Particle beam system and method for operating a particle beam system

Abstract

A particle beam system comprises a specimen stage with a first temperature sensor, a particle beam source, a vacuum enclosure in which at least the specimen stage is arranged, a lock coupled to the vacuum chamber with a lock chamber separated from the vacuum chamber by an openable door, and a transfer device for transporting the specimen holder from the lock to the specimen stage. The transfer device comprises an elongated rod penetrating a vacuum seal provided in the vacuum enclosure or in a wall of the lock, a coupling attached to one end of the rod and configured to be mechanically releasably coupled to the specimen holder, a signal line for a second temperature sensor leading to the coupling, and a supply line for a heater leading to the coupling.

Description

The present invention relates to a particle beam system and a method for operating a particle beam system.Particle beam systems, such as e.g. electron beam microscopes, have a vacuum generated in a vacuum jacket in order to keep interactions of the particle beam with an atmosphere low. In order to be able to examine an object with the particle beam, the object is attached to an object holder, and the object holder is brought with the object through a lock into the vacuum jacket and arranged on an object table located in the vacuum such that the object is located in a beam path of the particle beam. The object table has an actuator for moving the object relative to the particle beam. By operating the actuator, the object table is usually heated up. The object holder, on the other hand, has a room temperature of an exterior of the particle beam system which differs from the temperature of the object table. When the object holder is arranged on the object table, heat transfer occurs between the object table and the object holder, which leads to thermal drifts, which interfere with an examination of the object.To reduce such thermal drifts, a method is proposed in patent specification U.S. Pat. No. 11 264 203 B1, in which the object is first tempered and then brought through the lock and arranged on the object table. However, when performing this method, a user of the particle beam system determines that a time required for arranging the stage on the stage increases and thermal drifts are not completely prevented.In order to solve the above problem, a particle beam system is proposed, which comprises an object table for receiving an object holder with an object held thereon, a first temperature sensor attached to the object table and a particle beam source for generating a particle beam directed onto the object. It should be noted here that the particle beam may not be directed onto the object if the object is not arranged on the object table. Accordingly, the above relates to an operation of the particle beam system in which the object holder and the object are arranged on the object table. In addition, the particle beam system comprises a vacuum jacket which delimits a vacuum space in which at least the object table is arranged, a lock coupled to the vacuum space and having a lock space which is separated from the vacuum space by an openable door, and a transfer device for transporting the object holder from the lock to the object table.The transfer device comprises an elongated rod passing through a vacuum seal provided in the vacuum jacket or in a wall of the lock, and a coupling attached to one end of the rod and configured to be mechanically detachably coupled to the object holder. In other words, the object holder can be fastened to the rod by the coupling and then pushed onto the object table of the particle beam system by the rod through the openable door of the lock. The coupling may comprise, for example, a thread that can be screwed into a threaded hole in the object holder for coupling.The transfer device further comprises a signal line for a second temperature sensor, which is led to the clutch, and a supply line for a heater, which is led to the clutch. By means of such a signal line and such a supply line, it is possible to provide a temperature sensor and a heater, with which the object and the object holder can be heated while these are transferred with the rod through the openable door of the lock. By heating during transfer of the object holder, the object holder does not need to be heated before transfer, thereby reducing the time for placing the object holder on the stage, as compared with the above-described prior art.In addition, when the object holder is heated, heat continuously flows into the support when it is located on a support in the lock before a start of the transfer. Thus, the heating has insufficient accuracy. The particle beam system disclosed herein solves this problem in that the object holder is coupled to the rod during a transfer and is not in contact with further components of the particle beam system. Thereby, the heat leakage from the object holder is minimal, thereby enhancing the accuracy and efficiency of heating.In addition, it is also possible with the proposed particle beam system to decouple at least the signal line and the supply line. This prevents the rod from having to follow a movement of the object table during a positioning of the object relative to the particle beam, for example, which can lead to excessive stresses in the vacuum feedthrough.It is also to be noted that the heating here relates to a device