Hermetically sealed glass enclosure

Description

Field of invention

[0001] The invention relates in particular to a hermetically sealed glass enclosure, in particular multiple times, and to a method for providing a hermetically sealed glass enclosure. Background and general description of the invention

[0002] Hermetically sealed enclosures can be used, for example, to protect sensitive electronics, circuits, or sensors. This allows for the use of medical implants, such as those in the heart, retina, or for bioprocessors. Bioprocessors made of titanium are known to exist.

[0003] Sensors can be protected against particularly harsh environmental conditions with an enclosure according to the invention. Examples of such sensors include MEMS (micro-electro-mechanical systems), barometers, blood gas sensors, glucose sensors, etc.

[0004] Another field of application for an enclosure according to the invention can be found in a case for a smartphone, in the field of virtual reality glasses and similar devices. An enclosure according to the invention can also be used for the production of flow cells, e.g., in the context of electromobility. But enclosures according to the invention can also be used in aerospace, in high-temperature applications and in the field of micro-optics.

[0005] The aforementioned applications have in common that high demands are placed on the robustness of the electronics. To enable the use of electronics that are not expected to withstand these external influences, the housing must be protected from such adverse environmental conditions. Furthermore, it may be necessary to ensure communication with the interior of the housing, i.e., the cavity formed by the housing, for example, with electromagnetic radiation, particularly in the visible and / or microwave ranges. This means the housing must be at least partially transparent – ​​i.e., at least in certain areas and / or for a specific wavelength range. This transparency allows for communication methods, data or energy transmission, and measurements of and with the electronics or sensors located in the cavity. Optical communication methods, in particular, can be used.optical data or energy transmission may be possible.

[0006] It is generally known to join several parts together and arrange them in such a way that a receiving area is created in the space between them, in which components can be housed. For example, EP 3 012 059 B1 discloses a method for manufacturing a transparent part for protecting an optical component, which is incorporated by reference. A novel laser process is used in this process. WO 2012 / 087369 A1 discloses a housing consisting of a base substrate and a top substrate, which are hermetically bonded using a laser bonding line. This document also discloses a corresponding manufacturing process.

[0007] Problems can arise when a significant amount of heat energy is released from the interior of the casing, whether over a short or extended period, for example, in the case of its use as a bioimplant, as the heat escaping from the casing could potentially damage the surrounding tissue. Studies already exist that address the influence of heat on various tissue types, typically assuming that local damage occurs when a local temperature exceeds 43 degrees Celsius, which, depending on the location of the damage, can even lead to cell death. For example, in the event of a malfunction such as a short circuit in a semiconductor component or battery, temperatures exceeding 100 degrees Celsius can be reached within a short time. The invention is specified in the independent claims.

[0008] The present invention relates to the improvement and, in particular, the increased durability of enclosures. In other words, the invention aims to provide an improved enclosure that reduces temperature stress on the environment, thereby preventing, for example, cell damage.

[0009] This can be achieved by reducing, delaying, or influencing the heat transfer from the enclosure to the environment. If necessary, the protective effect of the enclosure according to the invention allows the use of more cost-effective components within the enclosure. In particular, components with a higher fault tolerance can be used, which are less expensive to manufacture, since the invention makes it possible to tolerate a component failure if it no longer leads to a temperature spike, especially in the fabric.

[0010] Another aspect of the present invention is based on the recognition that, in the case of a hermetically sealed housing solution, special precautions may be necessary to dissipate any heat that may be generated in the housing, particularly from power semiconductors, over a longer period of time.

[0011] An enclosure according to the invention is therefore designed for the thermal encapsulation of a functional area. In other words, the enclosure is thermally insulating, such that heat is prevented from escaping the enclosure into the environment, particularly heat spikes that can occur, for example, when an electronic component within the enclosure fails. For this purpose, the enclosure comprises at least a base substrate and a cover substrate, the base substrate together with the cover substrate forming at least part of the enclosure or the enclosure itself. Furthermore, at least one hermetically sealed functional area, in particular a cavity, is arranged within the enclosure.

[0012] The enclosure has at least one laser bonding line, such that the substrates of the enclosure are hermetically sealed together by means of this at least one laser bonding line. Each laser bonding line has a height HL perpendicular to its bonding plane. Preferably, the laser bonding line extends with height HL into the material of the substrate located above the laser bonding line. Opposite, the laser bonding line extends into the material of the substrate located below the laser bonding line. For example, the cover substrate is fused to the base substrate by melting. In other words, during the joining step, or rather in the laser bonding line, material of one substrate mixes with material of the other substrate by melting, creating the solid and inseparable hermetic bond between the two substrates.

[0013] In an example according to the invention, at least one intermediate substrate is arranged between the base substrate and the cover substrate, wherein in this example the base substrate is joined to the intermediate substrate in a first connection plane by means of at least one first laser bonding line and wherein the cover substrate is joined to the intermediate substrate in a second connection plane by means of at least one second laser bonding line.

[0014] Heat can be generated in the functional area of ​​the enclosure, for example by placing a power electronics component there which produces heat during its operation, or if a component failure of an electronic component in the enclosure occurs, which is accompanied by a thermal spike.

