Techniques for alignment of at least two elements by magnetic mating

Abstract

The disclosure relates to an apparatus (130) for alignment of at least two elements (110, 120), the apparatus (130) comprising: a first magnet pattern (132) configured to attract a first magnet pattern (112) of a first element (110) of the at least two elements (110, 120), which is aligned with a reference feature (111) of the first element (110), by magnetic force (134) such that both magnet patterns (112, 132) are aligned with respect to each other; and a second magnet pattern (133) configured to attract a first magnet pattern (122) of a second element (120) of the at least two elements (110, 120), which is aligned with a reference feature (121) of the second element (120), by magnetic force (135) such that both magnet patterns (122, 132) are aligned with respect to each other and thus the reference feature (111) of the first element (110) is aligned to the reference feature (121) of the second element (120). The disclosure further relates to a corresponding element, corresponding methods and further to a multiple element arrangement (400b, 400c) where a second element (120) is attached to a first element (110) by magnetic force between two magnet patterns (112, 123).

Description

[0001] Techniques for alignment of at least two elements by magnetic mating

[0002] TECHNICAL FIELD

[0003] The disclosure relates to the field of die-bonding, particularly in optics and photonics packaging. In particular, the disclosure relates to techniques for alignment of at least two elements such as semiconductor chips, dies or other elements, by magnetic mating. Specifically, one method and one apparatus for passive alignment are disclosed.

[0004] BACKGROUND

[0005] For chip-packaging in photonics and optics, one key task is to align two optical / photonic components on a chiplet level to optimize the system performance, e.g. to couple an active component (a laser or an emitting source... ) to a passive element (waveguide, fiber... ) or couple light between two passive elements. Two die-bonding technologies, namely passive alignment, which is fast but has limited accuracy, and active alignment, which is more accurate but slow, are used to achieve photonic / optical alignment in industry applications. For industrial applications, e.g. integration optics, die-bonding technologies for photonic / optical alignment are required that are simultaneously fast and accurate.

[0006] SUMMARY

[0007] This disclosure provides a solution for overcoming the above-described problems of die-bonding. In particular, a solution is presented for providing die-bonding simultaneously with high speed and high accuracy, particularly it can provide optical / pho tonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0008] Embodiments presented in this disclosure can provide alignment with a positioning precision of less than 100 nanometers or so.

[0009] The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

[0010] According to a first aspect, the disclosure relates to an apparatus for alignment of at least two elements, the apparatus comprising: a first magnet pattern configured to attract a first magnet pattern of a first element of the at least two elements, which is aligned with a reference feature of the first element, by magnetic force such that both magnet patterns are aligned with respect to each other; and a second magnet pattern configured to attract a first magnet pattern of a second element of the at least two elements, which is aligned with a reference feature of the second element, by magnetic force such that both magnet patterns are aligned with respect to each other and thus the reference feature of the first element is aligned to the reference feature of the second element.

[0011] Such an apparatus provides a tool for die-bonding simultaneously with high speed and high accuracy for the in-plane alignment scenario. This apparatus can provide optical / pho tonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0012] The above elements that are aligned by the apparatus can be semiconductor chips, for example, or other elements like PCBs, photodiodes, coils, vapor cells, optical waveguides, etc. or any combination of such elements. They can be active elements and / or passive elements.

[0013] Although in the above apparatus just two elements are defined, it is understood that the scope is not limited to just two elements.

[0014] There can exist 3, 4, 5 and more elements that are aligned by the apparatus as the wording “at least two elements” indicates. The reference features as defined in this disclosure are not just physical ports or shapes, but more they are solid structures through the whole element. One reference feature can have two interface ports (e.g. input and output), for example which do not have to be arranged along one axis, e.g. an optical path from the first interface to the second interface, this optical path can rather be an arbitrary curve.

[0015] In an exemplary implementation of the apparatus, the first magnet pattern of the apparatus is configured to attract the first magnet pattern of the first element by a magnetic force that is strong enough to overcome a weight of the first element; and the second magnet pattern of the apparatus is configured to attract the first magnet pattern of the second element by a magnetic force that is strong enough to overcome a weight of the second element.

[0016] By overcoming the weight of the first and second element, the apparatus can be applied for aligning the first element with the second element in each space position, independently of a gravity vector.

[0017] In an exemplary implementation of the apparatus, the reference feature of the first element comprises a critical area and the reference feature of the second element comprises a critical area; and the apparatus is configured to align the critical area of the first element to the critical area of the second element.

[0018] This allows to couple the critical areas of two elements with respect to each other even for different outlines of the two elements. For example, two elements can be coupled with respect to each other by their critical areas even when the two elements have a different size or shape.

[0019] A critical area according to this disclosure is an area of the element where a coupling with another element takes place, for example an optical waveguide section where light is passed from a first optical waveguide to a second optical waveguide or, for example, an active area of a first element where light is produced for transmission to a second element.

[0020] In an exemplary implementation of the apparatus, the critical area of the first element comprises a first optical or photonic component and the critical area of the second element comprises a second optical or photonic component; and the apparatus is configured to align the optical or photonic component of the first element to the optical or photonic component of the second element.

[0021] This allows easy optical or photonic coupling of two elements such as chips, etc.

[0022] In an exemplary implementation of the apparatus, each of the two elements comprises a first main surface, a second main surface opposite to the first main surface and one or more side surfaces between the first main surface and the second main surface; and the apparatus comprises a first main surface, a second main surface opposite to the first main surface and one or more side surfaces between the first main surface and the second main surface; wherein the first main surfaces of the two elements are facing the second main surface of the apparatus when the two elements are attracted to the apparatus.

[0023] This allows to couple physical elements of specific geometries which are defined by their surfaces, with each other.

[0024] In an exemplary implementation of the apparatus, the reference feature of the first element is arranged at a first surface of the first element; wherein the reference feature of the second element is arranged at a second surface of the second element; and wherein the first and second magnet patterns of the apparatus are configured to attract the first magnet patterns of the elements such that the first surface of the first element faces the second surface of the second element. This allows to couple the two elements by their surfaces, on which the magnet patters are mirrored.

[0025] In an exemplary implementation of the apparatus, the reference feature of the first element is aligned to the first main surface of the first element; wherein the reference feature of the second element is aligned to the first main surface of the second element; such that the reference feature of the first element is aligned to the reference feature of the second element independently of a thickness difference between the first element and the second element.

[0026] This allows to couple two elements of different thickness (or size).

[0027] In an exemplary implementation of the apparatus, the magnet patterns of the apparatus are arranged along the second main surface of the apparatus.

[0028] This allows an easy fabrication of the magnet patterns of the apparatus since they can be disposed along the second main surface.

[0029] In an exemplary implementation of the apparatus, the magnet patterns of the apparatus are facing the magnet patterns of the first and second elements in order to initiate the magnetic forces attracting the first and second elements to the apparatus; and wherein a geometric shape of the magnet patterns of the apparatus corresponds to a geometric shape of the magnet patterns of the first and second elements.

