Polarizing beam splitter, and preparation method therefor and use thereof

Abstract

A polarizing beam splitter, and a preparation method therefor and the use thereof, wherein the polarizing beam splitter comprises a diamond substrate (1), a polarizing beam splitting film (2) and a first metallized film layer (4-1) located on a surface of one side of the diamond substrate (1), a broadband anti-reflection film (3) located on a surface of the other side of the diamond substrate (1), and a second metallized film layer (4-2) located on a side surface of the diamond substrate (1). The first metallized film layer (4-1) is located at an edge position of the surface of one side of the diamond substrate (1). When using diamond as a substrate material for the polarizing beam splitter and taking advantage of the characteristic of the high thermal conductivity of the diamond, the heat generated by the laser acting on the film layer and the substrate can be conducted away as soon as possible, thereby mitigating damage to the polarizing beam splitter caused by a local temperature rise. By means of metallizing the edges of the polarizing beam splitter, a mirror body can be integrally welded with a metal tube shell or a water-cooled structure, which provides a vacuum sealing solution with high reliability and a low leakage rate while improving the heat conduction efficiency.

Description

A polarizing beam splitter, its fabrication method and application

[0001] This application claims priority to Chinese Patent Application No. 202411514738.X, filed on October 29, 2024, entitled "A Polarizing Beam Spectroscope and Its Preparation Method and Application", the contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of polarization beam splitter technology, and in particular to a polarization beam splitter, its preparation method and application. Background Technology

[0003] Laser annealing is a process that uses a laser beam to irradiate the surface of a semiconductor, generating extremely high temperatures in the irradiated area to repair damage to the crystal and eliminate dislocations. It is an indispensable process step in the manufacturing process of very large-scale integrated circuits.

[0004] The uniformity requirements of laser annealing are extremely stringent in integrated circuit manufacturing. However, the "patterning effect" during laser annealing—where variations in light absorption caused by the device pattern lead to non-uniform temperature distribution within the chip—severely impacts device performance and yield. Research indicates that longer-wavelength infrared polarized lasers incident at a Brewster angle can significantly reduce the patterning effect in laser annealing, making related infrared laser annealing equipment a focus of attention in the domestic and international semiconductor industries.

[0005] Polarizing beam splitters, used to obtain high-performance linearly polarized light, are essential core optical components in infrared laser annealing systems. Compared to polarizing beam splitters operating in the visible and near-infrared bands, those operating in the infrared band, especially the long-wave infrared band, exhibit more pronounced thermal effects under infrared laser irradiation, resulting in a lower laser damage threshold and making it difficult to achieve high extinction ratios and high laser damage thresholds. Summary of the Invention

[0006] The purpose of this application is to provide a polarizing beam splitter and its preparation method. The polarizing beam splitter has high thermal conductivity, thereby preventing laser damage caused by temperature rise and ensuring good optical performance.

[0007] To achieve the above-mentioned objectives, this application provides the following technical solution:

[0008] This application provides a polarizing beam splitter, including a diamond substrate 1, a polarizing beam splitting film 2 and a first metallization film layer 4-1 located on one side surface of the diamond substrate 1, a broadband antireflection film 3 located on the other side surface of the diamond substrate 1, and a second metallization film layer 4-2 located on the side surface of the diamond substrate 1.

[0009] The first metallization film layer 4-1 is located at the edge of one side surface of the diamond substrate 1, and the polarizing beam splitting film 2 is located at the remaining position on one side surface of the diamond substrate 1.

[0010] Preferably, the diamond substrate 1 is double-sided polished, with an RMS value of less than 1 / 50λ for the optical surface shape and a surface roughness of less than 0.5nm.

[0011] Preferably, the surface roughness of the side of the diamond substrate 1 is less than 1.6 μm.

[0012] Preferably, an underlayer is further provided between the diamond substrate 1 and the first metallization film layer 4-1 and between the diamond substrate 1 and the second metallization film layer 4-2.

[0013] Preferably, the underlayer is a Ni-Cr alloy layer;

[0014] The molar ratio of Ni to Cr in the Ni-Cr alloy layer is 80:20.

[0015] Preferably, the materials of the first metallization layer 4-1 and the second metallization layer 4-2 are independently one or more of gold, copper, chromium and nickel.

[0016] Preferably, the thicknesses of the first metallization layer 4-1 and the second metallization layer 4-2 are independently 1.2 to 2.0 μm.

