Semiconductor substrate processing base and substrate holding member

Abstract

To provide a semiconductor substrate processing base and substrate holding member that facilitates handling, while minimizing the CTE difference with the electrode embedding member bonded to the upper surface of the ceramic substrate and suppressing warping and delamination of the electrode embedding member.SOLUTION: A semiconductor substrate processing base 100 comprises a ceramic base material 110 in which a portion of a media flow path 118 having an opening 119 is formed and which is formed by a ceramic sintered body, and a metal base material 120 for blocking the opening 119 of the media flow path 118.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor substrate processing base and a substrate holding member. [Background technology]

[0002] In the semiconductor manufacturing process, ceramic electrostatic chucks and heater plates have been used to process substrates (wafers) at a specified temperature, and these have been fixed onto an aluminum alloy base with a media flow path.

[0003] Recently, semiconductor manufacturing processes have become more power-hungry, resulting in a significant increase in the amount of heat passing through the substrate. This has resulted in stress acting between the electrostatic chuck and the base due to differences in thermal expansion caused by differences in CTE between the ceramic electrostatic chuck and the Al alloy base. This has led to uneven heat transfer and warping due to poor adhesion between the two, hindering the process. Therefore, ceramic bases are being considered as an alternative to Al alloys.

[0004] Patent Document 1 discloses a substrate support part that includes an electrostatic chuck made of ceramics that holds a substrate to be processed by electrostatic attraction, a base that supports the electrostatic chuck, and a flow path through which a heat exchange medium flows, the upper surface of the flow path being made of ceramics.

[0005] Patent Document 2 discloses a flow path member that includes a main body made of a ceramic sintered body with a flow path through which a fluid flows formed therein, the main body having a convex portion made of a part of the ceramic sintered body on the inner wall of the flow path, the convex portion having an elongated shape along the longitudinal direction of the flow path, the flow path having an elongated shape in a plan view and having a curved portion that is bent at least in a part thereof, and the main body having a plurality of the convex portions spaced apart from each other along the longitudinal direction of the flow path at the curved portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-003003 [Patent Document 2] Patent No. 6092857 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Document 1 describes a concern that the elimination of an adhesive layer as a buffer to absorb the thermal expansion difference between the ceramic electrostatic chuck and the aluminum base may increase the likelihood of peeling at the bonding surface between the electrostatic chuck and the base. To avoid this, the area of ​​the bonding surface between the electrostatic chuck and the base is minimized, preventing peeling. It also describes that the thermal expansion difference between the ceramic electrostatic chuck and the aluminum base is absorbed by deformation of the flow path, preventing peeling between the electrostatic chuck and the base even when the substrate support is controlled to a high or low temperature. However, simply using the upper surface of the flow path as the lower surface of the electrostatic chuck may result in insufficient heat exchange with the heat exchange medium flowing through the flow path due to the small contact area between the electrostatic chuck and the base. Furthermore, forming a flow path on the lower surface of an electrostatic chuck with an embedded electrode complicates the manufacturing process and increases costs.

[0008] In Patent Document 2, the process of stacking two molded bodies and co-firing them is involved, which increases the cost of producing a hollow structure. In addition, the base is made entirely of ceramics, which is a brittle material and therefore difficult to handle.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide a semiconductor substrate processing base and a substrate holding member that can reduce the CTE difference with the electrode-embedded member bonded to the upper surface of the ceramic base, suppress warping and peeling of the electrode-embedded member, and are easy to handle. [Means for solving the problem]

[0010] (1) In order to achieve the above object, the present invention provides the following means: That is, a semiconductor substrate processing base according to an application example of the present invention is a semiconductor substrate processing base comprising: a ceramic base formed of a sintered ceramic body, on which a portion of a media flow path having an opening is formed; and a metal base that closes the opening of the media flow path.

[0011] This reduces the difference in CTE between the ceramic substrate and the electrode-embedding member bonded to the upper surface of the ceramic substrate, thereby preventing warping and peeling of the electrode-embedding member. Furthermore, various combinations of ceramic substrates and metal substrates can be selected, allowing the hollow structure of the substrate processing base to be manufactured at low cost. Furthermore, the substrate processing base is easier to handle than a substrate processing base made entirely of a ceramic sintered body.

[0012] (2) In the semiconductor substrate processing base of the application example (1) above, the ceramic base and the metal base are bonded together with a bonding material, which allows the ceramic base and the metal base to be easily bonded together.

[0013] (3) In the semiconductor substrate processing base of the application example (1) above, the ceramic substrate and the metal substrate are fastened together by a fastening member, which allows easy fastening even when the combination of ceramic substrates and metal substrates is difficult to join using a bonding material or direct bonding, thereby increasing the degree of freedom in combining ceramic substrates and metal substrates.

[0014] (4) In the semiconductor substrate processing base of the application example (1) above, the ceramic substrate and the metal substrate are directly bonded to each other, which allows the ceramic substrate and the metal substrate to be bonded without using a bonding material or fastening member, and can be used in high-temperature applications.

[0015] (5) In addition, in the semiconductor substrate processing base according to any one of the application examples (1) to (4), the ceramic sintered body contains SiC. This reduces the difference in CTE with the electrode-embedded member, increases thermal conductivity, and improves cooling capacity. Furthermore, a water-based medium with a high heat transfer coefficient can be used.

[0016] (6) Furthermore, a substrate holding member according to an application example of the present invention is characterized by comprising: a semiconductor substrate processing base according to any one of the application examples (1) to (5) above; and an electrode-embedded member formed of a second ceramic sintered body and joined to one main surface of the semiconductor substrate processing base on the ceramic member side.

[0017] This reduces the difference in CTE between the ceramic substrate and the electrode-embedded member, preventing warping and peeling of the electrode-embedded member. Furthermore, a wide range of combinations of ceramic substrates and metal substrates can be selected, allowing for the hollow structure of the substrate processing base to be manufactured at low cost. Furthermore, the substrate processing base is easier to handle than a substrate holding member that uses a substrate processing base made entirely of sintered ceramics.

