Method for bonding a first substrate to a second substrate, device for bonding, substrate holder for such a device, and sensor element

Abstract

The invention relates to a method for bonding a first substrate to a second substrate (10), the first substrate having a main section and the second substrate (10) having an auxiliary section, a bonding wave advancing in a bonding direction being formed between a first sub-section and a second sub-section during bonding of the first substrate to the second substrate (10):-in the first sub-section, the second sub-section is provided with an auxiliary section, the first substrate and the second substrate (10) are connected to each other, and-a second sub-section in which the first substrate and the second substrate (10) are still to be connected, a sub-region of the second substrate (10) in the second sub-section being offset in height with respect to a sub-region of the second substrate (10) in the first sub-section in a direction perpendicular to the main extension plane, and-a sub-region of the second substrate (10) in the second sub-section being offset in height with respect to a sub-region of the second substrate (10) in the second sub-section. Wherein, before and / or during the bonding, light is directed onto a surface of the object and reflected in order to determine the state of the object, and the light reflected by the surface is measured by means of a sensor element (15) for determining the distance between the sensor element (15) and the surface, and the distance (a) between the sensor element (15) and the surface is determined.

Description

Technical Field

[0001] The present invention relates to a method for bonding a first substrate to a second substrate, an apparatus for bonding, a substrate holder for such apparatus, and a sensor element. Background Technology

[0002] In the semiconductor industry, substrates of different sizes, shapes, and materials are typically joined together. This joining process is called bonding. Bonding is broadly categorized into permanent bonding and temporary bonding. In permanent bonding, a bond that can no longer be detached is created between the two substrates. This permanent connection is achieved through interdiffusion of metals, through cation-anion migration in anodic bonding, or through the formation of covalent bonds between oxides and / or semiconductor materials in molten bonding. In temporary bonding, so-called bonding adhesives are primarily used. These are adhesives applied to the surfaces of one or both substrates via a coating method to act as an adhesion promoter between the substrates.

[0003] In fusion bonding, two substrates are joined together in an initial detachable connection, a pre-bonding. This pre-bonding primarily results from van der Waals bridging connections between two high-purity, flat, and as defect-free and particle-free substrate surfaces in close contact with each other. Hybrid bonding is a subtype of fusion bonding. Hybrid bonding involves the connection of two substrate surfaces, each consisting of an electrical substrate region and a dielectric substrate region. The corresponding associated (dielectric) substrate regions are connected to each other by means of fusion bonding (pre-bonding). When the pre-bonding is converted into a permanent bond, a permanent electrical contact is formed between the electrical substrate regions of the substrates.

[0004] In all bonding methods, a bonder is used to join the substrates to be bonded together. The two substrates to be bonded may undergo pretreatment, such as surface activation, cleaning steps, orientation steps, until the actual pre-bonding step occurs.

[0005] In pre-bonding, the substrate surfaces are brought into contact with each other on a very small surface area. In other words, the bonding reaction begins, and the subsequent bonding reaction, i.e., the formation of the bridging connection, can proceed without external energy delivery. The bonding process proceeds continuously through the propagation of the bonding wave. The theoretical background is described in US 7,479,441 B2, US 8,475,612 B2, US 6,881,596 B2, and WO2014 / 191 033.

[0006] If a bonding wave is induced at the center in two identical, unstructured substrates, ideally the bonding wave will travel along the substrate radius as a concentrically growing circular wavefront. Structured substrates, impurities, etc., alter the travel of the bonding wave. Under suboptimal conditions, unbonded regions (voids) may arise between the two substrates, for example, due to gas inclusions, particulate inclusions, etc.

[0007] Under suboptimal conditions, the anisotropy of the substrate structure or substrate material can alter the propagation process of the bonding wave. Any variation in the propagation process of the bonding wave can be measured by those skilled in the art as orientation errors at the bonded substrate stack. Furthermore, bonding errors may arise due to orientation errors (particularly from the following error components: scaling error, run-out-Fehler error), rotational errors, translational errors, residual errors, and temperature compensation errors. Undetected or non-critical errors in individual substrates, or especially in functional units fabricated using thin-layer techniques, are additive during error propagation and are only detectable and quantifiable after the pre-bonding process.

[0008] Although substrates can be oriented very precisely relative to each other using orientation facilities, substrate distortion can occur during the bonding process itself. Due to this distortion, functional units do not necessarily need to be correctly oriented relative to each other at all locations. Orientation inaccuracies at specific points on the substrate can result from distortion, scaling errors, lensing errors (magnification or reduction errors), etc.

[0009] In the semiconductor industry, all topics related to this issue are categorized under the term "overlay." For example, an introduction to this topic can be found in the following literature: Mack Chris, Fundamental Principles of Optical Lithography - The Science of Microfabrication, WILEY, 2007, reprinted 2012.

[0010] Each functional unit is designed in a computer before the actual manufacturing process. For example, printed wires, microchips, MEMS, or any other structure that can be manufactured using microsystems technology can be designed in a CAD (computer-aided design) program. However, during the manufacturing of functional units, discrepancies always exist between the ideal functional unit constructed in the computer and the actual functional unit manufactured in the cleanroom. These differences are primarily attributed to hardware limitations, i.e., engineering issues, but very often to physical limitations.

[0011] Therefore, the resolution of structures fabricated by photolithography is limited by the aperture size of the photomask and the wavelength of the light (electromagnetic radiation) used. Mask distortion is directly transferred to the photoresist, and thus to the fabricated structure. Motion devices, such as guides, along with drive systems coupled to them, can approach reproducible positions within pre-defined tolerances, and so on. Therefore, it is not surprising that the functional units of the substrate may not be exactly the same as the structure designed in the computer.

[0012] Therefore, all substrates already have a non-negligible deviation from the ideal state before the bonding process.

[0013] If we now compare the positions and / or shapes of two opposing functional units on two substrates, namely the first and second substrates, assuming that neither substrate will be distorted during the bonding process, it is found that there is usually an imperfect overlap of the functional units because the functional units deviate from the ideal computer model due to the aforementioned errors. The most common errors are shown below: https: / / commons.wikimedia.org / wiki / File%3AOverlay_-_ typical_model_terms_DE.svg May 24, 2023, and Mack Chris, Fundamental Principles of Optical Lithography - The Science of Microfabrication, Chichester: W.J. Ley, p. 312, 2007, reprinted 2012. Based on these illustrations, a rough distinction can be made between global and local, or symmetric and asymmetric, overlay errors. Global overlay errors are uniform and therefore independent of position. Global overlay errors produce the same deviation between two opposing functional units, independent of position. Classical global overlay errors are errors I and II, which are generated by the translation or rotation of two substrates relative to each other. The translation or rotation of these two substrates produces a corresponding translation or rotation error for all the respective opposing functional units on the substrates. Local overlay errors are position-dependent and mainly arise from elastic and / or plastic problems, in this case primarily caused by continuously propagating bonding waves. Of the overlay errors shown, errors III and IV are primarily referred to as "run-out" errors. These errors are mainly caused by the twisting of at least one substrate during the bonding process. Due to the twisting of at least one substrate, the functional units of the first substrate are also twisted relative to the functional units of the second substrate. However, errors I and II can also be caused by the bonding process, and errors III and IV may often be strongly superimposed, making these errors difficult to identify or measure.

[0014] A device already exists in the prior art that can at least partially reduce local distortion. This involves local correction using active control elements. Such a device is described, for example, in EP 2 656 378 B1.

