A second-stage purification device and purification process for ultrapure water

Abstract

A second-order purification device and purification process for ultrapure water. The device includes a first-order system and a second-order system connected in sequence. The first-order system treats primary pure water to obtain secondary pure water, including a desalination unit, a first hybrid photolysis absorber, and a degassing unit. The second-order system treats secondary pure water to obtain ultrapure water, including a membrane absorber, a second hybrid photolysis absorber, and a degassing ultrafiltration unit. The first hybrid photolysis absorber has a first photolysis zone and a first treatment zone downstream thereof, and the radiation dose in the first photolysis zone is 300-800 mJ / cm<supgt;2< / supgt>. The membrane absorber includes a hydrogen dissolution membrane and a hydrogen supply pipeline, and provides hydrogenated water for the second hybrid photolysis absorber downstream. The second hybrid photolysis absorber has a second photolysis zone and a second treatment zone downstream thereof, and the radiation dose in the second photolysis zone is 200-900 mJ / cm<supgt;2< / supgt>. The present invention effectively realizes the comprehensive control of various indexes of ultrapure water, and provides guarantee for the nano-semiconductor manufacturing process and processing quality.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing ultrapure water for cleaning integrated circuits, and in particular to a second-stage purification device and a purification process for ultrapure water. Background Art

[0002] Ultrapure water is an important guarantee for the manufacturing process and processing quality of nano-semiconductors. It is mainly used for product cleaning, liquid dilution and other links in the semiconductor production process. In recent years, with the reduction of semiconductor device process nodes, its production process water has put forward extremely high requirements for trace metals, total organic carbon (TOC), total silicon, microparticles and dissolved oxygen (DO). It has become an urgent need to develop advanced ultrapure water preparation technology to meet the water quality requirements of semiconductor cutting-edge process water, realize the joint reduction of multiple pollutants, and achieve comprehensive control of trace metals, TOC, boron (B), DO, H2O2 and other indicators.

[0003] Invention patent CN115636557B discloses a method for preparing cleaning water for nano-process integrated circuits. In this method, primary pure water is subjected to deep desalination treatment, and the primary pure water is passed through a first mixed photolysis absorber to degrade total organic carbon and remove weakly ionized impurities, and then oxygen is removed through a first vacuum membrane degassing device to form secondary pure water; the secondary pure water is polished, and the secondary pure water is passed through a catalytic mixed photolysis absorber to remove trace metal ions, weakly ionized impurities and low molecular weight organic matter to ppq level, ppt level and ppb level respectively, and at the same time, the free radical composite oxidant is controlled at sub-ppb level.

[0004] Invention patent CN115626745B discloses a purification device and method for cleaning water for advanced chip manufacturing. In the purification device, at least one first shell is a transparent, heat-insulating, hollow closed structure; at least one radiation light source is arranged in the hollow closed structure to form a vacuum radiation chamber; the water to be purified enters the first reaction chamber from the lower supporting orifice plate and flows out from the outflow hole on the upper part of the second shell to form a water flow channel, and the water flow channel at least partially overlaps the photolysis zone to photocatalytically oxidize the water to be purified to form a first treated water; the first treated water from the sealed chamber is sequentially removed from carboxylic acid small molecule organic matter and carbonic acid in the positive adsorption zone, quenched free radical complex oxidant in the catalytic reaction zone, and reduced trace metals, non-metallic ions, weakly ionized inorganic salts, and soluble low-molecular organic matter in the ion polishing zone to form cleaning water for advanced chip manufacturing.

[0005] Although the above invention provides a new full-process treatment solution for ultrapure water preparation in the field of high-end nano-integrated circuit manufacturing, in some applications with more stringent requirements, the byproduct O2 produced by the hybrid photolysis absorber or purification device increases the micro-contamination of dissolved gases in the water, and increases the load and risk of DO control in the key process section of ultrapure water below 7 nm. On the other hand, the surface of nanoparticles is also prone to form an oxide layer or oxide film due to the dissociation and release of O2, which reduces the decomposition efficiency. In the deep desalination section, the boron adsorbent in the hybrid photolysis absorber is also susceptible to the inhibition and competition of the organic acid produced by photolysis on its adsorption of boric acid, thereby affecting the adsorption efficiency of boron.

[0006] Therefore, how to improve the existing ultrapure water purification equipment, effectively control the dissolved oxygen content and improve the removal efficiency of trace boron in the ultrapure water preparation process, and avoid the secondary pollution of water quality by the by-products produced by the mixed photolysis absorber, so as to achieve comprehensive control of trace metals, TOC, boron (B), DO, H2O2 and other indicators, has become a problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0007] In view of the defects existing in the above-mentioned prior art, the present invention provides a second-stage purification equipment and purification process for ultrapure water. Through the improved design of ultrapure water purification equipment and process flow, the comprehensive control of trace metals, TOC, boron (B), DO, H2O2 and other indicators is effectively achieved, providing guarantee for the nano-semiconductor manufacturing process and processing quality.

[0008] In a first aspect, the present invention provides a second-order purification device for ultrapure water, comprising a first-order system and a second-order system connected in sequence;

[0009] The first-stage system processes primary pure water to obtain secondary pure water, including a desalination unit, a first hybrid photolysis absorber, and a degassing unit;

[0010] The second-stage system processes the secondary pure water to obtain ultrapure water, including a membrane absorber, a second hybrid photolysis absorber and a degassing ultrafiltration unit;

[0011] The first hybrid photolysis absorber has a first photolysis zone and a first treatment zone downstream thereof. In the direction of water flow, the first treatment zone includes a positive adsorption layer, a complex reaction layer and an ion polishing layer in sequence. The thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is (1-4): (1-12): (1-6); the radiation dose of the first photolysis zone is 300-800 mJ / cm 2 ;

[0012] The membrane absorber includes a hydrogen dissolving membrane and a hydrogen supply pipeline, which provides hydrogen-filled water for the downstream second hybrid photolysis absorber;

[0013] The second hybrid photolysis absorber has a second photolysis zone and a second treatment zone downstream thereof. In the direction of water flow, the second treatment zone includes a catalytic reaction layer and an ion polishing layer in sequence. The thickness ratio of the catalytic reaction layer to the ion polishing layer is 1: (1-50); the radiation dose of the second photolysis zone is 200-900mJ / cm 2 .

[0014] Preferably, in the first treatment zone, the positively charged adsorption layer includes a positively charged adsorbent, which is a positively charged adsorption resin with a quaternary ammonium functional group or a mixed resin mixed with a positively charged adsorption resin with a quaternary ammonium functional group; the complex reaction layer includes a boron absorbent; and the ion polishing layer includes a mixed ion exchanger with a basic group and an acidic group respectively;

[0015] The thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is (1-4): (8-10): (1-4).

[0016] In the second treatment zone, the catalytic reaction layer includes a supported metal nanoparticle catalyst; and the ion polishing layer includes a mixed ion exchanger having a basic group and an acidic group respectively.

[0017] The thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:(1.2-50), more preferably 1:(2.5-20).

[0018] Compared with previous water purification devices, especially hybrid photolysis absorbers, the present invention has studied and explored a more efficient and stable combination of a first hybrid photolysis absorber and a second hybrid photolysis absorber and their internal filling method and filling thickness design.

[0019] In addition, the acquisition of primary pure water can refer to the method provided by the previous invention patent CN115636557B, and the raw water can be subjected to a series of treatments. Other methods that can obtain primary pure water can also be used.

[0020] The positively charged adsorbent is a strong adsorbent having or mixed with a quaternary ammonium functional group and having a positive charge. One method of preparing this absorbent is to react a chloromethylated polystyrene cross-linked resin skeleton with dimethylbenzene, trimethylamine and other main raw materials through suspension polymerization, chloromethylation and amination. Preferably, a trimethylbenzyl ammonium-based gel-type divinylbenzene cross-linked adsorbent or a mixed resin mixed with this adsorbent is selected, which has a stronger adsorption function for anionic electrolytes in water, especially small molecular organic matter. Further preferably, a high-purity model of this type of adsorbent is selected to ensure and meet the strict requirement of TOC mass concentration ≤1μg / l, preferably ≤0.5μg / l.

[0021] The boron absorbent is a monodisperse porous absorbent, including methylamine-based granular beads or chelating resins. The boron absorbent can be made by grafting aliphatic polyols or aromatic polyhydroxyphenols onto a polymer skeleton; preferably, the porous hydrophobic polymer skeleton is not easy to infiltrate, affecting mass transfer, and the crosslinking agent divinylbenzene in the skeleton contains multiple isomers, which significantly affects the performance of the polymer structure. Glyceryl methacrylate (GMA, chemical formula C7H) with strong hydrophilicity and increased average pore size after grafting is used. 10 O3) and ethylene glycol dimethacrylate (EDM, chemical formula C 10 H 14 O4) is used as the skeleton matrix, and NMDG is grafted on the macroporous particle skeleton of the copolymer dissolved in dimethyl sulfoxide solution to prepare the efficient boron absorbent GMA-EDM-NMDG; further preferably, a dimethylformamide deionized water mixture is used to enhance the resin swelling to increase the pore size and functional group density, and a porous chloromethyl polystyrene cross-linked resin that can provide more active sites for adsorption after cross-linking and has better structure and mechanical properties is used as the polymer skeleton carrier (CMPS), and a more stretchy polyhydroxy fatty long-chain polyol is used as the functional monomer, and a one-step adsorption method is used, stirring, eluting, and drying to obtain a monodisperse porous resin boron absorbent containing ortho- and meta-dihydroxy functional groups.

[0022] The mixed ion exchanger of the ion polishing layer preferably uses two ion exchangers with alkaline and acidic groups respectively, which are pre-mixed in a certain proportion. It is more preferably a high-purity mixed ion exchanger with a dissolution concentration ΔTOC ≤ 1 μg / l, a leakage concentration Metals ≤ 0.1 ng / l and is non-regenerable.