which is suitable for tempering the object holder, i.e. a change in the temperature of the object holder. Accordingly, the heater may include, for example, a cooling function with which the object holder can be cooled. Moreover, the object holder per se is not necessarily included by the particle beam system, but the object holder may be included by the particle beam system.Examples of particle beam systems include systems in which an object for inspection, processing, and the like is introduced into a vacuum space and placed on a movable stage. In particular, such particle beam systems are, for example, electron beam microscopes, ion beam systems, lithography apparatuses, devices for additive production and the like.The second temperature sensor may be attached to the coupling and directly connected to the signal line, in accordance with some embodiments. According to alternative embodiments, however, the second temperature sensor can also be fastened to the object holder, wherein a first electrical connector fastened to the coupling is connected to the signal line and is configured for releasable connection to a second electrical connector fastened to the object holder and to which the second temperature sensor is connected. For example, the first electrical connector and the second electrical connector can form a sliding contact via which the second temperature sensor is connected to the signal line.The heater may be attached to the coupling and directly connected to the supply line, in accordance with some embodiments. However, according to alternative embodiments, the heater may also be attached to the object holder, wherein a first supply line connector attached to the coupling is connected to the supply line and is configured for releasable connection to a second supply line connector attached to the object holder and to which the heater is connected. For example, the heater may be a heating resistor and / or a Peltier element and may be attached to the coupling or to the object holder. In such a case, for example, the supply line may be an electric line, and the heater may be connected to the supply line via a sliding contact, similarly to the second temperature sensor described above. For example, the heater can also be operated with a coolant which circulates in a cooling circuit with which it is possible to switch between a heating operation and a cooling operation. In such a case, the supply line may be a coolant line through which the coolant flows.According to some embodiments, the particle beam system further comprises a controller connected to the signal line and the supply line and configured to control a power supplied to the supply line based on an output of the first temperature sensor and a signal read in via the signal line. For example, the controller receives a measured temperature from the second temperature sensor via the signal line and supplies a power to the heater that is dependent on the measured temperature. Here, the power supplied to the heater is a magnitude corresponding to a power of the heater, such as an electric current, an electric voltage, a flow rate of the coolant through the supply line, or the like. For example, the supplied power can be supplied from the controller such that the temperature measured by the second temperature sensor equals the temperature of the object table measured by the first temperature sensor when the object holder reaches the object table. The controller may be configured to supply a pulse width modulated electric current to the heater.According to some embodiments, the signal line and / or the supply line passes through the wall of the lock outside the rod. For this purpose, for example, a vacuum passage through the wall of the lock is provided, through which the signal line and / or the supply line are passed. According to alternative embodiments, the signal line and / or the supply line is guided to the coupling in the interior of the rod. This can be advantageous since no additional passage through the vacuum jacket has to be provided for the signal line and / or the supply line.According to some embodiments, the particle beam system further comprises a support arranged within the lock, on which support the object holder can be mounted when it is arranged in the lock. For example, the support may comprise a fastening element to which the object holder can be temporarily fastened while the rod is coupled to the object holder by the coupling. The fastening element can be a clamping element which prevents the object holder from slipping during the coupling of the rod to the coupling.According to some embodiments, the object holder is supported only by the rod when it is arranged in a transfer position between the support and the object table. In a case in which the rod is fastened via a thread to one side of the object holder, the object holder hangs floatingly on the rod if the object holder has already been transferred to such an extent that it is no longer stored by the support and if the object holder has not yet been pushed onto the object table.According to one embodiment, a method for operating a particle beam system comprises attaching the object to the object holder, arranging the object holder on the support in the lock of the particle beam system and coupling the transfer device to the object holder. For example, the object holder can be clamped to the support as described above, coupled to the transfer device by screwing