Mounting table and electrostatic chuck

Abstract

A mounting table 1 comprising: a base (2); a conductive layer (3) that is provided on at least a part of the outer surface of the base (2); and an insulating layer (4) that is provided on at least a part of the outer surface of the conductive layer (3) and is provided with a mounting surface (1a) on which a workpiece (W) is to be mounted, wherein the conductive layer (3) is exposed.

Description

Mounting Table and Electrostatic Chuck

[0001] The present invention relates to a mounting table and an electrostatic chuck.

[0002] Conventionally, as semiconductor manufacturing equipment, etching apparatuses that perform dry etching on an object by plasma have been used. In an etching apparatus, an electrostatic chuck is used to fix an object by using static electricity. Since the electrostatic chuck is used in a plasma atmosphere, an insulating layer having plasma resistance is provided (Japanese Unexamined Patent Publications JP 2008-66707 A (JP2008-66707A) and JP 2003-60020 A (JP2003-60020A)).

[0003] Although the insulating layer described in the above patent document improves heat resistance, durability, etc., it is required to also consider the current-carrying part for applying a voltage to the electrode.

[0004] An object of the present invention is to provide a mounting table and an electrostatic chuck excellent in durability while ensuring electrical characteristics.

[0005] The mounting table of the present disclosure is a mounting table comprising: a base; a conductive layer provided on at least a part of an outer surface of the base; and an insulating layer provided on at least a part of an outer surface of the conductive layer, the insulating layer having a mounting surface on which an object to be mounted is placed, wherein the conductive layer is exposed in the mounting table.

[0006] In the mounting table of the present disclosure, when the mounting table is viewed from a direction perpendicular to the mounting surface, the conductive layer may be exposed on an outer periphery of the mounting table.

[0007] In the mounting table of the present disclosure, when the mounting table is viewed from a direction perpendicular to the mounting surface, the exposed conductive layer may spread in an annular shape.

[0008] The mounting table of the present disclosure has one or more mounting surfaces having different heights from a lower surface that is a surface of the base opposite to the conductive layer, and the exposed conductive layer, and a height from the lower surface of the base to an exposed upper surface of the conductive layer may be lower than a height from the lower surface of the base to the one or more mounting surfaces.

[0009] In the mounting base of the present disclosure, on the surface in which the conductive layer is exposed, the conductive layer has a recess in which the insulating layer is laminated, and the height from the lower surface of the base to the upper surface in which the conductive layer is exposed may be at least a portion higher than the height from the lower surface of the base to the upper surface of the insulating layer in the recess.

[0010] In the mounting base of this disclosure, the insulating layer may be formed continuously across the plurality of mounting surfaces so as to be along the outer surface of the mounting base described above.

[0011] In the mounting platform of this disclosure, the insulating layer may include a resin.

[0012] In the mounting platform of this disclosure, the insulating layer includes a resin layer and a plasma-resistant layer, and the plasma-resistant layer may be laminated on the outer surface side of the resin layer.

[0013] In the mounting platform of this disclosure, the resin layer may extend from the plasma-resistant layer.

[0014] The mounting platform of this disclosure may include an intermediate layer between the resin layer and the plasma-resistant layer.

[0015] In the mounting platform of this disclosure, the resin layer may include polyimide.

[0016] In the mounting platform of this disclosure, the plasma-resistant layer may include ceramics.

[0017] The electrostatic chuck of this disclosure is an electrostatic chuck equipped with the above-described mounting base, characterized in that an electrode is provided between the mounting surface and the base.

[0018] This is a cross-sectional view showing an exemplary schematic configuration of a mounting base according to an embodiment of the present disclosure. This is a diagram showing an example of use of the mounting base according to an embodiment of the present disclosure. This is a perspective view of an exemplary mounting base according to an embodiment of the present disclosure. This is a cross-sectional view of an exemplary electrostatic chuck according to an embodiment of the present disclosure to which a conductive member, an edge ring, and a workpiece are attached. This is a schematic top view (a) and cross-sectional view (b) of the electrostatic chuck of Example 1. This is a cross-sectional view for a more detailed explanation of the electrostatic chuck of Example 1. This is a top view (a) and cross-sectional view (b) for explaining the dimensions of the base of Example 1. This is a schematic top view (a) and cross-sectional view (b) of the electrostatic chuck of Modification 1 of Example 1. This is a schematic top view (a) and cross-sectional view (b) of the electrostatic chuck of Modification 2 of Example 1.

[0019] Embodiments of the present disclosure will be described below with reference to the drawings, but the inventions of the present disclosure are not limited thereto.

[0020] [Mounting platform 1] As shown in Figure 1, the mounting platform 1 comprises a base 2, a conductive layer 3, and an insulating layer 4. The conductive layer 3 is provided on at least a portion of the outer surface of the base 2, and the insulating layer 4 is provided on at least a portion of the outer surface of the conductive layer 3. The insulating layer 4 is provided with a mounting surface 1a on which the object to be mounted W is placed. The conductive layer 3 is exposed on the mounting platform 1. In this specification, the "mounting surface" refers to the surface of the mounting platform 1 opposite to the lower surface 2b of the base 2 (mounting platform 1), and more specifically, not only the upper surface of the insulating layer 4 (e.g., 1a1, 1a2) but also the upper surface 1a3 of the conductive layer 3 can be the mounting surface (see Figures 1(A) and 1(B)). Furthermore, the "outer surface" refers to the surface of the member being described defined from other members, and is not limited to surfaces in contact with an external atmosphere such as air or plasma. Furthermore, for convenience, for example, the vertical direction in Figure 1(A) (i.e., the direction from the base 2 towards the insulating layer 4) is referred to as the "vertical direction," and the left-right direction in Figure 1(A) that is perpendicular to this vertical direction is referred to as the "horizontal direction."

