Apparatus and method for joining substrates

Abstract

To provide a device and a method for bonding two substrates to improve bonding accuracy.SOLUTION: A method using a bonding machine (13) is a method of bonding a first substrate (4o) to a second substrate (4u) at the contact surfaces (4k) of the substrates (4o, 4u) that face each other, the first substrate (4o) is held by a first holding device (1o), the second substrate (4u) is held by a second holding device (1u), a plate (17u) is disposed between the second substrate (4u) and the second holding device (1u), and the second substrate (4u) together with the plate (17u) is deformed relative to the second holding device (1u) before and / or during bonding.SELECTED DRAWING: Figure 2d

Description

Technical Field

[0001] The present invention relates to a method for bonding a first substrate according to claim 1 to a second substrate, as well as to a corresponding apparatus according to claim 8. Further, the present invention relates to a plate according to claim 15.

[0002] For several years, in the semiconductor industry, substrates have been bonded to each other by means of a so-called bonding process. Before connection, the substrates must be aligned with each other as precisely as possible, in which case the displacement in the nanometer range occurring between them has an impact. In this case, the alignment of the substrates is mainly carried out via alignment marks. In addition to the alignment marks, there are further, particularly functional elements on the substrates which must also be aligned with each other during the bonding process, and which are hereinafter also referred to as structures. Such alignment accuracy between the individual functional elements is required over the entire substrate surface. Thus, for example, if the alignment accuracy is very good at the center of the substrate but decreases towards the edge, it cannot be said to be sufficient.

[0003] Chucks exist in various configurations. Particularly important with regard to chucks is a flat holding surface or support surface for holding / fixing the substrate so that structures on the substrate can be accurately aligned and brought into contact over the entire substrate surface.

[0004] In the prior art, there are already devices that can at least partially reduce local strain. The technique is the removal of local strain by using active control elements according to WO 2012 / 083978.

[0005] Furthermore, prior art also provides a first solution for correcting "runout" errors. U.S. Patent Application Publication No. 20120077329 describes a method for achieving desired alignment accuracy between functional units of two substrates during and after bonding by not fixing the position of the lower substrate. This allows the lower substrate to be freely bonded to the upper substrate during the bonding process, without being constrained by boundary conditions.

[0006] The alignment process is crucial when joining substrates. One of the biggest technical challenges when joining two substrates is the accuracy of the functional units between the individual substrates. While substrates can be aligned with extreme precision using alignment equipment, they can still be warped during the bonding process. Due to the distortion that occurs during the bonding process, functional units are not always perfectly aligned with each other at all locations. The alignment accuracy at a given point on the substrate can be a result of distortion, scaling errors, lens defects (magnification or reduction errors), etc. In the semiconductor industry, all topics related to this type of problem are encompassed under the concept of "overlay." Overlay refers to the overlapping accuracy of a structure consisting of various manufacturing steps.

[0007] In particular, overlay errors that occur during the bonding process due to distortion in at least one substrate are called "runout" errors. Distortion in at least one substrate causes functional units of the first substrate to be distorted with respect to functional units of the second substrate. Such distortion is not only a problem when bonding two structured substrates, but can also be a major problem when bonding one structured substrate to one nearly unstructured substrate. This can be especially problematic if further process steps requiring extremely precise alignment of the structured substrate are to be performed after bonding.

[0008] The resulting "runout" error is often radially symmetrical around the point of contact and therefore increases from the point of contact toward the periphery. In many cases, the "runout" error is reinforced to increase linearly. However, under special conditions, the "runout" error can also increase non-linearly.

[0009] The object of the present invention is to provide an apparatus and method for joining two substrates to improve bonding accuracy.

[0010] This problem is solved by the features of multiple parallel, independent claims. Another preferred configuration of the present invention is described in the dependent claims. All combinations of at least two features described in the specification, claims, and / or drawings are also within the scope of the present invention. Within the numerical ranges described, values ​​within the above range are also deemed to be disclosed as limit values ​​and can be claimed in any combination.

[0011] The fundamental idea behind this invention is to place a plate between at least one of the substrates and a corresponding retaining device, and to bend the substrate together with this plate relative to the retaining device before and / or during bonding. Therefore, the preferably flat retaining surface of the retaining device that holds the plate and the substrate is not deformed. In particular, the retaining device works to deform / bend the plate, and the bending of the plate causes the substrate, which is fixed in place on the plate, to also bend.

[0012] The present invention particularly describes a method and apparatus for improving the bonding of two substrates. In particular, this improvement means minimizing the “runout” error. In this case, the fundamental idea of ​​the present invention is to place a plate between the substrate and the retaining device, which can itself fix the substrate in place and which can be fixed in place by a retaining device on the one hand. The plate, preferably a ceramic plate, is fixed in place by a retaining device in particular which can locally drive and control the fixing. The fixing part (in particular consisting of fixing means / fixing elements) is grouped into several sections in particular. Preferably, in the center of the retaining device is a device for bending the plate, particularly a partially fixed plate. The bending device is called a bending element. The bending element is particularly a nozzle that can release a fluid, preferably a gas, between the plate and the retaining device to generate an overpressure that bends the plate, and therefore the substrate fixed on the plate. The bending of the plate occurs by fixing the plate, preferably at its periphery, through a vacuum by the retaining device. The plate holds the substrate during the bonding process, preferably fixing its position, thereby forming a system consisting of the plate and the substrate. This system and / or the plate has higher bending resistance than the substrate alone. The increased bending resistance of this system is advantageous in minimizing "runout" errors. Bending resistance is characterized by the bending resistance moment.

[0013] The core of the present invention lies in placing a bendable plate between at least one of the two substrates and the holding device. The plate is bent, particularly at or from the center of the substrate or plate, by a bending mechanism, particularly by compressed air. The bending of the two substrates is performed with a predetermined gap, and this gap is preferably reduced as the bonding wave progresses to allow full contact of the substrates. The bending element of the bending mechanism for bending is located, particularly inside the positioning portion, preferably at the center.

[0014] In this case, the plate (placed beneath the substrate) can be completely separated from the retaining device. To achieve this, the retaining device's positioning, particularly vacuum retention, is stopped, while the bending mechanism, especially compressed air, remains operational. Therefore, as long as compressed air is used, the lower plate floats on the air cushion in this state, allowing for full contact with the substrate. Since the substrate is held in place by the plate, its thickness increases, and its bending rigidity improves. In this case, its flexibility is also reduced, resulting in a significant improvement in the bonding outcome.

[0015] Once the plate is completely released from the retaining device, the position of the substrate by or to the plate is maintained, particularly by a vacuum, preferably via a particularly expandable or extendable retaining element connection. This allows the position of the substrate to be maintained independently of the control and positioning of the plate in the retaining device.

[0016] Therefore, the main advantage of the present invention is that it can almost completely eliminate various errors, particularly "runout" errors and residual errors.

[0017] In addition to "runout" errors, particularly those caused by distortion, there are also translational errors, rotational errors, and residual errors. Translational errors are caused by undesirable translational movements of structures on the substrate plane, while rotational errors are caused by undesirable rotations. Residual errors refer to all other errors that cannot be classified as "runout" errors, and / or translational errors, and / or rotational errors. The sum of all errors will be referred to as overlay below.

