Holding member

Abstract

To provide a holding member which can improve heat drawing capacity from an object.SOLUTION: A plate-like member includes: a holding surface 11; and a lower surface 12 which is provided on an opposite side of the holding surface 11 in a Z-axis direction. An electrostatic chuck 1 for holding a semiconductor wafer W on the holding surface 11 has gas holes 16 formed on the holding surface 11 so as to discharge inactive gas, a gas tunnel 41 communicated with the gas holes 16, and a gas introduction port 42 for introducing inactive gas to the gas tunnel 41. Viewed from the Z-axis direction, the plurality of gas holes 16 are arranged side by side in a circumferential shape CI, and the gas introduction port 42 is arranged at a position overlapping a center CIa of the circumferential shape CI.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a holding member for holding an object. [Background technology]

[0002] As a document relating to a holding member, Patent Document 1 discloses a holding device for holding a wafer as an object. The holding device disclosed in Patent Document 1 has a gas ejection flow path that opens to the chucking surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-129632 Summary of the Invention [Problem to be solved by the invention]

[0004] In the holding device disclosed in Patent Document 1, inert gas is supplied from one vertical passage to multiple gas ejection passages. However, among the multiple gas ejection passages, the closer the gas ejection passage to the vertical passage, the greater the amount of inert gas supplied, while the farther the gas ejection passage from the vertical passage, the less inert gas supplied. This results in variations in the amount of inert gas ejected from the multiple gas ejection passages, which may prevent stable adsorption of the wafer to the adsorption surface of the ceramic member. This may result in a decrease in the ability to remove heat from the wafer (i.e., the ability to cool a high-temperature wafer from the ceramic member side).

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding member that can improve the ability to remove heat from an object. [Means for solving the problem]

[0006] One form of the present disclosure made to solve the above problems is a plate-shaped member having a first surface and a second surface provided on the opposite side of the first surface in a first direction, wherein a holding member that holds an object on the first surface of the plate-shaped member has an opening formed on the first surface for discharging gas, a communication passage that communicates with the opening, and a gas inlet that introduces the gas into the communication passage, wherein when viewed from the first direction, the multiple openings are arranged in a circumferential shape, and the gas inlet is arranged at a position that overlaps with the center of the circumferential shape.

[0007] According to this embodiment, the lengths of the communication paths from the gas inlet to each opening can be made equal. Therefore, the gas discharge force from each opening can be made equal. Therefore, the object is stably held on the first surface of the plate-shaped member, and the gas filling pressure on the first surface can be increased, improving the heat-drawing ability from the object (i.e., the ability to cool a high-temperature object from the plate-shaped member side). The plate-shaped member (holding member) can be, for example, composed of a ceramic member and a metal member, or composed of a ceramic member and a ceramic member.

[0008] In the above aspect, it is preferable that the plate-shaped member has a communication passage portion formed so that the communication passage extends in a planar direction of the first surface, and the gas inlet is provided at the position of the communication passage portion.

[0009] According to this embodiment, the gas supplied from the second surface side of the plate-shaped member can be supplied to the gas inlet formed in the communication passage while circulating inside the plate-shaped member. Therefore, the gas can be supplied to the gas inlet while avoiding other components (such as electrodes) provided inside the plate-shaped member. Therefore, regardless of the internal structure of the plate-shaped member, the inert gas can be reliably introduced from the gas inlet to the opening through the communication passage. Note that the communication passage is formed, for example, inside the ceramic member constituting the plate-shaped member or inside the metal member constituting the plate-shaped member.

[0010] Another aspect of the present disclosure made to solve the above problems is a plate-like member having a first surface and a second surface provided on the opposite side of the first surface in a first direction, wherein a holding member for holding an object on the first surface of the plate-like member has an opening formed on the first surface for discharging gas, a communication passage communicating with the opening, and a gas inlet for introducing the gas into the communication passage, wherein, when viewed from the first direction, a plurality of the openings are arranged in a circumferential shape, the gas inlet is arranged at a position overlapping with the circumferential shape, and the proportion of the openings per unit area is preferably greater at a position where the opening farthest from the gas inlet is formed than at a position where the opening closest to the gas inlet is formed.

[0011] According to this aspect, the gas discharge force can be ensured even at the position where the opening farthest from the gas inlet is formed. Therefore, the difference in gas discharge force between the position where the opening closest to the gas inlet is formed and the position where the opening farthest from the gas inlet is formed can be suppressed. Therefore, the object is stably held on the first surface of the plate-shaped member, and the gas filling pressure on the first surface can be increased, improving the heat transfer ability from the object. Note that the plate-shaped member (holding member) is, for example, composed of a ceramic member and a metal member, or composed of a ceramic member and a ceramic member.

