Electrostatic chuck assembly

Abstract

Provided is an electrostatic chuck assembly that can extend durableness during use in a vacuum chamber in a multiplied manner. The electrostatic chuck assembly is provided with: a disc-shaped ceramic plate with built-in electrodes as an electrostatic chuck; a disc-shaped cooling plate that supports the bottom surface of the electrode built-in ceramic plate and has an annular or arcuate inner space; an annular or arc-shaped inner fixing member accommodated in the inner space so as to be rotatable with respect to the central axis of the cooling plate; a multiple of n (where n is an integer of 2 or more) female screw portions provided on the internal fixing member at intervals; and n holes which are provided in the bottom of the cooling plate so as to expose the n female screw portions of one group and into which bolts for fixing the chamber are inserted, each of the female screw portions being disposed such that the n female screw portions of the other group are exposed in the holes when the internal fixing member is rotated at a predetermined angle or an angle multiple of the predetermined angle.

Description

Technical Field

[0001] The present invention relates to electrostatic chuck assemblies. Background Art

[0002] Circuit formation in semiconductor device manufacturing is generally performed by plasma etching. Plasma etching is performed by introducing an inert gas into a vacuum chamber in a plasma etching device to plasmatize the chamber. An electrostatic chuck assembly is provided in the plasma etching device, and the electrostatic chuck assembly functions as a base for mounting a wafer to be etched. The electrostatic chuck assembly includes an electrode-built-in ceramic plate that functions as an electrostatic chuck and a cooling plate that supports the bottom surface of the electrode-built-in ceramic plate. The wafer is electrostatically adsorbed on the electrode-built-in ceramic plate, and plasma etching is performed while the wafer is fixed to the electrostatic chuck assembly. On the other hand, the cooling plate is provided on the bottom surface of the electrode-built-in ceramic plate, thereby being configured to capture the heat generated in the wafer due to plasma etching. As a method for installing the electrostatic chuck assembly in the vacuum chamber, fastening using bolts or screws is adopted.

[0003] Patent document 1 (Japanese Patent Gazette No. 4590393) discloses a substrate holder, which comprises: a ceramic substrate having a plurality of through holes; a plurality of cylindrical metal sockets, which are inserted into each through hole and have bolt holes; a first brazing material, which is arranged between the cylindrical metal socket and the through hole; a metal ring, which is embedded in the outer peripheral side wall of the ceramic substrate; and a second brazing material, which is arranged between the metal ring and the outer peripheral side wall of the ceramic substrate, and an electrode for electrostatically adsorbing the substrate to be processed is arranged inside the ceramic substrate. According to this structure, it is possible to suppress damage caused by bolt fixing.

[0004] Patent document 2 (Japanese Patent Gazette No. 6080571) discloses a mounting table for mounting a processed object, which comprises: a base having a refrigerant flow path formed inside and a power supply component capable of applying voltage connected to the back; a mounting component having a mounting surface for mounting the processed object; a focusing ring supported by the base; a first electric heating component interposed between the mounting surface and the refrigerant flow path; and a second electric heating component interposed between the focusing ring and the refrigerant flow path. The base is supported by a support table provided at the bottom of the processing container. Specifically, the base and the support table are positioned in such a manner that the through hole of the support table overlaps the through hole of the base, and screws are inserted from the back side of the support table to fix the screws, thereby connecting and fixing the base and the support table.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 4590393

[0008] Patent Document 2: Japanese Patent No. 6080571 Summary of the invention

[0009] As described above, as a method of mounting the electrostatic chuck assembly in the vacuum chamber, fastening with bolts or screws is used. Figure 7 and Figure 8 2 shows a conventional structure for assembling an electrostatic chuck assembly 110 or 110 ′ into a vacuum chamber 130 . Figure 7 and Figure 8 The conventional electrostatic chuck assembly 110 or 110 ′ shown has a ceramic plate 112 with an electrode built in, a cooling plate 114 supporting the bottom surface of the ceramic plate with an electrode built in, and an internal threaded portion 118 . Figure 7 The internal thread portion 118 shown has a structure in which the internal thread shape is directly cut out on the cooling plate 114. On the other hand, Figure 8 The internal threaded portion 118' shown is a component (e.g., a nut) having an internal thread shape cut out of a separate piece 119 (different from the cooling plate 114) disposed in a hole in the cooling plate 114. The bolt 122 inserted from the hole of the vacuum chamber 130 is screwed into the internal threaded portion 118 or 118' via an O-ring 132, thereby fixing the electrostatic chuck assembly 110 or 110' to the vacuum chamber 130. However, there is a risk that the internal threaded portion 118 or 118' may deteriorate and become unmountable as the electrostatic chuck assembly 110 or 110' is mounted or dismounted from the vacuum chamber 130.

