Method for purifying benzotriazole and / or derivatives thereof

Abstract

The invention belongs to the technical field of semiconductors and electronic chemicals, and particularly discloses a method for purifying benzotriazole and / or derivatives thereof, which comprises the following steps: S1, adding a solvent into benzotriazole and / or derivatives thereof, mixing, and adding acid to adjust the pH value to be below 5; s2, alkali is added to adjust the pH to be 11 or above, cooling and standing are carried out, a filter cake obtained through filtering is washed and dried, and a purified product is obtained. According to the purification method provided by the invention, the content of the metal ions can be rapidly and effectively reduced to be less than 100ppb, the process method is simple and easy to operate, the purification cost can be well controlled, and the purification method has a good application prospect in the microelectronic fields such as semiconductor wafer cleaning and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors and electronic chemicals, and in particular relates to a method for purifying benzotriazole and / or its derivatives. Background Art

[0002] Benzotriazole (BTA) and its derivatives are effective corrosion inhibitors for copper and its alloys and are common raw materials in the preparation of cleaning and polishing fluids.

[0003] Formulated electronic chemicals such as etching solutions, cleaning solutions, and polishing solutions require high-purity electronic-grade raw materials for production, and have very high requirements for the purity, metal ion content, and impurity control of electronic-grade raw materials. The production of electronic-grade raw materials has high requirements for its production process, equipment, and environment. Due to the late start of the domestic semiconductor industry, the relevant electronic-grade raw material market is not mature enough. At present, most of them use industrial-grade raw material products and purify the raw materials through post-processing to produce electronic-grade raw materials. Summary of the invention

[0004] The present invention provides a method for purifying benzotriazole and / or its derivatives, which can reduce the content of metal ions therein to below 100 ppb, so that the benzotriazole and / or its derivatives can be used in the semiconductor industry.

[0005] The technical solution of the present invention is to provide a method for purifying benzotriazole and / or its derivatives, comprising the following steps: S1, mixing benzotriazole and / or its derivatives with a solvent, adding acid and adjusting the pH to below 5; S2. Add alkali to the liquid obtained in S1 to adjust the pH to above 11, cool and let stand, and wash and dry the filter cake obtained by filtration to obtain the purified product.

[0006] Furthermore, the solvent is a mixture of water and one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0007] Furthermore, the solvent is a mixture of water, N,N-dimethylacetamide and dimethyl sulfoxide in a volume ratio of 1-3:4-7:2-3.

[0008] Furthermore, the acid is a mixture of one or more of sulfuric acid, phosphoric acid, acetic acid, citric acid or succinic acid.

[0009] Furthermore, acid is added to S1 to adjust the pH to 3-5.

[0010] Furthermore, the solvent addition and the acid addition in S1 are mixed under heating regulation, and the heating temperature is 50-80°C.

[0011] Furthermore, the base in S2 is tetramethylammonium hydroxide and / or ammonia water; the base is added to adjust the pH to 11-12.

[0012] Furthermore, one or more solvents are used for washing and filtering, and drying is vacuum drying. Furthermore, steps S1-S2 are repeated multiple times to obtain a purified product.

[0013] Furthermore, derivatives of benzotriazole include but are not limited to toluene benzotriazole or 1-hydroxybenzotriazole.

[0014] The present invention has the following beneficial effects: Benzotriazole and / or its derivatives are organic heterocyclic compounds. Generally speaking, benzotriazole and / or its derivatives are more soluble in organic polar solvents but difficult to dissolve in non-polar solvents, slightly soluble in ethanol and ether, and easily soluble in lower fatty alcohols, acetone, cyclohexane, benzene, toluene, chloroform and dimethylformamide, etc. The present invention adopts a combination of strong polar solvents to improve the solubility of benzotriazole and / or its derivatives, thereby improving the purification yield. The selected organic solvents are all commonly used components in the production of cleaning agents, and these solvents can find electronic grade raw materials with good quality on the market, will not introduce new metal ion impurities, and these organic solvents are very easy to remove and will not remain in the desired target product.

[0015] After the dissolution, the pH of the present invention is adjusted to be acidic. Under acidic conditions, benzotriazole and / or its derivatives can fully dissociate from metal ions, and the H + Replacing the positively charged metal ions makes it easier to remove the metal ions in the subsequent process, which can improve the removal efficiency of the metal ions. In the subsequent impurity removal process, the acidity of the system is suddenly changed to alkalinity, which can make the free metal ions easier to precipitate.

[0016] The purification method provided by the present invention can quickly and effectively reduce the impurity content, has a simple process method, is easy to operate, can well control the purification cost, and will have good application prospects in microelectronic fields such as semiconductor wafer cleaning. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0018] The raw materials purified in the following examples and comparative examples include benzotriazole (BTA), toluenetriazole (TTA) or 1-hydroxybenzotriazole (HOBT), and the metal ion concentrations (unit: ppb) in the raw materials were tested by ICP-MS. See Table 1 below for details.

