JP2002359230A - Plasma-resistant member and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Si-based plasma-resistant member having superior durability, and to provide a method for manufacturing the plasma-resistant member. SOLUTION: In the plasma-resistant member, the surface which is exposed to corrosive plasma is formed at least of an alloy of at least one kind of metal element selected from among the group of Y, Ce, La, Ba, and Zr and Si metal element as composition elements. In this case, the alloy composition base of the plasma-resistant member is, for example, CeSi2 , Y5 Si3 , Y5 Si4 , YSi2 , YSi2 , Y3 Si5 , BaSi, BaSi2 , Zr4 Si, Zr2 Si, or Zr5 Si3 .

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 a method of manufacturing the same, and more particularly, to an S-based member exhibiting excellent plasma resistance under a halogen-based corrosive gas atmosphere.
The present invention relates to an i-type member and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, an etching apparatus for performing fine processing on a semiconductor wafer is used as an etching apparatus.
An apparatus having a configuration including a plasma generation mechanism is used. For example, a dry etching apparatus whose configuration is schematically shown in cross section in FIG. 1 is known.

In FIG. 1, reference numeral 1 denotes an etching processing chamber having an etching gas supply port 2 and a vacuum exhaust port 3.
In the etching chamber 1, a lower electrode 5 on which a semiconductor wafer 4 to be processed is placed and a semiconductor wafer 4 facing the lower electrode 5 and placed on the surface of the lower electrode 5 are placed. An upper electrode 6 is provided so as to be able to advance and retreat so as to sandwich it.

[0004] Etching by this etching apparatus is
It is performed as follows. That is, for example, a semiconductor wafer 4 with a SiO ₂ film is placed on the lower electrode 5 surface,
The inside of the etching chamber 1 is evacuated and evacuated. After that, an etching gas of, for example, a CHF ₃ -Ar mixed system is supplied from the etching gas supply port 2. Next, the lower electrode 5
A required high-frequency current is caused to flow between the upper electrode 6 and the upper electrode 6, and the plasma energy generated between the electrodes 5
The O ₂ film is selectively etched. Thereafter, the etching gas is switched to a mixed system of Cl ₂ and O ₂ , and the selectively etched SiO ₂ film is used as a mask.
The semiconductor wafer 4 is selectively etched by the plasma energy.

In the above etching apparatus,
FIG. 2 shows a parallel-plate Si
Attention has been paid to using an electrode board made as the upper electrode 6. That is, since the Si single crystal or Si polycrystal has an electric resistance of about 1 to 50 Ω · cm and good plasma resistance, it is mounted on the upper electrode 6 ′ made of a parallel plate Si or the lower electrode 5. It is used as a pressing ring for pressing the edge of the placed semiconductor wafer 4.

Here, the parallel plate type Si electrode board 6 'is
For example, an outer diameter of 200 to 300 mm, a thickness of 5 to 10 mm,
A configuration in which hundreds to thousands of through holes 6a called shower holes having a diameter of about 0.5 mm are formed in the center portion is adopted. In the parallel plate type Si electrode board 6 ', the shower holes (through holes) 6a are reactive (etching).
It serves as a gas flow path, and when a high-frequency power source is applied, plasma energy is generated and acts to etch the semiconductor wafer 4 on the lower electrode 5 facing the same. The electric resistance of the parallel-plate Si electrode board 6 'is 1 to 50 Ω · cm.

[0007]

The parallel plate type Si electrode plate 6 'can apply plasma energy for etching to the opposing surface of the semiconductor wafer 4 at a substantially uniform density. Another advantage is that uniform etching can be easily performed. But,
Although the plasma resistance is good, the average life of these Si members is about 100 hours, and there is still a problem in terms of durability.

In particular, the etching environment has become more severe, such as the recent increase in plasma density, lower pressure, and diversification of etching gas types.
Consumption has increased and the frequency of replacement has inevitably increased. When the object to be etched is an insulating film having a low dielectric constant or the like, the frequency of replacement of the parallel plate type Si electrode board 6 ′ and the like increases because the consumption is more severe.