[0012] In the above aspect, it is preferable that, when viewed from the first direction, the ratio increases from the position where the opening closest to the gas inlet is formed, along the circumferential shape, toward the position where the opening farthest from the gas inlet is formed.

[0013] According to this aspect, the gas discharge force from each opening can be ensured regardless of the distance from the gas inlet. Therefore, the difference in gas discharge force from each opening can be reduced. Therefore, the object is more effectively and stably held on the first surface of the plate-shaped member, and the gas filling pressure on the first surface can be increased, improving the heat transfer ability from the object.

[0014] In the above aspect, it is preferable that the ratio is adjusted by the area of ​​the opening.

[0015] According to this aspect, by adjusting the area of ​​the openings and thereby adjusting the ejection force of the inert gas from the openings, it is possible to suppress the difference in the ejection force of the gas from the plurality of openings.

[0016] In the above aspect, it is preferable that the ratio is adjusted by adjusting the interval between adjacent openings.

[0017] According to this aspect, by adjusting the spacing between adjacent openings and adjusting the gas ejection force from the openings, it is possible to suppress differences in gas ejection force among the plurality of openings.

[0018] In the above aspect, it is preferable that the opening is made up of a plurality of holes, and the ratio is adjusted by adjusting the density of the holes.

[0019] According to this aspect, by adjusting the density of the holes and thereby adjusting the gas ejection force from the openings, it is possible to suppress the difference in gas ejection force among the plurality of openings. [Effects of the Invention]

[0020] The holding member of the present disclosure can improve the ability to remove heat from an object. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck according to first and second embodiments. [Figure 2] 2 is a schematic configuration diagram of an XZ side surface (partial cross section) of the electrostatic chuck of the first and second embodiments. FIG. [Figure 3] FIG. 2 is a schematic configuration diagram of the electrostatic chuck of the first and second embodiments in the XY plane. [Figure 4] FIG. 2 is a diagram illustrating a gas hole on the holding surface of the ceramic member, and a gas tunnel and a gas inlet port inside the ceramic member in the first embodiment. [Figure 5] FIG. 1 is a cross-sectional view of a ceramic member according to a first embodiment. [Figure 6] FIG. 10 is a diagram showing a schematic diagram of gas holes on a holding surface of a ceramic member, and gas tunnels and gas inlets inside the ceramic member in a first example of the second embodiment. [Figure 7] FIG. 10 is a diagram schematically showing gas holes on the holding surface of the ceramic member, and gas tunnels and gas inlets inside the ceramic member in a second example of the second embodiment. [Figure 8] FIG. 10 is a diagram showing a schematic diagram of gas holes on the holding surface of the ceramic member, and gas tunnels and gas inlets inside the ceramic member in a third example of the second embodiment. [Figure 9] FIG. 1 is a diagram showing a schematic diagram of gas holes on a holding surface of a ceramic member, and gas tunnels and gas inlets inside the ceramic member in the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the holding member of the present disclosure will be described. In the following embodiment, a case where the holding member of the present disclosure is applied to an electrostatic chuck 1 that holds a semiconductor wafer W will be described.

[0023] [First embodiment] First, the first embodiment will be described.

[0024] <Overall structure of electrostatic chuck> The electrostatic chuck 1 of this embodiment is a plate-shaped member that attracts and holds a semiconductor wafer W (object) by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. As shown in FIG. 1 , the electrostatic chuck 1 has a ceramic member 10, a base member 20, and a bonding layer 30 that bonds the ceramic member 10 and the base member 20 together. The electrostatic chuck 1 is an example of the "holding member" or "plate-shaped member" of the present disclosure.

[0025] In the following description, for convenience of explanation, the X, Y, and Z axes are defined as shown in Fig. 1. Here, the Z axis is an axis in the axial direction of the electrostatic chuck 1 (the vertical direction in Fig. 1), and the X and Y axes are axes in the radial direction of the electrostatic chuck 1.

[0026] As shown in Fig. 1, the ceramic member 10 is a disk-shaped member made of 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, Al2O3) or aluminum nitride (AlN). Note that the term "main component" as used here refers to the component with the highest content (for example, a component with a volume content of 90 vol% or more).

[0027] The ceramic member 10 has a diameter of, for example, about 150 to 300 mm. The ceramic member 10 has a thickness of, for example, about 2 to 6 mm. The ceramic member 10 preferably has a thermal conductivity in the range of 10 to 50 W / mK (more preferably, 18 to 30 W / mK).

