Elements, devices, optical instruments

Abstract

There was a need for elements and devices that would not easily experience film peeling even after prolonged use. [Solution] An element comprising a substrate and a structure provided on the substrate, wherein the structure includes an aluminum compound film, and when the atomic concentration of aluminum relative to all elements in the aluminum compound film is [Al]at%, the atomic concentration of oxygen is [O]at%, the atomic concentration of fluorine is [F]at%, and the atomic concentration of hydrogen is [H]at%, at least one of 1at% ≤ [O]at% < 30at%, and [Al] / [O] > 2 / 3, and [F] / ([O]+[F]+[H]) ≥ 0.01, and [H] / ([O]+[F]+[H]) ≥ 0.01, and ([F]+[H]) / ([O]+[F]+[H]) ≥ 0.5.

Description

[Technical Field]

[0001] The present invention relates to an element comprising a film containing an aluminum compound, and to equipment, etc., equipped with said element. [Background technology]

[0002] Generally, optical elements such as lenses and mirrors are coated with optical films made of dielectric materials to improve their optical performance, such as transmittance and reflectivity. To enhance the optical performance of transmissive and reflective optical elements, optical films are often constructed in multiple layers, with a film configuration in which high refractive index materials and low refractive index materials are alternately layered. In this case, the high refractive index and low refractive index materials used must not only satisfy the desired refractive index but also not exhibit material-specific light absorption (light absorption at wavelengths shorter than the band gap) in the wavelength range in which they are used.

[0003] Patent Document 1 describes aluminum fluoride (AlF3) or aluminum fluoride oxide (AlO3). x F y It is disclosed that ) may be used as a low refractive index material. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-314746 [Overview of the project] [Problems that the invention aims to solve]

[0005] Patent Document 1 describes AlO with an O / F atomic ratio in the range of 0 to 10. x F yAn optical element coated with a film has been disclosed. However, when such an optical element is used continuously for a long period of time, film peeling occurs, resulting in a problem that the optical performance is greatly degraded. Therefore, there has been a demand for an optical element and an optical device in which film peeling is unlikely to occur even when used continuously for a long period of time. Also, in fields other than optical elements and optical devices, there has been a demand for an element and a device in which film peeling of an aluminum compound film containing fluorine is unlikely to occur even when used continuously for a long period of time.

Means for Solving the Problems

[0006] One aspect of the present invention is an element including a substrate and a structure provided on the substrate, wherein the structure includes an aluminum compound film, and when the atomic number concentration of aluminum in all elements in the aluminum compound film is [Al] at%, the atomic number concentration of oxygen is [O] at%, the atomic number concentration of fluorine is [F] at%, and the atomic number concentration of hydrogen is [H] at%, at least one of 1 at% ≦ [O] at% < 30 at% and [Al] / [O] > 2 / 3, and [F] / ([O] + [F] + [H]) ≧ 0.01, and [H] / ([O] + [F] + [H]) ≧ 0.01, and ([F] + [H]) / ([O] + [F] + [H]) ≧ 0.5 are satisfied. The element is characterized by this.

Effects of the Invention

[0007] According to the present invention, it is possible to realize an optical element and an optical device in which film peeling of an optical film is unlikely to occur even when used continuously for a long period of time. Also, in fields other than optical elements and optical devices, it is possible to realize an element and a device in which an aluminum compound film containing fluorine is unlikely to peel off even when used continuously for a long period of time.

Brief Description of the Drawings

[0008] [Figure 1] Schematic cross-sectional view of an optical element according to an embodiment. [Figure 2] Schematic diagram showing an example of a film forming apparatus used for forming an aluminum compound film. [Figure 3]Table 1 summarizing the content of each element, the environmental resistance evaluation results, the light absorption rate at a wavelength of 248 nm, and the refractive index at a wavelength of 248 nm for Examples 1 to 8 and Comparative Examples 1 to 4. [Figure 4] A figure mapping the relationship between the superiority or inferiority of environmental resistance and the content ratio of each element, with the total amount of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film normalized to 100%. [Figure 5] A figure mapping the relationship between the magnitude of the light absorption rate and the content ratio of each element, with the total amount of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film normalized to 100%. [Figure 6] A graph showing the light absorption rate spectra measured in the range of wavelengths from 180 nm to 280 nm for Example 1 and Comparative Example 1. [Figure 7] A figure mapping the relationship between the magnitude of the refractive index and the content ratio of each element, with the total amount of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film normalized to 100%. [Figure 8] A figure showing the relationship between the value of ([F] + [H]) / ([O] + [F] + [H]) and the refractive index. [Figure 9] A figure mapping the relationship between the content ratio of each element and whether the film with environmental resistance, light absorption rate, and refractive index all at levels suitable for practical use. The total amount of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film is normalized to 100%. [Figure 10] (a) Table 2 summarizing the materials of each layer of Example 9, the refractive index at a wavelength of 248 nm, and the physical film thickness. (b) Table 3 summarizing the materials of each layer of Comparative Example 5, the refractive index at a wavelength of 248 nm, and the physical film thickness. [Figure 11] A graph showing the wavelength characteristics of the transmittance for the transmissive optical elements of Example 9 and Comparative Example 5. [Figure 12] (a) Table 4 summarizing the materials of each layer of Example 10, the refractive index at a wavelength of 248 nm, and the physical film thickness. (b) Table 5 summarizing the materials of each layer of Comparative Example 6, the refractive index at a wavelength of 193 nm, and the physical film thickness. [Figure 13] Graphs showing the wavelength characteristics of transmittance for the transmissive optical elements of Example 10 and Comparative Example 6. [Figure 14] A schematic diagram of an exposure apparatus shown as an example of an optical device according to Embodiment 2. [Modes for carrying out the invention]

[0009] With reference to the drawings, an optical element and an optical device that are embodiments of the present invention will be described. Note that the embodiments shown below are illustrative, and for example, those skilled in the art can modify the detailed configuration as appropriate without departing from the spirit of the present invention.

[0010] In the drawings referenced in the following descriptions of embodiments and examples, elements denoted by the same reference numeral have the same function unless otherwise specified. In cases where multiple identical elements are shown in a drawing, the designation and description of the reference numeral may be omitted.

[0011] Furthermore, since drawings may be schematically represented for the convenience of illustration and explanation, the shape, size, and arrangement of elements shown in the drawings may not strictly correspond to those of actual objects. In addition, notations such as "XX or greater and YY or less" or "XX~YY" that indicate a numerical range mean a numerical range that includes the endpoints XX (lower limit) and YY (upper limit). When numerical ranges are described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0012] [Embodiment 1] (Configuration of optical elements) Figure 1 is a schematic cross-sectional view of an optical element according to this embodiment. The optical element 100 comprises a substrate 101 and an optical structure 102 provided on the substrate 101. The optical element 100 may be, for example, a lens, mirror, prism, or optical filter, but may also be any other optical element. Depending on the application and type of the optical element 100, the optical structure 102 may be provided as, for example, an anti-reflective structure that suppresses the reflection of target light, or as a reflective structure that promotes the reflection of target light.

[0013] The substrate 101 may be made of resin, glass, ceramics, metal, etc. The optical structure 102 is a film of an aluminum compound containing oxygen, fluorine, and hydrogen (hereinafter referred to as an aluminum compound film, or AlO x F y H z It has a membrane (sometimes referred to as a film).

