JPH0614831Y2 - Dripping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an apparatus for dropping liquids such as a semiconductor manufacturing resist solution, a resist thinner, a resist developing solution, an etching solution and a rinse solution, and particularly The present invention relates to a dropping device capable of advancing the transfer for clean filtration and the dropping of a filtered liquid at the same time.

[Prior Art] FIG. 3 shows an example of a conventional dropping device disclosed in Japanese Utility Model Publication No. 61-188353. That is, a container 2 for containing a liquid 1 such as a resist liquid, and a self-contained pump 3 for sucking the liquid 1 in the container 2 and circulating the liquid 1 through a filter (filtering means) 4 back into the container 2 , The filter 4 for microfiltration of the liquid 1, a nozzle 7 for dropping the filtered liquid 1, a two-way valve 5 for dropping the liquid 1 through the nozzle 7, and a desired amount of liquid from the nozzle 7. In order to prevent unnecessary liquid 1 from dropping from nozzle 7 after dropping 1, liquid overdrip prevention valve (hereinafter referred to as “drawback valve”) 6 that sucks back liquid 1 is provided. These constitute the dropping device 20.

Next, a method of dropping the filtered resist solution using this dropping device will be described.

First, in order to perform the filtering operation, the two-way valve 5 is closed, the self-contained pump 3 is continuously operated, the resist solution 1 contained in the container 2 is sucked by the self-contained pump 3, and the filter 4 Send to. Then, the resist solution 1 filtered by the filter 4 is returned to the container 2. By repeating this circulation, the resist solution 1 is filtered with high accuracy.

Next, in order to perform the dropping work, the self-contained pump 3 is operated,
The two-way valve 5 is opened and the resist solution 1 is dripped from the nozzle 7. Immediately after the dropping, the two-way valve 5 is closed and the drawback valve 6 is operated to suck back the unnecessary resist liquid 1 from the nozzle 7 to drop a desired amount of the resist liquid 1.

In this way, all the resist solution 1 is constantly circulated in the system 8 for filtration except when the resist solution 1 is dropped, while when the resist solution 1 is dropped, the circulating resist solution 1 is used.
A part of the liquid is dropped from the nozzle 7 through the two-way valve 5.

[Problems to be Solved by the Invention] By the way, in the conventional device, since the circulation path for increasing the cleanliness of the liquid 1 in the container 2 is a single path, the liquid 1
As a means for circulating the gas through the filter 4, an inert gas for pressurization excellent in continuous transfer cannot be used. That is, even if the inside of the container 2 is pressurized with an inert gas for pressurization,
This is because the inlet and outlet of the system passage 8 submerged in the liquid 1 have the same pressure. Therefore, there is a problem that the circulation means is limited to the above-mentioned self-contained pump (for example, a diaphragm pump).

In addition, when the circulation means is a self-contained pump, the liquid is intermittently transferred due to its structure, so that the change in the viscosity of the liquid and the solid matter are filtered by the generation of the wave in the filter and the forced passage of the liquid. There was a problem of passing through the filter 4 and detaching from the filter 4.

An object of the present invention is to eliminate the above-mentioned problems of the prior art by using a two-system path for cleaning the liquid in the container and performing reciprocating transfer of the liquid without using a self-contained pump. Another object of the present invention is to provide a dropping device capable of dropping a cleaner liquid.

[Means for Solving the Problems] A drip apparatus of the present invention is a first and second container for containing a liquid to be filtered, and a forward path for reciprocating the liquid between the first container and the second container. And a return path, a means for pumping the liquid by gas pressure in order to transfer the liquid back and forth, a reciprocal path provided between the forward path and the return path, and having a common forward path and the return path, Means for filtering the liquid that is reciprocally transferred, and means for dripping the liquid filtered by the filtering means, which is provided upstream of the reciprocating path and in the forward path and the returning path downstream of the first valve, which will be described later. It is equipped with.

