Substrate holder and method for fixing and bonding substrates

Abstract

To provide a substrate holder for fixing an asymmetrically deformed substrate, and a method for fixing and joining the substrate.SOLUTION: The substrate holder 1 for housing a substrate (13) includes fixing elements 6 and 6' for fixing the substrate, and the fixing elements 6 and 6' can be grouped into zones 7 and 7'.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a substrate holder and a method for securing and bonding substrates.

[0002] The prior art contains publications that disclose methods for optimally bonding substrates together, in particular WO 2017162272, which shows a substrate holder with individual zones, as well as WO 2013023708, WO 2012083978 and WO 2018028801.

[0003] Asymmetrically deformed substrates have been a major problem in the prior art. Many substrates exhibit mechanical anisotropy, i.e., their elastic modulus is significantly directionally dependent. This directional dependence of the elastic modulus also leads to directional dependence of other mechanical properties, particularly ductility. When such substrates are subjected to forces, particularly gravity, asymmetric deformation occurs. This asymmetric deformation also exists during the contact and / or bonding process of two substrates, inevitably resulting in asymmetric propagation of the bonding wavefront and thus in undesirable runout effects.

[0004] In the semiconductor industry, substrates have been bonded together for many years using so-called bonding processes. Before bonding, these substrates must be aligned as precisely as possible, and deviations in the nanometer range are problematic. The alignment of the substrates is typically achieved using alignment marks. Apart from the alignment marks, other elements, particularly functional elements, are also present on the substrates, which also need to be aligned with one another during the bonding process. The alignment accuracy between these individual functional elements is required across the entire substrate surface. Therefore, for example, a very good alignment accuracy in the center of the substrate cannot be satisfactory if it decreases toward the edge.

[0005] In the prior art, as already mentioned above, there are numerous methods and systems that can attempt to influence the joining process, such as for example WO 2017162272, EP 2656378 or WO 2014191033.

[0006] One of the biggest challenges in bonding is the period during which the two substrates are independently bonded together. This is the period from the start of bonding until the contact surfaces of the substrates are fully in contact. During this period, the alignment of the two substrates can still change significantly compared to the previous alignment. Once the two substrate surfaces are bonded together, separation is theoretically possible, but it is expensive, has low throughput, and is prone to defects.

[0007] SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for bonding two substrates which overcomes the problems of the prior art and improves bonding accuracy, particularly at the edges of the substrates.

[0008] The problem of the present invention is solved by the features of the independent claims. Advantageous developments of the invention are presented in the dependent claims. All combinations of at least two features shown in the description, claims and / or drawings are also within the scope of the present invention. In the stated value ranges, values ​​inside the stated limits are also considered to be disclosed as limit values ​​and can be claimed in any combination.

[0009] The present invention relates to a substrate holder for accommodating substrates, the substrate holder comprising fixing elements for fixing the substrates, the fixing elements being groupable into zones, the zones being preferably arranged in an annular shape, more preferably in a circular shape.

[0010] Here, a zone is any amount of fixed elements, regardless of whether the fixed elements are spatially adjacent or located in opposing edge regions. Because a zone is a certain number of fixed elements, the definition or configuration of a zone may change over time.

[0011] In the following text of this specification, reference is made to the shape or position of a zone. This refers to the shape and position of the envelope that surrounds all fixed elements within such a zone. When reference is made to the switching ability of a zone, this refers to the switching ability of all fixed elements within that zone. In particular, turning off a zone means turning off all fixed elements within the zone. This does not affect the possibility, and preferably all fixed elements within a zone can also be switched individually. In the extreme case, a zone may have only one fixed element.

[0012] Preferably, all the fixing elements of the same zone can be controlled by a single control element, in particular by a control valve when vacuum fixing elements are used, and thus advantageously all the fixing elements of one zone can be switched on simultaneously.

[0013] In order to advantageously and targetedly deform the advancing bonding wave, different fastening elements or zones can be switched on and off, in particular with a time lag.

[0014] The invention further relates to a method for fastening and bonding one or more substrates, in particular by means of a substrate holder according to the invention, in which the fastening elements are grouped into zones, the zones being preferably arranged in an annular, more preferably in a circular ring.

[0015] The annular arrangement advantageously allows the substrates to be optimally clamped and released during the bonding process, in particular minimizing "runout" errors and thus significantly increasing bonding accuracy. The preferred annular arrangement allows clamping and release in an even more favorable manner, since the bonding wave typically propagates in an annular direction as well.