[0015] Other solutions for correcting "runaway" errors already exist in the prior art. US 2012 0 077329 A1 describes a method to achieve desired orientation accuracy between functional units of two substrates during and after bonding. In most cases, the resulting "runaway" error becomes stronger radially symmetrically around the contact site, thus increasing from the contact site to the circumference. In most cases, this is an enhancement of the linear increase in "runaway" error. Under certain conditions, "runaway" error can also increase non-linearly.

[0016] Under particularly favorable conditions, the "jump" error can be determined not only by the corresponding measuring device (EP 2 463 892B1) but also described, at least approximately, by a mathematical function. Since the overlay error represents translation and / or rotation and / or scaling between well-defined points, it is preferably described by a vector function. Generally, this vector function involves the function f: R² -> R², and thus involves a mapping rule that maps the two-dimensional domain of the position coordinates to the two-dimensional domain of the "jump" vector. Although a precise mathematical analysis of the corresponding vector field is not yet possible, assumptions can still be made about the function's properties. The vector function is likely at least a C ^ n >= 1 function, and therefore at least once continuously differentiable. Because the "jump" error increases from the contact point to the edge, the divergence of the vector function may not be zero. Therefore, the vector field is likely the source field.

[0017] Many errors, such as gas clip or scaling errors, are primarily attributed to the pre-bonding step, particularly to the propagation process of the bonding wave or the nature and / or configuration and / or functionality of the corresponding substrate holder. Methods for providing a quantitative description of the propagation process of the bonding wave are known in the art.

[0018] The most common method for monitoring the bonding process is to use optical mechanisms, especially camera systems, and particularly transmitted light methods, especially observing the propagation of the bonding wave in the infrared spectrum. The substrate must have sufficient transparency for observing the bonding wave. While these methods are common practice, they have drawbacks. Not all substrates are suitable for transmitted light methods; in particular, metallization can hinder the observability of the bonding interface formed when joining the surfaces of two substrates to be bonded. Furthermore, doping in the semiconductor substrate can affect the transmittance of electromagnetic radiation. Additionally, transmitted light methods place special requirements on all substrate holders, as these must also be transmissive to radiation, which can also cause problems with the reproducibility of the results.

[0019] All currently known techniques for measuring the propagation of bonding waves involve directly observing the pre-bonding process through the substrate or measuring the effect of the attraction force during substrate bonding. Sometimes, precise, commercially available measurement methods or devices are unavailable that can observe the propagation of bonding waves in all substrates with high positional resolution, independent of the substrate's material properties, and / or can be used to calibrate bonding equipment. Summary of the Invention

[0020] Therefore, the object of the present invention is to disclose an improved apparatus and method for measuring and influencing bonding waves in the fusion bonding of two substrates.

[0021] The present invention achieves the stated objective by means of the method for bonding a first substrate to a second substrate according to claim 1, the bonding apparatus according to claim 11, the substrate holder according to claim 14, and the sensor element according to claim 15. Advantageous improvements of the invention are given in the dependent claims. All combinations consisting of at least two features described in the specification, claims, and / or drawings also fall within the scope of the invention. Values ​​within the given range of values ​​that fall within the mentioned boundaries should also be considered as boundary values ​​and can be claimed in any combination.

[0022] According to a first aspect, a method for bonding a first substrate to a second substrate is proposed, wherein the first substrate has a main segment and the second substrate has an auxiliary segment.

[0023] During the bonding of the first substrate and the second substrate, a bonding wave is formed between the first sub-segment and the second sub-segment, propagating along the bonding direction.

[0024] -- In the first sub-segment, the first substrate and the second substrate are connected, and

[0025] -- In the second sub-segment, the first substrate and the second substrate still need to be connected.

[0026] The sub-region of the second substrate in the second sub-section is offset in height from the sub-region of the second substrate in the first sub-section in a direction perpendicular to the main extension plane.

[0027] Before and / or during bonding, in order to determine the state of the object, light is directed onto the surface of the object and reflected, and the light reflected by the surface is measured by means of a sensor element used to determine the distance between the sensor element and the surface, and the distance between the sensor element and the surface is determined.

[0028] Contrary to methods known in the prior art, light reflected from the surface of the object, for example, by the back side of the second substrate, is used to determine the state of the object, for example, the second substrate. This method proves particularly advantageous because it allows for the measurement of different objects or object types with different optical properties, especially when said object or object type has a certain reflectivity to the light used. Here, it is advantageous to structurally limit the method to a method by which multiple objects can be measured using the same sensor element. For example, it is feasible to determine the orientation of the substrate holder for the first substrate before bonding, in addition to determining the state of the second substrate during bonding, also using the same sensor element. All of this can be ensured by a single structural measure at the bonding device, particularly by a sensor element for detecting reflected light. For example, it is not feasible to propose a transmission method for the second substrate, because the substrate holder for the first substrate or the first substrate is generally not transmissible. Therefore, alternative measurement methods are needed. Preferably, the method is set up for determining the state of two different objects.

[0029] Furthermore, determining the spacing by means of reflected light has thus proven particularly advantageous, as it provides the feasibility of determining the spacing between the sensor element and the surface with the greatest possible accuracy and process reliability. In particular, the current position or orientation of the object, such as the second substrate or at least a sub-segment of the substrate holder of the first or second substrate, before or during bonding, especially preferably in the region of the bonding wave or in the region adjacent to the bonding wave, is understood as state determination. The process of determining the state using reflected light has proven particularly advantageous here, as it is thus feasible even when the object, such as the second substrate, is opaque to the wavelength used to inspect the second substrate. Therefore, the method according to the invention has proven particularly advantageous compared to, for example, methods that involve the transmission of the second substrate. This processing method known from the prior art is ultimately limited to having a second substrate with a certain degree of transparency to the wavelength used. Hereinafter, the second substrate and the upper substrate on one side are used synonymously, and the first substrate and the lower substrate on the other side are used synonymously.

[0030] State determination also includes, for example, the detection of at least locally the spacing between the main segment of the first substrate and the auxiliary segment of the second substrate. It is also conceivable that the object, such as the second substrate, is modified at its surface to improve its reflectivity, particularly compared to an unmodified surface. For example, a coating that enhances reflectivity can be conceivable.

[0031] Preferably, at least one optical fiber element is used as a component of the sensor element, and preferably, a fiber optic spacing sensor is used as the sensor element. The use of the fiber element allows light to be guided to an area relatively close to the second substrate or object, while a light source, for example, that generates heat, can be as far away from the second substrate or object as possible. This advantageously prevents the light source and its heat from potentially damaging the second substrate or the object to be measured. It is also conceivable that, for spacing determination, an interferometric sensor system or a system in which the propagation time of light pulses is determined by superposition of light pulses and subsequently used for spacing determination is used. This similarly allows the recording of particularly minute movements or spacing changes. Preferably, the light used is a laser. Here, a preferred wavelength can be advantageously used, which facilitates maximum possible reflection at one or more different objects and / or facilitates coupling the input to the fiber element.

[0032] A particular advantage of fiber optic technology is its ability to dramatically increase the number of sensor elements per unit area, i.e., the sensor element areal density, which enables an extreme improvement in resolution. Sensor elements used in the prior art are very large and bulky because they are mostly mounted together with electronic devices at the substrate holder. Therefore, it is preferable to provide fiber elements with fiber ends for signal reception. Furthermore, the fiber element includes signal transmission sections, which are configured, for example, for signal conduction. Here, the signal transmission sections are preferably configured for optical conduction and / or for transmitting electrical signals. This allows the fiber ends to be advantageously located at or near the substrate holder. This increases the density of fiber ends in the region of the substrate holder. This has a positive impact on positional resolution. With the signal transmission sections, evaluation devices can be placed at a sufficiently large distance from the fiber ends. In other words, the placement of signal converters or evaluation devices at the substrate holder can be advantageously avoided.

