Method for removing metal impurities in electronic-grade solvent for photoresist
By complexing the synthetic terminal amino hyperbranched polymer NH2-HBP with alcohol solution, the efficiency and cost problems of metal impurities removal in electronic grade solvents for photoresist are solved, and the efficient and low-consumable metal impurities removal effect is achieved, which is suitable for industrial production.
Patent Information
- Application Number
- CN202510689298.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-08-29
AI Technical Summary
The prior art is difficult to efficiently and at low cost to remove metal impurities in electronic grade solvents for photoresist, and traditional methods have problems such as limited selectivity or introduction of secondary contamination.
N,N-methylenebisacrylamide and diethylenetriamine were used to synthesize the terminal amino hyperbranched polymer NH2-HBP, which was used to complex with metal impurities in the alcohol solution, and then evaporate the solvent to obtain an electronic grade alcohol solvent.
It achieves efficient removal of metal impurities, reduces the metal ion content to less than 10 ppb, and is suitable for large-scale industrial applications, reducing purification costs and three waste output.
Smart Images
Figure BDA0005421473710000031 
Figure BDA0005421473710000041 
Figure BDA0005421473710000042
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of materials, and in particular relates to a method for removing metal impurities in an electronic-grade solvent for photoresist. Background Art
[0002] Photoresist, also known as photoresist, refers to a thin film of etching-resistant material whose solubility changes upon exposure to ultraviolet light, electron beams, ion beams, X-rays, or other radiation. In semiconductor manufacturing, photoresist is a core material for pattern transfer, and its performance directly determines chip processing precision and yield. Electronic-grade solvents, as key components of photoresist, must meet extremely high purity requirements, particularly controlling the content of metal impurities (such as sodium, potassium, iron, and copper) to levels of ppb (parts per billion) or even ppt (parts per trillion). The presence of metal impurities can cause uneven photoresist coating and development defects, and can migrate to the silicon wafer surface during subsequent high-temperature processing, leading to reliability risks such as increased device leakage current and gate oxide breakdown. As integrated circuit process nodes advance toward 3nm and below, purity requirements for electronic-grade solvents are becoming increasingly stringent. Traditional purification processes face bottlenecks in removing trace metal impurities, including inefficiency, high costs, and secondary contamination. There is an urgent need to develop more efficient, stable, and industrially scalable metal impurity removal methods.
[0003] Current technologies for removing metal impurities from electronic-grade solvents primarily rely on traditional processes such as ion exchange resins and chemical complexation. However, ion exchange resins have limited selectivity for specific metal ions, and the regeneration process can easily introduce new contaminants. Chemical complexation requires the addition of large amounts of complexing agents, which can leave residual organic matter and affect the electrochemical properties of the solvent. Furthermore, existing methods struggle to simultaneously achieve deep removal of multiple metal impurities, and the process is complex and energy-intensive, limiting their application in the large-scale production of high-end electronic chemicals. Therefore, developing a new, efficient, low-cost, and universally applicable metal impurity removal technology is crucial for improving photoresist performance and ensuring the yield of advanced process chips. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for removing metal impurities in electronic-grade solvents for photoresists. The method has a simple process and produces less three wastes. The purified electronic-grade alcohol solvent can be used for photoresist compounding and is suitable for large-scale industrial applications.
[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:
[0006] A method for removing metal impurities from an electronic-grade solvent for photoresist comprises the following steps:
[0007] 1) Synthesizing amino-terminated hyperbranched polymer NH2-HBP using N,N-methylenebisacrylamide and diethylenetriamine as raw materials;
[0008] 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the alcohol solution and stirring to remove metal impurities in the complexing solvent;
[0009] 3) After the stirring is completed, the solvent is evaporated to obtain an electronic grade alcohol solvent.
[0010] Furthermore, in the step 1), the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5.
[0011] Furthermore, in the step 1), the synthesis temperature is 50-100°C.
[0012] Furthermore, in the step 1), the synthesis time is 5-24 hours.
[0013] Furthermore, in step 2), the alcohol solution is selected from one or more of methanol, ethanol, isopropanol, and ethylene glycol.
[0014] Furthermore, in the step 2), the amount of the amino-terminated hyperbranched polymer NH2-HBP added to the alcohol solvent is 0.01%-0.1%.
[0015] Furthermore, in the step 2), the reaction temperature of adding the amino-terminated hyperbranched polymer NH2-HBP to the alcohol solvent is 20-50°C.
[0016] Furthermore, in the step 2), the reaction time of adding the amino-terminated hyperbranched polymer NH2-HBP to the alcohol solvent is 1-10 hours.
[0017] The content of each metal ion in the purified electronic grade solvent is less than 10 ppb.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] (1) The amino-terminated hyperbranched polymer prepared by the present invention has a simple synthesis process, low raw material cost, and can be applied on an industrial scale.
[0020] (2) The amino-terminated hyperbranched polymer prepared by the present invention has a strong metal ion complexing ability and can effectively remove metal impurities in alcohol solvents. The purified electronic-grade alcohol solvents can be used for photoresist compounding.
