Apparatus and method for analyzing and / or processing sample with particle beam

Abstract

To provide an improved apparatus for analyzing and / or processing samples with particle beams.SOLUTION: An apparatus (100) disclosed herein that analyzes and / or processes a sample with a particle beam (112) includes a sample stage (120) that holds the sample, and a supply unit (110) that supplies the particle beam. The supply unit has an opening (114) that guides the particle beam to a processing position on the sample, and a shielding element (116) that shields an electric field (E) generated by an electric charge (Q) accumulated on the sample, the shielding element covers the opening, embodied in a sheet-like manner, and includes a conductive material, the shielding element has a convex section (117) that is convex with respect to the sample stage, the convex section has a through opening (118) for the particle beam to pass through to the sample.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for analyzing and / or processing a sample with a particle beam, and to a corresponding method.

[0002] The content of the priority application German Patent Application No. 102020124306.5 is incorporated by reference in its entirety. [Background technology]

[0003] Microlithography is used to manufacture finely structured components, such as integrated circuits. Microlithography processes are carried out using a lithography apparatus having an illumination system and a projection system. An image of a mask (reticle) illuminated by the illumination system is then projected by the projection system onto a substrate, for example a silicon wafer, that is coated with a photosensitive layer (photoresist) and positioned in the image plane of the projection system in order to transfer the mask structure into the photosensitive coating of the substrate.

[0004] In this case, the mask, otherwise the lithography mask, is used for multiple exposures, and therefore it is very important that said mask is free of defects. Therefore, a correspondingly large effort is made to inspect lithography masks for defects and to repair identified defects. The size of defects in lithography masks can be on the order of a few nanometers. In order to repair such defects, a device is required that provides a very high spatial resolution for the repair process.

[0005] Suitable devices for this purpose are those which activate local etching or deposition processes based on particle beam induced processes.

[0006] EP 1587128 discloses one such device, which uses a beam of altered particles, particularly an electron beam in an electron microscope, to initiate a chemical reaction process. If the sample is non-conductive or has only a slight dielectric property, the use of charged particles can cause the sample to become charged. This can lead to uncontrolled beam deflection, which limits the achievable process resolution. It is therefore proposed to place a shielding element very close to the processing location so that sample charging is minimized and process resolution and process control are improved.

[0007] For the desired repair process, a process gas must be transported to the treatment location. Typical process gases may already be highly reactive in their ground state, and furthermore, highly reactive atoms or molecules may be generated during the treatment process, which may, for example, damage and / or deposit on the surfaces of components of the particle beam device. This may result in shorter service intervals for the respective particle beam device and / or process instabilities.

[0008] The achievable processing speed in such particle beam-induced processes depends, inter alia, on the process gas pressure at the processing location. To achieve a high processing speed, a high process gas pressure at the processing location is desirable. This can be achieved, for example, by feeding the process gas through the particle beam exit opening, in which case the process gas can then flow unimpeded into the particle beam device. On the other hand, in terms of the lifespan of the components used, it is desirable to aim to minimize the gas flow of the process gas from the processing location into the particle beam device.

[0009] DE 10208043 A1 discloses a material processing system that can be used in methods for material processing by material deposition from gases, such as CVD (chemical vapor deposition), or for material removal by means of a delivered reactive gas, where, inter alia, the gas reaction resulting in material deposition or material removal is initiated by an energy beam directed at a region of the workpiece to be processed. Summary of the Invention

[0010] Against this background, it is an object of the present invention to provide an improved apparatus for analyzing and / or processing samples with particle beams.

[0011] According to a first aspect, an apparatus for analyzing and / or processing a sample with a particle beam is proposed. The apparatus comprises a sample stage for holding the sample and a supply unit for supplying the particle beam. The supply unit comprises an opening for guiding the particle beam to a processing position on the sample and a shielding element for shielding an electric field generated by electric charges accumulated on the sample. The shielding element covers the opening, is embodied in a sheet-like manner, and comprises an electrically conductive material. Furthermore, the shielding element comprises a convex section, which is convex with respect to the sample stage and has a through opening for the particle beam to pass through to the sample.

[0012] This device has the advantage that the electric field formed between the shield element and the sample due to charging of the sample or its surface is less likely to affect the particle beam in an uncontrolled manner. The convex section of the shield element allows the distance between the shield element and the surface of the sample in the region of the processing position to be kept very small without the need to keep the entire shield element at a very small distance, which reduces the complexity of positioning the sample relative to the shield element. It can also be said that there is more room between the sample and the supply unit for tilting.

[0013] The apparatus comprises a sample stage for holding a sample. Preferably, the sample stage is arranged in the vacuum housing. The sample stage preferably has a positioning unit for positioning the sample stage relative to the supply unit. The positioning unit may, for example, be configured to displace the sample stage along three spatial axes. Furthermore, the positioning unit may be configured to rotate the sample stage about at least one of said axes, preferably about at least two of said axes. The sample stage is preferably held by a holding structure in a vibration-decoupled and / or actively vibration-damped manner.

[0014] The particle beam comprises charged particles, such as ions, electrons, or positrons. Accordingly, the supply unit has, for example, a beam generating unit with an ion source or an electron source. The particle beam, consisting of charged particles, can be influenced, i.e., accelerated, directed, shaped, and / or focused, by electric and magnetic fields. For this purpose, the supply unit may have several elements configured to generate corresponding electric and / or magnetic fields. These elements are particularly arranged between the beam generating unit and the shielding element. The particle beam is preferably focused onto the processing location. This is understood to mean, for example, that the particle beam has a predetermined diameter, in particular a minimum diameter, when it strikes the processing location. The supply unit preferably comprises a dedicated housing in which the aforementioned elements are arranged, which preferably has a thickness of, for example, 10 mm. -7 ~10 -8 It is embodied as a vacuum housing, which is maintained at a residual gas pressure of 1000 mbar.

[0015] The shield element is arranged over an opening in the supply unit through which the particle beam is guided to a processing position on the sample, so that the shield element forms the component of the supply unit closest to the sample stage in the beam direction.

[0016] The device is, for example, a scanning electron microscope. To achieve high resolution, the electron beam must be controlled very precisely, especially with regard to the electron energy, the beam diameter when it strikes the sample (hereafter referred to as the focus), and the temporal stability of the impact point. In particular, in the case of samples with sections made of non-conductive or only slightly conductive material, the incident charged particles result in the accumulation of charges on the sample, which creates an electric field. The particles of the particle beam, as well as, for example, secondary and backscattered electrons that are detected to generate an image, are also affected by the electric field, which can result in, for example, a loss of resolution.

[0017] The shielding element performs the task of shielding the electric field of the charges, in other words spatially confining the electric field, in particular to the smallest possible gap between the shielding element and the sample. For this purpose, the shielding element comprises a conductive material. For example, the shielding element is grounded so that charges impinging on the shielding element dissipate.

[0018] The shielding element itself is embodied in a sheet-like manner, which sheet forms a three-dimensional shape with a convex section on its surface, which section is convex relative to the sample stage, and the convex section preferably forms the section closest to the sample stage, i.e. the distance between the sample stage or sample and the shielding element is smallest in the area of ​​the convex section.

[0019] The surface of the shield element, particularly in the convex section, has a convex area formed thereon.

[0020] In this case, "convex" is understood to mean that the cutting edge of a cross section through the shield element extending through the convex section has a convex path within the convex section according to the mathematical definition of this term, said definition being as follows: Function f:C→R, where C is R n A convex subset of C satisfies the following formula (1): f(a·x+(1-a)·y)≦a·f(x)+(1-a)·f(y) Equation (1) is said to be convex if

[0021] In formula (1), R n represents the n-dimensional vector space for real numbers. For shield elements, n=2, that is, R n =R 2 where C is the projection of the shield element onto the sample stage and f describes the height of the shield element above the sample stage.

[0022] If the relationship between the left and right sides of equation (1) does not include the case "equal to", i.e., a true "less than" is required and the cases where x=y and a=0 or a=1 are excluded, then in technical terms this is also referred to as strictly convex. The convex section of the shielding element is preferably embodied so that a cutting edge of the shielding element extending through the convex section has a path that is strictly convex in this sense. An example of an area having this shape is a sphere or a section of a sphere. Furthermore, a strictly convex function will generate a corresponding area when a body of revolution is formed based on this function, for example, a paraboloid of revolution by rotation of a parabola.

[0023] The shield element has a through-opening in the convex section, through which the particle beam passes and impinges on the sample. In the spatial region above the shield element, where the particle beam originates, the shield element effectively shields the electric field of the charge disposed on the sample. It should be noted that the shield element may have further through-openings, in which case one or more through-openings may be located outside the convex section of the shield element.

