Electrostatic chuck device

Abstract

To provide an electrostatic chuck device with excellent reliability.SOLUTION: An electrostatic chuck device comprises: an electrostatic chuck plate which has a dielectric substrate having a mounting surface for mounting a wafer and a suction electrode located inside the dielectric substrate; and a metal base which supports, on its supporting surface, a rear surface of the dielectric substrate located on the opposite side to the mounting surface. The dielectric substrate and the metal base are bonded to each other via intermolecular force. Between the dielectric substrate and the metal base, there is provided a positioning mechanism for suppressing positional deviation of the dielectric substrate from the supporting surface in a surface direction of the supporting surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrostatic chuck device.

Background Art

[0002] In the semiconductor manufacturing process, an electrostatic chuck device for holding a semiconductor wafer in a vacuum environment is used. The electrostatic chuck device places a plate-like sample such as a semiconductor wafer on a mounting surface, generates an electrostatic force between the plate-like sample and an internal electrode, and adsorbs and fixes the plate-like sample. As such an electrostatic chuck device, Patent Document 1 discloses a configuration in which an electrostatic chuck member capable of adsorbing a wafer is installed on a metal cooling base member via an adhesive layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the high integration and high performance of semiconductor elements, the miniaturization of wafer processing has been progressing. In order to perform fine processing of semiconductors, it is required to perform plasma etching in a state where the semiconductor is controlled at a lower temperature. Generally, it is known that the elastic modulus of an adhesive layer that joins a metal base and an electrostatic chuck plate increases in a low-temperature environment. Therefore, the adhesive layer in a low-temperature environment may not sufficiently relieve the thermal stress between the metal base and the electrostatic chuck plate, and there is a risk of damage to the electrostatic chuck plate. That is, in the electrostatic chuck device with the conventional structure, use in a low-temperature environment has not been sufficiently assumed, and there has been a problem with reliability.

[0005] An object of the present invention is to provide an electrostatic chuck device with excellent reliability.

Means for Solving the Problems

[0006] One aspect of the electrostatic chuck device of the present invention includes a dielectric substrate having a mounting surface on which a wafer is mounted, and an electrostatic chuck plate having a suction electrode located inside the dielectric substrate, and a metal base that supports the back surface of the dielectric substrate located on the opposite side of the mounting surface on a support surface. The dielectric substrate and the metal base are joined to each other by intermolecular forces, and a positioning mechanism is provided between the dielectric substrate and the metal base to suppress displacement of the dielectric substrate with respect to the support surface in the plane direction of the support surface.

[0007] In the above-described electrostatic chuck device, the true contact area between the back surface and the support surface may be configured to be 0.005% or more and 40% or less.

[0008] In the above-described electrostatic chuck device, the electrostatic chuck plate may be configured to adsorb the metal base to the back surface by applying a voltage to the suction electrode.

[0009] In the above-described electrostatic chuck device, the positioning mechanism includes a plurality of convex portions protruding from one of the back surface and the support surface to the other, and a plurality of concave portions provided on the other, into which the convex portions are respectively inserted. The plurality of concave portions may be configured to extend along the radial direction with respect to the center of the support surface.

[0010] In the above-described electrostatic chuck device, a cooling device that contacts the surface of the metal base opposite to the support surface is further provided, and the cooling device may have a heat pipe structure.

[0011] In the above-described electrostatic chuck device, a jig insertion concave portion that opens radially outward may be provided at least at the outer edge of one of the back surface and the support surface.

Advantages of the Invention

[0012] According to one aspect of the present invention, an electrostatic chuck device with excellent reliability is provided.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0014] Hereinafter, each embodiment of the electrostatic chuck device of the present invention will be described with reference to the drawings. In all the following drawings, for the sake of easy viewing of the drawings, the dimensions, ratios, etc. of each component may be appropriately shown differently.

