Method for testing azodiisobutyronitrile in photoresist resin

Abstract

The invention provides a method for testing azodiisobutyronitrile in photoresist resin, which comprises the following steps of: pretreating a photoresist resin sample to obtain filtrate, determining the content of the azodiisobutyronitrile in the filtrate by adopting a gas chromatography-mass spectrometry detection method, and calculating to obtain the content of the azodiisobutyronitrile in the photoresist resin sample. The method comprises the following steps: ultrasonically dissolving a photoresist resin sample in tetrahydrofuran, filtering through a filter membrane filter to obtain filtrate, separating azodiisobutyronitrile through a gas chromatographic column, ionizing the separated component into ions in a mass spectrometer, and separating and detecting according to the mass-to-charge ratio of the ions. The pretreatment step of the photoresist resin sample is simple, and the tested component is fully dissolved in the solvent through the pretreatment, so that the interference of other impurities in the sample is reduced; and the test method provided by the invention is high in precision and good in accuracy, and the test results of high-concentration and low-concentration actual samples are relatively stable.

Description

Technical Field

[0001] This invention belongs to the field of photoresist raw material detection technology, and in particular relates to a test method for azobisisobutyronitrile in photoresist resin. Background Technology

[0002] Photoresist is a key material in semiconductor manufacturing, used to transfer intricate patterns on silicon wafers. The performance of photoresist directly affects the integration density and performance of integrated circuits. Among the components of photoresist, photoresist resin, as the main film-forming substance, plays a decisive role in the overall performance of the photoresist. The synthesis of photoresist resin typically requires an initiator to initiate the polymerization reaction; azobisisobutyronitrile (AIBN) is widely used due to its highly efficient initiation activity.

[0003] However, residual azobisisobutyronitrile (AIBN) from the polymerization reaction can adversely affect the application of photoresist resins. Residual AIBN not only affects the chemical stability of the photoresist but may also cause pattern defects during subsequent photolithography processes, reducing the yield of integrated circuits. Furthermore, AIBN has a certain degree of toxicity, and its residues may pose a threat to the health of operators and the environment.

[0004] Currently, the methods for detecting azobisisobutyronitrile (AIB) residues in photoresist resins have certain limitations. If the photoresist resin sample contains a complex and diverse range of other organic impurities, the qualitative accuracy, resolution, and sensitivity of traditional gas chromatography (GC) and high-performance liquid chromatography (HPLC) methods are insufficient, and the target analytes cannot be quickly identified.

[0005] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a test method for azobisisobutyronitrile in photoresist resin, so as to solve the problems in the prior art.

[0007] To achieve the above and other related objectives, the present invention provides a method for testing azobisisobutyronitrile (AIBN) in photoresist resin. The method involves pretreating a photoresist resin sample to obtain a filtrate, then using gas chromatography-mass spectrometry (GC-MS) to determine the AIBN content in the filtrate, and finally calculating the AIBN content in the photoresist resin sample.

[0008] Preferably, the pretreatment includes the following steps: ultrasonically dissolving the photoresist resin sample in tetrahydrofuran to obtain a sample solution, and then taking a certain amount of the sample solution and filtering it using a membrane filter to obtain a filtrate.

[0009] Preferably, the mass-to-volume ratio of the photoresist resin sample to the tetrahydrofuran is 1:(8-12)(g / mL).

[0010] Preferably, the pore size of the membrane filter is 0.22 μm to 0.45 μm.

[0011] Preferably, the gas chromatography-mass spectrometry detection method includes the following steps:

[0012] S1. Preparation of standard solutions: Prepare a series of azobisisobutyronitrile standard solutions of various concentrations;

[0013] S2. The filtrate and a series of concentrations of azobisisobutyronitrile standard solutions were analyzed by gas chromatography-mass spectrometry, and quantitative analysis was performed by external standard curve method to obtain the content of azobisisobutyronitrile in the filtrate.

[0014] Preferably, the gas chromatographic column used in step S2 is an HP-5ms capillary column.

[0015] More preferably, the chromatographic column has the following specifications: a length of 30m, an inner diameter of 0.25mm, and a film thickness of 0.25μm.

