DE102007039407A1 - Composite body manufacturing method for use in area of immersion lithography, involves treating contact surfaces, such that contact surfaces are free from mono-layered or multi-layered layer of water molecules - Google Patents

Abstract

The method involves providing two components (1, 2) with respective contact surfaces provided for connection. The contact surfaces are treated in such a manner that the contact surfaces are free from a mono-layered or multi-layered layer of water molecules. The contact surfaces are brought together for optical contacting of the component (1) e.g. optical unit, to the component (2) to manufacture a composite body from the two components. The component (1) has calcium fluoride crystal, lutetium-aluminum garnet-crystal, quartz glass, polycrystalline-spinel or spinel-ceramic. Independent claims are also included for the following: (1) a contacting device for implementing dry contacting of bodies (2) a composite body having two bodies.

Description

TECHNICAL AREA

The The invention relates to methods for producing a composite body, a Ansprengvorrichtung for implementation a Ansprengung, and a composite body of a first body and a second body, being the first body and the second body are sprinkled together.

STATE OF THE ART

In known lithographic optics, also in the field of immersion lithography, in many cases crystals, for example calcium fluoride (CaF ₂ ) crystals, are used. As immersion liquid, high-purity water is introduced between the wafer to be exposed and the objective in conventional immersion lithography systems.

high purity However, water is known to attack the surfaces of optical Components, especially crystal and glass surfaces, strong at. So come the crystals used in contact with the highly pure Water, they are so damaged in no time so that the lithographic device must be taken out of service.

For this reason, a protection element for protection against direct contact of the crystal with the immersion liquid is often interposed between the crystal and the water. As a material for the protective element, for example, pure quartz glass in the form of a lens or a plate in question, since quartz glass on the one hand in comparison to other non-birefringent materials has relatively high resistance to the chemical effects of water, and on the other for those in lithography Frequently used wavelengths 193 nm and 248 nm is transparent. Quartz glass consists only of a single compound, namely the glass framework, which has a high resistance. For other glasses, however, the glass formers are chemically attacked because the glass framework consists of SiO ₂ .

to Production of an optical contact between the protective element and the crystal optical element may be, for example, a chemically less aggressive immersion can be used. alternative For this purpose, the protective element can be firmly connected to the crystal element become.

A conventional connection method is for example in the document US 2003/0079823 A1 disclosed. In the bonding method, the surface of the crystal is activated by means of a hydroxide solution, so that reactive end groups are formed on the opposite surfaces. Subsequently, the two surfaces are brought into contact. When bonding the surfaces, covalent bonds are formed between the activated surfaces.

Another connection method consists of wringing the protective element against the optical crystal element. An impingement is understood as a spontaneous connection or attachment of two bodies. The compound by wringing can take place between two bodies of the same material or of different materials. When wringing, two surfaces are approximated to make a connection. Such a connection takes place by means of intermolecular interactions, namely by means of van der Waals forces. In contrast, formed in the above-mentioned document US 2003/0079823 A1 covalent bonds between the surface molecules of the bodies to be joined. Covalent bonds differ in magnitude by van der Waals interactions.

The biggest problems with composite bodies produced by wringing two bodies of different materials are due to the divergent coefficients of thermal expansion of the materials. For example, while the mean thermal expansion coefficient of quartz glass is 0.54 × 10 ^-6 / ° C, calcium fluoride has an average thermal expansion coefficient of 18.4 × 10 ⁶ / ° C. The coefficients of expansion therefore differ by a factor of 34.

For example results in a connection surface with a diameter of 100 mm between these two materials a shear of 1.8 μm / ° C over the whole length or 0.9 μm / ° C radially from the middle of the interface to the edge.

There in the manufacture (e.g., in a heat treatment of the composite) and When using the lithography optics high temperature differences occur can, to lead the different coefficients of expansion to high shear forces, the up to the replacement the impact can affect. Repeated passing through a temperature change worsens the Impingement under circumstances so much so that ultimately the optical crystal component gets destroyed.

TECHNICAL TASK

Based on this, it is the object of the present invention to provide a safe and durable To establish a connection between two components, in particular between a component made of a calcium fluoride (CaF ₂ -) crystal, and a component made of quartz glass. In particular, an improved Ansprengung be proposed by the atomic bonding forces sufficient for a secure and durable connection in a composite body despite different temperature coefficients and high shear forces occurring in the transition layer.

TECHNICAL SOLUTION

These Task is solved by a method according to any one of claims 1, 15, 21, by the provision an Ansprengvorrichtung according to claim 27, and by a composite body according to Claim 29.

• a) Bereitstellen eines ersten Körpers und eines zweiten Körpers mit jeweils einer für die Verbindung vorgesehenen Kontaktflache;
• b) Behandeln der Kontaktflächen derart, dass die Kontaktflächen von einer monomolekularen oder mehrlagigen Schicht von Wassermolekülen befreit werden; und
• c) Zusammenbringen der von Wassermolekülen befreiten Kontaktflachen zum Ansprengen des ersten Körpers an den zweiten Körper zur Herstellung eines Verbundkörpers aus dem ersten Körper und dem zweiten Körper.

One of the methods according to the invention for producing a composite body comprises the following steps:

• a) providing a first body and a second body, each with a contact surface provided for the connection;
• b) treating the contact surfaces such that the contact surfaces are freed from a monomolecular or multilayered layer of water molecules; and
• c) contacting the water molecules liberated contact surfaces for wringing the first body to the second body to produce a composite body of the first body and the second body.

at usual Ansprengverfahren are the surfaces of the components to be joined, too if the blasting is carried out in dry rooms, nevertheless wetted with a monomolecular layer of water, there under the usual Conditions every dry surface within the shortest possible time Time is wetted. After the erosion, the two partners stand in places in contact. Between the contact points form however cavities in which the previously existing as monomolecular layer, displaced during the blasting Water, collects. This trapped water leads to chemical reactions the crystal, in particular to a corrosion of the crystal surface.

