KR20040099603A - Crystallization Method of Silicon - Google Patents

Abstract

PURPOSE: A method for crystallizing an amorphous silicon is provided to improve characteristics of an element by reducing grain boundary protrusions by using a mask widening a transmissive part and an interrupting part, and secure a margin of a process or equipment. CONSTITUTION: A substrate having an amorphous silicon layer is prepared. A mask is placed, having a transmissive part and an interrupting part having nucleation parts between single crystals laterally growing at both sides of an irradiated part without letting the single crystals meet each other. The amorphous silicon layer is irradiated by complete melting energy by using the mask to form the single crystals and the nucleation parts between the single crystals. The nucleation parts are irradiated by near complete melting energy to form crystals connected to the single crystals with micronuclei in the nucleation parts as seeds.

Description

Crystallization Method of Silicon

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and in particular, a laser irradiation process is performed by using a mask having a larger width of a transmissive portion and a blocking portion to reduce grain boundary protrusion in a grain boundary, thereby improving device performance and improving process or equipment. The present invention relates to a method of crystallizing amorphous silicon capable of securing a margin of.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescents (VFDs) have been developed. Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as a substitute for CRT (Cathode Ray Tube) for mobile image display device because of its excellent image quality, light weight, thinness and low power consumption, and mobile type such as notebook computer monitor. In addition, it is being developed in various ways such as a television for receiving and displaying a broadcast signal, a monitor of a computer.

As described above, although various technical advances have been made in order for the liquid crystal display device to serve as a screen display device in various fields, the task of improving the image quality as the screen display device has many advantages and disadvantages.

Therefore, in order to use a liquid crystal display as a general screen display device in various parts, development of high quality images such as high definition, high brightness, and large area is required while maintaining the characteristics of light weight, thinness, and low power consumption. It can be said.

Such a liquid crystal display may be largely divided into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal panel has a predetermined space and is bonded to the first and second glass substrates. And a liquid crystal layer injected between the first and second glass substrates.

The first glass substrate (TFT array substrate) may include a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing a gate line and a data line, and a plurality of thin films that are switched by signals of the gate line to transfer a signal of the data line to each pixel electrode Transistors are formed.

The second glass substrate (color filter substrate) includes a black matrix layer for blocking light in portions other than the pixel region, an R, G, B color filter layer for expressing color colors, and a common electrode for implementing an image. Is formed.

The first and second glass substrates are bonded to each other by a seal material having a predetermined space by a spacer and having a liquid crystal injection hole, so that the liquid crystal is injected between the two substrates.

In this case, in the liquid crystal injection method, the liquid crystal is injected between the two substrates by osmotic pressure when the liquid crystal injection hole is immersed in the liquid crystal container by maintaining the vacuum state between the two substrates bonded by the reality. When the liquid crystal is injected as described above, the liquid crystal injection hole is sealed with a sealing material.

The driving principle of the general liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the arrangement of molecules can be controlled by artificially applying an electric field to the liquid crystal. Therefore, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal by optical anisotropy, thereby representing image information.

Currently, an active matrix LCD, in which a thin film transistor and pixel electrodes connected to the thin film transistor are arranged in a matrix manner, is attracting the most attention due to its excellent resolution and ability to implement video.

The semiconductor layer of such a thin film transistor has high field effect mobility and low photocurrent, so that polycrystalline silicon is mainly used.

The method of manufacturing the polycrystalline silicon may be divided into a low temperature process and a high temperature process according to the process temperature, among which the high temperature process requires a temperature condition of more than a deformation temperature of the insulating substrate near the process temperature of 1000 ℃, the glass substrate is heat-resistant It is difficult to use expensive quartz substrates with high thermal resistance, and the polycrystalline silicon thin film by this high temperature process has high crystallinity such as high surface roughness and fine grains during film formation. Due to the disadvantage that the device application characteristics are lower than that of silicon, a technique for forming a polycrystalline silicon by crystallizing it using amorphous silicon capable of low temperature deposition has been researched and developed.

