Shaft end mounting structure

Abstract

A novel shaft end attachment structure is provided for attaching the end of a hollow ceramic shaft to a mounting base. [Solution] The shaft end mounting structure is a shaft end mounting structure for mounting the end of a hollow ceramic shaft (20) integrated with a ceramic plate (12) having a wafer mounting surface (12a) to an installation stand (102), and includes a sealing member (40) arranged between the end face (26) of the hollow ceramic shaft (20) and the installation stand (102), a female thread portion (30) provided on the inner surface (28) of the hollow ceramic shaft (20), and an installation member (50) having a male thread portion (60) that screws into the female thread portion (30) and attaches the hollow ceramic shaft (20) so as to attract it to the installation stand (102).

Description

[Technical Field]

[0001] The present invention relates to a shaft end mounting structure. [Background technology]

[0002] A conventional shaft end mounting structure for airtightly mounting the end of a hollow ceramic shaft integrated with a ceramic plate on which a wafer is placed to the periphery of a through-hole provided in the bottom plate of a chamber includes a ring member made of a metal material or a metal-ceramic composite material airtightly bonded to the end face of the hollow ceramic shaft via a metal layer, and a fastening member that penetrates the bottom plate and the sealing layer and fastens the ring member to the bottom plate while the ring member is placed on the periphery of the through-hole provided in the bottom plate of the chamber via a sealing layer (see, for example, Patent Document 1). This shaft end mounting structure can sufficiently airtightly separate the internal space of the chamber from the internal space of the hollow ceramic shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6085073 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned shaft end attachment structure has problems such as high costs due to the use of metal bonding. For this reason, a new shaft end attachment structure that does not require metal bonding has been desired.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its main object to provide a novel shaft end attachment structure for attaching the end of a hollow ceramic shaft to an installation base. [Means for solving the problem]

[0006] [1] The shaft end mounting structure of the present invention is A shaft end attachment structure for attaching an end of a hollow ceramic shaft, which is integrated with a ceramic plate having a wafer mounting surface, to an installation base, comprising: a seal member disposed between the end surface of the hollow ceramic shaft and the mounting base; a female screw portion provided on an inner peripheral surface of the hollow ceramic shaft; a mounting member having a male screw portion that is screwed into the female screw portion, the mounting member attaching the hollow ceramic shaft to the mounting base in a pulling manner; It is equipped with the following.

[0007] In this shaft end mounting structure, a seal member is placed between the end face of the hollow ceramic shaft and the mounting base, the male thread portion of the mounting member is threadedly engaged with the female thread portion on the inner surface of the hollow ceramic shaft, and the hollow ceramic shaft is pulled toward the mounting base using the mounting member, thereby mounting the shaft end to the mounting base. Such a shaft end mounting structure is not known in the past. Therefore, the present invention provides a novel shaft end mounting structure for mounting the end of a hollow ceramic shaft to a mounting base.

[0008] [2] The shaft end mounting structure of the present invention (the shaft end mounting structure described in [1] above) may further include a rotation stopper member that prevents the hollow ceramic shaft from rotating axially relative to the mounting member, and the inner peripheral surface of the hollow ceramic shaft and the outer peripheral surface of the mounting member may have rotation stopper arrangement holes in which the rotation stopper member is arranged at positions facing each other. In this way, by arranging the rotation stopper member in the rotation stopper arrangement hole, it is possible to prevent the hollow ceramic shaft from rotating axially (rotating around its axis) relative to the mounting member.

[0009] [3] In the shaft end attachment structure of the present invention (the shaft end attachment structure described in [2] above), a gap that can be used to remove the anti-rotation member may be provided on the installation base side between the inner peripheral surface of the hollow ceramic shaft and the outer peripheral surface of the attachment member. In this way, a jig or the like for removing the anti-rotation member can be inserted through this gap, making it relatively easy to remove the anti-rotation member.

[0010] [4] In the shaft end attachment structure of the present invention (the shaft end attachment structure described in any one of [1] to [3] above), the thread diameter (nominal diameter) of the male thread portion may be 35 mm or more and 65 mm or less, and the pitch of the male thread portion may be 10% or more and 20% or less of the thread diameter. The thread diameter and pitch of the female thread portion may be set appropriately within a range that allows engagement with the male thread portion. From the viewpoint of suppressing processing cracks, etc., a larger thread diameter and pitch are preferable, and from the viewpoint of space saving, a smaller thread diameter and pitch are preferable.

[0011] [5] In the shaft end mounting structure of the present invention (the shaft end mounting structure described in any one of [1] to [4] above), the mounting member may have a screw hole opening toward the installation base, and a bolt passing through the back surface of the installation base may be threaded into the screw hole to attract the hollow ceramic shaft to the installation base. In this way, the mounting member can be easily fixed to the installation base, and the end of the hollow ceramic shaft can be easily attached to the installation base.

[0012] [6] In the shaft end mounting structure of the present invention (the shaft end mounting structure described in any one of [1] to [5] above), the end face of the hollow ceramic shaft may have a sealing surface with a surface roughness Ra of 0.5 μm or less, and the sealing member may be disposed between the sealing surface and the mounting base. This allows the shaft end to be mounted to the mounting base with higher airtightness. The surface roughness Ra of the sealing surface is more preferably 0.2 μm or less.

