JP3025259B1 - Conductive ceramic pins - Google Patents

Abstract

【wrap up】 PROBLEM TO BE SOLVED: To reduce variation in resistivity and improve plasma resistance
To provide conductive ceramic pins that are also excellent. SOLUTION: A ceramic pin having conductivity is smelled.
Thus, the ceramic is an element belonging to Group 3A of the periodic table.
A compound containing at least one element thereof and TiO
_2-x(0 <x <2), and the compound and TiO_2-x
Of at least a part of the composite oxide
And the relative density of the ceramic is 95%
As described above, the resistivity is 10⁰-10¹³Ceramic in the range of Ωcm
Conductive ceramic pins that are made of

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic pin, and more particularly, to a conductive ceramic pin.

[0002]

2. Description of the Related Art In semiconductor manufacturing, the surface of a silicon wafer is charged with static electricity by plasma processing. In order to remove the static electricity, pins such as metal or ceramics having conductivity are brought into contact with the wafer surface to remove the static electricity, and then the silicon wafer is taken out. Among the pins, those made of metal are made of metal such as Al and SUS.

[0003] On the other hand, a pin made of conductive ceramics is a single piece of conductive ceramics such as SiC.
TiN, TiC, WC, WO ₂ , TiO _2-x (0 <x ≦
0.5). In addition, composite ceramics, in which the ceramics and insulating ceramics are combined using the conductivity of these ceramics,
For example _{Al 2 O 3 -SiC, Al 2} O 3 -TiO 2-x (0 <
x ≦ 0.5), AlN—TiN (TiC), Si ₃ N ₄ −
Some are made of composite ceramics such as TiC (TiN).

[0004]

However, the pin made of the above-mentioned metal has a problem that an arc discharge is liable to occur when the pin is made in contact with a silicon wafer because the resistivity is too low. Further, even a pin made of a single conductive ceramic has a problem that an arc discharge is also likely to occur similarly because the resistivity is too low.

On the other hand, the pin made of the composite ceramic can be adjusted to a target resistivity by changing the ratio between the conductive ceramic and the insulating ceramic, so that the resistivity is not too low. Since the composite ceramics consist only of sintering of particles with completely different compositions and greatly different resistivity, the resistivity of the pins is not uniform, and therefore, the variation of the resistivity of each pin is reduced. There is a problem that large and stable static elimination is difficult. In addition, since none of these composite ceramics has excellent plasma resistance, there is also a problem that the pins are short-lived because they are corroded by plasma irradiation.

The present invention has been made in view of the above-mentioned problems of the conductive ceramic pins, and has as its object to provide a conductive ceramic pin having a small variation in resistivity and excellent plasma resistance. It is in.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and have found that a compound containing at least one of the elements belonging to Group 3A of the periodic table and T
Based on the knowledge that if ceramics made of iO _2-x (0 <x <2) are used as conductive ceramic pins, it is possible to obtain conductive ceramic pins with small variation in resistivity and excellent plasma resistance. The invention has been completed.

That is, the present invention provides (1) a ceramic pin having conductivity, wherein the ceramic is made of
A compound containing at least one of the elements belonging to Group A and TiO _2-x (0 <x <2), and at least a part of the compound and TiO _2-x form a composite oxide And the relative density of the ceramic is 95% or more, and the resistivity is 10 ⁰ to 10 ¹³ Ω · cm.
(Claim 1) wherein the element belonging to Group 3A of the periodic table is at least one of Y, La and Yb. The conductive ceramic pin according to claim 1 (claim 2),
(3) The conductive ceramic pin according to claim 2, wherein the element belonging to the group 3A of the periodic table is Y (claim 3). A compound containing at least one of the elements belonging to Y
₂ O ₃ , and the composite oxide formed therefrom is Y ₂ T
iO _5-x (0 <x <5), Y ₂ Ti ₂ O _7-x (0 <x <7)
Or a mixture thereof.
The conductive ceramic pin according to any one of claims 1 to 3, wherein the relative density is 98% or more. Claim 5), and further,
(6) The conductive ceramic pin according to claim 1, 2, 3, 4, or 5, wherein the resistivity is 10 to 10 ¹¹ Ω · cm. I do. This will be described in more detail below.