the rod of the transfer device to the object holder, and then released from the clamped state by pushing the rod.In addition, the method comprises transferring the object holder from the lock onto the object table of the particle beam system by actuating the transfer device and releasing the transfer device from the object holder. With these steps, the object holder can be placed on the object table. The transferring comprises measuring the temperature of the object table, moving the object holder away from the support and heating or cooling the object holder after the object holder has left the support. By heating or cooling the object holder after leaving the support, a time is saved which would be required if the object holder were heated exclusively before the transfer. The movement of the object holder away from the support can be realized, for example, by pushing the rod toward the object table. The object holder has left the support when the object holder no longer touches the support. In particular, the object holder has left the support if a distance between an end of the rod of the transfer device facing the object table and an end of the object table facing the rod is less than a distance between an end of the object table facing the support and an end of the support facing the object table.The method further comprises positioning the object by actuating the object stage and scanning the object with the particle beam. For example, the positioning of the object can be carried out with an actuator attached to the object table, with which an elevation position of the object table and / or a lateral position of the object table can be adjusted perpendicular to a beam path of the particle beam.With the above-described methods for operating the particle beam system, it is possible to heat the object holder when the object holder has left the support. As already described above, this can improve an efficiency of the heating because the heat supplied during the heating cannot flow excessively into the support during the transfer.According to some embodiments, heating or cooling comprises measuring the temperature of the object holder. Furthermore, the heating or cooling can further comprise supplying a heating power or a cooling power to the object holder and determining the heating power or the cooling power based on the measured temperature of the object holder. As described above, the supplied heating power or the supplied cooling power may be an electric current, an electric voltage, a flow rate of the coolant through the supply line, or the like. According to some embodiments, the heating power or the cooling power is further determined based on the measured temperature of the object table. The heating power or the cooling power can be determined in such a way that the temperature of the object holder at least approximates the temperature of the object table. Preferably, the heating power or the cooling power can also be determined in such a way that the temperature of the object holder is matched to the temperature of the object table before the object is scanned with the particle beam.According to some embodiments, the heating includes supplying a heating current to a heating resistor, the heating resistor being attached to the object holder or the coupling attached to the transfer device. According to some embodiments, the cooling comprises supplying a current to a Peltier element, wherein the Peltier element is fastened to the object holder or to a coupling attached to the transfer device. According to some embodiments, the heating or the cooling comprises a conducting of a medium through the object holder or through a coupling attached to the transfer device.According to some embodiments, the method further comprises closing a door between a vacuum space in which the object table is arranged before arranging the object holder on the support in the lock and opening the door before transferring the object holder from the lock to the object table. Closing the door ensures that when the object holder is mounted on the support in the lock, the vacuum prevailing in the vacuum space is not impaired. It can also be advantageous for the door to be opened as briefly as possible, for example only during the transfer of the object holder from the lock onto the object table and a retraction of the transfer device through the door.According to some embodiments, the scanning of the object with the particle beam further comprises generating an image of the object. For this purpose, for example, signals generated by the object when the particle beam impinges are detected by a detector and are assigned to a deflection angle of the particle beam when scanning the object. The corresponding signals can then be displayed on a display, for example, as an image.The embodiments of the invention are explained in more detail below with reference to figures. FIG. 1 shows a schematic view of a particle beam system according to an embodiment. FIG. 2 shows a plan view within a lock chamber of the particle beam system shown in FIG. 1. FIG. 3 shows a cross section of the lock chamber of a particle beam system according to a further embodiment. FIG. 4 shows a schematic view of a coupling of a transfer device of a particle beam system according to a further embodiment. FIG. 5 shows a flow diagram of a method for operating the particle beam system shown in FIG. 1 according to one embodiment.FIG. 1 shows a schematic view of a