Apparatus and method for bonding substrate

Abstract

To provide an apparatus and a method for bonding substrates, which improve bonding accuracy at the edge of a substrate.SOLUTION: A method for bonding a first substrate (4o) to a second substrate (4u) at their facing contact surfaces (4k) includes steps of holding the first substrate (4o) on a holding surface (1s) of a first holding device (1o) and holding a second substrate (4u) on a holding surface (1s) of a second holding device (1u), and curving the contact surfaces before contact, and the change in curvature of the contact surface of the first substrate and / or the change in curvature of the contact surface of the second substrate is controlled during bonding.SELECTED DRAWING: Figure 4c

Description

[Technical field]

[0001] The invention relates to a method for bonding a first substrate to a second substrate according to claim 1 and to a corresponding device according to claim 9.

[0002] For several years, substrates have been bonded to one another in the semiconductor industry by a so-called bonding process. Before bonding, these substrates must be aligned to one another as accurately as possible, and deviations in the nanometer range that occur during this process are problematic. The substrates are aligned primarily via alignment marks. In addition to the alignment marks, the substrates also have other, particularly functional, elements that must also be aligned to one another during the bonding process. This alignment accuracy between the individual functional elements is required over the entire substrate surface. Thus, for example, it is not sufficient if the alignment accuracy is very good in the center of the substrate but decreases toward the edge.

[0003] In the prior art, for example in the literature EP2656378B1 or WO2014 / 191033A1, there are several methods and devices that can be used to try to influence the bonding process.

[0004] The greatest challenge in bonding is the bonding process itself, i.e., during the initial bonding phase until the contact surfaces of the substrates are completely in contact, where the alignment of the substrates with respect to each other may still vary significantly compared to their previous alignment. Once the substrate surfaces have been bonded to each other, they can indeed in theory be separated again, but this is costly, has low throughput, and is susceptible to errors.

[0005] An object of the present invention is to provide an apparatus and method for bonding two substrates, which can improve the bonding accuracy, particularly at the edges of the substrates.

[0006] This problem is solved by a device and a method with the features of claims 1 and 9. Preferred further configurations of the invention are defined in the dependent claims. All combinations of at least two features described in the description, claims and / or drawings are also within the scope of the invention. In the described numerical ranges, values ​​lying within the ranges are considered as disclosed as limit values ​​and can be claimed in any combination.

[0007] The idea behind the invention is to bend the substrates before they come into contact or before they are joined, and to vary this curvature of at least one of the substrates during joining, in particular during the course of the joining wave, preferably during the fusion joining, by controlled curvature. The curvature of the other (preferably upper) substrate is also preferably varied in a controlled manner.

[0008] The curvature may also be changed by automatic contact of the substrates, in particular by gravity acting on the substrates and / or other attractive forces between the substrates, and the control of the change in curvature of one (especially the lower) substrate as well as the change in curvature of the other (especially the upper) substrate is preferably dependent thereon (preferably by measurement and control) on the change in curvature.

[0009] The change in curvature means, in particular, a deviation from the initial state of the substrate (in particular the curvature present before contact). According to the invention, the bonding of the contact surfaces after contact is controlled in particular by controlled regulation of the fixation of the substrate. Corresponding fixing means are in particular provided as a device.

[0010] Another, particularly independent, aspect of the invention is the use of, in particular, individually switchable fastening elements, by means of which the bonding wave proceeding between the contact surfaces can be controlled in a closed or open loop manner.

[0011] Another idea according to the invention, in particular independently or in combination with the above, consists in the use of deformation elements as bending means and / or bending modification means, in particular formed as gas outlet openings, whereby mechanical contact with the substrate is avoided, and the control of the bending is made more precise by the combination of the above features.

[0012] The invention describes in particular a method and a device with which two substrates aligned to one another can be optimally bonded to one another, where the underlying idea is inter alia to control, close-loop or open-loop controlled bending, clamping and / or release of at least one of the substrates as appropriate, and thus to control, close-loop or open-loop controlled advancing bonding wave, so as to achieve a continuous optimal contact of the substrates along the contact surface, in particular proceeding from the inside to the outside. Optimal contact means in particular that the "runout" errors at each point of the contact surface between the substrates are minimal or in the best case absent.

[0013] According to one configuration, the fixing of the substrate is effected by means of a number of fixing elements, in particular divided into a number of sections.

[0014] According to another aspect, the bending of at least one of the substrates is achieved by positive pressure.

[0015] In the starting state, the substrate is usually largely flat, especially at the contact surface, except for structures (microchips, functional components) possibly protruding from the contact surface and substrate tolerances such as bending and / or thickness variations. However, in the starting state the substrate often has a curvature different from zero. For a 300 mm wafer, curvatures of less than 100 μm are typical. Mathematically, the curvature can be considered as a measure of the local deviation of a curve from its planar state. In particular, substrates whose thickness is small compared to their diameter are considered. It can therefore be called, in a good approximation, the curvature of a plane. In the case of a plane, the first-mentioned planar state is the tangential plane of the curve at the point where the curvature is observed. In general, objects, and in particular substrates, do not have a uniform curvature, so that the curvature is an explicit function of the position. Thus, an example is that a non-planar substrate has a concave curvature in the center, but a convex curvature in other places. According to the invention, a curvature or a curvature modification means, unless otherwise specified, a macroscopic curvature or a curvature modification, i.e. with respect to the entire substrate or the contact surface.

[0016] According to the invention, a convex curvature is preferred when viewed from the respective opposing substrate, and even more preferred if the curvatures of both substrates are mirror images of each other.

[0017] Another possibility to indicate the curvature at a given point consists in indicating the radius of curvature, which is the radius of a circle that is tangent to the surface and that contains the point of said surface.

[0018] Thus, the central independent idea in the main embodiment of the invention is that the radii of curvature of the two substrates to be joined together are primarily the same or at least slightly different from each other in the contact area of ​​the substrates, i.e. at the joining front or at the joining line of the joining wave. The difference between both radii of curvature at the joining front / joining line of the substrates is less than 10 m, preferably less than 1 m, more preferably less than 1 cm, more preferably less than 1 mm, more preferably less than 0.01 mm, most preferably less than 1 μm. In general, all embodiments according to the invention which minimize the difference between the radii of curvature R1, R2 are advantageous.

[0019] In other words: the present invention relates to a method and an apparatus that can bond two substrates together such that the two substrates have a minimal local alignment error, called "runout" error. Various "runout" errors are described in detail in WO2014 / 191033A1, to which reference may be made. The description of runout errors in WO2014 / 191033A1 is hereby expressly included in the disclosure content of this specification. A detailed description thereof is therefore omitted here.

[0020] In this case, more particularly, the idea underlying the invention is to control the curvature / curvature change of both substrates to be joined to one another, in particular by means of a fastening, in particular a controllable fastening over a large surface area, in such a way that the influencing factors for the resulting bond wave are selected in such a way that the two substrates do not slide locally relative to one another during bonding, i.e. remain precisely aligned. Furthermore, the invention describes an article consisting of two substrates to be joined to one another, which includes a "runout" error that is reduced according to the invention.