[0028] 1 and 2, the ceramic member 10 includes a holding surface 11 that holds a semiconductor wafer W, and a lower surface 12 that is provided on the opposite side of the holding surface 11 in the thickness direction (Z-axis direction, up-down direction) of the ceramic member 10. The Z-axis direction is an example of a "first direction" in the present disclosure. The holding surface 11 is also an example of a "first surface" in the present disclosure.

[0029] The holding surface 11 of the ceramic member 10 has an uneven shape. Specifically, as shown in FIGS. 2 and 3, the holding surface 11 has an annular convex portion 13 formed near its outer edge, and a plurality of independent columnar convex portions 14 formed inside the annular convex portion 13. In this way, the holding surface 11 has the annular convex portion 13 arranged so as to surround all of the plurality of convex portions 14. The annular convex portion 13 is also called a seal band. As shown in FIG. 2, the cross section (XZ cross section) of the annular convex portion 13 has a substantially rectangular shape. The height (dimension in the Z-axis direction) of the annular convex portion 13 is, for example, about 10 μm to 20 μm. The width (dimension in the X-axis direction) of the annular convex portion 13 is, for example, about 0.5 mm to 5.0 mm.

[0030] As shown in FIG. 3, each of the protrusions 14 has a substantially circular shape when viewed in the Z-axis direction (plan view), and is arranged at substantially equal intervals. Furthermore, the cross-sectional shape (XZ cross-section) of each of the protrusions 14 is substantially rectangular, as shown in FIG. 2. The height of each of the protrusions 14 is substantially the same as the height of the annular protrusion 13, and is, for example, about 10 to 20 μm. Furthermore, the width of each of the protrusions 14 (maximum diameter of the protrusion 14 when viewed in the Z-axis direction) is, for example, about 0.5 to 1.5 mm. The portions of the holding surface 11 of the ceramic member 10 inside the annular protrusion 13 where no protrusions 14 are formed are recesses 15.

[0031] The semiconductor wafer W is supported by the annular convex portion 13 and the multiple convex portions 14 on the holding surface 11 of the ceramic member 10 and is held by the electrostatic chuck 1. When the semiconductor wafer W is held by the electrostatic chuck 1, a space S exists between the surface (lower surface) of the semiconductor wafer W and the holding surface 11 of the ceramic member 10 (more specifically, the recessed portion 15 of the holding surface 11) (see FIG. 2). An inert gas (e.g., helium gas) is supplied to this space S through a gas hole 16 shown in FIG. 3. The gas hole 16 is an opening formed in the holding surface 11.

[0032] 3, a plurality of gas holes 16 (eight in the example shown in FIG. 3) are provided. Each gas hole 16 may be composed of a single hole as shown in FIG. 3, or may be composed of a gas hole group consisting of a plurality of holes (for example, a plurality of small holes 51 shown in FIG. 8, which will be described later).

[0033] The base member 20 is formed in a cylindrical shape as shown in Fig. 1. This base member 20 is preferably a metal member made of metal (for example, aluminum or an aluminum alloy), but may be made of a material other than metal.

[0034] 1 to 3, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the thickness direction of the base member 20 (i.e., the Z-axis direction). The upper surface 21 of the base member 20 is thermally connected to the lower surface 12 of the ceramic member 10 via a bonding layer 30. The lower surface 22 is an example of the "second surface" of the present disclosure.

[0035] The diameter of the base member 20 is, for example, about 180 mm to 350 mm. The thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm. The thermal conductivity of the base member 20 (assumed to be aluminum) is greater than that of the ceramic member 10, and is desirably within the range of 180 to 250 W / mK (preferably, about 230 W / mK).

[0036] The bonding layer 30 is disposed between the lower surface 12 of the ceramic member 10 and the base member 20, and bonds the ceramic member 10 and the base member 20 together. The lower surface 12 of the ceramic member 10 and the base member 20 are thermally connected via the bonding layer 30. The bonding layer 30 is made of an adhesive material such as a silicone-based resin, an acrylic-based resin, or an epoxy-based resin. The thickness (dimension in the Z-axis direction) of the bonding layer 30 is, for example, about 0.1 to 1.0 mm. The thermal conductivity of the bonding layer 30 is, for example, 1.0 W / mK. The thermal conductivity of the bonding layer 30 (assumed to be a silicone-based resin) is preferably within a range of 0.1 to 2.0 W / mK (preferably 0.5 to 1.5 W / mK).

