Multi-layer coating method of nano optical lens for semiconductor manufacturing and application

Abstract

The invention relates to the technical field of optical thin films, in particular to a multi-layer coating method of a nano optical lens for semiconductor manufacturing and application, in order to improve the stain resistance and the anti-reflection performance of the optical lens, multi-layer coating treatment is carried out on the surface of the optical lens, and after the lens is polished and cleaned, the surface of the optical lens is coated with the nano optical lens. Further etching and activating treatment is carried out on the surface of the glass substrate, so that the contact area of a subsequent coating layer is increased, occlusion points are increased, and the bonding strength between the coating and the glass substrate is improved; moreover, a layer of silicon film is sputtered on the surface of the glass substrate, and the silicon layer is processed in a hydrogen and argon mixed atmosphere and an SF6 and argon mixed gas atmosphere respectively, so that different properties of the silicon layer are modified, the bonding performance between the silicon layer and the glass substrate is improved, and on the basis, a layer of fluorine-calcium layer with high light transmittance is sputtered on the surface of the glass substrate, so that the glass substrate has high light transmittance. Therefore, the low reflection performance of the lens is finally realized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical thin films, and specifically to a multi-layer coating method and application of nano-optical lenses for semiconductor manufacturing. Background Art

[0002] With the continuous development of China's electronic technology, semiconductor products have also occupied an increasingly important position in our daily lives. However, currently in the process of semiconductor preparation, optical lenses, as core components, participate in the entire process of semiconductor preparation and have a crucial impact on the preparation quality and yield of semiconductors. For example, in the laser processing during semiconductor preparation, it has a high impact on the performance of optical lenses such as light transmittance, refractive index, and reflectivity. Therefore, in order to further improve the yield of semiconductor products, it is necessary to conduct further research and improvement on optical lenses. Summary of the Invention

[0003] The purpose of the present invention is to provide a multi-layer coating method and application of nano-optical lenses for semiconductor manufacturing to solve the problems raised in the prior art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A multi-layer coating method of nano-optical lenses for semiconductor manufacturing, including the following steps: S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use. S2. Place the polished glass lens in deionized water, ultrasonically clean it for 10 - 20 minutes, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 10 - 20 minutes, and then dry it for use. S3. Place the cleaned glass lens in etching gas and activation gas, control the working pressure to be 0.05 - 0.15 Pa, etch and activate for 15 - 30 minutes, evacuate, then introduce pure activation gas again, control the working pressure to be 0.1 - 0.25 Pa, continue to process for 5 - 10 minutes, and then take it out to obtain an activated glass lens. S4. Place the activated glass lens in a vacuum sputtering reaction coating machine, evacuate, then introduce argon gas into it, control the pressure to be 0.01 - 0.1 Pa, conduct medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and the sputtering power is 5 - 10 Kw. S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere, control the vacuum degree to be 0.001 - 0.1 Pa, then control the working voltage to be 1.2 - 3 kV, process for 2 - 4 minutes, form a silicon hydride layer on the lens surface, then switch the working gas atmosphere to a mixed gas atmosphere of SF6 and argon gas, maintain the working pressure, continue to process for 30 - 45 seconds, form a fluorosilicon layer, and then take it out for use. S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa. After sputtering, a nano - optical lens for semiconductor manufacturing is obtained.

[0005] Furthermore, in step S3, the etching gas is C2F6; the activation gas is oxygen.

[0006] Furthermore, in step S3, the volume ratio of the etching gas to the activation gas is (1 - 4):1.

[0007] Furthermore, in step S3, during etching and activation, the working voltage is 800 - 1200 V, and the temperature is raised to 350 - 450 °C.

[0008] Furthermore, in step S5, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio of hydrogen to argon is (0.5 - 2):10.

[0009] Furthermore, in step S5, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is (0.01 - 0.1):10.

[0010] Furthermore, in step S6, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is (0.1 - 1.2):10.

[0011] Furthermore, in step S6, during sputtering, control the working temperature to be 15 - 25 °C, and the sputtering power to be 180 - 800 W.

[0012] Furthermore, the coating method can be used for surface coating of optical lenses for semiconductor manufacturing.

