TW202129400A - Transmissive diffuser - Google Patents

Abstract

A diffuser is configured to receive and transmit radiation. The diffuser comprises a scattering layer configured to scatter the received radiation, the scattering layer comprising a first substance and having distributed therein a plurality of voids. The first substance may be a scattering substance, or alternatively, at least one of the voids may contain the scattering substance and the first substance has a lower refractive index than the scattering substance.

Description

Transmission diffuser

The present invention relates to a transmissive diffuser, that is, a diffuser configured to receive and transmit radiation, the transmitted radiation having a changed angular distribution. These diffusers are suitable for EUV radiation and can form part of the measurement system in the EUV lithography device.

A lithography device is a machine that is constructed to apply a desired pattern to a substrate. The lithography device can be used, for example, in the manufacture of integrated circuits (IC). The lithography device can, for example, project a pattern at a patterned device (such as a mask) onto a layer of radiation sensitive material (resist) provided on the substrate.

In order to project the pattern on the substrate, the lithography device can use electromagnetic radiation. The wavelength of this radiation determines the smallest size of features that can be formed on the substrate. Compared with a lithography device that uses radiation with a wavelength of, for example, 193 nm, a lithography device that uses extreme ultraviolet (EUV) radiation with a wavelength in the range of 4 nm to 20 nm (such as 6.7 nm or 13.5 nm) can be used To form smaller features on the substrate.

The known lithography apparatus includes a measurement system for determining changes in one or more pupil functions. The change of pupil function may include: the relative phase change in the pupil plane and/or the relative intensity change in the pupil plane. Such measurement systems usually include object level patterning devices (such as diffraction gratings or pinholes or the like); lighting systems; and image level sensor devices. The lighting system is configured to use radiation to illuminate the patterned device. At least a portion of the radiation scattered by the patterned device is received by a projection system whose properties are measured, and the projection system is configured to form an image of the patterned device on the image level sensor device. This type of measurement system requires the entire entrance pupil of the projection system to receive radiation from the patterned device. However, the lighting system is usually also used by the lithography device to form the (diffraction-limited) image of the object-level reduction mask or mask on the image-level substrate (for example, a resist-coated silicon wafer). It may be necessary to illuminate only one or more discrete parts of the entrance pupil of the projection system.

There may be a need to provide a mechanism in which the angular distribution of the illumination beam that will additionally illuminate one or more discrete parts of the entrance pupil of the projection system can be modified so that the entire entrance pupil of the projection system can receive radiation from the patterned device.

This article describes a diffuser configured to receive and transmit radiation. The diffuser includes a scattering layer configured to scatter the received radiation. The scattering layer includes a first substance and has a plurality of voids distributed therein. The first substance can be a scattering substance. Alternatively, at least one of the voids may contain a scattering material, and the first material may be a material having a lower refractive index than the scattering material. The scattering material is used to provide a micro lens array, thereby causing the radiation received by the diffuser to scatter. The diffuser can be configured to be able to change an angular distribution of the received radiation in such a way that the entire entrance pupil of the projection system can receive radiation from the patterned device.

The voids may contain a vacuum (or substantially or functionally a vacuum and an environment). Alternatively, the voids may contain a second substance, and one of the first substance and the second substance may be a scattering substance, wherein the other of the first substance and the second substance and the The scattering material has a lower refractive index than that. In the case that the first substance is the scattering substance, the second substance may be an inert gas. The substance with a lower refractive index may have a refractive index close to unity for the received radiation. Such substances can be considered to be optically neutral to the received radiation system (or relatively optically neutral compared to the scattering material). For example, if the received radiation is EUV radiation, the substance with the lower refractive index may have a refractive index close to 1 for EUV radiation. However, it should be understood that the radiation can have any wavelength (that is, it is not EUV radiation).

When the first material is the scattering material, the scattering material may include a foam having micropores and the voids can be provided by the micropores. One or more of these voids may contain vacuum or inert gas. One or more of the voids may contain one of silicon or silicon nitride. In this way, the second substance will be optically neutral to EUV radiation. In addition, the second substance will have a low attenuation to the received radiation. The material in the voids will also have a refractive index opposite to the scattering material. In addition, in this way, the scattering layer is particularly easy to manufacture, because there is no need to perform an intermediate step of removing the second substance from the scattering substance.

When the voids contain the scattering material, the first material may include a porous silicon-based structure, and the voids are defined by the micropores of the first material.

In the case of using a porous substance in an example described herein, the micropores of the porous substance may have a range of approximately several nanometers in at least one dimension.

The scattering material may include a body of contact particles. The voids can be provided between adjacent contact particles. Various deposition methods can be used, such as the liquid deposition method to make the diffuser relatively easy. Regarding the term "contacting particles", it should be understood that each particle in the particle body is in physical contact with at least one other particle in the particle body.

These particles can fuse. That is, each particle in the body of the contacting particle can be fused with at least one other particle in the body of the contacting particle. For example, sintering can be used to fuse the particles.

The particles may include a binary mixture including a first material and a second material, and a refractive index of the second material is different from the first material. The refractive indices of the first material and the second material may be opposite. The first material and the second material may have a low attenuation to the received radiation. The first material may include silicon. The second material may include molybdenum or ruthenium. It should be understood that one or both of the first material or the second material may be a mixture of two or more materials. For example, the first material may be molybdenum silicide.

The particles may have a range of approximately several nanometers in at least one dimension. The particles can be different in size in at least one dimension. That is, the particles may be polydisperse. The particle size, particle size distribution, and/or packing density of the particles can be selected based on one or more desired properties of the scattering layer, such as high scattering angle and/or suppression of zero-order scattering.

The scattering substance may include a substance with a ratio of a first parameter to a second parameter of or less than 1, wherein the first parameter is the maximum thickness of a layer of the substance that will allow 10% of the received radiation to be transmitted, And the second parameter is the minimum thickness of a layer of the substance that will cause a phase shift of Pi nm.

For example only, for example, the scattering material may be molybdenum, ruthenium, niobium, rhodium, yttrium, boron, molybdenum disilicide, zirconium, rhodium, or tectonium.

The voids may be distributed in a plurality of layers within the first substance, each layer being substantially in a plane perpendicular to the propagation direction of the radiation during use.

The voids may be distributed in a single layer within the first substance, the layer being substantially in a plane perpendicular to the propagation direction of the radiation during use.

The scattering material may include a dealloying material. The dealloying material will provide a scattering material with multiple interfaces with the voids.

The voids may have a range of approximately several nanometers in at least one dimension. The voids may be polydisperse within the first material. The voids can be randomly or randomly arranged in the first material.

The scattering layer may have a thickness between 50 nm and 1000 nm. The thickness of the material is measured in a propagation direction of the received radiation during the use of the diffuser.

The diffuser can be configured so that the angular scattering distribution in at least one scattering direction has a width of 5° or more. The scattering direction may preferably have a width of 9° or more.

The scattering material may include one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, or typhthium.

The diffuser may include a plurality of scattering layers. Each of the scattering layers can be manufactured according to any technique described herein or elsewhere.

A first scattering layer can be separated from a second scattering layer by an intermediate layer. The intermediate layer may comprise silicon, or some other material that is relatively optically neutral to the received radiation.

The intermediate layer may include a layer of separated particles having a lower refractive index than the scattering material. Because the particles are separated, at least a part of the intermediate layer can be occupied by, for example, inert gas or vacuum, thereby reducing the attenuation of the received radiation.

The separated particles can be randomly or randomly arranged in the intermediate layer. The separated particles may include particles of different sizes in at least one dimension.

The first substance and the voids therein can cooperate to generate a holographic image after receiving radiation at a surface of the scattering layer. That is, the first substance and the voids may include a holographic interference pattern. The holographic interference pattern can be selected to form a desired holographic image given a desired wavelength of radiation. The radiation may be EUV radiation. The first substance can be a scattering substance. Diffusers operable to produce holographic images can be beneficially combined with minimal absorption of radiation to provide controlled diffusion of radiation. This diffuser can have an increased lifetime compared to known diffusers, for example due to reduced absorption of radiation.

The hologram may have an angular intensity profile that is at least as strong in a radially outer portion of the hologram compared to a central region of the hologram. The angular intensity profile may have a similar intensity in a central area compared to a radially outer part of the holographic image. The angular strength profile can be a top hat-shaped profile. The angular intensity profile may have a lower intensity in a central region than a radially outer part of the holographic image.

The radially outer part may be angularly separated from the center of the holographic image by at least 9°. This diffuser can have specific benefits in devices with high numerical apertures.

The first substance may include a plurality of structures with varying thickness. That is, the thickness profile of the plurality of structures changes. The thickness profile can be measured in a plane of the diffuser, such as the plane of a surface configured to receive radiation. The thickness profile can vary by a few nanometers. For example, the thickness profile of the structures can vary between a thickness of 0 nm and 200 nm.

之輻射後形成該全像圖。該波長可為一EUV波長。該全像漫散器可具有一有效折射率

。該複數個結構中之每一者之厚度可為

的整數倍。有益地，此漫散器可向行進通過其之輻射之部分賦予為0、pi或2 pi之相移。The diffuser is operable to have a wavelength

The holographic image is formed after the radiation. The wavelength may be an EUV wavelength. The holographic diffuser may have an effective refractive index

. The thickness of each of the plurality of structures can be

Integer multiples of. Advantageously, this diffuser can impart a phase shift of 0, pi, or 2 pi to the portion of the radiation traveling through it.

The voids may contain a second substance. That is, a second substance can be provided to fill the voids.

The real part of the refractive index of the second substance may be different from the real part of the refractive index of the first substance. Advantageously, the first and second substances having different real parts of their refractive indices can scatter radiation. The imaginary part of the second substance may be similar to the imaginary part of the refractive index of the first substance. Advantageously, the first and second substances having similar imaginary parts of their refractive indices can reduce the attenuation through the diffuser. The combined first and second substances are used to reduce the relative difference in attenuation experienced by radiation traveling through the structure and voids.

The combined first substance and second substance may have a substantially constant combined thickness profile. That is, the surface of the diffuser configured to receive radiation is substantially smooth. The surface can be smooth on the microscale. The surface can be smooth on the nanometer scale.

The first substance may include one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, or tectonium. The second substance may include silicon.

A holographic diffuser is also described herein, which includes a scattering layer, the scattering layer includes a plurality of structures, and the plurality of structures are configured to generate a holographic diffuser after receiving extreme ultraviolet radiation at a surface of the scattering layer. An image diagram, wherein the holographic image has an angular intensity profile that is at least as strong in a radially outer portion of the holographic image as compared to a central region of the holographic image.

Any diffuser described herein may further include a protective layer configured to protect the scattering layer from EUV plasma etching. The diffuser may further include a cap layer that at least partially covers the scattering layer to protect the scattering layer during use.

A measurement system for determining an aberration map or a relative intensity map for a projection system is also described herein. The measurement system includes a diffuser of any of the examples described herein.

The measurement system may include: a patterned device; an illumination system configured to illuminate the patterned device with radiation; and a sensor device. The illumination system and the patterned device are configured such that the projection system receives at least a portion of the radiation scattered by the patterned device and the sensor device is configured such that the projection system projects the received radiation to The sensor device is on. The diffuser is operable to receive the radiation generated by the illumination system and change an angular distribution of the radiation before the radiation illuminates the patterned device.

The diffuser is movable between at least the following positions: a first operating position, wherein the diffuser is at least partially disposed in a path of the radiation generated by the lighting system and is configured to illuminate the radiation The patterned device previously changes an angular distribution of the radiation; and a second storage position, wherein the diffuser is arranged outside the path of the radiation generated by the illumination system.

When the measurement system as described herein is used with the holographic diffuser as described herein, the holographic diffuser can be designed and/or configured such that the holographic image is formed at the input of the measurement system Plane. The input plane may include the input plane of the sensor device of the measurement system.

A lithography apparatus is also described herein, which includes: a measurement system as described in any of the examples herein; and a projection system configured to receive at least a portion of the radiation scattered by the patterned device And is configured to project the received radiation onto the sensor device.

The diffuser can be installed on a patterned device shielding blade of the lithography device, and an edge of the patterned device shielding blades defines a field area of the lithography device.

A method of forming a diffuser for receiving and transmitting radiation is also described herein. The method includes forming an alloy layer, the layer including a first substance and a third substance, wherein the first substance is a scattering substance. The method further includes dealloying the alloy layer to remove the third substance from the alloy layer and to form a scattering layer containing the first substance and having a plurality of voids distributed therein.

The second substance may be zinc, and the dealloying may be dezincification.

A method of forming a diffuser for receiving and transmitting radiation is also described herein. The method includes forming a scattering layer by penetrating a porous structure with a scattering material.

The porous structure may be porous silicon. The micropores may have a range of approximately several nanometers in at least one dimension.

The scattering layer can be formed on a supporting layer.

A method of forming a diffuser for receiving and transmitting radiation is also described. The method includes: depositing a plurality of particles on a surface of a support layer to form a mask; and on the support layer above the mask A scattering material is deposited to surround the plurality of particles to form a scattering layer.

The second material may be a material that is relatively optically neutral to the intended radiation. For example, the second material may be relatively optically neutral to EUV radiation. For example, the second material can be silicon.

The method may further include shrinking one or more of the plurality of particles deposited on the support layer so as to expose a larger area of the surface of the support layer before depositing the scattering material.

The particles can be deposited on the support layer via vertical colloid deposition. The particles can form a single layer deposited on the surface of the support layer, and the scattering layer forms a wave scattering surface on the support layer. The particles form a plurality of layers deposited on the surface of the support layer, each of the plurality of layers in use in a plane that is substantially perpendicular to a direction of the received radiation.

The method may further include removing the particles after depositing the scattering material.

A method of forming a diffuser for receiving and transmitting radiation is also described. The method includes: depositing a plurality of particles on a surface of a supporting layer to form a mask; A second material is deposited on the surface to form a layer of the second material around the plurality of particles; at least some of the plurality of particles are removed to form pits in the layer of the second material; and a scattering material Deposited into at least some of the pits in the second material to form scattering features in the layer of the second material.

A method of forming a diffuser for receiving and transmitting radiation is also described. The method includes: depositing a plurality of particles on a surface of a supporting layer to form a mask; A second material is deposited on the surface; the surface of the support layer is selectively etched to form a plurality of structures on the surface of the support layer; a scattering material is deposited on the surface of the support layer, the scattering material Formed over the plurality of structures to form a scattering layer; wherein the second material is a catalyst and the selective etching includes etching the area of the support layer in contact with the second material, or wherein the second material is a protection And the selective etching includes etching areas of the support layer that are not in contact with the second material.

A method of forming a diffuser for receiving and transmitting radiation is also described herein. The method includes depositing a plurality of particles on a surface of a support layer so that the particles form a body that contacts the particles. The particles can be deposited from the dispersion of the particles in the liquid. The particles can be deposited at a particle density such that most of the particles are in contact with one or more neighboring particles.

The deposition may include at least one of the following: vertical colloidal deposition, spin coating, and inkjet printing. This type of deposition method provides an easy diffuser manufacturing method.

Depositing the plurality of particles may further include fusing the plurality of particles. The plurality of particles can be fused by providing heat and/or pressure. The plurality of particles can be fused using sintering.

The particles may include a binary mixture including a first material and a second material, and a refractive index of the second material is different from the first material. The first material may include molybdenum, ruthenium, niobium, rhodium, yttrium, or tectonium. The second material may include silicon.

The method may further include forming another scattering layer on the diffuser. The other scattering layer can be formed according to the method of any of the examples described herein.

Forming another scattering layer may include depositing an intermediate layer over the scattering layer and forming the other scattering layer on top of the intermediate layer. For example, the intermediate layer can be silicon or silicon nitride.

In any of the example methods described herein for forming a diffuser, the support layer may be formed on a carrier layer that is used to support the support layer when forming the diffuser And wherein the method further includes removing the carrier layer once the first layer and the second layer have been formed. The carrier layer can be, for example, silicon. For example, the carrier layer can be a standard silicon wafer of the type commonly used in semiconductor manufacturing.

Also described herein is a method of forming a diffuser for receiving and transmitting radiation. The method includes generating a plurality of structures on a surface of a supporting layer of the diffuser, wherein the structures are configured to lie in the diffuser. After receiving the radiation at the surface, a holographic image is produced. The radiation may be EUV radiation. Diffusers operable to produce holographic images can be beneficially combined with minimal absorption of radiation to provide controlled diffusion of radiation. This diffuser can have an increased lifetime compared to known diffusers, for example due to reduced absorption of radiation.

The hologram may have an angular intensity profile that is at least as strong in a radially outer portion of the hologram compared to a central region of the hologram. The angular intensity profile may have a similar intensity in a central area compared to a radially outer part of the holographic image. The angular strength profile can be a top hat-shaped profile. The angular intensity profile may have a lower intensity in a central region than a radially outer part of the holographic image. The radially outer part may be angularly separated from the center of the holographic image by at least 9°. This diffuser can have specific benefits in devices with high numerical apertures.

