Member for semiconductor manufacturing apparatus

Abstract

Provided is a member for a semiconductor manufacturing apparatus in which a discharge suppression technique different from conventional ones is adopted. The member for a semiconductor manufacturing apparatus comprises: a ceramic substrate having an upper surface for mounting a wafer, and a lower surface; a plug placement hole penetrating the ceramic substrate in a vertical direction; and a plug embedded in the plug placement hole. The plug is composed of a dense body and has an upper end surface exposed on the upper surface side, a lower end surface exposed on the lower surface side, and a gas flow path extending from an upper-end opening provided in the upper end surface, through the inside of the dense body, to a lower-end opening provided in the lower end surface. The maximum height D1 in the vertical direction from the upper-end opening to the surface of the gas flow path, and the maximum height D2 in the vertical direction from the lower-end opening to the surface of the gas flow path satisfy the relationship D1 < D2.

Description

Semiconductor manufacturing equipment components

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

[0002] Conventionally, semiconductor manufacturing equipment components have been known that are used for holding wafers, controlling their temperature, transporting them, etc. These types of semiconductor manufacturing equipment components are also called wafer mounting tables, electrostatic chucks, susceptors, etc., and generally have the function of applying electrostatic attraction power to a built-in electrode to attract the wafer by electrostatic force, and some are also known to have the function of controlling the wafer temperature by flowing gas between the wafer mounting surface and the wafer to be attracted.

[0003] A known component for semiconductor manufacturing equipment includes a ceramic substrate having an upper surface for placing a wafer, a gas passage that passes through the ceramic substrate in the vertical direction, and a conductive base plate bonded to the lower surface of the ceramic substrate. During wafer processing, a cooling gas such as helium gas is introduced to the backside of the wafer through the gas passage.

[0004] In such semiconductor manufacturing equipment components, a large potential difference may occur between the wafer and the base plate, which can lead to discharge (dielectric breakdown) between the wafer and the base plate through the gas passage. For this reason, various techniques for placing a plug in the gas passage have been investigated to suppress discharge. The plug is often made of a porous material. Without the plug, for example, when an RF voltage is applied, ionizing gas molecules, resulting in electrons that accelerate and collide with other gas molecules, resulting in a glow discharge and eventually an arc discharge. However, with the plug, the electrons strike the plug before colliding with other gas molecules, suppressing discharge.

[0005] Patent Document 1 proposes a plug having a gas flow path portion that bends and penetrates a dense main body portion in the thickness direction, and also proposes making at least a partial section of the entire length of the gas flow path portion insulating and porous.

[0006] Patent Document 2 discloses an electrostatic chuck comprising: a ceramic dielectric substrate having a first main surface on which an object to be attracted is placed and a second main surface opposite the first main surface; a base plate supporting the ceramic dielectric substrate and having a gas inlet passage; and a first porous portion provided between the base plate and the first main surface of the ceramic dielectric substrate and at a position facing the gas inlet passage, wherein the ceramic dielectric substrate has a first hole portion located between the first main surface and the first porous portion, and the first porous portion has a porous portion having a plurality of holes and a first dense portion that is denser than the porous portion, and when projected onto a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate, the first dense portion overlaps with the first hole portion, but the porous portion does not overlap with the first hole portion.

[0007] Patent Document 3 describes an electrostatic chuck including: a ceramic dielectric substrate having a first main surface on which an object to be attracted is placed and a second main surface opposite the first main surface; a base plate supporting the ceramic dielectric substrate and having a gas inlet passage; and a first porous portion provided between the base plate and the first main surface of the ceramic dielectric substrate and facing the gas inlet passage, wherein the first porous portion has a plurality of sparse portions having a plurality of holes and a dense portion having a density higher than a density of the sparse portions, each of the plurality of sparse portions extending in a first direction from the base plate toward the ceramic dielectric substrate, the dense portion being located between the plurality of sparse portions, the sparse portion having the holes and a wall portion provided between the holes, and a minimum value of a dimension of the wall portion being smaller than a minimum value of a dimension of the dense portion in a second direction substantially perpendicular to the first direction.

[0008] Patent Document 4 describes an invention aimed at providing a holding device capable of controlling the temperature of an object with high accuracy while reducing the occurrence of abnormal discharge. Specifically, the holding device described includes a ceramic substrate having a first surface for holding an object and a second surface opposite the first surface, a base member disposed on the second surface side of the ceramic substrate, the base member having a third surface opposite the ceramic substrate, and a bonding material disposed between the ceramic substrate and the base member, wherein (1) the ceramic substrate and the base member are formed with a flow path that allows a fluid to move between an outlet hole provided in the first surface and an inlet hole provided in the third surface, or (2) the ceramic substrate is formed with a flow path that allows a fluid to move between an outlet hole provided in the first surface and an inlet hole provided in the second surface, the flow path having a porous ceramic region, the porous ceramic region including a sparse region and a dense region having a lower porosity than the sparse region and disposed closer to the first surface than the sparse region.

[0009] In Patent Document 5, a wafer mounting table is provided with an insulating first porous portion disposed within a through-hole in a ceramic plate, and an insulating second porous portion fitted in a recess provided on the ceramic plate side of a base plate so as to face the first porous portion. Gas supplied to a gas inlet passage passes through the second and first porous portions and flows into the space between the wafer mounting surface and the wafer, where it is used to cool the object. The publication describes that the presence of the first and second porous portions ensures a gas flow rate from the gas inlet passage to the wafer mounting surface while suppressing the occurrence of discharge (arc discharge) caused by plasma during wafer processing.

[0010] JP 2022-119338 A JP 2022-31333 A JP 2019-165194 A JP 2022-176701 A JP 2020-72262 A

[0011] As described above, in order to suppress discharges occurring between the wafer and the baseplate in semiconductor manufacturing equipment components, various technologies have been proposed to improve the structure near the plugs located in the gas passages that penetrate the ceramic substrate in the vertical direction. However, discharges are more likely to occur during wafer processing, such as deep etching, which uses high-power plasma. Therefore, more advanced discharge prevention measures are required.

[0012] Therefore, it is desirable to develop a new discharge suppression technology. By combining such a new discharge suppression technology with a conventional discharge suppression technology, an even greater discharge suppression effect can be expected. Therefore, in one embodiment, an object of the present invention is to provide a semiconductor manufacturing equipment member that employs a discharge suppression technology different from conventional ones.

[0013] The present inventors conducted extensive research to solve the above problems and have created the present invention, as exemplified below. [Aspect 1] A semiconductor manufacturing equipment component comprising a ceramic substrate having upper and lower surfaces for mounting a wafer, a plug placement hole vertically penetrating the ceramic substrate, and a plug embedded in the plug placement hole, wherein the plug is made of a dense body and has an upper end face exposed on the upper surface, a lower end face exposed on the lower surface, and a gas flow path extending from an upper end opening provided in the upper end face to a lower end opening provided in the lower end face, penetrating the interior of the dense body, and wherein a maximum height D1 in the vertical direction from the upper end opening to the surface of the gas flow path and a maximum height D2 in the vertical direction from the lower end opening to the surface of the gas flow path satisfy the relationship D1 < D2. [Aspect 2] The semiconductor manufacturing equipment component according to Aspect 1, wherein the relationship 0.1 ≦ D1 / D2 ≦ 0.9 is satisfied. [Aspect 3] The semiconductor manufacturing equipment member according to Aspect 1 or 2, wherein the maximum height D1 is 10 to 300 μm. [Aspect 4] The semiconductor manufacturing equipment member according to any of Aspects 1 to 3, wherein the maximum height D2 is 50 to 500 μm. [Aspect 5] The semiconductor manufacturing equipment member according to any of Aspects 1 to 4, wherein, taking a coordinate axis in the vertical direction, the coordinate value at the upper end surface of the plug is 0 and the coordinate value at the lower end surface is H, the vertical height D of the gas flow channel satisfies the relationship D≧1.5D1 at least in a range of coordinate values ​​from 0.5×H to 1.0×H. [Aspect 6] The semiconductor manufacturing equipment member according to any of Aspects 1 to 5, wherein the vertical height D of the gas flow channel satisfies the relationship D1≦D<1.5D1 at least in a range of coordinate values ​​from 0 to less than 0.1×H. [Aspect 7] The semiconductor manufacturing equipment member according to any one of Aspects 1 to 6, wherein the plug has a plurality of the gas flow paths, and all of the plurality of gas flow paths satisfy the relationship D1 < D2. [Aspect 8] The semiconductor manufacturing equipment member according to any one of Aspects 1 to 7, wherein a fracture toughness value (KIC) of a portion of the plug formed by a dense body is greater than a fracture toughness value (KIC) of the ceramic substrate.[Aspect 9] A semiconductor manufacturing equipment component comprising: a ceramic substrate having an upper surface and a lower surface for mounting a wafer; a plug placement hole vertically penetrating the ceramic substrate; and a plug embedded in the plug placement hole, wherein the plug is made of a dense body and has an upper end portion having an upper end surface exposed on the upper surface side, a lower end surface exposed on the lower surface side, and a gas flow path extending from a side opening provided on a side surface of the upper end portion through the dense body to a lower end opening provided on the lower surface. [Aspect 10] The semiconductor manufacturing equipment component of Aspect 9, wherein a recess is formed in the upper surface for mounting a wafer, and the upper end portion of the plug protrudes from a bottom surface of the recess so as to expose the side opening. [Aspect 11] The semiconductor manufacturing equipment component of Aspect 9 or 10, wherein the vertical height D of the gas flow path is 10 to 300 μm. [Aspect 12] The semiconductor manufacturing equipment member according to any one of Aspects 9 to 11, wherein the fracture toughness (K) of the portion of the plug formed by the dense body is greater than the fracture toughness (K) of the ceramic substrate. [Aspect 13] The semiconductor manufacturing equipment member according to any one of Aspects 9 to 12, wherein the plug has a plurality of the gas flow channels, each of the plurality of gas flow channels extending from a side opening provided on a side surface of the upper end portion, through the interior of the dense body, to a bottom opening provided on the bottom surface.