The short life expectancy of the parallel plate type Si electrode board 6 'and the like inevitably increases the frequency of replacement.
The operating rate of the etching apparatus decreases in accordance with the frequency of replacement. Further, the frequency of replacement of the parallel-plate Si electrode board 6 'and the like not only complicates the maintenance of the etching apparatus but also may cause variations in processing accuracy and quality depending on the timing of attachment / detachment / replacement. In any case, further improvement is desired in terms of productivity, yield of processed products, quality of processed products, and the like.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a Si-based plasma-resistant member having excellent durability and a method of manufacturing the same.

[0011]

According to the first aspect of the present invention, at least a surface layer exposed to a corrosive plasma has a Y, C
A plasma-resistant member characterized by being composed of an alloy containing at least one metal element selected from the group consisting of e, La, Ba and Zr and a Si metal element.

According to a second aspect of the present invention, in the plasma resistant member according to the first aspect, at least the surface layer is made of CeSi ₂ ,
Y ₅ Si ₃ , Y ₅ Si ₄ , YSi, YSi ₂ , Y ₃ Si
₅ , BaSi, BaSi ₂ , LaSi ₂ , Zr ₄ Si,
It is an alloy represented by a composition system of Zr ₂ Si or Zr ₅ Si ₃ .

According to a third aspect of the present invention, there is provided a high-temperature melting vessel in which metallic Si is accommodated and Y, Ce, La, Ba or Zr is contained.
Heating to a temperature equal to or higher than the melting point of the target alloy; and adding at least one metal selected from the group consisting of Y, Ce, La, Ba and Zr to the heat-melted Si; And forming a substantially uniform molten system while maintaining the melting temperature, followed by slow cooling.

According to a fourth aspect of the present invention, in the method for manufacturing a plasma-resistant member according to the third aspect, the surface of the Si-based substrate is coated with a substantially uniform molten system while maintaining the melting temperature.
It is characterized in that an alloy layer is formed in which at least one element selected from the group consisting of Ce, La, Ba and Zr and a Si element are contained.

According to a fifth aspect of the present invention, the surface of the Si-based substrate is Y, C
e, a step of closely adhering a metal layer made of at least one element selected from the group consisting of La, Ba and Zr; and heat-treating the Si-based substrate having the metal layer adhered thereto in a vacuum melting furnace, And a step of alloying with a metal having a base material surface closely contacted therewith.

The inventions of claims 1 to 5 are based on the following findings. That is, Y, C
An alloy composed of at least one metal selected from the group consisting of e, La, Ba and Zr and metal Si exhibits plasma resistance enough to withstand low pressure and high density plasma exposure. And have led to the invention described above.

More specifically, for example, when metallic Si (single crystal or polycrystal) is exposed to F (fluorine) based plasma, SiF ₄ is generated as a reaction product. The SiF ₄ is liable to volatilize and low boiling point (or melting point) is, SiF ₄
It was confirmed that the reaction proceeded sequentially, and as a result, the life was shortened. Incidentally, the boiling point of SiF ₄ is −86 ° C.

On the other hand, Si, such as CeSi ₂ , Y ₅ Si ₃
When alloys of Y, Ce, La, Ba, Zr, etc. are exposed to, for example, F-based plasma, SiF
₄ as well as CeF ₃ , YF ₃ , and LaF ₃ . Here, the boiling points (or melting points) of CeF ₃ , YF ₃ , LaF _{3, and the} like are significantly higher than SiF ₄ and are difficult to volatilize, and therefore, compared to metal Si (single crystal, polycrystal),
It was confirmed that etching was significantly suppressed and prevented, and the life was extended. Incidentally, the boiling point of CeF ₃ is 2300 ° C.
YF _{3 has} a boiling point of 2230 ° C., and BaF _{2 has} a boiling point of 22
60 ° C.

