Semiconductor substrate processing base, substrate holding member, and method for manufacturing the same

Abstract

To provide a semiconductor substrate processing base in which even when an unintended external force is applied to the semiconductor substrate processing base, internal stress is relieved and the effect of the external force is suppressed, a substrate holding member, and a method for manufacturing the same.SOLUTION: A semiconductor substrate processing base 100 comprises a ceramic base 110 formed by a ceramic sintered body having a media flow path 118, and an Al film 120 formed on the surface of media flow path 118. This allows unintended external forces applied to the media semiconductor substrate processing base to be mitigated by the plastic deformation of the Al film, thereby suppressing the effects of stress.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor substrate processing base, a substrate holding member using the same, and a method for manufacturing the same. [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 an electrostatic chuck that includes a ceramic base having an upper surface that serves as an attracting surface for attracting an object to be attracted, an attracting electrode provided on the ceramic base, and a flow path provided inside the ceramic base, in which a cerium compound is present on the inner surface of the flow path, and the cerium compound is formed in the form of a film.

[0005] Patent Document 2 discloses an electrostatic chuck including a chuck member having a chuck portion on a first surface side, a hollow member located opposite the chuck portion and having a space inside, a base member located opposite the chuck member with the hollow member in between, a first bonding member located between the chuck member and the hollow member, and a second bonding member located between the hollow member and the base member, wherein the hollow member is made of an insulating material and further has a metal layer covering the periphery of the space. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6034402 [Patent Document 2] Japanese Patent Publication No. 2022-11991 Summary of the Invention [Problem to be solved by the invention]

[0007] Because ceramics are brittle materials, problems can occur when an impact is applied to the base due to an unintended external force. However, neither Patent Document 1 nor Patent Document 2 takes into consideration how to mitigate the application of an unintended external force to a ceramic base and reduce the risk of problems occurring.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a semiconductor substrate processing base, a substrate holding member, and a method for manufacturing the same, which can alleviate internal stress and suppress the effects of external forces even if an unintended external force is applied to the semiconductor substrate processing base. [Means for solving the problem]

[0009] (1) In order to achieve the above object, the present invention provides the following means: A semiconductor substrate processing base according to an embodiment of the present invention is a semiconductor substrate processing base characterized by comprising a ceramic base formed of a ceramic sintered body having a media flow path, and an Al film formed on the surface of the media flow path.

[0010] By forming an Al film on the surface of the media flow path, even if an unintended external force is applied to the semiconductor substrate processing base, the internal stress is alleviated by the plastic deformation of the Al film, thereby suppressing the effects of the stress. Furthermore, by coating the media flow path surface with an Al film, compressive stress is induced on the inner surface of the media flow path in the ceramic base, which is expected to suppress stress caused by unintended external forces. As a result, the semiconductor substrate processing base can provide stable cooling performance.

[0011] (2) In the semiconductor substrate processing base of the application example (1) above, the thickness of the Al film is 100 μm or more, thereby enabling the stress relaxation effect to be fully exerted.

[0012] (3) In the semiconductor substrate processing base according to the application example of (1) or (2), the maximum diameter of the medium flow path in a cross section perpendicular to the medium flow path is 5 mm or more, which allows a large volume of medium to flow through the medium flow path and a large amount of heat to pass through the semiconductor substrate processing base.

[0013] (4) In addition, in the semiconductor substrate processing base according to any one of the application examples (1) to (3) above, the ceramic base is characterized in that it comprises a bonding layer and a first ceramic member and a second ceramic member bonded via the bonding layer, the medium flow path is formed by the first ceramic member and the second ceramic member, and the bonding layer is made of a second Al film. This makes it possible to specifically configure a semiconductor substrate processing base having an internal medium flow path with an Al film formed on its surface. Furthermore, if the second Al film is formed simultaneously with the Al film, the manufacturing process for the semiconductor substrate processing base is simplified, resulting in cost reduction.

[0014] (5) The semiconductor substrate processing base according to any one of the application examples (1) to (4) above may further include a third Al film formed on at least a portion of the outer surface of the ceramic base. This reduces external forces on the outer surface, allowing the semiconductor substrate processing base to stably perform its cooling function. Furthermore, when applying a high-frequency current to the semiconductor substrate processing base or a high-frequency electrode provided on the semiconductor substrate processing base, the third Al film can also be used as a terminal or high-frequency electrode, which can reduce the impedance of the semiconductor substrate processing base in the high-frequency band, thereby further improving the uniformity of the process in which the high-frequency current is applied.

