Electrostatic chuck device

Abstract

An electrostatic chuck device comprises: an electrostatic chuck part that has a dielectric substrate having a placement surface on which a plate-like sample is placed, and an attraction electrode arranged inside the dielectric substrate; and a base that supports the electrostatic chuck part from a rear surface side opposite to the placement surface and can adjust the temperature of the electrostatic chuck part. The electrostatic chuck part protrudes upward from an outer peripheral part of the upper surface of the dielectric substrate, and has an annular protrusion formed in an annular shape when viewed in the thickness direction of the electrostatic chuck part. The base is located at least partially on an inner side in a radial direction with respect to the annular protrusion when viewed in the thickness direction.

Description

Electrostatic Chuck Device

[0001] This application claims priority to Japanese Patent Application No. 2023-106628, filed on June 29, 2023, the contents of which are incorporated herein by reference.

[0002] Electrostatic chuck devices for supporting a substrate such as a semiconductor wafer are known. For example, Patent Document 1 discloses such an electrostatic chuck device having an annular convex portion that contacts the substrate at the outer peripheral edge of a mounting surface on which the substrate (object to be held) is placed, and a through-hole provided inside the annular convex portion while supplying gas between the annular convex portion and the substrate, performing processes such as film formation, etching, and resist film formation on the substrate.

[0003] Japanese Patent Application Laid-Open No. 2006-270084

[0004] In the electrostatic chuck device described above, heat input from processing performed on the upper surface of the substrate causes a temperature rise in the substrate. The inventors have found, through extensive investigation, that the temperature distribution of the substrate during processing tends to increase sharply, particularly at and near the annular convex portion in the radial direction of the substrate, compared to the central portion of the substrate. This steep temperature rise near the annular convex portion can cause distortion of the annular convex portion, potentially leading to gas leakage between the substrate and the annular convex portion. Therefore, it is necessary to suppress distortion of the annular convex portion during substrate processing and suppress gas leakage from between the substrate and the annular convex portion, i.e., prevent gas leakage.

[0005] An object of the present invention is to provide an electrostatic chuck device that can suppress distortion of the annular convex portion during processing of the substrate and suppress gas leakage from between the substrate and the annular convex portion.

[0006] The present invention provides an electrostatic chuck device as described below. It is preferable to combine two or more of the following features as necessary. [1] An electrostatic chuck device comprising: a dielectric substrate having a mounting surface on which a plate-shaped sample is mounted; an electrostatic chuck unit having an attraction electrode disposed inside the dielectric substrate; and a base supporting the electrostatic chuck unit from a back surface opposite the mounting surface and capable of adjusting the temperature of the electrostatic chuck unit, wherein the electrostatic chuck unit has an annular protrusion protruding upward from an outer periphery of an upper surface of the dielectric substrate and having a ring shape as viewed in a thickness direction of the electrostatic chuck unit; the base having a mounting surface on which the electrostatic chuck unit is mounted and a heat conduction suppressing portion provided on the mounting surface, wherein at least a portion of the heat conduction suppressing portion is located radially inward of the annular protrusion as viewed in the thickness direction. [2] An electrostatic chuck device according to [1], wherein a radial width K of the heat conduction suppressing portion is larger than a radial width L of the annular protrusion. [3] The electrostatic chuck device according to [1] or [2], wherein the annular convex portion and a portion of the heat conduction suppressing portion overlap when viewed from the thickness direction. [4] The electrostatic chuck device according to [3], wherein a radial width d of a portion where the annular convex portion and a portion of the heat conduction suppressing portion overlap when viewed from the thickness direction, where L is a radial width of the annular convex portion, satisfies the relationship 0<d<L / 2. [5] The electrostatic chuck device according to any one of [1] to [4], wherein the thermal conductivity of the heat conduction suppressing portion is lower than the thermal conductivity of the base. [6] The electrostatic chuck device according to any one of [1] to [5], wherein a plurality of the heat conduction suppressing portions are provided at intervals between each other in a circumferential direction around a central axis of the electrostatic chuck unit. [7] The electrostatic chuck device according to [6], wherein the heat conduction suppressing portion has an arc-shaped configuration formed concentrically with the annular convex portion. [8] The electrostatic chuck device according to [7], wherein the radius of curvature R2 of the heat conduction suppressing portion is smaller than the radius of curvature R1 of the annular convex portion. [9] The electrostatic chuck device according to [6], wherein the heat conduction suppressing portion has a circular shape with a radius R3 smaller than the radius of curvature R1 of the annular convex portion when viewed in the thickness direction.

[10] The electrostatic chuck device according to any one of [1] to [9], wherein the heat conduction suppressing portion is disposed in a hole or a recess formed in the mounting surface.

[0007] According to the above aspect of the present invention, an electrostatic chuck device is provided that can suppress distortion of the annular convex portion during processing of the substrate and suppress gas leakage from between the substrate and the annular convex portion.

[0008] FIG. 1 is a schematic cross-sectional view showing an example of an electrostatic chuck device according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing an enlarged portion of the electrostatic chuck device of FIG. 1. FIG. 3 is a schematic cross-sectional plan view showing an example of the configuration of a heat conduction suppression unit of an electrostatic chuck device. FIG. 4 is a diagram showing an example of temperature distribution at the outer periphery of a wafer held by an electrostatic chuck device with and without a heat conduction suppression unit. FIG. 5 is a schematic cross-sectional plan view showing an example of the configuration of a heat conduction suppression unit of an electrostatic chuck device according to a second embodiment. FIG. 6 is a schematic cross-sectional plan view showing an example of the configuration of a heat conduction suppression unit of an electrostatic chuck device according to a third embodiment. FIG. 7 is a schematic cross-sectional plan view showing an example of the configuration of a heat conduction suppression unit of an electrostatic chuck device according to a fourth embodiment. FIG. 8 is a schematic explanatory view showing an example of a semiconductor manufacturing apparatus having the above-described electrostatic chuck device.

