JPH0587283B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for filtering liquids such as resist liquid, resist thinner, resist developer, etching liquid, and rinsing liquid for semiconductor manufacturing.

[Conventional technology]

In general, before the resist solution is stored in a resist solution dropping device that drops the resist solution onto a desired article, for example, a photomask blank, after obtaining the resist solution, gel-like substances of the resist solution mixed in the resist solution are prepared. It must be filtered to remove foreign matter and other foreign matter. However, one-time filtration cannot completely remove gel-like substances and other foreign substances from the resist solution, and there is a possibility that foreign substances attached to the filter itself may be taken in by the resist solution after filtration, which may affect the removal efficiency. In order to increase the resistance and obtain a clean resist solution, repeated filtration is necessary.

FIG. 3 shows a conventional example of this type of filtration device, which includes a first container 2 containing a resist liquid 1 to be filtered, a pressurizer 3 containing this first container 2, and a pressurizer 3 containing the first container 2. a pipe 4 for supplying an inert gas such as _N2 into the pressurizer 3 to pressurize the resist solution 1 in the first container 2;
The resist liquid 1 is composed of a pipe 6 for transferring the resist liquid 1 to a second container 5, and a filter 7 interposed in the middle of the pipe 6 for filtering the resist liquid 1.

When filtering the resist liquid 1, an inert gas is continuously introduced into the pressurizer 3 through the pipe 4, and the pressure inside the pressurizer 3 is made higher than atmospheric pressure. Then,
Due to this pressure, the resist liquid 1 in the first container 2 is transferred to the second container 5 through the pipe 6, and is filtered by a filter 7 along the way. Then, when almost the entire amount of the resist liquid 1 is transferred into the pipe 6, the supply of inert gas is stopped, and the first filtration of the resist liquid 1 is completed. Next, in order to perform a second filtration, the resist liquid 1 contained in the second container 5 is transferred to the empty first container 2. Thereafter, the same operation as above is repeated to perform filtration.

[Problem that the invention seeks to solve]

However, in the conventional filtration device, each time filtration is repeated, the resist solution 1 stored in the second container 5 must be transferred to the empty first container 2, which is a troublesome and troublesome operation. There was an inconvenience that it was. Moreover, since it is necessary to remove the first container 2 from the pressurizer 3 when transferring,
Particularly, the end of the piping 6 on the side of the first container 2 may come into contact with objects other than the resist liquid 1 and become contaminated, or air may enter the piping 6. During the next filtration, part of this air enters the filter 7, and the rest mixes into the resist liquid 1 as fine bubbles and passes through the filter 7. Therefore, the air remaining in the filter 7 dries the resist liquid 1 adhering to the filter 7, and as a result, gel-like foreign matter is formed and adhered thereto, making it impossible to function as a filter. Further, when a resist film is formed using the resist solution 1 containing bubbles, there is a drawback that a good quality resist film cannot be obtained due to the bubbles.

As described above, in the conventional apparatus, there is a high possibility that the resist liquid 1 that has been filtered once is also contaminated, and the effect of repeated filtration is impaired.

[Means for solving problems]

The filtration device according to the present invention has been made to solve the above-mentioned problems, and its first purpose is to provide a device that continuously performs repeated filtration, and its second purpose is to solve the above-mentioned problems. An object of the present invention is to provide a device that automatically performs continuous filtration.

In order to achieve the first object, the filtration device according to the present invention comprises first and second containers containing a liquid to be filtered, and transferring the liquid from the first container to the second container and vice versa. means for filtering the liquid, and a third container that ultimately stores the liquid filtered by the filtering means,
A first valve is provided in a flow path connecting the first container and the second container to control the liquid transferred from these containers to the filtration means, and the liquid discharged from the filtration means is the third container and the third
a second valve for selectively controlling the flow to the valve;
The liquid transferred to the third valve is controlled to be selectively sent to the first and second containers by the valve.

In addition, in order to achieve the second object, a filtration device according to another aspect of the present invention includes first and second containers for storing a liquid to be filtered, and for transferring the liquid from the first container to the second container. a means for transferring the liquid in the opposite direction; a means for filtering the liquid; and a third container that ultimately stores the liquid filtered by the filtration means; A first valve for controlling the liquid transferred from these containers to be sent to the filtration means is provided in a flow path connecting the containers, and the liquid discharged from the filtration means is connected to the third container and the third valve. a second valve controlled to selectively send the liquid to the first and second containers; further controlling the liquid transferred to the third valve to be selectively sent to the first and second containers; A weight measuring device is provided below the first container or the second container, and upon receiving instructions from the weight measuring device, the liquid transfer operation is controlled and the flow paths of the first, second and third valves are controlled. It is equipped with a control device that switches between the two.

