JP2003315316A - Method for measuring hydrogen peroxide concentration in circulating slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring hydrogen peroxide concentration in a circulating slurry for accurately and economically measuring hydrogen peroxide concentration in a circulating slurry used for polishing to smoothen, for example, a metallic thin film formed on a semiconductor substrate, thereby keeping constant the hydrogen peroxide concentration in the circulating slurry and efficiently and stably providing a high quality semiconductor. <P>SOLUTION: The method for measuring hydrogen peroxide concentration in a circulating slurry includes steps of sealing a part of the circulating slurry so as to provide a measurement system independent from a circulating slurry system, and after allowing a slurry sealed in the measuring system to stand, measuring hydrogen peroxide concentration in the slurry using an ultrasonic concentration meter. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for measuring the concentration of hydrogen peroxide in a circulating slurry.

[0002]

2. Description of the Related Art Conventionally, a slurry containing a hydrogen peroxide solution has been used for polishing a metal thin film formed on a semiconductor substrate such as a silicon wafer when manufacturing a semiconductor. The metal thin film is for connecting and wiring elements, resistors and the like to form a desired circuit. These metal thin films are generally formed by a vacuum evaporation method (CVD) in which a raw material such as tungsten or copper is heated and evaporated in a vacuum container to form a thin film on a semiconductor substrate.
Method) or a physical vapor deposition method (PVD method) such as a sputtering method in which a metal substance is sputtered using argon ions or the like and deposited on a semiconductor substrate.

Since the surface of the metal thin film formed by the above method is not flat, the metal thin film is usually formed on a semiconductor substrate and then the surface of the metal thin film is polished with a slurry using silica powder or the like as an abrasive. Is being done.
Further, during the flattening treatment of the surface of the metal thin film, physical polishing with an abrasive is performed, and at the same time, the hydrogen peroxide solution is mixed into the slurry to oxidize and dissolve the metal with the hydrogen peroxide solution. , Efficient processing is being performed.

In recent years, miniaturization and high performance of semiconductor products have been remarkable, while semiconductor products have a very fine structure, so that the surface of a metal thin film to be flattened by the above polishing method is uniform. It is an important factor for maintaining the high performance of semiconductor products to secure the uniformity and the uniformity of the surface of the metal thin film among the mass-produced products. For this reason, it is desirable to maintain the concentration of the hydrogen peroxide solution in the slurry to be constant, as well as to make the polishing agent uniform in the slurry used for planarizing the metal thin film.

On the other hand, in the conventional slurry used in the polishing process for flattening the metal thin film formed on the semiconductor substrate, the slurry circulating in the polishing process system (hereinafter, circulating slurry). Hydrogen peroxide solution,
Addition is performed at any time by the following method. First, the concentration of hydrogen peroxide solution in the circulating slurry is measured, and then the amount of hydrogen peroxide solution lacking with respect to the desired concentration of hydrogen peroxide solution is calculated using the measured value. By adding appropriate hydrogen peroxide solution to the slurry, the shortage of hydrogen peroxide solution is compensated, and thereby the concentration of hydrogen peroxide solution in the circulating slurry used is kept constant. .

[0006]

However, according to the studies by the present inventors, the above-mentioned conventional methods have the following problems, and the hydrogen peroxide concentration in the circulating slurry is kept constant without changing. Is difficult to maintain
It has been found that further improvement is required in order to obtain a semiconductor product having excellent quality by performing the flattening treatment of the metal thin film formed on the semiconductor substrate more uniformly and with good reproducibility.
That is, in the conventional method, in the measurement of the concentration of hydrogen peroxide solution in the circulating slurry, the accuracy and precision cannot be said to be sufficient, and the measurement accuracy is inferior. There was a case where the hydrogen peroxide solution could not be added accurately because it could not be determined accurately. Further, the conventional method for measuring the concentration of hydrogen peroxide solution has problems in terms of maintenance and running costs, and there is a point to be improved from the economical point of view.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, for example, to remove excess particles in a circulating slurry used for polishing treatment for flattening a metal thin film formed on a semiconductor substrate. It is an object of the present invention to provide a method for measuring the concentration of hydrogen peroxide water in a circulating slurry, which is capable of economically measuring the concentration of hydrogen oxide water with excellent accuracy. Further, the object of the present invention is to
By using the excellent method of measuring hydrogen peroxide concentration as described above, it is possible to keep the concentration of hydrogen peroxide in the circulating slurry always constant, which enables efficient and stable high quality semiconductor products. To provide.

