Method and device for mask repair

Abstract

Method (200) for processing an object for lithography comprising: Providing (210) a first gas comprising first molecules; Providing (220) a particle beam on a working area of ​​the object for removing a first material in the working area based at least in part on the first gas; wherein the first material comprises ruthenium; wherein the first material corresponds to a layer material of a pattern element (PE) of the object.

Description

1. Technical area

[0001] The present invention relates to methods, a device, and a computer program for processing an object for lithography. In particular, the present invention relates to a method for removing a material, a corresponding device, as well as a method for lithographically processing a wafer, and a computer program for carrying out the method. 2. State of the art

[0002] In the semiconductor industry, increasingly smaller structures are being produced on a wafer in order to ensure higher integration density. Lithographic processes, among others, are used to produce the structures and image them on the wafer. The lithographic processes can include, for example, photolithography, ultraviolet (UV) lithography, DUV lithography (i.e. lithography in the deep ultraviolet spectral range), EUV lithography (i.e. lithography in the extreme ultraviolet spectral range), X-ray lithography, nanoimprint lithography, etc. Masks are usually used as objects for lithography (e.g. photomasks, exposure masks, reticles, stamps in nanoimprint lithography, etc.), which contain a pattern to image the desired structures, for example on a wafer.

[0003] During a lithographic process, a mask can be exposed to high physical and chemical stresses (e.g., during mask exposure, mask cleaning, etc.). Accordingly, high demands are placed on the durability of the mask materials. Over time, certain mask materials have become established for specific mask structures (such as tantalum or chromium for radiation-absorbing and / or phase-shifting mask structures). For example, the mask materials can be designed to provide a thin layer of an absorber in the mask and / or a specific phase-shifting property in a mask structure. However, with the advancement of technical developments in lithography, the high demands placed on the mask materials may become even more stringent.In order to continue to ensure resistant mask materials that, for example, have radiation-absorbing and / or phase-shifting properties, alternative mask materials and the production of masks constructed from them have recently been investigated in the field of lithography.

[0004] For example, US 2021 / 0223681 A1 is directed to the manufacture of a reflective mask that can further reduce the shading effect of a reflective mask and form a fine and highly precise phase-shifting pattern. It comprises a substrate, a reflective multilayer film, and a phase-shifting film. The phase-shifting film has a first and second layer. The first layer comprises a material containing at least one of the following: tantalum and chromium. The second layer comprises a metal-containing material containing ruthenium and at least one of the following: chromium, nickel, cobalt, vanadium, niobium, molybdenum, tungsten, and rhenium. In one configuration, a protective layer is included between a reflective multilayer film and the phase-shifting film, wherein the protective layer contains ruthenium and the first and second layers are layered on the protective layer in this order.

[0005] US 10481484 B2 is directed to the manufacture of a reflective mask comprising a reflective multilayer film, a protective film, and a phase-shifting film formed in this order on a substrate. The protective film is made of a material containing ruthenium as the main component and an anti-diffusion layer containing ruthenium and oxygen. The anti-diffusion layer is formed on a surface of the protective film or as a part of the protective film on a side adjacent to the phase-shifting film to prevent thermal diffusion between the protective film and the material of the phase-shifting film.

[0006] WO 2021 / 100383A1 discloses a reflective mask blank with a phase-shifting film, in which the change in the phase difference and / or the reflectivity of the phase-shifting film is small even when the thickness of the phase-shifting film changes. The reflective mask blank is provided with a multilayer reflective film and a phase-shifting film in the specified order on a main surface of a substrate. The reflective mask blank is characterized in that the phase-shifting film has a lower layer and an uppermost layer, with the lower layer positioned between the uppermost layer and the multilayer reflective film. The lower layer is formed from a material having a total content of ruthenium and chromium of 90 atomic percent or more, or a material having a total content of ruthenium, chromium, and nitrogen of 90 atomic percent or more.The top layer is formed from a material with a total content of ruthenium, chromium and oxygen of 90 atomic percent or more.

[0007] DE 10 2020 208 568 A1 relates to a device and a method for removing at least one individual particle from a substrate, in particular an optical element for extreme ultraviolet (EUV) photolithography. The device comprises an analysis unit configured to determine at least one component of a material composition of the at least one individual particle, and at least one gas injection system configured to provide a gas adapted to the determined component in an environment of the at least one individual particle. Specifically, the adapted gas contributes to removing the at least one individual particle from the substrate.

[0008] Since mask defects cannot generally be ruled out during complex mask manufacturing, mask materials can also develop as (local) mask defects on the mask (e.g., as defects, excess material, malformed material, adhering particles, etc.). However, previous mask repair processes are designed exclusively for technically long-established mask materials. The requirements for mask manufacturing with innovative materials are therefore extremely high.

[0009] The present invention is therefore based on the object of improving this situation. 3. Summary of the invention

[0010] This object is at least partially achieved by the various aspects of the present invention.

[0011] A first aspect of the invention relates to a method for processing an object for lithography. The method of the first aspect comprises providing a first gas comprising first molecules. Furthermore, the method comprises providing a particle beam on a work area of ​​the object for removing a first material in the work area based at least partially on the first gas, wherein the first material comprises ruthenium.

[0012] The invention addresses the problem of removing materials on an object for lithography that are designed to be resistant to removal under chemical and / or physical stress.

[0013] There has recently been discussion about whether structures of an object for lithography should be created from a ruthenium-containing material in order to meet current and future requirements in lithography. The ruthenium-containing material can give the object structures constructed from it increased chemical resistance to the requirements of lithography. A structure of the object can, for example, comprise a three-dimensional geometry in length, width and / or height, a topological step, an elevation, a depression of the object or any topological deviation with respect to a planar plane of the object. For example, the ruthenium-containing material can make up at least one layer of a structure of the object for lithography.

[0014] The ruthenium-containing material can be specifically designed to explicitly prevent the removal of the first material under chemical / physical influences. The ruthenium-containing material can also be configured to prevent the removal / wear of mask structures constructed from it, even under permanent or regular chemical / physical stress. The ruthenium-containing material can, for example, be designed for the extreme conditions of lithographic processes in which the object is to be used for lithography. For example, the object may be exposed to a (damaging) plasma during a lithographic process. For example, it may be necessary for a lithographic process to expose the object to a hydrogen environment (e.g., to prevent defects).During lithographic exposure of the object, a (parasitic) highly reactive hydrogen plasma containing hydrogen radicals can be released, which can act on the object's material. The plasma places a high chemical / physical stress on the object and can cause material removal as well as material damage to the object (e.g., in a similar way to plasma etching). However, the material-removing effect is not desired for the object being lithographically exposed, as this can negatively impact the object's properties and thus the quality of the lithographic process. Therefore, the ruthenium-containing material of corresponding mask structures can be (explicitly) designed to ensure high resistance of the first material to the material-removing effect of a plasma (e.g., in particular, the highly reactive hydrogen plasma).Furthermore, the object may be exposed to numerous other mechanical / chemical influences during lithography, which (e.g., in combination with the plasma exposure) can damage the object. For example, these other damaging influences can include strong temperature fluctuations, exposure radiation, and chemical reactions of the object with purge gases. The ruthenium-containing material can therefore typically be designed to fundamentally counteract all of the damaging material-removing influences during lithography, making mechanical / chemical wear and removal of the ruthenium-containing material more difficult.

[0015] The inventors have recognized that such a ruthenium-containing material can be removed by particle beam induced removal in order to correct any errors caused by excess material. The inventive concept is therefore based on removing materials that are specifically designed to be resistant to removal using a particle beam-based process. In doing so, the inventors made the unexpected discovery that ruthenium-containing material from a lithography object can be removed using a provided gas and a provided particle beam (e.g., via particle beam-induced etching). This was a surprising discovery for the inventors, since it was not foreseeable that the first material, which is resistant to the aggressive conditions of lithography, could be processed or even removed using a particle beam (e.g., without using a plasma).This finding was made even more difficult for the inventors because, according to the prevailing opinion, ruthenium was previously known as a non-removable protective layer in objects for lithography, in order to protect the underlying layers during a (particle beam-based) etching process. Furthermore, it was unexpected for the inventors, given the resistant (ruthenium-containing) first material, that providing a gas comprising first molecules is sufficient for a particle beam-based removal of the first material. According to the invention, it is not necessarily necessary to resort to a complex gas mixture (e.g., with different types of molecules designed for the resistant material). This can ensure that the complexity of the particle beam-based removal is reduced, which, for example, allows for easier process control of the method according to the invention (since, for example,the provision of a single gas places lower demands on the technical implementation than the provision of a gas mixture of, for example, two or more different gases). The invention therefore makes it possible to process objects for lithography which have mask structures made of a (resistant) ruthenium-containing material. The first material can, for example, be designed such that it survives at least 20, at least 50, at least 100 or even at least 1000 cleaning cycles which are carried out during a (UV, e.g. EUV or DUV) mask cleaning, essentially unchanged (so that, for example, in the case of a mask which has the first material as a component of a pattern element of the mask, no printable defects are generated by the cleaning cycles).

[0016] The object for lithography, as described herein, may comprise a lithographic mask. The lithographic mask may be designed such that it can be used in lithography for the production of semiconductor-based chips (e.g., during exposure of a semiconductor-based wafer). The lithographic mask may further comprise any type of lithographic mask that can form an image based on a source of electromagnetic radiation (of any wavelength) and a pattern included on the lithographic mask. The image may comprise a transformation of the pattern. The lithographic mask may, for example, comprise an EUV mask, a DUV mask, a UV mask, an X-ray lithography mask, a binary mask, a phase-shifting mask, etc.Furthermore, the lithographic mask may also comprise a nanoimprint lithography stamp, or a lithography mask that can image a pattern based on a source of particles.

[0017] In one example, the method of the first aspect comprises (only) partially removing the first material in the work area. For example, the method can be carried out in such a way that after the (partial) removal of the first material, the first material is still present in the work area. For example, the method (described herein) can be used to remove a significant portion of the first material in the work area. This can include, for example, removing one or more layers of the first material. In a further example, the removal can create a topology step (e.g., a local depression, an edge, etc.) in the first material. The removal (as described herein) can be understood as a targeted, effective material removal, in contrast to pure surface conditioning or roughening of the first material (which can occur, for example, when using the first material as an etch stop layer).For example, the removal may occur over a depth of at least 10 nm, at least 20 nm, or at least 25 nm.

