JPH0912306A - Method for refining aqueous hydrogen peroxide - Google Patents

Abstract

PURPOSE: To provide aq. hydrogen peroxide having high purity which has extremely low concn. of a metal content as an impurity, and thereby, which is suitable to be used for the production process of semiconductors. CONSTITUTION: In this method, aq. crude hydrogen peroxide containing metal contents as an impurity is subjected to contact treatment with a strong-acidic cation exchange resin to obtain the objective high-purity aq. hydrogen peroxide. In this method, the strong-acidic cation exchange resin pre-treated by being made in contact with the aq. hydrogen peroxide having <=20wt.ppt cocn. of each metal component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying hydrogen peroxide water. More specifically, the present invention relates to a method for purifying hydrogen peroxide solution, which has a very low concentration of metal components as impurities and therefore can obtain highly pure hydrogen peroxide solution that can be optimally used in a semiconductor manufacturing process. It is a thing.

[0002]

2. Description of the Related Art Hydrogen peroxide is used as a component of a wafer cleaning liquid in a semiconductor manufacturing process.
The hydrogen peroxide solution used here is required to be highly clean and pure. In particular, the presence of metal components such as iron, aluminum, sodium, calcium and magnesium in the hydrogen peroxide solution significantly reduces the reliability of the obtained semiconductor. On the other hand, the required level for the reliability of semiconductors has become higher in recent years, and for that purpose, highly pure hydrogen peroxide solution in which the concentration of each metal component is controlled to a lower level is required.

By the way, as a method for purifying hydrogen peroxide solution, a method is known in which hydrogen peroxide solution is brought into contact with an ion exchange resin to adsorb and remove impurities. However, it has been difficult to say that the hydrogen peroxide solution obtained by the conventional method is necessarily satisfactory in light of the above-mentioned highly required levels.

[0004]

Under the present circumstances,
The problem to be solved by the present invention is that the concentration of the metal component as an impurity is extremely low, and therefore hydrogen peroxide solution of high purity can be obtained which can be optimally used in the semiconductor manufacturing process. The point is to provide a method.

[0005]

That is, according to the present invention, a crude hydrogen peroxide solution containing a metal component as an impurity is subjected to a contact treatment with a strongly acidic cation exchange resin to obtain a highly pure hydrogen peroxide. A method for purifying hydrogen peroxide water, which uses a strongly acidic cation exchange resin pretreated by contacting with hydrogen peroxide water having a metal component concentration of 20 wtppt or less. Is.

The details will be described below.

As the crude hydrogen peroxide solution to be purified in the present invention, hydrogen peroxide solution produced by the industrially produced anthraquinone method or the like can be used.
Further, hydrogen peroxide having high purity, which is so-called for electronic industry, may be used. For the concentration of hydrogen peroxide water,
Although not particularly limited, it is usually 1 to 65% by weight, preferably 1 to 40% by weight.

As the strongly acidic cation exchange resin used in the present invention, a styrene type strongly acidic type resin is usually used, and it is finally regenerated into an H type so that it can be used as an H type or Na type at the time of purchase. either will do.

The present invention is a method for purifying hydrogen peroxide water, which obtains high-purity hydrogen peroxide by subjecting crude hydrogen peroxide water containing metal components as impurities to contact treatment with a strongly acidic cation exchange resin. Although it belongs to the so-called adsorption method, the strongly acidic cation exchange resin used is pretreated by contacting it with hydrogen peroxide solution having a metal component concentration of 20 wt. It is necessary to use a cation exchange resin. By using the strongly acidic cation exchange resin which has been subjected to such characteristic pretreatment, it is possible to obtain highly pure hydrogen peroxide water having an extremely low content of metal components as impurities.

