Hermetic laser welded enclosure

Abstract

A hermetically sealed housing is shown that includes at least a first substrate and a second substrate that is at least partially and / or transparent for at least a certain wavelength band; a functional area circumferentially encapsulated in the housing; at least one laser weld line for hermetically welding the substrates of the housing to each other and / or for hermetically sealing the functional area; and at least one reduction area for reducing the amount of molecules in the functional area.

Description

[Technical field]

[0001] The present invention relates to an enclosure, for example an enclosure for providing a hermetically sealed compartment within at least two substrate layers, and a method for making the same. [Background technology]

[0002] Background and Summary of the Invention The housing can be used, for example, to protect electronic devices, circuits or sensors. Hermetically sealed implementations of the above-mentioned housings can be used, for example, in treatments for curing heart diseases, or for medical implants, for example in the retina, or for any kind of bioprocessor. Bioprocessors made of titanium are known.

[0003] Sensors can be protected by the means of the invention, for example for use in particularly harsh climatic conditions. Further examples are micro-electromechanical systems (MEMS), pressure sensors, blood gas sensors, glucose meters, e.g. blood glucose meters, etc.

[0004] Further fields of use for the invention can be found in protective sleeves for mobile phones, in the field of virtual and augmented reality goggles and helmets and similar devices. For example, the invention can also be used in the field of electromobility, but also in aerospace environments, in high temperature environments and in the field of micro-optics.

[0005] All of the above mentioned applications involve equipment that faces harsh environmental conditions and must therefore be specially designed to be robust or protected from those conditions. For example, the present invention may be used to protect such equipment, e.g. electronic equipment, to allow the use of any electronic equipment that may not be expected to survive the above mentioned environmental conditions, but which can be manufactured more cheaply or where no harsh electronic equipment exists that can withstand the conditions.

[0006] Furthermore, the invention can to some extent allow exchange or communication means with the device according to the invention, for example with the internal area of ​​the housing or with a hollow part located inside the housing. This exchange or communication means can be realized for example by electromagnetic radiation, for example in the visible light range and / or in the range of microwave radiation. To achieve that, the housing is at least partially and / or at least for a certain wavelength range transparent. This transparency allows any kind of communication method for data or energy transfer and measurement with and by electronic devices or sensors located inside the hollow part. In particular, optical communication methods or optical data or energy transfer are possible.

[0007] However, implementing a hollow section within a housing is only one embodiment of a possible application of the present invention. As will be appreciated below, the present invention is not limited to housings having hollow sections, but a preferred application is nevertheless for improving housings having hollow sections.

[0008] It is mainly known to provide several parts or layers and arrange them in such a way that components can be located in the inner area. For example, EP 3 012 059 B1 shows a method for manufacturing a transparent part for protecting an optical part. There, a new laser welding method is used.

[0009] The layers used may all be glass or glass-like substrates, but there is also increasing interest in combining different materials with one another, for example metal and glass, or epoxy resins, or other silicon-containing materials. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] European Patent No. 3012059 Summary of the Invention [Problem to be solved by the invention]

[0011] With respect to such enclosures, it is an object of the present invention to improve the long-term reliability of devices or functional areas enclosed within the enclosure.

[0012] Another object of the present invention is to provide a housing that can be designed even smaller, since in order to design the housing as small as possible, fewer or no additional layers and / or additional materials are required. [Means for solving the problem]

[0013] As background information for the present invention and at the same time to explain the motivation behind the present disclosure, it was identified during the course of the present invention that moisture in an enclosure can be problematic, at least in the long term, for devices installed inside the enclosure or when the humidity level of the environment changes. For example, a typical enclosure is assembled in a clean room, but the relative or absolute level of humidity in the air may not be regulated in the clean room. Or in other words, even if the air temperature inside the clean room, and therefore the maximum possible humidity level, can be tightly controlled, the absolute value may vary between different countries or between different factory specifications. For some components, such as OLED layers, moisture is particularly harmful.

[0014] Overall control of cleanroom humidity consumes energy and is therefore relevant to greenhouse gas control and / or sustainable energy availability. This is particularly relevant for locations with higher external temperatures and / or humidity. Thus, relatively high levels of moisture may be present in the cleanroom air during assembly, and may become trapped within the enclosure upon hermetic sealing of the enclosure.

[0015] The moisture content of HO in an air volume can typically range from about 1,000 ppm to 50,000 ppm (parts per million) of HO depending on, for example, the current precipitation conditions and temperature. For example, in air at a temperature of -20°C, the moisture content in the air volume is about 1,000 ppm, which corresponds to a water vapor pressure in air of about 100 Pa, or an absolute humidity of 0.88 g / m 3 Furthermore, in air at a temperature of +30°C, the moisture content by volume of the air is about 30,000 ppm, which corresponds to a water vapor pressure of about 4,200 Pa, or an absolute humidity of 30.4 g / m 3 However, even the relatively low moisture levels of 1,000 ppm in dry and / or very cold air may be too high for sensitive electronic equipment and / or for long term durability.

[0016] Other aspects addressed by the present disclosure may include any amount of undesirable gases, including materials such as those produced by outgassing from electronic devices, circuit boards, components and / or sensor elements sealed inside an enclosure. Such undesirable gases or materials, such as the outgassing described above, may be separated, trapped, embedded or encapsulated in a particular region (i.e., a reduction region as described below).

[0017] The present invention can therefore be seen as approaching an improvement of known housings, for example with regard to reliability and / or robustness of the housing, with regard to environmental conditions, energy reduction, and also with regard to improving the traceability and / or size of such housings.

[0018] The problem of the invention is solved by the subject matter of the independent claims. Preferred embodiments of the invention are the subject matter of the dependent claims.

[0019] The hermetically sealed enclosure according to the present invention includes at least a first substrate having an internal surface and a second substrate having an internal surface. The first substrate and the second substrate are disposed adjacent to each other such that the internal surface of the first substrate is located adjacent to the internal surface of the second substrate. In other words, the two substrates are disposed adjacent to each other, i.e., directly adjacent to each other, and the face of the internal surface of the first substrate is in contact with the face of the internal surface of the second substrate.

