AU2021373322A1

AU2021373322A1 - Hermetically connected arrangement, enclosure and method for the production thereof

Info

Publication number: AU2021373322A1
Application number: AU2021373322A
Authority: AU
Inventors: Stephan Corvers; Jens Herrmann; Bernd Hoppe; Clemens Kunisch; Antti Määttänen; Jens Ulrich Thomas
Original assignee: Schott AG; Schott Primoceler Oy
Current assignee: Schott AG; Schott Primoceler Oy
Priority date: 2020-11-08
Filing date: 2021-11-08
Publication date: 2023-06-22
Also published as: CN116420224A; JP2023547667A; WO2022096724A2; WO2022096724A3; EP4241301A2

Abstract

The invention discloses a hermetically connected arrangement comprising a first metallic substrate, a second substrate, at least certain regions of which and/or at least parts of which are designed to be transparent in respect of at least one wavelength range, wherein the first substrate is arranged with a contact surface adjacent to a contact surface of the second substrate, and also having at least one laser-joining line or a plurality of points of attachment for joining the first metallic substrate directly to the second substrate, on or in the contact surfaces, wherein the laser-joining line or the plurality of points of attachment, on the one hand, extends/extend into the first substrate and, on the other hand, extends/extend into the second substrate and fuses/fuse the at least two substrates directly to one another.

Description

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Verbffentlicht: mitinternationalemRecherchenbericht(Artiflcel2]Absatz 3) vorAblaufc/erfUrAnderungendewAnsprflchegeltenden Frist;VerifentlichungwirdwiederholtfallsAnderungen eingehen(Regel48Absatz2Buchstabeh) (88)Verbffentlichungsdatumdesinternationalen Recherchenberichts: 18~August2022(18~O8~2O22)

Hermetically connected arrangement, enclosure and method for the production thereof

Description

Field of the invention The present invention relates to a hermetically connected arrangement, to an enclosure, to a method for producing a hermetically sealed composite, and to the hermetically connected arrangement produced by the method.

Background and general description of the invention In principle, the joining together of multiple parts by means of different laser methods is known. For example, hermetically connected glass-glass transitions are known from the applicant's European patent document EP 3 012 059 B1. That document discloses a method for producing a transparent part for protecting an optical component. It presents an innovative laser method. Connections which involve the connection of different materials to one another are increasingly being scrutinized. Among these, the metal-glass transition is of special interest, since specifically the combination of metal and glass has a multiplicity of possible applications. For instance, improvements and new applications in the field of biophysics and technical medicine, in particular in terms of bioprocessors, and applications in aerospace can be practically realized. If a hermetically sealed enclosure is constructed, a component or components in the interior of the enclosure can be protected there from adverse environmental conditions. For instance, it is possible to arrange sensitive electronics, circuits or, for example, sensors in a hermetically sealed enclosure in order to construct and use, for example, medical implants, for example in the region of the heart, in the retina, or in general for bioprocessors. Fields of application can also be found for MEMS (micro-electro-mechanical systems), in sensor systems, such as for a barometer, a blood gas sensor or a glucose sensor etc., and also for electronics applications, such as in particular in the field of watch production or in general in the field of wearables and devices which, for example, are to have a water-protected or pressure-protected construction. It is also possible to find a wide variety of fields of use in aviation, in high temperature applications, in the context of electromobility, for example for the production of flow cells, and in the field of microoptics.

By contrast to a connection of two similar components to one another, the use of different materials presents the problem that the two parts to be joined adhere to one another poorly or actually must be made to bond. The object of the present invention is therefore to provide a hermetically connected arrangement between two components of different materials, wherein, in particular with metal, it was not possible to successfully realize this until now. Another object of the invention is also to provide enclosures, wherein two parts of different materials are to be connected to one another. In particular, a partial aspect of the present object is to be able to produce the hermetically connected arrangement or the enclosure in a sufficiently robust way, in order to ensure that the two parts do not detach from one another or already become detached from one another with a small action of force. Another partial aspect of the present invention is that possible material damage as a result of application of a joining method can be investigated and access can be provided for a check, and also that such possible damage should be avoided or reduced. A possible aim of the present invention is therefore to provide more reliable and more durable hermetically connected arrangements or enclosures. A hermetically connected arrangement according to the invention comprises a first metal substrate and a second substrate, which is formed as transparent to at least one wavelength range at least in certain regions and/or at least partially. The first substrate, by way of a contact area, is arranged adjacent to a contact area of the second substrate. Within the meaning of this application, a contact area is a region or a part of a surface, or an entire side of the respective substrate, by way of which the respective substrate comes to lie or is arranged adjacent to the respective other substrate. Typically, the substrates are arranged next to one another or one on the other. When the two substrates touch one another directly and immediately, a touching-contact area is formed. The touching-contact surface is thus, for example, a sub-area of the contact area at which the distance between the two substrates is so small that it can no longer be measured visually.

The at least two substrates are typically first of all arranged one on another, that is for example stacked one on another, to connect them. The gravitational force can then cause the upper, typically second substrate to be pressed against the lower, typically first metal substrate. The orientation - above or below - in this case is merely descriptive, since of course the arrangement of the substrates can assume any orientation in space and even an arrangement next to one another is not outside the scope of protection. The two substrates are typically arranged lying against one another by way of a larger side of their extent. For example, the two substrates have a pane-shaped or flat form and therefore each have at least one larger flat side, which is preferably aligned in the direction of the respective other substrate. The hermetically connected arrangement also comprises at least one laser joining line or a plurality of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas. The laserjoining line or the plurality of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another. In other words, the two substrates are joined to one another in the laser joining line. The respective substrate has a planar form in the contact areas. In this respect, an absolutely planar surface is only theoretically achievable, since, depending on the scale under consideration, depressions, elevations or curvatures or all of these can be found even in the case of polished surfaces. Touching contact over the entire surface area is therefore difficult to establish. Instead, substrates, even if only to a very small extent, are domed, inclined, curved, or provided with depressions or elevations. For example, a touching-contact area can be defined when there is a mean distance between the first substrate and the second substrate of less than or equal to 1 p m, preferably less than or equal to 0.5 p m, and more preferably less than or equal to 0.2 p m. Within the scope of the present invention, it has proven to be advantageous here if the distance between the first substrate and the second substrate is smaller. For instance, it is advantageous if the surface in the contact area of the first substrate and/or the surface in the contact area of the second substrate are polished before the substrates are arranged one on the other, in order to further reduce the mean distance between the substrates. In the case of the first metal substrate, it can be advantageous when absolute elevations above a mean surface of the metal substrate do not exceed 0.5 p m. This is surprising, therefore, because a polished surface of the metal substrate in principle is disadvantageous for a laser joining method, since on a polished surface more reflections occur and therefore the exact positioning and power deposition for the joining operation is made more difficult or the joining operation possibly thus cannot be carried out. However, specifically with polished contact areas of the metal first substrate, it was possible to produce good connected arrangements that adhere to one another strongly.

A mixing zone, in which material of the second substrate and material of the first substrate are merged, is present in the laser joining line or the plurality of binding points. In the mixing zone, metal material of the first substrate can have entered the second substrate. In the mixing zone, material of the second substrate can also have entered the first metal substrate. Particularly preferably, it is possible for both metal material of the first substrate to have entered the second substrate and material of the second substrate to have entered the metal substrate in the mixing zone. The mixing zone can have a thickness measured in a direction perpendicular to the contact areas, wherein the thickness of the mixing zone can have a thickness of preferably at least 1 p m, more preferably 2 p m or more, more preferably 5 p m or more. The mixing zone preferably extends 1 p m or more into the second substrate. Preferably, the mixing zone extends 5 p m into the second substrate. More preferably, the mixing zone extends as far into the second substrate as the resolidified zone does, with the result that the mixing zone is superposed on the resolidified zone. For example, the mixing zone extends approximately as far into the second substrate as it does into the first substrate. This is surprising at first glance, since, for example, in the case of a metal-glass composite the CTE of the first substrate is 3 to 10 times higher than the CTE of a glass. The heat capacity and heat conductivity of the metal are typically considerably higher than those of the second substrate. However, it has been shown that it is possible to set the mixing zone advantageously in the laser joining line or the binding points such that it extends approximately as far into the first substrate as it does into the second substrate, and thus improves the joined connection. The mixing zone has a width, wherein the width of the mixing zone is preferably greater than the thickness of the mixing zone in the second substrate. The width of the mixing zone may also be greater than the thickness of the mixing zone by 50% or more, more preferably is greater than the thickness of the mixing zone by 100% or more. In this respect, the width of the mixing zone may, for example, be measured at the contact area between the first and the second substrate and in a direction parallel to the contact area and perpendicular to the laser joining line. The at least one laserjoining line or the plurality of binding points may also comprise a resolidified zone, wherein the resolidified zone has a thickness measured in the direction perpendicular to the contact areas. The thickness of the resolidified zone can preferably be less than or equal to 20 p m, preferably less than or equal to 10 p m, and more preferably less than or equal to 5 p m.