[0015] (6) In addition, in the semiconductor substrate processing base of any of the application examples (1) to (5) above, the ceramic base is characterized in that it is formed of a ceramic containing SiC. This makes it suitable for use as a semiconductor substrate processing base for cooling. In addition, since SiC itself is conductive, it can also serve as an electrode for high-frequency current.

[0016] (7) 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 (6) above; a second bonding layer formed on one main surface of the semiconductor substrate processing base; and an electrostatic chuck or heater plate bonded to the semiconductor substrate processing base via the second bonding layer and formed of a second ceramic sintered body.

[0017] In this way, by forming an Al film on the surface of the media flow path, even if an unintended external force is applied to the semiconductor substrate processing base, the internal stress is alleviated by the plastic deformation of the Al film, thereby suppressing the effects of the stress. Furthermore, by forming the semiconductor substrate processing base and the electrostatic chuck or heater plate from ceramics, their CTEs are close to each other, which suppresses deformation or warping of the electrostatic chuck or heater plate and poor adhesion between the electrostatic chuck or heater plate and the semiconductor substrate processing base, resulting in a stable structure.

[0018] (8) Furthermore, a method for manufacturing a semiconductor substrate processing base according to an application example of the present invention includes the steps of: preparing a first ceramic member and a second ceramic member made of a ceramic containing SiC, with a groove formed in at least one of them to serve as a media flow path; forming an Al film by cold spraying on the portion of the first ceramic member or the second ceramic member that will serve as the media flow path; forming a second Al film at the bonding interface between the first ceramic member or the second ceramic member; and bonding the first ceramic member and the second ceramic member using the second Al film as a bonding layer.

[0019] This allows the production of a semiconductor substrate processing base that can suppress the effects of stress even if an unintended external force is applied to the semiconductor substrate processing base, as the internal stress is alleviated by the plastic deformation of the Al film. [Effects of the Invention]

[0020] According to the semiconductor substrate processing base or substrate holding member of the present invention, even if an unintended external force is applied to the semiconductor substrate processing base, the internal stress is alleviated by the plastic deformation of the Al film, thereby suppressing the influence of the stress.Furthermore, the manufacturing method of the present invention can manufacture such a semiconductor substrate processing base. [Brief explanation of the drawings]

[0021] [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] 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 5]1 is a schematic cross-sectional view showing an example of a substrate holding member according to an embodiment of the present invention. [Figure 6] FIG. 10 is a schematic cross-sectional view showing a modified example of a substrate holding member according to an embodiment of the present invention. [Figure 7] 3(a) to 3(c) are schematic cross-sectional views each showing a step in a method for manufacturing a semiconductor substrate processing base according to an embodiment of the present invention. [Figure 8] 1A to 1C are schematic cross-sectional views showing a step in a method for manufacturing a semiconductor substrate processing base according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] 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.

[0023] [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 100 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 an Al film 120.

[0024] The ceramic base 110 is formed of a sintered ceramic body having a media flow path 118 therein. The ceramic base 110 can be formed of, for example, ceramics containing SiC, ceramics containing AlN, or ceramics containing Al2O3. The ceramic base 110 is formed in a generally flat plate shape with a diameter of 200 mm or more and a thickness of 10 to 50 mm. The ceramic base 110 may have various shapes, such as a generally circular plate, a polygonal plate, or an elliptical plate. The dotted lines in FIG. 1 indicate the bonding surfaces.

[0025] The ceramic base 110 is preferably made of ceramics with a thermal conductivity of 60 W / mK or more. This allows the ceramic base 110 itself to have high thermal conductivity, making it suitable for use as a cooling semiconductor substrate processing base 100. Examples of ceramics with a thermal conductivity of 60 W / mK or more include ceramics containing SiC and ceramics containing AlN.

[0026] The ceramic base 110 is preferably formed of a ceramic sintered body whose main component is SiC or AlN. "SiC-based" 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 60 W / mK or more. "AlN-based" refers to a ceramic sintered body containing 50 wt% or more of AlN, or a ceramic sintered body containing AlN and having a thermal conductivity of 60 W / mK or more. SiC, in particular, has high strength and thermal conductivity, making it suitable for use as the semiconductor substrate processing base 100 for cooling.

[0027] The Al film 120 is formed on the surface of the medium flow path 118. By forming the Al film 120 on the surface of the medium flow path 118 in this way, even if an unintended external force is applied to the semiconductor substrate processing base 100, the internal stress is alleviated by the plastic deformation of the Al film 120, thereby suppressing the effects of the stress. Furthermore, by coating the surface of the medium flow path 118 with the Al film 120, compressive stress is induced on the inner surface of the base's medium flow path 118, which is expected to have the effect of suppressing stress caused by unintended external forces. As a result, the semiconductor substrate processing base 100 can stably perform its cooling function.

