Mark field and method and apparatus for identifying positions - Patents.com

Abstract

To provide a device and a method for measuring a substrate that enable more accurate or more efficient identification of a position of a structured or feature portion on the substrate.SOLUTION: A mark (1) includes at least two location marks (2) that contain information about a location of each location mark (2) within a mark field (4) and at least one position mark (3) assigned or assignable to one of the location marks (2). In addition, in a device for identifying an X-Y-position of a structural feature (11c) of a structured part (11) arranged on a substrate (7), the X-Y-position is identifiable relative to the mark field (4) fixed with respect to the substrate.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The invention relates to a mark field according to claim 1, to a device for determining the XY-position of structural features of a structured part arranged on a substrate according to claim 8, and to a corresponding method according to claim 9.

[0002] In industry, knowledge of the position of a structure on a substrate is of crucial importance. Of particular interest is the difference between the actual, real position of the structure and its ideal target position. To determine the actual position of the structure, a coordinate system can be introduced, with which the position of the structure can be expressed. In most cases, the coordinate system is object-fixed, i.e., assigned to the substrate. This coordinate system will be referred to below as the substrate coordinate system.

[0003] However, in order to be able to measure all the structures, a relative movement must be performed between the substrate and the measurement system, in particular an optical system with a camera. This is necessary because not all the structures are within the field of view of the measurement system. If all the structures to be measured were within the field of view of the measurement system, then a relative movement between the measurement system and the substrate would of course not be necessary.

[0004] Relative motion is usually achieved by active motion of a substrate holder on which the substrate is fixed, so that delicate optical systems do not have to be moved. In this case, the position of the substrate holder must be determined very accurately so that the distance traveled by the substrate holder can be determined. That is, the position of the substrate holder must be expressed with respect to a spatially fixed coordinate system.

[0005] It is also possible to determine only the path traveled by the substrate holder between two points, which certainly eliminates the need for a spatially fixed coordinate system, but still requires a very sophisticated control system to be able to determine the distance traveled very accurately.

[0006] The above-mentioned methods of the prior art require relatively expensive and complex electromechanical systems to be able to measure the position or path of the substrate holder and thus the position of the structure on the substrate surface. Furthermore, the travel path of such equipment is considerable. Due to the corresponding structure size, even the smallest temperature fluctuations have an effect on the thermal expansion of the components used and thus on the component size.

[0007] In order to measure structures on the substrate surface of the substrate that are not simultaneously within the field of view of the optical system, a relative movement between the substrate and the optical system must be performed to successively bring these structures into the field of view of the optical system. In most cases, a substrate holder, on which the substrate is fixed, moves, while the optical system remains stationary. During the movement, the position of the substrate holder must be continuously tracked. This means that a reference system is required, relative to which the position of the substrate holder is displayed. The position indication of the substrate holder, and thus of the substrate, must be performed very accurately, especially in the nanometer range. This accurate position indication, especially over a distance of several centimeters, requires very precise and therefore expensive measurement systems, especially interferometers.

[0008] It is therefore an object of the present invention to provide an apparatus and a method for measuring a substrate, which allows a more accurate and / or more efficient determination of the position of structuring or structural features on the substrate.

[0009] The above problem is solved by the features of claims 1, 8 and 9. Advantageous developments of the invention are defined in the dependent claims. Any combination of at least two of the features described in the description, claims and / or drawings is also within the scope of the invention. When ranges of values ​​are indicated, values ​​lying within the stated limits are also disclosed as limit values ​​and any combination can be claimed.

[0010] The idea behind this invention is that Markfield - at least two location marks, each containing information about the location (orientation) of the location mark within the mark field; - at least one position mark assigned or assignable to one of the location marks, which determines the XY-position (coordinates) of a structural feature of the structured part on the substrate, in particular independently of the movement or position of the substrate holder; The purpose is to establish a system.

[0011] The measurement of the structured features of the substrates according to the invention allows for a more accurate and efficient bonding process between the two substrates in subsequent process steps, in particular. If the measured structured feature position does not equal the desired structured feature position, an adjustment of at least one of the two substrates is carried out, in particular before and / or during the bonding process. In other words, the substrate pair is preferably formed according to a selection criterion. In particular, according to the invention, the location of the structured feature, in particular the rotational position, is determined from the two XY-positions or from other features of the location mark and / or position mark.

[0012] Furthermore, the invention makes it possible to determine the expansion or deformation of the structuring from the two XY-positions or from other features of the location and / or position marks.

[0013] One particularly independent aspect of the invention is to associate or relate the individual XY-positions of structural features of a structured portion on the substrate surface of a substrate to position marks on the surface of the substrate opposite the substrate surface, and in particular to determine their spacing in the X and / or Y directions. For this purpose, location marks are used, in particular in addition to the position marks. By using position marks and location marks of this type, it is no longer necessary to determine or track the position of the substrate holder with high precision, in particular by means of technically complex or cost-intensive measuring systems, in particular optical ones. A rough determination of the current position is performed, in particular by reading and interpreting the location marks. A more precise determination of the current position can be performed, in particular by means of additional position marks, preferably assigned to the location marks.

[0014] The invention thereby particularly describes a method and device for identifying, in particular measuring, preferably position measuring, structured or structural features without the need to determine the position of the substrate holder and thus the position of the substrate relative to a (separate) reference system.

[0015] Another, particularly independent, core of the present invention is to provide a method and an apparatus which in particular makes it possible to completely omit the use of a spatially fixed reference system relative to which the XY-position of the substrate holder is indicated or measured.

[0016] The basic idea is, in particular, to form a mark field on a surface that is preferably arranged or can be arranged to be located opposite the substrate surface on which the structuring or structural features are to be measured.

[0017] The mark field has two particular properties: each mark in the mark field is coded in such a way that the measuring system, in particular the optical system, can deduce the location of the mark. Once this location is known, the device can carry out a highly accurate position determination, preferably by means of a position mark assigned to each location mark.

[0018] Once the mark field is known and two optical systems are used that are calibrated to one another, the structuring / structural features on the substrate surface of the substrate to be measured can then be related to the mark (and vice versa), which allows calculations, in particular calculation of spacing changes, to be made without the need for a spatially fixed external reference system.

[0019] A spatially fixed reference system, relative to which the position of the substrate holder has to be noted, is no longer required, i.e. it is no longer necessary to track the position of the substrate holder optically by means of an interferometer or mechanically by means of a step counter. Therefore, in a development of the invention, no means are used or the device is equipped with for detecting (in particular for continuously detecting) the position of the substrate holder, apart from the means disclosed according to the invention, in particular as described below.

[0020] Another important aspect of the present invention is to reduce or substantially avoid distortion of the mark field and / or position marks, among other things.

[0021] mark A mark is understood in the broadest sense in the present invention as an optically and / or topographically detectable structure (or structural feature of the structure), the structure (or structural feature of the structure) or its position, preferably at least its XY-position, being detectable and thus determinable by a measuring device. Measuring devices for detecting the structure / structural feature and thus determining its position are in particular: -optical systems, in particular cameras, -contact systems, especially AFM, It may be.

[0022] The marking preferably consists of at least one of the materials listed below: -metals, especially Cr,Al,Ti,Cu,Ag,Au,Fe,Ni,Co,Pt,W,Pb,Ta,Zn,Sn, -Alloys, especially Metal alloys, metal-nonmetal alloys, -ceramic, -plastic, -Semiconductors, especially Compound semiconductors, especially GaAs,GaN,InP,InxGa1-xN,InSb,InAs,GaSb,AlN,InN,GaP,BeTe,ZnO,CuInGaSe2,ZnS,ZnSe,ZnTe,CdS,CdSe,CdTe ,Hg(1-x)Cd(x)Te,BeSe,HgS,AlxGa1-xAs,GaS,GaSe,GaTe,InS,InSe,InTe,CuInSe2,CuInS2,CuInGaS2,SiC,SiGe, Semiconductors, especially Ge, Si, α-Sn, fullerene, B, Se, Te.

