JPH11160229A - Concentration measuring cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and correctly measure the concentration of a process liquid flowing in a process liquid feed pipe. SOLUTION: A concentration measuring cell 1 is provided with an inflow opening 2 through which a process liquid enters, an outflow opening 3 through which the process liquid flows out, a passage part 4 sending the process liquid between the inflow opening 2 and outflow opening 3, and a measurement light- passing part 5 formed at the passage part 4 to pass a measurement light SL for measuring the concentration of the process liquid through the process liquid flowing in the passage part 4. In order to measure the concentration of the process liquid which is a mixture of deionized water and one or more chemical solutions, the concentration measurement cell 1 is detachably installed in the middle of a process liquid feed pipe 30 where the process liquid flows, with the inflow opening 2 and outflow opening 3 positioned respectively at the upstream and downstream sides. A stirring part 6 for stirring the process liquid sent from the inflow opening 2 to the passage part 4 is set between the inflow opening 2 and the measurement light-passing part 5 in the passage part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the concentration of a processing solution obtained by mixing pure water and at least one type of chemical solution (concentration of the chemical solution in the processing solution), for example, used for substrate processing. The present invention also relates to a concentration measuring cell which is removably interposed in the middle of a processing liquid feed pipe through which the processing liquid flows.

[0002]

2. Description of the Related Art As shown in FIG. 11, a substrate processing apparatus for processing a substrate by using a processing solution obtained by mixing pure water and one or more chemicals mixes pure water with one or more chemicals. The processing liquid mixing section 10, a substrate processing section 20 for processing a substrate using the processing liquid mixed in the processing liquid mixing section 10, and a processing liquid mixed in the processing liquid mixing section 10 are sent to the substrate processing section 20. A liquid supply pipe 30 for treating liquid is provided.

In this type of apparatus, the concentration of the processing liquid supplied to the substrate processing section 20 is adjusted by feedback control, or the concentration of the processing liquid supplied to the substrate processing section 20 is monitored. The concentration of the processing liquid flowing in the liquid pipe 30 is measured.

In order to measure the concentration of the processing solution, a concentration measuring cell 100 is interposed in the middle of the processing solution feed pipe 30. A conventional concentration measuring cell 100 includes an inlet 101 for flowing a processing solution, an outlet 102 for flowing a processing solution,
A flow path portion 103 through which the processing liquid flows between the inflow port 101 and the outflow port 102, and a measurement light SL formed in the flow path section 103 for measuring the concentration of the processing liquid flows through the flow path section 103. And a measuring light transmitting unit 104 that transmits the processing liquid.

[0005] In a state where the concentration measuring cell 100 is interposed in the middle of the processing solution feed pipe 30, the measuring light transmitting section 1
A light projecting unit 41 that irradiates the measuring light SL onto the light receiving unit 04 and a light receiving unit 42 that receives the measuring light SL that has passed through the processing liquid flowing through the measuring light transmitting unit 104 are provided to face each other with the measuring light transmitting unit 104 interposed therebetween. The transmitted light received by the light receiving unit 42 is sent to the densitometer 40, and the concentration meter 40 calculates the concentration of the processing liquid based on the intensity (light amount) of the transmitted light received by the light receiving unit 42.

The concentration of the processing solution obtained by the concentration meter 40 is given to a controller 50. The controller 50 feeds back the concentration adjustment of the processing liquid supplied to the substrate processing unit 20 based on the concentration of the processing liquid supplied from the densitometer 40 so that the processing can be performed according to the processing condition (recipe) input from the input unit 55. The control is performed or the concentration of the processing liquid supplied to the substrate processing unit 20 is monitored.

[0007]

However, this type of processing liquid mixing section 10 mixes pure water and a chemical by introducing a chemical into pure water flowing through a mixing pipe 12. Then, the pure water and the chemical liquid are not sufficiently mixed in the mixing pipe 12 and flow out to the processing liquid supply pipe 30. On the other hand,
In the conventional concentration measuring cell 100, the processing liquid (the processing liquid in which pure water and the chemical solution are not sufficiently mixed) flowing from the inflow port 101 flows through the measuring light transmitting section 104 as it is. In some cases, the mixing ratio of the chemical solution in the processing liquid flowing through the liquid varies with time, and as shown in FIG. 12A, the concentration of the processing liquid obtained by the densitometer 40 may fluctuate and become unstable. Such a phenomenon is caused by the concentration measuring cell 10.
0 appears more prominently as the processing solution mixing unit 10 is disposed closer to the processing solution mixing unit 10.