[0018] Translational and / or rotational errors are primarily due to the fact that the two substrates are not precisely aligned with each other before the bonding process begins. Therefore, substrate alignment is preferably performed by an appropriate alignment device. Examples of alignment devices are described in the publications cited, U.S. Patent No. 6,214692, International Publication No. 2014202106, and International Publication No. 2015082020. Alignment is preferably performed based on alignment marks and / or on functional units present on the substrate. Alignment accuracy is particularly good than 500 nm, preferably good than 300 nm, even more preferably good than 150 nm, even more preferably good than 100 nm, and most preferably good than 20 nm.

[0019] The "runout" error between the two structures is particularly less than 500 nm, preferably less than 300 nm, more preferably less than 150 nm, even more preferably less than 100 nm, and most preferably less than 20 nm.

[0020] The residual error is preferably less than 100 nm, preferably less than 50 nm, even more preferably less than 30 nm, even more preferably less than 20 nm, and most preferably less than 10 nm.

[0021] The apparatus and method according to the present invention can reduce the overlay to less than 500 nm, preferably less than 300 nm, more preferably less than 150 nm, even more preferably less than 100 nm, and most preferably less than 50 nm.

[0022] The apparatus according to the present invention can perform the optimal bonding process through a closed control loop.

[0023] Various plates of different thicknesses allow for adjustment of flexibility, particularly bending stiffness, as desired. In particular, multiple plates of this type can be provided that are easily, quickly, effectively, and inexpensively replaceable. Therefore, when using various substrates, they can be adapted to each substrate at each stage.

[0024] Although not preferred, according to the present invention, it is also conceivable to stack multiple plates on top of each other.

[0025] In other words, the fundamental idea of ​​the present invention is to deform at least one of the two substrates, preferably both substrates, for the purpose of aligning the contact surfaces, particularly before and / or during bonding, preferably during fusion bonding, and to place a plate between at least one of the two substrates and the holding device, with the plate itself fixed in position to the holding device, and the substrate being fixed in position on this plate.

[0026] Deformation specifically refers to a state in which the substrate deviates from its initial state, particularly its initial geometry.

[0027] Accordingly, the present invention relates to a method and apparatus for reducing or completely eliminating a “runout” error between two substrates to be joined during bonding, particularly by a thermodynamic and / or mechanical compensation mechanism. Furthermore, the present invention relates to corresponding articles manufactured using the apparatus and method according to the present invention.

[0028] According to the present invention, after contact of the contact surface of the substrate, the bonding is initiated, in particular, by the release of the upper plate and / or the lower plate. However, by using at least one plate according to the present invention, unlike the prior art, the substrate is stiffened by the plate, so that the bending resistance of the system composed of the substrate and the plate increases, and thus extremely precisely controllable release is also possible. Therefore, according to the present invention, in the following process of this specification, a method for bonding based on a controlled bonding process that can omit the spontaneous dropping of the upper substrate and / or the upper plate provided with the substrate fixed thereon is also described.

[0029] holding device In the following process of this specification, first, an embodiment of the present invention regarding a holding device including a plate and a substrate will be described. According to the present invention, later, one device having two holding devices of such a form is also disclosed. In this case, the plate according to the present invention may be used only in one of the two holding devices or in both holding devices. When only one plate is used, this plate may be located in the upper, but preferably the lower holding device. A preferred embodiment according to the present invention is to use two plates according to the present invention between one substrate and the corresponding holding device, respectively.

[0030] substrate The first substrate and / or the second substrate is preferably radially symmetric. The substrate can have any diameter, but the substrate diameter is particularly 1 inch, 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 8 inches, 12 inches, 18 inches, or larger than 18 inches. The thickness of the first substrate and / or the second substrate is 1 μm to 2000 μm, preferably 10 μm to 1500 μm, more preferably 100 μm to 1000 μm. In a special embodiment, the substrate may have a shape different from a square shape or at least a circular shape. The substrate is understood to be particularly a wafer in the following process.

[0031] Preferably, the substrates have approximately the same diameters D1 and D2, and the difference between these diameters is particularly less than 5 mm, preferably less than 3 mm, and even more preferably less than 1 mm.

[0032] plate Another, particularly independent, aspect lies in the configuration of the plate and its use between the substrate and the retaining device. Specifically, the plate is positioned on the side opposite to the substrate, on top of the bending means or curvature changing means of the retaining device. Thus, the substrate is not deformed directly, but the deformation of the substrate is indirectly achieved by the deformation of the plate by the curvature changing means.

[0033] The plate is preferably fixed in position by a holding device or can be fixed in position.

[0034] The plates are made, in particular, mostly or entirely from ceramics, preferably from industrial ceramics. The plates may be coated.

[0035] The plate has the same diameter as the substrate that is fixed / positionable on this plate.

[0036] According to a preferred embodiment of the present invention, the plate has a larger radius than the substrate that is fixed on the plate. Having a larger diameter than the substrate allows the plate to be preferably fixed to the holding device in a region that extends beyond the substrate.

[0037] In particular, the radius of the plate corresponds to at least 1.01 times, preferably more than 1.1 times, more preferably more than 1.2 times, even more preferably more than 1.3 times, and most preferably more than 1.4 times, the radius of the substrate to be fixed. Particularly preferred embodiments of the plate according to the present invention have a diameter 10% to 20% larger than the diameter of the substrate to be fixed. By using a plate with a radius considerably larger than the radius of the substrate to be fixed, according to the present invention, a certain curvature in the substrate can be adjusted, thereby the substrate forming a perfectly hollow spherical shell on the plate. By using position fixing of the plate in the holding device, particularly acting exclusively in the peripheral region, the plate may be curved at the periphery so significantly that the curvature of the substrate deviates from such an ideal constant curvature.

[0038] Thin substrates, due to their minimal thickness, have extremely low bending resistance. This low bending resistance results in extremely high flexibility, making it difficult to control the bonding process as intended. This has the disadvantage that errors, particularly voids, can negatively affect the bonding result in the center. By additionally supporting the substrate with a plate, the plate supports the substrate, which is fixed on the plate, during the bonding process, so the low bending resistance of the substrate is not a problem. A particularly independent aspect of the present invention is the formation of a system consisting of a plate and a substrate, wherein this system has higher bending resistance than individual substrates (without a plate).

[0039] The plate may have a stepped portion, particularly at its edge. Since the stepped portion is removed in the direction of the retaining device, a void is created between the plate and the retaining device at the periphery. This void allows for optimal deformation of the plate in the edge region, and consequently supports the deformation.

[0040] In a special embodiment of the present invention, the plate according to the present invention may be supported on a plurality of piezoelectric elements and may be fixed in position. By such means, the plate can be deformed locally.

[0041] Plate materials The plate is characterized, in particular, by material parameters such as purity, inherent stiffness, flatness, and deformability. The plate is positioned between a retaining device and a substrate fixed / fixable on the retaining device. The plate is formed to be sufficiently thick on the one hand so as not to be deformed by undesirable external influences and to provide sufficient support to the substrate located on it, and on the other hand so as to bend when subjected to a force acting as intended (compressed air, vacuum, mechanical, pneumatic, or electrical actuator). The plate can have a convex and / or concave shape.

[0042] In particular, the plate has heat resistance exceeding 500°C, preferably exceeding 750°C, and even more preferably exceeding 1000°C.

