JP6895925B2 - Liquid flow meter - Google Patents

Description

The present invention relates to a liquid flow meter that controls the flow rate of a chemical solution used in a chemical solution discharge system by a pressurizing method.

In the chemical discharge system based on the pressurization method, the chemical is pressurized and supplied by _{N 2 from a canister or the like, so that N 2} is dissolved in the chemical. _{Therefore, N 2} dissolved in a narrow part in the pipe such as a regulating valve of a liquid flow meter and a bent part is bubbled due to the influence of a pressure drop.

When bubbles come out from the nozzle during the edge bead rinse (EBR) process used in the photoengraving process, the bubbles burst and the chemical solution scatters, resulting in an abnormality in the resist pattern. In this case, when an abnormality in the resist pattern is found, it takes time and effort to perform the regeneration process, that is, redoing. On the other hand, when no abnormality in the resist pattern is found, there is a problem that the yield of the product is lowered.

For example, Patent Document 1 discloses a processing apparatus as a chemical discharge system by a pressurizing method. In the processing device, a sackback valve that changes the flow rate is installed in the middle of the rinse liquid supply pipe, and a degassing pipe is provided downstream of the sackback valve. An air operation valve for discharging air bubbles is provided. This prevents the treatment liquid from scattering due to air bubbles and improves the yield of the product.

Japanese Unexamined Patent Publication No. 7-283184

However, in the technique described in Patent Document 1, since it is necessary to separately provide a degassing tube, there is a problem that the chemical liquid discharge system becomes large.

Therefore, an object of the present invention is to provide a technique capable of discharging generated bubbles and sending a chemical solution containing no bubbles to the downstream side without increasing the size of the chemical discharge system.

The liquid flow meter according to the present invention has a casing having a liquid inlet port for the chemical liquid to flow in and a liquid discharge port for the chemical liquid to flow out, and a first chemical liquid liquid provided in the casing and communicating with the liquid inlet port. A storage chamber, a second chemical storage chamber provided in the casing and communicating with the liquid discharge port, a first chemical storage chamber and a second chemical storage chamber provided in the casing and communicating with the liquid discharge port. The second chemical storage chamber is provided with a connection pipe for connecting the two, and a flow control valve arranged in the connection pipe. It has an internal space that can be stored and is connected to a drain mechanism that can discharge the air bubbles that have accumulated in the internal space.

According to the present invention, since the liquid flow meter used in the chemical solution discharge system has a function of accumulating bubbles of gas dissolved in the chemical solution and discharging the accumulated bubbles, it is not necessary to separately provide a degassing tube. As a result, the generated air bubbles can be discharged and the chemical solution containing no air bubbles can be sent to the downstream side without increasing the size of the chemical liquid discharge system.

It is sectional drawing of the liquid flow meter which concerns on embodiment. It is a piping diagram of the chemical liquid discharge system provided with the liquid flow meter which concerns on embodiment.

<Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the liquid flow meter 11 according to the embodiment.

The liquid flow meter 11 is a float type flow meter, and is a casing 1, a liquid inlet port 1a, a liquid discharge port 1b, a first chemical liquid storage chamber 1c, a connection pipe 1d, a second chemical liquid storage chamber 1e, and a flow rate adjusting valve 2. It has. The liquid flow meter 11 also includes a liquid level detection sensor 11a, which will be described later in a modified example of the embodiment.

The liquid entry port 1a is a connection portion connected to a canister 8 (see FIG. 2) filled with the chemical liquid, and the chemical liquid flows in from the canister 8. The liquid discharge port 1b is a connection portion connected to the discharge nozzle 12 (see FIG. 2), and the chemical liquid flows out to the discharge nozzle 12. Both the liquid inlet port 1a and the liquid discharge port 1b are provided on the side portion of the casing 1, and the liquid inlet port 1a is provided below the liquid discharge port 1b.

The first chemical solution storage chamber 1c is provided inside the lower part of the casing 1 and communicates with the liquid inlet port 1a at the lower end portion of the first chemical solution storage chamber 1c. The second chemical storage chamber 1e is provided inside the upper part of the casing 1 and communicates with the discharge port 1b at the lower end of the second chemical storage chamber 1e.

