KR100381589B1 - Aluminum nitride sintered bodies and semiconductor-producing members including same - Google Patents

Abstract

An object of the present invention is to reduce volume resistivity and to suppress so-called varistor behavior between applied voltage and leakage current in a high purity aluminum nitride sintered body.

The aluminum nitride sintered body contains aluminum nitride as a main component, has a polycrystalline structure of aluminum nitride crystals, and contains 0.01 wt% to 1.0 wt% of cerium in terms of oxide. Preferably, the volume resistivity at room temperature is 1 × 10 ⁸ Ω · cm to 1 × 10 ¹² Ω · cm when the applied voltage is 500 V / mm, and the content of metal impurities excluding cerium is 100 ppm or less, and carbon The content of is 0.05% by weight or less.

Description

Aluminum nitride sintered body and member for semiconductor manufacturing {ALUMINUM NITRIDE SINTERED BODIES AND SEMICONDUCTOR-PRODUCING MEMBERS INCLUDING SAME}

The present invention relates to an aluminum nitride sintered body and a corrosion resistant member using the same.

As a method of absorbing and holding a semiconductor wafer, an electrostatic chuck using a Johnson-Rahbek force is useful. When the volume resistivity of the substrate of the electrostatic chuck is 10 ⁸ to 10 ¹² Ω · cm, high adsorption force and high responsiveness can be obtained. Therefore, in the development of the electrostatic chuck, it is important to control the volume resistivity of the substrate to 10 ⁸ to 10 ¹² Ω · cm in the use temperature range.

For example, in Japanese Patent Application Laid-Open No. 9-315867, the applicant has shown that by adding a small amount of yttrium oxide to high-purity aluminum nitride, the volume resistivity can be controlled to 10 ⁸ to 10 ¹² Ω · cm at room temperature.

In the aluminum nitride sintered body as described in Japanese Patent Application Laid-Open No. 9-315867, although the resistance value can be reduced, the so-called varistor behavior exhibits a large change in the leakage current when the applied voltage changes. I could see that. That is, when the leakage current when the voltage of V is applied to the aluminum nitride sintered body is I, and the relation between V and I is I = kV ^α (k is a constant and α is a nonlinear coefficient), the value of α It turned out that this is a high value of 1.5-2.0. The voltage-current behavior that does not obey this Ohm's law is undesirable for a member for a semiconductor manufacturing apparatus, especially for a semiconductor susceptor incorporating an electrostatic chuck electrode. For example, in the case of a ceramic electrostatic chuck, there is a dielectric layer between the electrostatic chuck electrode and its surface, but there is some variation or deviation in the thickness of the dielectric layer. Since the voltage between the electrostatic chuck electrode and its surface is constant, the applied voltage (V / mm) becomes small in the region where the dielectric layer is thick, and the applied voltage becomes large in the region where the dielectric layer is thin. If the leakage current changes in a manner that does not obey Ohm's law with respect to the change in the applied voltage, the adsorption force may become unstable because the variation in the surface of the leakage current becomes large.

An object of the present invention is to reduce volume resistivity and suppress varistor behavior between applied voltage and leakage current in a high purity aluminum nitride sintered body.

BRIEF DESCRIPTION OF THE DRAWINGS The graph which shows the relationship between the applied voltage V and the leakage current I in the sintered compact of each Example.

The present invention relates to an aluminum nitride sintered body comprising aluminum nitride as a main component, having a polycrystalline structure of aluminum nitride crystals, and containing 0.01 wt% to 1.0 wt% of cerium as an oxide.

The inventor of the present invention can reduce the volume resistivity of the sintered body by containing a small amount of cerium in the aluminum nitride sintered body, and can suppress the varistor behavior between the applied voltage and the leakage current, and in some cases, almost Ohm's law. It has been found that the following behavior can be obtained to reach the present invention.

The content of aluminum in the sintered compact of the present invention should be such that the amount of aluminum nitride particles can be present in the main phase, preferably 35% by weight or more, and more preferably 50% by weight or more.

In the polycrystalline structure of the aluminum nitride crystal, a small amount of other crystal phase may be included in addition to the aluminum nitride crystal.

In order to achieve the effect of the present invention, the content of cerium must be 0.01% by weight or more in terms of oxide. The cerium content is more preferably 0.1% by weight or more in terms of oxide.

