Fixing device for disc-shaped component for X-ray inspection and method for clamping component

Abstract

The invention relates to a holding device for a disc-shaped component, in particular a wafer 10, which is part of a manipulator 9 of an X-ray inspection system comprising an X-ray tube 21 and a detector 24, in which the position and orientation of the component can be corrected by means of a radial clamp 1, each radial clip exerts a force in the plane of the component in the central direction of the component, and wherein on one side of the component the X-ray tube can be accessed and on the other side of the component a free space is left for the beam cone of the X-ray tube. The invention further relates to a method for clamping a disc-shaped component, in particular a wafer 10, on a holding device as part of an X-ray inspection system manipulator 9, in which the component is placed in a pre-aligned manner on a bearing surface 17, and then the component is radially and angularly aligned by means of a radial clamp 1, the component is fixed in the axial direction through the axial clamp 2.

Description

Technical Field

[0001] This invention relates to a holding device for disc-shaped components, particularly wafers, as part of a manipulator in an X-ray inspection system. The invention also relates to a method for clamping a component at its edge region onto the holding device. For simplicity, the term "wafer" is generally used below to refer to all possible disc-shaped components, but should not be construed as limiting; however, the term "component," particularly in the patent claims, is used to clearly indicate from its content that the patent covers all disc-shaped components. Background Technology

[0002] When examining a wafer with a test object mounted on it using high-resolution computed tomography (CT) with an X-ray inspection system, the X-ray tube must be moved very close to the wafer to achieve the highest magnification of the test object. Due to the spatial extent of the X-ray tube, the corresponding area (above or below the wafer) must be accessible, even extending beyond the side edges of the wafer. Furthermore, the X-ray beam must be able to penetrate the wafer unobstructed so that the image of the test object is not obscured by interference from the wafer support. This means that no material other than the wafer should obstruct the X-ray beam between the detector and the X-ray tube (along the X-ray beam). Additionally, the wafer must be moved along a corresponding trajectory through the X-ray beam by a holding device fixed to it for inspection. There must be no gap between this holding device and the wafer to prevent relative movement that could alter the trajectory. The holding device is part of the manipulator and is typically movable in the X and Y directions within the manipulator plane.

[0003] Most wafer holding devices neglect the requirements of X-ray and computed tomography (CT) techniques. Common solutions either employ a large-area vacuum technique from the bottom, which inevitably means the vacuum beneath the wafer must also be irradiated. The contrast is extremely high compared to the structures on the wafer being inspected, thus obscuring defects or structures in the test object. Alternatively, there are annular supports, where the ring is quite wide, and its depth severely limits magnification due to the required distance between the X-ray tube and the wafer. Furthermore, there are wafer holding devices where the holder is clamped on the outer diameter. In most cases, when the detector is tilted up to 60°, the mechanism or jaws themselves obstruct the illumination of the wafer (e.g., such holding devices are described in CN114603527B and CN117542790A). If the holding device is mounted on the side furthest from the tube, the CT angle results in shadows, reducing the available inspection area to the center of the wafer. Summary of the Invention

[0004] Therefore, the object of the present invention is to provide a holding device for a disc-shaped component, which allows for the inspection of its edge region when the component is inspected in an X-ray inspection system without interference from clamping the component, and also provides a method for clamping the component in its edge region.

[0005] Accordingly, this objective is achieved by a wafer holding device that is part of the manipulator of an X-ray inspection system, including an X-ray tube and a detector, wherein the position and orientation of the component can be corrected by radial clamps, each clamp applying force in the direction of the center of the component plane, and the component can be close to the X-ray tube on one side of the component, while leaving free space for the beam cone of the X-ray tube on the other side of the component.

[0006] This objective is also achieved by a wafer holding device, which is part of the X-ray inspection system manipulator, having a support surface formed in a plane extending at least partially along an annulus, and a stop edge extending at least partially along a cylindrical side surface, perpendicular to the support surface, with a diameter slightly larger than that of the wafer to be received. Thus, the wafer can be easily attached to the holding device by placing it on the support surface. The holding device also has a base extending beyond the cylindrical side surface, on which the support surface rests. This ensures sufficient space on the support surface when placing the wafer. The holding device has at least three radial clamps, each movable linearly in the radial direction relative to the support surface between an open position and a locked position via a first moving device and a radial control block, respectively. This allows the wafer to be positioned very precisely in the holding device, which is necessary for good reconstruction in X-ray tomography. The holding device also has at least two axial clamps, each movable between an open position and a clamped position via a second moving device, each movable via an axial control block, wherein the movement of the axial clamps relative to the support surface is radial and axial. This allows for highly precise positioning of the wafer on the holding device, and minimizes the relative motion of the wafer with respect to the holding device when the manipulator moves. Both X-ray inspection and 3D X-ray methods offer advantages. These include the ability to examine edge regions, high magnification, and large-angle oblique radiography. The latter makes it possible to distinguish different layers of the object being examined. The holding device according to the invention ensures very good reconstruction within the framework of X-ray tomography methods. The support surface, radial clamp, and axial clamp are fixedly connected to the substrate, ensuring a fixed position of the wafer on the holding device. The holding device also has a cam ring with a control profile that is always in contact with the radial and axial control blocks. This makes movement of the radial and axial clamps easy and highly precise. The holding device also has a connecting device for connecting the holding device to the manipulator.

[0007] A preferred embodiment of the invention specifies that the support surface extends at least partially along the annulus, the stop edge extends at least partially along the cylindrical side surface, the stop edge extends perpendicular to the support surface and has a diameter slightly larger than the diameter of the wafer to be received, and the substrate extends beyond the cylindrical side surface. This allows the wafer to be easily inserted into the holding device and pre-centered, and the substrate and support surface are not located in the beam path during X-ray inspection.

[0008] In a preferred embodiment of the invention, the support surface is formed by a single surface on a U-shaped clamp within the U-shaped connecting beam region, and the free ends of the U-shaped parallel beams are fixedly connected to the substrate. This saves a significant amount of material compared to forming the entire support surface, while achieving complete and adequate fixation of the wafer on the holding device, preventing displacement relative to the holding device that could degrade test results as the wafer moves along the trajectory during testing. The U-shaped clamp saves even more material compared to a solid clamp. Alternatively, a V-shaped clamp can be used, wherein the support surface is formed in the region where the two rods of the V-shape intersect, and the free ends of the two rods of the V-shape are fixedly connected to the substrate.

