Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
2000-01-31
2002-06-18
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S689000, C428S696000
Reexamination Certificate
active
06406799
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing an anti-corrosion member and an anti-corrosion member.
2. Description of Related Art
In accordance with an enlargement of memory storage in super LSI, a micro-fabrication technique is improved more and more, and a process which requires a chemical reaction is improved accordingly. Particularly, in a semiconductor manufacturing apparatus which requires a super clean condition, use is made of a corrosion gas of halogen series such as chlorine gas, fluorine gas and so on as a deposition gas, an etching gas and a cleaning gas.
For example, in the semiconductor manufacturing apparatus such as a thermal CVD apparatus, use is made of a semiconductor cleaning gas made of a corrosion gas of halogen series such as ClF
3
, NF
3
, CF
4
, HF and HCl after a deposition operation. Moreover, even in the deposition operation, use is made of a corrosion gas of halogen series such as WF
6
, SiH
2
Cl as a film forming gas.
Members constructing the semiconductor manufacturing apparatus are formed, for example, by anodized aluminum, aluminum nitride and so on.
Recently, it is found that silicon carbide (SiC) shows a relatively high anti-corrosion property with respect to the corrosion gas of halogen series mentioned above, and thus SiC is gradually used for the construction members of the semiconductor manufacturing apparatus.
Further, Japanese Patent Laid-Open Publication No.2-263972 (JP-A-2-263972) discloses a technique such that a fluorine passivated film made of a metal fluoride as a main ingredient in a stoichiometric state is formed on a surface of a metal member and an anti-corrosion property of the metal member with respect to the corrosion gas of halogen series is improved by the thus formed fluorine passivated film.
However, in the anodized aluminum, a surface oxidization film is shrunk at a temperature about 300° C. and thus cracks are generated. Therefore, if it is exposed in the corrosion gas of halogen series at a high temperature, a base aluminum is corroded via crack portions, and the surface oxidization film corresponding to the thus corroded portion is peeled off from the member to generate particles.
Moreover, in aluminum nitride, there is a tendency such that use is made of a highly corrosion gas such as NF
3
for the purpose of increasing an etching speed. Therefore, there is a drawback such that, if it is exposed in this highly corrosive gas at a high temperature, as in the case of anodized aluminum, a surface thereof is corroded and particles are generated. If the thus generated particles are sedimented on a base member provided in a semiconductor manufacturing apparatus, there occurs a phenomenon such as an insulation defect and a conduction defect, and these defects become a cause of a semiconductor defect.
Further, as mentioned above, silicon carbide shows a relatively high anti-corrosion property with respect to the corrosion gas of halogen series, but there is a drawback such that it is difficult to make a large construction member by using silicon carbide since it is hard to be sintered.
Here, there is a trial such that a porous member made of silicon carbide is formed, and then aluminum and so on are immersed in pores of the thus formed porous member to manufacture a large construction member. However, since an anti-corrosion property of the thus immersed aluminum is low, the thus manufactured large construction member has also a low anti-corrosion property with respect to the corrosion gas of halogen series, so that there is a drawback such that applicable fields of the thus manufactured large construction member are limited.
Further, in the method disclosed in JP-A-2-263972, there is a drawback such that an anti-corrosion property with respect to a plasma gas of halogen series especially with respect to a chlorine plasma gas is extremely low.
SUMMARY OF THE INVENTION
An object of the invention is to provide a new method of producing an anti-corrosion member and an anti-corrosion member which shows a high anti-corrosion property with respect to a corrosion gas of halogen series.
According to the invention, a method of producing all anti-corrosion member having a base member made of a metal in which aluminum is included, ceramics in which an aluminum element is included, or a composition member constructed by a metal in which aluminum and ceramics are included, and an anti-corrosion film formed on the base member, comprises the steps of: setting the base member in a container in which a solid fluorine compound is filled; heating the container at a temperature higher than a decomposition temperature of the fluorine compound to generate a decomposed gas of the fluorine compound and to subject the base member to a heat treatment with the decomposed gas of the fluorine compound; and forming an anti-corrosion film made of a fluoride on a surface of the base member.
Moreover, according to the invention, an anti-corrosion member comprises a base member made of a metal in which aluminum is included, ceramics in which an aluminum element is included or a composite member constructed by a metal in which aluminum and ceramics are included, and an anti-corrosion film made of a fluoride generated on a surface of the base member by setting the base member in a container in which a solid fluorine compound is filled and by heating the container at a temperature higher than a decomposition temperature of the solid fluorine compound.
The inventors attempted to find a new method of producing an anti-corrosion member and a new anti-corrosion member so as to improve an anti-corrosion property of a member which constructs a semiconductor manufacturing apparatus with respect to a corrosion gas of halogen series especially a plasma gas of halogen series.
As a result, it was found that a fluoride layer preferably having a main crystal phase of AlF
3
was formed on a surface of a base member by setting the base member made of aluminum in a sealed container in which a solid fluorine compound such as NaHF
2
is included and by heating the sealed container at a temperature higher than a decomposition temperature of the fluorine compound to perform a heat treatment for a predetermined time interval. Then, it was found that the thus formed anti-corrosion member had a high anti-corrosion property with respect to the corrosion gas of halogen series, especially the plasma gas of halogen series such as a chlorine plasma gas.
The base member mentioned above is formed by aluminum metal, an aluminum alloy, ceramic material in which an aluminum element is included, and a composite member. Therefore, it is possible to easily perform casting and sintering operations, and thus a manufacturing of the large construction member becomes easy.
Therefore, the anti-corrosion member manufactured according to the method of the invention has an excellent anti-corrosion property with respect to the corrosive gas of halogen series, and it is possible to easily manufacture the large construction member by using this anti-corrosion member. In addition, it is not necessary to use complicated manufacturing equipment, and thus problems associated with high cost manufacturing operations are limited.
FIG. 1
is a schematic view showing an X-ray diffraction pattern of an anti-corrosion member according to the invention. Moreover,
FIG. 2
is an SEM cross sectional photograph showing a surface of the anti-corrosion member mentioned above.
From the X-ray diffraction pattern shown in
FIG. 1
, it is possible to observe a peak from AlF
3
crystal phase other than a peak from aluminum which constructs the base member. That is to say, it is understood that a fluoride in which AlF
3
is included as a main crystal phase is formed on a surface of the member obtained according to the method of the invention.
Moreover, from the SEM cross sectional photograph shown in
FIG. 2
, it is understood that a film having a layer a thickness of which is about 4 &mgr;m is formed.
In the producing method according to the invention, a mechanism
Aihara Yasufumi
Araki Kiyoshi
Watanabe Keiichiro
Burr & Brown
Jones Deborah
NGK Insulators Ltd.
Piziali Andrew T
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