Electrostatic chuck

Abstract

The utility model relates to an electrostatic chuck, which comprises a main body part, an electrode layer disposed on an upper portion of the main body; an insulating layer covering the electrode layer; and a plurality of protrusions disposed on the insulating layer so as to be spaced apart in one direction, respectively, and supporting a display substrate to be processed.

Description

Technical Field

[0001] This utility model relates to electrostatic chucks, and more specifically to electrostatic chucks used in the manufacture of display devices or semiconductor devices. Background Technology

[0002] In addition to the manufacturing of various semiconductor chips such as processors and memory, the manufacturing of display devices or panels used to manufacture flat panel display devices, such as organic light-emitting display devices, is also carried out in various process equipment or chambers.

[0003] In the manufacturing processes of semiconductor devices and display devices, chucks are used to hold wafers or substrates on a worktable. For example, chucks can include mechanical chucks that utilize clamps or vacuum to hold substrates on a worktable, as well as electric chucks that utilize electricity.

[0004] As a type of electric chuck, the electrostatic chuck can use electrostatic force to fix the substrate to the worktable, thus having the advantages of simplicity and strong adsorption force.

[0005] The aforementioned background technology is technical information possessed by the inventor for the purpose of deriving this utility model or technical information learned during the process of deriving this utility model, and is not necessarily common knowledge disclosed to the general public before the application of this utility model.

[0006] However, existing electrostatic chucks have the problem that the load is concentrated on the portion of the substrate that overlaps with the protrusion of the support substrate, which may cause cracks. Utility Model Content

[0007] The purpose of this invention is to provide an electrostatic chuck that can prevent cracking during the manufacturing process of a display device.

[0008] However, the above issues are illustrative, and the issues that this utility model aims to solve are not limited to these.

[0009] This utility model discloses an electrostatic chuck, comprising: a main body; an electrode layer disposed on the upper part of the main body; an insulating layer covering the electrode layer; and a plurality of protrusions disposed on the insulating layer and spaced apart in one direction to support a display substrate as the object to be processed.

[0010] In one embodiment, the electrostatic chuck may further include a through-hole penetrating the insulating layer to inject cooling material into the space between the display substrate and the insulating layer.

[0011] In one embodiment, the protrusion may include a groove that runs through the protrusion to communicate with the outside of the protrusion, and the interval between two adjacent protrusions among the plurality of protrusions is greater than 1.5 mm and less than 3 mm.

[0012] In one embodiment, the groove may be a straight groove when viewed in a plan view.

[0013] In one embodiment, the grooves may be two straight grooves that intersect each other when viewed in a plan view.

[0014] In one embodiment, the electrostatic chuck may further include a lid disposed on the upper part of the protrusion to cover the groove of the protrusion.

[0015] In one embodiment, the protrusion may have a hemispherical relief shape.

[0016] In one embodiment, the width of the protrusion may be greater than 0.1 mm and less than 1 mm.

[0017] In one embodiment, the protrusion may comprise the same material as the insulating layer.

[0018] In one embodiment, the height of the protrusion may be above 35 μm and below 45 μm.

[0019] In one embodiment, the electrostatic chuck may further include a dam portion configured on the insulating layer along the periphery of the body portion to surround the plurality of protrusions and support the display substrate.

[0020] In one embodiment, the height of the dam may be greater than the height of the protrusion.

[0021] In one embodiment, the dam portion may be formed as a closed loop along the periphery of the main body portion.

[0022] In one embodiment, the electrostatic chuck may further include a power supply unit that supplies DC power to the electrode layer.

[0023] In one embodiment, the display substrate and the electrode layer may be charged with different polarities.

[0024] In one embodiment, the display substrate and the electrode layer may be charged in a monopolar manner.

[0025] In one embodiment, the electrostatic chuck may further include a focusing ring configured to surround a portion of the body and the insulating layer.

[0026] Other aspects, features, and advantages beyond those described above will become clear from the following specific details, claims, and drawings used to implement the utility model.

[0027] (Utility Model Effect)

[0028] According to this invention, cracks can be prevented in an electrostatic chuck from being caused by the load being concentrated on the portion of the substrate that overlaps with the protrusion of the support substrate.

[0029] This allows for the creation of display devices with improved quality.

[0030] The effects of this utility model are not limited to those mentioned above. Those skilled in the art should be able to clearly understand other effects not mentioned from the description in the claims. Attached Figure Description

[0031] Figure 1 This is a schematic plan view of an embodiment of the electrostatic chuck of the present invention.

[0032] Figure 2 This is a schematic cross-sectional view illustrating an embodiment of the electrostatic chuck of the present invention.

[0033] Figure 3 This is a plan view showing an enlarged portion of an electrostatic chuck according to an embodiment of the present invention, which can correspond to... Figure 1 Part III.

[0034] Figure 4 This is an enlarged cross-sectional view showing a portion of an electrostatic chuck according to an embodiment of the present invention.

[0035] Figure 5 This is an enlarged cross-sectional view showing a portion of an electrostatic chuck according to other embodiments of the present invention.

[0036] Figure 6 This is a schematic plan view illustrating a display device manufactured using an electrostatic chuck according to an embodiment of the present invention.

[0037] Figure 7 This is a schematic cross-sectional view illustrating a display device manufactured using an electrostatic chuck according to an embodiment of the present invention, which can correspond to the view along... Figure 6 The cross-section of the display device is taken by the VII-VII' line.

