KR20080004231A - Method of manufacturing thin film transistor substrate, and method of manufacturing organic light emitting display apparatus using the same - Google Patents

Abstract

A method of manufacturing a thin film transistor substrate, and a method of manufacturing an organic light emitting display apparatus using the same are provided to manufacture the thin film transistor substrate provided with a thin film transistor on a flexible substrate. A method of manufacturing a thin film transistor substrate includes the steps of: forming a polymer layer(103) on a support substrate(101); forming a first electrode(131) on the polymer layer; forming a thin film transistor(120) electrically connected to the first electrode; forming a planarizing film(105) so as to cover the thin film transistor; disposing a substrate(102) on the planarizing film; and separating the support substrate by nitrocarburizing the polymer layer by radiating a laser beam. The step of forming the thin film transistor forming a first insulating film so that a part of the first electrode is exposed on the first electrode; and forming a semiconductor layer(127), and a source electrode and a drain electrode(123) which are in contact with the semiconductor layer so that any one of the source electrode and the drain electrode is electrically connected to the first electrode.

Description

Method of manufacturing thin film transistor substrate, and method of manufacturing organic light emitting display apparatus using the same

1 to 7 are cross-sectional views schematically illustrating a manufacturing process of a thin film transistor substrate according to an exemplary embodiment of the present invention.

8 to 10 are cross-sectional views schematically illustrating a manufacturing process of an organic light emitting display device according to another exemplary embodiment of the present invention.

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

101: support substrate 102: substrate

103: polymer layer 105: planarization film

120: thin film transistor 121: gate electrode

123: source electrode and drain electrode 125: gate insulating film

127; Semiconductor layer 131: first electrode

The present invention relates to a method of manufacturing a thin film transistor substrate and a method of manufacturing an organic light emitting display device using the same. More particularly, a display unit including a thin film transistor or the like is provided on a flexible substrate to implement a flexible display device. A method of manufacturing a thin film transistor substrate and an organic light emitting display device using the same.

Low-temperature polycrystalline silicon (LTPS) thin film transistors (TFTs), liquid crystal displays (LCDs) and organic light emitting displays (OLEDs) with them are currently digital. The market is expanding to include displays for cameras, video cameras, mobile information terminals (PDAs), and mobile devices such as mobile 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 reduced. It can be. Therefore, it is possible to reduce the pixel size, that is, high definition, so that the panel can be miniaturized, which is optimal for display for mobile devices.

The second characteristic is that the on-current current ratio of each transistor of n-channel and p-channel is balanced by factor 2, and the CMOS circuit can be configured. By using this, 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 first received therein and converted into a drive signal of a data wiring and a gate wiring connected to each pixel. The number of input pins on the panel can be reduced compared to the amorphous silicon thin film transistors that need to supply signals from the IC. 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 manufacturing using a conventional glass substrate and then making the glass substrate thin by a mechanical or chemical method 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 fabricated using such a plastic substrate at or below a heat resistance temperature, the coefficient of thermal expansion (linear expansion coefficient) of the plastic substrate is 50 ppm / 占 폚 or more. There was a problem that the expansion may cause a patterning error or disconnection of the wiring later.

SUMMARY OF THE INVENTION The present invention is to solve various problems including the above problems, and a method of manufacturing a thin film transistor substrate to implement a flexible display device by providing a display unit having a thin film transistor, etc. on the flexible substrate and using the same An object of the present invention is to provide a method of manufacturing an organic light emitting display device.

The present invention provides a method of forming a polymer layer on a support substrate, forming a first electrode on the polymer layer, forming a thin film transistor electrically connected to the first electrode, and covering the thin film transistor. Forming a planarization film on the planarization film, forming a substrate on the planarization film, and separating the support substrate by irradiating a laser beam to soften the polymer layer. It provides a manufacturing method.

According to another aspect of the present invention, the forming of the thin film transistor may include forming a first insulating film on the first electrode to expose a portion of the first electrode, and forming a semiconductor layer on the insulating film. Forming a source electrode and a drain electrode in contact with the semiconductor layer, wherein one of the source electrode and the drain electrode is electrically connected to the first electrode, and a gate insulating layer and a gate on the source electrode and the drain electrode It may be provided with the step of forming an electrode.

According to another feature of the invention, the polymer layer may be formed of polyimide

According to still another feature of the present invention, the substrate may be a plastic substrate.

According to still another feature of the present invention, the support substrate may be a glass substrate.

According to another feature of the invention, the laser beam may be irradiated through the support substrate.

According to another feature of the invention, after separating the support substrate, it may be further provided to remove the polymer layer on the first electrode.

According to another feature of the invention, after the step of removing the polymer layer, it may be further provided with the step of patterning the first electrode.