The low temperature process may be classified into laser annealing, metal induced crystallization, and the like.

Among them, the laser heat treatment process uses a method of irradiating a pulsed laser beam onto a substrate, and the pulsed laser beam repeats melting and solidification in units of 10 to 10 ² nanoseconds. In this way, since the damage to the lower insulating substrate is minimized, it is most attention in the low temperature crystallization process.

Hereinafter, a crystallization method of silicon according to a conventional laser heat treatment process will be described with reference to the accompanying drawings.

1 is a graph showing the size of particles of amorphous silicon for each laser energy density.

As shown in FIG. 1, crystallization of amorphous silicon may be classified into first, second, and third regions according to the intensity of laser energy.

The first region is a partial melting region, in which laser energy is irradiated to the amorphous silicon layer at an intensity such that only the surface of the amorphous silicon layer is melted, and in the first region, the amorphous silicon layer after such irradiation. Partial melting of the surface of the film is performed, and small crystal particles are formed on the surface of the amorphous silicon layer through a solidification process.

The second region is a near-complete melting region, which is a region in which laser energy is irradiated to the extent that the amorphous silicon layer is almost melted by increasing the laser energy intensity than the first region, and small nuclei remaining after melting It is possible to obtain crystal grains grown as seed and grow in comparison with the first region, but it is difficult to obtain uniform crystal grains. Here, the second region is considerably narrower than the first region.

The third region is a complete melting region, which is a region where laser irradiation is performed to increase the laser energy intensity than the second region to melt all the amorphous silicon layers, and solidification proceeds after all of the amorphous silicon layers are melted. Thus, homogeneous nucleation is possible, and after irradiation, a crystalline silicon layer made of fine homogeneous crystal grains is formed.

In the process of manufacturing polycrystalline silicon, the number of irradiation of the laser beam and the overlapping ratio are controlled to form coarse crystal grains uniformly using the energy density of the second region.

However, it is difficult to provide a reliable thin film transistor element because a plurality of crystal grain boundaries of polycrystalline silicon act as an obstacle to current flow, and an insulating film is destroyed by collision current and deterioration due to collision between electrons in the plurality of crystal grains. In order to solve this problem, SLS (Sequential Lateral Solidification) technology using the fact that the silicon crystal grains grow at the interface between the liquid silicon and the solid silicon in a direction perpendicular to the interface to improve the problem. Technology to form single crystal silicon (Robert S. Sposilli, MA Crowder, and James S. Im, Mat. Res. Soc. Symp. Proc. Vol. 452, 956 to 957, 1997) has been proposed.

In the SLS technology, the amorphous silicon can be crystallized to a single crystal level by appropriately adjusting the laser energy size, the irradiation range and the translation distance of the laser beam, and laterally growing the silicon crystal particles by a predetermined length.

Since the irradiation apparatus used in the SLS process concentrates the beam in a narrow area, it is not possible to simultaneously change the amorphous silicon layer stacked on the large area substrate to polycrystalline. Therefore, after changing the irradiation position of the substrate, the substrate on which the amorphous silicon layer is laminated is mounted on the stage, and then irradiated to a predetermined area, and then irradiated to the entire area of the substrate by moving the substrate to irradiate the next area. To be done.

2 is a schematic view showing a general SLS irradiation apparatus.

As shown in FIG. 2, the SLS irradiation apparatus includes a laser generator 1 for generating a laser beam, a focusing lens 2 for focusing a laser beam emitted through the laser generator 1, and a substrate 10. A mask 3 for dividing and irradiating a laser beam onto the laser beam, and a reduction lens 4 positioned under the mask 3 to reduce the laser beam passing through the mask 3 at a constant rate.

The laser beam generator 1 mainly uses XeCl of 308 nm or KrF of 248 nm as an excimer laser. The laser generator 1 emits an unprocessed laser beam, and the emitted laser beam passes through an attenuator to adjust the energy level and then the focusing lens 2. Will be investigated.