[0018] The work area mentioned herein can comprise a local area of ​​the object for lithography. However, it is also conceivable that the work area comprises the entire object for lithography. The work area can furthermore have any desired surface dimension, shape and / or (three-dimensional) geometry. For example, the work area can be of a magnitude associated with a specific dimension of the object. For example, the specific dimension can comprise a critical dimension CD of a pattern element (i.e., pattern element) of the object. The pattern element can comprise, for example, part of a mask structure, part of the layers of a mask structure, and / or the mask structure itself. The critical dimension CD can comprise, for example, a defined structure width of the pattern element as well as a defined distance between two (characteristic) pattern elements. The work area can, for example,span an area A that results from the critical dimension CD of the pattern element (e.g., A can correspond to a function of the critical dimension CD, with A = f(CD), e.g., A can be proportional to the critical dimension). Furthermore, the removal of the first material within the work area can take place in such a way that the first material is not necessarily removed over the entire area of ​​the work area, but is (locally) removed in a sub-area of ​​the work area. Alternatively, the removal within the work area can take place in such a way that the first material is removed over the entire area of ​​the work area. Furthermore, the provision of the first gas can take place specifically in a sub-area of ​​the work area (e.g., via a locally positionable gas line with a gas nozzle).Likewise, the particle beam can be provided in such a way that it is directed toward a sub-area of ​​the work area, so that the particles of the particle beam radiate onto the sub-area. Furthermore, the method can include the particle beam being specifically controlled and / or focused locally in the sub-area or within the work area (e.g., to locally control a reaction of the particle beam-induced etching).

[0019] In one example, the method of the first aspect comprises completely removing the first material in the work area. For example, the method can ensure that the first material is no longer present in the work area after removal. The first material can therefore also be removed without residue using the method.

[0020] In one example, the method of the first aspect comprises that the first material is capable of absorbing radiation associated with the object. For example, this radiation associated with the object can comprise electromagnetic radiation with a specific wavelength that can be used in a lithographic process for which the object is designed. For example, the radiation associated with the object can correspond to exposure radiation of the object in the lithographic process. The specific wavelength of the exposure radiation can be understood as the lithographic wavelength of the object. In one example, the object for lithography comprises an EUV mask for an EUV lithography process, wherein the lithographic wavelength (i.e. the wavelength of the exposure radiation) in this case can be 13.5 nm. Furthermore, the radiation can, for example, relate to a DUV lithography process (with, for example, 193 nm or248 nm lithographic wavelength), an i-line lithography process (with e.g. 265 nm lithographic wavelength), as well as any other lithography process (with e.g. a different lithographic wavelength) depending on the object.

[0021] In one example, the first material has an intrinsic material parameter that indicates a significant (e.g., high) absorption of the lithographic wavelength of the object (e.g., an absorption coefficient, an absorption contribution, an imaginary part of the refractive index of the first material). In one example, the extinction coefficient k of the first material may be at least 0.01, 0.015, or at least 0.018 (or, e.g., between 0.01 and 0.02 or 0.015 and 0.18). It is also conceivable that the significant absorption may be defined by a (low) reflectivity of the first material. For example, the reflectivity of the first material (e.g., in the range of the lithographic wavelength) may comprise a maximum of 25 percent, preferably a maximum of 20%, more preferably a maximum of 17%. Furthermore, the first material may comprise a material that is typically present in the object to absorb the lithographic wavelength (e.g.,a material that corresponds to an absorption layer (e.g. a pattern element) of the object).

[0022] In a further example, the first material not only has an intrinsic material parameter per se that suggests significant absorption. In addition, the first material can be geometrically designed such that it can effectively absorb the radiation associated with the object in a local region of the object. For example, the first material can be geometrically constructed in a (local) region of the object such that it causes significant absorption of the radiation of the lithographic wavelength in the (local) region via its absorbing material property and its geometric structure. In this case, the first material in the (local) region can make an imaging contribution to a lithographic process because there is actual (i.e. effective) absorption of the radiation of the lithographic wavelength. The geometry of the first material can be defined, for example, via the layer thickness of the material.over a distance that radiation of lithographic wavelength would pass through the first material in a lithographic process (i.e. an absorption distance). The absorption distance can, for example, take into account the optical refraction of the radiation of lithographic wavelength or an incident beam vector of the exposure radiation. For example, the process can comprise not removing a very thin layer of an inherently (i.e. intrinsically) absorbing material because this thin layer is geometrically unable to significantly absorb the radiation of lithographic wavelength and thus makes no actual (i.e. effective) imaging contribution in a corresponding lithographic process. For example, the significant absorption can be defined via the layer thickness or absorption distance of the first material.can be calculated: The layer thickness of the first material can be at least 20 nm, preferably at least 35 nm, more preferably at least 50 nm, most preferably at least 60 nm. However, the layer thickness of the first material can also be less than 60 nm, e.g., less than 50 nm or less than 35 nm. The significant absorption can further be described such that the intensity of the radiation of lithographic wavelength is attenuated by 70%, preferably 80%, most preferably 90% in a lithographic process (across the first material).

[0023] In one example, the method of the first aspect comprises that the first material corresponds to a layer material of a pattern element of the object (e.g., a mask). The first material can be in the form of a layer material of the pattern element. In one example, the method comprises that the layer material corresponds to a material of an absorption layer of the pattern element. The absorption layer can comprise the layer of the pattern element that is explicitly aligned to absorb radiation of a lithographic wavelength. The (ruthenium-containing) first material can, for example, be designed to enable a small layer thickness of the absorption layer. Furthermore, the (ruthenium-containing) first material can, for example, also be designed to enable a phase-shifting property of a layer of a structure of the object for lithography.

[0024] In one example, the method of the first aspect comprises that the first material further comprises at least one second element. The second element can be understood as part of any substance that is comprised in the first material (ie, the second element can, for example, comprise part of a substance compound, a chemical element, etc.). The first material therefore does not necessarily have to be composed exclusively of ruthenium. The first material can also be (stoichiometrically) in the form Ru a Z b be described with a > 0, b ≥ 0, where Z represents at least the second element (or one or more further chemical elements).

[0025] In another example, the first material may be predominantly composed of ruthenium. For example, the ruthenium content of the first material may be at least 50 atomic percent (at. %), at least 70 atomic percent, at least 80 atomic percent, or at least 90 atomic percent.

[0026] The unit "atomic percent," as described herein, can refer to a mole fraction of the corresponding material, where "atomic percent" indicates, for example, the relative number of particles (e.g., ruthenium atoms) with respect to the total number of particles of the substance (e.g., total number of atoms of the first material). The atomic percent can be detected, for example, using secondary ion mass spectroscopy (SIMS) and / or Auger electron spectroscopy and / or X-ray photoelectron spectroscopy (XPS) (as well as, for example, photoelectron spectroscopy (PES).

[0027] The method of the first aspect described herein is in principle also conceivable with a different ruthenium content of the first material, e.g. < 50 atomic percent or < 10 atomic percent, or also < 1 atomic percent ruthenium content and / or at least 10 atomic percent or at least 25 atomic percent.

[0028] In one example, the method of the first aspect comprises the second element comprising at least one of the following: a metal, a semiconductor. A combination of metal and semiconductor is also possible.

[0029] The metal may, for example, comprise a heavy metal, a light metal, a transition metal, a noble metal, a base metal, and / or a metal alloy. The metal may, for example, comprise at least one of the following: niobium (Nb), zirconium (Zr), Y (yttrium), titanium (Ti), lanthanum (La), molybdenum (Mo), cobalt (Co), and / or rhenium (Re). Furthermore, the metal may comprise at least one of the following: tungsten (W), hafnium (Hf), nickel (Ni), vanadium (V), rhodium (Rh), platinum (Pt), and / or palladium (Pd).

[0030] In one example, the semiconductor comprises a semimetal and / or a compound semiconductor. The semiconductor may comprise direct and / or indirect semiconductors. For example, the semiconductor may comprise at least one of the following: silicon (Si), germanium (Ge), boron (B), arsenic (As), gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs), silicon carbide (SiC), and gallium nitride (GaN).

[0031] It is also conceivable that the second element comprises a non-metal. For example, the non-metal can comprise at least one of the following: oxygen, nitrogen, phosphorus, hydrogen, carbon, or a halogen (e.g., bromine, fluorine, chlorine, etc.).

[0032] In one example, the method of the first aspect comprises the second element comprising at least one of the following: tantalum, chromium, nitrogen, and oxygen. In a preferred example, the first material comprises ruthenium and oxygen. In another preferred example, the first material comprises ruthenium, chromium, and oxygen. In another preferred example, the first material comprises ruthenium and tantalum.

[0033] In one example, the method of the first aspect comprises the ruthenium forming a chemical compound with the second element (or with the at least one second element). The chemical compound can, for example, comprise a binary, ternary and / or quaternary chemical compound. In a preferred example, the chemical compound comprises a ruthenium oxide (e.g. RuO). In a further preferred example, the chemical compound comprises a ruthenium-tantalum compound (e.g. RuTa). It is also conceivable that the chemical compound comprises a ruthenium nitride. Furthermore, at least one of the following binary chemical compounds is conceivable as a chemical compound: RuCr, RuNi, RuCo. In a further example, at least one of the following ternary chemical compounds is conceivable as a chemical compound: RuCrNi, RuCrCo, RuNiCo.In another example, at least one of the following quaternary chemical compounds is conceivable as a chemical compound: RuCrNiCo.

[0034] In one example, the method of the first aspect comprises performing the method such that a second material, which may, for example, be adjacent to the first material (or may be arranged beneath it), is at least partially exposed in the work area by the removal. In this case, a surface of the second material may be exposed by the removal of the first material (as described herein). The second material may, for example, be the material of a layer adjacent to the first material.

[0035] In one example, the method of the first aspect comprises that the first material and the second material differ in at least one element (or substance). For example, in this respect, the second material may comprise substance B, wherein substance B is not a constituent of the first material. In a preferred example, the second material does not comprise ruthenium and / or the at least second element (as described herein). In a further example, the second material may comprise substance A and substance B, wherein substance A is a constituent of the first material (e.g., the at least one second element and / or ruthenium) and wherein substance B is not a constituent of the first material (e.g., ruthenium or the at least one second element). Furthermore, the first and second materials may be materially disjoint (i.e., no substance of the first material corresponds to a substance comprised in the second material).For example, in this respect, the first material may consist of substance C and D in addition to ruthenium, whereby the second material may in this case consist (exclusively) of substance E and F, so that no substance of the first material corresponds to a substance of the second material.

[0036] In one example, the method of the first aspect comprises the second material comprising tantalum and / or a tantalum compound. The tantalum compound may, for example, comprise a tantalum nitride, a tantalum oxide, a tantalum oxynitride, and / or a ruthenium-tantalum compound.

[0037] The second material may further comprise any metal and / or semiconductor. The metal may, for example, comprise a heavy metal, a light metal, a transition metal, a noble metal, a base metal, and / or a metal alloy. For example, the second material may further comprise boron and / or arsenic.

[0038] It is also conceivable for the second material to comprise a non-metal, which does not necessarily have to be part of the tantalum compound. For example, the non-metal can comprise at least one of the following: oxygen, nitrogen, phosphorus, hydrogen, carbon, or a halogen (e.g., bromine, fluorine, chlorine, etc.).

[0039] In one example, the second material comprises tantalum and oxygen. In a preferred example, the second material comprises tantalum, oxygen, and boron. In another preferred example, the second material comprises tantalum, oxygen, and nitrogen.