[0015] FIG. 1 is a schematic diagram of the electrostatic chuck device 1 of the present embodiment. The electrostatic chuck device 1 includes an electrostatic chuck plate 2 that adsorbs and supports a wafer W, a metal base 3 that supports the electrostatic chuck plate 2, a power supply terminal 16 that applies a voltage to the electrostatic chuck plate 2, and a cooling device 5 that cools the metal base 3. In FIG. 2, the cooling device 5 is omitted. A focus ring surrounding the wafer W may be disposed on the outer peripheral portion of the upper surface of the electrostatic chuck plate 2.

[0016] FIG. 2 is a cross-sectional view showing a part of the electrostatic chuck device 1 of the present embodiment. The electrostatic chuck plate 2 has a dielectric substrate 11 and a suction electrode 13 located inside the dielectric substrate 11. The electrostatic chuck plate 2 adsorbs the wafer W on the mounting surface 11s provided on the dielectric substrate 11.

[0017] In the following description, each part of the electrostatic chuck device 1 will be described with the side on which the wafer W is mounted with respect to the electrostatic chuck plate 2 being the upper side and the side of the metal base 3 being the lower side. However, the up and down directions here are merely directions used for the sake of simplicity of explanation and do not limit the posture of the electrostatic chuck device 1 during use.

[0018] The dielectric substrate 11 is made of a composite sintered body having sufficient mechanical strength and durability against corrosive gases and their plasmas. As the dielectric material constituting the dielectric substrate 11, ceramics having mechanical strength and durability against corrosive gases and their plasmas are preferably used. Examples of the ceramics constituting the dielectric substrate 11 include aluminum oxide (Al 2 O 3 ) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al 2 O 3 )-silicon carbide (SiC) composite sintered body, etc. are preferably used. In particular, from the viewpoints of dielectric properties at high temperatures, high corrosion resistance, plasma resistance, and heat resistance, the material constituting the dielectric substrate 11 is preferably an aluminum oxide (Al 2 O 3 )-silicon carbide (SiC) composite sintered body.

[0019] The dielectric substrate 11 is circular and plate-shaped in plan view. The dielectric substrate 11 has a mounting surface 11s on which the wafer W is placed and a back surface 11p facing the opposite side of the mounting surface 11s. For example, a plurality of protrusions (not shown) are formed on the mounting surface 11s at predetermined intervals. The mounting surface 11s supports the wafer W at the tip portions of the plurality of protrusions.

[0020] The adsorption electrode 13 is disposed inside the dielectric substrate 11. The adsorption electrode 13 extends in a plate shape along the mounting surface 11s of the dielectric substrate 11. When a voltage is applied to the adsorption electrode 13, an electrostatic adsorption force for holding the wafer W on the mounting surface 11s of the dielectric substrate 11 is generated.

[0021] The suction electrode 13 is composed of a composite of an insulating material and a conductive material. The insulating material contained in the suction electrode 13 is not particularly limited. For example, it is preferably at least one selected from the group consisting of aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), silicon nitride (Si 3 N 4 ), yttrium(III) oxide (Y 2 O 3 ), yttrium aluminum garnet (YAG), and SmAlO 3 . The conductive material contained in the suction electrode 13 is preferably at least one selected from the group consisting of molybdenum carbide (Mo 2 C), molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0022] The power supply terminal 16 is in contact with the suction electrode 13. The power supply terminal 16 extends downward from the suction electrode 13. The power supply terminal 16 passes through the hole 15 of the dielectric substrate 11. Further, the power supply terminal passes through the inside of a cylindrical insulator 23 housed in the holding hole 17 of the metal base 3. The power supply terminal 16 is connected to an external power supply 24. The power supply 24 applies a voltage to the suction electrode 13. The number, shape, etc. of the power supply terminals 16 are determined by the form of the suction electrode 13, that is, whether it is a unipolar type or a bipolar type. In the present embodiment, the power supply terminal 16 is arranged at the center of the electrostatic chuck plate 2.

