Sample holding tool

Abstract

A sample holding tool (10) of the present invention includes an aluminum nitride base (1) and an internal electrode (2) provided in the aluminum nitride base (1). The aluminum nitride base (1) includes a plurality of aluminum nitride particles (11) and aluminum oxynitride particles (12) at grain boundaries between the aluminum nitride particles (11). Titanium (13) is solid-solved in the aluminum oxynitride particles (12).

Description

[0001] This application is a divisional application of application number 202180047861.3, PCT application number PCT / JP2021 / 025470, application date: July 6, 2021, invention title: "Sample Holding Tool". Technical Field

[0002] This invention relates to sample holding tools. Background Technology

[0003] As known as prior art, aluminum nitride sintered bodies are shown in, for example, Japanese Patent Application Publication No. 6-128041, Japanese Patent Application Publication No. 11-335173 and Japanese Patent Application Publication No. 2020-88195. Summary of the Invention

[0004] The sample holding tool of the present invention comprises: an aluminum nitride matrix having a plurality of aluminum nitride particles and aluminum oxynitride particles located at grain boundaries between the aluminum nitride particles, wherein titanium is dissolved in the aluminum oxynitride particles. Attached Figure Description

[0005] Figure 1 This is a longitudinal cross-sectional view showing the sample holding tool of the present invention.

[0006] Figure 2 Is it displayed as follows Figure 1 The diagram shows aluminum nitride particles, aluminum oxynitride particles, and titanium dissolved in the aluminum oxynitride particles within the aluminum nitride matrix of the sample holding tool.

[0007] Figure 3 This is a schematic diagram showing aluminum nitride particles, aluminum oxynitride particles, and titanium dissolved in the aluminum oxynitride particles in an aluminum nitride matrix of another example sample holding tool.

[0008] Figure 4 This is a schematic diagram showing aluminum nitride particles, aluminum oxynitride particles, and titanium dissolved in the aluminum oxynitride particles in an aluminum nitride matrix of another example sample holding tool.

[0009] Figure 5 This is a schematic diagram showing aluminum nitride particles, aluminum oxynitride particles, and titanium dissolved in the aluminum oxynitride particles in an aluminum nitride matrix of another example sample holding tool.

[0010] Figure 6 This is a longitudinal section view showing another example of a specimen holding tool. Detailed Implementation

[0011] Hereinafter, an example of the sample holding tool 10 of the present invention will be described in detail with reference to the accompanying drawings.

[0012] like Figure 1 The sample holding tool 10 shown includes: an aluminum nitride substrate 1 containing aluminum nitride particles 11 and aluminum oxynitride particles 12, and an internal electrode 2 disposed in the aluminum nitride substrate 1. Furthermore, the so-called particles in this invention are referred to as grains having a continuous atomic arrangement.

[0013] The aluminum nitride substrate 1 is a component used to hold the sample. The aluminum nitride substrate 1 can be, for example, a plate-shaped component, or a circular or square plate-shaped component. When the aluminum nitride substrate 1 is plate-shaped, for example, one main surface can be a wafer mounting surface. The dimensions of the aluminum nitride substrate 1, for example, when the aluminum nitride substrate 1 is circular, can be 200–500 mm in diameter and 1–15 mm in thickness.

[0014] The aluminum nitride matrix 1 contains multiple aluminum nitride particles 11 and aluminum oxynitride particles 12. Here, aluminum nitride particles 11 are particles containing aluminum nitride, but may also contain impurities or lattice defects other than aluminum nitride. In addition, aluminum oxynitride particles 12 are particles containing aluminum oxynitride (AlON), but may also contain impurities or lattice defects other than aluminum oxynitride. In the aluminum nitride matrix 1, the proportion of aluminum nitride and aluminum oxynitride, for example, is analyzed by X-ray diffraction (XRD) using CuKα rays as the X-ray source. When comparing their intensities, aluminum nitride has a peak on the (100) plane near 2θ = 33.2°, and aluminum oxynitride, as an example, has a main peak on the (101) plane near 2θ = 33.8°, which is the main peak of 27R-aluminum oxynitride. The proportion of aluminum nitride particles 11 is about 95%, and aluminum oxynitride is about 5%.