[0014] A semiconductor manufacturing equipment member according to one embodiment of the present invention is effective in suppressing discharge occurring between a wafer and a base plate.

[0015] 1-3 is a schematic vertical cross-sectional view of a semiconductor manufacturing equipment member according to a first embodiment of the present invention; FIG. 1-4 is a schematic vertical cross-sectional view (in the case of one gas flow path) passing through the central axis of a plug included in the semiconductor manufacturing equipment member according to the first embodiment of the present invention; FIG. 1-5 is a schematic plan view of a plug included in the semiconductor manufacturing equipment member according to the first embodiment of the present invention (in the case of four gas flow paths); FIG. 1-6 is a schematic vertical cross-sectional view for explaining the structure of a gas flow path near the upper end opening of the plug shown in FIG. 1-2; FIG. 1-7 is a schematic vertical cross-sectional view for explaining the structure of a gas flow path near the lower end opening of the plug shown in FIG. 1-3; FIG. 1-8 is a schematic plan view of a ceramic substrate included in the semiconductor manufacturing equipment member according to the first embodiment of the present invention; FIG. 1-9 is a schematic vertical cross-sectional view of a semiconductor manufacturing equipment member according to a second embodiment of the present invention; FIG. 1-10 is a schematic vertical cross-sectional view (in the case of one gas flow path) passing through the central axis of a plug included in the semiconductor manufacturing equipment member according to the second embodiment of the present invention;

[0016] Next, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes, improvements, and the like may be made based on the common knowledge of those skilled in the art without departing from the spirit of the present invention. Furthermore, in this specification, "upper" and "lower" are used for convenience to represent the relative positional relationship when a semiconductor manufacturing equipment component is placed on a horizontal surface with the upper surface for mounting a ceramic substrate wafer facing up, and do not represent an absolute positional relationship. Therefore, depending on the orientation of the semiconductor manufacturing equipment component, "upper" and "lower" may become "lower" and "upper," "left" and "right," or "front" and "rear."

[0017] 1-1 , a semiconductor manufacturing equipment member 10 according to a first embodiment of the present invention includes a ceramic substrate 20 having an upper surface 21 for placing a wafer W thereon and a lower surface 23 opposite the upper surface 21, a plug placement hole 50 that passes through the ceramic substrate 20 in the vertical direction, and a plug 55 embedded in the plug placement hole 50. The semiconductor manufacturing equipment member 10 also includes a base plate 30 bonded to the lower surface 23 of the ceramic substrate 20 via a bonding layer 40, and a gas supply path 60 that passes through the base plate 30 and the bonding layer 40 and supplies a gas to the plug 55.

[0018] (1-1. Ceramic Substrate) The upper surface 21 of the ceramic substrate 20 has a wafer mounting surface on which a wafer W is mounted. The ceramic substrate 20 also incorporates an electrode 22. As shown in FIGS. 1-1 and 1-6, an annular seal band 21a is formed on the upper surface 21 of the ceramic substrate 20 along its outer edge, and multiple protrusions 21b are formed over the entire inner surface of the seal band 21a. The shape of the protrusions 21b is not limited, but may be, for example, a cylinder or a rectangular column. The seal band 21a and the protrusions 21b preferably have the same height, which may be, for example, 5 to 100 μm, typically 10 to 30 μm. The electrode 22 is a planar electrode used as an electrostatic electrode and is connected to an external DC power source via a power supply member (not shown). A low-pass filter may be disposed along the power supply member. The power supply member is electrically insulated from the bonding layer 40 and the base plate 30. When a DC voltage is applied to this electrode 22, the wafer W is attracted and fixed to the wafer mounting surface (specifically, the upper surfaces of the seal bands 21a and the protrusions 21b) by electrostatic attraction, and when the application of the DC voltage is stopped, the attracting and fixing of the wafer W to the wafer mounting surface is released. Note that the portion of the upper surface 21 of the ceramic substrate 20 where the seal bands 21a and the protrusions 21b are not provided is referred to as a reference surface 21c.

[0019] Instead of or in addition to the electrostatic electrode, a heater electrode (resistance heating element) may be built in as the electrode 22. In this case, a heater power supply is connected to the heater electrode. The ceramic substrate 20 may have one layer of electrodes built in, or two or more layers of electrodes built in with a gap between them.

[0020] The ceramic substrate 20 may be a circular plate (e.g., 300-400 mm in diameter) made of ceramic, such as alumina sintered body or aluminum nitride sintered body. The thickness of the ceramic substrate 20 is not limited, but from the viewpoint of increasing the fixing strength of the plug 55, the thickness from the upper opening 50a to the lower opening 50b is preferably 1 mm or more. Furthermore, from the viewpoint of reducing heat transfer of the ceramic substrate 20 and reducing manufacturing costs, the thickness is preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less. Therefore, the thickness from the upper opening 50a to the lower opening 50b is, for example, preferably 1-5 mm, more preferably 1-3 mm, and even more preferably 1-2 mm. Here, the thickness from the upper opening 50a to the lower opening 50b refers to the distance from the center of gravity of the upper opening 50a to the center of gravity of the lower opening 50b. The height position of the upper opening 50a is equal to the height position of the reference plane 21c of the upper surface 21 of the ceramic substrate 20. The height position of the lower opening 50 b is equal to the height position of the lower surface 23 of the ceramic substrate 20 .

[0021] (1-2. Plug Arrangement Hole) As shown in FIG. 1-1, the plug arrangement hole 50 is a hole that penetrates the ceramic substrate 20 in the vertical direction from the upper opening 50a to the lower opening 50b. The plug arrangement hole 50 functions as a gas passage that extends from the lower surface 23 of the ceramic substrate 20 to the reference surface 21c of the upper surface 21. One plug arrangement hole 50 may be provided, but it is preferable to provide multiple plug arrangement holes 50. FIG. 1-6 shows multiple (six in this case) plug arrangement holes 50, each with a plug 55 embedded therein.

[0022] The horizontal opening diameter of the plug arrangement hole 50 (meaning the equivalent circular diameter when the cross section of the plug arrangement hole is not circular) is not limited, but can be, for example, within a range of 1 to 5 mm at any height position, and typically within a range of 3 to 4 mm. The diameter of the plug arrangement hole 50 may be constant or may vary from the lower surface 23 to the upper surface 21 of the ceramic substrate 20. In one embodiment, the diameter of the plug arrangement hole 50 decreases from top to bottom, and the plug arrangement hole 50 may have a tapered inner circumferential surface 50c in which the area of ​​the upper opening 50a is larger than the area of ​​the lower opening 50b. By having such a tapered inner circumferential surface 50c, the plug 55 can be easily stopped at a predetermined height position in the plug arrangement hole 50 when embedding the plug 55 in the plug arrangement hole 50, thereby achieving the effect of enabling the plug 55 to be embedded in the plug arrangement hole 50 with high positioning accuracy. Furthermore, while the plug 55 is difficult to remove downward, it is relatively easy to remove upward, resulting in the effect of facilitating replacement of the plug 55. Furthermore, the increased creepage distance also has the effect of suppressing discharge. The plug placement hole 50 may have a space in the shape of, for example, a truncated cone or a truncated pyramid.