[0028] The thickness of the Al film 120 is preferably 100 μm or more. This allows the stress relaxation effect to be fully exerted. The thickness of the Al film 120 is the minimum distance from the interface between the ceramic base 110 and the Al film 120 to the surface of the Al film 120 in a direction perpendicular to the interface in a cross section perpendicular to the media flow path 118. The cross section perpendicular to the media flow path 118 is a cross section obtained by cutting in a direction perpendicular to the flow direction of the media flow path 118. The thickness of the Al film 120 is preferably 2000 μm or less, and more preferably 1000 μm or less. If the Al film 120 is thinner than 100 μm, the stress relaxation effect is reduced. If the Al film 120 is thicker than 2000 μm, there is an increased risk of the Al film 120 peeling off at the interface with the ceramic base 110 or by scraping off the surface of the ceramic base 110.

[0029] The medium flow path 118 may be formed in a tubular shape. In this case, the cross-sectional shape of the medium flow path 118 is not limited to a rectangle, but may be any manufacturable shape, such as a circle, an ellipse, a semicircle, or a stepped shape. The medium flow path 118 preferably uses a low-temperature chiller for circulation. Therefore, the medium flow path 118 preferably has an inlet for introducing the chiller and an outlet for discharging the chiller. In this case, the medium flow path 118 is connected to a chiller unit provided outside a reduced-pressure vessel or the like in which the semiconductor substrate processing base 100 is installed.

[0030] When the medium channel 118 is formed in a tubular shape, the maximum diameter of the medium channel 118 is preferably 5 mm or more. This allows a large volume of medium to flow. The maximum diameter of the medium channel 118 is the maximum value between two points on the surface of the medium channel 118 (the interface between the ceramic base 110 and the Al film 120) in a cross section perpendicular to the medium channel 118. The maximum diameter of the medium channel 118 is preferably 60 mm or less.

[0031] For example, if the cross section of the medium flow path 118 is rectangular, it is preferable that the width or depth is 2 mm or more. If it is smaller than this, the pressure loss will be large, making it difficult to increase the flow rate and volume of the medium, and it may be difficult to absorb a large amount of heat. It is preferable that the width or depth is 10 mm or more.

[0032] The shape of the medium flow path 118, when viewed from above through the ceramic base 110, may include a substantially circular or spiral shape centered on the center of the ceramic base 110. A substantially circular shape includes a shape in which some of the arcs of the circular ring are not connected, as well as a normal circular ring. A substantially spiral shape includes a shape in which the circumferential arc shapes are connected with their curvature changing in the radial direction with the center of the ceramic base 110 as the base.

[0033] The medium flow channels 118 may be arranged concentrically around the center of the ceramic base 110 when viewed from above the ceramic base 110. 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 base 110, or each may be formed with an inlet and an outlet.

[0034] The width of the gap between adjacent media flow channels 118 (the width of the ceramic base 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 base 110 to be maintained without sacrificing heat exchange by the medium, even when the media flow channel 118 is formed inside the ceramic base 110 made of ceramic.

[0035] 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.

[0036] 2 and 3 are schematic cross-sectional views illustrating modified examples of the semiconductor substrate processing base 100 according to an embodiment of the present invention. As shown in FIG. 2 or 3, the ceramic base 110 preferably comprises a bonding layer 130 and a first ceramic member 141 and a second ceramic member 142 bonded together via the bonding layer 130. In this case, the medium flow path 118 is preferably formed from the first ceramic member 141 and the second ceramic member 142, and the bonding layer 130 is preferably formed from a second Al film 122. This configuration specifically configures the semiconductor substrate processing base 100 having the medium flow path 118 with the Al film 120 formed on its surface. Furthermore, forming the second Al film 122 and the Al film 120 simultaneously simplifies the manufacturing process of the semiconductor substrate processing base 100, thereby reducing costs.

[0037] The thickness of the second Al film 122 is preferably 100 μm or more and 2000 μm or less, and more preferably 100 μm or more and 1000 μm or less. The thickness of the second Al film 122 may be different between the portion where the first ceramic member 141 and the second ceramic member 142 are joined and the portion that becomes the surface of the media flow path 118.

