Patent Application
20240417244
The invention is related to an enclosure, for example, for providing a hermetically sealed compartment in at least two layers of substrates, as well as a manufacturing process for making the same.
Enclosures can be used, for example, to protect electronics, circuitry or sensors. It is possible to use hermetically sealed implementations of aforementioned enclosures for medical implants, for example, in a therapy to cure a heart disease, or, for example, in a retina or for any type of bio-processor. Known are bio-processors, which are made from titan.
Sensors can be protected by means of the invention, for example, for use in particular rough climate conditions. Further examples are Micro-Electro-Mechanic-Systems (MEMS), a pressure sensor, blood gas sensor, a glucose meter, such as a blood glucose meter, or the like.
Further fields of usage for the present invention can be found in protection sleeves for cell phones, in the field of virtual reality and augmented reality goggles and headsets and similar devices. For example, the invention may also be used in the scope of electro mobility; But also in aviation and space environment, in high temperature environments and in the field of micro optics the invention might be used.
The aforementioned applications all concern devices faced with rough environmental conditions and which thus have to be designed especially robust—or protected from these conditions. For example, in order to allow for the use of any electronics, which may be expected not to survive the aforementioned environmental conditions, but which may be made cheaper or where even no rough electronics exist which could withstand in this conditions, the invention may be used to protect such devices like electronics.
Especially medical applications like implants require for the device to be uniquely identifiable, both as an anti-counterfeit measure and to enable a full documentation of the whole product life cycle.
Further, the invention may allow to some extent an exchange or way of communication with the inner region of the device according to the invention, e.g., the enclosure, or the cavity situated inside the enclosure. This exchange or way of communication can be realized, e.g., by means of electromagnetic radiation, e.g., in visible light region and/or in the region of microwave radiation. For realization of the same, the enclosure is, at least in part and/or at least for a range of wavelengths, transparent. This transparency allows for communication methods, for any kind of data or energy transmission, and for measurements with and by electronics or sensors situated inside a cavity. In particular, optical communication methods or optical data or energy transmission is possible.
However, implementing a cavity in the enclosure is only an embodiment for possible usages of the invention. As will be understood below, the invention is not limited to enclosures with cavities, but nevertheless it can be used for improving enclosures having cavities.
It is principally known to provide several parts or layers and to arrange them such that in an inner region components can be situated. For example European Patent EP 3 012 059 B1 shows a method for manufacturing a transparent component for protecting an optical component. A new laser welding method is used therein.
The layers to be used can all be glass or glass-like substrates, but it gets increasingly interesting to combine different materials with each other, like metal and glass or epoxy resin, or other silicon-containing materials.
Regarding such enclosures, it was identified as an interesting further development to render a specific enclosure identifiably, or to provide any information accessible from the outside.
Therefore, it is an object of the invention to provide such information in an enclosure, which can be extracted from the enclosure without opening the same or without the need to manipulate or even destroy the enclosure.
It is another object of the invention to enter such information into the enclosure without damaging the outer surface of the enclosure, as it has been found out that such defects or damages in the outer surface may lead to cracks or destruction or influence of light entering or leaving the cavity of the enclosure.
It is yet another object of the invention to provide such an information on a rather small space or area, so that the enclosure can be kept as small as it gets.
Therefore, the present invention may be seen in the vicinity of improving known enclosures, e.g., regarding reliability and/or robustness of enclosures regarding environmental conditions, and improving traceability and/or size of such an enclosure.
The present invention can also been employed in the context of optimizing process chains, especially on wafer and or wafer/chip level: Based on this invention, wafer level information (e.g. bad contact areas or damaged zones on the silicon chip) can be mapped to individual chips. This can be employed for binning after dicing and thus avoiding redundant inspection steps, even if the assembly is spread over several factories.
The object of the invention is achieved by subject matter of the independent claims. Preferred embodiments of the invention are subject of the dependent claims.
An enclosure, according to the invention, comprises at least a first substrate having an outer surface and a second substrate having an outer surface. The first substrate and the second substrate are arranged next to each other in such a way that an inner surface of the first substrate is adjacent to an inner surface of the second substrate. In other words, the two substrates are arranged next to each other, i.e., in direct proximity to one another, wherein the inner surface plane of the first substrate is in contact with the inner surface plane of the second substrate.
Typically, each substrate of the enclosure is comprised rather flat, so that the outer surface as well as the inner surface opposing the outer surface comprise comparably longer dimensions than the circumferential rim, which lies in between the outer surfaces. By aligning several, at least two, substrates next to or above one another, a stack of substrates is formed. Such a stack of substrates may then be laser-welded in order to firmly join the substrates with each other. For example, for each two substrates, one laser weld line may be used for joining these two substrates. Therefore, for example, in the case that four substrates shall be used to form the enclosure, at least three laser weld lines may be introduced, where each laser weld line is arranged such to join the respectively two neighboring substrates of the substrate stack.
