Method for determining displacement maps, method for adjusting parameters for a bonding process, and composite substrate produced using said parameters, and system for producing a composite substrate

Abstract

The invention relates to a method for providing a displacement map (6), preferably for the qualitative evaluation of a performed bonding process, comprising the following steps: providing a first substrate (1) and a second substrate (2); measuring the first substrate (1) to determine at least one first geometric variable, in particular a macroscopic and / or microscopic first geometric variable, and measuring the second substrate (2) to determine at least one second geometric variable, in particular a macroscopic and / or microscopic second geometric variable; bonding the first substrate (1) to the second substrate (2), forming a composite substrate (4); measuring the bonded composite substrate (4) to determine at least one measured third geometric variable; and providing at least one simulated third geometric variable for the bonded composite substrate (4) based on a composite model, wherein the simulated third geometric variable is simulated by an analysis and / or simulation device (8) according to the at least one first geometric variable, the at least one second geometric variable and a temporary displacement map (6'), wherein the temporary displacement map (6') is created by the analysis and / or simulation device (8) and can be used in the composite model to compensate for deviations between the simulated third geometric variable and the measured third geometric variable.

Description

[0001] Method for determining displacement maps, method for setting parameters for a bonding process, and composite substrate produced with such parameters and system for producing a composite substrate

[0002] The present invention relates to a method for determining displacement maps, a method for setting parameters for a bonding process, a composite substrate produced with such parameters and a system for producing a composite substrate.

[0003] Several methods exist in the state of the art for joining substrates, particularly wafers, together. This joining process is called bonding. Bonding can be divided into two large groups: permanent bonding and temporary bonding. In temporary bonding, the substrates are joined together so that at least one of the two substrates can be processed. The second substrate serves as a mechanically stabilizing carrier. After the first substrate, the product substrate, has been processed, it can either be transferred to a third substrate, cut along the carrier substrate, or removed from the carrier substrate. In any case, the carrier substrate is removed in one way or another, and the product substrate is thus only temporarily bonded. Precise alignment of the two substrates to one another is not important. If the two substrates are aligned to within half a millimeter, this is usually sufficient from a process engineering perspective.

[0004] In contrast, permanent bonding creates a permanent connection between two substrates. This permanent connection is usually based on a so-called direct bond. A direct bond is a direct connection between two substrates via their existing substrate surfaces, without the need for a melting process, phase transition, or diffusion. Direct bonds are often also referred to as fusion bonds. The first important application of direct bonds was the connection of two oxidized substrates, one of which was prepared using SmartCut® technology. In SmartCut® technology, ions, particularly hydrogen atoms, are shot into a certain depth of the substrate. The substrate surface is oxidized and bonded to a second substrate, which also has an oxidized substrate surface.An additional heat treatment ensures that the prepared substrate breaks along the implantation plane, allowing its upper portion to be removed. The remaining substrate surface is planarized and then sits on a buried oxide layer. Functional units such as microchips can then be manufactured in this remaining substrate surface. The existing oxide layer prevents leakage currents. This process has the advantage that after contacting the two substrates, known as pre-bonding, the composite substrate can be exposed to any desired temperature, since there are no functional units present in the substrates that could be damaged by the temperature.

[0005] There are now process steps in which a substrate already has functional units before it is directly bonded to a second substrate. The temperatures must be correspondingly lower. Another problem, which arises particularly for substrates that have already been processed and preferably already equipped with functional units, is that these substrates must be precisely aligned to the second substrate before direct bonding. Alignment is usually necessary because the functional units of one substrate must communicate with the functional units of the second substrate. Communication usually takes place via copper lines that extend from the functional units to the substrate surface, usually through an oxide layer. If these copper lines are created in silicon or silicon oxide, they are called through silicon vias (TSVs).Countless such TSVs exist on a substrate surface. TSVs are the most important, but not the only, structures that must be aligned.

[0006] Another serious problem, which has arisen particularly in recent years, is the local displacements between the substrate surfaces of the substrates to be joined, which arise during bonding. In direct bonding, one substrate, preferably the lower one, is fixed to a substrate holder, while the second substrate initially contacts the first substrate at a point, in particular centrally. After this point contact, the second substrate is brought into contact with the first substrate in a controlled, or sometimes uncontrolled, manner. Contact is made by the formation of a bonding wave that propagates from the contact point to the periphery. During the propagation of the bonding wave, partial areas of the substrate surfaces of both substrates can be shifted relative to one another. In particular, the areas directly in front of, along or behind the bonding wave are subject to correspondingly large displacement.This can lead to structures on the two substrates that are opposite each other and should have been connected to each other no longer making contact or only making contact with each other poorly.

