Optical systems and sensor adapters for microlithography

Abstract

The present invention relates to an optical system for microlithography, particularly a projection lens, comprising an optical element (128), a manipulator (24) for moving the optical element (128), and a device for detecting the movement of the optical element (128), particularly position (P z The present invention relates to an optical system comprising at least one sensor (18) that detects the position (P). The sensor (18) is mounted on a sensor adapter (12) having a sensor housing (16) that is attached to the optical system by a detachable connection. The present invention also relates to a sensor adapter (12) for an optical system for microlithography, in particular for an optical system configured as described above. The sensor adapter (12) detects the movement of an optical element (128), in particular the position (P). z It has a sensor (18) that detects ) and a sensor housing (16) that is designed to be attached to an optical system by a detachable connection.

Description

Technical Field

[0001] [Reference to Related Applications] This application claims the priority of German Patent Application No. 102023208047 filed on August 23, 2023, and incorporates its entire disclosure by reference into the content of this application.

[0002] The present invention relates to an optical system for microlithography, particularly a projection lens of a projection exposure apparatus, comprising at least one optical element, a manipulator for moving the optical element, and at least one sensor for detecting the movement of the optical element, particularly for detecting the position. The present invention also relates to a sensor adapter.

Background Art

[0003] An optical system for microlithography can be, for example, a projection lens of a projection exposure apparatus. A projection exposure apparatus for microlithography is used for the photolithographic production of semiconductor components and other patterned components. A pattern on a mask, also referred to as a reticle, is projected onto a substrate, also referred to as a wafer, which is usually coated with a photosensitive layer. For this purpose, such a projection exposure apparatus comprises a lens having a plurality of optical elements, and the optical elements can be designed, for example, as lens elements, mirrors, diffraction gratings, or parallel plane plates. The optical elements are mounted in the housing of the projection lens.

[0004] During the operation of the optical system, the imaging characteristics of the optical system change due to heating of the optical system. This can lead to aberrations of the wavefront propagating through the optical system and, consequently, to deterioration of the imaging quality. For example, in order to compensate for imaging aberrations caused by heating or the like, it is known to use a manipulator for moving and / or deforming the optical elements. Such a manipulator is described, for example, in Patent Document 1 or Patent Document 2.

[0005] Patent Document 3 describes a device for displacing an optical element, particularly a lens element of a lens, along the optical axis. The optical element is supported by a retaining ring that is acted upon by an adjustment device having at least one adjustment drive mechanism. To determine the inclination of the retaining ring for the optical element, a sensor can be provided to measure or monitor the position and / or orientation of the retaining ring.

[0006] Such sensors typically measure the position and / or orientation of optical elements and are fixed or integrated into the lens. If such a fixed and integrated sensor fails after the optical system has been installed at the customer's site, it is generally necessary to disassemble the entire optical system, such as the projection lens, to replace the sensor. Generally, replacement cannot be done at the customer's site; the projection lens must be transported to a repair shop, disassembled, repaired, reassembled, and sent back to the customer for reinstallation at the customer's site. Therefore, the entire replacement process is generally very time-consuming and costly. To reduce the likelihood of replacement, multiple redundant sensors can be fixed and integrated into the optical system.

[0007] To simplify the replacement process, external sensors can be used, which indirectly determine the movement of optical elements by measuring the position of, for example, an actuator plunger, using the manipulator's operating element or actuator. Replacing such sensors generally does not require disassembly of the optical system. However, indirect determination of the optical element's position using such sensors is usually not very accurate. For example, a displacement ratio may occur between the actuator's motion and stroke when the optical element moves, resulting in the external sensor's measurement range becoming several times larger than the optical element's movement stroke. However, as the measurement range increases, the sensor's resolution decreases and the noise in the sensor signal increases. Therefore, determining the movement of optical elements using such sensors is accompanied by a relatively large degree of inaccuracy. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] German Patent Application Publication No. 19901295 Specification [Patent Document 2] German Patent Application Publication No. 10 2009 054 868 Specification [Patent Document 3] German Patent Application Publication No. 199 10 947 [Overview of the project] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide an optical system for microlithography, particularly a projection lens, that has a sensor capable of detecting the position of an optical element with the greatest possible accuracy and that is easily replaceable. [Means for solving the problem]

[0010] This objective is achieved by the optical system of the type described at the beginning, in which a sensor is mounted on a sensor adapter having a sensor housing, and the sensor housing is attached to or integrated with the optical system by a detachable connection.

