Display device and method for manufacturing the same

Abstract

The present invention relates to a display device and a method for manufacturing the same. According to one embodiment, the display device includes a substrate including an opening, a buffer layer located on the substrate, a semiconductor located on the buffer layer, a gate electrode overlapping at least a part of the semiconductor in a plane, a source electrode and a drain electrode electrically connected to the semiconductor, and a light-emitting element electrically connected to the drain electrode. The opening of the substrate overlaps another part of the semiconductor in a plane.

Description

Technical Field

[0001] The present invention relates to a display device and a method for manufacturing the same.

Background Art

[0002] A variety of electronic devices in which a liquid crystal display (LCD) or an organic light emitting diode (OLED) is applied as a display device are used, such as mobile phones, navigation devices, digital cameras, electronic books, portable game machines, or various terminal devices.

[0003] Recently, such display devices tend to be developed to have flexible properties. For example, developments have been made on foldable display devices, bendable display devices, and stretchable display devices.

[0004] Such a flexible display device can include a flexible substrate. Since the flexible substrate is made of a flexible material, the process of forming elements on the flexible substrate may not be easy. Therefore, a process of forming a flexible substrate on a support substrate, forming elements, and then separating the support substrate from the flexible substrate can be performed.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of an embodiment is to provide a display device and a method for manufacturing the same that can improve the characteristics of elements included in a flexible display device.

Means for Solving the Problems

[0006] A display device according to an embodiment includes a substrate including an opening, a buffer layer located on the substrate, a semiconductor located on the buffer layer, a gate electrode overlapping at least a part of the semiconductor in a plane, a source electrode and a drain electrode electrically connected to the semiconductor, and a light-emitting element electrically connected to the drain electrode. The opening of the substrate overlaps another part of the semiconductor in a plane.

[0007] The semiconductor may include a channel region overlapping the gate electrode in a plane, a first region located on one side of the channel region, a second region located on the other side of the channel region, a first contact region located within the first region, and a second contact region located within the second region.

[0008] The opening of the substrate may include a first opening and a second opening. The first opening of the substrate may overlap the first contact region in a plane, and the second opening of the substrate may overlap the second contact region in a plane.

[0009] The source electrode may be in electrical contact with an upper surface of the first contact region, and the drain electrode may be in electrical contact with an upper surface of the second contact region.

[0010] The width of the first opening of the substrate and the width of the first contact region may be the same in a cross section, and the width of the second opening of the substrate and the width of the second contact region may be the same in a cross section.

[0011] The resistance of the first contact region may be lower than the resistance of the first region, and the resistance of the second contact region may be lower than the resistance of the second region.

[0012] The display device according to one embodiment further includes an interlayer insulating film positioned between the semiconductor and the source electrode, and between the semiconductor and the drain electrode. The interlayer insulating film includes a first opening overlapping with the semiconductor and the source electrode in a plane, and a second opening overlapping with the semiconductor and the drain electrode in a plane. The source electrode is electrically connected to the semiconductor through the first opening of the interlayer insulating film, and the drain electrode can be electrically connected to the semiconductor through the second opening of the interlayer insulating film.

[0013] The first opening and the second opening of the interlayer insulating film can overlap with the opening of the substrate in a plane.

[0014] The substrate can include a flexible material.

[0015] The buffer layer can fill the opening of the substrate.

[0016] A method for manufacturing a display device according to one embodiment includes the steps of forming a substrate on a support substrate, patterning the substrate to form an opening in the substrate, forming a buffer layer on the substrate, forming a semiconductor overlapping with the opening of the substrate in a plane on the buffer layer, forming a gate electrode overlapping with the semiconductor in a plane, forming a source electrode and a drain electrode electrically connected to the semiconductor, forming a light-emitting element electrically connected to the drain electrode, and irradiating a laser on the back surface of the support substrate to separate the substrate from the support substrate.

[0017] The semiconductor can include a channel region overlapping with the gate electrode in a plane, a first region positioned on one side of the channel region, a second region positioned on the other side of the channel region, a first contact region positioned within the first region, and a second contact region positioned within the second region.

[0018] The opening of the substrate includes a first opening and a second opening. The first opening of the substrate overlaps with the first contact region on a plane, and the second opening of the substrate overlaps with the second contact region on a plane. The laser beam irradiated at the stage of irradiating the laser can pass through the first opening and the second opening of the substrate and reach the first contact region and the second contact region.

[0019] The source electrode can be in electrical contact with the upper surface of the first contact region, and the drain electrode can be in electrical contact with the upper surface of the second contact region.

[0020] The width of the first opening of the substrate and the width of the first contact region may be the same in cross-section, and the width of the second opening of the substrate and the width of the second contact region may be the same in cross-section.

[0021] The resistance of the first contact region may be lower than the resistance of the first region, and the resistance of the second contact region may be lower than the resistance of the second region.

[0022] A method for manufacturing a display device according to an embodiment further includes, after the step of forming the gate electrode, a step of forming an interlayer insulating film on the gate electrode, and a step of forming a first opening and a second opening in the interlayer insulating film. The source electrode and the drain electrode are located on the interlayer insulating film. The first opening of the interlayer insulating film overlaps with the semiconductor and the source electrode on a plane, and the second opening of the interlayer insulating film overlaps with the semiconductor and the drain electrode on a plane. The source electrode is electrically connected to the semiconductor through the first opening of the interlayer insulating film, and the drain electrode can be electrically connected to the semiconductor through the second opening of the interlayer insulating film.

[0023] The first opening and the second opening of the interlayer insulating film can overlap with the opening of the substrate.

[0024] The support substrate includes a rigid material, and the substrate can include a flexible material.

[0025] In the step of forming the buffer layer, the buffer layer can fill the opening of the substrate.

Advantages of the Invention

[0026] According to an embodiment, the characteristics of elements included in the flexible display device can be improved.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0028] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. The present invention can be realized in various different forms and is not limited to the embodiments described here.