[0008]

The above object can be achieved by the present invention described below. That is, the present invention is a method for measuring the concentration of hydrogen peroxide in a circulating slurry for measuring the concentration of hydrogen peroxide in the circulating slurry, wherein a part of the circulating slurry is enclosed. Then, the measurement system which is separated from the system of the circulating slurry and is in an independent state is provided, and after the slurry enclosed in the measurement system is allowed to stand,
The method for measuring the concentration of hydrogen peroxide water in a circulating slurry is characterized in that the concentration of hydrogen peroxide water in the slurry is measured by an ultrasonic densitometer. A preferred embodiment of the present invention is obtained in the above by further providing a pressure gauge in the measurement system, and measuring the pressure of the enclosed slurry in parallel with the measurement of the hydrogen peroxide concentration by the pressure gauge. It is a method for measuring the concentration of hydrogen peroxide solution in a circulating slurry, which has a correction calculation mechanism for correcting and calculating the measurement value of the hydrogen peroxide solution concentration measured by an ultrasonic densitometer based on the pressure measurement value. Further, a preferred embodiment of the present invention is a method for measuring the concentration of hydrogen peroxide solution in a circulating slurry, wherein the above-mentioned slurry is a slurry used when polishing the surface of a metal film formed on a wafer substrate. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to preferred embodiments. As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that, for example, hydrogen peroxide in a circulating slurry used for polishing treatment for flattening the surface of a metal thin film on a semiconductor substrate. The amount of water is measured, and the shortage amount of hydrogen peroxide water is detected according to the measured value, and hydrogen peroxide water is added to the circulating slurry based on the detected value to compensate for the shortage and It has been found that the conventional configuration in which the amount of hydrogen peroxide solution is kept constant has the following problems, particularly when measuring the amount of hydrogen peroxide solution in the circulating slurry.
That is, the conventional management of hydrogen peroxide concentration (hereinafter referred to as perhydrogen concentration) by measuring the concentration of hydrogen peroxide in the slurry and detecting the insufficient amount of hydrogen peroxide according to the measured value. It was found that the mechanism has the following problems.

(A) Conventionally, as a method for measuring the concentration of hydrogen peroxide solution that has been used, there is JP-A 2000-117.
An automatic titrator using a redox titration method using a reagent such as potassium permanganate or sulfuric acid as described in Japanese Patent No. 635 is mainly used. However, in the case of such a method, there is a problem that the running cost increases due to the consumption of the reagent and the operation man-hour increases due to the regular replacement of the reagent, and the syringe and the syringe seal part used when collecting the measurement sample are Since the target is slurry, there is a problem that it is consumed so much that it must be replaced in a short period of time, which is an economic problem.

(B) On the other hand, an ultrasonic densitometer that can measure the concentration of hydrogen peroxide solution in the slurry almost without maintenance is used as an alternative to the above automatic titration apparatus by the redox titration method. Is becoming
In this case, when using in-line (where a measuring device is placed in the circulation system of the slurry to perform measurement while circulating), the flow rate, pressure, temperature, etc. of the circulating slurry that is the measurement sample are used. Are susceptible to the influence of, the measurement value varies, and the measurement accuracy is lacking.

In order to solve the above-mentioned problems, the present invention separates the perhydrogen concentration in the circulation slurry used in the polishing step from the circulation system of the slurry into an independent system, and measures the ultrasonic concentration in the system. By using a meter, it is possible to perform accurate and accurate measurement, and by using the obtained measured value of the concentration of hydrogen peroxide, it is possible to accurately and accurately detect the concentration of hydrogen peroxide solution that is lacking. It makes it possible to accurately add the desired amount of hydrogen peroxide solution into the circulating slurry. The various effects obtained when the method for measuring the concentration of superfluous water in the circulating slurry of the present invention is used will be described below.

(I) In the present invention, instead of using an automatic titrator which uses a redox titration method or the like, the perhydrogen concentration is not used.
Since the measurement is performed using the ultrasonic densitometer, it is possible to reduce the running cost and the maintenance man-hour as compared with the conventional measuring method.