[0023] The metal catalyst is preferably a multiphase metal catalyst that directly bonds with a copolymer skeleton such as styrene and acrylic acid to form a polymer complex using a transition metal as a complex; more preferably, a UP-grade palladium-loaded resin or platinum-loaded resin prepared by dispersing precious metal nanoparticles such as Pd or Pt on the surface of a dimethylhydroxyethylbenzylammonium polymer carrier phase; further, a macroporous high specific surface area polystyrene-divinylbenzene cross-linked polymer functionalized with a trimethylamine quaternary ammonium group is used as a solid phase carrier, and a static adsorption method and a one-step reduction method are used to complex a heterogeneous platinum group metal by a coordinated covalent bond. (Palladium, platinum, ruthenium, rhodium, osmium, iridium) ion precursors, and reduced transformation to form a heterogeneous gel-type or macroporous resin matrix catalyst, typically, such as: gel-type polystyrene-loaded nano-palladium metal catalyst; also optionally, using amine-functionalized PS microspheres as polymer carriers, applying the heterogeneous condensation method based on the principle of thermodynamics, using liquid bimetallic solution as precursor salt, adding stabilizers and reducing agents to synthesize nanoparticle dispersions, and mixing with the PS microsphere dispersion, stirring, filtering, and drying, thereby obtaining a nano alloy composite particle catalyst.

[0024] The study found that under optimal alkaline conditions, the electron donors on the surface of metal nanoparticles can be converted into •OH - Through chain branching and transfer, a variety of oxygen free radicals are generated, which jointly promote the chain reaction kinetics process, thereby accelerating the consumption and decomposition of H2O2 in the aqueous phase, and generating oxygen at the same time. The thermochemical equation is expressed as:

[0025] H2O2 (l)=H2O(l)+1 / 2O2 (g) ΔH=-105.8 kJ / mol

[0026] Preferably, the first hybrid photodecomposer and the second hybrid photodecomposer have the same structure, including:

[0027] A first shell and at least one radiation light source, wherein the radiation light source is encapsulated in a transparent hollow closed structure formed by the first shell to form a vacuum radiation chamber;

[0028] A second shell is arranged around the first shell, the second shell and the lower supporting orifice plate at the bottom and the connecting cover at the top form a photolysis zone, and the lower supporting orifice plate is provided with an inlet pipe;

[0029] The top cover, the third shell and the bottom wall are sealed and connected in sequence, an upper orifice plate is arranged around the second shell at the upper part of the inner cavity of the third shell, and a lower orifice plate is arranged around the second shell at the lower part of the inner cavity, and a processing area is formed between the upper orifice plate and the third orifice plate;

[0030] The top cover is sealed and fixed to the connecting cover of the second shell, and a sealed cavity is formed between the top cover and the upper orifice plate, and the second shell has an outflow hole in the sealed cavity;

[0031] A water collecting chamber is formed between the bottom wall and the lower orifice plate, and a through hole and an outflow port for sealing and fixing the inlet pipe are provided on the bottom wall;

[0032] The water to be purified enters the photolysis zone from the inlet pipe, enters the sealed chamber from bottom to top through the outflow hole, then passes through the upper orifice plate, the treatment zone, and the lower orifice plate from top to bottom to enter the water collecting chamber, and enters the degassing unit from the outflow port;

[0033] In the first hybrid photolysis absorber, the first treatment zone is provided with the positive adsorption layer, the complex reaction layer and the ion polishing layer from top to bottom;

[0034] In the second hybrid photolysis absorber, the catalytic reaction layer and the ion polishing layer are arranged from top to bottom in the second treatment zone.

[0035] The first hybrid photolysis absorber and the second hybrid photolysis absorber are preferably cylindrical in shape as a whole, and are formed by surrounding a plurality of coaxial cylindrical shells with different radii. Among them, the cylindrical first shell forms a transparent hollow closed structure, and the first shell is made of high-purity transparent quartz with a hydroxyl content of ≤5μg / g, and the transmittance is greater than 90%, which can prevent the treated water from taking away the heat of the light source, so that the temperature in the vacuum radiation cavity is not too low to affect the luminous efficiency, and its heat preservation effect also plays a role in stabilizing the output of ultraviolet light, so that the water temperature changes between 5-32°C and has almost no effect on the output intensity of the discharge light source. The cylindrical second shell includes a low-transmittance quartz layer, and a vacuum-evaporated metal film or a VUV hardened metal film on the outer surface of the low-transmittance quartz layer, which avoids the reflection loss of multiple interfaces caused by Fresnel reflection, and can more effectively improve the reflectivity. The cylindrical third shell or its inner surface is made of thermoplastic resin material polymerized by ethylene or propylene, or fiber-reinforced composite plastic.

[0036] Preferably, in the first-order system, the desalination unit includes at least one of a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower; the degassing unit includes a membrane contact degassing device;

[0037] In the second-order system, the membrane absorber is used to dissolve hydrogen into the secondary pure water to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l; the degassing ultrafiltration unit includes a membrane contact degassing device and an ultrafiltration device. In addition, booster pumps, metering pumps, sampling points and other components can be set between the units or devices of the first-order system and the second-order system as needed. Preferably, a booster pump is also set between the membrane contact degassing device and the ultrafiltration device.

[0038] The present invention has a built-in hydrogen-dissolving membrane in the membrane absorber of the second-order system, which is arranged upstream of the second hybrid photolysis absorber. By means of hydrogen pressure introduction, high-purity hydrogen can be evenly transferred to water to achieve liquid phase absorption of gas. Preferably, the flow path is connected in a mixed flow ratio adjustment manner, mixed with the water outlet of the pure water storage tank, and the mixed water to be purified enters the second hybrid photolysis absorber. When the hydrogen-filled water flows through the catalytic reaction layer of the second hybrid photolysis absorber, hydrogen peroxide will decompose on the catalyst surface to produce oxygen (refer to the aforementioned thermochemical equation). Since the water is rich in hydrogen, hydrogen will be adsorbed to the catalyst surface, and the adsorbed atomic oxygen will preferably be hydrogenated to adsorbed hydroxyl groups at the active sites on the catalyst surface, and the adsorbed hydroxyl groups will further hydrogenate to water, and the product water will desorb from the catalyst surface. The oxidation reaction of hydrogen under the catalyst framework is also effective for removing dissolved oxygen in water. This measure also effectively solves the problems of surface oxidation, performance degradation, and shortened life of the catalyst after long-term use, and avoids the limited recovery steps such as interruption of operation, extraction, soaking, and cleaning, as well as the pollution risks brought about. In order to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l, the aforementioned mixing ratio is 3-10%.

[0039] Preferably, the second-stage purification equipment further includes an online detection unit and a control unit, the online detection unit includes a first sampling tube arranged at the water outlet of the degassing unit, a second sampling tube arranged at the water outlet of the degassing ultrafiltration unit, and a detection device connecting the first sampling tube and the second sampling tube, and the control unit determines the connection mode of the water outlet of the degassing unit and the water outlet of the degassing ultrafiltration unit according to the detection result of the detection device, including:

[0040] The water outlet of the degassing unit is controlled to be connected to the pure water storage tank between the first-order system and the second-order system, and / or connected to the water inlet of the desalination unit through the first reflux pipeline;

[0041] The water outlet of the degassing ultrafiltration unit is controllably connected to the ultrapure water supply network, and / or is connected to the pure water storage tank through a second reflux line.

[0042] More preferably, the first reflux line comprises a first auxiliary reflux pipe, which is controllably connected to an inlet of a shallow desalination system upstream of the first-stage system; and / or

[0043] The second return pipeline includes a second auxiliary return pipe, which is controllably connected to the water inlet of the desalination unit of the first-stage system, and / or is controllably connected to the inlet of the shallow desalination system upstream of the first-stage system.

[0044] Based on the setting of the first reflux pipeline and the second reflux pipeline, the present invention further refines the reflux pipeline, and adds at least one first auxiliary reflux pipe and at least one second auxiliary reflux pipe, which can be opened or closed according to the instructions of the control unit, especially according to the reflux instructions of the control unit to adjust the ratio of each reflux diversion.

[0045] Specifically, when the conventional system is running, there may be no water reflux in the first auxiliary reflux pipe, and the secondary pure water at the outlet of the degassing unit is refluxed in a certain proportion by the first reflux pipeline to the water inlet of the first-stage system desalination unit for another first-stage purification treatment; when the test results show that the water quality is poor or in the system trial operation stage, in order to quickly optimize the water quality, when the system determines that reflux is suitable, the secondary pure water refluxed in the first reflux pipe passes through the first auxiliary reflux pipe in a short time, and at least partially or completely refluxes to the inlet of the shallow desalination system upstream of the first-stage system for another shallow desalination pretreatment.

[0046] Similarly, there may be no reflux water in the second auxiliary reflux pipe when the water quality is normal. However, when the quality of ultrapure water is significantly reduced, or in order to quickly optimize the water quality during the system trial operation stage, the second-order system, on the basis of ensuring stable water output, uses at least one second auxiliary reflux pipe to connect the water inlet of the desalination unit to perform a first-order purification treatment again, and / or connect the shallow desalination system inlet upstream of the first-order system to perform a shallow desalination pretreatment again. It corresponds to trial operation, before the water quality meets the standard, closing the outlet valve for self-circulation within the station, and other usage scenarios; in the production state, only when the secondary pure water is unqualified due to the excessive primary pure water and does not affect the process water consumption, it can be partially switched to the second auxiliary reflux pipe, and only supply the first-order system and its upstream makeup water.

[0047] Furthermore, in order to obtain qualified primary pure water, the water to be purified has been desalted at least once in the shallow desalination system (or pre-desalination system), preferably twice in the multiple bed and reverse osmosis process. Therefore, the farthest reflux position of the first auxiliary return pipe and the second auxiliary return pipe does not need to extend to the raw water tank, but can be at the entrance of the shallow desalination system, and enters the desalted water tank (DI water tank) of the shallow desalination system together with the upstream pre-treated water for treatment to obtain high-quality primary pure water.

