Method for processing a defect of a microlithographic photomask

Abstract

This invention discloses a method for processing defects (D) in a photomask (100), wherein a process gas is activated using a particle beam (802), wherein a control unit (828) is configured to control a deflection unit (816) having a control bandwidth (GF), wherein the deflection unit (816) for deflecting the particle beam (802) is configured to guide the particle beam (802) above the photomask (100), comprising the following steps: a) providing (step S1) an image (200') of at least a portion of the photomask (100); b) Based on the control bandwidth (GF), confirm the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) in the image (200'), wherein the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) contains a defect (D); and c) use the deflection unit (816) to provide the particle beam (802) at m pixels (410) of the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508), and activate the process gas to treat the defect (D).

Description

Technical Field

[0001] The present invention relates to a method for processing defects of a lithography mask, a computer program product, and a device. Prior Art

[0002] Lithography is used to generate microstructural components, such as integrated circuits. A lithography process is performed using a lithography apparatus that includes an illumination system and a projection system. In this case, an image of a mask (reticle) illuminated by the illumination system is projected onto a substrate (e.g., a silicon wafer) through the projection system. A photosensitive layer (photoresist) is coated and disposed in the image plane of the projection system to transfer the mask structure to the photosensitive coating of the substrate.

[0003] To obtain smaller structure sizes and thus increase the integration density of microstructural elements, light of very short wavelengths is increasingly used, such as, for example, deep ultraviolet (DUV) or extreme ultraviolet (EUV). The wavelength of DUV is, for example, 193 nm, and the wavelength of EUV is, for example, 13.5 nm.

[0004] In this case, the structure sizes of lithography masks are even from several nanometers to several hundreds of nanometers. The generation of such masks is very complex and thus expensive. In particular, this is because the mask must be defect-free, otherwise it is impossible to ensure that the structures generated on the silicon wafer through the mask can exhibit the desired functions. In particular, the quality of the structures on the mask can confirm the quality of the integrated circuits generated on the wafer through the mask.

[0005] For this reason, it is checked whether the lithography mask has defects, and the detected defects are repaired accordingly. Typical defects include structures that were not anticipated in advance, such as due to an unsuccessful execution of an etching process, or the presence of unanticipated structures, such as, for example, due to the etching process proceeding too fast or acting on the wrong location. These defects can be remedied by etching away redundant material in a targeted manner or depositing additional material in a targeted manner at the appropriate location; for example, this can be implemented in a very targeted manner through a focused electron beam induced process (FEBIP, "focused electron beam induced process").

[0006] Patent DE 10 2017 208 114 A1 describes a method for particle beam induced etching of a lithography mask. In this case, a particle beam (especially an electron beam) and an etching gas are provided at a position on the lithography mask to be etched. The particle beam activates a localized chemical reaction between the material of the lithography mask and the etching gas, as a result of which material is locally ablated from the lithography mask.

[0007] In this context, the problem to be solved by the present invention is to provide an improved method and an improved apparatus for processing defects of a lithography mask. Summary of the Invention

[0008] According to a first aspect, a method for processing defects of a lithography mask is provided, wherein a process gas is activated by a particle beam, and a control unit is arranged to control a deflection unit having a control bandwidth, and the deflection unit for deflecting the particle beam is configured to guide the particle beam above the mask, and the method includes the following steps: a) providing an image of at least a part of the mask; b) determining a repair shape in the image based on the control bandwidth, wherein the repair shape includes a defect; and c) using the deflection unit to provide a particle beam at m pixels of the repair shape and activating the process gas to process the defect.

[0009] Taking into account the control bandwidth when determining the repair shape allows considering the settling behavior of the particle beam on the target pixel. This results in an improved edge shape, in particular an improved edge steepness or an improved edge profile, especially when repairing defects.

[0010] The processing of the defect specifically includes etching the defect, within the scope of which material is locally ablated from the mask, or material is deposited on the mask in the defect area. For example, the proposed method allows better etching away of redundant structures in the defect area or better enhancing of defective structures in the defect area.

[0011] The repair shape includes a defect, that is, the repair shape includes a defect.

[0012] For example, an image of at least a part of the mask is recorded by a scanning electron microscope (SEM). For example, the image of at least a part of the mask has a spatial resolution on the order of several nanometers. A scanning probe microscope (SPM) (such as an atomic force microscope (AFM) or a scanning tunneling microscope (STM)) can also be used to record the image.

[0013] The method may particularly include the step of acquiring an image of at least a part of the mask by using a scanning electron microscope and / or a scanning probe microscope.

[0014] For example, a lithography mask is a mask used in EUV lithography equipment. In this case, EUV stands for "extreme ultraviolet" and represents that the wavelength of the working light is between 0.1 nm and 30 nm, especially 13.5 nm. In EUV lithography equipment, a beam shaping and illumination system is used to direct EUV radiation onto the mask (also referred to as "reticle"), which is especially in the form of a reflective optical element (reflective mask). The mask has a structure that is imaged in a reduced manner onto a wafer or the like through the projection system of the EUV lithography equipment.

[0015] For example, the lithography mask can also be a mask used in DUV lithography equipment. In this case, DUV stands for "deep ultraviolet" and represents that the working light wavelength is between 30 nm and 250 nm, especially 193 nm or 248 nm. In DUV lithography equipment, a beam shaping and illumination system is used to direct DUV radiation onto the mask, which is especially in the form of a transmissive optical element (transmissive mask). The mask has a structure that is imaged in a reduced manner onto a wafer or the like through the projection system of the DUV lithography equipment.

[0016] For example, the lithography mask includes a substrate and a structure formed on the substrate through a coating. For example, the mask is a transmissive mask, in which case the pattern to be imaged is implemented in the form of an absorption coating (i.e., opaque or partially opaque) on a transparent substrate. Alternatively, the mask can also be a reflective mask, for example, especially for EUV lithography. Binary or phase-shifting masks are considered in the embodiments.

[0017] For example, the substrate includes silicon dioxide (SiO₂), such as fused quartz. For example, the structured coating includes chromium, chromium compounds, tantalum compounds, and / or compounds made of silicon, nitrogen, oxygen, and / or molybdenum. The substrate and / or the coating can also include other materials.

[0018] In the case of a mask for EUV lithography equipment, the substrate can include an alternating sequence of molybdenum layers and silicon layers.

[0019] Using the proposed method, defects of the mask, especially defects of the structured coating of the mask, can be identified, located, and repaired. Specifically, the defects are coatings (such as absorption or reflection) of the mask that are wrongly applied on the substrate. The method can be used to enhance the coating at multiple positions lacking coating on the mask. Furthermore, the method can be used to remove the coating from multiple positions where the coating is wrongly applied on the mask.

[0020] To this end, the geometry of a defect is determined in the recorded image of at least a part of a photomask. For example, a two-dimensional geometry of the defect is determined. The determined geometry of the defect is hereinafter referred to as the so-called repair shape.

