KR100719555B1 - TFT and OLED comprising the same TFT and method of crystallizing semiconductor applied to the same TFT - Google Patents

Abstract

The present invention provides a thin film transistor using a thermal barrier layer, an organic light emitting display device including the thin film transistor, and a polycrystalline semiconductor crystallization method.

The thin film transistor includes a substrate, a heat shield layer formed on the substrate, and a polycrystalline semiconductor active layer having source, drain, and channel regions formed on the heat shield layer.

The present invention provides a thin film transistor having a high channel mobility by using a thermal barrier layer in a process of forming a polycrystalline semiconductor by a laser heat treatment method, thereby improving grain growth of the polycrystalline semiconductor, and an organic light emitting display device having excellent characteristics including the thin film transistor. Enables implementation of

Description

Thin film transistor, organic light emitting display device including the thin film transistor, and polycrystalline semiconductor crystallization method for use in the thin film transistor {TFT and OLED comprising the same TFT and method of crystallizing semiconductor applied to the same TFT}

1 is a cross-sectional view briefly showing the movement of the heat of the amorphous silicon layer on the substrate during the conventional laser heat treatment.

2A and 2B are cross-sectional views briefly illustrating the movement of heat of an amorphous silicon layer on a substrate during laser heat treatment according to the first and second embodiments of the present invention.

3A and 3B are cross-sectional views illustrating in detail a cross section of a thin film transistor according to a first and a second embodiment of the present invention.

4 is a cross-sectional view showing a cross section of an OLED including a TFT of the first embodiment of FIG. 3A according to the third embodiment of the present invention.

5A to 5C are cross-sectional views schematically illustrating a crystallization process of a polycrystalline silicon thin film layer used as a semiconductor active layer of the polycrystalline semiconductor TFT of the second embodiment of FIG. 3A.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor, an organic light emitting display device including the transistor, and a polycrystalline semiconductor crystallization method for use in the transistor. The present invention relates to a polycrystalline semiconductor thin film transistor and a polycrystalline semiconductor crystallization method having excellent characteristics of improving crystallization efficiency, that is, grain growth of polycrystalline semiconductors by blocking heat transfer to the substrate.

Generally, among the elements constituting a thin film transistor (TFT), a semiconductor active layer is formed of amorphous silicon containing hydrogen having no periodicity of lattice depending on its crystal state. Or polycrystalline solid (polysilicon) is used.

Amorphous silicon can be deposited at a low temperature to form a thin film, and is mainly used for switching elements of liquid crystal panes using glass having a low melting point as a substrate.

In this case, when the semiconductor active layer of amorphous silicon including hydrogen is used as a switching device, especially when exposed to light, photocurrent is generated by photoelectric conversion, which acts as an off-state leakage current that is fatal to the operation of the switching device. Done.

In addition, even if the semiconductor active layer is not exposed to light, many defects such as dangling bonds, which are characteristic of amorphous silicon, are formed, and the operation characteristics of the device are not smooth due to the flow of electrons. This is not good.

Accordingly, the amorphous silicon thin film has problems of deterioration of electrical characteristics and reliability of the liquid crystal panel driving device and difficulty of large display area.

In general, the commercialization of large area, high-definition and panel image driving circuits, integrated laptop computers, and wall-mounted LCDs has excellent electrical characteristics, such as high field effect mobility and high frequency operation characteristics. Low leakage current pixel driving elements are required.

When the polysilicon layer is used as a semiconductor active layer, fewer defects are generated on the surface, and the operation speed of the thin film transistor is about 100 to 200 times faster than that of the semiconductor active layer of amorphous silicon. Therefore, the thin film transistor using the polysilicon layer as a semiconductor active layer has extremely fast operation characteristics and can operate in conjunction with an external high speed driving integrated circuit, thereby displaying real-time image information such as a large area liquid crystal display device. It becomes a switching element suitable for the apparatus.

The method of manufacturing polysilicon can be divided into low temperature process and high temperature process according to the process temperature. Among the high temperature process, the process temperature is about 1000 ° C, and the temperature condition is higher than the deformation temperature of the insulating substrate, and instead of the glass substrate having low heat resistance It is necessary to use an expensive quartz substrate with high heat resistance, and the polycrystalline silicon thin film by this high temperature process has high surface roughness and low crystallinity such as fine grains during film formation. Since there is a disadvantage in that device application characteristics are poor, a technology 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 these, the laser heat treatment process uses a method of irradiating a pulsed laser beam onto a substrate, and the method is repeated by melting 10 to 10 ² nanoseconds by melting and solidification by a pulsed laser beam. As it proceeds, it has the advantage of minimizing the damage (damage) to the lower insulating substrate has been attracting the most attention in the low temperature crystallization process.

