WO2019054723A1

WO2019054723A1 - Laser crystallization apparatus and method therefor

Info

Publication number: WO2019054723A1
Application number: PCT/KR2018/010620
Authority: WO
Inventors: 정병호; 강민진
Original assignee: 고려대학교 세종산학협력단
Priority date: 2017-09-14
Filing date: 2018-09-11
Publication date: 2019-03-21
Also published as: KR101963510B1; KR20190030462A

Abstract

A laser crystallization apparatus is provided. The laser crystallization apparatus comprises: a solid laser light source for emitting a solid laser; a split module for separating the solid laser into a first crystallization layer and a second crystallization laser; a time delay module for emitting the second crystallization laser a predetermined amount of time after the first crystallization laser; and a polarization state control module provided on the laser emission path of the first crystallization layer and/or the second crystallization layer, and controlling the polarization state of the crystallization laser, wherein the first crystallization laser has a higher intensity than the second crystallization laser and can be provided to an object, to be crystallized, a predetermined amount of time before the second crystallization laser.

Description

Laser crystallization apparatus and method thereof

The present invention relates to a laser crystallization apparatus and a method thereof, and more particularly to a laser crystallization apparatus and a method thereof which provide re-crystallization through a double pulse laser.

In general, amorphous silicon (a-Si) has a disadvantage in that the mobility and the aperture ratio of electrons, which are charge carriers, are low and are not compatible with the CMOS process. On the other hand, in a poly-Si thin film device, a driving circuit necessary for writing an image signal to a pixel, which was impossible in an amorphous silicon thin film transistor (a-Si TFT), is formed on a substrate like a pixel TFT- It is possible. Therefore, in the polycrystalline silicon thin film element, the connection between the plurality of terminals and the driver IC becomes unnecessary, so that the productivity and reliability can be improved and the thickness of the panel can be reduced.

As a method for manufacturing such a polycrystalline silicon thin film transistor, there are a method of manufacturing at a high temperature condition and a method of manufacturing at a low temperature condition. In order to form the polycrystalline silicon thin film transistor at a high temperature, expensive materials such as quartz should be used as a substrate. I do not. Therefore, research on a method for mass-producing an amorphous silicon thin film into polycrystalline silicon under low temperature conditions has been actively conducted. Examples of the method for forming the low temperature polycrystalline silicon include solid phase crystallization (SPC), metal induced crystallization (MIC), metal induced lateral crystallization (MILC), excimer And excimer laser annealing (ELA).

For example, Korean Patent Laid-Open No. 10-2009-0105751 (Application No. 10-2008-0031386, Applicant: Samsung Mobile Display Co., Ltd.) discloses a plasma display apparatus including a chamber accommodating a substrate having a silicon layer formed on a surface thereof, A laser beam irradiating portion for irradiating a laser beam to the silicon layer; and a control portion for controlling the concentration of oxygen gas contained in the mixed gas, which is electrically connected to the gas supplying portion, A laser crystallization apparatus and a laser crystallization method including a control section for applying a signal are disclosed. In addition, various techniques related to the laser crystallization method are being developed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser crystallization apparatus and method for controlling a cooling rate of a crystallization target.

Another technical problem to be solved by the present invention is to provide a laser crystallization apparatus and method in which grain characteristics of a crystallization target are improved.

It is another object of the present invention to provide a laser crystallization apparatus and a laser crystallization method in which crystallization degree of a crystallization target is improved.

Another technical problem to be solved by the present invention is to provide an apparatus and a method for laser crystallization in which the mobility of charges in a crystallization target is improved.

The technical problem to be solved by the present invention is not limited to the above.

According to an aspect of the present invention, there is provided a laser crystallization apparatus.

According to one embodiment, the laser crystallization apparatus includes a solid laser light source for emitting a solid laser, a split module for separating the solid laser into a first crystallization laser and a second crystallization laser, And a polarization state control module provided in at least one laser emission path of the first crystallization laser and the second crystallization laser for controlling the polarization state of the crystallization laser, The first crystallization laser has a stronger intensity than the second crystallization laser and can be provided to the crystallization target object earlier than the second crystallization laser by the predetermined time.

According to one embodiment, the polarization state control module includes a phase delay plate, and in accordance with the rotation of the phase delay plate, a polarization state of at least one of the first crystallization laser and the second crystallization laser, Can be controlled.

According to one embodiment, the polarization state control module includes a first polarization state control module and a second polarization state control module, and the first polarization state control module is provided in an emission path of the first crystallization laser, 1 crystallization laser, and the second polarization state control module is provided in an emission path of the second crystallization laser to control the polarization state of the second crystallization laser.

According to one embodiment, the phase delay plate includes a first phase delay plate and a second phase delay plate, and the first and second phase delay plates are included in the first and second polarization state control modules, respectively, And the polarization states of the first crystallization laser and the second crystallization laser can be controlled in accordance with the rotation of the first and second phase delay plates, respectively.

