JPH0878202A - Ceramic resistor - Google Patents

Abstract

PURPOSE: To obtain a resistor having small thermal variation by controlling the quantity of element of periodic table 4b group in aluminum nitride and lattice constant. CONSTITUTION: An aluminum nitride film, on which a periodic table 4b group element is, excessively solidified on the surface of a substrate consisting of an aluminum nitride sintered body, is compounded by a CVD method. As a result, a ceramic resistor, containing 0.005 to 30atom% of the element of 4b group on the periodic table, on which the lattice constant of aluminum nitride is shifted by 0.003 to 0.030 Angstrome on a-axis and 0.004 to 0.080 Angstrome on c-axis, can be obtained. Besides, the volume intrinsic resistance at 25 deg.C becomes 10<13> Ω/cm or smaller, and the volume intrinsic resistance becomes 10<13> to 10<11> Ω/cm in the temperature range from room temperature to 300 deg.C. Accordingly, the usefulness of the ceramic resistor is high when it is used for the electrostatic chuck of a semiconductor manufacturing device on which stabilized resistance is required for a wide temperature range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic resistor mainly composed of aluminum nitride, which is suitable for a heater material, a vacuum tube envelope, an antistatic material in a semiconductor manufacturing apparatus, a wafer transfer arm, a wafer handling jig and the like. Regarding

[0002]

2. Description of the Related Art Conventionally, as a method for adjusting the electric resistance of insulating ceramics, it has been generally practiced to add a conductive material to the insulating ceramics to control the resistance value. For example, titanium nitride is added to alumina to reduce the electric resistance.

On the other hand, aluminum nitride is a kind of non-oxidizing ceramics and is expected to be applied as a structural material or a high temperature material, and it has recently been reported that it has excellent durability against plasma resistance. There is. Therefore, application of this aluminum nitride as a component in a semiconductor manufacturing apparatus such as an electrostatic chuck is considered. However, this aluminum nitride itself is a highly insulating material, and even at room temperature, 1
At present, it has not been put into practical use because it has a resistance value of 0 ¹⁶ Ω-cm or more.

Even with respect to such aluminum nitride,
Attempts have been made to reduce the electrical resistance. For example, JP-A-56-4509 proposes that a conductive material such as Al is added to an insulating ceramic such as aluminum nitride or boron nitride to adjust the specific resistance. In the case of thin film ceramics, it is also possible to obtain a thin film resistor having a small temperature coefficient of resistance by dispersing metallic aluminum in aluminum nitride, for example.
Has been proposed in the issue.

[0005]

Generally, the volume resistivity of an insulator tends to decrease with temperature. For example, aluminum nitride has a resistivity of 10 ¹⁶ Ω-cm at room temperature.
To 300 ° C. to 10 ¹¹ Ω-cm or less. Therefore, when used from room temperature to a high temperature of 300 ° C., there is a problem that the operating temperature condition is limited because the resistance value changes and stable operation cannot be obtained.

Further, in the method of controlling the electric resistance by adding the conductive material, there is a problem that the characteristics originally possessed by the insulating ceramics are impaired due to the characteristics of the conductive material itself. For example, the corrosion resistance and durability were poor, and the properties of aluminum nitride were deteriorated.

[0007]

The inventors of the present invention have made repeated studies on the above problems from the viewpoints of composition and structure as a ceramic resistor having an electric resistance of 10 ¹³ Ω-cm or less. For example, an insulator mainly composed of aluminum nitride formed by a chemical vapor deposition method contains 0.005 to 30 atomic% of an element of the 4b group element group of the periodic table, and the element is an aluminum nitride crystal. The volume resistivity of the insulating layer is 10 ¹³ Ω− by controlling the lattice constant of aluminum nitride to be in a specific range by making a solid solution therein.
It has been found that the material properties can be adjusted to a range of cm or less, the temperature change is small, and stable material properties can be obtained in a wide temperature range, and the present invention has been accomplished.

That is, the ceramic resistor of the present invention is a ceramic resistor mainly composed of an aluminum nitride crystal phase, and the element of Group 4b of the periodic table is 0.005 in the resistor.
.About.30 atomic%, and the lattice constant in the crystal phase is a
It is a value shifted by 0.003 to 0.030 angstrom on the axis and 0.004 to 0.080 angstrom on the c-axis, and the volume resistivity at 25 ° C. is 10 ¹³ Ω-cm or less. To do.

The present invention will be described in detail below. The ceramic resistor in the present invention is mainly composed of aluminum nitride, but has a composition of 0.004 elements of Group 4b of the periodic table.
5 to 30 atom% is contained. This Periodic Table No. 4
The b-group element amount is an important element for imparting conductivity to aluminum nitride, and the element amount is 0.005
If it is less than 30% by atom, the desired resistance cannot be obtained.
If it exceeds the range, another crystal phase is likely to be generated, resistance control becomes difficult, and peeling and cracks are likely to occur in the thin film. The Group 4b element of the periodic table is specifically C, Si, Ge, Sn, Pb, and particularly C and S.
i is desirable in terms of film forming property.