In addition, since the volume resistivity of the aluminum nitride sintered compact tends to increase when the content of cerium exceeds 1.0 wt%, the content of cerium should be 1.0 wt% or less in order to lower the volume resistivity. And it is more preferable to make content of cerium into 0.7 weight% or less in conversion of oxide.

Japanese Laid-Open Patent Publication No. 11-100271 describes aluminum nitride ceramics having a low volume resistivity containing cerium in an amount of 2 to 20 mol% in terms of oxide and containing CeAlO ₃ . When this cerium content is converted into weight%, it will be about 7.9 to 51 weight%. This is to add a large amount of cerium to aluminum nitride ceramics to precipitate a large amount of CeAlO ₃ (cerium aluminate) at the grain boundaries of the aluminum nitride particles, to generate a continuous phase of cerium aluminate at the grain boundaries so that electricity flows in the continuous phase. .

When the aluminum nitride sintered compact of this invention is measured by X-ray diffraction method, it may consist of an aluminum nitride single phase, and an aluminum nitride phase and a cerium aluminate phase. In general, when the content of cerium in the sintered body increases, the cerium aluminate phase tends to be produced.

In particular, when measured by high power XRD, one or both of the aluminum nitride phase, the cerium aluminate phase, and the CeAl ₁₁ O ₁₈ phase may be detected. Measurement conditions in the high power XRD will be described later.

Preferably, the content of metal impurities other than cerium is 100 ppm or less, particularly preferably 50 ppm or less. Thereby, the high corrosion resistance sintered compact suitable for the use in the case where there should be few impurities, such as a semiconductor related use, can be provided.

Moreover, in preferable embodiment of this invention, content of the rare earth element except cerium in the aluminum nitride sintered compact is 0.01 weight%-0.5 weight% in conversion to oxide.

The inventors of the present invention have found that in the aluminum nitride sintered body of the present invention in which trace amounts of cerium are added, reddish brown to dark brown spots occur in some sintered bodies. However, no change in various properties corresponding to such spots was observed at all.

The inventor of the present invention adds a rare earth element other than cerium in combination with cerium, and contains 0.01% by weight or more of the rare earth element in terms of oxide, thereby preventing or suppressing staining with little change in various properties. I found that.

From the viewpoint of preventing staining of the sintered compact, the content of the rare earth elements other than cerium is more preferably 0.03% by weight or more in terms of oxide.

In addition, from the viewpoint of providing a high corrosion resistant sintered body suitable for use in the case where there should be almost no impurities such as semiconductor-related applications, and the viewpoint of obtaining a low volume resistivity, the content of the rare earth element is 0.5% by weight or less in terms of oxide. desirable.

In addition, from the viewpoint of providing a high corrosion-resistant sintered body suitable for use in the case where there should be almost no impurities such as semiconductor related applications, the content of metal elements other than aluminum and rare earth elements (including cerium) is 100 ppm or less. It is preferable to set it as 50 ppm or less, and it is more preferable.

Although the said rare earth element is not specifically limited, Yttrium, neodymium, samarium, gadolinium, dysprosium, erbium, ytterbium is preferable, and yttrium is especially preferable.

It is preferable that content of carbon of the aluminum nitride sintered compact of this invention is 0.05 weight% or less.

Moreover, it is preferable that the average particle diameter of the aluminum nitride crystal which comprises an aluminum nitride sintered compact is 5 micrometers-20 micrometers.

It is preferable that the relative density of an aluminum nitride sintered compact is 95% or more.

In the aluminum nitride sintered body of the present invention, the varistor behavior is suppressed in the relationship between the applied voltage and the leakage current. Specifically, when the leakage current when the voltage of V is applied is I, and the relation between V and I is I = kV ^α (k is a constant and α is a nonlinear coefficient), V is 100 V / The value of alpha can be made 1.0 or more and 1.5 or less as it is the range of mm-1000 V / mm.

The reason for obtaining such remarkable actions and effects is not clear, but it can be inferred as follows.

In the case of sintering high-purity aluminum nitride powder, it is considered that the barrier at the grain boundary is high and the electrical conduction at the grain boundary is effectively tunneled, and thus electrical conduction characteristics are not followed according to Ohm's law.

