JP2010006641A - Corrosion resistant member and treatment device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the strength of an alumina base material because an Al component is diffused from an alumina base material to an yttria film when an intermediate layer is formed.
SOLUTION: A corrosion resistant member 1 in which a corrosion resistant film 2 mainly composed of yttrium oxide is provided on a substrate 4 mainly composed of alumina via an intermediate layer 3, the intermediate layer 3 being formed on the substrate side. The first intermediate layer 3a mainly composed of Y ₃ Al ₅ O ₁₂ and the second intermediate layer 3b mainly composed of Y ₄ Al ₂ O ₉ are provided on the corrosion-resistant film 2 side.
[Selection] Figure 1

Description

  The present invention is used for a processing apparatus such as a semiconductor manufacturing apparatus, a liquid crystal manufacturing apparatus or the like (including various etching apparatuses, ALD apparatuses, CVD apparatuses, PVD apparatuses, measuring apparatuses, vacuum apparatuses, etc.), and particularly corrosive. The present invention relates to a corrosion-resistant member that can be suitably used for components exposed to gas or plasma, and further relates to a processing apparatus using the same.

  In recent years, corrosion-resistant members such as an inner wall material of a vacuum chamber, a microwave introduction window, a focus ring, and a susceptor are exposed to plasma in an atmosphere of a halogen-based corrosive gas such as fluorine or chlorine. Such a corrosion-resistant member has been proposed and put into practical use by being formed of a ceramic having higher corrosion resistance instead of a conventional metal. Ceramics often have a high melting point of a reaction product with a corrosive gas component, and are difficult to evaporate even under high-temperature plasma. For this reason, the progress of corrosion is delayed, and as a result, excellent corrosion resistance is exhibited.

  However, when ceramics are used for corrosion resistant members for various semiconductor manufacturing apparatuses, it is difficult to uniformly fire the whole when the member shape is thick. For this reason, a difference arises in the density difference, the distribution of impurity components, and the like between the surface and the inside of the corrosion-resistant member. This leads to a decrease in corrosion resistance and mechanical properties.

  Recently, attempts have been made to form a ceramic corrosion resistant film on the surface of the substrate. Since the corrosion-resistant film is thin, it can be fired more uniformly. For this reason, it is possible to obtain a member for a semiconductor manufacturing apparatus that is less likely to cause a difference in corrosion resistance and mechanical properties between the surface and the inside of the corrosion-resistant film, and that has good characteristics.

For example, in Patent Document 1, an yttria film is formed on an alumina base material by a thermal spraying method, and this is heat-treated at 1300 to 1800 ° C., and an intermediate layer composed of a reaction product of yttria and alumina between the yttria film and the alumina base material. Has been proposed to form.
Japanese Patent Laid-Open No. 2002-1865

  However, when the Al component of the alumina base material is reacted with the Y component of the yttria film by heat treatment at a high temperature to form an intermediate layer made of the reaction product, the mechanical strength of alumina as the base material may be reduced. .

  Also, the film formed by the surface spraying method is not densified, and there are still gaps between the laminated sprayed particles, and corrosive gas enters through these gaps to corrode the intermediate layer and the substrate. There are things to do.

  Furthermore, since the yttria film formed by the thermal spraying method before the heat treatment is not in homogeneous contact with the substrate surface at the interface with the alumina substrate, it is difficult to form a homogeneous intermediate layer after the heat treatment.

  An object of the present invention is to provide a corrosion-resistant member having a uniform and good intermediate layer and a processing apparatus using the same, which can densify the corrosion-resistant film without impairing the mechanical properties of the substrate.

The corrosion-resistant member of the present invention is a corrosion-resistant member in which a corrosion-resistant film mainly composed of yttrium oxide is provided on a substrate mainly composed of alumina via an intermediate layer, and the intermediate layer is formed on the substrate side. And having a first intermediate layer mainly composed of Y ₃ Al ₅ O ₁₂ and a second intermediate layer mainly composed of Y ₄ Al ₂ O ₉ on the corrosion-resistant film side.

