A filter membrane stripping die based on a BaO sacrifice layer and a preparation method and a stripping method thereof

Abstract

The application provides a filter film stripping mold based on a BaO sacrificial layer and a preparation method and a stripping method thereof, and belongs to the technical field of optical elements and film preparation. The BaO is used as the sacrificial layer, can be removed by dissolving in water, does not introduce other etching liquids such as acids, alkalis and organic solvents, does not have a chemical reaction with a target filter film in a dissolving process, and further prevents the target filter film from being torn, wrinkled or damaged. The BaO sacrificial layer is deposited by sputtering, the uniformity and roughness of the target filter film are consistent, compared with the traditional method of evaporating and coating NaCl outside a vacuum chamber, the roughness and uniformity are improved, and a filter film with lower scattering rate can be prepared.

Description

Technical Field

[0001] This invention belongs to the field of optical element and thin film preparation technology, specifically relating to a filter removal mold based on a BaO sacrificial layer, its preparation method, and removal method. Background Technology

[0002] When optical filters are used in extreme ultraviolet (EUV) and soft X-ray bands, the materials must not only possess matching optical constants such as refractive index and extinction coefficient, but also have sufficient intrinsic mechanical strength and toughness. While commonly used high atomic number metal materials (such as Al, Zr, Mo, and Ru) have excellent optical properties, they generally suffer from high intrinsic brittleness. At the same time, intrinsically suitable materials that meet low stress requirements are relatively scarce, and many materials with excellent optical properties are difficult to self-support due to excessively high intrinsic stress in their single-layer films.

[0003] Without the support and constraint of a rigid substrate, even minute internal stresses can cause wrinkling, curling, or cracking of self-supporting films. This is mainly because the stress in self-supporting films originates from intrinsic stresses related to the mobility of deposited atoms and lattice defects, as well as thermal stresses generated by the mismatch in thermal expansion coefficients between the film and the substrate. Furthermore, during the detachment of the self-supporting film from the substrate, the complete release of thermal stress, combined with residual intrinsic stress, can easily lead to catastrophic failure, resulting in film tearing, wrinkling, or breakage. Current self-supporting film fabrication processes often employ mechanical peeling or chemical etching of the sacrificial layer to achieve film removal. However, during chemical etching, changes in the surface tension of the etching solution and the chemical reaction can easily cause film tearing, wrinkling, or breakage. Summary of the Invention

[0004] The purpose of this invention is to provide a filter film removal mold based on a BaO sacrificial layer, its preparation method, and the removal method. This invention uses BaO as a sacrificial layer, which can be dissolved in water for removal to achieve film removal, and can prevent the film from being affected by chemical solutions, resulting in tearing, wrinkling, pitting, or damage.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: A filter membrane removal mold based on a BaO sacrificial layer includes a substrate and a BaO sacrificial layer disposed on the surface of the substrate; The roughness of the BaO sacrificial layer is Ra 0.1~10nm.

[0006] Preferably, the thickness of the BaO sacrificial layer is 20~500nm.

[0007] Preferably, the substrate is a non-porous substrate or a porous substrate with a thickness of 0.1~100mm; the roughness of the substrate is 0.1~5nm, and the peak-to-valley value is ≤1 / 10λ; The porosity of the porous substrate is 3-60%.

[0008] The present invention also provides a method for preparing the filter sheet demolding mold described in the above technical solution, comprising the following steps: A BaO sacrificial layer is sputtered onto the substrate surface using a BaO target to obtain the filter release mold based on the BaO sacrificial layer.

[0009] Preferably, the sputtering parameters include: working gas pressure of 0.1~50 Pa, sputtering power of 10~2000 W, substrate bias of -20~100 V, sputtering gas of Ar, and vacuum degree <5.0×10⁻⁶. -5 Pa, substrate temperature is 20~100℃, target-substrate distance is 1~1000mm.

[0010] The present invention also provides a filter removal method based on a BaO sacrificial layer, comprising the following steps: A target filter membrane layer is prepared on the surface of the BaO sacrificial layer of the filter membrane release mold described in the above technical solution; The BaO sacrificial layer is dissolved in deionized water to remove the target filter membrane layer, thus obtaining the target filter.

[0011] Preferably, the target filter is made of one or more elements and compounds of Mg, Al, Si, Zn, Zr, Ru, In, Be, B, C, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Se, Sr, Y, Nb, Mo, Rh, Pd, Ag, Sn, Te, Ha, Ta, W, Ir, Pt, Au, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb; Or one or more of the following compounds containing the elements Li, N, O, F, Na, P, Cl, K, Ca, As, Br, Rb, I, Cs and Ca.