[0014] The optical structure 102 may be a single-layer structure consisting only of an aluminum compound film 102a, or it may be a multilayer structure as illustrated in Figure 1. When the optical structure 102 is a multilayer structure, the aluminum compound film 102a is provided on the substrate 101. Furthermore, a dielectric layer 102b as a low refractive index layer and a dielectric layer 102c as a high refractive index layer having a higher refractive index than the dielectric layer 102b are provided on the aluminum compound film 102a.

[0015] The multilayer optical structure 102 may be a three-layer structure consisting of these three layers, or it may be a multilayer structure in which low-refractive-index layers and high-refractive-index layers are alternately stacked on top of the three layers. Here, among the multiple dielectric layers provided on the aluminum compound film 102a, dielectric layers with relatively high refractive index are collectively referred to as high-refractive-index layers, and dielectric layers with relatively low refractive index are collectively referred to as low-refractive-index layers. The optical structure 102 may be one in which high-refractive-index layers and low-refractive-index layers are alternately stacked. Here, "alternately stacked high-refractive-index layers and low-refractive-index layers" means that at least one low-refractive-index layer is located between two high-refractive-index layers, and at least one high-refractive-index layer is located between two low-refractive-index layers. Therefore, when high-refractive-index layers and low-refractive-index layers are alternately stacked, it means that at least four dielectric layers are provided.

[0016] The aluminum content of the aluminum compound film 102a relative to all elements is denoted as [Al]at%, the oxygen content as [O]at%, the fluorine content as [F]at%, and the hydrogen content as [H]at%. Here, "at%" means "atomic percentage," which is the ratio (atomic concentration) of a specific atom to the total number of atoms in the target. In addition to aluminum, oxygen, fluorine, and hydrogen, the aluminum compound film 102a may also contain other elements such as sputtering gas (e.g., argon) incorporated into the film during deposition, or impurities that are inevitably mixed in. Therefore, the total content (atomic concentration) of aluminum, oxygen, fluorine, and hydrogen in the film is not necessarily 100at%. If argon is present in the aluminum compound film 102a, the argon content relative to all elements in the aluminum compound film 102a is denoted as [Ar]at%. The elements constituting the aluminum compound film 102a may mostly consist of aluminum, oxygen, fluorine, and hydrogen. Specifically, [Al]+[O]+[F]+[H]≧90.0at% may also be [Al]+[O]+[F]+[H]≧95.0at% or [Al]+[O]+[F]+[H]≧99.0at%. Furthermore, [Al]+[O]+[F]+[H]+[Ar]≧95.0at% may also be [Al]+[O]+[F]+[H]+[Ar]≧99.0at% or [Al]+[O]+[F]+[H]+[Ar]≧99.9at%. Impurities that may be contained in the aluminum compound film 102a include carbon (C), nitrogen (N), and chlorine (Cl). It is preferable that the content of each of these carbon (C), nitrogen (N), and chlorine (Cl) is less than 0.1at%.

[0017] In the optical elements and optical devices of this embodiment, it is desirable that the refractive index of the aluminum compound film 102a be low, specifically that the refractive index for light with a wavelength of 248 nm is 1.53 or less. Furthermore, it is desirable that the light absorption rate of the aluminum compound film 102a be low, specifically that the light absorption rate at a wavelength of 248 nm is 0.2% or less, and more preferably 0.1% or less.

[0018] Materials used for the dielectric layer 102b, which serves as a low refractive index layer, include, but are not limited to, aluminum fluoride (AlF3), magnesium fluoride (MgF2), and silicon dioxide (SiO2). Materials containing these as the main components, or mixed materials, may also be used.

[0019] Materials used for the dielectric layer 102c, which serves as a high refractive index layer, include, but are not limited to, samarium fluoride (SmF3), lanthanum fluoride (LaF3), and aluminum oxide (Al2O3). Materials containing these as the main component, or mixed materials, may also be used.

[0020] When constructing an optical structure 102 that includes multiple high-refractive-index layers and multiple low-refractive-index layers, it is not necessary for all of the multiple high-refractive-index layers to be made of the same material, nor is it necessary for all of the multiple low-refractive-index layers to be made of the same material. For example, multiple high-refractive-index layers may be constructed using high-refractive-index layers made of different materials, such as using samarium fluoride (SmF3) for some of the layers and lanthanum fluoride (LaF3) for the remaining layers.

[0021] (Manufacturing method for optical elements) Figure 2 is a schematic diagram showing an example of a film deposition apparatus 300 used to deposit an aluminum compound film 102a. The example film deposition apparatus 300 is a film deposition apparatus that uses the sputtering method. The film deposition apparatus 300 has a vacuum chamber 301 as an airtight container and an exhaust system 302 for evacuating the vacuum chamber 301. It is also equipped with an argon gas introduction port 303, an oxygen gas introduction port 304, a hydrogen gas introduction port 305, and a fluorine-based gas introduction port 306 so that the gases necessary for film deposition can be introduced into the vacuum chamber 301. The fluorine-based gas introduced from the fluorine-based gas introduction port 306 may be fluorine (F2), carbon tetrafluoride (CF4), nitrogen trifluoride (NF3), hydrogen fluoride (HF), silicon tetrafluoride (SiF4), hydrofluoroolefin, etc., and at least one of these may be used.

[0022] Further, a sputtering target 307, a backing plate 308, a magnet mechanism 309, and a substrate holding mechanism 310 are provided in the vacuum chamber 301. By holding the substrate 101 of the optical element by the substrate holding mechanism 310 and applying power from the power supply 311, film formation can be carried out by the reactive sputtering method. At this time, the substrate holding mechanism 310 adjusts in advance the relative positional relationship between the sputtering target 307 and the film formation surface of the substrate 101 using a drive mechanism (not shown) so that the film thickness distribution within the surface of the substrate 101 becomes uniform.

[0023] The film formation method of the aluminum compound film 102a will be specifically described. To form the aluminum compound film 102a, film formation is carried out by the reactive sputtering method according to the following procedure. A substrate 101 made of, for example, quartz glass processed into a predetermined optical element shape and a metal aluminum (purity 99.9 wt% or more) which is the sputtering target 307 are installed in the vacuum chamber 301. At this time, the distance between the substrate 101 and the sputtering target 307 is, for example, 100 mm. Then, using the evacuation system 302, the inside of the vacuum chamber 301 is evacuated until the pressure reaches about 2.0×10 -4 Pa. After that, while introducing argon gas from the argon gas introduction port 303, oxygen gas from the oxygen gas introduction port 304, hydrogen gas from the hydrogen gas introduction port 305, and fluorine-based gas from the fluorine-based gas introduction port 306, plasma discharge is performed. As a result, an aluminum compound film 102a mainly composed of an aluminum compound is formed on the substrate 101. Plasma discharge suitable for film formation can be generated by applying power of, for example, 5 W / cm 2 from the power supply 311. Note that since known film formation methods can be used for the formation of the dielectric layer 102b and the dielectric layer 102c, the description thereof is omitted.

[0024] In the film deposition apparatus 300 illustrated in Figure 2, a single sputtering target 307 is set in the vacuum chamber 301. However, when fabricating a multilayer optical structure 102, multiple sputtering targets of different materials may be arranged. In this case, it is desirable to place shutters near the surface of each sputtering target to prevent other materials from adhering to the sputtering target surface during film deposition of other materials. In this embodiment, a sputtering method, particularly reactive sputtering, has been described, but the aluminum compound film may also be deposited by vacuum deposition, thermal CVD, plasma CVD, ADL, or the like.

