Electrostatic chucking device

Abstract

The electrostatic chucking device comprises: a first substrate that is formed with a dielectric material and supports a plate-shaped sample; a second substrate; and an electrostatic attraction electrode that is sandwiched between the first substrate and the second substrate. The relative permittivity of the first substrate is 10 or greater. The first substrate has a plurality of protrusions that are provided so as to protrude upward from the upper surface of the first substrate and that support the plate-shaped sample at the upper end. The upper surface of the first substrate is continuous from the inner circumferential side of the first substrate to the outer edge of the first substrate in a plan view. A plan view cross-sectional area of the plurality of protrusions is 5% or less of a plan view cross-sectional area of the first substrate. When assuming the smallest circumscribed circle while viewing the protrusions in a plan view, the diameter of the circumscribed circle is 0.5 mm or less, the separation distance between adjacent protrusions is 20 times or more the diameter of the circumscribed circle, and the distance from the outermost protrusion that is closest to the outer edge of the first substrate among the plurality of protrusions to the outer edge of the first substrate is less than the separation distance.

Description

Electrostatic Chuck Device

[0001] This application claims priority to Japanese Patent Application No. 2024-051452, filed March 27, 2024, the contents of which are incorporated herein by reference.

[0002] In the semiconductor manufacturing process, a plate-shaped sample (wafer) fixed on a sample stage is subjected to plasma processing to process the wafer surface, for example, to form a wiring structure. After processing, the wafer is inspected using an inspection device to check for surface scratches and the presence of dust on the surface, and whether the formed wiring structure meets the design requirements.

[0003] In such wafer inspections, an electrostatic chuck device that can easily fix and hold a wafer is used. The electrostatic chuck device has a base body, one main surface of which is a mounting surface on which a wafer is placed, and an electrostatic attraction electrode that generates an electrostatic force (Coulomb force) between the base body and the wafer placed on the mounting surface (see, for example, Patent Document 1). The base body is made of a ceramic plate, which is a dielectric material.

[0004] International Publication No. 2019 / 245791

[0005] When a wafer is held by a conventional electrostatic chuck for a long period of time, the dielectric substrate can become charged. Possible causes of charging include the electron beam used for inspection, secondary electrons generated by the potential difference between the wafer and the holding electrode, and frictional charging caused by repeatedly placing and removing the wafer.

[0006] A charged substrate cancels out the Coulomb force generated by the electrostatic attraction electrode, reducing the wafer attraction force, which can result in insufficient wafer fixation in an electrostatic chuck device with a charged substrate.

[0007] Furthermore, when the application of the electrostatic attraction electrode is stopped and the wafer is to be transferred, the charged substrate continues to attract the wafer due to the charge remaining on the substrate, which may hinder the removal of the wafer from the mounting surface. If the wafer is to be removed after the use of the electrostatic chuck device by discharging the charge from the substrate, the time required for the inspection work will be extended due to the discharging operation, and the work efficiency will be reduced.

[0008] In this way, if the base becomes charged, proper operation is hindered both when the wafer is being attracted (during inspection, etc.) and when the wafer is not being attracted (after inspection, etc.), and therefore improvement was required.

[0009] The present invention has been made in view of the above circumstances, and has an object to provide an electrostatic chuck device in which charging of a base constituting a mounting surface is suppressed.

[0010] In order to solve the above problems, one aspect of the present invention includes the following apparatus.

[0011] [1] An electrostatic chuck device comprising: a first substrate made of a dielectric material and supporting a plate-shaped sample; a second substrate; and an electrostatic attraction electrode sandwiched between the first substrate and the second substrate, wherein the first substrate has a relative dielectric constant of 10 or more; the first substrate has a plurality of protrusions that protrude upward from an upper surface of the first substrate and support the plate-shaped sample at their upper ends; the upper surface of the first substrate is continuous from an inner periphery of the first substrate to an outer edge of the first substrate in a planar view; the planar view areas of the plurality of protrusions are 5% or less of the planar view area of ​​the first substrate; when a smallest circumscribing circle of the protrusions is assumed in a planar view, the diameter of the circumscribing circle is 0.5 mm or less; the separation distance between adjacent protrusions is 20 times or more the diameter of the circumscribing circle; and the distance from an outermost protrusion of the plurality of protrusions that is closest to the outer edge of the first substrate to the outer edge of the first substrate is shorter than the separation distance.