[Effect]

In the present invention, since there is no need to manually transfer the liquid each time, repeated filtration can be performed continuously, thereby preventing contamination of piping, mixing of air, etc. Furthermore, since continuous filtration is performed automatically, handling is easy and labor-saving is possible.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing a first embodiment of a filtration device according to the present invention.

In this embodiment, first and second containers 2 and 5 containing a resist solution 1 (e.g., positive resist MP-1350 (trade name, Shupley Co., Ltd.)
First and second pressurizers 3 and 10 accommodate containers 2 and 5, respectively, and an inert gas ( A first gas introduction pipe 4 for supplying (for example, _N2 gas) and a resist liquid 1 in a second container 5.
A second gas introduction pipe 1 for supplying an inert gas (for example, N ₂ gas) into the second pressurizer 10 in order to transfer the gas to the first container 2 or a third container 13 to be described later.
2, a filter 7 made of tetrafluoroethylene resin for filtering the resist solution 1 (e.g., a membrane filter, manufactured by Nippon Millibore Ltd., Flolex), and the filtered resist solution 1.
a third container 13 that finally accommodates the first,
Piping 15, 16, 17 connecting the second and third containers 2, 5, 13, and these piping 15, 16,
first, second and third valves 2 disposed in 17;
It is generally composed of 0, 21, 22, etc. In order to transfer the resist liquid 1 from the first container 2 to the second container 5, the piping 15 includes first, second, third and fourth pipes 15A, 15B, 15C,
15D, and the filter 7 is interposed in the middle of the second pipe 15B. The piping 16 for transferring the resist liquid 1 from the second container 5 to the first container 2 includes first, second, third and fourth pipes 1
Consisting of 6A, 15B, 15C, 16B,
The pipe 15 and the second and third pipes 15B and 16C
The first pipe 15A, 16A and the second pipe 15B
The first valve 20 is disposed at the connection between the second pipe 15B, the third pipe 15C and the pipe 17, and the second valve 21 is disposed at the connection between the second pipe 15B and the third pipe 15C and the pipe 17.
A third valve 22 is disposed at the connection portion with the pipes 15D and 16B, respectively. As the first, second, and third valves 20, 21, and 22, diaphragm-type three-way valves (for example, 856 manufactured by Meisteflon Flow Control Components) are used.

Next, a method for continuous filtration of approximately 1 kg of resist liquid 1 five times using the filtration apparatus configured as described above will be described in detail.

First, a first chamber containing the resist solution 1 to be filtered is prepared.
The container 2 is stored in the first pressurizer 3, and the second container 5 is empty.
is stored in the second pressurizer 10. Also, the first and second
And by switching the flow paths of the third valves 20, 21, 22, the first pipe 15A and the second pipe 15B, the second pipe 15B and the third pipe 15C, and the third pipe 15C and the fourth pipe 15D
The resist liquid 1 can be transferred through the piping 15 by communicating with the resist liquid 1. Next, _N2 gas is continuously supplied into the first pressurizer 3 from the first gas introduction pipe 4, and the pressure inside the pressurizer 3 is lowered by 0.4 from atmospheric pressure.
If the Kg/ ^cm2 is increased, the resist solution 1 in the first container 2
is transferred and accommodated in the second container 5 through the pipe 15, and when passing through the filter 7 on the way,
Foreign matter in the resist liquid 1 is removed by the filter 7. Note that when the resist solution 1 in the first container 2 is pressurized, a part of it is transferred to the fourth pipe 16B of the pipe 16.
is sent to and remains there. Then, when almost the entire amount of the resist liquid 1 is transferred to the second container 5 and the piping 15, the supply of N ₂ gas to the first pressurizer 3 is stopped,
The pressure inside the pressurizer 3 is returned to atmospheric pressure, and the flow paths of the first and third valves 20 and 22 are switched to transfer the resist liquid 1 from the second container 5 to the first container 2. That is, the first pipe 16A and the second pipe 15B of the piping 16 are communicated, and the third pipe 15C and the fourth pipe 16
Communicate with B. Thereby, the first and second containers 2 and 5 are connected to each other by the pipe 16. Next, _N2 gas is continuously supplied into the second pressurizer 10 from the second gas introduction pipe 12, and the second pressurizer 10
When the internal pressure is raised as described above, the resist liquid 1 in the second container 5 is transferred and stored in the first container 2 through the pipe 16, and the filter 7 removes foreign matter for the second time during the transfer. When almost the entire amount of the resist liquid 1 is transferred to the first container 2 and the piping 16, the supply of N ₂ gas to the second pressurizer 10 is stopped, and the pressure inside the pressurizer 10 is returned to atmospheric pressure. and the flow paths of the first and third valves 20 and 22,
Switching is again performed to transfer the resist liquid 1 from the first container 2 to the second container 5. That is, the first pipe 15A and the second pipe 15B are made to communicate with each other, and the third pipe 15C and the fourth pipe 15D are made to communicate with each other, and the first and second containers 2 and 5 are connected by the pipe 15.

