Elements, equipment, optical equipment

Abstract

To solve the problem in which: there has been a demand for a device and an apparatus preventing peeling off of a film despite a long period of continuous use.SOLUTION: A device comprises a substrate and a structure provided on the substrate. The structure includes an aluminum compound film. When, relative to all elements in the aluminum compound film, the atomic number concentration of aluminum is defined as [Al] at%, the atomic number concentration of oxygen as [O] at%, the atomic number concentration of fluorine as [F] at%, and the atomic number concentration of hydrogen as [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.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an element provided with a film containing an aluminum compound, and a device or the like provided with the element. [Background technology]

[0002] Optical elements such as lenses and mirrors are generally coated with optical films made of dielectric materials to improve optical performance such as transmittance and reflectance. To improve the optical performance of transmissive and reflective optical elements, optical films are often made up of multiple layers, with high-refractive-index materials and low-refractive-index materials alternately stacked. In this case, the high-refractive-index and low-refractive-index materials used must not only satisfy the desired refractive index, but also must not exhibit material-specific optical absorption (optical absorption at wavelengths shorter than the band gap) in the wavelength range to be used.

[0003] Patent Document 1 describes a method for producing aluminum fluoride (AlF3) or aluminum oxide fluoride (AlO x F y ) as a low refractive index material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-314746 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 describes AlO in which the O / F atomic ratio is in the range of 0 to 10. x F yAlthough optical elements coated with a film have been disclosed, when such optical elements are used for a long period of time, film peeling occurs, resulting in a problem of a significant deterioration in optical performance. Therefore, there has been a demand for optical elements and optical devices that are less likely to peel even when used for a long period of time. Furthermore, in fields other than optical elements and optical devices, there has also been a demand for elements and devices in which fluorine-containing aluminum compound films are less likely to peel even when used for a long period of time. [Means for solving the problem]

[0006] One aspect of the present invention is an element comprising a substrate and a structure provided on the substrate, the structure including an aluminum compound film, wherein, where 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 1 at %≦[O] at %<30 at % and [Al] / [O]>2 / 3 is satisfied, and [F] / ([O]+[F]+[H])≧0.01, [H] / ([O]+[F]+[H])≧0.01, and ([F]+[H]) / ([O]+[F]+[H])≧0.5 is satisfied. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize optical elements and optical devices in which peeling of the optical film is unlikely to occur even after long-term use. Furthermore, in fields other than optical elements and optical devices, it is possible to realize elements and devices in which peeling of the fluorine-containing aluminum compound film is unlikely to occur even after long-term use. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of an optical element according to an embodiment. [Figure 2] FIG. 1 is a schematic diagram showing an example of a film forming apparatus used to form an aluminum compound film. [Figure 3]Table 1 shows the content of each element, the results of the environmental resistance evaluation, the light absorptance 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] The relationship between the environmental resistance and the content ratio of each element is mapped by normalizing the total of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film to 100%. [Figure 5] The relationship between the magnitude of light absorption rate and the content ratio of each element is mapped, with the total of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film normalized to 100%. [Figure 6] 1 is a graph showing the light absorptance spectra measured in the wavelength range of 180 nm to 280 nm for Example 1 and Comparative Example 1. [Figure 7] The relationship between the refractive index and the content ratio of each element is mapped, with the total of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film normalized to 100%. [Figure 8] A graph showing the relationship between the value of ([F]+[H]) / ([O]+[F]+[H]) and the refractive index. [Figure 9] The total amount of [O]at%, [F]at%, and [H]at% contained in the aluminum compound film is normalized to 100%, and the relationship between the content ratio of each element and whether the film is at a level suitable for practical use in terms of environmental resistance, light absorption rate, and refractive index is mapped. [Figure 10] (a) Table 2 shows the material, refractive index at a wavelength of 248 nm, and physical film thickness of each layer in Example 9. (b) Table 3 shows the material, refractive index at a wavelength of 248 nm, and physical film thickness of each layer in Comparative Example 5. [Figure 11] 10 is a graph showing the wavelength characteristics of transmittance for the transmissive optical elements of Example 9 and Comparative Example 5. [Figure 12] (a) Table 4 shows the material, refractive index at a wavelength of 248 nm, and physical film thickness of each layer in Example 10. (b) Table 5 shows the material, refractive index at a wavelength of 193 nm, and physical film thickness of each layer in Comparative Example 6. [Figure 13] 10 is a graph showing the wavelength characteristics of transmittance for the transmissive optical elements of Example 10 and Comparative Example 6. [Figure 14] FIG. 10 is a schematic diagram of an exposure apparatus shown as an example of an optical apparatus according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes optical elements and optical instruments according to embodiments of the present invention with reference to the drawings. Note that the embodiments shown below are merely examples, and those skilled in the art can appropriately modify and implement the detailed configurations within the scope of the present invention without departing from the spirit and scope of the present invention.

[0010] In the drawings referred to in the following description of the embodiments and examples, elements denoted by the same reference numerals have the same functions unless otherwise specified. When a plurality of identical elements are arranged in a drawing, the reference numerals and their descriptions may be omitted.

[0011] In addition, because the drawings may be represented schematically for the convenience of illustration and explanation, the shape, size, and arrangement of elements depicted in the drawings may not strictly correspond to the actual objects. Furthermore, the descriptions "XX or more and YY or less" and "XX to YY" that represent a numerical range mean a numerical range including the endpoints XX (lower limit) and YY (upper limit), unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0012] [Embodiment 1] (Configuration of optical elements) 1 is a schematic cross-sectional view of an optical element according to this embodiment. The optical element 100 includes a base 101 and an optical structure 102 provided on the base 101. The optical element 100 may be, for example, a lens, a mirror, a prism, or an 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-reflection structure that suppresses reflection of target light, or as a reflective structure that promotes reflection of target light.