According to an embodiment, the laser crystallization apparatus may further include a control unit, and the control unit may control the rotation of the first phase delay plate or the second phase retardation plate along the longitudinal direction of the crystallization target .

According to one embodiment, the object to be crystallized is composed of channels, and the channels of the object to be crystallized are formed by a first channel extending in the first longitudinal direction and a second channel extending by a predetermined angle in the first longitudinal direction The control unit controls the second phase delay plate when the predetermined angle is less than 45 degrees and controls the first phase delay plate when the predetermined angle is more than 45 degrees.

According to one embodiment, according to at least one phase delay plate control of the first and second phase delay plates of the control unit, the re-crystallization directions of the first channel and the second channel may be equal to each other.

According to one embodiment, the intensity of the first crystallization laser is greater than 225 mJ / cm ² and less than 270 mJ / cm ² , the intensity of the second crystallization laser is 10 to 50% of the intensity of the first crystallization laser, The first crystallization laser may be provided 30 ns to 80 ns earlier than the second crystallization laser.

According to one embodiment, the second crystallization laser may be provided while the crystallization target liquefied by the first crystallization laser is cooled.

According to one embodiment, the laser crystallization apparatus includes a solid laser light source for emitting a solid laser, and a split module for separating the solid laser into a first crystallization laser and a second crystallization laser, Wherein the first crystallization laser has a stronger intensity than the second crystallization laser and is provided to the crystallization target object at a predetermined time earlier than the second crystallization laser, 1 crystallization laser may be greater than 225 mJ / cm < ² > and less than 270 mJ / cm < ² >.

In order to solve the above technical problem, the present invention provides a laser crystallization method.

According to one embodiment, the laser crystallization method includes: a step of emitting a solid laser from a solid laser light source; a step of separating the emitted solid laser into a first crystallization laser and a second crystallization laser; And a second irradiating step of irradiating the crystallization target body with the second crystallization laser after a predetermined period of time after the first irradiating step, wherein the first crystallization laser and the second crystallization laser At least one of the second crystallization lasers may be one in which the polarization state is controlled.

According to one embodiment, the first irradiation step includes a first polarization state control step of controlling a polarization state of the first crystallization laser, and the second irradiation step is a step of irradiating the second crystallization laser with a polarization state of the second crystallization laser, And a second polarization state control step of controlling the second polarization state.

According to one embodiment, the first polarization state control step includes the step of rotating the first phase delay plate to control the polarization state of the first crystallization laser, and the second polarization state control step includes: And controlling the polarization state of the second crystallization laser by rotating the phase delay plate.

According to one embodiment, in the case where the channels of the crystallization object are composed of a first channel extending in the first longitudinal direction and a second channel extending by a predetermined angle in the first longitudinal direction, Wherein the controlling step includes controlling the polarization state of the first crystallization laser by controlling the first phase delay plate when the predetermined angle is more than 45 degrees, And controlling the polarization state of the second crystallization laser by controlling the second phase delay plate when the angle is less than 45 degrees.

According to one embodiment, in the laser crystallization method, the phase-retardation plate control of at least one of the first and second phase delay plates may control the re-crystallization directions of the first channel and the second channel to be equal to each other have.

A laser crystallization apparatus according to an embodiment of the present invention includes a solid laser light source for emitting a solid laser, a split module for separating the solid laser into a first crystallization laser and a second crystallization laser, The first crystallization laser has a stronger intensity than the second crystallization laser, and can be provided to the crystallization target object at a predetermined time earlier than the second crystallization laser. As a result, the cooling rate of the crystallization target is reduced, and the degree of crystallization can be improved.

The laser crystallization apparatus according to the embodiment may include a polarization state control module provided in at least one laser emission path of the first and second crystallization lasers to control the polarization state of the crystallization laser. Thus, the polarization states of the first and second crystallization lasers are controlled, and the crystallization target can have excellent grain characteristics.

The laser crystallization apparatus according to the embodiment may further include the control unit for controlling rotation of one of the first and second phase delay plates included in the first and second polarization state control modules . Accordingly, when the crystallization target is composed of a plurality of channels having different lengths, the re-crystallization directions of the plurality of channels become equal to each other, and mobility of charges in the crystallization target can be improved.

1 is a view showing a laser crystallization apparatus according to a first embodiment of the present invention.

2 is a conceptual diagram illustrating an excimer laser and a solid laser used in a laser crystallization apparatus.

3 is a conceptual diagram for explaining the first and second crystallization lasers of the laser crystallization apparatus according to the first embodiment of the present invention.

4 is a view showing a laser crystallization apparatus according to a second embodiment of the present invention.

5 is a view illustrating first and second polarization state control modules included in the laser crystallization apparatus according to the second embodiment of the present invention.

6 is a view showing channels of an object crystallized by a laser crystallization apparatus according to a second embodiment of the present invention.

7 is a view showing channels of a target object crystallized by a laser crystallization apparatus according to a second embodiment of the present invention.