[0009] Preferred examples of each embodiment of the electrostatic chuck device of the present invention will be described below with reference to the drawings. Note that in all of the following drawings, the dimensions and ratios of each component may be displayed differently as appropriate to make the drawings easier to understand. Furthermore, these embodiments are specifically described to better understand the gist of the invention, and unless otherwise specified, do not limit the present invention. For example, unless otherwise specified, conditions such as materials, amounts, types, numbers, sizes, shapes, positions, ratios, and temperatures may be changed, added, or omitted as necessary. The first to fourth embodiments described below may share preferred features and conditions with each other, provided that no problems arise.

[0010] First Embodiment (Entire Electrostatic Chuck Device) FIG. 1 is a schematic cross-sectional view showing an example of an electrostatic chuck device according to this embodiment. The electrostatic chuck device 100 shown in FIG. 1 is disposed in a vacuum chamber of a plasma processing apparatus, for example, with a mounting surface 11 a on which a wafer (plate-shaped sample) W is placed facing upward. Each drawing shows a Z-axis to explain the reference of the electrostatic chuck device. The Z-axis direction is, for example, the vertical direction. The central axis O of the mounting surface 11 a is parallel to the Z-axis. The arrangement of the electrostatic chuck device 100 in the vertical direction is merely an example, and other arrangements may be used.

[0011] The electrostatic chuck device 100 includes an electrostatic chuck unit 10 that attracts and supports a plate-shaped sample such as a wafer W, a base 20 that supports the electrostatic chuck unit 10, and a heat conduction suppressing unit 50A.

[0012] (Electrostatic Chuck Portion) The electrostatic chuck portion 10 includes a dielectric substrate 11 and an attraction electrode 30 .

[0013] (Dielectric Substrate) The dielectric substrate 11 is a plate-like member that is circular or approximately circular in plan view. In this specification, the thickness direction of the dielectric substrate 11 may be simply referred to as the "thickness direction." In this specification, the electrostatic chuck device will be described with the side in the thickness direction on which the wafer W is mounted being referred to as the "upper side" and the opposite side being referred to as the "lower side." In this specification, the "upper side" and the "lower side" indicate examples of the orientation of the electrostatic chuck device when in use, and do not limit the orientation of the electrostatic chuck device when in use.

[0014] The dielectric substrate 11 is preferably made of a composite sintered body that has mechanical strength and durability against corrosive gases and their plasma. Ceramics that have mechanical strength and durability against corrosive gases and their plasma are preferably used as the dielectric material that constitutes the dielectric substrate 11. Suitable ceramics that constitute the dielectric substrate 11 include, for example, aluminum oxide sintered body, aluminum nitride sintered body, and aluminum oxide-silicon carbide composite sintered body.

[0015] A mounting surface 11a on which a wafer W is placed is configured on the upper surface of the dielectric substrate 11. That is, the mounting surface 11a on which the wafer W is placed is provided on the dielectric substrate 11. In this embodiment, a plurality of protrusions 12 protruding upward are formed at predetermined intervals on the upper surface of the dielectric substrate 11.

[0016] FIG. 2 is an enlarged cross-sectional view of a portion of the electrostatic chuck device of FIG. 1 . As shown in FIGS. 1 and 2 , among the multiple protrusions 12, the protrusions 12 located on the outer periphery of the dielectric substrate 11 are annular convex portions 12C formed in a ring shape when viewed in the thickness direction. The annular convex portion preferably has a continuous shape, and its upper surface is preferably flat. The term "annular" may refer to a circular ring or a substantially circular ring. The annular protrusions 12C and the dielectric substrate 11 are preferably integrally formed, and the annular protrusions 12C and the dielectric substrate 11 are preferably formed from the same material, although examples are not limited to these. As shown in FIG. 2 , the annular protrusions 12C have a width L of, for example, 0.5 mm to 5 mm in the radial direction of the dielectric substrate 11, which may be selected arbitrarily. The width L may be 0.8 mm to 3.5 mm, 1.5 mm to 2.5 mm, or the like.

[0017] The tip surfaces of the multiple protrusions 12, including the annular protrusion 12C, form the mounting surface 11a. The tip surface (mounting surface 11a) of the annular protrusion 12C continuously contacts the underside of the wafer W all around the circumference of the wafer W. It is preferable that the heights of the annular protrusion 12C and the protrusions 12 are the same or approximately the same. In the dielectric substrate 11, recesses (valleys) 13 recessed downward from the mounting surface 11a are formed between adjacent multiple protrusions 12. The bottom surfaces 13b of the recesses 13 face upward (toward the wafer W).

[0018] The dielectric substrate 11 is preferably provided with a gas hole (not shown). The gas hole penetrates the dielectric substrate 11 in the thickness direction. The gas hole is provided radially inward relative to the annular protrusion 12C. The gas hole is connected to a gas supply device (not shown). The gas hole supplies an arbitrarily selected cooling gas, such as helium (He), to the space between the wafer W placed on the mounting surface 11a and the bottom surface 13b of the recess 13. The supplied cooling gas cools the wafer W placed on the mounting surface 11a. The tip surface of the annular protrusion 12C is in continuous contact with the entire circumference of the underside of the wafer W, thereby preventing the cooling gas from leaking radially outward from the annular protrusion 12C.

