Synthetic quartz glass preparation device for excimer laser

Abstract

The utility model belongs to the field of quartz synthesis, and particularly relates to a synthetic quartz glass preparation device for an excimer laser. Comprising a loose body deposition system and a loose body sintering system; the loose body deposition system is sequentially provided with a quartz outer cavity, a quartz inner cavity with an opening in the top and a rotary quartz guide rod from outside to inside; the loose body sintering system is sequentially provided with a vacuum sintering furnace shell, a medium-frequency heating device, a quartz tube and a loose body from outside to inside; the synthesized optical element does not contain chlorine, oxygen deficiency sites and SiH groups, has extremely high ultraviolet transmittance and low absorptivity, is used for an optical system of ArF exposure equipment for transmitting ArF excimer laser, and has the refractive index uniformity [delta] n of 1 * 10 <-6 > or less, the stress birefringence amount of 1 nm / cm or less, the internal transmittance of 99.7% or more for ultraviolet rays with the wavelength of 193.4 nm, the OH group concentration of 1 ppm or less, and the refractive index uniformity [delta] n of 1 * 10 <-6 > or less. And the content of metal impurities is less than 10ppb.

Description

Technical Field

[0001] This utility model belongs to the field of quartz synthesis, specifically relating to a device for preparing synthetic quartz glass for excimer lasers. Background Technology

[0002] Synthetic quartz glass is composed of Si and O in a molar ratio of 1:2, and its basic structural unit is the [SiO4] tetrahedron. Quartz glass is an amorphous material, meaning that the unit cells in its structure are disordered, unlike the ordered arrangement of [SiO4] to form quartz crystals. This material is widely used in high-tech industries such as microelectronics, precision optics, space technology, and laser technology due to its high transmittance, high thermal stability, and chemical stability. Among these, synthetic quartz materials with high ultraviolet transmittance are widely used in lenses and other optical components of precision optical devices. However, its transmittance in the ultraviolet band is deficient, resulting in significant energy loss when light beams pass through silica. Simultaneously, absorption is converted into heat, affecting its lifespan. This insufficient transmittance greatly limits the further applications of synthetic quartz.

[0003] Quartz glass theoretically possesses high transmittance in the 157 and 4000 nm range. However, due to Urbach absorption edges and Rayleigh scattering, the transmittance of quartz glass typically falls far short of the theoretical limit. Impurities such as elements and functional groups, along with structural defects, cause significant absorption in the ultraviolet band, resulting in poor transmittance in the ultraviolet region. For highly pure synthetic quartz glass, the latter is the primary cause. Regarding structural defects, point defects can be viewed as point defects within the [SiO4] tetrahedral unit, related to whether atoms are bonded to each other and to which atoms. Another type is slightly larger, related to the connections between structural units. A silicon dangling bond (E' center, Si·) consists of an ionized single oxygen vacancy and an unpaired electron. A peroxy radical is a non-bridging superoxide ion (O2-) bonded to a single silicon atom in the glass network, (POR, SiOO·) a non-bridging oxygen hole center Si-O·, referring to a bond with three oxygen atoms, where (·) represents an unpaired electron. Point defects lead to absorption in the ultraviolet (UV) region. Oxygen-deficient centers (ODCs) and E' centers are caused by the absence of oxygen atoms. The former leads to absorption near 243 nm, while the latter has a characteristic absorption peak at 215 nm. In the absence of hydrogen, peroxy radicals (PORs), peroxy bonds, and non-bridging oxygen hole centers (NBOHCs) are generated. The absorption peaks of peroxy bonds and NBOHCs are at 330 nm and 265 nm, respectively. Hydrogen doping and fluorine doping are commonly used to suppress NBOHCs generated under laser irradiation. Hosono et al. found that strain ring structures in materials can cause a redshift in the UV absorption limit. At sites with angles far from the average value, angled Si-O-Si with moderately reduced bonding energy can influence VU absorption of silicon dioxide by generating near-edge localized electronic states or acting as precursors for color centers. Koichi proposed a method to improve the vacuum UV transmittance of materials by modifying point defects and showed that fluorine doping can effectively prevent the formation of Si-Cl and Si-OH, thereby improving the transmittance in the VUV region.