The hydrogen peroxide solution used in the pretreatment has a metal component concentration of 20 weight ppt or less contained therein. Examples of the metal component generally include iron, aluminum, sodium, calcium, magnesium and the like. As the hydrogen peroxide solution used here, for example, a crude hydrogen peroxide solution containing a metal component as an impurity is subjected to a contact treatment with an ion exchange resin to obtain high purity hydrogen peroxide. Ion exchange pretreated by contacting with a high-purity mineral acid aqueous solution having a metal component concentration of 20 wt ppt or less and further contacting with ultrapure water having a metal component concentration of 10 wt ppt or less A hydrogen peroxide solution obtained by highly adsorbing and removing metal components using a resin can be used. Further, high-purity hydrogen peroxide water obtained by the present invention may be used.

The contact between the strongly acidic ion exchange resin and the hydrogen peroxide solution in which the concentration of each metal component is 20 weight ppt or less at the time of pretreatment is carried out as follows. The contact may be performed by either a batch method or a column flow method, but the column flow method is preferable from the viewpoint of work efficiency. When the column flow method is adopted, the flow rate of the hydrogen peroxide solution used for the pretreatment is usually 0.1 to 50 hr ⁻¹ in space velocity (hereinafter referred to as “SV”), but more preferable. Is ¹ to 10 hr ⁻¹ . The amount of hydrogen peroxide solution used for the pretreatment is the liquid passage ratio (BV: Be
d Volume) is 5 times or more, preferably 10 times or more. The concentration of the hydrogen peroxide solution used for the pretreatment is usually 1 to 65% by weight, more preferably 10 to 65% by weight.
40% by weight. Further, the purity of the hydrogen peroxide water may be such that the concentration of each metal component is 20 weight ppt or less, but it is preferable that the amount of impurities is as small as possible. The contact temperature between the hydrogen peroxide solution and the strongly acidic cation exchange resin is not particularly limited, but it is preferably 30 ° C. or lower, more preferably 10 ° C. or lower in order to suppress decomposition of the cation exchange resin.

From the viewpoint of enhancing the metal removal efficiency, it is preferable to pass the crude hydrogen peroxide solution through a downward flow.

The contact treatment between the crude hydrogen peroxide solution containing a metal component as an impurity and the pretreated strong acid ion exchange resin is carried out as follows. The contact may be performed by either a batch method or a column flow method, but the column flow method is preferable from the viewpoint of work efficiency. The flow rate in the case of using the column flow method is usually 0.1 to 50 hr ^-1 , and more preferably ¹ to 10 hr ^-1 . The contact temperature is usually 30 ° C or lower, preferably 10 ° C or lower.

Next, an example of a specific method for carrying out the present invention will be described. First, the strongly acidic cation exchange resin is subjected to contact treatment with an aqueous solution of high-purity mineral acid such as hydrochloric acid, and then subjected to contact treatment with ultrapure water. Here, the aqueous solution of the mineral acid is preferably a high-purity mineral acid aqueous solution in which the concentration of each metal component is 20 weight ppt or less. Moreover, as the ultrapure water, ultrapure water having a metal component concentration of 10 wt. The contact may be performed by either a batch method or a column flow method, but the column flow method is preferable from the viewpoint of work efficiency. When the column flow method is adopted, the flow rate of high-purity mineral acid or ultrapure water is usually 0.1 to 50 hr ^-1 , and more preferably ¹ to 10 hr ^-1 . When the contact treatment with crude hydrogen peroxide solution described below is carried out in a descending flow of the column, each treatment using high-purity mineral acid is preferably started in a descending flow, and is finally carried out in an ascending flow in the final stage. The amount of high-purity mineral acid used for the treatment is preferably 50 times or more the amount of ion exchange resin,
More preferably, it is 100 times or more. The amount of ultrapure water used for the treatment is preferably 10 times or more, more preferably 50 times or more the amount of the ion exchange resin. After the above processing, the above-mentioned pretreatment of the present invention is performed, and further the contact treatment of the present invention is performed. Since the metal adsorbing ability of the resin decreases as the contact treatment progresses, the series of treatments described above may be repeated each time.

