Purification process of electronic-grade diluent

Abstract

The invention discloses a purification process of an electronic-grade diluent, which comprises the following steps: separating and purifying an industrial-grade crude product raw material containing beta-PGME and / or beta-PGMEA impurities in a rectification system with a specific reflux ratio of (3-5): 1, a segmentation ratio of (0.55-0.75) and at least 50 theoretical plates, preferably adopting a tandem double-tower vacuum rectification system, and controlling the temperature and pressure difference of a tower kettle. According to the invention, the contents of beta-PGME and beta-PGMEA in the product can be effectively reduced to 0.0030% or below and 0.0060% or below respectively, the problems of uneven thickness of a photoresist film, comet tail defects and the like caused by beta-isomer residues are fundamentally solved, and the photoetching process quality and the chip manufacturing yield are improved on the premise of ensuring reasonable productivity and energy consumption.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to a purification process for electronic-grade diluents. Background Technology

[0002] In semiconductor photolithography, electronic-grade diluents are key solvents in photoresist formulations or edge-repellent cleaning agents, and can also be used directly as edge-repellent cleaning agents. These include PGME (propylene glycol monomethyl ether) and PGMEA (propylene glycol monomethyl ether acetate). During industrial chemical production, due to the non-specificity of the reaction pathway, they inevitably produce structural isomer byproducts, mainly α-PGME (1-methoxy-2-propanol) and β-PGME (2-methoxy-1-propanol), as well as α-PGMEA (1-methoxy-2-propanol acetate) and β-PGMEA (2-methoxy-1-propanol acetate).

[0003] Although β-PGME and β-PGMEA are typically present in trace amounts in the final product, their physicochemical properties differ from those of the main component, the α-isomer. The β-isomer has a higher boiling point and a slower evaporation rate. During the pre-baking process after photoresist spin coating, its slow evaporation can lead to uneven solvent residue distribution, easily causing problems such as uneven film thickness, comet tail defects, edge bead thickening, and pinholes, severely impacting the quality of the photolithography pattern and the yield of chip manufacturing. Particularly for edge resist cleaners, if the β-isomer content is too high, it can cause an excessively rapid and uncontrollable dissolution rate of the photoresist, potentially resulting in excessively large dissolution pores or cleaning defects during edge resist cleaning.

[0004] Currently, industrial purification of PGME and PGMEA primarily relies on distillation technology. However, due to the close boiling points and similar physical properties of the α-isomer and β-isomer, effective separation via conventional distillation is difficult and costly. Existing technologies often face a trade-off between separation efficiency and production costs: improving separation accuracy typically leads to a sharp increase in energy consumption and a decrease in production capacity. Therefore, achieving precise control over the β-isomer content in PGME and PGMEA to meet ultra-high purity standards suitable for advanced semiconductor manufacturing, while maintaining reasonable production capacity and energy consumption, is a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a purification process for high-purity electronic-grade diluents of PGME and PGMEA, thereby making the content of the corresponding isomers in the final diluent extremely low, thus improving its cleaning effect in the photolithography process and reducing defects.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows.

[0007] In a first aspect, a purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and / or PGMEA containing β-PGME and / or β-PGMEA impurities; S200: The crude raw material is continuously fed into a distillation system for separation and purification; S300: The PGME and PGMEA products collected from the top of the distillation system are collected; The reflux ratio (R) of the distillation system is 3 to 5:1, the fractionation ratio (S) of the distillation system is 0.55 to 0.75, and the distillation system has at least one distillation column with more than 50 theoretical plates.

[0008] As a preferred technical solution, the distillation system includes a first distillation column and a second distillation column connected in series along the distillation feed direction, wherein the first distillation column has 30 to 50 theoretical plates and the second distillation column has 50 to 70 theoretical plates.

[0009] As a preferred technical solution, by weight percentage, in S100, the crude raw material contains β-PGME≤0.5% in PGME and β-PGMEA≤0.5% in PGMEA.

[0010] As a preferred technical solution, by weight percentage, in S300, the β-PGME content in the purified PGME product is ≤0.0030%, and the β-PGMEA content in the PGMEA product is ≤0.0060%.

[0011] As a preferred technical solution, the distillation system operates under reduced pressure conditions of 20~40 kPa; wherein, The bottom temperature of the first distillation column is controlled at 85~110℃; The bottom temperature of the second distillation column is controlled at 105~130℃; Furthermore, the operating pressure of the second distillation column is 5-15 kPa lower than that of the first distillation column.