According to the invention this way a connection between two components by an anhydrous Impounding made. In this connection one can also of speak of a "dry" bleaching. This creates a permanent connection between the components, even in the presence of high shear forces and the influence of UV laser radiation reached.

Since van der Waals forces are known to act between the surfaces of the bodies to be joined during wringing, the negative effects of water molecules present between the layers are significant. Van der Waals forces are orders of magnitude smaller in magnitude than the forces encountered in covalent bonds (such as in the US Pat US 2003/0079823 A1 described), so that the influence of the disturbing water molecules is greater. The connection quality is thus significantly improved by a dry blasting.

One Composite produced in this way can, for example, in immersion lithography. I am the first body, for example an optical crystal may be connected to a second body, for example one Quartz lens can be connected to the crystal before a chemical Reaction with the immersion liquid (i.d.R. water).

To the removal of the monomolecular water layer from the bonding surfaces of the bonding partners the two partners to be pressed against each other are united. This is done according to the invention under Conditions under which there is no new formation of a water layer on the surfaces comes. The wringing is so in the absence of water, even while avoiding the formation of a monomolecular water vapor layer on the contact surfaces carried out.

The Removal of the water layer before the Ansprengvorgang should of course possible to be complete. Of course However, it is unavoidable that individual water molecules or Regions with water molecules on the surface remain. A Removal of the water layer in the sense of the invention means that no water layer over extends a substantial portion of the surfaces to be joined, and after Connection no larger water reservoirs, which in a conventional Forming an injunction arise.

In particular, as the first body, a crystal, in particular a calcium fluoride (CaF ₂ ) crystal, is provided as the optical element.

The first body may preferably comprise a lutetium aluminum garnet (LuAG, Lu ₃ Al ₅ O ₁₂ ) crystal.

In a further embodiment, the first body comprises a material comprising spinel (MgAl ₂ O ₄ ), in particular polycrystalline spinel or spinel ceramic.

Of the first body can in another embodiment Include quartz glass.

When second body may be a protective element made of quartz to protect the first body in contact with a liquid, especially with water. Quartz has favorable optical Property and high chemical stability to water can and does so protect the crystal effectively from contact with water. The formed as a crystal-quartz composite body optical component can, for example, in the immersion lithography be used. The quartz body can e.g. be formed as a lens or plate.

The Matching the contact surface of the first body with the contact surface of the second body is preferably carried out in a vacuum. This is a possibility according to the invention, a on the contact surfaces educated monomolecular water layer to remove the new formation a monomolecular layer of water and so the inclusion of water between the contact surfaces to prevent. A vacuum in the range of some mbar ensures that the water from both the surface of the crystal body as well as from the surface of the quartz glass body Will get removed.

In front the implementation of step c) is preferably at least one of the contact surfaces of first body and the second body at least about a partial area of the contact area provided with a coating. In particular, before wringing a vapor deposition layer applied to the crystal surface, with the one another optical element, e.g. the protective element, then connected becomes.

Thereby the effect is achieved that trapped between the contact surfaces Residual water is bound. No applied layer is perfect compact, but has errors, such as about 0.3-3 vol% Cavities. These cavities However, they themselves tend to be very strong, a monomolecular water layer build up or take up gases. Thus, residual water is due to the porosity of the layer in the cavities recorded and the contact surface kept dry during blasting. As a result, they are the optical element and the protective body connecting atomic forces dominant and keep the components in contact with temperature fluctuations.

Preferably the coating is as a quartz layer, especially on the first Body, upset. Both contact surfaces should as possible when wringing dry, i. preferably also freed from the monomolecular water layer on the contact surfaces be. Small traces of water that can still be present through the porosity absorbed or captured the applied layer.

Especially the coating has a thickness of 30 nm to 50 nm.

The coating can be applied by vapor deposition in a vacuum recipient on the body. For example, the contact surface can be given a virtually cold coating. The recipient can then be flooded, eg with N ₂ .

Prefers is a seal in the edge region of the contact surfaces for Sealing against the ingress of water molecules at the edge of the contact surfaces in arranged the connection area between the first body and the second body. The porosity the applied layer acts at the edge of the contact surface negative by the tendency to bind water, a diffusion of water vapor and penetration of water vapor in the connection region between the optical element and the protective body promotes.

The Sealing can cause a shear between the protective body and allow the crystal to be elastic. For a freedom of movement the connected body each other can also be an elastic monolithic joint within of the composite body to care.

The method step c) can also be carried out according to the invention in an atmosphere of an inert gas or a gas mixture which is substantially free of water molecules. Of course, the contact surfaces must first have been freed from water and must no longer wet before being introduced into the gas atmosphere. This may be, for example, a helium-oxygen mixture having a water vapor pressure of at most 5 × 10 ^-6 mbar, which can be brought to a value of, for example, 1 × 10 ^-6 mbar by using the drying agent.

During the execution of step c), at least temporarily UV radiation and / or an ionized gas flow may occur on at least a portion of the contact surfaces (FIG. 1' . 2 ' ). The irradiation is initially perpendicular to the contact surfaces, which are then facing each other for exposure and brought into contact.

A water-vapor pressure of less than 5 × 10 ^-6 mbar, in particular of less than 1 × 10 ^-6 mbar, preferably prevails in the atmosphere from the inert gas or gas mixture. To produce very low vapor pressures, a drying agent such as P ₂ O ₅ can be used.

The method step c) is in particular in an evacuated recipient under at least temporary bombardment of at least a portion of Contact surfaces of the first body and / or the second body carried out with ions.

The Matching the contact surface of the first body with the contact surface of the second body can be accomplished by means of a mechanical turning device.

• a) Bereitstellen eines ersten Körpers und eines zweiten Körpers mit jeweils einer für die Verbindung vorgesehenen ersten bzw. zweiten Kontaktfläche;
• b) Durchführung einer nassen Ansprengung zwischen der ersten Kontaktfläche und der zweiten Kontaktfläche zur Bildung eines Verbundkörpers;
• c) Einbringen des Verbundkörpers in ein Volumen einer Kammer, das mit einem inerten Gas oder Gasgemisch, das im Wesentlichen von Wassermolekülen frei ist, gefüllt ist;
• d) teilweises Lösen der nassen Ansprengung in einem ersten Teilbereich der Kontaktflächen; und
• e) Entfernen der im ersten Teilbereich zwischen den Kontaktflächen bzw. an den voneinander gelösten Kontaktflächen angeordneten Wassermoleküle.