In the first to fifth aspects of the present invention, when the main body or the base material of the plasma resistant member is a metal, it is generally metal Si (polycrystal). In the case of alloy,
An alloy having a metal Si (polycrystalline) component of about 20 to 70 at%, more preferably about 30 to 50 at%. here,
The other metal element components of Y, Ce, La, Ba and Zr in the alloy system are about 80 to 30 atomic%, more preferably about 7 to 30 atomic%.
It is about 0 to 50 atomic%. Note that Y, Ce, La, B
The a and Zr components may be used alone or in a mixture of two or more.

The plasma resistant member according to the first and second aspects of the present invention can be easily manufactured by the manufacturing method according to the third to fifth aspects of the present invention.

The first means is to select a metal Si (polycrystal) and at least one metal component selected from the group consisting of Y, Ce, La, Ba and Zr to a required composition ratio, for example, a quartz glass crucible. First, metal Si is accommodated in a high-temperature melting container such as the one described above. Next, the metal Si is heated and melted at a temperature equal to or higher than the melting point of the target alloy with the added metal added for intermetallic compounding or alloying.

Thereafter, an additional metal component is added to the heat-melted metal Si, and the alloying proceeds while maintaining the melting temperature at the time of alloying. Subsequently, the required Si-based alloy can be easily obtained by gradually cooling the molten metal-based.
The melting container for high temperature may be, for example, a crucible made of tungsten or a crucible made of molybdenum instead of a crucible made of quartz glass. Further, as a modification of the first means, a casting method, a crystal pulling method, a method of coating the surface of the Si-based substrate with the above-mentioned molten metal, and the like can be mentioned.

The second means is to deposit a metal comprising at least one element selected from the group consisting of Y, Ce, La, Ba and Zr on the surface of a metal Si (polycrystalline) or Si-based alloy. The thin plates or foils are superimposed and closely attached and arranged by, for example, a uniaxial press. Then, the laminated body closely contacted and arranged is accommodated in, for example, an alumina container, and heated in a vacuum melting furnace at a temperature of, for example, 1000 to 1200 ° C. Then, the surface of the Si-based substrate is alloyed with a metal closely arranged, and at least the surface is made of CeSi ₂ , Y ₅ Si ₃ , Y
_{5 Si 4, YSi, YSi 2} , Y 3 Si 5, BaSi,
It is composed of an alloy layer represented by a composition system such as BaSi ₂ , LaSi ₂ , Zr ₄ Si, Zr ₂ Si, or Zr ₅ Si ₃ .

According to the first and second aspects of the present invention, an Si-based plasma-resistant member having more excellent plasma resistance than conventional plasma-resistant members made of Si single crystal or Si polycrystal is provided. That is, the plasma-resistant member according to the first and second aspects of the present invention reacts and generates a halide which is hardly volatilized on the surface when used in a region exposed to corrosive plasma of low pressure and high density. With the generation of these hard-to-evaporate halides, corrosion of the surface by corrosive plasma is prevented and suppressed, not only prolonging the life but also eliminating the possibility of particle contamination, and achieving high accuracy and reliability. It has a function suitable for high processing.

That is, by utilizing the good electrical characteristics of the Si-based member, and suppressing or preventing an increase in the cost of manufacturing a semiconductor manufacturing device or a semiconductor, high performance and high reliability are obtained without adversely affecting accuracy and the like. Effectively contributes to the manufacture and processing of semiconductors.

According to the third to fifth aspects of the present invention, it is possible to provide a Si-based plasma-resistant member having improved and improved plasma resistance with good yield and mass production.

[0027]

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments will be described.

Embodiment 1

First, a melting apparatus for Si using a quartz glass crucible as a melting tank is prepared. In this quartz glass melting tank, a Si powder or a lump of Si having a purity of 99.99% is prepared.
A lump of Ce having a purity of 99.99% is added, and stirring and melting are advanced. Here, the composition ratio of the Si component and the Ce component is Si / Ce = 2/1 in atomic ratio.

The temperature of the above Si-Ce molten system (1580 to
1620 ° C.) for about 3 hours and then 50-100 ° C. /
h, slowly cooled to a Si-Ce (CeSi ₂ )
Was produced (manufactured). Thereafter, CeSi ₂ was processed into a parallel plate type electrode board having an outer diameter of 200 mm, a thickness of 5 mm, and a through hole (shower hole) of 0.5 mm in the center at the center.

