METHOD FOR PARTICLE BEAM-INDUCED PROCESSING OF A DEFECT OF A MICROLITHOGRAPHIC PHOTOMASK

Abstract

A method for particle beam-induced processing of a defect of a microlithographic photomask, including the steps of: a1) providing an image of at least a portion of the photomask, b1) determining a geometric shape of a defect in the image as a repair shape, c1) subdividing the repair shape into a number of n pixels in accordance with a first rasterization, d1) subdividing the repair shape into a number of m pixels in accordance with a second rasterization, the second rasterization emerging from a subpixel displacement of the first rasterization, e1) providing an activating particle beam and a process gas at each of the n pixels of the repair shape in accordance with the first rasterization, and f1) providing the activating particle beam and the process gas at each of the m pixels of the repair shape in accordance with the second rasterization.

Claims

1. A method for particle beam-induced processing of a defect of a microlithographic photomask, including the steps of: a1) providing an image of at least a portion of the photomask, b1) determining a geometric shape of a defect in the image as a repair shape, c1) subdividing the repair shape into a number of n pixels in accordance with a first rasterization, d1) subdividing the repair shape into a number of m pixels in accordance with a second rasterization, the second rasterization emerging from a subpixel displacement of the first rasterization, e1) providing an activating particle beam and a process gas at each of the n pixels of the repair shape in accordance with the first rasterization, and f1) providing the activating particle beam and the process gas at each of the m pixels of the repair shape in accordance with the second rasterization.

2. The method of claim 1, wherein the subpixel displacement is a displacement, more particularly a lateral displacement, of the first rasterization by a subpixel dimension.

3. The method of claim 1, including the steps of: subdividing the repair shape into a number of 1.sub.i pixels in accordance with at least one further rasterization, with an i-th further rasterization being subdivided into l.sub.i pixels and the at least one further rasterization emerging from a subpixel displacement of the first, the second or any other one of the at least one further rasterizations, and providing the activating particle beam and the process gas at each of the l.sub.i pixels of the repair shape in accordance with the at least one further rasterization.

4. The method of claim 1, wherein step e1) is repeated before step f1) with a number g of repetition cycles and/or step f1) is repeated with a number h of repetition cycles.

5. The method of claim 1, wherein steps e1) and f1) are repeated with a number j of repetition cycles.

6. The method of claim 1, wherein the activating particle beam is in each case provided successively in a sequence at the n pixels, the m pixels and/or the 1.sub.i pixels of the repair shape, in which sequence a depletion of the process gas is implemented uniformly over the repair shape by a chemical reaction activated by the activating particle beam.

7. A method for particle beam-induced processing of a defect of a microlithographic photomask, including the steps of: a2) providing an image of at least a portion of the photomask, b2) determining a geometric shape of a defect in the image as a repair shape, and c2) providing a process gas at least along a stretch of the repair shape and guiding an activating particle beam along the stretch while simultaneously activating a chemical reaction between the process gas and a material of the photomask on the stretch.

8. The method of claim 7, wherein the activating particle beam is guided with a speed greater than zero along the entire stretch and/or wherein the activating particle beam is guided along the entire stretch without stopping.

9. The method of claim 7, wherein a length of the stretch is greater than or equal to 5 nm, greater than or equal to 10 nm, greater than or equal to 20 nm, greater than or equal to 50 nm, greater than or equal to 100 nm, greater than or equal to 200 nm and/or greater than or equal to 500 nm.

10. The method of claim 7, wherein the stretch extends linearly from one edge of the repair shape to an opposite edge of the repair shape.

11. The method of claim 7, wherein the stretch extends along an outer edge of the repair shape and/or along a parallel curve parallel to the outer edge of the repair shape.

12. The method of claim 7, wherein the repair shape is subdivided into at least a first and a second sub-repair shape, the stretch extends linearly from one edge of the first sub-repair shape to an opposite edge of the first sub-repair shape, and/or the stretch extends along an outer edge of the second sub-repair shape and/or along a parallel curve parallel to the outer edge of the second sub-repair shape.

13. The method of claim 7, wherein the activating particle beam is guided along the stretch with a speed greater than or equal to 0.01 m/s, greater than or equal to 0.02 m/s, greater than or equal to 0.03 m/s, greater than or equal to 0.05 m/s, greater than or equal to 0.1 m/s, greater than or equal to 1 m/s, greater than or equal to 5 m/s, greater than or equal to 10 m/s, greater than or equal to 50 m/s and/or greater than or equal to 100 m/s.

14. The method of claim 7, wherein the activating particle beam is guided over the entire repair shape in less than or equal to 500 ns, less than or equal to 400 ns, less than or equal to 300 ns, less than or equal to 200 ns, less than or equal to 100 ns and/or less than or equal to 50 ns.

