Second-order purification equipment and purification process for ultrapure water

Abstract

The invention relates to ultrapure water second-order purification equipment and a purification process. The equipment comprises a first-order system and a second-order system which are connected in sequence, the first-order system is used for treating primary pure water to obtain secondary pure water and comprises a desalting unit, a first mixed photolysis absorber and a degassing unit; the second-order system is used for treating secondary pure water to obtain ultrapure water and comprises a membrane absorber, a second mixed photolysis absorber and a degassing ultrafiltration unit; the first mixed photolysis absorber is provided with a first photolysis area and a first treatment area at the downstream of the first photolysis area, and the radiation dose of the first photolysis area is 300-800 mJ / cm < 2 >; the membrane absorber comprises a hydrogen dissolving membrane and a hydrogen supply pipeline, and provides hydrogen filling water for the downstream second mixed photolysis absorber; the second mixed photolysis absorber is provided with a second photolysis area and a second treatment area at the downstream of the second photolysis area, and the radiation dose of the second photolysis area is 200-900 mJ / cm < 2 >. According to the invention, comprehensive control of various indexes of the ultrapure water is effectively realized, and guarantee is provided for a nano semiconductor manufacturing process and processing quality.

Description

Technical Field

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

[0002] Ultrapure water is a crucial element in ensuring the quality of nano-semiconductor manufacturing processes. It is primarily used in semiconductor production processes, such as product cleaning and chemical dilution. In recent years, with the shrinking of semiconductor device process nodes, the production process water has placed extremely high demands on trace metals, total organic carbon (TOC), total silicon, microparticles, and dissolved oxygen (DO). Developing advanced ultrapure water preparation processes to meet the water quality requirements of cutting-edge semiconductor processes and achieve the combined removal of multiple pollutants to achieve comprehensive control of trace metals, TOC, boron (B), DO, H2O2, and other indicators has become an urgent need.

[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 passes through a first mixed photolysis absorber to degrade total organic carbon and remove weakly ionized impurities. Subsequently, 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 passes through a catalytic mixed photolysis absorber to remove trace metal ions, weakly ionized impurities and low-molecular organic matter to the ppq level, ppt level and ppb level, respectively, while the free radical complex oxidant is controlled at the sub-ppb level.

[0004] Invention patent CN115626745B discloses a device and method for purifying cleaning water for advanced chip manufacturing. In the purification device, at least one first shell is a transparent, heat-insulating, hollow, enclosed structure; at least one radiation light source is arranged in the hollow, enclosed 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 with the photolysis zone to photocatalytically oxidize the water to be purified to form first treated water; the first treated water from the sealed chamber is sequentially removed from carboxylic acid small molecular organic matter and carbonic acid in the positive adsorption zone, quenches free radical complex oxidants in the catalytic reaction zone, and reduces 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] While the aforementioned invention provides a novel, full-process solution for ultrapure water production in the field of high-end nano-integrated circuit manufacturing, in certain more stringent applications, the O₂ byproduct produced by the hybrid photolysis absorber or purification unit increases micro-contamination of dissolved gases in the water, increasing the burden and risk of DO control in the critical ultrapure water process below 7 nm. Furthermore, the release of O₂ from the dissociation of nanoparticles easily forms an oxide layer or film on their surface, reducing decomposition efficiency. In the deep desalination stage, the boron adsorbent in the hybrid photolysis absorber is also susceptible to inhibition and competition from the organic acids produced by photolysis, which in turn affects boric acid adsorption efficiency.

[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, while avoiding secondary pollution of water quality by 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 solved urgently by technical personnel in this field. Summary of the Invention

[0007] In response to the defects 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 the ultrapure water purification equipment and process flow, it effectively achieves comprehensive control of indicators such as trace metals, TOC, boron (B), DO, H2O2, etc., providing guarantees for the manufacturing process and processing quality of nano-semiconductors.

[0008] In a first aspect, the present invention provides a second-stage purification device for ultrapure water, comprising a first-stage system and a second-stage system 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): (1-12): (1-6); 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 provides hydrogen-filled water 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: (1-50); the radiation dose of the second photolysis zone is 200-900mJ / cm 2 .

[0009] Preferably, 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 containing 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; The thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is (1-4): (8-10): (1-4).

[0010] 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.

[0011] The thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:(1.2-50), more preferably 1:(2.5-20).

[0012] Compared with previous water purification devices, especially hybrid photolysis absorbers, the present invention has researched and explored a more efficient and stable combination of a first hybrid photolysis absorber and a second hybrid photolysis absorber, as well as their internal filling method and filling thickness design.

[0013] 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.

[0014] The positively charged adsorbent is a strong adsorbent having a positive charge and containing or mixed with a quaternary ammonium functional group. One method for preparing this adsorbent is to use a chloromethylated polystyrene cross-linked resin skeleton with main raw materials such as dimethylbenzene and trimethylamine through suspension polymerization, chloromethylation, and amination. Preferably, a gel-type divinylbenzene cross-linked adsorbent with trimethylbenzylammonium groups or a mixed resin containing this adsorbent is selected. This has a stronger adsorption function for anionic electrolytes in water, especially small molecular organic matter. Furthermore, it is more preferred to select a high-purity model of this type of adsorbent to ensure and meet the strict requirement of TOC mass concentration ≤1μg / l, preferably ≤0.5μg / l.

[0015] The boron absorbent is a monodisperse porous absorbent, including methylamine-based granular beads or chelating resin. The boron absorbent can be formed by grafting aliphatic polyols or aromatic polyhydroxyphenols onto a polymer backbone. Preferably, to overcome the limitations of porous hydrophobic polymer backbones, which are difficult to infiltrate and affect mass transfer, and the defects of the crosslinker divinylbenzene in the backbone containing multiple isomers, which significantly affect the performance of the polymer structure, poly(glycidyl 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 onto the macroporous particle skeleton of the copolymer dissolved in dimethyl sulfoxide solution to prepare the high-efficiency 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 carbon chain polyol is used as the functional monomer. A one-step adsorption method is used, followed by stirring, eluting, and drying to prepare a monodisperse porous resin boron absorbent containing ortho- and meta-dihydroxy functional groups.

