JPH10296067A - Solution diluting device, method for adjusting solution concentration and method for forming pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the titration accuracy of a first solution at a high level by measuring the concentration of a second solution periodically (wherever desired) to seek an equivalent point in the mixing of the second and a third solution and titrating the first solution using the second solution again, based on the measurement results, when diluting the first solution with pure water. SOLUTION: This solution diluting device titrates (a first titration process) a diluted developer 13a by using a sulfuric acid reagent (a second solution) 15a, then titrates a NaOH solution (a third solution) by using a sulfuric acid reagent 15a before or after the first titration process, when developer 11 for a positive type resist (an alkaline solution; the first solution) is diluted with a high-purity water 12. Further, the device measures (a second titration process) a change in the concentration of the sulfuric acid reagent 15a over time periodically (whenever desired) to seek an equivalent point in the mixing of the sulfuric acid reagent 15a with the NaOH solution (the third solution) 16a. Next, the concentration is measured at a high accuracy level and again the first titration process is carried out with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution diluting apparatus for adjusting the concentration of a solution to be titrated while titrating the concentration of the solution to be titrated with the solution to be titrated, a method for adjusting the solution concentration, and a pattern forming method.

[0002]

2. Description of the Related Art It can be said that the manufacture of a semiconductor integrated circuit comprises repetitive steps of photoetching and impurity diffusion. The important photoetching here is supported by high quality photoresist. This photoresist is used, for example, as a hard mask for always drawing a fine and accurate pattern on a wafer. For example, an ultraviolet light resist using a novolak resin as a positive type (solubilizing type) resist is frequently used. Have been.

The operation of forming a pattern by using such a positive resist is shown in FIGS. Here, first, after applying a resist film P2 on the upper surface of the substrate P1, masking P3 is performed thereon, and ultraviolet rays P4 are irradiated as shown in FIG. 6 to change the structure of a part (P2a) of the resist film P2. Then, it is solubilized by the solvent (positive developer) 1. As the positive developer 1, an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) is used.

In general, the chemical formula of the dissolution reaction between an aqueous alkali solution as a developing solution 1 and a novolak resin which is one of the constituents of a resist is as follows.

[0005]

Embedded image

Here, the OH ions are supplied from a positive developer (aqueous alkaline solution), and this amount is closely related to the concentration of the positive developer. That is, in the developing step using an alkaline aqueous solution, an alkaline aqueous solution (positive developer)
If the temperature and density of the film change, the finished dimensions change, and therefore the development rate changes. In consideration of this, it is necessary to control the density to a required level (2.380 ± 0.003%) in order to obtain a required finished size. Therefore, for such a purpose, it is important for the mixing operation of the developer to accurately mix the developer while checking the concentration of the developer with a solution diluting device.

In a conventional solution diluting apparatus, as shown in FIG. 8, when a positive type resist developing solution 1 before dilution and ultrapure water 2 are lightly mixed at a predetermined ratio in a dilution tank 3, they are mixed. The developer 1 is sent to an automatic neutralization titration analyzer 4 and titrated with a sulfuric acid reagent 5 to calculate the concentration of the developer 1. Then, based on the calculated concentration, in order to satisfy the target concentration measurement accuracy, the developer 1 or the ultrapure water 2 is re-charged into the dilution tank 3, and the automatic neutralization titration analyzer 4 and the sulfuric acid reagent 5 are again supplied.
Measure the concentration with. By repeating the procedure of such a procedure several times, the concentration of the developer 1 is appropriately adjusted, and the adjusted developer 1 is stored in the supply tank 6.

[0008]

Here, in order to perform accurate measurement by the conventional method, it is assumed that the concentration of the sulfuric acid reagent 5 is stable. However, the actual concentration of the sulfuric acid reagent 5 changes with time due to, for example, moisture aggregating on a shoulder or the like in a container that stores the sulfuric acid reagent 5, and it is difficult to maintain the initial concentration. In such a case, as a result of titrating the developing solution 1 using sulfuric acid shifted from the initial concentration, the concentration of the developing solution 1 shifted from the true value is indicated. If the deviation from the true value is smaller than the required accuracy of the density measurement of the developer 1, no problem arises.
As in the case of the developing solution 1, the allowable range of the concentration measurement accuracy is narrow, and 2.3.
In the case of about 80% ± 0.003%, if the sulfuric acid concentration measurement accuracy changes by 0.1% or more with respect to the reference concentration (for example, 0.1N), the concentration measurement of the developer 1 calculated from the changed sulfuric acid concentration Accuracy deviates from an acceptable range.