[0038] An insulating layer 150 may be formed on (the surface side of) the second Al film 122 where the second Al film 122 is exposed on the surface of the semiconductor substrate processing base 100. This allows electrical insulation from the process environment and the surroundings to be maintained. The insulating layer 150 can be formed, for example, by a thermally sprayed Al2O3 film or a seal made of an organic adhesive.

[0039] 4 is a schematic cross-sectional view showing a modified example of the semiconductor substrate processing base 100 according to the embodiment of the present invention. As shown in FIG. 4, the semiconductor substrate processing base 100 preferably further includes a third Al film 123 formed on at least a portion of the outer surface of the ceramic base 110 (one main surface 112, the side surface 114, and the other main surface 116 opposite the one main surface 112).

[0040] This reduces the external force on the outer surface, allowing the semiconductor substrate processing base 100 to stably perform its cooling function. Furthermore, when applying a high-frequency current to the semiconductor substrate processing base 100 itself or to a high-frequency electrode provided on the semiconductor substrate processing base 100, the third Al film 123 can also be used as a terminal or a high-frequency electrode. This reduces the impedance of the semiconductor substrate processing base 100 in the high-frequency band, thereby further improving the uniformity in the process of applying a high-frequency current. Furthermore, since power can be supplied from the outer surface of the ceramic base 110, greater freedom in the design of the device structure including the substrate holding member 200 is provided.

[0041] The thickness of the third Al film 123 is preferably 100 μm or more and 2000 μm or less, and more preferably 100 μm or more and 1000 μm or less. The thickness of the third Al film 123 may vary depending on the purpose and function. When the ceramic base 110 is formed of a conductive ceramic, the third Al film 123 that functions as a high-frequency electrode may or may not be provided.

[0042] When both the second Al film 122 and the third Al film 123 are formed, it is preferable that the second Al film 122 and the third Al film 123 are insulated from each other by an insulating layer 150 or the like. Furthermore, the insulating layer 150 may be formed on (on the surface side of) the third Al film 123 on the side surface 114 or the like where the third Al film 123 is exposed. This makes it possible to maintain electrical insulation from the process environment and the surroundings. The insulating layer 150 can be formed, for example, by a thermally sprayed film of Al2O3 or a seal made of an organic adhesive.

[0043] (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. 5. Fig. 5 is a schematic cross-sectional view showing an example of a substrate holding member 200 according to an embodiment of the present invention. The substrate holding member 200 according to an embodiment of the present invention includes a semiconductor substrate processing base 100, a second bonding layer 210, and an electrostatic chuck or heater plate 220. The semiconductor substrate processing base 100 is the same as described above.

[0044] The second bonding layer 210 is formed on one main surface 112 of the semiconductor substrate processing base 100 (ceramic base 110). The second bonding layer 210 is preferably formed from a brazing material containing a metal such as In, Al, or Au, an inorganic adhesive, an organic adhesive containing a resin material as a main component, or the third Al film 123 described below. Various materials can be used as the resin-based adhesive, such as silicone resin, fluororesin, acrylic resin, or epoxy resin. Among these, it is preferable to use silicone resin or fluororesin, which have high heat resistance and flexibility.

[0045] When the second bonding layer 210 is formed from 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 210 is preferably 0.4 W / mK or higher. Furthermore, the elongation of the second bonding layer 210 is preferably 100% or higher. The thickness of the second bonding layer 210 is preferably 500 μm or less, and more preferably 100 μm or less. This allows a large amount of heat to be transferred. If the thickness is greater than 500 μm, the thermal resistance of the second bonding layer 210 may not be negligible even if a highly thermally conductive metal or adhesive is used. The lower limit of the thickness of the second bonding layer 210 can be, for example, 10 μm or more. This is because thicknesses thinner than this make it difficult to control the thickness.

[0046] The electrostatic chuck or heater plate 220 is bonded to one main surface 112 of the ceramic base 110 via a second bonding layer 210. The electrostatic chuck or heater plate 220 has a substrate mounting surface 222.

[0047] An electrode 224 (electrode for electrostatic attraction or electrode for heater) is embedded in the electrostatic chuck or heater plate 220. The electrode 224 may have various shapes, such as a mesh shape or a foil shape, and may be made of various materials, such as molybdenum or tungsten.

[0048] The electrostatic chuck or heater plate 220 is preferably formed of a second ceramic sintered body. This reduces the difference in CTE between the electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100, reducing the risk of warping of the electrostatic chuck or heater plate 220 and poor adhesion to the semiconductor substrate processing base 100. This also allows the electrostatic chuck or heater plate 220 to function as an electrically insulating, dense, and highly thermally conductive insulating member. Furthermore, the electrode 224 can be easily embedded. The second ceramic sintered body forming the electrostatic chuck or heater plate 220 may have the same or different main component as the ceramic sintered body forming the ceramic base 110. The thickness of the electrostatic chuck or heater plate 220 is preferably 1 mm or more and 20 mm or less.

