Method and apparatus for particle beam-induced etching of a defect in a photomask for microlithography

Abstract

Method for particle beam-induced etching of a defect (D1) of a photomask (100) for microlithography, comprising the steps: a) Providing (S1) an activating particle beam (114) and a first gaseous component (116) activatable by the particle beam (114) at a surface (118) of the photomask (100) in a region (120) of the defect (D1) for etching the defect (D1), and subsequently b) Providing (S2) a spontaneously oxidizing oxygen-containing second gaseous component (126) at the surface (118) of the photomask (100) in a passivation area (122) encompassing the area (120) of the defect (D1) for passivation of the surface (118).

Description

[0001] The present invention relates to a method and a device for particle beam-induced etching of a defect in a photomask for microlithography.

[0002] Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out using a lithography system, which includes an illumination system and a projection system. The image of a mask (reticule) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a photosensitive layer (photoresist) and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.

[0003] Driven by the pursuit of ever smaller structures in the manufacture of integrated circuits, EUV lithography systems are currently being developed which use light with a wavelength in the range of 0.1 nm to 30 nm, in particular 13.5 nm.

[0004] The photomask (i.e., lithography mask) used in microlithography features microstructures that are projected onto the substrate on a reduced scale. The photomask structures themselves are very small, ranging in size from a few micrometers to a few nanometers. To produce microstructured components with high accuracy using microlithography, the photomasks must also be manufactured with high precision and be free of defects (e.g., faulty structures and impurities). A defect-free photomask is crucial for microlithography because a single photomask is typically used for numerous exposures. Therefore, photomasks undergo extensive inspection for defects, and any defects found are repaired.

[0005] Typical defects in photomasks include the absence of intended structures, for example, due to an unsuccessful etching process, or the presence of unintended structures, such as an etching process that progressed too quickly or acted in the wrong location. These defects can be eliminated by selectively etching excess material or selectively depositing additional material at the appropriate locations, which is possible, for example, using focused electron beam induced processing (FEBIP).

[0006] DE 10 2017 208 114 A1 describes a method for particle beam-induced etching of a photomask for microlithography. In this method, a particle beam, in particular an electron beam, and an etching gas are applied to the area of ​​the photomask to be etched. The particle beam activates a local chemical reaction between a material of the photomask and the etching gas, thereby locally removing material from the photomask.

[0007] Against this background, one object of the present invention is to improve particle beam-induced etching of a defect in a photomask for microlithography.

[0008] According to a first aspect, a method for particle beam-induced etching of a defect in a photomask for microlithography is proposed. The method comprises the following steps: a) Providing an activating particle beam and a first gaseous component activatable by the particle beam at a surface of the photomask in an area of ​​the defect for etching the defect, and subsequently b) Providing a spontaneously oxidizing, oxygen-containing second gaseous component at the surface of the photomask in a passivation area encompassing the area of ​​the defect for passivation of the surface.

[0009] An "oxidizing component" here refers to an oxidizing agent that can oxidize another substance (e.g., a material on the surface of the photomask). In other words, the other substance (e.g., a material on the surface of the photomask) is oxidized by the oxidizing component.

[0010] Consequently, a defect in the photomask can be a) etched (i.e., ablated and / or removed) in a first step a). In a subsequent step b), following the etching of the defect, the repair area can then be passivated using the second gaseous component, which has a spontaneous oxidizing effect and contains oxygen. For example, the second gaseous component is used to chemically modify a surface of the photomask in the passivation area. This chemical modification can, for example, create a passivation layer (e.g., an oxygen-containing layer) in the passivation area. Passivation allows, in particular, the passivation of surfaces of photomask structures (e.g., absorber structures) that were exposed by the etching in step a). This provides better protection for these structures in subsequent processes.Furthermore, spontaneous etching of the structure can occur on the surface exposed during etching without the addition of the second gaseous component. The addition of the second gaseous component can at least partially counteract this spontaneous etching.

[0011] During passivation, for example, reactive species remaining in the vicinity of the repair site (e.g., F, HF, F compounds) can be displaced by adsorption of the second gaseous component onto the surface of the photomask. Furthermore, passivation can also remove species that can serve as starting materials for reactive compounds (e.g., TaO). a F b-Species used as starting material for reactive fluorine compounds, e.g., HF), can be inactivated by a chemical reaction with the second gaseous component. Furthermore, during passivation, molecules at the repair site can be enriched with oxygen, thus sealing the surface at that point. For example, tantaloxyfluorides generated at the repair site can be enriched with oxygen (e.g., Ta a O b F c + O3 → Ta a O d F e , d > b, e < b, if the second gaseous component contains, for example, ozone (O3). This promotes the formation of Ta2O5 and thus seals the surface at the repair site.

[0012] The exposed surface of the structure includes, for example, the surface of a side wall of the structure. A material of the structure includes, for example, tantalum, one or more tantalum compounds, tantalum nitride, and / or tantalum oxide.

[0013] Steps a) and b) are, in particular, two temporally separated process steps. In other words, repair step a) and passivation step b) are two distinct processes that do not run simultaneously. For example, after repair step a) is completed, passivation step b) is executed immediately without any waiting time. Alternatively, a waiting time (e.g., of a few seconds) can be included between the completion of repair step a) and the start of passivation step b).

[0014] The waiting time is, for example, 60 s or less, 30 s or less, 10 s or less, and / or 1 s or less. The passivation step b), i.e., the introduction of the second gaseous component, takes place, for example, over a period of 120 s or less, 100 s or less, 80 s or less, and / or 60 s or less.

[0015] During passivation step b), no particle beam-induced repair (e.g., no particle beam-induced etching) of the photomask takes place. In other words, passivation step b) is a pure passivation step that is free of particle beam-induced etching of the photomask. For example, when the second gaseous component is introduced, the first gaseous component is no longer introduced. However, depending on operational conditions, when the second gaseous component is introduced, the first gaseous component may still be introduced to the surface of the photomask within a (short) gas transition time. After this transition time has elapsed, the first gaseous component is no longer introduced, while the second gaseous component continues to be introduced.For example, when the second gaseous component is introduced, the particle beam is no longer directed towards the area of ​​the defect and no longer hits the photomask in the area of ​​the defect.