[0023] The metal base 3 is a disc-shaped metal member in plan view. The material constituting the metal base 3 is not particularly limited as long as it is a metal excellent in thermal conductivity, electrical conductivity, and workability, or a composite material containing these metals. As the material constituting the metal base 3, for example, alloys such as aluminum (Al), copper (Cu), stainless steel (SUS), and titanium (Ti) are preferably used. From the viewpoints of thermal conductivity, electrical conductivity, and workability, an aluminum alloy is preferable as the material constituting the metal base 3. At least the surface of the metal base 3 exposed to plasma is preferably subjected to anodizing treatment or resin coating with a polyimide-based resin. More preferably, the entire surface of the metal base 3 is subjected to the above anodizing treatment or resin coating. By subjecting the metal base 3 to anodizing treatment or resin coating, the plasma resistance of the metal base 3 is improved and abnormal discharge is prevented. Therefore, the plasma resistance stability of the metal base 3 is improved, and the occurrence of surface scratches on the metal base 3 can also be prevented.

[0024] The body of the metal base 3 also functions as an internal electrode for plasma generation. The body of the metal base 3 is connected to an external high-frequency power supply 22 via a matcher (not shown).

[0025] The metal base 3 supports the electrostatic chuck plate 2 from below. The metal base 3 has a support surface 3a facing upward and a lower surface 3b facing the opposite side of the support surface 3a. The support surface 3a faces the back surface 11p of the dielectric substrate 11 in the vertical direction. The support surface 3a is in contact with the back surface 11p. That is, the metal base 3 supports the back surface 11p of the dielectric substrate 11 at the support surface 3a.

[0026] As shown in FIG. 1, the metal base 3 is mounted on the cooling device 5. The cooling device 5 of the present embodiment has a heat pipe structure.

[0027] The cooling device 5 has a heat absorption chamber 5c, a heat dissipation chamber 5d, and a connecting pipe 5e that are filled with a refrigerant inside. The refrigerant L receives heat from the object to be cooled and vaporizes in the heat absorption chamber 5c, and then moves to the heat dissipation chamber 5d. Also, the refrigerant L is cooled by the heat exchanger 6 in the heat dissipation chamber 5d and condenses back into a liquid. Due to these actions, the cooling device 5 transfers heat from the object to be cooled to the heat exchanger 6.

[0028] The cooling device 5 has a cooling surface 5a for cooling the object to be cooled. The cooling surface 5a is provided on the outer surface of the heat absorption chamber 5c. Therefore, the cooling device 5 receives heat from the object to be cooled at the cooling surface 5a and transfers the heat to the refrigerant L inside the heat absorption chamber 5c.

[0029] The metal base 3 contacts the cooling surface 5a at the lower surface (the surface to be cooled) 3b, which is the surface opposite to the support surface 3a. The entire lower surface 3b of the metal base 3 is in surface contact with the cooling surface 5a of the cooling device 5. Therefore, the cooling device 5 can cool the metal base 3 uniformly throughout the plane of the lower surface 3b. The cross-sectional shape of the metal base 3 in a plane orthogonal to the vertical direction is substantially uniform at any position in the vertical direction. For this reason, the heat of the electrostatic chuck plate 2 is uniformly transmitted in the cross-section of the metal base 3, reaches the lower surface 3b from the support surface 3a, and moves from the lower surface 3b to the cooling surface 5a. According to the present embodiment, through the metal base 3 and the electrostatic chuck plate 2, the wafer W mounted on the mounting surface 11s of the electrostatic chuck plate 2 can be cooled uniformly in the plane.

[0030] Note that, compared with the present embodiment, the metal base 3 of the conventional structure had a refrigerant flow path provided inside, and the metal base was cooled using the refrigerant. When adopting such a structure, since the refrigerant cools the metal base along the flow path, it was difficult to avoid temperature unevenness on the support surface. According to the cooling device 5 of the present embodiment, the temperature unevenness of the wafer W, which is a problem of the conventional structure, can be more effectively eliminated.

[0031] Since the cooling device 5 of the present embodiment has a heat pipe structure, depending on the selection of the refrigerant L, the metal base 3 can be cooled to an extremely low temperature. As an example, when liquid nitrogen is used as the refrigerant L, the metal base 3 can be cooled to -100°C or lower.