[0009] A preferred embodiment of the invention provides that each axial clamp has a support element with a support surface formed thereon, and each axial clamp has a clamping element that is movable independently of each other. The clamping element is radially movable, and the support element is movable in a direction having an axial component, particularly about a horizontal axis of rotation. This makes insertion easier, especially in designs where the X-ray tube is positioned above the holding device, and therefore the space for inserting the wafer into the holding device is small, as the support surface can be lowered during insertion and then moved only upwards afterwards. A further advantage is that even warped wafers will not accumulate too far in the direction of the X-ray tube, as they are located deeper within the holding device, and the highest point of the wafer's edge facing the tube is restrained by the axial clamps, as these clamps (if spring-loaded) will yield towards the side away from the tube with their springs.

[0010] Another advantageous development of the invention is that the axial control block of the axial clamp cooperates with the support element, and the second moving device also has another axial control block that cooperates with the clamping element. This means that instead of installing a complex mechanism in the second moving device to jointly control the movement of the two separate components, the movement of each of the two separate components (the support element and the clamping element) is controlled separately by the axial control blocks, thus allowing a simple mechanism to be used for each component.

[0011] Another advantageous improvement of the invention is that the radial and / or axial clamps are arranged in the free region of the clamp between the two parallel beams of the U-shape. This makes the device more spatially compact, and because the clamps are arranged between the legs of the clamp, the clamps are also better protected against mechanical damage.

[0012] Another advantageous improvement of the invention is the presence of exactly three radial clamps, one of which has a lug at its free end, the lug having a shape representing a portion of a cylindrical side surface perpendicular to the support surface. By using exactly three radial clamps, the wafer can be precisely positioned on the holding device, and during subsequent wafer inspection, the trajectory can be matched to the holding device without over-positioning. The lug of one radial clamp, designed with a rounded free end, allows for precise angular alignment relative to the wafer's central axis when the lug is inserted into a notch on the wafer's edge (which the wafer typically has).

[0013] Another advantageous improvement of the invention is that all free ends of the radial and / or axial clamps have plastic ends that are detachably connected to the remainder of the respective clamps. By using plastic, particularly a sufficiently soft plastic, it is ensured that the wafer is not damaged when positioned and secured to the retaining device. Since the ends can be removed from the rest of the clamps, if the (preferably soft) plastic ends wear, they can be easily replaced without having to replace the entire affected clamp. Soft non-ferrous metals, rubber, silicone, or silicone rubber can also be used as alternatives to plastic.

[0014] Another advantageous improvement of the invention is the presence of exactly six axial clamps arranged in pairs, with equidistant distances between adjacent pairs and / or radial clamps positioned between the two axial clamps of a pair. The equidistant pairs ensure good support of the wafer on the support surface. If multiple pairs are equidistant from each other, a star-shaped arrangement of fixing points at 120° radially can be achieved by arranging radial clamps between the two axial clamps of a pair, thereby ensuring reliable positioning of the wafer in its plane. This makes it easier to clamp warped wafers on the holding device (meaning the wafer does not extend entirely within a plane). The spatial proximity of the axial clamps to the radial clamps arranged between them ensures that saddle-shaped or Pink-shaped warped wafers can be clamped by the radial clamps using their side surfaces.

[0015] Another advantageous improvement of the invention is that the control profiles of each radial clamp are identical, and the control profiles of each axial clamp are also identical. This ensures synchronous movement of the corresponding clamp types. Alternatively, the clamps can be controlled asynchronously without any adaptation to their design. For example, for radial clamps of different designs, if one of them has a lug that can be inserted into a notch on a wafer, making the wafer more precisely positioned on the holding device, the radial clamp equipped with the lug can be pulled directly out of the notch before axial clamping is performed using the axial clamp. This reduces material wear on the lug.

[0016] Another advantageous improvement of the invention is that the second moving mechanism of the axial clamp is each designed as a slider-crank gearbox or a control linkage. This allows the axial clamp to move radially in a first portion moving from its open position and axially in a second portion moving towards its clamping position, which initially provides more space for inserting the wafer into the holding device and ultimately ensures that the wafer is firmly clamped onto the holding device without any risk of damaging the wafer.

[0017] Another advantageous improvement of the invention is that each axial clamp is pressed into its clamping position by a replaceable spring and / or each radial clamp is pressed into its locking position by a replaceable spring. This allows the contact pressure of the axial clamp in its clamping position or the contact pressure of the radial clamp in its locking position to vary depending on the type of wafer being tested, and the springs can be easily replaced if they wear out. Furthermore, this prevents warped wafers and wafers with non-perfect circularity (i.e., those with diameter and roundness tolerances) from being subjected to excessive force from the clamps, thus damaging the wafer, or to insufficient force, causing the wafer to fail to hold onto the clamps during inspection, resulting in image errors. Another advantage of the spring-loaded axial clamps is that in the event of accidental contact, the wafer can be deflected axially through the X-ray tube without being damaged or destroyed.

[0018] Another advantageous improvement of the invention is that at least one load compensator is disposed on the substrate, the load compensator having a compensator control block that is always in contact with the control profile of the cam ring, wherein the control profile in the region of the compensator control block is designed opposite to the control profiles in the regions of the radial and axial control blocks relative to their radial distance from the stop edge of the support surface. This reduces the high spring load on the axial and radial clamps, which is due to the increased spring force applied to each clamp. This prevents abrupt movements during operation, especially during high load peaks, thereby preventing wafer damage. It also makes the operation more sensitive.

[0019] Another advantageous improvement of the invention is that the first and second stops are fixedly formed on the base, and the control lever is fixedly formed on the cam ring, wherein the control lever is movable between the first and second stops. Thus, when the cam ring is rotated manually or by a motor to clamp or release the wafer, the end position of the cam ring can be easily located. On the one hand, the stops ensure that the cam ring can be easily operated and released; on the other hand, it allows for a simple and intuitive visual indication of whether the clamps are in their respective limit positions (open and locked positions of the radial clamps and open and clamped positions of the axial clamps) and are properly locked.

[0020] Another advantageous improvement of the invention is that the first and second stops are three-dimensional devices. They are particularly preferred for manual movement because they are very simple and inexpensive. When the cam ring is driven by a motor, it is advantageous to perform an additional check to see if the cam ring is actually in one of its stopped positions, thereby checking whether the clamp is in the correct position to hold the wafer, or in a position where the wafer can be easily removed from or inserted into the holding device. For this purpose, inductive near-field sensors are provided, arranged in a way that allows them to detect whether the cam ring is in one of its stopped positions.

