Electrostatic Chuck With Horizontal Flow Path Channel And Porous Member Used Therein

Abstract

The present invention relates to a cooling gas flow path structure of an electrostatic chuck. The present invention provides an electrostatic chuck comprising a cooling gas flow path for cooling a substrate on a dielectric plate with a cooling gas passing through a base and a dielectric plate, wherein the cooling gas flow path comprises: a gas inlet path provided in the base for supplying cooling gas; a through hole provided on the surface of the dielectric plate and communicating with the gas inlet path; a porous member on the cooling gas flow path between the gas inlet path and the through hole; and a plurality of cooling gas flow path channels provided between the porous member and the through hole, wherein the plurality of cooling gas flow path channels include an inner channel connected to the through hole and an outer channel surrounding the outer edge of the inner channel, and the inner channel and the outer channel are in communication at least one side.

Description

Technology Field

[0001] The present invention relates to an electrostatic chuck, and more specifically, to a cooling gas flow path structure of an electrostatic chuck. Background Technology

[0002] Semiconductor devices or display devices are manufactured by stacking and patterning multiple thin film layers, including dielectric layers and metal layers, on a glass substrate, a flexible substrate, or a semiconductor wafer substrate through semiconductor processes such as chemical vapor deposition (CVD), physical vapor deposition (PVD), ion implantation, and etching. A chamber device for performing these semiconductor processes is equipped with an electrostatic chuck (ESC) that supports various substrates, such as glass substrates, flexible substrates, and semiconductor wafer substrates, and specifically fixes the said substrate using electrostatic force.

[0003] In order to uniformly cool a substrate held on a dielectric plate using an external cooling gas, such an electrostatic chuck has a base and a dielectric plate bonded thereto that have a predetermined cooling structure. Generally, the cooling structure is provided such that a cooling gas channel provided in the base communicates with a gas hole provided in the dielectric plate.

[0004] For example, conventional electrostatic chucks are equipped with a structure that includes a porous structure between the gas channel of the base and the gas hole of the dielectric plate, or within the gas hole of the dielectric plate, in order to increase the distribution of process gas supply and prevent arcing near the plate surface. In a gas channel structure containing such a porous structure, it is required to suppress discharge within the gas channel while simultaneously facilitating the smooth flow of the gas. Prior art literature

[0005] (1) Japanese Patent Publication No. 2010-123712 The problem to be solved

[0006] The present invention aims to provide an electrostatic chuck having a cooling gas flow path that facilitates the flow of cooling gas.

[0007] In addition, the present invention aims to provide an electrostatic chuck that suppresses discharge within a cooling gas flow path.

[0008] In addition, the present invention aims to provide an electrostatic chuck with a cooling gas flow path structure that enables even distribution of cooling gas.

[0009] In addition, the present invention aims to provide a porous member suitable for use in the aforementioned electrostatic chuck. means of solving the problem

[0010] To achieve the above technical objective, the present invention provides an electrostatic chuck having a cooling gas channel for cooling a substrate on a dielectric plate through a base and a dielectric plate with a cooling gas, wherein the cooling gas channel comprises: a gas inlet channel provided on the base for supplying cooling gas; a through hole provided on the surface of the dielectric plate and communicating with the gas inlet channel; a porous member on the cooling gas channel between the gas inlet channel and the through hole; and a plurality of cooling gas channel channels provided between the porous member and the through hole, wherein the plurality of cooling gas channel channels include an inner channel connected to the through hole and an outer channel surrounding the outer edge of the inner channel, and the inner channel and the outer channel are in communication at least one side.

[0011] In the present invention, the outer channel may be extended in a horizontal direction.

[0012] In the present invention, the inner channel and the outer channel may be partitioned by a plurality of protrusions protruding from the inner wall of the cooling gas flow path. In this case, the plurality of protrusions may be arranged with rotational symmetry with respect to the center of the cooling gas flow path.

