Method for bonding a first substrate to a second substrate, device for bonding and device comprising a first and a second substrate

Abstract

The invention relates to a method for joining a first substrate (2u) to a second substrate (2o), the first substrate (2u) having a primary section and the second substrate (2o) having a secondary section, a joining wave (3) being formed between a first sub-section and a second sub-section during joining of the first substrate (2u) to the second substrate (2o), said joining wave advancing in a joining direction, the first substrate (2u) and the second substrate (2o) are connected in the first sub-section, and the first substrate (2u) and the second substrate (2o) are still to be connected in the second sub-section, a sub-region of the second substrate (2o) in the second sub-section is highly offset with respect to a sub-region of the second substrate (2o) in the first sub-section in a direction running perpendicular to the main extension plane, and wherein the primary section and the secondary section are oriented relative to each other, in particular with respect to a direction running substantially parallel to the joining direction, the first curvature of the first substrate (2u) and / or the second curvature of the second substrate (2o) is modified by means of a deformation system in a region adjacent to and / or comprising the bonding wave (3).

Description

Technical Field

[0001] The present invention relates to a method for bonding a first substrate to a second substrate, an apparatus for bonding and a device consisting of the first and second substrates. Background Art

[0002] In the semiconductor industry, there are many different methods for connecting substrates, especially wafers, to each other. The connection process is called bonding. The bonding process can be performed temporarily or permanently. Temporary bonding is usually only used to bond a product substrate to a carrier substrate so that it can be processed. Permanent bonding is used to permanently connect two substrates. The substrate to be bonded is preferably a product substrate. Each product substrate usually already has a structure, especially a complete functional unit, such as a microchip, a memory chip, an LED, a MEMS, etc. By permanent bonding, product substrates with different functional units can be combined into a substrate stack.

[0003] For example, it is conceivable that there are a plurality of microchips on a first product substrate and a plurality of memory chips on a second product substrate. By means of a corresponding design of the functional units on the two product substrates, it is possible that each microchip is associated with a memory chip. The connection of the functional units beyond the bonding boundary surface is preferably carried out across the contact boundary surfaces of the two vias. Since the substrate surfaces are directly connected to each other, it is also referred to as direct bonding. A special form of direct bonding is fusion bonding. Fusion bonding is a direct bonding of dielectric substrate surfaces, in particular substrate surfaces consisting of oxides.

[0004] A particularly important fusion bonding is hybrid bonding. Hybrid bonding is understood as bonding between two substrate surfaces consisting of electrical regions and dielectric regions. Dielectric regions are mostly oxides, especially silicon oxide. Silicon oxide is opened at multiple locations through different process steps. The openings are mostly radially symmetrical openings. These openings are then filled with metal. The metal extends to the functional units buried under the dielectric layer and is a contact extending outward. After the manufacturing process, a substrate surface consisting of a mainly dielectric region and multiple small distributed electrical regions is left. Multiple such substrates can then be oriented relative to each other and contact each other through hybrid bonding. Here, it is fundamentally important that the metal regions are correctly in contact with each other, because otherwise electrical contact between functional elements cannot be achieved. The metal region is called a via (English: via, plural: vias). If the via also passes through silicon, then the via is usually called a silicon via (English: TSVs, through-silicon-vias). The surface of the via is the most important type of structure that must remain consistent in the fusion bonding process, because electrical contact of different functional elements is made through it.

[0005] As fusion bonding, especially hybrid bonding, is increasingly used to produce "next generation" semiconductor chips, there is a need to continuously improve the quality of the bonding results. The main quality criterion for the substrates used for bonding is the accuracy of the orientation of the structures, especially the through-holes. This is called "overlay". In principle, this refers to the actual orientation of the structure relative to the expected orientation of the structure.

[0006] The entire semiconductor industry produces structures whose structural sizes are in the micrometer range and currently already in the nanometer range. Transistors, for example, have structural sizes in the nanometer range. TSVs can have structural sizes in the micrometer range. Entire microchips have structural sizes in the millimeter or micrometer range.

[0007] All structures are developed with the aid of software and stored digitally. This means that each structure produced on the substrate in the subsequent manufacturing process first has a precisely defined position and size in the computer. This idealized state is referred to below as the desired state.

[0008] In order to produce a structure on a substrate, dozens, sometimes even hundreds of process steps are required. Each process step can usually only be performed with a certain accuracy or is subject to errors. Thus, for example, the diffraction limit is a typical example of the maximum achievable accuracy in lithography when the structure of a mask is to be transferred into a photoresist. Although the physical limits can be exhausted, they cannot be avoided. A typical example of a process with errors is the gap in a mechanical engineering element that has to perform a movement. Mechanical components cannot be constructed without gaps, so that some type of error will always occur, which ultimately has an impact on the accuracy of the manufactured structure.

[0009] Although great progress has been made in recent decades to produce structures on substrates with increasing precision, while at the same time the surface density of said structures is constantly increasing, it is a fact that each produced structure on a substrate usually deviates from the desired state, even if only to a very small extent. Said actually existing state of the structure on the substrate is referred to as the actual state hereinafter.

[0010] However, the term "Overlay" is still more commonly used in the semiconductor industry. Overlay is generally understood as a set of displacement vectors of individual points of a substrate, which represent the displacement of a point from a position before a method step to a position after the method step. Therefore, each individual method step of the method may result in a displacement of the structure and thus an alignment accuracy. In this context, the state before the method step is referred to as the desired state, and the state after the method step is referred to as the actual state.

[0011] Therefore, the structure of two substrates to be bonded to one another is usually not ideal even before the bonding process but is distorted with respect to the desired state.

[0012] Another much more serious problem occurs during the joining process. The joining process is carried out by the expansion of the joining wave in the fusion joining. The substrates are initially contacted in a point-like manner, especially in the center. Then, at least one of the two substrates moves so that the joining surface between the two substrates can be enlarged and expanded. It is conceivable that the upper substrate falls, especially in a controlled manner, or the fixing elements of the upper substrate holder are continuously switched, especially from the inside to the outside, so that the upper substrate falls from the contact point toward the periphery. It is also conceivable that the two substrate holders and thus the substrates are close to each other. A combination of the mentioned possibilities is also conceivable. In any case, the joining wave advances outward from the contact point. During the joining process, multiple competing forces are formed, especially along the joint. The forces cause distortion of the lower and / or upper substrates during the advancement of the joining wave, thereby causing undesirable deviations between the upper and lower substrates, especially the functional units. Even if the structure is manufactured in the desired state (which is technically impossible or only very difficult to achieve), the joining process will lead to new distortions.

