DE102024200329A1 - Device and method for filtering a cooling lubricant, processing device and lithography system - Google Patents

Abstract

The invention relates to a device (1) for filtering a cooling lubricant (2), comprising a filter device (3) with a filter material (4). It is provided that the filter material (4) is designed for the targeted removal by binding at least one contamination (5) from the cooling lubricant (2) which has a tendency towards hydrogen-induced outgassing.

Description

The invention relates to a device for filtering a cooling lubricant, comprising a filter device with a filter material.

The invention further relates to a method for filtering a cooling lubricant by means of a filter device with a filter material.

The invention also relates to a processing device for the low-contamination production of a, preferably mechanical, component.

The invention also relates to a lithography system, in particular a projection exposure system for producing a semiconductor component, with a plurality of components, in particular an illumination system with a radiation source and an optics which has at least one optical element.

Strict cleanliness criteria are usually applied to mechanical components of lithography systems, especially EUV (extreme ultraviolet) projection exposure systems.

In order to achieve such strict cleanliness criteria, it is known from the state of the art to comply with strict cleanliness criteria of the material surfaces of the components already during the manufacture of the aforementioned mechanical components, in particular during the manufacture of EUV-compliant mechanical components.

In order to achieve the aforementioned cleanliness criteria, operating materials are used in accordance with the general state of the art which contain no or only a few contaminants.

From the EN 10 2005 021 057 A1 A process for processing cooling lubricants is known.

From the EP 2 283 908 B1 A device for the preparation of cooling lubricants is known.

Ion exchange cartridges for removing contamination for the purpose of producing ultrapure water are known from the state of the art. In particular, ion exchange cartridges for removing magnesium and its compounds and ions from a cooling lubricant are known. In addition, filter systems for solvents and cleaning systems for liquids are known from the general state of the art.

However, a disadvantage of the state-of-the-art strategies for contamination prevention is that, despite the use of the aforementioned contamination-free operating resources, a constant entry of various undesirable contaminants from unknown sources into an operating resource circuit of processing facilities or centers leads to irreversible contamination of the components to be manufactured.

Conventional filter units and/or ion exchange cartridges known from the state of the art, which could continuously filter out the disruptive contaminants, can under certain circumstances have a detrimental effect on the operating resources used.

The present invention is based on the object of creating a device for filtering a cooling lubricant, which avoids the disadvantages of the prior art, in particular enables the production of low-contamination components.

According to the invention, this object is achieved by a method having the features mentioned in claim 1.

The present invention is also based on the object of creating a method for filtering a cooling lubricant which avoids the disadvantages of the prior art, in particular enables the production of low-contamination components.

According to the invention, this object is achieved by a method having the features mentioned in claim 8.

The present invention is also based on the object of creating a processing device for the low-contamination production of a, preferably mechanical, component, which avoids the disadvantages of the prior art, in particular enables the production of low-contamination components.

According to the invention, this object is achieved by a processing device having the features mentioned in claim 12.

The present invention is also based on the object of creating a lithography system which avoids the disadvantages of the prior art, in particular enables uninterrupted operation over long periods of time.

According to the invention, this object is achieved by a lithography system having the features mentioned in claim 13.

The device according to the invention for filtering a cooling lubricant comprises a filter device with a filter material. According to the invention, the filter material is designed for the targeted removal by targeted binding of at least one contamination from the cooling lubricant which has a tendency towards hydrogen-induced outgassing.

In particular, it can be provided that the filter material is designed for targeted removal by targeted binding of at least almost exclusively the at least one contaminant from the cooling lubricant. Removal of other components of the cooling lubricant should preferably be avoided.

In order to achieve the strict cleanliness criteria that apply in particular to components for EUV projection exposure systems, the device according to the invention makes it possible to avoid so-called HiO contaminations.

HiO contaminations tend to result in hydrogen-induced outgassing (HiO for short).

HiO contamination is converted into a gas phase under conditions such as those that prevail in EUV projection exposure systems, for example by free hydrogen radicals, hydrogen ions, plasma conditions and conditions with reduced pressure, in particular ultra-high vacuum conditions, and can thus contribute to a deterioration in system performance. In particular, harmful deposits can be formed on the components of EUV projection exposure systems, which can reduce the service life of the system.

The inventors have recognized that despite the use of HiO-free operating fluids, a constant entry of various undesirable HiO contaminations from unknown sources into the cooling lubricant can occur.

The device according to the invention can prevent critical HiO contaminations in an EUV process chain and thus irreversible contaminations on components.

This can advantageously improve the service life of an overall photolithographic system.

In particular, the device according to the invention can be used to design the entire production of mechanical components for use in lithography systems with low contamination.

The cooling lubricant can in particular be a cooling lubricant of a processing device for producing a component, in particular a mechanical component.

In an advantageous development of the device according to the invention, it can be provided that the filter material consists of and/or is formed entirely or partially from at least one metal, in particular a high-purity metal, and/or at least one alloy of metals, in particular high-purity metals, and/or at least one metal compound and/or a metal-non-metal compound.

If at least one metal and/or a metal alloy, in particular in pure form, is used as filter material, the HiO contaminations show an advantageous specific affinity for binding to the filter material.

In particular, the targeted binding of the contamination to the filter material can be caused by chemisorption and/or physisorption.

Thus, the use of the aforementioned filter materials enables an advantageous specific or targeted removal of contamination from the cooling lubricant without negatively affecting the cooling lubricant used.

In particular, this can prevent a lubricant from being removed from a water-based cooling lubricant during filtration. Such removal of the lubricant can lead to a disadvantageous loss of the lubricating effect of the cooling lubricant in filter strategies known from the prior art.

In an advantageous development of the device according to the invention, it can be provided that the filter material is designed as a powder, as a granulate and/or as a film.

The use of powdered and/or granular and/or film-like filter materials is particularly advantageous.

The above-mentioned forms of filter material can be used to increase the specific surface area of the filter material. This results in a large interaction area between the filter material and the cooling lubricant and thus also a large area to which the contaminants can specifically bind.