[0043] The plate may be coated. The plate and / or coating, in particular, consist of at least part, preferably mostly, one or more of the following materials: • Metals, especially ○Cu, AG, Au, Al, Fe, Ni, Co, Pt, W, Cr, Pb, Ti, Ta, Zn, Sn, • Semiconductors, especially ○Ge, Si, α-tin, fullerene, B, Se, Te, • Compound semiconductors, especially ○GaAs, GaN, InP, InxGal-xN, InSb, InAs, GaSb, AlN, InN, GaP, BeTe, ZnO, CuInGaSe2, ZnS, ZnSe, ZnTe, CdS, CdSe, CdT e, Hg(lx)Cd(x)Te, BeSe, HgS, AlxGal-xAs, GaS, GaSe, GaTe, InS, InSe, InTe, CuInSe2, CuInS2, CuInGaS2, SiC, SiGe, • In particular, any one of the above materials • Alloys, especially steel, preferably, ○Special steel ○Tool steel ○ Hot-worked steel ○High speed steel • Plastics, especially ○ Thermoplastic plastics, preferably, □Polyetheretherketone (PEEK) □Polytetrafluoroethylene (PTFE) □Polyimide □Polyamideimide ○ Thermosetting plastics ○ Elastomer • Ceramics, especially ○Aluminum oxide Al2O3, ○ Zirconia ZrO2, ○Silicon carbide, especially, □ Reaction-bonded silicon-filtered silicon carbide (SiSiC), □Silicon carbide (SiC) □Silicon nitride Si3N4 □Oxynitride bonded silicon carbide NSiC □ Sintered silicon carbide (SSiC) • Glass

[0044] In a preferred embodiment, the plate is a ceramic plate. Preferably, the plate is made from a special oxide ceramic, in particular aluminum oxide (Al2O3).

[0045] In a particular embodiment, the plate consists of a high-strength and elastically deformable diaphragm. In particular, the elastic diaphragm may be made of a film material.

[0046] Plate radius of curvature The radii of curvature of the first and / or second plates at the time of joining, particularly at the start of joining, are particularly greater than 0.01 m, preferably greater than 0.1 m, more preferably greater than 1 m, more preferably greater than 10 m, more preferably greater than 100 m, and most preferably greater than 1000 m.

[0047] In a preferred embodiment, the radius of curvature of the first / lower plate is the same as the radius of curvature of the second / upper plate. This results in a geometrically symmetrical starting position for joining.

[0048] In a preferred embodiment, the radius of curvature of the plate is adjustable. The controlled curvature of the plate is advantageous according to the present invention, as it ensures that the difference between the radii of curvature of both substrates, particularly at the bonding front, is less than 5%, and more preferably equal to each other.

[0049] plate thickness The thickness of the deformable plate is particularly 0.1 to 10 mm, preferably 0.25 to 8 mm, even more preferably 0.5 to 6 mm, and most preferably 1 to 5 mm.

[0050] Plate modulus The modulus of elasticity (Young's modulus) is a material property value that represents the relationship between expansion and stress during deformation of a solid in linear elastic behavior. The modulus of elasticity of the plate is 0.01 GPa to 1100 GPa, preferably 0.1 GPa to 800 GPa, more preferably 1 GPa to 600 GPa, even more preferably 10 GPa to 500 GPa, and most preferably 100 GPa to 450 GPa.

[0051] The plate, in particular, has a higher modulus of elasticity than the substrate.

[0052] The plate has sufficient inherent rigidity to ensure problem-free handling of the substrate and to provide optimal support characteristics.

[0053] Plate roughness Plate roughness is described as average roughness, two-dimensional roughness, or average roughness depth. The calculated values ​​for average roughness, two-dimensional roughness, and average roughness depth generally differ for the same measurement distance or measurement area, but are within the same order of magnitude. Therefore, the following numerical ranges for roughness are understood as values ​​relating to average roughness, or two-dimensional roughness, or average roughness depth. In this case, the roughness is less than 100 μm, preferably less than 10 μm, more preferably less than 1 μm, still more preferably less than 100 nm, and most preferably less than 10 nm.

[0054] Holding device / curved element Another idea according to the present invention, either independent or in combination with the above, lies in the use of deformation elements as bending means and / or bending modification means.

[0055] The plate and / or substrate is curved. Curvature is understood to be the reciprocal of the radius of curvature of a circle (2D) or sphere (3D) at the point of contact where the curvature should be defined. Therefore, the curvature of the plate and / or substrate may be particularly dependent on its position. However, preferably, the curvature is constant at all points on a single circle centered at the center of the substrate.

[0056] Instead of curvature, bend is preferably described. Throughout this specification, bend is understood to be the distance from the center of the raised surface of an object to the fixed surface of the object. Specifically, therefore, bend means the distance at the center between the surface of the plate facing the direction of the retaining device and the surface of the retaining device. The bend is particularly adjusted to less than 1 mm, preferably less than 500 μm, more preferably less than 100 μm, still more preferably less than 50 μm, and most preferably less than 10 μm.

[0057] In its initial state, the substrate is flat, particularly at the contact surface, except for substrate tolerances such as structures (microchips, functional components) that may protrude from the contact surface, and bending and / or thickness variations. The substrate has at most a very slight bend in its initial state. For a 300 mm wafer, a bend of less than 50 μm is preferable.

[0058] According to a first embodiment of the present invention, the curved element is a gas outlet opening. The gas outlet opening may be a single nozzle (or more nozzles). The plate can be curved, in particular by a gas flow that creates overpressure. The plate is fixed in place by a retaining device via vacuum, particularly around its periphery, so that the plate curves / bends.

[0059] According to a second embodiment of the present invention, the curved element is a piezo device, particularly a piezo column.

[0060] According to a third embodiment of the present invention, the curved element is a rigid object capable of translational movement, in particular a pin. The pin is adjustable by a hydraulic element and / or a pneumatic element and / or a piezoelectric element. It is also conceivable that a nozzle is located within the pin, thereby obtaining a combined curved element.

[0061] According to a fourth embodiment of the present invention, the bending element is one or more electrodes. A charged material is placed on the substrate (which is undesirable from a technical standpoint) or an influenceable charge is provided on the substrate so that the substrate can be bent by the electrodes.

[0062] According to a fifth embodiment of the present invention, the bending element is one or more electric coils. The substrate has a magnetic material or an inductable magnetic field is formed on the substrate so that the substrate can be bent by the coils.

[0063] The curved element is incorporated into the retaining device, preferably in the center. The curved element is particularly open-loop controllable and / or closed-loop controllable.

[0064] In particular, it is possible to provide multiple curved elements that can deform the plate or substrate at various points, but this is not preferable.

[0065] A characteristic process of the present invention during bonding, particularly during permanent bonding, preferably fusion bonding, is that the two substrates make point contact as close to the center as possible. Selectively, contact between the two substrates does not have to occur in the center. The distance between the center and any possible non-central contact points of the substrates is particularly less than 100 mm, preferably less than 10 mm, more preferably less than 1 mm, even more preferably less than 0.1 mm, and most preferably less than 0.01 mm.

[0066] Preferably, contact means contact at the center. Center preferably means the geometric center point of the underlying virtual object, with asymmetry compensated as necessary. That is, in an industrially common wafer with a notch, the center is the center of the circle surrounding the virtual wafer without the notch. In an industrially common wafer with a flat surface, the center is the center of the circle surrounding the virtual wafer without the flat portion. A similar idea applies to arbitrarily shaped substrates. If explicitity is required / explicitly explained, or if the above definition is to be replaced, alternatively, center means the centroid of the substrate.

