A combined surface treatment method for fused quartz components to improve laser damage resistance

Abstract

The present invention discloses a surface combined treatment method for fused silica components to improve the anti-laser damage ability, which includes: ultrasonically cleaning the fused silica components in ethanol to remove dust and oil stains on the surface, and then ultrasonically cleaning the fused silica components in deionized water; placing the cleaned fused silica components in a parallel plate discharge etcher for reactive ion etching, cleaning the surface of the components with inorganic acid after etching, and then cleaning with deionized water and drying; placing the cleaned fused silica components in a high-temperature annealing furnace for high-temperature annealing treatment; placing the fused silica components after high-temperature annealing treatment in an H2O2 etcher for secondary etching; cleaning the etched fused silica components with deionized water and ethanol. The present invention effectively improves the laser damage threshold of the surface of the fused silica components by better repairing the defects on the surface of the fused silica components and improving the surface quality through a combined etching method.

Description

Technical Field

[0001] The present invention belongs to the technical field of post-processing of optical materials, and more specifically, relates to a combined surface processing method for fused quartz components for improving the ability to resist laser damage. Background Art

[0002] Due to its excellent performance, fused silica glass has always been used as a key component of many important optical components in high-energy laser systems. However, the degradation of optical properties caused by laser-induced damage has posed a huge obstacle to the development of high-energy density scientific fields such as inertial confinement fusion and high-energy lasers.

[0003] The laser-induced damage threshold of fused silica measured so far is often less than one-tenth of its intrinsic threshold. The fundamental reason is that surface defects are introduced into the components during the early cold processing processes such as grinding and polishing. Generally, destructive defects such as scratches or pits introduced in the sub-surface by various surface processing processes will lead to a higher probability of laser-induced damage. At the same time, contamination defects in the form of impurity elements (such as Ce, Fe, etc.) introduced through the polishing process or environmental pollution can lead to enhanced laser absorption, thereby reducing the laser damage threshold. In addition, chemical structural defects such as non-bridging oxygen centers (NBOHC) and oxygen vacancy centers (ODC) are also related to the generation of laser damage in fused silica glass. These defects are extremely easy to be damaged under laser pulse irradiation, and the damage scale increases rapidly with the increase in the number of irradiation times. Sub-surface defects can cause the optical function of the component to degrade or even fail, severely limiting the load capacity of the laser drive system and greatly increasing the system operation and maintenance burden.

[0004] In order to eliminate these surface defects, people have developed various surface treatment processes and methods. For example, reactive ion etching (RIE) is an etching process that combines physical bombardment and chemical etching. It generates active groups through fluorine-containing gas discharge, interacts with the surface of fused quartz materials, and anisotropically removes surface and subsurface defects of the material. For example, it can remove the polishing re-deposition layer rich in photosensitive impurity elements such as Ce and Zr, as well as the subsurface damage layer composed of broken cracks, scratches, etc., thereby greatly improving the damage resistance of the component. However, with the increase of etching depth, the increase of chemical structural defects (ODC and NBOHC, etc.) and material densification, as well as the contaminating impurities such as F elements introduced near the surface during etching will become an important reason for further limiting the improvement of the laser damage resistance of fused quartz components.

[0005] Therefore, single reactive ion etching can no longer meet the actual engineering needs, and there is an urgent need to explore a surface post-treatment method that can effectively improve the ability of fused quartz components to resist laser damage to solve the above technical problems. Summary of the invention

[0006] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0007] In order to achieve these purposes and other advantages according to the present invention, a combined surface treatment method for a fused quartz component for improving the ability to resist laser damage is provided, comprising the following steps:

[0008] Step 1: ultrasonically clean the fused quartz element in ethanol to remove dust and oil stains on the surface, and then ultrasonically clean the fused quartz element in deionized water to further remove impurities on the surface of the fused quartz element;

[0009] Step 2: placing the fused quartz element cleaned in step 1 in a parallel plate discharge etcher for reactive ion etching, cleaning the surface of the element with inorganic acid after etching to dissolve the metal impurities that may remain in the reactive ion etching process, and then cleaning with deionized water and drying;

[0010] Step 3: placing the fused quartz element cleaned in step 2 in a high temperature annealing furnace for high temperature annealing to converge the sub-surface physical structure defects remaining after the reactive ion etching treatment, eliminate the residual stress and densification, and at the same time migrate the impurity elements in the sub-surface layer to the near surface;

[0011] Step 4: placing the fused quartz element after the high temperature annealing treatment in step 3 in a H2O2 etcher for secondary etching to completely eliminate the subsurface defect layer of the fused quartz element and passivate the optical surface to achieve effective and controllable removal of surface defects of the fused quartz element;

[0012] Step 5: Clean the fused quartz component after etching in step 3 with deionized water and ethanol. The operation steps are the same as step 1.