[0016] For example, the photomask is provided in a process atmosphere. The process atmosphere is, for example, an atmosphere with a controlled composition and a controlled pressure (which is, for example, in the range of 10 -2 up to 10 -8The process atmosphere is provided, for example, within an evacuated housing. Furthermore, the first gaseous component, which is introduced to the surface of the photomask in the defect area, is also provided, for example, within the process atmosphere. The second gaseous component, which is introduced to the surface of the photomask in the passivation area, is also provided, for example, within the process atmosphere. In the following, the evacuated housing in which the process atmosphere is provided will also be referred to as the "vacuum chamber".

[0017] Steps a) and b) are performed without opening the vacuum chamber. In particular, the photomask remains in the vacuum chamber during steps a) and b).

[0018] In repair step a), the defect is etched, meaning that material is locally removed from the photomask in the area of ​​the defect. This allows a superfluous and / or unwanted structure (e.g., an unwanted absorber structure) in the area of ​​the defect to be etched away.

[0019] Before step a), a repair shape for the defect is determined based on an image of at least part of the photomask. The repair shape is, in particular, a geometric shape of the defect in the image. The repair shape is, for example, subdivided into a number of pixels. Furthermore, the activating particle beam is, for example, sequentially applied to each pixel of the repair shape, i.e., focused on the respective pixel, and thus rasterized across all pixels of the repair shape.

[0020] The defect region corresponds, for example, to the repair shape of the defect. For instance, the particle beam is provided exclusively within the defect region (e.g., within the repair shape). Furthermore, the first gaseous component is provided, for example, at least within the defect region. This implies that the first gaseous component is also provided, for example, in an extended region of the defect that contains the defect region (e.g., the repair shape) and is larger than the defect region (e.g., the repair shape).

[0021] The passivation area, where the second gaseous component is supplied, encompasses (i.e., contains and / or covers) the entire defect area (e.g., the repair mold). The passivation area is, for example, larger (i.e., has a larger surface area) than the defect area.

[0022] In step a), an activating particle beam is directed onto the surface of the photomask in the defect area. The particle beam can, for example, consist of electrons, ions, and / or protons. The use of an electron beam is particularly advantageous because, on the one hand, it can be focused onto a very small area, and on the other hand, the electrons do not cause significant damage to the irradiated surface. Therefore, the resolution achievable with an electron beam is particularly high.

[0023] Furthermore, in step a), the first gaseous component is introduced to the surface of the photomask, at least in the area of ​​the defect. The surface of the photomask is, in particular, a surface on one side of the photomask that is set up for exposure in an EUV lithography system.

[0024] The first gaseous component includes, in particular, an etching gas. The first gaseous component includes, for example, one or more of the following: xenon difluoride (XeF2), xenon tetrafluoride (XeF4), sulfur hexafluoride (SF6), sulfur tetrafluoride (SF4), nitrogen trifluoride (NF3), phosphorus trifluoride (PF3), tungsten hexafluoride (WF6), tungsten hexachloride (WCl6), molybdenum hexafluoride (MoF6), hydrogen fluoride (HF), nitrosyl fluoride (NOF), nitrosyl chloride (NOCl), and / or triphosphorus trinitrogen hexafluoride (P3N3F6).

[0025] The first gaseous component can include other gases besides the etching gas, such as additive gases. These additive gases can contain oxygen-containing gases, halides (e.g., Cl₂, HCl, XeF₂, CF₄, HF, I₂, HI, Br₂, HBr, NOCl, PCl₃, PCl₅, PF₃, and other halogen-containing gases), and / or reducing gases (e.g., H₂, NH₃, CH₄, and other hydrogen-containing gases).

[0026] The first gaseous component, e.g., the etching gas, is activated by the particle beam. This activation converts the first gaseous component, e.g., the etching gas, into a reactive form, which then reacts with a material (e.g., an atom or molecule) on the surface of the photomask to form a volatile compound. In this way, the surface of the photomask is eroded in the area of ​​the defect.

[0027] The photomask for microlithography, for example, is a photomask for use in an EUV lithography system. EUV stands for "extreme ultraviolet" and refers to a wavelength of the working light between 0.1 nm and 30 nm, specifically 13.5 nm. At these wavelengths, reflective optical elements must be used, which also applies to the photomask. In an EUV lithography system, EUV radiation is directed onto the photomask (reticle) by means of a beam shaping and illumination system. The photomask is designed as a reflective photomask. Therefore, the photomask has a layer reflective to EUV radiation, such as a Bragg mirror, as well as a structured absorbing layer ("absorber structures") on the reflective surface. These are also referred to as binary lithography masks. The pattern of the structured absorbing layer (i.e.,The pattern of absorber structures of the photomask is reduced in size and projected onto a wafer using a projection system of the EUV lithography system.

[0028] The photomask for microlithography, for example, comprises a substrate, a reflective multilayer coating arranged on the substrate, and a structured coating placed on top of it. A capping layer can also be placed between the multilayer coating and the structured coating.

[0029] The substrate comprises, for example, silicon dioxide (SiO2), such as quartz glass, and / or a material with particularly low thermal expansion. The multilayer coating comprises, for example, an alternating sequence of molybdenum and silicon layers. The structured coating comprises, for example, tantalum, one or more tantalum compounds, tantalum nitride, tantalum boron nitride, tantalum boron oxide, and / or tantalum oxide. The substrate, the multilayer coating, and / or the structured coating (absorber structures) may also comprise other materials.

[0030] The photomask thus exhibits, for example, absorber areas with absorber structures and reflection areas free of absorber structures on its surface (i.e., on the surface suitable for exposure in the lithography system). Furthermore, the defect consists, for example, of one or more of the absorber structures that are undesirable. With the proposed method, such a defect in the photomask—that is, a defect in the form of unwanted, i.e., superfluous, absorber structures—can be etched away and thus repaired.

[0031] After the defect has been etched, a passivation step is performed in step b). For this, the second gaseous component is introduced to the surface of the photomask in the passivation area to passivate the surface. The second gaseous component is a spontaneously oxidizing, oxygen-containing gaseous component. In other words, the second gaseous component causes a spontaneous oxidation of a material on the surface of the photomask. That is, the second gaseous component triggers a spontaneous chemical reaction with a material on the surface of the photomask. A spontaneous chemical reaction is a chemical reaction that occurs without external constraints, in particular without additional activation (e.g., at room temperature and / or at a temperature between 20° and 22°C and / or at 21°C).In particular, activation of the second gaseous component by a particle beam is not required to achieve the passivation effect of the second gaseous component.