[0030] Such a shape allows an optimal magnetic mating and produces a strong magnetic force for attracting the elements towards the apparatus.

[0031] In an exemplary implementation of the apparatus, the geometric shape of the magnet patterns of the apparatus forms two or more parallel stripes or any other geometrical figure.

[0032] Such stripes can be easily produced. However, any other geometrical shape can be applied as well.

[0033] In an exemplary implementation of the apparatus, the apparatus comprises: a switch configured to control a magnetization of the first and second magnet patterns of the apparatus for an attraction, a repulsion or a negligible interaction of the magnet patterns of the first and second elements.

[0034] By such a switch, the elements which are aligned with respect to each other can be easily released from the apparatus.

[0035] In an exemplary implementation of the apparatus, the switch comprises an electro-magnet configured to increase or decrease the magnetic forces of the magnet patterns of the apparatus; and / or the switch comprises a heating source configured to heat the magnet patterns of the apparatus above their Curie temperatures in order to mitigate the magnetic forces of the magnet patterns of the apparatus.

[0036] An electro-magnet can be easily implemented for providing an on- and off- switching of the magnetic force. A heating source can be efficiently applied for mitigating the magnetic forces.

[0037] According to a second aspect, the disclosure relates to an element, comprising: a reference feature; and a first magnet pattern which is aligned with the reference feature; wherein the first magnet pattern is configured to be attracted by a first magnet pattern of an apparatus according to any of the preceding claims such that the first magnet pattern of the element is aligned with the first magnet pattern of the apparatus and the reference feature of the element is aligned with a reference feature of a second element which first magnet pattern is aligned with the reference feature of the second element and attracted by a second magnet pattern of the apparatus.

[0038] Such an element can be used for die-bonding simultaneously with high speed and high accuracy for the in-plane alignment scenario. The element allows optical / photonic coupling with other elements of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0039] In an exemplary implementation of the element, a geometric shape of the first magnet pattern of the element spatially mirrors with a geometric shape of the first magnet pattern of the apparatus.

[0040] Such a geometric shape allows an optimal magnetic mating and produces a strong magnetic force for attracting the elements towards the apparatus.

[0041] In an exemplary implementation of the element, the element comprises a first main surface, a second main surface opposite to the first main surface and one or more side surfaces between the first main surface and the second main surface; and the apparatus comprises a first main surface, a second main surface opposite to the first main surface and one or more side surfaces between the first main surface and the second main surface; wherein the first main surface of the element is facing the second main surface of the apparatus when the element is attracted by the apparatus.

[0042] This allows to couple physical elements of specific geometries which are defined by their surfaces, with each other.

[0043] In an exemplary implementation of the element, the reference feature of the element is arranged at a first surface of the element; and the first magnet pattern of the apparatus is configured to attract the first magnet pattern of the element such that the first surface of the element faces a second surface of the second element at which the reference feature of the second element is arranged.

[0044] This allows to couple the two elements by their surfaces, on which the magnet patterns are mirrored.

[0045] In an exemplary implementation of the element, the reference feature of the element is aligned to the first main surface of the element; such that the reference feature of the element is aligned to the reference feature of the second element independently of a thickness difference between the element and the second element.

[0046] This allows to couple two elements of different thickness (or size).

[0047] In an exemplary implementation of the element, the first magnet pattern of the element is arranged along the first main surface of the element.

[0048] This allows an easy fabrication of the first magnet pattern of the element since it can be disposed along the first main surface of the element.

[0049] In an exemplary implementation of the element, the first magnet pattern of the element is arranged to spatially mirror with the first magnet pattern of the apparatus.

[0050] Such a geometric arrangement produces a strong magnetic force for attracting the element to the apparatus. According to a third aspect, the disclosure relates to a system comprising the apparatus according to the first aspect and two or more elements according to the second aspect; wherein the first magnet pattern of the apparatus is configured to attract the first magnet pattern of a first element of the at least two elements by magnetic force such that both magnet patterns are aligned with respect to each other; and the second magnet pattern of the apparatus is configured to attract the first magnet pattern of a second element of the at least two elements by magnetic force such that both magnet patterns are aligned with respect to each other and thus the reference feature of the first element is aligned to the reference feature of the second element.

[0051] Such a system provides the same benefits as the apparatus and the elements described above, i.e., allowing die-bonding simultaneously with high speed and high accuracy for the in-plane alignment scenario. The system can provide optical / pho tonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0052] According to a fourth aspect, the disclosure relates to a method for aligning a first element with a second element, the method comprising: attracting a first magnet pattern of a first element, which is aligned with a reference feature of the first element, by magnetic force with a first magnet pattern of an apparatus according to the first aspect described above such that both magnet patterns are aligned with respect to each other; and attracting a first magnet pattern of a second element, which is aligned with a reference feature of the second element, by magnetic force with a second magnet pattern of the apparatus such that both magnet patterns are aligned with respect to each other and thus the reference feature of the first element is aligned to the reference feature of the second element.

[0053] Such a method provides the same benefits as the apparatus and the elements described above, i.e., allowing die-bonding simultaneously with high speed and high accuracy for the in-plane alignment scenario. The method can provide optical / photonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0054] In an exemplary implementation of the method, the first magnet pattern of the first element and the first magnet pattern of the second element are simultaneously or nearly simultaneously attracted by the apparatus.

[0055] This allows to improve the speed for aligning the first element with the second element.

[0056] In an exemplary implementation of the method, the method comprises: attaching the first element, attracted to the first magnet pattern of the apparatus, and the second element, attracted to the second magnet pattern of the apparatus, onto a base element by using a bonding layer.

[0057] By attaching the two elements onto a base element, the whole stack of elements can be easily produced and carried by the base element.

[0058] The base element can be a substrate, for example, or a carrier or a base plate, for example.

[0059] In an exemplary implementation of the method, the method comprises: mitigating or reversing the magnetic forces of the first and second magnet patterns of the apparatus to remove the first and second elements, which are attached to the base element, from the apparatus.

[0060] This allows to easily resolve the elements aligned with respect to each other from the apparatus. According to a fifth aspect, the disclosure relates to a multiple element arrangement, comprising: a base element; a first element of a plurality of elements attached to the base element, the first element comprising a reference feature and a first magnet pattern which is aligned with the reference feature of the first element; and a second element of the plurality of elements attached to the first element, the second element comprising a reference feature and a second magnet pattern which is aligned with the reference feature of the second element; wherein the second element is attached to the first element by magnetic force between the first magnet pattern of the first element and the second magnet pattern of the second element such that both magnet patterns are aligned with respect to each other and thus the reference feature of the first element is aligned to the reference feature of the second element.

[0061] Such a multiple element arrangement allows die-bonding simultaneously with high speed and high accuracy for the vertical alignment scenario. The multiple element arrangement can provide optical / photonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0062] The above elements that are aligned with respect to each other can be semiconductor chips, for example, or other elements like PCBs, photodiodes, coils, vapor cells, optical waveguides, etc. or any combination of such elements. They can be active elements and / or passive elements.

