DE102020212970A1 - Method for calibrating an optical sensor - Google Patents

Abstract

The invention relates to a method for calibrating a sensor (41) for measuring an absolute position and location of a light beam (30) in a reference coordinate system (38) of a measuring device (40) with the following method steps: Determination of an auxiliary coordinate system (39) of a calibration standard (60 ), - Determination of the position of the touch point (34) of the calibration standard (60) in the auxiliary coordinate system (39), - Fixation of the calibration standard (60) in the measuring device (40), - Determination of the position of the auxiliary coordinate system (39) of the calibration standard (60) in the reference coordinate system (38) of the measuring device (40), - positioning of a sensor (41) in relation to the touch point (34) of the calibration standard (60), - determination of the location and the position of the measuring location (44) of the sensor (41) in Reference coordinate system (38) using the touch point (34).

Description

The invention relates to a method for calibrating an optical sensor, in particular for measuring interferometer beams in space, in particular in a projection exposure system for semiconductor lithography.

Projection exposure systems for semiconductor technology have extremely high demands on the imaging accuracy in order to be able to produce the desired microscopic structures as error-free as possible. The optical components used for imaging for the systems described above must be positioned with the greatest precision in order to be able to guarantee sufficient imaging quality. The functional principle of the above-mentioned systems is based on generating extremely fine structures down to the nanometer range on an element to be structured, which is provided with photosensitive material, by means of a generally scaling-down image of structures on a mask, a so-called reticle. The minimum dimensions of the structures produced depend directly on the wavelength of the light used. Recently, light sources with an emission wavelength in the range of a few nanometers, for example between 1 nm and 30 nm, in particular in the range of 13.5 nm, have been used more and more. The wavelength range described is also referred to as the EUV range. The move to the EUV range means doing without refractive media, which can no longer be used sensibly at this wavelength, and moving to pure mirror systems. As a result, the basic structure of the optical elements and their arrangement in the imaging optics have also changed, making it more difficult to set up a fixed reference, the so-called sensor frame.

One solution to this problem is to use interferometers as sensors for positioning the optical elements. Interferometers have the advantage that the distance between the measuring head and the reference mirror required for the interferometer can be very large, so that the sensor frame can still be designed to be relatively compact and simple. The measuring beam of the interferometer, which is usually designed as a laser beam, must be aligned with the reference mirror in such a way that the reflected beam is reflected back into the measuring head within the measuring range of the sensor, largely independently of the position of the two parts to one another. In systems such as projection exposure systems, for example, this can lead to very complex assembly and adjustment processes, since the optical elements and thus the reference mirrors are not yet mounted when the sensor frame is set up with the measuring heads of the interferometer, or the measuring heads are not accessible in the assembled state. To adjust the measuring beams, a measuring device is required to determine the absolute position and location of the measuring beams in space. A major challenge here is to achieve optimal measurement accuracy of the measuring device and the sensors used in it, such as cameras. In other words, the most accurate possible calibration of the sensors used is desirable.

The object of the present invention is to provide a method which solves the above-described problem of calibrating a sensor as precisely as possible for localizing the course of laser beams in space.

This object is achieved by a method with the features of the independent claim. The subclaims relate to advantageous developments and variants of the invention.

• - Bestimmung eines Hilfskoordinatensystems eines einen optischen Taster umfassenden Kalibriernormals.
• - Bestimmung der Lage des Tastpunktes des optischen Tasters in dem Hilfskoordinatensystem des Kalibriernormals.
• - Fixierung des Kalibriernormals in einem Messgerät.
• - Bestimmung der Lage des Hilfskoordinatensystems des Kalibriernormals im Referenzkoordinatensystem des Messgerätes.
• - Positionierung eines Sensors in Bezug zu dem Tastpunkt des optischen Tasters.
• - Bestimmung des Ortes und der Lage des Messortes des Sensors im Referenzkoordinatensystem mit Hilfe des Tastpunktes.

