A 365nm ultraviolet narrow-band filter for a photoetching machine and a preparation method thereof

Abstract

The application relates to the technical field of optical elements, and discloses a 365nm ultraviolet narrow-band filter for a photoetching machine and a preparation method thereof, which comprises a glass substrate, one side of the glass substrate is provided with a high-reflection film layer, and the other side is provided with an antireflection film layer; the high-reflection film layer comprises alternately-stacked SiO2 layers and Ta2O5 layers, the film is plated by using an ion sputtering plating machine, and is prepared by using an auxiliary ion source in a deposition process. Through the technical scheme, the problem that the 365nm transmittance of the filter in the prior art is low and the service life is short is solved.

Description

Technical Field

[0001] This invention relates to the field of optical element technology, specifically to a 365nm ultraviolet narrowband filter for lithography machines and its preparation method. Background Technology

[0002] 365nm ultraviolet narrowband filters require extremely high transmittance at 365nm, with transmittance of less than 1% for other ultraviolet wavelengths, a cutoff range of 450nm to 700nm, and an average cutoff rate close to 100%. 365nm ultraviolet narrowband filters can be used as violet-band filters in banknote detectors, and can also be applied in various fields such as gem identification and medical equipment.

[0003] A utility model patent, titled "A 365nm Narrowband Ultraviolet Filter Element" (application number 201621030136.8), proposes a filter using HfO2 double-sided vacuum coating, achieving a maximum transmittance of 95% at 365nm and an absorption and scattering loss of 5%. However, the transmittance of the filter for 365nm ultraviolet light directly affects the accuracy of testing. The existing technology's 95% transmittance cannot guarantee the accuracy requirements of the filter in various application fields, especially in lithography machines where the transmittance requirements are even higher. Therefore, the existing filter technology is not suitable for lithography machines and cannot meet the requirements of high-precision ultraviolet lithography machines, which require a transmittance greater than 98% and a k-value less than 1.8%.

[0004] In addition, the lifespan of filters in existing technology is relatively short. Excessive repeated rubbing of the filter with slight external force can damage the film layer. Summary of the Invention

[0005] This invention proposes a 365nm ultraviolet narrowband filter for lithography machines and its preparation method, which solves the problems of low transmittance and short service life of existing filters at 365nm.

[0006] The technical solution of the present invention is as follows:

[0007] A 365nm ultraviolet narrowband filter for a lithography machine includes a glass substrate. One side of the glass substrate is provided with a high-reflectivity film layer, and the other side is provided with an anti-reflection film layer. The high-reflectivity film layer includes alternating SiO2 layers and Ta2O5 layers.

[0008] As a further technical solution, the SiO2 layer and Ta2O5 layer together are 40-60 layers, with odd-numbered layers being Ta2O5 layers and even-numbered layers being SiO2 layers.

[0009] As a further technical solution, the SiO2 layer and Ta2O5 layer together comprise 40 layers.

[0010] As a further technical solution, in the odd-numbered layers, the thickness of layers 1, 3, 5, 7, 9, 11, 13, and 15 is 28.72 nm, and the thickness of layers 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 is 42.94 nm.

[0011] As a further technical solution, in the even-numbered layers, the thickness of the 2nd, 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th, 20th, 22nd, 24th, and 26th layers is 58.48nm, and the thickness of the 28th, 30th, 32nd, 34th, 36th, 38th, and 40th layers is 70.13nm.

[0012] As a further technical solution, the antireflective coating layer includes a Ta2O5 layer with a thickness of 30.26 nm and a SiO2 layer with a thickness of 60.82 nm.

[0013] As a further technical solution, the substrate glass is Eagle XG. Using Eagle XG as the substrate glass makes the Ta2O5 coating process more controllable and the adhesion to the coating stronger.

[0014] The present invention also proposes a method for preparing the 365nm ultraviolet narrowband filter for the lithography machine, wherein the coating is performed by an ion sputtering coating machine and an auxiliary ion source is used during the deposition process.

[0015] As a further technical solution, the process parameters of the ion sputtering coating machine are as follows: substrate temperature 110-120℃, substrate pressure 1.2-1.3×10⁻⁶. -4 Pa, Ta₂O₅ working pressure 1.3-1.4×10 -2 Pa, SiO2 working pressure 0.9-1.0×10 - 2 Pa, sputtering source voltage 1200-1300eV, sputtering source current 700-800mA.

[0016] As a further technical solution, the process parameters of the auxiliary ion source are as follows: auxiliary source ion beam energy 1400-1500eV, auxiliary source ion beam current 1200-1300mA, and auxiliary source oxygen flow rate 40-50sccm.

[0017] The working principle and beneficial effects of this invention are as follows:

[0018] 1. The 365nm ultraviolet narrowband filter of this invention uses Ta2O5 as a high-refractive-index material, which has the advantages of high hardness, good stability, and high refractive index. Compared with the existing technology using HfO2, the material cost is reduced by one-tenth. With a thinner thickness and fewer layers, the filter obtained by this invention has a transmittance of ≥98.5% for 365nm ultraviolet light and an absorption and scattering loss of ≤1.5%, which can meet the requirements of high-precision ultraviolet lithography machines, and its efficiency is improved by 17%-20% compared with the existing technology.