[0012] [2] The electrostatic chuck device according to [1], wherein the height of the convex portion from the upper surface is 15 μm or less.

[0013] [3] The electrostatic chuck device according to [1] or [2], wherein the protrusion is circular in plan view.

[0014] [4] An electrostatic chuck device according to any one of [1] to [3], further comprising: a charge removal portion provided to protrude from the upper surface of the first substrate at the same height as the convex portion; the charge removal portion including: a conductive member that is embedded in the first substrate and the second substrate, penetrates the first substrate and the second substrate in the thickness direction, and protrudes upward from the upper surface of the first substrate; and a conductive film provided to cover an upper end of the conductive member.

[0015] [5] An electrostatic chuck device according to any one of [1] to [4], wherein the first substrate is dug below the top surface of the first substrate and has a groove portion extending in the surface direction.

[0016] According to the present invention, it is possible to provide an electrostatic chuck device in which charging of the base constituting the mounting surface is suppressed.

[0017] Fig. 1 is a schematic perspective view showing a preferred example of an electrostatic chuck device 1 according to this embodiment. Fig. 2 is a partial enlarged view of the electrostatic chuck device 1. Fig. 3 is a schematic cross-sectional view of the electrostatic chuck device 1. Fig. 4 is a schematic partial plan view of the electrostatic chuck device 1 showing details of a conductive film 32. Fig. 5 is a schematic enlarged view of the position of the symbol α in Fig. 4. Fig. 6 is a schematic explanatory view showing an electrostatic chuck device according to a modified example.

[0018] A preferred example of an electrostatic chuck device according to this embodiment will be described below with reference to FIGS. 1 to 6. In all of the following drawings, the dimensions and proportions of the components have been appropriately changed to make the drawings easier to understand. The following description is provided specifically to facilitate a better understanding of the spirit of the invention, and does not limit the present invention unless otherwise specified. For example, unless otherwise specified, conditions such as shape, size, number, material, quantity, type, position, and proportion may be changed, added, or omitted as necessary.

[0019] In the following explanation, an xyz Cartesian coordinate system is set, and the positional relationships of the components are explained with reference to this xyz Cartesian coordinate system. Here, a predetermined direction in a horizontal plane is defined as the x-axis direction, a direction perpendicular to the x-axis direction in the horizontal plane is defined as the y-axis direction, and a direction perpendicular to both the x-axis and y-axis directions (i.e., the vertical direction) is defined as the z-axis direction.

[0020] Fig. 1 is a schematic perspective view showing a preferred example of an electrostatic chuck device 1 according to this embodiment. Fig. 2 is a partially enlarged view of the electrostatic chuck device 1. Fig. 3 is a schematic cross-sectional view of the electrostatic chuck device 1, taken along line III-III in Fig. 2 .

[0021] 1 to 3, an electrostatic chuck device 1 of this embodiment includes a base 10 that supports a plate-like sample (wafer W), and an electrostatic attraction electrode 20 provided inside the base 10. The electrostatic chuck device 1 is preferably used to fix and hold the wafer W after processing when inspecting the wafer W for the presence or absence of scratches on the surface or dust adhering to the surface, and for whether the formed wiring structure satisfies design requirements.

[0022] In the electrostatic chuck device 1, grooves 19 are formed in two locations on the base 10. The grooves 19 are dug downward (in the −z direction) from the upper surface 10a of the base 10 and extend in the surface direction (in the x direction in FIG. 1 ). Support portions X of a transfer fork used to transfer the wafer W are inserted into the grooves 19, and the wafer W is placed on the base 10 before inspection and removed after inspection.