A method according to the invention for calibrating a sensor for measuring an absolute position and location of a light beam in a reference coordinate system of a measuring device comprises the following method steps:

• - Determination of an auxiliary coordinate system of a calibration standard comprising an optical probe.
• - Determination of the position of the touch point of the optical probe in the auxiliary coordinate system of the calibration standard.
• - Fixation of the calibration standard in a measuring device.
• - Determination of the position of the auxiliary coordinate system of the calibration standard in the reference coordinate system of the measuring device.
• - Positioning of a sensor in relation to the touch point of the optical button.
• - Determination of the location and the position of the measuring location of the sensor in the reference coordinate system with the help of the touch point.

The touch point is a point of light usually generated by a laser and focused by an optical element such as a spherical lens, which thus also corresponds to the focal point of the optical button. The relative position of the touch point to the ball center of the optical probe is defined by the distance z of the focal plane to the ball center of the spherical lens along the central axis of the optical probe and via the connection vector b between the intersection of the central axis with the focal plane and the focal point on the focal plane. The central axis is the Axis that runs through the connection of the optical probe and the center of the sphere of the spherical lens.

In the course of the calibration of the sensor, the touch point is used to determine the location and the position of the measuring location of the sensor in relation to the reference coordinate system, that is to say usually the coordinate system of a coordinate measuring machine.

In addition, the calibration standard can include a probe ball. The probe ball, ie a ball that can be mechanically touched and whose ball diameter is precisely known, can either be identical to the optical element of the optical probe, such as a ball lens, or be designed as an additional ball. If the probe ball is an additionally designed probe ball, the distance from the center point of the probe ball to the probe point must be known.

Furthermore, the calibration standard can include at least three reference points. The reference points can be designed, for example, as the center points of probe balls, in turn one of the at least three probe balls can also be the optical element of the calibration standard, which is embodied as a ball lens. If the stylus spheres are not arranged in a line, a coordinate system can be defined by touching the three stylus spheres, in which the touch point of the optical stylus can be determined. A Cartesian coordinate system is expediently spanned by the position of the probe balls.

The probe balls of the calibration standard essentially fulfill two functions. On the one hand, they can be used in the manufacture of the calibration standard to determine the position of the touch point in the auxiliary coordinate system of the calibration standard. For this purpose, the calibration standard itself is used as a probe in a coordinate measuring machine. The auxiliary coordinate system of the calibration standard can be determined with a calibrated reference sphere of the measuring device. The measuring device can be, for example, a coordinate measuring device. The calibrated reference sphere, whose diameter is known very precisely and whose exact position has been determined in the reference coordinate system, is mounted in the coordinate measuring machine. The optical probe is then mounted on a movable arm of the coordinate measuring machine and the position of the at least three probe balls is determined with the aid of the reference ball. On the basis of the at least three points determined in this way, an auxiliary coordinate system can now be set up which corresponds to the coordinate system of the calibration standard, that is to say the auxiliary coordinate system. Once the auxiliary coordinate system has been determined, the position of the tactile point in the auxiliary coordinate system can now be determined on the basis of the known distance between the touch point of the optical probe in relation to the center point of the spherical lens and the known position of the center point of the spherical lens in the auxiliary coordinate system.

The calibration standard can now be dismantled from the movable arm of the coordinate measuring machine and fixed at a suitable point in the measuring machine. Then the probe balls of the calibration standard can be used to touch the position of the auxiliary coordinate system of the calibration standard in the reference coordinate system of the coordinate measuring machine and thus to determine the position of the touch point in the reference coordinate system. The position of the auxiliary coordinate system of the calibration standard in the reference coordinate system can be determined by touching the probe balls of the calibration standard. For this purpose, the position of the center points of the three probe balls and thus the position of the auxiliary coordinate system in the reference coordinate system are determined with a tactile probe head, which is arranged on the movable arm of the coordinate measuring machine. This means that the position of the touch point in the reference coordinate system is also automatically known.