[0019] 2. In this invention, a high-power radio frequency ion source assists in the vacuum evaporation of Ta2O5 material, controlling the absorption and scattering K-values ​​of the Ta2O5 thin film to within 1.5%. This invention ensures the optical and mechanical properties of the thin film by controlling the coating process; the ion beam current of the auxiliary ion source is controlled at 1200-1300 mA, the ion beam energy at 1400-1500 eV, and the oxygen flow rate at 40-50 sccm. Too low a parameter will result in a large absorption loss, while too high a parameter will lead to a decrease in refractive index and poor mechanical properties of the thin film. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] A 365nm ultraviolet narrowband filter for a lithography machine includes an Eagle XG glass substrate. One side of the glass substrate is provided with a high-reflectivity film layer, and the other side is provided with an anti-reflection film layer. The anti-reflection film layer includes a Ta2O5 layer with a thickness of 30.26nm and a SiO2 layer with a thickness of 60.82nm. The high-reflectivity film layer includes alternating SiO2 layers and Ta2O5 layers, with a total of 40 SiO2 and Ta2O5 layers. Odd-numbered layers are Ta2O5 layers, and even-numbered layers are SiO2 layers.

[0023] In the odd-numbered layers, the thickness of layers 1, 3, 5, 7, 9, 11, 13, and 15 is 28.72 nm, and the thickness of layers 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 is 42.94 nm.

[0024] In the even-numbered layers, the thickness of layers 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, and 26 is 58.48 nm, and the thickness of layers 28, 30, 32, 34, 36, 38, and 40 is 70.13 nm.

[0025] The coating was performed using an ion sputtering coating machine, with an auxiliary ion source used during the deposition process. The process parameters are shown in Tables 1 and 2.

[0026] A peel strength of not less than 2.94 N / cm is used for a 2cm wide strip. 2 The adhesive tape was firmly attached to the surface of the film. The film was stretched vertically and rapidly 40 times, and the film did not peel off or get damaged.

[0027] Table 1. Process parameters of the ion sputtering coating machine in Example 1

[0028] Base pressure / Pa <![CDATA[1.2×10 -4 ]]> <![CDATA[Ta₂O₅ Working Pressure / Pa]]> <![CDATA[1.3×10 -2 ]]> <![CDATA[SiO2 Working Pressure / Pa]]> <![CDATA[0.9×10 -2 <!-- 2 -->]]> sputtering source voltage / eV 1200 Sputtering source current / mA 700

[0029] Table 2 Process parameters of the auxiliary ion source in Example 1

[0030] Auxiliary source ion beam current / mA 1200 Auxiliary source oxygen flow rate / sccm 40

[0031] Example 2

[0032] A 365nm ultraviolet narrowband filter for a lithography machine includes an Eagle XG glass substrate. One side of the glass substrate is provided with a high-reflectivity film layer, and the other side is provided with an anti-reflection film layer. The anti-reflection film layer includes a Ta2O5 layer with a thickness of 30.26nm and a SiO2 layer with a thickness of 60.82nm. The high-reflectivity film layer includes alternating SiO2 layers and Ta2O5 layers, with a total of 40 SiO2 and Ta2O5 layers. Odd-numbered layers are Ta2O5 layers, and even-numbered layers are SiO2 layers.

[0033] In the odd-numbered layers, the thickness of layers 1, 3, 5, 7, 9, 11, 13, and 15 is 28.72 nm, and the thickness of layers 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 is 42.94 nm.

[0034] In the even-numbered layers, the thickness of layers 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, and 26 is 58.48 nm, and the thickness of layers 28, 30, 32, 34, 36, 38, and 40 is 70.13 nm.

[0035] The coating was performed using an ion sputtering coating machine, with an auxiliary ion source used during the deposition process. The process parameters are shown in Tables 3 and 4.

[0036] A peel strength of not less than 2.94 N / cm is used for a 2cm wide strip. 2The adhesive tape was firmly attached to the surface of the film. The film was stretched vertically and rapidly 40 times, and the film did not peel off or get damaged.

[0037] Table 3 Process parameters of the ion sputtering coating machine in Example 2

[0038] Base pressure / Pa <![CDATA[1.3×10 -4 ]]> <![CDATA[Ta₂O₅ Working Pressure / Pa]]> <![CDATA[1.4×10 -2 ]]> <![CDATA[SiO2 Working Pressure / Pa]]> <![CDATA[1.0×10 -2 ]]> sputtering source voltage / eV 1300 Sputtering source current / mA 800

[0039] Table 4. Process parameters of the auxiliary ion source in Example 2

[0040] Auxiliary source ion beam current / mA 1300 Auxiliary source oxygen flow rate / sccm 50

[0041] Example 3

[0042] A 365nm ultraviolet narrowband filter for a lithography machine includes an Eagle XG glass substrate. One side of the glass substrate is provided with a high-reflectivity film layer, and the other side is provided with an anti-reflection film layer. The anti-reflection film layer includes a Ta2O5 layer with a thickness of 30.26nm and a SiO2 layer with a thickness of 60.82nm. The high-reflectivity film layer includes alternating SiO2 layers and Ta2O5 layers, with a total of 40 SiO2 and Ta2O5 layers. Odd-numbered layers are Ta2O5 layers, and even-numbered layers are SiO2 layers.

