Electrostatic chuck manufacturing method and electrostatic chuck

Abstract

This method for manufacturing an electrostatic chuck (1) comprises: a recess forming step of forming a recess (11a) in a formation-planned region for a conductor pattern (21) on a first surface (11b) side of a first insulator substrate (11); a conductor pattern forming step of forming the conductor pattern (21) inside the recess (11a); and a bonding step of, after the conductor pattern forming step, bonding a second insulator substrate (12) to the first insulator substrate (11) in a state in which a second surface (12b) side of the second insulator substrate (12) is in surface contact with the first surface (11b) side of the first insulator substrate (11).

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electrostatic chuck and an electrostatic chuck. [Background technology]

[0002] A method for manufacturing an electrostatic chuck has been proposed, which includes the steps of calcining two plate-shaped ceramic compacts to produce two calcined ceramic bodies, printing a paste containing tungsten on one surface of the two calcined ceramic bodies to form an electrostatic electrode, and hot-pressing and firing the two calcined ceramic bodies in a state where the two calcined ceramic bodies are stacked together with the electrostatic electrode sandwiched between them, thereby producing a ceramic sintered body (see, for example, Patent Document 1). Here, in the hot-press firing, the two calcined ceramic bodies and the electrostatic electrode are pressed together under a pressure of 100 kg / cm in a nitrogen atmosphere. 2 The maximum temperature is 1000°C and held for 2 hours. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-216816 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the manufacturing method of an electrostatic chuck described in Patent Document 1, the electrostatic electrode is heated to a maximum temperature of 1000°C in the above-mentioned hot press firing, making it difficult to use a transparent electrode with low heat resistance as the electrostatic electrode.

[0005] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide an electrostatic chuck manufacturing method and an electrostatic chuck that can increase the variety of materials for forming a conductive pattern. [Means for solving the problem]

[0006] In order to achieve the above object, a method for manufacturing an electrostatic chuck according to the present invention includes: a recess forming step of forming a recess in a region on the first surface side in the thickness direction of the first insulating substrate where a conductor pattern is to be formed; a conductor pattern forming step of forming the conductor pattern inside the recess; and a joining step of joining the second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be joined to the first insulator substrate in a thickness direction of the second insulator substrate is brought into surface contact with the first surface side of the first insulator substrate after the conductor pattern forming step. fruit, In the bonding step, the second insulating substrate is bonded to the first insulating substrate while maintaining the temperature of the second insulating substrate at 700° C. or less. .

[0007] From another aspect, the electrostatic chuck according to the present invention comprises: a first insulating substrate having a recess formed on a first surface side in a thickness direction; a conductor pattern formed inside the recess; a second insulating substrate that is bonded to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and that forms a bonding interface between a second surface side in a thickness direction of the first insulating substrate and the first surface side of the first insulating substrate and the conductor pattern. picture, the second insulating substrate has a ceramic material region formed from a ceramic material and arranged so as to be exposed at least on a side of the second insulating substrate opposite to the first insulating substrate side; The ceramic material contains a metal element. . [Effects of the Invention]

[0008] According to the present invention, in the bonding step after the conductive pattern forming step, the electrostatic chuck is fabricated by bonding the second insulator substrate to the first insulator substrate in a state in which the second surface side of the second insulator substrate is in surface contact with the first surface side of the first insulator substrate. This allows the conductive patterns to be formed from a material with a relatively low allowable temperature range, thereby increasing the variety of materials for forming the conductive patterns. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a cross-sectional view of a portion of an electrostatic chuck according to an embodiment of the present invention. [Figure 2A] FIG. 1 is a schematic plan view of an electrostatic chuck according to an embodiment. [Figure 2B] 2B is a partially enlarged view of the electrostatic chuck according to the embodiment; FIG. [Figure 3] FIG. 1 is a plan view showing a portion of an electrostatic chuck according to an embodiment. [Figure 4A] FIG. 1 is a schematic diagram of an electrostatic chuck according to an embodiment. [Figure 4B] FIG. 4 is a diagram showing a time waveform of a voltage output from a chuck driving unit of the electrostatic chuck according to the embodiment. [Figure 4C] FIG. 4 is a diagram showing a time waveform of a current supplied from a chuck driving unit of the electrostatic chuck according to the embodiment. [Figure 5A] 4 is a cross-sectional view showing a step of placing a mask on the first surface side of the first insulator substrate in the method for manufacturing an electrostatic chuck according to the embodiment. FIG. [Figure 5B] 10A to 10C are cross-sectional views showing an etching step in the method for manufacturing an electrostatic chuck according to the embodiment. [Figure 5C] 5A to 5C are cross-sectional views showing a step of forming a conductive pattern in a manufacturing method of an electrostatic chuck according to an embodiment. [Figure 5D] 4A to 4C are cross-sectional views illustrating a step of joining a second insulator substrate to a first insulator substrate in a manufacturing method of an electrostatic chuck according to an embodiment. [Figure 6A] FIG. 10 is a partial cross-sectional view showing a state after a conductive pattern forming step in a manufacturing method for an electrostatic chuck according to a comparative example. [Figure 6B] FIG. 10 is a partial cross-sectional view showing a state after a bonding step in a manufacturing method of an electrostatic chuck according to a comparative example. [Figure 6C] FIG. 10 is a partial cross-sectional view showing a state after a conductive pattern forming step in the method for manufacturing an electrostatic chuck according to the embodiment. [Figure 6D] FIG. 10 is a partial cross-sectional view showing a state after a bonding step in the method for manufacturing an electrostatic chuck according to the embodiment. [Figure 7A]10A and 10B are diagrams illustrating the operation of an electrostatic chuck according to a comparative example. [Figure 7B] 10A and 10B are diagrams illustrating the operation of an electrostatic chuck according to a comparative example. [Figure 7C] 5A to 5C are diagrams illustrating the operation of the electrostatic chuck according to the embodiment. [Figure 8] FIG. 10 is a diagram showing a stage and a head equipped with an electrostatic chuck according to a modified example. [Figure 9A] FIG. 10 is a plan view of a part of a first region of a second insulating substrate according to a modified example. [Figure 9B] FIG. 10 is a plan view of a part of a second region of a second insulating substrate according to a modified example. [Figure 10A] FIG. 10 is a diagram showing a voltage waveform output from a chuck driving unit according to a modified example when holding an object to be held. [Figure 10B] FIG. 10 is a diagram showing a voltage waveform output from a chuck driving unit according to a modified example when the held object is released. [Figure 11] FIG. 10 is a cross-sectional view of a portion of an electrostatic chuck according to a modified example. [Figure 12A] FIG. 10 is a diagram showing a state in which an electrostatic chuck according to a modified example holds a substrate. [Figure 12B] FIG. 10 is a diagram showing a state in which the electrostatic chuck according to the modified example bends the substrate. [Figure 12C] 10A and 10B are diagrams showing how the bonding of substrates held by an electrostatic chuck according to a modified example progresses. [Figure 12D] FIG. 10 is a diagram showing a state in which substrates held by an electrostatic chuck according to a modified example are bonded together at their entire surfaces. [Figure 13A] FIG. 10 is a diagram showing a spectrum of transmitted light passing through a second insulator substrate in a thickness direction of the electrostatic chuck according to the modified example. [Figure 13B] FIG. 10 is a diagram showing a transmitted light spectrum of light transmitted in a thickness direction of a second insulator substrate in an electrostatic chuck according to a comparative example and a transmitted light spectrum of light transmitted in a thickness direction of a second insulator substrate in an electrostatic chuck according to a modified example. [Figure 14] FIG. 10 is a cross-sectional view of a portion of an electrostatic chuck according to a modified example. [Figure 15A]FIG. 10 is a partial cross-sectional view showing a state after a chamfering step in a manufacturing method of an electrostatic chuck according to a modified example. [Figure 15B] FIG. 10 is a partial cross-sectional view showing a state after a polishing step in a manufacturing method of an electrostatic chuck according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a method for manufacturing an electrostatic chuck according to an embodiment of the present invention will be described with reference to the drawings. The method for manufacturing an electrostatic chuck according to the present embodiment includes a recess forming step of forming a recess in a region on a first surface side in a thickness direction of a first insulating substrate where a conductive pattern is to be formed, a conductive pattern forming step of forming a conductive pattern inside the recess, and a bonding step of bonding a second insulating substrate to the first insulating substrate in a state in which a second surface side in the thickness direction of the second insulating substrate is in surface contact with the first surface side of the first insulating substrate while maintaining the temperature at 200° C. or less.