In addition, when a small amount of yttrium oxide is added to the high purity aluminum nitride powder and sintered, for example, oxygen is dissolved in the aluminum nitride particles in the sintered compact, and the electrical resistance in the particles is reduced. However, it is believed that the barrier at the grain boundary is high, and the electrical conduction at the grain boundary is effected effectively in the tunnel, and as a result, it exhibits electrical conduction characteristics not following Ohm's law.

In contrast, when a small amount of cerium oxide is added to a high purity aluminum nitride powder and sintered, impurity oxygen (present in the form of alumina) contained in the aluminum nitride raw material powder reacts with cerium oxide to generate a cerium aluminate phase. And the liquid phase sintering of aluminum nitride is promoted.

As a result of promoting the liquid phase sintering, the aluminum nitride particles are coarsened. Also in the final sintered compact, cerium-aluminum oxide was confirmed to remain as a precipitate at the grain boundaries. In addition, it is considered that part of the oxygen contained in the raw material powder is dissolved in the aluminum nitride particles in accordance with the liquid phase sintering, and a donor level of oxygen is formed in the aluminum nitride particles, thereby reducing the intraparticle resistance of the particles. In this way, it is thought that the coarsening of the aluminum nitride particles reduces the number of grain boundaries with high resistance and the particle resistance of the particles decreases, thereby reducing the volume resistivity of the sintered body as bulk.

At the same time, the barrier at the grain boundary is lowered by the addition of cerium oxide, and as a result, it is considered that the aluminum nitride particles are in ohmic contact with each other. However, there is much uncertainty about the control of the resistance value at such a grain boundary.

The raw material of aluminum nitride can use the thing by various manufacturing methods, such as the direct nitriding method, the reduction nitriding method, and the gas phase synthesis method from alkyl aluminum.

To the raw material powder of aluminum nitride, a compound (cerium oxide precursor) which produces cerium oxide by heating, such as cerium nitrate, cerium sulfate, cerium oxalate, or the like can be added. The cerium oxide precursor may be added in a powder state. Furthermore, after dissolving a compound such as cerium nitrate or cerium sulfate in a solvent to obtain a solution, the solution can be added to the raw material powder. As described above, when the cerium oxide precursor is dissolved in a solvent, cerium can be highly dispersed between the aluminum nitride particles. This is particularly useful when the amount of cerium added is small.

The shaping | molding of a sintered compact can apply well-known methods, such as a dry press method, a doctor blade method, an extrusion method, and an injection method.

The sintered compact of the present invention is preferably hot press sintering, and the sintered compact is preferably hot press sintered at a pressure of 50 kgf / cm ² or higher.

The sintered compact of this invention can be used suitably as various members in a semiconductor manufacturing apparatus, such as a processing apparatus of a silicon wafer, and a liquid crystal display manufacturing apparatus.

Especially the sintered compact of this invention is suitable for corrosion-resistant members, such as a susceptor for semiconductor manufacturing apparatuses. Moreover, it is suitable also about the metal embedding goods which embed | buried the metal member in this corrosion resistant member. As a corrosion resistant member, the susceptor, a ring, a dome, etc. which are provided in a semiconductor manufacturing apparatus can be illustrated, for example. In the susceptor, a resistive heating element, an electrostatic chuck electrode, an electrode for high frequency generation, and the like can be embedded.

In addition, the sintered body of the present invention is particularly useful for the substrate of the electrostatic chuck because the resistance value is low, high purity, and the applied voltage-leakage current relationship is close to the behavior that follows the Ohm's law. In addition to the electrostatic chuck electrode, a resistive heating element, a plasma generating electrode, and the like can be further embedded in the substrate of the electrostatic chuck.

Below, the aluminum nitride sintered compact was actually manufactured and the characteristic was evaluated.

Sintered bodies of Examples and Comparative Examples shown in Tables 2 to 6 were produced using commercially available reduced nitriding powders and commercially available cerium nitrate. The composition of this powder is shown in Table 1.