[0010] This time, the inventors have obtained the following insights: a disc-shaped cooling plate having an annular or arc-shaped internal space and an annular or arc-shaped internal fixing component rotatably accommodated in the internal space are used, and a multiple of n internal threaded portions are provided on the internal fixing component so that the n internal threaded portions are exposed from an opening on the back side of the cooling plate. Thus, in the event that at least one of the n internal threaded portions is degraded, another group of n non-degraded internal threaded portions can be exposed in the opening simply by rotating the internal fixing component. As a result, the service life of the electrostatic chuck assembly can be extended exponentially.

[0011] Therefore, an object of the present invention is to provide an electrostatic chuck assembly that can multiply the durability period when used in a vacuum chamber.

[0012] According to the present invention, the following solutions are provided.

[0013] [Solution 1]

[0014] An electrostatic chuck assembly comprising:

[0015] The disc-shaped electrode that serves as the electrostatic chuck has a built-in ceramic plate;

[0016] A disc-shaped cooling plate, which supports the bottom surface of the electrode built-in ceramic plate and has an annular or arc-shaped internal space;

[0017] An annular or arc-shaped internal fixing member, which is accommodated in the internal space in a manner rotatable relative to the central axis of the cooling plate;

[0018] A multiple of n (where n is an integer greater than or equal to 2) of internal threaded portions, which are provided at intervals from each other on the internal fixing member; and

[0019] n openings are provided at the bottom of the cooling plate in such a way that a group of n internal threaded portions are exposed, and are used to insert bolts for fixing the chamber.

[0020] Each of the internal thread portions is arranged so that when the internal fixing member is rotated at a predetermined angle or a multiple thereof, another group of n internal thread portions are exposed in the opening.

[0021] [Solution 2]

[0022] The electrostatic chuck assembly according to claim 1, wherein n is 2-24.

[0023] [Solution 3]

[0024] The electrostatic chuck assembly according to claim 1 or 2, wherein the total number of the internal threaded portions is 2 to 5 times n.

[0025] [Solution 4]

[0026] The electrostatic chuck assembly according to any one of claims 1 to 3, wherein n is 12, and the total number of the internal threaded portions is 48, which is four times n.

[0027] [Solution 5]

[0028] The electrostatic chuck assembly according to any one of claims 1 to 4, wherein an identification mark is provided next to the internal thread portion of the internal fixing member in a manner that allows visual identification,

[0029] Furthermore, at least one of the n openings has an excess opening portion that enables the identification number to be visually recognized from the outside.

[0030] [Solution 6]

[0031] The electrostatic chuck assembly according to claim 5, wherein the opening having the excess opening portion is an arc-shaped opening.

[0032] [Solution 7]

[0033] The electrostatic chuck assembly according to claim 6, wherein the number of openings having the excess opening portion is 2.

[0034] [Scheme 8]

[0035] The electrostatic chuck assembly according to claim 7, wherein the two openings having the excess opening portion are arranged diagonally.

[0036] [Solution 9]

[0037] The electrostatic chuck assembly according to any one of claims 5 to 8, wherein the identification mark is imparted to the internal fixing member by engraving so as to be visible.

[0038] [Scheme 10]

[0039] An electrostatic chuck assembly according to any one of schemes 5 to 9, wherein the same identification mark is assigned to a group of n internal threaded portions that can be simultaneously exposed in the opening, and is different from the identification mark of the other groups of n internal threaded portions.

[0040] [Scheme 11]

[0041] According to the electrostatic chuck assembly of Scheme 10, the identification mark is a number, and the number is assigned to each of the internal threaded parts so that the internal threaded parts are arranged in sequence with consecutive numbers from 1 to m (wherein m is an integer greater than 2 and is a value obtained by dividing the total number of the internal threaded parts by n).

[0042] [Scheme 12]

[0043] An electrostatic chuck assembly according to any one of Schemes 5 to 11, wherein the internal fixing component is the annular component, and the center angle θ of the arc formed by the arc-shaped opening is greater than (360 / N) + θ1 degrees (wherein N is the total number of the internal threaded portions, and θ1 is the angle formed by two tangents drawn from the center of the cooling plate to the internal threaded portion when viewed from above).

[0044] [Scheme 13]

[0045] An electrostatic chuck assembly according to any one of Schemes 5 to 12, wherein the internal fixing component includes two or more arc-shaped components having a center angle of 360 / n degrees or more, and in each of the arc-shaped components, the center angle θ of the arc formed by the arc-shaped opening is greater than (360 / n) / N')+θ1 degrees (wherein N' is the number of the internal threaded portions in the arc-shaped component, and θ1 is the angle formed by two tangents drawn from the center of the cooling plate to the internal threaded portion when viewed from above).