[0019] (Adsorption Electrode) The adsorption electrode 30 is embedded in the dielectric substrate 11. The adsorption electrode 30 is conductive. The adsorption electrode 30 is located inside the dielectric substrate 11. The adsorption electrode 30 extends, for example, in a layer shape along a plane perpendicular to the thickness direction of the dielectric substrate 11. The adsorption electrode 30 is disposed in the dielectric substrate 11 below the mounting surface 11a and the bottom surface 13b, at a predetermined distance therefrom.

[0020] The chucking electrode 30 is connected to a DC power supply (not shown) via a power supply (not shown). The chucking electrode 30 generates an electrostatic chucking force by a DC current supplied from the DC power supply, thereby attracting the wafer W to the mounting surface 11a. The chucking electrode 30 may have any shape and any number. For example, the chucking electrode 30 is not limited to a monopolar chucking electrode, but may be a bipolar chucking electrode consisting of two electrodes having a semicircular shape in a plan view. The chucking electrode 30 may be provided only on a portion of the circumference of the electrostatic chuck unit 10 when viewed in the thickness direction. A plurality of chucking electrodes 30 may be provided at intervals around the circumference of the electrostatic chuck unit 10 when viewed in the thickness direction.

[0021] The chucking electrode 30 can be made of any material, and is made of, for example, a composite of an insulating material and a conductive material. The insulating material contained in this composite is not particularly limited, but may be, for example, aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), silicon nitride (Si ３ N ４), yttrium (III) oxide (Y ２ O ３ ), yttrium aluminum garnet (YAG) and SmAlO ３ The conductive material contained in the composite material is preferably at least one selected from the group consisting of molybdenum carbide (Mo ２ It is preferable that the material is at least one selected from the group consisting of molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0022] Such an attraction electrode 30 may be formed in a predetermined shape in advance, or may be formed by three-dimensional printing, vapor deposition, etc. The attraction electrode 30 may be embedded in the dielectric substrate 11 by laminating the dielectric substrate 11 in multiple steps.

[0023] (Base) In this embodiment, the base 20 is made of a thick, disk-shaped metal member. The base 20 supports the electrostatic chuck unit 10 from below (the side opposite the mounting surface 11a). The material constituting the base 20 can be selected arbitrarily. For example, any metal with excellent thermal conductivity, electrical conductivity, and workability, or a composite material containing such a metal, can be used without particular limitation. For example, aluminum, aluminum alloy, copper, copper alloy, stainless steel, etc. are preferably used. The characteristics and configuration of the base for adjusting the temperature of the electrostatic chuck unit can be selected arbitrarily. For example, the temperature of the electrostatic chuck unit can be effectively adjusted by using a heat conduction suppressing portion described below or a flow path described below. Furthermore, the base 20 in this embodiment preferably has a flow path 21 within its disk-shaped structure for circulating a liquid coolant such as water, and in this embodiment, it is water-cooled. The coolant circulated through the flow path 21 can be selected arbitrarily, and can be He gas, N ２ The base 20 can cool the electrostatic chuck unit 10 by the coolant circulated through the flow path 21, thereby adjusting the temperature of the electrostatic chuck unit 10.

[0024] The base 20 has a mounting surface 20t facing upward. The mounting surface 20t of the base 20 is adhered to the lower surface 11b of the dielectric substrate 11 via an adhesive layer 25. The material forming the adhesive layer 25 can be selected arbitrarily, and may be, for example, a heat-resistant resin such as polyimide resin, silicone resin, or epoxy resin, or an insulating sheet- or film-shaped adhesive resin.

[0025] (Heat Conduction Suppression Part) In this embodiment, the heat conduction suppression part 50A is embedded in the base 20. In this embodiment, the heat conduction suppression part 50A is preferably disposed in a recess 22 formed in the mounting surface 20t of the base 20. The recess 22 is filled with a selected material or is left as an empty space. The heat conduction suppression part 50A is provided on the mounting surface 20t. In this embodiment, the upper surface 50a of the heat conduction suppression part 50A is formed at the same height as the mounting surface 20t of the base 20. The heat conduction suppression part 50A may be disposed in a hole (a bottomed hole or a through-hole) formed in the base 20. For example, the heat conduction suppression part 50A may be provided in the hole. The recess 22 or hole in which the heat conduction suppression part 50A is provided may also serve a purpose other than providing the heat conduction suppression part 50A, as necessary. The bottom surface of the recess 22 may be flat, but is not limited to this example. The material forming the heat conduction suppression part 50A is preferably different from the material forming the base 20. Specific examples of materials for forming the heat conduction suppressing portion 50A include, but are not limited to, alumina, yttria, and aluminum nitride.

[0026] FIG. 3 is a plan cross-sectional view showing the configuration of the heat conduction suppression portion of the electrostatic chuck device. As shown in FIG. 3 , in this embodiment, the heat conduction suppression portion 50A is annular when viewed in the thickness direction. When viewed in the thickness direction, at least a portion of the heat conduction suppression portion 50A is located radially inward of the annular protrusion 12C. As shown in FIGS. 2 and 3 , in this embodiment, the outer peripheral edge 50s of the heat conduction suppression portion 50A is located between the inner peripheral edge 12s and the outer peripheral edge 12t of the annular protrusion 12C when viewed in the thickness direction. In this embodiment, the inner peripheral edge 50t of the heat conduction suppression portion 50A is located radially inward of the inner peripheral edge 12s of the annular protrusion 12C when viewed in the thickness direction. As a result, in this embodiment, a radial portion of the heat conduction suppression portion 50A overlaps with the annular protrusion 12C when viewed in the thickness direction.