The top most substrate, e.g., the second substrate, preferably comprises transparent material and/or is transparent at least in part of its surface or volume and/or at least for a bandwidth of wavelengths. Whenever the laser is used for welding and joining the substrates to each other, the laser therefore can pass through the second substrate in order to e.g. reach the interface zone in between the two substrates to be welded. It is referred to the top-most substrate as the laser is typically shot into the substrate(s) from above. It is clear that reference is made to that substrate through which the laser has to pass in order to arrive at the laser spot where it is intended to be positioned. So in a setup where it is feasible to shoot the laser from the side or from below, then the reference to the “top-most substrate” may no longer be applicable. In any case, it is preferred, that the substrate material (substrate volume) through which the laser travels in order to place the laser spot inside the substrate/substrate stack, comprises transparent material and/or is transparent at least in part of its surface or volume and/or at least for a bandwidth of wavelengths.
The enclosure according to the invention comprises at least one laser weld zone containing an information pattern in the enclosure. The at least one laser weld zone extends from within the first substrate to within the second substrate and permanently joins the first substrate to the second substrate. So in other words, the information pattern(s) firmly join the two substrates positioned close to each other, which is, with the respective inner side in contact with the respective other inner side. The information pattern thus may also, for example, supersede usage of additional laser weld lines and provide for bonding the substrates to each other. The laser weld zone may even be designed to provide hermetical seal to a function zone situated such that it is surrounded by the laser weld zone. But on the other side, also additional laser weld line(s) may be provided to introduce, assure or improve bonding and/or hermetic seal of a function zone.
For example, the laser weld zone could comprise a first separation spacing S1 to the outer surface of the first substrate and a second separation spacing S2 to the outer surface of the second substrate. If separation spacings S1 and S2 are applied, the laser weld zone may be fully enclosed inside the enclosure. This means, in other words, that the laser weld zone is fully enclosed within the enclosure without touching or penetrating either outer surface of the first or second substrate. So to say, the laser weld zone is fully enclosed with material from either the first substrate or the second substrate, or any substrate comprised in the enclosure. The enclosure therefore fully encloses the laser weld zone, which is not in contact with the environment surrounding the enclosure. This does also mean that neither the first outer surface nor the second outer surface, which is the outer surface of the second substrate, is deteriorated by the at least one laser weld zone. This may increase mechanical and/or chemical resistance of the enclosure in comparison with enclosures, where any marking was imposed on the one of the outer sides of the enclosure.
It may also be advantageous if the laser weld zone is initially fully surrounded by material of the enclosure, e.g. including separation spacings S1 and S2, but the enclosure may, e.g. in a later process step, be thinned down so that the laser weld zone is exposed to the surrounding. E.g. the laser weld zone may then also form part of the first outer surface and/or of the second outer surface. Reference is made in this respect, and in particular with respect to methods of polishing down one of the substrates of an enclosure, to German Patent Application DE 10 2020 117 194.3, which is hereby incorporated in its entirety into the present application.
The laser weld zone can be a portion of the first substrate and/or it may be a portion of the second substrate. Preferably, the laser weld zone comprises material from the first substrate as well as material from the second substrate. In other words, material from the first substrate is melted and at the same time material from the second substrate is melted, and the materials are mixed with each other. The information pattern in the laser weld zone typically comprises a refractive index that differs from a refractive index of a normal welded portion of the first and/or second substrate. The information pattern can also be provided as a region of absorption (e.g. Black point or dot). Such a region of absorption may be caused by the shot-to-shot inter-distance/pitch, or v/R (where v is the writing velocity and R is the repetition rate of the laser pulses provided by the source). In other words, the information pattern in the laser weld zone is detectable by means of measuring the refractive index, for example, or by measuring transmission, or by visual inspection.
The information pattern of the laser weld zone may be designed to comprise the information in a certain form, such as numbers or letters. Such numbers or letters may be visually visible, so that it can be read simply by optical means, e.g., by an optical readout device, or by the human eye, maybe with the aid of augmentation means, e.g. a microscope or a macro objective. The information pattern in the laser weld zone may also comprise a binary readable information pattern, which may be a series of signs to be interpreted as zeros or ones. In an example, a broken line can be interpreted as such a binary readable information pattern. The information of the information pattern may also be given in a line length modulation, where the length of any segment of a laser weld line contains the information, or at least a part of the information to be stored in the laser weld zone. Further, the information may be stored in a barcode form or encoding, in a line width modulation, in a music sheet modulation, in a quick readout code and/or in a Morse code signal or similar. All the aforementioned forms to store the information in the information pattern of the laser weld zone can also be used in a combination, so that thickness of the laser weld lines can encode one type of information, whereas length of the laser weld line segments can encode another type of information.
