electrostatic chuck

Abstract

The present invention relates to an electrostatic chuck with a cooling structure utilizing cooling gas, comprising: an electrostatic chuck plate including a plurality of first cooling gas holes formed in a first region and a plurality of second cooling gas holes formed in a second region; and a substrate having a first flow path pattern connected to the plurality of first cooling gas holes, a second flow path pattern connected to the plurality of second cooling gas holes, and an inlet movement pattern for changing the inlet position of cooling gas injected into the first flow path pattern.

Description

Technical Field

[0001] This invention relates to electrostatic chucks, and more particularly, to an electrostatic chuck having a cooling structure utilizing cooling gas. Background Technology

[0002] Generally, semiconductor devices and display devices are manufactured by patterning multiple thin film layers, including dielectric and metal layers, sequentially stacked on a glass substrate, flexible substrate, or semiconductor wafer substrate. These thin film layers are sequentially deposited on the substrate through chemical vapor deposition (CVD) or physical vapor deposition (PVD) processes.

[0003] In chamber devices used to perform these semiconductor processes, electrostatic chucks (ESCs) are provided to support various substrates such as glass substrates, flexible substrates, and semiconductor wafer substrates, and in particular, to fix the corresponding substrates using electrostatic force. Typically, an ESC consists of a substrate and an ESC plate (eSC structure) disposed on top of the substrate. The ESC plate, as a multilayer structure performing the function of the ESC, includes an insulating layer, an electrode layer on the insulating layer, and a dielectric layer on the electrode layer. Furthermore, the ESC has a cooling structure for uniformly cooling the substrate inside the chamber using an external cooling gas (e.g., helium (He)).

[0004] Figure 1 This diagram shows the cooling structure of electrostatic chucks using conventional technology. That is, Figure 1 (a) is a diagram showing the shape of the cooling path pattern formed on the substrate as viewed from above. Figure 1 (b) shows along Figure 1 Figure (a) shows the cross-sectional shape of the electrostatic chuck cut off by line A-A'.

[0005] like Figure 1 As shown in (a) and (b), the conventional electrostatic chuck 1 is composed of a substrate having a plurality of first cooling gas holes 11, 21 and an electrostatic chuck plate having a plurality of second cooling gas holes 12, 22. The first cooling gas holes 11, 21 formed in the substrate are holes for cooling gas to flow in from an external supply device (not shown in the figure), and the second cooling gas holes 12, 22 formed in the electrostatic chuck plate are holes for cooling gas inside the electrostatic chuck 1 to be released toward the substrate (not shown in the figure).

[0006] A cooling flow path pattern is formed on the surface of the substrate to uniformly diffuse cooling gas flowing in from the outside in a horizontal direction. This cooling flow path pattern consists of an outer flow path pattern 10 for diffusing cooling gas to an outer region on the substrate and an inner flow path pattern 20 for diffusing cooling gas to an inner region on the substrate. The outer flow path pattern 10 is configured to connect to a first cooling gas hole 11 and a plurality of second cooling gas holes 12. The inner flow path pattern 20 is configured to connect to a plurality of first cooling gas holes (HeInlet) 21 and a plurality of second cooling gas holes (HeOutlet) 22 arranged in a predetermined pattern.

[0007] However, in conventional electrostatic chucks 1, there is only one first cooling gas hole 11 connected to the external flow path pattern 10, located in the outer edge region of the corresponding pattern 10. Due to this problem, uneven cooling gas release to the substrate inevitably occurs. For example, the density of cooling gas released from the second cooling gas hole 12 located farther from the first cooling gas hole 11 is relatively low, while the density of cooling gas released from the second cooling gas hole 12 located closer to the first cooling gas hole 11 is relatively high.

[0008] In addition, the process gas in the plasma state inside the chamber passes through the multiple second cooling gas holes 12, 22 formed by the electrostatic chuck plate and reacts with the metal material of the substrate, thus causing the problem of frequent plasma discharge (or arcing) phenomena occurring around the multiple second cooling gas holes 12, 22.

[0009] Thus, the conventional electrostatic chuck 1, with its asymmetrical configuration of the first cooling gas hole 11 connected to the external flow path pattern 10 and the non-insulating structure around the plurality of second cooling gas holes 12, 22, results in uneven cooling gas density discharged to the substrate, thereby causing various semiconductor process problems such as plasma discharge, PR burning, and under etching. Summary of the Invention

[0010] The purpose of this invention is to solve the above-mentioned problems and other issues. Another purpose is to provide an electrostatic chuck for improving plasma discharge phenomena.

[0011] Another objective is to provide an electrostatic chuck that provides a uniform density of cooling gas discharged onto a substrate.

[0012] Another objective is to provide an electrostatic chuck with a new cooling flow pattern.