[0049] The electrostatic chuck or heater plate 220 is preferably made of ceramics containing AlN, Al2O3, or Y2O3 as its main component, and more preferably AlN, which has excellent thermal conductivity. In the electrostatic chuck or heater plate 220, "mainly composed" refers to ceramics containing 50 wt% or more of that compound.

[0050] Fig. 6 is a schematic cross-sectional view showing a modified example of a substrate holding member 200 according to an embodiment of the present invention. The substrate holding member 200 in Fig. 6 includes a third Al film 123. The substrate holding member 200 in Fig. 6 uses the third Al film 123 formed on one main surface 112 of the ceramic base 110 as a second bonding layer 210. Even when the third Al film 123 is formed on one main surface 112 of the ceramic base 110, the second bonding layer 210 may be provided on the third Al film 123 for bonding.

[0051] Power may be supplied to the electrode 224 through a third Al film 123 formed on the side surface 114 of the ceramic base 110. Alternatively, a third Al film 123 formed on the other main surface 116 of the ceramic base 110 may also be used. When the third Al film 123 formed on one main surface 112 of the ceramic base 110 is used as a high-frequency electrode, the third Al film 123 for supplying power to the high-frequency electrode and the third Al film 123 for supplying power to the electrode 224 are formed to be separate systems. Power may be supplied to the electrode 224 through a terminal (not shown).

[0052] [Method of manufacturing a semiconductor substrate processing base] Next, an example of a method for manufacturing a semiconductor substrate processing base according to an embodiment of the present invention will be described. Figures 7(a) to 7(c) and 8 are schematic cross-sectional views showing a step in the method for manufacturing a semiconductor substrate processing base according to an embodiment of the present invention. Figures 7(a) to 7(c) and 8 show only the characteristic steps of the manufacturing method of the present invention.

[0053] FIG. 7(a) illustrates the process of preparing a first ceramic member 141 and a second ceramic member 142 made of SiC-containing ceramics, at least one of which has a groove formed therein to form the media flow path 118. FIG. 7(b) illustrates the process of forming an Al film 120 by cold spraying on the portion of the first ceramic member 141 or the second ceramic member 142 that will form the media flow path 118, and the process of forming a second Al film 122 at the bonding interface between the first ceramic member 141 or the second ceramic member 142. FIG. 7(c) illustrates the process of bonding the first ceramic member 141 and the second ceramic member 142 using the second Al film 122 as a bonding layer 130. FIG. 8 illustrates the manufactured semiconductor substrate processing base 100.

[0054] The first ceramic member 141 and the second ceramic member 142 (hereinafter referred to as ceramic members) prepared by the above manufacturing method may be manufactured by, for example, the following manufacturing methods. As specific examples, the following will be described below: a manufacturing method for a ceramic member when the ceramic member is manufactured by a molded body hot pressing method; a manufacturing method for a semiconductor substrate processing base 100 including a cold spray method and a bonding method; and a manufacturing method for a substrate holding member 200 when the electrostatic chuck or heater plate 220 is manufactured by a molded body hot pressing method.

[0055] (Method for manufacturing ceramic member (ceramic member preparation process)) The ceramic member according to the embodiment of the present invention is produced, for example, by a molded body hot pressing method described below. Note that the method for producing the ceramic member is not limited to this method, and other methods such as a powder hot pressing method or a conventional green sheet lamination method may also be used. 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 uniaxial hot press fired.

[0056] The method for manufacturing a ceramic member by 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, and a ceramic sintered body processing step.

[0057] In the ceramic green body forming process, multiple ceramic green bodies are formed from ceramic raw material powder mainly composed of, for example, silicon carbide (SiC). Sintering aids and additives may be added as needed. For example, sintering aids such as B4C and C, binders, plasticizers, dispersants, and other additives 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 additives may be nitrides, carbides, or borides of metals selected from Groups 4 to 6 of the periodic table. These components may be added to adjust the difference in linear expansion coefficient, thermal conductivity, and other physical properties between the ceramic base 110 and the electrostatic chuck or heater plate 220 mounted on the ceramic base 110. The granulated powder is then pressure-molded to form multiple ceramic green bodies.

[0058] 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.

[0059] 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.

