KR20050122541A - Method of manufacturing thin film transistor, method of manufacturing display device, display device manufactured by that method, method of manufacturing active matrix type electroluminescence device, and active matrix type electroluminescence device manufactured by that method - Google Patents

Abstract

The present invention provides an etching stopper layer on a glass substrate so that the polycrystalline silicon thin film transistor, a display device having the same, or an active driving type electroluminescent device having the same can be applied to a flexible display device. Forming a thin film transistor on the etching stopper layer, providing a plastic substrate corresponding to the glass substrate on the thin film transistor, and etching and removing the glass substrate. It provides a method for manufacturing a thin film transistor, characterized in that it comprises a step.

Description

A method of manufacturing a thin film transistor, a method of manufacturing a display device, a display device manufactured according to the same, a method of manufacturing an active driven electroluminescent device, and an active driven electroluminescent device manufactured according thereto display device, display device manufactured by that method, method of manufacturing active matrix type electroluminescence device, and active matrix type electroluminescence device manufactured by that method}

The present invention relates to a method of manufacturing a thin film transistor, a method of manufacturing a display device, a display device manufactured according to the present invention, a method of manufacturing an active driven electroluminescent device, and an active driven electroluminescent device manufactured according to the present invention. A method of providing a thin film transistor on a plastic substrate, which can be applied to a flexible device, and a display device having the same, particularly a method of manufacturing an active driving type electroluminescent device provided on a plastic substrate and the method It relates to an electroluminescent device manufactured by.

Low-temperature polycrystalline silicon (LTPS) thin film transistors (TFTs), liquid crystal displays (LCDs) and electroluminescence displays (ELDs) including the thin film transistors are currently present. The market is expanding to display for mobile devices such as digital cameras, video cameras, portable information terminals (PDAs), and cellular phones.

The first characteristic of the low temperature polycrystalline silicon thin film transistor is that the electron mobility of the low temperature polycrystalline silicon is more than 100 times that of amorphous silicon, so that the current driving capability of the thin film transistor is high, and the size of the thin film transistor formed in each pixel is increased. It can be reduced. Therefore, it is possible to reduce the pixel size, that is, high definition, so that the panel can be miniaturized, which is optimal for a display for a mobile device.

The second feature is that the ON current ratio of each transistor of the N-channel and P-channel is balanced by factor 2, and the CMOS circuit can be configured. Therefore, a CMOS circuit can be integrated into a thin film transistor on the outer periphery of the panel, and the image signal input from the outside of the panel is once received therein and converted into a drive signal for data wiring and gate wiring connected to each pixel. Compared to the amorphous silicon thin film transistors that need to supply a signal, the number of input pins on the panel can be reduced. This is effective for improving reliability or impact resistance.

On the other hand, thinner, lighter and more unbreakable features are required for mobile applications. In order to manufacture thin and light, in addition to the method of using a thin glass substrate in the manufacturing, a method of making a thin glass substrate by a mechanical or chemical method after the production using an existing glass substrate was introduced. However, such a process is not only complicated but also can be easily broken, which makes it difficult to use practically.

In order to solve this problem, an attempt has been made to form a low temperature polycrystalline silicon thin film transistor on a plastic substrate. Even if the plastic is formed to a thickness of about 0.2 mm, it is hard to be broken, and the specific gravity is smaller than that of glass, so that the weight can be reduced to 1/5 or less as compared with the conventional glass substrate.

However, when fabricating a low temperature polycrystalline silicon thin film transistor, the temperature of the substrate is raised to 400 to 500 ° C., which is a problem when using a plastic substrate. The heat resistant temperature of the transparent plastic substrate, such as polycarbonate (PC) or polyethylsulfone (PES), is about 200 ° C to 300 ° C, which is much lower than the glass substrate. In addition, even when a polycrystalline silicon thin film transistor is manufactured using the plastic substrate as described above at a heat resistance temperature, the coefficient of thermal expansion (linear expansion coefficient) of the plastic substrate is 50 ppm / ° C. or higher. There was a problem that expansion caused by% may cause patterning errors, disconnection of wiring, and the like.

In order to solve this problem, in the March 2004 issue of the monthly display published in Japan, a method of providing a thin film transistor on a plastic substrate using the transfer method twice under the title of the latest trend of a plastic substrate low temperature polycrystalline silicon thin film transistor LCD. This is posted.

1 to 5 are cross-sectional views schematically illustrating processes of manufacturing a thin film transistor provided on a plastic substrate according to the method.

1 to 5, first, an etching stopper layer 20 is formed on an existing glass substrate 10, and then a low temperature is formed on the etching stopper layer 20 according to a conventional method. The polycrystalline silicon thin film transistor 30 is formed. As shown in FIG. 2, the temporary substrate 40 is attached to the thin film transistor 30 using a temporary adhesive or the like, and as shown in FIG. 3, the glass substrate is made using hydrofluoric acid (HF) or the like. (10) and the etching stopper layer 20 are removed. After the above process, as shown in FIG. 4, the plastic substrate 70 is attached to the lower surface of the thin film transistor 30 with an adhesive, and finally, the temporary substrate 40 is peeled off. As shown, the thin film transistor 30 provided on the plastic substrate 70 is manufactured.

