JPS62171124A - Dropping method for liquid - Google Patents

Abstract

PURPOSE:To prevent the nonuniform or discontinuous dropping of a liquid, the dropping of unnecessary liquid onto a substance to which the liquid is dropped, at the time when the dropping is ended, and the mixing of dust in the dropping liquid, by a method wherein after pressure is applied to the inside of a vessel, an on-off valve is opened so that a liquid stored in the vessel be dropped from a dropping nozzle, and the on-off valve is closed after the dropping of the liquid ended with release of the pressure. CONSTITUTION:An opening drive signal A1 is impressed on a three-way solenoid valve 18 by a control unit 21 to open this valve. Inactive gas is supplied into a pressurizing vessel 16 to make the pressure therein higher than the atmospheric pressure, thus applying a pressure to the inside of a vessel 11. After a compression time (b) passes, an opening drive signal B1 for an on-off valve 13 is impressed from the control unit 21 to open this valve, and thus the dropping of a liquid 10 having been compressed in a transfer passage 12 is started. After a dropping time (c) passes, the control unit 21 closes the three-way solenoid valve 18. Then, the inactive gas in the pressurizing vessel 16 is discharged through a gas discharge pipe 20. Consequently, the pressure applied to the inside of the vessel 11 is released, and the dropping of the liquid 10 is also ended.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for dropping liquids such as resist liquids for semiconductor manufacturing, resist thinners, resist developers, etching liquids, and rinsing liquids. The present invention relates to a method for dropping a liquid that can prevent the liquid from being dropped unevenly or discontinuously at the start of dropping, and can also prevent unnecessary liquid from falling onto an object after dropping the liquid.

[Conventional technology]

Conventionally, the following method is known as a method for dropping a liquid. That is, as shown in FIG. 3, liquid 1 such as a resist solution is sucked from inside a container 2 storing liquid 1 through a transfer passage 3 by a self-contained pump 4, and then transferred to a transfer passage 5. The liquid 1 is transferred through the drawback valve 6 and the transfer passage 7, and a desired amount of the liquid 1 is dripped from the dripping nozzle 8 onto the object 9 to be dripped. The draw pack valve 6 is a liquid fall prevention valve for preventing unnecessary liquid 1 from falling from the drip nozzle 8. If this draw pack valve 6 is not used, the drip nozzle 8 will be damaged as shown in FIG. 4(a). The liquid 1' remains in the opening 8a at the tip of the dropper, and this remaining liquid 1' falls onto the object 9 after dropping. Therefore, by operating the drawback valve 6 immediately after the dropping of the liquid 1 is completed, the remaining liquid 1' is sucked back through the transfer passage 7 as shown in FIG. This prevents it from falling onto objects 9.

[Problem that the invention seeks to solve]

However, in the conventional liquid dripping method, it is difficult to suction or transfer the liquid 1 smoothly due to insufficient pressure immediately after the self-contained pump 4 starts operating, and the transfer passage 5,
7. Due to the difficulty in transmitting the transfer pressure of the self-contained pump 4 to the liquid 1 in the draw pack valve 6° and the dripping nozzle 8, the liquid 1 may be distributed unevenly or unevenly on the object 9 when dropping the liquid 1. Easy to drip continuously.

In addition, when dropping different types of liquid, the transfer passage 3
．． 5,7. Self-contained pump 4. The liquid transfer section consisting of the drawback valve 6 and the dripping nozzle 8 must be cleaned using thinner, pure water, or the type of liquid to be dripped next. Since the structure of the liquid transfer section (not shown) is complicated, a sufficient cleaning effect cannot be obtained unless multiple mouths of liquid are used for cleaning. Therefore, especially when the liquid used for cleaning is expensive (for example, resist liquid), the production cost required for dropping the liquid increases. Furthermore, due to the operation of the self-contained pump 4 and the drawback valve 6, which have a complicated liquid transfer structure, minute dust is generated from these liquid transfer sections (so-called dust generation), and the dust is mixed into the dripping liquid 1. pure liquid 1 is mixed onto the dripping object 9.
cannot be dripped.

The present invention has been made in view of the above-mentioned circumstances, and there is a problem in that the liquid is dropped unevenly or discontinuously at the start of dropping the liquid, and that unnecessary liquid is dropped onto the object to be dropped when the dropping of the liquid ends. It is an object of the present invention to provide a method for dropping a liquid, which prevents the liquid from falling into the liquid, and further allows a pure liquid to be dropped by making it difficult for dust to be mixed into the liquid to be dropped.

[Means for solving problems]

The present invention has been made to achieve the above-mentioned object, and includes a method in which a liquid stored in a container is dripped from a dripping nozzle through a transfer passage, in which pressure is applied in the container by a pressurizing means. After adding the liquid, the liquid is discharged from the dripping nozzle by opening an on-off valve provided between the container and the dripping nozzle located above the liquid level in the container. Dripping of a liquid is started, and while the on-off valve is being driven to open, the pressure of the pressurizing means is released to end the dropping of the liquid, and then the on-off valve is driven to close. It's a method.