The resolidified zone may also extend less than or equal to 20 p m, preferably less than or equal to 10 p m, and even more preferably less than or equal to 5 p m, into the depth of the second substrate. The resolidified zone of the at least one laser joining line or the plurality of binding points can extend along the laser joining line or be arranged in the respective binding points. The resolidified zone may have a width of 10 p m, for example +/- 5 p m, at the contact area between the first and the second substrate and in a direction parallel to the contact area. This width can preferably be 20 p m +/- 10 p m, more preferably 30 p m +/- 10 p m. The resolidified zone can also have a width, in a direction parallel to the contact area and perpendicular to the laser joining line, that is larger than the thickness of the resolidified zone. The resolidified zone is particularly advantageously as small as possible, that is to say the parameters of the irradiation by means of the joining laser can be selected such that the resolidified zone is as small as possible. The resolidified zone is not useful for the joining operation, since there no material is blended such that serrated engagement or adhesion between the first substrate and the second substrate is produced. The resolidified zone thus absorbs laser energy without the aim of improving the adhesion. At the same time, cracks and/or holes or cavities are produced in the resolidified zone when the latter is being cooled down, which can possibly be explained in that the material of the respective substrate expands when it is being heated, generates stresses as a result, and contracts again when it is being cooled down. The mixing zone is also set to be as large as possible, whereas the resolidified zone is set to be as small as possible. Preferably, the mixing zone has a height of at least 1/5 the height of the resolidified zone, more preferably % the height of the resolidified zone, more preferably the mixing zone is as high as the resolidified zone. For example, in this respect, given a height of the mixing zone of 5 p m, the height of the resolidified zone above the mixing zone is 25 p m, if the height of the mixing zone is 1/5 the height of the resolidified zone. If the height of the mixing zone is 10 p m, and above this the height of the resolidified zone of the second substrate is likewise 10 p m, the height of the resolidified zone corresponds to the height of the mixing zone. The mixing zone may also have a larger thickness than the resolidified zone, for example 1.5 times as thick or more, for example 5 times as thick, as the resolidified zone. The first metal substrate also typically has a resolidified zone underneath the mixing zone. Up to now, it was not possible to assert that the size of the resolidified zone of the first substrate is disadvantageous for the joining operation, as in the case of the second substrate. By contrast, it was possible to show that material of the second substrate can penetrate the resolidified zone of the first substrate and there can cause dendrite formation, that is to say an anchoring connection of the second substrate on the first substrate via one or more dendrites can be effected, wherein the dendrites can extend into the resolidified zone of the first substrate. In the mixing zone, material of the first substrate and material of the second substrate may be arranged in such a way that a form-fitting serrated engagement between the material of the first substrate and the material of the second substrate is brought about. The hermetically connected arrangement may comprise a fused-together serrated structure between the first metal substrate and the second substrate. In the fused-together serrated structure, it is possible for material of the respective other substrate to be pushed out, pushed in or undercut, so that, as a result, the adhesive bond of the hermetically connected arrangement is considerably strengthened. Such a fused-together serrated structure provides a form-fitting bond between the two substrates, this in particular being advantageous when the material bond between different materials can provide possibly only a small holding force or a weak material bond. The serrated structure between the first and the second substrate acts like a microscopic zip fastener. In the mixing zone, metal material of the metal substrate can be present in the form of droplets and/or dendrites, wherein the arrangement in the form of droplets and/or dendrites causes consolidation of the bond between the first and the second substrate. More noteworthy is the fact that metal material of the metal substrate and/or material of the second substrate can have also penetrated at least one of the resolidification zones, in particular in the form of droplets, melted portions and/or dendrites, and causes consolidation of the bond between the first and the second substrate. In other words, the parts to be joined, i.e. the material of the first substrate and/or the material of the second substrate, are selected and/or the beam generator is set and/or aligned to adjust the joining process in such a way that metal material of the metal substrate and/or material of the second substrate penetrates the resolidification zone assigned to the respective other substrate. For example, material of the first and/or second substrate can have an amorphous region or zone as a result of or after introduction of the laser joining line. Such an amorphous region, that is to say for example amorphous metal material, can further improve the serrated engagement. The contact area of the first substrate may have at least one touching-contact region in which the first substrate is in extensive touching contact with the second substrate. The touching contact area may in particular have a mean distance between the first and the second substrate of less than or equal to 1 p m, preferably less than or equal to 0.5 p m, and more preferably less than or equal to 0.2 p m. In this case, for technical reasons or other reasons, it is possible, for example, that very small gas pockets or impurities, such as dust particles or unevennesses from a polishing operation, between the substrate layers cannot be avoided. This can also result from possible unevennesses even into the microregion between the substrate layers or on the surfaces of the substrate layers. The touching-contact area can correspond to the contact area, when it is possible to establish contact between the two substrates over their entire surface area. The laser joining line can connect the first substrate to the second substrate such that the two substrates can be separated from one another only by applying a holding force. The join between the two substrates can also be obtained to such a strong extent that separating the two substrates from one another can be achieved only by destroying the second substrate if the holding force is greater than the force necessary to destroy the second substrate. The holding force of the second substrate on the first substrate may, for example, be greater than 10 N/mm 2

, preferably greater than 25 N/mm 2, more preferably greater than 50 N/mm 2, even more preferably greater than 75 N/mm 2 and ultimately most preferably is greater than 100 N/mm 2

. The first substrate may be characterized in that the contact side has a flat form, that is to say in particular planar form. The contact side of the first substrate may be polished. The contact side of the first substrate may in this case have a mean roughness Ra of less than or equal to 0.5 p m, preferably less than or equal to 0.2 p m, more preferably less than or equal to 0.1 p m, even more preferably less than or equal to 50 nm and ultimately preferably less than or equal to 20 nm. The second substrate may be characterized in that it has a flat form, in particular planar form, at the contact area, and more particularly has a mean roughness Ra of less than or equal to 0.5 p m. The laser joining line is introduced by means of a joining laser. For example, the joining laser has a wavelength of preferably 1030 nm, if it is an infrared laser. An ultrashort pulse laser with pulse lengths in the range of 50 ps or less, preferably 20 ps or less, more preferably 10 ps or more preferably 1 ps or less, may for example be used. The joining laser has a beam focus. The beam focus may have a beam waist width 2w0. For the joining process, the joining laser also has a beam width2 WLaser that can be greater than or equal to the beam waist width 2w0. The focal plane for the introduction of the laser joining line may be displaced distally relative to the joining plane. The beam width2WLaser is in particular in that case greater than the beam waist width 2w0, if the focal plane for the introduction of the laser joining line is distally displaced. In particular, the focal plane is in the first substrate when the laser joining line is being introduced. The focal plane is displaced preferably 10 p m ±10 p m, more preferably 20 p m ±10 p m, distally into the first substrate. The beam width 2WLaser is preferably 4 p m ±1 p m, more preferably 4 p m ± 2 p m, more preferably 4 p m ±3 p m, in the joining plane. This can be achieved for example when the focal plane is in the first substrate when the laser joining line is being introduced, that is to say for example is displaced 10 p m +/- 10 p m or 20 p m +/- 10 p m distally into the first substrate. As an alternative or in addition, the laser beam may widen or narrow upstream of the inscription lens, for example as a result of an aperture or a telescope, in order to set the beam width2 WLaser to the desired width. The first substrate preferably consists completely of metal material. In this case, the first substrate comprises metal within the meaning of the definition of the Periodic Table of the Elements. The first substrate may comprise or consist of at least one of molybdenum, tungsten, silicon, platinum, silver or gold. The first substrate may also comprise an alloy. In particular, the first substrate may comprise at least one of carbon, copper, manganese, chromium, magnesium, cobalt, nickel, tin, zinc, niobium, palladium, rhenium, indium, tantalum, titanium or iridium. The second substrate is preferably a transparent substrate. The second substrate may comprise or consist of glass, glass-ceramic, silicon, sapphire or a combination of the aforementioned materials. The second substrate may also comprise or consist of ceramic material, in particular oxide-ceramic material. The second substrate may comprise or consist of at least one of quartz glass, borosilicate glass, aluminosilicate glass, a glass-ceramic such as Zerodur, Ceran or Robax, an optical ceramic such as aluminum oxide, spinel, pyrochlore or aluminum oxynitrite, calcium fluoride crystal or chalcogenide glass. In a refinement or an alternative configuration, the hermetically connected arrangement may comprise the first metal substrate and the second substrate, which is formed as transparent to at least one wavelength range at least in certain regions and/or at least partially. In this case, the first substrate, by way of the contact area, is arranged adjacent to the contact area of the second substrate. The hermetically connected arrangement also comprises at least one spacer for establishing a distance between the first and the second substrate. The spacer may be inserted or comprised between the first metal substrate and the second substrate. For example, the first substrate may in that case be in contact with the second substrate via the spacer. In other words, the spacer may be arranged, for example, in certain regions on one of the contact areas, with the result that the respective other substrate comes into contact or touching contact with the spacer but a distance, for example of the magnitude of the thickness of the spacer, remains between the contact area of the first substrate and the contact area of the second substrate outside the spacer. The first substrate may thus be in contact or in touching contact with the second substrate via the spacer. The spacer may accordingly be arranged between the first substrate and the second substrate. The spacer may consist of metal material. For example, the spacer may be in the form of a coating on the first or the second substrate. The spacer may also be formed in one piece with the first substrate. The spacer may be formed in one piece with the surface of the first substrate and/or of the second substrate and thus, for example, form an offset or an elevation there. For example, the spacer can be produced in the course of polishing, if regions of the contact area of the first substrate or of the second substrate are not polished and thus elevations remain there. Specifically in the case of sapphire as second substrate, such as in particular in the form of a timepiece glass, in the case of which typically complex polishing of the sapphire glass has already taken place, additional or modified polishing of the sapphire glass can be conjointly carried out during the polishing step, so that no additional work step is required for the production. The spacer may be produced as a thin film, for example of aluminum, which can be affixed to the first or second substrate. The spacer may be sputtered on. The spacer may comprise a directly deposited Litho-glass layer. The spacer may also be printed on the first or the second substrate, for example by the inkjet printing method. The spacer may also be produced by means of 3D printing. The spacer may extend at least along the laser joining line or in the region of the binding points. The spacer may extend outside the laser joining line or outside the region of the binding points. The spacer may also be formed over the entire surface area. In one example, the spacer is formed in that, in its contact area, the first metal substrate is polished, but is not polished so as to be completely planar; rather, a spacer, which is for example web-shaped, remains in the contact area of the first substrate. This spacer is thus formed in one piece with the first substrate and as an elevation from the contact area of the first substrate. The spacer can preferably be arranged where the laser joining line(s) is/are introduced. This can further reduce the distance remaining between the substrates in the region of the laser joining line(s) and/or improve the joining result or the adhesion of the two substrates to one another. The spacer may have a thickness of at least 5 p m, more preferably a thickness of at least 10 p m, and even more preferably a thickness of at least 20 p m. This is advantageous especially when the spacer is inserted in the region of the laser joining line. If the spacer is not inserted in the region of the laser joining line(s) to be placed, but for example adjacent thereto, it is advantageous if the spacer does not exceed a thickness of 5 p m. For example, the spacer may have a thickness of preferably greater than 1 p m, preferably 2 to 3 p m or more. Within the context of the invention, also disclosed is a hermetically connected arrangement comprising a first metal substrate, a second substrate, which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area, is arranged adjacent to a contact area of the second substrate, and having at least one flow zone for receiving molten material from a laser joining line or a binding point, wherein the laser joining line or a plurality of binding points is used for directly meltingly joining the first metal substrate to the second substrate. In this respect, the at least one flow zone is preferably arranged adjacent to the laser joining line or the plurality of binding points. In other words, the flow zone is arranged such that molten material can flow into the flow zone, in particular at the moment the laser joining line is generated. For example, the flow zone can be arranged around the laser joining line and thus in communication therewith, with the result that material heated to a molten state in the laser joining line can flow into the flow zone slightly. In the process, the molten material can follow a pressure gradient during the flow operation. For example, when introducing the laser joining line of the first substrate and/or of the second substrate, expansion, for example thermal expansion, can be exhibited. Since the laser only locally heats material, that is to say material remains in the solid state around the laser joining line, great stresses can possibly arise between the material of the laser joining line and the material surrounding the laser joining line and can give rise to cracks, such as stress cracks, or cavities. By providing the flow zone, molten material can flow into the flow zone, with the result that the production of cracks or cavities is reduced. The at least one flow zone, or else buffer zone or relaxation zone, is more preferably arranged between the first and the second substrate, for example at the contact area there.