The connection pipe 1d is provided inside the casing 1 slightly above the central portion in the vertical direction, and connects the first chemical solution storage chamber 1c and the second chemical solution storage chamber 1e. That is, the first chemical solution storage chamber 1c and the second chemical solution storage chamber 1e communicate with each other via the connecting pipe 1d. The flow rate adjusting valve 2 is a needle valve type adjusting valve and is arranged in the connecting pipe 1d. Therefore, the chemical liquid flowing in from the liquid inlet port 1a passes through the first chemical liquid storage chamber 1c, the connection pipe 1d, and the second chemical liquid storage chamber 1e in this order, and flows out from the liquid discharge port 1b.

The second chemical storage chamber 1e on the downstream side of the flow rate adjusting valve 2 has an internal space 3 having a cross-sectional area larger than the cross-sectional area of the connecting pipe 1d. The internal space 3 has a size capable of accumulating the gas bubbles 6 dissolved in the chemical solution. Specifically, the internal space 3 has a diameter more than twice the diameter of the connecting pipe 1d. That is, the internal space 3 has a cross-sectional area that is four times or more the cross-sectional area of the connecting pipe 1d. The gas dissolved in the chemical solution is N ₂ .

In the liquid flow meter 11 configured in this way, when the chemical solution passes through the portion blocked by the flow rate adjusting valve 2, the flow velocity of the chemical solution becomes high. As the flow velocity increases, as explained by Bernoulli's theorem, the static pressure decreases, and the static pressure decreases below the saturated vapor pressure, so that the gas dissolved in the chemical solution becomes bubbles. When the chemical solution containing the bubbles 6 passes through the internal space 3, the bubbles 6 are lighter than the chemical solution, so that they move upward and are stored in the upper part of the internal space 3.

A waste liquid pipe 5 having an air operation valve 4 is connected to the upper end of the second chemical storage chamber 1e, and when the air operation valve 4 is opened, air bubbles 7 accumulated in the internal space 3 pass through the air operation valve 4. Is discharged to the waste liquid pipe 5. The air operation valve 4 corresponds to a drain mechanism capable of discharging air bubbles 7 accumulated in the internal space 3.

Next, a chemical discharge system including the liquid flow meter 11 will be described. FIG. 2 is a piping diagram of a chemical liquid discharge system including the liquid flow meter 11 according to the embodiment.

As shown in FIG. 2, the chemical discharge system includes a canister 8, a pressure regulator 9, a trap tank 10, a liquid flow meter 11, a discharge nozzle 12, air operation valves 4, 14, 15 and a discharge control system 13. There is.

The canister 8 is filled with a chemical solution, and the inside of the canister 8 is pressurized by the pressure regulator 9. The liquid inlet port 1a of the liquid flow meter 11 is connected to the canister 8 via the trap tank 10. The trap tank 10 is connected to the waste liquid pipe 5 via an air operation valve 15. The liquid discharge port 1b of the liquid flow meter 11 is connected to the discharge nozzle 12 via the air operation valve 14.

The discharge control system 13 controls the air operation valves 4 and 14, and opens the air operation valve 14 to discharge the chemical liquid from the discharge nozzle 12. The trap tank 10 is provided with a liquid level detection sensor 10a for detecting that the chemical liquid in the canister 8 has run out. The liquid level detection sensor 10a detects whether or not the chemical solution in the canister 8 has run out by detecting, for example, the amount of the chemical solution flowing into the trap tank 10 from the canister 8.

The discharge control system 13 is connected to the liquid level detection sensor 10a by wiring, and when the liquid level detection sensor 10a detects that the chemical solution in the canister 8 has run out, the air operation valve 4 can be opened. In other words, the discharge control system 13 can open the air operation valve 4 by determining the timing at which the chemical solution is not flowing. By opening the air operation valve 4, the air bubbles 7 accumulated in the internal space 3 can be discharged to the waste liquid pipe 5. As a result, the chemical solution containing no bubbles 6 flows out from the discharge port 1b and is discharged from the discharge nozzle 12.

As described above, in the liquid flow meter 11 according to the embodiment, the second chemical solution storage chamber 1e can store the gas bubbles 6 dissolved in the chemical solution having a cross-sectional area larger than the cross-sectional area of the connecting pipe 1d. It was connected to an air operation valve 4 having an internal space 3 and capable of discharging air bubbles 7 accumulated in the internal space 3.

Therefore, since the liquid flow meter 11 used in the chemical solution discharge system has a function of accumulating the gas bubbles 6 dissolved in the chemical solution and discharging the accumulated bubbles 7, it is not necessary to separately provide a degassing tube. As a result, the generated bubbles 6 can be discharged and the chemical solution containing no bubbles 6 can be sent to the downstream side without increasing the size of the chemical discharge system.