This ceramic resistor is structurally
Although mainly composed of an aluminum nitride crystal, a part of the periodic table group 4b element in this resistor is solid-solved in the aluminum nitride crystal, but cannot be completely dissolved in this crystal. There may be a case where a crystal phase such as a nitride of the group 4b element group of the periodic table is present in a proportion of 20% by weight or less due to the group 4b element. The aluminum nitride crystal has a lattice constant of 0.003 to 0.030 angstroms on the a axis and 0.004 to 0.080 angstroms on the c axis from the lattice constant of aluminum nitride due to the solid solution of the Group 4b element of the periodic table. It is in the range of values shifted by a large amount or a small amount, and the lattice constant (a
Axis 3.120 angstroms, c-axis 4.994 angstroms), which have a clearly different lattice constant.

The ceramic resistor of the present invention has a volume resistivity of 10 ¹³ Ω-cm or less at 25 ° C. with the above structure, and its lower limit value is about 320 Ω-cm.
Is. Moreover, as is apparent from the examples described later, this resistor has a great feature that it has an excellent resistance stability in which the change with respect to the resistance value at 25 ° C. is 3 digits or less in the temperature range from room temperature to 300 ° C. is there. Also, -1
It has a resistance value that is the same as room temperature even at 00 ° C.

As a method for manufacturing the ceramic resistor of the present invention, the manufacturing method is not particularly limited as long as the above-mentioned constitution is satisfied, but the vapor phase growth method is particularly preferable in view of the ease of manufacturing. Preferably, specifically, a physical vapor phase synthesis method (PVD method) such as sputtering or ion plating, plasma CVD, photo CVD, MO (M
It is formed by a chemical vapor deposition method (CVD method) such as metal-organic CVD.
The VD method is good. According to these film forming methods,
A ceramic which can synthesize aluminum nitride in which a group b element is excessively solid-solved and which contains 0.01 to 30 atom% of a group 4b element of the periodic table adopted by the present invention and whose lattice constant of an aluminum nitride crystal is changed. A resistor can be obtained.

Si is selected as a Group 4b element of the periodic table, and a specific manufacturing method using the CVD method is as follows: N ₂ gas, NH ₃ gas, SiCl ₄ and AlC as raw material gas.
L ₃ gas is used, and the flow rate ratio of these gases is N ₂ / AlC.
l ₃ = 5-70, SiCl ₄ / NH ₃ = 0.001-
3, NH ₃ / AlCl ₃ = 0.1 to 10 and the film forming temperature is set to a relatively high temperature of 850 ° C. or higher. SiHC instead of SiCl ₄
l ₃ , SiH ₂ Cl ₂ , SiH ₄ , Si ₂ H ₆ or the like may be used, and instead of AlCl ₃ , a halide such as AlBr or an organic aluminum such as trimethylaluminum may be used.

On the other hand, as the substrate for forming the film, any substrate can be used, but specifically, Al ₂ O ₃ and AlO are used.
N, Si ₃ N ₄ , diamond, mullite, ZrO ₂ ,
Examples include W, Mo, Mo-Mn, TiN, SiC, WC, carbon, and Si semiconductor materials (n-type or p-type). Among these, a sintered body mainly composed of aluminum nitride is the most suitable in consideration of adhesion. desirable.

[0015]

[Function] Normally, aluminum nitride has a volume resistivity of 10 ¹⁴
Although it is a high insulator exceeding Ω-cm, when a group 4b element of the periodic table is dissolved in the aluminum nitride crystal and aluminum or nitrogen is replaced by the group 4b element of the periodic table, it acts as a donor or an acceptor. It is considered that it contributes to conductivity and acts to increase the conductivity of the crystal. Further, the solid solution of the group 4b element of the periodic table in the aluminum nitride crystal can be determined by the change in the lattice constant. For example, the lattice constant of aluminum nitride containing no group 4b element of the periodic table is 3.120 angstroms on the a-axis and 4.9 on the c-axis.
Although it was 94 Å, both the a-axis and the c-axis change as the Group 4b element of the Periodic Table becomes a solid solution. The lattice constant is 0.003 to 0.03 on the a-axis from these values.
The volume resistivity can be controlled to 10 ¹³ Ω-cm or less by setting the value to 0 angstrom and a value shifted to a larger or smaller value by 0.004 to 0.080 angstrom on the c-axis.

Further, the ceramic resistor of the present invention has a small resistance change with temperature. For example, in the case of general aluminum nitride, 10 ¹⁶ Ω-cm to 10 ¹¹ Ω-in the temperature range from room temperature (25 ° C.) to 300 ° C. While it varies up to cm, in the ceramic resistor of the present invention, for example, 1
It has a characteristic that it changes from 0 ¹³ Ω-cm to 10 ¹¹ Ω-cm by 3 digits or less, and -10
It maintains the volume resistivity with a small change rate even at a low temperature of 0 ° C.

