METHOD AND APPARATUS FOR MASK REPAIR

Abstract

The present disclosure relates to methods, to an apparatus and to a computer program for processing of a lithography object. More particularly, the present invention relates to a method for removing a material, to a corresponding apparatus and to a method for lithographic processing of a wafer, and to a computer program for performing the methods. A method for processing a lithography object comprises, for example: providing a first gas comprising first molecules; providing a particle beam in a working region of the object for removal of a first material in the working region based at least partly on the first gas, wherein the first material comprises ruthenium.

Claims

1. A method for processing a lithography object, comprising: providing a first gas comprising first molecules; providing a particle beam in a working region of the object for removal of a first material in the working region based at least partly on the first gas, wherein the first material comprises ruthenium.

2. The method of claim 1, wherein the first material in the working region is fully removed.

3. The method of claim 1, wherein the first material is capable of absorbing radiation associated with the object.

4. The method of claim 1, wherein the first material corresponds to a layer material of a pattern element of the object.

5. The method of claim 1, wherein the first material further comprises at least a second element.

6. The method of claim 5, wherein the second element comprises at least one of the following: a metal, a semiconductor.

7. The method of claim 5, wherein the second element comprises at least one of the following: tantalum, chromium, nitrogen, oxygen.

8. The method of claim 5, wherein the ruthenium forms a chemical compound with the second element.

9. The method of claim 1, wherein the method is effected in such a way that a second material adjoining the first material is at least partly exposed in the working region by the removing.

10. The method of claim 9, wherein the first material and the second material differ in at least one element.

11. The method of claim 9, wherein the second material comprises tantalum and/or a tantalum compound.

12. The method of claim 9, wherein the method further comprises removing the second material in the working region.

13. The method of claim 12, wherein the method is effected in such a way that a third material adjoining the second material is at least partly exposed in the working region by the removing of the second material.

14. The method of claim 13, wherein the third material comprises ruthenium.

15. The method of claim 13, wherein the first material and the third material comprise the same elements.

16. The method of claim 13, wherein the second material and/or the third material corresponds to a layer material of a pattern element and/or to a material of a capping layer of a reflective layer stack of the object.

17. The method of claim 1, wherein the first molecules comprise a halogen atom.

18. The method of claim 1, wherein the first molecules comprise a noble gas halide.

19. The method of claim 18, wherein the noble gas halide comprises at least one of the following: xenon difluoride, XeF.sub.2, xenon dichloride, XeCl.sub.2, xenon tetrafluoride, XeF.sub.4, xenon hexafluoride, XeF.sub.6.

20. The method of claim 1, wherein the method further comprises: providing a second gas comprising second molecules, wherein the removing of the first material is also based at least partly on the second gas.

21. The method of claim 20, wherein a dipole moment associated with the second molecules comprises at least 1.6 D, preferably at least 1.7 D, more preferably at least 1.8 D, most preferably at least 1.82 D.

22. The method of claim 19, wherein the second molecules comprise water, H.sub.2O, and/or heavy water, D.sub.2O.

23. The method of claim 1, wherein the particle beam is based at least partly on an acceleration voltage of less than 3 kV, preferably less than 1 kV, more preferably less than 0.6 kV.

24. The method of claim 20, wherein the method is at least partly based on a temperature associated with the first gas and/or second gas, where the temperature is below 0° C. (273.15 K), preferably below −5° C. (268.15 K), more preferably below −10° C. (263.15 K), most preferably below −15° C. (258.15 K).

25. The method of claim 1, wherein the particle beam comprises an electron beam.

26. The method of claim 1, wherein the method is effected in such a way that a defect of the object is repaired.

27. The method of claim 1, wherein the object comprises an EUV mask and/or a DUV mask.

28. An apparatus for processing a lithography object, comprising: means of providing a first gas; means of providing a particle beam in a working region of the object, wherein the apparatus is configured to perform a method of claim 1.

29. A lithography object, wherein the object has been processed by a method of claim 1.

30. A method for processing of a semiconductor-based wafer, comprising: lithographic transferring of a pattern associated with a lithography object to the wafer, wherein the object has been processed by a method of claim 1.

31. A computer program comprising instructions which, when they are executed by a computer system, cause the computer system to perform a method of claim 1.

Description

DESCRIPTION OF DRAWINGS

[0126] The following detailed description describes technical background information and working examples of the invention with reference to the figures, which show the following:

[0127] FIG. 1 gives a schematic illustration in a top view of an illustrative repair situation for a lithography object.

[0128] FIG. 2 shows a schematic diagram of an illustrative method of the invention.

[0129] FIGS. 3A-3C give in a schematic illustration, in a cross section, by way of example, operations in a method of the invention.

[0130] FIG. 4 shows a schematic view of an illustrative apparatus of the invention.

[0131] FIG. 5 shows a schematic of a cross section through a pattern element of a lithography object, wherein the pattern element can be processed by an illustrative method of the invention.

DETAILED DESCRIPTION

[0132] FIG. 1 gives a schematic illustration in a top view of an illustrative repair situation for a lithography object. The lithography object may comprise here a lithographic mask suitable for any lithography method (e.g. EUV lithography, DUV lithography, i-line lithography, nanoimprint lithography etc.). In one example, the lithography mask may comprise an EUV mask, a DUV mask, an i-line lithography mask and/or a nanoimprinting stamp. In addition, the lithography object may comprise a binary mask (e.g. a chromium mask, an opaque MoSi on glass (OMOG) mask), a phase mask (e.g. a chromium-free phase mask), an alternating phase mask (e.g. a rim phase mask), a half-tone phase mask, a tritone phase mask and/or a reticle (for example with pellicle). The lithography mask may be used, for example, in a lithography method for the production of semiconductor chips.