[0012] As a preferred technical solution, after step S100 and before step S200, the crude raw material is further filtered, and the filtration adopts a microporous filter with a pore size of 0.1~0.5 micrometers.

[0013] As a preferred technical solution, the height of the first distillation column is 16~20m, and the height of the second distillation column is 21~25m; the theoretical number of plates (N) and the column height (H) of the distillation column are determined by the following formula: H=A×ln[N·(S / 0.6)]+C; Where A is the tray efficiency factor, with a value ranging from 3 to 5; S is the fractionation ratio of the distillation system; and C is the column height reference constant, with a value ranging from 5.0 to 7.0.

[0014] As a preferred technical solution, the theoretical number of trays N and the segmentation ratio S satisfy the relationship: N×S≥30.

[0015] As a preferred technical solution, a mid-infrared emitter is provided inside the first distillation column and / or the second distillation column. The mid-infrared emitter radiates the material inside the first distillation column and / or the second distillation column, exciting the molecular vibration of β-PGME or β-PGMEA molecules.

[0016] Secondly, the present invention provides an electronic-grade diluent, which is prepared by a process having at least one of the above-mentioned technical features.

[0017] The advantages and beneficial effects of this invention are as follows: By optimizing the reflux ratio, fractionation ratio, and theoretical plate number of the distillation system, efficient separation of the β-isomers in PGME and PGMEA is achieved; the process shown in this invention can reduce the content of β-PGME and β-PGMEA to below 0.0030% and 0.0060%, respectively, improving the purity of the electronic-grade diluent; thereby effectively reducing problems such as film inhomogeneity and comet tail defects caused by solvent residue in the photolithography process. While ensuring reasonable energy consumption and production capacity, it meets the demand for ultra-high purity diluents in advanced semiconductor manufacturing, thereby improving the quality of photolithography patterns and the yield of chip manufacturing. Attached Figure Description

[0018] Figure 1 This is the GC chromatogram of PGME before the modification of the distillation equipment of this invention.

[0019] Figure 2 This is the GC chromatogram of PGME after the distillation equipment of this invention was modified.

[0020] Figure 3 This is the GC chromatogram of PGMEA before the modification of the distillation equipment of this invention.

[0021] Figure 4 This is the GC chromatogram of PGMEA after the distillation equipment of this invention was modified.

[0022] Figure 5 This is a comparison chart showing the effect of photoresist before and after the modification of the distillation equipment of this invention.

[0023] Figure 6 This is a comparison chart of metal ion content before and after the modification of the distillation equipment of this invention. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0025] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly or implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0027] This invention provides a purification process for electronic-grade diluents, comprising the following steps: S100. Obtain industrial-grade crude PGME and / or PGMEA containing β-PGME and / or β-PGMEA impurities; S200: The crude raw material is continuously fed into the distillation system for separation and purification; S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0028] In this invention, the reflux ratio (R) of the distillation system is controlled between 3:1 and 5:1, the separation ratio (S) is controlled between 0.55 and 0.75, and the distillation system includes at least one distillation column with a theoretical plate number (N) of not less than 50. By optimizing the key operating parameters of the distillation system, this invention achieves efficient separation of the β-isomers in PGME and PGMEA, thereby reducing the contents of β-PGME and β-PGMEA in the product to below 0.0030% and 0.0060%, respectively.

[0029] Tables 1 and 2 show the effects of different isomers on photoresist performance.