[0040] It should be noted that the second material does not necessarily have to be limited to tantalum and / or a tantalum compound. Instead of tantalum and / or the tantalum compound, any metal and / or any semiconductor is also conceivable. Furthermore, it is also conceivable for the second material to comprise an oxide and / or a nitride in general.

[0041] In one example, the second material can act as a removal stop (e.g., etch stop) for the removal of the first material. In one example, the method of the first aspect comprises selectively removing the first material such that the second material (or an underlying material) of the object is substantially not removed. For example, the method can be designed such that during the removal according to the invention (e.g., based on particle beam-induced etching), there is a selectivity of removal (e.g., an etch selectivity) of the first material compared to the second material (or an underlying material), e.g., at least 1.5 to 1, at least 5 to 1, or at least 10 to 1. The selectivity can, for example,enable the second material (or an underlying material) to be removed at a lower rate of removal than the first material when the second material (or an underlying material) is exposed to the method (as described herein).

[0042] In one example, the method of the first aspect further comprises removing the second material in the work area. The removal of the second material can be carried out using a particle beam (e.g., via particle beam-induced etching). Providing the first gas and providing the particle beam on the work area of ​​the object can also serve to remove the second material in the work area. In one example, the removal of the first and second materials can be carried out in two different removal steps (e.g., two etching units). In the first removal step, for example, the first material (as described herein) can be removed so that the second material is exposed. The first removal step can be selectively designed such that the second material is substantially not removed. This means that for the first removal step, the second material can be designed as a removal stop (e.g., etching stop).The second removal step can then comprise the actual removal of the second material. For this purpose, for example, an adjustment of process parameters of the particle beam-based method of the first aspect can be carried out. This can, for example, comprise a change in the provision of the first gas (e.g., a change in the gas flow rate, the gas concentration, and / or the gas pressure of the first gas). For example, the second removal step can also be carried out with a different gas composition than the first removal step (e.g., the first molecules in the second removal step can be different from the first molecules in the first removal step). Likewise, a change in parameters of the particle beam can be carried out for the second removal step (e.g., a change in the acceleration of the particles, the particle flow, etc.).The second material can therefore be removed in the second removal step using a different parameter space of the process than the first material in the first removal step.

[0043] However, it is also conceivable that the first material and the second material are removed in a single removal step. In this case, for example, no sequential adjustment of process parameters that are material-specific for the first and then the second material is required. For example, after removing the first material and exposing the second material, the second material is removed via the process without requiring any further material-specific adjustment of process parameters.

[0044] In one example, the method of the first aspect includes completely removing the second material from the work area. For example, the method can enable the second material to no longer be present in the work area (or in the sub-area of ​​the work area) after removal.

[0045] In one example, the method of the first aspect comprises that the method is carried out in such a way that a third material, which may e.g. be adjacent to the second material (or may be arranged underneath it), is at least partially exposed in the work area by the removal of the second material. In one example, the method of the first aspect is designed such that the second material is selectively removed so that the third material of the object is substantially not removed. The third material can therefore serve as a removal stop (e.g. etching stop) for the removal of the second material. This can ensure, for example, that a material lying underneath the third material is not attacked by the particle beam-based method.

[0046] In one example, the method of the first aspect comprises the third material comprising ruthenium. For example, the third material can have the same ruthenium content as the first material (e.g., as described herein). It is also conceivable for the third material to be composed essentially exclusively of ruthenium. The third material can further comprise features and properties described herein for the first material. Furthermore, the first material can also comprise features and properties described herein for the third material.

[0047] In a preferred example, the third material (besides ruthenium) may further comprise niobium (Nb).

[0048] In one example, the method of the first aspect comprises the first and third materials comprising the same elements. For example, the material composition of the first material may correspond to the material composition of the third material. For example, the first material and the third material may consist of the same elements (e.g., the first and third materials may both consist of ruthenium and substance B). The material-specific features / properties of the first and third materials may therefore be identical in this example (but it is also conceivable that the proportions of ruthenium and substance B in the first and third materials are different).

[0049] In one example, the method of the first aspect further comprises removing at least one intermediate material. The intermediate material can comprise any material that is arranged between the first and second materials and / or between the second and third materials. The second material therefore does not necessarily have to (directly) border the first material, but can be coupled to it via the at least one intermediate material. Furthermore, the third material does not necessarily have to (directly) border the second material, but can be coupled to it via the at least one intermediate material. The intermediate material can correspond to a material of at least one intermediate layer. For example, it is conceivable that the at least one intermediate layer is arranged between the first and second materials, or between the second and third materials.The at least one intermediate material may have features and properties that are described herein for materials of the object (e.g., the intermediate material may have features / properties as described herein for the first, second and / or third material).

[0050] In one example, the method of the first aspect comprises that the second and / or the third material corresponds to a layer material of a pattern element and / or a material of a cover layer of a reflective layer stack of the object (or is in the form of a layer material or a cover layer).

[0051] The materials described herein (or the layers constructed therefrom) can be further illustrated using an exemplary object for lithography. The object can, for example, have a characteristic layer structure in which the cover layer is adjacent to the reflective layer stack (e.g., a Bragg mirror) of the object. The characteristic layer structure can further comprise a buffer layer adjacent to the cover layer. A first absorption layer can also be adjacent to the buffer layer.

[0052] In one example, the buffer layer and the first absorption layer are a layer material of a pattern element (e.g., these layers can be part of an absorbent pattern element). The first absorption layer can correspond to the first material (as described herein), while the buffer layer can correspond to the second material (as described herein). In this example, the cover layer can correspond to the third material (as described herein).

[0053] In another example, the characteristic layer structure further comprises a second absorption layer adjacent to the first absorption layer. The second absorption layer can correspond to the first material (as described herein), and the first absorption layer can correspond to the second material (as described herein). In this example, the cover layer can correspond to the third material (as described herein), and the buffer layer can correspond to the at least one intermediate material.

[0054] The method can be designed with a removal selectivity such that the third material (e.g., the material of the cover layer) is substantially not removed. This can enable the method to be terminated in a targeted manner without attacking the reflective layer stack. The cover layer can therefore act as a removal stop (e.g., etch stop), so that damage to the reflective layer stack, which would be accompanied by damage to the optical properties of the object, can be prevented. For example, a removal selectivity (e.g., an etch selectivity) of the second material relative to the underlying material (e.g., the third material and / or the at least one intermediate material), e.g., can be at least 1.5 to 1, at least 5 to 1, or at least 10 to 1.

[0055] In one example, the method of the first aspect further comprises removing at least one surface material of the object. The surface material can, for example, comprise a material of the object which has a surface accessible to both the first gas and the particle beam (e.g., a freestanding surface of the object). The surface material can comprise any desired material and is not limited to the substances and material components of the first (or second and / or third) material mentioned herein. The surface material can, for example, be removed in order to expose the first material arranged underneath for the method according to the invention.

[0056] In one example, the first gas can be understood as a substantial etching gas for removing the first material. The first gas can be designed to have a substantial influence on the etching behavior of the first material. For example, the molecules of the first gas can be selected such that they cause an etching / removing effect on the first material. The first molecules can also be selected such that, in conjunction with a reaction induced by the particle beam, they cause an etching / removing effect on the first material.

[0057] In one example, the method of the first aspect comprises the first molecules comprising a halogen atom. The inventors have recognized that a gas comprising molecules that have a halogen is particularly suitable for removing the (ruthenium-containing) first material. Such a first gas (i.e., etching gas), in conjunction with the provided particle beam, can advantageously remove the resistant first material in a technically desired manner. For example, with such a first gas, removal residues, long etching times, and inhomogeneous material removal can be avoided in the method of the first aspect.

[0058] In one example, the method of the first aspect comprises the first molecules comprising a halogen compound. For example, the halogen compound may comprise a chemical compound having at least one halogen atom, wherein the halogen atom forms a chemical bond with at least one further chemical component (e.g., any further chemical element / atom and / or a further chemical group / compound, etc.). In one example, the halogen compound may comprise exclusively halogens of the same type (e.g., the first molecules may comprise F2, Cl2, Br2, etc.).

[0059] In one example, the method of the first aspect comprises the first molecules comprising a noble gas halide. For example, the noble gas halide may comprise a chemical compound having at least one halogen atom and at least one noble gas atom.

[0060] In one example, the method of the first aspect comprises the noble gas halide comprising at least one of the following: xenon difluoride, XeF2, xenon dichloride, XeCl2, xenon tetrafluoride, XeF4, xenon hexafluoride, XeF6. The inventors have recognized that such noble gas halides (e.g., in particular xenon difluoride) can also advantageously remove the resistant first material in a technically desired manner within the scope of the method of the first aspect.

[0061] In another example, the first molecules comprise a quadrupole moment (or a multipole moment with at least four poles) that is greater than zero. For example, xenon difluoride can have a quadrupole moment greater than zero.

[0062] In one example, the first molecules comprise polar molecules. It has been found that polar molecules with a dipole moment can, in principle, be suitable for the method. In another example, however, the first molecules can also comprise nonpolar molecules. The invention is further based on the concept that nonpolar molecules without a dipole moment can also, in principle, be suitable for the method. In an additional example, the first molecules comprise triatomic molecules. According to the invention, complex compounds with more than three atoms per molecule are not necessarily required for a suitable method of the first aspect.

[0063] In one example, the method of the first aspect further comprises: providing a second gas comprising second molecules, wherein the removal of the first material is further based at least partially on the second gas. The second gas described herein can in this context be understood as an additive gas with respect to the substantial etching gas (i.e., the first gas). As an additive gas, the second gas can further influence the removal or particle beam-induced etching of the first material and, for example, adapt process parameters / results more precisely (e.g., etching rate, anisotropy factor, selectivity, sidewall angle, surface roughness, etc.). In principle, the features described herein for providing the first gas can also apply to providing the second gas, and vice versa.

[0064] In one example, the removal of the second material, the third material, the intermediate material and / or the surface material may further be based on (providing) the second gas.

[0065] In one example, the method of the first aspect comprises a dipole moment associated with the second molecules comprising at least 1.6 D, preferably at least 1.7 D, more preferably at least 1.8 D, most preferably at least 1.82 D.

[0066] The inventors have recognized that this circumstance can be advantageous during the removal of the first material. In particle beam-based removal, a defined (local) gas concentration is usually required over a specific period of time in order to allow the removal reaction to proceed in a defined manner. However, due to chemical and / or physical interactions during the removal of the first material, the defined (local) gas concentration can change to a technically undesirable extent. This is of increased importance, particularly when using a more complex gas mixture comprising at least two gases (e.g., the first and second gas). This entails increased requirements for maintaining the defined (local) gas concentration.For example, a (local) depletion of the second gas (and / or the first gas) within the working area can occur to an increased extent, which can adversely affect the removal of the first material. The inventors have recognized that the use of second molecules with the dipole moments mentioned herein enables optimized conditions in the design of the defined (local) gas concentration when using the first and second gases. Thus, the removal of the first material can also be specifically optimized.