[0038] Symbol explanation:

[0039] 1: Display device; 2: Electrostatic chuck; 100: Substrate; 510: Main body; 520: First insulating layer; 530: Electrode layer; 540: Second insulating layer; 550: Protrusion; 560: Dam; 570: Focusing ring; 580: Through hole; 590: Power supply. Detailed Implementation

[0040] This utility model can have various modifications and embodiments. Specific embodiments are illustrated in the accompanying drawings and described in detail herein. References and Appendix Figure 1 The effects, features, and methods of achieving these effects and features of the present invention will become clear from the detailed embodiments described below. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms.

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing the invention with reference to the accompanying drawings, the same or corresponding constituent elements will be given the same reference numerals and repeated descriptions of them will be omitted.

[0042] In the following embodiments, terms such as "first" and "second" are not limiting terms, but are used to distinguish one constituent element from other constituent elements.

[0043] In the following embodiments, singular expressions include multiple expressions unless the opposite meaning is explicitly stated in the text.

[0044] In the following embodiments, terms such as "including" or "having" should be understood as referring to the presence of features or constituent elements described in the specification, and do not preclude the additional possibility of more than one other feature or constituent element.

[0045] In the following embodiments, when a membrane, region, constituent element, or other part is located on or above other parts, this includes not only the case where it is directly located on other parts, but also the case where other membranes, regions, constituent elements, or other parts are present between them.

[0046] In the accompanying drawings, the sizes of the constituent elements may be enlarged or reduced for ease of explanation. For example, the sizes and thicknesses of the components shown are arbitrarily illustrated for ease of explanation, and the present invention is not necessarily limited to the situations shown in the drawings.

[0047] In the following embodiments, the x-axis, y-axis, and z-axis are not limited to the three axes of a Cartesian coordinate system, but can be interpreted to include their broader meaning. For example, the x-axis, y-axis, and z-axis can be orthogonal to each other, but can also refer to different directions that are not orthogonal to each other.

[0048] In cases where a particular embodiment can be implemented in different ways, a specific sequence of operations may also be performed differently than the sequence described. For example, two operations described consecutively may be performed substantially simultaneously, or they may be performed in the reverse order of the described sequence.

[0049] Figure 1 This is a schematic plan view of an embodiment of the electrostatic chuck of the present invention. Figure 2 This is a schematic cross-sectional view illustrating an embodiment of the electrostatic chuck of this utility model. Figure 2 For ease of explanation, the diagram shows a direction along a third party (e.g., Figure 1 , Figure 2 The state in which the display substrate DS is placed on the electrostatic chuck 2 (in the z direction, etc.).

[0050] Reference Figure 1 and Figure 2 The electrostatic chuck 2 can be used to clamp the display substrate DS. The display substrate DS can refer to the substrate 100 described later, which is being processed for manufacturing the display device 1 described later. For example, the display substrate DS can be a substrate on which at least one of an inorganic layer, an organic layer, and a metal layer has been deposited.

[0051] At this time, a display element including a transistor and an organic light-emitting diode can be disposed on the substrate 100. For example, the display element including a transistor and an organic light-emitting diode can be disposed on the substrate 100 using dry etching or plasma chemical vapor deposition (PCVD).

[0052] When transistors and organic light-emitting diodes are formed on substrate 100 using a dry etching process, the temperature of substrate 100 increases, which can lead to burns of the photosensitive material used in the process. Therefore, in order to prevent damage to the photosensitive material used in the dry etching process, a cooling fluid is filled into the lower part of substrate 100 to reduce the temperature of substrate 100 for the manufacturing process of display device 1.

[0053] At this time, an electrostatic chuck 2 can be arranged at the lower part of the substrate 100 to clamp the substrate 100 and the electrostatic chuck 2, thereby fixing the substrate 100 while preventing the cooling fluid filled to the lower part of the substrate 100 from leaking to the outside and causing the substrate 100 to warp.

[0054] In one embodiment, the electrostatic chuck 2 may include a main body 510, a first insulating layer 520, an electrode layer 530, a second insulating layer 540, a protrusion 550, and a dam 560.

[0055] The main body 510 is the portion that houses the constituent elements of the electrostatic chuck 2, and may include metal or ceramic. As one embodiment, the main body 510 may be formed in a single layer or multiple layers from 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), and may include metals selected from silicon oxide (SiO2) and silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO) x One or more inorganic insulators from the group consisting of zinc oxide (ZnO) x The zinc oxide (ZnO) and / or zinc peroxide (ZnO2) may be present. For example, the body portion 510 may include aluminum (Al) or aluminum oxide (Al2O3).

[0056] As one embodiment, the main body 510 can be modified to have a thickness of 30mm to 50mm, 40mm to 60mm, 20mm to 60mm, etc. For example, the main body 510 can have a thickness of 40mm to 50mm.

[0057] A first insulating layer 520 may be disposed on the main body portion 510. Specifically, the first insulating layer 520 may be disposed on the upper surface of the main body portion 510.

[0058] The first insulating layer 520 may include materials selected from silicon oxide (SiO2) and silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO) x One or more inorganic insulators from the group consisting of zinc oxide (ZnO) x The insulating layer 520 may be zinc oxide (ZnO) and / or zinc peroxide (ZnO2). For example, the first insulating layer 520 may include aluminum oxide (Al2O3).

