Apparatus, method and computer program for processing surface of substrate

Abstract

The present invention relates to an apparatus (100), a method and a computer program comprising instructions for processing a surface (102) of a substrate (103) in a vacuum environment. The apparatus comprises: a fluid applicator (104) configured to apply a fluid (105a, 105b) to an area of the surface (102); a manipulator (106) configured to move the fluid (105a, 105b) and / or the particles affected by the fluid (105a, 105b) at least to a certain extent on the surface (102) of the substrate (103); and a positioner for relatively positioning the fluid applicator (104) and / or the manipulator (106) with respect to the surface (102).

Description

[0001] This patent application claims priority to German patent application DE 10 2023 203 816.1, entitled "Vorrichtung, Verfahren und Computerprogramm zum Bearbeiten einer Oberflächeeines Substrates", which has been filed with the German Patent and Trademark Office. That German patent application is expressly incorporated herein by reference. Technical Field

[0002] This invention relates to an apparatus and method for processing the surface of a substrate, and a corresponding computer program. More specifically, the processing includes cleaning the surface and / or purging the surface, for example, removing particles from the surface area. Background Technology

[0003] As integration density continues to increase in the microelectronics field, there is a growing need for substrates with superior surface finishes, such as photolithographic masks, mask blanks, or wafers. For example, photolithographic masks are designed to image smaller structural elements onto the photoresist layer of a wafer. The same applies to templates used in nanoimprint lithography. To meet these requirements, exposure wavelengths are becoming shorter. Currently, argon fluoride (ArF) excimer lasers are primarily used for exposure purposes, emitting at a wavelength of 193 nm. The trend is towards shorter wavelengths, extending into the extreme ultraviolet (EUV) wavelength range (10 nm to 15 nm), and towards corresponding EUV masks. For example, phase masks or phase-shifting masks, as well as masks for multiple exposures, can enable the necessary increase in resolution capacity.

[0004] As the size of structural components continues to shrink, defects frequently occur in mask production. Due to the high production costs, defective photomasks, photolithographic masks, and templates used in nanoimprint lithography are repaired as much as possible.

[0005] When repairing photomasks, portions of the absorber pattern present in locations on the mask that were not intended in the design can be removed. Alternatively, even if the mask design includes absorber pattern elements, absorber material can be deposited on locations on the mask where no absorber material is present. Both types of repair processes generate debris or particles that settle on opaque, transparent, or reflective sites on the photomask, leading to imaging defects in photolithography that are visible on the structured wafer.

[0006] Another issue is that particles from the environment may settle on the mask surface or the surface of another substrate, or on components of the optical lithography exposure system. Furthermore, the handling of the mask during its production and / or operation may generate particles that can settle on the mask.

[0007] There are two additional challenges to optical lithography exposure systems that utilize electromagnetic radiation in the EUV wavelength range. First, there is currently no satisfactory protection (e.g., pellicles) for the surfaces of EUV masks that support structural components. Therefore, EUV masks are particularly susceptible to particle deposition on these structured surfaces. Second, EUV radiation sources typically use tin plasma to generate EUV radiation (see Oscar O. Versolato, “Physics of laser-driven tin plasma sources of EUV radiation for nanolithography,” Plasma Sources Sci. Technol. 28(2019)083001, doi: 10 / 1088 / 1361-6595 / ab302). Particulates from the thermal plasma can deposit on components of the EUV exposure system, particularly on the system's optical components or elements, including the EUV mask, and may impair system functionality.

[0008] As the structural measurements of optical lithography masks continue to shrink, the cleaning process becomes increasingly difficult (see T. Shimomura and T. Liang: “50 nm particle removal from EUV mask blank using standard wet clean”, Proc. of SPIE Vol. 7488, S. 74882F-1 - 74882F-8). Furthermore, due to the decreasing exposure wavelength, increasingly smaller foreign particles or contaminants adhering to the mask surface or the optical components of the exposure system become visible on the wafer during exposure.

[0009] As structures become increasingly smaller, customized solutions are becoming more and more important for the processing and cleaning of masks and, more generally, substrates. In particular, it may be necessary to eliminate various defects on the same substrate at an acceptable level of cost and inconvenience. Surface processing, especially particle movement and lifting and / or removal of individual particles, is often a difficult and time-consuming process. External constraints can limit the available tools and processing options. Furthermore, completely removing particles adhering to the substrate surface can be expensive and inconvenient.

[0010] The prior art discloses solutions in the form of apparatus and methods for processing surfaces: these include localized spraying of surfaces in post-processing after substrate processing (US 2022 359 187 A1, US 11 062 898 B2), the use of handheld modules for the application and suction removal of cleaning liquids (US 11 392 041 B2), and electrochemical, particle beam-based methods such as localized deposition or material removal (US 7 674 706 B2).

[0011] However, these solutions have many drawbacks. Furthermore, they offer less flexibility in selecting possible processing tools and typically require separate handling steps.

[0012] Therefore, the object of the present invention is to provide an apparatus and method capable of at least partially improving the processing of a substrate surface. Summary of the Invention

[0013] This objective is achieved through the aspects described in this article.

[0014] A first aspect of the invention relates to an apparatus for processing the surface of a substrate in a vacuum environment. The apparatus includes a fluid applicator configured to apply fluid to a region of the surface. The apparatus also includes a manipulator configured to move the fluid (remove it from the region) at least to a certain extent. Alternatively or additionally, the manipulator may be configured to move fluid-affected particles (remove them from the region) at least to a certain extent on the substrate surface. Furthermore, the apparatus includes a positioner for relatively positioning the fluid applicator and / or the manipulator relative to the surface.

[0015] This apparatus enables targeted, efficient, and fluid-based processing of substrate surfaces, where fluid is understood herein to refer to liquids. Processing operations may include, for example, cleaning the substrate surface by removing particles, and may also include, for example, removing dark defects from a photomask, thus providing higher quality substrates, such as masks. Typically, the pressure and / or inaccessibility present in a vacuum environment, such as for handheld instruments, are limiting factors for substrate processing apparatuses and / or methods, particularly regarding the available tools and / or media (e.g., liquids). Furthermore, known solutions generally follow a one-stage approach to surface processing and rely on a successful first execution or simple repetition of that first attempt. This apparatus enables automated processing in a vacuum and in situ, and can also be performed in a liquid-based manner despite lower environmental pressures. Specifically, instead of simply flooding the surface with a cleaning agent as in known prior art, at least one manipulator is used to act on the area to be processed in an additional step. This processing can be achieved in a controlled and localized manner and can leverage the synergy between successive and / or at least partially parallel steps, thereby improving processing efficiency. Therefore, compared to solutions based solely on surface washing, it can specifically and effectively remove, for example, liquids and / or particles.

[0016] A vacuum environment can be generated, for example, by a single-stage or multi-stage vacuum pump within a vacuum chamber. This vacuum chamber can be, for example, the vacuum chamber of a (particle beam) microscope and / or a vacuum chamber in which the substrate and the surface to be processed are naturally present during the manufacturing process. Therefore, positioning the apparatus in a vacuum environment constitutes a time-saving, space-saving, and labor-saving option, as the substrate can be processed (e.g., cleaned) directly in situ.

[0017] A fluid applicator configured to apply fluid to a surface area can be, for example, a nozzle (e.g., made of a conductive material to avoid charging by a particle beam or due to static electricity, and / or made of a non-conductive material from which fluid can flow). Alternatively or additionally, the fluid applicator can comprise a porous material (e.g., a polymer sponge) from which fluid can flow. In any case, the fluid applicator can be adapted for localized and controlled application of fluid, for example, within a 5 mm × 5 mm or 1 mm × 1 mm area on a surface, such as on, at, and / or around particles. Thus, fluid can essentially be applied such that it is applied within the mentioned areas but not beyond them. The fluid can be applied to the surface in this area in a dropwise manner, as a (non)opaque film, and / or in any patterned form. Fluid can also be applied outside the area. In one example, a two-dimensional film can be applied to the surface, wherein the covered area covers the area but optionally also extends beyond it.

[0018] For example, a fluid can wash away particles from a substrate surface, for instance, because the fluid exerts a force on the particles by flowing around them, a force large enough to overcome the adhering interaction between the particles and the surface, causing the particles to detach from and / or loosen from the surface and be carried away / washed away by the fluid. Additionally or alternatively, the fluid can interact with the particles, for example, by splitting / breaking them into smaller components. This can include, for example, at least partial dissolution and / or dispersion of the particles and / or particle components in the fluid, thus at least partially carrying away the particles and / or particle components. In this example, the movement of the particles can occur in a stepwise manner. In all these exemplary cases, at least some of the particles are removed.

[0019] In general, all aspects related to particles described herein also relate to other contaminants, such as films, liquids, etc., and other defects and / or structures on the substrate surface (e.g., photolithographic mask structures). Fluids may include liquids, for example, liquids may be used in conjunction with particles, general applications (e.g., regarding substrate surfaces, pressure in vacuum environments, etc.), fluid applicators, and / or manipulators.