[0030] Table 1: Properties a-PGME (major component) b-PGME (minor component) Effect on photoresist Boiling point about 118°C about 132°C Strongly affects drying kinetics: the difference in boiling point is about 14°C, which means that b-PGME evaporates much slower than a-PGME during the pre-bake after spin coating. This can lead to severe solvent residue and non-uniform distribution, posing a greater threat to film uniformity. Evaporation rate faster very slow Core defect source: the extremely slow evaporation rate makes it a "tail" solvent. After a-PGME evaporates rapidly, the remaining b-PGME is prone to cause various coating defects, such as comet tail, edge bead, etc., and the problem is more prominent than in PGMEA. Polarity / solubility standard higher (due to stronger activity of the hydroxyl group). Affects solubility behavior: stronger polarity can produce different solvation effects on photoresist resins, especially certain components with higher polarity. This can affect the storage stability of photoresist solution, the rheological properties before coating, and even after exposure, the contrast between the dissolution rate of the developing solution for exposed and unexposed areas, subtly changing the contrast Hydrogen bonding ability standard may be stronger Impacts on interfacial interactions: primary hydroxyl groups have stronger hydrogen bond donor and acceptor capabilities than secondary hydroxyl groups. This can impact the interfacial adhesion and wetting of photoresist to substrate layers (e.g., Si, SiO2, BARC). Table 2: Properties a-PGMEA (major component) b-PGMEA (minor component) Effect on photoresist Boiling point about 146°C about 149-152°C Affects drying process: b-PGMEA evaporates more slowly during the pre-bake after spin coating. This can lead to uneven distribution of solvent residue, affecting film uniformity and interfacial properties. Evaporation rate faster slower Defects: b-PGMEA, which evaporates slowly, can form tiny aerosols or droplets during the late drying stage, becoming a cause of comet tail defects, pinholes, etc. in photoresist films. Polarity / solubility standard solubility slightly different Affects solubility and stability: its different polarity can subtly affect the solubility of photoresist resins. During storage, this can affect the long-term stability of the photoresist solution, or the interfacial interaction with other components (such as the underlying layer) after coating. Because α-PGME and β-PGME have a greater boiling point difference, their evaporation is more asynchronous during pre-baking. This leads to greater internal stress and density gradient within the photoresist film, directly deteriorating the film thickness uniformity and consequently affecting the control of critical dimensions.

[0031] In chemically amplified photoresists, the polarity of the solvent affects the generation and diffusion of photoacids. The higher polarity of β-PGME can alter the dissolution rate difference between exposed and unexposed areas in the developer, thus affecting the sidewall shape and linewidth roughness of the final pattern. For photoresist manufacturers and chip manufacturers, batch-to-batch fluctuations in the β-PGME content of PGME raw materials represent a risk requiring close monitoring. Even small changes in content can cause significant variations in photoresist coating performance and defect rates, making process windows unstable and reducing the predictability of production yields.

[0032] Because PGME is a more basic solvent with a lower boiling point, the influence of its β-isomer is often more concerning than that of PGMEA. In high-end semiconductor manufacturing, the specifications for electronic-grade PGME are extremely stringent, with one key indicator being the strict control of β-PGME content. Suppliers utilize advanced synthesis catalysis and precision separation technologies to minimize this content. Chip manufacturers consider it a crucial aspect of incoming material inspection. Photoresist manufacturers also choose to use ultra-high purity PGME and PGMEA when formulating photoresists to ensure the stability and reproducibility of their product performance.

[0033] With the continuous advancement of integrated circuit technology, the requirements for the content of metal ions and non-metallic impurities in ultra-clean, high-purity reagents are becoming increasingly stringent. From ppm-level reagents used in general integrated circuits to ppb-level reagents used in very large-scale integrated circuits, and now to the even more demanding ppt-level reagents, the production processes for wet electronic chemicals are constantly being updated. Conventional trace element analysis methods include atomic absorption spectrophotometry, flame emission spectrometry, graphite furnace atomic absorption spectrometry, and inductively coupled plasma atomic emission spectrometry. The development trend of integrated circuits is towards submicron or deep submicron linewidths; therefore, inductively coupled plasma mass spectrometry (ICP-MS), with its higher detection precision, will become the primary analytical method. Gas chromatography (GC) is used as the primary analytical instrument for purity analysis.

[0034] Please see Figure 1- Figure 6In purification processes, the reflux ratio (R) refers to the ratio of the reflux liquid flow rate to the product flow rate during distillation, ranging from 3:1 to 5:1. The reflux ratio directly affects the mass transfer efficiency and component separation degree of the gas-liquid two-phase system within the column. When the reflux ratio is too low, the liquid phase reflux flow rate within the column is insufficient, leading to inadequate gas-liquid contact, reduced mass transfer driving force, and difficulty in effectively separating α-isomers and β-isomers with similar boiling points. This may also cause a decrease in tray efficiency and product purity. When the reflux ratio is too high, although the separation degree is improved, it leads to a sharp increase in energy consumption, a decrease in production capacity, and may cause operational instability phenomena such as flooding or entrainment. This invention achieves a reasonable balance between energy consumption and production capacity while ensuring high separation efficiency by controlling the reflux ratio within the range of 3:1 to 5:1, making it particularly suitable for the large-scale continuous production of electronic-grade diluents.