[0023] The inclination angle α of the inner circumferential surface 50c of the plug arrangement hole 50 with respect to the lower opening 50b is preferably 70° or more, and more preferably 75° or more, from the viewpoints of increasing the fixing strength of the plug 55 and preventing the volume of the plug 55 from becoming excessively large to ensure space for arranging electrodes around it. Furthermore, the inclination angle α is preferably 87° or less, and more preferably 85° or less, from the viewpoints of improving the positioning accuracy of the plug in the height direction when the plug 55 is press-fitted downward into the plug arrangement hole 50, making the plug 55 easier to replace, and lengthening the creepage distance to suppress discharge. Therefore, the inclination angle α is preferably, for example, 70° to 87°, and more preferably 75° to 85°.

[0024] (1-3. Plug) A plug 55 is embedded in the plug placement hole 50. FIG. 1-2 shows a schematic longitudinal cross-sectional view (in the case of one gas flow path) passing through the central axis of the plug 55. FIG. 1-3 shows a schematic plan view of the plug 55 (in the case of four gas flow paths). The plug 55 is composed of a dense body 55c, and has an upper end surface 55a exposed on the upper surface 21 side of the ceramic substrate 20, a lower end surface 55b exposed on the lower surface 23 side of the ceramic substrate 20, and a gas flow path 55d extending from an upper end opening 55a1 provided in the upper end surface 55a, through the interior of the dense body 55c, to a lower end opening 55b1 provided in the lower end surface 55b.

[0025] In this specification, the dense body 55c refers to a portion of the plug 55 that has a porosity of 5% or less. The partial porosity of the plug 55 is measured by the following method. First, the plug 55 is cut so that a cross section passing through the central axis extending in the vertical direction of the plug 55 is exposed. Next, the portion of the cross section to be measured for porosity is observed at a magnification of 3000 times and a resolution of 2200 μm using a scanning electron microscope (SEM). 2 The area ratio of pores observed in the area is determined. Specifically, the SEM image is analyzed, and a threshold is determined using discriminant analysis (Otsu's binarization) from the brightness distribution of the brightness data of pixels in the image. Then, based on the determined threshold, each pixel in the image is binarized into an object portion and a pore portion, and the area of ​​the object portion and the area of ​​the pore portion are calculated. Then, the ratio of the area of ​​the pore portion to the total area (the total area of ​​the object portion and the pore portion) is determined, and this is the porosity of the portion to be measured.

[0026] In the first embodiment, gas flowing in through a lower end opening 55b1 provided on the lower end surface 55b of the plug 55 flows through a gas flow channel 55d provided inside the dense body 55c and can flow out through an upper end opening 55a1 provided on the upper end surface 55a of the plug 55. One plug 55 may be provided with only one gas flow channel 55d, or two or more. From the viewpoint of ensuring a sufficient gas flow rate, one plug 55 is preferably provided with 1 to 10 gas flow channels 55d, and more preferably 4 to 10. For simplicity, FIG. 1-2 shows one gas flow channel 55d. FIG. 1-3 shows the upper end openings 55a1 that serve as outlets for each of the four gas flow channels 55d. The gas flow channels 55d may be configured as straight lines, curves, or a combination of both. However, from the viewpoint of suppressing discharge, a shape in which the flow channel length is longer than the vertical length of the plug 55, such as a bent shape such as a spiral or zigzag shape, is preferred.

[0027] There are no particular limitations on the shape of the upper end opening 55a1. For example, the opening shape can be formed by a straight line, a curve, or a combination of both. Specifically, the flow path shape can be rectangular. Among these, a long and narrow rectangular shape is preferable for the flow path shape in order to ensure the opening area and the area of ​​the plug.

[0028] The gas flow path 55d may be hollow, but at least a portion thereof may be porous as long as it allows gas flow. When at least a portion of the gas flow path 55d is porous, gas flowing in from the lower end opening 55b1 of the plug 55 flows through the gas flow path 55d formed by a large number of continuous pores and flows out from the upper end opening 55a1 of the plug 55. The outflowing gas is supplied between the wafer W and the ceramic substrate 20. Because the three-dimensionally (e.g., three-dimensionally network-like) continuous pores present in the porous material form the gas flow path, the effective flow path length within the gas flow path 55d is longer than when the gas flow path 55d is hollow, resulting in the effect of making it less likely for discharge to occur. It is also possible to form one or more additional gas flow paths within the porous gas flow path.

[0029] Therefore, the gas flow passage 55d may be hollow or porous. It is preferable that at least a portion of the gas flow passage 55d is porous. The gas flow passage 55d being hollow means that the porosity of the gas flow passage 55d is 100%. The gas flow passage 55d being porous means that the porosity of the gas flow passage 55d is greater than 5% and less than 100%. When the gas flow passage 55d is porous, a larger porosity of the gas flow passage 55d is preferable to reduce the airflow resistance. Therefore, the porosity of the gas flow passage 55d is preferably 10% or more, and more preferably 40% or more. On the other hand, the porosity of the gas flow passage 55d is preferably 50% or less in order to increase the flow passage length of the plug 55 and ensure structural strength. Therefore, the porosity of the gas flow passage 55d is preferably 10% or more and 50% or less, and more preferably 40% or more and 50% or less. The porosity of the gas flow passage 55d is measured by mercury intrusion porosimetry (JIS R1655:2003).

[0030] 1-4 shows a schematic example of the structure of the gas flow path 55d near the upper end opening 55a1 of the plug 55. FIG. 1-5 shows a schematic example of the structure of the gas flow path 55d near the lower end opening 55b1 of the plug 55. During wafer processing, gas molecules present between the wafer W and the ceramic substrate 20 are ionized, and the resulting electrons may accelerate toward the ceramic substrate 20 and collide with the upper surface 21 of the ceramic substrate 20. Since the higher the gas velocity, the more likely discharge is to occur, shortening the distance between the wafer W and the ceramic substrate 20 is effective in suppressing the gas velocity.

[0031] However, if the upper end opening 55a1 of the plug 55 is exposed on the upper surface 21 of the ceramic substrate 20, the electrons flowing in from the upper end opening 55a1 are further accelerated before colliding with the surface 55d1 of the gas flow channel 55d. Therefore, it is desirable to shorten the distance from the upper end opening 55a1 to the surface 55d1 of the gas flow channel 55d, because this shortens the acceleration time required for the electrons flowing in the upper end opening 55a1 to collide with the surface of the gas flow channel 55d. On the other hand, from the viewpoint of ensuring the gas flow rate required for supplying gas between the wafer W and the ceramic substrate 20, it is advantageous to lengthen the distance from the lower end opening 55b1 of the gas flow channel 55d to the surface 55d1 of the gas flow channel 55d.

[0032] Therefore, in one embodiment, for at least one gas flow path 55d of the plug 55, the maximum height D1 in the vertical direction from the upper end opening 55a1 to the surface 55d1 of the gas flow path 55d and the maximum height D2 in the vertical direction from the lower end opening 55b1 to the surface of the gas flow path 55d satisfy the relationship D1 < D2. When the plug 55 has multiple gas flow paths 55d, it is preferable that the relationship D1 < D2 be satisfied for all of the multiple gas flow paths 55d.

[0033] Regarding preferred embodiments of the plug 55, such as the maximum height D1, maximum height D2, and height D of the gas flow passage 55d described below, when the plug 55 has multiple gas flow passages 55d, it is preferable that all of the multiple gas flow passages 55d satisfy the conditions for those preferred embodiments.

[0034] For at least one gas flow path 55d of the plug 55, it is preferable that the relationship D1 / D2 ≦ 0.9 is satisfied, more preferably that the relationship D1 / D2 ≦ 0.7 is satisfied, and even more preferably that the relationship D1 / D2 ≦ 0.5 is satisfied. On the other hand, from the viewpoint of ensuring the gas flow rate necessary for supplying gas between the wafer W and the ceramic substrate 20, it is desirable not to make D1 / D2 excessively small. Therefore, it is preferable that the relationship 0.1 ≦ D1 / D2 is satisfied, more preferably that the relationship 0.3 ≦ D1 / D2 is satisfied, and even more preferably that the relationship 0.5 ≦ D1 / D2 is satisfied. Therefore, for example, it is preferable that the relationship 0.1 ≦ D1 / D2 ≦ 0.9 is satisfied. Furthermore, it is also possible to satisfy the relationship 0.5 ≦ D1 / D2 ≦ 0.7 or the relationship 0.3 ≦ D1 / D2 ≦ 0.5.

