Electrode-embedding member, its manufacturing method, and substrate holding member

Abstract

To provide an electrode embedded member and a substrate holding member, capable of reducing the occurrence of local hot spots, capable of suppressing the biting of particles, and capable of using a space under a substrate as a gas flow channel as necessary.SOLUTION: An electrode embedded member 100 includes a substrate 10 made of a ceramic sintered body, an electrode 20 embedded in the substrate 10, and a plurality of pin-shaped protrusions 30 formed by protruding upward from a top face 12 of the substrate 10. A profile curve 42 obtained by cutting a mounting curved surface constituted of upper ends 32 of the plurality of pin-shaped protrusions with a cross section through a Z-axis with the central axis of the substrate 10 as the Z-axis is a curve which has the maximum of the value of Z in the vicinity of the central axis and monotonically decreases towards the circumference 18 of the substrate 10 or a curve which has the minimum of the value of Z in the vicinity of the central axis and monotonically increases towards the circumference 18 of the substrate 10 when the line of intersection between the cross section and a predetermined reference surface is defined as an X-axis.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrode-embedded member, a manufacturing method thereof, and a substrate holding member. [Background technology]

[0002] Heater plates (members with embedded electrodes) with embedded electrodes (heat generating resistors) have been used as semiconductor manufacturing equipment components, and are capable of heating a substrate placed on the heater plate.

[0003] Patent Document 1 discloses a ceramic heater that includes a ceramic base provided with a heating surface that supports and heats the workpiece, a heating element embedded within the base, and an embossed portion on the heating surface that comes into contact with the workpiece, and that, for the purpose of preventing adverse effects on the workpiece due to heat spots on the heating surface, when the average temperature of the heating surface is raised to a target temperature, there are heat spots on the heating surface where the surface temperature is relatively high, and the number of embossed portions per unit area in the heat spots is smaller than the number of embossed portions per unit area in areas other than the heat spots.

[0004] Patent Document 2 discloses a hot plate and electrostatic chuck with a holding surface flatness of 1 to 50 μm. It describes how the unevenness of the wafer temperature is caused by surface undulations, and how this is kept within a specified range, that ALN is preferable for the ceramic, and that when used as a chuck, the variation in the distance between the wafer and the electrode is small, resulting in sufficient chucking force, and how the undulations are convex. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-124367 A [Patent Document 2] International Publication WO 01 / 13423 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] Electrode-embedded materials such as electrostatic chucks with built-in heaters and ceramic heaters can have abnormal heating points (hot spots). Due to the demand for process uniformity in semiconductor processes, there has been a demand for electrode-embedded materials that do not cause hot spots.

[0007] In Patent Document 1, the influence of hot spots (heat spots) is reduced by identifying the areas that will become hot spots in advance and reducing the number of embossed portions per unit area in the hot spots, but the reduction of localized hot spots is not considered. In addition, although Patent Document 2 describes application to electrostatic chucks, there is no description of protrusions, and there is no description of localized hot spots.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide an electrode embedding member and a substrate holding member that can reduce the occurrence of localized hot spots, suppress particle entrapment, and, if necessary, enable the space under the substrate to be used as a gas flow path. [Means for solving the problem]

[0009] (1) In order to achieve the above object, the electrode embedding member of the present invention is an electrode embedding member comprising a base formed of a sintered ceramic body, an electrode embedded in the base, and a plurality of pin-shaped protrusions formed so as to protrude upward from an upper surface of the base, and a cross-sectional curve obtained by cutting a mounting surface formed by the upper ends of the plurality of pin-shaped protrusions at a cross section passing through the Z axis of the base, with the central axis of the base as the Z axis, is a curve that has a maximum Z value in the vicinity of the central axis and monotonically decreases towards the outer periphery of the base, or a curve that has a minimum Z value in the vicinity of the central axis and monotonically increases towards the outer periphery of the base, when the intersection line between a predetermined reference plane and the cross section is the X axis.

[0010] In this way, by having the cross-sectional curve of the mounting surface be a curve that has a maximum Z value near the central axis and monotonically decreases toward the periphery of the base, or a curve that has a minimum Z value near the central axis and monotonically increases toward the periphery of the base, the substrate can conform better to the pin-shaped protrusions and the occurrence of localized hot spots can be reduced compared to increasing the flatness of the mounting surface to make it closer to a plane. In addition, because the substrate is supported by the pin-shaped protrusions, particle entrapment can be suppressed, and the space below the substrate can be used as a gas flow path as necessary.

[0011] (2) Books Electrode-embedding member of the invention In addition to the feature (1), The cross-sectional curve is expressed by taking the reference length in the X-axis direction as L (mm), the value of Z (mm) for a certain X (mm) as Z(X), and the value of the deviation ΔZ(X) as ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2), and taking the maximum value of ΔZ(X) as ΔZ(X). max , the minimum value of ΔZ(X) is ΔZ(X) min Then, ΔZ(X) max -ΔZ(X) min It is characterized by satisfying the requirement of ≦1 (μm).

[0012] This suppresses localized unevenness, thereby making it possible to further reduce the occurrence of localized hot spots.

[0013] (3) In the electrode-embedding member of the present invention, the flatness of the curved surface is preferably 50 μm or less.

[0014] This allows the substrate to be placed without wrinkling.

[0015] (4) Also, the present invention In another embodiment The electrode embedding member is In addition to the characteristics of (1),When a curve obtained by cutting the mounting surface at a second cross section perpendicular to the X-axis and including the Z-axis is defined as a second cross-sectional curve, and an intersection line between the predetermined reference plane and the second cross-section is defined as a Y-axis, a coefficient of determination R2 for a first approximation equation when the cross-sectional curve is approximated by a quadratic curve, and a coefficient of determination R2 for a second approximation equation when the second cross-sectional curve is approximated by a quadratic curve are both 0.99 or more.

[0016] This allows the cross-sectional curves in the X-axis and Y-axis directions to have a quadratic curve shape, and suppresses localized, irregular changes in the height direction of the cross-sectional curve, thereby further reducing the occurrence of localized hot spots.