[0035] The fractionation ratio (S) refers to the ratio of product yield to feed rate in a distillation system, ranging from 0.55 to 0.75. The fractionation ratio reflects the distillation system's processing capacity for feedstock and product yield. When the fractionation ratio is too low, the product yield is low; although purity may slightly improve, it leads to decreased feedstock utilization, increased waste liquid, and poor overall process economy. When the fractionation ratio is too high, the product yield increases, but the rapid withdrawal may reduce the separation time in the column, resulting in incomplete impurity removal and excessive β-isomer residue. This invention, by limiting the fractionation ratio to between 0.55 and 0.75, ensures both high product yield and effective impurity removal, achieving an optimal match between purity and yield.

[0036] The theoretical plate number (N) is a crucial parameter for measuring the separation capacity of a distillation column, representing the ideal number of stages for achieving equilibrium between the gas and liquid phases. This invention requires the distillation system to include at least one distillation column with a theoretical plate number of not less than 50. The theoretical plate number directly determines the separation accuracy; a higher plate number results in better separation, but also increases equipment height, investment costs, and operating pressure drop. When the theoretical plate number is below 50, the column's separation capacity is insufficient, making it difficult to effectively separate α-isomers from β-isomers, and the β-isomer content in the product cannot meet electronic grade standards. While an excessively high theoretical plate number can further improve purity, it leads to excessive column height, increased manufacturing difficulty, increased energy consumption, and potential problems such as poor fluid flow.

[0037] The distillation system of this invention is preferably operated in continuous mode, enabling continuous feeding of crude feedstock and product recovery, ensuring process stability and large-scale production capacity. The distillation column employs a multi-stage tray structure to increase the gas-liquid contact area and mass transfer efficiency. During operation, precise control of temperature, pressure, and fluid distribution within the column ensures that the volatility and relative volatility differences of each component are fully utilized, thereby achieving efficient separation of β-PGME and β-PGMEA. A higher theoretical plate number allows for the same separation effect at a slightly lower reflux ratio, thus saving energy; while an optimized fractionation ratio ensures that ideal product yields are maintained even in a high-plate-number system.

[0038] In some embodiments, to further improve separation efficiency and operational flexibility, the distillation system includes a first distillation column and a second distillation column connected in series along the distillation feed direction, wherein the first distillation column has 30 to 50 theoretical plates and the second distillation column has 50 to 70 theoretical plates. This dual-column series configuration enables fractional processing of the crude feedstock, achieving both preliminary separation and deep purification. The first distillation column removes most of the light components and some β-isomers, reducing the load on the second distillation column; the second distillation column focuses on the deep removal of residual β-isomers, ensuring product purity meets electronic grade standards. The dual-column system allows for independent optimization of the operating parameters of each column, further enhancing the process adaptability and controllability.

[0039] In some embodiments, to ensure the stability of raw material quality and the repeatability of the process, in step S100, the crude raw material contains ≤0.5% β-PGME (PGME by weight) and / or ≤0.5% β-PGMEA (PGMEA by weight). Controlling the initial content of β-isomers in the raw material can preferably be within a certain range. If the β-isomer content in the raw material is too high, it will increase the load on the distillation system, leading to increased separation difficulty and decreased product purity.

[0040] In some embodiments, to meet the stringent purity requirements of advanced semiconductor manufacturing for diluents, in step S300, the β-PGME content in the purified PGME product is ≤0.0030% by weight, and / or the β-PGMEA content in the PGMEA product is ≤0.0060%. This purity level is far higher than industrial-grade standards, ensuring uniform solvent evaporation during spin coating and pre-baking of the photoresist, and avoiding problems such as uneven film thickness and comet tail defects. The electronic-grade diluent prepared by this process has excellent chemical stability and a low defect rate, and can be directly used in high-end photolithography processes.

[0041] In some embodiments, to reduce operating temperature and minimize the risk of degradation of heat-sensitive components, the distillation system operates under reduced pressure of 20 kPa to 40 kPa. Specifically, the reboiler temperature of the first distillation column is controlled at 85°C to 110°C; the reboiler temperature of the second distillation column is controlled at 105°C to 130°C; and the operating pressure of the second distillation column is 5 kPa to 15 kPa lower than that of the first distillation column. Reduced pressure operation lowers the boiling points of each component, avoiding solvent decomposition or polymerization side reactions caused by high temperatures. Precise control of the reboiler temperature ensures the stability of the gas-liquid balance within the column, while the lower pressure in the second distillation column facilitates further separation of high-boiling-point β-isomers, improving product purity.