[0067] According to the present invention, only one of the plates and / or only one of the substrates, preferably the lower plate and / or the lower substrate, may be deformed. In this case, the other substrate, preferably the upper substrate, automatically comes into contact with the deformed substrate by the upper plate, particularly based on gravity. Preferably, the upper substrate has a curvature toward the lower substrate, particularly caused by gravity.

[0068] Plate and / or retaining device - curvature measuring means According to a preferred configuration of the present invention, the plate and / or holding device has curvature measuring means for measuring curvature.

[0069] The plate and / or retaining device may optionally or additionally have sensors capable of measuring the physical and / or chemical properties between the fixed substrate and the plate, and / or between the plate and the retaining device. These sensors are preferably, • Temperature sensor and / or • Pressure sensor and / or It is a distance sensor.

[0070] It is also conceivable that multiple sensors of different types be incorporated. In a particularly preferred embodiment, sensors for distance measurement and pressure measurement are incorporated in particular, uniformly and symmetrically distributed on the plate and / or retaining device. This allows for discrete, but comprehensive, distance and pressure measurements across the surface. Pressure measurement is particularly advantageous when the curved element is a fluid, especially a gas, or a gas mixture delivered through the passage.

[0071] The data from the curvature measurement means and sensors are used, in particular, for closed-loop / open-loop control.

[0072] Plate and / or holder - heating element In further embodiments of the present invention, the plate and / or retaining device are formed such that the substrate and / or plate can be temperature-controlled, particularly in a predetermined section. Temperature control allows for additional deformation of the substrate and / or plate as intended. If the coefficients of thermal expansion of the substrate and the plate, or the plate and the retaining device, are different, the substrate will particularly follow the thermal expansion of the plate, or the plate will particularly follow the thermal expansion of the retaining device. Preferably, the substrate and / or plate are pre-temperature-controlled or brought to a desired temperature by heating and / or cooling means before being fixed in position to the plate or the retaining device.

[0073] The holding device and / or plate can be temperature-controlled within a temperature range of -100°C to 500°C, preferably -50°C to 450°C, more preferably -25°C to 400°C, and most preferably 0°C to 350°C.

[0074] Plate and / or retaining device - position fixing part and fixing element According to the present invention, a plate fixing portion is provided, thereby fixing or making it possible to fix the substrate in position on the plate. Furthermore, a retaining device fixing portion is provided, thereby fixing or making it possible to fix the substrate in position on the retaining device, particularly via the plate. Since both fixing portions are essentially the same and of the same type, they will be described only once. The structure, grouping, and division of the above fixing portions may also be the same with respect to the plate and retaining device according to the present invention. However, it is also conceivable that they may be configured differently.

[0075] The positioning of the substrate to the plate or the positioning of the plate to the holding device is preferably performed in the outer region of the substrate, and more preferably in the region of the plate that extends beyond the substrate.

[0076] In order to give the substrate or plate as much flexibility and degree of stretching freedom as possible within the fixed portion toward the center, it is advantageous for the substrate or plate to be fixed only by circular segments located as far away as possible from the outer edge region.

[0077] A single position-fixing section preferably consists of multiple fixing elements. The fixing elements may be grouped by area. Grouping the fixing elements by area satisfies morphological, optical, and preferably functional challenges. Functional challenges include, for example, the ability to switch all fixing elements in one area simultaneously. It is also conceivable that all fixing elements in one area can be switched individually. Therefore, multiple fixing elements can be driven and controlled within an area, or individually, to simultaneously fix or release the position of the substrate or plate, but this results in highly unique deformation characteristics of the substrate or plate within that area.

[0078] The area may have the following geometry in particular: ·One side • Circle segment, • Areas that are tiled, especially in the shape of a triangle, square, or hexagon.

[0079] In particular, there may be surfaces between the regions that do not have fixed elements. The spacing between such regions is particularly less than 50 mm, preferably less than 25 mm, more preferably less than 20 mm, even more preferably less than 10 mm, and most preferably less than 5 mm. If the regions are formed as circular segments, such spacing is the distance between the inner ring of the outer circular segment and the outer ring of the inner circular segment.

[0080] The number of fixed elements in a single area is arbitrary. In particular, a single area contains at least one fixed element, preferably at least two fixed elements, preferably 10 or more, more preferably 50 or more, even more preferably 100 or more, even more preferably 200 or more, and most preferably 500 or more fixed elements.

[0081] According to a preferred embodiment of the present invention, the first retaining device and / or the second retaining device have fixing means arranged particularly in a ring shape, preferably annularly, on the periphery of the retaining surface of the first retaining device and / or the second retaining device for holding a plate, and particularly exclusively in the region of the side edge of the plate / substrate.

[0082] The fixing means is formed as a particularly individually controllable fixing element divided into multiple areas, preferably concentrically arranged and uniformly distributed across the retaining surface. Preferably, the fixing means is located exclusively in the edge region of the retaining surface. The edge region extends, in particular, up to half the radius of the retaining surface, preferably up to one-quarter of the radius.

[0083] When the fixed elements are arranged radially symmetrically within a single area, the number of fixed elements per given cross-section can also be considered. In this case, the number of fixed elements per cross-section is less than 20, preferably less than 10, even more preferably less than 5, even more preferably less than 3, and most preferably 1.

[0084] A fixing element capable of supplying negative pressure for fixation can also be subjected to positive pressure for releasing the substrate.

[0085] In a first embodiment of the present invention, the fixing element consists of a simple hole formed in particular by drilling or spark erosion. In a special embodiment, the fixing element is a slit formed in a ring shape, particularly annular, particularly by milling. In another configuration, the fixing element may be provided with a vacuum lip. When the fixing element is provided as a vacuum element, the fixing element can generate a pressure 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, and most preferably less than 0.0001 mbar.

[0086] In a second embodiment of the present invention, the device comprises a fixed element and a conductive plate used for electrostatic fixation. The conductive plate can be connected unipolarly, preferably bipolarly. In the case of a bipolar circuit, the two plates are placed at opposite potentials. Therefore, the retaining device according to the present invention functions particularly within a region as an electrostatic retaining device having high-resolution electrostatic fixation characteristics dependent on the number of plates.

[0087] The more fixed elements there are per unit area, the better the control over the fixing characteristics of the substrate holder.

[0088] Preferably, the first retaining surface and / or the second retaining surface consist of, in particular, a raised portion that forms a first retaining plane of the first retaining surface and a second retaining plane of the second retaining surface.

[0089] According to two other embodiments, a retaining device and / or plate having protrusions, in particular a projection retaining device or projection plate, is described. Such a retaining device or plate means a retaining device or plate having a plurality of symmetrically arranged pillars, which are formed in particular as projections. The projections may have any shape. In particular, the projections are provided in the following shapes: • Pyramids, especially triangular or square pyramids, • Cylinders, especially cylinders with flat or rounded tops, • Rectangular prism, ·cone, • Spherical shell.

[0090] While spherical shell protrusions, conical protrusions, and cylindrical protrusions are time-consuming 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.

[0091] The above-described projection holding device or projection plate may be closed off at its peripheral region via edge elements, so the spatial region between projections may be interpreted as a recess. However, each projection may form only one raised portion with respect to the projection plane on which all projections lie.