15. The method of claim 7, wherein a beam current of the activating particle beam is greater than or equal to 0.0001 μA, greater than or equal to 0.001 μA, greater than or equal to 0.01 μA, greater than or equal to 0.1 μA and/or greater than or equal to 1 μA.

16. An apparatus comprising: a particle beam source configured to produce a particle beam; a particle beam guiding device configured to direct the particle beam; a computing device configured to: determine a repair shape for a defect of a microlithographic photomask, divide the repair shape into a number of n pixels in accordance with a first rasterization, divide the repair shape into a number of m pixels in accordance with a second rasterization, in which the second rasterization is based on a subpixel displacement of the first rasterization, control the particle beam guiding device to cause the particle beam to be directed at each of the number of n pixels, and control the particle beam guiding device to cause the particle beam to be directed at each of the number of m pixels; at least one storage container configured to store a process gas or at least one gaseous component of the process gas; and at least one gas provision device configured to provide the process gas or the at least one gaseous component of the process gas to the respective pixel of the repair shape.

17. The apparatus of claim 16, comprising a storage device storing instructions that when executed by the computing device causes the computing device to: determine the repair shape for the defect of the microlithographic photomask, divide the repair shape into the number of n pixels in accordance with the first rasterization, divide the repair shape into the number of m pixels in accordance with the second rasterization, in which the second rasterization is based on the subpixel displacement of the first rasterization, control the particle beam guiding device to cause the particle beam to be directed at each of the number of n pixels, and control the particle beam guiding device to cause the particle beam to be directed at each of the number of m pixels.

18. The apparatus of claim 16 in which the particle beam source comprises a scanning electron microscope, and the particle beam comprises an electron beam.

19. The apparatus of claim 18 in which the scanning electron microscope is configured to generate an image of at least a portion of the photomask including the defect, and wherein the computing device is configured to determine the repair shape for the defect based on the image of the at least a portion of the photomask including the defect.

20. The apparatus of claim 16 in which the computing device comprises a controller configured to: control the particle beam guiding device to cause the particle beam to be successively provided at each of the n pixels of the repair shape according to the first rasterization, and cause the particle beam to remain at each of the n pixels for a predetermined dwell time, and control the particle beam guiding device to cause the particle beam to be successively provided at each of the m pixels of the repair shape according to the second rasterization, and cause the particle beam to remain on each of the m pixels for a predetermined dwell time.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0103] FIG. 1 schematically shows a detail of a microlithographic photomask having a defect in a structured coating according to one embodiment;

[0104] FIG. 2 shows an apparatus for particle beam-induced processing of the defect of the photomask from FIG. 1 according to one embodiment;

[0105] FIG. 3 shows a partial detail of a further example of a defect of the photomask from FIG. 1, with a geometric shape (repair shape) of the defect being subdivided into a plurality of pixels in accordance with a first rasterization;

[0106] FIG. 4 shows five pixels from FIG. 3 in a magnified view;

[0107] FIG. 5 shows a view similar to FIG. 3, with the geometric shape (repair shape) of the defect being subdivided into a plurality of pixels in accordance with a second rasterization;

[0108] FIG. 6 shows a view similar to FIG. 3, with the geometric shape (repair shape) of the defect being subdivided into a plurality of pixels in accordance with a third rasterization;

[0109] FIG. 7 shows a view similar to FIG. 3, with the centers of the pixels according to the first, second and third rasterization being depicted overlaid on one another;

[0110] FIG. 8 shows a flowchart of a method for particle beam-induced processing of a defect of the photomask from FIGS. 1 to 7 in accordance with a first aspect;

[0111] FIG. 9 shows a further example of a defect of the photomask from FIG. 1, with a geometric shape (repair shape) of the defect not being subdivided into pixels but with a particle beam travelling over the repair shape continuously and vectorially along a plurality of stretches from one edge to the other edge of the repair shape;

[0112] FIG. 10 shows a further example of a defect of the photomask from FIG. 1, with a geometric shape (repair shape) of the defect not being subdivided into pixels but with a particle beam travelling over the repair shape continuously and vectorially along a plurality of stretches extending parallel to an outer contour of the repair shape;

[0113] FIG. 11 shows the defect from FIG. 10, with the repair shape being subdivided into two sub-repair shapes, in which the method from FIG. 9 is applied to the inner of the two sub-repair shapes and the method from FIG. 10 is applied to an outer of the two sub-repair shapes; and

[0114] FIG. 12 shows a flowchart of a method for particle beam-induced processing of a defect of the photomask from FIGS. 1 and 9 to 11 in accordance with a second aspect.