Therefore, by taking some measures to prevent the sulfuric acid concentration from changing, or by correcting the amount of change from the initial concentration even if the concentration changes, the accurate concentration can be determined at the time of using sulfuric acid for titration. Need to be

[0010] In view of the above problems, the present invention improves the accuracy of concentration measurement when measuring the concentration of a dilute solution calculated from the titration solution in titration of a diluting solution (solution to be titrated) such as a developer. It is an object of the present invention to provide a solution diluting device, a solution concentration adjusting method, and a pattern forming method.

[0011]

According to a first aspect of the present invention, there is provided a first tank for adding pure water to a predetermined first solution to dilute the first solution, the first tank being diluted with the first solution. For measuring the concentration of the second solution by obtaining a second tank in which a second solution for performing titration is previously stored, and an equivalent point in mixing with the second solution. Third
A third tank in which the solution is stored in advance, and measuring the concentration of the second solution by obtaining an equivalent point in mixing the second solution and the third solution, and measuring the concentration of the second solution. And a neutralization titration analyzer for titrating the first solution diluted with the second solution based on the concentration of the second solution.

[0012] In the invention described in claim 2, the third tank is configured to store the third solution every time the concentration of the second solution is measured.
This is a replaceable container that is disposed and replaced together with the solution.

According to a third aspect of the present invention, a first tank for adding pure water to a predetermined first solution to dilute the first solution and titrating the diluted first solution are performed. A second tank in which a second solution is stored in advance, a hydrometer for measuring the concentration of the second solution, and a concentration of the second solution measured by the hydrometer. , A neutralization titration analyzer for titrating the first solution diluted with the second solution.

According to a fourth aspect of the present invention, the fourth solution is made of the same material as the second solution and has a higher concentration than the second solution.
Further comprising a fourth tank in which the solution is stored in advance, wherein the neutralization titration analyzer drops the fourth solution in an initial stage in the titration operation of the first solution, and the first solution And both the second solution and the fourth solution can be selectively switched so that the second solution is dropped in the latter half of the titration operation.

According to a fifth aspect of the present invention, the second solution is a sulfuric acid reagent having a concentration of less than 0.1N, and the fourth solution has a concentration of 0.1N or more and 1.0N or less. It is a sulfuric acid reagent.

According to a sixth aspect of the present invention, the solution diluting apparatus further includes a weighing scale for measuring the weight of the first tank, wherein the first tank is provided with the diluted tank contained therein. A lightweight material having a specific gravity as light as possible for the first solution is used.

According to a seventh aspect of the present invention, the first solution is a developing solution used in a resist process in a process of manufacturing a semiconductor device, and the second solution has a hydrogen ion concentration lower than a neutralization point. It is a highly acidic reagent.

[0018] In addition, in the invention according to claim 8, the third solution is an alkaline reagent having a hydrogen ion concentration lower than the neutralization point.

According to a ninth aspect of the present invention, the diluted first
A solution concentration adjusting method in which the concentration of the solution is adjusted while titrating with a predetermined second solution that causes a concentration change over time, using the second solution in an initial state before the concentration change. A first step of diluting and adjusting the first solution to a desired concentration while repeatedly titrating the first solution, a part of the first solution adjusted to the desired concentration and the second step And a second step of measuring a change in the concentration of the second solution from the amounts of the two solutions introduced at that time.

According to a tenth aspect of the present invention, the first solution is a developing solution used in a resist process in a process of manufacturing a semiconductor device, and the second solution has a hydrogen ion concentration lower than a neutralization point. It is a highly acidic reagent.

According to the present invention, a first pattern forming step of applying a resist on an upper surface of a predetermined substrate;
A second pattern forming step of masking above the resist, a third pattern forming step of changing a part of the structure of the resist by irradiating ultraviolet rays, and developing a part of the resist having changed structure with alkaline A fourth pattern forming step of solubilizing with a liquid, wherein a concentration of the diluted developer is changed over time to a predetermined value as a step prior to the fourth step. The method further includes a solution concentration adjusting step of adjusting while titrating with an acidic reagent. Then, the solution concentration adjusting step comprises repeatedly titrating the first solution using the second solution in an initial state before a concentration change occurs.
A first step of diluting and adjusting the solution to a desired concentration, and collecting and neutralizing a part of the first solution and a part of the second solution adjusted to the desired concentration, respectively. And a second step of measuring a change in the concentration of the second solution from the introduction amounts of the two solutions at that time.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

<< First Embodiment >><Structure> The solution diluting apparatus according to the first embodiment of the present invention
Is diluted with ultrapure water. In particular, the first reagent is subjected to a concentration analysis (first titration process) by titrating a second reagent different from the first reagent to perform a dilution process. Is to execute. More specifically, when diluting a positive resist developing solution (alkali solution: first reagent) with ultrapure water, the solution diluting apparatus uses a sulfuric acid reagent (second (First reagent)), and before and after this first titration, the sulfuric acid reagent is titrated against the NaOH solution (third reagent). Then, a change in the concentration of the sulfuric acid reagent over time is periodically measured (second titration process), the concentration is adjusted with high accuracy, and then the above-described first titration process is executed with high accuracy. ing.