Further, a first valve that is provided in the forward path and the return path on the upstream side of the filtering means and that controls to selectively send the liquid transferred from the first container or the second container to the filtering means; A second valve provided in the forward path and the return path on the downstream side, which controls to selectively send the liquid filtered by the filtering means to the first container and the second container, and is housed in the first container and the second container. Means for detecting the liquid amount of each of the liquids to be detected and a detection signal from the liquid amount detecting device to switch the reciprocating transfer of the liquid, which is reduced by the dropping of the dropping device, the pressure feeding means, the first valve and the first valve. A control device for controlling the two valves is provided.

In a preferred embodiment of the present invention, at least the liquid contact part of each part constituting the apparatus is a chemical-resistant resin or borosilicate that prevents foreign matter from entering the liquid contact part during liquid transfer. It is made of glass.

[Operation] When gas pressure is continuously applied to the first container containing the liquid,
The liquid in the first container is pressure-fed to the outward path without pressure fluctuation or wave. Then, the liquid is guided to the filtering means through the first valve, stably filtered there, and then transferred to the second container through the second valve. This transfer is under the control of the controller until the flow rate detecting means of the first container detects only a small amount of liquid or the liquid amount detecting means of the second container detects the amount of liquid necessary for reciprocating transfer. I can continue.

When the transfer in the forward path is completed, the supply of the gas pressure is switched from the first container to the second container under the control of the controller, and the liquid in the second container is pumped to the return path. Then,
The liquid is guided to the filtering means through the first valve, where it is filtered and then transferred back to the first container through the second valve. This return transfer is under the control of the controller until the liquid amount detection means of the second container detects only a small amount of liquid or the liquid amount detection means of the first container detects the amount of liquid necessary for the reciprocating transfer. I can continue.

In this way, the liquid is microfiltered while being repeatedly transported back and forth between the first container and the second container.

By the way, even during this reciprocating transfer, the filtered liquid is appropriately dropped from the dropping means. Therefore, the liquid that is reciprocally transferred due to the dropping gradually decreases. Even if the amount of liquid becomes small, if the transfer is still continued, air will enter into the reciprocating path. However, before that, the liquid amount detecting means detects this before stopping the reciprocating transfer so that such a problem does not occur.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing an embodiment of a dropping device according to the present invention.

In the dropping apparatus of this embodiment, first, the resist liquid 1 to be filtered is
The first container 2 and the second container 11 for storing the
The forward and backward paths 16 and 17 and the backward paths 15 and 18 through which the resist solution 1 reciprocates between the first and second containers 11 and the forward and backward paths, which are provided between the forward paths 16 and 17 and the backward paths 15 and 18. A passage 50 and a pipe 41 for blowing an inert gas for pressurization (for example, N ₂ gas) as a pressure-feeding means into the first container 2 and the second container 11 to reciprocate the resist solution 1 by pressure-feeding, respectively. 42, a filter 4 that is provided in the reciprocating path 50 and filters the resist solution 1 that is reciprocally transferred, and the resist solution 1 that is filtered by the filter 4.
7, a draw back valve 6 (for example, Meisteflon Flow Control Components Co., Ltd. 990-01) for preventing the resist liquid 1 from dropping more than a desired amount from the nozzle 7, and a filter 4.
A two-way valve 5 (for example, 856 manufactured by Meisteflon Flow Components Co., Ltd.) provided between the drawback valve 6 and the drawback valve 6 to control the resist liquid 1 discharged from the filter 4 to be sent to the nozzle 7. .

The above two containers are configured as a pressure container. Further, the relationship between the forward path and the return path is a name given by using the first container 2 as the starting container, and when the second container 11 is used as the starting container, the relationship between the outgoing path and the returning path is reversed, In particular, the name does not have a fixed meaning.

Further, a first valve for controlling the resist liquid 1 transferred from the first container 2 and the second container 11 to be selectively sent to the filter 4 is provided in the forward path 16 and the return path 18 on the upstream side of the filter 4. . In the illustrated example, the first valve is a check valve 23 provided on the outward path 16 and a check valve 2 provided on the return path 18.
4 and. One check valve 23 is used for the first container 2
From the second container 11 to the second container 11 but prevents its reverse transfer and the other check valve 24 allows the return transfer from the second container 11 to the first container 2, but It is designed to prevent reverse transfer.