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

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

[0015] The multilayer optical structure 102 may have a three-layer structure consisting of these three layers, or may have 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, the dielectric layers with relatively high refractive indexes are collectively referred to as high-refractive-index layers, and the dielectric layers with relatively low refractive indexes are collectively referred to as low-refractive-index layers. The optical structure 102 may have high-refractive-index layers and low-refractive-index layers alternately stacked. Here, "high-refractive-index layers and low-refractive-index layers alternately stacked" 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, "high-refractive-index layers and low-refractive-index layers alternately stacked" means that at least four dielectric layers are provided.

[0016] The aluminum content of the aluminum compound film 102a relative to all elements is expressed as [Al] at%, the oxygen content as [O] at%, the fluorine content as [F] at%, and the hydrogen content as [H] at%. Here, "at%" refers to "atomic percentage," which is the ratio of a specific atom to the total number of atoms in a target (atomic concentration). The aluminum compound film 102a may contain, in addition to aluminum, oxygen, fluorine, and hydrogen, impurities such as sputtering gas (e.g., argon) introduced into the film during film formation or other unavoidable impurities. Therefore, the total content (atomic concentration) of aluminum, oxygen, fluorine, and hydrogen in the film does not necessarily equal 100 at%. When the aluminum compound film 102a contains argon, the argon content relative to all elements in the aluminum compound film 102a is expressed as [Ar] at%. Most of the elements constituting the aluminum compound film 102a may be aluminum, oxygen, fluorine, and hydrogen. Specifically, the aluminum compound film 102a may have a composition ratio of [Al] + [O] + [F] + [H] ≥ 90.0 at %, [Al] + [O] + [F] + [H] ≥ 95.0 at %, or [Al] + [O] + [F] + [H] ≥ 99.0 at %. The aluminum compound film 102a may also have a composition ratio of [Al] + [O] + [F] + [H] + [Ar] ≥ 95.0 at %, [Al] + [O] + [F] + [H] + [Ar] ≥ 99.0 at %, or [Al] + [O] + [F] + [H] + [Ar] ≥ 99.9 at %. Examples of impurities that may be contained in the aluminum compound film 102a include carbon (C), nitrogen (N), and chlorine (Cl). The content of each of these elements is preferably less than 0.1 at %.

[0017] In the optical element and optical device of this embodiment, the refractive index of the aluminum compound film 102a is preferably low, specifically, the refractive index for light with a wavelength of 248 nm is preferably 1.53 or less. The light absorptance of the aluminum compound film 102a is also preferably low, specifically, the light absorptance at a wavelength of 248 nm is preferably 0.2% or less, and more preferably 0.1% or less.

[0018] Materials used for the dielectric layer 102b as a low refractive index layer include, but are not limited to, aluminum fluoride (AlF), magnesium fluoride (MgF), silicon oxide (SiO), etc. Materials containing these as main components or mixed materials may also be used.

[0019] Materials used for the dielectric layer 102c as a high refractive index layer include, but are not limited to, samarium fluoride (SmF), lanthanum fluoride (LaF), aluminum oxide (AlO), etc. Materials containing these as main components or mixed materials may also be used.

[0020] When configuring the optical structure 102 having a plurality of high-refractive-index layers and a plurality of low-refractive-index layers, it is not necessary for all of the high-refractive-index layers to be made of the same material, and it is also not necessary for all of the low-refractive-index layers to be made of the same material. For example, the plurality of high-refractive-index layers may be configured using high-refractive-index layers of different materials, such as some of the layers being made of samarium fluoride (SmF3) and the remaining layers being made of lanthanum fluoride (LaF3).

[0021] (Method of manufacturing optical elements) 2 is a schematic diagram showing an example of a film formation apparatus 300 used to form the aluminum compound film 102a. The illustrated film formation apparatus 300 is a film formation apparatus using a sputtering method. The film formation apparatus 300 has a vacuum chamber 301 as an airtight container and an exhaust system 302 for evacuating the vacuum chamber 301. In addition, the film formation apparatus 300 is equipped with an argon gas inlet port 303, an oxygen gas inlet port 304, a hydrogen gas inlet port 305, and a fluorine-based gas inlet port 306 so that gases necessary for film formation can be introduced into the vacuum chamber 301. The fluorine-based gas introduced through the fluorine-based gas inlet port 306 can be fluorine (F), carbon tetrafluoride (CF), nitrogen trifluoride (NF), hydrogen fluoride (HF), silicon tetrafluoride (SiF), hydrofluoroolefin, or the like, and at least one of these can be used.

[0022] Furthermore, attached to the vacuum chamber 301 are a sputtering target 307, a backing plate 308, a magnet mechanism 309, and a substrate holding mechanism 310. By holding the substrate 101 of the optical element on the substrate holding mechanism 310 and applying power from a power supply 311, film formation can be carried out by a 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 is constant.