Then, as described above, from the first container 2 to the second container
Transfer the resist solution 1 to the container 5, and then transfer it to the second container 5.
When the resist liquid 1 is transferred from the first container 2 to the first container 2, the resist liquid 1 has traveled back and forth between the first and second containers 2 and 5 twice. Therefore, foreign matter removal by the filter 7 is performed a total of four times by these two reciprocations.

Next, the flow paths of the first and second valves 20 and 21 are switched to transfer from the first container 2 to the third container 13. That is, the first and second pipes 15A and 15B of the pipe 15 are made to communicate with each other, and the second pipe 15B and the pipe 17 are made to communicate with each other. Then, the first gas introduction pipe 4
When N ₂ gas is continuously supplied to the first pressurizer 3 and the pressure inside the pressurizer 3 is increased in the same manner as described above, the resist liquid 1 in the first container 2 flows into the pipe 1.
5 first pipe 15A-first valve 20-second pipe 15B-
The foreign matter is transferred and housed in the third container 13 through the filter 7 - the second pipe 15B - the second valve 21 and the pipe 17, and when passing through the filter 7, foreign matter is removed for the fifth time. When almost the entire amount of resist liquid 1 is transferred and accommodated in the third container and piping 15A, the supply of _N2 gas to the first pressurizer 3 is stopped and the pressure inside the pressurizer 3 is returned to atmospheric pressure, and the resist Continuous filtration of liquid 1 is completed.

As described above, in this embodiment, the supply and stop of _N2 gas through the first and second gas introduction pipes 4 and 12,
By simply switching the flow paths of the first, second and third valves 20, 21 and 22, the resist liquid 1 can be continuously transferred back and forth between the first and second containers 2 and 5. 1 by hand into the second container 5
There is no need to transfer the liquid from the liquid to the first container 2, and the filtration operation is simple. In addition, the first and second containers 2 and 5 are connected to the first and second pressurizers 3 and 10, respectively.
Since the pipes 15 and 16, especially the first pipes 15A and 16A, are accommodated in the pipes 15 and 16, air does not enter the pipes 15 and 16, and in particular, the first pipes 15A and 16A. It is possible to reliably prevent contamination etc.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention. In this embodiment, the first and second pressurizers 3,
10, first and second three-way solenoid valves 30 and 31 (for example,
050LE1 manufactured by Koganei Seisakusho Co., Ltd., a weight measuring device 33 (for example, a weight measuring device manufactured by A&D Kiki Co., Ltd.) is disposed, and the first pressurizer 3 is placed thereon, Furthermore, the above point is provided with a control device 35 that drives and controls the first, second and third valves 20, 21, 22 and the first and second three-way solenoid valves 30, 31 based on the signal from the weight measuring device 33. This embodiment is different from the embodiment, but the other configurations are completely the same.

Next, a method for continuous filtration of about 1 kg of resist liquid 1 five times according to this embodiment will be described in detail.