[0133] The lithography object may comprise here (unwanted) defects. For example, a defect may be caused in the production of the object. In addition, a defect may also be caused by (lithography) processing of the object, a process deviance in the (lithography) processing, transport of the object, etc. On account of the usually costly and complex production of a lithography object, the defects are therefore usually repaired.

[0134] In the working examples described herein, for illustrative purposes, an EUV mask is frequently employed here as an example of a lithography object. However, rather than the EUV mask, any lithography object is conceivable (for example as described herein).

[0135] FIG. 1 can show, in schematic form, in a top view, two local states D, R of a detail 1000 of an EUV mask in the course of a repair of a defect in the mask. The detail 1000 shows part of a pattern element PE of the EUV mask. The pattern element PE may also be regarded as a pattern element (or else as a pattern structure) of the EUV mask. The pattern element PE may be part of a designed pattern which can be transferred to a wafer, for example, via a lithography method. The local state D shows an opaque defect 1010 adjoining the pattern element PE. The opaque defect 1010 may feature, for example, excess (opaque) material that should not be present at the defect side after mask development. The excess (opaque) material may correspond, for example, to an opaque material of the pattern element PE, or else to any other material of a layer of the pattern element PE (as described herein). In relation to FIG. 1 (state D), a defect-free pattern element PE in the detail 1000 would have to have a square shape, but it is clear that this target state does not exist as a result of the opaque defect 1010. A repair procedure RV therefore removes the excess (opaque) material in the region of the opaque defect 1010, such that a repaired state R of the pattern element PE can be created. Thus, it is shown in state R that no opaque effect occurs any longer in the original defect region 1020 (i.e. at the original site in the opaque defect) and there is no longer any excess (opaque) material. The removal of the defect 1010 accordingly re-establishes the target state of the rectangular shape of the pattern element PE after a repair operation.

[0136] During use in lithography apparatuses or lithography methods, a lithography mask may be subject to extreme physical and chemical environmental conditions. This is especially true of the exposure of EUV masks (and also DUV masks, or other masks as described herein) during a corresponding lithography method, in which the opaque material in particular of a pattern element PE may be subjected to these influences to a significant degree. For example, in the case of EUV exposure, a hydrogen plasma comprising free hydrogen radicals may be released, which can attack the opaque material of the pattern element PE among other materials and cause a material—altering and/or—removing effect. Further damage influences may occur in the EUV lithography process and mask cleaning processes. Damage to the mask material includes, for example, a chemical and physical alteration of the material by (EUV) radiation, temperature, and also a reaction with hydrogen or another reactive hydrogen species (e.g. free radicals, ions, plasma, etc.). The alteration of the material may also be caused by a reaction with purge gases (e.g. N2, extreme clean dry air—XCDA®, noble gases, etc.), in conjunction with the exposure radiation (e.g. EUV radiation, DUV radiation). The damage to the material may likewise arise or be enhanced by downstream processes (for example a mask cleaning operation). The downstream processes may, for example, additionally attack the opaque material of the pattern element PE that has previously been damaged by chemical/physical reactions during the exposure operation, and hence worsen the damage.

[0137] Therefore, the specific opaque material used in a pattern element PE may be a chemically resistant material. In particular, ruthenium-containing materials (as described herein) may be employed as resistant material for the pattern element PE in an EUV mask on account of their very high chemical stability. The ruthenium-containing materials may, for example, take the form of Ru.sub.aZ.sub.b (a, b≥0, Z: one or more further elements with the stoichiometric coefficient b applicable to the respective element). Z here may comprise a metal, nonmetal, semimetal, alkali metal (e.g., Li, Na, K, Rb, Cs). In addition, Z may comprise an alkaline earth metal (e.g. Be, Mg, Ca, Sr, Ba), a 3rd main group element (e.g. B, Al, Ga, In, Ti), a 4th main group element (e.g. C, Si, Ge, Sn, Pb), a 5th main group element (e.g. N, P, As, Sb, Bi). In addition, Z may comprise a chalcogenide (e.g. O, S, Se, Te), a halogen (e.g. F, Cl, Br, I) a noble gas (atom) (e.g. He, Ne, Ar, Kr, Xe), a transition group element (e.g. Ti, Hr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg).

[0138] However, this type of resistance (opaque) material of a pattern element PE or of an EUV mask can make the repair operation RV of an opaque defect 1010 significantly more difficult since the repair operation is to specifically remove the resistant (opaque) material.

[0139] FIG. 2 shows a schematic diagram of an illustrative method 200 of the invention. The method 200 may be employed in order to remove material from an EUV mask. In particular, the method 200 may be employed in order to remove material from an opaque defect 1010 in the course of a repair operation.

[0140] The method 200 may comprise here providing 210 of a first gas including first molecules. The first gas here may comprise, for example, XeF.sub.2 as first molecules. In addition, other gases are also conceivable as first gas, as described herein.

[0141] Other molecules are also suitable as first molecules of the first gas for the method 200. For example, polar and nonpolar triatomic molecules are conceivable. The first molecules may also comprise molecules that can be split into chlorine or fluorine radicals under suitable reaction conditions and/or additionally, for example, can be split into a further nonpolar species.

[0142] In addition, the method 200 may comprise providing 220 of a particle beam in a working region of the object for removal of a first material in the working region based at least partly on the first gas. The first material here may comprise ruthenium. It may also be a characteristic 230 of the method 200 that the first material comprises at least 50 atom percent of ruthenium, preferably at least 70 atom percent of ruthenium, especially preferably at least 90 atom percent of ruthenium. The method 200 may also comprise an electron beam as particle beam, such that electron beam-induced etching of the material by the method 200 may be enabled.

[0143] The first material here may especially correspond to the resistant (opaque) material of the EUV mask (as described herein), which is to be removed in the course of the repair of an opaque defect.