[0023] A method for forming the aluminum compound film 102a will be specifically described. To form the aluminum compound film 102a, film formation is performed by a reactive sputtering method in the following procedure. A substrate 101 made of, for example, quartz glass and processed into the shape of a predetermined optical element, and metallic aluminum (with a purity of 99.9 wt% or more) serving as a sputtering target 307 are placed in a vacuum chamber 301. At this time, the distance between the substrate 101 and the sputtering target 307 is set to, for example, 100 mm. Then, an exhaust system 302 is used to reduce the pressure to 2.0×10 -4 The vacuum chamber 301 is evacuated to about Pa. Thereafter, plasma discharge is performed 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 gas from the fluorine gas introduction port 306. As a result, an aluminum compound film 102a containing an aluminum compound as a main component is formed on the substrate 101. The plasma discharge suitable for film formation is generated from the power source 311 at, for example, 5 W / cm 2 The dielectric layers 102b and 102c can be formed by applying a power of 100 W. Since known film forming methods can be used to form the dielectric layers 102b and 102c, a description thereof will be omitted.

[0024] 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 placed. In this case, it is desirable to place a shutter near the surface of each sputtering target to prevent other materials from adhering to the sputtering target surface during film formation of the other materials. In this embodiment, a form using a sputtering method, particularly a reactive sputtering method, has been described, but the aluminum compound film may also be formed by a vacuum deposition method, a thermal CVD method, a plasma CVD method, an ADL method, or the like.

[0025] (Evaluation method) Next, methods for evaluating the produced optical films will be described, including a method for evaluating the components contained in the film, a method for evaluating the optical properties of the film, and a method for evaluating environmental resistance.

[0026] The hydrogen content in the aluminum compound film 102a can be evaluated by hydrogen forward scattering spectrometry (HFS). The aluminum compound film 102a is irradiated with a high-energy ion beam (e.g., He+) on the order of MeV, and 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 the film with a high-energy ion beam on the order of MeV and then performing 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 contents of other elements in the aluminum compound film 102a can be determined.

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

[0030] The refractive index was measured using the optical thin film analysis and design software FilmWizard from Scientific Computing International. TM Here, the refractive index at a wavelength of 248 nm is calculated.

[0031] The environmental resistance was evaluated by placing the fabricated optical element 100 in an environmental tester set at a temperature of 60°C and a humidity of 80% and leaving it there for 100 hours. The evaluation atmosphere was air. The appearance before and after the environmental test was visually inspected to check whether film peeling had occurred. Regarding the evaluation criteria for environmental resistance, when the optical element was left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours and then visually inspected, if no film peeling occurred, it was rated as A. Although film peeling did not occur completely, the AlO fabricated by the method disclosed in Patent Document 1 x F y The film with significantly improved environmental resistance compared to the AlO film, i.e., the film with less peeling, was rated as B. x F y The sample showing no improvement in environmental resistance compared to the film, that is, the sample showing film peeling, was rated C.

[0032] Examples and Comparative Examples The present invention will be specifically described below with reference to examples and comparative examples. [Example 1] In Example 1, an aluminum compound film was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 20 sccm, and 20 sccm, respectively.

[0033] The aluminum content [Al] at% in the aluminum compound film produced in Example 1 was 26.6 at%, the oxygen content [O] at% was 24.5 at%, the fluorine content [F] at% was 37.0 at%, and the hydrogen content [H] at% was 11.6 at%.

[0034] This film had a small optical absorptance of 0.02% at a wavelength of 248 nm and a small refractive index of 1.489 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 35 sccm, and 20 sccm, respectively.

[0036] The aluminum content [Al] at% in the aluminum compound film produced in Example 2 was 24.4 at%, the oxygen content [O] at% was 18.9 at%, the fluorine content [F] at% was 44.4 at%, and the hydrogen content [H] at% was 11.8 at%.

[0037] This film had a low optical absorptance of 0.03% at a wavelength of 248 nm and a low refractive index of 1.458 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 45 sccm, and 2.0 sccm, respectively.

[0039] The aluminum content [Al] at% in the aluminum compound film produced in Example 3 was 28.2 at%, the oxygen content [O] at% was 17.0 at%, the fluorine content [F] at% was 51.2 at%, and the hydrogen content [H] at% was 3.6 at%.

[0040] This film had a low optical absorptance of 0.09% at a wavelength of 248 nm and a low refractive index of 1.448 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 15 sccm, and 20 sccm, respectively.

[0042] The aluminum content [Al] at% in the aluminum compound film produced in Example 4 was 26.5 at%, the oxygen content [O] at% was 26.5 at%, the fluorine content [F] at% was 32.8 at%, and the hydrogen content [H] at% was 13.8 at%.

[0043] This film had a low optical absorptance of 0.02% at a wavelength of 248 nm and a low refractive index of 1.486 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 20 sccm, and 1.0 sccm, respectively.

[0045] The aluminum content [Al] at% in the aluminum compound film produced in Example 5 was 28.3 at%, the oxygen content [O] at% was 27.3 at%, the fluorine content [F] at% was 42.5 at%, and the hydrogen content [H] at% was 1.5 at%.

[0046] This film had a low optical absorptance of 0.18% at a wavelength of 248 nm and a low refractive index of 1.483 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 30 sccm, 50 sccm, and 15 sccm, respectively.

[0048] The aluminum content [Al] at% in the aluminum compound film produced in Example 6 was 25.2 at%, the oxygen content [O] at% was 11.4 at%, the fluorine content [F] at% was 53.4 at%, and the hydrogen content [H] at% was 9.8 at%.

[0049] This film had a low optical absorptance of 0.00% at a wavelength of 248 nm and a low refractive index of 1.425 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 30 sccm, and 50 sccm, respectively.

[0051] The aluminum content [Al] at% in the aluminum compound film produced in Example 7 was 18.9 at%, the oxygen content [O] at% was 18.0 at%, the fluorine content [F] at% was 37.3 at%, and the hydrogen content [H] at% was 25.4 at%.

