Etching a substrate: processes – Etching to produce porous or perforated article
Reexamination Certificate
1999-11-12
2001-11-20
Gulakowski, Randy (Department: 1746)
Etching a substrate: processes
Etching to produce porous or perforated article
C216S041000, C216S046000, C216S037000, C216S100000, C216S096000, C156S345420, C204S298110
Reexamination Certificate
active
06319419
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a member and a method of manufacturing a member for a thin-film formation apparatus, and more particularly, the present invention relates to a member and thin-film formation apparatus which, in use, reduces particle production during sputtering processing.
DESCRIPTION OF THE PRIOR ART
In recent years, thin-film formation techniques using vapor-phase growth has been extensively employed for electrodes of integrated circuits, thin films for diffusion barrier, magnetic thin films for magnetic recording media, Indium Tin Oxide (ITO) transparent conductive films of liquids crystals displays, etc. A sputtering method, one of the vapor-phase growth methods, has been widely employed, since it can be applied to a wide range of materials and its film formation control is relatively easy.
This well known sputtering method forms thin films by making charged particles impinge against a sputtering target, expelling the particles of a substance constituting the sputtering target therefrom with the impinging force, and depositing these particles on a substrate such as a wafer placed facing the target.
However, upon formation of thin films by vapor phase growth such as sputtering described above, a problem of particle production has attracted great attention.
These particles will be explained by exemplifying those derived from a target in the sputtering method. When a target is subjected to sputtering, thin films are deposited everywhere, such as, the inner walls of the thin-film formation apparatus, the members inside the apparatus, and on a substrate. Flakes peeling from the members inside the thin-film formation apparatus scatter and are directly deposited on the substrate surface. This is considered to be one of the causes of particle production.
In addition, on the target surface, foreign substances called nodules, which are considered to be produced from flakes peeling from the side surface of the target and the members inside the thin-film formation apparatus, serve as cores and grow to a size of several micrometers in diameter. When these nodules have grown to a certain level, they are broken, scatter, and are deposited on the surface of the substrate. This is also one of the causes of particle production.
When those particles mentioned above are deposited on fine wirings on the substrate, problems such as short-circuiting and, on the contrary, breaking of the wires are caused, for example, in the case of Large Scale Integration (LSI).
In recent years, since LSI semiconductor devices have been highly integrated (16 M bits, 63 M bits, and further 254 M bits, etc.) and have become finer, for example, wiring width (rule) has been reduced to 0.25 &mgr;m or less, the above-mentioned problems such as breaking of wires and short-circuiting have occurred more frequently. Thus, the problem of particle production has become significant as electronic device circuits have become more highly integrated and fine.
As mentioned above, as one of the causes of particle production, a problem of deposition of thin films on the regions, where film formation is essentially not required, of the inner walls of the film formation apparatus or the members inside the apparatus has attracted great attention. Specifically, deposition on peripheral parts of a substrate, shields, backing plates, shutters, targets, and supporting devices thereof can be mentioned.
Since thin films peel from the site, where unnecessary thin films are deposited, and scatter to cause particle production as mentioned above, a technique in which the inner walls of the film formation apparatus, peripheral parts of a substrate, shields, backing plates, shutters, targets and supporting devices thereof are periodically cleaned or exchanged before these deposits become thick and peel has been adopted.
In addition, in order to prevent thin films once deposited from peeling and scattering, at sites of a member (equipment) on which a great amount of thin films are deposited, sprayed metal coatings have been formed (See Japanese Patent Laid-Open Nos. 61-56227 and 8-176816) or deposits have been captured by physical surface roughing treatment such as blast treatment. (See Japanese Patent Laid-Open No. 62-142758).
In addition, since the above-mentioned operations were considered to reduce operation efficiency of thin-film formation, a removable anti-deposition plate to capture deposits was designed in order to prevent deposits from peeling and scattering, and further improvements of the plate were made by changing a thermal expansion coefficient of the plate and by subjecting the plate surface to sand-blast treatment and hair-line treatment. (See Japanese Patent Laid-Open Nos. 63-162861, 2-285067, and 3-138354).
Among these, so-called PARTICLE GETTER (Trade Name) with special surface treatment was epoch-making in efficiently preventing particle production under the technological level of that time. (See Japanese Patent Laid-Open Nos. 1-316456 and 3-87357).
Recently, however, aspect ratios of contact holes and via holes have increased to 3 or more due to a tendency toward fining of wiring rules as mentioned above and it has thus become difficult to fill these holes by conventional sputtering methods. Therefore, highly directional sputtering methods such as collimation sputtering and long-throw have appeared, which require making power twice as large as that required conventionally.
As a result, the density and dispersion of plasma formed during sputtering have been increased so that the surface of shields, collimators, targets, etc., in the vicinity of plasma are simultaneously subjected to sputtering in addition to deposition of thin films.
When the sprayed metal coatings or blast treatment is carried out directly on the inner walls of apparatus or equipment, or anti-deposition plate, as measures to capture the above deposits to prevent their peeling and scattering, the following problems occur: sprayed metal coatings themselves, and residual blast material in the case of blast treatment, are sputtered especially in the early stage of sputtering to contaminate the whole inside of the sputtering apparatus.
Even when the anti-deposition plate was used alone, it had a thickness of its own to limit place for installation. In addition, when sputtering making power was remarkably increased, problems similar to those for sprayed metal coatings and blast-processed material occurred.
As described above, the problem of particle production has not been solved and the measures which have been adopted to prevent particle production, such as sprayed metal coatings and blast treatment, and anti-deposition plates having undergone these processings have themselves caused the serious problem of contaminating thin films.
OBJECTS OF THE INVENTION
Therefore, an object of the present invention is to provide a method of manufacturing a member of a thin-film formation apparatus which efficiently prevents peeling of deposits formed on the surface of the inner walls of the thin-film formation apparatus and members inside the apparatus and suppresses particle production without contaminating the inside of the thin-film formation apparatus.
A further object of the present invention is to provide a member for a thin-film formation apparatus which prevents peeling of deposits from the surface of the member.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a method is provided for manufacturing a member for a thin-film formation apparatus having inner walls. The member and inner walls each have surfaces on which unnecessary thin films are deposited during sputtering. The method includes subjecting at least a portion of the surfaces to masking, and after masking, subjecting the portion of the surfaces to etching processing. The masking is removed after the etching processing so that the surface is provided with an unevenness.
According to another aspect of the present invention, a member is provided for a thin-film formation apparatus. The member comprises a surface having a plurality of concave and
Fukushima Atsushi
Ohhashi Tateo
Takahashi Hideyuki
Gulakowski Randy
Howson and Howson
Japan Energy Corporation
Kornakov Michael
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