[0037] <Means for improving heat dissipation from semiconductor wafers> 9 , in the prior art, a plurality of gas holes 16 are arranged in a circumferential shape at equal intervals in the circumferential direction, and the areas (opening area, hole diameter) of the plurality of gas holes 16 are all the same. A gas inlet 42 for introducing an inert gas into a gas tunnel 41 communicating with the gas holes 16 is provided below an arbitrary gas hole 16. Therefore, the amount of inert gas supplied to the gas holes 16 closer to the gas inlet 42 increases, which tends to cause a decrease in the chucking force of the electrostatic chuck 1 (i.e., a state in which it becomes difficult for the semiconductor wafer W to be attracted to the holding surface 11 of the ceramic member 10 (dechucking state)).

[0038] This may result in a decrease in adhesion between the semiconductor wafer W and the holding surface 11 of the ceramic member 10, making it difficult to increase the filling pressure of the inert gas in the space S that exists between the semiconductor wafer W and the holding surface 11 of the ceramic member 10. Therefore, the heat of the semiconductor wafer W may not be sufficiently removed from the holding surface 11 side of the ceramic member 10 via the inert gas that fills the space S, and the heat removal capacity of the semiconductor wafer W (i.e., the capacity to cool the high-temperature semiconductor wafer W from the ceramic member 10 side) may decrease.

[0039] Therefore, in this embodiment, the chucking force of the electrostatic chuck 1 is improved by devising the gas holes 16, the gas tunnel 41, and the gas inlet 42. This increases the filling pressure of the inert gas in the space S, thereby improving the heat transfer capability from the semiconductor wafer W. The gas tunnel 41 is an example of a "communication passage" in the present disclosure.

[0040] Specifically, as shown in Fig. 4, when the ceramic member 10 of the electrostatic chuck 1 is viewed from the holding surface 11 side in the Z-axis direction (hereinafter simply referred to as "when the electrostatic chuck 1 is viewed from above"), a plurality of gas holes 16 are arranged side by side in a circumferential shape, and the gas inlet 42 is arranged at a position overlapping with the center of the circumferential shape. Note that, as shown in Fig. 4, the plurality of gas holes 16 are arranged at equal intervals in the circumferential direction, and the area (opening area, hole diameter) of each gas hole 16 is the same.

[0041] The diameter of the gas holes 16 is 0.1 mm to 2.0 mm, and the diameter of the gas inlet 42 is 1.0 mm to 5.0 mm. As an example, the diameter of the gas holes 16 is 0.5 mm, and the diameter of the gas inlet 42 is 3.0 mm. The number of gas holes 16 is eight in the examples shown in Figures 3 and 4, but is not particularly limited as long as it is plural, and may be, for example, 12 or 24.

[0042] 4, when the electrostatic chuck 1 is viewed from above, the center 16a of each circular gas hole 16 is disposed on an imaginary circumferential shape CI (the shape indicated by the dashed line in FIG. 4). The center 42a of the gas inlet 42 having a circular outer periphery is disposed so as to overlap with the center CIa of the imaginary circumferential shape CI.

[0043] 4 is merely an example, and the centers 16a of the gas holes 16 do not have to be positioned on the imaginary circumferential shape CI as shown in Fig. 4, as long as any part of each gas hole 16 is positioned on the imaginary circumferential shape CI. Furthermore, the centers 42a of the gas inlets 42 do not have to be positioned so as to overlap with the center CIa of the imaginary circumferential shape CI as shown in Fig. 4, as long as any part of the gas inlets 42 is positioned so as to overlap with the center CIa of the imaginary circumferential shape CI.

[0044] In this embodiment, a plurality of gas holes 16 and gas inlets 42 are arranged in this manner, and a plurality of gas tunnels 41 are formed to connect each of the gas holes 16 and gas inlets 42.

[0045] This makes it possible to equalize the lengths of the gas tunnels 41 from the gas inlet 42 to each gas hole 16. This makes it possible to equalize the discharge force of the inert gas from each gas hole 16. Therefore, the semiconductor wafer W is stably held on the holding surface 11 of the ceramic member 10, and the filling pressure of the inert gas on the holding surface 11 can be increased, thereby improving the heat transfer capability from the semiconductor wafer W.

[0046] 4 and 5, the ceramic member 10 has a gas tunnel portion 43 formed therein such that a plurality of gas tunnels 41 extend in the planar direction of the holding surface 11 (the left-right direction in FIG. 5). The gas inlet 42 is provided at the position of the gas tunnel portion 43, not at the position of the lower surface 12 of the ceramic member 10. The gas tunnel portion 43 is an example of a "communicating passage portion" in the present disclosure. As shown in FIG. 5, an inert gas is supplied to the gas inlet 42 from a gas inlet path 44 that connects the gas inlet 42 and the lower surface 12 of the ceramic member 10.