[0052] This film had a low optical absorptance of 0.18% at a wavelength of 248 nm and a low refractive index of 1.456 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 40 sccm, 40 sccm, and 15 sccm, respectively.

[0054] The aluminum content [Al] at% in the aluminum compound film produced in Example 8 was 28.3 at%, the oxygen content [O] at% was 24.1 at%, the fluorine content [F] at% was 28.9 at%, and the hydrogen content [H] at% was 18.3 at%.

[0055] This film had a low optical absorptance of 0.06% at a wavelength of 248 nm and a low refractive index of 1.486 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C 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 was formed to a thickness of approximately 100 nm on a quartz glass substrate using the film formation apparatus shown in Figure 2. During film formation, the flow rates of argon gas, oxygen gas, fluorine gas, and hydrogen gas introduced into the vacuum chamber 301 were 150 sccm, 50 sccm, 4.0 sccm, and 20 sccm, respectively.

[0057] The aluminum content [Al] at% in the aluminum compound film produced in Comparative Example 1 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] This film had a high light absorptance of 0.91% at a wavelength of 248 nm and a high refractive index of 1.663 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated A. The optical film of Comparative Example 1 had good environmental resistance, but its high light absorptance and refractive index made its optical properties impractical.

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

[0060] The aluminum content [Al] at% in the aluminum compound film produced in Comparative Example 2 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] This film had a low light absorptance of 0.14% at a wavelength of 248 nm, but a high refractive index of 1.571 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated A. The optical film of Comparative Example 2 had good environmental resistance, but its high refractive index made its optical properties impractical.

[0062] Comparative Example 3 In Comparative Example 3, AlO was deposited on a quartz glass substrate using the film deposition apparatus shown in FIG. x F yA film having a thickness of about 100 nm was formed. During film formation, 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. No hydrogen gas was introduced.

[0063] AlO prepared in Comparative Example 3 x F y The aluminum content [Al] at % in the film 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] This film had a low light absorptance of 0.15% at a wavelength of 248 nm, but a high refractive index of 1.553 at a wavelength of 248 nm. After being left in an environmental tester set at a temperature of 60°C and a humidity of 80% for 100 hours, the appearance was rated C, and film peeling occurred. The optical film of Comparative Example 3 had a low light absorptance, but was not practical because it had a high refractive index and poor environmental resistance.

[0065] Comparative Example 4 In Comparative Example 4, AlF was deposited on a quartz glass substrate using the film deposition apparatus shown in FIG. y H z A film having a thickness of about 100 nm was formed. During film formation, 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. No oxygen gas was introduced.

[0066] AlF prepared in Comparative Example 4 y H z The aluminum content [Al] at % in the film 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] This film had a low light absorptance of 0.05% at a wavelength of 248 nm and a low refractive index of 1.335 at a wavelength of 248 nm, but after being left for 100 hours in an environmental tester set at a temperature of 60°C and a humidity of 80%, the appearance was rated C, and film peeling occurred. The optical film of Comparative Example 4 had good optical properties but was not practical due to its low environmental resistance.

[0068] 3 summarizes the content of each element, the results of the environmental resistance evaluation, the optical absorptivity 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. Note that since the inclusion of argon in the film of each sample was confirmed, the argon content is listed in Table 1 as [Ar] at%.

[0069] 3 to 9, the conditions that aluminum, oxygen, fluorine, and hydrogen contained in the aluminum compound film (i.e., aluminum compound film) included in the optical element according to this embodiment must satisfy will be described. The inventors of the present application have found that not only the ratio (at %) of the number 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 absorptance, and refractive index.

[0070] First, we will explain the conditions for an aluminum compound film to have practically excellent environmental resistance properties. FIG. 4 is a diagram mapping the relationship between environmental resistance and the content ratio of each element, normalized so that the total of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film is 100%. Note that this diagram does not assume that the total amount of all elements contained in the aluminum compound film is 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, FIG. 4 also maps evaluation samples with different content ratios of [O], [F], and [H]. The evaluation results for environmental resistance were evaluated by evaluating the state of the film after leaving it in an environmental tester set at a temperature of 60°C and a humidity of 80%, as described above, for 100 hours.

[0071] Examples 1 to 8 were rated A or B for environmental resistance and had properties suitable for practical use, and it can be seen from Table 1 in Figure 3 that they satisfied at least one of 1 at%≦[O]at%<30at% or [Al] / [O]>3 / 2. Table 1 also shows that they satisfied [H]at%≧1at% or [F]at%≧20at%.

[0072] In particular, Examples 1 to 4 were rated A for environmental resistance, and have excellent practical properties. As can be seen from Figure 4, these are within the ranges of 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 indicates undesirable characteristics for practical use, but is within the range of [H]<1 at%. Generally, fluorine-free Al2O3 films have high environmental resistance, but environmental resistance tends to decrease when the fluorine content increases beyond a certain level. Even when a certain level of fluorine is contained, environmental resistance tends to improve when hydrogen is contained. Comparative Example 3 was presumably rated C for environmental resistance because the hydrogen content was low relative to the fluorine content. That is, when a certain level of fluorine is contained, environmental resistance is presumably reduced unless an appropriate amount of hydrogen is also contained. The exact reason for the film peeling is unclear, but it is possible that the aluminum compound film with a low hydrogen content has a reduced adhesion due to increased internal stress or a large difference in thermal expansion coefficient between the substrate and the film. Alternatively, defects may have been generated in the aluminum compound film during film formation, and leaving the aluminum compound film with defects in a moist environment may have caused moisture (i.e., OH groups) to become mixed into the film, making it brittle.