[0025] (Evaluation method) Next, we will explain the evaluation methods for the fabricated optical films. We will then explain, in order, the methods for evaluating the components contained in the film, the methods for evaluating the optical properties of the film, and the methods for evaluating environmental resistance.

[0026] The hydrogen content in the aluminum compound film 102a can be evaluated by hydrogen forward scattering spectrometry (HFS). By irradiating the aluminum compound film 102a with a high-energy ion beam (e.g., He+) on the order of MeV, the amount and depth distribution of hydrogen contained in the film can be identified from the yield and energy of the forward-scattered hydrogen.

[0027] Elements other than hydrogen contained in the aluminum compound film 102a can be evaluated by irradiating it with a high-energy ion beam on the order of MeV and using Rutherford backscattering spectrometry (RBS).

[0028] Using these results, the hydrogen content [H]at%, aluminum content [Al]at%, oxygen content [O]at%, fluorine content [F]at%, hydrogen content [H]at%, and the content of other elements in the aluminum compound film 102a can be determined.

[0029] Regarding the evaluation of the optical properties of the film, transmittance and reflectance can be measured using a spectrophotometer, for example, in the wavelength range of 180 nm to 280 nm, at an incident light angle of 10 degrees. From the measured transmittance and reflectance results, the light absorption rate can be calculated using the following formula (1). A(%) = 100 - T(%) - R(%) ... (Equation 1) However, A represents the light absorptivity, which is the ratio of light absorption to incident light intensity; T represents the transmittance, which is the ratio of light transmission to incident light intensity; and R represents the reflectance, which is the ratio of light reflection to incident light intensity. Here, we will calculate the light absorptivity at a wavelength of 248 nm.

[0030] Regarding refractive index, the reflectance measurement results were obtained using FilmWizard, an optical thin film analysis and design software from Scientific Computing International. TM It can be calculated by analyzing it using [a specific method / tool]. Here, we calculate the refractive index at a wavelength of 248 nm.

[0031] Environmental resistance was evaluated by placing the fabricated optical element 100 into an environmental testing chamber set to a temperature of 60 degrees Celsius and a humidity of 80%, and leaving it there for 100 hours. The evaluation atmosphere was air. Visual inspection was performed on the appearance before and after placing it into the environmental test to check whether or not film peeling had occurred. The evaluation criteria for environmental resistance was that if no film peeling occurred at all after being left in an environmental testing chamber set to a temperature of 60 degrees Celsius and a humidity of 80%, and then visually inspected, it was evaluated as A. Although it is not the case that no film peeling occurs at all, AlO fabricated by the method disclosed in Patent Document 1 x F y Products that showed significantly improved environmental resistance compared to the film, i.e., less prone to delamination, were given a rating of B. In addition, AlO prepared by the method disclosed in Patent Document 1 was also evaluated. x F y Samples that showed no improvement in environmental resistance compared to the original film, i.e., those that experienced film delamination, were rated C.

[0032] (Examples and Comparative Examples) The following provides a detailed explanation with reference to examples and comparative examples. [Example 1] In Example 1, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 20 sccm, and hydrogen gas 20 sccm.

[0033] The aluminum compound film prepared in Example 1 had an aluminum content [Al] at% of 26.6 at%, an oxygen content [O] at% of 24.5 at%, a fluorine content [F] at% of 37.0 at%, and a hydrogen content [H] at% of 11.6 at%.

[0034] In this film, the light absorption rate at a wavelength of 248 nm was 0.02%, and the refractive index at a wavelength of 248 nm was 1.489, both of which were small values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as A. In Example 1, an optical film with good optical properties and environmental resistance was obtained.

[0035] [Example 2] In Example 2, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 35 sccm, and hydrogen gas 20 sccm.

[0036] The aluminum compound film prepared in Example 2 had an aluminum content [Al] at% of 24.4 at%, an oxygen content [O] at% of 18.9 at%, a fluorine content [F] at% of 44.4 at%, and a hydrogen content [H] at% of 11.8 at%.

[0037] In this film, the light absorption rate at a wavelength of 248 nm was 0.03%, and the refractive index at a wavelength of 248 nm was 1.458, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as A. In Example 2, an optical film with good optical properties and environmental resistance was obtained.

[0038] [Example 3] In Example 3, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 45 sccm, and hydrogen gas 2.0 sccm.

[0039] The aluminum compound film prepared in Example 3 had an aluminum content [Al] at% of 28.2 at%, an oxygen content [O] at% of 17.0 at%, a fluorine content [F] at% of 51.2 at%, and a hydrogen content [H] at% of 3.6 at%.

[0040] In this film, the light absorption rate at a wavelength of 248 nm was 0.09%, and the refractive index at a wavelength of 248 nm was 1.448, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as A. In Example 3, an optical film with good optical properties and environmental resistance was obtained.

[0041] [Example 4] In Example 4, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 15 sccm, and hydrogen gas 20 sccm.

[0042] The aluminum compound film prepared in Example 4 had an aluminum content [Al] at% of 26.5 at%, an oxygen content [O] at% of 26.5 at%, a fluorine content [F] at% of 32.8 at%, and a hydrogen content [H] at% of 13.8 at%.

[0043] In this film, the light absorption rate at a wavelength of 248 nm was 0.02%, and the refractive index at a wavelength of 248 nm was 1.486, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as A. In Example 4, an optical film with good optical properties and environmental resistance was obtained.

[0044] [Example 5] In Example 5, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 20 sccm, and hydrogen gas 1.0 sccm.

[0045] The aluminum compound film prepared in Example 5 had an aluminum content [Al] at% of 28.3 at%, an oxygen content [O] at% of 27.3 at%, a fluorine content [F] at% of 42.5 at%, and a hydrogen content [H] at% of 1.5 at%.

[0046] In this film, the light absorption rate at a wavelength of 248 nm was 0.18%, and the refractive index at a wavelength of 248 nm was 1.483, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as B. In Example 5, an optical film with good optical properties and environmental resistance was obtained.

[0047] [Example 6] In Example 6, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 30 sccm, fluorine gas 50 sccm, and hydrogen gas 15 sccm.

[0048] The aluminum compound film prepared in Example 6 had an aluminum content [Al] at% of 25.2 at%, an oxygen content [O] at% of 11.4 at%, a fluorine content [F] at% of 53.4 at%, and a hydrogen content [H] at% of 9.8 at%.

[0049] In this film, the light absorption rate at a wavelength of 248 nm was 0.00%, and the refractive index at a wavelength of 248 nm was 1.425, both of which were low values. After being left for 100 hours in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80%, the appearance was evaluated as B. In Example 6, an optical film with good optical properties and environmental resistance was obtained.

[0050] [Example 7] In Example 7, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 30 sccm, and hydrogen gas 50 sccm.

[0051] The aluminum compound film prepared in Example 7 had an aluminum content [Al] at% of 18.9 at%, an oxygen content [O] at% of 18.0 at%, a fluorine content [F] at% of 37.3 at%, and a hydrogen content [H] at% of 25.4 at%.