particle beam system 1 according to an embodiment. The particle beam system 1 comprises a main body 3 and a lock 5.The sluice 5 comprises a sluice chamber 7 which is bounded by a sluice wall 9 and a part of a vacuum jacket 11 of the main body 3. The lock wall 9 is firmly connected to the vacuum jacket 11 of the main body 3. The lock wall 9 has a pump connection 13, to which a pump, not shown, is connected, with which a vacuum can be generated in the lock chamber 7. The lock chamber 9 is connected to a vacuum chamber 17 of the main body via a lock door 15. The lock door 15 is connected to an actuator 16 which can be operated to open and close the lock door 15. The actuator 16 is connected to a controller 21 via a signal line 19, so that the controller 21 can operate the actuator 16 to open and close the lock door 15. The vacuum space 17 of the main body 3 also has a pump connection 23 which is connected to a pump, not shown, by means of which a vacuum can be generated in the vacuum space 17 of the main body 3. The pump connection 13 and the pump connection 23 can be connected to the same pump, wherein a generation of the vacuum in the vacuum chamber 17 can be carried out via valves independently of the generation of the vacuum in the lock chamber 9, or the pump connection 23 can be connected to a pump different from the pump connected to the pump connection 13, wherein the two pumps are controlled independently of one another.The lock 5 further comprises a support 25 on which an object holder 27 can be placed, which carries an object 29 to be examined. The support 25 has a clamp 31 with which the object holder 27 can be temporarily fastened to the support 25. The lock 3 further comprises a seal 33 for sealing the vacuum in the lock chamber 9. the seal 33 further serves for movably mounting a transfer device 35. the transfer device 35 comprises a rod 37 which passes through the seal 33 and can be pushed in the seal 33 along an extension direction of the rod 37. The transfer device 35 further includes a clutch 38 described in detail later, a temperature sensor 39 and a heater 41. the temperature sensor 39 is connected to the controller 21 through a vacuum passage 45 via a signal line 43. The temperature sensor 39 is capable of measuring a temperature of the rod 37, and in particular of the clutch 38, and of transmitting a signal 38 corresponding to the temperature to the controller 21. The seal 33 can be designed, for example, as a rubber seal.Alternatively, the rod 37 of the transfer device 35 can also be guided through a seal, not shown, in the vacuum jacket 11 so that the rod 37 of the transfer device 35 can be pushed starting from the vacuum space 17 into the lock space 7, can be coupled to the object holder 27 and the object holder 27 can be pulled by the transfer device 35 from the lock space 7 into the vacuum space 17.The heater 41 is connected to the controller 21 via a supply line 47 passing through the vacuum feedthrough 45. The supply line 47 can be an electrical signal line if the heater 41 is implemented, for example, as a heating resistor and / or a Peltier element. However, the supply line 47 may also be a coolant line, via which the controller 21 supplies a coolant to the heater 41 for cooling or heating the clutch 38 of the rod 37.The lock 5 further comprises a loading door, not shown in FIG. 1, which can be opened in order to place the object holder 27 with the object 29 on the support 25 of the lock 5. The lock 5 further comprises a position sensor 49 capable at least of detecting whether the rod 37 of the transfer device 37 is fully retracted. Fully retracted here means that the rod 37 is retracted far enough for an object holder 27 to be placed on the support 25 such that the object holder 27 can be coupled to the rod 37 in a suitable manner by the coupling 38. However, the position sensor 49 may be configured to detect a transfer position of the rod 37. This may be implemented, for example, by recognizing a pattern attached to the rod 37. The position sensor 49 is connected to the controller 21 via a signal line 51. Thus, the controller 21 may also be able to control the actuator 16 to open the lock door 15 when the rod 37 is not fully retracted, and to control the actuator 16 to close the lock door 15 when the rod 37 is fully retracted. The controller 21 may further prevent opening of the load door when the rod 37 is not fully retracted and the lock door 15 is opened to prevent the vacuum in the vacuum space 17 from being deteriorated. For example, the controller can inform a user of the particle beam system 1 via a display whether the rod 37 of the transfer device 35 is fully retracted, the lock door 15 is closed and the loading door can be opened.FIG. 1 shows, in broken lines and with the aid of an arrow 53, an operation of inserting the object holder 27 and the object 29 mounted on the object holder 27 into the vacuum space 17 with the transfer device 37. For transferring the object holder 27 into the vacuum space 17, the rod 37 is fastened to the object holder 27 with the coupling 38 and the rod 37 is moved in the direction of the arrow 53. The movement is carried out, for example, by pressing the rod 37 by a user of the particle beam system 1. Pressing the rod 37 exerts a force on the object holder 27, as a result of which the latter is released from the clamp 31 and is moved along the arrow 53. Then, a transfer begins, in which the controller 21 operates the actuator 16 to open