Preparation method of hydroxylamine aqueous solution suitable for semiconductor field

Abstract

The invention discloses a preparation method of a hydroxylamine aqueous solution applicable to the field of semiconductors, which comprises the following steps: (1) adding an inorganic alkali aqueous solution into a hydroxylamine salt aqueous solution until the pH value of the hydroxylamine salt aqueous solution reaches 9-11 to obtain a hydroxylamine aqueous solution crude product; (2) adding an organic solvent into the hydroxylamine aqueous solution crude product, so that the solubility of a salt-containing component is changed, further crystallizing and separating out, and carrying out solid-liquid separation to remove a salt-containing solid, so as to obtain a desalted hydroxylamine solution; (3) carrying out reduced pressure distillation on the desalted hydroxylamine solution to remove the organic solvent, and increasing the concentration of hydroxylamine by azeotropy of the organic solvent and water to obtain a hydroxylamine aqueous solution without the organic solvent; and (4) purifying the hydroxylamine aqueous solution from which the organic solvent is removed through ion exchange resin, and removing trace metal ion impurities and anion impurities in the solution to obtain the hydroxylamine aqueous solution applicable to the semiconductor field.

Description

Technical Field

[0001] This invention relates to the field of preparing and purifying high-purity, high-concentration hydroxylamine aqueous solutions, and specifically to a method for preparing hydroxylamine aqueous solutions applicable to the semiconductor field. Background Technology

[0002] Hydroxylamine, as an important chemical intermediate, is used in fine chemical fields such as pharmaceuticals, pesticides, textiles, and electronics. High-purity, high-concentration hydroxylamine aqueous solutions are widely used in semiconductor manufacturing, primarily for post-CMP cleaning of copper / cobalt interconnects, photoresist stripping, and metal surface treatment. It features selective oxide removal without corroding metals, low corrosivity, and environmental friendliness. In semiconductor manufacturing, the concentration of hydroxylamine aqueous solutions needs to reach 50%, and strict requirements are placed on trace impurities in the solution, including metal ions and anions. However, hydroxylamine monomers contain N and O heteroatoms, which can coordinate with metal ions to form stable complexes, making metal ion removal difficult. Furthermore, hydroxylamine monomers are unstable and easily decompose; the decomposition rate accelerates under high concentration and high temperature conditions, resulting in a decrease in the final hydroxylamine yield.

[0003] The patent specification with publication number CN120987276A discloses a method for preparing an ultra-high purity hydroxylamine aqueous solution. The crude hydroxylamine aqueous solution is prepared by neutralization reaction of hydroxylamine salt with organic base, and then ultra-high purity hydroxylamine aqueous solution is prepared by membrane separation and evaporation concentration.

[0004] The patent specification with publication number CN117416933A discloses a method for preparing hydroxylamine aqueous solution by hydroxylamine salt neutralization, wherein the hydroxylamine aqueous solution is prepared by a neutralization reaction and a vacuum distillation process.

[0005] The patent specification with publication number CN101049919A discloses a method for producing high-purity hydroxylamine free base and its aqueous solution, which is prepared by thermal decomposition and sublimation of hydroxylamine phosphate.

[0006] The patent specification with publication number CN1209108A ​​discloses a method for producing free hydroxylamine aqueous solution. The crude hydroxylamine aqueous solution is prepared by acid-base neutralization, and then the hydroxylamine aqueous solution is separated from the salt-containing components by distillation.

[0007] All of the above-mentioned methods for preparing hydroxylamine aqueous solutions involve heating to increase the concentration of hydroxylamine monomers or to purify the aqueous solution. However, high heating temperatures cause a large amount of hydroxylamine monomers to decompose violently, resulting in a low final hydroxylamine yield. Furthermore, the decomposition of hydroxylamine monomers generates a large amount of gas, significantly impacting the safety of the production process. In addition, while high-concentration hydroxylamine aqueous solutions can be prepared through simple neutralization reactions and distillation, the removal of trace impurities is difficult, making it impossible to obtain the high-purity, high-concentration hydroxylamine aqueous solutions required for semiconductor manufacturing. Summary of the Invention

[0008] To address the aforementioned technical problems and shortcomings in this field, the present invention provides a method for preparing an aqueous solution of hydroxylamine applicable to the semiconductor field.