Further, the second valve for controlling the resist liquid 1 filtered by the filter 4 to be selectively sent to the first container 2 and the second container 11 is a forward path 17 and a return path 15 on the downstream side of the filter 4.
It is provided inside. In the illustrated example, this second valve is composed of a two-way valve 21 provided in the return path 15 and a two-way valve 22 provided in the outward path 17. These two-way valves 21, 22 have the same structure as the two-way valve 5 described above.

Further, the first container 2 and the second container 11 are provided with means for detecting the presence or absence of the liquid amount of the resist liquid 1 contained in these containers. In the illustrated example, the liquid amount detecting means is configured so that the liquid level of the resist liquid 1 in each of the containers 2 and 11 is 3 above and below.
An upper limit sensor 31, which detects the height of each step separately,
51, intermediate sensors 32 and 52, lower limit sensors 33 and 53
(For example, capacitance type proximity switch E2K manufactured by Tateishi Electric Co., Ltd.
-C).

Then, in response to the detection signal from the liquid amount detecting means, the pressure feeding means and the first valve, so as to automatically repeat the reciprocating transfer of the resist solution 1 which gradually decreases due to the dropping from the nozzle 7, A control device 60 for controlling the second valve is provided.

Here, as the control of the pressure feeding means by the control device 60, for example, three-way valves (not shown) are respectively provided in the pipes 41 and 42, and these are controlled to control the first container 2 or the second container 1.
The inert gas supplied to any one of the containers 1 is switched to the other container, and the atmospheric opening is switched from the other container to the one container.

By the way, as described above, the first container 2 or the second container 11
The reason why the liquid level detection sensors are attached to both of them instead of one of them is as follows. That is, in this example, since the reciprocating transfer and the dropping can be performed at the same time or can be performed at the same time, the amount of the resist solution 1 in the first container 2 and the second container 11 is the amount of the dropping of the resist solution 1. This is because both containers need sensors for switching the pressure of the containers. For example, even in the case of only one container with a sensor, the container can be switched by the upper limit sensor and the lower limit sensor if the liquid amount does not change. However, as in this example, when the liquid amount decreases, the liquid amount does not always reach the position of the upper limit sensor, so it is necessary to attach the upper and lower limit sensors to the other container to control the reciprocating transfer. is there. Also, in order to prevent the resist solution 1 from solidifying due to the inclusion of air in the forward path and / or the return path, the reciprocating transfer is stopped when the lower limit sensors of both containers cannot detect the height at which the resist solution 1 exists at the same time. It is also because of the reason.

Also, the function of the sensors in the container and their position,
The relative positional relationship is determined as follows.

First, the upper limit sensors 31 and 51 are connected to the first container 2 and the second container 2.
In order to prevent the resist solution 1 from spilling from the container 11,
It is a sensor for switching the pressure of the container. The amount of these sensors you want to transfer back and forth (the amount used for dropping +
The resist solution 1 of (α) and the container volume from the state where the resist solution 1 is not contained in the container to the position of the lower limit sensors 33 and 53 are added together is contained in only one container. At the position of the liquid level in the container at that time, attach it while detecting the liquid level.

Next, the lower limit sensors 33 and 53 are sensors for switching the containers in order to prevent air from entering the reciprocating paths, and the reciprocating paths 15, 16 inserted into the respective containers,
It is located slightly above the lower ends of 17, 18.

The intermediate sensors 32 and 52 are sensors used to select a container to start reciprocating transfer. These sensors are above the lower limit sensors 33 and 53, and the upper limit sensors 31,
It is positioned below the liquid level in the container having a volume half that of the container from the position 51 to the positions of the lower limit sensors 33 and 53.

In addition, at the start of the reciprocal transfer, the first container 2 and the second container 11
When the intermediate sensors 32 and 52 do not detect the liquid at the same time, the resist liquid 1 needs to be replenished in the first container 2 or the second container 11 because the amount is less than the amount used for dropping.

Next, the procedure for dropping the resist solution 1 according to this example will be described.