[0067] In one example, the method includes considering the dipole moment of the second molecules as a parameter during the removal of the first material. For example, the dipole moment of the second molecules can define a process parameter (e.g., a gas flow rate of the first and / or second gas) during the removal. For example, the gas flow rate can be selected depending on the dipole moment.

[0068] In one example, the method comprises providing the first gas and the second gas at least partially simultaneously. For example, the first gas and the second gas can be introduced simultaneously into the environment of the work area or into the environment of the object, e.g., during the removal of the first material. This can further comprise providing (at least partially) a first gas flow rate of the first gas and a second gas flow rate of the second gas during the removal, such that the presence of both gases in the environment of the work area / object is ensured. For example, it is possible for the first and second gas flows to be substantially identical. In other examples, however, they can also be different from one another.The simultaneous provision of the first and second gases may further comprise varying the first gas flow rate and the second gas flow rate (when removing the first material).

[0069] In one example, the method comprises providing the first gas and the second gas at least partially at different times. For example, in order to remove the first material, it may be necessary for only one of the two gases to be provided or introduced into the environment of the work area / object in a removal process step. For example, at the beginning of the removal of the first material, it may be necessary for only the first gas (or the second gas) to be introduced into the environment of the work area / object. The second gas (or the first gas) can then be added or provided at a later point in time. Furthermore, it is also conceivable to gradually alternate between (exclusively) providing / introducing the first gas (without the second gas) and (exclusively) providing / introducing the second gas (without the first gas) during the removal process.Furthermore, it is also possible for the end of the process for removing the first material to involve the exclusive provision / introduction of one of the two gases. For example, it is conceivable that the end of the process for producing the material is defined by the exclusive provision / introduction of the second gas.

[0070] In one example, the method of the first aspect comprises the second molecules comprising water, H2O, and / or heavy water, D2O. Water and / or heavy water have proven to be advantageous additive gases for removing the resistant first material. For example, such an additive gas can also be used to optimize the selectivity of removing the first material compared to the second material (or the third material). In a particularly advantageous example, the method comprises XeF2 as the first gas and H2O as the second gas. In a further example, the second molecules of the second gas can also comprise semi-heavy water, HDO.

[0071] In a further example, the second gas (or the second molecules) can comprise an oxygen-containing component, a halide and / or a reducing component. The oxygen-containing component can, for example, have an oxygen-containing molecule. For example, the oxygen-containing component can comprise at least one of the following: oxygen (O2), ozone (O3), hydrogen peroxide (H2O2), nitrous oxide (N2O), nitrogen monoxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3). The halide can, for example, comprise at least one of the following: Cl2, HCl, XeF2, HF, I2, HI, Br2, HBr, NOCl, NOF, ClNO2, FNO2, PCl3, PCl5, PF3, PF5. The reducing component can comprise a molecule that has a hydrogen atom. For example, the reducing component can comprise at least one of the following: H2, NH3, (NH2)2, CH4. In one example, the second gas may comprise water (and / or heavy water) and nitrogen dioxide.

[0072] In one example, the method of the first aspect comprises that the particle beam is at least partially based on an acceleration voltage of less than 3 kV, preferably less than 1 kV, more preferably less than 0.8 kV, most preferably less than 0.6 kV. In these acceleration voltage ranges, the method of the first aspect (as described herein) can advantageously be carried out. For example, in this parameter space, the first material can advantageously be removed with the particle beam. In one example, the particle beam is further based on an acceleration voltage of at least 0.1 kV, preferably at least 0.15 kV, even more preferably at least 0.2 kV, most preferably at least 0.3 kV.

[0073] Furthermore, it is also conceivable for the particle beam to be based on an acceleration voltage of less than 30 kV, preferably less than 20 kV. In one example, an acceleration voltage between 3 kV and 30 kV can be used for imaging purposes within the scope of the method (e.g., for image acquisition before or after removal and / or image acquisition during removal).

[0074] In one example, the particle beam comprises a current intensity between 1 pA to 100 pA, preferably between 5 pA to 80 pA, most preferably between 10 pA to 60 pA.

[0075] In one example, the method of the first aspect comprises that the method is based at least in part on a temperature associated with the first and / or second gas. The temperature can be predetermined. The temperature can be, for example, below 0°C (or below 273.15 K), preferably below -5°C (or below 268.15 K), more preferably below -10°C (or below 263.15 K), most preferably below -15°C (or below 258.15 K). The temperature associated with the first and / or second gas can, for example, correspond to a temperature to which a respective storage container comprising the first (or second) gas is (actively) tempered. The respective storage container can serve as a source or storage from which the first (or second) gas is made available for providing. For example, the providing (as described herein) from a first storage container comprising the first gas, oralso from a second storage container comprising the second gas. The temperature of the respective storage container can be controlled, for example, by means of Peltier elements. In one example, the temperature mentioned here comprises a temperature of the first (or second) gas in the respective storage container before the (actual) provision of the first (or second) gas for the method (as described herein). This can enable the provision of the first (or second) gas to occur from a source which comprises a gas with a defined gas temperature, whereby the method can be implemented, for example, in a defined and reproducible manner. It should be noted that in an example with the provision of the first (or second) gas, the temperature of the first (or second) gas in the working area does not necessarily have to correspond to the temperature of the first (or second) gas in the respective storage container. For example, by providing (e.g.A change in the temperature of the first (or second) gas can occur during the process (comprising a gas transport of the first (or second) gas from the respective storage container via a gas line to the work area). However, by providing the gas from a source with a defined gas temperature (as described herein), the gas temperature of the provided gas (e.g., in the work area) can also be defined and made reproducible.

[0076] In a further example, the temperature (mentioned herein) associated with the first and / or second gas may correspond to a temperature of a (solid and / or liquid) precursor, wherein the first (or second) gas for the process can be formed from the at least one precursor. For example, the precursor may comprise a solid and / or liquid starting material from which the first (or second) gas is generated according to technically common possibilities. The temperature (mentioned herein) may serve to set and / or regulate a vapor pressure of the solid and / or liquid precursor in order to form the first (or second) gas according to technically common possibilities. The temperature may be set / regulated, for example, using Peltier elements. The temperature (mentioned herein) may correspond to a temperature of a reservoir that comprises the precursor. The reservoir (i.e., precursor reservoir) may, for example,be designed exclusively for the precursor. In a further example of the invention, the precursor reservoir can also serve as a storage container for the first (or second) gas. Furthermore, the precursor reservoir can also be coupled to a separate storage container for the first (or second) gas, wherein the first (or second) gas is introduced into the separate storage container (and, for example, stored there) after formation in the precursor reservoir.

[0077] Furthermore, in one example it is also conceivable that the temperature associated with the first and / or second gas comprises a temperature that is present in the environment of the object (e.g. in the work area of ​​the method described herein or in a process chamber in which the object is arranged for the method). For example, this can comprise the temperature of the first (or second) gas in the environment of the object. In a further example it is also conceivable that the object is brought to the temperature (mentioned herein) during the method, e.g. via a corresponding object holder (e.g. a temperature-controlled chuck). In this example in particular it is also conceivable that a predetermined temperature of >0°C is selected.

[0078] In one example, the method further comprises determining an endpoint of the removal based at least in part on detecting electrons emitted from the object. For example, the electrons may be emitted due to an interaction of the provided particle beam with a material of the object or with a material of the work area. For example, these may be electrons that escape from an effective area of ​​the particle beam incident on the material, due to physical reasons, due to the particle beam. In one example, the electrons comprise scattered electrons and / or secondary electrons. The scattered electrons may, for example, comprise backscattered electrons (BSE) and / or forwardscattered electrons (FSE) from the object.The detected electrons can provide information about a material property in the effective range of the particle beam, which can be used to draw conclusions about the material being processed with the particle beam. For example, determining the end point can include using the detected electrons to determine that the particle beam is no longer acting on the first material. This can indicate that the first material has been removed and the end point of the method (i.e. the end of the process) has been reached. Furthermore, determining the end point can include using the detected electrons to determine that the particle beam is processing the second and / or the third material. In this way, for example, the end point of the removal of the first material and / or the end point of the removal of the second material can be determined.In principle, the detected electrons can be used to determine the material currently being processed with the particle beam, regardless of the endpoint determination (e.g., for process monitoring, as a record of the process history, etc.). The particle beam can also be configured to ensure a sufficient signal difference between the detected electrons depending on the material in the effective range (e.g., via an acceleration voltage, current, etc.).

[0079] In one example, the method of the first aspect comprises the particle beam comprising an electron beam. For example, the removal described herein within the scope of the method may comprise electron beam-induced etching (also known, for example, as (F)EBIE - (focused) electron beam induced etching).

[0080] However, it is also conceivable for the particle beam to comprise an ion beam (e.g., consisting of gallium ions, helium ions, etc.). For example, the removal of the first material can be based on ion beam-induced milling / etching (e.g., focused ion beam (FIB) milling). In addition to the use of massive particles, it is also conceivable to use a particle beam of massless particles (e.g., photons).

[0081] Furthermore, the use of several particle beams is also conceivable.

[0082] In one example, the method is carried out such that a sidewall angle (of an edge) of the first (or second) material is 70° to 90°, preferably 74° to 90°, more preferably 78° to 90°, most preferably 80° to 90°. The sidewall angle can, for example, be related to the plane of a layer arranged beneath the first (or second) material, or to the (planar) plane of the object.

[0083] In one example, the method is carried out such that upon exposing the second material (via removing the first material), a surface of the second material has a root mean square roughness, RMS, of less than 3 nm, preferably less than 2 nm, more preferably less than 1 nm, most preferably less than 0.5 nm.

[0084] In one example, the method is carried out such that upon exposing the third material (via removing the first and second materials), a surface of the third material has a root mean square roughness, RMS, of less than 3 nm, preferably less than 2 nm, more preferably less than 1 nm, most preferably less than 0.5 nm.

[0085] In one example, the method of the first aspect comprises performing the method such that a defect of the object is repaired. For example, the method may comprise repairing an opaque defect of the object.

[0086] An opaque defect is a defective area on the lithography object which, according to the design of the object, should not be opaque, i.e., clear (e.g., translucent or designed in such a way that there is no targeted absorption of radiation of a specific wavelength, e.g., the lithographic wavelength). A clear defect, on the other hand, is a defective area on the lithography object which, according to the design of the object, should be opaque (e.g., impermeable or strongly absorbent of radiation of a specific wavelength, e.g., the lithographic wavelength). In particular, opaque can be defined in relation to a lithography process for which the object can be used. For example, the lithography object can comprise an EUV mask for an EUV lithography process, where opaque in this case can refer to the lithography wavelength of 13.5 nanometers.Furthermore, it is conceivable that opaque refers to a DUV lithography process (e.g., at a lithographic wavelength of 193 nanometers or 248 nanometers), an i-line lithography process (e.g., at a lithographic wavelength of 265 nanometers), or any other lithography process depending on the object. Furthermore, an opaque defect can, for example, comprise a defective area that has opaque material of a layer of a lithographic mask (e.g., this can comprise a layer designed as a layer for an opaque pattern element of the object). The process can comprise removing the first material in such a way that the defective area is no longer opaque.