First, a first chamber containing the resist solution 1 to be filtered is prepared.
The container 2 is housed in the first pressurizer 3, and the second container 5 is empty.
is stored in the second pressurizer 10. Next, the first and second
Then, the flow paths of the third valves 20, 21, and 22 are switched to connect the first and second containers 2 and 5 through the piping 15, and the first solenoid valve 30 is opened to supply N ₂ from the first gas introduction pipe 4. Gas is continuously supplied into the first pressurizer 3 to make the pressure inside the first pressurizer 3 higher than atmospheric pressure. Then, the resist liquid 1 in the first container 2 is transferred to the second container 5 through the piping 15, and on the way, it is filtered for the first time by the filter 7. At this time, the end value (lower limit) of the weight measuring device 33 is determined as the loss of the resist liquid 1 due to the filtration process, that is, when almost the entire amount of the resist liquid 1 in the first container 2 has been transferred to the pipe 15, the first container 2 Since the value obtained by adding the weight of the first pressurizer 3 to
The liquid is continuously transferred until the flow path is switched by the method described below. Furthermore, by setting the number of times of filtration of the resist liquid 1 in the control device 35, the resist liquid 1 is continuously filtered into the first container 3 as described later.
and the second container 5 while being filtered.

Now, when the weight measuring device 33 senses the value (lower limit value), the weight measuring device 33 sends it to the control device 35.
A signal is sent to (arrow A). This signal causes two three-way solenoid valve relays and two three-way valve relays (both not shown) in the control device 35 to operate, closing the first three-way solenoid valve 30 and closing the second three-way solenoid valve 31. Open the first and third
In order to switch the flow paths of the valves 20 and 22, signals are simultaneously sent to each valve (arrow B, arrow C, arrow D, arrow E). That is, the first three-way solenoid valve 30 is closed by the signal of the first three-way solenoid valve relay to stop the supply of _N2 gas through the first gas introduction pipe 4, and at the same time, as described later, the second container 5 is closed. In order to transfer and accommodate the resist solution 1 in the first container 2,
Leak pipe 3 coming out from the first three-way solenoid valve 30
Open 0A and return the inside of the first pressurizer 3 to atmospheric pressure. On the other hand, in order to change the flow paths of the first and third valves 20, 22 by signals from the two three-way valve relays, a valve (not shown) for guiding pressurized air to the valves 20, 22 is used. ) will be held. As a result, the flow paths of the first and third valves 20 and 22 are switched to send the resist liquid 1 from the second container 5 to the first container 2, and the first and second containers 2 and 5 are connected to the piping 16.
Connect with. Furthermore, since the second three-way solenoid valve 31 is opened by the signal from the second three-way solenoid valve relay, continuous supply of N ₂ gas by the second gas introduction pipe 12 is started, and the inside of the second pressurizer 10 is Raise the pressure above atmospheric pressure. Therefore, the resist solution 1 in the second container 5 is transferred and absorbed into the first container 2 through the pipe 16, and on the way, the resist solution 1 is filtered by the filter 7.
A second filtration is performed.

At this time, as the end value (upper limit) of the weight measuring device 33, when the loss of the resist liquid 1 due to the filtration process, that is, almost the entire amount of the resist liquid 1 in the second container 5 has been transferred to the pipe 16, the first container 2 By setting in advance a value that is the sum of the weight of the resist liquid not stored in the container (for example, 0.1 kg) and the weight of the first container 2 and the first pressurizer 3,
While the mabe resist solution 1 having this value is filtered by the filter 7, it is transferred from the second container 5 to the first container 2.
The liquid is continuously transferred until the flow path is switched by the method described below.

That is, when the weight measuring device 33 senses the above-mentioned value (upper limit value), the weight measuring device 33 sends a signal to the control device 35, and the control device 35 operates according to this signal, and the first and second 2 Three-way solenoid valve 3
0, 31 and the flow paths of the first and third valves 20, 22 are switched. As a result, the first three-way solenoid valve 30 opens, the second three-way solenoid valve 31 closes, and the second pressurizer 10 is returned to atmospheric pressure through the leak pipe 31A.
The first and second containers 2 and 5 are connected by a pipe 15 by switching the flow paths of the first and third valves 20 and 22. This completes one round trip of the resist liquid 1.

When the series of operations described above is repeated once again and the resist liquid 1 is made to reciprocate once more, the filter 7
Filtration is performed four times in total. And 4
When the first filtration is completed and almost the entire amount of the resist liquid 1 is contained in the first container 2 and the piping 16, a counter (not shown) in the control device 35 counts the number of times of filtration and the second valve 21 is closed. A second signal is sent to change the flow path.
Sends to a three-way valve relay (not shown). Then, the relay for the second three-way valve operates and sends out a signal (arrow F), and this signal causes the second valve 21
In order to change the flow path of the second valve 2, a valve (not shown) for guiding the pressurized air opens, and by switching the flow path of the second valve 2, the second pipe 15B and the pipe 17 are communicated. . In addition, the first and second three-way solenoid valves 30,
31 and the operations of the first and third valves 20 and 22 are as described above. For this reason, the resist liquid 1 in the first container 2 is transferred to the first and second pipes 15A and 15B of the pipe 15.
The liquid is then transferred to the third container 13 through the pipe 17, and is filtered for the fifth time by the filter 7 along the way.