[0017] Preferably, the polarizing beam splitter 2 includes a first high refractive index material layer and a first low refractive index material layer that are stacked and cyclically arranged in sequence, and the innermost and outermost layers of the polarizing beam splitter 2 are both the first high refractive index material layers;

[0018] The refractive index of the first high-refractive-index material layer is greater than the refractive index of the first low-refractive-index material layer.

[0019] Preferably, the material of the first high refractive index material layer is ZnSe;

[0020] The first low-refractive-index material layer is made of BaF2 doped with YbF3.

[0021] Preferably, the amount of YbF3 doped in the YbF3-doped BaF2 is 0.5 wt% to 5 wt%.

[0022] Preferably, the thickness of the polarizing beam splitter 2 is 10-50 μm, and the total number of layers of the polarizing beam splitter 2 is 31.

[0023] Preferably, the broadband antireflective coating 3 includes a second high refractive index material layer and a second low refractive index material layer that are sequentially stacked and cyclically arranged, and the innermost and outermost layers of the broadband antireflective coating 3 are both the second high refractive index material layer;

[0024] The refractive index of the second high-refractive-index material layer is greater than that of the second low-refractive-index material layer.

[0025] Preferably, the material of the second high refractive index material layer is ZnSe;

[0026] The material of the second low-refractive-index material layer is BaF2 doped with YbF3.

[0027] Preferably, the amount of YbF3 doped in the YbF3-doped BaF2 is 0.5 wt% to 5 wt%.

[0028] Preferably, the thickness of the broadband antireflective coating 3 is 10-50 μm, and the total number of layers of the broadband antireflective coating 3 is 39.

[0029] This application also provides a method for preparing the polarization beam splitter described in the above technical solution, including the following steps:

[0030] After preparing a second metallization film layer 4-2 and a first metallization film layer 4-1 at the edge positions of the side surface and one side surface of the diamond substrate 1, respectively, a polarizing beam splitter 2 is prepared at the remaining position on one side surface of the diamond substrate 1, and a broadband antireflection film 3 is prepared on the other side surface of the diamond substrate 1 to obtain the polarizing beam splitter.

[0031] Preferably, when an underlayer is provided between the diamond substrate 1 and the first metallization film layer 4-1 and between the diamond substrate (1) and the second metallization film layer 4-2, the preparation method further includes preparing the underlayer by physical vapor deposition.

[0032] This application also provides the application of the polarization beam splitter described in the above technical solution or the polarization beam splitter prepared by the preparation method described in the above technical solution in the field of infrared laser annealing equipment or LPP driven laser source of EUV extreme ultraviolet lithography system in the semiconductor chip industry.

[0033] This application also provides an infrared laser annealing device, including the polarization beam splitter described in the above technical solution or the polarization beam splitter prepared by the preparation method described in the above technical solution.

[0034] This application also provides an LPP-driven laser source, including the polarization beam splitter described in the above technical solution or the polarization beam splitter prepared by the preparation method described in the above technical solution.

[0035] This application provides a polarizing beam splitter, including a diamond substrate 1, a polarizing beam splitting film 2 and a first metallization film layer 4-1 located on one side surface of the diamond substrate 1, a broadband antireflection film 3 located on the other side surface of the diamond substrate 1, and a second metallization film layer 4-2 located on the side surface of the diamond substrate 1; the first metallization film layer 4-1 is located at the edge of one side surface of the diamond substrate 1.

[0036] Compared with the prior art, the technical solution described in this application has the following beneficial effects:

[0037] 1) Diamond is used as the substrate material for the polarization beam splitter. Its high thermal conductivity can quickly conduct the heat generated by the laser acting on the film and substrate, thus mitigating the damage to the polarization beam splitter caused by local temperature rise.

[0038] 2) This application metallizes the edge of the polarizing beam splitter, which can integrally weld the mirror body with the metal shell or water-cooling structure in subsequent applications. This improves the heat conduction efficiency and provides a high-reliability and low-leakage vacuum sealing solution.