之整數倍的厚度，其中

為當由漫散器接收時產生全像圖的輻射之波長，且全像漫散器具有有效折射率

。Lithography can be used to create the plurality of structures. Each part of the plural structures can be

An integer multiple of the thickness, where

Is the wavelength of the radiation that produces the holographic image when received by the diffuser, and the holographic diffuser has an effective refractive index

.

The method may further include depositing a second substance into a plurality of voids distributed in the plurality of structures. The second substance has a thickness such that a combined thickness profile of the first substance and the second substance is substantially constant. That is, after the second substance is provided, the surface of the diffuser that is operable to generate a holographic image after receiving a radiation may be substantially smooth. The second substance can be a scattering substance. The real part of the refractive index of the second substance may be different from the real part of the refractive index of the first substance. Advantageously, the first and second substances having different real parts of their refractive indices can scatter radiation. The imaginary part of the second substance may be similar to the imaginary part of the refractive index of the first substance. Advantageously, the first and second substances having similar imaginary parts of their refractive indices can reduce the attenuation through the diffuser. The combined first and second substances are used to reduce the relative difference in attenuation experienced by radiation traveling through the structure and voids.

The method may further include generating a thickness profile corresponding to a desired configuration of one of the plurality of surface features, the desired configuration being based on a desired angle profile of the holographic image. Generating the thickness profile can include numerical methods. Generating the thickness profile may include iteratively solving and/or performing calculations based on optical relationships. These optical relationships can represent one or more of the following: attenuation, refractive index, scattering angle, layer thickness, phase shift. The thickness profile generation may include restrictions on the maximum and/or minimum allowable thickness. The maximum and/or minimum allowable thicknesses can be based on manufacturing parameters. The maximum and/or minimum allowable thicknesses can be based on desired optical properties, such as attenuation.

Generating the thickness profile may include using a Gerchberg-Saxton algorithm. Generating the thickness profile may include using a modified version of the Geschberg-Sachsston algorithm.

Any of the example methods of forming a diffuser described herein can further include etching the support layer from a surface of the support layer opposite to a surface of the support layer that supports the scattering layer.

Any of the example methods described herein for forming a diffuser can further include providing a cap layer at least partially covering the support layer and/or the scattering layer.

The methods described herein may further comprise once the plurality of nanoparticles have been deposited to form the nanoparticle layer supported by the support layer, from the support layer and the support layer supporting the nanoparticle The supporting layer is etched on the opposite surface of one of the layers.

This backside etching of the support layer allows a thicker, more stable support layer to be used during the manufacture of the diffuser. Advantageously, this prevents damage or even breakage of the support layer. For embodiments in which a colloid is used to deposit nanoparticles, this final etching step can be particularly beneficial because it prevents capillary forces from braking the support layer. Once the nanoparticle layer has been formed, an etching process can be used to determine the thickness of the layer.

The methods described herein may further include providing a cover layer that at least partially covers the support layer and/or the cover layer.

The term patterned device as used herein may also be referred to as a mask or a reduction mask, and these terms will be understood as synonymous.

Fig. 1 shows a lithography system including a radiation source SO and a lithography device LA. The radiation source SO is configured to generate the EUV radiation beam B and supply the EUV radiation beam B to the lithography device LA. The lithography apparatus LA includes an illumination system IL, a support structure MT configured to support a patterned device MA (such as a mask), a projection system PS, and a substrate table WT configured to support a substrate W.

The illumination system IL is configured to adjust the EUV radiation beam B before it is incident on the patterned device MA. The illumination system IL may include a faceted field mirror device 10 and a faceted pupil mirror device 11. The faceted field mirror device 10 and the faceted pupil mirror device 11 together provide the EUV radiation beam B with a desired cross-sectional shape and a desired angular distribution. In addition to the faceted field mirror device 10 and the faceted pupil mirror device 11 or instead of the faceted field mirror device 10 and the faceted pupil mirror device 11, the illumination system IL may also include other mirror surfaces or devices.

After being adjusted accordingly, the EUV radiation beam B interacts with the patterned device MA. As a result of this interaction, a patterned EUV radiation beam B'is generated. The projection system PS is configured to project the patterned EUV radiation beam B′ onto the substrate W. For that purpose, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B′ onto the substrate W held by the substrate table WT. The projection system PS can apply the reduction factor to the patterned EUV radiation beam B', thereby forming an image with features smaller than the corresponding features on the patterned device MA. For example, a reduction factor of 4 or 8 can be applied. Although the projection system PS is illustrated in FIG. 1 as having only two mirror surfaces 13, 14, the projection system PS may include a different number of mirror surfaces (for example, six or eight mirror surfaces).

The substrate W may include a previously formed pattern. In this situation, the lithography device LA aligns the image formed by the patterned EUV radiation beam B′ with the pattern previously formed on the substrate W.

A relatively vacuum, that is, a small amount of gas (such as hydrogen) at a pressure sufficiently lower than atmospheric pressure may be provided in the radiation source SO, in the illumination system IL, and/or in the projection system PS.

The radiation source SO can be a laser generating plasma (LPP) source, a discharge generating plasma (DPP) source, a free electron laser (FEL) or any other radiation source capable of generating EUV radiation.

The lithography device can be used, for example, in a scanning mode, in which when projecting the pattern imparted to the radiation beam onto the substrate W, the support structure (for example, the mask stage) MT and the substrate stage WT (that is, the dynamic exposure). The speed and direction of the substrate table WT relative to the support structure (for example, the mask table) MT can be determined by the reduction ratio and image inversion characteristics of the projection system PS. The patterned radiation beam incident on the substrate W may include a radiation band. The radiation zone can be referred to as an exposure slit. During the scanning exposure, the movement of the substrate table WT and the support structure MT can cause the exposure slit to travel across the exposure field of the substrate W.

As described above, the lithography device can be used to expose a portion of the substrate W to form a pattern in the substrate W. In order to improve the accuracy of transferring the desired pattern to the substrate W, one or more attributes of the photolithography device LA can be measured. Such attributes may be measured on a conventional basis, for example, before and/or after exposure of each substrate W, or may be less frequent, for example, measured as part of a calibration procedure. Examples of measurable properties of the lithography device LA include the relative alignment of the components of the lithography device LA and/or the aberration of the components of the lithography device. For example, measurement can be performed to determine the relative alignment of the support structure MT for supporting the patterned device MA and the substrate table WT for supporting the substrate W. It is determined that the relative alignment of the support structure MT and the substrate table WT will assist in projecting the patterned radiation beam onto the desired portion of the substrate W. This can be particularly important when projecting patterned radiation onto a substrate W that includes portions that have been exposed to radiation, in order to improve the alignment of the patterned radiation with previously exposed areas. Additionally or alternatively, measurements can be performed to determine the deformation of the patterned device MA.

Additionally or alternatively, measurements can be made to determine the optical aberration of the projection system PS. Optical aberration is the deviation of the efficiency of the optical system from the paraxial optical device and can cause blur or distortion of the pattern exposed at the substrate W. The aberration of the projection system PS can be adjusted and/or considered to increase the accuracy of the desired pattern formed on the substrate W.

Measurements, such as the alignment and aberration measurements described above, can be performed by using radiation to illuminate the reflective marker 17 (shown schematically in FIG. 1). In an alternative configuration, transmissive markers can be used. The marker is a reflective feature, which appears in the image generated by the optical system when it is placed in the field of view of the optical system. The reflective markers described herein are suitable for use as a reference point and/or as a measure of the properties of the image formed by the optical system. For example, the radiation reflected from the reflective marker can be used to determine the alignment of one or more components and/or the optical aberration of one or more components.

In the embodiment shown in FIG. 1, the reflective marker 17 forms part of the patterned device MA. One or more markers 17 may be provided on the patterned device MA used to perform lithographic exposure. The marker 17 may be positioned outside the patterned area of the patterned device MA, and the patterned area is illuminated with radiation during the photolithographic exposure. In some embodiments, one or more markers 17 may additionally or alternatively be provided on the support structure MT. For example, dedicated hardware components (often referred to as reference components) can be provided on the support structure MT. The fiducial can include one or more markers. For the purposes of this specification, the fiducial is considered an example of a patterned device. In some embodiments, a patterned device MA specifically designed to measure one or more properties of the lithography apparatus LA may be placed on the support structure MT to perform the measurement procedure. The patterned device MA may include one or more markers 17 for illumination as part of the measurement procedure.

In the embodiment shown in FIG. 1, the lithography device LA is an EUV lithography device and therefore uses a reflective patterning device MA. The marker 17 is therefore a reflective marker 17. The configuration of the marker 17 may depend on the nature of the measurement to be performed using the marker 17. The marker may, for example, include one or more reflective pinhole features, the one or more reflective pinhole features including a reflective area surrounded by an absorption region, a reflective line feature, a plurality of reflective line features, and/or such as a reflective diffraction grating. Configuration of reflective grating structure.

In order to measure one or more properties of the lithography device LA, a sensor device 19 (as shown schematically in FIG. 1) is provided to measure the radiation output from the projection system PS. As shown in FIG. 1, the sensor device 19 may be provided on the substrate table WT, for example. In order to perform the measurement procedure, the support structure MT can be positioned so that the marker 17 on the patterned device MA is illuminated with radiation. The substrate table WT may be positioned such that the radiation reflected from the marker is projected onto the sensor device 19 by the projection system PS. The sensor device 19 communicates with the controller CN, and the controller can determine one or more attributes of the lithography device LA based on the measurement performed by the sensor device 19. In some embodiments, a plurality of markers 17 and/or sensor devices 19 can be provided, and the photomicrography can be measured at a plurality of different field points (ie, the field of the projection system PS or the position in the object plane) The attributes of the device LA.

As described above, in some embodiments, the radiation reflected from the marker can be used to determine the relative alignment of the components of the lithography apparatus LA. In such embodiments, the marker 17 may include a feature that imparts alignment characteristics to the radiation when radiant illumination is used. For example, the feature may include one or more reflective patterns in the form of a grating structure.

The position of the alignment feature in the radiation beam B can be measured by the sensor device 19 positioned at the level of the substrate W (for example, on the substrate table WT as shown in FIG. 1). The sensor device 19 is operable to detect the position of the alignment feature in the radiation incident thereon. This may allow determining the alignment of the substrate table WT with respect to the marker on the patterned device MA. Knowing the relative alignment of the patterned device MA and the substrate table WT, the patterned device MA and the substrate table WT can move relative to each other to form a pattern at a desired position on the substrate W (using a reflection from the patterned device MA Patterned radiation beam B). A separate measurement program can be used to determine the position of the substrate W on the substrate stage.

As further described above, in some embodiments, the patterned device MA may be provided with one or more markers 17 that can be used to measure the aberration of the projection system PS. Similar to the alignment measurement described above, the aberration can be detected by measuring the radiation reflected from the marker 17 using the sensor device 19 located at or near the substrate table WT. The illumination system IL can use EUV radiation to illuminate one or more markers 17 on the patterned device MA. The radiation reflected from one or more markers is projected by the projection system PS onto the image plane of the projection system PS. One or more sensor devices 19 are positioned at or near the image plane (for example, on the substrate table WT as shown in FIG. 1), and can measure the projected radiation to determine the aberration of the projection system PS. Now, embodiments of the marker 17 and the sensor device 19 that can be used to determine the aberration of the projection system PS will be described with reference to FIGS. 2 and 3.

Figure 2 is a schematic representation of a marker 17 that can form part of a patterned device MA according to an embodiment of the present invention. Figure 2 also shows the Cartesian coordinate system. The y direction can indicate the scanning direction of the lithography device. That is, during the scanning exposure, the movement of the substrate table WT and the support structure MT can cause the patterned device MA to be scanned relative to the substrate W in the y direction. The marker 17 is generally located in the x-y plane. That is, the marker extends substantially in a direction perpendicular to the z direction. Although referring to a marker that is generally located in a plane, it should be understood that the marker is not completely constrained to a plane. That is, the portion of the marker can extend beyond the plane in which the marker is substantially located. As will be explained further below, the marker may include a diffraction grating. The diffraction grating may include a three-dimensional structure, which includes a portion that does not lie entirely in the plane but instead extends out of the plane.

The marker 17 shown in FIG. 2 includes a first portion 17a and a second portion 17b. Both the first and second parts include a reflection diffraction grating that includes a periodic grating structure. The grating structure extends in the grating direction. The first part 17a includes a diffraction grating extending in a first grating direction, which is denoted as the u direction in FIG. 2. The second portion 17b includes a diffraction grating extending in a second grating direction, which is denoted as the v direction in FIG. 2. In the embodiment of FIG. 2, both the u direction and the v direction are aligned at approximately 45° with respect to both the x and y directions and are generally perpendicular to each other. The first part 17a and the second part 17b of the marker 17 can be illuminated with radiation at the same or different times.

Although the embodiment shown in FIG. 2 includes a first portion 17a and a second portion 17b including a diffraction grating oriented in a vertical grating direction, in other embodiments, the marker 17 may be provided in other forms. For example, the marker 17 may include reflection and absorption regions configured to form a checkerboard pattern. In some embodiments, the marker 17 may include an array of pinhole features. The reflective pinhole feature may include a region of reflective material surrounded by absorbing material.

When the first part 17a and/or the second part 17b of the marker is illuminated with radiation, a plurality of diffraction orders are reflected from the marker. At least a part of the reflection diffraction order enters the projection system PS. The projection system PS forms an image of the marker 17 on the sensor device 19. 3A and 3B are schematic illustrations of the sensor device 19. Fig. 3A is a side view of the sensor device and Fig. 3B is a top view of the sensor device. The Cartesian coordinates are also shown in FIGS. 3A and 3B.

The Cartesian coordinate system used in Figures 2, 3A and 3B is intended to be the coordinate system of radiation propagating through the lithography device. At each reflective optical element, the z direction is defined as the direction perpendicular to the optical element. That is, in FIG. 2, the z direction is perpendicular to the x-y plane where the patterned device MA and the marker 17 generally extend. In FIGS. 3A and 3B, the z direction is perpendicular to the x-y plane where the diffraction grating 19 and the radiation sensor 23 generally extend. The y direction represents the scanning direction, wherein during scanning exposure, the support structure MT and/or the substrate table WT are scanned relative to each other. The x direction represents the non-scanning direction perpendicular to the scanning direction. It should be understood (for example, from FIG. 1) that in the lithography apparatus, the z-direction at the patterned device MA is not aligned with the z-direction at the substrate W. As explained above, the z-direction is defined as perpendicular to the optical element at each optical element in the lithography device.

The sensor device 19 includes a transmission diffraction grating 21 and a radiation sensor 23. At least some of the radiation 25 output from the projection system PS passes through the diffraction grating 21 and is incident on the radiation sensor 23. The diffraction grating 21 is shown in more detail in FIG. 3B and includes a checkerboard-shaped diffraction grating. The shaded black area of the diffraction grating 21 shown in FIG. 3B represents the area of the diffraction grating 21 that is configured to be substantially opaque to incident radiation. The non-shaded area of the diffraction grating 21 shown in FIG. 3B represents the area configured to transmit radiation. For ease of description, the opaque and transmissive regions of the diffraction grating 21 are not shown to scale in FIG. 3B. For example, in practice, relative to the size of the diffraction grating itself, the ratio of the features of the diffraction grating can be smaller than that indicated in FIG. 3B.

The diffraction grating 21 shown in FIG. 3B is depicted as having a checkerboard configuration including square transmission and opaque areas. However, in practice, it may be difficult or impossible to manufacture a transmission diffraction grating that includes perfect square transmission and opaque regions. The transmissive and/or opaque zone may therefore have a cross-sectional shape other than a perfect square. For example, the transmissive and/or opaque region may have a cross-sectional shape including a square (or more generally rectangular) with rounded corners. In some embodiments, the transmissive and/or opaque regions may have a substantially circular or elliptical cross-sectional shape. In some embodiments, the diffraction grating 21 may include a pinhole array formed of an opaque material.

The radiation sensor 23 is configured to detect the spatial intensity profile of the radiation incident on the radiation detector 23. The radiation detector 23 may, for example, include an array of individual detector elements. For example, the radiation detector 23 may include a CCD or CMOS array. During the procedure for determining aberrations, the support structure MT can be positioned so that the marker 17 is illuminated with radiation from the illumination system IL. The substrate table WT can be positioned so that the radiation reflected from the marker is projected onto the sensor device 19 by the projection system PS.

As described above, a plurality of diffraction steps are formed at the marker 17. Other radiation diffraction occurs at the diffraction grating 21. The interaction between the diffraction step formed at the marker 17 and the diffraction pattern formed at the diffraction grating 21 will result in the formation of an interference pattern on the radiation detector 23. The interference pattern is the derivative of the phase of the wavefront that has propagated through the projection system. The interference pattern can therefore be used to determine the aberration of the projection system PS.

As described above, the first and second portions of the marker 17 include diffraction gratings aligned vertically with each other. The radiation reflected from the first portion 17a of the marker 17 can provide information about the gradient of the wavefront along the first direction. The radiation reflected from the second portion 17b of the marker can provide information about the gradient of the wavefront along a second direction, which is perpendicular to the first direction. In some embodiments, the first and second portions of the marker can be illuminated at different times. For example, the first part 17a of the marker 17 can be illuminated at a first time to derive information about the wavefront gradient along the first direction, and the second part 17b of the marker 17 can be illuminated at a second time so as to Derive information about the wavefront gradient along the second direction.