Alternatively, the calibration standard can be produced as a body that can only be touched by touch, which also generates an optical touch point. In contrast to the variant described above, the calibration standard does not necessarily have to be suitable as a button itself. In this embodiment of the invention, the position of the touch point can be determined by means of a multisensor measuring device. In the context of the present invention, a multisensor measuring device is understood to mean a device by means of which measurements can be carried out both optically and tactilely. An optical and a tactile sensor use the same coordinate system and are calibrated relative to it. A calibration standard designed in this way can also be fixed and touched in the coordinate measuring machine as described above, so that the position of the touch point in the reference coordinate system is known.

As already mentioned, the sensor for determining the position of the laser beam can in particular be designed as a camera. The camera can also be attached to a movable arm of the coordinate measuring machine, the position of the camera or the measuring location of the camera in the reference coordinate system not yet being known. With this configuration, the orientation of a laser beam running in space can be determined by detecting the laser beam at two points in the reference coordinate system. More than two points can also be recorded to determine the laser beam. The absolute position of the laser beam in space can be due to the missing Information about the absolute position of the measurement location of the camera in the room cannot be determined. Alternatively, the sensor can also be designed as a photodiode.

To calibrate the sensor, the touch point can now be mapped onto a light-sensitive electronic component of the camera. The light-sensitive component can be designed as a so-called CCD chip or a so-called CMOS sensor. The camera can also only comprise a light-sensitive electronic component, i.e. no imaging optics, since the laser beam to be measured and the touch point are already strongly focused and the determination of the center is carried out using averaging algorithms, so that the center can also be used for a finitely extended, with regard to its intensity normally distributed spot can be determined. Alternatively, the camera can also include imaging optics. The distance between the object plane of the imaging optics, that is to say the location in which the touch point is arranged in space, from the light-sensitive electronic component is known from the optical design.

In addition, a pixel of the light-sensitive electronic component in the center of the imaged touch point can be determined by computer. The position of the pixel in the reference coordinate system corresponds to the coordinates of the touch point of the optical probe of the calibration standard. In the case of a camera with imaging optics, the distance of the light-sensitive electronic component to the object plane of the imaging optics of the camera and the distance of the pixel located in the center of the imaged touch point to the center of the image field must also be determined. To determine the position of the light-sensitive electronic component, at least three different pixels of the light-sensitive electronic component can be determined. Alternatively, the optical axis of the imaging optics of the camera can be arranged parallel to the connecting line between the center point of the spherical lens and the touch point. As a result, the position of the light-sensitive electronic component and thus the measurement location is now known in the coordinates of the reference coordinate system. The information about the current position of the measurement location is retained in particular even when the sensor is moved with the movable arm of the coordinate measuring device. This means that an absolute position of a laser beam can now be determined.

Furthermore, the calibration standard can be fixed in several positions in the measuring device. This can enable the sensor to be calibrated at different angles, which in the field of coordinate measuring technology can usually be used in the case of swiveling probes and sensors in order to compensate for systematic errors in the axes of rotation of the movable arms of the coordinate measuring machine. Only a few angles are measured and correction values are interpolated for the remaining angles on the basis of the data of the measured angles. As a result, the effort for correcting the systematic errors of the axes of rotation is advantageously reduced to a minimum. If the sensor is only used for a few measurements, the measured angles used to reduce the systematic errors can expediently coincide with the angles used later. Alternatively, the correction values can also be determined in advance and adopted for the measurements with the sensor, whereby at least a large part of the systematic errors can be compensated.