[0092] In a third preferred embodiment of the present invention, the retaining device is configured as a projection retaining device with a web, and / or the plate is configured as a projection plate with a web. In this case, the individual sections are interrupted by the web. Inside each section, at least one conduit terminates for exhausting the space between the projections. In particular, by using multiple individually driveable passages, it is possible to exhaust the space with different intensity depending on the location.

[0093] In a further preferred fourth embodiment, the retaining device and / or plate is configured as a complete projection retaining device or projection plate, i.e., without a web.

[0094] The width or diameter of the raised portion, especially the protrusion, is less than 5 mm, preferably less than 1 mm, more preferably less than 500 μm, and most preferably less than 200 μm.

[0095] The height of the raised portion, especially the protrusion, is less than 2 mm, preferably less than 1 mm, more preferably less than 500 μm, and most preferably less than 200 μm.

[0096] In particular, the ratio between the width or diameter of the raised portion and the height of the raised portion is greater than 0.01, preferably greater than 1, even more preferably greater than 2, even more preferably greater than 10, and most preferably greater than 20.

[0097] All embodiments of the present invention described above may be combined in any way. For example, the first region may consist of an electrostatically functioning fixing element, and the second region may have vacuum fixing.

[0098] The holding device and / or plate according to the present invention may have a hole, which will be referred to hereafter as a measuring hole, through which the fixed substrate surface can be observed from the back of the holding device and plate. This makes it possible to measure the fixed substrate surface in this area. The measuring hole can also be closed by a cover. In a particularly preferred embodiment, the measuring hole can be opened and closed fully automatically by the cover.

[0099] The holding device according to the present invention may selectively or additionally have sensors capable of measuring the physical and / or chemical properties between the fixed substrate and the holding device. These sensors are preferably: • Temperature sensor and / or • Pressure sensor and / or It is a distance sensor.

[0100] A particularly suitable distance sensor can be used as a curvature measuring means. In this case, the curvature of the substrate or plate, particularly between support points, is determined, interpolated, and / or calculated based on the distance between the substrate and the retaining device, or the distance between the plate and the retaining device.

[0101] Preferably, according to the present invention, distance sensors are used, particularly distributed along the retaining surface, to enable good closed-loop or open-loop control of deformation, especially curvature and / or curvature changes.

[0102] In a particularly preferred embodiment, a plurality of sensors are formed as distance sensors to measure, among other things, the distance of a substrate or plate with respect to a plane before and / or during the bonding process. This plane is preferably a retaining surface, and / or a retaining surface of a plane formed by a raised portion in particular.

[0103] It is possible that multiple sensors are located on different planes. Preferably, the sensors measure changes in distance lateral to the contact surface, so the relationship to one and / or more planes is not important. In this case, it is sufficient to detect only the relative distance changes of the substrate or plate, especially those that differ in location.

[0104] Distance measurement is particularly useful for process control. Knowing the precise curvature of the substrate or plate allows for particularly efficient drive control / adjustment of the fixing element according to the present invention for optimal, especially stepwise, release of the substrate or plate.

[0105] It is also conceivable that multiple sensors of different types be incorporated. In a particularly preferred embodiment, sensors for distance measurement and pressure measurement are incorporated in a particularly symmetrical and uniform distribution on the holding device and / or plate. This allows for discrete but surface-coverage distance and pressure measurements. Pressure measurement is particularly advantageous when the deformation element is a fluid, particularly a gas, or a gas mixture delivered through a pipeline.

[0106] If one or both holding devices are formed without curvature measuring means and / or without sensors, then the adjustment and / or control of curvature and / or curvature changes may be performed based on parameters determined by experience.

[0107] To ensure precise, and especially central, point-like contact, radially symmetrical positioning is used within the holding device.

[0108] The number of plate fixing elements during the bending process is preferably selected so that a 100 μm bend in the plate can be achieved without the plate being released from the holding device. In order to generate negative pressure, further vacuum elements are used, in particular, in addition to the vacuum orbital. These further vacuum elements are, among other things, sealing elements, especially sealing rings, and vacuum lips.

[0109] The position of the substrate or plate on the holding device can preferably be fixed across the entire surface of the substrate or plate. In a preferred embodiment, the bending of the substrate or plate is performed via compressed air at the center of the holding device.

[0110] The retaining device, in particular, has holes in its edge region for supplying compressed air or for actuators and vacuum orbitals. In this case, at least one negative pressure passage interrupting the retaining surface is provided in the ring section outside the retaining contour. The retaining area of ​​the retaining device can be reduced as needed, thereby reducing the contact area between the substrate or plate and the retaining device. Further possibilities for fixing the position of the retaining device and the substrate or plate are, in particular, • Mechanical positioning by clamping, and / or • Static positioning, and / or • Magnetic positioning, and / or • The gel pack is fixed in place.

[0111] The radially symmetrical fixing part is, for example, a vacuum track, a provided vacuum hole, a circular vacuum lip, or a comparable vacuum element capable of fixing a plate. The use of an electrostatic retaining device is also conceivable.

[0112] Plate and / or retaining device - protruding structure According to one embodiment, the retaining device and / or plate are provided with a protruding structure. The protrusions constitute a small number of support points for the substrate and / or plate, particularly evenly and continuously distributed. This avoids the possibility of contamination of the substrate and / or plate while maintaining stability. A corresponding protruding retaining device is described in this regard in International Publication No. 2015113641, which is referenced.

[0113] joining machine In the following process of this specification, a joining machine according to the present invention is described, which comprises two holding devices according to the present invention, at least one of which has a plate according to the present invention.

[0114] Preferably, in the vertical direction and position, both substrates are supported, particularly entirely, by corresponding plates. At the same time, the substrates are curved toward the bonding initiation point (the first contact point between the substrates at the start of bonding) by a single deformation means, particularly symmetrically with respect to the bonding initiation point, so that a convex surface can contact the bonding initiation point. In particular, the automated bonding process with bonding waves is preferably initiated by releasing at least one of the substrates and / or plates from the holding device.

[0115] In particular, embodiments of the bonding machine according to the present invention operate preferably at atmospheric pressure in a specified, particularly controllable atmosphere. The apparatus according to the present invention can preferably be operated under an inert gas. Preferably, the present gas atmosphere can buffer the contact process and thus prevent the contact surfaces from coming into contact prematurely or simultaneously at multiple points. Such measures prevent distortion. To control bonding during contact, it is conceivable to control the pressure in the bonding machine.

[0116] Method-Joining According to the present invention, the bending of the plate, and consequently the bending of the substrate fixed to the plate, can be precisely controlled during the bonding process.

[0117] A particularly independent aspect of the present invention involves applying a preload to both substrates, or to at least one of the substrates, before contact, which extends radially outward, particularly concentrically with respect to the center M of the contact surface of the substrates, thereby enabling contact that is as controlled as possible and simultaneously almost automatic. Such a preload is ensured by bending a plate on which the substrates are fixed. This affects only the start of contact, and after contact of one portion of the substrate, particularly the center M, the substrate is released while still fixed to the plate, and is therefore automatically supported by the plate and bonded to the opposing substrate, controlled by the preload. The preload is achieved by a controllable deformation of the plate by a deformation means, and therefore indirectly by a controllable deformation of the substrate, in which case the deformation means acts particularly on the side opposite to the bonding surface.

[0118] The release and pressure application processes may be carried out entirely, locally, or along a predetermined path. Accordingly, the curved or fixed elements are switched or controlled.