[0018] (7) In the substrate holding member according to the application example of (6) above, the difference in CTE between the ceramic sintered body and the second ceramic sintered body is 4.0 ppm / K or less, which further suppresses warping and peeling of the electrode-embedded member. [Effects of the Invention]

[0019] The semiconductor substrate processing base or substrate holding member of the present invention can reduce the difference in CTE between the ceramic substrate and the electrode-embedded member bonded to the upper surface of the ceramic substrate, thereby suppressing warping and peeling of the electrode-embedded member and making it easier to handle than a base formed entirely of a ceramic sintered body. [Brief explanation of the drawings]

[0020] [Figure 1]1 is a schematic cross-sectional view showing an example of a semiconductor substrate processing base according to an embodiment of the present invention. [Figure 2] FIG. 10 is a schematic cross-sectional view showing a modified example of the semiconductor substrate processing base according to the embodiment of the present invention. [Figure 3] FIG. 10 is a schematic cross-sectional view showing a modified example of the semiconductor substrate processing base according to the embodiment of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing an example of a substrate holding member according to an embodiment of the present invention. [Figure 5] 10 is a table showing the configuration of the substrate holding members of Examples and Comparative Examples, the presence or absence of water leakage, and evaluation of changes in flatness. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, an embodiment of the present invention will be described with reference to the drawings. To facilitate understanding of the description, the same reference numerals are used to designate the same components in the drawings, and duplicated descriptions will be omitted. Note that in the configuration diagrams, the size of each component is shown conceptually and does not necessarily represent the actual dimensional ratio.

[0022] [Embodiment] (Configuration of semiconductor substrate processing base) A semiconductor substrate processing base according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of a semiconductor substrate processing base according to an embodiment of the present invention. The semiconductor substrate processing base 100 according to an embodiment of the present invention includes a ceramic base 110 and a metal base 120.

[0023] The ceramic substrate 110 is made of a ceramic sintered body. This allows the ceramic substrate 110 to be provided with a media flow path 118 and its openings 119. Furthermore, the CTE difference between the ceramic sintered body forming the electrode-embedding member 210 can be reduced, thereby suppressing warping and peeling of the electrode-embedding member 210. Furthermore, the CTE difference between the ceramic sintered body forming the ceramic substrate 110 and the second ceramic sintered body forming the electrode-embedding member 210 is preferably 4.0 ppm / K or less. This further suppresses warping and peeling of the electrode-embedding member 210. The CTE difference is defined as the difference between the larger value and the smaller value. The ceramic substrate 110 can be formed, for example, from ceramics containing SiC or ceramics containing Al2O3. The ceramic substrate 110 is formed, for example, in the shape of a generally flat plate with a diameter of 200 mm or more and a thickness of 10 to 50 mm. The ceramic substrate 110 may have various shapes, such as a generally circular plate, a polygonal plate, or an elliptical plate.

[0024] The ceramic base 110 is preferably made of ceramics with a thermal conductivity of 70 W / mK or more. This allows the ceramic base 110 itself to have high thermal conductivity, making it suitable for use as a cooling ceramic base 110. As a ceramic with a thermal conductivity of 70 W / mK or more, for example, ceramics containing SiC can be used.

[0025] The ceramic substrate 110 is preferably formed of a ceramic sintered body whose main component is SiC. "Mainly composed of SiC" refers to a ceramic sintered body containing 50 wt% or more of SiC, or a ceramic sintered body containing SiC and having a thermal conductivity of 70 W / mK or more. SiC can be suitably used as the ceramic substrate 110 because it can reduce the difference in CTE with the electrode-embedded member 210 formed of a ceramic sintered body (described later), and has high thermal conductivity and can enhance cooling capacity. Furthermore, SiC can be used with a water-based medium with a high heat transfer coefficient.

[0026] The ceramic substrate 110 has at least a portion of a media flow path 118 and an opening 119 that open to one main surface 112 of the ceramic substrate 110, to which an electrode-embedded member 210 (described later) is bonded, and the other main surface 116 faces the other main surface 112. The opening 119 is closed by the metal substrate 120, thereby forming the media flow path 118. This allows the medium in the media flow path 118 to absorb heat from the substrate.

[0027] As described above, the ceramic base 110 has openings 119 formed in the other main surface 116, but no openings formed in the one main surface 112. This shape of the ceramic base 110 allows the electrode-embedding member 210 and the one main surface 112 of the ceramic base 110 to be bonded, for example, over the entire surface. As a result, a uniform heat flow is transferred from the lower surface 214 of the electrode-embedding member 210 (described later) to the one main surface 112 of the ceramic base 110, resulting in a uniform temperature distribution on the substrate-mounting surface 212 of the electrode-embedding member 210.

[0028] The width of the medium flow channel 118 formed in the ceramic substrate 110 is preferably 1 mm or more and 60 mm or less. The cross-sectional shape of the medium flow channel 118 is not limited to a rectangle, and may be any manufacturable shape, such as a semicircular shape or a stepped shape. The medium flow channel 118 preferably uses a low-temperature chiller for circulation. Therefore, the medium flow channel 118 is preferably provided with an inlet for introducing the chiller and an outlet for discharging the chiller. The inlet and outlet may be provided in either the ceramic substrate 110 or the metal substrate 120, but providing them in the metal substrate 120 is preferable for simplicity. The medium flow channel 118 is connected to a chiller unit provided outside a vacuum chamber or the like in which the semiconductor substrate processing base 100 is installed.

[0029] The media flow path 118 may have a shape, as viewed from above through the ceramic substrate 110, that is, a substantially circular or spiral shape centered at the center of the ceramic substrate 110. A substantially circular shape includes a shape in which some of the arcs of the circular ring are not connected, and a normal circular shape. A substantially spiral shape includes a shape in which the circumferential arc shapes are connected with their curvature changing in the radial direction from the center of the ceramic substrate 110.