[0024] By way of example, the convex section of the shielding element is at a distance of at most 1 mm, preferably at most 500 μm, preferably at most 100 μm, preferably at most 50 μm, preferably at most 25 μm, more preferably at most 10 μm from the sample during analysis or processing of the sample with the particle beam. The smaller the distance, the less effect the electrical interference field can have on the particle beam.

[0025] As a result, the particle beam can be controlled very precisely and is less susceptible to random and / or uncontrollable interference, allowing for very high resolution both during image acquisition, such as in a scanning electron microscope, and during processing methods performed with the particle beam, such as particle-beam-induced etching or deposition processes, ion implantation, and / or further structural modification processes.

[0026] The supply unit is, for example, an electron column capable of supplying an electron beam with an energy in the range of 10 eV to 10 keV and a current in the range of 1 μA to 1 pA. However, it may also be an ion source supplying an ion beam. The focused particle beam is preferably focused on the surface of the sample, achieving an irradiation area with a diameter in the range of 1 nm to 100 nm, for example.

[0027] The shielding element has a length and width in the range of, for example, 1 mm to 50 mm.

[0028] The material thickness of the shielding element is, for example, in the range of 1 nm to 100 μm, preferably 10 nm to 100 μm, preferably 100 nm to 50 μm, more preferably 1 μm to 30 μm, and even more preferably 5 μm to 15 μm. The material thickness of the shielding element is selected in a suitable manner, in particular depending on the expected mechanical and / or thermal loads, for example due to pressure differences, electrostatic forces, etc. If it is intended to achieve a particularly thin material thickness, the shielding element can, for example, be embodied in the form of a membrane or as a self-supporting film.

[0029] The through opening is e.g. 100 μm 2 ~2500μm 2 , preferably 400 μm 2 ~1600μm 2 , more preferably 750 μm 2 ~1400μm 2 The cross-sectional area is in the range of

[0030] The through opening has a diameter in the range of, for example, 10 μm to 50 μm, preferably 20 μm to 40 μm, more preferably 25 μm to 35 μm. The diameter relates to, for example, the distance between two oppositely arranged points of the through opening.

[0031] The convex section has for example a diameter in the range 100 μm to 5 mm, preferably 500 μm to 3 mm, preferably 1 mm to 2 mm, and for example extends over a distance of at least 10 μm, preferably at least 50 μm, preferably at least 100 μm in the direction towards the sample stage, i.e. the difference between the distance between the closest point from the shielding element and the sample stage and the distance between the farthest point from the shielding element and the sample stage is at least 10 μm, preferably at least 50 μm, preferably at least 100 μm.

[0032] According to one embodiment of the apparatus, the apparatus includes a gas delivery section configured to deliver a process gas through a through opening in the shield element to a processing location on the specimen.

[0033] In this embodiment, the process gas flows through the through opening in the direction of the particle beam. In this embodiment, it is advantageous to make the flow resistance to the through opening as low as possible so that the process gas can be efficiently directed to the processing location in a targeted manner. Furthermore, an aperture may be provided that restricts the gas flow toward the supply unit in a direction opposite to the particle beam. In this case, the process gas is fed, for example, into the region between the shield element and the aperture. If the shield element has multiple openings, the process gas can flow through each of the multiple openings, which may be advantageous for reducing the flow resistance.

[0034] According to a further embodiment of the apparatus, the apparatus comprises a gas supply configured to supply a process gas into a gap, the gap being formed by a sample arranged on the sample stage and by the shielding element.

[0035] The process gas flows through this gap to the processing location above the sample. This embodiment is advantageous because the process gas delivery to the processing location can be better controlled in this way. In particular, the process gas flow entering the supply unit opposite the beam direction is reduced because only the through-opening is available. As a result, corrosion of the supply unit, especially of the detector elements, due to contact with the process gas and / or reactive molecules formed from the process gas can be reduced.

[0036] The supply unit has, for example, a circulation plate with openings for the particle beam. The gas supply is carried out, for example, through the circulation plate by means of supply openings on the side of the circulation plate facing the sample. The process gas can then enter the gap between the sample and the shield element and flow to the processing position.

[0037] The specimen may be, for example, a lithography mask with a feature size in the range of 10 nm to 10 μm. This may be, for example, a transmissive lithography mask for DUV lithography (DUV: "deep ultraviolet", operating light wavelength range 30-250 nm) or a reflective lithography mask for EUV lithography (EUV: "extreme ultraviolet", operating light wavelength range 1-30 nm). The treatment processes performed in this case may include, for example, etching processes in which material is locally removed from the specimen's surface, deposition processes in which material is locally applied to the specimen's surface, and / or similar local activation processes, such as the formation of a passivation layer or the compression of a layer.

[0038] Suitable process gases for the deposition of materials or for the growth of tall structures are in particular alkyl compounds of main group elements, metals, or transition elements, such as cyclopentadienyltrimethylplatinum CpPtMe3 (Me=CH4), methylcyclopentadienyltrimethylplatinum MeCpPtMe3, tetramethyltin SnMe4, trimethylgallium GaMe3, ferrocene Cp2Fe, bis-allylchromium Ar2Cr, and / or carbonyl compounds of main group elements, metals, or transition elements, such as chromium hexacarbonyl Cr(CO)6, molybdenum hexacarbonyl Mo(CO)6, tungsten hexacarbonyl W(CO)6, dicobalt octacarbonyl Co2(CO)8, triruthenium dodecacarbonyl Ru3(CO). 12 , iron pentacarbonyl Fe(CO)5, etc., and / or alkoxide compounds of main group elements, metals, or transition elements, such as tetraethyl orthosilicate Si(OC2H5)4, tetraisopropoxytitanium Ti(OC3H7)4, etc., and / or halide compounds of main group elements, metals, or transition elements, such as tungsten hexafluoride WF6, tungsten hexachloride WCl6, titanium tetrachloride TiCl4, boron trifluoride BF3, silicon tetrachloride SiCl4, etc., and / or complexes containing main group elements, metals, or transition elements, such as copper bis-(hexafluoroacetylacetonate) Cu(C5F6HO2)2, dimethyl gold trifluoroacetylacetonate Me2Au(C5F3H4O2), etc., and / or organic compounds, such as carbon monoxide CO, carbon dioxide CO2, aliphatic and / or aromatic hydrocarbons, etc.

[0039] Suitable process gases suitable for etching materials are, for example, xenon difluoride XeF2, xenon dichloride XeCl2, xenon tetrachloride XeCl4, water vapor HO, heavy water DO, oxygen O2, ozone O3, ammonia NH3, nitrosyl chloride NOCl, and / or one of the following halide compounds: XNO, XONO2, X2O, XO2, X2O2, X2O4, X2O6, where X is a halide. Further process gases for etching materials are specified in applicant's U.S. patent application Ser. No. 13 / 0103281.

[0040] Examples of additive gases that can be mixed with the process gas in certain proportions, for example, to better control the treatment process, include oxidizing gases such as hydrogen peroxide HO, nitrous oxide NO, nitrogen oxide NO, nitrogen dioxide NO, nitric acid HNO, and other oxygen-containing gases; and / or halides such as chlorine Cl, hydrogen chloride HCl, hydrogen fluoride HF, iodine I, hydrogen iodide HI, bromine Br, hydrogen bromide HBr, phosphorus trichloride PCl, phosphorus pentachloride PCl, phosphorus trifluoride PF, and other halogen-containing gases; and / or reducing gases such as hydrogen H, ammonia NH, methane CH, and other hydrogen-containing gases. The additive gases can be used, for example, as buffer gases in etching processes, as passivation media, etc.

[0041] According to a further embodiment of the device, the gas feed comprises a feed channel integrated into the shield element.

[0042] This embodiment allows the process gas to be guided very precisely to the processing location. This increases the speed and efficiency of the particle beam induced processing process, since there is always a sufficient amount of process gas molecules present, preventing depletion. In this embodiment, the shielding element is produced by a special manufacturing method, in particular the LIGA manufacturing method (LIGA: an abbreviation from the German words Lithographie, Galvanik und Abformung [lithography, electroplating, and forming]).

[0043] The shield element can be embodied, for example, as a partially hollow element, in which case the interior of the shield element forms a feed channel. At the outer edge of the shield element, the interior is fluidly connected to the gas feed. In this case, transition or damping pieces can be used. Advantageously, the outlet opening for the gas feed is arranged as close as possible to the through opening in the convex region.

[0044] In a further example, the shield element comprises a microporous material covered with a gas-tight coating having an inlet for feeding the process gas and an outlet for the process gas to exit, the outlet preferably being formed in the convex section opposite the processing location.