[0016] The mixed ion exchanger of the ion polishing layer is preferably an ion exchanger with two ions pre-mixed in a certain proportion, each with alkaline and acidic groups. 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 non-regenerable.

[0017] The metal catalyst is preferably a multiphase metal catalyst that forms a polymer complex by directly bonding a transition metal to a copolymer skeleton such as styrene and acrylic acid; 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; furthermore, 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 the heterophase platinum group metal by means of a coordinated covalent bond. (palladium, platinum, ruthenium, rhodium, osmium, iridium) ion precursors, and reduction transformation to form a heterogeneous gel-type or macroporous resin matrix catalyst, typically, such as: gel-type polystyrene-loaded nano-palladium metal catalyst; also optional, using amine-functionalized PS microspheres as polymer carriers, applying the heterogeneous coagulation method based on thermodynamic principles, 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 to obtain a nano alloy composite particle catalyst.

[0018] 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 producing oxygen. The thermochemical equation is expressed as: H2O2 (l)=H2O(l)+1 / 2O2 (g) ΔH=-105.8 kJ / mol Preferably, the first hybrid photodecomposer and the second hybrid photodecomposer have the same structure, including: A first housing and at least one radiation light source, wherein the radiation light source is encapsulated in a transparent hollow closed structure formed by the first housing to form a vacuum radiation cavity; The second shell is arranged around the first shell, and the second shell, together with the lower supporting orifice plate at the bottom and the connecting cover at the top, constitute 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. A processing area is formed between the upper orifice plate and the third 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. 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 flows into the photolysis zone from the inlet pipe, enters the sealed chamber from bottom to top through the outflow hole, and 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 from the outflow outlet; In the first hybrid photodecomposition 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 photodecomposition absorber, the catalytic reaction layer and the ion polishing layer are arranged in the second processing zone from top to bottom.

[0019] The first and second hybrid photodecomposers are preferably cylindrical in shape, surrounded by multiple coaxial cylindrical shells of varying radii. The first cylindrical shell forms a transparent, hollow, enclosed structure. Made of high-purity transparent quartz with a hydroxyl content of ≤5μg / g and a transmittance greater than 90%, it prevents the treated water from removing heat from the light source, preventing the temperature within the vacuum radiation chamber from dropping too low and affecting luminous efficiency. Its thermal insulation also stabilizes the UV light output, ensuring that variations in water temperature between 5°C and 32°C have little effect on the output intensity of the discharge light source. The second cylindrical shell comprises 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. This prevents reflection losses at multiple interfaces caused by Fresnel reflection, effectively improving reflectivity. The third cylindrical shell or its inner surface is constructed from a thermoplastic resin material derived from ethylene or propylene polymerization, or a fiber-reinforced composite plastic.

[0020] 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; In the second-stage system, a membrane absorber is used to dissolve hydrogen in the secondary pure water, producing hydrogen-charged water with a dissolved hydrogen concentration of 0.05-0.1 mg / l. The degassing and ultrafiltration unit includes a membrane contact degasser and an ultrafiltration unit. Furthermore, booster pumps, metering pumps, sampling points, and other components may be installed between the units or devices of the first-stage and second-stage systems as needed. Preferably, a booster pump is also installed between the membrane contact degasser and the ultrafiltration unit.

[0021] The present invention incorporates a hydrogen-dissolving membrane within the membrane absorber of a second-order system, positioned upstream of a second hybrid photolysis absorber. By pressure-injecting hydrogen, high-purity hydrogen is evenly transferred into the water, achieving liquid-phase absorption of the gas. Preferably, the flow path is connected using a mixed flow ratio adjustment method, where it mixes with the effluent from the pure water storage tank. The mixed water to be purified enters the second hybrid photolysis absorber. When the hydrogen-charged water flows through the catalytic reaction layer of the second hybrid photolysis absorber, hydrogen peroxide decomposes on the catalyst surface to produce oxygen (refer to the aforementioned thermochemical equation). Because the water is rich in hydrogen, hydrogen is adsorbed onto the catalyst surface. At the active sites on the catalyst surface, the adsorbed atomic oxygen is preferably hydrogenated to adsorbed hydroxyl groups, and the adsorbed hydroxyl groups are further hydrogenated to water. The product water desorbs from the catalyst surface. The hydrogen oxidation reaction within this catalyst architecture is also effective for removing dissolved oxygen from water. This approach also effectively addresses the issues of surface oxidation, performance degradation, and shortened lifespan of the catalyst after prolonged use, avoiding the limited recovery steps of operation, extraction, soaking, and cleaning, and the associated contamination risks. 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%.

[0022] 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 provided at the water outlet of the degassing unit, a second sampling tube provided 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 communication mode between the water outlet of the degassing unit and the water outlet of the degassing ultrafiltration unit according to the detection results 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 demineralization unit through the first reflux pipeline; The water outlet of the degassing ultrafiltration unit is controlled to be connected to the ultrapure water supply network, and / or is connected to the pure water storage tank through a second reflux line.

[0023] 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 The second return line 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.

[0024] Based on the setting of the first return pipeline and the second return pipeline, the present invention further refines the return pipeline, and adds at least one first auxiliary return pipe and at least one second auxiliary return pipe, which can be opened or closed according to the instructions of the control unit, especially according to the return instruction of the control unit to adjust the ratio of each return flow diversion.

[0025] Specifically, when the conventional system is operating, 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.