[0032] This is an advantage over non-spontaneously oxidizing species used as passivation gases, which only form a deposit or cause a chemical modification of the substrate under the influence of a particle beam. An example of a non-spontaneously oxidizing species used as a passivation gas is TEOS gas (TEOS stands for tetraethyl orthosilicate (Si(OC2H5)4, also known as tetraethoxysilane)), which only forms a deposit, such as silicon dioxide, under the influence of a particle beam.

[0033] For example, the photomask has a metal-containing material on its surface, and the second gaseous component passivates the metal-containing material spontaneously (e.g., by spontaneous chemical adsorption). The second gaseous component is thus a strongly oxidizing species that can spontaneously oxidize a metal-containing material (i.e., without additional activation, especially without activation by a particle beam) (e.g., transfer oxygen atoms to the metal-containing surface). This is an advantage over, for example, TEOS as a passivation gas, which cannot spontaneously oxidize a metal-containing material.

[0034] For example, a structured coating (absorber structures) of the photomask contains a metal-containing material (e.g., tantalum compounds). Similarly, a capping layer of the photomask contains a metal-containing material (e.g., ruthenium).

[0035] According to one embodiment, in step a) at least one edge of a structured coating of the photomask is exposed. Furthermore, in step b) the at least one exposed edge is passivated.

[0036] In particular, at least one edge of the structured coating that is exposed in step a) is still at least partially exposed at the end of step a).

[0037] The at least one edge of the structured coating is, in particular, at least one edge that is arranged substantially perpendicular to a principal extension plane of the photomask. "Substantially perpendicular" includes angles between the at least one edge of the photomask and the principal extension plane of the photomask of 60° or greater, 70° or greater, 80° or greater, 85° or greater, and / or approximately 90°.

[0038] For example, at least one edge of the structured coating has at least one side wall of the structured coating.

[0039] According to another embodiment, the defect in step a) is completely etched and / or completely removed.

[0040] This allows the defect, i.e., an unwanted structure (e.g., a geometrically coherent unwanted structure), to be completely removed in step a). Thus, the photomask defect is fully repaired before the photomask surface, particularly at the repair site, is passivated.

[0041] According to another embodiment, the second gaseous component passivates the surface of the photomask by means of spontaneous chemical adsorption.

[0042] This means that the second gaseous component chemically adsorbs onto a material on the surface of the photomask. In other words, a chemical reaction takes place between the second gaseous component and a material on the surface of the photomask. This chemically alters the surface material of the photomask. Chemical adsorption is also called chemisorption.

[0043] In detail, for example, the second gaseous component is chemically adsorbed onto a material on the surface of the photomask, and subsequently the surface of the photomask is oxidized by the chemically adsorbed second gaseous component, whereby at least one oxygen atom is irreversibly bound to the surface of the photomask.

[0044] Chemical adsorption differs from physical adsorption ("physisorption") in that chemical adsorption involves a chemical reaction between an adsorbate (here, the second gaseous component) and an adsorbent (here, the surface material of the photomask). This means that the adsorbate and / or adsorbent are chemically modified. In contrast, physical adsorption only creates a physical bond between the adsorbate (second gaseous component) and the adsorbent (surface material of the photomask). That is, the adsorbate and adsorbent are not chemically altered, but rather bound together by physical forces. This physical bond is based, for example, on weak and therefore easily reversible van der Waals forces. An example of physical adsorption is the adsorption of TEOS gas onto the surface of a photomask.TEOS comprises one or more oxygen-containing compounds that form non-volatile oligomers on the mask. These non-volatile oligomers are macromolecules formed from individual TEOS molecules; that is, they are chains of TEOS molecules linked to each other (not to the surface of the photomask). Due to their greater mass (compared to individual TEOS molecules), the TEOS oligomers can physisorb onto the surface of the photomask for a longer period.

[0045] According to another embodiment, the method comprises the following step: c) Pumping the second gaseous component from the surface of the photomask.

[0046] The second gaseous component is, for example, pumped out of the process atmosphere.

[0047] For example, steps a), b) and c) are performed without opening the vacuum chamber. In particular, the photomask remains in the vacuum chamber and in the process atmosphere during steps a), b) and c).

[0048] According to a further embodiment, in step a) a first defect of the photomask is etched in a first region of the photomask. Furthermore, the method according to step c) includes a further step a) in which a second defect of the photomask is etched in a second region of the photomask.

[0049] By passivating the surface of the photomask with the second gaseous component after etching the first defect, the photomask surface is protected for subsequent processing steps. In particular, this prevents the etching process from unintentionally continuing at the repair site of the first defect when etching the second defect (i.e., when repeating step a) for the second defect), which again uses an etching gas.

[0050] The first and second regions of the corresponding first and second defects are, in particular, disjoint regions of the photomask. This means, among other things, that the first and second regions do not overlap and are not connected.

[0051] The first and second areas of the corresponding first and second defects can, for example, each be geometrically connected areas.

[0052] After repeating step b) for the second defect, step c) can also be performed again.

[0053] Steps a) and b) and / or a) to c) can be repeated any number of times for further defects of the photomask, wherein the further areas of the further defects are mutually disjoint to each other and to the first and second areas of the first and second defects.

[0054] For example, the method can be used to etch (e.g., repair) a number n of defects in the photomask, where n is a natural number greater than 1. Steps a) to c) can then be performed for each of the first (n-1) defects, and steps a) and b) can be performed for the nth defect. The photomask can then be removed from the process atmosphere (e.g., taken out of the vacuum chamber and / or unloaded).

[0055] According to another embodiment, the second gaseous component comprises ozone (O3), atomic oxygen (O), excited oxygen (O2*), hydroperoxyl (HOO), hydroxyl (HO), a nitrate radical (NO3), one or more oxygen radicals and / or one or more neutral oxygen radicals.

[0056] Ozone (O3) is a strong oxidizing agent that exerts its oxidizing effect even at room temperature. Due to its strong oxidizing power, the gas is unstable even at room temperature. Ozone's effect arises from the atomic oxygen produced during the decomposition of the molecule (decomposition reaction: O3 → O2 + O), which is itself highly reactive and oxidizing. Ozone, therefore, acts as a carrier of this reactive atomic oxygen, known as "active oxygen." Ozone can, for example, transfer oxygen atoms to metal surfaces. Ozone can also oxidize halides to halogens. Furthermore, ozone has a dipole moment of 0.5337 D, which promotes surface adsorption.

[0057] Oxygen radicals are primarily reactive oxygen species (ROS), e.g., oxygen-containing molecules. In this context, oxygen radicals also include atomic oxygen.