[0011] As shown in FIG. 1 , an electrostatic chuck 1 manufactured by the electrostatic chuck manufacturing method according to this embodiment includes a first insulator substrate 11 having a recess 11a formed on a first surface 11b side in the thickness direction, a conductive pattern 21 formed inside the recess 11a, and a second insulator substrate 12 bonded to the first insulator substrate 11 so as to cover the entire first surface 11b side of the first insulator substrate 11. A bonding interface I is formed between the first surface 11b side of the first insulator substrate 11 and the conductive pattern 21 and the second surface 12b side of the second insulator substrate 12. The first insulator substrate 11 and the second insulator substrate 12 are each formed in a disk shape from a light-transmitting insulating material, as shown in FIG. 2A . At least one of the first insulator substrate 11 and the second insulator substrate 12 may be formed from a non-light-transmitting insulating material. Examples of the insulating material include glass and sintered ceramics. As the ceramic sintered body, those containing Al2O3, Y2O3, AlN, SiN, SiC, Sm2O3, MgO, MgF2, Yb2O3, etc. as a main component can be used.

[0012] 2A and 2B, when the electrostatic chuck 1 holds a disk-shaped substrate (not shown) as a held object, the conductor pattern 21 includes conductor patterns 21A and 21B provided in a first annular region A1 facing the periphery of the substrate, and a conductor pattern 21C provided in a second annular region A2, which is circular in plan view and inside the first region A1. The conductor patterns 21A and 21B are provided in two predetermined sub-annular regions A11 and A12, respectively, centered on the centers of the first and second insulating substrates 11 and 12 in the first region A1. The conductor patterns 21A, 21B, and 21C are made of a metal such as Cu or Al. The conductor patterns 21A, 21B, and 21C may be made of a transparent electrode material, specifically, at least one material selected from ITO, ZnO, TiO, and graphene. In this case, a camera for capturing an image of the alignment marks provided on the substrate is disposed on the side of electrostatic chuck 1 opposite to the side that holds the substrate, making it possible to capture an image of the alignment marks of the substrate held by electrostatic chuck 1 through conductive patterns 21A, 21B, and 21C. Here, the distance between conductive pattern 21 and the surface of second insulator substrate 12 opposite to first insulator substrate 11 is preferably 0.1 mm or less. In addition, the distance between adjacent electrodes 2111b, 2112b, 2121b, and 2122b is preferably 2.0 mm or less.

[0013] In the sub-annular region A11, the conductor pattern 21A includes a plurality of electrode elements 2111b, 2112b extending radially from the center of the first insulator substrate 11 and the second insulator substrate 12 toward the periphery of the first insulator substrate 11 and the second insulator substrate 12, and two annular terminal electrodes 2111a, 2112a arranged along the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12. As shown in FIG. 3 , the plurality of electrode elements 2111b, 2112b extend radially from the two terminal electrodes 2111a, 2112a toward the other terminal electrode 2112a, 2111a. The terminal electrode 2111a has a smaller diameter than the terminal electrode 2112a and is arranged closer to the center of the first insulator substrate 11 and the second insulator substrate 12. The multiple elongated electrode elements 2111b, 2112b are arranged alternately along the circumferential direction of the first region A1 in the first region A1 of the first insulator substrate 11 and the second insulator substrate 12. The terminal electrodes 2111a, 2112a each have bent portions 2111ab, 2112ab that are bent so as to protrude in a direction away from the other terminal electrode 2111a, 2112a in a plan view, and elongated connecting portions 2111aa, 2112aa that extend along the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12 and connect end portions of two bent portions 2111ab, 2112ab that are adjacent in the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12.

[0014] 2A, in the sub-annular region A12, the conductor pattern 21B has a plurality of electrode elements 2121b, 2122b extending radially from the central portions of the first and second insulator substrates 11, 12 toward the peripheral edges of the first and second insulator substrates 11, 12, and two annular terminal electrodes 2121a, 2122a disposed along the circumferential direction of the first and second insulator substrates 11, 12. As shown in FIG. 3, the plurality of electrode elements 2121b, 2122b extend radially from the two terminal electrodes 2121a, 2122a toward the other terminal electrode 2122a, 2121a. The terminal electrode 2121a has a smaller diameter than the terminal electrode 2122a, and is disposed toward the center of the first insulator substrate 11 and the second insulator substrate 12. The multiple long electrode elements 2121b, 2122b are arranged alternately in the circumferential direction of the first region A1 in the first insulator substrate 11 and the second insulator substrate 12. In addition, the terminal electrodes 2121a, 2122a each have a bending portion 2121ab, 2122ab that is bent so as to protrude in a direction away from the other terminal electrode 2121a, 2122a when viewed in a plane, and a long, slender connecting portion 2121aa, 2122aa that extends along the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12 and connects the ends of two adjacent bending portions 2121ab, 2122ab in the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12.

[0015] In this manner, since the conductive patterns 21A and 21B have the bent portions 2111ab, 2112ab, 2121ab, and 2122ab and the connecting portions 2111aa, 2112aa, 2121aa, and 2122aa, respectively, particularly when the conductive patterns 21A and 21B are made of metal, it is possible to prevent an alignment mark provided on the substrate from overlapping with any of the bent portions 2111ab, 2112ab, 2121ab, and 2122ab or the connecting portions 2111aa, 2112aa, 2121aa, and 2122aa by adjusting the positions of the electrostatic chuck 1 and the substrate held by the electrostatic chuck 1 in the rotational direction around the center of the electrostatic chuck 1. Therefore, for example, even if a camera for capturing an image of the alignment mark provided on the substrate is located on the opposite side of the electrostatic chuck 1 from the side that holds the substrate, it is possible to capture a good image of the alignment mark provided on the substrate held by the electrostatic chuck 1.

[0016] 2A , the conductor pattern 21C is provided in a second region A2 inside the first region A1 of the first insulator substrate 11 and the second insulator substrate 12. The conductor pattern 21C has a plurality of electrode elements 2131b, 2132b extending radially from the central portions of the first insulator substrate 11 and the second insulator substrate 12 toward the peripheries of the first insulator substrate 11 and the second insulator substrate 12, and two annular terminal electrodes 2131a, 2132a disposed along the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12. The multiple electrode elements 2131b, 2132b include two arc-shaped terminal electrodes 2131a, 2132a extending in the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12, and extending from each of the two terminal electrodes 2131a, 2132a toward the other terminal electrodes 2132a, 2131a along the radial direction of the first insulator substrate 11 and the second insulator substrate 12. As shown in Fig. 2B , each of the multiple electrode elements 2131b, 2132b has a wedge-shaped shape in plan view, whose width in a direction perpendicular to the extending direction in plan view increases toward the peripheral edge of the first insulator substrate 11 and the second insulator substrate 12.

[0017] The conductor patterns 21A, 21B, and 21C are connected to a chuck driver 4. The chuck driver 4 drives the electrostatic chuck 1 by applying voltages to the conductor patterns 21A, 21B, and 21C. The chuck driver 4 can change the substrate chucking state by selectively applying voltages to the conductor patterns 21A, 21B, and 21C. As shown in FIG. 4A , the chuck driver 4 includes a voltage application unit 41 that applies a voltage between the terminal electrodes 2121a and 2122a via power supply lines L21 and L22, and a current limiting circuit 42 that limits the current flowing between the terminal electrodes 2111a and 2112a, between the terminal electrodes 2121a and 2122a, and between the terminal electrodes 2131a and 2132a when the current reaches a preset current threshold. The electrostatic chuck 1 is disposed in a vacuum chamber 100, for example. The current limiting circuit 42 then limits the current when a discharge begins to occur between the terminal electrodes 2111a and 2112a, between the terminal electrodes 2121a and 2122a, and between the terminal electrodes 2131a and 2132a and the current reaches a preset current threshold. This current threshold is smaller than the discharge initiation current at which the substrate, the object being held, does not fall off. For example, assume that a current of 10 mA flows when a discharge occurs between the terminal electrodes 2111a and 2112a, between the terminal electrodes 2121a and 2122a, or between the terminal electrodes 2131a and 2132a. In this case, the current threshold is set to approximately 3 mA. When a discharge occurs, there is a warning period during which a current of approximately 3 mA flows, which is sufficient to prevent the substrate from falling off, followed by a current of approximately 10 mA, sufficient to cause the discharge and cause the substrate to fall off. This warning period is approximately 1 second. Therefore, in this embodiment, the discharge is prevented from occurring by limiting the current in advance during the warning period before the discharge occurs. The substrate is prevented from falling off by repeatedly increasing the current and then limiting (cutting off) it during the warning period after the current increase begins. As a result, a voltage having a pulse train waveform, such as that shown in Fig. 4B, is applied between terminal electrodes 2111a and 2112a, between terminal electrodes 2121a and 2122a, and between terminal electrodes 2131a and 2132a. Here, voltage value V2 indicates the voltage value at which the held object will not fall off.At this time, currents having a pulse train-like time waveform as shown in FIG. 4C flow between terminal electrodes 2111a and 2112a, between terminal electrodes 2121a and 2122a, and between terminal electrodes 2131a and 2132a. Here, current value I1 indicates the current value at which the held object will not fall off, and current value I2 indicates the current value when the held object is being held. When current value I3 is reached, a discharge occurs and the held object falls off. In FIG. 4C, currents I1 and I2 are current values ​​at which the substrate will not fall off, and current I3 is a current value at which the substrate will fall off. When current I1 is reached within warning period dT2, the current is limited. As a result, discharges occurring between the terminal electrodes 2121a and 2122a and between the terminal electrodes 2131a and 2132a increase the current to a current value I3, causing a voltage drop between the terminal electrodes 2121a and 2122a and between the terminal electrodes 2131a and 2132a. This prevents the substrate from falling off. Here, the voltages V1 and V2 are set to voltages that allow the electrostatic chuck 1 to maintain its ability to hold the object. The chuck driver 4 applies a voltage between the terminal electrodes 2111a and 2112a via the power feed lines L11 and L12. This prevents discharges from occurring between the power feed lines L11 and L12, between L21 and L22, and between L31 and L32.