[0047] As a result, the inert gas supplied from the lower surface 12 side of the ceramic member 10 can be routed inside the ceramic member 10 through the gas inlet 44 formed, for example, as shown by the dashed line in FIG. 5, and supplied to the gas inlet 42 formed in the gas tunnel portion 43. Therefore, the inert gas can be supplied to the gas inlet 42 while avoiding other components (electrodes, etc.) provided inside the ceramic member 10. Therefore, regardless of the internal structure of the ceramic member 10, the inert gas can be reliably introduced from the gas inlet 42 through the gas tunnel 41 into the gas hole 16.

[0048] Second Embodiment Next, the second embodiment will be described, but differences from the first embodiment will be described, and a description of commonalities with the first embodiment will be omitted.

[0049] (First Example) First, a first example of the second embodiment will be described. In this example, as shown in Fig. 6, when the electrostatic chuck 1 is viewed from above, a plurality of gas holes 16 are arranged in a circumferential direction. In the example shown in Fig. 6, the plurality of gas holes 16 are arranged such that the centers 16a of the respective gas holes 16 are arranged in a circumferential direction (i.e., arranged on a virtual circumferential shape CI) and are spaced apart at equal intervals in the circumferential direction.

[0050] 6, eight gas holes 16 are arranged as the plurality of gas holes 16: a first gas hole 16-1, a second gas hole 16-2, a third gas hole 16-3, a fourth gas hole 16-4, a fifth gas hole 16-5, a sixth gas hole 16-6, a seventh gas hole 16-7, and an eighth gas hole 16-8. However, the areas of the individual gas holes 16 are different. For example, the diameter of the first gas hole 16-1 is 0.2 mm, the diameter of the second gas hole 16-2 is 0.5 mm, the diameter of the third gas hole 16-3 is 0.7 mm, the diameter of the fourth gas hole 16-4 is 0.8 mm, the diameter of the fifth gas hole 16-5 is 0.9 mm, the diameter of the sixth gas hole 16-6 is 0.8 mm, the diameter of the seventh gas hole 16-7 is 0.7 mm, and the diameter of the eighth gas hole 16-8 is 0.5 mm.

[0051] 6, the gas inlet 42 is disposed at a position overlapping with the circumferential shape (i.e., the imaginary circumferential shape CI) when the electrostatic chuck 1 is viewed from above. In the example shown in FIG. 6, the gas inlet 42 is disposed at a position overlapping with the first gas hole 16-1.

[0052] In this embodiment, the area of ​​the fifth gas hole 16-5, which is farthest from the gas inlet 42, is larger than the area of ​​the first gas hole 16-1, which is closest to the gas inlet 42. For example, the area of ​​the fifth gas hole 16-5 is two or three times larger than the area of ​​the first gas hole 16-1.

[0053] The area of ​​each gas hole 16 increases from the first gas hole 16-1 to the fifth gas hole 16-5 along the circumferential shape. That is, the area of ​​each gas hole 16 increases from the first gas hole 16-1 to the second gas hole 16-2, the third gas hole 16-3, the fourth gas hole 16-4, and the fifth gas hole 16-5. The area of ​​each gas hole 16 also increases from the first gas hole 16-1 to the eighth gas hole 16-8, the seventh gas hole 16-7, the sixth gas hole 16-6, and the fifth gas hole 16-5. Note that as the area of ​​the gas hole 16 increases, the volume of the hole connected to the gas hole 16 (i.e., the hole at the connection between the gas hole 16 and the gas tunnel 41) also increases.

[0054] Thus, in this embodiment, when the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area (i.e., the proportion of the gas holes 16 per unit area obtained by dividing the holding surface 11, which has a circular outer periphery, into multiple equal parts in the circumferential direction) is greater at the position where the fifth gas hole 16-5, which is farthest from the gas inlet 42, is formed than at the position where the first gas hole 16-1, which is closest to the gas inlet 42, is formed.

[0055] That is, as shown in Figure 6, first, for example, the holding surface 11 is divided into eight equal unit areas in the circumferential direction, and the following unit areas are assumed: a first unit area 11-1, a second unit area 11-2, a third unit area 11-3, a fourth unit area 11-4, a fifth unit area 11-5, a sixth unit area 11-6, a seventh unit area 11-7, and an eighth unit area 11-8.

[0056] At this time, since the area of ​​the fifth gas hole 16-5 is larger than the area of ​​the first gas hole 16-1, the proportion of the gas hole 16 (i.e., the first gas hole 16-1) in the first unit area 11-1 at the position where the first gas hole 16-1 closest to the gas inlet 42 is formed is larger than the proportion of the gas hole 16 (i.e., the fifth gas hole 16-5) in the fifth unit area 11-5 at the position where the fifth gas hole 16-5 farthest from the gas inlet 42 is formed.