[0052] In this film, the light absorption rate at a wavelength of 248 nm was 0.18%, and the refractive index at a wavelength of 248 nm was 1.456, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as B. In Example 7, an optical film with good optical properties and environmental resistance was obtained.

[0053] [Example 8] In Example 8, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 40 sccm, fluorine gas 40 sccm, and hydrogen gas 15 sccm.

[0054] The aluminum compound film prepared in Example 8 had an aluminum content [Al] at% of 28.3 at%, an oxygen content [O] at% of 24.1 at%, a fluorine content [F] at% of 28.9 at%, and a hydrogen content [H] at% of 18.3 at%.

[0055] In this film, the light absorption rate at a wavelength of 248 nm was 0.06%, and the refractive index at a wavelength of 248 nm was 1.486, both of which were low values. After being left in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% for 100 hours, the appearance was evaluated as B. In Example 8, an optical film with good optical properties and environmental resistance was obtained.

[0056] [Comparative Example 1] In Comparative Example 1, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 50 sccm, fluorine gas 4.0 sccm, and hydrogen gas 20 sccm.

[0057] In the aluminum compound film prepared in Comparative Example 1, the aluminum content [Al] at% was 32.2 at%, the oxygen content [O] at% was 49.1 at%, the fluorine content [F] at% was 8.2 at%, and the hydrogen content [H] at% was 10.2 at%.

[0058] In this film, the light absorption rate at a wavelength of 248 nm was high at 0.91%, and the refractive index at a wavelength of 248 nm was also high at 1.663. The appearance after being left for 100 hours in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80% was evaluated as A. The optical film of Comparative Example 1 had good environmental resistance, but its optical properties were not practical due to its high light absorption rate and refractive index.

[0059] [Comparative Example 2] In Comparative Example 2, an aluminum compound film with a thickness of approximately 100 nm was deposited on a quartz glass substrate using the film deposition apparatus shown in Figure 2. During film deposition, the flow rates of argon gas introduced into the vacuum chamber 301 were 150 sccm, oxygen gas 50 sccm, fluorine gas 10 sccm, and hydrogen gas 15 sccm.

[0060] In the aluminum compound film prepared in Comparative Example 2, the aluminum content [Al] at% was 33.9 at%, the oxygen content [O] at% was 38.3 at%, the fluorine content [F] at% was 17.6 at%, and the hydrogen content [H] at% was 9.8 at%.

[0061] In this film, the light absorption rate at a wavelength of 248 nm was low at 0.14%, but the refractive index at 248 nm was high at 1.571. After being left for 100 hours in an environmental testing chamber set to a temperature of 60 degrees Celsius and a humidity of 80%, the appearance was evaluated as A. The optical film of Comparative Example 2 had good environmental resistance, but its optical properties were not practical due to its high refractive index.

[0062] [Comparative Example 3] In Comparative Example 3, using the film deposition apparatus shown in Figure 2, AlO was deposited onto a quartz glass substrate. x F yA film with a thickness of approximately 100 nm was deposited. During film deposition, the flow rates of argon gas, oxygen gas, and fluorine gas introduced into the vacuum chamber 301 were 150 sccm, 50 sccm, and 10 sccm, respectively. Hydrogen gas was not introduced.

[0063] AlO prepared in Comparative Example 3 x F y The aluminum content [Al] at% was 33.2 at%, the oxygen content [O] at% was 40.9 at%, the fluorine content [F] at% was 25.6 at%, and the hydrogen content [H] at% was 0.0 at%.

[0064] In this film, the light absorption rate at a wavelength of 248 nm was low at 0.15%, but the refractive index at 248 nm was high at 1.553. After being left for 100 hours in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80%, the appearance was rated C, and delamination of the film occurred. The optical film of Comparative Example 3 had a low light absorption rate, but its high refractive index and poor environmental resistance made it impractical.

[0065] [Comparative Example 4] In Comparative Example 4, using the film deposition apparatus shown in Figure 2, AlF was deposited onto a quartz glass substrate. y H z A film with a thickness of approximately 100 nm was deposited. During film deposition, the flow rates of argon gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 50 sccm, and 20 sccm, respectively. Oxygen gas was not introduced.

[0066] AlF prepared in Comparative Example 4 y H z The aluminum content [Al] at% was 24.2 at%, the oxygen content [O] at% was 0.0 at%, the fluorine content [F] at% was 66.3 at%, and the hydrogen content [H] at% was 9.4 at%.

[0067] In this film, the light absorption rate at a wavelength of 248 nm was 0.05%, and the refractive index at a wavelength of 248 nm was a low 1.335. However, after being left for 100 hours in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80%, the appearance was rated C, indicating that film delamination had occurred. The optical film of Comparative Example 4 had good optical properties, but was not practical due to its poor environmental resistance.

[0068] Table 1, shown in Figure 3, summarizes the content of each element, the environmental resistance evaluation results, the light absorption rate at a wavelength of 248 nm, and the refractive index at a wavelength of 248 nm for Examples 1 to 8 and Comparative Examples 1 to 4 described above. Since argon content was confirmed in the films of each sample, the argon content is listed as [Ar]at% in Table 1.

[0069] Referring to Figures 3 to 9, the conditions that the aluminum, oxygen, fluorine, and hydrogen contained in the aluminum compound film (i.e., aluminum compound film) provided by the optical element according to this embodiment must satisfy will be explained. The inventors of this application have found that not only the ratio (at%) of specific atoms to the total number of atoms in the film, but also the ratio of [O], [F], and [H] to the total amount of [O], [F], and [H] are related to environmental resistance, light absorption rate, and refractive index.

[0070] First, regarding environmental resistance, we will explain the conditions under which aluminum compound films possess practically superior properties. Figure 4 is a diagram that maps the relationship between the superiority or inferiority of environmental resistance and the content ratio of each element, normalized so that the total amount of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film equals 100%. Note that this is not a diagram where the total amount of all elements contained in the aluminum compound film equals 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Figure 4 also maps evaluation samples with different [O], [F], and [H] content ratios. The evaluation results for environmental resistance were based on the state of the film after being left for 100 hours in an environmental testing machine set to a temperature of 60 degrees Celsius and a humidity of 80%, as mentioned above.

[0071] Examples 1 to 8 have an environmental resistance rating of A or B, and possess properties suitable for practical use. As can be seen from Table 1 in Figure 3, they satisfy at least one of the conditions 1at% ≤ [O]at% < 30at% or [Al] / [O] > 3 / 2. Furthermore, as can be seen from Table 1, they satisfy either [H]at% ≥ 1at% or [F]at% ≥ 20at%.

[0072] In particular, Examples 1 to 4 received an A rating for environmental resistance and possess practically excellent properties. From Figure 4, these fall within the ranges 0.05 ≤ [H] / ([O]+[H]+[F]) ≤ 0.2 and 0.6 ≤ ([F]+[H]) / ([O]+[H]+[F]) ≤ 0.77. The latter can also be expressed as 0.23 ≤ [O] / ([O]+[H]+[F]) ≤ 0.4.