[0011] The inventors propose using a sensor located within the housing of the optical system, particularly within the external mount of the optical system, to detect the movement of an optical element. To allow for easy replacement of the sensor, the sensor is attached to a sensor adapter, and the sensor housing of the sensor adapter is attached to the optical system via a detachable connection. By disconnecting the connection, the sensor can be removed from the optical system together with the sensor adapter, and in the event of sensor failure, it can be easily replaced. In its simplest form, the sensor adapter may consist only of the sensor and the sensor housing. Generally, the sensor adapter has additional components, such as wires, for transmitting measurement signals generated by the sensor or for supplying energy to the sensor.

[0012] The optical system may be, for example, a projection lens for microlithography. The sensor adapter described herein can be specifically attached to a component of the optical system, such as such a projection lens. The projection lens can be designed for different wavelengths, with or without immersion, for example, for the 365 nm wavelength corresponding to the i-line of a mercury lamp, the DUV wavelength range, or the VUV wavelength range. The optical element may be a lens element in particular. The sensor can be used to measure the movement of the optical element, for example, in the form of displacement along the optical axis of the optical element, deformation of the optical element, or, if multiple sensors are used, tilting of the optical element.

[0013] The inventors have recognized that, despite the fact that the stroke typically generated when an optical element is moved by a manipulator is generally small, approximately 1 mm or less, it is not necessary to fix or integrate the sensor within the optical system. Even when the sensor is attached to a sensor housing detachably fastened to a sensor adapter, or to a sensor housing mounted on the optical system, sufficient accuracy is possible when detecting the movement of the optical element. In other words, even when the sensor is attached to a sensor adapter, it can be positioned with sufficient accuracy to detect the movement of the optical element with the highest possible precision.

[0014] In one embodiment, the sensor housing has a connector that is detachably connected to the outer surface of a preferably ring-shaped outer mount of an optical element. The detachable connector may be, for example, a screw connection. Other types of detachable connections are also possible, such as bayonet catches, plugs, or clamp connections. The connector is the housing portion of an integrated or multi-part sensor housing of the sensor adapter.

[0015] The connection at the connector defines the orientation of the sensor adapter relative to the outer mount. The connector may protrude laterally beyond, for example, a rod-shaped guide portion of the sensor adapter and may have, for example, multiple openings for screws or the like to securely but detachably connect the sensor adapter to the outer mount. To remove the sensor from the optical system, the operator can detach the sensor adapter from the outside of the outer mount without needing access to the inside of the outer mount, which would normally require disassembling the optical system.

[0016] In one advanced form, the outer mount has a preferably radially extending continuous channel for inserting the measuring portion of the sensor housing, to which the sensor is attached, into the interior of the outer mount. A sensor adapter, more precisely a substantially rod-shaped guide portion of the sensor housing, is inserted into the channel to position the measuring portion with the sensor inside the outer mount, thereby enabling the detection of movement of the optical element positioned in the outer mount. The sensor adapter can be sealed to the channel using a seal, for example, an O-ring, but this is not mandatory.

[0017] In yet another development, the measuring section of the sensor adapter protrudes beyond the inner surface of the outer mount. In this case, the measuring section of the sensor adapter protrudes into the outer mount in order to properly position the sensor for detecting the movement of the optical element. For example, the sensor can be positioned slightly away from the target surface for detecting the movement of the optical element (see below).

[0018] In one embodiment, the sensor is designed as a non-contact sensor, particularly as a non-contact position sensor. In principle, the movement of an optical element can be measured using various types of sensors. Non-contact measurement, especially non-contact position measurement, is advantageous for simplifying the removal of the sensor from the optical system using a sensor adapter. A non-contact position sensor is usually a distance sensor. In this case, the position of the optical element is determined based on the distance between the sensor surface of the distance sensor and the target surface. For example, the position sensor or distance sensor may be an optical sensor.

[0019] In a further development of this embodiment, the non-contact sensor is designed as a capacitance-type distance sensor. The capacitance-type distance sensor usually detects the distance between a sensor surface that forms a first electrode and a target surface that forms a second electrode. If the sensor surface and the target surface are flat, it is advantageous for distance measurement, but this is not essential. Distance measurement using a capacitance-type distance sensor is possible with high accuracy even when the sensor surface is arranged at a small distance of, for example, 1 mm or less from the target surface.