The X-Y stage 5 to which the substrate 10 on which the amorphous silicon layer is deposited is fixed, corresponds to the mask 3.

In this case, in order to crystallize all the regions of the substrate 10, a method of gradually expanding the crystal regions by moving the X-Y stage 5 minutely is used.

Here, the mask 3 is divided into a transmission portion A through which the laser beam passes and a blocking portion B that absorbs the laser beam. The width of the transmissive portion determines the lateral growth length of the grains formed in one exposure.

Hereinafter, a method of crystallizing conventional silicon using the general SLS irradiation apparatus of FIG. 2 will be described.

3 is a cross-sectional view schematically showing a conventional laser heat treatment.

As shown in FIG. 3, after the buffer layer 21 and the amorphous silicon layer 22 are sequentially formed on the substrate 20, the transmission part and the blocking part cross each other sequentially on the substrate 20 on which the amorphous silicon layer 22 is formed. After disposing a mask (not shown), a laser irradiation process is performed on the amorphous silicon layer 22.

The amorphous silicon layer 22 is generally deposited on the substrate 20 by using chemical vapor deposition (CVD), etc., but immediately after deposition, the amorphous silicon layer 22 contains a large amount of hydrogen. Since hydrogen has a characteristic of leaving the thin film by heat, the amorphous silicon layer 22 is first heat-treated to proceed with dehydrogenation. This is because if the hydrogen is not removed in advance, the surface of the crystallized silicon layer becomes very rough and its electrical properties are poor.

FIG. 4 is a plan view illustrating a substrate on which an amorphous silicon layer is formed in which an arbitrary region is crystallized after dehydrogenation.

As shown in FIG. 4, since the beam width of the laser beam and the size of the mask are limited, crystallization using a laser beam cannot be simultaneously performed on the entire area of the substrate 20. Therefore, crystallization is achieved by aligning the mask several times as the size of the substrate becomes larger, and repeating the crystallization process each time.

In this case, if the area crystallized by the reduced area C of the single mask is defined as one block, crystallization in the one block is also performed through a plurality of laser beam irradiation.

FIG. 5 is a view illustrating a state where a portion of an amorphous silicon layer corresponding to a transmission part is crystallized after one irradiation using the SLS irradiation apparatus of FIG. 2.

As shown in FIG. 5, the laser beam is irradiated once through the mask (not shown) positioned on the amorphous silicon layer 22. At this time, the irradiated laser beam passes through the plurality of transmission portions A formed in the mask, and the amorphous silicon layer 22 of the irradiated portion melts and liquefies. In this case, the degree of laser energy uses a high melting region in which the amorphous silicon layer of the irradiated portion is completely melted.

As described above, after the laser beam is irradiated, lateral growth of silicon grain 33 proceeds from the interface 32 of the silicon region, which is completely melted and liquefied, to the irradiation region. Lateral growth of grain occurs in a direction perpendicular to the interface 32.

In the irradiated portion corresponding to the transmissive portion of the amorphous silicon layer 22, if the width of the transmissive portion A of the mask is less than twice the silicon grain growth length, the grains on both sides grown vertically inwards at both interfaces of the silicon region. Is stopped at the mid-point 31 to stop the growth.

In this crystallization process through one-time irradiation, crystallized regions are generated in the number of blocks by the number of the transmission portions A formed in the mask (3 in FIG. 2).

Subsequently, in order to further grow silicon grain, the stage on which the substrate is formed is moved to irradiate a region adjacent to the irradiated portion to form a crystal connected to the crystal formed in the single exposure. Likewise, the irradiated site which is completely melted instantaneously upon irradiation forms crystals from both sides laterally. In general, the length of the crystal growth connected to the adjacent irradiating portion that proceeds through the laser irradiation process is generally grown to a length of 1.5 to 2㎛.

By repeating many of these steps, as shown in FIG. 4, the amorphous silicon layer corresponding to one block (C) can be crystallized.

