A holding device for a disc-shaped member for X-ray inspection, and a method for clamping the member in the holding device.

Abstract

The present invention provides a holding device for disc-shaped members, which allows the edge region of the member to be inspected without interference caused by the member's holding, when the member is inspected within an X-ray inspection system, and a method for clamping the member in the holding device. [Solution] In an X-ray inspection system equipped with an X-ray tube and a detector, the holding device as part of the manipulator allows the position and orientation of the wafer 10 to be corrected by radial clamps 1, each of which applies force in the direction of the wafer's center within the wafer's plane, allowing access to the X-ray tube from one side of the wafer and securing free space for the beam cone of the X-ray tube on the other side of the wafer. The wafer is placed on the support surface 17 in a pre-aligned manner, and then radial alignment and angle alignment of the wafer are performed using the radial clamps 1, and the wafer is fixed in the axial direction by axial clamps 2.

Description

Technical Field

[0001] The present invention relates to a disc-shaped member, particularly a holding device for a wafer, which is part of a manipulator of an X-ray inspection system. The present invention also relates to a method for clamping the member to the holding device at its edge. For simplicity, hereinafter, the term "wafer" is generally used for all possible disc-shaped members, but this should not be construed restrictively, and particularly in the claims, the term "member" is used to clarify that the patent encompasses all disc-shaped members from its description.

Background Art

[0002] During the implementation of high-resolution computed laminography of a wafer on which an inspection object is placed by an X-ray inspection system, in order to achieve the highest possible magnification for the inspection object, the X-ray tube needs to be moved very close to the wafer. Due to the spatial spread of the X-ray tube, the corresponding area (above or below the wafer) must be accessible even beyond the lateral edge of the wafer. Furthermore, the X-ray beam needs to be able to pass through the wafer without being obstructed so that the image of the inspection object is not overlaid by interference caused by the wafer holder. This means that there is no material that obstructs the X-ray beam (along the direction of the X-ray) other than the wafer between the detector and the X-ray tube. Additionally, the wafer needs to be moved by a holding device that is fixed for inspection along a corresponding trajectory through the X-ray beam. There should be no play between the holding device and the wafer that allows for relative movement that changes the trajectory. The holding device is part of the manipulator and is usually movable in the X and Y directions within the plane of the manipulator.

[0003] Most wafer holders disregard the requirements of such X-ray technology and computer laminography. A common solution involves operating from the underside on a wide surface using vacuum technology, which inevitably means that the vacuum technology beneath the wafer must also be irradiated. The contrast is very large compared to the structure being inspected on the wafer, resulting in defects and structures within the inspected object becoming unclear. As an alternative, ring holders exist, in which case the ring has a significant width, and its depth, due to the required distance between the X-ray tube and the wafer, severely limits the magnification. Furthermore, there are wafer holders that clamp the wafer across its outer diameter. In most cases, when the detector is tilted up to 60°, the mechanism or the jaw itself obstructs the transmission of the wafer (such holders are described, for example, in CN114603527B and CN117542790A). If the holder is located on the opposite side of the X-ray tube, shadows are cast by the laminography angle, reducing the usable inspection area to the center of the wafer. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Therefore, the object of the present invention is to provide a holding device for a disc-shaped member, which, when used, allows the edge region of the member to be inspected in an X-ray inspection system without interference caused by the holding of the member, and to provide a method for clamping the member at its edge region. [Means for solving the problem]

[0005] The problem is solved by a wafer holding device as part of a manipulator for an X-ray inspection system, having the features of claim 1 or claim 2 according to the present invention. The problem is also solved by a method having the features of claim 17. Advantageous embodiments are described in the dependent claims.

[0006] As described above, the present problem is a wafer holding device as part of a manipulator for an X-ray inspection system, the holding device comprising an X-ray tube and a detector, wherein the position and orientation of the member can be corrected by radial clamps, each of which exerts a force in the direction of the center of the member within the plane of the member, the holding device allows access to the X-ray tube from one side of the member, and the holding device ensures free space for the beam cone (Strahlenkegel) of the X-ray tube on the other side of the member, thereby achieving this by a holding device.

[0007] The problem can also be achieved by a wafer holder as part of a manipulator for an X-ray inspection system, wherein the holder has a support surface formed in a plane, the support surface extending at least partially along an annule having a stopper edge extending at least partially along the outer surface of a cylinder, the stopper edge extending perpendicular to the support surface and having a diameter slightly larger than the diameter of the wafer that the stopper edge will accept. This allows the wafer to be easily attached to the holder by being placed on the support surface. The holder also has a base extending outward from the outer surface of a cylinder, on which the support surface is provided. It also has a base extending outward from the outer surface of a cylinder, on which the support surface is located. This ensures sufficient space on the support surface when the wafer is placed. The holding device also includes at least three radial clamps, each of which is linearly movable between an open and locked position by a first displacement device, and each of which is linearly movable radially relative to the support surface by a radial control element. This allows the wafer to be positioned very precisely within the holding device, which is necessary for good reconstruction of the X-ray laminography process. The holding device also includes at least two axial clamps, each of which is movable between an open and clamped position by a second displacement device, and each of which is movable by an axial control element, and the movement of the axial clamps is performed radially and axially relative to the support surface. This allows for very precise positioning of the wafer on the holding device while minimizing the relative movement of the wafer to the holding device while the manipulator is moved. This achieves advantages in both X-ray inspection and 3D X-ray processes. These advantages include the ability to inspect peripheral areas, high magnification, and oblique radiography at large angles. The latter makes it possible to distinguish between different layers within the object being inspected. The holding device of the present invention ensures very good reconstruction within the framework of the X-ray laminography process.The fixed positioning of the wafer on the holding device is ensured by the fixed connection of the support surface, radial clamp, and axial clamp to the base. The holding device also has a cam ring, which has a control contour that is always in contact with the radial control element and the axial control element. This allows for easy and highly precise movement of the radial clamp and the axial clamp. The holding device also has a connection mechanism for connecting the holding device to the manipulator.

[0008] The holding device preferably has features of both claim 1 and claim 2.

[0009] In an advantageous improved configuration, the support surface is defined to extend at least partially along an annule having a stopper edge that extends at least partially along the outer surface of the cylinder, the stopper edge extending perpendicular to the support surface and having a diameter slightly larger than the diameter of the wafer that the stopper edge will accept, and the base extends outward from the outer surface of the cylinder. This allows the wafer to be easily inserted into the holding device and pre-centered, and the base and support surface are not located in the beam path during X-ray inspection.

