Wafer Conditioning

Abstract

The present invention relates to a method for conditioning bonding of substrates, the method comprising applying a plurality of localized modifications within a first substrate to facilitate bonding of the first substrate to a second substrate. The present invention further includes a conditioning method, a corresponding computer program, and a corresponding apparatus.

Description

[Technical Field]

[0001] The present invention relates to conditioning substrates. In particular, the present invention relates to a method for conditioning bonded substrates, a method for conditioning bonded substrates, a method for bonding substrates, and corresponding apparatus and computer programs. [Background technology]

[0002] In the field of semiconductor technology, various methods and apparatuses are known for processing a substrate. For example, the substrate may include a (semiconductor-based) substrate in the form of a wafer, the processing of which may enable the fabrication of one or more chips. Typically, such fabrication of chips may require a complex integration of multiple processing steps applied to the substrate. For example, the processing steps may include material deposition on the substrate, etching of the substrate, oxidation of the substrate, lithographic patterning on the substrate, etc. For example, the processing steps may also include bonding the substrate to another substrate (e.g., wafer-to-wafer bonding, wafer-to-die bonding, where the other substrate may be a wafer or a die / chip).

[0003] The processing of a substrate may typically be engineered to produce a specified result on the substrate (e.g., a specified material deposition height, a specified etch depth, a specified lithography overlay, etc.). However, the processing of a substrate may also lead to the induction of undesirable characteristics on the substrate. The undesirable characteristics may, in turn, adversely affect further processing of the substrate. In particular, the undesirable characteristics may already be present in the substrate without being induced by the particular processing (e.g., the unprocessed semiconductor substrate of a wafer may already possess the undesirable characteristics). In some cases, the root cause of the undesirable characteristics may even be unknown.

[0004] In this regard, many types of undesirable characteristics of the substrate are possible. For example, undesirable characteristics may include undesirable mechanical properties of the substrate. This may include undesirable bending of the substrate, undesirable shape of the substrate, and / or undesirable mechanical stress present in the substrate, etc. Other types of undesirable characteristics may include, for example, undesirable defects and / or undesirable surface characteristics of the substrate (e.g., undesirable surface roughness, undesirable discoloration, undesirable surface energy, undesirable warping, etc., including, for example, structured patterns on the substrate).

[0005] Therefore, it may be necessary to condition the substrate via a conditioning step to minimize or substantially eliminate the effects of undesirable properties of the substrate, which conditioning may be optimized to enable a defined processing of the substrate and / or may even be highly relevant to enable a defined processing of the substrate.

[0006] In this regard, various types of conditioning of substrates are known in the semiconductor arts.

[0007] For example, conditioning the substrate may include cleaning the substrate (e.g., chemical cleaning and / or plasma treatment) and / or applying a thermal treatment to the substrate to condition the substrate. It is also known to apply a chemical mechanical polishing (CMP) process to the substrate to condition the substrate for further processing.

[0008] However, currently known techniques for conditioning substrates are not always optimal, and therefore there is a need to find ways to improve substrate conditioning. Summary of the Invention

[0009] The aspects described herein address, at least in part, the above needs.

[0010] A first aspect relates to a method for conditioning the bonding of substrates, comprising applying a plurality of localized modifications within a first substrate to facilitate bonding the first substrate to a second substrate.

[0011] The inventive concept includes the idea that conditioning of a substrate is performed by defined local modifications within the substrate, and thus defined processing interactions within the substrate may occur as conditioning takes into account further processing of the substrate (e.g., taking into account bonding of the substrate to another substrate).

[0012] This may be considered in contrast to conventional conditioning processes for substrates, in which substrate modifications may be applied to the (external) surface of the substrate. In this regard, conventional conditioning processes may involve defined physical and / or chemical interactions with the surface of the substrate. However, such general approaches may not apply modifications within the substrate in a defined manner. For example, a typical conditioning step for substrates in the semiconductor industry may include chemical wet cleaning, plasma treatment, and / or chemical mechanical polishing (CMP) of the substrate. Such general conditioning methods may be based solely on defined chemical and / or physical interactions with the surface of the substrate. For example, the interaction with the surface of the substrate may include a liquid disposed across the surface (e.g., in the case of wet cleaning conditioning), a plasma cloud interacting with the surface (e.g., in the case of plasma treatment conditioning), and / or a mechanical force being applied on the surface of the substrate (e.g., in the case of a CMP process).

[0013] Furthermore, in some cases, typical conditioning techniques may apply a global modification to a substrate. For example, typical conditioning processes such as chemical wet cleaning, plasma treatment, CMP processes, and / or thermal treatments may be considered to apply a global modification to a substrate. That is, in these typical conditioning techniques, the defined physical and / or chemical interaction of the conditioning may occur only globally with respect to the entire substrate (e.g., the entire substrate surface). For example, the global interaction may include treating the entire surface of the substrate in a substantially homogeneous manner for conditioning (e.g., as in the case of wet cleaning, plasma treatment, and CMP processes described above). The global interaction may also include thermal treatment, including heating or cooling the entire substrate in a substantially homogeneous manner for conditioning the substrate (e.g., in a furnace or cryogenic chamber). Thus, in such typical conditioning processes, the defined physical and / or chemical interaction may not be local, and thus it may not be possible to apply multiple local modifications to the substrate in a defined manner, let alone in a defined manner.

[0014] General techniques for conditioning substrates may not always lead to optimal results. For example, general techniques may have limited conditioning effectiveness and may not always be able to reduce or substantially eliminate undesirable characteristics of the substrate in a defined manner. Furthermore, general conditioning techniques may not always be appropriate and / or customizable given the (specific) characteristics of a particular process and / or substrate.

[0015] To illustrate one example, typical conditioning techniques may have limited conditioning effects because interactions may occur only with the surface of the substrate. For example, wet cleaning and / or plasma treatment conditioning may therefore be limited to surface effects such as reducing surface defects, surface etching, and / or altering the surface energy of the substrate.

[0016] Common conditioning techniques for the surface of a substrate can also be limited because they only result in global conditioning. In the case of global conditioning, the conditioning results can be limited, not easily controllable, and / or not easily predictable. To illustrate one example, a thermal treatment for substrate conditioning can involve heating the entire substrate by applying heat to the surface of the substrate. However, because typically only global, quantitative substrate trends can be associated with the thermal treatment, the conditioning results may not be easily predicted. For example, it may only be known quantitatively that the thermal treatment can induce an increase or decrease in mechanical stress in the substrate (while accurate, quantitative conditioning results, e.g., substrate topography, may not necessarily be derived).

[0017] In particular, the inventors have found that applying multiple local modifications within a substrate can mitigate the shortcomings of common conditioning approaches: applying local modifications within a substrate can allow for a high degree of freedom in conditioning the substrate, while also expanding the field of possible conditioning effects.

[0018] For example, each local modification of multiple local modifications within a substrate may be individually adjustable, such that highly customized and / or flexible conditioning may occur. This may significantly increase the possibilities for conditioning a substrate that may not be possible, for example, through general conditioning, which may only globally alter the substrate. Furthermore, applying multiple modifications within a substrate may produce one or more adaptable conditioning effects (e.g., from within the substrate) that may not be possible with general conditioning approaches, which may be based on interactions with the surface of the substrate (as described herein).

[0019] Applying multiple local modifications within a substrate may therefore enable an improved mechanism for substantially eliminating one or more undesirable characteristics of the substrate. The present invention may therefore enable conditioning of a substrate in a highly targeted manner, for example to facilitate specific processing of the substrate.

[0020] In particular, the present inventors have found that the inventive conditioning of a first substrate can be highly suitable, for example, for facilitating bonding of the first substrate to a second substrate. Because bonding of two or more substrates typically involves a highly complex bonding process, undesirable characteristics of the substrates (e.g., undesirable mechanical properties and / or undesirable surface properties) can lead to poor bonding quality (e.g., adversely affecting at least one bonding parameter) or even to a complete failure of the bonding process. Typically, general substrate conditioning techniques for bonding may not always be sufficient to condition the substrates for the complex aspects of the bonding process, since the general conditioning step may rely only on overall modification and / or modification of the surface of the substrates.

[0021] However, by applying multiple modifications in the first substrate according to the present invention, a high degree of conditioning freedom may be possible such that the first substrate may be conditioned in a highly defined manner to facilitate even complex bonding processes of the first substrate to a second substrate.

[0022] In particular, the inventor's insight that multiple modifications may be applied within a substrate to condition the substrate for bonding was hindered by prior knowledge. That is, in the semiconductor technology field, multiple local modifications within a substrate are typically associated with crystallographic defects that can have one or more adverse effects on the physical properties of the substrate (e.g., higher mechanical stress resulting in surface defects, uneven crystal quality, etc.). However, during bonding, the substrate may need to withstand high physical and / or mechanical stresses. Therefore, local modifications within a substrate (e.g., defects within a substrate) are typically considered detrimental to bonding of the substrate to another substrate. Thus, it is very common to actively minimize or eliminate local modifications within a substrate, for example, to facilitate certain processing of the substrate (e.g., bonding of the substrate). For example, crystal growth or epitaxial processes for producing substrates are typically engineered to actively minimize crystalline defects within the substrate to facilitate certain (subsequent) processing of the substrate. However, the inventors have discovered that actively applying predetermined local modifications within a substrate (e.g., in a predetermined manner) (as described herein) can facilitate bonding of the substrate to another substrate.

[0023] A local modification within a substrate (in accordance with the present invention) may include a defined local deviation (e.g., a defined local perturbation) within the substrate that did not exist prior to the application of the multiple local modifications. In particular, a defined local modification may be thought of as a (spatially separated) pixel applied within the substrate. For example, the pixel may be spatially separated within a local region and / or a local volume within the substrate.

[0024] In one example, the local deviations may include defined local mechanical deviations. For example, the defined local mechanical deviations may include local density variations. The local mechanical deviations may include, for example, (spatially separated) pixels having a different density than the surrounding material of the substrate.

[0025] In one example, the defined local mechanical deviation may include a local stress element that can induce a local stress in the substrate. The local stress element may include an element that can induce a strain (e.g., a predefined strain) along one or more axes of the substrate. For example, the local stress element may be adapted to induce a predetermined first force along a first axis in the substrate and a predetermined second force along a second axis in the substrate. For example, the magnitude of the first force may be different from the magnitude of the second force. It may also be considered that the magnitude of the first force substantially corresponds to the magnitude of the second force. In one example, the first axis may be orthogonal to the second axis. In another example, the first axis and the second axis may subtend an angle other than 90°. In one example, the variation in local pixel density may include an elliptical shape (e.g., oval) and / or a circular shape (e.g., spherical). In one example, the local stress element may include alignment (e.g., pixel alignment). The alignment may include an orientation of a first force vector (and / or a second force vector) of a local stress element relative to a reference orientation. For example, the pixel alignment (e.g., force vector) may be tilted at a certain angle relative to the reference orientation. In one example, the alignment may include an orientation of a characteristic axis of a pixel's local density variation (e.g., an orientation of a major axis of the local density variation, e.g., an ellipse axis if the local deformation includes an elliptical shape). In one example, the local stress element may include (or may be referred to as) a microstrain element.

[0026] In one example, the local modification (as described herein) may be a persistent local modification. Thus, the local modification may persist for an extended period of time. In particular, the degree of persistent local modification may change over time. For example, the degree of strain and / or the magnitude of (mechanical) force induced in the substrate via the local modification may decrease over time. However, the local modification may persist to such an extent that the presence of persistent local modification in the substrate may be verified over an extended period of time (e.g., after 1 day, 1 week, 1 month, 1 year, 10 years, 20 years, etc.).

[0027] In particular, a local modification (as described herein) may induce a local optical deviation. The local optical deviation may include a deviation in the refractive index and / or absorption coefficient within an effective optical region around and / or within the local modification. For example, the presence of a local modification may thus be verified via optical analysis of the substrate (e.g., via optical measurements, e.g., a microscope).

[0028] In particular, in typical approaches, the conditioning of a substrate may not last for an extended period of time (e.g., only for a period of a few hours or days). Therefore, typical approaches may require further processing of the substrate within a reasonable time window after conditioning. This may require complex time-coupling management (e.g., in a semiconductor fab) for processing the substrate. However, the present inventors have discovered that by applying a persistent modification locally within the substrate, such drawbacks may be mitigated, as the conditioning effect may last for an extended period of time.