[0045] In some embodiments of the device, the device is configured to establish electrical contact with the sample by the convex section of the shielding element, which can be advantageous, especially for samples with conductive surfaces, because charge can flow away directly from the surface of the sample, so that no disruptive electric fields are formed.

[0046] In a further embodiment, a protective layer can be deposited on the surface of the sample around the processing location by a particle beam induced process before the sample comes into contact with the shield element. The protective layer has advantageous electrical conductivity and serves as protection against mechanical damage to the sample caused by the shield unit when it is in contact with the sample. The protective layer can be removed again after the analysis or processing is complete, for example by a particle beam induced etching process.

[0047] According to a further embodiment of the apparatus, the through opening comprises a point of minimum distance between the shield element and the sample stage.

[0048] This is understood to mean that the geometrically smallest distance between the shield element and the sample stage if the shield element did not have an opening exists at the point of the shield element occupied by the through-opening, in which case in particular the edge of the through-opening forms the point of the shield element closest to the sample stage.

[0049] According to a further embodiment of the device, the shielding element comprises a planar section from which a convex section extends in the direction of the sample stage.

[0050] The planar section may, for example, serve to secure the shielding element to the delivery device, for example to a retaining structure at the edge of the opening. The planar section preferably extends substantially parallel to the surface of the sample during analysis or processing of the sample.

[0051] The planar section of the shielding element may be made from a different material than the convex section of the shielding element, in which case the shielding element may be composed of two parts, the planar section and the concave section, which may be screwed together, adhesively bonded to each other, welded to each other, and / or connected to each other by corresponding suitable engaging elements.

[0052] According to a further embodiment of the device, the convex section is embodied in a funnel-shaped manner, in particular with a circular cross section.

[0053] The convex sections can also be said to form the surface of a solid of revolution based on a convex function.

[0054] However, the convex section may also have a cross section that deviates from a circular shape, in particular an elliptical cross section.

[0055] Preferably, the convex section is embodied so as to taper towards the through opening.

[0056] According to a further embodiment, the convex section is embodied in such a way that a connecting line connecting two points on the surface of the convex section of the shielding element exists outside the shielding element for any combination of two points on the surface of the convex section of the shielding element.

[0057] A convex section can also be said to form an area that satisfies the mathematical requirement of being strictly convex: a function is strictly convex if it requires that the left-hand side of equation (1) be strictly "less than" the right-hand side.

[0058] An example of an area with this shape is a sphere or a section of a sphere. Furthermore, a strictly convex function, such as a parabola, will generate a corresponding area, for example a paraboloid of revolution, when a body of revolution is formed based on this function.

[0059] The existence of a connecting line outside is understood to mean that the connecting line has no common point with the convex section. From this it follows that this connecting line also does not intersect with the convex section or the shield element. It should be noted that a planar area does not satisfy this embodiment, since the connecting line between two points of the plane itself exists within the plane.

[0060] According to a further embodiment of the device, the shielding element comprises on its surface a layer of electrically conductive material, the layer thickness of which is equal to or greater than the penetration depth of the particles of the particle beam into the material.

[0061] This has the advantage that charge cannot build up in or on the shield element itself - for example, materials that can form a native oxide layer that is a poor conductor may be less suitable.

[0062] In an advantageous embodiment, the shielding element consists entirely of a conductive material, which may be a pure material, or else an alloy, a composite material, and / or a material with a microstructure.

[0063] The requirements for the material depend on the specific application. In addition to electrical conductivity, the magnetic and chemical properties of the material may be relevant. Preferably, the material is, for example, non-magnetic. Furthermore, the material is preferably chemically inert, so that it reacts only slightly or not at all with the process gases fed in and / or with other reaction products. This allows for a long service life of the shielding element.

[0064] The shielding element may comprise, for example, a noble metal. For example, the shielding element may comprise at least one element from the list including gold, nickel, palladium, platinum, and iridium. In some embodiments, the shielding element is formed of gold or nickel.

[0065] The shielding element preferably has a very smooth surface, for example with an RMS value of the surface roughness of at most 50 nm, preferably at most 10 nm, preferably at most 5 nm, more preferably at most 2 nm.

[0066] According to a further embodiment of the device, the shielding element has exactly one through opening.

[0067] It can also be said that the shielding element is embodied as a single-hole diaphragm, with the through-opening preferably being circular, but can also have further opening geometries such as square, hexagonal, octagonal, rectangular, and / or elliptical.

[0068] The through-opening defining the sidewall of the shield element is preferably inclined with respect to the axis of symmetry of the through-opening, so that the sidewall forms a cone that opens upward facing the beam direction. As a result, the opening cross section of the through-opening on the sample side is smaller than that on the opposite side. This has the advantage that secondary electrons or backscattered electrons from the sample can be detected over a larger solid angle. This can improve detection efficiency, signal-to-noise ratio, and / or resolution.

[0069] According to a further embodiment of the device, the shielding element has a plurality of through openings separated from one another by webs.

[0070] The web is formed, for example, by the material of the shield element that is present between two through-openings and separates them from each other. The web preferably has the smallest possible width. Depending on the geometry of the through-openings, the web may have a constant width or may have a variable width. For example, the web has a width in the range of 1 μm to 100 μm, preferably 1 μm to 50 μm, preferably 5 μm to 30 μm, more preferably 10 μm to 20 μm.

[0071] It can also be said that the shielding element forms a mesh or is formed by a mesh.

[0072] A shielding element having multiple through-openings advantageously allows the particle beam to reach a larger section of the sample or of the sample's surface without compromising the electric field shielding. It can also be said that the processing position or processing area can be enlarged. As a result, an improved overview can be achieved. However, in the case of multiple through-openings, an increase in the gas flow opposite to the beam direction can be evident when gas is fed into the gap between the sample and the shielding element.

[0073] If the shielding element has multiple through openings, the through openings are preferably arranged close to the periphery of the deepest point of the convex section of the shielding element, e.g., the deepest through opening comprises the deepest point of the convex section, with further through openings arranged in a manner directly adjacent to the deepest through opening.

[0074] By way of example, the convex section may be embodied such that instead of the deepest point there is a deepest planar region, with a plurality of through openings disposed within said region.

[0075] According to a further embodiment of the device, the through openings each have a hexagonal cross section.

[0076] The geometry of the through opening affects the field profile of the electric field to be shielded below the through opening, and may also affect particle radiation.

[0077] The hexagonal geometry allows for a high area coverage, which provides a good trade-off with further electrostatic properties.

[0078] Further possible geometries include square geometries, rectangular geometries, circular geometries, elliptical geometries, pentagonal geometries, octagonal geometries, and the like.

[0079] The arrangement of the through openings relative to one another may be regular or may be irregular. Furthermore, the through openings may be arranged in a manner that is rotated relative to one another about an axis of symmetry.

[0080] According to a further embodiment of the device, the web is shaped such that the cross-sectional area on the sample stage side of each of the plurality of through-openings in a first plane perpendicular to the surface normal of the shield element on the through-opening is smaller than the cross-sectional area on the opening side of the corresponding through-opening in a second plane parallel to the first plane.

[0081] According to a further embodiment of the device, one of the plurality of through openings has a geometric feature that distinguishes it from further through openings.

[0082] This embodiment is advantageous, for example, when the through-openings all have the same geometric shape and are regularly arranged, because in that case it may be difficult to distinguish the through-openings from one another. In this case, it is therefore possible to identify the through-openings, for example, including the point of the shield element that is at the smallest distance from the sample stage or the sample. It can also be said that the through-openings with the geometric feature mark a reference position, based on which the positions of further through-openings can be determined without ambiguity.

[0083] By way of example, the distinguishable through openings may have markings, which may be formed by sections with additional material and / or by sections with missing material.

[0084] It is also possible for the plurality of through openings to have markings or the like that allow them to be distinguished from one another, in which case there will be a plurality of marked through openings that can be determined without ambiguity.

[0085] A through opening having this geometric feature may have a different geometry than further through openings. For example, two through openings may be connected to form a single through opening, in which case the through opening forms a double through opening.

[0086] Proceeding from the distinguishable through openings, it is possible to determine the deepest through opening, which is particularly suitable for the analysis and / or treatment process, since the shielding of the electric field is best at this through opening.

[0087] According to a further embodiment of the device, one of the plurality of through openings comprises a point at which the distance between the shield element and the sample stage is smallest, and a further through opening is arranged symmetrically with respect to this one through opening.

[0088] The arrangement of the through openings may in particular be rotationally symmetric and / or mirror symmetric. A symmetric arrangement may have at least one axis of symmetry.