[0017] (5) Furthermore, the electrode-embedded member of the present invention is characterized in that, when the quadratic coefficient of the first approximation equation is a(X) and the quadratic coefficient of the second approximation equation is a(Y), the relationship 2(a(X)-a(Y)) / (a(X)+a(Y))≦0.1 is satisfied.

[0018] This creates a curved surface that is highly symmetrical with respect to the Z axis, and suppresses localized and irregular changes in the height direction of the cross-sectional curve over the entire surface, thereby preventing the occurrence of hot spots.

[0019] (6) In the electrode-embedded member of the present invention, when the quadratic coefficient of the first approximation formula is a(X) and the quadratic coefficient of the second approximation formula is a(Y), the absolute values ​​of a(X) and a(Y) are 4×10 -4 The present invention is characterized in that:

[0020] This makes it easier to control the temperature distribution and suppress the occurrence of hot spots when the electrode-embedded member is used as a two-zone heater in which the electrodes can be controlled separately on the inside and outside of the base.

[0021] (7) The substrate holding member of the present invention is characterized by comprising an electrode-embedded member described in any one of (1) to (6) above, and a support member joined to the underside of the electrode-embedded member and supporting the electrode-embedded member.

[0022] This makes it possible to configure a substrate holding member using an electrode-embedded member that can reduce the occurrence of localized hot spots.

[0023] (8) Furthermore, a method for manufacturing an electrode-embedded member of the present invention is a method for manufacturing an electrode-embedded member, comprising the steps of: preparing a ceramic base having an electrode embedded therein and a plurality of pin-shaped protrusions formed on one main surface thereof; placing or adsorbing a substrate onto the plurality of pin-shaped protrusions and measuring the curved shape of the surface with a laser interferometer; polishing or grinding the plurality of pin-shaped protrusions so that the curved shape becomes a predetermined convex shape or concave shape that is approximately symmetrical about a central axis; and placing or adsorbing a substrate onto the plurality of pin-shaped protrusions after polishing or grinding, measuring the curved shape of the surface with a laser interferometer, and confirming that the curved shape becomes the predetermined convex shape or concave shape.

[0024] In this way, by polishing or grinding the multiple pin-shaped protrusions so that the curved shape when the substrate is placed on it has a specified convex or concave shape, the substrate can better conform to the pin-shaped protrusions than by increasing the flatness of the curved shape to make it closer to a plane, and an electrode-embedded member can be produced that can reduce the occurrence of localized hot spots.

[0025] (9) The manufacturing method of the electrode-embedded member of the present invention is a manufacturing method of the electrode-embedded member, The present invention relates to a method for manufacturing a ceramic substrate having an electrode embedded therein and a plurality of pin-shaped protrusions formed on one of its main surfaces, the method comprising the steps of: placing or sucking a substrate on the plurality of pin-shaped protrusions and measuring the curved shape of the surface with a laser interferometer; and, for a cross-sectional curve obtained by cutting the measured curved shape at a cross section passing through the Z axis with the Z axis as the center axis, defining the intersection line between a predetermined reference plane and the cross section as the X axis, defining the reference length in the X-axis direction as L (mm), defining the value of Z (mm) for a certain X (mm) as Z(X), and defining the value of deviation ΔZ(X) as ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2), and defining the maximum value of ΔZ(X) as ΔZ(X). max , the minimum value of ΔZ(X) is ΔZ(X) min Then, ΔZ(X)max -ΔZ(X) min The method is characterized by including the steps of: polishing or grinding the plurality of pin-shaped protrusions so as to satisfy the relationship ≦1 (μm); and placing or adsorbing a substrate onto the plurality of pin-shaped protrusions after polishing or grinding, measuring the curved shape of the surface with a laser interferometer, and verifying that the curved shape satisfies the specified relationship.

[0026] In this way, by polishing or grinding the multiple pin-shaped protrusions so that the curved shape when the substrate is placed on it satisfies a specified relationship, the substrate can better conform to the pin-shaped protrusions than if the curved shape was made more flat to make it closer to a plane, and an electrode-embedded member can be manufactured that can reduce the occurrence of localized hot spots. Effect of the Invention

[0027] According to the present invention, it is possible to reduce the occurrence of localized hot spots. In addition, since the substrate is supported by the pin-shaped protrusions, it is possible to suppress the inclusion of particles, and the space below the substrate can be used as a gas flow path as necessary. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic cross-sectional view showing an example of an electrode-embedded member according to a first embodiment of the present invention. [Diagram 2] 3 is a schematic diagram showing an example of the upper surface of an electrode-embedded member according to the first embodiment. FIG. [Diagram 3] 1 is a schematic partial cross-sectional view showing an example of an electrode-embedded member according to a first embodiment. [Figure 4] FIG. 4 is a schematic partial cross-sectional view for determining a deviation ΔZ(X) at a certain point X in the example of FIG. 3. [Diagram 5] 5A to 5C are schematic diagrams showing modified examples of the upper surface of the electrode-embedded member according to the first embodiment. [Figure 6] 4 is a schematic partial cross-sectional view showing a modified example of an electrode-embedded member according to the first embodiment. FIG. [Figure 7]4 is a schematic partial cross-sectional view showing a modified example of an electrode-embedded member according to the first embodiment. FIG. [Figure 8] 4 is a schematic partial cross-sectional view showing a modified example of an electrode-embedded member according to the first embodiment. FIG. [Figure 9] 1 is a schematic cross-sectional view showing an example of a substrate holding member according to a first embodiment. [Figure 10] FIG. 6 is a schematic cross-sectional view showing an example of an electrode-embedded member according to a second embodiment of the present invention. [Figure 11] 13(a) and 13(b) are graphs showing the measurement results in the X-axis direction and the Y-axis direction of the substrate surface of the substrate holding member of Example 1, respectively. [Figure 12] 13(a) and 13(b) are graphs showing the measurement results in the X-axis direction and the Y-axis direction of the substrate surface of the substrate holding member of Comparative Example 1, respectively. [Figure 13] 13(a) and 13(b) are graphs showing the deviation ΔZ(X) values ​​for cross-sectional curves in the X-axis direction of Example 1 and Comparative Example 1, respectively. [Figure 14] 6(a) and 6(b) are graphs showing the temperature distributions of the substrates of Example 1 and Comparative Example 1, respectively. [Figure 15] FIG. 11 is a schematic cross-sectional view showing a substrate holding member according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are used for the same components in each drawing, and duplicated descriptions will be omitted. In the configuration diagrams, the size of each component is conceptually shown, and does not necessarily represent the actual dimensional ratio.