Further, as shown in FIG. 12B, for example, due to the arrangement of the processing liquid feed pipe 30, the processing liquid is sent between the processing liquid mixing section 10 and the concentration measuring cell 100. In the case where the bent portion 31 or the like is formed in the liquid tube 30, due to the uneven flow of the processing liquid flowing through the processing liquid liquid feeding tube 30,
As shown in FIG. 12C, the concentration of the processing solution obtained by the densitometer 40 may be further shifted from the actual concentration.

As described above, if the concentration of the processing liquid is not stably and accurately obtained by the densitometer 40, the controller 50 monitors the concentration of the processing liquid supplied to the substrate processing unit 20 when monitoring the concentration of the processing liquid. It is not possible to correctly determine whether the current concentration of the processing liquid is within the appropriate range, and it becomes impossible to prevent the occurrence of processing defects and the like. When the concentration of the processing solution supplied to the substrate processing unit 20 is adjusted by feedback control based on the concentration of the processing solution provided from the densitometer 40, the controller 50 adjusts the introduction flow rate of the chemical solution introduced into the mixing pipe 12. However, if the concentration of the processing liquid is not stably and accurately obtained by the densitometer 40, the control performed by the controller 50 on the processing liquid mixing section 10 is improper. As a result, the mixing ratio of the chemical liquid to the pure water in the processing liquid, that is, the concentration of the processing liquid becomes large, and uniform processing cannot be performed.

The present invention has been made in view of such circumstances, and is not affected by the interposition position of the concentration measuring cell and the arrangement state of the processing liquid feed pipe, and the like. It is an object of the present invention to provide a concentration measurement cell capable of stably and accurately measuring the concentration.

[0011]

The present invention has the following configuration in order to achieve the above object. That is, the present invention provides an inflow port for inflow of the processing liquid, an outflow port for outflow of the processing liquid, a flow path section for flowing the processing liquid between the inflow port and the outflow port, and a flow path formed in the flow path section. A measurement light transmitting section for transmitting measurement light for measuring the concentration of the processing liquid into the processing liquid flowing through the flow path section.
In order to measure the concentration of the processing liquid mixed with more than one type of chemical liquid, in the middle of the line of the processing liquid supply pipe through which the processing liquid flows, the inlet is on the upstream side, and the outlet is on the downstream side. In the concentration measurement cell that is detachably interposed, a stirring unit that stirs the processing liquid that has flowed from the inflow port into the flow path unit, the inflow port in the flow path unit and the measurement light transmission unit, It is characterized by being provided between.

[0012]

The operation of the present invention is as follows. A concentration measuring cell is interposed in the middle of the processing liquid feed pipe through which a processing liquid in which pure water and one or more chemical liquids are mixed is flowed, with the inlet being on the upstream side and the outlet being on the downstream side. You. Since the concentration measurement cell according to the present invention is provided with a stirrer that stirs the processing liquid that has flowed into the flow channel from the flow inlet, between the flow inlet and the measurement light transmitting unit in the flow channel, The processing liquid flowing through the processing liquid supply pipe and flowing into the flow path from the inlet is agitated by the agitation unit and then flows to the measurement light transmitting unit. Therefore,
Even if the processing liquid in which the pure water and the chemical liquid are not sufficiently mixed is introduced into the flow path from the inlet, when the pure water and the chemical liquid are sufficiently mixed when flowing into the measurement light transmitting section. In other words, the concentration of the processing liquid can be stably and accurately measured without being affected by the position of the concentration measurement cell and the arrangement of the processing liquid supply pipe.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an example of a substrate processing apparatus to which a concentration measuring cell according to the present invention is applied.