[0042] In some embodiments, in order to remove particulate impurities and colloidal substances from the raw material and prevent clogging and contamination of the distillation system, a step of filtering the crude raw material is included after step S100 and before step S200, wherein the filter uses a microporous filter with a pore size of 0.1 micrometer to 0.5 micrometer.

[0043] In some embodiments, in order to optimize the structural design of the distillation column and establish a quantitative relationship between column height and separation performance, the first distillation column has a height of 16m to 20m, and the second distillation column has a height of 21m to 25m.

[0044] The theoretical number of trays (N) and the height (H) of the distillation column are determined by the following formula: H=A×ln[N·(S / 0.6)]+C, where A is the tray efficiency factor, ranging from 3 to 5; S is the fractionation ratio of the distillation system; and C is the column height reference constant, ranging from 5.0 to 7.0.

[0045] The above formula comprehensively considers the influence of the number of trays, the fractionation ratio, and the column efficiency on the column height, providing a basis for the engineering design of distillation columns. When the value of A is small, it indicates that the tray efficiency is high and the required column height is low; when the value of A is large, the column height needs to be increased to compensate for the efficiency loss. By adjusting the values ​​of A and C, the column structure can be designed for different raw material properties and product requirements, achieving the optimal configuration of equipment investment and separation performance. The quantitative relationship between column structure and separation performance comprehensively considers the requirements of tray efficiency and separation difficulty on the actual column height.

[0046] In conventional distillation column design, column height and the number of theoretical plates are usually considered to have an approximately linear relationship or are corrected using empirical coefficients. This invention, however, introduces a natural logarithmic function to correlate these parameters. The effective column height increment required for each additional theoretical plate is not constant but decreases. This nonlinear relationship aligns better with the fundamental laws of fluid mechanics and mass transfer, namely, that column efficiency exhibits nonlinear characteristics with column height. By introducing a plate efficiency factor (A) and a separation ratio (S), this model dynamically couples the separation difficulty and equipment structure, providing an accurate theoretical basis for predicting the optimal column height for a given separation task. This avoids insufficient separation capacity or wasted equipment investment caused by relying solely on empirical design.

[0047] In some embodiments, to ensure the separation stability of the distillation system under a wide range of operating conditions, the theoretical number of plates (N) and the fractionation ratio (S) satisfy the relationship: N×S≥30. This relationship reflects the synergistic effect of the number of plates and the fractionation ratio, and their product can serve as a comprehensive indicator of the overall separation capability of the system. When N×S is below 30, the system's separation capability is insufficient, and product purity is difficult to guarantee; while when N×S is too high, although it is beneficial to improve purity, it may lead to a decrease in operational flexibility and an increase in equipment costs.

[0048] In some embodiments, to enhance the activity and separation selectivity of β-isomer molecules, a mid-infrared emitter is installed inside the second distillation column. The mid-infrared emitter radiates the material in the first and / or second distillation columns, exciting the molecular vibrations of β-PGME or β-PGMEA molecules. Mid-infrared radiation can specifically excite the CO bond and methyl vibration modes in β-isomer molecules, altering their polarity and volatility, thereby increasing the relative volatility difference with the α-isomer. This physical field-assisted separation technology improves separation efficiency and product purity without introducing chemical reagents, and is suitable for the deep removal of trace impurities. Furthermore, mid-infrared radiation has advantages such as low energy consumption, no pollution, and easy integration, providing an enhanced effect for the distillation process.

[0049] This invention incorporates a mid-infrared emitter within the second distillation column, utilizing the selective absorption of the mid-infrared band by specific chemical bonds in the β-PGME / β-PGMEA molecules. When the β-isomer molecule is exposed to infrared radiation matching its molecular vibrational frequency, resonant absorption occurs, leading to molecular vibrational energy level transitions and intensified thermal motion. This fine-tunes its volatility properties, increasing the relative volatility difference between it and the α-isomer. Under the same distillation conditions, the β-isomer tends to enter the gas phase, achieving deep removal of trace amounts of difficult-to-separate isomers without introducing a third component or altering the product's chemical composition.

[0050] Specifically, the emission wavelength of the mid-infrared emitter is preferably 3.0 μm to 5.0 μm, based on the characteristic absorption peaks of the target impurity molecules (β-PGME and β-PGMEA). The combination and overtone absorptions of the stretching vibrations of CH bonds, OH bonds, and the stretching and bending vibrations of CO bonds in organic molecules mostly fall in the mid-infrared region, especially 3.3 μm to 3.5 μm (corresponding to CH stretching vibration) and 4.0 μm to 4.5 μm.