[0021] Another advantageous improvement of the invention is that the cam ring driver attached to the manipulator can be connected to a control rod on the cam ring via a drive rod to rotate the cam ring relative to the base, and in particular to move the cam ring between two stops. This means that the operator does not need to enter the beam chamber (where the X-ray inspection system is located according to beam protection regulations), and therefore clamping can be completed more quickly. Furthermore, the holding device according to the invention is also suitable for fully automated loading systems that require unattended continuous operation.

[0022] Another advantageous improvement of the invention is that the combination of the fixture and the substrate is designed such that no part lies outside an angular range of more than 20° relative to the component in the radial direction, the angular range extending from a plane of the bottom surface of the fixture around a vertex parallel to the plane of the component, the vertex being located at the intersection of the central beam of the X-ray tube used for testing at its radially outermost position and the plane. This means that in the X-ray tomography method, the entire wafer (except for the edge areas clamped on the holding device) can be examined, even at tomography angles up to 60° and X-ray beam opening angles of 20°, without interfering with any part of the beam cone. If a larger tomography angle is to be used during testing, the angular range of the fixture and substrate combination must be smaller; for example, when the tomography angle is 65° and the X-ray beam opening angle is 20°, the angular range must be 15°. For smaller tomographic scanning angles, a larger angle range can be used as an alternative design. The angle range must be 90° - tomographic scanning angle - half of the X-ray beam opening angle. For example, if the tomographic scanning angle is 55° and the X-ray beam opening angle is 20°, then the angle range is 25°; if the tomographic scanning angle is 50° and the X-ray beam opening angle is 20°, then the angle range is 30°, and so on.

[0023] By employing the method according to the invention for clamping a disc-shaped component, particularly a wafer, onto a holding device that is part of the manipulator of an X-ray inspection system, the component is placed on a support surface in a pre-aligned manner, then radially and angularly aligned using radial clamps, and fixed axially using axial clamps. Thus, even if the holding device moves during the X-ray inspection of the wafer, the wafer remains precisely aligned and held in its position on the holding device, ensuring no inaccuracies occur during the inspection process. This allows the wafer to be precisely aligned on the holding device and firmly clamped onto it even if the holding device moves during testing, thereby preventing inaccurate data acquisition.

[0024] Another advantageous improvement of the invention is that the movement of the axial clamp occurs first in the radial direction and then in the axial direction. This allows the axial clamp to be in the radially retracted position when the wafer insertion holding device is in place, thereby creating more clearance during insertion.

[0025] Another advantageous improvement of the invention is that the clamping element is first moved radially, and then the support element of the axial clamp is moved axially, particularly about the axis of rotation, until the components are fixed in the axial direction between the clamping element and the support element. This allows for more available space in the axial direction when inserting the wafer into the holding device, which is particularly important for designs that arrange the X-ray tube above the wafer. When the wafer is fixed between the support element and the clamping element, the wafer moves upward so that the X-ray tube can be very close to the wafer, thereby achieving the largest possible magnification.

[0026] Another advantageous improvement of the invention is that the radial movement of the axial clamp occurs simultaneously with the radial alignment of the components. Because the axial clamp moves during wafer positioning, the total time required for wafer insertion, positioning, and clamping is reduced.

[0027] Another advantageous improvement of the invention is that, in the axial and / or radial clamps, the maximum force acting on the wafer is limited by a spring force. The spring force limitation of the axial clamp prevents excessive axial pressure on the wafer edges during clamping, which could damage the wafer. The spring pressure must be large enough to securely hold the wafer in place on the retaining device, and sufficiently limited to prevent edge warping. This is particularly necessary for warped wafers whose shape deviates from an ideal planar shape within a plane. The same applies to the spring force limitation of the radial clamp and its axial pressure on the wafer edges.

[0028] This method is preferably performed by the holding device according to the invention. Attached Figure Description

[0029] Further details and advantages of the invention will now be explained in more detail using exemplary embodiments shown in the accompanying drawings.

[0030] In the attached image:

[0031] Figure 1 An isometric view of the retaining device according to the invention is shown;

[0032] Figure 1a , Figure 1b It shows Figure 1 Two magnified detail images viewed from slightly different angles;

[0033] Figure 2 It shows Figure 1 A schematic top view of the retaining device;

[0034] Figure 3 It shows the relationship with Figure 2 A similar view, but viewed from below, showing in detail the manually movable cam ring and the radial and axial clamps that interact with it;

[0035] Figure 4 It shows Figure 3 Enlarged detail view of the electric implementation method;

[0036] Figure 5 An isometric view showing magnified details in a set of radial and axial clamping regions of another embodiment is shown, wherein an X-ray tube is arranged above a wafer;

[0037] Figure 6 A schematic longitudinal cross-sectional view of the substrate, along with the wafer, X-ray tube, and axial clamp is shown.

[0038] Figure 7a It shows Figure 6 Reduced detail, with an additional inspector;

[0039] Figure 7b It shows Figure 6 A magnified view of a region;

[0040] Figures 8a to 8d A schematic diagram of the four stages of operation of the axial clamp is shown;

[0041] Figures 9a to 9c A schematic diagram of a three-stage operation of radial and axial clamps in an X-ray inspection system is shown, with the X-ray tube positioned above the wafer. Detailed Implementation

[0042] Figure 1 A holding device for an X-ray inspection system according to the invention for inspecting a wafer 10 is shown. This holding device can be mounted to a table-like manipulator 9 (not shown; see also) movable in the XY plane (horizontal). Figure 5 In the process of inspection, the vertical rotation axis of the manipulator 9 is oriented such that it is collinear with the central axis of the wafer 10 to be inspected. Therefore, the holding device according to the invention is collinearly mounted or integrated onto the kinematically final object axis (along the direction of the position-fixing structure). Other components of the system (e.g., X-ray tube 21 (see...)) Figure 6 -8) and the detector (see Figure 7) are not shown because they are not part of this invention.

[0043] The holding device has a base 4 that can rotate relative to the manipulator 9. Nine U-shaped clamps 3 extend into an open internal space, which serves as a receiving opening 29 for the wafer 10 to be inspected (see also). Figure 1a and Figure 1b In the area of ​​the U-shaped connecting beam, the supporting (partial) surface 17 (see...) Figure 3 , 4 (and 6-8) are formed thereon. The supporting (partial) surface 17 is limited by a vertically extending stop edge 18 (see also) Figure 1a and 1bThe free ends of the two parallel beams of the clamp 3 are fixedly connected to the base 4. The wafer 10 clamped in the holding device rests on the support surface 17, which is formed by a portion of the surface on the clamp 3.