[0020] In a further development, the optical element is preferably housed in a ring-shaped holder, and the position sensor is designed to determine the distance between the sensor surface of the sensor and the target surface of the holder or a component attached to the holder, particularly a spacer. The holder is usually a holding ring that supports the optical element. During the movement of the optical element, the holding ring also usually moves, so the movement of the optical element can be detected by determining the distance between the holding ring or a generally fastened component attached to the holding ring and the sensor surface. The component attached to the holder can be, for example, a spacer that compensates for an undesirable longitudinal offset of the optical system during the initial assembly of the optical system. However, the component having the target surface of the sensor can also be any other component attached to the holder.

[0021] In yet another embodiment, the manipulator is designed to move the optical element along the longitudinal direction of the optical system, particularly the projection lens. The longitudinal direction of the optical system can particularly be the direction of gravity, which is also referred to as the Z direction below. The longitudinal direction of the optical system usually corresponds to the optical axis of the optical system or extends parallel to the optical axis of the optical system.

[0022] Using a manipulator, an optical element can be moved in a linear motion along the longitudinal direction of the optical system or along the optical axis. However, it is also possible in principle for the manipulator to further tilt the optical element during the movement along the longitudinal direction. For this purpose, the manipulator can have a plurality of actuating elements that act on the optical element and are movable independently of each other along the longitudinal direction of the optical system. For this purpose, the manipulator can, for example, have one or more actuating elements that act on the holder to move the holder along the longitudinal direction of the optical system.

[0023] The actuating element(s) of the manipulator can usually be attached to a ring-shaped support element, and the support element forms part of the outer mount or is attached to the outer mount, generally to the inner surface of the outer mount. There are many possibilities for a specific configuration of the manipulator. For a mere example, refer to the above-mentioned Patent Document 1, Patent Document 2, and Patent Document 3, which are incorporated herein by reference in their entirety.

[0024] In yet another embodiment, the sensor adapter has a plug connector that makes electrical contact with the sensor. The plug connector is usually attached to the end of the sensor adapter where the connection portion is formed. The plug connector is signal-connected to the sensor via, for example, an electric wire extending into the sensor adapter. A simple electrical contact of the sensor can be made using the plug connector to read the sensor and / or supply energy to the sensor.

[0025] In yet another embodiment, the optical system has at least three sensors, each mounted on a sensor adapter, to detect the movement of the optical element. The three or more sensors are typically arranged to be distributed around the entire circumference of the optical element, each enabling the detection of the position of the optical element along the longitudinal direction of the optical system or along the optical axis. Using the three or more positions detected by the sensors, the inclination of the optical element with respect to a plane perpendicular to the longitudinal direction of the optical system can be determined. If the manipulator has multiple independently controllable actuators, the inclination can be corrected if undesirable, or the inclination can be appropriately adapted.

[0026] The present invention also relates to a sensor adapter for an optical system, particularly for an optical system designed as described above, comprising a sensor for detecting the movement of an optical element, particularly for detecting its position, and having a sensor housing designed to be attached to an optical system by a detachable connection.

[0027] The sensor adapter can be designed as described above, particularly in relation to the optical system.

[0028] In one embodiment, the sensor housing has a connection for a detachable connection to the outer surface of a preferably ring-shaped outer mount of an optical element. The detachable connection may be, for example, a screw connection.

[0029] The sensor housing preferably has a guide portion designed to be inserted into a continuous channel, preferably radially extending, of the outer mount, in order to insert the measuring portion of the sensor adapter to which the sensor is attached into the interior of the outer mount. The connecting portion, the guide portion (usually rod-shaped), and the measuring portion form three parts of the sensor adapter's integrated or multi-part sensor housing.

[0030] In yet another embodiment, the sensor is designed as a non-contact sensor, preferably as a non-contact position sensor, and in particular as a capacitive distance sensor. As mentioned above, the use of a non-contact sensor facilitates the replacement of the sensor adapter.

[0031] In one embodiment, the sensor adapter has a plug connector that electrically contacts the sensor. The plug connector is typically mounted in the connection area of ​​the sensor adapter so that it can be accessed from outside the outer mount.

