DE102008040160A1 - Treating optical elements by plasma, which is ignited to exist on surface of optical element to be treated and is present in cavity, for microlithography system, comprises forming a side from the cavity through the surface to be treated - Google Patents

Abstract

The method for treating optical elements (8) by plasma, which is ignited in order to exist on a surface (12) of the optical element to be treated and is present in a cavity (7), for microlithography system, comprises forming a side from the cavity through the surface to be treated, and moving the electrons of the plasma by an electrical alternating field in back and forth manner. A dimension of the cavity is selected in direction vertical to the surface, so that the average free path length of the electrons represents the dimension of the cavity and a hollow cathode effect is produced. The method for treating optical elements (8) by plasma, which is ignited in order to exist on a surface (12) of the optical element to be treated and is present in a cavity (7), for microlithography system, comprises forming a side from the cavity through the surface to be treated, and moving the electrons of the plasma by an electrical alternating field in back and forth manner. A dimension of the cavity is selected in direction vertical to the surface, so that the average free path length of the electrons represents the dimension of the cavity and a hollow cathode effect is produced. The electrical alternating field is produced by an electrode (4) partially facing the surface. The electrical alternating field is simultaneously applied for igniting the plasma and is a high-frequency alternating field with a frequency of 13.56 MHz. The optical element is turned as electrode for supplying the alternating field and/or as counter electrode of the electrode lying against the surface and is turned to earth potential or with a direct bias voltage or high-frequency bias voltage. The cavity is modified during the treatment. The cavity facing the surface is formed by a fitting form (6) formed to the surface to be treated, where the fitting form is partially complementarily reworked and/or partially complementary to the topography to be obtained. The fitting form has a metal surface or a metal lattice, and a surface or a lattice with a dielectric layer. The mesh size of the lattice is smaller or larger than the average free path length of the electrons. A corresponding plasma-cavity is intended at oppositely-lying sides of the optical elements to be treated. A plasma density of 10 1>5>cm ->3>or more is adjusted. The pressure of 0.001-20 mbar is selected. The ignition voltage of the plasma is selected in dependence of the pressure and the electrode distance, so that the ignition voltage is minimized. The optical element is dielectrically or electrically conductive at the surface and comprises Zerodur(RTM: Glass-ceramic) or quartz. Independent claims are included for: (1) a device for treating optical elements by plasma; (2) a voltage source; and (3) a fitting form.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The The present invention relates to a method and a device for processing optical elements, in particular for a microlithography system, or in general of objects by means of a plasma which is ignited, in order to work on the surface of the optical element or Object by plasma etching to carry out a material removal.

STATE OF THE ART

Out In the prior art are methods and apparatus for plasma etching of surfaces known. In the plasma etching process is generally caused by an electric field in one Plasma accelerated ions present on the surface to be processed so that they meet there upon encountering appropriate material from the surface Knock out. Due to the complicated conditions a stable Ignite plasma and at the same time a sufficiently high number of ions on the surface to be processed accelerate to ensure effective material removal there, is the plasma etching process only for specific use cases suitable and used in practice.

For the production of high quality optical elements, such as those in microlithography, it is necessary, on the one hand, to perform an absolutely exact and defined surface treatment, but also desirable, to do this in an effective way. For example, it is extreme costly worthwhile to manufacture optical elements for lithography, rework or repair faulty optical elements, around her for to be used in a lithography system and not disposed of to have to. However, such optical elements often have a coating, the for the surface treatment of the optical element must be removed again. For example this may be antireflection coatings and in particular to deal with metal fluoride layers and metal oxides.

DISCLOSURE OF THE INVENTION

OBJECT OF THE INVENTION

It It is therefore an object of the invention to provide a surface treatment method for optical To provide elements with which an accurate and effective Material removal on the surface of an optical element especially for the lithography is possible in an effective manner. It should be a corresponding Device simply constructed and a corresponding procedure easy be feasible.

TECHNICAL SOLUTION

These Task is solved by a method having the features of claim 1 and a device with the features of claim 19 and a fit according to claim 29. Further embodiments of the invention are the subject of the dependent claims.

The invention is based on the recognition that during plasma etching a particularly high etching rate can be achieved if the conditions of the so-called hollow cathode effect are fulfilled. Accordingly, the invention is based on the idea that an exact and sufficiently effective processing method for optical elements, in particular for the removal of coatings such as anti-reflection layers or metal fluoride layers such. As MgF ₂ , LaF ₃ and others and metal oxides such. As SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , HfO ₂ , ZrO _2, etc. is achievable, if the corresponding hollow cathode effect for the processing of lithographic, optical elements or of their surfaces can be used.

