JP2021124690A - Optical device, article manufacturing method, and optical member manufacturing method - Google Patents

Abstract

To provide a technique advantageous for solving problems caused by the reduced intensity of light reaching an illuminated surface.SOLUTION: An exposure device includes: a light source that emits light that has a continuous wavelength range; and at least one optical element provided with an optical film including a photocatalytic film. The exposure device is configured so that light emitted from the light source is incident on an irradiated surface via at least one optical element. The lower limit wavelength in the wavelength range of light emitted from the light source and incident on an irradiated surface via at least one optical element is determined by the light absorption characteristics of the photocatalytic film.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical device, an article manufacturing method, and an optical member manufacturing method.

In an exposure apparatus provided with an optical element such as a lens or a mirror, the optical performance (transmittance or reflectance) deteriorates due to the accumulation of contaminants on the surface of the optical element due to irradiation with ultraviolet light. Patent Document 1 describes an optical member in which a photocatalytic film made of a photocatalytic substance and having a thickness of 5 Å or more and 50 Å or less is provided on a quartz glass substrate. In Patent Document 2, low refractive index layers and high refractive index layers are alternately laminated, the uppermost layer is composed of a low refractive index layer, and at least the high refractive index layer immediately below the uppermost layer is a metal oxide having photocatalytic activity. A multilayer antireflection film composed of layers is described. Patent Document 3 describes an antireflection film having a low refractive index transparent film on the outermost surface and a high refractive index transparent film provided under the low refractive index transparent film.

Japanese Unexamined Patent Publication No. 2005-345812 Japanese Unexamined Patent Publication No. 2000-329904 Japanese Unexamined Patent Publication No. 2008-003390

When an optical film including a photocatalyst film is provided on the surface of an optical element in an optical device such as an exposure device, light is absorbed by the photocatalyst film, and the intensity of light incident on the irradiated surface may decrease.

An object of the present invention is to provide an advantageous technique for solving a problem caused by a decrease in the intensity of light reaching an irradiated surface.

One aspect of the present invention relates to an optical device, which comprises a light source that emits light having a continuous wavelength range and at least one optical element provided with an optical film including a photocatalyst film. An optical device in which light emitted from the light source is incident on an irradiated surface via the at least one optical element, and is emitted from the light source and incident on the irradiated surface via the at least one optical element. The lower limit wavelength of the optical wavelength range is determined by the light absorption characteristics of the photocatalyst film.

The present invention provides an advantageous technique for solving a problem caused by a decrease in the intensity of light reaching an irradiated surface.

The figure which shows the structure of the optical apparatus of 1st to 4th Embodiment. The figure which illustrates the emission wavelength of the mercury lamp of a light source part. The figure which exemplifies the spectral transmittance of the antireflection film for one surface. The figure which exemplifies the spectral transmittance of the antireflection film for 40 surfaces. The figure which shows the structure of the 1st to 4th antireflection film (optical film) or an optical member. The figure which standardized the spectral characteristic of the exposure light in the exposure apparatus when the _{HfO 2} film was used as a photocatalyst. The figure which standardized the spectral characteristic of the exposure light in the exposure apparatus when the _{Ta 2} O ₅ film was used as a photocatalyst. The figure which standardized the spectral characteristic of the exposure light in the exposure apparatus when the _{TiO 2} film was used as a photocatalyst. The figure which standardized the spectral characteristic of the exposure light (light incident on the photosensitive material on a substrate) in a conventional exposure apparatus.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiment, not all of the plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the attached drawings, the same or similar configurations are given the same reference numbers, and duplicate explanations are omitted.

FIG. 1 schematically shows the configuration of the optical device 100 of the first embodiment. The optical device 100 is, for example, an exposure device or a component thereof (for example, an illumination optical system, a projection optical system, etc.) that exposes the photosensitive material so that the pattern of the original plate is transferred to the photosensitive material (photoresist) on the substrate. Can be configured as. Here, in order to present a more specific example, an example in which the optical device 100 is configured as an exposure device will be described.

The optical device 100 configured as an exposure device may include a plurality of blocks such as a light source unit 1, an illumination optical system 2, a projection optical system 3, an original plate stage unit 4, and a substrate stage unit 5. A seal glass 6 (seal window) may be arranged at the boundary between blocks adjacent to each other among the plurality of blocks. The sealing glass 6 is typically an optical element that does not have optical power. Here, the expression seal glass 6 is used to describe all or at least one of the seal glasses 61, 62, 63, 64.

