Purification method of electronic-grade diazo naphthoquinone photoinitiator

Abstract

The invention discloses a method for purifying an electronic-grade diazonaphthoquinone photoinitiator, which comprises the following steps of: separating metal ion impurities in a photoinitiator solution in a nanofiltration membrane chamber into a purification chamber by utilizing a transmembrane pressure difference between two sides of a nanofiltration membrane, and then adsorbing through an ion exchange column to realize the purification of the diazonaphthoquinone photoinitiator. And the dosage of a purification solvent is saved, so that the discharge of waste liquid in the purification process is greatly reduced. The process is simple and efficient, the problem that the diazo naphthoquinone type photoinitiator cannot be purified through traditional recrystallization or directly through an ion exchange column and other methods is solved, and the purification effect can reach the electronic grade standard.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic-grade chemical purification, and particularly relates to a method for purifying an electronic-grade naphthoquinone diazonium photoinitiator. Background Art

[0002] Diazonaphthoquinone photoinitiator is the core component of g / i-line photoresist for semiconductors. Its properties determine the key indicators of photoresist, such as sensitivity and resolution. Since the semiconductor manufacturing process has extremely high requirements for the purity of electronic chemicals such as photoresist, especially the content of metal ion impurities, the removal of metal ion impurities is the key to the large-scale purification technology of photoresist photoinitiator.

[0003] Commonly used naphthoquinone diazo photoinitiators are prepared by esterification of 2-diazo-1-naphthoquinone-5-sulfonyl chloride and polyphenol backbone compounds. Since the backbone compound has multiple reaction sites, the naphthoquinone diazo photoinitiator is usually a mixture of multiple substitution products, and the physical properties of different substitution products are similar. Traditional methods such as column chromatography and recrystallization are not suitable for purifying this type of photoinitiator. Secondly, the phenol group on the backbone compound is not completely substituted when synthesizing the photoinitiator. Its solution is acidic, and its hydrogen ions are easily dissociated in the solution, thereby converting the photoinitiator molecule into anionic compounds, resulting in large adsorption differences between photoinitiators with different substitutions on ion exchange resins, and it is impossible to directly use ion exchange columns to remove metal ions from the photoinitiator solution. In industry, the method of ultrapure good solvent dissolution-non-good solvent precipitation and filtration is commonly used to purify this type of compound, but the removal of trace and trace metal ions requires repeated processes many times, the solvent cost consumption is high, and a large amount of organic waste liquid will be generated. In view of the above reasons, the purification technology of diazonaphthoquinone type photoinitiators has always been a difficulty and pain point in the semiconductor key raw materials industry. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a method for purifying an electronic-grade naphthoquinone diazonoquinone photoinitiator. Metal ion impurities in the naphthoquinone diazonoquinone photoinitiator are removed by a nanofiltration membrane and an ion exchange resin column combination device. The target metal ion content in the naphthoquinone diazonoquinone photoinitiator can be purified from the 10-200 ppb level to the 10-50 ppt level under room temperature conditions.

[0005] In order to achieve the above object, the present invention provides a method for purifying an electronic grade naphthoquinone diazonium photoinitiator, comprising the following steps: (1) Preparing a photoinitiator solution: dissolving the photoinitiator in a mixed solvent and filtering to obtain a photoinitiator solution; (2) Construction of nanofiltration purification device: One chamber is separated by two nanofiltration membranes to form a purification chamber-nanofiltration chamber-purification chamber structure; (3) Nanofiltration: The photoinitiator solution is placed in the nanofiltration membrane chamber, and the mixed solvent is placed in the purification chamber for circulating nanofiltration; (4) Ion exchange: perform ion exchange on the mixed solvent in the purification chamber, and circulate nanofiltration and ion exchange; circulate the photoinitiator pipeline in the nanofiltration membrane chamber; (5) collecting the purified photoinitiator solution in the nanofiltration membrane chamber, adding water to crystallize, and drying to obtain a purified photoinitiator; (6) Resin regeneration: Preferably, the concentration of the photoinitiator in step (1) is 25%-40%; and the mixed solvent consists of 80%-95% organic solvent and 5%-20% ultrapure water.