The information stored in the information pattern may be made user-readable, e.g., by means of an optical readout, so that it may be readily extracted by optical means or even read by a user. The information stored in the information pattern may also be designed to be readable by means of a handheld device. The enclosure therefore may be scanned by means of the handheld device in order to extract the information from the enclosure.
It may be advantageous to encode the information in the laser weld zone in the information pattern. By means of using a codification or an encoding of the information, it may be possible to further shrink the area or space needed to provide the information in the enclosure. For example, by means of the line width modulation and depending upon the resolution of any readout tool, on a small size several types of information can be provided at the same space, where otherwise a greater space was necessary if letters or numbers would be used. Therefore, any machine-readable information may be provided typically on a smaller area and using less space in the enclosure. Thus, even the whole enclosure may be manufactured smaller.
Encoding of the information in the laser weld zone may be achieved in that a variation of the absorption-spot-distance v/R in between consecutive beam spots of a laser weld zone or laser weld line is applied, where v is the writing velocity and R the repetition rate of the laser source. The writing velocity may be realized in movement of the enclosure against a static laser source, or as the case may be, movement of the laser against a static enclosure. The repetition rate may be designed to be adjustable. By amending v/R a characteristic shape of the laser weld line/information pattern can be achieved, where data or information can be encoded to be retrievable from the enclosure.
Information in the weld line can therefore be encoded by varying the velocity v. It is also possible to vary the interspot distance by altering R. In this respect, the repetition rate is typically fixed. But e.g. by using a so-called “pulse picker” and/or by “switching off” a sequence of 1 or more pulses, also R can be altered. The pulse picker can be employed between laser source and focusing optic. It can also be integrated in the laser source, e.g. for an ultrashort laser between seed laser and amplifier.
Furthermore, an information pattern may also be obtained by altering, influencing or just considering heat accumulation of N consecutive and/or overlapping beam spots. In some form of further developing the information encoding in a variation of v/R as explained above, information encoding can also be implemented in integer multiples of N·v/R. This may be particularly interesting when high laser repetition rates are used, for example higher than 200 kHz or even in the MHz-range, where v/R is smaller or in the same order as the spot size. For example, overlapping beam spots are obtained when N is 2 or more. Preferably, N may be 10 or more, may be as high as 50 or more, preferably 100 or more, further preferably 200 or more or even 500 or more. Using MHz laser repetition rate N can get as big as N=5000. For example, N is assumed to be 20000 or less.
Therefore information encoding may be achieved in a variation of N·v/R. For example, an accumulation of sufficient N overlapping beam spots leads to a visible marking, whereas when less beam spots overlap, which is, when N is set smaller than the number of overlapping beamspots necessary for generating a visible marking, no such marking is present. This can be adjusted to generate said information pattern, for example for generating a pattern of markings and non-markings to be interpreted as “1” or “0” respectively. And also more complex shaped markings can be obtained, for example a line may be generated when the number of overlapping beam spots is held high enough to produce visible markings, a line is generated. Thereafter the number of overlapping beamspots may be reduced to a value smaller than N necessary to generate a visible marking and the line will be interrupted, or no line (marking) will be visible.
It is also possible that debris from the absorption zone gets transported to the top region of the melt region. Such “debris”-spots would also carry the longitudinal information induced by the spot-to-spot distance. So in other words, in the absorption zone the optical properties of the material may be amended such, that this material may be optically detectable and part of this material may be transported through the melting region to its top, where it rests during solidifying of the melting zone.
The information stored in enclosure may be provided redundantly. To provide redundant information, for example separate laser weld zones may be provided where, for example, two laser weld zones provide an identical information. Another embodiment, which can be combined or used separately, is to provide for a redundant information in that an information pattern is encoded by means of two different encoding means. For example, one information pattern may at the same time be encoded by line width modulation and by means of line length modulation, where retrieving the information encoded in the line width is redundant to the information retrieved from the line length. Redundancy of information can also be obtained by using an encoding method which provides for redundancy in the encoding process, for example such where the code alphabet is longer than the source alphabet, or a, preferably prefix-free, redundance-optimized encoding like e.g. Huffmann-Encoding.