Alternatively or in addition to the aforementioned forms of the filter material as powder, granulate and/or film, the filter material in the form of chips, sheets and/or wires. In general, filter material can advantageously be formed with a large surface-to-volume ratio.

In an advantageous development of the device according to the invention, it can be provided that the filter material consists entirely or partially of at least one transition metal and/or at least one metal-non-metal compound and/or comprises a powder, granulate and/or film coated with at least one transition metal and/or at least one metal-non-metal compound.

The inventors have recognized that transition metals and/or particles or powders, granules and/or films coated with transition metals and/or metal-non-metal compounds can also be used as filter material or filter media for operating fluids, in particular cooling lubricants.

In particular, the inventors have recognized that metals and/or compounds can be used as filter material or filter media for operating materials, in particular cooling lubricants, which are suitable for "capturing" HiO contamination, i.e., have a so-called "getter effect" and at the same time are not or cannot be a source of HiO contamination themselves.

Nickel can be used as the transition metal. Alternatively or additionally, iron and/or cobalt can also be used as the transition metal.

Nickel phosphate (NiP) can be used as a metal-non-metal compound.

In particular, mixtures of metals and transition metals can also be used as filter material. For example, an aluminum-nickel alloy can be used as filter material.

The chemical elements with atomic numbers 21 to 30, 39 to 48, 57 to 80 and 89 to 112 are referred to as transition metals in the context of the invention.

For the purposes of the invention, metals are defined as all chemical elements located in the periodic table of elements to the left and below a dividing line from boron to polonium.

Thus, within the scope of the invention, transition metals are also considered metals. However, not every metal is a transition metal. In particular, aluminum is not a transition metal.

In particular, it can be provided that the filter material consists entirely or partially of the transition metal nickel.

For example, the filter material may comprise an aluminium foil and a nickel foil.

It can be provided that a powder, granulate or film coated with metals, in particular ultra-pure metals, is used wholly or partially as filter material.

Coating a powder, granulate or film with a transition metal and/or a metal, in particular a high-purity metal, and/or their alloys results in a larger selection of starting materials for producing the powder, granulate and/or the film. For example, mineral powders, granulates or films, in particular made of ceramic, can be coated with metals, metal alloys, high-purity metals, high-purity metal alloys, metal compounds and/or transition metals or transition metal alloys and/or metal-nonmetal compounds.

It can further be provided that the filter material, in particular in the case of transition metals and/or transition metal compounds and/or transition metal alloys and/or metal-non-metal compounds, is in the form of powder, granules or foils.

It can be provided that the filter material comprises and/or consists of metal-coated particles, metal-coated granules and/or metal-coated films.

In an advantageous development of the device according to the invention, it can be provided that the filter material consists entirely or partially of aluminum and/or one or more types of aluminum compounds, in particular an aluminum oxide.

The inventors have recognized that aluminum, aluminum alloys and/or aluminum oxide, especially in powder form, in granulate form and/or in film form, represent another suitable filter medium or filter material. By using aluminum or aluminum oxide, the cooling lubricant, but also other operating materials, can be continuously freed from critical contamination.

The inventors have recognized that, for example, silicates, which are among the HiO contaminations, react with aluminum and/or aluminum compounds and passivate a surface of the filter material.

In an advantageous development of the device according to the invention, it can be provided that the contamination comprises fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead.

Fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead are considered to be particularly important components of HiO contamination. The aforementioned elements can be present as pure substances or elemental, as ions and/or as compounds with other elements or with each other.

The feature that the contamination contains fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead is to be understood within the scope of the invention in such a way that the contamination to be removed can contain individual, several or all of the following elements in the form of ions, as part of compounds and/or in elemental form: fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead.

The aforementioned elements or HiO elements can be contained in the HiO contamination to be extracted in the form of ions, as part of compounds and/or in elemental form.

It is therefore particularly advantageous if, in particular but not exclusively, the aforementioned HiO elements are removed from the cooling lubricant.

In this way, the aforementioned HiO elements can be avoided as contamination on the components to be manufactured.

It has been shown that the aforementioned filter materials in their aforementioned forms are particularly suitable for the specific or targeted binding and thus for the targeted removal of the aforementioned HiO elements.

In an advantageous development of the device according to the invention, it can be provided that the filter device has a container and/or a cartridge in which the filter material is arranged, and/or that a packing material is present for fixing the filter material.

It can be provided that the aforementioned filter materials are introduced into a cooling lubricant circuit in a container and/or a cartridge. In particular, this cooling lubricant circuit can be part of a processing device for processing a component for a lithography system.

It can also be provided that the filter material is introduced directly into a cooling lubricant supply of the processing device even without a container.

The presence of a packing material or packing medium for fixing the filter material has the advantage that the passage of the cooling lubricant through the filter material and/or along the filter material can be controlled particularly precisely.

Cellulose and/or nanofibers, in particular carbon nanofibers, can be used as packing material.

Especially when using containers and/or cartridges, filtration can be carried out in the form of dead-end filtration.

The invention further relates to a method for filtering a cooling lubricant with the features mentioned in claim 8.

In the method according to the invention for filtering a cooling lubricant by means of a filter device with a filter material, at least one contamination which has a tendency towards hydrogen-induced outgassing is specifically removed from the cooling lubricant by binding to the filter material.

The method according to the invention can prevent HiO contamination on components, in particular mechanical components in EUV projection exposure systems.

By means of the method according to the invention, these contaminations can be prevented or minimized already in the preliminary processes, in particular during mechanical processing of the components to be manufactured.

By means of the method according to the invention, an advantageous depletion of HiO contamination in the cooling lubricant can be achieved.

It can be provided that the filter material is made of an aluminum and/or an aluminum oxide in various embodiments, in particular a powder, granulate or a film.

In an advantageous development of the method according to the invention, it can be provided that the filter material in a container and/or a cartridge is introduced into a circuit of the cooling lubricant of a processing device in such a way that at least a part of a volume of the cooling lubricant flows continuously through the filter material, preferably an entire volume of the cooling lubricant flows continuously through the filter material.