According to another feature of the present invention, the forming of the first electrode may be a step of forming a patterned first electrode on the polymer layer.

In order to achieve the above object, the present invention also provides a method of manufacturing a thin film transistor substrate, the method comprising the steps of: removing at least a portion of the polymer layer to expose at least a portion of the first electrode; Forming an intermediate layer including a light emitting layer on the exposed portion of the first electrode, and forming a second electrode around the intermediate layer to face the first electrode. It provides a manufacturing method.

According to another aspect of the present invention, removing at least a portion of the polymer layer is removing all of the polymer layer, and further comprising patterning the first electrode prior to forming the intermediate layer. I can do it

According to still another aspect of the present invention, the method may further include forming a pixel defining layer to expose at least a portion of the patterned first electrode between the patterning of the first electrode and the forming of the intermediate layer. can do

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

1 to 7 are cross-sectional views schematically illustrating a manufacturing process of a thin film transistor substrate according to an exemplary embodiment of the present invention.

First, as shown in FIG. 1, the polymer layer 103 is formed on the support substrate 101, and the first electrode 131 is formed on the polymer layer 103.

The support substrate 101 is formed of a material that can withstand high heat, such as a glass substrate or a metal substrate. In addition, even when the mechanical strength is sufficient and various elements or layers are formed thereon, it is preferable to use one formed of a material having no deformation.

The polymer layer 103 may be formed of various materials. As described below, it is preferable to use one formed of a material that is softened easily when the laser beam is irradiated. Examples of suitable materials for the polymer layer 103 include polyimide, polystyrene, and PMMA (poly (methyl methacrylate)). This will be described later.

The first electrode 131 may function as one electrode among the electrodes provided in the display device, and may be formed of various conductive materials. The first electrode 131 may be formed as a transparent electrode or may be formed as a reflective electrode according to a display element to be formed later. When used as a transparent electrode may be provided with ITO, IZO, ZnO or In ₂ O ₃ , when used as a reflective electrode Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr and compounds thereof After the reflection film is formed, or the like, ITO, IZO, ZnO, or In ₂ O ₃ can be formed thereon.

After forming the polymer layer 103 and the first electrode 131 on the support substrate 101 as described above, the thin film transistor 102 electrically connected to the first electrode 131 is shown in FIG. 3. And planarization film 105 is formed so as to cover the thin film transistor. At this time, if necessary, prior to forming the thin film transistor, as shown in FIG. 2, a step of forming the first insulating layer 129 on the first electrode 131 may be further exposed. have. This is to ensure that the thin film transistor is provided on the first electrode 131 in the drawing shown in FIG. 2. Of course, when the first electrode 131 is patterned in an island shape, unlike in FIGS. 1 and 2, the first electrode 131 and the thin film transistor may be formed on the same layer. The first insulating layer 129 may not be formed. Hereinafter, for convenience, a structure in which the thin film transistor is provided on the first electrode 131 and provided with the first insulating layer 129 will be described.

The first insulating layer 129 may be formed of an insulating material such as silicon oxide or silicon nitride, and of course, may also be formed of an insulating organic material. As shown in FIG. 2, the first insulating layer 129 has an opening 129a exposing at least a portion of the first electrode 131, whereby a thin film transistor formed later through the opening 129a is formed on the first electrode. To be electrically connected to 131.

3 illustrates a case in which a staggered thin film transistor is provided as an example of one thin film transistor. However, of course, a thin film transistor having a different structure may be provided. For example, as shown in FIG. 4, the position of the semiconductor layer 127 may be changed. Of course, other variations are possible. Hereinafter, a case in which the thin film transistor 120 of the type shown in FIG. 3 is provided for convenience.

When the staggered thin film transistor is provided as shown in FIG. 3, a source electrode and a drain electrode 123 are formed on the first insulating layer 129, and any one of the source electrode and the drain electrode 123 may be formed. 1 It is formed to be electrically connected to the first electrode 131 through the opening 129a of the insulating film 129. Thereafter, the semiconductor layer 127 is formed to be in contact with the source electrode and the drain electrode 123, and the gate insulating layer 125 and the gate electrode 121 are formed on the source electrode and the drain electrode 123.

The semiconductor layer 127 may be formed of polysilicon, and in this case, a predetermined region may be doped with impurities. Of course, the semiconductor layer 127 may be formed of amorphous silicon, not polysilicon, or may be formed of various organic semiconductor materials such as pentacene. When the semiconductor layer 127 is formed of polysilicon, amorphous silicon is formed and crystallized to polysilicon. As the supporting substrate 101, a substrate capable of withstanding the temperature in the crystallization step of amorphous silicon is used. This can prevent the deformation and the like from occurring.