In some embodiments, the patterned device MA and/or the sensor device 19 may be sequentially scanned and/or stepped in two vertical directions. For example, the patterned device MA and/or the sensor device 19 can be stepped relative to each other in the u and v directions. When the second part 17b of the marker 17 is illuminated, the patterning device MA and/or the sensor device 19 can be stepped in the u direction, and when the first part 17a of the marker 17 is illuminated, the patterning The device MA and/or the sensor device 19 can be stepped in the v direction. That is, the patterned device MA and/or the sensor device 19 can be stepped in a direction perpendicular to the grating direction of the illuminated diffraction grating.

The patterned device MA and/or the sensor device 19 can be stepped to a distance corresponding to a fraction of the grating period of the diffraction grating. The measurements performed at different step positions can be analyzed to derive information about the wavefront in the step direction. For example, the phase of the first harmonic of the measured signal may contain information about the derivative of the wavefront in the step direction. Therefore, stepping the patterned device MA and/or the sensor device 19 in both the u-direction and the v-direction (which are perpendicular to each other) will allow information about the wavefront in the two perpendicular directions to be derived, thereby Allow reconstruction of the full wavefront.

In addition to making the patterned device MA and/or the sensor device 19 step in a direction perpendicular to the grating direction of the diffraction grating being illuminated (as described above), the patterned device MA and/or the sensor The devices 19 can also scan relative to each other. The scanning of the patterned device MA and/or the sensor device 19 can be performed in a direction parallel to the grating direction of the diffraction grating being illuminated. For example, when the first part 17a of the marker 17 is illuminated, the patterned device MA and/or the sensor device 19 can be scanned in the u direction, and when the second part 17a of the marker 17 is illuminated At the same time, the patterned device MA and/or the sensor device 19 can be scanned in the v direction. The scanning of the patterned device MA and/or the sensor device 19 in a direction parallel to the raster direction of the diffraction grating being illuminated allows the measurement across the diffraction grating to be averaged, thereby considering the scanning direction Any changes in the diffraction grating above. The scanning of the patterned device MA and/or the sensor device 19 may be performed at a time different from the step of the patterned device MA and/or the sensor device 19 described above.

As described above, the diffraction grating 21 forming part of the sensor device 19 is configured in the form of a checkerboard. This may allow the sensor device 19 to be used during the determination of wavefront phase changes in both the u-direction and the v-direction. The configuration of the diffraction grating forming the marker 17 and the sensor device 19 is presented only as an example embodiment. It should be understood that many different configurations can be used in order to determine wavefront changes.

In some embodiments, the marker 19 and/or the sensor device 19 may include components other than diffraction gratings. For example, in some embodiments, the marker 17 and/or the sensor device 19 may include a single slit or one or more pinhole features, and at least a portion of the radiation beam may propagate through the single slit or one or more Pinhole feature. In the case of the marker 17, the pinhole feature may comprise a part of the reflective material surrounded by the absorbing material so that the radiation is only reflected from a smaller part of the marker. The single slit feature may have the form of a single strip of reflective material surrounded by absorbing material. The pinhole feature and/or the single slit feature at the sensor device 19 may be a transmission feature. Generally speaking, the marker 17 can be any feature that imparts a feature to the radiation beam, and the feature can be used as a reference point or used to determine the measurement of the radiation beam.

Although in the above-described embodiment, a single marker 17 and sensor device 19 are provided, in other embodiments, a plurality of markers 17 and sensor devices 19 may be provided to measure different field points. The wavefront phase changes. Generally speaking, any number and configuration of markers and sensor devices 19 can be used to provide information about the phase change of the wavefront.

The controller CN (as shown in FIG. 1) receives the measurements made at the sensor device 19, and determines the aberration of the projection system PS from the measurements. The controller can be further configured to control one or more components of the lithography apparatus LA. For example, the controller CN may control a positioning device that is operable to move the substrate table WT and/or the support structure MT relative to each other. The controller CN can control the adjustment member PA for adjusting the components of the projection system PS. For example, the adjustment member PA can adjust the elements of the projection system PS so as to correct the aberration determined by the controller CN.

The projection system PS includes a plurality of reflective lens elements 13, 14 and an adjustment member PA for adjusting the lens elements 13, 14 to correct aberrations. In order to achieve this correction, the adjustment member PA is operable to manipulate the reflective lens elements in the projection system PS in one or more different ways. The adjustment member PA is operable to perform any combination of: displacing one or more lens elements; tilting one or more lens elements; and/or deforming one or more lens elements.

The projection system PS has a non-uniform optical transfer function, which can affect the pattern imaged on the substrate W. For unpolarized radiation, this type of effect can be described quite well by two scalar maps that describe the transmission of radiation that varies depending on the position in the pupil plane of the radiation exiting the projection system PS ( Apodization) and relative phase (aberration). These scalar maps, which can be called transmission maps and relative phase maps, can be expressed as linear combinations of the complete set of basis functions. It should be understood that the terms "transmission map" and "relative intensity map" are synonymous and the transmission map may alternatively be referred to as a relative intensity map. A particularly suitable set of basis functions for expressing these scalar maps is Zernike polynomials, which form a set of orthogonal polynomials defined on the unit circle. The determination of each scalar map may involve determining the coefficients in this expansion. Since Rennick polynomials are orthogonal on the unit circle, it can be determined by sequentially calculating the inner product of the measured scalar map and each Rennick polynomial and dividing the inner product by the square of the norm of the Rennick polynomial Rennick coefficient.

The transmission map and relative phase map are field and system dependent. That is, generally speaking, each projection system PS will have a different Rennick expansion for each field point (that is, for each spatial position in the image plane of the projection system PS).

Determining the aberration of the projection system PS may include fitting the wavefront measurement performed by the sensor device 19 to the Rennick polynomial so as to obtain the Rennick coefficient. Different Renike coefficients can provide information about different forms of aberrations caused by the projection system PS. The Rennick coefficient can be determined independently at different positions (that is, at different field points) in the x and/or y direction.

Different Renike coefficients can provide information about different forms of aberrations caused by the projection system PS. Generally, Rennick polynomials are considered to contain a plurality of orders, and each order has an associated Rennick coefficient. The index can be used to mark the order and coefficients, and the index is usually called the Noll index. The Rennick coefficient with a Knoll index of 1 may be called the first Knick coefficient, the Rennick coefficient with a Knoll index of 2 may be called the second Nick coefficient, and so on.

The first Nick coefficient refers to the average value of the measured wavefront (which can be called Piston). The first nick coefficient may not be related to the performance of the projection system PS, and therefore, the method described herein may not be used to determine the first nick coefficient. The second Nick coefficient is related to the inclination of the measured wavefront in the x direction. The tilt of the wavefront in the x direction is equivalent to the placement in the x direction. The third term Nick coefficient relates to the tilt of the measured wavefront in the y direction. The tilt of the wavefront in the y direction is equivalent to the placement in the y direction. The fourth Nick coefficient relates to the defocus of the measured wavefront. The fourth Nick coefficient is equivalent to the placement in the z direction. The high-order Rennick coefficients are related to other forms of aberration (such as astigmatism, coma, spherical aberration, and other effects).

Throughout this specification, the term "aberration" is intended to include all forms of deviation of the wavefront from the perfect spherical wavefront. That is, the term "aberration" may be related to the placement of images (for example, the second, third, and fourth Nick coefficients) and/or to higher-order aberrations, such as those with a Knoll index of 5 or greater The aberration of Rennick coefficient.

As described in detail above, one or more reflective markers 17 can be used to determine the alignment and or aberrations of the components of the lithography apparatus LA. In some embodiments, the separate marker 17 can be used to determine the alignment of the component and the marker used to determine aberrations. For example, the patterned device MA suitable for the lithographic exposure process may be provided with one or more markers outside the patterned area suitable for the lithographic exposure process. The one or more markers may be suitable for determining the alignment of the patterned device MA relative to the substrate table WT.

One or more markers 17 suitable for determining aberrations may be provided on the measurement patterning device, which is separated from the patterning device MA (for example, a reduction mask) used to perform the photolithography exposure. For the purpose of performing aberration measurement, the measurement patterned device MA may be positioned on the support structure MT, for example. The measurement patterned device MA may include other features suitable for determining other properties of the projection system PS. For example, the measurement patterned device may additionally include a marker suitable for determining the alignment of the measurement patterned device with respect to the substrate table WT.

In some embodiments, the same marker can be used to determine both alignment and aberration. For example, one or more markers in the form of a reflective grating structure (such as a diffraction grating) can be used to determine both alignment and aberration. In some embodiments, the same measurement set can be used to determine both alignment and aberration at the same time.

References herein to the patterned device MA should be interpreted as including any device that includes one or more features configured to modify radiation. The patterned device MA may, for example, be provided with a pattern for use during lithography exposure (for example, the patterned device may be a reduction mask). Additionally or alternatively, the patterned device may be provided with one or more markers for use in the measurement procedure. Generally speaking, the patterned device MA is a removable component that is placed on the support structure MT to perform specific procedures (for example, performing lithographic exposure and/or performing one or more measurement procedures). However, in some embodiments, the lithography device LA itself may have one or more patterned features. For example, the support structure MT may be provided with one or more patterned features (such as markers) for use in the measurement procedure. For example, the support structure MT may be provided with one or more fiducials including one or more markers. In such embodiments, since the support structure MT has one or more features configured to modify the radiation, the support structure MT itself can be regarded as an example of a patterned device. References herein to patterned devices containing reflective markers should not be interpreted as being limited to removable patterned devices, but should be interpreted as including any device having reflective markers disposed thereon.

Referring to FIG. 1, the patterned device MA can be regarded as being arranged in the object plane of the projection system PS and the substrate W can be regarded as being arranged in the image plane of the projection system PS. In the context of this type of lithography device, the object plane of the projection system PL (where the patterned device MA is placed), the image plane of the projection system PL (where the substrate W is placed), and any plane conjugated with it can be It is called the field plane of the lithography device. It should be understood that in an optical system (such as a lithography device), if each point in the first plane P is imaged on one point in the second plane P′, the two planes are conjugated.

It should be understood that the lithography apparatus LA includes optical devices with optical power (ie, focusing and/or diverging optical devices) to form an image in the image plane of the object in the object plane. In this optical system, between each pair of field planes, it is possible to define a pupil plane as the Fourier transform plane of the previous field plane and the sequential field plane. The distribution of the electric field in each such pupil plane is the Fourier transform of the object placed in the plane of the previous field. It should be understood that the quality of this pupil plane will depend on the optical design of the system and this pupil plane may even be curved. Two such pupil planes are considered useful as the pupil plane of the illumination system and the pupil plane of the projection system. The pupil plane of the illumination system and the pupil plane of the projection system (and any other pupil planes) are mutually conjugate planes. The distribution of the intensity (or equivalently, the electric field intensity) of the radiation in the pupil plane PP _IL of the illumination system can be referred to as the illumination pattern or pupil filling and characterizing the patterning device MA (that is, in the object plane) The angular distribution of the light cone. Similarly, the intensity (or equivalently, the electric field intensity) distribution of the radiation in the pupil plane PP _IL of the projection system characterizes the angular distribution of the light cone at the wafer level (ie, in the image plane).

The illumination system IL can change the intensity distribution of the light beam in the pupil plane of the illumination system. This change can be achieved by appropriately configuring the faceted field mirror device 10 and the faceted pupil mirror device 11.

During the exposure of the substrate W, the illumination system IL and the projection system PS are used to form the (diffraction limited) image of the object-level patterned device MA on the image-level substrate W (for example, a resist-coated silicon wafer). During this type of exposure, for the lighting mode, it may be necessary to use the local lighting mode. For example, it may be necessary to use a multi-pole (e.g., dipole or quadrupole) illumination mode, where only a limited number (e.g., two or four) of discrete polar regions receive radiation in the _{pupil plane PP IL of the illumination system.} Two examples of such lighting patterns are shown in Figures 4A and 4B. For example, the illumination mode may be a dipole distribution 30 as shown in FIG. 4A or a quadrupole distribution 32 as shown in FIG. 4B. 4A and 4B also show a circle 34, which represents the limit that can be physically captured by the projection system PS and imaged onto the image plane (this represents the numerical aperture NA or the sine of the maximum angle that can be captured by the projection system PS). Among the coordinates normalized by the numerical aperture NA of the projection system PS, the circle 34 has a radius σ=1. The dipole distribution 30 contains two completely opposed pole regions 36, in which the intensity is non-zero. The quadrupole distribution 32 includes a first dipole distribution similar to the first dipole distribution shown in FIG. 4A and a second dipole distribution that is rotated by π/2 radians relative to the first dipole distribution but is otherwise the same as the first dipole distribution. Therefore, the quadrupole distribution 32 contains four polar regions 34 in which the intensity is non-zero.

When the lithography apparatus does not expose the substrate W, one of the more reflective marks provided on the patterned device MA can be used in a measurement procedure, for example, to determine the alignment and/or associated with the lithography apparatus LA Aberration. When the reflection from the marker is used to measure alignment and/or aberration, the radiation reflected from the marker may be required to fill a substantial portion of the pupil of the projection system PS. To achieve this, in principle, the illumination system IL can be reconfigured to fill the illumination system pupil plane (and therefore also the entrance pupil of the projection system). However, doing this (and returning to the exposure lighting mode before the next exposure) can take more time than this type of online measurement. Therefore, it is known to provide a diffuser during such measurements, which diffuser is configured to increase the angular spread of radiation scattered from the object-level patterned device in order to increase the incidence of a projection system PS filled with radiation The pupil ratio.

The diffuser can be placed in the path of the radiation beam during these measurement periods rather than during the exposure of the substrate W. This allows the EUV lithography device to be operable to perform semi-continuous online metrology, which in turn can be used to maintain the optimal dynamic settings of the projection system PS, the support structure MT, and the substrate table WT. In addition, such a measurement system can be used to align the patterned device MA with the substrate W before the substrate W is exposed.

Some existing measurement systems use a combined diffuser and patterned device (such as a one-dimensional diffraction grating) at the level of the object. One configuration uses a three-dimensional structure mounted on a support structure MT, which includes a concave diffuser and a grating diaphragm placed in two different planes. The radiation beam of the EUV radiation beam B leaves the illumination system IL, reflects from the concave diffuser (which increases the angular spread of the radiation), and then after reflection, passes through the grating diaphragm (its scattered radiation, some of the scattered radiation Captured by the projection system). This three-dimensional configuration cannot be formed on the reduction mask and is therefore formed on the reference member.

Another configuration as described in WO2017/207512 uses a reflective object as a combined diffuser and patterned device. This configuration has the form of a multilayer reflective stack configured to preferentially reflect EUV radiation to which a pattern of EUV absorbing material (for example, a diffraction grating) is applied. The layers of the multilayer reflective stack are provided with surface roughness to diffusely reflect radiation. However, in principle, although this type of patterned device can be provided on a reduction mask, it is significantly more complicated to fabricate a patterned device with such built-in surface roughness. Therefore, in practice, such patterned devices are more likely to be formed on the reference member.

The embodiment of the present invention relates to a novel diffuser that is particularly suitable for use with the EUV measurement system in the EUV lithography device of the type discussed above, and a method of manufacturing the same.

Figures 5A to 5C (collectively, Figure 5) schematically show the stages in the method of preparing a diffuser according to the first example. The diffuser can be constructed from multiple layers, which are referred to herein as stacks. The intermediate stacks of layers in an example program for creating a diffuser are depicted in cross-sections in FIGS. 5A to 5C. Referring to FIG. 5A, the first intermediate stack 50 includes a layer 502 of support material. For example, the support material may include silicon nitride (SiN), silicon, and molybdenum silicide (MoSi ₂ ). The support material layer 502 may have a thickness of about 10 nm to 60 nm. In some embodiments, the support material is a material having a refractive index close to 1 for EUV radiation and a relatively low absorption coefficient for EUV radiation. For such embodiments, the support material can be considered to be relatively optically neutral to EUV radiation. The supporting material layer 502 is formed on the carrier layer 504, and the carrier layer can be used to support the supporting material layer 502 while forming a diffuser. For example, the carrier layer 504 may be formed of silicon, silicon nitride (SiN), porous silicon (pSi), or molybdenum silicide (MoSi). The carrier layer 504 may, for example, have any thickness suitable for providing sufficient support during manufacturing, and in some configurations, may have a thickness of about 100 μm to 500 μm. For example, the carrier layer can be a standard silicon wafer. Alternatively, the carrier layer 504 and the support layer 502 may be provided by a single layer of the same material.

The scattering material layer 506 is provided on the support layer 502. The scattering material may be, for example, a substance such as molybdenum, ruthenium, or niobium, but may be other suitable scattering materials, as discussed in further detail below. Depending on the specific scattering material, the thickness of the scattering material layer 506 can be, for example, between approximately 50 nm and 400 nm (in the depicted z-direction).