[0023] In conventional electrostatic chuck devices, the base 10 may become charged, causing problems. Specifically, in conventional electrostatic chuck devices used for the above-described applications, the base 10 may become charged as the wafer W is repeatedly inspected, causing problems in fixing and removing the wafer W. In contrast, in the electrostatic chuck device 1 of this embodiment, the above-described problems are solved by devising a configuration for the protrusion 15. Each configuration will be described below in order.

[0024] <<Base>> The base 10 is formed of a dielectric material and supports the wafer W. As shown in Figures 2 and 3, the base 10 has a plurality of protrusions 15 that protrude upward (in the +z direction) from the upper surface 10a and support the wafer W at their upper ends. An imaginary plane connecting the upper ends of the plurality of protrusions 15 corresponds to the mounting surface that supports the wafer W.

[0025] As described above, the surface of the base 10 on which the convex portions 15 are formed, in other words, the bottom surface of the convex portions 15 as viewed from the top end thereof, is defined as the "top surface 10a," and the convex portions 15 are expressed as protruding upward from the top surface 10a. The groove portions 19 described above are also expressed as having a structure dug downward from the top surface 10a. The arrangement of the convex portions 15 and the depth of the groove portions 19 are set arbitrarily as needed. For example, the convex portions 15 may be arranged on a plurality of concentric circles arranged at equal intervals around the center of the substrate, or may be arranged at intervals from each other in a lattice pattern.

[0026] The protrusions 15 have a cylindrical or truncated cone shape, and the cross section along the upper surface 10a is circular. The shape of the protrusions 15 is not limited to a cylindrical or truncated cone shape. Furthermore, the cross-sectional shape of the protrusions 15 is not limited to a circular shape, and may be an ellipse or a polygonal shape such as a triangle or a rectangle.

[0027] Regardless of the cross-sectional shape of the protrusions 15, assuming the smallest circumscribing circle when the protrusions 15 are viewed in plan, the diameter of the circumscribing surface is 0.5 mm or less. It may be 0.50 mm or less, 0.45 mm or less, 0.40 mm or less, 0.30 mm or less, or 0.20 mm or less. The lower limit of the diameter of the circumscribing surface can be selected arbitrarily and may be, for example, 0.005 mm or more, 0.01 mm or more, or 0.1 mm or more. Furthermore, the total area of ​​the multiple protrusions 15 in plan view is 5% or less of the area of ​​the first substrate 11 in plan view. It may be 4.5% or less, 4% or less, 3% or less, 2% or less, or 1% or less. The lower limit can be selected arbitrarily and may be, for example, 0.01% or more, 0.05% or more, or 0.1% or more. Since the protrusions 15 have such a size, the contact area between the protrusions 15 and the wafer W is small, and frictional charging between the protrusions 15 and the wafer W is suppressed.

[0028] The height of the protrusions 15 (height from the upper surface 10a to the upper end 15a of the protrusions 15) is preferably 15 μm or less. It may be 13 μm or less, 10 μm or less, 8 μm or less, or 6 μm or less. The lower limit of the height of the protrusions 15 can be selected arbitrarily and may be, for example, 0.5 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, or 5 μm or more.

[0029] (First Base, Second Base) The base 10 has a first substrate 11 and a second substrate 12. The first substrate 11 and the second substrate 12 are stacked in the thickness direction.

[0030] The first substrate 11 has a circular plate shape in a plan view. The upper surface of the first substrate 11 is the upper surface 10a of the base body 10. The first substrate 11 is made of a ceramic material, which is a dielectric material.

[0031] The relative dielectric constant of the first substrate 11 is 10 or more, more preferably 11 or more, and even more preferably 12 or more. It may be 13 or more, 15 or more, 20 or more, 25 or more, or 30 or more. The upper limit of the relative dielectric constant of the first substrate 11 is selected arbitrarily, and may be, for example, 1000 or less, 750 or less, 500 or less, 300 or less, 100 or less, or 50 or less.

[0032] The ceramic material constituting the first substrate 11 is, for example, aluminum oxide (Al ２ O ３ ) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al ２ O ３ A sintered body of silicon carbide (SiC) composite is preferably used.

[0033] The second substrate 12 has a circular plate shape in a plan view and is made of a ceramic material.

