Members for semiconductor manufacturing equipment

Abstract

The wafer mounting table 10 includes a ceramic plate 20 having a wafer mounting surface 20a on its upper surface, an electrostatic electrode 22 embedded in the ceramic plate 20, an electrode extraction portion 23 embedded in the ceramic plate 20 and provided downward from the electrostatic electrode 22, a terminal hole 24 provided so as to reach the electrode extraction portion 23 from the lower surface of the ceramic plate 20, a terminal 50 inserted into the terminal hole 24, and a conductive joint portion 55 provided between the terminal 50 and the electrode extraction portion 23 for joining the terminal 50 and the electrode extraction portion 23. The terminal hole 24 has a terminal hole reduced diameter surface 24a that reduces in diameter toward the hole bottom, and the terminal hole reduced diameter surface 24a is provided so as to intersect the side surface 23a of the electrode extraction portion 23.

Description

Technical Field

[0001] The present invention relates to a member for a semiconductor manufacturing apparatus.

Background Art

[0002] In semiconductor manufacturing apparatuses, members for semiconductor manufacturing apparatuses such as ceramic heaters for heating wafers and electrostatic chucks for adsorbing and holding wafers are employed. Patent Document 1 discloses a structure in which a power supply terminal is joined to an electrode embedded in a ceramic plate in this type of member for a semiconductor manufacturing apparatus. Specifically, an electrode extraction portion provided downward from the electrode together with the electrode is embedded in the ceramic plate, a terminal hole is provided so as to reach the electrode extraction portion from the lower surface of the ceramic plate, and a terminal is inserted into this terminal hole and joined to the electrode via the electrode extraction portion. The electrode extraction portion has a frustum shape, and the inclination angle of its side surface is 40° or less. The terminal hole is provided such that a flat bottom surface intersects the side surface of the electrode extraction portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the member for a semiconductor manufacturing apparatus of Patent Document 1, due to the thinning of the ceramic plate between the inclined side surface of the electrode extraction portion and the flat bottom surface of the terminal hole, this portion may crack or peel due to the load during processing or the thermal stress during use, and may be damaged.

[0005] The present invention has been made to solve the above-described problems, and has as its main object to suppress damage to members for semiconductor manufacturing apparatuses.

Means for Solving the Problems

[0006] [1] The member for a semiconductor manufacturing apparatus of the present invention includes a ceramic plate having a wafer placement surface on its upper surface, an electrode embedded in the ceramic plate, an electrode extraction portion embedded in the ceramic plate and provided downward from the electrode, a terminal hole provided so as to reach the electrode extraction portion from the lower surface of the ceramic plate, a terminal inserted into the terminal hole, a conductive joint portion provided between the terminal and the electrode extraction portion and joining the terminal and the electrode extraction portion, and is provided with the terminal hole has a terminal hole diameter-reducing surface that reduces in diameter toward the bottom of the terminal hole, and the terminal hole diameter-reducing surface is provided so as to intersect the side surface of the electrode extraction portion. That's what it is.

[0007] In this member for a semiconductor manufacturing apparatus, the terminal hole has a terminal hole diameter-reducing surface that reduces in diameter toward the bottom of the hole, and this terminal hole diameter-reducing surface is provided so as to intersect the side surface of the electrode extraction portion. Thereby, for example, compared to the case where the flat bottom surface of the terminal hole intersects the inclined side surface of the electrode extraction portion, the ceramic plate between the electrode extraction portion and the terminal hole can be made thicker by the amount of inclination of the terminal hole diameter-reducing surface. Therefore, the formation of a thin portion in the ceramic plate can be suppressed, and breakage of the member for a semiconductor manufacturing apparatus can be suppressed.

[0008] In addition, in this specification, the present invention may be described using up and down, left and right, front and back, etc. However, up and down, left and right, front and back are merely relative positional relationships. Therefore, when the orientation of the member for a semiconductor manufacturing apparatus is changed, up and down may become left and right or left and right may become up and down. Even in such cases, it is included in the technical scope of the present invention.

[0009] [2] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus described in [1] above), the side surface of the electrode extraction portion may be reduced in diameter toward the lower side. By doing so, it is possible to reduce the volume of the electrode extraction portion while securing the contact area between the electrode and the electrode extraction portion. When the volume of the electrode extraction portion is reduced, cracking and peeling of the ceramic plate due to the difference in thermal expansion between the ceramic plate and the electrode extraction portion can be suppressed.