[0051] The β-isomer has its methoxy group (-OCH3) attached to a secondary carbon atom, while the hydroxyl group (-OH, for PGME) or ester group (-OCOCH3, for PGMEA) is attached to a primary carbon atom. This specific connection mode results in the combination or overtone absorption of specific COC asymmetric stretching vibrations and CH bending vibrations attached to the secondary carbon in its molecular skeleton. The vibrational frequencies corresponding to the α-isomer are in the mid-infrared region (especially the 4.2 μm ~ 4.5 μm band).

[0052] By matching the radiation wavelength to the intrinsic vibrational frequencies of these molecular bonds, resonant absorption can be achieved, thereby efficiently transferring infrared energy to β-isomer molecules, causing vibrational energy level transitions and intensifying molecular thermal motion. This selective energy injection can instantaneously and locally increase the effective temperature of β-isomer molecules, thereby increasing their relative volatility with the α-isomer. Under the same distillation conditions, the β-isomer tends to enter the gas phase and is thus more effectively separated and removed from the top of the column. The power density of the mid-infrared emitter is preferably controlled at 50 W / m². 2 ~200W / m 2 .

[0053] Specifically, the installation location of the mid-infrared emitter is marked by H=A / 3×ln[N·(S / 0.6)]+C / 2. This region corresponds to the mass transfer zone with moderate gas-liquid phase loading and relatively high β-isomer concentration within the column height range required for deep separation, as calculated by the model. Applying mid-infrared radiation at this location can most effectively target the most challenging stage of separation. Its energy field can cover the necessary separation path length precisely defined by the model, ensuring that β-isomer molecules in the vapor rising from the bottom of the column are sufficiently enriched and separated after undergoing a adequate, radiation-excited mass transfer process.

[0054] The purification process of this invention can be modified and optimized in various ways according to actual production needs. For example, a preheater can be added before the feed to the distillation system to preheat the crude raw material, thereby reducing the heat load on the reboiler and improving energy efficiency; in the top condensation system, a staged condensation method can be adopted to further separate light component impurities; during the product collection stage, the β-isomer content can be monitored in real time using an online analyzer to achieve closed-loop control and quality traceability. These supplementary measures further improve the reliability, economy, and product quality consistency of the process.

[0055] [Example 1] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw material contains 0.5% β-PGME and 0.5% β-PGMEA. Filter the crude raw material using a microporous filter with a pore size of 0.1 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 30 theoretical plates, and the second distillation column has 55 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 3:1, and the fractionation ratio (S) is controlled at 0.55. The distillation system operates under reduced pressure of 40 kPa, wherein the reboiler temperature of the first distillation column is controlled at 85°C, and the reboiler temperature of the second distillation column is controlled at 105°C. The operating pressure of the second distillation column is 5 kPa lower than that of the first distillation column. The height of the first distillation column is 16 m, and the height of the second distillation column is 21 m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H = A × ln[N·(S / 0.6)] + C, where for the first distillation column, A = 3 and C = 6.1, and for the second distillation column, A = 4 and C = 5.3. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N × S ≥ 30 (N × S = 55 × 0.55 = 30.25 for the second distillation column). S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0056] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0030% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0060%.

[0057] [Example 2] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw material contains 0.4% β-PGME and 0.4% β-PGMEA. Filter the crude raw material using a microporous filter with a pore size of 0.2 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 40 theoretical plates, and the second distillation column has 60 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 4:1, and the fractionation ratio (S) is controlled at 0.60. The distillation system operates under reduced pressure of 35 kPa, wherein the reboiler temperature of the first distillation column is controlled at 95°C, and the reboiler temperature of the second distillation column is controlled at 115°C. The operating pressure of the second distillation column is 10 kPa lower than that of the first distillation column. The height of the first distillation column is 18 m, and the height of the second distillation column is 23 m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H = A × ln[N·(S / 0.6)] + C, where for the first distillation column, A = 3.5 and C = 6.5, and for the second distillation column, A = 4.5 and C = 5.5. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N × S ≥ 30 (N × S = 60 × 0.60 = 36 for the second distillation column). S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0058] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0030% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0060%.

