JP3261044B2 - Components for plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner wall material or a jig in a plasma processing apparatus, a semiconductor manufacturing or a plasma processing apparatus for a liquid crystal, which has a high corrosion resistance especially to a fluorine-based corrosive gas and a fluorine-based plasma. The present invention relates to a member for a plasma processing apparatus used as the above.

[0002]

2. Description of the Related Art In recent years, the use of plasma, such as a dry process for semiconductor manufacturing and plasma coating, has been rapidly advancing. As a plasma process in semiconductors, halogen-based corrosive gas such as fluorine is highly reactive,
It is used for vapor phase growth, etching and cleaning.

[0003] The members that come into contact with these corrosive gases are required to have high corrosion resistance. Conventionally, the members that come into contact with these plasmas other than the object to be processed are generally made of Si such as glass or quartz.
Materials containing O ₂ as a main component and corrosion-resistant metals such as stainless steel and Monel are often used.

[0004] In the production of semiconductors, a sintered body of alumina, sapphire, AlN, or a surface-coated body thereof by a CVD method or the like is used as a susceptor material for supporting and fixing a wafer because of its excellent corrosion resistance. ing. Further, a heater coated with graphite or boron nitride is also used.

[0005]

However, the glass and quartz used conventionally have insufficient corrosion resistance in plasma and are intensely depleted. In particular, when they come into contact with fluorine plasma, the contact surface is etched and the surface properties change. In the case of a member that requires light transmissivity, there have been problems such as that the surface gradually becomes cloudy and the light transmissivity decreases.

[0006] Further, even members made of metal such as stainless steel have insufficient corrosion resistance, so that corrosion causes a defective product, particularly in semiconductor manufacturing.

[0007] Alumina and AlN sintered bodies are more excellent in corrosion resistance to fluorine-based gas than the above materials, but when they come into contact with plasma at high temperature, the corrosion gradually progresses, and the surface of the sintered body crystallizes. There is a problem that particles are shed and cause particles to be generated.

[0008]

Means for Solving the Problems The present inventors have repeatedly studied methods for improving the corrosion resistance to a fluorine-based corrosive gas and plasma. The generation of fluoride having a melting point, in particular, a composite oxide of Group 3a metal of the periodic table and Al can be obtained at a low cost, and the fluoride forms a stable fluoride layer on the surface, thereby causing corrosion of members. It has been found that the corrosion resistance is suppressed, and the corrosion resistance superior to conventional alumina, glass, AlN, Si ₃ N _{4 and the} like can be realized.

That is, the member for a plasma processing apparatus of the present invention has been completed based on the above-mentioned findings, and has at least a direct contact with a fluorine-based corrosive gas or at least the corrosive gas or plasma in a corrosion-resistant member exposed to the plasma. Is formed of a complex oxide containing a Group 3a metal of the periodic table and Al, and the Group 3a metal of the periodic table is at least 30 atomic% of all metals, and Mo and W are 1% by weight or less of the total amount. In addition, when the thickness of the composite oxide is 10 μm or more, it is possible to provide a relatively inexpensive member having long-term resistance in a high-temperature, high-density fluorine-based corrosive atmosphere.

According to the present invention, by using a composite oxide material containing a Group 3a metal of the periodic table and Al as a member exposed to a fluorine-based gas and plasma, the material surface is stabilized by a reaction with fluorine. A strong fluoride layer is generated, and resistance to severe fluorine-based corrosive atmosphere is improved over a wide temperature range. Further, by suppressing the precipitation of elemental compounds such as Si, Ge, Mo, W, etc. which are easily volatilized by reacting with fluorine at the grain boundaries and by preventing their ubiquity, local deterioration of corrosion resistance and It is possible to prevent the generation of particles that fall due to this, and to further improve the corrosion resistance. These elements volatilize in the early stage of corrosion, but fluoride containing Group 3a remains on the material surface,
As a result, a fluoride layer rich in Group 3a element is formed, so that the progress of corrosion can be suppressed.

Furthermore, the composite oxide containing Group 3a metal of the periodic table and Al is more difficult to form by a thin film technique such as PVD and CVD than the metal oxide of Group 3a of the periodic table. Since it can be manufactured as a dense sintered body without stopping, it can be adapted to all shaped products.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A member for a plasma processing apparatus according to the present invention is a member exposed to a fluorine-based corrosive gas or fluorine-based plasma.
₆ , CF ₄ , CHF ₃ , ClF ₃ , HF, and the like. When a microwave, a high frequency, or the like is introduced into an atmosphere in which these gases are introduced, these gases are turned into plasma.

According to the present invention, the portion exposed to such a fluorine-based corrosive gas or its plasma is composed of a composite oxide containing at least a Group 3a metal of the periodic table and Al. Here, Sc, Y, La, Ce, and
Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y
b, Lu, etc., but especially Y, La,
Ce, Nd, and Dy are desirable in terms of cost.

[0014] The corrosion resistance of this composite oxide is 3a of the periodic table.
Group 3a metal of the periodic table is greatly affected by the amount of group metal,
It is important that the total content of the metal elements in the composite oxide be 30 atomic% or more, and it is particularly desirable that the content be 40 atomic% or more. This is because when the amount of Group 3a metal of the periodic table is less than 30 atomic%, the initial corrosion in the halogenated gas or its plasma is severe and a protective layer is gradually formed on the surface, but it takes a long time. Not practical.