[0057] When the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area increases from the position where the first gas hole 16-1, closest to the gas inlet 42, is formed, along the circumferential shape toward the position where the fifth gas hole 16-5, farthest from the gas inlet 42, is formed.

[0058] That is, as shown in FIG. 6, the area of ​​the gas holes 16 increases from the first gas hole 16-1 to the second gas hole 16-2, the third gas hole 16-3, the fourth gas hole 16-4, and the fifth gas hole 16-5, and therefore the proportion of the gas holes 16 per unit area increases from the first unit area 11-1 to the second unit area 11-2, the third unit area 11-3, the fourth unit area 11-4, and the fifth unit area 11-5. Furthermore, since the area of ​​the gas holes 16 increases from the first gas hole 16-1 to the eighth gas hole 16-8, the seventh gas hole 16-7, the sixth gas hole 16-6, and the fifth gas hole 16-5, the proportion of the gas holes 16 per unit area increases from the first unit area 11-1 to the eighth unit area 11-8, the seventh unit area 11-7, the sixth unit area 11-6, and the fifth unit area 11-5.

[0059] In this way, in this embodiment, the proportion of the gas holes 16 per unit area is adjusted by the area of ​​the gas holes 16 .

[0060] (Second Example) Next, a second example of the second embodiment will be described. In this example, as shown in Fig. 7, when the electrostatic chuck 1 is viewed from above, the interval δ between adjacent gas holes 16 in the circumferential direction is narrower at the position of the fifth gas hole 16-5, which is farthest from the gas inlet 42, than at the position of the first gas hole 16-1, which is closest to the gas inlet 42. In the example shown in Fig. 7, the plurality of gas holes 16 are arranged such that the centers 16a of the respective gas holes 16 are aligned in a circumferential shape (i.e., aligned on a virtual circumferential shape CI).

[0061] The interval δ between adjacent gas holes 16 in the circumferential direction narrows from the first gas hole 16-1 along the circumferential shape toward the fifth gas hole 16-5 (δ1 > δ2 > δ3 > δ4). For example, the interval δ1 is 90 mm, the interval δ2 is 80 mm, the interval δ3 is 75 mm, and the interval δ4 is 55 mm.

[0062] In this way, also in this embodiment, when the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area is greater at the position where the fifth gas hole 16-5, which is farthest from the gas inlet 42, is formed than at the position where the first gas hole 16-1, which is closest to the gas inlet 42, is formed.

[0063] That is, as shown in FIG. 7, first, for example, the holding surface 11 is divided into four equal unit areas in the circumferential direction, and a first unit area 11-1, a second unit area 11-2, a third unit area 11-3, and a fourth unit area 11-4 are assumed.

[0064] In this case, since the intervals δ3 and δ4 are narrower than the interval δ1, the proportion of the gas holes 16 (i.e., the fourth gas hole 16-4, the fifth gas hole 16-5, and the sixth gas hole 16-6) in the third unit area 11-3 at the position where the fifth gas hole 16-5, farthest from the gas inlet 42, is formed is greater than the proportion of the gas holes 16 (i.e., the first gas hole 16-1) in the first unit area 11-1 at the position where the first gas hole 16-1, closest to the gas inlet 42, is formed.

[0065] The proportion of the gas holes 16 per unit area increases from the position where the first gas holes 16-1 are formed along the circumferential shape toward the position where the fifth gas holes 16-5 are formed.

[0066] 7, the interval δ narrows from the first gas hole 16-1 to the fifth gas hole 16-5 along the circumferential shape, and the number of gas holes 16 provided is one in the first unit area 11-1, two in the second unit area 11-2, and three in the third unit area 11-3. As a result, the proportion of gas holes 16 per unit area increases from the first unit area 11-1 to the second unit area 11-2 and the third unit area 11-3.

[0067] The spacing δ narrows from the first gas hole 16-1 to the fifth gas hole 16-5 along the circumferential shape, and the number of gas holes 16 provided is one in the first unit area 11-1, two in the fourth unit area 11-4, and three in the third unit area 11-3. As a result, the proportion of gas holes 16 per unit area increases from the first unit area 11-1 to the fourth unit area 11-4 and to the third unit area 11-3.

[0068] In this way, in this embodiment, the ratio of the gas holes 16 to the unit area is adjusted by the interval δ between adjacent gas holes 16. Note that the ratio of the gas holes 16 to the unit area may be adjusted by both the interval δ between adjacent gas holes 16 and the area of ​​the gas holes 16 as in the first embodiment.

