JP7630238B2 - Retaining device - Google Patents

Description

This disclosure relates to a holding device for holding an object.

For example, Patent Document 1 discloses an electrostatic chuck as a holding device, in which multiple protrusions are formed on the adsorption surface and which is equipped with internal electrodes such as an adsorption electrode and a heater electrode. In this electrostatic chuck, a terminal pad to which power is supplied from the outside via a power supply terminal is connected to the internal electrode via a via and an intermediate conductor layer. This allows power to be supplied from an external power source to the internal electrode via the power supply terminal, the terminal pad, the via, and the intermediate conductor layer.

JP 2017-228361 A

However, in the above electrostatic chuck, surface processing such as polishing and blasting is performed to form multiple protrusions on the adsorption surface, which reduces the thickness of the insulating layer between the internal electrode and the adsorption surface in some places, and there is a risk of dielectric breakdown occurring in the areas where the thickness is reduced. In particular, in the area where the internal electrode is connected to the via, the via pushes up the internal electrode, causing the internal electrode to rise toward the adsorption surface, further reducing the thickness of the insulating layer and making dielectric breakdown more likely to occur.

Here, if the thickness of the insulating layer on the attracting surface side is increased, the insulation properties are improved and it is possible to prevent the occurrence of dielectric breakdown. However, if the thickness of the insulating layer on the attracting surface side is increased, and if the internal electrode is a chuck electrode, the distance between the chuck electrode and the object increases, and the chucking force for holding the object decreases.

Therefore, this disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can improve insulation and prevent a decrease in suction force.

In order to solve the above problems, one aspect of the present disclosure is to
A holding device for holding an object on the first surface of the plate-like member, the holding device comprising: a plate-like member having a first surface and a second surface provided on an opposite side to the first surface in a first direction; an internal electrode located closest to the first surface among electrodes provided inside the plate-like member; and a conductive member connected to the internal electrode extending in the first direction, the holding device comprising:
A plurality of protrusions are formed on the first surface,
the internal electrode is formed across the plurality of protrusions when viewed from the first direction,
the conductive member is disposed so as to overlap the protrusion when viewed from the first direction,
The conductive members are characterized in that they are a plurality of vias connected to the internal electrodes .

In this holding device, the conductive member is arranged so as to overlap the convex portion when viewed from the first direction (top view). Here, "overlapping the convex portion" includes the case where the conductive member is completely contained within the convex portion when viewed from the top, as well as the case where a part of the conductive member overlaps the convex portion. As a result, the arrangement portion of the conductive member connected to the internal electrode, where insulation breakdown is most likely to occur, is arranged so as to overlap the convex portion formed on the first surface. Therefore, the thickness of the insulating layer in the arrangement portion of the conductive member is not reduced by the surface processing of the first surface performed to form the convex portion. Therefore, it is possible to improve the insulation and prevent the occurrence of insulation breakdown. In addition, since the thickness of the insulating layer on the first surface side does not increase, the suction force of the holding device does not decrease even if the internal electrode is a chuck electrode.

One method for forming vias is, for example, to form through-holes in a green sheet and fill the through-holes with metallization ink that will become the vias through a mask. When metallization ink is generally filled into the through-holes, the vias are formed so that they rise up by the thickness of the mask relative to the thickness of the green sheet, causing a protrusion in the via placement area (localized rise on the first surface). Therefore, if surface processing is performed on the first surface to form a protrusion, there is a risk that the thickness of the insulating layer in the via placement area will decrease.

By doing this, a convex portion is formed directly above at least two of the vias that are connected to the internal electrode, so the thickness of the insulating layer in the area where the vias connected to the internal electrode are arranged is not reduced. This improves insulation and makes it possible to prevent dielectric breakdown. Furthermore, since the thickness of the insulating layer does not increase, the suction force of the holding device is not reduced.

In the above-mentioned holding device,
The conductive members are preferably all vias connected to the internal electrodes.