However, the above manufacturing method has a problem that the process is too complicated, such as using the temporary substrate 40 and transferring twice, and also to form an electroluminescent element or the like on the thin film transistor manufactured by the above method. In the process and the like, there is a problem that the process is overly complicated and the same process is repeated.

The present invention is to solve the various problems including the above problems, which can be applied to a flexible device, a method of manufacturing a thin film transistor provided on a plastic substrate, provided with a thin film transistor provided on the plastic substrate It is an object of the present invention to provide a display device and a display device manufactured using the method, in particular, a method of manufacturing an active drive type electroluminescent device provided on a plastic substrate and an electroluminescent device manufactured using the method.

In order to achieve the above object and various other objects, the present invention provides a method for forming an etching stopper layer on a glass substrate, forming a thin film transistor on the etching stopper layer, and forming an upper portion of the thin film transistor. A method of manufacturing a thin film transistor, comprising the steps of: providing a plastic substrate corresponding to the glass substrate, and etching and removing the glass substrate.

According to another aspect of the present invention, a step of forming a protective film on the thin film transistor between the step of forming a thin film transistor on the etching stopper layer, and the step of providing a plastic substrate on the thin film transistor. It can be provided.

According to still another aspect of the present invention, the forming of the thin film transistor on the etching stopper layer may include forming a source electrode and a drain electrode on the etching stopper layer, and contacting the source electrode and the drain electrode, respectively. Forming a semiconductor layer, forming a gate insulating film over the glass substrate while covering the semiconductor layer, and forming a gate electrode on the gate insulating film.

According to another feature of the invention, the step of forming a thin film transistor on the etching stopper layer, forming a gate electrode on the etching stopper layer, and covering the gate electrode over the entire glass material substrate Forming a gate insulating film, forming a semiconductor layer on the gate insulating film, and forming a source electrode and a drain electrode on the semiconductor layer, respectively, in contact with the semiconductor layer.

According to still another feature of the present invention, the forming of the semiconductor layer may be performed by applying an amorphous silicon layer and crystallizing the amorphous silicon layer into a polycrystalline silicon layer.

The present invention also provides a method for forming an etching stopper layer on a glass substrate, forming a thin film transistor on the etching stopper layer, and forming the glass substrate on the thin film transistor. Forming a display element connected to the thin film transistor at a position opposite to the plastic material substrate with respect to the thin film transistor; It provides a method of manufacturing a display device characterized in that it comprises a.

According to another aspect of the present invention, between the step of forming a thin film transistor on the etching stopper layer and the step of providing a plastic material substrate corresponding to the glass substrate on the thin film transistor, It may be further provided with the formation of a protective film.

According to another feature of the invention, the etching stopper layer may be formed of silicon nitride or silicon oxide.

According to another feature of the present invention, between the step of etching and removing the glass substrate, and forming a display element connected to the thin film transistor in the opposite position of the plastic substrate with respect to the thin film transistor, The method may further include forming an alignment layer, a spacer, or a pixel defining layer by patterning the etching stopper layer.

The present invention also provides a display device manufactured using the above method, in order to achieve the above object.

In order to achieve the above object, the present invention also provides a method for forming an etching stopper layer on a glass substrate, forming a pixel electrode on the etching stopper layer, and covering the pixel electrode. Forming a first passivation layer over the entire surface of the substrate; forming a thin film transistor connected to the pixel electrode on the first passivation layer; and a plastic substrate corresponding to the glass substrate on the thin film transistor. Etching, removing, and etching the glass substrate, forming an intermediate layer including at least a light emitting layer on an opposite surface of the pixel electrode in the direction of the plastic substrate; And forming an opposite electrode on the entire surface of the plastic substrate while covering the intermediate layer. It provides a process for the production of active matrix electroluminescent device.

According to another aspect of the present invention, between the step of forming a thin film transistor connected to the pixel electrode on the first passivation layer, and providing a plastic material substrate corresponding to the glass substrate on the thin film transistor The method may further include forming a second passivation layer on the thin film transistor.

According to another feature of the invention, the etching stopper layer may be formed of silicon nitride or silicon oxide.

According to another feature of the invention, between the step of etching and removing the glass substrate and the step of forming an intermediate layer including at least a light emitting layer on the opposite side of the surface of the plastic substrate of the pixel electrode, The method may further include forming a pixel defining layer by patterning the etching stopper layer.

According to still another aspect of the present invention, the forming of the thin film transistor connected to the pixel electrode on the first passivation layer may include forming a contact hole in the first passivation layer to expose the pixel electrode; Forming a metal layer on the passivation layer, patterning the metal layer to form a source electrode, a drain electrode connected to the pixel electrode through the contact hole, and contacting the drain electrode and the source electrode, respectively. The method may include forming a semiconductor layer, forming a gate insulating film over the glass substrate while covering the semiconductor layer, and forming a gate electrode on the gate insulating film.