[0013] Another objective is to provide an electrostatic chuck with an optimal number of cooling gas holes relative to the cross-sectional area of ​​the cooling flow path.

[0014] Another objective is to provide an electrostatic chuck with an insulating structure around the periphery of a plurality of cooling gas holes formed in the electrostatic chuck plate.

[0015] To achieve the aforementioned or other objectives, according to one aspect of the present invention, an electrostatic chuck is provided, comprising: an electrostatic chuck plate including a plurality of first cooling gas holes formed in a first region and a plurality of second cooling gas holes formed in a second region; and a substrate having a first flow path pattern connected to the plurality of first cooling gas holes, a second flow path pattern connected to the plurality of second cooling gas holes, and an inlet movement pattern for changing the inlet position of cooling gas injected into the first flow path pattern. The first region is an outer region of the electrostatic chuck plate, and the second region is an inner region of the electrostatic chuck plate.

[0016] More preferably, the substrate comprises: a first metal layer having an inlet movement pattern formed thereon; a second metal layer having a first flow path pattern formed thereon; and a third metal layer having a second flow path pattern formed thereon. Furthermore, the inlet movement pattern is formed such that it extends in a straight line from a location in the outer region of the first metal layer to a location in the inner region.

[0017] More preferably, the first flow path pattern causes the cooling gas flowing in from the inner region of the second metal layer to move horizontally to the outer region of the corresponding metal layer. Furthermore, the first flow path pattern is formed in a radial shape extending from the cooling gas holes disposed in the inner region of the second metal layer to the outer region of the corresponding metal layer.

[0018] More preferably, the substrate further comprises a fourth metal layer formed on top of the third metal layer, having a plurality of insulating members disposed in the adjacent region of the cooling gas holes formed on the electrostatic chuck plate. Furthermore, each insulating member is formed to surround at least a portion of the cooling gas holes formed on the fourth metal layer. Additionally, each insulating member is formed of aluminum oxide (Al2O3), the same material as the electrostatic chuck plate. Furthermore, each insulating member is formed of one of the following materials: polyetheretherketone (PEEK), polyamide-imide (PAI), and polybenzimidazole (PBI).

[0019] More preferably, the electrostatic chuck plate is characterized by being formed by sequentially stacking an insulating layer, an electrode layer, and a dielectric layer. Furthermore, the number of first cooling gas holes formed in the electrostatic chuck plate is 20 or less.

[0020] In addition, according to another aspect of the present invention, an electrostatic chuck is provided, characterized in that it comprises: a substrate; and an electrostatic chuck plate, the electrostatic chuck plate comprising an insulating layer on the substrate, an electrode layer on the insulating layer, and a dielectric layer on the electrode layer; and the dielectric layer having a plurality of first cooling gas holes formed in a first region and a plurality of second cooling gas holes formed in a second region, the insulating layer having a first flow path pattern connected to the plurality of first cooling gas holes, a second flow path pattern connected to the plurality of second cooling gas holes, and an inlet movement pattern for changing the inlet position of cooling gas injected into the first flow path pattern.

[0021] According to at least one embodiment of the present invention, a new cooling flow pattern is provided to address the asymmetric configuration structure of the first cooling gas holes formed on the substrate, thereby having the advantage that the density of the cooling gas released to the substrate can be uniformly represented by a plurality of second cooling gas holes.

[0022] In addition, according to at least one embodiment of the present invention, multiple insulating members are arranged around the multiple cooling gas holes formed in the electrostatic chuck plate, which has the advantage of effectively preventing plasma discharge caused by the process gas in the plasma state encountering the metal layer.

[0023] However, the effects that the electrostatic chuck of the present invention can achieve are not limited to those mentioned above. Other effects not mentioned are clearly understood by those skilled in the art from the following description. Attached Figure Description

[0024] Figure 1 This is a diagram showing the cooling structure of electrostatic chucks from previous technologies;

[0025] Figure 2a This is a diagram showing the upper shape of an electrostatic chuck according to an embodiment of the present invention;

[0026] Figure 2b Is it displayed along Figure 2a A diagram showing the cross-sectional shape of the electrostatic chuck cut off by line B-B'.

[0027] Figure 2c Yes Display Figure 2b A diagram showing the cross-sectional shape of the electrostatic chuck plate;

[0028] Figure 2d It is a magnified display. Figure 2b The diagram shown is part A.

[0029] Figures 3 to 8 It is a diagram showing the cooling structure formed by multiple metal layers constituting the substrate;

[0030] Figure 9 This is a graph showing the results of an experiment conducted according to an embodiment of the present invention to determine the He flow distribution of each hole based on the number of external cooling gas holes formed in the edge region of the electrostatic chuck plate.

