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CN-121994904-A - Method for determining trace metal impurities in electronic grade hydroxylamine

CN121994904ACN 121994904 ACN121994904 ACN 121994904ACN-121994904-A

Abstract

The invention discloses a method for determining trace metal impurities in electronic-grade hydroxylamine, which comprises the steps of preparing a composite extracting solution which has a pH value of 5.5+/-0.2 and contains ammonium citrate, ammonium acetate and EDTA, diluting a hydroxylamine sample, effectively inhibiting hydroxylamine from decomposing and stabilizing metal ions, combining a triple quadrupole inductively coupled plasma mass spectrometry technology, utilizing the functions of cooling and atomizing and a dynamic reaction tank to eliminate multi-atom ion interference, and finally quantifying by adopting a standard curve method of matrix matching. The invention solves the technical problems of low metal ion detection recovery rate and poor accuracy caused by chemical instability of electronic-grade hydroxylamine, has the advantages of safe operation, high sensitivity, stable recovery rate and the like, and provides a reliable analysis means for quality control of key chemicals in the semiconductor manufacturing process.

Inventors

  • LI JINE
  • BAO ZONGBI
  • LU PING
  • REN QILONG

Assignees

  • 浙江大学衢州研究院

Dates

Publication Date
20260508
Application Date
20260204

Claims (9)

  1. 1. A method for determining trace metal impurities in electronic grade hydroxylamine comprising the steps of: (1) Dissolving ammonium citrate, ammonium acetate and EDTA in ultrapure water to obtain a solution containing 0.05+/-0.01M ammonium citrate, 0.05+/-0.01M ammonium acetate and 0.01+/-0.001M EDTA, and then regulating the pH of the solution to 5.5+/-0.2, preferably 5.5+/-0.1, by using ammonia water and/or acetic acid to obtain a composite extracting solution; (2) Diluting the electronic-grade hydroxylamine sample to be tested by using the composite extracting solution, wherein the dilution factor is 50-100 times, so as to ensure the stability of the metal ion form and obtain a sample test solution; (3) Sample detection, namely analyzing sample test liquid by adopting a triple quadrupole inductively coupled plasma mass spectrometer provided with a Peltier cooling atomization system PC3 and a dynamic reaction tank DRC-MS/MS; (4) And (3) quantitatively analyzing, namely preparing a series of metal concentration gradient standard calibration liquids from hydroxylamine solution which does not detect metal ions according to the step (2) by adopting a matrix matching principle, detecting the standard calibration liquids according to the step (3), establishing a calibration curve, and quantifying target metal elements of the electronic-grade hydroxylamine sample according to the calibration curve.
  2. 2. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1, wherein the sample test solution and the standard calibration solution are held in a PFA container pretreated by distillation washing with nitric acid solution having a volume concentration of 5% or more at 150 to 180 ℃ for 12 to 24 hours, followed by rinsing with ultrapure water until the background metal concentration of the PFA container is confirmed to be lower than 0.02 ng.L -1 by ICP-MS detection.
  3. 3. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1 or 2, wherein said ultrapure water has a resistivity of not less than 18.2mΩ -cm at 25 ℃.
  4. 4. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1, wherein in step (3), the working temperature of Peltier cooling atomizing system PC3Peltier is set at-5 ± 1 ℃.
  5. 5. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1, wherein in step (3), the reaction gas in the dynamic reaction tank contains oxygen and ammonia.
  6. 6. The method for determining trace metal impurities in electronic grade hydroxylamine of claim 5, wherein in step (3), the flow rate of oxygen is 0.4-0.6 mL min -1 and the flow rate of ammonia is 0.3-0.6 mL min -1 .
  7. 7. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1, wherein in step (4), the calibration curve is constructed using a weighted least squares method, weight = 1/concentration ‍, and quadratic polynomial correction is used to compensate for the nonlinearity of the high concentration region when extrapolating the curve.
  8. 8. The method for determining trace metal impurities in electronic grade hydroxylamine of claim 1, wherein in step (4) the target metal elements comprise one or more of sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, selenium, molybdenum, silver, tin, barium.
  9. 9. The method for determining trace metal impurities in electronic grade hydroxylamine according to claim 1, wherein the entire detection procedure for determining trace metal impurities in electronic grade hydroxylamine is performed under an ultra clean environment of ISO Class 5 or higher.