[For production]

After applying pressure in the container with the pressurizing means, when the on-off valve is opened, the transfer pressure from the pressurizing means is reliably transmitted to the liquid in the transfer passage and the dripping nozzle, and the liquid starts dripping from the dripping nozzle. do.

Additionally, when the on-off valve is driven to open, if the pressurization of the pressurizing means is released to finish dripping the liquid, and then this on-off valve is driven to close, a portion of the liquid in the dripping nozzle will flow toward the on-off valve side. and is sucked back.

[Example] Hereinafter, a liquid dropping method according to an example of the present invention will be described in detail. FIG. 1 is a schematic configuration diagram showing a liquid dropping device according to this embodiment, and FIG. 2 is a timing chart showing the operation of a three-way solenoid valve and an on-off valve that constitute a pressurizing means.

The liquid dropping device according to this embodiment is a positive type photoresist! - a container 11 for storing a liquid 10 (e.g. IP-1350 manufactured by Nijiplay), and a container 11 for storing a liquid 10 from the container 11
and an air-driven diaphragm pressurized two-way valve (e.g. 85 manufactured by Maize Teflon Flow Control Components).
6), a transfer passage 14 connecting the on-off valve 13 and a drip nozzle 15 (described later), and a drip nozzle 1
5, and further a container 1 constituting the pressurizing means.
1, a first gas introduction pipe 17 for supplying an inert gas (e.g. N2 gas) into the pressurized container 16, and a three-way pipe for switching the flow path of the inert gas. Equipped with a solenoid valve 18 (e.g. 0501E1 manufactured by Koganei Seisakusho), a second gas inlet pipe 19 that sends inert gas to the first gas inlet pipe 17 via the three-way solenoid valve 18, and a gas exhaust pipe 20. Furthermore, it has a control device 21 that controls the operation of the on-off valve 13 and the three-way solenoid valve 18. Note that the opening 15a at the tip of the dripping nozzle 15 allows the liquid 1 in the container 11 to
It is arranged at a position 1 m higher than the liquid level 10a of 0.

Next, a method of dropping the liquid 10 onto the object 22 using this dropping device will be described.

First, in preparation for dropping, in order to cause the liquid 10 to reach the opening 15a at the tip of the dropping nozzle 15, the control device 21 applies the opening drive signal A1 to the three-way solenoid valve 18 for a predetermined time a (for example, 2 seconds). The three-way solenoid valve 18 is driven to open by this opening drive signal A1, the second gas introduction pipe 19 and the first gas introduction pipe 17 are connected, and the inert gas is introduced into the second gas introduction pipe 19.
The inert gas is sent to the first gas introduction pipe 17 and supplied into the pressurized container 16, so that the pressure inside the pressurized container 16 is raised to 0.4'kg/Cm2 higher than atmospheric pressure. On the other hand, at the predetermined time a, the opening drive signal B1 is simultaneously applied to the on-off valve 13 to drive the on-off valve 13 open, thereby communicating the transfer passages 12 and 14. Then, the liquid 10 in the container 11 is transferred to the transfer passage 1
2. Open/close valve 13. The liquid then passes through the transfer passage 14 and reaches the opening 15a at the tip of the dripping nozzle 15. Next, after the predetermined time a has elapsed, the control device 21 applies a closing drive signal A to the three-way solenoid valve 18.

is applied to close the three-way solenoid valve 18 to stop sending the inert gas from the second gas introduction pipe 19 to the first gas introduction pipe 17, and to close the three-way solenoid valve 18 to stop sending the inert gas from the second gas introduction pipe 19 to the first gas introduction pipe 17. 20 to supply the inert gas in the pressurized container 16 to the first
The gas is discharged from the gas introduction pipe 17 to the gas discharge pipe 20 to return the pressure inside the pressurized container 16 to atmospheric pressure, and at the same time, the on-off valve 1 is
3, the on-off valve 13 is driven to close by applying the closing drive signal Bo. At this time, the three-way solenoid valve 18 is driven to close and the pressurized container 16 is closed.
Returning the internal pressure to atmospheric pressure and closing the on-off valve 13 are performed at the same time, so the liquid 10 is transferred to the transfer passage 12.14.
and remains within the drip nozzle 15.

Next, a method for dropping the liquid 1 onto the object 22 will be described.