[0031] Figure Labels

[0032] 100: Electrostatic chuck; 200: Substrate

[0033] 210: First metal layer; 220: Second metal layer

[0034] 230: Third metal layer; 240: Fourth metal layer

[0035] 300: Electrostatic chuck plate; 310: Insulation layer

[0036] 320: Electrode layer; 330: Dielectric layer Detailed Implementation

[0037] The embodiments disclosed herein will now be described in detail with reference to the accompanying drawings. Identical or similar constituent elements are given the same reference numerals, regardless of the drawing numbers, and repeated descriptions of these elements are omitted. In the following description of the embodiments of the present invention, for cases where layers (films), regions, patterns, or structures are described as being formed "on" or "under" the substrate, layers (films), regions, pads, or patterns, "on" or "under" includes cases where they are formed "directly" or "indirectly" from other layers. Furthermore, the references to the upper / lower / under each layer are explained with reference to the accompanying drawings. In the drawings, the thickness or size of each layer is exaggerated or omitted, or is shown schematically, for ease of explanation and clarity. Additionally, the sizes of the constituent elements do not fully reflect their actual sizes.

[0038] In describing the embodiments disclosed in this specification, detailed descriptions of relevant prior art are omitted when it is determined that such detailed descriptions may obscure the gist of the embodiments disclosed in this specification. Furthermore, the accompanying drawings are only used to facilitate a clearer understanding of the embodiments disclosed in this specification. The technical concepts disclosed in this specification are not limited by the drawings and should be understood to include all modifications, equivalents, and substitutions within the scope of the inventive concept and technology.

[0039] This invention proposes an electrostatic chuck for improving plasma discharge phenomena. Furthermore, this invention proposes an electrostatic chuck with uniform density of cooling gas discharged to the substrate. Additionally, this invention proposes an electrostatic chuck with a novel cooling flow path pattern. Furthermore, this invention proposes an electrostatic chuck with an optimal number of cooling gas holes relative to the cross-sectional area of ​​the cooling flow path. Finally, this invention proposes an electrostatic chuck with an insulating structure at the periphery of the plurality of cooling gas holes formed in the electrostatic chuck plate.

[0040] The various embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] Figure 2a This is a diagram showing the upper shape of an electrostatic chuck according to an embodiment of the present invention. Figure 2b Is it displayed along Figure 2a The diagram shows the cross-sectional shape of the electrostatic chuck cut off by line B-B'. Figure 2c Yes Display Figure 2b The diagram shows the cross-sectional shape of the electrostatic chuck plate. Figure 2d It is a magnified display. Figure 2b The diagram shown is part A.

[0042] If reference Figures 2a to 2d An embodiment of the electrostatic chuck 100 of the present invention includes a substrate 200 and an electrostatic chuck plate 300 disposed on the upper part of the substrate 200. On the other hand, although not shown in the figure, an adhesive layer (not shown in the figure) for bonding the respective substrate 200 and electrostatic chuck plate 300 may be formed between the substrate 200 and the electrostatic chuck plate 300.

[0043] The electrostatic chuck 100 may have a cooling structure for uniformly cooling the substrate inside the chamber using an external cooling gas. To embody this cooling structure, a plurality of first cooling gas holes 250 and a cooling flow pattern 260 may be formed on the substrate 200, and a plurality of second cooling gas holes 340 may be formed on the electrostatic chuck plate 300. Helium (He) is primarily used as the cooling gas, but it is not necessarily limited to this.

[0044] The substrate 200 can be formed as a multi-layer structure consisting of multiple metal layers. As an example, the substrate 200 can be formed by sequentially stacking a first metal layer 210, a second metal layer 220, a third metal layer 230, and a fourth metal layer 240. In this case, the individual metal layers 210 to 240 can be joined together by a brazing process, a welding process, or a bonding process.

[0045] At least one of the first to fourth metal layers 210-240 may have a cooling flow path pattern 260 for diffusing cooling gas in a horizontal direction. The cooling flow path pattern 260 may include an external flow path pattern for diffusing cooling gas to an external region of the substrate 200, an internal flow path pattern for diffusing cooling gas to an internal region of the substrate 200, and an inlet movement pattern for changing the position of a first cooling gas orifice connected to the external flow path pattern.

[0046] At least one of the first to fourth metal layers 210-240 may have a plurality of first cooling gas holes 250 for allowing cooling gas to pass through in a vertical direction. In this case, the plurality of first cooling gas holes 250 may be formed in a manner connected to a cooling flow path pattern formed within the substrate 200. Specifically, the plurality of first cooling gas holes 250 may include first external cooling gas holes connected to an external flow path pattern within the substrate 200, and first internal cooling gas holes connected to an internal flow path pattern within the substrate 200. A more detailed description of this will be provided later. Figures 3 to 8 Narrative.