[0020] Typically, each substrate of the housing is comprised in a fairly planar configuration, such that the substrate's exterior surface, as well as the interior surface opposite the exterior surface, have a relatively longer dimension than the periphery between the exterior surfaces. Again, typically the interior surface of each substrate will be aligned parallel to its respective exterior surface, although there may be an angle between the plane of the interior surface and the plane of the exterior surface if certain advantages are obtained.

[0021] A stack of substrates is formed by aligning several, at least two, substrates next to each other or overlapping each other. Such a stack of substrates can then be laser welded to firmly join the substrates to each other. For example, for each two substrates, one laser weld line can be used to join the two substrates. Thus, for example, if an enclosure is to be formed using four substrates, three laser weld lines can be introduced, each laser weld line being arranged to join two adjacent substrates of the substrate stack, respectively.

[0022] At least the top substrate, e.g. the second substrate, preferably comprises at least part of its surface or volume and / or is transparent material and / or transparent for at least a certain wavelength band, e.g. in the range of 1020 nm to 1070 nm. Thus, whenever a laser is used to weld and join substrates together, the laser can pass through the second substrate to reach, e.g., the interface area between the two substrates to be welded.

[0023] The hermetically sealed housing comprises a functional area that is circumferentially enclosed within the housing. Such a functional area may for example comprise a hollow portion and / or may comprise one or more devices or components that are to be protected from environmental conditions outside the housing by being enclosed inside the housing. For example, the functional area may comprise some detection means, some microelectronic or mechanical systems and / or micro-optical components. Even energy harvesting devices, for example small solar cells, may be provided in the functional area. In other words, the hollow portion is one embodiment of the functional area, and said functional area may in one example consist of the hollow portion and some electronic components arranged inside the hollow portion. In another example, the functional area may consist of an electronics layer, for example a layer of light receiving diodes.

[0024] The hermetically sealed housing according to the present invention further comprises at least one laser weld line for hermetically welding the substrates of the housing to each other and / or hermetically sealing the functional area, for example, a first substrate can be hermetically joined to a second substrate by drawing the laser weld line tightly around the functional area.

[0025] A laser weld line typically includes a series of continuous laser dots that are positioned close enough together so that they overlap to form a continuous laser weld line. Such a continuous laser weld line created by a series of laser dots has a hermetic seal, for example when it is drawn around a functional area. The laser weld line melts or mixes the material of the first substrate with the material of the second substrate in the "convection zone," and the laser dots are positioned such that said mixture of materials is achieved, thereby firmly bonding the substrates together.

[0026] For example, at least one laser weld line can include a first separation distance S1 relative to the exterior surface of the first substrate and a second separation distance S2 relative to the exterior surface of the second substrate, and / or can be positioned such that it includes a third separation distance S3 relative to the periphery of the housing. In other words, the laser weld line can provide a reliable spacing relative to the exterior surface or periphery of the first or second substrate such that none of those boundaries of the housing interfere with the laser weld line. Such spacing can be referred to as a "tolerance zone." Typically, the housing is diced from a wafer or wafer stack, so that the additional spacing between the laser weld line and the edge can be advantageous in that the laser weld line is not affected upon dicing of the housing from the wafer stack.

[0027] A laser weld line can directly bond a first substrate and a second substrate to one another when the first substrate and the second substrate are positioned directly adjacent to one another and a laser weld line can directly bond the first substrate and the second substrate to one another when a direct laser induction welding process is used to join the two substrates to one another.

[0028] At least one laser weld line can extend from within the first substrate into the second substrate, and can permanently join the first substrate to the second substrate. This can be provided by one laser weld line introduced specifically to join two substrates, or multiple laser weld lines can be provided for joining the first substrate and the second substrate to each other, or for joining multiple substrates to their respective adjacent substrates. Thus, the laser weld line joining the first substrate and the second substrate can contain a mixture of the materials of the first substrate and the second substrate. Said mixture is established during the introduction of the laser spot, above which a convection of the materials occurs, because the materials melt and mix. In other words, in the laser weld line, the material from the first substrate can be mixed into the second substrate, or vice versa, i.e. the material from the second substrate can be mixed into the first substrate. In the laser weld line, a convection zone can be present, which is characterized in that in the convection zone the material from the first substrate is mixed with the material from the second substrate.

[0029] The laser weld line typically has a height HL in a direction perpendicular to its connection surface. The laser weld line can be located at a height HL1 inside the first substrate and at a height HL2=HL-HL1 inside the second substrate. In other words, the entire height HL of the laser weld line is located partially inside the first substrate or the second substrate, which means that there is no additional material or space between the first substrate and the second substrate. This indicates that the first substrate is directly bonded and mixed with the second substrate by the laser welding process. If the laser weld line reaches both substrates equally, i.e., HL1=HL2, a larger volumetric part of the convection area is located inside the top substrate. If the laser weld line is driven deeper into the first substrate, which is the bottom substrate, HL1 is larger than HL2. Nevertheless, the sum of HL1+HL2 is preferably HL.

[0030] The at least one laser weld seam can circumnavigate the functional area with a distance DF, which can for example correspond to less than or equal to the height HL. The distance DF can also correspond to less than or equal to twice the height HL.

[0031] The functional area is typically located on the inside of the first substrate and / or the second substrate. In the case of a housing having two substrates, the functional area may be located on the inside of the first substrate as well as on the inside of the second substrate. The functional area may include at least one hollow. The hollow may be located, for example, on the face of the first substrate and / or the second substrate, for example, the hollow may be excavated from the first substrate and / or from the second substrate, for example, by a grinding method. When three substrates are used to provide a housing, the top or bottom substrate may be a continuous substrate, where the functional area or hollow is located on the face of the middle substrate. For example, the middle substrate may include a hole that becomes the hollow when the three substrates are stacked together to form the substrate stack.

[0032] At least one functional component, for example an electronic component, a MEMS or a MOEMS, may be disposed inside the hollow portion.

[0033] The hermetically sealed enclosure according to the invention provides at least one reduction area for reducing the amount of molecules in the functional area. The molecules to be reduced in the functional area can be a gas, for example one of the gases that evaporate from electronic components in the functional area, or water, which can be present as hydrogen, in liquid form or as moisture, i.e. humidity in the functional area.