[0059] As one embodiment, the first insulating layer 520 can be formed on the main body 510 using an atmospheric plasma spraying (APS) method. In this case, the first insulating layer 520 can be configured to have various thicknesses, such as 200 μm to 600 μm, 300 μm to 550 μm, and 250 μm to 500 μm. For example, the first insulating layer 520 can have a thickness of 300 μm to 500 μm.

[0060] An adhesive layer (not shown) may be disposed between the main body 510 and the first insulating layer 520. Typically, it may be difficult to apply the first insulating layer 520 directly to the main body 510 using an atmospheric plasma spraying (APS) method.

[0061] For this purpose, an adhesive layer may be disposed between the main body 510 and the first insulating layer 520. The adhesive layer may include one or more metals or alloys thereof 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). For example, the adhesive layer may include a nickel-aluminum (Ni-Al) alloy.

[0062] The adhesive layer can be deformed in various ways, such as having a thickness of 30μm to 70μm, 40μm to 70μm, or 30μm to 60μm. For example, the adhesive layer can have a thickness of 40μm to 60μm.

[0063] An electrode layer 530 may be disposed on the first insulating layer 520. The upper surface of the electrode layer 530 may be spaced apart from one side of the opposing substrate 100 by a certain distance.

[0064] The electrode layer 530 can be formed as a single layer or multiple layers from 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). For example, the electrode layer 530 can be formed from tungsten (W).

[0065] The electrode layer 530 can be applied to the first insulating layer 520 using atmospheric plasma spraying (APS). The electrode layer 530 can be configured with various thicknesses, such as 5 μm to 45 μm, 10 μm to 45 μm, and 5 μm to 40 μm. For example, the electrode layer 530 can have a thickness of 20 μm to 30 μm.

[0066] A second insulating layer 540 may be disposed on the electrode layer 530. Specifically, the second insulating layer 540 may be disposed on the electrode layer 530, thereby being configured to completely cover the electrode layer 530. The second insulating layer 540 may include materials selected from silicon oxide (SiO2) and silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO) x One or more inorganic insulators from the group consisting of zinc oxide (ZnO) x The insulating layer 540 can be zinc oxide (ZnO) and / or zinc peroxide (ZnO2). For example, the second insulating layer 540 can include aluminum oxide (Al2O3). As an embodiment, the second insulating layer 540 can be formed on the electrode layer 530 using an atmospheric plasma spraying (APS) method. The second insulating layer 540 can include the same material as the first insulating layer 520. Furthermore, the upper surface of the second insulating layer 540 can have a flat shape.

[0067] The second insulating layer 540 can be configured to have various thicknesses, such as 100 μm to 500 μm, 150 μm to 600 μm, and 200 μm to 600 μm. For example, the second insulating layer 540 can have a thickness of 100 μm to 350 μm.

[0068] The upper surface of the second insulating layer 540 and the lower surface of the display substrate DS may be at least partially spaced apart so that a cooling material for cooling the display substrate DS can be filled between the second insulating layer 540 and the display substrate DS. This creates an empty space between the second insulating layer 540 and the display substrate DS. For example, the cooling material for cooling the display substrate DS between the second insulating layer 540 and the display substrate DS may be a gas. In particular, the cooling material for cooling the display substrate DS between the second insulating layer 540 and the display substrate DS may be helium.

[0069] A dam 560 may be disposed on the second insulating layer 540. The dam 560 may be disposed along the periphery of the main body 510. In one embodiment, the dam 560 may be disposed in a closed loop along the periphery of the main body 510. The dam 560 serves to seal the gas between the second insulating layer 540 and the display substrate DS, preventing the gas used to cool the display substrate DS from leaking to the outside. For this purpose, the dam 560 may be disposed on the second insulating layer 540, and the upper surface of the dam 560 may be in direct contact with the lower surface of the display substrate DS. As one embodiment, the dam 560 may be formed using an atmospheric plasma spraying (APS) method. For example, the dam 560 may comprise the same material as the second insulating layer 540 and may be formed using the same process as the second insulating layer 540.

[0070] Protrusions 550 may also be disposed on the second insulating layer 540. Multiple protrusions 550 may be provided, and the multiple protrusions 550 may be configured to be surrounded by a dam 560. That is, multiple protrusions 550 may be disposed within the internal region of the dam 560 forming a closed loop. In one embodiment, the protrusions 550 may include materials selected from silicon oxide (SiO2) and silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2), and zinc oxide (ZnO) x One or more inorganic insulators from the group consisting of zinc oxide (ZnO) x The protrusion 550 can be zinc oxide (ZnO) and / or zinc peroxide (ZnO2). For example, the protrusion 550 can include aluminum oxide (Al2O3). As an embodiment, the protrusion 550 can be formed on the second insulating layer 540 using an atmospheric plasma spraying (APS) method. The protrusion 550 can include the same material as the second insulating layer 540. Furthermore, the protrusion 550 can be formed by the same process as the second insulating layer 540.

[0071] As one embodiment, the electrostatic chuck 2 may include a focus ring 570 for protecting the electrostatic chuck 2 from the outside. Specifically, the focus ring 570 may be configured to surround a portion of the main body 510, a first insulating layer 520, and a second insulating layer 540.