Si 4 ppm Fe 3 ppm Ti Less than 1 ppm Ca 7 ppm Mg 5 ppm K Less than 0.5 ppm Na 1 ppm P Less than 1 ppm Cr 1 ppm Mn Less than 0.1 ppm Ni Less than 1 ppm Cu Less than 1 ppm Zn Less than 0.1 ppm Y Less than 0.5 ppm W 1 ppm B Less than 1 ppm N 33.87 wt% O 0.93 wt% C 0.03 wt%

100 parts by weight of aluminum nitride powder and cerium nitrate at each weight (in parts by weight, expressed in parts by weight, expressed in oxide units) shown in Tables 2 to 6 were weighed and introduced into isopropyl alcohol, and a nylon pot and a stone were Wet mixing was carried out using (玉石) for 4 hours. After mixing, the slurry was extracted and dried at 110 ° C. The dried powder was heat-treated at 450 ° C. for 5 hours in an air atmosphere, whereby the nylon component mixed at the time of wet mixing was lost to obtain a raw material powder for sintering. Cerium nitrate was dissolved in isopropyl alcohol.

This raw powder was uniaxially press-molded at a pressure of 200 kgf / cm ² to prepare a disk shaped body having a diameter of 100 mm and a thickness of 20 mm. This molded body was accommodated in a graphite mold. The molded body was sintered by the hot press method. The press pressure was 200 kgf / mm ² , and the sintering temperature was 1900 ° C. or 2000 ° C., maintained at 1900 ° C. or 2000 ° C. for 4 hours, and cooled. Vacuum was set between room temperature and 1000 ° C, and nitrogen gas was introduced at a pressure of 1.5 kgf / cm ² between 1000 ° C and 1900 ° C or 2000 ° C.

The following evaluation was performed about the obtained sintered compact, and the evaluation result was shown to Tables 2-6.

(Density) It measured by the Archimedes method which used pure water as a medium.

(Content of Impurity Metal) It was quantified by inductively coupled plasma emission spectrum.

(Oxygen amount) It quantified by the inert gas fusion infrared absorption method.

(Carbon amount) Quantification was performed by a high frequency heating infrared absorption method.

(CeO ₂ content) The amount of cerium was quantified by the inductively coupled plasma emission spectrum, and the content of CeO ₂ was calculated from this quantitative value.

(Crystalline phase) It confirmed by XRD. As measurement conditions, 35 kV, 20 mA, and 2θ were set to 20 to 70 ° using CuKα.

(Crystal phase: high power XRD) It confirmed by high power XRD. As measurement conditions, 50 kV, 300 mA, and 2θ were set to 20 to 70 ° using CuKα.

(Room temperature volume resistivity) It measured by the volume resistivity measuring method of the insulator based on JIS2141 in vacuum. However, the dimensions of the test piece were 50 mm x 50 mm x 1 mm, the diameter of the main electrode was 20 mm, the inner diameter of the guard electrode was 30 mm, the outer diameter of the guard electrode was 40 mm, and the diameter of the applied electrode was 45 mm was used as the material of the electrode. The applied voltage was varied in the range of 50 V / mm to 1000 V / mm. After the voltage was applied, the volume resistivity was calculated by reading the current value one minute later. In addition, in the "room temperature volume resistivity" column of Table 2-Table 5, the volume resistivity at 500 V / mm of applied voltage was described. And the title of "9E + 11" in the table means the "9 × 10 ^11", and other case as defined.

(Thermal conductivity) It measured by the laser flash method.

(Strength) It measured by the room temperature 4-point bending strength test method based on JISR1601.

(AlN particle diameter) The microstructure of the sintered compact was observed with the electron microscope, the particle diameter of 30 particle | grains was measured, and the average value was described.

(α) The leakage current value was measured while varying the applied voltage to 100 to 1000 V / mm, and plotted as shown in FIG. 1. 1, the graphs of Examples 1 and 10 and Comparative Examples 1 and 6 are shown. In Fig. 1, the vertical axis I denotes a leakage current and is indicated in logarithm. In addition, the horizontal axis V represents an applied voltage and is indicated in logarithm. The plot of each example was approximated to a straight line by the least square method to calculate the slope of this straight line, and this slope was shown in the table as α.

(Stain) In the following cases, it was judged that there was a stain.

(1) When the color classification and / or brightness classification differ in the sign of "Standard Color Sample Book for Paints" issued by the Japan Industrial Association.

(2) In case of the sign of "Standard Color Sample Book for Paints" issued by the Japan Industrial Association, the color classification and the brightness classification are the same, and the saturation classification is different by two or more levels.