[0015] The aluminum nitride substrate 1 has an internal electrode 2 on its surface or inside. When the sample holding tool 10 is used as an electrostatic chuck, the internal electrode 2 can be an electrostatic attraction electrode. In this case, the material of the internal electrode 2 can be a metal such as platinum or tungsten. Furthermore, the dimensions of the internal electrode 2 can, for example, have a thickness of 0.01 mm to 0.5 mm and an area of ​​30,000 mm². 2 ~190000mm 2 Alternatively, the internal electrode 2 can also be a heating resistor. In this case, the internal electrode 2 can contain a metallic component such as silver or palladium and a glass component containing oxides of materials such as silicon, bismuth, calcium, aluminum, and boron. The dimensions of the internal electrode 2 can be, for example, a thickness of 0.01 mm to 0.1 mm, a width of 0.5 mm to 5 mm, and a length of 1000 mm to 50000 mm. Furthermore, the aluminum nitride substrate 1 can have multiple internal electrodes 2. Additionally, the aluminum nitride substrate 1 can each have an electrostatic attraction electrode and a heating electrode 3.

[0016] The aluminum nitride matrix 1 of the present invention contains aluminum nitride particles 11 and aluminum oxynitride particles 12, wherein titanium 13 is dissolved in the aluminum oxynitride particles 12. In other words, the sample holding tool 10 of the present invention comprises: an aluminum nitride matrix 1 having a plurality of aluminum nitride particles 11 and aluminum oxynitride particles 12 located at grain boundaries between the aluminum nitride particles 11, and an internal electrode 2 disposed in the aluminum nitride matrix 1, wherein titanium 13 is dissolved in the aluminum oxynitride particles 12. Based on this, the volume resistivity of the aluminum nitride matrix 1 can be improved. The reasons are explained below.

[0017] First, the aluminum oxynitride particles 12 with titanium 13 dissolved in them have defects that are electrically positive compared to ordinary aluminum oxynitride particles 12. This is because the replacement of aluminum in the aluminum oxynitride particles 12 by titanium 13 results in one electron vacancy. Additionally, the aluminum nitride particles 11 have aluminum vacancies, which are electrically negative. Thus, the titanium defects in the aluminum oxynitride particles 12 and the aluminum vacancies in the aluminum nitride particles 11 have opposite charges. Therefore, the aluminum oxynitride particles 12 with titanium 13 dissolved in them can electrostatically pin the aluminum vacancies present near the grain boundaries within the aluminum nitride particles 11. As a result, the volume resistivity of the aluminum nitride matrix 1 can be increased compared to the case where titanium 13 is not dissolved in the aluminum oxynitride particles 12.

[0018] Figure 2 Examples illustrating the morphology of aluminum oxynitride particles 12 and aluminum nitride particles 11 in a matrix. Figure 2 In the diagram, the shaded area represents aluminum oxynitride particles 12, and the remaining area represents aluminum nitride particles 11. Additionally, the circular area within the aluminum oxynitride particles 12 represents titanium 13.

[0019] like Figure 2 As shown, the aluminum nitride matrix 1 of the present invention contains aluminum nitride particles 11 and aluminum oxynitride particles 12, wherein titanium 13 is dissolved in the aluminum oxynitride particles 12. The titanium 13 can be dissolved in multiple regions within the aluminum oxynitride particles 12. Alternatively, the aluminum nitride matrix 1 may contain aluminum oxynitride particles 12 without dissolved titanium 13. Furthermore, titanium 13 may be present at the grain boundaries between the aluminum nitride particles 11 and the aluminum oxynitride particles 12. Additionally, titanium 13 may also be present at the grain boundaries of the aluminum nitride particles 11. Furthermore, titanium 13 may also be present at the grain boundaries between the aluminum oxynitride particles 12.

[0020] In addition, such as Figure 3As shown, the aluminum oxynitride particles 12 can be elongated in shape. Alternatively, the regions where the aluminum oxynitride particles 12 exist within the aluminum nitride matrix 1 can be elongated. In this case, due to the presence of aluminum oxynitride particles 12 with dissolved titanium 13 over a wide range of grain boundaries, the aluminum oxynitride particles 12 with titanium 13 can electrostatically pin more aluminum vacancies present at the grain boundaries of the aluminum nitride particles 11. As a result, the volume resistivity of the aluminum nitride matrix 1 can be further improved.