[0010] As another advantageous improvement, the support surface is formed from individual surfaces formed within the region of the U-shaped connecting bars on the U-shaped clamp, and the free ends of the parallel bars of the U are fixedly connected to the base. This saves a large amount of material compared to forming the support surface over the entire surface, while achieving sufficient overall fixation of the wafer to the holding device, thereby preventing the wafer from shifting relative to the holding device while passing along the trajectory during inspection, which would cause deterioration of the inspection results. The U-shape of the clamp saves even more material than if the clamp were made solid. It is also possible to use a V-shaped clamp instead of a U-shape, in which case the support surface is formed within the region where the two bars of the V-shape meet, and the free ends of the two bars of the V-shape are fixedly connected to the base.

[0011] As another advantageous improvement, the axial clamps are defined to each have a support element on which the support surface is formed, and each clamp element is independently movable, wherein the clamp elements are radially movable, and the support elements are movable in a direction having an axial component, particularly around a horizontal rotation axis. This makes insertion easier, especially in designs where the X-ray tube is positioned above the holder and the wafer insertion space is limited, because the support surface can be set to a low position during insertion and then moved upward. Furthermore, this has the advantage that even with a distorted wafer, the wafer will be in a low position within the holder and will not protrude too far in the direction of the X-ray tube, and the axial clamps (if equipped with springs) have the advantage that the highest point of the wafer edge in the direction toward the tube is limited by the axial clamps because the springs bend toward the opposite side of the tube.

[0012] As another advantageous improvement, the axial control element of the axial clamp of the shaft cooperates with the support element, and the second displacement device further has an additional axial control element that cooperates with the clamp element. This means that there is no need to incorporate a complex mechanism in the second displacement device to simultaneously control the movement of the two individual components (the support element and the clamp element), but rather that the movement of each of the two individual components is controlled individually by a single axial control element, thereby allowing for the use of a simpler mechanism for each.

[0013] As another advantageous improvement, the radial clamp and / or the axial clamp are specified to be located within the free area between the two parallel U-shaped bars of the clamping device. This makes the device more spatially compact, and the clamps are also better protected against mechanical damage because they are located between the legs of the clamping device.

[0014] Another advantageous improvement is that there are exactly three radial clamps, of which exactly one radial clamp has a projection (nose) at its free end that has the shape of a portion of the cylindrical outer surface perpendicular to the support surface. By using exactly three radial clamps, the wafer can be precisely positioned on the holding device to a position where the trajectory will be aligned during subsequent wafer inspection, without causing over-determination. The projection, which is embodied as the rounded free end of one radial clamp, allows for precise angular alignment with respect to the central axis of the wafer when the projection is inserted into a notch at the edge of the wafer (which is generally present in wafers).

[0015] Another advantageous improvement is provided, where all free ends of the radial clamp and / or the axial clamp are provided with plastic ends that are detachably connected to the rest of the clamp. The use of resin ensures that the wafer is not damaged during positioning and securing to the holder, especially if the resin is sufficiently flexible. Because the ends can be detached from the rest of the clamp, if wear begins to occur on the (preferably flexible) resin ends, the ends can be easily replaced without having to replace the entire affected clamp. As an alternative to resin, soft nonferrous metals, rubber, silicone, or silicone rubber can also be used.

[0016] Another advantageous improvement is that there are exactly six axial clamps, each associated in pairs, with equal spacing between adjacent pairs, and / or radial clamps positioned between two axial clamps in a pair. By arranging these pairs at equal intervals, it is ensured that the wafer is well supported on the support surface. By positioning radial clamps between each of the two axial clamps in a pair (when the pairs are equally spaced), a star arrangement is achieved where each fixing point is positioned radially at 120°, resulting in highly reliable in-plane positioning of the wafer. This makes it easier to clamp distorted wafers (meaning the wafers are not spread out strictly in the same plane) on the holding device. The spatial proximity of the axial clamps to the radial clamps positioned between them allows even saddle-shaped or pringle-shaped distorted wafers to be gripped by their outer circumferential surfaces.

[0017] Another advantageous improvement is that the control contours for each radial clamp are identical, as are the control contours for each axial clamp. This ensures synchronous movement for each type of clamp. Alternatively, the clamps can be controlled asynchronously without any changes to their design. For example, when using radial clamps of different designs, if one of the radial clamps has a projection for inserting into a notch in the wafer (which allows the wafer to be positioned more accurately on the holding device), the radial clamp with this projection can be withdrawn from the notch immediately before axial clamping is performed using the axial clamp. This reduces material wear on the projection.

[0018] As another advantageous improvement, the second displacement device of the axial clamp is specified to be implemented as a slider-crank mechanism or a control link, respectively. This allows the axial clamp to move radially in the first part of its movement from the open position and axially in the second part of its movement to the clamping position, thereby increasing the space for inserting the wafer into the holding device in the initial stage and ensuring that the wafer is fixedly clamped in the holding device without the risk of damaging the wafer in the final stage.

[0019] As another advantageous improvement, it is specified that each axial clamp is pressed into its clamping position by a replaceable spring, and / or each radial clamp is pressed into its locked position by a replaceable spring. This allows the contact pressure at the clamping position of the axial clamp and the contact pressure at the locked position of the radial clamp to be adjusted according to the type of wafer being inspected, and the springs are easily replaceable if they wear out. Furthermore, this prevents distorted wafers and wafers that are not perfectly circular (i.e., have tolerances for diameter and roundness) from being subjected to excessive force by the clamp that could damage the wafer, or to excessive force that could cause the wafer to not be fixed in the holding device during inspection, resulting in image errors. Additionally, the spring-loaded axial clamp has the advantage that if the X-ray tube accidentally makes contact, the wafer can bend axially, thereby preventing damage or destruction of the wafer.

[0020] As another advantageous improvement, at least one load compensator is positioned on the base, the load compensator having a compensator control element, the compensator control element is always in contact with the control contour of the cam ring, and the control contour in the vicinity of the compensator control element is formed inversely to the control contour in the region of the radial control element and the axial control element with respect to the radial distance from the stopper edge of the support surface. This makes it possible to reduce the high loads on the axial and radial clamps caused by the additional spring force acting on each clamp. This suppresses abrupt movements during operation (especially during large load peaks), thereby suppressing wafer damage. It also allows for more delicate operation.

[0021] As another advantageous improvement, it is specified that a first stopper and a second stopper are formed to be fixed on the base, and a control lever is formed to be fixed on the cam ring, the control lever being movable between the first stopper and the second stopper. This makes it easier to find the end position when the cam ring is rotated manually or by motor to clamp or open a wafer. The stoppers, on the one hand, ensure that the cam ring is easily operated and opened, and on the other hand, provide a simple visualization of whether the clamp is in the polar position of each clamp (open and locked position for radial clamps, open and clamping position for axial clamps) and is properly fitted into those positions.