However, since the transmissive portion A of the mask is relatively smaller in width than the blocking portion B, such a conventional silicon crystallization method is a method in which the stage is crystallized by moving small times several times to crystallize an area of one block. The total time required to move the mask or stage accounts for a large proportion of the total crystallization process time, which leads to a decrease in process yield.

Hereinafter, a conventional mask formed by reducing the width of the blocking part to a level comparable to the transmission part and the crystallization state during laser irradiation will be described.

6 is a plan view showing a mask of another shape used in a conventional SLS irradiation apparatus.

As shown in FIG. 6, the mask 40 used in the conventional SLS equipment is shown by the transmissive part A and the blocking part B formed in the horizontal direction. The width size of the transmission portion (A) and the blocking portion (B) is adjustable. In Fig. 6, the transmissive portion A is shown with a width almost equal to the blocking portion B. In this case, the area that is not exposed in one irradiation is exposed twice in one block in such a manner as to expose an area not exposed in one irradiation. Crystallization is possible.

7A and 7B are plan views illustrating a crystallized state after irradiating an entire area of an amorphous silicon layer using the mask of FIG. 6, and FIG. 8 is a ridge formed when side-grown crystals meet after crystallization of an irradiation site. It is sectional drawing shown.

As shown in FIG. 7A, when the crystallization process is performed through the SLS irradiation apparatus using the mask of FIG. 6, the one-time exposure region of amorphous silicon is referred to as the first determination unit Ia and the second exposure region is the second determination unit. In the case of (Ib), it can be seen that the first crystal part Ia and the second crystal part Ib are formed to cross each other like the pattern shape of the transmissive part A and the blocking part B of the mask. . In this case, the crystals of the adjacent regions of the first crystal part Ia and the second crystal part Ib may have a shape that is connected to each other, and the lateral growth crystal length of the grain ( Lateral growth grain size is determined.

Figure 7b shows the completion of the solidification after irradiation, it can be seen that the side-grown single crystals are formed at the interval indicated by the arrow.

Here, D is a portion where the laterally grown crystals collide with each other when the solidification proceeds after melting, and as shown in the cross-sectional view of FIG. 8, it can be seen that the grown crystals are protruded. Although the thickness of the crystallized silicon layer 82 is actually 500 mW, the height of the raised portion is about 500 mW. When the crystallized silicon 82 is used as the semiconductor layer, the reliability of the thin film transistor may be deteriorated.

The conventional silicon crystallization method as described above has the following problems.

The biggest feature of SLS (Sequential Lateral Solidification) technology that grows crystals laterally is that it uses a mask like a photo process. Therefore, as with the exposure apparatus, the resolution of the optical system and the length of the crystals (SLG: Super Lateral Growth) growing on one side during one exposure and the presence or absence of the nucleation unit formed at the center of the irradiation unit As a result, the pattern of the mask is restricted.

In order to maximize the length of the single crystal growing laterally by laser irradiation, if the width of the permeation part of the mask is formed to be less than twice the crystal length (SLG) formed at one side during irradiation, the crystals formed at both sides in the center of the irradiation site collide with each other. As a result, the ridge is formed, and conversely, when the width of the permeation part of the mask is formed to be greater than twice the length of the crystal formed on one side during irradiation, crystals grown on both sides of the irradiation site do not meet, and a micronucleus forming part is formed in the center. Since the ridge has a problem of deteriorating the reliability of the thin film transistor, it is necessary to remove it. Since the charge mobility is significantly lower than that of other crystal regions at the formed portion, the nucleus forming portion is optionally used as a channel region after the crystallization process. If it becomes a problem.

The present invention has been made to solve the above problems, the laser irradiation process using a mask having a larger width of the transmission portion and the blocking portion to reduce the ridge of the grain boundary to improve the device performance and margin of the process or equipment It is an object of the present invention to provide a method for crystallizing silicon, which can ensure.

1 is a graph showing the size of particles of amorphous silicon according to the laser energy density

2 is a schematic diagram showing a general SLS irradiation apparatus

3 is a cross-sectional view schematically showing a conventional laser heat treatment.