If it is intended that the filter material is introduced into a cooling lubricant circuit in a container and/or a cartridge, it is advantageous if an entire cooling lubricant supply and/or a part of the cooling lubricant supply runs continuously through the filter material.

This allows the cooling lubricant to be continuously freed from critical HiO contamination, especially critical HiO elements. Particularly critical HiO contamination can contain one, several or all of the following elements in the form of ions, as part of compounds and/or in elemental form: fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead.

The aforementioned elements or HiO elements can be contained in the HiO contamination to be removed in the form of ions, as part of compounds and/or in elemental form. Such HiO contaminations are particularly critical.

The prescribed measures ensure that contamination is continuously removed from the coolant circuit. This can reduce the risk of contamination for the components being manufactured, especially for EUV components.

In an advantageous development of the method according to the invention, it can be provided that the filter material is introduced directly into a cooling lubricant supply, in particular a machine bed, of a processing device.

If the filter material is introduced directly into the coolant supply without a separate container, the filtration can preferably be carried out in the form of tangential flow filtration.

In an advantageous development of the method according to the invention, it can be provided that the cooling lubricant is filtered during production of a component, in particular an optical element, of a lithography system.

The component can in particular be a mechanical component of a lithography system that holds an optical element. For example, it can be a holder, frame and/or actuator.

However, the component can also be a mechanical component that generally contributes to the function of the entire lithography system.

In general, the component can be a mechanical component that is essential for the function of a lithography system.

The optical element can be designed in particular as a lens and/or as a mirror. However, the optical element can also comprise associated and/or mechanically connected parts.

The method according to the invention is particularly suitable for use in the production of an optical element of a lithography system.

Especially when the component to be manufactured, in particular an optical element, is used under the special conditions in EUV projection exposure systems, production under low-HiO contamination conditions according to the method according to the invention is particularly advantageous.

Contaminations that are prone to hydrogen-induced outgassing exhibit these outgassings particularly under the conditions in EUV projection exposure systems, which have a high occurrence of radicals, especially free hydrogen radicals, ions, especially hydrogen ions, as well as high vacuum conditions.

The invention further relates to a processing device having the features mentioned in claim 12.

The processing device according to the invention serves for the low-contamination production of a preferably mechanical component. In particular, the processing device according to the invention serves for the low-contamination production of a component of a lithography system. A device according to the invention is provided in the processing device. Alternatively or additionally, the processing device according to the invention is set up to carry out a method according to the invention.

The processing device according to the invention has, through the use of the inventive The device and/or the execution of the method according to the invention have the advantage that they can be used to produce components for lithography systems that are particularly low in contamination, in particular particularly low in HiO contamination. As a result, the components can be used particularly advantageously in the conditions that prevail in lithography systems.

The invention further relates to a lithography system having the features mentioned in claim 13.

The lithography system according to the invention, which can in particular be a projection exposure system for producing a semiconductor component, comprises a plurality of components. In particular, the lithography system according to the invention comprises an illumination system with a radiation source and an optics which has at least one optical element. According to the invention, it is provided that at least one of the components, in particular at least one of the optical elements, is partially or completely produced using a device according to the invention and/or using a method according to the invention.

The lithography system according to the invention has an advantageously long service life, since the components installed in the lithography system according to the invention do not have any contamination that would tend to hydrogen-induced outgassing. This makes it possible to avoid harmful hydrogen-induced outgassing, which has a negative impact on the service life of the overall photolithographic system.

The hydrogen radicals and ions that are particularly prevalent in EUV projection exposure systems also break down inorganic compounds, so that silicon oxide, for example, can be converted into silanes. These can in turn pass into a gas phase.

Features that have been described in connection with one of the objects of the invention, namely given by the device according to the invention, the method according to the invention, the processing device according to the invention or the EUV projection exposure system according to the invention, can also be advantageously implemented for the other objects of the invention. Likewise, advantages that have been mentioned in connection with one of the objects of the invention can also be understood to relate to the other objects of the invention.

It should also be noted that terms such as "comprising", "having" or "with" do not exclude other features or steps. Furthermore, terms such as "a" or "the", which refer to a singular number of steps or features, do not exclude a plurality of features or steps - and vice versa.

In a purist embodiment of the invention, however, it can also be provided that the features introduced in the invention with the terms "comprising", "having" or "with" are listed exhaustively. Accordingly, one or more lists of features can be considered complete within the scope of the invention, for example considered for each claim. The invention can, for example, consist exclusively of the features mentioned in claim 1.

It should be noted that terms such as “first” or “second” etc. are used primarily for reasons of distinguishing between respective device or process features and are not necessarily intended to indicate that features are mutually dependent or related to one another.

In the following, embodiments of the invention are described in more detail with reference to the drawing.

The figures each show preferred embodiments in which individual features of the present invention are shown in combination with one another. Features of one embodiment can also be implemented separately from the other features of the same embodiment and can therefore be easily combined by a person skilled in the art to form further useful combinations and sub-combinations with features of other embodiments.

In the figures, functionally identical elements are provided with the same reference symbols.

• 1 eine EUV-Projektionsbelichtungsanlage im Meridionalschnitt;
• 2 eine DUV-Projektionsbelichtungsanlage;
• 3 eine schematische Darstellung einer möglichen Ausführungsform einer erfindungsgemäßen Vorrichtung;
• 4 eine schematische Darstellung einer weiteren möglichen Ausführungsform der erfindungsgemäßen Vorrichtung;
• 5 eine schematische Darstellung einer weiteren möglichen Ausführungsform der erfindungsgemäßen Vorrichtung;
• 6 eine blockdiagrammartige Darstellung einer möglichen Ausführungsform eines erfindungsgemäßen Verfahrens;
• 7 eine schematische Darstellung einer möglichen Ausführungsform einer erfindungsgemäßen Bearbeitungseinrichtung; und
• 8 eine schematische Darstellung einer weiteren möglichen Ausführungsform einer erfindungsgemäßen Bearbeitungseinrichtung.