[0021] Furthermore, if the aluminum nitride matrix 1 contains aluminum nitride particles 11 and aluminum oxynitride particles 12, and titanium 13 is dissolved in the aluminum oxynitride particles 12, the structure can be analyzed and confirmed using the following method. First, a specified portion of the aluminum nitride matrix 1 is removed using known methods such as cutting, slicing, or grinding. Next, the removed portion is thinned using known methods such as argon ion milling to obtain a sample. Then, the sample is analyzed using known methods such as transmission electron microscopy (TEM), electron diffraction, energy-dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), standardization analysis, or X-ray diffraction (XRD) to determine the aluminum oxynitride in the sintered body and the oxygen contained within it. Next, the titanium 13 in the sintered body is determined using the above methods or methods such as time-of-flight secondary ion mass spectrometry (TOF-SIMS). If the distributions of oxygen and titanium 13 overlap, titanium 13 can be dissolved in aluminum oxynitride particles 12.

[0022] Furthermore, aluminum oxynitride particles 12 can be located around the periphery of the internal electrode 2. Based on this, since the aluminum vacancies around the internal electrode 2 can be pinned, the movement of charge from the aluminum nitride to the internal electrode 2 when a voltage is applied can be suppressed. As a result, the volume resistivity of the aluminum nitride substrate 1 can be further improved. For example, the aluminum oxynitride particles 12 can be located at a position of 0.01 to 1.5 mm from the surface of the internal electrode 2.

[0023] Furthermore, the aluminum oxynitride particles 12 can be connected to the internal electrode 2. Based on this, charge moving from the aluminum nitride substrate 1 towards the electrode when a voltage is applied can be pinned, thereby achieving charge compensation. Based on this, the volume resistivity of the portion connected to the internal electrode 2 can be increased. As a result, the sample handling and removal capabilities can be further improved.

[0024] Furthermore, aluminum oxynitride particles 12 can be present in greater quantities on the side of the internal electrode 2 compared to the wafer mounting surface side of the sample holding tool 1. Based on this, the pinning effect on the side of the internal electrode 2 can be increased compared to the region on the wafer mounting surface side. Therefore, the response speed can be improved by rapidly increasing the movement of charge when power is supplied to the electrode. As a result, the polarization after the voltage is stopped applied to the electrostatic attraction electrode of the sample holding tool 1 is reduced, making sample loading and unloading easier.

[0025] Here, "wafer mounting surface side" refers to the region 0.01 to 1.5 mm from the wafer mounting surface. Similarly, "internal electrode 2 side" refers to the region 0.01 to 1.5 mm from the internal electrode 2. Since aluminum oxynitride particles 12 are more abundant on the internal electrode 2 side than on the wafer mounting surface side, the presence of oxygen on both the wafer mounting surface side and the internal electrode 2 side of the sample holding tool 1 can be confirmed by using, for example, wavelength dispersive X-ray spectroscopy (WDS) or X-ray photoelectron spectroscopy (XPS) as analytical instruments.

[0026] In addition, such as Figure 4 As shown, the aluminum oxynitride particles 12 may have sites where titanium segregates in the portion in contact with the aluminum nitride particles 11. Based on this, aluminum vacancies near the grain boundaries within the aluminum nitride particles 11 can be more effectively pinned electrostatically. Based on this, the volume resistivity of the aluminum nitride matrix 1 can be further improved.

[0027] In addition, such as Figure 5 As shown, the aluminum nitride particles 11 may have sites where titanium 13 segregates in the portion in contact with the aluminum nitride particles 12. Based on this, the titanium defects within the aluminum nitride particles 11 can electrostatically pin aluminum vacancies. Therefore, the volume resistivity of the aluminum nitride matrix 1 can be further improved.

[0028] Furthermore, the internal electrode 2 may contain aluminum nitride. Based on this, charge compensation can be adjusted between the aluminum nitride contained in the internal electrode 2 and the aluminum nitride particles 11 on the wafer holding side and the opposite side of the internal electrode 2. Therefore, charge shift can be reduced inside the sample holding tool 10.

[0029] In addition, such as Figure 6 As shown, the internal electrode 2 is an electrostatic attraction electrode, and the aluminum nitride substrate 1 also includes a heating electrode 3. Around the heating electrode 3, aluminum oxynitride particles 12 with titanium 13 dissolved in them can be present. Based on this, as the temperature increases, the pinning effect at areas where the charge generated by the aluminum nitride particles 11 increases can be improved. As a result, the volume resistivity of the aluminum nitride substrate 1 can be further improved. For example, the aluminum oxynitride particles 12 can be positioned at a distance of 0.01 to 1.5 mm from the surface of the heating electrode 3. Furthermore, the aluminum oxynitride particles 12 can also be connected to the heating electrode 3.