[0044] The wafer 10 is centered in the XY plane (horizontal plane) and then clamped by three radial clamps 1 and fixed to the clamps 3 of the holding device by six axial clamps 2. The radial clamps 1 are respectively positioned between two axial clamps 2, with the axial clamps and radial clamps 1 equidistant. The radial clamps 1 are arranged such that they form 120° angles with respect to the center of the wafer 10 (see...). Figure 2 The six axial clamps 2 have the same structure, but... Figure 1 The radial clamp 1 shown differs from the other two radial clamps 1 because it has a lug 7 (for details on lug 7, please refer to...). Figure 1b and Figure 2 (Example). For Figure 1 The three clips 1 and 2 shown below can also be seen from the rear (below the base 4) to view their respective mechanical structures. Figure 1 Between the lower left-side axial clamp 2 and radial clamp 1 mechanisms, a load compensator 8 can also be seen (for more details on this, please see...). Figure 3 (Description).

[0045] The cam ring 6 is also provided with two mechanical stops: a first stop 11 and a second stop 12, which are used to ensure that the cam ring 6, which is rotatably mounted on the base 4 and controls the movement of the radial clamp 1 and the axial clamp 2, can be manually moved between the two stop positions.

[0046] Figure 1a This shows a flatter perspective. Figure 1 Zoomed-in details of the left-hand area.

[0047] On the left, you can see the axial clamp 2, which is located between the two legs of the clamp 3. The front end of the axial clamp 2 is designed as a clamping body 30, which presses the wafer 10 down onto the support surface 17 and clamps it in that position.

[0048] The radial clamp 1 is located to its upper right, between the two legs of the clamp 3. The free end of the radial clamp 1 has a radial positioning surface 34, which presses against the edge of the wafer 10 in the radial direction and, together with the other two radial clamps 1, correctly positions the wafer 10 (see...). Figure 1 The vertically (axially) extending stop edge 18 is clearly visible on the fixture 3, forming a small gap between the stop edge and the edge of the wafer 10. This gap allows the pre-positioned wafer 10 (in the case of automatic feeding) to be placed onto the support surface 17 through the gap, and then finally finely positioned by the three radial clamps 1. The same applies when the wafer 10 is placed on the support surface 17 manually.

[0049] Figure 1b This shows a flatter perspective. Figure 1 Zoomed-in details in the upper right area.

[0050] Axial clamp 2 (right) and radial clamp 1 (top) are also shown here. Axial clamp 2 and... Figure 1a The axial clamps are identical, so they will not be discussed in detail here. However, the radial clamp 1 and... Figure 1a The clip and Figure 1 The other radial clamp 1 shown in the lower middle is different from the other two clamps. It does not have a radial positioning surface 34, but has a lug 7 that extends into a notch at the edge of the wafer 10, thereby ensuring better radial positioning of the wafer 10.

[0051] Both the radial positioning surface 34 and the lug 7 have a height (along the axial direction), which is approximately 6 mm in the exemplary embodiment. This also allows for the secure positioning of a warped wafer 10, where the edge of the wafer 10 is not in the (horizontal) plane.

[0052] exist Figure 2 The retaining device is schematically shown in a top view, wherein the cam ring 6 extends below the radial clamp 1 and the axial clamp 2 together with the corresponding retainer. The rotational movement of the cam ring 6 relative to the base 4 is indicated by double arrows.

[0053] It can also be seen that radial clamp 1 has two different types. Two identical radial clamp 1 are located at Figure 2 Below. On the other hand, the free end of the upper radial clamp 1 has a lug 7 that protrudes further than the free ends of the other two radial clamps 1. The lug 7 extends into the recess of the wafer 10, thereby fixing the precise angular position of the wafer 10 in the holding device, and then in the manipulator 9.

[0054] Because the six axial clamps 2 hold the wafer 10 in the vertical direction (i.e., perpendicular to the axis) Figure 2 The wafer (in the drawing plane) is fixedly secured to the retaining device, thus preventing any (unintentional) positional change relative to the manipulator 9 (in any spatial direction). Excellent fixation is achieved even for warped wafers 10 that are not entirely in a single plane, thanks to the use of six axial clamps 2.

[0055] exist Figure 3For ease of viewing, wafer 10 is omitted and replaced by receiving opening 29. The device is shown from below, clearly showing the design schematic of cam ring 6 and its position relative to the base 4 and clamps 3 (including radial clamp 1 and axial clamp 2). Cam ring 6 has a control profile 13 that interacts with control blocks 14 and 15 assigned to clamps 1 and 2. In an exemplary embodiment, control blocks 14 and 15 are designed as rollers; this reduces friction and the force required to rotate cam ring 6. Radial clamp 1 has radial control blocks 14, and axial clamp 2 has axial control blocks 15. As long as the device is open, i.e., wafer 10 is not clamped in the holding device, control blocks 14 and 15 are always in contact with the control profile 13 of cam ring 6, which can be achieved, for example, by springs (not shown). If the device is closed, i.e., wafer 10 is clamped, control blocks 14 and 15 can also be spaced apart from the control profile 13. Depending on the position of cam ring 6, control blocks 14 and 15 are in different radial positions. The radial change in the position of the axial control block 15 is converted into radial and axial movement of the corresponding axial clamp 2 by a mechanism assigned to the corresponding axial clamp 2. The following is in conjunction with... Figures 8a-8d To explain these movements in more detail.

[0056] When passing through each radial position, the mechanisms assigned to clamps 1 and 2 respectively begin to move.

[0057] The mechanism of radial clamp 1 only needs to cause radial movement of radial clamp 1 in the horizontal plane, so that the wafer 10 in the clamped state abuts its edge against the corresponding free end of radial clamp 1 (e.g., Figure 3 Above and Figure 2 (As shown below). For example, this can be accomplished using a simple lever mechanism. The radial clamp 1 is spring-loaded, which compensates for tolerances at the edge of wafer 10 and limits the maximum force it applies to wafer 10. For Figure 3 Below and Figure 2 The radial clamp 1 shown above, before the axial clamp 2 performs final axial fixation, has its lug 7 moved into the recess of the wafer 10, thus clearly achieving angular alignment of the wafer 10 (the radial advance movement of the radial clamp 1, especially the radial clamp with lug 7, corrects the position and angular alignment of the wafer 10), and then it is pulled out of the recess a short distance again. The radial clamp 1 moves from its open position (where it is as far away as possible from the center of the wafer 10 to be inspected) to its locked position (as described above). Therefore, by employing the holding device according to the invention, positioning accuracy can be improved compared to the accuracy of insertion instruments or manual insertion.