[0144] The method 200 may also comprise providing a second gas as additive gas that assists the etching process (for example with regard to etch selectivity, etch rate, anisotropy factor, etc.). In particular, in the case of electron beam-induced etching, the first gas used in the method 200 may be XeF.sub.2 and the additive gas H.sub.2O (i.e. water (vapor)). In addition, the second molecules may comprise a dipole moment between 1.6 D and 2.1 D, preferably between 1.7 D and 2 D, more preferably between 1.8 D and 1.95 D, most preferably between 1.82 D and 1.9 D. It is also conceivable that H.sub.2O is combined with nitrogen dioxide (or another oxidative gas) as additive gas.

[0145] FIGS. 3A-3C give a schematic illustration, in a cross section, by way of example, of procedures in the method 200 that can take place in the course of repair of a defect in a lithography object.

[0146] FIG. 3A presents, in schematic form, an illustrative characteristic layer structure of a reflective lithography mask for the UV wavelength region (i.e. an UV mask). The illustrative EUV mask 200 may be designed, for example, for an exposure wavelength in the region of 13.5 nm. For example, the EUV mask may comprise a phase-shifting EUV mask and/or a radiation-absorbing EUV mask. For example, the illustrative characteristic layer structure may be designed to be essentially radiation-absorbing for EUV lithography with a radiation-absorbing EUV mask (as described herein). For example, the illustrative characteristic layer structure may also be designed to be (essentially) phase-shifting for EUV lithography with a phase-shifting EUV mask. The EUV mask may include a substrate S made of a material with a low coefficient of thermal expansion, for example quartz. Other dielectrics, glass materials or semiconducting materials likewise can be used as substrates for EUV masks.

[0147] The substrate S may be adjoined by a deposited multilayer film or a reflective layer stack ML including, for example, 20 to 80 pairs of alternating molybdenum (Mo) and silicon (Si) layers, which may also be referred to as MoSi layers. The individual layers of the multilayer film ML may differ in refractive index, giving rise to a Bragg mirror that can reflect incident radiation (e.g. EUV radiation).

[0148] In order to protect the reflective layer stack ML, a capping layer D may be applied, for example, atop the uppermost layer of the reflective layer stack ML. The capping layer D may protect the reflective layer stack ML from damage by chemical processes during the production and/or during the use of the EUV mask (for example during a lithography method). The capping layer D may comprise here (elemental) ruthenium, and also elements or compounds of elements that increase reflectivity at wavelength 13.5 nm by not more than 3%. In addition, the capping layer D may comprise Rh, Si, Mo, Ti, TiO, TiO.sub.2, ruthenium compounds, ruthenium alloys, ruthenium oxide, niobium oxide, RuW, RuMo, RuNb, Cr, Ta, nitrides, and also compounds and combinations of the aforementioned materials. The capping layer may further comprise one of the following materials: RuRh, RuZr, RuZrN, RuNbN, RuRhN, RuV, RuVN.

[0149] Atop the capping layer D there may be several layers that may include, for example, the layers of the pattern element (i.e. pattern element layers). The pattern element layers may comprise a buffer layer P, an absorption layer A and/or a surface layer O. The properties of the pattern element layers (for example an intrinsic material property of a pattern element layer, a layer thickness of a pattern element layer, etc.) and the geometry of the pattern element PE shaped therefrom may be designed to cause an opaque effect in relation to the exposure wavelength of the EUV mask. For example, the pattern element PE may be designed such that it is opaque (i.e. non-transparent to light or highly light-absorbing) with respect to light radiation having a wavelength of 13.5 nm. The pattern element layers may correspond to the layers of the opaque defect 1010, although the opaque defect 1010 need not necessarily have all the pattern element layers. For example, the opaque defect 1010 may have merely the buffer layer P and the absorption layer A.

[0150] The buffer layer P may be present atop the capping layer D. In addition, the absorption layer A may be present atop the buffer layer P. The absorption layer A may be designed to be effective in absorbing the radiation of lithography wavelengths (as described herein). Accordingly, the absorption layer A may make the main contribution to an opaque effect of the pattern element (or of the opaque defect 1010). The optical properties of the absorption layer A can be described, for example, by a complex refractive index that may include a phase shift contribution (i.e. n) and the adsorption contribution (i.e. k). For example, n and k may be regarded as intrinsic material properties of the absorption layer. Only particular chemical elements and/or compounds of chemical elements have advantageous phase-shifting and/or absorptive properties for the corresponding lithography method (e.g. an EUV lithography method). FIG. 3A indicates, by way of example, the layer thickness d of the absorption layer A. The layer thickness d of the absorption layer A (and also a layer thickness of another layer of the mask) is ascertained, for example, along a normal vector in relation to the plane of the mask. In principle, it is also conceivable that the absorption layer A comprises multiple absorption layers including different materials, for example. In addition, the surface layer O may be present atop the absorption layer A. The surface layer O may comprise an antireflection layer, oxidation layer and/or passivation layer. As well as the absorption layer A, it is also possible for the buffer layer P and/or the surface layer O to contribute to the absorption and to the opaque effect of the pattern element PE or of the opaque defect 1010.

[0151] In principle, any of the pattern element layers described herein may include the resistant first material mentioned (i.e. ruthenium-containing material). Typically, for example, the absorption layer A includes ruthenium. The first material in the method 200 may accordingly comprise a material of the absorption layer A. In addition, it is alternatively possible, for example, for the buffer layer P or the surface layer O to include ruthenium and hence to constitute the first material in the method 200.