  Further, the processing apparatus of the present invention includes a container whose inside is exposed to a gas or plasma environment thereof, and the corrosion-resistant member is disposed on at least a surface of the component in the container exposed to the gas or plasma thereof. It is used.

  According to the corrosion-resistant member of the present invention, it is possible to suppress the diffusion of the Al component from the alumina base material to the film side as much as possible, and to suppress the deterioration of the mechanical properties of the base material.

  Moreover, according to the processing apparatus of this invention, compared with the case where the conventional components are used, the lifetime of components becomes long and can also provide a highly reliable processing apparatus.

  Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as the present embodiment) will be described.

As shown in FIG. 1, the corrosion-resistant member 1 of this embodiment includes a corrosion-resistant film 2 mainly composed of yttrium oxide on a substrate 4 mainly composed of alumina (alumina in the substrate 4 is 50% by mass or more). (Yttrium oxide in the corrosion-resistant film 2 is 50 mass% or more) is provided via the intermediate layer 3. Here, the intermediate layer 3 has a first intermediate layer 3a (YAG in the intermediate layer 3a is 50% by mass or more) mainly composed of Y ₃ Al ₅ O ₁₂ (hereinafter referred to as YAG) on the base 4 side, A second intermediate layer 3b (YAM in the intermediate layer 3b is 50% by mass or more) mainly composed of Y ₄ Al ₂ O ₉ (hereinafter referred to as YAM) is provided on the corrosion-resistant film 2 side.

  With such a structure, the conventional corrosion-resistant film (corrosion-resistant film 2 is formed on substrate 4 by thermal spraying, and this is heat-treated at a high temperature of 1300 to 1800 ° C. so that yttria and alumina are interposed between corrosion-resistant film 2 and substrate 4. It is possible to prevent the Al component in the alumina that is the base material 4 from diffusing to the corrosion resistant film 2 side and the mechanical properties of the base material 4 from being deteriorated as compared with the corrosion resistant film forming the reaction product of It becomes possible.

  In the present embodiment, the reason why the Al component of the base material 4 does not diffuse to the corrosion-resistant film 2 side is to form a YAG layer synthesized in advance on the base material 4 side as the intermediate layer 3. Also, when the intermediate layer 3 is formed and then heat treated to join the base material 4 and the first intermediate layer 3a made of YAG, the Al component hardly diffuses into the first intermediate layer 3a made of YAG. Further, the mechanical properties of the substrate 4 are not deteriorated. In the present invention, since the second intermediate layer 3b made of YAM synthesized in advance is also formed on the corrosion resistant film 2 side, there is almost no diffusion of the Al component from the second intermediate layer 3b to the corrosion resistant film 2. In addition, the corrosion resistant film 2 is not a conventional thermal spraying method, but a method in which a slurry containing yttria particles is coated and then heat treated to form a dense film. Become.

  Moreover, the corrosion-resistant member 1 of this embodiment is characterized in that the average void ratio of the corrosion-resistant film 2 and the intermediate layer 3 is 1% or less. If the average void ratio of the corrosion-resistant film 2 and the intermediate layer 3 is 1% or less, when the corrosion-resistant member 1 of this embodiment is used as, for example, an inner wall member in a chamber of a semiconductor manufacturing apparatus, halogen supplied into the apparatus The system corrosive gas passes through the voids on the film surface and enters the member, so that the corrosion resistant film 2, the intermediate layer 3, or the base material 4 is hardly corroded.

  In addition, the average void ratio is, for example, a metal microscope or SEM in which the surface of the corrosion-resistant film 2 and the intermediate layer 3 whose surfaces are precisely ground are adjusted to an arbitrary magnification so that a range of 100 μm × 100 μm can be observed. It is possible to calculate by taking a photograph or an image as described above and analyzing the photograph or image with an image analysis apparatus. As an image analysis apparatus, for example, LUZEX-FS manufactured by Nireco Corporation may be used.