[0034] The ceramic material constituting the second substrate 12 is, for example, Al. ２ O ３ Sintered body, AlN sintered body, Al ２ O ３ The second substrate 12 may be made of the same material as the first substrate 11, or may be made of a material different from that of the first substrate 11.

[0035] The second substrate 12 may be made of a single sintered body, or may be made by stacking and bonding a plurality of sintered bodies in the thickness direction. In this case, the plurality of sintered bodies may be made of different ceramic materials.

[0036] (Electrostatic Adsorption Electrode) The electrostatic adsorption electrode 20 is in contact with the lower surface of the first substrate 11 and is provided between the first substrate 11 and the second substrate 12. The area of ​​the electrostatic adsorption electrode 20 in a plan view is 80% or more of the area of ​​the base 10 in a plan view. If necessary, it may be 83% or more, 85% or more, 90% or more, 93% or more, or 95% or more. The shape of the electrostatic adsorption electrode 20 in a plan view can be selected arbitrarily. The electrostatic adsorption electrode 20 may be formed from, for example, silver, molybdenum, tungsten, a conductive ceramic containing any of these, or a conductive adhesive containing any of these, but is not limited to these examples.

[0037] The electrostatic attraction electrode 20 is preferably a composite of an insulating material and a conductive material. The insulating material contained in the electrostatic attraction electrode 20 is not particularly limited, but may be, for example, Al. ２ O ３ , AlN, silicon nitride (Si ３ N ４ ), yttrium (III) oxide (Y ２ O ３ ), yttrium aluminum garnet (YAG) and SmAlO ３ The conductive material is not particularly limited and can be selected arbitrarily. For example, conductive organic materials containing silver (Ag) (silver paste, etc.), molybdenum carbide (Mo), ２ It is preferable that the material is at least one selected from the group consisting of molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0038] A power supply terminal (not shown) is connected to the electrostatic attraction electrode 20. The power supply terminal applies a voltage to the electrostatic attraction electrode 20. When the voltage is applied, the electrostatic attraction electrode 20 generates an electrostatic attraction force that holds the wafer W supported by the protrusions 15.

[0039] (Adhesive Layer) The adhesive layer 25 is provided between the first substrate 11 and the second substrate 12 to bond the first substrate 11 and the second substrate 12 together.

[0040] The material of the adhesive layer 25 can be selected arbitrarily as needed, and examples thereof include silicone resin, acrylic resin, epoxy resin, and polyimide resin.

[0041] The adhesive layer 25 may be formed by applying a paste-like adhesive to one surface of the second substrate 12 and hardening it, or by placing a sheet-like adhesive between the first substrate 11 and the second substrate 12 and hardening it.

[0042] (Discharger) The discharger 30 has a function of removing electric charges that accumulate on the base 10 due to repeated use (such as inspection of the wafer W). The discharger may be provided so as to protrude from the upper surface 10a of the base 10. The discharger 30 may be provided so as to protrude from the upper surface 10a of the base 10 at the same height as the protrusions 15.

[0043] The static eliminator 30 has a conductive member 31 and a conductive film 32. The conductive film 32 of the static eliminator 30 may cover the convex portions 15. The number and positions of the convex portions 15 covered by the conductive film 32 can be selected arbitrarily.

[0044] (Conductive Member) The conductive member 31 is formed of a conductive material and is embedded in the base 10. The conductive member 31 is connected to a GND potential. Examples of the conductive material include a conductive organic material containing silver (Ag) (such as silver paste), molybdenum carbide (Mo), and the like. ２ Examples of suitable materials include, but are not limited to, molybdenum (Mo), tungsten carbide (WC), tungsten (W), tantalum carbide (TaC), tantalum (Ta), silicon carbide (SiC), carbon black, carbon nanotubes, and carbon nanofibers.

[0045] The conductive member 31 penetrates the base 10 in the thickness direction (z direction) and protrudes upward from the upper surface 10a of the base 10 to the same height as the protrusions 15. The wafer W is easily charged due to charges from the electron beam, secondary electrons generated by the potential difference between the wafer W and the electrostatic attraction electrode 20, friction between the wafer W and the base 10, and the like. Because the conductive member 31 protrudes as described above, it is easy to electrically connect to the wafer W via the conductive film 32, and the wafer W can be easily de-electrified.