Corresponding It is proposed to ignite a plasma in a cavity whose one side through the surface of the optical element to be processed is formed and wherein the electrons in the plasma by an electric Alternating field to be moved back and forth. The extent of the cavity is chosen in at least one direction so that the corresponding Extension of the cavity has a dimension that the middle free path corresponding to the electrons in the plasma. By such a design namely the plasma is causes the electrons in the plasma due to the electrical Alternating field are moved back and forth, but at least a part the electrons in the plasma due to the dimensioning of the cavity, in which the plasma is present, does not reach the limiting surfaces and so on not removed from the plasma. This results in an increased excitation of gas molecules through the electrons to form ions, leaving a high ion density present in the plasma. This in turn allows for a higher number is accelerated by ions on the surface to be processed, so that the etching rate in one for an effective editing acceptable range arrives. This is the possibility given, even optical elements in an effective manner by a corresponding To process plasma.

However, it is necessary to have a corre sponding to create a cavity. This is achieved according to the invention by the use of fits which have a complementary surface to the surface of the optical element to be processed. Alternatively, the surface of the fit may also have a topography that is complementary to the shape to be achieved on the surface of the optical element to be processed. This makes it possible to structure the surface.

A appropriate fit is then at a suitable distance to the surface to be processed arranged to define a cavity in which the top mentioned conditions with respect to the mean free path for the electrons present in the plasma. Accordingly, a device according to the invention For processing optical elements, a plasma generating device and a voltage source for generating an alternating electric field in the area of the plasma and a receptacle for the optical to be treated Element on, with respect to which a corresponding fit arranged is. The fit can be detachable be included in the device to change the fit according to different optical elements to be processed to be able to make.

The Dimension of the cavity, which corresponds to the mean free path of the Corresponding electrons in the plasma can be perpendicular in one direction to the surface to be processed be provided so that in a large area of the surface to be processed corresponding Conditions for a high etching rate available. Furthermore The alternating electric field can also be vertical with a field direction to the surface to be processed be set to move the ions as perpendicular to the ions as possible working surface to accelerate.

Corresponding can be opposite the surface to be processed an electrode be provided, by means of which the alternating electric field over the Plasma can be generated.

Preferably can with the same electrode or by means of the same electrical Alternating field simultaneously ignited the plasma, so no separate plasma generating device is required or the plasma generating device and the device for generating the alternating electric field into each other are integrated. However, it is of course also conceivable means for generating the alternating electric field separate from the plasma generating device provided. So could For example, the plasma are ignited inductively, while the alternating electric field by a corresponding electrode arrangement is created.

The alternating electric field can be a high frequency or medium frequency alternating field be. The radio frequency (radio frequency RF) can with a frequency chosen from 13.56 MHz become. However, other frequencies are in the high or medium frequency range from a few kHz to several hundred MHz.

The to be processed optical element can either as a counter electrode of the alternating electric field or as an electrode to which the electrical Alternating field is generated, be provided while, for example, as a counter electrode Earth potential of the vacuum chamber or another electrode is selected. About that In addition, it is also conceivable that the optical element to be processed is applied with a bias voltage, which here either can be a DC voltage or an AC voltage, the alternating voltage again in the high or medium frequency range can be settled. Furthermore For example, the optical element to be processed may itself be at ground potential be.

The fitting, which defines the cavity opposite the surface of the optical element to be machined, in which the plasma is received and generated, may be formed entirely of a metallic material to serve as an electrode or at least part of an electrode. Instead of forming the fit as a one-piece metal body, the fit may also be constructed in two parts, wherein on the opposite side of the surface to be machined, a metal surface may be provided. In this case, the metal surface can either be firmly connected to the main body or can be designed to be removable in order to be able to provide differently shaped surfaces and different three-dimensional topographies corresponding to the different optical elements to be processed. Instead of the metal surface may also be a dielectric surface, for. B. be provided in the form of a coating of a metal surface. The dielectric material may comprise Al ₂ O ₃ or SiO ₂ .

In addition, can the fit also by a metal grid, which shaped accordingly three-dimensional can be formed. The grid may in turn have a dielectric coating or be formed of dielectric material. In the case of a grid should the mesh size of the grid not in the range of the middle free electronic path length, but be either smaller or larger.

