Method for manufacturing electrostatic chuck, 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

Electrostatic chuck manufacturing method and electrostatic chuck

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

[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 therebetween to produce a sintered ceramic 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.

[0003] Japanese Patent Application Laid-Open No. 2012-216816

[0004] However, in the method for manufacturing 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 employ 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.

[0006] In order to achieve the above object, the electrostatic chuck manufacturing method according to the present invention 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 conductor pattern is to be formed; a conductor pattern forming step of forming the conductor pattern inside the recess; and a bonding step of, after the conductor pattern forming step, bonding the second insulating substrate to the first insulating substrate in a state in which a second surface side of the second insulating substrate, which is to be bonded to the first insulating substrate in the thickness direction, is in surface contact with the first surface side of the first insulating substrate.

[0007] From another perspective, an 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 conductive pattern formed inside the recess; and a second insulating substrate joined to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, and forming a bonding interface between a second surface side in the thickness direction of the second insulating substrate and the first surface side of the first insulating substrate and the conductive pattern.

[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.

[0009] 2A is a partial cross-sectional view of an electrostatic chuck according to an embodiment of the present invention; FIG. 2B is a schematic plan view of an electrostatic chuck according to an embodiment; FIG. 2C is a partial enlarged view of FIG. 2A of the electrostatic chuck according to an embodiment; FIG. 2D is a plan view showing a portion of an electrostatic chuck according to an embodiment; FIG. 2E is a schematic view of an electrostatic chuck according to an embodiment; FIG. 2F is a time waveform of a voltage output from a chuck driving unit of an electrostatic chuck according to an embodiment; FIG. 2G is a time waveform of a current supplied from a chuck driving unit of an electrostatic chuck according to an embodiment; FIG. 2H is a cross-sectional view showing a step of placing a mask on a first surface side of a first insulator substrate in a method for manufacturing an electrostatic chuck according to an embodiment; FIG. 2H is a cross-sectional view showing a step of performing etching in a method for manufacturing an electrostatic chuck according to an embodiment; FIG. 2I is a cross-sectional view showing a step of forming a conductor pattern in a method for manufacturing an electrostatic chuck according to an embodiment; FIG. 2J is a cross-sectional view showing a step of bonding a second insulator substrate to a first insulator substrate in a method for manufacturing an electrostatic chuck according to an embodiment; 1 is a diagram illustrating the operation of an electrostatic chuck according to a comparative example; FIG. 2 is a diagram illustrating the operation of an electrostatic chuck according to a comparative example; FIG. 3 is a diagram illustrating the operation of an electrostatic chuck according to an embodiment; FIG. 4 is a diagram illustrating a stage and a head equipped with an electrostatic chuck according to a modified example; FIG. 5 is a plan view of a part of a first region of a second insulator substrate according to a modified example; FIG. 6 is a plan view of a part of a second region of a second insulator substrate according to a modified example; FIG. 7 is a diagram illustrating a voltage waveform output from a chuck driving unit according to a modified example when holding an object to be held; FIG. 8 is a diagram illustrating a voltage waveform output from a chuck driving unit according to a modified example when releasing the object to be held; FIG. 9 is a cross-sectional view of a part of an electrostatic chuck according to a modified example; FIG. 10 is a diagram illustrating a state in which an electrostatic chuck according to a modified example holds a substrate; FIG. 11 is a diagram illustrating a state in which an electrostatic chuck according to a modified example has deflected a substrate; and FIG. 12 is a diagram illustrating progress of bonding of substrates held by an electrostatic chuck according to a modified example.FIG. 1 is a diagram showing a state in which substrates held by an electrostatic chuck according to a modified example are bonded together on their entire surfaces; FIG. 2 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 modified example; FIG. 3 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; FIG. 4 is a cross-sectional view of a part of an electrostatic chuck according to a modified example; FIG. 5 is a partial cross-sectional view showing a state after a chamfering process in a manufacturing method for an electrostatic chuck according to a modified example; FIG. 6 is a partial cross-sectional view showing a state after a polishing process in a manufacturing method for an electrostatic chuck according to a modified example.