[0021] m pixels are defined in the repair shape for performing particle beam induced processing on the repair shape. During this method, the particle beam is guided to each of the m pixels of the repair shape. Specifically, the maximum value of the intensity of the electron beam is guided to the center of each of the m pixels. In other words, the m pixels of the repair shape represent a grating of the repair shape for particle beam induced processing, particularly a two-dimensional grating. For example, the m pixels of the repair shape correspond to the particle beam incident area during particle beam induced processing of the defect. For example, the pixel size is selected in such a way that, due to the Gaussian intensity distribution of the electron beam, the intensity distribution of the electron beam guided at the pixel center drops to a predetermined intensity at the edge of the pixel. The predetermined intensity may correspond to dropping to half of the maximum intensity of the electron beam or dropping to any other part of the maximum intensity of the electron beam. For example, the pixel size and / or the full width at half maximum of the electron beam are in the sub-nanometer range or on the order of several nanometers.

[0022] For example, the process gas is a precursor gas and / or an etching gas. For example, the process gas can be a mixture of a plurality of gas components, i.e., a process gas mixture. For example, the process gas can be a mixture of a plurality of gas components, where each gas component has only a specific molecular type.

[0023] Specifically, alkyl compounds of main group elements, metals or transition elements can be considered as precursor gases suitable for depositing or growing elevated structures. Examples thereof are (cyclopentadienyl)trimethylplatinum (CpPtMe3, Me = CH4), (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe3), tetramethyltin (SnMe4), trimethylgallium (GaMe3), ferrocene (Cp2Fe), diarylchromium (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), dodecacarbonyltriruthenium (Ru3(CO)12), iron pentacarbonyl (Fe(CO)5), and / or alkoxide compounds of main group elements, metals or transition elements, such as tetraethyl orthosilicate (Si(OC2H5)4), titanium tetraisopropoxide (Ti(OC3H7)4), and / or halides 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), and / or complexes containing main group elements, metals or transition elements, such as copper bis(hexafluoroacetylacetonate) (Cu(C5F6HO2)2), dimethylgold trifluoroacetylacetonate (Me2Au(C5F3H4O2)), and / or organic compounds, such as carbon monoxide (CO), carbon dioxide (CO2), aliphatic and / or aromatic hydrocarbons, etc.

[0024] For example, the etching gas can include: xenon difluoride (XeF2), xenon dichloride (XeCl2), xenon tetrachloride (XeCl4), steam (H2O), heavy water (D2O), 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. Other etching gases for etching one or more deposited test structures are described in detail in the applicant's U.S. Patent Application No. 13 / 0103281.

[0025] The process gas may include additional gases, for example, oxidation gases such as hydrogen peroxide (H2O2), nitrous oxide (N2O), nitrogen oxides (NO), nitrogen dioxide (NO2), nitric acid (HNO3) and other oxygen-containing gases; and / or halides such as chlorine (Cl2), hydrogen chloride (HCl), hydrogen fluoride (HF), iodine (I2), hydrogen iodide (HI), bromine (Br2), hydrogen bromide (HBr), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), phosphorus trifluoride (PF3) and other halogen-containing gases; and / or reducing gases such as hydrogen gas (H2), ammonia gas (NH3), methane (CH4) and other hydrogen-containing gases. These additional gases can be used, for example, in the etching process, as a buffer gas, as a passivation medium, etc.

[0026] For example, an activated particle beam is provided by a device, which may include: a particle beam source for generating a particle beam; a particle beam guiding device (such as a scanning unit) configured to guide the particle beam to the repaired shape, a plurality of repaired shapes or the relative pixels of the relative repaired sub-shapes; a particle beam shaping device (such as an electron or beam optical element) configured to shape (especially focus) the particle beam; at least one storage container configured to store the process gas or at least one gaseous component of the process gas; at least one gas supply device configured to supply the process gas, or to deliver at least one gas component of the process gas to the relative pixels of the repaired shape, a plurality of repaired shapes or the relative repaired sub-shapes at a predetermined gas volume flow rate.

[0027] The activated particle beam includes, for example, an electron beam, an ion beam and / or a laser beam.

[0028] For example, an electron beam is provided by a modified scanning electron microscope. For example, the same modified scanning electron microscope that provides the activated electron beam is used to record an image of at least a part of the photomask.

[0029] The activated particle beam, in particular, activates the localized chemical reaction between the photomask material and the process gas, which results in the local deposition of the material on the photomask from the gas phase or the transformation of the material of the photomask into the gas phase.

[0030] The activated particle beam is continuously provided at each pixel of the repaired shape, a plurality of repaired shapes or the relative repaired sub-shapes, for example, through a particle beam guiding device (especially a deflection unit). In step c) of the method, the activated particle beam remains at each pixel for a predetermined residence time. For example, the residence time is 100 ns.

[0031] The repair shape may include all or part of the defect. The repair shape may be: kidney-shaped, U-shaped or annular. In the current context, "repair shape" may also refer to a repair sub-shape, provided that there are no contrary provisions.

[0032] For example, the numbers "m" and / or "n" (see below) are greater than 100, 1000, 10000, 100000 or 1000000 in each case.

[0033] According to one embodiment, the control bandwidth is confirmed or provided before step a), in particular before or when the particle beam column is put into operation in order to carry out steps a) to c), where preferably, the confirmed or provided control bandwidth or a value derived therefrom is stored in a data memory before step b) and used in step b).

[0034] In particular, the control bandwidth or a value derived therefrom can be stored in a computer program that operates within the scope of the above method.

[0035] According to a further embodiment, step b) includes: b1) Subdividing the repair shape containing the defect into k repair sub-shapes based on the control bandwidth and selecting one of the k repair sub-shapes; and / or b2) Subdividing the repair shape containing the defect into the k repair sub-shapes and selecting one of the k repair sub-shapes, where the selection is carried out based on the dry control bandwidth, where step c) includes: Providing a particle beam at m pixels of the selected k repair sub-shapes using the deflection unit and activating a process gas to process the defect.

[0036] Thus, the control bandwidth can be taken into account during the subdivision of the repair shape or only during the selection of the opposing repair sub-shape, in particular when determining the order of the repair sub-shapes that the particle beam sweeps over continuously in time. According to a variant, both the subdivision and the selection can be carried out based on the control bandwidth. "k" can be greater than or equal to 2, 10 or 100.

[0037] According to a further embodiment, the confirmation according to step b) or the subdivision according to step b1), and / or the selection according to step b2) is carried out based on the interval or jump width between two repair shapes or between two of the k repair sub-shapes.

[0038] The greater the pitch or jump width, the longer the time usually required for the particle beam to reach a stable state again. Therefore, it is particularly advantageous to link this information to the control bandwidth.

[0039] According to a further embodiment, step c) includes: Using the deflection unit to provide a particle beam at m pixels of the first repair shape or the first of the k repair sub-shapes, and activating a process gas to process the defect, Using the deflection unit to provide a particle beam at n pixels of the second repair shape or the second of the k repair sub-shapes, and activating a process gas to process the defect.