[0027] The outer peripheral edge 50s of the heat conduction suppression portion 50A may be located radially inward of the inner peripheral edge 12s of the annular protrusion 12C when viewed from the thickness direction. That is, when viewed from the thickness direction, the heat conduction suppression portion 50A may not overlap the annular protrusion 12C, and a radial gap may be formed between the outer peripheral edge 50s of the heat conduction suppression portion 50A and the inner peripheral edge 12s of the annular protrusion 12C. In such a case, the distance between the heat conduction suppression portion 50A and the inner peripheral edge 12s of the annular protrusion 12C can be selected arbitrarily. For example, the distance may be 0 to 0.5 times, 0.01 to 0.7 times, 0.05 to 0.8 times, or 0.1 to 1.0 times the radial width of the annular protrusion 12C, but is not limited to these examples.

[0028] As shown in FIG. 2 , in this embodiment, the radial width K of the heat conduction suppression portion 50A is preferably greater than the radial width L of the annular protrusion 12C to effectively moderate the temperature gradient of the annular protrusion 12C, and is preferably smaller than the thickness of the cooling base 20 to avoid excessive suppression of the wafer cooling effect. The radial width K of the heat conduction suppression portion 50A can be selected arbitrarily, but is preferably set to, for example, 0.5 mm to 30 mm. The width K may be set to, for example, 1.5 mm to 25 mm, 3.0 mm to 20 mm, or 7.0 mm to 15 mm. The depth (thickness) of the heat conduction suppression portion 50A can be selected arbitrarily, and may be, for example, 0.1 to 1.0 mm, 0.5 to 3.0 mm, or 1.0 to 10.0 mm, but is not limited to these examples. Note that in this embodiment, the width K is constant; however, if the width is not constant, it may refer to the value at the position where the radial width is greatest.

[0029] Furthermore, when viewed in the thickness direction, the radial width d of the portion where the annular protrusion 12C and a part of the heat conduction suppressing portion 50A overlap is preferably set so that the relationship 0 < d < L / 2 is satisfied, where L is the radial width of the annular protrusion 12C. Setting it in this manner is even more preferable, as it makes it possible to prevent the temperature gradient of the annular protrusion 12C from becoming steep while cooling the outermost periphery of the wafer, which is prone to high temperatures.

[0030] The thermal conductivity of the heat conduction suppression portion 50A is preferably lower than that of the base 20. The heat conduction suppression portion 50A is preferably formed from a material having a lower thermal conductivity than the material forming the base 20, such as a metal or a composite material containing a metal. Examples of materials forming the heat conduction suppression portion 50A include Teflon (registered trademark), plastic materials, organic and inorganic adhesives, highly insulating insulators, and ceramic materials. More specific preferred examples include alumina, yttria, and aluminum nitride. The heat conduction suppression portion 50A may be, for example, a space. The thermal conductivity of the material forming the heat conduction suppression unit 50A may be, for example, 0.1 to 10 W / (m·K), 0.5 to 20 W / (m·K), 1.0 to 30 W / (m·K), 5 to 50 W / (m·K), 10 to 100 W / (m·K), 100 to 150 W / (m·K), or 150 to 200 W / (m·K), but is not limited to these examples. The ratio of the thermal conductivity of the heat conduction suppression unit 50A to the thermal conductivity of the base 20 (thermal conductivity of the heat conduction suppression unit 50A / thermal conductivity of the base 20) can be selected arbitrarily and may be, for example, 0.01 to 0.1 times, 0.05 to 0.5 times, or 0.1 to 0.9 times, but is not limited to these examples.

[0031] 4 shows an example of the temperature distribution at the outer periphery of a wafer held by an electrostatic chuck device with and without a heat conduction suppression unit. Here, the temperature distribution at and near the annular protrusion 12C on the outer periphery of the electrostatic chuck unit 10 when performing plasma processing on a wafer W held by the electrostatic chuck unit 10 is compared between a case where the heat conduction suppression unit 50A is provided and a case where the heat conduction suppression unit 50A is not provided. As shown in FIG. 4 , when the heat conduction suppression unit 50A is not provided, the temperature of the wafer W increases sharply toward the outer periphery of the wafer W in contact with the annular protrusion 12C compared to the central portion of the wafer W. In contrast, when the heat conduction suppression unit 50A is provided on the mounting surface 20t of the base 20 as in the above embodiment, the temperature of the wafer W increases at the outer periphery of the wafer W in contact with the annular protrusion 12C compared to the central portion of the wafer W, but the temperature gradient, i.e., the temperature increase, is gentler toward the outer periphery of the wafer W. This is because the heat conduction suppression portion 50A suppresses the conduction of the heat (cold heat) that cools the electrostatic chuck portion 10, which is provided by the refrigerant circulating through the flow path 21 of the base 20, to the annular convex portion 12C of the electrostatic chuck portion 10 and its vicinity.

[0032] In this way, the provision of the heat conduction suppressing portion 50A suppresses heat conduction from the base 20 to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity. As a result, temperature changes become gentler, and distortion that occurs in the annular protrusion 12C when performing plasma processing on the wafer W can be alleviated. These effects prevent cooling gas such as helium (He) from leaking to the outside from between the wafer W and the annular protrusion 12C due to distortion of the annular protrusion 12C.

[0033] The electrostatic chuck device 100 of this embodiment includes a heat conduction suppressing portion 50A, at least a portion of which is located radially inward of the annular protrusion 12C when viewed in the thickness direction. This configuration can suppress heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity. This can alleviate distortion that occurs in the annular protrusion 12C when performing plasma processing on the wafer W. As a result, leakage of cooling gas such as helium (He) to the outside from between the wafer W and the annular protrusion 12C can be suppressed.