However, even with the above laser heat treatment method, as shown in FIG. 1, a row (shown by three arrows on the drawing) of the laser beam (hatched rectangular portion under the laser device) of the laser device 200 is formed in the amorphous silicon layer 40a. By transferring the buffer layer 20 to the substrate 10 through the buffer layer 20, heat used for crystallization is reduced, thereby reducing the grain growth of the polycrystalline silicon. In particular, when using a metal substrate, heat conduction and absorption may occur due to the characteristics of the metal. And since the heat dissipation is large and the heat transfer to the metal substrate is large, it is difficult to effectively melt the amorphous silicon, which has a problem of lower grain growth.

On the other hand, in the case of using a non-heat-resistant substrate such as glass or plastic material, the main problem is how to prevent deformation of the substrate by the heat transfer during the laser heat treatment process, in order to solve the problem heat absorbing layer or heat dissipation Although it is intended to solve by layer, the heat of the silicon layer is also transferred to the heat absorbing layer or heat dissipating layer, and still have the problem of the above-described grain growth reduction in terms of thermal efficiency.

The present invention has been made to solve the problems of the prior art, an object of the present invention, by forming a heat shielding layer to block the movement of heat beneath the amorphous silicon layer, the amorphous silicon by the laser heat treatment method to polycrystalline silicon During crystallization, the heat of the laser beam is blocked from moving to the substrate, and most of the heat of the laser beam contributes to the melting of the amorphous silicon without moving to the substrate or the like, thereby improving grain growth of the polycrystalline silicon, thereby providing excellent characteristics. To fabricate a semiconductor active layer and to provide a polycrystalline semiconductor thin film transistor and a polycrystalline semiconductor crystallization method including such a semiconductor active layer.

In order to achieve the above object, the present invention provides a thin film transistor including a substrate, a heat shield layer formed on the substrate, and a polycrystalline semiconductor active layer having a source, a drain, and a channel region formed on the heat shield layer.

In order to achieve the above object, the present invention also provides a thin film transistor comprising a substrate, a heat blocking layer formed on the substrate, a polycrystalline semiconductor active layer having a source, a drain and a channel region formed on the heat blocking layer and the thin film. An organic light emitting display (OLED) including an organic light emitting device including a pixel electrode, an organic light emitting layer, and a common electrode formed on a transistor is provided.

On the other hand, the present invention, in order to achieve the above object, the first step of forming a heat shielding layer on the substrate, the second step of forming an amorphous semiconductor thin film layer on the heat shielding layer and the amorphous semiconductor thin film layer using a laser heat treatment method And a third step of crystallizing the polycrystalline semiconductor thin film layer, and blocking heat transfer to the substrate using the heat blocking layer in the laser heat treatment process of the third step.

The heat shield layer should have low thermal conductivity for effective heat shielding which is the object of the present invention. In the meantime, the semiconductor mainly refers to a silicon semiconductor, and will be described below with a silicon semiconductor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2A is a cross-sectional view schematically showing the heat transfer of an amorphous silicon layer on a substrate during laser heat treatment according to the first embodiment in terms of a vertical structure, in which a laser beam (hatched rectangular under the laser device) in the laser device 200 is shown. Unlike in FIG. 1, the heat of the portion is reflected or blocked by the heat shielding layer 30 (heat of the center portion is absorbed into the amorphous silicon layer by the laser beam, and the left and right arrows by the heat blocking layer Reflected or blocked heat), and stays in the amorphous silicon layer 40a and cannot be transferred to the lower buffer layer 20 or the substrate 10.

FIG. 2B is a cross-sectional view schematically illustrating a heat transfer state in the laser heat treatment according to the second embodiment. Unlike FIG. 2A, the heat blocking layer 30 is immediately removed from the buffer layer 20 of FIG. 2A. By forming the thermal barrier layer 30, the thermal barrier layer 30 as shown in FIG. It is a matter of course that the thermal barrier layer should have characteristics as a buffer layer.

3A shows in detail the cross section of the polycrystalline semiconductor TFT according to the first embodiment.