[0030] The medium flow channels 118 may be arranged concentrically around the center of the ceramic substrate 110 when viewed see-through from above. The concentrically arranged, approximately annular medium flow channels 118 may be double, triple, or more. The concentrically arranged, approximately annular medium flow channels 118 may be connected inside the ceramic substrate 110, or each may have an inlet and an outlet formed therein.

[0031] The width of the gap between adjacent media flow channels 118 (the width of the ceramic substrate 110 present in the gap between adjacent media flow channels 118) is preferably 2 mm or more. Furthermore, the width of the gap between adjacent media flow channels 118 is preferably 25% or more of the width of the media flow channel 118. This allows the strength of the ceramic substrate 110 to be maintained even when a media flow channel 118 is formed on the other main surface 116 of the ceramic substrate 110.

[0032] The medium flow passage 118 may include a linear shape. Alternatively, some of the substantially circular, spiral, or linear medium flow passages 118 may be combined. The substantially circular, spiral, or linear medium flow passages 118 may be connected to each other.

[0033] The medium flow channel 118 may be formed by combining a groove having an opening 119 in the ceramic substrate 110 and a groove having an opening in the upper surface 124 of the metal substrate 120. This can further improve the cooling efficiency. When the medium flow channel 118 is formed in the metal substrate 120, the shape, spacing width, etc. of the medium flow channel 118 are the same as when the medium flow channel 118 is formed in the ceramic substrate 110. Note that FIG. 1 illustrates the case where the medium flow channel 118 is formed only in the ceramic substrate 110.

[0034] The thickness of the metal base 120 is preferably 5 mm or more and 20 mm or less, and more preferably 7 mm or more and 15 mm or less. This provides sufficient strength to the underside of the semiconductor substrate processing base 100, making it easier to handle than a substrate processing base made entirely of a ceramic sintered body. In other words, even if an unintended external force is applied to the semiconductor substrate processing base 100, the risk of defects occurring in the ceramic base 110 can be reduced.

[0035] The metal substrate 120 can be made of a general-purpose metal material, such as stainless steel, Al, Ti, Mo, W, or alloys thereof. These metals are readily available and easy to process, making them suitable for use as the metal substrate 120. The metal substrate 120, like the ceramic substrate 110, is formed in a generally flat plate shape with a diameter of 200 mm or more. Corresponding to the ceramic substrate 110, the metal substrate 120 may have various shapes, such as a generally circular plate, a polygonal plate, or an elliptical plate.

[0036] The metal base 120 may be an Al alloy. The Al alloy has high thermal conductivity, which can further improve cooling efficiency. In addition, the Al alloy is cost-effective and easy to process, making it suitable as a material for the metal base 120.

[0037] The metal base 120 may be a Ti alloy. Since the Ti alloy has a CTE close to that of the material of the ceramic base 110 to be joined, warping or peeling of the ceramic base 110 from the metal base 120 can be suppressed. In addition, since the Ti alloy has excellent strength, it is suitable as a material for the metal base 120 as a reinforcing material for the semiconductor substrate processing base 100.

[0038] The metal substrate 120 may be made of Mo, W, or an alloy thereof. When the ceramic substrate 110 is made of a ceramic sintered body mainly composed of SiC or AlN, and the metal substrate 120 is made of Mo, W, or an alloy thereof, the CTEs are close, allowing the metal substrate 120 and the ceramic substrate 110 to be directly bonded. As a result, this is suitable as a material for the metal substrate 120 because it can be used in high-temperature applications.

[0039] In this way, various combinations of the ceramic base 110 and the metal base 120 can be selected depending on the use environment and manufacturing conditions of the semiconductor substrate processing base 100. This increases the degree of freedom in designing the semiconductor substrate processing base 100.

[0040] The ceramic substrate 110 and the metal substrate 120 may be bonded to each other at the other main surface 116 of the ceramic substrate 110 and the top surface 124 of the metal substrate 120 via a first bonding layer 130, which will be described later. This allows the metal substrate 120 to close an opening 119 that opens to the other main surface 116 of the ceramic substrate 110, thereby forming a media flow path 118. Note that the media flow path 118 may be formed by providing a groove having an opening 119 in the ceramic substrate 110 and simultaneously providing a groove having an opening in the top surface 124 of the metal substrate 120, and then bonding these together via the first bonding layer 130.

[0041] The first bonding layer 130 is made of a bonding material and is formed on at least a portion of the upper surface 124 of the metal substrate 120. The first bonding layer 130 bonds the metal substrate 120 and the ceramic substrate 110. The first bonding layer 130 is preferably formed of a bonding material such as an organic adhesive containing a resin material as a main component. Various materials, such as silicone resin, fluororesin, acrylic resin, or epoxy resin, can be used as the resin-based adhesive. Among these, silicone resin or epoxy resin is preferably used. The first bonding layer 130 may be formed of a bonding material such as a brazing material containing a metal such as Al, Ag, Au, or Ni, or an inorganic adhesive. Note that prior to brazing, pretreatment such as forming a base (e.g., forming a thin film of Cr or Ti) may be performed on the surface of the ceramic substrate 110 or the metal substrate 120.

[0042] In this way, by bonding the ceramic base 110 and the metal base 120 with a bonding material, the ceramic base 110 and the metal base 120 can be easily bonded to each other. Note that the bonding between the ceramic base 110 and the metal base 120 is not limited to bonding via the first bonding layer 130, and they may be fastened or bonded to each other by a fastening member 140 (described later) or by direct bonding.