[0013] In contrast, in the present invention, the inner channel and the outer channel may be partitioned by a protrusion protruding from the porous member. In this case, the plurality of protrusions may be arranged with rotational symmetry with respect to the center of the cooling gas flow path, and the inner channel and the outer channel may be connected in a horizontal direction.

[0014] In the present invention, a horizontal connecting channel may be provided to communicate the inner channel and the outer channel in a horizontal direction.

[0015] In the present invention, the height of the outer channel may be the same as the height of the horizontal connecting channel. Alternatively, the height of the outer channel may be higher or lower than the height of the horizontal connecting channel.

[0016] In the present invention, the width of the outer channel may be 0.2 to 1 mm.

[0017] To achieve the above other technical objectives, the present invention provides a porous member having a predetermined volume, a first surface and a second surface perpendicular to the flow of cooling gas, which is mounted in a cooling gas channel of an electrostatic chuck, wherein the porous member has a plurality of protrusions on the first surface or the second surface, and when mounted in the cooling gas channel, the plurality of protrusions face the cooling gas channel to partition an inner channel and an outer channel of the porous member, and the outer channel surrounds the outer periphery of the inner channel.

[0018] In the present invention, the outer channel may be extended in a horizontal direction.

[0019] In the present invention, the plurality of protrusions may be arranged with rotational symmetry with respect to the center of the cooling gas flow path.

[0020] In the present invention, the height of the protrusion may be 0.1 to 1 mm. Effects of the invention

[0021] According to the present invention, it is possible to provide an electrostatic chuck having a cooling gas channel that facilitates the flow of cooling gas.

[0022] In addition, according to the present invention, it is possible to provide an electrostatic chuck that suppresses discharge within a cooling gas flow path.

[0023] In addition, according to the present invention, it is possible to provide an electrostatic chuck having a cooling gas flow path structure that enables even distribution of cooling gas. Brief explanation of the drawing

[0024] FIG. 1 is a schematic cross-sectional view of an electrostatic chuck according to one embodiment of the present invention. Figure 2 is an enlarged view of part A of Figure 1. Figure 3 is a diagram illustrating a Euro formed with channels described in relation to Figure 2. FIG. 4 is a drawing illustrating horizontal channels according to another embodiment of the present invention. FIG. 5 is a schematic diagram illustrating another example of forming a cooling gas flow path structure of an electrostatic chuck according to the present invention. FIG. 6 is a schematic perspective view illustrating a porous member used in the Euro structure of FIG. 5. Specific details for implementing the invention

[0025] The present invention will be described in detail below with reference to the attached drawings. In this case, identical components in each drawing are denoted by the same reference numerals whenever possible. Furthermore, detailed descriptions of already known functions and / or configurations are omitted. The content disclosed below focuses on the parts necessary for understanding the operation according to various embodiments, and descriptions of elements that may obscure the gist of the explanation are omitted. Additionally, some components in the drawings may be exaggerated, omitted, or schematically depicted. The size of each component does not entirely reflect its actual size, and therefore, the contents described herein are not limited by the relative sizes or spacing of the components depicted in each drawing.

[0026] In describing the embodiments of the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such detailed descriptions may unnecessarily obscure the essence of the invention. Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are intended merely to describe the embodiments of the present invention and are by no means restrictive. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form. In this description, expressions such as "include" or "comprise" are intended to refer to certain characteristics, numbers, steps, actions, elements, parts thereof, or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts thereof, or combinations thereof other than those described.

[0027] Additionally, terms such as first, second, etc., may be used to describe various components, but said components are not limited by said terms, and said terms are used only for the purpose of distinguishing one component from another.

[0028] FIG. 1 is a schematic cross-sectional view of an electrostatic chuck (100) according to one embodiment of the present invention.

[0029] Referring to FIG. 1, an electrostatic chuck (100) according to one embodiment of the present invention includes a base (200) and a dielectric plate (110). The electrostatic chuck (100) is preferably of a circular type, but may be designed in other shapes such as an elliptical or square shape depending on the case.

