Method and apparatus for bonding substrates

Abstract

The invention relates to a substrate holder (1 ', 1' ', 1' '') for bending a substrate (7), comprising: a fixing plate (3) for fixing the substrate (7); bending means (6, 6 ', 6' ') for bending the fastening plate (3), the fastening plate (3) being designed such that the curvature of the base (7) can be adjusted in a targeted manner.

Description

Technical Field

[0001] This invention describes substrate holders, apparatuses, and methods for bonding two substrates, according to the co-independent claims. Background Technology

[0002] Existing technologies disclose a large number of different substrate retainers. Especially in fusion bonding, substrate retainers are becoming increasingly complex and precise to meet the ever-increasing demands of the bonding process. Document WO2012083978A1 mentions a substrate retainer that can compensate for local and / or global deformation through active control using thermal, piezoelectric, or fluid elements. Document WO2013023708A1 discloses a substrate retainer that minimizes contamination of the substrate back side and a method for separating the substrate by selectively controlling the fixing elements. Document WO2017162272A1 discloses a substrate retainer with multiple fixing regions, which are particularly symmetrically distributed on the substrate retainer and can be switched individually. Document WO2018028801A1 discloses a method for fixing a substrate non-radially symmetrically but uniaxially and for releasing the substrate with uniaxial curvature. Document WO2014191033A1 discloses a substrate retainer with a curved or flexible surface to provide a non-uniform curvature to the substrate fixed thereon before and / or during substrate bonding. Document WO2014191033A1 specifically mentions on page 9 that the adjustable curvature is not uniform, i.e., non-uniform curvature. With each new generation of substrate retainers, better and faster bonding results have been achieved, but they can still be optimized through further technological improvements. It has also been recognized that the two substrate retainers are crucial in the bonding process. In particular, the control of the advancing bonding wave in fusion bonding is extremely important for correct bonding results. In particular, the control is also affected by the curvature of the substrate involved in the bonding process.

[0003] One problem with the prior art is that not only does the surface to which the substrate is fixed bend in a defined manner, but other components of the substrate retainer are also mechanically affected during the bending process, particularly bending. Technically, it is possible for the substrate retainer to be solid, i.e., a structure composed of very thick and bulky components with high bending resistance. However, some substrate retainers must be built small and compact, i.e., relatively delicate, and therefore necessarily have relatively low bending resistance. This low bending resistance then causes slight, undesirable, elastic deformation of several components of the substrate retainer, parts of which should not actually bend. These elastic deformations and bending react on the surface to which the substrate is fixed (the surface of the fixing plate), and thus affect the curvature of the substrate. It must be mentioned here that the resulting elastic deformation, of course, only occurs in the nanometer or micrometer range, but this order of magnitude of elastic deformation is sufficient to produce a negative reaction on the fixed substrate and its curvature.

[0004] A uniform, curved fixing surface can be created on the substrate holder through milling, grinding, polishing, etching, and lapping processes, thereby giving the substrate fixed thereon a uniform curvature. However, this fixing surface is static and its curvature cannot be changed. Alternatively, as described in document WO2014191033A1, it is possible to construct a substrate holder that allows the fixing surface to be curved. However, in these substrate holders, it has been found that it is difficult to selectively adjust the curvature of the fixing surface and thus the curvature of the substrate according to location, especially to keep it constant. In particular, adjusting the uniform curvature of the substrate is extremely difficult, practically impossible, or at least unreproducible. Summary of the Invention

[0005] The problem to be solved by the present invention is to eliminate the disadvantages of the prior art, and in particular to describe an improved substrate retainer, an improved device and an improved bonding method.

[0006] This objective is achieved through the features listed in the independent claims. Advantageous improvements of the invention are described in the dependent claims. All combinations of at least two features described in the specification, claims, and / or drawings also fall within the scope of the invention. In the case of stated value ranges, values ​​within the mentioned limits should also be applied as disclosed limit values ​​and can be claimed in any combination.

[0007] Of particular technical importance is the construction of the base retainer in such a way that it can bend the base in a targeted, adjustable, and especially uniform manner.

[0008] This invention relates to a substrate retainer for a bent substrate, which has: - A fixing plate used to secure the base; - Bending devices for bending fixed plates; The fixing plate is constructed in such a way that the curvature of the base or fixing plate can be adjusted in a targeted manner.

[0009] The fixing plate has a front side on which a base is fixed and a back side opposite to the front side. The fixing plate has a width, length, and thickness. In another embodiment, the fixing plate is designed radially symmetrically and is then defined by its radius and thickness. The width and length extend in a direction toward the surface of the fixing plate on the front side where the base is fixed. The thickness extends perpendicular to the surface of the fixing plate.

[0010] The thickness of the fixing plate is preferably varied, meaning that the thickness is different at each location, and the fixing plate is thicker at at least one location than at another. A particular construction scheme / preferred form will be described next.

[0011] Preferably, the uniform curvature of the fixing plate or base is adjustable.

[0012] Preferably, the fixed plate is hinged to the ground support.

[0013] Targeted adjustment means that the value of curvature can be determined. Uniformity means that, given a fixed value of curvature, the curvature is the same, i.e. constant, at every location on the fixed plate or substrate, within a negligible tolerance for error.

[0014] The back side of the fixing plate is preferably shaped such that a uniform curvature of the fixing plate is produced, or the uniform curvature of the fixing plate or the front side of the fixing plate and therefore the substrate, which is the same at every location, can be adjusted.

[0015] In a preferred embodiment, but also as a separate aspect of the invention, the base retainer is constructed such that the reaction force and / or torque generated when the fixed plate bends can be compensated by at least one compensating device.

[0016] As a separate aspect of the invention, the present invention relates to a base retainer for a curved base, which has: - A fixing plate used to secure the base; - Bending devices for bending fixed plates; The reaction force generated when the fixed plate bends can be compensated by at least one compensation device.

[0017] The present invention also relates to an apparatus, particularly a bonding apparatus, having at least one substrate retainer according to the invention.