[0032] Further features and advantages of the present invention will become apparent from the following description of embodiments of the invention with reference to drawings illustrating essential details of the invention, and from the claims. In one variant of the present invention, each feature can be implemented individually or in any combination.

[0033] An exemplary embodiment is shown in the schematic diagram and described below. [Brief explanation of the drawing]

[0034] [Figure 1] A schematic diagram of a DUV lithography system equipped with a lighting device and projection lens is shown. [Figure 2a] A schematic plan view of the ring-shaped outer mount of the optical element of a projection lens, which has one sensor adapter, is shown. [Figure 2b] A schematic plan view of the ring-shaped outer mount of the optical element of the projection lens, which has three sensor adapters, is shown. [Figure 3a] A schematic cross-sectional view of the external mount and the sensor adapter being inserted into the channel of the external mount is shown. [Figure 3b] A schematic cross-sectional view of the sensor adapter after insertion of the external mount into the channel of the external mount is shown. [Figure 4a] A perspective view of one of two sensor adapters with different geometric shapes is shown. [Figure 4b] The other of the two sensor adapters, which have different geometric shapes, is shown in perspective. [Modes for carrying out the invention]

[0035] In the following description of the drawings, the same reference numeral is used for identical or functionally identical components.

[0036] Figure 1 shows a schematic diagram of a DUV projection lithography apparatus 100 equipped with a beam shaping and illumination device 102 and a projection lens 104. In this case, DUV stands for "deep ultraviolet" and indicates the wavelength of the light used, from 30 nm to 370 nm. The DUV projection lithography apparatus 100 is equipped with a DUV light source 106. For example, an ArF excimer laser 108 emitting radiation in the DUV region of 193 nm can be provided as the DUV light source 106.

[0037] The beam shaping and illumination device 102 shown in Figure 1 directs the DUV radiation 108 onto the photomask 129. The photomask 129 is designed as a transmissive optical element and may be placed outside the beam shaping and illumination device 102 and the projection lens 104. The photomask 129 has a structure on which a reduced image is projected onto a wafer 124 or the like by the projection lens 104.

[0038] The projection lens 104 has a plurality of lens elements 128, 140, and / or mirrors 130 for projecting the photomask 129 onto the wafer 124. In this case, the individual lens elements 128, 140, and / or mirrors 130 of the projection lens 104 may be arranged symmetrically with respect to the optical axis 126 of the projection lens 104. Note that the number of lens elements and mirrors in the DUV projection exposure apparatus 100 is not limited to the number shown. The number of lens elements and / or mirrors provided can be increased or decreased. Furthermore, the mirrors are generally curved on the front side for beam shaping.

[0039] The gap between the final lens element 140 and the wafer 124 can be replaced with a liquid medium 132 having a refractive index greater than 1. The liquid medium 132 may be, for example, high-purity water. This setup is also called immersion lithography and has high photolithographic resolution.

[0040] The optical elements 128, 130, and 140 of the projection lens 104 are each housed in an outer mount. One such outer mount 10 that houses an optical element in the form of a lens element 128 is shown in Figure 1 using a dashed line. The ring-shaped outer mount 10 is shown in plan view in Figures 2a and 2b, and is used to mount one sensor adapter 12 in Figure 2a and three sensor adapters 12a to 12c in Figure 2b. The sensor adapters 12, 12a to 12c are each inserted radially into the outer mount 10 during assembly, as indicated by the arrows in Figures 2a and 2b.

[0041] Figure 3a shows the sensor adapter 12 and outer mount 10 from Figure 2a in a longitudinal cross-section. As can be seen in Figure 3a, during assembly, the sensor adapter 12 is inserted into the radially extending continuous channel 14 of the outer mount 10 in the direction of the arrow corresponding to the radial direction until it reaches the measurement position shown in Figure 3b. In the illustrated example, the radially extending channel 14 is designed in the form of a cylindrical through-hole, but this is not mandatory.

[0042] As shown in Figures 4a and 4b, the sensor adapter 12 has a sensor housing 16 which includes a rod-shaped or cylindrical guide portion 16b, a connection portion 16a adjacent to the guide portion 16b at the first end of the sensor adapter 12, and a measuring portion 16c adjacent to the guide portion 16b at the second end of the sensor adapter 12. A sensor 18 is attached to the measuring portion 16c of the sensor adapter 12.