[0119] The bending of both substrates is performed in particular at a predetermined distance, which is reduced as the bonding wave progresses. The plate is completely released from the retaining device, especially for full contact of the substrates. In this case, the substrates remain fixed in position on the plate. For this reason, the retaining element of the retaining device is kept stationary, and the bending element is activated or remains activated. Especially when using fluid flowing from a nozzle, the lower plate floats as if on an air cushion, allowing for full contact of the substrates. The fluid pressure is adjusted and adapted by control means, thereby ensuring the process proceeds optimally.

[0120] In particular, to prevent the relative xy alignment of the substrates from changing due to plate displacement, the plate can be additionally held in an aligned xy position by a limiting element. The limiting element may be located outside the plate and can prevent the translational and / or rotational motion of the plate, and / or the limiting element is guided through a hole in the plate to prevent the translational and / or rotational motion of the plate. Since the plate according to the present invention only needs to have a very slight bend, a few micrometers of clearance between the hole in the plate and the limiting element is sufficient to ensure frictionless bending of the plate and to substantially prevent large displacement and / or rotation.

[0121] Another aspect of the present invention, particularly independent of a limiting element (or alternatively, a separate / additional capture element), is the mechanical capture of a plate completely freed from the positional fixation of a retaining device. If all the fixings of the upper retaining device are turned off, without such a limiting element the upper plate would fall from the upper retaining device. The limiting element prevents the fall and holds the position of the upper plate. This allows for the complete release or disengagement of the plate from the retaining device. The limiting element is particularly restrictive in the z direction.

[0122] The number of limiting elements is particularly 1 to 100, preferably 1 to 50, more preferably 1 to 25, even more preferably 1 to 10, and most preferably exactly 3 limiting elements. The limiting elements may be, for example, the following elements: • Screws, and / or • Pins, and / or • Anchor bolts, and / or • Thin metal sheets, and / or • Specially manufactured molded element.

[0123] After contact is made at the starting point of the bonding between the two substrates, the upper plate is completely released from the retaining device, and the upper substrate, still fixed in place on the plate, falls downward due to gravity on the one hand and due to the bonding force acting between the substrates along the bonding wave on the other hand.

[0124] The upper substrate is bonded to the lower substrate radially from the center or from the bonding start point toward the side edge. In this way, a radially symmetrical bonding wave, particularly extending from the center toward the side edge, is formed by the present invention. During the bonding process, the two substrates push the gas, especially air, present between them forward of the bonding wave, thereby creating a bonding interface free of gas. The upper substrate, supported by the plate, is actually positioned on a kind of air cushion when dropped.

[0125] The first / upper substrate, supported by the plate, is not further fixed in position after the start of bonding at the bonding start point. Therefore, apart from the fixing at the bonding start point and the fixing on the plate, it can move freely and may deform. The plate is selected to be flexible enough to minimize "runout" errors during bonding, while also providing sufficient support for the substrate to avoid bonding errors caused by excessive flexibility of the substrate.

[0126] After the bonding process is complete, the bonded substrate stack is protected by the upper and lower plates and can therefore be unloaded or further transported. Selectively, for example, after the bonding process is complete, the second / upper substrate is released from the plate. The bonded substrate stack remains fixed in place on at least the lower plate until the unloading process. The lower plate is likewise fixed again in place in the holding device by vacuum if necessary.

[0127] According to a preferred embodiment, the retaining device has a second vacuum area to ensure the overall positional fixation of the plate. This second vacuum area of ​​the retaining device can be formed, for example, in a cross shape, linear shape, or circular shape. Thus, the retaining device particularly has a first vacuum area in the edge region, preferably with a vacuum orbit on the outer annular surface, and a second vacuum area in the internal region, preferably on the inner annular surface.

[0128] Due to point-like contact at the center, the bonding wave, during bonding according to the present invention, preferably extends radially symmetrically from the center to the side edge, pushing a ring-shaped (concentric) air cushion forward during this process. In particular, along the bonding front of the substantially annular bonding wave, a bonding force large enough not to cause air bubble encapsulation is generated. The upper / second substrate is therefore positioned on a kind of air cushion during the bonding process.

[0129] Advantageously, all variable parameters are selected so that the bonding wave propagates at the most optimal speed possible given the existing initial and ambient conditions. In particular, under the existing atmosphere, especially at atmospheric pressure, the slowest possible speed of the bonding wave is advantageous. The propagation speed of the bonding wave is adjusted to be slower than 200 cm / s, more advantageously slower than 100 cm / s, more advantageously slower than 50 cm / s, extremely advantageously slower than 10 cm / s, and most advantageously 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.

[0130] All embodiments of the present invention described above can be carried out in a vacuum, particularly a low or high vacuum, in special modified embodiments. In a vacuum environment, the speed of the junction wave automatically becomes faster because the substrates bonded along the junction line do not have to overcome gas resistance.

[0131] Further advantages, features, and details of the present invention are evident from the following description of preferred embodiments and drawings. [Brief explanation of the drawing]

[0132] [Figure 1] This figure shows a first embodiment of the present invention, along with diagrams relating to pressure and bending processes. [Figure 2a] This figure shows a first embodiment of the apparatus according to the present invention in the first process step of the method according to the present invention. [Figure 2b] This figure shows the first embodiment in the second process step. [Figure 2c] This figure shows the first embodiment in the third process step. [Figure 2d] This figure shows the first embodiment in the fourth process step. [Figure 2e] This figure shows the first embodiment in the fifth process step. [Figure 3] This figure shows a second embodiment of the apparatus according to the present invention. [Figure 4a] This figure shows a third embodiment of the apparatus according to the present invention in the first process step. [Figure 4b] This figure shows a third embodiment in the second process step.

[0133] In drawings, the same reference numeral is used to indicate identical components or components with the same function.

[0134] Figure 1 shows a joining machine 13 according to the present invention in one process step of the present invention, and for ease of viewing, only the lower holding device 1u and the upper holding device 1o positioned opposite the lower holding device 1u of the joining machine 13 are shown. Other typical components of the joining machine 13 are not shown.

[0135] On the lower retaining device 1u, the lower plate 17u is fixed in place by a first plate surface 20, by a first fixing element 2 that extends in a ring shape from the lower retaining device 1u. The fixing element 2 is a passage that penetrates the retaining device 1u and is particularly loadable by fluid technology, preferably by pressure.

[0136] The lower plate 17u has a second fixing element 2' on a plate surface 21 facing the first plate surface 20, which can preferably be directly driven and / or connected to the first fixing element 2 by the lower retaining device 1u. Similarly, the upper retaining device 1o has an upper plate 17o, which can be fixed in position by a ring-shaped first fixing element 2 of the upper retaining device 1o.

[0137] In all illustrated embodiments, the second fixing element 2' of plates 17u, 17o is connected to the holding devices 1o, 1u via the fixing element connection 6'. If the fixing elements 2, 2' are vacuum fixing devices, the fixing element connection 6' is preferably formed as a passage that penetrates the plates 17u, 17o in particular. When the passage of the lower holding device 1u is evacuated, the fixing element connection 6' of the lower plate 17u is also evacuated, especially automatically. The same applies to the upper plate 17o and the upper holding device 1o.

[0138] While the fixing element 2 holds the plates 17u and 17o in place, the curved element 5 forms a curve inside the ring-shaped fixing element 2, so the plates 17u and 17o exist in a curved state.

