JP2002029831A - Plasma resistant member and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma resistant member which sufficiently withstands exposure of a corrosion resistant plasma and with which the peeling, desorbing, etc. of a deposited film are sufficiently suppressed and prevented. SOLUTION: At least the surface part of a first invention consists substantially of a sintered yttrium aluminate garnet compact and its mean surface roughness (Ra) is 1.2 to 2.5 μm. At least the surface part of a second invention consists substantially of the sintered yttrium aluminate garnet compact and the tangent angle θ of the rugged surface of the surface part to a horizontal plane is -55 to +55 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma-resistant member, and more particularly, to a plasma-resistant member which not only exhibits excellent plasma resistance under a halogen-based corrosive gas atmosphere but also suppresses particle contamination and the like. The present invention relates to a sex member.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, an etching apparatus or a sputtering apparatus for performing fine processing on a semiconductor wafer or a C for forming a film on a semiconductor wafer is used.
VD devices and the like are used. These manufacturing apparatuses employ a configuration including a plasma generation mechanism for the purpose of high integration. For example, as schematically shown in FIG. 3, an etching apparatus using electron cyclotron resonance having a microwave generation chamber 1 and a processing chamber 2 is known.

[0003] Here, the microwave generation chamber 1 and the processing chamber 2 are separated from each other by a microwave introduction window 3, and a coil 4 for forming a magnetic field is arranged around the processing chamber 2. Further, the processing chamber 2 has a gas supply port 5 for supplying an etching gas, and a gas exhaust port 6 for evacuating the processing chamber 2 to a vacuum.
And a monitoring window 7 for monitoring the inside of the processing chamber 2, and a support / mounting table 9 for supporting the semiconductor wafer 8 directly or via a susceptor (not shown) is installed in the processing chamber 2. .

[0004] Etching by this etching apparatus is performed as follows. That is, after the semiconductor wafer 8 is mounted on the support / mounting table 9 and the inside of the processing chamber 2 is evacuated, the etching gas is supplied. On the other hand, high-density plasma is generated by introducing a microwave from the microwave generation chamber 1 into the processing chamber 2 through the microwave introduction window 3 and energizing the coil 4 to generate a magnetic field. The etching energy is decomposed into an atomic state by the plasma energy, and the surface of the semiconductor wafer 8 is etched.

In this type of manufacturing apparatus, a chlorine-based gas (such as boron chloride (BC) is used as an etching gas.
1)) or a corrosive gas such as a fluorine-based gas (for example, fluorocarbon (CF ₄ )). Therefore, components that are exposed to plasma in a corrosive gas atmosphere, such as the inner wall of the processing chamber 2, the monitoring window 7, the microwave introduction window 3, and the support / mounting table 9, basically have plasma resistance. Required. In response to such demands, alumina-based sintered bodies, silicon nitride-based sintered bodies, aluminum nitride-based sintered bodies, and the like have been used as the plasma-resistant members.

[0006]

However, plasma-resistant members such as the above-mentioned alumina-based sintered bodies, silicon-nitride-based sintered bodies, and aluminum-nitride-based sintered bodies gradually become exposed to plasma in a corrosive gas atmosphere. Corrosion progresses, and crystal particles constituting the surface are detached, so-called particle contamination occurs. That is, there is a problem that the detached particles adhere to the surface of the semiconductor wafer 8, the support / mounting table 9, and the like, adversely affect the etching accuracy and the like, and the performance and reliability of the semiconductor are easily impaired.

Also, in a CVD apparatus, corrosion resistance is required because the apparatus is exposed to a fluorine-based gas such as fluorine nitride (NF ₃ ) under plasma during cleaning.

In order to solve the above-mentioned problem of corrosion resistance, a plasma-resistant member made of a sintered body of yttrium aluminate garnet (so-called YAG) has been proposed (for example, JP-A-10-45461 and JP-A-10-23687).
No. 1). That is, the surface exposed to plasma in a halogen-based corrosive gas atmosphere is formed of a sintered body mainly composed of a composite oxide such as spinel having a porosity of 3% or less, cordierite, yttrium aluminate garnet, and the like, and A plasma-resistant member whose surface has a center line average roughness (Ra) of 1 μm or less is known.

However, although the yttrium aluminate garnet-based sintered body is excellent in plasma resistance, it is suitable for miniaturization of an etching process or a film-forming process, or enlargement of a workpiece. Not enough. That is, when a fluorine-based gas is used for an etching process in a dry process in manufacturing a semiconductor, particularly, in an etching process, a fluorocarbon polymer is deposited. Then, the deposited so-called deposition film is easily peeled off by a thermal cycle, and becomes dust on the surface of the semiconductor wafer to cause a failure.