[0010] [3] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus described in [1] or [2] above), at the intersection of the terminal hole diameter-reduced surface and the side surface of the electrode extraction portion, the angle formed by the virtual plane parallel to the electrode and the terminal hole diameter-reduced surface may be 20° or more and 75° or less. If this angle is 20° or more, it is difficult to form a thin portion in the ceramic plate, so cracking and peeling of the ceramic plate can be further suppressed. If this angle is 75° or less, for example, even if the bottom of the terminal hole is made smaller in diameter according to the size of the electrode extraction portion, the diameter of the terminal hole can be made relatively large. Thereby, the terminal diameter of the terminal inserted into the terminal hole can be increased, so good electrical conductivity can be ensured.

[0011] [4] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus described in any one of [1] to [3] above), the intersection angle between the terminal hole diameter-reduced surface and the side surface of the electrode extraction portion may be 40° or more and 120° or less. If this intersection angle is 40° or more, it is difficult to form a thin portion in the ceramic plate, so cracking and peeling of the ceramic plate can be further suppressed. If this intersection angle is 120° or less, for example, even if the bottom of the terminal hole is made smaller in diameter according to the size of the electrode extraction portion, the diameter of the terminal hole can be made relatively large. Thereby, the terminal diameter of the terminal inserted into the terminal hole can be increased, so good electrical conductivity can be ensured.

[0012] [5] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus according to any one of [1] to [4] above), the side surface of the electrode extraction portion is reduced in diameter toward the lower side, and the inclination angle of the side surface of the electrode extraction portion may be smaller than the intersection angle between the reduced-diameter surface of the terminal hole and the side surface of the electrode extraction portion. The smaller the inclination angle of the side surface of the electrode extraction portion, the smaller the volume of the electrode extraction portion can be, so that cracking and peeling of the ceramic plate due to the difference in thermal expansion between the ceramic plate and the electrode extraction portion can be further suppressed.

[0013] [6] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus according to any one of [1] to [5] above), the reduced-diameter surface of the terminal hole may enter the electrode extraction portion. By doing so, it is easy to secure the contact area between the electrode extraction portion and the conductive joint portion, so that the electrical conductivity can be enhanced.

[0014] [7] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus according to any one of [1] to [6] above), the reduced-diameter surface of the terminal hole may be a C surface or an R surface provided between the bottom surface and the side surface of the terminal hole.

[0015] [8] In the member for a semiconductor manufacturing apparatus of the present invention (the member for a semiconductor manufacturing apparatus according to any one of [1] to [7] above), the reduced-diameter surface of the terminal hole is a C surface provided between the bottom surface and the side surface of the terminal hole, the terminal has a reduced-diameter surface that is reduced in diameter toward the tip of the terminal, the reduced-diameter surface of the terminal is a C surface provided between the tip surface and the side surface of the terminal, and the reduced-diameter surface of the terminal hole and the reduced-diameter surface of the terminal may be joined at the conductive joint portion. By doing so, since the C-surface-shaped reduced-diameter surface of the terminal hole can receive the C-surface-shaped reduced-diameter surface of the terminal and join the two, the concentration of the pressing force from the terminal on the bottom surface of the terminal hole is suppressed, and cracking and peeling of the ceramic plate around the bottom surface of the terminal hole can be suppressed. From the viewpoint of evenly dispersing the pressing force from the terminal, it is preferable that the size of the C surface of the reduced-diameter surface of the terminal hole is equal to the size of the C surface of the reduced-diameter surface of the terminal, and it is preferable that the inclination of the C surface of the reduced-diameter surface of the terminal hole is equal to the inclination of the C surface of the reduced-diameter surface of the terminal.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0017] FIG. 1 is a cross-sectional view showing the schematic configuration of the wafer stage 10 of the present embodiment (a cross-sectional view when the wafer stage 10 is cut along a plane including the central axis of the wafer stage 10), and FIG. 2 is a partial enlarged view of FIG. 1 (an enlarged view within the frame indicated by the two-dot chain line). In the following description, up and down, left and right, and front and back may be used, but up and down, left and right, and front and back are only relative positional relationships.

[0018] The wafer stage 10 is an example of a member for a semiconductor manufacturing apparatus used for processing the wafer W. As shown in FIG. 1, the wafer stage 10 includes a ceramic plate 20, a cooling plate 30, a bonding layer 40, and a terminal 50.