[0060] After molding, the ceramic molded body may be machined to adjust the shape of the molded body. Grooves, inlets, and outlets that will become the media flow paths may be formed at this time. Alternatively, the grooves, inlets, and outlets that will become the media flow paths may be roughly machined. Machining may be performed after degreasing.

[0061] In the ceramic degreased body production process, multiple 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.

[0062] In the firing process, the formed ceramic degreased body is subjected to uniaxial pressure firing or atmospheric pressure firing to form multiple ceramic sintered bodies. When uniaxial pressure firing is used, the pressure is preferably 4 MPa or more. The firing temperature is preferably 1900°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. This sinters the multiple ceramic degreased bodies into multiple SiC ceramic sintered bodies. A calcination process may be performed between the ceramic degreased body preparation process and the firing process.

[0063] In the ceramic sintered body processing step, one or more SiC ceramic sintered bodies are processed as necessary to form at least first and second ceramic members 141 and 142. Three or more ceramic members may be formed. Examples of the ceramic members include a ceramic member that serves as a cover for the media flow channel 118 and a ceramic member that forms part of the media flow channel 118. For example, grooves, inlets, and outlets that will become the media flow channel 118 after bonding are formed in one or more SiC ceramic sintered bodies. The media flow channel 118 may be formed by covering a groove formed in one ceramic member with another ceramic member (a SiC ceramic sintered body). Alternatively, the media flow channel 118 may be formed by combining grooves formed in two ceramic members. This method allows for the formation of media flow channels with various shapes. If the grooves, inlets, and outlets that will become the media flow channel 118 have been roughly processed in the degreased ceramic body or the calcined ceramic body, the final processing may be performed in the ceramic sintered body processing step.

[0064] (Al film forming process) In the Al film deposition process, the Al film 120 is preferably deposited by cold spraying on the portion of the first ceramic member 141 or the second ceramic member 142 that will become the medium flow path 118. The thickness of the Al film 120 is preferably 100 μm or more and 2000 μm or less. The surface on which the Al film 120 is deposited may be a sintered surface to enhance the anchoring effect. Furthermore, the surface on which the Al film 120 is deposited may be processed to have a surface roughness Ra of 0.1 μm or more and 4.0 μm or less to improve dimensional accuracy. The surface on which the Al film 120 is deposited is preferably preheated to 100 to 400°C. Granulated powder is preferably used as the raw material powder for cold spraying. The granulated powder preferably has a granulation dimension D50 of 10 to 100 μm. The discharge pressure is preferably 1 to 10 MPa. The discharge flow rate is preferably 500 to 4000 SLM. The Al film 120 does not need to be formed on the inlet or outlet.

[0065] The cold spray method allows film formation at room temperature or a relatively low temperature, and can prevent the Al film 120 from peeling off from the ceramic member. The Al film 120 is preferably made of Al with a purity of 99.7% or higher. When the Al film 120 is formed by the cold spray method, the purity can be set within a wide range of, for example, 99.7 to 99.99% and the thickness can be set within a range of 10 to 2000 μm. The Al film 120 can also be formed by conventional methods such as thermal spraying and PVD.

[0066] (Second Al film formation process) In the second Al film deposition process, a second Al film 122 is formed at the bonding interface between the first ceramic member 141 or the second ceramic member 142. Various methods can be used to form the second Al film 122, including placing an Al foil at the bonding interface between the first ceramic member 141 or the second ceramic member 142, cold spraying, conventional thermal spraying, and PVD. Among these, cold spraying is preferred. Forming the second Al film 122 simultaneously with or consecutively to the Al film 120 simplifies the manufacturing process of the semiconductor substrate processing base 100 and reduces costs. The surface on which the second Al film 122 is deposited may be a annealed surface to enhance the anchoring effect. The surface on which the second Al film 122 is deposited may also be processed to have a surface roughness Ra of 0.1 μm to 4.0 μm to improve dimensional accuracy.

[0067] (Joining process) In the bonding process, the first ceramic member 141 and the second ceramic member 142 are bonded together using the second Al film 122 as the bonding layer 130. The first ceramic member 141 and the second ceramic member 142 are placed in a predetermined position and heated while applying pressure perpendicular to the upper surface. The pressure is preferably 0.001 to 10 MPa. The heating temperature is preferably 500°C to 700°C. The heating time is preferably 0.1 to 5 hours. The heating atmosphere is appropriately selected from, for example, air, an inert gas atmosphere such as nitrogen, or a vacuum atmosphere. This bonding process allows the first ceramic member 141 and the second ceramic member 142 to be bonded together to produce a semiconductor substrate processing base 100 having the Al film 120 formed in the internal medium flow path 118.

