JP2001044179A - Constituent member of chamber for manufacture of semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the constituent member of a chamber for manufacturing a semiconductor of superior plasma resistance and thermal conductivity. SOLUTION: This constituent member of a chamber is made of ceramics having 20 W/mK or over in heat conductivity where compounds containing crystalline rare earth elements are dispersed at a percentage of 10-60 volume % in the ceramic matrix, having at least one kind out of alumina and AlN for its main components. These compounds, containing the rare earth elements consist of an least one kind being selected from among a group of crystalline compounds between rare earth element-alumina composite oxides or rare earth element oxides and the matrix components. Furthermore, it is desirable that the porosity of the ceramics be 0.2% or lower, and that the ceramic matrix should have thermal conductivity of 30 W/mK or higher in single bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing a semiconductor device or a liquid crystal device, which comprises a CVD step using a fluorine-based and chlorine-based corrosive gas or a fluorine-based / chlorine-based plasma, a dry etching step, or an oxygen plasma. Semiconductor manufacturing including inner wall materials, microwave introduction windows, shower heads, focus rings, clamp rings, shield rings, etc. of equipment used in the ashing process for removing the resist by using it and the sputtering process exposed to ion bombardment The present invention relates to a chamber component for use.

[0002]

2. Description of the Related Art In recent years, the use of plasma such as a dry process and plasma coating used for forming a highly integrated circuit such as a semiconductor device has been rapidly progressing. As a plasma process in a semiconductor, a halogen-based corrosive gas such as a fluorine-based gas is used for vapor phase growth, etching and cleaning due to its high reactivity.

[0003] These members that come into contact with corrosive gas are required to have high corrosion resistance. Conventionally, members other than the processing object that come into contact with these plasmas 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 frequently used.

[0004] In the manufacture of semiconductors, as a susceptor material for supporting and fixing a wafer, an alumina sintered body, a sapphire, an AlN sintered body, a SiC sintered body, or those obtained by coating these with a surface by a CVD method or the like have excellent corrosion resistance. Used (Japanese Patent Publication No. 5-53872, JP-A-3-21
7016, JP-A-8-91932). Further, a heater coated with graphite or boron nitride is also used.

[0005]

However, members using corrosion-resistant metals, such as quartz glass and stainless steel, which have been conventionally used, have insufficient corrosion resistance in plasma and are intensely consumed. When contacted, the contact surface is etched to change the surface properties, and in the case of a quartz member that requires light transmissivity, there have been problems such as that the surface gradually becomes cloudy and the light transmissivity decreases. Also,
Even members made of a corrosion-resistant metal such as stainless steel have insufficient corrosion resistance, so that corrosion causes defective products especially in semiconductor manufacturing.

In order to solve the above problems, there have been proposed alumina sintered bodies, aluminum nitride sintered bodies, or those obtained by coating a surface of a carbon or silicon carbide sintered body with a ceramic film of silicon carbide or the like. However, although these materials have better corrosion resistance to halogen-based corrosive gases than the above quartz glass and corrosion-resistant metals, the corrosion gradually progresses again when contacted with plasma, and from the surface and grain boundaries of the ceramic sintered body. The halide evaporates and is consumed.

This is because the melting point of a compound of an aluminum component or a silicon component and a halogen-based gas generated in plasma is low. For this reason, materials with even higher corrosion resistance have been desired.

Further, in the dry etching process, not only the above-described corrosion resistance but also the generation of particles is a problem. This is because the generated particles cause disconnection or short circuit of the metal wiring on the semiconductor device, and cause deterioration of device characteristics.

[0009] The particles are generated when members such as an inner wall material and a clamp ring constituting the chamber and resists are corroded by a halogen-based corrosive gas or plasma. That is, the compound evaporated by the corrosion is repeatedly deposited on the inner wall of the chamber made of a particularly high corrosion-resistant material, and drops to become particles.

Therefore, in order to prevent the evaporated halide from depositing on the inner wall of the chamber as a deposit, the outer wall of the chamber is heated using a lamp or the like to evaporate and exhaust the halide. . Therefore, parts used in the chamber are required to have not only corrosion resistance but also high thermal conductivity.