The range of free electronic path length, which can be used for both the dimension of the cavity to be selected and for the determination of the mesh size of the metal grid, is in the range of ± 10% to ± 5% um the value of the mean free path of the electrons.

Of the Distance of the fit of the surface to be machined can in the range of 0.1 to 4 cm, in particular 0.5 to 2 cm or preferably 0.75 chosen to 1.5 cm become.

Around to make an effective processing of the optical element can, can be a two-sided editing or multi-sided editing made if corresponding plasma cavities are on two or more sides of the optical element to be processed are provided. Corresponding For example, the device may comprise two or more fits, wherein the Fitting shapes are designed to fit with a base electrode are electrically connected, so that the fits on a corresponding electrical potential can be brought.

Corresponding comprises the present invention according to a further aspect, for the independent and protection is sought in connection with the other aspects Also a matching fit, which is interchangeable in a corresponding Device can be used.

The plasma which is ignited may comprise various noble gases, such as argon, krypton, xenon, helium, but also gases such as nitrogen, oxygen, hydrogen and fluorine. In particular, a mixture of corresponding components is possible. In particular, argon-oxygen gas mixtures for layer etching and a mixture of argon, helium, nitrogen, oxygen and hydrogen for the removal of metal fluoride layers on dielectric substrates have proven to be favorable gas mixtures. The plasma may have a plasma density of more than 10 ¹¹ cm ^-3 , in particular 10 ¹³ cm ^-3 or 10 ¹⁵ cm ^-3 , while the pressure in the vacuum chamber in which the corresponding processes are carried out in the range of 0.001 to 20 mbar can be adjusted.

The remaining parameters of the plasma can in dependence Paschen's law, the ignition voltage of the plasma in dependence As far as possible minimizes pressure and electrode spacing.

With a corresponding method and a corresponding device is an effective way given, optical elements, which may be dielectric or conductive can, and in particular Zerodur or quartz, by plasma treatment to process and in particular surface layers, such as anti-reflection layers or Metal fluoride layers to remove.

BRIEF DESCRIPTION OF THE FIGURES

Further Advantages, characteristics and features of the present invention in the following detailed description of embodiments with the attached Drawings clearly. The drawings show here purely schematic Way in

1 an illustration of a vacuum chamber with plasma etching apparatus received therein according to the present invention;

2 a second embodiment of a plasma etching apparatus according to the invention;

3 a third embodiment of a plasma etching apparatus according to the invention;

4 a detailed view of the cavity between a fit and a surface to be machined;

5 a further detailed view of a cavity between a fit and a surface to be machined; and in

6 a third detail view of a cavity between a fit and a surface to be machined.

The 1 shows in a purely schematic representation of a vacuum chamber 1 , which via a pumping device 2 can be evacuated. Via a gas supply 3 can appropriate process gas in the vacuum chamber 1 be initiated. For the method according to the invention, the vacuum chamber is evacuated, for example to a pressure <10 ^-3 mbar, while subsequently process gases, for example from a mixture of argon and oxygen or a mixture of argon, helium, nitrogen, oxygen and hydrogen via the gas supply 3 in the vacuum chamber 1 be initiated. The corresponding supply lines for the individual gases are not shown for the sake of simplicity.

In the vacuum chamber 1 there is a plasma etching consisting of an electrode 4 connected to a high voltage source (RF voltage source) 5 which can generate a voltage at a frequency of 13.56 MHz at the electrode.

On the electrode 4 is a fit 6 provided a three-dimensional curved surface 12 and can be made of a metallic material, such as titanium, aluminum, tungsten, molybdenum, tantalum or silicon, or of the above-mentioned materials with SiO ₂ coating.

The three-dimensional curved surface 12 the fit 6 For example, in the embodiment shown, a spherically curved concave indentation is complementary to the spherical surface of a surface of the lens to be machined 8th is trained.