[0018] The present invention also relates to a method for bonding two substrates, comprising the following steps, wherein: - Secure the first base to the first base holder, particularly according to the invention; - Secure the second base to the second base holder, particularly according to the invention; - Align the bases (7) relative to each other; - Bend at least one of the bases (7); - Contact substrate; The curvature of at least one of the base or fixing plates is specifically adjusted, preferably uniform.

[0019] Preferably, and as an independent aspect of the invention, when the fixed plate bends, the torque and / or reaction force generated in the remaining components are compensated, but preferably not transmitted at all or only to a small extent to the fixed plate.

[0020] Therefore, another independent aspect of the invention relates to a method for bonding two substrates, comprising the steps of: - Secure the first base to the first base holder, particularly according to the invention; - Secure the second base to the second base holder, particularly according to the invention; - Align the bases relative to each other; - Bend at least one of the substrates; - Contact substrate; When the fixed plate bends, the torque and / or reaction force generated in the other components are compensated, but preferably not transmitted at all or only to a small extent to the fixed plate. This is preferably achieved by using a bearing, through which the reaction force and / or torque are transmitted as little as possible or only very little.

[0021] Preferably, the fixing plate is thicker at the center than at the edges. This advantageously allows for a particularly uniform curvature between the fixing plate and the substrate. Preferably, the fixing plate is constructed to taper towards the edges. Preferably, the fixing plate is constructed symmetrically with respect to the center.

[0022] A key aspect of the invention lies in the fact that the substrate can be given curvature, which can be specifically adjusted. In particular, a curvature with a constant, i.e., uniform radius of curvature can be produced. Adjusting the constant curvature is the most preferred method according to the invention for generating bonding. Through extensions and embodiments according to the invention, the reaction force, which is always generated according to Newton's third law, is not absorbed by the components of the substrate retainer connected to the plate of the fixed substrate via mechanical coupling, but is absorbed by a second plate (compensation plate), which is located inside the substrate retainer and freely (hingedly) supported together with the first plate, i.e., ideally, it transmits no or only negligible small torque.

[0023] Curvature refers to the deviation of an object's shape from its initial unloaded state, and its characteristic is that the position of the object's centerline or center plane changes under load.

[0024] The simplest description of curvature is the reciprocal of the radius of curvature at a point on a curve. The radius of curvature at a point is the radius of the osculating circle of the curve passing through that point. The larger the radius of curvature, the smaller the curvature.

[0025] In the semiconductor industry, there is also the term "bow." This refers to the deviation between the center point of the mid-surface of a free, unclamped substrate, especially a wafer substrate, and the mid-surface of a reference plane. The reference plane is simply a horizontal plane on which the substrate is clamped and placed. A precise definition can be found in the now-obsolete ASTM F534 standard.

[0026] In the following text, the terms "curved line" and "curved surface" will be used synonymously, especially since the base retainer according to the invention is preferably drawn in cross-section in the drawings, and therefore only curved lines, not curved surfaces, are visible. Those skilled in the art will understand that the two-dimensional surface of a three-dimensional body generally has curved surfaces, and only curved lines are visible or presented in the cross-section through this curved surface.

[0027] In a particularly preferred embodiment of the substrate retainer and method according to the invention, the substrate is bent with a constant curvature, i.e., the curvature is the same at every location on the substrate. The curvature is thus also referred to as uniform. The constant curvature of the substrate produces a particularly optimal bond between the two substrates. Such bending can be achieved especially if it is ensured that no reaction forces and / or moments from other components act on the fixing plate. This is preferably achieved by using bearings that do not allow the transmission of reaction forces and / or moments, or only allow a very small amount of transmission.

[0028] Generally, curvature can also vary on the substrate. However, the curvature is preferably radially symmetrical, meaning it varies only with the radial position measured from the center of the substrate and not with the angle. Substrates with anisotropic curvature (i.e., whose curvature typically varies with both radial position and angle) have the characteristic of forming a saddle-shaped surface. However, since the stiffness of the fixing plate according to the invention, and especially the entire substrate retainer according to the invention, is much greater than the stiffness of the substrate, and the substrate is fixed to the fixing plate by fixing elements, it can be considered that the substrate is in contact with the fixing plate at every point. In this case, the constraint condition that does not allow bending in the form of a saddle-shaped surface will result in inherent stresses in the substrate.

[0029] The radius of curvature of the plate or substrate is greater than 0.01m, preferably greater than 0.1m, even more preferably greater than 1m, most preferably greater than 10m, and of all the most preferably greater than 100m.

[0030] If the radius of curvature is not constant along the curvature line or curvature surface, the absolute value of the difference between the maximum radius of curvature and the minimum radius of curvature is less than 1m, preferably less than 0.1m, even more preferably less than 0.01m, most preferably less than 0.001m, and of all the most preferably less than 0.0001m.

[0031] The curvature is less than 1000 μm, preferably less than 500 μm, even more preferably less than 100 μm, most preferably less than 10 μm, and of all the most preferred less than 1 μm.

[0032] According to the embodiments and methods of the present invention, the substrate can preferably be bent such that the surface or bending line in the cross-sectional profile can be described by one of the following mathematical functions: ● Elliptical segment, preferred ○ Circular section ● Parabola ● Hyperbola ● Sine, especially in the range [0, Pi]. ● Negative hyperbolic cosine.

[0033] Then, the curved surface can be described, in particular, by one of the following functions: ● Elliptic section, especially ○ Round shell section ● Parabolic surface ● Hyperboloid Therefore, generally speaking, a curved surface is a surface created by rotating a curved line.

[0034] Of all the possible curved line shapes or curved surface shapes mentioned above, the most preferred are those with uniform curvature, namely circular segments or circular shell segments.

