Wafer support and method for manufacturing the wafer support

Abstract

To provide a new wafer support capable of achieving a desired adsorption force. [Solution] The wafer support 10 comprises a base material 16 made of a ceramic sintered body and a conductive member 18 which is at least partially embedded in the base material. The base material 16 contains 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium in terms of zirconium oxide, and 0 to 0.48% by mass of yttrium or ytterbium in terms of yttrium oxide or ytterbium oxide.

Description

Technical Field

[0001] The present invention relates to a support for supporting a wafer.

Background Art

[0002] Conventionally, electrostatic chucks for holding a semiconductor wafer or controlling the temperature of a semiconductor wafer have been used in various semiconductor processes. The materials used for electrostatic chucks vary depending on the environment in which they are used and the required characteristics. For example, an electrostatic chuck made of ceramics mainly composed of alumina is known from the viewpoints of plasma resistance, high withstand voltage, high strength, and high dielectric constant (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, a process for forming a memory device having a multilayer structure such as 3D-NAND on a wafer has been developed. In such a process, the warpage of the wafer becomes larger than before. Therefore, an electrostatic chuck that generates an adsorption force for firmly holding a wafer with a large warpage is required. In addition, depending on the manufacturing process, helium gas with a high gas pressure may be supplied to the back surface of the wafer to ensure uniform heat distribution throughout the wafer, and an electrostatic chuck that generates an adsorption force to prevent the wafer from floating due to the gas is required.

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide a new wafer support capable of realizing a desired adsorption force.

Means for Solving the Problems

[0006] To solve the above problems, a wafer support according to one embodiment of the present invention comprises a substrate made of a ceramic sintered body and a conductive member that is at least partially embedded in the substrate. The substrate contains 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium in terms of zirconium oxide, and 0 to 0.48% by mass of yttrium or ytterbium in terms of yttrium oxide or ytterbium oxide.

[0007] According to this embodiment, the inclusion of zirconium oxide, yttrium oxide, or ytterbium oxide is expected to increase the dielectric constant and improve adsorption capacity.

[0008] The base material may further contain at least one of the following: (1) magnesium in the form of 0.29 to 0.73% by mass, (2) calcium in the form of 0.1 to 0.2% by mass, or (3) silicon in the form of 0 to 0.15% by mass, (3) silicon in the form of 0% by mass. This enables low-temperature sintering and densification while suppressing the grain growth of aluminum oxide.

[0009] The DC dielectric breakdown voltage of the ceramic sintered body may be 100kV / mm or higher. This allows for an increase in the voltage applied to the conductive member, thereby improving the adsorption force.

[0010] The porosity of the ceramic sintered body obtained by the mercury intrusion method may be 1.0% or less. This makes the ceramic sintered body denser and improves the dielectric breakdown voltage.

[0011] The average particle size D50 of the ceramic sintered body may be 0.7 to 1.5 μm. This allows for the creation of a dense ceramic sintered body.

[0012] The bending strength of the ceramic sintered body may be 600 MPa or higher. This makes it less likely for deformation or breakage to occur even when the dielectric layer is made thinner to improve the adsorption force.

[0013] The relative permittivity of the ceramic sintered body may be 10.0 or higher. This can improve the adsorption force.

[0014] The wafer may further include a metal plate on which the substrate is mounted. The metal plate may have channels formed therein for the flow of a cooling substance. This allows it to be used in vacuum processes where uniform temperature across the entire wafer surface is required, such as dry etching.

[0015] The system may further include a gas supply path for supplying gas between the substrate and the wafer mounted on the substrate. This allows the back side of the wafer to be cooled with gas.

[0016] Another aspect of the present invention is a method for manufacturing a wafer support. This manufacturing method includes the steps of: preparing a raw material powder containing 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium oxide, and 0 to 0.48% by mass of yttrium oxide or ytterbium oxide; arranging the raw material powder in a space of a predetermined shape; and firing the raw material powder by pressurizing the space in the range of 20 to 50 MPa and heating it in the range of 1350 to 1650°C.