[0043] FIG. 2 is a schematic cross-sectional view illustrating a modified example of a semiconductor substrate processing base according to an embodiment of the present invention. As shown in FIG. 2, instead of bonding using a first bonding layer 130, the metal substrate 120 and the ceramic substrate 110 may be fastened together using a fastening member 140. The fastening member 140 may be, for example, a bolt, a screw, a clamp, or the like. For example, the ceramic substrate 110 may have a through-hole 128 formed perpendicular to the other main surface 116 of the ceramic substrate 110, and a hole 126 formed in the upper surface 124 of the metal substrate 120. The fastening member 140 may be inserted through the through-hole 128 and threadedly engage with the hole 126 to fasten the ceramic substrate 110 and the metal substrate 120 together. This facilitates fastening even when the ceramic substrate 110 and the metal substrate 120 are difficult to bond using a bonding material or direct bonding, thereby increasing the flexibility of the combination of the ceramic substrate 110 and the metal substrate 120. Alternatively, holes 126 may be provided in the other main surface 116 of the ceramic base 110 , and through-holes 128 perpendicular to the upper surface 124 of the metal base 120 may be provided in the metal base 120 .

[0044] When the ceramic substrate 110 and the metal substrate 120 are fastened together by the fastening member 140, it is preferable to place a sealing member 150 in a groove provided in the upper surface 124 of the metal substrate 120 for sealing. This reduces leakage of the medium from the gap between the ceramic substrate 110 and the metal substrate 120. The sealing member 150 can be formed, for example, from a resin O-ring, a metal O-ring, a C-ring, or various metal seals. The groove in which the sealing member 150 is placed may also be provided on the other main surface 116 of the ceramic substrate 110.

[0045] 3 is a schematic cross-sectional view showing a modified example of a semiconductor substrate processing base according to an embodiment of the present invention. As shown in FIG. 3, instead of bonding using a first bonding layer 130, the metal substrate 120 and the ceramic substrate 110 may be bonded by direct bonding. When the ceramic substrate 110 is formed of a ceramic sintered body mainly composed of SiC or AlN, the ceramic substrate 110 and the metal substrate 120 can be directly bonded by using W, Mo, or an alloy thereof as the metal substrate 120. This allows the ceramic substrate 110 and the metal substrate 120 to be bonded without using a bonding material or fastening member, and can be used in high-temperature applications.

[0046] In this way, the ceramic substrate 110 and the metal substrate 120 can be bonded together by any bonding method, such as a bonding material, a fastening member, or direct bonding. In particular, when AlN and Mo are combined, or when SiC and W are combined, the CTEs of the respective materials are close to each other, allowing for favorable bonding. This allows the metal substrate 120 to close the opening 119 provided on the other main surface 116 of the ceramic substrate 110, thereby forming the medium flow path 118, thereby enabling the hollow structure of the semiconductor substrate processing base 100 to be manufactured at low cost.

[0047] (Configuration of substrate holding member) Next, a substrate holding member according to an embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view showing an example of a substrate holding member according to an embodiment of the present invention. A substrate holding member 200 according to an embodiment of the present invention includes a semiconductor substrate processing base 100 and an electrode-embedded member 210. The semiconductor substrate processing base 100 is the same as described above.

[0048] The electrode-embedding member 210 may be bonded to one main surface 112 of the ceramic base 110 via a second bonding layer 220, which will be described later. In this case, it is preferable that the electrode-embedding member 210 be bonded to the entire main surface 112 of the ceramic base 110 or the entire lower surface 214 of the electrode-embedding member 210 via the second bonding layer 220. This allows a uniform heat flow to be transferred from the lower surface 214 of the electrode-embedding member 210 to the one main surface 112 of the ceramic base 110, thereby making the temperature distribution on the substrate-mounting surface 212 of the electrode-embedding member 210 uniform. Note that the bonding between the substrate holding member 200 and the ceramic base 110 is not limited to bonding via the second bonding layer 220, and they may be fastened using a fastening member.

[0049] The electrode-embedding member 210 has a substrate-mounting surface 212. An electrode 218 is embedded in the electrode-embedding member 210. The electrode 218 may have various shapes, such as a mesh shape or a foil shape. The electrode 218 may also be made of various materials, such as Mo or W. The electrode 218 embedded in the electrode-embedding member 210 may function as an electrostatic attraction electrode, a heater electrode, a high-frequency electrode, or the like. Two or more types of electrodes 218 may be embedded in the electrode-embedding member 210. Power may be supplied to the electrode 218 via a terminal (not shown).

[0050] The electrode-embedding member 210 is preferably formed of an insulating ceramic sintered body (second ceramic sintered body). This allows the electrode-embedding member 210, which is joined to one main surface 112 of the ceramic base 110, to function as an insulating member that has electrical insulation, is dense, and has high thermal conductivity. In addition, the electrode 218 can be easily embedded. The thickness of the electrode-embedding member 210 is preferably 1 mm or more and 20 mm or less.

[0051] The electrode-embedding member 210 is preferably formed from a ceramic primarily composed of AlN, Al2O3, or Y2O3, and more preferably AlN, which has excellent thermal conductivity. "Mainly composed" refers to a ceramic containing 50 wt% or more of this compound. It is also preferable to select a combination of materials for the ceramic substrate 110 and the electrode-embedding member 210 such that the difference in CTE between the ceramic sintered compact forming the ceramic substrate 110 and the second ceramic sintered compact forming the electrode-embedding member 210 is 4.0 ppm / K or less. This further reduces warping and peeling of the electrode-embedding member.

[0052] The second bonding layer 220 is made of a bonding material and is formed on one main surface 112 of the ceramic substrate 110. The second bonding layer 220 bonds the ceramic substrate 110 and the electrode-embedded member 210. The second bonding layer 220 is preferably formed of a bonding material such as an organic adhesive containing a resin material as a main component. Various materials can be used as the resin-based adhesive, such as silicone resin, fluororesin, acrylic resin, or epoxy resin. Among these, silicone resin or epoxy resin is preferably used. The second bonding layer 220 may be formed of a bonding material such as a brazing material containing metals such as In and Al, or an inorganic adhesive. Note that prior to brazing, pretreatment such as the formation of a base layer (e.g., the formation of a thin Cr or Ti film) may be performed on the surface of the ceramic substrate 110 or the electrode-embedded member 210.