Another layer 508 with another different metal is deposited on top of the intermediate stack 50 to form the second intermediate stack 52. For example, the other metal may be zinc (Zn). The layers 506 and 508 are processed to form an alloy layer (not shown in the figure) containing an alloy of the scattering metal and another metal (for example, a molybdenum-zinc alloy). The scattering material 506 provides the first component of the alloy, and the other metal 508 provides the second component of the alloy. For example, the layers 506, 508 can be annealed. Annealing may be performed at 400 degrees, for example. Annealing can be performed in a protective gas environment. For example, annealing can be performed in the presence of an inert gas such as argon.

The resulting alloy layer is subjected to a dealloying process to selectively corrode the second component of the alloy. For example, in the case where the second component is zinc, dealloying includes a dezincification process. Dealloying can be performed by any suitable method. For example, dealloying may include selectively dissolving zinc by immersion in acid, such as nitric acid.

After the dealloying treatment, an intermediate stack 54 is provided, which includes the porous scattering layer 510 on the support layer 502. The scattering layer 510 can be regarded as a scattering material having a plurality of voids distributed therein. The method may further include etching the carrier layer 504 from the surface opposite to the surface of the support layer supporting the porous scattering layer 510. In the case where the carrier layer 502 and the support layer 504 are separate layers, the carrier layer 502 can provide an etch stop during this backside etching process. This backside etching of the carrier layer 504 allows a thicker and more stable carrier 502 and support layer 504 to be used during manufacturing. Advantageously, this can prevent the support layer 504 from being damaged or even broken.

Optionally, the porous scattering layer 510 may contain another substance in the micropores (or voids). For example, the pores of the porous scattering layer 510 can be filled with an inert gas. Alternatively, the pores of the porous scattering layer 510 may be filled with vacuum. For example, where the scattering layer 510 is subsequently capped (discussed in more detail below), the capping can be performed in an inert gas atmosphere or in a vacuum. Alternatively, the porous scattering layer 510 can be infiltrated with optical contrast materials (for example, relatively optically neutral materials for EUV radiation, such as materials with a refractive index of or substantially close to 1) (by any suitable treatment, such as, for example, ALD, CVD). Or sputtering). This penetration of the porous scattering layer 510 can beneficially protect from degradation, protect structural integrity, and allow heat to diffuse.

Although in practice, a diffuser is likely to contain multiple layers (such as a scattering layer and a support layer), the term diffuser in this article can also refer to only the scattering layer (that is, a layer configured to diffuse incident radiation). ).

Figures 6A to 6C (collectively, Figure 6) depict another example procedure for manufacturing a diffuser suitable for EUV radiation. The intermediate stacks of layers in this example program are depicted in cross-sections in FIGS. 6A to 6C. Referring to FIG. 6A, the first intermediate stack 60 includes a support layer 602 and a carrier layer 604. The support layer 602 and the carrier layer 604 can be as described above in conjunction with the support layer 502 and the carrier layer 504 of FIGS. 5A to 5C.

The intermediate stack 60 further includes a porous layer 606 formed of a material that has been processed to form a structure. For example, the porous layer 606 may include silicon or porous silicon. The process used to create the porous layer 606 may include, for example, selective etching (eg, metal-assisted chemical etching, anodization, selective leaching).

The scattering material is deposited on the porous layer 602 to form the second intermediate stack 62 such that the scattering material at least partially occupies the micropores (or voids) in the porous layer 602 to thereby form the scattering layer 608. Depending on the scattering material used, the scattering layer 604 may have a thickness between approximately 50 nm and 1000 nm. The scattering layer 604 can be considered to provide a first substance having voids distributed therein, at least some of the voids being filled with a scattering material.

As described with respect to the previous example procedure, the method may further include etching the carrier layer 604 from the surface opposite the supporting scattering layer 604 to provide another stack 64 (which may be the final stack or may be another intermediate stack). It should be understood that in other examples discussed below, although the carrier layer is not depicted, the carrier layer may be provided and the carrier layer may be etched after the scattering layer has been provided on the support structure.

In addition, in all the examples described herein, in addition to the layers shown in FIGS. 5 and 6, additional layers may be provided. For example, referring to FIG. 5 as an example, another layer may be provided between the supporting layer 502 and the scattering layer 510 or between the carrier layer 504 and the supporting layer 502. This additional layer can beneficially provide additional protection to the scattering layer during use, especially from the particles present inside the lithography device. Similarly, an additional (or "cap") layer can be provided on top of the scattering layer 510 for the same purpose. Such additional layers may have a thickness of about 10 nm. This additional layer formed forms a metal oxide or metal nitrate. For example, additional layers can be provided from silicon nitride or molybdenum silicide.

Figures 7A to 7E (collectively, Figure 7) depict another example procedure for manufacturing a diffuser suitable for EUV radiation. In the example of FIG. 7, a non-uniform scattering material layer is deposited on a random or random arrangement of the structure (such as guide posts on the surface of the support layer or holes in the surface of the support layer). The structure can be provided according to any suitable technology. For example and as depicted in Figure 7, the structure can be provided via nanoparticle lithography. Alternatively, normal (eg, resist) lithography using pseudo-random masks, selective leaching for dealloying, random deposition of metal catalyst particles for metal-assisted chemical etching, etc. can be used to create structures.

In the example depicted in FIG. 7, the intermediate stack 70 includes a support layer 702. For example, the support layer 702 can take the same or similar form as the support layers 502 and 602 described above with reference to FIGS. 5 and 6. Although not depicted in FIG. 7, it should be understood that the intermediate stack 70 may include a carrier layer, which may take the same or similar form as the carrier layers 504, 604 described above.

The nanoparticle layer 704 is deposited on the support layer 702 in a random or random distribution. The particles in layer 704 may be formed of polystyrene particles. Alternatively, the particles in layer 704 may be formed of another material suitable for nanosphere lithography, such as latex or silica, cellulose, or the like. In the example depicted in FIG. 7A, the particles in layer 704 are polydisperse, including a plurality of particles with different size ranges. Specifically, for example, the diameter of some particles 704 may be smaller than the diameter of other particles 704. As an example, the particles may have a diameter in the range of 20 nm to 300 nm. The particles have a random distribution of the displacements of neighboring particles. The particles in layer 704 may take the form of balls. The particles can be applied to the support layer 702 in any suitable manner. For example, a vertical deposition procedure from a colloid containing particles can be used to apply the particles. For example, a Langmuir-Blodgett deposition process can be used, such as Langmuir (20042041524-1526, December 25, 2003, https://doi.org/10.1021/la035686y). Described in. The vertical deposition process is suitable for providing a single layer of polystyrene particles. It should be understood, however, that the deposition can be according to any method that can be adapted to produce a single layer or a few layers. For example, the deposition can be by means of spin coating or inkjet particles in a solvent. The particles may be spherical or substantially spherical (e.g., the particles may be ellipsoids). However, the particles can have other shapes.

As depicted in FIG. 7B, the particles in layer 704 can be shrunk to provide a second intermediate stack 72. The shrinkage of particles in layer 704 is an optional step and can be beneficial to further expose the area of support layer 702, thereby allowing adjustment of the dimensions (size, pitch, density) of the structure created, as described in more detail below. For example, reactive ion etching (RIE) can be used to process the particles, which causes each of the particles in layer 704 to shrink.

Regardless of whether the particles in the layer 704 shrink or not, the particles in the layer 704 can operate to provide a mask on the surface of the support layer 702. It should be understood that the arrangement of particles on the surface is random or random, and the mask provided by these particles will also be random or random.

The catalyst is deposited on the surface of the support layer 702 adjacent to the particle layer 704, so that the portion of the surface that is not shielded by the particles is coated with the catalyst deposit 712. The catalyst may be a metal catalyst, such as gold or platinum. The particles in the layer 704 are removed, and the surface of the support layer 702 on which the catalyst is deposited is selectively etched to form the modified support material layer 714 and the third intermediate stack 74. In fact, the part of the support layer 702 in contact with the catalyst deposit 712 is etched to create a plurality of structures (or features) on the surface of the support material in contact with the catalyst. This type of metal-assisted catalytic etching is also a known and robust procedure. The structure in this example includes a plurality of cavities or pits with corresponding peaks or guide posts.

In the alternative, a procedure may be used to deposit the mask on the support layer 704 between the particles and the surface of the support layer etched in those areas not protected by the mask. In the case where the procedure depicted in Figure 7 creates a cavity in the area under the catalyst, this alternative procedure can be thought of as creating a guide post in the area under the protective mask. As known to those skilled in the art, any suitable mask material and etching process can be used.

After the modified support structure 714 is created, the catalyst or mask can be removed to provide the fourth intermediate stack 76, but it should be understood that this is an optional step.

The scattering material 716 can then be deposited onto the modified support structure 714, which is formed in and around the structure provided on the surface of the modified support structure 714 to provide another stack 78 (which can be the final stack or can be Another middle stack). Due to the structure present on the modified support structure 714, the scattering material 716 acts as a microlens array, causing the EUV radiation incident on the diffuser created from it to scatter. Lens formation (partly) is the result of shadows caused by the presence of the structure. Therefore, the shadow can be increased by directing the particle flow of the scattering material 716 at an angle other than 90 degrees to the surface of the substrate.

It is not depicted, but as in the previous example and where a carrier layer is provided, the carrier layer can be back-etched. Additionally or alternatively, a portion of the support structure 714 may be etched, particularly from the surface opposite to the surface on which the scattering material 716 is deposited, to provide a diffuser.

Figures 8A to 8D (collectively, Figure 8) depict another example procedure for manufacturing a diffuser suitable for EUV radiation. Figure 8A depicts a first intermediate stack 80 that includes a support layer 802 on which a polydisperse monolayer of nanoparticles 804 is deposited. The nanoparticles in layer 804 can be the same as discussed above with respect to the nanoparticles in layer 704, and can be deposited by any procedure. For example, the nanoparticles 704 can be formed of polystyrene and can be deposited on the support layer 802 in a random or pseudo-random distribution using a vertical deposition process.

The second intermediate stack 82 is created by depositing the scattering material layer 806 on the support layer 802 between the nanoparticles 804. For example, the scattering material layer 806 may be deposited by means of electrodeposition. In this way, the nano particles 804 form a mask on the support layer 802 so that the scattering material 806 is formed in the gaps around the particles 804 to provide a non-uniform scattering material layer. The nano-particles 804 may be shrunk before the deposition of the scattering layer as appropriate, so as to change the pitch between the nano-particles and expose more support layer 802.

Optionally remove the nanoparticles 804 to provide a third stack 84. The third stack 84 can be used to provide a diffuser (e.g., after any required backside etching of the carrier layer (not shown)). It should be understood that the scattering material 806 forms an undulating or wavy structure on the supporting layer 802. The wave structure is defined by peaks and valleys, wherein the pitch between adjacent peaks is defined by the size of the nanoparticle or particles 804 separating the peaks during the manufacture of the diffuser. Similarly, the depth of the valley (that is, in the propagation direction of the radiation beam) is defined by the shape and depth of the nanoparticle 804 and the depth to which the scattering material layer 806 is deposited around the nanoparticle 804 (which may depend on the desired scattering/ The attenuation properties and the specific scattering materials used vary).

The fluctuation will match the distribution of the nanoparticle 804, so that the fluctuation can be randomly or randomly distributed across the scattering layer and have a plurality of different ranges in each dimension. For example, some of the peaks may have a different range in any of the x, y, or z directions from the others of the peaks, and any pair of adjacent peaks (at The x or y direction) may be different from the pitch between any other pair of adjacent peaks. In addition, it should be understood that due to the different sizes of the nanoparticle 804, the ripples will have different curvatures (for example, the ripples will have different gradients).

In addition, an optional second scattering material layer can be provided, as depicted in FIG. 8D. In this example, an intermediate layer 808 is deposited on top of the scattering layer 806 to create another intermediate stack 86. The intermediate layer 808 may be formed of a material that is relatively optically neutral to EUV radiation (for example, has a refractive index close to 1 for EUV radiation and has a relatively low absorption coefficient for EUV radiation). For example, the intermediate layer 808 may be formed of silicon. The intermediate layer 808 may have a thickness in the range of 30 nm to 400 nm, and preferably in the range of 30 nm to 150 nm. The procedures depicted in FIGS. 8A to 8C can then be repeated to form the second scattering layer 810 on the intermediate layer 808. It should be understood that the second scattering layer will provide additional scattering of incident EUV radiation when used as a diffuser, and will help prevent or reduce zero-order scattering.

Figures 9A-9E (collectively, Figure 9) depict another example procedure for manufacturing a diffuser suitable for EUV radiation. As shown in FIG. 9A, the first intermediate stack 90 takes the same form as the intermediate stack 80 in FIG. 8A, with the nanoparticle layer 904 deposited on top of the support layer 902. Similar to the procedure depicted in FIG. 8, the first scattering layer 906 is deposited on the support layer 902 between the nanoparticles 904. In contrast to the method depicted in Figure 8, the second intermediate stack 92 is created by depositing an intermediate (or sacrificial) layer 908 between the first scattering layer 906 and the other scattering layer 910 (Figure 9B). The intermediate layer 908 may be formed of a material suitable for selective etching or any other removal process that makes the remaining components of the stack undamaged.

The third intermediate stack 94 is created by removing the nanoparticles 904, leaving cavities in the layers 906, 908, 910 (Figure 9C). Nanoparticles 904 can be removed by any suitable technique in the field sometimes referred to as "nanoparticle lithography", and indeed any other suitable technique as will be obvious to those familiar with this technique. Merely as an example, the nanoparticle 904 can be removed via heating. The fourth intermediate stack 96 is created by filling the cavity with a material that is relatively optically neutral to EUV radiation (Figure 9D). For example, the cavities can be filled with silicon (e.g., through a silicon infiltration process using liquid silicon, through deposition of silicon (some of which will fill some of the cavities), or through any other suitable method). The material in the cavity thereby forms an intermediate support structure 912 above the scattering layer 906 to support the scattering layer 910.

The fifth stack 98 is created by removing the middle layer 908 (Figure 9E). For example, the intermediate layer 908 can be removed by etching. The stack 98 thereby includes two scattering layers 906, 910 separated and supported by a relatively sparse intermediate support structure 912 (i.e., separated particles). As in the previous example, the procedure of FIG. 9 can be repeated to create additional layers on top of the scattering layer 910.

In an alternative configuration, the nanoparticles 904 may be made of silicon, for example. In this case, there is no need to remove the nanoparticles before removing the sacrificial layer. In another alternative configuration, both the nanoparticle and the sacrificial layer may be formed of silicon. In this situation, the stack 92 depicted in FIG. 9B can be considered the final stack and can be used to provide a diffuser (after any other required processing such as backside etching or deposition of the capping layer). That is, in some configurations, the combination of layers 910, 908, 906 and nanoparticle 904 can together provide the scattering layer of the diffuser.

Figures 10A to 10E schematically depict another example program for creating a diffuser suitable for EUV radiation. In Fig. 10A, an intermediate stack 100 is shown. The intermediate stack 100 includes a support layer 1002 on which a nanoparticle layer 1004 is deposited. The intermediate stack 100 can be an intermediate stack 70, 80, 90 and can be generated from the intermediate stack 70, 80, 90.

The second intermediate stack 102 is created by depositing a relatively optically neutral material (such as silicon) on the surface between the nanoparticles 1004 and the surrounding nanoparticles 1004. The top portion of at least some of the nanoparticles remains above the highest level of the optically neutral material. The optically neutral material thereby forms the filler layer 1006. Optionally, the nanoparticle 1004 may be processed before the filler layer 1006 is deposited to shrink the nanoparticle 1004 to further expose the part of the support layer 1002.

The third intermediate stack 104 is created by removing the nanoparticles to leave pits or cavities in the filler layer 1006. The nanoparticle 1004 can be removed according to any suitable technique as described above and will depend on its composition.

The fourth stack 106 is created by filling the cavity in the filler layer 1006 with a scattering material to form a plurality of scattering particles 1008 in the filler layer. The fourth stack 106 can be used to provide a diffuser (e.g., after any required backside etching of the carrier layer and/or support layer 1002). Alternatively, the fourth stack 106 may be an intermediate stack, and may be formed by depositing another layer 1010 with a relatively optically neutral material (which may be the same as the material (such as silicon) used for the filler layer 1006, or may be different) Create another intermediate stack 108. The other layer 1010 provides support to create another scattering layer (for example, using the procedure illustrated in FIGS. 10A to 10D, or another procedure taught herein or elsewhere).

Figures 11A-11C (collectively, Figure 11) depict another example procedure for creating a diffuser suitable for EUV radiation. In FIG. 11A, the intermediate stack 110 includes a support layer 1102 on which a random or random multilayer deposit of polydisperse nanoparticles 1104 (such as polystyrene particles) is provided. The multilayer deposits of nanoparticles 1104 can be provided on the support layer 1102 in any suitable manner described herein, such as by vertical colloidal deposition. Within the volume occupied by the nanoparticle 1104, the nanoparticle may have a packing density of about 60% to 70%. That is, for the volume occupied by nano particles, 60% to 70% of the volume can be occupied by nano particles, and the remaining 30% to 40% are voids.