[0072] Furthermore, a through-hole 580 may be provided to fill the space between the electrostatic chuck 2 and the display substrate DS with gas for cooling the display substrate DS. Specifically, the electrostatic chuck 2 may include a through-hole 580 penetrating the main body 510, the first insulating layer 520, the electrode layer 530, and the second insulating layer 540 to fill the empty space formed between the second insulating layer 540 and the display substrate DS with helium (He) gas for cooling the display substrate DS. Figure 2 The illustration shows an electrostatic chuck 2 with a single through hole 580, but the present invention is not limited thereto. In other embodiments, multiple through holes 580 may be provided.

[0073] In one embodiment, the electrostatic chuck 2 may further include a power supply unit 590 that supplies DC power to the electrode layer 530. Specifically, the electrode layer 530 receives DC power from the power supply unit 590 via a power supply line 591. A variable capacitor 592 may be provided between the power supply unit 590 and the electrode layer 530. By adjusting the capacitance value of the variable capacitor 592 provided between the power supply unit 590 and the electrode layer 530, the force with which the electrode layer 530 clamps the display substrate DS can be adjusted.

[0074] Furthermore, in one embodiment of this invention, the electrostatic chuck 2 can be charged in a monopolar manner. When DC power is supplied to the electrode layer 530 via the power supply unit 590, the electrode layer 530 can be charged, for example, with a positive polarity. Since plasma used during the manufacturing process of the display device within the equipment or cavity can generate and contain both positive and negative charges, when DC power is supplied to the electrode layer 530 via the power supply unit 590 and the electrode layer 530 is charged with a positive polarity, the display substrate DS can be charged with a negative polarity, opposite to the positive polarity, due to the negative charges present within the equipment or cavity. This allows a clamping force to act between the electrostatic chuck 2 and the display substrate DS. Thus, through the clamping force generated between the electrostatic chuck 2 and the display substrate DS, the display substrate DS can be fixed to the electrostatic chuck 2, while preventing the display substrate DS from warping due to leakage of cooling gas between the electrostatic chuck 2 and the display substrate DS to the outside.

[0075] Figure 3 This is a plan view showing an enlarged portion of an electrostatic chuck according to an embodiment of the present invention, which can correspond to... Figure 1 Part III. Figure 4 This is an enlarged cross-sectional view showing a portion of an electrostatic chuck according to an embodiment of the present invention. Figure 4 For ease of explanation, the state in which the display substrate DS is placed on the electrostatic chuck 2 is shown.

[0076] Reference Figure 3 and Figure 4 The protrusions 550 on the second insulating layer 540 can be provided in multiple ways, and the multiple protrusions 550 can be configured to be surrounded by the dam portion 560. That is, multiple protrusions 550 can be provided in the internal region of the dam portion 560 forming a closed loop.

[0077] In one embodiment, the protrusion 550 may have a hemispherical relief shape. The protrusion 550 may contact and support the display substrate DS, while providing space for cooling gas to form convection under the display substrate DS. That is, cooling gas (e.g., helium) is supplied to the space between the protrusions 550 to form convection.

[0078] At this point, the display substrate DS can contact the protrusion 550, thereby distributing the load of the display substrate DS to the protrusion 550 and allowing it to be supported by the protrusion 550. Therefore, the total contact area between the protrusion 550 and the display substrate DS can be related to the surface pressure acting on the display substrate DS. Specifically, when a relatively small number of protrusions 550 support the display substrate DS, the surface pressure may concentrate on the portion of the display substrate DS that contacts the corresponding protrusion 550. This may induce microcracks in the display substrate DS.

[0079] Therefore, the larger the total contact area between the protrusion 550 and the display substrate DS, the less concentrated the load on the display substrate DS will be in a specific part, and the load can be distributed more evenly.

[0080] In one embodiment, the plurality of protrusions 550 may be configured in a first direction (e.g., Figure 1 , Figure 3 The protrusions 550 are spaced apart from each other in a second direction (e.g., in the x-direction). Furthermore, the plurality of protrusions 550 can be configured to be spaced apart in a second direction intersecting the first direction (e.g., in the x-direction). Figure 1 , Figure 3 They are also spaced apart from each other in the y-direction (e.g., the protrusions 550). In other words, it can be said that the multiple protrusions 550 are configured in a lattice pattern.

[0081] At this time, the plurality of protrusions 550 can be spaced apart with a constant interval between them. In one embodiment, the interval PD between two adjacent protrusions 550 can be 1.5 mm or more and 3 mm or less. For example, the interval PD between two adjacent protrusions 550 can be 2 mm. In this case, it can be said that the plurality of protrusions 550 are spaced apart with an interval PD in a first direction and also spaced apart with the same interval PD in a second direction. At this time, as an embodiment, the width W of the protrusions 550 can be 0.1 mm or more and 1 mm or less.

[0082] However, this invention is not limited to this. In other embodiments, the plurality of protrusions 550 may be spaced apart in a first direction with a first interval PD1 and spaced apart in a second direction with a second interval PD2. In this case, the first interval PD1 may be different from the second interval PD2, and may be 1.5 mm or more and 3 mm or less, respectively. Hereinafter, for ease of explanation, the description will focus on the case where the plurality of protrusions 550 have the same interval PD in the first and second directions.

[0083] Furthermore, in one embodiment, the height of the protrusion 550 can be 35 μm or more and 45 μm or less, for example, 40 μm. The protrusion 550 supports the display substrate DS, therefore the distance between the second insulating layer 540 where the protrusion 550 is disposed and the display substrate DS can be 35 μm or more and 45 μm or less, for example, 40 μm. The height of the protrusion 550 provides space for the convection of cooling gas. Furthermore, in this case, the height of the dam 560 can be greater than the height of the protrusion 550. This allows for a more complete sealing of the space between the display substrate DS and the second insulating layer 540.