[0020] The manipulator can remove fluid and / or fluid-affected particles from a region on a substrate surface, at least to a certain extent. The use of the manipulator can be fully coordinated, for example, with the use of the fluid applicator and the selected fluid described herein, to achieve the maximum possible effect. Therefore, the device can generally be configured to perform at least two steps that may coordinate with each other: First, and as described herein, fluid can be applied to the surface using the fluid applicator to exhibit its effect on that surface, as described herein. Second, the manipulator can be used simultaneously, at least partially in parallel, and / or subsequently to move the fluid and / or one or more fluid-affected particles, at least to a certain extent, e.g., remove them from the region. This may depend on the interaction between the fluid and the particles and can be achieved in a variety of ways:

[0021] The manipulator can be configured to move particles at least to a certain extent on a surface, without the particles ultimately leaving the surface. For example, the particles can thus be moved to a site where they have only minor adverse effects (if any). Alternatively, the manipulator can completely remove the particles from the surface, for example, by means of suction, wiping, extraction, etc.

[0022] Positioners for positioning fluid applicators and / or manipulators relative to a surface may be configured to move and / or rotate fluid applicators and manipulators relative to each other and / or relative to other components specified herein, as described herein. Additionally, the device may have, for example, additional positioners that may be configured to move and / or rotate all other components specified herein, for example, relative to each other. Generally, positioning herein may refer to movement (along one or more axes, e.g., two or three axes) and / or rotation (around one or more axes, e.g., two or three axes).

[0023] In an exemplary embodiment, the positioner may be a common positioner for both the fluid applicator and the manipulator, such that the fluid applicator and the manipulator move relative to the substrate in a predetermined relative position and orientation. Alternatively or additionally, the positioner may move the substrate relative to the fluid applicator and the manipulator.

[0024] The fluid applicator and manipulator can also optionally be moved relative to each other by means of a locator. In another example, the locator moves at least two of the aforementioned components (fluid applicator, manipulator, and substrate) relative to each other. For example, the fluid applicator, manipulator, and / or substrate can be positioned in pairs relative to each other to optimize all positions.

[0025] Movement of the corresponding device via the positioner can include translational movement in space along one, two, or three axes and / or rotation about one or more axes. Generally, rotation can include free rotation or rotation limited to a certain angular range. In many instances, translation can also be spatially limited, for example, taking into account the available space within the vacuum chamber and / or the maximum deflection of the positioner.

[0026] In another possible embodiment, the fluid applicator and manipulator can move collectively relative to the substrate, and the only change with respect to the relative alignment of the fluid applicator and manipulator is the distance between them, while in this example, the relative orientation of the fluid applicator and manipulator relative to each other remains constant.

[0027] In principle, one or more (same or different) embodiments of the same components of the device may exist, such as two fluid applicators and / or two manipulators.

[0028] In exemplary embodiments, the manipulator may include a suction device, a suction device, and / or a mechanical probe: if the manipulator has a suction device, at least partial movement of, for example, fluid and / or fluid-affected particles can occur by suction of the fluid (optionally together with the affected particles). If the manipulator has a suction device, at least partial movement of, for example, fluid and / or fluid-affected particles can occur by suction of the fluid and / or fluid-affected particles by the suction device (e.g., suction into a sponge, at least temporarily attached to a suction device for lifting particles and / or fluid, etc.). In the case of a mechanical probe, the fluid and / or particles can be mechanically moved, comminuted, lifted, and / or mechanically affected and / or moved in some other way.

[0029] This enables advantageous surface treatments, such as cleaning, to specifically remove particles and / or, for example, correct imperfections in photolithographic masks. In particular, such manipulators enable the treatment of surfaces that work in conjunction with the use of fluids.

[0030] In exemplary embodiments for the mechanical separation of defects and / or particles, the fluid may be additionally or specifically used to remove broken-off material and / or shavings that may occur during the treatment of defects and / or particles. This can be performed, for example, in a second separate step after the treatment of defects and / or particles, or simultaneously. For example, the removal of particles to be removed and the resulting broken material / shavings can be performed simultaneously, thus enabling mechanical separation in an immersion manner (i.e., in the presence of fluid).

[0031] The suction device may include, for example, a nozzle for removing fluid from a surface (locally) and / or removing particles dispersed and / or dissolved in the fluid. The suction device may include, for example, a container for suctioning fluid and / or particles dispersed and / or dissolved in the fluid (the container may be, for example, attached to the suction device). Alternatively, the suction device may include, for example, a (polymer) sponge (e.g., containing or composed of polydimethylsiloxane) or another porous device suitable for suctioning fluid.

[0032] In a further example, the manipulator may include a mechanical probe. Such a probe may be, for example, an atomic force microscope probe with a tip that can be configured to make local contact with a substrate surface and / or particles on the substrate surface for analysis and / or mechanical manipulation. The probe may be configured, for example, to move particles on the surface and / or to lift particles on the surface by applying force. In exemplary embodiments, the imaging methods described herein can be used to observe this use of the probe in real time.

[0033] For example, the device may also include introducing ultrasonic and / or megasonic waves into a fluid located on the surface of a substrate.

[0034] Ultrasound and / or megasonic waves can advantageously be used, for example, to transport particles from a fluid. This use of ultrasound and / or megasonic waves can, for example, affect particles to be removed because the ultrasound and / or megasonic waves apply such great pressure to them that they break and / or break into such small components and / or agitate the particles to the point of separation from the surface and / or reduce the adhesion of the particles to the surface to the point of separation from the surface, thereby removing them in a greatly improved manner, for example, by the applied fluid.

[0035] This effect can also be accompanied by heating, which promotes, for example, dispersion, dissolution and / or separation from the surface in a fluid.

[0036] This may relate to frequencies in the range of, for example, 20 kHz to 10 MHz. A sound generator can provide this frequency and introduce it into the fluid, for example, via a mechanical probe or other suitable device, such as directly using a fluid applicator. The frequency can be correlated, for example, with the size, characteristics, composition, shape, and / or location of the particles, with the amount, characteristics, and / or properties of the applied fluid, and / or with the properties and / or characteristics of the surface.

[0037] In one instance, the fluid may be configured to at least partially move and / or at least partially absorb one or more particles on the surface.

[0038] Therefore, if surface processing requires particle movement, this fluid constitutes an advantageous choice—although this is initially difficult or even impossible to achieve, and will not damage the surface. Thus, using this fluid can improve safety and reduce failures.

[0039] Possible interactions between fluids and particles can include mechanisms such as the particles being directly dissolved in the fluid. Additionally or alternatively, particles may be partially dissolved or chemically modified and / or the interactions between particles and the surface may be altered so that they can be removed in subsequent processing steps, such as by means of manipulators, for example by subsequent use of mechanical probes and / or by further processing, such as etching (as described herein).

[0040] The fluid here can possess the following properties: it can be chemically low-reactive to particles and can remove particles primarily through mechanical aeration. It may be surface-active, thus altering the interaction between particles and surfaces. It can be directly reactive and lead to chemical and / or mechanical modification of particles. It can undergo chemical reactions in a particle beam-induced manner. In this example, the active material can be generated by a particle beam. The device can have means for providing such a particle beam (e.g., an electron beam).

[0041] The fluid may additionally or alternatively contain dissolved chemicals that are directly reactive and / or become reactive (e.g., corrosive) in a particle beam-induced manner. The exemplary properties mentioned may also occur in combination.

[0042] The effect of a fluid on particles can include the following: the application of a fluid may be accompanied by the supply of mechanical energy to overcome or reduce the binding energy between the particle and the surface. This can be controlled and / or influenced, for example, by the manner of fluid supply and / or by, for example, fluid suction removal. In a further example, the fluid may cause a reduction in the binding energy between the particle and the surface through physical and / or chemical effects. This can subsequently facilitate / make it possible, for example, to remove the particle using a suitable mechanical probe.

[0043] In exemplary embodiments, the fluid comprises an ionic liquid, preferably containing: ammonium salt, imidazole salt, morpholine salt, phosphonium salt, piperidine salt, pyridine salt, pyrrolidone salt and / or sulfonium salt.

[0044] Ionic liquids are particularly advantageous because they typically have low vapor pressures and are therefore suitable for use / able to remain liquid even at low pressures. The use of liquids at low pressures thus complements the toolset available for processing substrate surfaces in vacuum environments. While conventional methods are primarily limited to the use of gases, such as etching and deposition gases, or solids, such as mechanical probes, due to the low pressure in a vacuum chamber, liquid fluids in a vacuum environment can be used in this invention. Another advantageous aspect of ionic liquids is their inherent charge. Unlike previously known liquids, they do not require mixing with charged particles to avoid electrostatic charges.

[0045] Generally, ionic liquids may contain salts, such as cations (e.g., imidazolium, pyridinium, quaternary ammonium, and quaternary phosphonium) and anions (e.g., halogens, trifluoromethanesulfonates, tetrafluoroborates, and hexafluorophosphates). Further advantageous properties include non-flammability, non-combustibility, high thermal stability, relatively low viscosity, a wide liquid temperature range, and high electrical conductivity.

[0046] Furthermore, they may be suitable as reaction solvents: when used, the dissolved substances are dissolved only by ions, and the reaction proceeds under conditions entirely different from those using water or standard organic solvents. This unconventional reactivity opens up a variety of possible modes of use in the apparatus and / or methods described herein.