[0032] As shown in FIG. 2, in the present embodiment, the support surface 3a of the metal base 3 and the back surface 11p of the dielectric substrate 11 are in direct contact without interposing other members. That is, no adhesive layer as conventionally known is provided between the metal base 3 and the dielectric substrate 11.

[0033] In the present embodiment, the dielectric substrate 11 and the metal base 3 are joined to each other by intermolecular forces. When a stress greater than the intermolecular force is applied between the dielectric substrate 11 and the metal base 3, a change in the relative position between the dielectric substrate 11 and the metal base 3 is allowed. The dielectric substrate 11 and the metal base 3 move relative to each other in the plane direction at the joint surface when a stress is applied in the shear direction of the joint surface.

[0034] In this specification, "the dielectric substrate 11 and the metal base 3 are joined" means that even when the weight of the electrostatic chuck plate 2 is applied to the joint surface with the support surface 3a of the metal base 3 facing downward under vacuum, the dielectric substrate 11 does not separate from the metal base 3. For example, when a dielectric substrate 11 made of ceramic with a thickness of around 5 mm is used, the pressure due to the weight of the dielectric substrate 11 is about 190 Pa. On the other hand, when the true contact area is 0.005% or more, the intermolecular force acting between the dielectric substrate 11 and the metal base 3 is about 410 Pa. Therefore, when the true contact area is 0.005% or more, the intermolecular force sufficiently exceeds the weight of the dielectric substrate 11, and the separation of the dielectric substrate 11 from the metal base 3 due to its own weight can be suppressed.

[0035] In plasma etching using the electrostatic chuck device 1, when the wafer W is irradiated with plasma, the surface temperature of the wafer W rises. On the other hand, the metal base 3 is cooled by the cooling device 5. That is, the electrostatic chuck device is heated from above and cooled from below. Further, while the metal base 3 is made of a metal material, the dielectric substrate 11 is made of ceramics or the like, so the thermal expansion coefficient of the dielectric substrate 11 and the thermal expansion coefficient of the metal base 3 are significantly different. For this reason, when performing plasma etching, a relative displacement due to the difference in thermal expansion coefficient occurs between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3.

[0036] According to the present embodiment, the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3 are joined by intermolecular forces, so that relative displacement in the plane direction between the back surface 11p and the support surface 3a is allowed. Thereby, even when the metal base 3 is cooled to an extremely low temperature, it is possible to suppress the occurrence of excessive stress in the dielectric substrate 11 due to the difference in thermal expansion coefficient. As a result, damage to the dielectric substrate 11 can be suppressed, and the reliability of the electrostatic chuck device 1 can be improved.

[0037] According to the present embodiment, no adhesive is used for joining the dielectric substrate 11 and the metal base 3. Generally, since the elastic modulus of the adhesive increases in a low-temperature environment, when an adhesive is used for joining the dielectric substrate and the metal base, the adhesive cannot sufficiently follow the relative displacement caused by the difference in thermal expansion coefficient between the dielectric substrate and the metal base, and peeling is likely to occur in the adhesive. According to the present embodiment, since the dielectric substrate and the metal base are joined by intermolecular forces, stable joining strength can be obtained with respect to temperature changes.

[0038] According to the present embodiment, the dielectric substrate 11 and the metal base 3 are in direct contact. For this reason, compared with the case where an adhesive layer is provided between the dielectric substrate 11 and the metal base 3, the heat transfer efficiency between the dielectric substrate 11 and the metal base 3 can be increased. According to the present embodiment, it is possible to provide the electrostatic chuck device 1 having high cooling responsiveness and excellent cooling efficiency.

[0039] Generally, it is known that the strength of the intermolecular force acting between two members is correlated with the true contact area between the two members. In the present embodiment, by increasing the true contact area between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3, the intermolecular force between the dielectric substrate 11 and the metal base 3 can be made to act strongly.