A seal glass 61 is arranged at the boundary between the light source unit 1 and the illumination optical system 2 to separate the light source unit 1 and the illumination optical system 2. A seal glass 62 is arranged at the boundary between the illumination optical system 2 and the original plate stage portion 4, and the illumination optical system 2 and the original plate stage portion 4 are separated by the seal glass 62. A seal glass 63 is arranged at the boundary between the original plate stage portion 4 and the projection optical system 3, and the original plate stage portion 4 and the projection optical system 3 are separated by the seal glass 63. A seal glass 64 is arranged at the boundary between the projection optical system 3 and the substrate stage portion 5, and the projection optical system 3 and the substrate stage portion 5 are separated by the seal glass 64. The plurality of components constituting the light source unit 1 may be arranged in one open or closed space.

The plurality of components constituting the illumination optical system 2 may be arranged in one open or closed space. The plurality of parts constituting the original stage portion 4 may be arranged in one open or closed space. The plurality of components constituting the projection optical system 3 may be arranged in one open or closed space. The plurality of components constituting the board stage portion 5 may be arranged in one open or closed space.

The light source unit 1 may include, for example, a mercury lamp 101 and an elliptical mirror 102. The mercury lamp 101 is an example of a light source that emits light having a continuous wavelength range. The illumination optical system 2 may include, for example, a mirror 201, a lens 203, a fly eye lens 204, a lens 205, a mirror 206, a slit member 207, and a lens (imaging optical system) 208. The projection optical system 3 may include, for example, a mirror 301, a concave mirror 302, a convex mirror 303, and a mirror 304. The original plate stage unit 4 may include an original plate stage 42 that holds the original plate 41 and an original plate stage drive mechanism (not shown) that drives the original plate stage 42. The substrate stage portion 5 may include a substrate stage 52 that holds the substrate 51 and a substrate stage drive mechanism (not shown) that drives the substrate stage 52.

The light emitted from the mercury lamp 101 of the light source unit 1 is reflected by the elliptical mirror 102, passes through the sealing glass 61, is reflected by the mirror 201, and is focused on the second focal plane 202 of the elliptical mirror 102. The light focused on the second focal plane 202 passes through the lens 203, enters the incident surface of the fly's eye lens 204, exits from the ejection surface of the fly's eye lens 204, passes through the lens 205, and is reflected by the mirror 206. The surface on which the slit member 207 is arranged is illuminated by Koehler. The slit member 207 has a slit opening, and the light incident on the surface on which the slit member 207 is arranged passes through the slit opening and further passes through the lens 208 and the seal glass 62 to critically illuminate the original plate 41.

The light that illuminates the original plate 41 is diffracted by the original plate 41. The light diffracted by the original plate 41 passes through the seal glass 63, is reflected by the mirror 301, the concave mirror 302, and the convex mirror 303, is further reflected by the concave mirror 302, the mirror 304, passes through the seal glass 64, and is on the substrate 51. An image is formed on the photosensitive material. The original plate stage 42 holding the original plate 41 and the substrate stage 52 holding the substrate 51 are scanned and driven in a direction parallel to the Y direction in FIG. As a result, the pattern of the original plate 41 is transferred as a latent image to the photosensitive material on the substrate 51. The latent image is converted into a physical pattern through a developing process. All or part of the members arranged in the optical path between the mercury lamp 101 (light source) and the substrate 51 are also referred to as optical elements or optical members in this specification.

FIG. 9 shows the spectral characteristics of light used for exposing a substrate (photosensitive material) in a conventional exposure apparatus. In the conventional exposure apparatus, light in the wavelength range of 340 nm to 450 nm including the emission line spectra of the i-line, h-line, and g-line of the mercury lamp is used as the exposure light. In the manufacture of devices such as display devices, it is advantageous to widen the wavelength range of the exposure light to the short wavelength side in order to increase the resolution of the exposure apparatus in order to meet the demand for high definition. For example, when a novolak type resist is used as the photosensitive material (photoresist), the wavelength on the short wavelength side of the wavelength range of the light (that is, the exposure light) incident on the novolak type resist, that is, the wavelength range, is adjusted according to the sensitivity characteristics. It is useful to set the lower limit wavelength to 290 nm.

However, when the lower limit wavelength of the wavelength range of the exposure light in the exposure apparatus is set to 290 nm, the light of 290 nm to 340 nm, which has not been used in the past, promotes the deposition of contaminants by the photochemical reaction on the surface of the optical element in the exposure apparatus. Will be done. Therefore, a technique for preventing the accumulation of pollutants on the surface of the optical element is required.

FIG. 2 shows standardized spectral characteristics of the light generated by the mercury lamp 101 when the mercury lamp 101 of the light source unit 1 of FIG. 1 is of the Deep UV type. The lower limit wavelength of the wavelength range of the light generated by the mercury lamp 101 is 240 nm, which is shorter than the lower limit wavelength of 290 nm in the wavelength range of the exposure light.