[0074] Comparative Example 4 received a rating of C for environmental resistance, indicating characteristics that are not practically desirable. However, as can be seen from Table 1, the [O] at% < 1 at% range. The exact reason for the peeling of the aluminum compound film fabricated within the range including Comparative Example 4 is unclear. However, the aluminum compound film with a low oxygen content and a high fluorine content may have reduced surface energy during film formation, resulting in reduced adhesion. Furthermore, if the base 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 act to etch the base, potentially contributing to the peeling. 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 the peeling of the coating film. This effect can also occur when fluorine is present in the film formation by evaporation or other methods. In this embodiment, a sputtering method, which involves plasma generation, is used for film formation, and active fluorine may be generated when fluorine is exposed to plasma during film formation. It is possible that the active fluorine has a strong effect of etching the underlayer, contributing to the occurrence of film peeling. In this embodiment, it can also be considered that the presence of oxygen in the aluminum compound film suppresses film peeling caused by fluorine. Therefore, when a film formation method (sputtering method) involving plasma generation is used on an underlayer that can be etched by fluorine (fluorine compound), the aluminum compound film configuration of this embodiment is suitable.

[0075] In this regard, the aluminum compound films produced in the range including Examples 1 to 8, and particularly in the range including Examples 1 to 4, may have suppressed internal stress and the difference in thermal expansion coefficient between the substrate and the layer because the amounts and ratios of the elements oxygen, hydrogen, and fluorine contained therein are appropriate. Also, the inclusion of an appropriate amount of hydrogen reduces film defects formed during film formation, making it difficult for moisture (i.e., OH groups) to be mixed in from the outside, and the surface energy during film formation is sufficiently large, which may have made film peeling less likely to occur.

[0076] Next, conditions for an aluminum compound film to have practically excellent optical absorptance properties will be described. Fig. 5 is a diagram mapping the relationship between the magnitude of optical absorptance and the content ratio of each element, normalized so that the total of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film is 100%. Note that this diagram does not assume that the total amount of all elements contained in the aluminum compound film is 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Fig. 5 also maps evaluation samples with different content ratios of [O], [F], and [H].

[0077] Examples 1 to 8 have optical absorptance of 0.2% or less at a wavelength of 248 nm, providing practically suitable properties. 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 rephrased as [O] / ([O]+[H]+[F])≦0.5. Furthermore, according to Table 1 in FIG. 3, these examples fall within the range of [F]≧1 at%.

[0078] In particular, Examples 1 to 4, 6, and 8 have optical absorptances of 0.1% or less at a wavelength of 248 nm, providing excellent practical properties. These are within the ranges of 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 exhibited a light absorptance at a wavelength of 248 nm exceeding 0.2%, which is unsuitable for practical use. However, it is within the ranges of [F] / ([O] + [F] + [H]) < 0.2 and ([F] + [H]) / ([O] + [F] + [H]) < 0.5. The latter can also be rephrased as [O] / ([O] + [H] + [F]) ≥ 0.5. The exact reason for the high light absorptance of the aluminum compound film layer fabricated within the range including Comparative Example 1 is unclear. However, it is possible that the low fluorine content relative to the oxygen content resulted in significant material-specific light absorption within the wavelength range used. Furthermore, it is possible that the low hydrogen content resulted in insufficient compensation for layer defects generated during the deposition of the aluminum compound film.

[0080] In this regard, the aluminum compound films fabricated in the range including Examples 1 to 8, particularly the range including Examples 1 to 4, 6, and 8, have a high fluorine content relative to the oxygen content. This may have resulted in a shift to the shorter wavelength side of the wavelength band where significant material-specific light absorption occurs, and light absorption no longer occurs within the wavelength range used. Furthermore, the addition of an appropriate amount of hydrogen may have compensated for defects in the aluminum compound film, thereby reducing light absorption.

[0081] FIG. 6 shows the results of measuring the light absorptance spectra of Example 1 and Comparative Example 1 in the ultraviolet wavelength range of 180 nm to 280 nm. Example 1 had significantly lower light absorptance than Comparative Example 1 over the entire measurement range.

[0082] Next, the conditions for an aluminum compound film to have practically excellent properties with respect to refractive index will be described. Fig. 7 is a diagram mapping the relationship between the magnitude of refractive index and the content ratio of each element, normalized so that the total of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film is 100%. Note that this diagram does not assume that the total amount of all elements contained in the aluminum compound film is 100%. In addition to the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 4, Fig. 7 also maps evaluation samples with different content ratios of [O], [F], and [H].

[0083] FIG. 8 shows the relationship between the value of ([F]+[H]) / ([O]+[F]+[H]) and the refractive index. From FIG. 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, and that the materials have properties suitable for practical use. From FIG. 7, it can be seen that these Examples are within the range of ([F]+[H]) / ([O]+[F]+[H])≧0.5. Furthermore, from Table 1 in FIG. 3, it can be seen that these Examples are within the range of [O]<30 at %.

[0084] 8, it can be seen that in the range including Comparative Examples 1 to 3, the refractive index at a wavelength of 248 nm exceeds 1.53, and the properties are not suitable for practical use. As can be seen from FIG. 7, these Comparative Examples are included in the range ([F] + [H]) / ([O] + [F] + [H]) < 0.5. 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 an appropriately low refractive index. In addition, the high hydrogen content may have caused some of the hydrogen to penetrate between the lattices, reducing the film density and resulting in a low refractive index.