[0040] The true contact area between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3 is preferably 0.005% or more and 40% or less, and more preferably 0.06% or more and 40% or less.

[0041] The lower limit value of 0.005% of the true contact area is calculated based on preferable heat transfer between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3. By setting the true contact area between the back surface 11p and the support surface 3a to 0.005% or more, the heat transfer efficiency between the dielectric substrate 11 and the metal base 3 can be sufficiently increased, and the electrostatic chuck device 1 with high thermal responsiveness can be provided. In addition, by setting the true contact area between the back surface 11p and the support surface 3a to 0.005% or more, the bonding force due to the intermolecular force between the dielectric substrate 11 and the metal base 3 can be increased, and the detachment of the dielectric substrate 11 from the metal base 3 can be suppressed. Note that when the true contact area between the back surface 11p and the support surface 3a is 0.006% or more, an excellent electrostatic chuck device can be provided in which the heat transfer efficiency is further increased and the bonding force due to the intermolecular force between the dielectric substrate 11 and the metal base 3 is further increased.

[0042] The upper limit value of 40% of the true contact area is calculated based on the upper limit value of the intermolecular force acting between the dielectric substrate 11 and the metal base 3. If the intermolecular force is too large, there is a risk that the metal base 3 will undergo plastic deformation due to the intermolecular force.

[0043] The metal base 3 undergoes plastic deformation with respect to a stress of generally 3 MPa or more. Also, generally, the van der Waals stress P v(z) is known to be expressed by the following equation using the hammer constant A and the contact distance z. Here, it is assumed that the van der Waals stress coincides with the intermolecular stress (intermolecular force per unit area).

[0044]

Equation

[0045] In the above equation, when the contact distance z is assumed to be 1 nm and the true contact area that can sufficiently suppress the plastic deformation of the metal base is calculated, it is found that it is preferable to set the true contact area to 40% or less.

[0046] Furthermore, when the true contact area between the back surface 11p and the support surface 3a is too large, the intermolecular force acting between the back surface 11p and the support surface 3a becomes too large, making it difficult for the dielectric substrate 11 and the metal base 3 to move relative to each other along the plane direction of the bonding surface. In this case, the intermolecular force between the dielectric substrate 11 and the metal base 3 inhibits the free expansion of the dielectric substrate 11 and the metal base 3, and there is a risk of damage to the dielectric substrate 11 due to thermal stress. By setting the true contact area between the back surface 11p and the support surface 3a to 40% or less, the bonding force caused by the intermolecular force between the dielectric substrate 11 and the metal base 3 can be suppressed to such an extent that movement in the plane direction of the bonding surface can occur before damage is caused to the dielectric substrate 11 by the thermal stress caused by the difference in the thermal expansion coefficients of the dielectric substrate 11 and the metal base 3.

[0047] Note that the range of the true contact area described above is more precisely defined by the thermal expansion coefficients of the dielectric substrate 11 and the metal base 3. Even when the material of the dielectric substrate 11 is an aluminum oxide (Al 2 O 3 )-silicon carbide (SiC) composite sintered body and the material of the metal base 3 is an aluminum alloy, it is preferable that the true contact area between the back surface 11p and the support surface 3a is 0.005% or more and 40% or less.

[0048] The back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3 are polished by polishing means such as lapping. By polishing the back surface 11p and the support surface 3a using appropriate abrasive grains, a state of contact with a true contact area within the above-described range can be realized.

[0049] In the electrostatic chuck device 1 of the present embodiment, by applying a voltage to the adsorption electrode 13, an electrostatic force is generated not only between the adsorption electrode 13 and the wafer W but also between the adsorption electrode 13 and the metal base 3. Thereby, the wafer W is adsorbed on the placement surface 11s of the dielectric substrate 11, and the support surface 3a of the metal base 3 is adsorbed on the back surface 11p of the dielectric substrate 11. This electrostatic force assists the bonding by the intermolecular force between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3, and makes the bonding between the back surface 11p and the support surface 3a more stable.