(Ii) In the present invention, the measurement of the superfluous water concentration by an ultrasonic densitometer is performed by enclosing a part of the circulating slurry in a system independent of the circulation system of the slurry. It is possible to eliminate the factors such as fluctuations in flow rate and pressure that cause measurement errors, which occurred when measuring using a sonic densitometer, and as a result, it is possible to improve the accuracy of concentration measurement of hydrogen peroxide solution. .

(Iii) Furthermore, in a preferred embodiment of the present invention, the above-mentioned measuring system is provided with a pressure gauge for measuring the pressure of the circulating slurry, and the pressure gauge is used in parallel with the measurement of the concentration of superfluous water. By configuring to measure the pressure of the enclosed slurry, it is possible to effectively suppress the occurrence of variations in the measured value of the superfluid concentration due to pressure fluctuations that have a particularly large effect, and thereby to improve the measurement accuracy of the superfluid concentration. It is possible to further improve.

Hereinafter, the method for measuring the concentration of superfluous water in the circulating slurry of the present invention which achieves the above-mentioned excellent effects will be described in more detail. FIG. 1 is a schematic diagram for explaining an example of a measurement system used in the method for measuring the concentration of superfluous water of the present invention. 1 in the figure is a slurry supply line,
Reference numeral 4 is a valve, 5 is a pressure gauge, and 6 is an ultrasonic densitometer. In the example shown in FIG. 1, the pressure gauge 5 is arranged in the measurement system together with the ultrasonic densitometer 6, and the pressure measurement is performed concurrently with the measurement of the concentration of the hydrogen peroxide solution. There is.

In the present invention, unlike the prior art, the measurement of the perhydrogen concentration is not carried out in the system in which the slurry is circulated, but a part of the slurry is enclosed from the circulated slurry and this is used as a measurement sample. By doing so, the concentration of superfluous water is measured by an independent system separated from the slurry circulation system. Because of the above-described configuration, in the present invention, as shown in FIG. 1, valves 2 to 4 are arranged in a part of the slurry supply line 1.
Then, when the measurement of the perhydrogen concentration is not performed, the valves 2 and 3 are opened and the valve 4 is closed by using these valves, whereby the slurry is ultrasonically passed through the pressure gauge 5. It is introduced into the densitometer 6 and constantly circulated. Next, when the concentration of superfluous water is measured, the controller 22 automatically closes the valves 2 and 3 to circulate the pressure gauge 5 and the ultrasonic densitometer 6 which are measurement systems. Enclose part of the slurry. By opening the valve 4 in conjunction with the movement of closing the valves 2 and 3, the circulation of the slurry in the slurry supply line 1 is continued regardless of the measurement system such as the concentration of superfluid water. Is configured to. Therefore, the polishing process, as usual,
It will be continued.

In the present invention, the pressure and the concentration of the perhydrogen of the slurry enclosed in the pressure gauge 5 and the ultrasonic densitometer 6 as described above are measured after standing. In particular,
The controller 22 may be controlled to perform the measurement after the preset measurement standby time has elapsed and the measurement system is stabilized. In the example shown in FIG. 1, the pressure measurement value and the superficial water concentration measurement value obtained by the above measurement system are input to the controller 22, and the controller 22 uses these measurement values to perform an operation to correct the pressure. The measured measured value of the superfluous water concentration is recorded in the controller 22. In the present invention, as described above, the measurement system is allowed to stand and then the concentration of superhydrogen is measured, which causes a measurement error when the concentration of hydrogen peroxide solution is measured by an ultrasonic densitometer. And the effect of pressure can be eliminated. As a result, it becomes possible to measure the concentration of the hydrogen peroxide solution accurately and accurately in the state where there is no variation.

Further, in order to further improve the reliability of the measured value of the concentration of superfluous water, the following constitution is preferable. First, after the measured value of the superfluous concentration measured as described above is recorded in the controller 22, the valves 2 and 3 are opened again and the valve 4 is closed to circulate the slurry in the measurement system. . Then, again, after the above-mentioned encapsulation of the slurry, each measurement, the input of the measured pressure value and the measured value of the superfluous water concentration to the controller 22 and the calculation by the controller 22, the pressure-corrected measured perhydrogenated water concentration value is recorded in the controller 22. . Then, this series of density measurement operation is repeated several times, and when several density recorded values fall within the preset allowable error range, the average of these several density recorded values is taken, It is preferable to use such a value as the concentration measurement result at a certain perhydrogen concentration measurement time.