[0015] Such a thermal peak load, meaning a high thermal energy load in a short period of time, can lead to a localized or area-wide increase in temperature in the vicinity of the enclosure, provided the enclosure dissipates the heat unhindered. If the enclosure is located within a body, for example, within tissue, this elevated temperature can potentially lead to cell damage and even cell death. It is generally accepted that, for instance, in the case of human tissue, cell damage and cell death can occur above a threshold temperature of 43 degrees Celsius (see, for example, "Thresholds for thermal damage to normal tissues: an update," by P. Yarmolenko et al., Int. J. Hyperthermia 2011, pp. 320–343).

[0016] On the other hand, if a power semiconductor fails, a local temperature can be reached within the semiconductor component that far exceeds 100 degrees Celsius and can even surpass the semiconductor's melting point. In this example of a defective semiconductor component, intended for use as a bio-implant in human tissue, to protect the tissue from cell damage, the housing can be designed, for instance, to dissipate the generated heat to the surrounding tissue over a longer period, thus reducing the peak temperature to such an extent that the critical temperature of 43 degrees Celsius is not exceeded.

[0017] In the most general case, this can be achieved by designing at least the base substrate and / or the cover substrate as a thermal insulator, so that the heat generated inside the enclosure is not released to the environment or is released considerably more slowly.

[0018] The enclosure includes at least one intermediate substrate. One or more functional areas can be arranged on the intermediate substrate.

[0019] The base substrate, the one or more intermediate substrates and the cover substrate can all be designed as a thermal insulator, so that preferably the entire outer shell of the enclosure acts as a thermal insulator.

[0020] At least the base substrate and / or the cover substrate is designed as a thermal insulator and consists of a material comprising a glass-like material, glass, glass-ceramic, or a combination of the aforementioned materials. Glass and glass-like materials, in particular, have proven especially advantageous because they are highly biocompatible, chemically compatible with the human body, have no known interactions with the human organism, and simultaneously provide excellent insulating properties. Furthermore, glass can be made transparent to radiation, thus enabling, for example, wireless information exchange via radiation or wave information, or contactless charging of electronics or batteries that may be located within the enclosure.If the substrate – especially the covering substrate – is transparent in the optical wavelength range, for example, an optically transparent substrate, energy can be supplied to the enclosure optically, for example, by means of a photovoltaic cell or another type of optical receptor arranged in the enclosure to provide electrical energy. The enclosure can then be described as a self-contained enclosure.

[0021] To create a hermetic seal, particularly around the functional area, one of the laser bonding lines can encircle the functional area at a distance DF. In one example, the distance DF is constant around the functional area, so the laser bonding line is located at approximately the same distance around the functional area on all sides. However, the distance DF can also vary depending on the application. This can be advantageous from a production standpoint when multiple enclosures are joined simultaneously in a single operation, and, for example, straight joining lines or laser bonding lines are applied to the respective contact surfaces of the individual enclosures. This can also be the case if the functional area or the enclosure is round or has any other shape, and the laser bonding line that hermetically seals the functional area is drawn in straight lines.In a particular example, the functional area can be designed as a cavity, and the cavity in turn can have optical properties, for example, be shaped in the form of a lens, such as a converging lens, and the laser bond line can be drawn around the cavity in a different pattern.

[0022] The functional area of ​​the enclosure is designed, for example, to accommodate at least one housing object, such as an electronic circuit, a sensor, or MEMS, so that at least one housing object is arranged within the enclosure. This housing object can comprise a power semiconductor chip, e.g., a GaN LED, or a SiC, GaAs, or GaN power transistor.

[0023] The housing object is preferably arranged in a cavity that is completely enclosed by the casing. The functional area or cavity can be incorporated into the base substrate, for example, by abrasively hollowing out a depression in the base substrate, thus surrounding the functional area and / or at least one housing object on the bottom and sides with the base substrate material. Alternatively, the functional area or cavity can be located above the base substrate. The cavity has a bottom, a lateral rim, and a top. The top can be described as a first side, the bottom as a second side opposite the first, and the rim as the intermediate area between the first and second sides, with the rim typically being substantially perpendicular to the first and / or second side.The edge can also have a height of 0, so that the top side lies directly on the bottom side, for example when the functional area only has a thin functional layer.

[0024] The enclosure comprises at least two cavities, specifically designed to house at least one component in each cavity. In other words, the components within an enclosure can be distributed across different cavities, resulting in spatial separation of the components within the same enclosure. For example, this allows a battery or storage cell to be housed separately from other components within the enclosure. This improves the protection against damage or destruction of other components by the heat generated in the event of a component failure. For instance, if a power transistor overheats, the battery or storage cell can be protected from overheating and releasing heat. Overall, this results in less heat accumulation.released into the environment, and in particular, this also keeps the overall temperature of the housing lower, so that in the case of a bio-implant, cell damage can be reduced or avoided.

[0025] Reducing heat loss from the enclosure to the environment can be improved by distributing components or housing objects across different cavities. This prevents, for example, "chain reactions" where a first component failure would cause further components to fail and release additional heat. Another benefit is that distributing the housing objects across different cavities also provides additional protection for the individual components. For instance, a storage component can be placed in its own cavity, allowing it to be safely read or removed even if a component within the enclosure fails, such as a power transistor.