On the other hand, the present inventors have proposed that a rare earth element-containing compound reacts with a halogen-based corrosive gas or its plasma as a material having high corrosion resistance to halogen-based corrosive gas and its plasma or ion bombardment. They have found that even if halides are formed, they have a high melting point, are stable and have excellent corrosion resistance, and have been proposed as members for plasma processing in semiconductor production. (JP-A-10-45467,
However, these compounds, in particular, Y which is considered to be practical as a ceramic material are disclosed.
_Since rare earth element-containing compounds such as ₂ O ₃ and YAG have a low thermal conductivity of 10 W / mK or less, even when externally heated to prevent the deposition of deposits on the inner wall of the chamber, the amount of heat is not uniformly distributed. Only a significant deposit-preventing effect was obtained.

[0012] It has also been proposed to improve the corrosion resistance and heat uniformity by forming a thin film made of a compound containing a rare earth element on the surface of a conventional high thermal conductive material such as AlN. Caused a difference such as peeling of the thin film during heating.

Accordingly, the present invention provides a semiconductor manufacturing method having high corrosion resistance to halogen-based corrosive gas and its plasma and ion bombardment, and having sufficient heat conductivity to prevent deposits from being deposited on the entire member by external heating. It is an object to provide a chamber component for use.

[0014]

Means for Solving the Problems The present inventors have provided a halogen-based corrosive gas and its corrosion resistance against plasma and ion bombardment, and have a sufficient thermal conductivity to prevent deposition of deposits over the entire member by external heating. As a result of repeated studies on members having alumina, alumina and AlN, in a ceramic matrix containing at least one of the main components, a crystalline rare earth element-containing compound, in particular, a rare earth element-alumina composite oxide, a rare earth element oxide, At least one selected from crystalline compounds with the matrix component
By using ceramics dispersed at a ratio of 60% by volume, it is possible to realize a member that exhibits high corrosion resistance, has a thermal conductivity of 20 W / mK or more, and can effectively prevent deposits from being deposited by heat treatment. Was found.

Further, since the corrosion resistance increases as the porosity of the ceramics decreases, the porosity is preferably suppressed to 0.2% or less.

It is effective that the ceramic matrix alone has a high thermal conductivity of 30 W / mK or more to maintain the thermal conductivity of the ceramic material.

[0017]

FIG. 1 is a schematic view showing the inside of a semiconductor manufacturing chamber. 1 is a chamber wall, 2 is a shower head, 3 is a clamp ring, 4 is a lower electrode, 5 is a wafer, and 6 is a high frequency coil. In addition, there are a parallel plate type RIE device and an ECR device using microwaves.

The halogen-based corrosive gas used in such an apparatus includes SF ₆ , CF ₄ , CHF ₃ , and ClF.
₃ , NF ₃ , C ₄ F ₈ , fluorinated gas such as HF, C
There are chlorine-based gases such as l ₂ , HCl, BCl ₃ and CCl ₄ , and bromine-based gases such as Br ₂ , HBr and BBr ₃ . Moreover, ashing for removing the resist or the like organic materials to burn organic matter by introducing O ₂ gas (as
ing). When microwaves or high frequencies are introduced in an atmosphere in which these halogen-based corrosive gases, oxygen, or the like is used, these gases are turned into plasma.

In order to further enhance the etching effect, plasma may be generated by introducing an inert gas such as Ar together with a halogen-based corrosive gas. In particular, the use of high-density plasma has increased the ratio of ion bombardment to etching.

The components of the semiconductor manufacturing chamber according to the present invention include components such as 1 to 4 shown in FIG.
Components that are exposed to halogen-based corrosive gas or its plasma and ion bombardment.In addition, in devices that generate plasma by means of focus rings, shield rings, anti-adhesion plates, and microwaves, components such as microwave windows are used. can give.

The present invention relates to a method for manufacturing a semiconductor manufacturing chamber which is exposed to the halogen-based corrosive gas or its plasma or ion bombardment in a high heat conductive ceramic matrix containing at least one of alumina and AlN as a main component. Is formed by dispersing 10 to 60% by volume of a crystalline rare earth element-containing compound, and particularly as a rare earth element-containing compound, a rare earth element-alumina composite oxide, a rare earth element oxide and the matrix component And a ceramic sintered body in which the crystalline compound is dispersed.

The ceramic matrix contains at least one of alumina and AlN, which exhibit relatively high corrosion resistance and high thermal conductivity, as main components. When the corrosion resistance of the ceramic matrix is low, the substance itself is intensely consumed, so that the deposits that cause the particles do not accumulate,
There is no need to prevent deposits by heating. Further, the thermal conductivity of the ceramic matrix is preferably 30 W / mK or more.