[0021] As shown in Figure 1(B), the mounting base 1 may have one or more mounting surfaces and exposed conductive layers 3 (i.e., multiple upper surfaces 1a1, 1a2, 1a3 of different heights) at different heights from the surface (bottom surface 2b) opposite to the conductive layer 3 of the base 2, depending on the application. For example, if there are three upper surfaces, the conductive layer 3 can be exposed on the lowest upper surface 1a3 among the multiple upper surfaces 1a1, 1a2, 1a3 (the mounting base 1 has a surface with the conductive layer 3 exposed). As shown in the examples in Figures 3 and 4, the uppermost surface (the upper surface with the highest height from the lower surface 2b of the base 2) 1a1 is used as a mounting surface for placing an object to be mounted (a component to be processed) W such as a wafer, the middle upper surface 1a2 is used as a mounting surface for placing an edge ring ER, and the lowest upper surface (the upper surface with the lowest height from the lower surface 2b of the base 2, the surface with the conductive layer 3 exposed) 1a3 may be used as a connection surface (current-carrying surface, connection terminal) connected to a power source (not shown; for example, a high-frequency power source) via a conductive member C. In this way, the height from the lower surface 2b of the base 2 to the upper surface 1a3 with the conductive layer 3 exposed can be lower than the height from the lower surface 2b of the base 2 to one or more mounting surfaces 1a1, etc. Note that the mounting stand 1 (base 2) may have three or more upper surfaces 1a. The objects to be placed on the mounting surface of the mounting table 1 are not limited to the workpiece W, edge ring ER, and conductive member C, but can be selected according to the application, such as the display manufacturing process, semiconductor manufacturing process, and plasma processing process.

[0022] (Base 2) The base 2 constitutes the main body of the mounting base 1 and can hold the workpiece W (see Figure 4). The base 2 may also have a cooling function, and Figure 4 shows holes for passing heat transfer gas as flow channels. Note that the "workpiece W" is not particularly limited and may include, for example, wafers (silicon wafers, quartz wafers, SiC wafers, etc.), flat panel display (FPD) panels and substrates, metal members, film members, resin members (automotive interior materials, etc.), glass members, and other workpieces.

[0023] Since the mounting stage 1 can be used as an electrostatic chuck in dry etching and CVD processes in semiconductor manufacturing processes using plasma or other reactive gases, it is preferable that the material of the base 2 is resistant to such atmospheres. For example, the base 2 can be a ceramic substrate (alumina, aluminum nitride, yttrium oxide, silicon carbide, etc.), a resin substrate, or a metal substrate made of aluminum or stainless steel. From the viewpoint of plasma resistance and heat resistance, polyimide, polyamide, polyamide-imide, aromatic polyether ketone, fluorine polymer, etc. are preferred for the resin substrate. The base 2 may also be a substrate composed of two or more types. From the viewpoint of plasma resistance and heat resistance, it is preferable that the base 2 be a metal substrate, a ceramic substrate, a resin substrate, or a composite substrate made of ceramics and resin. From the viewpoint of low thermal expansion and high thermal conductivity, it is particularly preferable that the material of the base 2 be aluminum, stainless steel, alumina, aluminum nitride, yttrium oxide, or silicon carbide.

[0024] The shape of the base 2 is not limited and can be disc-shaped, circular, cylindrical, or rectangular to match the shape of the workpiece W, edge ring ER, conductive member C, etc. The shape, material, thickness, etc. of the base 2 can be appropriately designed and modified according to the application. The dimensions of the base 2 can also be appropriately set according to the workpiece W, but are not particularly limited. Even if the mounting table 1 has multiple top surfaces, the shape and thickness (height), etc. of the base 2 at each stage can be appropriately designed and modified according to the application.

[0025] (Conductive Layer 3) The conductive layer 3 can function as an energizing part. The conductive layer 3 can contact a conductive member C connected to a power source, as described later, and supply current to electrodes such as the electrode 6 for adsorbing the workpiece W and the electrode 7 for adsorbing ER via an electrical circuit (not shown) (Figure 4). Metal can be used as the material for the conductive layer 3, and from the viewpoint of conductivity, aluminum, stainless steel, gold, silver, copper, tungsten, and nickel are particularly preferred. The material of the conductive layer 3 and the material of the base 2 may be the same or different. If the material of the conductive layer 3 and the material of the base 2 are the same, the conductive layer 3 and the base 2 may be integrated. For example, if the material of the base 2 is aluminum, the outer surface of the base 2 can also serve as the conductive layer 3 made of aluminum. That is, the entire base 2 can perform the function of holding the workpiece W, and a part of the base 2 may function as the conductive layer 3. In this specification, the "conductive layer" is defined as having an electrical resistivity of 10, measured in accordance with, for example, JIS C2525:1999 and JIS K 7194:1994. -8 Ω・cm~10 -4 It is preferable that the resistivity is Ω·cm. The method for measuring electrical resistivity in this invention is not particularly limited.

[0026] As described above, the conductive layer 3 is provided on at least a portion of the outer surface of the base 2. In one embodiment, the exposed conductive layer 3 is preferably annular when viewed from the direction perpendicular to the mounting surface 1a (in a plan view) (Figure 5). The conductive layer 3 may be formed to cover the entire surface of the base 2 from the center outwards (in a planar manner), or it may be formed to spread radially from the center outwards (Figure 8).

[0027] In one embodiment, when the mounting base 1 is viewed from a direction perpendicular to the mounting surface 1a, the conductive layer 3 may be exposed on the outer circumference of the mounting base 1. In other words, it is preferable that the conductive layer 3 is exposed at the outer peripheral end of the upper surface 1a of the mounting base 1, and that the conductive layer 3 is covered by the insulating layer 4 on the inner circumference side of the upper surface 1a (Figures 1, 2, and 6).