The enclosure as described herein may comprise a function zone that is circumferentially enclosed in the enclosure. Such a function zone may comprise, for instance, a cavity and/or may comprise one or more devices or components to be enclosed inside the enclosure and thus be protected from the environmental conditions outside the enclosure. The function zone may also comprise some detector means, some microelectronic or mechanical system and/or any micro optics. Even an energy-harvesting device such as a small solar cell may be provided in the function zone. The function zone can consist of a coating, for example situated in between the two substrates or provided on one of the inner sides of the first or second substrate.
The laser weld zone and/or at least one laser weld line can be designed in such a way that it hermetically seals the function zone in the enclosure. For example, a laser weld line may be drawn without gap around the function zone, so that the first substrate is hermetically joined to the second substrate.
The laser weld zone and/or the laser weld line typically comprises a series of laser dots in a sequence. These laser dots may be placed close enough to each other, so that they overlap and thus form a continuous laser weld line. Such a continuous laser weld line produced by a series of laser dots comprises hermetically sealing properties, when it is drawn around the function zone. By means of the laser weld line, the substrates are firmly joined with each other in that the laser weld line melts or mixes the material of the first substrate with material of the second substrate in a “convection zone”, in that the laser dot is placed such that the aforementioned mixture of materials is achieved.
But not only the laser weld line may be arranged around said function zone. The laser weld zone comprising the information pattern may be arranged around said function zone, for example circumferentially, around the function zone.
The laser weld zone may also be arranged such that it comprises a third separation spacing S3 to the circumferential rim of the enclosure. In other words, the laser weld zone leaves a secure spacing to the circumferential rim so that also said rim is not interfered by the laser weld zone. This spacing may be called a “tolerance zone”. Typically, the enclosure is diced out of a wafer or a waferstack, so that additional spacing in between the laser weld zone and the rim is advantageous in that the information is not destroyed or interfered upon dicing the enclosure out of the waferstack.
The laser weld line directly binds the first and second substrate to each other in the case that the first substrate and the second substrate are positioned directly adjacent each other and the laser weld line is meant to join these two substrates with each other by means of a direct laser induced welding process.
The at least one laser weld zone and/or laser weld line may extend from within the first substrate to within the second substrate and may permanently join the first substrate to the second substrate. This may be provided by either a laser weld line specifically introduced to join the two substrates, or it may also be provided in the laser weld zone, where the information pattern may advantageously be hermetically joining the two substrates with each other and, additionally, provide said information pattern.
The laser weld line and/or the laser weld zone may comprise a mixture of material of the first substrate and the second substrate. The mixture is established during introduction of the laser spot, where convection of the material takes place inside the laser spot, as the material is melted and mixed.
In the laser weld zone and/or laser weld line material from the first substrate may be mixed into the second substrate and vice versa, which is, material from the second substrate may also be mixed into the first substrate.
In the laser weld zone and/or laser weld line a convection zone may be present which is characterized in that material from the first substrate is mixed with material from the second substrate in the convection zone.
The laser weld zone and/or laser weld line typically comprises a height HL in a direction perpendicular to its connecting plane. The laser weld zone and/or laser weld line may be situated with a height HL1 inside the first substrate and with a height HL2=HL−HL1 inside the second substrate. In other words, the complete laser weld line height HL is situated inside either the first substrate or the second substrate, which means that no additional material or spacing is present in between the first substrate in the second substrate. This indicates that the first substrate is directly bonded and mixed with the second substrate by means of the laser weld process. When the laser weld line is equally reaching into both substrates, HL1=HL2, but, for example, if the laser weld zone and/or laser weld line is shot deeper into the first substrate, then HL1 is greater than HL2. Still, the sum of HL1+HL2 preferably sums up to HL.
The at least one laser weld zone and/or laser weld line may circumference the function zone in a distance DF, where the distance may correspond, for example, to the height HL or less. The distance DF may also correspond to double the height HL or less.
The function zone may be arranged on the inner side of the first and/or second substrate. The function zone may also comprise at least one cavity. The cavity may, for example, be arranged in the plane of the first and/or second substrate. By way of example, the cavity may be excavated from the first substrate and/or from the second substrate, for example by means of an abrasive method. In the case that three substrates are used to provide the enclosure, the uppermost and lowermost substrate may also be continuous substrates, where the function zone or cavity is arranged in the plane of the intermediate substrate. For example, the intermediate substrate can comprise holes, which become the cavity, when the three substrates are stacked on one another.
There may at least be one functional component arranged inside the cavity, such as an electronics component, a MEMS or MOEMS.
The present disclosure also provides usage of an enclosure as described above for making a medical implant, a wafer level packaged component, a micro lens compound, a micro-optical chip, a pharmaceutical packaging, a sensor such as a LIDAR sensor, or an LED device, to give some examples.