  Furthermore, the corrosion resistant member 1 of the present invention is characterized in that the arithmetic average height (Ra) of the surface of the corrosion resistant film 2 is 1 μm or less. The corrosion-resistant film 2 of the corrosion-resistant member 1 of the present invention is a dense film, and the film surface is a smooth surface as compared with the conventional thermal spraying method. If the arithmetic average height (Ra) is 1 μm or less, the contact area with the halogen-based corrosive gas can be reduced. Therefore, the progress of corrosion is slowed and the life of the corrosion-resistant film 2 can be extended.

  The arithmetic average height (Ra) of the surface is based on JIS B 0601-2001, using a contact or non-contact surface roughness meter, for example, a cutoff value (reference length) of 0.8 mm, evaluation It is possible to measure under the condition setting according to the JIS standard (JIS B 0601 3, JIS B 0633 4, JIS B 0031 appendices G and F) having a length of 4 mm.

Further, as shown in FIG. 2, the corrosion-resistant member 1 of another embodiment is characterized by having a third intermediate layer 5 made of YAlO ₃ between the first intermediate layer 3a and the second intermediate layer 3b. . The contact surfaces of YAG of the first intermediate layer 3a and YAM of the second intermediate layer 3b are bonded to each other by a low melting point glass component contained in a trace amount in YAG and YAM when heat-treated at a relatively low temperature. However, when heat treatment is performed at a high temperature, it is possible to form the third intermediate layer 5 made of YAlO ₃ (hereinafter referred to as YAP) which is a reaction layer. It becomes possible to increase the bonding strength of the two intermediate layers 3b.

  In addition, about the 3rd intermediate | middle layer 5, the cross section of the corrosion-resistant member 1 of this embodiment can be analyzed with an X-ray-diffraction apparatus, and presence of a YAP layer can be confirmed from the chart.

  Next, the manufacturing method of the corrosion-resistant member 1 of this embodiment is demonstrated. First, about the base material 4, after purchasing the alumina primary raw material whose commercially available purity is 99 mass% or more and whose average particle diameter is 0.5-5 micrometers and adding a binder and a solvent to this, it is made a slurry, and is sprayed. Spray granulation with a drier to produce an alumina secondary material. After granulation, the alumina secondary raw material is molded at a molding pressure of 50 to 150 MPa by a wet isostatic press molding method (rubber press method), and this is processed into a predetermined size by cutting to obtain a molded body. And it can obtain by baking the molded object after a cutting process by the baking temperature of 1500-1700 degreeC of maximum temperature in the baking furnace of an atmospheric atmosphere.

  Next, for the corrosion resistant film of the corrosion resistant member 1 of the present embodiment, first, a YAG raw material having a purity of 99% or higher, a YAM raw material, and a commercially available purity of 99.5% by weight or higher, which were synthesized in advance by adjusting the ratio of alumina and yttria. The yttria primary raw material is prepared. Thereafter, a binder and an aqueous or organic solvent are added to each raw material to form a slurry. This is applied to the surface of the substrate 4 by a coating method such as dip coating, bar coating, or spray coating. And after drying at 50-200 degreeC, it can manufacture by heat-processing in the furnace using the baking furnace of an atmospheric condition. At this time, yttria, YAG, and YAM are prepared by pulverizing them to an average particle size of 1 μm or less, more preferably 0.8 μm or less. More preferably, the average particle size is 0.5 μm or less. When the finely pulverized raw material is used, the heat treatment temperature can be made lower than the conventional 1300 ° C., and 1100 ° C. or higher and 1300 ° C. It becomes possible to make it dense at a temperature below. Further, yttria sol can be used as a raw material for the corrosion-resistant film 2.

  The average particle size of the coarse particles and fine particles is measured by using a laser diffraction scattering method (Nikkiso Co., Ltd.) after adding the coarse particles and fine particles to the dispersion medium and dispersing them in the dispersion medium using a disperser. Measurement can be performed with a Microtrac).

  Further, as another manufacturing method of the present embodiment, when YAG and YAM raw materials and yttria raw materials are overlapped, they are thinly formed so as to have a desired film thickness, and these are placed on the surface of the substrate 4 and pressed. Thereafter, there is a method of bonding each layer to the surface of the substrate 4 by heat treatment.