[0004] The optical system of a lithography machine is one of its most critical and complex parts, comprising two core components: the illumination system and the projection lens. The projection lens is crucial for achieving precise imaging in a lithography machine; its main function is to image the mask pattern onto the silicon wafer at a specific scaling ratio. The construction of a projection lens is extremely complex, typically consisting of multiple lenses. For example, ASML's DUV lithography machine lens consists of 29 lenses, designed to minimize aberrations. Among these, refractive projection lenses are mostly made of fused silica. It is understood that only Heraeus in Germany and Corning in the United States can provide fused silica that meets the requirements for 193nm lithography.

[0005] Since the minimum feature size of an imaging structure decreases as the wavelength gets shorter, modern semiconductor chips are manufactured using ArF excimer lasers with a wavelength of 193 nanometers (deep ultraviolet: DUV) as the light source.

[0006] The optical material chosen for microlithography optics is synthetic fused silica (CFD) because it fully supports the aforementioned requirements for an aberration-free DUV optical system. CFD requires extremely high ultraviolet transmittance and low absorptivity. The CFD glass material used in the optical system of ArF exposure equipment transmitting ArF excimer lasers has extremely low structural defects, a refractive index uniformity Δn below 1 × 10⁻⁶, birefringence below 1 nm / cm, an internal transmittance of over 99.7% for ultraviolet light at a wavelength of 193.4 nm, an OH group concentration below 1 ppm, and a metallic impurity content below 10 ppb. Only optimized CFD types can maintain their excellent initial performance over an expected service life of approximately 10 years.

[0007] Currently, there are three methods for producing synthetic quartz:

[0008] 1. Chemical Vapor Deposition (CVD) process

[0009] Chemical vapor deposition (CVD) refers to the deposition of silicon-containing compounds (such as inorganic and organic raw materials like SiCl4, SiH4, and Si4O4(CH3)8) in the atmosphere of H2O. 2 High-temperature hydrolysis or oxidation in a flame generates SiO2 particles, which are then deposited layer by layer onto a rotating substrate to form transparent quartz glass.

[0010] Synthetic quartz glass prepared by chemical vapor deposition has the characteristics of low metal impurity content (<2ppm), high far-ultraviolet transmittance (T185-2000nm≥85%), and high optical uniformity (better than 2×10⁻⁶). -6 It has excellent radiation resistance (withstanding space radiation for more than 15 years); however, its hydroxyl content is as high as 1200ppm, and there is a large absorption peak at 2.73μm, which affects its infrared optical performance.

[0011] 2. Plasma Chemical Vapor Deposition (PCVD) process

[0012] Plasma chemical vapor deposition (PCVD) is a process that uses high-purity SiCl4 as raw material and high-frequency plasma flames instead of oxyhydrogen flames to synthesize quartz glass in the gas phase. Quartz glass prepared by PCVD has low levels of metallic impurities and hydroxyl groups, giving it excellent ultraviolet-infrared spectral transmittance, stable refractive index, and high structural uniformity. In 1966, Corning Incorporated in the United States invented a new process for producing high-purity, hydroxyl-free quartz glass using high-frequency plasma. This process achieves metallic impurities of less than 5 ppm, hydroxyl content of 0-10 ppm, and chlorine content of 50-90 ppm, meeting the requirements for quartz glass used in solar simulators, infrared tracking systems, and spectrometers with wavelengths of 0.18-5 μm.