[0058] According to another embodiment, the second gaseous component comprises ozone, which is generated using an ozonator. In the ozonator, oxygen is passed through an electric field or exposed to UV light, so that ozone is produced from the oxygen. The generated ozone is supplied to the surface of the photomask via a supply line of the ozonator and / or via a feed line connected to the ozonator via fluid.

[0059] Oxygen can be supplied to the ozonizer as pure oxygen (O2) or as a component of a molecule (e.g. H2O) or a mixture (e.g. air).

[0060] The ozonizer, for example, has a chamber through which the oxygen is passed and in which the electric field or UV light acts on the oxygen.

[0061] For example, the ozonizer's supply line (e.g., directly) is fluid-connected to the chamber. The supply line has, for instance, a nozzle at its end opposite the chamber, through which the ozone is directed to the surface of the photomask.

[0062] For example, the ozonizer provides an O3 flow of 0.1–4 sccm at its outlet nozzle and / or the surface of the photomask. This relatively low O3 flow ensures compatibility with the vacuum system.

[0063] According to a further embodiment, the second gaseous component comprises one or more neutral oxygen radicals, which are generated using a plasma-based gas generation device. The plasma-based gas generation device includes a plasma source and a selection device fluid-connected to the plasma source. The selection device extracts the one or more neutral oxygen radicals from the plasma generated in the plasma source and supplies them to the surface of the photomask via a supply line of the plasma-based gas generation device and / or via a feed line fluid-connected to the selection device.

[0064] The plasma source (remote plasma source) and the selection device can be used to provide, for example, atomic oxygen (O), hydroperoxyl (HOO), hydroxyl (HO) and / or nitrate radicals NO3, as neutral oxygen radicals and thus a second gaseous component.

[0065] The plasma-based gas generation device, in particular the plasma source, includes, for example, a chamber in which the plasma is generated. The selection device is arranged, for example, at an outlet opening of the chamber. Furthermore, the supply line of the plasma-based gas generation device is fluid-connected to the selection device, for example (e.g., directly). The supply line has, for example, a nozzle at its end opposite the selection device, through which the oxygen radical(s) is / are directed to the surface of the photomask.

[0066] According to a further embodiment, the first gaseous component comprises at least one etching gas component for etching the defect and at least one passivation gas component for passivating the surface of the photomask in a first passivation step. Furthermore, in step b), the surface of the photomask is passivated using the second gaseous component in a second passivation step.

[0067] In this embodiment, in addition to passivation step b), a further passivation step is performed using the second gaseous component during etching step a). In other words, in step a), the defect is etched using the first gaseous component, and the repair area is simultaneously passivated in a first passivation step. Subsequently, in step b), a second passivation step is performed using the second gaseous component.

[0068] In particular, the first passivation step performed during step a) may not result in complete passivation of the photomask surface. For example, passivation at the edges of the absorber structures may be incomplete. The second, subsequent passivation step b) can then improve and / or complete the surface passivation.

[0069] The passivation gas component, which in this embodiment is contained in the first gaseous component, comprises, for example, one or more of the following substances: oxygen (O2), ozone (O3), water (H2O), hydrogen peroxide (H2O2), nitrous oxide (N2O), nitrogen monoxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3) and other oxygen-containing gases.

[0070] According to another embodiment, step b) shows that: a third gaseous component is provided on the surface of the photomask in the passivation area, The third gaseous component passivates the photomask in the passivation region by physical adsorption, and The second and third gaseous components can be provided simultaneously in a single passivation step or sequentially in two passivation steps separated by time.

[0071] In this embodiment, in step b), in addition to the passivation step using the second gaseous component, a further passivation step is performed using a third gaseous component. While the passivation step using the second gaseous component is a passivation by chemisorption, the further passivation step using the third gaseous component is a passivation by physisorption. This allows for a further improvement in the passivation of the photomask surface.

[0072] If the second and third gaseous components are provided simultaneously in a single passivation step, the second and third gaseous components can, for example, be provided as a gas mixture.

[0073] If the second and third gaseous components are provided sequentially in two passivation steps separated by time, for example, the third gaseous component is first provided for physical passivation and then the second gaseous component for chemical passivation.

[0074] If an additional passivation step is carried out in step a), the process can thus comprise three different passivation steps, e.g. with three different gases.

[0075] The third gaseous component includes, by way of example only, NO2 and / or TEOS. However, the third gaseous component could also include one or more other gases.

[0076] According to another embodiment: The photomask has absorber areas with absorber structures and reflection areas that are free of absorber structures. The defect exhibits one or more of the undesirable absorber structures, which are etched in step a) using the first gaseous component. In step b), a fourth gaseous component is provided at the surface of the photomask, The photomask in the reflection areas is protected from passivation by the second gaseous component by means of the fourth gaseous component, and The photomask is passivated in the absorber areas using the second gaseous component.

[0077] The fourth gaseous component protects the reflection areas of the photomask from passivation by the second gaseous component. These reflection areas include, for example, a capping layer. This capping layer may contain, for example, ruthenium (Ru capping layer). The capping layer can be damaged by the strong oxidizing effect of the second gaseous component. To prevent this, the fourth gaseous component protects the photomask in the reflection areas from passivation (i.e., oxidation) by the second gaseous component. The fourth gaseous component, for example, adsorbs physically into the reflection areas of the photomask.

[0078] The fourth gaseous component includes, for example, TEOS, tetrafluoromethane (CF4) and / or nitrogen dioxide (NO2). The fourth gaseous component may also include one or more other substances.

[0079] According to a second aspect, a device for particle beam-induced etching of a defect in a photomask for microlithography is proposed. The device features: a first delivery device for delivering an activating particle beam to a surface of the photomask in an area of ​​the defect, a second delivery device for providing a first gaseous component, activatable by the particle beam, at the surface in the area of ​​the defect for etching the defect, and a third provisioning device for providing a spontaneously oxidizing oxygen-containing second gaseous component at the surface in a passivation area of ​​the photomask encompassing the area of ​​the defect for passivation of the surface.

[0080] The device is, for example, a repair device for repairing photomasks for microlithography. The device is, for example, a modified scanning electron microscope.

[0081] The first provisioning device comprises, for example, a particle source (e.g., electron source) for generating the particle beam (e.g., electron beam); a particle beam guidance device (e.g., scan unit) configured to direct the particle beam onto a respective pixel of the photomask repair pattern; a particle beam shaping device (e.g., particle, electron, and / or beam optics) configured to shape the particle beam, in particular to focus it; and at least one detector for detecting secondary electrons and / or backscattered electrons.