The polycrystalline semiconductor TFT according to the first embodiment is formed on a substrate 10, and the substrate 10 is made of glass, plastic material such as acrylic, polyimide, polycarbonate, polyester, mylar, or stainless steel ( Metal materials such as SUS), aluminum (Al) and titanium (Ti) may be used, and are particularly useful for the purpose of the present invention in the case of metal substrates with high heat conduction, absorption and dissipation.

The buffer layer 20 is formed on the substrate 10 to prevent diffusion of impurity ions, and to act as a buffer for preventing distortion, which may occur due to non-uniform contact between the substrate and the upper layer. This buffer layer may be optional depending on the material of the substrate or the characteristics of the top layer. Although not shown in FIG. 3A, a barrier layer may be formed to prevent penetration of moisture or external air.

A heat blocking layer 30 is formed on the buffer layer 20 to thermally block the substrate 10 from the silicon layer. This heat shield layer 30 blocks the heat transfer from the silicon layer to the substrate when the later-formed amorphous silicon layer is crystallized into a polycrystalline silicon layer through laser heat treatment as described above in FIG. Contribute to the melting of. By enabling the melting at higher and sustained temperatures by the action of this thermal barrier layer, the grain growth of the polycrystalline silicon is improved, thereby increasing the field effect mobility, resulting in high channel mobility. It is possible to manufacture a semiconductor active layer having excellent excitation characteristics.

Factors to be considered for the material of the thermal barrier layer 30 include: i) high melting point, ii) no phase change between room temperature and operating temperature, iii) low thermal conductivity, iv) thermal expansion match with the metallic substrate, v) good adhesion to the metal substrate, and thermal expansion coefficient and thermal conductivity are the most important factors. Because the thermal expansion coefficient of the thermal barrier layer should be similar to the thermal expansion coefficient of the substrate (the metal substrate is used as an example, but other substrates as well) to prevent torsion or separation from the substrate. Low thermal conductivity is required for this purpose.

Currently, the thermal-barrier-coating (TBC) has been researched and developed for many years in the field of engines such as automobiles and aircrafts. To date, the yttria-stabilized zirconia : YSZ) and its compounds are known to be excellent and are commonly used. On the other hand, efforts are underway to find better TBCs based on YSZ, and rare-earth zirconates are attracting attention as promising substitutes for YSZ.

It is of course possible to use the above materials as the thermal barrier layer in the present invention, and other materials that are more effective for thermal barrier between the substrate and the silicon film may be used as the thermal barrier layer in view of the above factors.

The polycrystalline semiconductor TFT includes a semiconductor active layer 40, a gate electrode 70 insulated from the semiconductor active layer 40, and a source and drain electrode 80 in contact with the semiconductor active layer 40.

The semiconductor active layer 40 is formed on the heat shielding layer 30, and is formed by laser heat treatment of amorphous silicon, crystallization into polycrystalline silicon, and activation through implantation of impurity ions as described above. The semiconductor active layer is divided into a source and a drain region, which are portions into which high concentration impurity ions are implanted, and a channel region serving as a channel.

Silicon oxide (SiO ₂ ) on the semiconductor active layer 40 to cover it And / or a gate insulating film 50 made of silicon nitride (SiN _x ) or the like is formed, and MoW, Al, Cr, Al / Cu, Ti are formed at portions corresponding to the channel regions of the semiconductor active layer on the gate insulating film 50. The gate electrode 70 is formed of a conductive metal film such as / Al / Ti. An interlayer insulating film 60 made of silicon oxide and / or silicon nitride is formed on the gate insulating film 50 and the gate electrode 70, and a source / drain electrode formed to be insulated from the gate electrode 70 thereon. 80 is disposed. The source / drain electrodes 80 are made of a conductive metal film such as MoW, Al, Cr, Al / Cu, Ti / Al / Ti, or a conductive material such as a conductive polymer. In addition, the source / drain electrodes 80 are connected to the source / drain regions of the semiconductor active layer 40 through the contact holes 50a, respectively. By forming in this way, the TFT according to the present embodiment is formed.

The structure of such a TFT is not necessarily limited thereto, and of course, TFTs having various structures can be applied to the present invention.

FIG. 3B is a cross-sectional view showing in detail the cross section of the polycrystalline semiconductor TFT according to the second embodiment, and unlike FIG. 3A, there is no buffer layer. In other words, by using the heat shield layer 30 as a buffer layer, one step of the process can be reduced. This heat shield layer 30 should be provided with the characteristics of the buffer as well as the effect of the heat shield, of course. Other parts of FIG. 3B are the same as in FIG. 3A, and thus, further description is omitted.

