Method of manufacturing a display device

Abstract

The present invention provides a method for manufacturing a display device, comprising: a step of preparing a substrate; a step of forming an amorphous silicon layer on the substrate; a step of cleaning the amorphous silicon layer with hydrofluoric acid; a step of crystallizing the amorphous silicon layer into a polycrystalline silicon layer; and a step of directly forming a metal layer on the polycrystalline silicon layer.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a display device, and more particularly to a method for manufacturing a display device with improved product reliability. Background Art

[0002] Generally, a display device such as an organic light emitting display device includes thin film transistors for driving respective pixels, and the thin film transistors include an active layer formed of polysilicon.

[0003] In order to form an active layer for a thin film transistor using a polysilicon film, there are a method of depositing amorphous silicon on a substrate and then crystallizing it, or a method of directly depositing polysilicon.

[0004] However, due to a plurality of protrusions formed during the process of crystallizing amorphous silicon into polysilicon, the dispersion of the thin film transistors increases, and problems such as afterimages may be recognized. Summary of the Invention

[0005] The present invention is for solving various problems including the above-described problems, and an object thereof is to reduce the dispersion of thin film transistors and prevent the recognition of afterimages, and at the same time provide a method for manufacturing a display device with improved reliability. However, these problems are examples and do not limit the scope of the present invention.

[0006] According to one aspect of the present invention, there is provided a method for manufacturing a display device, including: a step of preparing a substrate; a step of forming an amorphous silicon layer on the substrate; a step of cleaning the amorphous silicon layer using hydrofluoric acid; a step of crystallizing the cleaned amorphous silicon layer into a polysilicon layer; and a step of directly forming a metal layer on the polysilicon layer.

[0007] In the present embodiment, the metal layer may include at least one of aluminum and copper.

[0008] In the present embodiment, the metal layer may be formed on the polysilicon layer with a thickness of 100 Å to 700 Å .

[0009] In the present embodiment, in the step of crystallizing into the polysilicon layer, a laser beam may be irradiated onto each region of the substrate with different energy densities to perform crystallization.

[0010] In the present embodiment, the energy density of the laser beam may be 300 mJ / cm 2 to 500 mJ / cm 2 .

[0011] In this embodiment, it may be that the polysilicon layer includes protrusions less than 3 nm on the surface.

[0012] In this embodiment, it may be that after the step of cleaning the amorphous silicon layer with hydrofluoric acid, the step of cleaning the cleaned amorphous silicon layer with deionized water added with hydrogen is further included.

[0013] In this embodiment, it may be that the metal layer includes at least one of aluminum and copper.

[0014] In this embodiment, it may be that the step of irradiating light onto the metal layer is further included.

[0015] In this embodiment, it may be that the step of cleaning the amorphous silicon layer with hydrofluoric acid is a step of spraying the hydrofluoric acid onto the amorphous silicon layer to remove the oxide film formed on the surface of the amorphous silicon layer.

[0016] In this embodiment, it may be that the hydrofluoric acid includes about 0.5% hydrogen fluoride.

[0017] In this embodiment, it may be that between the step of preparing the substrate and the step of forming the amorphous silicon layer on the substrate, the step of forming a buffer layer on the substrate is further included.

[0018] According to another aspect of the present invention, there is provided a method for manufacturing a display device, including: a step of preparing a substrate defined with a first region and a second region; a step of forming an amorphous silicon layer on the substrate; a step of cleaning the amorphous silicon layer with hydrofluoric acid; a step of irradiating laser beams with different energy densities onto the first region and the second region respectively to crystallize the cleaned amorphous silicon layer into a polysilicon layer; and a step of directly forming a metal layer on the polysilicon layer.

[0019] In this embodiment, it may be that the metal layer includes at least one of aluminum and copper.

[0020] In this embodiment, it may be that the metal layer is formed on the polysilicon layer with a thickness of 100 Å to 700 Å .

[0021] In this embodiment, it may be that the polysilicon layer includes protrusions less than 3 nm on the surface.

[0022] In this embodiment, it may be that the step of irradiating light onto the metal layer is further included.

[0023] In this embodiment, it may be that after the step of cleaning the amorphous silicon layer with hydrofluoric acid, it further includes a step of cleaning the cleaned amorphous silicon layer with deionized water added with hydrogen.

[0024] In this embodiment, it may be that the metal layer includes at least one of aluminum and copper.

[0025] In this embodiment, it may be that between the step of preparing the substrate and the step of forming the amorphous silicon layer on the substrate, it further includes a step of forming a buffer layer on the substrate.

[0026] Other aspects, features, and advantages other than the above will become apparent through the following detailed description, claims, and drawings.

[0027] (Advantages of the Invention)

[0028] According to an embodiment of the present invention configured as described above, the dispersion of thin film transistors can be reduced and the occurrence of afterimages can be prevented, and at the same time, a display device with improved product reliability can be realized. Of course, the scope of the present invention is not limited by these effects. Description of the Drawings

[0029] Figure 1 It is a plan view schematically showing a manufacturing method of a display device according to an embodiment of the present invention.

[0030] Figures 2 to 8 It is a cross-sectional view schematically showing a manufacturing method of a display device according to an embodiment of the present invention.