3 and 4 show the spectral characteristics of the antireflection film (optical film) provided in the optical element when the antireflection film (optical film) includes a photocatalytic film. 3 and 4 show the spectral transmittances of the antireflection film when the _{HfO 2} film, the Ta ₂ O ₅ film, and the TiO _{2 film are used as the photocatalyst film.} FIG. 3 shows the spectral transmittance of one antireflection film. FIG. 4 shows the spectral transmittances of the antireflection films for 40 surfaces. The spectral transmittance of the antireflection film for 40 surfaces can correspond to the spectral transmittance of the entire optical device 100, that is, in the optical path from the mercury lamp 101 to the substrate 51. The 40 planes can be two planes of each of the 20 optics. Dashed 81,801 is photocatalyst film indicates the spectral transmittance of the antireflection film when it is HfO ₂ film. The solid lines 82 and 802 show the spectral transmittance of the antireflection film when the _{photocatalyst film is a Ta 2} O _{5 film.} The broken lines 83 and 803 show the spectral transmittance of the antireflection film when the _{photocatalyst film is a TiO 2 film.} As shown in FIG. 4, the _{antireflection film using the HfO 2} film as the photocatalytic film absorbs light of 260 nm or less. _{An antireflection film using a Ta 2} O ₅ film as a photocatalyst film absorbs light of 320 nm or less. _{An antireflection film using a TiO 2} film as a photocatalyst film absorbs light of 410 nm or less.

6 and 7 and 8 show _{an exposure apparatus using an antireflection film using an HfO 2} film, an antireflection film using a Ta ₂ O ₅ film, and an antireflection film using a TiO ₂ film, respectively. The spectral characteristics of the exposure light (light incident on the photosensitive material on the substrate 51) are standardized and shown. _{In the case of the antireflection film using the HfO 2} film shown in FIG. 6, the lower limit wavelength of the wavelength range of the exposure light in the exposure apparatus is 240 nm, and the Deep UV type mercury lamp 101 has the lower limit of the wavelength range of the generated light. Same as wavelength. From this fact, the anti-reflection film using HfO ₂ has less light absorption in the anti-reflection film using HfO _2, it is found the expression of photocatalytic activity by light absorption is very weak. The present inventor has confirmed through experiments that pollutants are deposited on the optical element by a photochemical reaction because the photocatalytic activity due to light absorption is extremely weak on the surface of the antireflection film using the _{HfO 2 film.}

_{In the case of the antireflection film using the Ta 2} O ₅ film shown in FIG. 7, the lower limit wavelength of the exposure light in the optical device 100 as the exposure device is 290 nm, which is suitable for the sensitivity characteristics of the novolak resist. You can see that there is. The present inventor _{has confirmed through experiments that photocatalytic activity due to light absorption is exhibited on the surface of the antireflection film using the Ta 2} O ₅ film, and that no contaminants are deposited on the optical element due to the photochemical reaction. When a novolak type resist is used, if the lower limit wavelength of the exposure light in the optical device 100 is 290 nm, the light having a wavelength less than 290 nm is absorbed by the photocatalyst film and contaminates the optical element (optical member). Prevents material buildup. Further, light having a wavelength of 290 nm or more contributes to the photosensitivity of the novolak resist. The antireflection film having a photocatalytic film has a high transmittance for light having a wavelength that contributes to the photosensitivity of the novolak resist. Therefore, this embodiment is advantageous for solving the problem caused by the decrease in the intensity of the light reaching the irradiated surface.

The novolak resist has photosensitivity at 290 nm, which is the lower limit of the wavelength range of the exposure light. Alternatively, the novolak type resist has 10% or more, 20% or more, 30% or more, or 40% or more, or 40% or more of the maximum sensitivity of the resist at 290 nm, which is the lower limit wavelength of the wavelength range of the exposure light. It can have a sensitivity of 50% or more.

_{In the case of the antireflection film using the TiO 2} film shown in FIG. 8, the lower limit wavelength of the exposure light wavelength range in the exposure apparatus is 370 nm, which is the lower limit wavelength of the exposure light wavelength range in the conventional exposure apparatus. It can be seen that the wavelength is longer than 340 nm. From this, it can be seen that the antireflection film using the _{TiO 2} film is not suitable for the purpose of shortening the lower limit wavelength of the wavelength range of the exposure light in the exposure apparatus according to the sensitivity characteristics of the novolak resist.

FIG. 5 schematically shows the structure of the antireflection film (optical film) 7 or the optical member 70 of the present embodiment. The optical member 70 includes an optical element 700 and an antireflection film 7 arranged on the optical element 700. The layer structure of the antireflection film 7 is not particularly limited, but in the example of FIG. 5, the antireflection film 7 has a high refractive index layer 704, a low refractive index layer 703, and a high refractive index arranged on the optical element 700. It has four layers, a rate layer 702 and a low refractive index layer 701. The low refractive index layer 701 is the uppermost layer of the antireflection film 7, that is, a layer exposed to space. The high-refractive index layer 702 is a high-refractive index layer directly below the uppermost layer, and is composed of a photocatalytic film. The antireflection film 7 has a high refractive index layer in which the uppermost layer is composed of a low refractive index layer 701 and the layer immediately below the uppermost layer is a photocatalyst film in order to suppress the reflection of light by the optical member 70 to a low level over a wide wavelength range. It is advantageous to be composed of 702.