[0019] The ceramic plate 20 is a disc-shaped member having a wafer placement surface 20a on its upper surface. The ceramic plate 20 is formed of a ceramic-containing material. The ceramic-containing material is a material mainly composed of ceramic, and may contain, in addition to the ceramic, components derived from a sintering aid (such as rare earth elements, etc.) and inevitable components. The main component means that the proportion in the whole is 50% by mass or more. Examples of the ceramic include alumina and aluminum nitride.

[0020] An electrostatic electrode 22 is embedded in the ceramic plate 20. The electrostatic electrode 22 is formed of a material containing a metal such as W, Mo, WC, or MoC. As the metal used for the electrostatic electrode 22, those having a coefficient of thermal expansion close to that of the ceramic plate 20 are preferable. In order to make the coefficient of thermal expansion of the electrostatic electrode 22 close to that of the ceramic plate 20, the ceramic contained in the ceramic plate 20 may be contained in the electrostatic electrode 22. The electrostatic electrode 22 is a disc-shaped or mesh-shaped unipolar electrostatic electrode. The layer above the electrostatic electrode 22 in the ceramic plate 20 functions as a dielectric layer. A DC power supply 62 for electrostatic adsorption is connected to the electrostatic electrode 22 via a terminal 50.

[0021] The cooling plate 30 is a disc-shaped member having a refrigerant flow path 32 through which refrigerant can circulate inside. The refrigerant flow path 32 is formed in one stroke from one end to the other end so as to cover the entire surface of the ceramic plate 20 in a plan view. One end and the other end of the refrigerant flow path 32 are connected to a refrigerant circulation pump (not shown) having a function of adjusting the temperature of the refrigerant. The cooling plate 30 is made of, for example, a conductive material containing metal. Examples of the conductive material include composite materials and metals. Examples of the composite material include metal matrix composites (also referred to as metal matrix composites (MMC)). Examples of MMC include materials containing Si, SiC, and Ti, and materials obtained by impregnating a SiC porous body with Al and / or Si. A material containing Si, SiC, and Ti is referred to as SiSiCTi, a material obtained by impregnating a SiC porous body with Al is referred to as AlSiC, and a material obtained by impregnating a SiC porous body with Si is referred to as SiSiC. Examples of the metal include Al, Ti, Mo, or alloys thereof. As the conductive material used for the cooling plate 30, those having a coefficient of thermal expansion close to that of the ceramic plate 20 are preferable.

[0022] The bonding layer 40 bonds the lower surface of the ceramic plate 20 and the upper surface of the cooling plate 30. The bonding layer 40 may be, for example, a metal bonding layer formed of solder or a metal brazing material. The metal bonding layer may be formed, for example, by TCB (Thermal compression bonding). TCB refers to a known method in which a metal bonding material is sandwiched between two members to be bonded, and the two members are pressure-bonded in a state of being heated to a temperature below the solidus temperature of the metal bonding material. As the bonding layer 40, an organic adhesive layer may be employed instead of the metal bonding layer.

[0023] The terminal 50 is a metallic member that supplies power to the electrostatic electrode 22. The terminal 50 is, for example, a metal rod. The metal used for the terminal 50 is, for example, W, Mo, Ni, etc., and it is preferable that the thermal expansion coefficient of the metal is close to the thermal expansion coefficient of the ceramic plate 20. The terminal 50 is inserted into a terminal hole 24 provided in the ceramic plate 20 through a cooling plate through-hole 34 that vertically penetrates the cooling plate 30 and a bonding layer through-hole 44 that vertically penetrates the bonding layer 40 from the lower surface side of the cooling plate 30. The terminal 50 is electrically connected to the electrostatic electrode 22.

[0024] The joining structure between the terminal 50 and the electrostatic electrode 22 will be described with reference to FIG. 2. The terminal 50 passes through the inside of an insulating tube 36 disposed in the cooling plate through-hole 34 and the bonding layer through-hole 44 and is inserted into the terminal hole 24 playfully. The terminal 50 is electrically connected to an electrode extraction portion 23 added to the electrostatic electrode 22 via a conductive joint portion 55. The conductive joint portion 55 may be a metal joint layer formed of solder or a metal brazing material.