[0030] [First embodiment] (Configuration of electrode embedding member) An electrode-embedded member according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4. Fig. 1 is a schematic cross-sectional view showing an example of an electrode-embedded member according to the first embodiment of the present invention. Fig. 2 is a schematic view showing an example of the upper surface of an electrode-embedded member according to the first embodiment. Fig. 3 is a schematic partial cross-sectional view showing an example of an electrode-embedded member according to the first embodiment. Fig. 4 is a schematic partial cross-sectional view for determining a deviation ΔZ(X) at a certain X in the example of Fig. 3. The terminal 50 and the terminal hole 52 are omitted in the partial cross-sectional view. The electrode-embedded member 100 according to this embodiment includes a base 10, an electrode 20, and a pin-shaped protrusion 30.

[0031] The base 10 is made of a ceramic sintered body and is formed into a substantially flat plate shape. The base 10 may be a substantially circular plate shape, or may be a polygonal plate shape, an elliptical plate shape, or any other shape. The substantially flat plate shape includes a convex shape or a concave shape, which will be described later. The base 10 has a shape in which the center 16 of the base is naturally determined.

[0032] The electrode 20 is embedded in the base 10. The electrode 20 is used as a heater electrode for heating the substrate (wafer) W. An electrode used for other purposes, such as an electrostatic attraction electrode or a high-frequency electrode, may also be embedded.

[0033] A plurality of pin-shaped protrusions 30 are formed to protrude upward from the upper surface 12 of the base 10. The shape of the pin-shaped protrusions 30 is appropriately selected from among columnar shapes such as a cylindrical shape or a rectangular columnar shape, pyramidal shapes such as a conical shape or a pyramidal shape, and shapes in which the top of a pyramidal shape such as a truncated cone shape or a truncated pyramidal shape is cut off.

[0034] The arrangement of the pin-shaped protrusions 30 is not particularly limited. It may be in a known form or a similar form, and may be, for example, a regular arrangement such as concentric circles as shown in Fig. 2, a square lattice or triangular lattice as shown in Fig. 5, or an irregular arrangement with localized sparse and dense portions. Fig. 5 is a schematic diagram showing a modified example of the upper surface of the electrode-embedded member according to the first embodiment.

[0035] The upper ends 32 of the pin-shaped protrusions as a whole form a curved surface (curved mounting surface) of a predetermined shape on which the substrate W is placed. As a result, the pin-shaped protrusions 30 support the substrate W. That is, the curved mounting surface formed by the upper ends 32 of the pin-shaped protrusions is determined. As a result, the upper ends 32 of the pin-shaped protrusions come into contact with the substrate W, and the substrate W is supported. Note that some of the pin-shaped protrusions 30 may not have their upper ends in contact with the substrate W. This is because, even if such protrusions exist, the substrate W can be supported depending on the arrangement of the surrounding pin-shaped protrusions 30. Note that, although the entire upper ends 32 of the pin-shaped protrusions come into contact with the substrate W in FIG. 3, only a part of the upper ends 32 of the pin-shaped protrusions may come into contact with the substrate W.

[0036] A cross-sectional curve 42 obtained by cutting the mounting surface formed by upper ends 32 of the multiple pin-shaped protrusions at a cross section passing through the central axis of base 10 (a straight line passing through center 16 of base and perpendicular to the reference plane of base 10) as the Z axis is a curve that has a maximum value of Z near the central axis and monotonically decreases toward the outer periphery 18 of base 10 as shown in Fig. 3, or a curve that has a minimum value of Z near the central axis and monotonically increases toward the outer periphery 18 of base 10 as shown in Fig. 6, when the intersection line between a predetermined reference plane and the cross section is the X axis. Fig. 6 is a partial cross-sectional view showing a modified example of an electrode-embedded member according to the first embodiment.

[0037] The predetermined reference plane may be the upper surface 12 of the substrate 10 when the substrate 10 is placed on a horizontal surface and the upper surface 12 is horizontal as shown in FIG. 3 or FIG. 6, or may be a horizontal plane passing through a point on the upper surface 12 of the substrate 10 that is closest to the horizontal surface when the substrate 10 is placed on a horizontal surface and the upper surface 12 is not horizontal as shown in FIG. 7 or FIG. 8. The reference plane may be a plane obtained by translating these horizontal planes upward or downward. FIGS. 7 and 8 are partial cross-sectional views showing modified examples of the electrode-embedded member according to the first embodiment. The vicinity of the central axis refers to a range within 25 mm from the central axis.

[0038] In this way, by having cross-sectional curve 42 of the mounting surface be a curve that has a maximum value of Z near the central axis and monotonically decreases toward the outer periphery 18 of base 10, or a curve that has a minimum value of Z near the central axis and monotonically increases toward the outer periphery 18 of base 10, the ability of substrate W to conform to pin-shaped protrusions 30 is improved and the occurrence of localized hot spots can be reduced compared to increasing the flatness of the mounting surface to make it closer to a plane. Furthermore, since substrate W is supported by pin-shaped protrusions 30, it is possible to suppress particle entrapment and, if necessary, the space below substrate W can be used as a gas flow path.