Another method according to the invention for producing a composite body comprises the following steps:

• a) providing a first body and a second body, each having a first or second contact surface provided for the connection;
• b) performing a wet blasting between the first contact surface and the second contact surface to form a composite body;
• c) introducing the composite into a volume of a chamber filled with an inert gas or gas mixture substantially free of water molecules;
• d) partial release of the wet impact in a first portion of the contact surfaces; and
• e) removing the water molecules arranged in the first subregion between the contact surfaces or at the contact surfaces which are detached from one another.

Prefers is the exposure in step d) by actuation of a micrometer screw, in an outdoor area on the first body or the second body attacks, solved.

In Step e) can through the water molecules the flow of a dry gas, in particular of nitrogen, through the gap between the dissolved contact surfaces in the first subarea are removed.

• f) Wiederansprengung der getrockneten Kontaktflächen (1', 2') im ersten Teilbereich (1b, 2b) der Kontaktflächen

durchgeführt werden.After performing step e), the step

• f) Reclaiming the dried contact surfaces ( 1' . 2 ' ) in the first subarea ( 1b . 2 B ) of the contact surfaces

be performed.

• g) teilweises Lösen der Ansprengung über einen zweiten Teilbereich der Kontaktflächen; und
• h) Entfernung der zwischen den Kontaktflächen im gelösten zweiten Teilbereich bzw. an den im zweiten Teilbereich voneinander gelösten Kontaktflächen angeordneten Wassermolekülen

durchgeführt werden. Der zweite Teilbereich stimmt mit dem ersten Teilbereich nicht überein, d.h. der zweite Teilbereich ist noch nass angesprengt. Durch Lösen und Trocknen in diesem Bereich werden so auch die Wassermoleküle in dem vorher noch nass angesprengten Teil der Kontaktfläche entfernt.After step f), the steps

• g) partially releasing the blasting over a second portion of the contact surfaces; and
• h) removal of the water molecules arranged between the contact surfaces in the dissolved second subregion or at the contact surfaces which are detached from one another in the second subregion

be performed. The second sub-area does not match the first sub-area, ie the second sub-area is still wet sprinkled. By loosening and drying in this area as well as the water molecules are removed in the previously wet-sprung part of the contact surface.

The Steps g) and h) are preferably repeated several times to form water molecules and a water layer completely remove from the intermediate area between the contact surfaces. So will the wet blasting gradually transformed a dry blasting.

• a) Bereitstellen eines ersten Körpers und eines zweiten Körpers mit jeweils einer für die Verbindung vorgesehenen ersten bzw. zweiten Kontaktfläche;
• b) Durchführung einer nassen Ansprengung zwischen der ersten Kontaktfläche und der zweiten Kontaktfläche zur Bildung eines Verbundkörpers;
• c) Einbringen des Verbundkörpers in ein Volumen einer Kammer, das mit einem inerten Gas oder Gasgemisch, das im Wesentlichen von Wassermolekülen frei ist, gefüllt ist;
• d) Vollständiges Lösen der Ansprengung über die gesamte Kontaktfläche zwischen dem ersten Körper und dem zweiten Körper; und
• e) Entfernen der zwischen den Kontaktflächen bzw. an den voneinander gelösten Kontaktflächen angeordneten Wassermolekülen.

Another method according to the invention for producing a composite body comprises the following steps:

• a) providing a first body and a second body, each having a first or second contact surface provided for the connection;
• b) performing a wet blasting between the first contact surface and the second contact surface to form a composite body;
• c) introducing the composite into a volume of a chamber filled with an inert gas or gas mixture substantially free of water molecules;
• d) completely releasing the impact over the entire contact area between the first body and the second body; and
• e) removing the water molecules arranged between the contact surfaces or at the contact surfaces which are detached from one another.

To the step d) can be the distance between the separated contact surfaces be set.

Especially is a distance between 0.25 mm and 0.75 mm, in particular of about 0.5 mm, adjusted. This will prevent dust and other Impurities reach the contact surfaces.

Of the Distance is, for example, by means of at least one spacer set.

In Step e) can through the water molecules the flow of a dry gas, especially through the flow of nitrogen, through the interstice of the separated contact surfaces become.

• f) Wiederansprengung des ersten Körpers an dem zweiten Körper durch Kontaktherstellung zwischen den getrockneten Kontaktflächen;

durchgeführt werden.After step e), the step

• f) restituting the first body to the second body by making contact between the dried contact surfaces;

be performed.

An Ansprengvorrichtung invention for performing a dry Anspren tion, in particular for carrying out a dry blasting, in particular according to a method according to one of the preceding claims, comprises an up / down closed cavity with a flooding volume in the upper / lower region of the cavity, at least one impingement area arranged in the flooding volume for wringing a first body a second body, and at least one supply line for supplying a flooding gas for filling the flooding volume.

The Ansprengvorrichtung has in a preferred embodiment a UV irradiation on, which during a blasting in Contact to be made contact surfaces at least temporarily before and during the Ansprengvorgangs irradiated. In particular, the surfaces are first irradiated vertically, then turned to each other and brought into contact.

One Compound according to the invention comprises a first body and a second body, wherein the first body and the second body are sprinkled together. The area of the contact area between the first body and the second body is essentially free of water molecules.

Between the first body and the second body In particular, a layer is arranged, the cavities for Trapping in the contact area between the first body and the second body arranged, the contact area contaminating water molecules.

in the Edge area of the connection surface between the first body and the second body can a seal for sealing the connection area from penetration of water molecules in be arranged the connection area.

