JP2003335583A - Joined body of alumina sintered bodies and their joining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable easy and secure joining of alumina sintered bodies which are used as materials for plasma devices for fabricating semiconductor- fabricating devices, by forming a joint layer between the alumina sintered bodies using yttrium aluminum garnet (YAG) either alone or in combination with a rare-earth oxide other than YAG to minimize effects of thermal and mechanical stresses on the joints and to increase bond strength between the alumina sintered bodies to an unprecedented level. <P>SOLUTION: In the joined body of the alumina sintered bodies, the alumina sintered bodies are mutually joined via the joint layer essentially comprising YAG. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joined body of alumina sintered bodies and a joining method thereof.

[0002]

2. Description of the Related Art In a plasma apparatus such as an etching apparatus or a CVD apparatus for manufacturing a semiconductor wafer, an alumina sintered body is often used for a susceptor, a high frequency transmission window, an electrostatic chuck, etc. Joining of alumina sintered bodies is often required in the fabrication of devices. For example, in order to insert an electrode into a susceptor, it is common practice to insert an electrode between two alumina plates and stack them, and then bond them with an adhesive.

At present, polyimide-based adhesives or silicon-based adhesives are used for joining alumina sintered bodies, but these polymer adhesives are vulnerable to halogen plasma such as fluorine-based adhesives. Deteriorates when exposed to plasma. Therefore, when joining the alumina sintered body using an adhesive, it is necessary to process the adhesive surface with high accuracy so that the adhesive is not exposed to the outside as much as possible, and the processing for that purpose requires a lot of labor. Was. However, even in such a case, in the plasma device which is repeatedly used, the joint portion of the alumina sintered body is first deteriorated, and a gap is formed there, so that the hermeticity of the device cannot be maintained. In addition to this, since alumina sintered bodies are hard and difficult to process, it has been attempted to join alumina sintered bodies of a predetermined shape to each other to form an alumina sintered body of a complicated shape. The plasma resistance of some parts was a problem.

When the alumina sintered bodies are joined together, a joining layer having different thermal expansion coefficients and different mechanical properties is formed at the joining portion. This bonding layer is easily deteriorated by thermal stress due to heating and cooling and various mechanical stresses, and even in such a case, the airtightness of the plasma device may be impaired. Therefore, in a plasma apparatus, it is desired to obtain an alumina sintered body which has a high bonding strength and is not deteriorated by thermal stress due to repeated heating and cooling, and the airtightness of the bonded portion is maintained for a long time. It was

[0005]

DISCLOSURE OF THE INVENTION In the present invention, an alumina sintered body is made of yttrium aluminum garnet (Y
AG) or this YAG and a small amount of yttria (Y
By using a rare earth oxide other than ₂ O ₃ ) for bonding, the bonding strength of the alumina sintered body can be increased, and the effects of thermal stress and mechanical stress at the bonded portion can be reduced, and plasma for semiconductor manufacturing can be obtained. It is intended to obtain a joined member of an alumina sintered body in which the plasma resistance of the joined portion of the alumina sintered body used in the apparatus is remarkably improved.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to alumina firing.
A joined body of alumina sintered bodies in which joined bodies are joined,
Alumina sintered body is yttrium aluminum gane
Bonded with a bonding layer containing YAG as a main component
A bonded body of alumina sintered bodies characterized by
1) The main component of the bonding layer of the bonded body is yttrium.
Aluminum Garnet (YAG), 10 more layers
Yttria (Y or less)_TwoO_Three) Other rare earth oxides
The alumina sintered body according to claim 1, comprising:
The joined body (claim 2) and the alumina sintered bodies are joined together.
At the time of joining, it must be
Rear (Y_TwoO_Three) Or yttrium aluminum
Garment (YAG) as a main component
Heating it in a reducing atmosphere at 1500 to 1900 ° C
Alumina sintered body for joining alumina sintered bodies together
(Claim 3), the bonding material is yttria
(Y_TwoO_Three) Or yttrium aluminum gar
Net (YAG) as the main component, and yttria (YAG)
_TwoO_Three10% by weight or less of rare earth oxides other than
The alumina sintered body according to claim 3, characterized in that
Joining method (Claim 4), joining alumina calcined bodies together
How to join alumina sinter by occasional sintering
This is the method of joining the alumina calcined bodies to be joined.
Trier (Y_TwoO_Three) Or yttrium aluminum
A joint material containing Mu Garnet (YAG) as the main component is sandwiched between
And heat it at 1500-1900 ° C in a reducing atmosphere
To bond the calcined alumina at the same time as sintering
Method of joining alumina sintered body (claim 5), the joining material
But yttria (Y_TwoO_Three) Or yttrium al
Main component is Minium Garnet (YAG), and it
Rear (Y_TwoO_Three10% by weight or less of rare earth oxides other than
A method for joining an alumina sintered body according to claim 5, which contains
(Claim 6) and the yttria (Y_TwoO_Three) Other than
The earth oxide is Er_TwoO_Three, Lu_TwoO_Three, Yb _TwoO_Three，
Tm_TwoO_Three, Ho_TwoO_ThreeAnd La_TwoO_ThreeOne of
7. One or more types according to claim 2, 4 or 6.
This is a method for joining alumina sintered bodies (claim 7).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, alumina sintered bodies are yttrium aluminum garnet (YAG).
It is a joined body of alumina sintered bodies joined by a joining layer containing as a main component. This bonded body, on the bonding surface of the alumina sintered body,
It is obtained by sandwiching YAG (Y ₃ Al ₅ O ₁₂ ) and heating it in a reducing atmosphere while pressing both sides of it.
In order to sandwich YAG on the joint surface of the alumina sintered body, a method of forming YAG powder slurry and applying it to the joint surface is generally used, but YAG solid may be sandwiched on the joint surface of the alumina sintered body. Further, a YAG paste may be prepared and applied. When the YAG slurry is applied, its thickness is not less than the roughness of the joint surface of the alumina sintered body, for example, 10 to 3
Apply to a thickness of 00 μm. After that, press this to dry it while adhering closely to remove the moisture on the joint surface, and in this state, heat it in a hydrogen atmosphere, a nitrogen atmosphere, or another reducing atmosphere so that the base material alumina on the joint surface is bonded. Y
It diffuses into the AG and performs coupling. The YAG formed in the bonding layer forms a dense and hard bonding state because a part of the base alumina on both sides is diffused, and
Since the difference between the coefficient of thermal expansion of YAG and the coefficient of thermal expansion of the alumina sintered body is small, it is possible to extend the life by heat cycle.

