Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2002-07-17
2003-11-04
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of inorganic material
C501S010000, C501S153000, C501S152000
Reexamination Certificate
active
06641941
ABSTRACT:
This application claims the benefits of Japanese Patent Applications P2001-219,092, filed on Jul. 19, 2001, and P2002-180,769, filed on Jun. 21, 2002, the entireties of which are incorporated by reference.
BACKGROUND OF THE INVENTION
The invention relates to a method of producing a film of an yttria-alumina complex oxide, a film of an yttria-alumina complex oxide, a sprayed film, a corrosion-resistant member and a member effective for reducing particle generation.
In semiconductor manufacturing systems requiring a super clean state, halogen-based corrosive gases such as chlorine-based gases and fluorine-based gases are used as deposition gases, etching gases and cleaning gases. For example, these gases are used as cleaning gases for a semiconductor composed of a halogen-based corrosive gas such as CIF
3
, NF
3
, CF
4
, HF and HCl after the deposition stage in a semiconductor producing system, such as a hot CVD system. Further, halogen-based corrosive gases such as WF
6
, SiH
2
Cl
2
or the like are used for film formation in the deposition stage.
Further, in film-forming and etching stages of CVD or PVD processes, the chemical reactions for film formation or etching produce by-products, which are deposited onto a susceptor, an electrode or the parts constituting the chamber. Particularly, in a so-called cold wall type system, the chamber wall is low in temperature, so that particles may be easily deposited onto the cold chamber wall. Although such deposits are subjected to wet or dry cleaning processes at predetermined intervals, excessive deposits may fall or be moved onto a semiconductor wafer, resulting in instability of semiconductor processing or reduction of the production yield.
To prevent falling particles, it has been known to apply shot peening or blast treatments using glass beads on the surface of a metal plate to increase the surface roughness, so that the retention force of the metal surface may be improved.
It has been thus desired to form a film that is highly resistive against halogen-based gases or plasmas and which is stable over a long time period on a member used for a semiconductor-producing system, such as a member contained in the chamber or the inner wall surface of the chamber. Further, when by-products are deposited on a member contained in the system or the inner wall surface of the chamber, it is desired that the deposited by-products are retained thereon for a long time period.
The assignee filed a Japanese patent application P2001-110,136. According to the disclosure, it is possible to form a film of an yttria-alumina complex oxide on a substrate by spraying and to provide a high anti-corrosion property against a halogen-based gas plasma, thus preventing the particle generation. The corrosion-resistant film, however, might leave the following problems. That is, cracks may be induced in the film depending on the conditions for spraying. The sprayed film may be subjected to a heat treatment at a high temperature. Such heat treatment may induce cracks in the film. If cracks are generated in the film of an article having a substrate and the film, such film may be easily peeled from the substrate to generate particles and reduce the anti-corrosion property against a corrosive substance. The resulting article may be undesirable, thus reducing the production yield.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a film of an yttria-alumina complex oxide having a high peel strength on a substrate.
Another object of the invention is to provide a member effective for reducing particle generation and having a high capability for retaining deposits and that is usable for a long time period with improved stability.
Still another object of the invention is to provide a member effective for reducing particle generation and having a high capability for retaining deposits on the surface, so as to reduce the number of fallen particles due to the deposits on the member and reduce the down time associated with maintenance of a system applying the member.
A first aspect of the invention provides a method of producing a film of an yttria-alumina complex oxide, the method comprising the step of spraying a mixed powder of powdery materials of yttria and alumina onto a substrate to produce a sprayed film composed of an yttria-alumina complex oxide.
Further, the invention provides a film of an yttria-alumina complex oxide obtained by the above method.
Further, the invention provides a film of an yttria-alumina complex oxide, wherein the yttria-alumina complex oxide comprises those of garnet and perovskite phases and a ratio YAL(
420
)/YAG(
420
) is not lower than 0.05 and not higher than 1.5, provided that the ratio YAL(
420
)/YAG(
420
) is the ratio of a peak strength YAL (
420
) of the (
420
) plane of the perovskite phase to a peak strength YAG (
420
) of the (
420
) plane of the garnet phase. The peak strengths are measured by X-ray diffraction method.
Further, the invention provides a film formed by spraying, the film being made of an yttria-alumina complex oxide and free from a crack having a length not smaller than 3 &mgr;m and a width not smaller than 0.1 &mgr;m.
Further, the invention provides a corrosion-resistant member comprising a substrate and a film of an yttria-alumina complex oxide, wherein the yttria-alumina complex oxide comprises those of garnet and perovskite phases and a ratio YAL(
420
)/YAG(
420
) is not lower than 0.05 and not higher than 1.5, provided that the ratio YAL(
420
)/YAG(
420
) is the ratio of a peak strength YAL (
420
) of the (
420
) plane of the perovskite phase to a peak strength YAG (
420
) of the (
420
) plane of the garnet phase. The peak strengths are measured by X-ray diffraction method.
The invention further provides a corrosion-resistant member comprising a substrate and a film formed by spraying. The film is made of an yttria-alumina complex oxide and free from a crack having a length not smaller than 3 &mgr;m and a width not smaller than 0.1 &mgr;m.
Further, a second aspect of the invention provides a member effective for reducing particle generation and comprising a substrate and a surface layer on the substrate. The surface layer has a, calculated according to the following formula, in a range of 50 to 700:
&agr;=(a specific surface area measured by Krypton adsorption method (cm
2
/g))×(a thickness of the surface layer (cm))×(a bulk density of the surface layer (g/cm
3
)).
The inventors conceived of spraying a mixed powder of powdery materials of yttria and alumina on a substrate to form a sprayed film of an yttria-alumina complex oxide, and tried the process. Consequently, they have successfully formed a film having a high peel strength on a substrate with improved stability.
The thus obtained film of an yttria-alumina complex oxide does not have substantial cracks and has a high peel strength with respect to the underlying substrate, thereby preventing the peeling of the film and particle generation in contact with a corrosive substance. Additionally, when such a film is subjected to heat treatment, the peel strength of the film with respect to the substrate may be further improved, and cracks not observed in the film after the heat treatment.
Moreover, it is possible to control or regulate the microstructure of the film by controlling the conditions for the spraying process and for the heat treatment. Specifically, a porous film substantially without closed pores, or a porous film having a high ratio of open pores to closed pores may be successfully produced. A member for a semiconductor-producing system may be advantageously produced using such a film and the underlying substrate. Such a member has an improved specific surface area, so that deposits may be firmly held on the surface of the member by an anchor effect to reduce the thickness of the deposits on the member. It is thus possible to produce a film having a specific a value according to the invention of the second aspect, which will be described later in detail.
In a preferred embodiment, the powdery material of yt
Ohashi Tsuneaki
Yamada Hirotake
Burr & Brown
Jones Deborah
NGK Insulators Ltd.
Sperty Arden
LandOfFree
Film of yttria-alumina complex oxide, a method of producing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Film of yttria-alumina complex oxide, a method of producing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Film of yttria-alumina complex oxide, a method of producing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3170677