[0025] The electrode extraction portion 23 is a disk-shaped member embedded in the ceramic plate 20 and provided downward from the electrostatic electrode 22. The electrode extraction portion 23 is formed of a material containing a metal such as, for example, W, Mo, WC, MoC. As the metal used for the electrode extraction portion 23, it is preferable that the thermal expansion coefficient is close to the thermal expansion coefficient of the ceramic plate 20. In order to make the thermal expansion coefficient of the electrode extraction portion 23 close to the thermal expansion coefficient of the ceramic plate 20, the ceramic contained in the ceramic plate 20 may be contained in the electrode extraction portion 23. The electrode extraction portion 23 may be formed of a material having the same composition as the electrostatic electrode 22. The electrode extraction portion 23 has a frustum shape, and its side surface 23a tapers downward. The electrode extraction portion 23 is exposed on the bottom surface 24b of the terminal hole 24.

[0026] The terminal hole 24 is a cylindrical hole provided so as to reach the electrode extraction portion 23 from the lower surface of the ceramic plate 20. The terminal hole 24 has a terminal hole diameter-reducing surface 24a that reduces in diameter toward the hole bottom. The terminal hole diameter-reducing surface 24a is provided between the bottom surface 24b and the side surface 24c of the terminal hole 24, and is a C surface (tapered surface) in the shape of chamfering the edge at the boundary between the bottom surface 24b and the side surface 24c of the terminal hole 24.

[0027] The terminal hole diameter-reducing surface 24a intersects with the side surface 23a of the electrode extraction portion 23 at the intersection portion 25. Therefore, breakage of the wafer mounting table 10 can be suppressed. This point will be described below. FIG. 8 is a partially enlarged view of the wafer mounting table 110 of a comparative form (the form of the prior art disclosed in Patent Document 1). In the wafer mounting table 110, the terminal 150 is electrically connected to the electrode extraction portion 123 embedded in the ceramic plate 120 together with the electrostatic electrode 122 via the conductive bonding portion 155. The electrode extraction portion 123 has a frustum shape, and its side surface 123a reduces in diameter downward. The electrode extraction portion 123 is exposed on the bottom surface 124b of the terminal hole 124. The terminal hole 124 is a cylindrical hole provided so as to reach the electrode extraction portion 123 from the lower surface of the ceramic plate 120. In this wafer mounting table 110, the bottom surface 124b of the terminal hole 124 is flat, and the bottom surface 124b of this terminal hole 124 intersects with the side surface 123a of the electrode extraction portion 123. Therefore, the ceramic plate 120 between the inclined side surface 123a of the electrode extraction portion 123 and the flat bottom surface 124b of the terminal hole 124 becomes thin. And the said part may be damaged by cracking or peeling due to loads such as drilling of the terminal hole 124 and bonding between the electrostatic electrode 122 and the terminal 150. On the other hand, in the wafer mounting table 10 of the present embodiment, the ceramic plate 20 between the electrode extraction portion 23 and the terminal hole 24 can be thickened by the amount of inclination of the terminal hole diameter-reducing surface 24a, for example, by the angle α described later. Therefore, the formation of a thin portion in the ceramic plate 20 can be suppressed, and breakage of the wafer mounting table 10 can be suppressed.

[0028] At the intersection 25 between the reduced-diameter surface 24a of the terminal hole and the side surface 23a of the electrode extraction portion 23, the angle α formed between the virtual plane P parallel to the electrostatic electrode 22 and the reduced-diameter surface 24a of the terminal hole is preferably, for example, 20° or more and 75° or less. Further, the intersection angle β between the reduced-diameter surface 24a of the terminal hole and the side surface 23a of the electrode extraction portion 23 is preferably, for example, 40° or more and 120° or less. Also, the inclination angle γ of the side surface 23a of the electrode extraction portion 23 is preferably smaller than the intersection angle β between the reduced-diameter surface 24a of the terminal hole and the side surface 23a of the electrode extraction portion 23. When the reduced-diameter surface 24a of the terminal hole is a curved surface, the angle α and the angle β may be obtained using the tangent line of the reduced-diameter surface 24a of the terminal hole at the intersection 25. When the side surface 23a of the electrode extraction portion 23 is a curved surface, the angle α and the angle β may be obtained using the tangent line of the side surface 23a of the electrode extraction portion 23 at the intersection 25. When the side surface 23a of the electrode extraction portion 23 is a curved surface, the angle γ may be obtained using the tangent line of the side surface 23a of the electrode extraction portion 23 at the location where the lower surface of the electrostatic electrode 22 intersects the side surface 23a of the electrode extraction portion 23.

