Cleaning and liquid contact with solids – Apparatus – With means to movably mount or movably support the work or...
Reexamination Certificate
2000-02-04
2003-04-01
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
With means to movably mount or movably support the work or...
C134S001000, C134S001300, C134S902000
Reexamination Certificate
active
06539959
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cleaning apparatus for a plate-like part which cleans a thin plate-like part such as a semiconductor wafer, a magnetic recording disc medium, a liquid crystal display panel, a Braun tube shadow mask and the like, and a method thereof.
Further, the present invention relates to a fluid treatment method for a substrate and a treating apparatus therefor, and particularly to a fluid treatment method for a substrate which is preferable for fluid treating a plate-like material such as a semiconductor wafer, a liquid crystal substrate, a magnetic disc and the like corresponding to a substrate to be treated in accordance with a single wafer method, and a treating apparatus therefor.
2. Description of the Prior Art
Conventionally, as a structure which cleans the plate-like part such as a silicon wafer and the like, for example, there is known a structure which is disclosed in Japanese Patent Unexamined Publication No. 8-130202 (a first prior art).
The cleaning apparatus described in the first prior art is provided with an upper cleaning plate which is opposed to an upper surface of the wafer, a lower cleaning plate which is opposed to a lower surface of the wafer, and a cylindrical wafer holding device which has an inner diameter coinciding with an outer diameter of the wafer. The wafer is held in a horizontal state, in a state that an outer periphery of the wafer is in contact with an inner peripheral surface of the wafer holding device. The upper cleaning plate and the lower cleaning plate are respectively arranged in parallel to the upper surface and the lower surface of the wafer, and injects a cleaning fluid to the upper surface and the lower surface of the wafer. At this time, the wafer holding device is rotated and the wafer held thereto is also rotated.
The cleaning fluid injected from a center of the upper cleaning plate is flown out from a portion between an outer peripheral edge of the upper cleaning plate and an outer peripheral edge of the upper surface of the wafer through a portion between the upper cleaning plate and the upper surface of the wafer. Further, the cleaning fluid injected from a center of the lower cleaning plate is flown out from a portion between an outer peripheral edge of the lower cleaning plate and an outer peripheral edge of the lower surface of the wafer through a portion between the lower cleaning plate and the lower surface of the wafer. A pressure in accordance with a Bernoulli's theorem is respectively generated between the upper cleaning plate and the upper surface of the wafer and between the lower cleaning plate and the lower surface of the wafer, by the cleaning fluid which respectively flows therethrough. At a time of rinsing the wafer, a delicate pressure balance is kept between the upper cleaning plate and the upper surface of the wafer and between the lower cleaning plate and the lower surface of the wafer.
However, the first prior art mentioned above takes into consideration a problem that in the case of setting an interval between the upper cleaning plate and the upper surface of the wafer and an interval between the lower cleaning plate and the lower surface of the wafer to an interval which is enough narrow to obtain an effect of improving a cleaning capacity, the wafer and the cleaning plate relatively move in a rinsing and drying step corresponding to the latter half of the wafer rinsing, whereby a static electricity is charged between the both and unnecessary reaction, contamination and damage are generated on the wafer surface.
That is, in the first prior art, since no attention is paid to the generation of the static electricity mentioned above, it is hard to avoid the unnecessary reaction, contamination and damage in the cleaning and drying process. Even in the case that a distance between the cleaning plate and the wafer is increased so as to reduce a flow speed of the fluid and reduce the generated static electricity, thereby reducing a transmission of an ionized ion due to the widened distance so as to reduce a charged amount, it is impossible to achieve a fundamental solution, and it is impossible to expect an effect of improving the cleaning capacity due to employment of the cleaning plate.
On the contrary, in the case of treating the plate-like part by using the narrow space for cleaning and drying, as is executed in the conventional spin cleaning apparatus, there is a method of introducing a gas such as a nitrogen and the like which is charged with positive or negative electricity so as to neutralize the charged electricity, however, this method has a little effect. Because in accordance with the method of employing the charged gas, the gas charging with an opposite polarity to that of the member charging with the static electricity is attracted to the member, thereby neutralizing the charged electricity, however, when introducing the gas charging with the positive or negative electricity to the narrow space, the gas is rapidly mixed with itself and neutralizes itself, so that the effect of neutralizing the charged electricity of the plate-like part corresponding to the subject to be cleaned is rapidly removed. Accordingly, the effect is restrictedly obtained near the pole of the gas supply portion.
Further, as the conventional fluid treating apparatus for the semiconductor substrate and the like in accordance with the single wafer method, there is known a cleaning apparatus which irradiates a treating fluid such as a liquid or a gas toward a substrate while rotating the substrate (for example, Japanese Patent Unexamined Publication No. 4-287922). In the case of performing a cleaning process, a rinsing process and a drying process in this order, the process is performed by subsequently irradiating a cleaning fluid from a first nozzle, a rinsing fluid from a second nozzle and a nitrogen from a third nozzle, toward the substrate while rotating the substrate.
In the case of irradiating the cleaning fluid or the rinsing fluid so as to rotate the substrate, the cleaning fluid or the rinsing fluid is attached to the inner wall of the treating tank. Since the substrate is rotated at a high speed in the drying process, a downward air current toward the substrate is generated together with the rotation and a vortex air current is generated within the treating tank. The cleaning fluid or the rinsing fluid attached to the inner wall of the treating tank is carried on the vortex air current, is attached to the surface of the substrate and causes a recontamination.
As a method of preventing a recontamination to the substrate mentioned above, there is a method of placing a plate opposite to the substrate, for example, there is known a cleaning apparatus disclosed in Japanese Patent Unexamined Publication Nos. 8-130202 and 8-78368. These are structured such that the process is performed by gripping the substrate from upper and lower portions by the cleaning plate and subsequently supplying the cleaning fluid, the rinsing fluid or the nitrogen gas from a center portion, and since it is possible to prevent the air current toward the substrate by the cleaning plate even in the case of high speed rotation, it is possible to prevent the recontamination onto the surface of the substrate.
For example, in a step for restricting a growth of a natural oxidation film such as a step prior to a gate oxidation film forming step of a semiconductor manufacturing step or the like, it is necessary to control an atmosphere after cleaning to a high level for restricting oxidation. In a conventional apparatus having a wide treatment space, since a lot of time is required for replacing the atmosphere, it is necessary to reduce the treatment space as much as possible. Further, it is also possible to reduce an amount of consumption of the treating fluid by making the treatment space small.
However, in the case of performing a drying process by setting an interval between a cleaning plate
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and a substrate to be treated 8 to 0.6 mm to 1.0 mm with using an apparatus
Aiuchi Susumu
Fujiki Masataka
Morita Fumio
Ohroku Noriyuki
Oka Hitoshi
Antonelli Terry Stout & Kraus LLP
Markoff Alexander
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