The present disclosure also provides for a method of providing an enclosure, for example, an enclosure as described hereinabove, wherein the enclosure encloses at least a laser weld zone. The method comprises the steps providing a first substrate having an inner surface and an outer surface and a second substrate having an inner surface and an outer surface. It provides aligning the first substrate with its inner surface at the inner surface of the second substrate. In other words, the first substrate is positioned adjacent to the second substrate, and each inner surface should be in contact with each other.
It is further provided laser welding the first substrates to the second substrate by means of introducing at least one laser weld zone in the enclosure. The laser weld zone is welded such that an information pattern is provided, wherein an information is stored in the information pattern.
Moreover, the at least one laser weld zone may comprise a first separation spacing S1 to the outer surface of the first substrate and a second separation spacing S2 to the outer surface of the second substrate, so that the laser weld zone is fully enclosed inside the enclosure and/or fully surrounded by material of the enclosure.
The method as described herein may further comprise laser welding at least one of the laser weld zones by guiding a laser beam from a laser beam source such that the laser weld zone is drawn such that it reaches both into the first substrate and the second substrate, thereby firmly and permanently welding the first substrate to the second substrate.
The method as described herein may further comprise wherein the laser weld zone is drawn by means of a pulsed laser source, so that a continuous or a quasi continuous weld zone is composed from several laser pulses and/or so that spaced apart laser weld dots or patterns can be generated in the enclosure.
The enclosure as defined in the method may be enclosing a function zone and may further be comprising the step hermetically sealing the function zone by means of the laser weld line. A laser weld line may contain an information pattern and thus may be assigned to the laser weld zone. In fact, any laser weld zone may comprise any amount of laser weld lines. Only for means of better distinguishing in between the functional ability of storing information, the wording laser weld zone is used, whereas regarding providing the hermetically joining of the substrates and thus hermetically sealing the function zone, the term laser weld line is used. However, the terms laser weld zone and laser weld line may also be used interchangeable. The laser weld zone may also provide the hermetically sealing function for the function zone, for example, when a laser weld line is drawn in the laser weld zone which is a continuous laser weld line through circumferencing the function zone. The other way around, a laser weld line may be drawn such that it contains an information pattern rendering it part of the laser weld zone in that it comprises an information.
Before the step of hermetically sealing the function zone the method may further comprise the step aligning the two substrates directly at each other such that the first substrate is in direct contact with the second substrate, for example, that at least 25 percent of the area of the inner side of the first substrate is in direct contact with the inner side of the second substrate.
The second substrate may comprise at least in part of its surface or volume and/or at least for a wavelength bandwidth a transparent material.
The description may also provide for an evacuated sealed enclosure made by the method as described hereinabove.
The present disclosure also provides for a method of registering an enclosure, wherein the method comprises providing said enclosure, for example an enclosure as described hereinabove in further details. The enclosure comprises a first substrate and a second substrate and at least one information pattern, wherein said first substrate is in direct contact with the second substrate in that an inner surface of the first substrate is adjacent to an inner surface of the second substrate, and wherein said information is stored in said information pattern. The method further defines reading out said information from said information pattern, and registering said information in a data storage, wherein the information provided in the substrate allows for uniquely identifying said enclosure or several enclosures provided in a common manufacturing process.
In an aspect data can be stored directly in the enclosure, where the data may not be available or stored in another place. For example, any kind of process data of or about the manufacturing process may be directly stored in the enclosure during the manufacturing process, where actual process data such as laser properties or environmental conditions are encoded and inscribed in the enclosure. The data may, for example, be translated or encoded from an alphanumeric string to any form of inscribable encoding, such as discussed or disclosed in the present application. This information may then later be read out and registered.
In another aspect data can be stored indirectly, so that data is first or only stored in another place, such as a database, and may or may not thereafter be inscribed in the enclosure. Data may comprise process data. For example, in this case, it is possible to inscribe an unique identifier in the enclosure and to store the information such as process data in the external place, such as a database, cross-referenced by that unique identifier. For example, an alphanumeric string may be inscribed in the enclosure in encoded form, which then represents said unique identifier.
In fact, any data to be stored and mentioned throughout this application may be referred to as directly stored data, where the data itself is stored (inscribed) in the enclosure, and/or as indirectly stored data, where a unique identifier is stored in the enclosure and the data itself is stored in an external place such as a database together with or linked by the unique identifier, for example in order to register/identify/verify the enclosure.
The present disclosure further provides for a data reading and storage system for performing the method as described before, the system comprising: a data storage, a read-out device connected to the data storage by means of a transfer means to read out information stored in the information pattern of an enclosure, and computational means to process the information and to store said information in the data storage.