[0073] Comparative Example 3 received a rating of C for environmental resistance, which is an undesirable characteristic in practical terms, but it falls within the range of [H] < 1 at%. Generally, Al2O3 films that do not contain fluorine have high environmental resistance, but as the fluorine content increases beyond a certain point, environmental resistance tends to decrease. Even when a certain amount of fluorine is included, the inclusion of hydrogen tends to improve environmental resistance. It is presumed that Comparative Example 3 received a rating of C for environmental resistance because the hydrogen content was low relative to the fluorine content. In other words, it is presumed that when a certain amount of fluorine is included, environmental resistance will decrease unless an appropriate amount of hydrogen is also included. The exact reason for the film delamination is unclear, but in aluminum compound films with low hydrogen content, it is possible that the adhesion strength decreased due to increased internal stress, a large difference in thermal expansion coefficients between the substrate and the film, etc. Alternatively, it is possible that defects were generated in the film during the deposition of the aluminum compound film, and when the aluminum compound film with defects was left in a humid environment, moisture (i.e., OH groups) was mixed into the film, making the film brittle.

[0074] Comparative Example 4 received an environmental resistance rating of C, which is an undesirable characteristic for practical purposes. However, as can be seen from Table 1, it falls within the range of [O]at% < 1at%. The exact reason for delamination in aluminum compound films fabricated within the range including Comparative Example 4 is unclear, but it is possible that in aluminum compound films with low oxygen content and high fluorine content, the surface energy during film formation is lower, resulting in reduced adhesion. Furthermore, if the substrate of the aluminum compound film contains a material that can be etched by fluorine (fluorine compounds), the fluorine in the aluminum compound film or the fluorine during film formation may etch the substrate, potentially contributing to delamination. This effect may also occur if the coating film formed on the aluminum compound film contains a material that can be etched by fluorine (fluorine compounds), potentially contributing to delamination of the coating film. Such an effect can occur in film formation methods such as vapor deposition if fluorine is present. In this embodiment, since sputtering, a film formation method involving plasma generation, is used, active fluorine may be generated when fluorine is exposed to the plasma during film formation. The active fluorine may have had a strong etching effect on the substrate, potentially contributing to the occurrence of film delamination. In this embodiment, it can be considered that the presence of oxygen in the aluminum compound film suppresses film delamination caused by fluorine. Therefore, when using a film deposition method (sputtering method) involving plasma generation on a substrate that can be etched by fluorine (fluorine compounds), the aluminum compound film structure as in this embodiment is suitable.

[0075] In this regard, the aluminum compound films produced in the range including Examples 1 to 8, and especially in the range including Examples 1 to 4, may have suppressed internal stress and the difference in thermal expansion coefficients between the substrate and the layer because the amounts and proportions of oxygen, hydrogen, and fluorine contained in them were appropriate. Furthermore, the inclusion of an appropriate amount of hydrogen reduced the film defects formed during film formation, making it difficult for moisture (i.e., OH groups) to enter from the outside, and the surface energy during film formation was sufficiently large, which may have reduced the likelihood of film delamination.

[0076] Next, we will explain the conditions under which aluminum compound films have practically superior properties in terms of light absorption. Figure 5 is a diagram that maps the relationship between the magnitude of light absorption and the content ratio of each element, normalized so that the total amount of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film becomes 100%. Note that this is not a diagram in which the total amount of all elements contained in the aluminum compound film becomes 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Figure 5 also maps evaluation samples with different [O], [F], and [H] content ratios.

[0077] Examples 1 to 8 exhibit light absorption rates of 0.2% or less at a wavelength of 248 nm, demonstrating properties suitable for practical use. These examples fall within the ranges of [F] / ([O]+[F]+[H])≧0.2 and ([F]+[H]) / ([O]+[F]+[H])≧0.5. The latter can also be expressed as [O] / ([O]+[H]+[F])≦0.5. Furthermore, as shown in Table 1 of Figure 3, these examples fall within the range of [F]≧1at%.

[0078] In particular, Examples 1 to 4, 6, and 8 exhibit practically excellent properties, with a light absorption rate of 0.1% or less at a wavelength of 248 nm. These fall within the ranges 0.05 ≤ [H] / ([O]+[H]+[F]) ≤ 0.3 and ([F]+[H]) / ([O]+[H]+[F]) ≥ 0.63. The latter can also be expressed as [O] / ([O]+[H]+[F]) ≤ 0.37.

[0079] Comparative Example 1 exhibits a light absorption rate exceeding 0.2% at a wavelength of 248 nm, which is considered unsuitable for practical use. However, it falls within the ranges of [F] / ([O]+[F]+[H])<0.2 and ([F]+[H]) / ([O]+[F]+[H])<0.5. The latter can also be expressed as [O] / ([O]+[H]+[F])≧0.5. The exact reason for the high light absorption rate in the aluminum compound film layer fabricated within the range including Comparative Example 1 is unclear, but it is possible that the low fluorine content relative to the oxygen content caused significant material-specific light absorption within the wavelength range used. Additionally, the low hydrogen content may have resulted in insufficient filling of layer defects during the deposition of the aluminum compound film.

[0080] In this regard, in the aluminum compound films prepared within the range including Examples 1 to 8, particularly those within the range including Examples 1 to 4, 6, and 8, the fluorine content relative to the oxygen content is high. As a result, the wavelength band in which material-specific large light absorption occurs shifts to the shorter wavelength side, and it is possible that light absorption no longer occurs within the wavelength range used. In addition, it is possible that the addition of an appropriate amount of hydrogen compensated for defects in the aluminum compound film, thereby reducing light absorption.

[0081] Figure 6 shows the light absorption spectra of Example 1 and Comparative Example 1, measured in the ultraviolet region from 180 nm to 280 nm. Across the entire measurement range, Example 1 showed significantly lower light absorption than Comparative Example 1.

[0082] Next, we will explain the conditions for aluminum compound films to have practically superior properties regarding refractive index. Figure 7 is a diagram that maps the relationship between the magnitude of the refractive index and the content ratio of each element, normalized so that the total amount of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film equals 100%. Note that this is not a diagram where the total amount of all elements contained in the aluminum compound film equals 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Figure 7 also maps evaluation samples with different [O], [F], and [H] content ratios.

[0083] Furthermore, Figure 8 shows the relationship between the value of ([F]+[H]) / ([O]+[F]+[H]) and the refractive index. From Figure 8, it can be seen that in the range including Examples 1 to 8, the refractive index at a wavelength of 248 nm is 1.53 or less, indicating that it possesses properties suitable for practical use. From Figure 7, it can be seen that these examples are within the range of ([F]+[H]) / ([O]+[F]+[H])≧0.5. In addition, from Table 1 in Figure 3, it can be seen that these examples are within the range of [O]<30at%.

[0084] Figure 8 shows that in the range including Comparative Examples 1 to 3, the refractive index at a wavelength of 248 nm exceeds 1.53, indicating that these characteristics are unsuitable for practical use. These comparative examples fall within the range ([F]+[H]) / ([O]+[F]+[H])<0.5, as shown in Figure 7. The latter can also be expressed as [O] / ([O]+[H]+[F])>0.5.

[0085] Comparative Examples 1 to 3 are aluminum compound films with a high oxygen content and a composition similar to aluminum oxide (Al2O3), which may have resulted in an excessively high refractive index. In contrast, Examples 1 to 8 are aluminum compound films with a high fluorine content and a composition similar to aluminum fluoride (AlF3), which may have resulted in a suitably low refractive index. Furthermore, the high hydrogen content may have caused some of the hydrogen to penetrate between the lattice, reducing the film density and thus lowering the refractive index.