This substrate processing apparatus is a batch type apparatus provided with a processing tank 21 for immersing a plurality of substrates W in a processing liquid and simultaneously processing the substrates. The overall configuration is as described with reference to FIG. The processing liquid mixed in the processing liquid mixing unit 10 that mixes pure water and one or more types of chemicals is sent to the substrate processing unit 20 via the processing liquid feed pipe 30, and the substrate processing unit 20
Using the processing liquid sent from the processing liquid mixing unit 10, the substrate W
Is configured to be processed.

The processing liquid mixing section 10 includes a pure water supply pipe 11 and a mixing pipe 12. The mixing pipe 12 is a pure water supply pipe 1
1 and a processing solution feed pipe 30 are interposed between the pipes 11 and 30 so as to connect the pipes 1 and 30 to each other. The pure water supply pipe 11 is provided with a pure water supply valve 13, and by operating the pure water supply valve 13, the supply of pure water to the mixing pipe 12 and the stop thereof are switched. When pure water is supplied to the mixing tube 12, the supply flow rate of pure water is always constant. A chemical solution supply pipe 15 is connected to the mixing pipe 12 via a chemical solution introduction valve 14, and by operating each of the chemical solution introduction valves 14, the introduction and stop of each chemical solution into the mixing pipe 12 is switched. Each chemical solution introduction valve 14 is configured, for example, as a flow rate control valve that can arbitrarily adjust the flow rate, and is configured so that the flow rate of the chemical solution introduced into the mixing pipe 12 can be appropriately adjusted. Thereby, in the mixing tube 12, pure water and one or more kinds of chemicals can be mixed at an arbitrary mixing ratio,
The concentration of the processing solution (the concentration of the chemical solution in the processing solution) can be arbitrarily changed.

The controller 50 operates the pure water supply valve 13 and each chemical liquid introduction valve 14 in accordance with the processing conditions (recipe) input from the input unit 55, and converts the pure water and one or more specified chemical liquids. A processing liquid mixed at a specified mixing ratio (processing liquid concentration) is supplied to the substrate processing section 20, a pure water alone is supplied to the substrate processing section 20 as a processing liquid, or a processing liquid (pure water and chemical liquid) is supplied. The control for stopping the supply to the substrate processing unit 20 is performed in a designated processing order. At this time,
The concentration of the processing liquid flowing out of the processing liquid mixing unit 10 and flowing into the processing liquid feed pipe 30 is measured by the densitometer 40, and the measured value (the current processing liquid flowing through the processing liquid feed pipe 30) is measured. Based on the concentration, for example, the controller 50 controls the operation amount of the chemical solution introduction valve 14 by feedback control so as to obtain the designated concentration, and after the concentration of the processing liquid is adjusted to the designated concentration. And monitor whether it is maintained at that concentration.

Processing tank 21 provided in substrate processing section 20
Has a processing liquid injection pipe 22 attached to the lower part of the tank.
The processing liquid feed pipe 30 and the processing liquid injection pipe 22 are connected, and the processing liquid is supplied from the processing liquid injection pipe 22 into the processing tank 21 so that a rising liquid flow of the processing liquid can be formed in the processing tank 1. It is configured. Then, the excess processing liquid in the processing tank 1 overflows from the upper part of the processing tank, and is collected and discharged in the overflow tank 23 provided on the outer peripheral upper part of the processing tank 1, whereby the processing liquid in the processing tank 1 is discharged. Substitution can also be performed.

FIG. 2 shows an example of the configuration of a single wafer type substrate processing apparatus. The substrate processing unit 20 of this apparatus spins one substrate W in a horizontal position and rotates the substrate W about a vertical axis, and ejects a processing liquid to the substrate W held by the spin chuck 25. A nozzle 26 for supply is provided.