[0031] Figure 9 It is a perspective view schematically showing a display device according to an embodiment of the present invention.

[0032] Figure 10 It is a cross-sectional view schematically showing a display device according to an embodiment of the present invention.

[0033] (Reference Signs)

[0034] 1: Display device; 100: Substrate; 120: Amorphous silicon layer; 160: Polysilicon layer; 170: Metal layer. Detailed Description of the Invention

[0035] The present invention can have various transformations and various embodiments. Specific embodiments are illustrated in the drawings and described in detail. Referring to each embodiment described in detail below, the effects, features, and methods for achieving these effects and features of the present invention will become clear. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various ways. Figure 1 The effects, features, and methods for achieving these effects and features of the present invention will become clear by referring to each embodiment described in detail below. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various ways.

[0036] In the following embodiments, terms such as first, second, etc. are not restrictive terms and are used to distinguish one component from other components.

[0037] In the following embodiments, singular expressions include plural expressions when there is no clear contrary meaning in the text.

[0038] In the following embodiments, terms such as "including" or "having" should be understood as referring to the presence of the features or components described in the specification, and do not preclude the possibility of adding one or more other features or components in advance.

[0039] In the following embodiments, when a part such as a film, a region, or a component is located on or above another part, it includes not only the case where it is directly located on the other part, but also the case where there are other films, regions, components, etc. therebetween.

[0040] In the drawings, for ease of explanation, the sizes of the respective components may be enlarged or reduced. For example, the sizes and thicknesses of the illustrated components are shown for ease of explanation, and the present invention is not necessarily limited to the illustrated cases.

[0041] In this specification, "A and / or B" means A, or B, or A and B. In addition, in this specification, "at least one of A and B" means A, or B, or A and B.

[0042] In the following embodiments, the wiring "extends in the first direction or the second direction" not only refers to the case where it extends in a straight shape, but also includes the case where it extends in a meandering shape or a curved shape along the first direction or the second direction.

[0043] In the following respective embodiments, "on the plane" refers to the case of looking down on the object part, and "in the cross-section" refers to the case of observing a cross-section obtained by vertically intercepting the object part from the side. In the following respective embodiments, "overlap" includes "overlap on the plane" and "overlap in the cross-section".

[0044] Hereinafter, with reference to the drawings, each embodiment of the present invention will be described in detail. When describing the specification with reference to the drawings, the same reference numerals are given to the same or corresponding components.

[0045] Figure 1 It is a plan view schematically showing a manufacturing method of a display device according to an embodiment of the present invention, Figures 2 to 8 It is a cross-sectional view schematically showing a manufacturing method of a display device according to an embodiment of the present invention.

[0046] Hereinafter, with reference to Figures 1 to 8 to sequentially describe the manufacturing method of the display device.

[0047] Referring to Figures 1 to 8 , a method of manufacturing a display device according to an embodiment may include: a step of preparing a substrate 100; a step of forming an amorphous silicon layer 120 on the substrate 100; a step of cleaning the amorphous silicon layer 120 with hydrofluoric acid 130; a step of crystallizing the cleaned amorphous silicon layer 120 into a polysilicon layer 160; and a step of directly forming a metal layer 170 on the polysilicon layer 160.

[0048] In addition, after the step of preparing the substrate 100, a step of forming a buffer layer 110 on the substrate 100 may further be included, and after the step of cleaning the amorphous silicon layer 120 with hydrofluoric acid 130, a step of cleaning the cleaned amorphous silicon layer 120 with deionized water 140 added with hydrogen may further be included.

[0049] Referring to Figure 1 , first, the step of preparing the substrate 100 may be performed. A plurality of regions may be defined in the substrate 100. As an embodiment, a first region 1A, a second region 2A, a third region 3A, and a fourth region 4A may be defined in the substrate 100. However, although Figure 1 shows a case where four regions are defined in the substrate 100, this is for convenience of explanation, and the present invention is not limited thereto. For example, in addition to the first region 1A, the second region 2A, the third region 3A, and the fourth region 4A, the substrate 100 may further define a plurality of regions such as a fifth region and a sixth region.

[0050] The substrate 100 may include glass, quartz, ceramics, etc. In addition, the substrate 100 may include a polymer resin such as polyethersulfone, polyacrylate, polyether imide, Polyethylene naphthalate, Polyethyleneterephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, or cellulose acetatepropionate. The substrate 100 including the polymer resin may have characteristics of flexibility, rollability, or bendability. The substrate 100 may be a multilayer structure including a layer having the aforementioned polymer resin and an inorganic layer (not shown).

[0051] Referring to Figure 2, after the step of preparing the substrate 100, the step of forming the buffer layer 110 on the substrate 100 can be performed.

[0052] The buffer layer 110 can be located on the substrate 100 to provide a flat surface on the substrate 100. The buffer layer 110 can include inorganic substances such as oxides or nitrides, organic substances, or organic-inorganic composites, and can be formed by a single-layer or multi-layer structure of inorganic substances and organic substances. As an embodiment, silicon oxide (SiO2) or silicon nitride (SiN X ) can be provided.

[0053] Refer to Figure 3 and Figure 4 , after the step of forming the buffer layer 110 on the substrate 100, the step of forming the amorphous silicon layer 120 on the buffer layer 110 can be performed.