[0013] Another problem is that the distortions produced by the joining process may not necessarily have an effect only locally, but rather globally. Each distortion at an inner radial position of the substrate generally also has an effect on the joining result at a radial position located further outward.

[0014] Another problem is so-called edge defects (English: edge voids). These micrometer to millimeter-sized defects, which may be gas inclusions, have been a known and disturbing problem in the semiconductor industry for many years. The generation of edge defects is still a very intensively studied phenomenon in technology, and avoiding them is a desirable goal.

[0015] Another problem is the increased distortion at the edges of the substrate. Although distortion generally occurs along the entire substrate surface during the bonding process, distortion is particularly strong at the edges. Summary of the invention

[0016] Based on this, the object of the present invention is to avoid the disadvantages known from the prior art or to reduce their influence on the joining process and the products to be joined.

[0017] The invention achieves the object by means of a method for joining a first substrate to a second substrate according to claim 1 and by means of a device for joining according to claim 7 and a device according to claim 15. Advantageous improvements of the invention are described in the dependent claims. All combinations of at least two of the features described in the specification, in the claims and / or in the drawings fall within the scope of the invention. In the numerical ranges described, the values ​​within the mentioned limits should also be regarded as disclosed as limit values ​​and can be protected in any combination. As long as the features are described in the specification and claims for the first substrate and the first substrate holder, these features apply similarly to the second substrate and the second substrate holder.

[0018] According to a first aspect of the present invention, a method for joining a first substrate to a second substrate is provided, wherein the first substrate has a primary section and the second substrate has a secondary section, wherein when joining the first substrate to the second substrate,

[0019] a first subsection in which the first substrate and the second substrate are connected, and

[0020] --A second sub-section, in which a joining wave advancing along the joining direction is formed between the first substrate and the second substrate to be connected, wherein preferably, a sub-region of the second substrate in the second sub-section is highly offset relative to a sub-region of the second substrate in the first sub-section in a direction extending perpendicular to the main extension plane, and wherein for the relative orientation of the primary section and the secondary section with respect to each other, in particular with respect to a direction extending essentially parallel to the joining direction, the first curvature of the first substrate and / or the second curvature of the second substrate is modified in an area adjacent to the joining wave and / or in an area including the joining wave by means of a deformation system.

[0021] In contrast to the methods known from the prior art, it is proposed according to the invention that, in particular directly before the region adjacent to the joining wave is joined, in the region adjacent to the joining wave or in the region including the joining wave, the first curvature and / or the second curvature are modified locally in a targeted manner. In particular, it is proposed that a corresponding adjustment is made by modifying the first curvature and / or the second curvature, which adjustment ensures that after the joining process, the primary section and the secondary section are arranged one above the other, preferably superimposed on each other, in a direction extending perpendicularly to the main extension plane. In other words, the precise alignment is optimized. In this way, it is advantageously possible to increase the positioning accuracy, which ensures that the primary section and the secondary section of the first substrate and the second substrate are not offset from each other in a direction extending parallel to the joining direction. This is particularly advantageous in the case where structural and / or functional elements are respectively formed in the primary section and the secondary section, which should be connected to each other, in particular electrically connected, in the joined state. These structural and / or functional units, for example, contain vias and / or terminals of electrical or electronic components, such as MEMS or LEDs.

[0022] It has been shown that by setting the first and / or second curvature in a targeted manner, in particular in an area adjacent to or including the joining wave, it is possible to control the position accuracy, in particular the relative orientation of the primary section and the secondary section, so that the probability of exclusion is significantly reduced. If the primary section and the secondary section are offset from each other so that, for example, a sufficient connection cannot be achieved between the primary section and the secondary section or between corresponding functional units in the primary section and the secondary section, such exclusion of the device formed by the first and second substrates is performed. In particular, it is proposed that the first or second curvature is influenced in a targeted manner in an area adjacent to and / or including the joining wave, that is, in a targeted manner in a locally delimited area. In particular, it is proposed that the first or second curvature is influenced locally in a targeted manner. In addition, an overall or overall effective deformation can be provided. Preferably, the deformation system is used to influence only the first substrate or the second substrate, that is, only one of the substrates to be joined. As a result, the number of parameters to be controlled and monitored is advantageously reduced and limited to the operation of a single substrate.

[0023] In particular, it is proposed that the modification of the first and / or second curvature is used to adapt the first curvature and the second curvature to one another in the region adjacent to the joining wave. It is conceivable, for example, that the difference between the first curvature and the second curvature should not exceed a specified threshold value or remain essentially constant. The curvature is to be understood in particular as the reciprocal value of the radius of a circle whose section describes a curved subregion of the first substrate or the second substrate.

[0024] The bonding between the first substrate and the second substrate takes place here via substrate surfaces of the first substrate and the second substrate which are in contact with one another during the bonding, ie during the bonding process or bonding technology.

[0025] The main extension plane is preferably determined by the supporting surface of the substrate holder, i.e. the first substrate holder and / or the second substrate holder. The supporting surface preferably extends along the main extension plane with its overall extension. In particular, the main extension plane is determined by the overall extension of the first subsection, in particular by the overall extension of the region of the first subsection that is not bent or has no curvature and extends essentially flat.

[0026] The joining process is characterized in particular in that, during joining, the first subsection that has been joined is basically arranged in the main extension plane, while the first substrate and / or the second substrate are at least partially offset in height in the second subsection relative to the first subsection in a direction extending perpendicular to the main extension plane. In particular, it is proposed that, during joining, the first substrate is lifted in sections in the area adjacent to the joining wave. The second substrate also has a second curvature in the area adjacent to the joining wave by being spaced apart from the second substrate holder. As a result, the first curvature and the second curvature are already obtained in the area of ​​the joining wave by the joining process, and the deformation system does not exert an influence on the first curvature or the second curvature. Therefore, the modification or the scope of the modification from the deformation system is determined with respect to the first curvature and / or the second curvature as follows, and the first curvature and / or the second curvature should be determined during the joining process without the deformation system.

[0027] In particular, the region adjacent to or including the joining wave extends over a range of at least 5 mm, preferably at least 2.5 mm and particularly preferably at least 1 mm. It is preferably provided that, outside the region dimensioned in this way, the deformation or modification and effect on the first curvature by the deformation section or the deformation system or the fixing element is negligibly small. The region adjacent to or including the joining wave can extend over the range of the first subregion and the second subregion.

