KR20210055708A - Method for positioning test substrate, probes and inspection unit relative to each other, and tester for carrying out the method - Google Patents

Abstract

The present invention relates to a method and a tester (1) for positioning a test substrate (5), probes (6) and an inspection unit (9) relative to each other. In the above method, the test substrate 5 and the probes 6 are aligned with each other at an intended relative position at least in the XY-plane, and the inspection unit 9 has the focus of the inspection unit 9 It moves to the Z-position above the relative position set on the observation point of the test board 5. In order to simplify and accelerate the tracking of the inspection unit 9, the test substrate 5 and the inspection unit 9 are moved synchronously in the Z-direction from this starting position, so that the focal plane is maintained. do.

Description

Method for positioning test substrate, probes and inspection unit relative to each other, and tester for carrying out the method

The present invention relates generally to a method for positioning a test substrate, probes and an inspection unit relative to each other, wherein the test substrate and probes are at least XY-plane Aligned with each other at an intended relative position within the inspection unit, the inspection unit moves to a Z-position above the relative position where the focus of the inspection unit is set on the observation point of the test substrate. The invention also relates to a tester for carrying out the method.

It is known that various electronic components, commonly referred to as test boards, are inspected in terms of different properties, or undergo special tests. In this case, the test substrates may exist in different fabrication- and integration steps. In this way, tests of semiconductor chips, hybrid components, micro-mechanical and micro-optical components that are still located in the wafer assembly, separated, or already integrated into rather complex circuits are carried out. do.

To inspect the test substrates, test stations, commonly referred to as testers, are used, the test stations comprising a chuck having a surface for receiving the test substrates. The chuck is a receiving device suitably adjusted for the fixation of the test substrate, the contact of the test substrate and the inspection conditions, and can mostly be moved in the X-, Y- and Z-directions by a moving unit.

Subsequently, the tester includes a plurality of probes, and the probes are fixed by a probe holder. As probes, single probes or probe cards having a plurality of probe tips may be used according to a test substrate and a test situation. The probe holder mainly includes a probe holding plate, wherein the probe holding plate is arranged to be placed on a chuck, and supports single probes or probe cards fixed by probe heads. do. The probe holding plate and/or probe heads may also use moving units, by means of which the probes may move together or one by one in at least the Z-direction.

Subsequently, the tester includes an inspection unit, which is used for image representation of the test substrate and probe tips. The inspection unit includes a microscope and/or a camera, and the camera can look onto the surface of the test substrate in the Z-direction. To approach the test substrate in the Z-direction so that the focus of the inspection unit is set on a specific observation point of the test substrate, that is, such an observation point can be clearly projected, and eg For example, in order to provide a sufficient gap again when the probes need to be replaced, the inspection unit often uses a mobile unit as well.

In order to bring the probe tips or test board or intermediate positions into focus, for example by means of an inspection unit, the moving units primarily allow the movement of the mentioned parts of the tester independently of one another. For motorized movement of the chuck and/or probe holding plate or single probes and/or inspection unit, the moving units are mainly equipped with drive devices. The motorized movement of the mentioned parts is implemented by means of a control unit configured for this.

Focusing of the observation point may be performed several times during the course of the inspection sequence, including repeated contact of one or more points of the test substrate and thus the feed motion in the X-, Y- and Z-directions required for this. It must be repeated. This increases the time required with each new feeding operation.

In order to provide electrical contact, the Z-direction between the probes and the test substrates, with the movability always made within the XY-plane defined as the plane on which the receiving surface of the chuck lies and is mostly implemented by the moving unit of the chuck. The supply operation to is required.

First, the probes and the test substrate are positioned relative to each other in the X-Y-plane by one or more of the moving units so that they are overlaid with each other at intervals. Contact is provided in a subsequent feeding operation in the Z-direction (hereinafter referred to as a Z-feeding operation). This Z-position is referred to as the contact position. After the end of the test, the contact is released by movement in the Z-direction and the next contact position in the X-Y-plane is reached.

The Z-supply operation to the contact position can be accomplished by movement of the probes or by movement of the test substrate. The advantage in the supply of probes is that even the smallest alternative movement of the probe tip observed in the XY-direction can be continuously observed, which is achieved by the mounting of the probe tip and is desirable to provide a more reliable electrical contact. The relative positions of the substrate do not change, and thus the focus on the contact surface is maintained.