[0029] In one example, applying a plurality of local modifications to the first substrate may include generating a defined arrangement (e.g., an array, a matrix) of the plurality of local modifications within the first substrate. The defined arrangement may be defined via one or more arrangement parameters, which may be adaptable to allow for customizable / flexible conditioning with greater degrees of freedom compared to common approaches. In such an example, the local modifications may extend substantially across the entire substrate, or at least a majority of the substrate. Accordingly, a quasi-global modification may be achieved.

[0030] For example, the placement parameters may include a placement pattern of multiple modifications within the first substrate. For example, the placement pattern may include a rectangular pattern in which the modifications are placed such that the envelope of the modifications into the substrate substantially resembles a rectangular shape. The placement pattern may also include a circular pattern in which the modifications are placed such that the envelope of the modifications into the substrate substantially resembles a circular shape. However, any other geometric pattern of placement (e.g., an elliptical pattern, a polygonal pattern, etc.) may also be contemplated. For example, for a particular bonding process (e.g., to a particular second substrate), a particular modification pattern may need to be implemented in the first substrate for effective conditioning.

[0031] In one example, the placement parameters may include the number of modifications present in the plurality of local modifications. Thus, the number of modifications within the substrate may be adaptable to enable conditioning of the first substrate in a customizable manner (e.g., considering bonding of the first substrate to a second substrate). For example, for a particular bonding process (e.g., to a particular second substrate), a certain number of modifications within the first substrate may need to be implemented to enable effective conditioning.

[0032] In one example, the placement parameters may also include a spacing distance between the multiple local modifications. The spacing distance may include the distance (lateral or vertical) from the center of a first modification to the center of an adjacent second modification of the multiple local modifications. Thus, the spacing distance between the local modifications may be adaptable to enable conditioning in a customizable manner (e.g., considering bonding of a first substrate to a second substrate). For example, for a particular bonding process (e.g., to a particular second substrate), it may be necessary to implement a certain spacing distance (lateral or vertical) within the first substrate for effective conditioning. The spacing distance may be between 1 mm and 100 mm, preferably between 2 mm and 50 mm, more preferably between 5 mm and 20 mm, and most preferably between 8 mm and 15 mm. For example, the spacing distance may be 10 mm. In one example, the spacing distance may be considered the lateral resolution of the pixel grid (as described herein). In other examples, for example, the vertical spacing distance may be between 1 μm and 800 μm, such as between 2 μm and 400 μm. In one example, the spacing distance may be considered the vertical resolution of the pixel grid (as described herein).

[0033] In one example, the placement parameters may include a spatial order of the multiple local modifications, for example, the multiple local modifications may be positioned substantially along a two-dimensional plane within the substrate.

[0034] In another example, the multiple local modifications may be positioned substantially along two or more two-dimensional planes within the substrate. Thus, the multiple local modifications may be positioned in a three-dimensional arrangement within the substrate (e.g., a first plane having a first number of modifications, a second plane having a second number of modifications, and the first and second planes being separated by a (predetermined) spacing distance).

[0035] Furthermore, applying a plurality of local modifications within the first substrate may include a first local modification of the plurality of local modifications including a first local modification parameter and a second local modification of the plurality of local modifications including a second local modification parameter different from the first local modification parameter. As described herein, a local modification (e.g., also referred to as a pixel) may induce one or more forces along one or more axes within the substrate. Characteristics of the locally induced (mechanical) forces may be adaptable for each modification (e.g., pixel by pixel) of the plurality of modifications.

[0036] Thus, the multiple local modifications may be thought of as a pixel grid within the first substrate, with each pixel having a variety of states. Thus, highly customizable conditioning of the first substrate may occur in light of bonding to the second substrate. For example, a pixel may include an (adaptable) first force vector along a first force axis and an (adaptable) second force vector along a second force axis, where the first axis may be orthogonal to the second axis. Thus, the local modification parameters of a pixel may include, for example, the pixel's alignment (with respect to a reference orientation), the magnitude of the first force, and / or the magnitude of the second force (as described herein). Thus, every pixel may generate defined three-dimensional, two-dimensional, and / or one-dimensional mechanical effects that may be used to locally and / or globally condition the first substrate in a highly customizable manner. In another example, the local modification parameters may include the pixel's location within the substrate. For example, the location may be defined via coordinates along a predetermined depth plane within the substrate. The location may also include a three-dimensional specification of pixel coordinates (e.g., the location may be defined, for example, via a Cartesian coordinate system via x, y, z coordinates, and / or any other suitable coordinate system). The coordinates may, for example, correspond to the location of the center of the pixel.

[0037] In one example, the application of the multiple local modifications to the first substrate may be based at least in part on a trigger (e.g., information) that the first substrate is to be bonded to a second substrate. This may enable an automated approach to performing the method. For example, the method may include receiving a trigger that the first substrate is to be bonded to a second substrate. Based on this, a predetermined recipe of the method may be initiated to perform the method according to the present invention. In particular, the method may also be performed manually (e.g., an operator may initiate the application of multiple local modifications to the first substrate in view of the information, e.g., a visual / auditory alert, that the first substrate is to be bonded to a second substrate).

[0038] In one example, the application of the plurality of localized modifications within the first substrate may be further based at least in part on properties of the second substrate and / or the first substrate.

[0039] For example, the plurality of local modifications may be predetermined and / or customizable taking into account characteristics of the first substrate and / or the second substrate, which may include geometric characteristics of the first substrate and / or the second substrate (e.g., geometric shapes as described herein for the second substrate).

[0040] For example, a first substrate may be intentionally conditioned taking into account the geometric characteristics of a second substrate. This may enable customizable conditioning of the first substrate taking into account the second substrate. A typical conditioning technique for bonding substrates may not necessarily consider conditioning of the first substrate taking into account the characteristics of the second substrate to be bonded to the first substrate. For example, in known typical global conditioning techniques (e.g., via wet cleaning or plasma treatment), the global conditioning may be performed in a constant and / or stable manner using the same process parameters (e.g., the same cleaning chemistry, the same plasma parameters (such as plasma pressure)) applied to the conditioning. In such examples of typical global conditioning, the conditioning may not be adapted (or even adaptable) to take into account the characteristics of a specific substrate. However, the present invention enables customizable conditioning that takes into account the characteristics of a specific substrate, enabling a wider range of possible conditioning effects.

[0041] According to this example, the first substrate may also be purposefully conditioned to take into account the properties (e.g., geometric properties) of the first substrate. The conditioning of the first substrate may therefore be customizable to take into account its own geometric conditions.

[0042] In one example, the method may include determining a characteristic of the second substrate (e.g., via measurements of the second substrate). In one example, the method may include receiving a characteristic of the second substrate (e.g., via a wireless or wire-based data link).

[0043] In one example, the method may include determining and / or measuring a property of the second substrate and / or the first substrate.

[0044] In one example method, at least one substrate may comprise one or more desired process structures. For example, a first substrate may comprise one or more desired process structures and a second substrate may comprise one or more desired process structures. To further illustrate the example, a first substrate may comprise one or more process structures and a second substrate may also comprise one or more process structures.

[0045] The desired process structure may include an intentionally manufactured structure. For example, the desired process structure may be structured through one or more semiconductor manufacturing processes, as known in the semiconductor art. The desired process structure may be, for example, on the surface of a substrate. The desired process structure may be manufactured to have a defined desired geometric shape. It may therefore be identified as an object on a substrate having certain spatial dimensions. For example, the fabrication of the desired process structure may be based on one or more lithography processes. The fabrication of the desired process structure may also be based on one or more etching processes. The desired process structure may also be fabricated to have one or more desired materials. For example, the fabrication of the desired process structure may be based on one or more material processes (e.g., material deposition, oxidation, implantation). In one example, the desired process structure may be an etched structure simply etched into the material of the substrate. In a further example, the desired process structure may be a more complex structure. For example, the desired process structure may have at least one material different from the material of the substrate. For example, the desired process structure may include a metal. The metal may result from a corresponding deposition process on the substrate. In one example, the desired process structure may include a semiconductor (e.g., an intentionally doped semiconductor). For example, the intentionally doped semiconductor of the desired process structure may result from a semiconductor deposition process and / or implantation process of the substrate. The desired process structure may also include an insulator (e.g., an intentionally fabricated insulator or dielectric) resulting from a corresponding manufacturing process. An insulator may generally include, for example, an oxide or a dielectric. In one example, the desired process structure may include a resist structure. In one example, the resist structure may be filled with a dielectric.

[0046] The desired process structure may be referred to as a semiconductor structure, as understood in the field of semiconductor technology. For example, the semiconductor structure may comprise a semiconductor device (e.g., a transistor, a diode, a capacitor, a resistor, etc.). The semiconductor structure may also comprise a preform of a semiconductor device.

[0047] The desired process structures may also include alignment structures (eg, alignment marks) or verification structures (eg, test structures).

[0048] A substrate having a desired process structure may also be referred to herein as a structured substrate. In particular, the methods as described herein may therefore be used to condition the bonding of substrates, where at least one substrate is a structured substrate.

[0049] In one example, the first substrate and the second substrate may not be unstructured substrates. In this regard, the method may therefore not be considered a simple conditioning of an unstructured substrate. Rather, the method may be used to condition a bond in which both substrates are structured substrates. This may require more sophisticated control of the characteristics of the multiple local modifications (as described herein) to ensure reliable functionality of the desired process structures already present on the substrates.

[0050] In one example, applying a plurality of local modifications to a first substrate may induce a first target geometric shape for the first substrate. For example, the first substrate may initially comprise an original geometric shape. By applying a plurality of local modifications to the first substrate, the first substrate may undergo a change from the original geometric shape to the first target geometric shape.

[0051] For example, the first target geometry may relate to the global and / or local geometry of the first substrate. For example, application of multiple local modifications may induce global changes to the entire first substrate such that the global target geometry is induced. In another example, application of multiple local modifications may induce local changes within some regions and / or some volumes of the first substrate. (In this case) the remainder of the first substrate may not have significant changes in their geometry.

[0052] In one example, the first target geometry may include a substantially flat geometry of the first substrate. The substantially flat geometry may include relatively little substrate curvature and / or warpage (e.g., to the same extent as the substrate's base material). Local modifications may therefore also be used to create a substantially ideal flat geometry of the first substrate.

[0053] In one example, the method includes determining a first target geometry (e.g., which may also be referred to as deriving a first target geometry). For example, the first target geometry may be based on a simulation and / or calculation (e.g., based on the geometry of the second substrate as described herein). In one example, the method may include determining a plurality of local modifications to induce the first target geometry. For example, the determining may include determining what local modification parameters a pixel (of the plurality of local modifications) should have to induce the first target geometry. The determination of the plurality of local modifications may be (also) based on a simulation, which may include, for example, a simulation model of the first substrate, and the local modifications (e.g., pixel) may be applied to the simulation model to determine what shape is induced. The desired first target geometry (and / or local modification parameters of the pixel) may be determined iteratively, for example, within the simulation.

[0054] In one example, the first target geometry may be predetermined such that, when the first substrate and the second substrate are bonded, at least one bond quality parameter is improved compared to when no conditioning occurs. Thus, the present invention may be used to improve the bond quality of a first substrate with a second substrate. For example, the at least one bond quality parameter may include at least one of the following: yield of the bonding process, bond strength, bond-induced defect density, and bond interface quality. In the semiconductor technology field, such bond quality parameters may be determined in a quantitative manner, for example, for process control purposes. Improvement of the at least one bond quality parameter may thus be determined and / or verified via split groups. For example, a first split group of one or more substrate pairs may be subjected to conditioning according to the present invention, while a second (reference) split group of one or more substrate pairs may not be subjected to conditioning according to the present invention. Bonding of one or more substrate pairs may thus be performed to determine a statistical trend of the at least one bond quality parameter depending on the split group. For example, if at least one bond quality parameter is statistically better for the first divided group than for the second divided group, the conditioning effect of this example is satisfied.

[0055] In one example, the method may include determining a first target geometry such that, when the first and second substrates are bonded, at least one bond quality parameter is improved compared to when no conditioning occurs. The determining may be based on simulations and / or calculations (as described herein). In particular, the bond itself (e.g., its physical and / or chemical stresses) may also be simulated to determine an optimal first target geometry (e.g., such that physical and / or chemical stresses are minimized during bonding compared to when no conditioning occurs).

[0056] In one example, the split group analysis method described herein may also be used to optimize and / or determine a first target geometry. For example, it may be iteratively verified whether a first target geometry induces improved bonding quality for various first target geometries. For example, the first target geometry may include a fixed first target geometry (i.e., application may induce a fixed target geometry in any substrate intended for bonding to an additional substrate). In such a case, the split group analysis may be performed on two or more first target geometries to determine an optimal first target geometry.