By doing this, convex portions are formed directly above the positions of all the vias connected to the internal electrodes, so the thickness of the insulating layer in the positions of the vias connected to the internal electrodes does not decrease. This further improves the insulation properties, so that it is possible to reliably prevent the occurrence of dielectric breakdown. Furthermore, because the thickness of the insulating layer does not increase, the suction force of the holding device does not decrease even if the internal electrode is a chuck electrode.

In the above-mentioned holding device,
The internal electrode includes a protruding portion that protrudes toward the first surface side,
It is preferable that the protrusion overlaps the plurality of vias when viewed from the first direction.

The thickness of the insulating layer at the protruding portion of the internal electrode is thinner than at other portions, making this the area most susceptible to dielectric breakdown. Therefore, by making the protruding portion overlap with multiple vias when viewed from the first direction (top view) in this way, a convex portion is positioned directly above the protruding portion. This prevents the thickness of the insulating layer at the protruding portion of the internal electrode from decreasing, improving insulation and preventing dielectric breakdown from occurring. In addition, since the thickness of the insulating layer at the protruding portion does not increase, the suction force of the holding device does not decrease even if the internal electrode is a chuck electrode.

In the above-mentioned holding device,
It is preferable that all of the vias are arranged so as to overlap one-to-one with the protruding portion.

By doing this, compared to when multiple vias are arranged so that they overlap one convex portion, the vias are arranged farther apart, so it is possible to prevent the generation of temperature singularities (parts that become hotter than other parts) on the first surface of the plate-shaped member due to heat generation from the vias themselves. Therefore, because a convex portion is formed directly above the via arrangement portion, the thickness of the insulating layer in the via arrangement portion connected to the internal electrode does not decrease. This further improves insulation, making it possible to reliably prevent the occurrence of insulation breakdown and achieve temperature uniformity on the first surface of the plate-shaped member.

Another aspect of the present disclosure made to solve the above problem is:
A holding device for holding an object on the first surface of the plate-like member, the holding device comprising: a plate-like member having a first surface and a second surface provided on an opposite side to the first surface in a first direction; an internal electrode located closest to the first surface among electrodes provided inside the plate-like member; and a conductive member connected to the internal electrode extending in the first direction, the holding device comprising:
A plurality of protrusions are formed on the first surface,
the internal electrode is formed across the plurality of protrusions when viewed from the first direction,
the conductive member is disposed so as to overlap the protrusion when viewed from the first direction,
the conductive members are a plurality of vias connected to the internal electrodes,
a connection pad connected to the plurality of vias;
a plurality of second vias connected to the connection pads and disposed on the second surface side;
The plurality of vias and the plurality of second vias are arranged to be shifted in a second direction perpendicular to the first direction so as not to overlap when viewed from the first direction.

When the via and the second via are arranged in the same position (in a straight line in the first direction), the protruding portions of the via arrangement portion overlap, resulting in a large amount of protrusion toward the first surface side in the via arrangement portion. When this amount of protrusion becomes large, the thickness of the insulating layer decreases, making dielectric breakdown more likely to occur. By doing this, it is possible to prevent the amount of protrusion toward the first surface side of the via arrangement portion from becoming large. As a result, the thickness of the insulating layer in the via arrangement portion does not decrease, improving insulation and preventing dielectric breakdown from occurring.

In the above-mentioned holding device,
It is preferable that the second vias are arranged so as to overlap the protrusion when viewed from the first direction.

This prevents the thickness of the insulating layer from decreasing even in the area where the second via is located, improving the insulation properties even in the area where the second via is located, thereby reliably preventing the occurrence of dielectric breakdown.

According to the present disclosure, it is possible to provide a holding device that can improve insulation and prevent a decrease in suction force.

