A method for identifying photoacid-generating agents in photoresists

Abstract

This invention belongs to the field of photoresist and relates to a method for identifying photoacid-generating agents in photoresist. The method includes: sequentially heating, grinding, extracting, and filtering uncured photoresist; then performing LC-MS analysis on the resulting test solution to obtain an LC-MS total ion current chromatogram; obtaining the molecular formula of the positive ion of the photoacid-generating agent from the LC-MS total ion current chromatogram in positive ion mode; obtaining the molecular formula of the negative ion of the photoacid-generating agent from the LC-MS total ion current chromatogram in negative ion mode; and determining the specific molecular formula of the photoacid-generating agent in the photoresist based on the obtained molecular formulas of the positive and negative ions. The method provided by this invention can accurately identify photoacid-generating agents in photoresist.

Description

Technical Field

[0001] This invention belongs to the field of photoresist, and specifically relates to a method for identifying photoacid-generating agents in photoresist. Background Technology

[0002] Photoresist is the most critical material in the photolithography process. The pattern on the photomask is projected onto the photoresist, triggering a photochemical reaction. After baking and development, the photoresist pattern is formed. This pattern acts as a barrier layer, enabling selective etching or ion implantation. Photoresists are designed for specific exposure wavelengths, primarily for 436nm, 365nm, 248nm, and 193nm. Photoresists have evolved through various stages, including cyclic rubber-diazide systems, phenolic resin-diazonaphthoquinone systems, chemically amplified photoresist systems (poly(p-hydroxystyrene) and its derivatives - photoacid generators, polyalicyclic acrylates and their copolymers - photoacid generators), and EUV-compatible photoresists such as molecular glasses and metal oxides.

[0003] The main components of chemically augmented photoresists are polymer resins, photoacid generators, and corresponding additives and solvents. Among them, photoacid generators are photosensitive compounds that produce acid under light, causing unstable groups on the polymer to detach. Photoacid generators can alter the polarity of the polymer, thereby changing its solubility. Photoacid generators are composed of anions and cations, mainly classified into iodide salts and sulfide salts. Sulfide salt photoacid generators include triphenylsulfonium perfluorobutyl sulfonate, triphenylsulfonium trifluoroacetate, triphenylsulfonium maleate, etc.

[0004] CN114414711A discloses a method for identifying onium salt-based photoacid generators in photoresist. This method involves extracting the photoresist to be identified using an extraction solvent to remove precipitates, then performing GC-MS analysis on the resulting test solution to obtain a GC-MS total ion current chromatogram. Characteristic ion fragments are extracted from the GC-MS total ion current chromatogram to determine the onium salt-based photoacid generators contained in the photoresist. This method is implemented using gas chromatography-mass spectrometry (GC-MS) and identifies photoacid generators through characteristic ion fragments in the GC-MS total ion current chromatogram. However, this method can only identify the types of onium salt-based photoacid generators, such as triphenylsulfides and diphenyliodides, but it cannot determine the specific molecular formula of the photoacid generator. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing methods that cannot determine the specific molecular formula of photoacid generators in photoresists, and to provide a method for identifying photoacid generators in photoresists that can accurately determine the specific molecular formula of photoacid generators.

[0006] After in-depth and extensive research, the inventors of this invention discovered that in the identification of photoacid-producing agents, on the one hand, pre-treating the uncured photoresist at 150–250°C for 2–30 minutes is a specific pretreatment method that can perfectly remove interfering peaks affecting the combined detection of chromatography and mass spectrometry without affecting the photoacid-producing agent, essentially retaining only the characteristic peaks of the photoacid-producing agent, thus reducing signal interference and improving identification sensitivity. On the other hand, in the combined detection of chromatography and mass spectrometry, liquid chromatography-mass spectrometry (LC-MS) is selected instead of traditional gas chromatography-mass spectrometry (GC-MS), using ESI source soft ionization, which generates almost no fragment ions, enabling rapid and accurate determination of the specific molecular formula of the photoacid-producing agent. Based on this, this invention was completed.