Example 1 Example 2 Example 3 Example 4 Example 5 Raw material combination composition weight part AlN 100 100 100 100 100 CeO ₂ 0.06 0.15 0.3 0.5 0.6 Sintering Temperature (。C) 1900 1900 1900 1900 1900 Density (g / cm ³ ) 3.26 3.27 3.26 3.27 3.27 Impurity Metal Content (ppm) Less than 30 Less than 30 Less than 30 Less than 30 Less than 50 Oxygen amount (% by weight) 0.81 0.82 0.83 0.83 0.85 Carbon amount (% by weight) 0.03 0.04 0.04 0.04 0.03 CeO ₂ content (% by weight) 0.05 0.15 0.28 0.45 0.52 Crystal phase (XRD) AlN AlN AlN CeAlO ₃ AlN CeAlO ₃ AlN CeAlO ₃ Crystal Phase (High Power XRD) AlN CeAl ₁₁ O ₁₈ AlN CeAl ₁₁ O ₁₈ AlN CeAlO ₃ CeAl ₁₁ O ₁₈ AlN CeAlO ₃ CeAl ₁₁ O ₁₈ AlN CeAlO ₃ CeAl ₁₁ O ₁₈ Room temperature volume resistivity (Ωcm) 9E + 11 2E + 10 2E + 10 7E + 10 1E + 11 Thermal Conductivity (W / mK) 98 95 95 100 108 Strength (MPa) 370 340 350 310 310 AlN particle size (㎛) 5.4 5.9 6.1 6.3 6.5 α One One One One One stain none none none none none

Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 7 Raw material combination composition weight part AlN 100 100 100 100 100 CeO ₂ 0.8 0 1.5 4.6 0.03 Sintering temperature (。C) 1900 1900 1900 1900 2000 Density (g / cm ³ ) 3.28 3.26 3.28 3.35 3.27 Impurity Metal Content (ppm) Less than 50 Less than 30 Less than 50 Less than 50 Less than 30 Oxygen amount (% by weight) 0.94 0.81 1.15 1.82 0.61 Carbon amount (% by weight) 0.04 0.03 0.04 0.05 0.03 CeO ₂ content (% by weight) 0.74 Less than 0.0001 1.41 3.93 0.01 Crystal phase (XRD) AlN + CeAlO ₃ AlN AlN CeAlO ₃ AlN CeAlO ₃ AlN Crystal Phase (High Power XRD) AlN CeAlO ₃ CeAl11018 AlN AlN CeAlO ₃ AlN CeAlO ₃ AlN + CeAl11018 Room temperature volume resistivity (Ωcm) 5E + 11 2E + 14 2E + 13 1E + 15 1E + 09 Thermal Conductivity (W / mK) 110 92 115 120 90 Strength (MPa) 330 370 390 420 290 AlN particle size (㎛) 6.6 3.5 6.4 6.5 7.2 α One 2 One One 1.5 stain has exist has exist has exist none none

Example 8 Example 9 Example 10 Example 11 Example 12 Raw material combination composition weight part AlN 100 100 100 100 100 CeO ₂ 0.06 0.15 0.3 0.5 0.6 Sintering temperature (。C) 2000 2000 2000 2000 2000 Density (g / cm ³ ) 3.27 3.27 3.27 3.26 3.27 Impurity Metal Content (ppm) Less than 30 Less than 30 Less than 30 Less than 30 Less than 30 Oxygen amount (% by weight) 0.62 0.61 0.60 0.58 0.60 Carbon amount (% by weight) 0.03 0.04 0.04 0.04 0.04 CeO ₂ content (% by weight) 0.02 0.05 0.11 0.15 0.21 Crystal phase (XRD) AlN AlN AlN AlN CeAlO ₃ AlN CeAlO ₃ Crystal Phase (High Power XRD) AlN CeAl ₁₁ O ₁₈ AlN CeAlO ₃ CeAl ₁₁ O ₁₈ AlN CeAlO ₃ CeAl ₁₁ O ₁₈ AlN CeAlO ₃ AlN CeAlO ₃ Room temperature volume resistivity (Ωcm) 2E + 9 3E + 9 6E + 9 1E + 10 7E + 9 Thermal Conductivity (W / mK) 90 90 92 96 96 Strength (MPa) 300 300 310 320 310 AlN particle size (㎛) 7.6 7.6 7.5 7.7 7.6 α 1.5 1.5 1.5 One One stain none has exist has exist has exist has exist