[0039] Furthermore, this application improves the optical and mechanical properties of rare earth fluorides by adjusting the materials of the polarization beam splitter and broadband antireflection film (through doping with rare earth fluorides), and uses them to replace the traditional radioactive ThF4 as a low refractive index material, which is environmentally friendly. By adjusting the total thickness of the broadband antireflection film, the surface shape change of the mirror caused by the stress of the polarization beam splitter can be further offset, maintaining the high surface shape accuracy of the polarization beam splitter. Attached Figure Description

[0040] Figure 1 is a schematic diagram of the structure of the polarizing beam splitter described in this application, wherein 1 is a diamond substrate, 2 is a polarizing beam splitter film, 3 is a broadband antireflection film, 4-1 is a first metallization film layer, and 4-2 is a second metallization film layer.

[0041] Figure 2 is a process flow diagram of the metallization film layer described in this application;

[0042] Figure 3 shows the design spectrum of the polarization beam splitter described in Example 1;

[0043] Figure 4 shows the design spectrum of the broadband antireflection membrane described in Example 1. Detailed Implementation

[0044] As shown in Figure 1, this application provides a polarizing beam splitter, including a diamond substrate 1, a polarizing beam splitting film 2 and a first metallization film layer 4-1 located on one side surface of the diamond substrate 1, a broadband antireflection film 3 located on the other side surface of the diamond substrate 1, and a second metallization film layer 4-2 located on the side surface of the diamond substrate 1.

[0045] The first metallization film layer 4-1 is located at the edge of one side surface of the diamond substrate 1.

[0046] In this application, the diamond substrate 1 is preferably double-sided polished, and the RMS value of the optical surface shape of the polished surface of the diamond substrate 1 is preferably less than 1 / 50λ; the surface roughness is preferably less than 0.5 nm. The surface roughness of the side surface of the diamond substrate 1 is preferably less than 1.6 μm. This application does not impose any special limitation on the source of the diamond substrate 1, and any source well known to those skilled in the art can be used. In the embodiments of this application, the diamond substrate 1 can be prepared by chemical vapor deposition.

[0047] In this application, the diamond substrate 1 has a diameter of 50 mm and a thickness of 2 mm.

[0048] In this application, the materials of the first metallization layer 4-1 and the second metallization layer 4-2 are preferably one or more of gold, copper, chromium, and nickel. When the materials of the first metallization layer 4-1 and the second metallization layer 4-2 are two or more of the above-mentioned specific selections, this application does not have any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this application, the materials of the first metallization layer 4-1 and the second metallization layer 4-2 are the same and can be gold.

[0049] In this application, the thicknesses of the first metallization layer 4-1 and the second metallization layer 4-2 are preferably 1.2 to 2.0 μm. In an embodiment of this application, the thicknesses of the first metallization layer 4-1 and the second metallization layer 4-2 can be 1.5 μm.

[0050] In this application, the width of the first metallization film layer 4-1 can be 2 mm.

[0051] In this application, the first metallization film layer 4-1 and the second metallization film layer 4-2 can enable the polarization beam splitter to be integrated with the metal shell or water-cooling structure in subsequent applications, thereby improving thermal conductivity and providing a high-reliability, low-leakage vacuum sealing solution.

[0052] In this application, a base layer is preferably provided between the diamond substrate 1 and the first metallization film layer 4-1 and between the diamond substrate 1 and the second metallization film layer 4-2. The base layer is preferably a Ni-Cr alloy layer (the molar ratio of Ni to Cr in the Ni-Cr alloy layer is 80:20), and the thickness of the Ni-Cr alloy layer can be 50 nm.

[0053] In this application, the center wavelength of the polarizing beam splitter 2 is preferably 11.0 μm; the polarizing beam splitter 2 uses (HL)^ 15 H is used as the initial film system, with optimized target values ​​of Rs≥99.5% and Rp≤0.1%. In this application, the polarizing beam splitter 2 preferably comprises a first high-refractive-index material layer and a first low-refractive-index material layer stacked cyclically, and the innermost and outermost layers of the polarizing beam splitter 2 are both preferably the first high-refractive-index material layer; the material of the first high-refractive-index material layer is preferably ZnSe. The material of the first low-refractive-index material layer is preferably BaF2 doped with YbF3. In this application, the doping amount of YbF3 in the YbF3-doped BaF2 is preferably 0.5wt% to 5wt%. This application does not impose any special limitation on the thickness of each layer in the polarizing beam splitter 2; thicknesses well known to those skilled in the art can be used, provided that the total thickness requirement is met and the thickness of each layer is between 10nm and 10μm. In the embodiments of this application, the doping amount of YbF3 in the YbF3-doped BaF2 can be 1.5wt%; the thickness of the polarizing beam splitter 2 can be 36μm, and the total number of layers can be 31. In the embodiments of this application, the center wavelength of the polarizing beam splitter 2 is 11.0 μm; the polarizing beam splitter 2 uses (HL)^ 15 Using H as the initial membrane system, the given optimization target values ​​are Rs≥99.5% and Rp≤0.1%.