[0007] Specifically, the present invention provides a method for identifying photoacid-generating agents in photoresist, wherein the method includes the following steps:

[0008] S1. Pretreatment: Heat the uncured photoresist at 150-250℃ for 2-30 minutes, then grind the cured photoresist, and then extract the photoresist powder with an extraction solution and filter it. The resulting filtrate is the test solution.

[0009] S2, LC-MS analysis and detection: The test solution was detected by LC-MS in positive and negative ion modes using a liquid chromatography-mass spectrometry system. During the detection process, the full scan mode was selected to obtain the LC-MS total ion chromatogram.

[0010] S3. Structural Identification: In positive ion mode, identify the strongest chromatographic peaks from the LC-MS total ion chromatogram and generate the corresponding mass spectrum. Perform molecular formula generation on the mass spectrum peaks to determine the possible elemental composition (C, H, O, S, and I) and the ion mode (M). + In the case of a liquid chromatography-mass spectrometry (LC-MS) instrument, the molecular formula is generated using the corresponding software. A matching result of 95% or higher indicates the molecular formula of the positive ion in the photo-induced acid-producing agent. In negative ion mode, a strong chromatographic peak is identified from the LC-MS total ion chromatogram, and the corresponding mass spectrum is generated. The molecular formula is then generated from the mass spectrum peaks. The possible elemental composition is determined to be C, H, O, N, S, and F, and the ion mode is Mn. - In this case, the molecular formula is generated by the software corresponding to the liquid chromatography-mass spectrometry instrument. The molecular formula of the negative ion in the photoacid generator is the one with a matching result of more than 95%. The specific molecular formula of the photoacid generator in the photoresist is determined based on the obtained molecular formulas of the positive and negative ions.

[0011] The present invention has the following beneficial effects:

[0012] First, the heating treatment method used in the pretreatment process of this invention can not only effectively remove interfering factors and improve the accuracy of LC-MS detection, but also protect the chromatographic column from contamination and effectively protect the equipment.

[0013] Secondly, because this invention uses the LC-MS method and employs ESI source soft ionization, it generates very few fragment ions. At the same time, it uses positive and negative ion modes for scanning, which can quickly determine the molecular formulas of positive and negative ions in photoacid generators, especially thionium salts, and deduce the specific structure, thus achieving accurate identification and judgment.

[0014] Third, the present invention uses LC-MS to identify photoacid-producing agents. Due to the high sensitivity and accuracy of LC-MS testing, it achieves the effect of qualitative identification of trace substances. Detailed Implementation

[0015] This invention does not particularly limit the type of photoacid-producing agent to be detected, and is suitable for identifying all existing photoacid-producing agents, especially thioonium salts. Specific examples of thioonium salts include, but are not limited to, at least one of: triphenylsulfonium trifluoromethanesulfonic acid, triphenylsulfonium nonafluorobutanesulfonate, and (4-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonic acid.

[0016] In step S1, the uncured photoresist is heated at 150–250°C for 2–30 minutes, then the resulting cured photoresist is ground. The resulting photoresist powder is then extracted with an extraction solution and filtered. The resulting filtrate is the test solution. The heating conditions include a temperature of 150–250°C, such as 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or any value between them; and a heating time of 2–30 minutes, such as 2 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, or any value between them. The grinding conditions result in a photoresist powder with a particle size D... 50The preferred size is 1 μm to 1 mm. The type of extraction solution is sufficient to extract the photoacid-generating agent from the cured photoresist powder; specific examples include, but are not limited to, acetonitrile and / or methanol. The extraction method is preferably ultrasonic. The extraction temperature is generally room temperature (20–40°C); the extraction time is generally 20–40 min, such as 20 min, 25 min, 30 min, 35 min, 40 min, or any value between them. The pore size of the filter used for filtration is preferably 0.22–0.45 μm. The solute content in the test solution is preferably 0.1–10 mg / L, more preferably 0.5–10 mg / L. In the specific processing, the photoresist powder can be first extracted with the extraction solution, and then further diluted to the required concentration to obtain the test solution.