[0026] Furthermore, an insulating medium can be introduced into one or more cavities, either alternatively or cumulatively, to improve the insulating effect. In other words, an insulating medium other than glass is filled into the cavity. This insulating medium is, in particular, a fluid, for example, a thermally insulating liquid or an insulating gas. The term "insulating medium" also refers to the fact that the cavity or cavities are evacuated, i.e., "filled with a vacuum," as a vacuum is also well-suited as an insulating medium. Due to the hermetic sealing of the cavity(ies)—particularly advantageously achieved using laser welding—it can be ensured that the filling of the cavity(ies) with insulating medium or with vacuum can be maintained permanently.

[0027] In other words, it is preferred if several accommodation objects are arranged in the enclosure, with the accommodation objects being divided among different cavities.

[0028] The hermetically sealed enclosure features glass feedthroughs (vias) in the intermediate substrate separating at least two cavities. These glass feedthroughs are designed for the electrical connection of the housing units located in different cavities. The glass feedthroughs are "through glass vias" (TGVs), filled with electrically conductive material.

[0029] The enclosure can have at least one electrical connection layer on at least one of the intermediate substrates. This makes it particularly easy to arrange the components or housing objects in the respective cavity and connect them electrically. The electrical connection layer is, for example, located on the underside of one, more, or all of the cavities and is in contact with the glass feedthrough(s).

[0030] While it is a preferred design for the enclosure to have a cavity in which, in particular, one or more components can be arranged, the enclosure according to the invention is not limited to the cavity design. Rather, a functional area can have or perform a function without necessarily having a cavity in the sense of a hollow space. An example of such a functional area is the application of an electrical interconnect layer to a substrate, which already forms a functional area without a cavity. Such an electrical interconnect layer can, for example, electrically connect two other functional areas, such as two cavities.

[0031] A substrate can also comprise multiple layers, thus forming a multilayer composite. Such a multilayer composite can then be joined to the other substrate(s) as one of the layers of the enclosure using laser bonding. This can mean that the multilayer composite is prepared beforehand, for example, by applying a coating to a substrate to create a two-layer composite, and this two-layer or multilayer composite is then joined as a whole to the other layer(s) during the enclosure manufacturing process.

[0032] By using a multilayer composite in the housing, additional material properties can be added to the housing. For example, the multilayer composite can already exhibit internal stress or prestress, or a prestress direction, so that the amount of internal stress can be improved when the multilayer composite is laser-welded to at least one additional layer of the housing. For example, this can improve the housing's resistance if a pre-cured multilayer composite is used. This can result in the housing as a whole taking on the properties of a cured housing. Additionally or alternatively, the multilayer composite can have one or more coating layers, for example, a coating that might cause complications if this layer had to be joined using the laser welding process.In other words, a substrate supplied as a multilayer composite is provided as a "pack" or "stack" with layers that are already bonded together. It may include an optical coating.

[0033] A laser joining process is used to join the substrates together. This laser joining process can be controlled so precisely that only a small or negligible amount of heat enters the functional area or cavity(ies) during the joining process. The laser joining process therefore takes place virtually at room temperature; that is, the housing is joined at virtually room temperature.

[0034] The laser bonding line extends, in particular to a height HL, into the material of the substrate positioned above it. A local melting process takes place within the material along the laser bonding line, so that if the laser bonding line extends partially into a first substrate and partially into a second, the two substrates are fused together by melting. In other words, the base substrate is fused to the intermediate substrate(s) and the cover substrate by means of the laser bonding line(s) by melting.

[0035] In other words, the laser bonding line is arranged or constructed in such a way that it can bridge gaps in the hermetic seal of the enclosure, for example, by melting two components together using the laser bonding line. If the enclosure only consists of a base substrate and a cover substrate to completely enclose the functional area, the contact area between the base substrate and the cover substrate—that is, the point or area where the cover substrate and base substrate meet—is bridged or connected by the laser bonding line. As a result, the enclosure forms as if it were molded in one piece, with the joint between the components also hermetically sealed by the laser bonding line.

[0036] In other words, to provide an encapsulation, a first step involves providing a first substrate (base substrate) and at least one second substrate (cover substrate), wherein the at least one second substrate (cover substrate) comprises transparent material, i.e., is transparent at least partially or entirely for at least one wavelength range. Advantageously, several encapsulations can be manufactured together, for example, from a common starting substrate, such as wafers in a wafer stack, or only the base substrate can be provided as a wafer. The process for manufacturing an encapsulation can then be followed by the singulation of each individual encapsulation by means of a cutting or separating step.

[0037] In this process, the substrate layers, or base substrate, and the cover substrate are stacked directly and in direct contact with each other, i.e., arranged adjacent to one another. Foreign materials are preferably excluded as far as possible between the substrate layers, so that the closest possible contact between one substrate layer and the adjacent substrate layer is achieved. In the case of two substrates, for example, the base substrate is arranged in direct contact with the cover substrate, specifically without any other materials or a gap between the base substrate and the cover substrate. In the case of more than two substrates, the base substrate is arranged directly adjacent to the first of the intermediate substrate layers, and the cover substrate is arranged directly adjacent to the last of the intermediate substrate layers.