[0021] A characteristic process according to the invention during bonding, in particular permanent bonding, preferably fusion bonding, is that the two contact surfaces of the substrates come into contact as centrally and / or at a point as possible. In general, the contact of the two substrates does not have to take place centrally. The bond wave propagating from a non-central contact point reaches different points on the substrate edge at different times. A complete mathematical-physical description of the bond wave characteristics and the compensation of the resulting "runout" errors is therefore complex. The contact point is preferably not far from the center of the substrate, so that the effects that this may cause, especially at the substrate edge, can be neglected. The distance between the non-central possible contact point and the center of the substrate is in particular according to the invention less than 100 mm, preferably less than 10 mm, more preferably less than 1 mm, more preferably less than 0.1 mm, most preferably less than 0.01 mm. In the following description, contact usually means central contact. In the broad sense, central preferably means the geometric center point of the basic ideal object, with asymmetry compensated for if necessary. That is, in an industrially common wafer with a notch, the center is the circle center of a circle that encloses a virtual wafer without a notch. In an industrially common wafer with a flat portion (flat chamfered surface), the center is the circle center of a circle that encloses a virtual wafer without a flat portion. A similar idea applies to an arbitrarily shaped substrate. However, in a special embodiment, it may be beneficial to mean the center of gravity of the substrate by the center.

[0022] In order to ensure a precise and central point contact, according to an embodiment of the invention, a central hole and a pin that can translate in this hole are provided as the bending and / or curvature changing means, in particular a radially symmetrical fastening element is provided as the fastening means, in particular on the upper holding device (substrate holder). Instead of a pin, it is also conceivable to use a nozzle as the bending and / or curvature changing means, which is used to fluidly pressurize the substrate with a fluid, preferably with a gas, in particular directly (fluid pressurization means). With the alternative assumption that both substrates have a curvature that is pressed in the direction of the other substrate, in particular due to gravity and / or a preload, it is even possible to completely dispense with the use of elements of this type if a device is provided that can bring the substrates closer to each other by a translational movement. During the translational movement, the substrate automatically comes into contact with the corresponding second substrate at a sufficiently small distance.

[0023] The fastening element is according to an embodiment of the invention a provided exhaust hole, one or more circular exhaust lips or comparable exhaust elements on which the wafer can be fastened. The use of electrostatic fastening elements (fastening means) is also conceivable. A pin in the central hole or conduit, which can generate a positive pressure between the substrate holder and the substrate by the introduced gas, is used for the controllable bending of the fastened substrate (bending means and / or bending change means).

[0024] After the two substrates are in contact at the centers, the fastening means of the holding device are actuated in such a way that a controlled deformation / curvature of at least one of the substrates takes place. The upper substrate is pulled downwards in a controlled manner, on the one hand by gravity and, on the other hand, by the bonding forces acting between the substrates along the bonding wave. The upper substrate is thus bonded to the lower substrate in a radial direction from the center toward the side edges. This results in the inventive formation of a radially symmetrical bonding wave, which in particular runs from the center toward the side edges. During the bonding process, the substrates push the gas, in particular the air, present between the substrates forward of the bonding wave, thus resulting in a bonding interface free of gas inclusions. If the upper substrate is completely dropped, it actually sits on a sort of gas cushion. After a defined time point, all fastening elements of the substrate holder can be switched off, so that the upper substrate is left under the influence of gravity and / or the attractive forces between the substrates themselves. At this point, the bowing of the upper substrate is no longer open-loop or closed-loop controlled, but still proceeds in a controlled manner since the surrounding conditions are known or empirically determined. Based on this controlled bowing and the progression of the bonding wave, the bowing of the lower substrate is open-loop or closed-loop controlled. However, a preferred arrangement according to the present invention is to not let the upper substrate drop completely, but to fully control both substrates until the bonding wave has spread over at least 10% of the substrate area, preferably over 20%, more preferably over 30%, even more preferably over 50%, and most preferably over 75%.

[0025] From this point onwards, when all the fastening elements of the upper holding device are switched off, no special additional fastening is necessary; i.e. the upper substrate is free to move and may be distorted, except for the fastening at the bond start point. Due to the bond wave proceeding according to the invention, the stress state occurring at the bond wave front and the existing geometric edge conditions, each circle segment, which is infinitesimally small compared to the thickness in the half-shape direction, is distorted. However, since the substrate is a rigid object, the distortions are summed up as a function of the distance from the centre. This leads to a "runout" error, which is eliminated by the method according to the invention and the device according to the invention. It is also conceivable that the upper substrate is held fixed during the entire time section during which the bond wave proceeds, and that the proceeding of the bond wave can be advanced by successively switching off the fastening elements, in particular by starting from the fastening elements inside the substrate holder. The proceeding of the bond wave can also be advanced in particular by the approaching of both substrate holders to each other during the proceeding of the bond wave.

[0026] The present invention therefore particularly relates to methods and apparatus for reducing or even completely eliminating "runout" errors between two substrates being bonded, particularly by thermo-dynamic and / or mechanical compensation mechanisms, during bonding.

[0027] Furthermore, the invention relates to corresponding articles which are produced using the device according to the invention and the method according to the invention.

[0028] Holding device / substrate holder The substrate holder according to the invention has a fastening means, in particular a number of fastening elements. The fastening elements can be grouped in zones. By grouping the fastening elements in zones, geometrical, optical and preferably also functional objectives can be met. The functional objective means, for example, that all fastening elements in a zone can be switched simultaneously. It is also conceivable that all fastening elements in a zone can be switched individually. Thus, several fastening elements can be simultaneously actuated within a zone or actuated individually for clamping or releasing the substrate, but within the zone, very specific deformation characteristics of the substrate occur. The zones can in particular have the following geometry: ·One side, Circle segments, Tile-like areas, especially as triangles, squares, or hexagons In particular, there may be surfaces between the regions that are free of fastening elements. The distance between such regions is in particular less than 50 mm, preferably less than 25 mm, more preferably less than 20 mm, even more preferably less than 10 mm, most preferably less than 5 mm. If the regions are formed as circular segments, such a distance is the distance between the inner ring of the outer circular segment and the outer ring of the inner circular segment.

[0029] The number of fastening elements in a zone can be any number, in particular there is at least one fastening element in a zone, preferably at least two fastening elements, preferably 10 or more, more preferably 50 or more, more preferably 100 or more, more preferably 200 or more, most preferably 500 or more fastening elements.

[0030] According to a preferred embodiment of the invention, the first holding device and / or the second holding device have fastening means arranged around the holding surface of the first holding device and / or the second holding device for holding the substrate, in particular in the form of a ring, preferably in the form of a ring, in particular exclusively in the region of the side edge of the substrate.

[0031] The fastening means are formed as fastening elements, in particular divided into a plurality of zones, preferably arranged concentrically, distributed in particular uniformly over the holding surface, in particular individually controllable. Preferably, the fastening means are arranged in particular exclusively in the edge region of the holding surface. The edge region extends in particular up to half the radius of the holding surface, preferably up to one-quarter of the radius.