The at least one flow zone may, for example, be formed at the contact area when the second substrate is being arranged on the first substrate, when, for example, one of the two substrates or both substrates do not have a planar surface in the region of the contact area or on the side facing toward the respective other substrate. Particularly preferably, the flow zone is formed in that a spacer is comprised, which allows the two contact areas to come to lie on one another at a defined distance from one another, when the second substrate is arranged on the first substrate. The cavities that form in the process between the first and the second substrate in the regions in which there is no spacer can be configured or arranged beforehand such that they can be used as flow zone for material flowing out during the laser joining operation. As a result, the laser joining line produced becomes subject to less stress and thereby possibly provides a stronger or higher adhesive force, wherein at the same time stresses can be kept out of the second substrate, that is to say form less stress cracks or cavities in the second substrate. If the zone in which molten material of the two substrates is mixed together is designated as the mixing zone, and the zones that are adjacent thereto of the laser joining line are designated as resolidification zones, specifically the resolidification zones are then problematic in terms of cracks or cavities possibly arising there as a result of the introduction of the laser joining line. This is particularly disadvantageous when the second substrate is, for example, a single crystal such as a sapphire, in which damage caused by introducing a laser joining line cannot be repaired by the later introduction of a non-congruent, subsequent laser joining line. The present ideas, in particular the flow zone and/or the spacer, therefore make it possible to keep the resolidification zone as small as possible, but at the same time to allow the mixing zone to be as large as possible or to extend into the two substrates to the greatest possible extent. In the ideal case, the mixing zone is as large as the resolidification zone, such that the mixing zone is thus completely superposed on the resolidification zone and no resolidification zone as such remains perceptible. In that case, the adhesion of the two substrates to one another is particularly good, but at the same time the production of cracks or cavities is minimized. A hermetically connected arrangement comprises a first metal substrate, a second substrate, which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area, is arranged adjacent to a contact area of the second substrate, a first laser joining line or a first set of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas, wherein the first laser joining line or the first set of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another, and a second laser joining line or a second set of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas, wherein the second laser joining line or the second set of binding points extends into the first laser joining line or the first set of binding points and modifies or improves the mixing of material achieved by the first laser joining line or the first set of binding points. Such a second laser joining line can be achieved by resetting the same laser to a previous joining position or a joining position similar thereto, that is to say the new laser focus overlaps with an already set or already initiated focus point. The introduction of a second laser joining line, in particular into the still-warm or -hot first laser joining line, can also be generated by using a double focus on the laser generator. For example, a beam splitter or a diffraction grating, or else two laser generators, can be used for this. In this case, the second laser joining line is introduced into still-warm, in particular still-molten material of the first and the second substrate. Such an effect, that is to say the introduction of laser energy into still-warm or even still molten material, can also be created, for example, when the laser generator has a burst function, and in this way an overlapping plurality of laser points can be introduced into the arrangement in a short time sequence. In other words, another focus point can be initiated or a second laser joining line can be introduced at a focus point of the first laser joining line with a defined time interval and/or at a defined spatial distance. Within the context of the invention, also disclosed is a hermetically sealed enclosure, in particular having a hermetically connected arrangement as previously already described in detail. The hermetically sealed enclosure comprises a metal first substrate, a second substrate, which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area, is arranged adjacent to a contact area of the second substrate. The enclosure also comprises at least one functional region, in particular a cavity, arranged between the first and the second substrate, The enclosure also comprises at least one laser joining line or a plurality of binding points for directly and immediately joining the first substrate to the second substrate, on or in the contact areas, in particular around the functional region to hermetically seal off the functional region. In this respect, the laser joining line or the plurality of binding points extends for the one part into the first substrate and for the other part into the second substrate and the at least two substrates are directly meltingly joined to one another by means of the laser joining line or the plurality of binding points. In the hermetically sealed enclosure, the laser bond line of the enclosure may be formed all the way around the functional region so as to seal it. In addition or as an alternative, a distance between the first substrate and the second substrate in the laser bond line is continuously less than 0.75 p m, preferably less than 0.5 p m, and more preferably less than 0.2 p m. The functional region of the enclosure may have a hermetically sealed accommodation cavity for receiving an object to be accommodated, such as an electronic circuit, a sensor or MEMS. The hermetically connected arrangement or hermetically sealed enclosure may also have a first covering or coating on the metal first substrate at least in the region of the laser joining line or the plurality of binding points on a side facing toward the second substrate. The laser joining line or the plurality of binding points is in particular provided for directly and immediately joining the first metal substrate to the second substrate. In this case, the first covering or coating on the metal first substrate may preferably be applied before the hermetically tight connection of the at least two substrates to one another by directly joining the at least two substrates. In the case of the hermetically connected arrangement or hermetically sealed enclosure, it is also possible for material of the first substrate and material of the first covering or coating to be mixed in in the mixing zone and/or at least in a region of the first substrate that is close to the surface. In the case of the hermetically connected arrangement or hermetically sealed enclosure, it is furthermore in particular possible for the morphology of the microstructure in the mixing zone to be modified by the material of the first covering or coating. In the mixing zone, an alloy which at least comprises material of the metal first substrate and the first covering or coating can be formed at least in certain regions. The alloy mentioned above may preferably form a eutectic. The metal first substrate of the hermetically connected arrangement or of the hermetically sealed enclosure may also comprise or consist of iron, steel or an iron-containing alloy. The first covering or coating may also comprise carbon or consist of carbon. In the case of the hermetically connected arrangement or hermetically sealed enclosure, it is also possible for the mixed-in material of the first covering or coating to bring about consolidation of the bond between the first and the second substrate.

In the case of the hermetically connected arrangement or hermetically sealed enclosure it is also possible, in particular before the hermetically tight connection of the at least two substrates to one another by directly joining the at least two substrates, for a second covering or coating to be arranged on the second substrate at least in the region of the laser joining line or the plurality of binding points on a side facing toward the first substrate, in particular to directly and immediately join the first metal substrate to the second substrate. The first or the second covering or coating, as described above, on the second substrate may comprise or consist of a composition by means of which it is possible to develop a compressive stress within the second substrate in a zone of the second substrate which is close to the surface and extends perpendicularly in relation to the surface of the second substrate, at least to a depth DoL. Material of the second substrate and material of the second covering or coating can be mixed in or introduced in the mixing zone and/or at least in a region of the second substrate which is close to the surface. The second substrate of the hermetically connected arrangement or hermetically sealed enclosure may furthermore comprise or consist of a material in which at least compressive stresses close to the surface can be introduced in a compressive stress zone Ds and the first covering or coating comprises or consists of a material which makes it possible to introduce compressive stresses into the material of the second substrate in particular by ion exchange. In this respect, the material of the second substrate may comprise or consist of a glass, in particular a soda-lime silicate glass or borosilicate glass. The material of the second covering or coating may also comprise a compound which is suitable for giving up exchangeable ions, in particular a sodium and/or lithium compound, in particular sodium nitrate and/or lithium nitrate. The mixed-in or introduced material of the second covering or coating makes it possible to bring about consolidation of the bond between the first and the second substrate. Also within the scope of the invention is a method for producing a hermetically sealed assembly of at least two parts, said method having the following steps: extensively arranging at least one first metal substrate on a second substrate, wherein the at least two substrates are arranged on one another, with the result that a contact area, in which the first substrate is in contact with the second substrate, is formed between the at least two substrates, and wherein the second substrate comprises a transparent material. The method also comprises connecting the at least two substrates to one another in a hermetically tight manner by directly joining the at least two substrates to one another in the region of the at least one contact area, resulting in the formation of a mixing zone, which extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another. In the course of this method, a first covering or coating may be arranged on the first substrate before the at least one first metal substrate is extensively arranged on the second substrate. It is also advantageously possible to arrange a second covering or coating on the second substrate before the at least one first metal substrate is extensively arranged on the second substrate. In this respect, the designation first covering or coating and second covering or coating is not limitingly restricted to two coverings or coatings. Within the scope of the present disclosure, the respective embodiments may also comprise either only a first covering or coating or a second covering or coating. A contact area can be construed as a plane of the mutually inclined faces of the two substrates to be brought into contact. The touching-contact surface means a sub-area of the contact area at which the distance between the two substrates is so small that it can no longer be measured visually. Lastly, within the context of the present invention, a good area is defined in which the distance between the substrates is sufficiently small, as will be described in detail below, or else the two substrates actually touch. In general, in this respect, the contact area is greater than or equal to the good area and the good area in turn is greater than or equal to the touching-contact area. Both the first substrate and the second substrate may each have at least one contact area. The contact area can also be construed as the plane in which there is contact between the first and the second substrate. In other words, first of all two substrates are arranged one on the other, that is to say, for example, stacked one on the other, wherein the gravitational force presses the upper, typically first substrate against the second substrate. The orientation - above or below - in this case is meant merely descriptively, since of course the substrates can assume any orientation in space and even an arrangement next to one another is not intended to be outside the scope of protection. The two substrates are typically arranged lying against one another by way of a larger side of their extent. If the two substrates have an absolutely planar form, that is to say have no depressions, elevations or curvatures at all, something which in this absoluteless is achievable only theoretically, then the first and the second substrate would be in touching contact with one another over their entire surface area. The two substrates would therefore touch one another at all points of the mutually facing surfaces. In general and in the constructional reality, this is not something which can be achieved. Instead, substrates, even if only to a very small extent, are nevertheless domed, inclined, curved, or provided with depressions or elevations, and so complete touching contact is achieved only in absolute exceptional cases if at all. In this respect, touching-contact areas in which the substrates touch one another, or in which the distance between the substrates is smaller than a certain extent (e.g. defined as "good area", as will be explained below), form. If the substrates are arranged directly one on the other, this means that the at least two substrates are arranged one on the other or applied to one another such that they come to lie on one another over their entire surface area, in particular without other materials or layers being present or inserted between the at least two substrates. Possibly, for technical reasons, very small gas pockets or impurities, such as dust particles, between the substrate layers cannot be avoided. This can also result from possible unevennesses even in the microregion between the substrate layers or on the surfaces of the substrate layers. If the joining zone or laser bond line generated by the laser preferably, for example, provides a height HL of between 4-25 p m, a hermetic seal can be ensured by means of the laser bond line, since the distance that possibly arises between the two substrates can be bridged. One of the laser bond lines, or the laser bond line may enclose the functional region all around at a distance DF. The distance DF all around the functional region may be constant, with the result that the laser bond line is arranged at approximately the same distance around the functional region on all sides. Depending on the use case, the distance DF may also vary, this possibly being more favorable in terms of production if, for example, a plurality of enclosures is joined in a common work step, or if the functional region has a round or arbitrary shape and the laser bond line is drawn in a straight line. Even if the cavity has optical properties, for example is shaped in the form of a lens, such as an axicon, the laser bond line may be formed around the cavity and possibly have different distances from the cavity. An enclosure may also comprise multiple cavities. The method may also comprise the following step: checking the hermetic assembly of the at least two substrates by ascertaining a distance profile between the at least two substrates. It may also comprise the following step: ascertaining a first bond quality index Q1 for checking the mechanical strength or the hermetic nature of the assembly.