[0034] In other words, the reduction area is composed of an area facing the functional area and provides a reduction capability of the moisture level in the functional area. By way of example, molecules in the functional area, such as hydrogen, water or moisture, can be attracted to the reduction area, and the molecules in the functional area are forced to enter the reduction area and thus forced to leave the functional area. For example, the reduction area results in the introduction of an equilibrium of a lower moisture content for the functional area. Further, by way of example, the at least one reduction area can be designed to capture molecules, such as hydrogen, water or moisture, from the functional area. The at least one reduction area can be designed as a trap or net for said molecules, such that any gas or liquid amount of water present in the functional area is captured inside the reduction area upon contact with the reduction area. Thus, in other words, the at least one reduction area can also be described as hydrophilic.

[0035] Hydrophilic or hydrophobic surface properties can be described by wettability. Surface wettability can be measured by standard methods, for example the contact angle of a water drop as described in reference (DIN EN ISO 19403-1:2020-04). The contact angle is classically the angle measured through a liquid where the liquid-vapor interface meets the solid surface. Via Young's equation, the wettability of a solid surface by a liquid is quantified. A given system of solid, liquid and vapor at a given temperature and pressure has a unique equilibrium contact angle. Typically, highly wettable (hydrophilic) surfaces exhibit a significantly smaller contact angle, while less wettable (hydrophobic) surfaces exhibit a significantly higher contact angle. For the present invention, it has been found that hydrophilic surfaces are beneficial due to the self-desiccation effect.

[0036] Since the reduced area can be made or described as hydrophilic, the reduced area preferably exhibits a fairly small contact angle. Thus, the contact angle of the surface in the reduced area may be 20° or less, preferably 15° or less, more preferably 10° or less, or even 5° or less, or even 3° or less.

[0037] The absolute amount of molecules, e.g. water or moisture, present in the functional area to be reduced is constantly reduced by interaction with the reduction area. The reduction rate is therefore a function of time. In an advantageous embodiment, the overall device is designed to include a reduction area with dimensions calculated to allow the reduction area to "bind" or "capture" sufficient encapsulation components, especially moisture, to be reduced. Thanks to the hermetic seal provided by the laser bonding line, further molecules cannot penetrate the part from the outside, and a controlled setup is provided within the functional area, especially when the functional area includes or consists of a hollow space.

[0038] For example, a leak test using a gas, for example helium, can be applied to estimate the hermetic properties of the enclosure. The hermetic seal of the enclosure is determined when the leak rate of the gas, for example helium, is 10 at a pressure difference of 1 Bar between the inside and outside of the enclosure. -7 mbar x ls -1 Less than or equal to 10 -8 mbar x ls -1 Less than 1×10, more preferably -9 mbar x ls -1 This can be achieved if:

[0039] The reduction rate provided by the reduction area for the molecules to be reduced in the functional area, such as gas or water (e.g., in the form of moisture), can be 0.1% or more of the amount of molecules (gas or water, e.g., in the form of moisture) actually present in the functional area per day. The reduction rate can preferably be 0.5% or more per day, more preferably 1% or more per day, even more preferably 2% or more per day, 3% or more per day, or even 5% or more per day of the absolute amount of molecules (gas or water) present in the functional area. For example, if the reduction rate is 3% per day of the actual molecules (e.g., gas or water) present in the functional area and the initial molecular rate is 30,000 ppm, then in the first 24 hours, 900 ppm (3% of 30,000 ppm) will be reduced, while in the following 24 hours, 873 ppm (3% of the remaining 29,100 ppm) will be reduced, etc. In the same example, after 1,008 hours (42 days), the reduction area reduces 258 ppm (3% of the remaining 8,350 ppm) in a 24-hour period, and after 3,000 hours (125 days), the reduction area reduces 21 ppm (3% of the remaining 666 ppm) in a 24-hour period. In other words, the reduction rate of the molecules present in the functional area provided by the reduction area can preferably be constant over time, but the absolute amount of molecules (e.g., gas or water, the latter e.g., moisture) reduced by the reduction area decreases over time, at least until the reduction area is saturated. Thus, in further words, the reduction area is designed to provide a reduction of the molecules (e.g., gas or water) in the functional area such that the reduction rate is preferably constant over time.

[0040] If the first and / or second substrates comprise internal surfaces, each internal surface may face the other internal surface. Each internal surface may face a functional area, whereby at least one reduced area may be arranged on said internal surface of the first substrate and / or on the internal surface of the second substrate.

[0041] The reduction area can constitute at least a part of the internal surface of the first substrate and / or the second substrate. In other words, one or all of the internal surfaces of the substrates of the housing can themselves constitute a reduction area, so that for example moisture is drawn into the substrate, and the respective substrate can then be described as a moisture reservoir. When described as a reservoir, the reduction area can be provided in a fairly empty form and filled with molecules present in the functional area, for example hydrogen, water or moisture.

[0042] The reduced area may comprise a portion of the volume of the first and / or second substrate, including at least a portion of the internal surface of the first and / or second substrate, respectively. This reduced area or volume may then be described as having a sponge-like or sponge morphology, where the molecules (hydrogen, water or moisture) can enter the material of the reduced area, for example on or in the first or second substrate providing the reduced area, and the molecules (hydrogen, water or moisture) are captured within the sponge-like structure and adhere to the material inside the sponge-like structure. Again, the amount of the molecules (hydrogen, water or moisture) in the functional area is reduced as the molecules (hydrogen, water or moisture) are removed from the functional area.

[0043] In other words, by improving the hydrophilic properties, the reduced region may have an increased effective surface area. To increase the effective surface area, the reduced region may include structures that enhance its surface area compared to a simple or unstructured surface. For example, the reduced region may include nanostructures and / or microstructures. Examples of nanostructures and / or microstructures may include at least one of porous glass (e.g., SCHOTT CoralPore), micro- and nanostructured glass surfaces, or hydrophilic nanocoatings.

[0044] The reduced area may also be included as a coating on the inside of the first substrate and / or the inside of the second substrate, in other words, it is preferred that the reduced area faces the functional area, and more preferably is in direct contact with any part of the boundary of the functional area.

[0045] The reduction area may be designed to absorb said molecules (eg water vapor) from the functional area.