[0035] It is preferable that the vertical height D of the gas flow passage 55d increases continuously or stepwise as the gas flow passage 55d advances downward.

[0036] The maximum height D1 in the vertical direction from the upper end opening 55a1 to the surface 55d1 of the gas flow channel 55d refers to the length of the longest straight line that can be extended downward from the upper end opening 55a1 to the surface 55d1 of the gas flow channel 55d, as shown in Fig. 1-4. Similarly, the maximum height D2 in the vertical direction from the lower end opening 55b1 to the surface 55d1 of the gas flow channel 55d refers to the length of the longest straight line that can be extended upward from the lower end opening 55b1 to the surface 55d1 of the gas flow channel 55d, as shown in Fig. 1-5.

[0037] The smaller the maximum height D1, the greater the effect of suppressing discharge. Furthermore, if the maximum height D1 is set with a safety margin in mind, the risk of discharge can be reduced even when the vertical distance from the back surface of the wafer W to the surface 55d1 of the gas flow path 55d exposed at the upper end opening 55a1 increases due to some factor. Possible reasons for this include, for example, (a) chipping occurring near the upper end opening 55a1 of the plug 55, resulting in chipping of the gas flow path 55d, (b) the plug 55 sinking below its predetermined position when embedded in the plug placement hole 50, or (c) low machining accuracy of the plug 55 itself. On the other hand, from the viewpoint of ensuring the gas flow rate required to supply gas between the wafer W and the ceramic substrate 20, a larger maximum height D1 is desirable. Therefore, considering the balance between these two factors, the maximum height D1 is preferably 10 to 300 μm, more preferably 40 to 100 μm, and even more preferably 60 to 100 μm.

[0038] While a larger maximum height D2 is desirable from the viewpoint of ensuring the gas flow rate required for supplying gas between the wafer W and the ceramic substrate 20, it is also desirable not to make the maximum height D2 excessively large from the viewpoints of ensuring the flow path length and the plug strength. Therefore, taking into consideration the balance between these two, the maximum height D2 is preferably 50 to 500 μm, more preferably 50 to 300 μm, and even more preferably 100 to 200 μm.

[0039] From the viewpoint of ensuring the gas flow rate required for supplying gas between the wafer W and the ceramic substrate 20, it is preferable that the vertical height D of the gas flow passage 55d be large, except for the vicinity of the upper end surface 55a of the plug 55, where the vertical height D of the gas flow passage 55d needs to be set small to reduce the risk of discharge. Therefore, taking a coordinate axis in the vertical direction (see FIG. 1-2 ), and assuming that the coordinate value at the upper end surface 55a of the plug 55 is 0 and the coordinate value at the lower end surface 55b is H, the vertical height D of the gas flow passage 55d preferably satisfies the relationship D≧1.5D1, and more preferably satisfies the relationship D≧2D1, within a range of coordinate values ​​at least from 0.5×H to 1.0×H, preferably at least from 0.1×H to 1.0×H. However, from the viewpoint of reducing the risk of discharge by ensuring the flow passage length and from the viewpoint of ensuring the plug strength, it is desirable not to make the vertical height D of the gas flow passage 55d excessively large. Specifically, in a coordinate value range of at least 0.5×H to 1.0×H, and preferably in a coordinate value range of at least 0.1×H to 1.0×H, the vertical height D of the gas flow path 55d preferably satisfies the relationship 30D≧D, more preferably satisfies the relationship 20D≧D, and even more preferably satisfies the relationship 10D≧D. Therefore, for example, in a coordinate value range of at least 0.5×H to 1.0×H, and preferably in a coordinate value range of at least 0.1×H to 1.0×H, the vertical height D of the gas flow path 55d preferably satisfies the relationship 30D≧D≧1.5D, more preferably satisfies the relationship 20D≧D≧2D, and even more preferably satisfies the relationship 10D≧D≧2D.

[0040] In order to reduce the risk of discharge, it is preferable to set not only the maximum vertical height D1 from the upper end opening 55a1 of the plug 55 to the surface 55d1 of the gas flow passage 55d but also the vertical height D of the gas flow passage 55d small, provided that the height D is not less than the maximum height D1 near the upper end surface 55a of the plug 55. Specifically, it is preferable that the vertical height D of the gas flow passage 55d satisfy the relationship D1≦D<1.5D1 at least in the range of coordinate values ​​from 0 to less than 0.1×H.

[0041] The vertical height D of the gas flow path 55d at a specific coordinate value is the length of the longest straight line that is extended in the vertical direction connecting the opposing surfaces 55d1 of the gas flow path 55d and that can intersect or be tangent to a horizontal plane passing through the specific coordinate value. FIG. 1-5 schematically shows the height D of the gas flow path 55d at the coordinate value 0.95H to explain this. As can be seen from FIG. 1-5, there are many straight lines that are extended in the vertical direction connecting the opposing surfaces 55d1 of the gas flow path 55d and that can intersect or be tangent to a horizontal plane (the horizontal line in the figure) passing through the coordinate value 0.95H. Here, for simplicity, five straight lines that satisfy the condition are drawn. The lengths of the five straight lines are each D a , D b , D c , D d , D e The longest straight line among these is D e Therefore, the height D of the gas flow path 55d at the coordinate value 0.95H is D e The vertical height D of the gas flow path 55d can be measured, for example, by obtaining three-dimensional shape information of the gas flow path 55d using X-ray CT. Regardless of the above definition, the height D of the gas flow path 55d at coordinate value 0 is set to D1, and the height D of the gas flow path 55d at coordinate value H is set to D2.

[0042] In order to prevent chipping from occurring near the upper end opening 55a1 of the plug 55, it is desirable for the plug 55 to have a large fracture toughness value (K). Specifically, it is preferable that the fracture toughness value (K) of the portion of the plug 55 formed by the dense body 55c is greater than the fracture toughness value (K) of the ceramic substrate 20. Since the processing conditions for semiconductor manufacturing equipment members are often set based on the ceramic substrate 20, if the fracture toughness value (K) of the portion of the plug 55 formed by the dense body 55c is greater than the fracture toughness value (K) of the ceramic substrate 20, the risk of chipping occurring in the plug 55 is reduced.

[0043] The fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c is 2 MPa m1 / 2 It is preferable that the viscosity is 3 MPa m or more. 1 / 2 More preferably, it is 4 MPa m 1 / 2 Although no particular upper limit is set for the fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c, from the viewpoint of ease of manufacture, it is preferable that the KIC be 13 MPa m 1 / 2 It is preferable that the viscosity is 12 MPa m or less. 1 / 2 More preferably, it is 11 MPa m or less. 1 / 2 Therefore, the fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c is 2 to 13 MPa m 1 / 2 Preferably, the pressure is 3 to 12 MPa m 1 / 2 More preferably, it is 4 to 11 MPa m 1 / 2 It is even more preferable that:

[0044] The fracture toughness (KIC) of the portion of the plug 55 formed by the dense body 55c and the ceramic substrate 20 is measured in accordance with the SEPB method defined in JIS R1607:2015.

[0045] The material constituting the plug 55 can be an electrically insulating ceramic, and can contain, for example, one or more selected from aluminum oxide, aluminum nitride, and silicon dioxide. The plug 55 can also be made of only one or two selected from aluminum oxide, aluminum nitride, and silicon dioxide, excluding impurities. Quartz is preferable as the silicon dioxide. In particular, in order to control the fracture toughness value (KIC) of the portion of the plug 55 constituting the dense body 55c within the above-mentioned range, it is preferable to construct the portion of the plug 55 constituting the dense body 55c of the plug 55 from a ceramic material with high fracture toughness, such as alumina (aluminum oxide).

[0046] Furthermore, in order to maintain the fixing strength of the plug 55 embedded in the plug placement hole 50, it is preferable that the difference in thermal expansion coefficient between the plug 55 and the ceramic substrate 20 is small. For this reason, it is preferable that the material constituting the plug 55 and the material constituting the ceramic substrate 20 both contain one or more selected from aluminum oxide and aluminum nitride, and it is more preferable that the material compositions are the same.