[0054] In this application, the center wavelength of the broadband antireflection film 3 is preferably 11.0 μm; the broadband antireflection film 3 uses (HL)^ 19 H is used as the initial film system, and the optimization target value T ≥ 99.5% is given. In this application, the thickness of a single layer of the broadband antireflection film 3 is preferably ≤ 2 μm. The broadband antireflection film 3 preferably includes a second high refractive index material layer and a second low refractive index material layer stacked and cyclically arranged in sequence, and the innermost and outermost layers of the broadband antireflection film 3 are both preferably the second high refractive index material layer; the material of the second high refractive index material layer is ZnSe; the material of the second low refractive index material layer is preferably BaF2 doped with YbF3; the doping amount of YbF3 in the YbF3 doped BaF2 is preferably 0.5wt% to 5wt%. This application does not impose any special limitation on the thickness of each layer in the broadband antireflection film 3, and thicknesses well known to those skilled in the art can be used as long as the total thickness requirement is met. In the embodiments of this application, the doping amount of YbF3 in the YbF3 doped BaF2 can be 1.5wt%; the thickness of the broadband antireflection film 3 can be 30.5 μm, and the total number of layers can be 39. In the embodiments of this application, the center wavelength of the broadband antireflection film 3 can be 11.0 μm; the broadband antireflection film 3 uses (HL)^ 19H is used as the initial membrane system, and the optimization target value is given as ≥99.5%; the single-layer thickness of the broadband antireflection membrane 3 is ≤2μm.

[0055] This application also provides a method for preparing the polarization beam splitter described in the above technical solution, including the following steps:

[0056] After preparing a second metallization film layer 4-2 and a first metallization film layer 4-1 at the edge positions of the side surface and one side surface of the diamond substrate 1, respectively, a polarizing beam splitter 2 is prepared at the remaining position on one side surface of the diamond substrate 1, and a broadband antireflection film 3 is prepared on the other side surface of the diamond substrate 1 to obtain the polarizing beam splitter.

[0057] In this application, a mechanical mask or semiconductor lift-off process is preferably used to deposit a second metallization film 4-2 and a first metallization film 4-1 at the edge positions of the side surface and one side surface of the diamond substrate 1, respectively. In this application, the deposition method is preferably resistive evaporation, electron beam evaporation, or sputtering. This application does not impose any special limitations on the mechanical mask, semiconductor lift-off process, resistive evaporation, electron beam evaporation, or sputtering process; any process well known to those skilled in the art can be used. In the embodiments of this application, the process of preparing the second metallization film 4-2 and the first metallization film 4-1 can be a lift-off process, depositing the second metallization film 4-2 and the first metallization film 4-1 at the edge positions of the side surface and one side surface of the diamond substrate 1, respectively. Specifically, after uniformly coating a photoresist on one side surface of the diamond substrate, after exposure and development, the exposed and developed diamond substrate is mounted, the vacuum chamber door is closed, and a vacuum is evacuated to a background vacuum of 8.0 × 10⁻⁶. -4 Pa, the workpiece disk was rotated at 20 rpm, and the ion source was turned on to perform pre-plating bombardment cleaning of the diamond substrate for 5 minutes. The ion source was then turned off, and resistance evaporation was used to deposit metallization films on the locations of the photolithographically developed diamond substrate and on both sides of the diamond substrate. A Ni-Cr alloy film was deposited first as a base to improve the adhesion between the Au film and the diamond substrate before depositing the Au layer. The resistance evaporation source for the Ni-Cr alloy film was a spiral tungsten filament, with a deposition rate of 6.0 nm / s and a deposition thickness of 50 nm; the resistance evaporation source for the Au layer was a molybdenum boat, with a deposition rate of 5.0 nm / s and a deposition thickness of 1.5 μm. After 30 minutes of preparation, the obtained sample was removed from the vacuum chamber, and the photoresist was stripped to obtain a second metallization film 4-2 and a first metallization film 4-1 with a thickness of 1.5 μm.