[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 conductor pattern is to be formed, a conductor pattern forming step of forming a conductor pattern inside the recess, and a bonding step of bonding a second insulating substrate to the first insulating substrate in a state where 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 conductor 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 conductor pattern 21 and the second surface 12b side of the second insulator substrate 12. As shown in FIG. 2A , for example, the first insulator substrate 11 and the second insulator substrate 12 are each formed in a disk shape from a light-transmitting insulating material. 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 a sintered ceramic body. The sintered ceramic body may be Al. ２ O ３ , Y ２ O ３ , AlN, SiN, SiC, Sm ２ O ３ , MgO, MgF ２ , Yb ２ O ３ It is possible to use a material containing the above as a main component.

[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 inside the first region A1, which is circular in plan view. 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 insulator substrates 11 and 12 in the first region A1. The conductor patterns 21A, 21B, and 21C are formed of a metal such as Cu or Al. The conductor patterns 21A, 21B, and 21C are made of a transparent electrode material, specifically, ITO, ZnO, or TiO. ２and graphene. In this case, a camera for capturing an image of the alignment mark provided on the substrate is disposed on the side of the electrostatic chuck 1 opposite to the side that holds the substrate, and the alignment mark of the substrate held by the electrostatic chuck 1 can be captured through the conductor patterns 21A, 21B, and 21C. Here, the distance between the conductor pattern 21 and the surface of the second insulator substrate 12 opposite to the first insulator substrate 11 side 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 electrodes 2111b, 2112b 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 2111a, 2112a arranged along the circumferential direction of the first and second insulator substrates 11, 12. As shown in FIG. 3 , the plurality of electrodes 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 central portions of the first and second insulator substrates 11, 12. The plurality of 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 a bent portion 2111ab, 2112ab that is bent so as to protrude in a direction away from the other terminal electrode 2111a, 2112a in a plan view, and an elongated connecting portion 2111aa, 2112aa that extends along the circumferential direction of the first insulator substrate 11 and the second insulator substrate 12 and connects the ends of two bent portions 2111ab, 2112ab that are adjacent to each other 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. Terminal electrode 2121a has a smaller diameter than terminal electrode 2122a, and is disposed toward the center of first insulator substrate 11 and second insulator substrate 12. Multiple long electrode elements 2121b, 2122b are arranged alternately in first region A1 of first insulator substrate 11 and second insulator substrate 12 along the circumferential direction of first region A1. 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 an elongated 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 way, since the conductor patterns 21A and 21B have the bending portions 2111ab, 2112ab, 2121ab, and 2122ab and the connecting portions 2111aa, 2112aa, 2121aa, and 2122aa, respectively, particularly when the conductor patterns 21A and 21B are formed from metal, 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, it is possible to prevent the alignment mark provided on the substrate from overlapping with any of the bending portions 2111ab, 2112ab, 2121ab, and 2122ab or the connecting portions 2111aa, 2112aa, 2121aa, and 2122aa. Therefore, even if a camera for capturing an image of an alignment mark provided on a substrate is positioned on the opposite side of the electrostatic chuck 1 from the side that holds the substrate, it is possible to capture an image of the alignment mark provided on the substrate held by the electrostatic chuck 1 well.