• 1 den prinzipiellen Aufbau einer Projektionsbelichtungsanlage, für deren Vermessung die Erfindung verwirklicht sein kann,
• 2 den prinzipiellen Aufbau einer Projektionsoptik, in der die Erfindung verwirklicht sein kann,
• 3 einen optischen Taster, der bei der Umsetzung der Erfindung Verwendung finden kann,
• 4 in den 4a und 4b zwei Möglichkeiten zur Ermittlung des Hilfskoordinatensystems eines Kalibriernormals,
• 5 eine Möglichkeit zur Bestimmung der Lage des Hilfskoordinatensystems des Kalibriernormals in einem Referenzkoordinatensystem eines Koordinatenmessgerätes,
• 6 eine weitere Detailansicht der Erfindung mit einem als Kamera ausgebildeten und zu kalibrierenden Sensor,
• 7 einen Schnitt durch die abbildende Optik in 6 gezeigten Kamera, und
• 8 ein Flussdiagramm zu einem erfindungsgemäßen Verfahren.

In the following, exemplary embodiments and variants of the invention are explained in more detail with reference to the drawing. Show it

• 1 the basic structure of a projection exposure system for the measurement of which the invention can be implemented,
• 2 the basic structure of a projection optics in which the invention can be implemented,
• 3 an optical button that can be used to implement the invention,
• 4th in the 4a and 4b two options for determining the auxiliary coordinate system of a calibration standard,
• 5 a possibility to determine the position of the auxiliary coordinate system of the calibration standard in a reference coordinate system of a coordinate measuring machine,
• 6th a further detailed view of the invention with a sensor designed as a camera and to be calibrated,
• 7th a section through the imaging optics in 6th shown camera, and
• 8th a flow chart for a method according to the invention.

1 shows an example of the basic structure of an EUV projection exposure system 1 for microlithography in which the invention can find application. A lighting system of the projection exposure machine 1 points next to a light source 3 an illumination optics 4th for illuminating an object field 5 in one object level 6th on. One by the light source 3 generated EUV radiation 14th as useful optical radiation is by means of an in the light source 3 Integrated collector aligned in such a way that it is in the area of an intermediate focus plane 15th passes through an intermediate focus before moving onto a field facet mirror 2 meets. According to the field facet mirror 2 becomes the EUV radiation 14th from a pupil facet mirror 16 reflected. With the help of the pupil facet mirror 16 and an optical assembly 17th with mirrors 18th , 19th and 20th become field facets of the field facet mirror 2 in the object field 5 pictured.

A is illuminated in the object field 5 arranged reticle 7th , that of a reticle holder shown schematically 8th is held. A projection optics shown only schematically 9 serves to map the object field 5 in an image field 10 in an image plane 11 . A structure is imaged on the reticle 7th onto a light-sensitive layer in the area of the image field 10 in the image plane 11 arranged wafers 12th , that of a wafer holder also shown in detail 13th is held. The light source 3 can emit useful radiation in particular in a wavelength range between 5 nm and 120 nm.

The invention can also be used in a DUV system which is not shown. A DUV system is basically like the EUV system described above 1 constructed, whereby mirrors and lenses can be used as optical elements in a DUV system and the light source of a DUV system emits useful radiation in a wavelength range from 100 nm to 300 nm.

2 shows a basic view of the projection optics 9 the projection exposure system 1 in which several as a mirror 21.x formed optical elements are arranged. The mirror 21.x are arranged, for example, via actuators on a support frame (both not shown) and can be moved relative to this. The position and orientation of the mirrors 21.x are via sensors 22.x captured on a sensor frame 23 , the opposite of the environment via decoupling elements 25th is decoupled, arranged. For the sake of clarity, there was only one sensor 22.x per mirror 21.x shown, with the position and orientation of the mirror 21.x in up to 6 straight lines of freedom through sensors 22.x is captured. Due to the spatial arrangement of the mirrors 21.x that is dictated by the optical design and the endeavor to frame the sensor 23 as a reference for the position and location of the sensors 22.x The distance between the sensor frame can be made as stiff as possible and therefore as compact as possible 23 and the respective reference mirror 24.x of the sensors 22.x at the mirror 21.x vary greatly and exceed the working distance of most common sensor types. The sensors 22.x are therefore designed as interferometers, which have the advantage of measuring very precisely even over long distances. As part of the assembly of the projection optics 9 For reasons of accessibility and complexity, it is sometimes not possible to use the measuring heads 49.x of the interferometer, which is on the sensor frame 23 are arranged with the reference mirrors 24.x on the mirrors 21.x to adjust or calibrate. Therefore, the interferometer must be attached to the sensor frame for assembly and adjustment 23 a special procedure can be used.