[0046] 3 , the conductive member 31 has a first conductive member 311 embedded in the first substrate 11 and a second conductive member 312 embedded in the second substrate 12. The first conductive member 311 and the second conductive member 312 are electrically connected to each other to form the conductive member 31.

[0047] The first conductive member 311 is a cylindrical member having a through hole 311x penetrating in the z direction, and the second conductive member 312 is a cylindrical member having a through hole 312x penetrating in the z direction. The through holes 311x and 312x have the same central axis and are connected to each other, forming a through hole 31x that penetrates the conductive member 31 in the thickness direction of the base 10. When the first conductive member 311 and the second conductive member 312 have a cylindrical outer shape, their outer diameters can be selected arbitrarily. For example, the outer diameter of the second conductive member 312 may be 1.0 to 10.0 times, 1.3 to 7.0 times, 1.5 to 5.0 times, 2.0 to 4.5 times, or 2.5 to 4.0 times the outer diameter of the first conductive member 311.

[0048] The static eliminator 30 has a static eliminator protrusion 33 that surrounds the conductive member 31 in a plan view. As shown in FIG. 2 , the static eliminator protrusion 33 is provided in a circular shape that is concentric with the conductive member 31 in a plan view. The static eliminator protrusion 33 may be a part of the first substrate 11. The static eliminator protrusion 33 may also have the same outer diameter as the second conductive member 312.

[0049] 3, the static eliminator convex portion 33 is provided to protrude from the upper surface 10a of the base 10 to the same height as the convex portion 15 and the conductive member 31. In other words, the thickness of the static eliminator convex portion 33 may be the same as the thickness of the convex portion 15.

[0050] Moreover, the conductive member 31 is preferably provided in the center of the base 10 in plan view (indicated by the reference numeral 31 in FIG. 1).

[0051] (Conductive Film) The conductive film 32 is provided in contact with and covers the upper end 31 a of the conductive member 31. The conductive film 32 is also in contact with and covers the upper end 33 a of the static eliminator protrusion 33, which is provided at the same height as the conductive member 31, and covers both the upper end 31 a and the upper end 33 a.

[0052] The conductive film 32 is a film formed in a predetermined pattern using a conductive material. The material of the conductive film 32 can be selected arbitrarily, and examples thereof include non-magnetic metals such as TiN, Ti, and aluminum, and compounds thereof. The conductive film 32 is obtained by forming the conductive film 32 on the base 10 using a known patterning technique using these materials. The shape of the conductive film 32 in a plan view can be selected arbitrarily, as long as a portion of the conductive film 32 covers the upper end of the conductive member 31. The conductive film 32 may be in contact only with the first substrate 11, including the convex portion, and the conductive member 31.

[0053] The conductive film 32 is electrically connected to the conductive member 31. For example, in the example shown in Fig. 3, a portion of the conductive film 32 is in direct contact with the upper end of the conductive member 31, and the other portion of the conductive film 32 extends further. With this connection, the static eliminator 30 is connected to the GND potential (ground), and static electricity can be eliminated from the members in contact with the static eliminator 30 (the conductive member 31 and the conductive film 32).

[0054] The conductive film 32 is preferably provided from the upper end 31a of the conductive member 31 to the upper surface 10a of the base 10. In this case, by making the thickness of the conductive film 32 smaller (thinner) than the height of the convex portions 15, the conductive film 32 provided on the upper surface 10a is not positioned higher than the convex portions 15, and the wafer W can be suitably supported by the convex portions 15. The thickness of the conductive film 32 can be selected arbitrarily and may be, for example, 0.0001 mm to 0.013 mm, 0.0003 mm to 0.010 mm, 0.0005 mm to 0.005 mm, or 0.001 mm to 0.003 mm. The width of the conductive film 32 can be selected arbitrarily and may be, for example, 0.5 mm to 25 mm, 1 mm to 15 mm, 2 mm to 10 mm, or 3 mm to 5 mm, but is not limited to these.