[0017] In step S2, the test solution is analyzed by LC-MS in both positive and negative ion modes using a liquid chromatography-mass spectrometry (LC-MS) system. A full scan mode is selected during the detection process to obtain the LC-MS total ion chromatogram. The LC-MS detection is performed using ESI source soft ionization. During the LC-MS detection, the mobile phase generally consists of an aqueous phase and an organic phase. The aqueous phase is preferably an aqueous solution of ammonium formate and / or ammonium acetate, and the organic phase is preferably methanol and / or acetonitrile. The preferred MS analysis conditions include a gas temperature of 250–350°C, a sheath gas temperature of 250–380°C, and a capillary voltage of 2000–4000 V.

[0018] In step S3, information on the positive and negative ions in the photoacid-producing agent is obtained through LC-MS total ion chromatogram, thereby deducing the molecular formula of the photoacid-producing agent. Specifically, in positive ion mode, a strong chromatographic peak is found from the LC-MS total ion chromatogram, and the corresponding mass spectrum is generated. The molecular formula is then generated from the mass spectrum peaks, determining the possible elemental composition as C, H, O, S, and I, and the ion mode as M. + In this case, the corresponding molecular formula is generated using the software of the liquid chromatography-mass spectrometry (LC-MS) instrument. Multiple molecular formulas may be obtained; the one with a matching rate of over 95% (automatically matched by the software) is the molecular formula of the positive ion in the photoacid-producing agent. In negative ion mode, a strong chromatographic peak is found from the LC-MS total ion chromatogram, and the corresponding mass spectrum is generated. The molecular formula is then generated from the mass spectrum peaks. The elemental composition may be C, H, O, N, S, and F, and the ion mode is Mn. -In this case, the corresponding molecular formula is generated using the software of the liquid chromatography-mass spectrometry (LC-MS) instrument. Multiple molecular formulas may be obtained; the one with a matching result of over 95% is the molecular formula of the negative ion in the photoacid-generating agent. The specific molecular formula of the photoacid-generating agent in the photoresist is determined based on the obtained molecular formulas of the positive and negative ions.

[0019] Furthermore, the accuracy of the identification method of this invention can be verified by the following method: extracting positive and negative ion chromatograms with matching results of more than 95% from the total ion chromatogram of LC-MS. When the corresponding characteristic ion can be extracted, it indicates that the photoacid-producing agent does indeed contain the positive and negative ions. For example, the most commonly used thionium salt photoacid-producing agents are triphenylsulfonium trifluoromethanesulfonic acid, triphenylsulfonium nonafluorobutanesulfonate, and (4-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonic acid. Among them, the positive ions include triphenylsulfonium (m / z of mass-to-charge ratio of 263.0889) and (4-tert-butylphenyl)diphenylsulfonium (m / z of mass-to-charge ratio of 319.1515), and the negative ions include trifluoromethanesulfonate (m / z of mass-to-charge ratio of 148.9528) and nonafluorobutanesulfonate (m / z of mass-to-charge ratio of 298.9434). When the photoacid-producing agent identified by the method provided in this invention is triphenylsulfonium trifluoromethanesulfonic acid, its corresponding positive ion is triphenylsulfonium (m / z = 263.0889) and its negative ion is trifluoromethanesulfonate (m / z = 148.9528). In this case, the characteristic ion chromatograms with m / z = 263.0889 and 148.9528 are extracted from the LC-MS total ion chromatogram. If these two characteristic ions with m / z = 148.9528 can be extracted, it indicates that the photoacid-producing agent does indeed contain triphenylsulfonium and trifluoromethanesulfonate, meaning the photoacid-producing agent is indeed triphenylsulfonium trifluoromethanesulfonic acid. This demonstrates that the method provided in this invention is accurate and reliable. Similarly, the same method can be used to verify the accuracy of the identification results for other photoacid-producing agents.

[0020] The present invention will be described in detail below through embodiments.

[0021] In the following examples and comparative examples, the liquid chromatography-mass spectrometry system used was purchased from Agilent Technologies, model 6545Q-TOF LC / MS.