In different situations it has proven desirable to reach the intermediate position of the probe tips in the Z-direction on the test substrate. A sufficiently large spacing of the probe tips with respect to the test substrate occurs at such an intermediate position so that the probe tips can be corrected in the X-Y-plane without risk of being damaged, for example. However, this intermediate position allows for quick and manual feeding to the contact position and adjustment of the X-Y-positions at the same time.

It is preferred that the supply in the Z-direction is made by means of a chuck, or in many cases it is only possible by means of the chuck due to the shape of the probe holder. However, in order to identify the contact surfaces of the test board, for example, tracking of the inspection unit must be premised. If intermediate positions are also to be reached, the time required for this is no longer in terms of part- or fully automated inspection and the constant demand for cost-effectiveness due to the intermediate corrections required in the two parts, the chuck and the inspection unit. It becomes an unacceptable level.

Therefore, the need to simplify and accelerate the feeding operation of the inspection unit in the Z-direction is raised.

In this case, the accuracy of the feeding of the inspection unit in the X-Y-plane must also be maintained.

Subsequently, at least the final feed from the intermediate position to the contact position must be possible by manual conditions as well.

The concept for solving the posed problem is that the effect to be achieved when the probe holding plate with probes is raised and lowered and the test substrate and inspection unit are not moved to provide and release contact between the test substrate and the probe tips. It is proposed to simulate by the chuck and inspection unit. This means that the test substrate and the inspection unit are synchronously in the Z-direction from a starting position at which the focus of the inspection unit is set on the observation point of the test substrate, for example, on the contact surface on the surface of the test substrate ( By moving synchronously, an intended end position of the test substrate relative to the probe tips, for example a contact position, is set.

Such a synchronous movement is made in such a way that the focal plane is maintained at least during the Z-feed operation, and in some cases even during the release of the contact, so that the point of view on the test substrate is clearly projected, as is known from the movement of the probes of the prior art. . This movement method may be regarded as a virtual movement of the probe holding plate, and may be applied even when the probe holding plate cannot move or the movement of the probe holding plate acts inappropriately in the inspection sequence.

The "one" movement in the Z-direction is not only the overall sequence of movements that must be carried out to overcome the required distance in the Z-direction, for example the distance until the probe tips on the test substrate come into contact. It also includes individual parts of the movement sequence. This part may be, for example, a supply from the above-mentioned intermediate position or toward an intermediate position toward the test substrate or in a direction away from such a test substrate.

In the following, the features used to implement the concept are described. Those skilled in the art may variously combine these features with each other in different embodiments, as long as those skilled in the art deem it desirable and suitable for the application situation.

Directional markings of X, Y and Z correspond to conventional use in the field of the present application indicating horizontal X- and Y-directions and vertical Z-directions.

Synchronous movement under the maintenance of the focal plane includes not only the length of movement in the Z-direction but also a temporal factor.

“Synchronous” refers herein to the same movement in time as well, and is caused by the control unit when the movement of the focal point is also identified in an automated manner by conventional algorithms and the corresponding compensation movement is initiated, and/or It includes delays that can be implemented by current conventional computer technology.

Studies have shown that the start of the actual movement of the chuck and the start of the movement of the chuck as such, the waiting time, i.e. initiated for example, by the current tester technology, in order to be able to identify the movement of the focal plane in time. For example, it has been found that the delay between the actual movements of the inspection unit is 300 ms.

“Timely” means that an alternative movement initiated, for example by mounting the probe tips on a test substrate, is when the probe tip is still on the contact area, and/or has not yet been damaged at all, or other undesired relative position. It means the fact that it is detected when it reaches. Preferably the waiting time is less than 200 ms, preferably less than 100 ms, more preferably less than 50 ms, more preferably less than 40 ms, more preferably less than 30 ms, more preferably less than 20 ms, more preferably less than 10 ms, More preferably less than 5 ms. As the scale of the performance of electronic components and computer technology increases, the acceptable alternative travel and implementable latency may continue to decrease.

Synchronous movement of the test board and the inspection unit can be implemented by, for example, synchronous control signals for carrying out the movement of the chuck and the inspection unit, in which case the above waiting times are applied also in relation to the time interval of the control signals. I can.

Only when the chuck movement is described below, the movement of the chuck is the same as the movement of the test substrate, because the chuck supports the test substrate on its own horizontal receiving surface.