[0046] [Scheme 14]

[0047] The electrostatic chuck assembly according to any one of claims 1 to 13, wherein the n internal thread portions are arranged to be spaced apart from each other at equal intervals. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1A It is a schematic cross-sectional view of an example of the electrostatic chuck assembly of the present invention.

[0049] Figure 1B yes Figure 1A A cross-sectional perspective view of an electrostatic chuck assembly is shown.

[0050] Figure 2A Viewed from the back of the cooling plate Figure 1A A schematic diagram of the electrostatic chuck assembly is shown.

[0051] Figure 2B It is shown in Figure 2A An enlarged view of the state where two internal threads on the back side of the cooling plate are exposed in the opening is shown.

[0052] Figure 3A It is a bottom view showing an example of the internal fixing member used in the present invention.

[0053] Figure 3B yes Figure 3A A 3B-3B cross-sectional view of the internal fixing component is shown.

[0054] Figure 3C It is a bottom view showing another example of the internal fixing member used in the present invention.

[0055] Figure 3D It is a bottom view showing another example of the internal fixing member used in the present invention.

[0056] Figure 3E It is a bottom view showing another example of the internal fixing member used in the present invention.

[0057] Figure 4 This is a flow chart showing the manufacturing process of the electrode-embedded ceramic plate used in the present invention.

[0058] Figure 5 1 is a flow chart showing the manufacturing process of the cooling plate used in the present invention.

[0059] Figure 6 This is a flow chart showing the manufacturing process of the electrostatic chuck assembly of the present invention and the process of installing it in a vacuum chamber.

[0060] Figure 7 FIG. 1 is a cross-sectional view schematically showing an example of a conventional electrostatic chuck assembly.

[0061] Figure 8 FIG. 1 is a cross-sectional view schematically showing another example of a conventional electrostatic chuck assembly. DETAILED DESCRIPTION

[0062] Electrostatic chuck assembly

[0063] Figure 1A and Figure 1B A schematic cross-sectional view of an electrostatic chuck assembly 10 according to one embodiment of the present invention is shown in FIG. The electrostatic chuck assembly 10 comprises: an electrode-built-in ceramic plate 12, a disc-shaped cooling plate 14, an annular or arc-shaped internal fixing component 16, internal threaded portions 18, 18', 18", and 18"', and an opening 20. The electrode-built-in ceramic plate 12 is a disc-shaped plate having a structure as an electrostatic chuck. The cooling plate 14 is a disc-shaped plate having an annular or arc-shaped internal space 14a, which supports the bottom surface of the electrode-built-in ceramic plate 12. The internal fixing component 16 is an annular or arc-shaped component, which is accommodated in the internal space 14a in a manner that allows rotation relative to the central axis of the cooling plate 14. The internal threaded portions 18, 18', 18", and 18"' are arranged in the internal fixing component 16 at intervals from each other. The number of the internal threaded portions 18, 18', 18", and 18"' is a multiple of n (where n is an integer greater than 2). The opening 20 is a hole for inserting a bolt 22 for fixing the chamber. Figure 2A As shown, the bottom of the cooling plate 14 is configured to expose a group of n internal threaded portions 18, so the number of openings 20 is n. In addition, each internal threaded portion 18, 18', 18", and 18"' is configured so that when the internal fixing member 16 is rotated at a specified angle or a multiple thereof, another group of n internal threaded portions 18', 18", or 18"' is exposed in the opening. In this way, by adopting a disc-shaped cooling plate 14 having an annular or arc-shaped internal space 14a and an annular or arc-shaped internal fixing component 16 rotatably accommodated in the internal space 14a, and by providing n multiples of internal threaded portions 18, 18', 18" and 18"' on the internal fixing component 16 and exposing the n internal threaded portions 18 from the opening 20 on the back side of the cooling plate 14, when at least one of the n internal threaded portions 18 is degraded, another group of n non-degraded internal threaded portions 18', 18" or 18"' can be exposed in the opening simply by rotating the internal fixing component 16, and as a result, the service life of the electrostatic chuck assembly can be extended exponentially.

[0064] That is, as described above, there is a risk that the internal thread portion 118 or 118' may deteriorate and become incapable of installation as the electrostatic chuck assembly 110 or 110' is installed or removed relative to the vacuum chamber 130. However, even in such a case, the electrostatic chuck assembly 10 of the present invention can expose the non-degraded internal thread portions 18', 18", or 18"' in sequence in the opening 20 simply by rotating the internal fixing member 16, so that the electrostatic chuck assembly 10 can be continuously used without being discarded by re-threading the bolt 22 therein. As a result, the service life of the electrostatic chuck assembly 10 can be extended by multiples (i.e., (total number of internal thread portions) / n times, 4 times in the illustrated example).