[0047] The first to third metal layers 210-230 can be formed to have the same thickness and size. On the other hand, the fourth metal layer 240, located at the top of the substrate 200, can be formed to have a greater thickness than the other metal layers 210-230. In addition, the fourth metal layer 240 can be formed in such a way that its edge region has a predetermined staggered structure.

[0048] The electrostatic chuck plate 300 is a multi-layer structure that performs the function of an electrostatic chuck, including an insulating layer 310, an electrode layer 320 on the insulating layer 310, and a dielectric layer 330 on the electrode layer 320.

[0049] The insulating layer 310 may be made of ceramic material. As one embodiment, the insulating layer 310 may be formed of aluminum oxide (Al2O3). On the other hand, as another embodiment, in addition to aluminum oxide (Al2O3), the insulating layer 310 may also include at least one of aluminum nitride (AlN), silicon carbide (SiC), and silicon nitride (Si3N4).

[0050] The insulating layer 310 can be formed by performing a hot melt spraying process on the substrate 200. The insulating layer 310 thus formed performs the function of insulating the substrate 200 from the electrode layer 320.

[0051] The electrode layer 320 can be made of a conductive metal. As an example, the electrode layer 320 can be formed of at least one of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), and titanium (Ti), and more preferably, it can be formed of tungsten (W).

[0052] The electrode layer 320 can be formed using a hot melt spraying process or a screen printing process. The electrode layer 320 has a thickness of approximately 30 μm to 50 μm. For example, if the thickness of the electrode layer 320 is less than 30 μm, the impedance value increases due to porosity and other defects within the electrode layer. As the impedance value increases, the electrostatic adsorption force decreases, which is therefore not recommended. Furthermore, if the thickness of the electrode layer 320 exceeds 50 μm, overcurrent may occur, potentially leading to arcing, which is also not recommended. Therefore, it is preferable that the thickness of the electrode layer 320 is in the range of approximately 30 μm to 50 μm.

[0053] The electrode layer 320 can be formed into various shapes, such as a plate-like structure, a spiral structure, or a concentric circle structure. The electrode layer 320 thus formed performs the function of generating the electrostatic force required to hold the substrate (not shown in the figure) placed on top of the dielectric layer 330.

[0054] The dielectric layer 330 can be made of ceramic material. As one embodiment, the dielectric layer 330 can be formed of aluminum oxide (Al2O3), the same material as the insulating layer 310 described above. Alternatively, as another embodiment, in addition to aluminum oxide (Al2O3), the dielectric layer 330 can be supplemented with at least one of silicon oxide (SiO2), palladium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), and zirconium oxide (ZrO2).

[0055] The dielectric layer 330 can be formed by performing a hot melt spraying process on the insulating layer 310 and the electrode layer 320. The dielectric layer 330 thus formed performs the dielectric function so as to generate electrostatic force by means of the electrode layer 320.

[0056] The electrostatic chuck plate 300, thus formed with a multi-layer structure, can have a plurality of second cooling gas holes 340 for discharging cooling gas for cooling the substrate. In this case, the plurality of second cooling gas holes 340 can be formed in connection with a cooling flow path pattern formed inside the substrate 200. Specifically, the plurality of second cooling gas holes 340 may include second external cooling gas holes 341 connected to an external flow path pattern within the substrate 200, and second internal cooling gas holes 343 connected to an internal flow path pattern within the substrate 200.

[0057] The plurality of second cooling gas holes 340 formed in the electrostatic chuck plate 300 can be arranged in a predetermined pattern. Furthermore, the plurality of second cooling gas holes 340 can be formed in a predetermined number and size. For example, in this embodiment, an example is given where the electrostatic chuck plate 300 has 8 external helium gas holes 341 and 13 internal helium gas holes 343, but this is not a limitation.

[0058] On the other hand, when the surrounding environment of the plurality of second cooling gas holes 340 formed in the electrostatic chuck plate 300 meets the mean free path based on a specific pressure, plasma discharge is likely to occur. To prevent this plasma discharge phenomenon, a predetermined insulating material needs to be reinforced around the second cooling gas holes 340. Therefore, the fourth metal layer 240 adjacent to the electrostatic chuck plate 300 may include a plurality of insulating members 270, which can effectively remove the plasma discharge phenomenon caused by the plasma-state process gas injected through the second cooling gas holes 340 formed in the corresponding plate 300 when it encounters the metal layer.

[0059] For example, such as Figure 2d As shown, each insulating member 270 may be disposed on the lower part of the electrostatic chuck plate 300 adjacent to the region of the second cooling gas hole 340 formed on the electrostatic chuck plate 300. Additionally, each insulating member 270 may be formed to surround at least a portion of the first cooling gas hole 250 formed in the fourth metal layer 240 of the substrate 200. As an example, the insulating member 270 may be formed in a cylindrical shape, but is not necessarily limited to this.