[0026] Similarly, there may be no return water in the second auxiliary return 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 phase, the second-order system, on the basis of ensuring stable water output, uses at least one second auxiliary return pipe to connect the water inlet of the desalination unit to perform a first-order purification treatment again, and / or connects to the inlet of the shallow desalination system upstream of the first-order system to perform a shallow desalination pretreatment again. This corresponds to the use scenarios of trial operation, before the water quality meets the standard, closing the outlet valve for self-circulation within the station, etc.; in the production state, only when the secondary pure water is unqualified due to the excessive use of the primary pure water and does not affect the process water consumption, it can be partially switched to the second auxiliary return pipe, and only supply water to the first-order system and its upstream.

[0027] Furthermore, to obtain qualified primary pure water, the water to be purified must have undergone at least one desalination step in a shallow desalination system (or pre-desalination system), preferably two desalination steps, including a double bed and reverse osmosis process. Therefore, the first and second auxiliary return lines do not need to extend to the raw water tank; their furthest return points can be at the shallow desalination system inlet. Together with the upstream pretreated water, they enter the shallow desalination system's demineralized water tank (DI water tank) for treatment, resulting in high-quality primary pure water.

[0028] 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 testing methods and indicators, and the above detection devices are not exhaustive. These devices may be selected or added or removed based on actual water use requirements.

[0029] 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: In the default state where the secondary return water returns to the pure water storage tank, if the water quality test value of the secondary treatment is poor, the secondary return water can be partially / completely returned to the water inlet of the desalination unit of the primary treatment or the inlet of the shallow desalination system upstream of the primary system; In the default state where the first-stage return water returns to the water inlet of the desalination unit, when the water quality test value of the first-stage treatment is poor, the first-stage return water can be partially / completely returned to the inlet of the shallow desalination system upstream of the first-stage system, or when the water quality test value of the first-stage treatment is poor due to the primary pure water exceeding the standard, the second-stage return water can be partially returned to the first-stage system and its upstream to replenish the first-stage system without affecting the process water consumption.

[0030] 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 (significant water quality deterioration, water quality decline caused by upstream pollution or trial operation stage, etc.), which are not normal circulation modes. Therefore, it basically does not constitute a switching burden on the system and control unit.

[0031] 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 water for cutting-edge semiconductor process technology; 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, reflux and other methods of the first-order system and the second-order system, it is possible to accurately grasp the purification status of the water flow at each stage, match the corresponding radiation dose 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.

[0032] 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.

[0033] The first and second photolysis zones preferably include several 185nm radiation sources, for example, 1-48 radiation sources, preferably 20-40 radiation sources. The illumination intensity and duration of each radiation source are independently adjustable, allowing the number of radiation sources to be switched on and off based on the actual water purification volume and requirements, thereby regulating the overall radiation dose. Radiation sources can provide high-intensity radiation, sufficient for water treatment. However, since radiation sources themselves are expensive to manufacture and operate, and typically require replacement approximately once a year, the present invention regulates the illumination intensity and duration of the radiation sources based on actual water consumption and water quality requirements, thereby significantly reducing operating and replacement costs. Optionally, when using multiple radiation sources, the radiation sources can be grouped and controlled, for example, in 2-8 groups, each containing approximately 1-6 radiation sources, so that the radiation source groups can rotate in operation.

[0034] A second aspect of the present invention further provides a purification process using the second-stage purification device, comprising the following steps: 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 primary 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 hybrid photolysis absorber and undergoes photolysis, positive adsorption, complexation and ion polishing in sequence to obtain quasi-secondary pure water; S1.3 Quasi-secondary pure water enters the degassing unit to remove dissolved gases and volatiles to obtain secondary pure water, which is then input into the pure water storage tank; S2. Performing a second-stage purification process in a second-stage system to obtain ultrapure water from 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-charged water with a dissolved hydrogen concentration of 0.05-0.1 mg / l. S2.2 The hydrogen-charged water enters the second hybrid photolysis absorber and undergoes photolysis, catalytic reaction, and ion polishing 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.

[0035] The purification process of the present invention uses a pretreatment system to perform shallow desalination on raw water to produce primary pure water. The water quality characteristics of primary pure water meet the requirements of TOC <50μg / L, conductivity <2μS / cm, boron (B) <10μg / L, and DO <10 mg / L. The primary pure water enters the first-stage system, passes through the desalination unit, and deeply removes anions and cations, as well as a small amount of TOC. The water then passes through the three-layer treatment agent (a positive adsorption layer, a complex reaction layer, and an ion polishing layer, stacked from top to bottom) in the first hybrid photodecomposition absorber to degrade low-molecular-weight organic matter (LMWOM) and further remove weakly ionized impurities, without reducing resistivity due to contamination. Specifically, the positively charged adsorbent in the positive adsorption layer efficiently adsorbs low-molecular-weight acidic organic compounds (LMW CAs) produced by 185nm UV oxidation of LMWOM. This is then complexed with the boron absorbent in the complexation reaction layer to achieve deep boron removal. The ion exchanger in the ion polishing layer removes micro-contaminant electrolytes released by the NMDG-based absorbent, inhibiting resistivity decline and controlling increased TOC concentration to 1μg / L or even lower, comprehensively improving produced water quality. The degassing unit then removes dissolved oxygen (including dissolved gases and volatile substances) in the water and resin, producing secondary pure water.

