System and method for preparing high-uniformity quartz glass

Abstract

The invention relates to a system and a method for preparing high-uniformity quartz glass, and belongs to the technical field of quartz. The system for preparing the high-uniformity quartz glass comprises a multi-stage dynamic mixer which comprises a heating device, a Venturi tube, a static spiral mixer and a metal filtering membrane which are connected in sequence, and the heating device comprises a first heating device, a second heating device and a third heating device; the combustor comprises a central material pipe, a first isolation nitrogen cavity, a first epoxy core through pipe, an inner hydrogen cavity, an interlayer material pipe cavity, a second isolation nitrogen cavity, a second epoxy core through pipe, a third epoxy core through pipe, an outer hydrogen cavity, a first-layer peripheral oxygen cavity, a second-layer peripheral oxygen cavity and a third-layer peripheral oxygen cavity which are coaxially arranged from inside to outside. And the output end of the metal filter membrane is connected with the input end of the burner. The method is used for preparing high-purity quartz glass and is particularly suitable for the semiconductor and optical fields.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of quartz, and particularly relates to a system for preparing high-uniformity quartz glass and a method thereof. BACKGROUND

[0002] Quartz glass occupies an irreplaceable position in key fields such as semiconductor lithography systems and deep ultraviolet optical elements due to its high purity, low expansion coefficient and excellent optical performance, and the advantages and disadvantages of its preparation process are directly related to product performance and application effect. At present, the traditional chemical vapor deposition (CVD) method is the mainstream way to prepare quartz glass. This method usually uses silicon tetrachloride (SiCl4) as raw material, mixes it with oxygen or water vapor, and then performs gas phase reaction to generate silicon dioxide particles under high temperature conditions. These particles are sintered after deposition to form high-purity quartz glass, which is widely used in the fields of semiconductors and optical elements. The advantages of the SiCl4 process are obvious. Not only is the raw material abundant, but also the raw material purification technology and CVD deposition process have been very mature after years of development, and excellent products can be stably produced. However, this process also has problems that cannot be ignored. Chlorine pollution occurs during the reaction process, and the production equipment is also severely corroded, which is contrary to the current demand for green production and long-term stable operation of equipment.

[0003] To solve the problems of chlorine pollution and equipment corrosion in the traditional SiCl4 process, octamethylcyclotetrasiloxane (D4), a chlorine-free silicon source, has gradually entered the industry's field of vision and become a new raw material for preparing quartz glass. As a chlorine-free silicon source, D4 can avoid chlorine-related environmental pollution from the source, and has higher deposition efficiency than the SiCl4 process, so it has significant environmental and efficiency advantages. Therefore, in recent years, the green process using D4 as raw material has gradually emerged. However, the D4 process also faces some challenges. Its raw material purification process is more complex, and the process control during the deposition process is also more difficult. Moreover, there are three major technical bottlenecks in actual application, which seriously affect the preparation of high-uniformity quartz glass. First, the raw material reaction is not sufficient. Due to the uneven mixing of D4 and oxygen, local incomplete combustion is easy to occur, which in turn forms bubble defects in the deposition process, damaging the optical uniformity of the quartz glass. Second, the carbon residue is too high. The methyl groups contained in the D4 molecule are easy to generate CO or CO2 during combustion. If the oxygen supply is insufficient, carbon impurities will remain in the quartz glass in the form of nanoparticles, increasing the ultraviolet absorption of the glass and failing to meet the performance requirements of deep ultraviolet optical elements. Finally, the quartz glass is not uniform. The traditional single-point feeding method makes the deposition rate uneven, and the prepared quartz glass has a radial density gradient, which adversely affects the performance stability of the subsequent quartz products.

[0004] For the technical bottleneck of D4 process, although the existing technology has improvement attempts, it cannot fundamentally solve the problem. Some schemes can improve the purity of raw materials by multi-stage rectification purification of D4, which can only reduce the bubble problem caused by impurities in raw materials to a certain extent, but cannot solve the problem of insufficient reaction caused by factors such as incomplete mixing and incomplete reaction path on the reaction kinetics level, and the bubble defect is still difficult to completely eliminate.