[0023] Preferably, the marks are detected optically, and therefore optical measurement will be described below. The marks consist in particular of location marks and position marks. The location marks are preferably codable or coded marks, i.e. information carriers, according to the invention. The position marks are in particular used exclusively to determine highly accurate positions, in particular XY positions.

[0024] In particular, the location marks and the position marks assigned to them are detectable simultaneously within the field of view of the optical system used in each case. Preferably, the location marks, in particular each location mark, are arranged relatively close to the assigned position mark so that simultaneous detection is guaranteed.

[0025] According to an advantageous embodiment of the invention, the location mark can comprise one or more position marks.

[0026] The location marks are in particular smaller than 5 mm x 5 mm, preferably smaller than 1 mm x 1 mm, more preferably smaller than 0.1 mm x 0.1 mm, especially preferably smaller than 0.01 mm x 0.01 mm, most preferably smaller than 0.001 mm x 0.001 mm. Particularly preferably, the location marks have a width or diameter of 20 μm to 200 μm.

[0027] The position marks are in particular smaller than 0.1 mm x 0.1 mm, preferably smaller than 0.01 mm x 0.01 mm, more preferably smaller than 0.001 mm x 0.001 mm, especially preferably smaller than 0.0001 mm x 0.0001 mm, most preferably smaller than 0.00001 mm x 0.00001 mm.

[0028] The location marks and / or position marks are preferably part of a pattern generated in a computer. The positions of the location marks and position marks in the digital pattern can be considered ideal. The actual location marks and position marks are produced by, among other things, layering, masking, etching, and development techniques. The positions of these actual location marks and position marks deviate from the desired ideal positions, particularly based on processes and equipment that may involve errors. These deviations are preferably minimal and in the nanometer range. Therefore, the smaller the deviation between the ideal position and the actual position, the higher the accuracy of the location marks and position marks. The deviation is particularly preferably less than 1 μm, preferably less than 500 nm, more preferably less than 250 nm, particularly preferably less than 50 nm, and most preferably less than 10 nm.

[0029] Another aspect of the invention is to accommodate manufacturing imprecision of the mark field carrier, in particular the marks, particularly the position marks that should be produced with high precision. Therefore, the device has a mark field with position marks that are not produced with high precision, which allows for a significant reduction in production costs.

[0030] Nevertheless, to be able to utilize a position mark field that provides a highly precise position, the target position mark field is stored and memorized, particularly in a computer. The position of the position mark in the computer can be considered ideal, while the actual position (actual position) of the created position mark field may deviate therefrom. In the adjustment process, the mark field of the mark field carrier is measured (the actual position is determined), and the relative position between the ideal position mark in the computer and the actual position mark on the mark field carrier is determined and stored.

[0031] From there, for each actual position mark, a corresponding correction is calculated relative to the ideal position mark, particularly in the form of a vector for the respective position. In this way, it is possible to correlate the structure on the substrate with the actual position marks on the mark field carrier, and on the other hand, to correlate the actual position marks with the ideal position marks in the computer. This idea significantly reduces the manufacturing costs of the mark field carrier, especially by allowing for relatively inaccurate manufacturing of the mark field, thus providing economic advantages.

[0032] According to the invention, each location mark is individualized within the mark field. This individualization eliminates the possibility of confusing different location marks, so that by detecting each location mark it is possible to deduce the XY-coordinate area of ​​the location mark on the mark field. The coordinate system of the mark field is specifically called the mark field coordinate system. The location marks preferably have the following characteristics: -QR code, - barcode, -Geometric, especially three-dimensional figures, strings of symbols, in particular strings of letters and / or numbers, preferably binary codes, -image, One or more of:

[0033] The location marks are in particular information carriers. Preferably, each location mark is coded with an XY-position that indicates at which position in the raster (grid pattern) this location mark is located, i.e. in which XY-coordinate area this location mark is located.

[0034] The position marks can be configured as simple or complex structures. The detailed shape of the position marks is not described here, as it is known in the prior art. In the drawings, the position marks are particularly indicated by crosses. The position marks are preferably made identically to alignment marks commonly used in the prior art, and preferably have the same appearance. This allows the techniques used in the prior art for analyzing alignment marks to also be used for analyzing the position marks.

[0035] In a particularly preferred embodiment of the invention, the position mark surrounds, in particular encircles, the location mark, in which case the position mark is configured in particular as a circle, a rectangle, an octagon or any other geometrical figure that can be easily recognized and evaluated by software.

[0036] Mark Field The mark field comprises a set of marks, namely location marks and position marks, which are preferably arranged with high symmetry relative to one another. It is particularly important for the present invention that the position marks are created with high accuracy relative to one another. The location marks assigned or assignable to the position marks are arranged so that both are preferably simultaneously present in the field of view of the optical system. The location marks are used primarily to read the approximate location position (orientation) observed by the optical system, which will be referred to hereinafter simply as location. Preferably, the relative position between each location mark and the assigned position mark is the same. This facilitates the programming of the evaluation algorithm and thus facilitates the search for location marks and / or position marks in the mark field as soon as they are present in the field of view of the optical system.

[0037] In one particularly preferred embodiment, the location mark is surrounded, in particular surrounded, in particular all around, by the position mark.

[0038] This allows the manufacturing precision of the location marks to be lower than that of the position marks, thereby minimizing the manufacturing costs for the mark field.

[0039] If the mark field is made up of location marks and position marks that are fused together, preferably all marks in the mark field are made with high precision, since each mark is both a location mark and a position mark, i.e. has both functions.

[0040] Preferably, the marks are arranged with uniform spacing between the location marks within any, particularly symmetrical, raster. Adjacent location and / or position marks are preferably arranged at equal intervals on the mark field. In particular, there are more than 10 × 10 marks, preferably more than 100 × 100 marks, more preferably more than 1,000 × 1,000 marks, particularly preferably more than 10,000 × 10,000 marks, and most preferably more than 100,000 × 100,000 marks within the mark field. The spacing between adjacent location marks is, in particular, smaller than the width and / or height or diameter of the location marks. Preferably, the ratio of the spacing to the width and / or height or diameter of the location marks is smaller than 1, more preferably smaller than 0.5, and even more preferably smaller than 0.1.

[0041] Preferably, the location marks encode an XY-position within the raster, so that when detecting the location marks it is possible to deduce for each raster area that has just been detected by the detection means, in particular the optical system or systems. It is possible to encode additional information within each location mark, for example the location of an assigned position mark relative to the location mark.

[0042] As a caveat, the marks do not have to be on a highly symmetrical raster. The distribution of the marks can be arbitrary, as long as the spacing relationship (vector or XY-spacing) between the position marks is known and each location mark can be associated with its corresponding position mark. A distribution of marks on an asymmetrical raster represents a slightly degraded embodiment.

[0043] The mark field is preferably arranged as close as possible to the substrate surface on which the structure to be measured or the XY position of which is determined according to the invention is located. On the other hand, the structures forming the mark field should be protected from damage. The distance between the structure to be measured and the mark field carrier is preferably 0.1 mm to 100 mm, preferably 0.25 mm to 75 mm, more preferably 0.5 mm to 50 mm, particularly preferably 1 mm to 30 mm, and most preferably 5 mm to 20 mm.