[0030] The base (200) may be implemented using a metal material such as aluminum or an aluminum alloy. The base (200) may be implemented using a composite of the aforementioned metal and ceramic. Additionally, the base (200) may be formed as a multi-layer structure. These layers may be joined through a brazing process, a welding process, or a bonding process. The base (200) may be provided with a refrigerant flow path (220).

[0031] The dielectric plate (110) is bonded onto the base (200) and can be bonded onto the base (200) using a predetermined fixing means or an adhesive / bonding means. The base (200) and the dielectric plate (110) may be manufactured separately and then bonded, and in some cases, it is also possible to form a structure of the dielectric plate (110) directly on the upper surface of the base (200) using a ceramic sheet or the like.

[0032] As shown in FIG. 1, the dielectric plate (110) is made of a dielectric material and may contain one or more electrodes (310). A dielectric plate (110) of this structure can be implemented in various ways. An example is described in which the dielectric plate is implemented as a plurality of layers.

[0033] The above dielectric plate (110) can be implemented in a stacked structure such as an insulating layer, an electrode layer on the insulating layer, and a dielectric layer on the electrode layer.

[0034] At this time, the insulating layer may be made of a ceramic material. In one embodiment, the insulating layer may be made of a material selected from aluminum oxide (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (Si3N4), silicon oxide (SiO2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), zirconium oxide (ZrO2), Y2O3, YAG, YAM, YAP, etc. The insulating layer may be formed on the upper surface of the base (200) by performing a thermal spray coating or a ceramic sheet attachment process with the ceramic material as described above. The insulating layer formed in this way performs the function of insulating between the base and the electrode layer.

[0035] The electrode layer may be made of a conductive metal material. As an example, the electrode layer may be formed from at least one of silver (Ag), gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), and titanium (Ti), and more preferably, may be formed from tungsten (W). The electrode layer may be formed using a thermal spray coating process or a screen printing process. The electrode layer has a thickness of about 1.0 μm to 100 μm. For example, preferably, when forming the electrode layer by a screen printing process, a thickness of 1.0 to 30 μm may be applied, and when forming the electrode layer by a thermal spray coating process, a thickness of 30 to 100 μm may be applied. However, it is difficult to form a layer that is too thin, such as having a thickness of less than 1.0 μm, so it is not desirable. Furthermore, in this case, the resistance value increases due to porosity and other defects within the electrode layer, and as the resistance value increases, a phenomenon may occur in which the electrostatic adsorption force decreases, so it is not desirable. In addition, if the thickness of the electrode layer is too thick, such as exceeding 100 μm, an arcing phenomenon may occur, which is undesirable. Therefore, it is desirable to apply an appropriate value for the thickness of the electrode layer within the range of approximately 1.0 μm to 100 μm. The electrode layer formed in this way can generate electrostatic force by receiving a bias when loading a substrate (10) placed on top of the dielectric layer, thereby enabling chucking. When unloading the substrate (not shown), de-chucking is achieved by applying an opposite bias to the electrode layer to cause discharge. The electrode layer includes electrode patterns for such chucking and de-chucking, but is not limited thereto; in some cases, additional electrode patterns for a heater or high-frequency electrode patterns for plasma generation may also be included.

[0036] The dielectric layer may be made of a ceramic material. In one embodiment, the dielectric layer may be made of a material selected from aluminum oxide (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (Si3N4), silicon oxide (SiO2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), zirconium oxide (ZrO2), Y2O3, YAG, YAM, YAP, etc., which are the same material as the insulating layer described above. For example, the dielectric layer described above may be formed by a coating process such as thermal spray coating or aerosol coating. Alternatively, the dielectric layer may be formed by attaching it in the form of a sheet and then performing a sintering process.

[0037] The base (200) and the dielectric plate (110) have a cooling gas channel formed in the vertical direction of the base and the dielectric plate to guide a cooling gas, such as helium, to the surface of the dielectric plate. In the specification of the present invention, the vertical direction refers to the direction penetrating the base and the insulating plate, and the direction perpendicular to this direction is referred to as the horizontal direction. Furthermore, extending this meaning, the vertical channel refers to a channel extending in the vertical direction, and the horizontal channel refers to a channel extending in the horizontal direction. In addition, in the present invention, the cooling gas channel refers to the path through which the cooling gas passes until it is discharged to the substrate (10) after passing through the base and the plate. Therefore, the cooling gas introduction path (210) and the through hole (130) described later may be part of the cooling gas channel.