The optical lens 8th , which in the embodiment of the 1 is shown as an object to be edited, is opposite the fit 6 or the three-dimensionally curved surface 12 arranged at a distance, leaving a gap 7 results. In the gap 7 is due to the alternating electric field at the electrode 4 opposite to, for example, at ground potential optical lens 8th a plasma ignited. Through the alternating electric field, which via the electrode 4 or the fit 6 in the gap 7 is generated, the charge carriers, which are located in the plasma, according to the applied field moves. The distance d between the fit 6 and the object to be processed or the optical lens 8th is now chosen so that the mean free path of the electrons in the plasma is approximately the distance d between the surface of the fit 6 and the surface to be processed of the optical lens 8th or the width of the gap 7 equivalent. However, this does not mean that there must be an exact and exact match between mean free path and distance d, but it is sufficient if the distance d is chosen in a range around the mean free path of the electrons, for example in a range of ± 10% or ± 5%. The choice of the distance d in the region of the mean free path of the electrons causes a significant proportion of the electrons on the plasma due to the alternating motion or alternating acceleration in opposite directions due to the electric field none of the cavity 7 reaches bounding surfaces, so that many electrons for the excitation of ions, which are required for plasma etching arise. As a result, a high plasma or ion density is achieved, which in turn leads to high etching rates on the surface of the optical element to be processed 8th leads when ions are accelerated by the electric field on the surface to be machined.

By the fit 6 can be ensured in a simple manner that usually not even trained optical elements with their curved surfaces can also be effectively processed by plasma etching. In particular, it has been found that the corresponding method or apparatus for the removal of coatings on optical elements, such as antireflection layers and in particular metal fluoride layers, is particularly suitable. Such removal of antireflection layers is required, for example, in the post-processing of optical elements or in their repair. This is particularly important for optical elements in Mirkolithographieanlagen, so for example lighting systems or projection lenses of lithography systems, because the local optical elements are made very expensive and thus are very expensive. Accordingly, it is worth the effort for the repair or post-processing already applied layers, such as anti-reflection layers to remove again. However, here a method must be provided, which allows effective and accurate processing. This is now the case with the present invention.

The 2 and 3 show two further embodiments of plasma etching, for example, in the vacuum chamber 1 can be operated. For simplicity, in these examples, the 2 and 3 however, the vacuum chamber has been omitted accordingly.

In the embodiment of the 2 is a plane-parallel plate 8th represented as an object to be processed. This is about an insulating body 11 on the electrode 4 arranged and held there.

For a two-sided processing on opposite sides of the substrate to be processed 8th To make, are two fits 6a and 6b provided, the two-piece with a body 10 and a fit surface 9 are formed. This two-part embodiment has the advantage that the main body with the holder on the electrode 4 for different fitting surfaces 9 can be maintained while only the fitting surface 9 must be changed for different substrates to be treated. The fit surface 9 can z. B. made of SiO ₂ , or of metal, which is coated with SiO ₂ .

The electrode 4 is again with a high frequency power source 5 connected, which by generating a high-frequency alternating electric field in the region of the column 7 a plasma formed on both sides of the optical element or the object to be processed, wherein the distance between the surfaces of the object to be processed 8th and the opposite metal surfaces 9 the fits 6a and 6b corresponds to the mean free path of the plasma, so that high etching rates on the surfaces of the object 8th occur. Like the embodiment of 2 shows, the fit in a flat object to be machined can also be designed to be flat and smooth.

The 3 shows a further embodiment of a corresponding plasma etching, which in turn in a vacuum chamber, as in the embodiment of the 1 is shown can be arranged.

The plasma etching apparatus of 3 also corresponds with regard to the shape of the object to be processed 8th the embodiment of the 1 , because here too an object is processed, which takes the form of an optical lens 8th having. However, in the embodiment of the 3 the optical lens 8th not only one-sided as in the embodiment of 1 , machined, but two - sided, similar to the embodiment of 2 , Accordingly, again two fitting shapes are provided adjacent to the surfaces of the optical lens to be machined 8th are arranged and between this and themselves each have a gap 7 form, in which the corresponding plasma is ignited. Also the gap 7 , in turn, the contour of the surface of the optical element 8th follows, has a width which corresponds to the average free path of the electrons at the applied high-frequency AC voltage, the selected pressure and the corresponding gas.

In contrast to the embodiment of 2 are in the embodiment of the 3 the fits 6a and 6b again formed in one piece. These too are for establishing an electrical connection with the electrode 4 connected, in turn, with the high frequency power source 5 connected to a high frequency alternating potential at the electrode 4 to apply. By the electrical connection of the fits 6a and 6b Forms on the metallic surfaces of the fits 6a and 6b a corresponding potential, which is opposite to the lying at ground potential optical element 8th allows a sufficient voltage difference to ignite a plasma.

The optical element 8th is in the embodiment of 3 also by an insulating body 11 from the electrode 4 separated.