[0028] Preferably, the bonding is direct bonding, preferably fusion bonding and particularly preferably hybrid bonding.The substrate is preferably a wafer, for example a silicon wafer, which is particularly preferably bonded by bonding as a product substrate or a temporary substrate.

[0029] The first curvature and / or the second curvature are preferably set by means of a deformation system, which includes a coating, a fixing element and / or a deformation mechanism. Those skilled in the art will particularly understand the fixing element as the following device, which is set to hold a sub-segment of the first and / or second substrate. Preferably, each fixing element can be transformed between a fixed state and a released state individually or in groups. The fixing element is used to contact the sub-regions of the first substrate and the second substrate in a targeted manner in the bonding process. For example, each fixing element in the second substrate holder is transformed into a released state so that the sub-region of the second substrate falls, so as to contact the corresponding sub-region of the first substrate in this way. The first curvature can also be affected by setting the fixing force in a targeted manner. In a preferred embodiment, the deformation system is at least partially or completely formed by a fixing element. It is also conceivable that the deformation mechanism is preferably only designed to set the first curvature and / or the second curvature and, for example, cannot fix or hold the first substrate and / or the second substrate in order to control the bonding process.

[0030] The skilled person in the art will preferably understand structure as any form of the following object, which is manufactured on a substrate by means of different processes. Examples of structures are transistors, the smallest unit of TSV, but also the functional unit defined below. Therefore, the word structure is used as a general concept. The skilled person in the art will especially understand the functional unit as the following structure, which has functional characteristics and can therefore be regarded as an active part. Examples of this are microchips, memory chips, LEDs, MEMS, etc. The skilled person in the art will especially understand displacement as a change in the position of a point from a first position to a second position. The skilled person in the art will preferably understand distortion or expansion as a change in length with respect to the initial length in physical terms. Observed mathematically, the distortion or expansion is a partial derivative of the displacement. The skilled person in the art will understand stretching as the extension of the body due to distortion or expansion. The skilled person in the art will understand the desired state as an idealized, especially computer-generated, calculated and stored set of all structures with their ideal positions or a set of all structures before the method step. The skilled person in the art will preferably understand the actual state as an actual, especially a set of all structures with their actual positions that have been generated at the substrate or a set of all structures after the method step. A person skilled in the art understands fine alignment in particular as the magnitude of the vector displacement of a structure from a first process step to a second process step. Fine alignment is usually shown as a displacement vector field. Each structure on the substrate can be associated with a position for the first process step and for the second process step. The displacement is the vector difference of these two positions and the displacement vector field or fine alignment is the set of all these vector differences for all structures.

[0031] The person skilled in the art preferably understands a substrate holder as any component, in particular any component group, by means of which a substrate is fixed and by means of which a bonding wave advancing forward can be manipulated. A bonding wave is understood to be the set of all boundary surface points of two substrates connected to one another, which separate an outer area that has not yet been bonded from an inner area that has already been bonded. Synonyms for a bonding wave (or bond wave) are a bonding boundary surface or a bonding front.

[0032] Preferably, the modification of the first curvature and / or the second curvature is performed via fixing elements. A plurality of all substrate holders already have corresponding fixing elements. There are also substrate holders which have a plurality of fixing elements, which are particularly symmetrically distributed, so that position-controlled fixing of substrates, i.e. the first substrate and / or the second substrate, is possible. By means of targeted control of the fixing elements, in particular before and / or during and / or after the joining wave passes through the fixing elements, the expansion or bending caused by the force effect can be set in a targeted manner. If the substrate holder has a plurality of fixing elements distributed on the substrate surface, the joining wave can be controlled in a position-resolved manner.

[0033] It is preferably provided that the deformation system has a plurality of deformation means, which are arranged along the joining direction. By means of a plurality of deformation means, which are particularly evenly distributed along the joining direction, it is advantageously possible to locally influence the first curvature and / or the second curvature during the entire joining process, in particular to influence the first curvature and / or the second curvature in a targeted manner in the respective area to be joined. It is preferably provided that the deformation means and / or measures are arranged substantially equidistant from one another along the joining direction. In the case of radial propagation of the joining wave, for example, the radial spacing between two adjacent deformation means is substantially constant.

[0034] In particular, it is proposed that during the joining, the difference between the first and second curvatures is kept substantially constant at least in sections along the joining direction by means of a deformation system. Preferably, the difference between the first and second curvatures is kept constant in a targeted manner over a section that accounts for more than 50%, preferably more than 75% and particularly preferably more than 80% of the joining section, wherein the joining section represents the entire length over which the joining process is performed. It has been shown that by correspondingly matching the first and second curvatures to one another, the distortion or degree of distortion between the first and second substrates can be kept as small as possible, which advantageously affects the possible tension between the first substrate and the second substrate and the positional accuracy when orienting the first substrate and the second substrate relative to one another. Here, "substantially constant" means that the first curvature and / or the second curvature deviates from twice the arithmetic mean of the first curvature and the second curvature by no more than 15%, preferably no more than 10% and particularly preferably no more than 5%. It is also preferably proposed that, by means of different deformation mechanisms, it is specifically ensured in individual deformation sections along the joining section that the first curvature and the second curvature are substantially constant in their sum. Here, the influence of the individual deformation mechanisms can be different from one another. In particular, the deformation means are individualized with regard to their influence or action for the regions to be respectively engaged and which are associated with the respective deformation means.

[0035] In particular, it is proposed that the deformation system is changed during the joining, for example by means of a control device. For example, it is conceivable to control the influence exerted by each deformation mechanism in the deformation section in a targeted manner so as to exert an influence on the first curvature and / or the second curvature, especially in the joining process. This can be advantageously carried out during the joining process. It is thus possible, for example, to even react to changes occurring during the joining process and to correspondingly adjust the influence exerted for modifying the first and / or second curvature. This can be achieved, for example, preferably by a displaceable component, which can be moved, for example, in a height direction extending perpendicular to the main extension plane. In this case, the corresponding device heights can be set staggered by the control device via corresponding control. It is also conceivable that the coating on the substrate holder can be correspondingly controlled, for example, via a voltage.

[0036] Before and / or during and / or after the passage of the joining wave, the movable component is controlled or regulated so that by raising or lowering the component a new, in particular geometrically changed state is produced for the joining wave or the region adjacent to the joining wave. In particular, convex and / or concave regions can thereby be realized as a function of position. The distortion is thus controlled locally in the substrate so that an optimal joining result is achieved.