[0050] When performing plasma etching, the dielectric substrate 11 is heated on the placement surface 11s side in response to the heat generation of the wafer W and cooled from the back surface 11p side by the metal base 3. The dielectric substrate 11 is heated and cooled from both sides in the plate thickness direction, and there is a possibility that warpage occurs so as to be convex on the wafer W side (upper side). If the dielectric substrate 11 warps so as to be convex on the wafer W side, there is a concern that the true contact area with the support surface 3a at the center of the back surface 11p of the dielectric substrate 11 decreases compared to the true contact area on the outside. According to the present embodiment, since the electrostatic chuck plate 2 also adsorbs the metal base 3, the warpage of the dielectric substrate 11 is suppressed, and the true contact area between the back surface 11p and the support surface 3a can be made uniform as a whole. Thereby, the non-uniformity of the heat transfer efficiency between the dielectric substrate 11 and the metal base 3 due to warpage can be suppressed.

[0051] Note that the case where the electrostatic chuck plate 2 of the present embodiment adsorbs the wafer W and the metal base 3 by applying a voltage to one adsorption electrode 13 has been described. However, the electrostatic chuck plate 2 may have an adsorption electrode for adsorbing the wafer W and an adsorption electrode for adsorbing the metal base 3, respectively.

[0052] As shown in FIG. 2, a positioning mechanism 7 is provided between the dielectric substrate 11 and the metal base 3. The positioning mechanism 7 suppresses displacement of the dielectric substrate 11 with respect to the support surface 3a in the plane direction of the support surface 3a.

[0053] As described above, in the electrostatic chuck device 1, in order to allow relative displacement between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3, the back surface 11p and the support surface 3a are joined by intermolecular forces. The joining of the back surface 11p and the support surface 3a by intermolecular forces is set to a bonding force that causes relative displacement between the back surface 11p and the support surface 3a when a stress equal to or greater than a certain level in the plane direction is applied between the back surface 11p and the support surface 3a. For this reason, when the dielectric substrate 11 and the metal base 3 are joined by intermolecular forces, there is a concern about displacement of the dielectric substrate 11 with respect to the metal base 3, such as rotation of the dielectric substrate 11 in the circumferential direction with respect to the metal base 3. If the dielectric substrate 11 is displaced with respect to the metal base 3, it becomes difficult to position the wafer W mounted on the mounting surface 11s.

[0054] The positioning mechanism 7 of the present embodiment allows relative displacement caused by the difference in thermal expansion between the back surface 11p and the support surface 3a in the plane direction of the support surface 3a, while suppressing displacement in a direction orthogonal to the relative displacement. For this reason, it is possible to easily position the wafer W mounted on the mounting surface 11s.

[0055] In the present embodiment, the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3 are each circular in plan view. The back surface 11p and the support surface 3a expand symmetrically with respect to the center of each surface. That is, the back surface 11p and the support surface 3a are relatively displaced in the radial direction of the center C of the support surface 3a due to the difference in thermal expansion efficiency. The positioning mechanism 7 of the present embodiment allows movement of the dielectric substrate 11 in the radial direction of the center of the support surface 3a in the plane direction of the support surface 3a, while suppressing displacement of the dielectric substrate 11 in the circumferential direction.

[0056] The positioning mechanism 7 has a plurality of positioning pins (protrusions) 7a that protrude downward from the back surface 11p of the dielectric substrate 11, and a plurality of recesses 7b provided on the support surface 3a of the metal base 3. The positioning pins 7a are inserted into holding holes 11h provided in the back surface 11p of the dielectric substrate 11 and held by the dielectric substrate 11. The positioning pins 7a protrude downward from the back surface 11p of the dielectric substrate 11. The recesses 7b are recessed downward with respect to the support surface 3a. One positioning pin 7a is inserted into each recess 7b.

[0057] FIG. 3 is a plan view of the metal base 3. As shown in FIG. 3, the plurality of recesses 7b are arranged at equal intervals along the circumferential direction of the center C of the support surface 3a. The plurality of recesses 7b extend along the radial direction of the center C of the support surface 3a. In the present embodiment, the recess 7b has an elongated hole shape extending along the radial direction.