[0036] The secondary pure water is then subjected to catalytic and polishing treatments by a second-stage system. The secondary pure water first passes through a membrane absorber (MGA), where high-purity H2 is dissolved using a hydrogen-dissolving membrane. The water then passes through a second hybrid photolysis absorber filled with two layers of treatment agents (a catalytic reaction layer and an ion polishing layer, stacked from top to bottom). These layers can further deeply remove, absorb, and degrade trace metal ions, dissolved oxygen, weakly ionized impurities, and low-molecular organic matter, treating them to extremely low limit values ​​of ppq, ppt, and ppb, respectively. At the same time, the free radical complex oxidant (H2O2) produced by the catalytic photolysis process can be controlled to a sub-ppb level (as low as 1ug / L or less). Specifically, because the metal catalyst in the catalytic reaction layer is a supported metal catalyst, the catalyst matrix itself can be a positively charged adsorbent, effectively adsorbing low-molecular-weight acidic organic compounds (LMW CAs) produced by 185nm UV oxidation of LMWOM. It can also decompose H2O2 to less than 1μg / L, preferably less than 0.8μg / L. The decomposition byproduct O2 can also be reduced to H2O under the action of H2. An appropriate amount of H2 can also catalyze the reduction of O2 in water to H2O on the surface of the supported metal catalyst matrix. The ion exchanger in the ion polishing layer further removes trace metals and increases resistivity. Finally, membrane degassing and ultrafiltration in the degassing ultrafiltration unit achieve polishing and removal of dissolved gases and microparticles.

[0037] 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 results, whether the outlet of the degassing unit is connected to the pure water storage tank to enter the second-stage purification treatment, whether the outlet of the degassing unit is connected to the water inlet of the desalination unit to undergo the first-stage purification treatment again, and / or whether the outlet of the desalination unit is connected to the inlet of the shallow desalination system upstream of the first-stage system to undergo the shallow desalination pretreatment again; In step S2.3, the outlet water of the degassing ultrafiltration unit is sampled for the 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, connected to the pure water storage tank for a second-stage purification treatment, connected to the water inlet of the desalination unit for a first-stage purification treatment, and / or connected to the inlet of the shallow desalination system upstream of the first-stage system for a shallow desalination pretreatment.

[0038] During normal system operation, the first reflux ratio of the first reflux line is above 5%, preferably between 9% and 90%. This ratio is the ratio of the return water volume of the first reflux line to the water volume entering the pure water storage tank from the degassing unit outlet per unit time. If water quality deteriorates significantly, the first auxiliary reflux line can be opened to quickly redirect some or all of the return water upstream through the first auxiliary reflux line.

[0039] Unlike the first reflux ratio, due to the need to closely monitor 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 to the downstream water consumption per unit time. The second reflux ratio is usually set at 20-80%, preferably 25-50%. Similarly, during normal system operation, the second auxiliary reflux pipe can be closed. When the quality of the ultrapure water deteriorates significantly, or the quality of the secondary pure water is significantly reduced due to the excessive quality of the primary pure water, or during the system trial operation phase, if the process water consumption is not affected, some or all of the reflux water can be refluxed further upstream through the second auxiliary reflux pipe in a short period of time.

[0040] Specifically, several flow sensors are installed in the first hybrid photolysis absorber, the second hybrid photolysis absorber, or other required locations to provide real-time feedback to the control unit on the amount of water to be treated in the first and second photolysis zones, as well as the flow conditions in areas requiring close attention. The control unit determines the total illumination and irradiation duration of the radiation sources in the first and second photolysis zones based on the online detection results and the feedback from the flow sensors, compared with the set water quality threshold and current radiation conditions, and thus determines the specific number of radiation sources to be activated, among other conditions. Taking the maximum illumination of all radiation sources activated as 100%, the illumination adjustment range of the first and second photolysis zones is between approximately 10% and 100%, preferably between 30% and 100%. Furthermore, the radiation sources can be grouped and controlled, for example, by dividing them into 2-8 groups, each with approximately 1-6 radiation sources, so that the radiation source groups rotate in operation. More preferably, they are divided into 4-8 groups, each with approximately 1-5 radiation sources. Increasing the number of radiation source groups and reducing the number of radiation sources within a single group allows for more precise control of the radiation dose. 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 .

[0041] Preferably, 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; and / or Determine the connection mode of the water outlet of the degassing unit based on the online detection result of the first sampling; and / or According to the online test results 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.

[0042] The present invention has at least the following beneficial effects: (1) The present invention adopts a two-stage purification device and process. The first-stage system processes the primary pure water to obtain secondary pure water. The second-stage 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.

[0043] (2) The purification equipment and process system of the present invention can meet the water quality requirements of semiconductor cutting-edge process water, providing an advanced ultrapure water purification technology for deep removal of multiple pollutants. It can achieve lower ultrapure water quality indicators such as total organic carbon, boron, trace metals and dissolved oxygen, meeting the higher standards of ultrapure water required by nano-process semiconductors. It also further refines the design of the hybrid photolysis absorber, solving the problems of the previous hybrid photolysis absorber producing oxygen byproducts in the polishing section and the hybrid photolysis absorber in the deep desalination section affecting the boron removal efficiency.

[0044] (3) The control unit, online detection unit, first reflux line (including its first auxiliary reflux line) and second reflux line (including its second auxiliary reflux line) 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 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 their auxiliary reflux, and controlling 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 stage system in an energy-saving and efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the structure of the first hybrid photodecomposer and the second hybrid photodecomposer of the present invention; Figure 2 This is a flow chart of the purification process of the present invention.

[0046] 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

[0047] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction 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 efforts are within the scope of protection of the present invention.

[0048] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0049] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0050] like Figure 1 and Figure 2 As shown, the present invention provides a second-stage purification device and purification process for ultrapure water. Specifically, the second-stage purification device includes a first-stage system and a second-stage system connected in sequence, wherein: (1) First-order system: The primary pure water is treated to obtain secondary pure water, including a desalination unit 11, a first hybrid photolysis absorber 12 and a degassing unit 13 connected in sequence. Specifically: (1.1) Desalination unit 11, including at least one of a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower; (1.2) First hybrid photodecomposition absorber 12, see 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); In the first treatment area 122, the positive adsorption layer 1221 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 1222 includes a boron absorber; The ion polishing layer 1223 includes a mixed ion exchanger having basic groups and acidic groups; 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 hybrid photolysis absorber 12 is below 3 μg / l, preferably less than 2 μg / l. The first photolysis zone 121 includes multiple 185 nm radiation light sources, for example, 1-25 radiation light sources, preferably 4-20 radiation light sources. The illumination intensity and irradiation duration of each radiation light source are independently adjustable. This allows the number of radiation light sources to be turned on and off based on 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 grouped and controlled, for example, divided into 2-8 groups, each group containing approximately 1-6 radiation light sources, so that the radiation light source groups can be rotated to operate.