[0005] Therefore, it is urgent to develop a new CVD preparation process and device, which can realize sufficient reaction of raw materials, low carbon content and uniform deposition, so as to break through the technical bottleneck of the existing technology and provide a reliable way for stable preparation of high-uniformity quartz glass. SUMMARY

[0006] To solve the above technical problems, the present application provides a system and method for preparing high-uniformity quartz glass, which is prepared by a one-step synthesis method of hydrogen / oxygen combustion driven chemical vapor deposition, and is especially suitable for the fields of semiconductors and optics.

[0007] The first object of the present application is to provide a system for preparing high-uniformity quartz glass, which comprises:

[0008] The multi-stage dynamic mixer comprises a heating device, a Venturi tube, a static spiral mixer and a metal filter membrane connected in sequence, wherein the heating device comprises a first heating device, a second heating device and a third heating device; the output end of the first heating device is connected with the input end of the second heating device; the output ends of the second heating device and the third heating device are respectively connected with the input end of the Venturi tube;

[0009] The burner comprises a central tube, a first isolation nitrogen cavity, a first oxygen core pipe, an inner hydrogen cavity, a sandwich tube cavity, a second isolation nitrogen cavity, a second oxygen core pipe, a third oxygen core pipe, an outer hydrogen cavity, a first peripheral oxygen cavity, a second peripheral oxygen cavity and a third peripheral oxygen cavity, which are arranged coaxially from inside to outside; a plurality of central tubes are arranged in the first isolation nitrogen cavity in a ring shape; a plurality of first oxygen core pipes are arranged between the first isolation nitrogen cavity and the inner hydrogen cavity in a ring shape; a plurality of second oxygen core pipes and a plurality of third oxygen core pipes are arranged between the second isolation nitrogen cavity and the outer hydrogen cavity in a ring shape; and the second oxygen core pipe is close to the second isolation nitrogen cavity; and the third oxygen core pipe is close to the outer hydrogen cavity.

[0010] The output end of the metal filter membrane is connected with the input end of the burner.

[0011] In an embodiment of the present application, the central tube is arranged in a central tube shell.

[0012] The first isolation nitrogen cavity is arranged in a first isolation nitrogen cavity shell.

[0013] The first epoxy core pipe is arranged in a first epoxy core pipe shell.

[0014] The inner hydrogen cavity is arranged in an inner hydrogen cavity shell.

[0015] The interlayer material pipe cavity is arranged in an interlayer material pipe cavity shell.

[0016] The second isolation nitrogen cavity is arranged in a second isolation nitrogen cavity shell.

[0017] The second epoxy core pipe is arranged in a second epoxy core pipe shell.

[0018] The third epoxy core pipe is arranged in a third epoxy core pipe shell.

[0019] The outer hydrogen cavity is arranged in an outer hydrogen cavity shell.

[0020] The first peripheral oxygen cavity is arranged in a first peripheral oxygen cavity shell.

[0021] The second peripheral oxygen cavity is arranged in a second peripheral oxygen cavity shell.

[0022] The third peripheral oxygen cavity is arranged in a third peripheral oxygen cavity shell.

[0023] A second object of the present application is to provide a method for preparing high-uniformity quartz glass, which is implemented by using the system for preparing high-uniformity quartz glass.

[0024] S1, preheating the carrier gas by the first heating device, and blowing octamethylcyclotetrasiloxane into the second heating device for gasification to obtain a mixed gas;

[0025] S2, preheating the oxygen by the third heating device, and mixing the preheated oxygen with the mixed gas obtained in S1 in a Venturi tube for primary mixing, and then mixing in a static spiral mixer for secondary mixing, and finally filtering through a metal filter membrane to obtain a premixed reaction gas;

[0026] S3, passing the premixed reaction gas obtained in S2 into the center pipe and the interlayer material pipe cavity of the burner at a first preset flow rate and a second preset flow rate respectively; meanwhile, passing nitrogen into the first isolation nitrogen cavity and the second isolation nitrogen cavity at a third preset flow rate, passing hydrogen into the inner hydrogen cavity and the outer hydrogen cavity at a fourth preset flow rate, passing oxygen into the first epoxy core pipe, the second epoxy core pipe and the third epoxy core pipe at a fifth preset flow rate, and passing oxygen into the first peripheral oxygen cavity, the second peripheral oxygen cavity and the third peripheral oxygen cavity, and the flow rate of the oxygen decreases along the radial direction of the burner, and depositing on the quartz supporting platform to obtain high-uniformity quartz glass.

