DE102020201482A1 - Apparatus and method for repairing a defect of an optical component for the extreme ultraviolet wavelength range - Google Patents

Abstract

The present invention relates to a device (700) for repairing at least one defect (150, 350, 550, 1450) of an optical component (100, 300, 500) for the extreme ultraviolet (EUV) wavelength range, the optical component (100, 300, 500 ) comprises a substrate (110) and a multilayer structure (120) arranged on the substrate (110), and wherein the device comprises: (a) at least one light source (610, 1010, 1020) which is formed, a photon beam (605, 1030, 1130) in the EUV wavelength range and / or in the wavelength range of soft X-rays; and (b) wherein the at least one light source (605, 1030, 1130) is further designed to repair the at least one defect (150, 350, 550, 1450) by locally changing the optical component (100, 300, 500) .

Description

Technical area

The present invention relates to a device and a method for repairing at least one defect of an optical component for the extreme ultraviolet (EUV) wavelength range, the optical component for the EUV wavelength range comprising a substrate and a multilayer structure arranged on the substrate.

State of the art

As a result of the growing integration density in the semiconductor industry, photolithography masks have to depict increasingly smaller structures on wafers. On the photolithography side, the trend of increasing integration density is taken into account by shifting the exposure wavelength of photolithography devices to ever smaller wavelengths. In photolithography devices or lithography devices, an ArF (argon fluoride) excimer laser is currently often used as a light source, which emits at a wavelength of about 193 nm.

Lithography systems are currently under development that use electromagnetic radiation in the EUV (extreme ultraviolet) wavelength range (preferably in the range of 10 nm to 15 nm). These EUV lithography systems are based on a completely new beam guidance concept that uses reflective optical elements, since there are currently no materials available that are optically transparent in the specified EUV range. The technological challenges in the development of EUV systems are enormous and huge development efforts are necessary to bring these systems to industrial readiness.

The photolithographic masks, exposure masks, photo masks or simply masks play a decisive role in the imaging of ever smaller structures in the photoresist arranged on a wafer. With every further increase in the integration density, it becomes increasingly important to reduce the minimum feature size of the exposure masks. The manufacturing process of photolithographic masks is therefore becoming increasingly complex and thus more time-consuming and ultimately also more expensive. Due to the tiny structure sizes of the pattern elements, errors in mask production cannot be ruled out. These have to be repaired whenever possible.

The repair of mask defects is currently often carried out by means of electron beam-induced local deposition and / or etching processes. The following examples of documents deal with the repair of EUV masks: L. Pang et al .: “Compensation of EUV multilayer defects within arbitrary layout by absorber pattern modification”, in “Extreme Ultraviolet Lithography”, edited by BM Fontaine and PP Naulleau, Proc. of SPIE Vol. 7969, 79691E-1 - 79691E-14 ; WO 2016/037851 A1 ; M. Waiblinger et al .: “The door opener for EUV mask repair”, in “Photomask and Next Generation Lithography Mask Technology XIV”, edited by K. Kato, Proc. of SPIE, Vol. 84441, 8,4,41oF-1 - 84410F-10 ; WO 2011/161 243 A1 ; WO 2013/010 976 A1 ; WO 2015/144 700 A1 ; G. McIntyre et al .: “Through-focus EUV multilayer defect repair with micromachining”, in “Extreme Ultraviolet (EUV) Lithography IV, edited by PP Naulleau, Proc. of SPIE, Vol. 8679, 867911-1-867911-4 .

Due to the decreasing structure sizes of the pattern elements, controlling the local deposition and etching processes is becoming more and more challenging. In addition, the repair strategies must be individually adapted to the requirements of the individual production environments. Every technology-driven adaptation of the EUV masks (for example their material composition, dimensions or structure) requires a reassessment of the established repair processes, which in some cases leads to their time-consuming redesign.

The following exemplary documents describe coherent light sources for the EUV wavelength range: S. Hädrich et al .: "High photon flux tabletop coherent extreme ultraviolet source", DOI: 10.1038 / nphoton.2014.214, arXiv: 1403.4631 ; https: jjkmlabs.comjwp-contentjuploadsj2017 j 02jKML_XUUSTM.pdf; H. Carstens et al .: "High-harmonic generation at 250 MHz with photon energies exceeding 100 eV", Optica, Vol. 3, No. 4 / April 2016, pp. 366-369, Nature Photonics, Vol. 8, pp. 779-783 (2014) .

In the article "Understanding thin film laser ablation: The role of the effective penetration depth and film thickness", Physics Procedia, Vol 56, pp. 1007-1014 (2014) investigate the authors M. Domke et al. the removal of a thin metal layer from an optically transparent material with the help of laser pulses. The authors J. Na et al. describe in the article "Application of actinic mask review system for the preparation of HVM EUV lithography with defect free mask", BACUS, Vol. 33, July 2017, pp. 1-8 , examining an EUV mask with an HHG (High Harmonic Generation) laser system.

The present invention is based on the problem of specifying a device and a method which make it possible to repair Improve defects in optical components for the extreme ultraviolet wavelength range.

Summary of the invention

According to an embodiment of the present invention, this problem is solved by an apparatus according to claim 1 and a method according to claim 15. In one embodiment, the device for repairing at least one defect of an optical component for the extreme ultraviolet (EUV) wavelength range, wherein the optical component comprises a substrate and a multilayer structure arranged on the substrate, has: (a) at least one light source which is formed to generate a photon beam in the EUV wavelength range and / or in the wavelength range of soft X-rays; and (b) wherein the at least one light source is further designed to repair the at least one defect by locally changing the optical component.

The inventive device represents a paradigm shift in the repair of components for the EUV wavelength range. In the previous indirect processes, an electron beam activates a local deposition process to deposit missing material or a local etching process to remove excess material by providing a precursor gas Reaction site. A device according to the invention, on the other hand, uses a photon beam in the EUV wavelength range and / or in the wavelength range of soft X-rays in order to repair a defect directly. As a result, a device according to the invention overcomes the lateral resolution limitation of conventional repair devices, which is brought about by the use of a precursor gas. Due to the small wavelength of electromagnetic radiation in the EUV range, a device according to the invention advances into new dimensions of lateral spatial resolution in the repair of defects in optical components for the EUV wavelength range. In addition, contamination of the optical component with a defect repair by a precursor gas and / or its constituents is avoided.

The EUV spectral range covers wavelengths from 10 nm to 121 nm. This corresponds to photon energies between 10.3 eV (electron volts) and 124 eV. In this application, the range of soft X-rays is understood to mean the wavelength range from 0.1 nm to 10 nm. The associated photon energies extend over the range from 124 eV to 12.4 keV. The actinic wavelength, i.e. the wavelength at which the optical component is operated, preferably comprises the wavelength range from 10 nm to 15 nm or the energy range from 124 eV to 82.7 eV.

The at least one light source can generate a photon beam with a wavelength in the range of the actinic wavelength.

On the one hand, a focused photon beam in the range of the actinic wavelength has a high lateral spatial resolution, which enables a very precise repair of a defect to be carried out and at the same time reduces the risk of damage to the optical component during the repair process. On the other hand, a light source that generates a photon beam in the range of the actinic wavelength can be used to take an aerial photo of a defective area and / or a repaired area.

The local change in the optical component can include a local change in a reflectivity of the optical component in the range of an actinic wavelength.

Defects in a reflective optical component for the EUV wavelength range typically manifest themselves in an uneven distribution of the reflected optical intensity. There may be areas of the optical component from which more or less light, as intended by the design, is reflected. By using the EUV photon beam to locally change the reflectivity of the optical component, the uneven distribution of the optical intensity reflected by the optical component can be eliminated or at least significantly reduced.