Corresponding to one design example of the method according to the invention, the movement of the test substrate and the inspection unit in the Z-direction can be initiated by a manipulator body which is part of the manipulator of the used tester. . The manipulator body moves, so to speak, so that the movement is clearly determined by the direction of movement and the amount of movement, for example length or angle. For movement of the chuck and/or inspection unit to be carried out in the Z-direction, the direction of movement is determined from the movement direction of the manipulator body, and the movement length is determined from the movement amount of the manipulator body, so that the movement of the manipulator body is And the amount of movement is detected technically by means of a suitable movement measurement value sensor.

Based on the measured values and the control signals generated from the measured values, the chuck or test unit is moved, and due to the computer-technical combination of the two moving units by the control unit, each of the other tester parts moves this initial movement. It follows miraculously. As long as synchronous movement is allowed, other methods are also considered for connecting the two movements depending on the configuration of the inspection device. The initial movement can be effected, for example, by means of a chuck, and the inspection unit follows the initial movement of the chuck. It is also possible to move both parts in a different order or on the basis of the control signals generated from the measurements.

In order to implement the synchronous movement of the test board and the inspection unit, control signals for controlling the mobile units are generated based on the measured values of the movement value sensor of the manipulator, so that the manipulator controls the driving devices of the two mobile units during electric movement. , The manipulator can be combined with two moving units.

Alternatively, the manipulator may be in direct actuating relationship with only one of the two mobile units. In this design example, the second movement unit performs a compensation movement in the Z-direction.

Corresponding to yet another embodiment, the manipulator body is moved manually. Alternatively, the movement of the manipulator body can be effected by means of a suitable manipulator control device.

The movement of the manipulator body may be rotation of the manipulator body about a rotation axis. In this case, the direction of rotation clockwise or counterclockwise determines the direction in the Z-direction up or down, and the rotation angle is a positive or negative stroke value, i.e. movement in the Z-direction. Determine the length

Corresponding to another design example of the method according to the invention, the movement of the manipulator body can be limited by one or a plurality of stops. The stop portion limits the amount of movement and can be defined by the contact position. Stops can also be defined for the general use of preferred start-, middle- and end positions, such as minimum distance positions.

It has been found that the axes of movement of the chuck and inspection unit in the Z-direction no longer lie exactly parallel to each other. Corresponding to one design example of the method according to the invention, in order to compensate for the change in XY-relative positions between the observation point of the test substrate and the focus of the inspection unit, the deviation according to the Z-movement is determined and itself Compensated by the mobile unit. To this end, the waiting time described above for synchronous movement may also be applied.

Compensation of XY-deviation, referred to herein as linear correction, depends on the direction of movement, and depending on the degree of deviation during or after movement in the Z-direction is carried out, one or more of the two parts in the XY-direction. This can be done by further movement of the part. For example, when the test board moves in the XY-direction, in order to prevent damage to the contact surface due to later compensation, compensation is preferably performed during the Z-movement and before the probe tips are mounted on the test board. .

Alternatively, the compensation can be made after the Z-shift. For this, as long as the inspection unit moves, the relative position between the test substrate and the probe holder is not affected.

The deviations are determined based on the spacing between the two contact partners that are still present during the Z-movement, which is the movement of the image field relative to the test substrate if the Z-movement proceeds not parallel. Cause. These deviations can be identified in the top view. Such deviations in the movement of the image field and in the Z-synchronization movement are in-situ by known methods, for example by pattern recognition methods or by monitoring of the spatial positions of two parts or other suitable measures. Can be confirmed.

Alternatively, the position of the Z-axes can be ascertained, for example from a previous feeding operation or an analysis of the tester. In all cases the linear correction can be made by reverse control movement during or after the Z-travel.

The tester usable for carrying out the method according to the invention comprises a positioning device as well as a chuck, probes with corresponding holders and an inspection unit, which are common parts, the positioning device comprising moving units, at least In order to effect the movement of the chuck and the inspection unit in the Z-direction, it comprises at least one moving unit for the chuck and at least one moving unit for the inspection unit. One or more control units for continuously controlling the two moving units are configured so that the movement of the chuck and the inspection unit can be performed synchronously according to the above description. Alternatively, each of the mobile units may use its own control unit, which control units are connected to each other in a communicative manner to effect synchronous movement.

The synchronous movement is made so that the focal plane is maintained, so that the observation point on the test substrate is projected clearly.