[0039] As for the shapes of the base 10 and the multiple pin-shaped protrusions 30, it is preferable that the base 10 is flat as shown in Fig. 3, the multiple pin-shaped protrusions 30 are formed so as to have different heights from the reference plane, and a mounting curved surface is formed by the multiple pin-shaped protrusions 30. This makes it easy to process the mounting curved surface, and also makes it possible to select one from multiple mounting curved surface shapes when grinding and polishing the pin-shaped protrusions 30.

[0040] On the other hand, the shape of the base 10 and the multiple pin-shaped protrusions 30 may be such that the upper surface 12 of the base 10 is formed with substantially the same curved surface as the mounting curved surface, and the mounting curved surface is formed by the multiple pin-shaped protrusions 30 formed with substantially the same height from the upper surface 12 of the base 10, as shown in Fig. 7. This makes it possible to make the chucking force uniform when the electrode-embedded member 100 is used as a member that chutes the substrate W. Even with the shape of Fig. 3, the difference in height of the protrusions 30 in the Z-axis direction is slight, so there is no effect on the chucking force of the substrate W itself.

[0041] Furthermore, the shape of the base 10 may be such that the lower surface 14 of the base 10 is formed with substantially the same curved surface as the curved surface on which it is placed, as shown in Fig. 8. Furthermore, the electrode 20 embedded in the base 10 may be formed with substantially the same curved surface as the curved surface on which it is placed, as shown in Fig. 8. Thus, the base 10 being substantially flat includes not only the convex shape shown in Fig. 3 or Fig. 6, but also the convex shape shown in Fig. 7 or Fig. 8, or the concave shape not shown.

[0042] The placement curved surface can be measured by a three-dimensional measuring device. However, it is important that when the substrate W is placed or sucked on the electrode-embedded member 100, the substrate W follows the placement curved surface, and the shape of the surface of the substrate W opposite the placement curved surface (the surface of the substrate W) is an ideal curved surface. For this reason, the curved surface measured by a laser interferometer on the surface opposite the placement curved surface when a silicon wafer with a thickness of 0.775 mm is placed or sucked is regarded as the placement curved surface. The same applies to the cross-sectional curve 42.

[0043] As shown in FIG. 4, the cross-sectional curve 42 is expressed as follows: the reference length in the X-axis direction is L (mm), the value of Z (mm) for a certain X (mm) is Z(X), and the value of deviation ΔZ(X) is ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2), where the maximum value of ΔZ(X) is ΔZ(X). max , the minimum value of ΔZ(X) is ΔZ(X) min Then, ΔZ(X) max -ΔZ(X) min ≦1 (μm), and more preferably 0.5 μm or less. Here, X is defined in an area at least L inward from the outer edge of the area where the substrate of the electrode-embedded member is placed, and is preferably calculated in an area 2L inward from the outer edge of the area. This suppresses local unevenness, so that the occurrence of local hot spots can be further reduced. FIG. 4 is a schematic partial cross-sectional view for determining the deviation ΔZ(X) at a certain X in the example of FIG. 3. The reference length L can be the arrangement pitch of the pin-shaped protrusions 30. For example, when the pin-shaped protrusions 30 are arranged in a concentric circle, the difference in the radii of the concentric circles can be applied. When a plurality of pin-shaped protrusions 30 are arranged at a constant interval, the reference length L is preferably the interval. FIG. 6 shows such an example.

[0044] The flatness of the curved mounting surface is preferably 50 μm or less. This allows the substrate W to be mounted without wrinkling. The flatness of the curved mounting surface is the difference between the maximum and minimum Z values ​​for all points on the curved mounting surface. The lower limit of the flatness differs depending on the diameter of the base 10 and the shape of the target curved mounting surface, but is preferably, for example, 5 μm or more.

[0045] In addition, when the curve obtained by cutting the mounting surface at a second cross section perpendicular to the X-axis and including the Z-axis is taken as the second cross section curve, and the intersection line between a predetermined reference plane and the second cross section is taken as the Y-axis, the coefficient of determination R for the first approximation equation when the cross section curve is approximated by a quadratic curve is 2 , and the coefficient of determination R for the second approximation equation when the second profile curve is approximated by a quadratic curve. 2 It is preferable that both are 0.99 or more. This allows the cross-sectional curves in the X-axis and Y-axis directions to have a quadratic curve shape, and local and irregular changes in the height direction of the cross-sectional curve can be suppressed, thereby further reducing the occurrence of local hot spots. 2 To calculate the regression sum of squares, divide the regression sum of squares by the total sum of squares. The regression sum of squares is the sum of squared deviations of the predicted values ​​of the response variable, and the total sum of squares is the sum of squared deviations of the observed values ​​of the response variable.

[0046] Furthermore, when the units of Z are μm, and the units of X and Y are mm, the quadratic coefficient of the first approximation formula is a(X) and the quadratic coefficient of the second approximation formula is a(Y), it is preferable to satisfy 2(a(X)-a(Y)) / (a(X)+a(Y))≦0.1. This forms a curved surface with good symmetry with respect to the Z axis, and local and irregular changes in the height direction of the cross-sectional curve can be suppressed over the entire surface, thereby suppressing the occurrence of hot spots. Note that a(X) and a(Y) have the same positive and negative values.

[0047] The height of the pin-shaped protrusions 30 is preferably 50 μm or more and 500 μm or less. The height of the pin-shaped protrusions 30 refers to the distance from the reference plane of the substrate 10 to the upper ends 32 of the pin-shaped protrusions. The upper ends 32 of the pin-shaped protrusions are preferably flat with a predetermined size. In this case, the maximum diameter of the flat surface of the upper ends 32 of the pin-shaped protrusions is preferably 100 μm or more and 300 μm or less. The surface roughness of the flat surface of the upper ends 32 of the pin-shaped protrusions is preferably Ra 0.01 μm or more and 0.50 μm or less.

[0048] The electrode-embedded member 100 may also be provided with terminals 50, terminal holes 52, lift pin holes (not shown), and, when used as a vacuum chuck, ventilation holes for that purpose, an annular protrusion, and the like.