[0047] The height position of the upper end surface 55a of the plug 55 is not limited. Therefore, the height position of the upper end surface 55a of the plug 55 may be the same as or different from the reference surface 21c of the ceramic substrate 20. When the upper end surface 55a of the plug 55 is made lower than the reference surface 21c, it is preferable to arrange it at a position lower by 0.5 mm or less (preferably 0.2 mm or less, more preferably 0.1 mm or less) in order to suppress the occurrence of discharge. When the upper end surface 55a of the plug 55 is made higher than the reference surface 21c, there is no particular limitation as long as it is lower than the upper surface of the protrusion 21b and the outflow of gas from the plug 55 is not hindered.

[0048] There is no particular limitation on the height position of the lower end surface 55b of the plug 55. Therefore, the height position of the lower end surface 55b of the plug 55 may be the same height as the lower surface 23 of the ceramic substrate 20, or may be a different height. For example, the lower end surface 55b of the plug 55 may protrude downward from the lower surface 23 of the ceramic substrate 20, or the lower end surface 55b of the plug 55 may be located above the lower surface 23 of the ceramic substrate 20.

[0049] The outer peripheral surface 55e of the plug 55 and the inner peripheral surface 50c of the plug arrangement hole 50 may be bonded via an adhesive, but it is preferable that they be directly fitted together without using an adhesive. Direct fitting between the two prevents a gap from forming between the plug 55 and the plug arrangement hole 50 due to deterioration of the adhesive caused by corrosion or erosion, etc. This has the advantage of suppressing discharge and detachment of the plug 55 caused by deterioration of the adhesive.

[0050] Furthermore, as shown in FIG. 1-1 , when observing a longitudinal cross section obtained by cutting the ceramic substrate 20 in the thickness direction, from the viewpoint of improving the fixing strength of the plug 55, it is preferable that the inner circumferential surface 50c of the plug arrangement hole 50 contacts the outer circumferential surface 55e of the plug 55 in a parallel positional relationship. In other words, the outer circumferential surface 55e of the plug 55 has the same inclination angle as the inner circumferential surface 50c of the plug arrangement hole 50. Therefore, in a preferred embodiment, the plug 55 has an outer shape that is the same shape as the plug arrangement hole 50 (e.g., a truncated cone or a truncated pyramid). This makes it possible to increase the area over which the inner circumferential surface 50c of the plug 55 contacts the outer circumferential surface 55e of the plug 55, thereby obtaining high fixing strength.

[0051] An example of a direct fitting method is to embed the plug 55 by press-fitting it into the plug arrangement hole 50. In this case, in order to obtain the desired fixing strength, it is preferable that the horizontal cross-sectional diameter of the plug 55 at any height position before press-fitting be slightly larger (for example, by about 5 to 20 μm in equivalent circle diameter) than the horizontal cross-sectional diameter of the plug arrangement hole 50 at the same height position. Another example of a direct fitting method is to thread a male thread portion provided on the outer peripheral surface 55 e of the plug 55 into a female thread portion provided on the inner peripheral surface 50 c of the plug arrangement hole 50.

[0052] A method for manufacturing the plug 55 having such a dense body 55c and a gas flow path 55d penetrating therethrough includes, for example, firing a green body formed using additive manufacturing technology such as a 3D printer. The plug 55 may also be formed by mold casting. Details of mold casting are disclosed, for example, in Japanese Patent No. 5458050. In mold casting, a ceramic slurry containing ceramic powder, a solvent, a dispersant, and a gelling agent is injected into the forming space of a mold, and the gelling agent is chemically reacted to gel the ceramic slurry, thereby forming a green body within the mold. In mold casting, a green body may be formed within the mold using an outer mold and a core (having the same shape as the gas flow path 55d) made of a low-melting-point material such as wax. The green body may then be produced by heating the green body to a temperature above the melting point of the mold, melting and removing the green body or burning it away. Next, a porous raw material is placed in the cavity of the resulting green body corresponding to the gas flow path 55d. Specifically, for example, a raw material made by adding a pore-forming material such as resin or wax to an aggregate such as ceramic powder is made into a slurry or paste by adding a solvent as needed, and the resulting mixture is filled into the cavities corresponding to the gas flow paths 55d of the compact, and finally the entire mixture is fired. By this firing, the pore-forming material in the porous raw material disappears, forming porous portions, and a plug 55 in which the dense body and porous portions are integrated is obtained.

[0053] The porosity of the plug 55 can be controlled, for example, by adjusting the content of the pore-forming material in the raw material composition before firing the ceramics that constitute the plug 55. For example, to densify the plug 55, the amount of the pore-forming material may be reduced or may not be used at all.

[0054] (1-4. Base Plate) The base plate 30 may be, for example, a circular plate (a circular plate with the same diameter as or larger than the ceramic substrate 20) with good electrical and thermal conductivity. Referring to FIG. 1-1 , a refrigerant flow path 32 through which a refrigerant circulates may be formed inside the base plate 30. The refrigerant flowing through the refrigerant flow path 32 is preferably a liquid, and is preferably electrically insulating. Examples of electrically insulating liquids include a fluorine-based inert liquid. The refrigerant flow path 32 may be formed, for example, in a single stroke across the entire base plate 30 in a plan view from one end (inlet) to the other end (outlet). One end and the other end of the refrigerant flow path 32 are connected to a supply port and a recovery port of an external refrigerant device (not shown), respectively. The refrigerant supplied to one end of the refrigerant flow path 32 from the supply port of the external refrigerant device passes through the refrigerant flow path 32, returns from the other end of the refrigerant flow path 32 to the recovery port of the external refrigerant device, has its temperature adjusted, and is then supplied again from the supply port to one end of the refrigerant flow path 32. The base plate 30 is connected to a radio frequency (RF) power source and can also be used as an RF electrode.

[0055] Examples of materials constituting the base plate 30 include metal materials and composite materials of metal and ceramic. Metal materials include Al, Ti, Mo, W, and alloys thereof. Metal-ceramic composite materials include metal matrix composites (MMCs) and ceramic matrix composites (CMCs). Specific examples of such composite materials include materials containing Si, SiC, and Ti (also known as SiSiCTi), porous SiC impregnated with Al and / or Si, and composites of Al2O3 and TiC. A material in which porous SiC is impregnated with Al is called AlSiC, and a material in which porous SiC is impregnated with Si is called SiSiC. It is preferable to select a material for the base plate 30 with a thermal expansion coefficient close to that of the material for the ceramic substrate 20. For example, if the ceramic substrate 20 is made of alumina, the base plate is preferably made of SiSiCTi or AlSiC.

[0056] (1-5. Bonding Layer) As shown in FIG. 1-1 , the upper surface 31 of the base plate 30 can be bonded to the lower surface 23 of the ceramic substrate 20 via a bonding layer 40. The bonding layer 40 is formed, for example, by thermal compression bonding (TCB). TCB refers to a known method in which a metal bonding material is sandwiched between two components to be bonded and the two components are pressure-bonded while heated to a temperature below the solidus temperature of the metal bonding material. The bonding layer 40 can be formed, for example, by a metal bonding layer using an Al-Mg bonding material or an Al-Si-Mg bonding material. The bonding layer 40 may also be formed from solder or a metal brazing material. Furthermore, the bonding layer 40 may be formed from a resin adhesive layer instead of a metal bonding layer. Examples of materials for the resin adhesive layer include a silicone resin adhesive, an epoxy resin adhesive, and an acrylic resin adhesive. To improve the uniformity of the thickness of the resin adhesive layer, a spacer (not shown) may be disposed between the upper surface 31 of the base plate 30 and the lower surface 23 of the ceramic substrate 20 .

[0057] The bonding layer 40 has a through hole 42. The through hole 42 is located opposite the large-diameter portion 34a of the gas hole 34 (described later). The through hole 42 is located coaxially with the large-diameter portion 34a, and the diameter of the through hole 42 may be the same as the diameter of the large-diameter portion 34a. In this specification, "matching" includes not only perfect matching but also substantial matching (e.g., within a tolerance range) (the same applies below). Multiple through holes 42 may be provided for one plug 55. In this case, the multiple through holes 42 are preferably provided point-symmetrically with respect to the central axis extending vertically of the plug 55. Providing multiple through holes 42 rather than a single large through hole 42 allows the size of each through hole 42 to be smaller, thereby reducing the risk of discharge. Providing multiple through holes 42 also ensures the necessary gas flow rate.