DETAILED DESCRIPTION

[0115] Unless indicated otherwise, elements that are the same or functionally the same have been given the same reference signs in the figures. It should also be noted that the illustrations in the figures are not necessarily true to scale.

[0116] FIG. 1 schematically shows a detail of a microlithographic photomask 100. In the example shown, the photomask 100 is a transmissive photolithographic mask 100. The photomask 100 comprises a substrate 102. The substrate 102 is optically transparent, especially at the wavelength with which the photomask 100 is exposed. By way of example, a material of the substrate 100 comprises fused quartz.

[0117] A structured coating 104 (pattern elements 104) has been applied to the substrate 102. In particular, the coating 104 is a coating made of an absorbing material. By way of example, a material of the coating 104 comprises a chromium layer. By way of example, a thickness of the coating 104 ranges from 50 nm to 100 nm. A structure dimension B of the structure formed by the coating 104 on the substrate 102 of the photomask 100 may differ at various positions of the photomask 100. By way of example, the width B of a region is plotted as structure dimension in FIG. 1. By way of example, the structure dimension B lies in a region of 20 to 200 nm. The structure dimension B may also be greater than 200 nm, for example be of the order of micrometers.

[0118] In other examples, other materials and other layer thicknesses (for example thinner layer thicknesses, e.g., “thin EUV mask absorber”) to the ones mentioned can also be used for the substrate and the coating. Furthermore, the photomask 100 can also be a reflective photomask rather than a transmissive photomask.

[0119] Occasionally, defects D can arise during the production of photomasks, for example because etching processes do not run exactly as intended. In FIG. 1, such a defect D is represented by hatching. This is excess material since the coating 104 was not removed from this region even though the two coating regions 104 next to one another are envisaged as separate in the template for the photomask 100. One could also say that the defect D forms a web. In this case, a dimension of the defect D corresponds to the structure dimension B. Other defects which are smaller than the structure dimension B, for example of an order of 5 to 20 nm, are also known. To ensure that a structure produced in a lithography apparatus using the photomask has the desired shape on a wafer and hence the semiconductor component produced in this way fulfils the desired function, it is necessary to repair defects, such as the defect D shown in FIG. 1 or else other defects. In this example, it is necessary to remove the web in a targeted manner, for example by particle beam-induced etching.

[0120] FIG. 2 shows an apparatus 200 for particle beam-induced processing of a defect of a microlithographic photomask, for example the defect D of the photomask 100 from FIG. 1. FIG. 2 shows schematically the section through a few components of the apparatus 200 which can be used for particle beam-induced repairing, in this case etching, of the defect D of the photomask 100. Moreover, the apparatus 200 can also be used for imaging the photomask, in particular the structured coating 104 of the mask 100 and of the defect D before, during and after the implementation of a repair process.

[0121] The apparatus 200 shown in FIG. 2 represents a modified scanning electron microscope 200. In this case, a particle beam 202 in the form of an electron beam 202 is used to repair the defect D. The use of an electron beam 202 as activating particle beam has the advantage that the electron beam 202 substantially cannot damage, or can only slightly damage, the photomask 100, in particular the substrate 102 thereof.

[0122] A laser beam for activating a local particle beam-induced repair process for the photomask 100 can be used instead of the electron beam 202 or in addition to the electron beam 202 in embodiments (not shown in FIG. 2). Further, instead of an electron beam and/or a laser beam, it is possible to use an ion beam, an atom beam and/or a molecule beam for activating a local chemical reaction (not shown in FIG. 2).

[0123] The apparatus 200 is largely arranged in a vacuum housing 204, which is kept at a certain gas pressure by a vacuum pump 206.

[0124] By way of example, the apparatus 200 is a repair tool for microlithographic photomasks, for example for photomasks for a DUV or EUV lithography apparatus.

[0125] A photomask 100 to be processed is arranged on a sample stage 208. By way of example, the sample stage 208 is configured to set the position of the photomask 100 in three spatial directions and for example additionally in three axes of rotation with an accuracy of a few nanometers.

[0126] The apparatus 200 comprises an electron column 210. The electron column 210 comprises an electron source 212 for providing the activating electron beam 202. Furthermore, the electron column 210 comprises electron or beam optics 214. The electron source 212 produces the electron beam 202 and the electron or beam optics 214 focus the electron beam 202 and direct the latter to the photomask 100 at the output of the column 210. The electron column 210 moreover comprises a deflection unit 216 (scanning unit 216) which is configured to guide (scan) the electron beam 202 over the surface of the photomask 100. Instead of the deflection unit 216 (scanning unit 216) arranged within the column 210, use can also be made of a deflection unit (scanning unit) (not shown) arranged outside of the column 210.