[0022] As another advantageous improvement, the first and second stoppers are specified to be physical devices. These are particularly preferred in manual movement because they are very simple and inexpensive to implement. When the cam ring is moved by a motor, it is advantageous to perform an additional check to determine whether the cam ring is actually in one of the stopper positions, thereby positioning the clamp to correctly secure the wafer, or to allow the wafer to be easily removed from or inserted into the holding device. For this purpose, an inductive proximity sensor is provided that is positioned to detect whether the cam ring is in one of the stopper positions.

[0023] As another advantageous improvement, the cam ring drive attached to the manipulator is specified to be partially engaged with the control lever of the cam ring via a drive lever in order to rotate the cam ring relative to the base and, in particular, to move the cam ring between the two stoppers. This means that there is no need for an operator to enter the radiation room where the X-ray inspection system is installed for radiation protection requirements, thereby allowing for faster gripping. Furthermore, the holding device according to the present invention is also suitable for a fully automated loading system for unmanned continuous operation.

[0024] As another advantageous improvement, the combination of the clamp and the base is designed so that there are no portions located outside an angular range exceeding 20° radially with respect to the member around the vertex, and this angular range extends from the lower plane of the clamp parallel to the plane of the member, and the vertex is defined as being located at the point where the central beam of the X-ray tube used for inspection intersects the plane at the outermost radial point of the X-ray tube during inspection. This makes it possible to inspect the entire wafer in the X-ray laminography process without any interfering members in the beam cone, even when the laminography angle is up to 60° and the X-ray beam aperture angle is 20°, except for the edge region where clamping is performed on the holding device. If a larger laminography angle is used during inspection, it is necessary to reduce the angular range of the clamp and base combination as an alternative; for example, if the laminography angle is 65° and the aperture angle is 20°, the angular range needs to be 15°. For smaller laminography angles, a larger angular domain is also possible as an alternative design, in which case the angular domain must be 90° - (laminography angle) - (half of the X-ray beam aperture angle). For example, if the laminography angle is 55° and the X-ray beam aperture angle is 20°, the angular domain is 25°, and if the laminography angle is 50° and the X-ray beam aperture angle is 20°, the angular domain is 30°, and so on.

[0025] This problem is also solved by a method having the features of claim 19. In the method of clamping a wafer according to the present invention, particularly in the method of clamping a wafer in a holding device as part of a manipulator of an X-ray inspection system, the member is placed on a support surface in a pre-aligned manner, and then the radial alignment and angular alignment of the member are performed by a radial clamp, and the member is axially fixed by an axial clamp. Thereby, it becomes possible to accurately align the wafer, and the wafer maintains a fixed position on the holding device even when the holding device moves during X-ray inspection, so that inaccuracy does not occur during inspection. Thereby, the wafer is accurately aligned on the holding device and can be fixedly clamped even while the holding device is moving during inspection, suppressing inaccuracy in data collection.

[0026] As an advantageous improvement, it is stipulated that the movement of the axial clamp is first performed in the radial direction and then in the axial direction. Thereby, it becomes possible for the axial clamp to be in a radially retracted position while the wafer is being inserted into the holding device, and as a result, there is more room during insertion.

[0027] As an advantageous improvement, first, the radial movement of the clamping element of the axial clamp is performed, and then the support element is moved with an axial component, particularly by rotation around the axis of rotation, until the member is axially fixed between the clamping element and the support element. Thereby, it becomes possible to secure more space axially while the wafer is being inserted into the holding device, which is particularly important in a design where the X-ray tube is arranged above the wafer. When the wafer is fixed between the support element and the clamping element, the wafer is moved upward there, thereby making it possible for the X-ray tube to move very close to the wafer, achieving the maximum magnification rate possible.

[0028] As another advantageous improvement, it is defined that the radial movement of the axial clamp is carried out simultaneously with the radial alignment of the member. Thereby, since the axial clamp moves during wafer positioning, the total time required for wafer insertion, positioning, and clamping is reduced.

[0029] As another advantageous improvement, it is defined that, in the axial clamp and / or the radial clamp, the maximum force acting on the wafer is limited by a spring force. By limiting the spring force of the axial clamp, it is possible to prevent the axial pressure on the wafer edge from becoming too large during clamping and causing damage to the wafer. The spring pressure should be large enough to fixedly hold the wafer at a predetermined position on the holding device, and at the same time, it is necessary to sufficiently limit the pressure so that it does not bend the wafer edge. This is particularly necessary in the case of a distorted wafer that deviates from an ideal flat shape in one plane. The same also applies to the spring force limitation of the radial clamp and the axial pressure on the wafer edge by the radial clamp.

[0030] Preferably, the method is implemented by the holding device of the present invention.

Brief Description of the Drawings

[0031] Further details and advantages of the present invention will be described in more detail below with reference to the exemplary embodiments shown in the drawings.

[0032] [Figure 1] FIG. 1 shows a perspective view of the holding device of the present invention. [Figure 1a] FIG. 1a shows an enlarged portion from a slightly different line of sight direction of FIG. 1. [Figure 1b] FIG. 1b shows an enlarged portion from a slightly different line of sight direction of FIG. 1. [Figure 2] FIG. 2 shows a schematic plan view of the holding device of FIG. 1. [Figure 3] FIG. 3 shows a view similar to FIG. 2 but seen from below, showing details of a manually movable cam ring and radial and axial clamps cooperating with them. [Figure 4] Figure 4 shows an enlarged view of Figure 3 in a motor-operated embodiment. [Figure 5] Figure 5 shows a perspective view of an enlarged section of the radial clamping and axial clamping regions of a further embodiment, in which the X-ray tube is positioned above the wafer. [Figure 6] Figure 6 shows a schematic longitudinal section including the substrate, wafer, X-ray tube, and axial clamp. [Figure 7a] Figure 7a shows a scaled-down version of Figure 6, which includes an additional detector. [Figure 7b] Figure 7b shows a magnified view of the region in Figure 6. [Figure 8] Figures 8a to 8d show schematic diagrams of the four stages of the operating principle of the axial clamp. [Figure 9] Figures 9a to 9c show schematic diagrams of the three stages of the operating principles of radial clamping and axial clamping in an X-ray inspection system in which the X-ray tube is positioned above the wafer. [Modes for carrying out the invention]

[0033] Figure 1 shows a holding device for an X-ray inspection system for inspecting a wafer 10 according to the present invention, which may be incorporated into a table-shaped manipulator 9 (not shown, see Figure 5) that is movable (horizontally) in the XY plane. The vertical rotation axis belonging to the manipulator 9 is aligned to be collinear with the central axis of the wafer 10 being inspected. Thus, the holding device according to the present invention is incorporated or integrated collinearly within the kinematic final object axis (in the direction of the stationary structure). Other components of the system (e.g., X-ray tube 21 (see Figures 6-8) and detector (see Figure 7)) are not part of the invention and are therefore not shown.