The second intermediate stack 112 is created by penetrating the gaps between the nanoparticles 1104 with the scattering material 1106. The scattering material 1106 can be provided according to any suitable method. Example methods for providing the scattering material 1106 include atomic laser deposition (ALD) and electrodeposition (e.g., Fabrication and optical characterization of polystyrene opal templates for the synthesis of scalable , nanoporous ( photo ) electrocatalytic materials by electrodeposition (J. Mater. Chem. A, described in May 2017, 11601-11614).

Optionally, the third stack 114 is created by removing the nanoparticles 1104 to leave voids 1108 in the scattering material 1106. For example, the nanoparticles can be removed by heating the second stack 112 at a temperature sufficiently high (eg, 500 degrees) to evaporate the nanoparticles. In the example processes illustrated in Figures 7-11, nanoparticles are used to create scattering structures/layers. At an intermediate stage in the manufacturing process, the nanoparticles can be removed. For example, when the nanoparticles are polystyrene particles, the nanoparticles can be removed by heating and evaporation. As indicated above, other types of nanoparticles can be used instead of polystyrene, such as silica, cellulose, etc., which can also be removed by evaporation. As an alternative, titanium oxide (TiO ₂ ) nanoparticles can also be used, and the titanium oxide nanoparticles can be removed by, for example, selective etching.

In some example programs, the nanoparticles may not be removed.

Nanoparticles can be made of materials other than polystyrene. In another example, the nanoparticles can be made of materials that are relatively optically neutral to EUV radiation, such as silicon. In the case where the nanoparticles are made of, for example, silicon (or another optically neutral material or a material that provides the opposite refractive index compared to the scattering material 1106), it may be beneficial to retain the nanoparticles for final diffusion Device. This provides another benefit of requiring fewer processing steps.

More generally, in the above example, a multilayer stack of materials is created to provide a diffuser suitable for EUV. Those familiar with the art should understand that the method of creating a specific material layer (such as a scattering layer, an intermediate layer, a particle layer, and such as aerosol deposition, vertical deposition, electrodeposition, etc.) described in the context of an example can be used in Used in any other instance. In addition, the embodiments described above provide methods for creating scattering surfaces or structures in a multilayer stack. It should be understood that any or more of the procedures set forth above can be combined to form a multilayer stack with multiple scattering layers or structures. For example, the scattering layer as described with reference to FIG. 8C may be provided on top of the porous scattering structure 510 as described with reference to FIG. 5. Any other combinations of scattering layers are possible and should be understood to be within the scope of the present invention.

In addition, although different layers are often described as having different thicknesses, it should be understood that their thicknesses can vary depending on the materials used in that layer and the desired optical interaction (if any) of that layer with incident EUV radiation. However, in general, in each instance, the diffuser layer (or scattering layer, that is, those layers configured to scatter incident EUV radiation) may have approximately 100 nm and 1000 nm along the propagation direction of the received radiation The total combined thickness between.

It should be understood that diffusers manufactured according to the procedures described herein will be transmissive diffusers for EUV radiation. Generally speaking, in order to maximize the intensity of EUV radiation output by the diffuser, it is necessary to minimize the attenuation caused by the scattering material layer. This can be done by minimizing the extinction coefficient of the scattering material and/or minimizing the thickness of the scattering material. In addition, it should be understood that for a given scattering material, in order to increase the amount of angular dispersion, the thickness of the layer needs to be increased, and in order to reduce the attenuation caused by the scattering material, the thickness of the layer needs to be reduced. Scattering materials with a larger magnitude of (1-n) allow for reduced thickness (while still providing reasonable angular dispersion). Having a scattering material with a small extinction coefficient k for EUV radiation allows for increased thickness (while still providing reasonable transmission).

Suitable materials for the scattering material layer include: molybdenum, ruthenium, yttrium, rhodium, tectonium or niobium. Figure 13 shows a plot of the extinction coefficient k for EUV radiation for some of these three materials and for carbon and silicon versus the magnitude of (1-n) for EUV radiation.

As already stated, it is necessary to maximize the (1-n) value of the scattering material for EUV radiation. In some embodiments, the amount of (1-n) of the scattering material for EUV radiation may be greater than the threshold 0.06 (that is, to the right of the line 60 in FIG. 13). In some embodiments, the (1-n) value of the scattering material for EUV radiation may be greater than the threshold 0.08 (that is, the right side of the line 62 in FIG. 13). In some embodiments, the amount of (1-n) of the scattering material for EUV radiation may be greater than the threshold value 0.1 (that is, to the right of the line 64 in FIG. 13). In some embodiments, the amount of (1-n) of the scattering material for EUV radiation may be greater than the threshold value of 0.12 (that is, to the right of the line 66 in FIG. 13).

As already stated, it is necessary to minimize the extinction coefficient k of the scattering material for EUV radiation. In some embodiments, the scattering material may have ^{an extinction coefficient k less than the threshold 0.04 nm- 1} (ie, below the line 70 in FIG. 13) for EUV radiation. In some embodiments, the scattering material may have an extinction coefficient k for EUV radiation that is less than the threshold 0.03 nm ^{- 1} (that is, below the line 72 in FIG. 13). In some embodiments, the scattering material may have ^{an extinction coefficient k less than the threshold value of 0.02 nm- 1} (that is, below the line 74 in FIG. 13) for EUV radiation. In some embodiments, the scattering material may have an extinction coefficient k for EUV radiation that is less than a threshold value of 0.01 nm ^{- 1} (that is, below the line 76 in FIG. 13 ).

It should be understood that for a given scattering material, in order to increase the amount of angular dispersion, the thickness of the layer needs to be increased, and in order to reduce the attenuation caused by the scattering material, the thickness of the layer needs to be reduced. Scattering materials with a large magnitude of (1-n) allow for reduced thickness (while still providing reasonable angular dispersion). Having a scattering material with a small extinction coefficient k for EUV radiation allows for increased thickness (while still providing reasonable transmission). Therefore, it should be understood that in practice, suitable materials that balance these two requirements can be selected.

In some embodiments, the magnitude of (1-n) is greater than the threshold 0.06 and the magnitude of the extinction coefficient k for EUV radiation is less than the threshold 0.01 nm ^{- 1} ; or the magnitude of (1-n) is greater than the threshold The limit value is 0.08 and the value of the extinction coefficient k for EUV radiation is less than the threshold value of 0.02 nm ^{- 1} ; or the value of (1-n) is greater than the threshold value of 0.1 and the value of the extinction coefficient k for EUV radiation is less than the threshold value. The limit value is 0.03 nm ^{- 1} ; or the value of (1-n) is greater than the threshold value of 0.12 and the value of the extinction coefficient k for EUV radiation is less than the threshold value of 0.04 nm ^{- 1} . That is, material can be found in the cross-hatched area in FIG. 13.

In some embodiments, the magnitude of (1-n) and the extinction coefficient k for EUV radiation satisfy the following relationship:

Where |1-n| is the magnitude of (1-n). This is equivalent to being below line 80 in FIG. 13.

The embodiments described herein provide one or more layers of scattering materials (referred to herein as scattering layers, scattering structures, etc.) that cause scattering and have nanostructures formed thereon or in them. The layer (or layers) of the scattering material can act as a random array of microlenses, thereby causing the EUV radiation incident on the diffuser including the scattering layer to be scattered. This is particularly advantageous for EUV radiation (which may have a wavelength of 13.5 nm, for example), because such nanostructures contain features that are equivalent to or smaller than the wavelength of the radiation that needs to be diffused. Under these conditions, the scattering is in the Mie-scattering system, and significant angular dispersion can be achieved. For example, in some embodiments, the nanostructure formed in the scattering material layer includes features with a size in the range of 2 nm to 220 nm.

FIG. 12 schematically shows the diffuser 120. The diffuser 120 contains the residue of the carrier layer 1202 that has been back etched to allow radiation to pass through the diffuser 120. In other embodiments, the entire carrier layer may have been back-etched. The diffuser 120 further includes a support layer 1204 and a cover layer 1206. The scattering layer 1208 is between the support layer 1204 and the cover layer 1206. In the depicted example, the scattering layer 1208 takes the form of the scattering layer 1106 of FIG. 11C, but it should be understood that the scattering layer 1208 can take any form as described herein. In use, radiation 1210 is incident on the diffuser 120 and propagates generally in the z-direction depicted. This incident radiation 1210 may correspond to the radiation beam B output by the illumination system IL. It should be understood that the incident radiation may include radiation having different ranges of incident angles, and the arrow 1210 shown in FIG. 12 may indicate the direction of the chief ray. The scattering layer 1208 makes the incident radiation spread in a larger angle range. This is indicated schematically by arrow 1212.

。對於一些應用，諸如在偶極照明(如圖4A中所描繪)之狀況下，可較佳的是提供漫散器以使得輻射1210之發散度為大約

度以提供大體上完整的光瞳填充。在另一實施例中，微影裝置中之圖案化器件MA (及投影系統PS)之數值孔徑可能高於0.08，例如，0.16弧度之數值孔徑對應於大致9°之角度範圍。In use, the diffuser 120 can be used to increase the angle range, and the radiation having the angle range reflected from the object level marker enters the projection system PS. In particular, it may be necessary to cause each part of the diffuser 120 to cause the radiation 1210 to diverge, which is approximately the angular range of the radiation received by the patterned device MA in the lithography apparatus LA. For example, in one embodiment, the numerical aperture of the patterned device MA (and the projection system PS) in the lithography apparatus may be approximately 0.08, which corresponds to an angular range of approximately 7°. Therefore, it may be necessary to make the divergence of the radiation 1210 caused by the microlens provided by the scattering layer 1208 to be about 7°. This can ensure that each field point on the patterned device MA receives radiation from substantially the entire angular range within the cone having a complete angular range of about 7°. Equivalently, this ensures that the patterned device fills the illumination with a substantially complete pupil

. For some applications, such as in the case of dipole illumination (as depicted in Figure 4A), it may be better to provide a diffuser so that the divergence of the radiation 1210 is approximately

Degree to provide substantially complete pupil filling. In another embodiment, the numerical aperture of the patterned device MA (and the projection system PS) in the lithography apparatus may be higher than 0.08. For example, a numerical aperture of 0.16 radians corresponds to an angular range of approximately 9°.

In some embodiments, the diffuser 120 may have a thickness (in the z-direction in FIG. 12) that is configured to cause EUV radiation 1210 propagating across the thickness of the diffuser 120 to be (2m +1) Phase shift of π radians. Advantageously, this suppresses zero-order (or specular) scattering.

Table 1 below lists a variety of example materials that can be used as scattering materials. In Table 1, n is the refractive index of radiation with a wavelength of 13.5 nm (such as EUV radiation), k is the extinction coefficient of the material for radiation with a wavelength of 13.5 nm, and Lt indicates that the incident radiation will attenuate no more than 90 % Of the maximum thickness of the layer of that material (in the propagation direction of the radiation), and Lr is the minimum thickness of the layer of that material that is required for the phase shift of pi radians. The row Lr / Lt is the ratio indicating the balance between the diffuse potential and the attenuation of each material. n k Lt Lr Lr/Lt @13.5 nm @13.5 nm 10% transmission nm II phase shift nm Ce 1.0065 0.0062 398 6707 16.9 Si 0.9970 0.0018 1374 6750 4.9 La 0.9974 0.0050 494 2596 5.3 Y 0.9738 0.0023 1075 257 0.2 SiO ₂ 0.978 0.011 224 306 1.4 SiN ₄ 0.973 0.009 274 250 0.9 B 0.9719 0.0036 687 240 0.3 MoSi ₂ 0.97 0.004 610 240 0.4 Y ₂ O ₃ 0.9620 0.01 247 177 0.7 C 0.9616 0.0069 358 175 0.5 Zr 0.9589 0.0038 650 164 0.3 Ti 0.9519 0.0142 174 140 0.8 ZrO ₂ 0.9464 0.015 164 125 0.8 MoO ₂ 0.9343 0.017 145 102 0.7 Nb 0.9337 0.0052 475 101 0.2 Mo 0.9233 0.0065 380 88 0.2 Ru 0.8864 0.0171 144 59 0.4 Table 1

It can be seen from Table 1 that there are a variety of materials that will provide sufficient transmission and sufficient scattering for a specific material thickness. In particular, those materials whose ratio Lr / Lt is less than 1 can be considered to provide suitable candidates. A lower Lr / Lt ratio may indicate a better material, but it should be understood that other considerations may apply, such as ease of work, source of raw materials, long life, etc.

As described above, some examples include diffusers that include a plurality of scattering layers, each layer being configured to differently change the angular distribution of EUV radiation passing through it. Advantageously, by providing a plurality of layers, each layer is configured to differently change the angular distribution of EUV radiation passing through it, and the diffuser provides a configuration whereby the EUV radiation beam can be diffused more effectively across the desired angular range. In addition, multiple layers that differently change the angular distribution of EUV radiation passing through them provide more control over the angular distribution of radiation leaving the diffuser.

Figures 14A to 14C depict another example procedure for manufacturing a diffuser suitable for EUV radiation. The intermediate stacks of layers in this example program are depicted in cross-sections in FIGS. 14A to 14C. The first intermediate stack 140 includes a support layer 1402. For example, the support layer 1402 can take the same or similar form as the support layers 502 and 602 described above with reference to FIGS. 5 and 6. Although not depicted in FIG. 14, it should be understood that the intermediate stack 70 may include a carrier layer, which may take the same or similar form as the carrier layers 504, 604 described above.

The random or random multilayer deposits of the particles 1406 are provided to the support layer 1402 in any suitable manner previously described herein, such as by vertical colloidal deposition. The particles are polydisperse. Each particle of the multilayer deposit of particles 1406 is in contact with one or more neighboring particles such that a gap 1408 is formed between the neighboring particles. The multilayer deposit of particles 1406 can be considered to form a particle body 1406. The particles in the particle body 1406 can be referred to as contact particles because each particle is in contact with one or more neighboring particles.

The particle body 1406 includes a first particle group 1406A with a first material and a second particle group 1406B with a second material, and can be called a binary mixture of particles. The two materials are scattering materials, examples of which are discussed in more detail with reference to FIG. 13 and Table 1. In particular, the first and second materials are selected to have different refractive indexes. The composition of the binary mixture (that is, the composition of the first particle group 1406A and the second particle group 1406B) is selected based on the desired attributes of the diffuser. Example binary mixtures include silicon and molybdenum, ruthenium and silicon, molybdenum silicide and silicon.

In addition to the composition of the particles 1406A and 1406B, other characteristics of the particle body 1406 can also be selected based on the desired optical properties of the diffuser. For example, the angular distribution of the scattering of radiation through the diffuser depends on the particle size, particle size distribution, and packing density. By changing the composition, particle size, particle size distribution and/or packing density, properties such as scattering angle, suppression of zero-order scattering, emissivity and attenuation. Within the volume occupied by the particle body 1406, the particles 1406A, 1406B may have a packing density of about 60% to 70%. That is, for the volume occupied by the particles, 60% to 70% of the volume can be occupied by the particles 1406A, 1406B, and the remaining 30% to 40% is empty (that is, contains the void 1408).

In the second intermediate stack 142, the particle body 1406 is fixed in place by, for example, fusing the particles to form a fused particle body 1014. The process for fixing the particles 1406 may include providing heat and/or pressure. Specifically, sintering can be used to fix the particles, such as laser flash sintering, spark plasma sintering, or spark sintering. Other fixing methods are available. Fixing the particles in place can be performed as part of the deposition process or as a separate procedure.

In the third intermediate stack 144, a protective layer is provided on top of the fused particle body 1410. The protective layer can provide protection for the scattering layer (that is, the fused particle body 1410) in use (for example, in the environment of the lithography device). Additionally or alternatively, the protective layer may provide increased emissivity to the diffuser.

15A to 15C illustrate an example diffuser manufactured according to the procedure described with reference to FIGS. 14A to 14C, and the performance of the diffuser. Specifically, the particles include molybdenum silicide and silicon (MoSi and Si) and are polydisperse with a radius between 75 nm and 85 nm. The particles are deposited in a random distribution. Approximately six particle layers are deposited on the support layer.

FIG. 15A depicts a height map 1500 of the obtained particle body. The height map 1500 omits the support layer, but the particle body will be supported by the support layer in use.

Figures 15B and 15C depict the scattering angle of the plane wave for EUV radiation incident on the example diffuser. In particular, Figures 15B and 15C cooperate to illustrate the beam profile of scattered EUV radiation, wherein Figure 15B depicts the intensity of the scattered EUV radiation across a range of angles in a plane orthogonal to the direction of travel of the scattered EUV radiation, and Figure 15C depicts The cross-sectional representation of the beam profile. EUV radiation undergoes scattering at a wide angle range up to 40°. EUV radiation undergoes scattering with a relatively constant intensity within an angular distribution of approximately 10°. Thus, this example diffuser can provide an effective diffuser for high numerical aperture patterned devices.

Figures 16A and 16B depict another example procedure for manufacturing a diffuser suitable for EUV radiation. Specifically, the diffuser in FIGS. 16A and 16B is a holographic diffuser suitable for EUV radiation. The middle stack 160, 162 in this example program is depicted in cross section.

