Fluorine-containing resin material purification treatment method for semiconductor-grade electronic chemicals

Abstract

The invention belongs to the technical field of electronic chemical materials for semiconductors, and particularly relates to a purification treatment method of a fluorine-containing resin material for semiconductor-grade electronic chemicals, which comprises the following process steps: water washing, acid pickling, soaking pretreatment, acid soaking cleaning, water washing and drying. Compared with the prior art, the method provided by the invention has the advantages that the metal ion precipitation rate is higher and the precipitation amount is higher in the cleaning process, so that the metal ion precipitation amount of the cleaned PFA resin in the use process is smaller, and the purified high-end fluorine-containing resin material can reach a semiconductor level; the use requirements of semiconductor-grade electronic chemicals on the ultra-clean high-purity fluorine-containing resin are met, and the application of domestic resin materials in semiconductor-grade pipes is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic chemical materials for semiconductors, and in particular relates to a purification method for fluorine-containing resin materials for semiconductor-grade electronic chemicals. Background Art

[0002] Semiconductor manufacturing processes are developing very rapidly, with narrower line widths and smaller chip sizes. Therefore, the cleanliness requirements for wet electronic chemicals used in the manufacturing process are becoming more and more stringent. Currently, mainstream 12-inch wafer foundries have reached G5 level for wet electronic chemicals. The G5 level standard for wet electronic chemicals requires a single metal ion impurity content of: metal ion content <10ng / kg.

[0003] The pipes used in the production process of wet electronic chemicals are basically made of ultra-clean, high-purity fluorinated polymer materials represented by PTFE and PFA. After the fluorinated resin materials are processed into pipes, valves and other components, they come into contact with wet electronic chemicals, resulting in a high amount of metal ion precipitation. The degree of impurity precipitation directly affects the quality of wet electronic chemicals. At present, the fluorinated resin materials produced domestically have a high amount of metal ion precipitation during use, which is far behind the product quality of leading foreign companies and cannot meet the requirements of semiconductor electronic chemicals for material use. Therefore, the preparation of ultra-clean, high-purity fluorinated resin materials for wet electronic chemicals has also become a bottleneck technology in the domestic semiconductor industry chain.

[0004] At present, there is overcapacity and fierce competition in the low-end field of fluororesin materials in my country. Because domestically produced fluororesin materials have a high metal ion precipitation during use, they cause pollution to electronic chemicals during use and cannot meet the requirements of semiconductor-grade wet electronic chemical raw materials. In order to solve the preparation of ultra-clean and high-purity fluororesin raw materials for wet electronic chemicals, a purification method for ultra-clean and high-purity fluororesin materials for semiconductor-grade electronic chemicals is provided to improve the quality of domestic fluororesin products and reduce the amount of metal ion precipitation during use. Summary of the invention

[0005] In order to solve the problem in the above-mentioned prior art that impurities such as metal ions are introduced into the current domestic high-end fluororesin materials during the processing, and there is no effective purification treatment technology at the back end, resulting in a high amount of metal ion precipitation in the material during use, the present invention provides a purification treatment method for fluororesin materials for semiconductor-grade electronic chemicals, which reduces the amount of metal ion impurities precipitated in the fluororesin production process. The purified high-end fluororesin materials can reach the semiconductor-grade level, meeting the requirements of semiconductor-grade electronic chemicals for the use of ultra-clean and high-purity fluororesins.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals comprises the following process steps:

[0008] (1) Water washing: Use ultrapure water to wash the fluorine-containing resin to remove impurities attached to the resin surface.

[0009] (2) Acid washing: After water washing, the sample is cleaned with inorganic acid instead of ultrapure water. This step has the following beneficial effects: the inorganic acid has a smaller molecular weight and stronger penetration, and can react with impurities such as metal ions in the material, dissolve and remove them, making the raw material purer.

[0010] (3) Pre-immersion treatment: Use organic solvent to soak the fluorine-containing resin material to destroy the hydrophobic groups of the fluorine-containing resin; this step has the following beneficial effects: after treatment with organic solvent, the fluorine-containing material and the inorganic acid can have more extensive contact, which is conducive to the reaction and better removal of impurities.