[0034] The holding device has a base 4 that is rotatable relative to the manipulator 9. Nine U-shaped clamps 3 protrude into an open internal space that functions as a receiving opening 29 (see Figures 1a and 1b) for the wafer 10 to be inspected. On each of these clamps 3, a support (partial) surface 17 (see Figures 3, 4 and 6-8) is formed within the area of ​​the U-shaped connecting bar. The support (partial) surface 17 is limited by a vertically extending stopper edge 18 (see Figures 1a and 1b). The free ends of two parallel bars of the clamps 3 are fixedly connected to the base 4. The wafer 10 held by the holding device is placed on the support surface 17 formed from the partial surfaces on the clamps 3.

[0035] Before being clamped, the wafer 10 is centered in the XY plane (horizontal plane) by three radial clamps 1 and fixed to the clamping device 3 by six axial clamps 2. Each radial clamp 1 is positioned between two axial clamps 2 that are equally spaced from it. The radial clamps 1 are positioned such that the angle between them is 120° with respect to the center point of the wafer 10 (see Figure 2). The six axial clamps 2 have a similar configuration, but the radial clamp 1 shown at the bottom of Figure 1 differs from the other two in that it has a protrusion 7 (see the description of the protrusion 7 in particular in Figures 1b and 2). Also, the mechanisms of the three clamps 1 and 2 shown at the bottom of Figure 1 can be seen from the rear side (below the base 4). In addition, a load compensator 8 can be seen at the bottom of Figure 1 between the mechanism of the left axial clamp 2 and the mechanism of the radial clamp 1 (see the description of Figure 3 for details).

[0036] Furthermore, the cam ring 6 is also equipped with two mechanical stoppers (a first stopper 11 and a second stopper 12), which function to allow the cam ring 6, which is rotatably positioned on the base 4 and controls the movement of the radial clamp 1 and the axial clamp 2, to be manually moved between two end positions.

[0037] Figure 1a shows a magnified view of the left-hand region of Figure 1, with a flatter viewing angle.

[0038] On the left side, an axial clamp 2 is visible, which is positioned between the two legs of the clamping device 3. The front end of the axial clamp 2 is configured as a clamping body 30, which presses the wafer 10 against the lower support surface 17 and clamps the wafer 10 in that position.

[0039] Also visible on the upper right is a radial clamp 1, which is also positioned between the two legs of the clamping device 3. The radial clamp 1 has a radial positioning surface 34 at its free end, which presses radially against the edge of the wafer 10 and works in cooperation with the other two radial clamps 1 (see Figure 1) to correctly position the wafer 10. A stopper edge 18 extending vertically (axially) is clearly visible on the clamping device 3, and a small gap is formed between the stopper edge 18 and the edge of the wafer 10, which allows the pre-positioned wafer 10 (in the case of automatic feeding) to be placed on the support surface 17 with some play before the final precise positioning by the three radial clamps 1 is performed. The same applies when the wafer 10 is manually placed on the support surface 17.

[0040] Figure 1b shows a magnified view of the upper right region of Figure 1, with a flatter viewing angle.

[0041] Here, the axial clamp 2 (right side) and the radial clamp 1 (upper side) are shown. The axial clamp 2 is no different from the one in Figure 1a, so it will not be described in detail here. However, the radial clamp 1 differs from the one in Figure 1a and the other radial clamps 1 shown below in Figure 1 in that it does not have a radial positioning surface 34, but instead has a projection 7, which fits into a notch on the edge of the wafer 10, thereby ensuring even more precise radial positioning of the wafer 10.

[0042] Both the radial positioning surface 34 and the projection 7 have an (axial) height, which in the exemplary embodiment is approximately 6 mm. This also enables fixed positioning even if the wafer 10 is distorted and its edge is not on a (horizontal) plane.

[0043] In Figure 2, the retaining device is schematically shown in a plan view, where the cam ring 6 extends below the radial clamp 1 and the axial clamp 2, along with their respective retainers. The rotational movement of the cam ring 6 relative to the base 4 is indicated by a double-headed arrow.

[0044] Furthermore, it can be seen that there are two different types of radial clamps 1. Two identical radial clamps 1 are positioned at the bottom of Figure 2. On the other hand, the upper radial clamp 1 has a projection 7 at its free end, which protrudes further than the free ends of the other two radial clamps 1. This projection 7 fits into the notch of the wafer 10, thereby fixing the precise angular position of the wafer 10 within the holding device and, consequently, the manipulator 9.

[0045] The six axial clamps 2 secure the wafer 10 to the holding device in a vertical direction (i.e., perpendicular to the drawing plane in Figure 2), so that the manipulator 9 cannot experience any (unexpected) positional changes (in any spatial direction). By using the six axial clamps 2, excellent fixation can be achieved even for distorted wafers 10 that are not strictly within a single plane.

[0046] In Figure 3 (where the wafer 10 is omitted for improved visibility, and instead the receiving opening 29 is visible), the apparatus is shown from below, and the design of the cam ring 6 and its position relative to the base and the clamping device 3, which includes the radial clamp 1 and the axial clamp 2, are schematically and clearly visible. The cam ring 6 has a control contour 13, which cooperates with radial control elements 14 and axial control elements 15 associated with the clamps 1 and 2. In the exemplary embodiment, the control elements 14 and 15 are each embodied as rollers, thereby reducing friction and the force required to rotate the cam ring 6. Each radial clamp 1 has a radial control element 14, and each axial clamp 2 has an axial control element 15. The control elements 14 and 15 are always in contact with the control contour 13 of the cam ring 6, and this contact is achieved, for example, by a spring (not shown), as long as the device is open (i.e., the wafer 10 is not clamped). When the device is closed (i.e., the wafer 10 is clamped), the control elements 14 and 15 can also be separated from the control contour 13. Depending on the position of the cam ring 6, the control elements 14 and 15 are positioned at various different radial positions. Changes in the radial position of the axial control elements 15 are converted into radial and axial movements of each axial clamp 2 by mechanisms associated with each axial clamp 2. These movements will be described in more detail later in relation to Figures 8a to 8d.

[0047] As the clamps pass through various diameter positions, the mechanisms associated with clamps 1 and 2 are activated.