[0018] Next, a method for manufacturing an electrostatic chuck according to this embodiment will be described with reference to FIGS. 5A to 5D. First, a first insulating substrate 11 and a second insulating substrate 12 are prepared. Then, as shown in FIG. 5A, a mask M is placed on the first surface 11b of the first insulating substrate 11 so as to cover the first surface 11b. A slit H is formed through the mask M in a portion facing the area on the first surface 11b of the first insulating substrate 11 where the conductor pattern 21 is to be formed. Next, a recess formation process is performed in which recesses 11a are formed in the area on the first surface 11b of the first insulating substrate 11 where the conductor pattern 21 is to be formed using dry etching. Here, for example, as shown by arrow AR11 in FIG. 5B, a particle beam source So1 is moved as shown by arrow AR12 while irradiating the particle beam toward the first insulating substrate 11. Furthermore, for example, an Ar particle beam can be used as the particle beam. In this manner, the area on the first surface 11b of the first insulating substrate 11 where the conductor pattern 21 is to be formed is etched.

[0019] Next, a conductor pattern forming process is performed to form the conductor pattern 21 inside the recess 11a of the first insulator substrate 11. Here, as shown in FIG. 5C , for example, two particle beam sources So1 and So2 are used to irradiate the material that will form the conductor pattern 21 onto the inside of the recess 11a of the first insulator substrate 11. A target material TA formed from the material that will form the conductor pattern 21 is fixed to a side of one particle beam source So2, and the other particle beam source So1 irradiates a particle beam toward the target material TA fixed to the particle beam source So2, as shown by arrow AR21, thereby sputtering the target material TA. At this time, the target material TA fixed to the particle beam source So2 is sputtered by the particle beam incident from the particle beam source So1, and the material that will form the conductor pattern 21 is irradiated from the target material TA toward the inside of the recess 11a of the first insulator substrate 11, as shown by arrow AR22. Then, the two particle beam sources So1 and So2 are moved as shown by the arrow AR23, whereby the conductive patterns 21 are formed inside all of the recesses 11a of the first insulating substrate 11.

[0020] Thereafter, an activation process is performed in which the first surface 11b of the first insulator substrate 11 is activated by performing an etching process in which a particle beam is irradiated onto the first surface 11b. Here, for example, with the mask M removed, a particle beam source So1 that emits a particle beam using nitrogen gas is moved toward the first insulator substrate 11 while irradiating the particle beam, similar to the recess formation process described with reference to FIG. 5B. As a result, the first insulator substrate 11 and the entire conductor pattern 21 are etched by the nitrogen particle beam. Next, a radical process is performed in which nitrogen radicals are irradiated toward the first insulator substrate 11.

[0021] Next, as shown by arrow AR3 in FIG. 5D , while maintaining the temperature at 200° C. or less, the second insulator substrate 12 is brought closer to the first surface 11b of the first insulator substrate 11, so that the second surface 12b of the second insulator substrate 12 is brought into surface contact with the first surface 11b of the first insulator substrate 11. Thereafter, a bonding process is performed in which the second insulator substrate 12 is bonded to the first insulator substrate 11 by applying pressure while the first surface 11b of the first insulator substrate 11 and the second surface 12b of the second insulator substrate 12 are in surface contact with each other. This bonding process is performed under reduced pressure. Specifically, the bonding process is performed in an environment with an atmospheric pressure of 1 Pa or more and 100 Pa or less. Furthermore, during this bonding process, the second insulator substrate 12 is hydrophilically bonded to the first insulator substrate 11 via OH groups generated on the first and second surfaces 11b and 12b of the first and second insulator substrates 11 and 12 that are bonded to each other during the cleaning process. In this way, by maintaining the first insulator substrate 11 and the second insulator substrate 12 at a temperature of 200° C. or less, the second insulator substrate 12 is bonded to the first insulator substrate 11 in a solid state.

[0022] In the conductive pattern forming process, if the thickness of layer 9021 of material that forms the base of conductive pattern 21 inside recess 11a is thinner than the depth of recess 11a, as shown in Fig. 6A, a gap S9001 will form between second insulator substrate 12 and recess 11a, as shown in Fig. 6B, resulting in a decrease in strength. In this case, if particles are present between second insulator substrate 12 and the object to be held, a force will be applied to second insulator substrate 12 through the particles in a direction that pushes second insulator substrate 12 into gap S9001 when joining the object to be held, which may cause cracking of second insulator substrate 12. For this reason, it is preferable to form conductive pattern 21 as shown in Fig. 6D by depositing a larger amount of material that forms the base of conductive pattern 21 and then polishing it, as shown in Fig. 6C.

[0023] As described above, in the manufacturing method of the electrostatic chuck 1 according to the present embodiment, in the bonding step subsequent to the conductive pattern forming step, the second insulator substrate 12 is bonded to the first insulator substrate 11 while maintaining the temperature at 200° C. or less, with the second surface 12b of the second insulator substrate 12 in surface contact with the first surface 11b of the first insulator substrate 11. This allows the conductive pattern 21 to be formed from a material with an allowable temperature range of 200° C. or less, thereby increasing the variety of materials for forming the conductive pattern 21.

[0024] In this embodiment, the bonding process is performed under reduced pressure, which prevents gas from entering between the first and second insulating substrates 11 and 12, thereby reducing the occurrence of voids between the first and second insulating substrates 11 and 12.

[0025] In a conventional method, a conductor pattern is formed on a first insulating substrate 11, and then the conductor pattern is sandwiched between the first insulating substrate 11 and the second insulating substrate 12. The conductor pattern is then hot-pressed at a pressure of about 40 tons while maintaining a temperature of about 1100°C to soften the conductor pattern, thereby embedding the conductor pattern between the first insulating substrate 11 and the second insulating substrate 12. However, in this case, if the conductor pattern is a transparent electrode such as ITO, the conductor pattern may be deteriorated if the temperature of the conductor pattern is raised to about 1100°C. Furthermore, hot-pressing may require relatively large-scale equipment. In contrast, in the method for manufacturing an electrostatic chuck according to the present embodiment, the first surface 11b of the first insulating substrate 11 is etched to form a recess 11a, and the conductor pattern 21 is formed inside the recess 11a, thereby preventing the conductor pattern 21 from protruding from the first surface 11b of the first insulating substrate 11 in the thickness direction of the first insulating substrate 11. This eliminates the need to melt the first insulator substrate 11 and the second insulator substrate 12 before welding them together. Therefore, the first insulator substrate 11 and the second insulator substrate 12 can be bonded in a solid state, allowing bonding at a temperature of 700°C or lower to 300°C or lower. Furthermore, the first insulator substrate 11 and the second insulator substrate 12 can be bonded at a relatively low temperature of 200°C or lower under reduced pressure by hydrophilic bonding. Therefore, the method for manufacturing an electrostatic chuck does not require the above-mentioned relatively large-scale equipment, and the first insulator substrate 11 and the second insulator substrate 12 can be bonded at a relatively low temperature, allowing a transparent electrode such as ITO to be used for the conductor pattern 21.