[0032] In the case where the fastening elements are arranged radially symmetrically in a zone, the number of fastening elements per given cross-section can also be taken into consideration: the number of fastening elements in a cross-section is less than 20, preferably less than 10, more preferably less than 5, even more preferably less than 3, and most preferably 1.

[0033] The clamping element can provide negative pressure for clamping and can also apply positive pressure for release of the substrate.

[0034] In a first embodiment according to the invention, the fastening element consists of a simple hole, in particular formed by drilling or spark erosion. In a special configuration, the fastening element is a ring-shaped, in particular annular, slit, in particular formed by milling. In another configuration, the fastening element can be provided with an exhaust lip. If the fastening element is provided as an exhaust element, it can generate pressures of less than 1 bar, preferably less than 0.1 mbar, more preferably less than 0.01 mbar, even more preferably less than 0.001 mbar, most preferably less than 0.0001 mbar.

[0035] In a second embodiment according to the invention, the fixing element consists of a conductive plate used as electrostatic fixation. The conductive plate can be connected monopole, but preferably bipole. In the case of a bipole circuit, the two plates are placed at opposite potentials. The substrate holder according to the invention therefore functions in its area as an electrostatic substrate holder with high-resolution electrostatic fixation properties, depending on the number of plates.

[0036] The more clamping elements per unit area, the better the control of the clamping properties of the substrate holder for the substrate.

[0037] Preferably, the first and / or second retaining surface comprises a ridge, in particular forming a first retaining plane of the first retaining surface and a second retaining plane of the second retaining surface.

[0038] According to two further embodiments, a holding device with a protuberance is described, in particular a protruding substrate holder. By such a substrate holder is meant in particular a substrate holder with a plurality of symmetrically arranged supports (in English: pillars). These supports are in particular formed as protuberances. The protuberances may have any shape. In particular the protuberances are provided with the following shapes: Pyramids, especially triangular or square pyramids Cylinders, especially those with a flat or rounded head · Cuboid ·cone -Sphere shell.

[0039] Whereas ball-shell, conical and cylindrical protrusions are laborious to manufacture, pyramidal or rectangular protrusions can be manufactured relatively easily by etching and / or milling and are therefore preferred according to the present invention.

[0040] The above-mentioned protrusion substrate sample holder may be closed in its peripheral region via edge elements, so that the spatial region between the protrusions may be interpreted as a recess, however the protrusions may form only one protuberance with respect to the protrusion plane on which all the protrusions lie.

[0041] In a third preferred embodiment of the invention, the substrate holder is configured as a protruding substrate holder with webs. In this case, the individual sections are interrupted by the webs. At least one duct terminates on the inside of each section, which evacuates the space between the protrusions. In particular, by using several individually controllably drivable passages, it is possible to evacuate the space with different intensities depending on the location.

[0042] In a fourth, more preferred embodiment, the substrate holder is configured as a full protruding substrate holder, ie without webs.

[0043] The width or diameter of the protuberances, especially the projections, is in particular less than 5 mm, preferably less than 1 mm, more preferably less than 500 μm, most preferably less than 200 μm.

[0044] The height of the protuberances, especially the projections, is in particular less than 2 mm, preferably less than 1 mm, more preferably less than 500 μm, most preferably less than 200 μm.

[0045] In particular, the ratio between the width or diameter of the ridge and the height of the ridge is greater than 0.01, preferably greater than 1, more preferably greater than 2, even more preferably greater than 10, and most preferably greater than 20.

[0046] All of the above-mentioned embodiments of the invention may be combined with one another in any way. Thus, it is also conceivable that the first section consists of electrostatically functioning fastening elements and the second section has a vacuum fastening.

[0047] The substrate holder according to the invention may in particular have a hole, hereinafter also referred to as a measurement hole, by means of which the surface of the fixed substrate can be observed from the rear side of the substrate holder. This allows a measurement of the surface of the fixed substrate in this area. The measurement hole can also be closed by a cover. In a particularly preferred embodiment, the measurement hole can be opened and closed fully automatically by means of the cover.

[0048] According to a preferred embodiment of the invention, the holding device comprises curvature measuring means for measuring the curvature.

[0049] The substrate holder according to the invention may alternatively or additionally comprise sensors capable of measuring physical and / or chemical properties between the clamped substrate and the substrate sample holder. These sensors are preferably: Temperature sensors and / or Pressure sensors and / or -Distance sensor.

[0050] Particularly suitable distance sensors can be used as curvature measuring means, in which case the curvature of the substrate, in particular between the support points, can be determined, interpolated and / or calculated via the distance between the substrate and the holding device.

[0051] According to the invention, preferably distance sensors are used, in particular distributed along the holding surface, in order to allow good closed-loop or open-loop control of the curvature and / or curvature modification.

[0052] In a particularly preferred configuration, the sensors are formed as distance sensors, in particular for measuring the distance of the substrate before and / or during the bonding process with respect to a plane, which plane is preferably the holding surface and / or a holding surface, in particular a plane formed by a ridge.

[0053] It is also conceivable that several sensors are located in different planes. The relation to one and / or several planes is not important, since the sensors preferably measure the distance changes in a direction, preferably transverse to the contact surface. In this case, only the relative distance changes, particularly in different locations, of the substrate need to be detected.

[0054] The measurement of the distance serves inter alia for process control: by knowing the exact state of curvature of the substrate or substrates, the drive control / adjustment of the clamping member according to the invention can be carried out particularly efficiently for an optimal, in particular gradual, release of the substrate.

[0055] It is also conceivable that a plurality of sensors of different types are integrated. In a particularly preferred embodiment, the sensors for distance measurement and pressure measurement are integrated in the substrate holder, in particular, symmetrically and uniformly distributed. This allows for discrete, but surface-covering distance and pressure measurements. Pressure measurements are particularly advantageous when the deformation element is a fluid, in particular a gas, or a gas mixture, which is introduced via a line.

[0056] If one or both holding devices are formed without curvature measuring means and / or without sensors, the adjustment and / or control of the curvature and / or curvature change can be performed on the basis of empirically determined parameters.

[0057] The first and second substrate holders according to the invention preferably comprise at least one, in particular centrally arranged, deformation means (bending means and / or bending modification means) for bending / changing the bending of the substrate.

[0058] According to a first embodiment according to the invention, the bending element is a pin (English: pin). This pin has at least one, preferably exactly one, degree of freedom of translation along a normal to the holding surface or plane. For calibration in the x- and / or y-direction, it is also conceivable that the pin has a degree of freedom along the holding surface. Preferably, the pin is fixable in the x- and / or y-direction. The pin can exert a force of 0.01 N to 1000 N, preferably of 0.1 N to 500 N, more preferably of 0.25 to 100 N, most preferably of 0.5 to 10 N.