[0028] As will be described later, on the surface 1a of the mounting base 1 where the conductive layer 3 is exposed, the conductive layer 3 may be provided with a recess (counterbore) 3c in which the insulating layer 4 is formed (laminated). Preferably, the height from the lower surface 2b of the base 2 to the exposed upper surface 1a (1a3) of the conductive layer 3 is at least partially higher than the height from the lower surface 2b of the base 2 to the upper surface of the insulating layer 4 in the recess 3c (Figure 2).

[0029] (Insulating layer 4) The insulating layer 4 allows the mounting base 1 to exhibit durability while ensuring electrical properties. The material of the insulating layer 4 is not particularly limited, but may include resin materials or inorganic materials. If it is made of resin material, when the mounting base 1 is heated by plasma treatment or the like, damage to the mounting base 1 can be prevented by the relaxation of thermal stress, and as a result, durability can be ensured. Examples of resin materials include polyimide, polyolefin, aromatic polyether, and fluororesin. If it is made of inorganic material, durability (plasma resistance) can be ensured when the mounting base 1 is exposed to a plasma atmosphere. Examples of inorganic materials include those containing at least one of yttrium, aluminum, zirconium, calcium, magnesium, nickel, titanium, and glass (silicon glass), and may also be oxides, hydroxides, carbon materials, or mixtures thereof (minerals, etc.), and the mixture may include hydrotalcite and hydroxyapatite. For example, when formed from aluminum oxide, the insulating layer 4 can be formed by thermal spraying, aluminum anodizing (anodizing treatment), etc.

[0030] The insulating layer 4 preferably includes a resin layer 41 and a plasma-resistant layer 42. By laminating the plasma-resistant layer 42 on the outer side of the resin layer 41 (Figure 1(C)), the plasma resistance and durability of the mounting base 1 can be more reliably ensured. Here, "outer side" refers to the side facing the atmosphere, i.e., the side opposite to the base 2.

[0031] The mounting base 1 has multiple, for example, three upper surfaces 1a1, 1a2, and 1a3. These upper surfaces are arranged in the order of upper surfaces 1a1, 1a2, and 1a3 from the central side (i.e., the inner circumference side) to the outer circumference side of the mounting base 1, and the height from the lower surface 2b to the upper surface 1a decreases in the order of 1a1, 1a2, and 1a3 (Figures 1(B) to (E)). In such cases, the plasma-resistant layer 42 may extend along the outer surface of the mounting base 1 to at least a portion of the side surface adjacent to the lowest upper surface 1a3 on the central side (i.e., the inner circumference side) of the mounting base 1 (also adjacent to upper surface 1a2) (Figures 1(C) and (D), and the vertical direction in Figure 2). That is, the plasma-resistant layer 42 may be formed continuously along the outer surface from the upper surface 1a1 to at least a portion of the side surface adjacent to the upper surface 1a3 where the conductive layer 3 is exposed and the central side of the mounting base 1. For example, in Figure 1(D), the plasma-resistant layer 42 extends vertically along the side surface of the base 2 (second stage) on the inner circumference side of the upper surface 1a3, but the extent to which the tip of the plasma-resistant layer 42 extends along the side surface of the base 2 (second stage) is not limited. In the example shown in Figure 1(C), the tip of the plasma-resistant layer 42 extends to cover all sides of the base 2 (second stage) and the resin layer 41. In this way, the insulating layer 4 may be formed continuously across multiple mounting surfaces (1a1, 1a2, 1a3) along the outer surface of the mounting base 1.

[0032] In the left-right direction in Figures 1(E) and 2, the resin layer 41 may extend from the plasma-resistant layer 42. This prevents a portion of the plasma-resistant layer 42 from peeling off or chipping away from the mounting base 1. Even if a portion of the plasma-resistant layer 42 peels off or chips away from the mounting base 1, the resin layer 41 can minimize the impact on the durability of the mounting base 1. Furthermore, if the resin layer 41 has higher thermal stress resistance than the plasma-resistant layer 42 among the insulating layers 4, the peeling or chipping of the plasma-resistant layer 42 from the mounting base 1 is suppressed. As a result, the insulating layer 4 is maintained, and when the conductive layer 3 is electrically connected to the conductive member C as shown in Figure 2, the mounting base 1 can maintain good electrical characteristics.

[0033] The upper part of the end of the resin layer 41 can be lower than the upper surface (1a3) of the exposed conductive layer 3 (Figure 2, bottom). That is, the height from the bottom surface 2b to the upper part of the end of the resin layer 41 may be lower than the height from the bottom surface 2b to the exposed upper surface (1a3) of the conductive layer 3, and the upper part of the resin layer 41 in the recess 3c may be closer to the bottom surface 2b of the base 2 than the upper surface (1a3) of the exposed conductive layer 3. Furthermore, the recess (shape of the resin layer 41 in the recess 3c) formed by the resin layer 41 provided on the upper surface 1a3 of the mounting base 1 and the resin layer 41 provided on the side surface of the mounting base 1 adjacent to the upper surface 1a3 can be a curved surface (Figure 2). Although not shown, a plasma-resistant layer 42 may be formed to cover this recess 3c.

[0034] Examples of materials for the resin layer 41 include those described above, with polyimide being particularly preferred. While there are no particular limitations on the material for the plasma-resistant layer 42 as long as it is a plasma-resistant material, inorganic materials, particularly ceramics, are preferred. Among ceramics, alumina, yttria, and aluminum nitride are particularly preferred.