[0038] The substrates are then joined together using the new laser bonding process. In this process, a planar substrate layer is directly bonded to the immediately adjacent planar substrate layer, without the need for any foreign materials, non-planar materials, or intermediate layers. The substrates are thus joined directly to each other. The laser bond line, created in the planar contact area between two substrate layers, permanently connects the directly adjacent substrate layers. The melting area of ​​the laser bond line is therefore located in both substrates and seamlessly transitions from the first substrate to the immediately adjacent second substrate, for example, from the base substrate to the cover substrate.The novel laser joining process differs from previous methods, which use lasers to join substrates, in that it introduces significantly less thermal energy into the substrate stack or the housing. This results in very little thermal energy dissipating into the rest of the housing, and components located within the functional area experiencing only a minimal temperature increase. This is particularly significant because, in this case, at least one of the housing substrates exhibits exceptionally good thermal insulation properties. Consequently, the thermal energy applied to the housing during laser joining may remain there longer before being released into the environment. The use of thermally insulating materials for the housing, especially when components are located near a laser joining line, is therefore advantageous.This is therefore only possible with the present, novel laser joining process in this combination.

[0039] This results in a direct, planar, or even full-surface transition from one substrate layer to the next, such as a substrate-to-substrate or glass-to-glass transition. A locally confined volume forms as the bonding zone or laser bond line, in which material transfer or mixing occurs between the adjacent substrate layers, which are particularly planar. In other words, material from the first substrate, for example, the cover substrate, penetrates the adjacent substrate, for example, the intermediate or base substrate, and vice versa; material from the adjacent substrate penetrates the first substrate, so that complete mixing of the adjacent substrates occurs within the bonding zone. The bonding zone can therefore also be referred to as a convection zone.

[0040] The new laser joining technology for creating permanent glass-to-glass or substrate-to-substrate bonds is particularly advantageous because it eliminates the need for intermediate layers, glass frits, films, or adhesives that were previously required between the substrates. Instead, the permanent bond can be created without any interfering intermediate layers or additional materials. This eliminates the need for additional materials, increases the achievable hardness of the final product, and enables a reliable hermetic seal of the functional area or cavity(ies). The laser joining zone can be detected in the finished product, for example, by the specific local change in the refractive index of the material within the small, localized fusion area.

[0041] In an advantageous further development, a marker may be incorporated into at least one of the substrates.

[0042] The housing is preferably at least partially and / or regionally transparent for a specific wavelength range. In a simple example, the housing's cover substrate is optically transparent, i.e., see-through, in the visible wavelength range. However, transparency in the X-ray range, for example, can also be advantageous. In other words, the cover substrate preferably comprises a glass-like material. The cover substrate is thus preferably transparent or permeable for at least one wavelength range, for example, optically transparent. Depending on the application, it can also be advantageous if the cap is opaque, i.e., optically non-transparent, like frosted glass. Reduced transparency or partial permeability may also be sufficient for the intended function.According to the invention, at least one base substrate or cover substrate consists of a material comprising a glass-like material, which comprises glass, glass-ceramic, or a combination of the aforementioned materials. In a preferred embodiment, the cover substrate is a glass plate, for example, made of tempered glass, special glass, or high-temperature-resistant glass, for example, from the applicant's product portfolio.

[0043] The enclosure can be designed such that at least one functional area of ​​the enclosure can be configured to accommodate at least one housing object measuring 10 mm x 10 mm or smaller, preferably 5 mm x 5 mm or smaller, more preferably 2 mm x 2 mm or smaller, or even 1 mm x 1 mm or smaller. The size of the enclosure then depends on the size and number of housing objects in the functional areas or cavities of the enclosure. For example, if one housing object measuring approximately 5 mm x 5 mm is arranged in each of four cavities of the enclosure, with two cavities arranged side by side and two cavities stacked on top of each other, the enclosure will typically have a size of 13 mm x 13 mm or larger, thus ensuring that the objects are adequately housed in the cavities.

[0044] A practical size consideration, dictated by the preferred manufacturing process but not intended as a strict size limitation, is the size of the wafers to be sliced. However, the use of wafers for manufacturing is merely an example. It is entirely possible, for instance, to use glass plates to produce the transparent casing, which can have larger dimensions than typical wafer sizes.

[0045] The invention also focuses on a method for providing a hermetically sealed enclosure, wherein a functional area, in particular a cavity, is enclosed by the enclosure.The method comprises the steps of providing at least one base substrate, at least one intermediate substrate, and a cover substrate, wherein the cover substrate is at least partially or regionally transparent for at least one wavelength range and is therefore a transparent cover substrate; arranging at least one housing object in the functional area, i.e., in particular in a cavity; arranging the cover substrate on the base substrate above the at least one housing object, wherein at least one contact surface is formed between the base substrate, the intermediate substrate, and the cover substrate; and hermetically sealing the cavities by forming at least one laser bond line on each of the contact surfaces, wherein at least one of the base substrate or cover substrate is thermally insulating.

[0046] In an example not related to the invention, the cover substrate is joined to the base substrate by means of the laser bonding line. In other words, the cover substrate is placed directly onto or into the base substrate without an intermediate layer and joined to the base substrate immediately and directly by one or more common laser bonding lines. In this case, the cover substrate and the base substrate together form the complete enclosure. In other words, no additional or further component is required to form or close the enclosure; rather, the base substrate, the at least one laser bonding line, and the cover substrate together completely and hermetically seal the functional area or cavity. On the other hand, it may be advantageous to use one or more intermediate substrates, for example, to separate several cavities from one another.