As described above, as the ceramic pin having conductivity, the ceramic is made of the periodic table 3
A compound containing at least one of the elements belonging to Group A and TiO _2-x (0 <x <2), and at least a part of the compound and TiO _2-x form a composite oxide comprising a ceramic, and the relative density of the ceramics 95% or more, and the resistivity as a conductive ceramic pins to 10 ⁰ ~10 ¹³ Ω · cm range of ceramics (claim 1).

A ceramic pin having electrical conductivity is
Group 3A elemental compounds and TiO _2-xSera consisting of
The mix was made by setting the resistivity of this ceramic to Ti
O_2-xCan be easily controlled by changing the ratio of
And at the same time reduce the variation in resistivity.
The elemental compounds of group 3A of the periodic table have excellent corrosion resistance
In addition, plasma resistance can be extremely improved
According to

Here, the elements belonging to Group 3A of the periodic table are:
_{Y, L a, Yb, Sc} , Nd, Er, including but elements such as Sm, of which Y, La, Yb is preferable because the easily form a compound of the TiO _2-x (Claim 2). Although the details are unknown, the compounds of Y, La, and Yb can be mixed with TiO _2-x by Y ₂ TiO _5-x (0 <x <5),
Y ₂ Ti ₂ O _7-x (0 <x <7), La ₂ TiO _5-x (0 <
x <5), La ₂ Ti ₂ O _7-x (0 <x <7), La ₄ Ti
₉ O _24-x (0 <x <24), Yb ₂ TiO _5-x (0 <x <
5) It is considered that this is because a composite oxide such as Yb ₂ Ti ₂ O _7-x (0 <x <7) is easily formed. Among them, Y is more preferable because the compound is industrially available at low cost as a highly reactive starting material (claim 3). Among the compounds of Y, especially Y ₂ O ₃ is TiO
Combined with _2-x to form Y ₂ TiO _{5-x (} 0 <x <5) or Y ₂ Ti ₂ O
A composite oxide of _7-x (0 <x <7) and a mixture thereof are easily formed, so that they are more preferable (claim 4).

[0012] as a resistivity to the control, 10 ^0-1
A range of 0 ¹³ Ω · cm is preferable, and 10 to 10 ¹¹ Ω · cm.
It is still more preferable if it is in the range of (claim 6). The resistivity is 1
0 ⁰ Omega · to lower the current is too flows from cm occurred arc discharge current higher than conversely 10 ¹³ Omega · cm static elimination can not not flow.

Unless the variation in the resistivity is small, it is difficult to perform stable static elimination. If the variation in resistivity is small, a resistivity in a range almost matching the target resistivity can be obtained, and stable static elimination can be performed.However, if the variation increases, the resistivity may fall outside the targeted range of resistivity. , It is difficult to perform stable static elimination.
The pin of the present invention can reduce the variation in the resistivity, and thus can perform stable static elimination.

The variation in resistivity can be reduced by
Group 3A elemental compounds and TiO _2-xBetween and sintering
And at the same time, for example, Y_TwoTiO_5-x(0 <x <5), Y_Two
Ti_TwoO_7-x(0 <x <7), La_TwoTiO_5-x(0 <x <
5), La_TwoTi_TwoO_7-x(0 <x <7), La_FourTi₉O
_24-x(0 <x <24), Yb_TwoTiO_5-x(0 <x <
5), Yb_TwoTi_TwoO_7-xComplex oxidation such as (0 <x <7)
The pin composition becomes uniform and the resistivity increases.
Uniform, which is due to Al_TwoO_Three-TiO_2-x(0 <
x ≦ 0.5), much smaller than composite ceramics
It seems that it can be done. And the complex oxide is
It is more preferable that the core is a composite oxide, but some
Even if a complex oxide is formed, the effect
At least a part of the composite oxide
Should be formed.

The relative density of the ceramic is preferably as high as possible, but is preferably at least 95% or more.
It is even more preferable if it is 98% or more (claim 5). If the relative density is lower than 95%, the number of pores (pores) increases, and the variation in resistivity cannot be suppressed, and the plasma resistance also deteriorates.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention will be described. First, Y ₂ O ₃ , YN, L
_{a 2 O 3, Yb 2 O} 3, Sc 2 O 3, Nd 2 O 3, Er 2 O 3, S
Prepare a compound powder such as m ₂ O ₃ and add Ti
O ₂ powder is also prepared. The TiO ₂ powder may be a composite oxide containing TiO ₂ such as Y ₂ Ti ₂ O ₇ . The purity of these powders is preferably 98% or more for suppressing variation in resistivity, and more preferably 99% or more. The fineness of the powder is preferably 5 μm or less in average particle diameter for performing dense sintering, and more preferably 3 μm or less.