[0035] The thickness of the resin layer 41 is preferably 10 to 500 μm. With this thickness, the function of the mounting base 1 (adsorption to the object to be mounted in the case of an electrostatic chuck) can be maintained while ensuring dielectric strength (insulation). The thickness of the plasma-resistant layer 42 is preferably 10 to 1000 μm. With this thickness, the function of the mounting base 1 (adsorption to the object to be mounted in the case of an electrostatic chuck) can be maintained while ensuring plasma resistance (durability). If there is a difference in dielectric strength between the resin layer 41 and the plasma-resistant layer 42, it is preferable that the thickness of the layer with the lower dielectric strength is not excessively large.

[0036] Preferably, the storage modulus of the resin layer 41 at room temperature (25°C) is 100 to 10,000 MPa. Having a storage modulus at room temperature below the above upper limit allows for the mitigation of thermal stress caused by heating, even when the mounting base 1 is heated by plasma treatment or the like, thus preventing damage to the mounting base 1 and ensuring durability. Furthermore, having a storage modulus at room temperature above the above lower limit suppresses damage to the mounted object and ensures the durability of the mounting base 1.

[0037] The storage modulus of the resin layer 41 can be measured, for example, using the dynamic viscoelasticity measurement method (DMA method). Specifically, the resin layer 41 is cut to a predetermined size, and measured using a dynamic viscoelasticity measuring device (DMA850 manufactured by TA Instruments Inc.) under conditions of a frequency of 10 Hz, a heating rate of 5°C / min, and a nitrogen atmosphere. The value of the storage modulus at 25°C can then be read and used as the measured value.

[0038] (Intermediate layer 5) The mounting base 1 may have an intermediate layer 5 between the resin layer 41 and the plasma-resistant layer 42. The intermediate layer 5 is not particularly limited and may have functions such as bonding, adhesion (fixing), stress relief, insulation, heat insulation, and heat conduction (hereinafter also referred to as the "functional layer"), or it may be a filler or space that is not intended to have any function. Therefore, the material of the intermediate layer 5 is not limited.

[0039] The adhesion layer, which is one of the functional layers, can bond (adhere) the resin layer 41 and the plasma-resistant layer 42. The intermediate layer 5 as the adhesion layer is particularly preferable when there is a large difference in thermal expansion between the resin layer 41 and the plasma-resistant layer 42. The material of the adhesion layer is not particularly limited, and adhesive materials can be used. Examples of adhesive materials include inorganic materials, resin materials, and mixtures thereof. More specifically, examples include brazing materials (silver brazing, copper brazing, copper alloys, aluminum brazing, nickel brazing, activated silver brazing, titanium brazing, soldering materials, etc.), silane compounds, resin glass, silicone resin, fluororesin, acrylic resin, polyimide resin, polyamide resin, polyester resin, polyolefin resin, and mixtures of these adhesive materials with fillers. From the viewpoint of adhesion and heat resistance, silane compounds, resin glass, silicone resin, fluororesin, acrylic resin, polyimide resin, and mixtures of these adhesive materials with fillers are preferred, and mixtures of silane compounds and resin glass with fillers are even more preferred, but the material is not limited to these. The appropriate metal material or adhesive material can be selected as needed based on the relationship between the properties (thickness, thermal expansion, thermal conductivity, etc.) of the resin layer 41 and the plasma-resistant layer 42.

[0040] [Electrostatic Chuck] The present disclosure provides an electrostatic chuck equipped with a mounting table 1 as described above. As shown in the example in Figure 4, the electrostatic chuck according to the present disclosure further includes electrodes between the upper surface 1a (including the mounting surface 1a1) of the mounting table 1 and the base 2. For example, electrodes may be provided between the mounting surface 1a and the conductive layer 3, or the electrodes may be provided inside the base 2.

[0041] Examples of "electrodes" include electrodes such as a workpiece adsorption electrode 6 for adsorbing the workpiece W, an ER adsorption electrode 7 for adsorbing the edge ring ER, and a plasma generation electrode. In the electrostatic chuck according to this embodiment, a voltage is applied to electrodes 6 and 7 to generate an electrostatic force (Coulomb force), which can then adsorb the workpiece W and the edge ring ER onto the mounting base 1.

[0042] These electrodes are not particularly limited as long as they are made of a conductive material that can exhibit electrostatic adsorption force when a voltage is applied. For example, thin films made of metals such as copper, aluminum, gold, silver, platinum, chromium, nickel, tungsten, and stainless steel, and thin films made of at least two metals selected from the above metals are preferably used, and ceramic materials may also contain such conductive materials. Examples of such conductive material thin films include those formed by vapor deposition, plating, sputtering, thermal spraying, etc., those formed by applying and drying a conductive paste, and metal foils such as copper foil.

[0043] Furthermore, a plurality of protrusions 8 may be provided on the surface of the mounting table 1 on the side holding the member to be processed W (that is, the mounting surface, the upper surface 1a, including the base 2) (FIGS. 3 and 4). By holding (adsorbing) the member to be processed W on the upper surfaces of these protrusions 8, the contact area between the mounting table 1 and the member to be processed W is reduced. As a result, the quality of the member to be processed W (such as reduction of particle adhesion to a wafer) can be maintained, and the durability of the electrostatic chuck can be ensured. The number, arrangement, shape, height, dimensions, etc. of the protrusions 8 are not particularly limited. From the viewpoint of maintaining the quality of the member to be processed W, the shape of the protrusions 8 is preferably disk-shaped, columnar, or cylindrical, and one or more fine protrusions (not shown) may be further provided on the upper surface of each protrusion 8. The upper surfaces of each protrusion 8 and the fine protrusions are preferably flat. If the shape, height, etc. of the protrusions 8 and the fine protrusions are as described above, an electrostatic chuck that maintains good quality of the member to be processed W and ensures higher durability can be provided.

[0044] [Other: Plasma Processing Apparatus] Although not shown, as one embodiment of the present disclosure, a plasma processing apparatus including the above-described electrostatic chuck can be provided. The plasma processing apparatus can include the above-described conductive member C and edge ring ER.