[0127] The apparatus 200 furthermore comprises a detector 218 for detecting the secondary electrons and/or backscattered electrons produced at the photomask 200 by the incident electron beam 202. By way of example, as shown, the detector 218 is arranged around the electron beam 202 in ring-shaped fashion within the electron column 210. As an alternative and/or in addition to the detector 218, the apparatus 200 can also contain other/further detectors for detecting secondary electrons and/or backscattered electrons (not shown in FIG. 2).

[0128] Moreover, the apparatus 200 can comprise one or more scanning probe microscopes, for example atomic force microscopes, which can be used to analyze the defect D of the photomask 100 (not shown in FIG. 2).

[0129] The apparatus 200 furthermore comprises a gas provision unit 220 for supplying process gas to the surface of the photomask 100. By way of example, the gas provision unit 220 comprises a valve 222 and a gas line 224. The electron beam 202 directed at a location on the surface of the photomask 100 by the electron column 210 can carry out electron-beam induced processing (EBIP) in conjunction with the process gas supplied by the gas provision unit 220 from the outside via the valve 222 and the gas line 224. In particular, said process comprises a deposition and/or an etching of material.

[0130] The apparatus 200 moreover comprises a computing apparatus 226, for example a computer, having a control device 228 and a determination device 230. In the example of FIG. 2, the computing apparatus 226 is arranged outside of the vacuum housing 204.

[0131] The computing apparatus 226, in particular the control device 228, serves to control the apparatus 200. In particular, the computing apparatus 226, in particular the control device 228, controls the provision of the electron beam 202 by way of driving the electron column 210. In particular, the computing apparatus 226, in particular the control device 228, controls the guidance of the electron beam 202 over the surface of the photomask 100 by driving the scanning unit 216. Moreover, the computing apparatus 226 controls the provision of the process gas by driving the gas provision unit 220.

[0132] Moreover, the computing apparatus 226 receives measured data from the detector 218 and/or other detectors of the apparatus 200 and produces images from the measurement data, which images can be displayed on a monitor (not shown). Moreover, images produced from the measured data can be stored in a memory unit (not shown) of the computing apparatus 226.

[0133] To check the photomask 100 and, in particular, the structured coating 104 of the photomask 100, the apparatus 200 is configured, in particular, to capture an image 300 of the photomask 100 (FIG. 1) or an image 300 of a detail of the photomask 100 from measured data from the detector 218 and/or other detectors of the apparatus 200. By way of example, a spatial resolution of the image 300 is of the order of a few nanometers.

[0134] The computing apparatus 226, in particular the determination device 230, is configured to recognize a defect D (FIG. 1) in the recorded image 300, to locate said defect and to determine a geometric shape 302 (repair shape 302) of the defect D. The determined geometric shape 302 of the defect D, that is to say the repair shape 302, is a two-dimensional geometric shape for example.

[0135] FIGS. 3 to 7 elucidate a method according to a first aspect for the particle beam-induced processing of a further example of a defect D′ of a structured coating 104 of the photomask 100 from FIG. 1. By way of example, the method is carried out using the apparatus shown in FIG. 2.

[0136] As described above in conjunction with FIGS. 1 and 2, an image 300 of at least a portion of the photomask 100 (FIG. 1) is recorded in step S1 of the method according to the first aspect.

[0137] As described above in conjunction with FIGS. 1 and 2, a geometric shape of a defect D′ is determined in the image 300 as a repair shape 302′ in step S2 of the method according to the first aspect. FIG. 3 shows a partial detail of the defect D′.

[0138] The repair shape 302′ (FIG. 3) is subdivided into a number of n pixels 304 in accordance with a first rasterization 306 in step S3 of the method according to the first aspect. In particular, the computing apparatus 226 (FIG. 2), more particularly the determination device 230, is configured to divide the repair shape 302′ (FIG. 3) into the number of n pixels 304 in accordance with the first rasterization 306.

[0139] In FIG. 3, three pixels 304 of the repair shape 302′ have been provided with a reference sign in an exemplary manner. In particular, the pixels 304 are arranged in columns (X direction) and lines (Y-direction, perpendicular to the X-direction). Each pixel 304 has a center M, three of the pixels being provided in FIG. 3 with a reference sign in an exemplary manner. FIG. 3 shows only a very small detail of the repair shape 302′. By way of example, the entire repair shape 302′ comprises 1 million pixels 304 (n=1 000 000). By way of example, a side length a of the pixels 304 is a few nanometers, for example 1.5 nm. By way of example, the pixels 304 have an area of 1.5 nm×1.5 nm. During the course of a repair method, the electron beam 202 (FIG. 2) is directed at the center M of each pixel 304 multiple times by use of the scanning unit 216. In particular, an intensity maximum of the for example Gaussian intensity profile of the electron beam 202 is directed at each center M of each pixel 304 multiple times over the course of the method. The number of pixels that the repair shape has, and the side length of each pixel, can be different from the exemplary values provided above.