[0139] The first (upper) substrate 4o is fixed to the upper plate 17o by the fixing element 2'. The second (lower) substrate 4u is fixed to the lower plate 17u by the fixing element 2'.

[0140] The first upper and lower diagrams of the bonding machine 13 in Figure 1 show the actual curvature 14u,14o of the substrates 4u,4o and / or plates 17u,17o, and the target curvature 15u,15o of the substrates 4u,4o and / or plates 17u,17o, as a function of x position. In addition to the first diagram, Figure 1 also shows a second diagram, which shows the pressure p that is reduced through the fixed element connection part 6' formed as a conduit and fixes the substrates 4u,4o to the plates 17u,17o. 1’ The diagram shows that each retaining device 17u, 17o has only one fixing element 2', specifically formed as an annular groove. Finally, the third diagram shows the pressure p1 applied to the periphery of the substrates 4u, 4o.

[0141] The drawing shows two types of limiting elements. The lower retaining device 1u is located on the first limiting element 19' which limits the simple translational movement of the plate 17u according to the present invention. For example, in one process step, all the fixing elements 2 may be turned off, allowing the lower plate 17u to float freely on an air cushion created by the fluid flowing out, particularly from the curved element 5.

[0142] The upper holding device 1o is located on a second limiting element 19 which is molded to prevent the plate 17o from falling, particularly when the substrate 4o fixed in place on the plate 17o falls.

[0143] In a preferred embodiment of the upper holding device 1o shown in Figure 3, the drive control of the second fixing element 2', which is independent of the first fixing element 2 (the passage to which pressure p1 is applied) of the holding device 1u, is performed by a particularly extendable fixing element connection 6'' (not shown in Figure 1). Pressure p1 is applied to the second fixing element 2' via a pressure pipeline. 1’ It can be loaded.

[0144] The following series of drawings illustrate in detail the process flow according to the present invention, for several process steps according to the first embodiment described above. For clarity, diagrams illustrating the pressure and curvature progression are omitted. Since the diagrams are omitted, the target and actual curvatures 15u, 15o, 14u, and 14o are not shown in further drawings. A schematic overview of the curvature progression can be seen in Figure 1.

[0145] Figure 2a shows a bonding machine 13 according to the present invention that brings into contact and bonds the opposing contact surfaces 4k of a first / upper substrate 4o and a second / lower substrate 4u. The bonding machine 13 consists of a lower holding device 1u and an upper holding device 1o. The holding devices 1u,1o can be formed to hold the first / upper substrate 4o and / or the first / upper plate 17o and the second / lower substrate 4u and / or the second / lower plate 17u, in which case the lower holding device 1u may be configured or equipped differently from the upper holding device 1o.

[0146] The upper holding device 1o preferably has a measuring hole 12 through which the plate 17o and / or substrate 4o can be measured, particularly from the back of the substrate holder 1o. When the substrate 4o is being measured, the plate 17o also has a corresponding measuring hole 12'. A sensor may be selectively placed in the measuring holes 12, 12'. The measuring holes 12, 12' are particularly located between the curvature changing means and the fixing means. The lower substrate holder 1u and / or lower plate 17u may optionally or additionally have corresponding measuring holes 12, 12'. The measuring holes penetrate the holding device 1 and extend particularly perpendicular to the holding surface 1s. Preferably, the measuring holes 12 are distributed on the upper surface at intervals of 180° or 120° from each other.

[0147] The holding devices 1u,1o have a holding surface 1s equipped with a plurality of fixing elements 2 and sensors 3,3'. The fixing elements 2 are exhausted through passages formed as fluid conduits and fix the plates 17u,17o in position. The distance sensors are distributed directly from the curvature changing means 5 to the fixing means. Thus, the distance sensors extend across a portion of the holding surface 1s.

[0148] A sensor 3' configured as a pressure sensor is placed in the area of ​​the fixing means, and this sensor measures the pressure p1 between the plates 17u, 17o and the holding devices 1u, 1o along the x position of the sensor 3.

[0149] The upper substrate 4o has an actual curvature 14o that exists due to gravity, while the lower substrate 4u is placed flat and therefore does not have an actual curvature 14u in the case of the present invention (although it actually has a very slight curvature). However, the actual curvature 14o caused by gravity can be considered negligibly small.

[0150] Figure 2b shows the bonding machine 13 in a different process step. The two substrates 4u and 4o are brought closer to each other by the relative movement of the two substrate holders 1u and 1o. Otherwise, the state is unchanged from that shown in Figure 2a.

[0151] Figure 2c shows the bonding machine 13 in another process step. In the illustrated example, the use of a curved element 5, which is a gas outlet opening through which gas at pressure p2 flows, brings both plates 17u, 17o, and consequently the substrates 4u, 4o, to the target curve, in which case the pressure is preferably adjusted by a distance sensor. For closed-loop / open-loop control, the pressure of a fixed element 2 can also be used, so that the fixed element can also take on the role of a curved means 5, 5' or a curve-changing means 5, 5', and therefore the fixed element is also counted as a curved means in this invention. The pressure value is particularly continuous and / or always, preferably separately for each region, and is closed-loop / open-loop controllable.

[0152] Figure 2d shows the bonding machine 13 in another process step. The two substrates 4u, 4o form a bonding wave that spreads radially outward as the substrates 4u, 4o approach each other. In this case, the curvature of the substrates 4u, 4o changes continuously (curvature modification means). In this case, the curvature change of the lower and / or upper plates 17u, 17o or the lower and / or upper substrates 4u, 4o is continuously monitored by distance sensors and, if necessary, corrected by the curvature element 5 and / or fixing element 2 to achieve the desired or set target curvature each time (curvature modification means). The important parameters are the radius of curvature R1 of the upper plate 17o or upper substrate 4o and the radius of curvature R2 of the lower plate 17u or lower substrate 4u at the point of the bonding wave.

[0153] The pressure in the rows of four inner fixing elements 2 extending in the circumferential direction is simultaneously reduced to p0 in the upper retaining device 1o and the lower retaining device 1u. As a result, the substrates 4u, 4o or plates 17u, 17o lose their positional fixation to the retaining surface 1s, particularly continuously from the inside to the outside, thereby allowing the pressure p2 from the curved element 5 to spread further.

[0154] By controlling the curvature and changes in curvature of the substrate, runout errors are minimized. In particular, unlike conventional techniques, the plate-substrate system has relatively high bending resistance, which allows the substrate to bond more stably to the opposing substrate, thus further reducing runout errors.

[0155] Figure 2e shows the bonding machine 13 in another process step. The two substrates 4u and 4o are bonded to each other under controlled conditions by reducing the pressure of the outermost row of fixing elements 2 of the upper retaining device 1o to p0. In particular, the upper plate 17o remains on the upper retaining device 1o. It is also conceivable that the upper plate 17o remains on the upper substrate 4o. In this case, the limiting element 19 should not be provided.

[0156] Another embodiment of the holding device according to the present invention is shown in another drawing.

[0157] Figure 3 shows an improved and preferred embodiment of the retaining device 1u and plate 17u according to the present invention, in which the positioning, which is performed particularly via a fixing element connector 6'' configured as a bellows or lip, is transferred from the retaining device 1u to the plate 17u. The fixing element connector 6'' is particularly expandable without interrupting the positioning of the substrate 4u relative to the plate 17u. In the case of electrostatic fixing, the fixing element connector 6'' may be, for example, a wire that maintains the potential between the retaining device 1u and the plate 17u. In the case of vacuum fixing as shown, the fixing element connector 6'' is expandable and particularly vacuum-dense bellows. If the fixing element connector 6'' is particularly centrally supported, the possible curved element 5 is located laterally to the fixing element connector 6''.