In the apparatus shown in FIG. 2, the state in which the processing liquid flowing through the processing liquid feed pipe 30 flows to the nozzle 26 and the state in which the processing liquid flows to the drain 27 near the nozzle 26 of the processing liquid feed pipe 30 are switched. A possible switching valve 28 is provided. At the time of non-processing, the switching valve 28 is switched to the drainage drain 27 side, and only the pure water is flowing out of the processing liquid mixing unit 10, and the pure water flowing through the processing liquid feed pipe 30 is discharged to the drainage drain 27. It is flowing to. Then, when mixing the pure water and the chemical solution, the controller 50 performs feedback control based on the concentration of the processing solution from the densitometer 40, for example, to the concentration specified by the recipe input from the input unit 55. Thus, the operation amount of the chemical solution introduction valve 14 is adjusted and controlled. When the concentration of the processing liquid reaches the specified concentration, the processing liquid of the concentration is switched from the concentration measurement position to the switching valve 2.
After a lapse of a sufficient time required to reach No. 8, the switching valve 28 is switched to the nozzle 26 side, and the processing liquid having a predetermined concentration is jetted and supplied from the nozzle 26 to the substrate W to process the substrate W. Then, for example, the controller 50
While ejecting and supplying the processing liquid from 6 to the substrate W, it is monitored whether or not the concentration of the processing liquid is maintained at the specified concentration. When the supply time of the processing liquid from the nozzle 26 to the substrate W elapses, the switching valve 28 is switched to the drainage drain 27 side, and the chemical liquid introduction valve 14 is operated so as to stop the introduction of the chemical liquid into the mixing tube 12. Return to the non-processing state described above.

In the apparatus shown in FIGS. 1 and 2, in order to measure the concentration of the processing liquid flowing through the processing liquid feed pipe 30 with the concentration meter 40, the concentration is measured in the middle of the processing liquid feed pipe 30. Cell 1 is interposed.

As shown in FIGS. 1 to 3, the concentration measuring cell 1 according to the present invention includes an inlet 2 through which a processing solution flows,
An outlet 3 for flowing the processing liquid, a flow path 4 for flowing the processing liquid between the inlet 2 and the outlet 3, and a measuring light formed in the flow path 4 for measuring the concentration of the processing liquid. A measurement light transmitting section 5 for transmitting the SL into the processing liquid flowing through the flow path section 4; and a stirring section (specifically, a stirring section for stirring the processing liquid flowing into the flow path section 4 from the inflow port 2). The configuration 6 will be described later) 6 is provided between the inflow port 2 in the flow path unit 4 and the measurement light transmitting unit 5. FIG. 3A is an enlarged front view of the concentration measuring cell according to one embodiment of the present invention, FIG. 3B is a longitudinal sectional view seen from the front, and FIG. FIG. 3A is a cross-sectional view taken along line AA of FIG. In FIG. 3 and subsequent figures, the flow of the processing liquid is indicated by a two-dot chain line arrow.

The concentration measuring cell 1 is provided with joints 7a and 7b at the end on the inlet 2 side and the end on the outlet 3 side, respectively. It is configured so that it can be interposed freely. When the concentration measuring cell 1 is interposed in the middle of the processing liquid feed pipe 30, the inlet 2
On the upstream side (processing liquid mixing section 10) side and the outlet 3 on the downstream side (substrate processing section 20) side.

The cell 1 for concentration measurement shown in FIG. 1 is configured such that the diameter of the flow path portion 4 is larger than the diameter of the processing liquid feed pipe 30. When the diameter of the flow path section 4 is substantially larger, the diameter of the flow path section 4 may be substantially the same as that of the processing liquid feed pipe 30, that is, the entire concentration measuring cell 1 may be formed of a cylindrical pipe.

A cylindrical concave portion 4a is formed on the outer peripheral surface of the flow path portion 4.
Are formed so as to face each other. A region having a relatively small width d sandwiched between the bottom surfaces 4b of the concave portions 4a is defined as a measurement light transmitting portion 5. In the densitometer 40, depending on the absorption amount of the measuring light SL in the processing liquid when transmitting through the processing liquid (the intensity of the transmitted light transmitted through the processing liquid).
I want the concentration of the processing solution. Therefore, if the width d of the measurement light transmitting portion 4 is too wide, the absorption amount of the measurement light SL becomes too large, and the concentration of the processing liquid cannot be measured. Therefore, the width d of the measurement light transmitting portion 4 is made relatively narrow. It is configured as follows. The width (distance between the bottom surfaces 4b) d of the measurement light transmitting portion 4 and the thickness t of each bottom surface 4b are manufactured to have predetermined dimensions.