[0140] FIG. 4 shows a magnified view of five of the pixels 304 of the repair shape 302′ shown in FIG. 3. Each pixel 304 has a square shape with a side length a. Consequently, the distance between two adjacent pixel centers M also equals a. The circles with diameter c and denoted by reference sign 308 represent areas of incidence of the electron beam 202 (FIG. 2) on the surface of the photomask 100. In this case, the diameter c corresponds to the side length a. The electron beam 202 has a radially symmetric Gaussian intensity profile, for example. In particular, the electron beam 202 is directed at a center M of the area of incidence 308 or of the pixel 304 such that a maximum of the intensity distribution thereof is incident on the center M within the scope of what is technically possible. By way of example, the areas of incidence 308 may correspond to a full width at half maximum of the intensity profile of the electron beam 202. However, the areas of incidence 308 may also correspond to any other intensity dropped from the maximum of the intensity distribution of the electron beam 202.

[0141] In step S4 of the method according to the first aspect, the repair shape 302′ (FIG. 3) is scanned by use of the electron beam 202 and with provision of the process gas such that the defect D′, the geometric shape of which is the repair shape 302′, is processed and rectified under the control of the computing apparatus 226 (FIG. 2), more particularly the control device 228. In this case, the activating electron beam 202 is successively directed at each of the n pixels 304 of the repair shape 302′. The electron beam 202 dwells at each of the n pixels 304 of the repair shape 302′ for a predetermined dwell time. In this case, a chemical reaction of the process gas is activated at each of the n pixels 304 of the repair shape 302′ by way of the electron beam 202. By way of example, the process gas comprises an etching gas. By way of example, the chemical reaction leads to volatile reaction products with the material of the defect D′ to be etched arising, which are at least partly gaseous at room temperature and which can be pumped away using a pump system (not shown).

[0142] After the electron beam 202 has been directed at each of the n pixels 304 of the repair shape 302 once (step e1)), this procedure is repeated over a number g of repetition cycles.

[0143] The repair shape 302′ is subdivided into a number of m pixels 304′ in accordance with a second rasterization 306′ (FIG. 5) in step S5 of the method according to the first aspect. In particular, the computing apparatus 226, more particularly the determination device 230, is configured to calculate the second rasterization from the first rasterization.

[0144] Step S5 can be performed before or after step S4.

[0145] FIG. 5 shows the same detail of the repair shape 302′ as FIG. 3. However, in contrast to FIG. 3, the repair shape 302′ is subdivided into m pixels 304′ in accordance with the second rasterization 306′ in FIG. 5. In particular, the second rasterization 306′ is calculated from the first rasterization 306 (FIG. 3) in accordance with a subpixel displacement. In particular, to form the second grid 306′ (FIG. 5), the first grid 306 (FIG. 3) was displaced to the right in FIGS. 3 and 4 by a length b, which corresponds to half a pixel length a in the example shown. In the example shown, the second rasterization 306′ has the same degree of fineness as the first rasterization 306. In particular, the pixels 304′ (FIG. 5) according to the second rasterization 306′ have the same dimension (pixel side length a) as the pixels 304 according to the first rasterization 306 (FIG. 3).

[0146] Then, the particle beam 202 is directed at each of the m pixels 304′ of the repair shape 302′ in accordance with the second rasterization 306′ in step S6 of the method according to the first aspect—in a manner analogous to what was the case for the n pixels 304 in accordance with the first rasterization 306.

[0147] In a step S7 of the method according to the first aspect, step S5 is carried out for one or more further rasterizations 306″ that differ from the first and the second rasterization 306, 306′. By way of example, FIG. 6 shows a third rasterization 306″, which emerges from the second rasterization 306′ by way of an upward displacement by half a pixel length a in FIGS. 5 and 6. That is to say the repair shape 302′ was subdivided into a number of 1 pixels 304″ in accordance with the third rasterization 306″. In the example shown, the pixels 304″ have the same dimension, that is to say side length a, as the pixels 304 (FIG. 3) and the pixels 304′ (FIG. 5). The second and/or the third rasterization 306′, 306″ may also be finer than the first rasterization 306 in other examples. In this case, the pixels 304′ and/or 304″ would have a smaller side length than the pixels 304.

[0148] In a step S8 of the method according to the first aspect, step S6 is carried out for the one or more further rasterizations 306″. By way of example, the activating particle beam 202 and the process gas are provided at each of the 1 pixels 304″ of the repair shape 302′ in accordance with the third rasterization 306″ (FIG. 6).