However, when alumina and AlN come into contact with corrosive gas or plasma, AlF ₃ , AlCl ₃
Generate Each melting point is AlF ₃ : 1040
° C, AlCl ₃ : 178 ° C, but AlF ₃ in particular has sublimability, and the sublimation of the reactant, the generation and adhesion to the surface of the member is remarkable, and the removal of AlF ₃ generated on the surface is very difficult. . When external heating is performed to prevent the deposition of the deposits, the reaction and sublimation with the halogen gas proceed, and the members are greatly consumed.

On the other hand, the rare earth element-containing compound reacts with a corrosive gas or plasma to form a stable compound having a high melting point (Y
F ₃ : 1152 ° C., YCl ₃ : 680 ° C.).
Accordingly, when a certain amount or more of the rare earth element-containing compound is dispersed in the above-described ceramic matrix, the ceramic matrix having high thermal conductivity is protected by the stable compound. Even if a reactant such as a resist deposited on the surface is evaporated by external heating, the compound obtained by the reaction between the rare earth element-containing compound and the corrosive gas or plasma is stable at a high melting point and does not evaporate or deteriorate.

Even if the corrosion progresses, since the crystalline rare earth element-containing compound is uniformly dispersed in the matrix, there is no decrease in the corrosion resistance due to the peeling and disappearance of the conventional thin film.

Further, by forming the rare earth element-containing compound from at least one selected from the group consisting of a rare earth element-alumina composite oxide and a crystalline compound of the rare earth element oxide and the matrix component, adhesion to the matrix can be improved. The effect is that the rare earth element-containing compound is uniformly dispersed in the ceramic sintered body, and the thermal conductivity of the ceramic matrix is maintained and sometimes improved.

Particularly, as the rare earth element-containing compound, at least one selected from the group consisting of a rare earth element-alumina composite oxide (eg, garnet type, perovskite type, melilite type) and a rare earth element-aluminum composite oxynitride is preferable.

It is common practice to add a rare earth element-containing compound as a sintering aid to the matrix component to form a grain boundary phase. The rare earth element-containing compound is only scattered at the grain boundaries with respect to the matrix phase which reacts and evaporates with the matrix phase, and a satisfactory effect on the improvement of corrosion resistance cannot be obtained.

From such a viewpoint, the content of the compound containing a crystalline rare earth element is set to 10 to 60% by volume, particularly 20 to 60% by volume, and more preferably 30 to 60% by volume, whereby 20 W
It is possible to greatly improve the corrosion resistance while maintaining a high thermal conductivity of / mK or more.

That is, when the content of the crystalline rare earth element-containing compound is less than 10% by volume, this compound exists mainly as a grain boundary phase of the matrix, and forms a protective film when it comes into contact with corrosive gas or plasma. The effect of improving the corrosion resistance cannot be expected without being formed. Further, only rare earth element-containing compounds that are scattered or localized with respect to the progress of corrosion of the matrix may remain and become particles.

The thermal conductivity of the rare earth element-containing compound itself is generally about 10 W / mK. When the content exceeds 60% by volume, the corrosion resistance is greatly increased because the rare earth element-containing compound has continuity in the ceramic matrix. Although it is improved, the overall thermal conductivity is reduced to not more than 20 W / mK, and effective prevention of deposit accumulation by heating cannot be expected.

In order to achieve both the improvement of corrosion resistance and the thermal conductivity of 20 W / mK or more, it is preferable that the content of the rare earth element-containing compound be changed depending on the type of ceramics and rare earth elements forming the matrix. For example,
In the case of rare earth elements with small ionic radii,
In the case of a rare earth element having a large ionic radius, it is desirable to increase the value slightly.

For elements having a small ionic radius, such as Y, Er, and Yb, the compound containing a rare earth element tends to have a garnet structure having a relatively high thermal conductivity.
%, More preferably 35 to 50% by volume. When AlN is used, the content is particularly preferably 30 to 60% by volume, and more preferably 40 to 55% by volume.

The rare earth element is replaced with La, C having a large ionic radius.
When e and Nd are used, the rare earth element-containing compound tends to have a perovskite structure having a relatively low thermal conductivity.
It is preferably 5 to 50% by volume, more preferably 35 to 40% by volume. When AlN is used, the content is particularly preferably 30 to 55% by volume, more preferably 35 to 45% by volume.