[0059] In a second embodiment according to the invention, the deformation element for the curvature and / or curvature modification is a fluid outlet opening (fluid pressurizing means) with which a fluid, in particular a gas or gas mixture, can be supplied between the substrate and the holding surface. In a very preferred embodiment according to the invention, the fluid outlet opening is integrated into a specific partial element, in particular movable in the x- and / or y-direction, so that the positioning in the x-direction and / or the positioning in the y-direction of the fluid outlet opening can be performed. This allows the position of the fluid outlet opening to be precisely defined, which can also affect the optimal joining result according to the invention. The fluid outlet opening is in the simplest case an opening forming the end of a pipe line. In a very particularly preferred embodiment, the fluid outlet opening is a nozzle. This nozzle can preferably be controlled electronically, so that the fluid pressure and / or the outflow speed of the outflowing fluid can be controlled in an open-loop and / or closed-loop manner at each time. The use of several nozzles is also conceivable in order to vary the pressure formation at several points between the substrate sample holder and the substrate. All statements about one nozzle apply equally to several nozzles. Via the fluid outlet opening, in particular the nozzle, a pressure of 1 mbar or more, preferably 10 mbar or more, more preferably 100 mbar or more, more preferably 200 mbar or more, most preferably 500 mbar or more can be created between the substrate and the substrate holder. All substrate holders according to the invention can have loading pins. The loading pins are used to load the substrate onto the substrate holder according to the invention. The loading pins are in particular guided through holes in the holding device. In this case, the holes are preferably formed closely to the loading pins.

[0060] In a first process step, the loading pin is moved out. In a second process step, the substrate is placed on the loading pin, in particular in a fully automatic manner. In a third process step, the loading pin is moved back in and the substrate is brought into contact with the holding surface. In a fourth process step, the substrate is fixed by the fixing element. The loading pin is also used for unloading the joined substrate stack. In this case, the order of the process steps is accordingly reversed. The loading pin may form a vacuum body, in particular if it is not sealed against the hole in which the loading pin moves. In this case, the static maintenance of a negative pressure via the vacuum fixing element and / or the static maintenance of a positive pressure via the gas outflow opening is not possible. Correspondingly, a continuous evacuation via the vacuum fixing element and / or the creation of a continuous positive pressure via the gas outflow opening, which is preferably characterized by a static, in particular laminar, flow, is disclosed. However, the use of a seal is also conceivable, by which a static pressure can be created without creating a flow.

[0061] The substrate holder can in principle be made of any material. One or more of the following materials are particularly suitable: Metals, especially Pure metals, especially ·aluminum Alloys, especially Steel, especially ·Low alloy steel, Ceramics, especially Glass-ceramics, especially Zerodur, Nitride ceramics, especially Silicon nitride, Carbide ceramics, especially Silicon carbide, Polymers, especially High temperature polymers, especially Teflon, ·Polyetheretherketone (PEEK).

[0062] In a highly preferred embodiment, the protruding substrate sample holder according to the invention is manufactured in a manner known from the patent document EP2655006B1. In this case, the preferred material is silicon carbide or silicon nitride. In this case, the preferred protruding structure is a square pyramid.

[0063] According to an embodiment of the present invention, the holding device is preferably formed to be heatable and / or coolable, in which case the temperature control mechanism allows the substrate to be heat-treated at -50°C to 500°C, preferably -25°C to 300°C, more preferably 0°C to 200°C, and most preferably 10°C to 100°C.

[0064] In another embodiment of the invention, the substrate holder is designed such that the substrate is intentionally deformed, in particular laterally compressed or stretched, by the heating and / or cooling means before it is contacted, and is deformed by the amount required to compensate as well as possible, ideally completely, the "runout" errors that have occurred during subsequent contact. In this embodiment, no particular importance is attached to the thermal expansion coefficient of the lower / first substrate or the lower / first holding device, since the fixing of the lower / first substrate only takes place after the corresponding deformation. In a particularly preferred embodiment of the protruding substrate holder according to the invention, the substrate can be contacted with the heating gas via the spatial region between the protrusions. In order to maintain the fixability of the fixing element, the pressure of the heating gas must be lower than the ambient gas, which presses the substrate against the substrate holder in the region of the area.

[0065] joining machine The device according to the invention comprises two holding devices and / or substrate holders according to the invention. Preferably, at least the upper substrate holder has a measuring hole. The measuring hole is in particular designed to be closable and / or gas-tight.

[0066] Embodiments according to the invention preferably operate in a defined, especially controllable, atmosphere, especially at atmospheric pressure.

[0067] All the above-mentioned embodiments of the invention can be carried out in particular variants in low vacuum, more preferably in high vacuum, even more preferably in ultra-high vacuum, in particular at pressures below 100 mbar, preferably below 0.1 mbar, more preferably below 0.001 mbar, even more preferably below 10e-5 mbar, most preferably below 10e-8 mbar. The higher the vacuum or the lower the ambient pressure, the more difficult it is to fix the substrate by the exhaust hole.

[0068] process In a first process step according to the invention of the first process according to the invention, the first substrate is loaded onto a first substrate holder and the second substrate onto a second substrate holder and fixed, particularly at the peripheral sections.

[0069] In the second process step according to the invention of the first process according to the invention, both substrates are aligned with each other. The alignment of the substrates is not described in detail here. For that, reference is made to the documents US6214692B1, WO2015082020A1, WO2014202106A1. The substrates are in particular aligned with each other before the bonding process, so as to ensure the overlap of corresponding structures on their surfaces (in particular with a precise alignment with an accuracy of less than 2 μm, preferably less than 250 nm, more preferably less than 150 nm, even more preferably less than 100 nm, most preferably less than 50 nm).

[0070] In the third additional process step according to the invention of the first process according to the invention, the two substrates are brought together by a relative movement of the two substrate holders towards each other, which results in a well-defined gap between the substrate surfaces. It is also conceivable to adjust such a gap already before or during the alignment process. This gap is in particular smaller than 1000 μm, preferably smaller than 500 μm, more preferably smaller than 250 μm and most preferably smaller than 100 μm.

[0071] It is particularly preferred according to the invention that the deviation of the radii of curvature of both substrates from each other, especially at the joining front, is less than 15%, preferably less than 10%, more preferably less than 5%, even more preferably less than 2%, and most preferably the radii of curvature of both substrates are the same.

[0072] In a fourth process step according to the invention of the first process according to the invention, a curvature of the first and / or second substrate is performed. At the same time, the curvature of the first and / or second substrate is measured and monitored by a sensor. By means of an adjustment loop, a particularly desired curvature of the lower and / or upper substrate can be automatically adjusted. A target value is set. The adjustment loop controls the fixing elements and / or deformation elements until the desired curvature profile is adjusted. In this case, it is mentioned that gravity acts in one direction and therefore can act differently on the deformation of the substrate. While the upper fixed substrate is further deformed by gravity in the direction of the desired contact point, this gravity acts against the curvature of the lower substrate. However, the influence of gravity is so small that it does not have to be taken into account. By using automatically open-loop or closed-loop controlled curvature or curvature modification means, fixing elements and sensors according to the invention, a desired curvature profile can be adjusted for each of both substrates, particularly as part of an adjustment loop. When both substrates are approached sufficiently close to each other, contact of both substrates is performed. The contact can be effected by an ever-increasing curvature and / or by the relative approach of the two substrate holders, i.e. in the bonding method according to the invention the substrates are not laid flat on top of each other but are first brought into contact with one another at the center M (bonding initiation point). This is effected by one of the curved substrates being pressed lightly against the second substrate or being correspondingly deformed in the direction of the opposite substrate. After the deformed and bent substrate (in the direction of the opposite substrate) is released, the advance of the bonding wave results in an automatic, in particular at least partial, preferably mostly, continuous and uniform bonding along the bonding front with minimal forces and thus with minimal distortions, mainly in the horizontal direction.