The first bond quality index Q1 may be ascertained by Q1 = 1 - (A - G)/A. In this case, A represents the area of the contact area and G represents a good area. The good area G corresponds in particular to the touching-contact area; the good area G may describe a part of the contact area in which the distance between the substrates is less than 5 p m, preferably less than 1 p m and more preferably less than 0.5 p m, lastly and most preferably less than 0.2 p m. The bond quality index Q1 may be greater than or equal to 0.8, preferably greater than or equal to 0.9 and more preferably greater than or equal to 0.95. The contact area may have a useful region N, and the useful region can be used to calculate the first bond quality index Q1. Q1 is then ascertained by Q1 = 1 - (N - G)/N. Within the context of the method, a radiative reflection which comes about through the irradiation of the substrate stack with a radiative input in at least one contact area of the substrate stack can be detected for this. In other words, the substrate stack is irradiated or illuminated, and consequently at the surfaces of the substrates a radiative reflection is generated from the radiative input. This radiative reflection may be the reflected radiative input, which is reflected to a certain extent at one of the surfaces. In the case of two substrates, wherein the first substrate is metallic, three surfaces at which such reflection can already take place may be relevant for this purpose. These are the top side of the first metal substrate, the inner side of the second, in particular transparent substrate, and the outer side of the second substrate. In other words, the first substrate has an outer side or else outer flat side which is aligned toward the surroundings and which has a substantially planar or flat form. An all-round narrow side borders the outer flat side, is oriented typically at right angles to the outer flat side, and is configured, for example, to run all around the margin of the outer flat side. In one example, the first substrate can be described as a plate or block, having two large-area sides (i.e., the outer side and the inner side) and also four smaller sides arranged between the large-area sides, these smaller sides being, in particular, perpendicular to the two large-area sides and bordering the large-area sides. In that case, the four smaller sides together form the all-round narrow side, and the top side forms the outer flat side of the first substrate. This top side typically has a greater surface area than the smaller sides of the all-round narrow side together. These statements relating to sizes and proportions may also be valid analogously for the second substrate. In a region in which the two substrates are in touching contact, there is no reflection, or no notable reflection, at the inner sides of the two substrates, and so this fraction is comparatively small. If, however, the two substrates come apart, and there is therefore a distance between the two substrates, with the two substrates in this partial region thus not being in touching contact, then the radiative input is reflected to a certain fraction in each case at all three surfaces of the two substrates. In the case of more substrates, such as three substrates, for example, it is possible correspondingly to take more surfaces into account. From the radiative reflection which is incident from the substrate stack into a measurement or observation device, a first bond quality index Q, of the contact area of the substrate stack is ascertained. For example, the first bond quality index Q1 is ascertained before the first and the second substrate are joined to one another. The method may also comprise the following step: ascertaining a second bond quality index Q2 of the contact area of the hermetically tightly joined assembly, wherein in particular Q2 is greater than Q1. More particularly, Q2/Q1 is greater than 1.001. The radiative reflection preferably generates a pattern, in particular an interference pattern, and, more particularly, this pattern is generated from the superimposition of the radiative input with the backscatter in the at least one contact area of the enclosure. In that case, it is possible to configure the measurement or observation device such that it recognizes or detects the interference pattern and is able from it to calculate or deduce the distance between the two substrates. The pattern from the radiative reflection may have an arrangement in which the pattern extends around one or more defects. In other words, the pattern may be arranged particularly around those places in which the at least two substrates are not in touching contact. In that case it is particularly straightforward to use the measurement or observation device to locate the places at which the at least two substrates are not in touching contact. A defect here may be characterized in that the distance between the substrates at these defects is greater than 5 pm, preferably greater than 2 pm and more preferably greater than 1 pm, greater than 0.5 pm, or else preferably greater than 0.2 pm. In other words, a defect is located with particular preference at exactly the point where the criteria for a good area G are not satisfied. In this case, the contact area between the at least two substrates may be completely divided into good area G and defect F. The corresponding regional assignment may be identifiable, in one example, from an interference pattern in the form of Newton's rings. If the radiative input is set in the range of visible light, for example with A = 500 nm, each Newton ring exhibits a height difference ofA/2= 250 nm. If, for example, the occurrence of three Newton rings is set as the boundary criterion for the determination of whether there is a good region present, then in an optical image analysis of radiative reflection from the enclosure, the region defined as the good region may be that for which the distance between the substrates is less than or equal to 3* A /2 = 750 nm. The method may also comprise the following step: igniting a plasma discharge in the mixing zone by means of a laser to prepare the laser joining operation. The scope of the invention also comprises the enclosure produced by the method presented above. A connected arrangement according to the invention or a sealed enclosure according to the invention can be used in such a way that it is used in contact or touching contact with biological material, in particular plant, human or animal cells. For example, the enclosure may be grown together with the biological material. Because the hermetically connected arrangement advantageously can be configured such that it contains no toxic and/or allergenic substances, it also does not release them. The hermetically connected arrangement or enclosure is therefore preferably arranged and configured such that it exerts no damaging action on biological material. Advantageously, the arrangement according to the invention has a reduced allergy potential when it comes into contact with the human or animal body or plant material, for example when it is incorporated therein and/or applied thereto. Exemplary applications of the arrangement according to the invention are medical implants, in particular medical intracorporeal sensors and/or wearables, which are applied to or arranged in the human or animal body or else plant material in the operating state. Typical wearables are fitness trackers and smart watches, that is to say electronic appliances which in particular can measure or monitor the physical state or physiological (physical) parameters. Further applications are of course possible and likewise comprised by the invention, for example such wearables that can influence physiological (physical) parameters, or other applications. The invention will be explained in more detail below on the basis of exemplary embodiments and with reference to the figures, with identical and similar elements in part being provided with the same reference signs and it being possible to combine the features of the various exemplary embodiments with one another.

Brief description of the figures

In detail:

fig. 1 shows a first embodiment of a hermetic assembly, fig. 2 shows a plan view of a hermetic assembly, here in the form of an enclosure with a functional region, fig. 3 shows a lateral sectional view of a hermetic assembly with a functional region as cavity, fig. 4 shows a lateral sectional view of a detail of the joining zone in one embodiment, fig. 4a shows a lateral sectional view of a detail of the joining zone in another embodiment, fig. 5 shows a lateral sectional view of a detail of another joining zone, fig. 6 shows a lateral sectional view of a hermetic assembly with a joining zone, fig. 7 shows a lateral sectional view of a substrate stack with spacers, fig. 8 shows a lateral sectional view of a hermetic assembly with a spacer, fig. 9 shows a digital photograph of a joined hermetic assembly, fig. 10 shows a lateral sectional view of a hermetic assembly with a plurality of laser spots, fig. 11 shows a lateral sectional view of a hermetic assembly with a plurality of laser spots and spacers, fig. 12 shows a laser arrangement for generating the laser join, figs. 13 to 17 show micrographs of a respective joined substrate stack, fig. 18 shows a photographic representation of a sample for evaluating the hermetic nature that can be achieved, fig. 19 shows a schematic illustration of the measurement of the quality factor, fig. 20 shows a flow diagram for measurement of the quality factor, fig. 21 shows a flow diagram relating to individual steps in the determination of the quality factor.

Detailed description of the invention

With reference to fig. 1, a first embodiment of a hermetic assembly 1 according to the invention is illustrated, with a metal first substrate 3 being arranged underneath a dielectric 4. The dielectric 4, or second substrate 4, is placed on the metal substrate 3 such that it comes to lie by way of its inner side 11 on the inner side 12 of the first substrate 3. The two substrates 3, 4 are thus in contact with one another. Depending on the specific surface finish (cf. e.g. fig. 6), the contact area can make up the entire respective inner side 11, 12, and/or the substrates 3, 4 can be in touching contact with one another extensively. The substrates 3, 4 may also be in touching contact only partially or in certain regions. When the substrates 3, 4 are stacked one on the other, gravity already causes the provision of a minimum amount of touching contact between the two substrates 3, 4, unless they are kept apart, for example by means of spacers 35 (cf. e.g. fig. 7).