[0054] The amorphous silicon layer 120 can be formed on the buffer layer 110. The amorphous silicon layer 120 can be formed by methods such as low-pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), plasma-enhanced chemical vapor deposition (PECVD), sputtering, vacuum deposition, etc.

[0055] Refer to Figure 4 , when the amorphous silicon layer 120 is formed on the buffer layer 110, an oxide film 125 can be naturally formed on the surface 121 of the amorphous silicon layer 120. When the oxide film 125 exists on the surface 121 of the amorphous silicon layer 120, during the process of crystallizing the amorphous silicon layer 120 into the polysilicon layer 160 described later, relatively large-thickness protrusions may be formed on the surface of the polysilicon layer 160. Therefore, before crystallizing the amorphous silicon layer 120 into the polysilicon layer 160 described later, the process of removing the oxide film 125 formed on the amorphous silicon layer 120 can be performed.

[0056] Refer to Figure 5 , after the step of forming the amorphous silicon layer 120 on the buffer layer 110, the step of cleaning the amorphous silicon layer 120 with hydrofluoric acid can be performed.

[0057] As described above, when the oxide film 125 exists on the surface 121 of the amorphous silicon layer 120, during the process of crystallizing the amorphous silicon layer 120 into the polysilicon layer 160 described later, relatively large-thickness protrusions may be formed on the surface of the polysilicon layer 160. Therefore, before performing the crystallization process, the process of removing the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120 can be performed first.

[0058] When using water or ozone (O3) to remove the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120, there may be a problem that the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120 cannot be completely removed and a residual film or the like remains.

[0059] Therefore, in the manufacturing method of a display device according to an embodiment, hydrofluoric acid 130 can be used to clean the amorphous silicon layer 120. More specifically, hydrofluoric acid 130 can be sprayed onto the amorphous silicon layer 120 to remove the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120.

[0060] Hydrofluoric acid 130 can be an aqueous solution in which hydrogen fluoride (HF) is dissolved. As an embodiment, hydrofluoric acid 130 can include about 0.3% hydrogen fluoride, and can also be deformed into various situations, such as including about 1% hydrogen fluoride, or including about 0.7% hydrogen fluoride, etc. For example, hydrofluoric acid 130 can include about 0.5% hydrogen fluoride.

[0061] By using hydrofluoric acid 130 including about 0.5% hydrogen fluoride to clean the amorphous silicon layer 120, the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120 can be removed.

[0062] When the cleaning time of the amorphous silicon layer 120 is about shorter than 40 seconds, the oxide film 125 formed on the surface 121 of the amorphous silicon layer 120 may not be sufficiently removed. When the cleaning time of the amorphous silicon layer 120 is about longer than 54 seconds, the amorphous silicon layer 120 may be affected by hydrofluoric acid 130. Therefore, hydrofluoric acid 130 can be used to clean the amorphous silicon layer 120 during about 40 seconds to about 54 seconds.

[0063] Refer to Figure 6 , after the step of cleaning the amorphous silicon layer 120 with hydrofluoric acid 130, a step of cleaning the cleaned amorphous silicon layer 120 with deionized water 140 added with hydrogen can also be performed.

[0064] When cleaning the amorphous silicon layer 120 with deionized water without added hydrogen, the oxygen contained in the deionized water may remain on the amorphous silicon layer 120, and circular defects may be caused due to the oxygen remaining on the amorphous silicon layer 120. However, in the manufacturing method of a display device according to an embodiment of the present invention, deionized water 140 added with hydrogen is used to clean the amorphous silicon layer 120, thereby preventing the occurrence of the circular defects.

[0065] The amorphous silicon layer 120 can be cleaned using deionized water 140 added with hydrogen. As an example, about 2.0 ppm of hydrogen can be added to the deionized water 140, and it can also be varied in various cases, such as adding about 0.5 ppm of hydrogen, or adding about 1.5 ppm of hydrogen, etc. For example, about 1.0 ppm of hydrogen can be added to the deionized water 140.

[0066] As an example, the deionized water 140 added with hydrogen can be dripped in a free-fall manner to clean the amorphous silicon layer 120, or the deionized water 140 added with hydrogen can be spray-jet to clean the amorphous silicon layer 120, or the deionized water 140 added with hydrogen can be dripped in a free-fall manner but vibration can be imparted to the deionized water 140 added with hydrogen using mega sonic to clean the amorphous silicon layer 120.

[0067] Referring to Figures 7a to 7d , after the step of cleaning the cleaned amorphous silicon layer 120 using the deionized water 140 added with hydrogen, the step of crystallizing the cleaned amorphous silicon layer 120 into a polycrystalline silicon layer 160 can be performed.

[0068] A laser beam can be irradiated to the amorphous silicon layer 120 to form a polycrystalline silicon layer 160. The laser 150 can intermittently generate a laser beam and irradiate it to the amorphous silicon layer 120. For example, the laser 150 can be an excimer laser that generates a single-wavelength, high-output, and high-efficiency laser beam. The excimer laser can include, for example, inert gases, inert gas halides, mercury halides, inert gas oxides, and polyatomic excimers. For example, the inert gas is Ar2, K r2 , Xe2, etc., the inert gas halide is ArF, ArCl, KrF, KrCl, XeF, XeCl, etc., the mercury halide is HgCl, HgBr, HgI, etc., the inert gas oxide is ArO, KrO, XeO, etc., and the polyatomic excimer is Kr2F, Xe2F, etc.