FIG. 1 is a diagram showing a solution diluting apparatus. As shown in FIG. 1, the solution diluting apparatus is used to measure and mix a positive resist developing solution (alkaline solution) 11 and ultrapure water 12 at a predetermined ratio in a dilution tank 13 as shown in FIG.
The dilution process is performed while measuring the concentration of the mixed diluted developer 13a to a predetermined value. The dilution tank 13 is used for both the first titration process and the second titration process. And a sulfuric acid reagent 15 in the automatic neutralization titration analyzer 14.
a NaOH container 16 for introducing a NaOH solution 16a to the automatic neutralization titration analyzer 14
And

The dilution tank 13 is placed on a weighing scale 19, and the dilution of the developing solution 11 and the ultrapure water 12 is performed while observing the measured value of the weighing scale 19. In order to improve weighing accuracy at this time, FRP (fiber reinfoced
Light materials such as plastic) are used.

As shown in FIG. 2, the automatic neutralization titration analyzer 14 performs a concentration analysis by titrating one of the reagents to the other reagent.
3a or the NaOH solution 16a) is introduced from the first introduction pipe 21 or the second introduction pipe 22 to measure and store the liquid, and the other reagent (that is, the sulfuric acid reagent 15a) to the third
Burette 25 which is introduced from the introduction pipe 24 of the weighing medium
A titration cell 26 for accommodating one of the reagents measured by the measuring tube 23 and titrating the other reagent through the burette 25; and a glass for measuring the acid-base frequency (pH) of the mixed solution in the titration cell 26. A pH electrode 27 such as an electrode pH meter, a valve controller 29 for controlling the valve 28 of the burette 25 to be turned off when an equivalent point is detected at the pH electrode 27, and a valve controller 29 for detecting the equivalent point. A concentration calculation display section 30 is provided for calculating and displaying the concentration of one of the reagents (that is, the diluted developer 13a or the NaOH solution 16a) based on the reagent.

Here, the first introduction pipe 21 is connected to the dilution tank 1
3, and the diluted developer 13a therein is introduced,
The second introduction pipe 22 is connected to the NaOH container 16 to
An OH solution 16a is introduced. In addition, the third introduction pipe 24
Is connected to the sulfuric acid tank 15 and the sulfuric acid reagent 15a is introduced.

By switching between the first introduction pipe 21 and the second introduction pipe 22 according to the designation of the operator, the automatic neutralization titration analyzer 14 can use the sulfuric acid reagent 15a with respect to the diluted developer 13a. The first function of titration and the sulfuric acid reagent 15
a and the second function of appropriately mixing the NaOH solution 16a.

Here, the NaOH container 16 stores N
In order to avoid a change in the concentration of aOH, a disposable package (replaceable container) is used, which is kept sealed until the seal is opened at the time of use. In addition, since it is disposable, the capacity of the NaOH container 16 is reduced to a necessary minimum amount in order to avoid wasteful disposal of the NaOH solution 16a.

Further, the pH electrode 27 for determining the equivalent point is used.
A known general device may be used. For example, the device is configured to measure the amount of change in the case where the measurement of the potential difference in the internal circuit changes according to the change in the electrical characteristics of the solution.

A microcomputer chip having a ROM, a RAM, and a CPU is used for a part of the valve control device 29 and the concentration calculation display section 30.
It is realized as a functional element that operates based on a program recorded in advance on a recording medium such as M. Also,
As the element having a display function in the concentration calculation display section 30, a liquid crystal display panel or the like attached to the surface of the automatic neutralization titration analyzer main body (not shown) is used.

<Operation> When the developer 11 and the ultrapure water 12 are mixed, a second titration process is performed in advance, and then a first titration process is performed. Hereinafter, the procedure will be described.

First, in the second titration treatment, NaOH
An appropriate amount of the NaOH solution 16a in the container 16 is introduced into the measuring tube 23 through the second introducing tube 22, and then the pH electrode 2
The titration of the sulfuric acid reagent 15 a in the sulfuric acid tank 15 with the burette 25 is performed until the equivalence point is detected by 7. The sulfuric acid reagent 15a used here has a concentration of 0.1 to 1.0N.
Is a general one. Further, the NaOH container 16 is always provided as a new package each time measurement is performed, and is provided after being newly sealed in order to avoid a change in NaOH concentration over time.

When the equivalent point is reached, the valve controller 29 automatically closes the valve 28 of the burette 25. At this time, the drop amount of the sulfuric acid reagent 15a (the decrease amount of the sulfuric acid reagent 15a in the burette 25) and the titration cell 2
By comparing with the amount of the NaOH solution 16a in 6, the concentration calculation display section 30 accurately detects and displays the concentration of the sulfuric acid reagent 15a. The arithmetic expression at this time is as in the following expression (1).