[0044] In particular, the mark field is arranged on the side of the mark field carrier facing away from the substrate and is thus not in direct contact with the substrate in order to protect it from mechanical loads and abrasion. The mark field can also be covered with a transparent coating to protect it from mechanical and / or chemical influences.

[0045] Markfield Carrier A mark field carrier according to the invention is one or more components on which a mark field is / is provided.

[0046] According to a first embodiment of the invention, the substrate holder itself is the mark field carrier: the mark field is present on one of the two surfaces of the substrate holder, preferably on the fixing surface on which the substrate is fixed.

[0047] If the mark field is present on the fixed surface, the substrate holder, at least below the mark field, is preferably made at least partially transparent for the electromagnetic radiation observing the mark field.

[0048] If the mark field is present on a surface located opposite the fixing surface, the substrate holder may be opaque.

[0049] In a second, particularly preferred embodiment according to the invention, the mark field carrier is a separate component which can be fixed in or against the substrate holder and is therefore quickly exchangeable.

[0050] Preferably, in this case too, the mark field is provided on a fixed surface, said component being at least partially transparent to the electromagnetic radiation used. This configuration allows the mark field carrier to be manufactured separately from the substrate holder, which increases flexibility and makes replacement easier. Furthermore, production costs can be reduced.

[0051] According to one embodiment of the present invention, the substrate holder is configured so that a mark field carrier can be inserted into the substrate holder and is supported only at its periphery. In this particular embodiment, the mark field carrier is configured as thick as possible, so that bending resistance is as high as possible and distortion of the position marks is minimized, preferably completely eliminated. The thinner the mark field carrier is, which is supported only at its periphery, the more it is bent by the force of gravity. This bending results in an extension of the mark field carrier surface facing the direction of gravity. This also results in compression of the mark field, which reduces the accuracy of determining the XY position.

[0052] In another embodiment of the present invention, the substrate holder is configured such that the mark field carrier can be inserted therein and is supported not only from the periphery but also from below by support columns, particularly centrally-oriented support columns. The support columns, in particular, minimize curvature of the mark field carrier. Preferably, the support columns are at least partially transparent to the electromagnetic radiation used to detect the XY position of the structured feature. If the support columns are opaque, no correlation can be formed between the marks in the mark field and the structured feature on the substrate surface along the surfaces hidden by the support columns.

[0053] The transmittance of the marked field carrier and / or the support is in particular higher than 10%, preferably higher than 25%, more preferably higher than 50%, particularly preferably higher than 75%, most preferably higher than 95%.

[0054] The problem of bending can be addressed, inter alia, by making the mark field carrier as thick as possible, in particular, the thickness of the mark field carrier is greater than 1 mm, preferably greater than 2 mm, more preferably greater than 5 mm, particularly preferably greater than 20 mm, and most preferably greater than 30 mm. The thicker the mark field carrier, the greater the bending resistance of the mark field carrier and the less likely it is to be deformed by bending.

[0055] The substrate may have any arbitrary shape, but is preferably circular. The diameter of the substrate is particularly standardized in the industry. For wafers, common industrial diameters are 1 inch, 2 inches, 3 inches, 4 inches, 5 inches, 6 inches, 8 inches, 12 inches, and 18 inches. However, embodiments according to the invention can in principle handle any substrate, regardless of its diameter.

[0056] The mark field carrier and / or the mark field in particular have a diameter and / or a peripheral contour that is approximately equal to the diameter of the substrate.

[0057] In a particular embodiment, the diameter of the mark field carrier is larger than the diameter of the substrate, in particular larger than 1.01 times the diameter of the substrate, preferably larger than 1.05 times, even more preferably larger than 1.1 times, especially preferably larger than 1.2 times, most preferably larger than 1.2 times.

[0058] According to one development of the invention, the support columns are as transparent as possible. Preferably, the support columns themselves are manufactured from a material that is completely transparent to the electromagnetic radiation used. To provide as much visibility as possible for the optical system used, the support columns can also be provided with as many slots and holes as possible. To improve the reduced support effect again, the slots and holes can be closed by transparent inserts, particularly in a form-fitting and / or flush manner.

[0059] The mark field carrier is preferably at least partially made from at least one of the following materials: -metals, especially Cu,Ag,Au,Al,Fe,Ni,Co,Pt,W,Cr,Pb,Ti,Ta,Zn,Sn and / or -Plastics, especially Elastomers, especially Viton (material) and / or Polyurethane and / or Hypalon (material) and / or Isoprene rubber (material) and / or Nitrile rubber (material) and / or Perfluoro rubber (material) and / or Polyisobutene (material), Thermoplastic elastomers and / or -semiconductor materials, especially Compound semiconductors, GaAs,GaN,InP,InxGa1-xN,InSb,InAs,GaSb,AlN,InN,GaP,BeTe,ZnO,CuInGaSe2,ZnS,ZnSe,ZnTe,CdS,CdSe,CdTe ,Hg(1-x)Cd(x)Te,BeSe,HgS,AlxGa1-xAs,GaS,GaSe,GaTe,InS,InSe,InTe,CuInSe2,CuInS2,CuInGaS2,SiC,SiGe, Semiconductors, especially Ge, Si, α-Sn, fullerene, B, Se, Te, -Glass, especially metallic glasses, Non-metallic glasses, especially organic non-metallic glasses, Inorganic non-metallic glasses, especially Non-oxide glasses, especially halide glasses, chalcogenide glasses, Oxide glasses, especially phosphate glass, Silicate glasses, especially aluminosilicate glass, lead silicate glass, Alkali silicate glasses, especially Alkali-alkaline earth silicate glasses, Borosilicate glass, Borate glasses, especially Alkali borate glass, quartz, -ceramic, -Minerals, especially sapphires.

[0060] The mark field carrier preferably comprises: -cylindrical, - (preferably) rectangular parallelepiped, However, the mark field carrier can in principle have any arbitrary shape.

[0061] The mark field carrier is preferably made from a material with a very low coefficient of thermal expansion so that temperature fluctuations do not lead to distortion of the mark field carrier and therefore the mark field.

[0062] If the mark field carrier is made of a material with a low thermal expansion coefficient, the mark field carrier is preferably mounted in such a way that expansion of the mark field surface is prevented, i.e., the mark field surface cannot expand despite possible temperature fluctuations or deviations. This condition is solved structurally, in particular, by mounting the mark field carrier in a component, in particular a substrate holder, which itself consists of a material with a low thermal expansion coefficient.

[0063] It is desirable that the coefficient of thermal expansion of the mark field carrier be as small as possible to prevent distortion of the mark field carrier due to temperature differences or distortion of components that hinder the expansion of the mark field carrier. -4 K -1 Smaller, preferably 5 x 10 -5 K -1 Smaller, more preferably 10 -5 K -1 Smaller, particularly preferably 5×10 -6 K -1 Smaller, particularly preferably 10 -6 K -1 Smaller, most preferably 10 -7 K -1 Smaller than.

[0064] When the mark field carrier is in contact with the substrate to be measured, the mark field is preferably arranged on the mark field carrier as close as possible to the structured portion of the substrate to be measured. By appropriately minimizing the distance between the mark field and the structured portion to be measured, possible optical errors that may arise due to the alignment of the optical axes of the optical systems that are calibrated to one another are minimized.

[0065] In embodiments in which the mark field carrier and the substrate holder are different components or groups, the fixing elements may be present on the substrate holder and / or on the mark field carrier. If the fixing elements are present on the mark field carrier, a control connection is preferably provided between the substrate holder and the mark field carrier for controlling the fixing elements on the mark field carrier.