[0037] It is preferably provided that the deformation system is set before joining. In particular, the extent to which the first and / or second curvature is influenced in the individual deformation sections is determined in relation to the type of the first and / or second substrate and particularly preferably by corresponding empirical values. In this case, for example, a previous joining process can be used, which can, for example, identify, based on the stress relationships within the arrangement consisting of the first and second substrates, in which regions it is advantageous to adjust the first and second curvatures accordingly during the joining process. In order to understand the behavior, preferably after the joining process, the joined substrates are analyzed in order to determine the displacement between the structures at the lower and upper substrates as a function of the position. With this information, it is possible to modify the substrate surface of the substrate holder, in particular the first substrate holder, so that the behavior of the joining wave at each point provides the desired optimal result. Preferably, the deformation system is then used for a batch of first and second substrates to be joined. For example, the roughness and / or waviness and / or adhesion capacity of the substrate holder can already be taken into account and implemented when producing the substrate holder.

[0038] For example, the method comprises the following steps:

[0039] In a first method step of the method, the first substrate is loaded and fixed to the first substrate holder. In a second method step of the method, the second substrate is loaded and fixed to the second substrate holder. In a third method step of the method, the first substrate is preferably oriented relative to the second substrate, preferably by means of a corresponding optical device. In a fourth method step of the method, the bonding process of the substrate surface of the first substrate with the substrate surface of the second substrate is carried out on the substrate holder. In a fifth method step of the method, the bonded substrate stack is removed from the device. In an optional sixth method step of the method, the substrate stack is subjected to a heat treatment. Here, the modification of the first curvature and / or the second curvature is preferably carried out in the fourth step.

[0040] For the method of determining the degree of influence of the deformation in time before joining, a substrate holder having the device features of a substrate holder with microstructures and / or coatings is particularly suitable. For the method of influencing the first curvature during the joining process, a first substrate holder having a displaceable component has proven to be advantageous. In the following, the individual devices are described in detail.

[0041] It is preferably proposed that, in order to set the first curvature, a coating is provided between the first substrate and the first substrate holder, which carries the first substrate during the joining process. Preferably, as a coating, a layer is deposited at at least one of the two substrates to be joined to each other. The layer is applied to the substrate side opposite to the substrate side to be joined. The substrate side is referred to as the substrate back side. The thickness of the layer is particularly uneven, i.e. varies as a function of position. Preferably, the layer is not applied to the substrate back side over the entire surface, but only at a position specially provided for this purpose, but usually at any position with a thickness provided for this purpose. It is particularly simple to coat the area of ​​the substrate back side that should be coated by using a mask. In a preferred embodiment, the layer is an inorganic layer. The layer is preferably applied by a PVD, CVD or PE-CVD method. It is particularly preferred that, in particular by means of PE-CVD, the deposition of the layer is only in the periphery of the substrate, preferably in a circular segment with a circular segment thickness between 1 mm and 10 mm. The exact circular segment thickness is related to the result to be achieved. The layer should preferably consist of the following material grades, in particular one of the materials mentioned: metal, oxide, preferably SiO 2 , carbide, preferably SiCN, SiC, and / or nitride, preferably SiCN and / or SiN.

[0042] In a particularly preferred embodiment, the inorganic layer is an oxide layer of between 10 nm and 5000 nm. The exact thickness of the oxide layer depends on the result to be achieved. In a refinement of the embodiment, the layer can be thinned back and / or polished after deposition.

[0043] Preferably, a targeted curvature of the substrate is produced by depositing the coating, in particular as a function of position, in particular in the edge region of the substrate. The layer is preferably deposited at elevated temperatures. During cooling, the substrate and the layer usually expand differently, since the thermal expansion coefficients of the substrate and the layer are different. This results in a warp that compensates for the thermal stresses that occur. The warp then also has an effect on the advancing bonding wave during the bonding process.

[0044] Another subject matter of the present invention is a device for joining a first substrate to a second substrate, in particular by means of the method according to the invention, wherein the first substrate has a primary section and the second substrate has a secondary section, wherein the device is configured to, when joining the first substrate to the second substrate,

[0045] a first subsection in which the first substrate and the second substrate are connected, and

[0046] - a second subsection, in which a joining wave is formed between the first substrate and the second substrate to be connected, which wave is advanced along the joining direction, wherein preferably, a subregion of the second substrate in the second subsection is highly offset relative to a subregion of the second substrate in the first subsection in a direction extending perpendicularly to the main extension plane, wherein the device has a deformation system for the relative orientation of the primary section and the secondary section relative to each other, in particular with respect to a direction extending substantially parallel to the joining direction, the deformation system being configured to be able to modify a first curvature of the first substrate and / or a second curvature of the second substrate in a region adjacent to or including the joining wave. All advantages and characteristics described for the method can preferably be applied analogously to the device and vice versa.

[0047] Preferably, the device comprises a first and / or second substrate holder. The substrate holder, ie the first and / or second substrate holder, has a fixing element. The main task of the fixing element is to hold and in particular fix the first substrate and / or the second substrate during the joining process.

[0048] By purposefully releasing the fixing element or by changing the state of the fixing element holding or not holding the substrate, the joining process in the sub-regions of the first substrate and the second substrate can be purposefully set, in particular so that the joining process is formed along the joining direction. The fixing element can be: a mechanical fixing device, in particular a clamp; a vacuum fixing device, in particular a vacuum fixing device with individually controllable vacuum belts and / or vacuum belts connected to each other; an electrical fixing device, in particular an electrostatic fixing device; a magnetic fixing device; an adhesive fixing device, in particular a Gel-Pak fixing device; a fixing device with an adhesive, in particular controllable surface. The fixing element can in particular be electronically controllable.

[0049] A vacuum fixture is a preferred type of fixture. The vacuum fixture preferably comprises a plurality of vacuum belts, which are present at the surface of the substrate holder. The vacuum belts are preferably individually controllable. In a preferred embodiment, some vacuum belts are combined into vacuum belt segments, which are individually controllable and can therefore be evacuated or filled. However, each vacuum segment is independent of the other vacuum segments. Thus, the possibility of constructing a single controllable vacuum segment is obtained. The vacuum segment is preferably constructed in an annular shape. This makes it possible to achieve targeted, radially symmetrical, in particular from the inside to the outside, fixing and / or releasing of the substrate from the substrate holder.