[0048] The mechanism for the radial clamp 1 only needs to act on radial movement in the horizontal plane, so that the clamped wafer 10 collides at its edge with the respective free ends of the radial clamp 1 shown in the upper part of Figure 3 and the lower part of Figure 2. This can be achieved, for example, by a simple lever mechanism. The radial clamp 1 is spring-loaded, so that dimensional tolerances at the edge of the wafer 10 are compensated and the maximum force that can be applied to the wafer 10 by the radial clamp 1 is limited. With respect to the radial clamp 1 shown in the lower part of Figure 3 and the upper part of Figure 2, the projection 7 moves into the notch of the wafer 10 before the final axial fixing by the axial clamp 2 is performed (therefore, the angle alignment of the wafer 10 is clearly achieved (in particular, the radial inward movement of the radial clamp 1 with the projection 7 corrects the position and angle of the wafer 10)), and then is slightly withdrawn from the notch again. The radial clamp 1 moves from its open position, where it is as far as possible from the center of the wafer 10 being inspected, to its locked position (as described above). Thus, the holding device according to the present invention can provide higher positioning accuracy compared to the accuracy of an insertion device or manual insertion.

[0049] However, the mechanism of the axial clamp 2 is more complex because, when closed (i.e., clamped), the axial clamp 2 contacts the edge of the wafer 10, requiring it to first move radially and then vertically. For this purpose, a slider-crank mechanism (Schubkurbelgetriebe) or control link (Steuerkulisse), which is known in principle from the prior art, is used. The initial radial movement is to increase the free space when inserting the wafer 10 into the holding device, thereby reducing the risk of collision with the radial clamp 1, which could result in damage to the wafer 10. The individual movement stages of the axial clamp 2 are shown in Figure 8 and will be described in more detail later.

[0050] Three cam ring bearings 28 are formed on the cam ring 6, extending radially and spaced equally apart from each other. Guide rollers are positioned on these cam ring bearings 28, and these guide rollers hold the cam ring 6 in a ball bearing configuration. Alternatively, a gleiter may be present on the clamps 1 and 2, and the cam ring 6 may be guided via this gleiter.

[0051] Two stoppers on the cam ring 6 can be seen in the lower right section. The first stopper 11 abuts against the upper side of the clamping device 3. When the cam ring 6 is rotated (clockwise) to the position of the other stopper, the second stopper 12 abuts against the right edge of the clamping device 3, as shown in the lower left section of the second stopper 12.

[0052] Furthermore, in the exemplary embodiment shown in Figure 3, a load compensator 8 is present in each of the three clamp groups 1 and 2, and the load compensator 8 is controlled via a compensator control element 16 by the control contour 13 of the cam ring 6 (similar to the control of the clamping device 3). The load compensator 8 can reduce the high driving force of the cam ring 6 caused by the additional spring force acting on each clamp 1 and 2. This allows for more delicate operation. It also prevents sudden movements (especially during large load peaks) that could result in damage to the wafer 10 when operating the holding device.

[0053] The materials used in contact with the wafer 10 should be designed to avoid damaging the wafer 10 (especially scratching it), and therefore, the materials should be softer than the wafer 10. Furthermore, the formation of particles due to abrasion should be avoided. Chemically nickel-plated aluminum is preferred because it has excellent abrasion resistance and conductivity. A corrosion-resistant and abrasion-resistant layer formed by an electrolytic oxide film of aluminum can also be used, but this layer is not conductive. PEEK can also be considered as an alternative. However, the materials used must also ensure that no movement of the wafer 10 relative to the holding device occurs when it is clamped. Furthermore, electrostatic charge should not occur, and therefore, the use of combinations such as aluminum + nickel or conductive ESD (Electrostatic Discharge) variants of PEEK is recommended.

[0054] Figure 4 (where the wafer 10 is also omitted) shows a magnified view from below of a holding device similar to the exemplary embodiment in Figure 3. This magnification makes it easier to visualize the cooperation between the control elements (only the axial control elements 15 are shown here, as only the axial clamp 2 is visible in this cross-section) and the control contour 13 of the cam ring 6.

[0055] One of the clamping devices 3 (shown on the far left) is shown as an example with a support surface 17 (formed on the side opposite to the observer's view), which is restricted axially outward by a stopper edge 18 (shown with a dashed line because it is formed on the side opposite to the observer's view so that the wafer 10 can be placed on the support surface 17 from above). The support surface 17 for the wafer 10 with the stopper edge 18 is formed directly on the end of the clamping device 3 that protrudes into the opening, or by attaching a lip (not shown) below each support piece 3.

[0056] A key difference from Figure 3 is the presence of a cam ring drive 20 (the axis of the cam ring drive 20 is shown, which is fixedly positioned on a manipulator 9 into which the holding device according to the present invention is inserted), and the cam ring drive 20 rotates the cam ring 6 relative to the base 4 via a control lever 19 formed on the cam ring 6, by a drive lever 26 (which can move around its axis in a circle extending in the plane of the figure (shown by a dashed line) (the direction of movement is indicated by an arrow)).

[0057] Another difference is that the control lever 19 has a fork shape at its free end, so that there is a recess between its tips that can be engaged while the drive lever 26 is moving along the circular orbit indicated by the two arrows. The cam ring 6 rotates as long as the drive lever 26 is engaged with the recess of the control lever 19. In Figure 4, the control lever 19 collides with the second stopper 12, and its right tip faces the inductive proximity sensor 5 in Figure 4. The cam ring drive 20 is switched off when the control lever 19 (coming from the left) passes this position, and the proximity sensor 5 checks at the second stopper 12 whether the locking function by the control lever 19 is being performed correctly. At this point, the drive lever 26 is not engaged with the recess between the tips of the control lever 19. At this position, the axial clamp 2 is in their clamping position A2 (see Figure 8d). In contrast, when the control lever 19 is positioned on its first stopper 11, and the first stopper 11 is located on the opposite side of another inductive proximity sensor 5, the axial clamp 2 is in its open position R1 (see Figure 8a).

[0058] Figure 5 also shows a perspective view of a magnified portion of the holding device when it is incorporated into the manipulator 9 in a modified configuration in which the X-ray tube 21 (not shown) is positioned above the wafer 10 (see also Figures 9a-9c; different representation from Figures 6, 7a, 7b, 8a-8d). Unlike Figure 4, the wafer 10 is inserted here, and the receiving opening 29 is mostly covered (similar to Figures 1, 1a and 1b). The wafer 10 is already centered radially by the radial clamp 1 (shown here, with a projection 7 that fits into a notch in the wafer 10) and is correctly aligned angularly. The device is shown in its open position. The clamping element 32 of the clamping body 30 can be seen in a radially retracted position (see also Figure 9a) for inserting the wafer 10.

