Dilute solution manufacturing apparatus

Abstract

The present invention provides a kind of dilute solution manufacturing device, trace addition to the first liquid such as ultrapure water, the second liquid containing conductivity imparting substance or oxidation-reduction potential adjustment substance, can stably manufacture the dilute solution of specified concentration. Dilute solution manufacturing device by adding the second liquid containing at least one of conductivity imparting substance and oxidation-reduction potential adjustment substance to the first liquid to manufacture the dilute solution of the second liquid, wherein, with: first pipe (1), flow through the first liquid;Pump (6), via second pipe (5) to the first pipe (1) inside the second liquid is added;Degassing pipe (8), from the pump (6) degassing;Water quality sensor (11), by conductivity meter, resistivity meter or oxidation-reduction potential meter is constituted;And control device (12), when the water quality detection value of the water quality sensor (11) is above the specified value, open degassing valve (9).

Description

TECHNICAL FIELD

[0001] The present application relates to a dilute solution manufacturing apparatus that adds a second liquid containing an electric conductivity-imparting substance or an oxidation-reduction potential adjusting substance to a first liquid such as ultrapure water in a small amount to manufacture a dilute solution of the substance. BACKGROUND

[0002] As a cleaning solution used in wafer processing in the field of electronics industry, a solution in which an electric conductivity-imparting substance or an oxidation-reduction potential adjusting substance is added to ultrapure water is used.

[0003] At this time, the electric conductivity-imparting substance or the oxidation-reduction potential adjusting substance is added to ultrapure water with a pump (Patent Documents 1 and 2).

[0004] In the case where the electric conductivity-imparting substance or the oxidation-reduction potential adjusting substance is a substance that is easily vaporized, bubbles of the substance are easily accumulated in the pump. In particular, a pump of extremely low flow rate is easily clogged by bubbles, and when bubbles are accumulated, the pump cannot discharge a constant amount.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-171610;

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-206998. SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] An object of the present application is to provide a dilute solution manufacturing apparatus that adds a second liquid containing an electric conductivity-imparting substance or an oxidation-reduction potential adjusting substance to a first liquid such as ultrapure water in a small amount, and that can stably manufacture a dilute solution of a prescribed concentration.

[0011] TECHNICAL SOLUTION TO THE PROBLEM

[0012] The dilute solution manufacturing apparatus of the first application is a dilute solution manufacturing apparatus that manufactures a dilute solution of a second liquid by adding the second liquid containing at least one of an electric conductivity-imparting substance and an oxidation-reduction potential adjusting substance to a first liquid, characterized in that, in the dilute solution manufacturing apparatus that has a first pipe through which the first liquid flows, a pump that adds the second liquid to the first pipe through a second pipe, and a degassing mechanism that degasses the pump, a water quality detector composed of a conductivity meter, a resistivity meter, or an oxidation-reduction potential meter is provided at a position in the first pipe that is located on the downstream side of a connection portion of the second pipe, and a degassing mechanism control mechanism that operates the degassing mechanism when a water quality detection value of the water quality detector changes by a prescribed value or more is provided.

[0013] The dilute solution manufacturing device of the second invention is a dilute solution manufacturing device that manufactures a dilute solution of a second liquid by adding the second liquid containing at least one of a conductive property-imparting substance and a redox potential adjusting substance to a first liquid, characterized in that, in the dilute solution manufacturing device provided with a first pipe through which the first liquid flows, a pump that adds the second liquid to the first pipe through a second pipe, and a degassing mechanism that degasses the pump, a flow meter is provided at a position in the second pipe that is located on a downstream side of the pump, and a degassing mechanism control mechanism that operates the degassing mechanism when a detected value of the flow meter changes by a prescribed value or more.

[0014] In one aspect of the invention, a tank that stores the second liquid is provided, the second pipe is connected to the tank, the degassing mechanism is provided with a degassing pipe that guides the second liquid mixed with gas from the pump to the tank, and a valve provided in the degassing pipe, and the control mechanism controls opening and closing of the valve.

[0015] In the invention, as the conductive property-imparting substance and the redox potential adjusting substance, ammonia, carbon dioxide, hydrogen peroxide, ozone, and the like are exemplified, but the invention is not limited to these.

[0016] Effects of the Invention

[0017] The dilute solution manufacturing device according to the invention, in a case where gas is accumulated in a pump that adds a second liquid to a first liquid such as ultrapure water, and the discharge amount of the pump decreases, or as a result of which, the conductivity, resistivity, or redox potential of the dilute solution changes by a prescribed value or more from a constant stable value, the degassing mechanism is operated to degas the pump, and thus the discharge amount of the pump is recovered. As a result, a dilute solution of a prescribed concentration can be stably supplied. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a configuration diagram of a dilute solution manufacturing device of an embodiment.

[0019] Figure 2 is a configuration diagram of a dilute solution manufacturing device of another embodiment.

