Keeping device

Abstract

To provide a keeping device that can increase the flow rate of gas to be supplied to a placement surface without affecting the temperature distribution of the placement surface.SOLUTION: An electrostatic chuck 1 includes a plate-shaped member 10 including a placement surface 11 where a semiconductor wafer W to be kept is placed, and a gas flow channel 40 formed in the plate-shaped member 10 so as to supply inert gas to the placement surface 11. The gas flow channel 40 includes a lateral gas flow cannel 44 extending in a planar direction in the plate-shaped member 10, and a plurality of gas discharge flow channels 42 that extend in the thickness direction of the plate-shaped member 10 and have one end communicating with the lateral gas flow channel 44 and the other end open to the placement surface 11. In a particular cross section that is perpendicular to a longitudinal direction of the lateral gas flow channel 44 and that includes one gas discharge flow channel 42, a side 44a on the placement surface 11 side that defines the lateral gas flow channel 44 is inclined with respect to a vertical line L perpendicular to a direction where the discharge flow channel 42 extends.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Electrostatic chucks are known as holding devices for holding an object. In order to improve heat exchange with the held object, electrostatic chucks supply and fill an inert gas into a minute space between a mounting surface and the object. In this type of electrostatic chuck, as described in Patent Document 1, for example, a gas flow path is formed inside a ceramic insulator (plate-shaped member). This gas flow path includes a horizontal hole extending in the planar direction of the ceramic insulator (plate-shaped member) and a vertical hole extending in the thickness direction of the ceramic insulator (plate-shaped member) and communicating with the horizontal hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4768333 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, electrostatic chucks have increasingly been applied with high voltages (high power use), which has resulted in a tendency for the temperature of the object being held to become higher than before.The higher the temperature of the object, the lower the efficiency of the process performed on the object, so there is a demand for heat removal capabilities (improved heat removal capabilities) that can reduce the temperature of the object in a short period of time.

[0005] Therefore, in order to improve heat removal, it is desirable to increase the flow rate of gas supplied to the mounting surface. Increasing the diameter of the vertical hole (cross-sectional area of ​​the flow path) can increase the flow rate of gas supplied to the mounting surface, but increasing the diameter of the vertical hole expands the area of ​​temperature singularities formed around the opening of the vertical hole on the mounting surface. This results in a problem of reduced uniformity of the temperature distribution on the mounting surface. Under these circumstances, it is desirable to increase the flow rate of gas without changing the diameter of the vertical hole (cross-sectional area of ​​the flow path).

[0006] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can increase the flow rate of gas supplied to the mounting surface without affecting the temperature distribution on the mounting surface. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present disclosure is to a plate-like member having a placement surface on which an object to be held is placed; a gas flow path formed in the plate-shaped member for supplying an inert gas to the mounting surface; In a holding device having The gas flow path is a horizontal hole extending in a planar direction within the plate-like member; a plurality of vertical holes extending in a thickness direction of the plate-like member, one end of which communicates with the horizontal hole and the other end of which opens to the placement surface; In a specific cross section perpendicular to the longitudinal direction of the horizontal hole and including one of the vertical holes, The side of the placement surface that defines the horizontal hole is inclined with respect to a perpendicular line perpendicular to the direction in which the vertical hole extends.

[0008] In this holding device, a gas flow path consisting of a horizontal hole and a vertical hole is formed in a plate-shaped member. In a specific cross section perpendicular to the longitudinal direction of the horizontal hole and including one vertical hole, the side of the mounting surface that defines the horizontal hole is inclined with respect to a perpendicular line perpendicular to the direction in which the vertical hole extends. This allows the entrance (area) of the vertical hole to be enlarged at the point where the vertical hole connects to the horizontal hole (the portion corresponding to the gas inlet of the vertical hole).

[0009] Therefore, compared to conventional holding devices, the flow rate of gas flowing through the vertical hole can be increased. And because the diameter (opening area) of the vertical hole remains unchanged, the flow rate of gas supplied to the mounting surface can be increased without affecting the temperature distribution around the vertical hole on the mounting surface. This makes it possible to improve heat removal without worsening the uniformity of the temperature distribution on the mounting surface.

[0010] In the above-mentioned holding device, In the specific cross section, it is preferable that the side of the lateral hole opposite to the mounting surface side has a convex portion that protrudes toward the mounting surface side.

[0011] This increases the gas flow rate in the central portion of the horizontal hole where the vertical hole connects, thereby increasing the gas supply rate to the support surface, thereby enabling heat to be removed from the object in a shorter time and achieving a uniform temperature distribution on the support surface.