[0040] Specifically, before switching to the next repair shape, each of the k repair sub-shapes can be scanned by the particle beam or raster scanned more than 100 or more than 1000 times, and then scanned more than 100 or more than 1000 times again when switching to the next repair sub-shape. The particle beam can be deactivated or raster scanned between multiple repetitions to allow the process gas to flow into the opposite repair sub-shape.

[0041] According to a further embodiment, the first pixel and / or the last pixel among the n or m pixels are selected in a random manner.

[0042] This avoids unnecessary patterns on the photomask.

[0043] According to a further embodiment, each of the k repair sub-shapes is formed without interruption along the scanning direction of the particle beam.

[0044] Therefore, it can be scanned quickly and there is no jump effect (settling of the particle beam).

[0045] According to a further embodiment, the scan line method is used in step b1) or b2).

[0046] This mathematical method allows the repair shape to be simply and effectively divided into a plurality of repair sub-shapes, each of which is convex and / or at least implemented without interruption along the scanning direction (that is, without cuts). Therefore, the particle beam does not need to overcome gaps, cuts, etc. This can avoid jump or settling effects.

[0047] According to a further embodiment, the repair shape includes a cut, and its size is between 5 nm and less than 10 μm.

[0048] According to a further embodiment, the distance between two pixels within the repair shape or the corresponding one of the k repair sub-shapes is less than 40, 20 or 5 nm.

[0049] According to a further embodiment, the deflection unit includes a multipole, in particular an octupole, for beam deflection.

[0050] Other members for beam deflection (such as capacitor plates or magnetic coils) can be used instead of the multipole or octupole.

[0051] According to a further embodiment, in step c), the particle beam moves in a straight line and / or moves along parallel lines or lines perpendicular thereto.

[0052] According to a further embodiment, in step c), the particle beam moves parallel to the longest edge and / or to one of the k repair sub-shapes.

[0053] Thus, an undesired jump of the particle beam can be avoided, or an effective scanning of the particle beam over the repair shape or the repair sub-shape can be obtained thereby.

[0054] According to a further embodiment, in step b), a first repair shape containing a defect and a second repair shape are identified, wherein the second repair shape is at least partially located within the first repair shape.

[0055] Advantageously, a so-called bias effect can be obtained thereby; this can also take into account the deposition behavior of the particle beam at the target position (target pixel).

[0056] According to a further embodiment, the contour of the second repair shape is partially recessed relative to the contour of the first repair shape.

[0057] According to a further embodiment, the second repair shape partially has the same contour as the first repair shape.

[0058] Depending on the jump pixel or target pixel of the particle beam, it may or may not be necessary to offset the contour relative to the first repair shape, depending on the circumstances.

[0059] According to a further embodiment, when the first repair shape and the second repair shape overlap between two adjacent contours of the first repair shape and the second repair shape, one or more pixels are positioned along a straight line intersecting the two adjacent contours.

[0060] According to a second aspect, there is provided a computer program product. The computer program product includes a plurality of instructions that, when executed by a device to process a mask defect of a lithography device, cause the device to perform the above method steps.

[0061] The computer program product (such as a computer program medium) can be provided or supplied, for example, in the form of a storage medium such as a memory card, a USB stick, a CD-ROM, a DVD, or a file downloadable from a server on the network. For example, in a wireless communication network, this can be implemented by transmitting an appropriate file using the computer program product or computer program component.

[0062] According to a third aspect, there is provided a device for processing a defect of a lithography mask. The device includes: A process gas supply device for supplying a process gas; A particle source for providing a particle beam; A deflection unit for deflecting the particle beam to provide the particle beam at m pixels of the repair shape and activate the process gas; A control unit for controlling the deflection unit having a control bandwidth; A detector unit for providing an image of at least a part of the mask; and A confirmation unit for confirming the repair shape in the image based on the control bandwidth, wherein the repair shape includes a defect.

[0063] Each of the above-mentioned and the following units (such as a computing device, a control unit, or a confirmation unit) can be implemented in hardware and / or software. In the case of implementation in hardware, the corresponding unit can be implemented as a device or a part of a device, such as a computer or a microprocessor. For example, the device can include a central processing unit (CPU), a graphics processing unit (GPU), a programmable hardware logic (such as a field programmable gate array, FPGA), an application specific integrated circuit (ASIC), etc. Furthermore, the one or more units can be implemented entirely in a single hardware device and can share a memory, a plurality of interfaces, etc. These units can also be implemented in separate hardware components.

[0064] In this case, "one" is not necessarily to be understood as a limitation to exactly one element. Instead, a plurality of elements, such as two, three or more, may also be provided. Nor should any other number used herein be understood as limiting the exact number of elements. Instead, there may be upward and downward deviations of the numerical value, unless otherwise stated.

[0065] Further possible implementations of the present invention also cover combinations of features or embodiments not explicitly mentioned that are described above or below with respect to the exemplary embodiments. In such cases, the person skilled in the art will also add individual aspects as improvements or supplements to the relative basic form of the present invention. Brief Description of the Drawings

[0066] Further advantageous configurations and aspects of the present invention are the subject matter of the dependent claims and the subject matter of the following description of the exemplary embodiments of the present invention. The present invention will be described in detail below with reference to the preferred embodiments of the accompanying drawings. FIG. 1 schematically shows details of a lithographic mask having defects in a structured coating according to an embodiment; FIG. 2 shows details of a mask that first has a perfect structure and then has defects according to an embodiment; FIG. 3 shows an enlarged view of the defect in FIG. 2; FIG. 4 shows a plurality of three exemplary scanning methods; FIG. 5 schematically shows a repair shape of a defect having two repair sub-shapes; FIG. 6 shows the position of an electron beam as a function of time in an exemplary embodiment; FIG. 7 compares two edge geometries established using different control bandwidths; FIG. 8 shows an apparatus for processing defects of a mask according to an exemplary embodiment; FIG. 9 schematically shows the functional interaction of several components in FIG. 8; FIG. 9A shows the amplitude of a control signal as a function of frequency according to an exemplary embodiment; FIG. 10 shows an exemplary embodiment of a method in a flowchart; FIGS. 11 and 12 show annular repair shapes according to various exemplary embodiments; FIG. 13 shows repair sub-shapes having different spacings from each other along the scanning direction according to an exemplary embodiment; FIG. 14 shows repair sub-shapes configured in a two-dimensional grid according to an exemplary embodiment; FIG. 15 shows that the repair shape in FIG. 5 is subdivided into five repair sub-shapes according to an exemplary embodiment; Figures 16 to 20 show repair shapes with different geometries according to various exemplary embodiments; Figure 21 shows a view of Figure 1 according to an exemplary embodiment, in which the scanning direction for defect repair is appropriately selected; Figure 22 shows a view of Figure 5, in which scanning is performed according to a method with a bias effect; Figure 23 shows a concave profile in a repair sub-shape; Figure 24 shows an enlarged view of Figure 23; and Figure 25 shows two concave profiles in a repair sub-shape. Unless otherwise specified, elements that are the same or have the same function in the drawings have the same reference numerals. Furthermore, it should be noted that the illustrations in the drawings are not necessarily drawn to scale. Embodiments

[0067] Figure 1 schematically shows details of a lithography mask 100. In the illustrated example, the mask 100 is a transmissive lithography mask 100. The mask 100 includes a substrate 102. The substrate 102 is optically transparent, especially at the wavelength at which the mask 100 is exposed. For example, the material of the substrate 100 includes fused quartz.