[0006] More preferably, the organic solvent is any one of 1,4-dioxane, N,N-dimethylformamide, methanol, ethanol and dimethyl sulfoxide.

[0007] Preferably, the nanofiltration membrane in step (2) is an inorganic ceramic nanofiltration membrane or a solvent-resistant polymer nanofiltration membrane with a cutoff size of <3 nm.

[0008] Further preferably, the inorganic ceramic nanofiltration membrane is made of a composite of any one or more materials selected from the group consisting of alumina (Al2O3), zirconium dioxide (ZrO2), silicon dioxide (SiO2) and titanium dioxide (TiO2); the solvent-resistant polymer nanofiltration membrane is any one of polyacrylonitrile (PAN), polyamide (PA), polyimide (PI), polyetheretherketone (PEEK), polysulfone (PSf) and polybenzimidazole (PBI).

[0009] Preferably, the circulating nanofiltration flow rate of the nanofiltration membrane chamber in step (3) is 20-40 L / h, and the circulating nanofiltration flow rate of the purification chamber is 10-30 L / h or 30-50 L / h.

[0010] Further preferably, the circulating nanofiltration flow rate of the purification chamber is switched every 30-90 minutes.

[0011] Preferably, the ion exchange in step (4) uses a combined hydrogen type cation exchange resin.

[0012] Further preferably, the combined hydrogen type cation exchange resin is any two or more of AMBERLITE1600, SC670N, SC1600CP, LSC400, LDX604, and ZGCNR80, with a volume ratio of 1:1-4.

[0013] Preferably, in step (5), when the content of target metal ions in the photoinitiator solution in the nanofiltration chamber is ≤50 ppt, discharge and collection are performed.

[0014] Preferably, in step (6), when the target metal ion content in the solution at the outlet of the ion exchange column is ≥45 ppt, the resin is regenerated by repeated elution with electronic grade sulfuric acid.

[0015] The present invention also provides a purification device for electronic-grade naphthoquinone diazide photoinitiators: a first nanofiltration membrane and a second nanofiltration membrane are arranged in a chamber to divide the chamber into three parts, namely a first purification chamber, a nanofiltration membrane chamber and a second purification chamber; one side of the first purification chamber is connected to a first ion exchange column pipeline, the first ion exchange column is connected to a first external interface via a first circulation pump, and the first external interface is connected to the other side of the first purification chamber; one side of the second purification chamber is connected to a second ion exchange column pipeline, the second ion exchange column is connected to a second external interface via a third circulation pump, and the second external interface is connected to the other side of the second purification chamber; one side of the nanofiltration membrane chamber is connected to a second circulation pump pipeline, the second circulation pump is connected to a third external interface pipeline, and the third external interface is connected to the other side of the nanofiltration membrane chamber.

[0016] The beneficial effects of the present invention are: 1. By combining nanofiltration and ion exchange methods to remove metal ion impurities in diazonaphthoquinone photoinitiators, the content of target metal ions was purified from 10-200 ppb level to 10-50 ppt level, thus achieving the purification of diazonaphthoquinone photoinitiators.

[0017] 2. By setting different flow rates through the circulation pump, the photoinitiator solution and the mixed solvent can run at different flow rates in the nanofiltration membrane chamber and the purification chamber respectively. A pressure difference will be formed in the nanofiltration membrane chamber and the purification chamber. Combined with the concentration difference of metal ions inside and outside the membrane, the metal ions in the nanofiltration chamber are separated to the purification chamber, and then adsorbed by the ion exchange resin column to recycle the mixed solvent. When a certain amount of solute molecules accumulate in the inner layer of the nanofiltration membrane, the metal ion penetration effect will decrease. At this time, changing the order of flow rate difference will generate reverse pressure, and the solvent reversely penetrates to dissociate the adsorbed solute molecules, thereby improving the ion penetration effect and thus improving the purification effect.