[0027] In one embodiment of the present application, in S1, the carrier gas is selected from nitrogen, argon or helium;

[0028] The preheating temperature is 150-250℃;

[0029] The gasification temperature is 150-250℃;

[0030] The volume ratio of octamethylcyclotetrasiloxane to carrier gas is 1:(4-8).

[0031] In one embodiment of the present application, in S2, the preheating temperature is 150-250℃;

[0032] The mass ratio of octamethylcyclotetrasiloxane to oxygen in the mixed gas is (5-10):1.

[0033] In one embodiment of the present application, in S2, the secondary mixing time is at least 0.5s;

[0034] The pore size of the metal filter membrane is 5-100nm.

[0035] In one embodiment of the present application, in S3, the first preset flow rate and the second preset flow rate are independently 10-50g / min, and the ratio of the first preset flow rate to the second preset flow rate is (1-2):1; by controlling the first preset flow rate and the second preset flow rate, the flow rate of the premixed reaction gas of each nozzle can be adjusted to control the deposition rate deviation within a range of ≤±2%; at the same time, the first preset flow rate and the second preset flow rate affect the density distribution of the raw material, thereby affecting the final refractive index distribution and uniformity of the product.

[0036] The third preset flow rate is 10-50L / min; nitrogen is used as the isolation protective gas to isolate the premixed reaction gas (raw material) and oxygen (reaction gas);

[0037] The fourth preset flow rate is 300-700L / min;

[0038] The fifth preset flow rate is 100-300L / min; by controlling the flow rates of hydrogen and oxygen, the stability of the flame and the length of the high-temperature zone are ensured.

[0039] In one embodiment of the present application, in S3, the oxygen flow rates of the one-layer peripheral oxygen cavity, the two-layer peripheral oxygen cavity and the three-layer peripheral oxygen cavity are 30-40L / min, 20-25L / min and 10-15L / min, respectively, to form a radial oxygen-rich gradient.

[0040] In one embodiment of the present application, in S3, the deposition rate is 1 mm / h-3 mm / h, and the flame temperature is 1400℃-2000℃.

[0041] In one embodiment of the present application, in S3, the deposition process, the rotation speed of the quartz supporting platform is 5r / min-20r / min, the stroke of the radial reciprocating movement is 20mm-50mm, and the frequency is 0.005Hz-0.05Hz.

[0042] The technical solution of the present application has the following advantages compared with the prior art:

[0043] (1) The preparation method of the present application realizes the molecular-level uniform dispersion of octamethylcyclotetrasiloxane, carrier gas and oxygen through a multi-stage dynamic mixer, which can improve the reaction efficiency of octamethylcyclotetrasiloxane to achieve complete reaction, thereby inhibiting bubble generation; after the pre-mixed reaction gas enters the reaction zone (i.e. after the gas is sprayed out from the end face of the burner, the reaction occurs at a short distance from the end face), reaction points will be formed simultaneously "inside" and "outside", thereby improving the reaction rate and conversion rate of octamethylcyclotetrasiloxane, ensuring that it can be fully reacted before reaching the deposition surface after being sprayed out of the raw material outlet; at the same time, by setting an outer oxygen cavity around the burner to create an oxygen-rich combustion environment, the complete oxidation of the methyl groups in the octamethylcyclotetrasiloxane molecules can be promoted, further ensuring the reaction completeness and reducing the probability of bubble generation.

