JPH04157357A - Automatic fluid controlling apparatus - Google Patents

Abstract

PURPOSE:To follow fluid ingredients which are changing by measuring potentials when reagents of amounts corresponding to the upper and lower limits in terms of management of concentration of pre-specified processing fluid are put in respectively by oxidation-reduction potential electrodes. CONSTITUTION:An active ingredient amount of processing fluid sampled by a sampling means 100 is obtained by oxidation-reduction potential(ORP) electrodes 19, 20 from change in potential by titration, and these respective means are controlled by a control means 102. When oxidation-reduction potential of the processing fluid is measured, a six-way solenoid valve 4 is switched from a path A to a path B, and a constant amount of the processing fluid is led to either of reaction cells 17, 18 by switching of a three-way solenoid valve 8. Reagents of amounts corresponding to the upper and lower limits in an oxidation-reduction potential range of the pre-specified processing fluid are added to the processing fluid to measure the oxidation-reduction potential by the electrodes 19, 20. Since it is compared with a pre-specified reference potential, it is easy to detect whether it is within a set range thereby permitting the control.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an automatic liquid management device suitable for managing the amount of components in a processing liquid for semiconductor manufacturing.

"Prior Art" Conventionally, stripping solutions (processing solutions) used, for example, in semiconductor manufacturing processes, have been analyzed and managed using various methods. Management has been automated.

As an example of this type of automatic liquid management device, in the device previously proposed by the present inventor (Japanese Patent Application No. 2-38713), a stripping liquid containing a mixture of sulfuric acid and hydrogen peroxide is applied online using a pump or the like. After that, the sampled stripping solution is measured with an absorbance meter to control its degree of deterioration, and the stripping solution is supplied to a reaction cell in an analytical instrument, and the redox potential is measured by an electrode in this reaction cell. Potentiometric titration analysis is performed to detect the concentration of active ingredients in the stripping solution.

In such an analysis, a computer installed in the control unit controls the operation of equipment such as pumps and valves, and also determines the sulfuric acid concentration in the treated liquid based on the amount of the titrated reagent dripped into the reaction cell. , the hydrogen peroxide concentration was calculated, and the calculation results were output to CR'1' or a printer.

"Problem to be Solved by the Invention" By the way, in the above-mentioned automatic liquid management device, when performing potentiometric titration analysis, a change in potential is detected after a certain amount of reagent is injected, and then a change in potential is detected according to the amount of change. A method is adopted in which the next injection amount is determined and the titration is repeated again.

However, when potentiometric titration is performed by repeating titration-potential measurement-titration in this way, the titration time takes too much time, making it impossible for titration analysis to follow changes in the concentration of the treated solution, making it difficult to manage the treated solution quickly. I am dissatisfied with not being able to do it.

"Means for Solving the Problem" Therefore, the automatic liquid management device of the present invention includes a sampling means for sampling the processing liquid, a detection means for determining the amount of active ingredients in the sampled processing liquid from a potential change by titration, and and a control means for controlling each means, wherein the detection means comprises an oxidation-reduction potential electrode, and when a spear reagent corresponding to a preset upper and lower limit value for concentration of the processing liquid is introduced. The control means is provided with a treatment liquid management function that measures the potentials of each with redox potential electrodes and compares these measured values with a preset reference potential, so that the redox potential of the treatment liquid can be set in advance. The above-mentioned problem was solved by detecting whether it was within the specified range and managing the processing liquid.

"Function" According to the automatic liquid management device of the present invention, the processing liquid management function adds reagents in amounts corresponding to the upper and lower limits of the preset redox potential range of the processing liquid to the processing liquid, The oxidation-reduction potential of the processing liquid is measured with the oxidation-reduction potential electrode and compared with a preset reference potential, so it is easy to detect whether the concentration of the processing liquid is within the preset range. becomes possible.

"Embodiment" An embodiment of the present invention will be described with reference to FIGS. 1 to 3. This embodiment is an example in which the present invention is applied to a resist processing liquid (stripping liquid) management device.

First, the general structure of the entire automatic liquid management apparatus will be described with reference to FIG. 1(A). In FIG. 1(A), reference numeral 1 denotes a processing liquid supply path through which processing liquid is supplied from the processing tank along the illustrated path.

Here, examples of the processing liquid include a sulfuric acid-hydrogen peroxide aqueous solution that peels off and dissolves a resist made of novolak resin or the like on a semiconductor silicon wafer.

A cooler 2, a pump 3, and a hexagonal solenoid valve 4 are sequentially arranged in this processing liquid supply path 1.