[0026] In the comparative electrostatic chuck shown in FIG. 7A , for example, the distance H11 between the conductive pattern 11021 formed on the first insulator substrate 11 and the substrate W1, which is the object to be held and placed on the side of the second insulator substrate 11012 opposite the conductive pattern 11021, is 0.1 μm to 1.0 μm. In this case, the Coulomb force predominates in attracting the substrate W1. In the comparative electrostatic chuck shown in FIG. 7B , for example, the distance H12 between the conductive pattern 12021 formed on the first insulator substrate 11 and the substrate W1 placed on the side of the second insulator substrate 12012 opposite the conductive pattern 12021, is 2 μm to 5 μm. In this case, the Johnsen-Rahbek force predominates in attracting the substrate W1. This electrostatic chuck holds the object to be held with a virtual electrode formed near the object between the object and the electrostatic chuck. This allows for a large distance between the conductive pattern and the surface, making the electrostatic chuck relatively easy to fabricate. Furthermore, in electrostatic chucks that use the Johnson-Rahbek force to hold a substrate, charges generated within the substrate tend to remain trapped within the substrate when the substrate is released. Even after the substrate is released, the charges trapped within the substrate can cause the substrate to remain stuck to the electrostatic chuck for a long time. In contrast, the electrostatic chuck 1 according to this embodiment uses Coulomb force directly to hold the object without using virtual electrodes, with the distance between the conductive pattern 21 and the surface being 1.0 mm or less, preferably 0.1 mm or less. Therefore, when the object is released from the electrostatic chuck, charges generated within the object quickly dissipate, preventing the object from sticking to the electrostatic chuck. Furthermore, when the electrostatic chuck 1 according to this embodiment holds the object, multiple regions of opposite polarities alternately appear within the object, reflecting the respective arrangements of the multiple electrodes 2111b, 2112b, 2121b, and 2122b. That is, as shown in Fig. 7C, by alternately arranging positive and negative electrode elements 2111b, 2112b, 2121b, and 2122b, the substrate W1 is attracted by utilizing the electric field (dashed line in Fig. 7C) generated between the two electrodes. In addition, the distance between adjacent electrode elements 2111b, 2112b, 2121b, and 2122b is 2.0 mm or less.Therefore, charges generated in multiple regions within the object are easily eliminated by being offset between adjacent regions of opposite polarity. When an operation to release the object is performed, the charges generated within the object are quickly eliminated, preventing the object from adhering to the electrostatic chuck. In other words, while electrostatic chucks that use the Johnsen-Rahbek force to hold a substrate are difficult to eliminate, electrostatic chucks that can thin the dielectric layer between the object and the electrodes 2111b, 2112b, 2121b, and 2122b are advantageous in that they are easily eliminated. The electrostatic chuck 1 according to this embodiment is particularly preferable because it is easy to eliminate charges even between adjacent electrodes 2111b, 2112b, 2121b, and 2122b.

[0027] Furthermore, when the atmosphere around the electrostatic chuck 1 is changed from atmospheric pressure to a high vacuum state or from a high vacuum state to atmospheric pressure, the atmosphere around the electrostatic chuck 1 temporarily becomes an atmosphere of several Pa to several hundred Pa, in which discharge is likely to occur. For this reason, in the electrostatic chuck 1 to which a voltage of several hundred volts to several thousand volts is applied, discharge is likely to occur at the portions of the terminal electrodes 2111a, 2112a, the terminal electrodes 2121a, 2122a, and the terminal electrodes 2131a, 2132a that are exposed to the outside of the electrostatic chuck 1. Once discharge occurs, the voltage applied to the conductive pattern 21 drops, which reduces the chucking force of the electrostatic chuck 1, potentially causing the held object to fall unintentionally. In contrast, the chuck driving unit 4 according to this embodiment includes a voltage application unit 41 that applies a voltage between the terminal electrodes 2121a and 2122a via the power supply lines L21 and L22, and a current limiting circuit 42 that limits the current flowing between the terminal electrodes 2111a and 2112a, between the terminal electrodes 2121a and 2122a, and between the terminal electrodes 2131a and 2132a when the current reaches a preset current threshold, thereby preventing the occurrence of discharge by limiting the current in advance in a warning period before discharge occurs between the terminal electrodes 2111a and 2112a, between the terminal electrodes 2121a and 2122a, and between the terminal electrodes 2131a and 2132a. This makes it possible to maintain the chucking force of the electrostatic chuck 1.

[0028] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, in the recess formation step, recesses 11a may be formed by blasting the regions on the first surface 11b of first insulator substrate 11 where conductor patterns 21 are to be formed. Alternatively, blasting may be performed on the aforementioned regions on the first surface 11b of first insulator substrate 11 where conductor patterns 21 are to be formed, to form recesses 11a of a predetermined depth in the regions on first insulator substrate 11 where conductor patterns 21 are to be formed, and then the inside of recesses 11a in first insulator substrate 11 may be further etched by irradiating it with a particle beam.

[0029] According to this configuration, the depth of the recess 11a can be made deeper than when the recess 11a is formed in the first insulator substrate 11 only by etching, and therefore the thickness of the conductor pattern 21 can be made thicker accordingly.

[0030] In the embodiment, an example has been described in which the recesses 11a are formed by dry etching in the regions on the first surface 11b of the first insulator substrate 11 where the conductor pattern 21 is to be formed in the recess formation step. However, this is not a limitation, and the recesses 11a may also be formed by, for example, wet etching. Furthermore, in the embodiment, an example has been described in which an Ar particle beam is used, but this is not a limitation, and the recesses 11a may also be formed by reactive ion etching using a reactive gas such as SF6 in the recess formation step.

[0031] In the embodiment, an example has been described in which the activation treatment step involves performing an etching process by irradiating the first surface 11b of the first insulator substrate 11 with a particle beam. However, this is not limiting. For example, the activation treatment step may involve an etching process in which the first surface 11b of the first insulator substrate 11 is exposed to plasma. In this case, the entire first insulator substrate 11 and the conductive pattern 21 are etched by the plasma. Note that the activation treatment step may involve an etching process in which both the first surface 11b of the first insulator substrate 11 and the second surface 12b of the second insulator substrate 12 are exposed to plasma. Alternatively, the activation treatment step may involve an etching process in which only the second surface 12b of the second insulator substrate 12 is exposed to plasma. In this case, reactive ion etching may be performed by exposing at least one of the first surface 11b of the first insulator substrate 11 and the second surface 12b of the second insulator substrate 12 to nitrogen-containing plasma. Furthermore, in the activation treatment step, before the etching treatment described above, reactive ion etching may be performed by exposing at least one of the layers to be etched to a plasma containing oxygen.

[0032] In the embodiment, an example has been described in which activation is performed by etching only the first surface 11b side of the first insulator substrate 11 in the activation treatment step. However, this is not limiting, and in the activation treatment step, etching treatment in which a particle beam is irradiated may be performed on both the first surface 11b side of the first insulator substrate 11 and the second surface 12b side of the second insulator substrate 12. Alternatively, in the activation treatment step, etching treatment in which a particle beam is irradiated may be performed on only the second surface 12b side of the second insulator substrate 12.

[0033] In the embodiment, an example has been described in which, in the activation treatment step, an etching treatment is performed by irradiating a particle beam using nitrogen gas onto the first surface 11b of the first insulator substrate 11 and the second surface 12b of the second insulator substrate 12, and then a radical treatment is performed by irradiating the first surface 11b and the second surface 12b with nitrogen radicals. However, this is not limiting, and for example, in the activation treatment step, the second insulator substrate 12 may be bonded to the first insulator substrate 11 directly after the etching treatment without performing the radical treatment described above.

[0034] In an embodiment, for example, as in the electrostatic chuck 2001 shown in FIG. 8 , the second insulator substrate 12 may be formed of transparent glass and have a ceramic material region 2015 disposed on the second insulator substrate 12 except for its peripheral portion. Note that in FIG. 8 , the same components as those in the embodiment are denoted by the same reference numerals as in FIG. 1 . Here, the ceramic material may be a ceramic containing a metal element, such as AlN, Al2O3, or yttria. Conductor patterns 2021B and 2021A are embedded in the ceramic material region 2016 and the outer periphery of the ceramic material region 2016 on the second insulator substrate 12, respectively. Furthermore, a heater 2016 is embedded in the ceramic material region 2016 on the side opposite the exposed surface of the ceramic material region 2016 relative to the conductor pattern 2021B. Because ceramics have a higher thermal conductivity than glass, it is preferable to embed the heater 2016 in the ceramic material region 2016 from the viewpoint of efficiently heating the object to be held.