[0068] A structured coating 104 (pattern element 104) has been applied to the substrate 102. Specifically, the coating 104 is a coating made of an absorbing material. For example, the material of the coating 104 includes a chromium layer. For example, the thickness of the coating 104 ranges from 50 nm to 100 nm. The structural dimension B of the structure formed by the coating 104 on the substrate 102 of the mask 100 can be different at various positions of the mask 100. For example, in Figure 1, the width B of the region is drawn as the structural dimension. For example, the structural dimension B ranges from 20 to 200 nm. The structural dimension B can also be greater than 200 nm, for example, on the micron scale.

[0069] In other examples, other materials in addition to the materials mentioned can also be used for the substrate and the coating. Furthermore, the mask 100 can also be a reflective mask instead of a transmissive mask. In this case, a reflective layer is applied instead of an absorbing layer 104.

[0070] Sometimes, during the manufacturing process of a photomask, a defect D may occur, for example because the etching process does not operate exactly as expected. In FIG. 1, this defect D is represented by the shaded line. This is excess material because even if two coating regions 104 adjacent to each other in the template of the photomask 100 are envisioned as separate, the coating 104 has not been removed from this region. It can also be said that the defect D forms a connector. In this case, the size of the defect D corresponds to the structural dimension B. Other defects smaller than the structural dimension B (for example in the range of 5 to 20 nm) are also known. In order to ensure that the structures generated on a wafer using the photomask have the desired shape and result in semiconductor components generated in this way meeting the desired functionality, it is therefore necessary to repair defects such as the defect D shown in FIG. 1 or other defects. In this example, it is necessary to remove the connector in a targeted manner, for example by particle beam induced etching.

[0071] FIGS. 2 to 4 are used to schematically illustrate a possible procedure for repairing the defect D shown in FIG. 2. 200 on the left side of FIG. 2 represents a "perfect" region. That is to say, the coating 104 or the substrate 102 corresponds to the target specifications in this region. Subsequently, the perfect image details 200 are copied and placed above the defect D, as indicated by the reference numeral 200'. FIG. 3 shows an enlarged view of the defect D. In the present exemplary embodiment, the defect D is formed by protruding excess material. Through the superposition of the perfect material region 200, the material to be removed becomes clear.

[0072] In the case of electron beam based photomask repair, the region D is now scanned thousands of times with an electron beam to remove the defect. Here, whether this involves so-called transparent defects or opaque defects is initially immaterial.

[0073] FIG. 4 shows various scan variants for moving the electron beam above the defect D, thereby relatively etching away the coating 104 (or in other variants depositing material from the process gas for repair purposes) under activation of the process gas. For example, the pattern shown in FIG. 4 is repeatedly traversed or raster scanned 100 to 1000000 times until the corresponding defect is ablated or deposited.

[0074] In FIG. 4, the reference numeral 400 represents a bent x scan, the reference numeral 402 represents a bent y scan, and the reference numeral 404 represents a raster scan. Starting from the bent x scan 400 in the center of FIG. 4, where the solid line 406 (hereinafter referred to as the "scan line") represents a column of pixels 410 of a continuous scan or raster scan. The particle beam is offset in the y direction at the end of the corresponding scan line 406 (hereinafter referred to as a "jump") 408. Then, before scheduling another jump 408, the particle beam moves in the negative x direction in a manner parallel to the previous scan line 406.

[0075] The scanning in the x direction can equally well be carried out easily in the y direction. Thus, the pixels here are scanned in the y direction, while the jumps are carried out in the x direction. This is shown on the right side of FIG. 4 (curved y-scan 402). The left side of FIG. 4 shows a so-called raster scan 404. In this case, there is a diagonal return jump at the end of the corresponding scan line 406, so that the starting point returns to x = 0 (origin O).

[0076] The pixel 410 corresponds to a plurality of image points in the image detail 200' of FIG. 2. Each pixel 410 corresponds to a position on the mask 100. At this point, the electron beam is incident on the process gas, thereby triggering an etching or deposition process at this position. The pitch of the pixels is, for example, less than 40, 20 or 5 nm. In FIG. 4, the pitch between two adjacent pixels 410 is shown by way of example and is denoted therein by A.

[0077] In the region of the scan line 406, the electron beam moves at a defined speed, and in this process, the individual pixels 410 are addressed, that is, the electron beam dwells on the relative pixel 410 for a defined time (the "dwell time"). The electron beam moves as fast as possible in the region of the relative jump 408. For example, the dwell time can be between 10 and 500 nanoseconds. At the end of the dwell time, the electron beam moves to the next pixel, sweeping through the intermediate region between two adjacent pixels 410 within the pitch A. The electron beam is not deactivated in the intermediate region. However, since the exposure time in the intermediate region is very short, the electron beam does not produce any significant effect. Therefore, it is not deactivated at the first pixel at the end of the dwell time, moves to the next pixel and is reactivated there.

[0078] The same applies to the jump 408. For example, the reference numeral 410' is used to denote the last pixel of the scan line 406. The reference numeral 410'' is used to denote the first pixel of the next scan line 406. The electron beam moves as fast as possible between the pixels 410' and 410''. For example, it is not deactivated at the end of the dwell time at the pixel 410' and reactivated at the next pixel 410''.

[0079] The jump between two adjacent pixels 410 is characterized by maintaining the scanning direction (in this case, the positive x direction). In contrast, the jump between pixels 410, 410' in different scan lines 406 is characterized by a change from one scanning direction (in this case, the positive x direction) to another scanning direction, optionally the opposite scanning direction (in this case, the negative x direction). Between two repair shapes 500, 502 (see below), there is a jump from one repair (sub) shape to another repair (sub) shape.

[0080] Figure 5 shows a defect D and a designated repair shape 108, which is confirmed from the image details 200'. Using a computer device and an appropriate algorithm, the repair shape 108 is decomposed into, for example, two repair sub - shapes (parts) 500, 502. The repair sub - shapes (for example, in this case, a rectangle 500 and a rectangular ring 502) are spaced apart from each other in the scanning direction x. Thus, this generates a first scan line 406 within the repair sub - region 500, followed by a jump 504, and then another scan line 406' within the repair sub - shape 502. For example, since a curved x - scan 400 is performed here, the electron beam is deflected in the y - direction at the end of the scan line 406', thereby causing a jump 408. Subsequently, the electron beam moves back in the direction of the origin O parallel to the scan line 406.

[0081] The repair sub - shape 502 contains a notch 506. This is the area surrounded by the ring 502. For example, the width d of the notch 506 along the scanning direction x can be at least 500 nm and less than 10 μm. Thus, there is a further jump 508 of the electron beam within the repair shape 502.