First, the selection of the container to which the gas pressure is applied at the start of filtration is performed by the control device 60 which receives the detection signals of the intermediate sensors 32 and 52. For example, the intermediate sensor 32 of the first container 2
However, when the resist liquid 1 is detected, the second container 11
Regardless of whether the intermediate sensor 52 of the
The two-way valve 21 in the return path 15 and the two-way valve 5 leading to the nozzle 7 are closed, and the first container 2 is pressurized with the inert gas injected from the pipe 41 to remove the resist solution 1 in the first container 2. Send to the check valve 23. At this time, the second container 11 is open to the atmosphere through the pipe 42 under the control of the control device 60. In addition, the two-way valve 22 in the outward path 17 leading to the second container 11
Are opened in synchronization with the pressurization of the first container 2. The resist solution 1 sent to the check valve 23 passes through the filter 4,
Transferred from the two-way valve 22 to the second container 11. This transfer is continued until the lower limit sensor 33 of the first container 2 stops detecting liquid or the upper limit sensor 51 of the second container 11 detects liquid. When the control device 60 receives the detection signal from the lower limit sensor 33 or the upper limit sensor 51, the first container 2 is switched to the second container 11, that is, the supply of the inert gas for pressurization is instantaneously switched. . The reason why the switching is performed instantaneously is that a suitable amount of the resist solution 1 is dropped even if the switching occurs when the resist solution 1 is dropped.

On the other hand, when the intermediate sensor 52 in the second container 11 is detecting the liquid and the intermediate sensor 32 of the first container 2 is not detecting the liquid, the controller 60 controls the control device 60 to provide the forward path 17. The two-way valve 22 and the two-way valve 5 are closed, the second container 11 is pressurized by the inert gas injected from the pipe 42, and the resist solution 1 in the second container 11 is supplied to the check valve 24 of the return path 18. Send to. At this time, the first container 2 is open to the atmosphere via the pipe 41. Return path 1
The two-way valve 21 provided to the first container 2 to 5 is opened in synchronization with the pressurization of the second container 11. The resist solution 1 sent to the check valve 24 is transferred from the two-way valve 21 to the second container 2 through the filter 4. This return transfer is the second
The process is continued until the lower limit sensor 53 of the container 11 stops detecting liquid or the upper limit sensor 31 of the first container 2 detects liquid. Lower limit sensor 53 or upper limit sensor 3
When the control device 60 receives the detection signal from 1, the switching of the supply of the pressurized inert gas from the second container 11 to the first container 2 is instantaneously performed.

Thus, under the control of the control device 60, the first
The reciprocating transfer between the container 2 and the second container 11 is automatically repeated alternately.

In the reciprocating transfer state, when the upper limit sensors 31 and 52 simultaneously detect liquid and when the lower limit sensors 33 and 53 do not simultaneously detect liquid, pressurization is stopped and an alarm is issued.

Next, a procedure for dropping the resist solution 1 will be described. As described above, the reciprocating transfer of the resist solution 1 is repeated between the first container 2 and the second container 11, and the two-way valve 5 leading to the nozzle 7 is opened in this state. Then, whichever of the first container 2 or the second container 11 is in the pressurized state,
The resist solution 1 discharged from the filter 4 is always dropped from the nozzle 7 through the two-way valve 5. In this way, the reciprocating transfer is constantly repeated, so that the resist liquid 1 to be microfiltered is dripped from the nozzle 7.
The dropped resist liquid 1 becomes extremely clean. And
After this dropping, the two-way valve 5 is closed and the drawback valve 6 is operated to prevent the resist solution 1 from dripping from the nozzle 7.

As described above, according to the present embodiment, since the resist solution is reciprocally transferred in the two-path structure, it is possible to adopt the pressurizing and pressure-feeding method using the inert gas, thereby minimizing the pressure change and the wave. be able to. Therefore, it is possible to effectively prevent the sudden pressure change that occurs when using a self-contained pump that must be adopted in the case of a one-passage, the change in viscosity from the filter due to wave motion, and the generation of solid matter. . As a result, the foreign matter in the resist solution can be reliably filtered, and the cleanliness of the resist solution can be always kept high.