[0089] According to a further embodiment of the apparatus, the apparatus comprises a beam generating unit and a beam guiding element, the beam guiding element being arranged between the beam generating unit and the shielding element and configured to guide the particle beam, and further comprising a voltage source for applying a voltage between the shielding element and the beam guiding element.

[0090] The beam generating unit is configured to generate a particle beam, e.g., a hot cathode for generating an electron beam. The beam guiding unit is configured to, e.g., accelerate particles in the particle beam. The beam guiding unit may be configured to deflect the particle beam, e.g., to shape the particle beam, to focus the particle beam, etc.

[0091] Applying a voltage between the shielding element and the beam directing element generates an electric field between these elements. The particle beam passes through this field and can be affected accordingly, e.g., accelerated, decelerated, shaped, and / or deflected by the electric field, thereby directly influencing the particle beam all the way to the surface of the sample.

[0092] The trajectory of charged particles emanating from the sample and traveling through the opening opposite the particle beam direction is also affected by the electric field. For example, by appropriately setting the potentials of the shielding elements and the beam guiding elements, it is possible to establish an energy filter for secondary electrons and backscattered electrons. In this case, the sample or sample stage is suitable as a reference point, and the energy filter, e.g., the shielding elements, have a negative potential and the beam guiding elements have a positive potential relative to the sample or sample stage.

[0093] Furthermore, the shield element having a specific potential also generates an electric field between the shield element and the sample. This electric field can be set to better extract secondary electrons from structures deep on the surface of the sample. For this purpose, it is advantageous if the shield element has a positive potential with respect to the sample or sample stage. This has the advantage that the detection of electrons emitted from deeper regions on a sample with a high aspect ratio can be improved. The aspect ratio is understood to mean, for example, the ratio of the height to the width of a structure. For example, a height / width ratio of ≥ 0.5 indicates a high aspect ratio. This has the further advantage that, for example, secondary electrons emitted by the shield element can be captured. As a result, unwanted chemical reactions that may be initiated by such secondary electrons can be avoided.

[0094] In embodiments of the device, the shield element is fixed to the supply unit by a retaining device.

[0095] The connection between the holding device and the shielding element can be performed, for example, by welding, clamping and / or by adhesive bonding.

[0096] In some embodiments, the holding device and the shielding element are embodied as one component, in particular integrally, which is made possible by special manufacturing methods, in particular the LIGA manufacturing method (LIGA: abbreviation from the German words Lithographie, Galvanik und Abformung [lithography, electroplating, and forming]).

[0097] According to a further embodiment of the device, the shielding unit is fixed to the supply unit by a holding device, in which case the holding device and the shielding element are electrically insulated from each other, and a further voltage source is provided for applying a voltage between the holding device and the beam guiding element and / or the shielding element.

[0098] In this embodiment, two electric fields are formed: a first electric field exists between the beam guiding element and the holding device, and a second electric field exists between the holding device and the shielding element. This results in two electric field sections below the beam guiding element, which can be used to focus, for example, the particle beam, without using magnetic focusing, which can lead to remnant polarization effects, for example.

[0099] If the particle beam is an electron beam, the holding device is preferably set to a negative potential relative to the beam guiding element, which slows down the electrons. For example, the energy of the electron beam, which is given higher energy than the desired incident energy on the sample, also called boost voltage or Uboost, can be set to the desired energy.

[0100] According to a further embodiment of the device, the shielding element is held in an electrically insulating manner and a detection unit is provided for detecting a current flowing away from the shielding element.

[0101] The detection unit, e.g., a current measuring device, can be used as a detector in various ways. In particular, in cooperation with a voltage applied between the shielding element and the holding device or beam directing element, which acts as an energy filter, it is possible to distinguish secondary electrons with low energies, e.g., in the range of a few electron volts to a few tens of electron volts, from backscattered electrons with higher energies within the beam energy range. The shielding element can then be used, for example, as a secondary electron detector.

[0102] Since the backscattering efficiency of the backscattered electrons depends on the electron energy and the atomic number of the material, the energy filter can also provide information about the atomic number of the material.

[0103] Furthermore, the gas pressure in the region of the shield element can be inferred from the detected current because there is a positive correlation between gas pressure and current: increasing gas pressure results in more collisions between particles of the particle beam and gas molecules, thus causing more scattering, which results in more particles being scattered onto the shield element and therefore a larger detected current.

[0104] According to a further embodiment of the device, the shielding element comprises a plurality of sections that are electrically insulated from one another and define through openings, in which case a voltage can be applied between in each case two sections arranged opposite each other by a corresponding voltage source.

[0105] In this way, the shield element can additionally be used as a deflection unit. Therefore, a separate deflection unit arranged above the shield element can be omitted. This simplifies the structure of the device and also improves its efficiency. First, the solid angle in which backscattered or secondary electrons can be detected is not further reduced by a separate deflection unit. Second, since the through-opening has a diameter of, for example, only 30 μm to 150 μm, the voltage at which the deflection unit operates can be lowered. The smaller the through-opening, the greater the gradient of the electric field for the same voltage.

[0106] Preferably, the shield unit comprises eight such sections, and the shield unit can then also be called an octopole unit.

[0107] In this embodiment, the shielding element may also be used as a stigmator and / or a lens for the particle beam, in particular for focusing the particle beam onto the sample. The stigmator is configured to correct astigmatism.

[0108] Furthermore, the shield element can also serve as a "beam blanker." In conventional particle beam columns, a beam blanker (used to quickly switch the particle beam off and on) is located in the column at a position where the particles have high energy, and for this reason, it is also necessary to use high voltages to deflect the particle beam. In contrast, in this embodiment, the beam is deflected at a position where its energy has already decreased, and for this reason, such high voltages are not required. Therefore, the structure can be simplified and faster switching times are possible. A current measuring device can also be used to determine the current of the particle beam when it is directed at the shield element.

[0109] In embodiments, a capacitance measuring device may be provided that is configured to ascertain the capacitance between the shield element and the sample.

[0110] For example, the distance between the shielding element and the sample can be ascertained on the basis of capacitance, which is particularly possible in the case of samples that are conductive or have conductive sections.

[0111] According to a further embodiment of the device, a plurality of shielding elements are provided, arranged one next to the other along the beam direction and each covering an aperture, at least one of the plurality of shielding elements being held in a displaceable manner in order to provide an aperture with a settable aperture.

[0112] The displaceably held shield element may allow the relative position of the displaceably held shield element to be set relative to the further shield element. This results in an opening with a settable beam direction. By reducing the size of the opening, it is possible to reduce, for example, the process gas volume flow rate opposite the beam direction.

[0113] The shield element is preferably positioned relative to the aperture such that variations in focus within a predetermined focus interval and / or variations in beam energy within a predetermined energy interval have minimal effect on beam position and / or minimal effect on detection efficiency.

[0114] The process of fluctuating focus and / or beam energy is sometimes called "wobble."

[0115] This positioning of the shielding elements is set specifically once for each supply unit when the shielding elements are attached to the supply unit. The positional optimization as described above ensures that the device has a high robustness, particularly with regard to resolution.

[0116] According to a second aspect, a method for analyzing and / or processing a sample with a particle beam using the device according to the first aspect is proposed. In a first step, the sample is placed on a sample stage. In a second step, a particle beam is supplied. In a third step, the particle beam is emitted through a through opening to a processing location on the sample.

[0117] This method has the same advantages as those already described for the device.

[0118] The embodiments and features described with respect to the device also apply mutatis mutandis to the proposed method and vice versa.

[0119] According to one embodiment of the method, the method additionally includes a step of delivering process gas to the processing position, wherein the process gas flows to the processing position on the sample only through a gap formed by the shield unit and the sample.

[0120] According to a further embodiment of the method, the method includes contacting a surface of the specimen with a shield element, wherein a convex section of the shield element has at least one contact point with the surface of the specimen.

[0121] If the sample has a conductive surface, the charge can flow away via the electrical contacts and the shield unit, thus avoiding charging the entire sample.

[0122] In the case of sensitive samples, a protective layer can be provided that is locally deposited on the surface of the sample beforehand. The protective layer is formed, for example, in the area surrounding the processing position where the shield element first comes into contact with the sample. The protective layer can be produced in particular by a particle beam induced process. The protective layer has advantageous electrical conductivity. The protective layer is preferably made of a material that can be removed again by a selective etching process without leaving any residue or damaging the surface of the sample. The protective layer can be removed again in a subsequent purge process or in a particle beam induced etching process.

[0123] "One" in this context should not necessarily be understood as limiting to exactly one element. Rather, multiple elements may be provided, e.g., two, three, or more. Any other numbers used herein should not be understood as meaning that there is a limit to the exact number of elements stated. Rather, deviations up or down in number are possible unless otherwise indicated.