The present description further provides a hermetically sealed enclosure comprising at least a first substrate having an outer surface and a second substrate having an outer surface. The first substrate and the second substrate are arranged next to each other in such a way that an inner surface of the first substrate is adjacent to an inner surface of the second substrate. The second substrate is made transparent at least in part (of its volume or surface) and/or at least for a bandwidth of wavelengths. The hermetically sealed enclosure further comprises a function zone that is circumferentially enclosed in the enclosure. Further, it comprises a laser weld line for welding the first substrate to the second substrate, and wherein the laser weld line is designed such to hermetically seal the function zone in the enclosure. The hermetically sealed enclosure further comprises at least one laser weld zone to provide an information pattern in the enclosure. The at least one laser weld zone comprises a first separation spacing S1 to the outer surface of the first substrate and a second separation spacing S2 to the outer surface of the second substrate, so that the laser weld zone is fully enclosed inside the enclosure.
As a material for the first and/or second substrate a variety of materials can be used, e.g., homogeneous glass or monocrystalline silicon, chemically hardened glass, even covered with an optical coating, glass or glasslike material, for example, glass ceramics or crystallines such as crystalline glass. Furthermore, silicone-based substrates can be used, where any of the aforementioned materials can be used in combination with each other.
By means of an example, the laser weld line may be obtained by shooting a short pulsed and focused laser beam (e.g. with repetition rate R) from a laser source into the material with a defined wavelength and energy so that a series of beam spots is placed into the material of the enclosure. The substrates and/or focusing optics are set up such, that the focus of the laser is set farther into the substrate stack than a thickness of that substrate above and next to the intended laser weld line, which is, below the interface. The sample may, during the course of laser irradiation, be translated relatively to the source with a velocity v. The beam spot distance is hence v/R. By placing the beam spots so close together that the resulting melting region at least is in contact with the neighboring melting region, or even overlaps with it, heat accumulation can occur such that a continuous weld line is produced.
In the direction perpendicular to its connecting plane the laser weld line comprises said height HL. The connecting plane is the direction in which the neighboring or consecutive beam spots are set, for example, the contact plane of the inner surfaces of the first and second substrate. Typically, the laser welding is performed from “overhead” perspective, meaning that the substrate stack is positioned, e.g., on a surface, such as a table, and that the laser is shot from above at least through the uppermost substrate layer—or through more than one substrate layers—to the place of the beam focus. The height HL thus is measured in the direction of the laser beam, where the width of the laser weld line is measured perpendicular with respect to the direction of the laser beam.
As introduction of a laser weld line may also introduce stress in certain amounts of material, for example, in the region around the laser weld line, the laser weld zone comprising, for example, a second laser weld line or a laser weld trace may relieve the stress introduced by the first laser weld line. Therefore, the enclosure comprising a laser weld line next to the laser weld zone may comprise an improved mechanical stability.
The invention is described in more detail and in view of preferred embodiments hereinafter. Reference is made to the attached drawings wherein like numerals have been applied to like or similar components.
It is shown in
Next to the laser weld line 6a, two laser weld zones 7a, 7b are provided, which may show an information pattern (see other figures). Advantageously, the information zones 7a, 7b are introduced in the same plane as the laser weld line 6a, introduced to hermetically seal the enclosure 1. A laser weld line may also comprise an information pattern and a laser weld zone may, on the other side, comprise the ability of hermetically sealing an area inside the laser weld zone 7a, 7b.
On the side 12 of the enclosure 1, there is the edge 11 of the glass stack, where a spacing S3 is provided in between the edge 11 of the enclosure 1 and the outermost information zone 7b. In the perspective of
The laser weld line 6a as well as the laser weld zone 7a comprising the first information pattern and the second laser weld zone 7b comprising a second information pattern comprise a first separation spacing S1 to the outer surface 43 of the first substrate 3 and a second separation spacing S2 to the outer surface 41 of the second substrate 4. All laser weld lines 6a and laser weld zones 7a, 7b are therefore fully enclosed inside the enclosure. In particular, the laser weld lines 6a and laser weld zones 7a, 7b do not interfere or reach into the outer surfaces 41, 43 of the substrates 3, 4. At the same time, all provided laser weld lines add in joining the two substrates to each other, so that a total joining force may be the sum of the individual joining or binding force of each individual laser weld line/laser weld zone.