[0011] (4) Acid immersion cleaning: Use inorganic acid with small molecular weight and strong permeability as the pickling material, and perform deep immersion cleaning on the resin material through the pickling process to fully remove the metal ion impurities introduced into the resin material during the production process. This step has the following beneficial effects: the use of inorganic acid can react with the metal ions, inorganic substances and other impurities introduced into the fluorine-containing resin during the production process, dissolve them, and make the raw material purer;

[0012] (5) Washing: After the soaking is completed, the inorganic acid and the fluorine-containing resin are separated by filtration, and the fluorine-containing resin is washed with ultrapure water, and the washing is repeated until the pH value of the ultrapure water is neutral;

[0013] (6) Drying: The cleaned fluorine-containing resin is filtered and placed in a dryer to dry out the moisture to obtain the final product.

[0014] Preferably, in step (1), the fluorine-containing resin is washed and soaked in ultrapure water with a metal ion content of less than 10 ng / kg, and the ultrapure water is drained after being evenly shaken and soaked for more than 2 minutes, and the above operation is repeated for more than 6 times.

[0015] Preferably, in step (2), an inorganic acid with a metal ion content of ≤10 ng / kg (which has the following beneficial effects: selecting an inorganic acid with high cleanliness to reduce the introduction of impurities) is used instead of ultrapure water to clean the sample, and the sample is evenly shaken for more than 2 minutes and soaked for about 2-5 hours to drain the inorganic acid, and the above operation is repeated 2-6 times.

[0016] Preferably, in step (3), the fluorine-containing resin material is impregnated with an organic solvent in a volume ratio of 4:5 to 2:5.

[0017] Preferably, in step (3), the organic solvent is a mixed solvent of propanol and ethanol, and the volume ratio of propanol to ethanol is 1:1; this has the following beneficial effects: the selection of these two solvents can help the inorganic acid to better contact the fluorine-containing resin material, and the solvent is easy to remove in the subsequent process, reducing other effects on the material.

[0018] Preferably, in step (4), the fluorine-containing resin is immersed in an inorganic acid with a metal ion content of ≤10 ng / kg at a ratio of 1:60 to 1:80, and heated and stirred. Samples are taken at intervals of 24 h, 48 h, and 72 h to analyze the precipitation of metal ions. When the metal ions in the solution no longer increase, the immersion is terminated.

[0019] Beneficial Effects

[0020] The present invention discloses a method for purifying a fluorine-containing resin material for semiconductor-grade electronic chemicals. Compared with the prior art, the present invention has the following beneficial effects:

[0021] Compared with the prior art, the method described in the present application has a faster metal ion precipitation rate and a higher precipitation amount during the cleaning process, ensuring that the cleaned PFA resin has less metal ion precipitation during use, thereby improving the application of domestic resin materials in semiconductor-grade pipes.

[0022] Compared with the prior art, the method of the present application adopts an inorganic acid with smaller molecular weight and higher penetration, and at the same time adds an organic solvent soaking process before cleaning, which improves the cleaning penetration rate and greatly improves the amount and rate of metal ion precipitation, ensuring that the PFA resin after soaking meets the use requirements of raw materials for the manufacture of ultra-clean high-purity wet electronic chemical pipes.

[0023] The method described in this application uses inorganic acid as a pickling agent, which has a higher permeability than other materials and can penetrate the gaps of the surface molecular chains of fluororesins such as PTFE and PFA better than other chemicals. At the same time, inorganic acid can fully dissolve impurities such as metal ions attached to fluororesin materials. Compared with the current field of purification and processing of fluororesin materials, only some manufacturers use ultrapure water to soak fluororesin materials, which cannot fully deal with the precipitation of metal ion impurities in fluororesins.