[0086] (Overall practical characteristics) Based on the above-described results of the investigation into environmental resistance, light absorption, and refractive index, the conditions for an aluminum compound film to have all three properties at levels suitable for practical use, i.e., to have comprehensive practical properties, are described. Figure 9 is a diagram mapping the relationship between the level of comprehensive practical properties and the content ratio of each element, normalized so that the total of [O] at%, [F] at%, and [H] at% contained in the aluminum compound film is 100%. Note that this diagram does not represent the total amount of all elements contained in the aluminum compound film as 100%. In addition to the above-described 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 levels of comprehensive practical properties are shown in three levels: unsuitable for practical use, suitable for practical use, and excellent for practical use. The unsuitable for practical use level means that at least one of the three properties is not practical. The suitable for practical use level means that all three properties satisfy practical requirements. A level of excellent practicality means that all three properties satisfy the practical requirements and at least one property is at a level excellent for practical use.

[0087] Examples 1 to 8 satisfy at least the practical requirements for all three properties, and it can be seen from Figure 9 and Table 1 in Figure 3 that these are films that satisfy all of [Film Composition 1] to [Film Composition 4] described below.

[0088] [Film composition 1] At least one of the following conditions is satisfied: the oxygen content [O]at% is 1at% or more and less than 30at%; or [Al] / [O]>3 / 2. That is, at least one of 1 at %≦[O]at %<30 at % and [Al] / [O]>2 / 3 is satisfied.

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

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

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

[0092] Furthermore, it can be seen from FIG. 9 and Table 1 in FIG. 3 that it is more preferable to satisfy at least one of [Film Composition 5] to [Film Composition 16] described below.

[0093] [Film composition 5] 10at%≦[Al]at%≦40at%

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

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

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

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

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

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

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

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

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

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

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

[0105] [Example 9] Next, Example 9 shows a transmissive optical element provided with an anti-reflection structure that is a multilayer optical structure including the aluminum compound film of Example 1. As shown in Fig. 1, an aluminum compound film 202a similar to that shown in Example 1 was laminated on a quartz glass substrate 101, and low refractive index layers 202b and high refractive index layers 202c were alternately stacked on the aluminum compound film 202a, for a total of five layers, to form an optical structure 102.

[0106] Magnesium fluoride (MgF2) was used for the low refractive index layer 202b, and samarium fluoride (SmF3) was used for the high refractive index layer 202c. In consideration of the intended use of the optical element 100, it was decided to maximize the transmittance 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. Note that, although it is desirable to make the film thickness of the aluminum compound film 202a as small as possible to improve the transmittance characteristics, the film thickness was set to 10 nm to ensure sufficient environmental resistance.

[0107] 10(a) shows Table 2, which lists the material of each layer in this example, the refractive index at a wavelength of 248 nm, and the physical film thickness. In the transmittance-type optical element of this example, the transmittance for light with a wavelength of 248 nm was 99.8% at a light incident angle of 10 degrees, and the anti-reflection function was very good.

[0108] Comparative Example 5 Comparative Example 5 shows a transmissive optical element in which a multilayer optical structure including the aluminum compound film of Comparative Example 1 is provided as an anti-reflection 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 low-refractive index layers and high-refractive index layers were stacked alternately on top of the aluminum compound film to form an 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] 10(b) shows Table 3, which summarizes the material of each layer of 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 with a wavelength of 248 nm was 99.0% or less at a light incident angle of 10 degrees. It can be assumed that the aluminum compound layer of Comparative Example 1 absorbs a large amount of light due to its high light absorption rate, and that the high refractive index makes the anti-reflection performance of the optical structure insufficient, resulting in the reduced transmittance of the optical element of this comparative example.

[0110] 11 shows the wavelength characteristics of transmittance for the transmissive optical elements of Example 9 and Comparative Example 5. It was confirmed that Example 9 had good transmittance characteristics in a wavelength band of at least ±20 nm centered on a wavelength of 248 nm, and had an extremely high antireflection function compared to Comparative Example 5.

[0111] [Example 10] Example 10 shows a transmissive optical element provided with an anti-reflection structure that is a multilayer optical structure including the aluminum compound film of Example 1. As shown in Fig. 1, an aluminum compound film 202a similar to that shown in Example 1 was laminated on a quartz glass substrate 101, and low refractive index layers 202b and high refractive index layers 202c were alternately stacked on the aluminum compound film 202a, for a total of five layers, to form an optical structure 102.

[0112] Magnesium fluoride (MgF2) was used for the low refractive index layer 202b, and samarium fluoride (SmF3) was used for the high refractive index layer. In consideration of the intended use of the optical element 100, it was decided to maximize the transmittance 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. Regarding the aluminum compound film 202a, although it is desirable to make the film thickness as small as possible to improve the transmittance characteristics, the film thickness was set to 10 nm to ensure sufficient environmental resistance.

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

[0114] Comparative Example 6 Comparative Example 6 shows a transmissive optical element in which a multilayer optical structure including the aluminum compound film of Comparative Example 1 is provided as an anti-reflection structure. An aluminum compound film similar to that shown in Comparative Example 1 was laminated on a quartz glass substrate, and low-refractive index layers and high-refractive index layers were alternately stacked on top of the aluminum compound film, for a total of five layers, 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 of this comparative example, their refractive indices at a wavelength of 193 nm, and their physical film thicknesses. In the transmittance-type optical element of this comparative example, the transmittance for light with a wavelength of 193 nm was 98.0% or less at a light incident angle of 10 degrees. It can be assumed that the aluminum compound film of Comparative Example 1 absorbs a large amount of light due to its high light absorption rate, and its high refractive index results in insufficient anti-reflection performance of the optical structure, resulting in reduced transmittance for the optical element of this comparative example. Furthermore, in this comparative example, the wavelength of the target light is short at 193 nm, so the influence of light absorption is greater than for a wavelength of 248 nm, resulting in worse transmittance characteristics than in Comparative Example 5, in which the wavelength of the target light was 248 nm.