[0069] In the step of crystallizing the amorphous silicon layer 120 into a polycrystalline silicon layer 160, the energy density of the laser beam can be 300 mJ / cm 2 to 500 mJ / cm 2 , and it can also be varied in various cases, such as being 350 mJ / cm 2 to 450 mJ / cm 2 , or 400 mJ / cm 2 to 500 mJ / cm 2 etc. For example, the energy density of the laser beam can be 430 mJ / cm 2 to 500 mJ / cm 2 .

[0070] When a laser beam is irradiated onto the amorphous silicon layer 120 in a solid state, the amorphous silicon layer 120 can absorb heat and change to a liquid state, and then dissipate heat and change back to a solid state. At this time, crystallization grows from the crystallization seeds, and thus crystal grains can be formed. When there is a difference in the cooling rate during the process of the amorphous silicon layer 120 changing from a liquid state to a solid state, the crystal grains can grow from the region with a fast cooling rate toward the region with a slow cooling rate, and grain boundaries can be formed in the region with a slow cooling rate.

[0071] On the surface of the polysilicon layer 160 that has undergone the crystallization process, protrusions 161 may be formed at the grain boundaries. It is possible that the amorphous silicon layer 120 melted by the laser beam recrystallizes with the crystal grains as the center, and protrusions 161 are formed at the grain boundaries.

[0072] The protrusions 161 can protrude upward from the surface of the polysilicon layer 160 and can have a shape with a sharp end. The effective value of the surface roughness of the polysilicon layer 160 can be about 3 nm or less. The protrusions 161 can have a thickness corresponding to the distance from the surface of the polysilicon layer 160 to the end of the protrusions 161. For example, the polysilicon layer 160 can include a plurality of protrusions 161 with a height of 3 nm or less on the surface.

[0073] By performing a cleaning process using hydrofluoric acid 130 and a cleaning process using deionized water 140 added with hydrogen before the crystallization process, the thickness of the protrusions 161 formed on the surface of the polysilicon layer 160 can be reduced, and a polysilicon layer 160 with a relatively small surface roughness can be formed.

[0074] In the step of crystallizing the amorphous silicon layer 120 into the polysilicon layer 160, laser beams can be irradiated onto each region of the substrate 100 with different energy densities, so that the cleaned amorphous silicon layer 120 is crystallized into the polysilicon layer 160.

[0075] More specifically, laser beams can be irradiated onto the first region 1A, the second region 2A, the third region 3A, and the fourth region 4A defined on the substrate 100 with different energy densities, so that the cleaned amorphous silicon layer 120 is crystallized into the polysilicon layer 160.

[0076] As Figure 7a shown, a first laser beam 151 with a first energy density can be irradiated onto the first region 1A of the substrate 100, so that the amorphous silicon layer 120 disposed on the first region 1A of the substrate 100 is crystallized into a first polysilicon layer 160a. At this time, a plurality of first protrusions 161a can be formed on the surface of the first polysilicon layer 160a.

[0077] AsFigure 7b As shown, a second laser beam 152 having a second energy density can be irradiated onto the second region 2A of the substrate 100, so that the amorphous silicon layer 120 disposed on the second region 2A of the substrate 100 is crystallized into a second polysilicon layer 160b. At this time, a plurality of second protrusions 161b can be formed on the surface of the second polysilicon layer 160b.

[0078] As Figure 7c shown, a third laser beam 153 having a third energy density can be irradiated onto the third region 3A of the substrate 100, so that the amorphous silicon layer 120 disposed on the third region 3A of the substrate 100 is crystallized into a third polysilicon layer 160c. At this time, a plurality of third protrusions 161c can be formed on the surface of the third polysilicon layer 160c.

[0079] As Figure 7d shown, a fourth laser beam 154 having a fourth energy density can be irradiated onto the fourth region 4A of the substrate 100, so that the amorphous silicon layer 120 disposed on the fourth region 4A of the substrate 100 is crystallized into a fourth polysilicon layer 160d. At this time, a plurality of fourth protrusions 161d can be formed on the surface of the fourth polysilicon layer 160d.

[0080] In addition, in the case where the substrate 100 is defined with multiple regions such as a fifth region, a sixth region, etc. in addition to the first region 1A, the second region 2A, the third region 3A, and the fourth region 4A, laser beams with different energy densities can be irradiated onto each region respectively.

[0081] Since laser beams with different energy densities are irradiated onto each region of the substrate 100 respectively, the respective protrusions 161 formed on the surface of the polysilicon layer 160 in each region of the substrate 100 can have different arrangements. For example, the arrangement of the first protrusions 161a of the first polysilicon layer 160a on the first region 1A of the substrate 100 and the arrangement of the second protrusions 161b of the second polysilicon layer 160b on the second region 2A of the substrate 100 can be different from each other.