According to still another aspect of the present invention, the forming of the thin film transistor connected to the pixel electrode on the first passivation layer may include forming a gate electrode on the first passivation layer, and covering the gate electrode. Forming a gate insulating film over the glass substrate, forming a semiconductor layer on the gate insulating film, forming a contact hole to expose the pixel electrode to the gate insulating film and the first passivation film, and Forming a metal layer on the entire surface of the glass substrate while covering the semiconductor layer; patterning the metal layer to form a source electrode in contact with the semiconductor layer; a drain in contact with the semiconductor layer and connected to the pixel electrode through the contact hole. It may be provided with the step of forming an electrode.

According to still another feature of the present invention, the forming of the semiconductor layer may be performed by applying an amorphous silicon layer and crystallizing the amorphous silicon layer into a polycrystalline silicon layer.

The present invention also provides an active drive electroluminescent device manufactured using the above method, in order to achieve the above object.

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

6 and 7 are cross-sectional views schematically illustrating manufacturing processes of a thin film transistor provided on a plastic substrate according to an exemplary embodiment of the present invention.

First, referring to FIG. 6, an etching stopper layer 120 is formed on an existing glass substrate 110, and a thin film transistor 130 is formed on the etching stopper layer 120. The plastic substrate 170 corresponding to the glass substrate 110 is provided on the upper portion 130. Thereafter, the glass substrate 110 is etched and removed, and the structure is turned upside down so that the plastic substrate 170 is located below, and the thin film transistor formed on the plastic substrate 170 as shown in FIG. 130).

After the thin film transistor 130 is formed on the glass substrate 110 having a sufficient thickness as described above, a plastic substrate 170 having a desired thin thickness is provided on the thin film transistor 130 and the thick glass substrate is formed. By removing the 110, the thin film transistor formed on the thin plastic substrate 170 can be obtained.

In the above-described manufacturing process, between the forming of the thin film transistor 130 on the etching stopper layer 120, and the step of providing a plastic substrate 170 on the thin film transistor 130, the thin film A protective film (not shown) may be further formed on the transistor 130. In this case, a protective film is finally formed on the plastic substrate 170, and the thin film transistor 130 is disposed on the protective film. The protective film may be formed to maintain smoothness of the plastic substrate 170 and to prevent impurities from penetrating into the thin film transistor.

In addition, as will be described later, all of the etching stopper layer 120 may be removed in the step of removing the glass material substrate 110, but other applications without removing all of the etching stopper layer 120 may be performed. As described above, it may be used as a pixel defining film or planarization film in an electroluminescent display element.

8 to 11 are cross-sectional views schematically illustrating processes of obtaining various types of thin film transistors in the above manner. 8 and 9 show processes for finally obtaining an inverted staggered type thin film transistor 130 formed on the plastic substrate 170, and FIGS. 10 and 11 finally show a plastic substrate ( 170 are cross-sectional views schematically showing processes for obtaining a staggered type thin film transistor 130 formed on it.

Referring to FIG. 8, the etching stopper layer 120 is formed on the glass substrate 110 as described above, and then chromium (Cr) or molybdenum (Mo) is formed on the etching stopper layer 120. The wiring metal is deposited and patterned to form the source electrode 134 and the drain electrode 135. Thereafter, as described below, a semiconductor layer 136 is formed to contact the source electrode 134 and the drain electrode 135, respectively. Silicon oxide (SiO ₂ ) or silicon nitride (SiN _x ) may be deposited on the entire surface of the glass substrate 110 while covering the semiconductor layer 136 to form a gate insulating layer 137. The gate electrode 133 is formed by depositing and then patterning a conductive material for gate wiring on the 137. After forming the passivation layer 160 thereon, the passivation layer 160 includes a plastic substrate 170 corresponding to the glass substrate 110. After the above process, the glass substrate 110 is etched and removed, and the plastic substrate 170 is inverted so that the plastic substrate 170 is located at the lower side, as shown in FIG. 9. The inverted staggered thin film transistor 130 formed on the () is obtained.

Meanwhile, in the process of manufacturing a staggered thin film transistor, referring to FIG. 10, the etching stopper layer 220 is formed on the glass substrate 210 as described above, and the etching stopper layer 220 is formed on the etching stopper layer 220. The gate electrode 233 is formed by depositing and patterning a conductive material for gate wiring. Silicon oxide (SiO ₂ ), silicon nitride (SiN _x ), or the like is deposited on the entire surface of the glass substrate 210 while covering the gate electrode 233 to form a gate insulating layer 237. Thereafter, a semiconductor layer 236 is formed on the gate insulating layer 237 as described below, and a source electrode 234 and a drain electrode (respectively contacting the semiconductor layer 236 on the semiconductor layer 236). 245 is formed by depositing and patterning a metal for wiring. After forming the passivation layer 260 thereon, the passivation layer 260 includes a plastic substrate 270 corresponding to the glass substrate 210. After the above process, the glass substrate 210 is etched and removed, and the plastic substrate 270 is inverted so that the plastic substrate 270 is located at the lower side. The staggered thin film transistor 230 is formed on the ().

Of course, the present invention can also be applied to the manufacture of thin film transistors having a structure different from those of the thin film transistors 130 and 230 shown in FIGS. 8 to 11, such as a coplanar type thin film transistor.