8 is a flowchart illustrating a laser crystallization method according to an embodiment of the present invention.

9 is a diagram showing a simulation result of a laser crystallization apparatus according to Comparative Example 1. Fig.

10 is a diagram showing the simulation characteristics of the laser crystallization apparatus according to Comparative Example 1 in more detail.

11 is a diagram showing simulation characteristics of the laser crystallization apparatus according to the first embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Further, in the drawings, the thicknesses of the films and regions are exaggerated for an effective explanation of the technical content.

Also, while the terms first, second, third, etc. in the various embodiments of the present disclosure are used to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. Thus, what is referred to as a first component in any one embodiment may be referred to as a second component in another embodiment. Each embodiment described and exemplified herein also includes its complementary embodiment. Also, in this specification, 'and / or' are used to include at least one of the front and rear components.

The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms such as " comprises " or " having " are intended to specify the presence of stated features, integers, Should not be understood to exclude the presence or addition of one or more other elements, elements, or combinations thereof. Also, in this specification, the term " connection " is used to include both indirectly connecting and directly connecting a plurality of components.

In the present specification, the " crystallinity " is used to indicate the ratio of amorphous silicon in the crystallization target.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a conceptual diagram illustrating an excimer laser and a solid-state laser used in a laser crystallization apparatus, and FIG. 3 is a cross-sectional view of a laser crystallization apparatus according to a first embodiment of the present invention Fig. 2 is a conceptual diagram illustrating first and second crystallization lasers of the laser crystallization apparatus according to the first embodiment.

Referring to FIG. 1, the laser crystallization apparatus according to the first embodiment includes at least one of a solid laser light source 100, a split module 200, a reflection mirror M, and a time delay module 300 Lt; / RTI >

The solid laser light source 100 can generate and emit a solid laser (L _o ) required for laser crystallization. For example, the solid-state laser (L _O) is Nd: YAG may be formed. The wavelength and type of the laser generated by the solid laser light source 100 are merely examples, and it is of course possible to generate and emit laser of different wavelengths and types. The solid laser (L ₀ ) emitted from the solid laser light source 100 may be provided to the split module 200.

Unlike the laser crystallization apparatus according to the first embodiment described above, in the case of a laser crystallization apparatus using an excimer laser, there is a problem in that the productivity is lowered due to the slow speed, and the maintenance cost is high.

However, as in the laser crystallization apparatus according to the first embodiment, in the case of a laser crystallization apparatus using a solid laser, stable and high output capability can be achieved, resulting in cost reduction and improved productivity. However, referring to FIG. 2, since the emission time of the solid state laser (see FIG. 2 (b)) is extremely shorter than that of the excimer laser (see FIG. 2 (a)), . Thus, embodiments of the present invention can solve the problem of rapidly cooling molten silicon while implementing crystallization through a solid-state laser.

1, the split module 200 receives the solid laser L _o from the solid laser light source 100 and generates the _first and second crystallization lasers L ₁ and L 2 ₂ ).

The first crystallization laser L ₁ and the second crystallization laser L ₂ are provided in the crystallization target SUB to crystallize the crystallization target. At this time, the first crystallization laser (L ₁ ) may be provided a predetermined time earlier than the second crystallization laser (L ₂ ) in order to improve the degree of crystallization of the crystallization target (SUB). For example, the first crystallization laser L ₁ may be provided 30 ns to 80 ns, preferably 60 ns earlier than the second crystallization laser L ₂ .

More specifically, the first crystallization laser L ₁ may be emitted from the split module 200 and directly provided to the crystallization target SUB. On the other hand, the second crystallization laser L ₂ may be provided to the crystallization target SUB through the reflection mirror M and the time delay module 300.

The reflection mirror M may change the traveling direction of the second crystallization laser L ₂ emitted from the split module 200 and provide the same to the time delay module 300.

Referring to FIG. 3, the time delay module 300 may output the second crystallization laser L ₂ later than the first crystallization laser L ₁ by a predetermined time. Accordingly, the second crystallization laser L ₂ may be provided to the crystallization target SUB a predetermined time later than the first crystallization laser L ₁ . For example, the first crystallization laser L ₁ may be provided 30 ns to 80 ns, preferably 60 ns earlier than the second crystallization laser L ₂ . Alternatively, when the first crystallization laser L ₁ is provided to the crystallization target SUB after a time of less than 30 ns or more than 80 ns longer than the second crystallization laser L ₂ , The cooling rate is not easily controlled and the crystallinity may be lowered.

The intensity of the first crystallization laser (L ₁ ) can be controlled more strongly than the intensity of the second crystallization laser (L ₂ ) in order to improve the degree of crystallization of the crystallization target (SUB). For example, the intensity of the first crystallization laser (L ₁ ) can be controlled to an energy range of more than 225 mJ / cm ² and less than 270 mJ / cm ² . For example, the intensity of the second crystallization laser (L ₂ ) may be 10 to 50% of the intensity of the first crystallization laser (L ₁ ). Alternatively, the crystallization degree of the crystallization target SUB may be lowered in an energy range in which the intensity of the first crystallization laser L ₁ is 225 mJ / cm ² or less or 270 mJ / cm ² or more. For example, the time delay module 300 may make the intensity of the second crystallization laser L ₂ weaker than the first crystallization laser L ₁ through the attenuator.