[0058] However, the mechanism of the axial clamp 2 is more complex because when closed (i.e., clamped), the axial clamp 2 must first perform radial movement, followed by vertical movement, to contact the edge of the wafer 10. For this purpose, a slider-crank transmission or connecting rod transmission, known in principle in the prior art, is used. Radial movement is performed from the beginning because this increases the free space when inserting the wafer 10 into the holding device and reduces the risk of collision with the radial clamp 1, thus avoiding damage to the wafer. The various stages of the movement of the axial clamp 2 are shown in Figure 8, which will be described in more detail below.

[0059] Three cam ring bearings 28 are formed on the cam ring 6, which extend radially and are arranged equidistantly from each other, and guide rollers are arranged on them to hold the cam ring 6 in a rolling bearing manner. Alternatively, sliders can be provided on the clamps 1 and 2, and the cam ring 6 can be guided on the sliders.

[0060] Two stops 11 and 12 can be seen on the cam ring 6 at the lower right. The first stop 11 abuts against the clamp 3 shown above. If the cam ring 6 rotates to its other stop position (clockwise), it abuts against the right edge of the clamp 3 shown next to the second stop 12 at the lower left.

[0061] In addition, Figure 3 In this embodiment, for each set of three clamps 1, 2, there is a load compensator 8, which is controlled by the control profile 13 of the cam ring 6 via the compensator control block 16 (similar to the control of the clamp 3). The load compensator 8 can reduce the high driving force of the cam ring 6, which is caused by the increased spring force applied to each clamp 1, 2. This makes the operation more sensitive. When operating the holding device, this also avoids abrupt movements that could damage the wafer 10, especially during high load peaks.

[0062] Materials in contact with wafer 10 must be handled with care to avoid damaging wafer 10 (especially scratching it), therefore they should be softer than wafer 10. Furthermore, particles generated due to abrasion should be avoided. Electroless nickel-plated aluminum is preferred because it is abrasion-resistant and conductive. A corrosion-resistant and abrasion-resistant layer produced by electrolytic oxidation of aluminum can also be used; however, this layer is not conductive. Alternatively, PEEK can be used. However, the materials used must also ensure that wafer 10 does not move relative to the holding device when clamped. Electrostatic charging should also be avoided, therefore a combination of aluminum and nickel or PEEK, a conductive ESD (electrostatic discharge) variant, should be used.

[0063] Figure 4 (Wafer 10 is also omitted in this figure) It is shown from below with Figure 3An enlarged portion of a similar retaining device as in the embodiment. With the magnification, the interaction between the control block (only the axial control block 15 is shown here, as only the axial clamp 2 is visible in detail) and the control profile 13 of the cam ring 6 is more readily apparent.

[0064] On one of the jigs 3 (shown on the far left), a support surface 17 (formed on the side facing away from the observer) is shown as an example, which is restricted outward in the axial direction by a stop edge 18 (shown in dashed lines because it is formed on the side facing away from the observer so that the wafer 10 can be placed from above on the support surface 17 defined by it). The support surface 17 of the wafer 10 with the stop edge 18 is either formed directly at the end of the jig 3 that extends into the opening, or a lip (not shown) is attached below each jig 3.

[0065] and Figure 3 A notable difference is that the figure shows a cam ring driver 20 (showing its shaft, which is fixedly mounted on the actuator 9, into which the retaining device according to the invention is inserted), which causes the cam ring 6 to rotate relative to the base 4 via a control lever 19 formed on the cam ring 6 by a drive rod 26 that can move about the shaft in a circle (shown in dashed lines) extending in the plane of the drawing (the direction of movement is indicated by arrows).

[0066] Another difference is that the free end of control lever 19 is forked, creating a recess between the fork teeth. Drive lever 26 engages with this recess as it moves along the circular paths indicated by the two arrows. As long as drive lever 26 engages with the recess on control lever 19, cam ring 6 rotates. Control lever 19 abuts against... Figure 4 The second stop 12 in the middle, and its right fork and Figure 4 The inductive near-field sensor 5 is opposite. When the control lever 19 passes this position from the left, the cam ring drive 20 will be closed; at this point, the near-field sensor 5 checks whether the control lever 19 has correctly performed the locking function at the second stop 12. Then, the drive lever 26 no longer engages with the recess between the forks on the control lever 19. In this position, the axial clamp 2 is in its clamping position A2 (see Figure 8d On the other hand, when the control lever 19 is at its first stop 11, the axial clamp 2 is in its open position R1 (see...). Figure 8a The stop is opposite to another inductive near-field sensor 5.

[0067] Figure 5 Also shown in isometric view is a magnified detail of a portion of the state-holding device mounted in the manipulator 9, in which, in this variant, the X-ray tube 21 (not shown) is arranged above the wafer 10 (see also...) Figures 9a to 9c ,and Figure 6 , 7a(The illustrations in 7b and 8a to 8d are opposite). Figure 4 Instead, chip 10 is inserted here, and the receiving opening 29 is mainly covered (with...). Figure 1 , 1a Compared to 1b). The wafer has also been radially centered by the radial clamp 1 (the lug 7 of the radial clamp shown in the figure extends into the notch of the wafer 10), and its angular position is correctly aligned. The device is shown in the open position. It can be seen that the clamping element 32 of the clamping body 30 for inserting the wafer 10 is in its radially retracted position (see also). Figure 9a ).

[0068] Three combined bearing stop elements 27a, 27b are shown disposed on the cam ring 6, which (along with other such bearing stop elements 27a, 27b not shown) allow the cam ring 6 to rotate with low friction on the base 4. The bearing stop elements 27a, 27b shown are a first bearing stop element 27a used as an axial bearing and two second bearing stop elements 27b used as radial bearings. There are a total of six such bearing stop elements 27a, 27b (3 plus 3). In addition to support, the bearing stop elements also serve... Figure 3 The function of the manual stop elements 11 and 12. The first bearing stop element 27a corresponds to the second stop element 12, and the second bearing stop element 27b corresponds to the first stop element 11. If minimizing friction (and thus improving operation) is not a priority, the cam ring 6 can also be held in the clamps 1 and 2 in a simplified form by means of a sliding bearing or a slider (neither shown).

