Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
1998-12-03
2001-07-03
Carillo, Sharidan (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S002000, C134S006000, C134S009000, C134S015000, C134S025400, C134S032000, C134S042000, C134S902000, C015S021100, C015S077000, C015S088200, C015S088300, C015S097100
Reexamination Certificate
active
06254688
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for cleaning an object such as a wafer using a brush.
2. Description of the Related Art
Manufacturing steps of a semiconductor or a thin-film head include a wafer cleaning step for removing contaminants on a wafer surface as necessary. Such wafer cleaning methods include scrub cleaning. Scrub cleaning is a method of removing deposits on a surface of an object such as a wafer by scrubbing the surface by a brush, applying the rotating brush to the object surface with a cleaning liquid.
Referring to
FIG. 12
, an example of a scrub cleaning process of related art will now be described. As shown, a wafer
111
as an object to clean is taken out of a loader bath
101
and supplied to a scrub cleaning apparatus
102
.
FIG. 13
is a schematic front view of the scrub cleaning apparatus
102
.
FIG. 14
is a schematic side view of the scrub cleaning apparatus
102
. As shown, the scrub cleaning apparatus
102
comprises: a rotating table (not shown); a cylindrical rotating brush
112
placed on the rotating table; and a cleaning liquid ejector
113
placed above the rotating brush
112
and having a plurality of cleaning liquid outlets arranged along the axial direction of the brush
112
. For cleaning of the wafer
111
by the scrub cleaning apparatus
102
, the wafer
111
is fixed on the rotating table. The rotating brush
112
is positioned so as to touch the surface of the wafer
111
. A cleaning liquid
114
is ejected like a shower through the outlets of the cleaning liquid ejector
113
towards the rotating brush
112
and the wafer
111
. In this state the wafer
111
is rotated by the rotating table and the rotating brush
112
is rotated. The surface of the wafer
111
is thereby cleaned. The cleaning liquid
114
is detergent or ultrapure water.
Next, as shown in
FIG. 12
, the wafer
111
is taken out of the scrub cleaning apparatus
102
and transferred to a spin dryer
103
where a rinse step is performed by megasonic rinse. The wafer
111
is then dried by the spin dryer
103
. The wafer
111
is taken out of the spin dyer
103
and placed in a carrier
104
by an unloader.
Cleaning while applying a cleaning liquid in a spray to the rotating brush
112
has been generally performed as a scrub cleaning method of related art as described above. Another cleaning method is cleaning with an application of ultrasonic vibrations to cleaning water in a spray.
As disclosed in Japanese Patent Application Laid-open Hei 7-86218 (1995), another scrub cleaning method of related art is performing brush (scrub) cleaning and ultrasonic cleaning at the same time. That is, a cleaning apparatus having a cleaner with a desk-shaped brush and a cleaning liquid ejector placed near the brush is used. An object to clean is scrubbed with the brush while a cleaning liquid to which ultrasonic vibrations are applied is ejected through the cleaning liquid ejector.
In the related-art cleaning method described with reference to
FIG. 12
to FIG.
14
and in the other related-art method disclosed in the above-mentioned publication, however, a very small portion of cleaning liquid layer is only formed on the object surface. Consequently, particles of contaminants removed from the object and abrasion residues of the brush are likely to be taken in the cleaning liquid on the object surface and to redeposit on the surface.
In the related-art method, a very small portion of cleaning liquid layer is only formed on the object surface as well when ultrasonic cleaning is performed at the same time by applying ultrasonic vibrations to the cleaning liquid. It is therefore difficult to achieve effects of ultrasonic cleaning as expected.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a cleaning method and apparatus for preventing removed contaminants and abrasion residues of a brush from redepositing on an object to clean.
It is a second object of the invention to provide a cleaning method and apparatus for efficiently and effectively performing scrub cleaning and ultrasonic cleaning, in addition to the first object.
A cleaning method of the invention includes the steps of: having a cleaning liquid contained in a container for containing the cleaning liquid; retaining an object to clean in the cleaning liquid contained in the container; and cleaning the retained object by scrubbing with a brush in the cleaning liquid contained in the container.
In the method, the object is retained in the cleaning liquid contained in the container and cleaned through scrubbing with the brush.
In the cleaning method, it is preferred that ultrasonic vibrations are applied to the cleaning liquid contained in the container. Scrub cleaning with the brush and ultrasonic cleaning by ultrasonic vibrations are thereby performed on the object in the cleaning liquid contained in the container. In the method, it is preferred that a position of the object is shifted in the cleaning liquid contained in the container.
In the method, it is preferred that an additional cleaning liquid is supplied to the container while the cleaning liquid is discharged from the container. The object cleaned in the method may be an intermediate product on which mechanical flattening is performed in a manufacturing process of a device having a plurality of layers.
A cleaning apparatus of the invention comprises: a container for containing a cleaning liquid; a means or device for retaining an object to clean in the cleaning liquid contained in the container; and a brush for cleaning the object retained by the means or device for retaining by scrubbing the object in the cleaning liquid contained in the container.
In the apparatus, the object is retained by the means or device for retaining in the cleaning liquid contained in the container and cleaned through scrubbing with the brush.
The cleaning apparatus preferably further comprises a means or device for applying ultrasonic vibrations to the cleaning liquid contained in the container. Scrub cleaning with the brush and ultrasonic cleaning by ultrasonic vibrations applied to the cleaning liquid by the means or device for applying are thereby performed on the object in the cleaning liquid contained in the container. In the cleaning apparatus the means or device for retaining preferably includes a means or device for shifting a position of the object in the cleaning liquid contained in the container.
The cleaning apparatus preferably further comprises a means or device for supplying an additional cleaning liquid to the container while discharging the cleaning liquid contained in the container. The object cleaned by the apparatus may be an intermediate product on which mechanical flattening is performed in a manufacturing process of a device having a plurality of layers.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
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English-language abstract of SU 1458032 A; Feb. 15, 1989.
Kobayashi Kanji
Kudo Jun
Yamaguchi Masao
Yoshihara Shinya
Carillo Sharidan
Oliff & Berridg,e PLC
TDK Corporation
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