Even if there is a portion on the downstream side where the flow velocity is likely to change, the dissolved gas bubbles 6 are removed, so that the chemical solution is difficult to form bubbles.

The liquid inlet port 1a is connected to the canister 8 filled with the chemical solution via the trap tank 10, and the trap tank 10 is provided with a liquid level detection sensor 10a for detecting that the chemical solution in the canister 8 has run out. The operation valve 4 operates so as to discharge the air bubbles 7 accumulated in the internal space 3 when the chemical solution in the canister 8 runs out. Therefore, it is possible to prevent the chemical solution from being discharged together with the bubbles 7.

<Modified example of the embodiment>
Next, a modified example of the embodiment will be described. In the above, the air operation valve 4 operates so as to discharge the air bubbles 7 accumulated in the internal space 3 when the chemical liquid in the canister 8 runs out, but instead of this, the air bubbles 7 accumulated in the internal space 3 are discharged. When the amount of bubbles 7 exceeds a predetermined amount, the bubbles 7 accumulated in the internal space 3 may be discharged.

As shown in FIG. 1, the liquid level detection sensor 11a is provided in the second chemical liquid storage chamber 1e of the liquid flow meter 11, and determines the height position of the liquid level of the chemical liquid stored in the second chemical liquid storage chamber 1e. By detecting, the amount of bubbles 7 accumulated in the internal space 3 is detected. Specifically, the amount of the bubbles 7 is detected on the assumption that the bubbles 7 are accumulated in the entire internal space 3 above the liquid surface of the chemical solution. The liquid level detection sensor 11a may be provided outside the second chemical storage chamber 1e of the liquid flow meter 11 instead of inside the second chemical storage chamber 1e.

As shown in FIGS. 1 and 2, the discharge control system 13 is connected to the liquid level detection sensor 11a by a wiring 13a. The discharge control system 13 opens the air operation valve 4 for a set time when the amount of air bubbles 7 accumulated in the internal space 3 exceeds a predetermined amount. When the set time elapses, the discharge control system 13 closes the air operation valve 4. Here, the discharge control system 13 opens the air operation valve 4 on condition that the air operation valve 14 is closed.

As a result, the bubbles 7 accumulated in the internal space 3 can be discharged at any time, so that the bubbles 7 accumulated in the internal space 3 are further suppressed from being mixed with the chemical solution and discharged from the discharge nozzle 12 via the discharge port 1b. it can.

In the present invention, the embodiments can be appropriately modified or omitted within the scope of the invention.

1 Casing, 1a Inlet port, 1b Outlet port, 1c 1st chemical storage chamber, 1d connection piping, 1e 2nd chemical storage chamber, 2 Flow control valve, 4 Air operation valve, 8 Canister, 10 Trap tank, 10a, 11a Liquid level detection sensor.

Claims (3)

A casing having an inlet port for the chemical liquid to flow in and a liquid discharge port for the chemical liquid to flow out.
A first chemical storage chamber provided in the casing and communicating with the liquid inlet port, and
A second chemical storage chamber provided in the casing and communicating with the liquid discharge port.
A connection pipe provided in the casing and connecting the first chemical solution storage chamber and the second chemical solution storage chamber, and
The flow control valve arranged in the connection pipe and
With
The second chemical solution storage chamber has an internal space having a cross-sectional area larger than the cross-sectional area of the connecting pipe and capable of accumulating gas bubbles dissolved in the chemical solution, and the bubbles accumulated in the internal space. A liquid flow meter connected to a drain mechanism that can drain the gas. The liquid inlet port is connected to the canister filled with the chemical liquid via a trap tank.
The trap tank is provided with a liquid level detection sensor that detects that the chemical solution in the canister has run out.
The liquid flow meter according to claim 1, wherein the drain mechanism operates so as to discharge the air bubbles accumulated in the internal space when the chemical solution in the canister runs out. A liquid level detection sensor for detecting the amount of air bubbles accumulated in the internal space by detecting the height position of the liquid level of the chemical liquid contained in the second chemical liquid storage chamber is further provided.
The liquid according to claim 1, wherein the drain mechanism operates so as to discharge the bubbles accumulated in the internal space when the amount of the bubbles accumulated in the internal space becomes equal to or more than a predetermined amount. Flowmeter.

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