[0057] In one example, the first target geometry may be based at least in part on a predetermined geometry of the second substrate. The predetermined geometry of the second substrate may include measurements of the geometry of the second substrate. In one example, the method may include determining the geometry of the second substrate (e.g., via measurements of the first substrate). In one example, the method may include receiving the predetermined geometry of the second substrate (e.g., via a wireless or wire-based data link).

[0058] In one example, the predetermined geometry of the second substrate may include the overall geometry of the second substrate, which may include a substrate geometry that substantially relates to the entire surface (e.g., front, back, and / or side) of the substrate and / or the entire volume of the substrate (e.g., three-dimensional characteristics of the substrate).

[0059] In one example, the overall geometry of the second substrate may include a surface topography and / or one or more deviations of the second substrate from a substrate reference plane. For example, the surface topography may include a surface topography obtained via optical topography measurements of the front and / or back surfaces of the second substrate. The surface topography may also include a surface topography obtained via profilometry measurements of the front and / or back surfaces of the second substrate.

[0060] The one or more deviations of the second substrate from a substrate reference plane may include at least one of the following: curvature, warpage, and / or total thickness variation (TTV) of the second substrate. In the semiconductor field, such deviations from a compliant reference plane are well known and may be determined in quantitative ways.

[0061] In one example, the global geometry may include a deviation map of the substrate indicating deviations (e.g., spatial deviations) for two or more locations of the second substrate relative to a corresponding reference surface of the second substrate. The deviation map may be used, for example, as a starting point for determining the curvature, warpage, and / or total thickness variation of the second substrate (as referred to herein). However, the deviation map (e.g., its data points) may also be used by itself to accommodate the application of multiple local modifications.

[0062] In one example, the overall geometric shape may include a deviation map signature. For example, it may be predetermined that a certain type of bending of the second substrate may occur, so that the deviation map of the second substrate may include one or more specific signature deviations. For example, the deviation map signature may include a saddle-shaped surface, a convex surface, a concave surface, and / or any other characteristic surface shape of the deviation map.

[0063] In one example, the overall geometry may include bending and / or folding of the second substrate. In one example, the deviation map of the substrate may include a deviation map indicating bending and / or folding of the second substrate for two or more locations of the second substrate.

[0064] In one example, the first target geometry of the first substrate may at least partially correspond to the predetermined geometry of the second substrate. Application of multiple modifications to the first substrate may be capable of generating a variety of (customizable) first target geometries, so that the induced first target geometry can (at least partially) match the predetermined geometry of the second substrate. For example, it may be conceivable that the first target geometry of the first substrate corresponds to a portion of the area and / or a portion of the volume of the predetermined geometry of the second substrate.

[0065] For example, the predetermined geometric shape of the second substrate may include a deviation map indicating (spatial) deviations for multiple locations on the second substrate. The first target geometric shape may then be determined such that at least a quasi-deviation map of the first substrate corresponds at least partially to the deviation map of the second substrate. For example, the first target geometric shape may be determined such that a central area of ​​the first target geometric shape substantially corresponds to a central area of ​​the predetermined geometric shape (as can be verified via the deviation map). For example, the first target geometric shape may be determined such that an outer edge area of ​​the first target geometric shape substantially corresponds to an outer edge area of ​​the predetermined geometric shape. In another example, the first target geometric shape may be determined such that substantially the entire first target geometric shape corresponds to the entire predetermined geometric shape.

[0066] In one example, the method of the first aspect may further include applying a plurality of local modifications in a second substrate. In particular, since the first substrate may be for bonding to a second substrate, the second substrate may also be conditioned to facilitate bonding of the first substrate to the second substrate.

[0067] In this regard, any aspects described with respect to conditioning a first substrate may be applied accordingly to conditioning a second substrate, for example, applying a plurality of localized modifications within the second substrate may be based at least in part on properties of the first substrate.

[0068] In particular, the order of application of multiple local modifications in the second substrate may not necessarily be limited, for example, the application of multiple local modifications in the second substrate may occur before, after, or between the application of local modifications in the first substrate.

[0069] In one example, applying multiple local modifications into the second substrate may induce a second target geometry of the second substrate.

[0070] In one example, applying the multiple local modifications to the second substrate may be based at least in part on a predetermined geometry of the first substrate. Thus, the original geometry of the first substrate may be taken into consideration when applying the multiple local modifications to the second substrate (even when a first target geometry is induced). The predetermined geometry of the first substrate may include the overall geometry of the first substrate. In one example, the overall geometry of the first substrate may include the surface topography (as described herein for the overall geometry of the second substrate) and / or one or more deviations of the first substrate from a substrate reference plane.

[0071] In one example, the second target geometry may be predetermined such that when the first substrate and the second substrate are bonded, at least one bond quality parameter is improved compared to when no conditioning occurs.

[0072] In one example, the second target geometry may be based at least in part on the first target geometry, or vice versa.

[0073] For example, the first target geometry may at least partially correspond to the second target geometry (or vice versa). In one example, the first substrate and the second substrate may be adapted so that they are both substantially flat. In this case, at least one substrate may have relatively less curvature or warpage than, for example, before applying the localized modifications in the first substrate and / or the second substrate. In another example, the first substrate and the second substrate may be adapted so that they are both substantially bent or folded. In this case, at least one substrate may have relatively more curvature or warpage than, for example, before applying the localized modifications in the first substrate and / or the second substrate.

[0074] In one example, the first target geometry may be different from the second target geometry such that bonding the first and second substrates may result in improved bond quality parameters compared to when no conditioning occurs. It may be possible to facilitate bonding by creating a predetermined mismatch between the first and second target geometries to improve bond quality. This may be due to high physical and / or chemical stress during bonding, and the predetermined mismatch may actively induce ease of bonding of the substrates. In one example, the first and second target geometries that improve at least one bond quality parameter may be determined or verified via split group analysis (as described herein). In another example, the different first and second target geometries may be based at least in part on simulation.

[0075] In one example, the method of the first aspect may include transmitting the target geometry of at least one of the substrates to a device for further processing of at least one of the substrates, in particular a bonding device for bonding the first substrate and the second substrate. For example, the bonding device may take into account the target geometry of at least one of the substrates to bond the first substrate to the second substrate. This may enable the bonding device to recognize the conditioning performed via the method according to the present invention. For example, the bonding device may adapt one or more bonding process parameters based on the target geometry of at least one of the substrates.

[0076] In one example, applying a plurality of localized modifications within the first substrate and / or the second substrate may be adapted so that, when the first substrate and the second substrate are placed in a bonding position, at least one localized bonding region of the first substrate and a corresponding localized bonding region of the second substrate have substantially the same curvature. For example, the bonding position may include the first substrate and the second substrate being placed on top of each other. For example, the corresponding bonding regions may include opposing and / or adjacent regions of the first substrate and the second substrate at the bonding position. The bonding position may include the presence of at least one intermediate (bonding) material between the two substrates.

[0077] Ensuring that corresponding bonding regions of a first substrate and a second substrate have substantially the same curvature (e.g., local curvature along one or more axes) can ensure interconnectivity and / or improved geometric alignment of the bonding regions, thereby improving bonding. The same curvature for corresponding bonding regions can enable, for example, a key-lock principle in which the lower surface of the upper substrate substantially aligns with the upper surface of the lower substrate in the bonding position. When a structured pattern is present on one of the substrates, the curvature of the corresponding bonding regions can include a curvature defined via an envelope cover or more structured patterns.

[0078] The structured pattern may comprise two or more desired process structures (as described herein). The structured pattern may also be a desired process structure (as described herein).

[0079] Using such an approach, air gaps between the substrates and / or variations in thickness of the intermediate (bonding) layer may be minimized, which may improve at least one bond quality parameter.

[0080] In one example, applying multiple local modifications within a first substrate and / or a second substrate may be adapted so that when the first substrate and the second substrate are placed in a bonding position, structures of the first substrate are substantially aligned with corresponding structures of the second substrate. For example, without the conditioning of the present invention, the first substrate and the second substrate may fold when placed in a bonding position such that corresponding structures (e.g., to be bonded to each other) may not be substantially aligned. The method of the present invention may therefore be able to facilitate alignment of substrates for bonding through highly customizable conditioning. For example, the conditioning may be used to facilitate overlay of alignment marks on the substrates.

[0081] In one example, application of multiple local modifications within a first substrate may induce a (predetermined) positional correction of at least one structure of the first substrate. Thus, the method of the present invention may not be limited to conditioning effects that merely accommodate (local or global) bending of the substrate (e.g., warping, curvature, topography, etc.) as described herein. A second conditioning effect may also be induced that includes precise local positional correction of at least one structure of the first substrate. This may be possible due to the high degree of freedom to which pixels may be applied, with each pixel inducing a freely customizable effect (e.g., via different forces along different axes of the substrate). In this regard, changes in the topography of the substrate (i.e., the first conditioning effect) may be interleaved with local positional correction of the structure (i.e., the second conditioning effect). However, positional correction alone may also be implemented as conditioning.

[0082] At least one structure of the first substrate may comprise a desired process structure (as described herein).

[0083] For example, the position correction may include overlay correction. The overlay correction may include pattern-to-pattern alignment error, which may result from lithography overlay error and / or other pre-processing deviations of the first substrate. In particular, the method may include determining (e.g., measuring) the overlay error and / or receiving the overlay error. For example, the method may include determining (or receiving) a position of a structure, which may be compared to a target position of the structure. In one example, the position correction may be applied to multiple structures, e.g., structures across the first substrate, to globally correct the overlay error for the entire first substrate.

[0084] In one example, the position correction may be applied to the second substrate.

[0085] In one example, applying the multiple local modifications may include applying one or more pulses of electromagnetic radiation to a corresponding substrate to cause a corresponding multiple local modifications in the substrate. For example, the electromagnetic radiation may be focused in (or on) a first substrate to cause the local modifications in the first substrate, and / or the electromagnetic radiation may be focused in (or on) a second substrate to cause the local modifications in the second substrate. In one example, the local modifications may be induced within an effective area of ​​a focus of the electromagnetic radiation.

[0086] The source of electromagnetic radiation may include a laser. The wavelength of the electromagnetic radiation (e.g., a laser wavelength) may include wavelengths from 1 μm to 20 μm. In one example, the electromagnetic radiation may include wavelengths from (preferably) 1 μm to 15 μm, (preferably) 1 μm to 12 μm, (preferably) 1 μm to 8 μm, (preferably) 1 μm to 3 μm, and / or (preferably) 1 μm to 2 μm.

[0087] In one example, the electromagnetic radiation may include wavelengths between 1000 nm and 2000 nm. For example, the wavelengths may include wavelengths between 1060 nm and 1070 nm, e.g., about 1064 nm. In another example, the wavelengths may include wavelengths between 1530 nm and 1570 nm, e.g., about 1550 nm. In yet another example, the wavelengths may be selected to be within the range of 1060 nm to 1570 nm.

[0088] The pulse duration of one of the one or more pulses of electromagnetic radiation may include a duration of 1 femtosecond (fs) to 100 microseconds (μs). In one example, the pulse duration may include a duration of 100 fs to 1 μs, (preferably) 500 fs to 500 ns, (preferably) 600 fs to 300 ns, (preferably) 700 fs to 200 ns, or (preferably) 800 fs to 100 ns.

[0089] By adapting one or more optical properties of the electromagnetic radiation and / or its focal properties, the properties of the local modification (i.e., pixel) may be adapted. The adaptation of the electromagnetic radiation may be performed via an optical setup that can optically affect the electromagnetic radiation. For example, the optical setup may include one or more optical elements (e.g., lenses, beam shaping elements, wave shaping elements, focusing elements, diffractive optical elements, beam splitters, etc.) that may be controlled to induce specific properties of the pixel. For example, by controlling the properties of the electromagnetic radiation, the local modification parameters of the pixel (e.g., pixel alignment, magnitude of the pixel's first force and / or second force) may be precisely controlled.

[0090] In one example, the local modification parameters of a pixel may include characteristics of the pixel (where the pixel is referred to therein, for example, as an expansion region or a deformation) as described in U.S. Patent Publication No. 20170010540. In particular, Figures 8 and 9 of U.S. Patent Publication No. 20170010540 illustrate the concept of a pixel (e.g., as described herein) and indicate the magnitude of the expansion (of a pixel) versus its direction in space.