[0068] The bonding process may be performed using a brazing material containing a metal such as In, Al, Au, or Ag, or a brazing material containing these metals plus an active metal such as Ti, Hf, or Zr. In this case, a metal paste printing process may be performed instead of the second Al film formation process. Metal foil may be used as the brazing material. Furthermore, the bonding surfaces may be metallized with Ti, Cr, Cu, or the like, as needed.

[0069] After the bonding step, the outer shape of the semiconductor substrate processing base 100 is processed as needed. If necessary, for example, when terminals are used for electrical connection of the electrostatic chuck or the heater plate 220, through holes or the like are drilled for connecting the terminals. Note that the drilling of through holes or the like may be performed before the bonding step.

[0070] After the bonding step, a third Al film 123 may be formed on the outer surface (one of the main surfaces 112, the side surface 114, or the other main surface 116) of the ceramic base 110. The surface on which the third Al film 123 is formed may be a sintered surface to enhance the anchoring effect. Furthermore, the surface on which the third Al film 123 is formed may be processed to have a surface roughness Ra of 0.1 μm or more and 4.0 μm or less to improve dimensional accuracy.

[0071] The third Al film 123 is preferably formed by cold spraying. The third Al film 123 is preferably made of Al with a purity of 99.7% or higher. When the third Al film 123 is formed by cold spraying, the purity can be set within a wide range of, for example, 99.7 to 99.99% and the thickness can be set within a wide range of 10 to 2000 μm. The material and thickness of the Al film 120, the second Al film 122, and the third Al film 123 may be the same or different.

[0072] When the third Al film 123 is used as a high-frequency electrode or as a terminal, the electrical conductivity can be adjusted by adjusting the purity of the raw material powder. The third Al film 123 has high conductivity and can function as a sufficient high-frequency conductor even when it is thin, so the film thickness may be adjusted according to the purity of the raw material powder. The third Al film 123 can also be formed by conventional methods such as thermal spraying and PVD.

[0073] After bonding, a step of forming an insulating layer 150 on the portion of the second Al film 122 exposed on the outer surface of the semiconductor substrate processing base 100 may be provided. Alternatively, after forming the third Al film 123, a step of forming the insulating layer 150 on the third Al film 123 may be provided. It is preferable that the second Al film 122 and the third Al film 123 are insulated from each other. The step of forming the insulating layer 150 may be performed after bonding the semiconductor substrate processing base 100 and the electrostatic chuck or heater plate 220. The insulating layer 150 can be formed, for example, by spraying Al2O3 or sealing with an organic adhesive.

[0074] (Method of manufacturing an electrostatic chuck or heater plate) When the electrostatic chuck or heater plate 220 of the substrate holding member 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 electrostatic chuck or heater plate 220 is not limited to this method, and may be, for example, a powder hot pressing method or a conventional green sheet lamination method.

[0075] The manufacturing method of the electrostatic chuck or heater plate 220 of the substrate holding member according to the embodiment of the present invention by the molded body hot pressing method includes a ceramic molded body forming step, a ceramic degreased body producing step, a firing step, and a ceramic sintered body processing step.

[0076] 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.

[0077] 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.

[0078] 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 (the surface to be joined with another ceramic compact) in a shape that matches the shape of the electrode 224. The shape of the compact may be adjusted by machining. Machining may be performed after degreasing.

[0079] In the ceramic degreased body preparation process, a plurality of ceramic compacts are degreased at a predetermined temperature or higher for a predetermined time or longer to prepare a plurality of ceramic degreased bodies. The conditions for the ceramic degreased body preparation process are the same as those for the SiC ceramics described above.

[0080] The electrode 224 (electrode for electrostatic attraction or electrode for heater) is prepared in a shape that corresponds to the design and application of the electrostatic chuck or heater plate 220 and the substrate holding member 200. The electrode 224 may be formed in various shapes, such as a mesh or foil. The electrode 224 may also be made of various materials, such as molybdenum or tungsten. The electrode 224 and a plurality of ceramic degreased bodies are combined to form a flat-shaped laminate in which the electrode 224 is embedded.

[0081] In the firing step, the formed laminate is subjected to uniaxial pressure firing or atmospheric pressure firing to form a ceramic sintered body. When uniaxial pressure firing is performed, 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, one or more degreased ceramic bodies are sintered to form an AlN ceramic sintered body.

[0082] In the ceramic sintered body processing step, the AlN ceramic sintered body is subjected to necessary processing such as processing the outer shape and drilling terminal holes, to form an electrostatic chuck or heater plate 220.