[0047] Ammonium salts may include at least one of the following salts:

[0048] • Pentyltriethylammonium bis(trifluoromethanesulfonyl)imine

[0049] • Butyltrimethylammonium bis(trifluoromethanesulfonyl)imine

[0050] • Benzyl(ethyl)dimethylammonium bis(trifluoromethanesulfonyl)imine

[0051] • Cyclohexyltrimethylammonium bis(trifluoromethanesulfonyl)imine

[0052] • Diethyl(methyl)propylammonium bis(fluorosulfonyl)imide

[0053] • Diethyl(2-methoxyethyl)methylammonium bis(fluorosulfonyl)imine

[0054] • Ethyl(2-methoxyethyl)dimethylammonium bis(fluorosulfonyl)imine

[0055] • Ethyl(2-methoxyethyl)dimethylammonium bis(trifluoromethanesulfonyl)imine

[0056] • Ethyl(3-methoxypropyl)dimethylammonium bis(trifluoromethanesulfonyl)imine

[0057] • Ethyl(dimethyl)(2-phenylethyl)ammonium bis(trifluoromethanesulfonyl)imine

[0058] • Methyltri-n-octylammonium bis(trifluoromethanesulfonyl)imine

[0059] • Tetrabutylammonium chloride

[0060] • Tetrabutylammonium iodide

[0061] • Tetrabutylammonium tetrafluoroborate

[0062] • Tetrahexylammonium iodide

[0063] • Tetrapentamonium iodide

[0064] • Tetraoctylammonium iodide

[0065] • Tetrabutylhexafluorophosphate

[0066] • Tetrahedralammonium iodide

[0067] • Tetrapentabromide

[0068] • Tetrapentylammonium chloride

[0069] • Tetrabutylammonium trifluoromethanesulfonate

[0070] • Tetrahexylammonium bromide

[0071] • Tetraheptylammonium bromide

[0072] • Tetraoctylammonium bromide

[0073] • Tetrapropylammonium chloride

[0074] • Tributylmethylammonium bis(trifluoromethanesulfonyl)imine

[0075] • Tetrabutylacetate ammonium

[0076] • Trimethylpropylammonium bis(trifluoromethanesulfonyl)imine

[0077] • Tributyl(methyl)cyanamide

[0078] • Tetrabutylammonium p-toluenesulfonate

[0079] • Tributylmethylammonium iodide

[0080] Imidazole salts may include at least one of the following salts:

[0081] • 1-Methylimidazolium hydrobromide

[0082] • 1-Methylimidazolium trifluoromethanesulfonate

[0083] • 1-Methylimidazolium bis(trifluoromethanesulfonyl)imine

[0084] • 1-Vinylimidazolium bis(trifluoromethanesulfonyl)imine

[0085] • 1-Allyl-3-methylimidazolium chloride

[0086] • 1-Allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0087] • 1-Butyl-3-methylimidazolium bromide

[0088] • 1-Butyl-3-methylimidazolium chloride

[0089] • 1-Butyl-3-methylimidazolium tetrafluoroborate

[0090] • 1-Butyl-3-methylimidazolium hexafluorophosphate

[0091] • 1-Butyl-3-methylimidazolium trifluoromethanesulfonate

[0092] • 1-Butyl-2,3-dimethylimidazolium chloride

[0093] • 1-Butyl-2,3-dimethylimidazolium hexafluorophosphate

[0094] • 1-Butyl-2,3-dimethylimidazolium tetrafluoroborate

[0095] • 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0096] • 1-Butyl-3-methylimidazolium tetrachloroferrate

[0097] • 1-Butyl-3-methylimidazolium iodide

[0098] • 1-Butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imine

[0099] • 1-Butyl-3-methylimidazolium methanesulfonate

[0100] • 1-Butyl-3-methylimidazolium trifluoro(trifluoromethyl)borate

[0101] • 1-Butyl-3-methylimidazolium tribromide

[0102] • 1-Butyl-3-methylimidazolium thiocyanate

[0103] • 1-Butyl-2,3-dimethylimidazolium trifluoromethanesulfonate

[0104] • 3,3'-(butane-1,4-diyl)bis(1-vinyl-3-imidazolium)bis(trifluoromethanesulfonyl)imine

[0105] • 1-Butyl-3-methylimidazolium dicyandiamide

[0106] • 1-Butyl-3-methylimidazolium tricyanomethane

[0107] • 1-Butyl-3-methylimidazolium trifluoroacetate

[0108] • 1-Butyl-3-methylimidazolium methyl sulfate

[0109] • 1-Butyl-3-methylimidazolium hydrogen sulfate

[0110] • 1-Butyl-3-methylimidazolium hexafluoroantimonate

[0111] • 1,3-Dimethylimidazolium dimethyl phosphate

[0112] • 1,3-Dimethylimidazolium chloride

[0113] • 1,2-Dimethyl-3-propylimidazolium iodide

[0114] • 2,3-Dimethyl-1-propylimidazolium bis(trifluoromethanesulfonyl)imine

[0115] • 1-Decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0116] • 1,3-Dimethylimidazolium iodide

[0117] • 1,3-Dimethylimidazolium methyl sulfate

[0118] • 1,3-Dimethylimidazolium bis(trifluoromethanesulfonyl)imine

[0119] • 1-Decyl-3-methylimidazolium bromide

[0120] • 1-decyl-3-methylimidazolium chloride

[0121] • 1-Decyl-3-methylimidazolium tetrafluoroborate

[0122] • 1-Dodecyl-3-methylimidazolium bromide

[0123] •1-Dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0124] • 1-Ethyl-3-methylimidazolium chloride

[0125] • 1-Ethyl-3-methylimidazolium hexafluorophosphate

[0126] • 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate

[0127] • 1-Ethyl-3-methylimidazolium tetrafluoroborate

[0128] • 1-Ethyl-3-methylimidazolium bromide

[0129] • 1-Ethyl-3-methylimidazolium iodide

[0130] • 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0131] • 1-Ethyl-3-methylimidazolium ethyl sulfate

[0132] • 1-Ethyl-3-methylimidazolium p-toluenesulfonate

[0133] • 1-Ethyl-3-methylimidazolium dicyandiamide

[0134] • 1-Ethyl-3-methylimidazolium tetrachloroferrate

[0135] • 1-Ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imine

[0136] • 1-Ethyl-3-methylimidazolium hydrogen sulfate

[0137] • 1-Ethyl-3-methylimidazolium methanesulfonate

[0138] • 1-Ethyl-3-methylimidazolium nitrate

[0139] • 1-Ethyl-3-methylimidazolium thiocyanate

[0140] • 1-Ethyl-3-methylimidazolium trifluoro(trifluoromethyl)borate

[0141] • 1-Ethyl-3-methylimidazolium acetate

[0142] • 3-Ethyl-1-vinylimidazolium bis(trifluoromethanesulfonyl)imine

[0143] • 1-Ethyl-3-methylimidazolium tricyanomethane

[0144] • 1-Ethyl-3-methylimidazolium trifluoroacetate

[0145] • 1-Ethyl-3-methylimidazolium methyl sulfate

[0146] • 1-Ethyl-3-methylimidazolium diethyl phosphate

[0147] • 1-Hexyl-3-methylimidazolium chloride

[0148] • 1-Hexyl-3-methylimidazolium hexafluorophosphate

[0149] • 1-Hexyl-3-methylimidazolium tetrafluoroborate

[0150] • 1-Hexyl-3-methylimidazolium trifluoromethanesulfonate

[0151] • 1-Hexyl-3-methylimidazolium bromide

[0152] • 1-(2-hydroxyethyl)-3-methylimidazolium chloride

[0153] • 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0154] • 1-Hexyl-2,3-dimethylimidazolium iodide

[0155] • 1-Hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine

[0156] • 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate

[0157] • 1-Hexyl-3-methylimidazolium iodide

[0158] • 1-Methyl-3-propylimidazolium iodide

[0159] • 1-Methyl-3-n-octylimidazolium bromide

[0160] • 1-Methyl-3-n-octylimidazolium chloride

[0161] • 1-Methyl-3-n-octylimidazolium hexafluorophosphate

[0162] • 1-Methyl-3-n-octylimidazolium trifluoromethanesulfonate

[0163] • 1-Methyl-3-n-octylimidazolium tetrafluoroborate

[0164] • 1-Methyl-3-propylimidazolium bromide

[0165] • 1-Methyl-3-propylimidazolium chloride

[0166] • 1-Methyl-3-propylimidazolium tetrafluoroborate

[0167] • 1-Methyl-3-pentylimidazolium bromide

[0168] • 1-Methyl-3-n-octylimidazolium bis(trifluoromethanesulfonyl)imine

[0169] • 1-Methyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imine

[0170] • 1-Methyl-3-(4-sulfobutyl)imidazolium bis(trifluoromethanesulfonyl)imide

[0171] • 1-Methyl-3-(4-sulfobutyl)imidazolium hydrogen sulfate

[0172] • 1-Benzyl-3-methylimidazolium chloride

[0173] • 1-Benzyl-3-methylimidazolium tetrafluoroborate

[0174] • 1-Berenyl-3-methylimidazolium hexafluorophosphate

[0175] Morpholine salts may include, for example, 4-ethyl-4-methylmorpholine bromide.