[0007] The measurement and analysis of substrate surfaces has been a well-known method for evaluating the quality of various processes for years. However, this method is used to assess substrate surfaces after a coating, exposure, or etching process. This is particularly easy because the treated substrate surface is easily accessible to optical systems after the respective process. The method is most frequently used in the measurement and evaluation of structures in a photolayer created by a lithography process. An idealized model of the structures exists on the computer. The structures are then transferred into a photoresist using a lithography process. In photolithography in particular, diffraction phenomena or misorientation of the mask relative to the substrate can lead to suboptimal imaging of the photomask structures in the photoresist.By comparing the structures actually created in the photoresist with the ideal structures created by the computer, a displacement map can be generated. This displacement map consists of a set of displacement vectors at as many positions as possible. Each displacement vector indicates how the actual structure position deviates from the ideal structure position. By calculating the change in the displacement vectors as a function of location, corresponding distortion maps can then also be calculated.

[0008] A problem with the current state of the art is the fact that the displacement maps between the substrate surfaces of two bonded substrates are not necessarily directly accessible. After a bonding process, a transmission method must be used to examine the bonded substrate surfaces. For example, the use of infrared light and a corresponding infrared camera to illuminate two bonded silicon wafers would be conceivable.

[0009] In most cases, however, the substrates to be illuminated, mostly silicon substrates, are coated with layers, especially metallic

[0010] Layers, coated, or already contain functional units that also include metallic components. Since metals are not infrared-transparent, measuring the interface is difficult or even impossible.

[0011] The problem with the prior art, however, is how to bond the substrates together in such a way that they are connected to one another in a controllable, full-surface manner such that their aligned structures exhibit minimal, or in particular no, displacement relative to one another at every position. Therefore, all structures on a first substrate must be contacted and bonded to the corresponding structures on a second substrate with minimal error. The problem is not only that the structures deviate from an ideal position during manufacture, resulting in, in the worst case, each substrate having a displacement map that describes the deviation of the structures from their ideal positions, but also that these displacement maps can change during bonding due to the mechanical properties, particularly in front of, on, and behind the bond wave.In particular, the change in the displacements of the structures during the bonding process represents a serious problem for structure sizes in the micrometer and nanometer range.

[0012] The state of the art does not, or at least not sufficiently, solve the problem of determining the displacement maps between the two substrate surfaces of a bonded composite substrate.

[0013] The present invention therefore has the object of providing a quantitative evaluation for a bonding process which can be used independently of the material composition of the substrates bonded to one another and preferably does not require further measuring steps in order to optimize parameters for the bonding process based on the quantitative evaluation.

[0014] The present invention solves the problem with the method according to claim 1, with the method according to claim 12, with a composite substrate according to claim 13 and with a system according to claim 14. Further advantageous embodiments can be found in the dependent claims, the figures and the description.

[0015] According to a first aspect, a method for providing a displacement map, which is preferably used for the qualitative evaluation of a completed bonding process, is provided, comprising

[0016] - Providing a first substrate and a second substrate,

[0017] - Measuring the first substrate to determine at least one first geometric size, in particular a macroscopic and / or microscopic first geometric size, and the second substrate to determine at least one second geometric size, in particular a macroscopic and / or microscopic second geometric size,

[0018] - Bonding the first substrate to the second substrate to form a composite substrate, - Measuring the bonded composite substrate to determine at least one measured third geometric size,

[0019] - Providing at least one simulated third geometric size for the bonded composite substrate based on a composite model, wherein the simulated third geometric size is simulated on the basis of the composite model by means of an analysis and / or simulation device as a function of the at least one first geometric size, the at least one second geometric size and a preliminary displacement map indicating a local deviation from the desired ideal position, wherein the preliminary displacement map is created by means of the analysis and / or simulation device and can preferably be adapted in the composite model, in particular is adapted to compensate for deviations between the simulated third geometric size and the measured third geometric size,

[0020] - comparing the at least one simulated third geometric size with the at least one measured third geometric size, and

[0021] - Providing the preliminary displacement map as the displacement type for which the deviation between the simulated third geometric size and the at least one measured third geometric size is minimal.