For joining alumina sintered bodies with YAG layers
Instead of sandwiching YAG at the joint as described above,
Rear (Y_TwoO_ThreeThe slurry of 1) may be used. In addition, this
In the case of, it is not changed that the main component of the bonding layer is YAG.
No, but outside of this, YAM (Y _FourAl₅O₉), YAP
(YALO_Three) May be formed.

When forming the YAG coupling layer, Y
When 10% by weight or less of a rare earth oxide other than yttria is added together with AG, the melting point of YAG is lowered and its fluidity is improved, and the adhesion at the joint between the base alumina and the YAG layer is further improved. Further, the temperature of heating in a reducing atmosphere at the time of joining can be lowered by adding a rare earth oxide. Furthermore, when a rare earth oxide other than yttria is added in an amount of 10 wt% or less, the linear expansion coefficient of YAG in the bonding layer becomes closer to that of alumina, and the alumina and YA
Linear thermal expansion difference with G 1.0 × 10 ⁻⁶ K / ℃ (Temperature range 0 to 1000
℃) can be further shortened. Rare earth oxides other than yttria used here are Er ₂ O ₃ and Lu.
₂ O ₃ , Yb ₂ O ₃ , Tm ₂ O ₃ , Ho ₂ O ₃ and La
₂ O ₃ , which is one or more, for example, La ₂
With O ₃ , the effect is confirmed even when added in a small amount of 0.01% by weight. If this rare earth oxide is added in an amount exceeding 10% by weight, the mechanical strength of YAG as a bonding layer may be impaired, so the upper limit of the addition amount is 10% by weight. The preferable addition amount of the rare earth oxide other than yttria is 0.5 to
It is 5% by weight.

Further, in the present invention, as the members to be joined,
In addition to the alumina sintered body, it is possible to use a calcined alumina body. That is, YAG or yttria is sandwiched between the joint surfaces of the calcined alumina body in the same manner as above, and the calcined alumina body is made into a sintered body by heating it in a non-oxidizing atmosphere, and the sintered body Is a combined body of. Furthermore, it is also the same that a rare earth oxide other than yttria can be included.

According to the present invention, the alumina sintered body or the alumina calcined body is joined to the alumina sintered body by sandwiching YAG or yttria on the joining surface of alumina and further containing a substance containing a rare earth oxide other than yttria. It is performed by heating in a reducing atmosphere while pressing each other, and the pressing here is sufficient to press the bonded body so that the bonded state is maintained, for example, about 100 g / cm ² is sufficient.