In one configuration example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is _{composed of a Ta 2} O ₅ film, and has a low refractive index. The layer 701 is _{composed of a SiO 2} film, and the lower limit of the wavelength range of the exposure light is 290 nm. _{The Ta 2} O ₅ film as the high refractive index layer 702 functions as a photocatalytic film. The high refractive index layer 704 is photocatalytic activity of the HfO ₂ film is very low, it does not function the HfO ₂ film as a photocatalyst film. _{The SiO 2} film as the low refractive index layer 701 is the uppermost layer. _{From another point of view, the SiO 2} film as the low refractive index layer 701 is a surface film that covers _{the Ta 2} O ₅ film as the photocatalytic film.

The optical device 100 includes at least one optical element provided with a reflection anti-vibration film (optical film) 7 including a photocatalyst film, and light emitted from a light source is applied to an irradiated surface via the at least one optical element. It can be understood as an example of an incident optical device. In the optical device 100, the lower limit wavelength of the wavelength range of the light emitted from the light source and incident on the irradiated surface via the at least one optical element is determined by the light absorption characteristics of the photocatalyst film. The antireflection film 7 may be arranged on one or two surfaces of at least one light transmissive optical element arranged in the optical path between the light source and the substrate.

Even if all or part of the mirrors such as the elliptical mirror 102, the mirror 201, the mirror 206, the mirror 301, the concave mirror 302, the convex mirror 303, and the mirror 304 are provided with a reflection increasing film (optical film) including a photocatalytic film. good. The photocatalyst film contained in the antireflection film described above can be applied to the photocatalyst film contained in the reflection increasing film. The antireflection film including the photocatalyst film may be provided on an optical element such as a bandpass filter or an ND filter.

Hereinafter, the second embodiment will be described. Matters not mentioned as the first embodiment may follow the first embodiment. Of the plurality of optical elements constituting the optical device 100, the farther the optical element is from the mercury lamp 101, which is the light source, the less light is absorbed by the photocatalytic film of the antireflection film, and the photocatalytic activity becomes weaker. In the second embodiment, the optical element provided with the antireflection film including the photocatalytic film is limited.

First, the cleanliness of air in the five spaces in which the light source unit 1, the illumination optical system 2, the projection optical system 3, the original plate stage unit 4 and the substrate stage unit 5 are arranged will be described. Since the light source unit 1 requires a large amount of air for cooling the mercury lamp 101, normally, the air in the clean room is directly drawn into the space where a plurality of parts constituting the light source unit 1 are arranged. Can be used as cooling air. Therefore, more pollutants are present in the space of the light source unit 1 than in the other four spaces. For example, chemical pollutants contained in the outside air, chemical pollutants caused by process materials used in manufacturing equipment, chemical pollutants contained in operator sweat, exhaled breath, etc., chemical pollutants emitted from the inner wall of a clean room, etc. are light sources. There is a possibility of being drawn into the space of part 1.

As for the illumination optical system 2 and the projection optical system 3, since it is easy to maintain a plurality of components constituting them in a closed closed space, the space of the illumination optical system 2 and the space of the projection optical system 3 are , It is possible to keep the cleanliness of the space the highest compared to other spaces. For example, it is conceivable to fill the space with CDA (clean dry air) to keep the space at a positive pressure, or to keep the space at a positive pressure with air passed through a dedicated circulating air conditioner using a chemical filter. .. In the dedicated circulation air conditioning, the air equivalent to the amount of air leaking when keeping the inside of the closed space at positive pressure is replenished with CDA (clean dry air), so the life of the chemical filter used for the dedicated circulation air conditioning is extended. It is possible to keep.

The space of the original stage portion 4 is maintained at a positive pressure by using air in a clean room introduced through a chemical filter mounted in a chamber containing the main body portion of the exposure apparatus. Normally, when the original plate is transported to and from the original plate storage location (not shown) connected to the original plate stage portion 4, the positive pressure of the original plate stage portion 4 is weakened, but the air in the original plate storage location is weakened. Since the cleanliness of the plate is high, it is unlikely that contaminants will invade the original stage portion 4. However, since the chemical filter mounted in the chamber always sucks the air in the clean room and supplies it into the chamber so as to keep the inside of the chamber at a positive pressure, it must be replaced appropriately according to the degree of contamination of the air in the clean room. It doesn't become. Therefore, if the chemical filter is not replaced, the ability of the chemical filter mounted on the chamber to remove contaminants is reduced, and there is a possibility that contaminants existing in the air of the clean room may invade the original stage portion 4. be.