[0066] The fixing elements are used to hold the substrate. The fixing elements may be any of the following fixing elements: - mechanical fastening means, in particular clamps; vacuum fixing means, in particular vacuum fixing means having a plurality of vacuum strips which can be individually controlled or which are connected to one another; - Electrical fastening means, in particular electrostatic fastening means; - magnetic fastening means, adhesive fastening means, in particular Gel-Pak fastening means, adhesive fastening means, in particular with a controllably movable surface; It may be one or more of:

[0067] The clamping means can be controlled, in particular electronically. Vacuum clamping is a preferred form of clamping. The vacuum clamping preferably consists of a plurality of vacuum channels, which are exposed to the surface of the sample holder. The vacuum channels are preferably individually controllable. In a technically more feasible application, several vacuum channels are grouped into vacuum channel segments, which can be controlled individually and thus evacuated or filled independently of one another. The vacuum channel segments are preferably configured in the shape of a ring.

[0068] A special form of clamping is realized by a low-contact substrate holder, which consists of a number of individual, particularly symmetrically distributed, raised pins. Such substrate holders are also called pin chucks. The space between the raised pins can be evacuated, thereby simultaneously serving as a vacuum clamping mechanism. Advantageously, only the raised pins come into contact with the substrate, thus resulting in relatively low stress and contamination on the clamped substrate. A further advantage is that a low-contact substrate holder minimizes distortion of the clamped substrate, which is an advantage for measuring structured portions of the substrate. A further advantage is that a low-contact substrate holder allows for a substantially uniform clamping of the substrate. An embodiment of such a substrate holder is disclosed in WO 2015 / 113641, to which reference is made in this regard. Such low-contact substrate holders are preferably at least largely opaque so that the mark field according to the present invention resides on a surface remote from the substrate fixing surface.

[0069] In another, less preferred embodiment of the invention, the substrate on which the structure to be measured is located is itself the mark field carrier. The mark field is arranged on the substrate surface opposite the substrate surface with the structure to be measured. This unpreferred embodiment has the following disadvantages: First, a mark field must be formed for each substrate, which leads to additional effort and costs. Second, forming the structure on one side of the substrate and the mark on the other side of the substrate leads to production problems and, in some cases, distortion. Third, substrates usually have a low bending resistance, which can also lead to distortion of the mark field.

[0070] It is therefore advantageous, according to one development of the invention, to have the mark field preferably clearly separated from the substrate to be examined, ie the mark field is not arranged on the substrate itself.

[0071] Device The device according to the invention comprises a mark field carrier, a substrate holder and at least two optical systems. The mark field carrier is preferably part of the substrate holder (and vice versa). Insofar as the present specification speaks of the substrate holder or the mark field carrier, these are considered as a unit or are used synonymously.

[0072] The two optical systems are constructed and arranged facing each other. The optical axes of the two optical systems are preferably calibrated to each other as well as possible, and are preferably oriented so as to be parallel or aligned. For the calibration of two optical systems oriented to each other, see WO 2014 / 202106. The optical systems are translatable in the x-direction, y-direction, and / or z-direction and / or rotatable about three spatial axes, each preferably arranged perpendicular to each other. These degrees of freedom are used for the calibration of the optical systems. Once the two optical systems are calibrated to each other, preferably no relative movement between them is performed any more. The optical systems are fixed relative to each other during the inventive determination of their XY-positions.

[0073] Just to be clear, we disclose the possibility of coupled movement of two optical systems calibrated to each other. Preferably, the optical systems are mechanically coupled to each other via a kind of U-shaped coupling, so that they are again fixed relative to each other during the inventive determination of their XY-position. However, it is more preferable to mechanically decouple both optical systems from each other. Preferably, the optical systems are mechanically decoupled as best as possible or at least damped from the frame or surface over which the substrate holder is moved, in order to minimize vibrations.

[0074] The frame is preferably mechanically decoupled or at least damped from the optics to avoid vibration transmission as completely as possible.

[0075] method Before the decisive method step according to the invention of determining the XY position, both optical systems are in particular calibrated as best as possible to one another.

[0076] The optimal calibration method is to orient the optical axes of both optical systems so that they are congruent, i.e., coincident with one another. Achieving this state can be technically difficult or even impossible. However, it is preferable to at least attempt to approximate this state as closely as possible.

[0077] Another important step for optimally calibrating the two optical systems with respect to each other is to overlap the depth of field ranges of the two optical systems so that the intersection of the depth of field ranges allows simultaneous detection of the mark field and the structure to be measured. This is only possible if the depth of field ranges of both optical systems are at least equal to or greater than the distance between the mark field and the structure to be measured, which is hereby disclosed as an advantageous embodiment of the present invention. In particular, in the case of thick substrates or mark field carriers in which the mark field is located far away from the structure to be measured, the mark field is focused by one optical system and the structure by the other optical system, i.e., brought into the respective depth of field ranges of the respective optical systems.

[0078] Prior to the actual method according to the present invention, it is preferable to calibrate both optical systems with respect to each other so that possible errors caused by the tilting of both axes can be taken into account when determining the XY position. The present invention is directed to the production of a mark field carrier with a mark field that is as versatile as possible and can be used for any type of structure on any substrate. This is desirable, especially in view of the high production costs required for such mark field carriers. Therefore, it is preferable to produce a mark field that is as independent as possible of the structure to be detected on the substrate.

[0079] In a particular embodiment of the present invention, multiple position marks can be assigned to one location mark, resulting in a very dense field of position marks. Alternatively or additionally, multiple position marks can be arranged in the field of view of the optical system. The field of view is preferably rectangular, most preferably square, i.e., the number of pixels per unit dimension of the field of view is constant. The number of position marks per unit dimension of the field of view is then at least 1, preferably more than 3, even more preferably more than 5, particularly preferably more than 7, and most preferably more than 10. The multiple position marks according to the present invention ensure that at least one (preferably at least two) position marks can always be found in the field of view, even if the next location mark is not yet visible. Therefore, the density of the position marks can be higher than the density of the location marks. The density of the position marks can be the same as the density of the location marks, preferably twice, more preferably five times, particularly preferably ten times, and most preferably 100 times the density of the location marks.

[0080] In particular, the method according to the present invention, and the embodiment in which several position marks are simultaneously present in the field of view, allow for averaging of the position marks, preferably compensating for manufacturing errors of the position marks. Averaging results in correspondingly averaged virtual position marks, which can then be used as position marks for measuring structuring on the substrate surface. Assume that four position marks are simultaneously present in the field of view, all of which are located at the corners of a square. By determining the positions of the position marks, the center of the square can be calculated, which is then used as the new position mark. This new position mark does not actually exist, but can be calculated by a computer, stored, and, if necessary, written into the digital image. It is not important for the method according to the present invention whether real or calculated position marks are used for the method according to the present invention.

[0081] The method according to the invention can be used in particular to determine deviations between actual and target parameters of a structured area on the substrate surface or of at least one structural feature of the structured area (i.e. in particular production errors). Possible production errors are, for example, a photolithography process that results in slightly oblique exposure, an etching process that results in poor edge quality, etc. Furthermore, deviations can also be a posteriori distortions, in particular distortions due to temperature fluctuations. In particular, the structured area can be -Rotational errors and / or - Translational errors and / or -scaling errors and / or -Residual error The rotation error is understood to be an error in the global and / or local rotation of the structured part relative to its ideal target position. The translation error is understood to be an error in the global and / or local translation of the structured part relative to its ideal target position. The scaling error is understood to be an error in the global and / or local scaling of the structured part relative to its ideal target position. This error is also referred to in the art as "runout". "Runout" is characterized by an increase in the error, particularly as the radius increases. In most cases, this error is the result of thermal expansion, which acts more strongly at the edge of the substrate than in the region near the center. The residual error refers to all other types of error that lead to a deviation between the target and the actual structuring. The effect of the actual structuring differing slightly from the target structuring is referred to below as an initial error or "incoming error".