[0050] In particular, it is proposed that the first substrate is held in a first substrate holder during the joining, wherein the first substrate holder has a fixing section for fixing the first substrate and a deformation section for setting the first curvature. At the same time, it is conceivable that the fixing section additionally or alternatively exerts an influence on the first and / or second curvature. This can be achieved, for example, by a fixing force that can be modulated accordingly. It is preferably proposed that the fixing section and the holding section alternate at least in sections along the joining direction, preferably in the range of the entire joining section. It is preferably proposed here that between the two fixing elements, the area in contact with the substrate surface exerts a corresponding influence so that the first and / or second curvature adopts the desired value.

[0051] It is preferably provided that the deformation system has a coating. In particular, it is possible that, when an adhesive or non-adhesive medium is applied to the contact surface in the section between the two fixing elements, the adhesion of the first substrate to the contact surface is influenced in the corresponding region. This in turn has an influence on the first curvature. This occurs in particular if, within the scope of the joining process, the second subsection of the first substrate is lifted relative to the first subsection of the first substrate.

[0052] It is preferably proposed that the adhesion ability of the substrate holder surface is set in a targeted manner as a function of the position by means of the coating, so that the adhesion strength between the substrate and the substrate holder changes as a function of the position. In a particularly preferred embodiment, the adhesion ability is even switchable or regulated in a position-resolvable manner. It is conceivable to use functional polymers, which are modified in the micrometer range and nanometer range so that the lotus effect known from nature can be imitated. Further developments in the research show that the polymer structure is loosened from the object attached thereto by causing the curvature of the polymer structure using an electric field and / or a magnetic field. The loosening of these functional polymers from the substrate can cause the van der Waals force to disappear so that the substrate can be partially loosened. A switchable, adhered substrate holder surface can thus be achieved. Preferably, the coating is applied to the substrate holder. However, it is also conceivable that the coating is applied to the substrate and is arranged between the substrate and the substrate carrier when the device is running.

[0053] Preferably, the deformation system has a microstructure at the contact surface of the first substrate holder. Roughness is thereby achieved at the contact surface. It is conceivable here that the substrate holder surface is structured differently as a function of the position, so that the adhesion strength between the substrate and the substrate holder varies as a function of the position. It is conceivable to produce small holes with different geometries, which vary in size and / or orientation in particular in relation to the position at the substrate holder. The substrate holder can, for example, be coated with a photopolymer, whereby a pattern can be imaged into the photopolymer by means of a photolithographic process. The photopolymer is subsequently developed and stripped off. An etching mask remains. The pattern is subsequently etched into the substrate surface using chemicals and / or plasma. The photopolymer is subsequently removed. A structured substrate surface remains. The pattern is preferably radially symmetrical.

[0054] It is preferably proposed that the deformation system has a displaceable contact surface. This can be done, for example, via a deformation pin, which is supported in a corresponding recess and can be displaced at a corresponding height as required, so as to at least partially support the second sub-segment in this way so that a desired or preferred first curvature and / or second curvature is set. Alternatively, it is conceivable that the displaceable contact surface is formed by segments, into which a plurality of fixing elements are integrated. These displaceable segments can be varied as a whole in a highly movable manner in the substrate holding device. Preferably, the corresponding segments are annularly formed and arranged concentrically with each other. During the joining process, in particular the height of the individual segments is controlled and set, whereby a corresponding influence can be exerted on the first curvature in the area adjacent to the joining wave.

[0055] Preferably, the substrate holder has a dynamic, modifiable substrate holder surface. In one embodiment, the substrate holder is constructed from movable segments. The segments can be centrally positioned circular segments. However, it is also conceivable that the centrally positioned circular segment is again divided azimuthally so that there are a plurality of radially and azimuthally distributed segments. Each of these segments can be moved in a direction normal to the substrate holder surface, thereby influencing the further advancement of the bonding wave.

[0056] In one embodiment, the substrate holder has a controllable or adjustable deformation element, which can be moved out beyond the substrate holder surface. The substrate holder has a plurality of, in particular symmetrically distributed recesses, preferably holes, in which movable deformation elements, in particular pins, are present. These deformation elements can be moved in and out in a controlled or regulated manner so as to cause a local curvature of the substrate fixed to the substrate holder before and / or during and / or after the forward advancement of the bonding wave. Since the deformation elements allow a finer control of the sections than in the previous embodiment, the second embodiment can be more advantageous. In addition, such a substrate holder can be produced more easily and is therefore more economical.

[0057] In a more particular embodiment, the deformation element itself has fixing elements, in particular holes, via which a vacuum can be generated, so that the deformation element can locally fix the substrate lying on the substrate holder and load it both with compressive forces and with tensile forces.

[0058] It is preferably proposed that the deformation system has a contoured contact surface. In particular, each deformation segment has a contoured contact surface. A person skilled in the art understands "contouring" in particular as a concave, convex and / or stepped extension, which can exert an influence on the adhesion and support capacity in this way, which acts from each deformation segment to the first sub-segment and / or the second sub-segment. In another embodiment, it is possible that the substrate holder surface is shaped differently, in particular convexly or concavely, as a function of the position. It is also conceivable that the substrate holder surface obtains a wave degree that changes as a function of the position. Through the shaping, a part of the substrate already exists in a slightly convex or concave shaped manner as a function of the position. Thereby, by purely geometric processing of the substrate holder surface, the influence of the bonding wave that subsequently extends through the substrate holder can be achieved before the bonding process. In another embodiment, the substrate surface has a deviation from flatness at least at the following position, where the substrate has its first contact portion, because in particular the second substrate is pressed onto the first substrate by using bonding pins. Preferably, this involves a recessed portion that is particularly radially symmetrical. Preferably, there is also a fixing element in the area of ​​the recess, which facilitates the fixing of the first substrate. The first substrate is thereby pulled into the recess. Due to the local generation of the curvature, the substrate surface of the first substrate to be joined is compressed at least at its minimum point. It is therefore preferred that a distortion, in particular a compression, is introduced before the joining actually begins. After the joining is completely completed, the fixing element of the first substrate holder is cut off. The first substrate stretches the second substrate, which is already joined, a little. This results in the stretching increasing in the area where the joining wave is just beginning to travel and ideally then becoming the same as the stretching that the second substrate experiences in the area where the joining wave has a stable state. It has been shown that the joining result can be optimized and improved by applying such a distortion before joining.