In the present embodiment, yttria is used as an example of the yttrium oxide used for the corrosion-resistant film 2, but the present invention is not limited to this. Other yttrium oxides such as Y ₃ Fe ₅ O ₁₂ , YVO ₄ , YBa ₂ Cu ₃ O _{7 and the} like can also be applied.

  Next, an embodiment when the corrosion-resistant member 1 is actually installed in a semiconductor manufacturing apparatus will be described. FIG. 3 shows an inductively coupled plasma etching apparatus having a processing container 11 to which the corrosion-resistant member 1 of this embodiment is applied.

  The processing container 11 has a dome shape and has a rough surface portion 12 on the inner wall surface thereof. A metal lower chamber 13 is provided under the processing container 11 so as to be in close contact with the processing container 11. The corrosion resistant film of the present embodiment is formed on the surface of the rough surface portion on the inner surface of the processing container 11. A support table 14 is disposed on a base 20 in the upper part of the lower chamber 13.

  An electrostatic chuck 15 is provided on the support table 14, and a semiconductor wafer 16 is placed on the electrostatic chuck 15. A direct current power source is connected to the electrode of the electrostatic chuck 15, thereby electrostatically adsorbing the semiconductor wafer 16. An RF power source is connected to the support table 14.

On the other hand, a vacuum pump 19 is connected to the bottom of the lower chamber 13. The inside of the lower chamber 13 can be evacuated. A gas supply nozzle 17 for supplying an etching gas such as CF ₄ gas is provided above the semiconductor wafer 16 above the lower chamber 13. An induction coil 18 is provided around the processing container 11. A microwave of 13.56 MHz, for example, is applied to the induction coil 18 from an RF power source.

In this etching apparatus, the inside of the chamber 13 is exhausted to a predetermined degree of vacuum by the vacuum pump 19. After the semiconductor wafer 16 is electrostatically attracted by the electrostatic chuck 15, power is supplied to the induction coil 19 from the RF power supply while supplying, for example, CF ₄ gas as an etching gas from the gas supply nozzle 17. As a result, plasma of an etching gas is formed in the upper part of the semiconductor wafer 16, and the semiconductor wafer 16 is etched into a predetermined pattern. Note that the anisotropy of etching can be increased by supplying power to the support table 14 from a high-frequency power source.

During such an etching process, the inner surface of the processing vessel 11 is corroded by CF ₄ gas or plasma thereof. Therefore, since the corrosion resistance member 1 of the present embodiment is excellent in corrosion resistance, the container life is longer than that in the case of using a conventional alumina processing container.

  The corrosion-resistant member 1 of the present invention can be applied to members constituting the lower chamber 13, the electrostatic chuck 15, the support table 14, or a ring (not shown) for fixing and holding the semiconductor wafer 16, and the like. In order to show corrosion resistance and mechanical characteristics, the life of the apparatus is extended, maintenance is frequently performed, and it is not necessary to replace the member, so that the manufacturing cost of the semiconductor can be greatly reduced.

  Further, the corrosion-resistant member of the present embodiment is not limited to the processing container of the semiconductor manufacturing apparatus shown in FIG. 3, but can be applied to any part as a processing member using a corrosive gas such as an etching apparatus or CVD film formation. is there.