FIG. 2 is a schematic configuration of the above-described method for measuring the concentration of superfluous water in a circulating slurry of the present invention applied to a slurry supply system for polishing a surface of a metal film formed on a wafer substrate. The figure is shown. In order to perform stable wafer polishing with the polishing apparatus 26, it is necessary to make the superfluid concentration in the circulating slurry constant, but this is achieved by applying the above-described method for measuring the superfluous concentration of the present invention. It becomes possible to do. To describe with reference to FIG. 2, the slurry to be supplied to the polishing apparatus 26 is adjusted to have a predetermined perhydrogen concentration by a hydrogen peroxide water addition mechanism 29 (hereinafter, referred to as a perhydrogen addition mechanism), and a slurry tank 31. After being stored in, the slurry tank 31 is constantly circulated by the slurry supply line 1 via the slurry supply device 27 and used. The perhydrogen concentration in the slurry is kept constant as described below. Reference numeral 28 in the figure indicates a measurement system to which the above-described method for measuring the perhydrogen concentration of the present invention is applied.

Hereinafter, referring to FIG. 2, a measuring system 28 to which the method for measuring the concentration of superfluid water of the present invention is applied, and a superfluid water adding mechanism 29.
A method of keeping the perhydrogen concentration in the circulating slurry constant will be described with reference to. The desired predetermined superfluid concentration is adjusted by the following series of operations. First, when a certain amount of superfluous water concentration measurement time preset by the controller 22 arrives, the measurement system 28 measures the superfluous water concentration in the slurry, and the measurement result of the superfluous water concentration is recorded in the controller 22. When the concentration measurement result of the measurement system 28 is equal to or lower than the desired concentration, the excess amount of the excess water in the slurry tank 31 is insufficient in the slurry tank 31 in order to adjust the concentration of the excess water in the slurry to the desired concentration. Hydrogen peroxide solution is added.

The hydrogen peroxide solution is added by a valve.
Although it may be added directly to the slurry tank 31, it is more preferable to add it in the following manner. That is, a storage tank for hydrogen peroxide water is provided, the hydrogen peroxide solution is supplied by pressurizing the tank with a constant pressure, the supply flow rate is quantified by a flow meter, and this is integrated. If the method of adding the hydrogen peroxide solution while quantifying the added amount is used, the hydrogen peroxide solution can be added well. In particular, an impeller type flow meter is used, and further, a hydrogen peroxide water supply path is provided with a superhydrogen addition mechanism 29 and a slurry tank 31.
The addition flow rate can be changed according to the installation distance with the flow rate control orifice that can maintain the addition flow rate constant, and the pulse from the impeller flow meter can be integrated instantaneously to determine the total addition amount of hydrogen peroxide water. By using the method of supplying the hydrogen peroxide solution while performing the quantitative determination, it is possible to inexpensively add the hydrogen peroxide solution at a minute flow rate in a better condition.

After a series of measurement of the concentration of superfluid water and addition of hydrogen peroxide water, the above-mentioned operation of measuring the superfluid concentration by the measurement system 28 is performed again after a preset waiting time, and the addition of the superfluid water as described above. It is confirmed whether or not the perhydrogen concentration in the circulating slurry has reached the desired concentration by the addition by the mechanism 29.
If the desired concentration has been reached, the per-water addition mechanism 29 will be idle until the next over-hydrogen concentration measurement time, but if the desired concentration has not been reached, the addition operation is performed again. After that, the concentration measurement operation and the addition operation are repeated until it is confirmed that the desired concentration is reached.
The concentration of hydrogen peroxide solution in the circulating slurry is kept constant.

[0024]

The present invention will be described in more detail with reference to the preferred examples. (1) Effect of pressure on the measurement of the concentration of superfluid In the schematic diagram shown in FIG. 1, three types of known concentrations of 1, 2, and 3 wt% are contained in the piping of the measurement system from valve 2 to valve 3. Using a slurry containing hydrogen oxide water, these were sealed at each pressure shown in Table 1, and in that state, the concentration of hydrogen peroxide water in the slurry was measured by an ultrasonic densitometer 6, and at that time, The effect of pressure fluctuations on the measured values obtained in the above was investigated. Table 1 shows the obtained results. In Table 1, the hydrogen peroxide concentration in the slurry measured by the redox titration method is described.