Sulfuric acid concentration = (Specified concentration of NaOH × NaOH introduction amount) / Sulfuric acid consumption amount (1) In this manner, the sulfuric acid reagent 15 a in the sulfuric acid tank 15.
After the concentration of is determined (measured) with high accuracy, the solution in the titration cell 26 is discarded.

Next, in the first titration treatment, an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) is introduced into the dilution tank 13 as the developer 11 and the ultrapure water 12 is introduced into the dilution tank 13. In addition, the developer 11 is diluted.

At this time, the diluted developer 13 a in the dilution tank 13 is introduced into the titration cell 26 through the first introduction pipe 21, and then the aforementioned sulfuric acid reagent 15 a is dropped into the titration cell 26 through the burette 25. This operation is continued until the equivalence point is detected by the pH electrode 27, and when the equivalence point is reached, the valve control device 29 sets the valve 2 of the burette 25.
8 is closed. Then, based on the decrease amount of the buret 25 at this time, the diluted developer 1
The density of 3a is calculated. The operation formula at this time is as follows (2)
It is as the formula.

Developer concentration = (concentration of sulfuric acid reagent × amount of sulfuric acid reagent dropped) / introduced amount of developer (2) In the formula (2), the concentration of the sulfuric acid reagent is determined by the second titration process to be (1) ) Use the sulfuric acid concentration calculated using the equation as it is.

Thereafter, based on the calculated density, the developing solution 11 or ultrapure water 1
2 is again charged into the dilution tank 13, and the concentration is measured again with the automatic neutralization titration analyzer 14 and the sulfuric acid reagent 15a. By repeating the processing of such a procedure several times, the concentration measurement of the diluted developer 13a is adjusted to the required accuracy. Finally, the adjusted diluted developer 13a is transferred to the supply tank 17, and the process of diluting the developer is completed.

In parallel with the above processing, a resist film is applied to the upper surface of the substrate, masked thereabove, and then irradiated with ultraviolet rays to partially remove the resist film, as in the case described in the conventional example. Change the structure. And it is solubilized by the diluted developer 13a diluted as described above,
What is necessary is just to perform the pattern formation process which performed the predetermined wiring design (refer FIG. 6 and FIG. 7).

Here, FIG. 3 is a diagram showing the measurement results in this solution diluting apparatus, in which white circles show the case where calibration was not performed with sulfuric acid (conventional method), and black circles show the results of this embodiment. As shown in FIG. As is apparent from this figure, according to the solution diluting apparatus of this embodiment, there is almost no variation in the measurement results as compared with the prior art, and it can be seen that the measurement accuracy is dramatically improved. Thus, the sulfuric acid reagent 1 for titration
Since the concentration of the developer 5a is measured with high accuracy and the concentration of the diluted developer 13a is measured according to the measurement result, the developer concentration can be measured with extremely high accuracy. Can be

Embodiment 2 FIG. 4 shows a solution diluting apparatus according to Embodiment 2 of the present invention. In FIG. 4, elements having the same functions as those in the first embodiment are denoted by the same reference numerals. In the first embodiment, a general sulfuric acid reagent 15a having a concentration of 0.1 to 1.0 N is used. However, in order to enhance the titration accuracy with respect to the diluted developer 13a, a dilute sulfuric acid reagent is used. It is preferable to use. However, the longer the sulfuric acid reagent 15a in the sulfuric acid tank 15 is used as it is, the longer it takes to reach the equivalent point.

Therefore, in this embodiment, the density is set to 0.
A dilute sulfuric acid reagent 15a of less than 1N is used at least in the final stage of the titration, that is, in the latter half of the titration, and in addition, a general sulfuric acid reagent 18 having a concentration of 0.1 to 1.0N is added.
a was used in the initial stage of titration. That is, the solution diluting apparatus according to the present embodiment uses the dilute sulfuric acid reagent 15a having a concentration of less than 0.1 N in the solution diluting apparatus having the configuration described in the first embodiment, and the configuration described in the first embodiment. 4, a sulfuric acid tank 18 containing a sulfuric acid reagent 18a having a normal concentration is further provided as shown in FIG. Here, the sulfuric acid reagent 15a is supplied to the automatic neutralization titration analyzer 14 by a burette separately provided from the burette of the general sulfuric acid reagent 18a.
It is dripped in. Other configurations, for example, dilution tank 13
Is that the weight of the dilution tank 13 can be measured by a weighing scale 19, that the dilution tank 13 is made of a lightweight material, and that the NaOH container 16 is packaged in a disposable form.
All are the same as in the first embodiment.