[0069] The main difference from the previous diagram lies in the design of fixture 3. These are not U-shaped, but V-shaped; moreover, the area where the two legs of the V-shape meet is uninterrupted, just like... Figure 3 and 4 The same applies to the U-shaped clamp 3 shown. The support surface 17 (covered by the wafer 10) is formed in the connection area of ​​the two V-shaped legs and is also spring-loaded to release when pressure is applied to the wafer 10, thus preventing or limiting damage to the wafer 10 (this is particularly applicable to the axial clamp 2, where the wafer 10 can avoid the axial pressure of the X-ray tube 21 if the X-ray tube 21 accidentally contacts the wafer 10 and attempts to move the wafer axially). Clamps 1 and 2 extend through the opening formed between the two V-shaped legs. The axial clamp 2 is located... Figure 8b The middle position shown.

[0070] Figure 6A schematic longitudinal cross-sectional view of the holding device is shown, with most components omitted, wherein the X-ray tube 21 is located in the edge region below the held wafer 10. The center beam 22 of the X-ray tube 21 at 0° is shown. Due to its spatial extent, the X-ray tube also extends below the support surface 17. Instead of an integrated support surface 17, this can also be achieved by an additional lip attached to the underside of the clamp 3; in previous embodiments (especially...) Figure 3 and Figure 4 In the embodiment shown, the lip is an inherent component of the clamp 3, as illustrated in the figure by the dashed lines (corresponding to the stop edge 18) on the clamp 3. In addition to the support surface 17, a stop edge 18 is formed on the inherent lip, which forms a circle in the radial direction with a diameter slightly larger than the diameter of the wafer 10 to be tested, allowing the wafer to be tested to be inserted into the receiving portion formed by the support surface 17 and the stop edge 18 with a very small gap. The axial clamp 2 is positioned... Figure 8d The clamping position A2 shown secures the wafer 10 to the holding device, preventing accidental movement even when the manipulator 9 moves during testing. It can be clearly seen that, due to the very low mounting height below the plane of the wafer 10, the focal point of the X-ray tube 21 can be moved very close to the wafer 10, resulting in excellent magnification.

[0071] exist Figure 7a In the middle, a magnified view is shown Figure 6 The right side, in Figure 7b In the middle, it is shown again in a magnified manner. Figure 7aThe area marked in the middle. Besides the central beam 22 at 0°, a central beam 23 at 60° is also shown, which reaches the detector 24 and approaches during X-ray tomography. When examining the wafer 10 at, for example, an angle of 60°, the X-ray beam against the detector 24 must not penetrate material other than the wafer 10 to avoid interference. For this purpose, the clamp 3 and the axial clamp 2 (and similarly the radial clamp 1, not shown) are designed so that they are not located within the beam cone against the detector 24. For this purpose, the clamp 3 tapers towards the wafer 10 at a very flat angle, and the axial clamp 2 is positioned very low above the wafer 10. Therefore, the area where the beam cannot be used for holding the device is shown in dashed lines. Furthermore, the clamp 3 cannot extend too far downwards from the plane of the wafer 10 in the axial direction because the X-ray tube 21 must be as high as possible (towards the wafer 10) to achieve the highest possible magnification. This area where the device cannot be used is indicated by dashed lines and double-dot patterns. For the holding device comprising the substrate 4, clamps 3 and clasp 2, and cam ring 6, only a substantially wedge-shaped region exists in the longitudinal section, indicated by a dashed line. Theoretically, the vertex of this angle is the intersection of the 0° center beam of the X-ray tube 21 in the longitudinal section and the plane passing through the horizontal end face of the X-ray tube 21; however, due to tolerances, this plane is slightly parallel above said plane. The lower leg extends in said plane, and the upper leg extends directly below the lower edge ray of the X-ray tube. The wedge is then rotated 360° around the central axis of the receiving opening 29. However, for practical reasons, the area around the tip of the wedge (i.e., the vertex region) is also inaccessible to the holding device, as the wafer 10 must still be inserted and clamped here (see...). Figure 7b ).

[0072] The axial clamp 2 is pressed against the edge of the wafer 10 with its free end, where there is no structure to be tested. For the wafer 10, due to manufacturing reasons, there is an unused edge region; typically, there is no structure to be tested within 3 mm of the outer edge of the wafer 10 (so-called edge exclusion); in this region, the axial clamp 2 is pressed against the wafer 10. The free end of the axial clamp 2 is made of plastic, preferably conductive PEEK (to avoid electrostatic charging).

[0073] like Figure 3 As explained, materials in contact with wafer 10 must be handled with care to avoid damaging wafer 10 (especially scratching it), therefore they should be softer than wafer 10. Furthermore, particles generated due to abrasion should be avoided. However, the material used must also ensure that wafer 10 does not move relative to the holding device when clamped. There should also be no electrostatic charging. The material must also be rigid enough to be clamped with precisely defined forces so that the material does not flow like an elastomer. In addition, the material must be permanently resistant to X-rays to ensure long-term use.

[0074] Figure 8 illustrates the process of clamping the wafer 10 onto the holding device in four stages, divided into four sections, whereby... Figure 8a The fully open first state occurs after the wafer 10 is fixed in a radial position by the radial clamp 1 and relative to its angular direction. Figure 7a The area shown is always displayed in all four sections.

[0075] exist Figure 8a In the middle, the axial clamp 2 is in the open position R1, at which time its free end is in the radially retracted position, so that the wafer 10 can be inserted into the holding device with a larger gap, which is represented by two vertical dashed lines, the distance between which is defined as the free distance 25.

[0076] Then, due to the action of the mechanism controlled by the axial control block 15, the axial clamp 2 moves from... Figure 8a Move to the position shown Figure 8b The position is shown. Here, the axial clamp 2 moves primarily in the radial direction to maintain its vertical distance A1 from the wafer 10. The (slight) movement of the cam ring 6 precisely fixes the angular orientation of the wafer 10. A radial distance R2 from the center of the wafer 10 is then achieved, which is more than... Figure 8a The open position R1 is closer. The radial distance R2 makes the edge of wafer 10 vertically below the free end of the axial clamp 2. The vertical distance A1 remains unchanged, which means that a warped wafer 10 with edges not in a (horizontal) plane can also be clamped.

[0077] Subsequently, the axial clamp 2, under the action of the mechanism operated by the axial control block 15, moves from... Figure 8b Move to the position shown Figure 8c The position shown is such that the axial clamp 2 moves primarily in the vertical direction, thereby reducing its vertical distance A1 from the wafer 10. In the intermediate position shown, the free end of the axial clamp 2 is located immediately adjacent to the edge of the wafer 10.