[0013] [7] In the shaft end attachment structure of the present invention (the shaft end attachment structure described in any one of [1] to [6] above), the female thread portion may be provided within a range of 150 mm from the end face of the hollow ceramic shaft. This allows the hollow ceramic shaft to be attached to the installation base using a relatively short attachment member.

[0014] [8] In the shaft end mounting structure of the present invention (the shaft end mounting structure described in any one of [1] to [7] above), the thread diameter of the male threaded portion of the mounting member may be larger than the outer diameter of the portion of the male threaded portion that is closer to the installation base.

[0015] [9] In the shaft end mounting structure of the present invention (the shaft end mounting structure described in any one of [1] to [7] above), the thread diameter of the male thread portion of the mounting member may be equal to or smaller than the outer diameter of a portion closer to the installation base than the male thread portion. The portion of the mounting member closer to the installation base than the male thread portion may be a large diameter portion having a diameter larger than the thread diameter of the male thread portion. The large diameter portion may be disposed in an enlarged diameter portion provided on the hollow ceramic shaft, or may be disposed between the end face of the hollow ceramic shaft and the installation base.

[0016]

[10] In the shaft end mounting structure of the present invention (the shaft end mounting structure described in any one of [1] to [7] above), the mounting member may have a male thread portion over the entire outer circumferential surface.

[0017]

[11] The shaft end attachment structure of the reference invention disclosed by reference in this specification is: A shaft end attachment structure for attaching an end of a hollow ceramic shaft, which is integrated with a ceramic plate having a wafer mounting surface, to an installation base, comprising: a seal member disposed between the end surface of the hollow ceramic shaft and the mounting base; a shaft inner peripheral groove provided around the inner peripheral surface of the hollow ceramic shaft; a mounting unit including a mounting member having a mounting member outer circumferential groove provided to face the shaft inner circumferential groove, and a plurality of holding members each arranged across the shaft inner circumferential groove and the mounting member outer circumferential groove and spaced apart from each other in the circumferential direction, the mounting unit attaching the hollow ceramic shaft to the installation base in a manner that pulls the hollow ceramic shaft to the installation base; It is equipped with the following.

[0018] In this shaft end attachment structure, a seal member is placed between the end face of the hollow ceramic shaft and the installation base. The hollow ceramic shaft is attached to the installation base by pulling it to the installation base via a retaining member positioned across the shaft inner circumferential groove and the installation member outer circumferential groove. To attach the shaft end to the installation base, first, multiple retaining members are gathered and arranged in one location in the shaft inner circumferential groove or the installation member outer circumferential groove, and then the installation member is inserted into the hollow ceramic shaft. By gathering and arranging the retaining members in one location in the groove, a gap is created through which the installation member can be inserted until the installation member outer circumferential groove faces the shaft inner circumferential groove with the retaining members positioned in the groove. Once the installation member outer circumferential groove faces the shaft inner circumferential groove, the installation member is moved coaxially with the hollow ceramic shaft while the retaining members are moved within the groove to be spaced approximately evenly. Placing the retaining members approximately evenly narrows the gap, preventing the installation member from slipping out of the hollow ceramic shaft. This allows the hollow ceramic shaft to be pulled to the installation base via the retaining members. Such a shaft end attachment structure is not known in the past. Therefore, the reference invention can provide a novel shaft end attachment structure for attaching the end of a hollow ceramic shaft to an installation base.

[0019]

[12] In the shaft end attachment structure of the reference invention (the shaft end attachment structure described in

[11] above), the holding member may be circular when viewed from the installation base side. This allows the holding member to move smoothly within the shaft inner circumferential groove and the attachment member outer circumferential groove. The holding member may be, for example, spherical, cylindrical, or disk-shaped. Cylindrical or disk-shaped members may have a bulge or depression in the center of at least one of the side and top / bottom surfaces.

[0020]

[13] The shaft end attachment structure of the reference invention (the shaft end attachment structure described in

[11] or

[12] above) may further include an auxiliary member that maintains the spacing between the retaining members within the shaft inner circumferential groove and the mounting member outer circumferential groove. The auxiliary member may have a structure similar to that of a cage used to hold rolling elements in the field of bearings, for example.

[0021]

[14] The shaft end mounting structure of the reference invention (the shaft end mounting structure described in any one of

[11] to

[13] above) may further include a rotation stopper member that prevents the hollow ceramic shaft from rotating axially relative to the mounting member, and the inner surface of the hollow ceramic shaft and the outer surface of the mounting member may have rotation stopper arrangement holes in which the rotation stopper member is arranged at positions facing each other.

[0022]

[15] In the shaft end mounting structure of the reference invention (the shaft end mounting structure described in

[14] above), a gap may be provided between the inner surface of the hollow ceramic shaft and the outer surface of the mounting member on the installation base side that can be used to remove the rotation stop member.

[0023]

[16] In the shaft end mounting structure of the reference invention (the shaft end mounting structure described in any one of

[11] to

[15] above), the mounting member may have a screw hole opening toward the installation base, and a bolt passing through the back surface of the installation base may be screwed into the screw hole to attract the hollow ceramic shaft to the installation base via the retaining member.

[0024]

[17] In the shaft end mounting structure of the reference invention (the shaft end mounting structure described in any one of

[11] to

[16] above), the end face of the hollow ceramic shaft may have a sealing surface with a surface roughness Ra of 0.5 μm or less, and the sealing member may be arranged between the sealing surface and the installation base.