Show it:

• 1 an EUV projection exposure system in meridional section;
• 2 a DUV projection exposure system;
• 3 a schematic representation of a possible embodiment of a device according to the invention;
• 4 a schematic representation of another possible embodiment of the device according to the invention;
• 5 a schematic representation of another possible embodiment of the device according to the invention;
• 6 a block diagram representation of a possible embodiment of a method according to the invention;
• 7 a schematic representation of a possible embodiment of a processing device according to the invention; and
• 8th a schematic representation of another possible embodiment of a processing device according to the invention.

In the following, with reference to 1 The essential components of an EUV projection exposure system 100 for microlithography are described as an example of a lithography system. The description of the basic structure of the EUV projection exposure system 100 and its components should not be understood as limiting.

An illumination system 101 of the EUV projection exposure system 100 has, in addition to a radiation source 102, illumination optics 103 for illuminating an object field 104 in an object plane 105. A reticle 106 arranged in the object field 104 is exposed. The reticle 106 is held by a reticle holder 107. The reticle holder 107 can be displaced via a reticle displacement drive 108, in particular in a scanning direction.

In 1 For explanation purposes, a Cartesian xyz coordinate system is shown. The x-direction runs perpendicular to the drawing plane. The y-direction runs horizontally and the z-direction runs vertically. The scanning direction runs in 1 along the y-direction. The z-direction is perpendicular to the object plane 105.

The EUV projection exposure system 100 comprises a projection optics 109. The projection optics 109 are used to image the object field 104 into an image field 110 in an image plane 111. The image plane 111 runs parallel to the object plane 105.

Alternatively, an angle other than 0° between the object plane 105 and the image plane 111 is also possible.

A structure on the reticle 106 is imaged onto a light-sensitive layer of a wafer 112 arranged in the area of the image field 110 in the image plane 111. The wafer 112 is held by a wafer holder 113. The wafer holder 113 can be displaced via a wafer displacement drive 114, in particular along the y-direction. The displacement of the reticle 106 via the reticle displacement drive 108 on the one hand and the wafer 112 via the wafer displacement drive 114 on the other hand can be synchronized with one another.

The radiation source 102 is an EUV radiation source. The radiation source 102 emits in particular EUV radiation 115, which is also referred to below as useful radiation or illumination radiation. The useful radiation 115 has in particular a wavelength in the range between 5 nm and 30 nm. The radiation source 102 can be a plasma source, for example an LPP source (“laser produced plasma”, plasma generated using a laser) or a DPP source (“gas discharged produced plasma”, plasma generated by means of gas discharge). It can also be a synchrotron-based radiation source. The radiation source 102 can be a free-electron laser (FEL).

The illumination radiation 115 that emanates from the radiation source 102 is bundled by a collector 116. The collector 116 can be a collector with one or more ellipsoidal and/or hyperboloidal reflection surfaces. The at least one reflection surface of the collector 116 can be exposed to the illumination radiation 115 in grazing incidence (GI), i.e. with angles of incidence greater than 45°, or in normal incidence (NI), i.e. with angles of incidence less than 45°. The collector 116 can be structured and/or coated on the one hand to optimize its reflectivity for the useful radiation 115 and on the other hand to suppress stray light.

After the collector 116, the illumination radiation 115 propagates through an intermediate focus in an intermediate focal plane 117. The intermediate focal plane 117 can represent a separation between a radiation source module, comprising the radiation source 102 and the collector 116, and the illumination optics 103.

The illumination optics 103 comprise a deflection mirror 118 and a first facet mirror 119 arranged downstream of this in the beam path. The deflection mirror 118 can be a flat deflection mirror or alternatively a mirror with a beam-influencing effect beyond the pure deflection effect. Alternatively or additionally, the deflection mirror 118 can be designed as a spectral filter that separates a useful light wavelength of the illumination radiation 115 from stray light of a different wavelength. If the first facet mirror 119 is arranged in a plane of the illumination optics 103 that is optically conjugated to the object plane 105 as a field plane, it is also referred to as a field facet mirror. The first facet mirror 119 comprises a plurality of individual first facets 120, which are also referred to below as field facets. Of these facets 120, 1 only a few examples are shown.

The first facets 120 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or partially circular edge contour. The first facets 120 can be designed as flat facets or alternatively as convex or concave curved facets.

As for example from the EN 10 2008 009 600 A1 As is known, the first facets 120 themselves can also be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 119 can in particular be designed as a microelectromechanical system (MEMS system). For details, please refer to the EN 10 2008 009 600 A1 referred to.

Between the collector 116 and the deflection mirror 118, the illumination radiation 115 runs horizontally, i.e. along the y-direction.

In the beam path of the illumination optics 103, a second facet mirror 121 is arranged downstream of the first facet mirror 119. If the second facet mirror 121 is arranged in a pupil plane of the illumination optics 103, it is also referred to as a pupil facet mirror. The second facet mirror 121 can also be arranged at a distance from a pupil plane of the illumination optics 103. In this case, the combination of the first facet mirror 119 and the second facet mirror 121 is also referred to as a specular reflector. Specular reflectors are known from the US 2006/0132747 A1 , the EP 1 614 008 B1 and the US$6,573,978 .

The second facet mirror 121 comprises a plurality of second facets 122. In the case of a pupil facet mirror, the second facets 122 are also referred to as pupil facets.

The second facets 122 can also be macroscopic facets, which can be round, rectangular or hexagonal, for example, or alternatively facets composed of micromirrors. In this regard, reference is also made to the EN 10 2008 009 600 A1 referred to.

The second facets 122 may have planar or alternatively convex or concave curved reflection surfaces.

The illumination optics 103 thus forms a double-faceted system. This basic principle is also called the fly's eye integrator.

It may be advantageous not to arrange the second facet mirror 121 exactly in a plane which is optically conjugated to a pupil plane of the projection optics 109.

With the help of the second facet mirror 121, the individual first facets 120 are imaged into the object field 104. The second facet mirror 121 is the last bundle-forming or actually the last mirror for the illumination radiation 115 in the beam path in front of the object field 104.