[0012] In any of the above-mentioned holding devices, In the specific cross section, it is preferable that at least one corner of the lateral hole is rounded.

[0013] Generally, corners of a flow path are prone to stress concentration, which can lead to cracks. Furthermore, when the cross section of the lateral hole is made convex toward the inside of the flow path as described above, the corners of the flow path cross section become acute, which particularly increases the risk of cracks occurring at the corners.

[0014] Therefore, by making at least one corner of the cross section of the lateral hole (preferably both corners that are convex inward of the flow path, and more preferably all corners) round, it is possible to prevent cracks from occurring at the corners. In particular, when the cross section of the lateral hole is convex inward of the flow path, it is possible to effectively suppress the occurrence of cracks at the corners of the lateral hole.

[0015] In any of the above-mentioned holding devices, In the specific cross section, it is preferable that the vertical hole has a larger communicating portion with the horizontal hole than an opening portion on the placement surface side.

[0016] By shaping the vertical hole in this way, the cross-sectional area of ​​the flow path at the portion where the vertical hole communicates with the horizontal hole (the gas inflow portion of the vertical hole) can be further increased, which in turn increases the flow rate of gas flowing through the vertical hole, thereby further increasing the flow rate of gas supplied to the mounting surface.

[0017] The opening on the mounting surface side refers to the area up to 1 / 4 of the longitudinal length from the mounting surface of the vertical hole, and the communicating portion with the horizontal hole refers to the portion of the vertical hole located 1 / 2 the height of the horizontal hole on the mounting surface side. In this way, the flow path cross-sectional area of ​​the vertical hole is not changed near the mounting surface (as in the conventional method) but is expanded near the area communicating with the horizontal hole, so the flow rate of gas supplied to the mounting surface can be increased without expanding the area of ​​temperature singularities that occur around the opening of the mounting surface. [Effects of the Invention]

[0018] According to the present disclosure, it is possible to provide a holding device that can increase the flow rate of gas supplied to the mounting surface without affecting the temperature distribution on the mounting surface. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck according to a first embodiment. [Figure 2] FIG. 2 is a schematic configuration diagram showing a gas flow path as viewed in the Z-axis direction. [Figure 3] 3 is a schematic configuration diagram of an XZ cross section of the electrostatic chuck taken along line III-III shown in FIG. 2. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing the cross-sectional shape of a lateral gas flow passage at a specific cross section. [Figure 5] 10A and 10B are diagrams showing modified examples of lateral gas flow passages. [Figure 6] FIG. 10 is an enlarged cross-sectional view showing the cross-sectional shape of a lateral gas flow passage in the electrostatic chuck of the second embodiment. [Figure 7] FIG. 10 is an enlarged cross-sectional view showing the cross-sectional shapes of a lateral gas flow path and a gas exhaust flow path in the electrostatic chuck according to the third embodiment; [Figure 8] FIG. 10 is a diagram showing a modified example of a gas discharge flow path. [Figure 9] FIG. 10 is a diagram showing another modified example of the gas discharge flow path. DETAILED DESCRIPTION OF THE INVENTION

[0020] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, the holding device will be described by taking as an example an electrostatic chuck used in semiconductor manufacturing equipment such as an etching device (such as a plasma etching device) or a film forming device (such as a CVD film forming device or a sputtering film forming device).

[0021] [First embodiment] First, an electrostatic chuck 1 according to a first embodiment will be described with reference to Figures 1 to 4. The electrostatic chuck 1 according to this embodiment is a device 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 Figure 1, the electrostatic chuck 1 includes a plate-shaped member 10, a base member 20, and a bonding layer 30 that bonds the plate-shaped member 10 and the base member 20 together.

[0022] 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 the axis in the axial direction of the electrostatic chuck 1 (the vertical direction in FIG. 1) and is an example of the "thickness direction" in the present disclosure. The X and Y axes are axes in the radial direction of the electrostatic chuck 1. Furthermore, the "planar direction" in the present disclosure refers to the direction of the XY plane extending perpendicular to the Z axis direction.

[0023] As shown in FIG. 1, the plate-shaped member 10 is a disk-shaped member having an upper surface, i.e., a mounting surface 11 on which a semiconductor wafer W is mounted, and a lower surface 12 located on the opposite side of the mounting surface 11 in the thickness direction (Z-axis direction) of the plate-shaped member 10. The plate-shaped member 10 is formed by firing a stack of ceramic green sheets or hot-pressing ceramic powder. Various ceramics are used to form the plate-shaped member 10, 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). The term "main component" as used herein refers to the component with the highest content (e.g., a component with a volume content of 90 vol% or more).