[0176] Phosphorus salts may include at least one of the following:

[0177] • Tributylhexylphosphine bromide

[0178] • Tributylhexadecanylphosphonium bromide

[0179] • Tributylmethylphosphonium iodide

[0180] • Tributyl-n-octylphosphine bromide

[0181] • Tetrabutylphosphonium bromide

[0182] • Tetraoctylphosphonium bromide

[0183] • Tetrabutylphosphonium tetrafluoroborate

[0184] • Tetrabutylhexafluorophosphate

[0185] • Tetrabutyl-O,O-diethyldithiophosphate

[0186] • Tributyl(2-methoxyethyl)phosphonium bis(trifluoromethanesulfonyl)imide

[0187] • Tributylmethylphosphonium bis(trifluoromethanesulfonyl)imine

[0188] • Trihexyl(tetradecyl)phosphonium dicyandiamide

[0189] • Trihexyl(tetradecyl)phosphonium chloride

[0190] • Tributyl(ethyl)phosphonium diethyl phosphate

[0191] • Tributyl(methyl)phosphonium dimethyl phosphate

[0192] Piperidine salts may include at least one of the following salts:

[0193] • 1-Butyl-1-methylpiperidinium bromide

[0194] • 1-Butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imine

[0195] • 1-Methyl-1-propylpiperidineonium bromide

[0196] • 1-Methyl-1-propylpiperidinium bis(fluorosulfonyl)imine

[0197] Pyridine salts may include at least one of the following salts:

[0198] • 1-Methylpyridinium hexafluorophosphate

[0199] • 1-Methylpyridinium bis(trifluoromethanesulfonyl)imine

[0200] • 1-Butylpyridinium chloride

[0201] • 1-Butylpyridinium bromide

[0202] • 1-Butylpyridinium hexafluorophosphate

[0203] • 1-Butyl-4-methylpyridinium bromide

[0204] • 1-Butyl-4-methylpyridinium hexafluorophosphate

[0205] • 1-Butyl-3-methylpyridinium bromide

[0206] • 1-Butylpyridinium tetrafluoroborate

[0207] • 1-Butyl-3-methylpyridinium chloride

[0208] • 1-Butyl-4-methylpyridinium chloride

[0209] • 1-Butyl-4-methylpyridinium tetrafluoroborate

[0210] • 1-Butylpyridinium bis(trifluoromethanesulfonyl)imine

[0211] • 1-Butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imine

[0212] • 1-Ethylpyridinium bromide

[0213] • 1-Ethylpyridinium chloride

[0214] • 1-Ethyl-3-methylpyridinium ethyl sulfate

[0215] • 1-Ethyl-3-(hydroxymethyl)pyridinium ethyl sulfate

[0216] • 1-Ethyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imine

[0217] • 1-Ethyl-2-methylpyridinium bromide

[0218] • 1-Ethyl-4-methylpyridinium bromide

[0219] • 1-Hexylpyridinium hexafluorophosphate

[0220] • 1-Propylpyridinium chloride

[0221] Pyrrolidone salts may include at least one of the following salts:

[0222] • 1-Allyl-1-methylpyrrolidineonium bis(trifluoromethanesulfonyl)imine

[0223] • 1-Butyl-1-methylpyrrolidineonium bis(trifluoromethanesulfonyl)imine

[0224] • 1-Butyl-1-methylpyrrolidine onium chloride

[0225] • 1-Butyl-1-methylpyrrolidineonium bromide

[0226] • 1-Butyl-1-methylpyrrolidine bis(fluorosulfonyl)imine

[0227] • 1-Butyl-1-methylpyrrolidine dicyandiamide

[0228] • 1-Butyl-1-methylpyrrolidone trifluoromethanesulfonate

[0229] • 1-Ethyl-1-methylpyrrolidineonium tetrafluoroborate

[0230] • 1-Ethyl-1-methylpyrrolidineonium bromide

[0231] • 1-Methyl-1-propylpyrrolidineonium bis(trifluoromethanesulfonyl)imine

[0232] • 1-Methyl-1-propylpyrrolidineonium bis(fluorosulfonyl)imine

[0233] • 1-(2-methoxyethyl)-1-methylpyrrolidine bis(fluorosulfonyl)imine

[0234] • 1-Butyl-1-methylpyrrolidineonium hexafluorophosphate

[0235] • 1-Methyl-1-n-octylpyrrolidineonium bis(trifluoromethanesulfonyl)imine

[0236] • 1-Methyl-1-pentylpyrrolidineonium bis(trifluoromethanesulfonyl)imine

[0237] Sulfonium salts may include at least one of the following salts:

[0238] • Trimethylsulfonium iodide

[0239] • Tributylsulfonium iodide

[0240] • Triethylsulfonylbis(trifluoromethanesulfonyl)imine

[0241] In addition to or as a substitute for ionic liquids, fluids may also include, for example, vacuum-compatible oils.

[0242] In one example, the fluid is at the operating temperature of the device, preferably at room temperature, and may have a temperature below 1.10. -6 millibars, below 1.10 -7 millibars, below 1.10 -8 millibars or less than 1.10 -9 The vapor pressure of millibars.

[0243] This low vapor pressure offers a significant advantage: the fluid remains in liquid form even at low pressures, such as when used in the vacuum chamber described herein. This means that the advantages of processing substrates under reduced pressure (e.g., avoiding harmful atmospheric gases) and the unique mechanical properties of liquids (e.g., compared to gases) can be taken advantage of, which are typically unattainable at low pressures.

[0244] The aforementioned vapor pressure enables the use of liquid fluids without failure at typical pressures in a vacuum chamber, such as in the fabrication of photomasks and / or electron microscopy.

[0245] An exemplary embodiment of the apparatus for processing a substrate surface may also include means for (local) gas supply and / or (local) gas removal. The supplied gas may be used, for example, for overall or local controlled atmosphere, such as as an etching gas or a deposition gas.

[0246] This means that the device used for supplying and / or removing gas has the following advantages:

[0247] If the gas is used to control the atmosphere (e.g., by supplying an inert gas, such as an elemental gas like nitrogen, helium, argon, neon, krypton, etc., or a gaseous molecular compound like sulfur hexafluoride), then it is not necessary to, for example, reduce the internal pressure of the vacuum chamber to a level where there is no inert gas, and no adverse effects on the substrate are expected. Instead, the inert gas creates a pristine environment for the substrate, while the relatively high pressure allows the use of various fluids, such as ionic liquids, which are liquid when the ambient pressure is higher than the vapor pressure of the corresponding fluid. This allows for controlled adjustment of the fluids, atmosphere, and pressure used according to the environment (e.g., particles to be removed, surface characteristics, etc.). In this way, the transfer of (ionic) liquids to the gas phase can be reduced; at the same time, the substrate is maintained in a (at least partially) vacuum. Generally, the vacuum described herein does not refer to a perfect vacuum, but only to an environment with a pressure reduction of about 1 bar compared to the atmospheric pressure at the Earth's surface.

[0248] If a gas is provided, for example for (particle beam-based) etching and / or deposition, this enables further advantageous options for controlled and / or localized processing of the substrate surface. For example, etching gases, such as water vapor and / or nitrosyl chloride, can be used to spontaneously etch particles in which the main component is tin. The etching gas is adsorbed at the surface, making it possible to induce localized processing, for example, simply by applying a particle beam (e.g., a focused electron beam).

[0249] For example, the deposition of a deposition gas can be used in a single step to modify the surface and / or increase the surface area of ​​particles to facilitate particle removal. Useful deposition gases include the following compounds:

[0250] • (Metal, transition element, main group) alkyl groups, such as cyclopentadienyl (Cp) or methylcyclopentadienyl (MeCp), trimethylplatinum (CpPtMe3 or MeCpPtMe3), tetramethyltin (SnMe4), trimethylgallium (GaMe3), ferrocene (Cp2Fe), diarylchromium (Ar2Cr) and other such compounds.

[0251] • Carbonyl compounds (metals, transition elements, main group elements), such as hexacarbonylchromium (Cr(CO)6), hexacarbonylmolybdenum (Mo(CO)6), hexacarbonyltungsten (W(CO)6), octacarbonyldicobalt (Co2(CO)8), and dodecacarbonyltriruthenium (Ru3(CO)). 12 ), iron pentacarbonyl (Fe(CO)5) and other such compounds.

[0252] • (Metal, transition element, main group) alkoxides, such as tetraethoxysilane (Si(OC2H5)), tetraisopropoxytitanium (Ti(OC3H7)4) and other such compounds.

[0253] • (Metal, transition element, main group) halides, such as WF6, WCl6, TiCl6, BCl3, SiCl4 and other such compounds.

[0254] • (Metal, transition element, main group) complexes, such as bis(hexafluoroacetylacetone)copper (Cu(C5F6HO2)2), trifluoroacetylacetone dimethyl gold (Me2Au(C5F3H4O2)) and other such compounds.

[0255] • Organic compounds, such as CO, CO2, aliphatic or aromatic hydrocarbons, components of vacuum pump oil, volatile organic compounds, and other such compounds.

[0256] In an exemplary embodiment, the device has been configured to generate 1.10 -9 Up to 2.10 3 millibars, 1.10 -7 Up to 1.10 2 millibars, 1.10 -6 Up to 1 millibar, or 1.10 -6 Up to 1.10 -2 A vacuum environment with an internal pressure of millibars.