4 is a cross-sectional view of an organic light emitting display (OLED) including a thin film transistor according to a first embodiment of FIG. 3A according to a third embodiment of the present invention. OLEDs include a plurality of TFTs and organic light emitting devices.

Referring to FIG. 4, the buffer layer 110 is formed on the substrate 100, and the heat blocking layer 120 applied in the first embodiment is formed on the buffer layer 110. The TFTs 11 and 12 and the organic light emitting element 15 described in the first embodiment are formed on the heat shield layer 120. These TFTs 11 and 12 represent the driving TFT 11 and the switching TFT 12 of the selection driving circuit for implementing the pixel of the light emitting element. A large number of TFTs and light emitting devices are required for the implementation of the overall OLED, but for the convenience of description, only one light emitting device and TFTs 11 and 12 for pixel implementation are shown here.

As described above, the substrate 100 may use a glass material, a plastic material, or a metal material. The buffer layer 110 may be selectively formed on the substrate 100 to prevent the diffusion of impurity ions as necessary. The thermal barrier 120 is formed on the buffer layer 110, and the TFTs 11 and 12 are formed on the thermal barrier layer 120. Meanwhile, as described above, the buffer layer 110 may be omitted, and the heat blocking layer 120 may serve as a buffer layer.

The gate insulating layer 130 and the gate electrodes 141 and 142 are formed on the active layers 121 and 122 of the TFTs 11 and 12, respectively. An interlayer insulating layer 150 is formed on the gate insulating layer 130 and the gate electrodes 141 and 142, and the source / drain electrodes of the TFTs 11 and 12 formed to be insulated from the gate electrodes 141 and 142 thereon. 161 and 162 are disposed. In addition, the source / drain electrodes 161 and 162 are connected to the source / drain regions of the respective active layers 121 and 122 through the contact holes 150a and 150b, respectively. Since the description of the TFT has been described above in detail, further description thereof will be omitted.

Meanwhile, when the gate electrodes 141 and 142 and the source / drain electrodes 161 and 162 are formed, the charging capacitor Cst may be formed of the same material.

The passivation film 170 made of silicon oxide and / or silicon nitride is formed on the source / drain electrodes 161 and 162, and the planarization film 171 formed of acryl, BCB, polyimide, etc. is formed thereon. . The via hole 170a is formed in the passivation film 170 and the planarization film 171 so that any one of the source and drain electrodes 161 of the driving TFT 11 is exposed. The passivation film 170 and the planarization film 171 are not necessarily limited thereto, and only one layer may be provided.

The pixel electrode 180 of the organic light emitting element 15 is formed on the planarization layer 171. The pixel electrode 180 is connected to any one of the source and drain electrodes 161 through the via hole 170a.

The pixel defining layer 185 is formed on the pixel electrode 180 by an organic material such as acrylic, BCB, polyimide, or an inorganic material such as silicon oxide or silicon nitride. The pixel defining layer 185 is formed to cover the TFTs of the driving TFT 11, the switching TFT 12, and the like of the selection driving circuit, and to have an opening so that a predetermined portion of the pixel electrode 180 is exposed.

The organic layer 190 including the emission layer is coated on at least an opening through which the pixel defining layer 185 is exposed. The organic layer 190 may be formed on the entire surface of the pixel defining layer 185. In this case, the emission layer of the organic layer 190 may be patterned into red, green, and blue for each pixel to implement full color.

After the organic layer 190 is formed, the common electrode 195 of the organic light emitting diode 15 is formed. The common electrode 195 may be formed to cover all of the pixels, but is not limited thereto, and may be patterned.

The pixel electrode 180 and the common electrode 195 are insulated from each other by the organic layer 190, and apply a voltage having different polarities to the organic layer 190 to emit light in the organic layer 190. .

Meanwhile, the pixel electrode 180 functions as an anode electrode, and the common electrode 195 functions as a cathode electrode. Of course, the polarities of the pixel electrode 180 and the common electrode 195 may be reversed.

The pixel electrode 180 may be provided as a transparent electrode or a reflective electrode, and when used as a transparent electrode, may be formed of ITO, IZO, ZnO, or In ₂ O ₃ , and when used as a reflective electrode, Ag, Mg, After forming a reflecting film with Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and compounds thereof, ITO, IZO, ZnO or In ₂ O ₃ can be formed thereon.