[0035] This preferred adjustability of uniform curvature is achieved through the precise definition of the fixing plate and the precisely manufactured cavity plate surface. By creating the defined and precisely manufactured cavity plate surface of the fixing plate, the final shape of the fixing plate and thus the fixing surface of the substrate is precisely defined. In particular, the shape of the cavity plate surface of the fixing plate is determined using computational methods, preferably the finite element method. Specifically, the shape of the cavity plate surface of the fixing plate can be described by one of the aforementioned mathematical functions.

[0036] However, the actual shape of the cavity plate surface to be manufactured for the fixing plate depends on many factors: - The bending resistance of the fixed plate; - Bending resistance of the entire base retainer; - The bending devices used, especially - The fluid pressure used when using the fluid; - etc.

[0037] The invention is particularly evident in the precise manufacture of a single, rigid, hollow plate surface for the fixing plate, and then using this hollow plate surface, any curvature at the fixing surface of the fixing plate and thus at the base can be set by a controllable adjustment device, especially in such a way that the curvature at the base is uniform, i.e., the same at every location.

[0038] According to the present invention, this method of selectively adjusting the curvature of the substrate is further supported and improved by using at least one compensation device to reduce or completely prevent mechanical reactions when the fixing plate is bent, via the precisely manufactured cavity plate surface that produces the fixing plate.

[0039] Preferably, at least one compensation device includes, in particular, a flexible compensation plate.

[0040] Preferably, the compensation plate can be bent with the opposite curvature to that of the fixed plate.

[0041] Preferably, a sealed intermediate space is created between the fixed plate and the compensation plate.

[0042] Preferably, the curvature of the fixed plate and the compensation plate can be generated by a fluid that can be squeezed into the intermediate space.

[0043] Preferably, the intermediate space can be generated by fluid devices, mechanical adjustment devices, and / or electrostatic forces.

[0044] Preferably, the fixing plate and the compensation plate are connected to each other via a preferred hinged support.

[0045] Preferably, the fixing plate and the compensation plate are connected to the rest of the base retainer via a preferred hinged support.

[0046] Preferably, the configuration allows only a small torque to be transmitted via the periphery of the fixed plate and / or the compensating plate, and more preferably, no torque is transmitted. The transmitted torque is less than 1 Nm, preferably less than 10 Nm. -3 Nm, and more preferably less than 10 -5 Nm, optimal value is less than 10 -7 Nm, the best option among all is 0Nm.

[0047] Preferably, the compensation plate has a groove in its outer region, preferably a complete and closed groove. The distance between the groove and the outer periphery of the compensation plate is less than 50 mm, preferably less than 40 mm, even more preferably less than 30 mm, most preferably less than 20 mm, and of all, most preferably less than 10 mm.

[0048] Preferably, the compensating plate has a sealing device, preferably a sealing ring, in its outer region, wherein the sealing device is preferably arranged on a support, particularly a fully closed support. The sealing ring allows for a pressure exceeding 1 bar, preferably exceeding 1.2 bar, even more preferably exceeding 1.5 bar, most preferably exceeding 2 bar, and of all, most preferably exceeding 2.5 bar.

[0049] Preferably, at least one compensating device includes a hinged support for the fixed plate. The hinged support itself, which cannot transfer reaction forces and / or torques from other components of the base retainer according to the invention to the fixed plate, is also considered a compensating device in the sense of this disclosure.

[0050] Another preferred embodiment of the invention is based, in particular, on the concept of constructing a substrate retainer having two plates that can be bent in two corresponding opposite directions. Here, bending is achieved by means of an adjusting device (hereinafter also referred to as a bending device), particularly by means of fluid squeezed into the intermediate space between the two plates. By using the two plates, the reaction force generated by the deformation of the first plate does not act on the bottom surface of the substrate retainer holding the first plate, but rather on the second plate installed according to the invention. This eliminates the harmful and influential reaction of the reaction force on the substrate retainer and therefore the substrate. Specifically, the reaction force is absorbed (compensated) by the second plate, which can be freely deformed in the direction of the substrate retainer. Furthermore, the invention describes an apparatus, particularly a bonding apparatus, that uses the substrate retainer according to the invention at at least one side of the apparatus.

[0051] Base retainer The base retainer according to the invention is described in detail below. Of particular importance is understanding all the structural technical measures by which an adjustable, especially uniform curvature can be produced. Furthermore, structural technical measures are disclosed by which the reaction forces and moments acting on the upper plate and their avoidance can be understood.

[0052] All base retainers according to the invention have a fixed surface. The fixed surface is, in particular, part of a fixed plate. The fixed plate has a cavity surface opposite the fixed surface. Preferably, the cavity surface is shaped according to a mathematical function. The shape of the cavity surface is achieved by using adjusting elements to induce a clearly defined, particularly uniform, curvature.

[0053] The normal component of the force acting on a lever produces a torque at the point of application of the lever. For the sake of simplicity, only forces will be discussed in the following description, although the forces produced also cause torques. The sum of the torques and the sum of the forces must be zero. Therefore, all consequences arising therefrom are also considered disclosed.

[0054] The base retainer according to the invention is preferably always constructed such that a force causes the upper first plate to bend, and the resulting reaction force is not absorbed by the members supporting or retaining the plate, but by a compensating member specifically provided for this purpose, in particular the lower second plate. The lower second plate should not, or should only be very weakly, mechanically connected to the rest of the base retainer, because otherwise it would again be mechanically connected to the upper first plate and could transmit torque. A characteristic feature is that torque cannot be transmitted via the periphery, particularly the periphery of the two plates, or at least only a negligible small torque can be transmitted. Therefore, the plates and some other necessary mechanical components must form ideal loose bearings, and in particular ideal hinges, at their peripheries.

[0055] In a particularly preferred embodiment, the base retainer according to the invention thus consists of at least two plates that are flexible and, in particular, hingedly supported.

[0056] In a particular, preferred first embodiment of the invention, the plate itself is an adjusting element that causes the plate to bend by placing it at a potential, generating a surface charge, and providing an electrostatic force for bending the plate. The plates are electrically insulated from each other. Such insulation may be achieved by the surfaces in the periphery of the substrate being made of or coated with a dielectric material.