[0053] When the second bonding layer 220 is formed using an organic adhesive, it is preferable that a filler be added to the adhesive to increase thermal conductivity. The thermal conductivity of the second bonding layer 220 is preferably 0.4 W / mK or higher. Furthermore, the elongation of the second bonding layer 220 is preferably 100% or higher. The thickness of the second bonding layer 220 is preferably 500 μm or less, and more preferably 100 μm or less. This allows for a large amount of heat to be transferred. If the thickness is greater than 500 μm, the thermal resistance of the second bonding layer 220 may become significant even when a highly thermally conductive metal or adhesive is used. The lower limit of the thickness of the second bonding layer 220 can be, for example, 10 μm or more. This is because thicknesses thinner than this make it difficult to control the thickness.

[0054] The ceramic base 110 and the electrode-embedded member 210 may be fastened together by a fastening member instead of the bonding by the second bonding layer 220. The fastening member may be, for example, a bolt, a screw, a clamp, or the like.

[0055] When fastening the ceramic base 110 and the electrode-embedding member 210 together, it is preferable to place a sealing member in a groove provided on one main surface 112 of the ceramic base 110 to seal them. This allows for easy replacement of the electrode-embedding member 210 that has reached the end of its life after long-term use, and allows the substrate holding member 200 to be recycled at low cost. The sealing member can be formed, for example, from a resin O-ring, a metal O-ring, a C-ring, or various metal seals. The groove in which the sealing member is placed may be provided on the underside 214 of the electrode-embedding member 210.

[0056] [Method of manufacturing substrate holding member] Next, an example of a method for manufacturing a substrate holding member according to an embodiment of the present invention will be described. The method for manufacturing a substrate holding member according to an embodiment of the present invention includes the steps of preparing a ceramic base, preparing a metal base, joining or fastening the ceramic base and the metal base, preparing an electrode-embedding member, and joining or fastening the semiconductor substrate processing base and the electrode-embedding member.

[0057] Below, as specific examples, we will explain a method for manufacturing a ceramic member when the ceramic base is formed of a SiC ceramic sintered body, the metal base is formed of an Al alloy, and the electrode-embedded member is formed of an AlN ceramic sintered body, a method for manufacturing an electrode-embedded member, and a method for manufacturing a substrate holding member that includes a method for joining or fastening a semiconductor substrate processing base and an electrode-embedded member.

[0058] (Method for manufacturing ceramic substrate) The ceramic substrate according to the embodiment of the present invention is fabricated, for example, by a molded body hot pressing method described below. Note that the method for fabricating the base is not limited to this method, and may be, for example, a powder hot pressing method or a conventional green sheet lamination method. The powder hot pressing method is a method in which ceramic raw material powder and predetermined heating resistors and electrodes are alternately stacked to embed the heating resistors and electrodes inside the ceramic, and then the resultant is uniaxially hot-press fired.

[0059] The manufacturing method of a ceramic substrate using a molded body hot pressing method according to an embodiment of the present invention includes a ceramic molded body forming step, a ceramic degreased body preparing step, a firing step, a ceramic sintered body processing step, a metal substrate processing step, and a joining or fastening step. Note that although the following manufacturing method describes a manufacturing method in which a media flow channel is formed only in the ceramic substrate, a media flow channel may be formed in both the ceramic substrate and the metal substrate.

[0060] In the ceramic green body forming process, one or more ceramic green bodies are formed from ceramic raw material powder mainly composed of, for example, SiC (silicon carbide). Sintering aids and additives may be added as needed. For example, sintering aids such as B4C and C, and additives such as binders, plasticizers, and dispersants are appropriately added to and mixed with the SiC ceramic raw material powder to prepare a slurry, which is then granulated by a method such as spray drying. The additive may be a nitride, carbide, or boride of a metal selected from Groups 4 to 6 of the periodic table. These components may be added to adjust the difference in linear expansion coefficient between the granulated powder and the electrode-embedded member. The granulated powder is then pressure-molded to form multiple ceramic green bodies.

[0061] The SiC ceramic raw material powder is preferably highly pure, preferably 96% or more, more preferably 99% or more, and even more preferably 99.9% or more. The average particle size of the SiC ceramic raw material powder is preferably 0.1 μm or more and 1.0 μm or less.

[0062] The mixing method may be either wet or dry, and a mixer such as a ball mill or a vibration mill may be used. The molding method may be a known method such as uniaxial pressing or cold isostatic pressing (CIP). The method for forming the ceramic compact is not limited to pressure molding; for example, green sheet lamination or slip casting may also be used. The ceramic compact can be manufactured by appropriately degreasing or further calcining the resulting product.

[0063] After molding, the ceramic molded body may be machined to adjust the shape of the molded body. The machining may be performed after degreasing.

[0064] In the ceramic degreased body production process, one or more ceramic molded bodies are degreased at a predetermined temperature or higher for a predetermined time or longer to produce multiple ceramic degreased bodies. The ceramic molded bodies are heat-treated, for example, at a temperature of 500°C to 900°C to produce ceramic degreased bodies. The degreasing time is preferably 1 hour to 120 hours. An atmospheric or nitrogen atmosphere furnace can be used for degreasing, but an atmospheric furnace is preferred to remove organic components from the binder.

[0065] In the firing process, the formed ceramic degreased body is uniaxially pressurized or atmospherically fired to form one or more ceramic sintered bodies. When uniaxially pressurized firing is performed, the pressure is preferably 4 MPa or more. The firing temperature is preferably 2000°C or more and 2200°C or less. The firing time is preferably 1 hour or more and 12 hours or less, and more preferably 1 hour or more and 5 hours or less. The firing atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. Alternatively, the vacuum atmosphere may be followed by an inert gas atmosphere. As a result, one or more ceramic degreased bodies are sintered to form one or more SiC ceramic sintered bodies.