As described above with reference to FIGS. 8 to 11, the etching stopper layers 120 and 220 are formed on the sufficiently thick glass material substrates 110 and 210, and the thin film transistors 130 and 230 are formed. After having the desired thin thickness plastic substrates 170 and 270 on the transistors 130 and 230, the thick glass substrates 110 and 210 are removed to remove the thick glass substrates 170 and 270. The thin film transistors 130 and 230 formed on the 270 may be obtained.

In addition, a polycrystalline silicon thin film transistor formed on a plastic substrate may be obtained through the manufacturing process as described above.

That is, in the above-described process, the forming of the semiconductor layers 136 and 236 may be performed by applying an amorphous silicon layer and crystallizing the amorphous silicon layer into a polycrystalline silicon layer. Can be.

In more detail, first, an amorphous silicon layer is formed by chemical vapor deposition (CVD) or sputtering, and the like, and then the amorphous silicon layer is converted into a polycrystalline silicon layer.

The polycrystallization process of the amorphous silicon layer is divided into a low temperature process and a high temperature process according to the process temperature. However, the high temperature process is required to use the expensive quartz substrate having a high thermal resistance because the temperature conditions above the deformation temperature of the substrate is used, and thus the low temperature process is mainly used. The low temperature process can be classified into laser annealing, metal induced crystallization (MIC), etc., mainly by irradiating a laser to the amorphous silicon layer, melting it into a liquid phase, and cooling the grain to grow grain. Sequential lateral sequential crystallization, using the fact that excimer laser annealing, or grains of polycrystalline silicon, grows perpendicular to its interface at the boundary between the laser-irradiated liquid region and the non-irradiated solid-state region A polycrystalline silicon layer is formed using a lateral solidification process.

However, in the crystallization process as described above, even in the case of the low temperature process, as described above, a process of 200 ° C to 300 ° C or more, which is a heat resistance temperature of the plastic material substrate, becomes. Therefore, as described above, after converting the amorphous silicon layer into the polycrystalline silicon layer by using the glass material substrate that can withstand such a temperature without deformation and completing the polycrystalline silicon thin film transistor, the plastic substrate on the top of the polycrystalline silicon thin film transistor By removing the glass substrate, the polycrystalline silicon thin film transistor formed on the plastic substrate can be obtained.

Of course, after the polysilicon process of the amorphous silicon layer as described above, the polycrystalline silicon layer may be patterned appropriately, and the process of ion implanting and activating n-type or p-type impurities into the semiconductor layer may be performed. It may be rough. This is also the same in the embodiments described later.

Meanwhile, in addition to manufacturing the thin film transistor formed on the plastic substrate as described above, various various devices including the thin film transistor manufactured as described above may be manufactured. In particular, a flexible display device may be manufactured by manufacturing a display device having a thin film transistor formed on the plastic substrate as described above. Of course, even in this case, a protective film may be formed between the plastic substrate and the thin film transistor to maintain smoothness of the plastic substrate and to prevent impurities from penetrating into the thin film transistor.

In the process of manufacturing the flexible display device as described above, the etching stopper layer may be removed in the step of etching and removing the glass substrate, but the glass substrate is removed without removing the etching stopper layer. Subsequently, the etching stopper layer may be patterned to form a pixel defining layer in the case of an electroluminescent device, or an alignment layer or a spacer in the case of a liquid crystal display device.

In this case, the etching stopper layer may be formed of a material such as a pixel defining layer, an alignment layer, or a spacer, and may be formed of, for example, silicon oxide or silicon nitride.

12 to 19 are cross-sectional views schematically illustrating manufacturing processes of an active driving type electroluminescent device formed on a plastic material substrate according to an exemplary embodiment of the present invention.

Referring to FIG. 12, an etching stopper layer 320 is formed on the glass substrate 310, and a pixel electrode 382 is formed on the etching stopper layer 320. The pixel electrode 382 may be formed 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 . When used as a reflective electrode, a reflective film is formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof, and then ITO, IZO, ZnO or In ₂ O ₃ thereon. Can be formed.

After the pixel electrode 382 is formed, the first passivation layer 350 is formed over the entire glass material substrate 310 while covering the pixel electrode 382. As described below, a thin film transistor 330 connected to the pixel electrode 382 is formed on the first passivation layer 350. Thereafter, as illustrated in FIG. 16, a plastic substrate 370 corresponding to the glass substrate 310 is provided on the thin film transistor 330. In this case, before the plastic substrate 370 is provided on the thin film transistor 330, a second passivation layer 360 may be formed on the thin film transistor 330. 17, the glass substrate 310 is etched and removed.

In this case, after the glass substrate 310 is removed by etching, an intermediate layer including at least a light emitting layer on a surface opposite to the surface of the plastic substrate 370 of the pixel electrode 382 as shown in FIG. 19. Before forming the 383, all of the etching stopper layer 320 may be removed, but after the glass material substrate 310 is removed without removing the etching stopper layer 320, the etching stopper layer ( The pixel defining layer 322 may be formed by patterning 320 as illustrated in FIG. 18.