[0046] The reduced area and / or reduced volume, when considered as a three-dimensional reduced area, may contain unsaturated OH groups, which allow any amount of molecules (e.g. hydrogen, water or moisture) to attach to at least one unsaturated OH group, thereby saturating the respective OH group and reducing the amount of said molecules (hydrogen, water or moisture) freely circulating in the functional area.

[0047] The hermetically sealed housing may be designed such that the reduced area may be regenerated or reactivated or activated by heating the reduced area and / or the housing above a threshold temperature, which may be, for example, 50° C. or higher, or 75° C. or higher.

[0048] The reduced area may be regenerated or reactivated or activated, for example, by fire polishing, dry etching, dry cleaning or plasma cleaning. Further, by way of example, the inside of the first substrate and / or the inside of the second substrate may be regenerated or reactivated or activated by at least one of the methods described above.

[0049] Regeneration or reactivation or activation of the reduced area can increase its permeability for said molecules (hydrogen, water or moisture).

[0050] The reduced area is preferably provided and designed so that the laser weld line can pass through the reduced area without affecting its good operation.

[0051] The functional area may be circumferentially surrounded by a reduced area, where the reduced area is arranged inside at least the first and second substrates and may further be arranged inside the intermediate substrate, if applicable.

[0052] The first substrate may be in direct contact with the second substrate at least in the contact area, e.g. in a two-dimensional contact area. The first substrate may be in direct contact with the second substrate, e.g. in an area surrounding the functional area. If an intermediate substrate is provided, the first substrate is in direct contact with the intermediate substrate and the second substrate is in direct contact with the intermediate substrate. In such a case, two contact areas are provided, one between the first substrate and the intermediate substrate and the other between the second substrate and the intermediate substrate, and at least two separate laser weld lines are introduced to hermetically seal the functional area.

[0053] Advantageously, the functional area comprises at least one cavity, which may contain a quantity of gas inside the cavity space, and not only may certain gases be used, for example noble gases such as helium, but also clean room air may remain present inside the cavity.

[0054] The reduction area may be designed to reduce the content of said molecules (e.g. hydrogen, water and / or moisture) inside the functional area or inside the hollow. Such reduction of the molecular (hydrogen, water and / or moisture) content may be until establishing a molecular content of 700 ppm (parts per million) or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less. Typically, the unreduced amount of molecules (hydrogen, water and / or moisture) in the purified air may range from 1,000 ppm to 50,000 ppm.

[0055] The functional area of ​​the housing may have a content of said molecules (hydrogen, water and / or moisture) of 700 ppm or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less. Such a low fraction of molecules (hydrogen, water and / or moisture) in the functional area or hollow portion is achieved by introducing a reduction area according to the invention, it being understood that the reduction area can reduce the amount of said molecules content (hydrogen, moisture or water) in at least one of the housing, the functional area or the hollow portion.

[0056] The present disclosure also provides for the use of the above-mentioned hermetically sealed housing for manufacturing medical implants, wafer level packaged components, microlens composites, micro-optical chips, pharmaceutical packaging, sensors, such as LIDAR sensors, or LED devices, to name a few.

[0057] The present disclosure also provides a method for manufacturing a hermetically sealed housing, for example as described above, enclosing a functional area. The method includes providing a first substrate and a second substrate. It further provides for manufacturing a reduction area on or in the first substrate and / or the second substrate for reducing the amount of molecules (hydrogen, water or moisture) in the functional area. Alternatively, the method may provide for providing the reduction area on or in the first substrate and / or the second substrate. A step of aligning the first substrate inside and inside the second substrate is provided. In other words, the first substrate is placed adjacent to the second substrate, with the respective internal surfaces being placed in contact with each other.

[0058] Furthermore, the method provides for laser welding the first substrate to the second substrate by introducing at least one laser weld line into the housing, at this stage hermetically sealing the functional area.

[0059] The method described herein may further include laser welding the laser weld line by directing a laser beam from a laser beam source such that the laser weld line is drawn around the functional area and between the first substrate and the second substrate. The step may also result in directing the laser beam from the laser beam source such that it penetrates into both the first substrate and the second substrate, whereby the first substrate is securely and permanently welded to the second substrate.

[0060] The method described herein may further comprise drawing a laser weld line by a pulsed laser source such that a continuous or quasi-continuous weld line is composed of a plurality of laser pulses. Spaced laser weld lines may be generated when the laser pulses are spaced apart from the successive laser pulses. The introduction of the laser weld line hermetically seals the functional area by said laser weld line. Several laser weld lines may be drawn around a functional area, preferably including a hollow, to improve the hermeticity of the functional area.

[0061] In the step of directly aligning the at least two substrates with respect to one another, the first substrate may be in direct contact with the second substrate such that at least 25 percent of the area of ​​the inside of the first substrate is in direct contact with the inside of the second substrate. As mentioned above, the second substrate may include a material that is transparent over at least a portion of its surface or volume and / or at least for a certain wavelength range.

[0062] After the step of hermetically sealing the functional area, it may further include a step of reducing the amount of molecules (hydrogen, water or moisture) in the functional area to 700 ppm or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less.

[0063] Furthermore, a step may be provided of activating or reactivating or regenerating the reduced area.

[0064] There may be provided a step of heating the enclosure above a threshold temperature, for example above room temperature or above 50°C, preferably to a temperature of 75°C or higher.

[0065] Either the step of activating or reactivating or regenerating the reduced area or the step of heating the housing above said threshold temperature may preferably be performed after the step of hermetically sealing the functional area.

[0066] The step of directly aligning the two substrates with one another such that the first substrate is in direct contact with the second substrate may be performed such that no other material is disposed between the first substrate and the second substrate, such other material not required for the welding method described herein may include, for example, a glass frit or an adhesive, or any such additional bonding material.

[0067] The present disclosure may also provide an evacuated and sealed housing manufactured by the above-described method.

[0068] As materials for the first and / or second substrate, various materials can be used, such as homogeneous glass or single crystal silicon, chemically strengthened glass (even coated with optical coatings), glass or glass-like materials, such as glass ceramics or crystals. Furthermore, silicone-based substrates can be used, and any of the above-mentioned materials can be used in combination with each other.