[0038] In the present invention, the cooling gas flow path may typically have a circular cross-sectional shape, but the present invention is not limited thereto. For example, it goes without saying that a flow path having a polygonal cross-sectional shape, such as a square, may be used.

[0039] Referring again to FIG. 1, the cooling gas is introduced through the cooling gas introduction channel (210) of the base (200), passes through the base and the dielectric plate, and is discharged through the dielectric plate surface penetration hole (130).

[0040] One or more porous members (140) may be provided in the middle of the cooling gas flow path, for example, in the flow path inside the dielectric plate, the flow path at the boundary between the dielectric plate and the base, or in the flow path inside the base. The porous members (140) may have a shape corresponding to the shape of the flow path. For example, the porous members (140) may be cylindrical members.

[0041] The porous member (140) is provided with microchannels that block contaminants such as particles but allow cooling gas to pass through. For example, the microchannels may be implemented by open channels of pores. Alternatively, the microchannels may be implemented by a plurality of microchannels parallel to the longitudinal direction of the porous member (140).

[0042] The above porous member (140) may be implemented by an insulating material such as ceramic. For example, as a ceramic material, a composition combining one or more of aluminum oxide (Al2O3), aluminum nitride (AlN), silicon carbide (SiC), silicon nitride (Si3N4), silicon oxide (SiO2), barium oxide (BaO), zinc oxide (ZnO), cobalt oxide (CoO), tin oxide (SnO2), and zirconium oxide (ZrO2) may be used.

[0043] Additionally, in the present invention, the outer surface of the porous member (140) may be in contact with a cooling gas flow path. At this time, the porous member (140) may be provided with a dense liner in the portion in contact with the cooling gas.

[0044] Figure 2 is an enlarged view of part A of Figure 1, and Figure 3 is a view of a flow path in which the channels described in relation to Figure 2 are formed.

[0045] As described, a porous member (140) is installed adjacent to the lower part of the through hole (130) in the cooling gas path to suppress plasma discharge.

[0046] Additionally, as described, cooling gas flow channels are provided between the porous member (140) and the through hole (130) in the present invention. The cooling gas flow channels include an inner channel and an outer horizontal channel outside the inner channel.

[0047] As described above, the inner channel and the outer horizontal channel are partitioned by a plurality of protrusions (120) that protrude downward from the cooling gas flow path wall near the through hole (130). Additionally, the height of the plurality of protrusions (120) may define the height (h1) of the inner channel and / or the height (h2) of the outer horizontal channel. In the present invention, the height of the channel refers to the distance between the bottom of the channel and the ceiling of the channel.

[0048] In the present invention, the height of the plurality of protrusions (120) is preferably 0.1 to 1 mm. If the height of the protrusions is 1 mm or more, the flow rate of the gas passing through the channel may be slowed down.

[0049] Preferably, the plurality of protrusions (120) are arranged to have rotational symmetry with respect to the center of the flow path. In FIG. 3, it can be seen that the protrusions have 90-degree rotational symmetry. The rotational symmetry of the protrusions can impart symmetry to the flow path and help maintain a more uniform cooling gas flow over the cross-section of the flow path. However, the present invention does not exclude an asymmetric arrangement of protrusions or an asymmetric arrangement of the flow path.

[0050] The protrusion in Fig. 3 has a fan shape on the cross-section of the Euro, but this is merely an example. It is obvious that it can have various planar shapes, such as circular or polygonal.

[0051] In the present invention, the inner channel is connected to the through hole (130), and the width of the inner channel is greater than the width (or diameter) of the through hole (130).

[0052] In addition, in the present invention, an outer horizontal channel (150B) is provided along the outer circumference of the inner channel. In the present invention, the width of the outer horizontal channel (150B) is preferably 0.2 to 1 mm, taking into account the outer diameter of the porous member and the size of the inner channel.