[0021] (3) The amount of amino-terminated hyperbranched polymer prepared by the present invention is small, the output of three wastes is small, and the comprehensive cost of electronic grade solvent purification is lower than that of traditional processes. DETAILED DESCRIPTION
[0022] The present invention will be further illustrated below with reference to specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0023] The methanol, ethanol, isopropanol, and ethylene glycol used in the following examples were all purchased from industrial-grade bulk commodities with a purity of ≥99%.
[0024] Example 1
[0025] A method for removing metal impurities from an electronic-grade solvent for photoresist comprises the following steps:
[0026] 1) Using a reaction kettle, first add N,N-methylenebisacrylamide, then add the prepared 5 wt% diethylenetriamine aqueous solution dropwise to the N,N-methylenebisacrylamide (the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5), stir until completely dissolved, increase the temperature to 50°C, react for 24 hours, and after separation, obtain a light yellow liquid as the amino-terminated hyperbranched polymer NH2-HBP.
[0027] 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the ethanol solution, wherein the amount of NH2-HBP added is 0.01% of the mass of the ethanol solution, and stirring at 50° C. for 1 h.
[0028] 3) After the stirring is completed, the solvent is evaporated to obtain an electronic grade alcohol solvent.
[0029] 10 mL of electronic-grade solvent and 1% (volume percentage) electronic-grade nitric acid were added to a conical flask for acidification, and the sample was directly injected after shaking. Under nitrogen protection, the content of each metal ion in the electronic-grade solvent before and after adsorption was detected by ICP-MS. The test results are shown in Table 1.
[0030] Table 1 Metal ion concentrations in electronic grade solvents before and after purification
[0031]
[0032]
[0033] As can be seen from Table 1, before the adsorption treatment with the amino-terminated hyperbranched polymer, the Mg content was 1456.6 ppb, and the Li, Na, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pd, and Sn elements were all much higher than 20 ppb. After the adsorption treatment with the amino-terminated hyperbranched polymer, the contents of most metal ions were less than 10 ppb, especially the Mg content decreased from 1456.6 ppb to 32.0 ppb, and the contents of the metal ions Na, Al, and Ca were reduced to 32.7 ppb, 23.1 ppb, and 18.4 ppb, respectively.
[0034] Example 2
[0035] A method for removing metal impurities from an electronic-grade solvent for photoresist comprises the following steps:
[0036] 1) Using a reaction kettle, first add N,N-methylenebisacrylamide, then add the prepared 5 wt% diethylenetriamine aqueous solution dropwise to the N,N-methylenebisacrylamide (the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5), stir until completely dissolved, increase the temperature to 100°C and react for 5 hours. After separation, a light yellow liquid is obtained, which is the amino-terminated hyperbranched polymer NH2-HBP.
[0037] 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the ethanol solution, wherein the amount of NH2-HBP added is 0.1% of the mass of the ethanol solution, and stirring at 20° C. for 10 h.
[0038] 3) After stirring, the solvent is evaporated to obtain an electronic grade ethanol solvent.
[0039] The method for determining metal impurities was the same as in Example 1. The test results are shown in Table 2.
[0040] Table 2 Metal ion concentrations in electronic grade solvents before and after purification
[0041]
[0042]
[0043] As can be seen from Table 2, before the adsorption treatment with the amino-terminated hyperbranched polymer, the Mg content was 1456.6 ppb, and the Li, Na, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pd, and Sn elements were all much higher than 20 ppb. After the adsorption treatment with the amino-terminated hyperbranched polymer, the contents of most metal ions were less than 10 ppb, especially the Mg content decreased from 1456.6 ppb to 27.5 ppb, and the contents of the metal ions Na, Al, and Ca decreased to 17.6 ppb, 18.4 ppb, and 20.4 ppb, respectively.
[0044] Example 3
[0045] 1) Using a reactor, first add N,N-methylenebisacrylamide, then dropwise add the prepared 5 wt% diethylenetriamine aqueous solution into the N,N-methylenebisacrylamide (the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5), stir until completely dissolved, raise the temperature to 80°C, react for 12 hours, and after separation, obtain a light yellow liquid as the amino-terminated hyperbranched polymer NH2-HBP.
[0046] 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the ethanol solution, wherein the amount of NH2-HBP added is 0.05% of the mass of the ethanol solution, and stirring at 40° C. for 8 h.
[0047] 3) After stirring, the solvent is evaporated to obtain an electronic grade ethanol solvent.
[0048] The method for determining metal impurities was the same as in Example 1. The test results are shown in Table 3.
[0049] Table 3 Metal ion concentrations in electronic grade solvents before and after purification
[0050]
[0051]
[0052] As can be seen from Table 3, before the adsorption treatment with the amino-terminated hyperbranched polymer, the Mg content was 1456.6 ppb, and the Li, Na, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pd, and Sn elements were all much higher than 20 ppb. After the adsorption treatment with the amino-terminated hyperbranched polymer, the contents of most metal ions were less than 10 ppb, especially the Mg content was reduced from 1456.6 ppb to 5.5 ppb, and the contents of the metal ions Na, Al, and Ca were reduced to 7.6 ppb, 1.4 ppb, and 1.0 ppb, respectively.