[0065] Considering the following conditions in the vacuum chamber of the plasma etching device, it is extremely advantageous to be able to extend the service life of the electrostatic chuck assembly 10 by multiple times. Figure 7 and Figure 8 In the existing structure shown, the torque applied to the bolt 122 used to install the electrostatic chuck assembly 110 or 110' is expected to be the value of the axial force required to flatten the O-ring 132 between the back side of the cooling plate 114 and the vacuum chamber 130 by a specified amount in an environment where atmospheric pressure is applied to the upper side in the vertical direction (the direction of arrow A in the figure). Although this value also depends on the nominal diameter and number of the bolts 122 used for fixing, for example, in the case of 12 bolts of 2.4T series material (such as carbon steel) and M6 (outer diameter 6mm), a high torque of 1Nm can be applied. In addition, since the temperature rises and falls repeatedly during the use of the electrostatic chuck assembly 110 or 110', not only the stress and reaction force generated when fixing the bolt 122, but also the thermal stress caused by the temperature rise and fall will be applied to the screw fixing portion. Therefore, in combination with Figure 7 and Figure 8 The conventional fixing method shown in the figure is easy to imagine that the interference between the threads may cause biting and damage to the threads (i.e., degradation of the internal thread portion 118 or 118'). In particular, even if the electrostatic chuck assembly 110 or 110' itself functions as a base without problems after use, the degradation of the internal thread portion 118 or 118' must limit the service life of the base, so it is imperative to improve the part involving the internal thread portion 118. In this way, it can be said that the problems caused by the degradation of the internal thread portion 118 or 118' as described above are particularly significant when used in a vacuum chamber of a plasma etching device. As a result, according to the present invention, these problems can be well solved.

[0066] Furthermore, the electrostatic chuck assembly 10 of the present invention is also advantageous in that it can cope with the following problems in addition to the problems associated with the degradation of the internal thread portion 118 or 118 ′.

[0067] exist Figure 7 and Figure 8 In the conventional structure shown, the portion fixed by the bolts 122 has a stronger tensile force in the vertical downward direction than the portion not fixed by the bolts 122, so there is also a problem that unevenness is easily generated on the surface 112a of the electrode-built-in ceramic plate 112. In this regard, according to the present invention, the clamping load generated by the fixing of the bolts 122 is dispersed by the annular or arc-shaped internal fixing member 16, so the unevenness of the surface 112a of the electrode-built-in ceramic plate 112 caused by the installation of the electrostatic chuck assembly 10 becomes lighter than before.

[0068] exist Figure 8 In the conventional structure shown, when the bolt 122 is fixed, it is necessary to have a shape that suppresses the rotation of the independent part 119 (for example, a hexagon like a nut, double chamfers, etc.). However, if the independent part 119 is small, it is impossible to ensure a large size of the rotation suppression shape, and the rotation suppression effect becomes insufficient. Moreover, if the rotation suppression shape is deformed, it is also impossible to fix it with the bolt 122. In this regard, according to the present invention, the internal fixing part 16 is annular or arc-shaped, so that the side of the internal fixing part 16 is limited by the inner wall of the annular or arc-shaped internal space 14a in the cooling plate 14 over a sufficient length, thereby effectively suppressing the rotation associated with the fixing of the bolt 122.

[0069] The electrostatic chuck assembly 10 is used as a stage for mounting a wafer in order to perform CVD, etching, etc. on the wafer using plasma, and is fixed to a vacuum chamber 30 (particularly, the lower part of the chamber) for manufacturing semiconductor devices.

[0070] The electrostatic chuck assembly 10 includes an electrode-embedded ceramic plate 12 and a cooling plate 14. The cooling plate 14 may be bonded to a back surface 12b of the electrode-embedded ceramic plate 12 opposite to a front surface 12a as a wafer placement surface via a bonding layer 13.

[0071] The electrode-built-in ceramic plate 12 may be a structure commonly used as an electrostatic chuck. A typical electrode-built-in ceramic plate 12 includes a disc-shaped ceramic base 12c and an electrostatic electrode 12d and a heater electrode 12e buried in the ceramic base 12c at intervals in the thickness direction. In the ceramic base 12c, the electrostatic electrode 12d is arranged at a position close to the surface 12a, and on the other hand, the heater electrode 12e is arranged at a position close to the back surface 12b. Examples of ceramic materials constituting the ceramic base 12c include aluminum nitride, silicon carbide, silicon nitride, aluminum oxide, and the like.