[0013] Compared with the prior art, the beneficial effects of the present invention are: In order to improve the stain - resistance and anti - reflection properties of the optical lens, the present invention conducts multi - layer coating treatment on the surface of the optical lens. After polishing and cleaning the lens, it conducts further etching and activation treatment on its surface. Under the action of low - temperature plasma, it further removes the residual organic pollution on its surface, thereby improving the coating quality in subsequent steps, avoiding voids or peeling in the coating layer. And after the etching and activation treatment, a nano - microstructure will be formed on the surface of the quartz glass, thereby increasing the contact area of the subsequent coating layer, increasing the biting points, and improving the bonding strength between the coating and the glass substrate; Moreover, after the lens is etched, a silicon film is sputtered on its surface, and the silicon layer is modified in different gas atmospheres. First, the silicon layer is hydrosilylated in a mixed atmosphere of hydrogen and argon. The refractive index of the hydrosilicon layer is generally between 1.45 and 1.48, which is similar to that of the quartz glass substrate. It has high light transmittance and hardness similar to that of quartz glass, and can have good bonding strength with quartz glass. On this basis, the present invention further uses a mixed gas atmosphere of SF6 and argon to treat the silicon layer. After forming a fluorosilicon layer, a fluorocalcium layer with high light transmittance is sputtered on its surface again, thus finally realizing the low reflection performance of the lens. Detailed implementation mode

[0014] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0015] Example 1. A multi-layer coating method for a nano-optical lens used in semiconductor manufacturing, comprising the following steps: S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 minutes, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 minutes, and then dry it for use; S3. Place the cleaned glass lens in etching gas and activation gas, control the working pressure to be 0.05 Pa, when etching and activating, the working voltage is 800 V, heat up to 450 °C, after etching and activating for 30 minutes, evacuate, and then introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 minutes, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 1:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine, evacuate, and then introduce argon into it, control the pressure to be 0.01 Pa, perform medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and sputter with a sputtering power of 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere, control the vacuum degree to be 0.001 Pa, then control the working voltage to be 1.2 kV, after processing for 4 minutes, a silicon hydride layer is formed on the lens surface, and then the working gas atmosphere is switched to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 seconds, form a fluorosilicon layer, and then take it out for use; Among them, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio is 0.5:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.01:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1~2.5 Pa, control the working temperature to be 20 °C, and the sputtering power to be 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0016] Example 2. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, including the following steps: Compared with Example 1, this example increases the volume ratio of the etching gas in step S3; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for later use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 min, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 min, and then dry it for later use; S3. Place the cleaned glass lens in an etching gas and an activation gas, control the working pressure to be 0.05 Pa. When etching and activating, the working voltage is 800 V, heat up to 450 °C, etch and activate for 30 min, then evacuate, and introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 min, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 4:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating, introduce argon into it, control the pressure to be 0.01 Pa, perform medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and the sputtering power is 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere. After controlling the vacuum degree to be 0.001 Pa, control the working voltage to be 1.2 kV, process for 4 min, and after forming a silicon hydride layer on the lens surface, switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 s, form a fluorosilicon layer, and then take it out for later use; Among them, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio is 0.5:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.01:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, the working temperature to be 20 °C, and the sputtering power to be 180 W. After the sputtering is completed, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0017] Example 3. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, comprising the following steps: Compared with Example 2, this example increases the working voltage of etching activation in step S3 and reduces the etching activation temperature; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 minutes, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 minutes, and then dry it for use; S3. Place the cleaned glass lens in an etching gas and an activation gas, control the working pressure to be 0.05 Pa. When etching and activating, the working voltage is 1200 V, heat up to 350 °C, etch and activate for 30 minutes, evacuate the air, and then introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 minutes, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 4:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating the air, introduce argon into it, control the pressure to be 0.01 Pa, and perform medium-frequency magnetron sputtering on it. Use a high-purity silicon target as the sputtering source, and the sputtering power is 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere. After controlling the vacuum degree to be 0.001 Pa, control the working voltage to be 1.2 kV, process for 4 minutes, form a silicon hydride layer on the lens surface, and then switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 seconds, form a fluorosilicon layer, and then take it out for use; Among them, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio is 0.5:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.01:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, the working temperature to be 20 °C, and the sputtering power to be 180 W. After the sputtering is completed, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0018] Example 4. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, comprising the following steps: Compared with Example 3, the volume ratio of hydrogen in step S5 is increased in this example; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 min, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 min, and then dry it for use; S3. Place the cleaned glass lens in an etching gas and an activation gas, control the working pressure to be 0.05 Pa, when etching and activating, the working voltage is 1200 V, heat up to 350 °C, etch and activate for 30 min, evacuate the air, and then introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 min, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 4:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating the air, introduce argon into it, control the pressure to be 0.01 Pa, perform medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and sputter with a sputtering power of 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere. After controlling the vacuum degree to be 0.001 Pa, control the working voltage to be 1.2 kV, process for 4 min, form a silicon-hydrogen layer on the lens surface, then switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 s, form a fluorosilicon layer, and then take it out for use; Among them, the mixed gas is a mixed gas of hydrogen and argon with a volume ratio of 2:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.01:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, the working temperature to be 20 °C, and the sputtering power to be 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0019] Example 5. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, including the following steps: Compared with Example 4, the volume ratio of SF6 in step S5 is increased in this example; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 min, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 min, and then dry it for use; S3. Place the cleaned glass lens in an etching gas and an activation gas, control the working pressure to be 0.05 Pa, when etching and activating, the working voltage is 1200 V, heat up to 350 °C, after etching and activating for 30 min, evacuate the air, and then introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 min, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 4:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating the air, introduce argon into it, control the pressure to be 0.01 Pa, perform medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and sputter with a sputtering power of 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere. After controlling the vacuum degree to be 0.001 Pa, control the working voltage to be 1.2 kV, process for 4 min, form a silicon hydride layer on the lens surface, and then switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 s, form a fluorosilicon layer, and then take it out for use; Among them, the mixed gas is a mixed gas of hydrogen and argon with a volume ratio of 2:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, control the working temperature to be 20 °C, and the sputtering power to be 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0020] Example 6. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, comprising the following steps: Compared with Example 5, the volume ratio of SF6 in step S6 is increased in this example; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 min, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 min, and then dry it for later use; S3. Place the cleaned glass lens in an etching gas and an activation gas, control the working pressure to be 0.05 Pa, when etching and activating, the working voltage is 1200 V, heat up to 350 °C, etch and activate for 30 min, then evacuate the air, and introduce pure activation gas again, control the working pressure to be 0.1 Pa, continue to process for 10 min, and then take it out to obtain an activated glass lens; Among them, the etching gas is C2F6; the activation gas is oxygen; the volume ratio of the etching gas to the activation gas is 4:1; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating the air, introduce argon into it, control the pressure to be 0.01 Pa, and perform medium-frequency magnetron sputtering on it. Use a high-purity silicon target as the sputtering source for sputtering, and the sputtering power is 5 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed gas atmosphere. After controlling the vacuum degree to be 0.001 Pa, control the working voltage to be 1.2 kV, process for 4 min, form a silicon hydride layer on the lens surface, then switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 s, form a fluorosilicon layer, and then take it out for later use; Among them, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio is 2:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, control the working temperature to be 20 °C, and the sputtering power to be 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 1.2:10.