Therefore, it is particularly useful for applications such as electrostatic chucks in semiconductor manufacturing equipment that require stable resistance over a wide temperature range.

[0018]

【Example】

Example 1 An AlN film was formed on the surface of a substrate made of an aluminum nitride sintered body by a chemical vapor deposition method. The AlN film is formed by placing the substrate in a furnace heated to 900 ° C. by an external heating method, nitrogen 8 SLM, ammonia 1 SLM, 0 to 0.
Flowing 5 SLM of SiCl4 gas to raise the pressure to 50 torr
And Further, aluminum chloride (AlCl ₃ ) was introduced at a flow rate of 0.3 SLM to start the reaction, and
A film having a thickness of m was formed (Sample Nos. 1 to 9).

The obtained film was analyzed by X-ray diffraction to obtain Si (S
The angle was corrected using RM640b) as a standard sample, and the peak top method was used for calculation. The measurement plane index is (100),
(002), (101), (102), (110),
The values were (103), (112), and (004). Also,
The volume resistivity at −100 ° C., room temperature and 300 ° C. was measured and shown in Table 1. In addition, No. 5 of -100 to 600
The volume resistivity at ° C is shown in Fig. 1.

Example 2 An AlN film was formed on the surface of a substrate made of an aluminum nitride sintered body by a chemical vapor deposition method. The AlN film is formed by placing the substrate in a furnace heated to 900 ° C. by an external heating method, nitrogen 8 SLM, ammonia 1 SLM, 0 to 0.
CH ₄ of _{5SLM, GeH 4, SnCl 4,} Pb (CH
₃ ) ₄ gas was flowed to adjust the pressure to 50 torr. Further, aluminum chloride (AlCl ₃ ) was introduced at a flow rate of 0.3 SLM to start the reaction, and a film having a thickness of about 400 μm was formed (Sample No. 10 to 13). The lattice constant of the obtained film was calculated by the X-ray diffraction method as in Example 1, and the volume resistivity at −100 ° C., room temperature and 300 ° C. was measured, and the results are shown in Table 1.

[0021]

[Table 1]

[0022] As apparent from the results of Table 1 sample Nanba1～9, Si atomic weight and the lattice constant of nitride in the aluminum changes by SiCl ₄ flow rate, without any introduction of SiCl _4, Si atomic amount impurity levels In the case of 0.0001 at%, the volume resistivity was 9 × 10 ¹⁵ Ω-cm, which was highly insulating, but the amount of Si atoms in the film increased as the flow rate of SiCl ₄ was gradually increased. At the same time, the lattice constant gradually decreased, but the film of Sample No. 9 had a silicon nitride phase as a main phase. The obtained aluminum nitride film was an AlN film oriented in (002) according to X-ray diffraction measurement. However, a transmission electron microscope observation shows that there is a silicon nitride crystal phase, and the amount thereof is SiC.
There was a correlation with the l ₄ flow rate.

For elements of Group 4b of the periodic table other than Si, the atomic weight and lattice constant of the element of Group 4b of the periodic table in aluminum nitride change depending on the flow rate of the additive gas containing the element of Group 4b of the periodic table. As the flow rate of the additive gas containing the group 4b element of the periodic table was gradually increased, the amount of the group 4b element of the periodic table in the film increased, the lattice constant also gradually changed, and the volume resistivity decreased. . The obtained aluminum nitride film was an AlN film oriented in (002) according to the X-ray diffraction measurement, and there was also a film having no nitride crystal phase.

[0024]

As described above in detail, according to the present invention, the volume resistivity at room temperature is 10 ¹³ Ω-cm or less by controlling the amount of the Group 4b element in the periodic table and the lattice constant in aluminum nitride. It is possible to obtain a resistor whose temperature change is small. Therefore, the characteristics of aluminum nitride,
For example, the resistance value can be changed without losing the corrosion resistance.

[Brief description of drawings]

FIG. 1 is a sample No. It is a figure which shows the change of the volume specific resistance of No. 5 of -100 degreeC-600 degreeC.

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Claims (2)

[Claims] 1. A ceramic resistor mainly composed of an aluminum nitride crystal phase, in which 0.005 to 30 atom% of a Group 4b element of the periodic table is present in the resistor, and the lattice constant in the crystal phase is From the lattice constant of aluminum nitride single phase a
The value is shifted by 0.003 to 0.030 angstrom on the axis and 0.004 to 0.080 angstrom on the c axis, and the volume resistivity at 25 ° C. is 1
A ceramic resistor having a resistance of 0 ¹³ Ω-cm or less. 2. The ceramic resistor according to claim 1, wherein the resistor is formed by a chemical vapor deposition method.