[0022] Example 1: Identification and analysis of known sulfonium salt photoacid-producing agents

[0023] The following are the specific names and structures of three sulfonium salt photoacid-producing agents.

[0024] Triphenylsulfonium trifluoromethanesulfonic acid (PAG01):

[0025] Triphenylsulfonium nonafluorobutane sulfonate (PAGO2):

[0026] (4-tert-Butylphenyl)diphenylsulfonium trifluoromethanesulfonic acid (PAGO3):

[0027] Add 5 mg of PAG01, PAG02 and PAG03 to three 100 mL volumetric flasks respectively, and add acetonitrile to each volumetric flask and make up to 100 mL and shake well. Then dilute each flask 100 times with acetonitrile to obtain three sample solutions to be tested, which are denoted as LPAG01, LPAG02 and LPAG03 respectively.

[0028] Three sample solutions were analyzed using liquid chromatography-mass spectrometry (LC-MS), and total ion chromatograms (TIC chromatograms) were acquired in both positive and negative ion scanning modes. The LC-MS analysis conditions for known sulfonium salt photoacid-generating agents are shown in Table 1.

[0029] Table 1

[0030]

[0031] Note: In Table 1, during the gradient elution process, the proportion of mobile phase A decreases slowly and linearly from 90% to 0 from 0 to 5 min, and the proportion of mobile phase A is 0 and the proportion of mobile phase B is 100% from 5 to 8 min, and the same applies below.

[0032] Results analysis:

[0033] In PAG01, the TIC chromatogram in positive ion mode shows a distinct chromatographic peak between 3.2 and 3.4 min, generating the corresponding mass spectrum. The mass spectrum shows a strong signal at a mass-to-charge ratio of 263.0891, indicating a possible elemental composition of C, H, O, S, and I, and an ion mode of M. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 18 H 15 S is most likely a triphenylsulfide cation. The TIC chromatogram in negative ion mode shows a distinct chromatographic peak between 0.6 and 0.8 min, generating the corresponding mass spectrum. The mass spectrum shows a strong signal at a mass-to-charge ratio of 148.9527, suggesting an elemental composition of C, H, O, N, S, and F, and an ion mode of M. - In this case, by performing operations to generate its molecular formula, we can see that the corresponding molecular formula is CF3O3S, which is very likely trifluoromethanesulfonate. From the positive and negative ion molecular formulas obtained above, we can deduce that the molecular formula of PAG01 is C19 H 15 F3O3S2, thus confirming that PAG01 is triphenylsulfonium trifluoromethanesulfonic acid.

[0034] In PAG02, the TIC chromatogram in positive ion mode shows a distinct chromatographic peak between 3.2 and 3.4 min, generating the corresponding mass spectrum. The mass spectrum shows a strong signal at a mass-to-charge ratio of 263.0890, indicating a possible elemental composition of C, H, O, S, and I, and an ion mode of M. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 18 H 15 S is most likely a triphenylsulfide cation. The TIC chromatogram in negative ion mode shows a distinct peak between 3.6 and 3.8 min, generating the corresponding mass spectrum. The mass spectrum shows a strong signal at a mass-to-charge ratio of 298.9437, suggesting a possible elemental composition of C, H, O, N, S, and F, and an ion mode of M. - In this case, by performing operations to generate its molecular formula, we can see that the corresponding molecular formula is C4F9O3S, which is very likely nonafluorobutane sulfonate. From the positive and negative ion molecular formulas obtained above, we can deduce that the molecular formula of PAG02 is C 22 H 15 F9O3S2, thus confirming that PAG02 is triphenylsulfonium nonafluorobutane sulfonic acid.