[0091] In one example, U.S. Patent Publication No. 20170010540 may be considered a technology platform for the present invention. Local modifications may be adapted for different purposes as described therein. Thus, the present invention may include using this technology platform to implement aspects described herein for conditioning substrates (e.g., for bonding substrates). For example, multiple modifications may be adaptable and / or controllable in a manner similar to that described in U.S. Patent Publication No. 20170010540. For example, local modification parameters of a pixel may be adapted by adapting the beam shape of electromagnetic radiation (e.g., laser pulses) as described in U.S. Patent Publication No. 20170010540. In one example, U.S. Patent Publication No. 20170010540 is incorporated herein by reference in its entirety.

[0092] In one example, the method may further include performing a calibration, where the calibration includes applying a plurality of local modifications to the calibration substrate. The calibration may further include determining characteristics of at least one of the plurality of local modifications and / or a geometry of the calibration substrate. Based on these calibration results, the application of the plurality of local modifications may be adapted to the conditioning as described herein.

[0093] In one example, the conditioning may be performed before bonding of the first substrate and the second substrate occurs, and the method may therefore be applied as a pre-conditioning for bonding.

[0094] In one example, conditioning may be performed after bonding of the first and second substrates has occurred. The method may be applied, for example, to a pair of already bonded substrates as post-bond conditioning, where the bonded pair of substrates includes a first and a second substrate. For example, this may allow for improved relaxation of the first and second substrates after bonding. Furthermore, it may allow for correction of errors induced during bonding (e.g., unwanted bending of the substrates or unwanted positional errors of the structures).

[0095] In particular, conditioning of the bonded first and second substrates may be performed as a pre-treatment for further processing of the bonded substrate pair including the first and second substrates. For example, the further processing may include subsequent lithography processes / patterning, thinning (e.g., grinding and / or etching), and / or measurement of the bonded substrate pair. For example, a first and / or second target geometry may be induced (as described herein) to facilitate further processing of the bonded first and / or second substrates. For example, the bonded substrate pair (including the first and second substrates) may be conditioned to have a substantially flat geometry (as described herein).

[0096] In one example, the method may include bonding a first substrate to a second substrate. Thus, the method of the first aspect may not be limited to conditioning the substrates, but may also include bonding the first substrate to the second substrate.

[0097] In one example, during bonding, one or more bonding process parameters may be based at least in part on conditioning (as described herein). This may enable accurate bonding that takes conditioning into account in accordance with the present invention. For example, during bonding, one or more bonding process parameters may be based at least in part on a target geometry of the first (and / or second) substrate.

[0098] In one example, the first substrate may comprise a wafer. The wafer may comprise a semiconductor-based wafer (e.g., a wafer including a semiconductor, such as silicon, gallium nitride, silicon carbide, gallium arsenide, etc.). The wafer may be substantially circular in shape. In one example, the diameter of the wafer may comprise a diameter between 1 inch and 24 inches. For example, the diameter of the wafer may comprise a diameter of substantially 300 millimeters (e.g., 12 inches). In another example, the diameter of the wafer may comprise a diameter of substantially 200 millimeters (e.g., 8 inches). In another example, the diameter of the wafer may comprise a diameter of substantially 150 millimeters (e.g., 6 inches). However, any other wafer diameter may be suitable for the methods described herein.

[0099] In one example, the second substrate may also comprise a wafer (e.g., having the properties described for the first substrate), and the corresponding invention may therefore be used to condition the bond between the wafers.

[0100] In another example, the second substrate may be a chip and / or die. In such an example, the chip and / or die may have a smaller diameter than the first substrate. In another example, the second substrate may be a chip and / or die, and the first substrate may be a wafer (as described herein). Accordingly, a corresponding invention may be used to condition a wafer-to-die bond and / or a wafer-to-chip bond. In one example, when the second substrate may be a chip and / or die, only the first substrate may be conditioned (as described herein).

[0101] A second aspect relates to a method for conditioning a first substrate, including receiving a second characteristic of the second substrate and determining, at least in part based on the second characteristic, a plurality of local modifications to be applied within the first substrate, the local modifications may be determined, for example, to facilitate bonding of the first substrate and the second substrate.

[0102] In some examples, the method according to the second aspect may further include receiving a first characteristic of the first substrate and a second characteristic of the second substrate. Determining the plurality of local modifications may be based at least in part on the first characteristic and / or the second characteristic, for example, to facilitate bonding of the first substrate and the second substrate.

[0103] For example, the second aspect may include calculating pixels and their local modification parameters. The method of the second aspect may be performed on a computing unit that may be configured to send and receive data to perform the methods described herein.

[0104] In particular, any feature described with respect to the first aspect (or any other aspect described herein) may be included as a feature of the method according to the second aspect (where applicable, and vice versa). For example, the method of the second aspect may include any method step as described with respect to the method of the first aspect.

[0105] In one example, the properties of the first substrate and / or the second substrate may include the geometry of the first substrate and / or the second substrate, respectively (as described herein).

[0106] In one example, the method of the second aspect may further include deriving a first target geometry for the first substrate to facilitate bonding of the first substrate and the second substrate, and a plurality of local modifications to be applied within the first substrate are determined to induce the first target geometry for the first substrate.

[0107] In one example, the method of the second aspect may further include determining, based at least in part on the first characteristic and / or the second characteristic, a plurality of local modifications to be applied within the second substrate to facilitate bonding of the first substrate and the second substrate.

[0108] In one example, the method of the second aspect may further include deriving a second target geometry for the second substrate to facilitate bonding of the first substrate and the second substrate, and a plurality of local modifications to be applied within the second substrate are determined to induce the second target geometry for the second substrate.

[0109] A third aspect relates to a method for conditioning bonded substrates, comprising applying a plurality of localized modifications within a first substrate bonded to a second substrate. The method of the third aspect may therefore relate to a pair of bonded substrates, the pair of substrates comprising a first substrate and a second substrate. The method of the third aspect may include features described herein for the corresponding example of the first aspect (related to performing conditioning after bonding of the first and second substrates has occurred). In particular, any features described for the first and / or second aspects (or any other aspect described herein) may be included as features of the method according to the third aspect (where applicable).

[0110] For example, the method of the third aspect may include at least one step of the method of the first and / or second aspect.

[0111] A fourth aspect relates to a method for bonding a first substrate and a second substrate, comprising adapting one or more bonding process parameters based at least in part on conditioning the bond according to the method of the first, second, and / or third aspects (or any other aspect described herein).

[0112] In particular, any feature described with respect to the first, second and / or third aspect (or any other aspect described herein) may be included as a feature of the method according to the fourth aspect (where applicable, and vice versa).

[0113] A fifth aspect relates to a method for conditioning a substrate, comprising applying a plurality of localized modifications in a first substrate based at least in part on properties of a second substrate. In particular, any feature described for the first, second, third and / or fourth aspects (or any other aspect described herein) may be included as a feature of the method according to the fifth aspect (where applicable, and vice versa).

[0114] In one example of the method according to the fifth aspect, a first substrate may be conditioned with respect to a second substrate, as it is not necessary to condition the substrate with respect to another process (e.g., bonding), for example, the first substrate may be conditioned with respect to the properties of the second substrate for calibration purposes.

[0115] For example, the second substrate may have already undergone conditioning, and thus, based on the characteristics of the second substrate (e.g., geometric shape, as described herein, for example), the conditioning of the first substrate may be adapted, for example, to achieve optimal conditioning effects.

[0116] A sixth aspect relates to a computer program comprising instructions for performing a method according to any of the first, second, third, fourth and / or fifth aspects when the computer program is executed.

[0117] In one example, the computer program may perform steps for determining a plurality of local modifications to be applied within the first substrate and / or the second substrate to facilitate bonding between the first substrate and the second substrate.

[0118] A seventh aspect relates to an apparatus for conditioning bonding of substrates, comprising: means for applying a plurality of local modifications within a first substrate to facilitate bonding of the first substrate to a second substrate; and a control unit configured to control the apparatus to perform a method according to any of the methods of the first, second, third, fourth, and / or fifth aspects. The control unit may comprise, for example, a computer, computing entity, processor that may adapt one or more system parameters of the apparatus (e.g., system parameters of the optical setup of the apparatus) to cause the apparatus to perform a method described herein. In one example, the control unit may comprise storage, which may comprise a computer program according to the sixth aspect. The apparatus may thus be configured to execute the computer program of the sixth aspect. This may enable the control unit to control the apparatus to perform a method as described herein.

[0119] In one example, the apparatus may comprise means for determining a plurality of local modifications into a substrate for a method described herein. The determining means may be comprised in a control unit (and may comprise a corresponding computer program). For example, the determining means may be configured to determine a plurality of local modifications into a first substrate to facilitate bonding of the first substrate to a second substrate (e.g., to perform a method according to the first aspect or any other aspect described herein). In one example, the determining means may be configured to determine the plurality of local modifications into the first substrate based at least on characteristics (or parameters) of the second substrate.

[0120] For example, the determining means may determine, via simulation and / or calculation, what modification parameters the pixels of the plurality of local modifications should have so that a first target geometric shape of the first substrate is induced, and the first target geometric shape may be based on characteristics of the second substrate. The determining means may therefore also determine the first target geometric shape via simulation and / or calculation, for example, taking into account a predetermined geometric shape and / or position of a structure of the second substrate.

[0121] In one example, the control unit may be configured to receive information that a first substrate is to be bonded to a second substrate and to control the apparatus to perform the method based at least in part on the information, which may include a trigger signal, a flag, and / or a manual input.

[0122] In one example, the means for applying may comprise a source for generating one or more pulses of electromagnetic radiation and a first element for focusing a beam of electromagnetic radiation to a predetermined focal depth within the first substrate.

[0123] In one example, the means for applying may further comprise at least one of the following: a first element for adapting a wavefront of the electromagnetic radiation; means for splitting the beam of electromagnetic radiation into a plurality of split beams.

[0124] In one example, the apparatus may further include a means for positioning the first substrate to control the local position of at least one local modification among the plurality of local modifications. For example, the positioning may include rotating the first substrate (via the positioning means). For example, the first substrate may be positioned at a first position within a first application field (e.g., within a limited region or volume of the first substrate) where a first set of local modifications is applied to the first substrate. The first substrate may then be rotated (e.g., via rotation of the positioning means) to a second position within a second application field where a second set of local modifications is applied to the first substrate. Thus, the plurality of local modifications may be distributed / positioned within the first substrate by rotating the substrate. This may allow the complexity of positioning the interactions that induce the local modifications (e.g., positioning the optical paths of one or more laser pulses focused on the first substrate) to be reduced.

[0125] In particular, the means for positioning the first substrate may not necessarily be limited to rotation. For example, the means for positioning may position the first substrate via lateral movement of the substrate, where the lateral movement may be along one or more axes. The lateral movement may be combined with rotational movement. By enabling lateral movement in combination with rotational movement, the local modifications may be positioned at (substantially) any position within the first substrate. In one example, the means for positioning may be adapted to perform rotation of the first substrate in combination with lateral movement of the first substrate along one or more axes, where the lateral movement may include movement in opposite directions of the axes. Thus, by rotating the first substrate and lateral movement, a set of local modifications may be applied in a spiral pattern (as described herein).

[0126] In one example, the positioning means may allow three-dimensional positioning of the substrate within the apparatus, for example, the positioning means may thus allow not only lateral movement (along one or more axes) but also vertical movement of the first substrate within the apparatus.

[0127] The lateral and / or rotational movement of the first substrate described herein may include movement of the substrate in a plane (which may span the surface of the first substrate or may be parallel to the surface of the first substrate).

[0128] In one example, the positioning means may be configured to position a bonded substrate pair including a first substrate bonded to a second substrate. For example, the positioning means may be adapted to securely clamp the bonded substrate pair. For example, the positioning means may include a chucking system capable of securely holding the bonded substrate pair while a method according to one of the aspects described herein is performed. That is, typical means for positioning wafers may not necessarily be suitable for safely positioning a bonded substrate pair.

[0129] In one example, the positioning means may comprise a chuck and / or a stage. For example, the chuck may be adapted to contact and securely hold the bonded substrate pair. In one example, the chuck may be coupled to the stage to follow the movement of the stage, and the stage may be adapted to perform lateral, rotational, and / or three-dimensional movement as described herein. In another example, the chuck may perform lateral, rotational, and / or three-dimensional movement as described herein (the stage may follow the movement of the chuck, or, for example, there may be no stage).