[0084] As described above, according to one embodiment of the present invention, the spacing PD between the protrusions 550 can be 1.5 mm or more and 3 mm or less, for example, it can be formed as 2 mm, thereby improving the surface pressure strength of the display substrate DS. For example, if the spacing PD between the protrusions 550 is greater than 3 mm, the number of protrusions 550 disposed on the second insulating layer 540 to support the display substrate DS may be insufficient. As a result, the contact area between the protrusions 550 and the display substrate DS may also be insufficient, and the surface pressure may concentrate on the portion of the display substrate DS in contact with the protrusions 550. Furthermore, if the spacing PD between the protrusions 550 is less than 1.5 mm, the convection of cooling gas cannot be smooth in the space between the protrusions 550, thereby failing to achieve effective cooling.

[0085] In one embodiment, the protrusion 550 may include a groove GV. Specifically, the protrusion 550 may include a groove GV that runs through the protrusion 550 to allow the protrusion 550 to communicate with the outside. In one embodiment, as... Figure 3 As shown, the slot GV can be included in the first direction (e.g., Figure 1 , Figure 3 The first groove GV1 extends in the x-direction (e.g., the first direction) and in the second direction intersecting the first direction (e.g., the second direction). Figure 1 , Figure 3The first groove GV1 and the second groove GV2 extend in the y-direction (e.g., the direction of the groove). The first groove GV1 and the second groove GV2 can be, for example, straight grooves. In other words, when viewed in a plan view, the groove GV can have a "+" shape. Furthermore, the protrusion 550 can be divided into four parts by the groove GV. However, the present invention is not limited to this; in other embodiments, the groove GV can be a groove extending in one direction. In this case, the groove GV can have a "-" shape. Furthermore, the protrusion 550 can be divided into two parts by the groove GV.

[0086] With the protrusion 550 having a groove GV traversing the protrusion 550, the convection of cooling gas supplied between the second insulating layer 540 and the display substrate DS becomes smoother, enabling more efficient heat exchange. As mentioned earlier, as the spacing PD between the protrusions 550 narrows, more protrusions 550 can be configured to support the display substrate DS, thereby preventing surface pressure concentration in the portion of the display substrate DS in contact with the protrusions 550 and dispersing the surface pressure. In this case, the cooling fluid cannot reach the portion of the display substrate DS in contact with the protrusions 550, so as the number of protrusions 550 increases, the temperature of the display substrate DS may become uneven. According to one embodiment of the present invention, the cooling fluid can also convect smoothly in the area where the protrusions 550 are configured through the groove GV of the protrusion 550. Therefore, the electrostatic chuck 2 can achieve smooth cooling while preventing surface pressure concentration in the display substrate DS.

[0087] Figure 5 This is an enlarged cross-sectional view showing a portion of an electrostatic chuck according to other embodiments of the present invention. Figure 5 For ease of explanation, the diagram shows a state where the display substrate DS is mounted on the electrostatic chuck 2. The electrostatic chuck 2 in this embodiment is similar to that in the aforementioned embodiments; therefore, the following description focuses on the differences.

[0088] Reference Figure 5As previously described, the protrusion 550 may include a groove GV that runs through the protrusion 550 to allow the protrusion 550 to communicate with the outside. In this case, the groove GV may be in a "+" or "-" shape when viewed in a plan view. Furthermore, the electrostatic chuck 2 may also include lids 555. The number of lids 555 may correspond to the number of protrusions 550. The lids 555 may be disposed on the upper part of each of the multiple protrusions 550 to cover each of the multiple protrusions 550. The lids 555 may cover the groove GV and may contact the display substrate DS to support the display substrate DS. Thus, the load on the display substrate DS can be easily distributed through the protrusions 550 and the lids 555 above the protrusions 550. Furthermore, cooling gas can be convected through the groove GV disposed below the lids 555 and penetrating the protrusions 550, thus smoothly cooling the portion of the display substrate DS in contact with the lids 555.

[0089] Figure 6 This is a schematic plan view illustrating a display device manufactured using an electrostatic chuck according to an embodiment of the present invention.

[0090] Reference Figure 6 A display device 1 manufactured according to an embodiment of the present invention may include a display area DA and a peripheral area PA located outside the display area DA. The display device 1 can provide an image by means of an array of multiple pixels PX arranged in two dimensions in the display area DA.

[0091] The peripheral area PA is the area that does not provide an image and can surround all or part of the display area DA. Drivers for providing electrical signals or power to the pixel circuits corresponding to each pixel PX can be configured in the peripheral area PA. Pads can also be configured in the peripheral area PA as areas capable of electrical connection to electronic components or printed circuit boards.

[0092] The following describes the case where the display device 1 includes an Organic Light Emitting Diode (OLED) as the light emitting element; however, the display device 1 of this invention is not limited to this. As another embodiment, the display device 1 may be a light-emitting display device including an inorganic light-emitting diode (i.e., an inorganic light-emitting display). An inorganic light-emitting diode may include a PN junction diode containing a material based on an inorganic semiconductor. When a voltage is applied forward to the PN junction diode, holes and electrons are injected, and the energy generated by the recombination of these holes and electrons is converted into light energy, thereby emitting light of a predetermined color. The aforementioned inorganic light-emitting diode may have a width of several micrometers to several hundred micrometers; in some embodiments, the inorganic light-emitting diode may be referred to as a micro LED. As yet another embodiment, the display device 1 may be a quantum dot light-emitting display.