[0022] Contrary to the prior art approach, the invention provides that the displacement map is determined based on a simulation that predicts the appearance or shape of the composite substrate. The simulation initially assumes the geometric prerequisites, i.e., the at least one first geometric size and the at least one second geometric size, of the first and second substrates.

[0023] The displacement map represents the respective local deviation between the intended relative position of the first substrate to the second substrate and the actually assumed relative position of the first substrate and the second substrate, in particular with regard to their substrate surfaces. The displacement map thus indicates by how much local sections of the first and second substrate were laterally offset from one another or bonded offset from their ideal position and are therefore not arranged congruently with one another. The displacement map can be understood as a two-dimensional vector arrangement which assigns the size and direction of the respective lateral offset to each sub-section between the first substrate and the second substrate. If the offset is zero, the first substrate and second substrate lie one above the other or offset from one another as desired in this sub-section.The sections to be bonded are arranged essentially congruent with one another. It has been shown that the locally occurring lateral or sideways displacements of the sections during bonding influence the geometry, i.e. the external shape of the composite substrate. Furthermore, it has surprisingly been shown that the displacement map can be determined by means of simulations if, taking into account the geometries of the first substrate and the second substrate, the predicted geometry is compared with the actual geometry of the composite structure using a composite model and the preliminary displacement maps are adjusted until the predicted geometry and the actual geometry essentially match. This makes it possible to determine the displacement map even for bonded composite substrates, in particular their interface between the first substrate and the second substrate, without transmission methods.

[0024] Preferably, the preliminary displacement map is adjusted at least once to find the preliminary displacement map with the minimum deviation between the simulated third geometry size and the at least one measured third geometry size.

[0025] For an unstructured first or second substrate, one imagines an idealized, perfect, highly symmetrical grid with equidistant grid lines on the substrate surface to be bonded. The grid lines represent the mechanically undistorted state of the substrate surfaces. During a bonding process between two unstructured substrates, a displacement of individual subregions occurs in front of, on, and behind the bonding wave. These displacements are caused by the mechanical forces that the advancing bonding wave exerts on its surroundings. For example, one can imagine the second substrate being fixed in a planar manner over its entire surface by a lower substrate holder. Parts of the substrate are therefore unable to shift due to displacement, bending, or rotation.However, the first substrate, dropped onto the second substrate, can certainly be compressed, stretched, rotated, or bent as the bond wave advances. These elastic displacements are minimal, but after passing through the bond wave, they are fixed by the direct bond forming behind the bond wave. If one now imagines the initially defined grids on both substrate surfaces, one can see that at least one grid, in particular the grid of the first substrate, is no longer idealized, perfect, and highly symmetrical. Its grid lines have been shifted. If the displacements change as a function of location, the corresponding distortions also arise.

[0026] A similar consideration also applies to structured substrates that, for example, have functional units or TSVs. In simple terms, one no longer needs to imagine a grid, but can orient oneself directly to the structures, especially those that need to be aligned.

[0027] The method is preferably applied to structured and / or unstructured first and second substrates. It is particularly advantageous to use unstructured substrates to develop a first, approximate model. Unstructured first and second substrates are inexpensive, in contrast to already processed first and second substrates. By conducting multiple test runs with unstructured first and second substrates, it is possible to calculate composite models in which at least the influence of the ambient temperature, the ambient pressure, the substrate thicknesses, the substrate warpage, and the locally varying substrate curvatures can be estimated. In particular, these models can then be used as initial models for comparatively expensive, structured substrates. The structured first and second substrates can then be used to refine the composite model.