The first intermediate stack 160 includes a support layer 1602. For example, the supporting layer 1602 can take the same or similar form as the supporting layers 502 and 602 described above with reference to FIGS. 5 and 6. Although not depicted in FIGS. 16A and 16B, it should be understood that the intermediate stack 70 may include a carrier layer, which may take the same or similar form as the carrier layers 504, 604 described above.

The structure 1604 is provided on top of the supporting layer 1602. The structures 1604 can be provided according to any suitable technology. For example and as depicted in Figure 16, an electron beam mask may be used to provide structure 1604 via photolithography. Alternatively, electron beam lithography or nanoimprint lithography, etc. can be used to create such structures.

A void 1605 is formed between the structures 1604. That is, in the volume of space occupied by the structure 1604, there is a volume that does not contain the structure and therefore contains the void 1605.

The structure 1604 (and therefore the void 1605) is configured in a holographic interference pattern such that when illuminated by radiation, the radiation is diffracted to form a holographic image. Select the structure configuration so that the desired holographic image is produced. The holographic image can be generated at the input plane of the measurement system (such as the measurement system described above).

In an example configuration, a holographic interference pattern is selected to form a holographic image with a substantially constant angular profile (that is, an angular intensity profile) across a selected angular distribution (for example, 10°). A generally constant angular profile may be referred to as a top hat profile. In another example configuration, the holographic interference pattern is selected so as to form a holographic image whose angular profile is stronger in the radially outer part of the holographic image than in the radially inner part of the holographic image. That is, the holographic diffuser diffuses EUV radiation so that light is scattered with higher intensity for larger scattering angles.

。判定厚度剖面

之方法在下文進一步更詳細地加以描述。The structure 1604 is configured on the plane of the support layer 1602 in a specific configuration (for example, in the xy plane). Each part of each structure 1604 has a height that extends from the supporting layer 1602. This height can be referred to as the thickness of the portion of the structure 1604. The configuration of the structure 1604 on the support layer 1602 includes the combination of the position and thickness of each structure 1604 on the support layer 1602, and can be called the thickness profile of the holographic interference pattern

. Determine the thickness profile

The method is further described in more detail below.

The second intermediate stack 162 depicts the step of providing a filling layer 1606 on top of the supporting layer 1602 and/or structure 1604. The filling layer 1606 can be provided according to any suitable technique, such as atomic laser deposition (ALD) or electrodeposition.

A filling layer 1606 is provided to fill the volume that previously contained voids 1605 (e.g., as shown in Figure 16A). The filling layer 1606 has a thickness such that the combined thickness of the structure 1604 and the filling layer 1606 in the z direction (that is, extending from the supporting structure 1604) is substantially constant. The filling layer 1606 can be considered to adjust the structure to provide a smooth surface (e.g., substantially smooth on the microscale or nanoscale).

)相比具有折射率之不同實數部分(

)的材料。The filling layer 1606 includes a material having a refractive index different from that of the structure 1604. In particular, the filling layer 1606 includes the real part of the refractive index of the structure 1604 (

) Compared to the different real part with refractive index (

)s material.

、

以量化通過層1606及結構1604之折射率之實數部分

、

偏離1的量。當填補層1606及結構1604組合成薄層(如圖16B中所描繪)時，該薄層具有使用方程式(2)來近似之折射率的有效實數部分

。為簡單起見，折射率之有效實數部分可被簡單地稱作有效折射率。

Differential refractive index can be used

,

To quantify the real part of the refractive index passing through the layer 1606 and the structure 1604

,

The amount deviated from 1. When the filling layer 1606 and the structure 1604 are combined into a thin layer (as depicted in FIG. 16B), the thin layer has an effective real part of the refractive index approximated by equation (2)

. For simplicity, the effective real part of the refractive index can be simply referred to as the effective refractive index.

、

影響輻射之折射，且因此控制漫散器之散射屬性。選擇填補層1606使得其之折射率之實數部分

高於結構1604之折射率之實數部分

。Real part of refractive index

,

Affect the refraction of radiation, and therefore control the scattering properties of the diffuser. The filling layer 1606 is selected so that the real part of its refractive index

Real part higher than the refractive index of structure 1604

.

)相比具有折射率之相似虛數部分(

)的材料。當將填補層1606及結構1604組合成薄層(如圖16B中所描繪)時，該薄層具有使用方程式(3)所近似之折射率的有效虛數部分

。

The filling layer 1606 further includes an imaginary part similar to the refractive index of the structure 1604 (

) Compared to the similar imaginary part with refractive index (

)s material. When the filling layer 1606 and the structure 1604 are combined into a thin layer (as depicted in FIG. 16B), the thin layer has an effective imaginary part of the refractive index approximated by equation (3)

.

影響漫散器之衰減。因而，藉由向填補層1606及結構1604提供折射率之相似虛數部分，其各自具有可相當的衰減。Effective imaginary part of refractive index

Affect the attenuation of the diffuser. Therefore, by providing the filling layer 1606 and the structure 1604 with similar imaginary parts of the refractive index, they each have a comparable attenuation.

Equation (4) can be used to approximate the effective layer thickness L of the thin layer.

的區域時，經歷為pi (π)之相移。當輻射穿過漫散器之其中填補層1606之厚度為L 且結構1604之厚度為零(0)的區域時，經歷為兩個pi (2π)之相移。藉由將填補層1606及結構1604之厚度限制為

之倍數，可將相移控制為pi (π)相移之倍數，藉此提供受控之相位調變。將此類受控厚度用於全像漫散器中可被稱作二元相位調變或三元相位調變。The radiation traveling through the diffuser undergoes phase shift and attenuation based on the thickness of each of the filling layer 1606 and the structure 1604 at the location of the diffuser through which the radiation travels. When the radiation passes through the region of the diffuser where the thickness of the filling layer 1606 is zero (0) and the thickness of the structure 1604 is L , it experiences a phase shift of zero (0). When the radiation passes through the diffuser, the filling layer 1606 and the structure 1604 each have a thickness

In the region of, experience a phase shift of pi (π). When the radiation passes through the region of the diffuser where the thickness of the filling layer 1606 is L and the thickness of the structure 1604 is zero (0), it experiences a phase shift of two pi (2π). By limiting the thickness of the filling layer 1606 and the structure 1604 to

The phase shift can be controlled as a multiple of pi (π) phase shift, thereby providing controlled phase modulation. The use of such a controlled thickness in a holographic diffuser can be referred to as binary phase modulation or ternary phase modulation.

It should be noted that the holographic diffuser as described herein uses controlled phase modulation due to the controlled choice of thickness and configuration within the scattering layer. This is in contrast to other diffusers described in this article, such as the diffuser described with reference to FIGS. 14A to 14C, which uses random phase due to the random arrangement of the nanoparticles in the scattering layer Modulation.

The thickness of the filling layer 1606 and the part of the structure 1604 may be further limited to a minimum thickness, such as 50 nm or 0 nm, based on manufacturing constraints, for example. The thickness of the filling layer 1606 and the part of the structure 1604 can be further limited to a maximum thickness, such as 200 nm, for example to limit attenuation.

平面的平面中延伸之薄漫散層，可根據方程式(5)近似通過漫散層對光之散射。

An example method for determining the configuration and thickness of the structure 1604 is as follows. Consider expressing

The thin diffuser layer extending in the plane of the plane can approximate light scattering by the diffuser layer according to equation (5).

量化由行進通過漫散層之特定位置(在x 及y 中)的具有波長

的輻射射線所經歷之散射角。所計算之光之散射

可被稱作角度剖面

。漫散層具有表示漫散層在x 及y 中之每一位置處之有效厚度的厚度剖面

。

表示漫散層之折射率之實數部分與1的偏差，且k為折射率之虛數部分。

Quantify the wavelength that travels through a specific position (in x and y ) of the diffuse layer

The scattering angle experienced by the radiation rays. Calculated light scattering

Can be called angular profile

. The diffuse layer has a thickness profile representing the effective thickness of the diffuse layer at each position in x and y

.

It represents the deviation of the real part of the refractive index of the diffuse layer from 1, and k is the imaginary part of the refractive index.

來近似與漫散層相關聯的漫散光之空間分佈

(亦即空間強度剖面)。

Given the approximate value in equation (4), the Fourier transform can be performed according to equation (5)

To approximate the spatial distribution of diffuse light associated with the diffuse layer

(That is, the spatial intensity profile).

。所要角度剖面

可包含(例如及如以上所描述)頂帽形剖面。在給出所要角度剖面

的情況下，諸如方程式(4)及(5)中之近似值的近似值可用以判定一厚度剖面

，該厚度剖面將在給出特定波長

之輻射的情況下產生具有所要角度剖面

之全像圖。應理解，另外或替代地，可使用相似途徑來判定折射率剖面(例如折射率之實數部分與1之偏差

及/或折射率之虛數部分)，該折射率剖面將在給出特定波長

之輻射的情況下產生具有所要角度剖面

之全像圖。此外，為了判定對應厚度剖面可選擇在距全像漫散器一定距離處之所要空間強度剖面，而非選擇所要角度剖面

。然而，在本文中所描述之實例中，為簡單起見描述對厚度剖面

之判定。You can select the desired angle profile

. Desired angle profile

It may include (e.g., and as described above) a top hat-shaped cross-section. When giving the desired angle profile

In the case of, approximate values such as the approximate values in equations (4) and (5) can be used to determine a thickness profile

, The thickness profile will be given at a specific wavelength

Radiate in the case of generating a profile with the desired angle

The hologram. It should be understood that, additionally or alternatively, a similar approach can be used to determine the refractive index profile (for example, the deviation of the real part of the refractive index from 1

And/or the imaginary part of the refractive index), the refractive index profile will be given at a specific wavelength

Radiate in the case of generating a profile with the desired angle

The hologram. In addition, in order to determine the corresponding thickness profile, the desired spatial intensity profile at a certain distance from the holographic diffuser can be selected instead of the desired angle profile.

. However, in the examples described in this article, the thickness profile is described for simplicity

The judgment.

之判定。該演算法接收所選擇材料(例如以上關於表1所描述之散射物質中之一者)之所要角度剖面

、波長

、折射率及/或偏差

。該演算法接著反覆地執行計算，諸如方程式(2)及(3)之經修改版本，以便判定厚度剖面

。該判定可為估計值。可預定反覆數目。替代地，可基於與所估計厚度剖面

相關聯之品質度量來選擇反覆數目。該演算法可使用高度限制，例如以限制厚度剖面使得漫散層之區域不會超過最大厚度及/或不會薄於最小厚度。可基於製造方法，例如製造方法之解析度極限來選擇此類最大及最小厚度。應理解，可使用其他途徑來判定厚度剖面

及/或折射率剖面，例如可使用分析途徑或可使用不同數值方法。In a specific example, the Geschberg-Sachsston algorithm is used to numerically perform the thickness profile

The judgment. The algorithm receives the desired angle profile of the selected material (for example, one of the scattering materials described in Table 1 above)

,wavelength

, Refractive index and/or deviation

. The algorithm then repeatedly performs calculations, such as modified versions of equations (2) and (3), in order to determine the thickness profile

. This decision can be an estimate. The number of repetitions can be predetermined. Alternatively, it can be based on the estimated thickness profile

The associated quality metric is used to select the number of iterations. The algorithm can use height restrictions, for example, to limit the thickness profile so that the area of the diffuse layer does not exceed the maximum thickness and/or is not thinner than the minimum thickness. Such maximum and minimum thicknesses can be selected based on the manufacturing method, for example, the resolution limit of the manufacturing method. It should be understood that other methods can be used to determine the thickness profile

And/or the refractive index profile, for example, an analytical approach can be used or different numerical methods can be used.

之結構1604，可製作以所要角度剖面

散射輻射之全像漫散器。Return to Fig. 16A and Fig. 16B, by configuring corresponding to the determined thickness profile

The structure 1604 can be made to cross section at the desired angle

Holographic diffuser for scattered radiation.

Figures 17, 18, and 19 respectively illustrate example holographic diffusers containing molybdenum, ruthenium, and molybdenum silicide and their performance. The example holographic diffusers of FIGS. 17, 18, and 19 do not include filling layers, but instead include gaps between the structures above them.

而配置之結構1604。針對包含具有為9º之角度分佈之頂帽形剖面的所要角度剖面

，使用上文所描述方法來判定每一全像漫散器之厚度剖面

。使用針對每一各別全像漫散器所包含的材料(亦即鉬、釕及矽化鉬)之折射率資料來判定針對每一全像漫散器之厚度剖面

。Each holographic diffuser contains a profile based on the determined thickness

And the configuration of the structure 1604. For the desired angle profile including a top hat profile with an angle distribution of 9º

, Use the method described above to determine the thickness profile of each holographic diffuser

. Determine the thickness profile of each holographic diffuser using the refractive index data for the materials contained in each individual holographic diffuser (i.e. molybdenum, ruthenium, and molybdenum silicide)

.

172。該厚度剖面

包含具有高度量度0、

或L 之結構的凖隨機配置，其中L 係針對鉬來計算。Figure 17 illustrates the thickness profile determined for the holographic diffuser containing the molybdenum structure

172. The thickness profile

Contains a height measure of 0,

Or quasi-random arrangement of the L, wherein L is calculated based for molybdenum.

FIG. 17 also shows the phase shift profile 170 and the transmission profile 174 for the holographic diffuser including the molybdenum structure. The phase shift profile 170 illustrates how the phase shift experienced by the EUV radiation transmitted through the holographic diffuser at different positions across the diffuser corresponds roughly to the random arrangement of the structure in a random pattern of -π, 0 or π (that is, equivalent to 0, π, and 2π). The transmission profile 174 illustrates how the transmittance of EUV radiation passing through the holographic diffuser is in the range of 0.6 to 1 in a random pattern substantially corresponding to the random arrangement of the structure. The average transmittance of the holographic diffuser is approximately 78%.

。角度剖面176並不確切對應於所要角度剖面

，此係因為在為9º之角度分佈內存在某非均一性。特定言之，在0º下存在亮光點177，指示某零階散射。此外，一些EUV輻射被散射大於9º，此由於在大於9º之角度下出現散射光之「光暈」178而顯而易見。Figure 17 also shows an angular profile 176 of EUV radiation diffused by a holographic diffuser containing a molybdenum structure. The angle profile 176 is substantially constant within an angle distribution of 9°. That is, the angular profile 176 generally corresponds to the desired angular profile

. The angular profile 176 does not exactly correspond to the desired angular profile

, This is because there is some non-uniformity in the angular distribution of 9º. In particular, there is a bright spot 177 at 0º, indicating a certain zero-order scattering. In addition, some EUV radiation is scattered more than 9º, which is obvious due to the "halo" 178 of scattered light at angles greater than 9º.

182。該厚度剖面

包含具有高度量度0、

或L 之結構的凖隨機配置，其中L 係針對釕來計算。Figure 18 illustrates the thickness profile determined for the holographic diffuser containing the ruthenium structure

182. The thickness profile

Contains a height measure of 0,

Or quasi-random arrangement of the L, wherein L is calculated based for ruthenium.

FIG. 18 also shows the phase shift profile 180 and the transmission profile 184 for the holographic diffuser including the ruthenium structure. The phase shift profile 180 illustrates how the phase shift experienced by the EUV radiation transmitted through the holographic diffuser at different positions across the diffuser corresponds roughly to the random arrangement of the structure in a random pattern of -π, 0 or π (that is, equivalent to 0, π, and 2π). The transmission profile 184 illustrates how the transmittance of EUV radiation passing through the holographic diffuser is in the range of 0.4 to 1 in a random pattern substantially corresponding to the random arrangement of the structure. The average transmittance of the holographic diffuser is approximately 66%.

。角度剖面186並不確切對應於所要角度剖面

，此係因為在為9º之角度分佈內存在某非均一性。特定言之，在0º下存在亮光點187，指示某零階散射。此外，一些EUV輻射被散射大於9º，此由於在大於9º之角度下出現散射光之「光暈」188而顯而易見。Figure 18 also shows an angular profile 186 of EUV radiation diffused by a holographic diffuser containing a ruthenium structure. The angle profile 186 is substantially constant within an angle distribution of 9°. That is, the angular profile 186 generally corresponds to the desired angular profile

. The angular profile 186 does not exactly correspond to the desired angular profile

, This is because there is some non-uniformity in the angular distribution of 9º. In particular, there is a bright spot 187 below 0º, indicating a certain zero-order scattering. In addition, some EUV radiation is scattered more than 9º, which is obvious due to the "halo" 188 of scattered light at angles greater than 9º.

192。該厚度剖面

包含具有高度量度0、

或L 之結構的凖隨機配置，其中L 係針對矽化鉬來計算。Figure 19 illustrates the thickness profile determined for the holographic diffuser containing the molybdenum silicide structure

192. The thickness profile

Contains a height measure of 0,

Or quasi-random arrangement of the L, wherein L is calculated for Department of molybdenum silicide.

