JP3389514B2 - Aluminum nitride sintered body, method of manufacturing the same, and member for semiconductor manufacturing apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum nitride sintered body which is excellent in corrosion resistance and plasma resistance and has very few particles generated, a method for producing the same, and a vacuum chamber using the aluminum nitride sintered body as a base material. The present invention relates to a member for a semiconductor manufacturing apparatus such as a wall material, a high frequency transmission window, a clamp ring, a lift pin, an electrostatic chuck for holding a semiconductor wafer, a heater, and a susceptor.

[0002]

2. Description of the Related Art A wafer holding member such as a susceptor for supporting a semiconductor wafer, an electrostatic chuck, a heater or the like, or a wafer holding member installed in a vacuum chamber in a film forming apparatus or an etching apparatus in a semiconductor device manufacturing process. In addition, a supporting member for supporting the vacuum chamber, an inner wall material of a vacuum chamber, a shadow ring, a clamp ring, a dome for generating a high frequency plasma, a high frequency transmission window, a lift pin for lifting a semiconductor wafer, etc. are used. Among them, the wafer holding member, the clamp ring, the lift pin, etc., which come into direct contact with the semiconductor wafer are made of ceramics such as alumina sintered body and silicon nitride sintered body, and other members are generally made of stainless steel or aluminum. It was formed of metal such as quartz or quartz glass.

By the way, during the film forming process or the etching process, a highly corrosive halogen gas such as chlorine or fluorine is used as a deposition gas, an etching gas, and a cleaning gas. It is also performed to generate plasma. And, the members for semiconductor manufacturing equipment made of materials such as stainless steel, aluminum, and quartz glass are severely worn or corroded when exposed to plasma or halogen gas at high temperature to generate particles, which lowers the yield of semiconductor devices. In addition, the film forming apparatus and the etching apparatus have a problem in that maintenance such as cleaning must be performed in a short cycle, resulting in poor operation efficiency. In particular, since stainless steel generates particles containing iron, the iron also contaminates the semiconductor wafer.

On the other hand, although a member for semiconductor manufacturing equipment made of ceramics can significantly suppress the generation of particles as compared with a member made of metal or glass, it is insufficient in a semiconductor manufacturing process requiring a super clean state. Met.

Therefore, as a result of research on a material suitable for a member for a semiconductor manufacturing apparatus, the aluminum nitride sintered body has plasma resistance, corrosion resistance to halogen gas, and high heat conduction characteristics. It is known today that it is superior to the above ceramics as a member for semiconductor manufacturing equipment, and as such an aluminum nitride sintered body, an aluminum nitride sintered body containing a metal such as yttrium or a rare earth element, or carbon of 500 p
An aluminum nitride sintered body containing pm or more has been proposed (see JP-A-9-48668).

[0006]

However, the aluminum nitride sintered body containing the metal has a problem that even if the metal content is small, it is diffused into the semiconductor wafer to cause defects. .

On the other hand, although the aluminum nitride sintered body containing a relatively large amount of carbon does not contaminate the semiconductor wafer like a metal component, it has a problem that many particles are generated.

That is, the carbon contained in the aluminum nitride sintered body is unevenly distributed in the grain boundaries, but when contacted with a halogen gas or a gas which is made into plasma, these gases react with the carbon existing in the grain boundaries. Since it is removed outside the sintered body, the part where carbon was present becomes a void, and it becomes easy to be attacked by halogen gas or plasmaized gas, so corrosion and wear progress from this void. As a result, there is a problem in that the aluminum nitride particles are shattered, and the shredded powder becomes particles and adheres to and deposits on the semiconductor wafer, which adversely affects the semiconductor wafer.

Further, in order to remove the carbon which is the cause of the grain removal, the aluminum nitride sintered body is heat-treated in an oxidizing atmosphere so that carbon and oxygen are reacted with each other, and CO,
Although it may be considered to remove it as a gas such as CO ₂ , the amount of the gas can be treated only at the extreme surface layer of about 1 μm at most, and a sufficient effect could not be obtained.

On the other hand, the applicant of the present application has previously proposed a corrosion-resistant member made of a high-purity aluminum nitride sintered body having an aluminum nitride content of 99.8% by weight or more (special feature). See Kaihei 8-208338).