[0013] 3. Indirect synthesis methods (VAD and OVD)

[0014] The indirect synthesis method, in contrast to the four common "direct methods" of quartz glass production—electrofusion, gas refining, CVD, and PCVD (which directly produce quartz glass from raw materials in a single step at temperatures above 1800℃)—involves two main steps: the deposition and sintering of a low-density SiO2 porous body. Using silicon-containing compounds (such as SiCl4) as raw materials, a low-temperature chemical vapor deposition process is employed to first deposit a low-density SiO2 porous body, which is then sintered. During sintering, doping, dehydration, degassing, and densification occur simultaneously until vitrification is achieved. Because this method uses oxyhydrogen flame hydrolysis, the porous body contains a large amount of water. Direct sintering would result in a large number of hydroxyl groups (100-300 ppm), necessitating sintering in a halogen-containing atmosphere to reduce the hydroxyl content to 1-10 ppm. However, residual chloride ions may remain in the finished product, affecting its uniformity. Utility Model Content

[0015] To address the aforementioned technical problems, this application provides the following technical solution:

[0016] This invention provides a synthetic quartz glass preparation apparatus for excimer lasers, including a bulk deposition system and a bulk sintering system;

[0017] The porous body deposition system consists of a quartz outer cavity, a quartz inner cavity with an open top, and a rotating quartz guide rod, arranged sequentially from the outside to the inside.

[0018] The rotating quartz guide rod is vertically positioned and can move up and down in the vertical direction, with a support plate at the top; the top of the quartz outer cavity is equipped with several blowtorches, which extend vertically downward through the top of the quartz outer cavity, with the distance between the bottom of the blowtorch and the support plate being 35-100mm; the bottom of the quartz outer cavity is equipped with a vacuum device; the bottom of the quartz inner cavity is equipped with several air inlets, and the sides of the quartz outer cavity are equipped with several air outlets;

[0019] The porous body sintering system consists of a vacuum sintering furnace shell, a medium-frequency heating device, a quartz tube, and porous body, arranged sequentially from the outside to the inside.

[0020] The vacuum sintering furnace shell includes a water cooling system, a cooling water inlet and an outlet; the side of the vacuum sintering furnace shell is also provided with a vacuum exhaust port; one end of the vacuum exhaust port is connected to a vacuum pump; the medium frequency heating device includes a tungsten metal tube and a medium frequency coil arranged sequentially outside the quartz tube.

[0021] Preferably, in the loose body deposition system, the air inlet and the air outlet are symmetrically arranged.

[0022] Preferably, in the porous body deposition system, a pressure gauge is also provided at the top of the quartz outer cavity.

[0023] Preferably, the porous body deposition system further includes a pixel camera recognition device for controlling the stability of the tray position.

[0024] Preferably, the side of the quartz tube is provided with a nanoscale filter.

[0025] Preferably, the bottom of the quartz tube is provided with a lower sealing plate.

[0026] This utility model also provides a method for producing synthetic quartz glass for excimer lasers, using the above-mentioned apparatus for preparing synthetic quartz glass for excimer lasers, including the following steps:

[0027] S11: In the porous body deposition system, under a protective atmosphere, vaporized octamethylcyclotetrasiloxane and oxygen are introduced through a blowtorch to begin depositing silica porous body on a tray; the tray is rotated by a rotating quartz rod, and the blowtorch and tray are heated to 1000-1200℃ during deposition; the heating method of the blowtorch is microwave plasma heating;

[0028] S12: Pull the rotating quartz rod and support plate downwards in the vertical direction to cause the deposited silica porous body to descend and grow, thereby obtaining the deposited product;

[0029] S13: Transfer the silica porous body to the quartz tube of the porous body sintering system, and sinter at 1400-1600℃ for 1×10⁻⁶ hours. -1 After sintering at ~1 Pa for 2-4 h, the temperature was lowered to room temperature (25±5℃) to obtain synthetic quartz glass for excimer lasers.

[0030] Preferably, in step S11, the heating pressure is 5-45 Pa and the rotation speed is 30-80 rpm; in step S13, the sintering is performed by rotation at a speed of 1-10 rpm; the sintering uses a medium-frequency heating device with a working frequency of 50-2000 Hz.