[0013] Preferably, the ethanol solution used in step 1 and step 3 is anhydrous ethanol.

[0014] Preferably, in step one, during ultrasonic cleaning with ethanol solution, the frequencies used in sequence are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 2 to 5 minutes.

[0015] Preferably, in the step 1, the ultrasonic cleaning in deionized water is divided into two cycles, and 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic waves are used to assist cleaning for 2 to 5 minutes per cycle, and the deionized water in the rinse tank is replaced after each cleaning cycle; after the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

[0016] Preferably, in step 2, the reactive ion etching uses a CHF3-Ar mixture, the etching rate is 2 μm / h, and the etching time is 80 min.

[0017] Preferably, in the inorganic acid cleaning process of step 2, the entire sample is immersed in a mixed inorganic acid of HNO3 and H2O2 in a volume ratio of 2:1, the treatment time is 80 minutes, the mass fraction of HNO3 is 70%, and the mass fraction of 40% H2O2 is 40%.

[0018] Preferably, in step 4, the mass fraction of H2O2 is 5% to 50%.

[0019] Preferably, in the step 2, the frequency of the high-frequency electric field for reactive ion etching is 12 to 25 MHz.

[0020] Preferably, in the step 2, the volume ratio of CHF3 and Ar in the reaction chamber for reactive ion etching is controlled to be 0.2-0.9:1.5 or 0.25-0.85:1.

[0021] Preferably, in step 2, the Ar inlet flow rate in the reaction chamber for reactive ion etching is selected to be 50 cm 3 / min~200cm 3 / min or 65cm 3 / min~180cm 3 / min.

[0022] Preferably, in step three, the atmosphere in the annealing chamber is dry air or nitrogen, the annealing temperature is 400-2000° C., and the annealing time is 1-20 hours.

[0023] The present invention includes at least the following beneficial effects: a convenient, fast and quality-controllable post-processing process is proposed, which is a combined surface treatment method for fused quartz components that combines reactive ion etching, high-temperature annealing and H2O2 etching. First, the surface defects of the fused quartz component are removed by reactive ion etching, and after cleaning, the component is subjected to high-temperature annealing to converge the sub-surface physical structure defects remaining after the reactive ion etching treatment, eliminate residual stress and densification, and at the same time, the impurity elements on the sub-surface are transferred to the near-surface, and then cleaned and dried; then the component surface is etched by H2O2 to further remove near-surface contamination defects and passivate the component surface.

[0024] Among them, since the high temperature annealing step can converge and reduce the residual defect layer, the time of the previous step of reactive ion etching can be shortened, the amount of harmful fluorine-containing gas is reduced, and a large amount of material removal can be avoided. In addition, the high temperature annealing treatment can remove the material densification and residual stress caused by the pre-treatment on the sub-surface of the component, and further eliminate the factors that restrict the laser damage resistance of the fused quartz component. At the same time, the present invention innovatively uses the high temperature annealing treatment to migrate the contamination defects remaining on the sub-surface of the component to the near surface of the component, which greatly reduces the burden of the next step of H2O2 etching. Finally, the surface defects are completely eliminated by H2O2 etching, and the surface is passivated, so as to achieve effective and controllable removal of the surface defects of the fused quartz component. Compared with the existing single technology and other combined technologies, the combined treatment method proposed by the present invention is more economical, clean and environmentally friendly, and because the last process converges with the etching reaction of H2O2 and SiO2, it will hardly introduce other negative effects, so it may have a more expected damage energy improvement effect than the mainstream etching process.

