Brushing – scrubbing – and general cleaning – Machines – Wiping
Reexamination Certificate
1999-12-08
2002-07-02
Spisich, Mark (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
Wiping
C015S097100, C015S230000, C015S230160, C015S230170, C015S230190, C015S244100
Reexamination Certificate
active
06412134
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning device for use in a cleaning apparatus in which a cleaning fluid is supplied onto a substrate to be cleaned, e.g. a semiconductor wafer, which is being rotated in a horizontal position, and while doing so, the substrate is cleaned with the cleaning device. The present invention also relates to a substrate cleaning apparatus using the above-described cleaning device.
A conventional cleaning device of the type described above has a structure shown in FIG.
1
. The cleaning device, as shown in
FIG. 1
, includes a disk-shaped sponge member
101
, which is a cleaning member, and a cleaning member holding mechanism
102
for holding the sponge member
101
. The cleaning member holding mechanism
102
includes a columnar holder body
103
having a frusto-conical portion at the lower end thereof and a collar portion at the upper end thereof. The cleaning member holding mechanism
102
further includes a ring member
104
fitted on the outer peripheral portion of the holder body
103
. The lower end portion of the ring member
104
is drawn so as to form a predetermined gap between itself and the outer periphery of the frusto-conical portion of the holder body
103
.
With the sponge member
101
placed in abutment on the frusto-conical portion of the holder body
103
, the ring member
104
is fitted onto the outer peripheral portion of the holder body
103
, thereby holding the sponge member
101
between the outer periphery of the holder body
103
and the inner periphery of the ring member
104
. Thus, the sponge member
101
is fitted in the cleaning member holding mechanism
102
. The holder body
103
is provided with a tapped hole
106
for threaded engagement with the distal end of a rotating shaft for holding and rotating the cleaning device. The holder body
103
and the ring member
104
are secured to each other with a screw
105
. However, the cleaning device having the above-described structure suffers from some problems as stated below.
{circle around (1)} Because the sponge member
101
is held between the holder body
103
and the ring member
104
, a jig is needed to correctly fit the sponge member
101
into the cleaning member holding mechanism
102
, and some experience is required to carry out the fitting operation.
{circle around (2)} As shown in FIG.
5
(
a
), the sponge member
101
and the cleaning member holding mechanism
102
are moved in approximately the diametrical direction of a substrate Wf to be cleaned with the sponge member
101
placed in contact with the rotating substrate Wf within a range in which there is no interference between a projection (chuck)
111
of a substrate holding and rotating mechanism for holding and rotating the substrate Wf and either of the cleaning member holding mechanism
102
and the sponge member
101
. When the cleaning member holding mechanism
102
and the sponge member
101
are moved in this way, a contact surface of the sponge member
101
that comes in contact with the substrate Wf is unable to sufficiently cover the edge portion Wfa. Consequently, the range of cleaning does not extend to the edge portion Wfa. In other words, the radius R1 of the cleaning range of the cleaning device is small, and the edge portion E1 of the substrate Wf left uncleaned is undesirably large in area.
{circle around (3)} The corner of the substrate contacting surface of the sponge member
101
is rounded. Accordingly, the area (outer diameter) of contact of the sponge member
101
with the substrate Wf readily changes with variations in pressure with which the sponge member
101
is pressed against the substrate Wf. Thus, variations in pressure applied to the sponge member
101
cause the cleaning range to change undesirably.
FIG. 2
shows the structure of another conventional cleaning device of the type described above. As shown in
FIG. 2
, the cleaning device includes a stepped columnar sponge member
201
having an upper portion with a larger outer diameter than that of a lower portion thereof. The cleaning device further includes a cleaning member holding mechanism
202
for holding the sponge member
201
. The cleaning member holding mechanism
202
includes a stepped columnar holder body
203
having an upper portion with a larger outer diameter than that of a lower portion thereof. The cleaning member holding mechanism
202
further includes a ring member
204
that is brought into threaded engagement with the outer periphery of the lower portion of the holder body
203
. The ring member
204
has a projection
204
a
projecting inward from the distal end thereof.
With the sponge member
201
placed in abutment against the holder body
203
, the ring member
204
is brought into threaded engagement with the outer periphery of the lower portion of the holder body
203
. Consequently, the projection
204
a
of the ring member
204
abuts against the step portion of the sponge member
201
, and thus the upper portion of the sponge member
201
is held between the projection
204
a
and the holder body
203
. In this way, the sponge member
201
is fitted in the cleaning member holding mechanism
202
. The holder body
203
is formed with a tapped hole
205
for threaded engagement with the distal end of a rotating shaft for holding and rotating the cleaning device. The cleaning device having the above-described structure involves some problems as stated below.
{circle around (1)} Because the ring member
204
is connected to the holder body
203
by threaded engagement, it takes a great deal of time and labor to loosen or tighten the ring member
204
when the sponge member
201
is to be detached or attached.
{circle around (2)} In use, a sponge swells with cleaning water or the like and slightly increases in volume. In this regard, the sponge member
201
is held by the holder body
203
and the ring member
204
in the cleaning device having the structure shown in FIG.
2
. Therefore, expansion occurs markedly at the substrate contacting surface of the sponge member
201
, and the sponge member
201
tends to swell convexly at the center of the substrate contacting surface (as shown by the chain double-dashed line in FIG.
2
). This may cause damage to the surface of a film formed on the surface of the substrate to be cleaned, depending on the kind of film.
{circle around (3)} Unlike the cleaning member shown in
FIG. 1
, the sponge member
201
of the cleaning device shown in
FIG. 2
is shaped such that the outer peripheral portion thereof forms right angles to the lower surface thereof (i.e. the corner is not rounded). Therefore, the area of contact of the sponge member
201
with the substrate to be cleaned seems to be wide. However, in the case of the cleaning device shown in
FIG. 2
, the amount L that the sponge member
201
projects from the lower end of the ring member
204
needs to be large in order to avoid interference between the cleaning member holding mechanism
202
and a chuck (not shown). Accordingly, when moved toward the outer periphery of the substrate, the sponge member
201
is deformed toward the center of the substrate as shown by the one-dot chain line in FIG.
2
. In actuality, the outer diameter of contact of the sponge member
201
becomes small at the outer peripheral portion of the substrate. Therefore, the outer peripheral portion of the substrate is likely to be left uncleaned. Moreover, the deformation of the sponge member
201
causes variations (reduction) in the contact pressure of the sponge member
201
with respect to the substrate.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, an object of the present invention is to provide a cleaning device designed so that a cleaning member, e.g. a sponge, which comes into contact with a substrate to be cleaned, is easy to fit to the cleaning device, and even when the cleaning member is deformed, the substrate can be cleaned right up to the edge, and further that the area of contact with the substrate is unlikely to change with variations in pressure w
Ebara Corporation
Spisich Mark
Wenderoth , Lind & Ponack, L.L.P.
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