In this embodiment, since two kinds of concentrations of the sulfuric acid reagents 18a and 15a are used, a first titration process in which the diluted developing solution 13a is titrated with the diluted sulfuric acid reagent 15a, and a dilution with the NaOH solution 16a In addition to the second titration process of mixing the sulfuric acid reagent 15a, a third titration process of mixing the NaOH solution 16a and the sulfuric acid reagent 18a is required.

That is, before or after the second titration process, as a third titration process, an appropriate amount of the NaOH solution 16a in the disposable packaged NaOH container 16 is automatically neutralized by the titration analyzer 14 Introduced to
Next, the sulfuric acid reagent 18a in the sulfuric acid tank 18 is titrated with a buret (not shown) until an equivalent point is detected by a pH electrode or the like. The sulfuric acid reagent 18a used here is a general one having a concentration of 0.1N or more and 1.0N or less.

When the equivalence point is reached, the automatic neutralization titration analyzer 14 accurately detects and displays the concentration of the diluted sulfuric acid reagent 15a in the same procedure as in the first embodiment.

After the concentration of the sulfuric acid reagent 18a in the sulfuric acid tank 18 is titrated (measured) with high precision in this way, the solution in the automatic neutralization titration analyzer 14 is discarded.

Before and after the third titration process,
The second titration treatment using the diluted sulfuric acid reagent 15a having a concentration of less than 0.1N has also been completed.

Next, in the first titration process, an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) is introduced into the dilution tank 13 as a developer 11 while measuring the weight of the dilution tank 13 with a weighing machine 19. At the same time, ultrapure water 12 is added into the dilution tank 13 to dilute the developer 11.

At this time, the diluted developer 13a in the dilution tank 13 is introduced into the automatic neutralization titration analyzer 14 through the first introduction pipe 21, and then the sulfuric acid reagent 18a described above is automatically supplied by a fixed amount through a burette or the like. Japanese titration analyzer 14
Drop into. After the dropping of the sulfuric acid reagent 18a with coarse accuracy until the approximate equivalent point is completed, the diluted sulfuric acid reagent 15a in the diluted sulfuric acid tank 15 is further dropped into the automatic neutralization titrator 14 through a burette or the like. The operation of dropping the diluted sulfuric acid reagent 15a is continued until an equivalent point is detected by a pH electrode or the like.

When the equivalent point is reached, the sulfuric acid reagent 1
The concentration of the diluted developer 13a is calculated based on the amount of each drop of the diluted sulfuric acid tank 8a and the diluted sulfuric acid tank 15 and the respective concentrations determined in the second and third titration processes.

Thereafter, based on the calculated density, the developer 11 or the ultrapure water 1
2 is again charged into the dilution tank 13, and the concentration is measured again in the automatic neutralization titration analyzer 14 using the diluted sulfuric acid reagent 15a. By repeating the processing of such a procedure several times, the concentration measurement of the diluted developer 13a is adjusted to the required accuracy. Finally, the adjusted diluted developer 13a is transferred to the supply tank 17, and the process of diluting the developer is completed.

According to this embodiment, in the initial stage of the introduction of the sulfuric acid reagent, the sulfuric acid reagent 18a having a normal concentration in the sulfuric acid tank 18 is introduced to prevent an increase in the time required for the introduction, and to accurately titrate in the latter half. When performing the above, by gradually adding the dilute sulfuric acid reagent 15a in the dilute sulfuric acid tank 15, accurate titration can be performed. Therefore, the measurement accuracy can be improved without increasing the time required for titration as compared with the case where only one type of sulfuric acid reagent is used (for example, Embodiment 1).

Third Embodiment FIG. 5 is a view showing a solution diluting apparatus according to a third embodiment of the present invention. In FIG. 5, the same reference numerals are given to elements having the same functions as in the first embodiment.

In the first embodiment, the concentration of the sulfuric acid reagent 15a in the sulfuric acid tank 15 is measured by performing the periodic titration of the sulfuric acid reagent 15a on the NaOH solution 16a by the automatic neutralization titration analyzer 14. However, in the solution diluting apparatus of this embodiment, a part of the sulfuric acid reagent 15a in the sulfuric acid tank 15 is sampled and transferred to a hydrometer (densitometer) 31, as shown in FIG. Is measured to measure the concentration of the sulfuric acid reagent 15a in the sulfuric acid tank 15.

Then, the concentration of the sulfuric acid reagent 15a measured by the hydrometer 31 is numerically input to the automatic neutralization titration analyzer 14 by an input device (not shown) such as a keyboard panel, and is based on the numerical value input here. To calculate the concentration of the diluted developer 13a.