[0017] According to this embodiment, a wafer support capable of achieving the desired adsorption force can be manufactured.

[0018] Furthermore, any combination of the above components, and any conversion of the expression of the present invention between methods, apparatus, systems, etc., are also valid embodiments of the present invention. In addition, combinations of the above-mentioned elements as appropriate may also be included within the scope of the invention for which patent protection is sought in this patent application. [Effects of the Invention]

[0019] According to the present invention, a desired adsorption force can be achieved. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic cross-sectional view of an electrostatic chuck placed inside an etching chamber. [Figure 2] It is a perspective view of an electrostatic chuck according to this embodiment. [Figure 3] It is a flowchart for explaining a method of manufacturing a wafer support according to this embodiment. [Figure 4] Fig. 4(a) is a graph showing the relationship between the content of zirconium oxide and the breakdown voltage, Fig. 4(b) is a graph showing the relationship between the content of ytterbium oxide and the breakdown voltage, and Fig. 4(c) is a graph showing the relationship between the content of magnesium oxide and the breakdown voltage. [Figure 5] Fig. 5(a) is a graph showing the relationship between the content of calcium oxide and the breakdown voltage, and Fig. 5(b) is a graph showing the relationship between the content of silicon oxide and the breakdown voltage.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted as appropriate.

[0022] (Wafer Support) First, the schematic configuration of the wafer support will be described. The wafer support only needs to be able to support a semiconductor substrate such as a silicon wafer, and may be provided with a suction mechanism and a temperature adjustment mechanism. Further, the wafer support functions as an electrostatic chuck that generates an adsorption force on the mounted wafer.

[0023] Hereinafter, a case where the wafer support is an electrostatic chuck provided with a cooling mechanism will be described as an example. Fig. 1 is a schematic cross-sectional view of an electrostatic chuck disposed in an etching chamber. Fig. 2 is a perspective view of the electrostatic chuck according to this embodiment.

[0024] The etching apparatus 100, including the chamber 12 shown in Figure 1, is a semiconductor manufacturing apparatus for etching the surface of a wafer W, such as silicon, which is a semiconductor substrate, using plasma P. A wafer support 10, which functions as an electrostatic chuck, is used to support the wafer W within the chamber 12. An upper electrode 14 for generating plasma P is also provided inside the chamber 12.

[0025] The wafer support 10 comprises a base material 16 made of a ceramic sintered body and a conductive member 18 in which at least a portion is embedded within the base material 16. The wafer W is mounted on the mounting surface 16a, which is the surface of the base material 16. The conductive member 18 functions as an electrostatic chuck electrode to which a voltage V is applied that generates an adsorption force for fixing the wafer W to the mounting surface 16a. In the wafer support 10 according to this embodiment, the conductive member 18 is embedded in the base material 16, which is a sintered body. Therefore, the conductive member 18 needs to be located inside the raw material powder during the firing stage, and it is preferable that it be a high-melting-point metal that does not melt at the firing temperature. For example, as the material of the conductive member, high-melting-point metals such as molybdenum, tungsten, and tantalum, or alloys containing two or more of these, are preferred.

[0026] Furthermore, the wafer support 10 has a gas supply channel 20 that extends from the mounting surface 16a exposed to the chamber side, through the interior of the substrate 16, to an external gas supply source (not shown). The gas supply channel 20 is for supplying gas G between the mounting surface 16a and the wafer W to cool the wafer W, which is adsorbed onto the mounting surface 16a, from the back side. This cools the wafer W, which has been heated by plasma or the like, and reduces the unevenness of the temperature distribution of the wafer W. For example, helium, an inert gas, can be used as the gas G.