[0016] Preferably, in step S2, the injection port temperature of the gas chromatograph is 260℃~300℃, the injection volume is 1μL, the split ratio is 20:1~50:1, the column flow rate is 1.00~2.00mL / min, and the solvent delay time is 2.3min.

[0017] Preferably, in step S2, the gas chromatograph is heated from the initial temperature at a rate of 20°C / min to 30°C / min, wherein the initial temperature is 40°C to 60°C.

[0018] Preferably, the mass spectrometry scanning range in step S2 is 29–550 m / z.

[0019] Preferably, the mass spectrometry scanning mode in step S2 is a simultaneous full scan (SCAN) and selected ion monitoring (SIM) mode.

[0020] As described above, the method for testing azobisisobutyronitrile in photoresist resin of the present invention has the following beneficial effects:

[0021] In this invention, the photoresist resin sample is ultrasonically dissolved in tetrahydrofuran, then filtered through a membrane filter to obtain the filtrate. The filtrate is then separated by gas chromatography to obtain azobisisobutyronitrile (AIBN). The separated components are ionized into ions in a mass spectrometer, and then separated and detected based on the mass-to-charge ratio of the ions. The pretreatment steps for the photoresist resin sample in this invention are simple. After pretreatment, the analyte is fully dissolved in the solvent, reducing interference from other impurities in the sample. Furthermore, the testing method in this invention has high precision and good accuracy, and the test results are relatively stable for both high-concentration and low-concentration actual samples. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0023] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0024] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0025] This invention provides a method for testing azobisisobutyronitrile (AIBN) in photoresist resin. The method involves pretreating a photoresist resin sample to obtain a filtrate, then using gas chromatography-mass spectrometry (GC-MS) to determine the content of AIBN in the filtrate, and finally calculating the content of AIBN in the photoresist resin sample.

[0026] Specifically, gas chromatography-mass spectrometry (GC-MS) involves separating the sample in a chromatographic column, converting it into ions using an ion source, and then separating and detecting these ions according to their mass-to-charge ratio in a mass spectrometer. The sample is analyzed by analyzing the resulting mass spectrum. GC-MS is used to determine the content of azobisisobutyronitrile (AIBN) in the filtrate, in mg / L, and then the content of AIBN in the photoresist resin sample is calculated, in mg / kg.

[0027] As an example, the pretreatment includes the following steps: ultrasonically dissolving the photoresist resin sample in tetrahydrofuran to obtain a sample solution, and then taking a certain amount of the sample solution and filtering it using a membrane filter to obtain a filtrate.

[0028] Specifically, tetrahydrofuran can dissolve photoresist resin well. Photoresist resin may contain some insoluble particles or polymer clusters, which need to be removed by filtration to prevent clogging of the instrument's injection needle.

[0029] As an example, the mass-to-volume ratio of the photoresist resin sample to tetrahydrofuran is 1:(8-12)(g / mL).

[0030] Specifically, the mass-to-volume ratio between the photoresist resin sample and tetrahydrofuran can be any value within the range of 1:8 (g / mL), 1:9 (g / mL), 1:10 (g / mL), 1:11 (g / mL), 1:12 (g / mL), etc.

[0031] As an example, the pore size of the membrane filter is 0.22 μm to 0.45 μm.

[0032] Specifically, the pore size of the membrane filter can include any value within a range such as 0.22μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, and 0.45μm. The smaller the pore size of the membrane filter, the smaller the impurities it can remove, but this may also pose a risk of clogging the membrane. Considering all factors, in this specific embodiment of the invention, the pore size of the membrane filter is selected as 0.45μm.

[0033] As an example, the gas chromatography-mass spectrometry detection method includes the following steps:

[0034] S1. Preparation of standard solutions: Prepare a series of azobisisobutyronitrile standard solutions of various concentrations;

[0035] S2. The filtrate and a series of concentrations of azobisisobutyronitrile standard solutions were analyzed by gas chromatography-mass spectrometry, and the external standard curve method was used for quantitative analysis to obtain the content of azobisisobutyronitrile in the filtrate.