3 shows a detailed view of the invention in which an optical button 26th which can be used in practicing the invention. The optical button 26th includes a ball lens 27 holding over one arm 28 with a connection 29 for example, can be connected to a coordinate measuring machine. Through the ball lens 27 becomes a laser beam 30th , the optical button 26th usually through a fiber 31 is supplied, in a so-called focal plane 32 focused. The level of focus 32 is at a distance z perpendicular to the central axis 33 the ball lens oriented, with the central axis 33 in extension of the longitudinal axis of the arm 28 and through the center of the ball lens 27 runs. The tactile point 34 is still about a vector b from the intersection of the central axis 33 with the focus plane 32 offset. The optical button 26th is calibrated, so that the distance z and the vector b are known. The optical button 26th can also be used as a tactile sensor, with the ball lens 27 can be used as a tactile probe ball.

4a shows a first possibility for determining the auxiliary coordinate system of a calibration standard 60 , in which an optical button 26th as part of the calibration standard 60 and a reference sphere 37 in a coordinate measuring machine 40 is shown. The reference sphere 37 is fixed to the coordinate measuring machine 40 connected, the position of the reference sphere was previously determined precisely by a button, not shown, so that the position of the reference sphere 37 in the reference coordinate system 38 of the coordinate measuring machine 40 is known. The calibration standard 60 includes besides the ball lens 27 two more probe balls 36.1 , 36.2 that are so on the calibration standard 60 are arranged that they are together with the ball lens 27 which can also be touched mechanically, set up an auxiliary coordinate system. The centers of the spheres do not necessarily have to be as shown in 4th already set up a Cartesian coordinate system, it is sufficient if the three probe balls 36.1 , 36.2 , 27 are not arranged in a line. The centers of the individual probe balls 36.1 , 36.2 , 27 are on the reference sphere 37 measured. An auxiliary coordinate system can be derived from the three centers 39 can be determined and in this auxiliary coordinate system 39 the exact position of the touch point 34 in the auxiliary coordinate system with the known distance z and the vector b and the position of the center point of the spherical lens 27 to be determined.

An alternative calibration standard 60.1 is in 4b shown. In the variant shown in this figure, instead of the additional Stylus balls simple reference surfaces 62 on the calibration standard 60.1 arranged. This can be done using a tactile sensor 61 can be touched by the coordinate measuring device 40, which is only indicated schematically in the figure, and the auxiliary coordinate system of the calibration standard 60.1 to be determined. The position of the touch point 34.1 can be determined in the same coordinate measuring machine. For this purpose, in the example shown in the figure, the coordinate measuring device 40 is a multisensor measuring device with additional optics 63 formed that a determination of the location of the touch point 34.1 allowed. Before this measurement, as with all measurements with such a multisensor measuring device, a tactile-optical comparison of the coordinate measuring device on a purely mechanical reference body has to take place, that is, the relative position of the in the optics 63 contained optical sensor of the coordinate measuring machine 40 to the tactile sensor 61 must be determined beforehand.

5 shows a possibility of determining the position of the auxiliary coordinate system of the calibration standard 60 in which the calibration standard 60 in a coordinate measuring machine 40 is firmly mounted. The position of the auxiliary coordinate system 39 is in the reference coordinate system 38 of the coordinate measuring machine 40 by a button 48 of the coordinate measuring machine 40 certainly. By connecting the reference coordinate system 38 and the auxiliary coordinate system 39 is therefore also the position of the touch point 34 in the reference coordinate system 38 known. The determination of the position of the touch point 34.1 of the in 4b calibration standards shown 60.1 can be done analogously.