1 is a schematic perspective view of an electrostatic chuck according to an embodiment; 1 is a schematic configuration diagram of an electrostatic chuck according to an embodiment of the present invention taken along an XZ cross section; FIG. 2 is a schematic configuration diagram of an electrostatic chuck in an XY plane according to an embodiment. 4 is an enlarged cross-sectional view of a via arrangement portion and its vicinity in the ceramic member. FIG. FIG. 2 is a cross-sectional view showing a state of a ceramic member before polishing. FIG. 2 is a cross-sectional view showing the state of a ceramic member after polishing (before blasting). FIG. 13 is a diagram showing an example in which a via completely overlaps a protrusion when viewed in the Z-axis direction. 13 is a diagram showing an example in which a via partially overlaps a protrusion when viewed in the Z-axis direction. FIG. 13 is a diagram showing an example in which a plurality of vias overlap one protrusion as viewed in the Z-axis direction. FIG.

A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, a case where the holding device is applied to an electrostatic chuck that holds a semiconductor wafer will be described.

<Overall configuration of electrostatic chuck>
The electrostatic chuck of this embodiment will be described with reference to Figures 1 to 3. The electrostatic chuck 10 is a device that attracts and holds an object (e.g., a wafer W) by electrostatic attraction, and is used, for example, to fix the wafer W in a vacuum chamber of a semiconductor manufacturing device. As shown in Figure 1, the electrostatic chuck 10 has a ceramic member 41 which is a plate-shaped member, a base member 42, a bonding layer 43, and the like.

For ease of explanation, in the following description, the X, Y and Z axes are defined as shown in FIG. 1. Here, the Z axis is the axis in the direction of the central axis Ca of the electrostatic chuck 10 (the vertical direction in FIG. 1), and the X and Y axes are the radial axes of the electrostatic chuck 10. The Z axis direction (i.e., the direction of the central axis Ca) is an example of the "first direction" of the present disclosure, and the Y axis direction and the Z axis direction (i.e., the radial direction of the electrostatic chuck 10) are an example of the "second direction" of the present disclosure.

The ceramic member 41 is, for example, a disk-shaped member made of ceramics. As the ceramic, various ceramics can be used, but from the viewpoints of strength, wear resistance, plasma resistance, etc., it is preferable to use ceramics whose main component is, for example, aluminum oxide (alumina, Al ₂ O ₃ ) or aluminum nitride (AlN). Note that the main component here means the component with the highest content (for example, a component with a volume content of 90 vol % or more).

The ceramic member 41 has a diameter of, for example, about 150 mm to 300 mm, and a thickness of, for example, about 2 mm to 6 mm. The thermal conductivity of the ceramic member 41 is preferably within a range of 10 to 50 W/mK (more preferably, 18 to 30 W/mK, for example, 20 W/mK).

As shown in Figures 1 and 2, the ceramic member 41 has an adsorption surface 51, which is an upper surface, and a lower surface 52 provided on the opposite side of the adsorption surface 51 in the central axis direction of the ceramic member 41 (i.e., the Z-axis direction). This ceramic member 41 holds the wafer W on the adsorption surface 51. Note that the adsorption surface 51 is an example of the "first surface" of the present disclosure, and the lower surface 52 is an example of the "second surface" of the present disclosure.

As shown in Figs. 2 and 3, the suction surface 51 has an annular convex portion 71 formed near its outer edge, and a number of independent columnar convex portions 72 are formed inside the annular convex portion 71. The annular convex portion 71 is also called a seal band. As shown in Fig. 2, the cross section (XZ cross section) of the annular convex portion 71 has a substantially rectangular shape. The height (dimension in the Z-axis direction) of the annular convex portion 71 is, for example, about 10 µm to 20 µm. The width (dimension in the X-axis direction) of the annular convex portion 71 is, for example, about 0.5 mm to 5.0 mm.

As shown in FIG. 3, each of the protrusions 72 is substantially circular when viewed in the Z-axis direction, and is arranged at substantially equal intervals. The cross-sectional shape (XZ cross-section) of each of the protrusions 72 is substantially rectangular, as shown in FIG. 2. The height of the protrusions 72 is substantially the same as the height of the annular protrusions 71, and is, for example, about 10 μm to 20 μm. The width of the protrusions 72 (maximum diameter of the protrusions 72 when viewed in the Z-axis direction) is, for example, about 0.5 mm to 1.5 mm. The portion of the adsorption surface 51 of the ceramic member 41 inside the annular protrusions 71 where the protrusions 72 are not formed is a recess 73.