[0049] (Configuration of the substrate holding member) Next, the configuration of the substrate holding member according to the first embodiment will be described. Fig. 9 is a cross-sectional view showing an example of the substrate holding member according to this embodiment. The substrate holding member 150 according to this embodiment includes an electrode-embedding member 100 and a support member 110. The basic configuration of the electrode-embedding member 100 is as described above.

[0050] The support member 110 is made of a ceramic sintered body and supports the electrode-embedded member 100. This allows the substrate holding member 150 to be used in a heater with a shaft, an electrostatic chuck with a shaft, or the like. The support member 110 is bonded to a predetermined position on the lower surface of the electrode-embedded member 100 via a bonding surface 112. The bonding may be solid-state bonding or bonding using a bonding material. The support member 110 is preferably formed of a ceramic sintered body having the same main component as the base 10 of the electrode-embedded member 100.

[0051] [Second embodiment] 10 is a cross-sectional view showing an example of an electrode-embedded member according to a second embodiment of the present invention. The electrode-embedded member 200 according to this embodiment has a basic configuration similar to that of the electrode-embedded member 100 according to the first embodiment, so only the differences will be described below.

[0052] The electrode-embedded member 200 according to this embodiment is a so-called two-zone heater in which different inner electrodes 22 and outer electrodes 24 are embedded in two regions, an inner region including at least the center 16 of the base and an outer region from the top surface 12 of the base 10 excluding the inner region, and the electrodes can be controlled for each region. Note that the number of regions may be three or more.

[0053] In this case, when the unit of Z is μm, the unit of X and Y is mm, the quadratic coefficient of the first approximation formula described in the first embodiment is a(X), and the quadratic coefficient of the second approximation formula is a(Y), the absolute values ​​of a(X) and a(Y) are 4×10 -4 It is preferable that the temperature is equal to or higher than the above. This makes it easier to control the temperature distribution and suppress the occurrence of hot spots when the electrode-embedded member 200 is used as a two-zone heater in which the electrodes can be controlled separately inside and outside the substrate. The upper limit of the absolute values ​​of a(X) and a(Y) varies depending on the diameter of the substrate 10 and the target flatness, but is, for example, 2.2×10 -3 It is preferable that:

[0054] (Configuration of the substrate holding member) Next, the configuration of the substrate holding member according to the second embodiment will be described. The substrate holding member according to this embodiment has the same configuration as the substrate holding member according to the first embodiment, except that the electrode-embedded member joined to the support member is the above-mentioned two-zone heater. Therefore, the description will be omitted.

[0055] [Method of manufacturing electrode-embedded members] Next, a manufacturing method of the electrode-embedded member according to the first and second embodiments will be described. The electrode-embedded member according to the embodiment is manufactured, for example, by a powder hot pressing method. The powder hot pressing method is a method in which ceramic raw material powder and a predetermined electrode are alternately stacked to embed the electrodes inside the ceramic, and then uniaxial hot pressing and firing the resulting material. By employing the powder hot pressing method, the member can be manufactured in a short period of time. Note that the manufacturing method is not limited to this method, and may be, for example, a molded body hot pressing method disclosed in Japanese Patent No. 6148845, a conventional green sheet lamination method, or the like.

[0056] For example, additives such as sintering aids, binders, plasticizers, and dispersants are appropriately added to and mixed with ceramic powder to prepare ceramic raw material powder (slurry), and the granulated powder is granulated by a spray-drying method or the like. The mixing method may be either wet or dry, and a mixer such as a ball mill or a vibration mill may be used. Silicon carbide, aluminum oxide, aluminum nitride, silicon nitride, and the like are used as the raw ceramic powder.

[0057] The ceramic powder is preferably of high purity, and the purity is preferably 96% or more, more preferably 98% or more. The average particle size of the ceramic powder varies depending on the type of ceramic powder used as a raw material, but is preferably 0.1 μm to 1.0 μm, and more preferably 0.3 μm to 0.8 μm.

[0058] The material of the electrodes embedded in the ceramic sintered compact is preferably Mo or W.

[0059] Sintering can be performed by uniaxial hot press sintering or atmospheric sintering. In uniaxial hot press sintering, the granulated powder forming the substrate is filled into a bottomed carbon mold, and the electrodes cut into a predetermined shape after uniaxial pressing are placed on the compact. The same granulated powder is filled on top of the granulated powder, and a carbon punch is placed on top to form the electrode. It is preferable to perform hot press sintering at a temperature of 1700°C to 2000°C and a pressure of 1 MPa to 20 MPa for 0.1 hours to 20 hours.

[0060] After firing, the process includes forming a plurality of pin-shaped protrusions, processing the back surface, forming terminal holes, and grinding and polishing to a predetermined shape. The formation method can be blasting, milling, laser processing, etc. If necessary, ventilation holes, annular protrusions, etc. can be formed. This makes it possible to prepare a ceramic base having electrodes embedded therein and a plurality of pin-shaped protrusions formed on one of its main surfaces.

[0061] Next, the substrate W is placed or sucked on the pin-shaped protrusions, and the curved shape of the surface (the curved shape of the surface) is measured by a laser interferometer. If the measurement result shows that the curved shape is a predetermined convex or concave shape that is approximately symmetrical about the central axis, the processing is terminated. If the measurement result shows that the curved shape is not a predetermined convex or concave shape that is approximately symmetrical about the central axis, the pin-shaped protrusions are polished or ground so that the curved shape becomes a predetermined convex or concave shape that is approximately symmetrical about the central axis. Then, the substrate is placed or sucked on the pin-shaped protrusions after polishing or grinding, and the curved shape of the surface is measured by a laser interferometer to confirm that the curved shape becomes the predetermined convex or concave shape. By repeating these steps, the curved shape is processed into a desired shape. The term "a curved surface shape is a predetermined convex or concave shape that is approximately symmetrical about a central axis" means that any cross-sectional curve of the measured curved surface shape is a curve that has a maximum value of Z near the central axis and monotonically decreases toward the periphery of the base, or a curve that has a minimum value of Z near the central axis and monotonically increases toward the periphery of the base.