Corrosion-resistant member 1 of the present invention and a conventional corrosion-resistant member 1 in which an yttria film is formed on a base material 4 by thermal spraying and heat-treated to form an intermediate layer 3 made of a reaction product of yttria and alumina are manufactured to evaluate corrosion resistance. A test was conducted. The details will be described below.
<Manufacture of alumina substrate>
A commercially available alumina primary material having a purity of 99% by mass or more and an average particle diameter of 1 μm was purchased, and a binder and an aqueous solvent were added thereto to form a slurry. Thereafter, spray granulation was performed with a spray dryer to prepare an alumina secondary material. After granulation, the alumina secondary material was molded at a molding pressure of 100 MPa by a wet isostatic press molding method (rubber press method). And this was processed into the plate-shaped dimension of length 375mm, width 375mm, and thickness 12.5mm by cutting, and it was set as the molded object. The molded body after cutting is fired at a firing temperature of 1600 ° C. at a maximum temperature in a firing furnace in an air atmosphere, and grinding is performed after firing to obtain several plate-like bodies having a length of 300 mm, a width of 300 mm, and a thickness of 10 mm. I got it.
<Manufacture of corrosion resistant film>
First, a corrosion resistant film of the corrosion resistant member 1 of the present invention was manufactured. A predetermined amount of yttria and alumina are mixed and heated in a temperature range of 1000 to 1500 ° C. to obtain a raw material having a Y ₃ Al ₅ O ₁₂ composition, which is then finely pulverized to produce a YAG raw material having an average particle diameter of 0.8 μm Got. A YAM raw material having a Y ₄ Al ₂ O ₉ composition and an average particle size of 0.8 μm was also obtained in the same process.

  Furthermore, a commercially available yttria primary material having a purity of 99.5% by mass and an average particle size of 0.5 μm was prepared.

  Next, predetermined amounts of YAG, YAM and yttria primary materials, a binder and an organic solvent were mixed to form slurries. First, a slurry of YAG primary material was spray coated on the surface of the alumina substrate with a thickness of 15 μm, and dried by applying hot air at 120 ° C. for 10 minutes to form a first intermediate layer 3a made of YAG. Furthermore, the slurry which consists of a YAM primary raw material was spray-coated by the thickness of 15 micrometers on the surface of the 1st intermediate | middle layer 3a. Similarly to the above, the second intermediate layer 3b was formed by applying hot air at 120 ° C. for 10 minutes and drying. Next, the test piece which formed the slurry which consists of a yttria primary raw material with the thickness of 20 micrometers on the 2nd layer surface through the same process was obtained. Thereafter, the specimen was heat-treated at a maximum temperature of 1200 ° C. in an atmospheric furnace to obtain a sample of the corrosion-resistant member 1 of the present invention having a thickness of 40 μm.

On the other hand, a conventional corrosion-resistant member, which is a comparative example, is made from a sprayed material by introducing a certain amount of sprayed powder composed of oxygen, acetylene and yttria into the combustion chamber, igniting and exploding with a spark plug, and the energy generated by the explosion. A yttria sprayed powder was collided on an alumina substrate to form a sprayed film having a thickness of 40 μm by an explosion spraying method in which a sprayed coating was formed. This was heat-treated at a temperature of 1600 ° C. to produce a sample of a corrosion-resistant member having an intermediate layer made of a reaction product of yttria and alumina between the yttria sprayed film and the alumina substrate. The spraying conditions for forming the sprayed film include an O ₂ flow rate of 75 liters / min, a C ₂ H ₂ flow rate of 30 liters / min, an explosion cycle of 5 times / second, and an average particle size of Y ₂ O ₃ powder to be sprayed. The diameter was 10 μm and the melting rate was 70% or more.
<Evaluation of corrosion resistant film>
For this example and the conventional corrosion resistant member, first, 20 bending test pieces for a three-point bending strength test according to JIS R1601 were cut out from each sample in a form including a corrosion resistant film, and 15 of them were used for 3 A point bending strength test was conducted to evaluate the strength of the alumina base material including the corrosion resistant film.

  In addition, about the said strength test, in order to measure the intensity | strength of only the base material 4, the sample of the bending test piece size based on JISR1601 was cut out from the base material 4 by processing. Then, a test piece obtained by grinding the surface by 40 μm was prepared, a three-point bending strength test was performed, and the strength was compared with a sample on which a corrosion-resistant film was formed.

Moreover, the relative density of the film | membrane was calculated | required as follows using a bending test piece. First, the film density was measured by the X-ray reflectivity method. This was obtained by dividing this by the theoretical density (5.03 g / cm ³ ) of the Y ₂ O ₃ sintered body and multiplying this by 100.

Further, a part of the sample surface was masked, set in a RIE (Reactive Ion Etching) apparatus, and exposed to plasma in a Cl ₂ gas atmosphere for 3 hours. Etching of yttria sintered body (alumina content 99.5 mass%) with a density of 4.90 or more prepared as a reference sample by calculating the etching rate per minute from the dimensional difference between the front and back masking portions. The relative comparison value when the rate was 1 was determined as the etching rate ratio.