[0016] Preferably, a substrate holder is provided in which the zones are arranged symmetrically relative to the center of the substrate holder, which advantageously achieves a further increase in bonding accuracy, since the bonding wave typically propagates symmetrically relative to the center of the substrate holder.

[0017] Preferably, the substrate holder is further provided in which the zones are arranged in a number of rings, preferably in a circular ring, around the center of the substrate holder, which advantageously also allows for optimal release in the radial direction of the substrate holder.

[0018] Preferably, a substrate holder is further provided in which the zones are uniformly spaced apart in the radial and / or azimuth direction, which advantageously allows for particularly precise release control.

[0019] Preferably, furthermore, a substrate holder is provided in which each zone is configured to vary in width, in particular to increase in width, from the center of the substrate holder towards the edge of the substrate holder, which may be necessary to obtain better bonding results, since the speed at which the bonding wave propagates may also vary as a function of distance from the center.

[0020] Preferably, furthermore, a substrate holder is provided in which each zone is individually switchable, which advantageously allows flexible control of these zones depending on the desired release.

[0021] Preferably further, a substrate holder is provided in which multiple zones can be grouped and switched together, which advantageously allows a larger area to be switched as required, allowing for more flexible and precise release.

[0022] Preferably, furthermore, a substrate holder is provided in which the number of fixing elements in each zone is flexibly changeable, which advantageously allows for precise control of the release, for example by increasing or decreasing the attractive force in individual zones.

[0023] Preferably, a substrate holder is further provided in which the fixing elements can be flexibly allocated to the different zones. Alternatively or additionally, the fixing elements can be controlled across the zones. Advantageously, therefore, the holding force in each zone can be flexibly adjusted as required.

[0024] The present invention describes in particular an apparatus and a method for bonding two substrates with a minimum runout, where the invention is based in particular on the idea of ​​using at least one substrate holder with specially configured zones consisting of a plurality of fixing elements for fixing asymmetrically deformed substrates, whereby the specially configured zones and their fixing elements, and in particular the inventive switching of these zones or their fixing elements, allow the asymmetric deformation of the substrates to be compensated, in particular even while the bonding process is still taking place, resulting in an optimal bonding wavefront and thus an optimal bond.

[0025] It is generally unknown which substrate to fix to the substrate holder, what mechanical anisotropy the substrate has, or how much the substrate will be distorted when fixed. Furthermore, substrates of different thicknesses generally deform differently due to gravity when fixed to the upper substrate holder. Therefore, it is impossible to create a new substrate holder that can accommodate every possible form of asymmetry.

[0026] The substrate holder according to the invention advantageously allows, in particular, asymmetrically deformed substrates to be compensated for by a targeted switching technique of zones, thereby compensating for the asymmetry, in particular while the bonding process is still taking place. Advantageously, therefore, only one type of substrate holder needs to be designed, which can be used for different substrates with different degrees of asymmetric deformation.

[0027] The present invention is based on the idea of ​​providing a substrate holder with specially formed zones, the shape, placement, and control of which improve the bonding result. As already described in detail in WO2017162272, the adjustment of the substrate curvature is crucial for the success of the defect-free bonding process. Therefore, the present invention particularly describes a very special substrate holder whose development has been completed in the past few months and years. In particular, reference is also made to the process steps already disclosed in WO2017162272.

[0028] The substrate holder according to the invention is primarily used as an upper substrate holder, but can also be satisfactorily used below the joining system for fixing a lower substrate. In particular, one substrate holder according to the invention can be used as an upper substrate holder and one substrate holder according to the invention can be used as a lower substrate holder, respectively. The targeted adjustment of the curvature, which is dealt with in detail and disclosed in WO2017162272, is further improved by the novel substrate holder design according to the invention.

[0029] A change in curvature is understood in particular to mean a deviation of the substrate from its initial state (in particular the curvature set before contact). According to the invention, bonding is controlled in particular by managing the control of the fixation of the substrates after contact of the contact surfaces. Corresponding fixation means are in particular provided by the device.

[0030] A further and particularly unique aspect of the present invention resides in the use of fixing elements, in particular individually switchable and grouped into specially formed zones, by means of which the advance of the bonding wave between the contact surfaces can be controlled or adjusted in a managed manner. The shapes of the disclosed zones are very specific, resulting in important differences compared to WO2017162272.

[0031] A zone generally comprises at least one fixation element, but in particular a plurality of fixation elements, which are individually controllable.