[0062] When the substrate W is placed or sucked onto a plurality of pin-shaped convex portions and the curved shape of the surface (mounted curved shape) is measured by a laser interferometer, the target curved shape is a cross-sectional curve cut at a cross section passing through the Z axis with the central axis as the Z axis, the intersection line between a predetermined reference plane and the cross section is the X axis, the reference length in the X-axis direction is L (mm), the value of Z (mm) for a certain X (mm) is Z(X), the value of deviation ΔZ(X) is ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2), and the maximum value of ΔZ(X) is ΔZ(X). max , the minimum value of ΔZ(X) is ΔZ(X) min Then, ΔZ(X) max -ΔZ(X) min ≦1 (μm). In this case, the process of polishing or grinding the multiple pin-shaped protrusions is also performed with that shape as the target. Also, a shape that includes both features or other features may be the target.

[0063] Finally, the terminals are connected to the terminal holes with brazing material etc. The terminals can be made of Ni etc. The brazing material can be Au brazing material etc.

[0064] In this manner, the electrode-embedded member according to the embodiment of the present invention can be manufactured.

[0065] [Method of manufacturing the substrate holding member] The ceramic powder is granulated to form a ceramic molded body that will become the support member after firing. The ceramic powder preferably has the same main component as the ceramic powder used in the electrode-embedded member.

[0066] Next, the ceramic molded body is degreased at a predetermined temperature or more for a predetermined time or more to produce a ceramic degreased body. For example, the ceramic molded body is heat treated at a temperature of 400°C to 800°C to produce a ceramic degreased body. The degreasing time is preferably 1 hour to 120 hours. For degreasing, an atmospheric furnace or a nitrogen atmosphere furnace can be used, but an atmospheric furnace is preferable.

[0067] Next, the ceramic degreased body is fired to fire the support member that supports the electrode-embedded member. The firing of the support member is preferably performed at normal pressure. The firing temperature is preferably 1500°C or higher and 2000°C or lower. The firing time is preferably 1 hour or higher and 12 hours or lower. The firing atmosphere is, for example, a nitrogen or inert gas atmosphere, but may also be a vacuum atmosphere.

[0068] Then, the support member is placed at a predetermined position on the lower surface of the electrode-embedded member, and the electrode-embedded member and the support member are bonded together by applying pressure perpendicular to the bonding surface while heating. The pressure is preferably 1 MPa or more. The heating temperature is preferably 1500°C or more and 2000°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 results in a solid-state bond between the substrate holding member body and the support member. The bonding means is not limited to solid-state bonding, and may also be a means in which an inorganic bonding material is interposed.

[0069] The formation of the pin-shaped protrusions of the electrode-embedding member, polishing or grinding of the pin-shaped protrusions, brazing of the terminals, etc. are preferably carried out after joining the electrode-embedding member and the support member.

[0070] In this manner, a substrate holding member according to an embodiment of the present invention in which an electrode-embedded member and a support member are joined can be manufactured.

[0071] [Examples and Comparative Examples] Example 1 Example 1 is a substrate holding member having a convex curved mounting surface as shown in FIG. 9. The material of the base and the support member is a sintered body mainly composed of aluminum nitride (AlN). A base (electrode-embedded member) in which a substantially disk-shaped electrode with a diameter of φ300 mm and a thickness of t25 mm is embedded and a support member are prepared, and after joining with the support member, multiple pin-shaped protrusions are formed by blasting. The multiple pin-shaped protrusions are formed in a concentric pattern of φ1 mm in an area within φ298 mm from the center of the base, with a height of 50 μm from the reference plane.

[0072] Next, the pin-shaped protrusions were polished to create a convex mounting surface. Starting from the outer periphery of the pin-shaped protrusions, the protrusions were lapped with free abrasive grains to reduce the height by a maximum of 10 μm, creating a convex mounting surface. The surface roughness Ra of the multiple pin-shaped protrusions was set to 0.05 μm.

[0073] In other words, the substrate holding member of Example 1 is a substrate holding member that has been processed so that a cross-sectional curve obtained by cutting the curved mounting surface formed by the upper ends of the pin-shaped convex portions at a cross section passing through the Z axis, with the central axis of the base being the Z axis, is a curve that has a maximum Z value near the central axis and monotonically decreases toward the outer periphery of the base, when the intersection line between a predetermined reference plane and the cross section is the X axis.

[0074] Comparative Example 1 Comparative Example 1 is a conventional substrate holding member having a flat curved mounting surface as shown in Fig. 15. The substrate holding member was produced under the same conditions as in Example 1, and the polishing of the pin-shaped protrusions was adjusted to increase the flatness of the curved mounting surface (flat mounting surface). Fig. 15 is a schematic cross-sectional view showing the conventional substrate holding member.

[0075] (Measuring method for the curved surface) A substrate (silicon wafer) having a diameter of 300 mm and a thickness of 0.775 mm was placed on the substrate holding member obtained in Example 1 and Comparative Example 1, and the surface (surface of the substrate) opposite to the curved surface was measured by a laser interferometer. Figures 11(a) and 11(b) are graphs showing the measurement results in the X-axis direction and the Y-axis direction of the substrate surface of the substrate holding member of Example 1, respectively. Also, Figures 12(a) and 12(b) are graphs showing the measurement results in the X-axis direction and the Y-axis direction of the substrate surface of the substrate holding member of Comparative Example 1, respectively. Note that the predetermined reference plane in the examples and comparative examples is the predetermined reference plane in Figure 1 translated upward. Therefore, there is a range in which the value of Z is negative. These graphs can be interpreted as showing the cross-sectional curves in the X-axis direction and the Y-axis direction of the curved surface of the substrate holding member of Example 1 and Comparative Example 1, respectively.