[0009] This invention uses hydroxylamine salt as a raw material, generating an aqueous hydroxylamine solution through an acid-base neutralization reaction; adjusting the mixing ratio of organic solvent and aqueous solution to achieve crystallization and remove salt-containing components from the hydroxylamine aqueous solution; azeotropic distillation of organic solvent and water to increase the hydroxylamine concentration; and resin adsorption to remove residual metal ions and anions from the hydroxylamine aqueous solution. This invention achieves the preparation of high-purity, high-concentration hydroxylamine aqueous solutions (hydroxylamine mass fraction above 50%, single metal ion content less than 5 ppb, and anion concentration below 500 ppb) suitable for the semiconductor field. Through organic solvent-assisted crystallization desalting and azeotropic distillation, mild desalting and concentration of the hydroxylamine aqueous solution can be achieved, avoiding significant decomposition of hydroxylamine monomers. This method has advantages such as mild process conditions, high hydroxylamine monomer yield, and low impurities in the hydroxylamine aqueous solution.

[0010] The specific technical solution is as follows: A method for preparing an aqueous solution of hydroxylamine applicable to the semiconductor field, comprising the following steps: (1) Add an inorganic base aqueous solution to the hydroxylamine salt aqueous solution until the pH of the hydroxylamine salt solution reaches 9~11 (e.g., 10) to obtain crude hydroxylamine aqueous solution; (2) Add an organic solvent to the crude hydroxylamine aqueous solution. The addition of the organic solvent causes a change in the solubility of the salt-containing component, which then crystallizes out. The salt-containing solid is removed by solid-liquid separation to obtain a desalted hydroxylamine solution. (3) The desalted hydroxylamine solution is subjected to vacuum distillation to remove the organic solvent. At the same time, the concentration of hydroxylamine is increased by azeotropic reaction of organic solvent and water to obtain an aqueous solution of hydroxylamine after the organic solvent has been removed. (4) The hydroxylamine aqueous solution after the organic solvent is removed is purified by ion exchange resin to remove trace metal ion impurities and anion impurities in the solution, and a hydroxylamine aqueous solution suitable for semiconductor fields is obtained.

[0011] In some preferred embodiments, in the method for preparing the aqueous hydroxylamine solution applicable to the semiconductor field, in step (1), the hydroxylamine salt includes one or more of hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine phosphate, and hydroxylamine nitrate.

[0012] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (1), the inorganic base includes at least one of sodium hydroxide and potassium hydroxide.

[0013] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (2), the volume of the added organic solvent is 1 to 20 times the volume of the crude hydroxylamine aqueous solution, for example, 6 times, 10 times, 15 times, etc.

[0014] In some preferred embodiments, in the method for preparing the aqueous hydroxylamine solution applicable to the semiconductor field, in step (2), the organic solvent includes one or more of methanol, ethanol, propanol, and isopropanol.

[0015] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (3), the distillation pressure of the vacuum distillation is 100~1000Pa, for example 300Pa, 500Pa, 800Pa, etc.

[0016] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (3), the distillation temperature of the vacuum distillation is 20~100℃, for example 30℃, 40℃, 50℃, 70℃, etc.

[0017] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the ion exchange resin includes one or more of H-type cation exchange resin, OH-type anion exchange resin, and H / OH-type mixed bed ion exchange resin.

[0018] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the metal ion impurity includes lithium ions (Li... + Sodium ions (Na) + ), magnesium ions (Mg 2+ ), aluminum ions (Al) 3+ ), potassium ions (K) + ), calcium ions (Ca 2+ ), titanium ions (Ti 4+ ), vanadium ions (e.g., V) 5+ V 4+ etc.), chromium ions (Cr 3+ ), manganese ions (e.g., Mn) 2+ Mn 4+(etc.), iron ions (Fe) 3+ ), cobalt ions (Co) 2+ Nickel ions (Ni) 2+ ), copper ions (Cu) 2+ ), zinc ions (Zn 2+ ), molybdenum ions (Mo) 6+ ), silver ions (Ag) + ), tin ions (Sn) 4+ Barium ions (Ba) 2+ ), selenium ions (Se) 6+ ), zirconium ions (Zr) 4+ ), mercury ions (Hg) + ), cadmium ions (Cd) 2+ One or more of the following.

[0019] In some preferred embodiments, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the anionic impurity includes nitrate ions (NO3). - ), sulfate ions (SO4) 2- ), phosphate ions (PO4) 3- ), chloride ions (Cl) - One or more of the following.

[0020] In the preparation method of the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the hydroxylamine aqueous solution applicable to the semiconductor field has a hydroxylamine mass fraction of not less than 50%, a single metal ion content of less than 5 ppb, and an anion concentration of less than 500 ppb.

[0021] Furthermore, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the content of a single metal ion in the hydroxylamine aqueous solution applicable to the semiconductor field is less than 3 ppb.