[0124] Further possible implementations of the present invention also include not explicitly mentioned combinations of the features or embodiments mentioned above or below with respect to the exemplary embodiments, in which case the skilled person will also add individual aspects as improvements or supplements to the respective basic form of the invention.

[0125] Further advantageous configurations and aspects of the invention are the subject of the dependent claims and of the exemplary embodiments of the invention described below. In the following text, the invention is explained in more detail on the basis of preferred embodiments with reference to the attached drawings. [Brief explanation of the drawings]

[0126] [Figure 1] 1 is a schematic diagram of a first exemplary embodiment of an apparatus for analyzing and / or processing a sample with a particle beam; [Figure 2] 1 is an excerpt from a schematic diagram of a second exemplary embodiment of an apparatus for analyzing and / or treating a sample with a particle beam; [Figure 3] 10 is an excerpt from a schematic diagram of a third exemplary embodiment of an apparatus for analyzing and / or treating a sample with a particle beam; [Figure 4] 1A-1C are diagrams illustrating six different exemplary embodiments of a shield element. [Figure 5] 2A and 2B are schematic diagrams illustrating a cross section through one exemplary embodiment of a shield element. [Figure 6] 10A-10C show schematic views of further exemplary embodiments of shielding elements; [Figure 7]10 is a schematic diagram of a fourth exemplary embodiment of an apparatus for analyzing and / or processing a sample with a particle beam; [Figure 8] 10 is a schematic diagram of a fifth exemplary embodiment of an apparatus for analyzing and / or processing a sample with a particle beam; [Figure 9] 10A-10C show schematic views of further exemplary embodiments of shielding elements; [Figure 10] 10 shows a schematic diagram of an excerpt from a sixth exemplary embodiment of an apparatus for analyzing and / or treating a sample with a particle beam; [Figure 11] 1 is a schematic block diagram of one exemplary embodiment of a method for analyzing and / or processing a sample with a particle beam. [Figure 12] 10 shows a schematic diagram of an excerpt from a seventh exemplary embodiment of an apparatus for analyzing and / or treating a sample with a particle beam; [Figure 13] 10 is an excerpt from a schematic diagram of an eighth exemplary embodiment of an apparatus for analyzing and / or processing a sample with a particle beam. [Figures 14A-14D] 10A-10C each show a cross section through a shield element in several different embodiments. [Figure 15] FIG. 10 is a schematic diagram for explaining the term "convex." DETAILED DESCRIPTION OF THE INVENTION

[0127] Identical elements or elements with identical functions are given the same reference numerals in the figures unless otherwise indicated. It should also be noted that the depictions in the figures are not necessarily drawn to scale.

[0128] 1 shows a schematic diagram of a first exemplary embodiment of an apparatus 100 for analyzing and / or processing a sample 200 (see FIG. 2, FIG. 3, or FIG. 12) with a particle beam 112. The apparatus 100 is preferably arranged in a vacuum housing (not shown). The apparatus 100 comprises a supply unit 110 for supplying the particle beam 112 and a sample stage 120 for holding the sample 200, the sample stage being arranged below the supply unit 110.

[0129] The supply unit 110 in particular comprises a particle beam generation unit 111 for generating a particle beam 112. The particle beam 112 consists of charged particles, for example ions, or electrons. In the example of FIG. 1, an electron beam is involved. The supply unit 110 is therefore also called an electron column, in which case the device 100 forms, for example, a scanning electron microscope. The electron beam 112 is guided by beam guidance elements (not shown in FIG. 1), also called an electron optical unit. Furthermore, the electron column 110 of FIG. 1 comprises a detector (not shown) for detecting electron signals emanating, for example, from backscattered electrons and / or from secondary electrons.

[0130] The electron column 110 is, for example, 10 -7 mbar~10 -8The device 100 has a dedicated vacuum housing, which is evacuated to a residual gas pressure of 100 mbar. An opening 114 for the electron beam 112 is located on the underside. The opening 114 is covered by a shielding element 116. The shielding element 116 is embodied in a sheet-like manner and comprises a conductive material. For example, the shielding element 116 is made of gold. The shielding element 116 has a convex section 117 that is convex toward the sample stage 120. The convex section 117 is curved toward the sample stage 120. The convex section 117 has a through-opening 118 through which the particle beam 112 passes. The through-opening 118 particularly includes the point of the convex section 117 closest to the sample stage 120. The distance between the shielding element 116 and the sample stage 120 is therefore smallest in the region of the through-opening 118. During operation of the device 100, the distance between the through-opening 118 and the sample 200 is preferably 5 μm to 30 μm, preferably 10 μm. Preferably, the sample stage 120 has a positioning unit (not shown) by which the distance between the sample stage 120 and the electron column 110 can be set.

[0131] The shield element 116 may have a planar region 116A (see FIGS. 14A-14D) from which a convex section 117 projects. The planar region 116A preferably extends radially from an upper end of the convex section 117. The shield element 116 is secured to the opening 114 of the electron column 110, for example, at the outer edge of the planar region 116A.

[0132] A ground potential is applied to the shield element 116. The shield element is therefore configured to shield the electric field E. For clarity, FIG. 1 illustrates, by way of example, an electric charge Q that generates the electric field E. The electric charge Q is illustrated below the shield element 116 in a region where a processing region 202 (see FIG. 2, FIG. 3, or FIG. 12) of the sample 200 is expected to be located during use of the apparatus 100. In particular, in the case of a sample 200 that is (at least partially) non-conductive or only slightly conductive, when the particle beam 112 is incident on the sample 200, charging of the sample 200 and thus the formation of an electric field E occurs, as illustrated in FIG. 1. FIG. 1 illustrates, by way of example, a negative electric charge Q that results from the incidence of the electron beam 112.

[0133] As a result of shielding the electric field E, firstly, increased accuracy is achieved for the impact point on the sample 200 and also for the focusing position of the electron beam 112, which improves resolution and process control. Secondly, the flight trajectories of backscattered electrons and secondary electrons flying opposite the electron beam 112 towards the beam supply unit 111 are not significantly affected, which also improves resolution and process control, and further sensitivity.

[0134] Figure 2 shows an excerpt from a schematic diagram of a second exemplary embodiment of an apparatus 100 for analyzing and / or treating a sample 200 with a particle beam 112. Unless otherwise described below, the apparatus 100 of Figure 2 may have the same features as the apparatus 100 of Figure 1. The example shown is specifically configured to perform particle beam induced treatment processes.

[0135] During operation of the apparatus 100, the sample stage 120, on whose surface the sample 200 is arranged, is positioned below the supply unit 110 such that the through opening 118 is disposed above a processing position 202 on the sample 200 in the beam direction. A gap is formed between the sample 200 and the supply unit 110, in particular the shield element 116.

[0136] In this example, the supply unit 110 has a gas supply 130 configured to supply process gas PG into the gap. The process gas PG flows along the gap and thereby reaches the processing location 202 on the sample 200. The gas supply 130 thus firstly ensures that sufficient process gas PG is supplied to the processing location 202, and secondly, the volumetric flow rate of the process gas PG entering the supply unit 110 through the through-opening 118 is relatively small, and in particular is much smaller than if the process gas PG were guided from above to the processing location 202 through the through-opening 118.

[0137] The sample 200 may be, for example, a lithography mask having a feature size in the range of 10 nm to 10 μm. It may be, for example, a transmissive lithography mask for DUV lithography (DUV: "deep ultraviolet", operating light wavelength range 30-250 nm) or a reflective lithography mask for EUV lithography (EUV: "extreme ultraviolet", operating light wavelength range 1-30 nm). Treatment processes performed in this case may include, for example, etching processes in which material is locally removed from the surface of the sample 200, deposition processes in which material is locally applied to the surface of the sample 200, and / or similar local activation processes, such as the formation of a passivation layer or the compression of a layer.