[0024] Here, the diameter of the plate-shaped member 10 is, for example, about 150 mm to 300 mm. The thickness of the plate-shaped member 10 is, for example, about 2 mm to 6 mm. The thermal conductivity of the plate-shaped member 10 is preferably in the range of 10 W / mK to 50 W / mK (more preferably, 18 W / mK to 30 W / mK).

[0025] 2 and 3, a gas flow path 40 is formed inside the plate-like member 10. The gas flow path 40 supplies an inert gas (e.g., He gas) to the minute space between the mounting surface 11 and the semiconductor wafer W mounted on the mounting surface 11. The gas flow path 40 includes a gas exhaust flow path 42, a lateral gas flow path 44, and a gas introduction flow path 46.

[0026] 3, the gas exhaust flow path 42 is a flow path that extends in the Z-axis direction, has one end connected to the horizontal gas flow path 44, and the other end open to the mounting surface 11. As shown in FIG. 2, a plurality of gas exhaust flow paths 42 (eight in this embodiment) are provided in the plate-like member 10. The gas exhaust flow paths 42 are an example of the "vertical hole" of the present disclosure.

[0027] As shown in Fig. 2, the lateral gas flow passage 44 is an annular flow passage formed in the XY plane direction when viewed in the Z-axis direction. The lateral gas flow passage 44 is an example of a "lateral hole" in the present disclosure. Note that the base member is omitted from Fig. 2.

[0028] 3, the gas introduction channel 46 is a channel that extends in the Z-axis direction, has one end that opens to the lower surface 12, and the other end that connects to the lateral gas channel 44. One gas introduction channel 46 is provided in the plate-shaped member 10.

[0029] In the gas flow path 40 having such a flow path configuration, first, an inert gas is supplied to the gas introduction flow path 46 from the lower side of the electrostatic chuck 1 (plate-like member 10). Then, the inert gas supplied to the gas introduction flow path 46 is discharged onto the mounting surface 11 via the lateral gas flow path 44 and each gas discharge flow path 42. As a result, the inert gas is filled into the minute space between the mounting surface 11 and the semiconductor wafer W.

[0030] 4 , in a specific cross section perpendicular to the longitudinal direction of the lateral gas flow passage 44 (X-axis or Y-axis direction: radial direction of the plate-like member 10) and including one gas exhaust flow passage 42, a side 44a on the mounting surface 11 side defining the lateral gas flow passage 44 is inclined with respect to a perpendicular line L perpendicular to the direction in which the gas exhaust flow passage 42 extends (Z-axis direction) so as to be substantially symmetrical with respect to the center of the gas exhaust flow passage 42 as a boundary line. On the other hand, a side 44b on the opposite side from the mounting surface 11 (the side toward the lower surface 12) defining the lateral gas flow passage 44 has a flat shape similar to that of a conventional electrostatic chuck. That is, at a portion of an upper surface 45u (side 44a) of the lateral gas flow passage 44 where the gas exhaust flow passage 42 is connected, the upper surface 45u of the lateral gas flow passage 44 is convex (convex downward in this embodiment). The upper surface 45u of the lateral gas flow passage 44 may be convex either upward or downward, and may be convex upward as shown in Fig. 5. The cross section shown in Fig. 4 is an example of a "specific cross section" in the present disclosure.

[0031] Such lateral gas channels 44 can be formed by firing the plate-shaped member 10 while the plate-shaped member 10 is in a green sheet state, while pressurizing or depressurizing the lateral gas channels 44. Specifically, by firing the plate-shaped member 10 while pressurizing the lateral gas channels 44, the upper surfaces 45u of the lateral gas channels 44 can be formed to be convex upward. On the other hand, by firing the plate-shaped member 10 while depressurizing the lateral gas channels 44, the upper surfaces 45u of the lateral gas channels 44 can be formed to be convex downward. Alternatively, the upper surfaces 45u of the lateral gas channels 44 can be formed to be convex downward by applying a higher pressure to the lateral gas channels 44 from the outside (vertical direction) of the plate-shaped member 10 while the plate-shaped member 10 is in a green sheet state. At this time, applying a higher pressure to the gas exhaust channels 42 can selectively form a convex upper surface 45u of the lateral gas channels 44 near where the gas exhaust channels 42 are connected. Alternatively, the upper surfaces 45u of the lateral gas channels 44 can be formed to be convex downward or upward by machining the upper surfaces 45u of the lateral gas channels 44 while the plate-shaped member 10 is in a green sheet state, followed by firing. When forming by hot pressing, a material that volatilizes when fired is formed into a convex shape and placed in the portion that will become the lateral gas flow channel 44, and then fired, so that the upper surface 45u of the lateral gas flow channel 44 can be formed convex after firing.