In a further embodiment of the illumination optics 103 (not shown), a transmission optics can be arranged in the beam path between the second facet mirror 121 and the object field 104, which contributes in particular to the imaging of the first facets 120 in the object field 104. The transmission optics can have exactly one mirror, but alternatively also two or more mirrors, which are arranged one behind the other in the beam path of the illumination optics 103. The transmission optics can in particular comprise one or two mirrors for perpendicular incidence (NI mirrors, “normal incidence” mirrors) and/or one or two mirrors for grazing incidence (GL mirrors, “grazing incidence” mirrors).

The illumination optics 103 has in the design shown in the 1 As shown, after the collector 116 there are exactly three mirrors, namely the deflection mirror 118, the field facet mirror 119 and the pupil facet mirror 121.

In a further embodiment of the illumination optics 103, the deflection mirror 118 can also be omitted, so that the illumination optics 103 can then have exactly two mirrors after the collector 116, namely the first facet mirror 119 and the second facet mirror 121.

The imaging of the first facets 120 by means of the second facets 122 or with the second facets 122 and a transmission optics into the object plane 105 is usually only an approximate imaging.

The projection optics 109 comprises a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the EUV projection exposure system 100.

In the 1 In the example shown, the projection optics 109 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve or another number of mirrors Mi are also possible. The penultimate mirror M5 and the last mirror M6 each have a passage opening for the illumination radiation 115. The projection optics 109 are doubly obscured optics. The projection optics 109 have a numerical aperture on the image side that is greater than 0.5 and can also be greater than 0.6 and can be, for example, 0.7 or 0.75.

Reflection surfaces of the mirrors Mi can be designed as free-form surfaces without a rotational symmetry axis. Alternatively, the reflection surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one rotational symmetry axis of the reflection surface shape. The mirrors Mi, just like the mirrors of the illumination optics 103, can have highly reflective coatings for the illumination radiation 115. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

The projection optics 109 have a large object-image offset in the y-direction between a y-coordinate of a center of the object field 104 and a y-coordinate of the center of the image field 110. This object-image offset in the y-direction can be approximately as large as a z-distance between the object plane 105 and the image plane 111.

The number of intermediate image planes in the x and y directions in the beam path between the object field 104 and the image field 110 can be the same or can be different depending on the design of the projection optics 109. Examples of projection optics with different numbers of such intermediate images in the x and y directions are known from US 2018/0074303 A1 .

Each of the pupil facets 122 is assigned to exactly one of the field facets 120 to form an illumination channel for illuminating the object field 104. This can result in particular in illumination according to the Köhler principle. The far field is broken down into a plurality of object fields 104 using the field facets 120. The field facets 120 generate a plurality of images of the intermediate focus on the pupil facets 122 assigned to them.

The field facets 120 are each imaged onto the reticle 106 by an associated pupil facet 122, superimposing one another, to illuminate the object field 104. The illumination of the object field 104 is in particular as homogeneous as possible. It preferably has a uniformity error of less than 2%. The field uniformity can be achieved by superimposing different illumination channels.

By arranging the pupil facets, the illumination of the entrance pupil of the projection optics 109 can be defined geometrically. By selecting the illumination channels, in particular the subset of the pupil facets that guide light, the intensity distribution in the entrance pupil of the projection optics 109 can be set. This intensity distribution is also referred to as the illumination setting.

A likewise preferred pupil uniformity in the area of defined illuminated sections of an illumination pupil of the illumination optics 103 can be achieved by a redistribution of the illumination channels.

In the following, further aspects and details of the illumination of the object field 104 and in particular the entrance pupil of the projection optics 109 are described.

The projection optics 109 can in particular have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

The entrance pupil of the projection optics 109 cannot usually be illuminated precisely with the pupil facet mirror 121. When the projection optics 109 images the center of the pupil facet mirror 121 telecentrically onto the wafer 112, the aperture rays often do not intersect at a single point. However, a surface can be found in which the pairwise determined distance of the aperture rays is minimal. This surface represents the entrance pupil or a surface conjugated to it in spatial space. In particular, this surface shows a finite curvature.

It is possible that the projection optics 109 have different positions of the entrance pupil for the tangential and the sagittal beam path. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second facet mirror 121 and the reticle 106. With the help of this optical component, the different positions of the tangential entrance pupil and the sagittal entrance pupil can be taken into account.

In the 1 In the arrangement of the components of the illumination optics 103 shown, the pupil facet mirror 121 is arranged in a surface conjugated to the entrance pupil of the projection optics 109. The first field facet mirror 119 is tilted to the object plane 105. The first facet mirror 119 is tilted to an arrangement plane that is defined by the deflection mirror 118.

The first facet mirror 119 is arranged tilted to an arrangement plane which is defined by the second facet mirror 121.

In 2 an exemplary DUV projection exposure system 200 is shown. The DUV projection exposure system 200 has an illumination system 201, a device called a reticle stage 202 for receiving and precisely positioning a reticle 203, by means of which the later structures on a wafer 204 are determined, a wafer holder 205 for holding, moving and precisely positioning the wafer 204 and an imaging device, namely a projection optics 206, with several optical elements, in particular lenses 207, which are held via mounts 208 in an objective housing 209 of the projection optics 206.

Alternatively or in addition to the lenses 207 shown, various refractive, diffractive and/or reflective optical elements, including mirrors, prisms, end plates and the like, can be provided.

The basic functional principle of the DUV projection exposure system 200 provides that the structures introduced into the reticle 203 are imaged onto the wafer 204.

The illumination system 201 provides a projection beam 210 in the form of electromagnetic radiation required for imaging the reticle 203 onto the wafer 204. A laser, a plasma source or the like can be used as a source for this radiation. The radiation is shaped in the illumination system 201 via optical elements such that the projection beam 210 has the desired properties with regard to diameter, polarization, shape of the wave front and the like when it strikes the reticle 203.

An image of the reticle 203 is generated by means of the projection beam 210 and is transferred to the wafer 204 in a reduced size by the projection optics 206. The reticle 203 and the wafer 204 can be moved synchronously so that areas of the reticle 203 are imaged onto corresponding areas of the wafer 204 practically continuously during a so-called scanning process.