[0032] The underlying idea here is to manage, control, or adjust the curvature and / or the clamping and / or release of at least one of the two substrates in a targeted manner, thereby managing, controlling, or adjusting the advancing bond wave, so as to bring the two substrates into contact optimally and continuously, especially from the inside to the outside, along the contact surface. This method according to the invention is intended to compensate for asymmetries, especially mechanical asymmetries, of the substrates present before and / or during bonding, so that the bond wave has a desired, especially radially symmetrical, shape. According to the invention, this effect is achieved by specially formed zones and the inventive control of the clamping elements of these zones. Optimal contact is understood to mean, in particular, that the "runout" error is minimized or, in optimal cases, even eliminated at all points of the contact interface between the two substrates.

[0033] In general, the substrate holder according to the invention allows for a direction-dependent influence on the advance of the bonding wave. In particular, the substrate holder according to the invention allows for the generation of radially symmetric, i.e. circularly propagating, bonding wavefronts. Thus, a substrate held by the substrate holder according to the invention can be deformed anisotropically in a targeted manner by controlling the individual, specially formed zones.

[0034] Depending on whether the substrate holder according to the invention is used on the top or bottom side, different effects are produced on the substrates clamped therewith. The biggest difference between the two substrates is the direction of the action of gravity during the bonding process. For the substrate clamped on the top side, gravity generally causes anisotropic sagging after activation and / or passivation of at least some zones. This is not the case for the substrate clamped on the bottom side.

[0035] Sensor Preferably, a sensor for monitoring the distance between the substrate and the substrate holder is integrated into the substrate holder according to the invention. This sensor allows the propagation speed and, in particular, the symmetrical shape of the bonding wave to be monitored during the bonding process and, if necessary, adaptively adjusted. If this extended function according to the invention is integrated into both substrate holders, both substrates can be measured simultaneously and, in particular, adapted to minimize their runout errors while the bonding process is still taking place. Here, this adaptation is achieved, in particular, by switching between different specially designed zones in a targeted manner.

[0036] Fixed elements Any of the clamping elements mentioned according to the invention can be switched individually, i.e. into a clamped or unclamped state, and in particular the pressing force of the substrate against the clamping element can also be adjusted in a targeted manner, so that the normal force or normal stress can be determined.

[0037] The fixing elements may be separated from one another by sealing elements. However, in a particularly preferred embodiment according to the invention, the fixing elements are recessed, in particular milled, into the substrate holder surface. This embodiment is particularly suitable when vacuum fixing elements are used. In an expanded form according to the invention, small protrusions, studs, pins or webs are present in the recesses, the surface of which coincides with the substrate holder surface.

[0038] The individual fixing elements within one zone (e.g., circle segments of the same radius) can be flexibly controlled, so that, for example, the substrate can be fixed along almost the entire circumference during the loading process, ensuring that the substrate is as flat as possible at this point. Then, during the bonding process itself, multiple fixing elements can be deactivated along the same radius.

[0039] It is also possible to turn off the locking characteristics of the locking elements in one zone simultaneously or with a predetermined delay, allowing for finer control of the bonding speed. In particular, if a radially asymmetric advance of the bond wavefront is being measured, individual locking elements can be switched on until the bond wavefront becomes radially symmetric again.

[0040] If the fixing element is designed as a vacuum fixing element, the pressure present in the vacuum fixing part is 0.01 mbar to 1000 mbar, preferably 0.01 mbar to 800 mbar, even more preferably 0.01 mbar to 500 mbar, very preferably 0.01 mbar to 100 mbar, and most preferably 0.01 mbar to 10 mbar. The pressure difference between the relatively high pressure on the outside and the relatively low pressure on the inside of the vacuum fixing element acts as a pressing force on the substrate, leading to fixing of the substrate.

[0041] zone The individual fixed elements can be grouped into zones.

[0042] In a first embodiment according to the invention, the zones are present only at the periphery of the substrate holder, with radial and / or azimuthal separation between the zones, in particular with radial and azimuthal separation.

[0043] The zones are preferably arranged symmetrically about the axis of rotation with n-fold symmetry, where n is greater than 1, preferably greater than 4, even more preferably greater than 6, very preferably greater than 12, and most preferably greater than 24. The larger the step size of the axis of rotation, the more zones there are along the circumference but fewer zones along the azimuthal angle. The optimal number of zones per circumference and along the radial direction is determined, inter alia, by empirical measurements and / or simulations.