In a state where the concentration measuring cell 1 is interposed in the middle of the processing solution feed pipe 30, one of the two recesses 4a has a measuring light transmitting portion 5 for measuring. Light SL
Is provided, and the other concave portion 4 is provided.
a, a light receiving unit 42 for receiving the measurement light SL transmitted through the processing liquid flowing through the measurement light transmitting unit 5 is provided, and the light projecting unit 41 and the light receiving unit 42 face each other with the measurement light transmitting unit 5 interposed therebetween. Be deployed. The transmitted light received by the light receiving unit 42 is sent to the densitometer 40, and the concentration meter 40 calculates the concentration of the processing liquid based on the intensity (light amount) of the transmitted light received by the light receiving unit 42.

In FIG. 3, a tip of an optical fiber 43 for guiding a predetermined amount of measurement light SL from a light source (not shown) provided in the densitometer 40 and an optical fiber 44 for guiding transmitted light to the densitometer 40 are shown. The distal end is attached to each recess 4a by a mounting jig (not shown) or the like, and the irradiation end of the optical fiber 43 is set to the light projecting section 41 and the incident end of the optical fiber 44 is set to the light receiving section
Although the number is 2, the light projector and the light receiver may be directly attached to each of the recesses 4a, and the photoelectric conversion result of the transmitted light received by the light receiver may be given to the densitometer 40 by an electric signal.

The bottom surface 4b of the concave portion 4a in the flow path portion 4
Portion through which the measuring light SL passes (measuring light passing portion 4c)
The other parts are made of a light-transmitting material (for example, quartz or sapphire) or a non-light-transmitting material (chemical-resistant material) as long as the material is resistant to chemicals in the processing liquid flowing through the flow path unit 4. Resin material having a property). On the other hand, the measurement light passing portion 4c has chemical resistance to a chemical solution in the processing liquid flowing through the flow path portion 4 and has a light-transmitting material (for example, quartz or sapphire) for transmitting the measurement light SL.
It is formed with. When the measurement light passing portion 4c is eroded by the chemical solution and the thickness t changes, the absorption amount of the measurement light SL in the measurement light passing portion 4c changes with time. It cannot be realized. Therefore, it is preferable that at least the measurement light passage portion 4c is formed of sapphire or the like which is translucent and has high chemical resistance. Alternatively, the measurement system may be calibrated by flowing pure water to correct the fluctuation over time.

Next, a specific configuration of the stirring section 6 will be described with reference to FIGS. FIG. 4 shows a punching plate 61 in which a number of small holes 61a are formed as shown in FIG. 4A, which is arranged between the inflow port 2 in the flow path unit 4 and the measurement light transmitting unit 5. This is an example in which the stirring unit 6 is configured. According to this configuration, a part of the processing liquid flowing into the flow path unit 4 from the inflow port 2 is
When the flow is changed by hitting a part other than 1a and merges with the processing liquid passing through the small holes 61a, the entire processing liquid is stirred, and the pure water and the chemical liquid are mixed before flowing into the measurement light transmitting unit 5. Become.

Note that, as shown in FIG.
A plurality of punching plates 61 may be provided between the inflow port 2 and the measurement light transmitting section 5 along the flow direction of the processing liquid flowing into the flow path section 4 from the inflow port 2. When a plurality of punching plates 61 are provided, for example, as shown in FIGS. 4C and 4D, the positions of the small holes 61 a of each punching plate 61 are shifted when viewed from the inlet 2. In such a case, the processing liquid can be more reliably stirred.

Each of the members 62 to 65 shown in FIGS.
Similarly, between the inflow port 2 and the measurement light transmitting section 5 in the flow path section 4, along the flow direction of the processing liquid flowing into the flow path section 4 from the inflow port 2, each member 62- A plurality of 65s may be provided.

FIG. 5 shows that a rectifying member 62 having a rectifying plate 62a as shown in FIG.
This is an example in which the agitating unit 6 is configured by being disposed between the agitating unit 6 and the agitating unit 6. According to this configuration, the flow of the processing liquid that has flowed into the flow path unit 4 from the inflow port 2 is rectified by each rectifying plate 62 a, and the entire processing liquid is agitated during the rectification before flowing into the measurement light transmitting unit 5. The pure water and the chemical are mixed together. When a plurality of rectifying members 62 are provided, for example, as shown in FIGS. 5C and 5D, the rectifying direction of the rectifying plates 62 a of each rectifying member 62 is viewed from the inlet 2. It may be the same (FIG. 5C) or may be changed for each rectifying member 62. Further, as shown in FIG. 5E, as viewed from the inflow port 2, the rectifying plates 65 a of the respective rectifying members 65.
May be arranged to be shifted.