That is, since the impurity metal and carbon are extremely small in the high-purity aluminum nitride sintered body, the corrosion resistance and plasma resistance to the halogen gas are excellent, and the pure aluminum nitride crystal is, for example, chlorine-based gas. When it reacts, it becomes aluminum chloride, which sublimes and is removed outside the vacuum chamber, which has the advantage of not contaminating the semiconductor wafer.

However, in recent years, it has been pointed out that the problem of particles is caused even in the member for semiconductor manufacturing equipment made of a high-purity aluminum nitride sintered body in the manufacturing process of semiconductor equipment which requires an ultra-super clean state. There was a demand for the one with less occurrence.

[0013]

In view of the above problems, therefore, the aluminum nitride sintered body according to the present invention is such that the elements present in the sintered body are substantially composed of Al, O and N,
The main crystal phase is aluminum nitride, the other crystal phases are Al ₉ N ₇ O ₃ and / or Al ₁₀ N ₈ O ₃ , and the relative density with respect to the theoretical density is 95% or more. To do. Further, the present invention provides X-ray diffraction (source of X-rays: copper) of the aluminum nitride sintered body,
Diffraction peak intensity I _{1 of} aluminum nitride which is the main crystal phase
The intensity ratio (I ₂ / I ₁ ) between the (plane spacing: 2.68 to 2.70) and the diffraction peak intensity I ₂ of another crystal phase (plane spacing: 2.41 to 2.44) is 1% or more. Is characterized in that. Furthermore, the aluminum nitride sintered body according to the present invention,
It is characterized in that the amount of carbon contained in the sintered body is 500 ppm or less.

Further, the present invention is characterized in that the above aluminum nitride sintered body is used as a base material of a member for a semiconductor manufacturing apparatus.

Furthermore, according to the present invention, the aluminum nitride powder is mixed with aluminum oxide powder and carbon or a substance capable of forming carbon during firing, and the mixture is molded into a predetermined shape, and then the mixture is formed in a nitrogen stream at 1900 ° C. or higher and It is characterized in that an aluminum nitride sintered body is manufactured by firing at a gas pressure of 0.5 MPa or more.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

In the aluminum nitride sintered body of the present invention, the elements present in the sintered body are substantially composed of Al, O, N, and contain almost no impurity metals or carbon, and the main crystal phase is nitrided. Made of aluminum and the other crystal phase is Al ₉ N ₇ O
₃ and / or Al ₁₀ N ₈ O ₃ . That is, since the aluminum nitride sintered body of the present invention contains almost no impurity metals such as alkali metals, heavy metals, rare earth metals, etc., it may contaminate a semiconductor wafer even when used as a member for a semiconductor manufacturing apparatus. In addition, since the main crystal phase is made of aluminum nitride, which has excellent corrosion resistance to halogen gas and plasma resistance to plasma, it contains almost no impurity metals or carbon that promote corrosion by halogen gas or abrasion by plasma. The corrosion resistance and plasma resistance of the aluminum nitride sintered body can be improved.

In the present invention, the fact that the elements present in the sintered body consist essentially of Al, O and N is A
Impurity metal which is a component other than 1, O, N is 0.5% by weight
The following, preferably 0.1% by weight or less,
It means that carbon is 500 ppm or less, preferably 300 ppm or less.

Further, the aluminum nitride sintered body of the present invention is excellent in corrosion resistance against halogen gas and plasma resistance to plasma as other crystal phases other than aluminum nitride, which is the main crystal phase, as well as aluminum nitride. Since the crystal structure has columnar Al ₉ N ₇ O ₃ crystals and / or Al ₁₀ N ₈ O ₃ crystals, the generation of particles can be greatly reduced.

That is, since the main crystal phase of aluminum nitride has a substantially spherical crystal structure, if the crystal phase in the sintered body is composed of only aluminum nitride, it will not be corroded by halogen gas or plasma. When abraded, the aluminum nitride particles are likely to be shattered, and the shredded powder becomes particles. In the present invention, as shown in FIG. 1, columnar Al ₉ N ₇ O ₃ is formed in a substantially spherical aluminum nitride crystal. Crystal and / or Al ₁₀ N ₈ O ₃ crystal is allowed to exist so that a substantially spherical aluminum nitride crystal and a columnar Al ₉ N ₇ O ₃ crystal and / or Al ₁₀ N ₈ crystal are present.
O ₃ crystals have a structure in which they are entangled with each other, and it is possible to have a structure in which grain removal does not easily occur even when corroded or abraded by a halogen gas or plasma, so that it is possible to significantly reduce the generation of particles.