the gate door 15 and the heater 41 to heat the object holder 27, and the object holder 25 is placed on an object table 55 disposed inside the vacuum space 17 by pressing the rod 37. The transfer begins as soon as the object holder 27 has left the support 25. Leaving the support 25 by the object holder 27 means that the object holder 27 is no longer in contact with the support 25. For example, the leaving of the support 25 by the object holder 27 can also be defined in that a distance between an end of the rod 37 within the lock chamber 7 or within the vacuum chamber 17 and an end of the object table 55 facing the support 25 is less than a distance between an end of the support 25 facing the object table 55 and an end of the object table 55 facing the support 25. An example of such a transfer position is an intermediate position 18 shown in FIG. 1, which is illustrated in dashed lines, in which the rod 37 is pushed to such an extent that the object holder 27 has already passed through the lock 15 and is located in the vacuum space 17. By arranging the temperature sensor 39 and the heater 41 on the rod 37, the object holder 27 can still be heated even at the intermediate position 18. Specifically, when the object holder 27 is located at the intermediate position 18, only a small amount of the heat supplied by the heater 41 flows out through the rod 37, and particularly, an excessive amount of the heat supplied by the heater 41 cannot flow out through other components of the particle beam system 1. After the rod 37 has been arranged on the object holder 27, which is shown in FIG. 1 by the illustration of the object holder 27 on the object table 55 in dashed lines, the rod 37 can be released from the object holder 27 and pulled back. In Fig. 1, the rod 37 is shown in dotted lines in a state detached from the object holder 27 and partially retracted.Heating of the object holder 27 by the heater 41 may also be performed when the object holder 27 rests on the support 25 and is coupled to the rod 37.The object table 55 is included in a positioning system 54. The positioning system 54 further includes a base 58 fixed to the vacuum chamber 11 and an actuator 56 operable to displace the stage 55 relative to the base 58. The object table 55 further comprises a clamp 60 which serves for temporarily fixing the object holder 27 on the object table 55. When the object holder 27 is placed on the object table 55, the object holder 27 is pushed onto the object table 55 in such a way that the object holder 27 is held by the clamp 60 and the rod 37 can be released from the object holder 27. In a case where the rod 37 could not be detached from the object holder 27, when the object 29 is positioned with the positioning system 54, the rod 37 would follow the movement of the object holder 27 and excessively stress the seal 33. In particular, in a case where the signal line 43 and the supply line 47 could not be detached from the object holder 27, when the object 29 is positioned, the signal line 43 and the supply line 47 would follow the movement of the object holder 27 and there would be a possibility that the signal line 43 and the supply line 47 interfere with functions of the particle beam system 1, such as caught, linked, or the like.A temperature sensor 57 capable of measuring a temperature of the stage 55 is attached to the stage 55. The temperature sensor 57 is connected to the controller 21 through a vacuum feedthrough 61 via a signal line 59. The controller 21 can thus compare the measured temperature of the object table 55 and the measured temperature of the coupling 38 of the rod 37, which represents a temperature of the object holder 27 during a coupling of the rod 37 to the object holder 27, with one another and supply such a power to the heater 41 via the supply line 47 that the coupling 38 and thus the object holder 27 is heated during the transfer along the arrow 53, whereby a time required for the heating is saved.A recording of an image using the particle beam system 1 is described below with reference to FIG. 1. The main body 3 of the particle beam system 1 further comprises a particle beam source 63 which generates a particle beam 65. The particle beam source 63 includes, for example, a particle emitter not shown from which charged particles are eluted when heated, and an accelerating electrode that accelerates the particles eluted from the particle emitter in a predetermined direction.The main body 3 further includes a jet pipe 67 having an upper end 69 and a lower end 71. The particle beam 65 generated by the particle beam source 63 enters the beam tube 67 at the upper end 69 thereof. The particle beam 65 then passes through a condenser lens 73, and the condenser lens 73 comprises a pole shoe 75 and a coil 77, which concentrically surround the beam tube 67. The coil 77, when an electric current is supplied, generates a magnetic field which penetrates the beam tube 67 at an opening of the pole shoe 75. The particles of the particle beam 65 passing through the magnetic field are deflected by the magnetic field. Since the condenser lens 73 concentrically surrounds the beam tube 67, a deflection of the magnetic field acts in a radial direction with respect to an optical axis of the particle beam system 1, which coincides with the particle beam 65 in FIG. 1. Accordingly, the condenser lens 73 has a focusing effect. The focusing effect of the condenser lens 73 is generally used to collimate the particle beam 