[0043] The sensor adapter 12 is inserted into the channel 14 of the outer mount 10 first, starting from the measuring section 16c, during assembly. In the illustrated example, the rod-shaped guide section 16b has a cylindrical design and serves to guide the sensor adapter 12 when it is inserted into the channel 14 of the outer mount 10. The connecting section 16a protrudes laterally from the guide section 16b and is designed to detachably connect the sensor adapter 12 to the outer surface 10a of the outer mount 10. For this purpose, the connecting section 16a has two through holes 20 of the sensor adapter 12 shown in Figure 4a, and four through holes 20 of the sensor adapter 12 shown in Figure 4b. Each of the through holes 20 accommodates a screw that is screwed into the outer mount 10. Needless to say, the connecting section 16a can also be designed differently from those shown in Figures 4a and 4b.

[0044] As described above, the sensor adapter 12, more precisely the sensor housing 16, is fastened or fixed to the outer surface 10a of the outer mount 10 using a screw connection at the connection portion 16a, and is radially aligned in the process. For centering the sensor adapter 12 within the channel 14 of the outer mount 10, a centering hole or centering pin (not shown) can be used. To seal the interior 22 of the outer mount 10 shown in Figures 2a and 2b from the surroundings, a seal can be used to seal the sensor adapter 12 against the channel 14, for example, by an O-ring.

[0045] At the measurement position shown in Figure 3b, the sensor 18 protrudes beyond the inner surface 10b of the outer mount 10 and into the interior 22 of the outer mount 10. In the illustrated example, the sensor 18 is designed as a position sensor and is used to detect movement of the lens element 128 in the Z direction. The Z direction extends parallel to the optical axis 126 of the projection lens 104 and forms the longitudinal direction of the projection lens 104. The movement of the lens element 128 in the Z direction is generated using the manipulator 24 shown in Figures 3a and 3b. In the illustrated example, the manipulator 24 helps to move the lens element 128 in the longitudinal direction Z of the projection lens 104 without causing tilting of the lens element 128 in the process. The manipulator 24 can be designed in various ways, for example, as described in Patent Documents 1, 2, or 3 above. Alternatively, the manipulator 24 can be designed to cause tilting of the lens element 128.

[0046] In the illustrated example, the manipulator 24 has an actuation element 26 that acts on a ring-shaped holder or retaining ring 28 used to support the lens element 128. The actuation element 26 of the manipulator 24 is attached to a support ring 30 fastened to the inner surface 10b of the outer mount 10. The actuation element 26 can be designed in various ways, as shown by the double arrow in Figure 1, to linearly move the lens element 128 in the Z direction, i.e., the Z position P of the lens element 128. Z This causes a change. The maximum stroke of the lens element 128 when moved in the Z direction using the manipulator 24 is approximately + / - 1 mm.

[0047] The sensor 18 is located at the Z position P of the lens element 128. ZIt is used for detection and is designed as a non-contact distance sensor, more precisely a capacitive distance sensor. In the illustrated example, sensor 18 is designed to detect the distance A in the Z direction between the planar sensor surface 18a of sensor 18 and the planar target surface 32a that forms the upper side of the spacer 32 attached to or fastened to the retaining ring 28. The spacer 32 is used during the initial assembly of the projection lens 104 to compensate for an undesirable Z-direction offset of the lens element 128 or the mechanical system (outer mount, mechanism, etc.). The spacer 32 is moved in the Z direction together with the retaining ring 28 by the actuator 24, so that the Z position P of the lens element 128 is determined based on the Z-direction distance A between the sensor surface 18a and the target surface 32a. Z It can detect this. Needless to say, unlike the diagrams shown in Figures 3a and 3b, the sensor 18 can also be designed to determine the distance A of the retaining ring 28 with respect to the target surface.

[0048] Sensor 18 directly detects the movement or displacement of the ring-shaped holder 28 in the Z direction. The maximum stroke of the lens element 128 when moving in the Z direction using the manipulator 24 is very small, and therefore sensor 18 detects the Z position P of the lens element 128. Z This is advantageous because it must be detected with great precision. Z position P Z For direct measurement, the sensor 18 is positioned inside the outer mount 10 22. The sensor 18 can be removed from inside the outer mount 10 22 using the sensor adapter 12, but it is not necessary to disassemble the projection lens 104 for this purpose.