According to one embodiment, the second crystallization laser L ₂ may be provided while the crystallization target SUB liquefied by the first crystallization laser L ₁ is cooled. In other words, the crystallization target SUB may be melted as the first crystallization laser L ₁ is provided, and then cooled and recrystallized. At this time, the second crystallization laser L ₂ is provided a predetermined time later than the first crystallization laser L ₁ , so that the crystallization target SUB can be provided during cooling.

According to one embodiment, the crystallization target SUB may be disposed on the stage ST. The stager ST can be controlled to move in a specific direction. It can be understood that the crystallization target SUB is a silicon channel layer requiring crystallization. In this case, the first and second crystallization lasers L ₁ and L ₂ are inclined at a predetermined angle?, For example, 5 to 15 degrees, preferably 10 degrees, to the normal line of the crystallization target SUB So that the silicon channel layer can be crystallized. At this time, as the stage ST moves in one direction, the crystallization process can be performed gradually.

Unlike the laser crystallization apparatus according to the first embodiment, when the solid laser L _o is provided only once on the crystallization target SUB, the melted crystallization target SUB is rapidly cooled, There may be a problem. That is, when the crystallization target SUB is rapidly cooled, amorphous silicon (a-Si) may be formed in the crystallization target SUB.

However, alternatively, a laser crystallization apparatus according to the first embodiment has a low intensity than the intensity of the first crystallization laser (L ₁₎ and the first crystallization laser (L ₁₎ on the crystallization object (SUB) As the second crystallization laser L ₂ is provided at intervals of the predetermined time, the cooling rate of the crystallization target SUB is lowered and the degree of crystallization can be improved.

More specifically, when the first crystallization laser L ₁ is provided on the crystallization target SUB, the crystallization target SUB is melted and gradually cooled over time. At this time, when providing the second crystallization lasers (L ₂₎ has a weaker strength than the strength of the first crystallization laser (L ₁₎ on the crystallization object (SUB) which is cooled, the cooling of the crystallization object (SUB) It can slow down and keep the melting state longer. Thus, the degree of crystallization of the crystallization target SUB can be improved.

In the laser crystallization process, when the crystallization target SUB is composed of a plurality of channels, controlling the all of the plurality of channels to be re-crystallized in the same direction corresponds to important design requirements for improving the mobility of charges do.

Accordingly, the laser crystallization apparatus according to the second embodiment of the present invention controls the polarization states of the _first and second crystallization lasers L ₁ and L ₂ so that the plurality of channels are all aligned in the same direction The polarization state control module and the control unit in the laser crystallization apparatus according to the first embodiment. Hereinafter, a laser crystallization apparatus according to a second embodiment of the present invention will be described with reference to FIGS.

Referring to FIG. 4, the laser crystallization apparatus according to the second embodiment includes a solid laser light source 100, a split module 200, a reflection mirror M, a time delay module 300, a polarization state control module 400 ), And a control unit 500, as shown in FIG.

The solid laser light source 100 and the split module 200 may be the same as the solid laser light source 100 and the split module 200 of the laser crystallization apparatus according to Embodiment 1 described with reference to FIG. . That is, the solid laser L _o emitted from the solid laser light source 100 is provided to the split module 200, and the split module 200 splits the solid laser L _o into a first crystallization laser L ₁ ) and a second crystallization laser (L ₂ ).

The reflection mirror M and the time delay module 300 may be the same as the reflection mirror M and the time delay module 300 of the laser crystallization apparatus according to the first embodiment described with reference to FIG. Accordingly, the second crystallization laser L ₂ emitted from the split module 200 is provided to the time delay module 300 by changing the traveling direction by the reflection mirror M, (L ₁ ) by a predetermined time later than the first crystallization laser (L ₁ ).

The polarization state control module 400 may be provided in at least one laser emission path of the first and second crystallization lasers L ₁ and L ₂ to control the polarization state of the crystallization laser.

To this end, the polarization state control module 400 may include a linear polarizer (not shown) and a phase retarder (not shown) disposed after the linear polarizer. The linear polarizer can selectively pass only a specific linearly polarized light component of the laser. As a result, the phase delay effect of the phase delay plate disposed after the linearly polarized plate can be maximized. The phase delay plate can control the polarization states of at least one of the first and second crystallization lasers (L ₁ , L ₂ ) according to the rotation.

According to one embodiment, the polarization state control module 400 may include a first polarization state control module 410 and a second polarization state control module 420. Accordingly, the first polarization control module 410 is located on the outgoing path of the first laser crystallization (L _1), it is possible to control the polarization state of the first laser crystallization (L _1). It said second polarization control module 420 and the second feature on the exit path of the laser crystallization (L _2), it is possible to control the state of polarization of the second laser crystallization (L _2).