[0034] In the electrostatic chuck unit 10 of this embodiment, the radial width K of the heat conduction suppressing portion 50A is preferably larger than the radial width L of the annular protrusion 12C. This configuration more effectively suppresses heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity. Furthermore, by reducing the radial width L of the annular protrusion 12C compared to the radial width K of the heat conduction suppressing portion 50A, the product yield of wafers W can be increased. The radial width K of the heat conduction suppressing portion 50A may be 1.0 to 10 times, more preferably 1.5 to 9 times, even more preferably 2 to 8 times, and particularly preferably 4 to 7 times the radial width L of the annular protrusion 12C, but is not limited to these examples. It may also be 1.1 to 1.5 times, 1.3 to 1.8 times, or the like.

[0035] In the electrostatic chuck unit 10 of this embodiment, it is preferable that the annular protrusion 12C and a portion of the heat conduction suppressing unit 50A overlap when viewed in the thickness direction. This configuration suppresses heat conduction from a gap between the annular protrusion 12C and the heat conduction suppressing unit 50A. This effectively suppresses heat conduction to the vicinity of the annular protrusion 12C of the electrostatic chuck unit 10.

[0036] In the electrostatic chuck unit 10 of this embodiment, the radial width d of the portion where the annular protrusion 12C overlaps with a portion of the heat conduction suppressing unit 50A preferably satisfies the relationship 0 < d < L / 2, relative to the radial width L of the annular protrusion 12C. Alternatively, the relationship 0 < d < L / 3, 0 < d < L / 4, or 0 < d < L / 6 may be satisfied. With this configuration, heat conduction to the vicinity of the annular protrusion 12C of the electrostatic chuck unit 10 can be effectively suppressed while keeping the width d of the portion where the annular protrusion 12C overlaps with a portion of the heat conduction suppressing unit 50A small. The value d is selected as needed, and may be, for example, 0.01 mm to 5.0 mm, 0.05 mm to 2.5 mm, 0.1 mm to 2.0 mm, 0.3 mm to 1.5 mm, or 0.5 mm to 1.0 mm, but is not limited to these examples. Note that, although the width d is constant in this embodiment, if the width is not constant, it may refer to the value at the position where the radial width is greatest.

[0037] In the electrostatic chuck unit 10 of this embodiment, the thermal conductivity of the heat conduction suppressing portion 50A is lower than the thermal conductivity of the base 20. According to this configuration, heat conduction to the vicinity of the annular convex portion 12C of the electrostatic chuck unit 10 can be efficiently suppressed.

[0038] In the electrostatic chuck unit 10 of this embodiment, the heat conduction suppressing unit 50A is disposed in a recess 22 or a hole formed in the mounting surface 20t of the base 20. According to this configuration, the heat conduction suppressing unit 50A can be easily provided while being integrated with the base 20.

[0039] Second Embodiment Next, an electrostatic chuck device according to a second embodiment of the present invention will be described. The electrostatic chuck device 100 of this embodiment differs from the electrostatic chuck device 100 of the first embodiment in the configuration of a heat conduction suppression unit 50B, but the other configuration is common to the electrostatic chuck device 100. Therefore, the following mainly describes the heat conduction suppression unit 50B, and a description of the configuration common to the electrostatic chuck device 100 will be omitted.

[0040] 5 is a plan cross-sectional view showing the configuration of a heat conduction suppressing unit in an electrostatic chuck device according to the second embodiment. The electrostatic chuck device 100 includes an electrostatic chuck unit 10 and a base 20 (not shown). A heat conduction suppressing unit 50B is provided on a mounting surface 20t of the base 20 (not shown).

[0041] In this embodiment, the thermal conduction suppressing portions 50B are provided at equal intervals in the circumferential direction around the central axis of the electrostatic chuck unit 10, as viewed from the thickness direction. Each of the thermal conduction suppressing portions 50B has an arc-like shape formed concentrically with the annular protrusion 12C. As viewed from the thickness direction, at least a portion of each thermal conduction suppressing portion 50B is located radially inward of the annular protrusion 12C. In this embodiment, as viewed from the thickness direction, a radial portion of each thermal conduction suppressing portion 50B overlaps with the annular protrusion 12C. As viewed from the thickness direction, each thermal conduction suppressing portion 50B preferably has a constant or approximately constant width, e.g., a radial width, as viewed from the thickness direction. Each thermal conduction suppressing portion 50B is formed solely of curved surfaces without any corners as viewed from the thickness direction. However, if necessary, it may have corners, such as a fan-like shape. The number of thermal conduction suppressing portions 50B can be selected arbitrarily and may be an even or odd number. Examples include, but are not limited to, 2 to 200, 3 to 100, 4 to 50, 6 to 30, 8 to 15, and 10 to 12. The shapes and sizes of the heat conduction suppressing portions 50B are preferably all the same or approximately the same when viewed in the thickness direction, but may vary as necessary. For example, two or more of the shapes of the heat conduction suppressing portions of the second to fourth embodiments may be selected and arranged in combination. Examples include a combination of the heat conduction suppressing portions of the second and third embodiments, a combination of the heat conduction suppressing portions of the third and fourth embodiments, and a combination of the heat conduction suppressing portions of the second and fourth embodiments. It is preferable that the heat conduction suppressing portions 50B be arranged in a balanced and regular pattern. For example, heat conduction suppressing portions 50B of different shapes may be arranged alternately with gaps between them in the circumferential direction.