[0025]

[18] In the shaft end mounting structure of the reference invention (the shaft end mounting structure described in any one of

[11] to

[17] above), the shaft inner circumferential groove may be provided within a range of 150 mm from the end face of the hollow ceramic shaft. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing an example of a shaft end attachment structure of the present invention. [Figure 2] 1 is a bottom view of the hollow ceramic shaft 20 and the mounting member 50. FIG. [Figure 3] FIG. 4 is an explanatory diagram showing an example of a shaft end attachment step of the present invention. [Figure 4] FIG. 10 is a cross-sectional view showing another example of the shaft end attachment structure of the present invention. [Figure 5] FIG. 10 is a cross-sectional view showing another example of the shaft end attachment structure of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing an example of a shaft end attachment structure according to the present invention. [Figure 7] 2 is a bottom view of the hollow ceramic shaft 220 and the mounting unit 240. FIG. [Figure 8] FIG. 10 is an explanatory diagram showing an example of a shaft end attachment process of the reference invention. [Figure 9] FIG. 10 is a cross-sectional view showing another example of a shaft end attachment structure according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] [Embodiment] First, a preferred embodiment of the shaft end mounting structure of the present invention will be described below with reference to Figures 1 and 2. Figure 1 is a cross-sectional view showing an example of the shaft end mounting structure of the present invention, specifically a cross-sectional view of a ceramic heater 10 mounted inside a chamber 100 (a cross-sectional view cut along a plane passing through the central axis of a hollow ceramic shaft 20). Figure 2 is a bottom view of the hollow ceramic shaft 20 and mounting member 50 (viewed from the installation table 102 side). Note that Figure 1 corresponds to the AA cross section of Figure 2.

[0028] The ceramic heater 10 is used to heat a wafer W and is mounted inside a semiconductor process chamber 100. Specifically, the ceramic heater 10 is fixed to a mounting table 102 provided at the bottom of the chamber 100 using a mounting member 50. A seal member 40 is disposed between an end face 26 of the ceramic heater 10 and the mounting table 102. The ceramic heater 10 includes a ceramic plate 12 having a wafer mounting surface 12a on which a wafer W can be mounted, and a hollow ceramic shaft 20 joined to a surface (back surface) 12b of the ceramic plate 12 opposite the wafer mounting surface 12a.

[0029] The ceramic plate 12 is a disk-shaped member (e.g., 300 mm in diameter) made of ceramic, such as aluminum nitride or alumina. A heater electrode 14 and an RF electrode 16 are embedded in the ceramic plate 12. The heater electrode 14 is a coil made primarily of a high-melting-point metal, such as Mo or W, or its carbide, wired in a single stroke across the entire surface of the ceramic plate 12. One end of the heater electrode 14 is connected to a positive heater terminal rod 14a, and the other end is connected to a negative heater terminal rod 14b. The RF electrode 16 is a disk-shaped thin-layer electrode with a diameter slightly smaller than that of the ceramic plate 12. It is formed of a sheet-shaped mesh made by weaving thin metal wires, mainly made of a high-melting-point metal, such as Mo or W, or its carbide. The RF electrode 16 is embedded in the ceramic plate 12 between the heater electrode 14 and the wafer-mounting surface 12a. Furthermore, an RF terminal rod 16a is connected to the approximate center of the RF electrode 16.

[0030] The hollow ceramic shaft 20 is a cylindrical member made of ceramic, typically aluminum nitride or alumina, and has a first flange 22 around the upper opening and a second flange 24 around the lower opening. The end face on the first flange 22 side is diffusion-bonded to the back surface 12b of the ceramic plate 12. The end face 26 on the second flange 24 side is placed on the installation base 102 via a seal member 40. An internal thread 30 is provided on an inner peripheral surface 28 of the hollow ceramic shaft 20. The thread diameter (nominal diameter) of the internal thread 30 is, for example, 35 mm or more and 65 mm or less. The pitch of the internal thread 30 is, for example, 10% or more and 20% or less of the thread diameter. The thread diameter (nominal diameter) of the internal thread 30 is equal to or less than the inner diameter of the portion of the hollow ceramic shaft 20 closer to the installation base 102 than the internal thread 30. The internal thread 30 is provided, for example, within a range of 150 mm from the end face 26 of the hollow ceramic shaft 20. The wall thickness (radial length of the hollow ceramic shaft 20) of the hollow ceramic shaft 20 is, for example, 1.5 mm or more and 10.0 mm or less at its thinnest part. The heater terminal rods 14a, 14b and the RF terminal rod 16a are inserted into the internal space S2 of the hollow ceramic shaft 20.

[0031] The seal member 40 is an elastically deformable annular member and is arranged coaxially with the hollow ceramic shaft 20. The seal member 40 is compressed between the hollow ceramic shaft 20 and the mounting base 102 to seal the gap between them and improve the airtightness between the internal space S1 of the chamber 100 and the internal space S2 of the hollow ceramic shaft 20. An O-ring, a packing, or the like can be used as the seal member 40. The seal member 40 may be made of an insulating material or a conductive material. The seal member 40 may be made of resin, rubber, or metal.