In this regard, more specifically, the sintered body of yttrium aluminate garnet or the like has a densified (porosity of 3% or less) and a center line average roughness (Ra) of 1 surface.
By making the surface flat to not more than μm, the progress of etching is hindered, and as a result, the plasma resistance is improved. But,
The plasma processing is usually a repetitive operation of discharge and replacement of the semiconductor wafer 8, and cooling is also performed to protect a resist film and the like of the semiconductor wafer 8, so that a so-called thermal cycle is repeated. In this sense, the flat surface of the plasma resistant member is, on the other hand,
The deposition film deposited during the etching process or the like is likely to be peeled off.

Here, the particles deposited once or the deposited deposition film are peeled off by a plasma-resistant member, for example, a ring-shaped pressing member for pressing and holding the peripheral portion of the semiconductor wafer 8 mounted on the support / mounting table 9. This causes a problem that the semiconductor wafer 8 detaches and adheres to the surface of the semiconductor wafer 8. That is,
The processing accuracy is impaired, and the reliability and yield of the processed product are significantly impaired, resulting in inconvenience in manufacturing cost and productivity.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a plasma-resistant member which can withstand corrosive plasma exposure sufficiently, and in which separation and detachment of a deposition film are suppressed or prevented. I do.

[0013]

According to a first aspect of the present invention, at least a surface portion exposed to plasma is substantially made of a yttrium aluminate garnet-based sintered body, and has an average surface roughness (Ra) of 1. A plasma-resistant member having a thickness of 2 to 2.5 μm.

According to a second aspect of the present invention, at least the surface portion exposed to the plasma is substantially made of a yttrium aluminate garnet-based sintered body, and the tangent angle θ of the uneven surface to the horizontal plane is -55 to +55 degrees. A plasma-resistant member characterized by the following.

According to a third aspect of the present invention, in the plasma resistant member according to the first or second aspect, the porosity of the yttrium aluminate garnet-based sintered body forming the surface portion exposed to plasma is substantially 1%. It is characterized by the following.

The inventions of claims 1 to 3 have been made based on the following findings. That is, in a plasma-resistant member exposed to plasma in a corrosive gas atmosphere, flatness with a surface average roughness (Ra) of 1 μm or less is a common sense. However, even if the surface average roughness (Ra) is out of the range, depending on the degree of flatness and the nature of the irregularities, plasma resistance is not impaired, and particles or deposits deposited or deposited by the so-called anchor effect are not impaired. The inventors have found that the peeling resistance of the film is improved, and the occurrence of defective dust is also eliminated.

When the porosity of the yttrium aluminate garnet-based sintered body forming the surface portion exposed to the plasma is substantially 1% or less, it is effective in terms of corrosion resistance. That is, if the porosity of the surface sintered body exceeds 1%, erosion tends to proceed from the edge of the pore,
It is preferable that the porosity is low to cause a disadvantage in terms of plasma resistance.

In the first to third aspects of the present invention, the plasma-resistant member is usually a sintered body substantially made of yttrium aluminate garnet, but may be made of alumina, zirconia or the like in consideration of mechanical strength. May be used as a substrate, and the surface may be integrally coated with a yttrium aluminate garnet-based sintered layer. In other words, it is a composite type that uses ceramics as a base material that contributes to mechanical strength and cost reduction even if there is a problem in plasma resistance, and that a portion exposed to plasma is formed of a yttrium aluminate garnet-based sintered layer. You may.

Here, it is desirable that the yttrium aluminate garnet-based sintered body is made of yttrium aluminate garnet having a purity of 99.5% or more. That is, when the purity is 99.5% or more, the average crystal grain size of the sintered body is easily controlled in the range of about 5 to 40 μm, and a sintered body having a uniform particle diameter is formed. Furthermore, when it is mentioned that when the sintered body is composed of yttrium aluminate garnet having a purity of less than 99.5%, large crystal grains and small crystal grains in a matrix form are mixed in the sintered body. It becomes difficult to control within the range. Further, the difficulty in controlling the surface roughness makes it difficult to stably produce a dense sintered body, which may result in an increase in porosity.

According to the first aspect of the present invention, in the plasma-resistant member having at least a surface portion substantially made of a sintered body of yttrium aluminate garnet, the average roughness (Ra) of the surface exposed to plasma is at least 1.2. ~ 2.5 μm
Must be selected within the range. Here, if the surface average roughness (Ra) is less than 1.2 μm, the anchor effect is insufficient, and the phenomenon of separation of the deposited or deposited particles and the deposited film cannot be avoided or eliminated. In addition, even if the thickness exceeds 2.5 μm, the anchor effect tends to decrease, and the plasma resistance is impaired.