[0029] In order to clearly explain the present invention, parts that are unnecessary for the explanation are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0030] Also, the sizes and thicknesses of the respective configurations shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, the thicknesses are enlarged to clearly represent a plurality of layers and regions. And in the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

[0031] When an element such as a layer is referred to as being "above", "connected" or "coupled" to another element or layer, this can mean directly connected or coupled to the other element or layer. There may be intervening elements or layers or intermediate elements or layers. However, when an element or layer is referred to as being "directly connected" or "directly coupled" to another element or layer, there are no intervening elements or layers. For this reason, the term "coupled" can mean a physical, electrical and / or fluid connection with or without intervening elements. Also, when an element is referred to as being in "contact" with another element, the element can be in a state of "electrical contact" or "physical contact" with the other element; or in a state of "indirect contact" or "direct contact" with the other element.

[0032] In the specification and claims, the expression "at least one of" shall be taken to include the meaning of "at least one selected from" in its meaning and interpretation. For example, "at least one of A and B" can be understood to mean "A, B or A and B". In the specification and claims, the term "and / or" is intended to include any combination of the terms "and" and "or" for its meaning and interpretation. For example, "A and / or B" can be understood to mean "A, B or A and B". The terms "and" and "or" can be used in a conjunctive or disjunctive sense and can be understood as equivalent to "and / or".

[0033] Also, throughout the specification, when a portion includes a certain component, this means that other components are not excluded and further components can be included, unless otherwise stated to the contrary.

[0034] Also, throughout the specification, when "in a plane" is mentioned, this means when the target portion is viewed from above, and when "in a cross-section" is mentioned, this means when the cross-section obtained by vertically cutting the target portion is viewed from the side.

[0035] Unless otherwise defined or implied in this specification, all terms used, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms such as those defined in commonly used dictionaries shall be interpreted to have a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless clearly defined in the specification.

[0036] Hereinafter, a display device according to an embodiment will be described with reference to FIG. 1.

[0037] FIG. 1 is a schematic cross-sectional view showing a display device according to an embodiment.

[0038] As shown in FIG. 1, it includes a substrate 110, a transistor TFT located on the substrate 110, and a light-emitting element ED connected to the transistor TFT.

[0039] The substrate 110 can be a flexible substrate that can be bent, folded, rolled, etc. For example, the substrate 110 can include substances such as polystyrene, polyvinyl alcohol, Polymethylmethacrylate, polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, triacetate cellulose, cellulose acetate propionate, etc. The substrate 110 can be single-layer or multi-layer. The substrate 110 can have at least one base layer including sequentially laminated polymer resins and at least one inorganic layer laminated alternately.

[0040] The substrate 110 can include an opening 115. The opening 115 is formed to penetrate the substrate 110. The opening 115 can overlap with the transistor TFT in a plane. The opening 115 can overlap with a partial region of the semiconductor 130 of the transistor TFT, which will be described later again.

[0041] On the substrate 110, a buffer layer 111 for flattening the surface of the substrate 110 and blocking the penetration of impurity elements can be further located. The buffer layer 111 can be located within the opening 115 of the substrate 110. The buffer layer 111 is formed to fill the opening 115 of the substrate 110, and the upper surface of the buffer layer 111 can be formed flat.

[0042] The buffer layer 111 can include an inorganic insulating material or an organic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy). The buffer layer 111 can be a single layer or a multilayer structure of the above materials. A barrier layer (not shown) can be further located on the substrate 110. At this time, the barrier layer can be located between the substrate 110 and the buffer layer 111. The barrier layer can include an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy). The barrier layer can be a single layer or a multilayer structure of the above materials.

[0043] A semiconductor 130 can be located on the buffer layer 111. The semiconductor 130 can include any one of amorphous silicon, polycrystalline silicon, and an oxide semiconductor. As an example, the semiconductor 130 can include low-temperature polysilicon (LTPS), or can include an oxide semiconductor material including at least one of zinc (Zn), indium (In), gallium (Ga), tin (Sn), and mixtures thereof. As an example, the semiconductor 130 can include IGZO (Indium-Gallium-Zinc Oxide). The semiconductor 130 can include a first region 131, a channel region 132, and a second region 133 classified according to the presence or absence of impurity doping. The first region 131 and the second region 133 can be located on both sides of the channel region 132 of the semiconductor 130, respectively. The first region 131 and the second region 133 can have conductive characteristics corresponding to a conductor.

[0044] The semiconductor 130 can further include a first contact region 135 located within the first region 131 and a second contact region 137 located within the second region 133. The first region 131 can be located on both sides of the first contact region 135. For example, the first contact region 135 may be surrounded by the first region 131. However, this is only one example, and the position of the first contact region 135 can also be changed. For example, the first contact region 135 can also be located between the channel region 132 and the first region 131. The second region 133 can be located on both sides of the second contact region 137. For example, the second contact region 137 may be surrounded by the second region 133. However, this is only one example, and the position of the second contact region 137 can also be changed. For example, the second contact region 137 can also be located between the channel region 132 and the second region 133.

[0045] The first contact region 135 and the second contact region 137 can overlap the opening 115 of the substrate 110 in a plane. The opening 115 of the substrate 110 can be located below the first contact region 135 and can be located below the second contact region 137.

[0046] The first contact region 135 can overlap the opening 115 in a direction perpendicular to the upper surface of the substrate 110. The thickness of the first contact region 135 may be similar to the thickness of the first region 131. For example, the thickness of the first contact region 135 may be substantially the same as the thickness of the first region 131. However, it is not limited thereto, and the thickness of the first contact region 135 may be smaller than the thickness of the first region 131. The width of the first contact region 135 can correspond to the width of the portion of the opening 115 that overlaps the first contact region 135. For example, the width of the first contact region 135 may be substantially the same as the width of the portion of the opening 115 that overlaps the first contact region 135. However, it is not limited thereto, and the width of the first contact region 135 may be smaller or larger than the width of the portion of the opening 115 that overlaps the first contact region 135.