[0032] The mounting member 50 is a member having an internal space for passing various terminal rods and wiring, and is an annular member in this example. The mounting member 50 is disposed coaxially with the hollow ceramic shaft 20. The mounting member 50 may be made of a metal such as aluminum, a ceramic such as alumina, quartz, or a composite material of metal and ceramic such as Si-SiC. The mounting member 50 may also be made of resin. An external thread portion 60 is provided on an outer peripheral surface 58 of the mounting member 50 and is threadedly engaged with the internal thread portion 30. The thread diameter (nominal diameter) of the external thread portion 60 is, for example, 35 mm or more and 65 mm or less. The pitch of the external thread portion 60 is, for example, 10% or more and 20% or less of the thread diameter. The thread diameter (nominal diameter) of the external thread portion 60 is larger than the outer diameter of the portion of the mounting member 50 that is closer to the installation base 102 than the external thread portion 60. The wall thickness of the mounting member 50 (the length between the inner peripheral surface 56 and the outer peripheral surface 58) is, for example, 1.0 mm or more and 10.0 mm or less at its thinnest portion. The mounting member 50 has one or more (preferably two or more, three or more, eight in this embodiment) screw holes 54 opening toward the mounting base 102. A bolt 70 passing through the rear surface of the mounting base 102 is threaded into each screw hole 54, thereby attracting the mounting member 50 to the mounting base 102. The hollow ceramic shaft 20 threaded into the mounting member 50 is attracted to the mounting base 102 via the mounting member 50. The outer diameter of the portion of the mounting member 50 closer to the mounting base 102 than the male thread portion 60 is smaller than the inner diameter of the portion of the hollow ceramic shaft 20 closer to the mounting base 102 than the female thread portion 30. Therefore, a gap G is formed between the inner peripheral surface 28 of the hollow ceramic shaft 20 and the outer peripheral surface 58 of the mounting member 50.

[0033] This shaft end mounting structure includes a rotation stopper member 75 that prevents the hollow ceramic shaft 20 from rotating axially relative to the mounting member 50. The rotation stopper member 75 is a wedge-shaped member with a narrow upper surface 75a and a wide lower surface 75b (see FIG. 3). The rotation stopper member 75 may be made of metal, ceramic, resin, or a composite material thereof. The inner circumferential surface 28 of the hollow ceramic shaft 20 and the outer circumferential surface 58 of the mounting member 50 have rotation stopper arrangement holes 35, 65 at positions facing each other, and the rotation stopper member 75 is disposed across the rotation stopper arrangement holes 35, 65. The rotation stopper arrangement hole 35 is a rectangular parallelepiped groove that opens to the inner circumferential surface 28 and the end face 26 of the hollow ceramic shaft 20. The rotation stopper arrangement hole 65 is a rectangular parallelepiped groove that opens to the outer circumferential surface 58 and the end face 66 of the mounting member 50. The groove width of the rotation stopper arrangement holes 35, 65 is slightly smaller than the width of the underside 75b of the rotation stopper member 75, so that the rotation stopper member 75 fitted into the rotation stopper arrangement holes 35, 65 will not fall out. When removing the rotation stopper member 75, a jig or the like for removing the rotation stopper member 75 may be inserted into the gap G between the inner peripheral surface 28 of the hollow ceramic shaft 20 and the outer peripheral surface 58 of the mounting member 50, and the member may be pinched and pulled out with the jig or scraped out with the jig.

[0034] Next, an example of the shaft end attachment step will be described below with reference to Fig. 3. Fig. 3 is an explanatory diagram showing an example of the shaft end attachment step of the present invention, and in particular an explanatory diagram of the step of attaching the hollow ceramic shaft 20 to the installation stage 102. Note that Figs. 3A to 3D omit parts of the chamber 100 other than the installation stage 102, the heater electrode 14, the heater terminal rods 14a and 14b, the RF electrode 16, and the RF terminal rod 16a.

[0035] In the shaft end attachment process, first, the ceramic heater 10 is prepared, and the attachment member 50 is inserted into the hollow ceramic shaft 20 from the end face 26 side (FIG. 3A). When the male thread portion 60 reaches the height of the female thread portion 30, the attachment member 50 is rotated around its axis to screw the male thread portion 60 into the female thread portion 30. Then, when the rotation stopper arrangement holes 35, 65 are positioned opposite each other, the rotation stopper member 75 is inserted into the rotation stopper arrangement holes 35, 65 (FIG. 3B). Next, the ceramic heater 10 and the attachment member 50 are placed on the installation base 102 so that the internal space S2 of the hollow ceramic shaft 20 communicates with the through-hole 104 of the installation base 102 (FIG. 3C). At this time, a seal member 40 is placed between the end face 26 of the hollow ceramic shaft 20 and the installation base 102. The attachment member 50 is also placed so that the screw holes 54 are connected to the bolt insertion holes 106 of the installation base 102. The bolt insertion holes 106 may or may not be threaded. Finally, the bolts 70 are inserted into the bolt insertion holes 106 from the back surface of the installation base 102 and screwed into the threaded holes 54 of the mounting member 50 (FIG. 3D). At this time, the bolts are screwed in such a way that the fastening force is not biased and the seal member 40 is sufficiently crushed. In this way, the end of the hollow ceramic shaft 20 can be attached to the installation base 102. Note that the attachment of the heater terminal rods 14a, 14b to the heater electrode 14 and the attachment of the RF terminal rod 16a to the RF electrode 16 may be performed before or after the shaft end attachment process.