[0044] (2) The preparation method of the present application optimizes the single raw material outlet mode to a double-zone outlet structure of the center material pipe and the interlayer material pipe cavity through special design of the burner, wherein the center material pipe adopts an array-type nozzle design, which can effectively avoid the focusing of raw materials on a single beam, significantly increase the distribution area of raw materials in the horizontal direction, thereby improving the uniformity of the distribution of the material points, making the distribution of silicon dioxide more uniform, reducing the difference in surface density distribution, and ultimately improving the optical uniformity of the quartz glass; at the same time, through the cooperation of the honeycomb array center material pipe and the annular interlayer material pipe cavity, three-dimensional uniform distribution of octamethylcyclotetrasiloxane vapor in the reaction zone is realized, and the density gradient of the quartz glass is eliminated.

[0045] (3) The preparation method of the present application can ensure that the generated silicon dioxide is uniformly distributed on the entire quartz supporting platform through the special distributed feeding design of the burner and the three-dimensional movement (rotation and radial reciprocating movement) of the quartz supporting platform, thereby solving the problem of surface density distribution gradient, making the overall silicon dioxide bubble-free and having a small horizontal density gradient, and ultimately making the prepared quartz glass have excellent optical uniformity.

[0046] (4) The preparation method of the application first improves the uniformity of the mixture of octamethylcyclotetrasiloxane vapor, oxygen and carrier gas by three-stage premixing, so that the bubble density can be controlled between 0.5 / 100kg-1.5 / 100kg; at the same time, the carbon residue is <100ppb by adopting multi-channel oxygen-enriched combustion, which meets the requirement of <0.5ppm of total metal impurities of semiconductor-grade quartz glass; in addition, the radial density difference of quartz glass is reduced by means of distributed feeding and three-dimensional motion trajectory design, so that the refractive index uniformity of quartz glass with a diameter of 600mm reaches Δn≤4×10 -6 , which is suitable for precision optical element processing. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments of the application and in conjunction with the drawings, in which:

[0048] Fig. 1 The schematic diagram of the system for preparing high-uniformity quartz glass of the application;

[0049] Fig. 2 The schematic diagram of the burner of the application;

[0050] BRIEF DESCRIPTION OF DRAWINGS: 1-center material pipe shell, 2-center material pipe, 3-one isolation nitrogen cavity, 4-one isolation nitrogen cavity shell, 5-one ring oxygen core pipe, 6-one ring oxygen core pipe shell, 7-inner hydrogen cavity, 8-inner hydrogen cavity shell, 9-interlayer material pipe cavity, 10-interlayer material pipe cavity shell, 11-two isolation nitrogen cavities, 12-two isolation nitrogen cavity shells, 13-two ring oxygen core pipes, 14-two ring oxygen core pipe shells, 15-three ring oxygen core pipes, 16-three ring oxygen core pipe shells, 17-outer hydrogen cavity, 18-outer hydrogen cavity shell, 19-one layer of peripheral oxygen cavity, 20-one layer of peripheral oxygen cavity shell, 21-two layers of peripheral oxygen cavities, 22-two layers of peripheral oxygen cavity shells, 23-three layers of peripheral oxygen cavities, 24-three layers of peripheral oxygen cavity shells. DETAILED DESCRIPTION

[0051] The application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the application and implement it. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. It should be understood that the specific embodiments are only used to explain the application, but the embodiments are not limited to the application.

[0052] In the application, unless otherwise specified, the technical and scientific terms used in the application are the same as the meanings commonly understood by the persons skilled in the art belonging to the technical field of the application.

[0053] In the present application, the term "and / or" used in the present application includes any and all combinations of one or more associated listed items, unless otherwise specified.

[0054] In the present application, unless otherwise specified, the experimental methods used in the embodiments of the present application are conventional methods, and the materials, reagents, etc. used are commercially available, unless otherwise specified.

[0055] In the present application, unless otherwise specified, the static spiral mixer used in the present application is a static spiral mixer that generates strong spiral flow through staggered guide vanes to further mix the premixed reaction gas.

[0056] Example 1

[0057] Referring to Figs. 1-2 As shown in the figure, a system for preparing high-uniformity quartz glass includes:

[0058] The multi-stage dynamic mixer includes a heating device, a Venturi tube, a static spiral mixer, and a metal filter membrane connected in sequence. The heating device includes a first heating device, a second heating device, and a third heating device. The output end of the first heating device is connected to the input end of the second heating device. The output ends of the second heating device and the third heating device are respectively connected to the input end of the Venturi tube.

