KR20070038333A - Device for ctallization silicon - Google Patents

Abstract

A crystallization apparatus is provided that prevents adhesion of external particles on a mask. The crystallization apparatus is located under a laser generating unit for generating a laser beam, an optical system for adjusting and focusing the laser beam emitted through the laser generation unit, a field lens unit for changing a pattern of a laser beam provided from the optical system, and a lower portion of the field lens unit, and a mask A mask stage having a predetermined space for mounting the substrate, preventing adhesion of particles on the mask, a particle blocking portion positioned between the field lens portion and the mask stage, and a substrate stage on which the substrate is loaded or unloaded below the mask stage. do.

Crystallization Device, Mask, Particle Blocking

Description

Crystallization Device {Device for ctallization silicon}

1 is a schematic view showing a crystallization apparatus according to an embodiment of the present invention.

2A and 2B are perspective views illustrating the lower protective window of the field lens unit and the particle blocking unit.

3 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a mask stage in a crystallization apparatus according to an exemplary embodiment of the present invention.

4 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a mask stage in a crystallization apparatus according to another exemplary embodiment of the present invention.

5 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a mask stage in a crystallization apparatus according to another exemplary embodiment of the present invention.

6 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, a mask stage, and a reduction lens unit in a crystallization apparatus according to another embodiment of the present invention.

7 illustrates a mask included in a crystallization apparatus according to an embodiment of the present invention.

8 illustrates a process of crystallizing an amorphous silicon film using a crystallization apparatus according to an embodiment of the present invention.

(Explanation of symbols about main parts of drawing)

1: Crystallization Apparatus 100: Laser Generation Section

200: optical system 300: field lens unit

310: upper protective window 320: lower protective window

326: protrusion 328: cooling gas supply pipe

330: side wall 340: upper field lens

350: lower field lens 400: particle blocking part

410: top cover 416: sliding bar

430: lower cover 500: mask stage movement control unit

600: reduction lens unit 700: mask stage

800: substrate stage

The present invention relates to a crystallization device, and more particularly, to a crystallization device for preventing adhesion of external particles on a mask.

As the information society develops, the demand for display devices is increasing in various forms, and recently, various flat panel display devices such as liquid crystal displays (LCDs) and organic light emitting diodes (OLEDs) have been studied. Is already being used as a display device in many devices. In the display panel of this kind, a display panel includes a plurality of pixels arranged in a matrix consisting of a thin film transistor (TFT) formed of an amorphous silicon film or a polycrystalline silicon film formed on a substrate such as glass. The image is realized by turning on / off by switching the thin film transistor of the pixel.

The amorphous silicon film can be formed at a low temperature to form a thin film, and is mainly used in thin film transistors of flat panel displays using glass having a low melting point as a substrate. However, the amorphous silicon film has difficulty in large area of the liquid crystal display due to problems such as low field effect mobility.

Therefore, there is a demand for the application of a polycrystalline silicon film having high field effect mobility (30 cm 2 / VS), high frequency operating characteristics, and electrical characteristics of low leakage current.

Such a method of forming a polycrystalline silicon film is a method of changing an amorphous silicon film into a polycrystalline silicon film by irradiating a laser to an amorphous silicon film formed on a substrate such as glass. Recently, a sequential lateral solidification (SLS) method has been proposed in which lateral growth of silicon crystals is induced using an energy source as a laser to produce large grains of silicon.

The crystallization apparatus using this method is composed of a laser generating unit, a plurality of optical lenses for focusing the laser beam or changing the pattern of the beam, a mask and a substrate stage for transmitting the laser beam in a predetermined pattern, and the like. The apparatus processes the laser beam generated by the laser generating unit with an appropriate energy size, focuses the laser beam through the mask by a plurality of lenses, and changes the pattern and the like. This laser beam is partially transmitted through the mask and irradiated onto the substrate loaded on the substrate stage. The irradiated laser beam completely melts the amorphous silicon film on the substrate. The silicon crystal grains are grown in a direction perpendicular to the interface between the liquid silicon in the portion irradiated with the laser beam on the substrate and the solid silicon adjacent thereto. Subsequently, the mask is moved by a pitch smaller than the size of the formed crystal grains and irradiated with a laser beam to continuously enlarge the size of the crystal by seeding the previously formed crystal.

Here, in the crystallization apparatus, particles are easily adhered to the mask due to the fact that the mask is exposed to the outside and operated at high heat due to high energy. In particular, when the particles adhere to a portion of the mask through which the laser beam passes, the laser beam may not pass through and may not be irradiated onto the substrate, thereby preventing polycrystalline silicon from being formed. This seriously affects the electrical mobility of a thin film transistor or the like of a flat panel display device.