[0025] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic process flow diagram of a combined surface treatment method for a fused quartz component for improving the ability to resist laser damage provided in Examples 1 to 3;

[0027] Figure 2 A schematic diagram of the operation flow of a combined surface treatment method for a fused quartz component for improving the ability to resist laser damage provided in Examples 1 to 3;

[0028] Figure 3 The AFM three-dimensional topography image of the surface of the fused quartz component after treatment in Example 1 and its corresponding roughness value;

[0029] Figure 4 The AFM three-dimensional topography image of the surface of the fused quartz component after treatment in Example 2 and its corresponding roughness value;

[0030] Figure 5 The AFM three-dimensional topography image of the surface of the fused quartz component after treatment in Example 3 and its corresponding roughness value;

[0031] Figure 6 The AFM three-dimensional topography image of the fused quartz component surface after treatment in Comparative Example 1 and its corresponding roughness value;

[0032] Figure 7 The AFM three-dimensional topography image of the fused quartz component surface after treatment in Comparative Example 2 and its corresponding roughness value;

[0033] Figure 8 The AFM three-dimensional topography image of the fused quartz component surface after treatment in Comparative Example 3 and its corresponding roughness value;

[0034] Fig. 9 AFM three-dimensional morphology of the untreated fused quartz component surface and its corresponding roughness value. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0036] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0037] Example 1

[0038] like Figure 1 and Figure 2 As shown, this embodiment provides a combined surface treatment method for a fused quartz component for improving the ability to resist laser damage, comprising the following steps:

[0039] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes.

[0040] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 minutes per cycle. After each cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

[0041] Step 2: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 15 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.4:1.5, and the Ar inlet flow rate is selected to be 70 cm 3 / min, the gas outlet pressure is selected as 0.4Pa, the etching speed is 2μm / h, and the etching time is 1h. After etching, the entire sample is immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1, and the treatment time is 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry. Place the fused quartz element in the quartz inner tube of the high-temperature annealing furnace for high-temperature annealing, and fill the quartz inner tube with dry air to seal it, and anneal it at 500℃ for 2h.

[0042] Step 3, placing the fused quartz component cooled after high temperature annealing in a H2O2 etcher with a concentration of 30% for etching for 5 hours to completely eliminate the deteriorated layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0043] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 to 5 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0044] Example 2

[0045] This embodiment provides a combined surface treatment method for a fused quartz component to improve the ability to resist laser damage, comprising the following steps:

[0046] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes.

[0047] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 5 minutes per cycle. After each cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

[0048] Step 2: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 15 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.7:1.5, and the Ar inlet flow rate is selected to be 70 cm 3 / min, the gas outlet pressure is selected as 0.5Pa, the etching speed is 2μm / h, and the etching time is 1.5h. After etching, the entire sample is immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1, and the treatment time is 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry. Place the fused quartz element in the quartz inner tube of the high-temperature annealing furnace for high-temperature annealing, and fill the quartz inner tube with dry air to seal it, and anneal it at 600℃ for 4h.

[0049] Step 3, placing the fused quartz component cooled after high temperature annealing in a H2O2 etcher with a concentration of 30% for etching for 5 hours to completely eliminate the deteriorated layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0050] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 to 5 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0051] Example 3

[0052] This embodiment provides a combined surface treatment method for a fused quartz component to improve the ability to resist laser damage, comprising the following steps:

[0053] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes.

[0054] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 5 minutes per cycle. After each cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

[0055] Step 2: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 15 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.8:1.5, and the Ar inlet flow rate is selected to be 70 cm 3 / min, etching speed is 2μm / h, etching time is 3h. After etching, the whole sample is immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1 for 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry. Put the fused quartz element into the quartz inner tube of the high-temperature annealing furnace for high-temperature annealing, fill the quartz inner tube with dry air to seal it, and anneal it at 800℃ for 6h.

[0056] Step 3, placing the fused quartz component cooled after high temperature annealing in a H2O2 etcher with a concentration of 30% for etching for 5 hours to completely eliminate the deteriorated layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0057] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 to 5 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0058] The roughness and laser damage threshold of the fused quartz components after being processed in Example 1 to Example 3 were measured respectively, and the following table was obtained:

[0059]

[0060] The AFM three-dimensional morphology images of the fused quartz component surface after treatment in Example 1 to Example 3 and their corresponding roughness values ​​are shown in FIG. Figure 3 , Figure 4 and Figure 5As shown in the figure, the AFM three-dimensional morphology of the untreated fused quartz component surface and its corresponding roughness value are shown in Fig. 9 shown.