FIG. 6 shows an example in which an agitator 6 is formed by rotatably mounting an impeller 63 between the inflow port 2 in the flow path 4 and the measurement light transmitting section 5. is there.
The impeller 63 is rotatably attached to a fixed member 63b supported and fixed by a rod-shaped member 63a in the flow path unit 4. According to this configuration, the impeller 63 is rotated by the flow of the processing liquid flowing into the flow path unit 4 from the inflow port 2, and the processing liquid is agitated by the rotation of the impeller 63. Before flowing, the pure water and the chemical solution are mixed. FIG. 6C shows the blade plate 6.
3 is an example of a configuration in which a plurality of 3s are provided.

FIG. 7 shows an example in which the agitating section 6 is configured by disposing a torsion plate 64 between the inflow port 2 in the flow path section 4 and the measuring light transmitting section 5. According to this configuration, a swirling flow is formed in the processing liquid that has flowed into the flow path unit 4 from the inflow port 2 and is agitated, and the pure water and the chemical liquid are mixed before flowing into the measurement light transmitting unit 5. . As shown in FIG. 7B, the use of a perforated torsion plate 64 in which a number of small holes 64a are formed in the torsion plate 64 allows the processing liquid to be stirred more reliably. FIG. 7 illustrates the torsion plate 64 in which the plate member is twisted by about 180 °.
° or more (eg, 360 °) twisted torsion plate 64
May be used, and a plurality of torsion plates 64 may be provided along the flow direction of the processing liquid flowing into the flow path unit 4 from the inflow port 2.

FIG. 8 shows a swirling flow forming member 65 having a large number of wing-like members 65a for forming a swirling flow as shown in FIG. This is an example in which the agitating unit 6 is configured by being disposed between the agitating unit 6 and the agitating unit 6. The wing-shaped members 65a are radially attached to the core member 65a such that the flow path forming direction SY of each wing-shaped member 65a is inclined with respect to the axial direction JY of the core member 65b. Te The swirling flow forming member 65 is disposed in the flow channel portion 4 such that the axial direction JY of the core member 65a is substantially parallel to the flow direction of the processing liquid flowing into the flow channel portion 4 from the inflow port 2. Has been established. According to this configuration, similarly to the torsion plate 64 of FIG. 7, a swirling flow is formed in the processing liquid that has flowed into the flow path unit 4 from the inflow port 2 and is agitated. Water and chemicals will be mixed. When a plurality of swirling flow forming members 65 are provided, for example, as shown in FIG.
(65af) and the swirl flow forming member 65 in the subsequent stage.
The arrangement direction of the wing-like members 65a (65ab) may be shifted.

FIG. 10 shows a filling 66 such as a quartz ball,
This is an example in which a stirring unit 6 is configured by being disposed between the inflow port 2 in the flow path unit 4 and the measurement light transmitting unit 5. Filling 6
Reference numeral 6 is disposed between the inflow port 2 in the flow path unit 4 and the measurement light transmitting unit 5 by a net 66a or the like. According to this configuration,
The processing liquid flowing into the flow path unit 4 from the inflow port 2 is filled with the filler 66.
The pure water and the chemical solution are mixed before flowing into the measurement light transmitting section 5 while passing through the measuring light transmitting section 5.

Note that, for example, the agitation unit 6 may be configured by appropriately combining the respective configurations of FIGS. 4 to 8 and FIG. 10, such as disposing a filler 66 at a stage subsequent to the punching plate 61.

As described above, by using the concentration measuring cell 1 according to this embodiment, the processing liquid in which the pure water and the chemical solution are not sufficiently mixed is supplied from the inlet 2 of the concentration measuring cell 1. Even if it flows into the flow path part 4,
When the treatment liquid is stirred by the stirring unit 6 upstream of the measurement light transmission unit 5 and flows into the measurement light transmission unit 5, the pure water and the chemical solution are sufficiently mixed. The concentration of the processing liquid can be measured stably and accurately without being affected by the position, the arrangement state of the processing liquid supply pipe 30, and the like. It is possible to accurately and stably monitor the concentration of the processing solution based on the control, and adjust the concentration of the processing solution by feedback control.