[0082] The second and third supply units are, in particular, a second and third gas supply unit. The second and third supply units can, for example, both be part of a higher-level gas supply device. Each of the second and third gas supply units comprises at least one storage container configured to store the corresponding gaseous component and / or a gas generation unit configured to generate the corresponding gaseous component in situ; a gas flow control unit configured to supply the corresponding gaseous component at a predetermined gas flow rate to the surface of the photomask in the corresponding area (e.g., also one or more valves); a feed unit (e.g., a pump, a gas supply unit, etc.).with a supply line), which is designed to supply the appropriate gaseous component to the surface of the photomask.

[0083] In step a), the activating particle beam is sequentially delivered to each pixel of the repair mold, for example, using the particle beam guidance device. The activating particle beam remains at each pixel for a predetermined dwell time to initiate the chemical reaction between the first gaseous component and the mask material at the location of the respective pixel. The dwell time is, for example, 100 ns. However, the dwell time can also be set to other values.

[0084] According to one embodiment of the second aspect, the device has: an ozonizer for generating ozone from oxygen, wherein the ozonizer comprises a capacitor for generating an electric field or a UV light source for generating UV light, and a supply line for delivering the generated ozone as the second gaseous component to the surface of the photomask.

[0085] According to a further embodiment of the second aspect, the device includes a plasma-based gas generation unit for generating the second gaseous component. The plasma-based gas generation unit comprises a plasma source for generating a plasma, a selection unit for decoupling one or more neutral oxygen radicals from the plasma, and a delivery line for supplying the one or more decoupled neutral oxygen radicals to the surface of the photomask.

[0086] The plasma is generated, for example, from oxygen. Specifically, the plasma is generated in a plasma chamber of the plasma source and exists only within that chamber. One or more neutral oxygen radicals are then extracted from the plasma using a selection device.

[0087] The second gaseous component can be generated in situ at the location of the particle beam-induced etching device by means of the ozonizer or the plasma-based gas generation device.

[0088] The term "one" here is not necessarily to be understood as restricting the number to exactly one element. Rather, it can also refer to multiple elements, such as two, three, or more. Similarly, every other counter used here should not be interpreted as restricting the number to the exact number stated. Instead, numerical deviations, both higher and lower, are possible unless otherwise specified.

[0089] The embodiments and features described for the method apply accordingly to the proposed device and vice versa.

[0090] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0091] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below with reference to preferred embodiments and the accompanying figures. Fig. Figure 1 shows, according to one embodiment, a schematic section through a photomask for microlithography which is subjected to a particle beam-induced processing process, wherein the upper figure illustrates a particle beam-induced repair process of a defect and the lower figure illustrates passivation of the repair site; Fig. Figure 2 shows a flow diagram of a process for particle beam-induced etching of a defect in a photomask for microlithography according to one embodiment; Fig. Figure 3 shows a device for particle beam-induced etching of a defect in a photomask for microlithography according to one embodiment; Fig. Figure 4 shows a gas generation unit of the device made of Fig. 3 according to one embodiment; Fig. Figure 5 shows a gas generation unit of the device made of Fig. 3 according to a further embodiment; Fig. Figure 6 shows a photomask for microlithography in a top view according to one embodiment; Fig. Figure 7 illustrates variants of the process steps from Fig. 2; and Fig. Figure 8 shows a device for particle beam-induced etching of a defect in a photomask for microlithography according to a further embodiment.

[0092] In the figures, identical or functionally equivalent elements have been labelled with the same reference symbols, unless otherwise indicated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0093] Fig. Figure 1 schematically shows a cross-section through a photomask 100 that is subjected to a particle beam-induced processing process. This is, in particular, a locally induced etching process in which material is removed from the photomask 100.

[0094] The example shown for photomask 100 is a mask suitable for EUV lithography and operates on a reflective basis. This means that the working light shines onto photomask 100 during operation and is reflected back into the same hemisphere. EUV stands for "extreme ultraviolet" and refers to a wavelength of the working light between 0.1 nm and 30 nm, specifically 13.5 nm.

[0095] In the example of Fig. The photomask 100 has a layered structure. A substrate 102, which may, for example, be quartz glass, forms the base of the photomask 100. A multilayer mirror 104 is arranged on the substrate 102. The multilayer mirror 104 is specifically located on the side of the substrate 102 that will later be illuminated by the operating light. The multilayer mirror 104 is, for example, a Bragg mirror specifically designed for the respective wavelength of the operating light. The multilayer mirror 104 has, for example, a plurality of double layers of molybdenum and silicon. A capping layer 106 is arranged on the multilayer mirror 104. The capping layer 106 contains, for example, ruthenium or another precious metal.The cover layer 106, for example, is an etch stop layer, which is designed to stop etching processes used in the structuring of the structured layer 108, so that the multilayer mirror 104 or the substrate 102 is not attacked.

[0096] A structured layer 108 is arranged on the cover layer 106. The pattern of this layer is to be projected onto a wafer in an image plane of a projection system in the lithography unit. The reference numeral 110 designates several structures of the structured layer 108. The structured layer 108 comprises, for example, tantalum boron nitride (TaBN), tantalum nitride (TaN), tantalum boron oxide (TaBO), and / or tantalum oxide (TaO). To create the structured layer 108, a layer of TaBN is first applied over the entire surface and then selectively etched. In areas where the TaBN layer remains, the incident working light is strongly attenuated.

[0097] Defects D1 can occur during the production of photomask 100. Fig. Figure 1 shows an opaque defect D1 in which an absorber structure 112 is arranged at a location on the photomask 100 where none should be. In other words, the absorber structures 110 in Fig. 1 desired absorber structures, while absorber structure 112 is an undesirable and superfluous absorber structure.

[0098] The following describes a method for particle beam-induced etching of a defect D1 of a photomask 100 for microlithography with reference to the Fig. 1 to 8, in particular Fig. 2, described.

[0099] In the first step S1 of the process, the defect D1 is etched in a particle beam-induced process. The first step S1 is shown in the figure above. Fig. Figure 1 illustrates this. In step S1, in particular, an activating particle beam 114 (e.g., an electron beam) and a first gaseous component 116, which can be activated by the particle beam 114, are provided at a surface 118 of the photomask 100 in a region 120 of the defect D1. The first gaseous component 116 comprises, in particular, an etching gas such as XeF2.