The wafer W is supported by the annular convex portion 71 and the multiple convex portions 72 on the adsorption surface 51 of the ceramic member 41 and is held by the electrostatic chuck 10. When the wafer W is held by the electrostatic chuck 10, a space exists between the surface (lower surface) of the wafer W and the adsorption surface 51 of the ceramic member 41 (more specifically, the concave portion 73 of the adsorption surface 51). An inert gas (e.g., helium gas) is supplied to this space.

2, the ceramic member 41 has a chuck electrode 53 therein. The chuck electrode 53 is, for example, substantially circular when viewed in the Z-axis direction, and is made of a conductive material (for example, tungsten, molybdenum, etc.). The chuck electrode 53 is an example of an "internal electrode" in the present disclosure. The wafer W is attracted and held on the attraction surface 51 by electrostatic attraction generated by applying a voltage to the chuck electrode 53 through the vias 81a, 81b, the connection pad 82, the via 83a, the terminal pad 84, and a power supply terminal 85 connected to the power supply (not shown). Note that a plurality of vias 81 including the vias 81a, 81b are connected to the chuck electrode 53, and a plurality of vias 83 including the via 83a are connected to the connection pad 82. The diameter of the vias 81, 83 is, for example, about 0.3 to 0.6 mm. Details of the vias 81 (81a, 81b), the via 83 (83a), etc. will be described later.

The base member 42 is formed in a cylindrical shape (more specifically, a stepped cylindrical shape formed by overlapping two cylinders of different diameters with a common central axis (the upper part of a cylindrical shape with a smaller diameter is placed on the lower part of a cylindrical shape with a larger diameter)) as shown in FIG. 1. This base member 42 is preferably formed from a metal (e.g., aluminum or an aluminum alloy), but may be made of a material other than metal.

1 and 2, the base member 42 has an upper surface 61 and a lower surface 62 provided on the opposite side to the upper surface 61 in the direction of the central axis Ca (see FIG. 3) of the base member 42 (ceramic member 41) (i.e., the Z-axis direction). The upper surface 61 is an example of the "third surface" of the present disclosure, and the lower surface 62 is an example of the "fourth surface" of the present disclosure.

The diameter of the base member 42 is, for example, about 150 mm to 300 mm at the upper section, and about 180 mm to 350 mm at the lower section. The thickness of the base member 42 (dimension in the Z-axis direction) is, for example, about 20 mm to 50 mm. The thermal conductivity of the base member 42 (assumed to be aluminum) is preferably within the range of 180 to 250 W/mK (preferably about 230 W/mK).

The base member 42 is joined to the ceramic member 41 by a joining layer 43 disposed between the lower surface 52 of the ceramic member 41 and the upper surface 61 of the base member 42. In this way, the lower surface 52 of the ceramic member 41 and the upper surface 61 of the base member 42 are thermally connected. The joining layer 43 is made of an adhesive material such as silicone resin, acrylic resin, or epoxy resin. The thickness (dimension in the Z-axis direction) of the joining layer 43 is, for example, about 0.1 mm to 1.0 mm. The thermal conductivity of the joining layer 43 is, for example, 1.0 W/mK. The thermal conductivity of the joining layer 43 (assuming silicone resin) is preferably within the range of 0.1 to 2.0 W/mK (preferably, 0.5 to 1.5 W/mK).

2, the base member 42 is provided with a refrigerant flow path 63 for flowing a refrigerant (e.g., a fluorine-based inert liquid, water, etc.). The refrigerant flow path 63 is connected to a supply port and a discharge port (not shown) provided on the lower surface 62 of the base member 42, and the refrigerant supplied to the base member 42 from the supply port flows through the refrigerant flow path 63 and is discharged from the discharge port to the outside of the base member 42. By flowing the refrigerant through the refrigerant flow path 63 in this manner, the base member 42 is cooled, and the ceramic member 41 is thereby cooled via the bonding layer 43.