Optionally, an air gap between the last lens 207 and the wafer 204 can be replaced by a liquid medium having a refractive index greater than 1.0. The liquid medium can be, for example, high-purity water. Such a structure is also referred to as immersion lithography and has an increased photolithographic resolution.

The use of the invention is not limited to use in projection exposure systems 100, 200, in particular not with the described structure. The invention is suitable for any lithography systems or microlithography systems, but in particular for projection exposure systems with the described structure. The invention is also suitable for EUV projection exposure systems which have a smaller image-side numerical aperture than that which is used in connection with 1 described, and do not have an obscured mirror M5 and/or M6. In particular, the invention is also suitable for EUV projection exposure systems which have an image-side numerical aperture of 0.25 to 0.6, preferably 0.3 to 0.4, particularly preferably 0.33. The invention and the following embodiments are also not to be understood as being limited to a specific design.

The following figures represent the invention merely by way of example and in a highly schematic manner.

3 shows a schematic representation of a possible embodiment of a device 1 for filtering a cooling lubricant 2. The device 1 has a filter device 3 with a filter material 4. The filter material 4 is designed for the targeted binding and thus for the targeted removal of at least one contamination 5 from the cooling lubricant 2. The contamination 5 has a tendency towards hydrogen-induced outgassing.

In the 3 In the illustrated embodiment of the device 1, the filter device 3 has a container 6 in which the filter material 4 is arranged.

Furthermore, in the 3 In the illustrated embodiment of the device 1, a packing material 7 is present for fixing the filter material 2.

In the 3 In the embodiment shown and in all other embodiments, it can be provided that the filter material 4 consists of and/or is formed entirely or partially from at least one metal, in particular a high-purity metal, and/or at least one alloy of metals, in particular high-purity metals, and/or at least one metal compound and/or at least one metal-non-metal compound.

Alternatively or additionally, the filter material 4 can also be made entirely or partially from a coated material.

Preferably, the filter material 2 consists entirely or partially of aluminum and/or one or more types of aluminum compounds, in particular an aluminum oxide.

In the 3 In the embodiment shown, the packaging material 7 or the packaging medium is preferably partially or entirely made of cellulose and/or nanofibers.

A possible inlet and an outlet of the cooling lubricant into the container 6 or a coolant flow through the container 6 is in 3 symbolized by arrows.

4 shows a schematic representation of another possible embodiment of the device.

In the 4 In the illustrated embodiment of the device 1, the filter device 3 has a cartridge 8. The cooling lubricant 2 is introduced into the filter device 3 via an inlet channel 9 and forced to pass through the filter material 4.

With the 4 The structure of the device 1 shown may include an inlet, 4 provided by the inlet channel 9 and an outlet for the cooling lubricant 2 are located on the same side of the filter device 3. For this purpose, reference is made to the arrow representations in 4 referred to.

5 shows a schematic representation of another possible embodiment of the device 1.

It can preferably be provided that the filter material 4 has a plurality of different filter media 4a, 4b.

In the 5 In the embodiment shown, the filter material 4 has exactly two filter media 4a and 4b.

The configuration of the 5 The embodiment of the device 1 shown otherwise corresponds to that in 3 illustrated embodiment of the device 1.

In the 5 In the embodiment shown, a first filter medium 4a is shown with vertical dashed lines, while a second filter medium 4b is shown with diagonal lines.

It can be provided that the filter media 4a, 4b are made of different materials. In this case, the filter media 4a, 4b can be selected in particular from the materials described for the formation of the filter material 4, in particular the metals and/or metal alloys and/or metal compounds.

For example, it can be provided that the first filter medium 4a comprises and/or consists of an aluminum and/or one or more types of aluminum compounds, in particular an aluminum oxide.

For example, it can be provided that the second filter medium 4b consists entirely or partially of at least one transition metal and/or at least one metal-non-metal compound.

In other words, the filter material 4 in the embodiments shown in the figures can contain different types and classes of materials or can also be made of only one material.

In the in the 3 to 5 In the embodiments shown, the filter material 4 is preferably designed as a powder, granulate and/or as a film.

However, for the sake of simplicity, the filter material 4 is shown in the figures in line form.

In particular, the 3 to 5 In the embodiments shown, the filter material 4 can also consist entirely or partially of at least one transition metal and/or at least one metal-non-metal compound.

Alternatively or additionally, the filter material 4 may comprise a powder, granulate or film coated with at least one transition metal and/or at least one metal-non-metal compound.

Likewise, in the embodiments shown in the figures, it can preferably be provided that the filter material 4 comprises at least one metal, in particular a high-purity metal, and/or at least one alloy of metals, in particular high-purity metals, and/or at least one metal compound and/or consists exclusively of these.

In the 3 to 5 illustrated embodiments of the device 1 as well as in the 7 and 8th In the embodiments explained later, the at least one contamination 5 comprises fluorine, chlorine, sulphur, phosphorus, silicon zium, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead. The presence of the aforementioned elements is 7 and 8th by the corresponding element abbreviations of the elements calcium, silicon, phosphorus, fluorine, chlorine and/or zinc in 7 exemplifies. The 7 However, it is to be understood that all of the above-mentioned elements are represented by the element abbreviations of calcium, silicon, phosphorus, fluorine, chlorine and/or zinc. This also applies analogously to the 8th .

In the 5 An inlet direction and an outlet direction of the filter device 3 are symbolized by arrows.

6 shows a block diagram of a possible embodiment of a method for filtering the cooling lubricant 2.

In a feed block 30, the cooling lubricant 2 is fed to the filter device 3.

In a filter block 31, the at least one contamination 5, which has a tendency towards hydrogen-induced outgassing, is specifically removed from the cooling lubricant 2 by binding to the filter material 4. In a return block 32, the filtered cooling lubricant 2 is removed from the filter device 3.