[0047] The at least two substrates, or the base substrate and the cover substrate, are arranged or attached to one another in such a way that they lie flat against each other, without any other layers, layers, or inclusions between the at least two substrates or between the base substrate, cover substrate, and any intermediate substrate. For technical reasons, minute gas inclusions between the layers in the contact area may be unavoidable, which may also result from any unevenness. For example, the amount of gas trapped in the area of ​​the flat contact surface can be further reduced by increasing the pressure, such as by pressing, or by surface treatment of the substrate layers, especially the contact surfaces, such as a grinding process. Prior evacuation is advantageous.Filling with a type of gas or liquid can also be advantageous, depending on the process parameters and materials to be used.

[0048] It is particularly preferred if any gap that may occur between the substrates is less than or equal to 5 µm thick, and more preferably less than or equal to 1 µm. Such a gap arises, for example, from tolerances in substrate manufacturing, thermal influences, or inclusions of particles such as dust. Even with such a tolerable gap, which within the scope of this invention is also considered to be immediately adjacent, it is possible to join with the laser in such a way that the joining zone has a thickness between 10 and 50 µm, thus ensuring a hermetic seal. In this case as well, the joining zone extends from the first substrate to the second substrate, which is located adjacent to the first. The joining zone is therefore introduced in the contact area between the first and second substrates and fuses the substrates directly together to form an inseparable bond.In other words, when the adjacent substrates are joined, material from both substrates is directly melted in the joining zone, and the material of the first substrate mixes with the material of the second substrate to form an inseparable, monolithic bond. The resulting enclosure thus exhibits a monolithic bond between the substrates, at least in the joining zone.

[0049] A contact surface need not be optically transparent. Furthermore, it is advantageous if the transparent substrate is opaque in the visible wavelength range. Only the substrate through which the laser passes to reach the contact surface has at least one spectral "window," allowing at least the wavelength of the laser to pass through the substrate, at least partially or at least in certain areas. The contact surface is designed such that the laser can deposition energy at it. For example, the surfaces of the two adjacent substrates can be roughened and preferably exhibit a roughness in the nanometer range. The laser is at least partially absorbed at this surface, allowing energy to be deposited there.In general, a contact surface within the meaning of this application is to be understood as a surface on which the incoming laser beam can deposit energy and thus a joining process can be carried out along the contact surface.

[0050] To form the laser bond line, a laser beam is guided around the functional area, hermetically sealing the functional area along at least one contact surface. If necessary, the laser beam can be guided around the area multiple times and / or multiple laser bond lines can be formed.

[0051] The invention also includes the use of a housing produced according to the above-described method, with a hermetically sealed functional area or cavity enclosed therein, as a medical implant or bio-implant or as a sensor.

[0052] The invention will now be explained in more detail with reference to exemplary embodiments and the figures, whereby identical and similar elements are partially provided with the same reference numerals and the features of the different exemplary embodiments can be combined with one another. Brief description of the characters

[0053] They show: Fig. 1 Top view of an enclosure, Fig. 2 Side sectional view of an enclosure, Fig. 3 Detail view of a joining zone, Fig. 4 Side sectional view through the functional area of ​​an enclosure, Fig. 5 Side sectional view through the functional area of ​​an enclosure with two cavities, Fig. 6a-6e Example of steps in the manufacture of an enclosure, Fig. 7 and 8 Further side sectional views through the functional area of ​​two enclosures, Fig. 9 Example of further steps in the manufacture of an enclosure. Detailed description of the invention

[0054] Fig. 1Figure 1 shows a top view of an enclosure 1 with features of the invention, wherein the circumferential laser joining zone 8 surrounds the functional area 13. The functional area 13 can have different configurations. Examples of different designs of the functional area 13 can also be found in the following sections. Figures 3 to 8 , which show the sectional views and thus are able to resolve the vertical structure of functional area 13. The various designs of functional area 13 can be graphically represented in the Fig. 3 They can be combined in this way, since all views can be represented schematically in the same way.

[0055] Functional area 13 can perform various tasks; for example, it can be configured as an optical receptor or contain a technical, electromechanical, and / or electronic component 2 located within functional area 13. Several of these tasks can also be performed within functional area 13. The housing 1 is covered on the top by the upper substrate 5, such as a cap 5. The laser joining zone 8, or at least one of it, extends into this upper substrate 5.

[0056] Referring to Fig. 2 Figure 1 shows a first sectional view of a first embodiment of an enclosure 1, which has a base substrate 3 and a cover substrate 5. In other words, the enclosure 1 is composed of two layers, namely the base layer 3 and the cover layer 5. Fig. 3Furthermore, the figure shows the structure of the laser joining line 8 consisting of a series of multiple laser pulse hit areas 16, which are placed so close together that the material of the base substrate 3 and the cover substrate 5 merge seamlessly and thus hermetically seal the functional area 13 or the cavity 12 (arranged behind the laser joining line 8 in this view).

[0057] Fig. 3 Figure 1 shows a detailed view of the joining area, showing the interface zone (i.e., contact surface 25) and the laser joining zone 8. The laser joining zone 8 is located in the area of ​​contact surface 25 to join the two substrates 3 and 5 together.

[0058] Fig. 4 shows a sectional view of an embodiment of an enclosure 1 along the line C->D, as shown in Fig. 1 is shown. Fig. 4This shows a cross-section through functional area 13, 13a, which extends, for example, as a continuous cavity or void in the housing 1. In other words, the cavity extends from the base substrate 3 into the cover substrate 5 and is, for example, in the form of a recess in the base substrate 3 and / or the cover substrate 5. Functional area 13 is formed here as a recess in the cover substrate 5, and functional area 13a as a recess in the base substrate 3, for example, by means of an abrasive process such as sandblasting. In other words, the base substrate 3 has a recess 13a, and the cover substrate 5 has a recess 13 into which a housing object 2 is inserted.