[0078] In order to move the axial clamp 2 from Figure 8c The middle position shown is moved to Figure 8d In the clamping position A2 shown, the free end of the axial clamp 2 moves downward by a spring. Then, the free end of the axial clamp 2 is pressed against the edge of the wafer 10 by the spring, thereby compensating for any possible deformation of the wafer 10.

[0079] In summary, the holding device according to the present invention can easily load the wafer 10 to be tested and can securely clamp the wafer 10 during testing. In this case, very high magnification can be achieved when performing X-ray tomography, because the holding device is very low in the area where the X-ray tube 21 must be moved close to the wafer 10. Furthermore, due to the pointed design of the clamps 3 and the radial clamps 1 and axial clamps 2, there is no interfering material in the beam path when the detector 24 is arranged at a large angle (e.g., 60°). Moreover, the entire area of ​​the wafer 10 to be tested can be inspected, because the radial clamps 1 and axial clamps 2 only contact its unused edge areas (e.g., edge areas not occupied by the structure to be inspected if edge exclusion exists), and the wafer 10 rests on the support surface 17 only in the unused edge areas. Here, the height of the support surface 17 and the clamp 3 area is very small, allowing the X-ray tube 21 and its focal point to be moved very close to the wafer 10, resulting in very high magnification. Even a warped wafer 10 can be securely clamped in the holding device.

[0080] Figure 9 illustrates the process of clamping the wafer 10 onto the holding device in three stages, divided into three sections. Figure 9a and 9b The diagram shows the state of the lowest radial clamp 1 and the upper axial clamp 2. For clarity, the two planes are arranged vertically; in reality, clamps 1 and 2 are located on the same plane, just at different positions along the edge of wafer 10. Figure 9c In this embodiment, radial clamp 1 is not shown because its condition and position are no longer important, as wafer 10 is clamped here by axial clamp 2. In contrast to the embodiment shown in Figure 8, X-ray tube 21 is arranged above wafer 10 here.

[0081] Figure 9a The diagram shows the open state of the wafer 10 after it 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 embodiment shown in FIG8 is that the axial clamp 2 has two movable parts, namely the support element 31 and the clamping element 32, the movement of which is controlled by separate axial control blocks 15 (not shown).

[0082] exist Figure 9a In the middle, the X-ray tube 21 is retracted upwards so that the wafer 10 can be inserted. The support element 31 is in its lower position and is rotatably mounted on the axial clamp 2 via a horizontal rotation axis 33. The clamping element 32 is in its radially retracted position; the same applies to the axial clamp 1, which is also in its radially retracted position, with its radial positioning surface 34 and the inner tip of the clamping element 32 forming a distance from the support surface 17, and for example in... Figure 3In another embodiment shown, the center of the receiving opening 29 is at the same radial distance (indicated 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 more clearance in the radial direction when the wafer 10 is inserted, equivalent to twice the distance between the two vertical dashed lines.

[0083] exist Figure 9b In the middle, the X-ray tube is still in its retracted position, such as Figure 9a As shown, and the position of the support element 31 is relative to... Figure 9a There is no change compared to the previous version. However, the clamping element 32 has moved inward in the radial direction. The same applies to the radial clamp 1. It has moved so far inward in the radial position that its radial positioning surface 34 abuts against the edge of the wafer 10 and interacts with two other radial clamps 1 (not shown), as in another embodiment. Figure 1 , 2 Compared to the illustration in 3, proper alignment (centering and angular alignment) of the wafer 10 on the holding device is achieved. The radial position of the radial clamp 1 (and its radial positioning surface 34) from the center of the receiving opening 29 is the same as the radial position of the tip of the clamping element 32 of the axial clamp 2.

[0084] In order to Figure 9b The icon in the middle moves to Figure 9c As illustrated, the support element 31, together with the wafer 10 positioned thereon by the axial clamp 1, moves upward in the axial direction. This movement occurs about the rotation axis 33 until the edge of the wafer 10 is clamped between the support element 31 and the clamping element 32, while the position of the clamping element 32 remains unchanged. In this clamped state, the wafer 10 cannot change its position again, allowing the radial clamp 1, necessary for centering the wafer 10, to retract again to avoid damaging the wafer 10. The X-ray tube 21 is lowered as close as possible to the wafer 10 to maximize the magnification during examination. The support element 31 achieves clamping action via a spring, which, on the one hand, prevents excessive pressure on the wafer 10, and on the other hand, allows the wafer 10 to overcome the spring pressure and deflect downward in the axial direction if the X-ray tube 21 accidentally contacts the wafer 10 in the axial direction. Both serve to prevent damage or destruction of the wafer 10.

[0085] List of reference numerals

[0086] 1 Radial clamp

[0087] 2 Axial clamps

[0088] 3. Fixture

[0089] 4. Matrix

[0090] 5. Near-field sensors

[0091] 6 Cam rings

[0092] 7. Protruding ears

[0093] 8. Load compensator

[0094] 9. Manipulator

[0095] 10 chips

[0096] 11 First stop

[0097] 12 Second stop

[0098] 13 Controlling the contour

[0099] 14 Radial control block

[0100] 15 Axial control blocks

[0101] 16 Compensator Control Block

[0102] 17 Support Surface

[0103] 18. Stopping edge

[0104] 19 Control levers

[0105] 20 Cam Ring Driver

[0106] 21 X-ray tubes

[0107] 22 0° center beam

[0108] 23 60° center beam

[0109] 24 detectors

[0110] 25 Free Distance

[0111] 26 drive levers

[0112] 27a First bearing stop element

[0113] 27b Second bearing stop element

[0114] 28 Cam ring bearing

[0115] 29 Receiving opening

[0116] 30 Clamping the main body

[0117] 31 Support element

[0118] 32 Clamping elements

[0119] 33. Axis of rotation

[0120] 34 Radial positioning surface

[0121] A1 Vertical distance

[0122] A2 Clamping Position

[0123] R1 Open Location

[0124] R2 radial distance

Claims

1. A holding device for disc-shaped components, particularly wafers (10), said holding device being part of a manipulator (9) of an X-ray inspection system comprising an X-ray tube (21) and a detector (24), wherein, The position and orientation of the component can be corrected by radial clamps (1), each radial clamp applying force in the plane of the component toward the center of the component, and wherein on one side of the component, the X-ray tube can be brought close to the component, and on the other side of the component, free space is left for the beam cone of the X-ray tube.

