A detection method for electronic grade octafluorocyclopentene

Abstract

The invention discloses a detection method for electronic grade octafluorocyclopentene. The pre-cutting (removal) column is about 1m long and is a Hastelloy C-grade column with an inner diameter of about 2mm. Silica Gel with a particle size of 0.18mm-0.25mm is filled therein, or other equivalent chromatographic columns are used. The pre-cutting (removal) sampling method specified in GB / T 28726 is used to determine the contents of hydrogen, oxygen+argon, nitrogen, carbon monoxide, methane and other fluorocarbon compounds in the octafluorocyclopentene. The provisions of GB / T 5832.2 are used to determine the water content in the octafluorocyclopentene. An inductively coupled plasma mass spectrometry method is used to determine the contents of metal elements such as sodium, zinc, chromium, copper, nickel and iron in the octafluorocyclopentene. Finally, the purity of the octafluorocyclopentene is accurately determined by a difference subtraction method.

Description

Technical Field

[0001] The invention belongs to the field of analytical chemistry, and in particular relates to a method for detecting electronic-grade octafluorocyclopentene. Background Art

[0002] High purity octafluorocyclopentene (C 5 F 8 ) is widely used in the etching process in the manufacturing process of semiconductor devices, especially for the size and selectivity of the smallest geometric features (such as the width of interconnects, contacts, trenches, etc.). As the next generation of etching gas and one of the most attractive raw materials for electronic devices, it is considered to have a competitive advantage.

[0003] Patent document CN101529219B discloses a method for detecting leakage of a fluoroolefin composition and a sensor used therefor. In particular, the method is particularly useful for detecting leakage of a fluoroolefin refrigerant composition from a motor vehicle cooling system. Such fluoroolefin refrigerant compositions have a double bond structure, which makes them particularly suitable for use with the following sensing technologies, including: infrared sensors, ultraviolet sensors, NIR sensors, ion mobility or plasma chromatography, gas chromatography, refractometers, mass spectrometers, high temperature thick film sensors, thin film field effect sensors, pellistor sensors, Taguchi sensors, and quartz microbalance sensors.

[0004] Patent document TWI542874B provides a method for detecting fluoride, hydrocarbon fluoride, such as C 5 F 8 or C 4 F 6 Methods and sensors for detecting fluoride, chloride or bromide of a substance that can be detected with speed and high sensitivity at room temperature or closer.

[0005] However, there are few descriptions and regulations on the detection methods specifically for electronic grade octafluorocyclopentene in the existing public technologies. Summary of the invention

[0006] The purpose of the present invention is to provide a method for detecting electronic grade octafluorocyclopentene, which adopts inductively coupled plasma mass spectrometry to determine the contents of metal elements such as sodium, zinc, chromium, copper, nickel, iron and the like in octafluorocyclopentene, and adopts a difference subtraction method to determine the purity of octafluorocyclopentene.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for detecting electronic grade octafluorocyclopentene, using a pre-cut (removal) column: a Hastelloy C-grade column with a length of about 1 m and an inner diameter of about 2 mm, filled with Silica Gel with a particle size of 0.18 mm to 0.25 mm, or other equivalent chromatographic columns;

[0009] Chromatographic column I: 316L stainless steel column with a length of about 3.5m and an inner diameter of about 2mm, filled with 5A molecular sieve with a particle size of 0.18mm to 0.25mm, or other equivalent chromatographic columns;

[0010] Chromatographic column II: A capillary column with a length of about 60m, an inner diameter of about 0.53mm, and coated with dimethylsiloxane, or other equivalent chromatographic columns.

[0011] Furthermore, the chromatographic column I is used to analyze the contents of hydrogen, oxygen+argon, nitrogen, methane, and carbon monoxide.

[0012] Furthermore, the chromatographic column II is used to analyze the content of other fluorocarbon compounds.

[0013] Furthermore, the contents of hydrogen, oxygen + argon, nitrogen, carbon monoxide, methane and other fluorocarbon compounds in octafluorocyclopentene were determined according to the pre-cutting (removal) sampling method specified in GB / T 28726.

[0014] Furthermore, the water content in octafluorocyclopentene was determined according to the provisions of GB / T 5832.2.

[0015] Furthermore, the content of metal elements such as sodium, zinc, chromium, copper, nickel, and iron in octafluorocyclopentene was determined by inductively coupled plasma mass spectrometry, and the specific steps are as follows:

[0016] Step 1: Accurately weigh the initial mass of the absorption bottle and record M0.

