Coating apparatus – Gas or vapor deposition – With treating means
Reexamination Certificate
2000-12-07
2004-12-28
Hassanzadeh, P. (Department: 1763)
Coating apparatus
Gas or vapor deposition
With treating means
C118S7230ER, C156S345430
Reexamination Certificate
active
06834613
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plasma-resistant member and also to a plasma-treating apparatus using the same.
2. Description of the Related Art
In a plane-parallel plate-type etching apparatus for etching a silicon oxide film (SiO
2
) or phosphosilicate glass formed on a body to be processed, an etchant gas of a fluorine compound, such as CF
4
, C
2
F
6
, CHF
3
or the like, is used after excitation with a plasma. The fluorine-containing active chemical species generated from these gases corrode Si-based compounds such as silica glass and silicon carbide. To avoid this, anodic oxidized aluminum or alumina ceramics have been used for constituting parts of the etching apparatus used for this purpose. In a step such as of microfabrication or in case where insulating properties are required, more reliable alumina ceramics have been in frequent use.
Alumina ceramics, which are excellent in corrosion resistance against the fluorine plasma used in such an etching apparatus as mentioned above, have been proposed in Japanese Laid-open patent Application Nos. Hei 8-81258 and 8-231266. As the scaling down of a semiconductor integrated circuit is in progress, it is necessary to perform more microfabrication in a higher yield. To meet the necessity, there have been proposed, in place of the parallel-plane type etching apparatus, a variety of low pressure high density plasma. In an apparatus using a microwave as a plasma exciting source, alumina used as a microwave transmitting material has been proposed in Japanese Laid-open Patent Nos. Hei 5-217946 and 6-345527. In these proposals relating to alumina ceramic parts for semiconductor processing apparatus, the purity and grain size of alumina are mainly defined in order to develop a corrosion resistance against the fluorine plasma.
However, as semiconductor devices are scaled down in recent years, there is often required anisotropic etching of a high aspect ratio in an etching process. To meet this requirement, there has now been adopted a method of forming a side wall protecting film so as to suppress the undercut to a minimum and process a deep hole with a small-sized opening.
FIG. 2
principally shows this state as enlarged. In order to form a protecting film on the side walls of an etched deep groove as shown in
FIG. 2
, a polymer film is deposited on the side wall by use of a chlorine-containing gas such as CClF
3
, or a carbon-fluorine-based (C—F based) gas such as C
3
F
8
or C
4
F
8
. The term “polymer” used herein means a fluorocarbon polymer or a fluorocarbon polymer containing alumina fine particles and/or fluorinated alumina product.
When an etching treatment is carried out using such a gas as mentioned above, the polymer of the decomposition product of a reactant gas is deposited on the electrode surface of a reaction chamber, the inner walls of the reaction chamber, a clamp ring, an electrode insulating member and the like, thereby forming a film thereon. When this film gradually becomes thick, it is falls off and is re-deposited on the surface of the semiconductor wafer, thereby lowering its yield. To avoid this, the apparatus (reaction chamber) has to be opened every given period of time in the etching operation and cleaned by removal of the polymer therefrom. This cleaning cycle has been so short as to cause the productivity to be lowered.
The measure against the formation of a polymer in the reaction chamber using the alumina parts has been proposed in Japanese Laid-open Patent Application No. Sho 61-289634. In this application, it is stated to find that the polymer is more unlikely to be formed on an aluminum material in comparison with anodic oxidized aluminum. It is also stated that when using the material, the effect of suppressing the formation of the polymer is obtained even though there is used, aside from C
2
F
6
and CHF
3
, a mixed gas, such as C
3
F
8
and CHF
3
, C
2
F
6
and C
2
H
4
F
2
or the like, as an etchant gas.
However, when we made extensive studies using the parallel-plane-type etching apparatus, it was confirmed that a substantial amount of the polymer was formed on the surface of an alumina ceramic part. From this, it is assumed that the results set out in the Japanese Laid-open Patent Application No. Sho 61-289634 are obtained only under limited conditions.
Japanese Laid-open Patent Application No. Hei 10-32237 proposes a clamp ring, which is made of a porous alumina sintered product having an average grain size of 20 &mgr;m or over. This clamp ring has a greater effect of suppressing a once deposited polymer from falling off than a conventional one. However, this ring is porous, so that there arises the problem that alumina particles may fall off or the ring may be broken owing to its insufficient strength when suffering ionic impact or other mechanical shock at the time of etching.
Especially, the insufficiency of strength presents another problem on the clamp ring when urged against a lower electrode for fixing a body to be processed therewith, or on an electrode insulating member when attached with screws. Moreover, the polymer is deposited in large amounts on a clamp ring, an electrode insulating member, a focus ring, a covering body or the like, located closely to the electrodes, and thus, the falling off or breakaway of the polymer presents a more serious problem.
SUMMARY OF THE INVENTION
An object of the invention is to provide a plasma-resistant member, which does not involve any breakaway of alumina particles and is excellent in mechanical strength, and is able to suppress the breakaway of a once deposited polymer, and also a plasma treating apparatus using the member.
Another object of the invention is to provide a plasma-resistant member, which enables one to prolong an apparatus-cleaning cycle for removal of a deposited polymer, and a plasma-treating apparatus using the member.
The plasma-resistant member of the invention should preferably be used in a reaction chamber of a plasma-treating apparatus. The plasma-resistant member is made of a dense alumina sintered product having an average grain size of 18-45 &mgr;m, a surface roughness Ra of 0.8-3.0 &mgr;m, and a bulk density of 3.90 g/cm
3
or over. It is preferred that the dense alumina sintered product has a purity of not less than 99.8%, an Si content of 200 ppm or below, an alkali metal content of 100 ppm or below.
The plasma treating apparatus comprises an electrode insulating member for electric insulation between at least one of an upper electrode and a lower electrode and a reaction chamber, a clamp ring urging a peripheral portion of a treating surface of a body to be treated against the lower electrode to hold the surface thereat, a focus ring provided in the vicinity of the upper electrode or lower electrode for effectively transmitting reactive ions toward the treating surface of the body to be treated, and a covering member provided to cover the inner walls of the reaction chamber therewith. At least one of the electrode insulating member, the clamp ring, the focus ring and the covering member should be constituted of such a plasma-resistant member.
The plasma treating apparatus may also be arranged to comprise an electrode insulating member for electric insulation between an upper electrode and a reaction chamber, an electrostatic chuck for electrostatically attracting and holding a body to be treated by application of a high voltage to an electric conductor member thereof, a focus ring provided in the vicinity of the upper electrode or lower electrode for effectively transmitting reactive ions toward the treating surface of a body to be treated, and a covering member for covering the inner walls of the reaction chamber. In this arrangement, at least one of the electrode insulating member, the electrostatic chuck, the focus ring and the covering member should be constituted of the plasma-resistant member.
Further, the plasma treating apparatus may be arranged to comprise an electrode insulating member for electric insulation between at least one of an upper electrode
Miyazaki Akira
Morita Keiji
Moriya Shuji
Nagasaka Sachiyuki
Crowell Michelle
Foley & Lardner LLP
Hassanzadeh P.
Toshiba Ceramics Co. Ltd.
LandOfFree
Plasma-resistant member and plasma treatment apparatus using... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plasma-resistant member and plasma treatment apparatus using..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma-resistant member and plasma treatment apparatus using... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3286346