Corresponding to one design example, the positioning device of the tester comprises a manipulator, which manipulator is used for movement of the chuck or inspection unit.

The manipulator includes a manipulator body, an operation element for moving the manipulator body, and a movement value sensor. As the manipulator body, objects that can clearly infer the moving direction and the amount of movement are considered from their own movement.

Corresponding to one design example of the manipulator, a clear direction of movement is ensured if the manipulator has exactly one degree of freedom in its own movement.

Corresponding to yet another design example of the manipulator, the manipulator body may be a rotating body that is rotatably arranged about its own axis of rotation.

The manipulation of the manipulator is performed by a suitable manipulation element, which is suitably adjusted for a manual or mechanical manipulation of the manipulator body and, for example, a rotational or movable movement.

The direction of movement and the amount of movement are determined by a movement value sensor of the manipulator, which is configured accordingly for this purpose. Depending on the type of the movement value sensor and according to the movement to be determined by the movement value sensor, the movement value sensor is disposed relative to the manipulator body. In the example of the rotating body, a movement value sensor is a rotation value sensor that determines a rotation direction and a rotation angle, and is disposed, for example, in an axial direction with respect to the rotating body. To determine the required measurements, alternatively more than one travel value sensor may be used. These measurements are, if necessary, pre-processed and transmitted to one or more control units.

Control signals are generated based on the measured values, which are used to control the movement of the chuck or inspection unit or both parts in the Z-direction according to the above description. For this purpose, the movement value sensor is connected in a communicative manner with the control unit.

Corresponding to another design example of the tester, the manipulator includes one or more stops for limiting the movement of the manipulator body. It is advantageous if such a stop can be set variably and/or for a defined distance in the Z-direction. Because the stop is adjustable, different end- or intermediate positions can be reached accurately, even manually. The one or more stops may be implemented in the manipulator in terms of hardware, or may be implemented in terms of software, for example by means of a control unit.

Corresponding to the description of the method according to the invention, it may be necessary to carry out a linear correction of the relative position of the chuck and inspection unit in the X-Y-direction in order to be able to always use the intended image section. Testers designed for linear calibration for this purpose include one or more moving units approaching the chuck or inspection unit, which are configured to carry out Z-movement as well as movement of the parts in the X- and Y-directions. . Optionally, both parts may be connected to these mobile units. Furthermore, the control unit is also designed in terms of hardware- and software to control the corresponding one or more mobile units in the X-, Y- and Z-directions.

In the following, the present invention is explained in more detail by examples.
Fig. 1 shows a tester with components important for the present invention;
2A and 2B show in detail a perspective view of one embodiment of a manipulator, as shown and in a cut-away state; And
3 shows a manipulator body with an adjustable stop.
The drawings show the device only schematically within the scope necessary to illustrate the invention. The drawings do not require completeness or accuracy to scale.

The tester according to FIG. 1 comprises a chuck 2 with a moving unit 3 of the chuck. The chuck 2 can move in the X-, Y- and Z-directions. The directions are indicated by a coordinate system. On the upper horizontal receiving surface 4, a test substrate 5, for example, a wafer is disposed. The wafer is contacted by probes 6 fixed by probe heads 7. The probe heads are disposed on the probe holding plate 8.

By looking at the inspection unit 9 from above in the Z-direction, for example a camera, onto the test substrate 5, so to speak, onto the contact point, such a contact point can be projected clearly. The inspection unit 9 likewise utilizes a moving unit 10, by means of which the inspection unit 9 moves, for example in the X-, Y- and Z-directions as well, at least in the Z-direction. I can.

The dynamic certainty of the movable parts by the corresponding moving units or holders, the dynamic certainty of the chuck 2 and the inspection unit 9 by the moving units 3, 10 in this figure, and the probe holding plate 8 In order to clearly show the dynamic certainty of the probe heads 7 due to this, such components are shown fixedly and thus statically with respect to the common reference system (hatched horizontal lines).

The two mobile units 3, 10 are connected for operation, by way of example, but not limitation, in a manner communicable with the common control unit 11, which is in terms of hardware and software. It is configured for.

In the drawing, as the chuck 2 moves to the contact position K _C , the probe 6 contacts the test substrate 5. The inspection unit 9 is also located in its own contact position K _I. In this contact position the focus of the inspection unit 9 is set on the surface of the wafer 5 and thus also on the tips of the probes 6 lying on the surface.