Al ₉ N ₇ O ₃ crystals and / or Al ₁₀ N ₈
The presence of O ₃ crystals can be confirmed by examining the presence or absence of a peak due to X-ray diffraction (X-ray generation source: copper).
That is, Al ₉ N ₇ O ₃ has a 2θ of 34.7 to 35.2 degrees (plane spacing: 2.55 to 2.58) and a 2θ of 36.8 to 3 °.
It has peaks at both positions of 7.2 degrees (plane spacing: 2.41 to 2.44), and Al ₁₀ N ₈ O ₃ has 2θ of 3
6.8 to 37.2 degrees (spacing: 2.41 to 2.44)
Has a peak at the position. Therefore, the presence or absence of the Al ₉ N ₇ O ₃ crystal or the Al ₁₀ N ₈ O ₃ crystal in the aluminum nitride sintered body is confirmed by checking the presence or absence of the diffraction peak intensity at the position where the plane spacing is 2.41 to 2.44. Can be confirmed.

In the present invention, at least Al ₉ N _{7 is used.}
One of O ₃ crystal or Al ₁₀ N ₈ O ₃ crystals may exist even in a small amount, but preferably, the diffraction peak strength of the aluminum nitride is a predominant crystal phase I ₁ (lattice spacing:
2.68 to 2.70) and another crystalline phase of Al ₉ N ₇
Diffraction peak intensity I of O ₃ and / or Al ₁₀ N ₈ O _3
2 (plane spacing: 2.41 to 2.44) and the intensity ratio (I ₂
/ I ₁ ) is preferably 1% or more, and by setting the strength ratio within this range, the generation of particles can be further reduced.

Further, in order to enhance the plasma resistance, it is necessary to be as dense as possible, and it is desirable that the relative density with respect to the theoretical density is 95% or more. The relative density of the aluminum nitride sintered body can be calculated by the following formula, and the bulk density is measured by the Archimedes method.

(Formula) Relative density = (Sintered body density / 3.26) * 100 However, the theoretical density is set to 3.26 g / cm ³ since a sintering aid having a large density is not included.

When the proportion of Al ₉ N ₇ O ₃ crystals or Al ₁₀ N ₈ O ₃ crystals in the sintered body increases,
Although it is possible to effectively prevent shedding due to halogen gas or plasma, the thermal conductivity, which is an excellent feature of the aluminum nitride sintered body, is reduced. Therefore,
The content of aluminum nitride in the aluminum nitride sintered body is 70 in order not to significantly impair the thermal conductivity.
It is preferably at least wt%, more preferably at least 80 wt%, and such an aluminum nitride sintered body can have a thermal conductivity of 50 W / mK or more.

Next, a method of manufacturing the aluminum nitride sintered body of the present invention will be described.

First, a high-purity aluminum nitride powder having an amount of an impurity metal such as an alkali metal, a heavy metal, or a rare earth metal of 1000 ppm or less is prepared. Then, with respect to this aluminum nitride powder, Al ₉ N ₇ O ₃ crystals and / or
Alternatively, aluminum oxide powder is added as an oxygen source in order to generate Al ₁₀ N ₈ O ₃ crystals and adjust the amount of oxygen in the sintered body, and carbon is added in order to adjust the amount of oxygen in the sintered body. Such carbon or a substance capable of forming carbon upon firing is added. Here, it is also possible to use a binder described later as a substance that produces carbon during firing.
It should be noted that the amount of oxygen in the sintered body is adjusted to 5% by weight or less in the preparation.

Then, a binder is added to this mixed raw material, and the mixture is uniformly mixed with a solvent, dried and sieved to produce granulated powder. Then, the granulated powder is filled in a mold and molded into a predetermined shape by a uniaxial pressure molding method or an isopressurization molding method. At this time, the molded body may be cut.

Thereafter, the molded body is degreased in a nitrogen stream and then sintered in a nitrogen stream at a temperature of 1900 ° C. or higher. The gas pressure at this time is 0.5 MPa or more.