4 is a plan view showing a substrate on which an amorphous silicon layer is formed in which an arbitrary region is crystallized after dehydrogenation;

FIG. 5 is a view illustrating a state in which a portion of an amorphous silicon layer corresponding to a transmission part is crystallized after one irradiation using the SLS irradiation apparatus of FIG. 2.

6 is a plan view showing another type of mask used in a conventional SLS irradiation apparatus;

7A and 7B are plan views illustrating crystallization states after irradiating the entire area of the amorphous silicon layer using the mask of FIG. 6.

8 is a cross-sectional view showing a ridge formed when side-grown crystals meet after crystallization of an irradiation site;

9 is a plan view showing a mask of the SLS irradiation apparatus used in the silicon crystallization method of the present invention.

10A and 10B are plan views showing the silicon crystallization method of the present invention.

11A and 11B are cross-sectional views illustrating a state of amorphous silicon corresponding to the center of the transmission part of FIGS. 10A and 10B.

12A and 12B are plan views showing the silicon crystallization method of the present invention occurring in all regions of the amorphous silicon layer.

* Description of symbols on the main parts of the drawings *

100: mask 110: substrate

111 buffer layer 112 silicon layer

N: Nucleation part S: Interface of both crystals connected to single crystal

The silicon crystallization method of the present invention for achieving the above object comprises the steps of preparing a substrate on which an amorphous silicon layer is formed, and the single crystals do not meet on top of the substrate, side crystals grown on both sides of the irradiation site after irradiation do not meet each other Positioning a mask having a transmissive portion and a blocking portion that may have a nucleation portion therebetween, and irradiating the amorphous silicon layer with complete melting energy using the mask to form single crystals on both sides of the irradiated portion; Forming micronucleus formations between the single crystals and the single crystals; and irradiating the micronucleus formations with near complete melting energy to form crystals connected to the single crystals using the nuclei in the micronucleus formations as seeds. Its features are that it comprises a step.

The irradiated portion on the substrate corresponding to the transmissive portion of the mask is characterized in that it has a width larger than the length of the single crystal growing laterally in amorphous silicon after irradiation once with complete melting energy.

The irradiated portion on the substrate corresponding to the transmissive portion of the mask is characterized in that it has a width of 5% to 20% larger than twice the length of the single crystal grown in the amorphous silicon after one irradiation.

The blocking portion of the mask is characterized in that formed with a width equal to or greater than the transmission gap.

The width of the irradiated portion on the substrate corresponding to the transmissive portion of the mask is characterized in that the 2.6㎛ ~ 3.0㎛.

The complete melt energy is characterized in that the application using the SLS (Sequential Lateral Solidification) equipment.

The complete melting proximity energy is characterized in that the application using the ELA (Excimer Laser Annealing) equipment.

Irradiation of the complete melt proximity energy is characterized in that evenly over the entire area of the substrate.

After the substrate is fixed to the stage, the stage is moved to change the portion irradiated corresponding to the mask.

Hereinafter, with reference to the accompanying drawings will be described in detail the silicon crystallization method of the present invention.

9 is a plan view showing a mask of the SLS irradiation apparatus used in the silicon crystallization method of the present invention.

As shown in FIG. 9, the silicon crystallization method of the present invention uses a mask in which the widths of the transmission part E and the blocking part F are increased in the SLS irradiation apparatus, and the widths of the transmission part E and the blocking part F are increased. The degree is such that the single crystals formed laterally on both sides of the irradiation area in a single irradiation are 5% to 20% larger than the width of the maximum mask that can meet each other.

Since the maximum mask width at which the single crystals formed on the side of the irradiation area can meet is 2.5 μm, the mask 100 of the SLS irradiation apparatus applied in the present invention is 5% to 20% than 2.5 μm based on the substrate on which the amorphous silicon layer is formed. % It has a large irradiation area of 2.6 micrometers-3.0 micrometers. When considering that the reduction lens is positioned under the mask in the SLS irradiation apparatus, the pattern of the mask according to the reduction ratio of the reduction lens is a value obtained by multiplying the reduction ratio by the value of 2.6 μm to 3.0 μm, and the transmission part E and the blocking part. What is necessary is just to form the width of (F).