[0086] (Overall practical characteristics) Based on the results of the environmental resistance, light absorption rate, and refractive index studies described above, we will now describe the conditions for an aluminum compound film to possess overall practical properties, that is, for all three properties to be at a level suitable for practical use. Figure 9 is a diagram that maps the relationship between the level of overall practical properties and the content ratio of each element, normalized so that the total amount of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film becomes 100%. Note that this is not a diagram where the total amount of all elements contained in the aluminum compound film becomes 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Figure 9 also maps evaluation samples with different content ratios of [O], [F], and [H]. The level of overall practical properties is shown in three stages: unsuitable for practical use, suitable for practical use, and excellent practicality. The unsuitable level means that at least one of the three properties is not practical. The suitable level means that all three properties satisfy practicality requirements. A level of superior practicality means that all three characteristics satisfy the practical requirements, and at least one characteristic is at a level of superior practicality.

[0087] Examples 1 to 8 satisfy at least the practical requirements for all three properties, and as can be seen from Figure 9 and Table 1 in Figure 3, these are films that satisfy all of the following [film composition 1] to [film composition 4].

[0088] [Membrane composition 1] The oxygen content [O] at% is 1 at% or more and less than 30 at% or [Al] / [O] > 3 / 2, satisfying at least one of these conditions. That is, it satisfies at least one of the following conditions: 1at% ≤ [O]at% < 30at% and [Al] / [O] > 2 / 3.

[0089] [Membrane composition 2] [F] / ([O]+[F]+[H])≧0.01

[0090] [Membrane composition 3] [H] / ([O]+[F]+[H])≧0.01

[0091] [Membrane composition 4] ([F]+[H]) / ([O]+[F]+[H])≧0.5 Furthermore, membrane composition 4 can also be expressed as [O] / ([O]+[F]+[H])≦50%.

[0092] Furthermore, from Figure 9 and Table 1 in Figure 3, it can be seen that it is even more preferable to satisfy at least one of the following [film composition 5] to [film composition 16].

[0093] [Membrane composition 5] 10at% ≤ [Al]at% ≤ 40at%

[0094] [Membrane composition 6] [Al]at%≧[O]at%

[0095] [Membrane composition 7] [H] / ([O]+[F]+[H])≦0.5

[0096] [Membrane composition 8] [F]at%≧1at%

[0097] [Membrane composition 9] [F] / ([O]+[F]+[H])≧0.2

[0098] [Membrane composition 10] [F]at%≦60at%

[0099] [Membrane composition 11] [H]at%≧1at%

[0100] [Membrane composition 12] [H]at%≦30at%

[0101] [Membrane composition 13] [O]at%≧10at%

[0102] [Membrane composition 14] [Ar]at%≧0.1at%

[0103] [Membrane composition 15] [Ar]at%≦5at%

[0104] [Membrane composition 16] [Ar]at%<[H]at%

[0105] [Example 9] Next, as Example 9, a transmissive optical element is shown in which a multilayer optical structure containing the aluminum compound film of Example 1 is provided as an anti-reflective structure. As shown in Figure 1, an aluminum compound film 202a similar to that shown in Example 1 is laminated on a quartz glass substrate 101, and a total of five layers of low refractive index layers 202b and high refractive index layers 202c are stacked alternately on top of the aluminum compound film 202a to form the optical structure 102.

[0106] Magnesium fluoride (MgF2) was used as the low refractive index layer 202b, and samarium fluoride (SmF3) was used as the high refractive index layer 202c. Considering the intended use of the optical element 100, the transmittance was maximized at a wavelength of 248 nm, and the configuration of the optical structure was determined by optimizing the physical film thickness of each layer based on the refractive index of each layer. Although it is preferable to reduce the film thickness of the aluminum compound film 202a as much as possible to improve the transmittance characteristics, the film thickness was set to 10 nm in order to achieve sufficient environmental resistance.

[0107] Figure 10(a) shows Table 2, which summarizes the materials of each layer in this embodiment, the refractive index at a wavelength of 248 nm, and the physical film thickness. In the transmittance-type optical element of this embodiment, the transmittance for light at a wavelength of 248 nm was 99.8% at an incident light angle of 10 degrees, indicating very good anti-reflective function.

[0108] [Comparative Example 5] Comparative Example 5 shows a transmissive optical element in which a multilayer optical structure containing the aluminum compound film of Comparative Example 1 is provided as an anti-reflective structure. An aluminum compound film similar to that shown in Comparative Example 1 was laminated on a quartz glass substrate, and a total of five layers of alternating low-refractive-index and high-refractive-index layers were stacked on top of the aluminum compound film to form the optical structure. Magnesium fluoride (MgF2) was used as the low-refractive-index layer, and samarium fluoride (SmF3) was used as the high-refractive-index layer.

[0109] Figure 10(b) shows Table 3, which summarizes the materials of each layer in this comparative example, the refractive index at a wavelength of 248 nm, and the physical film thickness. In the transmittance-type optical element of this comparative example, the transmittance for light at a wavelength of 248 nm was 99.0% or less at a light incidence angle of 10 degrees. It can be presumed that the aluminum compound layer of Comparative Example 1 absorbed a lot of light due to its high light absorption rate, and that the anti-reflective performance of the optical structure was insufficient due to its high refractive index, resulting in a decrease in transmittance in the optical element of this comparative example.

[0110] Figure 11 shows the wavelength characteristics of transmittance for the transmissive optical elements of Example 9 and Comparative Example 5. Example 9 was confirmed to have good transmittance characteristics in a wavelength band of at least ±20 nm centered around 248 nm, and was confirmed to have an extremely high anti-reflective function compared to Comparative Example 5.

[0111] [Example 10] As Example 10, a transmissive optical element is shown in which a multilayer optical structure containing the aluminum compound film of Example 1 is provided as an anti-reflective structure. As shown in Figure 1, an aluminum compound film 202a similar to that shown in Example 1 is laminated on a quartz glass substrate 101, and a total of five layers of low refractive index layers 202b and high refractive index layers 202c are stacked alternately on top of the aluminum compound film 202a to form the optical structure 102.

[0112] Magnesium fluoride (MgF2) was used as the low refractive index layer 202b, and samarium fluoride (SmF3) was used as the high refractive index layer. Considering the intended use of the optical element 100, the transmittance was maximized at a wavelength of 193 nm, and the optical structure was constructed by optimizing the physical film thickness of each layer based on the refractive index of each layer. Although it is preferable to reduce the film thickness of the aluminum compound film 202a as much as possible to improve the transmittance characteristics, the film thickness was set to 10 nm in order to achieve sufficient environmental resistance.

[0113] Figure 12(a) shows Table 4, which summarizes the materials of each layer in this embodiment, the refractive index at a wavelength of 248 nm, and the physical film thickness. In the transmittance-type optical element of this embodiment, the transmittance for light with a wavelength of 193 nm was 99.7% at an incident light angle of 10 degrees, indicating very good anti-reflective function.

[0114] [Comparative Example 6] Comparative Example 6 shows a transmissive optical element in which a multilayer optical structure containing the aluminum compound film of Comparative Example 1 is provided as an anti-reflective structure. An aluminum compound film similar to that shown in Comparative Example 1 was laminated on a quartz glass substrate, and a total of five layers of alternating low-refractive-index and high-refractive-index layers were stacked on top of the aluminum compound film to form the optical structure. Magnesium fluoride (MgF2) was used as the low-refractive-index layer, and samarium fluoride (SmF3) was used as the high-refractive-index layer.