[0048] Preferably, the detection device includes at least one of a plasma mass spectrometer, an ion chromatograph, a total organic carbon analyzer, a dissolved oxygen analyzer, a microparticle analyzer, a boron analyzer, a silica analyzer, a resistivity meter, and a hydrogen peroxide analyzer. There are many water quality detection methods and indicators, and the above detection devices are not exhaustive, and can be selected or increased or decreased according to actual water use requirements.

[0049] The online detection unit of the present invention monitors the water quality in real time and adjusts the first-order return water and second-order return water distribution mode through the control unit:

[0050] In the default state where the second-stage return water returns to the pure water storage tank, when the water quality test value of the second-stage treatment is poor, the second-stage return water can be partially / fully returned to the water inlet of the desalination unit of the first-stage treatment or the inlet of the shallow desalination system upstream of the first-stage system;

[0051] In the default state where the first-order return water returns to the water inlet of the desalination unit, when the water quality test value of the first-order treatment is poor, the first-order return water can be partially / fully returned to the inlet of the shallow desalination system upstream of the first-order system; or when the water quality test value of the first-order treatment is poor due to excessive pure water, the second-order return water can be partially returned to the first-order system and its upstream to replenish the first-order system without affecting the process water consumption.

[0052] The default circulation mode is controlled and adjusted by the liquid level of the pure water storage tank and the process water consumption respectively. The above two situations are to determine the return water direction according to the changes in water quality (obvious water quality deterioration, water quality decline caused by upstream pollution or trial operation stage, etc.), which is not a normal circulation mode, and therefore basically does not constitute a switching burden on the system and control unit.

[0053] The present invention, through the arrangement of an online detection unit, a control unit, a first reflux pipeline (and its first auxiliary reflux pipe) and a second reflux pipeline (and its second auxiliary reflux pipe), can, on the one hand, monitor the water quality of the first-order system and the second-order system in real time and stably provide high-quality semiconductor cutting-edge process water; on the other hand, through the regulation of the volume of the pure water storage tank and the reflux ratio, it is convenient to control the actual water output of the first-order system and the second-order system, especially to provide a quantitative and continuously stable ultrapure water flow for the semiconductor process downstream of the second-order system; in addition, through the water quality monitoring and reflux of the first-order system and the second-order system, it is possible to accurately grasp the purification conditions of the water flow at each stage, match the corresponding radiation doses in the first photolysis zone and the second photolysis zone, and complete the purification work of each order system in an energy-saving and efficient manner.

[0054] Preferably, the first photolysis zone and the second photolysis zone include a radiation light source, which includes a VUV / UV low-pressure high-intensity mercury vapor or a low-pressure high-intensity amalgam arc discharge light source. The radiation light source is connected to the control unit, and the control unit adjusts the radiation dose of the radiation light source according to the parameters of the water flow to be purified.

[0055] Wherein, the first photolysis zone and the second photolysis zone preferably include several 185nm radiation light sources, such as 1-48 radiation light sources, preferably 20-40 radiation light sources, and the illumination and irradiation time of each radiation light source are independently adjustable, so that the number of radiation light sources to be turned on and off can be selected according to the actual water purification amount and water purification requirements, thereby regulating the overall radiation dose. The radiation light source can provide high-intensity radiation and sufficient water treatment dose. Since the radiation light source itself has high manufacturing and operating costs and basically needs to be replaced in about one year, the present invention regulates the illumination and irradiation time of the radiation light source according to the actual water consumption and water quality requirements, thereby better reducing the operation and replacement costs. Optionally, when multiple radiation light sources are used, the radiation light sources can be grouped and controlled, for example, they can be divided into 2-8 groups, each group of about 1-6 radiation light sources, so that the radiation light source groups rotate to work.

[0056] The second aspect of the present invention also provides a purification process using the second-stage purification device, comprising the following steps:

[0057] S1. Perform a first-stage purification process in a first-stage system to obtain secondary pure water from primary pure water, including:

[0058] S1.1 The pure water after shallow desalination pretreatment enters the desalination unit to further remove anions and cations to obtain deep desalted water;

[0059] S1.2 Deep desalted water enters the first mixed photolysis absorber and undergoes photolysis treatment, positive adsorption treatment, complexation reaction treatment and ion polishing treatment in sequence to obtain quasi-secondary pure water;

[0060] S1.3 Quasi-secondary pure water enters the degassing unit to remove dissolved gases and volatiles, obtains secondary pure water, and enters the pure water storage tank;

[0061] S2, performing a second-stage purification process in a second-stage system to obtain ultrapure water by treating the secondary pure water, comprising:

[0062] S2.1 Secondary pure water is output from the pure water storage tank and enters the membrane absorber. Hydrogen with a purity greater than 99.9% is introduced into the membrane absorber to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l;

[0063] S2.2 The hydrogen-filled water enters the second hybrid photolysis absorber and undergoes photolysis treatment, catalytic reaction treatment and ion polishing treatment in sequence to obtain quasi-ultrapure water;

[0064] S2.3 Quasi-ultrapure water enters the degassing ultrafiltration unit to remove dissolved gases, volatiles and microparticles to obtain ultrapure water.

[0065] The purification process of the present invention performs shallow desalination pretreatment on raw water through a pretreatment system to obtain primary pure water, and the water quality characteristics of the primary pure water meet TOC < 50μg / L, conductivity < 2μS / cm, boron (B) < 10μg / L, DO < 10 mg / L. The primary pure water enters the first-order system, passes through the desalination unit, deeply removes anions and cations in the water, and removes a small amount of TOC. Through the three-layer treatment agent (positive adsorption layer, complex reaction layer and ion polishing layer, stacked from top to bottom) loaded in the first mixed photolysis absorber, low molecular organic matter (LMWOM) can be degraded, weakly ionized impurities are further removed, and the resistivity is not reduced by pollution. Specifically, the positively charged adsorbent in the positive adsorption layer can efficiently adsorb low molecular weight acidic organic matter (LMW CAs) produced by 185nm UV oxidation of LMWOM, and then undergo a complexation reaction with the boron absorbent in the complexation reaction layer to achieve a deep boron removal effect. The ion exchanger in the ion polishing layer can remove the micro-polluted electrolyte released by the NMDG-based absorbent, inhibit the decrease in resistivity, and control the increased TOC concentration to 1μg / L or even lower, which comprehensively improves the quality of produced water. Subsequently, the dissolved oxygen (including dissolved gases, volatile substances, etc.) in the water and the resin is removed by the degassing unit to form secondary pure water.

[0066] The secondary pure water is then catalyzed and polished by the second-order system. The secondary pure water first passes through a membrane absorber (Membrane Gas Absorber, MGA), where high-purity H2 is dissolved using a hydrogen-dissolving membrane. It then passes through a second hybrid photolysis absorber filled with a two-layer treatment agent (a catalytic reaction layer and an ion polishing layer, stacked from top to bottom) to further deeply remove, absorb and degrade trace metal ions, dissolved oxygen, weakly ionized impurities and low-molecular organic matter, and treat them to extremely low limit values ​​of ppq, ppt and ppb levels respectively; at the same time, the free radical complex oxidant (H2O2) produced in the catalytic photolysis process can be controlled at the sub-ppb level (as low as below 1ug / L). Specifically, since the metal catalyst of the catalytic reaction layer adopts a supported metal catalyst, the catalyst matrix itself can be a positively charged adsorbent, which can efficiently adsorb low molecular weight acidic organic matter (LMW CAs) produced by 185nm UV oxidation of LMWOM, and can decompose H2O2 to make H2O2 <1μg / L, preferably <0.8μg / L. The decomposition byproduct O2 can also be reduced to H2O under the action of H2. A proper amount of H2 can also catalytically reduce O2 in water to H2O on the surface of the supported metal catalyst matrix. The ion exchanger of the ion polishing layer can further remove trace metals and increase resistivity. Finally, the membrane degassing and ultrafiltration treatment of the degassing ultrafiltration unit can achieve polishing removal of dissolved gases and microparticles.

[0067] Preferably, in step S1.3, the outlet water of the degassing unit is sampled for the first time and tested online, and the control unit determines, based on the online test result, that the outlet of the degassing unit is connected to the pure water storage tank to enter the second-order purification treatment, that the inlet of the desalination unit is connected to the water inlet of the desalination unit to perform the first-order purification treatment again, and / or that the inlet of the shallow desalination system upstream of the first-order system is connected to perform the shallow desalination pretreatment again;

[0068] In step S2.3, the outlet water of the degassing ultrafiltration unit is sampled for a second time and tested online, and the control unit determines, based on the online test results, that the outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network, connected to the pure water storage tank for a second-order purification treatment, connected to the water inlet of the desalination unit for a first-order purification treatment, and / or connected to the inlet of the shallow desalination system upstream of the first-order system for a shallow desalination pretreatment.

[0069] When the conventional system is in operation, the first reflux ratio of the first reflux line is above 5%, preferably 9-90%. The first reflux ratio is the ratio of the reflux water volume of the first reflux line to the water volume entering the pure water storage tank from the water outlet of the degassing unit per unit time. When the water quality is seriously degraded, the first auxiliary reflux pipe can be opened to reflux part or all of the reflux water to further upstream through the first auxiliary reflux pipe in a short time.

[0070] Different from the first reflux ratio, due to the need to pay close attention to the downstream water consumption, the second reflux ratio of the second reflux line is set as the ratio of the reflux water volume of the second reflux line per unit time to the downstream water consumption. Usually, the second reflux ratio is set at 20-80%, preferably 25-50%. Similarly, when the conventional system is running, the second auxiliary reflux pipe can be closed. When the quality of ultrapure water deteriorates significantly, or the quality of secondary pure water is significantly reduced due to the excessive quality of primary pure water, or during the system trial operation stage, when the process water consumption is not affected, part of the reflux water or all of the reflux water will be refluxed to the upstream through the second auxiliary reflux pipe in a short time.