As described above, Y is formed on the bonding surface of the alumina sintered body.
YAM (Y ₄ Al ₅ O containing the AG layer and the YAG layer as main components
₉ ) A layer containing YAP (YAlO ₃ ) or a layer further containing a rare earth oxide other than yttria is formed. Since the coefficient of thermal expansion of the bonding layer is similar to that of the alumina sintered body of the base material, it is possible to provide an excellent bonded member of the alumina sintered body in which the occurrence of cracks due to thermal history is avoided. Further, in the case of conventional bonding with a polymer adhesive, the bonding surface has to be processed with high precision so that the adhesive is not exposed to the outside in order to prevent the adhesive from being deteriorated by plasma. According to the present invention, since the YAG of the joint has plasma resistance, it is not necessary to particularly improve the machining accuracy of the joint surface, and it is possible to reduce the machining cost in that respect.

[0013]

Example 1 YAG (Y ₃ Al ₅ O ₁₂ ) powder, La ₂ O ₃ powder, pure water, dispersant, and alumina balls were put in a pot, which was rotated for 12 hours to make a YAG slurry. Prepared. This slurry is applied to the joint surfaces of two plate-shaped alumina sintered bodies, the alumina sintered bodies are joined together, a load of 200 g / cm ² is applied to the joined bodies, and the two are pressure-bonded to each other for 24 hours at 45 ° C. After that, the water on the joint surface was dried. Then, this joined body was fired in an electric furnace in a hydrogen atmosphere to form a joined body of alumina sintered bodies.

This bonded body was scanned with a scanning electron microscope (SEM).
It was as shown in FIG. As can be seen from FIG. 1, the alumina of the base alumina sintered body is YA.
The base alumina sintered bodies are firmly bonded to each other by being diffused in the bonding layer made of G and La ₂ O ₃ . A heat cycle test was performed in order to confirm the joining state of the alumina sintered body, and the occurrence of cracks at the joining portion was examined. In addition, the same sample was also examined for fluorine plasma properties. The results are shown in Table 1.

(Example 2) A bonded body of alumina sintered bodies was formed in the same manner as in Example 1. However, in Example 2,
As a rare earth oxide other than yttria, Er ₂ O ₃ was added in the same amount instead of La ₂ O ₃ . Tests were performed on these alumina sintered bodies in the same manner as in Example 1 to examine the bonding state. The results are shown in Table 1.

Example 3 Yttria (Y ₂ O ₃ ) powder, Lu ₂ O ₃ powder, pure water, dispersant, and alumina balls were put in a pot and the pot was rotated for 12 hours to prepare a yttria slurry. This slurry is applied to the joint surfaces of two plate-shaped alumina sintered bodies, the alumina sintered bodies are joined together, and a pressure of 200 g / cm ² is applied to the joined body to press-bond it.
The joint surface was allowed to dry for 4 hours at 45 ° C. Then, this joined body was fired at 1600 ° C. in a hydrogen atmosphere to form a joined body of alumina sintered bodies.

When the bonding layer of this bonded body was examined by SEM, the yttria at the bonded portion and the alumina sintered body were firmly bonded. In order to confirm the bonding state of this alumina sintered body, the same heat cycle test as in Example 1 was performed to examine the crack generation state at the bonding portion. In addition, the same sample was also examined for fluorine plasma properties. The results are shown in Table 1.

(Example 4) The same YAG as in Example 1 was used to prepare a slurry. In Example 4, as the rare earth oxide other than yttria, the same amount of Tm ₂ O ₃ was added instead of La ₂ O ₃ . . Further, an alumina calcined body was used as the bonding base material instead of the alumina sintered body. That is, the above-mentioned slurry was applied to each joint surface of two plate-shaped alumina calcined bodies to bond the alumina calcined bodies together, and a pressure of 200 g / cm ² was applied to the jointed body for pressure bonding for 24 hours 45 The joint surface was left to stand to be dried at ℃. After that, this bonded body is placed in a hydrogen atmosphere for 1
It was fired at 700 ° C. in an electric furnace to form a joined body of alumina sintered bodies. In order to confirm the bonding state of this alumina sintered body, the same heat cycle test as in Example 1 was performed to examine the crack generation state at the bonding portion. The same sample was also examined for fluorine-based plasma properties, and the results are shown in Table 1.

Example 5 A joined body of alumina sintered bodies was formed in the same manner as in Example 1. However, in Example 5,
As a rare earth oxide other than yttria, the same amount of Ho ₂ O ₃ was added instead of La ₂ O ₃ . The heating of the joining member was performed at 1800 ° C. in the atmosphere. A test was performed on this alumina sintered body in the same manner as in Example 1, the bonding state was examined, and the results are shown in Table 1.