[0017] Step 2: After the absorption bottle is placed in liquid nitrogen, slowly pass the octafluorocyclopentene sample through the absorption bottle. When the amount of octafluorocyclopentene absorbed in the absorption bottle is greater than 10g (accurate to 0.01g), stop absorbing. Accurately weigh the total mass of the absorption bottle and the sample, and record M1. The mass of the sample in the absorption bottle is calculated based on the difference in mass before and after sampling.

[0018] Step 3: Place the absorption bottle in boiling water, remove the absorption bottle after complete vaporization, and add about 10g of 1% nitric acid. Accurately weigh the total mass of the absorption bottle and 1% nitric acid, and record M2. The solution in the absorption bottle is the sample solution for determining metal elements.

[0019] Step 4: Turn on the instrument according to the operating procedures of the inductively coupled plasma mass spectrometer. When the machine is in a stable state, use the standard addition method to develop a standard curve.

[0020] Step 5: Determination of 1% nitric acid and samples.

[0021] Step 6: Calculate the results.

[0022] The metal element content in octafluorocyclopentene is calculated according to formula (3):

[0023] Wi=(W1-W2)*(M2-M0) / (M1-M0)················(1)

[0024] Where:

[0025] Wi——Metal content in octafluorocyclopentene, 10 -9 ;

[0026] W1——Metal element content of solution in the absorption bottle, 10 -9 ;

[0027] W2——Metal content in 1% nitric acid, 10 -9 ;

[0028] M0——initial mass of the absorption bottle, in grams;

[0029] M1——Total mass of the absorption bottle and octafluorocyclopentene sample, in grams;

[0030] M2——Total mass of the absorption bottle and 1% nitric acid, in grams.

[0031] The purity of the octafluorocyclopentene is determined by subtraction method:

[0032] The total impurity content Φ7 is calculated according to formula (1):

[0033] Φ7=Φ1 +Φ2 +Φ3 +Φ4 +Φ5 +Φ6............ (2)

[0034] Where:

[0035] Φ1——Oxygen + Argon content (volume fraction), 10 -6 ;

[0036] Φ2——Nitrogen content (volume fraction), 10 -6 ;

[0037] Φ3——Hydrogen content (volume fraction), 10 -6 ;

[0038] Φ4——Carbon monoxide content (volume fraction), 10 -6 ;

[0039] Φ5——methane content (volume fraction), 10 -6 ;

[0040] Φ6——Water content (volume fraction), 10 -6

[0041] The purity of octafluorocyclopentene is calculated according to formula (2):

[0042] Φ =100-Φ7 ×10 -4 ................... (3)

[0043] Where:

[0044] Φ——Octafluorocyclopentene purity (volume fraction), 10 -2 .

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The invention provides a detection method for electronic grade octafluorocyclopentene. The method has the technical characteristics of high sensitivity, good stability and low inspection cost, and is suitable for use by industrial enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0048] Figure 1 This is a schematic diagram of the test process of this method.

[0049] The accompanying drawings are marked as:

[0050] ①——Nitrogen cylinder

[0051] ②——Octafluorocyclopentene cylinder

[0052] ③——3nm filter

[0053] ④——Pneumatic valve

[0054] ⑤——Pressure regulating valve

[0055] ⑥——PFA valve

[0056] ⑦——Absorption bottle

[0057] Figure 2 is the chromatographic analysis spectrum of column I;

[0058] Figure 3 is the chromatographic analysis spectrum of column II;

[0059] Figure 4 An interface diagram is shown for the water content in octafluorocyclopentene. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] Comparative Example 1

[0062] Using 1% HNO 3 As a sample test.

[0063] Example 1

[0064] Step 1: Accurately weigh the initial mass of the absorption bottle and record M0.

[0065] Step 2: After the absorption bottle is placed in liquid nitrogen, slowly pass the octafluorocyclopentene sample through the absorption bottle. When the amount of octafluorocyclopentene absorbed in the absorption bottle is greater than 10g (accurate to 0.01g), stop absorbing. Accurately weigh the total mass of the absorption bottle and the sample, and record M1. The mass of the sample in the absorption bottle is calculated based on the difference in mass before and after sampling.

[0066] Step 3: Place the absorption bottle in boiling water, remove the absorption bottle after complete vaporization, and add about 10g of 1% nitric acid. Accurately weigh the total mass of the absorption bottle and 1% nitric acid, and record M2. The solution in the absorption bottle is the sample solution for determining metal elements.