When the contact is released, the chuck 2 moves down (shown by the arrow). Synchronously to this, the inspection unit 9 also moves down the same distance (shown by the same arrow path) in the Z-direction. The movement is at each intermediate position (Z _C , Z _I ) (shown by the dashed line of the receiving surface 4 of the chuck 2 and the lower edge of the inspection unit 9, respectively) or each end position ( E _C , E _I ) (shown by the chain lines of the receiving surface 4 of the chuck 2 and the lower edge of the inspection unit 9, respectively). The observation point 12 set on the test substrate 5 due to the synchronous movement of the chuck 2 and the inspection unit 9, in this embodiment, one of the contact surfaces of the wafer that has been contacted or has been contacted by the probe tip. The contact surface of is always clearly identified during movement of the chuck 2 to one of the deeper positions.

In order to reach another electronic component of the wafer and subsequently contact by the probes 6, the chuck 2 at the _{intermediate position Z C} or the end position E _{C is X- and} /Or can move in the Y-direction.

In order to contact the next electronic component, the wafer 5 is raised by means of a chuck 2, for example to an intermediate position Z _C. Such an intermediate position (Z _C), may be consistent with the previous intermediate position (Z _C), and an intermediate position (Z _C) of the respective further electronic components in the wafer 5 from the self-Z- coordinates. Subsequently, the chuck 2 is moved to the contact position K _C.

In the control unit 11, synchronously with respect to the control signals for moving the chuck 2, the test unit first moves to a corresponding intermediate position (Z _I ), and then to a subsequent contact position (K _I ). Control signals for moving the inspection unit 10 are generated.

2A and 2B illustrate, by way of example and not limitation, one embodiment of a manipulator 13, which can be used to move the chuck 2. The same reference numerals used in the two figures each designate the same part of the manipulator.

The manipulator 13 itself is manually operated and controls the electric movement of the chuck 2.

The manipulator 13 includes a manipulator body 20, which is formed as a cylindrical rotating body. The manipulator body 20 is rotatably supported in the housing 21.

The manipulator body 20 is assembled with an operation element 23 implemented as a lever 23 in this embodiment by a suitable connector 22 (see Fig. 2B), such that such an operation element As a result, the manipulator body 20 can be manually rotated clockwise and counterclockwise. This lever 23 can also be used for other movements of alternative embodiments of the manipulator body. The lever 23 is guided within the frame 25 as the contour of the lever corresponds to the contour of the frame 25.

Subsequently, the operating force and operating torque of the manipulator body 20 and the sensitivity of the manipulator body can be changed by the brakes 24 accordingly. In this embodiment, two brakes 24 are arranged, and the brakes press the outer surface of the cylindrical manipulator body 20 with a settable force.

A movement value sensor 26 in the axial direction adjacent to the manipulator body 20, and a rotation value sensor 26 in this embodiment are disposed, and the rotation value sensor measures a rotation direction and a rotation angle. The measurements are optionally transmitted to the control unit 11 (see Fig. 1) via a signal conductor 28 after pre-processing.

The manipulator body 20 and the rotation value sensor 26 are protected from external influences by a casing 27 and can be assembled to the tester (see Fig. 1).

In Figure 3 one embodiment of an alternative manipulator body 30 is shown, in which the manipulator body 30 is formed as a rotary knob 31 and can be locked to prescribed angular positions. have. The rotary knob 31 may rotate around its own shaft 32. On the periphery of the part, in its outer surface 33, three radial recesses 34 are arranged, and a pin 35 can be inserted into the recesses. The pin 35 is provided with one of the recesses 34 through a guide slit 37 of a guide plate 36 disposed concentrically with respect to the rotary knob 31. It is guided into the recess and in this way limits the possible rotational movement of the rotary knob 31 to the length of the guide slit 37. If different recesses 34 are used, different rotational movements can be carried out, thereby changing the length of movement which can be carried out by the moving units 3 and 10.

Alternative embodiments of manipulators or stops are possible. If the tester includes a plurality of manipulators with different functions, tactile differences can be supported through design.