Example 6 A joined body of alumina sintered bodies was formed in the same manner as in Example 1. However, in Example 6, YAG alone was used as the bonding member, and no rare earth oxide other than yttria was added. The heating of the joining member was performed at 1700 ° C. in a hydrogen atmosphere. When this joined body was observed with a scanning electron microscope (SEM), it was as shown in FIG. A heat cycle test was performed in order to confirm the joining state of the alumina sintered body, and the occurrence of cracks at the joining portion was examined. The same sample was also examined for fluorine-based plasma properties, and the results are shown in Table 1.

(Comparative Example 1) Alumina sintered bodies were bonded with a polyimide adhesive. Tests were performed on these alumina sintered bodies in the same manner as in Example 1 to examine the bonding state. The results of the tests of the above Examples and Comparative Examples are summarized in Table 1 below.

[0022]

[Table 1]

As is clear from Table 1, in all of the joined bodies of the alumina sintered bodies according to the present invention (Examples 1 to 5), cracks did not occur even after 500 heat cycles, and in Example 6, 170 Cracks do not occur even after repeated heat cycles, and since the yttrium compound is used, plasma resistance is also good. As a result, the joints that have undergone thermal history have a good joint condition, and no gaps are created here. Even when this is used in a plasma device, it is possible to maintain a high degree of airtightness over a long period of time. Is.

[0024]

As described above, according to the present invention, YAG or YAG and a rare earth oxide other than yttria are sandwiched between alumina sintered bodies and heated, whereby the alumina sintered bodies are firmly bonded and Since the joining member is made of YAG, which is a yttria compound having a similar coefficient of thermal expansion, no gap is created at the joint portion due to cracks or the like due to the difference in coefficient of thermal expansion. Further, in the present invention,
Since the joining portion is mainly composed of YAG and thus has excellent plasma resistance, the present invention can be stably used for various members in a plasma device.

[Brief description of drawings]

FIG. 1 is an electron micrograph of a metal structure of a joint portion of an alumina sintered body according to an embodiment of the present invention.

FIG. 2 is an electron micrograph of a metal structure of a joint portion of an alumina sintered body according to another embodiment of the present invention.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruo Murayama             No. 1 Nanto, Ogakie Town, Kariya City, Aichi Prefecture             Lamix Co., Ltd. Kariya factory (72) Inventor Keiji Morita             No. 1 Nanto, Ogakie Town, Kariya City, Aichi Prefecture             Lamix Co., Ltd. Kariya factory F term (reference) 4G026 BA03 BB03 BF04 BF44 BF45                       BG04 BG05 BG06 BG28 BG30                       BH01

Claims (7)

[Claims] 1. A joined body of alumina sintered bodies obtained by joining alumina sintered bodies together, wherein the alumina sintered bodies are joined by a joining layer containing yttrium-aluminum-garnet (YAG) as a main component. A joined body of alumina sintered bodies characterized by the above. 2. The joint layer of the joint body is mainly composed of yttrium aluminum garnet (YAG) and further contains 10 wt% or less of rare earth oxide other than yttria (Y ₂ O ₃ ). The joined body of the alumina sintered body according to claim 1. 3. When joining alumina sintered bodies together,
Between the alumina sintered bodies to be joined, yttria (Y
₂ O ₃ ) or yttrium-aluminum-garnet (YAG) as a main component is sandwiched and heated at 1500 to 1900 ° C. in a reducing atmosphere to bond the alumina sintered bodies together. Joining method. 4. The bonding material is yttria (Y ₂ O ₃ ).
Or yttrium aluminum garnet (YA
4. The method for joining an alumina sintered body according to claim 3, wherein the main component is G) and a rare earth oxide other than yttria (Y ₂ O ₃ ) is contained in an amount of 10% by weight or less. 5. A method for joining alumina sintered bodies by simultaneously sintering the alumina calcined bodies, wherein yttria (Y ₂ O ₃ ) or A method for bonding an alumina sintered body, in which a bonding material containing yttrium aluminum garnet (YAG) as a main component is sandwiched and heated at 1500 to 1900 ° C. in a reducing atmosphere to simultaneously bond the calcined alumina body. . 6. The bonding material is yttria (Y ₂ O ₃ ).
Or yttrium aluminum garnet (YA
The method for joining alumina sintered bodies according to claim 5, wherein G) is a main component, and a rare earth oxide other than yttria (Y ₂ O ₃ ) is contained in an amount of 10% by weight or less. 7. The rare earth oxide other than yttria (Y ₂ O ₃ ) is Er ₂ O ₃ , Lu ₂ O ₃ , Yb ₂ O ₃ , T.
The method for joining alumina sintered bodies according to any one of claims 2, 4 and 6, which is at least one selected from m ₂ O ₃ , Ho ₂ O ₃ and La ₂ O ₃ .