[0073] In the fifth process step of the invention of the first process according to the invention, the bonding wave is advanced, monitored and controlled. If the bonding start point is arranged in the center of the contact surface of the substrate, a uniform, particularly concentric, course of the bonding wave can be achieved.

[0074] It is particularly advantageous if the deformation, preferably the curvature, of the first and / or second substrate is effected laterally and / or convexly and / or concavely, more preferably with mirror symmetry, in other words the deformation is effected according to the invention in particular by stretching and / or compressing and / or curving the first and / or second substrate.

[0075] The substrates preferably have approximately the same diameters D1, D2, the deviation of these diameters from one another being in particular less than 5 mm, preferably less than 3 mm, more preferably less than 1 mm.

[0076] In particular, according to another independent aspect of the invention, the deformation, preferably the curvature, is effected by a deformation means or a curvature means and / or a curvature changing means and / or by temperature control of the first and / or second holding device.

[0077] By fixing the first substrate and / or the second substrate exclusively in the peripheral or all-around area of ​​the first substrate holder and / or the second substrate holder or of the first and / or second substrate, the deformation / bending / curving change according to the invention can be achieved relatively easily.

[0078] The control of the above-mentioned steps and / or movements and / or courses, in particular of the deformation means or the bending means and / or the bending change means and / or the fastening means, the mutual approach of the substrates, the temperature control, the pressure control and the gas composition control are preferably effected via a central control unit, in particular via a computer with control software. For the open-loop and / or closed-loop control, the above-mentioned sensors are used.

[0079] In order to give the substrate as much flexibility and freedom of extension as possible within the fastening, it is advantageous for the substrate to be fastened only in the region of the side edges at circle segments that are located as far outwards as possible.

[0080] The first and / or second substrate is advantageously radially symmetric. The substrate can have any diameter, but the substrate diameter is in particular 1 inch, 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 8 inches, 12 inches, 18 inches or more than 18 inches. The thickness of the first and / or second substrate is between 1 μm and 2000 μm, advantageously between 10 μm and 1500 μm, and even more advantageously between 100 μm and 1000 μm.

[0081] In a particular embodiment, the substrate may have a shape which is different from a rectangular shape or at least a circular shape.Preferably, a wafer is used as the substrate.

[0082] Particularly preferably, all the variable parameters are selected in such a way that the bonding wave propagates at the most optimal speed possible with respect to the existing initial and ambient conditions. Particularly in the existing atmosphere, in particular at normal pressure, a speed of the bonding wave that is as slow as possible is advantageous. The average speed of the bonding wave is in particular slower than 200 cm / s, more preferably slower than 100 cm / s, more preferably slower than 50 cm / s, very preferably slower than 10 cm / s, most preferably slower than 1 cm / s. In particular, the speed of the bonding wave is faster than 0.1 cm / s. In particular, the speed of the bonding wave is constant along the bonding front. In a vacuum atmosphere, the speed of the bonding wave is automatically faster, because the substrates to be bonded along the bonding line do not have to overcome the resistance of the gas.

[0083] Another, particularly independent, aspect of the invention is to apply a preload to at least one of the substrates before the contact, which preload extends radially outward, particularly concentrically with respect to the center M of the contact surface of the substrate, and then only influences the start of the contact, and after the contact of one section of the substrate, particularly the center M, the substrate is released and joined to the opposing substrate in an automatically controlled manner based on the preload, so that the contact is as coordinated as possible and at the same time almost automatic. The preload is obtained by deformation, particularly bending, of the first substrate by deformation means, particularly bending means and / or bending change means. In this case, the deformation means act on the side opposite to the joining side, particularly based on its shape, and the deformation is accordingly controllable by the use of various (particularly interchangeable) deformation means. The control is also performed by the pressure or force with which the deformation element is applied to the substrate. In this case, the effective holding area of ​​the substrate holder with the substrate is advantageously reduced, so that the substrate is only partially supported by the holding device. In this way, due to the small contact surface, the adhesion between the substrate and the substrate holder is small. According to the invention, the clamping is performed in particular in the area of ​​the entire circumference of the substrate, so that an effective clamping is achieved and at the same time an effective holding area as small as possible between the holding contour of the substrate holder and the substrate. The release force required for the detachment of the substrate is thus minimal, so that a clean and reliable detachment of the substrate is possible. The detachment is particularly controllable, in particular by reducing the negative pressure at the holding surface. Controllable means that after the substrate has come into contact with the second substrate, it still remains fixed on the sample holder and only by a desired (controlled) reduction of the negative pressure at the holding surface is the substrate (wafer) released from the sample holder (holding device) in particular from the inside out. The embodiment according to the invention leads in particular to the fact that the detachment can be performed with very little force. In particular, various methods of release are disclosed. sudden complete release of the substrate while the deformation means is stopped, sudden complete release of the substrate when the deformation means is naturally placed in its starting state and therefore immediately ceases to act on the substrate, a sudden and complete release of the substrate when the deformation means gradually but continuously ceases to act on the substrate; Stepwise, in particular section-by-section, preferably from the inside to the outside, release of the substrate by fixed, step-by-step switching off while the deformation means are acting on the substrate; A combination of the above methods.

[0084] An embodiment according to the invention discloses a bonding process where, in the best mode, both substrates are curved, however in general at least one substrate may be undeformed. In combination with the release mechanism described above, the following table is presented: [Table 1]

[0085] Features disclosed for the apparatus are equally applicable as if they were disclosed for the method, and vice versa.

[0086] Other advantages, features and details of the present invention will become apparent from the following description of the preferred embodiments and the drawings. [Brief description of the drawings]

[0087] [Figure 1] Figure 1a is a schematic partial view, not to scale, of a first embodiment of a holding device according to the present invention, Figure 1b is a schematic partial view, not to scale, of a second embodiment of a holding device according to the present invention, Figure 1c is a schematic partial view, not to scale, of a third embodiment of a holding device according to the present invention, Figure 1d is a schematic partial view, not to scale, of a fourth embodiment of a holding device according to the present invention, Figure 1e is a schematic partial view, not to scale, of a first embodiment of a bending (changing) means by a holding device according to the present invention, and Figure 1f is a schematic partial view, not to scale, of a second embodiment of a bending (changing) means by a holding device according to the present invention. [Figure 2a] FIG. 13 is a schematic, not to scale, plan view of a fifth embodiment of a holding device according to the invention; [Figure 2b]FIG. 13 is a schematic, not to scale, plan view of a sixth embodiment of a holding device according to the invention; [Figure 2c] FIG. 13 is a schematic, not to scale, plan view of a seventh embodiment of a holding device according to the invention; [Figure 2d] FIG. 13 is a schematic, not to scale, plan view of an eighth embodiment of a retaining device according to the invention; [Figure 2e] FIG. 13 is a schematic, not to scale, plan view of a ninth embodiment of a retaining device according to the invention; [Diagram 3] 3a-3e are schematic, not to scale, side and top views of embodiments of ridges according to the present invention. [Figure 4a] FIG. 2 shows a schematic, not to scale, cross-sectional view of an embodiment of a seaming machine according to the invention in a first method step of the method according to the invention together with pressure and distance graphs. [Figure 4b] 4b-4c are schematic, not-to-scale, cross-sectional views of the embodiment of FIG. 4a at different method steps; [Figure 4c] 4b-4c are schematic, not-to-scale, cross-sectional views of the embodiment of FIG. 4a at different method steps; [Figure 4d] 4b-4c are schematic, not-to-scale, cross-sectional views of the embodiment of FIG. 4a at different method steps; [Figure 4e] 4b-4c are schematic, not-to-scale, cross-sectional views of the embodiment of FIG. 4a at different method steps;

[0088] In the drawings, identical components and components having the same function are provided with the same reference numbers.