[0045] (Conductive Member C) The conductive member C is connected to, for example, a high-frequency power supply not shown. When the conductive member C comes into contact with the conductive layer 3, current from the high-frequency power supply flows to the conductive layer 3, and power is supplied to the electrodes 6, 7, etc. (FIGS. 2 and 4). The high-frequency power supply may be, for example, a power supply for plasma generation or plasma control.

[0046] In addition to the conductive characteristics as described above, since the conductive member C is exposed to a plasma atmosphere, plasma resistance is required. Therefore, the portion of the conductive member C exposed to the plasma atmosphere can be formed from the materials listed as the material of the plasma-resistant layer 42, and the portion functioning as the current-carrying part of the conductive member C can be formed from the materials listed as the material of the conductive layer 3.

[0047] (Edge Ring ER) Edge Ring ER, also called a focus ring (FR), is used to uniformly perform plasma treatment on a member to be processed W such as a wafer adsorbed on the upper surface 1a (1a1) of an electrostatic chuck (mounting table 1). The edge ring ER is formed so as to surround the outer periphery of the electrostatic chuck, and can be formed in a ring shape (including an arc shape).

[0048] The material of the edge ring ER is not particularly limited, and examples thereof include semiconductors, conductors, insulators, and combinations of two or more of these. By using a desired combination of these materials, dielectric properties can be controlled, and uniform plasma treatment can be performed on the member to be processed W adsorbed on the upper surface 1a of the electrostatic chuck.

[0049] [Manufacturing method and use of mounting table 1 and electrostatic chuck] The mounting table 1 and the electrostatic chuck can be manufactured, for example, as follows. First, the base 2 is prepared. In this case, when the base 2 is formed of a conductive material as described above, a part of the base 2 may be used as the conductive layer 3, or the conductive layer 3 may be formed by patterning a metal such as copper on the base 2.

[0050] Next, a resin layer 41 is formed on the surface of the conductive layer 3 (base 2) excluding a part thereof. The method for forming the resin layer 41 is not particularly limited, and the resin layer 41 may be formed by a coating method (spray method, casting method, etc.), a resin molding method using a mold, or the like. Alternatively, a resin film (sheet-shaped resin layer 41) may be laminated on the surface of the conductive layer 3 and formed by interposing an adhesive (adhesive sheet) as necessary (lamination method).

[0051] Furthermore, an intermediate layer 5 such as electrodes 6, 7 or an adhesion layer may be formed around the resin layer 41. The electrodes 6 and 7 may be formed by laminating copper foil or the like, and can also be formed using a coating method, a plating method, or a thermal spraying method. The intermediate layer 5 can be formed by a coating method (spray method, casting method, etc.), a method of laminating an already formed intermediate layer 5 (for example, an adhesive sheet), or the like.

[0052] If the mounting base 1 is an electrostatic chuck, a conductive layer 3 is provided between the base 2 and the mounting surface 1a. For example, a conductive layer 3 may be formed on one side of a polyimide film (insulating film) using a plating method, and a laminate A (Figure 6) formed by laminating an adhesive layer 5a and a polyimide film on this conductive layer 3 in that order may be laminated on the surface of the resin layer 41 to form a conductive layer 3 and an intermediate layer 5.

[0053] Subsequently, the mounting base 1 and the electrostatic chuck can be manufactured by forming the plasma-resistant layer 42 to a desired thickness. The method for forming the plasma-resistant layer 42 is not particularly limited, but examples include coating methods (spray method, casting method, thermal spray method) and methods for bonding an already formed plasma-resistant layer 42 (adhesion method).

[0054] The mounting table 1 and electrostatic chuck according to this embodiment can be used to attract a workpiece W by applying a voltage to the electrodes. For example, the electrostatic chuck can be used to attract wafers (workpiece W) and display components in dry etching and CVD processes in semiconductor manufacturing processes, and in display manufacturing processes.

[0055] According to the mounting table 1 and electrostatic chuck of this embodiment, which have the above configuration, the mounting table 1 comprises a base 2, a conductive layer 3 provided on at least a part of the outer surface of the base 2, and an insulating layer 4 provided on at least a part of the outer surface of the conductive layer 3, with a mounting surface 1a on which the object to be mounted W is placed, wherein the conductive layer 3 is exposed (Figure 1(A)). In addition, in an electrostatic chuck which is one embodiment of the present disclosure, electrodes 6 and 7 are provided between the mounting surface 1a of the mounting table 1 and the base 2 (see Figure 4).

[0056] According to the mounting table 1 and electrostatic chuck of this embodiment, power can be supplied to the electrodes 6 etc. via the exposed conductive layer 3 while the workpiece W is placed on the mounting table 1. The mounting table 1 can exhibit durability while ensuring electrical characteristics thanks to the insulating layer 4. Furthermore, in the electrostatic chuck of this disclosure, it is preferable to provide electrodes 6 and 7 between the insulating layer 4 (plasma-resistant layer 42) and the conductive layer 3. As a result, electrodes 6 and 7 can be easily connected to the power supply without going through the inside of the base 2, and as a result, an electrostatic chuck with good productivity and electrical characteristics can be obtained.

[0057] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, when the mounting table 1 is viewed from a direction perpendicular to the mounting surface 1a, the conductive layer 3 may be exposed on the outer circumference of the mounting table 1. This allows the electrodes 6 and the power supply to be connected using the exposed conductive layer 3, rather than inside the mounting table 1 or electrostatic chuck. As a result, there is no need to form a complex electrical circuit inside the electrostatic chuck, which is preferable from the viewpoint of productivity.