[0130] In particular, properties of a first substrate and / or methods (or interactions) applied to the first substrate as described herein may also be properties of a second substrate and / or may be included herein as methods (or interactions) applied to the second substrate. Furthermore, properties of a second substrate and / or methods (or interactions) applied to the second substrate as described herein may also be properties of a first substrate and / or may be included herein as methods (or interactions) applied to the first substrate.

[0131] It should be noted that method steps (or computer program steps) as described herein may include all aspects as described herein, even if they are not explicitly described as method steps, but rather are described with reference to an apparatus (or device or system). Furthermore, an apparatus (or system or device) as outlined herein may include means for performing all aspects as outlined herein, even if they may rather be described in the context of method steps (or computer program steps).

[0132] The methods outlined herein may be computer-implemented.

[0133] The functions described herein, whether described as method steps, computer programs, and / or means, may be implemented in hardware, software, firmware, and / or combinations thereof. If implemented in software / firmware, the functions may be stored on or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a general-purpose computer or a special-purpose computer. By way of example, and without limitation, such computer-readable storage media may include RAM, ROM, EEPROM, FPGA, CD / DVD or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. A control unit as described herein may also be implemented in hardware, software, firmware, and / or combinations thereof, e.g., by one or more general-purpose or special-purpose computers and / or general-purpose or special-purpose processors. [Brief explanation of the drawings]

[0134] [Figure 1a] 1A-1C illustrate two examples for conditioning a substrate via local modification according to the present invention, where the conditioning induces a target geometry of the substrate. [Figure 1b] 1A-1C illustrate two examples for conditioning a substrate via local modification according to the present invention, where the conditioning induces a target geometry of the substrate. [Figure 2a]1A-1C show two examples for conditioning a substrate via local modification according to the present invention, where the conditioning induces positional corrections of structures on the substrate; [Figure 2b] 1A-1C show two examples for conditioning a substrate via local modification according to the present invention, where the conditioning induces positional corrections of structures on the substrate; [Figure 3] FIG. 1 shows a flow chart of an exemplary (conditioning) method of the present invention, in which the conditioning is performed as a preconditioning for bonding of substrates. [Figure 4a] 1A-1C show two examples for pre-conditioning of substrates for bonding of the substrates. [Figure 4b] 1A-1C show two examples for pre-conditioning of substrates for bonding of the substrates. [Figure 5] FIG. 1 shows a flow chart of an exemplary (conditioning) method of the present invention in which conditioning is performed as a post-conditioning after bonding of the substrates has occurred. [Figure 6] 10A-10C illustrate examples for post-conditioning of substrates according to the present invention after bonding of the substrates has occurred. [Figure 7a] 1A-1C show flow charts of two exemplary (conditioning) methods according to the present invention, in which the conditioning of the substrates is performed before and after bonding of the substrates. [Figure 7b] 1A-1C show flow charts of two exemplary (conditioning) methods according to the present invention, in which the conditioning of the substrates is performed before and after bonding of the substrates. [Figure 8a] 1A-1C illustrate examples for post-conditioning of a substrate according to the present invention where pre-conditioning of the substrate has occurred. [Figure 8b] 1A-1C illustrate examples for post-conditioning of a substrate according to the present invention where pre-conditioning of the substrate has occurred. [Figure 9a] 10A and 10B show experimental results of conditioning a substrate according to the present invention. [Figure 9b] 10A and 10B show experimental results of conditioning a substrate according to the present invention. [Figure 9c] 10A and 10B show experimental results of conditioning a substrate according to the present invention. [Figure 10a] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 10b] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 10c] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 11a] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 11b] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 11c] 10A-10C show further experimental results of conditioning a substrate according to the present invention. [Figure 12] 1 shows a first example of a device according to the invention; [Figure 13] FIG. 2 shows a second example of an apparatus according to the invention. [Figure 14] FIG. 3 shows a third example of a device according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0135] 1a / 1b show two schematic examples for conditioning a substrate via local modifications according to the present invention, in which the conditioning induces a target geometric shape for the substrate. The upper FIG. 1a discloses an example in which conditioning of a substantially curved (or folded) substrate W1 is performed according to the present invention. In this example, the substrate W1 may be a (semiconductor-based) first wafer W1. The first substrate W1 may have substantial wafer curvature and / or wafer bow, as indicated by the schematic curved shape in FIG. 1a. For example, conditioning may include applying multiple local modifications D within the first wafer W1. The multiple local modifications D may persist within the first wafer for an extended period of time (as described herein), such that the conditioning effect may also persist for an extended period of time. In this example, multiple local modifications D are applied (i.e., created) in the first wafer W1 such that the shape / geometry of the first wafer W1 is transformed from its original curved shape / geometry to a substantially flat shape / geometry via bending. For example, multiple local modifications D may be applied to reduce wafer curvature and / or wafer bow of the first wafer W1 after conditioning C.

[0136] The upper FIG. 1b discloses an example in which conditioning C of a substantially flat substrate W1 is performed according to the present invention. In this example, the first substrate W1 may have a relatively small wafer curvature and / or wafer bow before conditioning C, as indicated by the schematic curved shape in FIG. 1a. In this example, multiple local modifications are applied to the first wafer W1 as conditioning step C such that the shape / geometry of the first wafer W1 is transformed from its original flat shape / geometry to a substantially curved (or folded) shape / geometry via bending. For example, multiple local modifications D may be applied such that the wafer curvature and / or wafer bow of the first wafer W1 increases after conditioning C.

[0137] In one example, the multiple local modifications D may be adapted as described herein to induce a predetermined first target geometric shape (e.g., first target shape) of the first wafer W1.

[0138] 2a / 2b show two examples of conditioning a substrate via local modification according to the present invention, in which the conditioning induces positional correction of structures on the substrate as a conditioning effect. As indicated in FIG. 2a, conditioning C does not necessarily have to be performed to induce folding (or shape transformation) of the first wafer W1. Thus, after conditioning C, the wafer curvature and / or wafer bow of the first wafer W1 may be substantially the same. In the example of FIG. 2a / 2b, conditioning C of the first wafer W1 may be performed to induce positional correction (e.g., overlay error correction) of one or more structures on the first wafer. Thus, conditioning may include shifting structures along one or more axes. The positional correction may be performed in consideration of further processing of the first wafer W1 (as described herein), such as bonding the first wafer W1 to a second wafer W2.

[0139] In particular, the conditioning effect described with respect to Figures 1a / 1b may be combined with the conditioning effect described with respect to Figures 2a / 2b, and thus the conditioning according to the invention may induce not only bending of the first wafer W1 but also position correction of structures of the first wafer W1.

[0140] 3 shows a flowchart of an exemplary (conditioning) method 300 of the present invention in which conditioning is performed as a preconditioning for bonding of substrates. As generally described, the method may include conditioning C (e.g., of a first wafer W1 and / or a second wafer W2) and subsequent bonding of the first wafer W1 to the second wafer W2.

[0141] 4a / 4b show two examples for pre-conditioning of substrates for substrate bonding.

[0142] 4a and 4b show an example of pre-conditioning, in which a first wafer W1 is to be bonded to a second wafer W2. First, there is a conditioning step C, followed by a bonding process B between the first wafer W1 and the second wafer W2.

[0143] In the first preconditioning example of FIG. 4a, the first wafer W1 may originally have a substantially curved (or folded) shape. The second wafer W2 may originally have a substantially flat shape. For example, the wafer curvature and / or bow of the first wafer W1 may originally be greater than the wafer curvature and / or bow of the second wafer W2. The preconditioning may include substantially matching the shape (or wafer curvature / bow) of the (curved) first wafer W1 with the shape (or wafer curvature / bow) of the (flat) second wafer W2.

[0144] In the first pre-conditioning example of FIG. 4a, multiple local modifications D may be applied to the first wafer W1 to transform the shape of the first wafer W1 from its original (curved) shape to a first target geometric shape. For example, conditioning C of the first wafer W1 may induce the first wafer W1 to transform into a substantially flat shape such that both wafers W1, W2 have a substantially flat shape. In another example, the method may include, after conditioning C of the first wafer W1, both wafers W1, W2 have substantially the same wafer curvature and / or wafer bow. In another example, the method may include, after conditioning C, two or more corresponding points of the first wafer W1 and the second wafer W2 have substantially the same (local) deviation from the wafer reference plane. For example, the points may be addressed via wafer coordinates (x, y).

[0145] In the second preconditioning example of FIG. 4b, the first wafer W1 may originally have a substantially flat shape. The second wafer W2 may originally have a substantially curved (or folded) shape. For example, the wafer curvature and / or bow of the first wafer W1 may originally be smaller than the wafer curvature and / or bow of the second wafer W2. The preconditioning may include substantially matching the shape (or wafer curvature / bow) of the (curved) first wafer W1 with the shape (or wafer curvature / bow) of the (flat) second wafer W2.

[0146] In the pre-conditioning example of FIG. 4b, multiple local modifications D may be applied to the first wafer W1 to transform the shape of the first wafer W1 from its original (flat) shape to the first target geometric shape. For example, conditioning C of the first wafer W1 may induce the first wafer W1 to transform into a substantially curved (or folded) shape such that both wafers W1, W2 have a substantially curved (or folded) shape. In another example, the method may include, after conditioning C of the first wafer W1, both wafers W1, W2 have substantially the same wafer curvature and / or wafer bow. In another example, the method may include, after conditioning C, two or more corresponding points of the first wafer W1 and the second wafer W2 have substantially the same (local) deviation from a wafer reference plane.

[0147] Adapting the wafer shape of the first wafer W1 to take into account the characteristics of the second wafer W2, as described herein, can be advantageous for bonding B of the first wafer W1 to the second wafer W2. In a first example of preconditioning, bonding B may require placing the wafers in a bonding position where the first wafer W1 is above the second wafer W2. In a second example of preconditioning, bonding B may require placing the wafers in a bonding position where the second wafer W2 is above the first wafer W1. Without the conditioning described herein, the wafer shapes of the first wafer W1 and the second wafer W2 would be significantly different in their geometries (e.g., shape), and therefore one or more (large) gaps may exist at the bonding position. Such mismatch in wafer geometry can adversely affect the bonding process, which typically imposes significant physical and / or mechanical stress on both wafers. The present invention may enable the first and second substrates to be matched in shape when the wafers are placed in a bonding position, reducing the degree of geometric mismatch and facilitating bonding thereof. Thus, at least one bonding quality parameter may be improved through the conditioning of the present invention.

[0148] 5 shows a flowchart of an exemplary (conditioning) method 500 of the present invention in which conditioning is performed as post-conditioning after bonding of the substrates has occurred. Generally, the method may include bonding B (e.g., between a first wafer W1 and a second wafer W2) and subsequent conditioning of the first wafer W1 and / or the second wafer W2.

[0149] After post-conditioning C, further processing of the bonded substrates may occur. For example, the further processing may include a lithography process (e.g., lithography patterning) of the bonded substrate pair. In one example, post-conditioning C may induce a target geometry of the bonded substrate pair (or of at least one of the substrates) such that at least one lithography parameter is improved compared to when no conditioning occurs. Post-conditioning may therefore also be considered pre-conditioning for further processing (e.g., a lithography process). Also, if desired, one or more conditioning steps may be performed between bonding the substrates and further processing.

[0150] In one example, when lithography processing of a bonded substrate pair is desired, post-conditioning C may invoke a target geometry that improves the planarity of the bonded substrates. The bonded substrate pair may therefore be made more planar. The lithography processing may therefore be performed with a flatter bonded substrate pair (compared to when no post-conditioning occurs).

[0151] However, in another example, when lithography processing of a bonded substrate pair is desired, post-conditioning C may induce a target geometry that does not merely increase flatness, but rather introduces one or more intentional deviations from perfect flatness according to a target geometry (e.g., desired shape deviations) that can be taken into account in subsequent lithography processing. The desired shape deviations may be introduced throughout the bonded substrate pair, or may be introduced only locally while still inducing other regions to be flatter. For example, the target geometry may be such that the bonded substrate pair has one or more regions with a desired shape deviation that actually reduces flatness in those regions. In this regard, the desired shape deviations are formed to introduce a predefined error for the lithography processing of the bonded substrate pair. This predefined error may therefore be more easily handled when adapting and / or optimizing subsequent lithography processing. In this example, the bonded substrate pair is therefore shaped in a way that is not ideal with respect to overall flatness (e.g., the overall curvature of the bonded substrate pair may increase). However, non-ideal shapes may allow for improved lithographic results in further lithographic processing, as they constitute predefined errors that can be more easily reduced and / or taken into account during lithography (e.g., by adapting the optical properties of the lithography tool, as is known in the art of lithography).