[0028] The at least one first geometric variable and / or at least one second geometric variable and / or the third geometric variable preferably comprises the thickness as a function of position, the local curvatures as a function of position, and / or the global curvature of the first substrate, the second substrate, and / or the composite substrate. It is also conceivable that a geometric variable is understood to be a local displacement of the substrate surface that is externally accessible and measurable by a detector. Such a displacement can be related to the displacements at the bonding interface that are not externally accessible to a detector. It is also conceivable to measure the surface roughness of the substrate surface to be bonded as a function of position. In particular, the surface roughness can influence the movement of the bonding wave.Preferably, the thickness as a function of position, the local curvatures as a function of position, and the global curvature of the composite substrate are determined. Preferably, only the external, accessible properties of the composite substrate are measured, i.e., the local and global curvatures and the composite substrate thickness as a function of location. The measurement of the composite substrate is also referred to as the measurement of the outer shell of the composite substrate. In the further course of the text, this refers to the measurement of all externally accessible parameters of the composite substrate that preferably contribute to the geometric shape of the composite substrate. It is therefore preferably not necessary to examine the bonded interface between the two substrates using a transmission method. This proves to be particularly advantageous for substrates that are at least partially opaque to electromagnetic radiation.For example, many substrates are provided with metallic layers or metallic functional units which make transmission analysis using infrared impossible because metals absorb infrared radiators very well. In general, however, it can be assumed that an undesired shift of the substrate surfaces relative to one another occurred during an initial bonding process. Particularly in the case of substrates with structures, the structures on both substrates will therefore not yet be in optimal contact with one another, i.e. there will be a shift between the structures on the first substrate and the structures on the second substrate. This even makes it possible to adjust shifts which could not previously be quantified using the prior art. The measurement of the geometric variables is preferably carried out using imaging and / or interferometric methods and devices.

[0029] Preferably, a device is used which records a full-area interference pattern of a substrate surface, from which the displacements and / or curvatures of the substrate or the substrate stack can be deduced in a spatially resolved manner.

[0030] The resolution of the camera, which records the full-surface real-space image or interference image, also determines the accuracy of the method. The higher the camera's resolution, the more precisely the method according to the invention can be carried out.

[0031] The geometric dimensions are preferably measured by evaluating images from a digital camera, particularly with a CMOS or CCD sensor. To measure the geometric dimensions, the highest possible resolution and pixel density are necessary. The more pixels there are per unit area, the more accurately a geometric dimension can be determined. The number of pixels is best specified per unit line to give an idea of ​​how many pixels are in one spatial dimension. It is advantageous to specify the number of pixels per wafer diameter. The number of pixels per wafer diameter is greater than 1,000, preferably greater than 10,000, even more preferably greater than 25,000, most preferably greater than 35,000, and most preferably greater than 50,000.The resolution of the camera in megapixels (MP) is then greater than 1 MP, preferably greater than 100 MP, even more preferably greater than 625 MP, most preferably greater than 1225 MP, and most preferably greater than 2500 MP. The measurement of the geometric dimensions on a substrate surface is preferably carried out by recording an interference image. Illumination, in particular over the entire surface of a generally curved and / or distorted substrate surface, results in phase differences due to different path lengths, which lead to an interference image. The curvatures and / or distortions can then be deduced from the interference image. For bonding, the first substrate and the second substrate are preferably aligned with one another. The alignment is carried out using an appropriately provided alignment system (aligner). The alignment is carried out in particular with respect to predetermined alignment marks.The alignment marks are preferably located on the periphery of the substrates. If unstructured substrates are bonded together, precision alignment can be omitted, especially if there are no alignment marks on the substrates. The substrates can then only be aligned mechanically. However, it would certainly be conceivable to apply simple alignment marks to the unstructured substrates to prevent any influence of inaccurate, purely mechanical alignment from becoming part of the later calculated model.

[0032] In the bonded model, a two-dimensional displacement map is preferably inserted between the substrate surfaces of the simulated substrates to be bonded. This displacement map models the physical effect of the propagating bond wave. It mathematically describes how strongly the structures of the first substrate are displaced relative to the structures of the second substrate under specified initial and boundary conditions. For unstructured substrates, an imaginary grid is used. Ideally, the displacement map is described by a vector-analytic function, but in the simplest case, it can also be just a set of two-tuples. The first element of the two-tuple represents the position at the interface, while the second element of the two-tuple is a displacement vector. The displacement map can therefore also be presented in tabular form.The first column, specifically the left column, indicates the position at the interface, while the second column indicates the displacement vector. The displacement map thus allows for spatially resolved representation of how far a structure on the substrate surface of a first substrate is displaced from the structure on the substrate surface of a second substrate.

[0033] An absolute value of a displacement vector is between 0 nm and 100 pm, preferably between 0 nm and 10 pm, more preferably between 0 nm and 1 pm, most preferably between 0 nm and 100 nm, most preferably between 0 nm and 10 nm.