Further, the rare earth element-containing compound dispersed in the ceramic must be crystalline. This is because the thermal conductivity of a substance mainly depends on the propagation of phonons. When the crystallinity is reduced, the phonons are scattered at the defects and the thermal conductivity is reduced.

Further, by setting the porosity of the ceramic to 0.2% or less, particularly 0.1% or less, it is possible to further improve the corrosion resistance. That is,
If pores are present, abnormal discharge occurs at the edges of the pores, and corrosive gas stays inside the pores exposed on the surface, so that corrosion is likely to occur near the pores. If the porosity exceeds 0.2%, corrosion occurs. This is because the progress of the movement is easily accelerated.

The crystal phase in the ceramic sintered body was measured by X-ray diffraction, and the content of the rare earth element-containing compound was determined by X-ray diffraction measurement of a mixture of a ceramic matrix and a rare earth element-containing compound crystal. By preparing, the porosity can be obtained by the Archimedes method.

As shown in FIG. 1, in a portion exposed to a halogen-based corrosive gas or its plasma and ion sputtering,
By applying the sintered body constituted by the present invention, excellent corrosion resistance is exhibited, and heat is uniformly distributed throughout the member by heating, which is effective in preventing deposition of precipitates.

Such a semiconductor manufacturing chamber component can be manufactured, for example, by the following method.

A predetermined amount of one or more rare earth element oxides is added to and mixed with a ceramic raw material forming a ceramic matrix. At this time, a rare earth element oxide and alumina may be added, or a composite oxide of a rare earth element oxide such as YAG or YAM and alumina may be added.

Specifically, when the ceramic matrix is alumina, pure water or an organic solvent such as alcohol is used as the solvent. If necessary, paraffin wax, PVA, or the like is added as a binder. The mixed raw material is granulated and formed, and if necessary, raw processing and binder removal processing are performed. The molded body thus produced is usually fired in air at 1400 to 1800 ° C. in a non-oxidizing atmosphere depending on the nature of the rare earth element added.

In the case of AlN, an organic solvent such as alcohol and toluene is used as a solvent. A binder is added as necessary similarly to the case of alumina, and the mixed material is granulated,
Form and process. If binder removal is required, it is preferable to perform the treatment in a vacuum or in a nitrogen atmosphere. The molded body is fired at 1500 to 1900 ° C. in a nitrogen atmosphere. When baking at 1800 ° C. or higher, baking is preferably performed in a pressurized atmosphere to prevent the decomposition of AlN.

After the powder or the compact is fired under pressure, it may be processed into a predetermined shape. Alternatively, members can be formed by first preparing disassembled parts and bonding and joining them by an existing method. Further, the ceramic member thus obtained can be subjected to hot isostatic pressing to reduce the porosity and increase the density.

[0044]

EXAMPLES Using 99.9% pure alumina raw material, was 99.9% pure _{Y 2 O 3, Yb 2 O} 3, the CeO ₂ was added a predetermined amount. AlN has a purity of 99.9% and an oxygen content of 0.2.
% Of raw materials, and Y ₂ O ₃ , Y having a purity of 99.9%.
In addition to the predetermined amounts of b ₂ O ₃ and CeO ₂ , Al ₂ O ₃ (purity 99.9%) necessary for forming a crystal phase was added. For SiO ₂ , an amorphous raw material having a purity of 99.99% is used, and a predetermined amount of Y ₂ O ₃ , Yb ₂ O ₃ , CeO
₂ (and A required to form the rare earth element compound crystal phase
l ₂ O ₃ ) was added.

Paraffin wax was added as a binder to these raw material powders, mixed with a ball mill using IPA as a solvent, dried, granulated, and pressed.

The molded body is degreased in a vacuum, and alumina is 1500 to 1750 ° C. in the air (in nitrogen for a molded body with CeO ₂ added), and AlN is 170 g under nitrogen pressure.
0-1800 ° C., SiO ₂ is 1400-1 in a reducing atmosphere
It was fired at 500 ° C. to produce a ceramic having a porosity of 1% or less.

The crystal phase in the ceramic was identified by a powder X-ray diffraction method. The content of the rare earth element-containing compound crystal phase was determined from a calibration curve prepared by previously performing X-ray diffraction measurement on a mixture of a ceramic matrix and a rare earth element-containing compound crystal. Thermal conductivity was measured by a laser flash method, and porosity was calculated by an Archimedes method.