That is, when a 5-fold reduction lens common to the SLS irradiation apparatus is used, the irradiation region irradiated onto the actual amorphous silicon layer is 1/5 of the width of the transmissive portion E of the mask. Since the thickness is between 3.0 μm and 3.0 μm, the width of the transmissive part and the blocking part of the actual mask can be formed in a size of about 13 μm to 15 μm.

In the present invention, the laser irradiation is performed at the complete melting energy (complete melting energy) density through the transmission portion (E) of the mask 100, the corresponding irradiation site of the amorphous silicon layer exceeds the range where the single crystal can meet, the irradiation Growth occurs so that single crystals growing on both sides of the region do not meet each other, and a nucleation portion is formed in the center of the irradiation region.

When the reduced area corresponding to the substrate of the mask 100 is one block, the mask 100 of the present invention is one block after one irradiation if the blocking part F is relatively larger than the transmission part E. Since a plurality of irradiation steps are performed to irradiate the remaining non-irradiation area other than the irradiation area, the mask 100 of the present invention has twice the width of the blocking part F such that the width of the blocking part F is substantially equal to that of the transmission part E. Irradiation allows crystallization of the reduced area corresponding to the substrate of the mask. In the actual irradiation process, since the side crystal growth of the single crystal is slightly larger than the irradiated region, the blocking portion F may be formed to be equal to or larger than the transmission portion E.

10A and 10B are plan views illustrating the silicon crystallization method of the present invention, and FIGS. 11A and 11B are cross-sectional views illustrating the state of amorphous silicon corresponding to the center of the transmission part of FIGS. 10A and 10B.

As shown in FIG. 10A, when primary laser irradiation is performed using a sequential lateral solidification (SLS) irradiation apparatus equipped with the mask of FIG. 9 with complete melting energy, an amorphous phase on a substrate corresponding to one transmission portion of the mask may be used. The irradiated portion of the silicon layer is melted entirely, the lateral crystals grow from the interface of the liquefied irradiated portion and the amorphous state toward the liquefied irradiated portion, and the single crystals grown on both sides do not meet each other, and the micronucleus forming portion (N) is formed at the center portion of the irradiated portion. ) Is formed.

As shown in FIG. 10B, when the secondary laser is irradiated to the amorphous silicon layer on the substrate at a density of the near complete energy evenly by using an Excimer Laser Annealing (ELA) device (not shown), The single crystals do not melt and maintain their shape, and after the micronuclei are melted in the micronucleus forming unit, crystals grow by using the single crystals formed on the side as seeds.

Therefore, in the state in which mass transport of single crystals grown on both sides does not occur, the complete crystallization energy is applied after complete melting proximity energy is applied, and then the single crystal formed is seeded and the crystals are grown radially. As a result, the protrusion phenomenon at the interface S at which the crystal meets can be drastically reduced.

Referring to the cross-sectional view, as shown in Figure 11a, the silicon 112 is crystallized from both sides when the primary laser irradiation at full melt energy using a wide mask of the transmission portion and the blocking portion, the micronucleus formation portion (N) ) Is formed. As described above, the mass crystals of the micronucleus forming portion N do not occur because the single crystals from both sides of the irradiating portion are shortly grown in the center.

As shown in FIG. 11B, when the second laser irradiation is performed evenly over the silicon layer at full melting proximity energy, after the small nuclei of the small nucleus forming portion N are melted, solidification is performed in which crystals connected from both single crystals are formed. do. After the first laser irradiation, mass transport does not occur, and since the crystallization after the complete melting proximity energy is radial, the ridge phenomenon occurring at the interface S where crystals meet at the central portion is drastically reduced.

12A and 12B are plan views showing the silicon crystallization method of the present invention occurring in the entire region of the amorphous silicon layer.