[0022] Furthermore, in the method for preparing the hydroxylamine aqueous solution applicable to the semiconductor field, in step (4), the total content of metal ions in the hydroxylamine aqueous solution applicable to the semiconductor field is less than 10 ppb.

[0023] Compared with the prior art, the beneficial effects of this invention are as follows: A high-purity, high-concentration hydroxylamine aqueous solution (50% by mass, single metal ion content less than 5 ppb, and anion concentration less than 500 ppb) suitable for the semiconductor field was prepared using acid-base neutralization reaction, organic solvent-assisted crystallization for desalination and concentration, and resin adsorption. Room-temperature desalination and low-temperature concentration of the hydroxylamine aqueous solution can be achieved through organic solvent-assisted crystallization desalination and azeotropic distillation, avoiding significant decomposition of hydroxylamine monomers. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.

[0026] In this invention, unless otherwise specified, the unit ppb is equivalent to μg / L.

[0027] Example 1: (1) Dissolve hydroxylamine sulfate and sodium hydroxide in water to form aqueous solutions. Then slowly add the alkaline solution to the hydroxylamine sulfate aqueous solution. Measure the pH of the reaction solution during the addition process. When the pH reaches 9, stop adding the sodium hydroxide alkaline solution to obtain a crude aqueous solution containing hydroxylamine monomer.

[0028] (2) Add ethanol solvent to the above crude aqueous solution. The volume of ethanol solvent is 15 times that of the hydroxylamine aqueous solution. Stir and mix evenly, let stand, and sodium sulfate crystals will precipitate. Filter to remove sodium sulfate and obtain desalted hydroxylamine solution.

[0029] (3) The desalted hydroxylamine solution is subjected to vacuum distillation at a pressure of 300 Pa and a temperature of 50 °C to remove the ethanol solvent. At the same time, the hydroxylamine solution is concentrated by azeotropic distillation of ethanol and water.

[0030] (4) The aqueous hydroxylamine solution after removing the ethanol solvent was purified by passing it through an H / OH type mixed bed ion exchange resin (AmberTecUP6150 H / OH) column to remove trace metal ion impurities and anion impurities in the solution. The aqueous hydroxylamine solution product suitable for the semiconductor field was collected at the resin column outlet, with a hydroxylamine mass fraction of 55.3%.

[0031] Ion chromatography was used to detect the anion concentration in hydroxylamine aqueous solution products, specifically nitrate ions (NO3). - Content 322.5 ppb, sulfate ions (SO4) 2- Content 87.4 ppb, phosphate ions (PO4) 3- Content 25.0 ppb, chloride ions (Cl) - The content was 28.3 ppb. The results of the metal ion concentration detection are shown in Table 1 below.

[0032] Table 1 Example 2: (1) Dissolve hydroxylamine hydrochloride and sodium hydroxide in water to form an aqueous solution. Then slowly add the alkaline solution to the aqueous solution of hydroxylamine hydrochloride. Measure the pH of the reaction solution during the addition process. When the pH reaches 10, stop adding the sodium hydroxide alkaline solution to obtain a crude aqueous solution containing hydroxylamine monomer.

[0033] (2) Add isopropanol solvent to the above crude aqueous solution. The volume of isopropanol solvent is 6 times the volume of hydroxylamine aqueous solution. Stir and mix evenly, let stand, and sodium chloride crystals will precipitate. Filter to remove sodium chloride and obtain desalted hydroxylamine solution.

[0034] (3) The desalted hydroxylamine solution was subjected to vacuum distillation at a pressure of 100 Pa and a temperature of 50 °C to remove the isopropanol solvent. At the same time, the hydroxylamine solution was concentrated by azeotropic distillation of isopropanol and water.

[0035] (4) The aqueous hydroxylamine solution after removing isopropanol solvent is purified by passing it through a series adsorption column of H / OH type mixed bed ion exchange resin (AmberTec UP6150 H / OH) and OH type ion exchange resin (AmberTec UP550 OH) to remove trace metal ion impurities and anion impurities in the solution. The aqueous hydroxylamine solution product suitable for the semiconductor field is collected at the resin column outlet, with a hydroxylamine mass fraction of 50.8%.

[0036] Ion chromatography was used to detect the anion concentration in hydroxylamine aqueous solution products, specifically nitrate ions (NO3). - Content 133.5 ppb, sulfate ions (SO4) 2- Content 45.1 ppb, phosphate ions (PO4) 3- Content 20.6 ppb, chloride ions (Cl) - The content was 17.3 ppb. The results of the metal ion concentration detection are shown in Table 2 below.