Meanwhile, the common electrode 195 may also be provided as a transparent electrode or a reflective electrode. When the transparent electrode is used as a transparent electrode, since the common electrode 195 is used as a cathode, a metal having a low work function, that is, Li, Ca, or LiF is used. / Ca, LiF / Al, Al, Mg and their compounds are deposited so as to face the organic film 190, and thereon ITO, IZO, ZnO or In ₂ O ₃ The auxiliary electrode layer and the bus electrode line can be formed of a material for forming a transparent electrode, for example. And when used as a reflective electrode is formed by depositing the entire surface of Li, Ca, LiF / Ca, LiF / Al, Al, Mg and their compounds.

 The organic layer 190 may be a low molecular or high molecular organic layer. When the low molecular organic layer is used, a hole injection layer (HIL), a hole transport layer (HTL), and an organic emission layer (EML) are used. , An electron transport layer (ETL), an electron injection layer (EIL), etc. may be formed by stacking a single or a complex structure, and the usable organic materials may be copper phthalocyanine (CuPc), N, N'-di (naphthalen-1-yl) -N-N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N-N'-diphenyl-benzidine: NPB), Various applications are possible, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic layers are formed by the vacuum deposition method.

In the case of the polymer organic layer, the structure may include a hole transporting layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and PPV (Poly-Phenylenevinylene) and polyfluorene are used as the light emitting layer. By using a polymer organic material such as), it can be formed by screen printing or ink jet printing.

The OLED according to the present embodiment uses an excellent TFT manufactured by using the heat shielding layer according to the first embodiment, thereby enabling the uniform and fast pixel representation of the light emitting device and the realization of a large area display device.

5A through 5C are cross-sectional views schematically illustrating a crystallization process of a polycrystalline silicon thin film layer used as a semiconductor active layer of a polycrystalline semiconductor TFT according to the first or second embodiment.

5A schematically illustrates the step of forming a thermal barrier layer on the substrate 10. Although there is no buffer layer on the substrate 10 in this drawing, a buffer layer may be formed on the substrate and a heat shielding layer may be formed on the substrate as necessary.

FIG. 5B is a step of forming an amorphous silicon thin film layer 40a on the formed thermal barrier layer 30. Plasma Enhanced Chemical Vapor Deposition (POSMA) of about 700 to 2000 GPa of pure amorphous silicon is performed on a substrate. Vapor Deposition: Amorphous silicon thin film is deposited by PECVD or low pressure CVD.

When the amorphous silicon thin film is deposited by using the chemical vapor deposition (CVD) method, hydrogen may be contained in a large amount. Since hydrogen has a characteristic of leaving the thin film by heat, the process of dehydrogenation is performed by first heat treating the amorphous silicon. It is necessary to go through. This is because if the hydrogen is not removed in advance, the surface of the crystal thin film becomes very rough during crystallization, resulting in poor electrical characteristics. Although only the CVD method is mentioned above, this is only one example, and other vapor deposition methods apparent to those skilled in the art may be used.

5C schematically illustrates a step of crystallizing the polycrystalline silicon thin film layer 40b through laser annealing after the amorphous silicon thin film layer 40a is formed. As shown in FIG. 5C, a laser beam by the laser device 200 is illustrated. (Hatched rectangular portions below the laser device) are irradiated moving from the left side to the right side of the amorphous silicon thin film (arrow direction), whereby the already irradiated portion shows that the polycrystalline silicon thin film 40b is being formed.

As the crystallization method using the laser heat treatment, an Excimer Laser Annealing (ELA) method or an Sequential Lateral Solidification (SLS) method using an excimer laser, which is a high power pulse laser, is generally used.

In particular, the short wavelength of the excimer laser utilizes the energy concentration of the laser light, so that it is possible to perform precise heat treatment in a short time and locally, and the size of crystal grains of the polycrystalline silicon layer to be produced is generated by the thickness of the amorphous silicon film and the laser. It is possible to precisely control the temperature by varying the density of ultraviolet radiation and the temperature of the lower substrate.

The SLS method takes advantage of the fact that the grain of silicon grows in the direction perpendicular to the interface at the interface between the liquid and solid silicon, and appropriately controls the size of the laser energy and the shift of the irradiation range of the laser beam. By growing the grains of silicon by a predetermined length, the amorphous silicon thin film is crystallized.

In this crystallization method using laser, energy, that is, heat is transferred to the lower substrate, resulting in a problem of decreasing the grain growth of silicon and controlling the temperature of the lower substrate due to a decrease in thermal efficiency for crystallization. By forming a blocking layer under the amorphous silicon thin film layer to block heat transfer to the substrate during the laser heat treatment process, it is possible to solve the temperature control problem of the lower substrate and increase the thermal efficiency for crystallization to improve the grain growth of silicon.