[0059] [Example 3] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA raw materials containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw materials contain 0.3% β-PGME and 0.3% β-PGMEA. Filter the crude raw materials using a microporous filter with a pore size of 0.3 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 50 theoretical plates, and the second distillation column has 70 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 5:1, and the fractionation ratio (S) is controlled at 0.65. The distillation system operates under reduced pressure of 30 kPa, wherein the reboiler temperature of the first distillation column is controlled at 100°C, and the reboiler temperature of the second distillation column is controlled at 125°C. The operating pressure of the second distillation column is 10 kPa lower than that of the first distillation column. The height of the first distillation column is 20 m, and the height of the second distillation column is 25 m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H = A × ln[N·(S / 0.6)] + C, where for the first distillation column, A = 4 and C = 7.0, and for the second distillation column, A = 5 and C = 6.0. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N × S ≥ 30 (N × S = 70 × 0.65 = 45.5 for the second distillation column). S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0060] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0030% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0060%.

[0061] [Example 4] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw material contains 0.5% β-PGME and 0.5% β-PGMEA. Filter the crude raw material using a microporous filter with a pore size of 0.4 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 35 theoretical plates, and the second distillation column has 65 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 3:1, and the fractionation ratio (S) is controlled at 0.70. The distillation system operates under reduced pressure of 25 kPa, wherein the reboiler temperature of the first distillation column is controlled at 90°C, and the reboiler temperature of the second distillation column is controlled at 110°C. The operating pressure of the second distillation column is 10 kPa lower than that of the first distillation column. The height of the first distillation column is 17 m, and the height of the second distillation column is 22 m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H = A × ln[N·(S / 0.6)] + C, where for the first distillation column, A = 3.2 and C = 6.2, and for the second distillation column, A = 4.2 and C = 5.8. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N × S ≥ 30 (N × S = 65 × 0.70 = 45.5 for the second distillation column). S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0062] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0030% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0060%.

[0063] [Example 5] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw material contains 0.4% β-PGME and 0.4% β-PGMEA. Filter the crude raw material using a microporous filter with a pore size of 0.5 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 45 theoretical plates, and the second distillation column has 55 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 4:1, and the fractionation ratio (S) is controlled at 0.75. The distillation system operates under reduced pressure of 20 kPa, wherein the reboiler temperature of the first distillation column is controlled at 110°C, the reboiler temperature of the second distillation column is controlled at 130°C, and the operating pressure of the second distillation column is 10 kPa lower than that of the first distillation column. The height of the first distillation column is 19 meters. The second distillation column has a height of 24m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H=A×ln[N·(S / 0.6)]+C, where for the first distillation column, A=3.8 and C=6.8, and for the second distillation column, A=4.8 and C=6.2. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N×S≥30 (N×S=55×0.75=41.25 for the second distillation column). The second distillation column is equipped with a mid-infrared emitter, which radiates the material inside the second distillation column to excite the molecular vibration of β-PGME or β-PGMEA molecules. S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0064] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0025% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0050%.

[0065] [Example 6] A purification process for an electronic-grade diluent includes the following steps: S100. Obtain industrial-grade crude PGME and PGMEA containing β-PGME and β-PGMEA impurities. By weight percentage, the crude raw material contains 0.3% β-PGME and 0.3% β-PGMEA. Filter the crude raw material using a microporous filter with a pore size of 0.5 micrometers. S200. The crude raw material is continuously fed into a distillation system for separation and purification. The distillation system includes a first distillation column and a second distillation column connected in series along the feed direction. The first distillation column has 40 theoretical plates, and the second distillation column has 60 theoretical plates. The reflux ratio (R) of the distillation system is controlled at 5:1, and the fractionation ratio (S) is controlled at 0.65. The distillation system operates under reduced pressure of 30 kPa, wherein the reboiler temperature of the first distillation column is controlled at 110°C, the reboiler temperature of the second distillation column is controlled at 130°C, and the operating pressure of the second distillation column is 10 kPa lower than that of the first distillation column. The height of the first distillation column is 1 meter. The height of the first distillation column is 9m, and the height of the second distillation column is 24m. The theoretical number of plates (N) and the column height (H) of the distillation column satisfy the following relationship: H=A×ln[N·(S / 0.6)]+C, where for the first distillation column, A=3.5 and C=6.5, and for the second distillation column, A=4.5 and C=6.0. The theoretical number of plates (N) and the fractionation ratio (S) satisfy the following relationship: N×S≥30 (N×S=60×0.65=39 for the second distillation column). The second distillation column is equipped with a mid-infrared emitter, which radiates the material inside the second distillation column to excite the molecular vibration of β-PGME or β-PGMEA molecules. S300 collects PGME and PGMEA products extracted from the top of the distillation system.

