Cleaning and liquid contact with solids – Apparatus – Sequential work treating receptacles or stations with means...
Reexamination Certificate
2000-04-21
2002-12-24
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Sequential work treating receptacles or stations with means...
C134S12200P, C134S902000, C134S184000, C134S186000
Reexamination Certificate
active
06497240
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ultrasonic cleaning device for applying an ultrasonic treatment to a processing target. More specifically, the present invention relates to (1) an ultrasonic cleaning device and method used in a fabrication process of a flat display panel such as a liquid crystal display element or a PDP (plasma display panel) or in a fabrication process of a semiconductor substrate, and (2) a resist-stripping device for stripping and removing a resist by utilizing ultrasonic, for example, a resist-stripping device for stripping and removing a photoresist used in photolithography and the like in a liquid crystal display device fabrication process.
BACKGROUND OF THE INVENTION
A cleaning part of an ultrasonic cleaning device of a conventional single substrate dipping type, that is used in a fabrication process of a flat panel display such as a liquid crystal display element or a PDP or in a fabrication process of a semiconductor substrate is provided with a vibrating element having a vibrating plate or the like, in a lower part of a cleaning bath that reservoirs a cleaning liquid. By operating a stripping element in a state in which a cleaning target such as a substrate is dipped in the cleaning liquid, ultrasonic vibration is applied to the cleaning liquid, so that the cleaning target is subjected to the ultrasonic cleaning treatment.
The foregoing ultrasonic cleaning device, however, requires a large quantity of a cleaning liquid. Besides, since the cleaning liquid in the cleaning bath is replaced regularly at predetermined intervals, there is possibility that the cleaning of a target would be insufficient. Furthermore, upon the cleaning treatment, transport of a target has to be suspended while the target is dipped into the cleaning liquid, thereby causing a longer time to be spent for the treatment.
On the other hand, the cleaning part of the ultrasonic cleaning device of a conventional single substrate type in which a cleaning liquid is supplied to a cleaning target by means of an ultrasonic cleaning nozzle is provided with an ultrasonic cleaning nozzle
102
, above a substrate
101
that is the cleaning target, as shown in
FIG. 10. A
cleaning liquid (pure water, in the most cases)
103
to which ultrasonic has been projected (applied) is sprayed over an upper surface of the substrate
101
, which is transported while being horizontally kept. In so doing, particles of organic materials, metallic materials, etc. adhering to the substrate
101
are removed, so that the surface is cleaned. Besides, the vibrating element for generating the ultrasonic to be projected to the cleaning liquid is usually provided inside the ultrasonic cleaning nozzle
102
, or occasionally in a cleaning-liquid-supply pipe that connects the ultrasonic cleaning nozzle
102
with a cleaning-liquid-supply pump provided on an upstream side to the ultrasonic cleaning nozzle
102
.
Usually applied as a method for spraying the cleaning liquid
103
is a showering method in which the cleaning liquid
103
is sprayed in a shower form with a width equal to or broader than that of the substrate
101
while ultrasonic is projected to the cleaning liquid
103
by the vibrating element.
According to the foregoing arrangement, the cleaning treatment of the substrate
101
is carried out always with the fresh cleaning liquid
103
(in the case where the cleaning liquid
103
is not collected and reused). Besides, the cleaning treatment to the substrate
101
can be carried out while the substrate
101
is being transported by transport rollers (not show) or the like.
Incidentally, the foregoing vibrating element is damaged or broken within a short period of time due to heat unless it is operated in a liquid having no bubbles. Therefore, when generating the ultrasonic, the vibrating element need be sufficiently surrounded by a liquid such as the cleaning liquid
103
.
The aforementioned conventional ultrasonic cleaning device, however, has a nozzle opening
102
a
facing downwards above the substrate
101
as the cleaning target, and is arranged so that the cleaning liquid
103
is jetted downwards through the nozzle opening
102
a
. Therefore, bubbles likely intrude therein through the nozzle opening
102
a
. Besides, the distribution path of the cleaning liquid
103
(more specifically, the ultrasonic cleaning nozzle
102
, the cleaning-liquid-supply pipe, the cleaning-liquid-supply pump, etc.) extends downwards or diagonally downwards, and bubbles generated upon operation of the vibrating element provided in the distribution path (more specifically, inside the ultrasonic cleaning nozzle
102
) tend to remain therearound. Moreover, the bubbles having intruded therein are hardly discharged to outside the distribution path of the cleaning liquid
103
.
Therefore, to flow the cleaning liquid
103
so as to prevent bubbles from remaining around the vibrating element, a complex structure is required, which is characterized as follows, for instance: (1) a plurality of cleaning liquid distribution paths are provided inside the ultrasonic cleaning nozzle
102
; and (2) the inside wall of the ultrasonic cleaning nozzle
102
is formed in a tapered shape. Besides, to discharge bubbles through the nozzle opening
102
a
, it is necessary to flow a great quantity of the cleaning liquid
103
at all times, with the opening area of the nozzle opening
102
a
and the like taken into consideration. These problems have become severer as the substrate (cleaning target: processing target)
101
becomes larger in size. Furthermore, in the case of the above-described conventional ultrasonic cleaning device, to clean both the surfaces of the substrate
101
simultaneously is impossible, although to flow a great quantity of the cleaning liquid
103
is required.
Besides, the resist stripping treatment for stripping the resist applied on the substrate is either (1) a batch type in which a plurality of substrates are simultaneously subjected to the resist stripping treatment, or (2) a single substrate type in which the substrates are subjected to the resist stripping treatment one by one. The batch type, processing a plurality of substrates simultaneously, has an advantage of a higher processing capacity. As the substrate treated becomes larger in size, however, a quantity of an organic solvent or the like reservoired as a resist stripper in a stripping treatment bath increases. Thus, there are also problems regarding safety.
On the other hand, methods for the resist stripping treatment of the single substrate type include, generally, (1) a dipping method in which a substrate is dipped in a stripping treatment bath reservoiring a resist stripper, (2) a showering method in which a resist-applied surface of a substrate is sprayed with a resist stripper, and (3) a method in which the methods of the foregoing two types are used in combination. In some arrangements for the dipping method, an ultrasonic vibrating plate is provided at the bottom of the stripping treatment bath.
The single-substrate-type method is advantageous, particularly for a large substrate with a diagonal of not less than 1 m, in that a quantity of an organic solvent used is smaller as compared with that in the case of the foregoing batch type since the substrates are treated one by one. The time spent in the resist stripping treatment, however, becomes a rate-limiting factor, and therefore, the processing capacity of the single-substrate-type method is generally smaller than that of the batch-type method.
To improve the processing capacity of a device of the single substrate type, a processing chamber for stripping resist (stripping section) may be designed long, for example. Designing the processing chamber long, however, leads to problems of causing a device footprint larger and of increasing an organic solvent used, thereby impairing the advantage of the single substrate type. In the case of an arrangement for the dipping method, an ultrasonic vibrating plate is provided at the bottom of a stripping treatment bath, improvement
Kobayashi Kazuki
Muratani Toshiaki
Yoshioka Hiroto
Conlin David G.
Dike Bronstein, Roberts & Cushman IP Group, Edwards & Angell, LL
Hartnell, III George W.
Sharp Kabushiki Kaisha
Stinson Frankie L.
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