[0021] Comparative Example 1. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, comprising the following steps: Compared with Example 1, this comparative example does not perform the treatments of steps S3 - S5; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 minutes, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 minutes, and then dry it for use; S3. Place the lens in a vacuum chamber, use a CaF2 ceramic target as the sputtering source. After evacuating the air, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to be 0.1 - 2.5 Pa, control the working temperature to be 20 °C, and the sputtering power to be 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0022] Comparative Example 2. A multi-layer coating method for a nano-optical lens for semiconductor manufacturing, comprising the following steps: Compared with Example 1, this comparative example does not perform step S3; S1. Grind the surface of the glass lens, and after rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water, ultrasonically clean it for 15 minutes, dry the surface with hot air, and then place it in acetone and absolute ethanol respectively, ultrasonically clean it for 15 minutes, and then dry it for use; S3. Place the glass lens in a vacuum sputtering reaction coating machine. After evacuating the air, introduce argon into it, control the pressure to be 0.01 Pa, perform medium-frequency magnetron sputtering on it, use a high-purity silicon target as the sputtering source, and sputter with a sputtering power of 5 Kw; S4. Place the lens with a sputtered silicon layer on its surface in a mixed gas atmosphere. After controlling the vacuum degree to 0.001 Pa, control the working voltage to 1.2 kV. After processing for 4 min, a silicon hydride layer is formed on the lens surface. Then, switch the working gas atmosphere to a mixed atmosphere of SF6 and argon, maintain the working pressure, and continue to process for 30 s to form a fluorosilicon layer. Take it out and set it aside for later use; Among them, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio is 0.5:10; in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.01:10; S5. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating, introduce a mixed gas atmosphere of argon and SF6 into it. Control the working pressure to 0.1 - 2.5 Pa, control the working temperature to 20 °C, and the sputtering power to 180 W. After sputtering, a nano-optical lens for semiconductor manufacturing is obtained; Among them, in the mixed gas of SF6 and argon, the volume ratio of SF6 to argon is 0.1:10.