[0057] Other areas of the plates, especially the areas where the plates face each other, are conductive (Elektrika), meaning they can conduct electricity. In particular, the entire plate is conductive, except for their insulated edge regions. The two plates can be placed at a potential relative to ground, especially a positive potential. It is also conceivable to place the two plates at a negative potential relative to ground. Because the two plates are charged at their same poles, they repel each other. If the plates were not electrically insulated at their perimeters, the charge would move to the outer surfaces of the two plates. There is no charge at the inner surfaces of the two plates facing the cavity, and the cavity will be field-free.

[0058] Therefore, according to the invention, the plates cannot bend outwards. Thus, the electrical insulation of the two plates at potential is an important aspect of this very particular embodiment according to the invention. In a particular extension of the embodiment according to the invention, the regions of the two plates that are electrically insulated from each other can be conductive, and each of these conductive regions can be placed individually and independently of the other electrical regions at a clearly defined potential. This allows for localized and precise adjustment of the repulsive force of the plates. The finer the division of the conductive regions, the more precise the local resolution of the adjustable curvature.

[0059] In a particular, preferred second embodiment of the invention, the two plates are bent by a mechanical adjusting element located between the plates. The mechanical adjusting element can be electrically and / or pneumatically and / or hydraulically operated. Particularly preferably, a piezoelectric column is used as the adjusting device. In particular, multiple such mechanical adjusting elements can also be used again, located at multiple, particularly symmetrical, positions between the plates. In this case, each of the adjusting devices can preferably be adjusted independently of all the other adjusting devices.

[0060] In a particular, preferred third embodiment of the invention, the plates are bent by a fluid introduced, in particular pumped, into the intermediate space. The fluid is a liquid, a liquid mixture, a gas, or a gas mixture. Most preferably, the fluid is air. This results in a particularly symmetrical bending of the two plates.

[0061] The concept behind a particular embodiment of the invention is that the lower plate can extend freely without transmitting forces and / or torques to the remaining components of the base retainer, thus preventing deformation of the base retainer. In particular, the curvature of the first plate (fixed plate) and therefore the curvature of the base fixed thereto should not be altered by mechanical reaction torques or mechanical reaction forces.

[0062] plate The base retainer according to the invention particularly has at least one plate specially shaped on its back side. In a particular embodiment of the invention, the base retainer has two plates.

[0063] There are two basic types of plates: fixed plates and compensating plates. A fixed plate is a plate on which the base to be bent is fixed. A compensating plate is a plate that absorbs the force and / or torque of the adjusting device according to the invention, and thus largely prevents mechanical feedback to other components of the base holder. In particular, the support of the plate also primarily determines that no force and / or torque is transmitted from other components to the fixed plate.

[0064] The space between two plates is called a cavity. All plates have a cavity plate surface and a second plate surface opposite to the cavity plate surface, which is used depending on the function of the plate.

[0065] The cavity plate surface is always the surface facing the cavity between the two plates. In a particularly preferred embodiment according to the invention, the cavity plate surface is specifically shaped. In particular, the cavity plate surface of the plate fixing the substrate has a well-defined shape that positively influences the bending characteristics of the plate, and therefore positively influences the bending characteristics of the substrate.

[0066] If a distinction needs to be made between the cavity plate surfaces of the fixed plate and the compensating plate, then these cavity plate surfaces are accordingly referred to as the cavity fixed plate surface and the cavity compensating plate surface. The cavity plate surfaces can be arbitrarily shaped, but are preferably described according to functions already used to describe curved lines or curved surfaces. Therefore, all functions disclosed for curved lines and / or curved surfaces are also considered to be disclosed for the description of the cavity plate surfaces.

[0067] The surface of the plate that holds the substrate is called the fixed plate surface. Therefore, the fixed plate surface can only be located on the fixed plate.

[0068] The surface of the fixing plate has fasteners for securing the base. The fasteners may, in particular, be: 1. Mechanical fasteners, especially 1.1. Fixture 2. Vacuum fasteners, especially those with... 2.1. Individually operable vacuum track 2.2. Interconnected vacuum orbits 3. Electrical fasteners, especially 3.1. Static electricity fixing components 4. Magnetic fasteners 5. Adhesive fasteners, especially 6. Gel-Pak fasteners, and / or 7. Fixtures with adhesive, especially maneuverable, surfaces.

[0069] The fasteners can be pneumatically and / or hydraulically and / or electronically operated.

[0070] Vacuum fasteners are the preferred type of fastener. Vacuum fasteners preferably consist of multiple vacuum tracks exiting from the surface of the substrate holder. These vacuum tracks are preferably individually operable. In a more technically feasible application, some vacuum tracks are combined into vacuum zones, which are individually operable and can therefore be evacuated or filled. However, each vacuum zone is independent of the others. This allows for the possibility of constructing individually controllable vacuum zones. These vacuum zones are preferably constructed in a ring shape. This allows for targeted, radially symmetrical, and especially inside-out, fastening and / or separation of the substrate and substrate holder.

[0071] In a further improvement, the annularly divided vacuum region is further divided along the circumference of the ring, so that each vacuum region is divided into multiple vacuum regions along the circumference of the ring. This implementation has been disclosed in detail in document WO2017162272A1.

[0072] In a particularly preferred embodiment of the invention, so-called pins are present on the surface of the mounting plate. This structure is mentioned in document WO2015113641A1. Due to these pins, the substrate does not lie entirely on the mounting surface, but rather mostly contacts the mounting surface only at the pins. This reduces contamination on the one hand, and allows a vacuum to be created in the intermediate space between the pins along the entire mounting surface of the mounting plate. In particular, the pins are grouped in the vacuum region already mentioned. These embodiments are also disclosed in detail in document WO2017162272A1. In particular, the grouping of the pins and vacuum feedthroughs into the vacuum region (which is distributed on the mounting plate and can be manipulated individually) is explicitly disclosed here, and, combined with the actual concept according to the invention, constitutes a decisive improvement of the substrate holder according to the invention.