[0053] Example 4
[0054] 1) Using a reactor, first add N,N-methylenebisacrylamide, then dropwise add the prepared 5 wt% diethylenetriamine aqueous solution into the N,N-methylenebisacrylamide (the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5), stir until completely dissolved, raise the temperature to 80°C, react for 12 hours, and after separation, obtain a light yellow liquid as the amino-terminated hyperbranched polymer NH2-HBP.
[0055] 2) The amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) was added to the methanol solution, with the amount of NH2-HBP added being 0.05% of the mass of the ethanol solution, and stirred at 30° C. for 10 h.
[0056] 3) After the stirring is completed, the solvent is evaporated to obtain electronic grade methanol solvent.
[0057] The method for determining metal impurities was the same as in Example 1. The test results are shown in Table 4.
[0058] Table 4 Metal ion concentrations in electronic grade solvents before and after purification
[0059]
[0060]
[0061] As can be seen from Table 4, before the adsorption treatment with the amino-terminated hyperbranched polymer, the Mg content was 1456.6 ppb, and the Li, Na, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pd, and Sn elements were all much higher than 20 ppb. After the adsorption treatment with the amino-terminated hyperbranched polymer, the contents of most metal ions were less than 10 ppb, especially the Mg content decreased from 1456.6 ppb to 17.6 ppb, and the contents of the metal ions Na, Al, and Ca were reduced to 28.4 ppb, 9.6 ppb, and 8.9 ppb, respectively.
[0062] Example 5
[0063] 1) Using a reactor, first add N,N-methylenebisacrylamide, then dropwise add the prepared 5 wt% diethylenetriamine aqueous solution into the N,N-methylenebisacrylamide (the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.5), stir until completely dissolved, raise the temperature to 80°C, react for 12 hours, and after separation, obtain a light yellow liquid as the amino-terminated hyperbranched polymer NH2-HBP.
[0064] 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the isopropanol solution, wherein the amount of NH2-HBP added is 0.05% of the mass of the ethanol solution, and stirring at 30° C. for 10 h.
[0065] 3) After the stirring is completed, the solvent is evaporated to obtain electronic grade isopropyl alcohol solvent.
[0066] The method for determining metal impurities was the same as in Example 1. The test results are shown in Table 5.
[0067] Table 5 Metal ion concentrations in electronic grade solvents before and after purification
[0068]
[0069]
[0070] As can be seen from Table 5, before the adsorption treatment with the amino-terminated hyperbranched polymer, the Mg content was 1456.6 ppb, and the Li, Na, Al, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pd, and Sn elements were all much higher than 20 ppb. After the adsorption treatment with the amino-terminated hyperbranched polymer, the contents of most metal ions were less than 10 ppb, especially the Mg content was reduced from 1456.6 ppb to 4.2 ppb, and the contents of the metal ions Na, Al, and Ca were reduced to 4.5 ppb, 3.6 ppb, and 2.3 ppb, respectively.
[0071] Comparative Example 1
[0072] The isopropanol solution was directly distilled without using the amino-terminated hyperbranched polymer NH2-HBP. The metal impurities were determined using the same method as in Example 1. The test results are shown in Table 6.
[0073] Table 6 Metal ion concentrations in electronic grade solvents before and after distillation purification
[0074]
[0075]
[0076] As shown in Table 6, when only the distillation process is used for adsorption, the purification effect of most metal ions cannot achieve the same purification effect as that of the metal ion purification system using the amino-terminated hyperbranched polymer.
[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A method for removing metal impurities from an electronic-grade solvent for photoresist, characterized in that: The following steps are involved: 1) Synthesizing amino-terminated hyperbranched polymer NH2-HBP using N,N-methylenebisacrylamide and diethylenetriamine as raw materials; 2) adding the amino-terminated hyperbranched polymer NH2-HBP obtained in step 1) to the alcohol solution and stirring to remove metal impurities in the complexing solvent; 3) After the stirring is completed, the solvent is evaporated to obtain an electronic grade alcohol solvent.
2. The method for removing metal impurities from an electronic-grade solvent for photoresist according to claim 1, wherein: In the step 1), the molar ratio of N,N-methylenebisacrylamide to diethylenetriamine is 1:1.
5.
3. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 1), the synthesis temperature is 50-100°C.
4. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 1), the synthesis time is 5-24 hours.
5. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 2), the alcohol solution is selected from one or more of methanol, ethanol, isopropanol, and ethylene glycol.
6. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 2), the amount of the amino-terminated hyperbranched polymer NH2-HBP added to the alcohol solvent is 0.01%-0.1%.
7. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 2), the reaction temperature of adding the amino-terminated hyperbranched polymer NH2-HBP to the alcohol solvent is 20-50°C.
8. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: In the step 2), the reaction time of adding the amino-terminated hyperbranched polymer NH2-HBP to the alcohol solvent is 1-10 hours.
9. The method for removing metal impurities from electronic-grade solvent for photoresist according to claim 1, wherein: The content of each metal ion in the purified electronic grade solvent is less than 10 ppb.