[0059] For example, functional area 13a can also include an active layer, e.g., an electrically conductive layer 34. The active layer of functional area 13a can also include a photoreceptor, for example, in the form of a photovoltaic cell, so that it is configured to generate electrical power. Then the enclosure 1 can be a self-contained enclosure 1. The functional area 13 arranged above it in the area of ​​the cover substrate 5 can include the cavity 12.

[0060] The laser joining zone 8 is arranged around the functional area 13, 13a, by means of which the functional area 13, 13a is completely sealed on the sides. It is conceivable to leave open areas in the laser joining zone 8 so that the functional area 13, 13a is not completely sealed, for example, to leave open a communication channel or space for an electrical connection, which could also be used, for example, to establish fluid communication with the environment. In other words, it is possible to refrain from sealing pre-planned areas or positions with the focused laser beam 9, but instead to create a hermetic seal there using other means, such as an adhesive. Preferably, the functional area 13, 13a is completely and seamlessly sealed on all sides to ensure the hermetic seal of the functional area 13, 13a.In cavity 12, a housing object 2, for example an electronic component, is arranged above the functional area 13a, for example on the conductive layer 34.

[0061] Referring to Fig. 5 Figure 1 shows a sectional view through an enclosure 1 according to the invention in the area of ​​functional areas 13 and 13a. The enclosure 1 has five substrate layers: a base substrate 3, three intermediate substrates 4a, 4b, and 4c, and a cover substrate 5. The intermediate substrates 4a and 4c each have a cavity 12 for housing components 2. The intermediate substrate 4b has electrical connections or glass feedthroughs 32, so-called through-glass vias, so that the components of functional area 13 can be electrically connected to those arranged in functional area 13a.

[0062] Functional area 13 is designed as a cavity 12, within which a plurality of components 2 are arranged. These components 2 are in turn arranged on electrically conductive sublayers 34, which are electrically contacted by the glass feedthroughs 32. The components 2 of functional area 13 are thus separated from the components 2 located in functional area 13a by means of the intermediate layer 4b. Should a component 2 located in functional area 13, for example, develop a defect, leak a liquid, or experience thermal overheating, the components 2 located in functional area 13a are isolated from it. Potential consequential defects in other components 2 resulting from a first component defect can thus be reduced or even prevented. An insulating medium is introduced into the two cavities 12 to further improve the insulating effect.

[0063] Referring to Figs. 6a to 6e Figure 1 shows an example of the production of an enclosure 1 according to the invention. Starting with Fig. 6a First, the intermediate substrate 4b is provided, which already has glass feedthroughs 32 or into which the glass feedthroughs 32 are inserted. For economic reasons, the manufacturing process in this example is carried out such that two enclosures 1 are built up with one wafer 4b. The subsequent separation of the two enclosures 1 can be carried out, for example, by a laser cutting process along the separation line 10. Alternatively, it is also conceivable to design a common enclosure that has cavities 12 arranged next to each other, i.e., as in the example of the Figure 6eThis corresponds to the two sub-areas being separated along the dividing line 10. In this case, horizontal glass penetrations 32 (not shown) can also be provided, corresponding to the vertical glass penetrations 32 shown, for connecting the adjacent cavities 12.

[0064] With Fig. 6b Figure 1 shows how an electrical contact layer 34 is applied to the middle intermediate layer 4b on both sides in certain areas. The electrical contact layer 34 is divided into contact areas, which can be electrically contacted with one of the glass feedthroughs 32, as shown. Some contact areas 34 can also be applied without contact to glass feedthroughs 32 if this is advantageous, for example, to connect two components 2 within a cavity to each other, but not to components 2 that are arranged in another cavity 12 within the housing 1.

[0065] With Fig. 6c The application of housing objects 2 in the areas corresponding to the subsequent cavities 12 is shown, particularly on contact areas 34. The components 2 can be electrically connected to other components 2 arranged in the same cavity 12 and / or to other components 2 arranged in a different cavity 12, particularly by means of the glass feedthroughs 32. The components 2 can be contacted, for example, by soldering, welding, epoxy conductive paste, or by wire connection.

[0066] Fig. 6d This illustrates the placement of spacer wafers 4a and 4c, one above and one below the intermediate layer 4b, respectively. The spacer wafers 4a and 4c are laser-bonded to the intermediate layer 4b, i.e., a laser bond line 8 is applied to each. Fig. 6eFinally, the application of the base substrate 3 to the underside of the housing 1 and the cover substrate 5 to the top of the housing 1 is illustrated, whereby the substrates are again joined by means of laser bond lines 8.

[0067] Thus, along the contact surfaces 25, the laser joining zone 8 is created by means of the laser pulse hits 16, at which the cover substrate 5 is welded or joined to the base substrate 3.

[0068] Fig. 7Figure 1 shows an embodiment of the enclosure 1 according to the invention, comprising a first glass interlayer 4a applied to the base substrate 3, a component carrier layer 4b on which the components 2 are arranged, a further glass interlayer 4c, and a cover substrate 5. In this embodiment, the functional areas 12, 13, and 13a are arranged such that they are positioned below and above the component carrier layer 4b, respectively. Joining lines 8 are arranged around the cavities 12, ensuring that the cavities 12 are hermetically sealed on all sides. The enclosure 1 can be round or angular and can, in principle, have a free-form shape.