[0071] Specifically, a number of flow detectors are set in the first mixed photolysis absorber, the second mixed photolysis absorber or other required places to feed back the amount of water to be treated in the first photolysis zone and the second photolysis zone and the flow conditions of the area that needs to be paid close attention to to the control unit in real time. The control unit determines the total illumination and irradiation time of the radiation light sources in the first photolysis zone and the second photolysis zone according to the online detection results and the feedback results of the flow detector, and compares the set water quality threshold and the current radiation conditions, so as to determine the specific conditions such as the number of radiation light sources turned on. Taking the maximum illumination of all radiation light sources turned on as 100%, the illumination adjustment range of the first photolysis zone and the second photolysis zone is between about 10-100%, preferably between 30-100%. In addition, the radiation light sources can be grouped and controlled, for example, they are divided into 2-8 groups, each group has about 1-6 radiation light sources, so that the radiation light source groups work in rotation. More preferably, they are divided into 4-8 groups, each group has about 1-5 radiation light sources, increasing the number of radiation light source groups and reducing the number of radiation light sources in a single group, so that the radiation dose can be more accurately controlled. The radiation dose in the first photolysis zone is 300-800 mJ / cm 2 The radiation dose in the second photolysis zone is 200-900mJ / cm 2 .

[0072] Preferably, the control unit adjusts the radiation dose of the first photolysis zone and the radiation light source of the first photolysis zone respectively according to the parameters of the water flow to be purified; and / or

[0073] Determine the connection mode of the water outlet of the degassing unit according to the online detection result of the first sampling; and / or

[0074] According to the online detection result of the second sampling, the connection mode of the water outlet of the degassing ultrafiltration unit is determined;

[0075] The quality of ultrapure water provided to the ultrapure water supply network reaches:

[0076] Trace metals <0.05ng / L, TOC <0.5μg / L, DO <0.3μg / L, B <0.5ng / L, H2O2 <1μg / L, concentration of particles larger than 0.05μm <0.1pcs / mL.

[0077] The present invention has at least the following beneficial effects:

[0078] (1) The present invention adopts a second-order purification device and process, and the first-order system processes the primary pure water to obtain the secondary pure water, and the second-order system processes the secondary pure water to obtain ultrapure water and outputs it stably. Among them, the first hybrid photolysis absorber integrates the multiple reaction mechanisms of photolysis treatment, positive adsorption, complexation reaction, and ion polishing, and the second hybrid photolysis absorber integrates the multiple reaction mechanisms of photolysis treatment, metal catalysis, and ion polishing. In particular, the first hybrid photolysis absorber and the second hybrid photolysis absorber respectively integrate the functions of multiple existing treatment equipment, which can shorten the pipeline path of the existing equipment and effectively reduce the concentration of micro-pollution dissolved in the pipeline during the treatment process. In addition, the hybrid photolysis absorber preferably adopts a non-metallic design to minimize trace metal micro-pollution, which promotes the innovation and progress of key processes and equipment in the ultrapure water preparation system.

[0079] (2) The purification equipment and process system of the present invention can meet the water quality requirements of semiconductor cutting-edge process water, and provide advanced ultrapure water purification technology for deep removal of multiple pollutants. It can obtain lower total organic carbon, boron, trace metals and dissolved oxygen and other ultrapure water purification water quality indicators, meet the higher standard requirements of nano-process semiconductors for ultrapure water, and further refine the design of the hybrid photolysis absorber, solving the problems of the previous polishing section hybrid photolysis absorber producing oxygen byproducts and the deep desalination section hybrid photolysis absorber affecting the boron removal efficiency.

[0080] (3) The control unit, online detection unit, first reflux pipeline (including its first auxiliary reflux pipeline) and second reflux pipeline (including its second auxiliary reflux pipeline) of the present invention can, on the one hand, monitor the water quality of the first-order system and the second-order system in real time and stably provide high-quality semiconductor cutting-edge process water; on the other hand, by regulating the volume of the pure water storage tank and the reflux ratio, it is convenient to control the actual water output of the first-order system and the second-order system, especially to provide a quantitative and continuous and stable ultrapure water flow for the semiconductor process downstream of the second-order system; in addition, by monitoring the water quality of the first-order system and the second-order system, regulating the first-order and second-order reflux and its auxiliary reflux, and the radiation dose of the photolysis zone, it is possible to accurately grasp the purification status of each stage of the water flow and complete the purification work of each order system in an energy-saving and efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 It is a schematic diagram of the structure of the first hybrid photodecomposition absorber and the second hybrid photodecomposition absorber of the present invention;

[0082] Figure 2 It is a purification process flow chart of the present invention.

[0083] Figure markings: 10-shallow desalination system, 11-desalination unit, 12-first mixed photolysis absorber, 121-first photolysis zone, 122-first treatment zone, 1221-positive adsorption layer, 1222-complexation reaction layer, 1223-first ion polishing layer, 13-degassing unit, 21-membrane absorber, 22-second mixed photolysis absorber, 221-second photolysis zone, 222-second treatment zone, 2221-catalytic reaction layer, 2222-second ion polishing layer, 23-second-order membrane contact degassing device, 24-ultrafiltration device. DETAILED DESCRIPTION

[0084] In order to better understand the above technical solution, the above technical solution will be described in detail below in combination with the specification and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0085] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0086] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0087] like Figure 1 and Figure 2 As shown, the present invention provides a second-order purification device and purification process for ultrapure water. Specifically, the second-order purification device includes a first-order system and a second-order system connected in sequence, wherein:

[0088] (1) First-order system:

[0089] The primary pure water is treated to obtain secondary pure water, including a desalination unit 11, a first mixed photolysis absorber 12 and a degassing unit 13 which are connected in sequence, specifically:

[0090] (1.1) A desalination unit 11, comprising at least one of a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower;

[0091] (1.2) The first hybrid photolysis absorber 12, see the attached Figure 1 , having a first photolysis zone 121 and a first treatment zone 122 downstream thereof, wherein in the direction of water flow, the first treatment zone 122 sequentially comprises a positive adsorption layer 1221, a complex reaction layer 1222 and a first ion polishing layer 1223, and the thickness ratio of the positive adsorption layer 1221, the complex reaction layer 1222 and the first ion polishing layer 1223 is (1-4): (1-12): (1-6), preferably (1-4): (8-10): (1-4);

[0092] In the first treatment area 122, the positively charged adsorption layer 1221 includes a positively charged adsorbent, and the positively charged adsorbent is a positively charged adsorption resin with a quaternary ammonium functional group or a mixed resin mixed with a positively charged adsorption resin with a quaternary ammonium functional group;

[0093] The complex reaction layer 1222 includes a boron absorber;

[0094] The ion polishing layer 1223 includes a mixed ion exchanger having basic groups and acidic groups respectively;

[0095] The radiation dose of the first photolysis zone 121 is 300-800 mJ / cm 2 , the TOC mass concentration of the water at the outlet of the first mixed photolysis absorber 12 is below 3μg / l, preferably less than 2μg / l; the first photolysis zone 121 includes a plurality of 185nm radiation light sources, such as 1-25 radiation light sources, preferably 4-20 radiation light sources, and the illumination and irradiation time of each radiation light source are independently adjustable, so that the number of radiation light sources can be selected to be turned on and off according to the actual water purification volume and water purification requirements, thereby regulating the overall radiation dose. When multiple radiation light sources are used, the radiation light sources can be controlled in groups, for example, they can be divided into 2-8 groups, each group of about 1-6 radiation light sources, so that the radiation light source groups can work in rotation.

[0096] (1.3) The degassing unit 13 includes a membrane contact degassing device, which removes oxygen and carbon dioxide produced by TOC oxidation to form secondary pure water, which is sent to a pure water storage tank.

[0097] (2) Second-order system:

[0098] The secondary pure water is treated to obtain ultrapure water, including a membrane absorber 21, a second hybrid photolysis absorber 22 and a degassing ultrafiltration unit connected in sequence, specifically:

[0099] (2.1) A membrane absorber 21, comprising a hydrogen dissolving membrane and a hydrogen supply pipeline, for dissolving hydrogen into the secondary pure water to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l;

[0100] (2.2) The second hybrid photolysis absorber 22, see Figure 1 , having a second photolysis zone 221 and a second treatment zone 222 downstream thereof, in the direction of water flow, the second treatment zone 222 sequentially comprises a catalytic reaction layer 2221 and a second ion polishing layer 2222, the thickness ratio of the catalytic reaction layer 2221 to the second ion polishing layer 2222 is 1: (1-50), preferably 1: (1.2-50), more preferably 1: (2.5-20);

[0101] The radiation dose of the second photolysis zone 221 is 200-900 mJ / cm 2 , the TOC mass concentration of the water at the outlet of the second mixed photolysis absorber 22 is below 0.5μg / l, preferably below 0.3μg / l; the second photolysis zone 221 has several 185nm radiation light sources, such as 1-25 radiation light sources, preferably 4-20 radiation light sources, and the illumination and irradiation time of each radiation light source are independently adjustable, so that the number of radiation light sources to be turned on and off can be selected according to the actual water purification volume and water purification requirements, thereby regulating the overall radiation dose. When multiple radiation light sources are used, the radiation light sources can be controlled in groups, for example, they can be divided into 2-8 groups, each group of about 1-6 radiation light sources, so that the radiation light source groups work in rotation. More preferably, it is divided into 4-8 groups, each group of about 1-4 radiation light sources, increasing the number of radiation light source groups and reducing the number of radiation light sources in a single group, which can more accurately regulate the radiation dose.

[0102] (2.3) A degassing ultrafiltration unit, comprising a membrane contact degassing device 23 and an ultrafiltration device 24 connected in sequence, to remove dissolved gases and microparticles in the residual water to sub-ppb level and nanometer level.