2. The holding device according to claim 1, wherein, The retaining device It has a support surface (17) formed in a plane. It has a base (4), the support surface (17) is located on the base (4), and has a cam ring (6) that is rotatable relative to the base. It has at least three radial clamps (1), each of which can be linearly moved in the radial direction relative to the support surface (17) between an open position and a locked position via a first moving device and a radial control block (14). It has at least two axial clamps (2), each axial clamp being movable relative to the support surface (17) in the radial and axial directions respectively between the open position (R1) and the clamped position (A2) via a second moving device and via an axial control block (15). It has a connecting device for connecting the holding device to the manipulator (9), The cam ring (6) has a control profile (13) that defines the movement of the radial control block (14) and the axial control block (15), and the radial clamp (1) and the axial clamp (2) are fixedly connected to the base (4).

3. A holding device for disc-shaped components, particularly wafers (10), said holding device being part of the manipulator (9) of an X-ray inspection system, said holding device It has a support surface (17) formed in a plane. It has a base (4), the support surface (17) is located on the base (4), and has a cam ring (6) that is rotatable relative to the base. It has at least three radial clamps (1), each of which can be linearly moved in the radial direction relative to the support surface (17) between an open position and a locked position via a first moving device and a radial control block (14). It has at least two axial clamps (2), each axial clamp being movable relative to the support surface (17) in the radial and axial directions respectively between the open position (R1) and the clamped position (A2) via a second moving device and via an axial control block (15). It has a connecting device for connecting the holding device to the manipulator (9), in, The cam ring (6) has a control profile (13) that defines the movement of the radial control block (14) and the axial control block (15), and the radial clamp (1) and the axial clamp (2) are fixedly connected to the base (4).

4. The holding device according to claim 2 or 3, wherein, The support surface (17) extends at least partially along the annulus, the stop edge (18) extends at least partially along the cylindrical side surface, the stop edge extends perpendicular to the support surface (17) and its diameter is slightly larger than the diameter of the wafer (10) to be received, and the substrate (4) extends beyond the cylindrical side surface.

5. The holding device according to claim 2 or 3, wherein, The support surface (17) is formed by a single surface formed on a U-shaped clamp (3) in the U-shaped connecting beam region, and the free end of the U-shaped parallel amount is fixedly connected to the base (4).

6. The holding device according to claim 2 or 3, wherein, Each axial clamp (2) has a support element (31) on which a support surface (17) is formed, and each axial clamp has a clamping element (32) that can move independently of each other, wherein the clamping element (32) can move radially, and the support element (31) can move in a direction having an axial component, particularly about a horizontal axis of rotation (33).

7. The holding device according to claim 6, wherein, The axial control block (14) of the axial clamp (2) cooperates with the support element (31), and the second moving device also has another axial control block (14) that cooperates with the clamping element (32).

8. The holding device according to claim 5, wherein, The radial clamp (1) and / or the axial clamp (2) are arranged in the free region of the clamp (3) between the two parallel beams of the U-shape.

9. The holding device according to claim 2 or 3, wherein, There are exactly three radial clamps (1), one of which has a lug (7) at its free end, the lug having the shape of a portion of the cylindrical side surface perpendicular to the support surface.

10. The holding device according to claim 2 or 3, wherein, All free ends of the radial clamp (1) and / or axial clamp (2) have plastic ends that are detachably connected to the remainder of the respective radial clamp (1) and / or axial clamp (2).

11. The holding device according to claim 2 or 3, wherein, There are exactly six axial clamps (2) arranged in pairs, and the distance between adjacent pairs is equal and / or the radial clamps (1) are arranged between the two axial clamps (2) of a pair.

12. The holding device according to claim 2 or 3, wherein, The control profile (13) of each radial clamp (1) is the same, and the control profile (13) of each axial clamp (2) is the same.

13. The holding device according to claim 2 or 3, wherein, The second moving device of each of the axial clamps (2) is designed as a slider-crank gearbox or a control linkage.

14. The holding device according to claim 2 or 3, wherein, Each axial clamp (2) is pressed into its clamping position (A2) by a replaceable spring and / or each radial clamp (1) is pressed into its locking position by a replaceable spring.

15. The holding device according to claim 4, wherein, At least one load compensator (8) is disposed on the base (4), the load compensator having a compensator control block (16) that is always in contact with the control profile (13) of the cam ring (6), wherein the control profile (13) in the region of the compensator control block (16) is designed opposite to the control profile (13) in the regions of the radial control block (14) and the axial control block (15) with respect to its radial distance from the stop edge (18) of the support surface (17).

16. The holding device according to claim 2 or 3, wherein, The first stop (11) and the second stop (12) are fixedly formed on the base (4), and the control lever (19) is fixedly formed on the cam ring (6), wherein the control lever (19) is movable between the first stop (11) and the second stop (12).

17. The holding device according to claim 2 or 3, wherein, The first stop (11) and the second stop (12) are fixedly formed on the base (4), wherein the cam ring driver (20) attached to the actuator is partially engaged with the control rod (19) on the cam ring (6) via the drive rod (26) to rotate the cam ring (6) relative to the base (4) and, in particular, to move the cam ring (6) between the first stop (11) and the second stop (12).

18. The holding device according to claim 2 or 3, wherein, The combination of the fixture (3) and the base (4) is designed such that no part is located outside an angle range of more than 20° relative to the component in the radial direction, the angle range being a plane starting from the bottom surface of the fixture (3) around a vertex that is parallel to the plane of the component, the vertex being located at the intersection of the central beam of the X-ray tube (21) used for inspection during inspection at its radially outermost position with the plane.

19. A method for clamping a disc-shaped component, particularly a wafer (10), onto a holding device that is part of a manipulator (9) of an X-ray inspection system. in, The component is placed on the support surface (17) in a pre-aligned manner. Then, the radial clamp (1) is used to perform radial and angular alignment of the component. The component is fixed in the axial direction by means of axial clamp (2).

20. The method according to claim 19, wherein, The movement of the axial clamp (2) occurs first in the radial direction and then in the axial direction.

21. The method according to claim 19 or 20, wherein, First, the clamping element (32) is moved radially, and then the support element (31) of the axial clamp (2) is moved axially, particularly about the rotation axis (33), until the component is fixed in the axial direction between the clamping element (32) and the support element (31).

22. The method according to claim 20, wherein, The radial movement of the axial clamp (2) occurs simultaneously with the radial alignment of the component.

23. The method according to claim 19 or 20, wherein, In the axial clamp (2) and / or radial clamp (1), the maximum force acting on the wafer (10) is limited by the spring force.

24. The method according to claim 19 or 20, wherein, The method is implemented by a holding device according to any one of claims 1 to 18.

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