For example, the outer surface 43 or the outer surface 41 may be thinned down, e.g. polished, after introduction of the laser weld zones 7a, 7b, so that the first and/or second separation spacing S1, S2 may be reduced or even vanish. As a result, the laser weld zone 7a, 7b can form part of the outer surface 41 and/or outer surface 43. In other words, the laser weld zone 7a may be exposed to the surrounding to be in contact with the surrounding. However, the information pattern as a homogeneous part of the respective substrate, is not more vulnerable or receptive to damage e.g. introduced by chemicals or any kind of weathering. In contrast, it may form part of a planar and polished outer surface 43 or 41 comprising optical properties which distinguish from the surrounding material—and thus allowing for reading out the information stored in the information pattern—but not comprising a substantially differing material compound or geometrical shape.
A laser weld zone 7a may comprise the feature of hermetically joining the two substrates to each other, so that the additional laser weld line 6a may be omitted. This may depend, for example, on the information pattern to be used in the laser weld zone 7a, 7b, where an information pattern with a continuous laser weld trace can comprise the hermetic sealing function, and a discontinuous laser weld trace with spacings between individual laser dots may not or may also comprise a hermetical sealing function. But the laser weld line 6a may also be part of the laser weld zone 7a and may or may not comprise an information pattern.
Referring to
As depicted in
Referring now to
In
By arranging the information patterns 7a, 7b in two different planes, additional formation of the information may be provided, for example in that viewing of the information patterns from the specific angle may interpose the first information pattern 7a with the second information pattern 7b in such a way that both information patterns together provide a single or combined information structure. Thus, it might be said, that the two information patterns 7a, 7b may complement each other so that they contribute to a single information obtained from a certain readout angle of the enclosure 1.
With respect to
Each laser spot and thus each laser weld line 6a, 6b, 6c, 6d may thus be identifiable, for example by optical means, and an information pattern 7, 7a, 7b may be provided inside the glass by providing a laser weld trace 7a with a characteristic shape or width or intensity and so on in order to encode or store information in the laser trace 7a in the information zone 7. One single laser spot may also be referred to as heating zone 34.
Furthermore, in
Referring to
With respect to
Information to be stored in the information pattern 7a or in the information zone 7 may be related to any retracing ability, for example, during packaging of chips, especially for enclosures used for medical applications. This may comprise the ability to identify the chip, its manufacturer, its date of fabrication and/or if it is from a diced wafer, the wafer type and the localization of the chip on the singulated wafer. But additionally, further information can be stored in the information zone 7, in the case of any readable or accessible data storage inside the enclosure 1, for example, information like access, data, e.g., a password, can be stored in the information zone 7.
In general, the information zone 7 may comprise data such as component data, comprising such as one of wafer information, wherein wafer information may comprise the manufacturer, origin, storage time, price, material, geometry, surface heat, local defects, coatings such as non-organic or organic coatings, date, kind and facility of inspection, possible exposure to x-ray or nuclear radiation and/or particle contamination.
Components' data to be stored in the information zone 7 may also comprise information from the spacer wafer or cavity wafer (which is intermediate layer 4a), such as its manufacturer, source material such as wafer properties, tool and process used for creating the cavities such as sandblasting, laser cutting or etching, and/or glues used in manufacturing the enclosure 1, coatings comprised by the intermediate layer 4a, possible exposure to x-ray or nuclear radiation and particle contamination and the like.
In the case that wafers with Through Glass Vias (TGV) components data to be shown in the information zone 7 may also comprise data on the material of the vias, their geometry, position and also tolerances of a single TGV, its ohmic resistance and so on.
Further information to be provided in the information zone 7 may also comprise data about the enclosed component 5 in the function zone 2 and assembly data. This may include at least one of data related to the component 5 to be enclosed in the enclosure 1 such as manufacturer, ID, possible defects. It may include further one of date, place and operator of placement, used glue or solder or for putting the component 5 into the cavity 2, possible damages, cleanroom data, particle contamination, use of process gas or liquid filling, atmospheric data (pressure, temperature, composition). Another type of component and assembly data could comprise surface quality of to be welded interface 15, 15a.
Furthermore, in the information zone 7, information about bonding and micro welding may be provided such as one of the data, place, machine and operator, operational data of laser, coordinates of welding lines on waferstack, such as X, Y and focal position. The bonding and micro welding data can further comprise temperature of machine, atmosphere, chuck, mechanical holder used, optics used for laser welding, laser beam data, operational data of stage access. The bonding and micro welding data can further comprise position of cavity or of a future chip on the wafer 3, 4 and possible defects. It may even comprise possible postproduction information of wafer such as polishing or a chemical toughening.
Regarding the singulated encapsulation information to be stored in the information zone 7 may comprise one of date, place and operator of singulation, post processing of chips such as polishing and grinding, application of additional coatings and/or polymer enclosures.
