Polarizing beam splitter and method of making and using same

Abstract

The present application relates to the technical field of polarization beam splitter, and particularly relates to a polarization beam splitter, a preparation method and application thereof. The polarization beam splitter comprises a diamond substrate, a polarization beam splitting film and a first metalized film layer located on one side surface of the diamond substrate, a broadband antireflection film located on the other side surface of the diamond substrate, and a second metalized film layer located on the side surface of the diamond substrate; the first metalized film layer is located at the edge position of the one side surface of the diamond substrate. The diamond is used as the substrate material of the polarization beam splitter, and the heat generated by the laser acting on the film layer and the substrate can be rapidly conducted by using the high thermal conductivity of the diamond, so that the damage of the polarization beam splitter caused by the local temperature rise is relieved; the edge of the polarization beam splitter is subjected to the metalization treatment, so that the mirror body and the metal tube shell or the water cooling structure can be integrally welded, the heat conduction efficiency is improved, and a high reliability and low leakage rate vacuum sealing solution is provided.

Description

Technical Field

[0001] This invention relates to the field of polarization beam splitter technology, and in particular to a polarization beam splitter, its preparation method, and its application. Background Technology

[0002] 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.

[0003] 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.

[0004] 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

[0005] The purpose of this invention 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.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] The present invention provides a polarizing beam splitter, comprising 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.

[0008] The first metallization film layer 4-1 is located at the edge of one side surface of the diamond substrate 1.

[0009] 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;

[0010] The surface roughness of the side of the diamond substrate 1 is less than 1.6 μm.

[0011] Preferably, 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;

[0012] The base layer is a Ni-Cr alloy layer.

[0013] 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;

[0014] The thicknesses of the first metallization layer 4-1 and the second metallization layer 4-2 are independently 1.2 to 2.0 μm.

[0015] 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;

[0016] The material of the first high refractive index material layer is ZnSe;

[0017] The first low-refractive-index material layer is made of BaF2 doped with YbF3.

[0018] 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.

[0019] 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;

[0020] The material of the second high refractive index material layer is ZnSe;

[0021] The material of the second low-refractive-index material layer is BaF2 doped with YbF3.

[0022] 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.

[0023] The present invention also provides a method for preparing the polarizing beam splitter described in the above technical solution, comprising the following steps:

[0024] 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.

[0025] This invention 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.

[0026] The present invention provides a polarizing beam splitter, comprising 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.

[0027] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0028] 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.

[0029] 2) The present invention 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. On the one hand, it improves the heat conduction efficiency, and on the other hand, it can provide a high-reliability and low-leakage vacuum sealing solution.

[0030] Furthermore, this invention 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

[0031] Figure 1 This is a schematic diagram of the structure of the polarizing beam splitter of the present invention, wherein 1 is a diamond substrate, 2 is a polarizing beam splitting film, 3 is a broadband antireflection film, 4-1 is a first metallization film layer, and 4-2 is a second metallization film layer.

[0032] Figure 2 This is a flowchart illustrating the preparation process of the metallization film layer described in this invention.

[0033] Figure 3 The design spectrum of the polarization beam splitter described in Example 1;

[0034] Figure 4 The design spectrum is that of the broadband antireflection membrane described in Example 1. Detailed Implementation

[0035] like Figure 1 As shown, the present invention 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.

[0036] The first metallization film layer 4-1 is located at the edge of one side surface of the diamond substrate 1.

[0037] In this invention, 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 invention does not impose any special limitations on the source of the diamond substrate 1; any source well known to those skilled in the art can be used. In embodiments of this invention, the diamond substrate 1 can be prepared by chemical vapor deposition.

[0038] In this invention, the diamond substrate 1 has a diameter of 50 mm and a thickness of 2 mm.

[0039] In this invention, 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 invention does not have any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In an embodiment of this invention, the materials of the first metallization layer 4-1 and the second metallization layer 4-2 are the same and can be gold.

[0040] In this invention, 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 invention, the thicknesses of the first metallization layer 4-1 and the second metallization layer 4-2 can be 1.5 μm.

[0041] In this invention, the width of the first metallization film layer 4-1 can be 2 mm.

[0042] In this invention, 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.

[0043] In this invention, 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.

[0044] In this invention, 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 invention, 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 invention, the doping amount of YbF3 in the YbF3-doped BaF2 is preferably 0.5wt% to 5wt%. This invention 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 an embodiment of this invention, 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 an embodiment of the present invention, 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%.