[0019] Table 1

[0020] The water used in the following examples and comparative examples is ultrapure water, and the organic solvents, acids and bases are all electronic grade (metal ion content is less than 1 ppb).

[0021] Example 1 A method for purifying benzotriazole comprises the following steps: S1. Take 50 g of benzotriazole, add 500 g of a solvent consisting of ultrapure water, N,N-dimethylacetamide (DMAC) and dimethyl sulfoxide (DMSO) in a volume ratio of 2:5:3, heat to 50°C and mix well, and add acetic acid to adjust the pH to 4; S2. Add tetramethylammonium hydroxide (TMAH) to the solution to adjust the pH to 12, cool to below 10°C and let stand for 30 minutes; wash the filter cake obtained by vacuum filtration with ultrapure water three times, and vacuum dry to obtain purified benzotriazole, which is recorded as 1-1.

[0022] The same method was used to purify TTA and HOBT to obtain purified TTA and HOBT, which were denoted as 1-2 and 1-3, respectively.

[0023] The products obtained from 1-1, 1-2 and 1-3 were tested by ICP-MS, and the contents of various metal ions are shown in Table 2, unit: ppb.

[0024] Table 2

[0025] Example 2 The scheme is the same as Example 1-1, the only difference is the solvent. Specifically, 2-1 is a mixture of ultrapure water, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) in a volume ratio of 2:5:3; 2-2 is a mixture of ultrapure water, N,N-dimethylacetamide (DMAC), and N-methylpyrrolidone (NMP) in a volume ratio of 2:5:3; 2-3 is a mixture of ultrapure water, N-methylpyrrolidone (NMP) and sulfone (Sulfone) in a mass ratio of 2:5:3; 2-4 is a mixture of ultrapure water, dimethyl sulfoxide (DMSO) and monoethanolamine (MEA) in a volume ratio of 2:5:3; 2-5 is a mixture of ultrapure water, N,N-dimethylacetamide (DMAC) and monoethanolamine (MEA) in a volume ratio of 2:5:3; 2-6 is a mixture of ultrapure water, N,N-dimethylacetamide (DMAC) and isopropyl alcohol (IPA) in a volume ratio of 2:5:3; 2-7 All solvents are ultrapure water and sulfone in a volume weight ratio of 8:2.

[0026] The purified benzotriazole obtained in the above example was tested by ICP-MS, and the contents of various metal ions are shown in Table 3, unit: ppb.

[0027] Table 3

[0028] From the removal effects of Examples 2-1 to 2-7, it can be seen that the stronger the polarity of the solvent, the better the removal effect on metal ions in benzotriazole.

[0029] Example 3 The scheme is the same as Example 1-1, the only difference is the number of times of impurity removal. Specifically, for the sample obtained in Example 1-1, the purification is repeated 1 to 2 times. 3-2 is purified once on the basis of 1-1, and 3-3 is purified twice on the basis of 1-1. The purified benzotriazole obtained in the above example was tested by ICP MS, and the content of each metal ion is shown in Table 4, unit: ppb.

[0030] Table 4

[0031] The above examples illustrate that the method has a good effect on removing metal ions from benzotriazole, and can significantly reduce the metal ion content in benzotriazole by increasing the purification times, so that it can be applied to the semiconductor integrated circuit manufacturing industry.

[0032] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for purifying benzotriazole and / or its derivatives, characterized in that: The following steps are involved: S1. Mix benzotriazole and / or its derivatives with a solvent, fully dissolve and stir evenly, and add acid to adjust the pH to below 5; S2. Add alkali to the liquid obtained in S1 to adjust the pH to above 11, cool and let stand, and wash and dry the filter cake obtained by filtration to obtain the purified product.

2. The purification method according to claim 1, characterized in that: The solvent is prepared by mixing water with one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

3. The purification method according to claim 2, characterized in that: The solvent is a mixture of water, N,N-dimethylacetamide and dimethyl sulfoxide in a volume ratio of 1-3:4-7:2-3.

4. The purification method according to claim 1, characterized in that: The acid is a mixture of one or more of sulfuric acid, phosphoric acid, acetic acid, citric acid or succinic acid.

5. The purification method according to claim 1, characterized in that: Add acid to S1 to adjust the pH to 3-5.

6. The purification method according to claim 1, characterized in that: In S1, the solvent addition and the acid addition are mixed under heating conditions, and the heating temperature is 50-80°C.

7. The purification method according to claim 1, characterized in that: The alkali in S2 is tetramethylammonium hydroxide and / or ammonia water; the alkali is added to adjust the pH to 11-12.

8. The purification method according to claim 7, characterized in that: During washing and filtering, one or more solvents are used for washing, and drying is vacuum drying.

9. The purification method according to any one of claims 1 to 8, characterized in that: Steps S1-S2 are repeated multiple times to obtain a purified product.

10. The purification method according to claim 9, characterized in that: Derivatives of benzotriazole include, but are not limited to, toluenetriazole or 1-hydroxybenzotriazole.

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