Further, as will be described later, a contaminant enters the substrate stage 5 from a coater developer (not shown) connected to the substrate stage 5, and the contaminant passes through a gap in the exposure apparatus and enters the original stage 4. there's a possibility that.

The space of the substrate stage portion 5 is maintained at a positive pressure by using air in a clean room introduced through a chemical filter mounted in a chamber containing the main body portion of the exposure apparatus. However, a coater developer is usually connected to the substrate stage portion 5, and the substrate is conveyed between the coater developer and the optical device 100. During such transfer of the substrate, the positive pressure in the space of the substrate stage portion 5 weakens, and contaminants generated by the process material such as the photosensitive material generated by the coater developer can invade the space of the substrate stage portion 5. Further, if the chemical filter is not replaced, the ability of the chemical filter mounted on the chamber to remove contaminants is reduced, and the contaminants existing in the air of the clean room may invade the substrate stage 5. ..

Considering the cleanliness of the air in the five spaces described above, it can be said that there is little need to use an antireflection film containing a photocatalytic film for the optical elements inside the illumination optical system 2 and the projection optical system 3. Therefore, in the second embodiment, the optical element arranged at the boundary between the spaces adjacent to each other among the plurality of spaces of the optical device 100, in other words, the optical element that separates the space from the space, specifically, the seal. An antireflection film 7 including a photocatalyst film may be provided on the glass 6. From another viewpoint, the light emitted from the mercury lamp 101 (light source) is incident on the irradiated surface (photosensitive material on the substrate) through a plurality of spaces, and the optical path between the mercury lamp 101 and the irradiated surface. At least one optical element 700 including a photocatalytic film may be arranged therein. The at least one optical element 700 may include an optical element arranged at the boundary of adjacent spaces among the plurality of spaces.

In at least one of the plurality of spaces included in the optical device 100, an optical element having no photocatalytic film that affects the lower limit wavelength of light incident on the irradiated surface (photosensitive material on the substrate) is arranged. Can be done. Alternatively, in each of the plurality of spaces included in the optical device 100, an optical element not provided with a photocatalytic film that affects the lower limit wavelength of the light incident on the irradiated surface (photosensitive material on the substrate) is arranged. sell.

The light emitted from the mercury lamp 101 (light source) is incident on the irradiated surface (photosensitive material on the substrate) via the first space and the second space adjacent to each other, and the second space is the first space. Can have more pollutants. The at least one optical element includes an optical element in which an antireflection film (optical film) including a photocatalytic film is arranged so as to face the second space. Here, the photocatalyst film that affects the lower limit wavelength of the light incident on the irradiated surface may not be provided on the surface of the two surfaces of the optical element on the side of the first space.

Hereinafter, the third embodiment will be described. Matters not mentioned as the third embodiment may follow the first or second embodiment. In the third embodiment, a case where a chemically amplified resist is used as the photosensitive material is considered. In the sensitivity characteristics of the chemically amplified resist used in the manufacture of display devices such as liquid crystal display devices, it may be desirable to set the lower limit wavelength of the exposure light in the optical device 100 to 270 nm.

However, conventionally, there has not been a photocatalyst film in which the upper limit wavelength of the light absorption wavelength range matches or matches the lower limit wavelength of the exposure light wavelength range. The third embodiment provides a method of adjusting the upper limit wavelength of the light absorption wavelength range of the photocatalyst film so that the lower limit wavelength of the wavelength range of the exposure light matches the sensitivity characteristics of the chemically amplified resist. Two methods will be described below.

In the first method, an HfOx (x <2) membrane is used as the photocatalytic membrane. The photocatalyst film can be formed on the substrate (low refractive index film 703 in the configuration example of FIG. 5) by a sputtering method using Hf as a target. If the amount of oxygen gas supplied to the film forming chamber is insufficient at this time, the film formed on the substrate _{is not in the state of HfO 2} but in the state of HfOx (x <2), which causes the light absorption wavelength. The upper limit wavelength shifts to the longer wavelength side. Through experiments, the present inventor has confirmed that the upper limit wavelength of the light absorption wavelength can be adjusted to 270 nm by forming a photocatalyst film with an HfOx (x <2) film according to the above method. By adjusting the upper limit wavelength of the light absorption wavelength to 270 nm, the lower limit wavelength of the wavelength range of the exposure light is also adjusted to 270 nm.