65.The particle beam 65 furthermore passes through an objective lens 79, and the objective lens 79 comprises a pole shoe 81 and a coil 83 which concentrically surround the beam tube 67. The coil 83 generates a magnetic field when an electric current is supplied, which magnetic field penetrates the beam tube 67 at an opening of the pole shoe 81. The particles of the particle beam 65 passing through the magnetic field are deflected by the magnetic field. Since the objective lens 79 concentrically surrounds the beam pipe 67, deflection of the magnetic field acts in a radial direction with respect to the optical axis of the particle beam system 1. The focusing action of the objective lens 79 is generally used to focus the particle beam 65 onto the object 29 to be examined when the object 29 and the object holder 27 are arranged on the object table 55. Although the condenser lens 73 and the objective lens 79 are magnetic lenses in the case shown in FIG. 1, the condenser lens 73 and / or the objective lens 79 may also be realized by other lenses that may provide a suitable focusing effect for the particle beam 65. For example, individual lenses can also be used.Electrons are emitted by the particle beam 65 as a result of the impingement on the object 29. The beam tube 67 is at a suitable potential relative to the object 29 to generate an electric field by the potential difference between the lower end 71 of the beam tube 67 and the object 29. Such an electric field has the effect that the electrons emitted by the object 29 are drawn into the beam tube 67 when the particle beam 65 impinges and impinge there on a detector 85. The detector then generates a signal based on the electrons impinging on the detector 85.The main body 3 further comprises a deflection system 87 with which the particle beam 65 can be deflected in different directions so that it impinges on different impingement locations on the object 29. The deflection system 87 is implemented, for example, by a plurality of coils which generate a magnetic field in which the particles of the particle beam 65 are deflected in a specific direction. The object 29 can thus be scanned with the deflection system 87 by sequentially setting different deflection angles at the deflection system 87. The deflection system 87 can also be implemented, for example, by pairs of electrodes, between which an electric field for deflecting the particle beam 65 can be generated.If the signals detected by the detector 85 are assigned to the respective deflection angles of the deflection system 87, a two-dimensional image can be generated, for example, when scanning a surface of the object 29. The generated image can also be displayed to the user of the particle beam system 1 on a display.FIG. 2 shows a plan view within the lock chamber 7 of the particle beam system 1 shown in FIG. 1, FIG. 2 also shows the loading door 89 of the lock 5, which can be opened in order to place the object holder 27 on the support 25. The object holder 27 comprises a threaded hole 91 into which a thread 93 of the coupling 38 of the transfer device 35 can be screwed. For screwing the thread 93 into the threaded hole 91, an inner rod, for example, is provided inside the rod 37, which inner rod is rotatable relative to the rod 37 and is not shown in FIG. 2 and is firmly connected to the thread 93. Such a configuration enables the thread 93 to be screwed into the threaded hole 91 without causing additional movement of the signal line 43 and the supply line 47. The temperature sensor 39 and the heater 41 are also fixed to the coupling 38. The temperature sensor 39 has a connection 40, at which the temperature sensor 39 is connected to the signal line 43, which is shown in FIG. 1 and runs through the lock chamber 7 and the vacuum passage 45 to the controller 21. The heater 41 is implemented as a heating coil which is an example of a heating resistor in the embodiment shown in FIG. 2. The heating coil comprises windings which extend around the rod 37 at the coupling 38 and have connections 42 at which the heating coil is connected to the supply lines 47, which in turn are connected to the controller 21 through the vacuum feedthrough 45 as shown in FIG. 1.The position sensor 49 shown in Fig. 2 comprises a stopper 95 which limits retraction of the rod 37 by the seal 33. The position sensor 49 further includes a touch switch 50 disposed inside the gasket 33 so that the touch switch 50 can detect contact with the stopper 95. The touch switch 50 is connected to the controller 21 via the signal line 51 and transmits a corresponding signal to the controller 21 upon detection of contact with the stopper 95.A further embodiment will be described below with reference to FIG. 3. Components similar in shape and function to those of the embodiment described with reference to FIGS. 1 and 2 are denoted by the same reference numerals, which are further provided with the additional letter a. A redundant description is omitted below.FIG. 3 shows a cross section of the lock chamber 7 aof the particle beam system 1 aaccording to a further embodiment. FIG. 3 shows that the signal line 43 aof the temperature sensor 39 a, the supply lines 47 aof the heater 41 a, and the signal line 51 aof the position sensor 49 aare routed in an interior of the rod 37 a. This has the advantage that the vacuum passage 45 shown in FIG. 1 does not have to be provided in the lock wall 9 in the present embodiment, which simplifies production of the