The gate electrode 121, the source electrode, and the drain electrode 123 may be formed of various conductive materials. For example, it may be formed of a material such as Mg, Al, Ni, Cr, Mo, W, MoW or Au, and in this case, various modifications are possible, such as not only a single layer but also a plurality of layers. The gate insulating layer 125 may be formed of the material for the first insulating layer 129 described above.

After forming the thin film transistor 120 electrically connected to the first electrode 131 as described above, the planarization film 105 is formed to cover the thin film transistor 120.

Subsequently, as shown in FIG. 5, the substrate 102 is disposed on the planarization film 105, which becomes the substrate 102 provided with the thin film transistor 120. That is, after placing the substrate 102 on the planarization film 105, as shown in Fig. 6 by irradiating a laser beam to soften the polymer layer 103 to separate the support substrate 101, As shown in FIG. 7, a thin film transistor substrate having the thin film transistor 120 on the substrate 102 is obtained.

Accordingly, by using a substrate formed of a material having excellent flexible characteristics as the substrate 102 disposed on the planarization film 105, the flexible thin film transistor substrate can be realized. In this case, the substrate 102 having the flexible characteristic is disposed after the thin film transistor 120 is provided on the support substrate 101, and thus, the substrate 102 is formed of a material that can withstand high temperatures in a thin film transistor manufacturing process. The advantage is that there is no need. Therefore, a plastic substrate having excellent flexible characteristics may be used as the substrate 102, and a metal substrate may be used.

On the other hand, the laser beam is irradiated to separate the support substrate 101, and this laser beam serves to soften the polymer layer 103. That is, by irradiating a laser beam, the temperature of the polymer layer 103 reaches the glass transition temperature, that is, the temperature at which the polymer layer 103 changes from the hard glass state to the soft state, thereby supporting the substrate 101. To separate. For example, when the polymer layer 103 is formed of polyimide, since the glass transition temperature of the polyimide is about 300 ° C., the laser beam has a wavelength of about 248 nm and an intensity of about 0.07 J / cm ² to 5.0 J / cm ² . Irradiation of the polymer layer 103 can be softened to separate the support substrate 101. For forming a polymer layer 103 of PMMA is approximately 308nm wavelength and about 0.5J / cm ² to 3.0J / supported by softening the polymer layer (103) substrate by irradiating a laser beam having an intensity of ² cm ( 101) can be separated.

Meanwhile, the polymer layer 103 should not be softened during the process before the substrate 102 is disposed, such as the process of forming the semiconductor layer 127 from polysilicon. Therefore, it is preferable that the glass transition temperature of the polymer layer 103 is sufficiently high. For example, when the semiconductor layer 127 is formed of polysilicon, the temperature for changing amorphous silicon to polysilicon is about 300 ° C. The glass transition temperature of the polymer layer 103 is preferably about 300 ° C. or more so that the polymer layer 103 is not softened.

As described above, the support substrate 101 is separated by softening the polymer layer 103 by irradiating a laser beam, so that the glass substrate is supported by the support substrate 101 so that the laser beam can easily reach the polymer layer 103. And the laser beam can be irradiated through the glass support substrate 101. Of course, if the substrate 102 having the flexible characteristic has a transparent characteristic, the laser beam may be irradiated through the substrate 102, but in this case, the thin film transistor 120 may be applied before the laser beam reaches the polymer layer 103. Since the laser beam may be blocked by a component of the laser beam, the support substrate 101 may be formed of a material that passes the laser beam, and the laser beam may be irradiated through the laser beam.

On the other hand, in the case of softening the polymer layer 103 by irradiating a laser beam, the polymer layer 103 may also be removed together in the removal step of the supporting substrate 101, as shown in FIG. The 103 may not be removed or only a portion of the polymer layer 103 may be removed and some may remain. In the latter case, the step of removing the polymer layer 103 on the first electrode 131 after separating the support substrate 101 may be further roughened. This is done when it is necessary to pattern the first electrode into a specific shape, such as an island type. Of course, when forming the patterned first electrode 131 in forming the first electrode 131 on the first polymer layer 103, there is no need to go through this step.

By using the support substrate 101 and the polymer layer 103 in this manner, the thin film transistor substrate having the thin film transistor 120 on the flexible substrate 102 can be easily manufactured.

8 to 10 are cross-sectional views schematically illustrating a manufacturing process of an organic light emitting display device according to another exemplary embodiment of the present invention.

As described above, the thin film transistor substrate is manufactured, the first electrode 131 is patterned into an island shape as shown in FIG. 8, and then the first electrode 131 is patterned with an insulating material as shown in FIG. 9. The pixel defining layer 107 is formed to expose at least a portion of the pixel defining layer, and as shown in FIG. 10, an intermediate layer 133 including an emission layer is formed on the exposed portion of the first electrode 131. The organic light emitting display device may be manufactured by forming the second electrode 135 to face the first electrode 131 around the 133.