[0024] The method described in this application proposes a purification process for fluorine-containing resin materials based on the characteristics of inorganic acids, and creatively adds organic solvents to destroy the hydrophobic groups of fluorine-containing resins during the early treatment process, so that the inorganic acid pickling and soaking can achieve better treatment and purification effects. The purified high-end fluorine-containing resin materials can reach semiconductor-grade levels.

[0025] Compared with the fluorine-containing resin materials in the prior art, the fluorine-containing resin material finally obtained by the method of the present invention has the following advantages and improvements: it has the advantage of low metal ion precipitation. When the treated fluorine-containing resin is made into pipes and valves for conveying materials in the semiconductor field, the low metal ion precipitation can reduce the pollution of the materials. During the production process of the fluorine-containing resin, some impurities such as metal ions and inorganic substances may exist. The use of inorganic acid pickling can react chemically with these impurities, dissolve and remove them, and make the raw materials purer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : A schematic diagram of the process flow of a method for purifying a fluorine-containing resin material for semiconductor-grade electronic chemicals according to the present invention;

[0027] Figure 2 : Comparison chart of the test data of the final product obtained in Example 1 and the raw material before treatment;

[0028] Figure 3 : Comparison chart of the test data of the final product obtained in Example 2 and the raw material before treatment;

[0029] Figure 4 : Data diagram of metal ion precipitation of each sample in Example 3 of the present invention;

[0030] Figure 5 : Metal ion precipitation data diagram of each sample in Example 4 of the present invention. DETAILED DESCRIPTION

[0031] Hereinafter, the present invention will be described in detail. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present invention, so that it should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0032] The following examples are only listed as examples of embodiments of the present invention and do not constitute any limitation to the present invention. It can be understood by those skilled in the art that modifications within the scope of the essence and concept of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0033] Example 1

[0034] A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals, comprising the following process steps:

[0035] ① Water washing: Wash and soak the fluorine-containing resin in ultrapure water with metal ions less than 10ng / kg. Shake and soak evenly for more than 2 minutes, then drain the ultrapure water. Repeat the above operation for more than 6 times.

[0036] ② Acid washing: After water washing, use inorganic acid with metal ions ≤10ng / kg instead of ultrapure water to clean the sample, shake it evenly for more than 2 minutes, soak it for about 2 hours, drain the inorganic acid, and repeat the above operation 6 times.

[0037] ③ Pre-immersion treatment: Use organic solvents (propanol, ethanol) in a ratio of 4:5 to soak the fluorine-containing resin material to destroy the hydrophobic groups of the fluorine-containing resin;

[0038] ④ After treatment, immerse the fluorine-containing resin in an inorganic acid with a metal ion of ≤10ng / kg at a ratio of 1:60, and heat and stir. Take samples at intervals of 24h, 48h, and 72h to analyze the precipitation of metal ions. When the metal ions in the solution no longer increase, the immersion is terminated.

[0039] ⑤After soaking, filter and separate the inorganic acid and fluorine-containing resin, wash the fluorine-containing resin with ultrapure water, and repeat the washing until the pH value of the ultrapure water is neutral;

[0040] ⑥ Filter the cleaned fluorine-containing resin and put it into a dryer to dry the moisture to obtain the final product.

[0041] In order to demonstrate the beneficial effects of the method described in the present application, the performance parameters of the final product obtained in this example and the raw materials before treatment were tested respectively. The testing method is as follows: ICP-MS is used to detect the amount of metal ion precipitation.

[0042] Specific test comparison data such as Figure 2 shown.

[0043] Through the analysis of experimental data, the metal ion precipitation of the particles after acid washing and soaking is significantly reduced compared with the particles without acid washing and soaking. According to the experimental results, after treatment by this method, the fluorine-containing numerical mass can be significantly purified.

[0044] Example 2

[0045] A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals, comprising the following process steps:

[0046] ① Water washing: Wash and soak the fluorine-containing resin in ultrapure water with metal ions less than 10ng / kg. Shake and soak evenly for more than 2 minutes, then drain the ultrapure water. Repeat the above operation for more than 6 times.