[0082] Figure 6 shows a graph with the horizontal axis as time t and the vertical axis as the jump width P. As described above, the electron beam moves as fast as possible in the regions of jumps 408, 504, 506. For this purpose, the electron beam is initially strongly accelerated from position P0 (the first pixel) and then strongly decelerated to position P1 (the next pixel). In the case of an electron beam column, the electron beam is deflected from position P0 to position P1 through a deflection unit (shown in Figure 8).

[0083] For example, the deflection unit is an octopole (or other multipole) at the lower end of the electron beam column. The octopole rod contains a plurality of coils or electrodes that generate an electric or magnetic field for beam deflection purposes. In other embodiments, one or more capacitors (especially capacitor plates) can be used to replace the octopole. The deflection unit is controlled by a control unit (as shown in FIG. 8). Since the control unit has a limited control bandwidth, the electron beam must first be stabilized at the end of the movement (settling curve 600), i.e., position P1.

[0084] If the jump width is shorter, as shown by point P2 in FIG. 6, then the amplitude AP of the settling curve 600’ is smaller than the amplitude AP of the settling curve 600. This initially means that there is a different dose distribution (electron dose) at the target points P1 or P2 of the jumps 408, 504, 506 relative to the initial point P0. It has also been found that for the same control bandwidth, in the case of a smaller jump width, the electron dose after the jump can be better concentrated at a single point (see position P2). The same applies if the control bandwidth is increased and the jump width remains unchanged.

[0085] The left side of FIG. 7 shows a plan view of partial details of the mask 100. In the area shown, the mask 100 includes two coatings 104 that are spaced apart from each other by an exposed area 102 in which the substrate is visible. In an exemplary embodiment, the electron beam jumps from point P0 to point P1. The dwell time at point P0 (corresponding to the last pixel of a scan line not shown) is, for example, 20 ns, just as at point P1 (the first pixel of a scan line not shown). The control bandwidth is 5 MHz.

[0086] The edge 702 of the structure 104 becomes blurred due to the settling curve 600 (see FIG. 6). The relatively flat increase in the dose distribution has a negative impact on the edge steepness (so-called sidewall angle) of the edge repair. There is no problem with the settling behavior at the jump points, resulting in sharp edges here; this also appears in the image on the left side of FIG. 7.

[0087] The mask 100’ is shown on the right side of FIG. 7. In this case, the structure corresponds to the structure schematically shown on the left side. However, the electron beam column used to process the mask 100’ has a higher control bandwidth, specifically 100 MHz. Therefore, the amplitude AP of the settling curve (see 600’ in FIG. 6) is smaller. Compared to the illustration on the left side, this results in a greater edge steepness. Therefore, the edge 702’ has a sharp embodiment in the illustration on the right side of FIG. 7.

[0088] Figure 8 shows an apparatus 800 for performing particle beam induced treatment on a defect D of a lithography mask 100, such as the defect D of the mask 100 in FIGS. 1, 2, 3, 5, and 7. For example, the apparatus 800 is a repair tool for the mask 100 of a DUV or EUV lithography apparatus.

[0089] FIG. 8 schematically shows a cross-section of several components of the apparatus 800, which can be used for particle beam induced repair of a defect D of the mask 100, in this case etching. Furthermore, the apparatus 800 can also be used for imaging the mask, particularly the structured coating 104 and the defect D of the mask 100, before, during, and after the repair process is implemented.

[0090] The apparatus 800 shown in FIG. 8 represents a modified scanning electron microscope 800. In this case, a particle beam in the form of an electron beam 802 is used to repair the defect D. Using the electron beam 802 as an activation particle beam has the advantage that the electron beam 802 basically does not damage or only slightly damages the mask 100, particularly its substrate 102.

[0091] In multiple embodiments, a laser beam that activates a local particle beam induced repair process of the mask 100 can be used to replace the electron beam 802, or in addition to the electron beam 802 (not shown in FIG. 8) in the embodiment. In addition, an ion beam, an atomic beam, and / or a molecular beam can be used to activate a localized chemical reaction (not shown in FIG. 8), instead of using an electron beam and / or a laser beam.

[0092] The apparatus 800 is mainly arranged in a vacuum housing 804, which is maintained at a certain gas pressure by a vacuum pump 806.

[0093] The mask 100 to be processed is arranged on a sample stage 808. For example, the sample stage 808 is arranged to set the position of the mask 100 in three spatial directions and three rotation axes with a precision of several nanometers.

[0094] The apparatus 800 includes an electron column 810. The electron column 810 includes an electron source 812 for providing the activation electron beam 802. Furthermore, the electron column 810 includes electron or beam optical elements 814. The electron source 812 generates the electron beam 802, and the electron or beam optical device 814 focuses the electron beam 802 and guides the electron beam to the mask 100 at the output of the electron column 810. The electron column 810 further includes a deflection unit 816 (scanning unit 816), which is configured to guide (i.e., raster scan or scan) the electron beam 802 on the surface of the mask 100.

[0095] The apparatus 800 further includes a detector 818 for detecting secondary electrons and / or backscattered electrons generated by the incident electron beam 802 at the mask 800. For example, as shown in the figure, the detector 818 is arranged in an annular manner around the electron beam 802 in the electron column 810. In addition to and / or as an alternative to the detector 818, the apparatus 800 may further include other detectors (not shown in FIG. 8) for detecting secondary electrons and / or backscattered electrons.

[0096] Furthermore, the apparatus 800 may include one or more scanning probe microscopes, such as a scanning force microscope, which can be used to analyze the defects D of the mask 100 (not shown in FIG. 8).

[0097]

[0098] The apparatus 800 further includes a gas supply device 820 for supplying a process gas to the surface of the mask 100. For example, the gas supply device 820 includes a valve 822 and a gas pipeline 824. By guiding the electron beam 802 to a position on the surface of the mask 100 through the electron column 810, an electron beam induced process (EBIP) can be carried out in combination with the process gas supplied from the outside by the gas supply device 820, which is through the valve 222 and the gas pipeline 824. Specifically, the process includes deposition and / or etching of materials.

[0099] Specifically, the computing device 826 controls the supply of the electron beam 802 by controlling the electron column 810. Specifically, the control unit 828 controls the raster scanning of the electron beam 802 on the surface of the mask 100 by controlling the deflection unit 816. Furthermore, the computing device 826 controls the supply of the process gas by controlling the gas supply device 820.

[0100] Furthermore, the computing device 826 receives measurement data from the detector 818 and / or other detectors of the apparatus 800, and creates an image based on the measurement data, and the image can be displayed on a monitor (not shown). Furthermore, the image created based on the measurement data can be stored in the memory unit 832 of the computing device 826.

[0101] ​To inspect the mask 100, in particular the structured coating 104 of the mask 100, the device 800 is specifically configured to capture an image of the mask 100 (Figure 1), or an image 200' of the details of the mask 100 from measurement data of the detector 818 of the device 800 and / or other detectors. For example, the spatial resolution of the image 300 is on the order of several nanometers.

[0102] The computing device 826 (in particular the verification unit 830) is configured to identify a defect D (Figure 1) in the recorded image 200', locate the defect and confirm the geometric shape (repair shape 108) of the defect D. For example, the confirmed repair shape 108 is a two-dimensional geometric shape.