[0047] The second contact region 137 can overlap with the opening 115 in a direction perpendicular to the upper surface of the substrate 110. The thickness of the second contact region 137 may be similar to the thickness of the second region 133. For example, the thickness of the second contact region 137 may be substantially the same as the thickness of the second region 133. However, it is not limited thereto, and the thickness of the second contact region 137 may be smaller than the thickness of the second region 133. The width of the second contact region 137 can correspond to the width of the portion of the opening 115 that overlaps with the second contact region 137. For example, the width of the second contact region 137 may be substantially the same as the width of the portion of the opening 115 that overlaps with the second contact region 137. However, it is not limited thereto, and the width of the second contact region 137 may be smaller or larger than the width of the portion of the opening 115 that overlaps with the second contact region 137.

[0048] The first contact region 135 and the second contact region 137 can have conductive characteristics corresponding to a conductor, similar to the first region 131 and the second region 133. The conductive characteristics of the first contact region 135 and the second contact region 137 may be different from the conductive characteristics of the first region 131 and the second region 133. For example, the resistance of the first contact region 135 and the second contact region 137 may be lower than the resistance of the first region 131 and the second region 133.

[0049] A gate insulating film 120 can be located on the semiconductor 130. The gate insulating film 120 can cover the semiconductor 130 and the buffer layer 111. The gate insulating film 120 can include an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy), etc. The gate insulating film 120 can be a single layer or a multilayer structure of the above substances.

[0050] A gate electrode 124 can be located on the gate insulating film 120. The gate electrode 124 can overlap at least a part of the semiconductor 130. The gate electrode 124 can include metals or metal alloys such as copper (Cu), molybdenum (Mo), aluminum (Al), silver (Ag), chromium (Cr), tantalum (Ta), titanium (Ti). The gate electrode 124 can be composed of a single layer or a multilayer. For example, the gate electrode 124 can be composed of a bilayer and can include a layer containing aluminum (Al) and a layer containing titanium (Ti).

[0051] After forming the gate electrode 124, a doping process or plasma treatment can be performed. The portion of the semiconductor 130 that overlaps the gate electrode 124 on the plane is not subjected to doping or plasma treatment, and the portion of the semiconductor 130 that is not covered by the gate electrode 124 can be doped or plasma-treated to have the same characteristics as a conductor. The region of the semiconductor 130 that overlaps the gate electrode 124 on the plane can become the channel region 132. The first region 131, the second region 133, the first contact region 135, and the second contact region 137 of the semiconductor 130 do not have to overlap the gate electrode 124. The gate electrode 124 does not have to overlap the opening 115 of the substrate 110. The channel region 132 of the semiconductor 130 does not have to overlap the opening 115 of the substrate 110.

[0052] An interlayer insulating film 160 can be located on the gate electrode 124. The interlayer insulating film 160 can cover the gate electrode 124 and the gate insulating film 120. The interlayer insulating film 160 can include inorganic insulating substances such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy). The interlayer insulating film 160 can be a single layer or a multilayer structure of the above substances.

[0053] On the interlayer insulating film 160, the source electrode 173 and the drain electrode 175 can be located. Openings 161 overlapping the source electrode 173 and the semiconductor 130 are formed in the interlayer insulating film 160 and the gate insulating film 120. The opening 161 can overlap the first contact region 135 of the semiconductor 130. The source electrode 173 can be connected to the first contact region 135 of the semiconductor 130 through the opening 161. The source electrode 173 can contact the upper surface of the first contact region 135. Openings 163 overlapping the drain electrode 175 and the semiconductor 130 are formed in the interlayer insulating film 160 and the gate insulating film 120. The opening 163 can overlap the second contact region 137 of the semiconductor 130. The drain electrode 175 can be connected to the second contact region 137 of the semiconductor 130 through the opening 163. The drain electrode 175 can contact the upper surface of the second contact region 137.

[0054] The openings 161 and 163 in the interlayer insulating film 160 can overlap the opening 115 in the substrate 110. Accordingly, the portion where the source electrode 173 and the semiconductor 130 contact each other can overlap the opening 115 in the substrate 110. Also, the portion where the drain electrode 175 and the semiconductor 130 contact each other can overlap the opening 115 in the substrate 110.

[0055] The semiconductor 130, the gate electrode 124, the source electrode 173, and the drain electrode 175 described above constitute one transistor TFT. Depending on the embodiment, the transistor TFT can also include only the first region 131 and the second region 133 of the semiconductor 130 instead of the source electrode 173 and the drain electrode 175. Although one transistor TFT is shown in FIG. 1, a display device according to an embodiment can include a plurality of pixels, and each of the plurality of pixels can include a multiple transistor TFT.

[0056] The source electrode 173 and the drain electrode 175 can include metals and metal alloys such as aluminum (Al), copper (Cu), silver (Ag), gold (Au), platinum (Pt), palladium (Pd), nickel (Ni), molybdenum (Mo), tungsten (W), titanium (Ti), chromium (Cr), tantalum (Ta), etc. The source electrode 173 and the drain electrode 175 can be composed of a single layer or multiple layers. For example, the source electrode 173 and the drain electrode 175 can have a triple-layer structure including a lower layer containing refractory metals such as molybdenum, chromium, tantalum, and titanium or alloys thereof, an intermediate layer containing aluminum-based metals, silver-based metals, and copper-based metals with low resistivity, and an upper layer containing refractory metals such as molybdenum, chromium, tantalum, and titanium.

[0057] A protective film 180 can be located on the source electrode 173 and the drain electrode 175. The protective film 180 can cover the source electrode 173, the drain electrode 175, and the interlayer insulating film 160. The protective film 180 is for flattening the surface of the substrate 110 provided with the transistor TFT and can be an organic insulating film. The protective film 180 can include organic insulating substances such as general-purpose polymers like polymethylmethacrylate (PMMA) and polystyrene (PS), polymer derivatives having a phenolic group, acrylic polymers, imide polymers, polyimides, and siloxane-based polymers.

[0058] A light-emitting element ED can be located on the protective film 180. The light-emitting element ED can be connected to the transistor TFT. The light-emitting element ED can include a first electrode 191, a light-emitting layer 370, and a second electrode 270.