[0058] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, when the mounting table 1 is viewed from a direction perpendicular to the mounting surface 1a (top view), it is preferable that the exposed conductive layer 3 spreads out in an annular shape. By increasing the area of ​​the exposed portion of the conductive layer 3 in this way, power supply to the electrodes 6 and the like can be ensured. Also, when the exposed conductive layer 3 is viewed from the top surface of the electrostatic chuck, it is preferable that it spreads out evenly with the same width (specifically, Figures 2 and 3). In this way, power supply to the electrodes can be made uniform. Furthermore, as a modification of this embodiment, the exposed conductive layer 3 may be arranged so that there is no bias in the position of the conductive layer 3 when viewed from the top surface of the electrostatic chuck. For example, the conductive layer 3 may be arranged at multiple positions relative to the center of the electrostatic chuck (Figure 8, Modification 1), or it may be arranged at multiple positions symmetrically or asymmetrically in the vertical or horizontal directions in the drawing. Also, the conductive layer 3 may be arranged so as to be surrounded by the insulating layer 4 (Figure 9, Modification 2), or the conductive layer 3 and the insulating layer 4 may be arranged alternately in concentric circles with random widths.

[0059] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the mounting table 1 has one or more mounting surfaces 1a (1a1, 1a2) at different heights from the bottom surface 2b, which is the surface of the base 2 opposite to the conductive layer 3, and an exposed conductive layer 3 (mounting surface 1a3). The height from the bottom surface 2b of the base 2 to the exposed upper surface (mounting surface 1a3) of the conductive layer 3 may be lower than the height from the bottom surface 2b of the base 2 to the one or more mounting surfaces 1a (1a1, 1a2) (Figure 1(B)). As described above, not only can a workpiece W such as a wafer be placed on it, but an edge ring ER can also be placed on it, and conductivity for plasma processing can be achieved at the bottom layer. In this way, the mounting table 1 and electrostatic chuck can be used in various forms (applications).

[0060] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the insulating layer 4 may contain resin. This resin can be formed using, for example, a coating method (spray method, casting method, etc.). Since the resin has high insulating properties and the coating method can form a uniform insulating layer 4, it is suitable for demonstrating the durability (insulating properties) of the mounting table 1 even in a plasma environment.

[0061] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the insulating layer 4 preferably includes a resin layer 41 and a plasma-resistant layer 42, with the plasma-resistant layer 42 laminated on the outer surface side of the resin layer 41. The resin layer 41 may also extend from the plasma-resistant layer 42. Such a laminated structure ensures the durability (plasma resistance, thermal stress resistance) of the mounting table 1.

[0062] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the plasma-resistant layer 42 may extend continuously along the outer surface of the mounting table 1 from the center of the mounting table 1 to at least a portion of the side surface adjacent to the lowest upper surface 1a3 among the multiple upper surfaces 1a1, 1a2, and 1a3 on the central side of the mounting table 1. The insulating layer 4 may be formed continuously across the multiple mounting surfaces 1a1, 1a2, and 1a3 so as to be along the outer surface of the mounting table 1. This forms an insulating layer without seams (breaks), ensuring the durability of the mounting table 1. If there are seams (breaks), the mounting table 1 may be damaged starting from these seams.

[0063] Furthermore, in the mounting base 1 and electrostatic chuck of this embodiment, on the surface 1a (1a3) of the mounting base 1 where the conductive layer 3 is exposed, the conductive layer 3 has a recess 3c on which the insulating layer 4 is laminated, and the height from the lower surface 2b of the base 2 to the exposed upper surface 1a (1a3) of the conductive layer 3 can be made at least partially higher than the height from the lower surface 2b of the base 2 to the upper surface of the insulating layer 4 in the recess 3c. This is preferable because the connection between the conductive member C and the conductive layer 3 is not hindered by the above shape.

[0064] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the recess (shape of the resin layer 41 in the recess 3c) formed by the resin layer 41 provided on the upper surface 1a3 of the mounting table 1 and the resin layer 41 provided on the side surface of the mounting table 1 adjacent to the upper surface 1a3 may be curved. This is preferable because it reduces the risk of the resin layer 41 peeling off from the mounting table 1.

[0065] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, an intermediate layer 5 may be provided between the resin layer 41 and the plasma-resistant layer 42. The intermediate layer 5 is not particularly limited, but may be formed from a polymer material containing carbon elements in its main chain, or it may be formed from a polymer material that does not contain carbon elements in its main chain. For example, if the intermediate layer 5 has the function of adhering the resin layer 41 and the plasma-resistant layer 42 to close contact, it is possible to prevent the plasma-resistant layer 42 from peeling off from the resin layer 41, thereby improving the durability of the mounting table 1 and the electrostatic chuck. In addition, if the intermediate layer 5 is formed from resin, functions and effects such as stress relaxation, insulation, and heat insulation can also be expected.

[0066] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, the resin layer 41 preferably contains polyimide. Such a resin layer 41 ensures durability (heat resistance, plasma resistance).

[0067] Furthermore, in the mounting table 1 and electrostatic chuck of this embodiment, it is preferable that the plasma-resistant layer 42 includes ceramics. Such a plasma-resistant layer 42 further improves durability (plasma resistance, heat resistance).

[0068] However, the mounting base 1 and electrostatic chuck according to this embodiment are not limited to the above-described configurations or combinations.

[0069] For example, although a configuration in which the mounting base 1 has upper surfaces 1a1, 1a2, and 1a3 has been described, if an edge ring ER is not used, the mounting base 1 (electrostatic chuck) may have only upper surfaces 1a1 and 1a3.

[0070] Alternatively, the conductive layer 3 may be exposed from the side or bottom surface of the mounting base 1 (base 2) instead of the upper surface 1a of the mounting base 1 to supply power.

[0071] The present disclosure will be described in more detail below with reference to examples.