[0053] The outer horizontal channel (150B) may be horizontally connected to the inner channel (150A). To this end, a horizontal connecting channel (150C) may be provided to horizontally connect the inner channel (150A) and the outer horizontal channel (150B). The height (h3) of the horizontal connecting channel (150C) may be smaller than the height of the other channels. Alternatively, the height (h3) of the horizontal connecting channel (150C) may be equal to or greater than the height of the other channels.

[0054] Although the bottom surfaces of each channel (150A, 150B, 150C) in FIG. 2 are shown as being located on the same plane, the present invention is not limited thereto. The relative positions of the channels may change as long as they can be connected to each other.

[0055] As illustrated in FIG. 3, a plurality of trenches are defined by protrusions (120) in the inner wall of an insulating plate (110) forming a cooling gas passage. Such carved structures correspond to each channel (150A, 150B, 150C). The depths of the trenches may be the same or different, and accordingly, the heights of each channel may be the same or different.

[0056] As described above, the outer horizontal channel (150B) forms a continuously connected channel on the cross-section of the cooling gas channel. In the present invention, the outer horizontal channel (150B) extends along the outer edge of the porous member. Conventionally, when connected to a through hole from the porous member, it becomes difficult for He gas to pass through the outer edge of the porous member as the diameter of the hole decreases. In the present invention, by providing a continuous circulation channel on the outer edge of the channel, that is, on the outer edge of the porous member, the cooling gas is allowed to flow through the entire volume of the porous member, thereby increasing the flow rate of the cooling gas and enabling a uniform cooling gas flow throughout the entire porous member.

[0057] The horizontal connecting channel (150C) connects the inner channel (150A) and the outer horizontal channel (150B) laterally between the protrusions (120).

[0058] Figure 3 illustrates four horizontal connecting channels formed by four protrusions. However, the shape and number of the protrusions and horizontal connecting channels are exemplary, and it is obvious that various shapes and numbers of protrusions and horizontal connecting channels different from these can be designed.

[0059] FIG. 4 is a drawing illustrating horizontal channels according to another embodiment of the present invention.

[0060] Referring to FIG. 4, the Euro channels include an inner channel (150A), an outer horizontal channel (150B), and a horizontal connecting channel (150C). However, it differs from FIG. 3 in that two protrusions for forming the Euro channels are arranged to have 180-degree rotational symmetry.

[0061] FIG. 5 is a schematic diagram illustrating another example of forming a cooling gas flow path structure of the electrostatic chuck of the present invention, and FIG. 6 is a schematic perspective view illustrating a porous member used in the flow path structure of FIG. 5.

[0062] Referring to FIGS. 5 and 6, the porous member (140) has four protrusions (142) protruding from one surface. As described with reference to FIGS. 2 and 3, by forming the protrusions (142) on the porous member (140), an inner channel (150A), an outer horizontal channel (150B), and a horizontal connecting channel (150C) can be formed between the protrusions (142) and the wall surface of the cooling gas channel.

[0064] <Experimental Example>

[0065] A mold having a cylindrical groove with a diameter of 3.1 mm and a height of 2.7 mm was manufactured. Four fan-shaped protrusions with a height of 0.1 mm and through holes with a diameter of 0.2 mm were formed on the bottom of the mold to form an inner channel, a horizontal connecting channel, and an outer horizontal channel as described in relation to Fig. 3, and this was used as an experimental example to simulate the channel structure of the present invention.

[0066] Meanwhile, for comparison, a mold having the same cylindrical groove was manufactured and used as a comparative experimental example, except that no protrusions were formed on the bottom of the mold.

[0067] The flow rate was measured by flowing He through the molds of the fabricated experimental and comparative examples while varying the pressure. The average value was calculated after 20 measurements.

[0068] Table 1 below is a graph showing the results of measuring He flow rate according to He pressure.