[0152] FIG. 3B shows the result of an illustrative method 200 for removal of part of the absorption layer A. The absorption layer A is designed as the first material in the method 200. Initially, part of the surface layer O may first be removed. For example, this can be effected analogously to the method 200 via electron beam-induced etching in a separate step. The surface layer need not necessarily be removed with the first and/or second gas (as described herein). It is also conceivable that the electron beam-induced etching is designed exclusively for the removing of the surface layer (for example with an etching gas matched to the material of the surface layer). After the surface layer O has been removed, it is then possible to remove part of the absorption layer A as the first material in the method 200 (for example to repair an opaque defect). FIG. 3B illustrates selective electron beam-induced etching of the absorption layer A with respect to the buffer layer P. Accordingly, the method 200 may be adjusted such that the etch rate of the absorption layer A is elevated compared to the etch rate of the buffer layer P. For example, the etching selectivity can be adjusted via the properties of the second gas in the method 200 (for example via a suitable choice of the second gas (e.g. water), or the gas flow rate of the second gas). In addition, the etch selectivity can also be adjusted by the properties of the first gas (for example via the choice of first gas (e.g. XeF.sub.2), or via the gas volume flow rate of the first gas). In this example, the buffer layer P accordingly functions as etch stop via the etch selectivity chosen.

[0153] FIG. 3C shows a further result of an illustrative method 200 for removal of part of the absorption layer A. Initially, it is possible here (as described herein) to remove a portion of the buffer layer O. After the surface layer O has been removed, it is then possible to remove part of the absorption layer A as the first material in the method 200. It is also possible here to etch a portion of the buffer layer P as intermediate material. Accordingly, the method 200 may be adjusted such that the etch rate of the absorption layer A, and also the etch rate of the buffer layer P, are elevated compared to the etch rate of the capping layer D. The etch rate of the absorption layer A may be in the same order of magnitude as the etch rate of the buffer layer P. The etch selectivity may be adjusted as described herein. As shown in FIG. 3C, this can achieve selective electron beam-induced etching of the absorption layer A and of the buffer layer P with respect to the capping layer D. In this example, the capping layer D therefore functions as etch stop via the etch selectivity chosen.

[0154] In one example, the surface layer O is not removed separately, but via the same process which is employed for the local removing of the absorption layer A (or of the absorption layer A and the buffer layer P) in a method 200.

[0155] It should also be mentioned that the parameter space (e.g. gas parameters of the first/second gas, particle beam parameters) of the method 200 may depend firstly on the layer currently being processed (by the particle beam). This may correspond, for example, to stepwise removal of layers (or materials), with adjustment of the parameter space of the method 200 for each layer (or each of the materials). However, it is also possible that the parameter space of the method 200 does not depend on the layer currently being processed (with the particle beam). This approach too can, for example, remove multiple layers (or materials) successively.

[0156] The method 200 can additionally also be employed for a different specific layer structure of the lithography object from that shown in FIGS. 3A-3C. The specific layer structure of the object (for example the EUV mask) may, as before, include here a capping layer adjoining a reflective layer stack of the object. This capping layer may be adjoined by a first layer. This first layer may be adjoined by a second layer. Proceeding from the substrate, the specific layer structure may accordingly comprise the following layers in this sequence: substrate, reflective layer stack, capping layer, first layer, second layer. The first and second layers may account for one layer of a pattern element here. In one example, the first and second layers are specifically designed as absorption layers for a pattern element (for example in relation to the lithography method). The absorption of the lithography wavelength (as described herein) can be effectively defined here via the two layers (i.e. the first and second layers). For example, the first and second layers may have different thicknesses, in order to configure the optical properties of the lithography object. In a first example of the specific layer structure, the capping layer may include ruthenium and niobium. The first layer here may comprise tantalum, boron and oxygen. The second layer may comprise ruthenium, chromium and nitrogen. In a second example, the specific layer structure is defined in that the capping layer includes essentially ruthenium, while the first layer comprises tantalum, oxygen and nitrogen (e.g. tantalum oxynitride, TaON). In this second example, the second layer of the specific layer structure may comprise ruthenium and oxygen (this may, for example, be ruthenium oxide, which can be referred to, for example, as RuOx).

[0157] Based on the specific layer structure described herein, the first material (for the purposes of the method 200 or the method in the first aspect) may correspond to a material of the second layer. The second material (for the purposes of the method 200 or the method in the first aspect) may correspond to a material of the first layer. The third material (for the purposes of the method 200 or the method in the first aspect) may correspond to a material of the capping layer. In one example, the first layer of the specific layer structure too comprises ruthenium (for example as the absorption layer as well). In that case, the material of the first layer may comprise features/properties as described herein for the first material.

[0158] For the first example of the specific layer structure, the inventors have recognized here particularly advantageous parameter spaces for the controlled removing of the first material (Ru, Cr, N in this case) and of the second material (Ta, B, O in this case), with use of the third material (the capping layer of Ru, Nb in this case) for determination of the end point of the method. For advantageous results, the first gas used in the test series was XeF.sub.2, and the additive gas H.sub.2O. A first test series comprised the following process properties: a XeF.sub.2 precursor reservoir at a temperature of −15° C., which was used to form the XeF.sub.2 gas, an H.sub.2O precursor reservoir at a temperature of −36° C., which was used to form the H.sub.2O gas, a dwell time of the electron beam of 0.1 μs, a frame refresh rate of 1000 μs. In addition, gas chopping was used here in the providing of the second (additive) gas with a gas chopping ratio of 1:15. In other examples, the two precursor reservoirs may be at different temperatures, for example below 0° C.; for example, the XeF.sub.2 precursor reservoir at −30° C. to 0° C. or −25° C. to −5° C.; for example, the H.sub.2O precursor reservoir at −50° C. to −20° C. or −45° C. to −25° C. The frame refresh rate in these examples may vary from 0.1 to 10 ms, preferably 0.2 to 5 ms, more preferably 0.5 to 2 ms, where the gas chopping ratio may be chosen within the range from 1:5 to 1:25 or 1:10 to 1:20. Gas chopping comprises here the continuous providing of the additive gas over a particular period t.sub.X of a sequence: after the particular period of time t.sub.X has elapsed, the provision of the second gas is suspended for time t.sub.Y until the sequence has elapsed. The duration of a sequence (i.e. t.sub.S) can accordingly be described over the total duration t.sub.S=t.sub.X+t.sub.Y. After the sequence has elapsed, a new sequence is commenced with the described time lapses in the providing of the additive gas, with a repetition of the operation as often as desired (for example up to the end of the method). It is thus possible for the providing of the additive gas to take place in a “pulsed” form (rather than continuous provision). The gas chopping ratio (e.g. 1:15) indicates here the ratio of the provision time t.sub.X to the non-provision time t.sub.Y of the gas over a sequence. The gas chopping ratio may indicate here the provision time t.sub.X and the non-provision time t.sub.Y in seconds (for example, a gas chopping ratio of 1:15 may mean that t.sub.X is one second and t.sub.Y is 15 seconds, where the corresponding sequence t.sub.S is 16 seconds).