[0059] The first electrode 191 can be located on the protective film 180. The first electrode 191 is also called an anode electrode and can be composed of a single layer containing a transparent conductive oxide or a metal substance or a multilayer containing these. The transparent conductive oxide can include ITO (Indium Tin Oxide), poly(poly)-ITO, IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), and / or ITZO (Indium Tin Zinc Oxide), etc. The metal substance can include silver (Ag), molybdenum (Mo), copper (Cu), gold (Au), and aluminum (Al), etc. For example, the first electrode 191 can include a lower layer, an intermediate layer, and an upper layer. The lower layer of the first electrode 191 can be located directly above the protective film 180, the intermediate layer can be located above the lower layer, and the upper layer can be located above the intermediate layer. At this time, the intermediate layer of the first electrode 191 can be made of a different material from the lower layer and the upper layer. For example, the intermediate layer can be made of silver (Ag), and the lower layer and the upper layer can be made of ITO.

[0060] The protective film 180 can include an opening 181 that overlaps the first electrode 191 and the drain electrode 175 in a plane. The first electrode 191 can be connected to the drain electrode 175 through the opening 181. Therefore, the first electrode 191 can be connected to the transistor TFT.

[0061] The bank 350 can be located on the first electrode 191. The bank 350, also called a Pixel Defining Layer (PDL), includes a pixel opening 351 that overlaps at least a part of the first electrode 191. At this time, the pixel opening 351 can overlap the central part of the first electrode 191 and may not overlap the edge of the first electrode 191. Therefore, the area of the pixel opening 351 on the plane may be smaller than the area of the first electrode 191. The bank 350 can be an organic insulating film containing one or more substances selected from the group consisting of polyimide, polyamide, acrylic resin, benzocyclobutene, and phenolic resin. Or, the bank 350 can also contain inorganic insulating substances such as silicon nitride (SiNx), silicon oxide (SiOx), and silicon oxynitride (SiOxNy). Or, the bank 350 can be composed of a Black Pixel Define Layer (BPDL) containing a light-blocking substance. At this time, the light-blocking substance can include carbon black, carbon nanotubes, a resin or paste containing a black dye, metal particles such as nickel, aluminum, molybdenum, and their alloys, metal oxide particles (e.g., chromium oxide), or metal nitride particles (e.g., chromium nitride). When the bank 350 contains a light-blocking substance, external light reflection by the metal structure disposed below the bank 350 can be reduced. However, the present invention is not limited thereto, and the bank 350 can contain a light-transmissive organic insulating substance without containing a light-blocking substance.

[0062] The light-emitting layer 370 can be positioned within the pixel opening 351 of the bank 350. The light-emitting layer 370 can overlap with the first electrode 191. The light-emitting layer 370 can include an organic substance that emits light such as red, green, or blue light. The light-emitting layer 370 can include a low-molecular or high-molecular organic substance. Although the light-emitting layer 370 is illustrated as a single layer, it is not limited thereto, and actually, auxiliary layers such as a hole injection layer (HIL), a hole transporting layer (HTL), an electron transporting layer (ETL), and an electron injection layer (EIL) can be further positioned above and below the light-emitting layer 370. At this time, a hole injection layer and a hole transport layer can be positioned below the light-emitting layer 370, and an electron transport layer and an electron injection layer can be positioned above the light-emitting layer 370.

[0063] The second electrode 270 can be positioned on the light-emitting layer 370 and the bank 350. The second electrode 270 can be entirely positioned in most regions on the substrate 110. The second electrode 270 is also called a cathode electrode and can include a reflective metal such as calcium (Ca), barium (Ba), magnesium (Mg), aluminum (Al), silver (Ag), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), etc., or a transparent conductive oxide (TCO) such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0064] The first electrode 191, the light-emitting layer 370, and the second electrode 270 can together form a light-emitting element ED. At this time, the first electrode 191 can be an anode electrode that is a hole injection electrode, and the second electrode 270 can be a cathode electrode that is an electron injection electrode. However, it is not limited thereto, and depending on the driving method of the display device, the anode electrode and the cathode electrode can be formed in the reverse manner.

[0065] Holes and electrons are respectively injected into the light-emitting layer 370 from the first electrode 191 and the second electrode 270, and light is emitted when the injected holes and electrons combine and the exciton falls from the excited state to the ground state.

[0066] Although not shown in the figure, a sealing layer can be further located on the second electrode 270. The sealing layer is for protecting the light-emitting element ED from moisture, oxygen, etc. that can flow in from the outside, and can include at least one inorganic film and at least one organic film. For example, the sealing layer can have a structure in which a first inorganic sealing layer, an organic sealing layer, and a second inorganic sealing layer are laminated. However, this is only one example, and the number of inorganic films and organic films constituting the sealing layer can be variously changed.

[0067] A display device according to an embodiment can include a plurality of pixels, and each pixel can include a plurality of transistors and a light-emitting element connected thereto. Although the structure of one transistor connected to the light-emitting element has been described above, a plurality of transistors can be located within one pixel. For example, one pixel can include two transistors and a light-emitting element connected thereto. Some of the plurality of transistors included in one pixel can be composed of polycrystalline transistors, and some of the others can be composed of oxide transistors.

[0068] Next, a method for manufacturing a display device according to an embodiment will be described with reference to FIGS. 2 to 12.

[0069] FIGS. 2 to 12 are schematic cross-sectional views showing a method for manufacturing a display device according to an embodiment.

[0070] First, as shown in FIG. 2, a substrate 110 is formed on a support substrate 100.

[0071] The support substrate 100 can be made of a rigid material. For example, the support substrate 100 can be made of glass, a metallic material, etc. The substrate 110 formed on the support substrate 100 can be made of a flexible material. For example, the substrate 110 can be made of a plastic material such as polyimide. The support substrate 100 can play a role of supporting the substrate 110 while a process of forming a predetermined element is performed on the substrate 110.

[0072] The substrate 110 can be composed of a single layer or multiple layers. A predetermined other layer can also be located between the support substrate 100 and the substrate 110. For example, a layer for facilitating separation of the substrate 110 from the support substrate 100 in subsequent processes can be located between the support substrate 100 and the substrate 110.