[0060] Each insulating member 270 can be formed to have a height that is the same as or less than that of the fourth metal layer 240. Furthermore, each insulating member 270 can be formed of a predetermined insulating material. As one embodiment, the insulating member 270 can be formed of aluminum oxide (Al2O3), which is the same material as the insulating layer 310 and the dielectric layer 330. Alternatively, the insulating member 270 can also be formed of polyetheretherketone (PEEK), polyamide-imide (PAI), or polybenzimidazole (PBI), etc.

[0061] On the other hand, in this embodiment, the example is that the substrate is composed of four metal layers, but it is not necessarily limited to this. The substrate can be formed with more or fewer metal layers, which is self-evident to those skilled in the art.

[0062] As described above, an embodiment of the electrostatic chuck of the present invention provides a novel cooling flow pattern for addressing the asymmetric configuration of the first external cooling gas holes formed on the substrate, thereby uniformly reflecting the density of the cooling gas released to the substrate through the plurality of second cooling gas holes formed on the electrostatic chuck plate. Furthermore, the electrostatic chuck has a plurality of insulating members disposed around the periphery of the second cooling gas holes formed on the electrostatic chuck plate, thereby effectively preventing plasma discharge phenomena caused by the plasma-state process gas encountering the metal layer.

[0063] Figures 3 to 8 It is a diagram showing the cooling structure formed by multiple metal layers constituting the substrate.

[0064] first, Figure 3 This is a diagram showing the cooling structure formed in the first metal layer as viewed from above. (Example) Figure 3 As shown, the first metal layer (or inlet moving layer) 210 may include a first external cooling gas hole 211, a plurality of first internal cooling gas holes 213 and an inlet moving pattern 215.

[0065] The first external cooling gas hole 211 can be disposed in the external region (i.e., the edge region) of the first metal layer 210. In addition, the first external cooling gas hole 211 has a predetermined shape and can be formed through the vertical direction. Therefore, external cooling gas passes through the first external cooling gas hole 211 and moves to the inlet movement pattern 215 of the first metal layer 210.

[0066] Multiple first internal cooling gas holes 213 can be arranged at predetermined intervals (i.e., equal intervals) in the internal region (i.e., central region) of the first metal layer 210. Similarly, the multiple first internal cooling gas holes 213 can have a predetermined shape and be formed through each other in a vertical direction. Therefore, external cooling gas moves through the multiple first internal cooling gas holes 213 toward the second metal layer 220.

[0067] The inlet movement pattern 215, serving as a flow path for cooling gas flowing in from one location on the first metal layer 210 to diffuse to other locations (or move horizontally), can be formed to extend from the first external cooling gas hole 211 disposed in the outer region of the first metal layer 210 to a location in the inner region of the first metal layer 210. Therefore, the cooling gas injected into the outer region of the first metal layer 210 moves along the inlet movement pattern 215 to a location in the inner region of the first metal layer 210.

[0068] The inlet movement pattern 215 can have a predetermined width and be formed in a straight line. Furthermore, the inlet movement pattern 215 can be formed by etching the top surface of the first metal layer 210 to a predetermined depth. This inlet movement pattern 215 functions to move the position of the first external cooling gas hole, which connects to the external flow path pattern of the substrate, from the external region to the internal region. Therefore, the inlet movement pattern 215 can solve the problem of uneven cooling gas density caused by the asymmetrical configuration of the first external cooling gas holes formed in the electrostatic chuck.

[0069] Figure 4 and Figure 5 This is a diagram showing the cooling structure formed in the second metal layer as viewed from above. (Example) Figure 4 and Figure 5 As shown, the second metal layer (or external flow path pattern layer) 220 may include a first external cooling gas hole 221, a plurality of first internal cooling gas holes 223 and an external flow path pattern 225.

[0070] The first external cooling gas hole 221 can be disposed at a location within the internal region of the second metal layer 220. In this case, the first external cooling gas hole 221 can be connected to the inlet movement pattern 215 of the first metal layer 210. Furthermore, the first external cooling gas hole 221 can have a predetermined shape and be formed vertically. Therefore, cooling gas injected from the first metal layer 210 passes through the first external cooling gas hole 221 and moves to the external flow path pattern 225 of the second metal layer 220.

[0071] Multiple first internal cooling gas holes 223 can be arranged at predetermined intervals in the internal region of the second metal layer 220. The multiple first internal cooling gas holes 223 can correspond to the positions of multiple first internal cooling gas holes 213 formed in the first metal layer 210. Similarly, the multiple first internal cooling gas holes 223 can have a predetermined shape and be formed through a vertical direction. Therefore, cooling gas injected from the first metal layer 210 passes through the multiple first internal cooling gas holes 223 and moves to the internal flow path pattern of the third metal layer 230.