[0069] (Third Example) Next, a third example of the second embodiment will be described. In this example, as shown in FIG. 8 , when the electrostatic chuck 1 is viewed from above, the gas holes 16 are composed of a plurality of small holes 51. The small holes 51 are an example of the “holes” in the present disclosure. The number of small holes 51 constituting one gas hole 16 is greater in the fifth gas hole 16-5, which is farthest from the gas inlet 42, than in the first gas hole 16-1, which is closest to the gas inlet 42. That is, the density of the plurality of small holes 51 constituting one gas hole 16 is higher in the fifth gas hole 16-5 than in the first gas hole 16-1. The diameter of the small holes 51 is 0.1 mm to 2.0 mm, and the number of small holes 51 constituting one gas hole 16 is 1 to 50. As an example, the diameter of the small holes 51 is, for example, 0.3 mm, and the number of small holes 51 constituting one gas hole 16 is, for example, 3 to 7.

[0070] The number of small holes 51 constituting one gas hole 16 increases along the circumference from the first gas hole 16-1, which is closest to the gas inlet 42, to the fifth gas hole 16-5, which is farthest from the gas inlet 42. That is, the density of the multiple small holes 51 constituting one gas hole 16 increases along the circumference from the first gas hole 16-1 to the fifth gas hole 16-5.

[0071] In this way, also in this embodiment, when the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area is greater at the position where the fifth gas hole 16-5, which is farthest from the gas inlet 42, is formed than at the position where the first gas hole 16-1, which is closest to the gas inlet 42, is formed.

[0072] That is, as shown in FIG. 8, the density of the multiple small holes 51 that constitute one gas hole 16 is higher in the fifth gas hole 16-5 than in the first gas hole 16-1, and therefore the proportion of the fifth gas holes 16-5 (more specifically, the small holes 51 that constitute the fifth gas hole 16-5) in the fifth unit area 11-5 at the position where the fifth gas hole 16-5 is formed is greater than the proportion of the first gas holes 16-1 (more specifically, the small holes 51 that constitute the first gas hole 16-1) in the first unit area 11-1 at the position where the first gas hole 16-1 is formed.

[0073] The proportion of gas holes 16 (more specifically, the small holes 51 that constitute the gas holes 16) per unit area increases from the position where the first gas hole 16-1, which is closest to the gas inlet 42, is formed, along the circumferential shape toward the position where the fifth gas hole 16-5, which is farthest from the gas inlet 42, is formed.

[0074] 8, the density of the multiple small holes 51 constituting one gas hole 16 increases from the first gas hole 16-1 along the circumferential shape toward the fifth gas hole 16-5, and the number of small holes 51 provided is three in the first unit area 11-1, four in the second unit area 11-2, five in the third unit area 11-3, six in the fourth unit area 11-4, and seven in the fifth unit area 11-5. As a result, the proportion of gas holes 16 (more specifically, the small holes 51 constituting the gas hole 16) per unit area increases from the first unit area 11-1 to the second unit area 11-2, the third unit area 11-3, the fourth unit area 11-4, and the fifth unit area 11-5.

[0075] The density of the multiple small holes 51 constituting one gas hole 16 increases from the first gas hole 16-1 along the circumferential shape toward the fifth gas hole 16-5, and the number of small holes 51 provided is three in the first unit area 11-1, four in the eighth unit area 11-8, five in the seventh unit area 11-7, six in the sixth unit area 11-6, and seven in the fifth unit area 11-5. As a result, the proportion of gas holes 16 per unit area increases from the first unit area 11-1 to the eighth unit area 11-8, the seventh unit area 11-7, the sixth unit area 11-6, and the fifth unit area 11-5.

[0076] In this manner, in this embodiment, the proportion of the gas holes 16 per unit area is adjusted by the density of the small holes 51.

[0077] (Effects of the second embodiment) As described above, in the second embodiment, when the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area is greater at the position where the fifth gas hole 16-5, which is farthest from the gas inlet port 42, is formed than at the position where the first gas hole 16-1, which is closest to the gas inlet port 42, is formed.

[0078] This ensures the discharge force of the inert gas even at the position where the fifth gas hole 16-5 is formed, which is farthest from the gas inlet 42. Therefore, it is possible to suppress the difference in the discharge force of the inert gas between the position where the first gas hole 16-1 closest to the gas inlet 42 is formed and the position where the fifth gas hole 16-5 farthest from the gas inlet 42 is formed. Therefore, the semiconductor wafer W is stably held on the holding surface 11 of the ceramic member 10, and the filling pressure of the inert gas on the holding surface 11 can be increased, thereby improving the heat transfer capability from the semiconductor wafer W.

[0079] When the electrostatic chuck 1 is viewed from above, the proportion of the gas holes 16 per unit area increases from the position where the first gas hole 16-1, closest to the gas inlet 42, is formed, along the circumferential shape, toward the position where the fifth gas hole 16-5, farthest from the gas inlet 42, is formed.

