A filter membrane stripping die based on a high polymer sacrificial layer and a preparation method and a stripping method thereof

Abstract

The application provides a filter film stripping mold based on a high polymer sacrificial layer and a preparation method and a stripping method thereof, and belongs to the technical field of optical elements and film preparation. The high polymer is used as the sacrificial layer, the high polymer can be removed by being dissolved in an organic solvent, other etching liquid such as acid and alkali is not introduced for etching removal, no chemical reaction with the target filter film occurs in the dissolving process, and then the target filter film can be prevented from being torn, wrinkled or damaged. And the dissolving rate of the high polymer sacrificial layer is more than 10 times faster than that of a metal sacrificial layer, a NaCl evaporation layer and a BaO sacrificial layer, the high polymer sacrificial layer can be quickly dissolved to the center of the high polymer sacrificial layer when a large-size filter film is prepared, and the target filter film can be further prevented from being torn, wrinkled or damaged, and the stripping efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of optical element and thin film preparation technology, specifically relating to a filter stripping mold based on a polymer sacrificial layer, its preparation method, and stripping 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 metals (such as Zr, Mo, and Ru) exhibit excellent optical properties, they generally suffer from significant intrinsic brittleness. Furthermore, intrinsically suitable materials that meet low stress requirements are relatively scarce, and many materials with excellent optical properties struggle to achieve self-support due to excessively high intrinsic stress in their monolayer 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 polymer sacrificial layer, as well as its preparation method and removal method. The polymer sacrificial layer provided by this invention can be dissolved in an organic solvent for removal to achieve film removal, and can prevent the film from tearing, wrinkling or breaking.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: A filter membrane release mold based on a polymer sacrificial layer includes a substrate and a polymer sacrificial layer disposed on the surface of the substrate. The polymer sacrificial layer is polymethyl methacrylate and / or polystyrene; the roughness of the polymer sacrificial layer is Ra 1~100nm.

[0006] Preferably, the thickness of the polymer sacrificial layer is 10~500 nm.

[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 polymer solution is formed on the substrate surface to form a film, which is then cured to obtain the filter release mold based on the polymer sacrificial layer.

[0009] Preferably, the concentration of the polymer solution is 0.01~10wt%.

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

[0011] Preferably, the good solvent for the polymer sacrificial layer includes acetone or N-methylpyrrolidone.

[0012] 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.

[0013] Preferably, the target filter has a light transmission aperture ≥ 5 mm and a thickness of 10~300 nm.

[0014] Preferably, the dissolution temperature is 0~70℃ and the time is 1~15min.

[0015] This invention provides a filter removal mold based on a polymer sacrificial layer, comprising a substrate and a polymer sacrificial layer disposed on the surface of the substrate; the polymer sacrificial layer is polymethyl methacrylate and / or polystyrene; the roughness of the polymer sacrificial layer is Ra 1~100 nm. This invention uses a polymer as the sacrificial layer, which can be dissolved in organic solvents for removal without introducing other acidic or alkaline etching solutions. During dissolution, it does not chemically react with the target filter, thus preventing the target filter from being corroded, torn, wrinkled, or damaged by other acidic or alkaline etchants. Furthermore, the dissolution rate of the polymer sacrificial layer is more than 10 times faster than that of metal sacrificial layers, NaCl vapor-deposited layers, and BaO sacrificial layers. During the preparation of large-size filters, it can quickly dissolve to the center of the polymer sacrificial layer, further preventing tearing, wrinkling, or damage to the target filter and improving removal efficiency.

[0016] Furthermore, the present invention prepares the polymer sacrificial layer by coating, which eliminates the need for sputtering coating and avoids the stress generated during sputtering coating. This further prevents the risk of the target filter being torn, wrinkled or damaged due to stress during the subsequent demolding process. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a microscope image of the target metal filter obtained by demolding in Example 1; Figure 2 The graph shows the transmittance of the target metal filter obtained by defilming in Example 1 and Comparative Example 1, where the vertical axis represents transmittance (%) and the horizontal axis represents wavelength (nm). Figure 3 The image shows an optical microscope image of the target metal filter and the NaCl vapor-deposited layer obtained by demolding in Comparative Example 1, with the metal filter on the left and the NaCl vapor-deposited layer on the right. Figure 4 The images show actual photos of the target filters obtained in Example 1 and Comparative Example 1, with the upper part representing Example 1 and the lower part representing Comparative Example 1. Figure 5 The images show actual photos of the target filters obtained in Example 1 and Comparative Example 1; the left side is Comparative Example 1, and the right side is Example 1. Detailed Implementation