With this configuration, the sulfuric acid reagent 15 is added to the diluted developer 13a by the automatic neutralization titration analyzer 14.
The concentration of the sulfuric acid reagent 15a can be measured at any time during the titration with a. Therefore, the concentration measurement accuracy of the diluted developer 13a in the automatic neutralization titration analyzer 14 can always be maintained at a high level.

In this embodiment, an input device such as a keyboard panel is used as a means for transmitting the measurement result of the hydrometer 31 to the automatic neutralization titration analyzer 14. However, instead of this, a specific gravity is used. It goes without saying that the result of the concentration measurement by the total 31 may be directly input to the automatic neutralization titration analyzer 14 through the wiring cable.

Embodiment 4 In each of the embodiments described above, an example was described in which the concentration accuracy was improved in the step of diluting the developing solution. However, the present invention is not limited to the diluting developing solution. The present invention can also be applied to a case in which another acid or alkaline reagent is diluted and produced.

For example, when diluting an aqueous ammonia solution or the like used in a cleaning step or the like in a device manufacturing process, titration with sulfuric acid, hydrochloric acid, or another acidic reagent is performed to make the concentration appropriate. In this case, in order to measure the concentration change of these acidic reagents with high accuracy, Na
Titrate with OH, KOH or other alkaline reagents. For example, the point that the weight of the dilution tank 13 can be measured by the weighing scale 19, the point that the dilution tank 13 is made of a lightweight material, the point that the container 16 is packaged in a disposable shape, and the like are all This is the same as in the first embodiment.

In this case, the concentration of the objective diluting solution can be measured with high accuracy using a solution diluting apparatus having the same configuration as that shown in FIG. 1 (Embodiment 1).

That is, first, in the second titration process,
An appropriate amount of an alkaline reagent (NaOH, KOH, etc.) 16a in a disposable packaged container 16 is introduced into the automatic neutralization titration analyzer 14, and then the sulfuric acid in the tank 15 is detected until an equivalent point is detected by a pH electrode. , Hydrochloric acid or another acidic reagent 15a is titrated with a burette or the like. Then, when the equivalent point is reached, the automatic neutralization titration analyzer 14 accurately detects and displays the concentration of the acidic reagent 15a in the same procedure as in the first embodiment. After titrating (measuring) the concentration of the acidic reagent 15a in the tank 15 with high accuracy in this manner,
The solution in the automatic neutralization titration analyzer 14 is discarded.

Next, in the first titration treatment, an alkaline aqueous solution (hereinafter referred to as “solution”) 11 such as an aqueous ammonia solution, which is an object of dilution production, is diluted with ultrapure water 12 in a dilution tank 13, Dilution solution 13a in dilution tank 13
Is introduced into the automatic neutralization titration analyzer 14, and then the sulfuric acid reagent 15a described above is dropped into the automatic neutralization titration analyzer 14 by a predetermined amount through a burette or the like. This acidic reagent 15
The dropping operation of a is continued until the equivalence point is detected with a pH electrode or the like. When the equivalence point is reached, the respective drop amounts of the sulfuric acid reagent 15a and the tank 15 and the respective amounts determined in the second and third titration treatments The concentration of the diluting solution 13a is calculated based on the concentration.

Then, based on the calculated concentration, the solution 11 or the ultrapure water 12 is used to satisfy the target concentration measurement accuracy.
Is again charged into the dilution tank 13, and the concentration is measured again in the automatic neutralization titration analyzer 14 using the acidic reagent 15a. By repeating such a procedure several times,
The concentration measurement of the dilution solution 13a is adjusted to the required accuracy. Finally, the adjusted diluted solution 13a is transferred to the supply tank 17, and the solution diluting process is completed.

Fifth Embodiment In a fifth embodiment of the present invention, the concentration of the sulfuric acid reagent for titration is adjusted while using the same basic structure as the conventional solution diluting apparatus shown in FIG. By performing the measurement periodically, the titration accuracy of the diluted developer is improved.

Since the general dilution tank 3 is of a large capacity and airtight, the diluted developer 1 whose concentration has been adjusted and diluted in the dilution tank 3 is less than the sulfuric acid reagent 5. Also, the change in concentration is extremely slow. In addition, although the concentration of the sulfuric acid reagent 5 changes with the lapse of time, there is almost no difference between the concentration and the specified value in the initial introduction stage.

Focusing on this situation, initially, the concentration of the diluted developer 1 is titrated with the sulfuric acid reagent 5 with high accuracy, and then the concentration of the sulfuric acid reagent 5 that changes with time is measured first. It can be seen that the detection can be performed using the diluted developer 1 itself. That is, just before transferring the diluted developer 1 whose concentration has been adjusted with high accuracy by titration with the sulfuric acid reagent 5 to the supply tank 6 as a result, a certain amount is introduced into the automatic neutralization titration analyzer 4,
The sulfuric acid reagent 5 is dropped into the diluted developer 1 and the amount of the sulfuric acid reagent 5 introduced until neutralization is reached is measured. Thus, the concentration of the sulfuric acid reagent 5 that has changed with the passage of time can be measured with high accuracy.