[0072] The external flow path pattern 225 serves as a flow path for cooling gas flowing in from a location within the interior region of the second metal layer 220 to diffuse (or move horizontally) to the exterior region of the corresponding metal layer 220. It extends radially from the cooling gas holes 221 disposed within the interior region of the second metal layer 220 to the exterior region of the corresponding metal layer 220. Therefore, the cooling gas injected through the first external cooling gas holes 221 formed in the second metal layer 220 moves along the external flow path pattern 225 to the exterior region of the corresponding metal layer 220.

[0073] As an example, such as Figure 4 As shown, the external flow path pattern 225 may include first to third straight flow paths that extend radially from a location in the interior region of the second metal layer 220, and circular flow paths that extend in a circular manner to meet the terminal locations of the first to third straight flow paths.

[0074] On the other hand, as another embodiment, such as Figure 5 As shown, the external flow path pattern 225 may include first to third straight flow paths extending radially from a location in the inner region of the second metal layer 220, a first circular flow path extending in a circular manner to meet the ends of the first to third straight flow paths, and a second circular flow path formed through a portion of the first to third straight flow paths and smaller than the first circular flow path. Furthermore, external flow path patterns with various shapes can also be formed, as is self-evident to those skilled in the art.

[0075] The external flow path pattern 225 can be formed by etching the upper surface of the second metal layer 220 to a predetermined depth. This external flow path pattern 225 performs the function of uniformly distributing the cooling gas injected through the first external cooling gas hole 221 formed in the second metal layer 220 to the surrounding area.

[0076] Figure 6 and Figure 7 This is a diagram showing the cooling structure formed in the third metal layer as viewed from above. (Example) Figure 6 and Figure 7 As shown, the third metal layer (or internal flow path pattern layer) 230 may include a plurality of first external cooling gas holes 231, a plurality of first internal cooling gas holes 233, and an internal flow path pattern 235.

[0077] Multiple first external cooling gas holes 231 can be arranged at predetermined intervals in the outer region of the third metal layer 230. These first external cooling gas holes 231 can then be connected to the external flow path pattern 225 formed in the second metal layer 220. Furthermore, these first external cooling gas holes 231 can be connected to multiple first external cooling gas holes 241 formed in the fourth metal layer 240. Therefore, cooling gas injected from the second metal layer 220 passes through the multiple first external cooling gas holes 231 and moves to the fourth metal layer 240.

[0078] Multiple first internal cooling gas holes 233 may be arranged at predetermined intervals (i.e., equal intervals) in the internal region of the third metal layer 230. The multiple first internal cooling gas holes 233 may be formed corresponding to the positions of multiple first internal cooling gas holes 223 formed in the second metal layer 220. Therefore, cooling gas injected from the second metal layer 220 passes through the multiple first internal cooling gas holes 233 and moves to the internal flow path pattern 235 of the third metal layer 230.

[0079] The internal flow path pattern 235 serves as a flow path for the cooling gas flowing into the internal region above the third metal layer 230 to diffuse (or move horizontally) to the peripheral region, and can be formed in a predetermined shape. Therefore, the cooling gas injected through the plurality of first internal cooling gas holes 233 formed in the third metal layer 230 moves along the internal flow path pattern 235 to the peripheral region of the corresponding metal layer 230.

[0080] As an example, such as Figure 6 As shown, the internal flow pattern 235 may include a first straight flow path passing through the center of the third metal layer 230 and a portion of the first internal cooling gas hole, a second straight flow path passing through the center of the third metal layer 230 and the remaining portion of the first internal cooling gas hole, a first circular flow path extending in a circular manner to meet the ends of the first and second straight flow paths, and a second circular flow path that is smaller than the first circular flow path but passes through a portion of the first and second straight flow paths. The first and second straight flow paths may be formed at right angles to each other.

[0081] On the other hand, as another embodiment, such as Figure 7 As shown, the internal flow pattern 235 may include a first circular flow path with a first radius based on the upper center of the third metal layer 230, a second circular flow path with a second radius smaller than the first radius, a first to fourth straight flow path connecting the first and second circular flow paths with a straight line, and a first to fourth curved flow path formed by extending a predetermined distance along the circumference from the center point of the first to fourth straight flow paths. Furthermore, internal flow patterns with various shapes can also be formed, as is self-evident to those skilled in the art.

[0082] The internal flow pattern 235 can be formed by etching the upper surface of the third metal layer 230 to a predetermined depth. This internal flow pattern 235 performs the function of uniformly distributing the cooling gas injected through the first internal cooling gas hole 233 formed in the third metal layer 230 to the surrounding area.