[0044] In a first embodiment of the invention, several zones, in particular consisting of several fastening elements, are present around the periphery of the substrate holder, and one large central zone, in particular consisting of only one fastening element, which occupies the majority of the substrate surface and serves to strongly fasten the substrate, while the peripheral zone of the substrate holder serves to finely control, in particular to specifically influence the shape of the bond wave.

[0045] In a second embodiment according to the invention, the substrate holder is composed exclusively of zones, in particular at the periphery, of fixing elements, while the largest area-wise part of the substrate holder is free of zones.

[0046] In a third embodiment according to the invention, the substrate holder is composed exclusively of a zone, in particular located on the periphery, consisting of a plurality of fastening elements and a single zone, in particular closed all around, consisting of at least one, preferably exactly one, fastening element.

[0047] In a fourth embodiment according to the invention, the substrate is fixed at its outer edge by a completely circumferential, in particular closed, most preferably annular, zone consisting of at least one fixing element, the zone lying inside the outer zone being switchable, thereby deforming the substrate. This is particularly possible if the fixing function of the individual fixing elements is based on vacuum suction or fluid flushing means.

[0048] In a fifth embodiment according to the invention, at least some of the zones are formed to surround or at least be aligned with other zones.

[0049] The zones and / or fixing elements may be arranged in particular in the following configurations: 1. Circular 2. Spiral 3. Grid 4. Radial 5. Combinations of the above (especially radially connected rings).

[0050] Loading Pin If the substrate holder has a loading pin, there will always be a hole in the substrate holder surface. When switching zones with a vacuum fixture, it may be necessary to take measures for sealing purposes. Due to this hole through which the loading pin moves, there are several variations in the application of overpressure in the zone.

[0051] In the first variation, the hole is simply left open (optimizing the embodiment for small leakage) and the overpressure must be maintained by a corresponding continuous flow of fluid in the region between the substrate and the substrate holder (balance of inflow and outflow).

[0052] In a second variant, the loading pin is provided with a seal, which makes it possible to build up a static overpressure in the closed area between the wafer and the holding device.

[0053] When the substrate holder according to the present invention is configured as an upper substrate holder, the loading pin may be a pin with a hole, tube, or other fluid system therein, which generates a vacuum on the surface of the loading pin, allowing the loaded substrate to be secured and lifted against the direction of gravity. Thus, the loading pin pulls the secured substrate upward during loading, and ultimately contacts and secures it to the surface of the substrate holder.

[0054] Hollowed out part The substrate holder according to the invention has a passage or cutout, which may in particular be glazed, so that the rear side of the fixed substrate can be seen. The passage can be preferably closed by a lid, in particular automatically.

[0055] Deformation elements A further, particularly original, idea that can be combined with the above-mentioned invention is the use of deformation elements as bending and / or curvature-changing means, which are in particular constituted by gas release openings, thereby preventing mechanical contact with the substrate. The control of the curvature is made even more precise by the combination of the above-mentioned features.

[0056] Any of the described embodiments according to the invention can have deformation elements for deforming the clamped substrate. In particular, if the individual zones have vacuum clamping elements, the individual zones can use fluids for deforming the substrate.

[0057] If the deformation element operates with a fluid, the pressure of the fluid is between 0.1 bar and 10 bar, preferably between 0.2 bar and 8 bar, even more preferably between 0.3 bar and 7 bar, very preferably between 0.4 bar and 6 bar, most preferably between 0.5 bar and 5 bar.

[0058] The force applied by the deformation element to the substrate is between 0.1N and 1000N, preferably between 0.2N and 500N, even more preferably between 0.3N and 250N, very preferably between 0.4N and 200N, and most preferably between 0.5N and 100N.

[0059] Bond wave monitoring To determine the propagation speed of the bonding wavefront in a direction-dependent manner, a sensor can be integrated into the substrate holder, which makes it possible to measure the distance between the substrate holder surface and the loaded substrate at any given time: 1. A plurality of radial sensors, in particular radial sensors passing through the centers of the individual zones, for determining the velocity as a function of the distance to the center; 2. Multiple sensors placed along radii, located between the radii mentioned in point 1, allowing for determination of velocities in different directions.

[0060] The propagation of the bond wave can be monitored using existing sensors capable of measuring the distance between the substrate and the substrate holder surface. Each sensor has a starting value before the start of the bonding process. This starting value is, for example, zero if the substrate in the sensor's area is in contact with the substrate holder surface. If the substrate is not fully fixed, for example, if it sags locally or is locally curved, the starting value will be greater than zero. Each sensor obtains an end value, particularly after the bonding process is completed. The corresponding change in the sensor value allows one to deduce from this whether the substrate has been bonded in the area of ​​the respective sensor. In this way, the progression of the bond wave position as a function of time is obtained. Depending on the precise positioning of the sensors, it is also possible to obtain data on the bond wave position in different directions as a function of time.

