming apparatus according to claim 1. 50. The energy beam reformer further comprises a chamber, wherein the stage is disposed in the chamber, and the beam shield is disposed outside the chamber. The energy beam reforming device according to any one of the above. 51. The energy beam reforming apparatus according to claim 34, wherein the beam shield is formed of a material that does not cause ablation with respect to the energy beam. . 52. The method according to claim 34, wherein at least a surface of the beam shield is formed of a refractory metal selected from the group consisting of molybdenum, tantalum and tungsten. Energy beam reformer. 53. The energy beam reforming apparatus according to claim 34, wherein at least a surface of the beam shield is formed of ceramic. 54. The method according to claim 54, wherein the base is constituted by a thin film formed on a part of the surface of the substrate, and the beam shield is arranged so as to expose only a portion where the thin film is formed. The energy beam reformer according to any one of claims 34 to 53. 55. The energy beam reformer according to claim 34, wherein the beam shield is disposed within a depth of focus of the energy beam. 56. The energy beam having a depth of focus of 1
55 mm or more.
The energy beam reforming apparatus according to claim 1. 57. The energy beam reforming apparatus according to claim 34, wherein a surface of said beam shield is formed so as to diffusely reflect said energy beam. 58. The beam shield according to claim 34, wherein a rectangular opening is formed in the beam shield.
8. The energy beam reforming apparatus according to any one of items 7 to 7. 59. The apparatus according to claim 34, wherein the scanning means is configured to move the stage by a unit smaller than one side of the rectangular energy beam as one unit. The energy beam reformer according to claim 1 or 2. 60. The apparatus according to claim 59, wherein said scanning means is configured to move said stage in units of an integral distance of one side of said rectangular energy beam as one unit. The energy beam reforming apparatus according to claim 1. 61. The apparatus according to claim 61, wherein the scanning means is configured to move the stage with a distance different from an integer fraction of one side of the rectangular energy beam as one unit. 60. The energy beam reformer according to 59. 62. The apparatus according to claim 34, wherein the scanning means is configured to move the stage stepwise in conjunction with the irradiation of the energy beam.
62. The energy beam reformer according to any one of items 61 to 61. 63. The apparatus according to claim 34, wherein the scanning means is configured to move the stage continuously in conjunction with the irradiation of the energy beam.
62. The energy beam reformer according to any one of items 61 to 61. 64. The energy beam reformer according to claim 49, wherein the inside of the chamber is kept at a reduced pressure. 65. The energy beam reformer according to claim 49, wherein the inside of the chamber is filled with an inert gas. 66. The energy beam reformer according to claim 65, wherein the inert gas is constituted by a gas selected from the group consisting of nitrogen and an inert gas.