  About the average void ratio of the corrosion-resistant film 2 and the intermediate layer 3, the bending test specimen is subjected to precision processing so that the corrosion-resistant film 2 and the intermediate layer 3 can be observed, and each 100 μm × 100 μm range is imaged by SEM. The image was taken and this image was analyzed and calculated by an image analyzer (LUZEX-FS manufactured by Nireco).

Moreover, the arithmetic mean height (Ra) was measured with the non-contact-type surface roughness meter based on JISB0601-2001 using the bending test piece.
<Evaluation results and discussion>
The conventional corrosion-resistant member has a result that the three-point bending strength is lowered by 20% or more from the strength of the base material 4 alone. The relative density of the film was 60%, and the etching rate ratio was 2 or more. Further, the void ratio was 15% for the yttria sprayed film and 10% for the intermediate layer, and there were very many pores, and the arithmetic average height was 4 μm, which was a very rough surface property. From this result, it is considered that the strength reduction occurred because the Al component of the base material diffused into the yttria sprayed film in the heat treatment stage after the formation of the yttria sprayed film.

  Further, the yttria sprayed film had a relative density as low as 60% even after the heat treatment, and thus the etching rate ratio was as large as 2, resulting in poor corrosion resistance as compared with a dense yttria sintered body. In addition, it is considered that the etching rate ratio is influenced by the fact that the corrosion resistance film, the average void ratio of the intermediate layer, and the surface roughness are rough.

  In comparison with this, the corrosion-resistant member 1 of this example had a three-point bending strength equivalent to that of the base material 4 alone. The relative density of the film was as high as 90% or more, and the etching rate ratio was inferior to that of the yttria sintered body, but was kept as low as 1.5 or less. Further, the average void ratio is as low as 0.8%, 0.7%, and 0.5% for the corrosion-resistant film, the first intermediate layer 3a, and the second intermediate layer 3b, respectively, and the arithmetic average height on the surface of the corrosion-resistant film 2 is also 0. It was a smooth surface of 9 μm.

It is a schematic sectional drawing which shows typically one Embodiment of the corrosion-resistant member of this invention. It is a schematic sectional drawing which shows typically other embodiment of the corrosion-resistant member of this invention. It is a schematic sectional drawing which shows typically one Embodiment of the processing apparatus of this invention.

Explanation of symbols

1: Corrosion resistant member 2: Yttria film 3: Intermediate layer 3a: First intermediate layer 3b: Second intermediate layer 4: Base material 5: Third intermediate layer 10: Processing apparatus 11: Processing vessel 12: Rough surface portion 13: Chamber 14 : Support table 15: electrostatic chuck 16: semiconductor wafer 17: gas supply nozzle 18: induction coil 19: vacuum pump

Claims (5)

A corrosion-resistant member in which a corrosion-resistant film mainly composed of yttrium oxide is provided on a substrate mainly composed of alumina via an intermediate layer, and the intermediate layer is formed on the substrate side with Y ₃ Al ₅ O _12. And a second intermediate layer containing Y ₄ Al ₂ O ₉ as a main component on the corrosion-resistant film side. 2. The corrosion-resistant member according to claim 1, wherein an average void ratio of each of the corrosion-resistant film, the first intermediate layer, and the second intermediate layer is 1% or less. The corrosion-resistant member according to claim 1 or 2, wherein the arithmetic average height (Ra) of the surface of the corrosion-resistant film is 1 µm or less. 4. The corrosion-resistant member according to claim 1, further comprising a third intermediate layer containing YAlO ₃ as a main component between the first intermediate layer and the second intermediate layer. 5. A processing apparatus comprising a container whose inside is exposed to an environment of gas or plasma thereof, wherein the corrosion-resistant member according to any one of claims 1 to 4 is applied to at least a gas or plasma of components in the container. A processing apparatus characterized by being used on a surface to be exposed.

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