The above CeSi₂In the production and manufacture of the system,
Use Y, La, Ba or Zr instead of Ce component
And changing the composition ratio (atomic ratio) to the Si component,
The following 11 kinds of alloys were prepared (manufactured). So
After these Y₅Si₃, Y ₅Si₄, YSi, YSi
₂, Y₃Si₅, LaSi₂, BaSi, BaSi₂,
Zr₄Si, Zr₂Si, Zr₅Si₃Outside each
200mm diameter, 5mm thickness, 0.5mm diameter through center
Processed into a parallel plate type electrode board with through holes (shower holes)
did.

The above CeSi ₂ , Y ₅ Si ₃ , Y ₅ Si
_{4, YSi, YSi 2, Y} 3 Si 5, LaSi 2, Ba
Si, BaSi ₂ , Zr ₄ Si, Zr ₂ Si, Zr ₅ S
i ₃ made of the electrode plate of the parallel flat type, mounted as an upper electrode in the plasma etching apparatus configured as shown in FIG. 1, the frequency 13.56 MHz, high-frequency source 500 W,
High frequency bias 40 W, gas flow rate CF ₄ = 100 cc /
Table 1 shows the results of a plasma exposure test performed under severe conditions of min, gas pressure of 0.5 Pa (4 mTorr), plasma density of 1.7 × 10 ¹¹ atoms / cm ³ , and ion impact energy of 88 eV. For comparison, the results of tests and evaluations of a conventional parallel plate type electrode plate having the same shape and structure except that the material is Si single crystal (or Si polycrystal) under the same conditions are described below. Table 1
Shown in

[0034]

[Table 1]

As can be seen from Table 1, the plasma resistant member according to the example has a plasma corrosion resistance several hundred times that of the plasma resistant member according to the comparative example.
Damage due to plasma under corrosive gas, particles of SiF _{4 and} the like are also significantly suppressed. That is, not only high-precision processing and the like can be performed in a semiconductor manufacturing process or the like, but also the possibility of adversely affecting a workpiece can be eliminated.

In the above description, the whole is made of Si—Ce (C
eSi ₂ ) alloy is shown, for example, a thickness of 5 m
m of the molten Si-Ce
System, etc., and the surface layer is 0.1mm thick C
Similarly, the composite material composed of eSi ₂ or the like also had excellent plasma corrosion resistance.

Embodiment 2

Metallic Si having a purity of 99.99% and a thickness of 5 mm
Plate and metal Ce of 99.99% purity and 0.5 mm thickness
A thin plate was prepared. Next, a metal Ce thin plate was placed on one main surface of the metal Si plate, and 100 kgf / cm ² (9.807).
The metal Si plate and the metal Ce thin plate were brought into close contact with each other by uniaxial pressing (× 10 MPa). Thereafter, the adhered and laminated body is housed in a container made of alumina, and the container made of alumina is put in a vacuum melting furnace, and is heated at 1000 to 1100 ° C. for 1 hour.
Heat treatment was performed for a time. After the heat treatment, the sample to be heated is taken out of the container made of alumina, cut in the thickness direction, and subjected to EPMA.
When the cross section was observed at, one main surface of the metal Si plate was Ce
A composite member formed of the Si ₂ alloy layer was obtained.

In the production of the composite member, a thin plate of Y, La, Ba or Zr is used in place of the Ce thin plate, and the composition ratio (atomic ratio) to Si is changed to change the metal Si.
Eleven types of composite members were prepared in which alloy layers having different composition systems were provided on one main surface of the plate. That is, one main surface of the metal Si plate is formed of Y ₅ Si ₃ , Y ₅ Si ₄ , YSi, YSi ₂ , and Y ₃ S.
i ₅ , LaSi ₂ , BaSi, BaSi ₂ , Zr ₄ S
i, a composite member having an alloy layer as shown by the composition system of Zr ₂ Si or Zr ₅ Si ₃ was obtained. The heat treatment for surface alloying in the production process of the composite member is as follows.
For example, laser irradiation may be performed.