[0059] The burner includes a central tube 2, an isolation nitrogen cavity 3, an epoxy core passage tube 5, an inner hydrogen cavity 7, a sandwich tube cavity 9, a double isolation nitrogen cavity 11, a double epoxy core passage tube 13, a triple epoxy core passage tube 15, an outer hydrogen cavity 17, an outer peripheral oxygen cavity 19, a double outer peripheral oxygen cavity 21, and a triple outer peripheral oxygen cavity 23 arranged coaxially from inside to outside. A plurality of central tubes 2 are arranged in a ring shape in the isolation nitrogen cavity 3. A plurality of epoxy core passage tubes 5 are arranged in a ring shape between the isolation nitrogen cavity 3 and the inner hydrogen cavity 7. A plurality of double epoxy core passage tubes 13 and a plurality of triple epoxy core passage tubes 15 are arranged in a ring shape between the double isolation nitrogen cavity 11 and the outer hydrogen cavity 17. The double epoxy core passage tube 13 is close to the double isolation nitrogen cavity 11, and the triple epoxy core passage tube 15 is close to the outer hydrogen cavity 17.

[0060] The central tube 2 is arranged in the central tube shell 1. The central tube 2 is arranged in a cross distribution (2x2) with an inner diameter of 1.8 mm and a tube center spacing of 5 mm.

[0061] The isolation nitrogen cavity 3 is arranged in the isolation nitrogen cavity shell 4. The isolation nitrogen cavity 3 has an inner diameter of 10 mm, and the isolation nitrogen cavity shell 4 has a wall thickness of 2 mm.

[0062] The epoxy core passage tube 5 is arranged in the epoxy core passage tube shell 6. The epoxy core passage tube 5 is uniformly distributed on the 1 / 2 center ring line of the inner hydrogen cavity 7.

[0063] The inner hydrogen cavity 7 is arranged in the inner hydrogen cavity shell 8; the distance between the inner hydrogen cavity shell 8 and the isolation nitrogen cavity shell 4 is 10 mm, and the wall thickness of the inner hydrogen cavity shell 8 is 2 mm;

[0064] The sandwich pipe cavity 9 is arranged in the sandwich pipe cavity shell 10; the distance between the sandwich pipe cavity shell 10 and the inner hydrogen cavity shell 8 is 2 mm, and the wall thickness of the sandwich pipe cavity shell 10 is 2 mm

[0065] The second isolation nitrogen cavity 11 is arranged in the second isolation nitrogen cavity shell 12; the distance between the second isolation nitrogen cavity shell 12 and the sandwich pipe cavity shell 10 is 2 mm, and the wall thickness of the second isolation nitrogen cavity shell 12 is 2 mm.

[0066] The second epoxy core pipe 13 is arranged in the second epoxy core pipe shell 14; the second epoxy core pipe 13 is uniformly distributed on the 1 / 3 center ring line of the outer hydrogen cavity 17;

[0067] The third epoxy core pipe 15 is arranged in the third epoxy core pipe shell 16; the third epoxy core pipe 15 is uniformly distributed on the 2 / 3 center ring line of the outer hydrogen cavity 17;

[0068] The inner diameter of the oxygen core pipe is 5 mm, and the wall thickness is 1 mm;

[0069] The outer hydrogen cavity 17 is arranged in the outer hydrogen cavity shell 18; the distance between the outer hydrogen cavity shell 18 and the second isolation nitrogen cavity shell 12 is 30 mm; the wall thickness of the outer hydrogen cavity shell 18 is 2 mm;

[0070] The first peripheral oxygen cavity 19 is arranged in the first peripheral oxygen cavity shell 20; the distance between the first peripheral oxygen cavity shell 20 and the outer hydrogen cavity shell 18 is 3 mm, and the wall thickness is 4 mm;

[0071] The second peripheral oxygen cavity 21 is arranged in the second peripheral oxygen cavity shell 22; the distance between the second peripheral oxygen cavity shell 22 and the first peripheral oxygen cavity shell 20 is 3 mm, and the wall thickness is 4 mm;

[0072] The third peripheral oxygen cavity 23 is arranged in the third peripheral oxygen cavity shell 24; the distance between the third peripheral oxygen cavity shell 24 and the first peripheral oxygen cavity shell 22 is 3 mm, and the wall thickness is 4 mm;

[0073] The output end of the metal filter membrane is connected to the input end of the combustor.