[0073] Referring to FIG. 3, the substrate 110 is patterned to form an opening 115 in the substrate 110. The opening 115 can be formed through a process of removing a partial region of the substrate 110. The opening 115 can penetrate the substrate 110. The depth of the opening 115 can correspond to the thickness of the substrate 110. Accordingly, at least a part of the upper surface of the support substrate 100 may be exposed by the opening 115. A plurality of openings 115 can be formed in the substrate 110.

[0074] Referring to FIG. 4, a buffer layer 111 is formed on the substrate 110 and the support substrate 100 using an inorganic insulating material or an organic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy). The buffer layer 111 can be formed entirely on the substrate 110. The buffer layer 111 can also be formed within the opening 115 of the substrate 110. The buffer layer 111 is formed to fill the opening 115 of the substrate 110, and the upper surface of the buffer layer 111 can be formed flat.

[0075] Referring to FIG. 5, a semiconductor 130 is formed on the buffer layer 111 using a semiconductor material such as amorphous silicon, polycrystalline silicon, and an oxide semiconductor material. The semiconductor 130 can overlap the opening 115 of the substrate 110. At this time, the semiconductor 130 can overlap a plurality of openings 115. For example, the semiconductor 130 can overlap two openings 115 spaced apart from each other at a predetermined interval.

[0076] Referring to FIG. 6, a gate insulating film 120 is formed on the semiconductor 130 and the buffer layer 111 using an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiOxNy).

[0077] Next, a gate electrode 124 is formed on the gate insulating film 120 using a metal or metal alloy such as copper (Cu), molybdenum (Mo), aluminum (Al), silver (Ag), chromium (Cr), tantalum (Ta), titanium (Ti). At this time, after forming two or more metal material layers by continuous evaporation and then patterning them simultaneously, the gate electrode 124 can also be formed. The gate electrode 124 can overlap the semiconductor 130. At this time, the gate electrode 124 can overlap a partial region of the semiconductor 130 and may not overlap another partial region.

[0078] Referring to FIG. 7, a doping process or plasma treatment can be performed. Using the gate electrode 124 as a mask, a substance such as boron (B) can be implanted over the entire surface of the gate insulating film 120. The portion of the semiconductor 130 covered by the gate electrode 124 is not doped or plasma-treated and can become the channel region 132. The portion of the semiconductor 130 not covered by the gate electrode 124 can be doped or plasma-treated to have the same characteristics as a conductor and can become the first region 131 and the second region 133. The first region 131 and the second region 133 of the semiconductor 130 can be located on both sides of the channel region 132. That is, the channel region 132 of the semiconductor 130 can be located between the first region 131 and the second region 133. The first region 131 and the second region 133 of the semiconductor 130 can overlap the opening 115 of the substrate 110. The opening 115 of the substrate 110 may not overlap the channel region 132 of the semiconductor 130. The opening 115 of the substrate 110 may not overlap the gate electrode 124.

[0079] Referring to FIG. 8, an interlayer insulating film 160 is formed using an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiOxNy) on the gate electrode 124. The interlayer insulating film 160 and the gate insulating film 120 are patterned using a photolithography process to form openings 161 and 163. The upper surface of the first region 131 of the semiconductor 130 may be exposed by the opening 161. The upper surface of the second region 133 of the semiconductor 130 may be exposed by the opening 163.

[0080] Next, source electrode 173 and drain electrode 175 are formed on the interlayer insulating film 160 by using metals or metal alloys such as aluminum (Al), copper (Cu), silver (Ag), gold (Au), platinum (Pt), palladium (Pd), nickel (Ni), molybdenum (Mo), tungsten (W), titanium (Ti), chromium (Cr), tantalum (Ta). At this time, after forming two or more metal material layers by continuous vapor deposition, these can also be simultaneously patterned to form source electrode 173 and drain electrode 175. For example, after sequentially forming a material layer containing titanium, a material layer containing aluminum, and a material layer containing titanium, these material layers can be patterned to form source electrode 173 and drain electrode 175. Source electrode 173 can be connected to the first region 131 of semiconductor 130 through opening 161, and drain electrode 175 can be connected to the second region 133 of semiconductor 130 through opening 163.

[0081] Openings 161 and 163 of interlayer insulating film 160 can overlap with opening 115 of substrate 110 on the plane. Therefore, the portion where source electrode 173 and semiconductor 130 are in contact with each other can overlap with opening 115 of substrate 110. Also, the portion where drain electrode 175 and semiconductor 130 are in contact with each other can overlap with opening 115 of substrate 110.

[0082] Referring to FIG. 9, a protective film 180 can be formed on source electrode 173 and drain electrode 175 by using organic insulating materials such as general-purpose polymers like polymethylmethacrylate (PMMA) and polystyrene (PS), polymer derivatives having a phenolic group, acrylic polymers, imide polymers, polyimide, and siloxane polymers. Protective film 180 is patterned to form opening 181. The upper surface of drain electrode 175 may be exposed to the outside through opening 181.

[0083] Next, the first electrode 191 can be formed on the protective film 180 by using a transparent conductive oxide or a metallic substance. At this time, after forming two or more substance layers by continuous deposition, these can also be simultaneously patterned to form the first electrode 191. For example, after sequentially forming a substance layer containing ITO, a substance layer containing silver (Ag), and a substance layer containing ITO, these substance layers can be patterned to form the first electrode 191. The first electrode 191 can be connected to the drain electrode 175 through the opening 181.

[0084] Referring to FIG. 10, the bank 350 can be formed on the first electrode 191 and the protective film 180 by using an organic insulating substance or an inorganic insulating substance. The bank 350 can be patterned to form the pixel opening 351. The pixel opening 351 can overlap the first electrode 191 on a plane. At this time, the pixel opening 351 can overlap the central portion of the first electrode 191 and may not overlap the edge portion of the first electrode 191.

[0085] Next, the light-emitting layer 370 can be formed in the pixel opening 351. In FIG. 10, the light-emitting layer 370 is illustrated as a single layer, but is not limited thereto. Actually, auxiliary layers such as a hole injection layer (HIL), a hole transporting layer (HTL), an electron transporting layer (ETL), and an electron injection layer (EIL) can be further formed above and below the light-emitting layer 370.