[0042] The electrostatic chuck device 100 of this embodiment includes a heat conduction suppressing portion 50B, at least a portion of which is located radially inward of the annular protrusion 12C when viewed in the thickness direction. This configuration can suppress heat conduction to the vicinity of the annular protrusion 12C of the electrostatic chuck unit 10. This can alleviate distortion that occurs in the annular protrusion 12C when performing plasma processing on the wafer W. As a result, leakage of cooling gas such as helium (He) to the outside from between the wafer W and the annular protrusion 12C can be suppressed.

[0043] In the electrostatic chuck device 100 of this embodiment, a plurality of heat conduction suppressing portions 50B are provided at intervals between each other in the circumferential direction around the central axis of the electrostatic chuck unit 10. This reduces the suppression of heat conduction between adjacent heat conduction suppressing portions 50B in the circumferential direction. Therefore, the heat conduction suppressing portions 50B can reduce the area of ​​the region where heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity is suppressed, i.e., the area can be reduced. Here, by suppressing heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity using the heat conduction suppressing portions 50B, distortion occurring in the annular protrusion 12C is alleviated. However, the electrostatic chuck unit 10 near the annular protrusion 12C may not be sufficiently cooled, which may adversely affect plasma processing of the wafer W. In contrast, in this embodiment, by providing the heat conduction suppressing portions 50B at intervals in the circumferential direction, it is possible to reduce the area in the vicinity of the annular convex portion 12C where the electrostatic chuck portion 10 is not sufficiently cooled. As a result, it is possible to reduce the area in which the plasma processing of the wafer W is adversely affected, and to increase the product yield.

[0044] In the electrostatic chuck device 100 of this embodiment, the heat conduction suppressing portion 50B has an arc shape that is formed concentrically with the annular protrusion 12C, which makes it easy to form the heat conduction suppressing portion 50B.

[0045] Third Embodiment Next, an electrostatic chuck device according to a third embodiment of the present invention will be described. The electrostatic chuck device 100 of this embodiment differs from the electrostatic chuck devices 100 of the first and second embodiments in the configuration of a heat conduction suppression unit 50C, but the other configuration is common to the electrostatic chuck device 100. Therefore, the following mainly describes the heat conduction suppression unit 50C, and a description of the configuration common to the electrostatic chuck device 100 will be omitted.

[0046] 6 is a plan cross-sectional view showing the configuration of a heat conduction suppressing unit in an electrostatic chuck device according to a third embodiment. The electrostatic chuck device 100 includes an electrostatic chuck unit 10 and a base 20 (not shown). A heat conduction suppressing unit 50C is provided on a mounting surface 20t of the base 20 (not shown).

[0047] In the present embodiment, a plurality of heat conduction suppressing portions 50C are provided at intervals in the circumferential direction around the central axis of the electrostatic chuck unit 10, as viewed in the thickness direction. Each of the plurality of heat conduction suppressing portions 50C has an arc shape in which the radius of curvature R2 of the heat conduction suppressing portion 50C is smaller than the radius of curvature R1 of the annular protrusion 12C. As viewed in the thickness direction, the center portion 50r of each heat conduction suppressing portion 50C overlaps with the annular protrusion 12C. As viewed in the thickness direction, both end portions 50p, 50q of each heat conduction suppressing portion 50C are located radially inward of the annular protrusion 12C.

[0048] The electrostatic chuck device 100 of this embodiment includes a heat conduction suppressing portion 50C, at least a portion of which is located radially inward of the annular protrusion 12C when viewed in the thickness direction. This configuration can suppress heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity. This can alleviate distortion that occurs in the annular protrusion 12C when performing plasma processing on the wafer W. As a result, leakage of cooling gas such as helium (He) to the outside from between the wafer W and the annular protrusion 12C can be suppressed.

[0049] In the electrostatic chuck device 100 of this embodiment, a plurality of heat conduction suppressing portions 50C are provided at intervals between each other in the circumferential direction around the central axis of the electrostatic chuck unit 10. This makes it possible to reduce the area of ​​the region where heat conduction to the annular protrusion 12C of the electrostatic chuck unit 10 and its vicinity is suppressed by the heat conduction suppressing portions 50C, i.e., to reduce the area. Therefore, similar to the second embodiment, it is possible to reduce the region in the annular protrusion 12C and its vicinity where sufficient cooling of the electrostatic chuck unit 10 is not possible. As a result, it is possible to reduce the region that adversely affects plasma processing of the wafer W, thereby increasing the product yield.

[0050] In the electrostatic chuck device 100 of this embodiment, the heat conduction suppressing portion 50C has an arc-shaped curvature radius R2 that is smaller than the curvature radius R1 of the annular protrusion 12C. As a result, the two end portions 50p and 50q of each heat conduction suppressing portion 50C are located radially inward of the central portion 50r of the annular protrusion 12C. The heat conduction suppressing effect and position of each heat conduction suppressing portion 50C gradually change from the central portion 50r to the two end portions 50p and 50q. This prevents a sudden change in the heat conduction suppressing effect near the boundary between the portion where the heat conduction suppressing portion 50C is provided and the portion where the heat conduction suppressing portion 50C is not provided. Therefore, distortion of the annular protrusion 12C can be effectively suppressed. The ratio of the radius of curvature R2 of the heat conduction suppression portion 50C to the radius of curvature R1 of the annular convex portion 12C can be selected arbitrarily, and for example, the ratio (R2 / R1) can be 1 / 1 to 1 / 1.5, 1 / 1.5 to 1 / 5, 1 / 5 to 1 / 10, or 1 / 10 to 1 / 20, but is not limited to these examples.