[0082] Further or additional errors may occur during subsequent processes, in particular during the bonding process. The embodiments according to the present invention are particularly suitable for measuring the structure before further processes, in particular the bonding process. Measuring the actual state of the structure, in particular immediately before the bonding process, is essential for guaranteeing and ensuring the conformity of the structure on the two substrates to be bonded. However, it should be noted that the method according to the present invention can also be used to measure the structure in relation to the mark field according to the present invention after the bonding process has been carried out. For this purpose, the substrate through which the structure is to be examined must be transparent to the electromagnetic radiation used in each case so that the structure at the bonding interface can be recognized. Glass substrates can also be used. If a suitable substrate is transparent to infrared radiation, infrared radiation can also be used for measuring the structure. The substrate can also be thin enough to be transparent to visible light. For silicon, this is the case when the thickness is less than 10 μm, preferably less than 5 μm, more preferably less than 3 μm, especially preferably less than 2 μm, and most preferably less than 1 μm.

[0083] Therefore, as an independent invention, the present invention also discloses a method for identifying the XY-positions of structured portions / features of two substrates to be connected in a subsequent bonding step.

[0084] In an optional method step, the optical axes of the two optical systems used are calibrated to one another, the calibration of both optical systems being preferably carried out by means of a calibration substrate.

[0085] The calibration substrate has a thickness approximately equal to the distance between the structured portion of the substrate to be measured and the mark field. The calibration substrate has two calibration marks, one on each side. These calibration marks should be as closely related to one another as possible, i.e., they should be directly superimposed. In other words, the lateral displacement between the calibration marks should be minimized. In a particularly preferred embodiment of the present invention, this type of calibration mark is produced by forming a through-hole, in particular a through-hole, or more preferably a through-etching, from one substrate surface to the other. The holes in the substrate surfaces then coincide with one another throughout the thickness. This method is referred to below as the drilling method. In a first calibration method according to the present invention, the upper optical system focuses on the upper calibration mark, and the lower optical system focuses on the lower calibration mark. Since the optical axes of the two optical systems generally do not coincide with one another, the calibration marks combined in one image also do not coincide. The distances dx1 and dy1 between the calibration marks in the x and y directions are measured and stored.

[0086] Then, the substrate is rotated 180° and the calibration marks are measured again. The distances dx2 and dy2 between the calibration marks in the x and y directions are measured and stored.

[0087] In a further calibration step, the error values ​​dx and dy are calculated: dx=dx1+dx2 dy=dy1+dy2 The values ​​dx and dy thus determined are thus the (double) total error consisting of the (double) lateral displacement of the calibration mark and the (double) optical error: dx = (double) lateral displacement x + (double) optical error x dy = (double) lateral displacement y + (double) optical error y By using the already mentioned optimum production methods for the calibration marks, in particular the drilling method, the lateral displacement can be reduced to practically zero, and the values ​​dx and dy represent the (double) optical errors: (2x) optical error x=dx (2x) optical error y=dy If the lateral displacement is not very small, the lateral displacement must be determined in a different way and then subtracted: (2x) optical error x = dx - (2x) measured lateral displacement x (2x) optical error y = dy - (2x) measured lateral displacement y Optical errors in the x and y directions ultimately result in Optical error x = (double) optical error x / 2 Optical error y = (double) optical error y / 2 The optical errors in the x and y directions need only be calculated once, as long as the optical systems are not subsequently moved further relative to one another. They can then be used to correct the measured x and y spacings between the structured features on the substrate surface and the corresponding position marks in the mark field by the optical errors. The optical errors are preferably stored as vectors and are denoted by the letter F in the following text.

[0088] In a further method step according to the invention, the substrate is fixed to a substrate holder and to a mark field carrier having a mark field. Preferably, the substrate and the mark field carrier are two separate components. In particular, the substrate is fixed directly to the mark field carrier, which in turn is fixed to the substrate holder.

[0089] In a subsequent method step according to the present invention, the structured features on the substrate surface, in particular all of the structured features, are moved and measured. A first, in particular an upper optical system, focuses on the structured features of the substrate, while a second, in particular a lower optical system, captures a corresponding area of ​​the mark field, which has at least one location mark and at least one position mark. The two generated images can be digitally superimposed, thus producing a superimposed image that can be preferably digitally evaluated by software.

[0090] As soon as the location mark is within the field of view of the lower optical system, information about the XY-coordinate field of the location mark is evaluated. This means that the device now knows in what rough position the substrate holder, and thus the substrate, is located relative to the optical system. Preferably, the position mark is centered relative to the lower optical system, so that it is located in the center of the field of view of the optical system. Alternatively, the optical system can be centered relative to a characteristic structural feature of the structured part to be measured. Preferably, the position mark is centered because several characteristic structural features of the structured part should be measured relative to the position mark so that the rotational position of the structured part can also be determined.

[0091] Centering of the position mark, although preferred, is not essential to the practice of the present invention, as absolute positioning is not required when measuring the distance between the position mark and the distinctive structural feature of the structured portion.

[0092] It is important that at least one characteristic structural feature of the structure is measured relative to the position mark. For example, in the case of a rectangular structure, the upper left corner can be selected. In the case of a rectangular structure, it is preferable to measure all four corners relative to the position mark. Measuring is understood to mean determining at least two values, namely the horizontal distance dx and the vertical distance dy, each relative to the same position mark.

[0093] In particular, the image and / or the determined data, in particular the location data of the location marks and the position data of the position marks and the structures or structural features, are stored in a computer. This method step is performed for any number, preferably for all, of the structures on the substrate.

[0094] In a further method step according to the invention, after obtaining the XY-position data of the detected, particularly all characteristic structural features of the structure, the determined XY-positions are determined relative to the respective ideal positions (target positions). A particularly ideal structure, preferably a mark field, is suitable as a reference. This allows the deviation of the characteristic structural features, i.e., the difference between the target state and the actual state, to be determined.

[0095] The precise, in particular mathematical, determination of the XY-position or deviation is carried out taking into account in particular one or more of the following points: - The axes of the mark field do not coincide with the axes of the substrate coordinate system. The ideal position marks of the mark field in the computer are not aligned the same as the real position marks of the mark field on the mark field carrier. The deviation can be measured and stored. The correlation between the positions of the real position marks in the mark field and the positions of the real structuring on the substrate can be determined as described herein. -Ideal position of the mark field in the computer The correlation between the position of the mark and the ideal position of the structuring part in the computer can be calculated since the data is always available and does not have to be measured first. Optical errors can be calculated from the data using values ​​determined in the calibration process. The data from the above enumeration always allows the calculation of the deviation of the real structuring on the substrate from the ideal structuring in the computer.

[0096] In one process step, the axial orientation of the mark field coordinate system relative to the substrate coordinate system is determined, in particular the correction is performed by a relative displacement between the substrate and the mark field carrier, in particular an active movement of the substrate.

[0097] However, since it is not advantageous to move the substrate again after it has been fixed to the mark field carrier, the correlation between the coordinate systems is determined in particular mathematically. The directions of the axes can be determined by measuring a number of position marks on the mark field carrier, in particular a number of position marks along two mutually perpendicular directions.

[0098] The same considerations apply to the axes of the substrate. From these data, a rotation matrix R is calculated. The displacement between the two coordinate origins is represented in particular by the vector v. This shows that a correction term for the correlation between the position marks on the mark field carrier and the structuring on the substrate is added to the equation x 基板 =R×x マークフィールド +v. The corresponding inverse notation is x マークフィールド =R -1 ×x 基板 -v. Those skilled in the art have the necessary matrix algebra knowledge.