[0051] (1.3) Degassing unit 13, including a 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.

[0052] (2) Second-order system: The secondary pure water is treated to obtain ultrapure water, comprising a membrane absorber 21, a second hybrid photolysis absorber 22 and a degassing ultrafiltration unit connected in sequence, specifically: (2.1) A membrane absorber 21, comprising a hydrogen-dissolving membrane and a hydrogen supply pipeline, is used to dissolve hydrogen in the secondary pure water to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.05-0.1 mg / l; (2.2) Second hybrid photodecomposer 22, see Figure 1, having a second photolysis zone 221 and a second treatment zone 222 downstream thereof, wherein in the direction of water flow, the second treatment zone 222 sequentially includes a catalytic reaction layer 2221 and a second ion polishing layer 2222, and 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), and more preferably 1:(2.5-20); 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 0.5 μg / l, preferably below 0.3 μg / l; the second photolysis zone 221 has several 185nm radiation light sources, for example 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 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 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. More preferably, they are 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 can more accurately regulate the radiation dose.

[0053] (2.3) The degassing ultrafiltration unit includes a membrane contact degassing device 23 and an ultrafiltration device 24 connected in sequence, which removes dissolved gases and microparticles in the residual water to sub-ppb level and nanometer level.

[0054] (3) Detection and control system: The detection and 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. (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 particulate matter analyzer, a boron analyzer, a silica analyzer, a resistivity meter, and a hydrogen peroxide analyzer; (3.2) A control unit, which determines the communication 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: (3.2.1) First-order system reflux method: 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 line; During 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; The first reflux line 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 returned to the inlet of the shallow desalination system 10; (3.2.2) Second-order system reflux method: 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 line; During normal operation, the second reflux ratio of the second reflux line is above 5%. The specific upper limit is determined based on test results, downstream water consumption, and equipment production capacity. Typically, 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.

[0055] The second return line further 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.

[0056] The first auxiliary return pipe and the second auxiliary return pipe are only conditionally started intermittently and quickly, and there may be no water flow in the auxiliary return pipes during the shutdown period.

[0057] (3.3) Several flow detectors are set in the first mixed photolysis absorber 12, the second mixed 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 and the flow conditions in the areas that need 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, and compares them 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.

[0058] Based on the second-stage purification equipment and purification process, the first hybrid photodecomposition absorber 12 and the second hybrid photodecomposition absorber 22 preferably adopt the same structure, including: A. a first housing and a plurality of radiation light sources, wherein the radiation light sources are encapsulated in a transparent hollow closed structure formed by the first housing to form a vacuum radiation cavity; The radiation source includes a VUV / UV low-pressure, high-intensity mercury vapor or a low-pressure, high-intensity amalgam arc discharge light source. The radiation source is connected to the control unit, which regulates the radiation dose of the radiation source based on the parameters of the water flow to be purified. Preferably, it includes 1-48 185nm radiation sources, more preferably 20-40 radiation sources, and the illumination intensity and exposure duration of each radiation source are independently adjustable. This allows the number of radiation sources 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 sources are used, the radiation sources can be grouped and controlled. For example, they can be divided into 2-8 groups, each with approximately 1-6 radiation sources, so that the radiation source groups rotate in operation. When more simple and precise control of the radiation dose is required, the number of radiation source groups can be increased, and the number of radiation sources within a single group can be reduced. Preferably, the radiation source groups are divided into 4-8 groups, each with approximately 1-5 radiation sources.

[0059] 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%; B. A second shell is arranged around the first shell. The second shell, the 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; 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.

[0060] C. Top cover, third shell and bottom wall. The top cover, third shell and 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. Preferably, the third shell is made of thermoplastic resin material polymerized by ethylene or propylene, or fiber-reinforced composite plastic.

[0061] 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. 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 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 outlet.

[0062] In comparison, although the internal and external structures are the same, the processing areas of the first hybrid photodecomposer and the second hybrid photodecomposer have different filling methods: In the first hybrid photodecomposition 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 photodecomposition absorber, the catalytic reaction layer and the ion polishing layer are arranged in the second processing zone from top to bottom.

[0063] In addition, the radiation doses in the first hybrid photodecomposition absorber and the second hybrid photodecomposition absorber can be the same or different. For example, the radiation dose in the first photodecomposition absorber is 300-800 mJ / cm 2 Adjust the radiation dose in the second photolysis zone to 200-900mJ / cm 2 adjust.

[0064] The purification process using the second-stage purification equipment includes the following steps: 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 pretreated by shallow desalination enters the desalination unit to further remove anions and cations to obtain deep desalted water; S1.2 Deep desalted water enters the first hybrid photolysis absorber and undergoes photolysis, positive adsorption, complexation and ion polishing in sequence to obtain quasi-secondary pure water; S1.3 Quasi-secondary pure water enters the degassing unit, where dissolved gases and volatiles are removed to obtain secondary pure water. The outlet water of the degassing unit is sampled for a first time and tested online. The control unit determines, based on the online test results, whether to connect the outlet of the degassing unit to the pure water storage tank for secondary purification treatment and / or to connect the outlet of the desalination unit to the inlet of the demineralization unit via the first reflux line for primary purification treatment. S2. Performing a second-stage purification process in a second-stage system to obtain ultrapure water from 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-charged water with a dissolved hydrogen concentration of 0.05-0.1 mg / l. S2.2 The hydrogen-charged water enters the second hybrid photolysis absorber and undergoes photolysis, catalytic reaction, and ion polishing 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. The water outlet of the degassing ultrafiltration unit is sampled for a second time and tested online. The control unit determines, based on the online test results, whether the water outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network, and / or connected to the pure water storage tank through a second reflux line for another second-stage purification treatment.