[0076] The flatness of the curved surface of Example 1 was 10 μm, whereas the flatness of the curved surface of Comparative Example 1 was 3.5 μm. On the other hand, as can be seen by comparing the graphs of FIG. 11 and FIG. 12, Example 1 had a larger flatness than Comparative Example 1, but the local unevenness was smaller. This is considered to be because, when processing is performed for the purpose of reducing the overall flatness as in Comparative Example 1, the parts with poor flatness are polished intensively, and the boundary between the part polished intensively and the part not polished much is not polished any further if it is within a predetermined range. It is also presumed that further polishing to reduce the unevenness of this boundary will worsen the overall flatness.

[0077] On the other hand, when processing is performed for the purpose of smoothing the mounting surface to a convex or concave shape without placing emphasis on overall flatness, as in the present invention, polishing is performed continuously from the outer periphery to the inner periphery or from the inner periphery to the outer periphery, so it is thought that there will be almost no boundary between the parts that have been polished intensively and the parts that have not been polished much.

[0078] 13(a) and (b) are graphs showing the values ​​of deviation ΔZ(X) for the cross-sectional curves in the X-axis direction of Example 1 and Comparative Example 1, respectively. Each shows values ​​calculated in the range of -139.5 (mm)≦X≦139.5 (mm) where the reference length in the X-axis direction is L=9.5 mm, Z(X) is the value of Z (mm) for a certain X (mm), and ΔZ(X) is the value of deviation ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2).

[0079] According to this graph, it was found that the deviation ΔZ(X), which indicates local unevenness, is smaller in Example 1 than in Comparative Example 1. In addition, the maximum value of ΔZ(X) is max , the minimum value of ΔZ(X) is ΔZ(X) min In this case, in Example 1, ΔZ(X) max -ΔZ(X) min ≦1 (μm), but Comparative Example 1 did not.

[0080] (Evaluation method) The substrate was placed on the substrate holder of Example 1 and Comparative Example 1, and a voltage was applied to the internal electrode to set the temperature of the center of the substrate to 400°C and control the temperature. At this time, the temperature distribution of the substrate was measured along the X-axis using an infrared camera. Figures 14(a) and (b) are graphs showing the temperature distribution of the substrate of Example 1 and Comparative Example 1, respectively. When the graphs show a peak-shaped portion, it was determined that a hot spot occurred according to the size of the peak. The graph of Figure 14 shows the temperature distribution in the range from -100 mm to +100 mm. This is because the influence of scattering, etc. is large in the outer periphery, which is far from the infrared camera, and the deviation between the measured temperature of the infrared camera and the actual temperature may become large.

[0081] (Evaluation Results) A relatively small peak was observed near the center in Example 1. On the other hand, a large hot spot occurred near the center in Comparative Example 1. In other words, it was confirmed that the substrate holding member of the present invention suppresses the occurrence of hot spots.

[0082] Next, the approximation formula was calculated when the cross-sectional curves of Example 1 and Comparative Example 1 were approximated by a quadratic curve when the unit of Z was μm and the units of X and Y were mm. The first approximation formula when the cross-sectional curve in the X-axis direction of the example was approximated by a quadratic curve was Z=(4.598E-04)X 2 +(2.416E-03)X-(3.403E+00), and the coefficient of determination for this is R 2 was 0.9983. The second approximation equation for the Y-axis direction cross section (second cross section) is Z=(4.453E-04)Y 2 -(1.526E-03)Y+(3.296E+00), and the coefficient of determination for this is R 2 was 0.9972. That is, the coefficient of determination R 2 was confirmed to be 0.99 or higher.

[0083] On the other hand, the first approximation equation when the cross-sectional curve in the X-axis direction of Comparative Example 1 is approximated by a quadratic curve is Z=(9.232E-05)X 2 +(2.354E-04)X-(6.858E-01), and the coefficient of determination for this is R 2 was 0.8910. The second approximation equation for the Y-axis direction cross section (second cross section) is Z=(1.146E-04)Y 2 +(3.055E-04)Y-(8.462E-01), and the coefficient of determination for this is R 2 The coefficient of determination R 2 All were below 0.99.

[0084] Furthermore, for Example 1, when the quadratic coefficient of the first approximation equation is a(X) and the quadratic coefficient of the second approximation equation is a(Y), it was confirmed that 2(a(X)-a(Y)) / (a(X)+a(Y))≦0.1. This confirmed that the substrate holding member of the example has a curved surface that is symmetrical with respect to the Z axis. It is believed that this characteristic makes it possible to suppress localized and irregular changes in the height direction of the cross-sectional curve over the entire surface, thereby suppressing the occurrence of hot spots.

[0085] In addition, the absolute values ​​of a(X) and a(Y) in Example 1 are 4×10 -4 In contrast, Comparative Example 1 was 4 × 10 -4 It was less than.

[0086] Example 2 In Example 2, a substrate holding member was produced under the same conditions as in Example 1, except that the electrodes of the electrode-embedded member of Example 1 were a circular inner electrode with a diameter of 200 mm or less and a donut-shaped outer electrode with a diameter of 200 mm or more but no greater than 298 mm, forming a two-zone heater in which each electrode could be controlled separately.

[0087] Comparative Example 2 In Comparative Example 2, a substrate holding member was produced under the same conditions as in Comparative Example 1, except that the electrodes of the electrode-embedded member in Comparative Example 1 were replaced with a two-zone heater similar to that in Example 2.

[0088] In Example 2, the inner electrode and the outer electrode were controlled separately, thereby enabling control of the temperature distribution so that the surface temperature of the substrate gradually decreased from the inside to the outside of the substrate. In contrast, in Comparative Example 2, the inner electrode and the outer electrode were controlled separately to attempt to control the temperature distribution so that the surface temperature of the substrate gradually decreased from the inside to the outside of the substrate, but the temperature could only be controlled so that it rapidly decreased at the boundary between the inner electrode and the outer electrode.

[0089] In Example 2, the absolute values ​​of a(X) and a(Y) are 4×10 -4 In contrast, Comparative Example 2 was 4 × 10 -4In this way, it is considered that by having the absolute values ​​of a(X) and a(Y) of the cross-sectional curves be equal to or greater than a predetermined value, i.e., by having the radius of curvature of the mounting curved surface be equal to or less than a predetermined value, when the electrode-embedded member is used as a two-zone heater in which the electrodes can be controlled separately on the inside and outside of the base, it becomes easier to control the temperature distribution and the occurrence of hot spots can be suppressed.