[0031] Preferably, the synthetic quartz glass used in the excimer laser has an outer diameter of 300-600 mm and a density of 0.5-1.2 g / cm³. 3 The length is 1000-2000mm.

[0032] Preferably, in step S13, water is used to cool the furnace body of the porous body sintering system during sintering, and the surface temperature of the furnace body is controlled below 30°C.

[0033] Preferably, in step S13, water and oxygen are replaced 2-5 times before sintering. The replacement steps are as follows:

[0034] S21: Evacuate the porous sintering system to 0.01-0.1 Pa at 100-300℃;

[0035] S22: Charge the porous body sintering system with helium to atmospheric pressure (100-102 kPa) and let it stand for 15 minutes.

[0036] Optical components produced by this method have a chlorine content of less than 10 wt.ppm, a hydroxyl content of less than 1 wt.ppm, a carbon content of less than 1 wt.ppm, a metallic impurity content of less than 10 wt.ppb, a glass structure with virtually no oxygen defects, no striations in any of the three dimensions, and an optical non-uniformity of less than 1 × 10⁻⁶. -6 The stress is less than 1 nm / cm.

[0037] The technical solution of this utility model has the following advantages compared with the prior art:

[0038] The synthetic quartz glass material used in the ArF exposure equipment of this invention has a refractive index uniformity Δn of 1×10⁻⁶. -6 The following are characteristics of synthetic quartz glass materials used in the optical systems of ArF exposure equipment for transmitting ArF excimer lasers: stress birefringence below 1 nm / cm, hydroxyl, chlorine, and carbon content less than 1 wt.ppm, and metallic impurity content less than 10 wt.ppb. These materials have an energy density per pulse ranging from 0.001 to 0.5 mJ / cm². 2 The internal transmittance of ultraviolet light with a wavelength of 193.4 nm is over 99.7%. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of loose body deposition;

[0040] Figure 2 Schematic diagram of porous body sintering;

[0041] Explanation of reference numerals in the attached drawings: 101-Blowtorch, 102-Pressure gauge, 103-Support plate, 104-Exhaust vent, 105-Quartz inner cavity, 106-Quartz outer cavity, 107-Air inlet, 108-Rotating quartz guide rod, 201-Vacuum sintering furnace shell, 202-Cooling water inlet, 203-Quartz tube, 204-Vacuum exhaust port, 205-Tungsten metal tube, 206-Medium frequency coil, 207-Porous body, 208-Nanoscale filter, 209-Lower sealing plate, 210-Water outlet. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0043] Example 1

[0044] An apparatus for preparing synthetic quartz glass for excimer lasers includes a bulk deposition system and a bulk sintering system;

[0045] The porous body deposition system consists of a quartz outer cavity 106, a quartz inner cavity 105 with a top opening, and a rotating quartz guide rod 108, arranged sequentially from the outside to the inside.

[0046] The rotating quartz guide rod 108 is vertically positioned and can move up and down vertically, with a support plate 103 at its top. The top of the quartz outer cavity 106 is equipped with several blowtorches 101, which extend vertically downwards through the top of the quartz outer cavity 106, with the bottom of the blowtorch 101 and the support plate 103 being 35-100 mm apart. A vacuum device is located at the bottom of the quartz outer cavity 106. The bottom of the quartz inner cavity 105 has several air inlets 107, and the sides of the quartz outer cavity 106 have several exhaust ports 104. In this porous deposition system, the air inlets 107 and exhaust ports 104 are symmetrically arranged. A pressure gauge 102 is also located at the top of the quartz outer cavity 106. The porous deposition system also includes a pixel camera recognition device for stabilizing the position of the support plate 103.