[0017] formulated prepared the Y ₂ O ₃ such as powder and a TiO ₂ powder in a predetermined ratio to resistivity is obtained as a target in the range of 10 ⁰ ~10 ¹³ Ω · cm, it organic solvent such as an alcohol Alternatively, water and the like are added and mixed by a ball mill or the like, and then dried, or a coprecipitate is separated from a solution of a salt, alkoxide, or the like having a predetermined composition, and then dried. To facilitate densification of this formulation, S
Sintering aids such as iO ₂ and MgO may be added. Regarding the form of the sintering aid, any form such as oxide powder, salts, and alkoxides may be used.

The prepared mixed powder is formed into a pin shape by a uniaxial press or a cold isostatic press (CIP). Since this must be depleted of oxygen from TiO _2, it is fired at a temperature of 1000 to 1900 ° C. in a reducing atmosphere or 100 ° C. beforehand in air or a reducing atmosphere.
After firing at a temperature of 0 to 1900 ° C.,
00-1900 temperature 1000 kgf / cm ² or more hot isostatic pressing at a pressure (HIP) process either relative density resistivity at 95% ℃ is 10 ⁰ ~10 ¹³ Ω · cm
Is sintered. This is processed into a pin to produce a ceramic pin.

The firing or HIP treatment time is not particularly limited, but may be about 2 to 4 hours. The firing temperature is 100
If the temperature is lower than 0 ° C., the densification becomes insufficient, the variation in resistivity is large, and if it exceeds 1900 ° C., the components may be decomposed. If the HIP processing temperature is lower than 800 ° C.
The effect of the treatment is small, and if it exceeds 1900 ° C., it may be decomposed as described above. HIP processing pressure is 1000kg
If it is lower than f / cm ^2, the effect of the HIP treatment is small.

Since the amount of oxygen deficiency varies depending on the reducing power of the reducing atmosphere, the stronger the reducing power, the more the oxygen bonded to Ti and also the oxygen bonded to the element of Group 3A of the periodic table. May also be lost,
With the reducing power of the carbon atmosphere which is usually adopted, Ti
Is only deficient in oxygen bonded to, and when the coefficient of Ti is m, the range is 0 <x <2m. That is, for example, in the case of Y ₂ TiO _{5 -x,} m = 1 and 0 <x <
In the case of Y ₂ Ti ₂ O _7-x or the like, m = 2 and 0 <x
<4. In the case of La ₄ Ti ₉ O _24-x , m = 9 and 0 <
x <18. The ceramic pin of the present invention shows an extremely stable resistivity in this range of oxygen deficiency.

When a ceramic pin having conductivity is manufactured by the above-described method, a conductive ceramic pin having small variation in resistivity and excellent plasma resistance can be obtained.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention and Comparative Examples.

(Examples 1 to 9) (1) Preparation of ceramic pins Element oxide powder of Group 3A of the periodic table shown in Table 1 having a purity of 98% or more and an average particle size of 3 μm, and a purity of 98% or more And a total of 200 g of TiO ₂ powder, Y ₂ Ti ₂ O ₇ powder or Y ₂ TiO ₅ powder having an average particle size of 2 μm in the ratio shown in Table 1.
Weigh the powder, put 200 g of each powder, ion-exchanged water and 250 g of φ10 mm iron cored nylon balls in a polyethylene pot mill, add 1 wt% of SiO ₂ or MgO as a sintering aid as needed, and add Mixed.

After the obtained slurry was dried under reduced pressure with a rotary evaporator, the obtained powder was subjected to a mesh pass with a # 100 nylon mesh. This powder was subjected to CIP molding at a pressure of 1200 kgf / cm ² to form φ10 × 15
It was molded to a size of 0 l. The obtained molded body is placed in the atmosphere for 1 hour.
After firing for 3 hours at a temperature of 500 ° C.,
HIP treatment was performed for 2 hours at a temperature of 400 ° C. and a pressure of 1800 kgf / cm ² , and the resultant was processed into φ2 × 100 l to produce 20 ceramic pins.