Next, using a parallel plate type plasma etching apparatus, a plasma exposure test was performed on the composite member manufactured under the following conditions. That is, for the alloy layer surface of the composite member, the frequency is 13.56 MHz, the high frequency source is 500 W, the high frequency bias is 40 W, and the gas flow rate is C.
F ₄ = 100 cc / min, gas pressure 0.5 Pa (4 mT
orr), plasma density 1.7 × 10 ¹¹ atoms /
A plasma exposure test was performed under severe conditions of cm ³ and ion impact energy of 88 eV. As a result, Example 1
As in the case of the above, damage by plasma under corrosive gas, particle contamination of SiF _{4 and} the like were prevented and suppressed, and it was confirmed that they exhibited excellent plasma corrosion resistance.

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, C which forms an alloy with Si
e, Y, La, Ba, Zr, and the like may be configured by combining two or more kinds.

[0042]

According to the first and second aspects of the present invention, a Si-based plasma-resistant member having more excellent plasma resistance than conventional plasma-resistant members made of Si single crystal or Si polycrystal. Is provided. In other words, when used in areas exposed to low-pressure, high-density corrosive plasma, corrosion of the surface due to corrosive plasma is prevented and suppressed, not only extending the life but also eliminating the possibility of particle contamination. In addition, it is possible to provide a plasma-resistant member that is suitable for high-accuracy, highly reliable processing and the like.

According to the third to fifth aspects of the present invention, it is possible to provide a Si-based plasma-resistant member having improved and improved plasma resistance with high yield and mass production.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a plasma etching apparatus.

FIG. 2 is a cross-sectional view showing a schematic configuration of a parallel plate type Si electrode board provided in the plasma etching apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Etching chamber 2 ... Etching gas supply port 3 ... Vacuum exhaust port 4 ... Semiconductor wafer 5 ... Lower electrode 6,6 '... Upper electrode 6a ... Through hole (shower hole)

Continued on the front page (72) Inventor Keiji Morita 1573-8 Onumada, Togane-shi, Chiba Toshiba Ceramics Co., Ltd. Togane Plant (72) Inventor Masahiko Ichijima 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. F term in the company development laboratory (reference) 5F004 AA16 BA04 BB29 DA16 DA23 DB03

Claims (5)

[Claims] At least a surface layer exposed to corrosive plasma is made of an alloy containing at least one element selected from the group consisting of Y, Ce, La, Ba and Zr and a Si element. A plasma-resistant member. 2. At least the surface layer is made of CeSi ₂ , Y ₅
Si ₃ , Y ₅ Si ₄ , YSi, YSi ₂ , Y ₃ Si ₅ ,
BaSi, BaSi ₂ , LaSi ₂ , Zr ₄ Si, Zr
₂ Si, or plasma-resistant member according to claim 1, characterized in that an alloy represented by the composition system of the Zr ₅ Si _3. 3. A high-temperature melting container containing metal Si,
A step of heating the alloy with Y, Ce, La, Ba or Zr to a temperature equal to or higher than the melting point of the target alloy; and forming the heat-melted Si with at least one selected from the group consisting of Y, Ce, La, Ba and Zr. A method of manufacturing a plasma-resistant member, comprising: a step of adding a metal of step (b); and a step of forming a substantially uniform molten system while maintaining the melting temperature, and then gradually cooling. 4. An Si-based substrate surface is coated with a substantially uniform molten system while maintaining the melting temperature, and Y, Ce, La, and Ba are coated.
4. The method for producing a plasma-resistant member according to claim 3, wherein an alloy layer containing at least one element selected from the group consisting of Zr and Zr and a Si element is formed. 5. The method according to claim 5, wherein Y, Ce, La, and Ba are formed on the surface of the Si-based substrate.
And a step of closely disposing a metal layer made of at least one element selected from the group consisting of Zr and Zr. And a step of alloying with the arranged metal.