[0061] method Bond measurement method A first preferred method according to the present invention, which allows measuring and matching the bonding wavefronts of two substrates to be bonded, is as follows.

[0062] In a first process step, a first substrate is fixed to a first, in particular inventive, substrate holder.

[0063] In a second process step, a second substrate is fixed to a second, in particular inventive, substrate holder.

[0064] In a third process step, the values ​​of sensors measuring the backside of the substrate of the first and / or second substrate are checked and / or set to zero, in particular the sensors are distance sensors.

[0065] In a fourth process step according to the invention, the two substrates are brought closer together until there is a desired distance between the substrate surfaces that are to be joined together.

[0066] In a fifth process step according to the invention, the upper and / or lower substrate is deformed using the deformation element already described, so that the two substrates come into contact at least at one point, in particular exactly at one point. In particular, since the measurement of the backside of the substrates using the sensor is already performed during deformation of the upper and / or lower substrate, the curvature of the upper and / or lower substrate is already known very accurately before and / or during contact. This makes it possible to detect any asymmetries in the deflection.

[0067] In the sixth process step according to the invention, the precise release of the first and / or second substrates, brought about by the specifically targeted and controlled individual switching of the fastening elements of the individual zones, ensures the desired progression of the bond wavefront in time. In particular, it is desirable for the bond wavefront between the two substrates to have a radially symmetric shape at all times. During the propagation of the bond wavefront, sensors continuously measure the backside of the first and / or second substrates, so that in the event of undesired deviations of the bond wavefront, the individual fastening elements of the zones can be specifically controlled to restore the bond wavefront to its desired shape.

[0068] An alternative second preferred method according to the present invention performs the fourth and fifth process steps of the first method according to the present invention in reverse order. First, the first and / or second substrates are deformed without contacting each other. Then, the two substrates are brought relatively close together until they come into contact. In particular, the relative translational movement of the two substrates to bring the two substrates closer together is terminated immediately after they come into contact.

[0069] In one particular embodiment of the method according to the invention, the lower substrate is always fixed over its entire surface and is therefore not curved.

[0070] Apart from the bond wave measurement method according to the invention, there are also bond wave manipulation methods according to the invention, which can be combined with the previously described bond wave measurement method, especially in process step 6. These methods according to the invention are very specific and rely in particular on the substrate holder with the special zones according to the invention, which will now be described in detail.

[0071] The first bond wave operating method according to the invention also particularly further comprises the following process steps: First joining method In a first process step according to the invention, the lower substrate is fixed over its entire surface, ie, not curved.

[0072] In the second process step of the present invention, the upper substrate is fixed to a substrate holder having multiple zones, particularly zones that exist only on the periphery of the substrate holder. Preferably, there are enough zones to allow for 2n-fold symmetry. Particularly preferably, the substrate holders each have eight peripheral zones. In this case, for example, four zones exist at 0°, 90°, 180°, and 270°, hereinafter referred to as normal positions. The remaining four particularly long zones exist between them, i.e., at 45°, 135°, 225°, and 315°, hereinafter referred to as diagonal positions. Initially, all 2n zones are in a switching state, and fixing the upper substrate securely fixes the upper substrate, thereby at least minimizing the effects of gravity-induced deflection.

[0073] In a third process step according to the invention, n out of 2n zones are passivated, in particular the long diagonal zones. The passivation of the n zones preferably deforms the substrates to compensate for mechanical anisotropies and gravitational asymmetries, so that the bonding wavefront obtains the desired shape, in particular a radially symmetric shape, during the bonding process.

[0074] In a fourth process step according to the invention, the contacting of the substrates is carried out, in particular by means of deformation means and / or by bringing the substrate holders closer together relative to one another.

[0075] In a fifth process step according to the invention, measurements are taken of the backside of the substrate holder of the first and / or second substrate and the propagating bonded wavefront is appropriately adapted by appropriately switching the fixing elements of the individual zones as required.