In FIG. 10, the intermediate layer 133 is shown to be patterned to correspond only to each subpixel, that is, each patterned first electrode 131, but this is illustrated as such for convenience in describing the configuration of the subpixel. 133 may be formed integrally with an intermediate layer of an adjacent subpixel. In addition, some layers of the intermediate layer 133 may be formed for each subpixel, and other layers may be integrally formed with an intermediate layer of an adjacent subpixel.

The intermediate layer 133 may be provided with low molecular weight or high molecular organic material. When using low molecular weight organic material, hole injection layer (HIL), hole transport layer (HTL), emissive layer (EML), electron transport layer (ETL), electron injection layer (EIL) The electron injection layer may be formed by stacking a single or 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), tris-8-hydroxyquinoline aluminum ( Alq3) can be used in various ways. These low molecular weight organic materials may be formed by a method such as vacuum deposition using masks.

In the case of the polymer organic material, the structure may include a hole transport layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transport layer, and poly-phenylenevinylene (PPV) and polyfluorene are used as the light emitting layer. Polymer organic materials such as (Polyfluorene) are used.

Like the first electrode 131, the second electrode 135 may be provided as a transparent electrode or a reflective electrode, and when used as a transparent electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Mg, and their A layer made of a compound and an auxiliary electrode or bus electrode line formed of a material for forming a transparent electrode such as ITO, IZO, ZnO, or In ₂ O ₃ may be provided on the layer. When used as a reflective electrode, Li, Ca, LiF / Ca, LiF / Al, Al, Mg, and compounds thereof are formed by full deposition.

On the other hand, as described in the method for manufacturing a thin film transistor substrate according to the above-described embodiment, when forming the first electrode 131 on the first polymer layer 103 to form the patterned first electrode 131, the supporting substrate Since the polymer layer 103 remaining on the first electrode 131 does not need to be removed after the 101 is separated, in this case, the polymer layer 103 may be used as the pixel defining layer.

That is, after separating the support substrate 101, at least a portion of the polymer layer 103 is removed to expose at least a portion of the first electrode 131, and a light emitting layer is included in the exposed portion of the first electrode 131. By forming the intermediate layer 133 and forming the second electrode 135 to face the first electrode 131 around the intermediate layer 133, a flexible organic light emitting display device can be easily manufactured.

According to the manufacturing method of the thin film transistor substrate of the present invention and the manufacturing method of the organic light emitting display device using the same as described above, on the flexible substrate without using a flexible substrate that can withstand the high temperature process in the process of forming the thin film transistor A thin film transistor substrate having a thin film transistor may be manufactured, and an organic light emitting display device having excellent flexible characteristics may be manufactured using the thin film transistor substrate.

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.

Claims (12)

Forming a polymer layer on a support substrate; Forming a first electrode on the polymer layer; Forming a thin film transistor electrically connected to the first electrode; Forming a planarization film to cover the thin film transistor; Disposing a substrate on the planarization film; And And separating the support substrate by irradiating a laser beam to soften the polymer layer. The method of claim 1, Forming the thin film transistor, Forming a first insulating film on the first electrode to expose a portion of the first electrode; Forming a semiconductor layer and a source electrode and a drain electrode in contact with the semiconductor layer, wherein one of the source electrode and the drain electrode is electrically connected to the first electrode; And And forming a gate insulating film and a gate electrode on the source electrode and the drain electrode. The method of claim 1, The polymer layer is a method of manufacturing a thin film transistor substrate, characterized in that formed of polyimide. The method of claim 1, The substrate is a method of manufacturing a thin film transistor substrate, characterized in that the plastic substrate. The method of claim 1, The support substrate is a method for manufacturing a thin film transistor substrate, characterized in that the glass substrate. The method of claim 1, And the laser beam is irradiated through the support substrate. The method of claim 1, After removing the support substrate, removing the polymer layer on the first electrode. The method of claim 7, wherein After the step of removing the polymer layer, further comprising the step of patterning the first electrode. The method of claim 1, The forming of the first electrode may include forming a patterned first electrode on the polymer layer. Manufacturing a thin film transistor substrate by the method of any one of claims 1 to 6; Removing at least a portion of the polymer layer to expose at least a portion of the first electrode; Forming an intermediate layer including a light emitting layer on the exposed portion of the first electrode; And And forming a second electrode to face the first electrode with respect to the intermediate layer. The method of claim 10, Removing at least a portion of the polymer layer may include removing all of the polymer layer, and further comprising patterning the first electrode prior to forming the intermediate layer. Manufacturing method. The method of claim 11, Manufacturing a pixel defining layer to expose at least a portion of the patterned first electrode between the patterning of the first electrode and the forming of the intermediate layer. Way.

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