An object of the present invention is to provide a crystallization apparatus for preventing adhesion of external particles on a mask.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above technical problem, a liquid crystal display device according to an embodiment of the present invention includes a laser generation unit for generating a laser beam, an optical system for adjusting and focusing the laser beam emitted through the laser generation unit, and the provided in the optical system. A field lens unit for changing a pattern of a laser beam, a mask stage positioned below the field lens unit, having a predetermined space for mounting a mask, preventing adhesion of particles on the mask, and preventing the field lens unit and the mask stage Particle blocking between the substrate stage and the substrate stage is loaded or unloaded under the mask stage.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a crystallization apparatus according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

First, a crystallization apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

1 is a schematic view showing a crystallization apparatus according to an embodiment of the present invention, Figures 2a and 2b is a perspective view showing the lower protective window and the particle blocking portion of the field lens portion, Figure 3 is an embodiment of the present invention It is a schematic diagram which shows the coupling relationship of a field lens part, a particle blocking part, and a mask stage among the crystallization apparatuses.

The crystallization apparatus 1 includes a laser generator 100, an attenuator 200, an optical system 300, a reflector RM, a field lens unit 400, a particle blocking unit 500, a mask 20, and a mask stage ( 900, a mask stage movement control unit 600, a reduction lens unit 700, and a substrate stage 800.

The laser generator 100 emits a laser beam from a light source. The light source mainly uses 308 nm XeCl or 248 nm KrF as an excimer laser, and the laser generator 100 emits an unprocessed laser beam.

The attenuator 200 adjusts the laser beam provided from the laser generator 100 to have a predetermined energy.

The optical system 300 focuses the energy of the laser beam uniformly by equalizing the focal length of the laser beam passing through the telephoto lenses 310 and the telephoto lenses 310 to spread the laser beam incident from the attenuator 200. Lenses 320.

The reflector RM reflects the laser beam incident from the optical system 300 at a predetermined angle to change the direction of the laser beam. In the embodiment of FIG. 1, the direction of the laser beam is directed to the field lens unit 400. In the embodiment of FIG. 1, the reflector is positioned between the optical system 300 and the field lens unit 400, but a plurality of reflectors may be used to maximize the space occupied by the crystallization apparatus. Unlike in the position of the laser generator, the attenuator and the optical system can be variously modified depending on the position of the reflector.

The field lens unit 400 may include the upper and lower field lenses 440 and 450, the upper and lower protective windows 410 and 420, and the upper and lower fields positioned above and below the lower field lenses 440 and 450. Sidewalls 430 supporting the lenses 440 and 450 and the upper and lower protective windows 410 and 420 from the side surfaces thereof.

The upper and lower field lenses 440 and 450 suitably change the shape of the laser beam incident from the optical system 300 to the pattern level of the mask 20. When the upper field lens 440 has a horizontal cross section of the laser beam incident from the optical system 300, the lower field lens 450 has a long length of the laser beam such that the width of the laser beam is short. The curvatures of the lenses 440 and 450 may be formed differently to have a shape. In FIG. 1, two field lenses are illustrated, but the present invention is not limited thereto, and the number of field lenses capable of changing the shape of the laser beam is not limited.

The upper and lower protective windows 410 and 420 protect the upper and lower field lenses 440 and 450 so that particles do not adhere to the upper and lower field lenses 440 and 450, and the lower protective window 420 is a plate ( At a predetermined position on 422, a lens 424 is disposed to pass a laser beam incident from the upper and lower field lenses 440 and 450. Also, as shown in FIG. 2A, the protrusion 426 is disposed around the lens 424 at the bottom of the plate 422. The protrusion 426 is a sliding bar 516 correspondingly disposed on the upper cover 510 of the particle blocking part 500 when the mask stage 900 moves in the direction of the arrow by the mask stage movement control unit 600. Is inserted into the serves to determine the moving range of the mask stage 900. In addition, the upper protective window 410 also includes a lens for passing the laser beam incident from the optical system 300 on the plate, like the lower protective window 420.

The mask stage 900 is provided with a predetermined space in which the mask 20 may be disposed, and is positioned below the field lens unit 400. The mask stage 900 may be moved in the direction of the arrow by the mask stage movement control unit 600 to irradiate a laser beam to various patterns formed for each part on the mask 20.

As shown in FIG. 7, the mask 20 is divided into a transmission part 22 through which the laser beam incident from the field lens part 400 passes and a blocking part 24 blocking the laser beam. The mask 20 transmits the laser beam incident from the field lens part 400 in a predetermined pattern by a pattern divided into the transmission part 22 and the blocking part 24. The width of the transmissive portion 22 determines the length of lateral growth of crystal grains formed in one exposure.