In this case, the etching stopper layer 320 may be formed of a material of the pixel defining layer 322. For example, the etching stopper layer 320 may be formed of silicon oxide or silicon nitride. As illustrated in FIG. 18, the pixel defining layer 322 is formed between the pixel electrodes 382. In addition to defining a light emitting area, an intermediate layer, which will be described later, is cut off at an edge of the pixel electrode 382. By preventing a phenomenon in which an electric field is concentrated, a short circuit between the pixel electrode 382 and the counter electrode described later is prevented.

After the above process, as shown in FIG. 19, an intermediate layer 383 including at least an emission layer is formed on an opposite surface of the pixel electrode 382 in the direction of the plastic substrate 370. An opposite electrode 384 is formed on the intermediate layer 383 or on the entire surface of the plastic substrate 370 while covering the intermediate layer 383. In addition, an active driving type electroluminescent device can be manufactured by forming a sealing member or the like not shown above the counter electrode 384.

In detail, the counter electrode 384 may be formed of a transparent electrode or a reflective electrode like the pixel electrode 382 described above. When the counter electrode 384 is used as a transparent electrode, Li, Ca, LiF / After depositing Ca, LiF / Al, Al, Ag, Mg, or a compound thereof toward the intermediate layer 383, the auxiliary electrode layer with a material for forming a transparent electrode such as ITO, IZO, ZnO, or In ₂ O ₃ thereon Alternatively, the bus electrode line may be formed. When used as a reflective electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, or a compound thereof is formed by full deposition. However, the present invention is not limited thereto, and organic materials such as a conductive polymer may be used as the pixel electrode 382 and the counter electrode 384.

The pixel electrode 382 functions as an anode electrode, and the counter electrode 384 functions as a cathode electrode. Of course, the polarities of the pixel electrode 382 and the counter electrode 384 may be reversed. .

Meanwhile, referring to the intermediate layer 383 interposed between the pixel electrode 382 and the counter electrode 384, the intermediate layer 383 may be used to electrically drive the pixel electrode 382 and the counter electrode 384. The light emitting layer has a light emitting layer, and the electroluminescent device may be classified into an organic electroluminescent device or an inorganic electroluminescent device according to the type of the intermediate layer 383.

In the case of an organic electroluminescent device, it may be formed of a low molecular organic film or a polymer organic film.

In the case of using a low molecular organic film, the intermediate layer 383 may include a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), and an electron transport layer (ETL). And an electron injection layer (EIL), etc., may be formed by stacking a single or complex structure, and the usable organic materials may also be formed of copper phthalocyanine (CuPc), N, N-di (naphthalene-1- Yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), tris-8-hydroxyquinoline aluminum (tris- 8-hydroxyquinoline aluminum) (Alq3), etc. can be applied in various ways. The low molecular weight organic film may be formed by heating and depositing an organic material in a vacuum. Of course, the structure of the intermediate layer 383 is not necessarily limited to the above, and may be configured as various layers as necessary.

When the polymer organic film is used, the intermediate layer 383 may be generally formed of a hole transport layer (HTL) and a light emitting layer (EML). The polymer hole transport layer may be formed by ink jet printing or spin coating using polyethylene dihydroxythiophene (PEDOT: poly- (2,4) -ethylene-dihydroxy thiophene) or polyaniline (PANI: polyaniline). Can be. The polymer organic light emitting layer may be formed of PPV, Soluble PPV's, Cyano-PPV, polyfluorene, or the like, and may form a color pattern by a conventional method such as inkjet printing, spin coating, or thermal transfer using a laser. Can be. Of course, even in such a polymer organic layer, the structure of the intermediate layer 383 is not necessarily limited to the above, and may be configured as various layers as necessary.

In the case of an inorganic electroluminescent device, the intermediate layer 383 may be formed of an inorganic layer, which may be formed of an emission layer and an insulating layer interposed between the emission layer and the electrode. Of course, the structure of the intermediate layer 383 is not necessarily limited to the above, and may be configured as various layers as necessary.

The light emitting layer is ZnS, SrS, CaS Metals such as sulfides or _{CaGa 2 S 4, SrGa 2 S} 4 alkaline-earth potassium sulfide such as, and Mn, Ce, Tb, Eu, Tm, Er, Pr, transition, including Pb, etc. such as metal or alkaline rare earth metal It may be formed of light emitting center atoms.

Through the above process, an electroluminescent device having a thin film transistor formed on the plastic substrate 370, that is, an active driving type electroluminescent element formed on the plastic substrate 370 can be manufactured.

12 to 16, the process of forming the thin film transistor 330, and more particularly, the inverted staggered thin film transistor on the first passivation layer 350, will be described.

Referring to FIG. 12, after forming the first passivation layer 350, a contact hole 350a is formed in the first passivation layer 350 so that a part of the pixel electrode 382 is exposed. As described above, the metal layer 331 is formed on the first passivation layer 382. The metal layer 331 is connected to the pixel electrode 382 through the contact hole 350a.