[0033] A preferred sensor element is a fiber optic spacing sensor. The fiber optic spacing sensor comprises at least one radiation source, an optical fiber, and an evaluation unit. The optical fiber comprises at least two fibers or two fiber bundles. The fibers serve as conductors for coupling radiation from the radiation source into the substrate, and also for coupling out-of-range measurement signals and transmitting these signals to the evaluation unit. The evaluation unit calculates the propagation process of the bonded wave, particularly from changes in measurements taken by the fiber optic spacing sensor, which is specifically calibrated.

[0034] The signal measured by the fiber optic pitch sensor is preferably an intensity change, which is related to the pitch or pitch variation. The distance between the fiber and the reflective surface is measured via a characteristic function of the reflection intensity. In other words, the fiber optic pitch sensor is used for non-contact measurement of the pitch or fine movement between the sensor and the surface to be probed, particularly the back side of the substrate or the surface of the substrate holder. Here, the pitch difference or pitch can be detected non-contactly at frequencies below 5 nanometers and / or above 100 MHz using the fiber optic pitch sensor. The fiber optic measurement system allows for working pitches in the micrometer to centimeter range with high distance and time resolution. The radiation beam emitted from the optical fiber is reflected at the back side of the object being measured, particularly the substrate, and then received by a second optical fiber and converted into a voltage by a photoelectric converter. Different radiation flows are guided to the receiver, i.e., to the evaluation unit, by the pitch-related imaging of the radiation beam on the optical conductor on the receiver side. The variation process of the voltage-pitch characteristic curve is determined by the optical imaging characteristics and the photometric distance law. The optical imaging characteristics can be approximated by the intermediate beam. The beam originates at the center of the transmitting light conductor, strikes the object being measured at a certain angle between the light conductors, particularly on the back side of the substrate, and arrives at the receiving light conductor at the same angle through reflection. The intensity variation curve can be described by a sine function based on the incident angle. The path length of the light has an additional effect on the intensity. The intensity I decreases quadratically with the spacing a, where the spacing between the fiber element and the object being measured, particularly the first and / or second substrate, should be measured. For a more precise description of the model, the entire beam propagation process is included, except for the central beam. The light intensity on the object being measured can be simplified using the following equation:

[0035] I (object to be measured) = K' * sin (angle of incidence α) * 1 / a^2.

[0036] Angle α is the angle between the incident or reflected beam and the surface of the object being measured, particularly the back side of the substrate. The constant K' or K is a system constant that depends primarily on the characteristics of the optical fiber and the reflectivity of the object being measured.

[0037] Because the further propagation of light now occurs from the object being measured or its surface to the receiver, this equation must be applied again. The intensity applied at the receiver and evaluated in the evaluation unit qualitatively corresponds to the following variation curve:

[0038] I (receiver) = K * sin(incident angle α) * (1 / a^2) * (incident angle α) * (1 / a^2).

[0039] The spacing sensor can operate in two operating regions. In the rising region, the sensor has a higher sensitivity (slope) than in the falling region. A drawback of fiber optic spacing measurement is the need for a relatively large measurement area. This area can be reduced by decreasing the size of the optical fiber or fiber element. However, reduction means reducing the luminous flux within the optical fiber. Consequently, it is no longer possible to couple the input light energy sufficiently at the receiver to generate a sufficiently high signal. This problem is mitigated by using an entire fiber bundle instead of two optical fibers. One half of the fiber is used for coupling the light output, while the other half of the bundle is used for coupling the radiation input to the receiver. The distribution of the individual fibers can be random here.

[0040] The light source is located at the beginning of the signal path. The wavelength of the light must be matched to the optical fiber, the surface to be probed, especially the substrate and / or substrate holder, and the photoelectric converter used as an evaluation unit. The radiation source is preferably an LED. The LED can be driven by direct current. In alternative embodiments of the device, radiation feed with oscillating radiation or light can also be advantageously used. Here, the radiation constantly changes its intensity. The advantage of this type of modulation or locking is the elimination of interference from temperature drift and / or ambient brightness and feasible sources of error. The radiation source is coupled into the optical fiber in a suitable form. Typically, this is an integrated device (LED optical fiber). The radiation can be transmitted to the surface to be probed via a larger spacing. This is preferably in the bonding device according to the invention, because the heat source can therefore be located away from the substrate to be bonded.

[0041] A receiving optical fiber is directly disposed at the transmitting optical fiber. The incident and exit surfaces of the optical fiber are ground flat to avoid direct light transmission transverse to the fiber. Therefore, it is preferable to provide at least two fiber elements.

[0042] In particular, the sensor head, which houses the sensor element in the substrate holder, is secured to the optical fiber in an adjustable, especially angle-dependent, manner. Transmission via the optical fiber, i.e., the fiber element, can also be achieved at a greater spacing in the receiver component, making it advantageous to form a functionally integrated unit consisting of a radiation source and an evaluation unit.

[0043] The signal path used to measure the bonding wave during fusion bonding begins with a radiation source, preferably an LED. In this disclosure, light is specifically referred to as visible light, while electromagnetic radiation invisible to the human eye is referred to as radiation; however, those skilled in the art will understand that light and radiation are essentially interchangeable terms in this disclosure. If the LED is referred to as a radiation source below, it will be clear to those skilled in the art that other radiation sources may also be used. The light or the radiation from the LED is coupled into a fiber bundle, relayed, and particularly reaches the back surface of the substrate to be measured. From there, the emitted light is reflected, particularly at the back side of the substrate, and coupled into a receiving optical fiber. The optical fiber terminates at a photoelectronic evaluation unit and couples the light in there. The photoelectric converter can be, in particular, a phototransistor, a photodiode, or a secondary electron multiplier (SEv), which converts the optical signal into an electronic signal. Preferably, the resulting electrical signal current or signal voltage is then amplified by an operational amplifier. The resulting, particularly analog signal, can be connected to a data line after analog-to-digital conversion and, particularly with computer assistance, further processed and / or stored and / or displayed.

[0044] Preferably, the set spacing between the sensor element and the surface of the object has a value between 10 μm and 1000 μm, preferably between 10 μm and 500 μm, and particularly preferably between 10 μm and 200 μm. For example, the sensor element can be moved to a (coarse) spacing that falls within the corresponding value range in order to determine a spacing value with the highest possible resolution. The set spacing should be understood as the spacing used when the sensor element is oriented relative to the surface to be measured.

[0045] The desired value of the position to be approached, especially the orientation mark, is the ideal value. The motion device used to move the substrate holder approaches the ideal value. The defined environment around the ideal value can be understood as achieving the desired value. A coarse positioning device is understood as a positioning device in the case of a circumferential rotation drive (complete 360-degree rotation) whose approach accuracy and / or repeatability deviate from the desired value by more than 0.1%, preferably more than 0.05%, and particularly preferably more than 0.01% relative to the entire travel or rotation range.

[0046] For example, in a coarse positioning device with a travel distance of more than 600 mm (twice the substrate diameter), a mean approximation accuracy of 600 mm * 0.01%, or more than 60 micrometers, is generated as a residual uncertainty.

[0047] In other embodiments of coarse positioning, the residual uncertainty in the approximation accuracy or repeatability is less than 100 micrometers, preferably less than 50 micrometers, and particularly preferably less than 10 micrometers. Thermal interference should also be considered here. However, this is known to those skilled in the art.

[0048] A coarse positioning device can only complete a positioning task with sufficient accuracy if the deviation between the actual position and the expected position is within the range of motion of the associated precise positioning device.

[0049] Only when the deviation between the actual position and the expected position is within half the range of movement of the associated precise positioning device can the alternative coarse positioning device complete the positioning task with sufficient accuracy.