[0074] Example 2

[0075] The method for preparing high-uniformity quartz glass in this embodiment is implemented by using the system for preparing high-uniformity quartz glass in Example 1, and specifically includes the following steps:

[0076] S1, octamethylcyclotetrasiloxane (D4) with a purity of 99.5% is subjected to two batch rectifications by a double-tower rectification device to obtain liquid octamethylcyclotetrasiloxane with a purity of 99.99%.

[0077] S2, nitrogen is preheated to 180℃ by a first heating device, and octamethylcyclotetrasiloxane with a mass flow of 30g / min is blown into a second heating device for gasification at 180℃ to obtain a mixed gas with a volume ratio of octamethylcyclotetrasiloxane to carrier gas of 1:8;

[0078] S3, oxygen is preheated to 180℃ by a third heating device, and is introduced into a Venturi tube together with the mixed gas for primary mixing, and then is introduced into a static spiral mixer for secondary mixing for 5s, and finally is filtered through a metal nickel filter membrane with a pore size of 8nm to obtain a premixed reaction gas with a mass ratio of octamethylcyclotetrasiloxane to oxygen of 10:1;

[0079] S4, the premixed reaction gas is split according to a volume ratio of 2:1, is evenly distributed through a gas pipeline, and is introduced into the central tube and the interlayer tube cavity of the burner at a flow rate of 20g / min and 10g / min, respectively; at the same time, nitrogen gas with a total flow rate of 20L / min (1:1) is introduced into the first and second isolation nitrogen cavities through the gas pipeline; hydrogen gas with a total flow rate of 400L / min (1:1) is introduced into the inner and outer hydrogen cavities; oxygen gas with a total flow rate of 200L / min (1:1) is introduced into the first, second and third oxygen core pipes; oxygen gas with flow rates of 30L / min, 20L / min and 10L / min is introduced into the first, second and third peripheral oxygen cavities, respectively, and is deposited on a quartz support platform at a deposition rate of 2mm / h, a flame temperature of 1700℃, and a micro-positive pressure in the reaction cavity; during the deposition process, the quartz support platform rotates and moves radially reciprocally through a planetary rotation mechanism at a rotation speed of 15r / min, a radial reciprocating stroke of ±40mm, and a frequency of 0.03Hz; after 10 days of deposition, a quartz glass with a diameter of 600mm, a height of 290mm, and a single weight of about 180kg is formed.

[0080] The quartz glass is sampled after external processing, and the bubble density is measured to be 0.5 / 100kg, and the carbon content is about 80ppb; after vacuum annealing at 1200℃ for 200h, the refractive index is tested, and the optical inhomogeneity Δn in the aperture is 2.5x10 -6 .

[0081] Example 3

[0082] The method for preparing high-uniformity quartz glass in this example is implemented by using the system for preparing high-uniformity quartz glass in Example 1, and specifically includes the following steps:​

[0083] S1, octamethylcyclotetrasiloxane (D4) with a purity of 99.5% is subjected to two batch rectifications by a double-tower rectification device to obtain liquid octamethylcyclotetrasiloxane with a purity of 99.99%.