[0035] The electrostatic chuck 2001 is provided on a stage 2401 and a head 2402 of a bonding apparatus. The stage 2401 and the head 2402 each include a pressing mechanism 51 provided in the center of the stage 2401 and the head 2402. The pressing mechanism 51 includes a pressing unit 51a that can be moved toward and away from the stage 2401 and the head 2402 through a through hole 1a provided in the center of the electrostatic chuck 2001, and a pressing driver 51b that drives the pressing unit 51a. The ceramic material region 2015 of the electrostatic chuck 2001 may be disposed inside the intersection of an optical axis LJ1 of an imaging unit 2051 that measures the amount of positional deviation of substrates (not shown) held by the stage 2401 and the head 2402 in the electrostatic chuck 2001, and an optical axis LJ2 of a laser rangefinder 2052 that measures the distance between the substrates.

[0036] In the electrostatic chuck manufacturing method according to this modified example, the second insulator substrate 12 has an opening in the center, and the second insulator substrate 12 and the first insulator substrate 11 are joined together by the joining process described in the embodiment to form a structure in which the conductor pattern 21 is embedded between the first insulator substrate 11 and the second insulator substrate 12. Thereafter, a ceramic material region forming process is performed in which the ceramic material region 2015 is formed by repeatedly forming a conductor pattern that will serve as the base of the heater 2016 in the opening in the center of the second insulator substrate 12, spraying a ceramic material containing a metal element, forming the conductor pattern 21, and spraying the ceramic material.

[0037] According to this configuration, the provision of the ceramic material region 2015 can prevent the substrate from becoming difficult to peel off from the electrostatic chuck 2001 when the substrate is released from the electrostatic chuck 2001. Furthermore, since the ceramic material region 2015 is formed by thermal spraying of a ceramic material, minute irregularities are formed on the surface of the ceramic material region 2015. This allows charge generated at the contact interface between the substrate and the ceramic material region 2015 due to sliding friction between them when the substrate is held by the electrostatic chuck 2001 to be easily neutralized by gas discharge occurring in a microgap formed by the minute irregularities. Therefore, when the substrate is released from the electrostatic chuck 2001, the substrate can be prevented from becoming difficult to peel off from the electrostatic chuck 2001 due to charge generated at the contact interface between the substrate and the ceramic material region 2015. Furthermore, the formation of the minute irregularities reduces the degree of adhesion of the substrate to the ceramic material region 2015, making it easier for the substrate to peel off from the ceramic region 2015.

[0038] Furthermore, with this configuration, the amount of polishing of the second insulator substrate 12 after the ceramic material is sprayed onto the second insulator substrate 12 is small. Therefore, a thin second insulator substrate 12 can be used as the second insulator substrate 12 before the thermal spraying. Therefore, after preparing the second insulator substrate 12, the amount of polishing in the polishing process of the second insulator substrate 12 can be reduced, and the processing time can be shortened.

[0039] The glass forming the second insulator substrate 12 has a relatively high insulation resistance, and therefore, when charged, the charge does not easily escape. In contrast, according to the present configuration, the ceramic material forming the ceramic material region 2015 can have its insulation resistance adjusted by adjusting the content of metal elements contained therein. Furthermore, the insulation resistance of the ceramic material region 2015 can be adjusted to be optimal at the temperature during use. Therefore, a conductor pattern (not shown) for performing a heating function can be embedded in the second insulator substrate 12, along with the conductor pattern 21 for performing the function of the electrostatic chuck 1.

[0040] The electrostatic chuck 1 according to the embodiment may include a gas discharge unit that discharges gas between the substrate and the second insulator substrate 12 when the substrate is released from the electrostatic chuck 1. Argon gas is most preferable as the discharged gas, but nitrogen gas or helium gas may also be used. This facilitates neutralization of charges generated when the electrostatic chuck 1 is driven or charges generated at the contact interface between the substrate and the surface of the second insulator substrate 12 due to sliding friction between the two when the substrate is held by the electrostatic chuck 1 by discharging into the discharged gas. Therefore, when the substrate is released from the electrostatic chuck 1, it is possible to prevent the substrate from being difficult to remove from the electrostatic chuck 1 due to charges generated at the contact interface between the substrate and the second insulator substrate 12.

[0041] In the electrostatic chuck 1 according to the embodiment, a third surface of the second insulator substrate 12 opposite to the first insulator substrate 11 side may be roughened, and a gas discharge unit may be provided that discharges gas between the third surface and the substrate when the object to be held is released from the third surface side of the second insulator substrate 12. Here, the surface roughness of the roughened third surface 12c is 0.1 μm to 1 mm in arithmetic mean roughness.

[0042] The electrostatic chuck 1 according to the embodiment may include fine grooves formed on the entire third surface of the second insulator substrate 12, and a gas discharge unit that discharges gas into the grooves when the held object is released while a substrate is held on the third surface side of the second insulator substrate 12. Here, the held object is, for example, a substrate. In the first region A1 of the electrostatic chuck according to this modification, a groove 4031d is formed, part of which extends radially from the center of the third surface 12c toward the periphery of the third surface 12c, as shown in FIG. 9A . A gas discharge hole 4031c connected to a gas supply unit 4033 is provided in part of the groove 4031d. The groove 4031d has a portion that extends along the extension direction of each of the plurality of electrodes 2121b and 2122b. The groove 4031d is provided between the plurality of electrode elements 2121b electrically connected to the terminal electrode 2121a and the plurality of electrode elements 2122b connected to the terminal electrode 2122a. In the second region A2, as shown in FIG. 9B, grooves 4032d are formed, each having a portion extending radially from the center of the third surface 12c of the second insulator substrate 12 toward the periphery of the third surface 12c. A gas discharge hole 4032c connected to the gas supply unit 4033 is provided in part of the groove 4032d. The groove 4032d has a portion extending in the same direction as the plurality of electrode elements 2131b, 2132b. The groove 4032d is provided between the plurality of electrode elements 2131b electrically connected to the terminal electrode 2131a and the plurality of electrode elements 2132b connected to the terminal electrode 2132a. The grooves in the second region A2 may have a spiral shape extending from the center of the second region A2 outward, which is preferable because it reduces the number of gas discharge holes.

[0043] Furthermore, if the distance between the conductive pattern 21 and the surface is 1.0 mm or less or 0.1 mm or less, the depth of the grooves 4031d, 4032d is preferably 0.5 mm or less or 0.05 mm or less. In particular, when the depth of the grooves 4031d, 4032d is 0.5 mm or less or 0.05 mm or less, it is preferable that the size of the gas molecules used to fill the grooves is small, such as a gas containing helium. Furthermore, when the surface roughness Ra of the third surface is several tens of μm or less or 1 μm or less, it is also preferable that the size of the gas molecules used to fill the gap between the third surface and the object to be held is small, such as a gas containing helium. In this case, helium thoroughly penetrates into the minute gaps formed between the object to be held and the third surface, making it easier for the object to be released from the electrostatic chuck 1.

[0044] In the embodiment, when holding an object to be held, the voltage application unit 41 of the chuck driving unit 4 may apply an alternating voltage with a frequency of 2 Hz or more whose amplitude gradually increases over time between the terminal electrodes 2121a and 2122a and between the terminal electrodes 2131a and 2132a, as shown in FIG. 10A . This allows residual charge on the electrostatic chuck 1 to be removed before holding the object. In particular, repeated holding of objects causes residual charge to accumulate on the electrostatic chuck 1. Therefore, in this modification, the residual charge accumulated on the surface of the electrostatic chuck 1 can be reset before holding the object. Furthermore, when releasing the object to be held, the voltage application unit 41 may apply an alternating voltage with a frequency of 2 Hz or more whose amplitude gradually decreases over time between the terminal electrodes 2121a and 2122a and between the terminal electrodes 2131a and 2132a, as shown in FIG. 10B . This makes it possible to remove residual charge from the electrostatic chuck 1 while the object is held thereon, so that the object can be easily removed from the electrostatic chuck 1.