[0050] If the residual uncertainty of the approach accuracy and / or repeatability relative to the expected value is less than 500 ppb, preferably less than 100 ppb, and ideally less than 1 ppb, relative to the entire travel or rotation range, then the positioning device can be understood as a precision positioning device.

[0051] Preferably, the precision positioning device has an absolute positioning error of less than 5 micrometers, preferably less than 1 micrometer, particularly preferably less than 100 nm, very particularly preferably less than 10 nm, in the best case less than 5 nm, and in the ideal case less than 1 nm.

[0052] Preferably, at least one positioning device with high precision and reproducibility is provided. To improve the quality of substrate orientation relative to another substrate, the concept of mutual error correction can be used. Therefore, misalignment (rotation and / or movement) of the known substrate and its corresponding positioning device can be corrected by adjusting and correcting the position of the other substrate using correction values ​​or correction vectors to improve orientation accuracy. Here, the key to how open-loop or closed-loop control uses coarse and fine positioning, or only coarse and only fine positioning, for error correction lies in the magnitude and type of rotation and / or movement.

[0053] In a preferred embodiment of the device, the substrate can be deformed and / or temperature-controlled by means of mechanical adjustment elements and / or piezoelectric elements, i.e., deformation elements, to minimize misalignment during bonding. Targeted temperature variations alter the shape and size of at least one substrate. Targeted changes in the shape of the substrate holder alter the shape of the substrate fastened thereto.

[0054] Furthermore, positioning devices (coarse positioning devices, fine positioning devices, or combined positioning devices) and orientation mechanisms are considered synonymous. The orientation of the first substrate relative to the second substrate can preferably be performed in all six degrees of freedom: three translations according to coordinate directions x, y, and z, and three rotations about the coordinate directions. According to the invention, motion can be performed in any direction and orientation. Robots used for substrate handling and for substrate stacking handling are collectively referred to as motion devices. Fixing and holding components can be integrated into the motion device either as components or as functions.

[0055] Furthermore, the bonding equipment preferably includes a closed-loop control system and / or evaluation system, especially a computer, to perform the described steps, especially the motion process, stamping and separation, to perform corrections, and to analyze and store the operating status of the equipment according to the invention.

[0056] In particular, it is proposed that, for spatial resolution, a device consisting of multiple sensor elements is used, preferably more than 10 sensor elements, particularly more than 30 sensor elements, and particularly more than 50 sensor elements. This allows for the determination of the corresponding, especially locally resolved, orientation of at least one sub-region of the object or the entire object based on the distances recorded between the sensor elements and the object. Here, the sensor elements are preferably distributed in a predetermined pattern, such as a checkerboard pattern, or distributed on a circular track.

[0057] Particularly preferably, higher positional resolution can be achieved by increasing the number of sensor elements. Here, the sensor elements are preferably arranged in a two-dimensional configuration. Preferably, the sensor elements are arranged along an imaginary circular path, especially when bonding originates from the center of the substrate. Particularly preferably, the sensor surface elements are preferably constant in the radial direction. This ensures uniform positional resolution. Particularly preferably, adjacent sensor elements are arranged equidistantly from each other in at least one direction. The average spacing between adjacent sensor elements is preferably less than 5 cm, preferably less than 2.5 cm, and particularly preferably less than 1.5 cm. Here, the average is taken with respect to all spacings of adjacent sensor elements. In particular, the sensor elements are designed for signal reception and for outputting the received signal to an evaluation device. In the case of optical fibers, multiple fiber ends can be arranged side-by-side, and the fiber elements extend individually or in bundles to a common evaluation device spaced apart from the fiber ends oriented for signal reception.

[0058] Particularly preferred is that the object is either a first substrate or a second substrate. Determining the state of the second substrate precisely during bonding proves advantageous because the measurement allows for the detection of the propagation of the bonding wave and the deformation of the second substrate during bonding. This, for example, allows for real-time adjustment of the bonding. Preferably, the first substrate is inspected prior to bonding to ensure its correct orientation before bonding.

[0059] Preferably, for temporal resolution, multiple state determinations are measured during bonding to determine state changes detected over time, particularly for detecting the evolution of the bonding wave on the second substrate. This allows, for example, the detection of the bonding wave, particularly its temporal evolution, such as determining the bonding velocity. For this purpose, the movement of the back side of the second substrate during bonding is measured and determined. For this purpose, more than ten sensors are preferably used, particularly more than 30 sensors, and very particularly preferably more than 50 sensors, which are particularly evenly spaced and integrated on the substrate holder. Therefore, for spatial resolution, arrangements consisting of multiple sensor elements are particularly preferred, preferably more than 10 sensor elements, particularly preferably more than 30 sensor elements, and particularly preferably more than 50 sensor elements. These arrangements preferably cover a two-dimensional segment. Here, at least one fiber optic spacing sensor is preferably used to measure the bonding wave, wherein the fiber optic spacing sensor is statically and deterministically secured, and wherein adjustment of the fiber optic spacing sensor is performed without twisting the fibers and / or the fiber optic spacing sensor.

[0060] In particular, the spatial and positional propagation process of the bonding wave can be detected or determined from multiple measurements by sensors distributed on the substrate surface, enabling the influence of the bonding wave propagation process on closed-loop control. To this end, the detected bonding wave position data, along with anisotropy and / or anomalies, especially distortions or deformations, are compared with a computer-aided model of the ideal bonding wave propagation process. Errors observed during bonding, especially during molten bonding, are corrected promptly and, particularly in real-time, by means of closed-loop control, especially for individual vacuum zones (the timing and magnitude of pressure changes, especially the release of individual zones).

[0061] Here, radiation coupling input and evaluation are performed outside the substrate holder, preferably in a separate evaluation unit. In the substrate holder, preferably in the upper substrate holder itself, the end of the optical conductor is mounted such that the back side of the substrate is in the working area of ​​the sensor during the bonding method.

[0062] In one exemplary method, the time and location propagation process of the bonding wave during fusion bonding can be determined. Here, the spacing between the back side of the upper substrate and the upper substrate holder is obtained, stored, and visualized over time, and / or considered as a correction factor to correct for orientation errors. Here, the spacing and / or spacing changes are measured synchronously as a function of time, particularly using more than 50 sensors. In a particularly preferred embodiment of the device, 52 fiber optic spacing sensors can be distributed on the substrate holder to enable dense monitoring of the bonding wave.

[0063] Preferably, the orientation, such as position and / or orientation, of the second substrate is determined during and / or after it is accommodated in the substrate holder for state determination. For example, state determination is proposed to minimize the desired spacing between the first and second substrates prior to bonding. An exemplary method proposes measuring the local deviation and dispersion of the vertical spacing when the lower and upper substrates are oriented relative to each other, prior to bonding, particularly fusion bonding. The vertical spacing, also referred to as the bonding gap during orientation, is used to orient the substrates relative to each other with the smallest possible spacing without contact. Local variations in the vertical spacing may arise from manufacturing tolerances of the substrate holder, particularly the upper substrate holder. Local unevenness and / or shape deviations of the substrate holder can be inferred from a sequence of measurements of different substrates on the same substrate holder using a fiber optic spacing sensor, enabling the correction of the corresponding substrate holder.