According to the second aspect of the present invention, the plasma-resistant member having at least a surface portion substantially composed of a sintered body of yttrium aluminate garnet is provided with a surface average roughness (R).
Without being influenced by a), the tangent angle θ of the surface unevenness with respect to the horizontal plane must be selected within the range of −55 to +55 degrees.

If the tangent angle θ is out of the range of -55 to +55 degrees, the plasma resistance is impaired. Note that the tangent angle θ
Is the angle θ formed by the tangent of the uneven surface to the horizontal plane, as schematically shown in FIG. 1. Regardless of the average surface roughness (Ra), the angle of the tangent that influences the anchor effect is emphasized.

The plasma resistant member according to the first to third aspects of the present invention can be manufactured by conventional means. That is, a slurry obtained by stirring and mixing a magnesia component, a binder resin, and a medium liquid into a raw material powder mainly composed of yttrium aluminate garnet particles having an average particle size of 0.1 to 1.0 μm is prepared by, for example, a rotary ball mill. I do. Further, the prepared slurry is granulated by, for example, a spray drier method, formed by an isostatic pressing method or the like, and the formed body is subjected to calcination and degreasing. The molding of the raw material powder may be performed by molding means such as extrusion molding, injection molding, casting molding, etc., instead of using the isostatic press.

Next, the calcined and degreased molded body is subjected to vacuum sintering treatment or 1700 to 1
By performing the sintering treatment at a temperature of about 800 ° C., a sintered body of yttrium aluminate garnet is obtained.
Here, the sintered body desirably has a crystal grain size of about 5 to 40 μm, and the surface roughness (R
When a) is outside the range of 1.2 to 2.5 μm, or when the tangent angle θ of the uneven surface is outside the range of −55 to +55 degrees, mechanical polishing or chemical polishing is performed. And so on so that the surface roughness (Ra) or the like falls within the above range.

According to the first to third aspects of the present invention, the average roughness (Ra) of the surface of the sintered body or the taper or slope of the surface unevenness is selected and set within an appropriate range, so that the so-called anchor effect can be effectively reduced. It has a configuration that is provided. That is, at least the area surface exposed to plasma is formed of a sintered body layer having excellent plasma resistance,
By imparting an appropriate anchor effect to the sintered body layer, detachment of particles or deposition films deposited and deposited in the plasma processing process is prevented or eliminated.

Therefore, the present invention effectively contributes to the production and processing of semiconductors with high performance and reliability without adversely affecting the quality and precision of film formation while preventing increase in the production cost of the production apparatus or semiconductor. I do.

[0027]

An embodiment will be described below with reference to FIG.

Yttrium aluminate garnet (YAG) particles 10 having a purity of 99.9% and an average particle size of 0.5 μm
An appropriate amount of ion-exchanged water and 2% by weight of polyvinyl alcoholate are added to 0% by weight, and stirred and mixed to prepare a slurry. Next, the slurry thus prepared was granulated with a spray dryer, and the obtained granulated powder was molded by molding.
9.807 × 10 ⁵ MPa (1000 kgf / c
m ² ), molded at a pressure of 12 mm, inner diameter 210 m
m and a molded body having an outer diameter of 260 mm were obtained.

After subjecting the above molded body to calcination and degreasing at 900 ° C. in air, 1.33 Pa
Sintering and sintering were performed at a temperature of 1750 ° C. in a vacuum of (0.01 Torr) or less to prepare 12 types of ring-shaped yttrium aluminate garnet-based sintered bodies having a porosity of 0.1 to 0.3%. Next, each of the ring-shaped sintered bodies of yttrium aluminate garnet was machined with a diamond grindstone to obtain ring-shaped sintered bodies having a thickness of 10 mm, an inner diameter of 200 mm, and an outer diameter of 250 mm.

Thereafter, lapping and grinding are further performed.
By sandblasting, surface average roughness (Ra) 0.1
The surface roughness was finished to 0 to 3.00 μm to produce an 8-inch semiconductor wafer holding member 10 whose main configuration is shown in cross section in FIG.

The wafer holding member 10 was mounted on a parallel plate type RIE apparatus, and the frequency was 13.56 MHz.
z, high frequency source 500 W, incident ion energy 80
eV, plasma density 7 × 10 ¹¹ atms / cm ³ , C
F ₄ , 100 scc, gas pressure 0.5 × 133 Pa (0.
A plasma exposure test was performed under the conditions of 5 Torr) to determine the number of particles attached to the semiconductor wafer surface.
Table 1 shows the results of evaluating the delamination resistance by the integration time until the number of particles having a particle size of 0.2 μm or more exceeds 30.