[0029] The reduced-diameter surface 24a of the terminal hole is provided so as to enter the electrode extraction portion 23. Therefore, not only the bottom surface 24b of the terminal hole 24 but also a part of the reduced-diameter surface 24a of the terminal hole exposes the electrode extraction portion 23.

[0030] The terminal 50 has a reduced-diameter surface 50a that tapers toward the tip. The reduced-diameter surface 50a is provided between the tip surface 50b and the side surface 50c of the terminal 50, and is a C surface (tapered surface) with a chamfered edge at the boundary between the tip surface 50b and the side surface 50c of the terminal 50. The conductive joint 55 is disposed not only between the bottom surface 24b of the terminal hole 24 and the tip surface 50b of the terminal 50 but also between the reduced-diameter surface 24a of the terminal hole and the reduced-diameter surface 50a of the terminal, and the reduced-diameter surface 24a of the terminal hole and the reduced-diameter surface 50a of the terminal are joined by the conductive joint 55. Thereby, the terminal 50 is joined to the electrode extraction portion 23 exposed on the bottom surface 24b and the reduced-diameter surface 24a of the terminal hole, and is also joined to the ceramic plate 20.

[0031] Next, an example of using the wafer stage 10 will be described. First, the wafer stage 10 is installed in a vacuum chamber (not shown), and the wafer W is placed on the wafer placement surface 20a of the wafer stage 10. Then, a voltage is applied to the electrostatic electrode 22 from the DC power supply 62 via the terminal 50. Then, the wafer W is adsorbed and fixed to the wafer placement surface 20a. Then, the inside of the vacuum chamber is set to a vacuum atmosphere or a reduced pressure atmosphere, and the wafer W is processed in the vacuum chamber. For example, when processing the wafer W with plasma, an upper electrode equipped with a shower head is arranged on the ceiling inside the vacuum chamber, and a reaction gas is supplied from the shower head to the space between the wafer W and the upper electrode while applying a high-frequency voltage between the upper electrode and the cooling plate 30 to generate plasma. After the processing of the wafer W is completed, the application of the voltage to the electrostatic electrode 22 is released. Then, the adsorption and fixation of the wafer W to the wafer placement surface 20a are released. Note that the refrigerant is flowed through the refrigerant flow path 32 when it is necessary to lower the temperature of the wafer W.

[0032] Next, among the manufacturing methods of the wafer stage 10, the step of joining the terminal 50 and the electrostatic electrode 22 in particular will be described with reference to FIG. 3. FIG. 3 is an explanatory diagram of this step.

[0033] First, a ceramic plate 20 in which the electrostatic electrode 22 and the disk member 23z added to the electrostatic electrode 22 are embedded is produced (FIG. 3A). The disk member 23z is a member that will become the electrode extraction portion 23 by later drilling. The disk member 23z is a spherical segment shape or a spherical frustum shape member whose diameter decreases as it moves away from the electrostatic electrode 22. Such a ceramic plate 20 can be produced, for example, as follows. First, two disk-shaped compacts of ceramic powder are produced. Subsequently, a printed electrode having the same shape as the electrostatic electrode 22 is printed on the upper surface of the first disk-shaped compact so as to be concentric with the disk-shaped compact. A printed electrode having the same shape as the disk member 23z is printed at a predetermined position on the upper surface of this printed electrode. Then, the second disk-shaped compact is laminated on the printed electrode surface of the first disk-shaped compact to form a laminate. This laminate is hot press fired to obtain the ceramic plate 20. Note that in FIGS. 3A to 3D, the surface that will become the wafer placement surface 20a of the ceramic plate 20 is oriented downward.

[0034] Subsequently, a terminal hole 24 reaching the electrode extraction portion 23 is formed from one surface of the ceramic plate 20 (FIG. 3B). The terminal hole 24 shall have a reduced-diameter surface 24a of the terminal hole between the bottom surface 24b and the side surface 24c. Then, the terminal hole 24 is formed such that the bottom surface 24b of the terminal hole 24 and a part of the reduced-diameter surface 24a of the terminal hole enter the disk member 23z, and the electrode extraction portion 23 is exposed on the bottom surface 24b of the terminal hole 24 and a part of the reduced-diameter surface 24a of the terminal hole. The terminal hole 24 can be formed by a known hole-making process such as drilling or laser processing.

[0035] Subsequently, a conductive bonding material 55z is disposed at the bottom of the terminal hole 24 (FIG. 3C). The bonding material 55z will later become the conductive bonding portion 55, and may be, for example, a metal sheet formed of solder or a metal brazing material.