[0103] The computing device 826 (in particular the verification unit 830) is configured to arrange the repair shape 108 in a grid containing m pixels 410 (see Figure 4). For example, the repair shape 108 contains one million pixels 304 (m = 1000000). For example, the size of the pixel 304 is 1.5 nm × 1.5 nm. During the repair process, the electron beam 802 is guided through the deflection unit 816 multiple times to the center of each pixel 410. Specifically, during the process of this method, the intensity maximum of the Gaussian intensity distribution of the electron beam 802 is guided to the center of each pixel 410 multiple times.

[0104] Figure 9 schematically shows some components in Figure 8. The control unit 828 generates a control signal XS, which is used to control the deflection unit 816. Figure 9A shows the amplitude AXS of the control signal XS as a function of the frequency f. The control unit 828 can be considered a low-pass filter. The low-pass filter passes signals at frequencies up to the limit frequency GF, which is called the control bandwidth in this example, with little change in the signal. On the contrary, the output signal XS of the control unit 828 attenuates significantly above the limit frequency GF. Therefore, relatively speaking, the control signal XS consists of frequency components below the control bandwidth GF. The control signal XS is preferably analog. The control unit 828 itself can have an analog or digital embodiment. Specifically, it receives a digital signal from the verification unit 830, and this digital signal is converted into an analog signal within the control unit 828.

[0105] For example, the function depicted in Figure 9A can be confirmed by examining the frequency components of the control signal XS. For example, the control bandwidth GF can be defined as the frequency f, as illustrated in Figure 9A, where the amplitude AXS drops below 80% of the maximum amplitude AXS. The control bandwidth GF is provided to the verification unit 830.

[0106] In a variant, after calibration of the device 800 or during operation of the device 800, the control bandwidth GF is read from the control unit 828, that is, when raster scanning the pixels 410. Accordingly, the confirmation unit 830 can respond to changes in the control bandwidth.

[0107] In another variant, the control signal XS is measured after the device 800 has been put into operation and calibrated, and the control bandwidth GF is confirmed, more specifically determined, based on the measured data. The control bandwidth GF defined in this way is, for example, stored in the data memory 832 (see FIG. 8). Specifically, the control bandwidth GF can be stored as part of a computer program executed on the computing device 826. Specifically, the computer program can be part of the confirmation unit 830. In the confirmation unit 830, the control bandwidth GF is used to confirm the repair shape 108 with a defect D based on the control bandwidth.

[0108] Generally speaking, the corresponding method is as shown in FIG. 10. In step S1, the device 800 is used to record and thereby provide an image of at least a part of the photomask 100. In particular, the recording is implemented using the detector unit 818.

[0109] In step S2, the repair shape 108 is confirmed in the image 200’, specifically, the repair shape 108 is confirmed in a manner depending on the control bandwidth GF. The repair shape 108 includes the defect D, more precisely at least partially or entirely includes the defect D. How to specifically determine the repair shape 108 will be explained in detail below. Importantly, the confirmation does not need to be implemented in a way that directly depends on the control bandwidth GF. In particular, a value derived from the control bandwidth GF can also be used. As described for the control bandwidth GF, this value can be read from the control unit 828 and / or provided in the memory unit 832, optionally as part of the above computer program. This situation of indirectly using the control bandwidth GF is also included in the current situation.

[0110] In step S3, the particle beam 802 is provided at m pixels 410 of the repair shape 108 using the deflection unit 816, and the particle beam 802 activates the process gas at that location, thereby processing, more specifically etching or depositing, the resulting defect.

[0111] Step S2 can be designed such that one or more of its implementation variants S2-1 to S2-3 are implemented, which are depicted on the left side of FIG. 10. In this case, one of the variants S2-1 to S2-3 can be implemented in the device 800, or a plurality of variants can be implemented, and depending on the application, one of the variants S2-2 to S2-3 can be selectively selected automatically.

[0112] The variants S2-1 and S2-2 are explained in detail below specifically based on FIGS. 13 to 15. Regarding variant S2-3, refer to FIGS. 22 to 25.

[0113] A possible implementation of method step S2-1 is explained based on FIGS. 11 and 12. FIGS. 11 and 12 each show an annular defect D or corresponding repair shapes 108, 108'. They each include a notch 1100 and 1200, in which no pixels should be scanned, or the area remains unaffected by the treatment of the electron beam 802. The diameter of notch 1100 is denoted as d1, and the diameter of notch 1200 is denoted as d2. For diameter d1, i.e., the repair shape 108, the confirmation unit 830 now confirms that the corresponding skip width will be too large and this will result in an unacceptable edge not being obtained. This is taking into account the confirmed control bandwidth GF. Therefore, it divides the repair shape 108 into two semi-circular repair shapes 1102, 1104, and then scans these two semi-circular repair shapes through separate curved scans 400, 400'.

[0114] In contrast, in view of the control bandwidth GF and the diameter d2 which is relatively smaller than diameter d1, the confirmation unit 830 evaluates the defect D or the repair shape 108' such that the repair shape 108' can be scanned as a whole, that is, using a curved x-scan. Therefore, the scan line 406 has a skip 1202 in the area of notch 1200.

[0115] For the purpose of explaining step S2-2, FIG. 13 shows the repair shape 108 of the defect D, which is divided into, for example, three repair sub-shapes 1300, 1302, and 1304 with the help of the confirmation unit 830. For example, the confirmation unit 830 can make a decision that considering the control bandwidth GF, the skip width 1306 in the scanning direction x is still acceptable. Therefore, a scan line 406 is used to scan both the repair shape 1300 and the repair shape 1302 covering part 1308 in the y direction (i.e., transverse to the scanning direction x).

[0116] This is not the case for the repair shape 1304; in this case, the confirmation unit 830 determines that considering the control bandwidth GF, the skip width 1310 will be too large. Therefore, the repair shape 1304 is scanned separately only after or before scanning the repair shapes 1300, 1302.

[0117] Figure 14 shows a rectangular defect D or a rectangular repair shape 108. For example, the rectangular repair shape is subdivided again into rectangular repair shapes, which form a grid in the x and y directions. For example, some of the repair shapes have been labeled 1400 to 1410. The subdivision of the repair shapes 1400 to 1410, that is, the dimensions of the corresponding rectangles, can be determined, for example, by maintaining the process gas atmosphere at a level sufficient for etching or deposition during the raster scan of the pixels (not shown) relative to the rectangles 1400 to 1410. If the repair shape is too large, this cannot always be ensured.

[0118] In each case, the repair shapes 1400 to 1410 are scanned independently, so that each repair shape is assigned a bending scan 400. For the opposite repair shapes 1400 to 1410, the bending scan 400 can be repeated thousands of times, for example until the corresponding next repair shape 1400 to 1410 changes. This change is shown in Figure 14 by the jumps 1412, 1414, 1416, and 1418. These jumps or the decision about jumping to the next repair shape are determined by the confirmation unit 830 taking into account the control bandwidth GF. Given the control bandwidth GF, it may be found that the individual jumps here are too far for generating sufficient edge steepness. For example, the control unit 830 may determine that the jumps 1414 or 1416 are too far, but the jumps 1412 and 1418 are acceptable. For example, as shown by the jump 1414, it may also be decided here that jumping to the pixel 1420 would be too far, but jumping to the pixel 1422 is still acceptable.