[0083] Figure 8 This is a diagram showing the cooling structure formed in the fourth metal layer as viewed from above. (Example) Figure 8As shown, the fourth metal layer 240 may include a plurality of first external cooling gas holes 241 and a plurality of first internal cooling gas holes 243.

[0084] Multiple first external cooling gas holes 241 can be disposed in the outer region of the fourth metal layer 240. In this case, the multiple first external cooling gas holes 241 can be connected to multiple first external cooling gas holes 231 formed in the third metal layer 230. Additionally, the multiple first external cooling gas holes 241 can be connected to multiple second external cooling gas holes 341 formed in the electrostatic chuck plate 300. Therefore, cooling gas injected from the third metal layer 230 passes through the multiple first external cooling gas holes 241 and moves to the electrostatic chuck plate 300. The electrostatic chuck plate 300 releases the cooling gas injected from the fourth metal layer 240 to the outside through the multiple second external cooling gas holes 341.

[0085] Multiple first internal cooling gas holes 243 can be arranged at predetermined intervals in the internal region of the fourth metal layer 240. These first internal cooling gas holes 243 can then be connected to the internal flow path pattern 235 formed in the third metal layer 230. Furthermore, these first internal cooling gas holes 243 can be connected to multiple second internal cooling gas holes 343 formed in the electrostatic chuck plate 300. Therefore, cooling gas injected from the third metal layer 230 passes through the multiple first internal cooling gas holes 243 and moves to the electrostatic chuck plate 300. The electrostatic chuck plate 300 releases the cooling gas injected from the fourth metal layer 240 to the outside through the multiple second internal cooling gas holes 343. On the other hand, in this embodiment, the example given is a cooling structure with an inlet movement pattern, an external flow path pattern, and an internal flow path pattern formed inside the substrate, but it is not necessarily limited to this. Therefore, the cooling structure with an inlet movement pattern, an external flow path pattern, and an internal flow path pattern can be formed inside the electrostatic chuck plate, i.e., in the insulating layer, which is self-evident to those skilled in the art. At this point, only a number of cooling gas holes can be formed on the substrate, and multiple insulating components can be omitted from the electrostatic chuck plate.

[0086] On the other hand, despite the inlet movement pattern 215 formed on the substrate 200, the density (content) distribution of the cooling gas released through the second external cooling gas hole 341 formed on the electrostatic chuck plate 300 is relatively less uniform compared to the density distribution of the cooling gas released through the plurality of second internal cooling gas holes 343 formed on the corresponding plate 300. This is because there is only one first external cooling gas hole formed on the bottom surface of the substrate 200, while there are multiple first internal cooling gas holes formed on the bottom surface of the substrate 200. Therefore, an optimal number of external cooling gas holes is needed compared to the cross-sectional area of ​​the cooling flow path to make the density of the cooling gas released from the outer region of the electrostatic chuck plate 300 more uniform.

[0087] Figure 9 This is a graph showing the results of an experiment conducted according to an embodiment of the present invention to determine the He flow distribution of each hole based on the number of external cooling gas holes formed in the edge region of the electrostatic chuck plate.

[0088] Right now, Figure 9 (a) is a graph measuring the He flow distribution in each of the 10 external cooling gas holes in an electrostatic chuck. Figure 9 (b) is a second experimental example, which is a graph measuring the He flow distribution of each external cooling gas hole in an electrostatic chuck with 20 external cooling gas holes. Figure 9 (c) is the third experimental example, a graph showing the He flow rate distribution at each of the 30 external cooling gas holes in an electrostatic chuck. Finally, Figure 9 (d) is the fourth experimental example, which is a graph measuring the He flow distribution of each external cooling gas hole in an electrostatic chuck with 40 external cooling gas holes.

[0089] If Figure 9 Based on the flow rates of each cooling gas orifice measured in the first to fourth experimental examples, various parameter values ​​(such as maximum value, minimum value, maximum value - minimum value, total value, average value, standard deviation value, minimum value / maximum value, etc.) were calculated and organized, as shown in the table below.

[0090] Table 1

[0091]

[0092]

[0093] In Table 1 above, the MAX value is the maximum value of the orifice flow rate measured in each experimental example, the MIN value is the minimum value of the orifice flow rate measured in each experimental example, the MAX-MIN value is the difference between the maximum and minimum values ​​of the orifice flow rate measured in each experimental example, the SUM value is the sum of all the orifice flow rate values ​​measured in each experimental example, the AVR value is the average value of all the orifice flow rate values ​​measured in each experimental example, and the MIN / MAX value is the ratio of the minimum value to the maximum value of the orifice flow rate measured in each experimental example.