[0055] Furthermore, it is preferable that the conductive film 32 be provided from the upper end 31a of the conductive member 31 to the upper ends 15a of some of the plurality of protrusions 15. In this configuration, the base 10 and the wafer W can be neutralized at the plurality of protrusions 15 having the conductive film 32 provided on their upper ends 15a. The proportion of the number of protrusions 15 having the conductive film 32 thereon can be selected arbitrarily, and may be, for example, 5 to 8%, 8 to 15%, or 15 to 20% of the total number of protrusions 15. Note that even if there are protrusions 15 having the conductive film 32 thereon and protrusions 15 not having the conductive film 32 thereon, the thickness of the conductive film is sufficiently small compared to the height of the protrusions 15, so there is no problem in supporting the wafer W.

[0056] In such a configuration, it is preferable that the conductive film 32 is provided in a strip shape in a plan view, as shown in FIGS.

[0057] The conductive film 32 has a shape that combines a plurality of first films 321 and a plurality of second films 322. The first films 321 have a common center and are provided in a circular or arc shape. The second films 322 are connected to the plurality of first films 321.

[0058] In a plan view, the area of ​​the conductive film 32 is 20% or less of the area of ​​the base 10. If necessary, it may be 18% or less, 15% or less, 13% or less, 10% or less, 5% or less, or 3% or less. By forming the conductive film 32 with the above area and forming the electrostatic attraction electrode 20 to 80% or more of the area of ​​the base 10 as described above, the wafer W can be attracted appropriately even when the base 10 is neutralized by the conductive film 32. In other words, the wafer W can be attracted appropriately while preventing phenomena caused by undesirable charging of the base. In other words, the wafer can be fixed more efficiently, resulting in improved work efficiency. The overlapping ratio between the electrostatic attraction electrode 20 and the conductive film 32 in a plan view can be freely selected. For example, in a plan view, 0 to 10% of the conductive film 32 may overlap with the electrostatic attraction electrode 20, preferably 0.3 to 7%, more preferably 0.5 to 5%, and even more preferably 0.7 to 2%. If necessary, the conductive film 32 and the electrostatic attraction electrode 20 do not have to overlap.

[0059] Fig. 4 is a partial plan view of the electrostatic chuck device 1 showing details of the conductive film 32. Fig. 5 is an enlarged view of the position indicated by the symbol α in the figure. As shown in Figs. 4 and 5, the conductive film 32 has a first film 321A provided on the outermost periphery in a plan view, and first films 321B, 321C, and 321D provided concentrically with the base 10 and the first film 321A.

[0060] A second film 322A extending in the x-direction is provided at the center of the substrate 10 in a plan view, and the second film 322A connects the first films 321A to 321D at the center of the substrate 10. In a plan view, the second film 322A is a substantially linear film passing through the center of the substrate and preferably has a doughnut-shaped portion in its center. The length of the second film 322A is substantially equal to the diameter of the substantially circular first film 321A. As shown in FIG. 2 , the second film 322A overlaps the conductive member 31, the static eliminator convex portion 33, and the multiple convex portions 15 arranged in the x-direction in a plan view. The second film 322A has a first portion 322x provided with an equal width and a second portion 322y formed to overlap the static eliminator convex portion 33 and bulge outward from the static eliminator convex portion 33.

[0061] Further, second films 322B and 322C are provided parallel to the second film 322A along the groove portion 19, and an arc-shaped second film 322D is provided connecting the second films 322B and 322C and the first film 321B.

[0062] (Conductive film on peripheral edge of substrate) The first film 321A and the second films 322B, 322C, and 322D are connected to each other and form a peripheral film provided along the outer edge 10b of the base body 10 in a plan view. The first film 321A is a part of the peripheral film.

[0063] The peripheral films (first film 321A, second films 322B, 322C, 322D) are provided inward from the outer edge 10b of the base body 10 in plan view. The number of peripheral films can be selected arbitrarily.