The local modification of the optical component can include a local removal of material from the optical component with the photon beam.

The material is removed from the optical component by evaporation with the aid of the photon beam. In order to evaporate material, it has to be heated to the material-specific evaporation temperature, for which an amount of energy is necessary that is dependent on the density and the heat capacity of the material. On the other hand, the material-specific heat of vaporization must be made available to the material. A focused EUV photon beam can locally apply these specific energy densities, i.e. energy per volume. This is essentially due to two properties of an EUV photon beam. On the one hand, this can be focused on a very small diffraction-limited area and, on the other hand, pulses of EUV photon beams in the sub-femtosecond range can be generated, which have a very high power density.

An optical component can comprise a photolithographic mask for the EUV wavelength range or a mirror for the EUV wavelength range.

The local removal of material can comprise at least one element from the group: removing excess material of at least one element of an absorber pattern of a photolithographic mask, removing material from the multilayer structure of the optical component, and removing at least one particle from the optical component.

The light source of a device according to the invention enables both the repair or correction of defects in excess material and defects in missing material. A defect of missing absorber material in one or more pattern elements of a photolithographic mask is compensated for by locally removing part of the multilayer structure. As a result, essentially no more photons are reflected from the processed part of the photolithographic mask and the repaired area cannot be distinguished from a defect-free area in an aerial image or in an image in a photoresist.

Using the same principle, an uneven reflection of an EUV mirror can be repaired. In addition, a particle present on the optical component, which is visible in an aerial image of the optical component, can be removed from a surface of the optical component by evaporation by means of a focused EUV photon beam.

The term “essentially” means here, as in other places in the present application, a measurement of a physical variable within its error limits when measuring devices according to the prior art are used for the measurement.

The at least one light source can furthermore be designed to set an energy density of the photon beam for repairing the at least one defect of the optical component.

The energy density of the photon beam can be adjusted by at least two parameters. On the one hand, the focus condition and thereby the spot size with which the photon beam of the light source strikes the defect or the optical component can be set. On the other hand, the average power and thus also the pulse power of the photon beam can be varied.

The device according to the invention can furthermore have a detector for detecting photons reflected by the optical component, and / or an energy sensor for detecting photons reflected by the optical component and / or the at least one defect during a repair for monitoring the repair.

If the device has a detector, this can be used before, during and after a repair process of a defect in order to examine the effect of the defect or of a remaining defect part. In particular, the detector can be used in combination with the photon beam to check the success of a defect repair.

An energy sensor can be used to detect photons reflected from the repaired site during a repair process and thereby determine a change in the photon flux density, in particular a decrease in the photon flux density during the repair process.

The detector can comprise a CCD (Charge Coupled Device) camera for the EUV wavelength range. The energy sensor can be an element of a detector element of a CCD camera.

Furthermore, the device according to the invention can comprise an energy-dispersive X-ray detector. The energy dispersive X-ray detector can detect photons generated by the optical component and / or the defect of the optical component as a result of the irradiation with the photon beam. This makes it possible to determine a material composition, the material that the photon beam processes.

The device according to the invention can be designed to operate the at least one light source and the energy sensor in a closed feedback loop.

This makes it possible to monitor a repair process in real time. The likelihood of a repair operation failing can be significantly reduced. In particular, damage to the optical component can be largely prevented, since it can be determined in real time whether the material of a defect or the optical component is being removed.

The device according to the invention can furthermore have at least one first mirror for scanning the photon beam over the at least one defect of the optical component, and can have at least one second mirror for directing the photon beam onto a region of the optical component that includes the at least one defect.

An embodiment of the device according to the invention with two mirrors makes it easier to switch the device from an examination mode of the optical component or the defect of the optical component to a repair mode for repairing the defect and vice versa.

The at least one first mirror can be designed to focus the photon beam on the at least one defect in the optical component. Furthermore, the at least one first mirror can be designed to scan the focused photon beam over the optical component and / or the at least one defect in the optical component.

The at least one light source can be designed to generate a coherent photon beam in the EUV wavelength range and / or in the wavelength range of soft X-ray radiation.

The at least one light source can comprise a high harmonic generation (HHG) laser. The spectrum of high harmonics of a focused femtosecond laser system extends into the EUV wavelength range and sometimes beyond into the even shorter-wave spectral range. An HHG laser generates ultrashort EUV or X-ray pulses with a small beam divergence.

A photon beam can have a spot diameter of 0.5 nm to 200 nm, preferably 1 nm to 100 nm, more preferably 1 nm to 50 nm, and most preferably 1 nm to 20 nm. The spot diameter denotes the FWHM (Full Width Half Maximum) half-value width of the photon beam.

A photon beam can comprise pulses with a pulse length in the range from 0.5 fs to 200 fs, preferably 1 fs to 100 fs, more preferably 2 fs to 50 fs and most preferably from 3 fs to 30 fs. The abbreviation “fs” stands for femtosecond.

The pulses of the photon beam can have a pulse power in the range from 0.5 nW to 2 nW, preferably 0.2 nW to 5 nW, more preferably 0.1 nW to 10 nW, and most preferably 0.05 nW to 20 nW.

The device according to the invention can furthermore have a control device which is designed to move the at least one first mirror and / or the at least one second mirror over a macroscopic distance.

By bringing the at least one first or the at least one second mirror into the photon beam of the at least one light source, it is possible to switch back and forth between the repair mode and the examination mode without moving the optical component.

The device according to the invention can comprise a Fresnel zone plate and / or the control device can be designed to move the Fresnel zone plate into and out of the photon beam.

In a second embodiment, the device defined above has a Fresnel zone plate which makes it possible to switch between a repair mode and an examination mode.

The control device can also be designed to configure the device for an examination mode with the photon beam, and / or the control device can also be designed to switch the device between the examination mode and a repair mode.

It is a decisive advantage of a device according to the invention that on the one hand it enables an examination of the optical component or a defect of the optical component and on the other hand allows the defect to be repaired without moving the optical component from the repair tool to a review tool and thus needs to be realigned. In addition, the transport of the optical component from a first tool to a second tool typically causes the vacuum to be broken, which additionally slows down the process sequence. For the reasons mentioned, a device according to the invention drastically accelerates a repair process compared to the prior art.

The device according to the invention can furthermore have a sample holder for fixing the optical component, which is designed to rotate the optical component about at least one axis, and / or the sample holder can furthermore be designed to displace the optical component in at least one lateral direction in order to to examine a substantially defect-free area of the optical component with the photon beam.

The repair of a defect can be carried out by a substantially perpendicular incidence of the photon beam on the optical component. To examine the optical component, for example to check the success of the repair process, it is necessary for the photon beam to strike the optical component at the angle with respect to the normal direction that is provided for by the design. This condition can be established by rotating the optical component. This allows the Examination mode, the best possible aerial image of the repaired area of the optical component can be obtained.

In an alternative embodiment of the second embodiment, instead of the optical component, at least one mirror of the device is moved in order to meet the Bragg condition for the optical component.

The at least one light source can comprise a first light source which is designed to scan a focused photon beam over the at least one defect in order to repair the at least one defect, and can comprise a second light source which is designed to apply a photon beam to the area of the optical component to judge, which includes at least the at least one defect.

In a third embodiment, a device according to the invention comprises two separate light sources which are optimized for their respective task. The arrangement of the two light sources can be selected so that no parts have to be moved over macroscopic distances to switch between a repair mode and an examination mode.