[0036] Specifically, first, a series of standard solutions with known concentrations need to be prepared. These standard solutions contain the analyte, and their concentrations should cover the low to high values ​​within the expected measurement range. Then, each standard solution is measured, and its response signal is recorded. A standard curve is plotted based on the relationship between the response signal and the concentration of the standard solution, and a linear regression equation is determined. Then, the same measurement is performed on the sample solution with unknown concentration to obtain its response signal. The response signal is substituted into the linear regression equation to calculate its corresponding concentration. If the response signal of the sample exceeds the range of the standard curve, it needs to be diluted and measured again.

[0037] As an example, the gas chromatography column used in step S2 is an HP-5ms capillary column.

[0038] Specifically, in a specific embodiment of the present invention, the specifications of the chromatographic column are: length of 30m, inner diameter of 0.25mm, and membrane thickness of 0.25μm.

[0039] As an example, in step S2, the injection port temperature of the gas chromatograph is 260℃~300℃, the injection volume is 1μL, the split ratio is 20:1~50:1, the column flow rate is 1.00~2.00mL / min, and the solvent delay time is 2.3min.

[0040] Specifically, the injection port temperature of the gas chromatograph can be any value within the range of 260℃, 270℃, 280℃, 290℃, 300℃, etc., the split ratio can be any value within the range of 20:1, 30:1, 40:1, 50:1, etc., and the column flow rate can be any value within the range of 1.00mL / min, 1.25mL / min, 1.5mL / min, 1.75mL / min, 2.00mL / min, etc.

[0041] As an example, in step S2, the gas chromatograph is heated from the initial temperature at a heating rate of 20℃ / min to 30℃ / min, wherein the initial temperature is 40℃ to 60℃.

[0042] Specifically, the heating rate can include any value in the range of 20, 22, 24, 26, 28, 30, etc., and the initial temperature can include any value in the range of 40, 45, 50, 55, 60, etc.

[0043] Preferably, in a specific embodiment of the present invention, the temperature program for gas chromatography is as follows: the initial temperature is 50°C, held at the initial temperature for 1 min, then increased to 320°C at a heating rate of 30°C / min, and held for 3 min.

[0044] As an example, the mass spectrometry scanning range in step S2 is 29–550 m / z.

[0045] Specifically, the scanning range of mass spectrometry can include values ​​within any range such as 29 m / z, 50 m / z, 100 m / z, 200 m / z, 300 m / z, 400 m / z, 500 m / z, and 550 m / z.

[0046] As an example, the mass spectrometry scanning mode in step S2 is simultaneous full scan mode (SCAN) and selected ion monitoring (SIM) mode.

[0047] Specifically, in full scan mode, the mass spectrometer detects all ions within the set mass range and generates a complete mass spectrum; in selected ion monitoring mode, the mass spectrometer only detects ions with a specific m / z value preset by the user, ignoring other ions; full scan mode provides qualitative information, while SIM mode provides quantitative information, and the combination of the two can simultaneously perform compound identification and quantitative analysis.

[0048] In specific embodiments of the present invention, the characteristic ion of azobisisobutyronitrile can be selected as 69.1, 54.1, or 41.0. m / z 69.1: This mass number may correspond to a portion of the azobisisobutyronitrile molecule, for example, the mass of an isobutyl group (-CH(CH3)2) plus a nitrogen atom (N); m / z 54.1: This mass number may correspond to the mass of an isobutyl group (-CH(CH3)2); m / z 41.0: This mass number corresponds to the mass of a methyl group (-CH3) plus a carbon atom (C) in an isobutyl group (-CH(CH3)2).

[0049] To better understand the testing method for azobisisobutyronitrile in photoresist resin of the present invention, the testing method for azobisisobutyronitrile in photoresist resin of the present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0050] The reagents and instruments used in the following examples are all conventional reagents and instruments, which can be purchased from the market, as detailed below:

[0051] 1. Reagents

[0052] Tetrahydrofuran (Fisher brand, HPLC grade, 4L packaging), 2,2-azobisisobutyronitrile (CATO, purity 98.3%, chemical standard).

[0053] 2. Instruments

[0054] Gas chromatography-mass spectrometry (model: 8890-5977, Agilent Technologies, combining an Agilent 8890 gas chromatograph and a 5977 series mass spectrometer detector), pipettes (Eppendorf 10-100uL, 100-1000uL, 0.1-5mL), and electronic balance (Mettler Toledo XSR 304).