After forming the metal layer 331 as described above, the metal layer 331 is patterned, and as shown in FIG. 14, through the source electrode 334 and the contact hole 350a to the pixel electrode 382. A drain electrode 335 to be connected is formed. As shown in FIG. 15, a semiconductor layer 336 is formed to be in contact with the drain electrode 335 and the source electrode 334, and the semiconductor layer 336 is covered with the semiconductor layer 336 as shown in FIG. 16. After the gate insulating film 337 is formed on the entire glass material substrate 310, the gate electrode 333 is formed on the gate insulating film 337 to form the thin film transistor 330.

Through the above processes, after forming the thin film transistor 330 on the glass substrate 310 having a sufficient thickness as described above, the plastic substrate 370 of the desired thin thickness is placed on the upper portion of the thin film transistor 330. By forming the electroluminescent device after removing the thick glass material substrate 310, the electroluminescent device having an inverted staggered thin film transistor formed on a thin plastic substrate 370 can be manufactured. have. In addition, as described above, in the forming of the thin film transistor 330, the amorphous silicon layer may be coated and crystallized to form a polycrystalline silicon thin film transistor when the semiconductor layer 336 is formed. Of course. This makes it possible to manufacture thin, light and flexible active-driven electroluminescent devices.

20 to 24 are cross-sectional views schematically showing manufacturing processes of an active driving type electroluminescent device formed on a plastic material substrate according to another preferred embodiment of the present invention. The cross-sectional views schematically illustrate the manufacturing processes of the electroluminescent device forming the thin film transistor.

Referring to FIG. 20, an etching stopper layer 420 is formed on the glass substrate 410, and a pixel electrode 482 is formed on the etching stopper layer 420. After forming the pixel electrode 482, the first passivation layer 450 is formed over the entire glass material substrate 410 while covering the pixel electrode 482. As described below, a thin film transistor 430 connected to the pixel electrode 482 is formed on the first passivation layer 450. Thereafter, as illustrated in FIG. 23, a plastic substrate 470 corresponding to the glass substrate 410 is provided on the thin film transistor 430. In this case, before the plastic substrate 470 is provided on the thin film transistor 430, a second passivation layer 460 may be formed on the thin film transistor 430. Thereafter, the glass substrate 410 is removed by etching, and as shown in FIG. 24, an intermediate layer including at least an emission layer on an opposite surface of the pixel electrode 482 in the direction of the plastic substrate 470. Prior to forming 483, all of the etching stopper layer 420 may be removed, but after removing the glass material substrate 410 without removing the etching stopper layer 420, the etching stopper layer ( The pixel defining layer 422 may also be formed by patterning the 420.

After the above process, as shown in FIG. 24, an intermediate layer 483 including at least a light emitting layer is formed on an opposite surface of the pixel electrode 482 in the direction of the plastic substrate 470. An opposite electrode 484 is formed on the intermediate layer 483 or on the entire surface of the plastic substrate 470 while covering the intermediate layer 483. By forming a sealing member or the like, which is not shown on the counter electrode 484, an active driving type electroluminescent device having a staggered thin film transistor 430 formed on the plastic substrate 470 may be manufactured. have. The material of the pixel electrode 482, the counter electrode 484, and the intermediate layer 483 and the process of forming the same are the same as in the above-described embodiment.

20 to 22, a process of manufacturing the thin film transistor 430 will be briefly described.

First, as shown in FIG. 20, a gate electrode 433 is formed on the first passivation layer 450, and the gate insulating layer 437 is formed on the entire surface of the glass substrate 410 while covering the gate electrode 433. To form. A semiconductor layer 436 is formed on the gate insulating film 437. In this case, the semiconductor layer 436 may be coated with amorphous silicon, crystallized therein, and then patterned, or may be activated by injecting appropriate ions.

21, a contact hole 450a is formed in the gate insulating layer 437 and the first passivation layer 450 to expose a portion of the pixel electrode 482, and the semiconductor layer 436 is formed. The metal layer 431 is formed on the entire surface of the glass substrate 410 while covering. Thereafter, as shown in FIG. 22, the metal layer 431 is patterned, and the source electrode 434 is in contact with the semiconductor layer 436 and the semiconductor layer 436 is in contact with the contact hole 450a. The thin film transistor 43 is formed by forming a drain electrode 435 connected to the pixel electrode 482.

Through the processes described above, after forming the thin film transistor 430 on the glass substrate 410 having a sufficient thickness as described above, the plastic substrate 470 having a desired thin thickness is formed on the upper portion of the thin film transistor 430. By forming the electroluminescent device after removing the thick glass material substrate 410, and formed on the thin plastic material substrate 470, an electroluminescent device having an inverted staggered thin film transistor formed on a thin plastic substrate 470 can be manufactured. have. In addition, as described above, in the forming of the thin film transistor 430 in the present invention, an amorphous silicon layer may be coated and crystallized to form a polycrystalline silicon thin film transistor when the semiconductor layer 436 is formed. Of course. This makes it possible to manufacture thin, light and flexible active-driven electroluminescent devices.