[0066] In the electronic-grade diluent products prepared in this embodiment, the β-PGME content in the PGME product is ≤0.0020% by weight, and the β-PGMEA content in the PGMEA product is ≤0.0040%.

[0067] Please see Figure 1- Figure 4 The chromatogram of high-purity PGME and PGMEA products obtained by the purification process described in a certain embodiment of the present invention as electronic-grade diluents, and the distillate obtained in this embodiment is immediately filtered through 0.05μm and 0.02μm filter cartridges to remove particles to obtain a diluent required by the composite semiconductor industry.

[0068] The above-mentioned diluent is transported to a mixing tank in a certain proportion and mixed evenly with other raw materials. Then, it is passed through an ion exchange membrane for ion exchange and through an ultrafiltration membrane with a pore size of 0.1μm to 0.05μm for particle filtration. Finally, an ultra-high purity electronic grade edge adhesive cleaner with a metal ion content of less than 30ppt and an extremely low β-isomer content is obtained.

[0069] Figure 5 and Figure 6 The comparison of the effects and metal ion content of this type of edge adhesive cleaner is shown separately. Figure 5 In the image, the left side shows the effect of using the original electronic-grade diluent, while the right side shows the effect of using the electronic-grade diluent after equipment modification.

[0070] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A purification process for an electronic-grade diluent, characterized in that, Includes the following steps: S100. Obtain industrial-grade crude PGME and / or PGMEA containing β-PGME and / or β-PGMEA impurities; S200: The crude raw material is continuously fed into a distillation system for separation and purification; S300 collects PGME and PGMEA products drawn from the top of the distillation system column; The reflux ratio (R) of the distillation system is controlled between 3:1 and 5:1, the split ratio (S) is controlled between 0.55 and 0.75, and the distillation system includes at least one distillation column with a theoretical plate number (N) of not less than 50.

2. The purification process for the electronic-grade diluent according to claim 1, characterized in that, The distillation system includes a first distillation column and a second distillation column connected in series along the distillation feed direction. The first distillation column has 30 to 50 theoretical plates, and the second distillation column has 50 to 70 theoretical plates.

3. The purification process for the electronic-grade diluent according to claim 1, characterized in that, In step S100, by weight percentage, the crude raw material contains β-PGME ≤ 0.5% of PGME and / or β-PGMEA ≤ 0.5% of PGMEA.

4. The purification process for the electronic-grade diluent according to claim 1, characterized in that, In step S300, the β-PGME content in the purified PGME product is ≤0.0030% by weight, and / or the β-PGMEA content in the PGMEA product is ≤0.0060%.

5. The purification process for the electronic-grade diluent according to claim 2, characterized in that, The distillation system operates under reduced pressure conditions of 20 kPa to 40 kPa; The bottom temperature of the first distillation column is controlled at 85°C to 110°C. The reboiler temperature of the second distillation column is controlled at 105°C to 130°C; Furthermore, the operating pressure of the second distillation column is 5 kPa to 15 kPa lower than that of the first distillation column.

6. The purification process for the electronic-grade diluent according to claim 1, characterized in that, After step S100 and before step S200, the process further includes a step of filtering the crude raw material, wherein the filtration employs a microporous filter with a pore size of 0.1 micrometers to 0.5 micrometers.

7. The purification process for the electronic-grade diluent according to claim 2, characterized in that, The first distillation column has a height of 16m to 20m, and the second distillation column has a height of 21m to 25m; The theoretical number of trays (N) and the height (H) of the distillation column are determined by the following formula: H = A × ln[N·(S / 0.6)] + C, A is the tray efficiency factor, ranging from 3 to 5; S is the fractionation ratio of the distillation system; C is the column height reference constant, ranging from 5.0 to 7.

0.

8. The purification process for the electronic-grade diluent according to claim 1 or 7, characterized in that, The theoretical number of plates (N) and the segmentation ratio (S) satisfy the following relationship: N×S≥30.

9. The purification process for the electronic-grade diluent according to claim 2, characterized in that, The second distillation column is equipped with a mid-infrared emitter, which radiates to the material in the first and / or second distillation columns to excite the molecular vibration of β-PGME or β-PGMEA molecules.

10. An electronic-grade diluent, characterized in that, It is prepared by the purification process described in any one of claims 1 to 9.

Images