Here, the firing temperature is set to 1900 ° C. or higher because if it is lower than 1900 ° C., the densification is not promoted sufficiently, the relative density becomes lower than 95%, and many pores exist in the sintered body. Therefore, the corrosion resistance and the plasma resistance are significantly reduced, and the generation of particles cannot be sufficiently suppressed. Moreover, the gas pressure is 0.5 MPa.
The reason is that if the pressure is lower than 0.5 MPa, Al ₉ N ₇ O ₃ crystals or Al ₁₀ N ₈ O ₃ crystals cannot be generated in the sintered body, and the generation of particles can be sufficiently suppressed. Because you can't.

As a means for forming the molded body, tape molding such as a casting molding method or a doctor blade method may be used in addition to the above-mentioned uniaxial pressure molding method and isopressurization molding method.

Next, an example in which a heater built-in electrostatic chuck is applied as an example of a member for a semiconductor manufacturing apparatus using the aluminum nitride sintered body of the present invention will be described.

The heater built-in electrostatic chuck 1 shown in FIGS. 2 (a) and 2 (b) is composed of a disk-shaped plate-shaped ceramic body 2, and the elements present in the sintered body are substantially Al,
It consists of only O and N, aluminum nitride is the main crystal phase, and other crystal phases are Al ₉ N ₇ O ₃ and / or Al ₁₀ N ₈
It is made of an aluminum nitride sintered body made of O ₃ .

The upper surface of the plate-shaped ceramic body 2 serves as a mounting surface 3 for holding the semiconductor wafer W. Further, in the plate-shaped ceramic body 2, the mounting surface 3 side is used for electrostatic adsorption. The electrode 4 and the heater electrode 5 are embedded respectively. In addition, 6 is a power supply terminal electrically connected to the electrode 4 for electrostatic attraction, and 7 is a power supply terminal electrically connected to the electrode 5 for a heater.

In order to attract the semiconductor wafer W by the electrostatic chuck 1, first, the semiconductor wafer W is placed on the placement surface 3, and then the semiconductor wafer W and the electrode 4 for electrostatic attraction are placed. When a DC voltage is applied to the semiconductor wafer W, a Coulomb force due to dielectric polarization or a Johnson-Rahbek force due to a minute leak current is developed, and the semiconductor wafer W is forcibly attracted and fixed onto the mounting surface 3. And
Under this condition, the semiconductor wafer W can be uniformly heated by energizing the electrode 5 for the heater to heat the electrostatic chuck 1.

The heater built-in electrostatic chuck 1 is also provided.
Is exposed to halogen gas under high temperature plasma in the vacuum chamber.
The aluminum nitride sintered body that forms the Al ₉ N ₇ O having a corrosion resistance and a plasma resistance similar to that of aluminum nitride as the other crystal phase other than the main crystal phase of aluminum nitride.
_{Since it has 3} and / or Al ₁₀ N ₈ O ₃ , it has a structure which hardly corrodes or wears even in such a severe atmosphere, and has a structure in which crystal grain formation is unlikely to occur. The generation of particles is small, the film formation process and the etching process of the semiconductor wafer W are not adversely affected, and the semiconductor wafer W is not contaminated because almost no impurity metal is contained.

Although the heater built-in electrostatic chuck 1 is shown as an example of a member for a semiconductor manufacturing apparatus using the aluminum nitride sintered body of the present invention as a base material, another susceptor is used as a wafer holding member for holding a semiconductor wafer. It can also be applied to a ceramic heater, a supporting member for installing the wafer holding member in the vacuum chamber, an inner wall material of the vacuum chamber, a shadow ring, a clamp ring, a dome for generating a high frequency plasma, and a high frequency transmission. It can also be applied to semiconductor manufacturing equipment members such as windows and lift pins for lifting semiconductor wafers. By using the aluminum nitride sintered body of the present invention for these members, the generation of particles that adversely affect the semiconductor wafer is significantly reduced. Can be suppressed to.

[0038]

Example 1 As a starting material, an aluminum nitride powder having an average particle size of 1.5 μm, an oxygen content of 0.8%, and a carbon content of 300 ppm manufactured by an alumina reduction nitriding method was used. In addition, when the amount of impurity metals was examined, Ca was 300 ppm or less, and in addition, Si, Fe,
The content of each metal such as Na and Ti was 100 ppm or less.