[0093] On the other hand, the display device 1 can be used not only as a display screen for portable electronic devices such as mobile phones, smartphones, tablet PCs, mobile communication terminals, electronic manuals, e-books, PMPs (portable multimedia players), navigators, and UMPCs (Ultra Mobile PCs), but also as a display screen for various products such as televisions, laptops, monitors, billboards, and Internet of Things (IoT) devices. Furthermore, the display device 1 according to one embodiment can be used in wearable devices such as smartwatches, watch phones, glasses-type displays, and head-mounted displays (HMDs). Additionally, the display device 1 according to one embodiment can be used as a car dashboard, a car center fascia, or a CID (Center Information Display) located on the dashboard, an interior mirror display replacing the car's rearview mirror, or a display screen located on the back of the front seats as a rear-seat entertainment device for the car.

[0094] Figure 7This is a schematic cross-sectional view illustrating a display device manufactured using an electrostatic chuck according to an embodiment of the present invention, which can correspond to the view along... Figure 6 The cross-section of the display device is taken by the VII-VII' line.

[0095] Reference Figure 7 The display device 1 may include a stacked structure of a substrate 100, a pixel circuit layer PCL, a display element layer DEL, and an encapsulation layer 300. The aforementioned display substrate DS (refer to...) Figure 1 It can be a configuration that is in the manufacturing process of the display device 1, for example, that any one of the pixel circuit layer PCL, display element layer DEL and encapsulation layer 300 is stacked on the substrate 100.

[0096] The substrate 100 may be a multilayer structure comprising a base layer containing a polymer resin and an inorganic layer. For example, the substrate 100 may include a base layer containing a polymer resin and a barrier layer as an inorganic insulating layer. For example, the substrate 100 may include a first base layer 101, a first barrier layer 102, a second base layer 103, and a second barrier layer 104 stacked sequentially. The first base layer 101 and the second base layer 103 may include polyimide (PI), polyethersulfone (PES), polyarylate, polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polycarbonate (PC), cellulose triacetate (TAC), and / or cellulose acetate propionate (CAP), etc. The first barrier layer 102 and the second barrier layer 104 may include inorganic insulators such as silicon oxide, silicon oxide nitride, and / or silicon nitride. The substrate 100 may have flexible properties.

[0097] A pixel circuit layer PCL is disposed on the substrate 100. Figure 7 The illustration shows a pixel circuit layer PCL comprising a transistor TFT and a buffer layer 111, a first gate insulating layer 112, a second gate insulating layer 113, an interlayer insulating layer 114, a first planarization insulating layer 115, and a second planarization insulating layer 116 disposed below and / or above the constituent elements of the transistor TFT.

[0098] The buffer layer 111 can reduce or block the penetration of foreign matter, moisture or external gases from the lower part of the substrate 100, and can provide a flat surface on the substrate 100. The buffer layer 111 may include inorganic insulating materials such as silicon oxide, silicon oxide nitride, and silicon nitride, and may be formed from a single-layer structure or a multi-layer structure including the aforementioned materials.

[0099] The transistor TFT on the buffer layer 111 may include a semiconductor layer Act, which may include polycrystalline silicon. Alternatively, the semiconductor layer Act may include amorphous silicon, oxide semiconductor, or organic semiconductor, etc. The semiconductor layer Act may include a channel region C and a drain region D and a source region S respectively disposed on both sides of the channel region C. The gate electrode GE may overlap with the channel region C.

[0100] The gate electrode GE may include a low-resistance metallic material. The gate electrode GE may include a conductive material containing molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), etc., and may be formed from multiple layers or a single layer of the above-mentioned materials.

[0101] The first gate insulating layer 112 between the semiconductor layer Act and the gate electrode GE may include, for example, silicon oxide (SiO2) or silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2) or zinc oxide (ZnO) x Inorganic insulating materials such as zinc oxide (ZnO) are used. x It can be zinc oxide (ZnO) and / or zinc peroxide (ZnO2).

[0102] The second gate insulating layer 113 can be configured to cover the gate electrode GE. The second gate insulating layer 113 can be similar to the first gate insulating layer 112, comprising materials such as silicon oxide (SiO2) or silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2) or zinc oxide (ZnO) x Inorganic insulating materials such as zinc oxide (ZnO) are used. x It can be zinc oxide (ZnO) and / or zinc peroxide (ZnO2).

[0103] In one embodiment, the first gate insulating layer 112 and / or the second gate insulating layer 113 may include a recessed region (not shown). The following description focuses on the first gate insulating layer 112, but this description can also be applied similarly to the second gate insulating layer 113.

[0104] A recessed region can refer to a portion of the first gate insulating layer 112 that is formed as a recess and is thinner than other portions. In one embodiment, the thickness of the first gate insulating layer 112 in the recessed region can be 13 to 15 angstroms (e.g., 14 angstroms) thinner than the thickness of the first gate insulating layer 112 in the regions outside the recessed region. In one embodiment, such recessed regions can be provided in multiple locations and configured in the first gate insulating layer 112 in a first direction (e.g., ...). Figure 7 The x-direction) and the second direction intersecting the first direction (e.g., the ... Figure 7 The recessed areas are spaced apart from each other in the y-direction. In other words, the recessed areas can be described as being configured in a lattice pattern.