[0064] Preferably, the bonding is influenced by state determination, particularly by open-loop or closed-loop control of the bonding wave velocity. In a preferred method, open-loop or preferably closed-loop control of the bonding wave shape can be achieved. During bonding of the upper substrate to the lower substrate, the fiber optic pitch sensor's pitch measurement is related to the manipulation of a separately switchable vacuum zone, particularly at the upper substrate holder, so that the bonding wave can travel as undistorted as possible within a plane, where asymmetry and / or anisotropy caused by the substrate can be compensated for to achieve optimal, undistorted bonding results. Measurements of bonding as overlay measurements at the fabricated substrate stack can be considered as additional corrections during the bonding process. Another advantage of using a fiber optic pitch sensor is the feasibility of precisely setting the working pitch using the invention's adjustment via fine-tuning elements such as gapless micrometers (which can in particular position the optical fiber without forcibly positioning it), allowing the use of sensors with higher precision but smaller measurement ranges. This reduces bonding errors because the smaller travel of the device increases orientation errors.

[0065] According to a preferred embodiment, the object is a component of a device for performing the method, such as a retaining element and / or a deforming element and / or a loading pin of the device.

[0066] In one exemplary method, the position, and particularly the parallelism, of the upper substrate holder relative to the lower substrate holder is determined. Surprisingly, it has been found that instead of setting the flatness based on measurements from three stabilizing pressure sensors or optical sensors, particularly those staggered by 120 degrees, the optimization process aims to achieve the most globally uniform parallel orientation of the upper substrate holder relative to the lower substrate holder using local spacing values, rather than setting the parallelism of the entire substrate holder surface relative to each other in an independent optimization process that may result in worse local distortion during bonding. For practical setting, fine adjustment elements, such as micrometers or, in particular, fine-threaded screws, can locally change the substrate holder surfaces relative to each other. In other words, the globally optimal value of parallelism across the entire surface of the substrate holder is calculated and set using the spacing of multiple locally measured values ​​between the substrate holders. As the parallelism of the substrate holder surfaces relative to each other improves, the bonding results between the individual bonding modules become better, leading to improved reproducibility and repeatability of the bonding process between devices with fiber optic spacing sensors.

[0067] Preferably, the state determination of the second substrate is used to determine the fixing and / or manipulating mechanism, by means of which the fixing and / or manipulating mechanism holds the first substrate and / or the second substrate and / or delivers it to the bonding.

[0068] Another approach proposes observing or determining the setting of the loading pins of the lower substrate holder. Finally, in a variation of the third application scheme, the parallelism of the loaded lower substrate relative to the upper substrate holder can be measured and correspondingly set using an optical fiber spacing sensor.

[0069] Another exemplary method proposes observing or determining the shape of the upper substrate or the second substrate during loading of the upper substrate holder. Conclusions regarding bonding characteristics, such as the expected warpage or sagging deformation of the upper substrate, can be derived from the shape of the upper substrate during loading, and consideration can be given during bonding, especially how much spacing must be set in the upper substrate before bonding, so that the upper and lower substrates do not undesirably contact each other during orientation, but rather achieve a small working pitch.

[0070] Another exemplary method proposes that the lower and / or upper substrates, i.e., the first and / or second substrates, are observed and detected while fastened to their respective substrate holders, particularly in such a way that deformation of the respective substrates can be detected temporally and positionally in relation to the applied vacuum. Therefore, the vacuum region can be manipulated not only in circuit sequence but also in the vacuum level used, so that the substrates can be bonded with as little distortion as possible. For this purpose, a particularly important aspect is that the substrates can be specifically deformed for bonding prior to bonding while fastened to the substrate holders, so that known distortion of the respective substrates can be compensated for and / or reduced. In other words, instead of forcibly considering the planar parallelism of the upper substrate relative to the lower substrate as the optimal initial position for successful and optimally oriented fusion bonding, the measured and correspondingly specifically deformed substrates are bonded together by means of fusion bonding, such that the resulting substrate stack has the smallest possible orientation error.

[0071] Another exemplary method proposes that adaptive substrate loading can be achieved by using measurements from a fiber optic spacing sensor in the upper substrate holder to actively control individually switchable, particularly isolated, vacuum sections of the upper and / or lower substrate holders, resulting in a substrate with the least possible distortion in the suction sequence and force. In another embodiment, the substrate can be intentionally deformed. This can be independently deduced by those skilled in the art from the applications described herein. Thus, the natural dispersion of substrate characteristics is compensated for by measuring the substrate when loading and securing it to the substrate holder.

[0072] Furthermore, all applications can be visualized automatically, especially with the help of computers, allowing process technicians or engineers to more quickly identify and eliminate potential sources of error.

[0073] Another aspect of the invention is an apparatus for bonding a first substrate to a second substrate, particularly by means of the method according to any one of the preceding claims, wherein the first substrate has a main segment and the second substrate has an auxiliary segment, wherein the apparatus is configured to form a bonding wave advancing along the bonding direction between the first and second sub-segments during bonding of the first and second substrates.

[0074] -- In the first sub-segment, the first substrate and the second substrate are connected, and

[0075] -- In the second sub-segment, the first substrate and the second substrate are still to be connected, wherein a sub-region of the second substrate in the second sub-segment is height-offset relative to a sub-region of the second substrate in the first sub-segment in a direction perpendicular to the main extension plane.

[0076] The device includes a sensor element, wherein, for determining the state of the object, the device is designed such that, before and / or during bonding, light is directed onto and reflected from the surface of the object, and the light reflected by the surface is measured by means of a sensor element used to determine the distance between the sensor element and the surface, and the distance between the sensor element and the surface is determined. All the advantages and characteristics described for this method can be similarly applied to this device.

[0077] In a first embodiment of the measuring device, an optical conductor is mounted on a sensor head. The sensor head includes not only optical fibers that guide radiation from a radiation source to the substrate, but also optical fibers for coupling outgoing measurement signals. The optical fibers are mounted in the sensor head in a manner that allows for independent adjustment of each other, without twisting, enabling precise setting of the corresponding working spacing and measurement range. For this purpose, in particular, elastic or spring-loaded backlash-free adjusting elements, such as pre-tightened micrometer screws, and especially backlash-free pre-tightened differential screw drives, can be used.

[0078] Because fiber optic spacing sensors have ground fiber ends and the manufacturing precision of the optical fiber and thus the sensor is limited, the present invention at least reduces, and preferably eliminates, the measurement uncertainty caused, particularly by the uncertain angular position of the optical fiber. This is because the optical fiber is mounted in the sensor head at a defined angular position, at least without twisting. Therefore, spacing and spacing variations can be detected with minimal uncertainty, allowing for precise detection and corresponding control of the bonding wave propagation process. For this purpose, the sensor can be integrated into a substrate holder, particularly by means of a gapless snap-fit ​​connection or a gapless bayonet connection.

[0079] Specifically, it is proposed that the sensor element has a fiber end and a signal transmission section, wherein the sensor element is designed such that the fiber end is configured for signal reception and the signal transmission section is configured for transmitting the signal to a spaced-apart evaluation device.

[0080] Particularly advantageously, in devices where the radiation source and evaluation unit are structurally separated from the sensor head, multiple sensors can be mounted in the substrate holder. By particularly adjusting and miniaturizing the entire sensor head, the number of sensor heads used in the device can be advantageously increased, enabling dense observation of bonded waves not only temporally but also spatially. Here, the radiation source and analysis unit are preferably placed away from the substrate holder.

[0081] The adjustment of the fiber optic spacing sensor installed in the substrate holder, especially the upper substrate holder, is performed using calibration and adjustment methods. For calibration, the following steps are performed, particularly those involving the following processes.