[0072] The electrostatic electrode 12d may be a conductive layer (e.g., a conductive mesh or plate) and is arranged parallel to the surface 12a. The back of the electrostatic electrode 12d is connected to a power supply rod 34 inserted into the ceramic substrate 12c, and the power supply rod 34 passes through the vacuum chamber 30, the cooling plate 14, and the bonding layer 13. A DC voltage is applied to the electrostatic electrode 12d via the power supply rod 34.

[0073] The heater electrode 12e is made of a conductive coil or printed pattern, and is formed so as to be connected from one end to the other end in a single stroke across the entire electrode-embedded ceramic plate 12 in a plan view. One end and the other end of the heater electrode 14e are connected to a pair of power supply rods (not shown) inserted into the ceramic base 12c, and the pair of power supply rods penetrate the vacuum chamber 30, the cooling plate 14, and the bonding layer 13. A voltage is applied to the heater electrode 12e via the power supply rods.

[0074] However, the electrodes embedded in the ceramic substrate 12c are not limited to the electrostatic electrodes 12d and the heater electrodes 12e, but may be other types of electrodes, and the number of layers of embedded electrodes is not limited to 2 layers, but may be 3 layers or more. For example, four layers of electrodes, namely, an electrostatic electrode for a wafer, a bias electrode for a wafer, an electrostatic electrode for a focus ring, and a bias electrode for a focus ring, may be embedded in the ceramic substrate 12c in order from the surface 12a toward the back surface 12b, spaced apart from each other.

[0075] The cooling plate 14 is a disc-shaped plate supporting the bottom surface of the electrode built-in ceramic plate 12, and has an annular or arc-shaped internal space 14a for accommodating the internal fixing member 16. The internal space 14a is formed into a structure in which the internal fixing member 16 can be rotatably accommodated relative to the central axis of the cooling plate 14. In addition to having the internal space 14a, the cooling plate 14 can also have the structure of a cooling plate commonly used in an electrostatic chuck. The cooling plate 14 can be made of metal such as aluminum and aluminum alloy, or can be made of a metal matrix composite material (Metal Matrix Composite (MMC)) such as SiSiCTi (a composite material containing Si, SiC and Ti). A typical cooling plate 14 is disc-shaped and has a flow path 14b inside that can circulate a refrigerant. The flow path 14b is connected to a refrigerant supply path and a refrigerant discharge path (not shown) that penetrate the vacuum chamber 30, and the refrigerant discharged from the refrigerant discharge path returns to the refrigerant supply path again after temperature adjustment. The cooling plate 14 has a flange portion 14 c formed so that a lower portion (a portion close to the vacuum chamber 30 ) of the cooling plate 14 extends in the diameter expansion direction.

[0076] The cooling plate 14 can be bonded to the back side 12b of the electrode-built-in ceramic plate 12 via the bonding layer 13. The bonding layer 13 can be either a bonding sheet or a metal layer such as an aluminum alloy layer. In particular, when the cooling plate 14 is made of a metal matrix composite material (MMC) such as SiSiCTi, it is preferred to bond the cooling plate 14 to the back side 12b of the electrode-built-in ceramic plate 12 using TCB (Thermal Compression Bonding). TCB refers to a well-known method of sandwiching a metal bonding material between two components of the bonding object and pressurizing and bonding the two components while heating to a temperature below the solidus temperature of the metal bonding material. As an example of a metal bonding material, an aluminum alloy can be cited.

[0077] The internal fixing member 16 is an annular or arc-shaped member, and is housed in the internal space 14a in a manner rotatable relative to the central axis of the cooling plate 14. Therefore, the internal fixing member 16 is formed in a shape that matches the internal space 14a. The internal fixing member 16 may be as follows: Figure 2A , Figure 3A as well as Figure 3B As shown in the figure, it can also be annular Figure 3C to Figure 3E As shown, arc-shaped components 16', 16" or 16'" are provided at various center angles. Figure 3C , Figure 3D and Figure 3E The central angles of the arc-shaped internal fixing member 16 shown are approximately 45°, approximately 90°, and approximately 135°, respectively. When the internal fixing member 16 is formed in an arc shape, the internal space 14a of the cooling plate 14 may be annular or arc-shaped. When the internal space 14a of the cooling plate 14 is in an arc shape, the arc-shaped internal fixing member 16 needs to be accommodated in the internal space 14a in a manner that allows rotation relative to the central axis, and therefore it is desirable that the central angle of the arc shape of the internal space 14a is larger than the central angle of the arc-shaped internal fixing member 16.

[0078] The internal fixing member 16 may be made of a material capable of forming the internal thread portion 18. Examples of such a material include metals such as titanium and stainless steel.