[0119] The confirmation unit 830 can be further configured to select a jump pixel (here, the pixel 1424 is used for illustration), and / or to randomly select a target pixel 1422 from the pixels included in the repair shape 1400 or 1406. This can prevent repeating (unwanted) patterns, which are determined by not changing the jumps and target positions that appear on the mask 100.

[0120] Figure 15 shows an exemplary embodiment having a repair shape 108 corresponding to Figure 5. However, here it has been implemented by subdividing into five repair sub-shapes 1500, 1502, 1504, 1506, 1508. This is performed in such a way that admissible jumps can always be executed with the known control bandwidth GF.

[0121] Otherwise, it should be observed that by changing the scan direction from x to y, it has been possible to find a repair shape 108 that is acceptable in view of the control bandwidth GF. This makes no difference in the case where the cuts 1510 have the same dimensions in the x-direction and the y-direction. However, if the width of the cut 1510 is larger in the x-direction and the depth is narrower in the y-direction, changing the scan direction from x to y will result in no longer having an admissible jump width.

[0122] Figures 16 to 20 show various options for subdividing the repair shape 108 such that an admissible jump width is observed taking into account the control bandwidth GF, or jumps are completely avoided.

[0123] For example, the annular segment 108 in Figure 16 is subdivided by the confirmation unit 830 into two semi-annular segments.

[0124] The kidney-shaped 108 in Figure 17 is also subdivided by the confirmation unit 830 into two admissible repair shapes.

[0125] For the serrated edge region 1800 of the repair shape 108 in Figure 18, the confirmation unit 830 determines that the repair shape can be scanned without jumps by bending the x-scan.

[0126] Regarding Figure 19, the confirmation unit 830 subdivides the repair shape 108 into two repair shapes, specifically into two polygons, in this case a quadrilateral 1900 and a pentagon 1902.

[0127] The repair shape 108 in Figure 20 (part of which is also kidney-shaped) is subdivided into five repair shapes so that it is possible to pass through the five repair shapes without jumps using a bent x-scan. The dividing lines 2000, 2002, 2004, and 2006 drawn in the process each point to an inflection point of the outer loop line 2010 of the repair shape 108 (for example, one of the inflection points is denoted by reference numeral 2008).

[0128] In each case, the scan line method can be used to subdivide the repair shape 108 into repair sub-shapes as described in the above diagrams.

[0129] FIG. 21 shows the above aspect, where the scanning direction is selected based on the control bandwidth GF. Reference numeral 2100 denotes the longest edge of the repair shape 108. In the case of the repair shape 108 shown in FIG. 21, skipping occurs when scanning in the x direction. On the contrary, if the scanning is performed in the y direction (i.e., parallel to the longest edge 2100), as shown by the scanning line 406, each skipping can be avoided. However, such rotation is only possible, for example, after it has been confirmed that the unit 830 has been determined according to the control bandwidth GF. Therefore, if the skipping width in the scanning direction x is small, it can be managed without changing the scanning direction in the y direction (this also includes rotating the mask 100 by 90°).

[0130] FIG. 22 shows again the repair shape 108 known from FIG. 5. This repair shape 108 is subdivided into a rectangle 2200 and a rectangular ring 2202 (frame). All pixels corresponding to the defect D to be scanned are located therein.

[0131] Now, in order to implement step S2-3 (see FIG. 10), a repair shape 2300 is selected within the repair shape 2200 (see FIG. 23). It includes a contour 2300 that is recessed relative to the (right) edge 2204. The edge 2204 of the repair shape 2200 abuts a gap 2206 to be bridged within the range of the curved x scan. Therefore, the relative gap 2206 corresponds to the relative skipping of the electron beam 802, which allows the scanning line 406 to continue in the repair sub-region 2202.

[0132] FIG. 24 shows in an enlarged manner a part of FIG. 23 in the region of the edge 2204. The electron beam 802 continuously scans the pixels 2400, 2402, and 2404 in the scanning direction x. The electron beam skips at the pixel 2404 and continues its path on the scanning line 406 in the region 2202. This is acceptable for the repair process because the skipping is independent of the blurring or settling behavior. If the electron beam travels in the opposite direction, i.e., in the negative x direction, see the scanning line 406' in the region 2202, then the electron beam skips there and lands in the repair sub-region 2200. In principle, with the scanning mode unchanged, the electron beam will land on the pixel 2406. However, due to the settling behavior, this will result in an unexpected edge flatness. Therefore, the second repair shape 2300 is recessed relative to the first repair shape 2200 such that the electron beam does not reach the pixel 2406 but reaches the pixel 2408 after skipping the gap 2206; this is also referred to as "biasing" in this case.

[0133] Therefore, for repairing the repair sub-shape 2202, a repair shape 2500 having concave contours 2502 and 2504 as shown in FIG. 25 can also be confirmed. Therefore, in each case, the sedimentation behavior of the electron beam 802 considering the control bandwidth GF is taken into account.

[0134] Although the present invention has been described based on exemplary embodiments, the present invention can be modified in various ways.

[0135] 100: Reticle 100’: Reticle 102: Substrate 104: Coating; Absorbing layer; Pattern element; Coated area; Structured coating 108: Repair shape; Kidney shape; Annular segment 108’: Repair shape 200: Perfect image detail; “Perfect” area 200’: Defective image detail; Image 400: Curved x-scan; Curved scan 400’: Curved x-scan; Curved scan 402: Curved y-scan 404: Grating scan 406: Scan line 406’: Scan line 408: Skip 410: Pixel 410’: Pixel 410”: Pixel 410’’’: Pixel 500: Repair sub-shape; Repair shape; Rectangle 502: Repair sub-shape; Repair shape; Ring 504: Skip 600: Sedimentation curve 600’: Sedimentation curve 700: Skip 702: Edge 702’: Edge 800: Equipment 802: Electron beam 804: Vacuum housing 806: Vacuum pump 808: Sample platform 810: Electron column; Particle beam column 812: Electron source; Particle source 814: Electro-optical device 816: Deflection unit 818: Detector unit 820: Gas supply device 822: Valve 824: Gas pipeline 826: Computing device 828: Control unit 830: Confirmation unit 832: Memory unit; Data memory 1100: Notch 1102: Repair sub-shape 1104: Repair sub-shape 1200: Notch 1202: Skip 1300: Repair sub-shape 1302: Repair sub-shape 1304: Repair sub-shape 1306: Skip 1308: Portion 1310: Gap 1400: Repair sub-shape 1402: Repair sub-shape 1404: Repair sub-shape 1406: Repair sub-shape 1408: Repair sub-shape 1410: Repair sub-shape 1412: Skip 1413: Skip 1414: Skip 1416: Skip 1418: Skip 1420: Pixel 1422: Pixel 1424: Pixel 1500: Repair sub-shape 1502: Repair sub-shape 1504: Repair sub-shape 1506: Repair sub-shape 1508: Repair sub-shape 1510: Notch 1800: Edge area 1900: Quadrilateral 1902: Pentagon 2000: Separation line 2002: Separation line 2004: Separation line 2006: Separation line 2008: Inversion point 2010: Outline 2100: Longest edge 2200: Repair sub - shape; Rectangle; Repair shape; First repair shape 2202: Repair sub - region; Rectangle ring; First repair shape 2204: Edge 2206: Spacing 2300: Repair sub - shape 2302: Outline 2400: Pixel 2402: Pixel 2404: Pixel 2406: Virtual pixel 2408: Pixel 2410: Pixel 2500: Repair sub - shape 2502: Outline 2504: Outline A: Spacing AP: Amplitude A XS: Amplitude B: Structure width d: Width d1: Diameter d2: Diameter D: Defect f: Frequency GF: Control bandwidth O: Origin P: Position P0: Position; Point P1: Position; Point P2: Position; Point S1: Step S2: Step S2 - 1: Step; Variant S2 - 2: Step; Variant S2 - 3: Step; Variant S3: Step T: Time x: Scanning direction XS: Control signal y: Scanning direction