1 tester
2 ships
3 Chuck's moving direction
4 receiving surface
5 test board, wafer
6 probe
7 probe head
8 probe holding plate
9 inspection unit
10 Direction of movement of the inspection unit
11 control unit
12 observation points
13 manipulator
20 manipulator body
21 housing
22 connector
23 Operating element, lever
24 breaks
25 frames
26 Movement value sensor, rotation value sensor
27 casing
28 signal conductor
30 manipulator body
31 rotary knob
32 axes
33 external surface
34 recess
35 pin
36 guide plate
37 guide slit
Contact position of K _{C chuck}
Z _C chuck middle position
E _C end position of chuck
Contact position of the K _{I inspection unit}
Middle position of the Z _{I inspection unit}
E _I End position of inspection unit

Claims (13)

As a method for positioning a test substrate 5, probes 6 and inspection unit 9 relative to each other,
In the above method, the test substrate 5 and the probes 6 are aligned with each other at an intended relative position at least in the XY-plane, and the inspection unit 9 has a focus of the inspection unit 9 on the test substrate. Move to the Z-position above the relative position set on the observation point in (5),
Method, characterized in that the test substrate (5) and the inspection unit (9) move synchronously in the Z-direction from this starting position, thereby maintaining the focal plane. The method of claim 1,
Movement of the test substrate 5 and the inspection unit 9 in the Z-direction is initiated by a manually moving manipulator body 20, 30, and the movement direction of the manipulator body 20, 30 And the amount of movement is detected by measurement technology, from which the direction in the Z-direction and the length of movement in the Z-direction are determined. The method according to claim 1 or 2,
The movement of the test substrate 5 and the inspection unit 9 in the Z-direction is initiated by the manipulator bodies 20 and 30 performing a rotational motion, and the rotation direction and rotation angle of the manipulator bodies 20 and 30 A method, characterized in that the measurement technique is detected, from which the direction in the Z-direction and the length of movement in the Z-direction are determined. The method according to any one of claims 1 to 3,
Method, characterized in that the movement of the manipulator body (20, 30) is limited by one or more optionally variable stops. The method of claim 6,
The method, characterized in that the at least one stop is set for the distance to be overcome. The method according to any one of claims 1 to 5,
Linear correction of the deviations is made at the relative position between the test substrate 5 and the inspection unit 9 in the XY-direction during or after the Z-movement of the test substrate 5 and the inspection unit 9 Characterized by the method. The method according to any one of claims 1 to 6,
Method, characterized in that the maintenance of the focal plane and/or the relative position between the test substrate 5 and the inspection unit 9 in the XY-direction is monitored in-situ and the identified deviations are compensated. As a tester for inspecting test boards,
The tester includes a chuck 2 for receiving and fixing the test board 5, probes 6 for contacting the test board 5, and an observation point of the test board 5 during inspection. And a positioning device for moving the chuck 2 and the inspection unit 9 and an inspection unit 9 for focusing projection,
The positioning device comprises moving units (3, 10), the moving units being configured to effect movement of the chuck (2) and inspection unit (9) at least in the Z-direction, and one or more control units (11), wherein the control unit moves the movable units (3, 10) in the Z-direction so as to maintain the focal plane, the synchronous movement of the chuck (2) and the inspection unit (9). Characterized in that configured to control, tester. The method of claim 8,
The positioning device includes a manipulator 13 having a manipulator body 20, 30, an operation element 23 for moving the manipulator body 20, 30, and a movement value sensor 26, , The movement value sensor 26 is configured to detect the movement method and range of the manipulator bodies 20 and 30 in measurement technology, and is disposed relative to the manipulator bodies 20 and 30, and In order to generate control signals for moving the chuck 2 and/or the inspection unit 9 in the Z-direction as a basis, the manipulator 13 is connected in a communicative manner with the control unit 11. Characterized in that, the tester. The method of claim 9,
Tester, characterized in that the manipulator body (20, 30) has exactly one degree of freedom of movement. The method of claim 9 or 10,
The tester, characterized in that the manipulator body (20, 30) is a rotating body and the movement value sensor (26) is a rotation value sensor. The method according to any one of claims 9 to 11,
The manipulator (13), characterized in that it comprises at least one stop for limiting the movement of the manipulator body (20, 30). The method according to any one of claims 8 to 12,
The tester comprises one or more moving units (3, 10), which are configured to effect movement of the chuck (2) and/or inspection unit (9) in the X-, Y-direction, the The control unit 11 is configured to determine deviations of the set XY-relative position and/or the set Z-relative position between the observation point 12 of the test substrate 5 and the focus of the inspection unit 9 Characterized in that, the tester.

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