[0073] Although the use of the vacuum region mentioned in document WO2017162272A1 (which can be evacuated or filled by at least one vacuum hole) is considered a particular, beneficial and important extension of the concept according to the invention, the base retainer according to the invention is described in the following content together with the fixing method, wherein a very small number of vacuum holes are present on the surface of the fixing plate, especially in the center.

[0074] In an embodiment of the invention where the substrate is fixed using a vacuum clamp, the vacuum between the substrate and the surface of the fixing plate is preferably generated via a vacuum hole drilled along a circle whose center is the center of the fixing plate. This allows for precise positioning of one of the pins at the center of the fixing plate when using a pin chuck, which has a significant positive impact on the bonding results. A precise description and presentation are given in the accompanying drawings. Therefore, another feature of the invention is the disclosure of a pin chuck with one pin located precisely below the point where the initial contact of the two substrates occurs. This pin, located below the contact point of the two substrates, enables mechanical stabilization of the substrate at that point. Since the bonding wave begins its journey from this point, the coincidence of this pin with the contact point along a line normal to the surface of the fixing plate is crucial for the stable initiation of the bonding wave. The effect of the pin being precisely below the contact point can be illustrated as follows: the pin below the contact point prevents the substrate from being pressed over at that point, thus resulting in a stable initial mechanical condition.

[0075] The second plate is a compensating plate. The compensating plate preferably has a complete and closed groove in its outer region. The groove is for the bending of the lower plate to not continue all the way to its edge, but rather mainly extends to the groove. The groove thus intercepts the bend before it reaches the periphery. This further reduces the small reaction forces that may still be present on the base retainer. If the compensating plate is well supported at the periphery to the point of not transmitting torque, the corresponding groove can be omitted. However, such a groove implementation is always practically advantageous. The compensating plate preferably also supports sealing devices, particularly sealing rings. The sealing devices are preferably located on smaller, complete, and closed supports.

[0076] equipment All substrate retainers according to the invention can be used in devices according to the invention to secure a lower substrate and / or an upper substrate. The substrate retainers according to the invention are particularly preferred for securing a lower substrate and an upper substrate in bonding devices. This significantly improves and optimizes the control of bonding, especially fusion bonding. By using the substrate retainer according to the invention as an upper substrate retainer, the bent pins that have long been used in the semiconductor industry, which initiate the center bending of the substrate, are particularly advantageous.

[0077] A preferred embodiment of the device according to the invention is that a base retainer according to the invention is used to fix the upper base and a base retainer according to the invention is used to fix the lower base.

[0078] A particular device according to the invention comprises a base retainer according to the invention located on the lower side and any other base retainer not according to the invention. Here, the upper base retainer preferably has a bending device known in the art, in particular a bending pin or nozzle, which accordingly causes fluid from the upper base to bend and exit therefrom.

[0079] In a particular extension of the device according to the invention, an alignment device is also present in the bonder.

[0080] If the substrate is transparent to electromagnetic radiation of a certain frequency, it is preferable to have a monitoring device to analyze the changes in the bonding wave. This allows not only observation, influence, and, if necessary, termination of the bonding process, but also analysis of the characteristics of the bonding wave based on different parameters. This analysis contributes to further improvements to the substrate retainer according to the present invention.

[0081] In a particular extension of the device according to the invention, the following modules can be connected to the device according to the invention, in particular, in a vacuum-sealed manner: ● Cleaning module ● Grinding module ● Etched modules, especially ○ Used for chemical etching ○ Used for physical etching ● Plasma module ● Coating module Such modules are preferably part of a so-called cluster device, wherein vacuum-sealed doors exist between the modules. Preferably, gates also exist between some of the aforementioned modules. The modules can be arranged arbitrarily relative to each other. Preferably, there is a central module containing a robot that can transfer substrates between the modules. This centrally designed cluster is called a star cluster. It is also conceivable to arrange the modules in series.

[0082] method In particular, the method according to the invention includes the following steps. These steps do not necessarily have to be performed in the order mentioned.

[0083] In the first process step according to the invention, a first substrate is loaded and secured to a first substrate holder. The first substrate holder is preferably a substrate holder according to the invention.

[0084] In the second process step according to the invention, the second substrate is loaded and secured to the first substrate holder. The first substrate holder is preferably a substrate holder according to the invention.

[0085] In the third process step according to the invention, the two substrates are aligned relative to each other. Alignment is preferably performed by means of alignment marks located on the substrate surfaces of the substrates. Corresponding alignment devices are disclosed in documents US6214692B1, WO2015082020A1, WO2014202106A1, and WO2018041326A1, which can also be part of the device according to the invention, particularly the bonding chamber.

[0086] In the fourth process step according to the invention, the substrates are roughly brought close together.

[0087] In the fifth process step according to the invention, the targeted, particularly uniform curvature of at least one substrate is adjusted according to the invention using a substrate holder according to the invention. It is also conceivable to bend both substrates, particularly both using a substrate holder according to the invention. The particularly uniform curvature can be achieved through the specially shaped back side of the fixing plate. With the curvature being targeted for adjustment, contact occurs between the two substrates at a certain time, and thus a bonding wave occurs.

[0088] For completeness, the following supplementary explanation is provided. If one of the substrate holders is not a substrate holder according to the invention, then the substrate holder may have a common deformation element known in the art for deforming the substrate. Such a substrate holder not according to the invention then naturally has all the negative consequences, which are eliminated by the inventive concept of this document. However, it is conceivable that a single substrate holder according to the invention alone is sufficient to produce a good bond, thus allowing the use of a common substrate holder in the art on the other side. The deformation element is then preferably a simple bent lead. This bent lead should not be confused with the much smaller leads of a pin chuck.