[0116] 13 shows the wavelength characteristics of transmittance for the transmissive optical elements of Example 10 and Comparative Example 6. It was confirmed that Example 10 had good transmittance characteristics in a wavelength band of at least ±10 nm centered on a wavelength of 193 nm, and had an extremely high antireflection 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, but the target light handled by the optical element according to the present embodiments is of course 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 low-refractive-index layers and high-refractive-index layers, and the physical film thickness of each layer in accordance with the light source used and the intended use of the optical element.

[0118] [Embodiment 2] As the second embodiment, an optical device including the optical element described in the first embodiment will be described. The optical element described in the first embodiment can be applied to various optical devices, such as camera lenses, telescopes, projectors, exposure apparatuses, and measuring instruments. In particular, the optical element 100 of the first embodiment can be suitably applied to optical devices equipped with a light source, such as projectors, exposure apparatuses, and measuring instruments. This is because the transmission characteristics 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. However, if the optical element has a property that can suppress absorption of ultraviolet light as in the above-described examples, it can be particularly suitably implemented in devices whose light source is ultraviolet light.

[0119] 14 is a schematic diagram of an exposure apparatus 200 as an example of an optical apparatus according to the second embodiment. The exposure apparatus 200 includes a light source 201, mirrors 202 and 203 that constitute an illumination optical system, a reticle stage 205 as a support for supporting a reticle 204, a projection optical system 206 that projects the pattern of the reticle 204, and a substrate stage 208 that mounts a substrate 207. The mirrors 202 and 203 of the illumination optical system are optical elements according to the first embodiment, and are formed by depositing an aluminum compound film (AlO x F y H z A multilayer film including a reflective film is formed as an optical structure (reflective film).

[0120] A photoresist is applied to the substrate 207, and the photoresist is exposed by the exposure light 209. The substrate 207 may be a semiconductor wafer (semiconductor substrate) or a glass substrate for an FPD (flat panel display). The exposure light of the exposure apparatus 200 is typically ultraviolet light. The wavelength of the exposure light is, for example, 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, but is not particularly limited thereto. Alternatively, the wavelength is about 157 nm for an F2 excimer laser light source, and 10 to 20 nm for an EUV (extreme ultraviolet) light source.

[0121] In this embodiment, an example has been shown in which the optical element according to embodiment 1 is applied to mirrors 202 and 203 of an illumination optical system. However, the application is not particularly limited, and the optical element according to embodiment 1 may be applied to a lens of a projection optical system, for example. Furthermore, the projection optical system may be configured with a mirror, and the optical element according to embodiment 1 may be applied to the mirror. The projection optical system may be a reduced projection type, a life-size projection type, or an enlarged projection type. While a transmissive reticle is exemplified as the reticle 204 here, a reflective reticle may also be used. The projection optical system may be a refractive type using a lens, or a reflective type using a mirror. The optical element according to embodiment 1 may be applied to a mirror of a reflective reduced projection optical system provided in an exposure apparatus equipped with an EUV light source.

[0122] In recent years, there have been studies on improving the production capacity of exposure equipment. For example, an aluminum compound film (AlO) with low light absorption at wavelengths of 300 nm or less has been developed for an exposure equipment equipped with a KrF excimer laser light source. x F y H z When using a thin film, if the environmental resistance can be improved, it becomes possible to prevent deterioration of optical performance over time. By applying the optical element according to embodiment 1, it becomes possible to maintain high throughput even when used for a long period of time, and an exposure apparatus with high productivity can be realized.

[0123] [Other embodiments] The present invention is not limited to the above-described embodiments and examples, and many modifications are possible within the technical spirit of the present invention. For example, the above-described different embodiments and examples may be combined in whole or in part.

[0124] In the above description of the embodiment, optical elements such as lenses, mirrors, prisms, and optical filters are given as examples of elements having an aluminum compound film, but the elements in which the present invention is embodied are not limited to optical elements. The present invention can be embodied in elements for various applications such as image pickup elements, 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 pickup element or semiconductor element, for example, in a CMOS sensor or CCD sensor, the above-mentioned aluminum compound film (AlO x F y H z Furthermore, in the case of a display element or a light-emitting element, for example, an OLED (Organic Light Emitting Diode) element can be used. As a protective film for the display pixel or the light-emitting portion, the above-mentioned aluminum compound film (AlO x F y H zExamples of exterior components or mechanical elements include housings and mechanical components for automobiles or other devices that are formed by hot pressing aluminum-based plated steel sheets. The above-mentioned aluminum compound film (AlO x F y H z By providing an aluminum compound film (AlO x F y H z The environment in which the element provided with the film is used is not limited to the atmospheric environment, but may be a vacuum environment or a gas atmosphere environment other than the atmospheric environment.

[0125] In the above explanation, the aluminum compound film (AlO x F y H z Optical devices such as camera lenses, telescopes, projectors, exposure devices, and measuring instruments have been cited as examples of devices equipped with elements provided with a film, and exposure devices have been specifically described in particular. However, devices to which the present invention can be embodied are not limited to optical devices. For example, the present invention can be suitably implemented in various devices by incorporating the optical elements, imaging devices, display devices, light-emitting devices, mechanical elements, etc. described above into communication devices such as smartphones, and mobile or transport devices such as automobiles and drones.

[0126] Furthermore, if the specification contains a statement that "A is B," for example, it can be said that the specification discloses that "A is not B," even if the statement that "A is not B" is omitted. This is because when a statement that "A is B" is made, it is assumed that the case in which "A is not B" is taken into consideration.