[0076] Second joining method The second bond wave operating method according to the invention in particular further comprises the following process steps: In the first process step of the present invention, the lower substrate is fixed to a substrate holder having multiple zones, particularly zones that exist only on the periphery of the substrate holder. Preferably, there are enough zones to allow for 2n-fold symmetry. Particularly preferably, the substrate holders each have eight peripheral zones. In this case, for example, four zones exist at 0°, 90°, 180°, and 270°, hereinafter referred to as normal positions. The remaining four particularly long zones exist between them, i.e., at 45°, 135°, 225°, and 315°, hereinafter referred to as diagonal positions. Initially, all 2n zones are in a switching state, fixing the lower substrate.

[0077] In the second process step of the present invention, the upper substrate is fixed to a substrate holder having multiple zones, particularly zones that exist only on the periphery of the substrate holder. Preferably, there are enough zones to allow for 2n-fold symmetry. Particularly preferably, the substrate holders each have eight peripheral zones. In this case, for example, four zones exist at 0°, 90°, 180°, and 270°, hereinafter referred to as normal positions. The remaining four particularly long zones exist between them, i.e., at 45°, 135°, 225°, and 315°, hereinafter referred to as diagonal positions. Initially, all 2n zones are in a switching state, and fixing the upper substrate securely fixes the upper substrate, thereby at least minimizing the effects of gravity-induced deflection.

[0078] In a third process step according to the invention, the diagonal zones are passivated.

[0079] In a fourth process step according to the invention, the contacting of the substrates is carried out, in particular by means of deformation means and / or by bringing the substrate holders closer together relative to one another.

[0080] In a fifth process step according to the invention, measurements are taken of the backside of the substrate holder of the first and / or second substrate and the propagating bonded wavefront is appropriately adapted by appropriately switching the fixing elements of the individual zones as required.

[0081] The distance between approaching substrates is 0 μm to 2000 μm, preferably 0 μm to 1500 μm, more preferably 0 μm to 1000 μm, and most preferably 0 μm to 500 μm.

[0082] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. [Brief explanation of the drawings]

[0083] [Figure 1] 1 shows a substrate holder according to the invention in a first embodiment according to the invention; [Figure 2] 1 shows a substrate holder according to the invention in a second embodiment according to the invention; [Figure 3] 10 shows a substrate holder according to the invention in a third embodiment according to the invention; FIG. [Figure 4] 10 shows a simplified representation of a substrate holder according to the invention in a fourth embodiment according to the invention; FIG. [Figure 5] 10 shows a simplified representation of a substrate holder according to the invention in a fifth embodiment according to the invention; FIG. [Figure 6] FIG. 10 shows a simplified representation of a substrate holder according to the invention in a sixth embodiment according to the invention. [Figure 7] 5 shows a simplified representation of the substrate holder according to the invention according to FIG. 4 with a fixed substrate;

[0084] In the figures, identical components or components having identical functions are designated by the same reference numerals.

[0085] All shown figures are schematic representations of the substrate surface with its zones and fixing elements, which are not necessarily to scale. A complete depiction of the substrate holder with all its components has been intentionally omitted, as this would not add any value to the idea according to the invention. In particular, the first three substrate holders according to the invention are depicted more accurately than the last three substrate holders.

[0086] 1 shows the fastening surface of a substrate holder 1 according to the invention in a first exemplary embodiment according to the invention. The substrate holder 1 has a base body 2, in particular a plate. The base body 2 can be attached to an apparatus using fasteners 3. In the base body 2, the fastening area has two cutouts 4, in particular elongated holes, through which the backside of the substrate (not shown) can be observed.

[0087] In the center of the substrate holder 1 there is a deformation element 5, in particular a pin or nozzle. The substrate holder has two fastening elements 6, 6' according to the invention, which are particularly different in design. The outer fastening element 6 is particularly circular over the entire circumference. The fastening elements 6, 6'' are particularly very narrow recesses 11 which can be evacuated preferably through fluid openings 12 and thus function as vacuum fastening elements.

[0088] The inner fixing element 6' is configured as a network of recesses 11 over the remaining surface of the base body 2. The fixing element 6' is in particular also configured as a vacuum fixing element. The outer fixing element 6 is therefore the only fixing element belonging to zone 7. The inner fixing element 6' is the only fixing element belonging to zone 7'. The substrate holder 1 can further comprise various sensors 8, in particular pressure measurement sensors.

[0089] The zones 7, 7' are arranged in an annular, in particular circular, shape in both of the illustrated embodiments.

[0090] The number of pins 9 shown in the following figures is significantly reduced compared to the actual board holder. A board holder according to the invention can have hundreds or even thousands of such pins 9 per fixing element 6''.