[0058] 1-1 , the gas supply path 60 for supplying gas to the plug 55 through the base plate 30 and the bonding layer 40 has, for example, a through hole 42 that passes through the bonding layer 40 in the vertical direction, and a gas hole 34 that communicates with the through hole 42 and passes through the base plate 30 from the upper surface 31 to the lower surface 33. A large diameter portion 34a may also be provided on the upper surface 31 of the base plate 30 at a position facing the through hole 42. By having the through hole 42 and further the large diameter portion 34a, when placing the plug 55 in the plug placement hole 50, even if there is a manufacturing error in the plug placement hole 50 and / or the plug 55, a space that allows the plug 55 to enter is created, and therefore such manufacturing error can be absorbed.

[0059] The configuration of the gas supply path 60 is not particularly limited. For example, as shown in FIG. 3 , a semiconductor manufacturing equipment member 10 according to another embodiment of the present invention may be provided with one or more ring portions 64a, each of which extends concentrically with the base plate 30 in a plan view; one or more gas inlet portions 64b that supply gas introduced from the lower surface 33 of the base plate 30 to the ring portion 64a; and a gas distributor 64c that distributes the gas from the ring portion 64a to each plug 55. In this embodiment, the upper end of the distributor 64c communicates with the through-hole 42 in the bonding layer 40. In FIG. 3 , the same components as those in the embodiment shown in FIG. 1-1 are denoted by the same reference numerals. The number of gas inlet portions 64b may be fewer than the number of distributor portions 64c, for example, one. This allows the number of gas pipes connected to the base plate 30 to be fewer than the number of plugs 55. Other auxiliary passages (not shown) may also be provided.

[0060] (1-7. Other) Lift pin holes may be provided through the semiconductor manufacturing equipment member 10. The lift pin holes are holes for inserting lift pins that move the wafer W up and down relative to the upper surface 21 of the ceramic substrate 20. When the wafer W is supported by, for example, three lift pins, the lift pin holes are provided in three locations.

[0061] 2-1 , a semiconductor manufacturing equipment member 10 according to a second embodiment of the present invention includes a ceramic substrate 20 having an upper surface 21 for placing a wafer W thereon and a lower surface 23 opposite the upper surface 21, a plug placement hole 50 that passes through the ceramic substrate 20 in the vertical direction, and a plug 55 embedded in the plug placement hole 50. The semiconductor manufacturing equipment member 10 also includes a conductive base plate 30 bonded to the lower surface 23 of the ceramic substrate 20 via a bonding layer 40, and a gas supply path 60 that passes through the base plate 30 and the bonding layer 40 and supplies a gas to the plug 55.

[0062] FIG. 2-2 shows a schematic longitudinal cross-sectional view of the plug 55. The plug 55 is composed of a dense body 55c, and has an upper end 55f having an upper end surface 55a exposed on the upper surface 21 side of the ceramic substrate 20, a lower end surface 55b exposed on the lower surface 23 side of the ceramic substrate 20, and a gas flow path 55d extending from a side opening 55f2 provided on a side surface 55f1 of the upper end 55f, penetrating the inside of the dense body 55c, to a lower end opening 55b1 provided on the lower end surface 55b. Therefore, the plug 55 does not have an opening for the gas flow path 55d on the upper end surface 55a. This prevents electrons accelerated to the upper end surface 55a from flowing into and colliding with the gas flow path 55d during wafer processing, thereby reducing the risk of discharge.

[0063] As described above, in this specification, the dense body 55c refers to a portion having a porosity of 5% or less among the portions constituting the plug 55. The partial porosity of the plug 55 is measured by the method described above.

[0064] In the second embodiment, gas flowing in through a lower end opening 55b1 provided in a lower end surface 55b of the plug 55 flows through a gas flow path 55d provided inside the dense body 55c and can flow out through a side opening 55f2 provided in a side surface 55f1 of an upper end 55f of the plug 55. One plug 55 may be provided with only one gas flow path 55d, or two or more gas flow paths 55d. The gas flow path 55d may be configured as a straight line, a curved line, or a combination of both. However, from the viewpoint of suppressing discharge, it is preferable that the gas flow path 55d has a shape such that the length of the flow path is longer than the length of the plug 55 in the vertical direction, for example, a bent shape such as a spiral or zigzag shape.

[0065] When the plug 55 has multiple gas flow paths 55d, it is preferable that each of the multiple gas flow paths 55d extends from a side opening 55f2 provided on a side surface 55f1 of the upper end 55f, through the inside of the dense body 55c, and to a lower end opening 55b1 provided on the lower end surface 55b.

[0066] The upper end 55f of the plug 55 refers to a range of coordinate values ​​from 0 to 0.1×H, where the coordinate axis is taken in the vertical direction (see FIG. 2-2 ) and the coordinate value at the upper end surface 55a of the plug 55 is 0 and the coordinate value at the lower end surface 55b is H. In order to ensure the flow path length and to reduce the height from the wafer placement surface to the side opening 55f2, the side opening 55f2 is preferably provided within a range of coordinate values ​​from 0.01×H to 0.06×H, more preferably within a range of coordinate values ​​from 0.01×H to 0.05×H, and even more preferably within a range of coordinate values ​​from 0.01×H to 0.04×H.

[0067] The gas flow path 55d may be hollow, but at least a portion thereof may be porous as long as it allows gas flow. When at least a portion of the gas flow path 55d is porous, gas flowing in from the lower end opening 55b1 of the plug 55 flows through the gas flow path 55d formed by a large number of continuous pores and exits from the side opening 55f2 at the upper end 55f of the plug 55. The exiting gas is supplied between the wafer W and the ceramic substrate 20. Because the three-dimensionally (e.g., three-dimensionally network-like) continuous pores present within the porous portion serve as the gas flow path, the effective flow path length within the gas flow path 55d is longer than when the gas flow path 55d is hollow, resulting in the effect of making it less likely for discharge to occur. It is also possible to form one or more additional gas flow paths within the porous gas flow path.

[0068] Therefore, the gas flow passage 55d may be hollow or porous. It is preferable that at least a portion of the gas flow passage 55d is porous. The gas flow passage 55d being hollow means that the porosity of the gas flow passage 55d is 100%. The gas flow passage 55d being porous means that the porosity of the gas flow passage 55d is greater than 5% and less than 100%. When the gas flow passage 55d is porous, a larger porosity of the gas flow passage 55d is preferable to reduce the airflow resistance. Therefore, the porosity of the gas flow passage 55d is preferably 10% or more, and more preferably 40% or more. On the other hand, the porosity of the gas flow passage 55d is preferably 50% or less in order to increase the flow passage length of the plug 55 and ensure structural strength. Therefore, the porosity of the gas flow passage 55d is preferably 10% or more and 50% or less, and more preferably 40% or more and 50% or less. The porosity of the gas flow passage 55d is measured by mercury intrusion porosimetry (JIS R1655:2003).

[0069] In the second embodiment, gas flows out through a side opening 55f2 provided on a side surface 55f1 of the upper end 55f of the plug 55. Therefore, a gas passage is required to ensure that the gas flowing out from the side opening 55f2 is supplied between the wafer W and the ceramic substrate 20. Therefore, in one embodiment, a recess 21d is formed in the upper surface 21 of the ceramic substrate 20 for supporting the wafer W, and the upper end 55f of the plug 55 protrudes from the bottom surface of the recess 21d so as to expose the side opening 55f2 (see the plug 55 on the left side in FIG. 2-1). The recess 21d can be formed below the reference surface 21c. In this case, even if accelerated electrons collide with the recess 21d, the insulating ceramics provide no path for conduction, reducing the risk of discharge. In another embodiment, the upper end 55f of the plug 55 protrudes from the reference surface 21c of the ceramic substrate 20 so as to expose the side opening 55f2 (see the plug 55 on the right side in FIG. 2-1).

[0070] The height position of the upper end surface 55a of the plug 55 is not limited. Therefore, the height position of the upper end surface 55a of the plug 55 may be the same as or different from the reference surface 21c of the ceramic substrate 20. When the upper end surface 55a of the plug 55 is made lower than the reference surface 21c, it is preferable to arrange it at a position lower by 0.5 mm or less (preferably 0.2 mm or less, more preferably 0.1 mm or less) in order to suppress the occurrence of discharge. When the upper end surface 55a of the plug 55 is made higher than the reference surface 21c, there is no particular limitation as long as it is lower than the upper surface of the protrusion 21b and the outflow of gas from the plug 55 is not hindered.