[0045] Furthermore, a manufacturing method of an electrostatic chuck according to the present invention may include a conductor pattern forming step of forming a transparent conductor pattern made of ITO on a first surface side in the thickness direction of a first insulator substrate, a resin applying step of applying a transparent ultraviolet-curable resin material to the first surface side of the first insulator substrate, and, after the resin applying step, a bonding step of bonding a second insulator substrate to the first insulator substrate while bringing a second surface side of the second insulator substrate, which is to be bonded to the first insulator substrate in the thickness direction, into surface contact with the first surface side of the first insulator substrate. In this case, for example, as shown in FIG. 11 , an electrostatic chuck 3001 can be manufactured, which includes a first insulator substrate 11, a conductor pattern 3021 made of ITO on one surface side 11b in the thickness direction of the first insulator substrate 11, a transparent resin layer 3013 that covers a portion of the first insulator substrate 11 on the first surface 11b side except for the conductor pattern 3021, and a second insulator substrate 12 bonded to cover the resin layer 3013 and the conductor pattern 3021.

[0046] In this modification, the distance between conductor pattern 3021 and the surface of second insulator substrate 12 opposite to conductor pattern 3021 may be 1.0 mm or less. Furthermore, when conductor pattern 3021 includes a first terminal electrode, a second terminal electrode, a plurality of first electrode elements electrically connected to the first terminal electrode, and a plurality of second electrode elements electrically connected to the second terminal electrode, and the plurality of first electrode elements and the plurality of second electrode elements are formed so as to be alternately arranged along a predetermined first direction, the distance between two adjacent first electrode elements or two adjacent second electrode elements may be 2.0 mm or less.

[0047] Furthermore, in this modified example, the third surface 12c of the second insulator substrate 12 opposite the first insulator substrate 11 side may be roughened, and may be provided with a gas discharge section that discharges gas between the third surface 12c and the object to be held when the object to be held is held on the third surface 12c side of the second insulator substrate 12.

[0048] Further, the third surface 12c of the second insulator substrate 12 may have grooves formed in a first region A1 facing the periphery of the disk-shaped substrate, which is the object to be held, and in a second region A2 inside the first region A1, and the third surface 12c may be provided with a gas discharge unit that discharges gas into the grooves while the object to be held is held on the third surface 12c side of the second insulator substrate 12. These configurations also provide the same effects as the electrostatic chuck 1 having the metal conductor pattern 21 described in the embodiment.

[0049] However, ITO deteriorates when heated to temperatures above 100°C or above 150°C. In contrast, with this configuration, the first insulating substrate and the second insulating substrate are bonded via an ultraviolet-curable resin material, so bonding can be achieved at temperatures below 100°C or below 150°C. This prevents the ITO from deteriorating.

[0050] The embodiment or each of the above-described modified examples may further include a pressing mechanism that presses the center of a substrate, which is a held object held by the insulating substrate of the electrostatic chuck, at the center of the insulating substrate of the electrostatic chuck. In this case, for example, as shown in FIG. 12A , with substrates W1 and W2 held by stage 5401 and head 5402, respectively, the substrate W2 is first released from the holding position in a second region inside a first region facing the periphery of the substrate W2. Next, as shown by arrow AR51 in FIG. 12B , the pressing mechanism 5440 presses the center of the substrate W2, deflecting the center of the substrate W2 so that it protrudes away from the insulating substrate of the electrostatic chuck provided on head 5402 compared to the periphery of the substrate W2. In this state, the center of the substrate W2 is brought into contact with the center of substrate W1, which is a joining object to be joined to the substrate W2, as shown by arrow AR52 in FIG. 12C . As a result, the joining of substrates W2 and W1 proceeds from the center toward the periphery. Then, as shown in FIG. 12D, the substrates W1 and W2 are bonded to each other over their entire surfaces.

[0051] However, if the substrates W1 and W2 are difficult to separate from the electrostatic chuck, distortion is likely to occur in the substrates W1 and W2. In contrast, with this configuration, the substrates W1 and W2 naturally separate from the electrostatic chuck, so the substrates W1 and W2 can be bonded to each other with high precision without distortion.

[0052] In an embodiment, the electrostatic chuck may include a protective layer covering at least a third surface of the second insulator substrate 12 opposite the second surface 12b in the thickness direction of the second insulator substrate 12, i.e., a portion that contacts a substrate to be held. Here, the protective layer may be formed from diamond-like carbon (hereinafter referred to as "DLC") or a resin. Also, polyimide or polytetrafluoroethylene can be used as the resin. Furthermore, when the protective layer is formed from DLC, the thickness of the protective layer can be set to approximately 500 nm. Furthermore, when the protective layer is formed from a resin, the thickness of the protective layer can be set to approximately 1.5 μm.

[0053] Here, a method for manufacturing an electrostatic chuck according to this modified example will be described. First, as described in the embodiment, the first insulating substrate 11 and the second insulating substrate 12 are prepared, and then the recess forming step, conductor pattern forming step, activation treatment step, and bonding step are performed. Next, a protective layer forming step is performed to form a protective layer on at least the third surface of the second insulating substrate 12. Here, if the protective layer is made of DLC, the DLC is deposited on the third surface of the second insulating substrate 12 by ion deposition using plasma containing ions of a hydrocarbon gas such as methane or acetylene in the protective layer forming step.

[0054] For an example of an electrostatic chuck having a protective layer of approximately 500 nm thickness formed from DLC according to this modification, the Vickers hardness of the protective layer was measured by nanoindentation and found to be 22 GPa, which was higher than the Vickers hardness of 8.6 to 9.8 for synthetic quartz, which can be used as the material for the second insulator substrate 12. This indicates that for an electrostatic chuck having a second insulator substrate 12 made from synthetic quartz, providing a protective layer made from DLC to cover the portion of the electrostatic chuck that contacts the substrate can increase the hardness of the portion that contacts the substrate, thereby suppressing damage to the contact portion. Furthermore, as shown in FIG. 13A , the transmission spectrum of light transmitted through the second insulator substrate 12 of the example of an electrostatic chuck having a protective layer made from DLC according to this modification in the thickness direction showed a transmittance of approximately 73% in the wavelength band of light transmitted through a Si substrate, i.e., the wavelength band of 1100 nm to 1200 nm. This shows that when an electrostatic chuck equipped with a protective layer made of DLC is used, it is possible to image an alignment mark provided on a substrate held by the electrostatic chuck using light that passes through the Si substrate.

[0055] 13B , the transmission spectra of light transmitted in the thickness direction of the second insulator substrate 12 of each of the two examples of electrostatic chucks having a protective layer made of polyimide and having a thickness of about 1.5 μm showed a transmittance of about 90% in the wavelength band of light transmitted through a Si substrate, i.e., the wavelength band of 1100 nm to 1200 nm, as shown by curves S70 and S71. This shows that even when an electrostatic chuck having a protective layer made of resin is used, an alignment mark provided on a substrate held by the electrostatic chuck can be imaged using light transmitted through the Si substrate.

[0056] According to this configuration, when the protective layer is made of DLC, alignment marks on a substrate held by an electrostatic chuck can be imaged using light transmitted through the Si substrate, while suppressing damage to the contact area with the substrate, thereby suppressing damage to the substrate due to damage to the contact area. Furthermore, when the protective layer is made of an elastically deformable resin such as polyimide, the impact on the substrate when the electrostatic chuck holds the substrate is mitigated, thereby suppressing damage to the substrate. Furthermore, the surface of the protective layer made of DLC or resin is formed with minute irregularities. This facilitates neutralization of electric charges generated at the contact interface between the substrate and the protective layer due to sliding friction when the substrate is held by the electrostatic chuck by gas discharges occurring in the microgaps formed by the minute irregularities. Therefore, when the substrate is released from the electrostatic chuck, it is possible to suppress the substrate from being difficult to remove from the electrostatic chuck due to electric charges generated at the contact interface between the substrate and the protective layer.

[0057] In an embodiment, at least the second insulating substrate 12 may have an inclined surface formed around the entire periphery of the third surface side opposite the second surface 12b side in the thickness direction of the second insulating substrate 12, the inclined surface being inclined so that the further it is positioned from the third surface toward the first insulating substrate 11, the further away it is from the central axis extending in the thickness direction of the second insulating substrate 12.