[0027] The substrate 16 is mounted on the metal plate 24 via an adhesive layer 22. The metal plate 24 is made of a metallic material such as aluminum or titanium, and has internal channels 26 through which water H, a cooling substance, flows. This allows it to be used in vacuum processes where uniform temperature across the entire wafer surface is required, such as dry etching.

[0028] (Base material components) The substrate 16 according to this embodiment contains aluminum oxide as its main component. The substrate 16 also contains zirconium oxide, yttrium oxide, ytterbium oxide, magnesium oxide, calcium oxide, and silicon oxide as other additive components. The reason for using aluminum oxide (alumina: Al2O3) as the main component of the substrate 16 is explained below. In this embodiment, the wafer support 10 utilizes dielectric polarization to generate the adsorption force, and the dielectric portion functions as an electrostatic chuck. The adsorption force F is expressed by equation (1). F = (1 / 2) × ε0 × ε r 2 ×(V / d) 2 ...Equation (1) ε0: Permittivity of vacuum ε r : Relative permittivity of the dielectric layer V: Applied voltage d: Thickness of the dielectric layer

[0029] From equation (1), it is necessary to apply a high voltage to the dielectric in order to sufficiently adsorb the wafer W. In other words, the higher the applied voltage V, the greater the adsorption force F. Therefore, it is desirable that the substrate used for the wafer support 10 satisfies the following conditions (a) to (d). (a) High resistivity: High resistivity is required for the adsorption force (Coulomb force) to be expressed stably. (b) Plasma resistance: Resistant to corrosion by plasma. (c) High voltage resistance: The ability to withstand high voltages. (d) Heat resistance: Must be able to withstand the plasma heat generated during wafer etching.

[0030] Aluminum oxide satisfies the conditions (a) to (d) described above. In addition, the fact that it satisfies the following conditions (e) to (g) is one of the reasons why aluminum oxide is used as a dielectric layer. (e) High coefficient of thermal expansion: In this embodiment, the wafer support has a metal plate and a substrate (dielectric layer) bonded together, and aluminum oxide, which has a high coefficient of thermal expansion among ceramics, has a small difference in coefficient of thermal expansion from that of the metal plate. (f) High strength: The dielectric layer is designed to be thin in order to obtain sufficient adsorption force (in order to make d small in equation (1)), so it must have sufficient strength to not break even when thin. (g) High dielectric constant: The dielectric constant is relatively high at around 10 (in equation (1), ε r (The size increases), and a relatively strong adsorption force is obtained.

[0031] In recent years, the need for greater adsorption force has increased due to the application of high-pressure gas to the back surface of wafers to adsorb wafers with significant warping and to ensure temperature uniformity across the entire wafer surface. Therefore, to increase the adsorption force, it is necessary to thin the dielectric (decrease d) and increase the applied voltage (increase V), as shown in equation (1). However, conventional electrostatic chucks made of aluminum oxide present the following technical challenges. (i) Reduction in mechanical strength and breakage due to thinning of the sheet metal (ii) Insufficient dielectric strength of the dielectric due to increased applied voltage

[0032] (Improved dielectric breakdown voltage) Since dielectric breakdown occurs at pore locations, it is necessary to reduce the number of pores and achieve a dense firing process. Furthermore, reducing the particle size is necessary to improve the dielectric breakdown voltage. This is because, in order to make it difficult for current to flow, the grain boundaries through which carriers pass between electrodes should be long, which can be achieved by reducing the particle size. In addition, by reducing the particle size, the pores at the triple junction of the grain boundaries can be reduced, making dielectric breakdown at pore locations less likely.

[0033] (Improved strength) To achieve high strength, the material needs to be fired to a dense structure with minimal pores. Since strength decreases with grain growth, reducing the grain size is necessary to improve strength.

[0034] The inventors investigated additive components other than aluminum oxide, their content, and manufacturing methods, taking into consideration the properties (a) to (g) of aluminum oxide and the challenges (i) and (ii) arising from the increasing adsorption force required for electrostatic chucks in recent years.