First, in the control device 21, as shown in FIG.
Compression time b (e.g. 0.5 seconds) to prevent liquid 10 from being dropped unevenly or discontinuously, dropping time C
(e.g. 3.0 seconds) and drawback time d to prevent unnecessary liquid 10 from falling (e.g. 1.2 seconds)
Set. Next, the control device 21 is actuated to apply the opening drive signal A1 to the three-way solenoid valve 18 to drive the three-way solenoid valve 18 open, supplying inert gas into the pressurized container 16, and The pressure inside the container 11 is increased to 0.4 kg/cm2 higher than atmospheric pressure. However, until the compression time elapses after the start of the opening drive of the three-way solenoid valve 18, the open drive signal B1 of the on-off valve 13 is not applied and the on-off valve 13 is driven to close, so the liquid 10 is transferred to the transfer passage 1. The liquid is compressed within the container and is not transferred, so it is not dripped from the dripping nozzle 15. After the compression time has elapsed after starting the opening drive of the three-way solenoid valve 18,
An opening drive signal B1 for the on-off valve 13 is applied from the control device 21 to drive the on-off valve 13 to open. Then, the liquid 10 starts to be transferred from the container 11 to the dripping nozzle 15.
5, the liquid 10 is also started to be dropped onto the dripped object 22F, and the liquid 10 continues to be dropped until the dropping time C has elapsed. When the dripping time C has elapsed, the control device 21 closes the three-way solenoid valve 18.
A closing drive signal Ao is applied to drive the three-way solenoid valve 18 to close. Then, the supply of inert gas into the pressurized container 16 is stopped, and at the same time, the inert gas in the pressurized container 16 is discharged from the gas discharge pipe 20, so that the pressure in the container 11 is released and the liquid 10 The dripping is also completed. Note that even after this pressurization is released, the on-off valve 13 remains open until the drawback time d has elapsed, and at this time, the liquid 10 existing from the dripping nozzle 15 to the transfer passage 12 is compressed due to its own weight. It tends to return into the container 11 and therefore some of the liquid 10 in the drip nozzle 15 is also sucked back. Then, when the drawback time d has elapsed, the control device 21 applies a closing drive signal Bo to the on-off valve 13 to close the on-off valve 13, and stops sucking back the liquid 10 in the dripping nozzle 15.

As described above, according to this embodiment, pressure is applied inside the container 11 by driving the three-way solenoid valve 18 open, and the on-off valve 13 is driven closed until the compression time has elapsed. Since the opening/closing valve 13 is opened and the liquid 10 starts dropping after
can be prevented from being dripped unevenly or discontinuously. Further, the pressurization inside the container 11 is released by driving the three-way solenoid valve 18 to close, and the on-off valve 13 is opened until the drawback time d has elapsed, and after the drawback time d has elapsed, the on-off valve 13 is closed. Since it is driven, drip nozzle 1
A part of the liquid 10 in the liquid 5 is sucked back and the liquid 1 is returned to the opening 15a.
0 remains and unnecessary liquid 1 remains on the dripped object 22 after the dripping is completed.
0 can be prevented from falling. Furthermore, the transfer passage 12
14 and the on/off valve 13, and a self-contained pump or drawback valve with a complicated liquid transfer structure is not used, so that the dripping liquid 10 is less likely to contain dust and is pure liquid. 10 drops.

The present invention is not limited to the embodiments described above.

In this embodiment, the opening 15a at the tip of the dripping nozzle 15 is placed at a position 1 m higher than the liquid level 10a of the liquid 10 in the container 11, but it may be placed at any position higher than the liquid level 10a if necessary. good. In addition, a pressurized container 16° inert gas consisting of N2 gas, first and second gas introduction pipes 17.19.
Three-way solenoid valve 18. Although the pressurizing means is constituted by the gas exhaust pipe 20 and the gas exhaust pipe 20, a pressurizing means having other configurations may be adopted as necessary. Further, the compression time, drop time C, and drawback time d are not limited to the times shown in the examples, but may be determined as appropriate.

〔Effect of the invention〕

According to the liquid dropping method of the present invention, the liquid is dropped unevenly or discontinuously at the start of dropping the liquid, and
This prevents unnecessary liquid from falling onto the object upon completion of dropping the liquid, and furthermore, it is possible to drop pure liquid by preventing dust from getting mixed into the dropping liquid.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a liquid dropping device according to an embodiment of the present invention, and FIG. 2 shows a three-way solenoid valve constituting a pressurizing means,
A timing chart showing the operation with the on-off valve, Fig. 3 is a schematic configuration diagram showing a conventional liquid dripping device, and Fig. 4(a) shows the state of the liquid at the opening of the dripping nozzle when a drawback valve is not used. FIG. 2B is a diagram showing the state of the liquid at the opening of the dripping nozzle when a drawback valve is used. 10...Liquid, 10a...φ liquid level, 11...
Container, 12.14...Transfer passage, 13...Opening/closing valve,
15...Dripping nozzle, 15a...Opening, 16...
- Pressurized container, 17... First gas introduction pipe, 18... Three-way solenoid valve, 19... Second gas introduction pipe, 20... Gas discharge pipe, 21... Control device, Ao, Bo...close drive signal, A+, B1...open drive signal, b...compression time, C...dropping time, d...drawback time

Claims (1)

[Claims] (1) In a method in which the liquid stored in a container is dripped from a dripping nozzle through a transfer passage, after applying pressure in the container by a pressurizing means, the liquid in the container and the liquid in the container are By opening an on-off valve provided between the dripping nozzle and the dripping nozzle located at a higher position than the surface, the liquid starts dripping from the dripping nozzle,
A method for dropping a liquid, characterized in that while the on-off valve is being driven to open, pressurization of the pressurizing means is released to finish dropping the liquid, and then the on-off valve is driven to close.