[0086] Next, a second electrode 270 can be formed on the light-emitting layer 370 and the bank 350 by using a reflective metal containing calcium (Ca), barium (Ba), magnesium (Mg), aluminum (Al), silver (Ag), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), etc., or a transparent conductive oxide (TCO) such as indium tin oxide (ITO) or indium zinc oxide (IZO). The second electrode 270 can be entirely located in most regions on the substrate 110. The first electrode 191, the light-emitting layer 370, and the second electrode 270 can together form a light-emitting element ED.

[0087] Although illustration is omitted, a sealing layer can be formed on the second electrode 270.

[0088] Referring to FIG. 11, a laser beam can be irradiated on the back surface of the support substrate 100. By irradiating the support substrate 100 with a laser beam, the support substrate 100 can be separated from the substrate 110. At this time, the laser beam can be entirely irradiated on the back surface of the support substrate 100. The energy density of the laser equipment used in the laser irradiation process is about 300 mJ / cm 2 or more and can be about 400 mJ / cm 2 or less. When the energy density is less than about 300 mJ / cm 2 , the separation of the support substrate 100 from the substrate 110 may not be performed well. When the energy density exceeds about 400 mJ / cm 2 , the substrate 110 may be damaged. However, it is not limited thereto, and the energy density of the laser can be appropriately selected in consideration of the material characteristics of the substrate 110 or the support substrate 100, the adhesive force between them, etc. The scan pitch of the laser equipment used in the laser irradiation process is about 15 μm or more and can be about 30 μm or less.

[0089] The laser beam irradiated in the laser irradiation process can pass through the support substrate 100 and reach the substrate 110, but it may not pass through the substrate 110. In a display device according to an embodiment, since the opening 115 can be formed in the substrate 110, the laser beam can pass through the opening 115 of the substrate 110. Therefore, the laser beam can pass through the buffer layer 111 through the opening 115 of the substrate 110 and reach the semiconductor 130. When the semiconductor 130 is irradiated with the laser beam, it may affect the characteristics of the semiconductor 130. For example, the resistance of the portion of the semiconductor 130 irradiated with the laser beam may become low.

[0090] Referring to FIG. 12, the support substrate 100 can be removed by the laser irradiation process, and the portions of the semiconductor 130 irradiated with the laser beam can become the first contact region 135 and the second contact region 137. The portion of the first region 131 of the semiconductor 130 irradiated with the laser beam can become the first contact region 135. The portion of the second region 133 of the semiconductor 130 irradiated with the laser beam can become the second contact region 137.

[0091] The first region 131 can be located on both sides of the first contact region 135. For example, the first contact region 135 may be surrounded by the first region 131. However, it is not limited thereto, and the position of the first contact region 135 can also be changed. For example, the first contact region 135 can also be located between the channel region 132 and the first region 131. The second region 133 can be located on both sides of the second contact region 137. For example, the second contact region 137 may be surrounded by the second region 133. However, it is not limited thereto, and the position of the second contact region 137 can also be changed. For example, the second contact region 137 can also be located between the channel region 132 and the second region 133.

[0092] The first contact region 135 can overlap with the opening 115 in a direction perpendicular to the upper surface of the substrate 110. The thickness of the first contact region 135 may be similar to the thickness of the first region 131. For example, the thickness of the first contact region 135 may be substantially the same as the thickness of the first region 131. However, it is not limited thereto, and the thickness of the first contact region 135 may be smaller than the thickness of the first region 131. The width of the first contact region 135 can correspond to the width of the portion of the opening 115 that overlaps with the first contact region 135. For example, the width of the first contact region 135 may be substantially the same as the width of the portion of the opening 115 that overlaps with the first contact region 135. However, it is not limited thereto, and the width of the first contact region 135 may be smaller or larger than the width of the portion of the opening 115 that overlaps with the first contact region 135. The thickness, width, etc. of the first contact region 135 can be changed by the energy density of the laser beam, the irradiation time, etc.

[0093] The second contact region 137 can overlap with the opening 115 in a direction perpendicular to the upper surface of the substrate 110. The thickness of the second contact region 137 may be similar to the thickness of the second region 133. For example, the thickness of the second contact region 137 may be substantially the same as the thickness of the second region 133. However, it is not limited thereto, and the thickness of the second contact region 137 may be smaller than the thickness of the second region 133. The width of the second contact region 137 can correspond to the width of the portion of the opening 115 that overlaps with the second contact region 137. For example, the width of the second contact region 137 may be substantially the same as the width of the portion of the opening 115 that overlaps with the second contact region 137. However, it is not limited thereto, and the width of the second contact region 137 may be smaller or larger than the width of the portion of the opening 115 that overlaps with the second contact region 137. The thickness, width, etc. of the second contact region 137 can be changed by the energy density of the laser beam, the irradiation time, etc.

[0094] The first contact region 135 and the second contact region 137 can have conductive characteristics corresponding to a conductor, similar to the first region 131 and the second region 133. The conductive characteristics of the first contact region 135 and the second contact region 137 may be different from those of the first region 131 and the second region 133. For example, the resistance of the first contact region 135 and the second contact region 137 may be lower than the resistance of the first region 131 and the second region 133. The first contact region 135 can be in contact with the source electrode 173, and the second contact region 137 can be in contact with the drain electrode 175. By thus reducing the resistance of the portion of the semiconductor 130 that contacts the source electrode 173 and the drain electrode 175, the characteristics of the transistor TFT can be improved.

[0095] In a display device according to an embodiment, the support substrate 100 can be separated from the substrate 110 through a laser irradiation process, and at the same time, the contact characteristics between the semiconductor and the source / drain electrodes can be improved. By forming an opening in a predetermined region of the substrate, the characteristics of the elements included in the display device can be improved in the process of separating the support substrate 100 from the substrate 110.

[0096] Hereinafter, with reference to FIGS. 13 and 14, the laser process used in a method for manufacturing a display device according to an embodiment will be further described.

