JP3145575B2 - Ceramic resistor - Google Patents

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 suitable for a heater material, a charge removing material in a vacuum tube envelope or a semiconductor manufacturing apparatus, a wafer transfer arm, a wafer handling jig, and the like. About.

[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 used as a structural material or a high-temperature material. Recently, it has been reported that aluminum nitride has excellent durability against plasma. I have. Therefore, application of this aluminum nitride as a part in a semiconductor manufacturing apparatus such as an electrostatic chuck is considered. However, this aluminum nitride itself is a highly insulating material,
At present, it has not been put to practical use because it has a resistance value of 0 ¹⁶ Ω-cm or more.

[0004] With respect to such aluminum nitride,
Attempts have been made to reduce electrical resistance. For example, JP-A-56-4509 proposes to add a conductive material such as Al 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, for example, aluminum nitride.
No. has been proposed.

[0005]

In general, the volume resistivity of an insulator tends to decrease with temperature. For example, in the case of aluminum nitride, it is 10 ¹⁶ Ω-cm at room temperature.
At 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 a stable operation cannot be obtained due to a change in the resistance value, so that there is a limitation on a use temperature condition.

In addition, the method of controlling the electric resistance by adding a conductive material has a problem that the characteristics inherent to the insulating ceramic are impaired by the characteristics of the conductive material itself. For example, corrosion resistance and durability were lacking, and characteristics of aluminum nitride were deteriorated.

[0007]

[Means for Solving the Problems] The present inventors have repeatedly studied the above problems from the viewpoint of the composition and structure of ceramic resistors having an electric resistance of 10 ¹³ Ω-cm or less. For example, an insulator composed mainly of aluminum nitride formed by a chemical vapor synthesis method contains 0.005 to 30 atomic% of an element belonging to Group 4b of the periodic table, and the element is made of aluminum nitride crystal. By controlling the lattice constant of aluminum nitride in a specific range by forming a solid solution in the insulating layer, the volume resistivity of the insulating layer becomes 10 ¹³ Ω-
cm or less, and it was found that stable material properties could be obtained in a wide temperature range with a small change in temperature, leading to the present invention.

That is, the ceramic resistor of the present invention is a ceramic resistor mainly composed of an aluminum nitride crystal phase, wherein the element contains a Group 4b element of the periodic table in an amount of 0.005.
And the lattice constant in the crystal phase is a
It is a value shifted by 0.003-0.030 angstroms on the axis and 0.004-0.080 angstroms on the c-axis, and has a volume resistivity at 25 ° C. of 10 ¹³ Ω-cm or less. Is what you do.

Hereinafter, the present invention will be described in detail. The ceramic resistor according to the present invention is mainly composed of aluminum nitride.
It contains 5 to 30 atomic%. This periodic table 4
The group b element amount is an important element for imparting conductivity to aluminum nitride, and the amount of the element is 0.005.
If it is less than atomic%, the desired resistance cannot be obtained, and 30 atomic%
If it exceeds, another crystal phase is likely to be formed, making it difficult to control the resistance, and in the thin film, peeling and cracking are likely to occur. The elements of Group 4b of the periodic table are specifically C, Si, Ge, Sn, and Pb, and in particular, C and S
i is desirable in terms of film formability.

Further, this ceramic resistor is structurally
Although mainly composed of an aluminum nitride crystal, a part of the Group 4b element of the periodic table in the resistor is dissolved in the aluminum nitride crystal, but is not completely dissolved in the crystal. Depending on the group 4b element, a crystal phase such as a nitride of the group 4b group of the periodic table may be present in a proportion of 20% by weight or less. 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 Group 4b element of the periodic table. It is in the range of values shifted greatly or slightly, and the lattice constant (a
(Axis 3.120 angstroms, c-axis 4.994 angstroms).

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

The method for producing the ceramic resistor of the present invention is not particularly limited as long as the above-mentioned structure is satisfied. Preferably, specifically, physical vapor phase synthesis (PVD) such as sputtering and ion plating, plasma CVD, optical CVD, MO (M
et al.) Chemical vapor synthesis (CVD) such as CVD.
VD method is preferred. According to these film forming methods, the periodic table No. 4
A ceramic in which the lattice constant of an aluminum nitride crystal is changed by containing 0.01 to 30 atomic% of a Group 4b element of the periodic table employed in the present invention, which can synthesize aluminum nitride in which a group b element is excessively dissolved. A resistor can be obtained.

As a specific production method using Si as a Group 4b element of the periodic table and using a CVD method, N ₂ gas, NH ₃ gas, SiCl ₄ and AlC
l ₃ gas, and the flow ratio of these gases is N ₂ / AlC
l ₃ = 5-70, SiCl ₄ / NH ₃ = 0.001-
3. It can be manufactured by setting NH ₃ / AlCl ₃ = 0.1 to 10 and setting the film formation temperature 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, or a halide such as AlBr or an organic aluminum such as trimethylaluminum may be used instead of AlCl ₃ .