[0016] 2A , conductor pattern 21C is provided in a second region A2 inside first region A1 of first insulator substrate 11 and second insulator substrate 12. Conductor pattern 21C has a plurality of electrode elements 2131b, 2132b extending radially from the central portions of first insulator substrate 11 and second insulator substrate 12 toward the periphery of first insulator substrate 11 and second insulator substrate 12, and two annular terminal electrodes 2131a, 2132a disposed along the circumferential direction of first insulator substrate 11 and 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 two terminal electrodes 2131a, 2132a 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, for example, a vacuum chamber 100. The current limiting circuit 42 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, and 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, and then a current of approximately 10 mA flows, sufficient to cause the discharge and cause the substrate to fall off. This warning period is approximately 1 second. Therefore, in this embodiment, a 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 (shutting 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 a 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 reduces the likelihood of the substrate falling off. The voltages V1 and V2 are set to values ​​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 reduces discharges 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 a recess 11a is 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 a 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 surface 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 into 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 conductor patterns 21 are formed inside all of the recesses 11a of the first insulator 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 11 b of the first insulator substrate 11, so that the second surface 12 b of the second insulator substrate 12 is brought into surface contact with the first surface 11 b 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 11 b of the first insulator substrate 11 and the second surface 12 b 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 11 b and 12 b 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 conductor pattern forming process, if the thickness of the layer 9021 of material that forms the base of the conductor pattern 21 inside the recess 11a is thinner than the depth of the recess 11a, as shown in Fig. 6A, a gap S9001 will be formed between the second insulator substrate 12 and the recess 11a, as shown in Fig. 6B, resulting in a decrease in strength. In this case, if particles are present between the second insulator substrate 12 and the object to be held, a force will be applied through the particles in a direction that pushes the second insulator substrate 12 into the gap S9001 when the object to be held is joined, which may cause the second insulator substrate 12 to crack. For this reason, it is preferable to deposit a larger amount of material that forms the base of the conductor pattern 21, as shown in Fig. 6C, and then polish it to form the conductor pattern 21 as shown in Fig. 6D.

[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 the first insulator substrate 11, and then the conductor pattern is sandwiched between the first insulator substrate 11 and the second insulator 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 insulator substrate 11 and the second insulator 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 insulator 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 in the thickness direction of the first insulator substrate 11. This eliminates the need to melt the first insulator substrate 11 and the second insulator substrate 12 before welding them to each other. 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 electrostatic chuck according to the comparative example shown in FIG. 7A , for example, the distance H11 between the conductor 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 conductor pattern 11021, is 0.1 μm to 1.0 μm. In this case, attraction of the substrate W1 by Coulomb force is dominant. In the electrostatic chuck according to the comparative example shown in FIG. 7B , for example, the distance H12 between the conductor 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 conductor pattern 12021, is 2 μm to 5 μm. In this case, attraction of the substrate W1 by the Johnsen-Rahbek force is dominant. 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, charge generated within the substrate tends to accumulate within the substrate when the substrate is released. Even after the substrate is released, the charge accumulated within the substrate can cause the substrate to remain attached to the electrostatic chuck for a long time. In contrast, the electrostatic chuck 1 according to this embodiment holds the object by directly utilizing Coulomb force without using a virtual electrode, 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, charge generated within the object quickly dissipates, preventing the object from adhering to the electrostatic chuck. Furthermore, when the electrostatic chuck 1 according to this embodiment holds the object, multiple regions charged with different polarities are alternately generated 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 (indicated by the 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 each of the multiple regions within the held object are easily eliminated by being offset between adjacent regions of opposite polarity, and when an operation to release the held object is performed, the charges generated in the held object are quickly eliminated, preventing the held 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 held object and the electrode elements 2111b, 2112b, 2121b, and 2122b are advantageous in that they are easily eliminated. In particular, the electrostatic chuck 1 according to the present embodiment is preferable because it is easy to eliminate charges even between adjacent electrode elements 2111b, 2112b, 2121b, and 2122b.