[0082] Referring Figure 8 , after the step of crystallizing the cleaned amorphous silicon layer 120 into the polysilicon layer 160, a step of directly forming a metal layer 170 on the polysilicon layer 160 can also be performed.

[0083] In addition, as an embodiment, after the step of directly forming a metal layer 170 on the polysilicon layer 160, it can further include a step of irradiating light onto the metal layer 170 and a step of selecting the optimal energy density of the laser using the light reflected from the metal layer 170.

[0084] According to an embodiment of the present invention, by performing a cleaning process using hydrofluoric acid 130 and a cleaning process using deionized water 140 added with hydrogen before the crystallization process, it is possible to reduce the thickness of the protrusions 161 formed on the surface of the polysilicon layer 160, and a polysilicon layer 160 with a relatively small surface roughness can be formed.

[0085] Since laser beams with different energy densities are irradiated onto respective regions of the substrate 100, the respective protrusions 161 formed on the surface of the polysilicon layer 160 in the respective regions of the substrate 100 can have different arrangements. If light is irradiated onto the surface of the polysilicon layer 160 including a plurality of protrusions 161, vertical line stains may be recognized due to the arrangement of the plurality of protrusions 161 formed on the surface of the polysilicon layer 160. The vertical line stains can cause defects in the display device. Therefore, it is preferable to crystallize amorphous silicon into polysilicon using the energy density of a laser that does not recognize the vertical line stains.

[0086] However, when selecting the optimal energy density of the laser using the light reflected from the polysilicon layer 160 irradiated with light, due to the reduced thickness of the protrusions 161, the scattering of the reflected light increases, so it is difficult to select the optimal energy density of the laser.

[0087] Therefore, in the present invention, by directly forming a metal layer 170 including a metal with a high reflectivity on the polysilicon layer 160, it is possible to easily select the optimal energy density of the laser.

[0088] The metal layer 170 can be directly formed on the polysilicon layer 160. The metal layer 170 can include a metal with a high reflectivity. For example, the metal layer 170 can include at least one of aluminum and copper.

[0089] The metal layer 170 can have a first thickness t1 from the upper surface of the polysilicon layer 160. As an embodiment, the metal layer 170 can be formed with a thickness of 1 angstrom to 700 angstroms from the upper surface of the polysilicon layer 160, and can also be deformed into various cases. For example, it can be formed with a thickness of 50 angstroms to 500 angstroms or with a thickness of 100 angstroms to 400 angstroms and so on. For example, the metal layer 170 can be formed with a thickness of 100 angstroms to 300 angstroms from the upper surface of the polysilicon layer 160.

[0090] Light can be irradiated onto the metal layer 170 including aluminum or copper, and the reflected light from the metal layer 170 can be used to select the optimal energy density of the laser. At this time, the reflected light from the metal layer 170 can be used to select the optimal energy density of the laser by various methods such as macroscopic (Macro) inspection or optical sensors.

[0091] According to the optimal energy density of the laser selected by the above method, it can be applied to the process of mass-producing by crystallizing the amorphous silicon layer.

[0092] Figure 9 FIG. is a perspective view schematically showing a display device according to an embodiment of the present invention, Figure 10 FIG. is a cross-sectional view schematically showing a display device according to an embodiment of the present invention.

[0093] Referring to Figure 9 , the display device 1 may include a display area DA and a non-display area NDA disposed around the display area DA. The non-display area NDA may surround the display area DA. The display device 1 may provide an image using light emitted from a plurality of pixels P disposed in the display area DA, and the non-display area NDA may be an area where no image is displayed.

[0094] Hereinafter, the display device 1 according to an embodiment of the present invention will be described by taking an organic light-emitting display device as an example, but the display device of the present invention is not limited thereto. As an embodiment, the display device 1 of the present invention may be a display device such as an inorganic light-emitting display device (Inorganic Light Emitting Display or inorganic EL Display) or a quantum dot light-emitting display device (Quantum dot Light Emitting Display). For example, the light-emitting layer as a display element included in the display device 1 may include an organic substance, or an inorganic substance, or a quantum dot, or an organic substance and a quantum dot, or an inorganic substance and a quantum dot.

[0095] In Figure 9 a display device 1 having a flat display surface is shown, but the present invention is not limited thereto. As an embodiment, the display device 1 may include a three-dimensional display surface or a curved display surface.

[0096] When the display device 1 includes a three-dimensional display surface, the display device 1 may include a plurality of display areas indicating different directions from each other. For example, it may include a polygonal columnar display surface. As an embodiment, when the display device 1 includes a curved display surface, the display device 1 may be implemented in various forms such as a flexible, foldable, or rollable display device.

[0097] In Figure 9The display device 1 applicable to a portable telephone terminal is shown. Although not illustrated, electronic modules, camera modules, power modules, etc. mounted on the main board can be configured together with the display device 1 in a bracket / case, etc., thereby constituting a portable telephone terminal. In particular, the display device 1 according to the present invention can be applied to medium and small-sized electronic devices such as tablets, car navigation systems, game consoles, smart watches, etc., as well as large electronic devices such as televisions and monitors.

[0098] In Figure 9 the case where the display area DA of the display device 1 is rectangular is shown, but the shape of the display area DA can be a polygon such as a circle, an ellipse, a triangle, or a pentagon.