[0035] (1) First, in order to improve dielectric strength and durability, zirconium oxide (ZrO2), which has a grain growth inhibiting effect on aluminum oxide, was selected as an additive. In addition, yttrium oxide (Y2O3) and ytterbium oxide (Yb2O3), which also have a grain growth inhibiting effect, were added. When aluminum oxide, yttrium oxide, and ytterbium oxide are added to aluminum oxide, the dielectric constant ε r This improves the adhesion force and increases the overall adhesion strength. Therefore, electrostatic chucks made primarily of aluminum oxide containing these additives can achieve similar adhesion strength even when the applied voltage is lower or the dielectric layer thickness is increased, compared to electrostatic chucks made of aluminum oxide without these additives. As a result, the dielectric strength and durability can be improved.

[0036] (2) Next, in order to further suppress grain growth in order to improve dielectric strength and strength, it is desirable to sinter at a low temperature. However, the aforementioned aluminum oxide, yttrium oxide, and ytterbium oxide have an effect of inhibiting the sintering of aluminum oxide, making densification difficult. Therefore, in order to enable low-temperature sintering of aluminum oxide, magnesium oxide (MgO), calcium oxide (CaO), and silicon oxide (SiO2) were added as sintering aids.

[0037] (3) Furthermore, in order to further suppress grain growth in order to improve dielectric strength and strength, it is necessary to lower the maximum temperature during firing. Therefore, in the manufacturing of the wafer support, firing was carried out by hot pressing.

[0038] The inventors have concluded that by employing the above methods (1) to (3), it is possible to realize a wafer support with a dielectric breakdown voltage of 100kV / mm or more, a bending strength of 600MPa or more, and a relative permittivity of 10.0 or more.

[0039] (Method of manufacturing wafer support) Figure 3 is a flowchart illustrating the method for manufacturing a wafer support according to this embodiment. First, a raw material powder is prepared by mixing a main raw material powder that will become a ceramic component, such as aluminum oxide, zirconium oxide, yttrium oxide, and ytterbium oxide, with a sintering aid powder such as magnesium oxide, calcium oxide, and silicon oxide, according to a predetermined blending amount (S10). The blending amount of aluminum oxide, which is the main component, is adjusted so that it is contained in the substrate at a concentration of 96% by mass or more. The aluminum oxide used in this embodiment is α-alumina with a purity of 99.99% or higher and an average particle size of about 0.4 μm.

[0040] To the main component, aluminum oxide, zirconium oxide, yttrium oxide, ytterbium oxide, magnesium oxide, calcium oxide, silicon oxide, etc., are added in predetermined proportions and mixed (S12). This mixing is carried out, for example, by wet mixing for 16 hours using a pot mill with a nylon pot and alumina balls. As a solvent, for example, ethanol with a concentration of about 0.75 kg / L (in the range of 0.1 to 1.0 kg / L) is used. Water or isopropyl alcohol (IPA) may be used instead of ethanol.

[0041] Next, the solvent is removed using an evaporator and the mixture is granulated. To further remove the solvent completely, the mixed raw materials are dried on a hot plate at 230°C (S14). Alternatively, the granulation may be performed using a spray dryer. The dried raw material powder is filled into a graphite mold and uniaxially pressed (S16). In this state, it is heated to 1400°C, held at a pressure of 30 MPa for 2 hours, and fired to produce a sintered body (S18).