The first and the second light source can generate a photon beam in the actinic wavelength range of the optical component. The first light source can generate a photon beam outside the actinic wavelength range and the second light source can generate a photon beam within the actinic wavelength range.

During the repair and / or during an examination, the optical component can comprise a pellicle through which the photon beam shines.

It is an advantage of a device according to the invention that it can carry out both a repair process and an examination process for the optical component in which the optical component has a pellicle. As a result, a defect is examined as it manifests itself in the operation of the optical component. Furthermore, the repair process is carried out under real-life conditions of the optical component. Another advantage is that repairs can be carried out through a pellicle, the pellicle remaining fully functional after the repair process has ended and therefore does not have to be replaced. In addition, a pellicle mounted on an optical component prevents the material removed from the optical component from precipitating in the device or at remote locations on the optical component and thereby contaminating it.

A method for repairing at least one defect of an optical component for the extreme ultraviolet (EUV) wavelength range, wherein the optical component comprises a substrate and a multilayer structure arranged on the substrate, has the steps: (a) generating a photon beam in the EUV wavelength range and / or in the wavelength range of soft X-rays; and (b) adjusting the photon beam so that the at least one defect is repaired by locally changing the optical component.

The adjustment of the photon beam can comprise at least one element from the group: focusing the photon beam, changing a pulse power of the photon beam, changing a polarization of the photon beam, and changing an angle of incidence of the photon beam with respect to a normal direction of the optical component.

The method according to the invention can furthermore have the step: switching between repairing the at least one defect in the optical component with the photon beam and examining the optical component and / or the at least one defect in the optical component with the photon beam.

1. (a) Untersuchen des zumindest einen Defekts mit dem Photonenstrahl, und/oder Untersuchen einer im Wesentlichen defektfreien Referenzposition mit dem Photonenstrahl; (b) Bestimmen einer Reparaturform für den zumindest einen untersuchten Defekt, falls der zumindest eine untersuchte Defekt eine vorgegebene Schwelle übersteigt; (c) Reparieren des zumindest einen Defekts mit dem Photonenstrahl; (d) Untersuchen einer reparierten Stelle der optischen Komponente mit dem Photonenstrahl; und (e) Wiederholen der Schritte a. und b., falls ein verbleibender Rest des zumindest einen Defekts die vorgegebene Schwelle übersteigt.

The method according to the invention can furthermore have at least one of the steps:

1. (a) examining the at least one defect with the photon beam, and / or examining a substantially defect-free reference position with the photon beam; (b) determining a form of repair for the at least one examined defect if the at least one examined defect exceeds a predetermined threshold; (c) repairing the at least one defect with the photon beam; (d) examining a repaired location of the optical component with the photon beam; and (e) repeating steps a. and b. if a remaining remainder of the at least one defect exceeds the predetermined threshold.

The device according to one of the aspects described above can be designed to carry out the method steps of one of the methods specified above.

Finally, a computer program comprises instructions which, when they are executed by a computer system, cause the computer system to carry out the method steps of the aspects described above.

Figure list

• 1 im oberen Teilbild schematisch einen Ausschnitt eines Schnitts einer Seitenansicht einer Maske für den extrem ultravioletten Wellenlängenbereich (EUV) zeigt, mit einem Pattern-Element, das einen Defekt inForm überschüssigen Absorber-Materials aufweist, und im unteren Teilbild eine Aufsicht auf die Seitenansicht des oberen Teilbildes wiedergibt;
• 2 schematisch die Änderung der normierten Intensität während der Reparatur des Defekts überschüssigen Absorber-Materials der EUV-Maske der 1 veranschaulicht;
• 3 im oberen Teilbild schematisch einen Ausschnitt eines Schnitts einer Seitenansicht eine EUV-Maske darstellt, mit einem Pattern-Element, das einen Defekt inForm fehlenden Absorber-Materials aufweist, und im unteren Teilbild eine Aufsicht auf die Seitenansicht des oberen Teilbildes präsentiert;
• 4 schematisch die Änderung der normierten Intensität während der Reparatur des Defekts fehlenden Absorber-Materials der EUV-Maske der 3 veranschaulicht;
• 5 im oberen Teilbild schematisch einen Ausschnitt eines Schnitts einer Seitenansicht eine EUV-Maske zeigt, die einen Defekt inForm eines Partikels aufweist, und im unteren Teilbild eine Aufsicht auf die Seitenansicht des oberen Teilbildes wiedergibt;
• 6 schematisch einen Schnitt durch eine EUV-Maske mit einem Defekt und ein erstes Ausführungsbeispiel einer Vorrichtung zur Reparatur des Defekts präsentiert, wobei die Vorrichtung im Reparaturmodus arbeitet;
• 7 die 6 reproduziert, wobei jedoch die Vorrichtung im Untersuchungsmodus arbeitet;
• 8 die EUV-Maske der 6 mit einem zweiten Aufführungsbeispiel der Vorrichtung zur Reparatur des Defekts darstellt, wobei die Vorrichtung im Reparaturmodus arbeitet;
• 9 die 8 reproduziert, wobei jedoch die Vorrichtung im Untersuchungsmodus betrieben wird;
• 10 die EUV-Maske der 6 mit einem dritten Aufführungsbeispiel der Vorrichtung zur Reparatur des Defekts wiedergibt, wobei die Vorrichtung im Reparaturmodus arbeitet;
• 11 die 10 reproduziert, wobei jedoch die Vorrichtung im Untersuchungsmodus arbeitet;
• 12 die Vorrichtung der 10 und 11 wiedergibt, wobei die Vorrichtung gleichzeitig im Reparaturmodus und im Untersuchungsmodus arbeitet;
• 13 die Konfiguration der 6 zeigt, wobei während des Reparaturprozesse ein Pellikel auf die EUV-Maske montiert ist;
• 14 im linken Teilbild eine Streifenstruktur einer EUV-Maske mit einem Defekt und rechten Teilbild eine defektfreie Referenz-Streifenstruktur präsentiert, wobei beide Teilbilder mit EUV-AIMS™ aufgenommen wurden;
• 15 in den oberen Teilbildern die Streifenstrukturen der EUV-Maske der Teilbilder der 14 darstellt, wie diese in Bildern erscheinen, die eine Reparaturvorrichtung im Untersuchungsmodus erzeugt, das untere linke Teilbild das obere linke Teilbild nach Abschluss des Defektreparaturprozesses präsentiert und das untere rechte Teilbild die Referenz-Streifenstruktur des oberen rechten Teilbildes reproduziert;
• 16 die Bilder der 14 nach der Defektreparatur wiedergibt;
• 17 ein Flussdiagramm einen Reparaturprozess einer optischen Komponente für den EUV-Wellenlängenbereich zeigt; und
• 18 ein Flussdiagramm eines erfindungsgemäßen Verfahrens zum Reparieren eines Defekts einer optischen Komponente für den EUV-Wellenlängenbereich darstellt.