[0063] Although just two elements are defined for the above multiple element arrangement, it is understood that the scope is not limited to just two elements. There can exist 3, 4, 5 and more elements that are aligned with respect to each other by magnetic force of their magnet patterns as the wording “of a plurality of elements” indicates.

[0064] In an exemplary implementation of the multiple element arrangement, the multiple element arrangement comprises: a third element of the plurality of elements attached to the second element, the third element comprising a reference feature and a second magnet pattern which is aligned with the reference feature of the third element; wherein the second element comprises a first magnet pattern which is aligned with the reference feature of the second element; wherein the third element is attached to the second element by magnetic force between the first magnet pattern of the second element and the second magnet pattern of the third element such that both magnet patterns are aligned with respect to each other and thus the reference feature of the third element is aligned to the reference features of the first and second elements.

[0065] The multiple element arrangement thus can form a stack of elements which are stacked above each other such that their reference features are aligned with respect to each other.

[0066] In an exemplary implementation of the multiple element arrangement, the first element is attached to the base element by a bonding layer.

[0067] This results in a stable and robust connection of the elements which are aligned with each other with the base element.

[0068] In an exemplary implementation of the multiple element arrangement, the second element is attached to the first element additionally to the magnetic force by a second bonding layer.

[0069] By using such second bonding layer, the connection of the elements can be improved with respect to stability and durability.

[0070] In one exemplary implementation, the multiple element arrangement can be produced by the following steps:

[0071] 1. die-bonding chip 1 on the substrate;

[0072] 2. stack chip 2 on chip 1 by magnetic mating and die-bonding them; 3. stack chip 3 on chip 2 by magnetic mating and die-bonding them;

[0073] N. stack chip N on chip (N-l) and die-bonding them.

[0074] This allows to produce a multiple element arrangement with a large number of elements aligned with respect to each other.

[0075] According to a sixth aspect, the disclosure relates to a method for producing a multiple element arrangement comprising a base element and a plurality of elements, the method comprising: attaching a first element of the plurality of elements to the base element, the first element comprising a reference feature and a first magnet pattern which is aligned with the reference feature of the first element; and attaching a second element of the plurality of elements to the first element, the second element comprising a reference feature and a second magnet pattern which is aligned with the reference feature of the second element; wherein the second element is attached to the first element by magnetic force between the first magnet pattern of the first element and the second magnet pattern of the second element such that both magnet patterns are aligned with respect to each other and thus the reference feature of the first element is aligned to the reference feature of the second element.

[0076] Such a method provides the same benefits as the multiple element arrangement as described above, i.e., allowing die-bonding simultaneously with high speed and high accuracy for the vertical alignment scenario. The method can provide optical / pho tonic coupling of low-coupling loss for massive production with low time cost and high coupling accuracy.

[0077] In an exemplary implementation of the method, the method comprises: attaching a third element of the plurality of elements to the second element, the third element comprising a reference feature and a second magnet pattern which is aligned with the reference feature of the third element; wherein the second element comprises a first magnet pattern which is aligned with the reference feature of the second element; wherein the third element is attached to the second element by magnetic force between the first magnet pattern of the second element and the second magnet pattern of the third element such that both magnet patterns are aligned with respect to each other and thus the reference feature of the third element is aligned to the reference features of the first and second elements.

[0078] This allows to produce a multiple element arrangement with three and more elements which are aligned with respect to each other.

[0079] BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Further embodiments of the disclosure will be described with respect to the following figures, in which:

[0081] Figure 1 shows a passive alignment system 100 for in-plane alignment of at least two elements 110, 120 by using an apparatus 130 according to an embodiment;

[0082] Figures 2a, 2b and 2c show a method for in-plane alignment of at least two elements 110, 120 with magnetic mating 200a (Figure 2a), bonding 200b (Figure 2b) and switch-off / reverse electro-magnet 200c (Figure 2c) according to an embodiment;

[0083] Figure 3 shows a passive alignment system 300 for vertical alignment of at least two elements 110, 120 according to an embodiment; and

[0084] Figures 4a, 4b and 4c show a method for vertical alignment of at least two elements 110, 120 with die bonding first element 110 on substrate 400a (Figure 4a), die bonding 400b second element 120 on first element 110 (Figure 4b) and die bonding N- 1thelement on N111element 400c (Figure 4c) according to an embodiment.

[0085] DETAILED DESCRIPTION OF EMBODIMENTS

[0086] In the following detailed description, reference is made to the accompanying drawings, which form a part thereof, and in which is shown by way of illustration specific aspects in which the disclosure may be practiced. It is understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the disclosure is defined by the appended claims.

[0087] It is understood that comments made in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.

[0088] In this disclosure alignment techniques for die-bonding are described, in particular passive alignment and active alignment.

[0089] Passive alignment is mostly dedicated to fast chip-packaging, in which fiducials are in advance produced on chips. By using inspection tools of the die-bonding machines, chips can be aligned from fiducials, not only for a chip-to-chip coupling, but also on a wafer-to-wafer level. The highest accuracy is approximately 200 nm on the market, and the alignment time is on the order of seconds or even shorter. Most machines on the market have alignment accuracy on the order of micrometers. Embodiments described in this disclosure present passive alignment techniques which alignment accuracy can be significantly below 200 nm.

[0090] Active alignment is in comparison slower, as the alignment is performed by referring to the optical detection signal. The alignment is done if the maximum signal is achieved. The accuracy can be as good as less than 50 nm, and the alignment time is on the order of 10 seconds. Active alignment aims light coupling between two single optical interfaces, and it is not designed for light coupling on a wafer-to-wafer level. The alignment time of active alignment is typically long, on the order of a few seconds or up to 10 seconds. Embodiments described in this disclosure present alignment techniques which alignment time is in the order of fractions of a second down to the order of milliseconds.

[0091] The present disclosure makes use of large anisotropy of magnetic interactions between two microscale magnets to achieve alignment of two elements. In the description, alignment of two or more elements, in particular semiconductor chips is presented to achieve photonic / optical coupling of high efficiency in a passive way.

[0092] The disclosure presents solutions for two different techniques for passive alignment: In-plane alignment and vertical alignment for optical / pho tonic coupling. In-plane alignment for optical / photonic coupling is described below with respect to Figures 1 and 2a / b / c. Vertical alignment for optical / photonic coupling is described below with respect to Figures 3 and 4a / b / c.

[0093] In this disclosure, reference features are described. A reference feature is arranged at a certain location of the element and can be aligned with another reference feature of another element in order to couple both elements with respect to each other. Reference features may comprise a critical area or an active area of a chip, i.e., an area of the element where a coupling with another element takes place, for example an optical waveguide section where light is passed from a first optical waveguide to a second optical waveguide or, for example, an active area of a first element where light is produced for transmission to a second element, etc.