[0055] Example 1

[0056] This embodiment provides a test method for azobisisobutyronitrile (AIBN) in photoresist resin, specifically as follows:

[0057] (1) Preparation of standard solutions: Weigh 0.02 g of pure 2,2-azobisisobutyronitrile (AIBN) and dilute to 20 mL with tetrahydrofuran (THF) to prepare a 1000 mg / L AIBN standard stock solution; measure 2 mL of the 1000 mg / L AIBN standard stock solution and dilute to 20 mL with THF to prepare a 100 mg / L AIBN standard solution; use the 100 mg / L AIBN standard solution to serially dilute the standard concentration points to 2 mg / L, 5 mg / L, 15 mg / L, 20 mg / L and 50 mg / L to prepare a series of azobisisobutyronitrile standard solutions.

[0058] (2) Pretreatment of photoresist resin sample: Weigh 0.5g of photoresist resin sample and dissolve it in 5mL of THF by ultrasonication to obtain sample solution. Then take 2mL of sample solution and filter it using a filter membrane with a pore size of 0.45μm to obtain filtrate.

[0059] (3) Preparation of blank control sample: Take 0.5g of THF to replace the photoresist resin sample and process it according to step (2);

[0060] (4) Detection: The filtrate prepared in step (2) and the series of standard solutions prepared in step (1) were quantitatively analyzed by gas chromatography-mass spectrometry and the external standard curve method was used to obtain the content of azobisisobutyronitrile in the filtrate. Then the content of azobisisobutyronitrile in the photoresist resin sample was calculated.

[0061] Specifically, the external standard curve method involves first performing gas chromatography-mass spectrometry (GC-MS) on a series of standard solutions with known concentrations from step (1) to obtain the signals of the standard solutions, plotting a standard curve between signal intensity and concentration, and calculating the regression equation with the concentration of the standard solutions as the abscissa and the signal intensity as the ordinate. Then, after injecting the filtrate, the concentration of azobisisobutyronitrile in the filtrate is calculated based on the signal intensity.

[0062] The testing conditions for gas chromatography-mass spectrometry (GC-MS) are as follows:

[0063] The gas chromatography conditions were as follows: the column was an HP-5ms capillary column with the following specifications: length 30m, inner diameter 0.25mm, and film thickness 0.25μm; the injection port temperature was 280℃, the injection volume was 1μL, the split ratio was 20:1, the column flow rate was 1.00mL / min, and the solvent delay time was 2.3min; the column temperature program was as follows: the initial temperature of the column oven was 50℃ and held for 1min, then the temperature was increased to 320℃ at a rate of 30℃ / min and held for 3min.

[0064] The conditions for the mass spectrometer detector are as follows: the scanning range of the mass spectrometer detector is 29–550 m / z; the scanning mode is simultaneous full scan (SCAN) and selected ion monitoring (SIM) mode; the characteristic ions of AIBN can be selected as 69.1, 54.1, and 41.0.

[0065] Example 2

[0066] 1. Standard working curve and correlation coefficient

[0067] The standard solutions of a series of concentrations prepared in step (1) were analyzed by gas chromatography-mass spectrometry using the method in Example 1. A standard working curve was plotted, and the linear correlation coefficient R was found to be 0.9999, indicating a good linear relationship between the response signal and the concentration.

[0068] 2. Limit of Detection (MDL)

[0069] A low-concentration AIBN standard solution was spiked in THF solvent at a concentration of 2 mg / L. The test method described in Example 1 was used for seven parallel tests. The average value and standard deviation (SD) of the samples were calculated based on the seven test results. The limit of detection (MDL) was calculated using the 3SD method. The results are shown in Table 1 below.

[0070] Table 1. Detection Limit Results

[0071]

[0072] 3. Precision and accuracy

[0073] Low, medium, and high concentrations of AIBN standard solution were added to the THF sample to achieve concentrations of 2 mg / L, 15 mg / L, and 50 mg / L, respectively. Six parallel tests were performed using the method described in Example 1. The relative standard deviation and recovery rate of the six results were calculated, and the results are as follows:

[0074] Table 2. Test results at low concentrations (2 mg / L)

[0075]

[0076] Table 3. Test results at medium concentration (15 mg / L)

[0077]

[0078] Table 4. Test results at high concentrations (50 mg / L)

[0079]

[0080] The data in Tables 2-4 show that the relative standard deviations of multiple parallel tests for low, medium, and high spiking concentrations ranged from 0.85% to 5.87%, indicating high precision of the method. The recoveries of AIBN in THF ranged from 94.8% to 102.3%, indicating good accuracy of the test method.