[0069] A laser weld seam is typically obtained by striking the material with a short pulsed laser beam from a laser source at a defined wavelength and energy to place a series of laser beam spots in the material of the housing. By placing the beam spots close together such that the resulting nonlinear absorption regions are in contact with, or even overlap with, at least adjacent nonlinear absorption regions, a heat buildup can occur that produces a continuous weld seam.

[0070] In a direction perpendicular to the connection surface, the laser weld line has said height HL. The connection surface is the direction in which adjacent or successive beam spots are set, for example the contact surface of the internal surfaces of the first and second substrates. Typically, laser welding is performed from a "perspective from above", i.e. the substrate stack is placed, for example, on a surface, for example a table, and the laser is shot from above through at least the top substrate layer, or through one or more substrate layers, to the location of the beam focus. The height HL is therefore measured in the direction of the laser beam, and the width of the laser weld line is measured perpendicular to the direction of the laser beam. Although a top-down setup is preferred for practical reasons, the aforementioned steps of the invention can also be realised using a setup in which the focused laser beam is applied from below or to the side of the workpiece. It is clear here that directions or positions such as "from above" or "up", "down" etc. are only indicated for reasons of clarity and to make the example more symbolic, and are not meant to limit the scope of protection in any way. In contrast, the present specification is not limited to such orientation, and "from above" may, for example, be "from below," and by way of example, the substrates may be partitioned in other arrangements, and a first substrate may be above or below a second substrate, unless technically prohibited for any reason shown in each example given herein.

[0071] The present invention will now be described in more detail and in view of preferred embodiments with reference to the accompanying drawings, in which like numerals refer to like or similar components and in which: [Brief description of the drawings]

[0072] [Figure 1] FIG. 1 shows a schematic cross-sectional view of a housing according to the present invention. [Diagram 2] FIG. 2 shows a schematic cross-sectional view of a housing according to another embodiment. [Diagram 3] FIG. 3 shows a schematic top view of the housing. [Figure 4] FIG. 4 shows a schematic cross-sectional view of another embodiment of the housing. [Diagram 5]FIG. 5 shows a cross-sectional detail of the laser region of one embodiment of the housing. [Figure 6] FIG. 6 shows a schematic diagram of a cross section of the laser spot area in the housing. [Figure 7] FIG. 7 shows an embodiment of a method for manufacturing a housing according to the present invention. [Figure 8] FIG. 8 shows another embodiment of the method for manufacturing the housing. [Figure 9] Figure 9 shows a photograph of part of the housing. [Figure 10] Figure 10 shows a photograph of several enclosures. [Figure 11] Figure 11 shows another photograph of multiple housings. [Figure 12] FIG. 12 shows graphical data of inside enclosure drying according to the present invention. [Figure 13] FIG. 13 shows another set of graphical data illustrating drying in an enclosure according to the present invention. EXAMPLES

[0073] Detailed Description of the Invention With reference to FIG. 1, a cross-sectional view of one embodiment of the housing 1 is shown, in which the lower layer 3 is arranged under the upper layer 4. The lower layer or first substrate 3 and the upper layer or second substrate 4 are hermetically bonded to each other by three laser weld lines 6a, 6b, 6c. The three laser weld lines 6a, 6b, 6c extend into the material of the first substrate 3 as well as into the material of the second substrate 4, mixing the materials of the two substrates 3, 4. Introducing a tight seal between the substrates 3, 4, 4a, the laser weld lines 6a, 6b, 6c can provide a hermetically sealed area, where the laser weld lines 6a, 6b, 6c are drawn around this area. In this hermetically sealed area a functional area 2 is arranged, which in this example is configured as a hollow part 2. The two substrates 3, 4 are in contact with each other on the inner side 31 of the first substrate 3 and on the inner side 41 of the second substrate 4. Both inner sides 31, 41 meet each other at the contact area 15.

[0074] An edge 12 of the glass laminate, including the edge 11 of the contact area 15, connects the first substrate 3 and the second substrate 4 and runs around the housing. In the perspective view of Figure 1, the edge 12 is oriented vertically while the first substrate 3 and the second substrate 4 have a horizontal orientation. Typically the edge 12 is oriented perpendicular to the plane of the substrates 3, 4.

[0075] A reduction area 7 is arranged on the inside 41 of the second substrate 4 and facing the hollow portion 2. The reduction area 7 may already be activated or may be activated after the completion of the housing 1, for example by heating the housing 1 above a threshold temperature. The edge 12 may connect the outside of the second substrate 4 with the outside of the first substrate 3 over the edge 11, so that the entire external surface of the housing 1 may be constituted by the outside of the second substrate 4, the edge 12 and the outside of the first substrate 3. In this embodiment, the component 5 is arranged in the hollow portion 2, where the component 5 cannot be heated above a temperature that may damage the component 5. Therefore, the housing cannot be heated without restrictions in order to protect the component 5 from heat.

[0076] With reference to Fig. 2, an embodiment of the housing 1 is shown in which, in addition to the reduced area 7 shown in Fig. 1, a second reduced area 7a is provided in the lower part of the hollow part 2. Here again, the hollow part 2 is hermetically sealed by three laser weld lines 6a, 6b and 6c. Although one laser weld line 6a may be sufficient to provide a hermetic seal of the hollow part 2 inside the housing 1, by introducing several laser weld lines 6a, 6b and 6c, the hermeticity or impermeability of the hollow part 2 can be ensured. Fig. 3 shows an embodiment of the housing in a perspective view from above, in which the laser weld lines 6a, 6b and 6c are provided circumferentially around the hollow part 2.

[0077] Now referring to FIG. 4, an enclosure 1 is shown having a hollow section 2 that is hermetically sealed by laser weld lines 6a and 6b. The laser weld line 6a is drawn at the contact area 15 between the second substrate 4 and the intermediate substrate 4a, while the second laser weld line 6b is drawn at the second contact area 15a between the intermediate substrate 4a and the first substrate 3. Both laser weld lines 6a, 6b go around the hollow section 2 and hermetically seal said hollow section 2. The first substrate 3 comprises a reduced area 7a located over the entire surface area of ​​the first substrate 3. In other words, the first substrate 3 provides a reducing capacity over the entire surface 7a. The second substrate 4 in this embodiment provides a further reduced area 7b over its entire surface. For example, the second substrate 4 is a reduced substrate 7b, providing a reducing capacity over its entire surface 7b. For example, it may be easier to provide a substrate having reduction capability over its entire surface and weld such a substrate to the substrate stack of the housing so that, ultimately, the inner side 31 of the first substrate 3 facing the hollow portion 2 provides a reduction area 7a and the second substrate 4 provides a reduction area 7 facing the hollow portion 2.