In the following detailed description, presently preferred embodiments of the Invention described with reference to the drawings, wherein

• 1 in the upper part schematically shows a section of a section of a side view of a mask for the extreme ultraviolet wavelength range (EUV), with a pattern element that has a defect in the form of excess absorber material, and in the lower part a plan view of the side view of the upper part reproduces;
• 2 schematically the change in the normalized intensity during the repair of the defect of the excess absorber material of the EUV mask 1 illustrates;
• 3 in the upper part schematically shows a detail of a section of a side view of an EUV mask, with a pattern element which has a defect in the form of missing absorber material, and in the lower part a plan view of the side view of the upper part is presented;
• 4th schematically the change in the normalized intensity during the repair of the defect of the missing absorber material of the EUV mask 3 illustrates;
• 5 in the upper partial image schematically shows a detail of a section of a side view of an EUV mask which has a defect in the form of a particle, and in the lower partial image shows a plan view of the side view of the upper partial image;
• 6th schematically presents a section through an EUV mask with a defect and a first exemplary embodiment of a device for repairing the defect, the device operating in repair mode;
• 7th the 6th reproduced, but with the device operating in examination mode;
• 8th the EUV mask of the 6th with a second embodiment of the device for repairing the defect, the device operating in the repair mode;
• 9 the 8th reproduced, but the device is operated in the examination mode;
• 10 the EUV mask of the 6th with a third embodiment of the device for repairing the defect, the device operating in the repair mode;
• 11 the 10 reproduced, but with the device operating in examination mode;
• 12th the device of the 10 and 11 reproduces, the device operating simultaneously in repair mode and examination mode;
• 13th the configuration of the 6th shows, wherein a pellicle is mounted on the EUV mask during the repair process;
• 14th the left partial image shows a stripe structure of an EUV mask with a defect and the right partial image shows a defect-free reference stripe structure, both partial images being recorded with EUV-AIMS ™;
• 15th in the upper partial images the stripe structures of the EUV mask of the partial images of the 14th illustrates how these appear in images generated by a repair device in the examination mode, the lower left partial image presents the upper left partial image after the defect repair process has been completed and the lower right partial image reproduces the reference stripe structure of the upper right partial image;
• 16 the pictures of the 14th reproduces after defect repair;
• 17th a flowchart shows a repair process of an optical component for the EUV wavelength range; and
• 18th represents a flow diagram of a method according to the invention for repairing a defect of an optical component for the EUV wavelength range.

Detailed description of preferred exemplary embodiments

In the following, currently preferred embodiments of a device according to the invention and of a method according to the invention for repairing one or more defects in a photographic mask for the extreme ultraviolet (EUV) wavelength range are explained in more detail. However, the device according to the invention and the method according to the invention are not restricted to the examples discussed below. Rather, they can generally be used to repair defects in optical components for the extreme ultraviolet (EUV) wavelength range. Examples of optical components for the EUV wavelength range are, in addition to EUV photo masks, also EUV mirrors, i.e. mirrors for the EUV wavelength range.

the 1 presented schematically in the upper part of the picture 105 a side view of a section of a photolithographic mask 100 for the EUV wavelength range. A photolithographic mask 100 for the EUV wavelength range, the EUV mask is also used below 100 or EUV photo mask 100 called. The exemplary EUV mask 100 the 1 is for one Exposure wavelength designed in the range of 13.5 nm. The EUV mask 100 has a substrate 110 made of a material with a low coefficient of thermal expansion, such as quartz. Other dielectrics, glass materials or semiconducting materials can also be used as substrates for EUV masks, such as ZERODUR ^® , ULE ^® or CLEARCERAM ^® . The back or the back surface of the substrate 110 the EUV mask 100 serves to hold the substrate 110 during the manufacture of the EUV mask 100 and during their operation in an EUV photolithography device. On the back of the substrate 110 a thin electrically conductive layer for holding the substrate on an electrostatic suction device (English: electrostatic chuck (ESC)) is preferably applied (in the 1 not shown). In an alternative embodiment, the EUV mask 100 no electrically conductive layer on the back of the mask substrate 110 on and the EUV mask 100 is fixed with the aid of a vacuum chuck (VC) during its operation in an EUV photolithography device.

On the front of the substrate 110 becomes a multilayer film or structure 120 deposited, which comprises 20 to 80 pairs of alternating molybdenum (Mo) and silicon (Si) layers, which are also referred to below as MoSi layers. The thickness of the Mo layers is 4.15 nm and the Si layers have a thickness of 2.80 nm. To the multilayer structure 120 to protect it becomes a top layer 130 , for example made of silicon dioxide, typically applied with a thickness of about 7 nm on the top silicon layer. Other materials such as ruthenium (Ru) can also be used to form a top layer 130 can be used. Instead of molybdenum, layers made of other elements with a high number of nucleons, such as cobalt (Co), nickel (Ni), tungsten (W), rhenium (Re), zirconium (Zn) or iridium (Ir), can also be used for the MoSi layers become. The deposition of the multilayer structure 270 can be done for example by ion beam deposition (IBD, Ion Beam Deposition).

On the top layer 130 the EUV mask 100 an absorption layer is deposited. For the absorption layer 250 suitable materials include Cr, titanium nitride (TiN) and / or tantalum nitride (TaN). An anti-reflective layer, for example made of tantalum oxynitride (TaON) (in FIG 1 not shown). The absorption layer is structured, for example, with the aid of an electron beam or a laser beam, so that a structure of absorbing pattern elements is generated from the absorption layer over the entire area. In the excerpt of the 1 is a pattern element 140 shown, which is wider than intended by the design. The excess material 150 is a defect 150 the EUV mask 100 . Because of the defect 100 are made from the area of excess material 150 no or at least very much fewer EUV photons reflected than intended by the design.

The defect 150 Excess absorber material can be removed with the help of an EUV laser beam 160 or an EUV photon beam 160 removed. An EUV photon beam can be generated, for example, by focusing ultra-short pulses from a pump laser and exposing them to a gas flow in the focus or in the vicinity of the focus. A titanium: sapphire laser, for example, can be used as the pump laser, which preferably emits femto-tilt light pulses at a wavelength of 800 nm. As gases for generating EUV photon beams 160 Noble gases such as krypton or xenon are currently preferred. From a two-dimensional power density of about 10 ¹⁴ W / cm ² or a photon flux density of about 10 ¹⁴ J / (cm ² -s) of the pumping laser beam generated in the gas stream high harmonics. The generation of high harmonics is referred to in the field as High Harmonic Generation (HHG). At the extremely high intensities specified above, the electric field of the pump beam reaches a field strength that is comparable to the electric field in individual atoms. The internal atomic electric field is deformed or disturbed by the electric field in the focus of the pump laser beam in such a way that electrons can overcome the bond to the atom and tunnel into the continuum. The free electrons are then accelerated in the laser field by absorbing several or many (up to several hundred) photons. When the sign of the electric laser field changes, part of the electrons in the electric field of the atom from which the electron originates is slowed down and releases its energy in the form of a high-energy or a few high-energy photons. The highest photon energy that can be generated with this principle is limited by the maximum number of photons absorbed by an electron in the acceleration phase. During an oscillation period of the pump laser light, two coherent ultra-short sub-femtosecond pulses with a small beam divergence are generated.

From the multitude of harmonics generated, an EUV spectrometer can be used to select a harmonic that lies in the actinic wavelength range or comes closest to the actinic wavelength range. At present, HHG laser systems in the actinic wavelength range achieve an average power of around 1 µW, which corresponds to a photon flow of around 7 · 10 ¹⁰ photons / s with an assumed photon energy of 100 eV per photon.

It is now assumed that 10% of the EUV photons can be concentrated in a spot diameter of 100 nm. This corresponds to a photon flux density of approximately 7 · 10 ⁶ photons / (nm ² · s). This corresponds to an energy flux density of about 10 ³ J / cm ² and is thus very clearly above the threshold energy density for femtosecond laser pulses. As already stated above, two intensifying factors contribute to the enormous energy flux density of a photon beam from an EUV laser, for example an HHG laser system. On the one hand, the EUV photons can be focused on small areas due to their very short wavelength. On the other hand, a single EUV photon carries a large amount of energy compared to a photon from the visible spectral range.

the authors KH Leitz et al. investigate in the article "Metal Ablation with Short and Ultrashort Laser Pulses", Physics Procedia 12 (011), pp. 230-238 ), the material removal with the help of microsecond, nanosecond, picosecond and femtosecond laser pulses. For femtosecond laser pulses, the authors give a threshold ^{energy density of 1.25 J / cm 2} for laser radiation in the vicinity of the visible spectral range.