[0087] For example, repairing the defect may first comprise locating the defect (e.g., using a scanning electron microscope, an optical microscope, etc.). The working area used for removing the first material may be defined based on at least one characteristic of the localized defect (e.g., based on a position, shape, size, type of defect, etc.). Removing the defect of the object may further comprise creating a repair shape comprising the defect. In one example, the repair shape may serve as the working area for the methods mentioned herein. The repair shape may, for example, comprise a pixel grid, which may enable localization of a location of the defect. The pixel grid may, for example, be designed to follow the contour of the defect, such that each pixel of the pixel grid substantially corresponds to a location of the defect and thus represents a defect pixel.In another example, the pixel grid has a fixed geometric shape (e.g., a polygon, a rectangle, a circle, etc.) that completely encompasses the defect, although not every pixel necessarily represents a location of the defect. The pixel grid may comprise defect pixels that correspond to a location of the defect and non-defect pixels that correspond to a location that does not cover any part of the defect. In one example, the method comprises directing the particle beam at least at one defect pixel of the pixel grid of the repair shape during the generation of the material. Furthermore, the particle beam may be configured such that it can be directed at each defect pixel during the removal of the first material (or the removal of the second material). This ensures that the removal of the first (or second) material is locally limited to the defect pixels, thus only processing the defect.

[0088] In a further example, the method can be used in processing the object that includes local material generation. The processing, as well as the local material generation, can take place, for example, as part of defect processing of the object (e.g., when repairing a clear defect and / or a defective area, when removing a particle, etc.). Thus, the first material does not necessarily have to be a layer material of the object. The material generation can, for example, include the deposition of a material that corresponds to the properties of the first material (as described herein). For example, the local material generation can result in the first material being generated incorrectly. Accordingly, the method according to the invention can be used to remove the incorrectly generated material as the first material (as described herein).For example, in the context of a complex repair, it may be necessary to specifically create and remove the first material (e.g., this may be necessary if the first material was created as a sacrificial layer).

[0089] In one example, the method of the first aspect comprises the object comprising an EUV mask and / or a DUV mask. For example, the characteristic layer structure described herein can correspond to a layer structure of an EUV mask.

[0090] A second aspect relates to a device for processing an object for lithography, comprising: means for providing a first gas; means for providing a particle beam on a work area of ​​the object, wherein the device is configured to carry out a method of the first aspect. Furthermore, the device can comprise means for executing a computer program (e.g., a computer system, a computing unit, etc.). The device can essentially correspond to a scanning electron microscope, which can provide an electron beam as a particle beam on the object. The scanning electron microscope can be configured to provide the gases described herein. The first gas (and / or the second gas) can, for example, be stored in corresponding reservoirs and guided into the work area of ​​the object via a gas supply system (e.g., a gas line with a gas nozzle).The device may further comprise a control system which is set up to carry out the method automatically.

[0091] A third aspect relates to an object for lithography, wherein the object has been processed using a method of the first aspect. In this case, it can be demonstrated, for example, by an optical examination of the object whether the object has been processed using a method of the first aspect. For example, an initial optical examination can have been or is carried out for the object for lithography (e.g. as part of a defect qualification of the object, e.g. following production of the object and / or when the object is introduced into a semiconductor plant). The optical examination can, for example, be based on an optical or particle-optical microscope (e.g. on a mask metrology device, a mask microscope) and, for example, comprise image recording. When the object is processed according to an example of the first aspect following the initial examination, the first (orsecond) material must have been removed as described herein. The removal of the first (or second) material can be verified by a repeated optical examination (e.g., as part of a repair inspection or a renewed defect qualification). The verification can be performed, for example, by comparing the initial optical examination with the repeated optical examination (e.g., by comparing the corresponding images). Furthermore, the verification of the method can also be based on a material analysis of the object (e.g., Auger spectroscopy, X-ray spectroscopy, etc.), which is performed, for example, in addition to the initial or repeated optical examination.

[0092] A fourth aspect relates to a method for processing a semiconductor-based wafer. The method of the fourth aspect further comprises lithographically transferring a pattern associated with an object for lithography onto the wafer, wherein the object was processed using a method of the first aspect. The lithographic transfer may comprise a lithography method for which the object is designed (e.g., EUV lithography, DUV lithography, i-line lithography, etc.). For example, the method of the fourth aspect may comprise providing a beam source of electromagnetic radiation (e.g., EUV radiation, DUV radiation, i-line radiation, etc.). Furthermore, providing a developable resist layer on the wafer may be included. The lithographic transfer may further be based at least partially on the beam source and the provision of the developable resist layer. In this case, for example,The pattern is imaged onto the lacquer layer (in a transformed form) using the radiation from the beam source.

[0093] The methods described herein can, for example, be stored in writing. This can be implemented, for example, via a digital file, analogue (e.g. in paper form), in a user manual, in a recipe (which is, for example, stored in a device and / or a computer in a semiconductor plant). Furthermore, it is conceivable that a written protocol is created when one of the methods described here is carried out. The protocol can, for example, make it possible for the execution of the method, as well as its details (e.g. the recipe), to be documented at a later date (e.g. in the context of a defect assessment, a material review board, an audit, etc.). The protocol can, for example, comprise a protocol file (i.e. log file), which can, for example, be stored in a device and / or a computer.

[0094] A fifth aspect relates to a computer program comprising instructions which, when executed by a computer system, cause the computer system to perform a method according to the first aspect and / or a method according to the fourth aspect.

[0095] A further aspect relates to the mentioned device having a memory which comprises the computer program. The device can further comprise means for executing the computer program. Alternatively, it is also possible for the computer program to be stored elsewhere (e.g. in a cloud) and for the device to merely comprise means for receiving instructions which result from the execution of the program elsewhere. In either case, this can, for example, enable the method to run automatically or autonomously within the device. In this way, intervention, e.g. by an operator, can be minimised, so that both the costs and the complexity of processing masks can be minimised. 4. Short description of the characters

[0096] In the following detailed description, technical background information and embodiments of the invention are described with reference to the figures, which show the following: Fig. 1 schematically illustrates in a top view an exemplary repair situation of an object for lithography. Fig. Figure 2 shows a schematic diagram of an exemplary method of the invention. Fig. 3a-c schematically illustrates in a cross-section exemplary processes in a method of the invention. Fig. 4 shows a schematic view of an exemplary device of the invention. 5. Detailed description of possible embodiments

[0097] Fig. 1 schematically illustrates, in a top view, an exemplary repair situation of an object for lithography. The object for lithography may comprise a lithographic mask suitable for any lithography process (e.g., EUV lithography, DUV lithography, i-line lithography, nanoimprint lithography, etc.). In one example, the lithographic mask may comprise an EUV mask, a DUV mask, an i-line lithography mask, and / or a nanoimprint stamp. Furthermore, the object for lithography may comprise a binary mask (e.g., a chromium mask, an OMOG mask), a phase mask (e.g., a chromium-free phase mask, an alternating phase mask (e.g., a rim phase mask)), a halftone phase mask, a tritone phase mask, and / or a reticle (e.g., with a pellicle). The lithographic mask may, for example, be used in a lithography process for producing semiconductor chips.

[0098] The object for lithography may contain (unwanted) defects. For example, a defect may have been caused during the object's manufacture. Furthermore, a defect may also be caused by (lithographic) processing of the object, a process deviation during (lithographic) processing, transport of the object, etc. Due to the usually costly and complex production of an object for lithography, defects are usually repaired.

[0099] In the embodiments described herein, an EUV mask is often used as an example of an object for lithography for illustrative purposes. However, any object for lithography is conceivable instead of the EUV mask (e.g., as described herein).

[0100] Fig. 1 can schematically depict, in a top view, two local states D, R of a section 1000 of an EUV mask during the repair of a defect in the mask. The section 1000 shows a part of a pattern element PE of the EUV mask. The pattern element PE can also be understood as a pattern element (or as a pattern structure) of the EUV mask. The pattern element PE can be a part of a designed pattern, which can be transferred, for example, to a wafer using a lithographic process. The local state D shows an opaque defect 1010 that borders the pattern element PE. The opaque defect 1010 can, for example, be characterized by excess (opaque) material, which should not be present at the defect location according to the mask design. The excess (opaque) material can, for example,an opaque material of the pattern element PE, as well as any other material of a layer of the pattern element PE (as described herein). With respect to . Fig. 1 (state D), a defect-free pattern element PE in the section 1000 would have to have a rectangular shape, whereby it is clear that this desired state is not present due to the opaque defect 1010. By means of a repair process RV, the excess (opaque) material in the area of ​​the opaque defect 1010 is removed, so that a repaired state R of the pattern element PE can be created. Thus, in state R it is shown that in the original defect area 1020 (i.e. at the original location of the opaque defect) no opaque effect occurs and no excess (opaque) material is present anymore. By removing the defect 1010, the desired state of the rectangular shape of the pattern element PE is therefore restored after a repair process.

[0101] During use in lithography devices or lithography processes, a lithographic mask can be exposed to extreme physical and chemical environmental conditions. This applies in particular to the exposure of EUV masks (as well as DUV masks, or other masks as described herein) during a corresponding lithography process, whereby the opaque material of a pattern element PE can be particularly exposed to these influences. For example, during EUV exposure, a hydrogen plasma with hydrogen radicals can be released, which can, among other things, attack the opaque material of the pattern element PE and cause a material-changing and / or removal effect. Further damaging influences can occur during the EUV lithography process and mask cleaning processes. Damage to the mask material includes, for example,a chemical and physical change of the material through (EUV) radiation, temperature, as well as a reaction with hydrogen or other reactive hydrogen species (e.g., radicals, ions, plasma, etc.). The change of the material can also be caused by a reaction with purge gases (e.g., N2, extreme clean dry air - XCDA). ® , noble gases, etc.) in conjunction with the exposure radiation (e.g., EUV radiation, DUV radiation). Material damage can also be caused or exacerbated by downstream processes (e.g., mask cleaning). These downstream processes can, for example, further attack the opaque material of the pattern element PE, which has already been damaged by chemical / physical reactions during the exposure process, and thus intensify the damage.

[0102] Therefore, a chemically resistant material can be used as the opaque material of a PE pattern element. In particular, ruthenium-containing materials (as described herein) can be used as the resistant material of the PE pattern element in an EUV mask due to their very high chemical resistance. The ruthenium-containing materials can, for example, be in the form Ru. a Z b(a, b ≥ 0, Z: one or more further elements with the stoichiometric coefficient b applicable to the respective element). Z can comprise a metal, non-metal, semimetal, alkali metal (e.g. Li, Na, K, Rb, Cs). Furthermore, Z can comprise an alkaline earth metal (e.g. Be, Mg, Ca, Sr, Ba), an element of the 3rd main group (e.g. B, Al, Ga, In, Tl), an element of the 4th main group (e.g. C, Si, Ge, Sn, Pb), an element of the 5th main group (e.g. N, P, As, Sb, Bi). Furthermore, Z can be a chalcogenide (e.g. O, S, Se, Te), a halogen (e.g. F, Cl, Br, I), a noble gas (atom) (e.g. He, Ne, Ar, Kr, Hg).