After the diluted developer 1 in the dilution tank 3 is transferred to the supply tank 6, when the developer 1 is newly diluted in the dilution tank 3, the concentration is measured with high precision as described above. The dilution process of the developing solution 1 may be performed while adjusting the concentration with high precision using the sulfuric acid reagent 5.

By doing so, the dilution concentration of the developing solution 1 can be adjusted with high precision without changing the apparatus configuration at all.

[Modification] In Embodiments 1 and 2 described above, the NaOH solution 16a was used as the reagent for performing the concentration analysis of the sulfuric acid reagent, but another alkaline reagent such as KOH was used. Of course, it is good.

In the second embodiment, the sulfuric acid tank 18 is newly added in addition to the structure of the first embodiment. For example, in the structure of the third embodiment, a dilute sulfuric acid reagent 15a is used. Then, a sulfuric acid tank 18 containing a general sulfuric acid reagent 18a having a concentration may be newly added thereto.

[0071]

According to the first aspect of the present invention, when the first solution is diluted by adding pure water, the second solution and the third solution are supplied to the neutralization titration analyzer. The concentration of the second solution is measured periodically or as needed by determining the equivalent point in mixing with the first solution, and based on the measurement result, the second solution is again used in the neutralization titration analyzer using the second solution. Since the solution is titrated, even if the concentration of the second solution changes with time, the changed concentration of the second solution can be accurately grasped, and thus the titration accuracy of the first solution is maintained at a high level. it can.

According to the second aspect of the present invention, the third
Is a replaceable container, a new third tank is introduced every time the concentration of the second container is measured.
The accuracy of the concentration measurement of the container can always be maintained at a high level.

According to the third aspect of the invention, the concentration of the second solution is measured by a hydrometer, and based on the measurement result,
Since the first solution is titrated using the second solution, even if the concentration of the second solution changes over time, the changed concentration of the second solution can be accurately grasped. The titration accuracy of the first solution can be maintained at a high level.

According to the fourth and fifth aspects of the present invention, when the first solution is titrated with the second solution, the fourth solution having a relatively high concentration is introduced in the initial stage. In addition, it is possible to prevent an increase in the time required for introduction, and to perform accurate titration by gradually adding the second solution having a relatively low concentration when performing accurate titration in the second half. Become. Therefore, the measurement accuracy can be improved without increasing the time required for titration, as compared with the case where titration is performed using only one type of solution.

According to the sixth aspect of the present invention, when diluting the first solution while measuring the weight of the first tank with a weighing scale, a lightweight material is used as the first tank. We can measure weight accurately. Therefore, before performing the titration with the second solution, the concentration of the first solution can be approximated to a desired concentration value to some extent, so that the titration process using the second solution can be completed in a short time. That is the concentration.

According to the seventh and eighth aspects of the present invention, since the concentration of the developing solution used in the resist process in the manufacturing process of the semiconductor device needs to be adjusted with high accuracy, the above-mentioned developing solution is used. When this developer is applied as the solution (1), the utility in the field of manufacturing semiconductor devices becomes extremely high.

According to the ninth to eleventh aspects of the present invention, with respect to the second solution (acidic reagent) having a concentration change with time, the first solution (development) in the initial state before the concentration change occurs. Liquid), the first solution is diluted to a desired concentration while repeatedly titrating, and a part of the first solution and a part of the second solution (acidic reagent) adjusted to the desired concentration are mixed here. And neutralized, and the change in the concentration of the second solution is measured from the amounts of the two solutions introduced at that time, so that the concentration of the second solution that has changed over time is increased. It can be measured with high accuracy. And again the first
The use of the second solution measured with high accuracy as described above when titrating the reagent (1) has an effect that the first titration accuracy can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a principle diagram showing an entire solution diluting apparatus according to a first embodiment of the present invention.

FIG. 2 is a principle diagram showing details of an automatic neutralization titration analyzer in the solution dilution device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a measurement result in the solution diluting apparatus according to the first embodiment of the present invention.

FIG. 4 is a principle view showing an entire solution diluting apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a principle view showing an entire solution diluting apparatus according to Embodiment 3 of the present invention.

FIG. 6 is a view showing a general resist process.

FIG. 7 is a view showing a general resist process.

FIG. 8 is a principle view showing the whole of a conventional solution diluting apparatus.