[0072] [Manufacturing method for electrostatic chucks]

[0073] (Example 1) An electrostatic chuck of Example 1 shown in Figure 5 was fabricated. First, a laminate containing electrode 6 (same configuration as laminate A in Figure 6) was fabricated as follows. Specifically, an electrode layer (electrode) 6 was formed by copper plating to a thickness of 10 μm on one side of a polyimide film (product name: Kapton, manufactured by Toray DuPont, insulating film) PF1 with a film thickness of 12.5 μm. A curable adhesive sheet (adhesive layer 5a) was laminated on this electrode 6. This adhesive sheet was prepared by mixing and dissolving 27 parts by mass of bismaleimide resin, 3 parts by mass of diaminosiloxane, 20 parts by mass of resolphenol resin, 10 parts by mass of biphenyl epoxy resin, and 240 parts by mass of ethyl acrylate-butyl acrylate-acrylonitrile copolymer in an appropriate amount of tetrahydrofuran, forming it into a sheet, and drying to remove the tetrahydrofuran. Subsequently, a polyimide film PF2 of the same type as described above was attached to this adhesive sheet, and a laminate was obtained by heat treatment (180°C, 30 minutes) to bond them together (the adhesive sheet hardened due to the heat treatment, forming an adhesive layer 5a). The thickness of the adhesive layer 5a was made to be 10 μm.

[0074] Next, a thermosetting polyimide varnish (Fine Chemical Japan, FC-114) was applied to the outer surface of the aluminum base 2, which has the dimensions shown in Figure 7, using a spray method so that the thickness after drying and curing would be 50 μm (in this example, a portion of the outer surface of the aluminum base 2 (the upper surface in Figure 6) functions as the conductive layer 3). The base 2 was placed in a high-temperature circulating dryer set to 250°C for 24 hours to form a polyimide layer (resin layer 41) along the upper surface of the base 2, as shown in Figure 6. The upper surface of the base 2 (Figure 7) is formed such that the length between the surface 1a3 where the conductive layer 3 (base 2) is exposed and the lower surface 2b of the electrostatic chuck (mounting table 1, base 2) is greater than the length between the resin layer 41 and the lower surface 2b, as shown in Figure 6.

[0075] Subsequently, laminate A (circular, 298 mm in diameter) was cut from the above laminate, and the adhesive sheet prepared as described above was separately laminated onto the surface of the polyimide film PF2 in laminate A. Then, laminate A was attached to the uppermost surface 1a1 of the base 2 and bonded by heat treatment (180°C, 30 minutes) (the adhesive sheet hardened due to the heat treatment, forming an adhesive layer 5b). The thickness of the adhesive layer 5b was 10 μm.

[0076] Next, 200 parts by mass of an inorganic filler consisting of 100 parts by mass of polysilazane and alumina (manufactured by Fujimi Incorporated, WA#4000, average particle size: 3 μm) were mixed with butyl acetate as a diluent, and the inorganic filler was then uniformly dispersed using an ultrasonic disperser to produce a paint.

[0077] Next, the paint was sprayed onto the upper surface 1a of the electrostatic chuck (excluding the exposed surface of the conductive layer 3), and then heated and dried to form an intermediate layer (adhesion layer) 5 as shown in Figure 6. The thickness of the intermediate layer 5 after drying was 10 μm.

[0078] Next, alumina powder (average particle size: 8 μm) was sprayed onto the upper surface of the intermediate layer 5 using a plasma spraying method to form a 50 μm thick ceramic underlayer (plasma-resistant layer 42) as shown in Figure 6.

[0079] Next, after applying a mask of a predetermined shape to the surface of the plasma-resistant layer 42, alumina powder (average particle size: 8 μm) was thermal sprayed onto the surface of the plasma-resistant layer 42 to form a ceramic surface layer (protrusions 8) with a thickness of 15 μm as shown in Figure 6.

[0080] Next, the adsorption surface of the ceramic surface layer that adsorbs the adsorbed material W was planar-ground with a diamond grinding wheel to obtain an electrostatic chuck (Figures 5 and 6). In the figures, "W" represents the material to be processed, "ER" represents the edge ring, and "C" represents the conductive member; these are illustrative examples and the actual shapes, arrangements, dimensions, proportions, etc., are not limited.

[0081] (Modifications 1 and 2) Modifications 1 and 2 of the electrostatic chuck of Example 1 were manufactured to have the configurations shown in Figures 8 and 9. Compared to the electrostatic chuck of Example 1, in which the resin layer 41 is formed in an annular shape on the inside of the upper surface 1a3 as shown in Figure 5(a), the electrostatic chucks of Modifications 1 and 2 differ in the arrangement and configuration of the polyimide layer (resin layer 41) on the upper surface 1a3.

[0082] Specifically, in Modification 1, the resin layer 41 is formed radially on the upper surface 1a3 (Figure 8(a)). In other words, the conductive layer 3 is also arranged at multiple positions relative to the center of the electrostatic chuck. This allows for the formation of an even circuit while ensuring insulation, thus achieving both conductivity and insulation. As a result, an electrostatic chuck with excellent durability can be provided. In this disclosure, the number, shape, dimensions, etc., of the radially formed resin layer 41 and conductive layer 3 are not limited to those shown in Figure 8, and the design can be appropriately modified according to the actual application. The shapes and dimensions of the resin layers 41 and the conductive layers 3 may be the same or different.

[0083] In the modified example 2, the conductive layer 3 is arranged on the upper surface 1a3 so as to be surrounded by the resin layer 41 (insulating layer 4) (Figure 9(a)). Furthermore, the resin layer 41 is formed concentrically on the upper surface 1a3. This allows for the formation of an even circuit while ensuring insulation, thus achieving both conductivity and insulation. As a result, a highly durable electrostatic chuck can be provided. In this disclosure, when the resin layer 41 is formed concentrically, the number, shape, dimensions, etc., of the resin layer 41 and conductive layer 3 are not limited to those shown in Figure 9, and the design can be appropriately modified according to the actual application.