[0094] Before describing in-plane alignment and vertical alignment in detail with respect to Figures 1 to 4c, in the following a short description of both techniques is presented for gaining a better understanding. In-plane alignment

[0095] To align the critical area (see reference signs 111, 121 indicating the rectangle on the side in Figure 1) from Chip 1 to the critical area of another Chip 2, the strong magnetic force from the magnet stray field can be used. Magnet pattern A and B are defined on the top surface of Chip 1 and Chip 2, respectively; The magnet can be a hard magnet material which has a high coercive field and a high Tc. [To note, magnet pattern A - A ’ and B-B ’ are not necessarily stripes. The stripe structure is only an example for an easy understanding of the explanation of this magnet-mating principle.] As the key part, a master sample needs to be carefully produced. On the bottom side of the master sample, pattern A’ is defined in a mirrored way to perfectly match pattern A of Chip 1 and pattern B’ is defined in a mirrored way to perfectly match pattern B of Chip 2. In addition, the distance between A’ and B’ is designed to determine the gap distance between Chip 1 and Chip 2 after the alignment process. The magnetic material on the master sample can be a material with high magnetic permeability, e.g. high-mu material, and the magnetization can be switched by another electromagnet atop. Therefore, the master sample can be regarded in general as an electro-magnet, for which the magnetic pattern is by purpose designed to mate Chip 1 and Chip 2.

[0096] These patterns above are expected to have a length of a few 100 |im, a width of a few |im and a thickness of a few 100 nm to a few |im. The strength of the magnetic field is expected to be larger than several 100 mT at a height of 1 |im above the surface. When A and B are approaching A’ and B’ on the master sample, the strong magnetic force on the order of 0.1 mN can quickly mate A with A’ and B with B’, to achieve the self-mating process. This force is strong enough to overcome the weight of Chip 1 and Chip 2. Such a magnetic mating process “automatically” finishes the alignment process of Chip 1 and Chip 2 with an accuracy which is determined by the fabrication accuracy of all patterns. As the patterns can very precisely be defined by lithography technique, film deposition and etching process, and thus the accuracy can be on the order of 100 nm or even less.

[0097] To note, all values related to structure size, magnetic strength can be varied to meet the applications, depending on specific designs of chips or chiplets.

[0098] Vertical alignment

[0099] There can be applications to align elements along the vertical direction, e.g. the optical center of each element is dedicated to be aligned. Figure 3 schematically describes the main steps to perform magnetic mating along the vertical direction. Similar to the in-plane alignment, magnetic patterns are defined to magnetically mate two elements. Here the interaction happens straightforwardly between two elements that are to be aligned, no “master sample” is needed.

[0100] Firstly element 1 is die-bonded on the substrate. To make magnetic mating for element 2 above element 1, a magnetic pattern is defined on the top surface of element 1 and its mirrored magnetic pattern is defined on the bottom surface of element 2. In this way, if element 2 is moved by a tool, e.g. one gripper, slightly above and close to element 1, the magnetic mating can happen automatically. Then the die-bonding process, e.g. epoxy or eutectic bonding, is done on around the interface between element 1 and element 2. To note, the pattern is defined so that the optical axis or the optical center (reference signs 111, 121, 151 indicating small circles) of two elements are aligned.

[0101] Secondly element 3 is magnetically mated to element 2 in a same way, and thus die-bonded.

[0102] Similar steps can be repeated until element (N- 1 ) is die-bonded on element N.

[0103] As a consequence, all N elements are optically aligned along the vertical direction.

[0104] Figure 1 shows a passive alignment system 100 for in-plane alignment of at least two elements 110, 120 by using an apparatus 130 according to an embodiment. The apparatus 130 can be used for alignment of at least two elements 110, 120. The apparatus 130 comprises a first magnet pattern 132 configured to attract a first magnet pattern 112 of a first element 110 of the at least two elements 110, 120) which is aligned with a reference feature 111 of the first element 110, by magnetic force 134 such that both magnet patterns 112, 132 are aligned with respect to each other. The apparatus 130 comprises a second magnet pattern 133 configured to attract a first magnet pattern 122 of a second element 120 of the at least two elements 110, 120, which is aligned with a reference feature 121 of the second element 120, by magnetic force 135 such that both magnet patterns 122, 132 are aligned with respect to each other and thus the reference feature 111 of the first element 110 is aligned to the reference feature 121 of the second element 120.

[0105] The above elements that are aligned by the apparatus can be semiconductor chips, for example, or other elements like PCBs, photodiodes, coils, vapor cells, optical waveguides, etc. or any combination of such elements. They can be active elements and / or passive elements.

[0106] Although just two elements are shown in Figure 1 for the apparatus 130, it is understood that the scope is not limited to just two elements. There can exist 3, 4, 5 and more elements that are aligned by the apparatus as the wording “at least two elements” indicates.

[0107] The first magnet pattern 132 of the apparatus 130 may be configured to attract the first magnet pattern 112 of the first element 110 by a magnetic force 134 that is strong enough to overcome a weight of the first element 110. The second magnet pattern 133 of the apparatus 130 may be configured to attract the first magnet pattern 122 of the second element 120 by a magnetic force 135 that is strong enough to overcome a weight of the second element 120.

[0108] The reference feature 111 of the first element 110 may comprise a critical area and the reference feature 121 of the second element 120 may comprise a critical area. The apparatus 130 may be configured to align the critical area of the first element 110 to the critical area of the second element 120.

[0109] A critical area according to this disclosure is an area of the element where a coupling with another element takes place, for example an optical waveguide section where light is passed from a first optical waveguide to a second optical waveguide or, for example, an active area of a first element where light is produced for transmission to a second element.

[0110] The critical area of the first element 110 may comprise a first optical or photonic component. The critical area of the second element 120 may comprise a second optical or photonic component. The apparatus 130 may be configured to align the optical or photonic component of the first element 110 to the optical or photonic component of the second element 120.

[0111] Each of the two elements 110, 120 may comprise a first main surface 110a, 120a, a second main surface 110b, 120b opposite to the first main surface 110a, 120a and one or more side surfaces 110c, 1 lOd, 120c, 120d between the first main surface 110a, 120a and the second main surface 110b, 120b as shown in Figure 1.

[0112] The apparatus 130 may comprise a first main surface 130a, a second main surface 130b opposite to the first main surface 130a and one or more side surfaces 130c, 130d between the first main surface 130a and the second main surface 130b as shown in Figure 1.

[0113] The first main surfaces 110a, 120a of the two elements 110, 120 may be facing the second main surface 130b of the apparatus 130 when the two elements 110, 120 are attracted to the apparatus 130 as shown in F igure 1. The reference feature 111 of the first element 110 may for example be arranged at a first surface 1 lOd of the first element 110 as shown in Figure 1. The reference feature 121 of the second element 120 may for example arranged at a second surface 120e of the second element 120 as shown in Figure 1. The first and second magnet patterns 132, 133 of the apparatus 130 may be configured to attract the first magnet patterns 112, 122 of the elements 110, 120 such that the first surface 1 lOd of the first element 110 faces the second surface 120e of the second element 120 as shown in Figure 1.