Example 13 Example 14 Example 15 Comparative Example 4 Comparative Example 5 Comparative Example 6 Raw material combination composition weight part AlN 100 100 100 100 100 100 CeO ₂ 0.8 1.5 4.6 0.0 7.6 - Y ₂ O ₃ - - - - - 0.3 Sintering temperature (。C) 2000 2000 2000 2000 2000 1900 Density (g / cm ³ ) 3.27 3.27 3.34 3.26 3.41 3.27 Impurity Metal Content (ppm) Less than 30 Less than 50 Less than 50 Less than 30 Less than 50 Less than 30 Oxygen amount (% by weight) 0.59 0.65 0.82 0.79 1.03 0.84 Carbon amount (% by weight) 0.04 0.04 0.04 0.03 0.05 0.03 CeO ₂ content (% by weight) 0.27 0.55 0.98 Less than 0.0001 2.05 Less than 0.0001 Crystal phase (XRD) AlN + CeAlO ₃ AlN + CeAlO ₃ AlN + CeAlO ₃ AlN AlN CeAlO ₃ AlN Crystal Phase (High Power XRD) AlN CeAlO ₃ AlN CeAlO ₃ AlN CeAlO ₃ Room volume resistivity (Ωcm) 2E +10 7E +10 2E +11 8E +12 5E +13 8E +10 Thermal Conductivity (W / mK) 100 108 115 86 148 92 Strength (MPa) 320 330 350 340 360 330 AlN particle size (㎛) 7.7 7.8 8.2 5.2 8.5 6.6 α One One One 2 One 2 stain has exist has exist has exist has exist none none

Example 16 Example 17 Example 18 Example 19 Raw material combination composition weight part AlN 100 100 100 100 CeO ₂ 0.08 0.15 0.15 0.08 Y ₂ O ₃ 0.1 0.1 0.1 0.05 Sintering Temperature (。C) 2000 2000 1900 2000 Density (g / cm ³ ) 3.26 3.26 3.27 3.26 Impurity Metal Content (ppm) Less than 30 Less than 30 Less than 30 Less than 30 Oxygen amount (% by weight) 0.62 0.63 0.85 0.62 Carbon amount (% by weight) 0.04 0.04 0.04 0.04 CeO ₂ content (% by weight) 0.03 0.05 0.13 0.03 Y ₂ O ₃ content (% by weight) 0.06 0.04 0.09 0.03 Crystal Phase (High Power XRD) AlN CeAlO ₃ AlN CeAlO ₃ AlN CeAlO ₃ CeAl11018 Y ₃ Al5012 AlN CeAlO ₃ CeAl11018 Room volume resistivity (Ωcm) 3E + 10 8E + 11 9E + 11 6E + 10 Thermal Conductivity (W / mK) 90 93 95 90 Strength (MPa) 300 340 360 360 AlN particle size (㎛) 7.7 7.5 6.1 7.7 α 1.5 One One 2 stain none none none none

In Examples 1 to 6, the content of CeO ₂ in the sintered compact is 0.05 to 0.74% by weight, showing a tendency to decrease slightly compared with the time of raw material combination. The amount of oxygen is 0.80 to 0.94% by weight, which is relatively large. In the sintered compact, when the content of CeO ₂ is 0.20 wt% or less, the sintered compact is almost aluminum nitride single phase, but when the content of CeO ₂ exceeds 0.20 wt%, cerium aluminate phase precipitates. The room temperature volume resistivity of the sintered compact of each Example is comparatively low, and (alpha) is also low.

In the Comparative Example 1, but the content of CeO ₂ is less than 0.0001% by weight, a high volume resistivity, even larger α. Comparative Example 2, in 3, the content of CeO ₂ exceeds 1 wt%, but the higher the volume resistivity.

In the Examples 7 to Example 15, the content of CeO ₂ in the sintered body is 0.01~0.98 weight%. The amount of oxygen is 0.58 to 0.82 wt%, which is relatively large. The room temperature volume resistivity of the sintered compact of each Example is comparatively low, and (alpha) is also low.

In Comparative Example 4, the content of CeO _{2 in} the sintered compact was less than 0.0001% by weight, the volume resistivity was high, and α was also large. In Comparative Example 5, a high content of CeO ₂ of the sintered body, there is a high volume resistivity. In Comparative Example 6, the volume resistivity of the sintered compact is lowered by adding 0.3 parts by weight of yttrium oxide powder instead of adding cerium oxide powder to the raw material powder. 0.28 wt% of yttrium oxide was contained in the sintered compact, but the content of cerium oxide was less than 0.0001 wt%. As a result, the volume resistivity at room temperature was significantly reduced, but α became 2.