Claims

1. A method for processing defects (D) in a photomask (100), wherein a process gas is activated using a particle beam (802), wherein a control unit (828) is configured to control a deflection unit (816) having a control bandwidth (GF), wherein the deflection unit (816) for deflecting the particle beam (802) is configured to guide the particle beam (802) above the photomask (100), the method comprising the steps of: a) providing (S1) an image (200') of at least a portion of the photomask (100); b) Based on the control bandwidth (GF), the repair shapes (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) in the image (200') are confirmed, wherein the repair shapes (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) contain defects (D); and c) the deflection unit (816) is used to provide the particle beam (802) and activate the process gas at m pixels (410) of the repair shapes (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) to treat the defects (D).

2. The method as described in claim 1, wherein the control bandwidth (GF) is confirmed or provided before step a), and the confirmed or provided control bandwidth (GF) or its derived value is stored in data memory (832) and used in step b) before or during the operation of the particle beam column (810) for performing steps a) to c).

3. The method as described in claim 1, wherein step b) comprises: b1) Subdivide (S2-1) the repair shape (108) containing the defect (D) into k repair sub-shapes (1102, 1104) based on the control bandwidth (GF), and select one of the k repair sub-shapes (1102, 1104); and / or b2) Subdivide (S2-2) the repair shape (108) containing the defect (D) into k repair sub-shapes (1300-1304, 1400-1410) and select one of the k repair sub-shapes (1300-1304, 1400-1410), wherein the selection is performed based on the control bandwidth (GF), wherein step c) includes: The deflection unit (816) provides the particle beam (802) at m pixels (410) of the selected k repair sub-shapes (1300-1304, 1400-1410) and activates the process gas to treat the defect (D).

4. The method as described in any one of claims 1 to 3, wherein the implementation of the confirmation according to step b) or the subdivision according to step b1) and / or the selection according to step b2) is based on the spacing or jump width (d1, d2, 1202, 1306, 1310, 1412-1418) between the two repair shapes (108, 2200, 2002, 2300, 2500) or between two of the k repair sub-shapes (1300-1304, 1400-1410).

5. The method as described in any one of claims 1 to 3, wherein step c) comprises: The deflection unit (816) provides the particle beam (802) at m pixels (410) of the first repair shape (2200, 2202) or at m pixels (410) of the first of the k repair sub-shapes (500), and activates the process gas to treat the defect (D); The deflection unit (816) provides the particle beam (802) at n pixels (410''') of the second repair shape (2300, 2500) or at n pixels (410''') of the second of the k repair sub-shapes (502), and activates the process gas to treat the defect.

6. The method as described in any one of claims 1 to 3, wherein one of the m or n pixels, a first pixel (1422) and / or a last pixel (1424), is selected in a random manner.

7. The method as described in claim 3, wherein each of the k repair sub-shapes (1102, 1104, 1300-1304, 1400-1410) is formed continuously in the scanning direction (x) of the particle beam (802).

8. The method as described in claim 3, wherein step b1) or b2) employs a scanline method.

9. The method as described in any one of claims 1 to 3, wherein the repair shape (108) includes all openings (506, 1100, 1200, 1510) with a maximum dimension (d, d1, d2) between at least 5 nm and less than 10 μm.

10. The method as described in any one of claims 1 to 3, wherein the spacing (A) between two pixels (410) of one of the repair shape (108) or one of the k repair sub-shapes (500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) is less than 40, 20 or 5 nm.

11. The method as described in any one of claims 1 to 3, wherein the deflection unit (816) comprises an octagon for beam deflection.

12. The method as described in any one of claims 1 to 3, wherein in step c), the particle beam (802) moves along a straight line (406, 406') and / or along a plurality of parallel lines and / or with a plurality of lines perpendicular thereto (406, 406').

13. The method as described in any one of claims 1 to 3, wherein in step c), the particle beam (802) moves parallel to the longest edge (2100) of the repair shape (108) and / or one of the k repair sub-shapes (500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508).

14. The method as described in any one of claims 1 to 3, wherein in step b), a first repair shape (2200, 2202) containing the defect (D) and a second repair shape (2300, 2500) are identified, wherein the second repair shape (2300, 2500) is at least partially located within the first repair shape (2200, 2202).

15. The method as described in claim 14, wherein the contour of the second repair shape (2300, 2500) is recessed relative to the contour of the first repair shape (2200, 2202).

16. The method as described in claim 14, wherein the second repair shape (2300, 2500) portion has the same profile as the first repair shape (2200, 2202).

17. The method as described in claim 14, wherein when the first and second repair shapes (2200, 2202; 2300, 2500) overlap between two adjacent contours of the first and second repair shapes (2200, 2202; 2300, 2500), one or more pixels (2404, 2406) are positioned along an intersection line (406, 406') with the two adjacent contours (2204, 2302, 2502, 2504).

18. A computer program product containing a plurality of instructions, which, when a device (800) executes the instructions to handle a defect (D) in a photomask (100), causes the device (800) to perform method steps (S1-S3) as described in any one of claims 1 to 17.

19. An apparatus (800) for processing defects (D) in a photomask (100), comprising: a process gas supply device (820) for supplying a process gas; a particle source (812) for supplying a particle beam (802); a deflection unit (816) for deflecting the particle beam (802) to provide the particle beam (802) at m pixels (410) of the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) and activate the process gas; a control unit (828) for controlling the deflection unit (816) with a control bandwidth (GF); and a detector unit (818) for providing an image (200') of at least a portion of the photomask (100). A confirmation unit (830) is used to confirm, based on the control bandwidth (GF), the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) in the image (200'), wherein the repair shape (108, 500, 502, 1102, 1104, 1300-1304, 1400-1410, 1500-1508) contains the defect (D).

Images