Hereinafter, the polarization state control module 400 and the control unit 500 for controlling the rotation of the phase delay plate will be described in detail with reference to FIGS. 5 to 7. FIG.

Referring to FIG. 5, the first polarization state control module 410 may include a first linear polarization plate 412 and a first phase delay plate 414. The first linear polarizer 412 can selectively pass only a specific linearly polarized light component of the first crystallization laser L ₁ . The polarization state of the passed first crystallization laser (L ₁ ) can be controlled through the rotation of the first phase delay plate (414). The second linear polarizer 422 can selectively pass only a specific linearly polarized light component of the second crystallization laser L ₂ . The polarized state of the second crystallization laser L ₂ passed through the second phase delay plate 424 can be controlled through the rotation of the second phase delay plate 424.

For example, the first phase delay plate 414 is rotated θ 'with respect to the optical axis of the first crystallization laser (L _1), a polarization state of the first crystallization laser (L ₁₎ can be controlled. For example, the second phase delay plate 424 wherein the rotation θ '' with respect to the second optical axis of the crystallization laser (L _2), a polarization state of the second crystallization lasers (L ₂₎ can be controlled .

As the polarization states of the first and second crystallization lasers L ₁ and L ₂ are controlled by the first and second polarization

state control modules

410 and 420, The first and second crystallization lasers (L ₁ , L ₂ ) controlled by the first and second crystallization lasers are provided, and excellent grain characteristics can be obtained.

However, when the crystallization target SUB is composed of a plurality of channels having different longitudinal directions, the first and second crystallization lasers (not shown) in which the polarization state is non-controlled on the crystallization target SUB L ₁ , and L ₂ ), it is not easy for all of the plurality of channels to be recrystallized in a certain direction.

Alternatively, the laser crystallization apparatus according to the second embodiment of the present invention may be provided in the emission path of the first and second crystallization lasers (L ₁ , L ₂ ), and the first and second crystallization lasers (L ₁ , L ₂₎ first and second polarization state control module (410, 420) capable of controlling the polarization state of the may contain. Accordingly, the laser crystallization apparatus according to the second embodiment can recrystallize all of the plurality of channels in a predetermined direction even when the crystallization target SUB is composed of a plurality of channels having different longitudinal directions .

According to one embodiment, the laser crystallization apparatus according to the second embodiment of the present invention includes first and second

phase delay plates

414 and 424 included in the first and second polarization

state control modules

410 and 420 The control unit 500 can selectively control the rotation of the motor.

Hereinafter, in the case where the crystallization target SUB is composed of the first channel 610 extending in the first longitudinal direction d ₁ and the second channel 620 extending in the second longitudinal direction d ₂ , 6 and FIG. 7, the operation of the control unit 500 will be described in more detail. It should be understood that the directions and shapes of the first and second channels 620 included in the crystallization target SUB are merely examples, and may include a plurality of channels having different orientations and shapes.

FIG. 6 is a view showing channels of an object to be crystallized by the laser crystallization apparatus according to the second embodiment of the present invention, and FIG. 7 is a view showing channels of the object crystallized by the laser crystallization apparatus according to the second embodiment of the present invention Fig.

6, the crystallization target SUB includes a first channel 610 extending in a first longitudinal direction d ₁ and a second channel 620a extending in a second longitudinal direction d _{2a, b} , b). According to one embodiment, the second longitudinal direction (d _{2a, b} ) may be a direction extending at a predetermined angle in the first longitudinal direction (d ₁ ). For example, the second longitudinal direction d _{2a, b} may be a direction d _2a extending in an inclined manner by 40 degrees in the first longitudinal direction d ₁ and a direction d _2b extending in an inclined manner by 90 degrees. .

The controller 500 may control the rotation of the first phase delay plate 414 or the second phase delay plate 424 along the longitudinal direction of the crystallization target SUB.

More specifically, when the angle of inclination of the second longitudinal direction (d _2a ) is less than 45 degrees in the first longitudinal direction (d ₁ ), the controller 500 controls the rotation of the second phase delay plate 424 Can be controlled. If the angle of inclination of the second longitudinal direction (d _2a ) is greater than 45 degrees in the first longitudinal direction (d ₁ ), the controller 500 controls the rotation of the first phase delay plate 414 .

7, when the controller 500 controls the rotation of at least one of the first phase delay plate 414 and the second

phase delay plate

424, 610 and the

second channels

620a and 620b may be the same. Accordingly, the mobility of charges in the crystallization target SUB can be improved.

The laser crystallization apparatus according to the second embodiment of the present invention includes the solid laser light source 100 and the solid laser L _o by separating the solid laser light L _o into the first and second crystallization lasers L ₁ and L ₂ The split module 200 and the polarization state control module 400 provided in the laser emission path of at least one of the first and second crystallization lasers L ₁ and L ₂ to control the polarization state of the crystallization laser . Accordingly, the polarization states of the first and second crystallization lasers (L ₁ , L ₂ ) are controlled, so that the crystallization target SUB can have excellent grain characteristics.