[0158] Figure 4a shows a retaining device 1u' configured similarly to retaining device 1u in the first process step according to the present invention. A distinguishing feature is the presence of a seal ring 18, particularly a ring-shaped arrangement, on the retaining device 1u'. A plate 17 is supported on the seal ring 18.

[0159] In this embodiment, a pin is positioned in the center of the retaining device 1u' as the curved element 5'. The pin penetrates the retaining device 1u' through the center and is movable in the z-direction relative to the retaining device. At the initial point, the plate 17u is supported together with the substrate 4u on the tip of the already raised curved element 5'. At the same time, the plate is further positioned on the undeformed seal ring 18. The plate 17u is substantially not yet curved.

[0160] Figure 4b shows the holding device 1u' in the second process step. By generating a vacuum along the vacuum path (passage, fixing element 2, fixing element connections 6', 6'', fixing element 2'), the plate 17u is attracted downward at its edges. This deforms the easily deformable elastic seal ring 18, sealing the plate to the holding device 1u. In the bonding process according to the present invention, after the substrate 4u is brought into contact with the substrate 4o (not shown), the vacuum path overflows again, thereby enabling an improved and optimized bonding process for the substrate 4u.

[0161] The embodiments shown in Figures 3a and 3b can be considered as kinematically inverted versions of the embodiments shown in Figures 1 to 2e. In particular, this embodiment is characterized in that the plate 17u is attracted downward at its periphery by generating a vacuum that acts especially on its periphery, whereas in the embodiments described above, the deformation of the plate 17u in the region of the curved element 5 was explained by the distribution of fluid flowing through the curved element 5 due to the force applied by the curved element 5. [Explanation of symbols]

[0162] 1o Upper retaining device 1u,1u' Lower retaining device 1s holding surface 2,2' Fixed element 3 sensors 4o First / upper substrate 4u Second / Lower Board 4a Board holding surface 4k contact surface 5.5' curved element 6',6'' Fixed element connection section 12 measuring holes 13 Joining machine 14u,14o Actual curvature 15u,15o target curvature 16u, 16o Pressure progression 17o Upper plate 17u Lower plate 18 sealing rings 19,19' Restriction element 20 First plate surface 21 Second plate surface p1,p 1’ pressure

Claims

1. A method for joining a first substrate to a second substrate at the mutually opposing contact surfaces of the first substrate and the second substrate, wherein the first substrate is held in a first holding device, the second substrate is held in a second holding device, and the second holding device has a lower plate positioned between the second substrate and the surface of the second holding device, The second substrate is deformed with respect to the second holding device together with the lower plate before bonding, during bonding, or both before and during bonding, and the second substrate is deformed by the deformation of the lower plate, the thickness of the lower plate being 0.1 mm to 10 mm. Multiple distance sensors are used as curvature measuring means, and the curvature of the substrate or plate is determined from the distance between the substrate and the holding device, or from the distance between the plate and the holding device. Multiple distance sensors are distributed along the holding surface to enable good closed-loop or open-loop control of the deformation, including curvature or curvature changes. A method characterized by the following features.

2. The method according to claim 1, wherein a first plate is positioned between the first substrate and the first holding device, and the first substrate is deformed together with the first plate with respect to the first holding device before bonding, during bonding, or before and during bonding.

3. The method according to claim 1 or 2, wherein the deformation is set or controlled or set and controlled such that, before the contact surfaces of the first substrate and the second substrate come into contact, the deformation is mirror-symmetric or concentric or mirror-symmetric and concentric with respect to the contact surfaces of the first substrate and the second substrate.

4. The method according to claim 1 or 2, wherein the deformation of the second substrate due to a fluid pressure load is set or controlled, or set and controlled, by a bending element that loads the lower plate.

5. The method according to claim 2, wherein the first plate is fixed in position by first fixing means arranged in a ring shape around the first holding device.

6. The method according to claim 5, wherein at least one of the first substrate and the second substrate is fixed in position by a first fixing means of the first holding device or a second fixing means of the first plate and the lower plate connected to the second holding device.

7. The method according to claim 1, 2, 5, or 6, wherein the deformation of the second substrate and the lower plate is detected by a curvature measuring means including a distance sensor.

8. The method according to claim 1, 2, 5, or 6, wherein the radius of curvature of the lower plate is adjustable.

9. The method according to claim 2, wherein the first substrate is fixed by a first fixing means arranged in a ring shape in a region of the first substrate.

10. The method according to claim 5, wherein at least one of the first substrate and the second substrate is fixed in position by a second fixing means of the same type as the first plate and the lower plate, which is connected to the first fixing means of the first holding device or the second holding device.

11. The method according to claim 1, wherein the distance sensor is used as a curvature measuring means, and the curvature between a plurality of support points is interpolated or calculated.

12. An apparatus for joining a first substrate to a second substrate, with the contact surfaces of the first substrate and the second substrate facing each other, It has a first holding device for holding the first substrate and a second holding device for holding the second substrate, the second holding device comprising a lower plate, In the apparatus, the lower plate is positioned between the second substrate and the surface of the second holding device. The lower plate is provided with a curvature changing means for deforming it together with the second substrate relative to the second holding device, the curvature changing means being controllable during bonding, the second substrate being deformed by the deformation of the lower plate, and the thickness of the lower plate being 0.1 mm to 10 mm. Multiple distance sensors are used as curvature measuring means, and the curvature of the substrate or plate is determined from the distance between the substrate and the holding device, or from the distance between the plate and the holding device. The apparatus is characterized in that the plurality of distance sensors are distributed along a holding surface to enable good closed-loop or open-loop control of the deformation, including curvature or curvature change.

13. The apparatus according to claim 12, wherein a first plate is disposed between the first substrate and the first holding device, and the first substrate, together with the first plate, is formed to be deformable with respect to the first holding device before bonding, during bonding, or before and during bonding.

14. The apparatus according to claim 12 or 13, wherein at least one of the first holding device and the second holding device has at least one of a mechanical bending element and a fluid pressure loading means for setting or controlling or setting and controlling the deformation of the first substrate and / or the deformation of the second substrate.

15. The apparatus according to claim 13, wherein the first holding device has a first fixing means for fixing the position of the first plate, and the first fixing means is arranged in an annular manner around the first holding device.

16. The apparatus according to claim 15, wherein at least one of the first plate and the lower plate has a second fixing means connected to the first fixing means of the first retaining device and / or the second retaining device.

17. The apparatus according to claim 12 or 13, wherein the lower plate has a Young's modulus between 0.01 GPa and 1100 GPa.

18. The apparatus according to claim 13, wherein the deformation of the first substrate and / or the deformation of the second substrate is detected by a curvature measuring means including a sensor including a distance sensor.

19. The apparatus according to claim 13 or 18, wherein the radius of curvature of the lower plate is adjustable.

20. The apparatus according to claim 15, wherein at least one of the first substrate and the lower plate has a second fixing means connected to the first fixing means and / or the second fixing means of the first retaining device for fixing the first substrate and / or the second substrate.

21. The apparatus according to claim 12, wherein the distance sensor is used as a curvature measuring means, and the curvature between a plurality of support points is interpolated or calculated.

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