[0047] The porous body sintering system consists of, from the outside in, a vacuum sintering furnace shell 201, a medium-frequency heating device, a quartz tube 203, and a porous body 207;

[0048] The vacuum sintering furnace shell 201 includes a water cooling system, a cooling water inlet 202, and a water outlet 210. A vacuum exhaust port 204 is also provided on the side of the vacuum sintering furnace shell 201. One end of the vacuum exhaust port 204 is connected to a vacuum pump. The medium-frequency heating device includes a tungsten metal tube 205 and a medium-frequency coil 206 sequentially disposed outside a quartz tube 203. A nano-scale filter 208 is provided on the side of the quartz tube 203, and a lower sealing plate 209 is provided at the bottom.

[0049] Example 2

[0050] The preparation system provided in this embodiment consists of a porous body deposition system and a porous body sintering system;

[0051] The loose mass deposition system consists of: a raw material supply system, a reaction system, a lifting system, a control system, and an exhaust system.

[0052] Raw material supply system: It uses octamethylcyclotetrasiloxane as raw material and completes the gasification of raw material through an atomization device.

[0053] Reaction system: Using microwave plasma and oxygen as heat sources, an oxidation reaction occurs with octamethylcyclotetrasiloxane to produce SiO2 aerosol.

[0054] Lifting system: controls the position of the deposition surface. The position of the blowtorch 101 is fixed. As the loose material is deposited, the lifting system controls the loose material on the tray 103 to descend.

[0055] Control system: The position of the deposition surface is identified by a pixel camera, and the position of the deposition surface is kept constant by controlling the speed of the motor.

[0056] Exhaust system: The exhaust system discharges the undeposited SiO2 powder, and at the same time, the exhaust volume is controlled by a pressure sensor to maintain a slight positive pressure inside the cavity.

[0057] The porous body sintering system consists of a water cooling system, a vacuum system, a medium-frequency heating system, a workpiece melting system, and a filtration system.

[0058] Water cooling system: Deionized water is used to cool the furnace body, and the surface temperature of the furnace body is controlled below 30℃.

[0059] Vacuum system: A vacuum pump is used to create a negative pressure inside the furnace cavity, with a pressure range of 1 to 10. -4 pa.

[0060] Medium frequency heating system: The working frequency of the medium frequency induction furnace is between 50-2000Hz, and the temperature range is 1200-1800℃.

[0061] Workpiece melting system: The workpiece is melted inside a sealed quartz tube, and the sintering temperature is 1200-1800℃.

[0062] Filtration system: A nano-level filter 208 is used to allow gas inside the quartz tube to escape while preventing external impurities from entering the quartz tube.

[0063] Example 3

[0064] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0065] 1. Deposition preparation: The motor drives the spindle to rotate at 50 rpm, and the quartz substrate is heated to 1200℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 5 Pa.

[0066] 2. Material deposition: The blowtorch 101, heated to 1200℃, is used to pass octamethylcyclotetrasiloxane and oxygen to deposit SiO2 porous material on the quartz substrate (i.e., tray 103); the distance between the blowtorch 101 and the quartz substrate is 35mm.

[0067] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0068] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0069] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a rotation speed of 5 rpm;

[0070] 6. Low-temperature vacuuming: At 200℃, a vacuum is drawn, and the negative pressure in the cavity is 0.05Pa.

[0071] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0072] 8. Repeat steps 6 and 7 twice;

[0073] 9. High-temperature vacuuming, using a medium-frequency induction furnace with a working frequency of 1000Hz, a temperature of 1500℃, a cavity negative pressure of 1Pa, and constant temperature and pressure for 3 hours.

[0074] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0075] Example 4

[0076] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0077] 1. Deposition preparation: The motor drives the spindle to rotate at 50 rpm, and the quartz substrate is heated to 1200℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 15 Pa.

[0078] 2. Material deposition: Octamethylcyclotetrasiloxane and oxygen are introduced into the blowtorch 101 heated to 1200℃ to deposit SiO2 loose material on the quartz substrate (i.e., tray 103); the distance between the blowtorch 101 and the quartz substrate is 50mm.