[0012] Preferably, the target filter has a light transmission aperture ≥ 5 mm and a thickness of 10~300 nm.

[0013] Preferably, the dissolution temperature is 0~100℃ and the time is 1~300min.

[0014] This invention provides a filter removal mold based on a BaO sacrificial layer, comprising a substrate and a BaO sacrificial layer disposed on the surface of the substrate; the roughness of the BaO sacrificial layer is Ra 0.1~10nm. This invention uses BaO as the sacrificial layer, which can be dissolved in water for removal without introducing other etching solutions such as acids, alkalis, or organic solvents. During the dissolution process, it does not chemically react with the target filter, thereby preventing the target filter from tearing, pitting, wrinkling, or breaking.

[0015] Furthermore, this invention prepares a BaO sacrificial layer via sputtering deposition, achieving consistent uniformity and roughness with the target filter. Compared to the traditional method of pre-evaporating and depositing NaCl outside the vacuum chamber, both roughness and uniformity are improved, allowing for the preparation of filters with lower scattering. Moreover, the BaO sacrificial layer can be continuously deposited with the target filter within the same vacuum chamber (equipped with multiple cathodes and targets), avoiding contamination, damage, vacuum breaches, or stress changes due to atmospheric exposure during transfer / exposure, thus enabling better stress control of the film. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a microscope image of the BaO sacrificial layer obtained by sputtering deposition in Example 1 of the present invention; Figure 2 This is a microscope image of the target metal filter obtained by demolding in Example 1; Figure 3 Microscopic image of the NaCl vapor-deposited layer obtained in Comparative Example 1; Figure 4 This is a photograph of the NaCl vapor-deposited layer obtained in Comparative Example 1. Figure 5 and Figure 6 This is a microscope image of the target metal filter obtained after descaling in Comparative Example 1. Detailed Implementation

[0018] This invention provides a filter removal mold based on a BaO sacrificial layer, comprising a substrate and a BaO sacrificial layer disposed on the surface of the substrate; The roughness of the BaO sacrificial layer is Ra 0.1~10nm.

[0019] Unless otherwise specified, all raw materials used in this invention are commercially available products well known to those skilled in the art.

[0020] In this invention, the roughness of the BaO sacrificial layer is Ra 0.1~10nm, and in specific embodiments it can be 0.5, 1.0, 2.0, 3.0 or 5.0nm; the thickness of the BaO sacrificial layer is 20~500nm, and in specific embodiments it can be 25, 30, 40, 55, 60, 100, 150 or 250nm. The BaO material used as the sacrificial layer in this invention is readily soluble in water, and does not produce a large amount of gaseous byproducts during dissolution (compared to barium carbonate). On the one hand, BaO as a sacrificial layer does not introduce additional acid or alkali effects during dissolution and demolding; on the other hand, it does not produce a large number of bubbles that could damage the filter during demolding (compared to the hydrogen gas produced during acid etching of metals). It is suitable for all types of filters on the market, especially for metal filters made of Al, Mg, and Fe, which are relatively reactive and easily react with acids and alkalis.

[0021] In this invention, the substrate is a non-porous substrate or a porous substrate, and in a specific embodiment, it can be a porous substrate; the porosity of the porous substrate is 3~60%; the thickness of the substrate is 0.1~100mm, and in a specific embodiment, it can be 0.3, 5, 10, 20, 35 or 60nm; the roughness of the substrate is 0.1~5nm, and in a specific embodiment, it can be 0.3, 0.5, 1.0, 1.5, 2.0 or 3.0nm, with a peak-to-valley value ≤1 / 10λ; the material of the substrate can be single-crystal silicon (Si), quartz or glass, and in a specific embodiment, it can be a JGS1 quartz substrate, a ULE glass substrate or a K9 glass substrate.

[0022] The present invention does not have any particular limitation on the preparation method of porous substrates. In specific embodiments, it can be prepared by conventional methods such as laser ablation, electrochemical etching, cold working and drilling.

[0023] The present invention also provides a method for preparing the filter sheet demolding mold described in the above technical solution, comprising the following steps: A BaO sacrificial layer is sputtered onto the substrate surface using a BaO target to obtain the filter release mold based on the BaO sacrificial layer.