[0149] In FIG. 7, the centers M, M′ and M″ of the pixels 304, 304′ and 304″ are depicted in overlaid fashion. Over the course of steps S4, S6 and S8, the electron beam 202 is directed repeatedly at each center (point of incidence) M, M′, M″. As is evident in FIG. 7, an edge region 310 of the defect D′ can be scanned better by the second and third rasterization (centers M′ and M″) than is possible in the case where only the first rasterization (centers M) is applied.

[0150] In embodiments, steps S4, S6 and S8 are repeated over a number j of repetition cycles so that the overall number of repetition cycles for each of the n, m and 1 pixels 304, 304′, 304″ is e.g. (j×g) or (j×h).

[0151] To (completely) remove the coating 104 (FIG. 1) in the region of the defect D′, a total number j (or j×g or j×h) of repetition cycles of 100, 1000, 10 000, 100 000 or one million, for example, can be applied at each pixel 304, 304′, 304″.

[0152] FIGS. 9 to 12 elucidate a method according to a second aspect for the particle beam-induced processing of a further example of a defect D″ of a structured coating 104 of the photomask 100 from FIG. 1. By way of example, the method is carried out using the apparatus shown in FIG. 2. FIG. 9 shows a first embodiment of the method according to the second aspect.

[0153] As described above in conjunction with FIGS. 1 and 2, an image 300 of at least a portion of the photomask 100 (FIG. 1) is recorded in step S1′ of the method according to the second aspect.

[0154] As described above in conjunction with FIGS. 1 and 2, a geometric shape of a defect E is determined in the image 300 as a repair shape 402 in step S2′ of the method according to the second aspect. In step S2′ of the method according to the second aspect, the geometric shape is determined in particular as a vectorial form that is based on a vectorial representation. FIG. 9 shows a further example of a defect E′.

[0155] A process gas is provided at least along a stretch 404 (FIG. 9) of the repair shape 402 in step S3′ of the method according to the second aspect. Furthermore, an activating particle beam 202 (FIG. 2) is guided along the stretch 404 while simultaneously activating a chemical reaction between the process gas and a material of the photomask 100 (FIG. 1) on the stretch 404.

[0156] The stretch 404 according to the first embodiment (FIG. 9) of the method according to the second aspect extends linearly from an edge 406 of the repair shape 402 to an opposite edge 408 of the repair shape 402. In particular, the particle beam 202 is guided linearly along a first stretch 404 from a first starting point 410 at the first edge 406 to a first end point 412 at the second edge 408 without stopping. In particular, the first stretch 404 is the shortest path between the first starting point 410 and the first end point 412. A length of the first stretch 404 is provided with the reference sign l. The chemical reaction between the process gas and the mask material is initiated on the entire stretch 404 for the purposes of repairing the defect D′ during the continuous non-stop guidance of the particle beam 202 along the stretch 404.

[0157] Subsequently, the particle beam 202 at the second edge 408 is offset to a new second starting point 414 at the second edge 408 in a direction R perpendicular to the first stretch 404. Then, the particle beam 202 is guided along a second stretch 416 from the second starting point 414 to a second end point 418 at the first edge 406. By way of example, the second stretch 416 extends parallel to the first stretch 404.

[0158] In a corresponding manner, the entire repair shape can be swept by the particle beam 202 over a plurality of individual stretches 404, 416, 420, 422 (of which only four are shown and provided with a reference sign in FIG. 9). The activating particle beam 202 is guided with a speed greater than zero and without stopping (dwelling), in particular for each individual stretch 404, 416, 420, 422 along the entire individual stretch 404, 416, 420, 422.

[0159] FIG. 10 shows a second embodiment of the method according to the second aspect.

[0160] A first stretch 424 according to the second embodiment extends along an outer edge 426 and/or adjacent to the outer edge 426 of the repair shape 402′. In particular, the first stretch 424 extends from a first starting point 428 adjacent to the outer edge 426 along the entire outer edge 426 to a first end point 430 adjacent to the outer edge 426. In particular, the first end point 430 is arranged adjacent to the first starting point 428. Consequently, the particle beam 202 is guided along the first stretch 424 without stopping from the first starting point 428 to the first end point 430. The chemical reaction between the process gas and the mask material is initiated on the entire first stretch 424 during the guidance of the particle beam 202 along the first stretch 424.

[0161] Subsequently, the particle beam 202 is radially inwardly offset to a second starting point 432 from the outer edge 426 in the repair shape 402′. Then the particle beam 202 is guided from the second starting point 432 along a second stretch 434, which extends along a parallel curve parallel to the first stretch 424, to a second end point 436 on the parallel curve.