[0152] FIG. 6 illustrates an example for post-conditioning of substrates according to the present invention after substrate bonding has occurred. The initial starting point in this example is bonding a first wafer W1 to a second wafer W2 to form a bonded wafer pair. In the illustrated example, the bonded substrate pair originally corresponds to a substantially curved (or folded) shape. However, any shape (or geometry) of the bonded substrate pair may be adaptable or conditioned as described herein. According to the present invention, conditioning C of the bonded wafer pair may include applying multiple local modifications within the first wafer W1 and / or the second wafer W2. In this example, modification D is applied within the second wafer W2. In this regard, conditioning C may induce the second wafer W2 to transform from its original shape to a (predetermined) target geometry. In this example, the target geometry of the second wafer includes a substantially flat wafer shape. Additionally, conditioning C may induce the second wafer W2 to transform from its original shape to a (predetermined) target geometric shape. Conditioning C may also induce the bonded substrate pair to transform from its original shape to a (predetermined) target geometric shape. As described herein, the target geometric shape and the effect of the local modifications may be determined via simulation (e.g., finite element simulation). For example, the simulation model may include a model in which the first wafer W1 is bonded to the second wafer W2. Through the simulation, various modifications within the first wafer W1 and / or the second wafer W2, the desired target geometric shape of the wafers and / or the bonded substrate pair may be determined.

[0153] 7a / 7b show flow charts of two exemplary (conditioning) methods according to the invention, in which conditioning of a substrate is performed before and after processing of the substrate (e.g., bonding of the substrate). Thus, a method according to the invention may include performing a first conditioning C1 (e.g., as pre-conditioning) and a second conditioning C2 (e.g., as post-conditioning) via multiple local modifications into the substrate.

[0154] 7a, the method may include pre-conditioning C1 of the first and / or second wafers (as described herein) to facilitate bonding of the first and / or second wafers. Subsequently, the first and second wafers W1, W2 may be bonded to one another via a bonding process B. Subsequently, post-conditioning C2 of the bonded substrate pair (as described herein) may occur to facilitate bonding (e.g., to improve the quality of the bond of the first and second wafers).

[0155] Post-conditioning C2 (of FIG. 7a) may also include post-conditioning that allows for further processing as described with respect to FIG.

[0156] In a second example shown in FIG. 7b, the method may include a first conditioning C1 (e.g., pre-conditioning) of the first and / or second wafers (as described herein) to facilitate bonding of the first and / or second wafers. Subsequently, the first and second wafers W1, W2 may be bonded to one another via a bonding process B. Subsequently, a first further processing T of the bonded substrate pair may occur. The first further processing T may include measurement of the bonded substrate pair. The first further processing T may also include thinning of the bonded substrate pair, for example, via (mechanical) grinding and / or etching of the surfaces of the bonded substrate pair. Subsequently, a second conditioning C2 (e.g., post-conditioning or pre-conditioning) of the bonded substrate pair (as described herein) may occur. The second conditioning C2 may be adapted as post-conditioning to facilitate bonding (e.g., to improve the quality of bonding of the first and second wafers). In another example, the second conditioning C2 may be adapted as a post-conditioning to improve results from or mitigate adverse effects from the first further process T (e.g., grinding / etching may induce mechanical stresses that may be mitigated via conditioning as described herein). In another example, the second conditioning C2 may include conditioning in consideration of a (subsequent) second further process L of the bonded substrate pair. The second conditioning C may, for example, function as a pre-conditioning of the bonded substrate pair to facilitate the second further process L. For example, the second further process L may include a lithography process (e.g., lithography patterning) of the bonded substrate pair. In particular, the second conditioning C2 may induce a target geometry of the bonded substrate pair (or at least one of the substrates) such that at least one lithography parameter is improved compared to when no conditioning occurs.In particular, all aspects described for the conditioning process may be applied to the first and / or second conditioning C1, C2.

[0157] Post-conditioning C2 (of FIG. 7a) may also include post-conditioning that allows for further processing as described with respect to FIG.

[0158] In one example, when lithography processing of a bonded substrate pair is desired, post-conditioning C2 may induce a target geometry that increases the planarity of the bonded substrates. The bonded substrate pair may therefore be made flatter. The lithography processing may therefore be performed with a flatter bonded substrate pair (compared to when no post-conditioning occurs).

[0159] However, in another example, when lithography processing of the bonded substrate pair is desired, post-conditioning C2 may induce a target geometry that does not merely increase flatness, but rather introduces one or more intentional deviations from perfect flatness with the target geometry (e.g., desired shape deviations) that can be taken into account by the subsequent lithography process L. The desired shape deviations may be introduced throughout the entire bonded substrate pair, or may be introduced only locally, where other regions are still induced to be flatter. The predefined errors may therefore be more easily handled when adapting and / or optimizing the subsequent lithography process (as described herein).

[0160] 8a / 8b show a schematic example for a second conditioning C2 (e.g., post-conditioning) of a substrate according to the present invention, where a first conditioning (e.g., pre-conditioning) of the substrate has already occurred. For example, the starting point of this exemplary method may include a first wafer W1 being bonded to a second wafer W2, and multiple local modifications D2 being applied within the second wafer W2 (e.g., in the first conditioning C1).

[0161] 8a, the second conditioning C2 may include applying multiple local modifications within a substrate that did not receive a local modification during the first conditioning C1. Thus, in this example, the second conditioning C2 may include applying a local modification D1 within the first wafer W1.

[0162] 8b, the second conditioning C2 may include applying multiple local modifications within a substrate that has already undergone a local modification with the first conditioning C1. Thus, in this example, the second conditioning C2 may include applying a local modification D2' within the second wafer W2. For example, the local modification D2' applied using the second conditioning C2 may not overlap with the local modification D2 applied using the first conditioning C1.

[0163] 9a-9c show experimental results of conditioning a substrate according to the present invention. Sub-figure 9a schematically illustrates a test wafer W and a corresponding coordinate system having an x-axis and a y-axis. Sub-figure 9b illustrates an optical image (IR microscope image) of multiple local modifications D (i.e., pixels D as described herein) applied within the test wafer. In the experiment, pixels D were applied within the test wafer W such that bending of the test wafer W occurred to substantially the same extent in the x- and y-directions. As described herein, pixels may be induced via focusing electromagnetic radiation within the test wafer W, and the optical properties of the electromagnetic radiation (e.g., at its focus) may be designed to adapt the local modification parameters of the pixels.

[0164] Subfigure 9c shows the results of a profilometry measurement of the surface of a test wafer W (having a diameter of 300 mm). The profilometry measurement shows the measured height along the x-axis of the test wafer W, indicated via height profile line X1. The profilometry measurement also shows the measured height along the y-axis of the test wafer W, indicated via height profile line Y1. Thus, height profile line X1 indicates the height distribution of the wafer relative to the outer wafer edge of the wafer at x=0 cm and x=30 cm. Height profile line Y1 indicates the height distribution of the wafer relative to the outer wafer edge of the wafer at y=0 cm and y=30 cm. Because the measurement probe scans the surface of the wafer and thus follows the outer shape of the wafer, the height profile lines X1, Y1 may indicate the shape of the test wafer along the corresponding axis.

[0165] It can be seen that substantial bending is induced in both directions, and that the bending is substantially the same along the two axes. Along height profile line X1, it can be seen that the center of the wafer (at x=15 cm) is located approximately 700 μm above the respective reference edges (at x=0 cm and x=30 cm). Along height profile line Y1, it can be seen that the center of the wafer (at y=15 cm) is located approximately 800 μm above the respective reference edges (at y=0 cm and y=30 cm).

[0166] Therefore, the measured test wafer W in subfigure 9c corresponds to a convex shape.

[0167] 10a-10c show further experimental results of substrate conditioning according to the present invention. In particular, in FIGS. 10a-10c, conditioning was applied to a test wafer having a diameter of 8 cm. FIGS. 10a-10c illustrate that multiple local modifications may be applied such that wafer bending occurs (substantially) along one direction. As can be seen in sub-FIG. 10a, the height profile line Y1 along the y-axis of the wafer indicates a large bending along the y-axis. However, the height profile line X1 along the x-axis of the wafer (orthogonal to the y-axis) indicates a relatively small bending along the x-axis. This may be achieved by inducing pixels in the wafer aligned along the x-axis. Such pixels are shown in sub-FIG. 10c. In particular, the pixels in sub-FIG. 10a are microstrain elements aligned along the x-axis. That is, it can be seen that the microstrain elements have an elongated shape with their major axis extending along the x-axis and their minor axis extending along the y-axis. Thus, such a microstrain element (of the plurality of microstrain elements) may have a first local force acting along the y-axis that is greater than a second local force of the microstrain element acting along the x-axis, and thus may induce greater bending along the y-axis than bending along the x-axis.

[0168] For illustrative purposes, sub-Figure 10b indicates how the elongated shape of the microstrain elements may be generated. For example, the microstrain elements may be induced by focusing electromagnetic radiation (e.g., from a laser) within the wafer. A corresponding apparatus (as described herein) may control the laser beam L accordingly. An aperture E may be present within the apparatus or may be adaptable to shape the laser beam L. In the example of Figure 10b, the aperture E may be a slit that may be controlled (adaptable) so that the long axis of its opening is oriented along the x-axis. The aperture E may therefore shape the output of the laser beam L such that the laser beam is focused into an elongated shape within the wafer (e.g., along the x-axis) such that the microstrain elements are oriented along the x-axis. In particular, various other mechanisms for inducing desired local modification parameters of the microstrain elements using an optical setup are possible (as described herein).

[0169] FIGS. 11a-11c show further experimental results of substrate conditioning according to the present invention. In particular, in FIGS. 10a-10c, conditioning was applied to a test wafer having a diameter of 8 cm. FIGS. 11a-11c illustrate (similarly to FIGS. 10a-10c) that multiple local modifications may be applied such that bending of the wafer occurs (substantially) along one direction. However, in FIGS. 11a-11c, the pixel was adapted such that bending occurs substantially along the x-axis of the wafer, as indicated by height profile line X1. In particular, FIG. 11c shows a pixel in which the microstrain element is aligned along the y-axis. Thus, such a microstrain element (of multiple microstrain elements) may have a first local force acting along the x-axis that is greater than a second local force of the microstrain element acting along the y-axis. Thus, a bending along the x-axis may be induced that is greater than a bending along the y-axis.

[0170] For illustrative purposes, FIG. 11b illustrates how the elongated shape of the microstrain elements may be generated to induce the pixels of FIG. 11c. As described for FIGS. 10a-10c, the apparatus for generating the pixels may include an aperture E for shaping a laser beam L focused into the wafer. In the example of FIG. 11b, aperture E may also be an (adaptable) slit, which may be controlled so that the long axis of its opening is oriented along the y-axis. Aperture E may therefore shape the output of laser beam L such that the laser beam is focused in an elongated shape into the wafer (e.g., along the y-axis) such that the microstrain elements are oriented along the y-axis. In particular, various other mechanisms for inducing desired local modification parameters of the microstrain elements using the optical setup are possible (as described herein).

[0171] 12 shows a first example of an apparatus 120 according to the invention. The apparatus may be configured to carry out the methods described herein. The main principle of the apparatus is that a laser beam is focused in a substrate in such a way that a local reaction is induced that results in a predefined local modification (i.e., pixel).

[0172] The apparatus 140 may include a laser unit L. The laser unit L may include a laser that may be controlled to output laser pulses along a laser beam direction. The laser may include a laser having a wavelength described herein. In particular, the laser may also include any other type of laser in the infrared range (having a wavelength between 700 nm and 50 μm).

[0173] In one example, the laser energy may include an energy of 1 μJ to 100 μJ. In one example, the laser power may include a power of 40 W to 200 W.

[0174] The apparatus 120 may further include a pixel modulator P. The pixel modulator P may include an acousto-optic modulator. The pixel modulator P may modulate whether an incident laser beam from a laser unit L is coupled into a main beam path of the apparatus. For example, the pixel modulator P may direct the incident laser beam so that it is not coupled into the main optical path of the apparatus. In one example, the pixel modulator P may induce blanking of the incident laser beam so that the laser beam is not coupled into the main beam path (e.g., via absorption of the laser beam light). The pixel modulator P enables control of whether a laser beam focus that induces a pixel in the substrate is applied within the substrate. The laser unit L and the pixel modulator P may be controlled via a laser control unit LC. The laser control unit LC may include a laser gate control unit.