[0058] In this application, a polarizing beam-splitting film 2 is prepared on the remaining position of one side surface of the diamond substrate 1. Preferably, a high-refractive-index material layer is prepared by resistance evaporation, and a low-refractive-index material layer is prepared by electron beam evaporation or resistance evaporation. This application does not impose any special limitations on the process and related conditions for preparing the high-refractive-index and low-refractive-index material layers; conditions well-known to those skilled in the art can be used. In an embodiment of this application, the preparation process of the polarizing beam-splitting film 2 can be as follows: deposition is performed by resistance evaporation. Specifically, the diamond substrate with the metallized film layer prepared is mounted, the vacuum chamber door is closed, and vacuuming is initiated until the background vacuum reaches 1.0 × 10⁻⁶. -3 Pa, start the workpiece disk rotation at 10 rpm, start the substrate baking heating at 160℃ for 120 min, adjust the workpiece disk rotation to 20 rpm, turn on the ion source to bombard and clean the diamond substrate for 5 min before plating, turn off the ion source, and start the deposition of ZnSe and YbF3-doped BaF2. Both materials are deposited using a multi-position rotating resistance evaporation source at deposition rates of 4.0 nm / s and 5.0 nm / s, respectively. Complete the preparation of polarization beam splitting film 2 according to the film system structure shown in Table 1. After preparation, allow it to cool naturally to below 80℃ and then remove it from the vacuum chamber.

[0059] In this application, the broadband antireflective coating 3 is preferably prepared on the other side surface of the diamond substrate 1 by resistive evaporation to prepare a high-refractive-index material layer and by electron beam evaporation or resistive evaporation to prepare a low-refractive-index material layer. This application does not impose any special limitations on the process and related conditions for preparing the high-refractive-index and low-refractive-index material layers; conditions well-known to those skilled in the art can be used. In an embodiment of this application, the preparation process of the broadband antireflective coating 3 can be as follows: deposition is performed by resistive evaporation, specifically: the diamond substrate obtained after the metallization film and polarization beam splitting film preparation are mounted, the vacuum chamber door is closed, and vacuuming is initiated until the background vacuum reaches 1.0 × 10⁻⁶. -3 Pa, start the workpiece disk rotation at 10 rpm, start the substrate baking heating at 160℃ for 120 min, adjust the workpiece disk rotation to 20 rpm, turn on the ion source to bombard and clean the diamond substrate for 5 min before plating, turn off the ion source, and start the deposition of ZnSe and YbF3-doped BaF2. Both materials are deposited using a multi-position rotating resistance evaporation source at deposition rates of 4.0 nm / s and 5.0 nm / s, respectively. Complete the preparation of broadband antireflection film 3 according to the film structure shown in Table 2. After preparation, allow it to cool naturally to below 80℃ and then remove it from the vacuum chamber.

[0060] This application also provides the application of the polarization beam splitter described in the above-described technical solutions or the polarization beam splitter prepared by the above-described preparation methods in the field of infrared laser annealing devices or LPP-driven laser sources for EUV extreme ultraviolet lithography systems in the semiconductor chip industry. This application does not impose any special limitations on the methods used for these applications; any methods well-known to those skilled in the art can be employed.

[0061] The following detailed description of the polarizing beam splitter, its preparation method, and its application provided in this application, with reference to specific embodiments, should not be construed as limiting the scope of protection of this application.

[0062] Example 1

[0063] Using a double-sided polished CVD diamond substrate with a diameter of 50 mm and a thickness of 2 mm, a metallization film (1.5 μm thick, with a width of 2 mm at the edge of one side of the diamond substrate) was prepared using a lift-off process. The specific preparation process (as shown in Figure 2, using 99.99% pure Au as the metallization film material) was as follows: a 5 μm thick photoresist was uniformly coated onto one side of the diamond substrate. Exposure and development were performed to expose the deposition area of ​​the metallization film. After exposure and development, the size of the photoresist-coated area was Φ. To ensure the beam splitter has sufficient aperture, the metallized film is prepared by resistance evaporation. The exposed and developed diamond substrate is then mounted, the vacuum chamber door is closed, and evacuation begins until the background vacuum reaches 8.0 × 10⁻⁶. -4 Pa, the workpiece disk was turned on and rotated at a speed of 20 r / min. The ion source was turned on to perform pre-plating bombardment cleaning of the diamond substrate for 5 min. The ion source was turned off and the deposition of the metallization film began. A Ni-Cr alloy layer was used as a base layer to improve the adhesion between the Au film layer and the diamond substrate. The Ni-Cr alloy film used a spiral tungsten wire as a resistive evaporation source with a deposition rate of 6.0 nm / s and a thickness of 50 nm. The Au film layer used a molybdenum boat as an evaporation source with a deposition rate of 5.0 nm / s and a deposition thickness of 1.5 μm. After 30 min of preparation, the obtained sample was taken out of the vacuum chamber and the photoresist was peeled off to obtain a second metallization film layer 4-2 and a first metallization film layer 4-1 with a thickness of 1.5 μm.