6th shows a further detailed view of the invention, in which a camera 41 trained sensor to be calibrated, which is attached to a measuring arm 42 of the coordinate measuring machine 40 is arranged, is shown. The camera 41 is now positioned so that the touch point previously determined by probing 34 of the calibration standard 60 on that in the camera 41 arranged as a CCD chip 43 formed photosensitive electronic component is imaged. This point is also called the measurement location 44 the camera 41 designated. Is the position of this measurement location 44 in the reference coordinate system 38 definitely is the camera 41 calibrated. In other words, it is the position of the measurement site 44 now in every position of the measuring arm 42 known, and the absolute position of a laser beam in space can now be determined. The optical button 26th is on a turntable 57.1 arranged, which in turn on a second turntable 57.2 is arranged, the axes of rotation 58.1 , 58.2 of the two turntables 57.1 , 57.2 are aligned perpendicular to each other, so that the orientation of the calibration standard 60 can be adjusted. This allows the camera 41 in different orientations in the reference coordinate system 38 are calibrated, whereby the errors of the axes of rotation (not shown) of the coordinate measuring machine 40 can advantageously be reduced to a minimum. Calibration of the camera is preferred because it is less complex 41 in only one orientation, in this case the optical button 26th firmly with the coordinate measuring machine 40 can be connected.

7th shows a detailed view of the invention in which a section through the imaging optics 45 the camera 41 with the CCD chip 43 is shown. The tactile point 34 is due to the imaging optics 45 the camera 41 onto the CCD chip 43 pictured. Now the pixel can be in the center of the displayed touch point 34 can be calculated computationally, so that in addition to the location of the CCD chip 43 also the position of the touch point shown 34 on the CCD chip 43 is known and thus the measurement location 44 the camera 41 is known. The optical axis 46 the imaging optics 45 the camera 41 is parallel to the connecting line 47 between midpoint 50 the ball lens 27 and the tactile point 34 aligned, which also means the position, i.e. the orientation of the CCD chip 43 in the reference coordinate system 38 is known. Alternatively, the camera can also be moved so that the touch point 34 of the optical button 26th at three different pixels on the CCD chip 43 is detected and from the position of the three points and the position of the camera 41 in the reference coordinate system 38 the location of the CCD chip 43 in the reference coordinate system 38 is determined. It's a camera too 41 without imaging optics 45 conceivable. This is where the CCD chip 43 positioned so that the tactile point 34 on the CCD chip 43 lies.

• In einem ersten Verfahrensschritt 51 wird ein Hilfskoordinatensystem 39 eines Kalibriernormals 60 bestimmt.
• In einem zweiten Verfahrensschritt 52 wird die Lage des Tastpunktes 34 des Kalibriernormals 60 in dem Hilfskoordinatensystem 39 bestimmt.
• In einem dritten Verfahrensschritt 53 wird der das Kalibriernormal 60 im Messgerät 40 fixiert.
• In einem vierten Verfahrensschritt 54 wird die Lage des Hilfskoordinatensystems 39 des Kalibriernormals 60 im Referenzkoordinatensystem 38 bestimmt.
• In einem fünften Verfahrensschritt 55 wird ein Sensor 41 in Bezug zu dem Tastpunkt 34 des Kalibriernormals 60 positioniert.
• In einem sechsten Verfahrensschritt 56 wird der Ort und die Lage des Messortes 44 des Sensors 41 im Referenzkoordinatensystem 38 mit Hilfe des Tastpunktes 34 bestimmt.

8th shows a possible method for calibrating a sensor for measuring an absolute position and location of a light beam in a reference coordinate system of a measuring device with the following process steps:

• In a first process step 51 becomes an auxiliary coordinate system 39 of a calibration standard 60 certainly.
• In a second process step 52 becomes the position of the touch point 34 of the calibration standard 60 in the auxiliary coordinate system 39 certainly.
• In a third process step 53 becomes the calibration standard 60 in the measuring device 40 fixed.
• In a fourth process step 54 becomes the position of the auxiliary coordinate system 39 of the calibration standard 60 in the reference coordinate system 38 certainly.
• In a fifth process step 55 becomes a sensor 41 in relation to the tactile point 34 of the calibration standard 60 positioned.
• In a sixth process step 56 becomes the location and location of the measurement site 44 of the sensor 41 in the reference coordinate system 38 with the help of the touch point 34 certainly.