[0084] S2, nitrogen is preheated to 200°C by a first heating device, and octamethylcyclotetrasiloxane with a mass flow of 30 g / min is blown into a second heating device for gasification at 200°C to obtain a mixed gas with a volume ratio of octamethylcyclotetrasiloxane to carrier gas of 1:8;

[0085] S3, oxygen is preheated to 200°C by a third heating device, and is introduced into a Venturi tube together with the mixed gas for primary mixing, and then is introduced into a static spiral mixer for secondary mixing for 5 s, and finally is filtered through a metal nickel filter membrane with a pore size of 5 nm to obtain a premixed reaction gas with a mass ratio of octamethylcyclotetrasiloxane to oxygen of 5:1;

[0086] S4, the premixed reaction gas is split in a volume ratio of 2:1, is uniformly distributed through a gas pipeline, and is introduced into the central tube and the interlayer tube cavity of the burner at a flow rate of 15 g / min and 15 g / min, respectively; at the same time, nitrogen gas with a total flow rate of 40 L / min (1:1) is introduced into the first and second isolation nitrogen cavities through the gas pipeline; hydrogen gas with a total flow rate of 550 L / min (1:1) is introduced into the inner and outer hydrogen cavities; oxygen gas with a total flow rate of 270 L / min (1:1) is introduced into the first, second, and third oxygen core through pipes; oxygen gas with flow rates of 40 L / min, 25 L / min, and 15 L / min is introduced into the first, second, and third peripheral oxygen cavities, respectively, and is deposited on a quartz support platform at a deposition rate of 2 mm / h, a flame temperature of 1700°C, and a reaction cavity under a slightly positive pressure. During the deposition process, the quartz support platform rotates and moves radially reciprocally through a planetary rotation mechanism at a rotation speed of 12 r / min, a radial reciprocating stroke of ±36 mm, and a frequency of 0.01 Hz. After 15 days of deposition, a quartz glass with a diameter of 600 mm, a height of 430 mm, and a single weight of about 265 kg is formed.

[0087] The quartz glass is sampled after external processing, and the bubble density is measured to be 0.8 per 100 kg, and the carbon content is about 75 ppb; after vacuum annealing at 1200°C for 200 h, the refractive index is tested, and the optical inhomogeneity Δn in the aperture is 3.8×10 -6 .

[0088] Comparative Example 1

[0089] ​The same as example 2, except that the burner is replaced by the burner in CN115353277A A kind of deposition kiln for synthesizing quartz and preparation method;After depositing for 15 days, quartz glass with a diameter of 600mm, a height of 400mm and a single weight of about 235kg is formed.

[0090] The quartz glass is sampled by external processing, and the bubble density is 1.8 / 100kg, and the carbon content is about 500ppm;After vacuum annealing at 1200℃ for 200h, the refractive index is tested, and the test The in-bore optical non-uniformity Δn is 25×10 -6 .

[0091] Comparative example 2

[0092] The same as example 2, except that multi-stage mixing is not performed, and the mixed gas and oxygen are mixed and then sent into the burner;After depositing for 10 days, quartz glass with a diameter of 600mm, a height of 290mm and a single weight of about 180kg is formed.

[0093] The quartz glass is sampled by external processing, and the bubble density is 10 / 100kg, and the carbon content is about 130ppm;After vacuum annealing at 1200℃ for 200h, the refractive index is tested, and the test The in-bore optical non-uniformity Δn is 6×10 -6 .

[0094] Obviously, the above examples are only examples for the sake of clarity, and are not limitations on the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. It is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A system for producing high homogeneity quartz glass, characterized by, It comprises: A multi-stage dynamic mixer, comprising a heating device, a Venturi tube, a static spiral mixer and a metal filter membrane connected in sequence, wherein the heating device comprises a first heating device, a second heating device and a third heating device; the output end of the first heating device is connected with the input end of the second heating device; the output ends of the second heating device and the third heating device are respectively connected with the input end of the Venturi tube; A burner, comprising a center tube, a nitrogen isolation cavity, an oxygen core tube, an inner hydrogen cavity, a sandwich tube cavity, a second nitrogen isolation cavity, a second oxygen core tube, a third oxygen core tube, an outer hydrogen cavity, a first peripheral oxygen cavity, a second peripheral oxygen cavity and a third peripheral oxygen cavity arranged coaxially from inside to outside; A plurality of center tubes are arranged in the form of a ring in the nitrogen isolation cavity; a plurality of oxygen core tubes are arranged in the form of a ring between the nitrogen isolation cavity and the inner hydrogen cavity; a plurality of second oxygen core tubes and a plurality of third oxygen core tubes are arranged in the form of a ring between the second nitrogen isolation cavity and the outer hydrogen cavity; and the second oxygen core tube is close to the second nitrogen isolation cavity; and the third oxygen core tube is close to the outer hydrogen cavity; The output end of the metal filter membrane is connected with the input end of the burner.