BRIEF DESCRIPTION OF THE DRAWINGS

Further Features and advantages of the invention will become apparent from the description preferred embodiments and its associated Drawings. The figures show:

1a two prior art surfaces to be abutted together;

1b two prior art surfaces peeled together;

2 a composite body according to the present invention;

3 a perspective view of a workplace according to the invention;

4 : A view of the workplace according to the invention 3 from above;

5a - 5c : a time sequence of a Ansprengvorgangs;

6 a vertical sectional view of a workplace according to the invention;

7 a vertical sectional view of another workplace according to the invention;

8th a sectional side view of an ergonomic workplace according to the invention;

9 : a front view of the ergonomic workplace according to the invention 8th ;

10a - 10c : a time sequence of a Ansprengvorgangs invention;

11 a storage container according to the present invention;

12a a side view of an apparatus for carrying out a method according to the invention;

12b : a view of a composite body while performing the on the basis of the 12a illustrated method; and

13 a side view of an apparatus for carrying out a further inventive method.

EMBODIMENTS THE INVENTION

The 1a shows greatly enlarged a calcium fluoride crystal 1 with a surface 1' and a quartz lens 2 with a surface 2 ' , The surfaces 1' and 2 ' that have microscopic bumps have been prepared for conventional brushing. When separated, each of the surfaces is 1' . 2 ' of the calcium fluoride crystal 1 or the quartz lens 2 with a monomolecular layer 3 wetted from water vapor.

By contacting the prepared for a conventional Ansprengung surfaces 1' . 2 ' can the body 1' and 2 ' be joined together to form a composite body 1 . 2 to form, as in the 1b shown.

The 1b However, it also clarifies the problems with conventional Ansprengverfahren for connecting a calcium fluoride crystal 1 with a quartz lens 2 , After joining, the connection partners stand 1 and 2 , due to the microscopic unevenness of the surfaces, not continuously, but only at certain contact areas in contact. Between the contact areas arise water inclusions 4 . 4 ' . 4 '' by displacing the water vapor of the monomolecular layers 3 , The water inclusions 4 . 4 ' . 4 '' can cause corrosion of the crystal 1 to lead. When strong shearing forces are applied, for example caused by temperature fluctuations, the connection between the partners can become 1 and 2 to solve.

Because of the presence of the monomolecular water layer 3 on the surfaces 1' and 2 ' the liaison partner leading to the water inclusions 4 . 4 ' . 4 '' As the water molecules significantly interfere with the relatively weak van der Waals forces that occur between the surfaces during the blasting, a satisfactory bond is generally not possible to reach.

According to the invention, therefore, the monomolecular steam layer 3 from the connection surfaces 1' and 2 ' the connection partner 1 respectively. 2 removed before the Ansprengvorgang. This can be done in different ways.

A first possibility is to create a vacuum before and during the blowing process, which ensures that the surfaces 1' and 2 ' be largely freed of water vapor and remain free.

In this way, water inclusions 4 . 4 ' . 4 '' and their negative impact on the connection of the partners 1 and 2 avoided. The compound is safe and durable even when shear forces occur or when exposed to UV laser radiation.

The following is an exposure in which the water vapor layer 3 at least to a large extent removed from the surfaces prior to the blasting was referred to as "dry" bleaching.

A inventive "dry" Ansprengung can be However, without the generation of a vacuum realize. First, will a quartz plate, later to a crystal to protect the crystal from water blasted should be cleaned. These are, for example, anhydrous Acetone, alcohol, ether or other suitable, absolutely anhydrous detergent used. Subsequently When the plate is placed in a vapor-free environment, e.g. in a absolutely dry air atmosphere, e.g. in an atmosphere of synthetic air, in a nitrogen atmosphere, helium atmosphere or a mixture of the corresponding gases to temperatures of about 150-200 ° C heated. At these temperatures, the monomolecular layer becomes water from the surface the quartz plate removed without affecting the internal properties to change the quartz structure.

Subsequently, will the quartz plate in its steam-free environment at room temperature, for example, at about 22 ° C, cooled. The cooled plate is in a gas-tight and water-free box or in a steam-free room stored so that it does not neoplasm of a monomolecular Water vapor layer comes on the surface.

Then must the surface calcium fluoride cement used in immersion lithography However, calcium fluoride crystals react substantially more sensitive to high temperatures and temperature changes than quartz crystals. For this reason, the optical element is in a vapor deposition system cleaned by internal fire.

After that is the optical calcium fluoride element according to the invention with a Adhesive layer, for example with a 30 to 50 nm thick quartz layer, practically steamed cold. After cooling the coated optical Elements is the steaming system with a dry gas or gas mixture, for example, with nitrogen, flooded. The optical element becomes subsequently placed in a steam-free environment, such as a dry box. In the best case, the steaming system is in a steam-free Environment, i. in a room with absolutely dry air, operated, so that the optical element when opening the steaming system if possible is not wetted with water vapor.

Then be the quartz plate and the coated surface of the calcium fluoride with their dry surfaces by a "dry" blasting together connected. In the cavities between the quartz layer applied to the optical element, optical element itself and in the connection area between the quartz plate and the optical element thus arise (except for unavoidable Impurities) do not contain water, which is the compound, in particular when shearing forces occur and UV laser irradiation, adversely affect.

The porosity the quartz layer ensures that still in the connection area as impurities existing water residues in the cavities the quartz layer are collected because of the tendency that trapped water in the cavities of the quartz layer a monomolecular water layer is formed.

Instead of an optical element made of calcium fluoride and / or a protective element made of quartz also other materials are used. For example, if that Potential of immersion liquids are fully utilized with high refractive indices are lenses helpful with high refractive index. One of the materials used with very high refractive index is LuAG.

One embodiment for the Dry bleaching with at least one body of LuAG refers on the production of projection objectives for microlithography. It a first lens is provided, which on the image side the penultimate curved represents optical element and on the image page, for example concave surface having. The first lens comprises a first intrinsically birefringent Crystal with a first orientation of the crystal axes. A second lens, which is the last curved optical element on the Represents an image page, has a corresponding to the object side convex surface and comprises a second intrinsically birefringent crystal. The crystal axes of the lenses are oriented so that an intrinsic Birefringence by the first crystal together with an intrinsic one Birefringence by the second crystal total to at least one nearly axisymmetric distribution of the total birefringence leads.