[0103] However, this type of resistant (opaque) material of a pattern element PE or an EUV mask can significantly complicate the repair process RV of an opaque defect 1010, since the resistant (opaque) material is to be specifically removed during the repair process.

[0104] Fig. 2 shows a schematic diagram of an exemplary method 200 of the invention. The method 200 can be used to remove material from an EUV mask. In particular, the method 200 can be used to remove material from an opaque defect 1010 as part of a repair process.

[0105] The method 200 may include providing 210 a first gas comprising first molecules. The first gas may, for example, comprise XeF2 as the first molecules. Furthermore, other gases are also conceivable as the first gas, as described herein.

[0106] For method 200, further molecules are also suitable as first molecules of the first gas. For example, both polar and nonpolar triatomic molecules are conceivable. The first molecules can further comprise molecules that can be cleaved into chlorine or fluorine radicals under suitable reaction conditions and / or can further be cleaved, for example, into another nonpolar species.

[0107] Furthermore, the method 200 can comprise providing 220 a particle beam on a work area of ​​the object for removing a first material in the work area, based at least partially on the first gas. The first material can comprise ruthenium. The method 200 can further comprise the characteristic 230 that the first material comprises at least 50 atomic percent ruthenium, preferably at least 70 atomic percent ruthenium, particularly preferably at least 90 atomic percent ruthenium. The method 200 can further comprise an electron beam as the particle beam, so that electron beam-induced etching of the first material according to the method 200 can be enabled.

[0108] The first material may in particular correspond to the resistant (opaque) material of the EUV mask (as described herein), which is to be removed as part of the repair of an opaque defect.

[0109] The method 200 may further comprise providing a second gas as an additive gas that supports the etching process (e.g., with regard to etch selectivity, etch rate, anisotropy factor, etc.). In particular, XeF2 may be used as the first gas in the electron beam-induced etching, and H2O (i.e., water (vapor)) may be used as the additive gas within the scope of the method 200. Furthermore, the second molecules may have a dipole moment between 1.6 D and 2.1 D, preferably between 1.7 D and 2 D, more preferably between 1.8 D and 1.95 D, most preferably between 1.82 D and 1.9 D. It is further conceivable that H2O is combined with nitrogen dioxide (or another oxidative gas) as an additive gas.

[0110] Fig. 3a-c schematically illustrate, in a cross-section, exemplary processes of the method 200 that can take place within the scope of a repair of a defect in an object for lithography.

[0111] Fig. Figure 3a schematically presents an exemplary characteristic layer structure of a reflective lithographic mask for the EUV wavelength range (i.e., an EUV mask). The exemplary EUV mask can, for example, be designed for an exposure wavelength in the range of 13.5 nm. The EUV mask can comprise a substrate S made of a material with a low thermal expansion coefficient, such as quartz. Other dielectrics, glass materials, or semiconducting materials can also be used as substrates for EUV masks.

[0112] A deposited multilayer film or a reflective layer stack ML can be deposited on the substrate S, comprising, for example, 20 to 80 pairs of alternating molybdenum (Mo) and silicon (Si) layers, also referred to as MoSi layers. The individual layers of the multilayer film ML can differ in their refractive index, creating a Bragg mirror that can reflect incident radiation (e.g., EUV radiation).

[0113] To protect the reflective layer stack ML, a capping layer D (also called a "capping layer") can be applied, for example, to the uppermost layer of the reflective layer stack ML. The capping layer D can protect the reflective layer stack ML from damage caused by chemical processes during production and / or during use of the EUV mask (e.g., during a lithographic process). The capping layer D can comprise (elemental) ruthenium, as well as elements or compounds of elements that increase the reflectivity at a wavelength of 13.5 nm by no more than 3%. Furthermore, the capping layer D can comprise Rh, Si, Mo, Ti, TiO, TiO2, ruthenium compounds, ruthenium alloys, ruthenium oxide, niobium oxide, RuW, RuMo, RuNb, Cr, Ta, nitrides, as well as compounds and combinations of the aforementioned materials. The cover layer may further comprise one of the following materials: RuRh, RuZr, RuZrN, RuNbN, RuRhN, RuV, RuVN.

[0114] The cover layer D can have a plurality of layers, which can, for example, comprise the layers of the pattern element (i.e., pattern element layers). The pattern element layers can comprise a buffer layer P, an absorption layer A, and / or a surface layer O. The properties of the pattern element layers (e.g., an intrinsic material property of a pattern element layer, a layer thickness of a pattern element layer, etc.) and the geometry of the pattern element PE formed therefrom can be designed to cause an opaque effect with respect to the exposure wavelength of the EUV mask. For example, the pattern element PE can be designed such that it is opaque (i.e., opaque or strongly light-absorbing) to light radiation with a wavelength of 13.5 nm.The pattern element layers can correspond to the layers of the opaque defect 1010, although the opaque defect 1010 does not necessarily have to include all pattern element layers. For example, the opaque defect 1010 can include only the buffer layer P and the absorption layer A.

[0115] The buffer layer P can be located on the cover layer D. Furthermore, the absorption layer A can be located on the buffer layer P. The absorption layer A can be effectively designed to absorb the radiation of lithographic wavelengths (as described herein). Accordingly, the absorption layer A can make the main contribution to an opaque effect of the pattern element (or the opaque defect 1010). The optical properties of the absorption layer A can be described, for example, by a complex refractive index, which can include a phase-shifting contribution (i.e., n) and an absorption contribution (i.e., k). For example, n and k can be regarded as intrinsic material properties of the absorption layer. Only certain chemical elements and / or compounds of chemical elements have advantageous phase-shifting and / or absorptive properties for the corresponding lithography process (e.g., an EUV lithography process). Fig. 3a shows, by way of example, the layer thickness d of the absorption layer A. The layer thickness d of the absorption layer A (as well as a layer thickness of another layer of the mask) is determined, for example, along a normal vector in relation to the planar plane of the mask. In principle, it is also conceivable for the absorption layer A to comprise a plurality of absorption layers which, for example, comprise different materials. Furthermore, the surface layer O can be located on the absorption layer A. The surface layer O can comprise an anti-reflection layer, oxidation layer and / or passivation layer. In addition to the absorption layer A, the buffer layer P and / or the surface layer O can also contribute to the absorption or to the opaque effect of the pattern element PE or the opaque defect 1010.

[0116] In principle, each of the pattern element layers described herein can comprise the aforementioned resistant first material (ie, ruthenium-containing material). Typically, for example, the absorption layer A comprises ruthenium. The first material of the method 200 can therefore comprise a material of the absorption layer A. Furthermore, however, the buffer layer P or the surface layer O can also comprise ruthenium, for example, and thus constitute the first material of the method 200.

[0117] Fig. 3b shows a result of an exemplary method 200 for removing a portion of the absorption layer A. The absorption layer A is configured as the first material of the method 200. Initially, a portion of the surface layer O can be removed. For example, this can be done analogously to the method 200 via electron beam-induced etching in a separate step. The removal of the surface layer does not necessarily have to be done with the first and / or second gas (as described herein). It is also conceivable that the electron beam-induced etching is configured exclusively for removing the surface layer (e.g., with an etching gas that is adapted to the material of the surface layer). After the removal of the surface layer O, a portion of the absorption layer A can then be removed as the first material within the scope of the method 200 (e.g., to repair an opaque defect). Fig. 3b illustrates a selective electron beam-induced etching of the absorption layer A relative to the buffer layer P. Accordingly, the method 200 can be set such that the etching rate of the absorption layer A is increased relative to the etching rate of the buffer layer P. For example, the etch selectivity can be set via the properties of the second gas in the method 200 (e.g., via a suitable choice of the second gas (e.g., water) or the gas flow rate of the second gas). Furthermore, the etch selectivity can also be set via the properties of the first gas (e.g., via the choice of the first gas (e.g., XeF2) or the gas flow rate of the first gas). In this example, the buffer layer P therefore acts as an etch stop via the selected etch selectivity.

[0118] Fig. 3c shows a further result of an exemplary method 200 for removing a portion of the absorption layer A. Initially (as described herein), a portion of the surface layer O can be removed. After removing the surface layer O, a portion of the absorption layer A can then be removed as the first material within the scope of the method 200. In this case, a portion of the buffer layer P can also be etched as an intermediate material. Accordingly, the method 200 can be set such that the etch rate of the absorption layer A, as well as the etch rate of the buffer layer P, is increased compared to the etch rate of the cover layer D. The etch rate of the absorption layer A can be of the same order of magnitude as the etch rate of the buffer layer P. The etch selectivity can be set as described herein. As in Fig. As shown in Figure 3c, selective electron beam-induced etching of the absorption layer A and the buffer layer P can be performed relative to the cover layer D. In this example, the cover layer D therefore acts as an etch stop via the selected etch selectivity.

[0119] In one example, the surface layer O is not removed separately, but via the same process that is used for the local removal of the absorption layer A (or the absorption layer A and the buffer layer P) in a method 200.

[0120] Furthermore, it should be mentioned that the parameter space (e.g., gas parameters of the first / second gas, particle beam parameters) of method 200 can depend, on the one hand, on the layer currently being processed (with the particle beam). This can, for example, correspond to a step-by-step removal of layers (or materials), with the parameter space of method 200 being adapted for each layer (or materials). However, it is also possible for the parameter space of method 200 not to depend on the layer currently being processed (with the particle beam). This approach can also be used, for example, to remove several layers (or materials) one after the other.

[0121] The method 200 can also be applied for a different specific layer structure of the object for lithography than in Fig. 3a-c. The specific layer structure of the object (e.g., the EUV mask) can still have a cover layer that adjoins a reflective layer stack of the object. A first layer can adjoin this cover layer. A second layer can adjoin this first layer. Starting from the substrate, the specific layer structure can therefore comprise the following layers in this order: substrate, reflective layer stack, cover layer, first layer, second layer. The first and second layers can constitute a layer of a pattern element. In one example, the first and second layers are specifically designed as absorption layers for a pattern element (e.g., with respect to the lithographic process). The absorption of the lithographic wavelength (as described herein) can effectively be defined across the two layers (i.e., the first and second layers). E.g.the first and second layers can have different thicknesses in order to design the optical properties of the object for lithography. In a first example of the specific layer structure, the cover layer can comprise ruthenium and niobium. The first layer can comprise tantalum, boron and oxygen. The second layer can comprise ruthenium, chromium and nitrogen. In a second example, the specific layer structure is defined in that the cover layer essentially comprises ruthenium, wherein the first layer comprises tantalum, oxygen and nitrogen (e.g. tantalum oxynitride, TaON). ​​In this second example, the second layer of the specific layer structure can comprise ruthenium and oxygen (this can be ruthenium oxide, which can be referred to as RuOx, for example).