[0032] 4, at least one of the corners 44c of the lateral gas flow passage 44 is rounded. In this embodiment, the corner 44c on the upper side (the side facing the mounting surface 11) is rounded.

[0033] 3, the plate-like member 10 is provided therein with a chuck electrode 50. The chuck electrode 50 has, for example, a substantially circular shape as viewed in the Z-axis direction, and is made of a conductive material (for example, tungsten or molybdenum). The chuck electrode 50 is disposed over almost the entire area of ​​the mounting surface 11 (slightly smaller than the mounting surface 11) as viewed in the Z-axis direction. When a voltage is applied to the chuck electrode 50, an electrostatic attraction force (attraction force) is generated over the entire area of ​​the mounting surface 11, and the semiconductor wafer W is attracted and fixed to the mounting surface 11 by this electrostatic attraction force.

[0034] 1, the base member 20 is disposed on the opposite side of the plate-like member 10 from the mounting surface 11. The base member 20 is formed, for example, in a cylindrical shape. The base member 20 is preferably formed, for example, from a metal (for example, aluminum or an aluminum alloy), but may be formed from a material other than a metal (for example, ceramics).

[0035] 1 and 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 (i.e., the Z-axis direction) of the base member 20. The upper surface 21 of the base member 20 is thermally connected to the lower surface 12 of the plate-like member 10 via a bonding layer 30.

[0036] The diameter of the base member 20 is, for example, about 180 mm to 400 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 made of aluminum) is preferably within the range of 160 mm to 250 W / mK (preferably about 230 W / mK).

[0037] As shown in Figure 3, this base member 20 has a refrigerant flow path 23 formed therein for flowing a refrigerant (e.g., a fluorine-based inert liquid, water, etc.), and by flowing a refrigerant through this refrigerant flow path 23, the base member 20 is cooled, thereby cooling the plate-like member 10 via the bonding layer 30.

[0038] Furthermore, the base member 20 is formed with a gas introduction channel 26 that extends in the Z-axis direction, penetrates the base member 20, and opens to the upper surface 21 and the lower surface 22. The gas introduction channel 26 is disposed at a position that overlaps with the gas introduction channel 46 of the plate-like member 10 when viewed in the Z-axis direction, and is in communication with the gas introduction channel 46 via a through-hole 36 (see FIG. 3) formed in the bonding layer 30.

[0039] As shown in FIGS. 1 and 3, the bonding layer 30 is disposed between the lower surface 12 of the plate-shaped member 10 and the upper surface 21 of the base member 20, and bonds the plate-shaped member 10 and the base member 20 in a heat-transferable manner. The bonding layer 30 is made of a resin adhesive, 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 mm to 1.5 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 W / mK to 2.0 W / mK (preferably 0.5 W / mK to 1.5 W / mK).

[0040] Further, a through hole 36 that connects the gas introduction channel 26 and the gas introduction channel 46 is formed in the bonding layer 30. The through hole 36 is arranged at a position overlapping the gas introduction channel 26 and the gas introduction channel 46. As a result, the gas introduction channel 26, the through hole 36, and the gas introduction channel 46 are arranged in series in the Z-axis direction, forming a channel for supplying an inert gas to the lateral gas channel 44.

[0041] As described above, the electrostatic chuck 1 of this embodiment has the gas flow path 40 including the plurality of gas exhaust flow paths 42, the lateral gas flow path 44, and the gas introduction flow path 46. As a result, the inert gas supplied to the gas introduction flow path 26 from the outside (the lower surface 22 side of the base member 20) flows into the gas flow path 40 in the plate-shaped member 10, is discharged to the mounting surface 11 from the plurality of gas exhaust flow paths 42, and fills the minute space between the mounting surface 11 and the semiconductor wafer W.

[0042] In recent years, a high voltage has been increasingly applied to the electrostatic chuck (used at high power), and the temperature of the semiconductor wafer W held thereon tends to be higher than before. Therefore, there is a demand for heat dissipation properties (improved heat dissipation properties) that can reduce the temperature of the semiconductor wafer W in a short time without reducing the uniformity of the temperature distribution on the mounting surface 11.