[0051] Fourth Embodiment Next, an electrostatic chuck device according to a fourth embodiment of the present invention will be described. The electrostatic chuck device 100 of this embodiment differs from the electrostatic chuck devices 100 of the first to third embodiments in the configuration of a heat conduction suppression unit 50D, but the other configuration is common to the electrostatic chuck device 100. Therefore, the following mainly describes the heat conduction suppression unit 50D, and a description of the configuration common to the electrostatic chuck device 100 will be omitted.

[0052] 7 is a plan cross-sectional view showing the configuration of a heat conduction suppressing unit in an electrostatic chuck device according to a fourth embodiment. The electrostatic chuck device 100 includes an electrostatic chuck unit 10 and a base 20 (not shown). A heat conduction suppressing unit 50D is provided on a mounting surface 20t of the base 20 (not shown).

[0053] In the present embodiment, a plurality of heat conduction suppressing portions 50D are provided at intervals in the circumferential direction around the central axis of the electrostatic chuck unit 10, as viewed in the thickness direction. Each of the plurality of heat conduction suppressing portions 50D has a circular shape, as viewed in the thickness direction, with a radius R3 that is smaller than the radius of curvature R1 of the annular protrusion 12C. As viewed in the thickness direction, a portion of each heat conduction suppressing portion 50D overlaps with the annular protrusion 12C, and the remaining portion is located radially inward of the annular protrusion 12C.

[0054] The electrostatic chuck device 100 of this embodiment includes a heat conduction suppressing portion 50D, at least a portion of which is located radially inward of the annular protrusion 12C when viewed in the thickness direction. This configuration can suppress heat conduction to the vicinity of the annular protrusion 12C of the electrostatic chuck unit 10. This can alleviate distortion that occurs in the annular protrusion 12C when performing plasma processing on the wafer W. As a result, leakage of cooling gas such as helium (He) to the outside from between the wafer W and the annular protrusion 12C can be suppressed.

[0055] In the electrostatic chuck device 100 of this embodiment, a plurality of heat conduction suppressing portions 50D are provided at intervals in the circumferential direction around the central axis of the electrostatic chuck unit 10. This makes it possible to reduce the area of ​​the region where heat conduction to the vicinity of the annular protrusion 12C of the electrostatic chuck unit 10 is suppressed by the heat conduction suppressing portions 50D. Therefore, similar to the second and third embodiments, it is possible to reduce the region near the annular protrusion 12C where sufficient cooling of the electrostatic chuck unit 10 is not possible. As a result, it is possible to reduce the region that is adversely affected by plasma processing of the wafer W, thereby increasing the product yield.

[0056] In the electrostatic chuck device 100 of this embodiment, the heat conduction suppressing portions 50D are circular in shape with a radius R3 smaller than the radius of curvature R1 of the annular convex portion 12C when viewed in the thickness direction. As a result, the heat conduction suppressing effect of each heat conduction suppressing portion 50D gradually changes from the portion overlapping the annular convex portion 12C when viewed in the thickness direction toward both sides of the annular convex portion 12C in the circumferential direction. This prevents a sudden change in the heat conduction suppressing effect near the boundary between the portion where the heat conduction suppressing portion 50D is provided and the portion where the heat conduction suppressing portion 50D is not provided. Therefore, distortion of the annular convex portion 12C can be suppressed. The ratio of the radius of the heat conduction suppressing portion 50D to the diameter of the electrostatic chuck portion (radius of the heat conduction suppressing portion 50D / radius of the electrostatic chuck portion) can be arbitrarily selected, and examples include, but are not limited to, 1 / 1.5 to 1 / 5, 1 / 5 to 1 / 10, and 1 / 10 to 1 / 20.

[0057] 8 is a schematic diagram showing an example of a semiconductor manufacturing apparatus having the electrostatic chuck device described above. The semiconductor manufacturing apparatus 1000 includes the electrostatic chuck device 100, a vacuum chamber 200, an upper electrode 300, a magnet 400, a gas supply means 500, a vacuum pump 600, and a vacuum stabilization system 700.

[0058] The vacuum chamber 200 accommodates the electrostatic chuck device 100 and is used as a reaction field for performing plasma processing therein. A known configuration used in semiconductor manufacturing equipment can be adopted for the vacuum chamber 200. The vacuum chamber 200 has a gate (not shown) for loading and unloading a plate-shaped sample.

[0059] The upper electrode 300 is accommodated in the vacuum chamber 200 and is a counter electrode used in cooperation with the electrostatic chuck device 100 when generating plasma in the vacuum chamber 200. The upper electrode 300 is connected to a power supply (not shown).

[0060] The magnets 400 are arranged around the vacuum chamber 200 and generate a vertical magnetic field in the space between the upper electrode 300 and the electrostatic chuck device 100 within the vacuum chamber 200 .

[0061] The gas supply means 500 supplies the plasma gas G into the vacuum chamber 200. The gas supply means 500 supplies the plasma gas G into the vacuum chamber 200 from gas holes provided in the upper electrode 300, for example.

[0062] The vacuum pump 600 exhausts gas from the vacuum chamber 200 and prepares an atmosphere for generating plasma. The vacuum pump 600 is connected to the vacuum chamber 200, for example, at a position lower than the electrostatic chuck device 100.

[0063] The vacuum stabilization system 700 stabilizes the vacuum in the vacuum chamber 200. The vacuum stabilization system 700 includes a detector 710 and a control unit 720 that controls the semiconductor manufacturing apparatus 1000 based on the detection results of the detector 710.

[0064] The detector 710 detects the degree of vacuum inside the vacuum chamber 200. The number of detectors 710 may be one or more.