A sintering aid was not added to this aluminum nitride powder, and the average particle size as an oxygen source was 1.5.
aluminum oxide powder having a purity of 99.9%, which is μm,
Carbon black (average particle size 0.5 μm, purity 99%) was added to adjust the amount of oxygen in the sintered body, and an organic binder and solvent were mixed and mixed at 60 ° C.
And dried to produce granulated powder. Next, this granulated powder is filled in a mold and molded into a disk shape at a molding pressure of 1 ton / cm ² , and then degreased in a nitrogen stream, and then the firing conditions are changed to obtain Al ₉ Manufacture aluminum nitride sintered bodies having N ₇ O ₃ crystals and / or Al ₁₀ N ₈ O ₃ crystals and those not having, and different relative densities,
Experiments were carried out to examine the corrosion resistance and plasma resistance when exposed to halogen gas under plasma and the state of particle generation.
For comparison, the content of aluminum nitride is 99.
An 8% high-purity aluminum nitride sintered body was also prepared and the same experiment was conducted.

Regarding the corrosion resistance and the plasma resistance, the weight of a 1 cm square sample was first measured, and then the sample was heated to 700 ° C.
After being heated to 100 ° C. and exposed to 100% chlorine gas under plasma for 96 hours, the weight was measured again and the weight reduction amount was used to evaluate the corrosion resistance and plasma resistance.

Regarding the generation of particles, a 1 cm square sample was placed at the center of a 6 inch silicon wafer, plasma was generated under 100% chlorine gas, and the treatment was performed at a temperature of 700 ° C. for 5 minutes. After that, the sample was removed, and particles of 0.2 μm or more attached to the wafer were measured by a particle counter and evaluated.

Regarding the characteristics of the aluminum nitride sintered body, the relative density was calculated by measuring the density of the sintered body by the Archimedes method and calculating the theoretical density at 3.26 g / cm.
^{It was set to 3} and calculated by the following formula.

(Formula) Relative density = (Sintered body density / 3.26) * 100 Further, Al ₉ N ₇ in the aluminum nitride sintered body is used.
Regarding the presence or absence of O ₃ crystal or Al ₁₀ N ₈ O ₃ crystal, X-ray diffraction (source of X-ray: copper) showed a plane spacing of 2.41.
It was judged based on whether or not there is a peak at the positions of to 2.44.

The respective results are shown in Table 1.

[0045]

[Table 1]

As a result, first, the sample No. In Nos. 1 and 2, the relative density was low, a large number of pores were present in the sintered body, and therefore the amount of weight reduction was large, and particles were often generated. In addition, the sample No. Nos. ₆ and ₇ have no Al ₉ N ₇ O ₃ crystals or Al ₁₀₀ N ₈ O ₃ crystals in the aluminum nitride sintered body, so that the number of particles is 70 or more, and it is possible to sufficiently suppress the generation of particles due to shedding. There wasn't.

Furthermore, the sample No. of the comparative example was used. Sample No. 15 had relatively high corrosion resistance and plasma resistance due to its high purity, but the number of particles was 92, and the generation of particles due to shedding could not be sufficiently suppressed.

On the other hand, the sample No. 3-5 and 8-1
No. 4 has Al ₉ N ₇ O ₃ crystals and / or Al ₁₀ N ₈ O ₃ crystals in the aluminum nitride sintered body and has a relative density of 95% or more, the weight reduction amount is 10% by weight.
The number of particles was 15 or less, and the number of particles generated was 15 or less, which was excellent. Among these, sample N
o. As can be seen in Nos. 4, 8 and 14, if the relative densities are the same, the diffraction peak intensity I ₁ (interplanar spacing: 2.68 to 2.70) of aluminum nitride which is the main crystal phase and the other crystal phases Diffraction peak intensity I ₂ (plane spacing: 2.41 to 2.4
By setting the intensity ratio (I ₂ / I ₁ ) with ₄ ) to 1% or more, the number of particles can be 10 or less, and the generation of particles can be further suppressed.