In other respects, when the crystallization target channels in different directions are given on the substrate, the polarization state of the crystallization laser can be simply controlled without changing the transport direction of the substrate and the light irradiation direction of the solid laser light source 100, The process convenience can be improved.

The laser crystallization apparatus according to the second embodiment may further include the control unit 500 for controlling the rotation of the phase delay plate of any one of the first and second

phase delay plates

414 and 424 have. Accordingly, when the crystallization target SUB is composed of a plurality of channels having different lengths, the re-crystallization directions of the plurality of channels become equal to each other, and mobility of charges in the crystallization target SUB is Can be improved.

Hereinafter, a laser crystallization method according to an embodiment of the present invention will be described with reference to FIG.

8 is a flowchart illustrating a laser crystallization method according to an embodiment of the present invention. It is needless to say that the laser crystallization method described with reference to FIG. 8 can be implemented by the laser crystallization apparatus described above with reference to FIGS. 1 to 7.

Referring to FIG. 8, a laser crystallization method according to an embodiment of the present invention includes a step of emitting a solid laser (S110), a step of separating the emitted solid laser by a first crystallization laser and a second crystallization laser A first irradiation step (S130) of irradiating the object to be crystallized with the first crystallization laser, a second irradiation step (S140) of irradiating the object to be crystallized for a predetermined time after the first irradiation step, ). Hereinafter, each step will be described.

According to step S110, a solid state laser can be prepared. The solid-state laser may be the same as the solid-state laser of the laser crystallization apparatus described with reference to Figs. 1 to 7. The solid laser may be emitted toward the splitter device 200.

According to step S120, the emitted solid laser can be separated into a first crystallization laser and a second crystallization laser. The intensity of the first crystallization laser and the intensity of the second crystallization laser can be controlled. For example, the intensity of the first crystallization laser can be controlled to an energy range of greater than 225 mJ / cm ² and less than 270 mJ / cm ² . For example, the intensity of the second crystallization laser (L ₂ ) may be 10 to 50% of the intensity of the first crystallization laser (L ₁ ).

According to step S130, the first crystallization laser can be irradiated onto the crystallization target. The first irradiation step (S130) may include a first polarization state control step of controlling the polarization state of the first crystallization laser. The first polarization state control step may include the step of rotating the first phase delay plate to control the polarization state of the first crystallization laser.

That is, before the first crystallization laser is irradiated onto the crystallization target, the polarization state of the first crystallization laser is controlled by the rotation of the first phase retardation plate, and the first crystallization laser, whose polarization state is controlled, It can be irradiated to the object.

According to step S140, after the first irradiation step (S130), the second crystallization laser may be irradiated onto the crystallization target after a predetermined time. For example, after the first irradiation step (S130), the second crystallization laser may be irradiated to the crystallization target at a time of 30 ns to 80 ns, preferably 60 ns.

The second irradiation step (S140) may include a second polarization state control step of controlling the polarization state of the second crystallization laser. The second polarization state control step may include a step of rotating the second phase delay plate to control the polarization state of the second crystallization laser.

That is, before the second crystallization laser is irradiated onto the crystallization target, the polarization state of the second crystallization laser is controlled by the rotation of the second phase delay plate, and the second crystallization laser whose polarization state is controlled, It can be irradiated to the object.

When the crystallization target is irradiated with the first crystallization laser, the crystallization target is melted and gradually cooled over time. At this time, if the second crystallization laser having a lower intensity than that of the first crystallization laser is provided on the object to be crystallized, the cooling rate of the crystallization object is lowered and the melting state can be maintained longer. Thus, the degree of crystallization of the crystallization target can be improved.

According to an embodiment, when the channels of the object to be crystallized are composed of a first channel extending in the first longitudinal direction and a second channel extending by a predetermined angle in the first longitudinal direction, And the second polarization state control step may be selectively performed.

More specifically, the first polarization state control step may control the polarization state of the first crystallization laser by controlling the first phase control plate when the predetermined angle is more than 45 degrees. The second polarization state control step may control the polarization state of the second crystallization laser by controlling the second phase control plate when the predetermined angle is less than 45 degrees.

According to the phase delay plate control of at least one of the first and second phase delay plates, the directions of the first channel and the second channel may be equal to each other.

That is, when the predetermined angle is more than 45 degrees, the polarization state of the first crystallization laser is controlled, and when the predetermined angle is less than 45 degrees, the polarization state of the second crystallization laser is controlled and the crystallization target is irradiated . Accordingly, the directions of the first channel and the second channel of the crystallization target become equal to each other, and the mobility of the charge can be improved.

Hereinafter, simulation results and graphs for confirming the characteristics of the laser crystallization apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 9 to 11. FIG. It is needless to say that the simulation results and graphs below can also be implemented by the laser crystallization apparatus according to the second embodiment of the present invention.