[0114] The reference feature 111 of the first element 110 may be aligned to the first main surface 110a of the first element 110 and the reference feature 121 of the second element 120 may be aligned to the first main surface 120a of the second element (120); such that the reference feature 111 of the first element 110 is aligned to the reference feature 121 of the second element 120 independently of a thickness difference between the first element 110 and the second element 120 as can be seen from Figure 1.

[0115] The magnet patterns 132, 133 of the apparatus 130 may be arranged along the second main surface 130b of the apparatus 130 as shown in Figure 1.

[0116] The magnet patterns 132, 133 of the apparatus 130 can be arranged in such a way that, they are by the middle plane of either 132 and 112 or 133 and 122 mirrored with magnet patterns 112, 122 of the first and second elements 110, 120, i.e. 132 mirrored with 112 and 133 mirrored with 122.

[0117] The magnet patterns 132, 133 of the apparatus 130 may be facing the magnet patterns 112, 122 of the first and second elements 110, 120 as shown in Figure 1 in order to initiate the magnetic forces 134, 135 attracting the first and second elements 110, 120 to the apparatus (130).

[0118] A geometric shape of the magnet patterns 132, 133 of the apparatus 130 may correspond to a geometric shape of the magnet patterns 112, 122 of the first and / or second elements 110, 120.

[0119] The geometric shape of the magnet patterns 132, 133 of the apparatus 130 may form two or more parallel stripes as exemplarily shown in Figure 1 or any other geometrical figure. The stripes shown in Figure 1 are just an example. For example, any regular or irregular shape may be used. This geometrical figure may be continuous or interrupted, e.g., comprising of multiple sections which can have the same or different shapes.

[0120] The apparatus 130 may comprise a switch 131 configured to control a magnetization of the first and second magnet patterns 132, 133 of the apparatus 130 for an attraction, a repulsion or a negligible interaction of the magnet patterns 112, 122 of the first and second elements 110, 120.

[0121] The switch 131 may comprise an electro-magnet configured to increase or decrease the magnetic forces 134, 135 of the magnet patterns 132, 133 of the apparatus 130. In Figure 1, an exemplary number of three coils is shown which is only for illustration of the electro-magnet. This electro-magnet may have any other shape, for example comprising a single coil or any other number of coils.

[0122] The switch 131 may comprise a heating source configured to heat the magnet patterns 132, 133 of the apparatus 130 above their Curie temperatures in order to mitigate the magnetic forces 134, 135 of the magnet patterns 132, 133 of the apparatus 130.

[0123] Figure 1 also shows an exemplary number of two elements 110, 120 according to the disclosure. Such an element (e.g. element 110 on the left-hand side of the picture) comprises: a reference feature 111; and a first magnet pattern 112 which is aligned with the reference feature 111. The first magnet pattern 112 of the element 110 is configured to be attracted by the first magnet pattern 132 of the apparatus 130 as shown in Figure 1 and described above such that the first magnet pattern 112 of the element 110 is aligned with the first magnet pattern 132 of the apparatus 130. Then the reference feature 111 of the element 110 is aligned with the reference feature 121 of a second element 120 which first magnet pattern 122 (of the second element 120) is aligned with the reference feature 121 of the second element 120 and attracted by a second magnet pattern 133 of the apparatus 130.

[0124] The same properties as described for the (first) element 110 also apply for the second element 120 shown in Figure 1.

[0125] A geometric shape of the first magnet pattern 112 of the element 110 may spatially mirror with a geometric shape of the first magnet pattern 132 of the apparatus 130 as shown in Figure 1.

[0126] As already mentioned above but here in the context of the element 110, the element 110 may comprise a first main surface 110a, a second main surface 110b opposite to the first main surface 110a and one or more side surfaces 110c, 1 lOd between the first main surface 110a and the second main surface 110b as shown in Figure 1.

[0127] As already mentioned above but here in the context of the element 110, the apparatus 130 may comprise a first main surface 130a, a second main surface 130b opposite to the first main surface 130a and one or more side surfaces 130c, 130d between the first main surface 130a and the second main surface 130b as shown in Figure 1.

[0128] The first main surface 110a of the element 110 may be facing the second main surface 130b of the apparatus 130 when the element 110 is attracted by the apparatus 130.

[0129] The reference feature 111 of the element 110 may be arranged at a first surface 1 lOd of the element 110 as shown in Figure 1 as one example. The first magnet pattern 132 of the apparatus 130 may be configured to attract the first magnet pattern 112 of the element 110 such that the first surface 1 lOd of the element 110 faces a second surface 120e of the second element 120 at which the reference feature 111 of the second element 120 is arranged as shown in Figure 1.

[0130] The reference feature 111 of the element 110 may be aligned to the first main surface 110a of the element 110; such that the reference feature 111 of the element 110 is aligned to the reference feature 121 of the second element 120 independently of a thickness difference between the element 110 and the second element 120.

[0131] The first magnet pattern 112 of the element 110 may be arranged along the first main surface 110a of the element 110 as shown in Figure 1.

[0132] The first magnet pattern 112 of the element 110 may be arranged to spatially mirror with the first magnet pattern 132 of the apparatus 130 as shown in Figure 1, for example.

[0133] Figure 1 also shows a system 100 comprising the apparatus 130 and two or more elements 110, 120 as described above.

[0134] Figures 2a, 2b and 2c show a method for in-plane alignment of at least two elements 110, 120 with magnetic mating 200a (Figure 2a), bonding 200b (Figure 2b) and switch-off / reverse electro-magnet 200c (Figure 2c) according to an embodiment. As an example, Figures 2a / b / c schematically describe the main steps to finish photonic alignment with a die-bonding process along the in-plane direction. In particular, the main steps to perform magnetic mating of two photonic chips 110, 120 along the in-plane direction with a die-bonding process on a substrate 140 are shown.

[0135] Such a method for aligning a first element 110 with a second element 120 comprises (see Figure 2a):

[0136] Attracting 200a a first magnet pattern 112 of a first element 110, which is aligned with a reference feature 111 of the first element 110, by magnetic force 134 with a first magnet pattern 132 of an apparatus 130 as described above with respect to Figure 1 such that both magnet patterns 112, 132 are aligned with respect to each other; and

[0137] Attracting 200a a first magnet pattern 122 of a second element 120, which is aligned with a reference feature 121 of the second element 120, by magnetic force 135 with a second magnet pattern 133 of the apparatus 130 such that both magnet patterns 122, 132 are aligned with respect to each other and thus the reference feature 111 of the first element 110 is aligned to the reference feature 121 of the second element 120.

[0138] The first magnet pattern 112 of the first element 110 and the first magnet pattern 122 of the second element 120 may be simultaneously or nearly simultaneously attracted by the apparatus 130.

[0139] The method may further comprise (see Figure 2b): Attaching 200b the first element 110, attracted to the first magnet pattern 132 of the apparatus 130, and the second element 120, attracted to the second magnet pattern 133 of the apparatus 130, onto a base element 140 (e.g., a substrate) by using a bonding layer 141 as shown in Figure 2b.