The Information to be provided in the information zone 7 may also comprise encapsulation lifetime data such as one of shipment, storage, date of sale, customer and/or sensor lock of device. Of particular interest might be that the information zone 7 comprises a unique identifier and the before-mentioned lifetime data is stored at an external medium, where the data is associated to the unique identifier. Data regarding encapsulation lifetime can also provide one of medical date of insurgent, operation data, checkup data, performance and sensor lock of device. Furthermore, data regarding encapsulation disassembly may be provided in the information zone comprising at least one of the full lifetime data of the product and/or counterfeit identification data.
Turning back to
Referring to
Item B of
Item C of
Item D of
Regarding Item E of
Regarding Item F of
The lines 7a or 7b may be composed by one or several consecutive dots. In line 7a some of the dots may overlap and form short lines, where other dots may not overlap and remain as dots. In line 7b the spacing in between the dots varies and encoding of information can be stored in variation of the dot spacing. Information stored in these dotted lines can be for example binary information (no dot/dot represents 0 or 1) or complex information (line length modulation and so on).
Information in the laser weld zone 7 can therefore also be encoded by varying the velocity v of the inscription laser 50. For example, the movement velocity of a movable table, where the enclosure 1 or the substrate stack 3, 4 is positioned, may be altered during the inscription process in order to vary v.
It is also possible to vary the interspot distance by altering R. In this respect, the repetition rate is typically fixed. But e.g. by using a so-called “pulse picker” and/or by “switching off” a sequence of 1 or more pulses, also R can be altered. The pulse picker can be employed between laser source 50 and focusing optic. It can also be integrated in the laser source 50, e.g. for an ultrashort laser 52 between seed laser and amplifier.
It is also possible that debris from the absorption zone 35 gets transported to the top region of the melt region 36. Such “debris”-spots 39 would also carry the longitudinal information induced by the spot-to-spot distance. So in other words, in the absorption zone 35 the optical properties of the material may be amended such, that this material may be optically detectable and part of this material may be transported through the melting region 36 to its top, where it rests during solidifying of the melting zone. With respect to
Referring to
In Step B as shown in
For example, a Bond Quality Index Q1 is obtained when Q1=1−(A−G)/A. Herein, A corresponds to the contact area 15, 15a between each two substrates or wafers 3, 4, 4a. G corresponds to the area, wherein the a possibly remaining separation or spacing (e.g. due to remaining particles or unevenness of the substrates) in between the two substrates 3, 4, 4a, and in the contact area 15, 15a is smaller than a predefined value P. This value P corresponds to, e.g., a separation in between the two substrates 3, 4, 4a of 5 μm or less, preferably 2 μm or less, further preferably 1 μm or less. In other words, the Bond Quality Index Q1 describes the percentage of the contact area 15, 15a where separation between the two neighboring substrates 3, 4, 4a is less than P. It is further preferred to establish a first Bond Quality Index Q1 before laser welding the wafer stack and a second Bond Quality Index Q2 after laser welding the wafer stack. Although it is possible to bridge possible gaps (separation) between two neighboring substrates 3, 4, 4a with the laser weld line and nevertheless obtain a solid and resilient connection between the welded substrates 3, 4, 4a, it has been found out that residual strain may result in one or both substrates 3, 4, 4a after welding, if such a separation was bridged by the laser weld line. These residual strain in the substrate may even show a characteristic in that it is not measurable in the later product, or may only be measured with a high effort. This may result in premature wear or failure. By means of comparing Q1 with Q2 it is possible to estimate residual tension and/or possible shortage on lifetime of the enclosure 1.
Step C of the method shown in
Step D as shown in
Step E as shown in
All dimension data mentioned hereinabove in the specification may be read out, for example, by optical means or by a handheld device and be stored in the database 62 shown in
It will be appreciated that the features defined herein in accordance with any aspect of the present invention or in relation to any specific embodiment of the invention may be utilized, either alone or in combination with any other feature or aspect of the invention or embodiment. In particular, the present invention is intended to cover an enclosure 1 and/or a method of manufacturing an enclosure 1 configured to include any feature described herein. It will be generally appreciated that any feature disclosed herein may be an essential feature of the invention alone, even if disclosed in combination with other features, irrespective of whether disclosed in the description, the claims and/or the drawings.
It will be further appreciated that the above-described embodiments of the invention have been set forth solely by way of example and illustration of the principles thereof and that further modifications and alterations may be made therein without thereby departing from the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21202796.5 | Oct 2021 | EP | regional |
| PCTEP2022076057 | Sep 2022 | WO | international |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/076057 | 9/20/2022 | WO |