[0089] In the sixth method step according to the invention, the substrate is continuously, selectively, and particularly controlledly separated from the substrate holder. It is particularly advantageous here that at least the upper substrate holder is not only a substrate holder according to the invention, but also allows for locally and selectively controlled fixation at its fixing surface. This is especially possible if the fasteners are grouped into areas, particularly vacuum areas, as detailed in document WO2017162272A1.

[0090] Therefore, an important aspect of the method according to the invention is that, by means of the substrate retainer according to the invention, the curvature of the substrate can be selectively adjusted, which is made possible only because there is no mechanical feedback on the substrate during the advance of the bonding wave to selectively control the separation of the substrate from its fixed surface. Attached Figure Description

[0091] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and with reference to the accompanying drawings. Wherein: Figure 1a The initial state of a substrate retainer in the prior art is shown; Figure 1b This illustrates the final state of a substrate retainer in the prior art; Figure 2a The initial state of the base retainer without a compensation plate according to the present invention is shown; Figure 2b The final state of the base retainer without a compensation plate according to the present invention is shown; Figure 3a The initial state of the extended base retainer with a compensation plate according to the present invention is shown; Figure 3b The final state of the extended base retainer with a compensation plate according to the present invention is shown; Figure 4A first embodiment of a base retainer with a compensation plate according to the present invention is shown; Figure 5 A second embodiment of the base retainer with a compensation plate according to the invention is shown; Figure 6a A preferred third embodiment of the base retainer with a compensation plate in its initial state, according to the present invention, is shown in side and top views. Figure 6b A preferred third embodiment of the invention, showing a base retainer with a compensation plate in its final state, is illustrated in a side view.

[0092] In the figures, the same components or components with the same function are represented by the same reference numerals. Detailed Implementation

[0093] The following two figures, along with their related figures, illustrate two states of a substrate retainer in the prior art. They are kept as general as possible to elucidate the basic concepts. This is a description and schematic sketch as simple as possible, and completeness is not required.

[0094] Figure 1a A schematic diagram of the initial state of a base retainer 1 in the prior art is shown, wherein the surface 3f of its fixing plate is flexible. The base retainer 1 has a fixing plate 3, which is particularly supported on a plate support 2, especially at the periphery. In the present case, the plate support 2 is in particular a fixed bearing, which is not designed to be hinged. Of course, it is also conceivable that the fixing plate 3 is directly mechanically connected to the rest of the base retainer 1. Importantly, there is a flexible surface described as the fixing plate surface 3f. The fixing plate 3 is therefore constructed and / or supported in such a way that it can be bent.

[0095] In particular, a base fixing member 4 is provided on the plate 3, by means of which the base 7 can be fixed to the plate 3. How to manipulate the base fixing member 4 is irrelevant to understanding the prior art and will not be explained in more detail here.

[0096] Figure 1b A schematic diagram of the final state of the base retainer 1 in the prior art is shown. In this particular case, the base retainer 1 is convexly curved when viewed from the outside because an overpressure is created in the cavity 5. The overpressure is generated by the flow of gas or gas mixture into the cavity 5 at an overpressure relative to the surrounding atmosphere via an adjusting device 6 (in particular cases, an opening, valve, or nozzle). Alternatively, the adjusting device 6 may be a mechanical adjusting device. The use of overpressure is described herein only by way of example.

[0097] This situation presents several fundamental problems. The first problem is that the curvature of the fixed plate surface 3f, and therefore the curvature of the base 7, is generally non-uniform, meaning the curvature typically varies with position. This is generally undesirable. The non-uniformity of curvature is difficult to discern in the figures. This problem is particularly relevant to the fact that bearing 2 is designed as a fixed bearing (i.e., the number of degrees of freedom is too small or even zero).

[0098] Another problem in the prior art is with bearing 2, which is typically designed to transmit reaction forces and / or torques to fixed plate 3. In particular, bearing 2 is not hinged in the prior art. Therefore, bearing 2 is typically capable of transmitting torque in the prior art.

[0099] Another problem is that any adjusting element 6 responsible for the deformation of the fixing plate 3 always generates a reaction force. In general and physically terms, according to Newton's third law, a reaction force is generated, and a corresponding counter-pressure is produced in the normal direction to the surface, which causes the base retainer 1 to bend in another direction. This undesirable bending of the base retainer 1 has a particularly strong reaction force on the plate support 2, and therefore also affects the bending characteristics of the fixing plate 3 and the bending of the base 7 fixed to the fixing plate 3.

[0100] This relates to the aforementioned problem, in the prior art, where the plate support 2 is implemented in such a way that reaction forces and / or torques can be transmitted. Even when adjusting the final state in terms of control technology, a reaction caused by the base retainer 1 can be observed, which is absolutely undesirable because measurements have shown that the bonding results to be performed are thus deteriorated. It is explicitly mentioned and emphasized that the mentioned mechanical feedback effect certainly does not depend on the type of adjusting device 6 (in this exemplary case, an opening through which gas or a gas mixture flows) nor on the presence of cavity 5.

[0101] Adjustment device 6 can also be a mechanical adjustment device, pin, piezoelectric post, bellows, or any other adjustment device that allows the fixed plate 3 to bend. In these cases, the corresponding cavity 5 may not be present. Fundamental physical laws always require mechanical feedback to the base retainer.

[0102] To clarify the basic concepts, the following description or drawings (which correspondingly illustrate two states of the two base retainers 1', 1'' according to the invention) are kept as general as possible. This is a description and schematic sketch as simple as possible, and completeness is not required. Embodiments according to the invention are then described in more detail in the following drawings.

[0103] The concept of the invention is further illustrated by means of a device that uses a fluid to generate overpressure in the cavity 5, which causes the fixing plate 3, to which the base 7 is fixed, to bend. It is emphasized again that the concept of the invention is not limited to the use of fluid and / or the cavity 5. Aspects of the invention can also be implemented by means of mechanical, pneumatic, electrical, or piezoelectric adjusting devices 6, as will be shown and explained later in particular embodiments.