[0025]

As shown in Table 1, from this result, it was confirmed that the measurement result of the superfluid concentration obtained by the ultrasonic densitometer 6 tends to be a high value in proportion to the pressure. Therefore, using the results of Table 1 above, the correction of the variation in the measured value of the superfluid concentration caused by the pressure fluctuation was examined. As a result, the proportional constant is set to -0.0006,
It has been found that by correcting the variation in the measured value of the concentration of superfluous water caused by the pressure fluctuation by the following formula, it is possible to perform highly accurate measurement with the ultrasonic densitometer. T in the formula is
It is the pressure at which each slurry for which the concentration of hydrogen peroxide was measured was enclosed.

[0027]

Using the above equation, a comparison was made between the case where pressure correction was performed at each pressure T and the case where no pressure correction was performed, and the pressure correction was applied to the actual measured value of the perhydrogen concentration measured by the ultrasonic densitometer. The effect of the case was confirmed. 3 to 5 are graphs showing the results. As a result, when the concentration of hydrogen peroxide solution was measured without pressure correction for a slurry containing hydrogen peroxide solution of known concentration, there was a large error from the true value in proportion to the increase in pressure. I was able to confirm. On the other hand, it has been found that by correcting the pressure fluctuations described above, it is possible to measure the concentration of the hydrogen peroxide solution with a small error from the true value. Therefore, if the pressure of the slurry is measured simultaneously with the measurement of the concentration of the hydrogen peroxide solution and the above-mentioned measurement value is corrected, the concentration of the hydrogen peroxide solution in the slurry can be ultrasonically measured without being affected by the pressure fluctuation. When measured by a densitometer, accurate and accurate measurement results can be obtained.

(2) The controller 22 is constructed by assembling the circuit schematically shown in FIG.
Specify the discharge amount of hydrogen peroxide water by the, and pressurize the stock solution overpressure from the storage tank of the stock solution overpressure using the nitrogen line connected to the tank, and actually discharge it with the graduated cylinder. The measured amount was measured. At this time, the pressure of the pressurizing nitrogen was made constant and varied, and a comparative experiment was conducted to determine the discharge amount of the undiluted solution per flow for the specified discharge amount. It was Table 2
The results are shown in FIG.

[0030]

As shown in Table 2, in the case where the pressure of nitrogen for pressurization at the time of discharging the pressurized hydrogen from the storage tank using a nitrogen line is constant, when the pressure fluctuates,
Obviously, it was confirmed that the discharge amount was smaller than the specified discharge amount and the error was large. Conversely, if a storage tank is used, it is possible to make the discharge pressure constant, and further, in this way, when adding the hydrogen peroxide solution to the slurry, the desired amount can be accurately adjusted. It was confirmed that they could be added well.

Example 1 A test plant as shown in FIG. 2 was prepared. Then, the slurry was circulated without adding hydrogen peroxide solution.
The slurry was prepared by adding a hydrogen peroxide solution having a known concentration of 1.73 wt% and 1.84 wt% to a silica slurry for polishing tungsten (Semi-Space W2000 manufactured by Cabot Microelectronics Corporation). It was used and the measurement of the perhydrogen concentration was carried out as follows. The measurement is performed by an ultrasonic densitometer (Ultrasonic liquid densitometer FUD-1 manufactured by Fuji Industry Co., Ltd.).
MODEL-11), and at the same time, the pressure of the slurry enclosed in the measurement system was measured by a pressure gauge (pressure sensor TPL-5A-N manufactured by Surpass Industry Co., Ltd.). Then, the variation in the measured value of the superfluid concentration caused by the pressure fluctuation was corrected by the above-described formula, and the obtained result was recorded in the controller 22.

As described above, the perhydrogen concentration is 1.73 w.
The known slurries of t% and 1.84 wt% were circulated, respectively, and the measurement by the ultrasonic densitometer was repeated three times. The results obtained are shown in Table 3. The average values were 1.73 wt% and 1.83 wt%, respectively, and the measurement results were close to the true values, confirming that accurate measurement was performed.
The standard deviations are 0.013 wt% and 0.
It was 006 wt%, and it was confirmed that there was little variation during repeated measurements and that accurate measurements were made.