The six-way solenoid valve 4 has one port 4a connected downstream of the processing liquid supply path 1, and is connected to the path A indicated by the solid line in FIG.
and route B indicated by a broken line, and is normally set to take route A. In addition, a sampling pipe 5 is provided between the ports 4b and 4e of the six-way solenoid valve 4, and a sampling pipe 5 is provided to connect the ports 4b and 4e, and the port 4C is used to send out the sample (processing liquid) in the sampling pipe 5. For example, a pump 6 for pumping pure water
A pressure feeding path 7 is connected thereto.

Here, the sampling pipe 5 has a predetermined value m of the processing liquid stored therein, and is used for quantitative determination.

Furthermore, a flow path 9 connected to the three-way solenoid valve 8 is connected to the port 4d of the six-way solenoid valve 4, and a flow path 11 connected to the three-way solenoid valve IO is connected to the port 4r. The three-way solenoid valve 10 is connected to a return path 12 that connects to a processing tank (path shown) and a drain path 14 that connects to a drain tank 13, and with this configuration, the water is led out from the six-way solenoid valve 4. The processing liquid is returned to the processing tank or guided to the drain tank 13.

The three-way solenoid valve 9 has a first measurement path 15 and a second measurement path 1.
A first reaction cell 17 is provided in the first measurement path 15, and a second reaction cell 18 is provided in the second measurement path I6.

These reaction cells 17 and 18 have an ORP as a sensor for titration analysis, which determines the amount of active ingredient in the processing liquid sampled in each cell from the change in potential caused by titration.
(oxidation-reduction potential) electrodes 19.20 are provided, and a discharge channel 21.2 for discharging the titrated sample at the bottom of the cell.
2 are arranged. A solenoid valve 23, 24 is disposed in each of the discharge passages 21, 22, and a pump 25 is disposed after the discharge passages 21, 22 merge, and a pump 25 is disposed in the discharge passage 21, 22. is the drain passage 14
is merging with. Here, the sample after titration in the reaction cell 17.18 falls under its own weight by opening the solenoid valve 23.24 and is guided to the drain path 14 via the confluence path 26, or is forced by the pump 25. is led to the drain passage 14. In addition, when draining by the pump 25, a liquid level sensor may be installed in the drain tank 13, and the timing of draining may be determined based on a signal from the liquid level sensor.

Furthermore, a first reagent tube 27 is provided in the first reaction cell 17.
and a second reagent tube 28 are arranged with one end facing each other, and a third reagent tube 2 is disposed in the second reaction cell 18.
9 is placed with one end facing out. These numbers! ,
The second and third reagent tubes 27, 28, and 29 have titration pumps 30a, 30b, and 30c disposed in their respective channels, and a reagent bottle 31a disposed at the end thereof,
31b, 31c to titration pumps 30a, 30b,
30c supplies a constant m of reagent into the reaction cell 17 or 18. In addition, reagent bottle 3
1a contains potassium permanganate (KMnO) as a reagent.
, ), sulfuric acid (H, So, ) is contained in the reagent bottle 31b, and sodium hydroxide (NaOH) is contained in the reagent bottle 31c.

In an automatic liquid management device having such a configuration, normally the hexagonal solenoid valve 4 is routed to route the processing liquid to the sampling pipe 5 and the flow path 11. It is returned to the processing tank (path shown) through the return path 12, or led to the drain tank 13 through the drain path 14 by switching the three-way solenoid valve 10.

On the other hand, when measuring the oxidation-reduction potential of the processing liquid, the processing liquid remaining in the sampling pipe 5 when the processing liquid is passed through the above-mentioned path A is transferred to the pressure feeding path 7 by switching to path B.
By sending out more pure water, it is pushed out and guided to the flow path 9. Then, by appropriately switching the three-way solenoid valve 8, a certain amount of processing liquid is introduced into either of the reaction cells 17 and 18. Here, in the reaction cell 17, a certain amount of potassium permanganate is supplied from the reagent bottle 31a and the reagent bottle 31b, that is, an amount stoichiometrically equivalent to the lower limit of the preset redox potential range of the treatment liquid. A standard solution and a constant amount of a standard solution of sulfuric acid are supplied and their redox potentials are measured. Furthermore, in this reaction cell 17, a standard solution of potassium permanganate in an amount stoichiometrically equivalent to the difference between the upper and lower limits of the preset redox potential range of the processing liquid and a certain amount of sulfuric acid were added. A standard solution is provided and its redox potential is measured. Through such measurements, it is detected whether the redox potential of the processing liquid is within a preset redox potential control range.

Furthermore, after such a measurement is completed, the solenoid valve 23 or 24 is opened, and the treated liquid after the measurement flows into the confluence path z6.
It is guided to the drain tank 13 through the drain tank 13.

In addition, in the above configuration, FIG.
The configuration in the range indicated by 00 is used as the sampling means.