As shown in FIG. 12A, in the first laser irradiation step of irradiating with complete melt energy using the mask of FIG. 9, the stage is moved after the first exposure and the second exposure is performed to expose the entire non-irradiated region on the substrate where the amorphous silicon is formed. Proceed evenly without. As in FIG. 10A, the small nucleus forming portion N is formed at a site where side-grown single crystals do not meet.

As shown in FIG. 12B, when the secondary laser energy irradiation process is performed at full melting proximity energy without spreading the mask in the ELA equipment and is evenly applied to the entire region where the amorphous silicon is formed in the form of a linear beam, the small nucleus forming portion N The micronuclei of the corresponding site are grown by melting the single crystals formed after melting as seeds. As in FIG. 10B, the ridge phenomenon rapidly decreases at the interface S to exhibit a gentle state.

In the method of crystallizing silicon in the present invention, SLS (Sequential Lateral Solidification) technology is performed, and the width of the permeation part and the blocking part of the SLS irradiation apparatus is manufactured with a margin of 5 to 20%, and laser irradiation is performed.

Therefore, two regions that are laterally grown (lateral growth) do not meet, and a small nucleation region having a small grain is formed between spontaneous nucleation therebetween. Subsequently, when the nucleation region is irradiated with energy of a near complete melting region using a conventional Excimer Laser Annealing (ELA) device, the nucleation region grows laterally. This can lead to a drastic reduction of the grain boundary ridges. At the same time, defect curing within the grains may be achieved when irradiated with the complete melting proximity energy, and the margins may be secured in terms of an optical system or a process by forming a width of a transmissive part and a blocking part of the mask.

The silicon crystallization method of the present invention as described above has the following effects.

First, the permeation of the boundary is reduced by growing the width of the permeation and blocking portions of the mask more than twice the length of grain grown on one side in one irradiation. Therefore, device characteristics are improved in the construction of a thin film transistor using silicon crystallized in this manner.

Second, after performing the first laser irradiation with the full melting energy, the second laser irradiation with the complete melting proximity energy reduces defects due to the curing effect inside the grain.

Third, when forming the same grain size, the width of the permeation part and the blocking part of the mask is increased to reduce the number of shots.

Fourth, the width of the transmissive part and the blocking part of the mask is increased so that a high resolution optical system is not required.

Fifth, the process margin can be increased by the aforementioned effects.

Claims (9)

Preparing a substrate on which an amorphous silicon layer is formed; Placing a mask on the substrate having transmissive portions and blocking portions that do not meet single crystals laterally growing on both sides of the irradiated portion after irradiation and may have nucleation portions between the single crystals; Irradiating the amorphous silicon layer with a complete melting energy using the mask to form micronucleus formations between the single crystals on both sides of the irradiation site and the single crystals; Irradiating the small nucleus forming part with near complete melting energy to form crystals connected to the single crystals using the small nucleus in the small nucleus forming part as a seed. The method of claim 1, The irradiation part on the substrate corresponding to the transmission part of the mask has a width larger than the length of the single crystal growing laterally from amorphous silicon after irradiation once with complete melting energy. The method of claim 2, The irradiated portion on the substrate corresponding to the transmissive portion of the mask has a width of 5% to 20% greater than twice the length of the single crystal grown in the amorphous silicon after one irradiation. The method of claim 1, And the blocking portion of the mask is formed to have the same or larger width than the gap between the transmission portions. The method of claim 3, wherein The silicon crystallization method, characterized in that the width of the irradiated portion on the substrate corresponding to the transmission portion of the mask is 2.6㎛ ~ 3.0㎛. The method of claim 1, The complete melt energy is silicon crystallization method characterized in that the application using a SLS (Sequential Lateral Solidification) equipment. The method of claim 1, The complete melting proximity energy is silicon crystallization method characterized in that the application using the ELA (Excimer Laser Annealing) equipment. The method of claim 1, And irradiating the complete melting proximity energy evenly over the entire region of the substrate. The method of claim 1, And fixing the substrate to the stage, and then moving the stage to vary the irradiated portion corresponding to the mask.