[0071] There is no particular limitation on the height position of the lower end surface 55b of the plug 55. Therefore, the height position of the lower end surface 55b of the plug 55 may be the same height as the lower surface 23 of the ceramic substrate 20, or may be a different height. For example, the lower end surface 55b of the plug 55 may protrude downward from the lower surface 23 of the ceramic substrate 20, or the lower end surface 55b of the plug 55 may be located above the lower surface 23 of the ceramic substrate 20.

[0072] In the second embodiment, there is no limitation on the vertical height D of the gas flow path as described in the first embodiment. Therefore, the vertical height D of the gas flow path 55d may be constant or may vary along the way. However, from the viewpoint of ensuring the gas flow rate required for supplying gas between the wafer W and the ceramic substrate 20, it is preferable that the vertical height D of the gas flow path 55d be large. Specifically, the vertical height D of the gas flow path 55d is preferably 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more, throughout the entire length of the gas flow path 55d. On the other hand, from the viewpoint of reducing the risk of discharge by ensuring the flow path length and ensuring the plug strength, the vertical height D of the gas flow path 55d is preferably 300 μm or less, more preferably 200 μm or less, throughout the entire length of the gas flow path 55d. The vertical height D of the gas flow path 55d is, for example, preferably 10 to 300 μm, more preferably 50 to 200 μm, and even more preferably 100 to 200 μm over the entire length of the gas flow path 55d. The definition of the vertical height D of the gas flow path 55d at a specific coordinate value when the coordinate axis is taken in the vertical direction is as described above.

[0073] From the viewpoint of suppressing the growth of microcracks that may occur in the plug, it is desirable for the plug 55 to have a large fracture toughness value (K). Specifically, it is preferable that the fracture toughness value (K) of the portion of the plug 55 formed by the dense body 55c is larger than the fracture toughness value (K) of the ceramic substrate 20. Since the processing conditions for semiconductor manufacturing equipment members are often set based on the ceramic substrate 20, if the fracture toughness value (K) of the portion of the plug 55 formed by the dense body 55c is larger than the fracture toughness value (K) of the ceramic substrate 20, the risk of large cracks occurring in the plug 55 is reduced.

[0074] The fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c is 2 MPa m 1 / 2 It is preferable that the viscosity is 3 MPa m or more. 1 / 2 More preferably, it is 4 MPa m 1 / 2Although no particular upper limit is set for the fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c, from the viewpoint of ease of manufacture, it is preferable that the KIC be 13 MPa m 1 / 2 It is preferable that the viscosity is 12 MPa m or less. 1 / 2 More preferably, it is 11 MPa m or less. 1 / 2 Therefore, the fracture toughness value (KIC) of the portion of the plug 55 that is made up of the dense body 55c is 2 to 13 MPa m 1 / 2 Preferably, the pressure is 3 to 12 MPa m 1 / 2 More preferably, it is 4 to 11 MPa m 1 / 2 It is even more preferable that:

[0075] The fracture toughness (KIC) of the portion of the plug 55 formed by the dense body 55c and the ceramic substrate 20 is measured in accordance with the SEPB method defined in JIS R1607:2015.

[0076] The material constituting the plug 55 can be an electrically insulating ceramic, and can contain, for example, one or more selected from aluminum oxide, aluminum nitride, and silicon dioxide. The plug 55 can also be made of only one or two selected from aluminum oxide, aluminum nitride, and silicon dioxide, excluding impurities. Quartz is preferable as the silicon dioxide. In particular, in order to control the fracture toughness value (KIC) of the portion of the plug 55 constituting the dense body 55c within the above-mentioned range, it is preferable to construct the portion of the plug 55 constituting the dense body 55c of the plug 55 from a ceramic material with high fracture toughness, such as alumina (aluminum oxide).

[0077] Furthermore, in order to maintain the fixing strength of the plug 55 embedded in the plug placement hole 50, it is preferable that the difference in thermal expansion coefficient between the plug 55 and the ceramic substrate 20 is small. For this reason, it is preferable that the material constituting the plug 55 and the material constituting the ceramic substrate 20 both contain one or more selected from aluminum oxide and aluminum nitride, and it is more preferable that the material compositions are the same.

[0078] The outer peripheral surface 55e of the plug 55 and the inner peripheral surface 50c of the plug arrangement hole 50 may be bonded via an adhesive, but it is preferable that they be directly fitted together without using an adhesive. Direct fitting between the two prevents a gap from forming between the plug 55 and the plug arrangement hole 50 due to deterioration of the adhesive caused by corrosion or erosion, etc. This has the advantage of suppressing discharge and detachment of the plug 55 caused by deterioration of the adhesive.

[0079] Furthermore, as shown in FIG. 2-1 , when observing a longitudinal cross section obtained by cutting the ceramic substrate 20 in the thickness direction, from the viewpoint of improving the fixing strength of the plug 55, it is preferable that the inner circumferential surface 50c of the plug arrangement hole 50 contacts the outer circumferential surface 55e of the plug 55 in a parallel positional relationship. In other words, the outer circumferential surface 55e of the plug 55 has the same inclination angle as the inner circumferential surface 50c of the plug arrangement hole 50. Therefore, in a preferred embodiment, the plug 55 has an outer shape that is the same shape as the plug arrangement hole 50 (e.g., a truncated cone or a truncated pyramid). This makes it possible to increase the area over which the inner circumferential surface 50c of the plug 55 contacts the outer circumferential surface 55e of the plug 55, thereby obtaining high fixing strength.

[0080] An example of a direct fitting method is to embed the plug 55 by press-fitting it into the plug arrangement hole 50. In this case, in order to obtain the desired fixing strength, it is preferable that the horizontal cross-sectional diameter of the plug 55 at any height position before press-fitting be slightly larger (for example, by about 5 to 20 μm in equivalent circle diameter) than the horizontal cross-sectional diameter of the plug arrangement hole 50 at the same height position. Another example of a direct fitting method is to thread a male thread portion provided on the outer peripheral surface 55 e of the plug 55 into a female thread portion provided on the inner peripheral surface 50 c of the plug arrangement hole 50.

[0081] A method for manufacturing such a dense body and the plug 55 having a gas flow path passing through the interior thereof includes, for example, a method of sintering a compact formed using additive manufacturing technology such as a 3D printer. Alternatively, the plug 55 may be formed by mold casting, the details of which are as described above.

[0082] The porosity of the plug can be controlled, for example, by adjusting the content of the pore-forming material in the raw material composition before firing the ceramics that constitute the plug. For example, the amount of the pore-forming material may be reduced or eliminated in order to densify the plug.

[0083] Other configurations of the semiconductor manufacturing equipment member 10 according to the second embodiment are the same as those described for the semiconductor manufacturing equipment member 10 according to the first embodiment, and therefore, redundant description will be omitted.

[0084] 3. Method of Using the Semiconductor Manufacturing Equipment Member Next, an example of how to use the semiconductor manufacturing equipment member 10 configured as described above will be described. First, with the semiconductor manufacturing equipment member 10 installed in a chamber (not shown), a wafer W is placed on the upper surface 21 of the ceramic substrate 20. Then, the chamber is depressurized using a vacuum pump to adjust the chamber to a predetermined degree of vacuum, and a voltage is applied to the electrodes 22 of the ceramic substrate 20 to generate an electrostatic adsorption force, thereby adsorbing and fixing the wafer W to the wafer-mounting surface (specifically, the upper surfaces of the seal bands 21 a and the protrusions 21 b).

[0085] Next, the chamber is filled with a reactive gas atmosphere at a predetermined pressure (e.g., several tens to several hundreds of Pa). In this state, a high-frequency voltage, such as an RF voltage, is applied between an upper electrode (not shown) installed in the ceiling of the chamber and the base plate 30 of the semiconductor manufacturing equipment member 10 to generate plasma. The surface of the wafer W is processed by the generated plasma. A coolant circulates through the coolant flow path 32 of the base plate 30. Backside gas is introduced into the gas supply path 60 from a gas cylinder (not shown) to increase the heat transfer efficiency between the wafer W and the ceramic substrate 20 and promote cooling. A thermally conductive gas (e.g., He gas) can be used as the backside gas. The backside gas is supplied to the multiple plug placement holes 50 through the gas supply path 60 and sealed in the space between the backside of the wafer W and the reference surface 21c of the wafer mounting surface. The presence of this backside gas efficiently conducts heat between the wafer W and the ceramic substrate 20.