Further, in FIG. 1(B), the reference numeral 102 is a control means, and this control means 102 includes an input means 103 such as a keyboard, and a CIt 'l' display for displaying the operating status, processing status, etc. of the apparatus. output means 104 (for example, the first
A system diagram similar to that shown in Figure (A) is shown, a display panel with lamps etc. is provided at locations corresponding to each component), and as described above, the upper limit of the oxidation-reduction potential range of the processing liquid is set in advance. Processing solution management in which an amount of reagent stoichiometrically corresponding to the value and the lower limit value is added to the processing solution, and the redox potential of the processing solution is measured at the above redox potential and compared with a preset reference value. A function 105 is built-in.

The control means IQ2 controls the following processing means (1') based on the input data of the human power means 10'A, and also controls the processing means (P) based on the control result of this processing means (P). The detection means obtained by controlling (Q
) Based on the detected data, the display panel 104 displays the operating status and processing status.

The processing means (P) includes a cooler 2, a six-way solenoid valve 4, a three-way solenoid valve 10, titration pumps 31a, 31b,
3tc, N solenoid valve 23.24, pump 25, etc.
In addition, as the detection means (Q), □ n P 11:L
There are poles 20 and 21.

Next, the control contents of the automatic liquid management device stored in the control means 102 will be explained with reference to FIGS. 2 and 3.

FIG. 2 is a diagram for explaining the flow of this automatic liquid management device. Note that "step n" in the specification refers to r in FIG.
Corresponds to sPnJ.

Step 1> Using the input means 103, set the management range of the oxidation-reduction potential of the processing liquid for analysis, that is, its upper limit value 81 and lower limit value at, and also set the reference value (reference potential) VO of the measured potential. Set. Here, the reference value V. Finally, set the potential between the potential when the highest amount of reagent corresponding to the upper limit of concentration is added to the processing solution and the potential when the amount of reagent corresponding to the lower limit is added. be done.

Step 2> Set the six-way solenoid valve 4 to the path shown by the solid line in FIG. It is supplied into the first reaction cell 17 and the inside thereof is cleaned.

Furthermore, by switching the three-way solenoid valve 9, the second reaction cell 18 is similarly cleaned. Note that during this time, the processing liquid supplied from the processing liquid supply path I is transferred to the sampling pipe 5.
It is guided to the flow path 11 side via.

Step 3> The electromagnetic valve 23 is set to an open state and the pump 25 is driven to discharge the cleaning liquid in the reaction cell 17 to the drain tank 13 via the confluence channel 26. Further, the cleaning liquid inside the reaction cell 18 is drained in the same manner.

Step 4> Set the six-way solenoid valve 4 to the path, and connect the sampling pipe 5.
A predetermined amount of the processing liquid filled in the sampling pipe 5 is then passed through the flow path 9 and the three-way solenoid valve 8 to the reaction cell 17 (
g).

<Step 5> From ORr-' electrode 19 (20) i, reaction cell +7
Measure the potential Vl of the treatment liquid before injecting the titrant in (18).

<Step 6> Drive the titration pumps 30a and 30b, and add the standard solution in an amount (A1) stoichiometrically equivalent to the lower limit of the control range of the redox potential of the treatment liquid set in step 1. is injected into the reaction cell 17.

Step 7> The ORP electrode 19 measures the potential of the processing liquid in the reaction cell 17.

Step 8> The titration pumps 30a and 30b are driven to bring the oxidation-reduction potential of the treatment liquid to the upper limit of the control range set in step 1.
Add the standard solution to the reaction cell 17 in an amount equivalent to the difference between the upper limit and the lower limit, so that the amount of the standard solution injected in step 6 becomes the stoichiometrically equivalent N(At). Inject inside.

Step 9> The potential V of the processing liquid in the reaction cell 17 is measured by the ORP electrode 19.

Step 10 > Potential V measured in step 6 and step 8,
From V, the potential of the sampled initial processing solution ■1
Determine whether or not it is within the set management range. (3rd
This will be described later with reference to the drawings. ) <Step II> Output the judgment at step IO and display the judgment on the display panel +114.

Step 12> In the same manner as in Step 3, the processing liquid in the reaction cell 17 is discharged.

Step +3> Determine whether or not to continue sampling and managing the processing liquid, that is, whether or not to perform continuous operation. If YES, return to step 2 and repeat the operation; if NO, repeat the operation. It becomes S'r OP.

Next, a flow for determining whether the potential of the processing liquid is within the set control range, that is, whether the processing liquid is within the set control concentration range will be described with reference to FIG.

Step 10-1> The oxidation-reduction potential of the sampled processing liquid is the reference value V of the measurement potential set in Step I. If it is YES, proceed to step 10-2 and proceed to step 10-2.
In this case, the process proceeds to step l0-3.