Description

Method for determining trace metal impurities in electronic grade hydroxylamine Technical Field The invention relates to the technical field of semiconductor ultra-high purity electronic chemical analysis, in particular to a method for determining trace metal impurities in electronic-grade hydroxylamine. Background Electronic grade hydroxylamine (NH 2 OH) is used as a key cleaning agent in the Chemical Mechanical Polishing (CMP) process of semiconductor copper interconnection, and trace metal impurities (such as Fe, cu, ni, zn and the like) directly influence the gate oxide integrity and the final yield of a chip, so that metal ions in the electronic grade hydroxylamine need to be strictly controlled in ppb or even ppt level. Currently, for detecting trace metal impurities in electronic grade hydroxylamine, an inductively coupled plasma mass spectrometry (ICP-MS) method is commonly adopted in the industry, and has extremely low detection limit (up to ng/L or ppt level), wide linear dynamic range, multi-element simultaneous analysis capability and higher analysis efficiency. For example, patent specification publication CN120987276A, CN120987277a discloses the use of Inductively Coupled Plasma Mass Spectrometry (ICPMS) to detect metal ion content in aqueous hydroxylamine samples. However, the inherent strong reducibility and chemical instability of hydroxylamine bring great challenges to the analysis of trace metals, such as the fact that the traditional high temperature/strong acid digestion process is extremely easy to trigger the violent decomposition of hydroxylamine, and has great potential safety hazards, the metal ions are easy to change in valence state in the sample detection process after the dilution of ultrapure water, so that the container wall is adsorbed or hydroxylamine-metal complexes are formed, the metal ions are lost and the morphology is distorted, in addition, the ionized ring node of the high-concentration hydroxylamine body per se can form ArN +、ArO+、ArNH+、ArNO+ and other polyatomic ions with argon (Ar) when the high-concentration hydroxylamine body per se is measured by ICP-MS, and the accurate measurement of key metal elements such as Mn, fe, cu, zn, as, V is seriously interfered. Therefore, it is important to develop a method capable of safely, accurately and highly sensitively determining trace metals in electronic grade hydroxylamine. Disclosure of Invention In view of the above-described technical problems and deficiencies in the art, the present invention provides a method for determining trace metal impurities in electronic grade hydroxylamine. The invention constructs a solution integrating in-situ stability, matrix matching and multi-mode interference elimination, and realizes the safe, accurate and high-sensitivity detection of 18 metal elements. The method provided by the invention has the advantages that the recovery rate of the metal element is stabilized at 90% -110% in ISOClass100,100 ultra-clean environment, the detection limit of the method is less than or equal to 0.1 mug/kg, and a reliable analysis technical support is provided for the quality control closed loop of the semiconductor advanced process. The specific technical scheme is as follows: A method for determining trace metal impurities in electronic grade hydroxylamine comprising the steps of: (1) Ammonium citrate, ammonium acetate and ethylenediamine tetraacetic acid (EDTA) were dissolved in ultrapure water to obtain a solution containing 0.05.+ -. 0.01M ammonium citrate, 0.05.+ -. 0.01.+ -. M ammonium acetate and 0.01.+ -. 0.001M EDTA, and then the pH of the solution was adjusted to 5.5.+ -. 0.2, preferably 5.5.+ -. 0.1, with ammonia and/or acetic acid to obtain a composite extract. The composite extracting solution can effectively inhibit the decomposition of hydroxylamine, and stabilize trace metal ions through chelation to prevent the adsorption or precipitation of the trace metal ions. (2) And diluting the electronic-grade hydroxylamine sample to be detected by using the composite extracting solution, wherein the dilution multiple is 50-100 times, and the stability of the metal ion form is ensured, so that the sample test solution is obtained. (3) Sample detection the sample test solution is analyzed by a triple quadrupole inductively coupled plasma mass spectrometer (ICP-MS/MS, such as PE-5000G and the like) equipped with a Peltier cooling atomization system PC3 and a dynamic reaction cell DRC-MS/MS. The triple quadrupole inductively coupled plasma mass spectrometer realizes low-matrix effect and high-sensitivity detection of the metal impurities of the sample through the synergistic effect of the three sections of cooling atomization PC3 Peltier-DRC-MS/MS. (4) And (3) quantitatively analyzing, namely preparing a series of metal concentration gradient standard calibration liquids (standard solutions) from hydroxylamine solutions which do not detect metal ions according to the step (2), detecting the s