FIG. 19 also shows the phase shift profile 190 and the transmission profile 194 for the holographic diffuser containing the molybdenum silicide structure. The phase shift profile 190 illustrates how the phase shift experienced by the EUV radiation transmitted through the holographic diffuser at different positions across the diffuser corresponds roughly to the random configuration of the structure in a random pattern of -π, 0 or π (that is, equivalent to 0, π, and 2π). The transmission profile 194 illustrates how the transmittance of EUV radiation passing through the holographic diffuser is in the range of 0.45 to 1 in a random pattern substantially corresponding to the random arrangement of the structure. The average transmittance of the holographic diffuser is approximately 68%.

。角度剖面196並不確切對應於所要角度剖面

，此係因為在為9º之角度分佈內存在某非均一性。特定言之，在0º下存在亮光點197，指示某零階散射。此外，一些EUV輻射被散射大於9º，此由於在大於9º之角度下出現散射光之「光暈」198而顯而易見。Figure 19 also shows an angular profile 196 of EUV radiation diffused by a holographic diffuser containing a molybdenum silicide structure. The angle profile 196 is substantially constant within an angle distribution of 9°. That is, the angular profile 196 generally corresponds to the desired angular profile

. The angular profile 196 does not exactly correspond to the desired angular profile

, This is because there is some non-uniformity in the angular distribution of 9º. In particular, there is a bright spot 197 at 0º, indicating a certain zero-order scattering. In addition, some EUV radiation is scattered more than 9º, which is obvious due to the "halo" 198 of scattered light that appears at angles greater than 9º.

2002。展示在填補層沈積之前的厚度剖面

2002。該厚度剖面

2002包含具有高度量度0、

或L 之結構的凖隨機配置，其中L 係針對釕來計算。在提供填補層之後，所得厚度剖面大體上等於L ，而無任何實質性厚度變化。Figure 20 illustrates the thickness profile of the ruthenium structure as determined for the holographic diffuser including the ruthenium structure and the silicon oxide filling layer

2002. Show the thickness profile before the deposition of the filling layer

2002. The thickness profile

2002 contains a height measure of 0,

Or quasi-random arrangement of the L, wherein L is calculated based for ruthenium. After the filling layer is provided, the resulting thickness profile is substantially equal to L without any substantial thickness change.

FIG. 20 also shows the phase shift profile 2000 and the transmission profile 2004 for the holographic diffuser including the ruthenium structure and the silicon oxide filling layer. The phase shift profile 2000 illustrates how the phase shift experienced by the EUV radiation transmitted through the holographic diffuser at different positions across the diffuser corresponds roughly to the random arrangement of the structure in a random pattern of -π, 0 or π (that is, equivalent to 0, π, and 2π). The transmission profile 2004 illustrates how the transmittance of EUV radiation passing through the holographic diffuser is in the range of 0.3 to 0.5 in a random pattern substantially corresponding to the random arrangement of the structure. The average transmittance of the holographic diffuser is approximately 39%.

。角度剖面2006並不確切對應於所要角度剖面

，此係因為在為9º之角度分佈內存在某非均一性。然而，該非均一性與不具有填補層之先前實例全像漫散器之非均一性相比較低。特定言之，在0º處不存在亮光點，指示減少之零階散射。Figure 20 also shows the angular profile 2006 of EUV radiation diffused by the holographic diffuser containing the molybdenum silicide structure. The angle profile 2006 is substantially constant within an angle distribution of 9°. That is, the angular profile 2006 roughly corresponds to the desired angular profile

. The angular profile 2006 does not exactly correspond to the desired angular profile

, This is because there is some non-uniformity in the angular distribution of 9º. However, this non-uniformity is lower than that of the previous example holographic diffuser without a filling layer. In particular, there is no bright spot at 0º, indicating reduced zero-order scattering.

A holographic diffuser including a filling layer can be beneficially used in applications that require a highly uniform scattering profile. A holographic diffuser without a filling layer is beneficially used in applications that require high EUV transmission.

According to some embodiments of the present invention, a measurement system for determining an aberration map or a relative intensity map for a projection system PS is provided. The measurement system includes one of the diffusers described above. According to some embodiments of the present invention, a lithography device including the measurement system is provided.

In use, the diffuser is positioned so that it can be moved into and out of the optical path of radiation between the illumination system IL and the projection system PS. This type of optical device provides control of the angular distribution of the radiation of the lithography device LA in the field plane downstream of the device. Such field planes include the plane of the support structure MT (that is, the plane of the patterned device MA) and the plane of the substrate table WT (that is, the plane of the substrate W). In order to ensure that the diffuser can move into and out of the optical path of radiation between the illumination system IL and the projection system PS, the diffuser can be installed on the patterned device shielding blade of the lithography device LA, as it is now Discussed.

The lithography apparatus LA is provided with four shrunk mask shielding blades (which can also be referred to as patterned device shielding blades), and the shrunk mask shielding blades define the range of illuminating the field on the patterned device MA. The lighting system IL is operable to illuminate a substantially rectangular area of an object (for example, the patterned device MA) placed on the support structure MT. This substantially rectangular area can be referred to as a slit of the illumination system IL and is defined by four shroud shielding blades. The extent of the substantially rectangular area in the first direction (which may be referred to as the x-direction) is defined by a pair of x-shielding blades. The extent of the substantially rectangular area in the second direction (which may be referred to as the y direction) is bounded by a pair of y shielding blades.

Each of the shielding blades is placed close to the plane of the support structure MT, but slightly outside the plane. The x-shielding blades are arranged in the first plane and the y-shielding blades are arranged in the second plane.

Each of the shielding blades defines an edge of a rectangular field area in the plane of the object receiving radiation. Each blade can move independently between a retracted position and an inserted position, in which it is not placed in the path of the radiation beam, and in the inserted position, it at least partially blocks projection to the object Radiation beam on the top. By moving the shielding blade into the path of the radiation beam, the radiation beam B can be cut off (in the x and/or y direction), thus limiting the range of the field receiving the radiation beam B.

The x direction may correspond to the non-scanning direction of the lithography device LA and the y direction may correspond to the scanning direction of the lithography device LA. That is, the object (and the substrate W in the image plane) can move through the field in the y direction to expose a larger target area of the object (and the substrate W) in a single dynamic scanning exposure. During this dynamic scanning exposure, the y-shielding blade is moved to control the field area so as to ensure that the part of the substrate W outside the target area is not exposed. At the beginning of the scanning exposure, one of the y-shielding blades is placed in the path of the radiation beam B to act as a light-shielding sheet, so that no part of the substrate W receives radiation. At the end of the scanning exposure, another y-shielding blade is placed in the path of the radiation beam B to act as a light-shielding sheet, so that no part of the substrate W receives radiation.

The diffuser can be installed on the patterned device shielding blade of the lithography apparatus LA. In particular, the diffuser may be positioned such that when the shielding blade is positioned in a position within its nominal range of movement during scanning exposure, the diffuser is generally not positioned in the path of the radiation beam.

The diffuser can have any of the following attributes. The diffuser can cause the angular scattering distribution in at least one scattering direction to have a width of 5° to 10° or more. The diffuser can produce uniform or Gaussian angular power distribution (varies according to the scattering angle). The diffuser may have an absorption (for a single pass) of less than 90%, for example less than 50%, for EUV radiation. The diffuser may have a life span of more than 7 years in the lithography device (for example, a lighting effect interval cycle of approximately 0.1% to 1%). The diffuser may be operable to withstand an unattenuated EUV power density of ^{approximately 1 to 10 W/cm 2.} The diffuser may have a size of approximately 1 to 3 mm ² ×1 to 3 mm ² .

In the case of referring to vertical colloidal deposition as the deposition method, additionally or alternatively, the following processes may be used: inkjet printing and spin coating.

According to another embodiment, the transmission diffuser includes a support structure including a porous structure with pores. The support structure can be a nanotube network, such as carbon nanotubes, multi-wall carbon nanotubes, single-wall carbon nanotube bundles, boron nitride or MoS ₂ nanotubes as core fibers. The nanotubes can be randomly aligned to provide structural support for the optically active diffuser material deposited on the tubes.

A scattering layer at least partially covers the support structure, the scattering layer being configured to scatter the received radiation. The scattering layer includes at least one of Mo, Y, Zr, Nb, and Ru. The scattering layer provides an optically active material to diffuse light into a desired light profile. Ideally, the scattering layer has relatively lower EUV light absorption and higher refractive index shrinkage compared with vacuum. The scattering layer has a thickness of at least 10 nm, optionally at least 20 nm, optionally at least 40 nm, and optionally at least 100 nm. This thickness determines the absorbance.

Optionally, the scattering layer supports the top layer, and the top layer contains at least one of MoO ₃ , Y ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , HfO ₂ , ZrO ₂ , Ru, W, metal, and its thickness is at least 0.3 nm , Depending on the situation, at least 1nm. This top layer can provide plasma and high temperature resistance and relief. The diffuser may be a holographic diffuser.

The support structure described in this embodiment can also be used in other embodiments.

Although the use of lithography devices in IC manufacturing may be specifically referred to herein, it should be understood that the lithography devices described herein may have other applications. Other possible applications include manufacturing integrated optical systems, guidance and detection for magnetic domain memory, flat panel displays, liquid crystal displays (LCD), thin film magnetic heads, and so on.

Although the embodiments of the present invention in the context of the content of the lithography device may be specifically referred to herein, the embodiments of the present invention may be used in other devices. Embodiments of the present invention may form part of a mask inspection device, a metrology device, or any device that measures or processes objects such as wafers (or other substrates) or masks (or other patterned devices). These devices can often be referred to as lithography tools. This lithography tool can use vacuum conditions or environmental (non-vacuum) conditions.

Although specific embodiments of the present invention have been described above, it should be understood that the present invention can be practiced in other ways than those described. The above description is intended to be illustrative, not restrictive. Therefore, it will be obvious to those skilled in the art that the invention described can be modified without departing from the scope of the items set forth below.

Clause 1. A diffuser configured to receive and transmit radiation, wherein the diffuser includes: a scattering layer configured to scatter the received radiation, the scattering layer including a first substance and having A plurality of voids are distributed therein, wherein: the first material is a scattering material, or at least one of the voids contains a scattering material and the first material has a lower refractive index than the scattering material.

Clause 2. The diffuser of Clause 1, wherein the first substance is the scattering substance.

Clause 3. The diffuser of Clause 2, wherein the scattering material includes a foam having micropores and the voids are provided by the micropores and the voids contain a vacuum or an inert gas.

Clause 4. The diffuser as in Clause 2, wherein the voids contain one of silicon or silicon nitride.

Clause 5. Such as the diffuser of Clause 1, in which the void contains the scattering material.

Clause 6. The diffuser of Clause 5, wherein the first substance comprises a porous silicon-based structure, and the voids are defined by the micropores of the first substance.

Clause 7. The diffuser according to any one of clauses 1 to 4, wherein the scattering material includes a body that contacts particles, and the gaps are provided between adjacent particles.

Clause 8. The diffuser of Clause 7, wherein each particle in the body of the contacting particle merges with at least one other particle in the body of the contacting particle.

Clause 9. The diffuser of Clause 7 or 8, wherein the particles comprise a binary mixture, the binary mixture comprising a first material and a second material, and one of the second materials has a refractive index different from The first material.

Clause 10. Such as the diffuser of Clause 9, where the first material contains silicon.

Clause 11. Such as the diffuser of Clause 9 or 10, wherein the second material contains molybdenum or ruthenium.

Clause 12. Such as the diffuser of any one of Clauses 7 to 11, wherein the particles have a range of approximately several nanometers in at least one dimension.

Clause 13. Such as the diffuser of any one of Clauses 7 to 12, wherein the particles are different in size in at least one dimension.

Clause 14. For the diffuser of any of the preceding clauses, the scattering material includes a material with a ratio of a first parameter to a second parameter of 1 or less, and the first parameter is a material that will allow the The maximum thickness of one of the layers of the substance that receives 10% transmission of radiation, and the second parameter is the minimum thickness of one of the layers of the substance that will cause a phase shift of Pi.

Clause 15. Such as the diffuser of any of the preceding clauses, wherein voids are distributed in a plurality of layers within the first substance, and each layer is substantially in a plane perpendicular to the propagation direction of the radiation during use.

Clause 16. Such as the diffuser of any of the preceding clauses, in which the voids are distributed in a single layer within the first substance, and the layer is substantially in a direction perpendicular to the propagation direction of the radiation during use. In the plane.

Clause 17. Such as the diffuser of any of the preceding clauses, wherein the scattering material contains a dealloying material.

Clause 18. Such as the diffuser of any of the preceding clauses, wherein the gaps have a range of approximately several nanometers in at least one dimension.

Clause 19. Such as the diffuser of any of the preceding clauses, in which the voids are polydisperse in the first material.

Clause 20. Such as the diffuser of any of the preceding clauses, in which the gaps are randomly or randomly arranged in the first material.

Clause 21. The diffuser of any one of the preceding clauses, wherein the scattering layer has a thickness between 50 nm and 1000 nm.

Clause 22. As the diffuser of any of the preceding clauses, it is configured such that the angular scattering distribution in at least one scattering direction has a width of 5° or greater.

Clause 23. Such as the diffuser of any of the preceding clauses, wherein the scattering material contains one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, or tectonium.

Clause 24. As the diffuser of any of the preceding clauses, it contains a plurality of scattering layers.

Clause 25. Such as the diffuser of Clause 24, in which a first scattering layer is separated from a second scattering layer by an intermediate layer.

Clause 26. Such as the diffuser of Clause 25, in which the intermediate layer contains silicon.

Clause 27. Such as the diffuser of Clause 25 or 26, wherein the intermediate layer includes a layer of separated particles having a lower refractive index than the scattering material.

Clause 28. Such as the diffuser of Clause 27, in which the separated particles are randomly or randomly arranged in the intermediate layer.

Clause 29. Such as the diffuser of Clause 27 or 28, wherein the separated particles include particles of different sizes in at least one dimension.

Clause 30. Such as the diffuser of Clause 1, wherein the first substance and the voids cooperate to generate a holographic image after radiation is received at a surface of the scattering layer.

Clause 31. Such as the diffuser of Clause 30, wherein the holographic image has an angular intensity profile which is in a radially outer part of the holographic image and in a central area of the holographic image At least as strong.

Clause 32. Such as the diffuser of Clause 31, wherein the radially outer part is separated from the center of the holographic image by at least 9° in angle.

Clause 33. Such as the diffuser of any one of clauses 30 to 32, wherein the first substance includes a plurality of structures with varying thicknesses perpendicular to the surface of the scattering layer.

之輻射後形成該全像圖；該全像漫散器具有一有效折射率

；且該複數個結構中之每一者之該厚度為

的整數倍。Clause 34. Such as the diffuser of Clause 33, wherein: the diffuser is operable to have a wavelength upon receiving

After radiation, the holographic image is formed; the holographic diffuser has an effective refractive index

; And the thickness of each of the plurality of structures is

Integer multiples of.

Clause 35. Such as the diffuser of any one of Clauses 30 to 34, in which the voids contain a second substance.

Clause 36. Such as the diffuser of Clause 35, wherein the real part of the refractive index of the second substance is different from the real part of the refractive index of the first substance, and the imaginary part of the second substance is similar to the The imaginary part of the refractive index of the first substance.

Clause 37. Such as the diffuser of Clause 35 or 36, wherein the combined first substance and second substance have a substantially constant combined thickness.

Clause 38. Such as the diffuser of any one of Clauses 30 to 37, wherein the first substance contains one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, or tectonium.

Clause 39. Such as the diffuser of any one of Clauses 35 to 38, wherein the second substance contains silicon.

Clause 40. A holographic diffuser comprising a scattering layer, the scattering layer including a plurality of structures, and the plurality of structures are configured to generate a holographic diffuser after receiving extreme ultraviolet radiation at a surface of the scattering layer. An image diagram, wherein the holographic image has an angular intensity profile that is at least as strong in a radially outer portion of the holographic image as compared to a central area of the holographic image.

Clause 41. The diffuser of any of the preceding clauses further includes a protective layer configured to protect the scattering layer from EUV plasma etching.

Clause 42. Such as the diffuser of any of the preceding clauses, wherein the diffuser further includes a cap layer that at least partially covers the scattering layer to protect the scattering layer during use.

Clause 43. A measurement system used to determine an aberration map or relative intensity map used in a projection system, the measurement system including a diffuser as in any of the preceding clauses.

Clause 44. Such as the measurement system of Clause 43, the measurement system includes: a patterned device; an illumination system configured to use radiation to illuminate the patterned device; and a sensor device; wherein the illumination The system and the patterned device are configured such that the projection system receives at least a portion of the radiation scattered by the patterned device, and the sensor device is configured such that the projection system projects the received radiation onto the And wherein the diffuser is operable to receive the radiation generated by the illumination system and change an angular distribution of the radiation before the radiation illuminates the patterned device.

Clause 45. Such as the measurement system of Clause 44, wherein the diffuser is movable between at least the following positions: a first operating position, wherein the diffuser is at least partially disposed on the In a path of radiation and configured to change an angular distribution of the radiation before the radiation illuminates the patterned device; and a second storage location, wherein the diffuser is placed in the radiation generated by the illumination system Outside the path.