<Step 10-2> Compare the potential V of the treatment solution measured in Step 7, in which an amount of the standard solution stoichiometrically equivalent to the lower limit of the control range of the redox potential is injected, and vo. , the curve in Figure 4 (
As shown in 1), if V≧vo, it is determined that the concentration of the sampled processing liquid is below the lower limit, and the process proceeds to step 1O-4, where the curve (Il) in FIG.
, (I[I), if V≧Vo is not satisfied, the process proceeds to step 10-5.

Step 10-3> Drain the liquid and return to step 2 above.

Step 10-4> In step 11, it is output (displayed) that the concentration of the processing liquid is below the lower limit of the control range.

Step 10-5> The Tri position V of the treatment solution into which the standard solution of m, which stoichiometrically corresponds to the upper limit of the control range of the redox potential measured in Step 9, is injected. If vJ≧■o as shown in the curve ([1) in FIG. Proceed to the curve in Figure 4 (
As shown in I[l], if ■3≧Vo, it is determined that the concentration of the processing liquid is greater than the limit value ``1'', and step 10-7
Proceed to.

Step 10-6> In step 11, it is output (displayed) that the processing liquid is within the control range.

Step 10-7> In step II, it is output (displayed) that the processing liquid is above the upper limit of the control range.

In such an automatic liquid management device, the processing liquid management function 105 processes reagents in amounts stoichiometrically corresponding to the upper and lower limits of the preset redox potential range of the processing liquid. In addition to the treatment liquid, the redox potential of the treatment liquid is measured with a redox potential electrode and compared with a preset reference value,
This makes it easy to detect whether the concentration of the processing liquid is within a preset range, which is much easier than the conventional method of directly measuring the concentration and managing the processing liquid based on the measured value. The state of the processing liquid can be managed quickly, making it possible to follow the ever-changing liquid components on an automatic processing line. Furthermore, since the amount of titration reagent used is always constant, the timing of addition of liquid is clear, and the management of the apparatus itself becomes easy. Furthermore, the apparatus can be simplified because it is only necessary to detect whether the liquid concentration is within the control range without directly analyzing the liquid concentration.

In addition, an absorbance measurement mechanism such as an absorbance meter is provided between the pump 3 and the hexagonal solenoid valve 4 in the processing liquid supply path l in FIG. Deterioration of activity due to dissolution may be detected.

In addition, although the above example shows a case in which the treatment liquid is a sulfuric acid-hydrogen peroxide aqueous system, it may also be applied to other treatment liquids such as a hydrochloric acid-hydrogen peroxide aqueous system or an ammonia-hydrogen peroxide aqueous system. Of course you can do it too.

"Effects of the Invention" As explained above, the automatic liquid management device of the present invention uses the processing liquid management function to supply reagents in amounts corresponding to the upper and lower limits of the preset redox potential range of the processing liquid. is added to the processing solution, and the redox potential of the processing solution is measured with a redox potential electrode and compared with a preset reference potential, thereby determining whether the concentration of the processing solution is within a preset range. Since we have made it possible to easily detect the concentration, it is possible to control the condition of the processing liquid much faster than when directly measuring the concentration and managing the processing liquid based on the measured value as in the past. Therefore, it is possible to follow the ever-changing liquid components on an automatic processing line, and highly reliable liquid management can be performed. Furthermore, since the amount of titration reagent used is always constant, the timing of addition of liquid is clear, and the management of the apparatus itself becomes easy. Furthermore, since it only detects whether or not it is within the control range without directly analyzing the 'am degree, the equipment can be simplified, making it possible to make the equipment smaller and lower in price. can.

[Brief explanation of drawings]

FIG. 1(A) to FIG. 3 are diagrams showing one embodiment of the automatic liquid management device of the present invention, in which FIG. 1(A) is an overall schematic configuration diagram, and FIG. 1(B) is a control device. FIG. 2 is a flowchart showing the main flow of the device, FIG. 3 is a flowchart showing the processing liquid management function in the control means of the device,
FIG. 4 is a graph for supplementary explanation of the flow of determining whether the processing liquid is within the control concentration range by the processing liquid management function. 19.20...ORP electrode (oxidation-reduction potential electrode) 100...Sampling means 102...Control means 105...Processing liquid management function.

Claims (1)

[Scope of Claims] An automated system comprising sampling means for sampling the processing liquid, detection means for determining the amount of active ingredients in the sampled processing liquid from changes in potential due to titration, and control means for controlling each of these means. The liquid management device is characterized in that the detection means includes an oxidation-reduction potential electrode, and the detection means is configured to oxidize the potential when an amount of reagent corresponding to a preset upper limit and lower limit of the concentration of the processing liquid is added. An automatic liquid management device characterized in that the control means is provided with a processing liquid management function that measures the reduction potential with an electrode and compares these measured values with a preset reference potential.