[0018] 3. The process of the present invention is simple and efficient, which greatly reduces the discharge of purified waste liquid. The electronic grade naphthoquinone diazonium photoinitiator can be obtained without repeated purification, which solves the pain point that the naphthoquinone diazonium photoinitiator cannot be purified by traditional recrystallization or ion exchange resin and other purification methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a schematic structural diagram of a purification device for an electronic-grade naphthoquinone diazide photoinitiator in Example 1, wherein 1 is a first purification chamber, 2 is a nanofiltration membrane chamber, 3 is a second purification chamber, 4 is a first nanofiltration membrane, 5 is a second nanofiltration membrane, 6 is a first ion exchange column, 7 is a second ion exchange column, 8 is a first circulation pump, 9 is a second circulation pump, 10 is a third circulation pump, 11 is a first external interface, 12 is a second external interface, and 13 is a third external interface.

[0020] Figure 2 The graph is a graph showing the change in sodium ion concentration in the nanofiltration membrane chamber at different flow rates in Example 1 and Comparative Examples 1-2.

[0021] Figure 3 Schematic diagrams of the chemical structures of different types of photoinitiators in Examples 1-3 and the general chemical structure formula of naphthoquinone diazide photoinitiators. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be understood as limiting the present invention. The protection scope of the present invention shall be based on the contents recorded in the claims. Any modification or replacement made by those skilled in the art to the technical solution of the present invention without creative work shall fall within the protection scope of the present invention.

[0023] Example 1 Construction of purification device like Figure 1 , constructing a purification device for electronic grade naphthoquinone diazide photoinitiator, setting a first nanofiltration membrane 4 and a second nanofiltration membrane 5 in a chamber to divide the chamber into three parts, namely a first purification chamber 1, a nanofiltration membrane chamber 2, and a second purification chamber 2; One side of the first purification chamber 1 is connected to the first ion exchange column 6 pipeline, the first ion exchange column 6 is connected to the first external interface 11 via the first circulation pump 8, and the first external interface 11 is connected to the other side of the first purification chamber 1; One side of the second purification chamber 3 is connected to the second ion exchange column 7 pipeline, the second ion exchange column 7 is connected to the second external interface 12 via the third circulation pump 10, and the second external interface 12 is connected to the other side of the second purification chamber 3; One side of the nanofiltration membrane chamber 2 is connected to the second circulation pump 9 via a pipeline, the second circulation pump 9 is connected to the third external interface 13 via a pipeline, and the third external interface 13 is connected to the other side of the nanofiltration membrane chamber 2 .

[0024] Example 2 CRM-NF ceramic nanofiltration membrane (CRM inorganic ceramic membrane is a composite material synthesized from high-purity alumina, zirconium oxide, titanium oxide and other materials) was selected, and AMBERLITE1600 and LDX604 were mixed in a mass ratio of 2:1 as ion exchange resin to purify PAC-1 type photoinitiator. The specific steps are as follows: (1) preparing a mixed solvent: mixing 1,4-dioxane and ultrapure water in a mass ratio of 9:1 to obtain a mixed solvent; (2) Preparing a photoinitiator solution: dissolving a PAC-1 photoinitiator in a mixed solvent and filtering the mixture through a 5000-mesh filter to prepare a photoinitiator solution having a mass concentration of 30%; (3) Pumping the photoinitiator solution prepared in step (2) into the nanofiltration membrane chamber 2, and at the same time pumping the mixed solvent into the purification chamber 1 and the purification chamber 2; setting the flow rates of the first circulation pump 8, the second circulation pump 9 and the third circulation pump 10 to 40 L / h, 25 L / h and 10 L / h, respectively, and starting the three circulation pumps to ensure that the purification chamber and the nanofiltration membrane chamber are completely filled with the solution; (4) The flow rate of the circulation pump is adjusted every 60 minutes, that is, the flow rate of the first circulation pump 8, the second circulation pump 9 and the third circulation pump 10 is changed from 40 L / h, 25 L / h and 10 L / h to 10 L / h, 25 L / h and 40 L / h; (5) Sampling the target metal ion content in the photoinitiator was detected every 2 hours from the nanofiltration membrane chamber. When the content was less than 50 ppt, the photoinitiator solution in the nanofiltration membrane chamber was discharged, and excess ultrapure water was added to precipitate the photoinitiator solid, which was then dried at 40°C to obtain the purified PAC-1 type photoinitiator. (6) Detect the target metal ion content at the outlet of the ion exchange column: when the metal ion content is 30 ppt, add new photoinitiator solution for circulation purification. When the metal ion content is greater than 45 ppt, stop the circulation and regenerate the resin by eluting with high-purity sulfuric acid. The regenerated resin is filled into the ion exchange column again for circulation purification.