[0080] This ensures the discharge force of the inert gas from each gas hole 16 regardless of the distance from the gas inlet 42. This reduces the difference in the discharge force of the inert gas from each gas hole 16. Therefore, the semiconductor wafer W is more effectively and stably held on the holding surface 11 of the ceramic member 10, and the filling pressure of the inert gas on the holding surface 11 can be increased, thereby improving the heat transfer capability from the semiconductor wafer W.

[0081] In the first embodiment, the proportion of the gas holes 16 per unit area is adjusted by adjusting the area of ​​the gas holes 16.

[0082] In this way, by adjusting the area of ​​the gas holes 16 and adjusting the discharge force of the inert gas from the gas holes 16, the difference in the discharge force of the inert gas from the plurality of gas holes 16 can be suppressed.

[0083] In the second embodiment, the proportion of the gas holes 16 per unit area is adjusted by the interval δ between adjacent gas holes 16.

[0084] In this way, by adjusting the spacing δ between adjacent gas holes 16 and adjusting the discharge force of the inert gas from the gas holes 16, the difference in the discharge force of the inert gas from the plurality of gas holes 16 can be suppressed.

[0085] In the third embodiment, the gas holes 16 are made up of a plurality of small holes 51, and the proportion of the gas holes 16 per unit area is adjusted by the density of the small holes 51.

[0086] In this way, by adjusting the density of the small holes 51 and adjusting the discharge force of the inert gas from the gas holes 16, the difference in the discharge force of the inert gas from the plurality of gas holes 16 can be suppressed.

[0087] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications are possible within the scope of the gist of the present disclosure.

[0088] For example, although the gas holes 16 are arranged in a single circumferential shape in FIG. 3 and other figures, the present invention is not limited to this and the gas holes 16 may be arranged in a double or triple circumferential shape.

[0089] Furthermore, the electrostatic chuck 1 is not limited to being made up of the ceramic member 10, the base member 20, and the bonding layer 30, but may be made up of a ceramic member, a ceramic member, and a bonding layer.

[0090] Moreover, the gas tunnel portion 43 may be formed inside the base member 20 . [Explanation of symbols]

[0091] 1. Electrostatic chuck 10 Ceramic materials 11 Holding surface 11-1 First unit area 11-2 Second Unit Area 11-3 Third Unit Area 11-4 Fourth Unit Area 11-5 5th Unit Area 11-6 6th Unit Area 11-7 7th Unit Area 11-8 8th Unit Area 12 Bottom side 13 Annular convex part 14 Convex part 15 recess 16 Gas vent 16a center 16-1 First gas hole 16-2 Second gas hole 16-3 Third gas hole 16-4 No. 4 gas hole 16-5 No. 5 gas hole 16-6 No. 6 gas hole 16-7 No. 7 gas hole 16-8 No. 8 gas hole 20 Base member 21 Top side 22 Bottom side 30 Bonding layer 41 Gas Tunnel 42 Gas inlet 42a center 43 Gas Tunnel Section 44 Gas inlet 51 small hole W Semiconductor wafer S space CI Virtual Circumference CIa-centered δ,δ1,δ2,δ3,δ4 intervals

Claims

1. A ceramic member formed of ceramic having a first surface and a second surface provided on the opposite side of the first surface in a first direction, the ceramic member holding an object on the first surface, and a base member joined to the ceramic member, The ceramic member is an opening formed on the first surface for discharging a gas; a communication passage communicating with the opening; a gas inlet for introducing the gas into the communication passage; and When viewed from the first direction, A plurality of the openings are arranged side by side in a circumferential shape, the gas inlet is disposed at a position overlapping with the circumferential shape, the ratio of the openings per unit area is larger at a position where the openings are formed farthest from the gas inlet than at a position where the openings are formed closest to the gas inlet; A holding member characterized by:

2. The holding member of claim 1, When viewed from the first direction, the ratio increases from a position where the opening is closest to the gas inlet to a position where the opening is farthest from the gas inlet along the circumferential shape; A holding member characterized by:

3. The holding member according to claim 1 or 2, The ratio is adjusted depending on the area of ​​the opening. A holding member characterized by:

4. 4. The holding member according to claim 1, the ratio is adjusted by adjusting the interval between adjacent openings; A holding member characterized by:

5. The holding member according to claim 1 or 2, The opening is made up of a plurality of holes, The ratio is adjusted according to the density of the holes; A holding member characterized by:

6. 6. The holding member according to claim 1, When viewed from the first direction, no openings other than the plurality of openings are arranged inside the circumferential shape; A holding member characterized by:

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