[0105] At this point, the recessed areas can be spaced apart with a constant interval between them. In one embodiment, the interval between two adjacent recessed areas among the plurality of recessed areas can be greater than 1.5 mm and less than 3 mm. For example, the interval between two adjacent recessed areas among the plurality of recessed areas can be 2 mm. In this case, it can be said that the plurality of recessed areas can be spaced apart in a first direction and also spaced apart in a second direction with the same interval.

[0106] The recessed area described above can be formed during the manufacturing process of the display device 1 using the aforementioned electrostatic chuck 2. As previously mentioned, in the electrostatic chuck 2 (refer to...) Figure 3 The protrusion 550 (refer to) Figure 3 A display substrate DS is mounted on the protrusion 550, and the first gate insulating layer 112 is etched. At this time, the etch rate of the area of ​​the display substrate DS that contacts the protrusion 550 can be increased, thereby forming a recessed area in the first gate insulating layer 112 with a thickness smaller than that of the periphery.

[0107] An upper electrode Cst2 of the energy storage capacitor Cst can be disposed on the upper part of the second gate insulating layer 113. The upper electrode Cst2 can overlap with the gate electrode GE below it. At this time, the gate electrode GE and the upper electrode Cst2, which overlap and sandwich the second gate insulating layer 113, can form the energy storage capacitor Cst. That is, the gate electrode GE can function as the lower electrode Cst1 of the energy storage capacitor Cst.

[0108] As described above, the energy storage capacitor Cst and the transistor TFT can be formed overlappingly. In some embodiments, the energy storage capacitor Cst can also be formed without overlapping with the transistor TFT.

[0109] The upper electrode Cst2 may include aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W) and / or copper (Cu), and may be a single layer or multiple layers of the aforementioned materials.

[0110] The interlayer insulating layer 114 may cover the upper electrode Cst2. The interlayer insulating layer 114 may include silicon oxide (SiO2) or silicon nitride (SiN). x ), silicon nitride oxide (SiON), aluminum oxide (Al2O3), titanium oxide (TiO2), tantalum oxide (Ta2O5), hafnium oxide (HfO2) or zinc oxide (ZnO) x Zinc oxide (ZnO), etc. x The interlayer insulation layer 114 can be a single layer or multiple layers including the aforementioned inorganic insulation material.

[0111] The drain electrode DE and source electrode SE can be located on the interlayer insulating layer 114. The drain electrode DE and source electrode SE can be connected to the drain region D and source region S respectively through contact holes formed in the insulating layer beneath them. The drain electrode DE and source electrode SE can include materials with excellent conductivity. The drain electrode DE and source electrode SE can include conductive materials containing molybdenum (Mo), aluminum (Al), copper (Cu), titanium (Ti), etc., and can be formed from multiple layers or a single layer comprising the aforementioned materials. As an embodiment, the drain electrode DE and source electrode SE can have a Ti / Al / Ti multilayer structure.

[0112] The first planarization insulating layer 115 may cover the drain electrode DE and the source electrode SE. The first planarization insulating layer 115 may include general-purpose polymers such as polymethyl methacrylate (PMMA) or polystyrene (PS), polymer derivatives with phenolic groups, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluorine polymers, p-xylene polymers, vinyl alcohol polymers, and mixtures thereof, such as organic insulating materials.

[0113] The second planarization insulating layer 116 may be disposed on the first planarization insulating layer 115. The second planarization insulating layer 116 may include the same material as the first planarization insulating layer 115, and may include general-purpose polymers such as polymethyl methacrylate (PMMA) or polystyrene (PS), phenolic polymer derivatives, acrylic polymers, imide polymers, aryl ether polymers, amide polymers, fluorinated polymers, p-xylene polymers, vinyl alcohol polymers, and mixtures thereof, such as organic insulating materials.

[0114] A display element layer (DEL) can be configured on the pixel circuit layer (PCL) of the aforementioned structure. The display element layer (DEL) may include an organic light-emitting diode (OLED) as a display element (i.e., a light-emitting element) and a pixel defining film 117. The OLED may include a stacked structure of a pixel electrode 210, an intermediate layer 220, and a common electrode 230. The OLED can emit light, for example, red, green, or blue light, or it can emit red, green, blue, or white light. The OLED can emit light through a light-emitting region, which can be defined as a pixel (PX).

[0115] The pixel electrode 210 of the organic light-emitting diode OLED can be electrically connected to the transistor TFT through contact holes formed in the second planarization insulating layer 116 and the first planarization insulating layer 115 and contact metal CM disposed on the first planarization insulating layer 115.

[0116] Pixel electrode 210 may include, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO). x Conductive oxides such as zinc oxide, indium oxide (In2O3), indium gallium oxide (IGO), or aluminum zinc oxide (AZO) are used. As another embodiment, the pixel electrode 210 may include a reflective film containing silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), or compounds thereof. As another embodiment, the pixel electrode 210 may also include a film formed of ITO, IZO, ZnO, or In2O3 above / below the aforementioned reflective film.

[0117] A pixel definition film 117 having an opening 117OP exposing the central portion of the pixel electrode 210 is disposed on the pixel electrode 210. The pixel definition film 117 may include organic and / or inorganic insulating materials. The opening 117OP may define the light-emitting region from which light is emitted from the organic light-emitting diode (OLED). For example, the size / width of the opening 117OP may correspond to the size / width of the light-emitting region. Therefore, the size and / or width of the pixel PX may depend on the size and / or width of the opening 117OP of the corresponding pixel definition film 117.