The interaction zone of the EUV photon beam 160 is in the 1 by the reference number 170 . illustrated. The interaction of the photons of femtosecond pulses with matter can no longer be described by the classic ablation model, which takes into account the processes of heat conduction, melting, evaporation and plasma formation. The non-classical ablation model, which describes the ultrafast interaction between a photon beam and matter, is based on the assumption that when ultrashort laser pulses act on matter, the electrons or, in a metal, the electron gas are no longer in thermal equilibrium with the atomic cores. On a femtosecond time scale, the electron gas cannot deliver its energy instantaneously to the lattice of atomic cores. Under the action of femtosecond laser pulses, very high pressures, densities and temperatures are created locally, which affect the ionized material of the defect 150 accelerate to high speeds. Because of the short interaction time, the material of the defect 150 does not evaporate continuously, but is converted into the state of a superheated liquid. This fuses into a high-pressure mixture of liquid droplets and steam that spreads quickly. The liquid droplets are in the 1 by the reference number 180 illustrated.

The ultrashort pulses of the EUV photon beam 160 be about the defect 150 rasterized. One, several or many, for example several hundred, pulses can be applied to the same location of the defect 150 be directed before the photon beam 160 to a new position of the defect 150 is focused. To the defect 150 The photon beam can process better 160 and / or the EUV mask 100 can be tilted from the normal direction if necessary.

the 2 shows schematically the growth of the area of the defect 150 the EUV mask 100 reflected EUV photons. A point in the EUV mask is used as a reference 100 considered having an identical arrangement of pattern elements 140 has, but without a defective point 150 or a defective item 150 to have. The defective area of the EUV mask is at this reference position 100 based. By removing the excess absorber material from the defect 150 with the help of the EUV photon beam 160 from the top layer 130 the EUV mask is removed, the optical intensity reflected by the EUV mask increases locally. After the out of the area of the defect 150 reflected radiation that reaches the level of the reference range, the repair process is stopped by the EUV photon beam 160 switched off or interrupted.

Monitoring the repair process can be done in several ways. On the one hand, the optical intensity reflected from the defective area in the EUV wavelength range can be measured permanently by means of an energy sensor during the repair process. This is in the 2 illustrated. However, it is also possible to interrupt the repair process from time to time and, with the aid of a large-area EUV photon beam and a detector, the optical reflection from the area of the defect 150 to control. Finally, it is also possible to use an energy-dispersive X-ray detector to detect the defect during the repair process 150 to analyze generated X-ray photons in an energy-selective manner. This can reduce the material composition of the defect 150 can be analyzed and determined when the EUV photon beam 160 the top layer 130 reached the EUV mask.

The upper part of the picture 305 the 3 shows a side view of a section of an EUV mask 300 who have a defect 350 missing absorber material of a pattern element 340 having. The lower part of the picture 355 presents the associated supervision. The defect 350 is characterized in that it consists of an area of the EUV mask 300 EUV photons are reflected, which should appear dark. The defect 350 Missing absorber material can be repaired in different ways. On the one hand, the multilayer structure 120 below the defective area 350 with a focused EUV photon beam 360 be removed. This will ensure that out of the field of the defect 350 EUV photons can no longer be reflected. The reference number 370 illustrates the local interaction zone of the EUV photon beam 360 with the material of the multilayer structure 120 the EUV mask 300 .

To repair the defect 350 it may also be sufficient to have only part of the multilayer structure 120 in the area of the defect 350 to remove. Typically the top layers have a multilayer structure 120 most of them contribute to the reflection of EUV photons. It can also be used, especially for small-area defects 350 If the absorber material is missing, the surface of the multi-layer structure will be sufficient 120 to melt locally in the area of the defect, so that the evenness of the top layer 130 and optionally the top layers of the multilayer structure 120 are locally disturbed or destroyed.

Based on the 3 The repair process explained can also be used to repair a local excess optical intensity of a mirror for the EUV wavelength range (in the 3 not shown). A locally increased reflection of an EUV mirror can be caused by a defect in the multilayer structure 120 and / or the substrate 110 be effected.

the 4th schematically illustrates the change in the locally reflected optical intensity of the EUV mask 300 as a result of executing the in the 3 described repair process. The ones from the area of the defect 350 reflected intensity is similar to that in that 2 , to a defect-free area of the EUV mask 300 standardized with an identical pattern. Because of the defect 350 Missing absorber material is taken from an area of the EUV mask 300 EUV photons reflected, which should actually be dark. This leads to the defect 350 to a locally increased reflectivity of the EUV mask 300 . Repairing the defect 350 with the EUV photon beam 360 reduces the local excess of optical intensity. As soon as the radiation reflected from the area of the defect reaches the reference level, the EUV mask is repaired 300 completed.

The upper part of the picture 505 the 5 presents a side view of a section of a detail of an EUV mask 500 that have a particle 550 on the top layer 130 the multilayer structure 120 having. The lower part of the picture 555 again shows the associated supervision. The particle 550 shadows part of the multilayer structure 120 for incident EUV photons, which leads to the EUV mask 500 from the area of the defect 550 , ie of the particle 550 reflects fewer photons than from a defect-free reference area. The particle 550 can by means of the focused photon beam 560 from the top layer 130 the EUV mask 500 be removed. The reference number 570 again illustrates the transition zone of the EUV photon beam 560 with the particle 550 .

When removing a particle 550 it is advantageous to use an energy-dispersive X-ray detector during the ablation process in order to determine the material composition of the particle 550 to analyze in situ (in the 5 not shown). This can end the ablation process for the particle 550 be monitored. In addition, from the material composition of the particle 550 often its source can be tapped. If this succeeds, the source of the contamination can be eliminated or at least drastically reduced so that future repair operations can be avoided.

The diagram 695 the 6th shows a side view of a section of an EUV mask 600 . The EUV mask 600 can be one of the defective EUV masks 100 , 300 or 500 being. Ie the defect 650 the mask 600 can be one of the defects 150 , 350 or 550 his and the absorber pattern 640 can be one of the pattern elements 140 , 340 , 540 the EUV masks 100 , 300 or 500 include. Furthermore, the interaction zone 670 one of the interaction zones 170 , 370 , 570 being. It also illustrates the 6th a first embodiment of a device 700 to repair the defect 650 and to examine the EUV mask 600 or generally an optical component 100,300,500 for the EUV wavelength range.

the 6th schematically illustrates the partial process of repairing the defect 650 . The device 700 includes a light source 610 for the EUV wavelength range, which is a collimated EUV photon beam 605 generated. The device also has 700 a control device 750 . on that over the connection 710 with the EUV light source 610 connected is. The one from the EUV light source 610 generated EUV photon beam 605 is from a first imaging EUV mirror 620 on the defect 650 the EUV mask 600 focused. The first imaging EUV mirror 620 is about the connection 730 with the control device 750 . the device 700 connected.