[0036] Next, an example of how the ceramic heater 10 of this embodiment is used will be described. A wafer W is placed on the wafer mounting surface 12a of the ceramic heater 10, and the internal space S1 of the chamber 100 is set to a predetermined atmosphere (e.g., a hydrogen atmosphere, an argon atmosphere, or a vacuum atmosphere). At this time, the internal space S1 is isolated from the internal space S2 of the hollow ceramic shaft 20. A semiconductor process, such as wafer annealing, is performed on the wafer W by applying a voltage to the heater electrode 14 via the heater terminal rods 14a and 14b. Alternatively, if necessary, a high AC voltage can be applied to the RF electrode 16 via the RF terminal rod 16a to generate plasma between parallel plate electrodes consisting of an opposing horizontal electrode (not shown) installed above the chamber 100 and the RF electrode 16 embedded in the ceramic heater 10, and the plasma can be utilized. During wafer W processing, a high DC voltage can be applied to the RF electrode 16 to generate an electrostatic force, which attracts the wafer W to the wafer mounting surface 12a.

[0037] In the shaft end mounting structure of this embodiment described above in detail, the seal member 40 is disposed between the end face 26 of the hollow ceramic shaft 20 and the mounting base 102, the female thread portion 30 on the inner peripheral surface 28 of the hollow ceramic shaft 20 is threadedly engaged with the male thread portion 60 on the outer peripheral surface 58 of the mounting member 50, and the hollow ceramic shaft 20 is pulled toward the mounting base 102 using the mounting member 50, thereby mounting the shaft end to the mounting base 102. Such a shaft end mounting structure is not known in the past. Therefore, this embodiment provides a novel shaft end mounting structure for mounting the end of the hollow ceramic shaft 20 to the mounting base 102. Furthermore, since there is no need to use expensive metal joining in the shaft end mounting structure, costs can be reduced.

[0038] Furthermore, a rotation stopper member 75 is disposed in the rotation stopper arrangement holes 35, 65 provided on the inner peripheral surface 28 of the hollow ceramic shaft 20 and the outer peripheral surface 58 of the mounting member 50. Therefore, the axial rotation of the hollow ceramic shaft 20 relative to the mounting member 50 can be suppressed.

[0039] Furthermore, a gap G is provided on the installation base 102 side between the inner peripheral surface 28 of the hollow ceramic shaft 20 and the outer peripheral surface 58 of the mounting member 50. This gap G can be used to remove the rotation stop member 75 relatively easily.

[0040] Furthermore, if the thread diameter of the male thread portion 60 is 35 mm or more and the pitch of the male thread portion 60 is 10% or more of the thread diameter, it is possible to suppress processing cracks, etc. Also, if the thread diameter of the male thread portion 60 is 65 mm or less and the pitch of the male thread portion 60 is 20% or less of the thread diameter, it is possible to save space.

[0041] The mounting member 50 is fixed to the installation base 102 with bolts 70. This allows the mounting member 50 to be easily fixed to the installation base 102, making it possible to easily attach the end of the hollow ceramic shaft 102 to the installation base 102. Furthermore, axial rotation of the mounting member 50 and the hollow ceramic shaft 20 relative to the installation base 102 can be suppressed.

[0042] Alternatively, the end face 26 of the hollow ceramic shaft 20 may have a sealing surface with a surface roughness Ra of 0.5 μm or less, and the sealing member 40 may be disposed between the sealing surface of the end face 26 and the mounting base 102. Alternatively, the mounting base 102 may have a sealing surface with a surface roughness Ra of 0.5 μm or less, and the sealing member 40 may be disposed between the end face 26 and the sealing surface of the mounting base 102. This allows the shaft end to be attached to the mounting base 102 with higher airtightness. It is more preferable that the surface roughness Ra of the sealing surfaces of the end face 26 and the mounting base 102 be 0.2 μm or less.

[0043] Furthermore, the female screw portion 30 may be provided within a range of 150 mm (preferably 100 mm) from the end face of the hollow ceramic shaft 20. In this way, the hollow ceramic shaft 20 can be attached to the installation base 102 with a relatively short attachment member 50.

[0044] The axial length of the hollow ceramic shaft 20 may be, for example, 150 mm or more. This keeps the temperature of the shaft end relatively low, making it less likely that problems will arise with the heat resistance of the seal member 40.

[0045] Furthermore, the hollow ceramic shaft 20 is not directly attached to the installation base 102 with bolts 70 or the like, but is attached to the installation base 102 using mounting members 50. Therefore, there is no need to cut fine threads for the bolts 70 into the hollow ceramic shaft 20, and damage to the hollow ceramic shaft 20 due to thread cutting can be suppressed.

[0046] Furthermore, since the mounting member 50 is disposed on the internal space S2 side of the hollow ceramic shaft 20 (more inward than the seal member 40) rather than on the internal space S1 side of the chamber 100, corrosion of the mounting member 50 is unlikely to occur. This allows for greater freedom in selecting the material of the mounting member 50, and also reduces the cost of making the mounting member 50 corrosion-resistant.

[0047] It goes without saying that the present invention is not limited to the above-described embodiment, and can be embodied in various forms as long as they fall within the technical scope of the present invention.