[0091] 2 shows the fastening surface of a substrate holder 1' according to the invention in a second embodiment according to the invention. The base body 2 can be attached to the device by means of fasteners 3. The substrate holder 1' has a plurality of fastening elements 6'', in particular spaced apart radially and azimuthally.

[0092] The fastening element 6" is in particular a recessed, preferably milled, depression 11 in which the pins 9 are located at several locations. The pin surfaces of the pins 9 in particular coincide with the web surface of the web 10. The fastening element 6" is in particular configured as a vacuum fastening element. The depressions 11 can be evacuated independently of one another through fluid outlets 12, in particular individually, by separation by the web 10. If the fastening element 6" also functions as a deformation element, a fluid can also flow in through the fluid openings 12, which in turn leads to a particularly local deformation of the fastened substrate.

[0093] A number of fixing elements 6" together form a zone 7, while a further central fixing element 6" formed differently forms a second central zone 7'. A deformation element 5 preferably present in the center of the substrate holder 1' allows the fixed substrate to be deformed in particular centrally. The pins 9 in particular serve to reduce the contact area of ​​the fixed substrate and preferably prevent contamination. A number of sensors 8, in particular pressure sensors, may be distributed on the fixing surface of the substrate holder 1'.

[0094] FIG. 3 shows a further, more advantageous embodiment of a substrate holder 1″ according to the invention. The fixing elements 6, 6″ are located on the periphery of the substrate holder 1″ and are azimuthally separated from one another. The fixing elements 6 are, in particular, simple recesses 11, i.e., grooves, which are also very narrow, while the fixing elements 6″ are again configured as recesses 11 with pins 9 and fluid drains 12. Areas with recesses 11 with pins 9 can be located between the fixing elements 6, 6″. These areas may, but do not have to, be configured as fixing elements. Likewise, the central area may be configured exclusively as recesses 11 with pins 9 and / or may again function as fixing elements. It is also conceivable, as shown in the figure, for the central area to have a flat surface. In this case, the illustration has been chosen to focus on the peripheral fixing elements 6, 6″ and to emphasize them more. The substrate holder 1″ can again have sensors 8 and / or deformation elements 5. In particular, the individual fixing elements 6, 6″ can again function as fixing elements and / or deformation elements.

[0095] All of the illustrated embodiments of the invention are intended to disclose the concept of a plurality of fastening elements 6, 6', 6" which can be grouped into zones 7, 7'. However, the concept of zoning goes far beyond grouping individual fastening elements adjacent to one another. In other words, according to the invention, fastening elements which are not adjacent to one another can also be grouped into zones. In order to illustrate this aspect of the invention, the following figures do not show the substrate holder in full detail. Only the fastening elements referenced 6, 6', 6" and the zones referenced 7, 7', 7", 7'" are shown.

[0096] The zones shown azimuthally separated from one another have circular segment angles between 5° and 90°, preferably between 10° and 70°, even more preferably between 20° and 50°, very preferably between 22° and 30°, and most preferably about 22.5°.

[0097] The zones have a radial length of 50 mm to 1 mm, preferably 50 mm to 10 mm, even more preferably 50 mm to 20 mm, very preferably 50 mm to 30 mm, most preferably 50 mm to 40 mm.

[0098] 4 shows a further particular embodiment of the substrate holder according to the invention, in which there are three different zones. The first zone 7 consists of a total of 12 fixing elements 6, which are arranged diagonally in groups of three fixing elements 6 each. The second zone 7' consists of a total of 12 fixing elements 6, which are arranged on the left, right, top and bottom sides of the substrate holder according to the invention in groups of three fixing elements 6 each. There is also a large central zone 7'' which consists in particular of only a single fixing element 6.

[0099] Figure 5 shows a further particular embodiment of a substrate holder according to the invention, in which there are four different zones 7, 7', 7'', and 7'''. The first, outermost zone consists of four fixing elements 6 arranged along a circle. The same applies analogously to zones 7' and 7'', which are each present at a smaller radius. The fourth zone 7''' is a larger, in particular fully closed, zone which has an even smaller radius and in particular consists of only one fixing element 6.

[0100] Figure 6 shows a further particular embodiment of a substrate holder according to the invention, in which three different zones 7, 7', 7'' are present. The first zone 7 consists of six fixing elements 6, which are present in two groups of three fixing elements each at the top and bottom positions. The second zone 7' consists of six fixing elements 6, which are present in two groups of three fixing elements each at the left and right positions. A further large-area zone 7'' consisting in particular of only one fixing element 6 fills most of the remaining surface and even partially surrounds the two zones 7, 7'.