[0064] The upper surface 10a of the base 10 is continuous from the inner periphery of the base 10 to the outer edge 10b of the base 10 in a plan view. The upper surface 10a may be connected to the outer edge 10b of the base 10 over the entire periphery, or a protrusion 15 may be provided on a part of the outer edge 10b. A protrusion 15 may be provided between the peripheral film and the outer edge 10b of the base 10.

[0065] As shown in FIG. 5 , the separation distance W1 between adjacent convex portions 15 is 20 times or more the diameter of the convex portions 15 in a plan view (the diameter of the circumscribing circle of the convex portions 15 in a plan view). It may be 25 times or more, 30 times or more, or 40 times or more. The upper limit can be arbitrarily selected, and may be, for example, 300 times or less, 200 times or less, 100 times or less, or 70 times or less. Furthermore, the distance W2 from the outermost convex portion 15A, which is closest to the outer edge 10b of the first substrate 11, to the outer edge 10b of the first substrate 11 is shorter than the separation distance W1. For example, the distance W2 may be 90% or less, 80% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less of the separation distance W1. The lower limit of the distance W2 can be selected arbitrarily, and may be, for example, 0.1% or more, 1% or more, 3% or more, or 5% or more of the separation distance W1, but is not limited to these.

[0066] The distances Wa, Wb, and Wc between adjacent first films 321A-321D in the radial direction are preferably 40 mm or less. They may be 35 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less. The radius Wd of the circular first film 321D is preferably 40 mm or less. It may be 35 mm or less, 30 mm or less, 20 mm or less, or 10 mm or less. The inventors' studies have confirmed that static electricity can be suitably eliminated if the conductive film 32 is within a range of 40 mm from the conductive film 32 in a plan view. Therefore, if the distance between the first films is 40 mm or less and the radius of the innermost first film 321D is 40 mm or less, static electricity can be suitably eliminated by the conductive film formed.

[0067] The conductive member 31 is preferably provided in an area AR surrounded by the innermost first film 321D among the plurality of first films 321. In the drawing, this corresponds to the conductive member indicated by the reference symbol 31A. By arranging the conductive member 31 in this manner, it is possible to neutralize the base body 10 evenly via the conductive film 32. It is preferable that the area AR coincides with the center of the base body 10 in a plan view.

[0068] The conductive member 31 may be provided at a position where conductive films intersect, for example, at a position where the first film 321 and the second film 322 intersect (for example, the position A in FIG. 4). The conductive member 31 provided at such a position collects electric charges transmitted from both the first film 321 and the second film 322, enabling efficient neutralization. The number of conductive members 31 can be selected arbitrarily.

[0069] (Pin) Additionally, it is preferable that the static eliminator 30 has a pin 50 that is inserted into the through-hole 31x of the conductive member 31 and can protrude upward from the upper end of the static eliminator 30. The pin 50 may be a lift pin that pushes up the wafer W from the backside, may be electrically connected to the conductive member 31, and / or may be a static eliminator pin that is provided so as to be able to puncture an insulating layer (not shown) on the backside of the wafer W. By using the pin 50 as a static eliminator pin, it is possible to suitably eliminate the charge accumulated on the wafer W. Note that the puncture level of the pin that is provided so as to be able to puncture may be selected arbitrarily as long as it is possible to eliminate the charge.

[0070] According to the electrostatic chuck device 1 configured as described above, the charges collected via the conductive film can be suitably removed via the conductive member, thereby suppressing charging of the base constituting the mounting surface.

[0071] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0072] For example, in the present embodiment, the conductive film 32 is provided to cover the plurality of convex portions 15, but this is not limiting. The conductive film 32 may be provided from the static eliminator convex portion 33 to the upper surface 10a of the substrate 10, or may be provided only on the upper surface of the static eliminator convex portion 33. For example, the conductive film 32 does not have to cover the convex portions 15. The conductive film 32 may be provided from the conductive member 31 and the static eliminator convex portion 33 to the upper surface 10a of the base 10, or may be provided only on the upper surfaces of the conductive member 31 and the static eliminator convex portion 33. For example, the conductive film 32 may be provided from the first conductive member 311 to the upper surface 10a of the base 10, or may be provided only on the upper surface of the first conductive member 311.