[0043] 4, in the gas flow passage 40 formed in the plate-shaped member 10, in a specific cross section that is perpendicular to the longitudinal direction of the lateral gas flow passage 44 (X-axis or Y-axis direction: radial direction of the plate-shaped member 10) and includes one gas exhaust flow passage 42, a side 44a on the mounting surface 11 side that defines the lateral gas flow passage 44 is formed to be inclined with respect to a perpendicular line L that is perpendicular to the extension direction (Z-axis direction) of the gas exhaust flow passage 42. In this embodiment, an upper surface 45u of the lateral gas flow passage 44 is formed to be convex downward.

[0044] Therefore, the inlet (inlet area) of the gas exhaust passage 42 can be increased at the point where the gas exhaust passage 42 connects to the lateral gas passage 44 (the portion corresponding to the inlet of the gas exhaust passage). This makes it possible to increase the flow rate of gas flowing from the lateral gas passage 44 to the gas exhaust passage 42 compared to a conventional electrostatic chuck (where the upper surface of the lateral gas passage is flat). Therefore, the flow rate of gas in the gas exhaust passage 42 can be increased.

[0045] Furthermore, the diameter (opening area) of the gas exhaust flow path 42 remains unchanged. Therefore, the flow rate of gas supplied to the mounting surface 11 can be increased without affecting the temperature distribution around the gas exhaust flow path 42 on the mounting surface 11. This makes it possible to improve heat removal while maintaining the uniformity of the temperature distribution on the mounting surface 11.

[0046] Generally, stress concentration is likely to occur at the corners of the lateral gas flow passage, which may result in cracks. In particular, when the upper surface 45u of the lateral gas flow passage 44 is formed to be convex downward (i.e., the flow passage cross section is convex toward the inside of the flow passage), as in this embodiment, the corners 44c of the flow passage cross section become acute, which makes stress concentration more likely to occur, particularly increasing the risk of cracks occurring at the corners 44c.

[0047] Therefore, in the electrostatic chuck 1 of the present embodiment, the corners 44c on both sides of the upper surface 45u of the lateral gas flow passage 44, which is convex downward, are rounded, which can prevent cracks from occurring at the corners 44c.

[0048] As described above, according to the electrostatic chuck 1 of this embodiment, the upper surface 45u of the lateral gas flow passage 44 is formed to be convex downward without changing the diameter (opening area) of the gas exhaust flow passage 42. Therefore, the inlet of the gas exhaust flow passage 42 can be enlarged without widening the outlet of the gas exhaust flow passage 42 (the opening area of ​​the gas exhaust flow passage 42 on the mounting surface 11). Therefore, it is possible to improve heat dissipation while maintaining uniformity in the temperature distribution on the mounting surface 11.

[0049] [Second embodiment] Next, a second embodiment will be described. The second embodiment has the same basic configuration as the first embodiment, but the shape of the lateral gas flow path 44 is different from that of the first embodiment. Therefore, the same components as those in the first embodiment will be denoted by the same reference numerals and their description will be omitted as appropriate, and the description will focus on the differences from the first embodiment.

[0050] 6, in the electrostatic chuck 1a of the second embodiment, in a specific cross section, a side 44b defining the lateral gas flow passage 44 on the side opposite to the mounting surface 11 (i.e., the side toward the lower surface 12) has a convex portion that protrudes toward the mounting surface 11. That is, in this embodiment, an upper surface 45u of the lateral gas flow passage 44 is convex downward, and a lower surface 45d of the lateral gas flow passage 44 is convex upward. All corners 44c of the lateral gas flow passage 44 are rounded.

[0051] Therefore, according to the electrostatic chuck 1a of the second embodiment, the gas flow rate can be increased in the central portion of the lateral gas flow passage 44 where the gas exhaust flow passage 42 is connected. This increases the gas supply rate to the mounting surface 11. Therefore, in addition to the effects obtained in the first embodiment, heat can be removed from the semiconductor wafer W in a shorter time.

[0052] [Third embodiment] Finally, a third embodiment will be described. The third embodiment has the same basic configuration as the first embodiment, but differs from the first embodiment in the shape of the gas discharge flow path 42. Therefore, the same components as those in the first embodiment will be denoted by the same reference numerals and their description will be omitted as appropriate, and the description will focus on the differences from the first embodiment.