[0104] Figure 2a A schematic diagram of the initial state of the base retainer 1' according to the invention is shown, by which at least one uniform curvature can be adjusted. Assuming the base retainer 1' has such high bending resistance that the problem of mechanical feedback (the elimination or reduction of which will be described in more detail in the following figures) does not yet arise. For example, the improvement in bending resistance can be achieved very simply by making some components of the base retainer 1', especially the entire base retainer 1', thicker. Importantly, the support member 2' is manufactured such that no reaction force and / or torque is transmitted, or only a very small one is transmitted, to the fixing plate 3. In particular, the shape of the cavity plate surface 3h is chosen such that subsequent bending of the fixing plate 3 produces a well-defined, particularly uniform curvature.

[0105] Figure 2b A schematic diagram of the final state of the base retainer 1' according to the invention is shown, which allows adjustment of at least one uniform curvature. Even though the base retainer 1' according to the invention has high bending resistance, it still requires slight bending when using the adjusting element 6, even if only to a small extent. However, due to the relatively high bending resistance, this bending is relatively small. However, without the support 2', the resulting force and / or torque will be transmitted to the fixing plate 3.

[0106] The particularly uniform curvature at the fixed surface 3f and thus at the base 7 can be adjusted by a special support member 2', because any possible reaction forces and / or torques are not transmitted or are transmitted only to a lesser extent to the fixed plate 7. In addition to the components already implemented in a solid construction manner, the support member 2' here also supports the construction of uniform curvature. In particular cases, an adjusting device 6 is used to adjust the curvature; this adjusting device is an opening, nozzle, or valve by which fluids, especially gas mixtures, preferably air, are compressed.

[0107] The embodiment of the invention, with its specially shaped cavity plate surface 3h, gains particular significance through the use of a fluid. By using a fluid that applies uniform and isotropic pressure to the cavity plate surface 3h, an assumed force distribution along the cavity plate surface 3h can be assumed, wherein the force is always normal to the cavity plate surface 3h.

[0108] Because of this assumption, it is particularly easy to calculate the suitable shape of the cavity plate surface 3f using numerical simulation, especially the finite element method, in order to obtain the desired, especially uniform curvature at the fixed surface 3f and therefore the fixed base 7. This particular shape of the cavity plate surface 3f further improves the construction of the uniform curvature of the fixed plate surface 3f and therefore the base 7.

[0109] Figure 3a A schematic diagram of the initial state of a further improved base retainer 1'' according to the invention is shown, which allows adjustment of at least one uniform curvature and further minimizes the detrimental effects of mechanical feedback on the plate support 2'. This improvement according to the invention is particularly advantageous if the base retainer 1'' is designed to be relatively thin and have very low bending resistance.

[0110] Mechanical reaction forces can no longer be ignored and should be at least reduced, and advantageously eliminated, by means of the improved embodiment according to the invention. The advantages of the specially shaped cavity plate surface 3h will not be elaborated here. The base retainer 1'' has a fixing plate 3 and a compensating plate 3', which are supported via plate supports 2'. The plates 3, 3' are constructed and / or supported in such a way that they can be bent.

[0111] For completeness, it is mentioned that plate 3 does not theoretically need to be a separate component, but can be part of the base retainer 1'. Importantly, only the surface 3f of the fixed plate is present. However, this would result in boundary conditions that make it almost impossible to produce a constant curvature for the surface 3f of the fixed plate. Therefore, according to the most preferred embodiment of the invention, the fixed plate 3 is configured as a separate component. Thus, the effect of the invention is particularly evident in the use of the compensating plate 3'.

[0112] In the following description of the accompanying drawings, each embodiment of the invention thus presents a preferred solution in terms of construction technology, consisting of two plates. In particular, a base fixing member 4 is provided on the fixing plate 3, by means of which the base 7 can be fixed to the fixing plate 3. How the base fixing member 4 is manipulated is irrelevant to understanding this device and will not be explained in more detail here. The following figure will illustrate how the base fixing member 4, implemented as a vacuum fixing member, is manipulated.

[0113] Figure 3b A schematic diagram of the final state of a further improved base retainer 1'' according to the invention is shown. Fluid is forced into the cavity 5 by adjusting the device 6 (in this particular case, an opening, valve, or nozzle), which causes the two plates 3, 3' to bend. (Compared to...) Figure 1aCompared to existing technologies, the other parts of the fastener 2 or the base retainer 1' do not bend, and therefore do not generate additional torque on the fixing plate 3 and the base 7 fixed thereon via the fastener 2. Therefore, bending of the fixing plate 3 is achieved only by the effect of the adjusting device 6.

[0114] Therefore, the compensating plate 3' can be considered a "sacrificial plate" whose sole purpose is to prevent or at least minimize the effect of forces on the remaining components of the base retainer 1'. In particular, plates 3, 3' must be sealed, especially around their perimeter. For clarity, details, particularly the depiction of the seals, are omitted from this schematic diagram. However, the seals are discussed in more detail in the accompanying drawings shown later in the preferred embodiment.

[0115] Different embodiments of the invention are discussed and illustrated separately and in detail in the additional accompanying drawings.

[0116] Figure 4 A preferred first embodiment according to the invention is shown, wherein two plates 3,3' are placed at potentials having the same sign, and in particular the same value. To prevent the two plates 3,3' from forming a conductive, self-closed entity, the plates 3,3' must be electrically insulated from each other at their contact points by means of an electrical insulator 14. Otherwise, according to the laws of physics, all charges on the surfaces 3h,3h' of the cavity plates forming the cavity 5 will migrate outwards.

[0117] The self-closed main body will form a Faraday cage, and the charge will be stored only on the outer side. The electrical insulator 14 ensures that the two plates 3,3' do not form a self-closed conductive main body from an electrostatic perspective, but rather form conductive main bodies separately. This allows charge to be generated at the substrate surface forming the cavity 5. The charge located on the cavity plate surface 3h,3h' or the two plates 3,3' themselves, together with the necessary circuitry 15, accordingly constitutes the adjustment device 6'.

