Gas and liquid contact apparatus – Fluid distribution – Valved
Reexamination Certificate
2000-06-30
2001-12-04
Bushey, C. Scott (Department: 1724)
Gas and liquid contact apparatus
Fluid distribution
Valved
C261S062000, C261S064100, C261S105000, C261SDIG004
Reexamination Certificate
active
06325359
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device and method for producing gas solution, such as hydrogen solution, ozone solution, or the like, for preferable use in cleaning of substrates or the like used in production of electronic components and other such devices, and also to a cleaning device employing the gas solution producing device.
2. Description of the Related Art
In the field of electronic devices (semiconductor devices, LCD panels, and so on), a step of cleaning substrates (semiconductor or glass substrates, and so on) is included in all production process. During cleaning, foreign objects, including organic material (e.g., particles, photoresists, and so on) in the atmosphere in a clean room, which have become attached to the substrates must be removed. There is therefore great interest in cleaning solutions superior in cleaning performance and preferable for use in such cleaning. Some candidates of such solution are ozone solution and hydrogen solution, and so on, which can be obtained by dissolving gas (ozone, hydrogen, and so on) in deionized water. As a method for dissolving these gases into deionized water, a method for bringing gas into contact with deionized water via hollow fiber membrane is well known conventionally.
FIG. 13
is a diagram showing a conventional ozone solution producing device
90
. The ozone solution producing device
90
mainly comprises an ozone producing device
91
and a gas dissolving module
92
. The gas dissolving module
92
is, for example, a cylinder vessel accommodating a number of hollow fiber membranes, and supplied with ozone gas produced in the ozone producing device
91
, as well as deionized water. When ozone gas and deionized water are introduced into the gas dissolving module
92
, the ozone gas flows into each hollow fiber membrane, while the deionized water fills interior space of the vessel. Then, when the ozone gas and deionized water come into contact with each other via the hollow fiber membranes, the ozone gas is dissolved into the deionized water and an ozone solution consisting of ozone dissolved in deionized water is produced. The resultant ozone solution is supplied to, for example, a nozzle
93
of a cleaning device, for use in cleaning.
The above-mentioned conventional ozone solution producing device, however, has the following shortcomings. The conventional electrolytic ozone producing device for general use is constructed, for protection of the electrodes, such that ozone production cannot be suspended. Moreover, as the starting up of a gas dissolving module requires a relatively longer period of time, ozone production must be continued to ensure stable ozone concentration. Thus, there is no choice but to discard unused ozone solution. In addition, as the ozone producing device and the gas dissolving module are directly connected to each other via a pipe, ozone gas is always supplied to the gas dissolving module whether or not ozone solution is used. In other words, while ozone solution is not used, ozone gas is wastefully thrown away. This results in a very inefficient device.
In order to improve the efficiency of such equipment, there has been proposed a structure in which a valve is provided in a pipe connecting the ozone producing device and the gas dissolving module. With this structure, the valve is closed while ozone solution is not used, to thereby stop supply of ozone gas. As a result, waste of ozone gas can be prevented. However, generally, as the total capacity of the hollow fiber membranes in an ozone solution producing equipment is relatively large compared to the amount of ozone gas produced, a relatively long time is required before the ozone gas concentration in the hollow fiber membranes becomes stabilized in a normal condition after supply of ozone gas is resumed. This results in a long time before ozone concentration of the ozone solution reaches a predetermined value, or a long start-up time, and thus an equipment of a reduced operation rate.
On the other hand, where ozone solution may be needed quickly for cleaning, a constant supply of ozone gas to the gas dissolving module must be maintained. Not only may this result in a waste of ozone gas, provision of the valve becomes meaningless.
In addition, components of the above-mentioned equipment, including pipes, must be highly pressure resistive as pressure increases on the ozone producing device side when the valve is closed, particularly, for a long time.
SUMMARY OF THE INVENTION
The present invention has been conceived to remedy the aforementioned shortcomings and aims to provide a device for producing gas solution, having a simple structure to reduce start-up time, and capable of reducing the amount of gas or solvent in use, and a method therefor, as well as a cleaning device employing the device and method.
In order to achieve the above object, according to the present invention, there is provided a gas solution producing device. The device comprises gas dissolving means for receiving gas and solvent as material of gas solution and bringing the gas and the solvent to contact to each other to thereby dissolve the gas into the solvent; a gas introducing path for introducing the gas from a gas supply source to the gas dissolving means; gas storing means, provided on the gas introducing path, for temporarily storing the gas, and, after having stored a predetermined amount of gas, for discharging the gas stored to the gas introducing path; switching means, provided at a connection between the gas introducing path and the gas storing means or a position on the gas introducing path closer to the gas dissolving means than the connection, for switching introduction and suspension of the gas flowing into the gas dissolving means by opening or closing the gas introducing path; and stored gas backflow prevention means, provided at the connection between the gas introducing path and the gas storing means or a position on the gas introducing path closer to the gas supply source, for preventing the gas discharged from the gas storing means from backflowing to the gas supply source side.
Further, according to the present invention, there is provided a method for producing gas solution using the above described gas solution producing device. The method comprises the steps of temporarily storing a predetermined amount of gas in the gas storing means while introduction of the gas from the gas supply source to the gas dissolving means is suspended by the switching means closing the gas introducing path;discharging, thereafter, the gas stored in the gas storing means to the gas dissolving means by the switching means opening the gas introducing path; and dissolving the gas into the solvent in the gas dissolving means by bringing the gas and the solvent into contact with each other.
A gas solution producing device of the present invention as described above comprises gas storing means, provided on the way of a gas introducing path connecting the gas supply source and the gas dissolving means, switching means, provided on a position on the gas introducing path closer to the gas dissolving means than a connection between the gas introducing path and the gas storing means, and stored gas black-flow preventing means, provide on a position on the gas introducing path closer to the gas supply source than the connection between the gas introducing path and the gas storing means.
With this arrangement, gas from the gas supply source is introduced into the gas storing means for temporal storage therein while gas introduction to the gas dissolving means is suspended by the switching means closing the gas introducing path. Thereafter, the gas introducing path is opened, whereby the gas temporarily stored in the gas storing means is discharged toward the gas dissolving means. During discharge, because stored gas backflow prevention means is provided to the gas solution producing device, the discharged gas does not flow back to the gas supply source, and is reliably introduced to the gas dissolving means side. When th
Haga Nobuaki
Kasama Yasuhiko
Mitsumori Ken'ichi
Bushey C. Scott
Organo Corporation
Rosenthal & Osha LLP
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