[0030] The following describes a method for preparing the aluminum nitride matrix 1 for the sample holding tool 10 of the present invention. First, aluminum nitride powder, alumina powder, titanium oxide powder, and a binder, which are substances capable of generating carbon during sintering, are mixed and shaped into a predetermined shape. Next, the shaped body is sintered at 2000°C or higher and cooled to 100°C. At this time, for example, supercooling can be performed by setting the cooling rate to 3.5–5.0°C per minute. At this time, 27R-aluminum oxynitride, which requires supercooling to form, precipitates in the sintered aluminum nitride body containing dissolved titanium 13. Based on this, an aluminum nitride matrix 1 containing aluminum oxynitride particles 12 with dissolved titanium 13 can be obtained. Using the above preparation method, a sample 1 containing aluminum oxynitride particles 12 with dissolved titanium 13 is prepared.

[0031] In addition, sample 2 containing undissolved titanium 13 aluminum oxynitride particles 12 was prepared by a conventional preparation method without supercooling. Their volume resistivity was evaluated using the following method. First, samples with a height of 50–60 mm, a width of 50–60 mm, and a thickness of 0.5–2 mm were cut from the aluminum nitride sintered body, acid-alkali washed, and dried. Next, a main electrode, a ring electrode, and a counter electrode were printed on the sample, and it was baked. The volume resistivity was measured using the three-terminal method (JIS C 2141:1992). The results are shown in Table 1.

[0032] Table 1

[0033]

[0034] As shown in Table 1, sample 2, which does not contain aluminum oxynitride particles 12 with dissolved titanium 13, has a volume resistivity of 5 × 10⁻⁶ at 400 °C. 8 Ωcm. In contrast, sample 1, containing aluminum oxynitride particles 12 with titanium 13 in solid solution, has a volume resistivity of 5 × 10⁻⁶ at 400 °C. 9 Ωcm. Thus, by including aluminum oxynitride particles 12 containing titanium 13 in solid solution, the volume resistivity of the aluminum nitride substrate 1 used for the sample holding tool 10 can be improved. By using an aluminum nitride substrate 1 like this as the sample holding tool 10, polarization after the voltage application to the electrostatic attraction electrode stops can be eliminated, and wafer loading and unloading can be performed easily.

[0035] Explanation of reference numerals in the attached figures

[0036] 1: Aluminum nitride matrix

[0037] 11: Aluminum nitride particles

[0038] 12: Aluminum oxynitride particles

[0039] 13: Titanium

[0040] 2: Internal electrodes

[0041] 3: Heating electrode

[0042] 10: Sample holding tool

Claims

1. A sample holding tool, characterized in that, The device comprises an aluminum nitride matrix having a plurality of aluminum nitride particles and aluminum oxynitride particles located at grain boundaries between the aluminum nitride particles. The aluminum oxynitride particles contain titanium dissolved in solid solution.

2. The sample holding tool as described in claim 1, wherein, The aluminum oxynitride particles are elongated in shape.

3. The sample holding tool as described in claim 2, wherein, The aluminum oxynitride particles are continuously connected to a plurality of aluminum nitride particles.

4. The sample holding tool according to any one of claims 1 to 3, wherein, The titanium is dissolved in multiple regions within the aluminum oxynitride particles.

5. The sample holding tool according to any one of claims 1 to 3, wherein, The aluminum nitride matrix has aluminum oxynitride particles that do not have the titanium dissolved in them.

6. The sample holding tool according to any one of claims 1 to 3, wherein, The titanium is present at the grain boundaries between the aluminum nitride particles and the aluminum oxynitride particles.

7. The sample holding tool according to any one of claims 1 to 3, wherein, The titanium is present at the grain boundaries of the aluminum oxynitride particles.

8. The sample holding tool according to any one of claims 1 to 3, wherein, The titanium is present at the grain boundaries between the aluminum oxynitride particles.

9. The sample holding tool according to any one of claims 1 to 3, wherein, The aluminum oxynitride particles have regions where titanium segregates in the portion in contact with the aluminum nitride particles.

10. The sample holding tool according to any one of claims 1 to 3, wherein, The aluminum nitride particles have regions where titanium segregates in the portion in contact with the aluminum oxynitride particles.

11. The sample holding tool as claimed in claim 2 or claim 3, wherein, Electrodes are provided inside the aluminum nitride matrix.

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