The Contact surfaces of the consecutively arranged crystals are not planar but curved, so that rays of light that travel through this interface, a total reflection even if they are from the first lens at very large angles with respect to the optical axis of the projection lens.

The Lenses become with their contact surfaces with the drying according to the invention Bleaching connected.

In addition, can in the system between the immersion liquid and the system the two lenses, at least one of which consists of LuAG, one Cover be provided. This cover plate can be attached to one of LuAG lenses are also fixed by means of a dry blasting. In particular, the protective plate itself may consist of LuAG.

One further application for this is the connection method according to the invention is the production of transmissive optical elements, which are composed of two sub-elements. These subelements are interconnected by an optical contact connection between their contact surfaces connected, the optical connection as seamless as possible transition should form. The first sub-element may, for example, be a planar convex lens, the second sub-element is a planar element, wherein the contact surfaces are planar are. The interface but it can also be a spherical one area be. Also, these surfaces must be before a dry blasting cleaned and freed of water molecules become.

At least one of the connected subelements can be present as spinel, in particular as polycrystalline spinel MgAl ₂ O ₄ or spinel ceramic. Polycrystalline magnesium spinel has differently oriented grains or crystallites with different crystal orientations. Using this material, a lens molding can be made directly in a spherical shape, for example by sintering followed by hot isostatic pressing. The value of the intrinsic birefringence is essentially 0 in all spatial directions. In this way, the intrinsic birefringence is suppressed. Consequently, arrangements for compensating intrinsic birefringence can be dispensed with.

One Disadvantage of the indicated method is that also on the edge the connection area between the lens and the quartz glass element through the porosity The vapor-deposited quartz layer is attracted to water and this in the cavities collects. Through diffusion, water vapor penetrates over time in the bonding layer between the lens and the quartz glass element one.

For this reason, in a particularly advantageous embodiment of the invention, which in the 2 is shown at the edge of the connection area 7 between a crystal lens 5 and a quartz plate 6 an example annular seal 8th intended. An annular cavity 9 can be grooved with a dry gas.

Around shear to be able to absorb at a temperature fluctuation, must also be the seal either elastic or as a monolithic joint in the components be self-trained.

Since in the said method according to the invention, the exposure takes place in a dry atmosphere, which is practically not achieved in conventional production spaces, are for the implementation of the "dry" Ansprengung based on 3 . 4 . 6 . 7 . 8th and 9 Proposed devices that can serve as a workplace for a "dry" Ansprengung.

The 3 illustrates a workplace 10 with two in a box 12 envisaged 11 for the hands and arms of a user. At her Surface shows the box 12 a UV-opaque glass layer 13 to observe the Ansprengvorgangs on. In the lower part of the box 12 is a hatch 14 provided for introducing the abutting optical elements.

Laterally in the interior of the box 12 extends a connection line 15 for supplying a dry gas into the interior of the box 12 , After a flush with a gas or gas mixture is the box 12 completely filled with an absolutely steam-free gas, such as helium, oxygen, etc. or a mixture. Since the filling gas is lighter than air in the present case, the gas remains within the box by itself 12 because through the hatch 14 possibly penetrating air can not rise into or over the lighter gas mixture.

In the 4 is the workplace 10 schematically sketched from above. Left and right are moorings 16a and 16b arranged on each of which one of the elements to be connected is stored. Near the moorings 16a and 16b is a drying agent 17 arranged. To the center in the direction of the Ansprengplatz 19 each is an anhydrous or hygroscopic cleaning bath 18a respectively. 18b (For example, acetone bath) provided.

In the central area of the workplace 10 is the Ansprengplatz 19 arranged. Lie on this, as in the 4 indicated, the two elements to be pressed against each other 1 and 2 , During wringing, the surfaces to be joined become the partners 1 and 2 approximated and under irradiation with a UV burner 20 brought brought into contact UV radiation. In this way, a "dry" brushing can be realized, allowing a safe and lasting connection between the elements 1 and 2 without significant water inclusions.

It It should be noted, however, that the jobs described above and below also otherwise, in particular for any other kind of "wet" blowing, used can be.

The Ansprengvorgang is detailed in the 5a to 5c outlined.

Once the elements 1 and 2 from their cleaning bath to the UV irradiation place or Ansprengplatz 19 Arrive, they are through the UV burner 20 initially irradiated vertically with UV radiation (cf. 5a ).

Subsequently, the parts 1 and 2 under continuous UV radiation facing each other, with the surfaces to be joined 1' respectively. 2 ' approach each other.

One Blasting paper can be inserted, removed and the blasting carried out become.

In the 5c is the composite of the elements 1 and 2 shown after the application. The composite body can now be removed from the flowbox 12 be removed.

Incidentally, instead of a strong UV irradiation, an ionized gas stream can also flow over the surfaces of the elements 1 and 2 Of course, the ionized gas stream must also be absolutely free of water.

The Operating personnel must carry out a "dry" blasting of optical Components with later expected temperature-related shear effects at any moment take special care to avoid the absence of moisture while to ensure the Aufengung. In addition to one possible low number of water molecules of course, too the presence of other impurities, for example the presence of dust particles, to be minimized.

In the 6 is the workplace 10 shown in a vertical sectional view. The previously described components of the workplace 10 are designated by corresponding reference numerals.

In particular, from the 6 clearly that one through the borderline 21 indicated upper portion of the interior of the box 12 is filled with an absolutely dry helium-oxygen mixture while in one below the interface 21 lying area of room air is present. The hatch 14 extends into the area of the interior of the box 12 below the interface 21 ,

To keep the helium-oxygen mixture completely dry during operation, a drying agent 17 , For example, P ₂ O ₅ , used. The water vapor pressure, which should not be higher than 5 × 10 ^-6 mbar at 22 ° C can be accommodated through the use of the desiccant to a value of for example 1 × 10 ^-6 mbar or less, since P ₂ O ₅ also the smallest traces remove from water vapor.