[0159] A second test series was executed with an XeF.sub.2 precursor reservoir at a temperature of −20° C. and an H.sub.2O precursor reservoir at a temperature of −34° C., a dwell time of the electron beam of 0.05 μs, a frame refresh rate of 1000 μs. A gas chopping ratio of 1:15 was used here. In other examples, the two precursor reservoirs may be at different temperatures, for example below 0° C.: for example, the XeF.sub.2 precursor reservoir at −40° C. to 0° C. or −30° C. to −15° C.; for example, the H.sub.2O precursor reservoir at −50° C. to −20° C. or −45° C. to −25° C. The frame refresh rate in these examples may vary from 0.1 to 10 ms, preferably 0.2 to 5 ms, more preferably 0.5 to 2 ms, where the gas chopping ratio may be chosen within the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20. A third test series was executed with an XeF.sub.2 precursor reservoir at a temperature of −10° C. and an H.sub.2O precursor reservoir at a temperature of −36° C., a dwell time of the electron beam of 0.1 μs, a frame refresh rate of 1000 μs. A gas chopping ratio of 1:1 was used here. In other examples, the two precursor reservoirs may be at different temperatures, for example below 0° C.: for example, the XeF.sub.2 precursor reservoir at −20° C. to 0° C. or −15° C. to −5° C.; for example, the H.sub.2O precursor reservoir at −50° C. to −20° C. or −40° C. to −30° C. The frame refresh rate in these examples may be from 0.1 to 10 ms, preferably 0.2 to 5 ms, more preferably 0.5 to 2 ms, where the gas chopping ratio may be chosen within the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20.

[0160] For the second example of the specific layer structure, the inventors have likewise recognized advantageous parameter spaces for the controlled removing of the first material (RuOx, i.e. ruthenium oxide, in this case) and of the second material (TaON in this case), with use of the third material (the capping layer of Ru in this case) for determination of the end point of the method. For advantageous results, the first gas used for each test series in the second example was XeF.sub.2, and the additive gas H.sub.2O. Also examined here, however, was what influence an additional oxidative gas (nitrogen dioxide in this case) in the additive gas has on the removing. The test series in the second example were numbered from test series four to test series seven, proceeding from the test series in the first example of the specific layer structure. Thus, a fourth test series was executed with an XeF.sub.2 precursor reservoir at a temperature of −15° C. and an H.sub.2O precursor reservoir at a temperature of −36° C., a dwell time of the electron beam of 0.1 μs, a frame refresh rate of 1000 μs. A gas chopping ratio of 1:30 was used here. In other examples, the two precursor reservoirs may be at different temperatures, for example below 0° C.: for example, the XeF.sub.2 precursor reservoir at −30° C. to 0° C. or −20° C. to −5° C.; for example, the H.sub.2O gas at −50° C. to −20° C. or −40° C. to −30° C. A fifth test series corresponded to the parameters specified herein for the fourth test series, with additional provision of nitrogen dioxide (with a gas volume flow rate of 1.2 sccm). A sixth test series was executed with an XeF.sub.2 precursor reservoir at a temperature of −20° C. and an H.sub.2O precursor reservoir at a temperature of −36° C., a dwell time of the electron beam of 0.1 μs, a frame refresh rate of 1000 μs. A gas chopping ratio of 1:30 was used here. In other examples, the two precursor reservoirs may be at different temperatures, for example below 0° C.: for example, the XeF.sub.2 precursor reservoir at −40° C. to 0° C. or −30° C. to −10° C.; for example, the H.sub.2O precursor reservoir at −50° C. to −20° C. or −40° C. to −30° C. A seventh test series corresponded to the parameters specified herein for the sixth test series, with additional provision of nitrogen dioxide (with a gas volume flow rate of 1.2 sccm). In a scanning electron micrograph, a sharper edge profile of the etched structures was attributable to the test series that had nitrogen dioxide and water as additive gas. It should also be mentioned that, for the method of processing in the second example of the specific layer structure, the frame refresh rate may also vary from 0.1 to 10 ms, preferably 0.2 to 5 ms, more preferably 0.5 to 2 ms, where the gas chopping ratio may also be chosen within the range from 1:1 to 1:10, 1:5 to 1:25 or 1:10 to 1:20.