Prior to the description of simulation results and graphs for confirming the characteristics of the laser crystallization apparatus according to the first embodiment, a laser crystallization apparatus according to Comparative Example 1 will be described.

The laser crystallization apparatus according to Comparative Example 1

Wherein a single solid laser is provided to the crystallization object.

The laser crystallization apparatus according to the first embodiment and the laser crystallization apparatus according to the first comparative example are summarized in Table 1 below.

구분division	구성Configuration
실시 예 1Example 1	결정화 대상체에 시간 차를 갖는 두번의 고체 레이저 제공Providing two solid state lasers with time differences to the crystallization target
비교 예 1Comparative Example 1	결정화 대상체에 한번의 고체 레이저 제공One solid laser is provided to the crystallization target

9 is a diagram showing simulation results of the laser crystallization apparatus according to Comparative Example 1. Fig.

9 (a) to 9 (d), a solid state laser having a strength of 210 mJ / cm ² , 225 mJ / cm ² , 250 mJ / cm ² and 270 mJ / cm ² is used according to Comparative Example 1 (Ns) of the objects crystallized by each of the laser crystallization apparatuses were confirmed and represented by computer simulation.

As can be seen in FIG. 9 (a), the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 210 mJ / cm ² was 15,20,32,40,45,50, and 65 ns It can be confirmed that a section that is supercooled does not appear during the passage of time. That is, it can be seen that the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 210 mJ / cm ² is not recrystallized.

As can be seen from FIG. 9 (b), the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 225 mJ / cm ² was 15,20,32,40,45,50, and 65 ns , The supercooled region appears at 32, 40, 45, and 50 ns, respectively. That is, it can be seen that the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 225 mJ / cm ² was cooled from 32 ns and recrystallization was smooth at 75 ns.

As can be seen from FIG. 9 (c), the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 250 mJ / cm ² is 15,20,30,34,40,95, and 124 ns The supercooled sections appear at 34, 40, and 95 ns, respectively. That is, it can be seen that the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 250 mJ / cm ² was cooled from 34 ns and recrystallized at 124 ns. However, as can be seen from part A of FIG. 10 (c), it can be seen that the crystallinity is not good as a-Si is found in the recrystallized object.

As can be seen in FIG. 9 (d), the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 270 mJ / cm ² was 15, 20, 25, 30, 40, 90, and 124 ns The supercooled region appears only at 40 ns. That is, it can be seen that the object crystallized by the laser crystallization apparatus using the solid laser having the intensity of 270 mJ / cm ² has poor grain characteristics of the recrystallized object as the crystallization target is rapidly cooled.

As can be seen from FIG. 9, the laser crystallization apparatus according to the embodiment uses a solid laser having an intensity in an energy range of more than 225 mJ / cm ² and less than 270 mJ / cm ² , It is easy to crystallize.

10 (a) and 10 (b), a laser pulse according to the time during which a solid laser is irradiated is measured and represented in a laser crystallization apparatus in which a single solid laser is irradiated according to the comparative example 1, The surface state according to time (ns) was confirmed by computer simulation.

As can be seen from FIG. 10 (a), the laser crystallization apparatus according to Comparative Example 1 shows that the solid laser has one peak at about 18 ns.

As can be seen from FIG. 10 (b), the object crystallized by the laser crystallization apparatus according to the comparative example 1 has a time lapse of 15, 24, 30, 35, 40, 70, 90, 95 and 122 ns And the supercooled sections were observed at 35, 40, 70, 90, and 95 ns, respectively. That is, it can be seen that the object crystallized by the laser crystallization apparatus irradiated with one solid laser proceeded to cooling from 35 ns and recrystallized at 122 ns. However, as can be seen from part B of FIG. 10 (b), it can be seen that the crystallinity is not good as a-Si is found in the recrystallized object.

11 (a) and 11 (b), laser pulses according to the time during which the solid state laser is irradiated are measured and represented in the laser crystallization apparatus irradiated twice with the solid state laser according to the embodiment, (ns) was confirmed by computer simulation.

As can be seen from FIG. 11 (a), the laser crystallization apparatus according to the above embodiment shows that the solid state laser is irradiated twice at about 20 ns and 80 ns.

As can be seen in FIG. 11 (b), the object crystallized by the laser crystallization apparatus according to the above embodiment has a period of 15, 24, 30, 35, 40, 70, 90, 95 and 143 ns The supercooled sections appeared at 35, 40, 70, and 90 ns. That is, it can be seen that the object crystallized by the laser crystallization apparatus irradiated with a single solid laser was cooled from 35 ns and recrystallized easily at 143 ns.

10 and 11, in the case of recrystallizing a target using a solid state laser, it is more preferable to irradiate twice the solid state laser at intervals of about 30 ns to 80 ns than to irradiate a single solid state laser, It can be seen that an excellent object is formed.