[0078] 5 shows a detailed perspective view of one embodiment of a housing comprising three substrates 3, 4, 4a, two of each substrate being welded together by two laser weld lines 6a, 6b, 6c and 6d. The laser weld lines 6a and 6b are introduced in the contact area 15 between the second substrate 4 and the intermediate substrate 4a, while the laser weld lines 6c and 6d are introduced in the second contact area 15a between the intermediate substrate 4a and the first substrate 3. A reduced area 7 is provided in each contact area 15, 15a facing the interior area of ​​the housing 1 (only partially shown in FIG. 5). The laser weld lines 6a and 6b comprise a separation distance S2 relative to the outer surface of the second substrate 4 and a third separation distance S3 relative to the edge 11. The laser weld lines 6c and 6d provide a first separation distance S1 relative to the outer surface of the first substrate 3 and a third separation distance S3 relative to the edge 11. In total, all the weld seams 6 a , 6 b , 6 c , 6 d are completely enclosed inside the housing 1 .

[0079] With reference to FIG. 6, a cross-sectional detail of the laser track or laser spot is shown in more detail. The laser pulse creates a nonlinear absorbing region 35, which causes a heat build-up in the direction of the laser pulse shot (upwards in the plane shown in FIG. 6). Several distinct areas can be seen in FIG. 6, and on top of the nonlinear absorbing area 35, which may correspond more or less to the laser focus and may have a size of several micrometers, an elongated bubble-like region 32 (also called "bubble" (32) due to its very characteristic shape, which is typically similar to an elongated bubble) may be formed, which is only a few micrometers wide but typically up to several tens of micrometers high. Around the bubble-like region 32, a melted region 36 is located, with a width indicated by arrow 37 and a height indicated by arrow 38, where a temperature above Tg may be reached in the glass or in the material of the respective substrate 3, 4. The material is therefore resolidified (after cooling or dissipation of heat) in the melted region 36. The melted region 36 with the contained elongated bubble 32 can usually be clearly identified, for example by optical microscopy, because its density and / or refractive index is altered relative to the surrounding material (e.g., glass) of the respective substrate. In some cases, the nonlinear absorbing area 35 may be observed as an optical defect at the bottom edge of the melted region 36.

[0080] Each laser spot, and thus each laser weld line 6a, 6b, 6c, 6d, is therefore distinguishable, for example by optical means, so that it is possible to ascertain that laser welding of the substrates has occurred. A single laser spot may also be referred to as a heated area 34.

[0081] 7, a method for manufacturing the housing 1 is shown. In step A, the wafers 3, 4 and 4a are aligned on top of each other and a component 5 (not shown) to be sealed inside is placed in each cavity 2. In step B, the wafers are brought into optical contact to provide a wafer stack 9. In the wafer stack 9 shown here, the first substrate 3 is in direct contact with the intermediate substrate 4a and the second substrate 4 is in direct contact with the intermediate substrate 4a.

[0082] In stage C, each housing 1 is laser welded with a welding focus 52 generated by a welding laser source with focusing optics 50 to introduce laser weld lines 6a, 6b, 6c, 6d in the housing 1, thereby hermetically sealing the hollows 2. This stage can therefore be called laser microbonding of the hollows or of the housing 1. In stage D, the wafer stack 9 is diced along the dicing lines 10 (singularizing the housings). In stage E, the singulated housings 1 are placed in a bath or oven 18 to be heated above a threshold temperature, for example to 85° C. Thus, in stage E, the reduced areas 7 in the housing 1 are activated or reactivated. During heating of the singulated housings 1, drying of the respective functional areas 2 and / or hollows is achieved. In this process, during heating of the housing 1, the pressure inside the hollows increases, while due to the hermetic sealing of each hollow 2, gas cannot easily escape from the hermetically sealed hollows 2. The increase in pressure in the cavity improves the absorption of said molecules, e.g. hydrogen, water or moisture, into the reaction area 7. Thus, in the embodiment shown in Fig. 7, the reduction of the amount of said molecules (water, moisture or hydrogen) in the functional area 2 (e.g. provided as hollow section 2) of the housing 1 is an active process, in which a certain temperature range is selected that is high enough to activate the reduction area 7 and increase the absorption rate of said molecular content (hydrogen, water or moisture) into the reduction area, but on the other hand is low enough not to affect or even destroy the functional components 5 located in the hollow section 2. For example, the temperature to be selected can be above 50°C, or above 75°C, e.g. 85°C, and the temperature to be selected can be below 80°C, or below 100°C, or below 120°C in order to protect the functional components 5. Heating of the enclosure 1 in the oven 18 is continued until the moisture level inside the hollow portion 2 drops to below 500 ppm, better yet below 250 ppm, and even better still below 100 ppm.

[0083] Since the first and / or second substrate 3, 4 can already be provided activated for step A, the activation of the reduction area 7 can be performed before step A as shown in FIG. 7. The activation of the surface can be performed by surface polishing, dry or wet etching, dry or wet cleaning or plasma cleaning. For example, if a freshly manufactured glass is used as material for at least one substrate 3, 4, 4a and the OH groups are not yet saturated, the surfaces of the substrates 3, 4 can be provided activated without a further activation step. Those unsaturated OH groups can provide a reduction capability and thus provide the reduction area 7 for the hollow 2. In other words, the reduction area 7 provides a fairly low contact angle, preferably 20° or less, or 10° or less, as described above.