[0027] Furthermore, when the atmosphere around the electrostatic chuck 1 is changed from atmospheric air to a high vacuum state or from a high vacuum state to atmospheric air, 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 V to several thousand V is applied, discharge is likely to occur at the portions of the terminal electrodes 2111 a, 2112 a, the terminal electrodes 2121 a, 2122 a, and the terminal electrodes 2131 a, 2132 a that are exposed to the outside of the electrostatic chuck 1. Once discharge occurs, the voltage applied to the conductor pattern 21 drops, which reduces the chucking force of the electrostatic chuck 1, and there is a risk that the held object will unintentionally fall. In contrast, the chuck driving unit 4 according to the present embodiment includes a voltage application unit 41 that applies a voltage between the terminal electrodes 2121 a and 2122 a via the power supply lines L21 and L22, and a current limiting circuit 42 that limits the current flowing between the terminal electrodes 2111 a and 2112 a, between the terminal electrodes 2121 a and 2122 a, and between the terminal electrodes 2131 a and 2132 a 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 2111 a and 2112 a, between the terminal electrodes 2121 a and 2122 a, and between the terminal electrodes 2131 a and 2132 a. 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, the recess 11a may be formed by blasting the region on the first surface 11b of the first insulator substrate 11 where the conductor pattern 21 is to be formed. Alternatively, the region on the first surface 11b of the first insulator substrate 11 where the conductor pattern 21 is to be formed may be blasted to form the recess 11a of a predetermined depth in the region on the first insulator substrate 11 where the conductor pattern 21 is to be formed, and then the inside of the recess 11a of the 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 on the first insulator substrate 11 by etching alone, 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 recess 11a is formed by using a dry etching technique in the region where the conductor pattern 21 is to be formed on the first surface 11b side of the first insulator substrate 11 in the recess formation step. However, this is not a limitation, and the recess 11a may also be formed by using, for example, a wet etching technique. Also, in the embodiment, an example has been described in which an Ar particle beam is used, but this is not a limitation, and in the recess formation step, for example, a SF ６ Alternatively, the recess 11a may be formed by reactive ion etching using such a reactive gas.

[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 conductor 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 on at least one of the layers to be etched by exposing it to 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 by irradiating a particle beam 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 by irradiating a particle beam may be performed only on 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 11 b of the first insulator substrate 11 and the second surface 12 b of the second insulator substrate 12, and then a radical treatment is performed by irradiating the first surface 11 b and the second surface 12 b 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 the embodiment, for example, as in an electrostatic chuck 2001 shown in Fig. 8, the second insulator substrate 12 may be formed from transparent glass and have a ceramic material region 2015 arranged on the second insulator substrate 12 except for the peripheral portion. 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 is a ceramic containing a metal element, for example, AlN, Al ２ O ３ Alternatively, yttria may be used. Conductor patterns 2021B and 2021A are embedded in the ceramic material region 2016 and in 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 with respect to the conductive pattern 2021B. Here, since ceramics have a higher thermal conductivity than glass, it is preferable that the heater 2016 be embedded 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 range finder 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 at the center, and the second insulator substrate 12 and the first insulator substrate 11 are joined together in the same manner as 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 step is performed in which the ceramic material region 2015 is formed by repeating the steps of forming a conductor pattern serving as a base of the heater 2016 in the opening at 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, because 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, if charged, the charge is difficult to dissipate. In contrast, according to the present configuration, the ceramic material forming the ceramic material region 2015 can have an adjustable insulation resistance 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, along with the conductor pattern 21 for performing the function of the electrostatic chuck 1, can be embedded in the second insulator substrate 12.

[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 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. Also, in the second region A2, as shown in FIG. 9B , a groove 4032d is formed 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 along the extension direction of 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, for example, a gas containing helium. Furthermore, when the surface roughness of the third surface is several tens of μm or less in Ra 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, for example, 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 still held thereon, so that the object can be easily removed from the electrostatic chuck 1 .

[0045] Furthermore, the method for manufacturing 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 a thickness direction of a first insulator substrate, a resin application step of applying a transparent ultraviolet-curable resin material to the first surface side of the first insulator substrate, and, after the resin application forming step, a bonding step of bonding a second insulator substrate to the first insulator substrate in a state in which a second surface side of the second insulator substrate to be bonded to the first insulator substrate in the thickness direction is in surface contact with the first surface side of the first insulator substrate. In this case, as shown in FIG. 11 , for example, 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 11 b 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 11 b 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 the conductor pattern 3021 and the surface of the second insulator substrate 12 opposite to the conductor pattern 3021 side may be 1.0 mm or less. Furthermore, when the 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 12 c of the second insulator substrate 12 may have grooves formed in each of a first region A1 facing the periphery of the disk-shaped substrate, which is the object to be held, and a second region A2 inside the first region A1, and may be provided with a gas discharge portion that discharges gas into the groove when the object to be held is held on the third surface 12 c side of the second insulator substrate 12. These configurations also achieve the same effects as the electrostatic chuck 1 having the metal conductor pattern 21 described in the embodiment.