[0101] The concept that any number of fastening elements 6 can be grouped together to form any zone becomes clear from these shown figures. Why this zoning is necessary will be explained in further figures.

[0102] FIG. 7 exemplarily shows the substrate holder 1''' according to the invention of FIG. 4, except that the substrate holder 1''' now clamps a substrate 13, which in turn covers the clamping elements 6. However, the positions of the zones 7, 7' are shown. The arrows 14 indicate the mechanical anisotropy that should be compensated for before and / or during the bonding process by the zones 7, 7', 7'' according to the invention. The illustrated substrate 13 may have a direction-dependent elastic modulus, as is the case for example with cubic materials in the crystallographic (100) plane. Forces such as gravity acting uniformly on itself, which lead to sagging of the substrate 13, would thereby lead to anisotropic stretching within the substrate. It is also conceivable that clamping of the substrate solely by zone 7' would result in distortions, also referred to as mechanical anisotropy, which could possibly be compensated for by additional clamping of zone 7'' (which is covered by the substrate 13). The correct clamping of the individual zones for an optimal and desired compensation of the mechanical anisotropy 14 is ideally determined by testing. It is also noted that the individual clamping elements 6 of a zone may be configured to be arranged in particular radially. This arrangement allows in particular for radial adaptation while the bonding wave is moving from the center to the edge. [Explanation of symbols]

[0103] 1,1',1'',1''',1'''',1'''''' PCB holder 2 Base body 3 Fasteners 4 Hollow section 5. Transformation Elements 6,6',6'' fixed element 7,7' Zone 8 sensors 9-pin 10. Web 11 Recess 12 Fluid outlets, especially perforations 13 PCB 14 Mechanical Anisotropy

Claims

1. A substrate holder (1,1',1'',1''',1'''',1'''') for accommodating a substrate (13), said substrate holder (1,1',1'',1'',1''',1'''',1'''') comprising fixing elements (6,6',6'') for fixing said substrate (13), said fixing elements (6,6',6'') being groupable into zones (7,7'), said zones (7,7') being preferably arranged in an annular, more preferably in a circular annular, configuration.

2. 2. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''' according to claim 1, wherein the zones (7, 7') are arranged symmetrically with respect to the center of the substrate holder (1, 1', 1'', 1''', 1'''', 1''''').

3. 3. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''' according to claim 1 or 2, wherein the zones (7, 7') are arranged in a plurality of rings, preferably in a circular ring, around the center of the substrate holder (1, 1', 1'', 1''', 1'''', 1''''').

4. 4. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''' according to claim 1, wherein the zones (7, 7') are uniformly spaced apart in the radial and / or azimuth directions.

5. 5. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''' according to any one of claims 1 to 4, wherein the zones (7, 7') are configured to vary in width, in particular to increase in width, from the center of the substrate holder (1, 1', 1'', 1''', 1'''', 1''''') towards the edge of the substrate holder (1, 1', 1'', 1''', 1'''', 1'''''').

6. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of claims 1 to 5, wherein the zones (7, 7') are individually switchable.

7. 7. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of claims 1 to 6, wherein a plurality of zones (7, 7') can be grouped and switched together.

8. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of claims 1 to 7, wherein the number of the fixing elements (6, 6', 6'') in the zone (7, 7') is flexibly changeable.

9. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of claims 1 to 8, wherein the fixing elements (6, 6') can be flexibly allocated to different zones (7, 7').

10. The substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of the preceding claims, wherein the fixing elements (6, 6') are controllable across zones.

11. 11. A method for fastening and joining one or more substrates (13), in particular by means of a substrate holder (1, 1', 1'', 1''', 1'''', 1''''') according to any one of claims 1 to 10, wherein the fastening elements (6, 6', 6'') are grouped into zones (7, 7'), the zones (7, 7') being preferably configured in an annular, more preferably in a circular ring shape.

12. The method according to claim 11, characterized in that the zones (7, 7') are switched individually.

13. 13. A method according to claim 11 or 12, wherein a plurality of zones (7, 7') are grouped and switched together.

14. Method according to any one of claims 11 to 13, characterized in that the number of said fixing elements (6, 6', 6'') in said zone (7, 7') is flexibly changed.

15. Method according to any one of claims 11 to 14, characterized in that the fixing elements (6, 6') are flexibly allocated to different zones (7, 7').

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