[0089] 1a shows a schematic, not to scale, partial cross-section of a first configuration of a holding device 1 (also alternatively called substrate holder) according to the invention, where only the edge region R with the fastening elements 2 (fastening means) is shown.

[0090] The holding device 1 consists of several zones Zi, which are preferably present in the edge region R. Each zone Zi has several fastening elements 2. In Fig. 1a, for example, two zones Z1 and Z2 are shown. In the first zone Z1, four fastening elements 2 are shown in cross section, and in the second zone Z2, two fastening elements 2 are shown. In particular, the zones Zi can be limited to the edge region R of the substrate holder 1 or can be distributed over the entire substrate holder 1.

[0091] The fastening element 2 is used for fastening a substrate carrying surface 4a of a first, in particular an upper, substrate 4o or a second, in particular a lower, substrate 4u.

[0092] Preferably, a number of sensors 3, 3', in particular distance sensors, are located on the holding surface 1s. The sensors are used to measure physical and / or chemical properties between the fixed substrate 4 and the holding surface 1s. The sensors 3, 3' are in particular distance sensors which measure the distance between the holding surface 1s and the substrate holding surface 4a.

[0093] The substrate holder 1 is preferably configured in such a way that in its centre C (see Fig. 1e and Fig. 1f) there is a bending element 5, 5' (bending means) by means of which the substrates 4o, 4u fixed on the substrate holder 1 can be bent. Particularly preferably, the bending element 5 is a fluid outlet opening, via which a gas, in particular a compressed gas, can be discharged between the substrate holder 1 and the substrate 4. By means of the positive pressure the substrate 4 is bent and at the same time fixed by the fixing element 2 or released in a controlled manner.

[0094] In the alternative configuration according to the invention shown in FIG. 1f, the bending element 5′ is a pin which extends through the holding device 1 and is configured to be movable perpendicularly to the holding device (bending means or bending change means).

[0095] The comments regarding figures 1e and 1f apply analogously to the arrangement according to figures 1a to 1d.

[0096] In Fig. 1b, a second configuration of the substrate holder 1' according to the invention is shown. The substrate holder 1' consists of several zones Zi, which are preferably present in the edge region R'. Each zone Zi can generally have several fastening elements 2'. The fastening elements 2' are electrodes of electrostatic fastening. In Fig. 1b, for example, two zones Z1 and Z2 are shown. In the first zone Z1, two fastening elements 2' are shown in cross section, and in the second zone Z2, three fastening elements 2' are shown in cross section. In particular, the zones Zi can be limited to the outer edge of the substrate holder 1' or can be distributed over the entire substrate holder 1'.

[0097] Preferably, a number of sensors 3, 3', in particular distance sensors, are located on the holding surface 1s'. The sensors 3, 3' are used to measure physical and / or chemical properties between the fixed substrate 4 and the holding surface 1s'. The sensors 3, 3' are in particular distance sensors which measure the distance between the holding surface 1s' and the substrate holding surface 4a.

[0098] FIG. 1c discloses a third configuration of a substrate holder 1″ according to the invention. The substrate holder 1″ consists of several zones Zi, which are preferably present exclusively in the edge region R″. Each zone Zi has in particular several fixing elements 2″.

[0099] The fastening element 2'' is a web 8 or edge element 10 adjacent to the substrate-holding surface 4a and a spatial area 9 between the web 8 and the bottom surface pierced by the conduit 6. In the conduit 6, the pressure for sucking and thus fastening the substrates 4o, 4u is adjusted.

[0100] Located in the spatial region 9 are in particular a number of projections 7, on which the substrates 4o, 4u rest. The projections 7 serve in particular to avoid excessive contamination. The projections 7 are shown larger than average in Fig. 1c for the sake of clarity. In reality, the projections 7 are significantly smaller compared to the thickness of the substrate holder 1''.

[0101] In Fig. 1c, for example, two zones Z1 and Z2 are shown. In the first zone Z1, three fastening elements 2' are shown in cross section, and in the second zone Z2, likewise three fastening elements 2'' are shown in cross section. In particular, the zones Zi may be limited to the outer edge of the substrate holder 1'' or may be distributed over the entire substrate holder 1''.

[0102] Preferably, a number of sensors 3, 3', in particular distance sensors, are located on the protrusions 7, in particular on the protrusion surfaces 7o of the protrusions 7 which contact the substrate-carrying surface 4a in the uncurved state. The sensors are used to measure physical and / or chemical properties between the fixed substrate 4 and the carrying surface 1s'' defined by the protrusion surface 7o and the surrounding edge elements 10. The sensors 3, 3' are in particular distance sensors which measure the distance between the protrusion surface 7o and the substrate surface 4o.

[0103] In Fig. 1d a fourth configuration of the substrate holder 1''' according to the invention is shown. The substrate holder 1''' in particular consists of several zones Zi which are preferably present in the edge region R'''. Each zone Zi has several fixing elements 2'''.

[0104] The fixing element 2''' is a spatial area 9 between two adjacent pipes 6 in which pressure can build up. The spatial area 9 is only defined around the periphery of the holding device 1''' by a surrounding edge element 10, on which the substrates 4o, 4u rest in annular form and which together with the protruding surface 7o form the holding surface 1s''.

[0105] Located in the spatial region 9 are in particular a number of protrusions 7, which can hold the substrates 4o, 4u on their protrusion surfaces 7o. The protrusions 7 serve in particular to avoid excessive contamination. The protrusions 7 are shown larger than average in Fig. 1d for the sake of clarity. In reality, the protrusions are significantly smaller compared to the thickness of the substrate holder 1''''.

[0106] In Fig. 1d, for example, two zones Z1 and Z2 are shown. In the first zone Z1, one fastening element 2''' is shown in cross section, and in the second zone Z2, one fastening element 2''' is also shown in cross section. In particular, the zones Zi may be limited to the outer edge of the substrate holder 1''' or may be distributed over the entire substrate holder 1'''.

[0107] Preferably, a number of sensors 3, 3', in particular distance sensors, are located on the bottom surface in the spatial region 9 between the protrusions 7. The sensors 3, 3' are used to measure physical and / or chemical properties between the fixed substrate 4 and the bottom surface. The sensors 3, 3' are in particular distance sensors which measure the distance between the bottom surface and the substrate-holding surface 4a. Based on the known height of the protrusions 7, the distance between the substrate-holding surface 1a and the protrusion surface 7o can thereby be calculated.