[0035] In PAG03, the TIC chromatogram in positive ion mode shows a distinct chromatographic peak between 4.5 and 4.7 min, generating the corresponding mass spectrum. The mass spectrum shows a strong signal at a mass-to-charge ratio of 319.1517, indicating a possible elemental composition of C, H, O, S, and I, and an ion mode of M. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 22 H 23 S is most likely a (4-tert-butylphenyl)diphenylsulfonium cation. The TIC chromatogram in negative ion mode shows a distinct chromatographic peak between 0.69 and 0.83 min. The corresponding mass spectrum for this peak shows a strong signal at a mass-to-charge ratio of 148.9527. This suggests an elemental composition of C, H, O, N, S, and F, and an ion mode of M. -In this case, by performing operations to generate its molecular formula, we can see that the corresponding molecular formula is CF3O3S, which is very likely trifluoromethanesulfonate. From the positive and negative ion molecular formulas obtained above, we can deduce that the molecular formula of PAG03 is C 23 H 23 F3O3S2, thus confirming that PAG03 is (4-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonic acid.

[0036] Example 2: Identification and Analysis of Known Photoresists

[0037] The basic formulation of the photoresist is known to be acrylic resin (10g), sulfonium salt photoacid generator PAG01 (0.5g), triethylamine (0.1g), and propylene glycol monomethyl ether acetate (90g).

[0038] The known preparation method for photoresist is as follows: accurately weigh each material on a balance and place them in a 100mL clean bottle, then shake on a shaker for 1 hour to mix thoroughly. Note that each step must be performed in the yellow light region.

[0039] S1. Pretreatment: Take 10 mL of photoresist in a petri dish, then heat at 180 °C for 15 min, and then grind to a particle size D. 50 To obtain a 10μm solution, the photoresist powder obtained after grinding was added to 20mL of acetonitrile and ultrasonically extracted for 30min. Then, it was diluted 2000 times with acetonitrile, and the clear liquid was drawn up with a syringe and filtered through a 0.45μm filter membrane to obtain the test solution.

[0040] S2. LC-MS Analysis and Detection: The test solution (1 mL) was detected by liquid chromatography-mass spectrometry (LC-MS) in both positive and negative ion modes. Full scan mode was selected during the detection process to obtain the LC-MS total ion chromatogram. The LC-MS analysis and detection conditions for the known photoresist are shown in Table 2.

[0041] Table 2

[0042]

[0043] S3. Identification of photoacid-producing agents:

[0044] The TIC chromatogram of the known photoresist in positive ion mode shows a distinct chromatographic peak between 3.2 and 3.4 min. The corresponding mass spectrum shows a strong signal at a mass-to-charge ratio of 263.0890, indicating a possible elemental composition of C, H, O, S, and I, and an M ion mode. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 18 H 15S is most likely a triphenylsulfide cation. From the TIC chromatogram of the known photoresist in negative ion mode, a distinct chromatographic peak appears within 0.6–0.8 min. The corresponding mass spectrum shows a strong signal at a mass-to-charge ratio of 148.9527, indicating a possible elemental composition of C, H, O, N, S, and F, and an ion mode of M. - In this case, the molecular formula was generated, revealing that the corresponding molecular formula is CF3O3S, which is very likely trifluoromethanesulfonate. Therefore, it can be determined that the photoresist contains triphenylsulfonate, i.e., PAG01. The identification result is consistent with the formulation, indicating that the identification method of this invention is accurate and feasible.

[0045] Example 3: Identification and Analysis of Known Photoresists

[0046] The basic formulation of the photoresist is known to be acrylic resin (10g), sulfonium salt photoacid generator PAG02 (0.5g), triethylamine (0.1g), and propylene glycol monomethyl ether acetate (90g).

[0047] The known preparation method for photoresist is as follows: accurately weigh each material on a balance and place them in a 100mL clean bottle, then shake on a shaker for 1 hour to mix thoroughly. Note that each step must be performed in the yellow light region.

[0048] S1. Pretreatment: Take 10 mL of photoresist in a petri dish, then heat at 220 °C for 10 min, and then grind to a particle size D. 50 To obtain a photoresist with a thickness of 500 μm, the photoresist obtained after grinding was added to 20 mL of methanol and ultrasonically extracted for 30 min. Then, it was diluted 2000 times with methanol, and the clear liquid was drawn up with a syringe and filtered through a 0.45 μm filter membrane to obtain the test clear liquid.