[0065] Specifically, a flow rate detector is installed upstream of the inlet pipes of at least the first and second hybrid photodecomposition absorbers to provide real-time feedback to the control unit on the volume of water to be treated in the first and second photodecomposition zones. The control unit determines the total illumination and irradiation duration of the radiation sources in the first and second photodecomposition zones based on the online detection results and the feedback from the flow rate detector, compared with the set water quality threshold and current radiation conditions, and thereby determines the specific number of radiation sources to be activated, among other conditions. Taking the maximum illumination of all radiation sources activated as 100%, the illumination adjustment range for the first and second photodecomposition zones is approximately 10-100%, preferably 30-100%. Furthermore, the radiation sources can be grouped and controlled, for example, by dividing them into 2-8 groups, each containing approximately 1-6 radiation sources, so that the radiation source groups rotate in operation. More preferably, the groups are divided into 4-8 groups, each containing approximately 1-5 radiation sources. Increasing the number of radiation source groups and reducing the number of radiation sources within a single group allows for more precise control of the radiation dose.

[0066] 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 .

[0067] The ultrapure water quality indicators obtained by the above purification process are as follows: 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.

[0068] 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 generally described below according to the process flow: 1) The primary pure water obtained from raw water treatment is passed into the continuous electric desalination system; 2) The produced water from the continuous electro-desalination system enters the first hybrid photolysis absorber through the inlet, flows sequentially through the first photolysis zone (from bottom to top), the sealed chamber at the top, the first reaction chamber (from top to bottom), and the water collection chamber at the bottom, before exiting the first hybrid photolysis absorber through the outlet. In the photolysis zone, ultraviolet radiation from the vacuum radiation chamber is absorbed by water molecules to produce hydroxyl radicals and superoxide radicals, inducing a chain reaction to generate a variety of highly oxidizing active substances. These react with residual dissolved pollutants in the water to be purified through addition or hydroxylation reactions, further followed by hydrogen abstraction or redox reactions, degrading dissolved organic matter in the water to form the first treated water. The core of the reaction is the hydroxyl radical (OH·). The OH· produced when the water is irradiated by 185nm ultraviolet light can oxidize organic matter into carbon dioxide, water, and intermediate products. After entering the sealed chamber, the first treated water flows through the first treatment zone, first passing through the first positive adsorption zone, which removes low-molecular-weight acidic organic matter from the water after oxidation by 185nm UV radiation. It then flows through the second complexation reaction zone. Weakly ionic H₃BO₃ is efficiently removed in the positive adsorption zone over a short lifespan, while the complexation reaction zone allows for long-term, deep reduction, even reaching a high initial leakage concentration of less than 0.5 ng / L. However, at the same time, some high-molecular-weight polymers will precipitate from the boron absorbent zone, causing a slight increase in TOC concentration and a slight decrease in water resistivity. Therefore, when the deboronized water flows through the ion polishing zone, it effectively absorbs the micro-contaminants released by the NMDG-based adsorbent, controlling the increased TOC concentration to 1 μg / L or even lower, and significantly improving the water resistivity. The ion polishing zone and the complexation reaction zone are filled with different absorbent materials and are closely connected. Therefore, after passing through the first hybrid photodecomposer, low-molecular-weight organic matter can be deeply degraded and weakly ionized impurities can be further removed. It also absorbs high-molecular-weight organic matter produced by the complexation reaction and increases resistivity. Within the first hybrid photodecomposer, all water-contacting surfaces and water-flowing devices, including the inlet pipe, chamber, baffles, channels, and water collector, are constructed from polymer or quartz, unlike the alloy steel used in traditional reactors and exchange towers. This allows the entire device to be completely demetallized or metal-minimized. Furthermore, the highly integrated design of the hybrid photodecomposer not only saves the floor space of at least two devices, but also improves radiation efficiency thanks to the light-shielding and reflective structural design of the first reaction chamber and the protective measures of filling the vacuum radiation chamber with inert gas to reduce light attenuation. The shortened transmission distance between devices in the transition zone effectively reduces the accumulation of micro-contaminants precipitated from the pipe material, resulting in a significantly higher removal efficiency even in the ultra-trace detection range.

[0069] 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 is treated to form secondary pure water. The membrane degasser outlet forms a closed loop with the first return pipeline leading to the inlet of the demineralization unit, and the pipeline is connected to the pure water storage tank between the first-order system and the second-order system. 4) A second-stage system ultrapurifies the secondary pure water from the pure water storage tank. The secondary pure water flows through a membrane absorber, which contains a built-in hydrogen-dissolving membrane. This membrane consists of densely packed tubular hollow fibers. The fiber tubes are made of a hydrophobic material, preventing water molecules from passing through the tube walls, while gas molecules can. Hydrogen is pressure-generated into the tubes, evenly transferring the hydrogen into the water, achieving liquid-phase absorption of the gas.

[0070] 5) The produced water from the membrane absorber enters the second hybrid photolysis absorber through the inlet, flowing sequentially through the second photolysis zone (from bottom to top), the sealed chamber at the top, the second reaction chamber (from top to bottom), and the water collection chamber at the bottom, before exiting the second hybrid photolysis absorber through the outlet. When the hydrogen-dissolved water flows through the catalytic reaction zone of the second reaction chamber, the decomposition of hydrogen peroxide produces oxygen on the catalyst surface. Because the water is rich in hydrogen, hydrogen is adsorbed onto the catalyst surface. At the active sites on the catalyst surface, the adsorbed atomic oxygen is preferably hydrogenated to adsorbed hydroxyl groups, and the adsorbed hydroxyl groups are further hydrogenated to water, resulting in the desorption of the product water from the catalyst surface. The hydrogen oxidation reaction within the catalyst framework is also effective in removing dissolved oxygen from the water. The water then passes through the ion polishing zone to further remove trace metals and increase resistivity.