[0067] Step 4: Turn on the instrument according to the operating procedures of the inductively coupled plasma mass spectrometer. When the machine is in a stable state, use the standard addition method to develop a standard curve.

[0068] Step 5: Determination of 1% nitric acid and samples.

[0069] Step 6: Calculate the results.

[0070] The metal element content in octafluorocyclopentene is calculated according to formula (3):

[0071] Wi=(W1-W2)*(M2-M0) / (M1-M0) ····················(1)

[0072] Where:

[0073] Wi——Metal content in octafluorocyclopentene, 10 -9 ;

[0074] W1——Metal element content of solution in the absorption bottle, 10 -9 ;

[0075] W2——Metal content in 1% nitric acid, 10-9 ;

[0076] M0——initial mass of the absorption bottle, in grams;

[0077] M1——Total mass of the absorption bottle and octafluorocyclopentene sample, in grams;

[0078] M2 – total mass of absorption bottle and 1% nitric acid, in grams.

[0079] The metal element concentration test results of Comparative Example 1 and Example 1 are shown in the following table:

[0080]

[0081]

[0082] The names of the articles of the present invention described above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or direct / indirect applications in other related technical fields, under the inventive concept of the present invention are included in the patent protection scope of the present invention.

Claims

1. A method for detecting electronic grade octafluorocyclopentene, It is characterized in that Pre-cut column specifications: Hastelloy C-grade column with a length of about 1m and an inner diameter of about 2mm, filled with Silica Gel with a particle size of 0.18mm to 0.25mm, or other equivalent chromatographic columns; Chromatographic column I: 316L stainless steel column with a length of about 3.5m and an inner diameter of about 2mm, filled with 5A molecular sieve, or other equivalent chromatographic columns; Chromatographic column II: a capillary column with a length of about 60m, an inner diameter of about 0.53mm, and coated with dimethylsiloxane, or other equivalent chromatographic columns; The content of metal elements sodium, zinc, chromium, copper, nickel and iron in octafluorocyclopentene was determined by inductively coupled plasma mass spectrometry. The specific steps are as follows: Step 1: Accurately weigh the initial mass of the absorption bottle and record M0; Step 2: After the absorption bottle is placed in liquid nitrogen, slowly pass the octafluorocyclopentene sample through the absorption bottle. When the amount of octafluorocyclopentene absorbed in the absorption bottle is greater than 10g, stop absorbing, accurately weigh the total mass of the absorption bottle and the sample, and record M1. The mass of the sample in the absorption bottle is obtained based on the difference in mass before and after sampling; Step 3: Put the absorption bottle into boiling water, remove the absorption bottle after complete vaporization, add about 10g 1% nitric acid, accurately weigh the total mass of the absorption bottle and 1% nitric acid, and record M2. The solution in the absorption bottle is the sample solution for determining metal elements; Step 4: Turn on the instrument according to the operating procedures of the inductively coupled plasma mass spectrometer. When the machine is in a stable state, use the standard addition method to develop a standard curve; Step 5: Determination of 1% nitric acid and samples.

2. A method for detecting electronic grade octafluorocyclopentene according to claim 1, It is characterized in that The chromatographic column I is used to analyze the contents of hydrogen, oxygen+argon, nitrogen, methane and carbon monoxide.

3. A method for detecting electronic grade octafluorocyclopentene according to claim 1, It is characterized in that The particle size of the 5A molecular sieve contained in the chromatographic column I is 0.18 mm to 0.25 mm.

4. A method for detecting electronic grade octafluorocyclopentene according to claim 1, It is characterized in that The chromatographic column II is used to analyze the content of other fluorocarbon compounds.

5. A method for detecting electronic grade octafluorocyclopentene according to claim 1, It is characterized in that The metal element content in octafluorocyclopentene is calculated according to formula (1): Wi=(W1-W2)*(M2-M0) / (M1-M0) (1) Where: Wi ——Metal content in octafluorocyclopentene, 10 -9 ; W1——Metal element content of solution in the absorption bottle, 10 -9 ; W2 ——Metal content in 1% nitric acid, 10 -9 ; M0 ——initial mass of the absorption bottle, in grams; M1 ——Total mass of absorption bottle and octafluorocyclopentene sample, in grams; M2 ——Total mass of absorption bottle and 1% nitric acid, in grams.

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