[0049] Incidentally, ITO deteriorates when heated to temperatures of 100° C. or higher or 150° C. or higher. 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 150° C. Therefore, deterioration of the ITO can be suppressed.

[0050] The embodiment or each of the above-described modified examples may include a pressing mechanism that presses the center of a substrate, which is a held object held on the insulating substrate, 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 on a stage 5401 and a 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 the head 5402 compared to the periphery of the substrate W2, and then the center of the substrate W2 is brought into contact with the center of the 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 the substrates W2 and W1 proceeds from the center toward the periphery, as shown by arrow AR52 in FIG. 12C . Then, as shown in FIG. 12D, the substrates W1 and W2 are bonded together 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 the present configuration, the substrates W1 and W2 naturally separate from the electrostatic chuck, so that the substrates W1 and W2 can be bonded to each other with high precision and 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 the substrate to be held. Here, the protective layer may be formed from diamond-like carbon (hereinafter referred to as "DLC") or a resin. Examples of resins that can be used include polyimide and polytetrafluoroethylene. 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 insulator substrate 11 and the second insulator 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 in which a protective layer is formed on at least the third surface of the second insulator substrate 12. Here, if the protective layer is made of DLC, the DLC is deposited on the third surface of the second insulator 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] In an example of an electrostatic chuck including a protective layer approximately 500 nm thick 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 including a second insulator substrate 12 made from synthetic quartz, providing a protective layer made from DLC so as to cover the portion that contacts the substrate held by the electrostatic chuck can increase the hardness of the portion that contacts the substrate and suppress 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 the electrostatic chuck including 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 that transmits through a Si substrate, i.e., the wavelength band of 1100 nm to 1200 nm. This shows that when an electrostatic chuck having a protective layer formed from DLC is used, an alignment mark provided on a substrate held by the electrostatic chuck can be imaged 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 approximately 1.5 μm showed a transmittance of approximately 90% in the wavelength band of light that transmits 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 that transmits 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 portion with the substrate, thereby suppressing damage to the substrate due to damage to the contact portion. Furthermore, when the protective layer is made of an elastically deformable resin such as polyimide, 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 insulator 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 insulator substrate 12, the inclined surface being inclined so that the further it is positioned from the third surface toward the first insulator substrate 11, the further away it is from the central axis extending in the thickness direction of the second insulator 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 6011 b of the first insulator substrate 6011, a transparent resin layer 6013 covering portions of the first surface 6011 b of the first insulator substrate 6011 other than the conductor pattern, and a second insulator substrate 6012 bonded to cover the resin layer 6013 and the conductor pattern. A through-hole 6001 a is formed in the center of the electrostatic chuck 6001, and a pressing member (not shown) is inserted through the through-hole 6001 a to press the center of a substrate held by the electrostatic chuck 6001. 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 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 on the first surface 6011b side of the through hole 6001a 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 modified example 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. Thereafter, 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 in 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 further it is from the third surface 6012c toward the first insulator substrate 6011, the more distant it is from the central axis J6. The first insulator substrate 6011 has the aforementioned 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 also formed over the entire periphery of the through-hole 6001a on the first surface 6011b side of the first insulator substrate 6011. Subsequently, 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.

[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.

[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: Connection portion, 2111ab, 2112ab, 2121ab, 2122ab: Bent portion, 2111b, 2112b, 2121b, 2122b, 2131b, 2132b: Electrode element, 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 method for manufacturing an electrostatic chuck, comprising: a recess forming step of forming a recess in an area on a first surface side in the thickness direction of a 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 insulating substrate to the first insulating substrate in a state where a second surface side to be joined to the first insulating substrate in the thickness direction of the second insulating substrate is in surface contact with the first surface side of the first insulating substrate after the conductor pattern forming step.

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

3. The method for manufacturing an electrostatic chuck according to claim 2, wherein 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.