The antireflection film (optical film) 7 or the optical member 70 manufactured by the first method may have the structure schematically shown in FIG. In one embodiment, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of an HfOx (x <2) film, which is low. The refractive index layer 701 was _{composed of a SiO 2} film. In the optical device 100 having an optical element provided with such an antireflection film (optical film) 7, the lower limit of the wavelength range of the exposure light was adjusted to 270 nm.

In the first method described above, the oxygen gas concentration when the HfOx (x <2) film is formed by the sputtering method can be adjusted. Thereby, the lower limit wavelength of the wavelength range of the exposure light can be adjusted to an arbitrary wavelength between _{240 nm when the HfO 2} film is used as the photocatalyst film and 290 nm when the Ta ₂ O _{5 film is used as the photocatalyst film.}

According to the first method, the optical member manufacturing method for manufacturing an optical member includes a treatment step of forming an optical film including a photocatalyst film on an optical element, and the treatment step includes a light absorption wavelength of the photocatalyst film. Includes a film forming step of forming the photocatalyst film so that is the target light absorption wavelength. The film forming step may include a step of forming the photocatalyst film so that the light absorption wavelength of the photocatalyst film becomes the target light absorption wavelength by adjusting the oxygen gas concentration.

In the second method, a mixed membrane of _{HfO 2} and Ta ₂ O _{5 is used as the photocatalytic membrane.} The photocatalyst film can be formed on a substrate (low refractive index film 703 in the configuration example of FIG. 5) by a vacuum vapor deposition method using a material in which _{HfO 2} and Ta ₂ O _{5 are mixed.} At this time, _{the hybrid ratio of HfO 2} and Ta ₂ O ₅ can be changed. Thereby, the lower limit wavelength of the wavelength range of the exposure light can be adjusted to an arbitrary wavelength between _{240 nm when the HfO 2} film is used as the photocatalyst film and 290 nm when the Ta ₂ O _{5 film is used as the photocatalyst film.}

The antireflection film (optical film) 7 or the optical member 70 manufactured by the second method may have the structure schematically shown in FIG. In one embodiment, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of a mixed film of _{HfO 2} and Ta ₂ O _5. The low refractive index layer 701 was _{composed of a SiO 2} film. In the optical device 100 having an optical element provided with such an antireflection film (optical film) 7, the lower limit of the wavelength range of the exposure light was adjusted to 270 nm.

Hereinafter, the fourth embodiment will be described. Matters not mentioned as the fourth embodiment may follow any of the first to third embodiments, or any combination thereof. The process gas present in the air in the clean room can cause acid to adhere to the surface of the antireflection coating. Considering this, it is desirable that the low refractive index layer (surface film covering the photocatalyst film) constituting the uppermost layer of the antireflection film is composed of a film having acid resistance.

For example, when the uppermost layer is an MgF ₂ film, MgF ₂ may change to magnesium sulfate or magnesium nitrate by the reaction with sulfuric acid or nitric acid, and the transmittance of the antireflection film may decrease. Therefore, the uppermost layer of the antireflection film may be composed of _{a SiO 2 film having resistance to sulfuric acid and nitric acid.}

However, when the uppermost layer of the antireflection film _{is composed of a SiO 2} film, when HF (hydrofluoric acid) adheres to the surface of the uppermost layer, the uppermost layer is corroded (dissolved) by HF. Here, when an organic pollutant partially adheres to the surface of the antireflection film, the portion to which the organic pollutant adheres and another portion (nothing adheres or an inorganic pollutant adheres). The dissolved amount of SiO ₂ is different between and. This difference in the amount of dissolution causes white fogging on the surface of the antireflection film and lowers the transmittance of the antireflection film.

Therefore, when HF adheres to the surface of the antireflection film in addition to sulfuric acid and / or nitric acid, the surface film of the antireflection film is an organic fluorine compound film that does not react with these acids, for example, perfluoroalkylylan ((CF). ₂ ) It is desirable to include an nSi) film.

The antireflection film (optical film) 7 or the optical member 70 according to the fourth embodiment may have a structure schematically shown in FIG.

In the first example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is _{composed of a Ta 2} O ₅ film, and is a low refractive index layer. 701 may be composed of a (CF ₂ ) nSi film.

In the second example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of an HfOx (x <2) film, and has a low refractive index. The rate layer 701 _{may be composed of a (CF 2} ) nSi film.

In the third example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of a mixed film of _{HfO 2} and Ta ₂ O _5. The low refractive index layer 701 _{may be composed of a (CF 2} ) nSi film.