[0079] The internal threaded portions 18, 18', 18", and 18'" are provided at intervals from each other on the internal fixing member 16. The total number of the internal threaded portions 18, 18', 18", and 18'" is a multiple of n (where n is an integer greater than or equal to 2). Figure 2A as well as Figure 3AIn the illustrated embodiment, the number of internal threaded portions 18, the number of internal threaded portions 18', the number of internal threaded portions 18", and the number of internal threaded portions 18'' are 12 respectively, that is, n=12, and the number of categories of internal threaded portions 18, 18', 18", and 18'' is 4, so the total number of internal threaded portions 18, 18', 18", and 18'' is n×4=12×4=48. It should be noted that the internal threaded portions 18, 18', 18", and 18'' are expected to be internal threaded portions of the same shape and size as each other, and the different figure marks denoted as 18, 18', 18", and 18'' are merely figure marks added for the convenience of distinguishing them from each other. However, Figure 2A and Figure 3A The types and total number of the internal threaded portions 18 , 18 ′, 18 ″, and 18 ′″ shown are merely examples, and the present invention is not limited thereto.

[0080] The value of n is not particularly limited as long as it is an integer greater than 2, and is preferably 2 to 24, typically 3 to 20, and more typically 5 to 15. The total number of the internal thread portions 18, 18', 18", and 18'" is preferably 2 to 5 times n. Most preferably, Figure 2A as well as Figure 3A As shown, the value of n is 12, and the total number of the internal threaded portions 18, 18', 18" and 18'" is 4 times n (ie, 48). Preferably, the n internal threaded portions 18, 18', 18" and 18'" are spaced apart from each other at equal intervals.

[0081] The openings 20 are holes for inserting bolts 22 for fixing the chamber, and n openings 20 are provided at the bottom of the cooling plate 14 so that a group of n internal threaded portions 18 are exposed. The openings 20 are preferably formed to be slightly larger than the outer diameters of the internal threaded portions 18, 18', 18", and 18'" except for the case where the openings 20 have excess openings 20a described later, so that the bolts 22 can be easily inserted into the internal threaded portions 18.

[0082] Each of the internal threaded portions 18, 18', 18", and 18'" is configured so that when the internal fixing member 16 is rotated at a predetermined angle or a multiple thereof, another group of n internal threaded portions 18', 18", or 18'" is exposed in the opening 20. The another group of n internal threaded portions 18', 18", or 18'" refers to a group of internal threaded portions that are different from the internal threaded portion (the internal threaded portion 18 in the example shown) that can be exposed in n openings 20 at the same time (in the example shown, a combination of n internal threaded portions 18', a combination of n internal threaded portions 18", or a combination of n internal threaded portions 18'" in the example shown). Thus, when the internal threaded portion 18 exposed in the opening 20 deteriorates due to use, by rotating the internal fixing member 16 at a predetermined angle or a multiple thereof, the group of unused internal threaded portions 18', 18", or 18'" can be exposed in the opening 20 and used anew. That is, the bolt 22 can be screwed into the unused internal threaded portion 18', 18", or a combination of 18". As a result, the service life of the electrostatic chuck assembly 10 when used in a vacuum chamber can be extended by several times.

[0083] Preferably, identification marks (1, 2, 3 and 4 in the example shown) are given in a visually recognizable manner next to the internal threaded portions 18, 18', 18", and 18'" of the internal fixing component 16, and at least one of the n openings 20 has an excess opening portion 20a whose serial number can be visually identified from the outside. As a result, the internal threaded portions 18 of the used group and the internal threaded portions 18', 18", or 18'" of the unused group can be distinguished from the excess opening portion 20a by the identification mark, and the internal threaded portions 18', 18", or 18'" of the unused group that should be exposed in the opening 20 next can be easily and appropriately selected. Therefore, it is preferred that the same identification mark is assigned to the n internal threaded portions 18, 18', 18", or 18'" of a group that can be exposed simultaneously in the opening 20, and that the identification mark is different from that of the n internal threaded portions 18, 18', 18", or 18'" of other groups. For example, Figure 2A and Figure 3A As shown, it is preferred that the identification mark is a number, and the numbers are assigned to the internal threaded portions 18, 18', 18", and 18'" so that the internal threaded portions 18, 18', 18", and 18'" are arranged in sequence with consecutive numbers from 1 to m (wherein m is an integer greater than 2 and is a value obtained by dividing the total number of internal threaded portions by n). In this case, it is sufficient to sequentially determine the internal threaded portions that should be exposed in the opening 20 according to the identification numbers. It is preferred that the identification mark is given to the internal fixing member 16 by engraving in a manner that can be visually recognized. If it is engraved, it is advantageous in that the identification mark is difficult to erase even after long-term use.

[0084] The opening 20 having the excess opening 20a is preferably an arc-shaped opening. In addition, preferably there are two openings 20 having the excess opening 20a, and more preferably, the two openings 20 having the excess opening 20a are arranged diagonally.