[0025] Comparative Example 1 The method and steps are the same as those in Example 2, except that the flow rates of the first circulation pump 8, the second circulation pump 9 and the third circulation pump 10 in step (3) are changed to 30 L / h, 20 L / h and 10 h, and the flow rates in step (4) are changed to 10 h, 20 L / h and 30 L / h, respectively, to prepare a purified PAC-1 type photoinitiator.

[0026] Comparative Example 2 The method and steps are the same as those in Example 2, except that the flow rates of the first circulation pump 8, the second circulation pump 9 and the third circulation pump 10 in step (3) are changed to 50 L / h, 30 L / h and 10 h, and the flow rates in step (4) are changed to 10 h, 30 L / h and 50 L / h, respectively, to prepare a purified PAC-1 type photoinitiator.

[0027] Results: The sodium ion concentration of the initial photoinitiator solution was tested, and then samples were taken from the nanofiltration membrane chamber every 10 minutes after the start of the recirculation purification to test the sodium ion concentration. The results are shown in Table 1 and Figure 2 : Table 1 Sodium ion concentration in the nanofiltration membrane chamber every 10 min at different circulation flow rates

[0028] Note: The unit of sodium ion concentration in Table 1 is ppb.

[0029] From Table 1 and Figure 2 It can be seen that compared with Example 2, when the circulation flow rate is 10 / 20 / 30 L / h (Comparative Example 1), the sodium ion concentration decreases at a uniform rate; however, compared with Example 1, the rate of decrease of the sodium ion content under this condition is slower, so the purification efficiency is poor.

[0030] Compared with Example 2, when the circulation flow rate is 10 / 30 / 50 L / h (Comparative Example 2), the sodium ion concentration decreases rapidly in the initial stage, but slows down significantly after 20 minutes, and the purification rate stops suddenly. Through analysis, it is found that compared with Example 1, this flow rate condition leads to too large a transmembrane pressure difference, so that the macromolecules are quickly adsorbed on the surface of the nanofiltration membrane and cannot be desorbed, resulting in a significant decrease in separation efficiency. This condition also does not meet the purification requirements.

[0031] Example 2 The method and steps are the same as those in Example 2, except that the PAC-1 photoinitiator is replaced by a PAC-2 photoinitiator to prepare a purified PAC-2 photoinitiator.

[0032] Example 3 The method and steps are the same as those in Example 2, except that the PAC-1 photoinitiator is replaced by a PAC-3 photoinitiator to prepare a purified PAC-3 photoinitiator.

[0033] Table 2 Purification effect of different types of photoinitiators

[0034] It can be seen from Table 2 that the content of target metal ions can be significantly reduced by purifying different types of photoinitiators using nanofiltration and ion exchange chromatography.

[0035] Example 4 Exploring different solvent combinations The method and steps are the same as those in Example 2, except that the mixed solvent in step (1) is prepared by mixing N,N-dimethylformamide (DMF) and ultrapure water in a mass ratio of 9:1.