[0127] This specification discloses at least the following configurations. [Configuration 1] A device comprising a substrate and a structure provided on the substrate, the 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 is satisfied. A device characterized by: [Configuration 2] 10at%≦[Al]at%≦40at%, 2. The element according to configuration 1. [Configuration 3] [Al]at%≧[O]at% is satisfied; 3. The element according to configuration 1 or 2. [Configuration 4] [H] / ([O]+[F]+[H])≦0.5 is satisfied; 4. The element according to any one of configurations 1 to 3. [Configuration 5] [F]at%≧1at% is satisfied, 5. The element according to any one of configurations 1 to 4. [Configuration 6] [F] / ([O]+[F]+[H])≧0.2 6. The element according to any one of configurations 1 to 5. [Configuration 7] [F]at%≦60at% is satisfied, 7. The element according to any one of configurations 1 to 6. [Configuration 8] [H]at%≧1at% is satisfied, 8. The element according to any one of configurations 1 to 7. [Configuration 9] [H]at%≦30at% is satisfied, 9. The element according to any one of configurations 1 to 8. [Configuration 10] [O]at%≧10at% is satisfied, 10. The element according to any one of configurations 1 to 9. [Configuration 11] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar] at %, [Ar]at%≧0.1at% is satisfied, 11. The element according to any one of configurations 1 to 10. [Configuration 12] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar] at %, [Ar]at%≦5at% is satisfied, 12. The element according to any one of configurations 1 to 11. [Configuration 13] When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar] at %, [Ar]at%<[H]at% is satisfied. 13. The element according to any one of configurations 1 to 12. [Configuration 14] The structure is an optical structure. 14. The element according to any one of configurations 1 to 13. [Configuration 15] The optical structure has an anti-reflection structure. 15. The device of claim 14. [Configuration 16] The optical structure has a reflective structure. 15. The device of claim 14. [Configuration 17] the optical structure includes a low refractive index layer and a high refractive index layer stacked on the aluminum compound film; 17. The device according to any one of configurations 14 to 16. [Configuration 18] The aluminum compound film has a refractive index of 1.53 or less for light with a wavelength of 248 nm. 18. The device according to any one of configurations 1 to 17. [Configuration 19] The aluminum compound film has a light absorptance of 0.2% or less for light with a wavelength of 248 nm. 19. The device according to any one of configurations 1 to 18. [Configuration 20] The substrate is a substrate of an optical element. 20. The device according to any one of configurations 1 to 19. [Configuration 21] The optical element is any one of a lens, a mirror, a prism, and an optical filter. 21. The device of claim 20. [Configuration 22] The element according to any one of configurations 1 to 21, a support for supporting the element; Equipment with. [Configuration 23] a light source, an illumination optical system that guides light emitted by the light source to a reticle, and a projection optical system that projects a pattern of the reticle onto a substrate; At least one of the illumination optical system and the projection optical system includes the element according to any one of structures 1 to 21. An optical instrument characterized by: [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 formation equipment / 301···Vacuum chamber / 302···Exhaust system / 303···Argon gas inlet port / 304···Oxygen gas inlet port / 305···Hydrogen gas inlet port / 306···Fluorine gas inlet port / 307···Sputtering target / 308···Backing plate / 309···Magnetic mechanism / 310···Substrate holding mechanism / 311···Power supply

Claims

1. A device comprising a substrate and a structure provided on the substrate, the 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 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 is satisfied. A device characterized by:

2. 10 at%≦[Al] at%≦40 at%, 2. The device according to claim 1 .

3. [Al] at% ≧ [O] at% is satisfied; 2. The device according to claim 1 .

4. [H] / ([O]+[F]+[H])≦0.5 is satisfied; 2. The device according to claim 1 .

5. [F] at% ≧ 1 at%, 2. The device according to claim 1 .

6. [F] / ([O]+[F]+[H])≧0.2 2. The device according to claim 1 .

7. [F] at%≦60 at%, 2. The device according to claim 1 .

8. [H] at% ≧ 1 at% is satisfied; 2. The device according to claim 1 .

9. [H] at%≦30 at%, 2. The device according to claim 1 .

10. [O] at% ≧ 10 at%, 2. The device according to claim 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% is satisfied; 2. The device according to claim 1 .

12. When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar] at %, [Ar] at%≦5 at% is satisfied; 2. The device according to claim 1 .

13. When the atomic concentration of argon relative to all elements in the aluminum compound film is [Ar] at %, [Ar] at% < [H] at% is satisfied; 2. The device according to claim 1 .

14. The structure is an optical structure.

14. A device according to any one of claims 1 to 13.

15. The optical structure has an anti-reflection structure.

15. The device of claim 14.

16. The optical structure has a reflective structure.

15. The device of claim 14.

17. the optical structure includes a low refractive index layer and a high refractive index layer stacked on the aluminum compound film; 15. The device of claim 14.

18. the aluminum compound film has a refractive index of 1.53 or less for light with a wavelength of 248 nm; 14. A device according to any one of claims 1 to 13.

19. the aluminum compound film has a light absorptance of 0.2% or less for light with a wavelength of 248 nm; 14. A device according to any one of claims 1 to 13.

20. The substrate is a substrate of an optical element.

14. A device according to any one of claims 1 to 13.

21. The optical element is any one of a lens, a mirror, a prism, and an optical filter.

21. The device of claim 20.

22. A device according to any one of claims 1 to 13; a support for supporting the element; Equipment with.

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

Images