[0024] In this invention, the sputtering parameters include: a working gas pressure of 0.1~50 Pa, which in specific embodiments can be 0.5, 1.0, 5.0, 10, 25, 30, or 40 Pa; a sputtering power of 10~2000 W, which in specific embodiments can be 100, 300, 500, 800, 1000, or 1600 W; a substrate bias of -20~100 V, which in specific embodiments can be -10, 10, 30, or 50; and the sputtering gas is Ar gas with a vacuum degree <5.0 × 10⁻⁶. -5The substrate temperature is 20~100℃, and in specific embodiments it can be 35 or 40℃; the target-substrate distance is 1~100mm, and in specific embodiments it can be 5, 10, 20 or 500mm. This invention achieves consistent uniformity and roughness of the target filter through sputtering deposition of an inorganic sacrificial layer. Compared with the traditional method of pre-evaporating and depositing NaCl outside the vacuum chamber, both roughness and uniformity are improved, allowing for the preparation of filters with lower scattering rates. Furthermore, the inorganic sacrificial layer can be continuously deposited with the target filter in the same vacuum chamber (equipped with multiple cathodes and targets), avoiding contamination, deliquescence, damage, stress changes due to vacuum breaking or temperature variations caused by transfer / exposure to the atmospheric environment, resulting in better stress control of the film.

[0025] The present invention also provides a filter removal method based on a BaO sacrificial layer, comprising the following steps: A target filter membrane layer is prepared on the surface of the BaO sacrificial layer of the filter membrane release mold described in the above technical solution; The BaO sacrificial layer is dissolved in deionized water to remove the target filter membrane layer, thus obtaining the target filter.

[0026] In this invention, the target filter is made of one or more of the following elements and their compounds: Mg, Al, Si, Zn, Zr, Ru, In, Be, B, C, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Se, Sr, Y, Nb, Mo, Rh, Pd, Ag, Sn, Te, Ha, Ta, W, Ir, Pt, Au, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb; or one or more compounds containing Li, N, O, F, Na, P, Cl, K, Ca, As, Br, Rb, I, Cs, and Ca. In specific embodiments, the material can be Al, Mg, or Fe.

[0027] In this invention, the light transmission aperture of the target filter is ≥5mm, specifically 5~25mm, and in specific embodiments it can be 8, 10, 14, 16, 20 or 24mm; the thickness is 10~300nm, and in specific embodiments it can be 30, 50, 80, 100, 150 or 230nm.

[0028] In this invention, the dissolution temperature is 0~100℃, and in specific embodiments it can be 10, 25, 30 or 50℃; the time is 1~300min, and in specific embodiments it can be 10, 30, 60 or 90min.

[0029] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the filter film removal mold based on the BaO sacrificial layer provided by the present invention, as well as its preparation and removal methods, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0030] The JGS1 quartz substrate with a thickness of 2 mm and a roughness Ra of 1 nm used in the following embodiments of the present invention.

[0031] Example 1 1) Sputter-deposited BaO sacrificial layer: After the substrate is washed and dehydrated, it is placed in the magnetron sputtering cavity and evacuated to a high vacuum environment (1~10×10⁻⁶). - 5 BaO target material was pre-sputtered in an Ar atmosphere to remove surface contaminants, followed by deposition of a BaO sacrificial layer via radio frequency magnetron sputtering; the working pressure was 0.1~1 Pa, the sputtering power was 5000 W, the substrate bias was -20 V, and the vacuum degree was <5.0×10⁻⁶ Pa. -5 Pa, substrate temperature 25℃, target-substrate distance 100~250mm, to obtain a BaO sacrificial layer with a thickness of 100nm.

[0032] 2) Prepare the target filter membrane layer on the surface of the BaO sacrificial layer: The substrate obtained in step 1) is placed in the sputtering chamber and evacuated to a high vacuum environment. The Al target is pre-sputtered under an Ar atmosphere, and then an Al filter film is deposited by DC magnetron sputtering. The sputtering gas pressure is 0.5 Pa, the sputtering power is 1000 W, the substrate temperature is 100 °C, the target grazing rate is 1~100 m / s, and the number of target grazings is 1~200 times, resulting in an Al metal thin film with a thickness of 200 nm.

[0033] 3) Dissolving the BaO sacrificial layer for demolding: After cleaning and drying, the coated sample obtained in step 2) is placed in a container. Deionized water sufficient to submerge the surface of the BaO sacrificial layer is added to the container. The mixture is stirred and circulated for 1 to 10 minutes at 25 to 40°C. The filter is then removed, cleaned with deionized water, and dried to obtain the target Al metal filter.

[0034] Comparative Example 1 1) Evaporated NaCl layer: The dried substrate was placed in a vacuum evaporation chamber and evacuated to a high vacuum environment. The NaCl raw material loaded in the hot evaporation boat was pre-degassed and heated. The evaporation source was stabilized under the condition of baffle shielding. Then, under the condition of controlled deposition rate and substrate rotation, the baffle was opened in stages to carry out hot evaporation deposition. Intermittent cooling and stress release were carried out between each deposition stage to obtain a NaCl vapor deposition layer with a thickness of 1 μm.