[0049] S2. LC-MS Analysis and Detection: The test solution (1 mL) was detected by liquid chromatography-mass spectrometry (LC-MS) in both positive and negative ion modes. Full scan mode was selected during the detection process to obtain the LC-MS total ion chromatogram. The LC-MS analysis and detection conditions for known photoresists are shown in Table 3.

[0050] Table 3

[0051]

[0052]

[0053] S3. Identification of photoacid-producing agents:

[0054] The TIC chromatogram of the known photoresist in positive ion mode shows a distinct chromatographic peak between 3.3 and 3.4 min. The corresponding mass spectrum shows a strong signal at a mass-to-charge ratio of 263.0890, indicating a possible elemental composition of C, H, O, S, and I, and an M ion mode. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 18 H 15 S is most likely a triphenylsulfide cation. From the TIC chromatogram of the known photoresist in negative ion mode, a distinct chromatographic peak appears between 3.65 and 3.75 min. The corresponding mass spectrum shows a strong signal with a mass-to-charge ratio of 298.9436, indicating a possible elemental composition of C, H, O, N, S, and F, and an ion mode of M. - In this case, the molecular formula was generated, revealing that the corresponding molecular formula is C4F9O3S, which is very likely nonafluorobutane sulfonate. Therefore, it can be confirmed that the photoresist contains triphenylsulfonate nonafluorobutane sulfonate, i.e., PAG02. The identification result is consistent with the formulation, indicating that the identification method of this invention is accurate and feasible.

[0055] Example 4: Identification and Analysis of Known Photoresists

[0056] The basic formulation of the photoresist is known to be acrylic resin (10g), sulfonium salt photoacid generator PAG03 (0.5g), and propylene glycol monomethyl ether acetate (90g).

[0057] The known preparation method for photoresist is as follows: accurately weigh each material on a balance and place them in a 100mL clean bottle, then shake on a shaker for 1 hour to mix thoroughly. Note that each step must be performed in the yellow light region.

[0058] S1. Pretreatment: Take 10 mL of photoresist in a petri dish, expose it at a wavelength of 193 nm for 5 min, then heat it at 240 °C for 5 min, and then grind it to a particle size D. 50 To obtain a photoresist with a thickness of 500 μm, the photoresist obtained after grinding was added to 20 mL of acetonitrile and ultrasonically extracted for 30 min. Then, it was diluted 1000 times with acetonitrile, and the clear liquid was drawn up with a syringe and filtered through a 0.45 μm filter membrane to obtain the test clear liquid.

[0059] S2. LC-MS Analysis and Detection: The test solution (1 mL) was detected by liquid chromatography-mass spectrometry (LC-MS) in both positive and negative ion modes. Full scan mode was selected during the detection process to obtain the LC-MS total ion chromatogram. The LC-MS analysis and detection conditions for the known photoresist are shown in Table 4.

[0060] Table 4

[0061]

[0062] S3. Identification of photoacid-producing agents:

[0063] From the TIC spectrum of the known photoresist in positive ion mode, a distinct chromatographic peak appears between 4.5 and 4.7 min. The corresponding mass spectrum shows a strong signal at a mass-to-charge ratio of 319.1517, indicating a possible elemental composition of C, H, O, S, and I, and an ion mode of M. + In this case, by performing the operation to generate its molecular formula, it can be seen that the corresponding molecular formula is C. 22 H 23 S is most likely a (4-tert-butylphenyl)diphenylsulfonium cation. From the TIC chromatogram of the known photoresist in negative ion mode, a distinct chromatographic peak appears within the range of 0.66–0.83 min. The corresponding mass spectrum shows a strong signal with a mass-to-charge ratio of 148.9527, indicating a possible elemental composition of C, H, O, N, S, and F, and an ion mode of M. - In this case, the molecular formula was generated, revealing that the corresponding molecular formula is CF3O3S, which is very likely trifluoromethanesulfonate. Therefore, it can be determined that the photoresist contains (4-tert-butylphenyl)diphenylsulfonate trifluoromethanesulfonate, i.e., PAG03. The identification result is consistent with the formulation, indicating that the identification method of this invention is accurate and feasible.