[0100] For example, when etching defect D1 in step S1, one or more edges 124 ( Fig. 1 below) of structures 108 exposed.

[0101] For example, defect D1 can be completely etched, i.e., completely removed, in step S1. In this case, the unwanted structure 112 is completely removed at the end of step S1.

[0102] In a second step S2 of the process, the surface 118 of the photomask 100 is passivated in a passivation area 122. The second step S2 is performed following the first step S1, in which the defect D1 is etched. The second step S2 is shown in the lower figure. Fig. Figure 1 illustrates the photomask 100 without the defect D1, 112.

[0103] In particular, in step S2, a second gaseous component 126 is provided at the surface 118 of the photomask 100 in the passivation area 122 of the photomask 100. The passivation area 122 comprises the area of ​​the defect 120 ( Fig. 1 above) in particular completely and is, for example, larger than this one. The second gaseous component 126 is a spontaneously oxidizing oxygen-containing gaseous component. The second gaseous component 126 has a highly reactive species, such as ozone or another oxygen radical, and passivates the surface 118 of the photomask 100 without additional activation, i.e., without activation by a particle beam (e.g., without the one shown in the figure above). Fig. 1 particle beam 114). In particular, the second gaseous component 126 passivates the surface 118 of the photomask 100 by spontaneous chemical adsorption, chemically modifying the surface 118. The second gaseous component 126 is specifically designed to spontaneously (i.e., without activation by a particle beam) oxidize a metal-containing material on the surface 118 of the photomask 100, such as a metal-containing material (e.g., a tantalum compound and / or tantalum) of the structured coating 108.

[0104] By passivating in step S2, in particular exposed surfaces 118' of edges 124 of the structures 108 that were exposed during etching in step S1 can be passivated.

[0105] Fig. Figure 3 shows a schematic drawing of a device 200 for particle beam-induced etching of a photomask 100, for example the EUV photomask 100 made of Fig. 1.

[0106] The device 200 has a housing 202 which is pressurized by a vacuum pump 204 to a pressure in the range of 10 -2 - 10 -8 The vacuum chamber 200 is evacuated to a pressure of mbar to create a process atmosphere 206 within the housing 202. The device 200 also includes a delivery unit 208 arranged within the vacuum housing 202 for providing a focused particle beam 114. The delivery unit 208 comprises a particle source 210 and one or more beam-guiding and / or beam-shaping units 212, 214, which direct the particle beam 114 onto the surface 118 of the photomask 100 in the desired manner. For example, the delivery unit 208 is an electron column configured to provide a focused electron beam 114. The device 200 also includes one or more detectors 216, e.g., for detecting secondary electrons.

[0107] The device 200 also includes a sample stage 218 for holding and positioning the photomask 100 to be processed. The sample stage 218 can be actuated in two or preferably three spatial directions. Furthermore, the sample stage 218 can be mounted to tilt and rotate in order to position the photomask 100. The sample stage 218 is, in particular, mounted with vibration damping and mechanically decoupled from the rest of the assembly (not shown).

[0108] Furthermore, the device 200 comprises a first and a second gas supply unit 220, 222 for supplying the first and second gaseous components 116, 126. The first and second gas supply units 220, 222 are, for example, partially located outside the housing 202. Each of the first and second gas supply units 220, 222 comprises at least one storage container 224, 226 or a gas generation unit 224, 226. Each of the first and second gas supply units 220, 222 also comprises means for adjusting a gas flow rate and means for initiating and terminating a gas flow. Furthermore, each of the first and second gas supply devices 220, 222 has a supply line 228, 230 which leads into the housing 202 and opens at its end into a respective nozzle.In addition, further gas supply facilities similar to the gas supply facilities 220, 222 may be provided to supply further gaseous components, such as buffer gases, oxidizing or reducing gases, into the process atmosphere 206.

[0109] In Fig. Figure 3 also shows an extraction unit 232. The extraction unit 232 is designed to extract excess gas and, in particular, volatile reaction products from the process atmosphere 206, especially from the surface 118 of the photomask 100. The extraction unit 232 includes, for example, an additional pump 234. This allows for better control of the composition of the process atmosphere 206.

[0110] In the Fig. 4 and Fig. Figure 5 illustrates embodiments of the second gas generation device 226', 226" for generating the second gaseous component 126, 126', 126". The second gaseous component 126, 126', 126" is, in particular, a highly reactive species that is preferably generated adjacent to its point of use.

[0111] In Fig. Figure 4 shows an ozonator 236 for generating ozone O3 as a second gaseous component 126'. The ozonator 236 includes a feed line 238 for supplying oxygen O2. Oxygen O2 can be supplied to the ozonator 236 as pure oxygen O2 or as a component of a molecule (e.g., H2O) or a mixture (e.g., air). The ozonator 236 further includes a chamber 240 in which the oxygen O2 is exposed, for example, to a strong electric field E (capacitor 242), causing ozone O3 to form from the oxygen O2. The ozonator 236 also includes a supply line 244 for supplying the generated ozone O3. The supply line 244 is, for example, the one shown in Figure 240. Fig. 3. Supply line 230 shown for supplying the second gaseous component 126, 126' to the photomask 100. Alternatively, the supply line 244 is connected to the supply line 230 in Fig. 3 fluid-connected.

[0112] In Fig. Figure 5 shows a plasma-based gas generation device 246 for generating one or more neutral oxygen radicals 248 as a second gaseous component 126. The plasma-based gas generation device 246 comprises a feed channel 250 for supplying a working gas 251 (e.g., oxygen) into a chamber 252, the chamber 252 with a plasma source 254 for generating a plasma, a selection device 256 for extracting the one or more neutral oxygen radicals 248 from the plasma, and a supply line 258 for supplying the generated neutral oxygen radicals 248. The supply line 258 is, for example, the one shown in Figure 5. Fig. 3. Supply line 230 shown for supplying the second gaseous component 126, 126" to the photomask 100. Alternatively, the supply line 258 is connected to the supply line 230 in Fig. 3 fluid-connected. With the plasma-based gas generation device 246, for example atomic oxygen (O), hydroperoxyl (HOO), hydroxyl (HO) and / or NO3, as neutral oxygen radicals 248 and thus a second gaseous component 126", can be provided.

[0113] In an optional third step S3 of the process, the second gaseous component 126 is pumped off from the surface 118, 118' of the photomask 100. For example, the gaseous component 126 is used for this purpose. Fig. The suction unit 232 shown is used with the additional pump 234.