[0064] The polarization-splitting film was deposited using resistive evaporation. The specific process involved mounting the diamond substrate (after metallization film preparation) onto a vacuum chamber, closing the vacuum chamber door, and evacuating until the background vacuum reached 1.0 × 10⁻⁶. -3Pa, start the workpiece disk rotation at 10 rpm, start the substrate baking heating at 160℃ for 120 min, adjust the workpiece disk rotation to 20 rpm, turn on the ion source to bombard and clean the diamond substrate for 5 min before plating, turn off the ion source, and start the deposition of ZnSe and YbF3-doped BaF2. Both materials are deposited using a multi-position rotating resistance evaporation source at deposition rates of 4.0 nm / s and 5.0 nm / s, respectively. Complete the preparation of polarization beam splitting film 2 according to the film system structure shown in Table 1. After preparation, allow it to cool naturally to below 80℃ and then remove it from the vacuum chamber. The first high-refractive-index material layer in the polarizing beam splitter is made of ZnSe, and the first low-refractive-index material layer is made of YbF3-doped BaF2, with a YbF3 doping amount of 1.5 wt% in the YbF3-doped BaF2; the thickness is 36 μm, and the total number of layers is 31. Figure 3 shows the design spectrum of the polarizing beam splitter 2. As can be seen from Figure 3, the polarizing beam splitter has Rs greater than 99% and Rp less than 0.1%.

[0065] Table 1. Materials and thicknesses of each layer of the polarization beam splitter film.

[0066] The broadband antireflection coating is deposited using resistive evaporation. The specific process involves: mounting the diamond substrate (after metallization and polarization separation film preparation) onto a vacuum chamber; closing the vacuum chamber door; and evacuating until the background vacuum reaches 1.0 × 10⁻⁶. -3 Pa, start the workpiece disk rotation at 10 rpm, start the substrate baking heating at 160℃ for 120 min, adjust the workpiece disk rotation to 20 rpm, turn on the ion source to bombard and clean the diamond substrate for 5 min before plating, turn off the ion source, and start the deposition of ZnSe and YbF3-doped BaF2. Both materials are deposited using a multi-position rotating resistance evaporation source at deposition rates of 4.0 nm / s and 5.0 nm / s, respectively. Complete the preparation of broadband antireflection film 3 according to the film structure shown in Table 2. After preparation, allow it to cool naturally to below 80℃, remove it from the vacuum chamber, and complete the preparation of the entire polarization beam splitter. The second high-refractive-index material layer in the broadband antireflective coating 3 is made of ZnSe, and the second low-refractive-index material layer is made of YbF3-doped BaF2, with the YbF3 doping amount in the YbF3-doped BaF2 being 1.5 wt%. The thickness of the broadband antireflective coating 3 is 30.5 μm, and the total number of layers is 39. The thickness of a single layer of the broadband antireflective coating 3 is ≤2 μm. Figure 4 shows the design spectrum of the broadband antireflective coating 3. As can be seen from Figure 4, the transmittance of the broadband antireflective coating 3 is greater than 99.5%.

[0067] Table 2. Materials and thicknesses of each layer of the broadband antireflective coating.

[0068] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A polarizing beam splitter, characterized in that, It includes a diamond substrate (1), a polarizing beam splitting film (2) and a first metallization film layer (4-1) located on one side surface of the diamond substrate (1), a broadband antireflection film (3) located on the other side surface of the diamond substrate (1), and a second metallization film layer (4-2) located on the side surface of the diamond substrate (1); The first metallization film layer (4-1) is located at the edge of one side surface of the diamond substrate (1), and the polarizing beam splitting film (2) is located at the remaining position on one side surface of the diamond substrate (1).

2. The polarizing beam splitter as described in claim 1, characterized in that, The diamond substrate (1) is double-sided polished, with an RMS value of less than 1 / 50λ for optical surface shape and a surface roughness of less than 0.5nm.