In the example of fig. 1, three laser joining lines 6a, 6b, 6c or binding points 6a, 6b, 6c are introduced in order to join the two substrates 3, 4 to one another. The joining points/lines 6a, 6b, 6c are placed along the sides of the substrates 3, 4, wherein the joining points are inserted from above (in relation to the drawing) by means of a laser (cf. fig. 12). Here, the focal plane is set in the region of the inner faces 11, 12. Preferably, the focal plane is set such that it already comes to lie in the metal substrate 3, for example is offset 10 to 20 p m into the metal substrate 3, that is to say 10 to 20 p m below the inner face 12 of the metal substrate 3. This can have the effect that the laser beam 6a, 6b, 6c in the contact plane 15 reaches the desired width of preferably 4 p m +/-1 p m, more preferably 4 p m +/- 2 p m, more preferably 4 p m +/- 3 p m. This width can also be reached by corresponding beam shaping upstream of the lens. When, in the case as shown in fig. 1, the two substrates 3, 4 come to lie one on the other with their inner sides 11, 12 directly adjacent, that is to say in particular in extensive touching contact, the contact plane 15 also equates to the two inner sides 11, 12, as shown in fig. 1. Fig. 1 already illustrates three laser joining lines 6a, 6b, 6c, which are offset overlappingly in one another, with the result that the laser joining lines 6a, 6b, 6c also interact with one another. In this respect, various effects can be brought about or achieved depending on the aim. For example, the laser joining lines can be placed not warm-in-warm, but rather the successive laser joining line 6b is only inserted when the previous laser joining line 6a has already cooled down. The cooling-down process of the laser joining line is carried out extremely quickly here, since only an extremely small total amount of thermal energy is input and the metal material of the metal substrate 3 predominantly has excellent thermal conductivity. By means of the first laser joining line 6a, material of the two substrates 3, 4 is already mixed with one another and possible unevennesses and distances (air gaps 26) are meltingly bridged. Depending on the surface quality, for example in the event of large air gaps 26 of up to 5 p m in the region of the contact area 15 to be joined, the joining here with the first laserjoining line 6a may possibly fall just short. Since the region of the contact area 15 to be joined, however, is closed with the introduction of the first laser joining line 6a, the air gaps 26, if they were present beforehand, are closed and the material is already at least "blended", it is then possible to bring about optimum further mixing of the two materials of the substrate 3, 4 by means of the introduction of a second laser joining line 6b and, if appropriate, a third laser joining line 6c. Fig. 2 shows a plan view of a hermetic assembly 1, with the laser joining lines 6a, 6b, 6c being guided all around a functional region 2. In the figures, for the sake of simplicity, typically three laserjoining lines 6a, 6b, 6c are illustrated, but it is also possible for fewer or more laser joining lines 6, 6a, 6b, 6c to be inserted. The laser joining lines 6a, 6b, 6c are guided all around the functional region 2 in order to hermetically seal the functional region 2. In this case, the melted zone around the laser joining lines has a width w. It is possible, for example, for an object to be accommodated 5, such as an electronic circuit, to be arranged in the functional region 2 (cf. fig. 3). Fig. 3 shows a hermetic enclosure 9 with a hermetic assembly 1, wherein a cavity 2 is hermetically sealed. Three laser joining lines 6a, 6b, 6c, which hermetically join the second substrate 4 to the first substrate 3 in a fully closing manner and establish an inseparable bond, are introduced all around the cavity 2. The same reference signs denote the same parts in comparison with figure 1. Fig. 4 shows a view of a detail of a laser joining point of a laser joining line 6 or a binding point 6 with meaningful details which can explain the wide variety of refinements of the present invention. Against the background of the known joining method already handed down in house by the applicant, the present invention is concerned with the consequent further development and optimization of various joining processes between substrates 3, 4. The focus of the present invention here is on the binding or joining of two different substrates 3, 4, in particular in this case a metal substrate 3 with a dielectric 4, that is to say in particular a glass, glass-ceramic, sapphire or the like. In this respect, the very different CTE values of the differing materials, but also the different brittlenesses, inter alia, must be taken into account. For instance, it may be the case that undesired cracks or even holes or pores arise in the dielectric 4 while the materials are being joined. These arise partially on account of the thermal expansion in the laser joining line 6, which takes place with the ultra-fast input of heat into the dielectric 4 by the laser. They can cause such considerable impairment that the second substrate 4 can easily be broken off from the first substrate 3, that is to say the material of the second substrate 4 breaks "next to the joining line". In addition to the mechanical properties, such cracks can, however, additionally also impair the optical properties, and also jeopardize the established hermetic nature. These cracks 67 and pores 68 should therefore particularly advantageously be avoided. The laser joining point 6 shown in the lateral section in fig. 4 has a mixing zone 62, which extends into the metal substrate 3 and the dielectric 4 and in the process also bridges the sketched air gap 26. For example, the size of the air gap 26 in the region of the laser joining point 6 should be less than or equal to 5 p m, in order to ensure adequate generation of the laser joining point 6. For this, for example, it is important that first of all a plasma in the laser joining point 6 is ignited by inserting the laser, which plasma might not allow larger clearances to be bridged. The plasma ignition in turn is a prerequisite for being able to apply a significant punctiform amount of heat to the laser joining point 6 by means of the laser. The example of fig. 4 illustrates a resolidified zone 64 in the dielectric 4 (second substrate) which extends a long way into the second substrate 4. This therefore represents an unfavorable case which has caused numerous cracks 67 and pores 68. The margin 66 of the resolidified zone should then also be verified in the finished product, for example using a microscope, as the margin of the material modification in the second substrate 4. The example of fig. 4 does not illustrate a resolidified zone underneath the mixing zone 62, that is to say in the first substrate 3, since first of all the influence in the dielectric 4 is to be explained (cf. fig. 5, however, for this). In the mixing zone 62, material of the first substrate 3 is mixed with material of the second substrate 4, when the two materials are transferred a molten state at the same time. In a simple case, the two materials of the substrates 3, 4 have sufficient affinity, with the result that sufficient adhesion and thus a sufficient holding force of the second substrate 4 on the first substrate 3 (and vice versa) is established already by virtue of the mixing in the mixing zone 64. The first substrate 3 may comprise, for example, copper, silver, gold, iron, aluminum, titanium or else alloys such as steel, this list being non-exhaustive. The possibly present air gap 26 is less than or equal to 0.5 p m in the region of the (later) laser joining zone 6. When the distance in the contact area 15 is less than or equal to 0.5 p m, for example the contact area 15 is also labeled as good area G. In the case of only one laser joining line 6, 6a, 6b, 6c or binding point, the width W of the laser joining line corresponds approximately to the beam width 2wLaser in the contact area (15) that is generated by the laser generator (cf. fig. 12). In the case of N parallel laser joining lines 6, 6a, 6b, 6c, the width W of the generated laser joining line is usually less than or equal to N times 2 the beam width wLaser in the contact area (15), since for example an overlap of the laser active region is sought. Hm describes the height of the mixing zone 62, and Hr describes the height of the resolidified region 64. Ideally, Hmis greater than or equal to Hr; however, this is clearly not the case in the example of fig. 4, in order to explicitly show the relationships. Fig. 4a shows the lateral sectional view of a detail of the joining zone in another embodiment in which, in particular before the hermetically tight connection of the at least two substrates 3, 4 to one another by directly joining the at least two substrates 3, 4, a first covering or coating 70 is arranged on the metal first substrate 3 at least in the region of the laser joining line 6, 6a, 6b, 6c, 6d or the plurality of binding points on a side facing toward the second substrate 4, in particular to directly and immediately join the first metal substrate to the second substrate. This covering or coating 70 can be applied by various methods comprising, for example, physical and/or chemical deposition methods, such as physical vapor deposition (PVD), chemical vapor deposition methods or else an ALD method (atomic layer deposition), and may in particular also alternatively be applied as a local structure by printing techniques, such as screen printing or 3D printing. Another form of application can be effected while floating the substrate on liquid metal. The joining method described in the present case makes it possible for material of the first substrate 3 and material of the first covering or coating to be mixed in in the mixing zone 62 and/or at least in a region of the first substrate 3 that is close to the surface. In this respect, advantageously and in particular, the morphology of the microstructure in the mixing zone can be modified by the material of the first covering or coating. In certain embodiments, in the mixing zone, an alloy which at least comprises material of the metal first substrate 3 and the first covering or coating can be formed at least in certain regions. Particularly advantageously, this alloy can form a eutectic when a corresponding amount of the coating or covering is made available for the joining operation. This amount can be implemented by selecting the thickness D 1 of the first covering or coating. This thickness D1 may, for example, be between 0.1 and 5 p m. Preferably, the metal first substrate 3 may comprise or consist of iron, steel or an iron containing alloy and the first covering or coating may comprise or consist of carbon. With this selection of material, locally higher carbon-containing regions can be provided in or on the mixing zone 62. Without restriction of the generality and without restriction by the example disclosed above, consolidation of the bond between the first and the second substrate can be brought about by means of the mixed-in material of the first covering or coating. In this respect, within the scope of the present disclosure, consolidation refers to an increase in the forces which are required to separate the joined substrates 3, 4 after the joining operation. These forces can be introduced perpendicularly in relation to the respective surface of the substrate 3, 4 at which these substrates touch, it then being the case as a result that the strength to resist pulling apart can be determined and specified, or else introduced transversely in relation to this surface, it then additionally being the case that the strength with respect to proportional shear forces can be determined and specified. In connection with the first and the second covering or coating disclosed in the present case, consolidation is understood to mean the increase in these aforementioned forces in the case of a joined connection that makes use of this first and/or second covering or coating compared to a joined connection which does not make use of a first and/or second covering or coating. As an alternative or in addition, in particular before the hermetically tight connection of the at least two substrates 3, 4 to one another by directly joining the at least two substrates 3, 4, for a second covering or coating 71 to be arranged on the second substrate 4 at least in the region of the laser joining line 6, 6a, 6b, 6c, 6d or the plurality of binding points on a side facing toward the first substrate 3, in particular to directly and immediately join the first metal substrate 3 to the second substrate 4. The covering or coating 71 on the second substrate 4 may comprise or consist of a composition by means of which it is possible to develop a compressive stress in a compressive stress zone Ds within the second substrate 4 in a zone of the second substrate 4 which is close to the surface and extends perpendicularly in relation to the surface of the second substrate, at least to a depth DoL. In preferred embodiments, material of the second substrate 3 and material of the second covering or coating 71 is mixed in or introduced in the mixing zone 62 and/or at least in a region of the second substrate 4 which is close to the surface, as a result of which a correspondingly localized compressive stress zone can be formed. In this respect, the second substrate 4 comprises or consists of a material in which at least compressive stresses close to the surface can be introduced in a compressive stress zone Ds and the first covering or coating comprises or consists of a material which makes it possible to introduce compressive stresses into the material of the second substrate 4, in particular by ion exchange. Such glasses and/or glass articles and materials for introducing compressive stresses within a compressive stress zone Ds are described, for example, in US 2018/0057401 Al, US 2018/0029932 Al, US 2017/0166478 Al, US 9,908,811 B2, US 2016/0122240 Al, US 2016/0122239 Al, US 2017/0295657 Al, US 8,312,739 B2, US 9,359,251 B2, US 9,718,727 B2, US 2012/0052271 Al, US 2015/0030840 Al or else DE 10 2010 009 584 B4 and CN 102690059 A. By way of example, the material of the second substrate may generally comprise or consist of a glass, in particular a soda-lime silicate glass or borosilicate glass, and the material of the second covering or coating 71 may comprise a compound suitable for giving up exchangeable ions, in particular a sodium and/or lithium compound, in particular sodium nitrate and/or lithium nitrate. It is also possible here for the thickness of the second covering or coating 71 preferably to be from 0.1 to 5 p m and it is also possible here for a consolidation of the bond between the first and the second substrate to be brought about by means of the mixed-in or introduced material of the second covering or coating 71. Fig. 5 shows another embodiment of a view of a detail of a laser joining line 6, and once again the same reference numbers used in other figures are also assigned to the same features. In this embodiment, the laser joining line 6 additionally also has a resolidified region 69 in the first substrate 3 that extends underneath the mixing zone 62. It should be assumed that the mixing zone 62 merges directly into the respective resolidified zone 64, 69. The mixing zone 62 is distinguished in that, here, a mix of material is present, that is to say the mixing zone 62 comprises material of the first substrate 3 and material of the second substrate 4. However, it is also possible for material of a substrate 3, 4 to be able to be introduced into the respective other substrate, for example in the form of slivers 4a or dendrites 4b, and it was also possible already to observe and adjust this. Metal material of the first substrate 3 can also be channeled into the second substrate 4, for example in the form of droplets 3a. Such droplets 3a may be "channeled" multiple micrometers into the second substrate 4. The dendrite 4b illustrated in fig. 5 may be of particular interest, since such embodiments make it possible to achieve a considerably improved adhesion of the two substrates 3, 4 to one another. A dendrite 4b acts in this respect possibly as an anchor or nail when it engages in serrated fashion with the material of the other substrate or is inserted at an angle to the perpendicular. The two materials of the different substrates 3, 4 in this respect, for example, have little affinity with one another and do not adhere to one another even in the molten state. In that case, such a dendrite 4b or serrated engagement in the mixing zone 62 may be the best option to set an adhesive action or holding force between the two substrates 3, 4. With reference to fig. 6, an assembly 1 with a laser joining line 6 on one side is shown. The air gap 26 in this example, in the contact region 15 of the laser joining line 6, is just small enough to introduce the laser joining line 6, but at other regions of the inner sides 11, 12 is larger on account of unevennesses 31, 32 of the surface. Both a depression 31 and an elevation 32 can be disadvantageous for the introduction of the laser joining line 6 in this respect. In principle, it has been found that it is advantageous when the surfaces 11, 12 are smooth, for example with a mean roughness of 0.1 p m or better. This is surprising to start with, because a particularly smooth surface reflects well and therefore difficulties are involved in being able to introduce an energy deposition in the assembly by means of a laser at all. Fig. 7 shows an embodiment of a substrate stack 1 which is yet to be joined, wherein spacers 35 are inserted between the substrates 3, 4 in order to set a defined distance between the substrates 3, 4. Within the scope of the present invention, it has been shown that air gaps 26 can be tolerated as long as the distance between the substrates 3, 4 in the region of the contact region 15 to be joined is small enough, for example less than 5 p m, better less than 2 p m, preferably less than 0.5 p m. The example of figure 7 also shows that the use of spacers 35 makes it possible to easily compensate even rougher unevennesses of the substrates 3, 4, since the distance between the substrates no longer needs to be established by extensive contact between the inner sides 11, 12. Furthermore, the air gap 26 can take on another task in that it provides a flow zone 40 which material of the substrates 3, 4, material of the substrate 4 being of particular importance here, can enter, when said material is molten. In this way, cracks and gaps in the second substrate 4, if appropriate, can be reduced or even completely avoided. Fig. 8 shows the exemplary embodiment of fig. 7, wherein a laser spot 6 has been introduced on the left-hand side in the region of the contact region 15. Here, material of the second substrate 4 has then run into the flow zone 40. In the mixing zone 62, material of the first substrate 3 mixes with material of the spacer 35 and with material of the second substrate 4. The mixing zone 62 extends both into the first substrate 3 and into the second substrate 4. Given a suitable selection of material for the spacer 35, this makes it possible to increase the adhesion property even further if, for example, material is selected which has somewhat of an affinity with the material of the first substrate 3 and with the material of the second substrate 4. A flow zone 40 may also be provided as recess in one of the substrates 3, 4 (not illustrated). The flow zone 40 advantageously extends along the intended laserjoining zone, with the result that material can constantly flow into the flow zone 40, in order to absorb pressure spikes or even not allow them to form in the first place and thus reduce the production of cracks and holes 67, 68. Fig. 9 shows a photographic representation of a hermetic assembly 1 corresponding to figure 6. Unevennesses such as scratches 31 or burrs 32 that might impair the hermetic nature of the assembly 1 have been eliminated. With reference to fig. 10, another aspect of the present invention is to be explained in more detail. The sequence of a plurality of laser spots for the consecutive generation of a laser joining line 6 is illustrated, the spots 1, 2, 3, 4, 5 being inserted in succession. The spots here are made warm-in-warm and partially overlap in this case, since the width w of the beam focus is greater than the distance d between the target points or the laser spots. This makes it possible to achieve a further improvement of the mixing in the mixing zone 62 and thus of the adhesion. A similar effect is achieved in all other respects if the laser spots illustrated in fig. 10 are not thought of as belonging to a certain laser joining line 6, but rather to 5 different laser joining lines 6, 6a, 6b, 6c, 6d, which are inserted into the material next to one another. In both cases, the hermetic nature and/or the holding force holding the substrates 3, 4 to one another are enhanced. Fig. 11 then shows another embodiment, it likewise being the case that a plurality of laser spots 6 is inserted in the contact area 15, and the two substrates 3, 4 here are arranged spaced apart from one another by means of spacers 35. When the one or more spacers 35 for example are made small enough, that is to say e.g. thinner than 5 p m (for example in the form of a film, metal foil, or vapor-deposited, sputtered on, or in the form of a Litho-glass layer), the remaining air gap 26 can be bridged directly by means of the laser. In the case of the subsequent laser spots, which partially overlap the respective previous laser spot, here the air gap is no longer an obstacle, since the air gap is already partially bridged or closed. When the distance is to be set as larger, a spacer 35 can serve as "start point" for the laser joining process and it can be fused (as shown in fig. 6). The further laser spots partially overlap the first "start spot" and can therefore also be made at larger distances between the substrates. This also makes it possible to bridge distances between the substrates that are greater than 5 p m, for example also greater than 10 p m, or even up to 20 p m and more. The height of the laser spot here may be set to 50 p m, up to for example 100 p m. For example, the distance d from one laser spot to the next can be set to d < 10 p m, preferably d < 6 p m, more preferably < 4 p m. In the example of figure 11, by virtue of the spacer 35 the interaction zone 62 is kept out of the second substrate 4 to a greater extent, and the mixing zone 62 thus extends only slightly into the second substrate 4. The penetration of the mixing zone 62 can be set, for example, to just 1 p m ±0.8 p m. In that case, the resolidified zone 64 in the second substrate 4 can in particular completely or largely disappear and the mixing zone 62 can nevertheless extend deep enough into the second substrate 4 to ensure a bond. The left-hand side of fig. 12 sketches a laser generator 80 for generating the laser spot 6 in the hermetic assembly 1. In this possible embodiment, the processing head 801 contains a mirror 802 tilted at 450 and the inscription lens 803. Here, the processing head is moved parallel to the laser beam of the laser source 806 in the x direction, 804. Relative to this, the arrangement