[0034] Preferably, the composite model is generated in an analysis and / or simulation device, for example, in a computer, with the aid of which a substrate stack can be simulated after bonding. Preferably, the term analysis and / or simulation device can refer to a (personal) computer, a virtual machine running on host hardware, a microcontroller, or an integrated circuit. Alternatively, the analysis and / or simulation device can be a real or virtual group of computers (the technical term for a real group of computers is a "cluster," the technical term for a virtual group of computers is a "cloud"). Preferably, the analysis device comprises a computing unit and a storage unit. A computing unit can consist of hardware and software elements, for example, a microprocessor or a field-programmable gate array. A storage unit orThe storage device can be implemented as a non-permanent main memory (e.g., random access memory) or as a permanent mass storage device (e.g., hard disk, USB stick, SD card, solid-state disk). Furthermore, it is also conceivable for the analysis device to comprise at least one server and utilize at least one platform or a network of multiple servers that mutually support each other in carrying out the method.

[0035] A substrate stack consists of at least two substrates. The use of substrate stacks with more than two substrates (multistacks) is also conceivable.

[0036] In this case, it is preferably provided that the measured geometric dimensions of the first and second substrates prior to bonding are used to generate simulated composite substrates in the analysis and / or simulation device. In addition, a displacement map is generated using the analysis and / or simulation device, which in turn can be used to calculate a simulated third geometric dimension. At the end of the calculation of the simulated third geometric dimension, the simulated third geometric dimension can be compared with the measured third geometric dimension. For example, the third geometric dimension is the entire external shape or geometry of the composite substrate. If both geometries or geometric dimensions are identical, it can be assumed that the preliminary displacement map corresponds to the actual displacement map. This method step will now be described in more detail.Preferably, the composite model is determined and prepared in a preparatory process step. One challenge is, on the one hand, determining the composite model and, on the other hand, finding the correct displacement map. This is made easier by bonding and measuring multiple composite substrates. The composite model is approximated in a preparatory process step through a large number of bonding processes and the measured variables, in particular geometric variables, measured during the bonding processes. Once the composite model has been established in the preparatory process step, a variation of the preliminary displacement map is preferably implemented in the analysis and simulation device until the simulated third geometric variable is identical to a measured third geometric variable. The determination of the composite model in the preparatory process step is discussed below.

[0037] It can be assumed that in an actual bond, the environmental parameters such as temperature, ambient pressure, atmosphere, etc. are the cause of the real displacement maps. In the model, it is therefore sufficient to simply vary the displacement map until the outer shell of the bonded, simulated substrate stack is identical to the outer shell of the measured substrate stack. Once this displacement map has been found, all environmental parameters can be automatically associated with it. The model therefore preferentially correlates only the displacement map with the outer shell of the simulated composite substrate, or more simply, with the simulated composite substrate.

[0038] In a first method, the model is calculated using simulated displacement maps, preferably using the finite element method (FEM) or the finite difference method (FDM). With known initial and boundary conditions of the individual substrates and a given displacement map, this is simply a problem of elasticity theory. Using the finite element method, it is easy to calculate how the substrate stack deforms for a given displacement map. However, FEM and FDM methods are relatively time-consuming.

[0039] In a second method, the model is calculated using a set of mathematical basis functions. The superposition of the basis functions, preferably linear, allows the calculation of a simulated, bonded substrate stack for a given displacement map. The basis functions have model parameters that can be found using appropriate methods, thus constructing the basis functions themselves.

[0040] In a third method, the model is calculated using artificial intelligence, in particular neural networks.

[0041] The basis functions or FEM models themselves have adaptable model parameters that are determined from the collected data sets, preferably through a minimization problem. Once these model parameters have been determined, a model is available that can be used to calculate the displacement maps from the fit parameters, or the fit parameters from the displacement maps.

[0042] During optimization, it is possible to use individual local displacements as fit parameters, as well as models for the local displacements (4-parameter models, 6-parameter models, HOWA, Zernike polynomials, Legendre polynomials, etc.) to reduce the number of variables. When using models, a greater or lesser residual error will remain, depending on the complexity of the model.

[0043] The following simplifications can be made during model creation. The symmetry of the system is preferably exploited when calculating the model parameters. For example, it is conceivable to assume the system's mechanical properties to be axially symmetric, neglecting the orthotropy that usually exists, thus significantly simplifying the calculation. The basis functions or FEM models are then used only to calculate a small portion of a surface. The remaining parts are calculated by exploiting and applying the symmetry.

[0044] It is also conceivable to neglect the original shapes and thicknesses of the individual substrates and simply use the standard thicknesses according to the so-called semi-specification.