[0061] Comparative Example 1

[0062] This embodiment provides a combined surface treatment method for a fused quartz component to improve the ability to resist laser damage, comprising the following steps:

[0063] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 2 minutes;

[0064] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 minutes per cycle. After each cleaning cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles;

[0065] Step 2: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are a CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 13 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.4:1.5, and the Ar inlet flow rate is selected to be 60 cm 3 / min, the gas outlet pressure is selected as 0.4Pa, the etching speed is 2μm / h, and the etching time is 1h. After etching, the sample is completely immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1 for 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry;

[0066] Step 3: Place the fused quartz component after reactive ion etching in a H2O2 etcher with a concentration of 30% for 3 hours to completely eliminate the deterioration layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0067] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used in sequence are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 2 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0068] Comparative Example 2

[0069] This embodiment provides a combined surface treatment method for a fused quartz component to improve the ability to resist laser damage, comprising the following steps:

[0070] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 3 minutes.

[0071] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 3 minutes per cycle. After each cleaning cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles;

[0072] Step 3: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 15 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.7:1.5, and the Ar inlet flow rate is selected to be 70 cm 3 / min, the gas outlet pressure is selected as 0.5Pa, the etching speed is 2μm / h, and the etching time is 2h. After etching, the sample is completely immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1 for 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry;

[0073] Step 3, placing the fused quartz component after reactive ion etching in a H2O2 etcher with a concentration of 30% for 4 hours to completely eliminate the deterioration layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0074] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used in sequence are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 3 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 3 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0075] Comparative Example 3

[0076] This embodiment provides a combined surface treatment method for a fused quartz component to improve the ability to resist laser damage, comprising the following steps:

[0077] Step 1: Ultrasonic cleaning of fused quartz components. First, ultrasonic cleaning is performed in anhydrous ethanol solution to remove oil stains, dust, etc. on the surface of the components. The frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes.

[0078] Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 5 minutes per cycle. After each cycle, the deionized water in the rinsing tank is replaced. After the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

[0079] Step 2: Place the cleaned fused quartz element in a parallel plate discharge etcher for reactive ion etching, wherein the reactive ions are CHF3-Ar mixture, the high-frequency electric field frequency of the reactive ion etching is 15 MHz, the volume ratio of CHF3 and Ar is controlled to be 0.8:1.5, and the Ar inlet flow rate is selected to be 70 cm 3 / min, the gas outlet pressure is selected as 0.5Pa, the etching speed is 2μm / h, and the etching time is 3h. After etching, the sample is completely immersed in a mixed inorganic acid of 70% HNO3 and 40% H2O2 with a volume ratio of 2:1 for 80 minutes. Dissolve the metal impurities that may remain in the reactive ion etching process, then wash with deionized water and dry.

[0080] Step 3, placing the fused quartz component after reactive ion etching in a H2O2 etcher with a concentration of 30% for 5 hours to completely eliminate the deterioration layer generated by the reactive ion etching pre-treatment process and reduce the sub-surface defect density to a minimum;

[0081] Step 4: Ultrasonic cleaning of the fused quartz component after H2O2 etching. When ultrasonic cleaning with ethanol solution and deionized water, the frequencies used are 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz, and the working time of each frequency is 5 minutes. Deionized rinsing is divided into two cycles, using 20kHz, 28kHz, 45kHz, 60kHz, 80kHz, 100kHz, and 135kHz ultrasonic assisted cleaning for 2 to 5 minutes per cycle. After each cycle of cleaning, replace the deionized water in the rinsing tank.

[0082] The laser damage thresholds of the fused quartz components repaired in Example 1 to Example 3 were tested respectively, and the laser damage threshold test results were shown in the following table:

[0083]

[0084] The AFM three-dimensional morphology images of the fused quartz component surfaces after treatment in Comparative Examples 1 to 3 and their corresponding roughness values ​​are shown in Figure 6 , Figure 7 and Figure 8 shown.

[0085] Comparative Example 4

[0086] In this comparative example, the reactive ion etching time for the fused quartz component is 1 hour, and the H2O2 etching is not performed on the fused quartz component. The remaining operations are the same as those in Example 3.

[0087] Comparative Example 5

[0088] In this comparative example, the reactive ion etching time for the fused quartz component is 2 hours, and the H2O2 etching is not performed on the fused quartz component. The remaining operations are the same as those in Example 3.

[0089] Comparative Example 6

[0090] In this comparative example, the reactive ion etching time for the fused quartz component is 3 hours, and the H2O2 etching is not performed on the fused quartz component. The remaining operations are the same as those in Example 3.

[0091] Comparative Example 7

[0092] In this comparative example, reactive ion etching was not performed on the fused quartz component. The H2O2 etching time for the fused quartz component was 3 hours. The remaining operations were the same as those in Example 3.