[0097] FIG. 13 is a plan view showing the positional relationship between the display device and the laser equipment in the laser process used in a method for manufacturing a display device according to an embodiment, and FIG. 14 is a schematic cross-sectional view taken along line XIV-XIV of FIG. 13.

[0098] Referring to FIGS. 13 and 14, the laser equipment 2000 is positioned so as to overlap one side edge of the display device 1000. At this time, the laser equipment 2000 can be positioned on the rear surface of the display device. Therefore, the laser beam irradiated from the laser equipment 2000 can reach the rear surface of the display device 1000. The support substrate can be positioned on the rear surface of the display device 1000, and the laser beam can reach the support substrate.

[0099] The energy density of the laser equipment 2000 used in the laser irradiation process is about 300 mJ / cm 2 or more, and can be about 400 mJ / cm 2 or less. The width (Wa) of the laser equipment 2000 can be about 480 μm, and the width (Wb) of the laser beam irradiated from the laser equipment 2000 and reaching the display device 1000 can be about 680 μm. The laser equipment 2000 can irradiate a laser beam onto the support substrate 100 located about 100 μm from the display device 1000. At this time, the energy of the laser beam irradiated on the part of the display device 1000 overlapping with the laser equipment 2000 may be stronger than the energy of the laser beam reaching its periphery.

[0100] The laser equipment 2000 can irradiate a laser beam while moving from one side edge to the other side edge of the display device 1000. After the laser equipment 2000 irradiates a laser beam at a predetermined (or selectable) point for a predetermined (or selectable) time, it moves by a predetermined (or selectable) distance and irradiates the laser beam again. At this time, the distance that the laser equipment 2000 moves at one time is also called the scan pitch, which is about 15 μm or more and can be about 30 μm or less. Since the scan pitch is sufficiently smaller than the width of the laser equipment 2000, the display device 1000 can be irradiated with the laser beam uniformly as a whole.

[0101] Hereinafter, a display device according to an embodiment and a display device according to a reference example will be compared with reference to FIGS. 15 to 20.

[0102] FIG. 15 is a schematic cross-sectional view showing a display device according to a reference example. FIG. 16 is a graph showing the threshold voltages of transistors in a display device according to an embodiment and a display device according to a reference example. FIG. 17 is a graph showing the S-factors of transistors in a display device according to an embodiment and a display device according to a reference example. FIG. 18 is a graph showing the mobilities of transistors in a display device according to an embodiment and a display device according to a reference example. FIG. 19 is a graph showing the contact resistances of transistors in a display device according to an embodiment and a display device according to a reference example. FIG. 20 is a graph showing the sheet resistances of transistors in a display device according to an embodiment and a display device according to a reference example.

[0103] Referring to FIG. 15, the display device according to the reference example includes a substrate 110, a transistor TFT located on the substrate 110, and a light-emitting element ED connected to the transistor TFT.

[0104] In the display device according to the embodiment of FIG. 1, an opening may be formed in the substrate, but in the display device according to the reference example, no opening is formed in the substrate 110. For manufacturing the display device according to the reference example, the substrate 110 can be formed on a support substrate, and after forming the transistor TFT and the light-emitting element ED on the substrate 110, the support substrate can be removed from the substrate 110. A step of irradiating a laser beam on the back surface of the display device can be performed for removing the support substrate. Since no opening is formed in the substrate 110, the laser cannot pass through the substrate 110 at all. For example, the laser beam irradiated in the laser irradiation step cannot reach the semiconductor 130.

[0105] In the display device according to the reference example, a heat treatment step of applying heat in the chamber can be performed to improve the contact characteristics between the semiconductor 130 and the source and drain electrodes 173, 175. The heat treatment step can be performed at a temperature of about 360 degrees to about 370 degrees for about 15 minutes to about 30 minutes. At this time, the heat supplied into the chamber is not selectively applied to the contact portion between the semiconductor 130 and the source and drain electrodes 173, 175, but is transmitted to the entire display device.

[0106] Referring to FIG. 16, the threshold voltage of the transistor in the display device (Ref) according to the reference example can be about -2.55V. The threshold voltage of the transistor in the display device (Emb) according to the embodiment of FIG. 1 can be about -3.66V. When the threshold voltage of the transistor is about -3.9V or more and about -2.55V or less, the display device can operate normally. Therefore, the display device (Ref) according to the reference example and the display device (Emb) according to the embodiment of FIG. 1 can each belong to the normal operation range.

[0107] Referring to FIG. 17, the S-factor in the display device (Ref) according to the reference example can be about 0.54V / dec. The S-factor in the display device (Emb) according to the embodiment of FIG. 1 can be about 0.46V / dec. The S-factor indicates the current-voltage characteristics of the transistor and means the magnitude of the gate voltage required to increase the drain current by 10 times when a gate voltage below the threshold voltage is applied. It can be considered that the smaller the S-factor, the faster the conversion speed between the turn-on state and the turn-off state of the transistor. For example, the smaller the S-factor, the faster the driving speed of the transistor may be. The S-factor in the display device (Emb) according to the embodiment of FIG. 1 is lower than that of the display device (Ref) according to the reference example, and it can be considered that the driving speed of the transistor is faster.

[0108] Referring to FIG. 18, the mobility in the display device (Ref) according to the reference example can be about 88.88 cm 2 / Vs. The mobility in the display device (Emb) according to the embodiment of FIG. 1 can be about 101.39 cm 2 / Vs. It can be confirmed that the carrier movement speed of the transistor in the display device (Emb) according to the embodiment of FIG. 1 is higher than that of the display device (Ref) according to the reference example.

[0109] Referring to FIG. 19, the contact resistance (Rc) in the display device (Ref) according to the reference example can be about 2000 Ω or more. The contact resistance in the display device (Emb) according to the embodiment of FIG. 1 can be about 400 Ω or less. It can be confirmed that the contact resistance between the semiconductor of the transistor and the source / drain electrode in the display device (Emb) according to the embodiment of FIG. 1 is significantly lower than that in the display device (Ref) according to the reference example.