The object to be edited 8th may be subjected to a bias voltage instead of the ground potential, which may be formed either as a DC voltage or as a high-frequency AC voltage.

The fits 6 respectively. 6a and 6b can either consist of a solid metal body or integrally or interchangeably arranged layers, such as layers of metal, SiO ₂ or of another dielectric material, such as. B. Al ₂ O ₃ , have. In addition, it is also possible to form the fits as a metal grid or with SiO ₂ or other dielectric materials coated grid. In such an embodiment, however, it should be noted that the mesh size of the metal grid is not in the order of magnitude of the free path of the electrons, since the plasma can penetrate the metal grid and then correspondingly high etch rates would occur on the metal grid.

The 4 to 6 show in more detail different combinations of surfaces of the object to be processed 8th and the fits 6 ,

As in the example of 4 can be seen, the fit can be 6 sharpen 12 or have other elevations, which in contrast to the recessed surface of the fit the desired distance d in the order of the mean free path of the electrons in the gap 7 have ignited plasmas. Accordingly, in this area, the etching rate by on the surface of the object to be processed 8th impinging ions higher, so that there is an increased erosion 13 forms, as indicated by the dashed hollows. Accordingly, in this way, the surface of the object to be processed 8th be structured, as for example in the 6 is shown. Here, the surface of the fit has a textured surface with protruding and recessed areas and steps. The area closest to the surface to be machined or the region which projects most is first brought into the position such that the distance d from the surface to be machined is the mean free path of the electrons in the gap 7 ignited plasma corresponds, so that there the strongest erosion is to be expected. Once the removal has led there that the optimal distance d has been lost with high etching rate due to the material removal, the fit 6 , as in 4 indicated by the arrow top right, be tracked to restore the optimal distance d. This can be done continuously with the speed of material removal. At the same time but in another surface area another projection or another stage 14 the fitting surface the optimal distance d to the surface of the object to be machined 8th reach, so that there takes place a material removal. This can then be continued until the corresponding contour of the fit on the surface of the object to be processed 8th is transferred.

This condition is for example in the 5 for corrugated surfaces of the object to be processed 8th and the fitting surface 6 achieved so that then over the entire surface area when setting the optimal distance d, a high surface removal of the object to be processed 8th takes place and the structuring can be ended.

Although the present invention is based on It is clear to those skilled in the art that the invention has been described in detail with reference to the attached embodiments, but modifications or additions, in particular by a different combination of all shown features or the omission of individual features, is possible without the To leave the scope of the appended claims. In particular, the present invention includes any combination of individual features.

Claims (36)