In the fourth example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is _{composed of a Ta 2} O ₅ film, and is a low refractive index layer. 701 may be composed of a SiO ₂ film and a (CF ₂ ) nSi film _{covering the SiO 2 film.}

In the fifth example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of an HfOx (x <2) film, and has a low refractive index. The rate layer 701 may be composed of a SiO ₂ film and a (CF ₂ ) nSi film _{covering the SiO 2 film.}

In the sixth example, the high refractive index layer 704 is _{composed of an HfO 2} film, the low refractive index layer 703 is _{composed of a SiO 2} film, and the high refractive index layer 702 is composed of a mixed film of _{HfO 2} and Ta ₂ O _5. The low refractive index layer 701 may be composed of a SiO ₂ film and a (CF ₂ ) nSi film _{covering the SiO 2 film.}

In the fourth, fifth, and sixth examples, the SiO _{2 layer is added directly under the (CF 2} ) nSi film in the first, second, and third examples, respectively, and the lower layer and the (CF ₂ ) nSi are added. Adhesion to the film is enhanced by _{this additional SiO 2 film.}

Hereinafter, modified examples of the above-mentioned first to fourth embodiments will be described.

In the optical device 100 shown in FIG. 1, the sealing glass 62 is eliminated, an antireflection film containing a photocatalyst layer is formed on the lower surface of the lens 208 instead, and the lower surface of the lens 208 is the illumination optical system 2 and the original plate stage portion 4. It may be the boundary between the two spaces.

When the lower limit wavelength of the exposure light in the optical device 100 is set to 340 nm, which is the same as that of the conventional exposure device, an NbO ₅ film can be used _{as the photocatalyst film instead of the Ta 2} O _{5 film.} As another photocatalyst film that determines the lower limit wavelength of the wavelength range of the exposure light in the optical device 100, for example, a ZrO ₂ film or a ZnO film can be mentioned.

When the light source is composed of an Xe lamp or an Xe mercury lamp, the lower limit of the wavelength range of the light generated by the light source is 200 nm on the shorter wavelength side. Therefore, when the light source is composed of an Xe lamp or an Xe mercury lamp, and the lower limit wavelength of the wavelength range of the exposure light in the exposure apparatus is 240 nm, the photocatalytic activity is also exhibited in the _{HfO 2 film.} The antireflection film (optical film) 7 or the optical member 70 having the _{HfO 2 film as a photocatalytic film may have the structure schematically shown in FIG.} In one embodiment, the high index of refraction layer 704 is _{composed of HfO 2} film, the low index of refraction layer 703 is _{composed of SiO 2} film, the high index of refraction layer 702 is _{composed of HfO 2} film, and the low index of refraction layer 701 is composed of HfO 2 film. Was composed of a SiO ₂ film or a (CF ₂ ) nSi film. In the optical device 100 having an optical element provided with such an antireflection film (optical film) 7, the lower limit of the wavelength range of the exposure light was adjusted to 240 nm. In addition to the high refractive index layer 702, the high refractive index layer 704 can also act as a photocatalytic film.

When the light source is composed of an Xe lamp or an Xe mercury lamp and the lower limit wavelength of the exposure light in the exposure apparatus is 220 nm, the film materials are SiO ₂ and Al ₂ O ₃ , and the photocatalyst film is Al ₂ Ox (x). <3) It can be a film. When the film materials are SiO ₂ and Al ₂ O ₃ , the transmission start wavelength of the antireflection film is 200 nm.

Therefore, similarly to HfOx (x <2) described in the third embodiment, the _{Al 2} Ox (x <3) film is formed by adjusting the oxygen gas concentration when forming _{Al 2} O _{3 by the sputtering method.} can do. Thereby, the lower limit wavelength of the wavelength range of the exposure light can be set to 220 nm. The antireflection film (optical film) 7 or the optical member 70 having such a structure may have the structure schematically shown in FIG. In one embodiment, the high refractive index layer 704 is made up of an Al ₂ O ₃ film, the low refractive index layer 703 is made up of a SiO ₂ film, and the high refractive index layer 702 is made up of an Al ₂ Ox (x <3) film. The low refractive index layer 701 was composed of a SiO ₂ film or a (CF ₂ ) nSi film. In the optical device 100 having an optical element provided with such an antireflection film (optical film) 7, the lower limit of the wavelength range of the exposure light is adjusted to 220 nm.

The organic fluorine compound film constituting the uppermost layer or the surface film may be a perfluoroalkyl compound film other than the perfluoroalkylylan film. Further, the organic fluorine compound film constituting the uppermost layer or the surface film may be a perfluoroether compound film.

Next, a manufacturing method for manufacturing an article (semiconductor IC element, liquid crystal display element, MEMS, etc.) using the above-mentioned exposure apparatus will be described. The article manufacturing method includes an exposure step of exposing a photosensitive material on a substrate (wafer, a plate which is a glass substrate, etc.) using the above-mentioned exposure apparatus, and a developing step of developing the photosensitive agent, and the developing step is performed. The article is obtained from the aged substrate through other processes. Other treatments may include, for example, etching, resist stripping, dicing, bonding, packaging and the like. According to this article manufacturing method, it is possible to manufacture an article of higher quality than before.