[0049] As can be seen in Figures 4a and 4b, the sensor adapter 12 has a plug connector 34 that allows electrical contact with the sensor 18. To establish an electrical connection between the plug connector 34 and the sensor 18, an electronic line (not shown) is attached to the sensor housing 16 of the sensor adapter 12. Energy can be supplied to the sensor 18 via the plug connector 34, and the distance A or capacitance between the sensor surface 18a and the target surface 32a detected by the distance sensor 18 can be read via the plug connector 34. Providing the plug connector 34 on the sensor adapter 12 is not mandatory.

[0050] Using the sensor adapters 12a to 12c shown in Figure 2b, to which three sensors (not shown) are attached, the Z position can be determined at three circumferential positions of the lens element 128. Based on this information, the tilt of the lens element 128, i.e., the deviation of the orientation of the lens element 128 from a plane perpendicular to the Z direction, can be calculated or determined. Needless to say, for this purpose, the three sensor adapters 12a to 12c do not necessarily have to be arranged at equal distances in the circumferential direction as shown in Figure 2b, but can also be arranged at different distances in the circumferential direction.

Claims

1. An optical system for microlithography, particularly a projection lens (104), Optical element (128) and, A manipulator (24) for moving the optical element (128), The movement of the optical element (128) is detected, particularly its position (P ｚ ) and at least one sensor (18) that detects In an optical system equipped with, The optical system is characterized in that the sensor (18) is attached to a sensor adapter (12) having a sensor housing (16) that is attached to the optical system by a detachable connection.

2. The optical system according to claim 1, wherein the sensor housing (16) has a connecting portion (16a) that is detachably connected to the outer surface (10a) of the preferably ring-shaped outer mount (10) of the optical element (128).

3. The optical system according to claim 2, wherein the outer mount (10) has a preferably radially extending continuous channel (14) for inserting the measuring portion (16c) of the sensor housing (16) to which the sensor (18) is attached into the interior (22) of the outer mount (10).

4. The optical system according to claim 3, wherein the measuring portion (16c) of the sensor housing (16) protrudes beyond the inner surface (10b) of the outer mount (10).

5. The optical system according to any one of claims 1 to 4, wherein the sensor is designed as a non-contact sensor, in particular as a non-contact position sensor (18).

6. The optical system according to claim 5, wherein the non-contact sensor is designed as a capacitive distance sensor (18).

7. The optical system according to claim 5 or 6, wherein the optical element (128) is preferably housed in a ring-shaped holder (28), and the position sensor (12) is designed to determine the distance (A) between the sensor surface (18a) of the position sensor (12) and the target surface (32a) of the holder (28) or a component attached to the holder (28), particularly a spacer (21).

8. The optical system according to any one of claims 1 to 7, wherein the manipulator (24) is designed to move the optical element (128) along the longitudinal direction (Z) of the optical system, particularly of the projection lens (104).

9. The optical system according to any one of claims 1 to 8, wherein the sensor adapter (12) has a plug connector (34) that electrically contacts the sensor (18).

10. An optical system according to any one of claims 1 to 9, wherein the optical system has at least three sensors attached to the sensor adapters (12a to 12c) respectively for detecting the movement of the optical element (128).

11. A sensor adapter (12) for an optical system for microlithography, particularly for an optical system according to any one of claims 1 to 10, The movement of the optical element (128) is detected, particularly its position (P Ｚ A sensor adapter comprising a sensor (18) for detecting ) and a sensor housing (16) designed to be attached to the optical system by a detachable connection.

12. A sensor adapter according to claim 11, wherein the sensor housing (16) has a connection portion (16a) that can be detachably connected to the outer surface (10a) of the preferably ring-shaped outer mount (10) of the optical element (128).

13. A sensor adapter according to claim 12, wherein the sensor housing (16) has a guide portion (16b) designed to be inserted into a preferably radially extending continuous channel (14) of the outer mount (10) in order to insert the measuring portion (16c) of the sensor housing (16) to which the sensor (18) is attached into the interior (22) of the outer mount (10).

14. A sensor adapter according to any one of claims 11 to 13, wherein the sensor (18) is designed as a non-contact sensor, preferably as a non-contact position sensor, and more particularly as a capacitive distance sensor.

15. A sensor adapter according to any one of claims 11 to 14, wherein the sensor adapter has a plug connector (34) that electrically contacts the sensor (18).

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