[0036] Subsequently, the terminal 50 is disposed on the bonding material 55z, and the bonding material 55z is sandwiched between the terminal hole 24 and the terminal 50. In this state, when processed at a temperature equal to or higher than the melting point of the bonding material 55z, the bonding material 55z melts and spreads wetly between the terminal hole 24 and the terminal 50. When the bonding material 55z solidifies in this state, the electrode extraction portion 23 exposed in the terminal hole 24 and the terminal 50 are joined by the conductive bonding portion 55 (FIG. 3D). Thereby, the terminal 50 and the electrostatic electrode 22 are electrically connected.

[0037] In the wafer mounting stage 10 described above, the terminal hole 24 has a reduced-diameter surface 24a of the terminal hole that tapers toward the bottom of the hole, and the reduced-diameter surface 24a of the terminal hole is provided so as to intersect the side surface 23a of the electrode extraction portion 23. Therefore, it is possible to suppress the formation of a thin portion in the ceramic plate 20 and suppress damage to the wafer mounting stage 10.

[0038] Further, the side surface 23a of the electrode extraction portion 23 is reduced in diameter toward the lower side. Therefore, while securing the contact area between the electrostatic electrode 22 and the electrode extraction portion 23, the volume of the electrode extraction portion 23 can be reduced. Reducing the volume of the electrode extraction portion 23 can suppress cracking and peeling of the ceramic plate 20 due to the difference in thermal expansion between the ceramic plate 20 and the electrode extraction portion 23.

[0039] Furthermore, at the intersection 25 between the terminal hole diameter-reduced surface 24a and the side surface 23a of the electrode extraction portion 23, the angle α formed between the virtual plane P parallel to the electrostatic electrode 22 and the terminal hole diameter-reduced surface 24a may be 20° or more and 75° or less. If this angle α is 20° or more, it is difficult to form a thin portion in the ceramic plate 20, so cracking and peeling of the ceramic plate 20 can be further suppressed. If this angle α is 75° or less, for example, even if the bottom of the terminal hole 24 is made smaller in diameter according to the size of the electrode extraction portion 23, the diameter of the terminal hole 24 can be made relatively large. Thereby, since the terminal diameter of the terminal 50 inserted into the terminal hole 24 can be increased, good electrical conductivity can be ensured.

[0040] Moreover, the intersection angle β between the terminal hole diameter-reduced surface 24a and the side surface 23a of the electrode extraction portion 23 may be 40° or more and 120° or less. If this intersection angle β is 40° or more, it is difficult to form a thin portion in the ceramic plate 20, so cracking and peeling of the ceramic plate 20 can be further suppressed. If this intersection angle is 120° or less, for example, even if the bottom of the terminal hole 24 is made smaller in diameter according to the size of the electrode extraction portion 23, the diameter of the terminal hole 24 can be made relatively large. Thereby, since the terminal diameter of the terminal 50 inserted into the terminal hole 24 can be increased, good electrical conductivity can be ensured.

[0041] Also, the inclination angle γ of the side surface 23a of the electrode extraction portion 23 may be smaller than the intersection angle β between the terminal hole diameter-reduced surface 24a and the side surface 23a of the electrode extraction portion 23. The smaller the inclination angle γ of the side surface 23a of the electrode extraction portion 23, the smaller the volume of the electrode extraction portion 23 can be, so cracking and peeling of the ceramic plate 20 due to the difference in thermal expansion between the ceramic plate 20 and the electrode extraction portion 23 can be further suppressed.

[0042] Furthermore, the reduced-diameter surface of the terminal hole 24a extends into the electrode extraction portion 23. Therefore, it is easy to secure the contact area between the electrode extraction portion 23 and the conductive joint portion 55, and the electrical conductivity can be enhanced.