1 or the substrate stack is moved perpendicularly thereto on a separate processing table in the direction y, 805. Moreover, in the right-hand side of fig. 12, an intensity profile 82 of the heat output is sketched for the case in which three laser joining lines 6a, 6b, 6c are introduced warm in-warm in the hermetic assembly 1. The flanking laser joining lines 6a, 6c can thus bring about further-intensified mixing in the middle joining line 6b. Fig. 13 shows a micrograph of a produced hermetic assembly 1, with use being made of aluminum as first substrate 3 and sapphire as second substrate 4. It was already successfully possible to implement the occurrence of the mixing zone 62 practically exclusively in the second substrate 4, and it was possible to largely prevent cracks or holes in the second substrate. A dendrite 4b can be clearly seen, with sapphire 4 having penetrated or been mixed in the metal of the first substrate 3 and there in the resolidification zone 69. This can significantly increase the holding force holding the sapphire 4 to the aluminum 3. It was also possible to identify a particle 4a of the sapphire in the resolidification zone 69 of the first substrate 3. Fig. 14 shows another micrograph, with the assembly shown in fig. 13 being shown to a more enlarged extent and once again in a false-color illustration. The generation of the dendrite 4b is extremely surprising and can possibly be described as groundbreaking. Already for this reason, this agreeable new development in house by the applicant is to be presented as completely as possible and by means of various illustrations. However, overall the quality of the connection produced and the considerable reduction of the resolidified zone 64 in the second substrate 4 are also strong indicators that the present invention can smooth the way for a broad range of products. Fig. 15 shows another micrograph, with steel being selected as first substrate 3 and sapphire as second substrate 4. In this example, a clear resolidified zone 64 above the mixing zone 62 in the sapphire 4 can be seen, also with clear cracks 67. The sapphire has not penetrated the steel in this example. For this, by means of the beam settings, it was possible to generate such a rough, serrated surface with the laser spot 6 on the first substrate 3 that a serrated structure 37 was provided, which likewise increases the adhesion of the hermetic assembly 1. Fig. 16 shows another micrograph, with titanium being selected as first substrate 3 and sapphire as second substrate 4. In this example, it was possible likewise already to have the effect that there is no noteworthy distinctive resolidified zone 64 in the second substrate 4, with the result that stresses or cracks 67 are scarcely introduced in the second substrate 4. The material of the first substrate 3 has channeled astonishingly far into the second substrate 4 in the mixing zone 62 and there forms comb-like structures, which likewise have the effect of an extraordinary serrated engagement of the hermetic assembly 1. Fig. 17 lastly shows yet another micrograph, with copper being selected as first substrate 3 and sapphire as second substrate 4. In this example, too, it was possible to practically eliminate the resolidified zone 64 in the second substrate 4. In this example it is possible to see droplets 3a which have penetrated a few micrometers into the second substrate 4, but also dendrites 4b and melted portions 4a of the second substrate 4 that have penetrated the first substrate 3. In this example, too, it was possible thus already to considerably improve the adhesion. Within the scope of the invention, a series of measurements was also taken to ascertain the hermetic nature. In this respect, for 61 samples 1a, a leakage rate (mbar x liters/sec) for a respective sample 1a was ascertained. Fig. 18 shows by way of example a copper sample 1a for ascertaining the leakage rate, with a sapphire disk 4 being laser-joined to a metal component 3. The leakage rate was ascertained by means of a spray-on technique. For example, at standard pressure or else in a low-pressure environment (vacuum), a helium gas is suitable for spraying the gas onto the sample and measuring possible diffusion into the interior of the sample 1. A pressure difference between the outer side and the inner side of the sample 1a of 1 bar has proven to be advantageous. Various metal samples 1a were measured, with an in particular hermetic assembly 1 being produced by arranging a sapphire disk 4 on a metal component 3 and laser-joining them. Aluminum samples, titanium samples, steel samples and copper samples, each of which were laser-joined to a sapphire substrate 4, were measured as metal component 3. The lower measurement limit of the apparatus used to check the hermetic nature was at a leakage rate of 1 x 10-9 mbar I/s. It can be assumed that a completely hermetic nature is achieved with application of the spray-on test and achievement of a leakage rate of 1 x 10-7 mbar x Is-i or less, preferably 1 x 10-8 mbar x Is-i or less, more preferably 1 x 10-9 x Is- or less The following table shows, by way of example, 12 samples 1a, with the metal component 3 used to produce the hermetic assembly 1 (substantially) consisting of aluminum in the case of the three samples denoted "Al", (substantially) consisting of titanium in the case of the samples denoted "Ti", (substantially) consisting of iron in the case of the samples denoted "St" and (substantially) consisting of copper in the case of the samples denoted "Cu".