[0114] In an optional fourth step S4 of the procedure, step S1 is repeated after step S3 - but for a different second defect D2 of the photomask ( Fig. 6) - executed.

[0115] In particular, during the first execution of step S1, a first defect D1 of the photomask 100 is etched in a first area 120 of the photomask 100 ( Fig. 1, Fig. 6) Furthermore, the surface 118 of the photomask 100 (e.g., the surface 118' of exposed edges 124 of the structures 108, Fig. 1) passivated in a first execution of step S2. Then step S3 is carried out and the second gaseous component 126 is pumped off from the surface 118, 118' of the photomask 100. Subsequently, the second defect D2 ( Fig. 6) the photomask 100 in a second area 130 of the photomask 100 in a second execution of step S1.

[0116] Optionally, step S2 for passivating the surface 118 of the photomask 100 can be repeated for a second passivation area 132 ( Fig. 6), which includes the second area 130 of the second defect D2, will be executed.

[0117] Similarly, by repeatedly performing steps S1 and S2 or S1 to S3, several other defects (not shown) of the photomask 100, which are similar to defects D1, D2, can be etched and the corresponding repair sites passivated.

[0118] Steps S1 to S3, including possible repetitions of steps S1 and S2 or S1 and S3 for further defects, are performed, for example, without removing the photomask 100 from the process atmosphere 206. In other words, the photomask 100 remains in the vacuum chamber 202 during these process steps, and the vacuum chamber 202 remains closed.

[0119] In Fig. Figure 7 illustrates variants of process steps S1 and S2.

[0120] In a first variant of the process, process step S1 can, in addition to the etching step described above (hereinafter referred to as step S11), include a passivation step S12 for passivating the surface 118 of the photomask 100. This means that the process comprises two independent passivation steps. In particular, the process includes a pre-passivation step S12 with a pre-passivation gas 318 during etching S11 ( Fig. 8) and a main passivation step S2 (or S22) with a main passivation gas 126 after etching S11.

[0121] In the first variant of the method, the first gaseous component 316 (see device 300 in Fig. 8) In addition to an etching gas 318 for etching the defect D1, at least one passivation gas 320 is used for passivating the surface 118 of the photomask 100. The passivation gas 320 comprises, for example, H2O. The passivation gas 320 is, for example, a passivation gas that only has a passivating effect when activated by a particle beam 114.

[0122] In this first variant of the process, the defect D1 is etched in step S1 (specifically in substep S11) using the first gaseous component 316 (with the etching gas 318), and simultaneously the repair area is passivated in a first pre-passivation step S12 (with the passivation gas 320). Subsequently, a second passivation step is carried out in step S2 using the second gaseous component 126.

[0123] In particular, if the pre-passivation step S12 does not lead to a complete passivation of the surface 118, 118' of the photomask 100 and, for example, the passivation at edges 124 ( Fig. 1) if the absorber structures 108 are incomplete, the passivation of the surface 118 can advantageously be completed with the second downstream main passivation step S2.

[0124] In a second variant of the process, process step S2 can include a step S21 for generating the second gaseous component 126, 126', 126". In particular, the second gaseous component 126, 126', 126" is generated in situ at the location of the device 200, 300. For example, the second gaseous component 126, 126', 126" is generated using an ozonizer 236 ( Fig. 4) or with a plasma-based gas generation device 246 ( Fig. 5) generated.

[0125] In a third variant of the process, process step S2 can include a further passivation step S23. In this case, process step S2 comprises two passivation processes S22 and S23: In addition to the passivation process described above using the second gaseous component 126, 126', 126" (hereinafter referred to as S22), a further passivation process S23 is carried out using a third gaseous component 326.

[0126] In particular, the third gaseous component 326 is provided at the surface 118 of the photomask 100 in the passivation area 122, which includes the defect area 120. The third gaseous component 326 passivates the photomask 100 in the passivation area 122 by physical adsorption. The third gaseous component 326 includes, for example, NO2 and / or TEOS. By passivating the surface 118 of the photomask 100 at the repair site using the second gaseous component 126 based on chemisorption of the surface 118 and additionally by passivating it using the third gaseous component 326 based on physisorption, the passivation can be further improved by

[0127] In the third variant of the process, the second and third gaseous components 126, 326 can be provided simultaneously in a single passivation step S22+S23, for example, as a gas mixture (e.g., two-thirds of the second gaseous component 126 and one-third of the third gaseous component 326, or another mixing ratio). Alternatively, the second and third gaseous components 126, 326 can also be provided sequentially in two separate passivation steps S22, S23. In this case, for example, the third gaseous component 326 is provided first for physical passivation, and then the second gaseous component 126 is provided for chemical passivation. However, the reverse order is also possible.

[0128] If the additional passivation step S12 is carried out, the process can therefore comprise three different passivation processes / steps S12, S22, S23 with three different passivation gases 126, 320, 326.

[0129] In a fourth variant of the process, process step S2 can include a step S24 in which a fourth gaseous component 426 is supplied to the surface 118 of the photomask 100 in order to define areas R ( Fig. 6) to protect the photomask 100, which is not to be passivated, from passivation by the second gaseous component 126.

[0130] In particular, the photomask has 100 absorber areas A with absorber structures 108 and reflection areas R that are free of the absorber structures 108 ( Fig. 6) The reflection areas R, for example, have a surface area of ​​118" of the cover layer 106 ( Fig. 1). Furthermore, the defect D1 exhibits one or more of the absorber structures 108, 110, in particular undesired absorber structures 112 ( Fig. 1) These unwanted absorber structures 112 are etched in step S1 using the first gaseous components 126. In step S2, both the first gaseous component 126 (in substep S22) and the fourth gaseous component 426 (in substep S24) are then provided at the surface 118, 118', 118" of the photomask 100. This protects the photomask 100 in the reflection regions R from passivation by the second gaseous component 126, e.g., by physical adsorption of the fourth gaseous component 426 in the reflection regions R. Furthermore, the photomask is passivated in the absorber regions A using the second gaseous component 126.

[0131] Individual, several or all of the first to fourth variants of the procedure can also be combined with each other.