[0043] Furthermore, the reduced-diameter surface 24a of the terminal hole is a C surface provided between the bottom surface 24b and the side surface 24c of the terminal hole 24. The terminal 50 has a reduced-diameter surface 50a that tapers toward the tip of the terminal 50. The reduced-diameter surface 50a is a C surface provided between the tip surface 50b and the side surface 50c of the terminal 50. The reduced-diameter surface 24a of the terminal hole and the reduced-diameter surface 50a of the terminal are joined by the conductive joint portion 55. Thereby, since the C-surface-shaped reduced-diameter surface 24a of the terminal hole can receive the C-surface-shaped reduced-diameter surface 50a of the terminal and join the two, it is possible to suppress the concentration of the pressing force from the terminal 50 on the bottom surface 24b of the terminal hole 24, and it is possible to suppress cracking and peeling of the ceramic plate 20 around the bottom surface 24b of the terminal hole 24. From the viewpoint of evenly dispersing the pressing force from the terminal 50, it is preferable that the size of the C surface of the reduced-diameter surface 24a of the terminal hole is equal to the size of the C surface of the reduced-diameter surface 50a of the terminal, and it is also preferable that the inclination of the C surface of the reduced-diameter surface 24a of the terminal hole is equal to the inclination of the C surface of the reduced-diameter surface 50a of the terminal. The inclination of the C surface of the reduced-diameter surface 24a and the reduced-diameter surface 50a of the terminal may each be, for example, 30° or more and 60° or less. The size of the C surface of the reduced-diameter surface 24a and the reduced-diameter surface 50a of the terminal may each be, for example, 0.3 mm or more and 2.5 mm or less. Note that the diameter of the bottom surface 24b of the terminal hole 24 may be smaller than the diameter of the side surface 50c of the terminal 50, and may also be smaller than the diameter of the bottom surface 50b of the terminal 50.

[0044] Note that the present invention is not limited to the above-described embodiments at all, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

[0045] In the above-described embodiment, the reduced-diameter surface 24a of the terminal hole is a chamfered surface C formed by chamfering the edge at the boundary between the bottom surface 24b and the side surface 24c of the terminal hole 24, but it is not limited to this. For example, like the wafer mounting table 10B of another example shown in FIG. 4, the reduced-diameter surface 24a of the terminal hole may be a rounded surface R formed by rounding the edge at the boundary between the bottom surface 24b and the side surface 24c of the terminal hole 24. Further, the bottom surface 24b of the terminal hole 24 may be a rounded surface R, and the rounded surface-shaped bottom surface 24b may also serve as the reduced-diameter surface 24a of the terminal hole. The radius of curvature of the rounded surface R of the reduced-diameter surface 24a may be, for example, 0.3 mm or more and 2.5 mm or less. In FIG. 4, the same components as those in the above-described embodiment are denoted by the same reference numerals.

[0046] In the above-described embodiment and another example, the electrode extraction portion 23 has a frustum shape, but it is not limited to this. For example, like the wafer mounting table 10C of another example shown in FIG. 5, the electrode extraction portion 23 may have a truncated cone shape. In that case, in the step of joining the terminal 50 and the electrostatic electrode 22, a member having a conical shape or a truncated cone shape may be used as the disc member 23z. Further, for example, like the wafer mounting table 10D of another example shown in FIG. 6, the electrode extraction portion 23 may have a cylindrical shape. In that case, in the step of joining the terminal 50 and the electrostatic electrode 22, a cylindrical member may be used as the disc member 23z. In FIGS. 5 and 6, the same components as those in the above-described embodiment are denoted by the same reference numerals.

[0047] In the above-described embodiment and another example, the reduced-diameter surface 24a of the terminal hole is provided so as to enter the electrode extraction portion 23, but it is not limited to this. For example, like the wafer mounting table 10E of another example shown in FIG. 7, the reduced-diameter surface 24a of the terminal hole may be provided so as to abut against the side surface 23a of the electrode extraction portion 23 without entering the electrode extraction portion 23. In FIG. 7, the same components as those in the above-described embodiment are denoted by the same reference numerals.

[0048] In the above-described embodiments and alternative examples, the terminal reduced-diameter surface 50a is a chamfered surface C having a shape obtained by chamfering the edge at the boundary between the tip surface 50b and the side surface 50c of the terminal 50. However, the present invention is not limited to this. For example, the terminal reduced-diameter surface 50a may be a rounded surface R having a shape obtained by rounding the edge at the boundary between the tip surface 50b and the side surface 50c of the terminal 50. Further, the tip surface 50b of the terminal 50 may be a rounded surface, and the rounded tip surface 50b may also serve as the terminal reduced-diameter surface 50a. The radius of curvature of the rounded surface of the terminal reduced-diameter surface 50a may be, for example, 0.3 mm or more and 2.5 mm or less. Further, the terminal 50 may not have the terminal reduced-diameter surface 50a, and the tip surface 50b and the side surface 50c may intersect at a right angle.