[0140] The base element 140 can be a substrate, for example, or a carrier or a base plate, for example.

[0141] The method may further comprise (see Figure 2c): Mitigating or reversing 200c the magnetic forces 134, 135 of the first and second magnet patterns 132, 133 of the apparatus 130 to remove the first and second elements 110, 120, which are attached to the base element 140, from the apparatus 130. Such mitigating or reversing 200c may be performed by a switch 131 as shown in Figure 2c and described above with respect to Figure 1.

[0142] In the following, further embodiments are described.

[0143] In a first embodiment, the passive alignment can be automatically performed by magnetic mating, which is achieved by magnetic force between the two samples to be aligned and the so-called master sample (here the apparatus 130). Neither the magnetic materials nor the design of the magnetic-mating concept is necessarily fixed to one solution or a few. For instance, the magnetic materials can be magnetic materials with an easy axis either along the out-of-plane direction or along the in-plane direction.

[0144] In a second embodiment, the magnetic mating can be performed at top surfaces of two chips or two wafers. In this second embodiment, the magnetic force can be sufficient to guarantee the alignment accuracy. In addition, this can also overcome the fact that, the thickness difference of two substrates is not needed to be compensated.

[0145] In a third embodiment, the magnetization of the master sample (here the apparatus 130) can be electrically switchable and controllable. This electro-magnet can be used to separate the master sample 130 from the two samples 110, 120 after the diebonding is finished. Both the materials and the electro-magnet design are not limited to one solution or a few. The magnetic switching of the master sample (apparatus 130), e.g. in this case it can be a ferromagnet, can be implemented by a local heating, e.g. a laser beam can generate heating on the master sample 130 to elevate the sample temperature slightly above the Curie temperature. In this way, the master sample 130 can become weakly paramagnetic and thus it can be detached from the top surfaces of the two samples 110, 120. After that, the master sample 130 can be magnetically initialized in an external magnetic field.

[0146] Figure 3 shows a passive alignment system 300 for vertical alignment of at least two elements 110, 120 according to an embodiment. Such a passive alignment system 300 (here also referred to as a multiple element arrangement) comprises multiple elements 110, 120 as described above with respect to Figures 1 and 2a, 2b, 2c and a base element 140, e.g., a substrate (not shown in Figure 3 but shown in Figures 4a / b / c).

[0147] The multiple element arrangement 400b, 400c (as shown in Figures 4a / b / c) comprises: a base element 140: a first element 110 of a plurality of elements 110, 120, 150 attached to the base element 140, the first element 110 comprising a reference feature 111 and a first magnet pattern 112 which is aligned with the reference feature 111 of the first element 110. The multiple element arrangement 400b, 400c comprises a second element 120 of the plurality of elements 110, 120, 150 attached to the first element 110, the second element 120 comprising a reference feature 121 and a second magnet pattern 123 which is aligned with the reference feature 121 of the second element 120 as described above with respect to Figures 1 , 2a, 2b, 2c.

[0148] The second element 120 is attached to the first element 110 by magnetic force between the first magnet pattern 112 of the first element 110 and the second magnet pattern 123 of the second element 120 such that both magnet patterns 112, 123 are aligned with respect to each other and thus the reference feature 111 of the first element 110 is aligned to the reference feature 121 of the second element 120.

[0149] The above elements 110, 120, 150 that are aligned with respect to each other can be semiconductor chips, for example, or other elements like PCBs, photodiodes, coils, vapor cells, optical waveguides, etc. or any combination of such elements. They can be active elements and / or passive elements.

[0150] Although the multiple element arrangement can comprise just two elements, it is understood that the scope is not limited to just two elements. There can exist 3, 4, 5 and more elements that are aligned with respect to each other by magnetic force of their magnet patterns as the wording “of a plurality of elements” indicates.

[0151] The multiple element arrangement thus can form a stack of elements which are stacked above each other such that their reference features are aligned with respect to each other.

[0152] The multiple element arrangement 400c may comprise: a third element 150 as shown in Figure 4c of the plurality of elements 110, 120, 150 attached to the second element 120. The third element 120 comprises a reference feature 151 and a second magnet pattern 153 which is aligned with the reference feature 151 of the third element 150.

[0153] The second element 120 may comprise a first magnet pattern 122 which is aligned with the reference feature 121 of the second element 120.

[0154] The third element 150 may be attached to the second element 120 by magnetic force between the first magnet pattern 122 of the second element 120 and the second magnet pattern 153 of the third element 150 such that both magnet patterns 122, 153 are aligned with respect to each other and thus the reference feature 151 of the third element 150 is aligned to the reference features 111, 121 of the first and second elements 110, 120. In one example, the first element 110 may be attached to the base element 140 by a bonding layer 141, as shown in Figure 4a, for example. The second element 120 may be attached to the first element 110 additionally to the magnetic force by a second bonding layer 142 as shown in Figures 4b and 4c.

[0155] In one exemplary implementation, the multiple element arrangement can be produced by the following steps:

[0156] 1. die-bonding chip 1 on the substrate;

[0157] 2. stack chip 2 on chip 1 by magnetic mating and die-bonding them;

[0158] 3. stack chip 3 on chip 2 by magnetic mating and die-bonding them;

[0159] N. stack chip N on chip (N-l) and die-bonding them.

[0160] Figures 4a, 4b and 4c show a method for vertical alignment of at least two elements 110, 120 with die bonding first element 110 on substrate 400a (Figure 4a), die bonding 400b second element 120 on first element 110 (Figure 4b) and die bonding N- 1thelement on N111element 400c (Figure 4c) according to an embodiment.

[0161] Figures 4a, 4b and 4c also show main steps to perform magnetic mating elements 110, 120, 150 along the vertical direction with a die-bonding process on a substrate 140.

[0162] The method for producing a multiple element arrangement 400b, 400c comprising a base element 140 and a plurality of elements 110, 120, 150 comprise the following items:

[0163] Attaching a first element 110 of the plurality of elements 110, 120, 150 to the base element 140, the first element 110 comprising a reference feature 111 and a first magnet pattern 112 which is aligned with the reference feature 111 of the first element 110; and

[0164] Attaching a second element 120 of the plurality of elements 110, 120, 150 to the first element 110, the second element 120 comprising a reference feature 121 and a second magnet pattern 123 which is aligned with the reference feature 121 of the second element 120; wherein the second element 120 is attached to the first element 110 by magnetic force between the first magnet pattern 112 of the first element 110 and the second magnet pattern 123 of the second element 120 such that both magnet patterns 112, 123 are aligned with respect to each other and thus the reference feature 111 of the first element 110 is aligned to the reference feature 121 of the second element 120.