[0103] (3) Detection and control system:

[0104] The detection control system includes a control unit, an online detection unit, an optional flow detector, and a first return line (optional first auxiliary return line) in a first-order system and a second return line (optional second auxiliary return line) in a second-order system;

[0105] (3.1) an online detection unit, comprising a first sampling tube disposed at the water outlet of the degassing unit 13, a second sampling tube disposed at the water outlet of the degassing ultrafiltration unit, and a detection device connecting the first sampling tube and the second sampling tube, the detection device comprising at least one of a plasma mass spectrometer, an ion chromatograph, a total organic carbon analyzer, a dissolved oxygen analyzer, a microparticle analyzer, a boron analyzer, a silica analyzer, a resistivity meter, and a hydrogen peroxide analyzer;

[0106] (3.2) A control unit, which determines the connection mode between the water outlet of the degassing unit 13 and the water outlet of the degassing ultrafiltration unit according to the detection result of the detection device, including:

[0107] (3.2.1) First-order system reflux method:

[0108] The water outlet of the degassing unit 13 is connected to the pure water storage tank between the first-order system and the second-order system, and / or is connected to the water inlet of the demineralization unit 11 through the first reflux pipeline;

[0109] In normal operation, the first reflux ratio of the first reflux line is above 5%, preferably 9-90%, and more preferably 10-60%. The first reflux ratio is the ratio of the reflux water volume of the first reflux line to the water volume entering the pure water storage tank from the outlet of the degassing unit 13;

[0110] The first reflux pipeline also includes a first auxiliary reflux pipe, which is controllably connected to the inlet of the shallow desalination system 10 upstream of the first-stage system. When the first auxiliary reflux pipe is activated, part or all of the water flow from the water outlet of the degassing unit can be quickly refluxed to the inlet of the shallow desalination system 10;

[0111] (3.2.2) Second-order system reflux method:

[0112] The water outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network, and / or is connected to the pure water storage tank through a second reflux pipeline;

[0113] In normal operation, the second reflux ratio of the second reflux line is above 5%. The specific upper limit is determined according to the test results, downstream water consumption and equipment capacity. Usually, the second reflux ratio is set at 20-80%, preferably 25-80%, and more preferably 25-50%. The second reflux ratio is the ratio of the reflux water volume of the second reflux line to the downstream water consumption.

[0114] The second return line also includes a second auxiliary return pipe, which is controllably connected to the water inlet of the desalination unit of the first-stage system, and / or is controllably connected to the inlet of the shallow desalination system 10 upstream of the first-stage system.

[0115] The first auxiliary return pipe and the second auxiliary return pipe are only conditionally intermittently quickly started, and there may be no water flow in the auxiliary return pipes during the shutdown period.

[0116] (3.3) A plurality of flow detectors are provided in the first hybrid photolysis absorber 12, the second hybrid photolysis absorber 22 or other required locations to provide real-time feedback to the control unit on the amount of water to be treated in the first photolysis zone 121 and the second photolysis zone 221 as well as the flow conditions in the areas that require close attention. The control unit determines the total illumination and irradiation time of the radiation light sources in the first photolysis zone 121 and the second photolysis zone 221 based on the online detection results and the feedback results of the flow detectors, in comparison with the set water quality threshold and the current radiation conditions, thereby determining the specific number of radiation light sources to be turned on and other conditions.

[0117] Based on the second-stage purification equipment and purification process, the first hybrid photolysis absorber 12 and the second hybrid photolysis absorber 22 preferably adopt the same structure, including:

[0118] A. a first shell and a plurality of radiation light sources, wherein the radiation light sources are encapsulated in a transparent hollow closed structure formed by the first shell to form a vacuum radiation cavity;

[0119] The radiation light source includes a VUV / UV low-pressure high-intensity mercury vapor or a low-pressure high-intensity amalgam arc discharge light source, and the radiation light source is connected to the control unit, and the control unit regulates the radiation dose of the radiation light source according to the parameters of the water flow to be purified. Preferably, 1-48 185nm radiation light sources are included, preferably 20-40 radiation light sources, and the illumination and irradiation duration of each radiation light source are independently adjustable, so that the number of radiation light sources to be opened and closed can be selected according to the actual water purification amount and water purification requirements, thereby regulating the overall radiation dose. When multiple radiation light sources are used, the radiation light sources can be grouped and controlled, for example, they are divided into 2-8 groups, each group of about 1-6 radiation light sources, so that the radiation light source groups rotate to work. When it is necessary to more easily and accurately control the radiation dose, increase the number of radiation light source groups and reduce the number of radiation light sources in a single group. Preferably, it is divided into 4-8 groups, each group of about 1-5 radiation light sources.

[0120] Preferably, the first shell is a transparent, heat-insulating, hollow closed structure, made of high-purity transparent quartz with a hydroxyl content of ≤ 5 μg / g and a transmittance greater than 90%;

[0121] B. A second shell is arranged around the first shell, the second shell and its lower supporting orifice plate at the bottom and the connecting cover at the top constitute a photolysis zone, and an inlet pipe is arranged on the lower supporting orifice plate;

[0122] Preferably, the second shell comprises a low-transmittance quartz layer, a shielding reflection layer and a metal-free isolation layer stacked in sequence from the inside to the outside, wherein the shielding reflection layer comprises a vacuum evaporated metal film or a VUV hardened metal film.

[0123] C. A top cover, a third shell and a bottom wall. The top cover, the third shell and the bottom wall are sealed and connected in sequence. An upper orifice plate is arranged around the second shell at the upper part of the inner cavity of the third shell, and a lower orifice plate is arranged around the second shell at the lower part of the inner cavity. A processing area is formed between the upper orifice plate and the third orifice plate;

[0124] Preferably, the third shell is made of thermoplastic resin material polymerized from ethylene or propylene, or fiber-reinforced composite plastic.

[0125] The top cover is sealed and fixed to the connecting cover of the second shell, and a sealed cavity is formed between the top cover and the upper orifice plate, and the second shell has an outflow hole in the sealed cavity;

[0126] A water collecting chamber is formed between the bottom wall and the lower orifice plate, and a through hole and an outflow port for sealing and fixing the inlet pipe are provided on the bottom wall;

[0127] The water to be purified flows into the photolysis zone from the inlet pipe, enters the sealed chamber from bottom to top through the outflow hole, then passes through the upper orifice plate, the treatment zone, and the lower orifice plate from top to bottom to enter the water collection chamber, and enters the degassing unit / degassing ultrafiltration unit from the outflow port.

[0128] In comparison, although the internal and external structures are the same, the processing areas of the first hybrid photodecomposition absorber and the second hybrid photodecomposition absorber have different filling methods:

[0129] In the first hybrid photolysis absorber, the first treatment zone is provided with the positive adsorption layer, the complex reaction layer and the ion polishing layer from top to bottom;

[0130] In the second hybrid photolysis absorber, the catalytic reaction layer and the ion polishing layer are arranged from top to bottom in the second treatment zone.

[0131] In addition, the radiation doses in the photolysis zones of the first hybrid photolysis absorber and the second hybrid photolysis absorber may be the same or different. For example, the radiation dose in the first photolysis zone is 300-800 mJ / cm 2 Adjust the radiation dose in the second photolysis zone to 200-900mJ / cm 2 adjust.

[0132] The purification process using the second-stage purification equipment comprises the following steps:

[0133] S1. Perform a first-stage purification process in a first-stage system to obtain secondary pure water from primary pure water, including:

[0134] S1.1 The pure water pretreated with shallow desalination enters the desalination unit to further remove anions and cations to obtain deep desalted water;

[0135] S1.2 Deep desalted water enters the first mixed photolysis absorber and undergoes photolysis treatment, positive adsorption treatment, complexation reaction treatment and ion polishing treatment in sequence to obtain quasi-secondary pure water;

[0136] S1.3 Quasi-secondary pure water enters the degassing unit, and the dissolved gas and volatile matter are removed to obtain secondary pure water. The outlet water of the degassing unit is sampled for the first time and tested online. The control unit determines, based on the online test result, that the outlet of the degassing unit is connected to the pure water storage tank to enter the second-stage purification treatment, and / or is connected to the inlet of the desalination unit through the first reflux pipeline to perform the first-stage purification treatment again;

[0137] S2, performing a second-stage purification process in a second-stage system to obtain ultrapure water by treating the secondary pure water, comprising:

[0138] S2.1 Secondary pure water is output from the pure water storage tank and enters the membrane absorber. Hydrogen with a purity greater than 99.9% is introduced into the membrane absorber to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l;

[0139] S2.2 The hydrogen-filled water enters the second hybrid photolysis absorber and undergoes photolysis treatment, catalytic reaction treatment and ion polishing treatment in sequence to obtain quasi-ultrapure water;

[0140] S2.3 Quasi-ultrapure water enters the degassing ultrafiltration unit to remove dissolved gases, volatiles and microparticles to obtain ultrapure water. The outlet water of the degassing ultrafiltration unit is sampled for a second time and tested online. The control unit determines, based on the online test results, that the outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network, and / or is connected to the pure water storage tank through a second reflux pipeline for a second-stage purification treatment.

[0141] Specifically, a flow detector is set at least upstream of the inlet pipe of the first hybrid photolysis absorber and the second hybrid photolysis absorber to feed back the amount of water to be treated in the first photolysis zone and the second photolysis zone to the control unit in real time. The control unit determines the total illumination and irradiation time of the radiation light sources in the first photolysis zone and the second photolysis zone according to the online detection results and the feedback results of the flow detector, and compares the set water quality threshold and the current radiation conditions, so as to determine the specific conditions such as the number of radiation light sources turned on. Taking the maximum illumination of all radiation light sources turned on as 100%, the illumination adjustment range of the first photolysis zone and the second photolysis zone is between about 10-100%, preferably between 30-100%. In addition, the radiation light sources can be grouped and controlled, for example, they are divided into 2-8 groups, each group has about 1-6 radiation light sources, so that the radiation light source groups work in rotation. More preferably, they are divided into 4-8 groups, each group has about 1-5 radiation light sources, increasing the number of radiation light source groups and reducing the number of radiation light sources in a single group, so that the radiation dose can be more accurately controlled.