[0023] Detection: Prepare the nano-optical lenses prepared in Examples 1 - 6 and Comparative Examples 1 - 2 into samples with a silicon layer thickness of 120 nm and a fluorocalcium layer thickness of 70 nm. Use a spectroscopic ellipsometer to detect the refractive index of the thin film; use a UV-visible spectrophotometer to test the UV light transmittance; Heat the above specimens at a rate of 1.5 °C / min to 500 °C and hold for 15 min, then cool to room temperature at a rate of 1.5 °C / min again and hold for 15 min. Repeat this step 30 times. Then, conduct an adhesion test on the lens surface coating according to GB / T 9286 - 1998. The test results are shown in the following table;

[0024] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-layer coating method for nano-optical lenses used in semiconductor manufacturing, characterized in that, It includes the following steps: S1. Grind the surface of the glass lens. After rough polishing and fine polishing, set it aside for use; S2. Place the polished glass lens in deionized water. After ultrasonic cleaning for 10 - 20 min, dry the surface with hot air. Then place it in acetone and absolute ethanol respectively, ultrasonic clean for 10 - 20 min, and then dry for later use; S3. Place the cleaned glass lens in etching gas and activation gas. Control the working pressure to be 0.05 - 0.15 Pa. After etching and activation for 15 - 30 min, evacuate the vacuum. Then introduce pure activation gas again, control the working pressure to be 0.1 - 0.25 Pa, continue to process for 5 - 10 min, and then take it out to obtain an activated glass lens; S4. Place the activated glass lens in a vacuum sputtering reaction coating machine. After evacuating the vacuum, introduce argon gas into it, control the pressure to be 0.01 - 0.1 Pa, perform medium - frequency magnetron sputtering on it, use a high - purity silicon target as the sputtering source, and the sputtering power is 5 - 10 Kw; S5. Place the lens with a silicon layer sputtered on its surface in a mixed - gas atmosphere. After controlling the vacuum degree to be 0.001 - 0.1 Pa, control the working voltage to be 1.2 - 3 kV, process for 2 - 4 min to form a silicon - hydrogen layer on the lens surface. Then switch the working gas atmosphere to a mixed - gas atmosphere of SF6 and argon, maintain the working pressure, continue to process for 30 - 45 s to form a fluorosilicon layer, and then take it out for later use; S6. Place the lens with a fluorosilicon layer formed on its surface in a vacuum chamber. Use a CaF2 ceramic target as the sputtering source. After evacuating the vacuum, introduce a mixed - gas atmosphere of argon and SF6 into it, control the working pressure to be 0.1 - 2.5 Pa. After sputtering, obtain a nano - optical lens for semiconductor manufacturing; 2. The multi-layer coating method of the nano-optical lens for semiconductor manufacturing according to claim 1, wherein: In step S3, the etching gas is C2F6; the activation gas is oxygen.

3. The multi-layer coating method of the nano-optical lens for semiconductor manufacturing according to claim 1, wherein: In step S3, the volume ratio of the etching gas to the activation gas is (1 - 4):

1.

4. The multi-layer coating method of the nano-optical lens for semiconductor manufacturing according to claim 1, characterized in that: In step S3, during etching and activation, the working voltage is 800 - 1200 V, and the temperature is raised to 350 - 450 °C.

5. A multi-layer coating method for a nano-optical lens used in semiconductor manufacturing according to claim 1, characterized in that: In step S5, the mixed gas is a mixed gas of hydrogen and argon, and the volume ratio of hydrogen to argon is (0.5 - 2):

10.

6. The multi-layer coating method of the nano-optical lens for semiconductor manufacturing according to claim 1, characterized in that: In the mixed - gas of SF6 and argon in step S5, the volume ratio of SF6 to argon is (0.01 - 0.1):

10.

7. A multi-layer coating method for a nano-optical lens used in semiconductor manufacturing according to claim 1, characterized in that: In the mixed - gas of SF6 and argon in step S6, the volume ratio of SF6 to argon is (0.1 - 1.2):

10.

8. A multi-layer coating method for a nano-optical lens used in semiconductor manufacturing according to claim 1, characterized in that: In step S6, during sputtering, control the working temperature to be 15 - 25 °C, and the sputtering power is 180 - 800 W.

9. Use of a multi-layer coating method according to any one of claims 1 to 8, characterized in that: The coating method is used for surface coating of optical lenses for semiconductor manufacturing.

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