[0034]

USE EXAMPLE 1 The slurry was circulated while adding hydrogen peroxide solution from the 2 L capacity storage tank constituting the perhydrogen addition mechanism 29 to the slurry tank 31. At this time, the slurry was supplied by the slurry supply device 27 so as to circulate at a rate of 3 L / min. Further, in this example of use, an impeller flow meter (Mini Wheel Flow Meter W812-1-T manufactured by Tokyo Keiso Co., Ltd.) was used to quantify the amount of hydrogen peroxide added to the slurry. Using. Further, a flow rate control orifice (φ1.5 mm) was used. A programmable controller FA-M3 manufactured by Yokogawa Electric Corp. was used as the controller.

With the above constitution, the slurry was circulated.
Further, the concentration of the desired hydrogen peroxide solution input to the controller was set to 2.00 wt%. Then, adjusting the perhydrogen concentration in the slurry tank to be lower than the desired concentration, and measuring the perhydrogen concentration and the series of operations of adding hydrogen peroxide water described above, Attempts to adjust to the desired concentration were made three times. The results are shown in Table 4.
As a result, as shown in Table 4, the desired concentration was 2.00 wt.
It was confirmed that the perhydrogen concentration can be accurately and accurately controlled within the range of ± 0.02 wt% with respect to%.

[0037]

[0038]

As described above, according to the present invention, for example, it is possible to improve the concentration of superfluous water in a circulating slurry used for polishing treatment for flattening a metal thin film formed on a semiconductor substrate. Provided is a method for measuring the concentration of superfluid water in a circulating slurry, which can be economically measured with high accuracy. Furthermore, according to the present invention, by using the above-mentioned excellent method for measuring the concentration of superfluous water, it becomes possible to always keep the concentration of superfluous water in the circulating slurry constant, resulting in high quality semiconductor products. It can enable efficient and stable provision.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a measurement system used in the method of the present invention.

FIG. 2 is a schematic configuration diagram when the method of the present invention is applied to a slurry supply system.

FIG. 3 is a diagram showing a result showing a difference between the actual measurement value of the concentration of superfluous water measured by an ultrasonic densitometer and the presence / absence of pressure correction.

FIG. 4 is a diagram showing a result showing a difference between the presence or absence of pressure correction with respect to an actual measurement value of the concentration of superfluous water measured by an ultrasonic densitometer.

FIG. 5 is a diagram showing results showing a difference between the actual measurement value of the superfluous water concentration measured by the ultrasonic densitometer and the presence / absence of pressure correction.

FIG. 6 is a graph showing the results of the difference in the amount of addition of the presence or absence of pressure fluctuation during the addition of hydrogen peroxide solution.

[Explanation of symbols]

1: Slurry supply line 2, 3, 4: Valve 5: Pressure gauge 6: Ultrasonic densitometer 19: Valve 21: Level meter 22: Controller (PLC) 26: Polishing device 27: Slurry supply device 28: Measurement system 29: Overwater addition mechanism 31: Slurry tank

Claims (3)

[Claims] 1. A method for measuring the concentration of hydrogen peroxide solution in a circulating slurry for measuring the concentration of hydrogen peroxide solution in a circulating slurry, comprising enclosing a part of the circulating slurry. A measurement system that is separated from the system of the circulating slurry and is set in an independent state is provided, and the slurry enclosed in the measurement system is allowed to stand still, and then the concentration of hydrogen peroxide solution in the slurry is measured by ultrasonic waves. A method for measuring the concentration of hydrogen peroxide water in a circulating slurry, which is characterized in that it is carried out by a densitometer. 2. A pressure gauge is further provided in the measurement system,
The pressure of the enclosed slurry is measured in parallel with the measurement of the hydrogen peroxide concentration by the pressure gauge, and the measured value of the hydrogen peroxide concentration measured by the ultrasonic concentration meter is corrected by the obtained pressure measurement value. The method for measuring the concentration of hydrogen peroxide solution in the circulating slurry according to claim 1, further comprising a correction calculation mechanism that 3. The method for measuring the concentration of hydrogen peroxide water in a circulating slurry according to claim 1, wherein the slurry is a slurry used when polishing the surface of a metal film formed on a wafer substrate.