[0045] The following additional information leads to a more detailed and complex composite model:

[0046] - Using all available information of the original substrates, i.e. the shape of the back / front sides combined with the measured local thickness and / or

[0047] - Use of known information about the layers on the substrate (e.g. metal layers, stressed oxide layers, etc.).

[0048] Preferably, the comparison is repeated iteratively for various preliminary displacement maps until the displacement map is determined. This allows the displacement map to be determined using a comparatively simple algorithm.

[0049] It is preferably provided that for a first parameter set that describes a first bonding process, the displacement map is determined and for a second parameter set that describes a second bonding process, a further displacement map is determined, further comprising;

[0050] - Compare the displacement map and the further displacement map and

[0051] - Creating a third set of parameters to be used for a third bonding process, whereby the parameter set depends on the comparison between the displacement map and the subsequent displacement map. This advantageously makes it possible to use the displacement maps to compare different bonding processes and their chances of success.

[0052] The first parameter set and / or the second parameter set and / or the third parameter set comprises at least one parameter, preferably the global, statistically averaged ambient temperature. Preferably, a temperature map of at least one substrate, preferably both substrates, is also recorded as a function of time and understood as a parameter, so that conclusions can be drawn about the thermal behavior of the temperature near the bonding wavefront during the progression of the bonding wave, as well as the upstream and downstream surface areas.

[0053] In a further improvement, the global, statistically averaged ambient pressure is measured and assigned to the parameter set.

[0054] In a further improvement, a bonding system has several flow sensors that are arranged radially symmetrically, preferably at equal angular intervals. The flow sensors are located within the plane through which the bonding interface runs. They point to the contact point where the bond began, in particular to the center of the two substrates. The task of the flow sensors is to measure the air flow that occurs as the bonding wave progresses. The bonding wave pushes the air located between the first substrate and the second substrate radially symmetrically outwards. The air cushion thus created between the first substrate and the second substrate influences how quickly the first substrate bonds to the second substrate. Therefore, the bonding behavior can also be influenced by changing the gas composition, for example.By adding very light elements such as helium, the gas kinetics and thus the associated mechanical behavior of the first and second substrates, in particular of the falling first substrate, can be influenced. Therefore, the measurement results of these flow sensors are also preferably part of the parameter set. In a further improvement, the atmospheric composition is determined and used as part of the parameter set. Of particular importance is the determination of the air humidity, i.e., the water content in the atmosphere. Experience has shown that air humidity has a massive influence on the bonding result. The water can condense on the substrate surfaces and thus contribute to an improvement in the bond quality, especially if the substrate surface is hydrophilic.

[0055] In a further improvement, the setting values ​​used by the deformation means used to deform at least one substrate are recorded during deformation. If the deformation means is a pin, the position of the pin, its speed and the force acting on the substrate are preferably measured as a function of time. The position is preferably determined directly by the step of a stepper motor, preferably by other measuring means. Speed ​​and acceleration result automatically as the first and second derivatives from the displacement-time diagram. The force is preferably recorded by a load cell. The load cell is either built into the pin or located on the side or behind the pin. In both of these cases, easy replacement is guaranteed.If the deformation medium is a nozzle, the flow velocity, pressure and volume flow of the escaping gas are preferably measured.

[0056] Preferably, a temporal development of the at least one parameter during the bonding process is determined by means of the at least one measuring device. This advantageously allows for the fact that at least certain parameters may change during the bonding process to be taken into account.

[0057] In particular, it is provided that a thickness of the first substrate and / or a thickness of the second substrate has a value between 100 nm and 5000 μm, preferably between 100 nm and 800 μm, and particularly preferably between 100 nm and 500 μm. The substrates to be bonded are therefore comparatively thin substrate layers. The substrates can have any desired shape, but are preferably circular. The diameter of the substrates is, in particular, industrially standardized. For wafers, the industry-standard diameters are 1 inch, 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 8 inches, 12 inches, and 18 inches.

[0058] Preferably, subsegments of the displacement map are simulated. For example, subsegments are understood to be sections in a grid of the displacement map or subsections of the displacement map. This can, for example, increase the significance or relevance of individual subsegments.