[0084] With reference to FIG. 8, another embodiment of the method for manufacturing a plurality of housings 1 is shown, in which in step A the substrates 3, 4, 4a are aligned on top of each other. In step B, the substrates 3, 4, 4a are brought into optical contact with each other to provide a wafer stack 9. The wafer stack 9 is then placed in an oven 18 and heated to a temperature above a threshold temperature, for example 85° C. During heating of the housing in the oven 18, the reduced area 7 is activated on the inside of the substrate 3 or 4, for example hydrogen, water or moisture is absorbed by said reduced area 7 arranged on the inside of the first substrate 3 and / or the second substrate 4. In other words, the reduced area 7 can be provided in an activated state or can be activated before establishing the hermetic seal of the provided functional area 2 by introducing at least one laser weld line.

[0085] In step D, the housings 1 are laser welded by means of laser welding focus 52 provided by a laser source using laser optics 50, thereby hermetically sealing each hollow portion 2 of the respective housing 1. In step E, laser dicing of the wafer is performed along dicing lines 10. Advantageously, the same laser generator 50 can be used as that used for the laser welding of the housings. Step F provides a hermetically sealed and dried housing 1.

[0086] 9, the effect of activating the reduced region is illustrated by placing water droplets on different areas of the reduced region 7. As can be seen, the two water droplets on the left are not attracted by the surface on which they are placed. They have a fairly hydrophobic behaviour as they are provided on a surface area of ​​the reduced region 7 that is not activated. In contrast, the droplet 22 on the right has been provided on an activated area of ​​the reduced region 7 and it can be seen that the surface exhibits a fairly hydrophilic behaviour.

[0087] 10 and 11, there are shown two samples of a wafer including multiple enclosures, where reduced areas 7 have been provided and the wafer stack 9 is about to undergo a drying step to reduce the moisture content of the enclosures 1. Figure 10 shows an enclosure 1 made from MEMPAX wafers, and Figure 11 shows an enclosure 1 made from BF33 wafers.

[0088] Figure 12 illustrates the effect of drying the wafer 9 shown in Figure 10, where the initial moisture level was found to be about 30,000 ppm and after 3,000 hours of drying a residual moisture level of about 300 ppm was achieved. Figure 13 illustrates the effect of drying obtained with the wafer 9 shown in Figure 11, where the initial moisture level started from about 10,000 ppm and after 3,000 hours of drying a residual moisture level of about 100 ppm could be achieved. This proves the effect and usefulness of the novel reduction area 7 provided on the inside of the housing 1, in particular and preferably on at least one of the insides of the first substrate 3 and / or the second substrate 4 facing the hollow portion 2. This arrangement results in a significantly larger area of ​​the reduction area 7 to be contacted with the hollow portion 2, so that the reduction effect is increased.

[0089] It is understood that the features defined in this application according to any aspect of the invention or in relation to any particular embodiment of the invention can be used alone or in combination with any other features of the aspects or embodiments of the invention. In particular, the invention is intended to protect the housing 1 and / or the method of manufacturing the housing 1 configured to include any feature described in this application. It is generally understood that any feature disclosed in this application, whether or not it is disclosed in the specification, claims and / or drawings, can be an essential feature of the invention alone, even if it is disclosed in combination with other features.

[0090] It will be further understood that the above-described embodiments of the invention are merely illustrative and illustrative of the principles thereof, and that further modifications and variations can be made therein without departing from the scope of the invention. [Explanation of symbols]

[0091] 1 Case 2 Functional area, e.g. hollow space 3 First Board 4 Second Board 4a Further substrate, e.g. intermediate substrate 5 Functional parts 6a First laser welding line 6b Second laser weld line 6c Third laser weld line 6d 4th laser welding line 7 Reduction Area 7a, 7b Further reduction area 9 Wafer stack 10 Dicing Line 11 Glass laminate / enclosure edge 12 Edge 15 Contact Area 15a Second Contact Area 18 Oven 22 Water droplets provided on the activated (hydrophilic) reduction area 7 22a Water droplet provided on non-activated (hydrophobic) reduced area 7 31 Inside of the first substrate 32 Long and thin bubbles 34 Heating area 35 Nonlinear absorption area 36 Molten Zone 37 Laser weld line width 38 Vertical height of laser weld line 41 Inside of the second board 50 Laser source with focusing optics 52 Welding laser focus S1 Separation distance to the outer surface of the first substrate 3 S2 separation distance to the outer surface of the second substrate 4 S3 Separation distance to edge 12

Claims

1. A hermetically sealed housing (1), comprising: at least a first substrate (3) and a second substrate (4) that is at least partially and / or at least in a certain wavelength band transparent; a functional region (2) encapsulated in the circumferential direction of the housing; at least one laser weld line (6a, 6b, 6c, 6d) for hermetically welding the substrates of the housing to each other and / or for hermetically sealing the functional region; at least one reduction region (7, 7a, 7b) for reducing the amount of molecules, such as gas or water, in the functional region (2). The hermetically sealed housing (1) as described above.

2. Further comprising the inner surface (31) of the first substrate (3) and / or the inner surface (41) of the second substrate (4), each facing the functional region (2), wherein the reduction region (7, 7a, 7b) is arranged on the inner surface of the first substrate and / or the second substrate and / or the reduction region (7, 7a, 7b) constitutes at least a part of the inner surface of the first substrate and / or the second substrate and / or the reduction region (7, 7a, 7b) includes a part of the volume of the first substrate and / or the second substrate that includes at least a part of the inner surface of the first substrate and / or the second substrate. The hermetically sealed housing (1) according to Claim 1.

3. The reduction region (7, 7a, 7b) is included as a coating on the inside of the first substrate and / or the second substrate and / or the reduction region (7, 7a, 7b) has an increased effective surface area. The hermetically sealed housing (1) according to Claim 1.

4. The hermetically sealed housing (1) according to Claim 3, wherein the reduction region (7, 7a, 7b) includes at least one of a nanostructure and / or a microstructure, porous glass, a microstructured and nanostructured glass surface, or a hydrophilic nanocoating.

5. The reduction region (7, 7a, 7b) is designed to absorb water vapor from the functional region (2) and / or the reduction region (7, 7a, 7b) contains unsaturated OH groups and / or the reduction region (7, 7a, 7b) provides a contact angle of 20° or less, preferably 10° or less. The hermetically sealed housing (1) according to Claim 1.