[0059] It is preferably provided that the deformation sections exert different effects on the first substrate. For example, it is conceivable that in the case of displaceable sections or pin elements, the heights of the individual deformation sections are set differently. In particular, it is provided that the displaceable deformation sections are only displaced during the joining process and are no longer displaced once the joining process has begun.

[0060] In particular, the first substrate holder has a raised portion in the edge region. The raised portion is, for example, configured as a base that is closed over the entire circumference. The structural features are particularly used to eliminate or at least reduce edge defects (English: edge-voids) and distortions that occur at the edges. The raised portion is greater than 10nm, preferably greater than 500nm, more preferably greater than 1000nm, most preferably greater than 2500nm, and most preferably greater than 5000nm. In most cases, the upper substrate of the upper substrate holder is deformed by the bonding pins and contacts the lower substrate. In the deformation process, the substrate surface to be bonded of the second substrate is stretched. Therefore, the second substrate has a convex curvature in a top view of the substrate surface to be bonded of the second substrate. In order to adapt to the stretching now, it is advantageous to compress the substrate surface to be bonded of the first substrate. Therefore, the first substrate has a concave curvature in a top view of the substrate surface to be bonded of the first substrate. The substrate lying flat on the raised portion is thus distorted, especially compressed, in the edge region at its substrate surface to be bonded.

[0061] This is necessary because the deformation of the second substrate towards the edge at the contact point of the bonding wave becomes smaller because of the mechanical resistance of the wafer (due to the shorter remaining unbonded length) and the air can escape more easily from the bonding boundary surface.

[0062] Another subject of the invention is an arrangement consisting of a first substrate and a second substrate, which is produced by means of the method according to the invention. All advantages and properties described for the device and the method can be transferred analogously to the arrangement and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Further advantages and features emerge from the following description of preferred embodiments of the subject matter according to the invention with reference to the accompanying drawings. In this context, individual features of the individual embodiments may be combined with one another within the scope of the invention.

[0064] The accompanying drawings show

[0065] Figure 1 shows a side view of a substrate holder according to a first exemplary embodiment of the present invention;

[0066] Figure 2 shows a side view of a substrate holder according to a second exemplary embodiment of the present invention;

[0067] Figure 3 shows a side view of a substrate holder according to a third exemplary embodiment of the present invention;

[0068] Figure 4 shows a side view of a substrate holder according to a fourth exemplary embodiment of the present invention;

[0069] FIG. 5 shows a side view of the area during the joining process with less tightening; and

[0070] Figure 6 A side view of the area during the joining process is shown with a stronger fastening.

[0071] In the figures, the same reference numerals are used to denote the same components or components with the same function. The figures are to be understood as purely functional and exemplary. The features in the figures are not to scale. In particular, some features are shown exaggeratedly in order to improve the overview and understanding. Correct sectional views are omitted in order to improve the overview. DETAILED DESCRIPTION

[0072] The fixing element 5 in the following description of the figures is, for example and preferably, a vacuum fixing device. The control of the holding force of the substrate can be produced and illustrated here, in particular, intuitively by the strength of the suction force. However, all other types of fixing elements, in particular electrostatic fixing devices, are conceivable.

[0073] Figure 1 A schematic side view of a first embodiment of a substrate holding device 1 is shown, which has a plurality of fixing elements 5, which are particularly arranged in different fixing sections. The substrate holding device 1 is used in a device for joining or connecting a first substrate 2u and a second substrate 2o. Here, the substrate holding device 1 accommodates one of the substrates 2u, 2o to be connected in the operating state. Preferably, the individual fixing elements 5 can be switched between a fixed state and a released state individually or in groups. As a result, it is also possible to advantageously determine a joining direction along which the first substrate 2u and the second substrate 2o are connected to each other. Here, the joining process unfolds along the joining direction, wherein the already joined first subsection and the second subsection to be joined are separated from each other by a joining wave 3. During the joining process, the joining wave 3 moves along the joining direction.

[0074] In addition to the fixing section, the substrate holding device 1 includes a deformation system. The deformation system preferably includes a plurality of deformation sections, in which deformation measures, in particular deformation mechanisms, are respectively provided. The deformation system is preferably designed to set the curvature of the substrates 2u, 2o in a targeted and local area adjacent to the joining wave 3. Here, the adjacent area refers to the area before the joining wave 3, that is, the area to be joined immediately. Preferably, the adjacent area extends in the range of a section of up to 5 mm. Preferably, up to 2.5 mm before the joining section and particularly preferably up to 1 mm. In other words: the deformation system is designed to act locally on a sub-area of ​​the substrates 2a, 2u in a targeted and local manner, which is arranged directly before the joining wave 3. In particular, the deformation system is particularly provided with a deformation section in which the adjacent area is just arranged and which acts on the substrates 2o, 2u in a targeted manner so as to set its curvature before joining. It is preferably proposed that a plurality of deformation sections are formed along the joining direction, which can specifically influence the curvature of the substrates 2o, 2u when the region adjacent to the joining wave 3 reaches the corresponding deformation section during joining. In this way, the curvature of the substrate can be set in a position-dependent manner for each subsection of the substrate to be joined during joining. In one embodiment, the deformation section is formed by a fixing section, in particular when the curvature of the substrate is influenced by means of a fixing element.

[0075] The substrate holder surface 1s of the substrate holder 1 is modified so as to form a modified substrate surface or a modified contact surface 6. The contact surface 6 here comprises a plurality of deformation sections. Figure 1 In the example shown in , deformation sections and fixing sections alternate. For example, it is proposed that the contact surface 6 forms a deformation section between two fixing elements. By means of modifying the contact surface 6, the curvature of the substrates 2o, 2u is then influenced during the joining. In particular, the contact surface 6 is modified in the respective deformation section so that it increases or reduces the adhesion between the contact surface 6 and the substrates 2u, 2o in the deformation section. The modification of the contact surface 6 can also cause a lifting or lowering of a subsection of the substrate.

[0076] The different modifications are shown enlarged below the substrate holder 1 .

[0077] A first modification can be achieved by a coating 10, in particular by a polymer. The coating influences the adhesion strength between the substrate holder 1 and the fixed substrate 2 (not shown), in particular during the forward advance of the bonding wave during the bonding process. The physical properties of the coating 10 can change as a function of position and thus cause a position-resolved influence of the bonding process, in particular in the area adjacent to the bonding wave.