An alternative embodiment in a sectional view is shown in FIG 7 outlined. Already described components of the workplace 10 are designated by the same reference numerals.

The difference to the previously described embodiments is essentially that that instead of an inert gas that is lighter than air (for example, a helium-oxygen mixture), a shielding gas is used which is heavier than air and the lower portion of the interior of the box 12 below the interface 21 crowded. In the filled with the protective gas lower area are the components of the workplace already described 10 namely the moorings 16a and 16b , the cleaning baths 18a and 18b , the Ansprengplatz 19 , the UV source 20 and possibly drying agent for keeping the protective gas dry.

The protective gas is via an opening 22 that are in the lower part of the box 12 below the interface 21 extends, initiated before the Ansprengvorgang is initiated.

The embodiment offers the possibility of connecting the optical elements to be connected via one above the interface 21 located hatch in the interior of the box 12 bring in and from above on the moorings 16a respectively. 16b store. The process steps of the Ansprengvorgangs can essentially near the bottom of the box 12 be carried out from above.

The 8th shows a further ergonomically designed workplace according to the invention 10 in which the blowing-on process can be carried out while sitting. The box 12 is via a provided with a UV barrier, obliquely arranged observation window 23 visible. In this way, the steps performed by the user can be tracked. At the top, the box is through a UV-transparent SiO ₂ window 24 completed. A UV burner 20 is arranged in a space above the SiO ₂ window.

In the 9 is the workplace 10 of the 8th shown from the front. Frontal forward is the box 12 through the observation window 23 completed, up through the UV window 24 , In the side areas of the box 12 are obliquely forwardly provided, passage openings for the hands and arms of an operator. The grip of the hands is made with rubber gloves, which are at the edge of the openings 11 can be fastened so that between the outside of the rubber gloves and the edge of the openings 11 no moisture in the interior of the box 12 can penetrate.

• 1. Mechanisches Abreiben der Oberflächen, insbesondere der am Kristallelement vorgesehenen Verbindungsfläche. Diese Verbindungsfläche kann entsprechend einem der oben beschriebenen Verfahren eine bedampfte Fläche sein. Die Fläche ist gründlich zu reinigen, da auch Defekte der Aufdampfung entfernt werden müssen. Das mechanische Abreiben erfolgt beispielsweise durch Reiben der Oberfläche mit einem Mikrofasertuch.
• 2. Wasserfreies Reinigen von Hand oder in einem Ultraschallbad.
• 3. Als optionaler Schritt eine wasserentziehende Behandlung in schwacher H₃PO₄-Säure, beispielsweise in 5%iger H₃PO₄-Säure.

Another inventive method for "dry" Ansprengung is based on the 10a - 10c described. In the process, the parts to be pressed against each other 1 and 2 first pretreated appropriately before entering a vacuum ion beam chamber 25 be introduced. The pretreatment comprises the following steps:

• 1. Mechanical abrasion of the surfaces, in particular the connection surface provided on the crystal element. This bonding surface may be an evaporated surface according to any of the methods described above. The surface must be thoroughly cleaned, as defects of vapor deposition must also be removed. The mechanical abrasion takes place for example by rubbing the surface with a microfiber cloth.
• 2. Anhydrous cleaning by hand or in an ultrasonic bath.
• 3. As an optional step, a dehydrating treatment in weak H ₃ PO ₄ acid, for example in 5% H ₃ PO ₄ acid.

The pretreated, abut each other parts 1 and 2 with their largely water-free connection surfaces 1' and 2 ' are then placed in a vacuum recipient 25 introduced, in which an internal source 26 is arranged. In a vacuum, the surfaces become 1' and 2 ' cleaned, for example by bombardment with argon ions over a period of between 2 and 5 minutes (see. 10a ).

Subsequently, the parts to be pressed against each other 1 and 2 mechanically moving towards each other under continuous internal fire, as shown in the 10b indicated by arrows. The movement can be accomplished by a mechanical turning device.

The resulting from the Ansprengvorgang composite body of the parts 1 and 2 show the 10c ,

After the application, sealing should be carried out. The period between impacting and sealing should be as short as possible to allow diffusion of moisture over the edge of the contact surface between the parts 1 and 2 to largely prevent in the connection area.

For this purpose special storage methods and / or special storage facilities should be used. Effective is in any case a storage in a dry as possible, that is largely free of water molecules gas atmosphere. Also proves to be effective in a storage in a storage device (drying container) 27 , like in the 11 illustrated.

In the storage container, the composite member is made of a calcium fluoride (CaF ₂ ) lens 1 and a quartz glass plate 2 on a bracket 28 lying directly above a drying agent, such as a layer of P ₂ O ₅ , stored.

alternative it is also possible the composite body in a liquid to preserve their toughness is so big that the liquid not in the connection area between the optical element and the protective element creeps. Particularly advantageous is the use a liquid, which is strongly water attracting. In this case, a blow-up possibly even partially healed from the edge by being in the contact area between the optical element and the protective element attached thereto Stored water is withdrawn.

in the Below is another method for blasting an optical Elements described to a protective element for which protection is sought independently. The Blasting takes place at this. Procedure essentially in two Steps.

First, will a "wet" blowing of a Protective element to an optical element, such as a crystalline lens, carried out. This blasting is done in a conventional manner in a dust-free Room and / or in a flowbox.

In front the implementation of the "wet" blowing-up the blowing partners carefully cleaned them for to prepare the "wet" blowing-in. The items are freshly cleaned cotton towels and / or microfiber cloths abraded. At the same time, cleaning results in high transmission of the optical element for Light radiation, in particular for in lithography often used laser wavelengths 193 nm and 157 nm.

To rubbing off both partners, they are ready from residual dust, for example by means of a gas flow, or mechanically by means of a brush. The blasting is done by removing one always only once to be used Abziehvlieses. For Extreme requirements can be the Abziehvlies before analysis acetone getting cleaned.