[0081] Example 3

[0082] Determination of actual samples

[0083] Using the method in Example 1, the content of azobisisobutyronitrile (AIBN) in commercially available photoresist resin samples (low-concentration sample 1 and high-concentration sample 2) was determined. The actual sample test results of low-concentration sample 1 and high-concentration sample 2 were relatively stable. The specific results are shown in Tables 5 and 6.

[0084] Table 5. Test results of low concentration sample 1

[0085]

[0086] Table 6. Test results of high-concentration sample 2

[0087]

[0088] In summary, in this invention, the photoresist resin sample is ultrasonically dissolved in tetrahydrofuran, then filtered through a membrane filter to obtain the filtrate. The filtrate is then separated by gas chromatography to obtain azobisisobutyronitrile (AIBN). The separated components are ionized into ions in a mass spectrometer, and then separated and detected based on the mass-to-charge ratio of the ions. The pretreatment steps for the photoresist resin sample in this invention are simple. After pretreatment, the analyte is fully dissolved in the solvent, reducing interference from other impurities in the sample. Furthermore, the testing method in this invention has high precision and good accuracy, and the test results are relatively stable for both high-concentration and low-concentration actual samples. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for testing azobisisobutyronitrile (AIO) in photoresist resin, characterized in that, The photoresist resin sample was pretreated to obtain a filtrate, and the content of azobisisobutyronitrile in the filtrate was determined by gas chromatography-mass spectrometry. The content of azobisisobutyronitrile in the photoresist resin sample was then calculated.

2. The test method for azobisisobutyronitrile in photoresist resin according to claim 1, characterized in that: The pretreatment includes the following steps: ultrasonically dissolving the photoresist resin sample in tetrahydrofuran to obtain a sample solution, and then taking a certain amount of the sample solution and filtering it using a membrane filter to obtain a filtrate.

3. The test method for azobisisobutyronitrile in photoresist resin according to claim 2, characterized in that: The mass-to-volume ratio of the photoresist resin sample to the tetrahydrofuran is 1:(8-12)(g / mL).

4. The test method for azobisisobutyronitrile in photoresist resin according to claim 2, characterized in that: The pore size of the membrane filter is 0.22μm to 0.45μm.

5. The method for testing azobisisobutyronitrile in photoresist resin according to claim 1, characterized in that: The gas chromatography-mass spectrometry detection method includes the following steps: S1. Preparation of standard solutions: Prepare a series of azobisisobutyronitrile standard solutions of various concentrations; S2. The filtrate and a series of concentrations of azobisisobutyronitrile standard solutions were analyzed by gas chromatography-mass spectrometry, and quantitative analysis was performed by external standard curve method to obtain the content of azobisisobutyronitrile in the filtrate.

6. The test method for azobisisobutyronitrile in photoresist resin according to claim 5, characterized in that: The gas chromatographic column used in step S2 is an HP-5ms capillary column.

7. The test method for azobisisobutyronitrile in photoresist resin according to claim 5, characterized in that: In step S2, the gas chromatograph has an injection port temperature of 260℃~300℃, an injection volume of 1μL, a split ratio of 20:1~50:1, a column flow rate of 1.00~2.00mL / min, and a solvent delay time of 2.3min.

8. The method for testing azobisisobutyronitrile in photoresist resin according to claim 5, characterized in that: In step S2, the gas chromatograph is heated from the initial temperature at a rate of 20℃ / min to 30℃ / min, wherein the initial temperature is 40℃ to 60℃.

9. The method for testing azobisisobutyronitrile in photoresist resin according to claim 5, characterized in that: The mass spectrometry scanning range in step S2 is 29–550 m / z.

10. The method for testing azobisisobutyronitrile in photoresist resin according to claim 5, characterized in that: The mass spectrometry scanning mode described in step S2 is a simultaneous full scan mode and a selected ion monitoring mode.

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