List of reference symbols

1

Projection exposure system

2

Field facet mirror

3

Light source

4th

Lighting optics

5

Object field

6th

Object level

7th

Reticle

8th

Reticle holder

9

Projection optics

10

Field of view

11

Image plane

12th

Wafer

13th

Wafer holder

14th

EUV radiation

15th

Interfield focus plane

16

Pupil facet mirror

17th

Optical assembly

18th

mirror

19th

mirror

20th

mirror

21.x

mirror

22.x

Sensors

23

Sensor frame

24.x

Reference mirror interferometer

25th

Decoupling element

26.26.1

optical button

27.27.1

Ball lens

28

poor

29

Connection

30th

laser beam

31

fiber

32

Focus plane

33

Central axis

34,34.1

Tactile point

36.1,36.2

Stylus ball

37

Reference sphere

38

Reference coordinate system

39

Auxiliary coordinate system

40

Coordinate measuring machine

41

camera

42

Measuring arm

43

CCD chip

44

Measurement location

45

imaging optics camera

46

optical axis imaging optics camera

47

Connecting line center point - focus point

48

Button

49.x

Measuring head

50

Center point ball lens

51

Process step 1

52

Step 2

53

Step 3

54

Step 4

55

Step 5

56

Step 6

57.1,57.2

Turntable

58.1, 58.2

Rotary axis turntable

60,60.1

Calibration standard

61

Tactile sensor

62

Reference area

63

optics

Claims (11)

Method for calibrating a sensor (41) for measuring an absolute position and location of a light beam (30) in a reference coordinate system (38) of a measuring device (40) with the following method steps: - determination of an auxiliary coordinate system (39) of a calibration standard (60), - determination the position of a touch point (34) of the calibration standard (60) in the auxiliary coordinate system (39), -fixing of the calibration standard (60) in a measuring device (40), - determination of the position of the auxiliary coordinate system (39) of the calibration standard (60) in the reference coordinate system ( 38) of the measuring device (40), - Positioning of a sensor (41) in relation to the touch point (34) of the calibration standard (60), - Determination of the location and the position of the measuring location (44) of the sensor (41) in the reference coordinate system (38) with the aid of the touch point (34). Procedure according to Claim 1 , characterized in that the calibration standard (60) comprises an optical probe (26) with a probe ball (27). Method according to one of the Claims 1 or 2 , characterized in that the calibration standard (60) comprises at least three probe balls (36.1,36.2,27). Method according to one of the preceding claims, characterized in that the auxiliary coordinate system (39) of the calibration standard (60) is determined with a measuring device (40). Procedure according to Claim 4 , characterized in that the auxiliary coordinate system (39) is determined with a calibrated reference sphere (37) in a measuring device (40). Procedure according to Claim 4 , characterized in that the auxiliary coordinate system and the position of the touch point (34.1) is determined with a multisensor measuring device (40.1). Method according to one of the preceding claims, characterized in that the position of the auxiliary coordinate system (39) of the calibration standard (60) in the reference coordinate system (38) is determined by probing the calibration standard (60). Method according to one of the preceding claims, characterized in that the sensor (41) is designed as a camera. Procedure according to Claim 8 , characterized in that the touch point (34) is mapped onto a light-sensitive electronic component (43) of the camera (41). Procedure according to Claim 9 , characterized in that a pixel of the light-sensitive electronic component (43) in the center of the imaged touch point (34) is determined by computer. .Method according to one of the preceding claims, characterized in that the calibration standard (60) is fixed at several positions for calibrating the sensor.

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