[0083] (Joining process) In the bonding process, an appropriate bonding method is selected depending on the materials and CTE difference between the fabricated electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100. The bonding method may be bonding using a brazing material containing a metal such as In, Al, Au, or Ag, or a brazing material containing these metals plus an active metal such as Ti, Hf, or Zr. A metal paste or metal foil may be used as the brazing material. Furthermore, the bonding surfaces may be metallized with Ti, Cr, Cu, or the like, as needed. Furthermore, the bonding method may be bonding using an inorganic adhesive or an organic adhesive. Furthermore, the bonding method may be a method using a third Al film 123 as a bonding layer.

[0084] When bonding using brazing material, it is preferable that the surface roughness Ra of the bonding surfaces of the electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100 be 1.6 μm or less. Then, the brazing material is placed between the bonding surfaces of the electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100, and the bonding is achieved by heating to the melting point or glass transition point of the brazing material while applying a force of 0.001 MPa or more in a direction perpendicular to the bonding surfaces.

[0085] When bonding is performed using an inorganic or organic adhesive, the bonding surfaces of the electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100 preferably have a surface roughness Ra of 1.6 μm or less. The bonding surfaces of the electrostatic chuck or heater plate 220 and the semiconductor substrate processing base 100 are then bonded by placing the adhesive between them and heating them to the glass transition point of the adhesive. When using an adhesive, it is preferable that a filler be added to the adhesive to increase thermal conductivity.

[0086] When the third Al film 123 is formed on one main surface 112 of the ceramic base 110 and is bonded as the second bonding layer 210, the bonding surfaces of the electrostatic chuck or heater plate 220 and the third Al film 123 preferably have a surface roughness Ra of 0.2 μm or less, more preferably 0.1 μm or less. Then, the bonding surfaces of the electrostatic chuck or heater plate 220 and the third Al film 123 are brought together and bonded by applying a force of 0.001 to 10 MPa in a direction perpendicular to the bonding surfaces and heating to 500 to 700°C.

[0087] In this manner, the substrate holding member 200 according to the embodiment of the present invention can be manufactured.

[0088] As described above, according to the semiconductor substrate processing base or substrate holding member of the present invention, even if an unintended external force is applied to the semiconductor substrate processing base, the internal stress is alleviated and the effects of the external force can be suppressed.

[0089] 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]

[0090] 100 Semiconductor substrate processing base 110 Ceramic base 112 One main surface 114 Side 116 Other main surface 118 Media flow path 120 Al film 122 Second Al film 123 Third Al film 130 Bonding layer 141 First ceramic member 142 Second ceramic component 150 insulating layer 200 Substrate holding member 210 Second bonding layer 220 Electrostatic Chuck or Heater Plate 222 Substrate mounting surface 224 Electrode

Claims

1. A semiconductor substrate processing base, a ceramic base formed of a ceramic sintered body having a medium flow path; an Al film formed on the surface of the medium flow path.

2. 2. The semiconductor substrate processing base according to claim 1, wherein the thickness of said Al film is 100 [mu]m or more.

3. 3. The semiconductor substrate processing base according to claim 1, wherein the maximum diameter of the medium flow path in a cross section perpendicular to the medium flow path is 5 mm or more.

4. the ceramic base includes a bonding layer and a first ceramic member and a second ceramic member bonded to each other via the bonding layer; the medium flow path is formed by the first ceramic member and the second ceramic member, 3. The semiconductor substrate processing base according to claim 1, wherein the bonding layer is made of a second Al film.

5. 3. The semiconductor substrate processing base according to claim 1, further comprising a third Al film formed on at least a portion of the outer surface of the ceramic base.

6. 3. The semiconductor substrate processing base according to claim 1, wherein the ceramic base is made of ceramic containing SiC.

7. a semiconductor substrate processing base according to claim 1 or 2; a second bonding layer formed on one main surface of the semiconductor substrate processing base; a substrate holding member bonded to the semiconductor substrate processing base via the second bonding layer, and an electrostatic chuck or heater plate formed of a second ceramic sintered body.

8. preparing a first ceramic member and a second ceramic member made of ceramics containing SiC, at least one of which has a groove formed therein to serve as a media flow path; forming an Al film on a portion of the first ceramic member or the second ceramic member that will become the medium flow path by a cold spray method; forming a second Al film on a bonding interface between the first ceramic member or the second ceramic member; and bonding the first ceramic member and the second ceramic member together using the second Al film as a bonding layer.

Images