[0099] Since this process step involves measuring multiple position marks in the mark field or multiple structuring areas on the substrate, this process step cannot be clearly assigned in time without any problems. The more data there is, the more accurately the correlation between the two coordinate systems can be performed. Preferably, a mathematical algorithm based on the least squares method is used to determine the rotation matrix and the displacement vector. In the following text, it is assumed that the axis orientations of all coordinate systems involved always have the same origin and the same orientation relative to each other.

[0100] The following convention is used to explain the mathematical calculation process: index i represents ideal, index r represents real, index S represents structure, and index M represents mark. A difference vector is always denoted by a lowercase r. A difference vector is calculated in particular from a position vector pointing to an end point, and rarely from a position vector pointing to a start point. Accordingly, as is the mathematical convention, the index of the end point is listed first. The position vector is shown far below and is not included in the diagrams described. As an example, the vector r to be calculated by the present invention is Sr,Si This is a discrepancy vector that represents the deviation in position between the real structure and the ideal structure.

[0101] In a further process step, the positions of the ideal position marks in the mark field in the computer are compared with the positions of the actual position marks in the mark field on the mark field carrier. This measurement results in a table in the computer storing the actual positions of the position marks and / or the ideal positions of the position marks and / or their difference vectors. These difference vectors are calculated using the following formula: Mr,Mi The discrepancy vectors thus obtained yield a vector map, which in the following text will be referred to as the mark field error vector map.

[0102] In a further process step, the positions of the actual position marks of the mark field on the mark field carrier are compared with the positions of the structure on the substrate. By measuring the actual positions of the position marks of the mark field and the positions of the structure on the substrate, a table is obtained in which the actual positions of the position marks and / or the positions of the structure on the substrate and / or difference vectors are stored in a computer. These difference vectors are calculated by r Sr,MrThe difference thus determined results in a vector map, which in the following text will be referred to as the actual mark structure difference vector map, which is the process step that forms the core idea of ​​the present invention, namely the association of the position marks of the mark field carrier with the structure of the substrate.

[0103] In a further process step, the positions of the ideal position marks of the mark field in the computer are compared with the ideal positions of the structuring portion in the computer. By reading the ideal positions of the position marks of the mark field in the computer and the ideal positions of the structuring portion in the computer, a table is obtained in the computer in which the ideal positions of the position marks in the computer and / or the ideal positions of the structuring portion in the computer and / or difference vectors are stored. These difference vectors are calculated by r Si,Mi The difference thus determined produces a vector map, which in the following text will be referred to as the ideal mark structure difference vector map. In particular, this process step only needs to be performed once for each combination of ideal mark field and ideal structure field.

[0104] As a result, Sr,Si =r Mr,Mi +r Sr,Mr -r Si,Mi -F, where F is the optical error vector calculated in the calibration process. Preferably, F is constant for all points, i.e., F represents a constant as a function of location rather than a vector field.

[0105] The present invention allows for multiple measurements to be taken in order to improve the quality of the measurements by statistical averaging. A new measurement can be performed quickly using the existing data and the location of the location marks. Detection proceeds most quickly if it is performed step by step from mark to mark. This makes it unnecessary to use a measurement system that specifically continuously tracks the absolute position of the substrate holder or the relative displacement of the substrate holder.

[0106] In an optional, but particularly desirable, further method step according to the invention, a rotation of the substrate, in particular a rotation of exactly 180°, is carried out in order to measure all previously measured structures anew. The detection of the structures can be carried out quickly, since they have already been associated with position-coded location marks in the previous detection step. By using an algorithm, possible optical errors caused by possible obliqueness of the optical axis of the optical system can be corrected.

[0107] All technically possible combinations and / or permutations and intermixings of the functional and / or material parts of the apparatus and associated changes in at least one of the method steps or methods are considered to be disclosed.

[0108] To the extent that apparatus features are disclosed herein and / or in the following description of the drawings, the apparatus features should also be considered to be disclosed as method features, and vice versa.

[0109] Further advantages, features and details of the invention can be seen from the following description of preferred embodiments, taken in conjunction with the drawings. [Brief explanation of the drawings]

[0110] [Figure 1a] 1 is a detailed view of a first embodiment of a mark according to the invention, comprising a location mark and a position mark; [Figure 1b]FIG. 2 is a detailed view of a second embodiment of a mark according to the invention, comprising a location mark and a position mark. [Figure 2] 2A and 2B are a plan view and a cross-sectional view along the section line AA of an embodiment of a mark field carrier according to the present invention having a mark field; [Figure 3] 1A and 1B are a plan view and a cross-sectional view along the cutting line AA of one embodiment (first embodiment) of a substrate holder according to the present invention. [Figure 4] 2A and 2B are a plan view and a cross-sectional view taken along the cutting line AA of an embodiment (second embodiment) of a substrate holder according to the present invention. [Figure 5] 2A and 2B are a plan view and a cross-sectional view taken along the cutting line AA of an embodiment (third embodiment) of a substrate holder according to the present invention. [Figure 6] 2A and 2B are a plan view and a cross-sectional view taken along line AA of an embodiment (fourth embodiment) of a substrate holder according to the present invention. [Figure 7] 1A and 1B show a plan view and a cross section of a substrate according to the invention with structuring and mark fields; [Figure 8] 1 shows a cross-sectional side view of an embodiment of the device according to the invention during a method step of detection according to the invention; [Figure 9] FIG. 10 is a partial side view of the detection step. [Figure 10] FIG. 10 is a partial side view of the detection step. [Figure 11] FIG. 10 is a partial side view of the detection step. [Figure 12] FIG. 10 is a partial side view of the detection step. [Figure 13] FIG. 10 is a partial side view of the detection step. [Figure 14a] FIG. 10 shows a superimposed image generated from the detection step at a first rotational position in a first position. [Figure 14b] FIG. 10 shows a superimposed image generated from the detection step at a second rotational position in the first position. [Figure 15a]FIG. 10 shows a superimposed image generated from the detection step at a first rotational position in a second position. [Figure 15b] FIG. 10 shows a superimposed image generated from the detection step at a second rotational position in a second position. [Figure 16] FIG. 10 shows a vector field generated by the present invention to illustrate the deviations determined by the present invention. [Figure 17] FIG. 10 shows the resulting discrepancy vectors.

[0111] In the drawings, the same components or components having the same functions are given the same reference numerals.

[0112] 1a shows a mark 1, which consists of a location mark 2, in particular a QR code, and a position mark 3. In one particularly preferred embodiment according to the invention, the location mark 2 is also used as a position mark, so that the position mark 3 is omitted and included within the location mark 2.

[0113] The location mark 2 is configured so that the information can be read by any system, in particular an optical system. The exemplary QR code contains the readable position information (1,11), from which it can be seen that this location mark is located in the first row, eleventh column of the grid of the mark field 4 shown in Figure 2.

[0114] FIG. 1b shows a particularly preferred mark 1', which consists of a location mark 2, in particular a QR code, and a position mark 3'. In this particular embodiment, the location mark 2 is smaller than the position mark 3' and is surrounded by the position mark 3' in particular all around. An evaluation algorithm can recognize the shape or contour of the position mark 3' and determine the exact position of the position mark 3'. In the specific case, this exact position is the center of an octagon. The center of the octagon can be found, for example, by software, in that an algorithm fits a mathematical octagon to the contour of the octagon obtained from the measured image and determines the center from this mathematical octagon. Such algorithms are known to those skilled in the art and will not be described further here.