[0045] In this invention, the center wavelength of the broadband antireflective coating 3 is preferably 11.0 μm; the broadband antireflective coating 3 uses (HL)^ 19H is used as the initial film system, and the optimization target value T ≥ 99.5% is given. In this invention, 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 invention 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 invention, 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 an embodiment of the present invention, the center wavelength of the broadband antireflection film 3 can be 11.0 μm; the broadband antireflection film 3 uses (HL)^ 19 H 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.

[0046] The present invention also provides a method for preparing the polarizing beam splitter described in the above technical solution, comprising the following steps:

[0047] 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.

[0048] In this invention, 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 invention, the deposition method is preferably resistive evaporation, electron beam evaporation, or sputtering. This invention 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 an embodiment of this invention, 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.

[0049] In this invention, a polarizing beam splitter 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 invention does not impose any special limitations on the process and related conditions for preparing the high and low refractive index material layers; conditions well-known to those skilled in the art can be used. In an embodiment of this invention, the preparation process of the polarizing beam splitter film 2 can be as follows: deposition is performed by resistance evaporation. Specifically, the diamond substrate with the completed metallized film layer is mounted, the vacuum chamber door is closed, and vacuuming is initiated until the background vacuum reaches 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.

[0050] In this invention, 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 invention 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 invention, 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.

[0051] This invention also provides the application of the polarizing beam splitter described in the above-described technical solutions or the polarizing beam splitter prepared by the above-described preparation methods in the field of infrared laser annealing devices or LPP-driven laser sources in EUV extreme ultraviolet lithography systems in the semiconductor chip industry. This invention does not impose any special limitations on the methods used for these applications; methods well-known to those skilled in the art can be employed.

[0052] The following detailed description of the polarizing beam splitter, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] 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 surface) was prepared using a lift-off process. The specific preparation process is as follows (e.g.) Figure 2 As shown, using 99.99% pure Au as the metallization film material: a 5μm thick photoresist is uniformly coated on one side of a diamond substrate. Exposure and development expose the deposited area of ​​the metallization film. The size of the photoresist-coated area after exposure and development is... 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 bombard and clean the diamond substrate for 5 min before plating. The ion source was turned off and the deposition of the metallization film began. A Ni-Cr alloy film was used as a base layer to improve the adhesion between the Au film and the diamond substrate. The Ni-Cr alloy film used a spiral tungsten wire as a resistance evaporation source with a deposition rate of 6.0 nm / s and a thickness of 50 nm. The Au film 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 sample was taken out of the vacuum chamber and the photoresist was peeled off to obtain a second metallization film 4-2 and a first metallization film 4-1 with a thickness of 1.5 μm.

[0055] 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. -3 At step 1, the workpiece disk was rotated at 10 rpm, and the substrate was heated to 160°C for 120 minutes. Then, the workpiece disk rotation was adjusted to 20 rpm, and the ion source was used to bombard and clean the diamond substrate for 5 minutes before plating. The ion source was then turned off, and the deposition of ZnSe and YbF3-doped BaF2 began. Both materials were deposited using a multi-position rotating resistance evaporation source at deposition rates of 4.0 nm / s and 5.0 nm / s, respectively. The polarization beam splitting film 2 was prepared according to the film structure shown in Table 1. After preparation, it was allowed to cool naturally to below 80°C before being removed from the vacuum chamber. The first high-refractive-index material layer in the polarization beam splitting film is ZnSe, and the first low-refractive-index material layer is YbF3-doped BaF2, with a YbF3 doping content of 1.5 wt%. The thickness is 36 μm, and the total number of layers is 31. Figure 3 The design spectrum of the polarizing beam splitter 2 is determined by... Figure 3It can be seen that the polarization beam splitter has Rs greater than 99% and Rp less than 0.1%.

[0056] Table 1. Materials and thicknesses of each layer of the polarization beam splitter film.

[0057]

[0058]

[0059] 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, wherein the YbF3 doping amount in the YbF3-doped BaF2 is 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 The design spectrum of the broadband antireflection film 3 is determined by... Figure 4 It can be seen that the transmittance of broadband antireflection membrane 3 is greater than 99.5%.

[0060] Table 2. Materials and thicknesses of each layer of the broadband antireflective coating.