[0078] The second way of modification is a structured substrate surface 11. Depending on the embodiment of the structured substrate surface 11, the fixed substrate 2 (not shown) has more or less contact with the substrate holder 1 and is fixed with greater or less strength. The embodiment should also include the principle of roughness, that is, unevenness occurring in the nanometer range and / or micrometer range.

[0079] The third and fourth ways of modification are a concave curvature 12 and a convex curvature 12'. The curvatures 12, 12' can have different radii of curvature at different positions of the substrate holder 1. If the substrate 2 (not shown) is pulled, for example, by the fixing element 5 to the concave curvature 12, the substrate surface to be joined is compressed. If the substrate 2 (not shown) is placed flat on the convex curvature 12', the substrate surface to be joined is stretched. It becomes possible to set the distortion state in a position-resolved manner. The curvatures 12, 12' are shown in the figures with limited position. However, it is also conceivable that the convex and / or concave curvature extends over a larger range of the substrate holder 1, that is, in particular includes multiple fixing elements 5. It is also conceivable that the entire substrate surface 1s has only one clearly defined concave curvature 12 or convex curvature 12'. In the macroscopic case, it can also be called waviness.

[0080] Figure 2 A schematic side view of a second embodiment of a substrate holder 1 is shown. The substrate holder 1 has a raised portion 13 at its periphery. The raised portion 13 can be embodied, for example, as a base that is closed over the entire circumference. It is also conceivable that a plurality of such separate and mutually separated raised portions 13 are present along a closed curve. The purpose of the raised portion 13 is to slightly raise the substrate 2 (not shown) at the edge. By means of the slight raising, the substrate surface to be joined is distorted, in particular compressed.

[0081] Figure 3 A schematic side view of a third embodiment of a substrate holder 1 is shown. The substrate holder 1 has a plurality of segments 7 which can be moved independently of one another. The centrally located segment 7 is preferably circular. The other segments 7 can be circular segments. It is also conceivable that this involves segments 7 which are also separated from one another in the azimuthal direction.

[0082] Figure 4 A schematic side view of a fourth embodiment of a substrate holder 1 is shown. The substrate holder 1 has a plurality of deformation elements 9 which can be moved into recesses 8, preferably holes. The deformation elements are controllable or manipulable. The fixing element 5 in turn serves to fix the substrate 2 (not shown), while the deformation elements 9 can introduce distortions into the substrate 2 (not shown).

[0083] The two subsequent figures show the physical principle of the joining process as can be realized with the aid of the substrate holder 1 described above. All preferred methods can be attributed to the basic idea that the deviation between the structure of the substrate surface to be joined of the first substrate and the structure of the substrate surface to be joined of the second substrate is minimal in the following case, that is, during the joining process, the advancing joining wave 3 can be influenced so that the occurring distortions 4o, 4u are identical. This object is achieved in particular by setting the distortion 4 in the substrate surface of at least one, preferably the lower substrate. The influence of the distortion 4, in particular the distortion 4u of the first substrate 2u, is more favorable and can be controlled more easily.

[0084] All shown considerations always relate to points of the interface between the two substrates 2u, 2o and are preferably performed for all points of the interface. The shown distortions 4u, 4o relate to the substrate surfaces of the substrates 2u, 2o to be joined, but are shown in the middle of the substrates 2u, 2o for clarity.

[0085] Figure 5a A schematic side view shows a joining process between two substrates 2u, 2o along a forward-moving joining wave 3.

[0086] The lower substrate 2u is loaded and fixed to the lower substrate holder 1u, and the upper substrate 2o is loaded and fixed to the upper substrate holder 1o. The right sub-area of ​​the joining process is shown. The joining wave 3 is only shown as a dot in the side view. The joining wave 3 advances forward from left to right in the side view. It can be seen that the upper substrate 2o is already joined to the lower substrate 2u in the first subsection on the left side, and is still held by the upper substrate holder 1o in the second subsection on the right side.

[0087] As a result, a local lifting of the lower substrate 2u from the lower substrate holder 1u is caused by the force relationships existing around the bonding wave 3. The lower substrate 2u is lifted from the lower substrate holder 1u by only a few nanometers or micrometers, in the worst case by a few millimeters. This local lifting also produces local distortions 4u, 4o in the lower substrate 2u and / or in the lower substrate 2o.

[0088] Figure 5b A schematic side view shows the joining process between two substrates 2u, 2o along a forward-moving joining wave 3, wherein the lower substrate 2u is lifted off the substrate holder 1 more than in FIG. Figure 5aThis is due to the influence of the deformation section, which is exerted on the first curvature. It is conceivable and preferred that the lower substrate 2u is simply prevented from lifting more by the stronger fixing effect of the fixing element 5. This is the easiest method to implement, because almost all substrate holders 1 have fixing elements 5. It is conceivable that the substrate surface has been modified and exerts a greater adhesion effect at this point. It is conceivable that the substrate surface has been coated so that the adhesion effect is greater. Figure 5a In contrast, the lower substrate 2u is not lifted to such an extent from the lower substrate holder 1u, since the corresponding fixing force is stronger. As a result, a smaller distortion 4u is also produced in the lower substrate 2u by the joining process. Generally, the distortion 4o in the upper substrate 2o can also change. In order to better illustrate the joining process, it is assumed that the distortion 4o in the upper substrate 2o does not change or changes only in a negligible manner. As a result, in Figure 5a and Figure 5b A particularly simple comparison of the distorted relationships between them becomes possible.

[0089] Figure 5c A schematic side view shows the joining process between two substrates 2u, 2o along a forward-moving joining wave 3, wherein the lower substrate 2u is lifted off the substrate holder 1 more than in FIG. Figure 5a This is due to the influence of the deformation mechanism, which is exerted on the first curvature. It is conceivable that the lower substrate 2u is subjected to a greater lift simply due to the weaker fixing effect of the fixing element 5, because it can be pulled upwards more easily from the upper substrate 2o. This proves to be a relatively simple possibility for implementing the method, since almost all substrate holders 1 have fixing elements 5. It is conceivable that the substrate surface has been modified and there is a smaller adhesion effect at this point. It is conceivable that the substrate surface has been coated so that the adhesion effect is smaller. Figure 5a In contrast, the lower substrate 2u is not lifted further from the lower substrate holder 1u, since the corresponding fixing force is weaker. As a result, a greater distortion 4u is also produced in the lower substrate 2u by the joining process. Generally, the distortion 4o in the upper substrate 2o can also change. In order to better illustrate the joining process, it is assumed that the distortion 4o in the upper substrate 2o does not change or changes only in a negligible manner. As a result, in Figure 5a and Figure 5c A particularly simple comparison of the distorted relationships between them becomes possible.