[0118] The intermediate layer 220 may include a light-emitting layer 222 formed corresponding to the pixel electrode 210. The light-emitting layer 222 may include a high-molecular-weight organic material or a low-molecular-weight organic material that emits light of a predetermined color. Alternatively, the light-emitting layer 222 may include an inorganic light-emitting material or include quantum dots.

[0119] As one embodiment, the intermediate layer 220 may include a first functional layer 221 and a second functional layer 223 respectively disposed below and above the light-emitting layer 222. The first functional layer 221 may, for example, include a hole transport layer (HTL) or a hole transport layer and a hole injection layer (HIL). The second functional layer 223 may include an electron transport layer (ETL) and / or an electron injection layer (EIL) as constituent elements disposed above the light-emitting layer 222. The first functional layer 221 and / or the second functional layer 223 may, like the common electrode 230 described later, be formed as a common layer covering the entire substrate 100.

[0120] The common electrode 230 can be disposed on and overlapped with the pixel electrode 210. The common electrode 230 can be formed of a conductive material with a low work function. For example, the common electrode 230 may 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 alloys thereof. Alternatively, the common electrode 230 may also include a layer formed of ITO, IZO, ZnO, or In2O3 on the (semi-)transparent layer containing the aforementioned materials. The common electrode 230 can be formed integrally to cover the entire substrate 100.

[0121] The encapsulation layer 300 can be disposed on and cover the display element layer DEL. The encapsulation layer 300 may include at least one inorganic encapsulation layer and at least one organic encapsulation layer. As one embodiment, Figure 7The illustration shows a case where the encapsulation layer 300 includes a first inorganic encapsulation layer 310, an organic encapsulation layer 320, and a second inorganic encapsulation layer 330 stacked sequentially.

[0122] The first inorganic encapsulation layer 310 and the second inorganic encapsulation layer 330 may include one or more inorganic materials selected from aluminum oxide, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, silicon oxide, silicon nitride, and silicon nitride. The organic encapsulation layer 320 may include a polymer-based material. Polymer-based materials may include acrylic resins, epoxy resins, polyimide resins, and polyethylene resins, etc. As an embodiment, the organic encapsulation layer 320 may include an acrylate resin. The organic encapsulation layer 320 may be formed by curing monomers or coating polymers. The organic encapsulation layer 320 may be transparent.

[0123] Although not illustrated, a touch sensor layer can be configured on the encapsulation layer 300, and an optical functional layer can be configured on the touch sensor layer. The touch sensor layer can receive external input (e.g., coordinate information related to a touch event). The optical functional layer can reduce the reflectivity of light incident from the outside toward the display device 1 (external light), and / or can improve the color purity of light emitted from the display device 1. As one embodiment, the optical functional layer may include a phase retarder and / or a polarizer. The phase retarder may be a film type or a liquid crystal coating type, and may include a λ / 2 phase retarder and / or a λ / 4 phase retarder. The polarizer may also be a film type or a liquid crystal coating type. The film type may include an extended synthetic resin film, and the liquid crystal coating type may include liquid crystals arranged in a predetermined pattern. The phase retarder and polarizer may also include a protective film.

[0124] An adhesive component may be disposed between the touch sensor layer and the optical functional layer. The adhesive component may be made of any commonly known material in the art. The adhesive component may be a pressure-sensitive adhesive (PSA).

[0125] As described above, the present invention has been illustrated with reference to the illustrated embodiments, but these are merely examples. Those skilled in the art will fully understand that various modifications and equivalent embodiments can be implemented from the embodiments. Therefore, the true scope of protection of the present invention should be determined based on the claims.

Claims

1. An electrostatic chuck, comprising: Comprise: a main body portion; an electrode layer disposed on an upper portion of the main body portion; an insulating layer covering the electrode layer; and a plurality of protruding portions disposed on the insulating layer so as to be spaced apart in a direction, supporting a display substrate as a processing target, a spacing between two adjacent protruding portions among the plurality of protruding portions is 1.5 mm or more and 3 mm or less.

2. The electrostatic chuck according to claim 1, wherein the protruding portion includes a groove that traverses the protruding portion so as to communicate with an outside of the protruding portion.

3. The electrostatic chuck according to claim 2, wherein the groove is a straight groove when viewed in plan view.

4. The electrostatic chuck according to claim 2, wherein the groove is two straight grooves that cross each other when viewed in plan view.

5. The electrostatic chuck according to claim 2, further comprising: a cover portion disposed on an upper portion of the protruding portion so as to cover the groove of the protruding portion.

6. The electrostatic chuck according to claim 1, wherein the protruding portion has a hemispherical relief shape.

7. The electrostatic chuck according to claim 1, wherein a width of the protruding portion is 0.1 mm or more and 1 mm or less.

8. The electrostatic chuck according to claim 1, further comprising: a focus ring configured to surround a portion of the main body portion and the insulating layer.

9. The electrostatic chuck according to claim 1, wherein a height of the protruding portion is 35 μm or more and 45 μm or less.

10. The electrostatic chuck according to claim 1, further comprising: a dam portion disposed on the insulating layer so as to surround the plurality of protruding portions along a periphery of the main body portion, supporting the display substrate, a height of the dam portion is greater than a height of the protruding portion. ​

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