[0257] For example, the internal pressure when applying liquid can be lower than 1.10. 2 millibar, less than 1 millibar or less than 1.10 -2 millibars. Alternatively or additionally, the internal pressure can be higher than 1.10. -9 Higher than 1.10 -7 or higher than 1.10 -6 .

[0258] Operating at low pressure is fundamentally advantageous because depressurization significantly reduces contamination of the substrate by particles in the atmosphere, for example. Specifically, in the context of this invention, particularly with the use of a fluid in liquid form, the internal pressure of the vacuum chamber can be appropriately regulated, especially according to the vapor pressure of the fluid, as this allows for the advantageous use of a fluid in liquid form. For example, when the fluid used and its vapor pressure are known, the pressure within the vacuum chamber can be established, for example, 105%, 110%, 115%, 120%, 130%, 140%, 150%, 200%, 300%, 400%, 500%, 1000%, 10000%, or any intermediate value or at least the mentioned value, of the fluid vapor pressure to ensure that the fluid is in liquid form.

[0259] Vacuum can be generated using pumps such as rotary vane pumps, membrane pumps, scroll pumps, turbomolecular pumps, oil diffusion pumps, ion getter pumps, titanium sublimation pumps, and / or cold traps.

[0260] In exemplary embodiments, for example, the same or different pumps may be used to operate continuously through multiple stages to obtain a final pressure. For example, a first pump (e.g., a membrane pump) may generate an initial pressure (e.g., 0.01 to 1.10). -3 (millibars). Subsequently, in the second stage, a second pump (e.g., a turbomolecular pump) can generate a high vacuum (e.g., up to 1.10 mbars). -7 (mbar). This step-by-step approach is typically necessary because a second pump can only be safely activated under a certain initial pressure. Furthermore, using additional stages, such as a third, fourth, etc., pumps can produce even lower pressures.

[0261] In an exemplary embodiment, the device may further include a particle beam source for applying a particle beam to a surface. Additionally, the exemplary device may preferably include at least one detector for particle beam-based imaging of the surface.

[0262] The particle beams described herein can typically be, for example, photon beams (e.g., in the infrared (IR), visible (VIS), ultraviolet (UV), and / or extreme ultraviolet (EUV) ranges), elementary particles (e.g., electrons, protons, and / or neutrons), atoms, ions, and / or molecules. The particle type can vary depending on the application.

[0263] In an exemplary embodiment, the particle beam may be a focused particle beam, such that when the focal plane of the particle beam is close to the substrate surface, the particle beam can be applied to, for example, a small area of ​​the surface. Focusing can be achieved using optical elements, such as lenses and / or mirrors, for example for photon beams or, for example (e.g., cylindrically symmetric and / or non-uniform) electric and / or magnetic fields, for example for electron and / or ion beams. The particle type and energy are related to the resolution limit (e.g., through its de Buglie wavelength) and can be matched to the desired resolution.

[0264] The exemplary particle beams described herein can be applied to surfaces for surface processing (e.g., particle beam-induced etching and / or deposition, as described herein) and / or for particle beam-based surface observation (e.g., scanning particle microscopy).

[0265] Additional detectors for observation can be provided: these can be, for example, IR / VIS / UV / EUV cameras / detectors, light microscopes, detectors for detecting backscattered and / or emitted particles, and / or detectors for detecting secondary electrons and / or other particles.

[0266] For example, an observation device, such as an electron beam combined with at least one electron detector in a scanning electron microscope (SEM), can be used for observation before, during, and / or after surface treatment (in this case, a cleaning operation). In one example, as described herein, the surface is observed before and / or at the start of such treatment to identify particles to be removed, and a fluid applicator and manipulator are positioned in appropriate locations near the identified particles. During treatment, the particle beam and at least one associated detector can be turned off. After processing (e.g., cleaning by removing particles), the surface is observed again to determine whether the particles have been successfully removed or whether further treatment and / or adjustments are necessary.

[0267] In another instance, the surface is continuously observed: as described herein, particles can be identified and removed by applying fluid and using manipulators while the particle beam is still applied to the surface, and the operations described herein can be observed simultaneously, where additional tools, fluid applicators, and manipulators can also be used, for example.

[0268] However, for example, the same particle beam and / or another particle beam can also be used not only for imaging, but also alternatively or additionally for other purposes, such as for deposition and / or etching. Illustrative particle beam-based etching and / or deposition operations can be performed, for example, in such a manner that particles and / or other structures are locally etched away or locally deposited by means of a focused particle beam acting locally on a fluid and / or gas. For this purpose, the particle beam and the supplied fluid and / or gas can be coupled together.

[0269] For example, the apparatus described herein can be configured to process the surface of a photomask.

[0270] Especially in the case of photolithography masks, surface processing operations, particularly cleaning operations, such as for defect removal, are necessary because any defects in the photolithography mask will be transferred to the product produced using it.

[0271] For example, the device may include a suitable holder for holding a photomask (and / or another substrate).

[0272] For example, the device described herein can also be configured to detect the position of the fluid applicator and / or manipulator.

[0273] Position detection, especially position detection relative to the surface, is advantageous for optimally positioning the fluid applicator and / or manipulator. This positioning can be crucial for the accuracy, time spent, and / or safety of surface treatment.

[0274] For example, a corresponding position can be measured by directing a particle beam onto a fluid applicator and / or manipulator. For instance, the particle beam can be directed onto and reflected from the fluid applicator and / or manipulator. If the reflected particle beam is detected by a suitable detector, that detector will detect a change in the signal of the reflected particle beam, for example, when the fluid applicator and / or manipulator reaches a point of contact with the surface (e.g., when it is moving along the surface direction via a locator). The particle beam can include, for example, an electron beam and / or an ion beam and / or a photon beam.

[0275] Alternatively or additionally, position detection may include current detection between the substrate and the fluid applicator and / or manipulator. When the fluid applicator and / or manipulator reaches the point of contact with the surface and initiates current through the contact between the surface and the fluid applicator and / or manipulator (e.g., when it is running along the surface direction via the locator), a suitable detector in this example will detect the sudden increase in current.

[0276] Two exemplary procedures for detecting the location allow for very accurate determination of the contact point with the surface, so that the fluid applicator and / or manipulator can be precisely positioned on the surface, for example, as close as possible to the defect / particle to be treated.

[0277] Alternatively or additionally, location can also be detected, for example, using distance sensors and / or microscopes and / or cameras.

[0278] For example, the apparatus described herein may also include means for X-ray spectral analysis of a surface and / or particles disposed on a surface.

[0279] X-ray spectroscopy is particularly effective at accurately identifying areas, defects, and / or particles to be treated on a surface. Based on this identification, other steps that the device can perform can be executed more accurately, quickly, and safely.

[0280] For example, X-ray spectroscopy can be energy-dispersive. Energy-dispersive X-ray spectroscopy (EDX) is based on the principle of using the X-ray radiation emitted from a region to which a particle beam is applied to determine the elemental composition of that region. Atoms in that region are excited by the particle beam and emit X-ray radiation. The wavelength of the X-ray radiation is element-specific and allows for the determination of the composition of the region being examined (e.g., particles).

[0281] For example, elemental analysis at the microscale can be performed using a combination of scanning electron microscopy and X-ray spectroscopy, known as SEM-EDX. SEM-EDX is particularly suitable for localized examinations, such as the examination of individual particles.

[0282] In a further example, such a device can be used additionally or alternatively for X-ray fluorescence analysis: X-ray excitation can lead to X-ray emission via fluorescence principles, which can be detected and used, for example, for large-area analysis.

[0283] Detection can be accomplished using, for example, a Si (Li) detector and / or a silicon drift detector.

[0284] For example, if particles are to be dissolved in a fluid, the precise match between the chosen fluid and the elemental composition of the particles is crucial for the successful execution of surface processing.

[0285] In addition, the device may include, for example, devices for Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), secondary neutral particle mass spectrometry (SNMS), Rutherford backscattering spectroscopy (RBS), and / or low-energy ion scattering spectroscopy (LEIS).

[0286] Another aspect of the present invention relates to a method for processing a substrate surface in a vacuum environment. This method may include the following steps: positioning a fluid applicator and / or manipulator relative to the surface using a positioner; applying fluid to a region of the surface using the fluid applicator; and moving the fluid and / or fluid-affected particles on the surface to at least a certain extent using the manipulator.

[0287] This method constitutes an advantageous solution where surfaces can be processed in a controlled and localized manner, which is particularly relevant considering the potential presence of small structures on the surface to be processed. For example, such localized processing operations might be necessary to remove small particles. Such particles can have diameters ranging from, for example, about 1 nm to about 100 μm. The particles can have various shapes and can interact with the substrate in any desired manner.

[0288] For example, the steps of positioning, applying, and moving can be performed in this order. However, the order can also be changed and / or the steps can be performed in parallel. For example, during the positioning of the fluid applicator and / or manipulator, fluid may have already been at least partially applied to the surface and / or moved / removed. Additionally, one or more of the additional steps described herein may be included in this or a different sequence of steps. Furthermore, for example, all the steps described herein may be repeated.