[0142] The radiation dose in the first photolysis zone is 300-800 mJ / cm 2 The radiation dose in the second photolysis zone is 200-900mJ / cm 2 .

[0143] The water quality index of ultrapure water obtained by the above purification process reaches:

[0144] Trace metals <0.05ng / L, TOC <0.5μg / L, DO <0.3μg / L, B <0.5ng / L, H2O2 <1μg / L, concentration of particles larger than 0.05μm <0.1pcs / mL.

[0145] In order to make the purification process of the second-stage purification equipment of the present invention easier to understand, the purification process of the second-stage purification equipment will be described as a whole according to the process flow below:

[0146] 1) Pass the primary pure water obtained from raw water treatment into the continuous electric desalination system;

[0147] 2) The produced water of the continuous electro-deionization system enters the first mixed photolysis absorber through the inlet, flows through the first photolysis zone (from bottom to top), the sealed chamber at the top, the first reaction chamber (from top to bottom), the water collection chamber at the bottom, and leaves the first mixed photolysis absorber from the outlet. In the photolysis zone, the ultraviolet rays radiated by the vacuum radiation chamber are absorbed by water molecules to produce hydroxyl radicals and superoxide radicals, inducing chain reactions to generate a variety of strong oxidizing active substances, which react with the residual soluble pollutants in the water to be purified by addition reaction or hydroxylation reaction, and then undergo hydrogen extraction reaction or redox reaction to degrade the soluble organic matter in the water to form the first treated water. Among them, the core of the reaction is hydroxyl radical (OH·), which can oxidize organic matter into carbon dioxide, water and intermediate products when the 185nm ultraviolet rays irradiate the water flow. After the first treated water enters the sealed cavity, it flows through the first treatment area, first flows through the first positive adsorption area, which can remove low molecular weight acidic organic matter in the water after 185nm UV radiation oxidation, and then flows through the second complex reaction area. The weak ion state of H3BO3 can be removed efficiently in a short life in the positive adsorption area, and can be deeply removed for a long time in the complex reaction area, and its initial leakage concentration even reaches a high level of less than 0.5 ng / l. But at the same time, some high molecular polymers will precipitate in the boron absorbent area, causing the TOC concentration in the water to increase slightly, and the resistivity in the water will decrease to a certain extent. Therefore, when the deboronated water flows through the ion polishing area, it can effectively adsorb the micro-polluted electrolyte released by the NMDG-based adsorbent, control the increased TOC concentration to 1μg / L or even lower, and significantly increase the resistivity of the water. Among them, the ion polishing area and the complex reaction area are filled with different absorption materials and are closely connected. Therefore, after passing through the first hybrid photolysis absorber, low molecular organic matter can be deeply degraded and weakly ionized impurities can be further removed, while high molecular organic matter produced by complexation reaction can be absorbed and resistivity can be increased; inside the first hybrid photolysis absorber, all flow surfaces and water-passing devices in contact with water, including inlet pipes, cavities, partitions, channels, water collectors, etc., are made of high molecular polymer materials or quartz materials, which are different from the alloy steel materials of traditional reactors and exchange towers, so the whole equipment can be demetallized or metal-minimized. In addition, the highly integrated design of the hybrid photolysis absorber can not only save the floor space of at least two devices. Due to the use of light shielding and reflection structural design in the first reaction chamber and the protection measures of filling inert gas in the vacuum radiation chamber to reduce light attenuation, the radiation efficiency is improved; in the transition zone, the transmission distance between devices is shortened, which effectively reduces the accumulation of micro-pollution precipitated from the pipeline material, so even in the ultra-trace detection range, a higher removal effect can be seen.

[0148] 3) The treated water at the outlet passes through a membrane degasser to remove dissolved oxygen (including dissolved gases, volatile substances, etc.) in the water and the resin, and forms secondary pure water after treatment; wherein the outlet of the membrane degasser forms a closed loop with the first reflux pipeline leading to the inlet of the desalination unit, and the pipeline is connected to the pure water storage tank between the first-order system and the second-order system;

[0149] 4) The secondary pure water in the pure water storage tank is ultrapurified by the second-order system. The secondary pure water flows through the membrane absorber, which has a built-in hydrogen-dissolving membrane. The hydrogen-dissolving membrane includes dense tubular hollow fibers. The fiber tube is a hydrophobic material. Water molecules cannot pass through the tube wall, but gas molecules can pass through. Hydrogen is introduced into the tube under pressure, and the hydrogen can be evenly transferred to the water to achieve liquid phase absorption of the gas.

[0150] 5) The produced water of the membrane absorber enters the second hybrid photolysis absorber through the inlet, flows through the second photolysis zone (from bottom to top), the top sealing chamber, the second reaction chamber (from top to bottom), the bottom water collection chamber in turn, and leaves the second hybrid photolysis absorber from the outlet. When the hydrogen-dissolved water flows through the catalytic reaction zone of the second reaction chamber, the decomposition of hydrogen peroxide will produce oxygen on the catalyst surface. Since the water is rich in hydrogen, hydrogen will be adsorbed to the catalyst surface. At the active sites on the catalyst surface, the adsorbed atomic oxygen is preferably hydrogenated to adsorbed hydroxyl, and the adsorbed hydroxyl is further hydrogenated to water, and the product water is desorbed from the catalyst surface. The oxidation reaction of hydrogen under the catalyst framework is also effective for removing dissolved oxygen in water. The trace metals are further removed and the resistivity is increased in the ion polishing area.

[0151] 6) The treated water at the outlet of the second hybrid photolysis absorber passes through a membrane contact degassing device to efficiently remove the trace dissolved gas generated or remaining in the second hybrid photolysis absorber by using membrane degassing technology in a nitrogen and vacuum combined purge mode, so that the residual dissolved oxygen reaches a level of <0.3μg / L; finally, the terminal ultrafiltration device removes all bacteria and particulate impurities to below 0.05μm (the particle number concentration greater than 0.05μm is <0.1pcs / mL).

[0152] Example 1

[0153] A second-order purification device and purification process for ultrapure water, comprising a first-order system and a second-order system connected in sequence, wherein:

[0154] (1) First-order system: The primary pure water is treated to obtain secondary pure water, including a desalination unit, a first hybrid photolysis absorber and a degassing unit connected in sequence:

[0155] (1.1) Desalination unit, including a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower connected in sequence;

[0156] (1.2) The first hybrid photolysis absorber, see Appendix Figure 1 , having a first photolysis zone and a first treatment zone downstream thereof, in the direction of water flow, the first treatment zone sequentially comprises a positive adsorption layer, a complex reaction layer and an ion polishing layer, and the thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is 2:9:4;

[0157] In the first treatment zone, the positively charged adsorption layer includes a positively charged adsorbent, and the positively charged adsorbent is a positively charged adsorption resin with a quaternary ammonium functional group or a mixed resin mixed with a positively charged adsorption resin with a quaternary ammonium functional group;

[0158] The complex reaction layer includes a boron absorber;

[0159] The ion polishing layer includes a mixed ion exchanger having basic groups and acidic groups respectively;

[0160] The radiation dose in the first photolysis zone was 762 mJ / cm 2 , and the illumination and irradiation time of each radiation light source are independently adjustable. The radiation light sources can also be controlled in groups, and the 20 radiation light sources are divided into 5 groups, with 4 radiation light sources in each group.

[0161] (1.3) Degassing unit, including membrane contact degassing device, removes oxygen and carbon dioxide produced by TOC oxidation to form secondary pure water, which is sent to the pure water storage tank. The effluent of the degassing unit is sampled and tested. The TOC mass concentration of the water body is less than 2.5μg / l.

[0162] (2) Second-order system: The secondary pure water is treated to obtain ultrapure water, including a membrane absorber, a second hybrid photolysis absorber and a degassing ultrafiltration unit connected in sequence, specifically:

[0163] (2.1) A membrane absorber, including a hydrogen dissolving membrane and a hydrogen supply pipeline, used to dissolve hydrogen into the secondary pure water to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.08±0.01 mg / l;

[0164] (2.2) a second hybrid photolysis absorber, comprising a second photolysis zone and a second treatment zone downstream thereof, wherein in the direction of water flow, the second treatment zone comprises a catalytic reaction layer and an ion polishing layer in sequence, and the thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:2.5;

[0165] The radiation dose in the second photolysis zone is 396 mJ / cm 2 The TOC mass concentration of the water at the outlet of the second mixed photolysis absorber is below 0.4μg / l; the 40 185nm radiation light sources in the second photolysis zone are divided into 5 groups, with 4 radiation light sources in each group, and the illumination and irradiation time of each radiation light source are independently adjustable.

[0166] (2.3) A degassing ultrafiltration unit, comprising a membrane contact degassing device and an ultrafiltration device connected in sequence, to remove dissolved gases and particulates in the residual water to sub-ppb level and nanometer level.

[0167] The purification process using the second-stage purification equipment comprises the following steps:

[0168] S1. Perform a first-stage purification process in a first-stage system to obtain secondary pure water from primary pure water, including:

[0169] S1.1 The pure water pretreated with shallow desalination enters the desalination unit to further remove anions and cations to obtain deep desalted water;

[0170] S1.2 Deep desalted water enters the first mixed photolysis absorber and undergoes photolysis treatment, positive adsorption treatment, complexation reaction treatment and ion polishing treatment in sequence to obtain quasi-secondary pure water;

[0171] S1.3 Quasi-secondary pure water enters the degassing unit to remove dissolved gases and volatiles to obtain secondary pure water. The outlet water of the degassing unit is sampled and tested;

[0172] S2, performing a second-stage purification process in a second-stage system to obtain ultrapure water by treating the secondary pure water, comprising:

[0173] S2.1 Secondary pure water is output from the pure water storage tank and enters the membrane absorber. Hydrogen with a purity greater than 99.9% is introduced into the membrane absorber to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.08±0.01mg / l;

[0174] S2.2 The hydrogen-filled water enters the second hybrid photolysis absorber and undergoes photolysis treatment, catalytic reaction treatment and ion polishing treatment in sequence to obtain quasi-ultrapure water;

[0175] S2.3 Quasi-ultrapure water enters the degassing ultrafiltration unit to remove dissolved gases, volatiles and microparticles to obtain ultrapure water, which is then sampled and tested.