[0082] Preferably, the optical fiber element orientation is used for calibration. In a first method step, for example, an upper substrate is loaded and secured to an upper substrate holder. In a second method step, the fiber optic spacing sensors are iteratively set such that the respective sensors have at least one minimum spacing from the back side of the second substrate. In a third method step, the individual sensors are read and the intensity signals and / or spacings are stored. In a fourth method step, the stored intensity signals are set to zero spacing. In a fifth method step, the upper substrate is detached from the upper substrate holder and unloaded from the bonding space of the bonder. In a sixth method step, a lower substrate is loaded and secured to a lower substrate holder. In a seventh method step, the spacing from the fiber optic spacing sensor in the upper substrate holder—and thus from the upper substrate holder—to the bonding interface of the lower substrate on the lower substrate holder is measured. In an eighth method step, the upper substrate holder and / or the lower substrate holder is moved to another working spacing. In a ninth method step, particularly simultaneously with the eighth method step, not only the change in the spacing between the upper and lower substrate holders is detected, but also the spacing between the upper and lower substrate holders is detected. In the tenth method step, the actual spacing is compared with the expected value of the spacing variation of the upper and lower substrate holders, and the differences are recorded separately in relation to the sensors to record specific calibration values ​​and intensity curves for the fiber optic spacing sensors. In the eleventh method step, calibration iteratively performed using replacement substrates is recorded as a measurement sequence to establish calibration values ​​for the fiber optic spacing sensors as a knowledge store and / or database. The intensity curve refers to a pair of points that approximate the intensity value for a given spacing. In particular, the intensity curve can be approximated using empirical mathematical formulas so that the expected intensity can be interpolated for a given spacing of the substrate holders in the bonding device. Conversely, the spacing is determined from the measured intensity in each sensor.

[0083] Replacing the substrate for calibration means performing a statistically relevant number of measurements with different substrates: in particular, variations in substrate thickness, reflectivity in the material, and material differences or variations due to different positioning on the substrate holder can be detected and used as correction values ​​for the measurement of the bonding wave, thus affecting the bonding wave. Therefore, facility- and substrate-specific correction values ​​are determined.

[0084] Therefore, during fusion bonding, all feasible spacings between the upper and lower substrate holders can be better detected in space and time within the operating range of the fiber optic spacing sensor.

[0085] In particular, the bonding process is influenced by state determination, especially by open-loop control of the bonding wave velocity. To this end, deforming elements and / or fixing elements are manipulated in a targeted manner, and sub-regions of the second substrate are released or retained.

[0086] Preferably, to determine the influence of state on the bonding process, machine learning algorithms and / or empirical values ​​stored in a database are employed. To utilize the measured state determinations obtained across multiple bonding processes, the detected state determinations, along with the results of the bonding processes, can be provided as a test set to a neural network. Based on the test set, the neural network develops a novel strategy for open-loop control of the bonding process in determined state determinations and preferably applies it to subsequent bonding processes in similar state determinations. Thus, this method can be used to further optimize the bonding process.

[0087] Preferably, the sensor element has at least one optical fiber element and preferably includes an optical fiber spacing sensor. Particularly preferably, at least one optical fiber element is movably, and in particular pivotally, integrated into the device.

[0088] Devices for bonding substrates include, in particular, the following functional components and / or modules:

[0089] - Substrate Reception: A substrate holder is used for the substrate reception. For this purpose, at least one substrate holder equipped with sensors and actuators is particularly used. An improved device is understood as another, particularly independent invention, having a substrate holder for influencing the bonding wave, having at least one, preferably more than 30, sensors and 30 actuators. In a particularly preferred embodiment of this device, the substrate holder has more than 50 sensors and 50 actuators.

[0090] Preferably, the bonding apparatus includes at least one fiber optic spacing sensor as a sensor, and preferably the same number of fiber optic spacing sensors as the vacuum region can be switched independently. In particular, the fiber optic spacing sensor can be tunably integrated into the substrate holder, especially into the upper substrate holder.

[0091] Here, the substrate holder has individually switchable, fluidly isolated regions, particularly vacuum regions, each associated with a fiber optic pitch sensor, and in particular, the fiber optic pitch sensor is integrated into the corresponding vacuum region, so that the measurement of substrate fastness and vacuum adjustment are connected to each other in the shortest closed-loop control loop, and wherein the deformation of the substrate is measured at the location where the action of the vacuum region causes the substrate to deform.

[0092] The substrate holder has a fixing device. The fixing device is used to fix the substrate. The fixing device can be...

[0093] 1. Mechanical fixing devices, especially

[0094] 1.1. Fixture

[0095] 2. Vacuum fixing device, especially with

[0096] 2.1. Individually operable vacuum track

[0097] 2.2. Interconnected vacuum orbits

[0098] 3. Electrical fixing devices, especially

[0099] 3.1. Static electricity fixing device

[0100] 4. Magnetic fixing device

[0101] 5. Adhesive fixing devices, especially

[0102] 6. Gel bag fixing device

[0103] 7. Fixtures with adhesive, especially maneuverable, surfaces.

[0104] The fixing device is particularly capable of electronic control. A vacuum fixing device is the preferred method. The vacuum fixing device preferably comprises multiple vacuum tracks extending from the surface of the substrate holder. The vacuum tracks are preferably individually operable. In applications where this is more technically feasible, some vacuum tracks can be combined into vacuum track segments, which can be individually operable and thus evacuated or filled. However, each vacuum segment is independent of the others. This allows for the feasibility of constructing individually operable vacuum segments. The vacuum segments are preferably constructed in a ring shape. However, any shape is conceivable as a vacuum zone. This enables targeted fixing and / or detachment of the substrate from the substrate holder.

[0105] The device with fiber optic spacing sensor according to the present invention can also be used in the following feasible applications, which are particularly considered as independent inventions:

[0106] - A motion and / or orientation mechanism for a substrate, the motion and / or orientation mechanism having an adjustment element and an actuator for generating a force to change the curvature of the substrate.

[0107] In one embodiment of the device, a motion mechanism for accommodating the substrate allows the substrate to be repeatedly deformed.

[0108] - Mechanisms for the movement and / or orientation of substrates, such as coarse drive mechanisms and / or fine drive mechanisms.

[0109] - Bond initiation mechanisms for fusion bonding, particularly pins, fluid pressure media, nozzles with gas overpressure, and / or combinations thereof.

[0110] - In the device according to the invention, the motion and / or orientation mechanism is preferably understood as a motion device having a drive system, a guide system, a retaining element and a measuring system, so as to move, position and orient the optical system and / or the substrate relative to each other.

[0111] The motion device can produce any motion because it moves independently, which allows the motion device to preferably include both rapid coarse positioning equipment that does not correspond to accuracy requirements and fine positioning equipment that works precisely.

[0112] A key advantage is the availability of fiber optic spacing sensors as measurement mechanisms in bonding equipment: optical fibers enable compact configurations, allowing for the integration of high-density measurement mechanisms within the substrate holder. Furthermore, retrofitting the bonding equipment is feasible because the evaluation and radiation sources do not need to be placed directly on the substrate and / or substrate holder. Another advantage is the significantly higher achievable data density compared to conventional measurement methods such as laser sensors or confocal sensors.

[0113] Furthermore, the equipment according to an advantageous embodiment may include a supply system as well as auxiliary and / or replenishment systems (compressed air, vacuum, electrical energy, liquids such as hydraulic fluid, coolant, heating medium, mechanisms and / or devices for temperature stabilization, electromagnetic shielding, ionizers and / or deionizers, electrostatic dust collectors).

[0114] Furthermore, the device according to the invention includes supports, baffles, and active or passive subsystems for vibration suppression, vibration attenuation, or vibration elimination. Parts made of natural hard rock or mineral castings or ductile iron castings or hydraulic concrete can be understood as supports, and these parts are particularly mounted in a vibration-attenuating and / or vibration-isolated and / or vibration-eliminating manner.