[0084] [Note] The matters described in each of the above embodiments are noted below.

[0085] (Note 1) A mounting stand 1 comprising: a base 2; a conductive layer 3 provided on at least a part of the outer surface of the base 2; and an insulating layer 4 provided on at least a part of the outer surface of the conductive layer 3, with a mounting surface 1a on which an object to be mounted W is placed, wherein the conductive layer 3 is exposed on the mounting stand 1.

[0086] (Note 2) The mounting base 1 as described in (Note 1), wherein when the mounting base 1 is viewed from a direction perpendicular to the mounting surface 1a, the conductive layer 3 is exposed on the outer circumference of the mounting base 1.

[0087] (Note 3) When the mounting base 1 is viewed from a direction perpendicular to the mounting surface 1a, the exposed conductive layer 3 is spread in an annular shape, as described in (Note 2).

[0088] (Note 4) The mounting base 1 has one or more mounting surfaces 1a (1a1, 1a2, 1a3) at different heights from the bottom surface 2b, which is the surface of the base 2 opposite to the conductive layer 3, and an exposed conductive layer 3 (mounting surface 1a3), and the height from the bottom surface 2b of the base 2 to the exposed upper surface (mounting surface 1a3) of the conductive layer 3 is lower than the height of one or more mounting surfaces 1a (1a1, 1a2) from the bottom surface 2b of the base 2, as described in any of (Note 1) to (Note 3).

[0089] (Note 5) The mounting base 1 as described in (Note 4), wherein on the surface 1a (1a3) of the mounting base 1 in which the conductive layer 3 is exposed, the conductive layer 3 has a recess 3c in which the insulating layer 4 is laminated, and the height from the lower surface 2b of the base 2 to the upper surface 1a (1a3) in which the conductive layer 3 is exposed is at least partially higher than the height from the lower surface 2b of the base 2 to the upper surface of the insulating layer 4 in the recess 3c.

[0090] (Note 6) The mounting base 1 as described in (Note 4), wherein the insulating layer 4 is formed continuously across a plurality of mounting surfaces 1a (1a1, 1a2, 1a3) so as to follow the outer surface of the mounting base 1.

[0091] (Note 7) The insulating layer 4 is a mounting base 1 containing resin, as described in any of (Note 1) to (Note 6).

[0092] (Note 8) The mounting base 1 according to any one of (Note 1) to (Note 6), wherein the insulating layer 4 includes a resin layer 41 and a plasma-resistant layer 42, and the plasma-resistant layer 42 is laminated on the outer surface side of the resin layer 41.

[0093] (Note 9) The mounting platform 1 described in (Note 8) extends from the plasma-resistant layer 42, with the resin layer 41 extending from the plasma-resistant layer 42.

[0094] (Note 10) The mounting stand 1 according to (Note 8) or (Note 9), comprising an intermediate layer 5 between the resin layer 41 and the plasma-resistant layer 42.

[0095] (Note 11) The resin layer 41 contains polyimide, and the mounting base 1 is as described in any of (Note 8) to (Note 10).

[0096] (Note 12) The plasma-resistant layer 42 is a mounting base 1 as described in any of (Note 8) to (Note 11), which includes ceramics.

[0097] (Note 13) An electrostatic chuck equipped with a mounting base 1 as described in any of (Note 1) to (Note 12), wherein an electrode 6 (7) is provided between the mounting surface 1a and the base 2.

Claims

1. A mounting stand comprising: a base; a conductive layer provided on at least a portion of the outer surface of the base; and an insulating layer provided on at least a portion of the outer surface of the conductive layer, having a mounting surface on which an object to be placed is placed, wherein the conductive layer is exposed on the mounting stand.

2. The mounting stand according to claim 1, wherein when the mounting stand is viewed from a direction perpendicular to the mounting surface, the conductive layer is exposed on the outer circumference of the mounting stand.

3. The mounting stand according to claim 2, wherein when the mounting stand is viewed from a direction perpendicular to the mounting surface, the exposed conductive layer extends in an annular shape.

4. The mounting base has one or more mounting surfaces as described above, having different heights from the bottom surface of the base which is the surface opposite to the conductive layer, and an exposed conductive layer, wherein the height from the bottom surface of the base to the exposed top surface of the conductive layer is lower than the height from the bottom surface of the base to the one or more mounting surfaces, according to any one of claims 1 to 3.

5. The mounting base according to claim 4, wherein on the surface of the mounting base described above in which the conductive layer is exposed, the conductive layer has a recess in which the insulating layer is laminated, and the height from the lower surface of the base to the upper surface in which the conductive layer is exposed is at least a portion higher than the height from the lower surface of the base to the upper surface of the insulating layer in the recess.

6. The mounting stand according to claim 4, wherein the insulating layer is formed continuously across the plurality of mounting surfaces so as to be along the outer surface of the mounting stand described above.

7. The mounting stand according to any one of claims 1 to 6, wherein the insulating layer comprises a resin.

8. The mounting stand according to any one of claims 1 to 6, wherein the insulating layer comprises a resin layer and a plasma-resistant layer, and the plasma-resistant layer is laminated on the outer surface side of the resin layer.

9. The mounting platform according to claim 8, wherein the resin layer extends from the plasma-resistant layer.

10. The mounting stand according to claim 8 or 9, further comprising an intermediate layer between the resin layer and the plasma-resistant layer.

11. The mounting platform according to any one of claims 8 to 10, wherein the resin layer comprises polyimide.

12. The mounting platform according to any one of claims 8 to 11, wherein the plasma-resistant layer comprises ceramics.

13. An electrostatic chuck comprising a mounting base according to any one of claims 1 to 12, wherein an electrode is provided between the mounting surface and the base.

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