[0019] This invention provides a filter membrane removal mold based on a polymer sacrificial layer, comprising a substrate and a polymer sacrificial layer disposed on the surface of the substrate; The polymer sacrificial layer is polymethyl methacrylate and / or polystyrene; the roughness of the polymer sacrificial layer is Ra 1~100nm.

[0020] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0021] In this invention, the weight-average molecular weight of the polymer can be 300,000 to 950,000 g / mol.

[0022] In this invention, the roughness of the polymer sacrificial layer is Ra 1~100nm, and in specific embodiments it can be 2, 5, 10, 15, 20, 35 or 60nm; the thickness of the polymer sacrificial layer is 10~500nm, and in specific embodiments it can be 30, 50, 100, 150 or 350nm.

[0023] 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.

[0024] 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.

[0025] 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 polymer solution is formed on the substrate surface to form a film, which is then cured to obtain the filter release mold based on the polymer sacrificial layer.

[0026] In this invention, the concentration of the polymer solution is 0.01~10wt%, and in specific embodiments it can be 0.1wt%, 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 3.0wt% or 5.0wt%.

[0027] In this invention, the method for preparing the polymer solution includes the following steps: A polymer solution is obtained by mixing a polymer and an organic solvent, followed by microfiltration to remove insoluble or undissolved polymers. The organic solvent can be toluene or anisole. The microfiltration instrument is a polytetrafluoroethylene filter with a pore size of 0.22 μm. The mixing can be done by magnetic stirring, heating and stirring, or static dissolution.

[0028] In this invention, the coating method is spin coating or blade coating. This invention does not have any special limitations on the conditions for spin coating or blade coating, and any method known to those skilled in the art can be used.

[0029] In this invention, the curing is either thermal curing or UV curing; the thermal curing temperature is 80~120℃, and the time is 30~1000s; the UV curing wavelength is 200~400nm, and the irradiation energy is 50~5000mJ / cm². 2 The irradiation time is 1 second to 10 minutes.

[0030] The present invention also provides a filter removal method based on a polymer sacrificial layer, comprising the following steps: A target filter membrane layer is prepared on the surface of the polymer sacrificial layer of the filter membrane release mold described in the above technical solution; The polymer sacrificial layer is dissolved using a good solvent to remove the target filter membrane, thus obtaining the target filter.

[0031] In this invention, the good solvent for the polymer sacrificial layer includes acetone or N-methylpyrrolidone, and in a specific embodiment it can be N-methylpyrrolidone.

[0032] In this invention, the material of the target filter is one or more of the elemental substances 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 compounds containing Li, N, O, F, Na, P, Cl, K, Ca, As, Br, Rb, I, Cs and Ca. In specific embodiments, it can be Al, Mg, Fe, In, Zr, ZrSi2 or Zn.

[0033] 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.

[0034] In this invention, the dissolution temperature is 0~70℃, and in specific embodiments it can be 10, 25, 30 or 50℃; the time is 1~15min, and in specific embodiments it can be 3, 5, 6, 10, 12 or 13min.

[0035] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, describes the filter membrane removal mold based on the polymer sacrificial layer provided by the present invention, as well as its preparation and removal methods. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0036] 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.

[0037] Example 1 1) Preparation of PMMA sacrificial layer by coating: PMMA particles with a molecular weight of 950,000 g / mol were dissolved in anisole and magnetically stirred to obtain a 4 wt% PMMA solution. The solution was filtered through a 0.22 μm PTFE membrane to remove incompletely dissolved particles, resulting in a clear liquid. The substrate was cleaned and dried before being placed on a spin coater. The PMMA solution was dropped onto the substrate surface, and spin-coating was performed sequentially at 200 rpm for 30 s and 1000 rpm for 1–10 min. The solution was then cured at 120 °C for 5–30 min to obtain a 200 nm thick PMMA sacrificial layer with a roughness Ra of 20 nm.