The energy sensor 690 detected from the area of the defect 650 reflected EUV photons 680 while the focused EUV photon beam 630 from the control device 750 . about the defect 650 is rasterized. The energy sensor 660 is about the connection 720 also with the control device 750 . the device 700 connected. With the help of the energy sensor 690 can the control device 750 . the EUV laser system 610 or the EUV light source 610 in a closed Operate feedback loop. As in the 2 and 4th shown schematically, can be based on the energy sensor 690 as a function of the time detected change in the reflected optical intensity can be concluded on the progress of the defect removal.

the 7th shows schematically the execution of the sub-process of examining the EUV mask 600 for that in the 6th illustrated first embodiment by the device 700 . To examine the defective area 650 the EUV mask 600 moves the controller 750 . the device 700 the first imaging EUV mirror 620 from the collimated EUV photon beam 605 the EUV light source 610 . This allows the EUV photon beam 605 on the second imaging EUV mirror 650 hit. The second imaging EUV mirror 650 directs the EUV photon beam 605 as an expanded photon beam 760 on an area of the EUV mask 600 which includes the area containing the defect 650 contains. In the in the 6th and 7th The exemplary embodiment illustrated includes the defect 650 the particle 550 . The multilayer structure 120 EUV mask 600 reflects part of the incident EUV photons of the beam 760 towards the detector 780 . In the in the 7th The exemplary embodiment illustrated comprises the detector 780 a CCD camera.

the 8th presents a second embodiment of a device according to the invention 700 . The second exemplary embodiment is based on the example of repairing one of the defects 650 the EUV mask 600 explained. The device 700 to repair the defect 650 includes the EUV light source 610 of the first performance example. This in turn is over the connection 710 with the control device 750 . connected. The control device 750 . is also about the connection 810 with a non-imaging EUV mirror 820 , over the connection 855 with a Fresnel zone plate 850 and about the connection 865 with an energy sensor 680 associate. The EUV photon beam generated by the EUV light source 605 is from the EUV mirror 820 as an EUV photon beam 830 on the Fresnel zone plate 850 directed. The Fresnel zone plate 850 focuses the EUV photon beam passing through it 840 on the defect 650 the EUV mask 600 . That during the repair of the defective area 650 the EUV mask 600 reflected EUV light 860 is from the energy sensor 680 detected. On the basis of the EUV radiation detected by the energy sensor 860 can the control device 750 . the device 700 the EUV light source 610 , similar to the first embodiment, operate in a closed feedback loop (in the 8th not shown).

the 9 shows the second sub-process of the second exemplary embodiment, namely examining the EUV mask 600 with the EUV photon beam 605 the EUV light source 610 . For examining the EUV mask 600 drives the control device 600 the Fresnel zone plate 850 from the beam path of the EUV photon beam 920 . The photon beam that is no longer focused 830 hits in the area of the defect 650 the multilayer structure 120 the EUV mask 600 . So that the incident EUV photon beam 830 the Bragg reflection condition of the multilayer structure 120 the EUV mask 600 fulfilled as best as possible, causes the control device 750 . a rotation of the sample holder on which the EUV mask is placed 600 is arranged. The rotation of the EUV mask 600 is in the 9 by the reference number 910 illustrated. The sample holder (English: stage) is in the 9 not shown.

If - as in the 9 due to a remaining defect 650 symbolizes - a further repair step is necessary, the control device rotates 750 . the EUV mask 600 back to its starting position and guides the Fresnel zone plate 850 back into the beam path of the EUV photons 830 one, so that the repair of the remaining defect residue 650 can be continued.

The diagram 100 the 10 represents a third embodiment of the device according to the invention 700 The third embodiment of the 10 includes a first EUV light source 1010 and a second EUV light source 1020 both of which have connections 1015 and 1025 with the control device 750 . are connected. Furthermore, the control device 750 . with the detector 690 over the connection 695 connected. The third embodiment is also based on repairing the defects 650 the EUV mask 600 explained.

In the 10 is schematically the repair part of the third embodiment of the device according to the invention 700 reproduced. To repair the defect 650 the second EUV light source emits 1020 a focused photon beam 1030 on the defect 650 the EUV mask 600 or scans the focused photon beam 1030 about the defect 600 .

After a specified time, the repair process is interrupted and the treated or repaired area is interrupted 650 the EUV mask 600 Wil be inspected. For this purpose - as in the 11 shown schematically - the focused photon beam 1030 the second EUV light source stopped. Then the first EUV light source 1010 switched on, which is a collimated EUV photon beam 1130 on the area of the EUV mask 600 who directs the defect 650 contains. The area of the beam spot is chosen so large that the threshold density for the Melting the multilayer structure 120 the EUV mask 600 is not achieved. According to the estimation given above, this requires a spot diameter of about 5 µm or more.

In the 10 , 11 as well as the following 12th are the first EUV light source 1010 and the detector 690 so with regard to the normal direction of the EUV mask 600 arranged that the Bragg reflection condition for the actinic wavelength range of the EUV mask 600 is fulfilled in the best possible way. The third embodiment has the particular advantage of being able to switch between the repair mode and the examination mode of the device 700 no parts of the device 700 must be moved over macroscopic distances. The first EUV light source 1010 and the second EUV light source can be designed so that a single EUV light source has both the focused EUV photon beam 1030 as well as the EUV photon beam 1130 generated. In this embodiment, the first 1010 and the second EUV light source 1020 only a beam shaping device and / or a beam guiding device ready.

the 12th shows an embodiment of the device 700 where both light sources 1010 and 1020 at the same time photons 1030 and 1130 on the defect 650 or in an area around the defect 650 irradiate. In this exemplary embodiment, it is advantageous if the first EUV light source 1010 an EUV photon beam 1130 in the area of the actinic wavelength on the EUV mask 600 irradiates and the second EUV light source 1020 Photons outside the actinic wavelength range of the EUV mask 600 generated. This ensures that there are essentially no EUV photons from the second EUV light source 1020 on the detector 690 can get. This prevents corruption of the data from the detector 690 detected local reflected optical intensity.

the 13th reproduces the 6th with the difference that on the EUV mask 600 a pellicle 1310 is appropriate. The distance of the EUV pellicle 1310 from the deck view 130 the EUV mask is in the range of 2 to 3 mm. Both the repair process and the examination process of the EUV mask 600 occurs through the pellicle 1310 through. This makes it possible to reduce the impact of a defect 650 the EUV mask 600 below to examine the conditions that occur in real operation of the EUV mask 600 prevalence. Furthermore, the dismantling of the pellicle 1310 for correcting defects and reassembling the pellicle 1310 after the defect repair and the associated possible damage to the mask 600 be avoided.

Based on the 8th until 12th described repair processes and / or examination processes of the EUV mask 600 can also be done with a pellicle mounted on the EUV mask 1310 are executed.

Based on 14th until 16 below is the embedding of one with the device 700 executed repair process in the workflow of the defect analysis and defect correction of EUV masks 100 , 300 , 500 explained. Before a defect 150 , 350 , 550 can be repaired, it must first be identified and then analyzed. To analyze a defect 150 , 350 , 550 For example, an EUV-AIMS ™ (Aerial Image Measurement System) can be used. the 14th shows in the left part of the picture 1410 a plan view of a section of a strip structure 1420 who have a defect 1450 having. The right part of the picture 1415 the 14th presents a top view of a section of a defect-free reference strip structure 1425 . Both images were taken with an EUV-AIMS ™. The defect can be seen in the left partial image 1450 be analyzed in detail. Analysis of the defect 1450 can be a comparison of the defective stripe structure 1420 with the defect-free reference strip structure 1425 include. From the detailed analysis of the defect 1450 becomes a form of repair for the defect 1450 created. The form of repair determines, for example, the type of defect, the size of the defect, the position of the defect with respect to one or more pattern elements, the pattern type of the EUV mask, and the exposure setting of the scanner during operation of the mask. The one for the defect 1450 certain form of repair is attached to the device 700 to have the defect repaired.

the 15th schematically presents the repair of the defect 1450 the 14th by an embodiment of the device 700 . The upper left part of the picture 1510 the 15th essentially shows the detail of the left partial image of 14th like him from the EUV photon beam 750 , 830 , 1130 the device 700 is mapped in examination mode. The device 700 "Sees" the defect in examination or imaging mode 1450 the 14th . The upper left part of the picture 1515 shows the reference stripe structure 1525 the 14th except with the EUV photon beam 750 , 830 , 1130 the device 700 .