[0058] The recess 7b has, in plan view, a pair of side surfaces 7c that extend parallel to each other and face each other, and a pair of semi-circular arc surfaces 7d that connect the pair of side surfaces 7c. On the other hand, the positioning pin 7a has a columnar shape and is disposed between the pair of side surfaces 7c. The distance between the pair of side surfaces 7c is substantially the same as or slightly larger than the diameter of the positioning pin 7a. The pair of side surfaces 7c guide the positioning pin 7a. Thereby, the positioning mechanism 7 suppresses the positional deviation of the dielectric substrate 11 in the circumferential direction while allowing the movement of the dielectric substrate 11 in the radial direction of the center C of the support surface 3a.

[0059] In the positioning mechanism 7 of the present embodiment, the case where the positioning pins 7a are provided on the back surface 11p and the positioning pins 7a are provided on the support surface 3a has been described. However, even in the case where the positioning pins 7a are provided on the support surface 3a and the recesses 7b are provided on the back surface 11p, the same effect can be obtained. That is, the positioning mechanism 7 only needs to have a plurality of protrusions (positioning pins 7a in the present embodiment) that protrude from one of the back surface 11p and the support surface 3a to the other side, and a plurality of recesses 7b provided on the other side into which the protrusions are inserted.

[0060] In addition, the electrostatic chuck device 1 of the present embodiment is provided with a power supply terminal 16 that extends across between the dielectric substrate 11 and the metal base 3. In the present embodiment, the power supply terminal 16 is disposed at the center C of the support surface 3a. For this reason, the power supply terminal 16 functions as a part of the positioning mechanism 7 that aligns the center C of the support surface 3a with the center of the dielectric substrate 11.

[0061] Although omitted in this embodiment, the electrostatic chuck device 1 may be provided with lift pins that penetrate the dielectric substrate 11 and the metal base 3 in the vertical direction. The lift pins are connected to an operating mechanism that drives the lift pins in the vertical direction at the lower ends. The lift pins extend upward from the mounting surface 11s of the dielectric substrate 11 to separate the wafer W from the mounting surface 11s. In this case, the through holes of the dielectric substrate 11 and the metal base 3 through which the lift pins pass are made large enough to accommodate the relative displacement amount caused by the difference in the thermal expansion coefficients of the dielectric substrate 11 and the metal base 3. As described above, a positioning mechanism 7 is provided between the dielectric substrate 11 and the metal base 3, and the positioning of the dielectric substrate 11 and the metal base 3 is performed in the plane direction of the support surface 3a. For this reason, it is possible to prevent the lift pins from interfering with the dielectric substrate 11 and the metal base 3. Further, instead of the positioning pins 7a described above, cylindrical insulators that are inserted through the lift pins and are also inserted into the through holes of the dielectric substrate 11 and the metal base 3 may be used.

[0062] As shown in FIG. 2, a pair of jig insertion recesses 8 are provided at the outer edge of the support surface 3a. The jig insertion recesses 8 are recessed downward with respect to the support surface 3a and are also recessed radially inward with respect to the outer peripheral surface of the metal base 3. The jig insertion recesses 8 have inclined surfaces 8a that incline downward as they go radially outward of the support surface 3a. In the jig insertion recesses 8, the vertical gap between the dielectric substrate 11 and the metal base 3 gradually increases as it goes radially outward of the metal base 3.

[0063] The electrostatic chuck plate 2 is replaced when the wear of the mounting surface 11s progresses. In this case, the operator detaches the electrostatic chuck plate 2 from the support surface 3a of the metal base 3. The dielectric substrate 11 and the metal base 3 of the present embodiment are joined by intermolecular forces. Therefore, when detaching the electrostatic chuck plate 2 from the metal base 3, it is necessary to separate the back surface 11p and the support surface 3a with a force greater than the intermolecular force acting between the dielectric substrate 11 and the metal base 3.