[0086] Furthermore, the provision of the plug 55 in the plug arrangement hole 50 can suppress discharge within the plug arrangement hole 50. Without the plug 55, electrons generated as a result of ionization of gas molecules by application of RF voltage accelerate and collide with other gas molecules, causing glow discharge and eventually arc discharge. However, with the plug 55, the electrons strike the plug 55 before colliding with other gas molecules, suppressing discharge.

[0087] 4. Manufacturing Method of a Semiconductor Manufacturing Equipment Component Next, a manufacturing method of the semiconductor manufacturing equipment component 10 will be described with reference to FIG. 4. First, a ceramic substrate 20, a base plate 30, and a metal bonding material 90 are prepared ( FIG. 4A ). The ceramic substrate 20 can be manufactured by the following procedure. A circular ceramic sintered plate, which is the basis of the ceramic substrate 20, is produced by hot-pressing and firing a ceramic powder compact. The compact may be produced by stacking multiple tape compacts, by mold casting, or by compressing ceramic powder. The ceramic sintered plate incorporates an electrode 22. Next, a plug placement hole 50 is formed vertically through the ceramic sintered plate while avoiding the electrode 22. The plug placement hole 50 can be formed by machining. Furthermore, multiple protrusions 21b and a seal band 21a are formed on the top surface of the ceramic sintered plate by laser processing or the like. The timing for forming the plurality of protrusions 21b and the seal band 21a may be after the ceramic substrate 20 and the base plate 30 are bonded together.

[0088] The base plate 30 has a refrigerant flow path 32 and a gas hole 34. The gas hole 34 has a large diameter portion 34a facing the upper surface 31. The base plate 30 having the refrigerant flow path 32 can be manufactured, for example, by bonding multiple MMC plate members, in which grooves and holes corresponding to the refrigerant flow path 32 are formed by machining, using a method such as TCB (thermal compression bonding). The gas hole 34 can be formed by machining in the base plate 30 after the refrigerant flow path 32 is formed. The metal bonding material 90 has a through hole 92 at a position facing the large diameter portion 34a of the gas hole 34. The through hole 92 can be formed by machining.

[0089] Next, a metal bonding material 90 is sandwiched between the lower surface 23 of the ceramic substrate 20 and the upper surface 31 of the base plate 30 to form a laminate. It is preferable to stack the ceramic substrate 20 so that the plug placement hole 50, the through-hole 92 of the metal bonding material 90, and the gas hole 34 of the base plate 30 are coaxial. The laminate is then pressed and bonded at a temperature below the solidus temperature of the metal bonding material 90 (e.g., a temperature 20°C below the solidus temperature but below the solidus temperature), and then returned to room temperature (TCB). This results in the metal bonding material 90 and the through-hole 92 becoming the bonding layer 40 and the through-hole 42, respectively, resulting in a bonded structure in which the ceramic substrate 20 and the base plate 30 are bonded by the bonding layer 40 ( FIG. 4B ). It is preferable to use a metal bonding material 90 with a thickness of approximately 100 μm (e.g., 80 to 240 μm).

[0090] Next, a plug 55 having dimensions and a shape that can fit into the plug placement hole 50 is prepared ( FIG. 4B ). The height of the plug 55 is the same as the depth of the plug placement hole 50. Next, the plug 55 is press-fit into the plug placement hole 50 from the upper opening 50a toward the lower opening 50b of the ceramic substrate 20. Alternatively, a male thread portion may be formed on the outer peripheral surface 55e of the plug 55, which has been formed in advance by firing or the like, and a female thread portion may be formed on the inner peripheral surface 50c of the plug placement hole 50. The plug 55 may then be inserted into the plug placement hole 50 by threading the male thread portion of the plug 55 and the female thread portion of the plug placement hole 50. The semiconductor manufacturing equipment component 10 is then completed by appropriately performing processes such as adjusting the overall shape ( FIG. 4C ).

[0091] DESCRIPTION OF SYMBOLS 10: MEMBER FOR SEMICONDUCTOR MANUFACTURING APPARATUS 20: CERAMIC SUBSTRATE 21: UPPER SURFACE 21a: SEAL BAND 21b: PROJECTION 21c: REFERENCE SURFACE 21d: CONCENTRATION PORTION 22: ELECTRODE 23: LOWER SURFACE 30: BASE PLATE 31: UPPER SURFACE 32: REFRIGERANTE FLOWER PATH 33: LOWER SURFACE 34: GAS HOLE 34a: LARGE DIAMETER 40: JOINT LAYER 42: THROUGH HOLE 50: PLUG ARRANGEMENT HOLE 50a: UPPER OPENING 50b: LOWER OPENING 50c: INNER SURFACE 55: PLUG 55a: UPPER END SURFACE 55a1: UPPER END OPENING 55b: LOWER END SURFACE 55b1: LOWER END OPENING 55c: DENSITY BODY 55d: GAS FLOWER PATH 55d1: SURFACE 55e: OUTER SURFACE 55f: UPPER END 55f1: Side surface 55f2: Side opening 60: Gas supply path 64a: Ring portion 64b: Gas introduction portion 64c: Distribution portion 90: Metal bonding material 92: Through hole

Claims

1. A component for semiconductor manufacturing equipment comprising: a ceramic substrate having upper and lower surfaces for placing a wafer thereon; a plug placement hole that vertically penetrates the ceramic substrate; and a plug embedded in the plug placement hole, wherein the plug is made of a dense body and has an upper end surface exposed on the upper surface side, a lower end surface exposed on the lower surface side, and a gas flow path that extends from an upper end opening provided on the upper end surface to a lower end opening provided on the lower end surface, penetrating the interior of the dense body, and wherein a maximum height D1 in the vertical direction from the upper end opening to the surface of the gas flow path and a maximum height D2 in the vertical direction from the lower end opening to the surface of the gas flow path satisfy the relationship D1 < D2.

2. A member for semiconductor manufacturing equipment according to claim 1, which satisfies the relationship 0.1≦D1 / D2≦0.

9.

3. A member for semiconductor manufacturing equipment according to claim 1 or 2, wherein the maximum height D1 is 10 to 300 μm.

4. A member for semiconductor manufacturing equipment according to claim 1 or 2, wherein the maximum height D2 is 50 to 500 μm.

5. A component for semiconductor manufacturing equipment according to claim 1 or 2, wherein, taking coordinate axes in the vertical direction, the coordinate value at the top end surface of the plug is 0 and the coordinate value at the bottom end surface is H, the vertical height D of the gas flow path satisfies the relationship D≧1.5D1 at least within a range of coordinate values ​​from 0.5×H to 1.0×H.

6. A semiconductor manufacturing equipment member according to claim 5, wherein the vertical height D of the gas flow path satisfies the relationship D1≦D<1.5D1 at least in the range of coordinate values ​​from 0 to less than 0.1×H.

7. A member for semiconductor manufacturing equipment according to claim 1 or 2, wherein the plug has a plurality of the gas flow paths, and all of the plurality of gas flow paths satisfy the relationship D1<D2.

8. A member for semiconductor manufacturing equipment according to claim 1 or 2, wherein the fracture toughness value (KIC) of the portion of the plug made of the dense body is greater than the fracture toughness value (KIC) of the ceramic substrate.

9. A component for semiconductor manufacturing equipment comprising: a ceramic substrate having upper and lower surfaces for placing a wafer thereon; a plug placement hole that penetrates the ceramic substrate in the vertical direction; and a plug embedded in the plug placement hole, wherein the plug is made of a dense body and has an upper end portion having an upper end surface exposed on the upper surface side, a lower end surface exposed on the lower surface side, and a gas flow path that extends from a side opening provided on a side surface of the upper end portion through the dense body to a lower end opening provided on the lower end surface.

10. A semiconductor manufacturing equipment member according to claim 9, wherein a recess is formed in the top surface for placing a wafer, and the top end of the plug protrudes from the bottom surface of the recess so as to expose the side opening.

11. A member for semiconductor manufacturing equipment according to claim 9 or 10, wherein the height D of the gas flow path in the vertical direction is 10 to 300 μm.

12. A member for semiconductor manufacturing equipment according to claim 9 or 10, wherein the fracture toughness value (KIC) of the portion of the plug made of the dense body is greater than the fracture toughness value (KIC) of the ceramic substrate.

13. A component for semiconductor manufacturing equipment as described in claim 9 or 10, wherein the plug has a plurality of gas flow paths, each of which extends from a side opening provided on a side surface of the upper end portion, through the interior of the dense body, to a lower end opening provided on the lower end surface.

Images