In addition, when measured by high power XRD, CeAl ₁₁ O ₁₈ phase is detected together with AlN phase in Examples 1, 2, 7, and 8, and CeAlO ₃ phase is detected together with AlN phase in Examples 11 to 15. In Examples 3, 4, 5, 6, 9 and 10, CeAl ₁₁ O ₁₈ phase and CeAlO ₃ phase were detected together with the AlN phase.

Further, in Examples 16 to 19, yttrium oxide was added together with cerium oxide, but there were no significant changes in characteristics such as crystal phase, volume resistivity, thermal conductivity, strength, α, and the like. In Examples 16 to 19, reddish brown to dark brown stains did not appear.

As described above, according to the present invention, it is possible to reduce the volume resistivity in the high-purity aluminum nitride sintered body and to suppress the varistor behavior between the applied voltage and the leakage current.

Claims (24)

Its main component is aluminum nitride, it has a polycrystalline structure of aluminum nitride crystals, contains cerium in an amount of 0.01 to 1.0 wt% in terms of oxide, and has a volume resistivity of 1 at room temperature when the applied voltage is 500 V / mm. × 10 ⁸ Ω · cm to 1 × 10 ¹² Ω · cm, leakage current when applying a voltage of V is I, and the relation between V and I is I = kV ^α (k is a constant, α is nonlinear Coefficient), the value of α is 1.0 to 1.5 when V is in the range of 100 V / mm to 1000 V / mm. delete The aluminum nitride sintered body according to claim 1, wherein the content of metal elements other than aluminum and cerium is 100 ppm or less. The aluminum nitride sintered body according to claim 1, wherein the content of the rare earth elements other than cerium is 0.01 wt% to 0.5 wt% in terms of oxides. The aluminum nitride sintered body according to claim 4, wherein the content of the metal elements excluding aluminum and rare earth elements is 100 ppm or less. The aluminum nitride sintered body according to claim 4, wherein the rare earth element is yttrium. The aluminum nitride sintered body according to claim 1, wherein the content of carbon is 0.05% by weight or less. The aluminum nitride sintered body according to claim 3, wherein the content of carbon is 0.05% by weight or less. The aluminum nitride sintered body according to claim 4, wherein the content of carbon is 0.05% by weight or less. The aluminum nitride sintered compact according to claim 1, wherein an average particle diameter of the aluminum nitride crystals constituting the aluminum nitride sintered compact is 5 µm to 20 µm. The aluminum nitride sintered body according to claim 3, wherein the average particle diameter of the aluminum nitride crystals constituting the aluminum nitride sintered body is 5 µm to 20 µm. The aluminum nitride sintered compact according to claim 4, wherein an average particle diameter of the aluminum nitride crystals constituting the aluminum nitride sintered compact is 5 µm to 20 µm. delete delete delete The aluminum nitride sintered body according to claim 1, which is an aluminum nitride single phase as measured by an X-ray diffraction method. The aluminum nitride sintered body according to claim 3, which is an aluminum nitride single phase as measured by an X-ray diffraction method. The aluminum nitride sintered body according to claim 4, which is an aluminum nitride single phase as measured by an X-ray diffraction method. The aluminum nitride sintered body according to claim 1, comprising at least one of a cerium aluminate phase and a CeAl ₁₁ O ₁₈ phase and an aluminum nitride phase as measured by an X-ray diffraction method. The aluminum nitride sintered body according to claim 3, comprising at least one of a cerium aluminate phase and a CeAl ₁₁ O ₁₈ phase and an aluminum nitride phase as measured by an X-ray diffraction method. The aluminum nitride sintered body according to claim 4, comprising at least one of a cerium aluminate phase and a CeAl ₁₁ O ₁₈ phase and an aluminum nitride phase as measured by an X-ray diffraction method. At least one part is comprised by the aluminum nitride sintered compact of Claim 1, The member for semiconductor manufacture characterized by the above-mentioned. The member for manufacturing a semiconductor according to claim 22, wherein the semiconductor manufacturing member includes a substrate made of the aluminum nitride sintered body and a metal member embedded in the substrate. 24. The member of claim 23, wherein the metal member comprises at least an electrostatic chuck electrode.