[0032]

[Table 1]

As can be seen from Table 1, in each of the plasma-resistant members according to the examples, the integration time until the number of particles having a size of 0.2 μm or more exceeds 30 is significantly increased as compared with the comparative example. are doing. That is, it was confirmed that it functions as the wafer holding member 10 exhibiting excellent plasma resistance and dust resistance.

An appropriate amount of ion-exchanged water and 2% by weight of polyvinyl alcohol are added to 100% by weight of yttrium aluminate garnet particles having a purity of 99.9% and an average particle diameter of 0.5 μm, and stirred and mixed to prepare a slurry. .
Next, the slurry thus prepared was granulated with a spray dryer, and the obtained granulated powder was subjected to 9.807 × 10 ⁵ MPa (1000 kgf) with a hydrostatic press (CIP press).
/ Cm ² ) at a pressure of 10 mm in thickness and 100 in width.
mm and a length of 100 mm were obtained.

After subjecting a part of the compact to calcination and degreasing at a temperature of 900 ° C.,
Sintering and firing treatment was performed at a temperature of 50 ° C. to obtain a yttrium aluminate garnet-based sintered body. Next, a test piece was cut out from the yttrium aluminate garnet-based sintered body, and the test piece was subjected to lapping, grinding, sand blasting, and the like to obtain a surface average roughness (R).
a) The surface roughness was finished to about 0.1 to 0.5 μm. The tangent angle θ of the processed uneven surface with respect to the horizontal plane was measured for the surface roughness finished test piece.
It was in the range of 45 to +45 degrees.

Next, the test piece was mounted on a parallel plate type RIE apparatus, and the frequency was 13.56 MHz, the high frequency source was 500 W, the incident ion energy was 80 eV, the plasma density was 7 × 10 ¹¹ atms / cm ³ , CF ₄ , 100 sc
c, When a plasma exposure test was performed under the conditions of a gas pressure of 0.5 × 133 Pa (0.5 Torr), the etching rate was 50 Å / hour.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, vacuum firing / sintering temperature, firing / sintering temperature in air atmosphere, raw material composition of yttrium aluminate garnet, and the like can be appropriately changed within an allowable range.

[0038]

According to the first to third aspects of the present invention, the yttrium aluminate garnet-based sintered body having excellent plasma resistance can be used, and the possibility of particle contamination due to the separation or separation of a deposit film or the like can be eliminated. A plasma resistant member is provided. That is, in the configuration of the region exposed to the plasma containing the corrosive gas, while having excellent durability, there is no possibility of causing particle contamination, so that the reliability of the semiconductor and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a definition of a tangent angle θ of an uneven surface of a surface of a plasma-resistant member according to an example.

FIG. 2 is a cross-sectional view illustrating a configuration of a main part of the plasma-resistant member according to the embodiment.

FIG. 3 is a sectional view showing a schematic configuration of a plasma etching apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Microwave generation chamber 2 ... Processing chamber 3 ... Microwave introduction window 4 ... Magnetic field forming coil 5 ... Gas supply port 6 ... Gas discharge port 7 ... Monitoring window 8 ... Semiconductor wafer 9 ... Semiconductor wafer support / mounting table 10 ... Semiconductor wafer holding member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Ichijima 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. (72) Inventor Mitsuhiro Fujita 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. Inside the Company Development Laboratory (72) Inventor Akira Miyazaki 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. (72) Inventor Shuzo Shimai 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. In-house (72) Inventor Shuichi Saito 33, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Production Technology Center (72) Inventor Katsuaki Aoki 33, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Production Co., Ltd. Inside the Technology Center (72) Inventor Eriko Nishimura 33, Shinisogo-cho, Isogo-ku, Yokohama, Kanagawa Co., Ltd. Toshiba production technology center in the F-term (reference) 4G031 AA08 AA29 BA26 CA01 CA07 5F004 AA15 AA16 BB29 DB08 5F045 BB14 BB17 EB03 EC05 EM09

Claims (3)

[Claims] At least a surface portion to be exposed to a plasma is substantially made of a sintered body of yttrium aluminate garnet, and has an average surface roughness (Ra) of 1.2 to 2.
A plasma resistant member having a thickness of 5 μm. 2. At least a surface portion exposed to plasma is substantially made of a sintered body of yttrium aluminate garnet, and a tangent angle .theta. Of a surface portion uneven surface to a horizontal plane is -55 to +55 degrees. Plasma resistant member. 3. The plasma resistant member according to claim 1, wherein the porosity of the yttrium aluminate garnet-based sintered body forming the surface portion is substantially 1% or less.