[0061] Serial Number Material Film thickness(nm) Serial Number Material Film thickness(nm) Serial Number Material Film thickness(nm) 1 ZnSe 291.74 14 <![CDATA[BaF2]]> 1155 27 ZnSe 248.7 2 <![CDATA[BaF2]]> 665.89 15 ZnSe 395.76 28 <![CDATA[BaF2]]> 1917.14 3 ZnSe 693.48 16 <![CDATA[BaF2]]> 1555.71 29 ZnSe 126.74 4 <![CDATA[BaF2]]> 1465.36 17 ZnSe 424.46 30 <![CDATA[BaF2]]> 1025.36 5 ZnSe 575.11 18 <![CDATA[BaF2]]> 1418.21 31 ZnSe 217.61 6 <![CDATA[BaF2]]> 801.43 19 ZnSe 523.7 32 <![CDATA[BaF2]]> 355.54 7 ZnSe 266.63 20 <![CDATA[BaF2]]> 438.04 33 ZnSe 298.91 8 <![CDATA[BaF2]]> 1522.32 21 ZnSe 589.46 34 <![CDATA[BaF2]]> 206.25 9 ZnSe 571.52 22 <![CDATA[BaF2]]> 1086.25 35 ZnSe 860.87 10 <![CDATA[BaF2]]> 1215.89 23 ZnSe 607.39 36 <![CDATA[BaF2]]> 1648.04 11 ZnSe 817.83 24 <![CDATA[BaF2]]> 699.29 37 ZnSe 612.17 12 <![CDATA[BaF2]]> 1673.57 25 ZnSe 847.72 38 <![CDATA[BaF2]]> 1787.5 13 ZnSe 270.22 26 <![CDATA[BaF2]]> 310.36 39 ZnSe 339.57

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polarizing beamsplitter, characterized by, The polarized light splitting mirror comprises a diamond substrate (1), a broadband antireflection film (3) and a first metalized film layer (4-1) on one side surface of the diamond substrate (1), a polarized light splitting film (2) on the other side surface of the diamond substrate (1), and a second metalized film layer (4-2) on the side surface of the diamond substrate (1). The first metalized film layer (4-1) is located at the edge of the one side surface of the diamond substrate (1), and the broadband antireflection film (3) and the first metalized film layer (4-1) are located on the same side surface of the diamond substrate (1). The polarized light splitting film (2) comprises first high refractive index material layers and first low refractive index material layers which are cyclically and sequentially stacked, and the innermost layer and the outermost layer of the polarized light splitting film (2) are both first high refractive index material layers. The material of the first high refractive index material layers is ZnSe. The material of the first low refractive index material layers is BaF2 doped with YbF3. The broadband antireflection film (3) comprises second high refractive index material layers and second low refractive index material layers which are cyclically and sequentially stacked, and the innermost layer and the outermost layer of the broadband antireflection film (3) are both second high refractive index material layers. The material of the second high refractive index material layers is ZnSe. The material of the second low refractive index material layers is BaF2 doped with YbF3. The thickness of the broadband antireflection film (3) is 10-50 μm, and the total number of layers of the broadband antireflection film (3) is 39.

2. The polarizing beamsplitter of claim 1, wherein, The diamond substrate (1) is double-side polished, the RMS value of the optical surface shape is less than 1 / 50λ, and the surface roughness is less than 0.5 nm. The surface roughness of the side surface of the diamond substrate (1) is less than 1.6 μm.

3. The polarizing beamsplitter of claim 1, wherein, A primer layer is arranged between the diamond substrate (1) and the first metalized film layer (4-1) and between the diamond substrate (1) and the second metalized film layer (4-2). The primer layer is a Ni-Cr alloy layer.

4. The polarizing beamsplitter of claim 1, wherein, The material of the first metalized film layer (4-1) and the second metalized film layer (4-2) is independently one or more of gold, copper, chromium and nickel. The thickness of the first metalized film layer (4-1) and the second metalized film layer (4-2) is independently 1.2-2.0 μm.

5. The polarizing beamsplitter of claim 1, wherein, The thickness of the polarized light splitting film (2) is 10-50 μm, and the total number of layers of the polarized light splitting film (2) is 31.

6. The method of producing a polarizing beamsplitter according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: After the second metalized film layer (4-2) and the first metalized film layer (4-1) are prepared on the side surface and the edge of one side surface of the diamond substrate (1) respectively, the broadband antireflection film (3) is prepared on the remaining position of the one side surface of the diamond substrate (1), the polarized light splitting film (2) is prepared on the other side surface of the diamond substrate (1), and the polarized light splitting mirror is obtained.

7. The polarized light splitting mirror according to any one of claims 1-5 or prepared by the preparation method of claim 6 is applied in the field of infrared laser annealing devices in the semiconductor chip industry or LPP driven laser light sources in EUV photolithography systems.

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