[0059] Preferably, machine learning is used to determine the bonding model and / or the at least one parameter for the third parameter set. In particular, it is conceivable that the determined displacement maps are stored together with the bonding process parameters and used as training data to optimize the bonding model or the parameter settings during the bonding process. The training data is preferably shared globally, for example, via a cloud, to support the analysis and / or simulation systems in finding the optimal bonding model or the optimal bonding parameters.A further subject matter of the present invention is a method for setting parameters for a bonding process, wherein a displacement map is created for setting the parameters in order to determine parameters for the bonding process based on the displacement map, wherein the displacement map is provided by means of a method according to the invention. All advantages and properties described for the method for providing the displacement map apply analogously to the method for setting the parameters and vice versa. A further subject matter of the present invention is a composite substrate produced from a first substrate and a second substrate in a bonding process using the parameters set according to a method according to the invention. All advantages and properties described for the method for setting the parameters apply analogously to the composite substrate and vice versa.A further object of the present invention is a system for measuring and / or bonding a first substrate, a second substrate to form a composite substrate or a composite substrate:.

[0060] - comprising at least one analysis and / or simulation device suitable and designed to carry out the method according to one of the preceding claims. All advantages and properties described for the method for providing the displacement map apply analogously to the system, and vice versa. Preferably, the system comprises means for bonding. For example, a bonder is designed to carry out the inventive measuring method.

[0061] Particularly preferably, the system comprises at least one measuring device. The measuring device is preferably designed to determine a parameter during the bonding process and / or a first, second, and / or third geometric parameter.

[0062] The method according to the invention can be applied directly after bonding. However, it is also conceivable that the method is applied only after mechanical and / or chemical processing, in particular re-thinning, of the bonded substrate stack. Processing the substrate stack changes the geometric parameters, such as the thickness and / or curvature. It can be assumed that the displacement map at the bonding interface is not affected by such subsequent processing of the substrate stack.

[0063] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

[0064] They show in:

[0065] Figure 1 shows a process flow of a method according to a preferred embodiment of the present invention and

[0066] Figure 2 shows a schematic representation of some process steps of the process from Figure 1. In the figures, identical components or components with the same function are identified by the same reference numerals.

[0067] Figure 1 shows a process flow of a method according to a first preferred embodiment of the present invention. In a first method step 10, a first substrate 1 and a second substrate 2 are selected. In a second method step 20, the first substrate 1 and the second substrate are measured, in particular to determine at least one first geometric parameter for the first substrate 1 and to determine at least one second geometric parameter for the second substrate 2. In an optional, third method step 30, the first substrate 1 and the second substrate 2 are aligned with one another, preferably in an alignment device which, for example, holds the first substrate 1 with a first holding device and the second substrate 2 with a second holding device and positions them with respect to one another. In a fourth method step 40, the first substrate 1 and the second substrate 2 are joined to one another, i.e. connected.In a fifth method step 50, the bonded composite substrate, i.e., the composite substrate, is measured to determine a measured third geometric variable. In a sixth method step 60, a composite model is generated in an analysis and / or simulation device, which includes a displacement map or is based on the use of a displacement map. The analysis and / or simulation device comprises at least one microprocessor and is, for example, a computer. It is also conceivable that the analysis and / or simulation device is part of a network and / or cloud-based.

[0068] In a seventh method step 70, a simulated third geometric size for a simulated composite substrate is determined or calculated using the first geometric size and the second geometric size determined in the second method step 20 and the simulated displacement map from the sixth method step 60. In an eighth method step 80, the at least one measured third geometric size is compared with the simulated at least one third geometric size in order to determine the extent to which the simulated composite substrate corresponds to or deviates from the real, i.e., bonded and measured, composite substrate.If the simulated composite substrate matches the real composite substrate, particularly with regard to the simulated third geometric size and the measured third geometric size, the displacement map simulated in the analysis and / or simulation device is identical to the real displacement map, and the method is terminated with the ninth method step 90. The simulated displacement map is then the final displacement map provided by the method.

[0069] If the simulated composite substrate and the simulated composite substrate are not identical, the last displacement map from the sixth process step 60 is modified in a supplementary process step 81, in particular by varying it using a mathematical method, thus resulting in a new displacement map, which is used to restart the simulation. Optionally, it is possible to restart the process for a specified model with new substrates. In this case, the process begins again at the first process step 10.

[0070] Figure 2 schematically illustrates the measurement and simulation process steps shown in Figure 1. Components that occur twice in a process step are always identified only once with a reference symbol. The process steps not performed in the analysis and / or simulation facility are shown in the left column, and the process steps performed in the analysis and / or simulation facility are shown in the right column.