[0066] In the ceramic sintering process, the SiC ceramic sintered body is subjected to necessary processing to form a ceramic substrate. For example, a groove with an opening that will become a media flow path after bonding is formed in the SiC ceramic sintered body. At this time, the media flow path may be formed by covering the opening formed in the ceramic substrate with a metal substrate. Alternatively, the media flow path may be formed by combining openings formed in the ceramic substrate and the metal substrate. This method allows for the formation of media flow paths of various shapes. Furthermore, if terminals are used for electrical connection of the electrode-embedded member, through holes or the like are drilled for connecting the terminals. The drilling of through holes or the like for connecting the terminals may be performed after the bonding process.

[0067] When a fastening member is used in the joining or fastening process, a through-hole or hole for inserting the fastening member is drilled in the ceramic substrate. When a groove for disposing a sealing member is formed in the ceramic substrate, the groove is formed on the other main surface of the ceramic substrate. When a groove for disposing a sealing member is formed in the metal substrate, it is not necessary to form a groove in the ceramic substrate.

[0068] When a fastening member is used in the joining or fastening process with the electrode-embedded member, similar processing is performed on one main surface to form through holes, holes, and grooves for arranging sealing members used for fastening with the electrode-embedded member.

[0069] In the metal substrate processing step, the outer shape of the metal substrate is processed. When forming a media flow path in the metal substrate, a groove having an opening that will become the media flow path after bonding is formed on the upper surface of the metal substrate. Furthermore, when terminals are used for electrical connection of the electrode-embedded member, through holes or the like for connecting the terminals are drilled. The drilling of through holes or the like for connecting the terminals may be performed after the bonding step.

[0070] When a fastening member is used in the joining or fastening process, a through-hole or hole for inserting the fastening member is drilled in the metal substrate. When a groove for disposing a sealing member is formed in the metal substrate, the groove is formed on the upper surface of the metal substrate. When a groove for disposing a sealing member is formed in the ceramic substrate, the groove does not need to be formed in the metal substrate.

[0071] In the bonding or fastening step, the ceramic substrate and the metal substrate are bonded or fastened to each other to produce a semiconductor substrate processing base. The bonding or fastening can be performed using a bonding method that uses a bonding material, a fastening member, or a bonding method that does not use a bonding material.

[0072] First, a bonding method using a bonding material will be described. First, a bonding material is prepared and applied to at least one of the end faces of the ceramic substrate or the metal substrate to be bonded. The end faces of the ceramic substrate and the metal substrate to be bonded are preferably polished to a surface roughness Ra of 1.6 μm or less, and more preferably to 0.4 μm or less. The thickness of the applied bonding material is preferably 10 μm or more and 100 μm or less.

[0073] The bonding material may be any material capable of bonding the ceramic substrate and the metal substrate. For example, it is preferably formed from an organic adhesive containing a resin material as a main component. Various materials can be used as the organic adhesive, such as silicone resin, fluororesin, acrylic resin, or epoxy resin. Among these, it is preferable to use silicone resin or epoxy resin.

[0074] The bonding material may be a brazing material containing a metal such as In, Al, Au, or Ag, or a brazing material containing these and an active metal such as Ti, Hf, or Zr. Metal foil may also be used as the brazing material. If necessary, the bonding surfaces may be metallized with Ti, Cr, Ni, Cu, or the like.

[0075] Next, the ceramic substrate and the metal substrate are placed and heated while applying pressure perpendicular to the upper surface. The pressure is preferably 5 kPa or more. The heating temperature is preferably the melting point or glass transition point of the bonding material. The heating time is preferably 0.1 to 5 hours. The heating atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. This bonds the ceramic substrate and the metal material to form a semiconductor substrate processing base having a media flow path therein.

[0076] Next, a fastening method using a fastening member will be described. First, a ceramic substrate and a metal substrate are placed. In the aforementioned ceramic sintered body processing step and metal substrate processing step, through holes or holes drilled in the ceramic substrate or metal substrate, respectively, are used to fasten the ceramic substrate and metal substrate by inserting a fastening member into the through holes and screwing it into the holes. In this way, the ceramic substrate and metal material are fastened together to form a semiconductor substrate processing base having a media flow path therein.

[0077] When using a fastening member, it is preferable to place a sealing member in a groove formed in either the ceramic substrate or the metal material in the aforementioned ceramic sintered body processing step and metal substrate processing step. The sealing member can be, for example, a resin O-ring, a metal O-ring, a C-ring, or various metal seals.

[0078] Next, direct bonding will be described as a bonding method that does not use a bonding material. When the ceramic substrate is formed of a ceramic sintered body whose main components are SiC or AlN, the ceramic substrate and metal member can be directly bonded by using Mo, W, or alloys thereof as the metal member. The end face of the ceramic substrate on the bonding side preferably has a surface roughness Ra of 1.6 μm or less, and is more preferably polished to 0.4 μm or less. The same applies to the end face of the metal substrate on the bonding side.

[0079] Next, the ceramic substrate and the metal substrate are placed and heated while applying pressure perpendicular to the upper surface. The pressure is preferably 5 kPa or more. The heating temperature is preferably 1500°C or more and 1800°C or less. The heating time is preferably 0.5 hours or more and 5 hours or less. The heating atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. This allows the ceramic substrate and the metal substrate to be bonded together to form a semiconductor substrate processing base having a media flow path therein.

[0080] (Method of manufacturing electrode-embedded member) When the electrode-embedded member of the substrate holder according to the embodiment of the present invention is formed of a ceramic sintered body, it is produced, for example, by a molded body hot pressing method described below. Note that the method for producing the substrate holder is not limited to this method, and may be, for example, a powder hot pressing method or a conventional green sheet lamination method.