[0289] For example, in this method, the fluid applicator and / or manipulator can be positioned relative to the surface using a locator. For this purpose, a user can position the fluid applicator and / or manipulator using a control unit and, for example, via keyboard or mouse input and / or a remote control device. Simultaneously, the user can receive feedback, for example, regarding the corresponding position and alignment, via an imaging method. For a known area to be processed, the locator can also position the fluid applicator and / or manipulator accordingly in a fully or at least partially automated manner, for example, using coordinates determined for a point on the substrate to be processed (e.g., a particle). In an example of removing a particle from the surface, the appropriate end positions of the fluid applicator and manipulator are, for example, on two opposite sides of the particle, such that a fluid flow, for example, from the fluid applicator to the manipulator, can wash away the particle. For example, the fluid applicator and manipulator can therefore be positioned with an equal distance from and / or the same relative orientation as the particle, such that the fluid applicator and manipulator are mirror-configured opposite each other at the particle location on opposite sides of the particle. In other instances, the fluid applicator and manipulator can also be positioned non-uniformly / asymmetrically relative to the particle.

[0290] Applying fluid to a surface area using a fluid applicator can be done, for example, automatically or through user input (e.g., via keyboard or mouse and / or remote control). This step can occur, for example, after positioning or even at least partially during positioning. For example, the manipulator can be positioned and / or its position readjusted / corrected only after fluid application.

[0291] Fluid and / or fluid-affected particles can be at least partially removed from the area on the surface. For example, movement using a manipulator may begin (and optionally end) during fluid application, or only after fluid application. The manipulator can be configured as described herein. For example, when the manipulator includes a nozzle for suction removal of fluid (e.g., including particles dissolved in the fluid to be removed), maintaining a constant fluid flow through the area to be treated on the surface for a certain period of time may be advantageous.

[0292] The methods for processing surfaces described herein can be combined with other surface processing and / or cleaning methods that are simultaneously and / or temporarily at least partially offset.

[0293] In one instance, as another step, the method, along with the movement of fluid-affected particles, may additionally include identifying particles on the surface before and / or before relative positioning is applied.

[0294] Particle identification enables precise adjustments to all further steps based on results associated with the identified particles, such as size, location, and critical structures on the substrate near the particles that must remain intact. This improves the efficiency, safety, and speed of the method.

[0295] This identification can be related not only to particles, but also to other structures, such as (erroneously applied) parts of the structure of a photomask, other impurities, etc.

[0296] The method may also include, for example, introducing ultrasonic and / or megasonic waves into a fluid present on the surface of the substrate.

[0297] This use of ultrasound and / or megasonic waves can provide the advantages described herein, such as simplifying the removal of particles to be removed.

[0298] In one instance, the method may also include mechanically manipulating the identified particles with a manipulator.

[0299] In addition to applying fluid, mechanical action can be advantageously used to move particles, for example when fluid action alone cannot trigger any movement.

[0300] The manipulators here may include, for example, mechanical probes capable of acting on particles, such as to move or lift / remove particles from a surface. The probes may be, for example, atomic force microscope probes and may also be used in atomic force microscopy. Such probes may be configured to contact the particles to be removed, causing the particles to adhere to the probe tip, and to lift and thus remove the adhered particles from the surface.

[0301] For example, the method may also include influencing the particles through fluids, preferably by dissolving, dispersing, and / or altering the particle surface.

[0302] This effect of the particles is advantageously synergistic with, for example, the mechanical effects of the particles and / or the use of manipulators for pumping fluid away along with the particles, because these steps can more easily move and / or remove the affected particles, as described herein.

[0303] Dissolution, dispersion, and / or alteration of the particle surface can be performed as described herein.

[0304] This method may also include, for example, generating a controlled atmosphere within a vacuum chamber.

[0305] This step brings the advantages described in this paper, namely fewer soil particles in the atmosphere of the vacuum chamber, lower surface exposure, and compatibility with the planned method.

[0306] As described in this article, atmosphere control can include supplying the appropriate gas and establishing the desired pressure.

[0307] Alternatively, the method may include matching the internal pressure within the vacuum chamber with the fluid.

[0308] In particular, precise matching of the fluid vapor pressure with the fluid used is advantageous, as it eliminates significant limitations in the selection of pressure ranges or fluids. This provides high flexibility in surface processing and improves the efficiency and safety of the method.

[0309] For example, the atmosphere can be changed once or multiple times during the method to ensure that ideal conditions exist for each step.

[0310] Additionally, the method may include supplying gas.

[0311] As described herein, this can include, for example, inert gases, deposition gases, and / or etching gases, and provides the advantages described herein.

[0312] For example, the method may include, for instance, locally supplying deposition gas to the area. This reduces the accuracy of the method and the consumption of the gas used. Generally, such supply can supplement the deposition methods described herein, for example, for moving and / or fixing particles.

[0313] Localized supply of gases (such as etching or deposition gases) allows the gas to locally exhibit its effects, such as depositing materials or etching elements. These steps can further be induced by locally applied particle beams, such as focused electron beams that can also be provided by the device.

[0314] The method may also include applying a particle beam to the surface and preferably observing the surface by particle beam-based imaging.

[0315] The use of particle beams, for example for the purposes described herein, can advantageously act on surfaces, particles and / or structures present on surfaces, fluids, gases, etc., and facilitate further steps, thus improving the efficiency of the method. Additionally or alternatively, it can enable particle beam-based imaging, thus constituting an important safety mechanism.

[0316] During this method, a uniform particle beam can be used, for example, for observing a surface, or it can be turned on and off once or multiple times, and / or different particle beams with different parameters and / or particles can be used in different and / or at least partially overlapping time periods. Generally, this method may include assessing / estimating the particle dose required for observation (e.g., the electron dose in an electron beam example of an electron microscope). Such estimation may include recording the dose already applied and / or the dose to be applied. For example, this dose may be expressed relative to a dose threshold at which, for example, damage to the substrate surface, material deposition from the deposition gas, etc., is expected.

[0317] Additionally, the method may include directing a particle beam onto a region for particle beam-induced deposition, preferably to expand the surface area of ​​the identified particles.

[0318] This can affect particles, especially their surfaces, so that subsequent steps, such as the movement of particles through fluids and / or manipulators, are facilitated and simplified.

[0319] Electron beams can be focused to tiny focal points with diameters of a few nanometers or even < 1 nm. The advantage of electron beam-induced deposition (EBD) is that it allows for precise localization of the deposition reaction. Furthermore, the electron beam in EBD processes generally does not damage the substrate, such as photomasks containing troublesome particles.

[0320] For example, particle beam-induced deposition can be performed by depositing material onto the surface of particles, for example, to move the particles. This can be achieved using the deposition gas described herein. Alternatively, it is conceivable that deposition can be achieved using a particle beam and a fluid. Deposition can proceed until the particles reach their target size and the size of the attack zone has increased, allowing the particles to be moved, for example, by using a fluid.

[0321] In another instance, particle beam-induced deposition can be used to immobilize particles, as described in this paper.

[0322] This method may also include detecting the position of the fluid applicator and / or manipulator. This can preferably be achieved by directing the particle beam onto the fluid applicator and / or manipulator and / or detecting the current flow between the substrate and the fluid applicator and / or manipulator.

[0323] These methods and steps bring about the aforementioned advantages, especially the precise determination of the contact points with the surface and the related improvement in the accuracy and precision of the method.

[0324] These methodological steps can occur, for example, only during positioning and / or continuously / repeatedly during processing, so that the position can be observed throughout the processing duration and that potentially unwanted positional changes can be avoided and / or quickly corrected.

[0325] The method may also include, for example, analyzing the identified particles by X-ray spectroscopy, and preferably matching further steps based at least in part on the analysis.

[0326] This improves the planarability of the method's steps, and thus increases its efficiency and reduces the time spent. Furthermore, it reduces unsuccessful surface finishing attempts.

[0327] X-ray spectroscopy, especially EDX, can provide conclusions about the elemental composition of the area to be processed on the substrate surface.

[0328] In one example, in the first step, particles can be identified using an electron microscope. In subsequent steps, the particle composition can be determined using EDX. Based on the information obtained (e.g., particle composition, size, location, number, surface properties, grain size, etc.), subsequent steps can be planned. For example, appropriate fluids, appropriate internal pressures, appropriate atmospheric gases, appropriate etching gases, appropriate manipulators, etc., can be used as described herein.

[0329] The method may also include, for example, fixing the identified particles at appropriate locations on the surface.

[0330] This constitutes a suitable solution when particles cannot be completely removed from the surface.

[0331] For example, when particles cannot be completely removed from the surface but are located at and / or have moved to a non-problematic site, it may be helpful to anchor the particles there. Particle beam-induced deposition—as described herein—can, for example, ensheath the particles there, depositing material on and around the particles, and anchoring the material to the surface.

[0332] Another aspect of the invention relates to a computer program that includes instructions for performing the method steps described herein.

[0333] Such computer programs can at least partially automate the steps of a corresponding method. Specifically, automating error-prone steps and / or steps that require large amounts of data can avoid errors, minimize the time spent, improve accuracy, and / or optimize method planning.

[0334] For example, the computer program can be executed by a computer connected to the corresponding device. Alternatively or additionally, the computer program can be executed at least partially by a corresponding control unit, as described herein, which enables the user to control the corresponding device at least partially.