[0069] The housing objects 2, for example a sensor, actuator, or processor, are arranged on the underside and top side of the component carrier layer 4b, for example, by being glued or soldered there. Metal pads 34 are arranged on both sides of the housing object for electrical contact with the housing object 2. The housing object 2 is electrically contacted with other components 2 by means of contact lines 32, such as bond wires. The metal pads 34 can be metal contact surfaces. The substrates are joined directly to each other by means of laser bonding lines 8. In this case, two closed, circumferential laser bonding zones 8 were formed by guiding the laser 9 twice around the cavity along the contact surfaces 25 or along the outer edges of the cavities 12, but not along exactly identical paths.Rather, the laser 9 was guided along a laterally offset path during each revolution around the cavity 12, resulting in two adjacent laser bonding zones 8. The microbonding zones 8 in this example have dimensions of, for example, 5 µm x 10 µm or 10 µm x 50 µm.

[0070] Fig. 8Figure 1 shows an embodiment of the enclosure 1 according to the invention, wherein a cavity 12 is introduced into the intermediate substrate or the component support layer 4b. For example, the cavity 12 can be introduced into the intermediate substrate 4b by sandblasting, i.e., hollowed out of the intermediate substrate 4b, generally using an abrasive process. Chemical etching is also possible to introduce the cavity 12 into the component support layer 4b. This embodiment is advantageous because the cover substrate 5 can, for example, be designed as a simple glass plate, which is connected to the component support layer 4b by means of microbonding and laser bonding lines 8. This embodiment is also advantageous because the components arranged in the upper cavity 12, i.e., in the cavity hollowed out of the intermediate substrate 4b, are already protected by the intermediate substrate 4b during the manufacturing process. Furthermore, a substrate layer is saved.The same reference numerals indicate the same features in the figures for all embodiments.

[0071] Referring to Fig. 9 Another embodiment of the method for producing a plurality of enclosures 1 is shown. The production of the enclosures is explained, for example, using Fig. 8 are shown. It is clear to the expert that even a single enclosure 1 can be manufactured, depending on the process requirements.

[0072] In step A, a common component support substrate 4b is provided, which has a plurality of recesses 12 corresponding to the later cavities 12, and which were introduced into the component support substrate 4b, for example, by means of an abrasive process. Housing objects 2 are arranged in each of the recesses 12, for example, at provided or already attached contacts 34 (see figure). Fig. 6a-6e) soldered on. In step B, a common cover substrate 5 is applied to the component carrier substrate 4b, i.e., a separate cavity 12 is created for each recess. Several housing objects 2 can be housed in each common cavity 12.

[0073] Subsequently, the attachment of further components 2 and the creation of further cavities 12 can be provided on the underside of the component support substrate 4b, cf. Figs. 6c to 6e and 8 For this purpose, a further glass interlayer 4a would be arranged on the underside of the component support substrate 4b, and a base substrate 3 below it. This is optional in the context of this manufacturing process.

[0074] In step C, the finished substrate stack is joined using a laser, so that the respective housing cavities 12 are hermetically sealed. This involves sealing the cavities 12 on all sides along the contact surfaces 25 and introducing at least one laser bond line 8 per housing 1. For this purpose, a laser unit 15 is guided from above the cover substrate 5 across its surface, and a focused laser beam 9 is directed at the zones to be joined, particularly at the contact surfaces 25. After completion of step C of the manufacturing process, all cavities 12 are hermetically sealed. It is possible to separate the individual housings 1 after step C using a cutting process, thus obtaining individual, separate housings 1.

[0075] In step D, the components are separated from each other along separation or cutting lines 10. The same laser can be used for this as for laser joining in step C. However, a conventional cutting method can also be used if this is advantageous.

[0076] It is evident to those skilled in the art that the embodiments described above are to be understood as examples and that the invention is not limited to these, but can be varied in many ways without departing from the scope of the claims. In all figures, the same reference numerals denote the same features, so that descriptions of features that may only be mentioned in one figure, or at least not with respect to all figures, can also be applied to those figures for which the feature is not explicitly described. Reference symbol list:

[0077] 1 Hermetically sealed enclosure 2 Hosting object, functional component 3 Lower substrate, layer or wafer, base substrate or lower cover 4, 4a, 4b, 4c, 4d, 4e, 4f Intermediate layer 5 Upper substrate, layer or wafer, cover substrate or upper cover 8 Laser joining zone 9 Focused laser beam 10 Separation or cutting line 12 Hosting cavity 13 Functional area 13a Secondary functional area 14 Edge 15 Laser unit for joining and / or cutting 16 Laser pulse hit area 18 Substrate stack 21 Edge of cavity 22 Bottom of cavity 23 Top of cavity 25 Contact surface 32 Through-glass via 34 Electrical contact layer

Claims

1. An enclosure (1) for thermal encapsulation of a functional area, comprising: a base substrate (3); a cover substrate (5), the base substrate together with the cover substrate defining at least part of the enclosure or defining the enclosure; at least one functional area (12, 13, 13a) hermetically sealed by the enclosure (1), in particular a cavity; wherein the substrates of the enclosure are hermetically joined to one another by at least one laser bonding line; wherein each laser bonding line has a height (HL) perpendicular to the respective bonding plane; wherein heat can be generated inside the functional area of the enclosure; wherein at least the base substrate and / or the cover substrate is designed as a thermal insulator and is made of a material which comprises a vitreous material comprising glass or glass ceramics or a combination of the aforementioned materials; characterized by further comprising at least one intermediate substrate (4, 4a, 4b, 4c, 4d, 4e, 4f) disposed between the base substrate (3) and the cover substrate (5); and vias (32) in the intermediate substrate which separates at least two cavities (12).