[0071] List of reference symbols:

[0072] 1 first substrate

[0073] 2 second substrate

[0074] 4 composite substrates

[0075] 5 simulated composite substrates

[0076] 6 preliminary displacement map 6' displacement map

[0077] 8 Analysis and / or simulation facility

[0078] 10 first procedural step

[0079] 20 second process step 30 third process step

[0080] 40 fourth procedural step

[0081] 50 fifth procedural step

[0082] 60 sixth procedural step

[0083] 70 seventh process step 80 eighth process step

[0084] 81 additional procedural step

[0085] 90 ninth procedural step

Claims

Claims 1 . A method for providing a displacement map (6), which is preferably used for the qualitative evaluation of a completed bonding process, comprising - providing a first substrate (1) and a second substrate (2), - measuring the first substrate (1) to determine at least one first geometric size, in particular a macroscopic and / or microscopic first geometric size, and the second substrate (2) to determine at least one second geometric size, in particular a macroscopic and / or microscopic second geometric size, - bonding the first substrate (1) to the second substrate (2) to form a composite substrate (4), - measuring the bonded composite substrate (4) to determine at least one measured third geometric size, - Providing at least one simulated third geometric size for the bonded composite substrate (4) based on a composite model, wherein the simulated third geometric size is simulated on the basis of the composite model by means of an analysis and / or simulation device (8) as a function of the at least one first geometric size, the at least one second geometric size, and a preliminary displacement map (6') indicating a local deviation from the desired ideal position, wherein the preliminary displacement map (6') is created by means of the analysis and / or simulation device (8) and can preferably be adapted in the composite model in order to compensate for deviations between the simulated third geometric size and the measured third geometric size, - comparing the at least one simulated third geometric size with the at least one measured third geometric size, and - Providing that preliminary displacement map (6') as displacement map (6) for which the deviation between the simulated third geometric size and the at least one measured third geometric size is minimal.

2. The method according to claim 1, wherein the preliminary displacement map (6') is adjusted at least once to find the preliminary displacement map (6') with the minimum deviation between the simulated third geometry size and the at least one measured third geometry size.

3. Method according to one of the preceding claims, wherein the composite model is determined and provided in a preparatory method step.

4. Method according to one of the preceding claims, wherein the at least one first geometric variable and / or the at least one second geometric variable and / or the third geometric variable comprises a thickness as a function of a position, a local measured curvature as a function of a position and / or the global curvature of the first substrate (1) and / or the second substrate (2).

5. Method according to one of the preceding claims, wherein the displacement map (6) is determined for a first parameter set describing a first bonding process and a further displacement map is determined for a second parameter set describing a second bonding process, further comprising: - Compare the displacement map and the further displacement map and - Creating a parameter set that is used for a third bonding process, wherein the parameter set depends on the comparison between the displacement map (6) and the further displacement map.

6. Method according to one of the preceding claims, wherein at least one parameter of the first parameter set and / or the second parameter set is determined during the bonding process by means of at least one measuring device.

7. The method according to claim 6, wherein a temporal development of the at least one parameter during the bonding process is determined by means of the at least one measuring device.

8. The method according to one of claims 4 to 6, wherein the at least one parameter of the first parameter set comprises a temperature, a pressure and / or a flow variable during bonding, preferably measured with the one measuring device.

9. Method according to one of the preceding claims, wherein the first substrate (1) and the second substrate (2) are unstructured.

10. The method according to any one of the preceding claims, wherein a thickness of the first substrate (1) and / or a thickness of the second substrate (1) has a value between 100 nm and 5000 pm, preferably between 100 nm and 800 pm and particularly preferably between 100 nm and 500 pm.

11. A method for setting parameters for a bonding process, wherein displacement maps (6) are created to set the parameters in order to determine parameters for the bonding process based on the displacement maps (6), wherein the displacement maps (6) are provided by means of a method according to one of the preceding claims.

12. A composite substrate (4) made from a first substrate and a second substrate in a bonding process using the parameters set according to a method according to claim 11.

13. System for measuring a first substrate (1), a second substrate (2) and / or a composite substrate (4) comprising at least one analysis and / or simulation device (8) which is suitable and designed to carry out the method according to one of the preceding claims.

14. Plant according to claim 13, wherein the plant comprises means for bonding the first substrate (1) and the second substrate (2) to form a composite substrate (4), in particular for carrying out a method according to claim 11.

15. System according to claim 13 or 14, wherein the system comprises means for recording a full-area interference image.

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