[0138] The process gas PG can contain a mixture of gaseous substances. Suitable process gases PG for the deposition of materials or for the growth of tall structures are in particular alkyl compounds of main group elements, metals, or transition elements. Examples of these are cyclopentadienyltrimethylplatinum CpPtMe3 (Me=CH4), methylcyclopentadienyltrimethylplatinum MeCpPtMe3, tetramethyltin SnMe4, trimethylgallium GaMe3, ferrocene Cp2Fe, bis-allylchromium Ar2Cr, and / or carbonyl compounds of main group elements, metals, or transition elements, such as chromium hexacarbonyl Cr(CO)6, molybdenum hexacarbonyl Mo(CO)6, tungsten hexacarbonyl W(CO)6, dicobalt octacarbonyl Co2(CO)8, triruthenium dodecacarbonyl Ru3(CO). 12 , iron pentacarbonyl Fe(CO)5, etc., and / or alkoxide compounds of main group elements, metals, or transition elements, such as tetraethyl orthosilicate Si(OC2H5)4, tetraisopropoxytitanium Ti(OC3H7)4, etc., and / or halide compounds of main group elements, metals, or transition elements, such as tungsten hexafluoride WF6, tungsten hexachloride WCl6, titanium tetrachloride TiCl4, boron trifluoride BF3, silicon tetrachloride SiCl4, etc., and / or complexes containing main group elements, metals, or transition elements, such as copper bis-(hexafluoroacetylacetonate) Cu(C5F6HO2)2, dimethyl gold trifluoroacetylacetonate Me2Au(C5F3H4O2), etc., and / or organic compounds, such as carbon monoxide CO, carbon dioxide CO2, aliphatic and / or aromatic hydrocarbons, etc.

[0139] Suitable process gases suitable for etching materials are, for example, xenon difluoride XeF2, xenon dichloride XeCl2, xenon tetrachloride XeCl4, water vapor H2O, heavy water DO, oxygen O2, ozone O3, ammonia NH3, nitrosyl chloride NOCl, and / or one of the following halide compounds: XNO, XONO2, X2O, XO2, X2O2, X2O4, X2O6, where X is a halide.

[0140] Examples of additive gases that can be mixed with the process gas PG in certain proportions, for example, to better control the treatment process, include oxidizing gases such as hydrogen peroxide HO, nitrous oxide NO, nitrogen oxide NO, nitrogen dioxide NO, nitric acid HNO, and other oxygen-containing gases; and / or halides such as chlorine Cl, hydrogen chloride HCl, hydrogen fluoride HF, iodine I, hydrogen iodide HI, bromine Br, hydrogen bromide HBr, phosphorus trichloride PCl, phosphorus pentachloride PCl, phosphorus trifluoride PF, and other halogen-containing gases; and / or reducing gases such as hydrogen H, ammonia NH, methane CH, and other hydrogen-containing gases. The additive gases can be used, for example, as buffer gases in etching processes, as passivation media, etc.

[0141] 3 shows an excerpt from a schematic diagram of a third exemplary embodiment of an apparatus 100 for analyzing and / or processing a sample 200 with a particle beam 112. This includes, in particular, the specific embodiment of the apparatus 100 shown in FIG.

[0142] In this case, the shield element 116 comprises a channel that forms the final section of the path of the gas supply 130. In this case, the process gas PG is guided through the shield unit 116. In this way, the process gas PG can be brought very close to the processing position 202. As a result, leakage of the process gas PG to the surroundings of the apparatus 100 can be reduced, and consumption of the process gas PG can be suppressed. In particular, at the processing position 202, a higher process gas pressure and lower process gas consumption can be simultaneously achieved. As a result, the processing speed can be increased.

[0143] The shielding element 116 with the integrated gas feed is produced, for example, by a special manufacturing method, in particular the LIGA manufacturing method (LIGA: abbreviation from the German words Lithographie, Galvanik und Abformung [lithography, electroplating, and forming]).

[0144] FIG. 4 shows six different exemplary embodiments (A) to (F) of the shielding element 116. FIG. 4 shows the shielding element 116 in a plan view, e.g., from the beam direction, and for this reason the convex section 117 is shown in each case as a dotted line. By way of example, the convex section 117 starts from this line, and on the outside the shielding element can be embodied in a particularly planar manner. All the examples shown in FIG. 4 comprise shielding elements 116 with a circular outer edge, although geometries deviating therefrom are also possible. Each of the illustrated shielding elements 116 can be used in the device 100 according to any of FIGS. 1 to 3, 7, 8, 10, or 12.

[0145] In the example of Figure 4(A), the shielding element 116 is embodied in the form of a single-hole aperture. The shielding element 116 has a diameter of, for example, 4 mm, the through-opening 118 has a diameter of 30 µm, and the convex section 117 has a diameter of, for example, 2 mm.

[0146] In the example of FIG. 4(B), the shielding element 116 has a plurality of through-openings 118, although for clarity, only one of them is identified by a reference number. A web 119 is provided between the two through-openings 118, and the web is made of, for example, the material of the shielding element 116. By way of example, the shielding element 116 is formed of a gold film having a thickness of 10 μm, and the through-openings 118 are formed by a stamping method. In this example, the plurality of through-openings 118 are provided in a convex section 117 of the shielding element 116. In this example, the through-openings 118 all have the same size and geometric shape, but a plurality of through-openings 118 having different sizes and / or different geometric shapes may also be provided.

[0147] In the example of Fig. 4(C), the shield element 116 has a plurality of through openings 118, only one of which is identified by a reference number for clarity. The through openings 118 here all have a hexagonal geometric shape. Thus, each web 119 between two through openings 118 has a constant width. In this example, a plurality of through openings 118 is also provided in at least a portion of the convex section 117.

[0148] In the example of Fig. 4(D), the shielding element 116 has a plurality of through openings 118, only one of which is identified by a reference number for clarity. The through openings 118 here all have a square geometric shape. Thus, each web 119 between two through openings 118 has a constant width. In this example, a plurality of through openings 118 is also provided in at least a portion of the convex section 117.

[0149] In the example of Figure 4(E), the shielding element 116 has a plurality of through openings 118, only one of which is identified by a reference number for clarity. The through openings 118 here all have a hexagonal geometric shape, although through openings 118 of different sizes are provided.

[0150] The largest through-opening 118 is centrally located within the convex section 117. The central through-opening 118 comprises the point of the shield element 116 closest to the sample stage 120 (see FIGS. 1 to 3, 5, 7, 8, 10, or 12). The central through-opening 118 is preferably the through-opening 118 through which the particle beam 112 (see FIGS. 1 to 3, 7, 8, 10, or 12) for analyzing or processing the sample 200 is guided. Directly adjacent to the central through-opening 118, six smaller through-openings 118 are arranged. The webs 119 between these through-openings 118 have a web width of, for example, 10 μm. Further radially outward, a total of 12 further through-openings 118 are arranged, in particular arranged in a hexagonal pattern. The web width between these outer through-openings 118 is, for example, 50 μm.

[0151] In this example, the shield element 116 makes it possible, first, to generate an overview record of the sample 200 by scanning the particle beam 112 over each of the through openings 118, and second, while at the same time reducing the free cross-sectional area by the wide webs 119, thereby reducing the volumetric flow rate of the process gas through the shield element 116.

[0152] In the example of Fig. 4(F), the shielding element 116 has a plurality of through openings 118, only one of which is identified by a reference number for clarity. The through openings 118 here all have a hexagonal geometric shape. In this example, the through openings 118 are all of the same size, and the webs 119 have a constant width, e.g., 40 μm. The shielding element 116 of this example has, for example, the same advantages as the shielding element 116 of example (E).

[0153] 5 shows a schematic illustration of an excerpt from a cross section through one exemplary embodiment of a shield element 116 having a plurality of through openings 118, only one of which is shown in this excerpt of FIG. 5. The shield element 116 may be embodied, for example, as described with reference to FIGS. 1 to 4. The exit opening 118 is defined by two webs 119. The cross section of the webs 119 is formed in such a way that a sample stage-side cross-sectional area 118A in a first plane perpendicular to the surface normal N of the shield element 116 on the through opening 118 is smaller than an opening-side cross-sectional area 118B of the through opening 118 in a second plane parallel to the first plane.

[0154] The web 119 may be said to taper upward. The web 119 may be embodied, for example, as a triangular or trapezoidal shape. This cross-section allows backscattered or secondary electrons emitted by the sample 200 to be detected within a larger solid angle range relative to the shield element 116, as illustrated by the cone with an opening angle α depicted in FIG. 5 as an example.

[0155] As a result, the mechanical stability of the shield element 116 may remain the same, while the detection efficiency and / or resolution may be improved.

[0156] If the shield element 116 is embodied as a single-hole aperture (see FIG. 4(A)), for example, the sidewalls of the individual through-openings 118 are correspondingly shaped to achieve the same effect. For example, the sidewalls of the through-openings 118 form a cone (not shown).

[0157] 6 shows a schematic representation of a further exemplary embodiment of a shield element 116 embodied similarly to that of FIG. 4(F), except that one of the through openings 118 has a geometric feature. * The through opening 118 has two adjacent through openings 118 with the web 119 removed between them. * is therefore unambiguously distinguishable from the other through openings 118, thus enabling orientation. * 1 to 3, 5, 7, 8, 10, or 12, it is possible to find the central through-opening 118 that is closest to the sample stage 120.