Meanwhile, referring to FIGS. 19 and 24, the structures of the thin film transistors 330 and 430 of the active driving type electroluminescent device manufactured according to the present invention are different from those of the thin film transistor of the general active driving type electroluminescent device. have. That is, among the electrodes 333, 334, 335, 433, 434, and 435 of the thin film transistor provided under the electroluminescent device, the electrodes 335 and 435 connected to the pixel electrodes 382 and 482 of the electroluminescent device. In the structure of, the electrodes 335 and 435 connected to the pixel electrodes 382 and 482 of the electroluminescent device protrude toward the pixel electrodes 382 and 482 of the electroluminescent device to the pixel electrodes 382 and 482. You can see that it is connected to). This is generally different from the structure of a general active driving type electroluminescent device in which the pixel electrodes 382 and 482 of the electroluminescent device protrude toward the electrode of the thin film transistor and are connected to the electrodes of the thin film transistor.

The active driving type electroluminescent device according to the present invention may be formed on a plastic substrate other than a glass material as described above by using the above structure, thereby forming a flexible display device or the like.

Meanwhile, in the above-described embodiments, only the case of the active driving type electroluminescent device has been described. However, as described above, any other display device having a thin film transistor can be applied to any device, for example, a thin film transistor liquid crystal display. The present invention may be applied to a display device such as a TFT LCD. The structure of the liquid crystal display panel is briefly described as follows.

 Culture layers for aligning the liquid crystal layer are provided between the first substrate and the second substrate facing each other, a pixel electrode is provided between the culture layer and the first substrate, the opposite electrode is provided between the culture layer and the second substrate A color filter layer is provided between the second substrate and the counter electrode.

The first polarizing layer is provided on the surface opposite the surface of the first substrate in the second substrate direction, and the second polarizing layer is provided on the surface opposite the surface of the second substrate in the first substrate direction. The upper surface is provided with a protective film.

In the liquid crystal panel having the above structure, the pixel electrode is connected to the thin film transistor formed on the plastic substrate through the above-described process, and thus, between the pixel electrode and the counter electrode by an external signal controlled by the thin film transistor. A potential difference is formed on the substrate, and the arrangement of the liquid crystal layer is determined by the potential difference, and the visible light supplied from a back light unit (BLU) provided under the first substrate of the liquid crystal panel according to the arrangement of the liquid crystal layer. Light rays are shielded or passed through, and the passed light becomes colored as it passes through the color filter layer to produce an image.

The thin film transistor formed on the plastic substrate according to the present invention as described above may be provided in any device having a flexible thin film transistor such as a flexible electronic sheet, a smart card, and the like other than the display device. Of course.

A method of manufacturing a thin film transistor formed on the plastic substrate of the present invention made as described above, a method of manufacturing a display device having a thin film transistor formed on the plastic substrate, a thin film formed on the plastic substrate manufactured by the method According to a display device having a transistor, a method of manufacturing an active driving type electroluminescent element formed on a plastic substrate, and an active driving type electroluminescent element formed on a plastic substrate manufactured by the method, the following effects are obtained. Can be.

First, after the thin film transistor is formed on a glass substrate having a sufficient thickness, a thin plastic substrate having a desired thin thickness is provided on the thin film transistor, and the thick glass substrate is removed to form a thin plastic substrate. Thin film transistors can be obtained through a simple process.

Second, a polycrystalline silicon thin film transistor formed on a plastic substrate can be obtained.

Third, various flexible devices including a thin film transistor formed on a plastic substrate, particularly a flexible display device, can be manufactured.

Fourth, an electroluminescent device having a thin film transistor formed on a plastic substrate can be manufactured. In this case, by forming an pixel defining layer by patterning the etching stopper layer in the process, the process can be simplified and the cost can be reduced. have.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand 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.

1 to 5 are cross-sectional views schematically showing manufacturing processes of a thin film transistor provided on a conventional plastic substrate.

6 and 7 are cross-sectional views schematically illustrating manufacturing processes of a thin film transistor provided on a plastic substrate according to an exemplary embodiment of the present invention.

8 and 9 are cross-sectional views schematically illustrating manufacturing processes of a thin film transistor provided on a plastic substrate according to another exemplary embodiment of the present invention.

10 and 11 are cross-sectional views schematically illustrating manufacturing processes of a thin film transistor provided on a plastic substrate according to another exemplary embodiment of the present invention.

12 to 19 are cross-sectional views schematically showing manufacturing processes of an active driving type electroluminescent device provided on a plastic material substrate according to an exemplary embodiment of the present invention.