[0065] Control unit 720 controls semiconductor manufacturing equipment 1000 based on the detected value of the degree of vacuum in vacuum chamber 200 detected by detector 710. Control unit 720 pre-stores a correspondence between the detected values ​​of the above items, the supply amount of plasma gas G supplied into vacuum chamber 200 by gas supply means 500, and the operation of vacuum pump 600. Based on the detected value and the correspondence, control unit 720 feedback-controls semiconductor manufacturing equipment 1000 so that the degree of vacuum in vacuum chamber 200 falls within a predetermined range. In this way, vacuum stabilization system 700 suppresses fluctuations in the degree of vacuum in vacuum chamber 200 in semiconductor manufacturing equipment 1000 and stabilizes the state.

[0066] The control unit 720 may be a component specific to the vacuum stabilization system 700, or the control device that controls the semiconductor manufacturing apparatus 1000 may also have this function.

[0067] According to the semiconductor manufacturing apparatus 1000 of this embodiment, since the semiconductor manufacturing apparatus 1000 includes the electrostatic chuck device 100 described above, leakage of the cooling gas into the vacuum chamber 200 from between the wafer W and the annular protrusion 12C can be suppressed.

[0068] Furthermore, in the semiconductor manufacturing apparatus 1000, the electrostatic chuck device 100 prevents the cooling gas from leaking into the vacuum chamber 200 from between the wafer W and the annular convex portion 12C, and the vacuum stabilization system 700 can suppress fluctuations in the vacuum degree within the vacuum chamber 200. This enables stable plasma processing, resulting in a semiconductor manufacturing apparatus with improved yield.

[0069] The above describes the embodiments and their modifications of the present invention. However, the configurations and combinations thereof in the embodiments and modifications are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments. For example, in the above embodiment, plasma processing is performed on the wafer W. However, the processing and apparatus for the wafer W may be other processing and apparatuses other than plasma processing. Furthermore, in the above embodiment, a member with a lower thermal conductivity than the base is disposed on the mounting surface of the base as the heat conduction suppressing portion. However, for example, a recess may be formed in a portion of the mounting surface of the base, and the internal space may be used as the heat conduction suppressing portion without filling the recess with a member, thereby reducing the contact area with the adhesive layer 25 and thereby reducing heat transfer to the electrostatic chuck portion.

[0070] DESCRIPTION OF SYMBOLS 10...Electrostatic chuck portion 11...Dielectric substrate 11a...Mounting surface 11b...Lower surface 12...Protrusion 12C...Annular convex portion 12s...Inner peripheral edge of annular convex portion 12t...Outer peripheral edge of annular convex portion 13...Recess 13b...Bottom surface 20...Base 20t...Mounting surface 21...Flow path 22...Recess 25...Adhesive layer 30...Clutch electrode 50a...Upper surface 50A to 50D...Heat conduction suppression portion 50p, 50q...Both ends 50r...Central portion of heat conduction suppression portion 50s...Outer peripheral edge of heat conduction suppression portion 50t...Inner peripheral edge of heat conduction suppression portion 100...Electrostatic chuck device 200...Vacuum chamber 300...Upper electrode 400...Magnet 500...Gas supply means 600...Vacuum pump 700...Vacuum degree stabilization system 710...Detector 720...Control unit 1000 Semiconductor manufacturing equipment d...width G...plasma gas K, L...width O...center axis R1, R2...radius of curvature R3...radius W...wafer (plate-shaped sample)

Claims

1. An electrostatic chuck device comprising: a dielectric substrate having a mounting surface on which a plate-shaped sample is placed; an electrostatic chuck unit having an adsorption electrode arranged inside the dielectric substrate; and a base supporting the electrostatic chuck unit from a back surface side opposite the mounting surface and capable of adjusting the temperature of the electrostatic chuck unit, wherein the electrostatic chuck unit has an annular protrusion that protrudes upward from the outer periphery of an upper surface of the dielectric substrate and is formed in a ring shape when viewed in a thickness direction of the electrostatic chuck unit, the base having a mounting surface on which the electrostatic chuck unit is mounted; and a heat conduction suppression unit provided on the mounting surface, wherein at least a portion of the heat conduction suppression unit is located radially inward from the annular protrusion when viewed in the thickness direction.

2. The electrostatic chuck device according to claim 1, wherein the radial width K of the heat conduction suppressing portion is larger than the radial width L of the annular convex portion.

3. The electrostatic chuck device according to claim 1, wherein the annular protrusion and a portion of the heat conduction suppressing portion overlap when viewed in the thickness direction.

4. An electrostatic chuck device as described in claim 3, wherein the radial width d of the portion where the annular convex portion and a part of the heat conduction suppressing portion overlap when viewed in the thickness direction satisfies 0 < d < L / 2, where L is the radial width of the annular convex portion.

5. An electrostatic chuck device as set forth in claim 1, wherein the thermal conductivity of the heat conduction suppressing portion is lower than the thermal conductivity of the base.

6. An electrostatic chuck device according to claim 1, wherein the heat conduction suppression portion is provided in a plurality of portions spaced apart from each other in a circumferential direction around a central axis of the electrostatic chuck portion.

7. An electrostatic chuck device according to claim 6, wherein the heat conduction suppressing portion has an arc shape formed concentrically with the annular protrusion.

8. An electrostatic chuck device according to claim 7, wherein a radius of curvature R2 of the heat conduction suppressing portion is smaller than a radius of curvature R1 of the annular convex portion.

9. An electrostatic chuck device according to claim 6, wherein the heat conduction suppressing portion is circular in shape with a radius R3 smaller than the radius of curvature R1 of the annular convex portion when viewed in the thickness direction.

10. An electrostatic chuck device according to any one of claims 1 to 9, wherein the heat conduction suppressing portion is disposed within a hole or recess formed in the mounting surface.

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