[0158] 7 shows a schematic diagram of a third exemplary embodiment of an apparatus 100 for analyzing and / or processing a sample 200 (see FIG. 2, FIG. 3, or FIG. 12) with a particle beam 112. Unless otherwise described below, the apparatus 100 of FIG. 7 may have the same features as the apparatus 100 of any of FIG. 1, FIG. 2, or FIG. 3.

[0159] In this example, the supply unit 110 comprises a beam guiding element 113 arranged between the shielding element 116 and the beam generating unit 111. A voltage source U0 is configured to apply a certain acceleration voltage between the beam generating unit 111 and the beam guiding element 113. The charged particles of the particle beam 112 are thus accelerated in the direction of the beam guiding element 113.

[0160] The shield element 116 is, for example, held in an insulated manner from the supply unit 110. A further voltage source U1 is configured to apply a voltage between the beam guiding element 113 and the shield element 116. As a result, an electric field (not shown) is formed between the beam guiding element 113 and the shield element 116. This electric field is controllable by the voltage applied by the further voltage source U1. In this way, the particle beam 112 can be guided, in particular accelerated or decelerated and / or deflected, in the region between the beam guiding element 113 and the shield element 116. The same applies to charged particles emanating from the sample 200 and passing through the shield element 116 opposite the beam direction. It can also be said that the beam guiding element 113, together with the shield element 116 and the voltage source U1, form an electro-optical element.

[0161] As an alternative to the diagram of FIG. 7, a further voltage source U1 can be arranged between the beam guiding element 113, which is embodied as a pole piece, for example, and the shielding element 116.

[0162] 8 shows a schematic diagram of a fourth exemplary embodiment of an apparatus 100 for analyzing and / or treating a sample 200 (see FIG. 2, FIG. 3, or FIG. 12) with a particle beam 112. The apparatus 100 in this example has the same structure as the apparatus 100 in FIG. 7, except that the shielding element 116 is now replaced by a holding device 116. * The holding device 116 is additionally held by the * are embodied here as separate elements, and the shield element 116 is a retaining device 116 * An additional voltage source U2 is electrically isolated from the beam guiding element 113 and the holding device 116. * and a voltage is applied between the

[0163] Two electric fields (not shown) are arranged side by side along the beam direction, through which the particle beam 112 passes and which can thereby affect the particle beam 112. Many different electric field configurations can be set up using this structure.

[0164] As an alternative to the structure shown, an additional voltage source U2 can be connected to the holding device 116 * and the shield element 116.

[0165] As a further alternative, the retaining device 116 * and the beam guiding element 113, and a voltage source U1, and a holding device 116 * and the shield element 116 an additional voltage source U2 is disposed.

[0166] 8 also shows a current measuring device I1 configured to detect a current flowing away from the shielding element 116. The current measuring device I1 can be used as a detector in various ways. In particular, the shielding element 116 and the holding device 116 * Alternatively, in cooperation with a voltage applied between the beam directing element 113 and the shielding element 116, which acts as an energy filter, it is possible to distinguish secondary electrons having low energies, for example in the range of a few electron volts to a few tens of electron volts, from backscattered electrons having higher energies within the beam energy range. The shielding element 116 can then be used, for example, as a secondary electron detector.

[0167] Furthermore, the gas pressure in the region of the shield element 116 can be inferred from the detected current because there is a positive correlation between gas pressure and current. Increasing gas pressure results in more collisions between beam particles and gas molecules, thus causing more extensive scattering, which results in more particles being scattered into the shield element 116 and therefore a larger detected current.

[0168] 9 shows a schematic diagram of a further exemplary embodiment of the shield element 116, which here comprises eight mutually insulated sections Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb, each adjacent to a through-opening 118. A voltage can be applied to each of the opposing pairs of these sections, Ia-Ib, IIa-IIb, IIIa-IIIb, IVa-IVb, by controllable voltage sources UI, UII, UIII, UIV, respectively, assigned to said pair. This shield element 116, which forms a beam deflection element, allows additional control of the particle beam 112 (see FIGS. 1 to 3, 7, 8, 10, or 12).

[0169] 10 shows, in schematic form, an excerpt from a further exemplary embodiment of an apparatus 100 (see FIG. 2, FIG. 3, or FIG. 12) for analyzing and / or processing a sample 200 with a particle beam 112. Unless otherwise described below, the apparatus 100 of FIG. 10 may have the same features as the apparatus 100 of any of FIGS. 1-3, 7, or 8.

[0170] A special feature of this exemplary embodiment is that two shield elements 116 are arranged side by side in the beam direction, both shield elements covering the opening 114. In this case, one of the shield elements 116 is held by a positioning unit 140. This shield element 116 can be displaced relative to the shield element 116 fixedly arranged above it. In this way, the two shield elements 116 form a settable aperture. The positioning unit 140 in particular comprises one or more flexures and / or piezoelectric actuators, which allow the shield element 116 to be displaced along at least one axis. Preferably, the shield element 116 is displaceable along at least two axes. Additionally and / or alternatively, the shield element 116 can be held in a rotatable manner.

[0171] 11 shows a schematic block diagram of one exemplary embodiment of a method for analyzing and / or processing a sample 200 (see FIG. 2, 3, or 12) with a particle beam 112 (see FIGS. 1-3, 7, 8, 10, or 12). The method is preferably performed by one of the apparatuses 100 of FIGS. 1-3, 7, 8, 10, or 12.

[0172] In a first step S1, the specimen 200 is placed on the specimen stage 120. This may involve, for example, positioning the specimen 200 below the shield element 116 (see FIGS. 1-10 or 12) so that the through opening 118 (see FIGS. 1-10 or 12) is directly above a processing location 202 (see FIGS. 2, 3 or 12) on the specimen 200.

[0173] In a second step S2, a particle beam 112 is supplied, and in a third step S3, the particle beam 112 is emitted through the through opening 118 onto a processing position 202 on the sample 200, thus analyzing and / or processing the sample 200.

[0174] 12 shows a schematic diagram of a further exemplary embodiment of an apparatus for analyzing and / or processing a sample 200 with a particle beam 112. Unless otherwise described below, the apparatus 100 of FIG. 12 may have the same features as the apparatus 100 of any of FIGS. 1-3, 7, 8, or 10.

[0175] In this exemplary embodiment, the apparatus 100 is configured to establish electrical contact with the sample 200 through the convex section 117 of the shield element 116. This can be advantageous, particularly for samples 200 with conductive surfaces, because charges can flow directly away from the sample's surface, preventing the formation of disruptive electric fields. In this exemplary embodiment, before the sample 200 is brought into contact with the shield element 116, a protective layer 204 is deposited around the processing position 202 on the sample's surface by a particle-beam-induced process. The deposition process was carried out by the apparatus 100. For this purpose, for example, molybdenum hexacarbonyl Mo(CO)6 was used as the process gas PG (see FIG. 2 or FIG. 3). The protective layer 204 thus generated has advantageous electrical conductivity and also serves as a protection against mechanical damage to the sample 200 caused by the shield unit 116 when the shield unit 116 is in contact with the sample 200. After the analysis or processing is completed, the protective layer 204 can be removed again, for example, by a particle-beam-induced etching process.

[0176] 13 shows an excerpt from a schematic diagram of an eighth exemplary embodiment of an apparatus 100 for analyzing and / or processing a sample 200 with a particle beam 112. Unless otherwise described below, the apparatus 100 of FIG. 13 may have the same features as the apparatus 100 of any of FIGS. 1-3, 7, 8, 10, or 12.

[0177] In this example, the supply unit 110 includes a gas supply 130 configured to deliver a process gas PG to a processing position 202 on the sample 200 through the through opening 118 of the shield element 116. The process gas PG flows through the through opening 118 along the beam direction of the particle beam 112, thereby reaching the processing position 202 on the sample 200.

[0178] With this configuration of gas feed 130, there is a risk that the process gas PG will also flow towards the beam generating unit 111 in a direction opposite to the beam direction (see Figure 1, 7 or 8) and, for example, chemically react with elements in the supply unit 110. Therefore, in this example, an aperture 132 is provided above the nozzle or outlet of gas feed 130. The aperture 132 has a through opening for the particle beam 112. The aperture 132 prevents a free gas flow from flowing upwards opposite to the beam direction.

[0179] At the same time, a potential can be applied to the aperture 132, which allows it to be used for beam steering and / or otherwise used as a detector. In addition to the aperture 132, differential pumping stages can be provided (not shown), which further reduce the upward gas flow opposite to the beam direction.