(2) Evaluation The bulk density of the obtained ceramic pins was determined by the Archimedes method, and the relative density was determined. Further, the resistivity of the obtained ceramic pin was measured by a four-terminal method. Furthermore, the obtained ceramic pins are brought into contact with a silicon wafer charged to 3000 V, and the presence or absence of arc discharge generated at that time is examined by direct observation of the contact portion, and the static electricity removal time of the charged static electricity is measured with a surface voltmeter. Examined. Furthermore, a ceramic pin was mounted on an actual machine, and a silicon wafer was treated with plasma (conditions: plasma type CF4 + O2 (10%), plasma output 1500 W), and the durability time until the pin was corroded and no longer used was examined. Table 1 shows the results.

Comparative Examples 1 to 7 In Comparative Example 1, the relative density was out of the range of the present invention by changing the firing temperature to 900 ° C., the HIP processing temperature to 700 ° C., and the HIP pressure to 500 kgf / cm ^2. Other than that, a ceramic pin was prepared and evaluated in the same manner as in the example. In Comparative Example 2, insulating ceramics having no conductivity were used as pins, and Comparative Examples 3 to
In No. 5, composite ceramics of insulating ceramics and conductive ceramics were used as pins, and in Comparative Examples 6 and 7, metal was used as pins and evaluated similarly. The results are also shown in Table 1.

As is apparent from Table 1, since the relative densities of all the examples are 98% or more, the resistivity is 10 to 10 ^11.
And no arc discharge occurred. And
Since all variations in the resistivity were small, the static elimination time was stable. Also, the durability by plasma was extremely high. This means that if the ceramic of the present invention is made of a conductive ceramic pin, the resistivity of the dispersion becomes almost close to the target resistivity and has a small variation, so that stable static elimination can be performed, and the plasma resistance is also extremely good. It is shown that it is.

On the other hand, in Comparative Example 1, although the ceramic of the present invention was used, the relative density was not within the range of the present invention, so that the variation in resistivity was large and the plasma resistance was extremely poor. . In Comparative Example 2,
Since the pins were made of insulating ceramics, static elimination could not be performed. Furthermore, in Comparative Example 3, although the resistivity was within the range of the present invention, the variation was much larger than in the example, and the plasma resistance was extremely poor.
Furthermore, in Comparative Examples 4 and 5, if the variation in the resistivity is small, it is possible to fall within the scope of the present invention. However, since the variation is large, some of the products fall outside the scope of the present invention. As a result, many arc discharges appeared. Further, in Comparative Examples 6 and 7, since the pins were made of metal, arc discharge was all generated.

[0029]

As described above, the ceramic pin having conductivity according to the present invention can be a conductive ceramic pin having small variation in resistivity and excellent plasma resistance. As a result, a pin having a stable static elimination characteristic and a long life can be suitably used for a silicon wafer take-out pin which is a semiconductor device-related component.

[Table 1]

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yukio Kishi 3-5-1 Meidori, Izumi-ku, Sendai, Miyagi Japan Nippon Cera Tech Co., Ltd. Examiner Yuichi Fukakusa (56) References JP-A-7-45315 ( JP, A) JP-A-3-5363 (JP, A) JP-A-5-330911 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/46 H01B 1/08 CA (STN) JICST file (JOIS) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. A ceramic pin having conductivity, wherein said ceramic is made of a compound containing at least one element selected from the group consisting of elements belonging to Group 3A of the periodic table.
_2-x (0 <x <2), and the compound and TiO _2-x
Is a ceramic in which at least a part thereof forms a composite oxide, and the relative density of the ceramic is 95%
As described above, a conductive ceramic pin characterized by being a ceramic having a resistivity in the range of 10 ⁰ to 10 ¹³ Ω · cm. 2. The element belonging to Group 3A of the periodic table,
2. The conductive ceramic pin according to claim 1, wherein the conductive ceramic pin is at least one of Y, La, and Yb. 3. An element belonging to Group 3A of the periodic table, wherein Y is Y.
The conductive ceramic pin according to claim 2, wherein: 4. A compound containing at least one of the elements belonging to Group 3A of the periodic table is Y ₂ O ₃ , and a composite oxide formed therefrom is Y ₂ TiO _5-x (0 <x <
_{5), Y 2 Ti 2 O} 7-x (0 <x <7) or a conductive ceramic pin according to claim 3, wherein the mixtures thereof. 5. The conductive ceramic pin according to claim 1, wherein said relative density is 98% or more. 6. The conductive ceramic pin according to claim 1, wherein the resistivity is 10 to 10 ¹¹ Ω · cm.