By patterning the polycrystalline silicon thin film formed by the method as shown in FIG. 5C and activating it by impurity ion implantation, the semiconductor active layer of the TFT is formed, and the first insulating film (gate insulating film), gate electrode, and second insulating film are subsequently formed. (Interlayer insulating film), first and second contact holes, and forming first and second electrodes in contact with each contact hole, and the like, to fabricate a complete polycrystalline semiconductor TFT according to the first or second embodiment. Can be.

By manufacturing the polycrystalline semiconductor active layer through the manufacturing process as shown in Figs. 5a to 5c, it is possible to manufacture a polycrystalline semiconductor TFT of excellent characteristics including the semiconductor active layer of the high channel mobility described above in the first or second embodiment.

In addition, even in the case of using a non-heat-resistant substrate such as a glass material or a plastic material, not only the problem of improving the thermal efficiency of the crystallization of the amorphous semiconductor using the heat shield layer, but also the problem of deformation of the substrate due to heat transfer to the substrate is simultaneously I can solve it.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described in detail above, in the present invention, heat incident by a laser beam is transferred from an amorphous silicon film to a lower substrate by using a heat shielding layer in a crystallization process of an amorphous silicon thin film into a polycrystalline silicon thin film during a polycrystalline semiconductor TFT fabrication process. By blocking it, the characteristics of crystallization, that is, thermal efficiency for crystallization, can be improved, whereby a polycrystalline semiconductor TFT having excellent characteristics including a semiconductor active layer of high channel mobility can be manufactured.

In addition, the use of such TFTs enables the implementation of large area OLEDs with a uniform and fast pixel surface.

Furthermore, the present invention is particularly useful when manufacturing a polycrystalline semiconductor TFT using a metal substrate having high heat transfer and divergence due to its characteristics, and also a problem of deformation of the substrate due to heat transfer to the substrate when glass or plastic substrates are used. There are advantages to be solved.

Claims (15)

Board; A heat shield layer formed on the substrate; And A polycrystalline semiconductor active layer having a source, a drain, and a channel region formed on the thermal barrier layer, The thermal barrier layer is formed of yttria-stabilized zirconia (YSZ), an YSZ compound, or a rare-earth zirconates. delete According to claim 1, And a buffer layer between the substrate and the thermal barrier layer. According to claim 1, And the semiconductor active layer is polysilicon. The method according to any one of claims 1, 3 and 4, The substrate is a thin film transistor, characterized in that the metal substrate. The method of claim 5, The metal substrate is a thin film transistor, characterized in that the stainless steel (SUS), aluminum (AL) or titanium (Ti) substrate. Board; A heat shield layer formed on the substrate; A thin film transistor including a polycrystalline semiconductor active layer having a source, a drain, and a channel region formed on the heat blocking layer; And An organic light emitting device including a pixel electrode, an organic light emitting layer, and a common electrode formed on the thin film transistor; The heat shield layer is formed of yttria-stabilized zirconia (YSZ), an YSZ compound, or a rare-earth zirconates. delete The method of claim 7, wherein And the semiconductor active layer is polysilicon. The method according to claim 7 or 9, The substrate is an organic light emitting display device, characterized in that the metal substrate of stainless steel (SUS), aluminum (AL) or titanium (Ti). Forming a thermal barrier layer on the substrate; A second step of forming an amorphous semiconductor thin film layer on the heat shield layer; And A third step of crystallizing the amorphous semiconductor thin film layer into a polycrystalline semiconductor thin film layer using a laser heat treatment method, Block heat transfer to the substrate by using the heat shield layer in the laser heat treatment process of the third step, The thermal barrier layer is formed of yttria-stabilized zirconia (YSZ), YSZ compound or rare-earth zirconates (rare-earth zirconates), characterized in that the polycrystalline semiconductor crystallization method. delete The method of claim 11, wherein And said semiconductor is a silicon semiconductor. The method of claim 11, wherein The laser heat treatment method of the third step is an excimer laser crystallization (ELA) method or a sequential lateral solidification (SLS) method. The method according to any one of claims 11, 13 and 14, The substrate is a polycrystalline semiconductor crystallization method, characterized in that the metal substrate of stainless steel (SUS), aluminum (AL) or titanium (Ti).

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