The invention is not limited to the above embodiments, and various modifications and modifications can be made without departing from the spirit and scope of the invention. Therefore, a claim is attached to make the scope of the invention public.

101: Mercury lamp, 7: Antireflection film, 700: Optical element, 702: High bending rate film (photocatalytic film)

Claims (22)

It includes a light source that emits light having a continuous wavelength range and at least one optical element provided with an optical film including a photocatalytic film, and the light emitted from the light source is covered through the at least one optical element. An optical device that is incident on the irradiation surface.
The lower limit wavelength of the wavelength range of the light emitted from the light source and incident on the irradiated surface via the at least one optical element is determined by the light absorption characteristic of the photocatalyst film.
An optical device characterized by that. The light emitted from the light source is incident on the irradiated surface through a plurality of spaces, and the at least one optical element is an optical element arranged at a boundary between adjacent spaces among the plurality of spaces. include,
The optical device according to claim 1. In at least one of the plurality of spaces, an optical element not provided with a photocatalytic film that affects the lower limit wavelength of the light incident on the irradiated surface is arranged.
The optical device according to claim 2. In each of the plurality of spaces, an optical element not provided with a photocatalytic film that affects the lower limit wavelength of the light incident on the irradiated surface is arranged.
The optical device according to claim 2. The light emitted from the light source is incident on the irradiated surface via the first space and the second space adjacent to each other.
The second space has more contaminants than the first space and
The at least one optical element includes an optical element in which the optical film including the photocatalytic film is arranged so as to face the second space.
The optical device according to claim 1. Of the two surfaces of the optical element, the surface on the side of the first space is not provided with a photocatalyst film that affects the lower limit wavelength of the light incident on the irradiated surface.
The optical device according to claim 5. The photocatalytic membrane comprises a Ta ₂ O ₅ membrane.
The optical device according to any one of claims 1 to 6, wherein the optical device is characterized by the above. The photocatalytic membrane comprises an HfOx (x <2) membrane.
The optical device according to any one of claims 1 to 6, wherein the optical device is characterized by the above. The photocatalytic membrane comprises _{a mixed membrane of Ta 2} O ₅ and HfOx (x <2).
The optical device according to any one of claims 1 to 6, wherein the optical device is characterized by the above. The photocatalytic membrane comprises _{at least one of NbO 5} membrane, ZrO ₂ membrane, ZnO membrane and Al ₂ Ox (x <3).
The optical device according to any one of claims 1 to 6, wherein the optical device is characterized by the above. The optical film has a surface film covering the photocatalyst film, and the surface film contains a _{SiO 2 film.}
The optical device according to any one of claims 1 to 10. The optical film has a surface film covering the photocatalyst film, and the surface film contains an organic fluorine compound film.
The optical device according to any one of claims 1 to 10. The optical film has a surface film covering the photocatalytic film, and the surface film includes a perfluoroalkyl compound film or a perfluoroether compound film.
The optical device according to claim 12. The optical film is an antireflection film, and the at least one optical element is a light transmissive optical element.
The optical device according to any one of claims 1 to 13. It is configured as an exposure apparatus that exposes a substrate arranged on the irradiated surface.
The optical device according to any one of claims 1 to 14. An exposure step of exposing a photosensitive material on a substrate using the optical device according to claim 15.
It has a developing process for developing the photosensitive material, and has
The photosensitive material has photosensitivity at the lower limit wavelength and has a photosensitivity.
A method for producing an article, which comprises obtaining an article from the substrate that has undergone the development step. An exposure step of exposing a photosensitive material on a substrate using the optical device according to claim 15.
It has a developing process for developing the photosensitive material, and has
The photosensitive material has a sensitivity of 10% or more of the maximum sensitivity of the photosensitive material at the lower limit wavelength.
A method for producing an article, which comprises obtaining an article from the substrate that has undergone the development step. An optical member manufacturing method for manufacturing an optical member.
Including a processing step of forming an optical film including a photocatalytic film on an optical element,
The processing step includes a film forming step of forming the photocatalyst film so that the light absorption wavelength of the photocatalyst film becomes a target light absorption wavelength.
A method for manufacturing an optical member. The film forming step includes a step of forming the photocatalyst film so that the light absorption wavelength of the photocatalyst film becomes the target light absorption wavelength by adjusting the oxygen gas concentration.
The optical member manufacturing method according to claim 18. The photocatalytic membrane contains HfOx (x <2).
The optical member manufacturing method according to claim 18 or 19. The photocatalytic membrane contains a mixed membrane of _{HfO 2} and Ta ₂ O _5.
The optical member manufacturing method according to claim 18. The photocatalytic membrane contains Al ₂ Ox (x <3).
The optical member manufacturing method according to claim 18 or 19.

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