[0036] Example 5: Exploring different resin combinations The method and steps are the same as those in Example 2, and SC670N and SC1600CP are mixed in equal proportions as ion exchange resins to perform specific purification on calcium ions.

[0037] Comparative Example 3: Exploring different types of nanofiltration membranes The method and steps are the same as in Example 2, using PAN nanofiltration membrane.

[0038] Comparative Example 4: Investigating the effect of water on metal ion exchange rate The method and steps are the same as those in Example 2, except that the mixed solvent is completely replaced with 1,4-dioxane to prepare a purified PAC-1 type photoinitiator.

[0039] Comparative Example 5: Influence of heterogeneous system on purification effect The method and steps are the same as those in Example 2, except that the mixed solvent is completely replaced with ultrapure water to prepare a heterogeneous system of photoinitiator and water, thereby preparing a purified PAC-1 type photoinitiator.

[0040] Comparative Example 6: Effect of Photoinitiator Solution Concentration on Purification Efficiency The method and steps were the same as those in Example 2, except that the concentration of the photoinitiator solution was changed to 20%, thereby preparing a purified PAC-1 type photoinitiator.

[0041] Comparative Example 7 Investigating the Effect of Photoinitiator Solution Concentration on Purification Efficiency The method and steps were the same as those in Example 2, except that the concentration of the photoinitiator solution was changed to 40%, thereby preparing a purified PAC-1 type photoinitiator.

[0042] Table 3 Comparison of technical ion content before and after purification under different conditions

[0043] By comparing Example 4 with Example 2, when the combination of 1,4-dioxane / water and DMF / water is used, both can achieve good purification effects on PAC-1. However, when the DMF / water system is used, the removal effect on calcium and magnesium ions is weakened. This may be because DMF has a stronger elution ability for these two ions on the purification resin column. Therefore, in actual application, it is necessary to optimize the solvent selection in combination with the purification object.

[0044] By comparing Example 5 with Example 2, after replacing the resin combination, specific purification can be performed on calcium and magnesium ions to reduce their content to the ppt level.

[0045] By comparing Comparative Example 3 with Example 2, after replacing the nanofiltration membrane, the removal performance of metal ions with a larger hydration radius, such as calcium, iron, and aluminum, decreased.

[0046] By comparing Comparative Example 4 with Example 2, when using pure organic solvent, the time required to achieve the same purification effect (iron ion content less than 40 ppt) is significantly extended (from 4 hours to 8 hours), so the water in the mixed solvent can significantly increase the ion exchange rate and improve the purification efficiency.

[0047] By comparing Comparative Example 5 with Example 2, in the case of a heterogeneous system, since a large amount of metal ions are coated on the solid particles and cannot be exchanged, a relatively high metal ion content is still detected in the purified solid particles.

[0048] By comparing Comparative Example 6, Comparative Example 7 and Example 2, when the concentration of the photoinitiator solution is changed, a larger concentration brings a larger concentration difference, which can increase the ion exchange rate, and then the rate at which the surface of the nanofiltration membrane is contaminated also increases. To achieve the same purification effect (iron ion content less than 40ppt), Comparative Example 6 requires 6 hours, and Comparative Example 7 and Example 2 require 4 hours, but considering the problem of membrane regeneration, the concentration setting in Example 2 is preferred.

[0049] Comparative Example 7: No ion exchange column is installed to explore the amount of mixed waste liquid produced (1) preparing a mixed solvent: mixing 1,4-dioxane and ultrapure water in a mass ratio of 9:1 to obtain a mixed solvent; (2) Preparing a photoinitiator solution: dissolving a PAC-1 photoinitiator in a mixed solvent and filtering the mixture through a 5000-mesh filter to prepare a photoinitiator solution having a mass concentration of 30%; (3) The photoinitiator solution prepared in step (2) is pumped into the nanofiltration membrane chamber 2, and the mixed solvent is pumped into the purification chamber 1 and the purification chamber 2 at the same time, and the flow rate of the purification chamber 1 is set to 40 L / h, and the flow rate of the purification chamber 2 is set to 10 L / h; after 60 minutes, the flow rate is switched to prepare a purified PAC-1 type photoinitiator.