The particle blocking part 500 prevents particles from adhering on the mask 20, and is disposed between the lower protection window 420 and the mask stage 900 so that the lower protection window 420 and the mask stage 900 are disposed. It is formed while surrounding the periphery. The particle block 500 includes an upper cover 510 for interviewing a portion of the lower protective window 420, and a side cover 520 for interviewing a side surface of the mask stage 900.

The upper cover 510 is a sliding bar disposed along the long side of the plate 512, the laser beam passing portion 514 and the laser beam passing portion 514, as shown in FIG. 2B. 516;

The laser beam passing part 514 is formed such that a laser beam incident from the field lens part 400 on the plate 512 is incident on the mask 20. The length of one side of the laser beam passing part 514 is preferably larger than the width or diameter of the lens 424 of the lower protective window 420 so that the laser beam incident from the field lens part 400 is not blocked. In addition, the length of the other side of the laser beam passing portion 514 is preferably formed large enough so that the laser beam incident on the mask 20 during the movement of the mask stage 900 is not disturbed.

The sliding bar 516 is disposed on the side of the long side of the laser beam passing part 514, and when the mask stage 900 is moved by the mask stage movement control unit 600, the protrusions disposed in the lower protective window 420 ( 426 is inserted and guided to move in the direction of the arrow. In addition, the sliding bar 516 determines the moving range of the mask stage 900 by allowing it to be caught by the protrusion 426 when the mask stage 900 reaches the maximum distance that the mask stage 900 can move.

The particle blocking part 500 completely surrounds the lower part of the field lens part 400 and the mask stage 900 so that external particles do not adhere to the mask 20 mounted on the mask stage 900. In particular, since the laser beam is irradiated onto the substrate 10 through the transmissive portion 22 on the mask 20, defects can be prevented during the operation of forming polycrystalline silicon.

The reduced lens unit 700 is disposed under the mask stage 900, and reduces the predetermined laser beam pattern incident through the mask 20 to transmit the reduced laser beam pattern on the substrate 10.

The substrate stage 800 is disposed below and at a position corresponding to the reduction lens unit 700, and loads or unloads the substrate 10. The substrate stage 800 may move back, forth, left, and right to crystallize all regions of the substrate 10.

4, a crystallization apparatus according to another embodiment of the present invention will be described.

4 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a mask stage in a crystallization apparatus according to another exemplary embodiment of the present invention.

For convenience of description, members having the same functions as the members shown in the drawings of the embodiments described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and therefore description thereof is omitted. As shown in Fig. 4, the crystallization apparatus of this embodiment has the same structure as the crystallization apparatus of the previous embodiment except for the following.

The lower protective window 420a includes a plate 422, a lens 424 positioned at a predetermined position, a protrusion 426 positioned adjacent to the lens 424 at the bottom of the lower protective window, and a cooling gas supply pipe 428. Include.

The cooling gas supply pipe 428 prevents the mask 20 in the space surrounded by the particle blocking part 500 from being deformed by the laser beam having the high energy. The cooling gas supply pipe 428 is disposed between the plate 422 of the lower protective window 420 and the plate 512 of the upper cover 510 between the lens 424 and the protrusion 426. The cooling gas supply pipe 428 provides gas, for example, nitrogen gas or air, through an external gas supply device (not shown) to the inside of the space surrounded by the particle blocking part 500.

On the other hand, the mask stage 900a includes a plate 910 and an air outlet 920 disposed around the position where the mask 20 on the plate 910 is mounted.

The air outlet 920 is a focal length of the laser beam when the internal beam is heated by the laser beam having a high energy into the space surrounded by the particle blocking unit 500 when the laser beam is incident into the internal air having a different refractive index than the external air To prevent it from changing. The air outlet 920 is formed by passing at least one hole through the plate 910 around the position where the mask 20 is mounted on the plate 910 of the mask stage 900.

5, a crystallization apparatus according to another embodiment of the present invention will be described.

5 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a mask stage in a crystallization apparatus according to another exemplary embodiment of the present invention.

For convenience of description, members having the same functions as the members shown in the drawings of the embodiments described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and therefore description thereof is omitted.

The particle blocking part 500b may include a top cover 510b and a side cover 520 that is in contact with a side surface of the mask stage 900, and the top cover 510b may be formed in a bellows type that may be folded or unfolded. . Here, the bellows type upper cover 510b abuts the side of the lower protective window 420b and the side cover 520, respectively. The direction in which the top cover 510b can be folded or unfolded is the same as the direction in which the mask stage 900 moves.

Referring to FIG. 6, a crystallization apparatus according to another embodiment of the present invention will be described.

6 is a schematic diagram illustrating a coupling relationship between a field lens unit, a particle blocking unit, and a reduction lens unit in a crystallization apparatus according to another embodiment of the present invention.

For convenience of description, members having the same functions as the members shown in the drawings of the embodiments described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and therefore description thereof is omitted.