[0037] Table 2 Example 3: (1) Dissolve hydroxylamine sulfate and potassium hydroxide in water to form aqueous solutions. Then slowly add the alkaline solution to the hydroxylamine sulfate aqueous solution. Measure the pH of the reaction solution during the addition process. When the pH reaches 10, stop adding the potassium hydroxide alkaline solution to obtain a crude aqueous solution containing hydroxylamine monomer.

[0038] (2) Add methanol solvent to the above crude aqueous solution. The volume of methanol solvent is 10 times that of hydroxylamine aqueous solution. Stir and mix evenly, let stand, and potassium sulfate crystals will precipitate. Filter to remove potassium sulfate.

[0039] (3) The desalted hydroxylamine solution was subjected to vacuum distillation at a pressure of 300 Pa and a temperature of 40 °C to remove the methanol solvent. At the same time, the hydroxylamine solution was concentrated by azeotropic distillation of methanol and water.

[0040] (4) The hydroxylamine aqueous solution after removing methanol solvent was purified by passing it through a series adsorption column of H / OH type mixed bed ion exchange resin (AmberTec UP6150 H / OH) and OH type ion exchange resin (AmberTec UP550 OH) to remove trace metal ion impurities and anion impurities in the solution. The hydroxylamine aqueous solution product suitable for the semiconductor field was collected at the resin column outlet, with a hydroxylamine mass fraction of 62.8%.

[0041] Ion chromatography was used to detect the anion concentration in hydroxylamine aqueous solution products, specifically nitrate ions (NO3). - Content 182.2 ppb, sulfate ions (SO4) 2- Content 58.4 ppb, phosphate ions (PO4) 3- The content was 16.3 ppb, and the chloride ion content was 16.3 ppb. - The content was 20.2 ppb. The results of the metal ion concentration detection are shown in Table 3 below.

[0042] Table 3 Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for preparing an aqueous solution of hydroxylamine applicable to the semiconductor field, characterized in that, Including the following steps: (1) Add an inorganic base solution to the hydroxylamine salt solution until the pH of the hydroxylamine salt solution reaches 9-11 to obtain crude hydroxylamine solution; (2) Add an organic solvent to the crude hydroxylamine aqueous solution. The addition of the organic solvent causes a change in the solubility of the salt-containing component, which then crystallizes out. The salt-containing solid is removed by solid-liquid separation to obtain a desalted hydroxylamine solution. (3) The desalted hydroxylamine solution is subjected to vacuum distillation to remove the organic solvent. At the same time, the concentration of hydroxylamine is increased by azeotropic reaction of organic solvent and water to obtain an aqueous solution of hydroxylamine after the organic solvent has been removed. (4) The hydroxylamine aqueous solution after the organic solvent is removed is purified by ion exchange resin to remove trace metal ion impurities and anion impurities in the solution, and a hydroxylamine aqueous solution suitable for semiconductor fields is obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the hydroxylamine salt includes one or more of hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine phosphate, and hydroxylamine nitrate.

3. The preparation method according to claim 1, characterized in that, In step (1), the inorganic base includes at least one of sodium hydroxide and potassium hydroxide.

4. The preparation method according to claim 1, characterized in that, In step (2), the volume of the added organic solvent is 1 to 20 times the volume of the crude hydroxylamine aqueous solution.

5. The preparation method according to claim 1, characterized in that, In step (2), the organic solvent includes one or more of methanol, ethanol, propanol, and isopropanol.

6. The preparation method according to claim 1, characterized in that, In step (3), the distillation pressure of the vacuum distillation is 100~1000Pa and the distillation temperature is 20~100℃.

7. The preparation method according to claim 1, characterized in that, In step (4), the ion exchange resin includes one or more of H-type cation exchange resin, OH-type anion exchange resin, and H / OH-type mixed bed ion exchange resin.

8. The preparation method according to claim 1, characterized in that, In step (4), the metal ion impurities include one or more of the following: lithium ion, sodium ion, magnesium ion, aluminum ion, potassium ion, calcium ion, titanium ion, vanadium ion, chromium ion, manganese ion, iron ion, cobalt ion, nickel ion, copper ion, zinc ion, molybdenum ion, silver ion, tin ion, barium ion, selenium ion, zirconium ion, mercury ion, and cadmium ion.

9. The preparation method according to claim 1, characterized in that, In step (4), the anionic impurities include one or more of nitrate ions, sulfate ions, phosphate ions, and chloride ions.

10. The preparation method according to claim 1, characterized in that, In step (4), the hydroxylamine aqueous solution applicable to the semiconductor field has a hydroxylamine mass fraction of not less than 50%, a single metal ion content of less than 5 ppb, and an anion concentration of less than 500 ppb.

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