<About Via>
Here, the vias 81 (81a, 81b) and the vias 83 (83a) provided in the ceramic member 41 will be described with reference to FIG. 4. As shown in FIG. 4, the vias 81 (81a, 81b) are arranged so as to extend in the Z-axis direction toward the lower surface 52 side from the chuck electrode 53, one end is connected to the chuck electrode 53, and the other end is connected to the connection pad 82. As a result, the chuck electrode 53 and the connection pad 82 are electrically connected through the vias 81 (81a, 81b). Also, the via 83 (83a) is arranged on the lower surface 52 side from the connection pad 82, one end is connected to the connection pad 82, and the other end is connected to the terminal pad 84. As a result, the connection pad 82 and the terminal pad 84 are electrically connected through the via 83 (83a). In this way, the terminal pad 84 is electrically connected to the chuck electrode 53 through the vias 83 (83a), the connection pad 82, and the vias 81 (81a, 81b). The via 83 (83a) is an example of a "second via" in the present disclosure.

The vias 81 (81a, 81b) and the vias 83 (83a) are formed by filling the through holes with metallized ink. Therefore, as shown in FIG. 4, they rise toward the suction surface 51 by the thickness of the mask used when filling the ink. Therefore, at the positions of the vias 81a, 81b, protrusions 53a, 53b are formed on the chuck electrode 53. In other words, when viewed in the Z-axis direction, the protrusions 53a, 53b overlap with the vias 81a, 81b. Furthermore, at the position of the via 83a, a protrusion 82a is formed on the connection pad 82. This protrusion 82a overlaps with the via 83a when viewed in the Z-axis direction.

Therefore, as shown in FIG. 5, the upper surface 51 of the ceramic member 41 before the convex portion 72 is formed is raised in the portions directly above the protrusions 53a, 53b, and 82a. The protrusions 53a and 53b, which are closer to the chucking surface 51, protrude more than the protrusion 82a. Before the convex portion 72 is formed, the upper surface 51 of the ceramic member 41 is polished to make it flat. After this polishing, as shown in FIG. 6, the thickness of the ceramic on the chucking surface 51 side of the protrusions 53a and 53b becomes smaller than in other portions, and the insulation in this portion decreases, which may cause dielectric breakdown.

When the convex portion 72 is formed by the blasting process performed after polishing, if the concave portion 73 is located directly above the protruding portions 53a and 53b, the thickness of the ceramic on the attracting surface 51 side becomes even smaller than the chuck electrode 53, making it more likely that dielectric breakdown will occur. Note that while it is possible to avoid dielectric breakdown by increasing the thickness of the ceramic between the chuck electrode 53 and the concave portion 73, it is practically difficult to increase the thickness of the ceramic on the attracting surface 51 side than the chuck electrode 53, since this would reduce the chucking force of the electrostatic chuck 10. Note that Figures 4 to 6 show vias 81a and 81b, which are part of the multiple vias 81 connected to the chuck electrode 53, and via 83a, which is part of the multiple vias 83 connected to the connection pad 82.

Therefore, in the electrostatic chuck 10 of this embodiment, as shown in FIG. 4, the vias 81a, 81b, and the via 83a are arranged so as to overlap the protrusion 72 when viewed in the Z-axis direction. As a result, the protrusions 53a, 53b formed on the chuck electrode 53 and the protrusion 82a formed on the connection pad 82 are arranged so as to overlap the protrusion 72 when viewed in the Z-axis direction.

Vias 81a and 81b are part of a plurality of vias 81 connected to the chuck electrode 53, and these vias 81 (81a, 81b) are located closest to the suction surface 51 among the vias provided in the ceramic member 41. Via 83a is shifted radially (in the X-axis direction or the Y-axis direction) so as not to overlap with vias 81a and 81b when viewed in the Z-axis direction. Via 83a is part of a plurality of vias 83 connected to the connection pad 82.