[0071] 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 gases generated or remaining in the second hybrid photolysis absorber using membrane degassing technology with a combined nitrogen and vacuum purge method, 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 number concentration of particles larger than 0.05μm is <0.1pcs / mL).

[0072] Example 1 A second-stage purification device and purification process for ultrapure water, comprising a first-stage system and a second-stage system connected in sequence, wherein: (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: (1.1) Desalination unit, including a continuous electric desalination device, a mixed ion exchange tower, and a composite ion exchange tower connected in sequence; (1.2) First hybrid photodecomposer, see attached Figure 1, having a first photolysis zone and a first treatment zone downstream thereof, wherein 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; 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 absorber; The ion polishing layer includes a mixed ion exchanger having basic groups and acidic groups; The radiation dose in the first photolysis zone was 762 mJ / cm 2 The illumination and irradiation duration of each radiation light source can be adjusted independently. The radiation light sources can also be controlled in groups, with 20 radiation light sources divided into 5 groups, each with 4 radiation light sources.

[0073] (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, and the TOC mass concentration of the water body is less than 2.5μg / l.

[0074] (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: (2.1) A membrane absorber, comprising a hydrogen-dissolving membrane and a hydrogen supply line, is used to dissolve hydrogen in the secondary pure water to obtain hydrogen-filled water with a dissolved hydrogen concentration of 0.08 ± 0.01 mg / l; (2.2) a second hybrid photolysis absorber, comprising a second photolysis zone and a second treatment zone downstream thereof, wherein the second treatment zone comprises a catalytic reaction layer and an ion polishing layer in the direction of water flow, and the thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:2.5; The radiation dose in the second photolysis zone was 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.

[0075] (2.3) Degassing ultrafiltration unit, including a membrane contact degassing device and an ultrafiltration device connected in sequence, to remove dissolved gases and microparticles in the residual water to sub-ppb level and nanometer level.

[0076] The purification process using the second-stage purification equipment includes the following steps: 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 pretreated by shallow desalination enters the desalination unit to further remove anions and cations to obtain deep desalted water; S1.2 Deep desalted water enters the first hybrid photolysis absorber and undergoes photolysis, positive adsorption, complexation and ion polishing in sequence to obtain quasi-secondary pure water; 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; S2. Performing a second-stage purification process in a second-stage system to obtain ultrapure water from 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-charged water with a dissolved hydrogen concentration of 0.08±0.01mg / l. S2.2 The hydrogen-charged water enters the second hybrid photolysis absorber and undergoes photolysis, catalytic reaction, and ion polishing 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, which is then sampled and tested.

[0077] Example 2 The difference between this embodiment and Example 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 water outlet of the degassing unit is sampled and tested, and the TOC mass concentration of the water body is less than 2.7 μg / l. In the second-order system, the thickness ratio of the catalytic reaction layer and the ion polishing layer is 1:9.

[0078] Example 3 The difference between this embodiment and Example 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 2.8 μg / l. In the second-order system, the thickness ratio of the catalytic reaction layer and the ion polishing layer is 1:20.

[0079] Example 4 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 pipeline is set as follows: The detection and control system also includes a flow detector, a first reflux line within the first-order system, and a second reflux line within 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 volume of the first reflux line to the volume of water entering the pure water storage tank from the outlet of the degassing unit.

[0080] 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 consumption.

[0081] The reflow process steps specifically include: In step 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, and the outlet water of the degassing unit is connected to the pure water storage tank according to the first reflux ratio set by the first reflux pipeline to enter 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.

[0082] In step 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 and tested, and the outlet of the degassing ultrafiltration unit is connected to the ultrapure water supply network according to the second reflux ratio set by the second reflux line, and is connected to the pure water storage tank through the second reflux line for secondary purification treatment again.

[0083] Example 5 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 conveys 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 conveys 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 conveys 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.

[0084] Example 6 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. The purification process using the second-stage purification equipment further includes the following steps: (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 according to the online test results and dynamically adjusts it between 10-60%. (2) The ultrapure water flowing out of the degassing ultrafiltration unit is sampled for the second time and tested online. The control unit determines the second reflux ratio of the degassing ultrafiltration unit outlet at about 50% based on the online test results and dynamically adjusts it.

[0085] Flow rate sensors are installed upstream of the inlet pipes of the first and second hybrid photodecomposition absorbers, providing real-time feedback to the control unit on the volume of water to be treated in the first and second photodecomposition zones. Based on the online detection results and the flow rate sensor feedback, the control unit determines the total illumination intensity and duration of the radiation sources in the first and second photodecomposition zones, comparing them with the set water quality threshold and current radiation conditions. This information, in turn, determines the specific number of radiation sources to be activated, among other conditions. The first and second photodecomposition zones are equipped with 40 185nm radiation sources, divided into eight groups of five, each with independently adjustable illumination intensity and duration. One group can be added or removed from the eight groups based on signals from the control unit. After stabilization, the TOC concentration in the effluent from the first-order system's degassing unit is less than 2 μg / l.

[0086] Comparative Example 1 This comparative example is based on the configuration of invention CN115636557B and differs from Example 2 in that only a complex reaction layer and a positive adsorption layer are sequentially provided in the first-order system, with a thickness ratio of approximately 3:2; In the second-order system, a positive adsorption layer, a complex reaction layer, and an ion polishing layer are arranged in sequence, with a thickness ratio of approximately 1:2:3.