[0081] The method for manufacturing an electrode-embedded member of a substrate holder according to an embodiment of the present invention by a molded body hot pressing method includes a ceramic molded body forming step, a ceramic degreased body preparing step, a firing step, and a ceramic sintered body processing step.

[0082] In the ceramic green body forming process, multiple ceramic green bodies are formed from ceramic raw material powder containing, for example, aluminum nitride (AlN) as the main component. Sintering aids may be added as needed. For example, AlN ceramic raw material powder is mixed with an appropriate amount of additives, such as a sintering aid Y2O3, a binder, a plasticizer, and a dispersant, to prepare a slurry, which is then granulated by a method such as spray drying. The granulated powder is then pressure-molded to form multiple ceramic green bodies.

[0083] The AlN ceramic raw material powder is preferably highly pure, preferably 96% or more, more preferably 99% or more, and even more preferably 99.9% or more. The average particle size of the AlN ceramic raw material powder is preferably 0.1 μm or more and 1.0 μm or less.

[0084] The mixing and molding methods are the same as those for the SiC ceramics described above. After molding, a groove may be formed on one side of the ceramic compact to match the shape of the electrode. The shape of the compact may be adjusted by machining. Machining may be performed after degreasing.

[0085] In the ceramic degreased body preparation process, the ceramic compact is degreased at a predetermined temperature or higher for a predetermined time or longer to prepare a ceramic degreased body. The conditions for the ceramic degreased body preparation process are the same as those for the SiC ceramics described above.

[0086] The electrodes are prepared in shapes that correspond to the design and application of the substrate holder and the electrode-embedding member. The electrodes can be in various shapes, such as mesh or foil, and can be made of various materials, such as molybdenum or tungsten. The electrodes and multiple ceramic degreased bodies are combined to form a flat laminate with the electrodes embedded.

[0087] In the firing process, the formed laminate is sintered under uniaxial pressure or atmospheric pressure to form a ceramic sintered body. When sintering under uniaxial pressure, the pressure is preferably 1 MPa or more. The firing temperature is preferably 1700°C or more and 2000°C or less. The firing time is preferably 1 hour or more and 12 hours or less, and more preferably 1 hour or more and 5 hours or less. The firing atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere. As a result, the degreased ceramic body is sintered to form an AlN ceramic sintered body.

[0088] In the ceramic sintered body processing step, the AlN ceramic sintered body is subjected to necessary processing, such as outer shape processing and terminal hole drilling, to form an electrode-embedding member. In the joining or fastening step between the semiconductor substrate processing base and the electrode-embedding member, if a fastening member is used, through-holes or holes for inserting the fastening member are drilled in the AlN ceramic sintered body. If necessary, grooves for disposing a sealing member may be formed in the AlN ceramic sintered body. Note that if grooves for disposing a sealing member are formed in the ceramic base of the semiconductor substrate processing base, it is not necessary to form grooves in the AlN ceramic sintered body.

[0089] (Joining or fastening process) In the bonding or fastening step, an appropriate bonding method is selected depending on the materials and CTE differences between the ceramic substrate and the electrode-embedded member of the semiconductor substrate processing base. The bonding method may be bonding with a brazing material containing a metal such as In or Al, bonding with an inorganic or organic adhesive, or bonding with a fastening member. The details of the step of bonding or fastening the semiconductor substrate processing base and the electrode-embedded member are generally similar to the step of bonding or fastening the ceramic substrate and the metal substrate described above, and therefore will not be described here.

[0090] In this manner, the substrate holding member according to the embodiment of the present invention can be manufactured.

[0091] [Examples and Comparative Examples] (Samples 1 to 7) Samples 1 to 7 were produced by the above-mentioned manufacturing method. The electrode-embedded members, ceramic substrates, metal substrates, and joining means between the substrates that constitute Samples 1 to 7 were combined as follows.

[0092] An AlN electrostatic chuck was prepared as the electrode embedding material for samples 1 to 5. The CTE and thermal conductivity of the AlN electrostatic chuck were 4.2 ppm / K and 170 W / mK, respectively. An Al2O3 electrostatic chuck was prepared as the electrode embedding material for samples 6 and 7. The CTE and thermal conductivity of the Al2O3 electrostatic chuck were 7.8 ppm / K and 30 W / mK, respectively. The dimensions of each electrostatic chuck were a diameter of 300 mm and a thickness of 6 mm. The surface roughness of the top and bottom surfaces of each electrostatic chuck was Ra 1.6 μm.

[0093] Next, several types of ceramic substrates containing SiC were prepared as the ceramic substrates for samples 1 to 7. Specifically, the ceramic substrates for samples 1 to 4 and 6 were SiC-1, the ceramic substrate for sample 5 was SiC-2, and the ceramic substrate for sample 7 was SiC-3. SiC-1 was a sintered SiC ceramic with 0.5 wt% B (boron) and 2 wt% C (carbon). SiC-2 was a sintered SiC ceramic with 47 wt% TiB2 (titanium diboride). SiC-3 was a sintered SiC ceramic with 39 wt% Ti and 16 wt% Si.

[0094] The CTE and thermal conductivity of SiC-1 were 3.9 ppm / K and 170 W / mK, those of SiC-2 were 4.2 ppm / K and 91 W / mK, and those of SiC-3 were 7.8 ppm / K and 75 W / mK.

[0095] The dimensions of each ceramic substrate were a diameter of 320 mm and a thickness of 15 mm. The surface roughness of the top and bottom surfaces of each ceramic substrate was Ra 1.6 μm. Furthermore, an opening was formed on one main surface of each ceramic substrate to serve as a spiral medium flow path, with a width of 5 to 10 mm and a depth of 10 mm, and consisting of a continuous arc.