Here, "overlapping with the convex portion 72" means that, as shown in FIG. 7, the vias 81, 83 (or the protrusions) are completely contained within the convex portion 72 (completely overlapping), as well as the case where the vias 81, 83 (or the protrusions) partially protrude from the convex portion 72 (partially overlapping) as shown in FIG. 8. However, since the effect of preventing dielectric breakdown is smaller when there is partial overlap compared to when there is complete overlap, it is desirable that the vias 81a, 81b, 83a (or the protrusions 53a, 53b, 82a) are arranged so as to completely overlap with the convex portion 72 when viewed in the Z-axis direction.

As described above, according to the electrostatic chuck 10 of this embodiment, the vias 81a, 81b and the protrusions 53a, 53b are arranged so as to overlap the convex portion 72 when viewed in the Z-axis direction. As a result, the arrangement portion of the vias 81a, 81b connected to the chuck electrode 53, where dielectric breakdown is most likely to occur, is arranged so as to overlap the convex portion 72 formed on the adsorption surface 51. Therefore, the thickness of the ceramics (insulating layer) on the adsorption surface 51 side from the chuck electrode 53 at the arrangement portion of the vias 81a, 81b is not reduced by the surface processing (polishing and blasting) performed to form the convex portion 72. In this embodiment, the distance (thickness of the ceramics) from the upper surface of the chuck electrode 53 to the upper surface of the convex portion 72 is about 300 μm. Therefore, the insulation property of the electrostatic chuck 10 can be improved and the occurrence of dielectric breakdown can be prevented. In addition, since the thickness of the ceramics on the adsorption surface 51 side from the chuck electrode 53 does not increase, the adsorption force of the electrostatic chuck 10 does not decrease.

In addition, since the via 83 (83a) is arranged so as to be shifted in the radial direction (X-axis direction or Y-axis direction) so as not to overlap with the via 81 (81a, 81b) when viewed in the Z-axis direction, it is possible to prevent the amount of thrust toward the suction surface 51 side at the arrangement portion of the via 81 (81a, 81b) from increasing. In other words, by arranging the via 81a or 81b and the via 83a at the same position (in a straight line in the Z-axis direction), the thrust portions of the respective via arrangement portions are stacked, and the amount of thrust toward the suction surface 51 side at the via arrangement portion increases, preventing an increase in the height (dimension in the Z-axis direction) of the protruding portion 53a or 53b. As a result, it is possible to prevent a decrease in the thickness of the ceramic (insulating layer) on the suction surface 51 side from the chuck electrode 53 at the arrangement portion of the vias 81a and 81b, thereby improving the insulation of the electrostatic chuck 10 and preventing the occurrence of dielectric breakdown.

The vias 81 connected to the chuck electrode 53 other than the vias 81a and 81b, and the vias 83 connected to the connection pads 82 other than the vias 83a, may be arranged to overlap the convex portion 72 as viewed in the Z-axis direction, as described above. This forms the convex portion 72 directly above each arrangement portion of all the vias 81 (81a, 81b) connected to the chuck electrode 53 and all the vias 83 (83a) connected to the connection pads 82. Therefore, in each arrangement portion of all the vias 81 and 83, it is possible to prevent the thickness of the ceramic on the chucking surface 51 side from the chuck electrode 53 from decreasing. Therefore, the insulation property of the electrostatic chuck 10 is further improved, and the occurrence of dielectric breakdown can be more reliably prevented.

In addition, each of the vias 81 and 83 may be arranged to overlap one-to-one with the protrusion 72 when viewed in the Z-axis direction. In this way, the vias 81 and 83 are arranged apart from each other, so that it is possible to prevent the generation of temperature singularities (parts that become hotter than other parts) in the ceramic member 41 due to heat generation from the vias themselves. Furthermore, compared to when multiple vias 81 or vias 83 are arranged together so as to overlap one protrusion 72 (see FIG. 9), the temperature of the via arrangement part is lower, making it more difficult for insulation breakdown to occur in the via arrangement part.