Example 2 Next, as in Example 1, as a starting material, an average particle size of 1.5 μm, an oxygen content of 0.8% and a carbon content of 3 produced by an alumina reduction nitriding method were used.
An aluminum nitride powder of 00 ppm was prepared, and a sintering aid was not added to the aluminum nitride powder, and an aluminum oxide powder having an average particle size of 1.5 μm and a purity of 99.9% and carbon black (average particle size 0 0.5 μm, purity 99%) was added, and an organic binder and a solvent were further mixed and mixed, and then dried at 60 ° C. to produce granulated powder. Next, this granulated powder was filled in a mold and 1 ton / cm ²
It is molded into a disk shape at a molding pressure of, and then degreased in a nitrogen stream, and then in a nitrogen stream of 0.5 MPa or more.
Samples having different carbon contents in the aluminum nitride sintered body were manufactured by firing at a temperature of 00 ° C. or higher, and corrosion resistance, plasma resistance, and generation of particles were performed under the same conditions as in Example 1. A measurement experiment was conducted.

The aluminum nitride sintered bodies constituting each sample were made to have a relative density of 97% and an oxygen content of 1.5% by weight.

The respective results are shown in Table 2.

[0052]

[Table 2]

As a result, first, the sample No. 21-23, when the amount of carbon in the sintered body is more than 500 ppm, Al ₉ N ₇ O ₃ crystals and Al ₁₀ N are contained in the sintered body.
₈ O ₃ crystals could not be generated and the weight loss was 1
The amount was slightly higher than 0% by weight, and the amount of particles generated was 40 or more, and there was no effect of sufficiently suppressing the generation of particles.

On the other hand, sample No. 24 to 26, the amount of carbon in the aluminum nitride sintered body is 500 ppm
By the following, an Al ₉ N ₇ O ₃ crystal and / or an Al ₁₀ N ₈ O ₃ crystal can be generated in the sintered body, and the presence of these crystals excels in corrosion resistance and plasma resistance. The generation of particles could be greatly reduced.

From this, the amount of carbon during sintering is 5
It was confirmed that the amount should be less than 00 ppm.

Example 3 An experiment for producing an aluminum nitride sintered body was conducted under the same conditions as in Example 1 except that the firing temperature and gas pressure during firing were changed. The amount of aluminum oxide powder added was 2% by weight, and the amount of carbon black added was 0.2% by weight.

The respective results are shown in Table 3.

[0058]

[Table 3]

As a result, the sample No. When the firing temperature was less than 1900 ° C. as in Nos. 31 and 32, the densification could not be sufficiently achieved, and the relative density of the aluminum nitride sintered body could not be 95% or more.

On the other hand, even if the firing temperature is 1900 ° C. or higher, the sample No. 36, 37, gas pressure is 0.5 MPa
When it is lower, Al ₉ N ₇ O _{3 is} contained in the aluminum nitride sintered body.
Crystals or Al ₁₀ N ₈ O ₃ crystals could not be generated.

On the other hand, the sample No. 33-35 and 3
As shown in Nos. 8 to 42, by setting the firing temperature to 1900 ° C. or higher and the gas pressure to 0.5 MPa or higher, Al ₉ N ₇ O ₃ crystals and / or Al ₁₀ are contained in the aluminum nitride sintered body.
N ₈ O ₃ crystals could be generated, and the relative density of the sintered body could be 95% or more.

From this, the firing condition is 1900.
It has been confirmed that it is necessary to set the gas pressure to 0.5 MPa or more in a nitrogen stream at a temperature of ℃ or more.

(Example 4) Furthermore, the sample No. Four
Aluminum nitride sintered body of the present invention in Table 1 and sample No. 1 in Table 1. An electrostatic chuck 1 with a built-in heater having a diameter of about 170 mm shown in FIG. 2 is manufactured from an aluminum nitride sintered body outside the scope of the present invention in 6 and a 6 inch silicon wafer is attracted and held by this electrostatic chuck 1. Particles of 0.2 μm or more attached to the front and back surfaces of the silicon wafer after generating plasma in a state where the heater electrode 5 is heated to 500 ° C. and exposed to 100% chlorine gas for 20 hours. The generated amount of was compared. This work was repeated 5 times.

The respective results are shown in Table 4.