[0085] In the case where the internal fixing member 16 is an annular member, as Figure 2B As shown, the central angle θ of the arc formed by the arc-shaped opening 20 (the opening 20 having the excess opening 20a) is greater than (360 / N)+θ1 degrees (where N is the total number of the internal thread portions 18, 18', 18", and 18'", and θ1 is the angle formed by two tangent lines drawn from the center of the cooling plate 14 to the internal thread portion 18, 18', 18", or 18'" in a top view). According to this structure, after the internal thread portion 18 is finished and the bolt 22 is removed, the internal fixing member 16 can be easily rotated relative to the center axis by simply inserting a rod or a finger into the internal thread portion 18. Figure 2B As shown, the unused internal threaded portion 18', 18", or 18'" to be used next is exposed in the arc-shaped opening 20. That is, not only the used internal threaded portion 18 can be exposed, but also the unused internal threaded portion 18', 18", or 18'" can be exposed in the same arc-shaped opening 20. In particular, the internal fixing component 16 is accommodated in the internal space 14a of the cooling plate 14, and the portion of the internal fixing component 16 exposed to the outside only exists in the portion corresponding to the opening 20. Therefore, it takes effort to rotate the internal fixing component 16, but the internal fixing component 16 can be easily rotated according to the above method.

[0086] The same method can also be applied to the arc-shaped parts 16', 16" or 16'". In this case, the internal fixing part 16 includes two or more arc-shaped parts 16', 16" and / or 16'" having a central angle of 360 / n degrees or more. Moreover, preferably, in each arc-shaped part 16', 16" and 16'", the central angle θ of the arc formed by the arc-shaped opening 20 (the opening 20 having the excess opening portion 20a) is greater than (360 / n) / N')+θ1 degrees (wherein N' is the number of internal threaded portions in the arc-shaped part 16', 16" or 16'", and θ1 is the angle formed by two tangent lines drawn from the center of the cooling plate to the internal threaded portion 18, 18', 18" or 18'" when viewed from above).

[0087] Manufacturing method

[0088] The electrostatic chuck assembly of the present invention can be manufactured according to a known method, and its manufacturing method is not particularly limited. For example, the parts for the electrode built-in ceramic plate 12, the cooling plate 14 and the internal fixing member 16 are separately manufactured, and these parts are joined by TCB, thereby making the electrostatic chuck assembly 10. Figures 4 to 6 Each process is described.

[0089] (1) Fabrication of electrode-embedded ceramic plates

[0090] First, a slurry containing ceramic raw material powder, a binder, a dispersion medium, etc. is prepared. Examples of ceramic raw material powder include aluminum nitride powder, silicon carbide powder, silicon nitride powder, and aluminum oxide powder. The slurry is filtered, and a curing agent is added and mixed. The obtained slurry is poured into a mold and dried. The dried green sheet is degreased, pre-sintered, and processed to obtain a disc-shaped green sheet 42. Figure 4 In the embodiment, three green sheets 42 are prepared, but the number of green sheets 42 is not limited thereto, and four or more green sheets 42 may be used. Here, for the sake of convenience, the description is given on the premise that three green sheets 42 are used.

[0091] like Figure 4 As shown in (a), the electrodes 12d or 12e are printed on two green sheets 42 in advance. Then, three green sheets 42 are stacked so that the electrodes 12d and 12e are sandwiched between the green sheets 42. Figure 4 As shown in (b), the obtained laminate is fired by hot pressing. Figure 4 As shown in (c), the fired laminate is machined to form holes that can be connected to the electrodes 12d and 12e. Thus, the electrode-embedded ceramic plate 12 is obtained.

[0092] (2) Manufacturing of cooling plate parts

[0093] like Figure 5 As shown in (a), after the MMC raw material powder is extruded to obtain a powder compact 44, as shown in Figure 5 As shown in (b), the powder compact 44 is sintered by hot pressing. In this way, three MMC sintered bodies 46 are produced. Figure 5 As shown in (c), three MMC sintered bodies 46 are machined to form internal spaces 14a and / or flow paths 14b. In this way, cooling plate parts 48a, 48b and 48c are obtained. Figure 5 Although three cooling plate parts 48a, 48b and 48c are prepared, the number of cooling plate parts is not limited thereto, and four or more cooling plate parts may be used.

[0094] (3) Fabrication of internal fixing parts

[0095] The titanium material is machined to obtain Figure 3A as well as Figure 3B As shown, the annular internal fixing member 16 is formed with internal thread portions 18, 18', 18" or 18'" at equal intervals.