[0162] In a corresponding manner, the entire repair shape 402′ can be swept by the particle beam 202 over a plurality of individual stretches 424, 434, 438 (of which only three are provided with a reference sign in FIG. 10) that extend along parallel curves parallel to the outer edge 426. What applies to each of the individual stretches 424, 434, 438 in particular is that the activating particle beam 202 is guided along the entire individual stretch 424, 434, 438 at a speed greater than zero and without stopping (dwelling).

[0163] As a result of this beam guiding pattern, it is possible to obtain a suitable particle beam dose of the electron beam 202, in particular also in an edge region or at the outer edge 426 of the defect E″.

[0164] FIG. 11 shows a third embodiment of the method according to the second aspect.

[0165] According to the third embodiment, the repair shape 402′ is subdivided into at least a first and a second sub-repair shape 440, 442. In the example shown, the first sub-repair shape 440 is an inner region of the repair shape 402′. Moreover, the second sub-repair shape 442 completely surrounds the inner first sub-repair shape 440.

[0166] Within the first sub-repair shape 440, a respective individual stretch 444 extends linearly from an edge 446 to an opposite edge 448 of the first sub-repair shape 440 (analogously to the case shown in FIG. 9). Moreover, a first individual stretch 450 within the second sub-repair shape 442 extends adjacently to an outer edge 452 of the second sub-repair shape 442. Moreover, further individual stretches 454, 456 extend within the second sub-repair shape 442 along parallel curves parallel to the outer edge 452 of the second sub-repair shape 442.

[0167] In embodiments, a speed with which the electron beam 202 (FIG. 2) is guided along the corresponding stretch (404, 416, 420, 422 in FIG. 9; 424, 434, 438 in FIG. 10; 444, 450, 454, 456 in FIG. 11) in the method according to the second aspect can be so high that the exposure time for an entire repair shape 402, 402′ is of the order of the dwell time on a single pixel 304 (FIG. 3) in the method according to the first aspect. By way of example, a speed at which the electron beam 202 (FIG. 2) is guided along the corresponding stretch (FIGS. 9-11) is greater than or equal to 1 to 100 m/s. By way of example, the entire repair shape 402, 402′ is completely swept over once in less than or equal to 50 to 200 ns. By way of example, a particle beam 202 used to this end is provided with a beam current of greater than or equal to 0.0001 to 0.01 μA. However, a beam current of the particle beam 202 may also adopt other values (e.g., smaller values of a few pA) in other examples. As a result of this quasi simultaneous exposure of the entire repair shape 402, 402′, it is possible to obtain a particularly homogeneous particle beam dose over the entire repair shape 402, 402′ and hence possible to obtain an even better and more accurate repair of the defect E′, E″ (FIGS. 9-11) of the photomask 100 (FIG. 1).

[0168] In some implementations, the computing apparatus 226 (and/or the control device 228, the determination device 230) can include one or more data processors for processing data, one or more storage devices for storing data, such as one or more databases, and/or one or more computer programs including instructions that when executed by the computing apparatus 226 cause the computing apparatus 226 to carry out the processes. The computing apparatus 226 can include one or more input devices, such as a keyboard, a mouse, a touchpad, and/or a voice command input module, and one or more output devices, such as a display, and/or an audio speaker.

[0169] In some implementations, the computing apparatus 226 can include digital electronic circuitry, computer hardware, firmware, software, or any combination of the above. The features related to processing of data (e.g., one or more of the following:

[0170] determining (S2) a geometric shape of a defect (D, D′) in the image (300) as a repair shape (302, 302′), subdividing (S3) the repair shape (302, 302′) into a number of n pixels (304) in accordance with a first rasterization (306), subdividing (S5) the repair shape into a number of m pixels (304′) in accordance with a second rasterization (306′), the second rasterization (306′) emerging from a subpixel displacement of the first rasterization (306)) (e.g., one or more of the following: subdividing (S7) the repair shape (302′) into a number of l.sub.i pixels (304″) in accordance with at least one further rasterization (306″), with an i-th further rasterization (306″) being subdivided into 1, pixels (304″) and the at least one further rasterization (306″) emerging from a subpixel displacement of the first (306), the second (306′) or any other one of the at least one further rasterizations (306″)) (e.g., one or more of the following: subdividing the repair shape (402′) into at least a first and a second sub-repair shape (440, 442), determining stretches (444) that extend linearly from one edge (446) of the first sub-repair shape (440) to an opposite edge (448) of the first sub-repair shape (440), and determining stretches (450, 454, 456) that extend along an outer edge (452) of the second sub-repair shape (442) and/or along a parallel curve (454, 456) parallel to the outer edge (452) of the second sub-repair shape (442)) can be implemented in a computer program product tangibly embodied in an information carrier, e.g., in a machine-readable storage device, for execution by a programmable processor; and the method steps related to processing of data can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. Alternatively or addition, the program instructions can be encoded on a propagated signal that is an artificially generated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal, that is generated to encode information for transmission to suitable receiver apparatus for execution by a programmable processor.