[0108] The holding device 1 shown in FIG. IV In the holding device 1, the fixing elements 2 are arranged in four concentric zones Z1 to Z4. IV A curved element 5, 5' (see FIG. 1e or FIG. 1f) is located at the center C of each of the sections. The corresponding fixing elements 2 of the sections are respectively arranged along a straight line L extending in the radial direction.

[0109] The holding device 1 shown in FIG. V In the holding device 1, the fixing elements 2 are arranged in four zones Z1 to Z4. V At the center C of each of the sections, a curved element 5, 5' (see Fig. 1e or Fig. 1f) is located. The corresponding fastening elements 2 of the sections are respectively arranged along a line L' that does not pass through the curved element 5, and in particular does not pass through the center C. The line L' does not necessarily have to be a straight line. The corresponding fastening elements 2 that face each other are arranged in mirror symmetry with respect to the center C.

[0110] FIG. 2c shows a holding device 1 having a number of projections 7 surrounded by edge elements 10 as in the configuration according to FIG. 1c. VIBetween the protrusions 7, the fixing element 2 is inserted during evacuation. IV In this configuration according to the invention, spatial regions 9 are located which function as a vacuum pump. The exhaust takes place via the conduits 6. In this configuration according to the invention, there are no webs 8 separating the spatial regions 9 from one another, so that the fluid introduced via the curved elements 5 (see FIG. 1e) is sucked out again directly via the conduits 6. Thus, this configuration according to the invention is advantageous in that the substrate holder 1 is not only VI 4 is an example of a substrate holder in which a static laminar flow is formed between the substrate and the substrates 4o, 4u.

[0111] In the inventive configuration shown in Fig. 2d, several zones Z are provided, each with three fastening elements 2. The zones Z are configured as hexagons and at least approximately cover the holding surface. The centre C and the periphery are left uncovered.

[0112] In the inventive configuration shown in Fig. 2e, the fastening elements 2 are arranged along a spiral. In this case, the entire holding surface 1s is only one zone Z. It is conceivable to control the fastening elements individually or in groups. At the end and center C of the spiral, curved elements 5, 5' are arranged.

[0113] All configurations according to Figures 2a to 2e are holding devices in which the clamping is performed as negative pressure clamping or vacuum clamping. Corresponding substrate holders with electrostatic clamping can also be realized. The sensors 3, 3' are not shown for clarity but can be configured corresponding to the configurations according to Figures 1a to 1d.

[0114] In figures 3a to 3e, examples of shapes of the protuberances 7, 7', 7'', 7'''', 7'''' are shown. The shape of figure 3a consists of a cylindrical base body with a rounded head. The shape of figure 3b consists of a cylindrical base body with a flat head. The shape of figure 3c consists of a hemispherical base body. The shape of figure 3d consists of a triangular pyramid. The shape of figure 3e consists of a square pyramid.

[0115] 4a shows a bonding machine 13 according to the invention, which brings into contact and bonds the oppositely arranged contact surfaces 4k of a first / upper substrate 4o and a second / lower substrate 4u. The bonding machine 13 consists of a lower substrate holder 1u and an upper substrate holder 1o. The substrate holders 1u, 1o in particular comprise the above-mentioned holding devices 1,1',1'',1''',1 for holding the first / upper substrate 4o and the second / lower substrate 4u. IV ,1 V ,1 VI in which case the lower substrate holder 1u may be configured or equipped differently than the upper substrate holder 1o.

[0116] The upper substrate holder 1o preferably has measuring holes 12, via which the substrate 4o can be measured from the rear side of the substrate holder 1o. Alternatively, sensors can be arranged in the measuring holes. The measuring holes 12 are arranged in particular between the bending-changing means and the fastening element. Alternatively or additionally, the lower substrate holder 1u can have corresponding measuring holes 12. The measuring holes run through the holding device 1 and in particular perpendicularly to the holding surface 1s. The measuring holes 12 are arranged in particular equidistantly with respect to the center of the holding surface 1s. The measuring holes 12 are preferably arranged at an interval of 180° or 120° from one another.

[0117] The substrate holder 1u, 1o has a holding surface 1s with a number of fastening elements 2 and sensors 3, 3'. The fastening elements 2 are evacuated via a line 6 and fasten the substrates 4u, 4o. Above and below the substrate holder 1u, 1o are plotted graphs, which respectively show the distance d between the sensor 3 configured as a distance sensor and the substrates 4u, 4o along the x direction (substrate diameter) for each x position. The distance sensors 3 are distributed from the curvature changing means 5 to the fastening means. The distance sensors therefore extend over a partial surface of the holding surface 1s.

[0118] In the region of the fixing means 2, a sensor 3' configured as a pressure sensor is arranged, by means of which a pressure p1 is measured between the substrates 4u, 4o and the substrate holders 1u, 1o along the x-position of the sensor 3'.

[0119] In the distance graph, the target curvatures 15u, 15o, which are set by the software, and the actual curvatures 14u, 14o, which are measured by the distance sensor, are displayed. The upper substrate 4o has an actual curvature 14o, which is present due to gravity, whereas the lower substrate 4u is placed flat and therefore does not have an actual curvature 14u in the present invention (in fact it has only a very small curvature). However, it is also conceivable that the actual curvature 14o caused by gravity is negligibly small. The two curvatures 15u, 15o to be achieved are mirror images in the exemplary embodiment. Any curvatures 15u, 15o can be set. The pressure distributions 16u and 16o show a pressure drop in the working area of ​​the fastening element 2, which indicates that the fastening of the substrates 4u, 4o is taking place.

[0120] The process step of aligning both substrates 4u, 4o with respect to each other is not shown.

[0121] In figure 4b the bonder 13 is shown in another process step: the two substrates 4u, 4o are brought closer together by relative movement of the two substrate holders 1u, 1o, otherwise unchanged from the situation in figure 4a.

[0122] In Fig. 4c the bonding machine 13 is shown in another process step. By using a bending element 5, which in the illustrated example is a gas outlet opening through which gas flows at pressure p2, both substrates 4u, 4o are brought to the target curvature, the pressure being preferably regulated by the distance sensor 3. For the closed / open loop control, the pressure of the fastening element 2 can also be used, whereby the fastening element can also take on the role of the bending means 5, 5' or the curvature changing means 5, 5', so that in the context of the present invention the fastening element 2 is also considered as a bending means.

[0123] For this in the illustrated example, the pressure of one of the fastening elements 2 is increased from pressure p1 to pressure p0 in order to achieve the desired curvature before contacting the substrates 4o, 4u. For simplicity, in the illustrated example, only three pressure values ​​p0, p1, p2 are shown. The pressure values ​​are in particular continuously and / or always closed-loop / open-loop controllable.