On the other hand, as the substrate on which the film is formed, any substrate can be used. Specifically, Al ₂ O ₃ , AlO
N, Si ₃ N ₄ , diamond, mullite, ZrO ₂ ,
W, Mo, Mo-Mn, TiN, SiC, WC, carbon and Si semiconductor materials (n-type or p-type) can also be cited. Among them, a sintered body mainly composed of aluminum nitride is most preferable in consideration of adhesion. desirable.

[0015]

[Action] 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 to replace aluminum or nitrogen with a group 4b element of the periodic table, it becomes a donor or an acceptor. It is considered that it contributes to the conductivity and increases 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 a change in the lattice constant. For example, the lattice constant of aluminum nitride containing no Group 4b element in 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 dissolves. Then, the lattice constant is calculated from these values by 0.003 to 0.03 on the a-axis.
If the value is shifted to a larger or smaller value by 0.004 to 0.080 angstroms on the c-axis at 0 Å, the volume resistivity can be controlled to 10 ¹³ Ω-cm or less.

Furthermore, the ceramic resistor of the present invention has a small change in resistance with respect to temperature. For example, in the case of general aluminum nitride, in the temperature range from room temperature (25 ° C.) to 300 ° C., 10 ¹⁶ Ω-cm to 10 ¹¹ Ω-cm. cm, whereas in the ceramic resistor of the present invention, for example, 1
It has the characteristic that it changes by less than three orders of magnitude from 0 ¹³ Ω-cm to 10 ¹¹ Ω-cm.
Even at a low temperature of 0 ° C., the volume resistivity having a small change rate is maintained.

Therefore, the present invention is particularly useful for an application such as an electrostatic chuck in a semiconductor manufacturing apparatus that requires a 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 was formed by placing the substrate in a furnace heated to 900 ° C. by an external heat method, nitrogen at 8 SLM, ammonia at 1 SLM, and 0 to 0.
5SLM SiCl4 gas is flowed and the pressure is 50 torr
And Further, the reaction was started by introducing aluminum chloride (AlCl ₃ ) at a flow rate of 0.3 SLM,
A film having a thickness of m was formed (Sample Nos. 1 to 9).

The obtained film is subjected to Si (S
The angle was corrected using RM640b) as a standard sample, and calculated by the peak top method. The measurement surface index is (100),
(002), (101), (102), (110),
(103), (112), and (004). Also,
The volume resistivity at −100 ° C., room temperature and 300 ° C. was measured and is shown in Table 1. In addition, No. 5 of -100 to 600
FIG. 1 shows the volume resistivity at ° C.

Example 2 An AlN film was formed on the surface of an aluminum nitride sintered body by a chemical vapor deposition method. The AlN film was formed by placing the substrate in a furnace heated to 900 ° C. by an external heat method, nitrogen at 8 SLM, ammonia at 1 SLM, and 0 to 0.
5 SLM CH ₄ , GeH ₄ , SnCl ₄ , Pb (CH
₃ ) The pressure was set to 50 torr by flowing ₄ gases. Further, the reaction was started by introducing aluminum chloride (AlCl ₃ ) at a flow rate of 0.3 SLM, and a film having a thickness of about 400 μm was formed (Sample Nos. 10 to 13). The lattice constant of the obtained film was calculated from the X-ray diffraction method in the same manner as in Example 1, and the volume resistivity at -100 ° C, room temperature and 300 ° C was measured. 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 also high insulating property of 9 × 10 ¹⁵ Ω-cm, but as the flow rate of SiCl ₄ was gradually increased, the amount of Si atoms in the film 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 to (002) by X-ray diffraction measurement. However, in the transmission electron microscope observation, a silicon nitride crystal phase is present, and the amount thereof is
l ₄ flow rate and correlation was observed.

With respect to the elements of Group 4b of the Periodic Table other than Si, the atomic weight and lattice constant of the Group 4b elements of the Periodic Table in aluminum nitride vary depending on the flow rate of the additive gas containing the Group 4b element of the Periodic Table. With a gradual increase in the flow rate of the additive gas containing a Group 4b element in the periodic table, the amount of the Group 4b element in the periodic table in the film increases, the lattice constant also gradually changes, and the volume resistivity decreases. . Note that the obtained aluminum nitride film was an AlN film oriented to (002) by X-ray diffraction measurement, and some had a 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 and lattice constant of Group 4b element of the periodic table in aluminum nitride. In addition, a resistor having a small temperature change can be obtained. Therefore, the properties of aluminum nitride,
For example, the resistance value can be changed without losing corrosion resistance.

[Brief description of the drawings]

FIG. FIG. 5 is a diagram showing a change in volume resistivity from −100 ° C. to 600 ° C. of FIG.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C04B 35/58 104H 104J (56) References JP-A-61-100901 (JP, A) JP-A-63-58706 (JP, A) JP-A-4-53202 (JP, A) JP-A-4-53203 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01C 7/00

Claims (2)

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