[0118] Figure 5 A preferred second embodiment according to the invention is shown, wherein an adjusting device 6'' exists between the two plates 3,3'. The adjusting device 6'' can be, for example, an electrically and / or pneumatically and / or hydraulically operable mechanical adjusting element. Electrically operable piezoelectric columns are also conceivable. The adjusting device 6'' can also be two very strong electromagnets that electrically generate two magnetic fields that repel each other, causing the two plates 3,3' to move away from each other. Embodiments are also conceivable in which the two plates are placed at the same potential and repel each other due to their electrostatic charge.

[0119] Figure 6a A preferred third embodiment of the invention in its initial state is shown in a side view, detailed view, and top view. This embodiment of the invention is... Figure 3a and Figure 3b The embodiments are described in more detail below. The illustrations include (i) a special bearing 2' and (ii) a compensating plate 3', through which minimal or only very small reaction forces and / or torques can be transmitted.

[0120] The importance of this implementation lies particularly in the use of a fluid to bend the two plates 3,3', which has an isotropic (i.e. uniform) force effect on the two plates 3,3', but especially on the fixed plate 3, due to hydrostatic pressure. Figure 6a All the features mentioned in the figure can also be used in particular for Figure 3 and Figure 4 The base retainer mentioned and discussed earlier. However, due to the importance of this embodiment, it is described in detail in the accompanying drawings.

[0121] Preferably, the fixing plate surface 3f of the fixing plate 3 is supported or contacted at its periphery by the plate support protrusion 2'v, and the plate surface 3h of the fixing plate 3 is supported or contacted by the seal 12. The seal 12 is preferably disposed on the lower compensating plate 3', especially the plate support bracket 2'p. The seal 12 seals the peripheries of the plates 3,3' to each other while still allowing the two plates 3,3' to bend.

[0122] In this regard, it is mentioned again that the curvature is very small, that is, the radius of curvature is very large. A point on any surface of one of the two plates 3,3' will move only a few nanometers, a few micrometers, and in very rare cases a few millimeters in the z-direction. This small curvature also allows such a delicate structure to maintain mechanical stability. In particular, this allows the plate support protrusions 2'v to be implemented with great precision.

[0123] The substrate 7 is secured by the substrate fixing member 4. In a particular case, the figure shows a portion of the substrate fixing member 4 extending through the cavity 5. These portions are particularly implemented to be extendable. They can be, for example, flexible hoses, feed tubes, or any other conduits capable of evacuating the area between the substrate 7 and the fixing plate 3. In particular, there are multiple outlet openings on the substrate fixing member 3, arranged particularly symmetrically around a center. This allows the pin 11 to be located at the center of the fixing plate 3, which has a positive impact on bonding characteristics.

[0124] Figure 6b A preferred third embodiment according to the invention is shown in a side view in its final state. An adjusting device 6 (in this particular case, a non-central opening, valve, or nozzle) pumps fluid into the cavity 5. The fixed base 3 is bent according to the invention. The compensating plate 3' is preferably bent into the groove 13, which is fully inserted into the compensating plate 3'.

[0125] The bending is therefore concentrated in the central portion of the compensating plate 3', and ensures that a smaller moment and / or a smaller force acts mechanically on the plate support 2', in this case specifically by the plate support protrusion 2'v, the seal 12, and the plate support support 2'p (see...). Figure 6a (Enlarged view in the image). Through this additional structural improvement according to the invention, mechanical feedback to the fixing plate 3 is completely prevented, or minimized to a negligible degree.

[0126] List of reference numerals 1,1',1'',1''' Basement retainer 2,2' Plate support 2'v plate support protrusion 2'p plate support bracket 3. Fixing plate 3' Compensation plate 3f Fixed plate surface 3h,3h' Cavity plate surface 4. Base Fixing Components 5. Cavity / Intermediate Space 6,6',6" Adjustment device / bending device 7. Base 11-pin 12. Seals, especially sealing rings 13 Grooves 14 Electrical insulation components 15. Circuit.

Claims

1. A substrate retainer (1',1'',1''',1'''') for a bent substrate (7), comprising: - A fixing plate (3) for fixing the base (7); - Bending device (6,6',6") for bending the fixed plate (3), The fixed plate (3) is characterized in that the curvature of the base (7) can be adjusted in a targeted manner, wherein the reaction force generated when the fixed plate (3) is bent can be compensated by at least one compensation device (3').

2. The substrate retainer (1', 1'', 1''', 1'''') according to claim 1, wherein, The compensation device (3') refers to a flexible compensation plate.

3. The substrate retainer (1', 1'', 1''', 1'''') according to claim 1, wherein, The thickness of the fixing plate (3) is variable.

4. The substrate retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The fixing plate (3) is installed in a hinged manner.

5. The base retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The uniform curvature of the substrate (7) is adjustable.

6. The substrate retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The back side of the fixing plate (3) is shaped in such a way that a uniform curvature is produced.

7. The substrate retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The fixing plate (3) is thicker at the center than at the edge.

8. The substrate retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The fixing plate (3) is constructed to taper toward the edge.

9. The base retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 3, wherein, The fixing plate (3) is constructed symmetrically with respect to the center.

10. An apparatus having at least one base retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 9.

11. A bonding device having at least one substrate retainer (1', 1'', 1''', 1'''') according to any one of claims 1 to 9.

12. A method for bonding two substrates (7), wherein Includes the following steps, wherein: - The first base is fixed to the first base holder (1', 1'', 1''', 1'''') according to any one of claims 1 to 9, wherein; - Secure the second base to the second base holder (1', 1'', 1''', 1'''') according to any one of claims 1 to 9; - Align the bases (7) with each other; - To bend at least one of the bases (7); - This makes the substrate (7) come into contact; The feature is that the curvature of at least one of the substrates (7) is adjusted in a targeted manner.

13. The method according to claim 12, wherein, The curvature of at least one base (7) is uniformly adjusted.

Images