By the arrow 1580 is in the 15th the repair process of the defect 1450 by the EUV photon beam 630 , 840 , 1030 symbolizes the device. The device 700 receives, as already stated above, a form of repair for the defect from the defect review tool, for example an EUV-AIMS ™ 1450 . To repair the defect 1450 becomes the EUV photon beam 630 , 840 , 1030 , as specified by the form of repair, about the defect 150 , 350 , 550 , 1450 scanned.

The repair of the defect 1450 can be interrupted from time to time to analyze the remaining defect. The repair can be interrupted periodically or can be specified by the type of repair.

The lower left part of the picture 1550 the 15th shows the section of the stripe structure 1530 of the upper left partial image 1510 after completion of the defect repair. The repaired area is in the strip structure 1530 of the partial image 1550 by the reference number 1560 illustrated. The lower right part of the picture 1555 reproduces the reference stripe structure again 1525 of the upper right part of the picture 1515 .

the 16 shows the repaired section 1530 of the lower left part of the picture 1550 the 15th recorded with the EUV-AIMS ™. The repaired spot 1560 who have favourited the repaired position 1560 or the repaired area 1560 is in the partial picture 1610 marked. The right part of the picture is for comparison purposes 1615 the reference strip structure 1425 of the partial image 1415 again. The synopsis of 16 it can be seen that the device 700 the defect 1450 has repaired it to such an extent that it is no longer visible in an aerial photo of an EUV-AIMS ™.

the 17th gives a flow chart 1700 an overall sequence of a defect repair of an optical component 100 , 300 , 500 for the EUV wavelength range again. The procedure starts at block 1705 . In the first step 1710 becomes a picture of a defect 150 , 350 , 550 , 1450 or a defective position 150 , 350 , 550 , 1450 the optical EUV component 100 , 300 , 500 recorded. This step is typically carried out with a review tool such as an EUV-AIMS ™. Then at step 1715 a reference image of a defect-free reference position also recorded with a review tool. The step 1715 is an optional step. This is in the 17th symbolized by the dashed border.

At decision block 1720 is then determined based on the image of the defect 150 , 350 , 550 , 1450 possibly with the aid of a reference image, it determines whether the defect is to be repaired 150 , 350 , 550 , 1450 is necessary or not. If a repair is not necessary, the process jumps to block 1775 , in which it is decided whether the EUV mask 100,300,500 further defects 150 , 350 , 550 , 1450 having. If this is not the case, the method ends at block 1780 and the EUV optical component 100 , 300 , 500 is ready for use. If the optical EUV component 100 , 300 , 500 an EUV mask 100 , 300 , 500 it is ready for use in a scanner. If there are other defects 150 , 350 , 550 , 1450 on the EUV mask 100 , 300 , 500 are present, the process jumps to block 1710 , in which an image of the next defect 150,350,550,1450 is taken with an EUV-AIMS ™.

In case a repair of the defective position 150 , 350 , 550 , 1450 is necessary, the procedure advances to block 1725 continued with the device 700 or the repair device 700 a picture of the defective position 150 , 350 , 550 , 1450 or the defect 150 , 350 , 550 , 1450 is recorded in examination mode. Then at Block 1730 a form of repair for the defective item 150 , 350 , 550 , 1450 determined. The form of repair for the defect 150 , 350 , 550 , 1450 can step with that 1710 Image recorded with a review tool may be determined in combination with the reference image. Alternatively, the form of repair can be made from the device or devices 700 or repair device i700 m the examination mode recorded image or images are determined. Alternatively, it is also possible to repair the defect 150 , 350 , 550 , 1450 from the combined consideration of at step 1710 and 1725 measured images of the defective position 150 , 350 , 550 , 1450 to determine.

At decision block 1735 a decision is made as to whether to process or repair the defect 150 , 350 , 550 , 1450 to one of the local increase 1740 or a local acceptance 1755 the reflectivity of the EUV mask 100 , 300 , 500 should lead. If the defect 150 , 350 550 , 1450 a defect 150 , 550 excess material is when block 1750 with the photon beam 630 , 840 , 1030 Excess absorber material from one or more pattern elements 140 or the excess material of the particle 550 removed from the EUV mask 100,500 by ablation.

If the intended change in the defect repair is a local decrease in the reflected optical intensity, then at Block 1755 the multilayer structure 120 the EUV mask 300 with the photon beam 630 , 840 , 1030 machined to be part of the multilayer structure 120 the EUV mask 100 , 300 , 500 to remove or at least reduce the planarity.

Both machining processes 1750 and 1755 direct the proceedings to block 1765 further where a picture of the repaired item 150 , 350 , 550 , 1450 the EUV mask 100 , 300 , 500 with the examination mode of the device 700 is recorded. At decision block 1770 it is decided whether to repair the defect 150 , 350 , 550 , 1450 is completed. If this is not the case, the process jumps to block 1725 where with the repair device 700 an image of the remaining defect is recorded in the examination mode. If at decision block 1770 it is determined that the repair of the defect 150 , 350 , 550 , 1450 is complete, the process moves to decision block 1775 away. At decision block 1775 it is determined whether the EUV mask 100 , 300 , 500 further defects 150 , 350 , 550 , 1450 has. If this is the case, the process jumps to block 1710 and measures an image of the nearest defect. If there are no other defects 150 , 350 , 550 , 1450 are present on the mask 100,300,500, the method ends at block 1780 .

Finally, the flowchart shows 1800 the 18th essential steps of a method according to the invention for repairing at least one defect 150 , 350 , 550 , 1450 an optical component 100 , 300 , 500 for the extreme ultraviolet wavelength range that a substrate 110 and a multilayer structure 120 having. The procedure starts at step 1810 . In the first step 1820 becomes a photon beam 610 , 1010 , 1020 generated in the EUV wavelength range and / or in the wavelength range of soft X-rays. At block 1830 becomes the photon beam 610 , 1030 , 1130 set so that by locally changing the optical component 100 , 300 , 500 the at least one defect 150 , 350 , 550 , 1450 being repaired. Finally, the process ends at block 1840 .