[0042] Furthermore, a portion of the raw material powder or molded body may be replaced with a sintered body. In order to provide the electrodes of the electrostatic chuck inside the sintered body, when filling the hot press apparatus with raw material powder, molded body, or sintered body, a component or material that will become conductive after firing (e.g., metal plate, metal foil, conductive paste, coil, mesh, etc.) should be placed (embedded) in the predetermined position. The shape of the conductive material is not particularly limited. This firing can be carried out, for example, using a hot press apparatus. Hot pressing is performed in a non-oxidizing (inert) atmosphere, such as nitrogen or argon, but it may also be performed in pressurized nitrogen. The hot pressing temperature is, for example, in the range of 1350 to 1650°C. If the temperature is too low, sintering will be insufficient and densification will not occur, and if it is too high, grain growth will occur and the withstand voltage will decrease. The applied pressure is appropriate in the range of 20 to 50 MPa. The duration of hot pressing depends on the temperature and dimensions, but is usually about 1 to 4 hours. Subsequently, the sintered body is processed into the desired shape (S20), and the wafer support is manufactured.

[0043] Various properties of each sample produced by the above method (Examples 1 to 14 and Comparative Examples 1 to 16, described later) are measured and evaluated.

[0044] (Measurement of dielectric breakdown voltage) A DC voltage is applied to the sample in insulating oil, based on JIS C2110-1, 10.1 (short-time test). The voltage boosting rate is 1000 V / s. A plate-shaped sample with a thickness of 300 μm ± 50 μm is used for the measurement. The electrodes are as specified in JIS C2110-1, 5.2.1.3 (sphere-plate electrode), with the upper electrode being a φ20 mm sphere and the lower electrode being a φ25 mm plate. The dielectric breakdown voltage is defined as the applied voltage at which dielectric breakdown occurs divided by the thickness of the sample.

[0045] (Bending strength) Based on JIS R1601 3.1 (3-point bending strength), the measurement is performed with an external support distance of 30 mm and a sample size of 37 × 3 × 4 mm.

[0046] (Relative permittivity) The complex relative permittivity will be measured using the high-frequency IV method. The measurement frequency will be 50 MHz.

[0047] (Porosity) The porosity will be calculated based on JIS R 1655 (mercury intrusion method).

[0048] (Elemental analysis of impurities and metals) The content is quantified by ICP-AES (Inductively Coupled Plasma Emission Spectroscopy). The content of constituent elements in the ceramic sintered body in terms of oxides may also be calculated as follows: First, the constituent elements of the ceramic sintered body are qualitatively analyzed using an X-ray fluorescence analyzer (XRF) or an energy dispersive analyzer (EDS) attached to a scanning electron microscope (SEM). Next, each element detected by this qualitative analysis is quantitatively analyzed using an ICP emission spectrometer. Then, the content of each element measured by this quantitative analysis is converted to oxides. (particle size measurement) The fracture surface of the sample is photographed with a scanning electron microscope, and the particle size is calculated using the (linear) intercept method. A coefficient of 1.5 is used.

[0049] [Examples] Next, the characteristics of the wafer supports in each example and comparative example will be described. The content of ceramic components and sintering aid components in each example and comparative example is shown in Table 1. The samples in each example contain 96% by mass or more of aluminum oxide. The measurement results for each characteristic are also shown in Table 1. Note that the zirconium oxide raw material mixed when preparing each sample is not 100% pure zirconium oxide, but yttria-stabilized zirconia (3Y-PSZ), which is a mixture of 97 mol% (94.64 wt%) ZrO2 and 3 mol% (5.64 wt%) Y2O3. Therefore, even if yttrium oxide is not added to the raw material alone, trace amounts of yttrium oxide will be present as an additive in all samples. [Table 1]

[0050] Figure 4(a) is a graph showing the relationship between zirconium oxide content and dielectric breakdown voltage, Figure 4(b) is a graph showing the relationship between ytterbium oxide content and dielectric breakdown voltage, and Figure 4(c) is a graph showing the relationship between magnesium oxide content and dielectric breakdown voltage. Figure 5(a) is a graph showing the relationship between calcium oxide content and dielectric breakdown voltage, and Figure 5(b) is a graph showing the relationship between silicon oxide content and dielectric breakdown voltage.