[0175] Subsequently, optical elements along the main optical path of the laser are described that may be controlled in a deliberate manner to adapt the local modification parameters of pixels within the substrate.

[0176] In one example, the main optical path may comprise a deflecting mirror MR for deflecting the laser beam coming from the pixel modulator P (eg, for spatial design purposes).

[0177] The main path may further comprise a waveform manipulator W. The waveform manipulator W may be controllable to adapt the shape of the waveform of the laser beam wavefront. In one example, the waveform manipulator may be controllable to induce a desired astigmatism in the laser beam. For example, the waveform manipulator W may be controllable to induce astigmatism along a certain orientation. This may allow for adapting the orientation of the pixels (as described herein). The waveform manipulator W may comprise, for example, a spatial light modulator (SLM). The spatial light modulator may comprise a liquid crystal on silicon (LCoS SLM). In one example, the waveform manipulator W may comprise an optical unit that may adapt the waveform of the laser beam (e.g., by inducing a desired astigmatism). In one example, the waveform manipulator W may comprise a waveform control unit (which may comprise a motor for adapting the waveform manipulator).

[0178] The optical path may further include a relay unit R. The relay unit R may include two or more lenses. The relay unit R may be configured to function as a telescope. For example, the focal point of a first lens of the relay unit R may be located within the focal point of a second lens of the relay unit R.

[0179] The optical path may further include a multi-beam unit M. The multi-beam unit M may function to generate two or more partial beams from the incident laser beam. For example, the multi-beam unit M may include a diffractive optical element (DOE). The diffractive optical element may include a diffraction grating. The diffraction grating may include a transmissive and / or reflective grating. In one example, the multi-beam unit M may include a wavefront manipulator (e.g., a spatial light modulator). In one example, the multi-beam unit M and the wavefront manipulator W may be realized via a single optical element (e.g., a wavefront manipulator in the form of a spatial light modulator). In the example of FIG. 12, the multi-beam unit M is adapted to generate three spatially separated beams from the incident laser beam. Thus, one laser shot may generate three focal points within the substrate being processed (as indicated in FIG. 12). Similarly, a set of three pixels may be applied simultaneously within the substrate in this example. A shot may include one or more laser pulses coming from the laser unit L such that sufficient energy / power is applied within the substrate to generate at least one pixel. The multi-beam unit M may be configured to generate at least 4 partial beams in one shot (thus 4 pixels in one shot), at least 8 partial beams (thus 8 pixels in one shot), at least 10 partial beams (thus 10 pixels). It may also be conceivable to generate up to 100, 200, 300 and / or 500 pixels in one shot.

[0180] In another example, the multi-beam unit M may function to scan an incident laser beam onto predetermined scan positions within a substrate. For example, the multi-beam unit M may include a scanning unit (e.g., an acousto-optic deflector, an AOD, a spatial light modulator, a galvanometer scanner, etc.). To illustrate one example, the multi-beam unit may be configured to deflect the incident laser beam onto three predetermined scan positions within a substrate. This may be capable of inducing three local modifications within a spatial region / volume of the substrate within a scan window time. For example, the scanning unit may deflect the incident laser beam onto a first scan position. Subsequently, a first pixel may be written onto the first scan position. Thereafter, the scanning unit may deflect the incident laser beam to a second scan position. Subsequently, a second pixel may be written onto the second scan position. This is repeated for a third scan position. The scan window time may include the time during which the entire process for the first, second, and third scan positions occurs.

[0181] The optical path may further comprise a focusing unit O. The focusing unit O may include a telecentric lens unit. However, any other suitable optical system may be used as the focusing unit O. The focusing unit O may be movable (e.g., via a mechanical stage) to adapt the focusing depth of the laser beam. Thus, the focusing unit O may be used to focus the laser beam to a predetermined focusing depth within the substrate. The optical unit O may be configured such that the optical quality of the laser beam is minimized for a predetermined system focusing depth within the substrate (e.g., when no further compensation is made to the laser beam and / or its wavefront). For example, the optical quality may include a root-mean-square (RMS) wavefront error.

[0182] The optical path may further comprise a depth compensation unit D. The depth compensation unit D may be controllable to compensate for undesirable optical effects that may arise from focusing the laser beam to a focal depth different from a predetermined system focal depth. The depth compensation unit D may comprise a wavefront manipulator. The depth compensation unit D may comprise an optical medium. The optical medium may be positioned via an apparatus (e.g., along the optical axis of the main optical path) for depth compensation. In another example, the apparatus may control the refractive index of the optical medium.

[0183] In one example, the depth compensation unit D may be included in the wavefront manipulator W. The wavefront manipulator may therefore perform depth correction (e.g., via shaping the wavefront).

[0184] Furthermore, the apparatus 120 may comprise a height sensor H. The height sensor may measure the height from a reference point to the (top) surface of a substrate to be processed in the apparatus. The height may correspond to a distance parallel to the optical axis of the main optical path of the apparatus. For example, the height sensor may measure the distance between the focusing unit O and the (top) surface of the substrate. The apparatus may be configured to receive the height from the height sensor H and adapt the focusing of the laser beam accordingly.

[0185] Additionally, the apparatus 120 may include a stage S. The stage S may be configured to secure a (e.g., removable) chuck C. The chuck C may be configured to securely hold a substrate (e.g., a wafer). In another example, the chuck may be configured to securely hold a bonded pair of substrates (e.g., a bonded pair of wafers). In FIG. 12, a first wafer W1 is shown bonded to a second wafer W2, and the chuck C may securely hold the bonded pair of wafers. Chucking of a single wafer is also possible.

[0186] The chuck C may include an electrostatic chuck, a vacuum chuck, and / or a combination thereof. The chuck C may also include a non-contact chuck, a side-grip chuck (or a combination thereof). Furthermore, the chuck C may also be a transparent chuck. The stage S and the chuck C may be coupled such that they form a positioning unit. Thus, if the stage S moves, the chuck C moves accordingly (and / or vice versa). Furthermore, if the positioning unit moves, the substrate and / or bonded substrate pair secured by the chuck C will also move accordingly.

[0187] For example, the exemplary apparatus 120 may be configured to rotate the stage S such that the chuck C rotates to correspondingly enable rotational movement Sθ of the substrate and / or bonded substrate pair secured by the chuck C. For example, the stage S may comprise an R-theta stage. The R-theta stage may be configured for rotational speeds of 1000 rpm to 8000 rpm, preferably 2000 rpm to 6000 rpm, more preferably 2500 rpm to 5000 rpm, and most preferably 3000 rpm to 4000 rpm. This may enable high throughput when processing substrates according to the present invention.

[0188] Additionally, the exemplary apparatus 120 may be configured such that the positioning unit (comprising the stage S and chuck C) may move back and forth along a horizontal axis, which may enable lateral movement Sr of the substrate and / or bonded substrate pair secured by the chuck back and forth along the horizontal axis.

[0189] The rotational movement Sθ and lateral movement Sr may allow multiple local modifications to be applied in a spiral pattern within the substrate. The method as described herein may therefore be simply implemented via rotational movement (back and forth along one axis) and lateral movement of the substrate, which may reduce the complexity of the system.

[0190] The application of a spiral pattern, which is possible depending on the configuration of the positioning unit, is shown in the right subfigure of FIG. 12. An exemplary method is shown in which the apparatus 120 applies local corrections within a first wafer W1. As shown in one example, the apparatus 120 may simultaneously apply sets of three pixels (i.e., three local corrections D). Through a rotational movement Sθ, multiple sets of pixels may therefore be applied circumferentially along the radius of the first wafer W1. Through a lateral movement Sr, the radius at which the sets of pixels are applied may be changed. In particular, through a lateral movement Sr, the sets of pixels may be applied in a spiral pattern, as visualized in FIG. 12.

[0191] In particular, in one example, the positioning units (stage S and chuck C) of apparatus 120 may also be configured for lateral movement along two or more lateral axes (e.g., along the indicated x- and y-axes). In another example, the positioning units may also be configured for vertical movement (e.g., along the optical axis of the apparatus). Regardless of the configuration of the positioning units, the apparatus may be configured to actuate only the rotational and / or lateral movement functions to perform the application of the aforementioned spiral pattern. In other examples, the optical elements may also be movable to provide the aforementioned relative movement. For example, the objective lens may be moved laterally while the stage carrying the substrate or wafer rotates.

[0192] 13 shows a second example of an apparatus 130 according to the present invention. The apparatus may be configured to perform the methods described herein. Any aspects / features described for apparatus 120 (of the first example) may be applied to apparatus 130 of the second example. For example, apparatus 130 may include all the features described for apparatus 120.

[0193] However, in the illustrated example of apparatus 130 of FIG. 13 , the positioning unit, comprising stage S and chuck C, may be configured such that movement along two or more lateral axes may be induced on the substrate and / or pair of substrates. In one example, the positioning unit may be configured for lateral movement along an x-axis (Sx) and a y-axis (Sy), where the y-axis may be orthogonal to the x-axis. In the illustrated exemplary apparatus 130, the multi-beam unit M may be an optical element that functions to (simultaneously) generate three partial beams from an incident laser beam. (For example, the multi-beam unit M of apparatus 130 may include a beam splitter, e.g., a DOE.) Thus, the apparatus may be configured to simultaneously apply pixel sets PS of three pixels within the substrate.

[0194] By controlling the stage S along the x-axis and y-axis, multiple pixel sets PS may be arranged adjacent to one another (e.g., in a rectangular pattern) across a substrate (e.g., within a first wafer W1 as shown). The right sub-diagram of FIG. 13 shows the arrangement of various pixel sets PS, each with three pixels applied, on a first wafer W1. The pixel sets PS may be applied in a line-scan manner. For example, starting from the edge of the substrate, pixel sets may be applied in a line along the R1 direction (parallel to the x-axis) until the other end / edge of the substrate is reached. The stage may then be offset along the y-axis to allow for the generation of another pixel set in a line along the R2 direction (parallel to the x-axis). This may be repeated to generate pixels across the entire substrate.

[0195] In particular, any of the features described for device 140 may be included in device 130 of the first example.

[0196] 14 shows a third example of an apparatus 140 according to the present invention. The apparatus may be configured to perform the methods described herein. The optical setup of the apparatus may also comprise, similar to apparatus 130 and apparatus 140, a laser unit L, a pixel modulator P, a laser control unit LC, and a deflection mirror MR arranged in the optical path of the laser beam. Apparatus 140 may also comprise a stage S and a chuck C. Apparatus 140 may be configured to control stage S (and thus a substrate fixed on chuck C) as described for apparatus 130 (and / or apparatus 120).

[0197] However, the further optics and / or optical elements of the device 140 may be different.

[0198] For example, the main optical path of device 140 may comprise a beam expander E (as shown in FIG. 14). Beam expander E may comprise two lenses. The two lenses may be arranged such that the focal point of the first lens is located within the focal point of the second lens of the beam expander. The lenses may have additional optical properties or elements such that the incident laser beam is expanded (and preferably collimated) at the output of the beam expander.

[0199] The main optical path of the device 140 may further include a microlens array MLA. The incident (e.g., expanded) laser beam may be adapted by the microlens array MLA so that multiple focal points can be generated within a substrate positioned within the device. In the example of the device 140, the microlens array MLA includes a one-dimensional microlens array in which four microlenses are arranged along a line. However, the number of microlenses in the microlens array may not be limited by the present invention. In another example, the microlens array MLA includes a two-dimensional microlens array. This may therefore make it possible to simultaneously generate multiple focal points along a focal plane within the substrate.

[0200] In one example, the two-dimensional microlenses may be configured such that the quasi-focal points substantially cover the entire substrate. For example, the substrate may be processed in one shot (as all pixels illuminated on the substrate may be triggered simultaneously). In another example, the apparatus 140 may comprise a scanning unit for deflecting a laser beam onto one or more microlenses of the microlens array MLA. Thus, a subset of the possible focal points of the microlens array MLA may be generated in one shot.

[0201] The main optical path of the device 140 may further comprise a microlens coupling unit MO. For example, if the microlens array MLA constitutes a one-dimensional microlens array, the microlens coupling unit MO may comprise a Powell lens. The Powell lens may be configured to fan out the incident laser beam so that coupling of the incident laser beam into the one-dimensional microlens array may be facilitated.