[0115] Figure 12(b) shows Table 5, which summarizes the materials of each layer in this comparative example, the refractive index at a wavelength of 193 nm, and the physical film thickness. In the transmittance-type optical element of this comparative example, the transmittance for light at a wavelength of 193 nm was 98.0% or less at a light incidence angle of 10 degrees. The aluminum compound film in Comparative Example 1 has a high light absorption rate, so a lot of light is absorbed, and its high refractive index results in insufficient anti-reflective performance of the optical structure, which can be presumed to have led to a decrease in transmittance in the optical element of this comparative example. Furthermore, in this comparative example, because the wavelength of the target light is short at 193 nm, the effect of light absorption rate is greater than at a wavelength of 248 nm, resulting in a worse transmittance characteristic than in Comparative Example 5, where the wavelength of the target light was 248 nm.

[0116] Figure 13 shows the wavelength characteristics of transmittance for the transmissive optical elements of Example 10 and Comparative Example 6. Example 10 was confirmed to have good transmittance characteristics in a wavelength band of at least ±10 nm centered around 193 nm, and was confirmed to have an extremely high anti-reflective function compared to Comparative Example 6.

[0117] In Example 9, the central wavelength of the target light handled by the optical element was set to 248 nm, and in Example 10, the central wavelength of the target light was set to 193 nm. However, the target light handled by the optical element according to this embodiment is not limited to these examples. The optical properties of the optical structure can be optimized by appropriately changing the material composition of the aluminum compound film, the materials and number of layers for the low refractive index layer and the high refractive index layer, and the physical thickness of each layer, according to the light source used and the purpose of use of the optical element.

[0118] [Embodiment 2] As Embodiment 2, an optical device equipped with the optical element described in Embodiment 1 will be described. The optical element described in Embodiment 1 is applicable to various optical devices, such as camera lenses, telescopes, projectors, exposure devices, and measuring instruments. In particular, the optical element 100 of Embodiment 1 is suitably applicable to optical devices equipped with a light source, such as projectors, exposure devices, and measuring instruments. This is because the transmission and / or reflection characteristics of the optical structure 102 can be designed to match the wavelength of the light source. The light from the light source may be infrared light, visible light, or ultraviolet light, but if the optical element has the characteristic of being able to suppress the absorption of ultraviolet light as in the above-described embodiment, it can be particularly suitably implemented in devices where the light source is ultraviolet light.

[0119] Figure 14 shows a schematic diagram of an exposure apparatus 200 as an example of an optical device according to Embodiment 2. The exposure apparatus 200 comprises a light source 201, mirrors 202 and 203 constituting the illumination optical system, a reticle stage 205 as a support for the reticle 204, a projection optical system 206 for projecting the pattern of the reticle 204, and a substrate stage 208 on which a substrate 207 is mounted. Mirrors 202 and 203 of the illumination optical system are optical elements according to Embodiment 1, and are made of an aluminum compound film (AlO x F y H z A multilayer film containing a film is formed as an optical structure (reflective film).

[0120] A photoresist is coated on the substrate 207, and the photoresist is exposed by exposure light 209. The substrate 207 may be a semiconductor wafer (semiconductor substrate) or a glass substrate for FPD (flat panel display). The exposure light of the exposure apparatus 200 is typically ultraviolet light. The wavelength of the exposure light is not particularly limited, but for example, it is about 365 nm for an i-line light source, about 248 nm for a KrF excimer laser light source, and about 193 nm for an ArF excimer laser light source. It is also about 157 nm for an F2 excimer laser light source and 10-20 nm for an EUV (extreme ultraviolet) light source.

[0121] In this embodiment, an example is shown in which the optical elements according to Embodiment 1 are applied to mirrors 202 and 203 of the illumination optical system. However, the application is not particularly limited, and for example, it may be a lens in a projection optical system. Alternatively, the projection optical system may be composed of mirrors, and the optical elements according to Embodiment 1 may be applied to those mirrors. The projection optical system may be a reduction projection type, a 1:1 projection type, or a magnification projection type. Here, a transmissive reticle is exemplified as the reticle 204, but a reflective reticle may also be used. The projection optical system may be a refractive type using lenses, or a reflective type using mirrors. The optical elements according to Embodiment 1 may be applied to the mirrors of a reflective reduction projection optical system in an exposure apparatus equipped with an EUV light source.

[0122] In recent years, efforts have been made to improve the production capacity of exposure equipment. For example, in exposure equipment equipped with KrF excimer laser light as a light source, aluminum compound films (AlO) that have low light absorption at wavelengths below 300 nm are being considered. x F y H z When using a film, improving environmental resistance can prevent deterioration of optical performance over time. By applying the optical element according to Embodiment 1, it becomes possible to maintain high throughput even after prolonged use, thereby realizing an exposure apparatus with high production capacity.

[0123] [Other embodiments] It should be noted that the present invention is not limited to the embodiments and examples described above, and many modifications are possible within the technical concept of the present invention. For example, all or part of the different embodiments and examples described above may be combined and implemented.

[0124] In the above description of embodiments, optical elements such as lenses, mirrors, prisms, and optical filters were given as examples of elements equipped with an aluminum compound film, but the elements that implement the present invention are not limited to optical elements. The present invention can be implemented in elements for various applications such as image sensors, display elements, light-emitting elements, and exterior components, or in elements of various types such as semiconductor elements, electrical elements, and mechanical elements. To give an example of implementation in an image sensor or semiconductor element, for example, in a CMOS sensor or CCD sensor, the above-mentioned aluminum compound film (AlO) can be used as an anti-reflective film in the pixel area. x F y H z A film can be provided. Furthermore, if it is a display element or light-emitting element, it can be implemented in an OLED (Organic Light Emitting Diode) element, for example. As a protective film for the display pixel or light-emitting part, the above-mentioned aluminum compound film (AlO) which has low light loss and high environmental resistance can be provided. x F y H zThe above-mentioned aluminum compound film (AlO) can be suitably used. Examples of exterior parts or mechanical elements include, for example, the casings and mechanical parts of automobiles or other devices made by hot pressing aluminum-plated steel sheets. x F y H z By providing an aluminum compound film (AlO), it is possible to provide mechanical elements with a good appearance and excellent environmental resistance. x F y H z The operating environment for the element equipped with the film is not limited to an atmospheric environment, but may also be a vacuum environment or a gaseous atmosphere other than air.

[0125] In the above explanation, aluminum compound film (AlO x F y H z As examples of devices equipped with elements having a film (visual element), optical devices such as camera lenses, telescopes, projectors, exposure devices, and measuring instruments were given, with exposure devices being explained in particular detail. However, the devices to which this invention can be implemented are not limited to optical devices. For example, by incorporating the aforementioned optical elements, image sensors, display elements, light-emitting elements, mechanical elements, etc., into communication devices such as smartphones, or mobile or transportation devices such as automobiles and drones, the present invention can be suitably implemented in various devices.

[0126] Furthermore, if this specification contains a statement such as "A is B," even if it omits a statement such as "A is not B," it can be said that this specification discloses that "A is not B." This is because the statement "A is B" implies that the case where "A is not B" is being considered.