[0073] Furthermore, in this embodiment, the neutralization section 30 has the neutralization section protrusion 33 that protrudes to the same height as the conductive member 31, but the neutralization section protrusion 33 does not have to be formed.

[0074] The conductive member 31 may be at the same height as the upper surface 10a and electrically connected to the conductive film 32 on the upper surface 10a (between the protrusions 15). In this case, static electricity can be removed by the plurality of protrusions 15 on which the conductive film 32 is provided.

[0075] In addition, although the present embodiment has been described in terms of the conductive member 31 being a cylindrical member, the present invention is not limited to this. The conductive member 31 may have any other configuration as long as it is electrically connected to the conductive film 32 and can neutralize the first substrate 11 and the wafer W via the conductive film 32.

[0076] For example, like the conductive member 35 shown in Fig. 6, the conductive member may be a rod-shaped (columnar) member connected to the conductive film 32. The upper end of the conductive member 35 in Fig. 6 is provided at the same height as the upper end 33a of the static eliminator convex portion 33, but it may also be at the same height as the upper surface 10a and electrically connected to the conductive film 32 on the upper surface 10a (between the convex portions 15).

[0077] Even with the static eliminator 30 having such a configuration, the effects of the present invention can be achieved.

[0078] DESCRIPTION OF SYMBOLS 1 Electrostatic chuck device 10 Base body 10a Upper surface 10b Outer edge 11 First substrate 12 Second substrate 15 Convex portion 15a, 31a, 33a Upper end 15A Outermost convex portion 19 Groove portion 20 Electrostatic attraction electrode 25 Adhesive layer 30 Discharge neutralizing portion 31 Conductive member 31A Conductive member surrounded by innermost first film 31x, 311x, 312x Through hole 32 Conductive film 33 Discharge neutralizing portion convex portion 35 Conductive member 50 Pin 311 First conductive member 312 Second conductive member 321 First film 321A, 321B, 321C, 321D Concentrically arranged first film 322, 322A, 322B, 322C, 322D Second film 322x First portion 322y Second portion A Intersection position AR Area X Support portion of conveying fork W Wafer Wa, Wb, Wc, Wd Separation distance W1 Separation distance W2 Distance α Position

Claims

1. An electrostatic chuck device comprising: a first substrate made of a dielectric material for supporting a plate-shaped sample; a second substrate; and an electrostatic chucking electrode sandwiched between the first and second substrates, wherein the relative dielectric constant of the first substrate is 10 or greater; the first substrate has a plurality of protrusions that protrude upward from an upper surface of the first substrate and support the plate-shaped sample at their upper ends; the upper surface of the first substrate is continuous from the inner periphery of the first substrate to the outer edge of the first substrate in a planar view; the planar view area of ​​the plurality of protrusions is 5% or less of the planar view area of ​​the first substrate; assuming a smallest circumscribing circle when the protrusions are viewed in a planar view, the diameter of the circumscribing circle is 0.5 mm or less; the separation distance between adjacent protrusions is 20 times or greater than the diameter of the circumscribing circle; and the distance from the outermost protrusion of the plurality of protrusions that is closest to the outer edge of the first substrate to the outer edge of the first substrate is shorter than the separation distance.

2. An electrostatic chuck device according to claim 1, wherein the height of said convex portion from said upper surface is 15 μm or less.

3. An electrostatic chuck device according to claim 1 or 2, wherein the convex portion is circular in plan view.

4. An electrostatic chuck device according to claim 1 or 2, which has a charge removal section that protrudes from the upper surface of the first substrate at the same height as the convex section, and the charge removal section has a conductive member that is embedded in the first substrate and the second substrate, penetrates the first substrate and the second substrate in the thickness direction, and protrudes upward from the upper surface of the first substrate, and a conductive film that is provided to cover the upper end of the conductive member.

5. An electrostatic chuck device according to claim 1 or 2, wherein the first substrate is provided with a groove that is dug below the top surface of the first substrate and extends in the surface direction.

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