[0171] In some implementations, the operations associated with processing of data described in this document can be performed by one or more programmable processors executing one or more computer programs to perform the functions described in this document. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0172] For example, the computing apparatus 226 can be configured to be suitable for the execution of a computer program and can include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only storage area or a random access storage area or both. Elements of the computing apparatus 226 can include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Generally, the computing apparatus 226 will also include, or be operatively coupled to receive data from, or transfer data to, or both, one or more machine-readable storage media, such as hard drives, magnetic disks, solid state drives, magneto-optical disks, or optical disks. Machine-readable storage media suitable for embodying computer program instructions and data include various forms of non-volatile storage area, including by way of example, semiconductor storage devices, e.g., EPROM, EEPROM, and flash storage devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM, DVD-ROM, and/or Blu-ray discs.

[0173] In some implementations, the processes that involve processing of data can be implemented using software for execution on one or more mobile computing devices, one or more local computing devices, and/or one or more remote computing devices. For instance, the software forms procedures in one or more computer programs that execute on one or more programmed or programmable computer systems, either in the mobile computing devices, local computing devices, or remote computing systems (which may be of various architectures such as distributed, client/server, or grid), each including at least one processor, at least one data storage system (including volatile and non-volatile memory and/or storage elements), at least one wired or wireless input device or port, and at least one wired or wireless output device or port.

[0174] In some implementations, the software may be provided on a medium, such as a CD-ROM, DVD-ROM, Blu-ray disc, solid state drive, or hard disk drive, readable by a general or special purpose programmable computer or delivered (encoded in a propagated signal) over a network to the computer where it is executed. The functions can be performed on a special purpose computer, or using special-purpose hardware, such as coprocessors. The software can be implemented in a distributed manner in which different parts of the computation specified by the software are performed by different computers. Each such computer program is preferably stored on or downloaded to a storage media or device (e.g., solid state memory or media, or magnetic or optical media) readable by a general or special purpose programmable computer, for configuring and operating the computer when the storage media or device is read by the computer system to perform the procedures described herein. The inventive system can also be considered to be implemented as a computer-readable storage medium, configured with a computer program, where the storage medium so configured causes a computer system to operate in a specific and predefined manner to perform the functions described herein.

[0175] Although the present invention has been described with reference to exemplary embodiments, it is modifiable in various ways.

LIST OF REFERENCE SIGNS

[0176] 100 Photomask [0177] 102 Substrate [0178] 104 Coating [0179] 200 Apparatus [0180] 202 Particle beam [0181] 204 Vacuum housing [0182] 206 Vacuum pump [0183] 208 Sample stage [0184] 210 Electron column [0185] 212 Electron source [0186] 214 Electron or beam optics [0187] 216 Scanning unit [0188] 218 Detector [0189] 220 Gas provision unit [0190] 222 Valve [0191] 224 Gas line [0192] 226 Computing apparatus [0193] 228 Control device [0194] 230 Determination device [0195] 300 Image [0196] 302, 302′ Repair shape [0197] 304, 304′, 304″ Pixel [0198] 306, 306′, 306″ Rasterization [0199] 308 Area of incidence [0200] 310 Edge region [0201] 402 Repair shape [0202] 404 Stretch [0203] 406 Edge [0204] 408 Edge [0205] 410 Starting point [0206] 412 End point [0207] 414 Starting point [0208] 416 Stretch [0209] 418 End point [0210] 420 Stretch [0211] 422 Stretch [0212] 424 Stretch [0213] 426 Edge [0214] 428 Starting point [0215] 430 End point [0216] 432 Starting point [0217] 434 Stretch [0218] 436 End point [0219] 438 Stretch [0220] 440 Sub-repair shape [0221] 442 Sub-repair shape [0222] 444 Stretch [0223] 446 Edge [0224] 448 Edge [0225] 450 Stretch [0226] 452 Edge [0227] 454 Stretch [0228] 456 Stretch [0229] a Length [0230] b Length [0231] B Structure dimension [0232] c Diameter [0233] D, D′ Defect [0234] E, E′, E″ Defect [0235] l Length [0236] M, M′, M″ Center [0237] R Direction [0238] S1-S8 Method steps [0239] S1′-S8′ Method steps [0240] X Direction [0241] Y Direction