[0038] 2) Prepare the target filter membrane layer on the surface of the PMMA sacrificial layer: Place the substrate obtained in step 1) in the sputtering chamber and evacuate to a high vacuum environment (1~10×10⁻⁶). -5 Al target material was pre-sputtered in an Ar atmosphere, and then an Al filter film was deposited by DC magnetron sputtering. The sputtering gas pressure was 0.5 Pa, the sputtering power was 1000 W, the substrate temperature was 100 °C, the target grazing rate was 1~100 m / s, and the number of target grazings was 1~200 times, resulting in an Al metal thin film with a thickness of 200 nm.

[0039] 3) Demolding the PMMA sacrificial layer using a good solvent: Place the coated sample obtained in step 2) into a container, add 50 mL of acetone to the container, stir and dissolve at 25~40℃ for 1~10 min, take out the filter, wash and dry with deionized water to obtain the target Al metal filter.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Test case Figure 1 This is a microscope image of the target metal filter obtained by demolding in Example 1; from Figure 1 The results show that there is no organic sacrificial layer residue on the surface of the target metal filter, and it exhibits a metallic luster, good gloss, and no pinholes.

[0044] Figure 2 This is a transmittance graph of the target metal filter obtained by defilming in Example 1 and Comparative Example 1, where the vertical axis represents transmittance (%) and the horizontal axis represents wavelength (nm). Note: Figure 2 The orange curve represents a parallel experiment of NaCl vapor deposition. (From...) Figure 2 The results show that the transmittance of the metal filter obtained in Example 1 is consistently above 45%, which is an improvement compared to the 40% transmittance of the NaCl layer deposited in Comparative Example 1.

[0045] Figure 3The images show optical microscope images of the target metal filter and the NaCl vapor-deposited layer obtained from the demolding process in Comparative Example 1, with the metal filter on the left and the NaCl vapor-deposited layer on the right. Figure 3 The results show that the surface of the NaCl vapor-deposited layer is rough, and the surface of the metal filter obtained by removing the NaCl vapor-deposited layer is also rough and contaminated with NaCl.

[0046] Figure 4 These are physical images of the target filters obtained in Example 1 and Comparative Example 1, with the upper part representing Example 1 and the lower part representing Comparative Example 1; Figure 4 The results show that the filter sheet of Example 1, which was delaminated using an organic sacrificial layer substrate, has a metallic luster, a mirror finish, and high reflectivity; while the filter sheet of Comparative Example 1, which was delaminated using a NaCl vapor-deposited layer substrate, is whitish, not mirror-like, and has poor reflectivity.

[0047] Figure 5 These are physical images of the target filters obtained in Example 1 and Comparative Example 1; the left side is Comparative Example 1, and the right side is Example 1; Figure 5 The results show that the target filter in Example 1, which was delaminated using a sputtered PMMA sacrificial layer, had no pinholes; while the target filter in Comparative Example 1, which was delaminated using a NaCl vapor deposition layer, had severe pinholes.

[0048] 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 membrane release mold based on a polymer sacrificial layer, comprising a substrate and a polymer sacrificial layer disposed on the surface of the substrate; The polymer sacrificial layer is polymethyl methacrylate and / or polystyrene; the roughness of the polymer sacrificial layer is Ra 1~100nm.

2. The filter sheet demolding mold according to claim 1, characterized in that, The thickness of the polymer sacrificial layer is 10~500nm.

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 polymer solution is formed on the substrate surface to form a film, which is then cured to obtain the filter release mold based on the polymer sacrificial layer.

5. The preparation method according to claim 4, characterized in that, The concentration of the polymer solution is 0.01~10wt%.

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

7. The filter sheet removal method according to claim 6, characterized in that, Good solvents for the polymer sacrificial layer include acetone or N-methylpyrrolidone.

8. 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.

9. 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.

10. The filter sheet removal method according to claim 6, characterized in that, The dissolution temperature is 0~70℃, and the time is 1~15min.

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