[0110] Referring to FIG. 20, the sheet resistance (Rs) in the display device (Ref) according to the reference example can be about 3000 Ω / □ (ohm / square) or more. The sheet resistance in the display device (Emb) according to the embodiment of FIG. 1 can be about 800 Ω / □ (ohm / square) or less. It can be confirmed that the sheet resistance of the transistor in the display device (Emb) according to the embodiment of FIG. 1 is significantly lower than that in the display device (Ref) according to the reference example.

[0111] In order to improve the contact characteristics between the semiconductor and the source / drain electrode, overall heat treatment can be performed in the display device according to the reference example, and partial laser irradiation can be performed in the display device according to the embodiment of FIG. 1. As a result, as described in FIGS. 16 to 20, the characteristics of the transistor in the display device according to the embodiment of FIG. 1 can be further improved. For example, it can be confirmed that the transistor in the display device according to the embodiment of FIG. 1 can have a faster driving speed, higher mobility, and lower resistance.

[0112] Moreover, since the characteristics of the transistor can be simultaneously improved by using the laser irradiation process for separating the support substrate, the process can be simplified and the process time can be shortened.

[0113] The above description is an exemplification of the technical features of the present invention, and various modifications and variations will be possible for those having ordinary knowledge in the technical field to which the present invention pertains. Therefore, the above-described embodiments of the present invention can be implemented individually or in combination with each other.

[0114] Therefore, the embodiments disclosed in this specification are not for limiting the technical idea of the present invention, but for explaining the disclosed technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments.

Claims

1. A substrate including an opening, A buffer layer located on the substrate, A semiconductor located on the buffer layer, A gate electrode overlapping at least a part of the semiconductor in a plane, A source electrode and a drain electrode electrically connected to the semiconductor, and A light-emitting element electrically connected to the drain electrode, and A display device in which the opening of the substrate overlaps another part of the semiconductor in a plane.

2. The semiconductor includes A channel region overlapping the gate electrode in a plane, A first region located on one side of the channel region, A second region located on the other side of the channel region, A first contact region located in the first region, and A second contact region located in the second region, The display device according to claim 1.

3. The opening of the substrate includes a first opening and a second opening, The first opening of the substrate overlaps the first contact region in a plane, The second opening of the substrate overlaps the second contact region in a plane, The display device according to claim 2.

4. The source electrode is electrically in contact with the upper surface of the first contact region, The drain electrode is electrically in contact with the upper surface of the second contact region, The display device according to claim 3.

5. The width of the first opening of the substrate and the width of the first contact region are the same in cross section, The width of the second opening of the substrate and the width of the second contact region are the same in cross section, The display device according to claim 3.

6. The resistance of the first contact region is lower than the resistance of the first region, The resistance of the second contact region is lower than the resistance of the second region, The display device according to claim 3.

7. Further includes an interlayer insulating film located between the semiconductor and the source electrode and between the semiconductor and the drain electrode, The interlayer insulating film includes A first opening overlapping the semiconductor and the source electrode in a plane, and A second opening overlapping the semiconductor and the drain electrode in a plane, The source electrode is electrically connected to the semiconductor through the first opening of the interlayer insulating film, The drain electrode is electrically connected to the semiconductor through the second opening of the interlayer insulating film, The display device according to claim 1.

8. The first opening and the second opening of the interlayer insulating film overlap the opening of the substrate in a plane, The display device according to claim 7.

9. The substrate includes a flexible material, The display device according to claim 1.

10. The display device according to claim 9, wherein the buffer layer fills the opening in the substrate.

11. Forming a substrate on a support substrate; Patterning the substrate to form an opening in the substrate; Forming a buffer layer on the substrate; Forming a semiconductor overlapping the opening of the substrate in a plane on the buffer layer; Forming a gate electrode overlapping the semiconductor in a plane; Forming a source electrode and a drain electrode electrically connected to the semiconductor; Forming a light-emitting element electrically connected to the drain electrode; and A method of manufacturing a display device, including irradiating a laser on the back surface of the support substrate to separate the substrate from the support substrate.

12. The semiconductor includes: A channel region overlapping the gate electrode in a plane; A first region located on one side of the channel region; A second region located on the other side of the channel region; A first contact region located in the first region; and A second contact region located in the second region. The method of manufacturing a display device according to claim 11.

13. The opening in the substrate includes a first opening and a second opening, The first opening in the substrate overlaps the first contact region in a plane, The second opening in the substrate overlaps the second contact region in a plane, The laser beam irradiated in the step of irradiating the laser passes through the first opening and the second opening of the substrate and reaches the first contact region and the second contact region. The method of manufacturing a display device according to claim 12.

14. The source electrode is electrically in contact with the upper surface of the first contact region, The drain electrode is electrically in contact with the upper surface of the second contact region. The method of manufacturing a display device according to claim 13.

15. The width of the first opening in the substrate and the width of the first contact region are the same in cross section, The width of the second opening in the substrate and the width of the second contact region are the same in cross section. The method of manufacturing a display device according to claim 13.

16. The resistance of the first contact region is lower than the resistance of the first region, The resistance of the second contact region is lower than the resistance of the second region. The method of manufacturing a display device according to claim 13.

17. After the step of forming the gate electrode, Forming an interlayer insulating film on the gate electrode; and Further including forming a first opening and a second opening in the interlayer insulating film, The source electrode and the drain electrode are located on the interlayer insulating film. The first opening of the interlayer insulating film overlaps the semiconductor and the source electrode in a plane. The second opening of the interlayer insulating film overlaps the semiconductor and the drain electrode in a plane. The source electrode is electrically connected to the semiconductor through the first opening of the interlayer insulating film. The drain electrode is electrically connected to the semiconductor through the second opening of the interlayer insulating film. The method for manufacturing a display device according to claim 11.

18. The first opening and the second opening of the interlayer insulating film overlap the opening of the substrate in a plane. The method for manufacturing a display device according to claim 17.

19. The support substrate includes a rigid material. The substrate includes a flexible material. The method for manufacturing a display device according to claim 11.

20. In the step of forming the buffer layer, The buffer layer fills the opening of the substrate. The method for manufacturing a display device according to claim 19.

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