It is self-evident that, under these conditions, water molecules are trapped between the preassembling agents after blasting, due to a monomolecular layer of water present on the surfaces of the reactants As in connection with the 1a and 1b described, the water molecules are included in the Ansprengvorgang between the contact surfaces.

Then be the parts in a transport box with a simple desiccant for Protection of the finished polished open (possibly already occupied) crystal lens kept.

In In a second process section, the transfer of the "wet" blasting into a "dry" bleaching takes place. This Process section is carried out in a possible water vapor-free atmosphere. For example For example, the method section may be one of those previously described Processing stations performed become. However, the process can also be in an already known conventional Manipulation chamber, which with dry gas, for example with Nitrogen, flooded and filled is carried out become. In addition to a breakthrough for hands with airtight rubber gloves to have such a known Manipulation chamber located on top of a glass insight on.

After introduction of the composite body with the still "wet" blasting into the dry chamber, the existing impingement is partially dissolved again 12a illustrated. By means of a micrometer screw 30a holding a plastic cap 31 has, is a local Teilabsprengung 1b . 2 B of the protective glass 2 from a crystal lens 1 generated. In the 12a is the still "wet" blasted area left with the reference numerals 1a . 2a , the detached area on the right with the reference numerals 1b . 2 B designated.

The wet-cracked area 2a and the dissolved area 2 B are in the 12b in a plan view of the plate 2 represented, wherein in the transition area of the dissolved area 2 B to the blown area 2a an area 2c recognizable with interference fringes. In the present case, more than half of the contact surface is blasted off again.

Subsequently, the monomolecular water layer in the gap between the lens 1 and the protective plate 2 , For example, by drying with nitrogen, optionally under UV irradiation removed. The gap between the component surfaces 1b . 2 B is dried.

After completing the drying process, the micrometer screw 30a turned back. The dried gap in the area 1b . 2 B will be closed again. By making a contact of the area 2 B of the protective element 2 with the contact surface 1b the lens 1 the contact surfaces are again collapsed, but this time "dry", ie without inclusion of water molecules (apart from remaining impurities).

A second micrometer screw 30b is then tightened to the previously "wet" sprinkled area 2a the protective plate 2 from the Lin se 1 to solve. The "wet" area is then also dried.

By the local and alternate detachment of a blasting and subsequent drying of the gap formed by the blasting, it is possible by simple manipulation to free the "wet" impingement of their monolayer water and in this way the "wet" impingement step by step over the entire area in one To convert "dry" bleaching, without at one time the quartz plate 2 completely from the lens 1 would be blown off.

An alternative way, a "wet" blowing a protective plate 2 to a crystal lens 1 into a "dry" erosion is based on the 13 clarified. Accordingly, the protective plate 2 from the crystal lens 1 completely blasted in a drying room. After the blasting, the plate is not raised, but held at a predetermined distance d, for example, at a small distance of d = 0.5 mm. The distance can, for example, by means of spacers 31 be set.

Subsequently, analogously to the previously described method, the water layer between the elements 1 and 2 by the flow of extremely dry gas, possibly with simultaneous UV irradiation from above, carried out. After the water molecules are largely removed from the intermediate space, the final, this time "dry" erosion takes place, ie an erosion of the contact surfaces of the lens 1 and the plate 2 to each other, without lying between the contact surfaces water molecules or water inclusions.

Of the essentially in two stages of the process has several advantages. For one thing, the preparation of the Surfaces, For example, cleaning by rubbing, in the free environment, and thus more easily than in a locked box. The necessary process, the surfaces ansprengfähig can be done in a much more favorable environment. Only the drying takes place in a practically anhydrous Bypass.

The In addition, two-stage methods point the advantage on that by the formation of only a narrow gap to remove the water by means of dry gas no dust in the Penetrate space and can contaminate this. In this way can nearly realized absolutely clean "dry" Ansprengungen become.

Claims (35)