[0115] Furthermore, the device according to the invention includes at least one measuring system, which preferably has a measuring unit for each axis of motion, particularly a displacement measuring system and / or an angle measuring system. Additionally, the device includes at least one measuring system, preferably having a measuring unit for radiation intensity, particularly for radiation of hardened imprinted materials.

[0116] In addition, the device includes at least one measurement system for observing and / or inspecting adjustment or orientation marks on the first and second substrates.

[0117] In addition, the device includes at least one measurement and closed-loop control system for pressure, particularly vacuum and / or overpressure, which measures, detects and controls the pressure on / in the substrate during bonding.

[0118] Furthermore, the device according to the invention includes at least one measurement system for observing the orientation of substrates relative to each other. The substrates are, for example, additionally configured to determine the spacing via back-reflected light.

[0119] Not only tactile, i.e., touch-based or non-tactile measurement methods can be used. The measurement reference, the unit of measurement, can exist as a physical entity, especially as a scale, or it can exist implicitly in the measurement method, such as the wavelength of the radiation used.

[0120] To achieve orientation accuracy prior to bonding, at least one measurement system can be selected and used. The measurement system employs a measurement method. Specifically, the measurement method can utilize...

[0121] • Sensing methods, and / or

[0122] • Capacitive method, and / or

[0123] • Resistive method, and / or

[0124] • Comparison methods, especially optical image recognition methods, for detecting location markers and / or QR codes, and / or

[0125] • Incremental or absolute methods (especially using a glass reference as a scale, or an interferometer, especially a laser interferometer, or using a magnetic reference), and / or

[0126] • Runtime measurement (Doppler method, time-of-flight method) or other time detection methods, and / or

[0127] • Triangulation methods, especially laser triangulation.

[0128] • Autofocus method, and / or

[0129] • Intensity measurement methods, such as fiber optic distance meters.

[0130] For example, measurements can be combined and / or referenced and / or correlated with each other, such that the positions of other associated orientation marks can be inferred by measuring the orientation mark. In particular, the position of the substrate can be calculated and corrected accordingly from the position values ​​of the substrate holder and the detected orientation marks.

[0131] In a first embodiment of the invention, for position determination, particularly 3D position determination at one, two, three, or any number of points, optical pattern recognition using a camera system can utilize a unique reference for position and height. The pattern is detected continuously, especially in a real-time system, during substrate orientation. The listed measurement methods can also be used for position determination.

[0132] Preferably, the motion device not used for fine adjustment is configured as a robotic system, preferably a robotic system with incremental displacement sensors. The accuracy of the motion device used for assisting motion is decoupled from the accuracy used for substrate orientation. This allows the assisting motion to be performed with low repeatability accuracy of less than 1 mm, preferably less than 500 micrometers, and particularly preferably less than 150 micrometers.

[0133] The accuracy of the motion device used for orientation is preferably less than 200 nm, preferably less than 100 nm, particularly preferably less than 50 nm, very particularly preferably less than 20 nm, optimally less than 10 nm, and ideally less than 1 nm.

[0134] In a particularly preferred embodiment of the device, the orientation accuracy error is 20% of the maximum permissible orientation error, particularly preferably 10% of the maximum permissible orientation error, and in the optimal case, 1%.

[0135] The method is preferably created as a formulation and implemented in a machine-readable form. A formulation is an optimized set of values ​​for parameters related to a function or method technique. Using a formulation allows for ensuring the reproducibility of the production process.

[0136] In one embodiment of the bonding method, the lower substrate and the upper substrate are fused together via the following process, particularly the following steps:

[0137] In the first method step, the lower substrate is placed on the lower substrate holder and the distance between the optical fibers is measured using at least one optical fiber spacing sensor mounted in the upper substrate holder.

[0138] In the second method step, the lower substrate is secured to the lower substrate holder using a vacuum zone, and the securing is measured by means of at least one fiber optic pitch sensor as an additional closed-loop control, so that local deformation of the lower substrate is preferably minimized.

[0139] In the third method step, the upper substrate is loaded into the bonding apparatus and measured in a free form by means of at least one fiber optic spacing sensor so that deformation and / or critical twist of the upper substrate can be detected and, in particular, corrected.

[0140] In the fourth method step, the upper substrate is secured to the upper substrate holder, particularly by means of a vacuum zone, and measurements are taken using at least one fiber optic spacing sensor. Through the adjusted securing of the upper substrate, undesirable twisting and / or deformation of the upper substrate can be minimized, and preferably eliminated.

[0141] In the fifth method step, the substrates are oriented relative to each other, specifically according to the orientation marks.

[0142] In the sixth step of the method, fusion bonding is initiated by contacting the upper substrate and the upper substrate. Here, fusion bonding can be initiated using bonding pins, in particular. The start of the bonding wave process can be observed using at least one fiber optic spacing sensor to allow the bonding wave to pass through in a controlled manner.

[0143] In the seventh method step, the propagation process of the bonding wave is observed by means of at least one fiber optic sensor in the upper substrate holder. Here, the distance between the back side of the upper substrate and the upper substrate holder is recorded and / or stored and / or transmitted to the closed-loop control device of the bonding wave, especially the vacuum zone closed-loop control device, and / or visualized and / or processed and / or statistically evaluated as a function of time.

[0144] In the eighth method step, the propagation process of the bonding wave, in particular relative to the seventh method step, influences at least one vacuum region of the substrate holder in real time by means of the effect of vacuum, so as to minimize the distortion during bonding.

[0145] In the ninth method step, the fusion bonding of the substrate stack is terminated and the upper substrate holder is separated from the upper substrate. This method step may optionally be performed using the seventh and / or eighth method steps.

[0146] In the tenth method step, the bonded substrate stack is removed from the bonding equipment in pre-bonding and, in particular, conveyed to a quality control device.

[0147] Where a device feature is disclosed in the present and / or subsequent description of the accompanying drawings, that device feature shall also be deemed to be disclosed as a method feature, and vice versa. All numerical values ​​and relational descriptions (parallelism, coincidence, perpendicularity, flatness, etc.) in this disclosure are used as the concept of “tolerance-tolerant quantities”, making them particularly applicable to tolerances of untoleranced length and angular dimensions according to ISO 2768 and semiconductor industry-related semiconductor standards (for flatness, waviness, deflection, particle load, etc.), unless tolerances are explicitly stated.

[0148] Another subject of the invention is a substrate holder for a device according to the invention, wherein a sensor element is integrated into the substrate holder. All the advantages and features described for the device can be similarly applied to the substrate holder, and vice versa.

[0149] Another subject of the invention is a sensor element for integration into a device according to the invention or a substrate holder according to the invention. All the advantages and characteristics described for the device can be similarly applied to the substrate holder and the sensor element, and vice versa. In particular, it is proposed that existing devices can be modified using the sensor element. For example, the sensor element is sized such that it can be inserted into a recess, which is initially configured or is a vacuum opening or opening for deformable elements. Thus, it is only necessary to place and secure the sensor element into the corresponding recess. Attached Figure Description

[0150] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the accompanying drawings. The drawings show:

[0151] Figure 1 This is a schematic diagram of a fusion bonding device with an integrated fiber optic spacing sensor.

[0152] Figure 2 This is a partial schematic diagram of a substrate holder with an integrated fiber optic sensor. Detailed Implementation

[0153] In the accompanying drawings, the advantages and features of the invention are indicated by reference numerals that are respectively identified according to embodiments of the invention, wherein components or features having the same or the same function are indicated by the same reference numerals.

[0154] The accompanying drawings should be understood as sketches from which size relationships or proportions cannot be derived. The drawings may show the relationships of parts relative to each other in exaggerated, illustrative terms.