[0180] 14A-14D each show a cross section through several different embodiments of the shield element 116. Each of the shield elements 116 shown in these figures may be used with the device 100 of FIGS. 1-3, 7, 8, 10, 12, or 13, among others.

[0181] 14A-14D all have a planar section 116A from which extends a convex section 117. The illustrated shielding elements 116 differ, particularly in the geometry of their respective convex sections 117. However, it should be noted that the planar section 116A is not a required feature of the shielding elements 116. In some embodiments (not shown), the shielding elements 116 do not include a planar section 116A. In further embodiments, the shielding elements 116 comprise a convex section 117.

[0182] Shield element 116 shown in FIG. 14A has a hemispherical convex section 117, with through opening 118 located at the deepest point of the hemisphere. It should be noted that convex section 117 need not constitute a perfect hemisphere. In further embodiments, convex section 117 constitutes a smaller section of a sphere. Furthermore, the shape need not be strictly spherical, but rather there may be deviations therefrom, for example, when the shape is compressed or stretched.

[0183] Figure 14B shows a shielding element 116 that is geometrically identical to that shown in Figure 14A, but which has further openings (not numbered) in addition to the through openings 118. It can also be said that the convex section 117 of the shielding element 116 is embodied as a net.

[0184] The shield element 116 shown in Figure 14C has a convex section 117 in the form of a paraboloid of revolution with a through opening 118 located at the deepest point of the paraboloid of revolution.

[0185] The shield element 116 shown in FIG. 14D has a convex section 117 in the form of a cone, with a through opening 118 located at the apex of the cone.

[0186] It should be noted that each of the shielding elements 116 illustrated in Figures 4(A)-4(F), 6, or 9 can be shaped as illustrated with reference to Figures 14A-14D. In other words, each of the shielding elements 116 illustrated in Figures 14A-14D can also have the additional features of the shielding elements 116 described with reference to Figures 4(A)-4(F), 6, or 9.

[0187] 14A-14C are examples of convex sections 117 that are strictly convex according to the mathematical definition. The term "convex" will be explained on the basis of an illustrative example with reference to FIG.

[0188] Figure 15 shows a schematic diagram to explain the term "convex". Figure 15 shows a curve 117, which represents, for example, the cutting edge of a cross section through the convex section 117. Two points P1, P2 on the curve 117 are highlighted. A connecting line LIN between these two points P1, P2 is also shown.

[0189] The curve 117 is convex, which can be recognized, for example, by the fact that the connecting line LIN for any random pair of points P1, P2 on the curve 117 lies outside the curve 117, as illustrated for two points P1, P2 as an example in FIG. 15.

[0190] Although the present invention has been described on the basis of exemplary embodiments, the present invention can be modified in various ways. In particular, the features and aspects described in the various exemplary embodiments can be combined with one another, even if not explicitly stated as such in the corresponding description of the exemplary embodiments. [Explanation of symbols]

[0191] 100 devices 110 Supply Unit 111 Beam generating unit 112 Particle beam 113 Beam steering element 114 Opening 116 Shield Elements 116 * holding device 116A Planar area 117 Convex Section 118 Through opening 118 * Through opening 118A cross section 118B Cross-sectional area 119 Web 120 Sample stage 130 Gas supply unit 132 aperture 140 Positioning unit 200 samples 202 Processing location 204 Protective layer Α Opening angle E electric field I1 Current measuring device Section Ia Ib Section Section IIa Section IIb Section IIIa Section IIIb Section IVa Section IVb LIN connection straight line P1 point P2 point PG Process Gas Q charge S1 Method Steps S2 Method Steps S3 Method Steps U0 voltage source U1 voltage source U2 voltage source UI Voltage Source UII voltage source UIII Voltage Source UIV voltage source

Claims

1. An apparatus (100) for analyzing and / or treating a sample (200) with a particle beam (112), comprising: a sample stage (120) for holding the sample (200); a supply unit (110) for supplying the particle beam (112), an aperture (114) for directing the particle beam (112) to a processing location (202) on the sample (200); and a shielding element (116) for shielding an electric field (E) generated by an electric charge (Q) accumulated on the sample (200); the shielding element (116) covers the opening (114), is embodied in a sheet-like manner, and comprises a conductive material; the shield element (116) comprises a convex section (117), the section being convex relative to the sample stage (120); and a supply unit (110) in which the convex section (117) has a through opening (118) for the particle beam (112) to pass through to the sample (200).

2. 2. The apparatus of claim 1, further comprising: a gas supply configured to supply a process gas to the processing position on the specimen through the through opening of the shield element.

3. 3. The apparatus according to claim 1, further comprising a gas supply (130) configured to supply a process gas (PG) into a gap, the gap being formed by the sample (200) disposed on the sample stage (120) and by the shield element (116).

4. 4. The apparatus of claim 2 or 3, wherein the gas feed (130) comprises a feed channel integrated into the shield element (116).

5. The apparatus of any one of claims 1 to 4, wherein the through opening (118) comprises a point at which the distance between the shield element (116) and the sample stage (120) is smallest.

6. The apparatus of any one of claims 1 to 5, wherein the shielding element (116) comprises a planar section (116A) from which the convex section (117) extends in the direction of the sample stage (120).

7. Device according to any one of the preceding claims, wherein said convex section (117) is embodied in a funnel-shaped manner, in particular with a circular cross section.

8. 8. The device according to claim 1, wherein the convex section (117) is embodied in such a way that a connecting straight line (LIN) connecting two points (P1, P2) on the surface of the convex section (117) of the shielding element (116) lies outside the shielding element (116) for any combination of two points (P1, P2) on the surface of the convex section (117) of the shielding element (116).

9. 9. The apparatus of claim 1, wherein the shielding element (116) comprises a layer of conductive material on a surface thereof, the layer having a thickness equal to or greater than a penetration depth of the particles of the particle beam (112) into the material.

10. The device according to any one of the preceding claims, wherein the shielding element (116) has exactly one through opening (118).

11. The device according to any one of the preceding claims, wherein the shielding element (116) has a plurality of through openings (118) separated from one another by webs (119).

12. 12. The apparatus of claim 11, wherein the through openings (118) each have a hexagonal cross section.

13. 13. The apparatus of claim 11 or 12, wherein the web (119) is shaped such that a sample stage-side cross-sectional area (118A) of each of the plurality of through-openings (118) in a first plane perpendicular to a surface normal (N) of the shield element (116) on the through-opening (118) is smaller than an opening-side cross-sectional area (118B) of the corresponding through-opening (118) in a second plane parallel to the first plane.

14. 14. The apparatus of claim 11, wherein one of the plurality of through openings (118) has a geometric feature that distinguishes the through opening (118) from further through openings (118).

15. The apparatus of any one of claims 11 to 14, wherein one of the plurality of through openings (118) comprises a point where the distance between the shield element (116) and the sample stage (120) is minimum, and further through openings (118) are arranged symmetrically with respect to the one through opening (118).

16. 16. The apparatus according to claim 1, comprising: a beam generating unit (111); and a beam guiding element (113) arranged between the beam generating unit (111) and the shielding element (116) and configured to guide the particle beam (112), wherein a voltage source (U1) is provided for applying a voltage between the shielding element (116) and the beam guiding element (113).

17. The shield element (116) is a retaining device (116 * ) and fixed to the supply unit (110) by the holding device (116) * ) and said shield element (116) are electrically insulated from each other, and said retaining device (116) * 17. The device according to claim 16, further comprising a further voltage source (U2) for applying a voltage between said first electrode (111) and said beam guiding element (113) and / or said shielding element (116).

18. The device according to any one of the preceding claims, wherein the shielding element (116) is held in an electrically insulating manner and comprises a detection unit (I1) for detecting the current flowing away from the shielding element (116).

19. 19. The device according to any one of claims 1 to 18, wherein the shielding element (116) comprises a plurality of sections (Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb) that are electrically insulated from one another and that define the through openings (118), and between in each case two oppositely arranged sections (Ia, Ib, IIa, IIb, IIIa, IIIb, IVa, IVb), a voltage can be applied by a corresponding voltage source (UI, UII, UII, UII, UIV).

20. 20. The device according to claim 1, wherein a plurality of shielding elements (116) are arranged side by side along the beam direction and cover the opening (114), and at least one of the plurality of shielding elements (116) is held in a displaceable manner to provide an opening with a settable aperture.

21. A method for analyzing and / or treating a sample (200) with a particle beam (112) by means of an apparatus (100) according to any one of claims 1 to 20, comprising: A step (S1) of placing the sample (200) on the sample stage (120); a step (S2) of supplying the particle beam (112); and (S3) emitting the particle beam (112) through the through opening (118) onto the processing location (202) on the sample (200).

Images