[0043] In the odd-numbered layers, the thickness of layers 1, 3, 5, 7, 9, 11, 13, and 15 is 28.72 nm, and the thickness of layers 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 is 42.94 nm.

[0044] In the even-numbered layers, the thickness of layers 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, and 26 is 58.48 nm, and the thickness of layers 28, 30, 32, 34, 36, 38, and 40 is 70.13 nm.

[0045] The coating was performed using an ion sputtering coating machine, with an auxiliary ion source used during the deposition process. The process parameters are shown in Tables 5 and 6.

[0046] A peel strength of not less than 2.94 N / cm is used for a 2cm wide strip. 2 The adhesive tape was firmly attached to the surface of the film. The film was stretched vertically and rapidly 40 times, and the film did not peel off or get damaged.

[0047] Table 5. Process parameters of the ion sputtering coating machine in Example 3

[0048]

[0049]

[0050] Table 6. Process parameters of the auxiliary ion source in Example 3

[0051] Auxiliary source ion beam current / mA 1250 Auxiliary source oxygen flow rate / sccm 45

[0052] Comparative Example 1

[0053] The auxiliary ion source process parameters in Example 2 were changed as shown in Table 7, while the rest remained the same as in Example 2.

[0054] Table 7. Process parameters of the auxiliary ion source in Comparative Example 1

[0055] Auxiliary source ion beam current / mA 1400 Auxiliary source oxygen flow rate / sccm 60

[0056] A peel strength of not less than 2.94 N / cm is used for a 2cm wide strip. 2 The adhesive tape was firmly attached to the surface of the film. The film on the sample surface was stretched vertically and rapidly 40 times, and the film peeled off slightly.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A 365nm ultraviolet narrowband filter for a lithography machine, comprising a glass substrate, wherein a high-reflectance film is disposed on one side of the glass substrate and an anti-reflection film is disposed on the other side, characterized in that, The high-reflectivity film layer comprises alternating layers of SiO2 and Ta2O5; The SiO2 layer and Ta2O5 layer together comprise 40-60 layers, with odd-numbered layers being Ta2O5 layers and even-numbered layers being SiO2 layers; When the lithography machine is used to prepare a 365nm ultraviolet narrowband filter, an ion sputtering coating machine is used for coating, and an auxiliary ion source is used during the deposition process. The process parameters of the auxiliary ion source are as follows: auxiliary source ion beam energy 1400-1500eV, auxiliary source ion beam current 1200-1300mA, and auxiliary source oxygen flow rate 40-50sccm. In the odd-numbered layers, the thickness of layers 1, 3, 5, 7, 9, 11, 13, and 15 is 28.72 nm, and the thickness of layers 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, and 39 is 42.94 nm. In the even-numbered layers, the thickness of layers 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, and 26 is 58.48 nm, and the thickness of layers 28, 30, 32, 34, 36, 38, and 40 is 70.13 nm. The antireflective coating consists of a Ta2O5 layer with a thickness of 30.26 nm and a SiO2 layer with a thickness of 60.82 nm.

2. The 365nm ultraviolet narrowband filter for a lithography machine according to claim 1, characterized in that, The SiO2 layer and Ta2O5 layer together comprise 40 layers.

3. A 365nm ultraviolet narrowband filter for a lithography machine according to claim 1, characterized in that, The glass substrate is Eagle XG.

4. A method for preparing a 365nm ultraviolet narrowband filter for a lithography machine as described in claim 1, characterized in that, The coating was performed using an ion sputtering coating machine, with an auxiliary ion source used during the deposition process.

5. The method for preparing a 365nm ultraviolet narrowband filter for a lithography machine according to claim 4, characterized in that, The process parameters for the ion sputtering coating machine are as follows: substrate temperature 110-120℃, substrate pressure 1.2-1.3×10⁻⁶. -4 Pa, Ta₂O₅ working pressure 1.3-1.4×10 -2 Pa, SiO2 working pressure 0.9-1.0×10 -2 Pa, sputtering source voltage 1200-1300eV, sputtering source current 700-800mA.

6. The method for preparing a 365nm ultraviolet narrowband filter for a lithography machine according to claim 4, characterized in that, The process parameters of the auxiliary ion source are as follows: auxiliary source ion beam energy 1400-1500eV, auxiliary source ion beam current 1200-1300mA, and auxiliary source oxygen flow rate 40-50sccm.

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