[0051] The graph in Figure 4(a) plots the dielectric breakdown voltage values ​​for each sample, from lowest to highest zirconium oxide content: Comparative Example 16, Example 11, Example 1, Example 5, Comparative Example 15, Comparative Example 14, and Comparative Example 13. The results in Figure 4(a) show that samples with a zirconium content in the range of 0.47 to 1.83 mass% (in terms of zirconium oxide) satisfy the dielectric breakdown voltage requirement of 100 kV / mm or higher.

[0052] The graph in Figure 4(b) plots the dielectric breakdown voltage values ​​for each sample from Example 13, Example 11, Example 1, and Example 5, in descending order of ytterbium oxide content. From the results shown in Figure 4(b), samples with a ytterbium content in the range of 0 to 0.48 mass% (in terms of ytterbium oxide) satisfy the dielectric breakdown voltage requirement of 100 kV / mm or higher.

[0053] The graph in Figure 4(c) plots the dielectric breakdown voltage values ​​for each sample, from lowest to highest magnesium oxide content: Comparative Example 5, Comparative Example 4, Comparative Example 3, Example 7, Example 9, Example 1, Example 6, and Comparative Example 2. From the results shown in Figure 4(c), samples with a magnesium content in the range of 0.29 to 0.73 mass% in terms of magnesium oxide satisfy the dielectric breakdown voltage requirement of 100 kV / mm or higher.

[0054] The graph in Figure 5(a) plots the dielectric breakdown voltage values ​​for each sample—Comparative Example 8, Example 1, Example 4, and Comparative Example 6—from lowest to highest calcium oxide content. The results in Figure 5(a) show that samples with a calcium content in the range of 0.10 to 0.20 mass% (calcium oxide equivalent) satisfy the dielectric breakdown voltage requirement of 100 kV / mm or higher.

[0055] The graph in Figure 5(b) plots the dielectric breakdown voltage values ​​for each sample from Example 3, Example 1, Comparative Example 10, and Comparative Example 9, starting from the lowest silicon oxide content. From the results shown in Figure 5(b), samples with a silicon content in the range of 0 to 0.15 mass% in terms of silicon oxide satisfy the dielectric breakdown voltage requirement of 100 kV / mm or higher.

[0056] Thus, if a substrate contains 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium (calculated as zirconium oxide), and 0 to 0.48% by mass of yttrium or ytterbium (calculated as yttrium oxide or ytterbium oxide), the dielectric breakdown voltage will be 100kV / mm or higher, allowing for an increase in the voltage applied to the conductive material and improving the adsorption force.

[0057] Furthermore, as shown in each example, the substrate further contains at least one of the following: (1) magnesium in the form of magnesium oxide at 0.29 to 0.73% by mass, (2) calcium in the form of calcium oxide at 0.1 to 0.2% by mass, or (3) silicon in the form of silicon oxide at 0 to 0.15% by mass. This enables low-temperature sintering and allows for densification while suppressing the grain growth of aluminum oxide.

[0058] Furthermore, in each of the samples from Examples 1 to 5 and Examples 11 to 13, the porosity obtained by the mercury intrusion method is 1.0% or less. This results in a denser ceramic sintered body, which improves the dielectric breakdown voltage.

[0059] Furthermore, in the samples of each example, the average particle size D50 of the ceramic sintered body is 0.7 to 1.5 μm, preferably in the range of 0.8 to 1.3 μm. This enables the realization of a dense ceramic sintered body.

[0060] Furthermore, in each of the samples in Examples 1 to 8 and Examples 11 to 14, the bending strength of the ceramic sintered body is 600 MPa or higher. This makes deformation and fracture less likely to occur even when the dielectric layer is made thinner to improve the adsorption force.

[0061] Furthermore, in each of the samples in Examples 1 to 5 and Examples 11 to 13, the relative permittivity of the ceramic sintered body is 10.0 or higher. This improves the adsorption force.