[0087] Comparative Example 2 This comparative example is derived from invention CN115626745B. Compared with Example 2, 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 provided in the first-stage treatment is 1:2:3.

[0088] When water flow is continuously maintained for two days, the output water body detection data of each embodiment and comparative example are shown in Table 1: Table 1 Output water body detection data of embodiment and comparative example

[0089] In the embodiment of the present invention, the pretreated primary pure water passes through the desalination unit (continuous electrolytic desalination system EDI) and enters the first photolysis zone. 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. These substances undergo addition reactions or hydroxylation reactions with residual soluble pollutants in the water to be purified, and then undergo hydrogen abstraction reactions or redox reactions to degrade soluble organic matter in the water and convert them into carbon dioxide, water, and intermediate products.

[0090] The water flows through the positive adsorption zone, where low-molecular-weight acidic organic matter is removed from the water after radiation oxidation. It then flows through the complexation reaction zone, where H₃BO₃ is deeply removed. However, at the same time, some high-molecular-weight polymers precipitate in the complexation reaction zone, causing a slight increase in TOC concentration and a certain decrease in resistivity. Therefore, when the deboronized water flows through the ion polishing zone, it effectively adsorbs the micro-contaminant electrolytes released by the NMDG-based adsorbent, controlling the increased TOC concentration to a low level and significantly improving the water's resistivity. The ion polishing zone and the complexation reaction zone are filled with different absorbent materials and are closely connected. Therefore, after passing through the first hybrid photodecomposition absorber, low-molecular-weight organic matter is deeply degraded and weakly ionized impurities are removed. It also absorbs high-molecular-weight organic matter produced by complexation reactions and increases resistivity. Inside the first hybrid photodecomposition absorber, all water-contacting surfaces and water-passing devices, including the inlet pipe, cavity, baffles, channels, and water collector, are constructed from polymer or quartz, unlike the alloy steel used in traditional reactors and exchange towers. This allows the entire device to be completely demetallized or metal-minimized. The treated water from the first hybrid photodecomposition absorber then passes through a degassing unit to remove dissolved oxygen (including dissolved gases and volatile substances) in the water and resin. This treatment results in secondary pure water, which is preferably formed into a closed loop with the water flowing into the demineralization unit. The remaining secondary pure water is stored in a pure water storage tank.

[0091] It can be seen that the first-order system integrates the basic desalination guarantee link, photolysis absorption enhancement treatment link and degassing link, which can obtain high-quality secondary pure water. In addition, combined with detection methods and reflux design, it can control the quality and flow of secondary pure water more efficiently.

[0092] In a second-stage system, secondary pure water first flows through a membrane absorber, which houses a gas transfer membrane. The membrane consists of densely packed tubular hollow fibers made of hydrophobic material, preventing water molecules from passing through the tube walls while allowing gas molecules to pass through. Hydrogen is purged through the tubes, evenly transferring the hydrogen into the water, achieving liquid-phase absorption of the gas. The gas transfer membrane effectively increases the hydrogen concentration in the water. When the hydrogen-dissolved water flows through the catalytic reaction zone of the second hybrid photolysis absorber, the metal catalyst, preferably a supported metal catalyst, forms a positively charged adsorbent matrix, effectively adsorbing low-molecular-weight acidic organic compounds produced by UV oxidation. This catalyst also decomposes H₂O₂, reducing the decomposition byproduct, O₂, to H₂O. A suitable amount of H₂ further catalyzes the reduction of DO in the water to H₂O on the surface of the supported metal catalyst matrix. This is particularly beneficial for rapidly reducing the DO value of the output ultrapure water to below 0.3 ppb. The ion polishing zone then further removes trace metals and increases resistivity. Therefore, the second hybrid photolysis absorber can deeply remove, absorb, and degrade trace metal ions, weakly ionized impurities, dissolved oxygen, and low-molecular-weight organic matter to extremely low limits of ppq, ppt, and ppb, respectively. It also controls the free radical complex oxidants produced during the catalytic reduction photolysis process to sub-μg / L levels. The treated water from the second hybrid photolysis absorber is then degassed, and trace dissolved gases generated or remaining in the second hybrid photolysis absorber are efficiently removed using membrane degassing technology with a combined nitrogen and vacuum purge, further reducing residual dissolved oxygen. Finally, terminal ultrafiltration removes all bacteria and particulate impurities.

[0093] It can be seen that the second-order system integrates the hydrogen dissolution and deoxygenation, photolysis and absorption enhanced treatment and degassing ultrafiltration links, 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 more efficiently and effectively to meet the water needs of downstream semiconductor processes.

[0094] 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.

[0095] Although preferred embodiments of the present invention have been described, further changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are understood. Therefore, the present invention is intended to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention. Obviously, various changes and modifications may be made to the present invention by those skilled in the art 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 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 ; 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; 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 .

2. The second-stage purification device according to claim 1, characterized in that: 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; The thickness ratio of the positive adsorption layer, the complex reaction layer and the ion polishing layer is (1-4): (8-10): (1-4); In the second treatment zone, the catalytic reaction layer includes a supported metal nanoparticle catalyst; the ion polishing layer includes a mixed ion exchanger with basic groups and acidic groups respectively; The thickness ratio of the catalytic reaction layer to the ion polishing layer is 1:(2.5-20).

3. The second-stage purification device according to claim 2, 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 third 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; 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.

4. The second-stage purification device according to any one of claims 1 to 3, 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-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.

5. The second-stage purification device according to claim 4, 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.

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

7. The second-stage purification device according to claim 5 or 6, 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.

8. A purification process using the second-stage purification device according to any one of claims 1 to 7, 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.

9. The purification process according to claim 8, 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.

10. The purification process according to claim 9, 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; and / or Determine the connection mode of the water outlet of the degassing unit according to the online detection result of the first sampling; and / or 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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