[0202] For example, if the microlens array MLA is a two-dimensional microlens array, the microlens coupling unit MO may comprise a collimator lens, which may be configured such that the laser beam is coupled into the two-dimensional microlens array (or a subset of its microlenses) in a predefined manner.

[0203] In one example, device 140 may also include a wavefront manipulator W, a multi-beam generator M, and / or a depth compensation unit (as outlined for devices 120 and 130).

[0204] In particular, an apparatus according to the present invention may be configured such that the total writing time of pixels across the entire substrate is less than 30 seconds, preferably less than 20 seconds, more preferably less than 15 seconds, and most preferably less than 12 seconds, which may be made possible by the parallel processing techniques described herein, in which pixels may be generated simultaneously.

[0205] In one example, the devices described herein (and / or their focusing units O and / or microlens coupling units MO) may have a numerical aperture in the range of 0.35 to 0.85, or in the range of 0.55 to 0.85.

[0206] In particular, the apparatus according to the present invention may comprise a control unit (as described herein) to enable precise control of its components (e.g. optical elements) to carry out the methods described herein.

[0207] Further embodiments of the present invention are described below.

[0208] Example 1: A method for conditioning a bond of substrates, comprising: Applying a plurality of localized modifications within a first substrate to facilitate bonding of the first substrate to a second substrate A method comprising:

[0209] Example 2: The method of example 1, wherein applying the plurality of localized modifications in the first substrate is further based at least in part on properties of the second substrate and / or the first substrate.

[0210] Example 3: The method of example 1 or 2, wherein at least one substrate comprises one or more desired process structures.

[0211] Example 4: The method of any of Examples 1-3, wherein applying a plurality of local modifications into the first substrate is adapted to induce a first target geometry of the first substrate.

[0212] Example 5: The method of example 4, wherein the first target geometry is predetermined such that when the first substrate and the second substrate are bonded, at least one bond quality parameter is improved compared to when no conditioning occurs.

[0213] Example 6: The method of example 4 or 5, wherein the first target geometry is based at least in part on a predetermined geometry of a second substrate.

[0214] Example 7: The method of example 6, wherein the predetermined geometric shape of the second substrate comprises the overall geometric shape of the second substrate.

[0215] Example 8: The method of Example 7, wherein the overall geometry of the second substrate includes a surface topography and / or one or more deviations of the second substrate from a substrate reference plane.

[0216] Example 9: The method of any of Examples 1-8, further comprising applying a plurality of localized modifications in the second substrate.

[0217] Example 10: The method of example 9, wherein applying the plurality of localized modifications into the second substrate is adapted to induce a second target geometry of the second substrate.

[0218] Example 11: The method of Example 10, wherein the second target geometry is predetermined such that when the first substrate and the second substrate are bonded, at least one bond quality parameter is improved compared to when no conditioning occurs.

[0219] Example 12: The method of Example 10 or 11, with any of Examples 3-7, wherein the second target geometry is based at least in part on the first target geometry, or vice versa.

[0220] Example 13: A method as described in any of Examples 4 to 12, further comprising transmitting the target geometric shape of at least one of the substrates to a device for further processing of at least one of the substrates, in particular a bonding device for bonding the first substrate and the second substrate.

[0221] Example 14: The method of any of Examples 1-13, wherein applying a plurality of local modifications within the first substrate and / or the second substrate is adapted such that when the first substrate and the second substrate are placed in a bonding position, at least one local bonding area of ​​the first substrate and a corresponding local bonding area of ​​the second substrate have substantially the same curvature.

[0222] Example 15: The method of any of Examples 1-14, wherein applying the plurality of localized modifications in the first substrate and / or the second substrate is adapted such that structures of the first substrate are substantially aligned with corresponding structures of the second substrate when the first substrate and the second substrate are placed in a bonding position.

[0223] Example 16: The method of any of Examples 1 to 15, wherein applying a plurality of local modifications within the first substrate is adapted to induce positional correction of at least one structure of the first substrate.

[0224] Example 17: The method of any of Examples 1-16, wherein applying a plurality of localized modifications comprises applying one or more pulses of electromagnetic radiation to a corresponding substrate to produce a corresponding plurality of localized modifications in the substrate.

[0225] Example 18: The method of any of Examples 1 to 17, wherein conditioning is performed before bonding of the first substrate to the second substrate occurs.

[0226] Example 19: The method of any of Examples 1 to 18, wherein conditioning is performed after bonding of the first substrate and the second substrate has occurred.

[0227] Example 20: The method of any of Examples 1-19, further comprising bonding the first substrate and the second substrate.

[0228] Example 21: A method for conditioning a first substrate, comprising: receiving a second characteristic of the second substrate; Determining a plurality of local modifications to be applied within the first substrate based at least in part on the second characteristic. A method comprising:

[0229] Example 22: Receiving a first characteristic of a first substrate; determining, based at least in part on the first characteristic and the second characteristic, a plurality of localized modifications to be applied within the first substrate to facilitate bonding between the first substrate and the second substrate; 22. The method of Example 21, further comprising:

[0230] Example 23: A method for manufacturing a semiconductor device, further comprising: deriving a first target geometric shape of the first substrate to facilitate bonding of the first substrate and the second substrate; 23. The method of example 21 or 22, wherein the plurality of local modifications applied in the first substrate are determined to induce a first target geometry for the first substrate.

[0231] Example 24: The method further includes deriving a second target geometric shape of the second substrate to facilitate bonding of the first substrate and the second substrate; 24. The method of any of Examples 21-23, wherein the plurality of local modifications applied in the second substrate are determined to induce a second target geometry for the second substrate.

[0232] Example 25: A computer program comprising instructions for carrying out the method according to any one of Examples 1 to 24 when the computer program is executed.

[0233] Example 26: An apparatus for conditioning a bond of substrates, comprising: means for applying a plurality of localized modifications within the first substrate to facilitate bonding of the first substrate to the second substrate; A control unit configured to control an apparatus to carry out the method according to any one of Examples 1 to 24. An apparatus comprising:

[0234] Example 27: The apparatus of Example 26, wherein the control unit is configured to receive information that the first substrate is to be bonded to the second substrate and to control the apparatus to perform the method based at least in part on the information.

[0235] Example 28: Means for applying a source for generating one or more pulses of electromagnetic radiation; a first element for focusing a beam of electromagnetic radiation to a predetermined focal depth within a first substrate; 28. The device of Example 26 or 27, comprising:

[0236] Example 29: An apparatus described in any of Examples 26 to 28, wherein the apparatus further comprises means for positioning the first substrate to control a local position of at least one local modification of the plurality of local modifications, and the positioning comprises rotating the first substrate.

[0237] Example 30: The apparatus of example 29, wherein the means for positioning is configured to position a pair of bonded substrates comprising a first substrate bonded to a second substrate.

[0238] Example 31: An apparatus for conditioning a first substrate, comprising: means for receiving a second characteristic of the second substrate; means for determining a plurality of local modifications to be applied within the first substrate based at least in part on the second characteristic; An apparatus comprising:

[0239] Example 32: The device according to any one of Examples 26 to 31, further comprising a memory for storing the computer program according to Example 25.

Claims

1. 1. A method for conditioning a bond of a substrate, comprising: Applying a plurality of localized modifications within a first substrate to facilitate bonding of the first substrate to a second substrate. A method comprising:

2. The method of claim 1 , wherein the application of the plurality of local modifications within the first substrate is further based at least in part on properties of the second substrate and / or of the first substrate.

3. The method of claim 1 or 2, wherein the first substrate and / or the second substrate comprises one or more desired process structures.

4. The method of any of claims 1 to 3, wherein the application of the plurality of local modifications into the first substrate is adapted to induce a first target geometry of the first substrate.

5. 5. The method of claim 4, wherein the first target geometry is predetermined such that when the first substrate and the second substrate are bonded together, at least one bond quality parameter is improved compared to when no conditioning occurs.

6. The method of claim 4 or 5, wherein the first target geometry is based at least in part on a predetermined geometry of the second substrate.

7. The method of claim 6 , wherein the predetermined geometric shape of the second substrate comprises the overall geometric shape of the second substrate.

8. The method of claim 7 , wherein the overall geometry of the second substrate includes a surface topography and / or one or more deviations of the second substrate from a substrate reference plane.

9. The method of any preceding claim, further comprising applying a plurality of local modifications in the second substrate.

10. The method of claim 9 , wherein the application of the plurality of local modifications into the second substrate is adapted to induce a second target geometry of the second substrate.

11. 11. The method of claim 10, wherein the second target geometry is predetermined such that when the first substrate and the second substrate are bonded together, at least one bond quality parameter is improved compared to when no conditioning occurs.

12. The method of claim 10 or 11 when dependent on any of claims 3 to 7, wherein the second target geometry is based at least in part on the first target geometry, or vice versa.

13. The method according to any of claims 4 to 12, further comprising transmitting the target geometric shape of at least one of the substrates to a device for further processing of at least one of the substrates, in particular a bonding device for bonding a first substrate and a second substrate.

14. 14. The method of any of claims 1 to 13, wherein the applying of the plurality of local modifications in the first substrate and / or the second substrate is adapted such that when the first substrate and the second substrate are placed in a bonding position, at least one local bonding area of ​​the first substrate and a corresponding local bonding area of ​​the second substrate have substantially the same curvature.

15. 15. The method of any of claims 1 to 14, wherein the applying of the plurality of localized modifications in the first substrate and / or the second substrate is adapted such that structures of the first substrate are substantially aligned with corresponding structures of the second substrate when the first and second substrates are placed in a bonding position.

16. The method of any of claims 1 to 15, wherein said applying said plurality of local modifications in said first substrate is adapted to induce positional corrections of at least one structure of said first substrate.

17. 17. The method of any preceding claim, wherein said applying said plurality of localized modifications comprises applying one or more pulses of electromagnetic radiation to corresponding said substrate to cause corresponding said plurality of localized modifications in said substrate.

18. The method of any of claims 1 to 17, wherein the conditioning is performed before the bonding of the first substrate and the second substrate occurs.

19. The method of any of claims 1 to 18, wherein the conditioning is performed after the bonding of the first substrate and the second substrate has occurred.

20. The method of any preceding claim, further comprising bonding the first substrate and the second substrate together.

21. 1. A method for conditioning a first substrate, comprising: receiving a second characteristic of the second substrate; determining a plurality of local modifications to be applied within the first substrate based at least in part on the second characteristic; A method comprising:

22. receiving a first characteristic of the first substrate; determining the plurality of localized modifications to be applied within the first substrate to facilitate bonding between the first substrate and the second substrate based at least in part on the first characteristic and the second characteristic; 22. The method of claim 21 further comprising:

23. deriving a first target geometric shape of the first substrate to facilitate bonding of the first substrate and the second substrate; 23. The method of claim 21 or 22, wherein the plurality of local modifications applied in the first substrate are determined to induce the first target geometry for the first substrate.

24. deriving a second target geometric shape for the second substrate to facilitate bonding of the first substrate and the second substrate; The method of any of claims 21 to 23, wherein the plurality of local modifications applied in the second substrate are determined to induce the second target geometry for the second substrate.

25. A computer program comprising instructions for performing the method according to any of claims 1 to 24 when the computer program is executed.

26. 1. An apparatus for conditioning a bond of a substrate, comprising: means for applying a plurality of localized modifications within a first substrate to facilitate bonding of said first substrate to a second substrate; A control unit configured to control the device to perform the method according to any of claims 1 to 24. An apparatus comprising:

27. 27. The apparatus of claim 26, wherein the control unit is configured to receive information that the first substrate is to be bonded to the second substrate and to control the apparatus to perform the method based at least in part on the information.

28. The means for applying comprises: a source for generating one or more pulses of electromagnetic radiation; a first element for focusing the beam of electromagnetic radiation to a predetermined focal depth within the first substrate; 28. The apparatus of claim 26 or 27, comprising:

29. 29. The apparatus of claim 26, further comprising means for positioning the first substrate to control a local position of at least one local modification of the plurality of local modifications, the positioning comprising rotating the first substrate.

30. 30. The apparatus of claim 29, wherein the means for positioning is configured to position a bonded substrate pair comprising the first substrate bonded to the second substrate.

31. 1. An apparatus for conditioning a first substrate, comprising: means for receiving a second characteristic of the second substrate; means for determining a plurality of local modifications to be applied within the first substrate based at least in part on the second characteristic; An apparatus comprising:

32. An apparatus according to any one of claims 26 to 31, further comprising a memory for storing the computer program according to claim 25.

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