The filter material 4 is preferably introduced in the container 6 or the cartridge 8 into a circuit of the cooling lubricant 2 of a processing device 10 (see 7 ) such that at least a portion of a volume of the cooling lubricant 2 flows continuously through the filter material 4. Particularly preferably, an entire volume of the cooling lubricant 2 flows continuously through the filter material 4.

Alternatively or additionally, within the framework of the 7 The filter material 4 is preferably introduced directly into a cooling lubricant supply 11, in particular a machine bed 12 (see 8th ) of the processing device 10.

Preferably, the cooling lubricant 2 is 7 shown process during the manufacture of a component 13 (see 7 ), in particular a mechanical component and/or an optical element 116, 118, 119, 120, 121, 122, Mi, 207 of a lithography system.

7 shows a schematic representation of a possible embodiment of a processing device 10 for the low-contamination production of the, preferably mechanical, component 13, in particular a component 13 of a lithography system. In this case, the processing device 10 comprises the device 1, as shown in the 3 , 4 and 5 Alternatively or additionally, the processing device 10 is designed to carry out the process described in connection with 6 described procedure.

With regard to the reference numerals relating to the device 1, reference is made to 3 , 4 and 5 referred to.

In the 7 In the embodiment shown, a pre-filter device 14 is preferably provided for pre-filtration of particles from the cooling lubricant 2.

In the 7 In the embodiment shown, a circuit of the cooling lubricant 2 in the processing device 10 is visible.

The processing device 10 has a pump device 15 to circulate the cooling lubricant 2.

The cooling lubricant 2 is supplied to a machining center 16 of the machining device 10 by the pump device 15.

At this point, the cooling lubricant 2 is uncontaminated or has reduced contamination, which in 7 symbolized by empty, closely dashed ovals.

During the processing of the component 13, in particular during machining of the component 13, contaminants 5 accumulate in the cooling lubricant 2. The contaminants 5 can also originate from the processing device 10 itself; in particular, galvanized machine components and/or brass can represent sources of contamination.

It can preferably be provided that the processing device 10 has a milling machine.

In 7 the enriched contaminants 5 are shown as broadly dashed ovals.

During the processing, the contamination may include 5 fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead. This is indicated by the corresponding element abbreviations of the elements calcium, silicon, phosphorus, fluorine, chlorine and/or zinc in 7 exemplifies. The 7 is to be understood that all of the above elements are replaced by the element abbreviations of the elements calcium, silicon, phosphorus, fluorine, chlorine and/or zinc. This also applies analogously to the 8th .

The processing process runs in the 7 example shown in a machine room 17, which is supplied with the cooling lubricant 2 by the cooling lubricant supply 11.

The contaminated cooling lubricant 2 leaves the machine room 17 and is fed to the pre-filter device 14. In the pre-filter device 14, contamination 5 and/or processing residues and/or in particle form of sufficient size, for example in a size of at least 20 µm, are removed and/or chips are retained. Such removal is in 7 not shown for simplicity.

The device 1 has in the 7 The embodiment shown has the cartridge 8 and thus corresponds to the 4 illustrated embodiment of the device 1.

The filter device 3 acts, in particular in contrast to the pre-filter device 14, as a chemical filtration unit which specifically removes the contaminants 5 due to specific binding to the filter material 4.

The contaminated cooling lubricant 2 or the contaminated cooling lubricant 2 are introduced into the filter device 3 via the inlet channel 9 and pass through the packing material 7 and the filter material 4.

In this case, the contamination 5 is removed from the cooling lubricant 2 by targeted or specific binding and the cooling lubricant 2 leaves the device 1 as cooling lubricant 2 with a reduced proportion of critical elements. This is again symbolized by the densely dashed ovals.

In a broader disclosure, the invention may also refer to any operating materials and/or process aids instead of the cooling lubricant.

Thus, in the 7 A continuous decontamination of a process aid for the processing device 10 can be achieved using the processing device 10 shown. The process aid is in particular the cooling lubricant 2.

In the filter material 4 remain in the 7 illustrated embodiment separated critical contaminations 18. The circuit of the cooling lubricant 2 or a flow direction of the cooling lubricant 2 is in 7 symbolized by broad arrows in unspecified coolant lines.

8th shows a schematic representation of another possible embodiment of the processing device 10.

In the 8th In the embodiment shown, the filter material 4 is used directly in the machine room 17 of the machining center 16. In particular, the filter material 4 is directly connected to the cooling lubricant supply 11, in the 8th In the embodiment shown, it is preferably introduced directly into the machine bed 12 of the machining device 10.

This results in a decontamination of the cooling lubricant 2 in the machine or the processing device 10 and/or the machine bed 12 by the filter material 4. During circulation of the cooling lubricant 2, decontaminated operating medium, in particular a decontaminated cooling lubricant 2, is again made available for the processing of the component 3. The decontaminated cooling lubricant 2 is in 8th symbolized by densely dashed ovals. Contamination 5 or contaminated cooling lubricant 2 is symbolized by a wide dashed line.

Furthermore, in the 8th In the illustrated embodiment, the filter material 4 again has two filter media 4a and 4b.

In the 3 , 4 , 5 , 7 and 8th the filter material 5 can comprise a pure metal and/or a metal oxide and/or other metal compounds and/or alloys and/or mixtures of different metal components for separating the contaminants 5.

The filter material 4 can comprise several filter media, i.e. several of the aforementioned substances.

It can be provided that the filter material 4 consists of pure metal and/or ultra-pure metal and/or metal oxide and/or alloys and/or mixtures of different metal components for separating the contaminants 5. In particular, it can be provided that the filter material 4 consists of a mixture of the aforementioned substances.

Preferably, the filter material consists of the 3 , 4 , 5 , 7 and 8th illustrated embodiments of an aluminum powder and/or an aluminum granulate and/or an aluminum foil.

Preferably, it can also be provided that the filter material 4 consists entirely or partially of transition metals and/or transition metal compounds and/or metal-non-metal compounds.