[0161] In the test series described herein, during the method (i.e. in the removing of the first and second material, and also in processing of the third material with the particle beam), the intensity of the signal of the electrons that were released from the working region was determined. The intensity was determined here depending on the dose of the particle beam (an electron beam in the examples). The dose corresponded here to the dose that was introduced over the course of the method via the region to be etched (the working region), with determination of the intensity via a backscattered electron detector. It was possible here to ascertain that the intensity depends on the material on which the particle beam is acting. It was possible here to assign a particular value (or range of values) of intensity to a particular material or to a layer of the specific layer structure. It was thus possible to monitor the removing of the various layers of the specific layer structure via the progression of intensity as a function of dose. For example, in the case of a (significant) change in intensity (for example a local positive and/or negative rise in the intensity progression), it was possible to conclude that the removing results in a change from a previously exposed layer to an (underlying) different layer which is now also being exposed, but causes a different intensity signal of the electrons. For example, it was possible to detect the material of the previously exposed layer with an intensity I.sub.X, and to detect the material of the other layer with an intensity I.sub.Y, with I.sub.Y<I.sub.X (or I.sub.Y>I.sub.X). In a transition phase, it was possible to detect a decreasing (increasing) intensity between I.sub.x and I.sub.y, which caused the drop (rise) in the intensity progression. In addition, in the case of a (predominantly) constant progression of intensity, it was possible to conclude, for example, that an exposed layer is being processed. This was attributable to the fact that no (significant) change in intensity was apparent, which could be explained by a change in the material exposed. These characteristic properties of the intensity progression that are associated, for example, with the change in the expose layer, and also with the processing of an exposed layer, can serve to determine an endpoint of the method.

[0162] In addition, for the test series described herein (i.e. test series one to seven), a corresponding etch depth was determined depending on selected (introduced) doses of the particle beam. For this purpose, for a test series, multiple geometrically identical test structures (or identical test areas/working regions to be etched) were subjected to the corresponding method, with the only difference in the dose (introduced) in the various test structures. It was thus possible to assess the influence of the dose (introduced) of the particle beam for the corresponding methods. The etch depths of the test structures were determined by atomic force microscopy here. These items of information were usable for a progression of etch depth as a function of the (introduced) dose for the corresponding methods, with a plot of etch depth on the ordinate and of the selected (introduced) dose on the abscissa. The progression of etch depth likewise enabled conclusions in order to decide the specific layer structure. The (local) rises in the progression of edge depth were determined here by means of linear regression, with the (local) rise corresponding to an etch rate. By virtue of the material-specific differences, the different materials of the specific layer structure also have different etch rates. These differences in etch rates were usable to deduce which characteristic section of the etch profile progression can be assigned to the first layer, to the second layer or to the capping layer.

[0163] The method 200 accordingly comprises, in one example, the determining of an endpoint of the method based on a particular etch rate (or a particular difference in etch rates) and/or a particular intensity progression in the signal of the electrons. The determining of the etch rate and/or the intensity progression (as described herein) may, for example, precede the actual removing of the first material (for example in a calibration experiment).

[0164] It is also conceivable that the specific layer structure is defined by further layers. For example, it is conceivable that there is at least one buffer layer between the capping layer and the first layer. In this case, the buffer layer may comprise the features of the buffer layer P of FIGS. 3A-3C described herein. In this connection, the buffer layer of the specific layer structure may correspond to the intermediate material (as described herein). The specific layer structure may also be designed such that, as well as the first and second layers, at least a third layer is present, where the third layer may constitute an absorption layer of the pattern element. It is thus possible, for example, for a pattern element to be configured with three or more absorptions layers on the lithography object. For example, the first and second layers may here be attached alternately atop the capping layer (for example, the layer sequence may comprise capping layer, first layer, second layer, first layer, second layer, etc.).

[0165] It should be mentioned that the ruthenium-containing absorption layers specified herein may include ruthenium and at least one of the following metals: Nb, Zr, Y, B, Ti, La, Mo, Co, Re. In addition, the ruthenium-containing material may comprise at least one of the following: N, O, H, C.

[0166] In addition, the ruthenium-containing material may comprise at least one of the following transition metals: Mo, Ta, W, Ti, Cr, Hf, Ni, V, Zr, Rh, Nb, Pd. In a further example, the ruthenium-containing material may also comprise the following: Cr, Ni, Co, V, Nb, Mo, W, Re, Ta.

[0167] In principle, it may also be necessary in a mask repair to produce or to deposit material (as repair material). In the case of mask repair by use of electron beam-induced deposition of ruthenium (for example in the form of Ru.sub.aZ.sub.b, as described herein), ruthenium oxides or other ruthenium-containing deposits may also result here in unwanted material deposition. Unwanted material deposition may be caused, for example, by off-target strands of the electron beam and secondary electrons generated thereby. In addition, unwanted deposition (of the repair material) may be caused by secondary electrons produced at sites adjacent to the repaired defect, and also by secondary electrons that escape at vertical edges of the process material and propagate to sites adjacent to the repaired defect. It is likewise possible for forwardscattered electrons (FSE) that escape from the flanks of existing material and backscattered electrons (BSE) that escape from the surface in the environment of the repaired site to contribute to unwanted material deposition.

[0168] A further application of the method 200 is therefore the removal of material that has been deposited by these mechanisms mentioned on areas adjacent to the repaired defect. In one example, the method 200 therefore also comprises the producing of a repair material.

[0169] In the course of production of the repair material, it is possible to use a deposition gas in the electron beam-induced deposition. It is possible here for at least one of the following to be included as deposition gas in the invention: (metal, transition element, main group) alkyls such as cyclopentadienyl (Cp) or methylcyclopentadienyl (MeCp) trimethylplatinum (CpPtMe.sub.3 or MeCpPtMe.sub.3), tetramethyltin SnMe.sub.4, trimethylgallium GaMe.sub.3, ferrocene Cp.sub.2Fe, bisarylchromium Ar.sub.2Cr, ruthenocene Cp.sub.2Ru and other compounds of this kind. In addition, at least one of the following may be included in the invention as first gas: (metal, transition element, main group) carbonyls such as chromium hexacarbonyl Cr(CO).sub.6, molybdenum hexacarbonyl Mo(CO).sub.6, tungsten hexacarbonyl W(CO).sub.6, dicobalt octacarbonyl Co.sub.2(CO).sub.8, triruthenium dodecacarbonyl Ru.sub.3(CO).sub.12, iron pentacarbonyl Fe(CO).sub.5 and other compounds of this kind. In addition, one of the following may be included in the invention as first gas: (metal, transition element, main group) alkoxides such as tetraethoxysilane Si(OC.sub.2H.sub.5).sub.4, tetraisopropoxytitanium Ti(OC.sub.3H.sub.7).sub.4 and other compounds of this kind.