The present invention is not limited to the shape of the density measuring cell 1 described in the above embodiment, but can be applied to various shapes of density measuring cells. For example, the concentration measuring cell 1 of the above-described embodiment has a shape in which the flow path 4 is circular in cross section as viewed from the inlet 2, but the flow path 4 is rectangular in cross section as viewed from the inlet 2. The present invention can be similarly applied to a concentration measuring cell or the like.

Further, the concentration measuring cell 1 according to the present invention comprises:
The present invention is not limited to the apparatus having the configuration shown in FIGS. 1 and 2 and may be applied to any substrate processing apparatus using a processing liquid obtained by mixing pure water and one or more chemicals.

[0040]

As is apparent from the above description, according to the present invention, the stirring section for stirring the processing liquid flowing into the flow path from the inlet is provided with the inlet in the flow path and the measuring light transmitting section. Therefore, even if the processing liquid in which the pure water and the chemical liquid are not sufficiently mixed is flowed into the flow path from the inflow port, when the pure water and the chemical liquid flow into the measurement light transmitting part, the pure water and the chemical liquid are not mixed. This means that the concentration of the processing solution can be measured stably and accurately without being affected by the position of the concentration measurement cell and the arrangement of the processing solution feed pipe. it can. Therefore, if the concentration measuring cell according to the present invention is used, processing concentration monitoring of the processing liquid performed based on the measured concentration of the processing liquid flowing in the processing liquid supply pipe, concentration adjustment of the processing liquid by feedback control, and the like can be performed with high accuracy. It can be performed stably.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an example of a substrate processing apparatus to which a cell for concentration measurement according to the present invention is applied.

FIG. 2 is a diagram showing a configuration of another example of the substrate processing apparatus to which the concentration measuring cell according to the present invention is applied.

FIG. 3 is an enlarged front view, a vertical cross-sectional view as viewed from the front, and a cross-sectional view taken along the line AA of the concentration measuring cell according to one embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of an example of a stirring unit.

FIG. 5 is a diagram illustrating a configuration of another example of the stirring unit.

FIG. 6 is a diagram illustrating a configuration of still another example of the stirring unit.

FIG. 7 is a diagram illustrating a configuration of still another example of the stirring unit.

FIG. 8 is a diagram showing a configuration of still another example of the stirring unit.

9 is a diagram showing a configuration of a swirling flow forming member used in the configuration example of FIG.

FIG. 10 is a diagram showing a configuration of still another example of the stirring unit.

FIG. 11 is a diagram showing a configuration of a conventional cell for concentration measurement and a schematic configuration of a substrate processing apparatus to which the cell is applied.

FIG. 12 is a view for explaining a problem of a conventional cell for concentration measurement.

[Explanation of symbols]

1: Cell for concentration measurement 2: Inflow port 3: Outflow port 4: Flow path section 5: Measurement light transmission section 6: Stirring section 10: Processing liquid mixing section 20: Substrate processing section 30: Processing liquid supply pipe 40: Concentration Total 50: Controller 55: Input unit 61: Punching plate 62: Rectifying member 63: Impeller 64: (perforated) torsion plate 65: Swirling flow forming member 66: Filling material SL: Measurement light W: Substrate

Claims (1)

[Claims] 1. An inlet for inflowing a processing liquid, an outlet for outflowing a processing liquid, a flow path for flowing a processing liquid between the inlet and the outlet, and formed in the flow path. A measurement light transmitting unit that transmits measurement light for measuring the concentration of the processing liquid into the processing liquid flowing in the flow path unit, and a processing liquid obtained by mixing pure water and at least one chemical liquid. In order to measure the concentration, in the middle of the treatment liquid feed pipe through which the treatment liquid flows, the inlet is located upstream and the outlet is located downstream so that the concentration can be detachably mounted. In the cell, a concentration section provided with a stirrer for stirring the processing liquid flowing into the flow path section from the inflow port, between the inflow port and the measurement light transmission section in the flow path section. Measurement cell.