lock wall 9 a. In addition, the signal lines 43 a, 51 aand the supply lines 47 aare not freely located within the lock space 7 a, where the signal lines 43 a, 51 aand the supply lines 47 acan easily hook, become linked, or the like and thus could impair functions of the particle beam system 1 a. For this reason, in the present embodiment, the signal lines 43 a, 51 aand the supply lines 47 atransmend through the rod 37 asuch that the signal lines 43 a, 51 aand the supply lines 47 aare led out of the lock space 7 athrough the seal 33 a. Outside the lock chamber 7a, the signal lines 43a, 51a and the supply lines 47a can leave the rod 37a and be guided outside the lock chamber 7a to the controller 21a.The supply lines 47a can also be led out of the lock chamber 7a in the interior of the rod 37a if the heating 41a is a heating operated by a coolant. In such a case, the supply lines 47 aare also coolant lines inside the rod 37 a, via which a coolant can be conducted to the heater 41 a.Figure 3 also shows the inner rod 96 which is fixedly connected to the thread 93a and is rotatably mounted in the rod 37a. The inner rod 96 protrudes from the rod 37 aat an end of the rod 37 outside the lock 5 a, so that a user of the particle beam system 1 acan rotate the inner rod 96 relative to the rod 37 ato screw the thread 93 ainto the threaded hole 91 a. With such a configuration, it is possible to screw the thread 93 ainto the threaded hole 91 awithout the rod 37 having to be rotated, whereby the signal line 43 aand the supply lines 47 aare not excessively twisted and thus are unnecessarily loaded.A still further embodiment will be described below with reference to FIG. 4. Components similar in shape and function to those of the embodiment described with reference to FIGS. 1 and 2 are denoted by the same reference numerals, which are further provided with the additional letter b. A redundant description is omitted below.FIG. 4 shows a schematic view of a coupling 38 bof a transfer device 35 bof a particle beam system 1 b. Similarly to the embodiment shown in FIG. 3, in FIG. 4, the signal lines 43 band the supply lines 47 are routed through the rod 37 b. As in the previous embodiments, an inner rod 96 bis arranged inside the rod 37 b, which is rotatably mounted relative to the rod 37 band is firmly connected to the thread 93 b. By rotating the inner rod 96b, the thread 93b can be screwed into the threaded hole 91b in the object holder 27.The object holder 27 bfurther includes the temperature sensor 39 band the heater 41 b. The temperature sensor 39 bis connected to connection sockets 101 via signal lines 99. The heater 41 bin the present embodiment is formed as a heating resistor and connected to connection sockets 105 via signal lines 103. The coupling 38b further comprises a head 107. The head 107 is rigidly connected to the rod 37 and the inner rod 96b is rotatably supported and guided through the head 107 to the thread 93b. Accordingly, the thread 93 bmay rotate relative to the head 107. The head 107 includes connector plugs 109 electrically connected to the signal lines 43b and fitting into the connector sockets 101 so that the connector plugs 109 can be inserted into the connector sockets 101 upon coupling of the rod 37b to the object holder 27b to establish an electrical connection between the signal lines 99 and the signal lines 43b. The head 107 further comprises connector plugs 111 electrically connected to the power lines 47b and fitting into the connector sockets 105 so that the connector plugs 111 can be inserted into the connector sockets 105 upon coupling of the rod 37b to the object holder 27b to establish an electrical connection between the signal lines 103 and the power lines 47b.Note that the heater 41 bmay include a Peltier element to cool the object holder 27 b. Further, it is possible that the heater includes a part heated or cooled by a medium such as a coolant. In such a case, for example, the connector plugs 111 are configured as a pipe connector, so that the medium can flow to the heater after the rod 37 bis coupled to the object holder 27 b.A method for operating the particle beam system explained with reference to FIGS. 1 to 4 is described below. FIG. 5 shows a flow diagram of a method for operating the particle beam system 1 shown in FIG. 1 according to one embodiment. The method comprises steps S 1 to S 13.First, the user of the particle beam system 1 attaches the object 29 to the object holder 27 in step S 1. In step S 2, the user of the particle beam system 1 then retracts the rod 37 of the transfer device 35 to such an extent that the position sensor 49 signals to the controller 21 that the rod 37 is completely retracted. The controller 21 then operates the actuator 16 via the signal line 19 to close the lock door 15 and, after closing the lock door 15, reports to the user via an indication that the loading door 89 can be opened. The user opens the loading door 89 and places the object holder 27 on the support 25 by pushing the object holder 27 into the clamp 31.In step S 3, the user of the particle beam system 1 advances the rod 37 to the object holder 27 so far that the thread 93 is attached to the threaded hole 91, and screws the thread 93 into the threaded hole 91. For screwing the thread 93 into the threaded hole 91, the user can at least partially keep the loading door 89 open in order to be able to perceive a progress of the screwing with the eye. When the user has fully threaded