[0170] It is also possible for at least one of the following to be included as deposition gas in the invention: (metal, transition element, main group) halides such as WF.sub.6, WCl.sub.6, TiCl.sub.6, BCl.sub.3, SiCl.sub.4 and other compounds of this kind. In addition, at least one of the following may be included in the invention as deposition gas: (metal, transition element, main group) complexes such as copper bis(hexafluoroacetylacetonate) Cu(C.sub.5F.sub.6HO.sub.2).sub.2, dimethylgold trifluoroacetylacetonate Me.sub.2Au(C.sub.5F.sub.3H.sub.4O.sub.2), dicarbonylbisdiketonateruthenium and other compounds of this kind. It is also possible for at least one of the following to be included as deposition gas in the invention: organic compounds such as CO, CO.sub.2, aliphatic or aromatic hydrocarbons, constituents of vacuum pump oils, volatile organic compounds and further such compounds.

[0171] The method 200 (or the method in the first aspect) may be executed via the apparatus of the invention described herein. In one example, the apparatus comprises a mask repair apparatus for repair or processing of lithography masks. The apparatus may be used to localize and to repair or remedy mask defects. The apparatus may comprise parts such as the apparatus described in US 2020/0103751 A1 (see the corresponding FIG. 3A therein). The apparatus may comprise, for example, a control unit which may, for example, be part of a computer system. The apparatus, in one example, may be configured such that the computer system and/or the control unit controls the process parameters of the method in the first aspect as disclosed herein. This configuration can enable controlled, and also automated, implementation of the method according to the invention as specified herein, for example without manual interventions. This configuration of the apparatus can be achieved or enabled, for example, via the computer program according to the invention as described herein.

[0172] FIG. 4 shows a schematic section of an illustrative apparatus 400 according to the invention. The apparatus 400 may be configured such that it can perform the method 200 or a method in the first and/or second aspect of the invention. In one example, the apparatus 400 of FIG. 4 comprises a mask repair apparatus for repair or processing of lithography masks. The apparatus 400 may be used to localize and to repair or remedy mask defects.

[0173] The illustrative apparatus 400 of FIG. 4 may comprise, for example, a scanning electron microscope (SEM) 101 for provision of a particle beam, which, in this example, is an electron beam 409. An electron gun 406 can generate the electron beam 409, which can be directed by one or more beam-forming elements 408 as a focused electron beam 110 onto a lithography mask 402, which is arranged on a sample stage 404 (or chuck). In addition, the scanning electron microscope can be used to control parameters/properties of the electron beam (e.g. acceleration voltage, dwell time, current, focusing, spot size, etc.) The parameters of the electron beam may be adjusted, for example, in relation to a parameter space of the methods described herein. The electron beam 409 may serve as an energy source for initiating a local chemical reaction in a working region of the lithography mask 402. This may be utilized, for example, for the methods described herein (for example for the implementation of the electron beam-induced etching in the first aspect). In addition, the electron beam 409 may be utilized for imaging of the lithography mask 102. The apparatus 400 may comprise here one or more detectors 414 for detecting electrons (for example secondary electrons, backscattered electrons).

[0174] In order to conduct the corresponding methods specified herein, the illustrative apparatus 400 of FIG. 4 may include at least two reservoir vessels for at least two different processing gases or precursor gases. The first reservoir vessel G1 can store the first gas. The second reservoir vessel G2 can store the second gas. In some examples, the temperatures of reservoir vessels G1 and G2 may be controlled independently of one another. The second gas may also be regarded as an additive gas. In addition, in the illustrative apparatus 400, each reservoir vessel G1, G2 has its own gas inlet system 432, 447, which can end with a nozzle close to the point of incidence of the electron beam 410 on the lithography mask 402. It is possible for each reservoir vessel G1 G2 to have its own control valve 446, 431 in order to control the amount of the corresponding gas provided per unit time, i.e. the gas flow rate of the corresponding gas. This can be effected in such a way that the gas volume flow rate is controlled at the point of incidence of the electron beam 410. In addition, the apparatus 400, in one example, may include further reservoir vessels for additional gases that can be added to the method in the first aspect as one or more (additive) gases (e.g. oxidizing agent, reducing agent, halides as described herein). The apparatus 400 in FIG. 4 may include a pump system for generating and maintaining a pressure required in the process chamber 485.

[0175] The apparatus 400 may also comprise a control unit (or regulator unit) 418 which may, for example, be part of a computer system 420. The apparatus 400, in one example, may be configured such that the computer system 420 and/or the control unit 418 controls the process parameters of the methods disclosed herein. This configuration can enable controlled or automated implementation of the methods according to the invention specified herein, for example without manual interventions. This configuration of the apparatus 400 can be achieved or enabled, for example, via the computer program according to the invention as described herein.

[0176] FIG. 5 shows a schematic of a cross section through a pattern element of a lithography object, wherein the pattern element can be processed by an illustrative method of the invention. For example, by means of the method in the first aspect, it is possible to remove the three layers 1, 2, 3 of the pattern element locally in the working region.

[0177] An illustrative configuration may, for example, be as follows: The first layer 1 of the pattern element may comprise the first (ruthenium-containing) material (as described herein). A second layer 2 of the pattern element may comprise here the second (tantalum-containing) material (as described herein). A third layer 3 of the pattern element may comprise here the further (tantalum-containing) material (as described herein). The second layer may, for example, be formed from tantalum boroxide (e.g. TaBO) or comprise said material and/or the third layer may, for example, be formed from tantalum boronitride (e.g. TaBN) or comprise said material. It should be mentioned that the layer thicknesses of the first, second and/or third layers of the pattern element are shown merely schematically in FIG. 5. Thus, in one example, the layer thickness of the second layer may also be less than the layer thickness of the first and/or second layer (although other geometric variations are also conceivable). The local removing of at least one of the three layers described herein need not (necessarily) be restricted here to a particular layer thickness sequence of the three layers.