[0165] The method may further comprise: attaching a third element 150 of the plurality of elements 110, 120, 150 to the second element 120, the third element 120 comprising a reference feature 151 and a second magnet pattern 153 which is aligned with the reference feature 151 of the third element 150; wherein the second element 120 comprises a first magnet pattern 122 which is aligned with the reference feature 121 of the second element 120; wherein the third element 150 is attached to the second element 120 by magnetic force between the first magnet pattern 122 of the second element 120 and the second magnet pattern 153 of the third element 150 such that both magnet patterns 122, 153 are aligned with respect to each other and thus the reference feature 151 of the third element 150 is aligned to the reference features 111, 121 of the first and second elements 110, 120. Performing the passive alignment by magnetic-mating as described above results in a high accuracy (<100 nm) and a high speed compared to existing passive alignment technique described in the beginning of this disclosure. Passive alignment by magnetic-mating allows to perform batch operation by means of multi-master sample heads for multi die-bonding tasks.

[0166] When achieving the magnetic mating from the top surfaces, the height difference of two samples which need to be aligned along the in-plane direction is not needed to be compensated.

[0167] In this disclosure, a new method to perform die-bonding was presented. Any products which require a packaging process of die-bonding, including packaging processes of active alignment and passive alignment, can benefit from this novel solution presented in this disclosure. Specially the following products or modules of optics communications can be applied for the inplane alignment geometry as introduced in this disclosure: ROSA, TOSA, SOA in GPON and long-haul optical systems, for example. A good example, inter aha, for the vertical alignment geometry is the assembly for the chip-scale atomic clock.

[0168] While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise". Also, the terms "exemplary", "for example" and "e.g." are merely meant as an example, rather than the best or optimal. The terms “coupled” and “connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless whether they are in direct physical or electrical contact, or they are not in direct contact with each other.

[0169] Although specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.

[0170] Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

[0171] Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the disclosure beyond those described herein. While the disclosure has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the disclosure. It is therefore to be understood that within the scope of the appended claims and their equivalents, the disclosure may be practiced otherwise than as specifically described herein.

Claims

CLAIMS:

1. An apparatus (130) for alignment of at least two elements (110, 120), the apparatus (130) comprising: a first magnet pattern (132) configured to attract a first magnet pattern (112) of a first element (110) of the at least two elements (110, 120), which is aligned with a reference feature (111) of the first element (110), by magnetic force (134) such that both magnet patterns (112, 132) are aligned with respect to each other; and a second magnet pattern (133) configured to attract a first magnet pattern (122) of a second element (120) of the at least two elements (110, 120), which is aligned with a reference feature (121) of the second element (120), by magnetic force (135) such that both magnet patterns (122, 132) are aligned with respect to each other and thus the reference feature (111) of the first element (110) is aligned to the reference feature (121) of the second element (120).

2. The apparatus (130) of claim 1 , wherein the first magnet pattern (132) of the apparatus (130) is configured to attract the first magnet pattern (112) of the first element (110) by a magnetic force (134) that is strong enough to overcome a weight of the first element (110); and wherein the second magnet pattern (133) of the apparatus (130) is configured to attract the first magnet pattern (122) of the second element (120) by a magnetic force (135) that is strong enough to overcome a weight of the second element (120).

3. The apparatus (130) of claim 1 or 2, wherein the reference feature (111) of the first element (110) comprises a critical area and the reference feature (121) ofthe second element (120) comprises a critical area; and wherein the apparatus (130) is configured to align the critical area ofthe first element (110) to the critical area of the second element (120).

4. The apparatus (130) of claim 3, wherein the critical area of the first element (110) comprises a first optical or photonic component and the critical area of the second element (120) comprises a second optical or photonic component; and wherein the apparatus (130) is configured to align the optical or photonic component of the first element (110) to the optical or photonic component of the second element (120).

5. The apparatus (130) of any ofthe preceding claims, wherein each of the two elements (110, 120) comprises a first main surface (110a, 120a), a second main surface (110b, 120b) opposite to the first main surface (110a, 120a) and one or more side surfaces (110c, 1 lOd, 120c, 120d) between the first main surface (110a, 120a) and the second main surface (110b, 120b); and wherein the apparatus comprises a first main surface (130a), a second main surface (130b) opposite to the first main surface (130a) and one or more side surfaces (130c, 130d) between the first main surface (130a) and the second main surface (130b); wherein the first main surfaces (110a, 120a) of the two elements (110, 120) are facing the second main surface (130b) of the apparatus when the two elements (110, 120) are attracted to the apparatus (130).

6. The apparatus (130) of claim 5, wherein the reference feature (111) of the first element (110) is arranged at a first surface (1 lOd) of the first element (110); wherein the reference feature (121) of the second element (120) is arranged at a second surface (120e) of the second element (120); and wherein the first and second magnet patterns (132, 133) of the apparatus (130) are configured to attract the first magnet patterns (112, 122) of the elements (110, 120) such that the first surface (1 lOd) of the first element (110) faces the second surface (120e) of the second element (120).

7. The apparatus (130) of claim 5 or 6, wherein the reference feature ( 111 ) of the first element ( 110) is aligned to the first main surface ( 110a) of the first element (110);wherein the reference feature ( 121 ) of the second element ( 120) is aligned to the first main surface (120a) of the second element (120); such that the reference feature (111) of the first element (110) is aligned to the reference feature (121) of the second element (120) independently of a thickness difference between the first element (110) and the second element (120).

8. The apparatus (130) of any of the claims 5 to 7, wherein the magnet patterns (132, 133) of the apparatus (130) are arranged along the second main surface (130b) of the apparatus (130).

9. The apparatus (130) of any of the preceding claims, wherein the magnet patterns (132, 133) of the apparatus (130) are facing the magnet patterns (112, 122) of the first and second elements (110, 120) in order to initiate the magnetic forces (134, 135) attracting the first and second elements (110, 120) to the apparatus (130); and wherein a geometric shape of the magnet patterns (132, 133) of the apparatus (130) corresponds to a geometric shape of the magnet patterns (112, 122) of the first and second elements (110, 120).

10. The apparatus (130) of claim 9, wherein the geometric shape of the magnet patterns (132, 133) of the apparatus (130) forms two or more parallel stripes or any other geometrical figure.

11. The apparatus (130) of any of the preceding claims, comprising: a switch (131) configured to control a magnetization of the first and second magnet patterns (132, 133) of the apparatus (130) for an attraction, a repulsion or a negligible interaction of the magnet patterns (112, 122) of the first and second elements (110, 120).

12. The apparatus (130) of claim 11 , wherein the switch (131) comprises an electro-magnet configured to increase or decrease the magnetic forces (134, 135) of the magnet patterns (132, 133) of the apparatus (130); and / or wherein the switch (131) comprises a heating source configured to heat the magnet patterns (132, 133) of the apparatus (130) above their Curie temperatures in order to mitigate the magnetic forces (134, 135) of the magnet patterns (132, 133) of the apparatus (130).