[0079] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0080] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0081] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a rotation speed of 5 rpm;

[0082] 6. Low-temperature vacuuming: At 200℃, a vacuum is drawn, and the negative pressure in the cavity is 0.05Pa.

[0083] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0084] 8. Repeat steps 6 and 7 twice;

[0085] 9. High temperature vacuuming, using a medium frequency induction furnace with a working frequency of 1000Hz, a temperature of 1500℃, a cavity negative pressure of 0Pa, and constant temperature and pressure for 3 hours.

[0086] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0087] Example 5

[0088] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0089] 1. Deposition preparation: The motor drives the spindle to rotate at 50 rpm, and the quartz substrate is heated to 1200℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 25 Pa.

[0090] 2. Material deposition: A blowtorch 101 heated to 1200℃ is used to pass octamethylcyclotetrasiloxane and oxygen to deposit SiO2 loose material on a quartz substrate (i.e., tray 103); the distance between the blowtorch 101 and the quartz substrate is 65mm.

[0091] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0092] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0093] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a rotation speed of 5 rpm;

[0094] 6. Low-temperature vacuuming: At 200℃, a vacuum is drawn, and the negative pressure in the cavity is 0.05Pa.

[0095] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0096] 8. Repeat steps 6 and 7 twice;

[0097] 9. High-temperature vacuuming: The working frequency of the medium-frequency induction furnace is 1000Hz, the temperature is 1500℃, the negative pressure in the cavity is 0.5Pa, and the temperature and pressure are kept constant for 3 hours.

[0098] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0099] Example 6

[0100] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0101] 1. Deposition preparation: The motor drives the spindle to rotate at 50 rpm, and the quartz substrate is heated to 1200℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 35 Pa.

[0102] 2. Material deposition: Octamethylcyclotetrasiloxane and oxygen are introduced into the blowtorch 101 heated to 1200℃ to deposit SiO2 loose material on the quartz substrate (i.e., tray 103); the distance between the blowtorch 101 and the quartz substrate is 80mm.

[0103] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0104] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0105] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a rotation speed of 5 rpm;

[0106] 6. Low-temperature vacuuming: At 200℃, a vacuum is drawn, and the negative pressure in the cavity is 0.05Pa.

[0107] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0108] 8. Repeat steps 6 and 7 twice;

[0109] 9. High-temperature vacuuming, using a medium-frequency induction furnace with a working frequency of 1000Hz, a temperature of 1500℃, a cavity negative pressure of 0.1Pa, and constant temperature and pressure for 3 hours.

[0110] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0111] Table 1. Performance characterization of synthetic quartz glass used in excimer lasers in Examples 3 to 6.

[0112]

[0113] Example 7

[0114] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0115] 1. Deposition preparation: The motor drives the spindle to rotate at 30 rpm, and the quartz substrate is heated to 1000℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 5 Pa.

[0116] 2. Material deposition: Octamethylcyclotetrasiloxane and oxygen are introduced into the blowtorch 101 heated to 1000℃ to deposit SiO2 porous body on the quartz substrate (i.e., tray 103).

[0117] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0118] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0119] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a speed of 1 rpm.

[0120] 6. Low-temperature vacuuming: At 100℃, a vacuum is drawn, creating a negative pressure of 10 in the cavity. -1 pa;

[0121] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0122] 8. Repeat steps 6 and 7 twice;

[0123] 9. High temperature vacuuming, using a medium frequency induction furnace with a working frequency of 50Hz, a temperature of 1400℃, a cavity negative pressure of 1pa, and constant temperature and pressure for 2 hours.

[0124] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0125] Example 8

[0126] A method for producing synthetic quartz glass for excimer lasers, using the preparation system of Example 1, with the following process steps:

[0127] 1. Deposition preparation: The motor drives the spindle to rotate at 80 rpm, and the quartz substrate is heated to 1200℃ through the plasma heat source; at the same time, dry protective gas is introduced through the air inlet 107 to keep the cavity under slight positive pressure at 45 Pa.