[0132] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. REFERENCE MARK LIST 100 Photomasks 102 Substrat 104 Multilayer mirrors 106 Cover layer 108 shifts 110, 112 Absorber structure 114 particle beam 116 Component 118, 118', 118" surface 120 area Area 122 124 edge 126, 126', 126" component 130 area 132 area 200 Device 202 cases 204 Vacuum pump 206 Process atmosphere 208 Provisioning facility 210 particle source 212, 214 Unit 216 Detector 218 Sample table 220, 222 Gas supply unit 224, 226 Storage tank / gas generation plant 226', 226" Gas generating plant 228 Supply line 230 Supply line 232 Extraction unit 234 Pump 236 Ozonizer 238 Supply line 240 Chamber 242 Capacitor 244 Deployment line 246 Gas generating plant 248 Oxygen radical 250 feed channel 251 Working gas 252 Chamber 254 Plasma source 256 Selection facility 258 Provisioning line 300 device 316 Component 318 Gas 320 Gas 326, 426 component Area D1, D2 Defect E electric field O2 Oxygen R area S1 - S4 process steps S11, S12 Procedure steps S21 - S24 procedural steps QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 208 114 A1

[0006]

Claims

[1] Method for particle beam-induced etching of a defect (D1) of a photomask (100) for microlithography, comprising the steps: a) Providing (S1) an activating particle beam (114) and a first gaseous component (116) activatable by the particle beam (114) at a surface (118) of the photomask (100) in a region (120) of the defect (D1) for etching the defect (D1), and subsequently b) Providing (S2) a spontaneously oxidizing oxygen-containing second gaseous component (126) at the surface (118) of the photomask (100) in a passivation area (122) encompassing the area (120) of the defect (D1) for passivation of the surface (118). [2] Method according to claim 1, wherein in step a) at least one edge (124) of a structured coating (108) of the photomask (100) is exposed, and the at least one exposed edge (124) is passivated in step b). [3] Method according to claim 1 or 2, wherein the defect (D1) is completely etched and / or completely removed in step a). [4] Method according to any one of claims 1 to 3, wherein the second gaseous component (126) passivates the surface (118) of the photomask (100) by means of spontaneous chemical adsorption. [5] Method according to any one of claims 1 to 4, comprising a step: c) Pumping (S3) the second gaseous component (126) from the surface (118) of the photomask (100). [6] Method according to claim 5, wherein in step a) a first defect (D1) of the photomask (100) is etched in a first area (120) of the photomask (100), and the procedure according to step c) includes a further step a) in which a second defect (D2) of the photomask (100) is etched in a second area (130) of the photomask (100). [7] Method according to any one of claims 1 to 6, wherein the second gaseous component (126) comprises ozone (O3), atomic oxygen (O), excited oxygen (O2*), hydroperoxyl (HOO), hydroxyl (HO), a nitrate radical NO3, one or more oxygen radicals (248) and / or one or more neutral oxygen radicals (248). [8] Method according to any one of claims 1 to 7, wherein the second gaseous component (126) ozone (O3) which is produced using an ozonator (236), in the ozonizer (236) oxygen (O2) is passed through an electric field (E) or exposed to UV light, so that ozone (O3) is produced from the oxygen (O2), and The generated ozone (O3) is supplied to the surface (118) of the photomask (100) via a supply line (244) of the ozonizer (236) and / or via a supply line (230) fluid-connected to the ozonizer (236). [9] Method according to any one of claims 1 to 8, wherein the second gaseous component (126) has one or more neutral oxygen radicals (248) which are generated using a plasma-based gas generation device (246), the plasma-based gas generation device (246) comprises a plasma source (254) and a fluid-connected selection device (256) to the plasma source (254), and from a plasma generated in the plasma source (254) using the selection device (256) one or more neutral oxygen radicals (248) are extracted and supplied to the surface (118) of the photomask (100) via a supply line (258) of the plasma-based gas generation device (246) and / or via a supply line (230) fluid-connected to the selection device (256). [10] Method according to any one of claims 1 to 9, wherein the first gaseous component (316) comprises at least one etching gas component (318) for etching the defect (D1) and at least one passivation gas component (320) for passivating the surface (118) of the photomask (100) in a first passivation step (S12), and the surface (118) of the photomask (100) is passivated in step b) using the second gaseous component (126) in a second passivation step (S2). [11] Method according to any one of claims 1 to 10, wherein in step b): a third gaseous component (326) is provided at the surface (118) of the photomask (100) in the passivation area (122), the third gaseous component (326) passivates the photomask (100) in the passivation area (122) by physical adsorption, and the second and third gaseous components (126, 326) are provided simultaneously in a single passivation step or sequentially in two passivation steps (S22, S23) separated by time. [12] Method according to any one of claims 1 to 11, wherein the photomask (100) has absorber areas (A) with absorber structures (108) and reflection areas (R) that are free of the absorber structures (108), the defect (D1) has one or more of the absorber structures (108, 110) which are undesirable and which are etched in step a) using the first gaseous component (116), in step b) a fourth gaseous component (426) is provided at the surface (118) of the photomask (100), the photomask (100) in the reflection areas (R) is protected from passivation by the second gaseous component (126) by means of the fourth gaseous component (426), and The photomask (100) in the absorber regions (A) is passivated using the second gaseous component (126). [13] Device for particle beam-induced etching of a defect (D1) of a photomask (100) for microlithography, comprising: a first provisioning device (208) for providing an activating particle beam (114) at a surface (118) of the photomask (100) in a region (120) of the defect (D1), a second provision device (220) for providing a first gaseous component (116) activatable by the particle beam (114) at the surface (118) in the area (120) of the defect (D1) for etching the defect (D1), and a third provision device (222) for providing a spontaneously oxidizing oxygen-containing second gaseous component (126) at the surface (118) in a passivation area (122) of the photomask (100) encompassing the area (120) of the defect (D1) for passivating the surface (118). [14] Device according to claim 13, comprising an ozonizer (236) for generating ozone (O3) from oxygen (O2), wherein the ozonizer (236) comprises a capacitor (242) for generating an electric field (E) or a UV light source for generating UV light, and a supply line (244) for supplying the generated ozone (O3) as the second gaseous component (126') at the surface (118) of the photomask (100). [15] Device according to claim 13 or 14, comprising a plasma-based gas generation device (246) for generating the second gaseous component (126"), wherein the plasma-based gas generation device (246) comprises a plasma source (254) for generating a plasma, a selection device (256) for decoupling one or more neutral oxygen radicals (248) from the plasma, and a supply line (258) for supplying the one or more decoupled neutral oxygen radicals (248) to the surface (118) of the photomask (100).

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