[0048] For example, the shaft end mounting structure may be the shaft end mounting structure shown in FIG. 4 (FIGS. 4A to 4D). FIG. 4 is a cross-sectional view (cut along the same cross section as FIG. 1) showing another example of the shaft end mounting structure of the present invention. Components less relevant to the shaft end mounting structure are omitted from FIG. 4. As shown in FIG. 4A, at least one of the first flange 22 and the second flange 24 may be omitted. Also, as shown in FIG. 4A, a protrusion 108 that is one step higher than the surface on which the seal member 40 is disposed may be provided on the inner circumferential side of the mounting base 102 relative to the seal member 40. Providing the protrusion 108 facilitates positioning of the seal member 40. Also, as shown in FIGS. 4B and 4C, the thread diameter of the male thread portion 60 of the mounting member 50 may be equal to or smaller than the outer diameter of the portion of the mounting base 102 closer to the male thread portion 60. In FIGS. 4B and 4C, the portion of the mounting member 50 closer to the mounting base 102 relative to the male thread portion 60 is a large-diameter portion 62. The large diameter portion 62 may be disposed in the expanded diameter portion 32 provided on the end face 26 side of the hollow ceramic shaft 20 as shown in FIG. 4B , or may be disposed between the end face 26 of the hollow ceramic shaft 20 and the mounting base 102 as shown in FIG. 4C . In FIG. 4B , a clearance exceeding 0 mm may be provided between the portion of the hollow ceramic shaft 20 closer to the mounting base 102 than the female thread portion 30 and the portion of the mounting member 50 closer to the mounting base 102 than the male thread portion 60. Providing this clearance facilitates mounting of the mounting member 50. The clearance may be 0.5 mm or less. This clearance may be filled with an adhesive or the like. Alternatively, as shown in FIG. 4D , the entire outer circumferential surface 58 of the mounting member 50 may be provided with the male thread portion 60. In FIG. 4D , the hollow ceramic shaft 20 has an expanded diameter portion 32, and the female thread portion 30 is provided in the expanded diameter portion 32. 4D, the bolt 70 is inserted through the bolt insertion hole 106 that penetrates the installation base 102, the screw hole 54 that penetrates the mounting member 50, and the hole 36 (not threaded) that is provided in the hollow ceramic shaft 20 at a position facing the screw hole 54. When the bolt 70 is inserted into the hole 36, the bolt 70 functions as a rotation stopper that prevents the hollow ceramic shaft 20 from rotating about its axis relative to the mounting member 50.4B and 4C, the screw hole 54 may penetrate the large diameter portion 62 of the mounting member 50, and an unthreaded hole may be provided in the hollow ceramic shaft 20 at a position opposite the screw hole 54, with the bolt 70 being inserted into this hole and used as a rotation-stopping member. Note that in FIG. 4D, the hole 36 may be omitted, and the screw hole 54 may not penetrate the mounting member 50. Also, in FIG. 4D, a female thread portion 30 may be provided on the inner peripheral surface 28 of a hollow ceramic shaft 20 that does not have an expanded diameter portion 32.

[0049] The shaft end mounting structure may be the shaft end mounting structure shown in FIG. 5. FIG. 5 is a cross-sectional view (cut along the same cross section as FIG. 1) showing another example of the shaft end mounting structure of the present invention. In FIG. 5, components that are less relevant to the shaft end mounting structure are omitted. As shown in FIG. 5, the mounting member 50 may have a flange portion 68 on the end face 66 side, and may be configured so that the mounting base 102 is sandwiched between the flange portion 68 and the hollow ceramic shaft 20. In this way, the hollow ceramic shaft 20 can be mounted to the mounting base 102 without using bolts 70, thereby reducing the number of parts. A similar configuration can be adopted in the shaft end mounting structure of FIG. 4.

[0050] In the above-described embodiment, the rotation stop member 75 is used, but the rotation stop member 75 may be omitted. Also, in the above-described embodiment, one rotation stop member 75 is provided, but two or more rotation stop members may be provided. Also, the shape and arrangement of the rotation stop member 75 may be set appropriately.

[0051] In the above-described embodiment, the heater electrode 14 and the RF electrode 16 are embedded in the ceramic plate 12, but at least one of them may be omitted. Also, an electrostatic electrode may be embedded in place of the heater electrode 14 or the RF electrode 16.

[0052] In the above-described embodiment, the heater terminal rods 14a and 14b and the RF terminal rod 16a are used, but a flexible metal wire may be used instead of the rods. In this case, a metal terminal may be provided on at least one of both ends of the metal wire.

[0053] In the above-described embodiment, the mounting member 50 is directly attached to the installation base 102, but other parts may be interposed between the mounting member 50 and the installation base 102.

[0054] In the above-described embodiment, at least one of the inner peripheral surface 56 and the end surface 66 of the mounting member 50 may be provided with at least one of a protrusion and a recess as an attachment aid. For example, by hooking a mounting jig onto the protrusion or inserting it into the recess and using the mounting jig to rotate the mounting member 50 around its axis, the male threaded portion 60 can be relatively easily threaded all the way into the female threaded portion 30, even if the entire mounting member 50 is disposed inside the hollow ceramic shaft 20, as shown in FIGS. 4A, 4B, and 4D. The shape of the protrusion and recess may be, for example, a rectangular parallelepiped. Note that the screw hole 54 or the rotation stopper arrangement hole 65 may also be used as an attachment aid.