[0094] Among these parameters, the ones related to the uniform distribution of helium density are the MAX-MIN value, the standard deviation value, and the MIN / MAX value. Analysis of the MAX-MIN values ​​in each experimental example confirms that when the MAX-MIN value is below 15, the helium density is relatively uniform. Furthermore, analysis of the standard deviation values ​​in each experimental example confirms that when the standard deviation value is below 5, the helium density is relatively uniform. Additionally, analysis of the MIN / MAX values ​​in each experimental example confirms that when the MIN / MAX value is above 30%, the helium density is relatively uniform.

[0095] Therefore, it can be confirmed that when the number of external cooling gas holes formed in the edge region of the electrostatic chuck plate is 20 or less, more preferably when the number of external cooling gas holes is 10 or less, the density of the helium gas released from the corresponding cooling gas holes is relatively uniform.

[0096] On the other hand, while specific embodiments of the present invention have been described above, various modifications are naturally possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined according to the following claims and their equivalents.

Claims

1. An electrostatic chuck, comprising: An electrostatic chuck plate, the electrostatic chuck plate including a plurality of first cooling gas holes formed in a first region and a plurality of second cooling gas holes formed in a second region; and The substrate includes a first flow path pattern connected to the plurality of first cooling gas holes, a second flow path pattern connected to the plurality of second cooling gas holes, an inlet moving pattern for changing the inlet position of cooling gas injected into the first flow path pattern, and a plurality of third cooling gas holes for injecting cooling gas by connecting to the inlet moving pattern and the second flow path pattern. A portion of the cooling gas injected from the plurality of third cooling gas holes flows into the first flow path pattern via the inlet movement pattern and then into the plurality of first cooling gas holes; another portion of the cooling air flows into the second flow path pattern and then into the plurality of second cooling gas holes. The first region is the outer region on the electrostatic chuck plate. The second region is the inner region on the electrostatic chuck plate. The substrate includes: A first metal layer having the aforementioned inlet movement pattern formed thereon; A second metal layer having the first flow path pattern formed thereon; and A third metal layer is formed with the second flow path pattern.

2. The electrostatic chuck according to claim 1, characterized in that, The inlet movement pattern is formed by extending a straight line from a location in the outer region of the first metal layer to a location in the inner region.

3. The electrostatic chuck according to claim 1, characterized in that, The first flow path pattern causes the cooling gas flowing in from the inner region of the second metal layer to move horizontally to the outer region of the corresponding metal layer.

4. The electrostatic chuck according to claim 1, characterized in that, The first flow path pattern is formed to extend radially from the cooling gas holes disposed in the inner region of the second metal layer to the outer region of the corresponding metal layer.

5. The electrostatic chuck according to claim 1, characterized in that, The substrate further includes a fourth metal layer. The fourth metal layer is formed on top of the third metal layer and has a plurality of insulating members disposed in the adjacent region of the cooling gas holes formed on the electrostatic chuck plate.

6. The electrostatic chuck according to claim 5, characterized in that, Each insulating component is formed to surround at least a portion of the cooling gas pores formed in the fourth metal layer.

7. The electrostatic chuck according to claim 5, characterized in that, Each insulating component is formed of aluminum oxide, the same material as the electrostatic chuck plate.

8. The electrostatic chuck according to claim 5, characterized in that, Each insulating component is made of one of the following materials: polyetheretherketone, polyamide-imide, and polybenzimidazole.

9. The electrostatic chuck according to claim 1, characterized in that, The number of first cooling gas holes formed on the electrostatic chuck plate is 20 or less.

10. The electrostatic chuck according to claim 1, characterized in that, The electrostatic chuck plate is formed by stacking an insulating layer, an electrode layer, and a dielectric layer in sequence.

11. An electrostatic chuck, characterized in that, include: Substrate; and An electrostatic chuck plate, the electrostatic chuck plate comprising an insulating layer on the substrate, an electrode layer on the insulating layer, and a dielectric layer on the electrode layer; and The dielectric layer has a plurality of first cooling gas holes formed in a first region and a plurality of second cooling gas holes formed in a second region. The insulating layer includes a first flow path pattern connected to the plurality of first cooling gas holes, a second flow path pattern connected to the plurality of second cooling gas holes, an inlet moving pattern for changing the inlet position of the cooling gas injected into the first flow path pattern, and a plurality of third cooling gas holes for injecting cooling gas by connecting to the inlet moving pattern and the second flow path pattern. A portion of the cooling gas injected from the plurality of third cooling gas holes flows into the first flow path pattern via the inlet movement pattern and then into the plurality of first cooling gas holes; another portion of the cooling air flows into the second flow path pattern and then into the plurality of second cooling gas holes. The first region is the outer region on the electrostatic chuck plate. The second region is the inner region on the electrostatic chuck plate. The substrate includes: A first metal layer having the aforementioned inlet movement pattern formed thereon; A second metal layer having the first flow path pattern formed thereon; and A third metal layer is formed with the second flow path pattern.

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