[0155] Figure 1 A portion of the apparatus 1 for fusion bonding is shown. The bonding apparatus 1 includes a support 8 on which an optical inspection mechanism 3 for the lower substrate 11 can be secured to a movable support 2 by means of a motion device 4. Specifically, an optical inspection mechanism 7 for detecting orientation marks (not shown) on the upper substrate is located on the same optical axis as the optical inspection mechanism 3. The movable support 5 and the motion device 6 enable the optical inspection mechanism 7 to be focused onto the orientation marks.

[0156] The lower substrate holder 9 can accommodate the lower substrate 11. The vacuum section and vacuum channel of the substrate holder 9 are not shown. The substrate movement required for loading, unloading, and adjustment can be performed by means of the motion device of the lower substrate holder 10.

[0157] The upper substrate holder 12 can accommodate an upper substrate (not shown). The vacuum section and vacuum channel of the upper substrate holder 12 are not shown. Loading and unloading, as well as the necessary substrate movement, can be performed by means of a moving device using the upper substrate holder 13. A bonding pin 14 is schematically shown, which initiates the melting and bonding of the bonding wave upon approach to the substrate. An optical fiber spacing sensor 15 is shown, having two hypothetical overlapping beams 16, by means of which the spacing a between the upper substrate holder 12 and the substrate 11, or between the upper substrate holder 12 and the lower substrate holder 9, or between the upper substrate holder 12 and the upper substrate can be measured, in particular. Further optical fiber spacing sensors, radiation sources, and evaluation units are not shown. Those skilled in the art will understand, in particular, that a sensor element configured as a fiber has components at its fiber ends for receiving light or signals. The signals are then forwarded to a common evaluation device, which is spaced apart from the sensor element as a relatively large component. Preferably, signals from multiple fibers with side-by-side fiber ends travel together so that they can be evaluated together in the common evaluation device.

[0158] Figure 2 A partial top view of the upper substrate holder 12' is shown, schematically illustrating the functional surfaces. Here, the two optical fibers of the fiber optic spacing sensor are shown as 15'. The vacuum nozzle 17 is fluidly connected to a vacuum control device, allowing adjustment of the applied vacuum. The sealing lip 18 schematically defines the vacuum region. Another similar vacuum region with the same components is shown without markings.

[0159] List of reference numerals in the attached diagram:

[0160] 1. Equipment for bonding substrates

[0161] 2. Movable support for the upper optical inspection mechanism

[0162] 3. Optical testing institutions

[0163] 4. Moving equipment of the optical inspection mechanism

[0164] 5. Movable support for the lower optical inspection mechanism

[0165] 6. Moving equipment of the lower optical inspection mechanism

[0166] 7. Optical Inspection Agency

[0167] 8 brackets

[0168] 9. Substrate Holder

[0169] 10. Motion device for the lower substrate holder

[0170] 11. Lower substrate

[0171] 12, 12' Upper substrate holder

[0172] 13. Movement device for the upper substrate holder

[0173] 14-key combination pin

[0174] 15, 15' fiber

[0175] 16. Symbolic Measurement of Radiation by Fiber Optic Spacing Sensors

[0176] 17 Vacuum Nozzle

[0177] 18 Vacuum seals, sealing lips

Claims

1. Method for bonding a first substrate with a second substrate (10), wherein the first substrate has a main section and the second substrate (10) has a secondary section, wherein, when bonding the first substrate with the second substrate (10), a bonding wave is formed between a first subsection and a second subsection, which proceeds along a bonding direction, - in the first subsection, the first substrate and the second substrate (10) are connected, and - in the second subsection, the first substrate and the second substrate (10) are yet to be connected, wherein a subregion of the second substrate (10) in the second subsection is preferably at least temporarily highly offset in the bonding in a direction extending perpendicular to a main extension plane with respect to a subregion of the second substrate (10) in the first subsection, wherein, prior to and / or during the bonding, for a state determination of an object, light is directed onto a surface of the object and reflected, and the light reflected by the surface is measured by means of a sensor element (15) for determining a distance between the sensor element (15) and the surface, and the distance (a) between the sensor element (15) and the surface is determined.

2. Method according to claim 1, wherein at least one optical fiber element is used as a component of the sensor element (15), and wherein preferably a fiber distance sensor is used as sensor element (15).

3. Method according to any of the preceding claims, wherein a set distance between the sensor element (15) and the surface of the object has a value of between 10 pm and 1000 pm, preferably between 10 pm and 500 pm and particularly preferably between 10 pm and 200 pm.

4. Method according to any of the preceding claims, wherein for the spatial resolution a device consisting of a plurality of sensor elements (15) is used, preferably a device consisting of more than ten sensor elements (15), particularly preferably more than 30 sensor elements and particularly preferably more than 50 sensor elements (15), and / or at least one sensor element (15) is moved.

5. Method according to any of the preceding claims, wherein the object is the first substrate or the second substrate (10).

6. Method according to claim 5, wherein a plurality of state determinations are detected during the bonding for determining a change in the state detected over time, in particular for detecting a bonding wave evolution at the second substrate (10).

7. Method according to any of the preceding claims, wherein the bonding is influenced in accordance with the state determination, in particular an open-loop control of the bonding wave speed.

8. Method according to any of the preceding claims, wherein the state determination is used to minimize a distance to be set between the first substrate and the second substrate (10) prior to the bonding.

9. The method according to any one of claims 5 to 8, wherein the orientation of the second substrate and / or the first substrate is determined for a status determination during and / or after the second substrate (10) and / or the first substrate is accommodated in the associated substrate holder (10, 12).

10. The method according to any one of the preceding claims, wherein the object is a component of a device (1) for carrying out the method, such as a substrate holder (9, 12) and / or a deformation element of the device (1).

11. A device (1) for bonding a first substrate with a second substrate (10), in particular by means of a method according to any one of the preceding claims, wherein the first substrate has a main section and the second substrate (10) has an auxiliary section, wherein the device is configured for, when bonding the first substrate with the second substrate (10), forming a bond wave advancing along a bond direction between a first subsection and a second subsection, - in the first subsection, the first substrate and the second substrate (10) are connected, and - in the second subsection, the first substrate and the second substrate are yet to be connected, in particular for detecting a bond wave evolution of the second substrate (10), wherein a subregion of the second substrate (10) in the second subsection is highly offset in a direction extending perpendicular to a main extension plane relative to a subregion of the second substrate (10) in the first subsection, wherein the device comprises a sensor element (15), wherein, for a status determination of an object, the device is designed such that, before and / or during the bonding, for a status determination of an object, light is directed onto a surface of the object and is reflected, and the light reflected by the surface is measured by means of a sensor element (15) for determining a distance between the sensor element and the surface, and the distance (a) between the sensor element (15) and the surface is determined.

12. The device (1) according to any one of the preceding claims, wherein the sensor element (15) has at least one optical fiber element and preferably comprises a fiber distance sensor, wherein preferably for a spatial resolution, a device consisting of a plurality of sensor elements (15) is used, preferably a device consisting of more than ten sensor elements (15), particularly preferably more than 30 sensor elements and particularly preferably more than 50 sensor elements (15), and / or at least one sensor element (15).

13. The device (1) according to claim 12, wherein the sensor element (15) has a fiber end and a signal transmission section, wherein the sensor element (15) is designed such that the fiber end is provided for signal reception and the signal transmission section is provided for transmitting a signal to a spaced-apart evaluation device.

14. A substrate holder (12) for a device according to any one of claims 10 to 13, wherein the sensor element (15), in particular the fiber end of the sensor element, is integrated into the substrate holder (12).

15. A sensor element (15) for integration into a device (1) according to any one of claims 1 to 13 or a substrate holder (12) according to claim 14.

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