2. The system for producing high homogeneity quartz glass according to claim 1, characterized in that, The center tube is arranged in a center tube shell; The nitrogen isolation cavity is arranged in a nitrogen isolation cavity shell; The oxygen core tube is arranged in an oxygen core tube shell; The inner hydrogen cavity is arranged in an inner hydrogen cavity shell; The sandwich tube cavity is arranged in a sandwich tube cavity shell; The second nitrogen isolation cavity is arranged in a second nitrogen isolation cavity shell; The second oxygen core tube is arranged in a second oxygen core tube shell; The third oxygen core tube is arranged in a third oxygen core tube shell; The outer hydrogen cavity is arranged in an outer hydrogen cavity shell; The first peripheral oxygen cavity is arranged in a first peripheral oxygen cavity shell; The second peripheral oxygen cavity is arranged in a second peripheral oxygen cavity shell; The third peripheral oxygen cavity is arranged in a third peripheral oxygen cavity shell.

3. A method of making high homogeneity quartz glass, characterized in that, The system for preparing high-uniformity quartz glass according to claim 1 or 2 is implemented, comprising the following steps: S1, preheating the carrier gas by the first heating device, and blowing octamethylcyclotetrasiloxane into the second heating device for gasification to obtain a mixed gas; S2, preheating the oxygen by the third heating device, and passing the mixed gas obtained in S1 and the preheated oxygen into the Venturi tube for primary mixing, then into the static spiral mixer for secondary mixing, and finally filtering through the metal filter membrane to obtain a premixed reaction gas; S3, passing the premixed reaction gas obtained in S2 into the center tube and the sandwich tube cavity of the burner at a first preset flow rate and a second preset flow rate respectively; at the same time, passing nitrogen at a third preset flow rate into the first nitrogen isolation cavity and the second nitrogen isolation cavity; passing hydrogen at a fourth preset flow rate into the inner hydrogen cavity and the outer hydrogen cavity; passing oxygen at a fifth preset flow rate into the first oxygen core tube, the second oxygen core tube and the third oxygen core tube; and passing oxygen into the first peripheral oxygen cavity, the second peripheral oxygen cavity and the third peripheral oxygen cavity, and the oxygen flow rate decreases along the radial direction of the burner, and the quartz glass is deposited on the quartz supporting platform to obtain high-uniformity quartz glass.

4. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S1, the carrier gas is selected from nitrogen, argon or helium; ​ The preheating temperature is 150-250℃; The gasification temperature is 150-250℃; The volume ratio of octamethylcyclotetrasiloxane to carrier gas is 1:(4-8).

5. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S2, the preheating temperature is 150-250℃; ​ The mass ratio of octamethylcyclotetrasiloxane to oxygen in the mixed gas is (5-10):

1.

6. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S2, the secondary mixing time is at least 0.5s; ​ The pore size of the metal filter membrane is 5-100nm.

7. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S3, the first and second preset flow rates are independently 10-50g / min, and the ratio of the first to second preset flow rates is (1-2):1; ​ The third preset flow rate is 10-50L / min; The fourth preset flow rate is 300-700L / min; The fifth preset flow rate is 100-300L / min.

8. The method for preparing highly uniform quartz glass according to claim 3, characterized in that, In S3, the oxygen flow rates of the one-layer, two-layer and three-layer peripheral oxygen cavities are 30-40L / min, 20-25L / min and 10-15L / min, respectively.

9. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S3, the deposition rate is 1-3mm / h, and the flame temperature is 1400-2000℃. ​ 10. The method of claim 3, wherein the high homogeneity quartz glass is prepared by the steps of: In S3, during the deposition process, the rotation speed of the quartz support platform is 5-20r / min, the stroke of the radial reciprocating movement is 20-50mm, and the frequency is 0.005-0.05Hz. ​

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