The particle blocking part 500c includes a top cover 510 and a side cover 520 that is in contact with the side of the mask stage 900, and a bottom cover 530 between the mask stage 900 and the reduction lens part 700. do.

The lower cover 530 is formed while enclosing the space between the mask stage 900 and the reduction lens unit 700, and the lower cover 530 is formed between the mask stage 900 and the reduction lens unit 700. In addition to preventing the particles from adhering to the lens of the reduction lens unit 700 by blocking the inflow, the laser beam is exposed to the outside in the above-mentioned space and the focus of the laser beam irradiated on the substrate is changed due to the turbulence of external air. Prevents losing

Hereinafter, a process of forming a polycrystalline silicon film using the crystallization apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 8.

8 illustrates a process of crystallizing an amorphous silicon film using a crystallization apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the substrate 10 on which the amorphous silicon film 12 is deposited is loaded on the substrate stage 800.

Subsequently, the laser beam generated by the laser generator 100 is on the substrate 10 through the attenuator 200, the optical system 300, the field lens unit 400, the mask 20, and the reduction lens unit 700. Irradiate a laser beam with a constant pattern.

As shown in FIG. 8A, the first irradiated laser beam is divided by a plurality of transmission portions (see 22 in FIG. 7) formed in the mask 20 to partially dissolve and liquefy the amorphous silicon film 12. In this case, the laser energy uses a high energy melting zone (complete melting regime) such that the amorphous silicon film 12 is completely melted.

When the completely melted and liquefied amorphous silicon is irradiated with the laser beam, the lateral growth of the silicon grains 15 proceeds at the interface 14 between the amorphous silicon region and the liquefied silicon region. Lateral growth of silicon grains occurs perpendicular to the interface 14. The grains 15, which started to grow perpendicular to both interfaces 14, collide with each other at the center 16.

Subsequently, after the primary laser beam irradiation, the substrate stage 800 is moved several micrometers equal to or smaller than the lateral growth length of the crystal grains 15, and then the secondary laser beam irradiation is performed again. The part of the silicon that touches the secondary irradiated laser beam is liquefied and then crystallized again. At this time, the silicon crystal grains 15 of the polycrystalline silicon region formed as a result of the primary irradiation act as seeds, and the lateral growth of the crystal grains is formed in the silicon melting region. After the secondary irradiation, the silicon crystals grow laterally in succession to the grains grown by the primary irradiation.

In the embodiments of the present invention, various embodiments are described separately, but a combination of the various embodiments may be made within the range possible.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the crystallization apparatus of the present invention as described above has one or more of the following effects.

First, by arranging particle blocking portions that block the periphery of the mask from the outside, the mask is not exposed to the outside so that external particles do not adhere to the mask. In particular, it is possible to lower the defective rate in forming the polycrystalline silicon film on the substrate by preventing the laser beam from adhering at the portion where the laser beam passes on the mask.

Second, by injecting cooling gas or forming an air outlet inside the particle blocking unit, it is possible to extend the life of the mask or to prevent the change of the irradiation path of the laser beam.

Third, by forming the particle blocking part up to the reduction lens part, the laser beam passing through the mask is not influenced by external airflow, thereby forming a fine polycrystalline silicon film.

Claims (11)

A laser generator for generating a laser beam; An optical system for adjusting and focusing the laser beam emitted through the laser generator; A field lens unit for changing a pattern of the laser beam provided from the optical system; A mask stage positioned below the field lens unit and having a predetermined space for mounting a mask; A particle blocking part preventing adhesion of particles on the mask and positioned between the field lens part and the mask stage; And And a substrate stage on which a substrate is loaded or unloaded under the mask stage. According to claim 1, The field lens unit comprises at least one field lens; And And a protective window under the field lens. The method of claim 2, And an upper cover of the particle blocking portion is in contact with a portion of the bottom surface of the lower protective window. The method of claim 3, wherein The protective window further comprises a projection in a predetermined position on the bottom surface. The method of claim 4, wherein The upper cover further includes a sliding bar in which the protrusion is inserted into an upper surface of the mask stage to move in one direction, and formed in the same direction as the direction of the one side. The method of claim 2, The protective window and the particle blocking portion further comprises a cooling gas supply pipe passing through it. The method of claim 6, And the cooling gas supply pipe introduces nitrogen gas or air onto the mask. According to claim 1, The mask stage further comprises an air outlet around the mounting position of the mask. According to claim 1, The top cover of the particle blocking portion has a bellows type that can be folded or unfolded crystallization apparatus. According to claim 1, And a reduction lens unit for reducing the laser beam transmitted from the mask at a constant ratio between the mask stage and the substrate stage. The method of claim 10, The particle blocking unit further includes a lower cover positioned between the mask stage and the reduction lens unit.

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