[0050] The results show that when the PAC-1 type photoinitiator reaches the electronic grade standard, the amount of the mixed solvent used is 20 times that of Example 2.

[0051] Comparative Example 8: Investigating the Destructive Effect of Direct Ion Exchange Column Purification on Photoinitiators The PAC-1 photoinitiator solution was directly passed into an ion exchange column for purification, wherein the ion exchange column was filled with AMBERLITE1600 and LDX604 resins in a mass ratio of 2:1 (the same as in Example 2); the metal ion content before and after purification was the same as in Example 2, but the ratio of the monosubstituted product to the disubstituted product in the PAC-1 photoinitiator was changed from 2:3 to 1:2, and the performance of the photoinitiator was changed, indicating that the diazonaphthoquinone photoinitiator cannot be directly purified by the ion exchange method.

Claims

1. A method for purifying an electronic grade naphthoquinone diazonium photoinitiator, characterized in that: The following steps are involved: (1) Preparing a photoinitiator solution: dissolving the photoinitiator in a mixed solvent and filtering to obtain a photoinitiator solution; (2) Construction of nanofiltration purification device: One chamber is separated by two nanofiltration membranes to form a purification chamber-nanofiltration chamber-purification chamber structure; (3) Nanofiltration: The photoinitiator solution is placed in the nanofiltration membrane chamber, and the mixed solvent is placed in the purification chamber for circulating nanofiltration; (4) Ion exchange: perform ion exchange on the mixed solvent in the purification chamber, and circulate nanofiltration and ion exchange; circulate the photoinitiator pipeline in the nanofiltration membrane chamber; (5) collecting the purified photoinitiator solution in the nanofiltration membrane chamber, adding water to crystallize, and drying to obtain a purified photoinitiator; (6) Resin regeneration; Step (3) The circulating nanofiltration flow rate of the purification chamber is switched every 30-90 min; In step (5), when the content of target metal ions in the photoinitiator solution in the nanofiltration chamber is ≤50 ppt, discharge and collection are performed.

2. The method for purifying an electronic grade naphthoquinone diazonium photoinitiator according to claim 1, characterized in that: The concentration of the photoinitiator in step (1) is 25%-40%; the mixed solvent is composed of 80%-95% organic solvent and 5%-20% ultrapure water.

3. The method for purifying an electronic grade naphthoquinone diazonium photoinitiator according to claim 2, characterized in that: The organic solvent is any one of 1,4-dioxane, N,N-dimethylformamide, methanol, ethanol and dimethyl sulfoxide.

4. The method for purifying an electronic grade naphthoquinone diazonium photoinitiator according to claim 1, characterized in that: The nanofiltration membrane described in step (2) is an inorganic ceramic nanofiltration membrane or a solvent-resistant polymer nanofiltration membrane with a retention size of <3 nm.

5. The method for purifying an electronic grade naphthoquinone diazide photoinitiator according to claim 1, characterized in that: The circulating nanofiltration flow rate of the nanofiltration membrane chamber in step (3) is 20-40 L / h, and the circulating nanofiltration flow rate of the purification chamber is 10-30 L / h or 30-50 L / h.

6. The method for purifying an electronic grade naphthoquinone diazonium photoinitiator according to claim 1, characterized in that: The ion exchange in step (4) uses a combined hydrogen type cation exchange resin.

7. The method for purifying an electronic grade naphthoquinone diazonium photoinitiator according to claim 6, characterized in that: The combined hydrogen type cation exchange resin is any two or more of AMBERLITE1600, SC670N, SC1600CP, LSC400, LDX604, and ZGCNR80.

8. The method for purifying an electronic grade naphthoquinone diazide photoinitiator according to claim 1, characterized in that: In step (6), when the target metal ion content in the solution at the outlet of the ion exchange column is ≥45 ppt, sulfuric acid is used to regenerate the resin.

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