[0055] [Reference form] Next, a preferred embodiment (reference embodiment) of the shaft end mounting structure of the reference invention will be described below with reference to Figures 6 and 7. Figure 6 is a cross-sectional view showing an example of the shaft end mounting structure of the reference invention, specifically a cross-sectional view of a ceramic heater 210 mounted on an installation stand 102 (a cross-sectional view cut along a plane passing through the central axis of the hollow ceramic shaft 220). Figure 7 is a bottom view (viewed from the installation stand 102 side) of the hollow ceramic shaft 220 and the mounting unit 240. Note that Figure 6 corresponds to the cross section BB in Figure 7. In Figures 6 and 7, components similar to those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0056] The ceramic heater 210 is used to heat a wafer W and is mounted inside a semiconductor process chamber 100, similar to FIG. 1. Specifically, the ceramic heater 210 is fixed to a mounting table 102 provided at the bottom of the chamber 100 using a mounting unit 240. A seal member 40 is disposed between an end surface 26 of the ceramic heater 210 and the mounting table 102. The ceramic heater 210 includes a ceramic plate 12 having a wafer mounting surface 12a on which a wafer W can be mounted, and a hollow ceramic shaft 220 joined to a surface (back surface) 12b of the ceramic plate 12 opposite the wafer mounting surface 12a.

[0057] The hollow ceramic shaft 220 is configured similarly to the hollow ceramic shaft 20, except that a shaft inner circumferential groove 230 is provided instead of the female thread portion 30. The shaft inner circumferential groove 230 is an annular groove provided around the inner circumferential surface 28 of the hollow ceramic shaft 220. The cross-sectional shape of the shaft inner circumferential groove 230 can be, for example, semicircular or rectangular (the groove bottom may be C-chamfered or R-chamfered).

[0058] The mounting unit 240 includes a mounting member 250 and multiple (preferably three or more, six in this example) holding members 265. The mounting member 250 has a similar configuration to the mounting member 50, except that a mounting member outer circumferential groove 260 is provided instead of the male thread portion 60. The mounting member outer circumferential groove 260 is an annular groove provided around the outer circumferential surface 58 of the mounting member 250. The cross-sectional shape of the mounting member outer circumferential groove 260 may be, for example, semicircular or rectangular (the groove bottom may be C-chamfered or R-chamfered). The holding member 265 is, for example, a small circular piece when viewed from the installation base 102 side. In this example, the holding member 265 is a disk-shaped piece with a bulging central portion of the peripheral side surface. The outer diameter of the holding member 265 is, for example, 2 mm or more and 10 mm or less, and the height of the holding member 265 is, for example, 2 mm or more and 10 mm or less. The retaining members 265 are each disposed across the shaft inner circumferential groove 230 and the attachment member outer circumferential groove 260, and are disposed at equal intervals in the circumferential direction from one another. The retaining members 265 may be made of, for example, metal, ceramic, resin, or a composite material thereof. The cross-sectional shapes and dimensions of the shaft inner circumferential groove 230 and the attachment member outer circumferential groove 260 may be set appropriately depending on the shape and dimensions of the retaining members 265.

[0059] Next, an example of the shaft end attachment process will be described below with reference to Fig. 8. Fig. 8 is an explanatory diagram showing an example of the shaft end attachment process of the reference invention, and in particular, an explanatory diagram of the process of attaching the attachment unit 240 to the hollow ceramic shaft 220.

[0060] In the shaft end attachment process, first, the ceramic heater 210 is prepared, and multiple holding members 265 are arranged in one location in the shaft inner circumferential groove 230 of the hollow ceramic shaft 220. In this state, the attachment member 250 is inserted into the hollow ceramic shaft 220 (FIG. 8A). Once the attachment member outer circumferential groove 260 faces the shaft inner circumferential groove 230, the attachment member 250 is moved coaxially with the hollow ceramic shaft 220 (FIG. 8B), and the holding members 265 are moved within the groove to be arranged at approximately equal intervals (FIG. 8C). Then, the rotation stopper arrangement holes 35, 65 are aligned with each other, and the rotation stopper arrangement holes 35, 65 are inserted into the rotation stopper arrangement holes 35, 65 (FIG. 8C). Thereafter, the end of the hollow ceramic shaft 220 is attached to the installation base 102 in the same manner as in FIGS. 3C and 3D.

[0061] The use example of the ceramic heater 210 of the reference embodiment is similar to the use example of the ceramic heater 10 of the embodiment.

[0062] In the shaft end mounting structure of the reference embodiment described above in detail, the seal member 40 is disposed between the end face 26 of the hollow ceramic shaft 220 and the mounting base 102, and the shaft end is mounted to the mounting base 102 by attracting the hollow ceramic shaft 220 to the mounting base 102 via the retaining member 265 disposed across the shaft inner circumferential groove 230 and the mounting member outer circumferential groove 260. Such a shaft end mounting structure has not been known in the past. Therefore, the reference embodiment can provide a novel shaft end mounting structure for mounting the end of a hollow ceramic shaft to a mounting base.

[0063] Furthermore, since the holding member 265 has a circular shape when viewed from the installation base 102 side, the holding member 265 can be moved smoothly within the shaft inner peripheral groove 230 and the attachment member outer peripheral groove 260 .

[0064] In the above-described embodiment, an auxiliary member may be provided to maintain the spacing between the holding members 265 in the shaft inner circumferential groove 230 and the mounting member outer circumferential groove 260.