[0058] 14 , for example, an electrostatic chuck 6001 according to this modification includes a first insulator substrate 6011, a conductor pattern (not shown) formed of ITO on a first surface 6011b of the first insulator substrate 6011, a transparent resin layer 6013 covering the first surface 6011b of the first insulator substrate 6011 except for the conductor pattern, and a second insulator substrate 6012 bonded to cover the resin layer 6013 and the conductor pattern. A through-hole 6001a is formed in the center of the electrostatic chuck 6001, through which a pressing member (not shown) that presses the center of a substrate held by the electrostatic chuck 6001 is inserted. The second insulator substrate 6012 has an inclined surface 6012d formed along the entire periphery on the third surface 6012c side of the second insulator substrate 6012. The inclined surface 6012d inclines so as to move away from the central axis J6 extending in the thickness direction of the second insulator substrate 6012 as it moves from the third surface 6012c toward the first insulator substrate 6011. Furthermore, the second insulator substrate 6012 has an inclined surface 6012e formed along the entire periphery on the third surface 6012c side of the through hole 6001a of the second insulator substrate 6012. The inclined surface 6012e inclines so as to move closer to the central axis J6 as it moves from the third surface 6012c toward the first insulator substrate 6011. Furthermore, the first insulator substrate 6011 has an inclined surface 6011d formed along the entire periphery of the first insulator substrate 6011 on the first surface 6011b side of the first insulator substrate 6011. The inclined surface 6011d is inclined away from the central axis J6 as it moves from the first surface 6011b toward a fourth surface 6011f opposite the first surface 6011b in the thickness direction of the first insulator substrate 6011. The first insulator substrate 6011 has an inclined surface 6011e formed along the entire periphery of the through hole 6001a on the first surface 6011b side of the first insulator substrate 6011. The inclined surfaces 6011d and 6011e of the first insulator substrate 6011 and the inclined surfaces 6012d and 6012e of the second insulator substrate 6012 are polished to a mirror finish.

[0059] Here, a manufacturing method of an electrostatic chuck according to this modification is described. First, a conductor pattern forming process is performed to form the aforementioned conductor pattern on the first surface 6011b of the first insulator substrate 6011. Next, a resin application process is performed to apply a resin material to the first surface 6011b of the first insulator substrate 6011. After that, a bonding process is performed to bond the second insulator substrate 6012 to the first insulator substrate 6011 while the second surface 6012b of the second insulator substrate 6012 is brought into surface contact with the first surface 6011b of the first insulator substrate 6011. Next, a chamfering process is performed to chamfer the entire periphery of the third surface 6012c of the second insulator substrate 6012. As a result, as shown in FIG. 15A , an inclined surface 6012d is formed along the entire periphery of the third surface 6012c of the second insulator substrate 6012, which is inclined so that the farther it is from the third surface 6012c toward the first insulator substrate 6011, the farther it is from the central axis J6. The first insulator substrate 6011 has the inclined surface 6011d. In this chamfering process, the inclined surface 6012e is formed over the entire periphery of the through-hole 6001a on the third surface 6012c side of the second insulator substrate 6012, and the inclined surface 6011e is formed over the entire periphery of the through-hole 6001a on the first surface 6011b side of the first insulator substrate 6011. Next, a first polishing process is performed in which the inclined surfaces 6011d, 6011e, 6012d, and 6012e are polished to a mirror finish. Thereafter, as shown in FIG. 15B , a second polishing process is performed in which the thickness of the second insulator substrate 6012 is reduced by the polishing allowance by polishing the third surface 6012c side of the second insulator substrate 6012.

[0060] According to this configuration, the peripheral portions of the first insulator substrate 6011 and the second insulator substrate 6012 are chamfered, which reduces stress concentration on the peripheral portions of the first insulator substrate 6011 and the second insulator substrate 6012 when tensile stress is applied to the entire electrostatic chuck 6001. This reduces damage to the peripheral portions of the first insulator substrate 6011 and the second insulator substrate 6012 when tensile stress is applied to the entire electrostatic chuck 6001. Furthermore, according to this configuration, the inclined surfaces 6011d and 6011e of the first insulator substrate 6011 and the inclined surfaces 6012d and 6012e of the second insulator substrate 6012 are polished to a mirror finish. This reduces the occurrence of microcracks in the first insulator substrate 6011 and the second insulator substrate 6012 when the electrostatic chuck 6001 is manufactured.

[0061] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to illustrate the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of the present invention.

[0062] This application is based on Japanese Patent Application No. 2023-139776, filed on August 30, 2023. The entire specification, claims, and drawings of Japanese Patent Application No. 2023-139776 are incorporated herein by reference. [Industrial Applicability]

[0063] The present invention is suitable for a bonding apparatus having a function of capturing an image of an alignment mark of a substrate from the side opposite to the substrate side in an electrostatic check, for example, with the substrate chucked by an electrostatic chuck. [Explanation of symbols]

[0064] 1, 3001, 6001: electrostatic chuck, 1a, 6001a: through hole, 4: chuck drive unit, 11, 6011: first insulator substrate, 11a: recess, 11b, 6011b: first surface, 12, 6012: second insulator substrate, 12b, 6012b: second surface, 21, 21A, 21B, 21C, 3021: conductor pattern, 51: pressing mechanism, 51a: pressing unit, 51b: pressing drive unit, 2015: ceramic material region, 2051: imaging unit, 2052: laser range finder, 2111a, 2112a, 2121a, 2122a, 2131a, 2132a: terminal Electrode, 2111aa, 2112aa, 2121aa, 2122aa: Connecting part, 2111ab, 2112ab, 2121ab, 2122ab: Bent part, 2111b, 2112b, 2121b, 2122b, 2131b, 2132b: Electrode, 2401: Stage, 2 402: Head, 3013, 6013: Resin layer, 6011d, 6011e, 6012d, 6012e: Inclined surface, 6013c: Third surface, A1: First region, A2: Second region, A11, A12: Sub-annular region, H: Slit, I: Joint interface, So1, So2: Particle beam source

Claims

1. a recess forming step of forming a recess in a region on the first surface side of the first insulating substrate in a thickness direction where a conductor pattern is to be formed; a conductor pattern forming step of forming the conductor pattern inside the recess; a joining step of joining the second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be joined to the first insulator substrate in a thickness direction of the second insulator substrate is brought into surface contact with the first surface side of the first insulator substrate, In the bonding step, the second insulator substrate is bonded to the first insulator substrate while maintaining the temperature of the second insulator substrate at 700° C. or less. Electrostatic chuck manufacturing method.

2. In the bonding step, the second insulating substrate is bonded to the first insulating substrate in a solid state. The method for manufacturing an electrostatic chuck according to claim 1 .

3. The method further includes, before the bonding step, an activation treatment step of activating at least one of the first surface side of the first insulator substrate and the second surface side of the second insulator substrate.

3. The method for manufacturing an electrostatic chuck according to claim 1.

4. In the bonding step, the second insulating substrate is bonded to the first insulating substrate while maintaining the temperature of the second insulating substrate at 200° C. or less. The method for manufacturing an electrostatic chuck according to claim 3 .

5. In the bonding step, the second insulating substrate is bonded to the first insulating substrate in a hydrophilic manner. The method for manufacturing an electrostatic chuck according to claim 3 .

6. In the activation treatment step, at least one of the first surface side of the first insulator substrate and the second surface side of the second insulator substrate is exposed to plasma. The method for manufacturing an electrostatic chuck according to claim 5 .

7. In the activation treatment step, a particle beam is irradiated onto at least one of the first surface side of the first insulator substrate and the second surface side of the second insulator substrate. The method for manufacturing an electrostatic chuck according to claim 5 .

8. The bonding step is carried out under reduced pressure.

3. The method for manufacturing an electrostatic chuck according to claim 1.

9. A recess forming step of forming a recess in a region where a conductor pattern is to be formed on a first surface side in the thickness direction of a first insulating substrate; a conductor pattern forming step of forming the conductor pattern inside the recess; a joining step of joining the second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be joined to the first insulator substrate in a thickness direction of the second insulator substrate is brought into surface contact with the first surface side of the first insulator substrate, The conductive pattern is made of ITO, ZnO, TiO ２ and graphene, Electrostatic chuck manufacturing method.

10. a ceramic material region forming step of forming a ceramic material region from a ceramic material on at least one of the first insulator substrate and the second insulator substrate; 10. The method for manufacturing an electrostatic chuck according to claim 1, 2, or 9.

11. The method further includes a protective layer forming step of forming a protective layer on at least a third surface of the second insulator substrate opposite to the second surface in the thickness direction of the second insulator substrate.

10. The method for manufacturing an electrostatic chuck according to claim 1, 2, or 9.

12. the protective layer is formed from diamond-like carbon or resin; The method for manufacturing an electrostatic chuck according to claim 11.

13. a chamfering process after the bonding process, in which an entire peripheral portion of at least a third surface side of the second insulator substrate opposite to the second surface side in the thickness direction of the second insulator substrate is chamfered to form an inclined surface that is inclined so as to become more distant from a central axis extending in the thickness direction of the second insulator substrate as it moves from the third surface toward the second insulator substrate, all over the peripheral portion of the third surface side of the second insulator substrate; a first polishing step of polishing the inclined surface after the chamfering step; a second polishing step of polishing the third surface side of the second insulator substrate after the first polishing step, 10. The method for manufacturing an electrostatic chuck according to claim 1, 2, or 9.