[0090] exist Figures 5a to 5cThe right side of the figure also shows again the distortion 4o of the upper substrate and the distortion 4u of the lower substrate. The distortion 4o of the upper substrate is performed with respect to the direction. The distortion 4u of the lower substrate rotates and moves parallel to the tip of the distortion 4o of the upper substrate. The distortion 4u of the lower substrate 2u distorts the structure (not shown) at the lower substrate 2u. However, the same situation occurs through the distortion 4o with the help of the structure (not shown) at the upper substrate 4o. Therefore, the distortion 4r generated is actually defined, which is obtained by the difference between the two distortions 4u and 4o. The distortion 4r generated is not necessarily equivalent to the mechanical distortion in the sense of expansion, but is the magnitude of the deviation of the position of the structure (not shown) between the lower substrate 2u and the upper substrate 2o.

[0091] Figure 6 A schematic side view of the joining process along the advancing joining wave 3 before two substrates 2u, 2o is shown, wherein the joining wave 3 is already very close to the edge of the substrates 2u, 2o. Preferably, the distortion 2u of the lower substrate 2u can be set by the raised portion 13, so that a generated distortion 4r is generated by means of the distortion 4o of the upper substrate, which generated distortion is desired. This embodiment is particularly important in order to eliminate or at least reduce the occurrence of edge defects (English: Edgevoids).

[0092] In practice, it is not possible to completely reduce the distortion 4r that is generated. Preferably, efforts are made to make the distortion 4r that is generated at least uniform, ie, at least of the same magnitude at every location.

[0093] List of reference numerals:

[0094] 1 Substrate holder

[0095] 1u First substrate holding device

[0096] 1o Second substrate holding device

[0097] 1s Substrate holding surface

[0098] 2u First substrate

[0099] 2o Second substrate

[0100] 3 Joint Wave

[0101] 4, 4o, 4u, 4r twist

[0102] 5 Fixing elements

[0103] 6 Contact surface

[0104] 7 Shiftable sections

[0105] 8 Leave space

[0106] 9 Deformation pin

[0107] 10. Coating

[0108] 11. Contouring

[0109] 12 Local concave curvature

[0110] 12' Local convex curvature

[0111] 13 Improvement Department

Claims

1. A method for joining a first substrate (2u) to a second substrate (2o), wherein the first substrate (2u) has a primary section and the second substrate (2o) has a secondary section, wherein when joining the first substrate (2u) to the second substrate (2o) a first subsection in which the first substrate (2u) and the second substrate (2o) are connected, and a second subsection, in which the first substrate (2u) and the second substrate (2o) are still to be connected, A bonding wave (3) is formed between the two parts, which advances along the bonding direction. Preferably, a sub-region of the second substrate (2o) in the second sub-section is height-staggered relative to a sub-region of the second substrate (2o) in the first sub-section along a direction extending perpendicular to the main extension plane, and In order to achieve a relative orientation of the primary section and the secondary section relative to each other, in particular with respect to a direction extending essentially parallel to the joining direction, a first curvature of the first substrate (2u) and / or a second curvature of the second substrate (2o) are modified in an area adjacent to the joining wave (3) and / or in an area including the joining wave (3) by means of a deformation system.

2. The method according to claim 1, During joining, the difference between the first curvature and the second curvature is kept essentially constant at least in sections along the joining direction by means of the deformation system.

3. The method according to any one of the preceding claims, The deformation system comprises a plurality of deformation mechanisms, which are arranged along the joining direction.

4. The method according to any one of the preceding claims, During the joining process, the deformation system is varied, for example, by means of a control device.

5. The method according to any one of the preceding claims, The deformation system is thereby adjusted before joining.

6. The method according to any one of the preceding claims, In order to set the first curvature, a coating is arranged between the first substrate (2u) and a first substrate holder (1u), which supports the first substrate (2u) during the bonding process.

7. A device for joining a first substrate (2u) to a second substrate (2o), in particular by means of a method according to any one of the preceding claims, wherein the first substrate (2u) has a primary section and the second substrate (2o) has a secondary section, wherein the device is configured to, when joining the first substrate (2u) to the second substrate (2o), a first subsection in which the first substrate (2u) and the second substrate (2o) are connected, and a second subsection, in which the first substrate (2u) and the second substrate (2o) are still to be connected, A bonding wave (3) is formed between the two parts, which advances along the bonding direction. Preferably, a sub-region of the second substrate (2o) in the second sub-section is height-staggered relative to a sub-region of the second substrate (2o) in the first sub-section along a direction extending perpendicular to the main extension plane, The device comprises a deformation system for the relative orientation of the primary section and the secondary section relative to each other, in particular with respect to a direction extending essentially parallel to the joining direction, the deformation system being configured to be able to modify a first curvature of the first substrate (2u) and / or a second curvature of the second substrate (2o) in a region adjacent to the joining wave (3) and / or in a region including the joining wave (3).

8. The device according to claim 7, The first substrate (2u) is held in a first substrate holder (1u) when joined, wherein the first substrate holder (1u) has a fixing section and / or a deformation section, the fixing section has a fixing element (5) for fixing the first substrate (2u) and the deformation section has a deformation mechanism for setting the first curvature.

9. The device according to claim 8, In this case, fastening sections and deformation sections alternate at least partially along the joining direction.

10. The device according to any one of claims 7 to 9, The deformation system comprises a coating which is arranged between the first substrate (2u) and the second substrate holder (1u) and / or between the second substrate (2o) and the second substrate holder (1o) during the joining process.

11. The device according to any one of claims 7 to 10, The deformation system comprises a microstructure at the contact surface (6) of the first substrate holder (1u) and / or the second substrate holder (1o).

12. The device according to any one of the preceding claims, The deformation system comprises a contact surface (6) which is displaceable at least in sections.

13. The device according to any one of the preceding claims, The deformation system has a contact surface (6) which is contoured at least in sections, wherein the contoured contact surface (6) is concave, convex and / or stepped.

14. The device according to any one of claims 6 to 13, The first substrate holder (1u) and / or the second substrate holder (1o) as part of the deformation system has a raised portion in the edge region.

15. A device consisting of a first substrate (2u) and a second substrate (2o) manufactured by means of a method according to any one of claims 1 to 6, preferably manufactured by means of an apparatus according to any one of claims 7 to 14.

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