[0053] As shown in FIG. 7, in the electrostatic chuck 1b of the third embodiment, the cross-sectional area (diameter) of the gas exhaust passage 42 is larger at the communicating portion 42b with the lateral gas passage 44 than at the opening 42a on the mounting surface 11 side. For example, in the gas exhaust passage 42 of this embodiment, the diameter of the opening 42a is 0.3 mm, and the diameter of the communicating portion 42b is 0.3 to 0.45 mm (the diameter of the communicating portion 42b is 1.0 to 1.5 times that of the opening 42a). Note that, although the communicating portion 42b has an R-shape in this embodiment, the communicating portion 42b may have a tapered shape as shown in FIG. 8. Furthermore, as shown in FIG. 9, the communicating portion 42b may have a convex shape with a larger diameter than the gas exhaust passage 42.

[0054] By forming the gas exhaust flow path 42 in this shape, it is possible to further increase the flow path cross-sectional area at the communication portion 42b (gas inlet portion of the gas exhaust flow path 42) between the gas exhaust flow path 42 and the lateral gas flow path 44. This makes it possible to further increase the flow rate of gas flowing through the gas exhaust flow path 42, and therefore the flow rate of gas supplied to the mounting surface 11 can be further increased.

[0055] The opening 42a of the gas exhaust flow path 42 refers to a portion of the gas exhaust flow path 42 that is from the mounting surface 11 to 1 / 4A, where A is the length in the longitudinal direction (Z-axis direction) from the mounting surface 11 to a corner 44c of the lateral gas flow path 44 (the position on the upper surface 45u closest to the mounting surface 11). The communicating portion 42b with the lateral gas flow path 44 refers to a portion of the gas exhaust flow path 42 that is from the open end of the gas exhaust flow path 42 opposite the opening 42a (the connecting portion between the gas exhaust flow path 42 and the lateral gas flow path 44) to 1 / 2C, where C is the height of the lateral gas flow path 44 at the corner 44c (the distance from the bottom surface 45d to the corner 44c).

[0056] As described above, according to the electrostatic chuck 1b of the third embodiment, the cross-sectional area of ​​the gas exhaust passage 42 is not expanded at the opening 42a on the mounting surface 11 side, but is expanded at the communicating portion 42b that communicates with the lateral gas passage 44. Therefore, the flow rate of the gas supplied to the mounting surface 11 can be further increased without expanding the region of temperature singularities that occur around the opening of the gas exhaust passage 42 on the mounting surface 11. This makes it possible to remove heat from the semiconductor wafer W in an even shorter time, in addition to the effects obtained in the first embodiment.

[0057] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way, and various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. For example, in the above-described embodiments, the present disclosure is applied to an electrostatic chuck, but the present disclosure is not limited to electrostatic chucks and can be applied to any holding device that holds an object on its surface.

[0058] In addition, although the above description illustrates the first to third embodiments individually, the above embodiments may be combined as appropriate. For example, by combining the second embodiment with the third embodiment, the effects obtained in the second embodiment and the third embodiment can be synergistically obtained, so that the flow rate of gas supplied to the mounting surface 11 can be further increased, and heat dissipation performance can be further improved. [Explanation of symbols]

[0059] 1. Electrostatic chuck 10 Plate-shaped member 11 Placement surface 40 Gas flow path 42 Gas exhaust flow path 42a opening 42b Communication part 44 Horizontal gas flow path Around 44a Around 44b 44c Corner 45d Bottom 45u top 46 Gas introduction channel L perpendicular W Semiconductor wafer

Claims

1. a plate-like member having a placement surface on which an object to be held is placed; a gas flow path formed in the plate-shaped member for supplying an inert gas to the mounting surface; In a holding device having The gas flow path is a horizontal hole extending in a planar direction within the plate-like member; a plurality of vertical holes extending in a thickness direction of the plate-like member, one end of which communicates with the horizontal hole and the other end of which opens to the placement surface; In a specific cross section perpendicular to the longitudinal direction of the horizontal hole and including one of the vertical holes, The side of the placement surface that defines the horizontal hole is inclined with respect to a perpendicular line perpendicular to the direction in which the vertical hole extends. A holding device characterized by:

2. 2. The holding device according to claim 1, In the specific cross section, a side of the horizontal hole opposite to the mounting surface side has a convex portion protruding toward the mounting surface side. A holding device characterized by:

3. The holding device according to claim 1 or 2, At least one corner of the lateral hole is rounded in the specific cross section. A holding device characterized by:

4. The holding device according to claim 1 or 2, In the specific cross section, the vertical hole has a larger communicating portion with the horizontal hole than an opening portion on the placement surface side. A holding device characterized by:

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