[0035] 2) Preparation of the target filter membrane layer on the surface of the NaCl vapor-deposited layer: The substrate obtained in step 1) is placed in the sputtering chamber and evacuated to a high vacuum environment. The Al target is pre-sputtered under an Ar gas atmosphere, and then an Al filter film is deposited by DC magnetron sputtering. The sputtering gas pressure is 0.5 Pa, the sputtering power is 1000 W, the substrate temperature is 100 °C, the target grazing rate is 1~100 m / s, and the number of target grazings is 1~200 times, resulting in an Al metal thin film with a thickness of 200 nm.

[0036] 3) Etching to remove the NaCl vapor deposit: After cleaning and drying, the coated sample obtained in step 2) is placed in a sealed etching container. Deionized water is added to the container, and the sample is allowed to stand and dissolve for 1-10 minutes at 25°C. The filter is then removed, cleaned and dried with deionized water to obtain the target metal filter.

[0037] Test case Figure 1 This is a microscope image of the BaO sacrificial layer obtained by sputtering deposition in Example 1 of the present invention; Figure 1 The results show that the BaO sacrificial layer has good roughness, good scattering rate, and no sand holes or large-sized particle protrusions.

[0038] Figure 2 This is a microscope image of the target metal filter obtained by demolding in Example 1; from Figure 2 The results show that the target metal filter surface has no undissolved BaO particles, has a metallic luster, and is free of pinholes and large particle protrusions.

[0039] Figure 3 This is a microscope image of the NaCl vapor-deposited layer obtained in Comparative Example 1; (The image is from...) Figure 3 The results show that the NaCl vapor-deposited layer has a rough surface and poor scattering rate.

[0040] Figure 4 This is a physical image of the NaCl vapor-deposited layer obtained in Comparative Example 1. Figure 4 The results show that the presence of incompletely evaporated NaCl crystal particles in the NaCl vapor deposition layer can lead to film damage and pinholes.

[0041] Figure 5 and Figure 6 This is a microscope image of the target metal filter obtained after demolding in Comparative Example 1. Figures 5-6 The results showed that the surface of the obtained metal filter contained incompletely dissolved NaCl particles of different colors.

[0042] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A filter film removal mold based on a BaO sacrificial layer, comprising a substrate and a BaO sacrificial layer disposed on the surface of the substrate; The roughness of the BaO sacrificial layer is Ra 0.1~10nm.

2. The filter sheet demolding mold according to claim 1, characterized in that, The thickness of the BaO sacrificial layer is 20~500nm.

3. The filter sheet demolding mold according to claim 1, characterized in that, The substrate is a non-porous substrate or a porous substrate with a thickness of 0.1~100mm; the roughness of the substrate is 0.1~5nm, and the peak-to-valley value is ≤1 / 10λ. The porosity of the porous substrate is 3-60%.

4. The method for preparing the filter sheet demolding mold according to any one of claims 1 to 3, characterized in that, Includes the following steps: A BaO sacrificial layer is sputtered onto the substrate surface using a BaO target to obtain the filter release mold based on the BaO sacrificial layer.

5. The preparation method according to claim 4, characterized in that, The sputtering parameters include: working gas pressure of 0.1~50 Pa, sputtering power of 10~2000 W, substrate bias of -20~100 V, sputtering gas of Ar, and vacuum degree <5.0×10⁻⁶. -5 Pa, substrate temperature is 20~100℃, target-substrate distance is 1~1000mm.

6. A method for removing filter membranes based on a BaO sacrificial layer, characterized in that, Includes the following steps: A target filter membrane layer is prepared on the surface of the BaO sacrificial layer of the filter membrane release mold according to any one of claims 1 to 3; The BaO sacrificial layer is dissolved in deionized water to remove the target filter membrane layer, thus obtaining the target filter.

7. The filter sheet removal method according to claim 6, characterized in that, The target filter is made of one or more of the following elements and compounds: Mg, Al, Si, Zn, Zr, Ru, In, Be, B, C, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ge, Se, Sr, Y, Nb, Mo, Rh, Pd, Ag, Sn, Te, Ha, Ta, W, Ir, Pt, Au, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. Or one or more of the following compounds containing the elements Li, N, O, F, Na, P, Cl, K, Ca, As, Br, Rb, I, Cs and Ca.

8. The filter sheet removal method according to claim 6, characterized in that, The target filter has a light transmission aperture of ≥5mm and a thickness of 10~300nm.

9. The filter sheet removal method according to claim 6, characterized in that, The dissolution temperature is 0~100℃, and the time is 1~300min.

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