14. A recess forming step of forming a recess in a region where a conductor pattern is to be formed on a first surface side in the thickness direction of a first insulating substrate; a conductor pattern forming step of forming the conductor pattern inside the recess; a joining step of joining the second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be joined to the first insulator substrate in a thickness direction of the second insulator substrate is in surface contact with the first surface side of the first insulator substrate after the conductor pattern forming step; a ceramic material region forming step of forming a ceramic material region from a ceramic material on at least one of the first insulator substrate and the second insulator substrate, In the ceramic material region forming step, the ceramic material region is formed by thermally spraying a ceramic material onto at least one of the first insulator substrate and the second insulator substrate. Electrostatic chuck manufacturing method.

15. a first insulating substrate having a recess formed on a first surface side in a thickness direction; a conductor pattern formed inside the recess; a second insulating substrate that is bonded to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and that forms a bonding interface between a second surface side in a thickness direction of the first insulating substrate and the first surface side of the first insulating substrate and the conductor pattern; the second insulating substrate has a ceramic material region formed from a ceramic material and arranged so as to be exposed at least on a side of the second insulating substrate opposite to the first insulating substrate side; The ceramic material contains a metal element. Electrostatic chuck.

16. a first insulating substrate having a recess formed on a first surface side in a thickness direction; a conductor pattern formed inside the recess; a second insulator substrate bonded to the first insulator substrate in a solid state so as to cover the entire first surface side of the first insulator substrate, the second insulating substrate has a ceramic material region formed from a ceramic material and arranged so as to be exposed at least on a side of the second insulating substrate opposite to the first insulating substrate side; The ceramic material contains a metal element. Electrostatic chuck.

17. a distance between the conductive pattern and the surface of the second insulating substrate opposite to the conductive pattern side is 1.0 mm or less; 17. The electrostatic chuck according to claim 15 or 16.

18. the conductor pattern includes a first terminal electrode, a second terminal electrode, a plurality of first electrodes electrically connected to the first terminal electrode, and a plurality of second electrodes electrically connected to the second terminal electrode, and the plurality of first electrodes and the plurality of second electrodes are formed inside the recess so as to be alternately arranged along a predetermined first direction; 17. The electrostatic chuck according to claim 15 or 16.

19. The distance between two adjacent first electrode elements or two adjacent second electrode elements is 2.0 mm or less.

20. The electrostatic chuck of claim 18.

20. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulating substrate that is bonded to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and that forms a bonding interface between a second surface side in a thickness direction of the first insulating substrate and the first surface side of the first insulating substrate and the conductor pattern; the conductor pattern includes a first terminal electrode and a second terminal electrode, a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode; a current limiting circuit that limits a current flowing between the first terminal electrode and the second terminal electrode when the current reaches a preset current threshold; The current threshold is smaller than the discharge start current at which the held object does not fall off. Electrostatic chuck.

21. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulator substrate bonded to the first insulator substrate in a solid state so as to cover the entire first surface side of the first insulator substrate, the conductor pattern includes a first terminal electrode and a second terminal electrode, a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode; a current limiting circuit that limits a current flowing between the first terminal electrode and the second terminal electrode when the current reaches a preset current threshold; The current threshold is smaller than the discharge start current at which the held object does not fall off. Electrostatic chuck.

22. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulating substrate that is bonded to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and that forms a bonding interface between a second surface side in a thickness direction of the first insulating substrate and the first surface side of the first insulating substrate and the conductor pattern; The conductive pattern is made of ITO, ZnO, TiO ２ and graphene, Electrostatic chuck.

23. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulator substrate bonded to the first insulator substrate in a solid state so as to cover the entire first surface side of the first insulator substrate, The conductive pattern is made of ITO, ZnO, TiO ２ and graphene, Electrostatic chuck.

24. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulating substrate that is bonded to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and that forms a bonding interface between a second surface side in a thickness direction of the first insulating substrate and the first surface side of the first insulating substrate and the conductor pattern; The conductor pattern is a transparent electrode. Electrostatic chuck.

25. A first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; a second insulator substrate bonded to the first insulator substrate in a solid state so as to cover the entire first surface side of the first insulator substrate, The conductor pattern is a transparent electrode. Electrostatic chuck.

26. the second insulating substrate is transparent; 26. The electrostatic chuck according to any one of claims 15, 16, and 20 to 25.

27. The ceramic material is AlN, Al ２ O ３ or yttria, 17. The electrostatic chuck according to claim 15 or 16.

28. a protective layer covering a third surface of the second insulating substrate opposite to a second surface bonded to the first insulating substrate in at least a thickness direction of the second insulating substrate; 26. The electrostatic chuck according to any one of claims 15, 16, and 20 to 25.

29. the protective layer is formed from diamond-like carbon or resin; 29. The electrostatic chuck of claim 28.

30. an inclined surface is formed on at least the second insulating substrate along the entire periphery of a third surface side opposite to a second surface side joined to the first insulating substrate in the thickness direction of the second insulating substrate, the inclined surface being inclined so as to move away from a central axis extending in the thickness direction of the second insulating substrate as it moves from the third surface toward the second insulating substrate; 26. The electrostatic chuck according to any one of claims 15, 16, and 20 to 25.

31. a third surface of the second insulating substrate opposite to the first insulating substrate side is roughened; a gas discharge unit configured to discharge gas between the third surface and the object to be held while the object is held on the third surface side of the second insulating substrate, 26. The electrostatic chuck according to any one of claims 15, 16, and 20 to 25.

32. A third surface of the second insulating substrate opposite to the first insulating substrate side includes a first region facing a periphery of the object to be held in a state in which the object is held on the third surface side of the second insulating substrate, and a second region inside the first region, and a groove is formed in at least the second region, a gas discharge unit that discharges gas into the groove while the object to be held is held on the third surface side of the second insulator substrate, 26. The electrostatic chuck according to any one of claims 15, 16, and 20 to 25.

33. The gas includes at least one of argon, nitrogen, and helium.

32. The electrostatic chuck of claim 31.

34. an insulating substrate; a conductor pattern embedded in the insulating substrate and including a first terminal electrode and a second terminal electrode; a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode; a current limiting circuit that limits a current flowing between the first terminal electrode and the second terminal electrode when the current reaches a preset current threshold; The current threshold is smaller than the discharge start current at which the held object does not fall off. Electrostatic chuck.

35. an insulating substrate; a conductor pattern embedded in the insulating substrate and including a first terminal electrode and a second terminal electrode; a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode, When releasing the held object, the voltage application unit applies an alternating voltage having a frequency of 2 Hz or more and whose amplitude gradually decreases over time between the first terminal electrode and the second terminal electrode. Electrostatic chuck.

36. a pressing mechanism that presses a part of the object to be held on the insulating substrate at the center of the insulating substrate, After releasing the hold of the object to be held in a second region inside the first region facing the periphery of the object to be held, the pressing mechanism presses the center of the object to be held, causing the center of the object to bend so that it protrudes in a direction away from the insulating substrate compared to the periphery of the object to be held, and in this state, the center of the object to be held is brought into contact with the center of an object to be joined to the object to be joined, thereby advancing the joining of the object to be held and the object to be joined.

36. The electrostatic chuck of claim 35.

37. an insulating substrate; a conductor pattern embedded in the insulating substrate and including a first terminal electrode and a second terminal electrode; a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode, When holding the object to be held, the voltage application unit applies an alternating voltage having a frequency of 2 Hz or more, the amplitude of which gradually increases over time, between the first terminal electrode and the second terminal electrode, and then holds the object to be held. Electrostatic chuck.

38. a conductor pattern forming step of forming a conductor pattern made of ITO on a first surface side in a thickness direction of the first insulating substrate; a resin application step of applying an ultraviolet curable resin material to the first surface side of the first insulating substrate; and a joining step of joining the second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be joined to the first insulator substrate in a thickness direction of the second insulator substrate is brought into surface contact with the first surface side of the first insulator substrate, Electrostatic chuck manufacturing method.

39. a first insulating substrate; a conductor pattern made of a transparent conductive material formed on a first surface side in a thickness direction of the first insulating substrate; a resin layer formed from an ultraviolet curable resin material and interposed in an area of ​​the first surface side of the first insulating substrate excluding the conductor pattern; a second insulating substrate disposed so as to cover the conductor pattern and the resin layer, Electrostatic chuck.

Images