[0335] Furthermore, there are possible embodiments in which the computer program plays an auxiliary role, such that the various steps of the method are influenced by instructions from the user and the computer program in a partially automated manner. For example, the computer program can be instructed to perform individual steps or a series of steps based on user instructions.

[0336] Generally, all the functions described herein related to the apparatus and / or parts thereof can also be implemented as steps of a method or instructions of a computer program, and vice versa. Similarly, all steps of a method can be translated into instructions in a computer program, and vice versa. Attached Figure Description

[0337] The preferred exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0338] Figure 1 A side view of the device according to the invention is shown;

[0339] Figure 2 A schematic side view of a manipulator in the form of a suction device according to the present invention is shown, wherein the suction device comprises a polymer sponge;

[0340] Figure 3 A schematic side view of a device according to the invention is shown, which has a manipulator in the form of a suction device;

[0341] Figure 4 A schematic side view of a device according to the invention is shown, which has a manipulator in the form of a mechanical probe;

[0342] Figure 5 A schematic side view of the apparatus according to the invention in fluid and particle beam-based deposition and / or etching is shown; and

[0343] Figure 6 A schematic side view of the apparatus according to the invention in gas and particle beam-based deposition and / or etching is shown. Detailed Implementation

[0344] The present preferred embodiments of the apparatus and method of the present invention for removing at least a single particle from a substrate are described in more detail below. Processing examples in the form of particle removal are used to describe the apparatus and method according to the present invention. However, these are not limited to the examples described below. Rather, they can be used to process or remove any type of particle, structure, material, etc.

[0345] Figure 1 An apparatus 100 for processing the surface 102 of a substrate 103 is shown.

[0346] The device has a fluid applicator 104, which, in the illustrated exemplary embodiment, is designed as a nozzle for applying a fluid 105a (e.g., the ionic liquid described herein). The fluid applicator 104 is aligned at an angle relative to the surface 102, and the nozzle opening is positioned close to the surface 102 and to the left of the particle 101. The nozzle is aligned such that the fluid 105a flows in the direction of the particle 101 and / or is compressed and impacts the left side of the particle 101 upon exiting the nozzle. The direction of the arrow representing the fluid 105a indicates the flow direction of the fluid 105a. When the fluid applicator 104 and / or manipulator 106 includes a nozzle, its nozzle opening may have, for example, an approximately circular shape and may have, for example, the following diameters: less than 1 μm (e.g., in the form of a nano-nozzle and / or nano-droplet), less than 10 μm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, less than 2 mm (or even larger), or any intermediate value. In other instances, the nozzle opening may have, for example, comparable dimensions and / or different opening shapes, such as elongated, elliptical, rectangular, or irregular shapes, for example, having comparable dimensions related to the circular nozzle opening described herein.

[0347] The exemplary particle 101 has an irregular shape and a size roughly equivalent to that of the nozzle opening. The size of the particle 101 is not proportional, and it can be much larger or much smaller. The fluid 105a can interact with the particle 101 in one of the ways described herein, for example, it is swept away by the fluid 105b and the particle 101 is moved by the fluid 105b.

[0348] The device 100 further includes a manipulator 106. In the embodiment shown in illustrative form, fluid 105b is drawn away by the manipulator 106. Figure 1 The exemplary manipulator 106 is designed as a suction device with a nozzle for removing fluid 105b along with particles 101 by suction. Manipulator 106 in Figure 1The manipulator 106 is aligned, like the fluid applicator 104, at an angle relative to the surface 102 of the substrate 103. The nozzle opening of the manipulator 106 is directed toward the right of the particle 101, such that the flow direction of the fluid 105b directs the fluid 105b toward the nozzle opening of the manipulator 106. The manipulator 106 can be positioned, for example, closer to the surface 102 than the fluid applicator 104. The closer positioning of the manipulator 106 to the surface 102 facilitates the removal of the fluid 105b by suction. Like the fluid applicator 104, the manipulator 106 can also contact or be further removed from the surface 102. The angles at which the manipulator 106 and the fluid applicator 104 are aligned with respect to the surface 102 are slightly different. However, they may also be, for example, the same or significantly different.

[0349] The manipulator 106 and fluid applicator 104 of the illustrated device 100 are positioned and aligned at an angle of approximately 180° to each other (i.e., relative to each other) in the plane of surface 102, and are located on different sides of particle 101. As described herein, this angle can be varied in the following ways:

[0350] The fluid applicator 104 and the manipulator 106 can have different configurations. For example, when both the fluid applicator 104 and the manipulator 106 have nozzles—one of the fluid applicators 104 is used to apply fluid 105a, and the manipulator 106 is used to remove fluid 105b by suction—they can be opposite each other such that the openings of the two nozzles are aligned facing each other, i.e., at a first 180° angle in a first plane (e.g., a plane parallel to the surface 102 of the substrate 103). In other exemplary embodiments, the nozzle openings can be rotated arbitrarily relative to each other, for example, by a first angle in the first plane of 175°, 170°, 165°, 160°, 155°, 150°, 145°, 140°, 135°, 130°, 125°, 120°, 115°, 110°, 105°, 100°, 95°, 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15°, 10°, 5°, or any other value between 0° and 180°. For example, the nozzles can also be aligned parallel to each other, i.e., aligned at a first angle of 0° in the first plane, such that the openings point in the same direction.

[0351] The nozzle may also be rotated away from the first plane (e.g., the plane of the surface) in the same or different ways, for example, tilted at an angle or acute angle relative to the surface. This second angle may be, for example, 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, or an intermediate value.

[0352] When the fluid applicator 104 and / or the manipulator 106 does not have any nozzles, such as Figure 1 As in the example, different exemplary configurations can also be implemented additionally.

[0353] The device 100 additionally includes a particle beam source 107 for emitting a particle beam 108. The particle beam 108 is applied to the surface 102, and more specifically, to the region of the particles 101. Typically, the particle beam 108 is focused such that it can be applied locally, for example, within a range comparable to and / or smaller than the size of the particles 101. The particle beam source 107 can provide particles, such as electrons, for example, with an accelerating voltage of 0.01 kV to 30 kV, which enables sub-nanometre focusing. Typical currents for the particle beam (e.g., an electron beam) can be, for example, in the following ranges: 0 to 300 nA, 3 pA to 20 nA, 100 pA to 300 nA, 1 nA to 300 nA, or 1 pA to 100 nA.

[0354] The device 100 also has a mechanical probe 109. Figure 1 The mechanical probe 109 is in the form of an atomic force microscope tip and is configured to mechanically act on particle 101 and / or be used for atomic force microscopy. The probe 109 can be moved and / or detected with an accuracy of about 50 pm (e.g., in the range of 10-100 pm).

[0355] Additionally, the device 100 includes a local gas supply device 110, which can be configured to supply, for example, an inert gas to provide an atmosphere and / or an etching gas. The gas supply device 110 is configured as a nozzle within the device 100, which, like other components of the device 100, can be positioned and aligned / rotated relative to the substrate 103. Specifically, a gas that affects particles 101, for example, through particle beam-based deposition, can therefore be supplied locally, i.e., in the vicinity of particles 101. The nozzle can be a single nozzle serving as a gas supply device for at least one type of gas, which is supplied continuously or simultaneously. Alternatively, a group of nozzles may be present, such as one, two, three, or more nozzles, wherein in each case one nozzle serves as a gas supply device for the corresponding type of gas.

[0356] The device 100 also includes an optical microscope 111. Alternatively or additionally, the device 100 may also include at least one detector for particle beam imaging.

[0357] The following diagram, Figures 2 to 4 Three different embodiments of the manipulator are shown: suction device ( Figure 2 ), suction device ( Figure 3 ) and mechanical probes ( Figure 4 The features described below can generally be applied to the manipulator according to the invention, regardless of the specific embodiment of the corresponding figure (suction device, suction device, or mechanical probe):

[0358] Figure 2 A schematic side view of a device 200 according to the invention is shown, which has a manipulator in the form of a suction device, wherein the suction device comprises a polymer sponge 206.

[0359] Figure 2 A schematic side view of a manipulator in the form of a polymer sponge 206 is shown in detail, which draws in / draws in fluid 205, such as an ionic liquid, applied to a surface 202. The manipulator can be moved relative to the surface 202, for example by means of a corresponding positioner. Pure fluid 205, or fluid with dispersed and / or dissolved particles (not shown), can be absorbed by the polymer sponge 206. Gray arrows indicate the direction of fluid flow.

[0360] Figure 2 The fluid 205 is specifically applied to the site on the surface 202 by the fluid applicator 204.

[0361] The polymer sponge 206 has a rectangular cross-section, but in other possible embodiments it may have other shapes, such as an irregular quadrilateral or a more complex cross-section. This shape can particularly mate with surface 202.

[0362] The manipulator / polymer sponge 206 is tilted at an acute angle relative to the surface 202 and positioned close to the surface 202 without contacting it, but it can also be positioned closer to the surface 202 such that the manipulator / polymer sponge 206 contacts the surface 202, and / or tilted at a different angle relative to the surface 202.