[0122] With regard to the specific layer structure described herein, the first material (within the meaning of method 200 or the method of the first aspect) may correspond to a material of the second layer. The second material (within the meaning of method 200 or the method of the first aspect) may correspond to a material of the first layer. The third material (within the meaning of method 200 or the method of the first aspect) may correspond to a material of the cover layer. In one example, the first layer of the specific layer structure (e.g., also as an absorption layer) also comprises ruthenium. In this case, the material of the first layer may comprise features / properties as described herein for the first material.

[0123] For the first example of the specific layer structure, the inventors identified particularly advantageous parameter spaces for the targeted removal of the first material (in this case Ru, Cr, N) and the second material (in this case Ta, B, O), whereby the third material (in this case the cover layer made of Ru, Nb) was used to determine the endpoint of the process. To achieve favorable results, XeF2 was used as the first gas and H2O as the additive gas in the test series. A first test series comprised existing process properties: a XeF2 precursor reservoir maintained at -15°C, which was used to form the XeF2 gas, an H2O precursor reservoir maintained at -36°C, which was used to form the H2O gas, an electron beam residence time of 0.1 µs, and a frame refresh time of 1000 µs.Furthermore, gas chopping was used to provide the second (additive) gas, with a gas chopping ratio of 1:15. In other examples, both precursor reservoirs can be kept at other temperatures, e.g., below 0°C, e.g., the XeF2 precursor reservoir at -30°C to 0°C or -25°C to -5°C, e.g., the H2O precursor reservoir at -50°C to -20°C or -45°C to -25°C. In these examples, the frame refresh time can range from 0.1 to 10 ms, preferably 0.2 to 5 ms, particularly preferably 0.5 to 2 ms, wherein the gas chopping ratio can be selected in the range from 1:5 to 1:25 or 1:10 to 1:20. Gas chopping involves the continuous provision of the additive gas over a specific period of time t. X a sequence, where after the specified period t X the provision of the second gas until the sequence is completed for the time t Yis interrupted. The duration of a sequence (ie t S ) can therefore be calculated over the entire duration t S = t X + t Y After the sequence has been completed, a new sequence is started with the described time sequences for providing the additive gas. This process can be repeated as often as required (e.g., until the end of the procedure). Thus, the provision of the additive gas can take place in a "pulsed" form (instead of a continuous provision). The gas chopping ratio (e.g., 1:15) specifies the ratio of the provision time t X for the non-provision period t Y of the gas over a sequence. The gas chopping ratio can determine the delivery time t X and the non-provision period t Y in seconds (e.g. a gas chopping ratio of 1:15 can mean that t X one second and t Y15 seconds, where the corresponding sequence t S 16 seconds).

[0124] A second series of tests was conducted with a XeF2 precursor reservoir maintained at -20°C and a H2O precursor reservoir maintained at -34°C, an electron beam residence time of 0.05 µs, and a frame refresh time of 1000 µs. A gas chopping ratio of 1:15 was used. In other examples, both precursor reservoirs can be maintained at different temperatures, e.g., below 0°C, for example, the XeF2 precursor reservoir at -40°C to 0°C or -30°C to -15°C, or the H2O precursor reservoir at -50°C to -20°C or -45°C to -25°C. In these examples, the frame refresh time can range from 0.1 to 10 ms, preferably 0.2 to 5 ms, particularly preferably 0.5 to 2 ms, wherein the gas chopping ratio can be selected in the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20.A third series of tests was conducted with a XeF2 precursor reservoir maintained at -10°C and a H2O precursor reservoir maintained at -36°C, an electron beam residence time of 0.1 µs, and a frame refresh time of 1000 µs. A gas chopping ratio of 1:1 was used. In other examples, both precursor reservoirs can be maintained at other temperatures, e.g., below 0°C. For example, the XeF2 precursor reservoir can be maintained at -20°C to 0°C or -15°C to -5°C, and the H2O precursor reservoir can be maintained at -50°C to -20°C or -40°C to -30°C. In these examples, the frame refresh time can range from 0.1 to 10 ms, preferably 0.2 to 5 ms, particularly preferably 0.5 to 2 ms, wherein the gas chopping ratio can be selected in the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20.

[0125] The inventors have also identified advantageous parameter spaces for the targeted removal of the first material (in this case RuOx, i.e. ruthenium oxide) and the second material (in this case TaON) for the second example of the specific layer structure, whereby the third material (in this case the cover layer made of Ru) was used to determine the endpoint of the process. To achieve advantageous results, XeF2 was used as the first gas and H2O as the additive gas for each test series of the second example. However, the influence of an additional oxidative gas (in this case nitrogen dioxide) in the additive gas on the removal was also investigated. The test series of the second example were numbered from test series four to test series seven, starting from the test series of the first example of the specific layer structure.A fourth test series was conducted with a XeF2 precursor reservoir maintained at -15°C and an H2O precursor reservoir maintained at -36°C, an electron beam dwell time of 0.1 µs, and a frame refresh time of 1000 µs. A gas chopping ratio of 1:30 was used. In other examples, both precursor reservoirs can be maintained at different temperatures, for example, below 0°C, e.g., the XeF2 precursor reservoir at -30°C to 0°C or -20°C to -5°C, or the H2O gas at -50°C to -20°C or -40°C to -30°C. A fifth test series corresponded to the parameters of the fourth test series mentioned herein, with additional nitrogen dioxide (with a gas flow rate of 1.2 sccm) being provided.A sixth series of tests was conducted with a XeF2 precursor reservoir maintained at -20°C and a H2O precursor reservoir maintained at -36°C, an electron beam residence time of 0.1 µs, and a frame refresh time of 1000 µs. A gas chopping ratio of 1:30 was used. In other examples, both precursor reservoirs can be maintained at different temperatures, e.g., below 0°C, e.g., the XeF2 precursor reservoir at -40°C to 0°C or -30°C to -10°C, or the H2O precursor reservoir at -50°C to -20°C or -40°C to -30°C. A seventh test series corresponded to the parameters of the sixth test series mentioned here, with the addition of nitrogen dioxide (at a gas flow rate of 1.2 sccm). The test series that included nitrogen dioxide and water as additive gases showed a sharper edge image of the etched structures in a scanning electron microscope image.Furthermore, it should be mentioned that for the method for processing the second example of the specific layer structure, the frame refresh time can also range from 0.1 to 10 ms, preferably 0.2 to 5 ms, particularly preferably 0.5 to 2 ms, wherein the gas chopping ratio can also be selected in the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20.

[0126] In the test series described here, the intensity of the signal of the electrons emitted from the work area was determined during the process (i.e. during the removal of the first and second materials, as well as during processing of the third material with the particle beam). The intensity was determined as a function of the dose of the particle beam (in the examples, an electron beam). The dose corresponded to the dose that was introduced over the area to be etched (the work area) throughout the process, with the intensity being determined using a backscattered electron detector. It was determined that the intensity depends on the material on which the particle beam acts. A specific value (or range of values) of the intensity could be assigned to a specific material or layer of the specific layer structure.The intensity curve as a function of dose thus made it possible to track the removal of the various layers of the specific layer structure. For example, in the case of a (significant) change in intensity (e.g., a local positive and / or negative increase in the intensity curve), it could be concluded that the removal resulted in a change from a previously exposed layer to another (underlying) layer, which is now also exposed but causes a different intensity signal of the electrons. For example, the material of the previously exposed layer could be detected with an intensity I. X be detected, and the material of the other layer with an intensity I Y be detected, with I Y < I X (or I Y > I X ). In a transition phase, a decreasing (increasing) intensity could be observed between I X and I ywere detected, which caused the decrease (increase) in the intensity curve. Furthermore, a (predominantly) constant intensity curve could be used to conclude, for example, that an exposed layer was being processed. This could be attributed to the fact that no (significant) change in intensity was detectable that could be explained by a change in the exposed material. These characteristic properties of the intensity curve, which are associated, for example, with the change in the exposed layer or with the processing of an exposed layer, can be used to determine an endpoint of the process.

[0127] In addition, for the test series described here (i.e. test series one to seven), a corresponding etching depth was determined depending on the selected (introduced) dose of the particle beam. For this purpose, several geometrically identical test structures (or identical test surfaces / working areas to be etched) were exposed to the corresponding process for one test series, with only the (introduced) dose differing for the various test structures. This made it possible to assess the influence of the (introduced) dose of the particle beam for the corresponding processes. The etching depths of the test structures were determined using atomic force microscopy. This information was used to plot the etching depth as a function of the (introduced) dose for the corresponding processes, with the etching depth being plotted on the ordinate and the selected (introduced) dose on the abscissa.The etch depth profile also allowed conclusions to be drawn about the specific layer structure. The (local) increases in the etch depth profile were determined using a linear regression, with the (local) increase corresponding to an etch rate. Due to material-specific differences, the different materials of the specific layer structure also exhibit different etch rates. These differences in etch rates made it possible to determine which characteristic section of the etch depth profile can be assigned to the first layer, the second layer, or the top layer.

[0128] Accordingly, in one example, method 200 includes determining an endpoint of the method based on a specific etch rate (or a specific difference between the etch rates) and / or a specific intensity profile of the electron signal. Determining the etch rate and / or the intensity profile (as described herein) can be performed, for example, before the actual removal of the first material (e.g., as part of a calibration experiment).

[0129] It is also conceivable that the specific layer structure is defined by further layers. For example, it is conceivable that at least one buffer layer is present between the cover layer and the first layer. The buffer layer can have the features of the buffer layer P described herein. Fig. 3a-c. In this context, the buffer layer of the specific layer structure can correspond to the intermediate material (as described herein). The specific layer structure can also be designed such that, in addition to the first and second layers, at least a third layer is present, wherein the third layer can constitute an absorption layer of the pattern element. Thus, for example, a pattern element with three or more absorption layers can be designed on the object for lithography. For example, the first and second layers can be applied alternately to the cover layer (e.g., the layer sequence can include cover layer, first layer, second layer, first layer, second layer, etc.).

[0130] It should be noted that the ruthenium-containing absorption layers mentioned herein may comprise ruthenium and at least one of the following metals: Nb, Zr, Y, B, Ti, La, Mo, Co, Re. Furthermore, the ruthenium-containing material may comprise at least one of the following: N, O, H, C.

[0131] Furthermore, the ruthenium-containing material may comprise at least one of the following transition metals: Mo, Ta, W, Ti, Cr, Hf, Ni, V, Zr, Rh, Nb, Pd. In another example, the ruthenium-containing material may further comprise: Cr, Ni, Co, V, Nb, Mo, W, Re, Ta.