13. An element (110), comprising: a reference feature (111); and a first magnet pattern (112) which is aligned with the reference feature (111); wherein the first magnet pattern (112) is configured to be attracted by a first magnet pattern (132) of an apparatus (130) according to any of the preceding claims such that the first magnet pattern (112) of the element (110) is aligned with the first magnet pattern (132) of the apparatus (130) and the reference feature (111) of the element (110) is aligned with a reference feature (121) of a second element (120) which first magnet pattern (122) is aligned with the reference feature (121) of the second element (120) and attracted by a second magnet pattern (133) of the apparatus (130).

14. The element (110) of claim 13, wherein a geometric shape of the first magnet pattern (112) of the element (110) spatially mirrors with a geometric shape of the first magnet pattern (132) of the apparatus (130).

15. The element (110) of claim 13 or 14, wherein the element (110) comprises a first main surface (110a), a second main surface (110b) opposite to the first main surface (110a) and one or more side surfaces (110c, 1 lOd) between the first main surface (110a) and the second main surface (110b); and wherein the apparatus (130) comprises a first main surface (130a), a second main surface (130b) opposite to the first main surface (130a) and one or more side surfaces (130c, 130d) between the first main surface (130a) and the second main surface (130b);wherein the first main surface (110a) of the element (110) is facing the second main surface (130b) of the apparatus (130) when the element (110) is attracted by the apparatus (130).

16. The element (110) of claim 15, wherein the reference feature (111) of the element (110) is arranged at a first surface (1 lOd) of the element (110); and wherein the first magnet pattern (132) of the apparatus (130) is configured to attract the first magnet pattern (112) of the element (110) such that the first surface (1 lOd) of the element (110) faces a second surface (120e) of the second element (120) at which the reference feature (111) of the second element (120) is arranged.

17. The element (110) of claim 15 or 16, wherein the reference feature (111) of the element (110) is aligned to the first main surface (110a) of the element(110); such that the reference feature (111) of the element (110) is aligned to the reference feature (121) of the second element (120) independently of a thickness difference between the element (110) and the second element (120).

18. The element (110) of any of the claims 13 to 17, wherein the first magnet pattern (112) of the element (110) is arranged along the first main surface (110a) of the element (110).

19. The element (110) of any of claims 13 to 18, wherein the first magnet pattern (112) of the element (110) is arranged to spatially mirror with the first magnet pattern (132) of the apparatus (130).

20. A method for aligning a first element with a second element, the method comprising: attracting (200a) a first magnet pattern (112) of a first element (110), which is aligned with a reference feature(111) of the first element (110), by magnetic force (134) with a first magnet pattern (132) of an apparatus (130) according to any of claims 1 to 13 such that both magnet patterns (112, 132) are aligned with respect to each other; and attracting (200a) a first magnet pattern (122) of a second element (120), which is aligned with a reference feature (121) of the second element (120), by magnetic force (135) with a second magnet pattern (133) of the apparatus (130) such that both magnet patterns (122, 132) are aligned with respect to each other and thus the reference feature (111 ) of the first element (110) is aligned to the reference feature (121) of the second element (120).

21. The method of claim 20, wherein the first magnet pattern (112) of the first element (110) and the first magnet pattern (122) of the second element (120) are simultaneously or nearly simultaneously attracted by the apparatus (130).

22. The method of claim 21 , comprising : attaching (200b) the first element (110), attracted to the first magnet pattern (132) of the apparatus (130), and the second element (120), attracted to the second magnet pattern (133) of the apparatus (130), onto a base element (140) by using a bonding layer (141).

23. The method of claim 22, comprising: mitigating or reversing (200c) the magnetic forces (134, 135) of the first and second magnet patterns (132, 133) of the apparatus (130) to remove the first and second elements (110, 120), which are attached to the base element (140), from the apparatus (130).

24. A multiple element arrangement (400b, 400c), comprising: a base element (140); a first element (110) of a plurality of elements (110, 120, 150) attached to the base element (140), the first element (110) comprising a reference feature (111) and a first magnet pattern (112) which is aligned with the reference feature (111) of the first element (110); and19a second element (120) of the plurality of elements (110, 120, 150) attached to the first element (110), the second element (120) comprising a reference feature (121) and a second magnet pattern (123) which is aligned with the reference feature (121) of the second element (120); wherein the second element (120) is attached to the first element (110) by magnetic force between the first magnet pattern (112) of the first element (110) and the second magnet pattern (123) of the second element (120) such that both magnet patterns (112, 123) are aligned with respect to each other and thus the reference feature (111) of the first element (110) is aligned to the reference feature (121) of the second element (120).

25. The multiple element arrangement (400c) of claim 24, comprising: a third element (150) of the plurality of elements (110, 120, 150) attached to the second element (120), the third element (120) comprising a reference feature (151) and a second magnet pattern (153) which is aligned with the reference feature (151 ) of the third element (150); wherein the second element (120) comprises a first magnet pattern (122) which is aligned with the reference feature (121) ofthe second element (120); wherein the third element (150) is attached to the second element (120) by magnetic force between the first magnet pattern (122) ofthe second element (120) and the second magnet pattern (153) ofthe third element (150) such that both magnet patterns (122, 153) are aligned with respect to each other and thus the reference feature (151 ) of the third element (150) is aligned to the reference features (111, 121) of the first and second elements (110, 120).

26. The multiple element arrangement (400b, 400c) of claim 24 or 25, wherein the first element (110) is attached to the base element (140) by a bonding layer (141).

27. The multiple element arrangement (400b, 400c) of claim 26, wherein the second element (120) is attached to the first element (110) additionally to the magnetic force by a second bonding layer (142).

28. A method for producing a multiple element arrangement (400b, 400c) comprising a base element (140) and a plurality of elements (110, 120, 150), the method comprising: attaching a first element (110) of the plurality of elements (110, 120, 150) to the base element (140), the first element (110) comprising a reference feature (111) and a first magnet pattern (112) which is aligned with the reference feature (l l l) ofthe first element (110); and attaching a second element (120) of the plurality of elements (110, 120, 150) to the first element (110), the second element (120) comprising a reference feature (121) and a second magnet pattern (123) which is aligned with the reference feature (121) of the second element (120); wherein the second element (120) is attached to the first element (110) by magnetic force between the first magnet pattern (112) of the first element (110) and the second magnet pattern (123) of the second element (120) such that both magnet patterns (112, 123) are aligned with respect to each other and thus the reference feature (111) ofthe first element (110) is aligned to the reference feature (121) of the second element (120).

29. The method of claim 28, comprising: attaching a third element (150) ofthe plurality of elements (110, 120, 150) to the second element (120), the third element (120) comprising a reference feature (151) and a second magnet pattern (153) which is aligned with the reference feature (151 ) of the third element (150); wherein the second element (120) comprises a first magnet pattern (122) which is aligned with the reference feature (121) ofthe second element (120); wherein the third element (150) is attached to the second element (120) by magnetic force between the first magnet pattern (122) ofthe second element (120) and the second magnet pattern (153) ofthe third element (150) such that both magnet patterns (122, 153) are aligned with respect to each other and thus the reference feature (151) of the third element (150) is aligned to the reference features (111, 121) of the first and second elements (110, 120).20

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