[0099] The display device 1 includes a plurality of pixels P disposed in the display area DA. Each of the plurality of pixels P can include an Organic Light-Emitting Diode (OLED). Each of the plurality of pixels P can emit light such as red, green, blue, or white through the organic light-emitting diode OLED. In this specification, the pixel P can be understood as a pixel that emits light of any one of red, green, blue, or white as described above.

[0100] Referring to Figure 10 , display elements can be disposed on the substrate 100. The display elements can include thin film transistors (TFTs) and organic light-emitting diodes (OLEDs).

[0101] The substrate 100 can include glass or a polymer resin. The polymer resin can include polyethersulfone, polyacrylate, polyether imide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, or cellulose acetate propionate, etc. The substrate 100 including the polymer resin can have the characteristics of flexibility, rollability, or bendability. The substrate 100 can be a multilayer structure including a layer containing the aforementioned polymer resin and an inorganic layer (not illustrated).

[0102] A buffer layer 101 can be disposed on the substrate 100. The buffer layer 101 can be located on the substrate 100 to reduce or block the penetration of foreign substances, moisture, or external air from the lower part of the substrate 100, and can provide a flat surface on the substrate 100. The buffer layer 101 can include inorganic substances such as oxides or nitrides, organic substances, or organic-inorganic composites, and can be formed of a single layer or multiple layers of inorganic substances and organic substances.

[0103] A thin film transistor TFT can be disposed on the buffer layer 101. The thin film transistor TFT can include a semiconductor layer 134, a gate electrode 136 overlapping the semiconductor layer 134, and a connection electrode electrically connected to the semiconductor layer 134. The thin film transistor TFT can be connected to an organic light emitting diode OLED to drive the organic light emitting diode OLED.

[0104] The semiconductor layer 134 can be disposed on the buffer layer 101 and include a channel region 131 overlapping the gate electrode 136, and a source region 132 and a drain region 133 disposed on both sides of the channel region 131 and containing impurities with a higher concentration than the channel region 131. Here, the impurities can include N-type impurities or P-type impurities. The source region 132 and the drain region 133 can be electrically connected to the connection electrode.

[0105] The semiconductor layer 134 can include polycrystalline silicon obtained by crystallizing amorphous silicon (a-Si). For example, the semiconductor layer 134 can include polycrystalline silicon formed using the optimal energy density of a laser selected by the manufacturing method.

[0106] A first insulating layer 103 can be disposed on the semiconductor layer 134. The first insulating layer 103 can include at least one inorganic insulator selected from the group consisting of silicon oxide (SiO2), silicon nitride (SiN x )), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO2). The first insulating layer 103 can be a single layer or multiple layers including the aforementioned inorganic insulator.

[0107] A gate electrode 136 can be disposed on the first insulating layer 103. The gate electrode 136 can be formed of one or more metals selected from aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and copper (Cu) as a single layer or multiple layers. The gate electrode 136 can be connected to a gate line that applies an electrical signal to the gate electrode 136.

[0108] A second insulating layer 105 may be disposed on the gate electrode 136. The second insulating layer 105 may include at least one inorganic insulator selected from the group consisting of silicon oxide (SiO2), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO2). The second insulating layer 105 may be a single layer or multiple layers including the aforementioned inorganic insulator.

[0109] A storage capacitor Cst may be disposed on the first insulating layer 103. The storage capacitor Cst may include a lower electrode 144 and an upper electrode 146 overlapping the lower electrode 144. The lower electrode 144 and the upper electrode 146 of the storage capacitor Cst may be overlapped with the second insulating layer 105 interposed therebetween.

[0110] The lower electrode 144 of the storage capacitor Cst may overlap with the gate electrode 136 of the thin film transistor TFT, and the lower electrode 144 of the storage capacitor Cst may be configured to be integral with the gate electrode 136 of the thin film transistor TFT. As an embodiment, the storage capacitor Cst may not overlap with the thin film transistor TFT, and the lower electrode 144 of the storage capacitor Cst may be a component independent of the gate electrode 136 of the thin film transistor TFT.

[0111] The upper electrode 146 of the storage capacitor Cst may include aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and / or copper (Cu), and may be a single layer or multiple layers of the aforementioned substances.

[0112] A third insulating layer 107 may be disposed on the upper electrode 146 of the storage capacitor Cst. The third insulating layer 107 may include at least one inorganic insulator selected from the group consisting of silicon oxide (SiO2), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO2). The third insulating layer 107 may be a single layer or multiple layers including the aforementioned inorganic insulator.

[0113] On the third insulating layer 107, a source electrode 137 and a drain electrode 138, which are connection electrodes, can be disposed. The source electrode 137 and the drain electrode 138 can include a conductive material containing molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), etc., and can be formed of a multi-layer or a single layer including the above materials. The source electrode 137 and the drain electrode 138 can be formed of a multi-layer structure of Ti / Al / Ti.