The 1 and 2 The lithography system explained, in particular the projection exposure system 100, 200 for producing a semiconductor component, generally has a plurality of components 13. In particular, the lithography system has the illumination system 101, 201 with the radiation source 102 and the optics 103, 109, 206, which in turn comprises at least one optical element 116, 118, 119, 120, 121, 122, Mi, 207. In the 1 and 2 In the lithography system shown, at least one of the components 13, in particular at least one of the optical elements 116, 118, 119, 120, 121, 122, Mi, 207 is at least partially produced using the device 1 as described in connection with the 3 , 4 , 5 , 7 , 8th and/or using the processing device 10 as described in the 7 and 8th Alternatively or additionally, at least one of the components 13, in particular at least one of the optical elements 106, 118, 119, 120, 121, 122, Mi,207 is at least partially manufactured using the method described in connection with the figures, in particular the 6 described procedure.

Within the scope of the invention, the component 13 can designate a single technical element of the projection exposure system 100, 200, for example a supporting structure, a functional structure and/or a mirror Mi, or also a group of several such elements, for example the illumination system 101, 201.

The 1 and 2 The projection exposure systems 100, 200 shown from a field of EUV (extreme ultraviolet) lithography and DUV (deep ultraviolet) lithography both benefit from the use of the device 1, the processing device 10 and the method explained.

List of reference symbols

1

contraption

2

Cooling lubricants

3

Filter device

4

Filter material

4a

first filter medium

4b

second filter medium

5

contamination

6

container

7

Packing material

8th

cartridge

9

Inlet channel

10

Processing facility

11

Cooling lubricant supply

12

Machine bed

13

Component

14

Pre-filter device

15

Pumping equipment

16

Machining center

17

Engine room

18

separated contamination

30

Feed block

31

Filter block

32

Return block

100

EUV projection exposure system

101

Lighting system

102

Radiation source

103

Lighting optics

104

Object field

105

Object level

106

Reticle

107

Reticle holder

108

Reticle displacement drive

109

Projection optics

110

Image field

111

Image plane

112

Wafer

113

Wafer holder

114

Wafer relocation drive

115

EUV / useful / illumination radiation

116

collector

117

Intermediate focal plane

118

Deflecting mirror

119

first facet mirror / field facet mirror

120

first facets / field facets

121

second facet mirror / pupil facet mirror

122

second facets / pupil facets

200

DUV projection exposure system

201

Lighting system

202

Reticle stages

203

Reticle

204

Wafer

205

Wafer holder

206

Projection optics

207

lens

208

Version

209

Lens housing

210

Projection beam

Wed

Mirror

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 102005021057 A1 [0008]
• EP 2283908 B1 [0009]
• DE 102008009600 A1 [0118, 0122]
• US 2006/0132747 A1 [0120]
• EP 1614008 B1 [0120]
• US6573978 [0120]
• US 2018/0074303 A1 [0135]

Claims (13)

Device (1) for filtering a cooling lubricant (2), comprising a filter device (3) with a filter material (4), characterized in that the filter material (4) is designed for the targeted removal by binding at least one contamination (5) from the cooling lubricant (2) which has a tendency towards hydrogen-induced outgassing. Device (1) according to Claim 1 , characterized in that the filter material (4) consists entirely or partially of at least one metal, in particular a high-purity metal, and/or at least one alloy of metals, in particular high-purity metals, and/or at least one metal compound and/or at least one metal-non-metal compound. Device (1) according to Claim 1 or 2 , characterized in that the filter material (4) is designed as a powder, as granules and/or as a film. Device (1) according to one of the Claims 1 until 3 , characterized in that the filter material (4) consists entirely or partially of at least one transition metal and/or at least one metal-non-metal compound and/or comprises a powder, granulate and/or film coated with at least one transition metal and/or at least one metal-non-metal compound. Device (1) according to one of the Claims 1 until 4 , characterized in that the filter material (4) consists entirely or partially of aluminium and/or one or more types of aluminium compounds, in particular an aluminium oxide. Device (1) according to one of the Claims 1 until 5 , characterized in that the contamination (5) comprises fluorine, chlorine, sulphur, phosphorus, silicon, sodium, magnesium, calcium, manganese, tin, zinc, indium and/or lead. Device (1) according to one of the Claims 1 until 6 , characterized in that - the filter device (3) has a container (6) and/or a cartridge (8) in which the filter material (4) is arranged, and/or - a packing material (7) is present for fixing the filter material (2). Method for filtering a cooling lubricant (2) by means of a filter device (3) with a filter material (4), characterized in that at least one contamination (5) which has a tendency towards hydrogen-induced outgassing is specifically removed from the cooling lubricant (2) by binding to the filter material (4). Procedure according to Claim 8 , characterized in that the filter material (4) in a container (6) and/or a cartridge (8) is introduced into a circuit of the cooling lubricant (2) of a processing device (10) such that at least a part of a volume of the cooling lubricant (2) flows continuously through the filter material (4), preferably an entire volume of the cooling lubricant (2) flows continuously through the filter material (4). Procedure according to Claim 8 or 9 , characterized in that the filter material (4) is introduced directly into a cooling lubricant supply (11), in particular a machine bed (12), of a processing device (10). Method according to one of the Claims 8 until 10 , characterized in that the cooling lubricant (2) is filtered during production of a component (13), in particular an optical element (116, 118, 119, 120, 121, 122, Mi, 207), of a lithography system. Processing device (10) for the low-contamination production of a preferably mechanical component (13), in particular a component (13) of a lithography system, wherein a device (1) according to one of the Claims 1 until 7 provided, and/or the processing device (10) for carrying out a method according to one of the Claims 8 until 11 is set up. Lithography system, in particular projection exposure system (100, 200) for producing a semiconductor component, with a plurality of components (13), in particular an illumination system (101, 201) with a radiation source (102) and an optics (103, 109, 206) which has at least one optical element (116, 118, 119, 120, 121, 122, Mi, 207), characterized in that at least one of the components (13), in particular at least one of the optical elements (116, 118, 119, 120, 121, 122, Mi, 207), is produced at least partially using a device (1) according to one of the Claims 1 until 7 and/or using a processing device (10) according to Claim 12 and/or using a method according to one of the Claims 8 until 11 is manufactured.

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