3. The polarizing beam splitter as described in claim 2, characterized in that, The surface roughness of the side of the diamond substrate (1) is less than 1.6 μm.

4. The polarizing beam splitter as described in claim 1, characterized in that, An underlayer is also provided between the diamond substrate (1) and the first metallization film layer (4-1) and between the diamond substrate (1) and the second metallization film layer (4-2).

5. The polarizing beam splitter as described in claim 4, characterized in that, The underlayer is a Ni-Cr alloy layer; The molar ratio of Ni to Cr in the Ni-Cr alloy layer is 80:

20.

6. The polarizing beam splitter as described in claim 1, characterized in that, The materials of the first metallization layer (4-1) and the second metallization layer (4-2) are independently one or more of gold, copper, chromium and nickel.

7. The polarizing beam splitter as described in claim 6, characterized in that, The thicknesses of the first metallization layer (4-1) and the second metallization layer (4-2) are independently 1.2 to 2.0 μm.

8. The polarizing beam splitter as described in claim 1, characterized in that, The polarizing beam splitter (2) includes a first high refractive index material layer and a first low refractive index material layer stacked in sequence and cyclically arranged, and the innermost and outermost layers of the polarizing beam splitter (2) are both the first high refractive index material layers; The refractive index of the first high-refractive-index material layer is greater than the refractive index of the first low-refractive-index material layer.

9. The polarizing beam splitter as described in claim 8, characterized in that, The material of the first high refractive index material layer is ZnSe; The first low-refractive-index material layer is made of BaF2 doped with YbF3.

10. The polarizing beam splitter as described in claim 9, characterized in that, The doping amount of YbF3 in the YbF3-doped BaF2 is 0.5wt% to 5wt%.

11. The polarizing beam splitter according to any one of claims 8 to 10, characterized in that, The polarizing beam splitter (2) has a thickness of 10-50 μm and a total of 31 layers.

12. The polarizing beam splitter as described in claim 1, characterized in that, The broadband antireflective coating (3) includes a second high refractive index material layer and a second low refractive index material layer stacked in sequence and cyclically arranged, and the innermost and outermost layers of the broadband antireflective coating (3) are both the second high refractive index material layer; The refractive index of the second high-refractive-index material layer is greater than that of the second low-refractive-index material layer.

13. The polarizing beam splitter as described in claim 12, characterized in that, The material of the second high refractive index material layer is ZnSe; The material of the second low-refractive-index material layer is BaF2 doped with YbF3.

14. The polarizing beam splitter as described in claim 13, characterized in that, The doping amount of YbF3 in the YbF3-doped BaF2 is 0.5wt% to 5wt%.

15. The polarizing beam splitter according to any one of claims 12 to 14, characterized in that, The thickness of the broadband antireflective coating (3) is 10-50 μm, and the total number of layers of the broadband antireflective coating (3) is 39.

16. The method for preparing the polarizing beam splitter according to any one of claims 1 to 3 or any one of claims 6 to 15, characterized in that, Includes the following steps: After preparing a second metallization film layer (4-2) and a first metallization film layer (4-1) at the edge positions of the side surface and one side surface of the diamond substrate (1), respectively, a polarizing beam splitter film (2) is prepared at the remaining position of one side surface of the diamond substrate (1), and a broadband antireflection film (3) is prepared on the other side surface of the diamond substrate (1) to obtain the polarizing beam splitter.

17. The preparation method according to claim 16, characterized in that, When an underlayer is provided between the diamond substrate (1) and the first metallization film layer (4-1) and between the diamond substrate (1) and the second metallization film layer (4-2), the preparation method further includes preparing the underlayer by physical vapor deposition.

18. The application of the polarizing beam splitter according to any one of claims 1 to 15 or the polarizing beam splitter prepared by the preparation method according to claim 16 or 17 in the field of infrared laser annealing equipment or LPP driven laser source for EUV extreme ultraviolet lithography system in the semiconductor chip industry.

19. An infrared laser annealing apparatus, characterized in that, The polarizing beam splitter described in any one of claims 1 to 15 or the polarizing beam splitter prepared by the preparation method described in claim 16 or 17.

20. An LPP-driven laser source, characterized in that, The polarizing beam splitter described in any one of claims 1 to 15 or the polarizing beam splitter prepared by the preparation method described in claim 16 or 17.

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