[0096] Next, metal substrates made of W (tungsten, CTE 4.5 ppm / K), Ti alloy (CTE 8.8 ppm / K), or Al alloy (CTE 23.6 ppm / K) were prepared for samples 1 to 7. Specifically, the metal substrate for sample 1 was made of W, samples 2, 3, and 5 were made of Ti alloy, and samples 4, 6, and 7 were made of Al alloy. The dimensions of each metal substrate were a diameter of 320 mm and a thickness of 5 mm. The surface roughness of the top and bottom surfaces of each metal substrate was Ra 1.6 μm.

[0097] Next, we will explain the means for joining the ceramic substrate and the metal substrate. In Sample 1, the ceramic substrate and W (tungsten) used in the metal substrate were joined by direct bonding. In Sample 2, the ceramic substrate and the metal substrate were fastened with a fastening member. In Samples 3 to 7, the ceramic substrate and the metal substrate were joined by Al bonding. As a result, the metal substrate closed the opening provided on one main surface of the ceramic substrate, forming a media flow path.

[0098] Next, we will explain the method for joining the electrode-embedded member and the ceramic substrate. For samples 1, 2, 4, 6, and 7, the electrode-embedded member and the ceramic substrate were joined using an organic adhesive whose main component was silicone resin. For samples 3 and 5, the electrode-embedded member and the ceramic substrate were joined using aluminum bonding. Aluminum bonding is a method of joining materials by sandwiching aluminum foil as a bonding layer.

[0099] (Comparative Example 1) In Comparative Example 1, all configurations except for the metal substrate (lower substrate) were the same as those of Sample 1. In Comparative Example 1, instead of using metal as the material for the lower substrate, it was made of SiC-1. In addition, the ceramic substrate (upper substrate) and the lower substrate were directly bonded using sintered bodies. The diameter, thickness, and surface roughness of the upper and lower surfaces of the lower substrate used instead of the metal substrate were the same as when a metal substrate was used.

[0100] (Comparative Example 2) In Comparative Example 2, the semiconductor substrate processing base was made entirely of an Al alloy, and the overall size of the semiconductor substrate processing base was the same as in the cases where a ceramic base and a metal base were used.

[0101] [Load test on board holding member] The substrate holding members of the example and comparative example were connected to a water supply device capable of adjusting the pressure of the medium.

[0102] [Water flow test] After the load test on the substrate holding member, a constant pressure (4 kgf / cm 2 ) was passed through the tube, and the presence or absence of water leakage was judged visually. If there was no water leakage, it was marked as "○", and if there was water leakage, it was marked as "×".

[0103] [Measurement of flatness change] The change in flatness of the upper surface of the electrode-embedded member on the fabricated substrate holding member was measured using a three-dimensional measuring device. A change in flatness of less than 5 μm was marked "◎", a change in flatness of 5 to 10 μm was marked "○", and a change in flatness of more than 10 μm was marked "×".

[0104] [result] FIG. 5 is a table showing the configuration of the substrate holding members of the example and comparative examples, the presence or absence of water leakage, and the evaluation of flatness change. The evaluation results for water flow showed no water leakage in Samples 1 to 7 and Comparative Examples 1 and 2. The evaluation results for flatness change showed that the change in flatness was suppressed to 10 μm or less in all Samples 1 to 7. Furthermore, the change in flatness for Samples 3, 5, and 7 was less than 5 μm, resulting in evaluation results for flatness change equivalent to those of Comparative Example 1. On the other hand, in Comparative Example 2, the substrate bonded to the electrode-embedded member was an Al alloy, and therefore the CTE difference with the electrode-embedded member was greater than the CTE difference between the electrode-embedded member and the ceramic substrate in Samples 1 to 7. This is presumably why unacceptable warpage occurred in the electrode-embedded member.

[0105] From the above results, it was confirmed that the substrate holding member of the present invention is a substrate holding member that can be expected to have the effect of suppressing warping and peeling of electrode-embedded members, which is required in environments with very high heat such as semiconductor processes.

[0106] In other words, the semiconductor substrate processing base or substrate holding member of the present invention can reduce the difference in CTE between the ceramic base and the electrode-embedded member bonded to the upper surface of the ceramic base, thereby suppressing warping and peeling of the electrode-embedded member and making it easier to handle than a base formed entirely of a ceramic sintered body.

[0107] The present invention is not limited to the above-described embodiments, and various modifications and equivalents are included within the spirit and scope of the present invention. Furthermore, the structure, shape, number, position, size, etc. of the components shown in each drawing are for the convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0108] 100 Semiconductor substrate processing base 110 Ceramic substrate 112 One main surface 116 Other main surface 118 Media flow path 119 Opening 120 Metal base material 124 Top surface 126 holes 128 Through Hole 130 First bonding layer 140 Fastening members 150 Sealing member 200 Substrate holding member 210 Electrode embedding member 212 Substrate mounting surface 214 Bottom surface 218 Electrode 220 Second bonding layer

Claims

1. A semiconductor substrate processing base, a ceramic substrate formed of a ceramic sintered body and having a portion of a medium flow path having an opening; a metal base member that closes the opening of the medium flow path.

2. 2. The semiconductor substrate processing base according to claim 1, wherein the ceramic base and the metal base are bonded together with a bonding material.

3. 2. The semiconductor substrate processing base according to claim 1, wherein the ceramic base and the metal base are fastened together by a fastening member.

4. 2. The semiconductor substrate processing base according to claim 1, wherein the ceramic base and the metal base are joined by direct bonding.

5. 5. The semiconductor substrate processing base according to claim 1, wherein the ceramic sintered body contains SiC.

6. a semiconductor substrate processing base according to any one of claims 1 to 4; a second electrode-embedded member formed of a sintered ceramic body and bonded to one main surface of the semiconductor substrate processing base on the ceramic member side.

7. 7. The substrate holding member according to claim 6, wherein the difference in CTE between the ceramic sintered body and the second ceramic sintered body is 4.0 ppm / K or less.

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