[0020] Figure 3 is a configuration diagram of a dilute solution manufacturing device of a comparative example. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments will be described with reference to the drawings.

[0022] Figure 1 An embodiment of the first invention is shown.

[0023] The ultrapure water as the first liquid is sent to the use point via the first pipe 1 having the flow meter 2 and the valve 3, and in the way, the second liquid in the tank 4 is added thereto via the second pipe 5, the pump 6 and the flow regulating valve 7. The degassing pipe 8 is provided to return the second liquid containing the gas generated in the pump 6 to the tank 4. The degassing valve 9 is provided to the degassing pipe 8. The degassing valve 9 can be provided to the middle of the degassing pipe 8, or to the upstream end or the downstream end.

[0024] The solution of the aforementioned electrically conductive imparting substance or the oxidation-reduction potential adjusting substance is stored in the tank 4.

[0025] In the first pipe 1, the water quality sensor 11 as a water quality detecting meter constituted by a conductivity meter, a resistivity meter or an oxidation-reduction potential meter (ORP meter) is provided at a position more on the downstream side than the connection portion (merging portion) of the second pipe 5. The detection signal of the water quality sensor 11 is input to the control device (PLC (Programmable Logic Controller) in this embodiment) 12. The pump 6, the flow regulating valve 7 and the degassing valve 9 are controlled by the control device 12.

[0026] In the dilute solution manufacturing device thus constituted, at the time of stabilization, the ultrapure water flows at a certain flow rate in the first pipe 1, and the second liquid flows at a certain flow rate in the second pipe 5, and the dilute solution to which the second liquid of a prescribed concentration is added is sent to the use point.

[0027] When the gas separated from the second liquid such as ammonia, carbonic acid gas, hydrogen peroxide, ozone and air is stored in the pump 6, the discharge amount of the pump 6 decreases, and the detection value of the sensor 11 deviates from the constant stable value (the same value as the target value) by a prescribed amount or more (for example, 5% or more). In the case where such a water quality variation is detected, the control device 12 opens the degassing valve 9 for a prescribed time to return the second liquid mixed with the gas from the pump 6 to the tank 4, and after the prescribed time, the degassing valve 9 is returned to the closed state. Thereby, the discharge amount of the pump 6 is returned to the stable amount, and the ultrapure water containing the second liquid of the prescribed concentration is sent to the use point.

[0028] In the above description, the case where the sensor detection value is varied by 5% or more is exemplified, but it is not limited thereto. The variation value of the sensor detection value can be generally selected from the range of 1 to 10%, particularly 3 to 7%.

[0029] The same applies to the flow meter 13 in the embodiment of the second application described below.

[0030] Figure 2 An embodiment of the second application is shown. In this embodiment, the flow meter 13 is provided in the second pipe 5 at a position more on the downstream side than the pump 6 (in this embodiment, the downstream side of the flow regulating valve 7). The detection signal of the flow meter 13 is input to the control device 12.

[0031] When the flow rate detected by the flow meter 13 changes by more than 5% from a continuously stable value, the control device 12 opens the degassing valve 9 for a predetermined time to perform degassing. Other components and functions are the same as... Figure 1 Same; the same symbol indicates the same part.

[0032] In this embodiment, ultrapure water containing a second liquid of a specified concentration is stably delivered to the point of use.

[0033] Example

[0034] The following describes the embodiments and comparative examples.

[0035] [Example 1]

[0036] use Figure 1 The dilute solution manufacturing apparatus shown uses pump 6 to deliver 29% NH3 solution from tank 4 and add it to ultrapure water flowing through piping 1 at a rate of 60 L / min to produce a solution with a conductivity of 3 μS / cm. The sensor 11 used is a conductivity meter. Degassing valve 9 is opened for 5 seconds to degas the solution when the conductivity drops 5% from the set value, and then closed to return to normal operation. During this 30-day test, the conductivity detected by conductivity meter 11 did not decrease by more than 10% from the set value.

[0037] [Example 2]

[0038] Except for adding 29% NH3 solution at a conductivity of 1500 μS / cm, the experiment was conducted in the same manner as in Example 1. During this 30-day test, the conductivity, as measured by conductivity meter 11, did not decrease by more than 10% from the set value.

[0039] [Example 3]

[0040] Except that the ultrapure water flow rate was set to 3 L / min, the test was conducted in the same manner as in Example 1. During this 30-day test, the conductivity, as measured by conductivity meter 11, did not decrease by more than 10% from the set value.

[0041] [Example 4]

[0042] use Figure 2 The dilute solution manufacturing apparatus shown was used to add 29% NH3 solution at the same ultrapure water flow rate (60 L / min) and target conductivity (3 μS / cm) as in Example 1.

[0043] In this embodiment 4, the following control is performed: when the flow rate detected by the flow meter 13 is 0, the degassing valve 9 is opened for 5 seconds to degas, and then the degassing valve 9 is closed to restore the normal state. During this 30-day test, the conductivity detected by the conductivity meter 11 did not decrease by more than 10% from the set value.