Sample Leakage Sample Leakage Sample Leakage Sample Leakage designation rate design- rate designation rate designation rate

[mbar x ation [mbar x [mbar x [mbar x liter / s] liter / s] liter / s] liter / s]

01 Al <1E-09 11 Ti <1E-09 22 St <1E-09 41 Cu 7E-09 02 Al <1E-09 15 Ti <1E-09 25 St <1E-09 44 Cu 6E-09 03 Al <1E-09 20 Ti 2E-08 26 St <1E-09 52 Cu 8E-09

All of the samples la reproduced here are therefore to be designated as hermetically tight within the meaning of the previous definition. Particularly, it should be emphasized here that the samples with aluminum and steel have such a small leakage rate that it was no longer possible to further resolve them by means of the apparatus used given a lower measurement range limit of 1 x 10-9 x Is-i. The hermetic nature actually achieved is therefore better than the lower measurement range limit, and thus less than 1 x 10-9 x Is-. Optionally, the quality of the hermetic assemblies 1 created should be made checkable. For this, it can be appropriate in any case to establish a distance profile in the region of the laser joining connection before its introduction. Fig. 19 shows, here for comprehension purposes, a detail of a substrate stack 9, with a fault region 17, a touching-contact region 18 and a good region 19 being visible. The double-headed arrow 21 describes the location of the greatest height of the defect 17. The radiative input 22 is directed at the substrate stack 9, with the radiative input being reflected both on the inner side 11 of the first substrate 3 and on the inner side 12 of the second substrate 4 in the region of the defect 17. The radiative reflection 24, 24a can be detected by means of the detector 30. The difference in the path taken by the radiative reflection 24 and the radiative reflection 24a leads in this case to an interference pattern, which is generated by the two radiative reflections in relation to one another. In the case of the transparent substrate (4), this involves Fresnel effects, that is to say, for example, reflections. In the case of glass without an antireflection coating, these reflections can, for example, amount to approximately 4% per interface in each case. In the case of the metal substrate (3), the reflection arises as a result of the polished surface. The radiative input 22 in this case comprises monochromatic light. Consequently, interference patterns can be read, in particular Newton rings, and from these a magnitude of the distance between the substrates can be obtained. Fig. 20 shows steps of the method for producing or checking the hermetic assembly of a substrate stack. In a first step 100, a first substrate is extensively arranged on a second substrate. In a second step 110, a height profile of the gap within the substrate stack 9 is ascertained from the detection of a radiative reflection, which is produced by irradiating the substrate stack with a radiative input 22 on at least one contact area of the substrate stack 9. In a step 120, the bond quality index Q1 is ascertained from the height profile. In a decision step 130, a determination is made, provided that the bond quality index Q, ascertained in step 120 is greater than a specified, permitted threshold value Qlthr, that the substrate stack can in that case be released for further processing, that is to say in particular for laser joining by means of laser joining lines 6. Should Qi, however, be less than the achieved or desired Qthr, then, in step 135, the substrate stack 9 is for example reworked, i.e. it is disassembled, recleaned if appropriate, or fed for reutilization of some other kind. In step 140, the substrate stack 1 is then laser-joined to form the one or more enclosures. Subsequently, a second height profile of the gap within the substrate stack of the attached substrate stack 1 is ascertained in the step 150, and from this Q2 is calculated in the step 160. In the step 170 it is ascertained whether Q2 is greater than a threshold value Q2thr specified for Q2. For example, Q2thr is lessthan or equal to Qthr. Preferably, in step 170, it is likewise ascertained or checked whether Q2 at any rate is equal to or greater than Q. If both conditions are met, the joined enclosure 1 or enclosures 1 can be processed further in a step 180, for example the plurality of enclosures 1 can be separated from the wafer stack 9 at the separating line 8. If, conversely, one of the two conditions or both conditions specified in step 170 has not or have not been met, then in a step 175 an alternative further treatment of the substrate stack 9 may be introduced; in this case, for example, there may be labeling of fault regions F, 17 or the wafer stack 9 may be fed for reclamation. Fig. 21 describes certain steps which can be carried out in order to calculate the bond quality index Q, and/or Q2. In a step 121, first of all image data from the detector 30 are obtained, for example by means of an operational computer tailored to that purpose. In step 122, the image data obtained in step 121 are converted to a grayscale pattern or the red channel is extracted from the image data. It may be processed by means of an image-processing functionality which runs, for example, on the same computer on which the image data are also obtained with step 121. With step 123, the physical margins of the substrate stack 3, 4, 9 are ascertained in the recorded image from the detector 30, for example in the form of corner recognition. In a step 124, the perspectives can be corrected or equalized, should it be necessary. In a step 125, the contrast can be improved, for example in the region of the substrate stack. In this case, for example, it is possible simply to subtract the darkest gray background value and to generate a grayscale image from a black-and-white image. In a step 126, lastly, a height profile is calculated from the image data obtained by means of the detector 30, for example on the basis of established Newton rings. After that, in a step 127, it is possible to label and integrate regions in which critical heights or profiles have been established. This relates in particular to regions which have been established as a fault region F, 17. In a step 128, lastly, the respective Q factor Q1 or Q2 is calculated from the image data corrected or improved as described above. It was therefore possible, with the present description, to completely and comprehensibly disclose a method for being able to join two different substrates to one another by means of a laser joining method, in particular a metal substrate to a dielectric, such as a glass substrate or crystal. It was also possible to illustrate the corresponding hermetically joined assembly in detail and explain it so that it can be reproduced. The present description comprises a multiplicity of descriptions which might contradict "conventional" knowledge or be possible to find surprisingly. For this reason, too, results were also documented using micrographs in order to illustrate that it was already possible to convert the invention presented into actual results. It is evident to a person skilled in the art that the embodiments described above should be understood as exemplary and the invention is not limited to them, but instead can be varied in a wide variety of ways without departing from the scope of protection of the claims. It is also evident that the features, irrespective of whether they are disclosed in the description, the claims, the figures or otherwise, also individually define essential constituents of the invention, even if they are described jointly together with other features. In all of the figures, the same reference signs denote the same features, and therefore descriptions of features which might be mentioned only in one figure or at any rate not in relation to all the figures can also be transferred to those figures for which the feature is not described in the description.

List of reference signs

1 Assembly or substrate stack 1a Sample 2 Functional region or cavity 2a, 2b Cavities in the region of a defect 17 3 First substrate (containing metal) 3a Droplet 4 Second substrate (dielectric, e.g. glass) 4a Melted portion or droplet of the second substrate 4b Dendrite of the second substrate Object to be accommodated 6, 6a, 6b, 6c Joining zone or laser bond line 8 Separating line 9 Enclosure 11 Contact area or inner side of the first substrate 12 Contact area or inner side of the second substrate Contact area 17 Fault region or defect F 18 Touching-contact area B 19 Good area G Radiation source 21 Maximum distance between the two substrates 22 Radiative input 24, 24a Radiative reflection 26 Possible air gap Detector 31 Depression 32 Elevation Spacer 37 Serrated structure Flow zone 62 Melt zone or mixing zone

64 Resolidified zone 66 Margin of the resolidified zone 67 Cracks, fissures 68 Pores 69 Resolidified zone First covering or coating 71 Second covering or coating Laser generator 82 Intensity profile 100 Arrangement step 110 Step of ascertaining the height profile 120 Calculation step for the first bond quality index Q1 121 Data provision 122 Converting step 123 Detection step 124 Correction step 125 Contrast improvement 126 Calculation step for the height profile 127 Labeling step 128 Calculation step for the Q factor Q1 and/or Q2 130 Evaluation step for Q1 135 Feedback step 140 Further-treatment step, in particular laser joining 150 Ascertainment of the second height profile 160 Calculation step for Q2 170 Evaluation step for Q2 175 Labeling step in the event of a fault 180 Final treatment, in particular singularization of the arrangement 1 or enclosures 9 801 Processing head of the laser generator 802 Deflection mirror 803 Laser lens 804 Movement direction of the processing head

805 Movement direction of the substrate 806 Laser beam of the laser beam source d Distance between two laser joining lines or two binding points N Protected region W Width of the laserjoining line 6 Di Thickness of the first covering or coating 70 D2 Thickness of the second covering or coating 71 Ds Compressive stress zone DoL Depth of the compressive stress zone

Claims

Patent claims:

1. A hermetically connected arrangement (1) comprising: a first metal substrate (3), a second substrate (4), which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area (11), is arranged adjacent to a contact area (12) of the second substrate, at least one laser joining line (6, 6a, 6b, 6c, 6d) or a plurality of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas (11, 12, 15), wherein the laser joining line or the plurality of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another.

2. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein a mixing zone (62), in which material of the second substrate (4) and material of the first substrate (3) are merged, is present in the laser joining line (6, 6a, 6b, 6c, 6d) or the plurality of binding points.

3. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein metal material of the first metal substrate (3) has entered the second substrate (4) in the mixing zone (62), and/or wherein material of the second substrate (4) has entered the first substrate (3) in the mixing zone (62).

4. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the mixing zone (62) has a thickness measured in a direction perpendicular to the contact areas (11, 12, 15), and wherein the mixing zone has a thickness of preferably at least 1 p m, preferably 2 p m or more, more preferably 5 p m or more, and/or wherein the mixing zone (62) extends 1 p m or more into the second substrate.

5. The hermetically connected arrangement (1) as claimed in one of the two preceding claims, wherein the mixing zone (62) has a width, and the width of the mixing zone is greater than the thickness of the mixing zone in the second substrate (4), and/or the width of the mixing zone (62) is greater than the thickness of the mixing zone by 50% or more, more preferably is greater than the thickness of the mixing zone by 100% or more, wherein the width of the mixing zone (62) is measured in particular at the contact area (15) between the first and the second substrate (3, 4) and in a direction parallel to the contact area and perpendicular to the laser joining line (6, 6a, 6b, 6c, 6d).

6. The hermetically connected arrangement (1) as claimed in one of the preceding claims, the at least one laser joining line (6, 6a, 6b, 6c, 6d) or the plurality of binding points also having a resolidified zone (64, 69), wherein the resolidified zone has a thickness measured in the direction perpendicular to the contact areas (11, 12, 15), and wherein the thickness of the resolidified zone is preferably less than or equal to 20 p m, preferably less than or equal to 10 p m, more preferably less than or equal to 5 p m, and/or wherein the resolidified zone (64, 69) extends less than or equal to 20 p m, preferably less than or equal to 10 p m, more preferably less than or equal to 5 p m, into the depth of the second substrate.

7. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein the resolidified zone (64, 69) extends along the laser joining line (6, 6a, 6b, 6c, 6d), and/or wherein, at the contact area (11, 12, 15) between the first and the second substrate (3, 4) and in a direction parallel to the contact area, the resolidified zone (64, 69) has a width of 10 p m 5 p m, preferably 20 p m ±10 p m, more preferably 30 p m ±10 p m, and/or wherein, at the contact area (11, 12, 15) between the first and the second substrate (3, 4) and in a direction parallel to the contact area and perpendicular to the laser joining line, the resolidified zone (64, 69) has a width that is greater than the thickness of the resolidified zone.

8. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein, in the mixing zone (62), material of the first substrate (3) and material of the second substrate (4) are arranged in such a way that a form-fitting serrated engagement between the material of the first substrate and the material of the second substrate is brought about, and/or having a fused-together serrated structure (37) between the first metal substrate (3) and the second substrate (4).

9. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein, in the mixing zone (62) and/or the resolidification zones (64, 69), metal material of the metal substrate (3) is present in the form of droplets (3a) and/or dendrites and/or material of the second substrate (4) is present in the form of melted portions (4a) and/or dendrites (4b), wherein the arrangement in the form of droplets and/or dendrites causes consolidation of the bond between the first and the second substrate.

10. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein metal material of the metal substrate (3) and/or material of the second substrate (4) has penetrated at least one of the resolidification zones (64, 69), in particular in the form of droplets (3a), melted portions (4a) and/or dendrites (4b), and causes consolidation of the bond between the first and the second substrate.

11. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the contact area (11) of the first substrate (3) has at least one touching-contact region in which the first substrate is in extensive touching contact with the second substrate (4), wherein the touching-contact area in particular has a mean distance between the first and the second substrate of less than or equal to 1 p m, preferably less than or equal to 0.5 p m, more preferably less than or equal to 0.2 p m, and/or wherein the touching-contact area in particular corresponds to the contact area (15).

12. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the laser joining line (6, 6a, 6b, 6c, 6d) connects the first substrate (3) to the second substrate (4), with the result that the two substrates can be separated from one another only by applying a holding force, or only by destroying the second substrate if the holding force is greater than the force necessary to destroy the second substrate, and/or wherein a holding force of the second substrate on the first substrate is greater than 10 N/mm , preferably is greater than 25 N/mm , more preferably is greater than 50 N/mm , even 2 2 2 more preferably is greater than 75 N/mm and even more preferably still is greater than 100 2

N/mm 2 .

13. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the first substrate (3) is characterized in that the contact area (11) has a flat form, in particular planar form, and/or wherein the contact area (11) of the first substrate (3) is polished, and/or wherein the contact area (11) of the first substrate (3) has a mean roughness Ra of less than or equal to 0.5 p m, preferably less than or equal to 0.2 p m, more preferably less than or equal to 0.1 p m, even more preferably less than or equal to 50 nm and ultimately preferably less than or equal to 20 nm and/or wherein the second substrate (4) is characterized in that it has a flat form, in particular planar form, at the contact area (12), more particularly has a mean roughness Ra of less than or equal to 0.5 p m.

14. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein the joining laser has a beam focus, and wherein the focal plane for introducing the laser joining line (6, 6a, 6b, 6c, 6d) is offset distally, in particular is in the first substrate (3), and wherein the focal plane is displaced preferably 10 p m ±10 p m, more preferably 20 p m ±10 p m, distally into the first substrate (3).

15. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the beam width (2WLaser) in the contact plane (11, 12, 15) is 4 p m ±1 p m, preferably 4 p m ±2 p m, more preferably 4 p m ±3 p m.

16. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the first substrate (3) consists of metal material, and/or wherein the first substrate (3) comprises metal within the meaning of the definition of the Periodic Table of the Elements.

17. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the first substrate (3) comprises or consists of at least one of molybdenum, tungsten, silicon, platinum, silver or gold, and/or wherein the first substrate (3) comprises an alloy, in particular comprises or consists of at least one of carbon, copper, manganese, chromium, magnesium, cobalt, nickel, tin, zinc, niobium, palladium, rhenium, indium, tantalum, titanium or iridium.

18. The hermetically connected arrangement (1) as claimed in one of the preceding claims, wherein the second substrate (4) is a transparent substrate, and/or wherein the second substrate (4) comprises or consists of glass, glass-ceramic, silicon, sapphire or a combination of the aforementioned materials, and/or wherein the second substrate (4) comprises or consists of ceramic material, in particular oxide-ceramic material.

19. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein the second substrate (4) comprises or consists of at least one of quartz glass, borosilicate glass, aluminosilicate glass, a glass-ceramic such as Zerodur, Ceran or Robax, an optical ceramic such as aluminum oxide, spinel, pyrochlore or aluminum oxynitrite, calcium fluoride crystal or chalcogenide glass.

20. The hermetically connected arrangement (1), in particular as claimed in one of the preceding claims, comprising a first metal substrate (3), a second substrate (4), which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area (11), is arranged adjacent to a contact area (12) of the second substrate, at least one spacer (35) for establishing a distance between the first and the second substrate.

21. The hermetically connected arrangement (1) as claimed in the preceding claim, also comprising at least one laser joining line (6, 6a, 6b, 6c, 6d) or a plurality of binding points for directly and immediately joining the first metal substrate (3) to the second substrate (4), wherein the laser joining line or the plurality of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another.

22. The hermetically connected arrangement (1) as claimed in one of the two preceding claims, wherein the first substrate (3) is in contact with the second substrate (4) via a spacer (35), and/or wherein the spacer (35) is arranged between the first substrate (3) and the second substrate (4).

23. The hermetically connected arrangement (1) as claimed in one of the three preceding claims, wherein the spacer (35) extends at least along the laser joining line (6, 6a, 6b, 6c, 6d) or in the region of the binding points, or wherein the spacer (35) extends outside the laser joining line (6, 6a, 6b, 6c, 6d) or outside the region of the binding points, or wherein the spacer (35) is formed over the entire surface area, and/or wherein the spacer (35) has a thickness of at least 5 p m, more preferably a thickness of at least 10 p m, more preferably a thickness of at least 20 p m.

24. The hermetically connected arrangement (1) as claimed in one of the three preceding claims, wherein the spacer (35) consists of metal material, and/or wherein the spacer (35) is in the form of a coating on the first substrate (3) or the second substrate (4), and/or wherein the spacer (35) is formed in one piece with the first substrate (3) and/or the second substrate (4).

25. The hermetically connected arrangement (1), in particular as claimed in one of the preceding claims, comprising a first metal substrate (3), a second substrate (4), which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area (11), is arranged adjacent to a contact area (12) of the second substrate, and at least one flow zone (40) for receiving molten material from a laser joining line (6, 6a, 6b, 6c, 6d) or a binding point, wherein the laser joining line or a plurality of binding points is used for directly and immediately meltingly joining the first metal substrate to the second substrate.

26. The hermetically connected arrangement (1) as claimed in the preceding claim, wherein the at least one flow zone (40) is arranged adjacent to the laser joining line (6, 6a, 6b, 6c, 6d) or the plurality of binding points, and/or wherein the at least one flow zone (40) is arranged between the first substrate (3) and the second substrate (4), and/or wherein the at least one flow zone (40) is formed on the contact area (11, 12, 15) when the second substrate (4) is being arranged on the first substrate (3).

27. The hermetically connected arrangement (1), in particular as claimed in one of the preceding claims, comprising a first metal substrate (3), a second substrate (4), which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area (11), is arranged adjacent to a contact area (12) of the second substrate, a first laser joining line (6, 6a, 6b, 6c, 6d) or a first set of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas (11, 12, 15), wherein the first laser joining line or the first set of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another, a second laser joining line (6a, 6b, 6c, 6d) or a second set of binding points for directly and immediately joining the first metal substrate to the second substrate, on or in the contact areas, wherein the second laser joining line or the second set of binding points extends into the first laser joining line or the first number of binding points, respectively, and modifies or improves the mixing of material achieved by the first laser joining line or the first set of binding points.

28. A hermetically sealed enclosure (9), in particular having a hermetically connected arrangement (1) as claimed in one of the preceding claims, comprising a metal first substrate (3), a second substrate (4), which is transparent to at least one wavelength range at least in certain regions and/or at least partially, wherein the first substrate, by way of a contact area (11), is arranged adjacent to a contact area (12) of the second substrate, at least one functional region (2), in particular a cavity, arranged between the first and the second substrate, at least one laser joining line (6, 6a, 6b, 6c, 6d) or a plurality of binding points for directly and immediately joining the first substrate to the second substrate, on or in the contact areas, in particular around the functional region to hermetically seal off the functional region, wherein the laser joining line or the plurality of binding points extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another.

29. The hermetically sealed enclosure (9) as claimed in the preceding claim, wherein the laser bond line (6, 6a, 6b, 6c, 6d) of the enclosure is formed all the way around the functional region (2) so as to seal it, and/or wherein a distance between the first substrate (3) and the second substrate (4) in the laser bond line (6, 6a, 6b, 6c, 6d) is continuously less than 0.75 p m, preferably less than 0.5 p m, more preferably less than 0.2 p m.

30. The hermetically sealed enclosure (1) as claimed in one of the preceding claims, wherein the functional region (2) comprises a hermetically sealed accommodating cavity for receiving an object to be accommodated (5), such as an electronic circuit, a sensor or MEMS.

31. The hermetically connected arrangement (1) or hermetically sealed enclosure (1) in particular as claimed in one of claims 1 to 30, in the case of which, in particular before the hermetically tight connection of the at least two substrates to one another by directly joining the at least two substrates, a first covering or coating is arranged on the metal first substrate (3) at least in the region of the laser joining line (6, 6a, 6b, 6c, 6d) or the plurality of binding points on a side facing toward the second substrate, in particular to directly and immediately join the first metal substrate to the second substrate.

32. A method for producing a hermetically sealed assembly (1) from at least two parts, having the following steps: extensively arranging at least one first metal substrate (3) on a second substrate (4), wherein the at least two substrates are arranged on one another, with the result that a contact area (11, 12, 15), in which the first substrate is in contact with the second substrate, is formed between the at least two substrates, and wherein the second substrate comprises a transparent material, connecting the at least two substrates to one another in a hermetically tight manner by directly joining the at least two substrates to one another in the region of the at least one contact area, resulting in the formation of a mixing zone (62), which extends for the one part into the first substrate and for the other part into the second substrate and directly meltingly joins the at least two substrates to one another.

33. The method as claimed in the preceding claim, in the course of which a first covering or coating is arranged on the first substrate (3) before the at least one first metal substrate (3) is extensively arranged on the second substrate (4).

34. The method as claimed in either of the preceding claims 32 and 33, further comprising the following step: checking the hermetic assembly of the at least two substrates (3, 4) by ascertaining a distance profile between the at least two substrates, and/or ascertaining a first bond quality index Q1 by checking the mechanical strength and/or the hermetic nature of the assembly (1).

35. The method as claimed in the preceding claim, wherein the first bond quality index Q1 is ascertained by Q1 = 1 - (A - G) / A, wherein A represents the area of the contact area (11, 12, 15) and G represents a good area, wherein the good area G in particular corresponds to the touching-contact area, and/or wherein the good area G describes a part of the contact area (11, 12, 15) in which the distance between the substrates (3, 4) is less than 5 p m, preferably less than 1 p m, more preferably less than 0.5 p m, even more preferably less than 0.2 p m, and/or wherein the bond quality index Q1 is greater than or equal to 0.8, preferably greater than or equal to 0.9, more preferably greater than or equal to 0.95.

36. The method as claimed in any one of the preceding claims 32 to 35, wherein the contact area (11, 12, 15) has a useful region N and is used to calculate the first bond quality index Q, of the useful region N, and/or Q 1 is ascertained by Q 1= 1 - (N - G) / N.

37. The method as claimed in the preceding claim, wherein the first bond quality index Q1 is ascertained before the first and the second substrate (3, 4) are joined to one another, and/or comprising the step of ascertaining a second bond quality index Q2 of the contact area (11, 12, 15) of the hermetically tightly joined assembly (1), wherein in particular Q2 is greater than Qi, more particularly Q2/Q1>1.001 holds true.

38. The method as claimed in one of the preceding claims 32 to 37, comprising the following step: igniting a plasma discharge in the mixing zone (62) by means of a laser to prepare the laser joining operation.

39. An enclosure (9) or hermetically connected arrangement (1) produced by the method as claimed in one of the preceding claims 32 to 38.

40. The use of a hermetically connected arrangement (1) as claimed in one of claims 1 to 27 or a hermetically sealed enclosure (9) as claimed in one of claims 28 to 31 in contact with human, animal or plant cells, in particular as a medical implant, in particular as a medical intracorporeal sensor, or as a wearable.