[0176] Example 2

[0177] The difference between this embodiment and embodiment 1 is that in the first-order system, the thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is 2:9:3, and the effluent water of the degassing unit is sampled and tested, and the TOC mass concentration of the water body is less than 2.7μg / l. In the second-order system, the thickness ratio of the catalytic reaction layer and the ion polishing layer is 1:9.

[0178] Example 3

[0179] The difference between this embodiment and embodiment 1 is that in the first-order system, the thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is 2:10:2, and the effluent water of the degassing unit is sampled and tested, and the TOC mass concentration of the water body is less than 2.8μg / l. In the second-order system, the thickness ratio of the catalytic reaction layer and the ion polishing layer is 1:20.

[0180] Example 4

[0181] The difference between this embodiment and embodiment 2 is that both the first-order system and the second-order system are provided with a reflux pipe to reflux the secondary pure water and ultrapure water. The first reflux ratio of the first reflux line is 30%, and the second reflux ratio of the second reflux line is set at 50% according to the downstream water consumption. The reflux line is set as follows:

[0182] The detection and control system also includes a flow detector, a first reflux line in the first-order system, and a second reflux line in the second-order system. The first reflux ratio of the first reflux line is 30%. The first reflux ratio is the ratio of the reflux water volume of the first reflux line to the water volume entering the pure water storage tank from the water outlet of the degassing unit.

[0183] The second reflux ratio is set to 50%, which is the ratio of the reflux water volume of the second reflux pipeline to the downstream water volume.

[0184] The reflow process steps specifically include:

[0185] In step S1.3, quasi-secondary pure water enters the degassing unit to remove dissolved gases and volatiles to obtain secondary pure water, and the outlet water of the degassing unit is sampled and tested. According to the first reflux ratio set by the first reflux pipeline, the outlet of the degassing unit is connected to the pure water storage tank for the second-stage purification treatment, and is connected to the inlet of the desalination unit through the first reflux pipeline for the first-stage purification treatment again; after stabilization, the TOC mass concentration of the outlet water of the degassing unit is less than 2μg / l.

[0186] In step S2.3, quasi-ultrapure water enters the degassing ultrafiltration unit to remove dissolved gases, volatiles and microparticles to obtain ultrapure water, and the outlet water of the degassing ultrafiltration unit is sampled and tested. According to the second reflux ratio set by the second reflux line, the outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network and connected to the pure water storage tank through the second reflux pipeline for secondary purification treatment again.

[0187] Example 5

[0188] The difference between Example 5 and Example 4 is that the first auxiliary reflux pipe and the second auxiliary reflux pipe are opened within 24 hours after the equipment is started, the first auxiliary reflux pipe transports 60% of the reflux water of the first reflux line (the first reflux ratio is 30%) to the inlet of the shallow desalination system upstream of the first-order system, the second auxiliary reflux pipe transports 30% of the reflux water of the second reflux line (the second reflux ratio is set to 40%) to the water inlet of the desalination unit of the first-order system, and transports 30% of the reflux water of the second reflux line to the inlet of the shallow desalination system upstream of the first-order system, thereby quickly improving the quality of the output ultrapure water within 24 hours.

[0189] Example 6

[0190] The difference between this embodiment and embodiment 4 is that both the first-order system and the second-order system are provided with a reflux pipe, and the reflux ratio is regulated based on the online detection and reflux treatment of the secondary pure water and ultrapure water.

[0191] The purification process using the second-stage purification equipment further includes the following steps:

[0192] (1) The secondary pure water flowing out of the degassing unit is sampled for the first time and tested online. The control unit determines the first reflux ratio of the degassing unit outlet to be dynamically adjusted between 10% and 60% according to the online test result; accordingly,

[0193] (2) The ultrapure water flowing out of the degassing ultrafiltration unit is sampled for a second time and tested online. The control unit determines the second reflux ratio of the degassing ultrafiltration unit outlet to be dynamically adjusted to about 50% based on the online test result.

[0194] A flow detector is set upstream of the inlet pipe of the first hybrid photolysis absorber and the second hybrid photolysis absorber to feed back the amount of water to be treated in the first photolysis zone and the second photolysis zone to the control unit in real time. The control unit determines the total illumination and irradiation time of the radiation light sources in the first photolysis zone and the second photolysis zone according to the online detection results and the feedback results of the flow detector, and compares the set water quality threshold and the current radiation conditions, thereby determining the specific number of radiation light sources to be turned on and other conditions. The first photolysis zone and the second photolysis zone are basically equipped with 40 185nm radiation light sources, which are divided into 8 groups, each with 5 radiation light sources, and the illumination and irradiation time of each radiation light source are independently adjustable. Based on the signal of the control unit, one group of light sources is added or reduced on the basis of the 8 groups of light sources. After stabilization, the TOC mass concentration of the effluent of the first-order system degassing unit is less than 2μg / l.

[0195] Comparative Example 1

[0196] This comparative example is based on the setting of invention CN115636557B, and is different from Example 2 in that only a complex reaction layer and a positively charged adsorption layer are sequentially arranged in the first-order system, and the thickness ratio thereof is about 3:2;

[0197] In the second-order system, the positive adsorption layer: the complex reaction layer: the ion polishing layer are arranged in sequence, and the thickness ratio thereof is about 1:2:3.

[0198] Comparative Example 2

[0199] This comparative example is derived from the invention CN115626745B. Compared with Example 2, the ultrapure water is treated only once, wherein the thickness ratio of the positive adsorption layer, the complex reaction layer, and the ion polishing layer sequentially arranged in the first-stage treatment is 1:2:3.

[0200] When the water is continuously passed for two days, the output water body detection data of each embodiment and comparative example are shown in Table 1:

[0201] Table 1 Output water body detection data of the embodiment and the comparative example

[0202]

[0203] In the embodiment of the present invention, the pretreated primary pure water enters the first photolysis zone after passing through the desalination unit (continuous electric desalination system EDI), and ultraviolet rays are absorbed by water molecules to generate hydroxyl radicals and superoxide radicals, which induce chain reactions to generate a variety of strong oxidizing active substances, which react with the residual soluble pollutants in the water to be purified by addition reactions or hydroxylation reactions, and then undergo hydrogen abstraction reactions or redox reactions to degrade the soluble organic matter in the water and convert them into carbon dioxide, water and intermediate products.

[0204] The water flows through the positive adsorption zone to remove low molecular weight acidic organic matter in the water after radiation oxidation, and then flows through the complex reaction zone, where H3BO3 is deeply removed. However, at the same time, some high molecular weight polymers will precipitate in the complex reaction zone, causing the TOC concentration in the water to increase slightly, and the resistivity in the water will decrease to a certain extent. Therefore, when the boron-removed water flows through the ion polishing zone, it can effectively adsorb the micro-polluted electrolytes released by the NMDG-based adsorbent, control the increased TOC concentration at a low level, and significantly increase the resistivity of the water. Among them, the ion polishing zone and the complex reaction zone are filled with different absorption materials and are closely connected. Therefore, after passing through the first hybrid photolysis absorber, low molecular organic matter can be deeply degraded and weakly ionized impurities can be removed, while high molecular organic matter produced by complexation reaction can be absorbed and resistivity can be increased; inside the first hybrid photolysis absorber, all flow surfaces and water-passing devices including inlet pipes, cavities, baffles, channels, water collectors, etc. that are in contact with water are different from the alloy steel materials of traditional reactors and exchange towers, and are made of high molecular polymer materials or quartz materials, so the whole equipment can be demetallized or metal-minimized. Subsequently, the treated water of the first hybrid photolysis absorber is degassed by the degassing unit to remove dissolved oxygen (including dissolved gases, volatile substances, etc.) in the water and resin, and secondary pure water is formed after treatment, and preferably forms a closed circulation loop with the water leading to the inlet of the desalination unit, and the remaining secondary pure water is sealed in the pure water storage tank.

[0205] It can be seen that the first-order system integrates the basic guarantee link of desalination, the photolysis and absorption enhanced treatment link and the degassing link, which can obtain high-quality secondary pure water, and combined with detection methods and reflux design, it can control the quality and flow of secondary pure water more efficiently.

[0206] In the second-order system, the secondary pure water first flows through the membrane absorber, which has a built-in gas transfer membrane. The gas transfer membrane contains dense tubular hollow fibers. The fiber tubes are hydrophobic materials. Water molecules cannot pass through the tube wall, but gas molecules can pass through. Hydrogen is purged in the tube, and the hydrogen can be evenly transferred to the water to achieve liquid phase absorption of the gas. The gas transfer membrane can effectively increase the hydrogen concentration in the water. When the hydrogen-dissolved water flows through the catalytic reaction zone of the second hybrid photolysis absorber, since the metal catalyst preferably uses a supported metal catalyst, the catalyst matrix itself can be a positively charged adsorbent, which can effectively adsorb low-molecular acidic organic matter produced by ultraviolet oxidation, and can decompose H2O2 at the same time. Under the action of H2, the decomposition byproduct O2 is reduced to H2O. An appropriate amount of H2 can further catalytically reduce DO in the water to H2O on the surface of the supported metal catalyst matrix, which is particularly beneficial to quickly reduce the DO value of the output ultrapure water and control it to less than 0.3ppb, and then further remove trace metals and increase resistivity through the ion polishing zone. Therefore, the trace metal ions, weakly ionized impurities, dissolved oxygen and low molecular organic matter can be deeply removed, absorbed and degraded by the second hybrid photolysis absorber, and removed to the extremely low index limit values ​​of ppq, ppt and ppb levels respectively, and the free radical complex oxidants generated by the catalytic reduction photolysis process can also be controlled at the sub-μg / L level. The treated water of the second hybrid photolysis absorber is then degassed to remove the trace dissolved gas generated or remaining in the second hybrid photolysis absorber by membrane degassing technology in a nitrogen and vacuum combination purge mode, so that the residual dissolved oxygen is further reduced, and finally all bacteria and microparticle impurities are further removed by terminal ultrafiltration.