20 to 24 are cross-sectional views schematically illustrating manufacturing processes of an active driving type electroluminescent device provided on a plastic material substrate according to another exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10, 110, 210, 310, 410: glass substrate

20, 120, 220, 320, 420: etching stopper layers 322, 422: pixel defining layer

30, 130, 230, 330: thin film transistors 331, 431: metal layer

133, 233, 333, 433: gate electrode 134, 234, 334, 434: source electrode

135, 235, 335, 435, drain electrode 136, 236, 336, 436: semiconductor layer

137, 237, 337, 437: gate insulating film 40: temporary substrate

350, 450: protective film 350a, 450a: contact hole

160, 260, 360, 460: Shield

70, 170, 270, 370, 470: plastic substrate 382, 482: pixel electrode

383, 483: intermediate layer 384, 484: counter electrode

Claims (19)

Forming an etching stopper layer on the glass substrate; Forming a thin film transistor on the etching stopper layer; Providing a plastic substrate corresponding to the glass substrate on the thin film transistor; And And etching the glass substrate to remove the thin film transistor. The method of claim 1, Forming a passivation layer on the thin film transistor between the step of forming a thin film transistor on the etch stopper layer and the step of providing a plastic substrate on the thin film transistor. Manufacturing method. The method of claim 1, Forming a thin film transistor on the etching stopper layer, Forming a source electrode and a drain electrode on the etching stopper layer; Forming a semiconductor layer in contact with the source electrode and the drain electrode, respectively; Forming a gate insulating film over the glass substrate while covering the semiconductor layer; And And forming a gate electrode on the gate insulating film. The method of claim 1, Forming a thin film transistor on the etching stopper layer, Forming a gate electrode on the etching stopper layer; Forming a gate insulating film over the entire glass material substrate while covering the gate electrode; Forming a semiconductor layer on the gate insulating film; And Forming a source electrode and a drain electrode on the semiconductor layer, the source electrode and the drain electrode respectively contacting the semiconductor layer. The method according to claim 3 or 4, The forming of the semiconductor layer may include applying an amorphous silicon layer and crystallizing the amorphous silicon layer into a polycrystalline silicon layer. Forming an etching stopper layer on the glass substrate; Forming a thin film transistor on the etching stopper layer; Providing a plastic substrate corresponding to the glass substrate on the thin film transistor; Etching to remove the glass substrate; And And forming a display element connected to the thin film transistor at a position opposite to the plastic substrate with respect to the thin film transistor. The method of claim 6, Forming a thin film transistor on the etching stopper layer; And forming a protective film on the thin film transistor between the steps of providing a plastic material substrate corresponding to the glass material substrate on the thin film transistor. The method of claim 6, And the etching stopper layer is formed of silicon nitride or silicon oxide. The method of claim 6, Etching the glass substrate and removing the glass substrate; and forming a display element connected to the thin film transistor at a position opposite to the plastic substrate with respect to the thin film transistor, and patterning the etching stopper layer to form an alignment layer. And forming a spacer or a pixel definition layer. Display device manufactured using the method of claim 6. Forming an etching stopper layer on the glass substrate; Forming a pixel electrode on the etching stopper layer; Forming a first passivation layer over the entire glass substrate while covering the pixel electrode; Forming a thin film transistor connected to the pixel electrode on the first passivation layer; Providing a plastic substrate corresponding to the glass substrate on the thin film transistor; Etching to remove the glass substrate; Forming an intermediate layer including at least an emission layer on a surface opposite to the surface of the pixel electrode in the plastic substrate direction; And And forming a counter electrode on the intermediate layer or on the entire surface of the plastic material substrate while covering the intermediate layer. The method of claim 11, Forming a thin film transistor connected to the pixel electrode on the first passivation layer, and providing a plastic substrate corresponding to the glass substrate on the thin film transistor, and forming a second passivation layer on the thin film transistor. Method for manufacturing an active-driven electroluminescent device, characterized in that it further comprises forming a. The method of claim 11, The etching stopper layer is a method of manufacturing an active driven electroluminescent device, characterized in that formed of silicon nitride or silicon oxide. The method of claim 11, Patterning the etching stopper layer between the step of etching and removing the glass substrate and forming an intermediate layer including at least a light emitting layer on a surface opposite to the surface of the plastic substrate of the pixel electrode. A method of manufacturing an active driven electroluminescent device, further comprising the step of forming a film. The method of claim 11, Forming a thin film transistor connected to the pixel electrode on the first passivation layer, Forming a contact hole in the first passivation layer to expose the pixel electrode; Forming a metal layer on the first passivation layer; Patterning the metal layer to form a source electrode and a drain electrode connected to the pixel electrode through the contact hole; Forming a semiconductor layer in contact with the drain electrode and the source electrode, respectively; Forming a gate insulating film over the glass substrate while covering the semiconductor layer; And And forming a gate electrode on the gate insulating film. The method of claim 11, Forming a thin film transistor connected to the pixel electrode on the first passivation layer, Forming a gate electrode on the first passivation layer; Forming a gate insulating film over the glass substrate while covering the gate electrode; Forming a semiconductor layer on the gate insulating film; Forming a contact hole in the gate insulating layer and the first passivation layer to expose the pixel electrode; Forming a metal layer over the glass substrate while covering the semiconductor layer; And And patterning the metal layer to form a source electrode in contact with the semiconductor layer, and a drain electrode in contact with the semiconductor layer and connected to the pixel electrode through the contact hole. Method of manufacturing the device. The method according to claim 15 or 16, The forming of the semiconductor layer may include applying an amorphous silicon layer and crystallizing the amorphous silicon layer into a polycrystalline silicon layer. An active driven electroluminescent device manufactured using the method of claim 15. An active driven electroluminescent device manufactured using the method of claim 16.