2. The hermetically sealed enclosure (1) according to the preceding claim, wherein the at least one intermediate substrate (4, 4a, 4b, 4c, 4d, 4e, 4f) is made of a material of low thermal conductivity, which comprises a vitreous material comprising glass or glass ceramics or a combination of the aforementioned materials.

3. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein at least one of the laser bonding lines (8) circumferentially surrounds the functional area (12, 13, 13a) at a distance (DF) therefrom; and / or wherein the functional area (12, 13, 13a) is adapted to accommodate at least one accommodation item (2) such as an electronic circuit, a sensor, or an MEMS, so that at least one accommodation item (2) is disposed inside the enclosure (1); wherein the at least one accommodation item (2) comprises, for example, a power semiconductor chip, e.g. a GaN LED, SiC power transistor, GaAs power transistor or GaN power transistor; and / or wherein the at least one accommodation item (2) in particular forms part of the enclosure.

4. The hermetically sealed enclosure (1) according to the preceding claim, wherein the accommodation item (2) is disposed in one of the at least two cavities (12); and / or wherein the enclosure comprises a plurality of cavities (12) for accommodating at least one accommodation item in each respective cavity; and / or wherein a plurality of accommodation items (2) are disposed inside the enclosure (1), and wherein the accommodation items are distributed to different cavities (12).

5. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein an insulating medium is included in one of the at least two cavities (12) to improve the insulating effect, the insulating medium in particular being a fluid such as a thermally insulating liquid or an insulating gas, or vacuum.

6. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein the vias (32) are provided for electrically connecting the accommodation items (2) disposed in the cavities (12); and / or further comprising at least one electrical connection layer on at least one of the intermediate substrates (4, 4a, 4b, 4c, 4d, 4e, 4f, 4g); and / or wherein at least one of the substrates (3, 4, 4a, 4b, 4c, 4d, 4e, 4f, 4g, 5) is provided in the form of a multilayer composite, for example comprising one or more coating layers or pre-stressed zones, and / or for example comprising one or more substrates.

7. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein the laser bonding lines (8) having the height (HL) extend into the material of the substrate (4, 4a, 4b, 4c, 4d, 4e, 4f, 5) which is disposed above the laser bonding line, and wherein the base substrate (3), the one or more intermediate substrate(s) and the cover substrate (5) are joined together by being fused to one another; and / or wherein a marker is incorporated in at least one of the substrates (3, 4, 5).

8. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein the enclosure (1) is transparent for a range of wavelengths at least partially and / or in sections thereof.

9. The hermetically sealed enclosure (1) according to at least one of the preceding claims, wherein the at least one functional area of the enclosure is adapted for accommodating at least one accommodation item having a size of 10 mm x 10 mm or less, preferably a size of 5 mm x 5 mm or less, more preferably 2 mm x 2 mm or less, or even 1 mm x 1 mm or less.

10. A method for providing a hermetically sealed enclosure (1), the enclosure (1) enclosing a functional area (12, 13, 13a), i.e. a cavity (12), comprising the steps of: - providing a base substrate (3), at least one intermediate substrate (4, 4a, 4b, 4c, 4d, 4e, 4f) and a cover substrate (5), the cover substrate (5) being transparent for at least one range of wavelengths at least partially or in sections thereof and thus constituting a transparent cover substrate; - arranging at least one accommodation item (2) inside the cavity; - arranging the cover substrate (5) on the base substrate (3) above the at least one accommodation item (2) thereby creating at least one respective contact area (25) between the base substrate (3), the intermediate substrate (4, 4a, 4b, 4c, 4d, 4e, 4f) and the cover substrate (5); - hermetically sealing the cavities by forming at least one respective laser bonding line (8) along the contact areas; wherein at least one of the base substrate or the cover substrate is designed to be thermally insulating and is made of a material comprising a vitreous material which comprises glass or glass ceramics or a combination of the aforementioned materials; wherein the intermediate substrate (4, 4a, 4b, 4c, 4d, 4e, 4f) separates at least two cavities (12) and includes vias (32).

11. The method according to the preceding claim, wherein the method is used to produce an enclosure (1) according to any one of claims 1 to 9.

12. The method according to at least one of claims 10 or 11, wherein a laser beam (9) is directed circumferentially around the functional area (12, 13, 13a) to produce the laser bonding line (8), so that the functional area is hermetically sealed circumferentially along the contact area (25), wherein, optionally, the laser beam can be directed circumferentially around repeatedly and / or, optionally, a plurality of laser bonding lines (8) can be formed.

13. Use of an enclosure (1) with a hermetically sealed accommodation cavity (12) enclosed therein as produced according to the method of at least one of claims 10 to 12 as a medical implant or as a sensor.