[0207] It can be seen that the second-order system integrates the hydrogen dissolution and deoxygenation, photolysis and absorption enhanced treatment and degassing ultrafiltration steps, which can obtain high-quality ultrapure water. In combination with downstream water supply needs, detection methods and reflux design, it can control the quality and flow of ultrapure water in a more efficient and high-quality manner to meet the water needs of downstream semiconductor processes.

[0208] This invention is an important research achievement of the key special project of the National Key R&D Program "Intergovernmental International Innovation Cooperation" (Project No.: 2023YFE0114100), and has broad application prospects and huge economic value in the field of ultrapure water preparation for integrated circuit cleaning.

[0209] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the present invention is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention.

Claims

1. A second-stage purification device for ultrapure water, characterized in that: Includes first-order and second-order systems connected in sequence; The first-stage system processes primary pure water to obtain secondary pure water, including a desalination unit, a first hybrid photolysis absorber, and a degassing unit; The second-stage system processes the secondary pure water to obtain ultrapure water, including a membrane absorber, a second hybrid photolysis absorber and a degassing ultrafiltration unit; The first hybrid photolysis absorber comprises a first photolysis zone and a first treatment zone downstream thereof. In the direction of water flow, the first treatment zone comprises a positive adsorption layer, a complex reaction layer and an ion polishing layer in sequence. The thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is (1-4): (8-10): (1-4); the radiation dose of the first photolysis zone is 300-800 mJ / cm 2 ; The membrane absorber includes a hydrogen dissolving membrane and a hydrogen supply pipeline, which is used to charge the secondary pure water with dissolved hydrogen and provide hydrogen-charged water with a dissolved hydrogen concentration of 0.05-0.1 mg / l for the downstream second hybrid photolysis absorber; The second hybrid photolysis absorber has a second photolysis zone and a second treatment zone downstream thereof. In the direction of water flow, the second treatment zone includes a catalytic reaction layer and an ion polishing layer in sequence. The thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:(2.5-20); the radiation dose of the second photolysis zone is 200-900mJ / cm 2 ; In the first treatment zone, the positive adsorption layer includes a positively charged adsorbent, which is a positively charged adsorption resin with a quaternary ammonium functional group or a mixed resin mixed with a positively charged adsorption resin with a quaternary ammonium functional group; the complex reaction layer includes a boron absorbent; and the ion polishing layer includes a mixed ion exchanger with a basic group and an acidic group respectively; In the second treatment zone, the catalytic reaction layer includes a supported metal nanoparticle catalyst; the ion polishing layer includes a mixed ion exchanger having a basic group and an acidic group respectively; The ultrapure water quality provided by the second-stage purification equipment to the ultrapure water supply network reaches: Trace metals <0.05ng / L, TOC <0.5μg / L, DO <0.3μg / L, B <0.5ng / L, H2O2 <1μg / L, concentration of particles larger than 0.05μm <0.1pcs / mL.

2. The second-stage purification device according to claim 1, characterized in that: The first hybrid photodecomposition absorber and the second hybrid photodecomposition absorber have the same structure, including: A first shell and at least one radiation light source, wherein the radiation light source is encapsulated in a transparent hollow closed structure formed by the first shell to form a vacuum radiation chamber; A second shell is arranged around the first shell, the second shell and the lower supporting orifice plate at the bottom and the connecting cover at the top form a photolysis zone, and the lower supporting orifice plate is provided with an inlet pipe; The top cover, the third shell and the bottom wall are sealed and connected in sequence, an upper orifice plate is arranged around the second shell at the upper part of the inner cavity of the third shell, and a lower orifice plate is arranged around the second shell at the lower part of the inner cavity, and a processing area is formed between the upper orifice plate and the lower orifice plate; The top cover is sealed and fixed to the connecting cover of the second shell, and a sealed cavity is formed between the top cover and the upper orifice plate, and the second shell has an outflow hole in the sealed cavity; A water collecting chamber is formed between the bottom wall and the lower orifice plate, and a through hole and an outflow port for sealing and fixing the inlet pipe are provided on the bottom wall; The water to be purified enters the photolysis zone from the inlet pipe, enters the sealed chamber from bottom to top through the outflow hole, then passes through the upper orifice plate, the treatment zone, and the lower orifice plate from top to bottom to enter the water collecting chamber, and enters the degassing unit from the outflow port; The processing areas of the first hybrid photodecomposer and the second hybrid photodecomposer have different filling modes: In the first hybrid photolysis absorber, the first treatment zone is provided with the positive adsorption layer, the complex reaction layer and the ion polishing layer from top to bottom; In the second hybrid photolysis absorber, the catalytic reaction layer and the ion polishing layer are arranged from top to bottom in the second treatment zone.

3. The second-stage purification device according to claim 1 or 2, characterized in that: In the first-order system, the desalination unit includes at least one of a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower; the degassing unit includes a membrane contact degassing device; In the second-stage system, the degassing ultrafiltration unit includes a membrane contact degassing device and an ultrafiltration device.

4. The second-stage purification device according to claim 3, characterized in that: The second-stage purification equipment also includes an online detection unit and a control unit. The online detection unit includes a first sampling tube arranged at the water outlet of the degassing unit, a second sampling tube arranged at the water outlet of the degassing ultrafiltration unit, and a detection device connecting the first sampling tube and the second sampling tube. The control unit determines the connection mode of the water outlet of the degassing unit and the water outlet of the degassing ultrafiltration unit according to the detection result of the detection device, including: The water outlet of the degassing unit is controlled to be connected to the pure water storage tank between the first-order system and the second-order system, and / or connected to the water inlet of the desalination unit through the first reflux pipeline; The water outlet of the degassing ultrafiltration unit is controllably connected to the ultrapure water supply network, and / or is connected to the pure water storage tank through a second reflux line.

5. The second-stage purification device according to claim 4, characterized in that: The first reflux line includes a first auxiliary reflux pipe, which is controllably connected to an inlet of a shallow desalination system upstream of the first-stage system; The second return pipeline includes a second auxiliary return pipe, which is controllably connected to the water inlet of the desalination unit of the first-stage system, and / or is controllably connected to the inlet of the shallow desalination system upstream of the first-stage system.

6. The second-stage purification device according to claim 4 or 5, characterized in that: The detection device includes at least one of a plasma mass spectrometer, an ion chromatograph, a total organic carbon analyzer, a dissolved oxygen analyzer, a microparticle analyzer, a boron analyzer, a silica analyzer, a resistivity meter and a hydrogen peroxide analyzer.

7. A purification process using the second-stage purification device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Perform a first-stage purification process in a first-stage system to obtain secondary pure water from primary pure water, including: S1.1 The pure water after shallow desalination pretreatment enters the desalination unit to further remove anions and cations to obtain deep desalted water; S1.2 Deep desalted water enters the first mixed photolysis absorber and undergoes photolysis treatment, positive adsorption treatment, complexation reaction treatment and ion polishing treatment in sequence to obtain quasi-secondary pure water; S1.3 Quasi-secondary pure water enters the degassing unit to remove dissolved gases and volatiles, obtains secondary pure water, and enters the pure water storage tank; S2, performing a second-stage purification process in a second-stage system to obtain ultrapure water by treating the secondary pure water, comprising: S2.1 Secondary pure water is output from the pure water storage tank and enters the membrane absorber. Hydrogen with a purity greater than 99.9% is introduced into the membrane absorber to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l; S2.2 The hydrogen-filled water enters the second hybrid photolysis absorber and undergoes photolysis treatment, catalytic reaction treatment and ion polishing treatment in sequence to obtain quasi-ultrapure water; S2.3 Quasi-ultrapure water enters the degassing ultrafiltration unit to remove dissolved gases, volatiles and microparticles to obtain ultrapure water.

8. The purification process according to claim 7, characterized in that: In step S1.3, the outlet water of the degassing unit is sampled for the first time and tested online, and the control unit determines, based on the online test result, that the outlet of the degassing unit is connected to the pure water storage tank to enter the second-order purification treatment, that the inlet of the desalination unit is connected to the water inlet of the desalination unit to perform the first-order purification treatment again, and / or that the inlet of the shallow desalination system upstream of the first-order system is connected to perform the shallow desalination pretreatment again; In step S2.3, the outlet water of the degassing ultrafiltration unit is sampled for a second time and tested online, and the control unit determines, based on the online test results, that the outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network, connected to the pure water storage tank for a second-order purification treatment, connected to the water inlet of the desalination unit for a first-order purification treatment, and / or connected to the inlet of the shallow desalination system upstream of the first-order system for a shallow desalination pretreatment.

9. The purification process according to claim 8, characterized in that: The control unit regulates the radiation dose of the first photolysis zone and the radiation light source of the first photolysis zone respectively according to the parameters of the water flow to be purified; Determine the connection mode of the water outlet of the degassing unit according to the online detection result of the first sampling; According to the online detection result of the second sampling, the connection mode of the water outlet of the degassing ultrafiltration unit is determined; The quality of ultrapure water provided to the ultrapure water supply network reaches: Trace metals <0.05ng / L, TOC <0.5μg / L, DO <0.3μg / L, B <0.5ng / L, H2O2 <1μg / L, concentration of particles larger than 0.05μm <0.1pcs / mL.

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