[0178] FIG. 5 likewise shows the capping layer D, the reflective layer stack ML and the substrate of the lithography object. The object of FIG. 5 may, for example, be a mask for EUV lithography. For example, the mask may comprise a phase-shifting EUV mask and/or an (essentially) radiation-absorbing EUV mask. The pattern element with the first, second and third layers 1, 2, 3 may be designed here to be correspondingly phase-shifting and/or radiation-absorbing for EUV lithography.

[0179] For example, in the case of a defect in the mask, excess material of a layer of the pattern element may be removed in one example of the method described herein. The defect may, for example, be an opaque defect. For the removing of the first layer 1 in the working region, it is possible here to use xenon difluoride with water as first process gas (as described herein). For the removing of the second and/or third layer, it is possible to use xenon difluoride with nitrogen dioxide and tetraethyl orthosilicate as second process gas (as described herein). The capping layer D may comprise ruthenium here. The capping layer D may function here as etch stop in the removing of the second and/or third layer.

[0180] Further examples of the invention may be as follows:

[0181] Example 1: Method of processing a lithography object, comprising: [0182] providing a first process gas; [0183] providing a particle beam in a working region of the object for removal of a first material (1) in the working region based at least partly on the first process gas; [0184] wherein the first material (1) comprises ruthenium.

[0185] Example 2: Method according to Example 1, wherein the first process gas comprises xenon difluoride molecules.

[0186] Example 3: Method according to Example 1 or 2, wherein the first process gas comprises water molecules.

[0187] Example 4: Method according to any of Examples 1-3, wherein the method further comprises: [0188] providing a second process gas; [0189] providing the particle beam in the working region for removal of a second material (2) in the working region based at least partly on the second process gas; [0190] wherein the second material (2) comprises tantalum.

[0191] Example 5: Method according to Example 4, wherein the second process gas comprises xenon difluoride molecules.

[0192] Example 6: Method according to Example 4 or 5, wherein the second process gas comprises nitrogen dioxide molecules.

[0193] Example 7: Method according to any of Examples 4-6, wherein the second process gas comprises tetraethyl orthosilicate molecules.

[0194] Example 8: Method according to any of Examples 4-7, wherein the method further comprises: [0195] providing the particle beam in the working region for removal of a further material (3) in the working region based at least partly on the second process gas: [0196] wherein the further material (3) comprises tantalum; [0197] wherein the further material (3) has a different material composition from the second material (2).

[0198] Example 9: Method according to Example 8, wherein the molar proportion of tantalum in the further material (3) is higher or essentially the same compared to a molar proportion of another element included in the further material.

[0199] Example 10: Method according to either of Examples 8 and 9, wherein the further material (3) comprises at least one of the following: tantalum oxide, tantalum boroxide, tantalum nitride, tantalum boronitride.

[0200] Example 11: Method according to any of Examples 1-10, wherein the molar proportion of ruthenium in the first material (1) is higher or essentially the same compared to a molar proportion of another element included in the first material.

[0201] Example 12: Method according to any of Examples 4-11, wherein the molar proportion of tantalum in the second material (2) is higher or essentially the same compared to a molar proportion of another element included in the second material.

[0202] Example 13: Method according to any of Examples 4-12, wherein the second material (2) further comprises oxygen, boron and/or nitrogen.

[0203] Example 14: Method according to any of Examples 4-13, wherein the second material (2) comprises at least one of the following: tantalum oxide, tantalum boroxide, tantalum nitride, tantalum boronitride.

[0204] Example 15: Method according to any of Examples 1-14, wherein the particle beam comprises an electron beam.

[0205] Example 16: Method according to any of Examples 1-15, further comprising: [0206] determining an endpoint of a removing of a material based at least partly on detecting of electrons that are released from the object.

[0207] Example 17: Method according to any of Examples 1-16, wherein a material is removed at least partly over a predetermined period of time.

[0208] Example 18: Method according to any of Examples 1-17, wherein the material removed comprises a layer material of a pattern element of the object.

[0209] Example 19: Method according to any of Examples 1-18, wherein the method is effected in such a way that a defect of the object is repaired.

[0210] Example 20: Method according to any of Examples 1-19, wherein the object comprises a mask for EUV lithography.

[0211] Example 21: Apparatus (400) for processing a lithography object, comprising: [0212] means of providing a first process gas; [0213] means of providing a particle beam in a working region of the object, wherein the apparatus is configured to perform a method according to any of Examples 1 to 20.

[0214] Example 22: Computer program comprising instructions which, when executed by a computer system, cause the computer system and/or an apparatus according to Example 21 to implement a method according to any of Examples 1 to 20.

[0215] In some implementations, the control unit 418 and/or the computer system 420 can include one or more data processors configured to execute one or more computer programs that include a plurality of instructions according to the principles described above. The control unit 418 and/or the computer system 420 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 control unit and/or the computer system cause the control unit and/or computer system to carry out the processes. The computer system 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. In some implementations, the control unit and/or the computer system can include digital electronic circuitry, computer hardware, firmware, software, or any combination of the above. The features related to processing of data 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 method steps can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations. Alternatively or in 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.

[0216] 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.

[0217] For example, the computer system 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 a computer system include one or more processors for executing instructions and one or more storage area devices for storing instructions and data. Generally, a computer system 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, flash storage devices, and solid state drives; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM, DVD-ROM, and/or Blu-ray discs.

[0218] In some implementations, the processes described above 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, grid, or cloud), 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.

[0219] In some implementations, the software may be provided on a medium, such as CD-ROM, DVD-ROM, Blu-ray disc, a solid state drive, or a hard 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.