[0059] Three combined bearing stopper elements 27a, 27b are positioned on the cam ring 6, thereby (together with further bearing stopper elements 27a, 27b not shown) enabling the cam ring 6 to rotate on the base 4 with low friction. The illustrated bearing stopper elements 27a, 27b consist of a first bearing stopper element 27a that functions as an axial bearing and a second bearing stopper element 27b that functions as a radial bearing. In total, there are six such bearing stopper elements (3+3). In addition to bearings, these bearing stopper elements also function as manual stoppers 11, 12 as shown in Figure 3. The first bearing stopper element 27a corresponds to the second stopper 12, and the second bearing stopper element 27b corresponds to the first stopper 11. If the need for the lowest possible friction (and thereby improved operability) is not a priority, the cam ring 6 may also be held within clamps 1, 2 by sliding bearings or sliding blocks (neither of which are shown) in a simplified version.

[0060] The main difference from the previous drawings is the design of the clamping device 3. These clamping devices 3 are V-shaped rather than U-shaped, and the region where the two legs of the V intersect is not interrupted as in the case of the U-shaped clamping device 3 shown in Figures 3 and 4. The support surface 17 (covered by the wafer 10) is formed in the connection region of the two legs of the V, and the clamps 1 and 2 (which are also attached by springs to flex when pressure is applied to the wafer 10, thereby preventing or mitigating damage to the wafer 10 (this is especially true if the X-ray tube 21 accidentally comes into contact with the wafer 10 and attempts to move it axially, in which case the wafer 10 can avoid the axial pressure of the X-ray tube 21)) protrude through an opening formed between the two legs of the V. The axial clamp 2 is located in an intermediate position between them, as shown in Figure 8b.

[0061] Figure 6 is a schematic longitudinal section of the holding device with most components omitted, where the X-ray tube 21 is located in its edge region below the clamped wafer 10. The central beam 22 of the X-ray tube 21 is indicated at 0°. Due to its spatial extent, the X-ray tube also extends below the support surface 17. Alternatively, instead of the integrated support surface 17, this can also be provided by an additional lip attached to the lower surface of the clamping device 3. In the embodiments described above (particularly in Figures 3 and 4), the lip is an inherent component of the clamping device 3 and is shown in each drawing, for example, by a dashed line (similar to the stopper edge 18). In addition to the support surface 17, a stopper edge 18 is also formed on the inherent lip, which forms a radial circle and whose diameter is slightly larger than the diameter of the wafer 10 being inspected, so that the wafer 10 can be inserted with a little play into the receiving portion formed by the support surface 17 and the stopper edge 18. Since the axial clamp 2 is in its clamping position A2 as shown in Figure 8d, the wafer 10 is fixed to the holding device and cannot be unintentionally moved even during the movement of the manipulator 9 during inspection. It is clearly understood that because the installation height below the surface of the wafer 10 is very low, the X-ray tube 21 with a focal point can be moved very close to the wafer 10, thereby obtaining a very good magnification.

[0062] Figure 7a shows a magnified view of the right-hand portion of Figure 6, and Figure 7b shows a magnified view of the area marked in Figure 7a. In addition to the 0° central beam 22, a 60° central beam 23 is also shown, which strikes the detector 24 and reaches it during X-ray laminography. While the wafer 10 is being inspected at this angle (e.g., 60°), the X-rays striking the detector 24 must not penetrate any material other than the material of the wafer 10 being inspected in order to avoid interference. For this purpose, the clamps 3 and axial clamp 2 (the same applies to the radial clamp 1, not shown) are shaped so as not to be located within the beam cone that strikes the detector 24. For this purpose, the clamps 3 taper at a very flat angle toward the wafer 10, and the axial clamp 2 is positioned very low above the wafer 10. Therefore, the beam region above the holding device is unavailable is indicated by a dashed line. Furthermore, in order to achieve the maximum possible magnification, the X-ray tube 21 must be moved as far upward as possible (towards the wafer 10), so the clamping device 3 must not extend significantly downward in the axial direction from the surface of the wafer 10. Areas where the holding device cannot be used are indicated by dashed lines (Strich-Doppelpunktierung). Therefore, for the holding device including the base 4, clamping device 3 and clamp 2, and cam ring 6, only a substantially wedge-shaped area in the longitudinal section is usable, which is indicated by a single dashed line (Strich-Punktierung). The apex of this angle is theoretically the point where the central beam 22 of the X-ray tube 21 at 0° in the longitudinal section intersects the plane passing through the horizontal end face of the X-ray tube 21; however, due to tolerances, this plane is parallel to and slightly above the described plane. The lower leg extends within the described plane, and the upper leg extends directly below the lower boundary beam of the X-ray tube. This wedge is rotated 360° around the central axis of the receiving opening 29. However, the region around the tip of the wedge (i.e., the apex region) is not accessible by the holding device for practical reasons, as the wafer 10 needs to be inserted and clamped therein (see Figure 7b).

[0063] The axial clamp 2 presses the edges of the wafer 10 that do not have structures to be inspected at its free end. The wafer 10 has an unused edge region for manufacturing reasons (typically, the outer 3 mm of the wafer 10 does not have structures to be inspected (so-called edge exclusion)), and in this region, the axial clamp 2 presses the wafer 10. The free end of the axial clamp 2 is made of resin, preferably conductive PEEK (to avoid electrostatic charge).

[0064] As already explained in Figure 3, the material used in contact with the wafer 10 must be softer than the wafer 10 in order to avoid damaging the wafer 10 (especially scratching it). Furthermore, the formation of particles due to abrasion should be avoided. However, the material must also ensure that the wafer 10 does not move relative to the holding device when clamped. It should also be prevented from becoming electrostatically charged. Moreover, the material must be hard enough to clamp precisely with the specified clamping force, so as not to flow as in the case of an elastomer. Furthermore, the material must have permanent resistance to X-rays to ensure long-term use.

[0065] The four sections of Figure 8 show the four-step process of clamping the wafer 10 on the holding device, with the first fully open state shown in Figure 8a existing after its radial position and angle alignment have been fixed by the radial clamp 1. In all four sections, the region shown in Figure 7a is always shown.

[0066] In Figure 8a, the axial clamp 2 is shown in its open position R1. In this open position R1, the free end of the axial clamp 2 is retracted radially, allowing the wafer 10 to be inserted into the holding device with greater play. This play is illustrated by two vertical dotted lines, the distance between which defines the free gap 25.