Regarding the etching rate, the etching rate when exposed to fluorine-based and chlorine-based plasma was evaluated. The evaluation method is as follows.
to prepare a test piece having a thickness of 1mm in mm square, the surface was obtained by mirror-processed sample, RIE fluoric using (reactive ion etching) apparatus CF _4, chlorine plasma at Cl ₂ An etching test was performed, and an etching rate was calculated from a change in weight before and after the test.

The presence or absence of particles is determined by processing each ceramic into a disk having a diameter of 8 inches and a thickness of 2 mm, polishing one side of the disk with a mirror surface, performing plasma etching, and then bringing an 8-inch Si virgin wafer into contact with the etched surface. Irregularities on the contact surface of the Si wafer were detected by laser scattering, and the number of particles of 0.3 μm or more was counted by a particle counter.

The parameters for the etching test were a gas flow rate of 100 sccm, an etching pressure of 5 Pa, an RF output of 1.0 W / cm ² , and an etching time of 5 hours.

[0051]

[Table 1]

From the results shown in Table 1, it was found that Sample No. 1 which is a ceramic material of the present invention was used. 2-7, 9-12, 14-18, 20
No. 23 to 23 each maintained a thermal conductivity of 20 W / mK or more and had high corrosion resistance of 5 nm / min or less to both fluorine-based and chlorine-based plasmas.

The sample No. 3-6, or 15-1
As for No. 7, when the porosity was 0.2% or less, high corrosion resistance of 3 nm / min or less was exhibited especially for both fluorine-based and chlorine-based.

Sample No. 1 in which the content of the rare earth element-containing compound was smaller than the predetermined amount. In Nos. 1 and 13, the ceramic matrix cannot be protected from corrosive plasma, and the corrosion is progressing. Conversely, for sample no. When the content of the rare earth element-containing compound exceeds 60% by volume as in 8, 19, the thermal conductivity of the ceramic matrix is remarkably impaired, and the thermal conductivity of the ceramic drops below 20 W / mK.

When the ceramic matrix itself is SiO _{2 having} low corrosion resistance, the effect of improving the corrosion resistance is poor even if a compound containing a rare earth element is added.
_Since the thermal conductivity of ₂ itself was less than 30 W / mK, the thermal conductivity of the produced rare earth element-containing oxide-dispersed ceramic did not become larger than 20 W / mK.

[0056]

As described above in detail, the semiconductor manufacturing chamber constituting member of the present invention is characterized in that a member exposed to a halogen-based corrosive gas or its plasma or ion bombardment is made of a crystalline rare earth element in a high heat conductive ceramic matrix. By dispersing a predetermined amount of the element-containing compound, it is possible to improve the corrosion resistance and maintain the thermal conductivity at a certain value or more, thereby enhancing the effect of preventing deposits from being deposited, and further, by reducing the porosity to 0.2% or less, the plasma is reduced. The corrosion resistance against

[Brief description of the drawings]

FIG. 1 is a schematic view of the inside of an etching apparatus which is an application example of a semiconductor manufacturing chamber constituent member of the present invention.

[Explanation of symbols]

 1. 1. chamber wall Shower head 3. Clamp ring 4. Lower electrode 5. Wafer 6. High frequency coil

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4G001 BA03 BA08 BA09 BA11 BA36 BB03 BB09 BB11 BB36 BD01 BD38 BE33 4G030 AA11 AA12 AA14 AA36 AA51 BA21 BA33 GA05 GA14 GA17 4G031 AA07 AA08 AA29 AA38 BA21 BA04 BA01 DA01BA04 DA01 DA04 DA05 DA11 DA16 DA17 DA18 DA20 DA23 DA26 DA29 DB26

Claims (4)

[Claims] 1. A thermal conductivity of 20 W / mK in which a crystalline rare earth element-containing compound is dispersed at a ratio of 10 to 60% by volume in a ceramic matrix containing at least one of alumina and AlN as a main component. A chamber component for semiconductor production, comprising the above ceramics. 2. The rare earth element-containing compound comprises at least one selected from the group consisting of a rare earth element-alumina composite oxide and a crystalline compound of a rare earth element oxide and the matrix component. 2. A member for forming a semiconductor manufacturing chamber according to claim 1. 3. The component of claim 1, wherein the ceramic has a porosity of 0.2% or less. 4. The ceramic matrix according to claim 1, wherein
4. The semiconductor manufacturing chamber component according to claim 1, wherein the component has a thermal conductivity of W / mK or more.