[0128] 2. Material deposition: Octamethylcyclotetrasiloxane and oxygen are introduced into the blowtorch 101 heated to 1200℃ to deposit SiO2 porous body on the quartz substrate (i.e., tray 103).

[0129] 3. Deposition control: The loose material is lowered by a lifting device; the deposition surface is kept constant by a pixel camera.

[0130] 4. Product transfer: After reaching the set length, the loose body is removed and prepared for sintering. The transfer device is protected by gas, and the water content of the protective gas is less than 1 wt.ppm.

[0131] 5. Product sintering and installation: Install the product into the quartz tube 203 of the porous body sintering system at a speed of 10 rpm.

[0132] 6. Low-temperature vacuuming: At 300℃, a vacuum is drawn, creating a negative pressure of 10 in the cavity. -2 pa;

[0133] 7. Gas replacement: Slowly fill the vacuum furnace with dry He until it reaches atmospheric pressure and stands for 15 minutes;

[0134] 8. Repeat steps 6 and 7 five times;

[0135] 9. High-temperature vacuuming: The medium-frequency induction furnace operates at a frequency of 2000Hz, a temperature of 1600℃, and a cavity negative pressure of 10. -1 Pa, constant temperature and pressure for 4 hours;

[0136] 10. Take out the material, cool it to room temperature, remove the material, and the operation is complete.

[0137] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. An apparatus for preparing synthetic quartz glass for excimer lasers, characterized in that, Including porous body deposition systems and porous body sintering systems; The porous body deposition system consists of a quartz outer cavity (106), a quartz inner cavity (105) with an open top, and a rotating quartz guide rod (108) arranged sequentially from the outside to the inside. The rotating quartz guide rod (108) is vertically arranged and can move up and down in the vertical direction. It is equipped with a support plate (103) at the top. The top of the quartz outer cavity (106) is equipped with several blowtorches (101). The blowtorches (101) extend downward through the top of the quartz outer cavity (106) in the vertical direction. The distance between the bottom of the blowtorch (101) and the support plate (103) is 35-100mm. The bottom of the quartz outer cavity (106) is equipped with a vacuum device. The bottom of the quartz inner cavity (105) is equipped with several air inlets (107). The two sides of the quartz outer cavity (106) are equipped with several exhaust vents (104). The porous body sintering system consists of a vacuum sintering furnace shell (201), a medium-frequency heating device, a quartz tube (203), and a porous body (207) arranged sequentially from the outside to the inside. The vacuum sintering furnace shell (201) includes a water cooling system, a cooling water inlet (202) and an outlet (210); the side of the vacuum sintering furnace shell (201) is also provided with a vacuum exhaust port (204); one end of the vacuum exhaust port (204) is connected to a vacuum pump; the medium frequency heating device includes a tungsten metal tube (205) and a medium frequency coil (206) arranged sequentially outside the quartz tube (203).

2. The apparatus for preparing synthetic quartz glass for excimer lasers as described in claim 1, characterized in that, In the loose body deposition system, the air inlet (107) and the air outlet (104) are symmetrically arranged.

3. The apparatus for preparing synthetic quartz glass for excimer lasers as described in claim 1, characterized in that, In the porous body deposition system, a pressure gauge (102) is also provided on the top of the quartz outer cavity (106).

4. The apparatus for preparing synthetic quartz glass for excimer lasers as described in claim 1, characterized in that, The loose body deposition system also includes a pixel camera recognition device for controlling the position stability of the tray (103).

5. The apparatus for preparing synthetic quartz glass for excimer lasers as described in claim 1, characterized in that, The quartz tube (203) is provided with a nano-scale filter (208) on its side.

6. The apparatus for preparing synthetic quartz glass for excimer lasers as described in claim 1, characterized in that, The bottom of the quartz tube (203) is provided with a lower sealing plate (209).

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