[0065] The shaft end mounting structure may be the shaft end mounting structure shown in FIG. 9 (FIGS. 9A and 9B). FIG. 9 is a cross-sectional view (cut along the same cross section as FIG. 6) showing another example of the shaft end mounting structure of the reference invention. As shown in FIG. 9A, at least one of the first flange 22 and the second flange 24 may be omitted. Also, as shown in FIG. 9A, a protrusion 108 that is one step higher than the surface on which the seal member 40 is disposed may be provided on the portion of the installation base 102 that is more inward than the seal member 40. Also, as shown in FIG. 9B, the entire outer circumferential surface 58 of the mounting member 250 may be formed with a mounting member outer circumferential groove 260. In FIG. 9B, the hollow ceramic shaft 220 has an expanded diameter portion 32, and the expanded diameter portion 32 is provided with a shaft inner circumferential groove 230. 9B, the bolt 70 is inserted through the bolt insertion hole 106 penetrating the installation base 102, the screw hole 54 penetrating the mounting member 250, and the hole 36 (not threaded) provided in the hollow ceramic shaft 220 at a position facing the screw hole 54. When the bolt 70 is inserted into the hole 36, the bolt 70 functions as a rotation stopper that prevents the hollow ceramic shaft 20 from rotating axially relative to the mounting member 50. In FIG. 9B, the hole 36 may be omitted, and the screw hole 54 may not penetrate the mounting member 250. In FIG. 9B, a shaft inner circumferential groove 230 may be provided on the inner circumferential surface 28 of the hollow ceramic shaft 220 that does not have the expanded diameter portion 32.

[0066] In the above-described embodiment, the various configurations described in the above-described embodiment and its modifications may be appropriately adopted. [Industrial Applicability]

[0067] The present invention can be used in semiconductor manufacturing equipment components such as ceramic heaters, electrostatic chucks, and susceptors. [Explanation of symbols]

[0068] 10 ceramic heater, 12 ceramic plate, 12a wafer mounting surface, 12b back surface, 14 heater electrode, 14a, 14b heater terminal rod, 16 RF electrode, 16a RF terminal rod, 20 hollow ceramic shaft, 22 first flange, 24 second flange, 26 end face, 28 inner peripheral surface, 30 female thread portion, 32 enlarged diameter portion, 35 rotation stopper arrangement hole, 36 hole, 40 seal member, 50 mounting member, 54 screw hole, 56 inner peripheral surface, 58 outer peripheral surface, 60 male thread portion, 62 large diameter portion, 65 rotation stopper arrangement hole, 66 end face, 68 flange portion, 70 bolt, 75 rotation stopper member, 100 chamber, 102 installation base, 104 through hole, 106 bolt insertion hole, 108 convex portion, 210 ceramic heater, 220 Hollow ceramic shaft, 230 shaft inner peripheral groove, 240 mounting unit, 250 mounting member, 260 mounting member outer peripheral groove, 265 holding member, G gap, S1, S2 internal spaces, W wafer.

Claims

1. A shaft end attachment structure for attaching an end of a hollow ceramic shaft, which is integrated with a ceramic plate having a wafer mounting surface, to an installation base, comprising: a seal member disposed between the end surface of the hollow ceramic shaft and the mounting base; a female screw portion provided on an inner peripheral surface of the hollow ceramic shaft; a mounting member having a male screw portion that is screwed into the female screw portion, the mounting member attaching the hollow ceramic shaft to the mounting base in a pulling manner; A shaft end mounting structure comprising:

2. 2. The shaft end attachment structure according to claim 1, a rotation stopper member that prevents the hollow ceramic shaft from rotating axially relative to the mounting member; The inner peripheral surface of the hollow ceramic shaft and the outer peripheral surface of the mounting member have rotation stopper arrangement holes in which the rotation stopper member is arranged, at positions facing each other. Shaft end mounting structure.

3. a gap is provided between the inner peripheral surface of the hollow ceramic shaft and the outer peripheral surface of the mounting member on the installation table side, the gap being usable for removing the rotation stopper member; The shaft end attachment structure according to claim 2 .

4. The shaft end mounting structure according to any one of claims 1 to 3, wherein the thread diameter of the male thread portion is 35 mm or more and 65 mm or less, and the pitch of the male thread portion is 10% or more and 20% or less of the thread diameter.

5. The mounting member has a screw hole that opens toward the installation base, and a bolt that penetrates the back surface of the installation base is screwed into the screw hole to attract the hollow ceramic shaft to the installation base. The shaft end attachment structure according to any one of claims 1 to 3.

6. the end face of the hollow ceramic shaft has a sealing surface with a surface roughness Ra of 0.5 μm or less; The sealing member is disposed between the sealing surface and the installation base. The shaft end attachment structure according to any one of claims 1 to 3.

7. The female screw portion is provided within a range of 150 mm from the end face of the hollow ceramic shaft. The shaft end attachment structure according to any one of claims 1 to 3.

8. The thread diameter of the male screw portion of the mounting member is larger than the outer diameter of a portion of the male screw portion that is closer to the installation base. The shaft end attachment structure according to any one of claims 1 to 3.

9. The thread diameter of the male screw portion of the mounting member is equal to or smaller than the outer diameter of a portion of the male screw portion that is closer to the installation base. The shaft end attachment structure according to any one of claims 1 to 3.

10. The entire outer peripheral surface of the mounting member is a male thread portion. The shaft end attachment structure according to any one of claims 1 to 3.

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