[0127] This specification discloses at least the following configuration: [Configuration 1] An element comprising a substrate and a structure provided on the substrate, The aforementioned structure includes an aluminum compound film, When the atomic concentration of aluminum relative to all elements in the aluminum compound film is [Al]at%, the atomic concentration of oxygen is [O]at%, the atomic concentration of fluorine is [F]at%, and the atomic concentration of hydrogen is [H]at%, At least one of 1at% ≤ [O]at% < 30at%, and [Al] / [O] > 2 / 3, and [F] / ([O]+[F]+[H])≧0.01, and [H] / ([O]+[F]+[H])≧0.01, and ([F]+[H]) / ([O]+[F]+[H])≧0.5, An element characterized by the following features. [Configuration 2] Satisfying 10at% ≤ [Al]at% ≤ 40at%, The element according to configuration 1, characterized by the above. [Configuration 3] [Al]at% ≥ [O]at%, The element according to configuration 1 or 2, characterized by the above. [Structure 4] Satisfying [H] / ([O]+[F]+[H])≦0.5, The element according to any one of configurations 1 to 3, characterized by the above. [Composition 5] [F] satisfies the condition at% ≥ 1at%, An element according to any one of configurations 1 to 4, characterized by the above. [Composition 6] [F] / ([O]+[F]+[H])≧0.2 An element according to any one of configurations 1 to 5, characterized by the above. [Composition 7] [F] satisfies the condition at ≤ 60at%, The element according to any one of configurations 1 to 6, characterized by the above. [Structure 8] [H] satisfies the condition: at% ≥ 1at%, An element according to any one of configurations 1 to 7, characterized by the above. [Composition 9] [H] satisfies ≤ 30at%, The element according to any one of configurations 1 to 8. [Configuration 10] [O] satisfies ≥ 10at%, An element according to any one of configurations 1 to 9, characterized by the above. [Composition 11] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar]at%≧0.1at%, satisfying the condition An element according to any one of configurations 1 to 10, characterized by the above. [Composition 12] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar]at% ≤ 5at%, An element according to any one of configurations 1 to 11, characterized by the features described herein. [Composition 13] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar]at%<[H]at%, satisfying the condition An element according to any one of configurations 1 to 12, characterized in that it is a component of the configuration described in any one of the above. [Composition 14] The aforementioned structure is an optical structure. The element according to any one of configurations 1 to 13, characterized by the features described herein. [Composition 15] The optical structure has an anti-reflective structure. The element according to configuration 14, characterized by the features described above. [Composition 16] The optical structure has a reflective structure, The element according to configuration 14, characterized by the features described above. [Composition 17] The optical structure comprises a low refractive index layer and a high refractive index layer laminated on the aluminum compound film. The element according to any one of the configurations 14 to 16, characterized by the features described herein. [Composition 18] The aluminum compound film has a refractive index of 1.53 or less for light with a wavelength of 248 nm. An element according to any one of configurations 1 to 17, characterized by the above. [Composition 19] The aforementioned aluminum compound film has a light absorption rate of 0.2% or less for light with a wavelength of 248 nm. An element according to any one of configurations 1 to 18, characterized in that it is a component. [Configuration 20] The aforementioned substrate is a substrate for an optical element. An element according to any one of configurations 1 to 19, characterized by the features described herein. [Composition 21] The optical element is one of a lens, mirror, prism, or optical filter. The element according to configuration 20, characterized by the above. [Composition 22] The element described in any one of configurations 1 to 21, A support that supports the aforementioned device, Equipment equipped with these features. [Composition 23] The system comprises a light source, an illumination optical system that guides the light emitted by the light source to a reticle, and a projection optical system that projects the pattern of the reticle onto a substrate. At least one of the illumination optical system and the projection optical system comprises the element described in any one of configurations 1 to 21. An optical instrument characterized by the following features. [Explanation of Symbols]

[0128] 100...Optical element / 101...Substrate / 102...Optical structure / 102a...Aluminum compound film / 102b...Dielectric layer / 102c...Dielectric layer / 200...Exposure apparatus / 201...Light source / 202, 203...Mirror / 204...Reticle / 205...Reticle stage / 206...Projection optical system / 207...Substrate / 208...Substrate stage / 3 00...Film deposition apparatus / 301...Vacuum chamber / 302...Exhaust system / 303...Argon gas introduction port / 304...Oxygen gas introduction port / 305...Hydrogen gas introduction port / 306...Fluorine-based gas introduction port / 307...Sputtering target / 308...Backing plate / 309...Magnetic mechanism / 310...Substrate holding mechanism / 311...Power supply

Claims

1. An element comprising a substrate and a structure provided on the substrate, The aforementioned structure includes an aluminum compound film, When the atomic concentration of aluminum relative to the total elements in the aluminum compound film is [Al] at%, the atomic concentration of oxygen is [O] at%, the atomic concentration of fluorine is [F] at%, and the atomic concentration of hydrogen is [H] at%, At least one of 1 at% ≤ [O] at% < 30 at%, and [Al] / [O] > 2 / 3, and [F] / ([O]+[F]+[H])≧0.01, and [H] / ([O]+[F]+[H])≧0.01, and ([F] + [H]) / ([O] + [F] + [H]) ≥ 0.5, An element characterized by the following features.

2. Satisfying the conditions 10 at% ≤ [Al] at% ≤ 40 at%, The element according to feature 1.

3. [Al]at% ≥ [O]at%, The element according to feature 1.

4. Satisfying [H] / ([O]+[F]+[H])≦0.5, The element according to feature 1.

5. [F] Satisfying the condition at% ≥ 1at%, The element according to feature 1.

6. [F] / ([O]+[F]+[H])≧0.2 The element according to feature 1.

7. [F] satisfies at% ≤ 60at%, The element according to feature 1.

8. [H] satisfies at% ≥ 1at%, The element according to feature 1.

9. [H] satisfies the condition at% ≤ 30at%, The element according to feature 1.

10. [O] satisfies the condition at% ≥ 10at%, The element according to feature 1.

11. When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar] at% ≥ 0.1 at%, The element according to feature 1.

12. When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar] at% ≤ 5 at%, The element according to feature 1.

13. When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar]at%, [Ar]at% < [H]at%, The element according to feature 1.

14. The aforementioned structure is an optical structure. The element according to any one of claims 1 to 13.

15. The optical structure has an anti-reflective structure. The element according to feature 14.

16. The optical structure has a reflective structure, The element according to feature 14.

17. The optical structure comprises a low refractive index layer and a high refractive index layer laminated on the aluminum compound film. The element according to feature 14.

18. The aluminum compound film has a refractive index of 1.53 or less for light with a wavelength of 248 nm. The element according to any one of claims 1 to 13.

19. The aluminum compound film has a light absorption rate of 0.2% or less for light with a wavelength of 248 nm. The element according to any one of claims 1 to 13.

20. The aforementioned substrate is a substrate for an optical element. The element according to any one of claims 1 to 13.

21. The optical element is one of a lens, mirror, prism, or optical filter. The element according to feature 20.

22. The element according to any one of claims 1 to 13, A support that supports the aforementioned device, Equipment equipped with these features.

23. The system comprises a light source, an illumination optical system that guides the light emitted by the light source to a reticle, and a projection optical system that projects the pattern of the reticle onto a substrate. At least one of the illumination optical system and the projection optical system comprises the element described in any one of claims 1 to 13. An optical instrument characterized by the following features.

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