[0070] division enter Average flow rate (L / min) Experimental Example 100 kPa 0.12 150 kPa 0.15 200 kPa 0.17 250 kPa 0.20 300 kPa 0.22 Comparative experiment example 100 kPa 0.53 150 kPa 0.68 200 kPa 0.82 250 kPa 0.97 300 kPa 1.11

[0071] From Table 1, it can be seen that the flow rate value of the experimental example is more than four times that of the comparative experimental example. In addition, it can be seen that this increase in flow rate increases with increasing He pressure.

[0072] As described above, the present invention has been explained by specific details such as specific components, limited embodiments, and drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. A person skilled in the art to which the invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the invention. Accordingly, the concept of the present invention should not be limited to the described embodiments, and all technical concepts that are equivalent to or have equivalent variations to the claims set forth below, as well as the claims themselves, should be interpreted as being included within the scope of the rights of the present invention. Explanation of the symbols

[0073] 100 electrostatic chuck 110 hereditary plates 120 protrusions 130 through holes 140 porous member 142 protrusion 150 Euro Channel 150A inner channel 150B outer horizontal channel 150C horizontal connection channel 200 bases 210 Cooling gas introduction furnace

Claims

Claim 1 An electrostatic chuck having a cooling gas channel for cooling a substrate on a dielectric plate through a base and a dielectric plate with a cooling gas, wherein the cooling gas channel comprises: a gas introduction channel provided in the base for supplying cooling gas; a through hole provided on the surface of the dielectric plate and communicating with the gas introduction channel; a porous member on the cooling gas channel between the gas introduction channel and the through hole; and a plurality of cooling gas channel channels provided between the porous member and the through hole, wherein the plurality of cooling gas channel channels include an inner channel connected to the through hole and an outer channel surrounding the outer edge of the inner channel, and the inner channel and the outer channel are in communication at least one side. Claim 2 In claim 1, the outer channel is an electrostatic chuck extending in a horizontal direction. Claim 3 An electrostatic chuck according to claim 1, wherein the inner channel and the outer channel are partitioned by a plurality of protrusions protruding from the inner wall of the cooling gas passage. Claim 4 In paragraph 3, the electrostatic chuck, wherein the plurality of protrusions are arranged with rotational symmetry with respect to the center of the cooling gas channel. Claim 5 An electrostatic chuck according to claim 1, wherein the inner channel and the outer channel are partitioned by a protrusion protruding from the porous member. Claim 6 An electrostatic chuck according to claim 1, wherein the plurality of protrusions are arranged with rotational symmetry with respect to the center of the cooling gas flow path. Claim 7 In claim 1, the electrostatic chuck, wherein the inner channel and the outer channel are connected in a horizontal direction. Claim 8 In claim 7, an electrostatic chuck having a horizontal connecting channel for communicating horizontally between the inner channel and the outer channel. Claim 9 In claim 8, the height of the outer channel is the same as the height of the horizontal connecting channel, an electrostatic chuck. Claim 10 In claim 8, the height of the outer channel is higher than the height of the horizontal connecting channel, an electrostatic chuck. Claim 11 In claim 8, the height of the outer channel is lower than the height of the horizontal connecting channel, an electrostatic chuck. Claim 12 An electrostatic chuck according to claim 1, wherein the width of the outer channel is 0.2 to 1 mm. Claim 13 A porous member having a predetermined volume and having a first surface and a second surface perpendicular to the flow of cooling gas, which is mounted in the cooling gas passage of an electrostatic chuck, wherein the porous member has a plurality of protrusions on the first surface or the second surface, and when mounted in the cooling gas passage, the plurality of protrusions come into contact with the cooling gas passage to partition an inner channel and an outer channel of the porous member, and the outer channel surrounds the outer edge of the inner channel. Claim 14 In Clause 13, the outer channel is a porous member extending in a horizontal direction. Claim 15 In claim 13, the plurality of protrusions are a porous member arranged with rotational symmetry with respect to the center of the cooling gas channel. Claim 16 In claim 13, the above-mentioned protrusion is a porous member having a height of 0.1 to 1 mm.

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