Clause 46. Such as the measurement system of any one of clauses 43 to 45, when including the diffuser of any one of clauses 30 to 40, wherein the holographic image is formed in one of the measurement systems Enter the plane.

Clause 47. A lithography device comprising: a measurement system as in any one of Clauses 43 to 46; and a projection system configured to receive at least a part of the radiation scattered by the patterned device And is configured to project the received radiation onto the sensor device.

Clause 48. Such as the lithography device of Clause 47, wherein the diffuser is installed on a patterned device shielding blade of the lithography device, and one edge of the patterned device shielding blade defines a field of the lithography device Area.

Item 49. A method for forming diffusers such as items 1 to 3 or 14 to 20 for receiving and transmitting radiation, the method includes: forming an alloy layer including a first substance and a third substance Substance, wherein the first substance is a scattering substance; dealloying the alloy layer to remove the third substance from the alloy layer and to form a scattering substance containing the first substance and having a plurality of voids distributed therein Floor.

Clause 50. A method of forming a diffuser for receiving and transmitting radiation, the method comprising: forming a scattering layer by penetrating a porous structure with a scattering material.

Clause 51. As in the method of Clause 50, the scattering layer is formed on a support layer.

Clause 52. A method of forming a diffuser for receiving and transmitting radiation, the method comprising: depositing a plurality of particles on a surface of a support layer to form a mask; A scattering material is deposited on the layer to surround the plurality of particles to form a scattering layer.

Clause 53. Such as the method of Clause 52, which further includes shrinking one or more of the plurality of particles deposited on the support layer so as to expose a portion of the surface of the support layer before depositing the scattering material Larger area.

Clause 54. As in the method of Clause 52 or 53, wherein the particles are deposited on the support layer via vertical colloid deposition.

Clause 55. The method of Clause 52, 53, or 54, wherein the particles form a single layer deposited on the surface of the support layer, and the scattering layer forms a wave scattering surface on the support layer.

Clause 56. Such as the method of Clause 52, 53, or 54, wherein the particles form a plurality of layers deposited on the surface of the support layer, and each of the plurality of layers is substantially vertical in use In a plane in one direction of the received radiation.

Clause 57. Such as the method of any one of Clauses 52 to 56, which further includes removing the particles after depositing the scattering material.

Clause 58. A method of forming a diffuser for receiving and transmitting radiation, the method comprising: depositing a plurality of particles on a surface of a support layer to form a mask; Depositing a second material on the surface of the layer to form a layer of the second material around the plurality of particles; removing at least some of the plurality of particles to form pits in the layer of the second material; Scattering material is deposited into at least some of the pits in the second material to form scattering features in the layer of the second material.

Clause 59. A method of forming a diffuser for receiving and transmitting radiation, the method comprising: depositing a plurality of particles on a surface of a support layer to form a mask; Depositing a second material on the surface of the layer; selectively etching the surface of the support layer to form a plurality of structures on the surface of the support layer; depositing a scattering material on the surface of the support layer, the The scattering material is formed on the plurality of structures to form a scattering layer; wherein the second material is a catalyst and the selective etching includes etching the area of the support layer in contact with the second material, or wherein the second material is A protective material and the selective etching includes etching the area of the support layer that is not in contact with the second material.

Clause 60. A method of forming a diffuser for receiving and transmitting radiation, the method comprising: depositing a plurality of particles on a surface of a support layer so that the particles form a body that contacts the particles.

Clause 61. As in the method of Clause 50, the deposition includes at least one of the following: vertical colloidal deposition, spin coating, and inkjet printing.

Clause 62. Such as the method of Clause 60 or 61, wherein depositing includes fusing the plurality of particles.

Clause 63. As in the method of Clause 62, the plurality of particles are fused by providing heat and/or pressure.

Clause 64. Such as the method of Clause 62 or 63, wherein the plurality of particles are fused by sintering.

Clause 65. Such as the method of any one of clauses 60 to 64, wherein the particles comprise a binary mixture, the binary mixture comprises a first material and a second material, and the second material has a refractive index Different from the first material.

Clause 66. As in the method of any one of Clauses 52 to 65, it further includes forming another scattering layer.

Clause 67. The method as in Clause 66, wherein the other scattering layer is formed according to the method as in any one of Clauses 33 to 40.

Clause 68. The method of clause 66 or 67, wherein forming another scattering layer includes depositing an intermediate layer on top of the scattering layer and forming the other scattering layer on top of the intermediate layer.

Clause 69. The method of any one of clauses 52 to 68, wherein the support layer is formed on a carrier layer, the carrier layer is used to support the support layer when forming the diffuser, and wherein the method further This includes removing the carrier layer once the first and second layers have been formed.

Clause 70. A method of forming a diffuser for receiving and transmitting radiation, the method comprising generating a plurality of structures on a surface of a supporting layer of the diffuser, wherein the structures are arranged in the After receiving the radiation at the surface, a holographic image is produced.

Clause 71. Such as the method of Clause 70, wherein the holographic image has an angular intensity profile, and the angular intensity profile in a radially outer part of the holographic image is at least the same as that of a central area of the holographic image powerful.

Clause 72. Such as the method of any one of clauses 69 to 71, in which lithography is used to generate the plurality of structures.

Clause 73. Such as the method of any one of Clauses 69 to 72, which further includes depositing a second substance into a plurality of voids distributed in the plurality of structures.

Clause 74. Such as the method of any one of Clauses 70 to 73, which further includes generating a thickness profile corresponding to a desired configuration of one of the plurality of surface features, the desired configuration being based on a desired angle profile of the holographic image .

Clause 75. As in the method of Clause 74, generating the surface profile includes using the Geschberg-Sachsston algorithm.

Clause 76. The method of any one of Clauses 52 to 75, further comprising etching the support layer from a surface of the support layer opposite to a surface of the support layer that supports the scattering layer.

Clause 77. Such as the method of any one of Clauses 52 to 76, further comprising providing a cap layer at least partially covering the support layer and/or the scattering layer.

Clause 78. A diffuser configured to receive and transmit radiation, wherein the diffuser includes: a support structure including a porous structure with holes; and a scattering layer that at least partially covers the support Structure, configured to scatter the received radiation.

Item 79. Such as the diffuser of Clause 78, where the supporting structure includes nanotubes.

Clause 80. Such as the diffuser of any one of Clauses 78 to 79, wherein the scattering layer includes at least one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, zirconium, or typhthium.

Clause 81. Such as the diffuser of any one of clauses 78 to 80, wherein the scattering layer has a thickness of at least 10 nm, optionally at least 20 nm, optionally at least 40 nm, and optionally at least 100 nm.

Clause 82. The diffuser of any one of clauses 78 to 81, wherein the scattering layer support comprises at least one of the following top layers: MoO ₃ , Y ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , HfO ₂ , ZrO ₂ , Ru, W, metal, which has a thickness of at least 0.3 nm, and optionally at least 1 nm.

Item 83. Such as the diffuser of any one of items 78 to 82, where the diffuser has at least 10%, at least 20% as appropriate, at least 30% as appropriate, at least 40% as appropriate, and at least 50% as appropriate % Is a porosity fraction.

Clause 84. Such as the diffuser of any of the preceding clauses, wherein the diffuser is a transmission diffuser.

174:透射剖面 176:角度剖面 177:亮光點 178:光暈 180:相移剖面 182:厚度剖面

184:透射剖面 186:角度剖面 187:亮光點 188:光暈 190:相移剖面 192:厚度剖面

194:透射剖面 196:角度剖面 197:亮光點 198:光暈 502:支撐材料層/支撐層 504:載體層 506:散射材料層/散射材料 508:另一層/另一金屬 510:多孔散射層 602:支撐層 604:載體層 606:多孔層 608:散射層 702:支撐層 704:奈米粒子層 712:催化劑之沈積物 714:經修改支撐結構 716:散射材料 802:支撐層 804:奈米粒子層/奈米粒子 806:散射材料層 808:中間層 810:第二散射層 902:支撐層 904:奈米粒子層/奈米粒子 906:第一散射層 908:中間層 910:另一散射層 912:中間支撐結構 1002:支撐層 1004:奈米粒子層/奈米粒子 1006:填充劑層 1008:散射粒子 1010:另一層 1102:支撐層 1104:多分散奈米粒子 1106:散射材料 1108:空隙 1202:載體層 1204:支撐層 1206:罩蓋層 1208:散射層 1210:入射輻射/箭頭/極紫外線(EUV)輻射 1212:箭頭 1402:支撐層 1406:粒子/粒子本體 1406A:第一粒子群體 1406B:第二粒子群體 1408:空隙 1410:經融合粒子本體 1500:高度圖 1602:支撐層 1604:結構 1605:空隙 1606:填補層 2000:相移剖面 2002:厚度剖面

2004:透射剖面 2006:角度剖面 B:極紫外線(EUV)輻射光束 B':經圖案化極紫外線(EUV)輻射光束 CN:控制器 IL:照明系統 LA:微影裝置 MA:圖案化器件 MT:支撐結構 PA:調整構件 PP_IL :照明系統光瞳平面/投影系統光瞳平面 PS:投影系統 SO:輻射源 u:方向 v:方向 W:基板 WT:基板台 x:方向 y:方向 z:方向10: Faceted field mirror device 11: Faceted pupil mirror device 13: Mirror 14: Mirror 17: Reflective marker 17a: First part 17b: Second part 19: Sensor device 21: Transmission diffraction grating 23 : Radiation sensor 25: Radiation 30: Dipole distribution 32: Quadrupole distribution 34: Circle 36: Polar region 50: First middle stack 52: Second middle stack 54: Middle stack 60: First middle stack/line 62: Second middle stack/line 64: another stack/line 66: line 70: middle stack/line 72: second middle stack/line 74: third middle stack/line 76: fourth middle stack/line 78: another Stack 80: First Middle Stack 82: Second Middle Stack 84: Third Stack 86: Another Middle Stack 90: First Middle Stack 92: Second Middle Stack 94: Third Middle Stack 96: Fourth Middle Stack 98: Fifth Stack 100: Middle Stack 102: Second Middle Stack 104: Third Middle Stack 106: Fourth Stack 108: Another Middle Stack 110: Middle Stack 112: Second Middle Stack 114: Third Stack 120: Diffuser 140: first middle stack 142: second middle stack 144: third middle stack 160: first middle stack 162: middle stack 170: phase shift profile 172: thickness profile

174: Transmission profile 176: Angle profile 177: Bright spot 178: Halo 180: Phase shift profile 182: Thickness profile

184: Transmission profile 186: Angle profile 187: Bright spot 188: Halo 190: Phase shift profile 192: Thickness profile

194: Transmission profile 196: Angle profile 197: Bright spot 198: Halo 502: Support material layer/Support layer 504: Carrier layer 506: Scattering material layer/Scattering material 508: Another layer/Another metal 510: Porous scattering layer 602 : Support layer 604: Support layer 606: Porous layer 608: Scattering layer 702: Support layer 704: Nanoparticle layer 712: Catalyst deposit 714: Modified support structure 716: Scattering material 802: Support layer 804: Nanoparticles Layer/Nanoparticle 806: Scattering material layer 808: Intermediate layer 810: Second scattering layer 902: Support layer 904: Nanoparticle layer/Nanoparticle 906: First scattering layer 908: Intermediate layer 910: Another scattering layer 912: Intermediate support structure 1002: Support layer 1004: Nanoparticle layer/Nanoparticle 1006: Filler layer 1008: Scattering particles 1010: Another layer 1102: Support layer 1104: Polydisperse nanoparticle 1106: Scattering material 1108: Void 1202: carrier layer 1204: support layer 1206: cover layer 1208: scattering layer 1210: incident radiation/arrow/extreme ultraviolet (EUV) radiation 1212: arrow 1402: support layer 1406: particle/particle body 1406A: first particle group 1406B : Second particle group 1408: void 1410: fused particle body 1500: height map 1602: support layer 1604: structure 1605: void 1606: filling layer 2000: phase shift profile 2002: thickness profile

2004: Transmission profile 2006: Angle profile B: Extreme ultraviolet (EUV) radiation beam B': Patterned extreme ultraviolet (EUV) radiation beam CN: Controller IL: Illumination system LA: Lithography device MA: Patterned device MT: Support structure PA: adjustment member PP _IL : illumination system pupil plane/projection system pupil plane PS: projection system SO: radiation source u: direction v: direction W: substrate WT: substrate table x: direction y: direction z: direction

The embodiments of the present invention will now be described with reference to the accompanying schematic drawings only as an example, in which:

-Figure 1 depicts a lithography system including a lithography device and a radiation source;

-Figure 2 is a schematic illustration of reflective markers;

-Figure 3A and Figure 3B are schematic illustrations of the sensor device;

-Figure 4A shows the intensity distribution of the dipole illumination mode of the lithography device shown in Figure 1;

-Figure 4B shows the intensity distribution of the quadrupole illumination mode of the lithography device shown in Figure 1;

-Figures 5A to 5C schematically depict intermediate stages in an example program for manufacturing a transmission diffuser;

-Figures 6A to 6C schematically depict the intermediate stages in another example procedure for manufacturing a transmissive diffuser;

-Figures 7A to 7E schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figures 8A to 8D schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figures 9A to 9E schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figures 10A to 10E schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figures 11A to 11C schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figure 12 schematically illustrates the EUV diffuser;

-Figure 13 shows a plot of the extinction coefficient k for EUV radiation versus (1-n) for EUV radiation for some materials;

-Figures 14A to 14C schematically depict the intermediate stages in another example procedure for manufacturing a transmission diffuser;

-Figure 15A illustrates the height map of the example diffuser manufactured according to the procedures of Figure 14A to Figure 14C;

-Figure 15B and Figure 15C depict the scattering angle of the plane wave of radiation incident on the diffuser of Figure 15A;

-Figures 16A and 16B schematically depict an intermediate stage in another example procedure for manufacturing a transmissive diffuser;

-Figure 17 illustrates the properties of the example diffuser manufactured according to the procedures of Figure 16A and Figure 16B;

-Figure 18 illustrates the properties of the example diffuser manufactured according to the procedures of Figure 16A and Figure 16B;

-Figure 19 illustrates the properties of the example diffuser manufactured according to the procedures of Figure 16A and Figure 16B; and

-Figure 20 illustrates the properties of the example diffuser manufactured according to the procedures of Figure 16A and Figure 16B.

54: middle stack

502: support material layer/support layer

504: carrier layer

510: porous scattering layer

x: direction

z: direction

Claims (15)

A diffuser configured to receive and transmit radiation, wherein the diffuser includes: A scattering layer configured to scatter the received radiation, The scattering layer includes a first substance and has a plurality of voids distributed therein, Wherein: the first substance is a scattering substance, or At least one of the voids contains a scattering material and the first material has a lower refractive index than the scattering material. The diffuser of claim 1, wherein the first substance is the scattering substance, wherein the scattering substance includes a foam having micropores and the voids are provided by the micropores and the voids contain a vacuum or An inert gas. Such as the diffuser of claim 2, wherein the voids contain one of silicon or silicon nitride. The diffuser of claim 1, wherein the voids contain the scattering material, wherein the first material includes a porous silicon-based structure, and the voids are defined by the micropores of the first material. The diffuser of any one of claims 1 to 3, wherein the scattering material includes a body that contacts particles, and the gaps are provided between adjacent particles. The diffuser of claim 5, wherein the particles include a binary mixture, the binary mixture includes a first material and a second material, and a refractive index of the second material is different from the first material. Such as the diffuser of claim 6, wherein the first material includes silicon and The second material contains molybdenum or ruthenium. The diffuser of any one of claims 1 to 3, further comprising a supporting structure, wherein the scattering layer at least partially covers the supporting structure, wherein the supporting structure comprises a nanotube. Such as the diffuser of claim 1, wherein the first substance and the voids cooperate to generate a holographic image after radiation is received at a surface of the scattering layer. Such as the diffuser of claim 9, wherein the voids contain a second substance, wherein the real part of the refractive index of the second substance is different from the real part of the refractive index of the first substance, and the second substance The imaginary part is similar to the imaginary part of the refractive index of the first substance. The diffuser of any one of claims 1 to 3, wherein the first substance includes at least one of the following: molybdenum, ruthenium, niobium, rhodium, yttrium, zirconium, or tectonium. Such as the diffuser of claim 10, wherein the second substance contains silicon. A holographic diffuser, comprising a scattering layer comprising a plurality of structures configured to generate a holographic image after receiving extreme ultraviolet radiation at a surface of the scattering layer, wherein The hologram has an angular intensity profile that is at least as strong in a radially outer portion of the hologram compared to a central area of the hologram. A lithography device, which includes: A measurement system for determining an aberration map or a relative intensity map for a projection system, the measurement system including a diffuser as claimed in any one of claims 1 to 13; And a projection system configured to receive at least a portion of the radiation scattered by the patterned device and configured to project the received radiation onto a sensor device. A method of forming a diffuser for receiving and transmitting radiation, the method comprising generating a plurality of structures on a surface of a supporting layer of the diffuser, wherein the structures are configured to receive at the surface After radiation, a holographic image is produced.

Images