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2016/037851 A1 [0005]
• WO 2011/161243 A1 [0005]
• WO 2013/010976 A1 [0005]
• WO 2015/144700 A1 [0005]

Non-patent literature cited

• L. Pang et al .: “Compensation of EUV multilayer defects within arbitrary layout by absorber pattern modification”, in “Extreme Ultraviolet Lithography”, edited by B.M. Fontaine and P.P. Naulleau, Proc. of SPIE Vol. 7969, 79691E-1 - 79691E-14 [0005]
• M. Waiblinger et al .: “The door opener for EUV mask repair”, in “Photomask and Next Generation Lithography Mask Technology XIV”, edited by K. Kato, Proc. of SPIE, Vol. 84441, 8,4,41oF-1 - 84410F-10 [0005]
• G. McIntyre et al .: “Through-focus EUV multilayer defect repair with micromachining”, in “Extreme Ultraviolet (EUV) Lithography IV, edited by P.P. Naulleau, Proc. of SPIE, Vol. 8679, 867911-1-867911-4 [0005]
• S. Hädrich et al .: "High photon flux tabletop coherent extreme ultraviolet source", DOI: 10.1038 / nphoton.2014.214, arXiv: 1403.4631 [0007]
• H. Carstens et al .: "High-harmonic generation at 250 MHz with photon energies exceeding 100 eV", Optica, Vol. 3, No. 4 / April 2016, pp. 366-369, Nature Photonics, Vol. 8, pp. 779-783 (2014) [0007]
• "Understanding thin film laser ablation: The role of the effective penetration depth and film thickness", Physics Procedia, Vol 56, pp. 1007-1014 (2014) [0008]
• M. Domke et al. the removal of a thin metal layer from an optically transparent material with the help of laser pulses. The authors J. Na et al. describe in the article "Application of actinic mask review system for the preparation of HVM EUV lithography with defect free mask", BACUS, Vol. 33, July 2017, pp. 1-8 [0008]
• K.H. Leitz et al. investigate in the article "Metal Ablation with Short and Ultrashort Laser Pulses", Physics Procedia 12 (011), pp. 230-238 [0069]

Claims (20)

Device (700) for repairing at least one defect (150, 350, 550, 1450) of an optical component (100, 300, 500) for the extreme ultraviolet (EUV) wavelength range, the optical component (100, 300, 500) being a substrate (110) and a multilayer structure (120) arranged on the substrate (110), comprising: a. at least one light source (610, 1010, 1020) which is designed to generate a photon beam (605, 1030, 1130) in the EUV wavelength range and / or in the wavelength range of soft X-rays; and b. wherein the at least one light source (605, 1030, 1130) is further designed to repair the at least one defect (150, 350, 550, 1450) by locally changing the optical component (100, 300, 500). Device (700) according to the preceding claim, wherein the local changing of the optical component (100, 300, 500) comprises a local change of a reflectivity of the optical component (100, 300, 500) in the range of an actinic wavelength. Device (700) according to one of the preceding claims, wherein the local changing of the optical component (100, 300, 500) is a local removal of material from the optical component (100, 300, 500) with the photon beam (630, 840, 1030) includes. The device (700) according to the preceding claim, wherein the local removal of material comprises at least one element from the group: removal of excess material of at least one element of an absorber pattern (140) of a photolithographic mask (100), removal of material from the multilayer structure ( 120) of the optical component (300), and removing at least one particle (550) from the optical component (500). Device (700) according to one of the preceding claims, wherein the at least one light source (610, 1010, 1020) is further designed to set an energy density of the photon beam (605, 1030, 1130) for repairing the at least one defect (150,350,550,1450) of the optical Component (100, 300, 500) to be set. Device (700) according to one of the preceding claims, further comprising a detector (780) for detecting photons reflected from the optical component (100,300,500), and / or an energy sensor (690) for detecting the optical component (100, 300, 500) and / or photons reflected from the at least one defect (150, 350, 550, 1450) during a repair for monitoring the repair. Device (700) according to the preceding claim, wherein the device (700) is designed to operate the at least one light source (610, 1010, 1020) and the energy sensor (690) in a closed feedback loop. Device (700) according to one of the preceding claims, further comprising at least one first mirror (620) for scanning the photon beam (630) over the at least one defect (150, 350, 550, 1450) of the optical component (100, 300, 500) and at least one second mirror (660) for directing the photon beam (750) onto a region of the optical component (100, 300, 500) which comprises the at least one defect (150, 350, 500, 1450). Device (700) according to one of the preceding claims, further comprising a control device (750) which is designed to move the at least one first mirror (620) and / or the at least one second mirror (660) over a macroscopic distance. Device (700) according to one of the preceding claims, wherein the device (700) comprises a Fresnel zone plate (850), and / or wherein the control device (750) is designed to convert the Fresnel zone plate (850) into the photon beam (830) out and out of the photon beam (830). Device (700) according to the preceding claim, wherein the control device (750) is further designed to configure the device (700) for an examination mode with the photon beam (750, 830, 1130), and / or wherein the control device (750) also is designed to switch the device (700) between the examination mode and a repair mode. Device (700) according to one of the preceding claims, further comprising a sample holder for fixing the optical component (100, 300, 500), which is designed to rotate the optical component (100, 300, 500) about at least one axis, and / or wherein the sample holder is further designed to displace the optical component (100, 300, 500) in at least one lateral direction in order to examine a substantially defect-free area of the optical component (100, 300, 500) with the photon beam (750, 830, 1130). Device (700) according to one of the preceding claims, wherein the at least one light source (610, 1010, 1020) comprises a first light source (1020) which is designed to be a focused one To scan the photon beam (1030) over the at least one defect (150, 350, 550, 1450) to repair the at least one defect (150,350,550,1450), and comprises a second light source (1020) which is designed to produce the photon beam (1130) to the area of the optical component (100, 300, 500) which comprises at least the at least one defect (150, 350, 550, 1450). Device (700) according to one of the preceding claims, wherein the optical component during the repair and / or during an examination comprises a pellicle (1310) through which the photon beam (630, 750, 830, 841030, 1130) penetrates. Method (1800) for repairing at least one defect (150, 350, 550, 1450) of an optical component (100, 300, 500) for the extreme ultraviolet (EUV) wavelength range, wherein the optical component (100, 300, 500) comprises a substrate (110 ) and a multilayer structure (120) arranged on the substrate (110), the method comprising the steps: a. Generating a photon beam (605, 1030, 1130) in the EUV wavelength range and / or in the wavelength range of soft X-ray radiation; and b. Adjusting the photon beam (605, 1030, 1130) so that the at least one defect (100, 300, 500) is repaired by locally changing the optical component (100, 300, 500). The method (1800) according to the preceding claim, wherein adjusting the photon beam (605, 1030, 1130) comprises at least one element from the group: focusing the photon beam (605, 1030, 1130), changing a pulse power of the photon beam (605, 1030, 1130), changing a polarization of the photon beam (605, 1030, 1130), and changing an angle of incidence of the photon beam (605, 1030, 1130) with respect to a normal direction of the optical component (100, 300, 500). Method (1800) according to Claim 15 or 16 , further comprising the step of: switching between repairing the at least one defect (150, 350, 550, 1450) of the optical component (100, 300, 500) with the photon beam (630, 840, 1030) and examining the optical component ( 100, 300, 500) and / or of the at least one defect (150, 350, 550, 1450) of the optical component (100, 300, 500) with the photon beam (750, 830, 1130). Method (1800) according to one of the Claims 15 - 17th , further comprising at least one of the steps: a. Examining the at least one defect (150,350,550,1450) with the photon beam (750, 830, 1130), and / or examining a substantially defect-free reference position with the photon beam (750, 830, 1130); b. Determining a form of repair for the at least one examined defect (150, 350, 550, 1450) if the at least one examined defect (150,350,550,1450) exceeds a predetermined threshold; c. Repairing the at least one defect (150,350,550,1450) with the photon beam (630, 840, 1030); d. Examining a repaired location of the optical component (100, 300, 500) with the photon beam (750, 830, 1130); and e. Repeat steps a. and b. if a remaining remainder of the at least one defect (150,350,550,1450) exceeds the predetermined threshold. Method (1800) according to one of the Claims 15 - 18th , wherein the device (700) according to one of Claims 1 until 14th is designed, the method steps of one of the Claims 15 until 18th to execute. Computer program which comprises instructions which, when executed by a computer system, cause the computer system to carry out the method steps of Claims 15 until 19th to execute.

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