[0115] In the following description of the drawings, the mark 1 shown in FIG. 1a will be used as an example to further explain the concept according to the present invention.

[0116] 2 shows a plan view and a side view of a mark field carrier 5 having a mark field 4, which consists of a plurality of marks 1 arranged, in particular highly symmetrically with respect to one another. The mark 1 shown in FIG. 1a is located in the first row, eleventh column relative to the illustrated origin of the coordinate system 6 for the mark field carrier 5, and is therefore located at grid position (1,11). Counting here starts at zero.

[0117] The mark field 4 is preferably present on a mark field carrier surface 5o of the mark field carrier 5. The mark field carrier 5 is preferably transparent so that the mark field 4 is detectable through the mark field carrier 5 from the rear side 5r of the mark field carrier. The mark field carrier 5 preferably has fixing means 12 to which a substrate 7 (see FIG. 8) can be fixed, the fixing means 12 being preferably formed in the form of a vacuum channel.

[0118] 3 shows a first embodiment of a substrate holder 8, in particular a transparent substrate holder 8, which is simultaneously formed as a mark field carrier 5. In this case, the mark field 4 is preferably present on the substrate holder surface 8o as well as the fixing means 12. In a further preferred embodiment according to the invention, the substrate holder 8 is opaque and the mark field 4 is arranged on the rear side 8r of the substrate holder.

[0119] FIG. 4 shows a second embodiment of a substrate holder 8′. The substrate holder 8′ accommodates a mark field carrier 5. In other words, unlike the first embodiment, the substrate holder 8′ is not a mark field carrier itself. The mark field carrier 5 is preferably transparent. The mark field 4, like the fixing means 12, is present on the mark field carrier surface 5o. The mark field carrier 5 is not supported in the center and can therefore bend downwards, particularly due to gravity, but also due to forces acting from above. This type of bending can compress the mark field 4 on the mark field carrier surface 5o and should therefore preferably be reduced. This is achieved by making the mark field carrier 5 particularly thick.

[0120] Figure 5 shows a third embodiment of a further improved substrate holder 8''. The substrate holder 8'' has support posts 10 that support the mark field carrier 5, so that bending is largely avoided. Preferably, the support posts 10 are themselves transparent.

[0121] FIG. 6 shows a fourth, further improved embodiment of the substrate holder 8'". The substrate holder 8'" has a post 10 with a through-hole 14, which in particular extends tapered. Individual mark field carriers 5', in particular formed as inserts, can be accommodated or fixed in the through-holes 14, which carry the mark fields 4. Fixing means 12 are present in this particular embodiment, for example, in the substrate holder 8'".

[0122] In particular, since only the support posts 10 have the mark fields 4, no marks are provided in the empty areas between the support posts 10. This allows the substrate holder 8''' to be made very fine and lightweight, and yet can be easily manufactured. The substrate holder 8''' has a high rigidity despite its relatively small thickness. Furthermore, the mark field carrier 5', and thus the mark fields 4, can be relatively easily replaced.

[0123] FIG. 7 shows a fifth, less preferred embodiment of the mark field carrier 5'', which is here formed by the substrate 7 itself. The substrate 7 has a structure 11 on one side (the mark field carrier back side 5r'') and the mark field 4 on the opposite side. This special embodiment only makes sense if it can be ensured that the mark field carrier back side 5r'', on which the mark field 4 is located, is not deformed.

[0124] FIG. 8 shows a substrate holder 8′ with a mounted and fixed transparent mark field carrier 5, on which a substrate 7 with a structured portion 11 is fixed by fixing means 12.

[0125] A first, in particular upper, optical system 13 detects, with a field of view (shown enlarged), the substrate surface 7o on which the structure 11 is arranged. The first optical system 13 is focused on the structure 11.

[0126] A second optical system 13', specially calibrated with and preferably congruent with the first optical system 13, detects the mark field carrier surface 5o with the mark field 4 through the transparent mark field carrier 5. The second optical system 13' is focused on the mark 2.

[0127] The detected images are superimposed, in particular digitally superimposed, to produce one superimposed image from which the distances dx and dy between one (or more) structural features 11c (here the upper left corner of the structured portion 11) and the highly accurate position mark 3 are determined in relation to the XY-coordinate system.

[0128] 8, the corners (structural features 11c) of the structure 11 are not aligned with the position mark 3, and the spacings dx and dy are not zero. Furthermore, the structure 11 is slightly rotated relative to the reference alignment of the position mark 3.

[0129] The location mark 2 can also be seen from the field of view or superimposed image of the optical systems 13, 13', and the location mark 2 can provide information about the rough position.

[0130] From the detection of the plurality of structural features 11c, the rotational state and / or deformation of the structured portion 11 can be determined.

[0131] 9 to 13 show further detection steps in different cases, which are distinguished as follows:

[0132] Figure 9: The optical axes of both optical systems 13 are aligned. Furthermore, the characteristic structural features 11c of the structure 11 are located directly above the position marks 3 that are important for the position measurement. This results in an ideal superimposed image. A further feature is that the density of the structure 11 on the substrate surface 7o is equal to the density of the position marks 3 on the mark field carrier surface 5o. Preferably, a mark field carrier 5 that can be used for various substrates 7 with different densities of structure 11 is configured.

[0133] The density of the marks 1 is, according to the invention, in particular higher than the density of the structured portion 11. This ensures that at least one mark 1 in the region of the structured portion 11 and / or structural feature 11c is located within the field of view of the optical system 13, 13'.

[0134] Figure 10: The optical axes of both optical systems 13 are coincident with one another. In this case, the characteristic features 11c of the structure 11 are not located directly above the position marks 3, which are important for the position measurement. Any discrepancies that occur in the superimposed image are solely attributable to the misalignment between the position marks 3 and the structure 11 and are not due to optical errors. A further feature is that the density of the structure 11 on the substrate surface 7o is not equal to the density of the position marks 3 on the mark field carrier surface 5o.

[0135] It can also be seen from this figure that translational offsets do exist between the structure 11, more precisely the characteristic features 11c of the structure 11, and the position marks 3, but that these are the same for all (shown) superimposed images. This means that to obtain the overlap shown in Figure 9, it is only necessary to displace the substrate 7 relative to the mark field carrier 5 (naturally only for every other structure 11, since the structure density in Figure 10 is only half that of Figure 9).

[0136] FIG. 11: The optical axes of the two optical systems 13, 13' are not coincident with each other, nor even parallel to each other. Therefore, it cannot be assumed that the characteristic structural features 11c of the structured area 11 coincide with the respective position marks 3 in the superimposed image (even if they are precisely positioned on top of each other). The skew of the optical axis, as well as variations in the thickness of the substrate 7, wedge errors of the substrate 7, etc., lead to non-ideal superimposed images even under ideal conditions. To correct these optical errors, a second measurement of all structures is performed by performing a 180° rotation (as described above), and the optical errors primarily due to the skew of the optical axis are calculated from the average of the positions of the characteristic structural features 11c of the structured area 11 thus determined.

[0137] Figure 12: The density of the structure 11 is different from the density of the position marks 3. The distinctive structural features 11c do not coincide with the position marks 3 and the optical axes of the optical systems 3 do not coincide with each other and are not parallel to each other. By eliminating the errors from the optical axes as explained with respect to Figure 11, we are left with the superimposed image shown in Figure 10.