[0124] In Fig. 4d the bonding machine 13 is shown in another process step. The two substrates 4u, 4o form a bonding wave which, due to the approach of the substrates 4u, 4o, extends radially outwards. In this case the curvature of the substrates 4u, 4o is continuously changed (curvature changing means). In this case the curvature change of the lower substrate 4u and the upper substrate 4o is continuously monitored by distance sensors and, if necessary, corrected by the bending elements 5 and / or the fastening elements 2 in such a way that the respectively desired or set target curvature is achieved (curvature changing means). The important parameters are the radius of curvature R1 of the upper substrate 4o and the radius of curvature R2 of the lower substrate 4u at the point of the bonding wave.

[0125] The pressure of the four innermost circumferential rows of fastening elements 2 is simultaneously increased to p0 in the upper and lower holding devices 1o and 1u, so that the substrates 4u, 4o lose their adhesion to the holding surface 1s, in particular from the inside to the outside, and the pressure p2 from the curved elements 5 can spread further.

[0126] The control minimizes runout errors by taking into account the curvature and curvature changes of the substrates 4o, 4u.

[0127] In figure 4e the bonding machine 13 is shown in another process step: both substrates 4u, 4o are bonded together in a controlled manner by increasing the pressure of the outermost row of fastening elements 2 of the upper holding device 1o to p0. [Explanation of symbols]

[0128] 1,1',1'',1''' Holding device / substrate holder 1 IV ,1 V ,1 VI Holding device / substrate holder 1o First holding device / upper substrate holder 1u Secondary Retention Device / Lower Board Holder 1s,1s',1s'',1s''' Holding surface 2,2',2'',2''' fixed elements 2o'' Fixed element surface 3,3' Sensor 4o First / Top Board 4u Second / Bottom Board 4a Board holding surface 5,5' curved element 6 conduit 7,7',7'',7''',7'''' Ridge / Protrusion 7o Projection surface 8. Web 9 Spatial domain 10 Edge element 11 Projection plane 12 Measuring holes 13 Joining machine 14u,14o Actual curve 15u,15o target curvature 16u,16o Pressure Progression L,L' line x position d Distance p Pressure R1,R2 radius of curvature

Claims

1. A method for bonding a first substrate (4o) to a second substrate (4u) at mutually facing contact surfaces (4k) of said substrates (4o, 4u), comprising the following steps, in particular the following sequence: The first substrate (4o) is held by a first holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ ) and the second substrate (4u) is held by a first holding surface (1s, 1s', 1s'', 1s''') of a second holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ ) on a second holding surface (1s, 1s', 1s'', 1s'''); A method comprising the step of curving the contact surfaces (4k) before contacting the contact surfaces (4k), 1. A method for bonding a first substrate (4o) to a second substrate (4u), characterized in that the curvature modification of the contact surface (4k) of the first substrate (4o) and / or the curvature modification of the contact surface (4k) of the second substrate (4u) is controlled during bonding.

2. 2. The method according to claim 1, wherein the curvature and / or curvature modification is adjusted and / or controlled mirror-symmetrically and / or concentrically with respect to the contact surfaces (4k) before the contact between the contact surfaces (4k).

3. 3. Method according to claim 1 or 2, characterized in that the curving and / or the curvature change is / are performed by means of a curving means (5'), in particular a pin, which is in particular mechanical.

4. 4. The method according to claim 1, wherein at least one of the curvature and / or curvature change is adjusted and / or controlled by fluid pressure, in particular by a fluid that applies a load directly to the substrate.

5. 5. The method according to claim 1, further comprising fastening the first substrate (4o) and / or the second substrate (4u) by fastening means arranged, in particular in the shape of a ring, preferably in the shape of a ring, around the entire circumference of the holding surface (1s, 1s', 1s'', 1s''', in particular exclusively in the region of the side edges (4os, 4us) of the substrates (4o, 4u).

6. 6. The method according to claim 5, wherein the fastening means comprises fastening elements (2), in particular individually controllable fastening elements (2), which are distributed in particular evenly over the holding surface (1s, 1s', 1s'', 1s'''), preferably arranged concentrically, and divided into a plurality of zones.

7. 7. The method according to claim 1, further comprising forming the first retaining surface (1s, 1s', 1s'', 1s''') and / or the second retaining surface (1s, 1s', 1s'', 1s''') from a ridge (7, 7', 7'', 7'''', 7''''), which in particular forms a first retaining plane of the first retaining surface (1s, 1s', 1s'', 1s''') and a second retaining plane of the second retaining surface (1s, 1s', 1s'', 1s''').

8. 8. The method according to claim 1, wherein the curvature and / or the curvature change is detected by a curvature measuring means, in particular a sensor (3), preferably a distance sensor, arranged in particular along the first and / or second holding surface (1s, 1s', 1s'', 1s''').

9. 1. An apparatus for bonding a first substrate (4o) to a second substrate (4u) at opposing contact surfaces (4k) of said substrates (4o, 4u), comprising: A first holding device (1, 1', 1'', 1''', 1') holds a first substrate (4o) on a first holding surface (1s, 1s', 1s'', 1s'''). ＩＶ , 1 Ｖ , 1 ＶＩ ) and a second holding device (1, 1', 1'', 1''', 1') that holds a second substrate (4u) on a second holding surface (1s, 1s', 1s'', 1s'''). ＩＶ , 1 Ｖ , 1 ＶＩ )and, and a bending means for bending the contact surfaces (4k) before they come into contact with each other, 1. An apparatus for bonding a first substrate (4o) to a second substrate (4u), characterized in that the curvature-changing means for changing the curvature of the first substrate (4o) and / or the curvature-changing means for changing the curvature of the second substrate (4u) are controllable during bonding.

10. The first holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ ) and / or said second holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ 10. The device according to claim 9, wherein the bending means comprises in particular mechanical bending means and / or fluid pressure means for adjusting and / or controlling the bending and / or bending modification.

11. The first holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ ) and / or said second holding device (1, 1', 1'', 1''', 1 ＩＶ , 1 Ｖ , 1 ＶＩ 11. The device according to claim 9 or 10, characterized in that the holding surface (1s, 1s', 1s'', 1s''') has fastening means arranged in particular in the shape of a ring, preferably in the shape of a ring, around the entire circumference of the holding surface (1s, 1s', 1s'', 1s''', in particular exclusively in the area of ​​the side edges (4os, 4us) of the base plate (4o, 4u).

12. 12. The device according to claim 11, wherein the fastening means comprises fastening elements (2), in particular individually controllable fastening elements (2), which are distributed in particular evenly over the holding surfaces (1s, 1s', 1s'', 1s'''), preferably arranged concentrically, and divided into a plurality of sections.

13. 13. The device according to claim 9, wherein the first holding surface (1s, 1s', 1s'', 1s''') and / or the second holding surface (1s, 1s', 1s'', 1s''') are / is formed by a ridge (7, 7', 7'', 7'''', 7''''), which in particular forms a first holding plane of the first holding surface (1s, 1s', 1s'', 1s''') and a second holding plane of the second holding surface (1s, 1s', 1s'', 1s''').

14. 14. The device according to claim 9, wherein the curvature and / or curvature change is detectable by curvature measuring means, in particular a sensor, preferably a distance sensor, arranged in particular along the first and / or second holding surface (1s, 1s', 1s'', 1s''').

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