[0065]

[Table 4]

As can be seen from these results, the amount of particles adhering to the silicon wafer can be significantly reduced by using the electrostatic chuck 1 manufactured from the aluminum nitride sintered body of the present invention.

In this experimental example, the electrostatic chuck was used as an example of the member for the semiconductor manufacturing apparatus, but the generation of particles could be greatly suppressed even with other members.

[0068]

As described above, in the aluminum nitride sintered body according to the present invention, the elements present in the sintered body are substantially A.
aluminum nitride as a main crystal phase and the other crystal phases are Al ₉ N ₇ O ₃ and / or Al ₁₀ N ₈
O ₃ and 95% relative density to theoretical density
From the above, it is possible to significantly reduce the generation amount of particles because the structure is excellent in corrosion resistance against halogen gas and plasma resistance, and the crystal structure is less likely to cause shedding.

Further, by constructing a member for a semiconductor manufacturing apparatus by the aluminum nitride sintered body of the present invention, a semiconductor device of good quality can be manufactured with a good yield without contaminating the semiconductor wafer or causing defects. At the same time, the number of maintenances of the film forming apparatus and the etching apparatus can be reduced, so that the operating efficiency of the apparatus can be improved.

Furthermore, according to the present invention, aluminum nitride powder is mixed with aluminum oxide powder and carbon or a substance capable of forming carbon during firing, and the mixture is molded into a predetermined shape, and then, under a nitrogen stream at 1900 ° C. or higher. And 0.5M
Since the aluminum nitride sintered body is manufactured by firing at a gas pressure of Pa or higher, the elements existing in the sintered body are substantially composed of Al, O, N,
Aluminum nitride is the main crystal phase and the other crystal phases are Al ₉
It is possible to stably manufacture an aluminum nitride sintered body which is N ₇ O ₃ and / or Al ₁₀ N ₈ O ₃ and has a relative density of 95% or more relative to the theoretical density.

[Brief description of drawings]

FIG. 1 is a schematic view showing a crystal structure of an aluminum nitride sintered body according to the present invention.

2A and 2B are views showing an electrostatic chuck with a built-in heater, which is an example of a member for a semiconductor manufacturing apparatus, which is based on the aluminum nitride sintered body according to the present invention, in which FIG. 2A is a perspective view and FIG. It is the XX sectional view taken on the line of (a).

[Explanation of symbols]

1-Heater built-in electrostatic chuck 2 ... Plate-shaped ceramic body 3 ... Placement surface 4 Electrodes for electrostatic attraction 5 ... Electrode for heater 6, 7 ... Power supply terminal W: Semiconductor wafer

Claims (5)

(57) [Claims] 1. An element existing in a sintered body is substantially Al,
It consists of only O and N, aluminum nitride is the main crystal phase, and other crystal phases are Al ₉ N ₇ O ₃ and / or Al ₁₀ N ₈ O ₃
A is, the surface presence pillars <br/> like Al ₉ N ₇ O ₃ crystals and / or Al ₁₀ N ₈ O ₃ crystal in a substantially aluminum nitride crystal spherical
An aluminum nitride sintered body having an existing structure and having a relative density with respect to a theoretical density of 95% or more. 2. In the X-ray diffraction (source of X-rays: copper) of the aluminum nitride sintered body, the diffraction peak intensity I ₁ of the main crystal phase of aluminum nitride (interplanar spacing: 2.68 to 2.70). ) To the other crystal phase diffraction peak intensity I ₂
(Plane spacing: 2.41 to 2.44) intensity ratio (I ₂ /
The aluminum nitride sintered body according to claim 1, wherein I ₁ ) is 1% or more. 3. The aluminum nitride sintered body according to claim 1, wherein the amount of carbon contained in the aluminum nitride sintered body is 500 ppm or less. 4. A member for a semiconductor manufacturing apparatus, which uses the aluminum nitride sintered body according to any one of claims 1 to 3 as a base material. 5. An aluminum nitride powder is mixed with aluminum oxide powder and carbon or a substance capable of forming carbon upon firing, shaped into a predetermined shape, and then under a nitrogen stream at 1900 ° C. or higher and 0.5 MPa or higher. The method for producing an aluminum nitride sintered body according to any one of claims 1 to 3 , wherein the firing is performed at the gas pressure of.