The above embodiment is merely an example and does not limit the present disclosure in any way. Of course, various improvements and modifications are possible without departing from the spirit of the present disclosure. For example, in the above embodiment, the chuck electrode 53 is exemplified as the internal electrode located closest to the suction surface 51, but the internal electrode is not limited to the chuck electrode 53 and may be a high-frequency electrode.

In addition, in the above embodiment, vias 81 (81a, 81b) and vias 83 (83a) are exemplified as conductive members, but in addition to vias, metal terminals that embed metal rods (molded bodies) to effect internal connections can also be used.

In the above embodiment, the convex portion 72 and the via 81 or 83 are arranged to overlap one-to-one when viewed in the Z-axis direction, that is, only one of the vias 81 or 83 is arranged to overlap one convex portion 72. However, for example, as shown in FIG. 9, multiple vias 81 or 83 can be arranged to overlap one convex portion 72. Note that FIG. 9 illustrates a state in which two vias 81 (83) overlap, but three or more vias can also be arranged to overlap. In this way, when multiple vias are arranged to overlap one convex portion 72 when viewed in the Z-axis direction, it is preferable to form the size (e.g., diameter) of the convex portion 72 in the XY plane larger than in the case of a one-to-one arrangement as in the above embodiment.

10 electrostatic chuck 41 ceramic member 42 base member 51 chucking surface 53 chuck electrode 72 protrusion 81 via 81a via 81b via 82 connection pad 83 via 83a via 84 terminal pad W wafer

Claims (8)

A holding device for holding an object on the first surface of the plate-like member, the holding device comprising: a plate-like member having a first surface and a second surface provided on an opposite side to the first surface in a first direction; an internal electrode located closest to the first surface among electrodes provided inside the plate-like member; and a conductive member connected to the internal electrode extending in the first direction, the holding device comprising:
A plurality of protrusions are formed on the first surface,
the internal electrode is formed across the plurality of protrusions when viewed from the first direction,
the conductive member is disposed so as to overlap the protrusion when viewed from the first direction,
The conductive members are a plurality of vias connected to the internal electrodes.
A holding device characterized in that 2. The holding device according to claim 1 ,
A holding device, wherein the conductive members are all vias connected to the internal electrodes. The holding device according to claim 1 or 2 ,
The internal electrode includes a protruding portion that protrudes toward the first surface side,
The holding device, wherein the protrusion overlaps the plurality of vias when viewed from the first direction. 3. The holding device according to claim 2 ,
A holding device, characterized in that all of the vias are arranged to overlap one-to-one with the protrusions. A holding device for holding an object on the first surface of the plate-like member, the holding device comprising: a plate-like member having a first surface and a second surface provided on an opposite side to the first surface in a first direction; an internal electrode located closest to the first surface among electrodes provided inside the plate-like member; and a conductive member connected to the internal electrode extending in the first direction, the holding device comprising:
A plurality of protrusions are formed on the first surface,
the internal electrode is formed across the plurality of protrusions when viewed from the first direction,
the conductive member is disposed so as to overlap the protrusion when viewed from the first direction,
the conductive members are a plurality of vias connected to the internal electrodes,
a connection pad connected to the plurality of vias;
a plurality of second vias connected to the connection pads and disposed on the second surface side;
A holding device characterized in that the multiple vias and the multiple second vias are arranged offset in a second direction perpendicular to the first direction so as not to overlap when viewed from the first direction. 6. The holding device according to claim 5 ,
The holding device, characterized in that the plurality of second vias are arranged so as to overlap the protrusion when viewed from the first direction. 6. The holding device according to claim 5,
The conductive members are all vias connected to the internal electrodes.
A holding device characterized in that The holding device according to claim 5 or 7,
The internal electrode includes a protruding portion that protrudes toward the first surface side,
The protrusion overlaps with the plurality of vias when viewed from the first direction.
A holding device characterized in that

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