[0114] On the source electrode 137 and the drain electrode 138, a first planarization layer 111 can be disposed. The first planarization layer 111 can be a layer formed of a film of an organic material or an inorganic material and formed into a single layer or a multi-layer. As an embodiment, the first planarization layer 111 can include general polymers such as benzocyclobutene (BCB), polyimide (PI), hexamethyldisiloxane (HMDSO), poly(methyl methacrylate) (PMMA), or polystyrene (PS), polymer derivatives having a phenolic group, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluorine polymers, parylene polymers, vinyl alcohol polymers, and mixtures thereof. On the other hand, the first planarization layer 111 can include silicon oxide (SiO2), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnO2), etc. After forming the first planarization layer 111, chemical-mechanical polishing can be performed to provide a flat upper surface.

[0115] On the first planarization layer 111, a contact metal layer CM can be disposed. The contact metal layer CM can include aluminum (Al), copper (Cu), titanium (Ti), etc., and can be formed of a multi-layer or a single layer. The contact metal layer CM can be formed of a multi-layer structure of Ti / Al / Ti.

[0116] A second planarization layer 113 may be disposed on the contact metal layer CM. The second planarization layer 113 may be a film formed of an organic material or an inorganic material and formed as a single layer or multiple layers. As an example, the second planarization layer 113 may include general polymers such as Benzocyclobutene (BCB), polyimide (PI), Hexamethyldisiloxane (HMDSO), Poly(methyl methacrylate) (PMMA), or Polystyrene (PS), polymer derivatives having phenolic groups, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluorine polymers, parylene polymers, vinyl alcohol polymers, and mixtures thereof. On the other hand, the second planarization layer 113 may include silicon oxide (SiO2), silicon nitride (SiN x ), silicon oxynitride (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), or zinc oxide (ZnO2). After forming the second planarization layer 113, chemical-mechanical polishing may be performed to provide a flat upper surface. As an example, the second planarization layer 113 may be omitted.

[0117] An organic light-emitting diode OLED including a pixel electrode 210, an intermediate layer 220, and a counter electrode 230 may be disposed on the second planarization layer 113. The pixel electrode 210 may be electrically connected to the contact metal layer CM through a contact hole penetrating the second planarization layer 113, and the contact metal layer CM may be electrically connected to the source electrode 137 and the drain electrode 138, which are connection electrodes of the thin-film transistor TFT, through a contact hole penetrating the first planarization layer 111, so that the organic light-emitting diode OLED may be electrically connected to the thin-film transistor TFT.

[0118] The pixel electrode 210 may be disposed on the second planarization layer 113. The pixel electrode 210 may be a (semi) transparent electrode or a reflective electrode. The pixel electrode 210 may include a reflective film and a transparent or semi-transparent electrode layer formed on the reflective film. The reflective film may be formed of aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), copper (Cu), and their compounds. The transparent or semi-transparent electrode layer may include at least one selected from the group including indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In2O3), indium gallium oxide (IGO), and aluminum zinc oxide (AZO). The pixel electrode 210 may have a structure of ITO / Ag / ITO laminated.

[0119] The pixel defining film 180 may be disposed on the second planarization layer 113. The pixel defining film 180 may have an opening exposing at least a part of the pixel electrode 210. The region exposed through the opening of the pixel defining film 180 may be defined as a light emitting region EA. The periphery of the light emitting region EA is a non-light emitting region NEA, and the non-light emitting region NEA may surround the light emitting region EA. That is, the display region DA may include a plurality of light emitting regions EA and non-light emitting regions NEA surrounding the plurality of light emitting regions EA. The pixel defining film 180 may increase the distance from the counter electrode 230 above the pixel electrode 210, thereby preventing the occurrence of an arc or the like at the edge position of the pixel electrode 210. The pixel defining film 180 may be formed by a method such as spin coating using an organic insulating material such as polyimide, polyamide, acrylic resin, benzocyclobutene, HMDSO (hexamethyldisiloxane), and phenolic resin.

[0120] The intermediate layer 220 may be disposed on the pixel electrode 210 at least a part of which is exposed through the pixel defining film 180. The intermediate layer 220 may include a light emitting layer 220b, and a first functional layer 220a and a second functional layer 220c may be selectively disposed below and above the light emitting layer 220b.

[0121] As an embodiment, the intermediate layer 220 may be formed on the pixel electrode 210 exposed through at least a part of the pixel defining film 180. More specifically, the light-emitting layer 220b of the intermediate layer 220 may be formed on the pixel electrode 210 exposed through at least a part of the pixel defining film 180.

[0122] The first functional layer 220a may include a hole injection layer (HIL: hole injection layer) and / or a hole transport layer (HTL: hole transport layer), and the second functional layer 220c may include an electron transport layer (ETL: electron transport layer) and / or an electron injection layer (EIL: electron injection layer).

[0123] The light-emitting layer 220b may include an organic substance containing a fluorescent or phosphorescent material that emits red, green, blue, or white light. The light-emitting layer 220b may be a low-molecular organic substance or a high-molecular organic substance.

[0124] In the case where the light-emitting layer 220b includes a low-molecular organic substance, the intermediate layer 220 may have a structure in which a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, etc. are stacked in a single or composite structure. Examples of the low-molecular organic substance may include various organic substances such as copper phthalocyanine (CuPc: copper phthalocyanine), N,N’-di(naphthalene-1-yl)-N,N’-diphenyl-benzidine (NPB), tris(8-hydroxyquinoline) aluminum (Alq3), etc. Such layers may be formed by a vacuum deposition method.