Method for processing optical elements ( 8th ) by means of a plasma which is ignited to be present at the surface to be processed of the optical element, characterized in that the plasma in a cavity ( 7 ), at least one side of which is formed by the surface of the optical element to be processed, the electrons of the plasma being reciprocated by an alternating electric field, and wherein at least one dimension of the cavity is selected such that the mean free path of the Electrons corresponds to the dimension of the cavity and so a hollow cathode effect is generated. Method according to claim 1, characterized in that that the dimension is selected in the direction perpendicular to the surface to be machined. A method according to claim 1 or 2, characterized in that the alternating electric field through one of the surface to be machined at least partially opposite electrode ( 4 . 6 ) is produced. Method according to one of the preceding claims, characterized characterized in that the alternating electric field at the same time Ignite of the plasma is used. Method according to one of the preceding claims, characterized in that the alternating electric field is a high-frequency alternating field, in particular with a frequency of 13.56 MHz. Method according to one of the preceding claims, characterized in that the optical element to be processed as an electrode for providing the alternating electric field and / or as a counter electrode of one of the surface to be machined opposite electrode ( 4 . 6 ), with which the alternating electric field is generated, or is connected to ground potential or with a DC or high frequency bias voltage. Method according to one of the preceding claims, characterized characterized in that the cavity is changed during processing. Method according to one of the preceding claims, characterized characterized in that the cavity opposite to be machined surface at least partially complementarily reworked by one of the surface to be machined and / or at least partially complementary formed to fit the topography trained fit is. Method according to claim 8, characterized in that the fit ( 6 ) has a metal surface or a metal mesh and / or is formed of metal, in particular of at least one of the components contained in the group containing titanium, aluminum, tungsten, molybdenum, silicon and tantalum. Method according to claim 8, characterized in that the fit ( 6 ) comprises a surface or a lattice having a dielectric layer formed in particular of at least one of the components contained in the group comprising SiO ₂ and Al ₂ O ₃ . Method according to claim 9 or 10, characterized that the mesh size of the grid is smaller or larger than the mean free path of the Electron selected becomes. Method according to one of the preceding claims, characterized characterized in that a corresponding plasma cavity at several Pages of the processed optical element, in particular to face Pages is provided. Method according to one of the preceding claims, characterized marked that the plasma is at least one component of the group includes, the noble gases, argon, krypton, xenon, helium, nitrogen, Contains oxygen, hydrogen and fluorine. Method according to one of the preceding claims, characterized in that a plasma density of 10 ¹¹ cm ^-3 or more, in particular 10 ¹³ cm ^-3 or more, preferably 10 ¹⁵ cm ^-3 or more is set. Method according to one of the preceding claims, characterized characterized in that the pressure is in the range of 0.001 to 20 mbar chosen becomes. Method according to one of claims 4 to 15, characterized in that the ignition voltage of the plasma as a function of pressure and Electrode distance is selected so that the ignition voltage is minimized. Method according to one of the preceding claims, characterized in that the optical element ( 8th ) is dielectrically or electrically conductive, especially Zerodur or quartz, especially on the surface. Method according to one of the preceding claims, characterized in that the plasma treatment for removing surface layers, in particular antireflection layers, preferably metal fluoride layers, in particular MgF ₂ , LaF ₂ and / or metal oxides, in particular SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , HfO ₂ , ZrO _{2 is} used. Apparatus for processing optical elements by means of a plasma, comprising a plasma generating device ( 4 . 5 . 6 ) and a recording ( 11 ) of an optical element to be treated, in which the optical element to be treated is arranged in the region of the plasma generating device such that a plasma can be ignited for plasma etching of a surface of the optical element, wherein a voltage source ( 5 ) is provided for generating an alternating electric field in the region of the plasma, characterized in that at least one fit ( 6 ) is provided, which opposite one to machined surface is arranged to a cavity ( 7 ) in which the plasma can be ignited. Device according to claim 19, characterized in that the fit ( 6 ) has a three-dimensional topography on the opposite side of the optical element to be processed. Device according to claim 20, characterized in that that the three-dimensional shape is a spherical or aspherical concave Indentation is. Device according to one of claims 19 to 21, characterized in that the fit ( 6 ) has one of the surface to be machined at least partially complementary reworked and / or at least partially formed to the topography to be achieved surface. Device according to one of claims 19 to 22, characterized that the fit is a metal surface or has a metal grid and / or of metal, in particular is formed from at least one of the components which in the Group containing titanium, aluminum, tungsten, molybdenum, silicon and tantalum. Device according to one of claims 19 to 23, characterized that the fit opposite with their surface to be machined surface at a distance of 0.1 cm to 4 cm, in particular 0.5 cm to 2 cm, preferably 0.75 cm to 1.5 cm opposite the surface to be processed can be arranged. Device according to one of claims 19 to 24, characterized in that the fit ( 6 ) is arranged interchangeable and / or movably arranged, so that the distance between the surface to be machined and fit is variable. Device according to one of claims 19 to 25, characterized that two fits are provided, which between them recording for the include the object to be edited. Device according to one of claims 19 to 26, characterized that the plasma generating device has a high frequency (RF) or middle frequency Voltage source ( 5 ), wherein the fit is part of an electrode connected to the voltage source. Device according to one of claims 19 to 27, characterized that the fit during the plasma treatment is arranged to be movable. A fit for use in a device according to any one of claims 19 to 28, comprising a support for mounting on or on an electrode and a layer ( 9 ) or a grid having a three-dimensional topography, wherein the layer or the grid has a connection for the electrically conductive connection to the electrode and are formed from metal and / or a dielectric material. Fit according to claim 29, characterized that the three-dimensional topography is at least partially complementary to one to be processed object and / or at least partially to that at one Object is designed to achieve topography. A fit according to claim 29 or 30, characterized that the fit is completely off Metal is formed and / or metal comprises, which at least a component of the group comprising titanium, aluminum, tungsten, Molybdenum, silicon and tantalum. Fit according to one of claims 29 to 31, characterized in that the dielectric material as a coating of a metal surface or egg There is a metal grid. A fit according to any one of claims 29 to 32, characterized in that the dielectric material comprises at least one component from the group comprising SiO ₂ and Al ₂ O ₃ .