[0132] In principle, it may also be necessary to produce or deposit material (as repair material) during a mask repair. In mask repair using electron beam-induced deposition of ruthenium (e.g., in the form of Ru a Z b, as described herein), ruthenium oxides or other ruthenium-containing deposits, unwanted material deposition can also occur. The unwanted material deposition can be caused, for example, by beam tails of the electron beam and the secondary electrons generated thereby. Furthermore, the unwanted deposition (of the repair material) can be caused by secondary electrons generated at locations in the vicinity of the repaired defect, as well as by secondary electrons that escape at vertical edges of the processed material and propagate to locations in the vicinity of the repaired defect. Likewise, forward scattered electrons (FSE) that escape from the flanks of already existing material and backscattered electrons (BSE) that escape from the surface in the vicinity of the repaired location can contribute to unwanted material deposition.

[0133] A further application of method 200 is therefore the removal of material deposited by these mechanisms on surfaces adjacent to the repaired defect. In one example, method 200 therefore also includes creating a repair material.

[0134] During the production of the repair material, a deposition gas can be used in the electron beam-induced deposition. At least one of the following can be included as a deposition gas in the invention: (Metal, transition element, main group) alkyls such as cyclopentadienyl (Cp)- or methylcyclopentadienyl (MeCp)-trimethylplatinum (CpPtMe3 or MeCpPtMe3), tetramethyltin SnMe4, trimethylgallium GaMe3, ferrocene Cp2Fe, bis-arylchromium Ar2Cr, ruthenocene Cp2Ru, and other such compounds. Furthermore, at least one of the following can be included as the first gas in the invention: (Metal, transition element, main group) carbonyls such as chromium hexacarbonyl Cr(CO)6, molybdenum hexacarbonyl Mo(CO)6, tungsten hexacarbonyl W(CO)6, dicobalt octacarbonyl Co2(CO)8, triruthenium dodecacarbonyl Ru3(CO) 12 , iron pentacarbonyl Fe(CO)5, and other such compounds. Furthermore, one of the following can be included as the first gas in the invention: (metal, transition element, main group) alkoxides such as tetraethoxysilane Si(OC2H5)4, tetraisopropoxytitanium Ti(OC3H7)4, and other such compounds.

[0135] Furthermore, at least one of the following can be included as a deposition gas in the invention: (metal, transition element, main group) halides such as WF6, WCl6, TiCl6, BCl3, SiCl4, and other such compounds. Furthermore, at least one of the following can be included as a deposition gas in the invention: (metal, transition element, main group) complexes such as copper bishexafluoroacetylacetonate Cu(C5F6HO2)2, dimethyl gold trifluoroacetylacetonate Me2Au(C5F3H4O2), dicarbonyl bis-diketonate ruthenium, and other such compounds. Furthermore, one of the following can be included as a deposition gas in the invention: organic compounds such as CO, CO2, aliphatic or aromatic hydrocarbons, components of vacuum pump oil, volatile organic compounds, and other such compounds.

[0136] The method 200 (or the method of the first aspect) can be carried out via the device according to the invention described herein. In one example, the device comprises a mask repair device for repairing or processing lithographic masks. The device can be used to locate mask defects and to repair or eliminate them. The device can comprise parts such as the device described in US 2020 / 0103751 A1 (see corresponding Fig. 3A). The device can, for example, comprise a control unit, which can, for example, be part of a computer system. In one example, the device can be configured such that the computer system and / or the control unit monitors or controls the process parameters of the method of the first aspect disclosed herein. This configuration can enable the method according to the invention mentioned herein to run in a targeted manner as well as in an automated manner, e.g., without manual intervention. This configuration of the device can, for example, be implemented or enabled via the computer program according to the invention described herein.

[0137] Fig. 4 shows a schematic cross-sectional view of an exemplary device 400 according to the invention. The device 400 can be configured to carry out the method 200 or a method of the first and / or second aspect of the invention. In one example, the device 400 of the Fig. 4 shows a mask repair device for repairing or processing lithographic masks. Device 400 can be used to locate mask defects and repair or correct them.

[0138] The exemplary device 400 of the Fig. 4 may, for example, comprise a scanning electron microscope (SEM) 101 for providing a particle beam, which in this example is an electron beam 409. An electron gun 406 may generate the electron beam 409, which may be directed by one or more beam-shaping elements 408 as a focused electron beam 110 onto a lithographic mask 402 arranged on a sample table 404 (or stage, chuck). Furthermore, parameters / properties of the electron beam (e.g., acceleration voltage, dwell time, current intensity, focusing, spot size, etc.) may be specifically adjusted via the scanning electron microscope. The parameters of the electron beam may, for example, be adjusted with respect to a parameter space of the methods described herein. The electron beam 409 may serve as an energy source for initiating a local chemical reaction on a working area of ​​the lithographic mask 402.This can be used, for example, for the methods described herein (e.g., for implementing the electron beam-induced etching of the first aspect). Furthermore, the electron beam 409 can be used to capture an image of the lithographic mask 102. The device 400 can comprise one or more detectors 414 for detecting electrons (e.g., secondary electrons, backscattered electrons).

[0139] To perform the respective methods mentioned herein, the exemplary device 400 of the Fig. 4 have at least two storage containers for at least two different processing gases or precursor gases. The first storage container G1 can store the first gas. The second storage container G2 can store the second gas. In some examples, the storage containers G1 and G2 can be temperature-controlled independently of one another. The second gas can also be regarded as an additive gas. Furthermore, in the exemplary device 400, each storage container G1, G2 has its own gas supply system 432, 447, which can end with a nozzle (i.e., nozzle) near the point of impact of the electron beam 410 on the lithographic mask 402. Each storage container G1, G2 can have its own control valve 446, 431 in order to monitor or control the amount of the corresponding gas provided per unit of time, i.e., the gas flow rate of the corresponding gas.This can be done by specifically adjusting the gas flow rate at the point of impact of the electron beam 410. Furthermore, in one example, the device 400 can comprise further reservoirs of additional gases that can be added to the method of the first aspect as one or more (additive) gases (e.g., oxidizing agents, reducing agents, halides as described herein). The device 400 of FIG. Fig. 4 may include a pump system for generating and maintaining a required pressure in the process chamber 485.

[0140] The device 400 may further comprise a control unit (or regulating unit) 418, which may, for example, be part of a computer system 420. In one example, the device 400 may be configured such that the computer system 420 and / or the control unit 418 monitors or controls the process parameters of the methods disclosed herein. This configuration may enable the inventive methods mentioned herein to run in a targeted manner as well as in an automated manner, for example, without manual intervention. This configuration of the device 400 may, for example, be implemented or enabled via the inventive computer program described herein.

Claims

[1] A method (200) for processing an object for lithography comprising: Providing (210) a first gas comprising first molecules; Providing (220) a particle beam on a working area of ​​the object for removing a first material in the working area based at least in part on the first gas; wherein the first material comprises ruthenium; wherein the first material corresponds to a layer material of a pattern element (PE) of the object. [2] The method (200) of claim 1, wherein the first material in the work area is completely removed. [3] The method (200) of claim 1 or 2, wherein the first material is capable of absorbing radiation associated with the object. [4] The method (200) of any one of claims 1 to 3, wherein the first material further comprises at least one second element. [5] The method (200) of claim 4, wherein the second element comprises at least one of the following: a metal, a semiconductor. [6] The method (200) of any one of claims 4 to 5, wherein the second element comprises at least one of the following: tantalum, chromium, nitrogen, oxygen. [7] The method (200) according to any one of claims 4 to 6, wherein the ruthenium forms a chemical compound with the second element. [8] Method (200) according to one of claims 1 to 7, wherein the method is carried out such that a second material which is adjacent to the first material is at least partially exposed in the working area by the removal. [9] The method (200) of claim 8, wherein the first material and the second material differ in at least one element. [10] The method (200) of any one of claims 8 to 9, wherein the second material comprises tantalum and / or a tantalum compound. [11] The method (200) of any one of claims 8 to 10, further comprising removing the second material in the work area. [12] The method (200) of claim 11, wherein the method is performed such that a third material adjacent to the second material is at least partially exposed in the work area by removing the second material. [13] The method (200) of claim 12, wherein the third material comprises ruthenium. [14] The method (200) of any one of claims 12 to 13, wherein the first and third materials comprise the same elements. [15] Method (200) according to one of claims 12 to 14, wherein the second and / or the third material corresponds to a layer material of a pattern element (PE) and / or a material of a cover layer (D) of a reflective layer stack (ML) of the object. [16] The method (200) of any one of claims 1 to 15, wherein the first molecules comprise a halogen atom. [17] The method (200) of any one of claims 1 to 16, wherein the first molecules comprise a noble gas halide. [18] The method (200) of claim 17, wherein the noble gas halide comprises at least one of the following: xenon difluoride, XeF2, xenon dichloride, XeCl2, xenon tetrafluoride, XeF4, xenon hexafluoride, XeF6. [19] The method (200) of any one of claims 1 to 18, further comprising: Providing a second gas comprising second molecules, wherein the removal of the first material is further based at least in part on the second gas. [20] The method (200) of claim 19, wherein a dipole moment associated with the second molecules comprises at least 1.6 D, preferably at least 1.7 D, more preferably at least 1.8 D, most preferably at least 1.82 D. [21] The method (200) according to any one of claims 18 to 20, wherein the second molecules comprise water, H2O, and / or heavy water, D2O. [22] Method (200) according to one of claims 1 to 21, wherein the particle beam is at least partially based on an acceleration voltage of less than 3 kV, preferably less than 1 kV, more preferably less than 0.6 kV. [23] The method (200) of any one of claims 19 to 22, wherein the method is based at least in part on a temperature associated with the first gas and / or second gas, the temperature being below 0°C (273.15 K), preferably below -5°C (268.15 K), more preferably below -10°C (263.15 K), most preferably below -15°C (258.15 K). [24] Method (200) according to one of claims 1 to 23, wherein the particle beam comprises an electron beam (409). [25] Method (200) according to one of claims 1 to 24, wherein the method is carried out in such a way that a defect (1010) of the object is repaired. [26] Method (200) according to one of claims 1 to 25, wherein the object comprises an EUV mask and / or a DUV mask. [27] Apparatus (400) for processing an object (402) for lithography comprising: Means (G1) for providing a first gas; Means (406, 408) for providing a particle beam (409) on a working area of ​​the object (402); Means (418, 420) for executing a computer program; a memory comprising a computer program, the computer program comprising instructions which, when executed by the means (418, 420) for executing a computer program, cause the device to perform a method (200) according to any one of claims 1 to 26. [28] Object (402) for lithography, wherein the object has been processed by a method (200) according to one of claims 1 to 26. [29] A method for processing a semiconductor-based wafer comprising: lithographically transferring a pattern associated with an object for lithography onto the wafer, wherein the object has been processed by a method (200) according to any one of claims 1 to 26. [30] A computer program comprising instructions which, when executed by a computer system, cause the computer system to perform a method according to any one of claims 1 to 26 and / or claim 29.

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