[0047] ② Acid washing: After water washing, use inorganic acid with metal ion ≤10ng / kg instead of ultrapure water to clean the sample, shake it evenly for more than 2 minutes, soak it for about 3 hours, drain the inorganic acid, and repeat the above operation 3 times.

[0048] ③ Pre-immersion treatment: Use organic solvents (propanol, ethanol) in a ratio of 2:5 to soak the fluorine-containing resin material to destroy the hydrophobic groups of the fluorine-containing resin;

[0049] ④ After treatment, immerse the fluorine-containing resin in an inorganic acid with a metal ion content of ≤10ng / kg at a ratio of 1:80, and heat and stir. Take samples at intervals of 24h, 48h, and 72h to analyze the precipitation of metal ions. When the metal ions in the solution no longer increase, the immersion is terminated.

[0050] ⑤After soaking, filter and separate the inorganic acid and fluorine-containing resin, wash the fluorine-containing resin with ultrapure water, and repeat the washing until the pH value of the ultrapure water is neutral;

[0051] ⑥ Filter the cleaned fluorine-containing resin and put it into a dryer to dry the moisture to obtain the final product.

[0052] In order to demonstrate the beneficial effects of the method described in the present application, the performance parameters of the final product obtained in this example and the raw materials before treatment were tested respectively. The testing method is as follows: ICP-MS is used to detect the amount of metal ion precipitation.

[0053] Specific test comparison data such as Figure 3 shown.

[0054] Through the analysis of experimental data, the metal ion precipitation of the particles after acid washing and soaking is significantly reduced compared with the particles without acid washing and soaking. According to the experimental results, after treatment by this method, the fluorine-containing numerical mass can be significantly purified.

[0055] Example 3: Effect of pellet crushing experiment on metal precipitation

[0056] A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals. The specific method and process conditions are as follows:

[0057] (1) Prepare four clean 500 ml PFA bottles: numbered A01, A02, A03, and A04.

[0058] (2) Wash A01, A02, A03, and A04 with UPW for more than 6 times, shaking evenly each time. After washing, add about 500 ml of UPW.

[0059] (3) Pour out UPW, weigh 10 g each of PFA pellets (uncrushed) sample 1 and sample 2, and add them to bottles A01 and A02 respectively; weigh 10 g each of PFA pellets (crushed and washed with UPW) sample 3 and sample 4, and add them to bottles A03 and A04 respectively.

[0060] (4) Fill A01, A02, A03 and A04 with 500 ml of inorganic acid. Take samples and analyze the metal ion content of the inorganic acid before filling. The inorganic acid to be filled should be products from the same batch.

[0061] (5) After standing for 24 h (calculated based on the time of acid addition), analyze the metal ions of A01, A02, A03, and A04.

[0062] (6) After standing for 72 h (calculated based on the time of acid addition), analyze the metal ions of A01, A02, A03, and A04.

[0063] (7) After standing for 7 days (calculated based on the time of acid addition), analyze the metal ions of A01, A02, A03, and A04.

[0064] (8) After the soaking is completed, the inorganic acid and the fluorine-containing resin are separated by filtration, and the fluorine-containing resin is washed with ultrapure water, and the washing is repeated until the pH value of the ultrapure water is neutral;

[0065] (9) Filter the cleaned fluorine-containing resin and put it into a dryer to dry the moisture to obtain the final product.

[0066] Summary: Through experiments, it is found that metal ions precipitate out of PFA after pickling and soaking. Through data analysis, the amount of metal ion precipitation in crushed particles is greater than that in uncrushed particles. According to the experimental results, the metal ion precipitation effect of PFA powder is best under crushing conditions. For specific data, please see the attached Figure 4 .

[0067] Example 4: Effect of adding organic solvent on metal precipitation

[0068] A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals. The specific method and process conditions are as follows:

[0069] (1) Prepare four clean 500 ml PFA bottles: number B01, B02, B03, and B04.

[0070] (2) Wash A01, A02, A03, and A04 with UPW for more than 6 times, shaking evenly each time. After washing, add about 500 ml of UPW.