[0049] In the above-described embodiments and alternative examples, the conductive joint 55 only needs to be able to join the terminal 50 and the electrode extraction portion 23 to electrically connect the two. For example, it may be disposed only between the electrode extraction portion 23 exposed on the bottom surface 24b of the terminal hole 24 and the tip surface 50b of the terminal 50, or may be disposed only between the electrode extraction portion 23 exposed on the terminal hole reduced-diameter surface 24a and the terminal reduced-diameter surface 50a.

[0050] In the above-described embodiments and alternative examples, a metal rod is exemplified as the terminal 50. However, the present invention is not particularly limited thereto, and for example, a metal cable may be used.

[0051] In the above-described embodiments and alternative examples, at least one of a heater electrode and an RF electrode (electrode for generating plasma) may be embedded in the ceramic plate 20 of the wafer mounting table 10 instead of or in addition to the electrostatic electrode 22. In that case, the joining structure between the heater electrode and the terminal for the heater electrode and the joining structure between the RF electrode and the terminal for the RF electrode may be the same as the joining structure between the electrostatic electrode 22 and the terminal 50 described above.

Industrial Applicability

[0052] The present invention can be used in a semiconductor manufacturing apparatus used for processing a wafer.

Explanation of Reference Numerals

[0053] 10, 10B, 10C, 10D, 10E wafer mounting table, 20 ceramic plate, 20a wafer mounting surface, 22 electrostatic electrode, 23 electrode extraction part, 23a side surface, 23z disc member, 24 terminal hole, 24a reduced diameter surface of terminal hole, 24b bottom surface, 24c side surface, 25 boundary part, 30 cooling plate, 32 refrigerant flow path, 34 through hole in cooling plate 、3 6 insulating tube, 40 bonding layer, 44 through hole in bonding layer, 50 terminal, 50a reduced diameter surface of terminal, 50b tip surface, 50c side surface, 55 conductive bonding part, 55z bonding material, 62 DC power supply, 110 wafer mounting table, 120 ceramic plate, 120a wafer mounting surface, 122 electrostatic electrode, 123 electrode extraction part, 123a side surface, 124 terminal hole, 124b bottom surface, 150 terminal, 150b tip surface, 155 conductive bonding part.

Claims

1. A ceramic plate having a wafer placement surface on the upper surface, an electrode embedded in the ceramic plate, an electrode extraction portion embedded in the ceramic plate and provided downward from the electrode, a terminal hole provided so as to reach the electrode extraction portion from the lower surface of the ceramic plate, a terminal inserted into the terminal hole, a conductive joint portion provided between the terminal and the electrode extraction portion for joining the terminal and the electrode extraction portion, comprising: the terminal hole has a reduced diameter surface of the terminal hole that reduces in diameter toward the bottom of the terminal hole, and the reduced diameter surface of the terminal hole is provided so as to intersect the side surface of the electrode extraction portion, a member for a semiconductor manufacturing apparatus.

2. The side surface of the electrode extraction portion is reduced in diameter toward the lower side, The member for a semiconductor manufacturing apparatus according to Claim 1.

3. At the intersection of the reduced diameter surface of the terminal hole and the side surface of the electrode extraction portion, the angle formed by the virtual surface parallel to the electrode and the reduced diameter surface of the terminal hole is 20° or more and 75° or less, The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

4. The intersection angle between the reduced diameter surface of the terminal hole and the side surface of the electrode extraction portion is 40° or more and 120° or less, The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

5. The side surface of the electrode extraction portion is reduced in diameter toward the lower side, and the inclination angle of the side surface of the electrode extraction portion is smaller than the intersection angle between the reduced diameter surface of the terminal hole and the side surface of the electrode extraction portion, The member for a semiconductor manufacturing apparatus according to Claim 4.

6. The reduced diameter surface of the terminal hole extends into the electrode extraction portion, The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

7. The reduced diameter surface of the terminal hole is a C surface or an R surface provided between the bottom surface and the side surface of the terminal hole. The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

8. The reduced diameter surface of the terminal hole is a C surface provided between the bottom surface and the side surface of the terminal hole, the terminal has a reduced diameter surface of the terminal that reduces in diameter toward the tip of the terminal, and the reduced diameter surface of the terminal is a C surface provided between the tip surface and the side surface of the terminal, the reduced diameter surface of the terminal hole and the reduced diameter surface of the terminal are joined at the conductive joint portion, The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

9. The electrode extraction portion is in the shape of a truncated sphere, a truncated cone, or a cylinder, The member for a semiconductor manufacturing apparatus according to Claim 1 or 2.

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