The composite oxide may be a single crystal in addition to the above-mentioned glass and ceramic sintered body containing at least two kinds of metal elements. When the corrosion resistance of the grain boundary phase precipitated in the steel is remarkably inferior to that of the main crystal grains, the grain boundary phase is selectively corroded, causing degranulation and generation of particles. Therefore, it is important to suppress the content of Si, Ge, Mo, and W, which are easily corroded by fluorine, in the grain boundaries to 1% by weight or less in the total amount. This does not apply when these elements which are easily corroded by fluorine are dissolved in the main crystal grains and do not exist at the grain boundaries.

The composite oxide is desirably mainly composed of a crystalline material, particularly, YAG (3Y ₂ O ₃ .5Al).
Garnet type crystal such as ₂ O ₃ ), YAM (2Y ₂ O ₃ .A)
l ₂ O ₃₎ monoclinic type crystal such _{as, YAP (Y 2 O 3 ·} Al 2
O ₃ ) and the like mainly composed of perovskite crystals are desirable in that they have excellent corrosion resistance. Among these, a garnet-type crystal is most desirable because of its sinterability and low production cost.

The sintered body of the composite oxide may be prepared, for example, by mixing a mixture of a metal oxide belonging to Group 3a of the periodic table with Al ₂ O ₃ powder in an oxidizing atmosphere or a vacuum atmosphere at 1100 to 1900 ° C. It can be produced by firing.
As a firing method, a hot press method or the like is employed in addition to normal pressure firing.

Further, the members for the plasma processing apparatus of the present invention are not limited to such sintered bodies, but may be PVD,
It may be formed as a thin film on a predetermined substrate surface by a known thin film forming method such as a VD method. Further, a thin film obtained by applying and baking a liquid phase by a well-known sol-gel method may be used. Among these, a sintered body formed by molding and firing a powder is most desirable because of its excellent applicability to all members. Furthermore, this composite oxide is exposed to a halogen-based corrosive gas or its plasma. Although formed at the site, it is desirable that such a metal oxide has a thickness of at least 10 μm in order to impart excellent corrosion resistance. That is, if the thickness is less than 10 μm, excellent corrosion resistance cannot be expected.

[0019]

EXAMPLES Various materials shown in Table 1 were prepared using various oxide powders. In Table 1, sample no. Tables 1 and 2 are
A mixture of the rare earth oxide and SiO ₂ was melted at 2000 ° C., then rapidly cooled and vitrified. Sample N
o. 3-8 is obtained by firing at Y ₂ O ₃ and Al ₂ O ₃ with an oxidizing or vacuum atmosphere a green body comprising a mixture of 1600 to 1900 ° C.. Sample No. Reference numerals 9 and 10 denote 1400 molded articles made of a mixture of the rare earth oxide and Al ₂ O _{3 shown in} Table 1.
It was fired at １７1750 ° C. Sample No. 11
The sample No. was formed by sputtering using Sc ₂ O ₃ and Al ₂ O ₃ as targets. Reference numeral 12 is produced by a CVD method. In addition, all the sintered bodies were densified to a relative density of 95% or more.

Then, various materials shown in Table 1 were placed in an RIE plasma etching apparatus, and a mixed gas of CF ₄ and O ₂ (CF ₄ : O ₂ = 9: 1) and a mixed gas of Ar and SF ₆ were used. (Ar: SF ₆ = 2: 3) and a microwave were introduced to generate plasma. The material was kept in the plasma for a maximum of 3 hours, the weight loss of the material before and after the treatment was measured, and the thickness per minute (etching rate) was calculated from the value. The surface condition of the sample after the test was observed, and the results are shown in Table 1.

As comparative examples (sample Nos. 11 to 18), the same applies to conventional BN sintered bodies, quartz glass, Si ₃ N ₄ sintered bodies, Al ₂ O ₃ sintered bodies, and AlN sintered bodies. Was tested.

[0022]

[Table 1]

As shown in Table 1, all of the conventional materials have an etching rate of 70 ° / min or more, and the surface condition is very rough. In the case of the Si ₃ N ₄ sintered body, particles are generated on the surface. Was confirmed. Al ₂ O ₃ or Al
Numerous depressions due to etching were also observed in the sintered body of N.

For these comparative examples, sample Nos. 1 to 1
Each of the samples of the present invention No. 2 showed high corrosion resistance to fluorine-based plasma. In particular, when the sample was made of glass, the formation of dents on the surface was confirmed, but when the sample was made of a sintered body or a thin film, the surface condition was excellent. In addition, it was confirmed that a fluoride layer rich in a metal of Group 3a of the periodic table was formed on the surface of each of the samples of the present invention after the test.

[0025]

As described above in detail, according to the present invention, the member exposed to the fluorine-based corrosive gas and its plasma is made of a complex oxide of Group 3a metal of the periodic table and Al. In addition, a stable fluoride layer is formed on at least the material surface, and high corrosion resistance is achieved in a severe fluorine-based corrosive atmosphere. Moreover, since a sintered body can be easily manufactured,
It can be applied to all shapes.

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/00-35/22 C04B 35/42-35/50 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] A portion exposed to a fluorine-based corrosive gas or its plasma is made of a complex oxide containing a Group 3a metal and Al in the Periodic Table, and the Group 3a metal in the Periodic Table is 3% of all metals.
A member for a plasma processing apparatus, wherein 0 atomic% or more, Mo and W are 1% by weight or less of the total amount, and the thickness of the composite oxide is 10 μm or more.