[0363] The polymer sponge 206 is positioned sufficiently close to surface 202 to bring it into contact with the fluid 205. Due to the adhesion force between the polymer sponge 206 and the fluid 205, the polymer sponge 206 can absorb the fluid 205, as schematically indicated by the arrow. If the polymer sponge 206 has already at least partially absorbed the fluid 205, the cohesive force acts additionally on the fluid 205 and further aids in absorption.

[0364] Figure 3 A schematic side view of a device 300 according to the invention is shown, which has a manipulator in the form of a fluid applicator 304 and a suction device 306. Fluid 305 is specifically applied to a site on surface 302 via the fluid applicator 304. Figure 3 The suction of the suction device 306 specifically influences and / or controls parameters such as the flow direction, flow rate, flow profile, fluid film thickness, and / or other parameters of the fluid flow from the fluid applicator 304 to the suction device 306, in order to suck in the fluid 305, such as an ionic liquid, applied to the surface 302. Gray arrows indicate the direction of fluid flow. For example, the force generated by the liquid flow can be used to at least partially move and / or flush away one or more particles affected by the fluid 305. In particular, the adhesion between the nozzle and the fluid volume of the suction device 306 can affect the aforementioned flow characteristics.

[0365] The manipulator 306 can be moved relative to the surface 302, for example by means of a corresponding locator. Pure fluid 305 or fluid together with dispersed and / or dissolved particles (not shown) can be drawn in by the suction device 306. For this purpose, the nozzle opening of the suction device can, for example, have the same or larger size as the particles to be removed in their original shape and / or shape affected by the fluid 305.

[0366] Figure 4 A schematic side view of a device 400 according to the invention is shown, which has a manipulator in the form of a fluid applicator 404 and a mechanical probe 406.

[0367] Figure 4 The fluid applicator 404 applies a fluid (e.g., an ionic liquid) to the sites on the surface 402 where particles 401 are present, so that the particles 401 affected by the fluid 405 can be moved by means of a mechanical probe 406 and / or the fluid 405 can be moved at least to some extent (as indicated by the right-hand arrow) on the substrate surface 402. Figure 4 Examples of these have tips that are essentially supported at right angles, such as AFM tips.

[0368] Figure 5 A schematic side view of an apparatus 500 according to the invention is shown in fluid and particle beam-based deposition and / or etching. The apparatus 500 includes a fluid applicator 504, a fluid manipulator 506, and a particle beam source 507, which is configured, as described herein, to guide a particle beam 508 onto a surface 502, and... Figure 5The particle beam 508 is guided to the particles 501 on the surface 502. The fluid applicator 504 applies a fluid 505 (e.g., an ionic liquid) to the sites on the surface 502 where the particles 501 are located, so as to influence the particles 501 through the fluid 505. Specifically, in... Figure 5 In this process, the particle surface 501a of particle 501 is affected because material is deposited there from fluid 505 in a particle beam-induced manner, and / or because the interaction between the fluid and the particle beam at least partially etches and / or abrades the particle surface 501a in some other way. This enables / simplifies any subsequent suction removal performed by manipulator 506.

[0369] exist Figure 5 During deposition and / or etching, the manipulator 506 is spaced apart from the site of the particle 501 by a locator (not shown) to enable uninterrupted deposition and / or etching. The fluid applicator 504 and / or other components of the device 500 (possibly not shown) may also be appropriately positioned.

[0370] Figure 6 A schematic side view of an apparatus 600 according to the invention is shown in gas and particle beam-based deposition and / or etching. The apparatus 600 includes a fluid applicator 604, a fluid manipulator 606, a particle beam source 607, and a (local) gas supply device 610. The particle beam source 607 is configured, as described herein, to guide a particle beam 608 onto a surface 602, and... Figure 6 The gas is guided to the particles 601 on surface 602. Gas supply device 610 provides gas 610a near the surface 602 where particles 601 are present, so as to influence the particles 601 via gas 605. More specifically, in... Figure 5 In this process, the particle surface 601a of particle 601 is affected because material is deposited there from gas 610a in a particle beam-induced manner and / or because the interaction between gas 610a and the particle beam at least partially etches and / or erodes / grinds the particle surface 601a in some other way. This can enable / simplify subsequent suction removal by manipulator 606, and for example by the additional use of fluid.

Claims

1. An apparatus (100) for processing the surface (102) of a substrate (103) in a vacuum environment, wherein the apparatus (100) comprises: A fluid applicator (104) is configured to apply fluid (105a, 105b) to the area of ​​the surface (102); The manipulator (106) is configured to move the fluid (105a, 105b) and / or the particles affected by the fluid (105a, 105b) on the surface (102) of the substrate (103) to at least a certain extent. as well as Positioner for relative positioning of the fluid applicator (104) and / or the manipulator (106) relative to the surface (102).

2. The apparatus (100) of claim 1, wherein the manipulator (106) includes a suction device, a suction device and / or a mechanical probe.

3. The apparatus (100) of claim 1 or 2 further includes means for introducing ultrasonic and / or megasonic waves into the fluid located on the surface (102).

4. The apparatus (100) according to any one of claims 1-3, wherein the fluid (105a, 105b) is configured to at least partially move and / or at least partially absorb one or more particles (101) on the surface (102).

5. The apparatus (100) of any one of claims 1-4, wherein the fluid (105a, 105b) comprises an ionic liquid, which preferably contains: an ammonium salt, an imidazole salt, a morpholine salt, a phosphonium salt, a piperidine salt, a pyridine salt, a pyrrolidone salt, and / or a sulfonium salt.

6. The apparatus (100) according to any one of claims 1-5, wherein the fluid (105a, 105b) is at its operating temperature, preferably at room temperature, and has a vapor pressure of less than 1.

10. -6 millibars, below 1.10 -7 millibars, below 1.10 -8 millibars or less than 1.10 -9 millibar.

7. The apparatus (100) of any one of claims 1-6 further includes means (110) for gas supply and / or gas removal.

8. The apparatus (100) as claimed in any one of claims 1-7, wherein the apparatus (100) has a vacuum environment configured to generate 1.10 -9 Up to 2.10 3 millibars, 1.10 -7 Up to 1.10 2 millibars, 1.10 -6 Up to 1 millibar, or 1.10 -6 Up to 1.10 -2 The internal pressure of millibars.

9. The apparatus (100) of any one of claims 1-8 further includes a particle beam source (107) for applying a particle beam (108) to the surface (102), and preferably includes at least one detector for particle beam imaging of the surface (102).

10. The apparatus (100) according to any one of claims 1-9, wherein the apparatus (100) is configured to process the surface (102) of a photomask.

11. The apparatus (100) as claimed in any one of claims 1-10, further configured to detect the position of the fluid applicator (104) and / or the manipulator (106), preferably by means of: The particle beam is directed to the fluid applicator (104) and / or the manipulator (106); and / or The flow of current between the substrate (103) and the fluid applicator (104) and / or the manipulator (106) is detected.

12. The apparatus (100) according to any one of claims 1-11 further includes means for performing X-ray spectral analysis on the surface (102) and / or particles (101) disposed on the surface.

13. A method for processing the surface (102) of a substrate (103) in a vacuum environment, comprising the following steps: Position the fluid applicator (104) and / or manipulator (106) relative to the surface (102) using a positioner; The fluid is applied to the area of ​​the surface (102) by the fluid applicator (104); and The manipulator (106) moves the fluid and / or the particles (101) affected by the fluid (105a, 105b) on the surface (102) to at least a certain extent.

14. The method of claim 13, wherein the processing includes moving the particle (101) affected by the fluid (105a, 105b), and wherein the method further includes the step of: Before the relative positioning and / or before the application, identify the particle (101) on the surface (102).

15. The method of claim 13 or 14, further comprising introducing ultrasonic and / or megasonic waves into the fluid (105a, 105b) present on the surface (102).

16. The method of any one of claims 13-15, further comprising mechanically manipulating the identified particle (101) by means of the manipulator (106).

17. The method of any one of claims 13-16, further comprising influencing the particle (101) by the fluid, preferably by dissolving, dispersing and / or altering the particle surface.

18. The method of any one of claims 13-17, further comprising generating a controlled atmosphere within a vacuum chamber.

19. The method of claim 18, further comprising matching the internal pressure of the vacuum chamber with the fluid (105a, 105b).

20. The method of any one of claims 13-19, further comprising supplying gas.

21. The method of any one of claims 13-20 further includes applying a particle beam (108) to the surface (102) and preferably observing the surface (102) by particle beam-based imaging.

22. The method of claim 21, further comprising directing the particle beam (108) onto a region for particle beam-induced deposition, preferably for expanding the surface of the identified particles (101).

23. The method of any one of claims 13-22, further comprising detecting the position of the fluid applicator (104) and / or the manipulator (106), preferably by means of: The particle beam is directed onto the fluid applicator (104) and / or the manipulator (106); and / or The flow of current between the substrate (103) and the fluid applicator (104) and / or the manipulator (106) is detected.

24. The method of any one of claims 13-23, further comprising analyzing particles (101) on the surface by X-ray spectroscopy, and preferably adjusting further method steps based at least in part on the analysis.

25. The method of any one of claims 13-24, further comprising fixing the identified particle (101) at an appropriate position on the surface (102).

26. A computer program comprising instructions for performing the steps of the method as claimed in any one of claims 13-25.

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