[Explanation of symbols]

1 developer, 2 ultrapure water, 3 dilution tank, 4 automatic neutralization titration analyzer, 5 sulfuric acid reagent, 6 supply tank, 11
Developer, 12 ultrapure water, 13 dilution tank, 13a dilution developer, 14 automatic neutralization titration analyzer, 15 sulfuric acid tank, 15a sulfuric acid reagent, 16 NaOH container, 16a
NaOH solution, 17 supply tank, 18 sulfuric acid tank,
18a sulfuric acid reagent, 19 weighing scale, 21 first inlet tube, 22 second inlet tube, 23 measuring tube, 24 third inlet tube, 25 burette, 26 titration cell, 27 p
H electrode, 28 valves, 29 valve control unit, 30 concentration calculation display unit, 31 hydrometer.

Claims (11)

[Claims] 1. A first tank for adding pure water to a predetermined first solution to dilute the first solution, and a second solution for titrating the diluted first solution comprises: A second tank to be stored in advance, and a third tank to store in advance a third solution for measuring the concentration of the second solution by determining an equivalent point in mixing with the second solution. And measuring the concentration of the second solution by obtaining an equivalent point in the mixing of the second solution and the third solution, and based on the measured concentration of the second solution, A neutralization titration analyzer for titrating the first solution diluted with the second solution. 2. The replaceable container according to claim 1, wherein the third tank is disposed and replaced together with the third solution every time the concentration of the second solution is measured. A solution diluting device, characterized in that: 3. A first tank for adding pure water to a predetermined first solution to dilute the first solution, and a second solution for titrating the diluted first solution is provided. A second tank to be stored in advance, a hydrometer for measuring the concentration of the second solution, and a second solution based on the concentration of the second solution measured by the hydrometer. And a neutralization titration analyzer for titrating the diluted first solution. 4. The solution diluting device according to claim 1, wherein a fourth solution of the same material as the second solution and having a higher concentration than the second solution is used. The apparatus further comprises a fourth tank stored in advance, wherein the neutralization titration analyzer drops the fourth solution in an initial stage of the first solution titration operation, and performs the first solution titration operation. Wherein both of the second solution and the fourth solution can be selectively switched so as to drop the second solution in the latter half of the step. 5. The solution diluting apparatus according to claim 4, wherein the second solution is a sulfuric acid reagent having a concentration of less than 0.1N, and the fourth solution is having a concentration of 0.1N or more. And a sulfuric acid reagent of 1.0N or less. 6. The solution diluting device according to claim 1, wherein the solution diluting device further includes a weighing scale for measuring a weight of the first tank. The liquid diluting apparatus is characterized in that a lighter material having a specific gravity as light as possible is used for the diluted first solution contained in the tank. 7. The solution diluting device according to claim 1, wherein the first solution is a developer used in a resist process in a semiconductor device manufacturing process. The solution diluting apparatus, wherein the second solution is an acidic reagent having a higher hydrogen ion concentration than the neutralization point. 8. The solution diluting apparatus according to claim 1, wherein the first solution is a developing solution used in a resist process in a semiconductor device manufacturing process, and the second solution is The solution diluting apparatus, wherein the solution is an acidic reagent having a higher hydrogen ion concentration than the neutralization point, and the third solution is an alkaline reagent having a lower hydrogen ion concentration than the neutralization point. 9. A solution concentration adjusting method for adjusting the concentration of a diluted first solution while titrating it with a predetermined second solution that causes a change in concentration over time, wherein the initial concentration before the change in concentration is adjusted. A first step of diluting and adjusting the first solution to a desired concentration while repeatedly titrating the first solution using the second solution in a state, and the second step adjusted to the desired concentration. A second step of collecting and neutralizing a part of the first solution and a part of the second solution, respectively, and measuring a change in the concentration of the second solution from the introduction amounts of the two solutions at that time And a method for adjusting a solution concentration. 10. The solution concentration adjusting method according to claim 9, wherein the first solution is a developer used in a resist process in a semiconductor device manufacturing process, and the second solution is a medium. A method for adjusting the concentration of a solution, characterized in that the acidic reagent has a higher hydrogen ion concentration than the sum point. 11. A first pattern forming step of applying a resist on the upper surface of a predetermined substrate, a second pattern forming step of masking above the resist, and a partial structure of the resist by a predetermined process. Forming a third pattern and a fourth pattern forming step of solubilizing only the resist having a changed structure or only the resist having a unchanged structure with a predetermined alkaline developer. In the method, as a step before the fourth step, the method further comprises a solution concentration adjusting step of adjusting the concentration of the diluted developer by titrating with a predetermined acidic reagent causing a concentration change with time, In the concentration adjusting step, the first solution is repeatedly titrated using the second solution in an initial state before a concentration change occurs, while the first solution is being titrated. A first step of diluting and adjusting the solution to a desired concentration; and collecting and neutralizing a part of the first solution and a part of the second solution adjusted to the desired concentration, respectively. A second step of measuring a change in the concentration of the second solution from the amounts of introduction of the two solutions at that time.