[0044] [Example 5]

[0045] use Figure 1 The device contains a 60% H2O2 solution in tank 4, with an ultrapure water flow rate of 60 L / min. A redox potentiometer is used as sensor 11 to deliver H2O2-containing ultrapure water with a concentration of 0.5 ppb to the point of use. The control is as follows: when the redox potential detected by the redox potentiometer 11 decreases by 5% from the set value, the degassing valve 9 is opened for 5 seconds to degas, and then closed to return to normal operation.

[0046] During the 30-day test, the redox potential detected by the redox potentiometer 11 did not decrease by more than 10% from the set value.

[0047] [Example 6]

[0048] Except for adding H2O2 in ultrapure water at a concentration of 1000 ppb, the experiment was conducted in the same manner as in Example 5. During this 30-day experiment, the redox potential, as detected by redox potentiometer 11, did not decrease by more than 10% from the set value.

[0049] [Example 7]

[0050] Except for setting the ultrapure water flow rate to 3 L / min, the test was conducted in the same manner as in Example 5. During this 30-day test, the redox potential, as detected by the redox potentiometer 11, did not decrease by more than 10% from the set value.

[0051] [Example 8]

[0052] use Figure 2 The dilute solution manufacturing apparatus shown was operated in the same manner as in Example 5, delivering ultrapure water with an H2O2 concentration of 0.5 ppb at the same ultrapure water flow rate and target redox potential. In this Example 8, the degassing valve 9 was opened for 5 seconds to degas when the flow rate detected by the flow meter 13 reached 0, and then closed to return to normal operation. During this 30-day test, the redox potential detected by the redox potentiometer 11 did not decrease by more than 10% from the set value.

[0053] [Comparative Examples 1-3]

[0054] like Figure 3 As shown, except that the device omitting the degassing piping 8 and valve 9 was used, the devices were operated under the same conditions as in Examples 1 to 3. The time until the conductivity decreased by 10% of the set value was measured. The results are shown in Table 1.

[0055] [Comparative Examples 4-6]

[0056] As Figure 3 shown, in addition to using the device omitting the degassing pipe 8 and the valve 9, the same conditions as in Examples 5 to 7 were respectively operated. The time until the H2O2 concentration was reduced by 10% of the set value was measured. The results are shown in Table 1.

[0057] [Table 1]

[0058]

[0059] As is apparent from Table 1, according to the present application, it is possible to stably deliver ultrapure water containing NH3 or H2O2 at a prescribed dilute concentration to a use point.

[0060] Although the present application has been described in detail using specific embodiments, it is obvious to those skilled in the art that various changes can be made without departing from the intent and scope of the present application.

[0061] This application is based on Japanese Patent Application No. 2020-044474 filed on March 13, 2020, the content of which is incorporated herein by reference in its entirety.

[0062] Explanation of Reference Signs

[0063] 1 first pipe

[0064] 2 flow meter

[0065] 4 tank

[0066] 5 second pipe

[0067] 6 pump

[0068] 7 flow regulating valve

[0069] 8 degassing pipe

[0070] 9 degassing valve

[0071] 11 water quality sensor

[0072] 12 control device

[0073] 13 flow meter

Claims

1. An apparatus for producing a dilute solution, used to produce a dilute solution of a first liquid by adding a second liquid containing ammonia or hydrogen peroxide to the first liquid, characterized in that, In a dilute solution manufacturing apparatus comprising a first pipe through which the first liquid flows, a pump that adds the second liquid into the first pipe via a second pipe, and a degassing mechanism for degassing the pump. have: A conductivity meter is installed in the first piping at a position downstream of the connection point of the second piping. The degassing mechanism control mechanism activates the degassing mechanism when the change in the conductivity meter's detected value exceeds a predetermined value selected between 3% and 7%; and The tank for storing the second liquid, The second piping is connected to the tank. The degassing mechanism includes a degassing pipe and a valve disposed on the degassing pipe, the degassing pipe being used to guide the second liquid mixed with gas from the pump to the tank. The control mechanism controls the opening and closing of the valve.

2. An apparatus for producing a dilute solution, used to produce a dilute solution of a first liquid by adding a second liquid containing ammonia or hydrogen peroxide to the first liquid, characterized in that, In a dilute solution manufacturing apparatus comprising a first pipe through which the first liquid flows, a pump that adds the second liquid into the first pipe via a second pipe, and a degassing mechanism for degassing the pump. have: The flow meter is installed in the second piping at a position downstream of the pump; The degassing mechanism control mechanism activates the degassing mechanism when the flow meter's detected value changes by more than a predetermined value selected between 3% and 7%; and The tank for storing the second liquid, The second piping is connected to the tank. The degassing mechanism includes a degassing pipe and a valve disposed on the degassing pipe, the degassing pipe being used to guide the second liquid mixed with gas from the pump to the tank. The control mechanism controls the opening and closing of the valve.

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