[0067] Next, the axial clamp 2 moves from the position shown in Figure 8a to the position shown in Figure 8b by a mechanism actuated by the axial control element 15. The axial clamp 2 moves primarily radially, thereby maintaining the vertical distance A1 from the wafer 10. The (slight) movement of the cam ring 6 precisely determines the angle alignment of the wafer 10. Subsequently, a radial distance R2 from the center of the wafer 10 is achieved, which is closer to the center than it would have been in the open position R1 in Figure 8a. The radial distance R2 is set so that the edge of the wafer 10 is positioned vertically below the free end of the axial clamp 2. The fact that the vertical distance A1 does not change means that even a wafer 10 that is distorted and whose edge is not in the (horizontal) plane can be clamped.

[0068] Subsequently, the axial clamp 2 moves from the position shown in Figure 8b to the position shown in Figure 8c by a mechanism actuated by the axial control element 15. The axial clamp 2 is moved primarily vertically, thereby reducing the vertical distance A1 from the wafer 10. At the intermediate position shown, the free end of the axial clamp 2 is located very close to the top edge of the wafer 10.

[0069] To move from the intermediate position shown in Figure 8c to the clamping position A2 shown in Figure 8d, the free end of the axial clamp 2 is moved downward by a spring. Subsequently, the free end of the axial clamp 2 elastically presses against the edge of the wafer 10, thereby compensating for the potential strain of the wafer 10.

[0070] In summary, the holding device according to the present invention enables easy loading of the wafer 10 to be inspected and secure holding of the wafer 10 during subsequent inspection. In this case, the holding device is positioned very low in the area where the X-ray tube 21 needs to be moved close to the wafer 10, and furthermore, because of the pointed design of the clamping device 3, radial clamp 1 and axial clamp 2, there are no interferences in the beam path when the detector 24 is positioned at a large angle such as 60°, so a very large magnification can be achieved during the X-ray laminography process. Moreover, the wafer 10 is contacted by the radial clamp 1 and axial clamp 2 only in its unused edge region (for example, if edge exclusion exists, the edge region is not occupied by the structure being inspected), and is placed on the support surface 17 only in its unused edge region, so that the entire area of ​​the wafer 10 to be tested can be inspected. Because the height of the support surface 17 and the area around the clamping device 3 is sufficiently low, the X-ray tube 21 can move its focal point very close to the wafer 10, resulting in a very high magnification. The distorted wafer 10 can also be fixedly clamped within the holding device.

[0071] The three sections of Figure 9 illustrate the three-stage process of clamping the wafer 10 in the holding device. Figures 9a and 9b show the state of the radial clamp 1 at the lowest height and the state of the axial clamp 2 at the height above it. The two illustrated planes are simply positioned vertically for clarity; in reality, the two clamps 1 and 2 are in the same plane, differing only in their position on the edge of the wafer 10. In Figure 9c, the radial clamp 1 is not shown because, considering that the wafer 10 is clamped by the axial clamp 2, its state and position are no longer important. Unlike the exemplary embodiment shown in Figure 8, the X-ray tube 21 is positioned above the wafer 10 here.

[0072] Figure 9a shows the open state after the wafer 10 has been placed on the support surface 17 of the axial clamp 2 by an insertion device (e.g., a robotic arm) or an operator. Another difference from the exemplary embodiment shown in Figure 8 is that the axial clamp 2 has two movable parts, a support element 31 and a clamp element 32, and the movement of each of them is controlled by a separate axial control element 15 (not shown).

[0073] In Figure 9a, the X-ray tube 21 is retracted upward to allow the wafer 10 to be inserted. The support element 31 is located below it and is supported by the axial clamp 2 so as to be rotatable around the horizontal rotation axis 33. The clamp element 32 is in a radially retracted position. The same applies to the radial clamp 1, which is also in a radially retracted position. That is, the radial positioning surface 34 of the radial clamp 1 and the inner tip of the clamp element 32 are at the same radial distance from the center of the receiving opening 29 formed by the support surface 17, which is shown, for example, in Figure 3 for another exemplary embodiment (shown by the vertical dashed line on the right, while the vertical dashed line on the left indicates the edge of the wafer 10). This also provides an even larger radial gap during the insertion of the wafer 10, which corresponds to twice the distance between the two vertical dashed lines.

[0074] In Figure 9b, the X-ray tube is in the retracted position as in Figure 9a, and the position of the support element 31 remains unchanged compared to Figure 9a. However, the clamp element 32 has moved radially inward. The same applies to the radial clamp 1. The radial clamp 1 moves inward to a radial position where its radial positioning surface 34 collides with the edge of the wafer 10, and works in cooperation with two other radial clamps 1 (corresponding to those shown in Figures 1, 2, and 3 of other exemplary embodiments) to perform precise positioning (centering and angle alignment) of the wafer 10 on the holding device. The radial position of the radial clamp 1 (on the radial positioning surface 34) from the center of the receiving opening 29 is the same as the radial position of the tip of the clamp element 32 of the axial clamp 2.

[0075] To move from the state in Figure 9b to the state in Figure 9c, the support element 31 is moved upward in the axial direction together with the wafer 10, which is positioned by the axial clamp 1. This movement is performed around the rotation axis 33 until the edge of the wafer 10 is clamped between the support element 31 and the clamp element 33, which does not change position. In this clamped state, the wafer 10 can no longer move from its position, so the radial clamp 1, which is necessary for centering, can be retracted again to avoid damaging the wafer 10. The X-ray tube 21 is moved downward to get as close as possible to the wafer 10 in order to maximize the magnification during inspection. The support element 31 clamps against the spring, thereby preventing excessive pressure on the wafer 10, and allowing the wafer 10 to bend axially downward against the spring pressure if the X-ray tube 21 accidentally makes contact in the axial direction. This also has the advantage that the wafer will not be damaged or destroyed if the X-ray tube accidentally makes contact, as it will bend axially. All of these functions to prevent damage or destruction of the wafer 10. [Explanation of symbols]

[0076] 1 Radial clamp 2. Axial clamping 3 Clamping tool 4 Base 5. Proximity Sensor 6 cam rings 7. Protrusion 8 Load compensator 9 Manipulators 10 wafers 11 First Stopper 12 Second Stopper 13 Control contour 14 Radial control element 15 Axial control elements 16 Compensator control elements 17 Support surface 18 Stopper edge 19 Control Lever 20 Camring Drive 21 X-ray tube 22 Center beam (0°) 23. Center beam (60°) 24 detectors 25 Free spacing 26 Drive lever 27a First bearing stopper element (axial direction) 27b Second bearing stopper element (radial direction) 28 Camring bearing 29 Receiving opening 30 clamping bodies 31 Support elements 32 clamping elements 33 Rotation axis 34 Radial positioning surface A1 Vertical spacing A2 Clamping position R1 Open position R2 Radial distance

Claims

1. A holding device for a disc-shaped member, particularly a wafer (10), wherein the holding device is part of a manipulator (9) of an X-ray inspection system equipped with an X-ray tube (21) and a detector (24), In the holding device, the position and orientation of the member can be corrected by radial clamps (1), and each of the radial clamps (1) exerts a force in the direction of the center of the member within the plane of the member. The holding device allows access to the X-ray tube from one side of the member, and the holding device ensures free space for the beam cone of the X-ray tube on the other side of the member.