[0015]

The present invention will be described below with reference to examples and comparative examples. The metals were analyzed by the ICP-MS method and the flameless atomic absorption method.

Example 1 120 ml of IR120B (Na type, manufactured by Organo), which is a strongly acidic cation exchange resin, has an inner diameter of 40 mm and a length of 250.
mm column made of Teflon, first with ultra pure water SV =
It was washed with upflow for 10 hours at 10 hr ^-1 , and then a 6 wt% hydrochloric acid aqueous solution was passed for 20 hours with downflow SV = 5 hr ^-1 ,
Subsequently, the ascending flow SV = 5 hr ⁻¹ was passed for 10 hours. After substituting with ultrapure water, this column was thoroughly washed with ultrapure water in a descending flow in a clean room (class 1000), and then 10 weight parts of sodium, 10 weight parts of calcium, 3 weight parts of magnesium as impurities. ppt
31% by weight of high-purity hydrogen peroxide solution containing
= 5 hr ^-1 for 4 hours for pretreatment. Continuing, as the amount of impurities, sodium 2 wtpp
b, calcium 3 weight ppb and magnesium 6 weight p
Contact treatment was carried out by passing a crude hydrogen peroxide solution containing pb at a SV of 5 hr ⁻¹ in a downward flow. After the treatment, the concentration of each metal in the hydrogen peroxide water was not more than 2 weight ppt of sodium, 2 weight ppt of calcium and 1 weight ppt of magnesium.

Example 2 120 ml of strongly acidic cation exchange resin SKT10 (H type manufactured by Mitsubishi Chemical Co., Ltd.) has an inner diameter of 40 mm and a length of 250 mm.
Was first washed with ultrapure water at SV = 10 hr ⁻¹ for 1 hour, and then a 6 wt% hydrochloric acid aqueous solution was passed at SV = 5 hr ⁻¹ for 15 hours in an ascending flow, It was replaced with ultrapure water. This column is clean room (class 100
After thoroughly washing with ultrapure water in a downward flow in 0), 31% by weight of high-purity hydrogen peroxide solution containing 10 wt. Ppt of sodium, 10 wt. Ppt of calcium and 3 wt. Downflow SV = 5h
Pretreatment was carried out by passing the solution at r ⁻¹ for 20 hours. Subsequently, a raw material hydrogen peroxide solution containing 2 weight parts ppb of sodium, 3 weight parts ppb of calcium, and 6 weight parts ppb of magnesium as the amount of impurities was passed in a descending flow at SV = 5 hr ⁻¹ for contact treatment. The concentration of each metal in the hydrogen peroxide water after the treatment was 1.5 weight ppt of sodium, 1.5 weight ppt of calcium and 1 weight ppt of magnesium or less.

Comparative Example 1 Using the same method as in Example 1 except that the pretreatment of washing with high-purity hydrogen peroxide solution was not performed, sodium 2 weight ppb, calcium 3 weight ppb and magnesium 6 were used.
When the raw material hydrogen peroxide solution containing the weight ppb was purified,
Sodium 9.5 wtppt, calcium 10 wtpp
An aqueous hydrogen peroxide solution containing t and 3 ppt of magnesium was obtained.

[0019]

As described above, according to the present invention, the concentration of the metal component as an impurity is extremely low, and therefore, it is possible to obtain a highly pure hydrogen peroxide solution which can be optimally used in the semiconductor manufacturing process. It was possible to provide a method for purifying hydrogen water.

Claims (1)

[Claims] 1. A method for purifying hydrogen peroxide water, which comprises subjecting crude hydrogen peroxide water containing a metal component as an impurity to contact with a strongly acidic cation exchange resin to obtain high purity hydrogen peroxide, A method for purifying hydrogen peroxide solution using a strongly acidic cation exchange resin pretreated by contacting with hydrogen peroxide solution having a metal component concentration of 20 ppt or less.