[0062] The mass percentages of each additive shown in Table 1 represent the ideal content calculated from the amount of each additive used during mixing. On the other hand, when the additives in each sample prepared as a ceramic sintered body were analyzed by ICP-AES (inductively coupled plasma atomic emission spectroscopy), the content of all additives except aluminum oxide decreased. The rate of decrease in content varied depending on the sample and amount of additive used, but was at most about 20%. Therefore, the lower limit of the preferred content range for each additive (excluding aluminum oxide) contained in the substrate may be about 20% lower than the range mentioned above when analyzed by ICP-AES.

[0063] Next, an example of a method for manufacturing a wafer support according to this embodiment is shown. This manufacturing method includes the steps of: preparing a raw material powder containing 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium oxide, and 0 to 0.48% by mass of yttrium oxide or ytterbium oxide; arranging the raw material powder in a space of a predetermined shape; and firing the raw material powder by pressurizing the space in the range of 20 to 50 MPa and heating it in the range of 1350 to 1650°C. This makes it possible to manufacture a wafer support capable of achieving a desired adsorption force.

[0064] Although the present invention has been described above with reference to the embodiments and examples described above, the present invention is not limited to the embodiments described above, and the present invention also includes combinations and substitutions of the configurations of the embodiments as appropriate. Furthermore, it is possible to appropriately rearrange the combinations and order of processes in the embodiments or to make various design changes and other modifications to the embodiments based on the knowledge of those skilled in the art, and such modified embodiments may also be included in the scope of the present invention. [Explanation of Symbols]

[0065] 10 wafer support, 12 chamber, 14 upper electrode, 16 substrate, 16a mounting surface, 18 conductive member, 20 gas supply path, 22 adhesive layer, 24 metal plate, 26 flow path, 100 etching apparatus.

Claims

1. The device comprises a base material made of a ceramic sintered body and a conductive member in which at least a portion is embedded within the base material. The aforementioned substrate is It contains 96% or more by mass of aluminum oxide, It contains zirconium in the form of zirconium oxide in the form of 0.47 to 1.83% by mass. It contains yttrium or ytterbium in an amount of 0 to 0.48% by mass, calculated as yttrium oxide or ytterbium oxide. A wafer support characterized by the following features.

2. The aforementioned substrate further, (1) Magnesium in an amount equivalent to 0.29 to 0.73% by mass, or (2) Calcium in an amount of 0.1 to 0.2% by mass in terms of calcium oxide, (3) Silicon in terms of silicon oxide, 0 to 0.15% by mass, A wafer support according to claim 1, characterized by containing at least one of the following.

3. The wafer support according to claim 1 or 2, characterized in that the DC dielectric breakdown voltage of the ceramic sintered body is 100 kV / mm or more.

4. The wafer support according to claim 1 or 2, characterized in that the porosity of the ceramic sintered body obtained by the mercury intrusion method is 1.0% or less.

5. The wafer support according to claim 1 or 2, characterized in that the average particle size of the ceramic sintered body is 0.7 to 1.5 μm.

6. The wafer support according to claim 1 or 2, characterized in that the bending strength of the ceramic sintered body is 600 MPa or more.

7. The wafer support according to claim 1 or 2, characterized in that the relative permittivity of the ceramic sintered body is 10.0 or more.

8. The metal plate on which the aforementioned substrate is mounted further comprises The wafer support according to claim 1 or 2, characterized in that the metal plate has a channel formed therein through which a cooling substance flows.

9. The wafer support according to claim 1 or 2, further comprising a gas supply path for supplying gas between the substrate and the wafer mounted on the substrate.

10. A step of preparing a raw material powder containing 96% by mass or more of aluminum oxide, 0.47 to 1.83% by mass of zirconium oxide, and 0 to 0.48% by mass of yttrium oxide or ytterbium oxide, A step of placing the raw material powder in a space of a predetermined shape, A step of firing the raw material powder by pressurizing the space in the range of 20 to 50 MPa and heating it in the range of 1350 to 1650°C, A method for manufacturing a wafer support, characterized by including the following:

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