[0071] (3) Pour out UPW, weigh 10 g each of PFA pellets sample 1 and sample 2, and add them to bottles B01 and B02 respectively. Weigh 10 g each of PFA pellets sample 3 and sample 4, and use organic solvents in a ratio of 4:5 to 2:5 to soak the fluorine-containing resin material before soaking for more than 2 hours. After cleaning with UPW, add them to bottles B03 and B04 respectively.

[0072] (4) Fill B01, B02, B03, and B04 with 500 ml of inorganic acid. Before filling, take samples and analyze the metal ion content of the inorganic acid. The inorganic acid to be filled should be products from the same batch.

[0073] (5) After standing for 24 h (calculated based on the time of acid addition), analyze the metal ions of B01, B02, B03, and B04.

[0074] (6) After standing for 72 h (calculated based on the time of acid addition), analyze the metal ions of B01, B02, B03, and B04.

[0075] (7) After standing for 7 days (calculated based on the time of acid addition), analyze the metal ions of B01, B02, B03, and B04B.

[0076] (8) After the soaking is completed, the inorganic acid and the fluorine-containing resin are separated by filtration, and the fluorine-containing resin is washed with ultrapure water, and the washing is repeated until the pH value of the ultrapure water is neutral;

[0077] (9) Filter the cleaned fluorine-containing resin and put it into a dryer to dry the moisture to obtain the final product.

[0078] Summary: Through the analysis of experimental data, the metal ion precipitation rate of the soaked particles is higher than that of the unsoaked particles. According to the experimental results, the metal ion precipitation effect of PFA particles after soaking is the best. For specific data, please see the attached Figure 5 .

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals, characterized in that: The process steps include: (1) Water washing: Use ultrapure water to wash the fluorine-containing resin to remove impurities attached to the resin surface; (2) Acid washing: After water washing, use inorganic acid instead of ultrapure water to clean the sample; (3) Pre-immersion treatment: Use organic solvent to soak the fluorine-containing resin material to destroy the hydrophobic groups of the fluorine-containing resin; (4) Acid immersion cleaning: Use inorganic acid with small molecular weight and strong permeability as the pickling material, and use the pickling process to deeply immerse and clean the resin material to fully remove the metal ion impurities introduced into the resin material during the production process; (5) Washing: After the soaking is completed, the inorganic acid and the fluorine-containing resin are separated by filtration, and the fluorine-containing resin is washed with ultrapure water, and the washing is repeated until the pH value of the ultrapure water is neutral; (6) Drying: The cleaned fluorine-containing resin is filtered and placed in a dryer to dry out the moisture to obtain the final product.

2. The method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals according to claim 1, characterized in that: In step (1), the fluorine-containing resin is washed and soaked in ultrapure water with a metal ion content of less than 10 ng / kg, and the ultrapure water is drained after being evenly shaken and soaked for more than 2 minutes. The above operation is repeated for more than 6 times.

3. The method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals according to claim 1, characterized in that: In step (2), the sample is cleaned with an inorganic acid having a metal ion content of ≤10 ng / kg instead of ultrapure water, shaken evenly for more than 2 minutes, and soaked for about 2-5 hours to drain the inorganic acid. The above operation is repeated 2-6 times.

4. The method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals according to claim 1, characterized in that: In step (3), the fluorine-containing resin material is impregnated with an organic solvent in a ratio of 4:5 to 2:

5.

5. The method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals according to claim 4, characterized in that: In step (3), the organic solvent is a mixed solvent of propanol and ethanol, and the volume ratio of propanol to ethanol is 1:

1.

6. The method for purifying fluorine-containing resin materials for semiconductor-grade electronic chemicals according to claim 1, characterized in that: In step (4), the fluorine-containing resin is immersed in an inorganic acid with a metal ion content of ≤10 ng / kg at a ratio of 1:60 to 1:80, and heated and stirred. Samples are taken at intervals of 24 h, 48 h, and 72 h to analyze the precipitation of metal ions. When the metal ions in the solution no longer increase, the immersion is terminated.

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