In addition, in this embodiment, in particular, since the reciprocal transfer and the dripping simultaneously proceed, and the two-system path configuration in which the resist liquid is reduced by the dripping during the reciprocating transfer is adopted, the first container and the second container are Since a sensor that detects the liquid level is installed on both sides and the amount of liquid in the container is constantly monitored, not only the resist liquid spills from the container, but also an insufficient amount of liquid causes air to flow in the reciprocating path. It can be prevented from being mixed in advance, and therefore, the switching of the reciprocating transfer can be appropriately performed.

In the above embodiment, the check valve is provided on the upstream side of the reciprocating path, but a two-way valve may be provided instead of the check valve. In this case, the control device 60 opens the two-way valve provided at the position of the one check valve 23 at the same time as the pressurization of the first container 2 and the position of the other check valve 24 at the same time as the pressurization of the second container 11. You can open the two-way valve provided in.

Further, the filter 4 as the filtering means is provided in the reciprocating path 50, but as shown by the broken line in FIG. 1, the outward path 16 and the returning path upstream of the reciprocating path 50 and downstream of the first valves 23 and 24. 18 may be provided respectively.

Further, as shown in FIG. 2, a three-way valve 70 may be provided instead of the check valves 23 and 24. In this case as well, the opening / closing direction of the three-way valve 70 needs to be controlled by the control device 60 by the container to be pressurized.

Further, although the liquid level sensor is used as the liquid amount detecting sensor, a liquid weight measuring sensor may be used.

[Effect of the Invention] According to the present invention, two containers are provided, the system path for cleaning the liquid in the container is two paths, and the liquid is reciprocally transferred by gas pressure pumping without using a self-contained pump. Since the foreign matter in the liquid is effectively captured by the filtering means without pressure fluctuations and vibrations, a cleaner liquid can be dripped, which means that the yield is increased particularly in the semiconductor manufacturing process. Can be raised. In addition, in particular, since the means for detecting the liquid amount of the liquid is provided in both the containers, even if the liquid amount is decreased by the dropping, the pressure feeding for the reciprocating transfer and the switching of the valve can be smoothly and automatically performed. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention, and FIG. 3 is a schematic configuration diagram showing an example of a conventional device. In the figure, 1 is a resist liquid which is an example of a liquid, 2 is a first container, 4 is a filter as a filtering means, 7 is a nozzle as a dropping means, 11 is a second container, 16 and 17 are outward paths, 1
5, 18 are return paths, 21 and 22 are two-way valves as the second valve,
Reference numerals 23, 24 and 70 denote check valves and three-way valves as first valves, 31, 32, 33, 51, 52, 53 liquid level sensors as liquid amount detecting means, 50 a reciprocating path, 41, 4
2 is a pipe for injecting an inert gas as a pressure feeding means, and 60 is a control device.

Claims (1)

[Scope of utility model registration request] 1. A first and a second container for containing a liquid to be filtered, a forward path and a return path for reciprocating the liquid between the first container and the second container, and a reciprocating transfer of the liquid. For this purpose, a means for pumping the liquid by gas pressure, a reciprocating path provided between the forward path and the return path and having a common forward path and a backward path, in the reciprocating path or on the upstream side of the reciprocating path. Further, means for filtering the liquid that is reciprocally transferred, means for dropping the liquid filtered by the filtering means, and means for dropping the liquid filtered by the filtering means, and upstream of the filtering means, which are provided in the forward path and the return path downstream of the first valve described later. A first valve which is provided in the forward path and the backward path and controls the liquid transferred from the first container or the second container to be selectively sent to the filtering means; and in a forward path downstream of the filtering means, and It is filtered by the filtering means provided in the return path. A second valve that controls to selectively send the liquid to the first container and the second container, a unit that detects the liquid amount of the liquid contained in the first container and the second container, and the liquid. And a control device for controlling the pressure feeding means and the first valve and the second valve to switch the reciprocating transfer of the liquid, which is reduced by the dropping of the dropping means, in response to the detection signal from the amount detecting means. Characteristic dripping device.