At this time, the weight measuring device 33 senses the above-mentioned value (lower limit value) and sends a signal (arrow A) to the control device 35. Since the control device 35 has already counted the fourth filtration, this signal causes only the first three-way solenoid valve relay in the control device 35 to operate and close the first three-way solenoid valve 30. As a result, the supply of N ₂ gas through the first gas introduction pipe 4 is stopped, and the pressure inside the first pressurizer 3 is returned to atmospheric pressure through the leak pipe 30A of the electromagnetic valve 30, thereby filtering the resist liquid 1. end.

Therefore, according to the filtration device having such a configuration, repeated filtration can be performed continuously and automatically, similarly to the above embodiment.

In addition, in each of the above embodiments, the weight measuring device 33
Although a case has been described in which the container is disposed below the first container 2, the present invention is not limited to this, and it goes without saying that the container may be disposed below the second container 5.

Further, in the first and second embodiments described above, the gas pressure of an inert gas is used as a means for transferring the resist liquid, but the present invention is not limited to this. A pump may be provided, and if the second pipe 15B of the pipes 15 and 16 is further provided with a pump, only one pump is required. Furthermore, it is better to install the pump in the flow path in front of the filter 7, considering the dust generated from the pump. That is, when disposed in the second pipe 15B, the second pipe 15 between the first valve 20 and the filter 7
It is better to set it in B.

〔Effect of the invention〕

Since the filtration device according to the present invention has the configuration described above, repeated filtration can be performed continuously by simply switching the channels of the first, second and third valves and the means for transferring the liquid. can be carried out according to
Easy to work with. In addition, since there is no need to manually transfer the liquid each time despite repeated filtration, there is no risk of contamination of the piping or air entering the piping, and therefore, it is possible to remove liquids such as resist liquid. Repeated filtration can be performed effectively,
The cleanliness of the filtered liquid can be increased,
It also improves the durability of filtering means such as filters.

Further, in the present invention, the control device is operated by a signal from the weight measuring device, and the control device operates the first,
The control of the second and third valves and the means for transferring the liquid allows complete automation of continuous filtration.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a first embodiment of the present invention, FIG. 2 is a schematic block diagram showing a second embodiment of the present invention, and FIG. 3 is a schematic block diagram showing a conventional example of a filtration device. . DESCRIPTION OF SYMBOLS 1... Resist liquid, 2... First container, 3... First pressurizer, 4... First gas introduction pipe, 5... Second container, 7... Filter, 10... Second pressurizer, 12... Second gas introduction pipe , 13...Third container, 15, 16, 17... Piping,
20...first valve, 21...second valve, 22...third valve, 3
0...First three-way solenoid valve, 31...Second three-way solenoid valve, 3
3... Weight measuring device, 35... Control device.

Claims (1)

Claims: 1. First and second containers containing a liquid to be filtered, means for transferring the liquid from the first container to the second container and vice versa, and means for filtering the liquid. and a third container that ultimately accommodates the liquid filtered by the filtration means, the liquid being transferred from these containers into a flow path connecting the first container and the second container. a first valve that is controlled to send the liquid to the filtration means; a second valve that is controlled to selectively send the liquid discharged from the filtration means to the third container and the third valve; 3
A filtration device characterized in that the liquid transferred to the valve is controlled to be selectively sent to the first and second containers by the valve. 2. first and second containers containing the liquid to be filtered, means for transferring the liquid from the first container to the second container and vice versa, means for filtering the liquid, and the filtering means and a third container that finally accommodates the filtered liquid, and the liquid transferred from these containers is transferred into the flow path connecting the first container and the second container to the filtering means. a first valve controlled to selectively send the liquid discharged from the filtration means to the third container and the third valve, and a second valve controlled to selectively send the liquid discharged from the filtration means to the third valve; The liquid is controlled to be selectively sent to the first and second containers by the valve, and further a weight measuring device is provided below the first container or the second container, and a weight measuring device is provided below the first container or the second container, and A filtration device comprising a control device that controls the liquid transfer operation and switches the flow paths of the first, second, and third valves in response to an instruction.