4. A method for manufacturing an electrostatic chuck according to any one of claims 1 to 3, further comprising an activation treatment step of activating at least one of the first surface side of the first insulating substrate and the second surface side of the second insulating substrate prior to the bonding step.

5. The method for manufacturing an electrostatic chuck according to claim 4, wherein in the joining step, the second insulator substrate is joined to the first insulator substrate while maintaining the temperature of the second insulator substrate at 200° C. or less.

6. The method for manufacturing an electrostatic chuck according to claim 4, wherein in the bonding step, the second insulating substrate is bonded to the first insulating substrate in a hydrophilic manner.

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

8. The method for manufacturing an electrostatic chuck according to claim 6, wherein in the activation treatment step, a particle beam is irradiated to at least one of the first surface side of the first insulating substrate and the second surface side of the second insulating substrate.

9. The method for manufacturing an electrostatic chuck according to any one of claims 1 to 3, wherein the bonding step is carried out under reduced pressure.

10. The conductor pattern is made of ITO, ZnO, TiO ２ The method for manufacturing an electrostatic chuck according to claim 1 , wherein the electrostatic chuck is made of at least one material selected from the group consisting of graphene and graphene.

11. The method for manufacturing an electrostatic chuck according to any one of claims 1 to 3, further comprising 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.

12. A method for manufacturing an electrostatic chuck as described in any one of claims 1 to 3, further comprising a protective layer forming step of forming a protective layer on at least a third surface of the second insulating substrate opposite the second surface in the thickness direction of the second insulating substrate.

13. The method for manufacturing an electrostatic chuck according to claim 12, wherein the protective layer is made of diamond-like carbon or resin.

14. A method for manufacturing an electrostatic chuck as claimed in any one of claims 1 to 3, further comprising: a chamfering process, after the joining process, for chamfering at least the entire peripheral portion of a third surface side of the second insulator substrate opposite the second surface side in the thickness direction of the second insulator substrate, thereby forming an inclined surface that is inclined so as to move away from the central axis extending in the thickness direction of the second insulator substrate the further it is positioned from the third surface toward the second insulator substrate, over the entire peripheral portion of the third surface side of the second insulator substrate; a first polishing process, after the chamfering process, for polishing the inclined surface; and a second polishing process, after the first polishing process, for polishing the third surface side of the second insulator substrate.

15. The method for manufacturing an electrostatic chuck according to claim 11, wherein 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.

16. An electrostatic chuck comprising: a first insulating substrate having a recess formed on a first surface side in a thickness direction; a conductor pattern formed inside the recess; and a second insulating substrate joined to the first insulating substrate so as to cover the entire first surface side of the first insulating substrate, forming a bonding interface between a second surface side in the thickness direction and the first surface side of the first insulating substrate and the conductor pattern.

17. An electrostatic chuck comprising: a first insulating substrate having a recess formed on a first surface side in the thickness direction; a conductor pattern formed inside the recess; and a second insulating substrate joined to the first insulating substrate in a solid state so as to cover the entire first surface side of the first insulating substrate.

18. An electrostatic chuck according to claim 16 or 17, wherein the 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.

19. An electrostatic chuck as described in claim 16 or 17, wherein the conductor pattern 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 inside the recess so as to be alternately arranged along a predetermined first direction.

20. The electrostatic chuck according to claim 19, wherein the distance between two adjacent first electrodes or between two adjacent second electrodes is 2.0 mm or less.

21. The electrostatic chuck according to claim 16 or 17, wherein the conductor pattern includes a first terminal electrode and a second terminal electrode, and further comprises: a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode; and a current limiting circuit that limits the current flowing between the first terminal electrode and the second terminal electrode when the current reaches a preset current threshold, and the current threshold is smaller than a current value of a discharge start current at which the held object does not fall off.

22. The conductor pattern is made of ITO, ZnO, TiO ２ 18. The electrostatic chuck of claim 16 or 17, formed from at least one material selected from the group consisting of graphene and graphene.