[0125] In the case where the light-emitting layer 220b includes a high-molecular organic substance, the intermediate layer 220 may generally have a structure including a hole transport layer and a light-emitting layer. At this time, the hole transport layer may include PEDOT, and the light-emitting layer may include high-molecular substances such as a PPV (Poly-Phenylene vinylene) system and a polyfluorene system. Such a light-emitting layer may be formed by a method such as screen printing, inkjet printing, or laser induced thermal imaging (LITI: Laser induced thermal imaging).

[0126] The counter electrode 230 can be disposed on the intermediate layer 220. The counter electrode 230 can be disposed on the intermediate layer 220 and configured to cover the entire shape of the intermediate layer 220. The counter electrode 230 can be disposed on the upper portion of the display area DA and configured to cover the entire shape of the display area DA. That is, the counter electrode 230 can be integrally formed on the entire display panel using an open mask so as to cover the plurality of pixels P disposed in the display area DA.

[0127] The counter electrode 230 can include a conductive material having a low work function. For example, the counter electrode 230 can include a (semi) transparent layer containing silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), or an alloy thereof. Alternatively, the counter electrode 230 can further include a layer such as ITO, IZO, ZnO, or In2O3 on the (semi) transparent layer including the foregoing materials.

[0128] The present invention has been described with reference to the illustrated embodiments, but these are merely examples, and those skilled in the art should understand that various modifications and equivalent other embodiments can be achieved therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical idea of the claims.

Claims

1. A manufacturing method of a display device, comprising: A step of preparing a substrate; A step of forming an amorphous silicon layer on the substrate; A step of cleaning the amorphous silicon layer with hydrofluoric acid; A step of irradiating a laser beam on the cleaned amorphous silicon layer to crystallize it into a polysilicon layer; A step of directly forming a metal layer on the polysilicon layer, A step of irradiating light on the metal layer, and A step of selecting an optimal energy density of the laser beam by using light reflected from the metal layer.

2. The manufacturing method of the display device according to claim 1, wherein The metal layer includes at least one of aluminum and copper.

3. The manufacturing method of the display device according to claim 1, wherein The metal layer is formed on the polysilicon layer with a thickness of 100 Å to 700 Å.

4. The manufacturing method of the display device according to claim 1, wherein In the step of crystallizing into the polysilicon layer, the laser beam is irradiated on each region of the substrate with different energy densities to perform crystallization.

5. The manufacturing method of the display device according to claim 4, wherein The energy density of the laser beam is 300 mJ / cm 2 to 500 mJ / cm 2 .

6. The manufacturing method of the display device according to claim 1, wherein The polysilicon layer includes protrusions with a height of 3 nm or less on its surface.

7. The manufacturing method of the display device according to claim 1, wherein After the step of cleaning the amorphous silicon layer with hydrofluoric acid, it further includes a step of cleaning the cleaned amorphous silicon layer with deionized water added with hydrogen.

8. The manufacturing method of the display device according to claim 7, wherein The metal layer includes at least one of aluminum and copper.

9. The manufacturing method of the display device according to claim 1, wherein The step of cleaning the amorphous silicon layer with hydrofluoric acid is a step of spraying the hydrofluoric acid onto the amorphous silicon layer to remove the oxide film formed on the surface of the amorphous silicon layer.

10. The manufacturing method of the display device according to claim 1, wherein The hydrofluoric acid includes 0.5% hydrogen fluoride.

11. The manufacturing method of the display device according to claim 1, wherein Between the step of preparing the substrate and the step of forming the amorphous silicon layer on the substrate, it further includes a step of forming a buffer layer on the substrate.

12. A manufacturing method of a display device, comprising: A step of preparing a substrate defined with a first region and a second region; A step of forming an amorphous silicon layer on the substrate; A step of cleaning the amorphous silicon layer with hydrofluoric acid; A step of irradiating laser beams with different energy densities on the first region and the second region respectively to crystallize the cleaned amorphous silicon layer into a polysilicon layer; A step of directly forming a metal layer on the polysilicon layer, A step of irradiating light on the metal layer, and A step of selecting an optimal energy density of the laser beam by using light reflected from the metal layer.

13. The manufacturing method of the display device according to claim 12, wherein The metal layer includes at least one of aluminum and copper.

14. The manufacturing method of the display device according to claim 12, wherein The metal layer is formed on the polysilicon layer with a thickness of 100 angstroms to 700 angstroms.

15. The manufacturing method of the display device according to claim 12, wherein, The polysilicon layer includes protrusions with a height of 3 nm or less on its surface.

16. The manufacturing method of the display device according to claim 12, wherein, After the step of cleaning the amorphous silicon layer with hydrofluoric acid, it further includes a step of cleaning the cleaned amorphous silicon layer with deionized water added with hydrogen.

17. The manufacturing method of the display device according to claim 16, wherein, The metal layer includes at least one of aluminum and copper.

18. The manufacturing method of the display device according to claim 12, wherein, Between the step of preparing the substrate and the step of forming the amorphous silicon layer on the substrate, it further includes a step of forming a buffer layer on the substrate.

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