[0138] FIG. 13: This embodiment shows a preferred case according to the invention. Again, the densities of the structured areas 11 and the position marks 3 are different. The oblique optical axis introduces an optical error into the superimposed image. The optical error is calculated by a 180° rotation and a second, complete measurement of all structured areas. Furthermore, the structured areas 11 are shifted significantly to the left. The surface may have been distorted by certain processes and / or this area may have experienced a stronger thermal expansion due to thermal loading. This means that this displacement of the structured areas 11 is no longer related to the overall displacement of all structured areas 11 relative to the mark field 4, which is specifically attributable to the displacement of the substrate 7 as a whole relative to the mark field 4. This displacement of the structured areas 11 is location-specific and inherent. It is especially important that the underlying mark field 4 is highly symmetrical and that this high symmetry is maintained.

[0139] The following figures are used to further explain possible error causes and the countermeasures taken by the method according to the invention in relation to the error causes, so that they can be determined and evaluated when identified.

[0140] 14a shows an overlapping image of the structured portion 11 with the position mark 3 and location mark 2 at a rotational position of 0° at position (11,1). The distance dx(11,1), 0° and dy(11,1), 0°, between the position mark 3 and the characteristic structural feature 11c of the structured portion 11 are detected.

[0141] 14b shows a superimposed image of the structured portion 11 with the position mark 3 and location mark 2 at a rotational position of 180° at a first position (11,1). The distance dx(11,1), 180° and dy(11,1), 180°, between the position mark 3 and the characteristic structural feature 11c of the structure 11 are detected.

[0142] From the values ​​dx(11,1),0° and dx(11,1),180° or the values ​​dy(11,1),0° and dy(11,1),180°, the errors caused by the skew of the optical axis and other error sources can be calculated in the x or y direction, and as a result the net deviation between the position mark 3 and the characteristic feature 11c of the structured portion 11 can be determined (calculated).

[0143] Figures 15a and 15b show another structured portion 11 in a second position (12,1), again at two different rotational positions (0° and 180°). Again, errors caused by optical axis skew and other error sources can be calculated in the x- or y-direction. Figures 14 and 15 reveal that the horizontal and / or vertical offset between the position mark 3 and the distinctive structural feature 11c can be significantly different at different positions. These differences are the result of, among other things, distortion, expansion, etc.

[0144] Figure 16 shows the vector field. This vector field shows, in a simplified manner, how the structure 11 (not shown here) is deformed as a function of location (position). The magnitude of the arrows indicates increasing deformation from the center outwards. This schematically indicates that the structure is being stretched towards the edge of the substrate 7. The length of the arrows increases. This schematically indicates that the translational deviation is magnified towards the edge. This is therefore a classic runout error. None of the arrows have a tangential component, so no rotational deviation is discernible. In reality, the vector field determined by the present invention has a more complex appearance.

[0145] FIG. 17 shows a schematic diagram of an excerpt from an image superposition of ideal and real structured elements and ideal and real position marks at a certain location. This illustration is used to mathematically explain the relationship between various quantities that can be calculated and measured. The exact illustration of the location marks has been omitted for clarity. The coordinate axes of the coordinate systems of the ideal and real planes have already been matched to each other, so that all coordinate systems have the same orientation and origin. The relationships of all other difference vectors are visible, except for optical errors, which are not explicitly shown and are only mentioned in formulas. The positions of the ideal position mark 3i and the ideal structured element 11i exist in the computer. The positions of the real position mark 3r and the real structured element 11r are measured. The difference vector r according to the present invention is calculated. Sr,Mr can be measured. The discrepancy vector r Si,Mi can be calculated directly from the computer data; no measurements are required. The discrepancy vector r Mr,Mi can also be measured. From the acquired data, the discrepancy vector r Sr,Si That is, the deviation of the position of the actual structured portion 11r from the position of the ideal structured portion 11i is calculated. [Explanation of symbols]

[0146] 1,1' mark 2 Location Mark 3,3',3i,3r position marks 4. Mark Field 5,5',5'' Markfield carrier 5o,5o',5o'' Markfield carrier surface 5r,5r'' Markfield carrier back side 6 Object-fixed coordinate system 7. Circuit Board 7o Substrate surface 8,8',8'',8''' PCB holder 8o Substrate holder surface 8r Back side of board holder 9 Fixed Elements 10 posts 11,11i,11r structure 11c Distinctive structural features 12 Fixing means 13,13' optics 14 Penetration

Claims

1. 1. An apparatus for bonding two substrates by identifying the XY-position of a structural feature (11c) of a structured portion (11) arranged on a substrate (7) before the bonding process of the two substrates, the apparatus comprising: The XY-position can be determined relative to a mark field (4) fixed with respect to the substrate (7), the mark field (4) having a plurality of marks (1), each of which includes one location mark (2) containing position information (1, 11) and at least one position mark (3) located outside the location mark (2); The mark field (4) is arranged on a substrate holder (8) to which the substrate (7) is fixed, The substrate holder (8) has a fixing surface to which the substrate (7) is fixed, the mark (1) of the mark field (4) is located on the opposite side of the substrate (7) from the structural feature (11c) of the structured portion (11), the position marks (3) are provided on the fixing surface of the substrate holder (8) and serve to identify, before the bonding process, the X-Y positions of the structural features (11c) of the structured portion (11) provided on the surface of the substrate (7) facing away from the substrate holder (8); During the bonding step, the structural features (11c) of one substrate are bonded to the structural features (11c) of the other substrate in a mating manner.

2. 2. The device according to claim 1, wherein the position mark (3) is provided at one corner of the rectangular location mark (2).

3. 2. The device according to claim 1, wherein the position mark (3) is formed so as to surround the location mark (2) in an annular shape.

4. 4. The device according to claim 1, wherein the mark (1) is provided over the entire surface of the fixing surface of the substrate holder (8).

5. 5. The device according to claim 1, wherein the marks (1) are uniformly spaced from one another within any raster.

6. The apparatus of claim 5 , wherein the raster is symmetric.

7. 7. The device according to claim 1, wherein adjacent marks (1) are equally spaced apart.

8. 8. The device according to claim 1, wherein the mark field (4) comprises at least 10x10 marks (1).

9. A method for determining the XY-position of a structural feature (11c) of a structured portion (11) arranged on a substrate (7) before a bonding process of two substrates and then bonding the two substrates, comprising: Before the bonding step, the X-Y-position is determined relative to a mark field (4) fixed with respect to the substrate (7), the mark field (4) having a plurality of marks (1), each of which includes one location mark (2) containing position information (1, 11) and at least one position mark (3) arranged outside the location mark (2), the mark field (4) being arranged on a substrate holder (8) to which the substrate (7) is fixed, the substrate holder (8) having a fixing surface to which the substrate (7) is fixed, the position mark (3) being arranged on the fixing surface of the substrate holder (8), and the marks (1) of the mark field (4) being located on an opposite side of the substrate (7) from the structural feature (11c) of the structuring portion (11); determining the XY-position of a structural feature (11c) of a structure (11) on the side of the substrate (7) facing away from the substrate holder (8) relative to the position mark (3); During the bonding step, the structural features (11c) of one substrate are bonded in conformity with the structural features (11c) of the other substrate.

10. 10. The method according to claim 9, wherein the position mark (3) is provided at one corner of the rectangular location mark (2).

11. 10. The method according to claim 9, wherein the position mark (3) is formed so as to surround the location mark (2) in an annular shape.

12. 12. The method according to any one of claims 9 to 11, wherein the mark (1) is provided over the entire surface of the fixing surface of the substrate holder (8).

13. 13. Method according to any one of claims 9 to 12, characterized in that the marks (1) are uniformly spaced from one another within any raster.

14. The method of claim 13 , wherein the raster is symmetric.

15. 15. The method according to any one of claims 9 to 14, wherein adjacent marks (1) are equally spaced apart.

16. 16. Method according to any one of claims 9 to 15, wherein the mark field (4) comprises at least 10x10 marks (1).

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