23. The electrostatic chuck according to claim 16 or 17, wherein the conductor pattern is a transparent electrode.

24. An electrostatic chuck as described in claim 16 or 17, wherein the second insulating substrate is transparent and has a ceramic material region formed from a ceramic material and arranged so as to be exposed at least on the side of the second insulating substrate opposite to the first insulating substrate side, and the ceramic material contains a metal element.

25. The ceramic material is AlN, Al ２ O ３ or yttria.

26. The electrostatic chuck according to claim 16 or 17, further comprising a protective layer covering a third surface of the second insulating substrate opposite to the second surface bonded to the first insulating substrate at least in the thickness direction of the second insulating substrate.

27. The electrostatic chuck according to claim 26, wherein the protective layer is formed from diamond-like carbon or resin.

28. An electrostatic chuck as described in claim 16 or 17, wherein an inclined surface is formed on at least the second insulating substrate around the entire periphery of a third surface side opposite to the 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 the central axis extending in the thickness direction of the second insulating substrate as it moves from the third surface toward the second insulating substrate.

29. The electrostatic chuck described in claim 16, wherein a third surface of the second insulating substrate opposite to the first insulating substrate is roughened, and the electrostatic chuck further comprises a gas ejection section which ejects 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.

30. The electrostatic chuck described in claim 16, wherein a groove is formed in at least the second region of a first region on a third surface of the second insulating substrate opposite to the first insulating substrate side, the first region facing a periphery of an object to be held in a state where the object to be held is held on the third surface side of the second insulating substrate, and a second region inside the first region, and further comprising a gas discharge portion which discharges gas into the groove in a state where the object to be held is held on the third surface side of the second insulating substrate.

31. The electrostatic chuck of claim 29 or 30, wherein the gas comprises at least one of argon, nitrogen, and helium.

32. An electrostatic chuck comprising: 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; and 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, wherein the current threshold is smaller than a current value of a discharge start current at which a held object does not fall off.

33. An electrostatic chuck comprising: an insulating substrate; a conductor pattern embedded in the insulating substrate and including a first terminal electrode and a second terminal electrode; and a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode, wherein 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 when releasing the hold of an object to be held.

34. The electrostatic chuck of claim 33, further comprising a pressing mechanism for pressing a portion of a held object held on the insulating substrate at a central portion of the insulating substrate, wherein after releasing the held object in a second region inside a first region facing a periphery of the held object, the pressing mechanism presses the central portion of the held object to bend the central portion of the held object so that the central portion of the held object protrudes in a direction away from the insulating substrate compared to the periphery of the held object, and in this state, the central portion of the held object is brought into contact with a central portion of a joining object to be joined to the held object, thereby proceeding with joining of the held object and the joining object.

35. An electrostatic chuck comprising: an insulating substrate; a conductor pattern embedded in the insulating substrate and including a first terminal electrode and a second terminal electrode; and a voltage application unit that applies a voltage between the first terminal electrode and the second terminal electrode, wherein when holding an object to be held, the voltage application unit applies an alternating voltage having a frequency of 2 Hz or more and whose amplitude gradually increases over time between the first terminal electrode and the second terminal electrode, and then holds the object to be held.

36. A method for manufacturing an electrostatic chuck, comprising: a conductor pattern forming step of forming a conductor pattern made of ITO on a first surface side in the thickness direction of a first insulating substrate; a resin application step of applying an ultraviolet-curing resin material to the first surface side of the first insulating substrate; and a bonding step of bonding the second insulating substrate to the first insulating substrate in a state in which a second surface side to be bonded to the first insulating substrate in the thickness direction of the second insulating substrate is brought into surface contact with the first surface side of the first insulating substrate.

37. An electrostatic chuck comprising: a first insulating substrate; a conductor pattern made of a transparent conductive material formed on a first surface side of the first insulating substrate in the thickness direction; a resin layer made of an ultraviolet-curing resin material and interposed in an area on the first surface side of the first insulating substrate excluding the conductor pattern; and a second insulating substrate arranged to cover the conductor pattern and the resin layer.

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