[0090] From the above, it has been confirmed that the electrode embedding member and substrate holding member of the present invention can reduce the occurrence of localized hot spots, suppress the ingestion of particles, and, if necessary, can use the space under the substrate as a gas flow path.

[0091] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications and equivalents are included within the spirit and scope of the present invention. In addition, the structure, shape, number, position, size, etc. of the components shown in each drawing are for convenience of explanation and may be changed as appropriate. [Explanation of symbols]

[0092] 10 Base 12 Top side 14 Bottom side 16 Center of the base 18 Circumference 20 electrodes 22 Inner electrode 24 outer electrode 30 Pin-shaped protrusion 32 Upper end of pin-shaped protrusion 42 Section curve 50 Terminals 52 Terminal hole 100, 200 Electrode embedding material 110 Support member 112 Joint surface 150 Substrate holding member W substrate

Claims

1. An electrode embedding member, A base body formed of a ceramic sintered body; An electrode embedded in the substrate; a plurality of pin-shaped protrusions formed to protrude upward from the upper surface of the base, a cross-sectional curve obtained by cutting the mounting surface formed by the upper ends of the multiple pin-shaped convex portions at a cross section passing through the central axis of the base body as the Z-axis, is a curve that has a maximum Z value near the central axis and monotonically decreases toward the outer periphery of the base body, or a curve that has a minimum Z value near the central axis and monotonically increases toward the outer periphery of the base body, when an intersection line between a predetermined reference plane and the cross section is set as the X-axis; The cross-sectional curve is expressed by the following equation: the reference length in the X-axis direction is L (mm), the value of Z (mm) for a certain X (mm) is Z(X), and the value of deviation ΔZ(X) is ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2) With the maximum value of ΔZ(X) being ΔZ(X) max and the minimum value of ΔZ(X) being ΔZ(X) min , ΔZ(X) max - ΔZ(X) min ≦1(μm) An electrode-embedded member, comprising:

2. An electrode embedding member as described in claim 1, characterized in that the flatness of the mounting curved surface is 50 μm or less.

3. An electrode embedding member, A base body formed of a ceramic sintered body; An electrode embedded in the substrate; a plurality of pin-shaped protrusions formed to protrude upward from the upper surface of the base, a cross-sectional curve obtained by cutting the mounting surface formed by the upper ends of the multiple pin-shaped convex portions at a cross section passing through the central axis of the base body as the Z-axis, is a curve that has a maximum Z value near the central axis and monotonically decreases toward the outer periphery of the base body, or a curve that has a minimum Z value near the central axis and monotonically increases toward the outer periphery of the base body, when an intersection line between a predetermined reference plane and the cross section is set as the X-axis; an electrode-embedded member, characterized in that, when a curve obtained by cutting the mounting surface at a second cross section perpendicular to the X-axis and including the Z-axis is defined as a second cross-sectional curve, and an intersection line between the predetermined reference plane and the second cross section is defined as a Y-axis, a coefficient of determination R2 for a first approximation equation when the cross-sectional curve is approximated by a quadratic curve, and a coefficient of determination R2 for a second approximation equation when the second cross-sectional curve is approximated by a quadratic curve are both 0.99 or more.

4. When the quadratic coefficient of the first approximation equation is a(X) and the quadratic coefficient of the second approximation equation is a(Y), 2(a(X)-a(Y)) / (a(X)+a(Y))≦0.1 4. The electrode-embedding member according to claim 3, wherein the above-mentioned condition is satisfied.

5. The electrode-embedded member according to claim 3 or claim 4, characterized in that when the quadratic coefficient of the first approximation equation is a(X) and the quadratic coefficient of the second approximation equation is a(Y), the absolute values ​​of a(X) and a(Y) are 4×10-4 or more.

6. An electrode embedding member according to any one of claims 1 to 5, a support member joined to a lower surface of the electrode-embedded member and supporting the electrode-embedded member.

7. A method for manufacturing an electrode-embedded member, comprising the steps of: preparing a ceramic base having an electrode embedded therein and a plurality of pin-shaped protrusions formed on one of its main surfaces; a step of placing or sucking a substrate on the plurality of pin-shaped protrusions and measuring the curved surface shape of the substrate by a laser interferometer; a step of polishing or grinding the plurality of pin-shaped protrusions so that the curved surface shape has a predetermined convex or concave shape that is substantially symmetrical with respect to a central axis; a step of placing or sucking a substrate onto the plurality of pin-shaped convex portions after polishing or grinding, measuring the curved shape of the surface with a laser interferometer, and confirming that the curved shape is the specified convex shape or concave shape.

8. A method for manufacturing an electrode-embedded member, comprising the steps of: preparing a ceramic base having an electrode embedded therein and a plurality of pin-shaped protrusions formed on one of its main surfaces; a step of placing or sucking a substrate on the plurality of pin-shaped protrusions and measuring the curved surface shape of the substrate by a laser interferometer; The measured curved surface shape is cut at a cross section passing through the Z axis with the central axis as the Z axis, the intersection line between a predetermined reference plane and the cross section is the X axis, the reference length in the X axis direction is L (mm), the value of Z (mm) for a certain X (mm) is Z(X), and the value of deviation ΔZ(X) is ΔZ(X)=Z(X)-((Z(X+L)+Z(XL)) / 2) With the maximum value of ΔZ(X) being ΔZ(X) max and the minimum value of ΔZ(X) being ΔZ(X) min , ΔZ(X) max - ΔZ(X) min ≦1(μm) a step of polishing or grinding the plurality of pin-shaped protrusions so as to satisfy a step of placing or sucking a substrate onto the plurality of pin-shaped convex portions after polishing or grinding, measuring the curved shape of the surface with a laser interferometer, and verifying that the curved shape satisfies the specified relationship.

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