6. The reduction regions (7, 7a, 7b) are designed to continuously reduce the amount of molecules, such as gas, hydrogen, water or moisture, in the functional regions, and / or the reduction regions (7, 7a, 7b) provide a reduction rate of 0.5% or more per day, preferably 2% or more per day, The hermetically sealed housing (1) according to claim 1.

7. The hermetically sealed housing (1) according to claim 1, wherein the reduction regions (7, 7a, 7b) are designed to be regenerated or reactivated or activated by heating the reduction region and / or the housing above a threshold temperature, such as 50 °C or more or 75 °C or more.

8. The reduction regions (7, 7a, 7b) are regenerated or reactivated or activated, for example, by at least one of the inner sides (31, 41) of the first substrate and / or the second substrate (3, 4), such as flame polishing, dry or wet etching, dry or wet cleaning, or plasma cleaning, and / or the regeneration or reactivation or activation of the reduction regions (7, 7a, 7b) increases its permeability for the molecules, and / or the reduction regions (7, 7a, 7b) are designed such that the laser weld lines (6a, 6b, 6c, 6d) can penetrate the reduction regions. The hermetically sealed housing (1) according to claim 1.

9. The laser weld lines (6a, 6b, 6c, 6d) include a continuous series of laser dots, and / or the laser weld lines (6a, 6b, 6c, 6d) directly bond the first substrate (3) and the second substrate (4) to each other by a direct laser-induced welding process, and / or in the laser weld lines (6a, 6b, 6c, 6d), the material from the first substrate (3) is mixed into the second substrate (4), and / or the material from the second substrate (4) is mixed into the first substrate (3), and / or in the laser weld lines (6a, 6b, 6c, 6d), a convection region (36) exists where the material from the first substrate (3) is mixed with the material from the second substrate (4). The hermetically sealed housing (1) according to claim 1.

10. The laser weld lines (6a, 6b, 6c, 6d) reach into both the first substrate (3) and the second substrate (4), and / or The laser weld lines (6a, 6b, 6c, 6d) contain a mixture of the materials of the first substrate (3) and the second substrate (4), and / or the laser weld lines (6a, 6b, 6c, 6d) have a height HL in a direction perpendicular to their connection surfaces, and the laser weld lines are located at a height HL1 inside the first substrate (3) and a height HL2 = HL - HL1 inside the second substrate (4). The hermetically sealed housing (1) according to claim 1.

11. The functional region (2) is circumferentially surrounded by reduction regions (7, 7a, 7b) arranged inside the first substrate (3) and the second substrate (4) (31, 41), and / or the functional region (2) includes at least one hollow portion, and at least one functional component (5), such as an electronic component, MEMS or MOEMS, is arranged inside the hollow portion. The hermetically sealed housing (1) according to claim 1.

12. The first substrate (3) is in direct contact with the second substrate (4) in at least the contact areas (15, 15a), for example, in a two-dimensional contact area. The hermetically sealed housing (1) according to claim 1.

13. The reduction regions (7, 7a, 7b) are designed to reduce the molecular content, such as the content of hydrogen, water and / or moisture, to 700 ppm or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less, and / or the functional region (2) of the housing has a molecular content, such as the content of hydrogen, water and / or moisture, of 700 ppm or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less. The hermetically sealed housing (1) according to claim 1.

14. Use of the hermetically sealed housing (1) according to any one of claims 1 to 13 for manufacturing a medical implant, a wafer-level package component, a micro-lens composite, a micro-optical chip, a pharmaceutical package, a sensor, such as a LIDAR sensor, or an LED device.

15. A method for manufacturing a hermetically sealed housing (1) enclosing a functional region (2), such as the hermetically sealed housing (1) according to any one of claims 1 to 13, comprising the following steps:[[]] Providing a first substrate (3) and a second substrate (4). Producing or providing a reduction region (7, 7a, 7b) on or in the first substrate and / or the second substrate for reducing the amount of molecules in the functional region, such as hydrogen, water or moisture. Aligning the first substrate inside (31) with the inside (41) of the second substrate. Hermetically sealing the functional region by introducing at least one laser welding line (6a, 6b, 6c, 6d) into the housing. The method as described above, including the above steps.

16. The step of hermetically sealing the functional region (2) comprises guiding a laser beam (52) from a laser light source (50) such that the laser welding lines (6a, 6b, 6c, 6d) are drawn around the functional region and between the first substrate (3) and the second substrate (4), and / or such that it reaches into both the first substrate and the second substrate. The method for manufacturing a hermetically sealed housing (1) according to claim 15, including the above steps.

17. The method for manufacturing a hermetically sealed housing (1) according to claim 15, wherein the laser welding lines (6a, 6b, 6c, 6d) are drawn by a pulsed laser source (50) such that the continuous or pseudo - continuous welding lines are composed of a plurality of laser pulses.

18. After the step of hermetically sealing the functional region (2), reducing the amount of molecules in the functional region to an amount of 700 ppm or less, preferably 500 ppm or less, more preferably 250 ppm or less, or even 100 ppm or less. The method for manufacturing a hermetically sealed housing (1) according to claim 15, further including the above step.

19. Activating or re - activating or regenerating the reduction region (7, 7a, 7b), and / or heating the housing to a temperature above a threshold temperature, such as above room temperature, or above 50°C, preferably above 75°C. The method for manufacturing a hermetically sealed housing (1) according to claim 15, further including the above steps, and any of the above steps is preferably carried out after the step of hermetically sealing the functional region.

20. The aligning step directly aligning two substrates (3, 4, 4a) such that the first substrate (3) is in direct contact with the second substrate (4), for example establishing contact without a gap between the first substrate and the second substrate and / or without other materials being disposed between the first substrate and the second substrate, A method of manufacturing a hermetically sealed housing (1) according to claim 15. Claim 21 The step of hermetically sealing the functional region by introducing at least one laser weld line (6a, 6b, 6c, 6d) into the housing is carried out in a moisture-containing atmosphere and / or in a clean room having a moisture content of H 2 O molecules in the ambient air in the range of at least about 1,000 ppm to 50,000 ppm, a method for manufacturing the hermetically sealed housing (1) according to claim 15. Claim 22 An evacuated and sealed housing (1) manufactured by the method according to claim 15.

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