In particular, a first crystallization laser intensity when 225 mJ / cm ² greater than and 270 mJ / cm ² below, with the possibility that the a-Si forming the bar, a first crystallization energy intensity of 225 mJ / cm ² in excess of and 270 mJ / cm < ^{2 &} gt ;, it was confirmed that provision of the second crystallization laser helps smooth recrystallization.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

A solid laser light source for emitting a solid laser;

A split module for separating the solid laser into a first crystallization laser and a second crystallization laser;

A time delay module for outputting the second crystallization laser a predetermined time later than the first crystallization laser; And

And a polarization state control module provided in at least one laser emission path of the first crystallization laser and the second crystallization laser to control a polarization state of the crystallization laser,

Wherein the first crystallization laser has a stronger intensity than the second crystallization laser and is provided to the crystallization target object earlier than the second crystallization laser at the predetermined time.
The method according to claim 1,

Wherein the polarization state control module includes a phase delay plate,

Wherein the polarization state of at least one of the first crystallization laser and the second crystallization laser is controlled in accordance with the rotation of the phase delay plate.
3. The method of claim 2,

Wherein the polarization state control module includes a first polarization state control module and a second polarization state control module,

Wherein the first polarization state control module is provided in an emission path of the first crystallization laser to control a polarization state of the first crystallization laser,

And the second polarization state control module is provided in an emission path of the second crystallization laser to control the polarization state of the second crystallization laser.
The method of claim 3,

Wherein the phase delay plate includes a first phase delay plate and a second phase delay plate,

Wherein the first and second phase delay plates are included in the first and second polarization state control modules, respectively,

And controls the polarization states of the first crystallization laser and the second crystallization laser, respectively, in accordance with the rotation of the first and second phase retardation plates.
The method of claim 3,

And a control unit,

Wherein the control unit controls the rotation of the first phase delay plate or the second phase delay plate along the longitudinal direction of the crystallization object.
6. The method of claim 5,

Wherein the crystallization target comprises channels and the channel of the crystallization target comprises a first channel extending in a first longitudinal direction and a second channel extending by a predetermined angle in the first longitudinal direction,

Wherein the control unit controls the second phase delay plate when the predetermined angle is less than 45 degrees and controls the first phase delay plate when the predetermined angle is more than 45 degrees.
The method according to claim 6,

Wherein the re-crystallization directions of the first channel and the second channel are equal to each other according to phase delay plate control of at least one of the first and second phase delay plates of the control unit.
The method according to claim 1,

The intensity of the first laser crystallization is 225 mJ / cm 2, and more than 270 mJ / cm 2 or less,

The intensity of the second crystallization laser is 10 to 50% of the intensity of the first crystallization laser,

Wherein the first crystallization laser is provided 30 ns to 80 ns earlier than the second crystallization laser.
The method according to claim 1,

Wherein the second crystallization laser is provided while the crystallization target liquefied by the first crystallization laser is cooled.
A step of emitting a solid laser from a solid laser light source;

A separation step of separating the emitted solid laser into a first crystallization laser and a second crystallization laser;

A first irradiation step of irradiating the first crystallization laser to a crystallization target; And

And a second irradiation step of irradiating the crystallization target body with the second crystallization laser after a predetermined time after the first irradiation step,

Wherein the polarization state of at least one of the first crystallization laser and the second crystallization laser is controlled.
11. The method of claim 10,

Wherein the first irradiation step includes a first polarization state control step of controlling a polarization state of the first crystallization laser,

And the second irradiating step includes a second polarization state control step of controlling a polarization state of the second crystallization laser.
12. The method of claim 11,

Wherein the first polarization state control step includes the step of rotating the first phase delay plate to control the polarization state of the first crystallization laser,

And the second polarization state control step includes rotating the second phase retardation plate to control the polarization state of the second crystallization laser.
13. The method of claim 12,

In the case where the channels of the crystallization target are composed of a first channel extending in the first longitudinal direction and a second channel extending by a predetermined angle in the first longitudinal direction,

Wherein the first polarization state control step includes controlling the polarization state of the first crystallization laser by controlling the first phase delay plate when the predetermined angle is greater than 45 degrees,

And the second polarization state control step includes controlling the polarization state of the second crystallization laser by controlling the second phase delay plate when the predetermined angle is less than 45 degrees.
14. The method of claim 13,

Wherein the re-crystallization directions of the first channel and the second channel are equal to each other, according to phase delay plate control of at least one of the first and second phase delay plates.
A solid laser light source for emitting a solid laser;

A split module for separating the solid laser into a first crystallization laser and a second crystallization laser; And

And a time delay module for outputting the second crystallization laser a predetermined time later than the first crystallization laser,

Wherein the first crystallization laser has a stronger intensity than the second crystallization laser and is provided to the crystallization target object at a predetermined time earlier than the second crystallization laser,

Wherein the intensity of the first crystallization laser is greater than 225 mJ / cm < 2 > and less than 270 mJ / cm < 2 >.