[0096] (4) Assembly and installation of electrostatic chuck components

[0097] like Figure 6 As shown in (a), the electrode-built-in ceramic plate 12, the three cooling plate parts 48a, 48b and 48c and the internal fixing member 16 are assembled in such a way that the internal fixing member 16 is accommodated in the internal space 14a. At this time, the aluminum alloy sheet 43 is interposed between the electrode-built-in ceramic plate 12 and the cooling plate parts 48 and between the cooling plate parts 48. Figure 6 As shown in (b), TCB is performed to bond the electrode-embedded ceramic plate 12 and the cooling plate component 48c, and the cooling plate components 48a, 48b, and 48c to each other. Figure 6 As shown in (c), the obtained assembly is subjected to additional processing, terminal bonding, spraying, sleeve bonding, etc. to obtain an electrostatic chuck assembly 10. Finally, as shown in Figure 6 As shown in (d), the electrostatic chuck assembly 10 is arranged in the vacuum chamber 30 via the O-ring 32, and the bolt 22 is passed through the hole of the vacuum chamber 30 (especially its support plate), inserted into the internal thread portion 18 exposed in the opening 20, and then screwed. In this way, the electrostatic chuck assembly 10 is fixed to the vacuum chamber 30.

Claims

1. An electrostatic chuck assembly comprising: The disc-shaped electrode that serves as the electrostatic chuck has a built-in ceramic plate; A disc-shaped cooling plate, which supports the bottom surface of the electrode built-in ceramic plate and has an annular or arc-shaped internal space; An annular or arc-shaped internal fixing member, which is accommodated in the internal space in a manner rotatable relative to the central axis of the cooling plate; n multiples of internal thread portions are arranged at intervals from each other on the inner fixing member, wherein: n is an integer greater than 2; and n openings are provided at the bottom of the cooling plate in such a way that a group of n internal threaded portions are exposed, and are used to insert bolts for fixing the chamber. Each of the internal thread portions is arranged so that when the internal fixing member is rotated at a predetermined angle or a multiple thereof, another group of n internal thread portions are exposed in the opening.

2. The electrostatic chuck assembly according to claim 1, characterized in that: The n is 2-24.

3. The electrostatic chuck assembly according to claim 1 or 2, characterized in that: The total number of the internal threaded portions is 2 to 5 times of n.

4. The electrostatic chuck assembly according to claim 1 or 2, characterized in that: The n is 12, and the total number of the internal threaded portions is 4 times the n, that is, 48.

5. The electrostatic chuck assembly according to claim 1 or 2, characterized in that: An identification mark is provided next to the internal thread portion of the internal fixing member in a manner that allows visual identification. Furthermore, at least one of the n openings has an excess opening portion that enables the identification number to be visually recognized from the outside.

6. The electrostatic chuck assembly according to claim 5, characterized in that: The opening having the excess opening portion is an arc-shaped opening.

7. The electrostatic chuck assembly according to claim 6, wherein: There are 2 openings with the excess opening.

8. The electrostatic chuck assembly according to claim 7, wherein: The two openings having the excess openings are arranged diagonally.

9. The electrostatic chuck assembly according to claim 5, characterized in that: The identification mark is given to the internal fixing member by engraving so as to be visible.

10. The electrostatic chuck assembly according to claim 5, wherein: The same identification mark is assigned to a group of n internal threaded portions that can be exposed simultaneously in the opening, and is assigned a different identification mark from that of the other groups of n internal threaded portions.

11. The electrostatic chuck assembly according to claim 10, wherein: The identification mark is a number, and the number is assigned to each of the internal threaded parts so that the internal threaded parts are arranged in sequence with consecutive numbers from 1 to m, where m is an integer greater than 2 and is a value obtained by dividing the total number of the internal threaded parts by n.

12. The electrostatic chuck assembly according to claim 5, wherein: The internal fixing component is the annular component, and the central angle θ of the arc formed by the arc-shaped opening is greater than (360 / N)+θ1 degrees, wherein N is the total number of the internal threaded portions, and θ1 is the angle formed by two tangent lines drawn from the center of the cooling plate to the internal threaded portion when viewed from above.

13. The electrostatic chuck assembly according to claim 5, wherein: The internal fixing component includes two or more arc-shaped components with a central angle of 360 / n degrees or more. In each of the arc-shaped components, the central angle θ of the arc formed by the arc-shaped opening is greater than (360 / n) / N')+θ1 degrees, wherein N' is the number of the internal threaded portions in the arc-shaped component, and θ1 is the angle formed by two tangents drawn from the center of the cooling plate to the internal threaded portion when viewed from above.

14. The electrostatic chuck assembly according to claim 1 or 2, characterized in that: The n internal thread portions are arranged to be spaced apart from each other at equal intervals.

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