[0064] Comparative Example 1: Reference Qualification Analysis of Known Photoresists

[0065] The photoresist was identified and analyzed according to the method in Example 3, except that the steps of heating and grinding the photoresist were not included. Instead, the photoresist was directly dissolved in acetonitrile and subjected to ultrasonic extraction. The specific steps are as follows:

[0066] S1. Pretreatment: Add 10 mL of photoresist to 20 mL of methanol, ultrasonically extract for 30 min, then dilute with methanol 2000 times, draw up the clear liquid with a syringe and filter it through a 0.45 μm filter membrane to obtain the clear liquid to be tested.

[0067] S2, LC-MS analysis and detection: The specific operation and conditions are the same as in Example 3.

[0068] S3. Identification of photo-induced acid-producing agents: The TIC chromatogram in positive ion detection mode shows a significant broadening and weakening of the triphenylsulfonium peak at 3.6 min, possibly due to suppression by other ions. Furthermore, strong interference peaks appeared at 2.4 min and 6–7 min, possibly caused by the solvent or resin. This can significantly interfere with mass spectrometry data analysis, leading to inaccurate identification results.

[0069] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for identifying photoacid-generating agents in photoresist, wherein the photoacid-generating agent to be identified is a thionium salt-based photoacid-generating agent, characterized in that, Includes the following steps: S1. Pretreatment: The uncured photoresist is heated at 150~250℃ for 2~30min, and then the cured photoresist is ground. After that, the photoresist powder is extracted with an extraction solution and filtered. The filtrate is the test solution. The extraction solution is acetonitrile and / or methanol. S2, LC-MS analysis and detection: The test solution was detected by LC-MS in positive and negative ion modes using a liquid chromatography-mass spectrometry system; During the LC-MS detection process, the aqueous phase of the mobile phase for LC analysis is an aqueous solution of ammonium formate and / or ammonium acetate, and the organic phase is methanol; a full scan mode is selected during the detection process to obtain the LC-MS total ion chromatogram. S3. Structural Identification: In positive ion mode, identify the strongest chromatographic peaks from the LC-MS total ion chromatogram and generate the corresponding mass spectrum. Perform molecular formula generation on the mass spectrum peaks to determine the possible elemental composition (C, H, O, S, and I) and the ion mode (M). + In the case of a liquid chromatography-mass spectrometry (LC-MS) instrument, the molecular formula is generated using the corresponding software. A matching result of 95% or higher indicates the molecular formula of the positive ion in the photo-induced acid-producing agent. In negative ion mode, a strong chromatographic peak is identified from the LC-MS total ion chromatogram, and the corresponding mass spectrum is generated. The molecular formula is then generated from the mass spectrum peaks. The possible elemental composition is determined to be C, H, O, N, S, and F, and the ion mode is Mn. - In this case, the molecular formula is generated by the software corresponding to the liquid chromatography-mass spectrometry instrument. The molecular formula of the negative ion in the photoacid generator is the one with a matching result of more than 95%. The specific molecular formula of the photoacid generator in the photoresist is determined based on the obtained molecular formulas of the positive and negative ions.

2. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, In step S1, the grinding conditions result in a photoresist powder with a particle size D. 50 It ranges from 1μm to 1mm.

3. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, In step S1, the extraction method is ultrasonic; the extraction temperature is room temperature and the extraction time is 20~40 min.

4. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, In step S1, the filter used for filtration has a pore size of 0.22~0.45μm.

5. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, In step S1, the solute content in the test solution is 0.5~10 mg / L.

6. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, In step S2, the conditions for MS analysis and detection during the LC-MS detection process include a drying gas temperature of 250~350℃, a sheath gas temperature of 250~380℃, and a capillary voltage of 2000~4000V.

7. The method for identifying photoacid-generating agents in photoresist according to claim 1, characterized in that, The thioonium salt photoacid generator is selected from at least one of triphenylsulfonium trifluoromethanesulfonic acid, triphenylsulfonium nonafluorobutanesulfonic acid, and (4-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonic acid.

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