[0064] According to the present embodiment, a jig insertion recess 8 is provided at the outer edge of the support surface 3a. Further, a dedicated plate replacement jig 9 is attached to the electrostatic chuck device 1. The plate replacement jig 9 is thinner toward the tip side. The operator who replaces the electrostatic chuck plate 2 inserts the tip of the plate replacement jig 9 into any one of the two jig insertion recesses 8 and tilts the base of the plate replacement jig 9 downward. Due to the effect of the lever principle, a large force is applied between the back surface 11p of the dielectric substrate 11 and the support surface 3a of the metal base 3, and the back surface 11p and the support surface 3a can be separated. According to the present embodiment, the replacement of the electrostatic chuck plate 2 can be performed smoothly.

[0065] In the present embodiment, the jig insertion recess 8 is provided in the support surface 3a, but the jig insertion recess 8 may be provided in the back surface 11p. That is, the jig insertion recess 8 may be provided at the outer edge of at least one of the back surface 11p and the support surface 3a.

[0066] As described above, various embodiments of the present invention have been described. However, each configuration and their combinations in each embodiment are examples, and additions, omissions, substitutions, and other changes of the configuration are possible without departing from the spirit of the present invention. Further, the present invention is not limited by the embodiments.

Explanation of Reference Numerals

[0067] 1...Electrostatic chuck device, 2...Electrostatic chuck plate, 3...Metal base, 3a...Support surface, 5...Cooling device, 7...Positioning mechanism, 7a...Positioning pin (protrusion), 7b...Recess, 8...Fixture insertion recess, 11...Dielectric substrate, 11p...Back surface, 11s...Placement surface, 13...Suction electrode, C...Center, W...Wafer

Claims

1. A dielectric substrate having a mounting surface on which a wafer is mounted, and an electrostatic chuck plate having a suction electrode located inside the dielectric substrate, A metal base that supports the back surface of the dielectric substrate located on the opposite side of the mounting surface on a support surface, The true contact area between the back surface and the support surface is 0.005% or more and 40% or less, The dielectric substrate and the metal base are joined to each other by intermolecular forces, A positioning mechanism for suppressing displacement of the dielectric substrate with respect to the support surface is provided between the dielectric substrate and the metal base in the plane direction of the support surface, An electrostatic chuck device.

2. A dielectric substrate having a mounting surface on which a wafer is mounted, and an electrostatic chuck plate having a suction electrode located inside the dielectric substrate, A metal base that supports the back surface of the dielectric substrate located on the opposite side of the mounting surface on a support surface, The dielectric substrate and the metal base are joined to each other by intermolecular forces, A positioning mechanism for suppressing displacement of the dielectric substrate with respect to the support surface is provided between the dielectric substrate and the metal base in the plane direction of the support surface, The positioning mechanism is A plurality of convex portions protruding from one of the back surface and the support surface to the other side, A plurality of concave portions provided on the other side, into which the convex portions are respectively inserted, The plurality of concave portions extend along a radial direction with respect to the center of the support surface, An electrostatic chuck device.

3. A dielectric substrate having a mounting surface on which a wafer is mounted, and an electrostatic chuck plate having a suction electrode located inside the dielectric substrate, A metal base that supports the back surface of the dielectric substrate located on the opposite side of the mounting surface on a support surface, A jig insertion concave portion that opens radially outward is provided at least at an outer edge of one of the back surface and the support surface, The dielectric substrate and the metal base are joined to each other by intermolecular forces, A positioning mechanism for suppressing displacement of the dielectric substrate with respect to the support surface is provided between the dielectric substrate and the metal base in the plane direction of the support surface, An electrostatic chuck device.

4. By applying a voltage to the suction electrode, the electrostatic chuck plate adsorbs the metal base to the back surface, The electrostatic chuck device according to any one of Claims 1 to 3.

5. Further provided is a cooling device that contacts a surface of the metal base opposite to the support surface. The cooling device has a heat pipe structure. The electrostatic chuck device according to any one of claims 1 to 4.

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