A method of making a composite comprising the steps of: a) providing a first body ( 1 ) and a second body ( 2 ) each having a contact area provided for the connection ( 1' . 2 ' ); b) treating the contact surfaces ( 1' . 2 ' ) such that the contact surfaces of a monomolecular or multilayered layer of water molecules ( 3 ) are freed; and c) bringing together water molecules ( 3 ) freed contact surfaces ( 1' . 2 ' ) for wringing the first body ( 1 ) to the second body ( 2 ) for producing a composite body from the first body ( 1 ) and the second body ( 2 ). A method according to claim 1, characterized in that the first body comprises a crystal, in particular a calcium fluoride (CaF ₂ ) crystal. A method according to claim 1, characterized in that the first body comprises a lutetium aluminum garnet (LuAG, Lu ₃ Al ₅ O ₁₂ ) crystal. A method according to claim 1, characterized in that the first body comprises a material comprising spinel (MgAl ₂ O ₄ ), in particular polycrystalline spinel or spinel ceramic. Method according to claim 1, characterized in that that the first body Includes quartz glass. Method according to one of the preceding claims, characterized characterized in that the first body is an optical element. Method according to one of the preceding claims, characterized in that as the second body ( 2 ) a protective element, in particular a protective element comprising quartz, for the protection of the first body ( 1 ) is provided prior to contact with a liquid, in particular with water. Method according to one of the preceding claims, characterized in that the bringing together of the contact surfaces ( 1' . 2 ' ) of the first body ( 1 ) with the second body ( 2 ) is carried out in a vacuum. Method according to one of the preceding claims, characterized in that before the implementation of step c) at least one of the contact surfaces ( 1' . 2 ' ) of the first body ( 1 ) or the second body ( 2 ) at least over a portion of the contact surface ( 1' . 2 ' ) is provided with a coating. Method according to claim 9, characterized in that that the coating as a quartz layer, especially on the first Body, is applied. Method according to one of claims 9 or 109, characterized the coating has a thickness of 30 nm to 50 nm. Method according to one of claims 9 to 11, characterized that the coating by vapor deposition in a vacuum recipient on the body is applied. Method according to one of the preceding claims, characterized in that a seal ( 8th ) in the edge region of the contact surfaces ( 1' . 2 ' ) for sealing against the ingress of water molecules at the edge of the contact surfaces ( 1' . 2 ' ) in the connection area between the first body ( 1 ) and the second body ( 2 ) is arranged. Method according to one of the preceding claims, characterized characterized in that the step c) in an atmosphere of a inert gas or a gas mixture is carried out, which is substantially free of water molecules is. A method according to claim 14, characterized in that during the implementation of step c) at least temporarily UV radiation and / or an ionized gas stream on at least a portion of the contact surfaces ( 1' . 2 ' ) acts. Method according to one of claims 14 or 15, characterized in that in the atmosphere of the inert gas or gas mixture, a water-vapor pressure of less than 5 × 10 ^-6 , in particular less than 1 × 10 ^-6 , prevails. A method according to claim 1, characterized in that the method step c) in an evacuated recipient ( 25 ) under at least temporary bombardment of at least one area of the contact areas ( 1' . 2 ' ) of the first body ( 1 ) and / or the second body ( 2 ) is performed with ions. A method according to claim 17, characterized in that the bringing together of the contact surface ( 1' ) of the first body ( 1 ) with the contact surface ( 2 ' ) of the second body ( 2 ) is accomplished by means of a mechanical rotating device. A method of making a composite comprising the steps of: a. Providing a first body ( 1 ) and a second body ( 2 ) each having a contact area provided for the connection ( 1' . 2 ' ); b. Performing a wet blasting between the first contact surface ( 1' ) of the first body ( 1 ) and the second contact surface ( 2 ' ) of the second body ( 2 ) to form a composite body; c. Introducing the composite into a volume of a chamber containing an inert gas or gas mixture substantially free of water molecules; d. partial release of wet blasting in a first subregion ( 2 B ) of the contact surfaces ( 1' . 2 ' ); and e. Removing the between the contact surfaces ( 1' . 2 ' ) or at the contact surfaces ( 1' . 2 ' ) arranged water molecules ( 3 ). A method according to claim 19, characterized in that the erosion in step d) by actuation of a micrometer screw in an outer region on the first body ( 1 ) or the second body ( 2 ) attacks, is solved. Method according to one of claims 19 or 20, characterized in that the water molecules in step e) by the flow of a dry gas, in particular of nitrogen, through the intermediate space in the first part of the dissolved contact surfaces ( 1' . 2 ' ) are removed. Method according to one of claims 19 to 21, characterized in that after performing step e) step f. Reclaiming the dried contact surfaces ( 1' . 2 ' ) in the first subarea ( 1b . 2 B ) of the contact surfaces is performed. A method according to claim 22, characterized in that after the step f) the steps g) partial release of the Ansprengung over a second portion ( 1a . 2a ) of the contact surfaces ( 1' . 2 ' ); and h) distance between the contact surfaces ( 1' . 2 ' ) in the dissolved second subregion ( 1a . 2a ) or in the second subarea ( 1a . 2a ) contact surfaces ( 1' . 2 ' ) arranged water molecules. A method according to claim 23, characterized in that the steps g) and h) are repeated several times to water molecules and a water layer from the intermediate region between the contact surfaces ( 1' . 2 ' ) completely remove. A method of making a composite comprising the steps of: a) providing a first body ( 1 ) and a second body ( 2 ) each having a contact area provided for the connection ( 1' . 2 ' ); b) performing a wet blasting between the first contact surface ( 1' ) of the first body ( 1 ) and the second contact surface ( 2 ' ) of the second body ( 2 ) to form a composite body; c) introducing the composite into a volume of a chamber filled with an inert gas or gas mixed, which is essentially free of water molecules; d) complete detachment of the blasting over the entire contact area ( 1' . 2 ' ) between the first body ( 1 ) and the second body ( 2 ); and e) removing the between the contact surfaces ( 1' . 2 ' ) or at the contact surfaces ( 1' . 2 ' ) arranged water molecules ( 3 ). A method according to claim 25, characterized in that after step d), the distance (d) between the separated contact surfaces ( 1' . 2 ' ) is set. Method according to claim 26, characterized in that that a distance (d) between 0.25 mm and 0.75 mm, in particular of about 0.5 mm, is set. Method according to one of claims 26 or 27, characterized that the distance (d) is adjusted by means of at least one spacer. Method according to one of claims 25 to 28, characterized in that the water molecules in step e) by the passage of a dry gas, in particular by the flow of nitrogen, through the interspace of the contact surfaces ( 1' . 2 ' ) are removed. Method according to one of claims 25 to 29, characterized in that after step e) the step f) Wiederansprengung of the first body ( 1 ) on the second body ( 2 ) by contacting between the dried contact surfaces ( 1' . 2 ' ); is carried out. Impinging device ( 10 ) for carrying out a dry blasting, in particular for carrying out a dry blasting, in particular according to a method according to one of the preceding claims, comprising a cavity closed up / down with a flooding volume in the upper / lower region of the cavity, at least one impingement region arranged in the flooding volume (US Pat. 19 ) for wringing a first body ( 1 ) to a second body ( 2 ), and at least one supply line for supplying the flooding gas for filling the flooding volume. Impinging device according to claim 31, characterized in that the blowing device comprises a UV irradiator ( 20 ), which contacts the contact surfaces to be brought into contact during an exposure ( 1' . 2 ' ) at least temporarily irradiated before and during the Ansprengvorgangs. Composite body of a first body ( 1 ) and a second body ( 2 ), the first body ( 1 ) and the second body ( 2 ) are joined together, characterized in that the area of the contact surface ( 1' . 2 ' ) between the first body ( 1 ) and the second body ( 2 ) is substantially free of water molecules. Composite body according to claim 33, characterized in that between the first body ( 1 ) and the second body ( 2 ) a layer is arranged, the cavities for trapping in the contact area between the first body ( 1 ) and the second body ( 2 ), the contact area contaminating water molecules. Composite body according to one of claims 33 or 34, characterized in that in the edge region of the connecting surface between the first body ( 1 ) and the second body ( 2 ) is arranged a seal for sealing the connection region before the penetration of water molecules in the connection region.