[0093] Comparative Example 8

[0094] In this comparative example, reactive ion etching was not performed on the fused quartz component. The H2O2 etching time for the fused quartz component was 4 hours. The remaining operations were the same as those in Example 3.

[0095] Comparative Example 9

[0096] In this comparative example, reactive ion etching was not performed on the fused quartz component. The H2O2 etching time for the fused quartz component was 5 hours. The remaining operations were the same as those in Example 3.

[0097] The laser damage thresholds of the fused quartz components repaired by Comparative Examples 4 to 9 were tested respectively, and the laser damage threshold test results were shown in the following table:

[0098]

[0099] From the above table and Figure 3-Figure 9 It can be seen that after the surface of the fused quartz optical element is treated by the reactive ion etching method, the laser damage threshold of the surface of the fused quartz element will be affected, and as the etching time gradually increases, the damage threshold also increases, but after the reactive ion etching, high temperature annealing and H2O2 etching are combined, the damage threshold of the fused quartz surface is significantly increased. In summary, the results of the above embodiments show that by reasonably controlling the process, the combined treatment method of reactive ion etching, high temperature annealing and H2O2 etching can effectively remove the chemical structure defects on the surface of the fused quartz element, improve the surface quality of the fused quartz element, and thus improve the laser damage threshold of the fused quartz element.

[0100] The number of devices and processing scales described here are used to simplify the description of the present invention. Applications, modifications and variations of the present invention will be obvious to those skilled in the art.

[0101] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A combined surface treatment method for fused quartz components to improve laser damage resistance, characterized in that: The following steps are involved: Step 1: ultrasonically clean the fused quartz element in ethanol to remove dust and oil stains on the surface, and then ultrasonically clean the fused quartz element in deionized water; Step 2: placing the fused quartz element cleaned in step 1 in a parallel plate discharge etcher for reactive ion etching, cleaning the surface of the element with inorganic acid after etching, and then cleaning with deionized water and drying; Step 3: Place the cleaned fused quartz component in a high temperature annealing furnace for high temperature annealing. The atmosphere in the annealing chamber is dry air or nitrogen. The annealing temperature is 400-800°C and the annealing time is 1-20 h. Step 4: Place the fused quartz component after high temperature annealing in a H2O2 etcher for secondary etching, with the mass fraction of H2O2 being 5% to 50%; Step 5: Clean the fused quartz component after etching in step 3 with deionized water and ethanol. The operation steps are the same as step 1.

2. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: The ethanol solution used in step 1 and step 5 is anhydrous ethanol.

3. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In step 1, when ultrasonic cleaning is performed with ethanol solution, the frequencies used in sequence are 20 kHz, 28 kHz, 45 kHz, 60 kHz, 80 kHz, 100 kHz, and 135 kHz, and the working time of each frequency is 2 to 5 min.

4. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In the step 1, the ultrasonic cleaning in deionized water is divided into two cycles, and 20 kHz, 28 kHz, 45 kHz, 60 kHz, 80 kHz, 100 kHz, and 135 kHz ultrasonic waves are used to assist cleaning for 2 to 5 minutes per cycle. After each cleaning cycle, the deionized water in the rinse tank is replaced; after the last cleaning, the surface of the fused quartz element is rinsed with flowing deionized water to remove residual moisture and particles.

5. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In step 2, reactive ion etching uses a CHF3-Ar mixture, the etching rate is 2 μm / h, and the etching time is 80 min.

6. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In the inorganic acid cleaning process of step 2, all samples are immersed in a mixed inorganic acid of HNO3 and H2O2 with a volume ratio of 2:1, the treatment time is 80 min, the mass fraction of HNO3 is 70%, and the mass fraction of H2O2 is 40%.

7. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In the step 2, the frequency of the high-frequency electric field for reactive ion etching is 12-25 MHz; the volume ratio of CHF3 and Ar in the reaction chamber for reactive ion etching is controlled to be 0.2-0.9:1.5 or 0.25-0.85:

1.

8. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 1, characterized in that: In step 2, the Ar inlet flow rate in the reaction chamber for reactive ion etching is selected to be 50 cm 3 / min~200cm 3 / min.

9. The combined surface treatment method for fused quartz components for improving laser damage resistance according to claim 8, characterized in that: In step 2, the Ar inlet flow rate in the reaction chamber for reactive ion etching is selected to be 65 cm 3 / min~180cm 3 / min.

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