2. A holding device for a disc-shaped member, particularly a wafer (10), wherein the holding device is part of a manipulator (9) of an X-ray inspection system, and the holding device is It is equipped with a support surface (17) formed in a plane, The system comprises a base (4) on which the support surface (17) is located, and a cam ring (6) that is rotatable relative to the base (4). It comprises at least three radial clamps (1), each of which is linearly movable between an open position and a locked position by a first displacement device, and each of which is linearly movable radially relative to the support surface (17) by a radial control element (14), It comprises at least two axial clamps (2), each of which is movable between an open position (R1) and a clamped position (A2) by a second displacement device, and each of which is movable radially and axially relative to the support surface (17) by an axial control element (15), The holding device is equipped with a connection mechanism for connecting it to the manipulator (9), The cam ring (6) has a control contour (13) that defines the movement of the radial control element (14) and the axial control element (15), and the radial clamp (1) and the axial clamp (2) are fixedly connected to the base (4), in a holding device.

3. A holding device having the features of claims 1 and 2.

4. The holding device according to claim 2 or 3, wherein the support surface (17) extends at least partially along an annule having a stopper edge (18) that extends at least partially along the outer surface of the cylinder, the stopper edge extends perpendicular to the support surface (17) and has a diameter slightly larger than the diameter of the wafer (10) that the stopper edge will receive, and the base body (4) extends outward from the outer surface of the cylinder.

5. The holding device according to any one of claims 2 to 4, wherein the support surface (17) is formed from individual surfaces formed within the region of the U-shaped connecting bar on the U-shaped clamping device (3), and the free end of the U-shaped parallel bar is fixedly connected to the base (4).

6. The holding device according to any one of claims 2 to 4, wherein the axial clamp (2) each has a support element (31) on which the support surface (17) is formed, and each has a clamp element (32) that is movable independently of each other, the clamp element (32) is movable in the radial direction, and the support element (31) is movable in a direction having an axial component, in particular around a horizontal rotation axis (33).

7. The holding device according to claim 6, wherein the axial control element (14) of the axial clamp (2) cooperates with the support element (31), and the second displacement device further has an additional axial control element (14) that cooperates with the clamp element (32).

8. The holding device according to any one of claims 5 to 7, wherein the radial clamp (1) and / or the axial clamp (2) are positioned within the free region between the two parallel U-shaped bars of the clamping device (3).

9. The holding device according to any one of claims 2 to 8, wherein there are exactly three radial clamps (1), and a projection (7) having the shape of a part of the cylindrical outer surface perpendicular to the support surface is provided at the free end of exactly one of the radial clamps (1).

10. The holding device according to any one of claims 2 to 9, wherein all free ends of the radial clamp (1) and / or the axial clamp (2) are provided with plastic ends that are detachably connected to the remaining portions of the clamps (1, 2), respectively.

11. The holding device according to any one of claims 2 to 10, wherein there are exactly six axial clamps (2) associated in pairs, with equal spacing between adjacent pairs, and / or a radial clamp (1) is positioned between two axial clamps (2) of a pair.

12. The holding device according to any one of claims 2 to 11, wherein the control contour (13) for each radial clamp (1) is the same, and the control contour (13) for each axial clamp (2) is the same.

13. The holding device according to any one of claims 2 to 12, wherein the second displacement device of the axial clamp (2) is each embodied as a slider-crank mechanism or a control link.

14. The holding device according to any one of claims 2 to 13, wherein each of the axial clamps (2) is pressed to a clamping position (A2) by a replaceable spring, and / or each of the radial clamps (1) is pressed to a locked position by a replaceable spring.

15. The holding device according to any one of claims 2 to 14, wherein at least one load compensator (8) is disposed on the base (4), the load compensator (8) has a compensator control element (16), the compensator control element (16) is always in contact with the control contour (13) of the cam ring (6), and the control contour (13) in the vicinity of the compensator control element (16) is formed in the opposite shape to the control contour (13) in the region of the radial control element (14) and the axial control element (15) with respect to the radial distance from the stopper edge (18) of the support surface (17).

16. A holding device according to any one of claims 2 to 15, wherein a first stopper (11) and a second stopper (12) are formed so as to be fixed on the base (4), and a control lever (19) is formed so as to be fixed on the cam ring (6), and the control lever (19) is movable between the first stopper (11) and the second stopper (12).

17. The holding device according to any one of claims 2 to 16, wherein a cam ring drive (20) attached to the manipulator is partially engaged with a control lever (19) of the cam ring (6) via a drive lever (26) in order to rotate the cam ring (6) relative to the base (4), and in particular to move the cam ring (6) between the two stoppers (11, 12).

18. The holding device according to any one of claims 2 to 17, wherein the combination of the clamping device (3) and the base (4) is designed so that there is no portion located outside an angular range exceeding 20° radially with respect to the member around the vertex, the angular range extending from the lower plane of the clamping device (3) which is parallel to the plane of the member, and the vertex is located at the point where the central beam of the X-ray tube (21) used for inspection intersects the plane at the outermost radial point of the X-ray tube (21) during inspection.

19. A method for holding a disc-shaped member, particularly a wafer (10), in a holding device that is part of a manipulator (9) of an X-ray inspection system, The member is placed on the support surface (17) in a pre-aligned manner, Subsequently, radial alignment and angle alignment of the member are performed using a radial clamp (1). A method for fixing the aforementioned member in the axial direction using an axial clamp (2).

20. The method according to claim 19, wherein the movement of the axial clamp (2) is first performed radially and then axially.

21. The method according to claim 19 or 20, wherein first, the clamping element (32) of the axial clamp (2) is moved radially, and then the support element (31) is moved with an axial component, in particular by rotation around the rotation axis (33), until the member is fixed axially between the clamping element (32) and the support element (31).

22. The method according to claim 20 or 21, wherein the radial movement of the axial clamp (2) is performed simultaneously with the radial alignment of the member.

23. The method according to any one of claims 19 to 22, wherein the axial clamp (2) and / or the radial clamp (1) limit the maximum force acting on the wafer (10) by a spring force.

24. The method according to any one of claims 19 to 23, carried out by a holding device according to any one of claims 1 to 18.

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