the thread 93 into the threaded hole 91, he closes the loading door. The controller 21 can then operate the actuator 16 for opening the lock door 15 if the user signals to the particle beam system 1 that he has finished the coupling between the transfer device and the object holder 27. Such signaling by the user can be effected, for example, by a button press input. It should be noted that the controller 21 may operate the heater 41 to heat the object holder 27 already after the user has notified that the step S 3 has been ended.In step S 4, the user starts to press the rod 37 of the transfer device into the particle beam system 1 in the direction of the arrow 53. If the controller 21 detects, for example on the basis of a signal from the position sensor 49, that the object holder 27 is already resting on the object table 55, the controller 21 notifies the user that step S 4 is no longer to be carried out.In step S 5, it is checked whether the object holder 27 has left the support 25 of the lock 5. This check can be implemented in a wide variety of ways. For example, the position sensor 49 may detect a transfer position of the object holder 27 and compare it with a predetermined position of the support 25. Alternatively or additionally, a further sensor arrangement can also be provided in the support 25, which detects whether the object holder 27 is still resting on the support 25, or whether the support 25 has been left can be signaled by the user. If the controller 21 determines that the object holder 27 has not yet left the support 25, the rod 37 must be pushed further by the user in step S 4. If the controller 21 determines in step S 5 that the object holder 27 has left the support, the controller 21 proceeds to step S 6. Note that, in a case where the user of the particle beam system 1 does not need to signal or does not signal the completion of the coupling of the transfer device 35 to the object holder 27, the gate door 15 may be opened when the controller 21 determines that the object holder 27 has left the support 25.In step S 6, the temperature sensor 57 measures the temperature of the stage 55 and transmits the corresponding signal to the controller 21 via the signal line 59. in step S 7, the temperature sensor 39 measures the temperature of the stage 27 and transmits the corresponding signal to the controller 21 via the signal line 43.In step S 8, the controller compares the measured temperature of the stage 55 and the measured temperature of the stage 27. in particular, the controller 21 checks whether the measured temperature of the stage 27 is equal to the measured temperature of the stage 55 to prevent the stage 27 from drifting relative to the stage 55. If the two measured temperatures do not match, the controller 21 proceeds to step S 9.In step S 9, the controller 21 determines a heating current to be supplied to the heater 41 based on the measured temperatures. Here, the heating current refers to a current to be supplied to the heater. Accordingly, the heating current here also includes, for example, a current supplied to a Peltier element to cool the object holder 27. The heating current to be supplied is determined by the controller 21 at least such that the measured temperature of the object holder 27 approaches the measured temperature of the object table 55. Preferably, the heating current is determined such that the matching of the temperatures of the object holder 27 and the object table 55 is presumably completed when the object holder 27 is slid onto the object table 55. The heating current determined by the controller 21 is then supplied to the heater in step S 10.Although the determination and supply of a current is described in steps S 9 and S 10 of FIG. 5, determination and supply of a flow rate of a coolant may also be performed in steps S 9 and S 10, for example, when the heater 41 can be operated with a coolant. Alternatively or additionally, for example, in step S 9, a determination of a time duration can also be carried out for which the heater 41 for heating the object holder 27 has to be operated with a given heating current in order to reach a target temperature. In such a case, in step S 10, the given heating current is supplied to the heater 41 over the certain period of time.After the determined heating current is supplied to the heater 41, steps S 4 to S 10 are repeated until the controller 21 determines that the temperature of the stage 27 is equal to the temperature of the stage 55. If the controller 21 determines that the temperature of the stage 27 is equal to the temperature of the stage 55, the controller 21 waits for an input from the user for the subsequent steps S 11 and S 12 to be completed.If the object holder 27 has not yet reached the object table 55 at the beginning of step S 11, the user of the particle beam system 1 first continues to push the rod 37 until the object holder 27 reaches the object table 55 and is temporarily fastened to the object table 55 by the clamp 60. Then, the user releases the transfer device 35 from the object holder 27 by turning the thread 93 out of the threaded hole 91. For this purpose, it rotates the inner rod 96 in the opposite direction about its axis of symmetry. After the thread 93 has been turned out of the threaded hole 91, the user pulls back the rod 37.In step S 12, the object 27 is positioned with the object table 55 by operating the actuator 56 and causing the object table 55 to be displaced. When the user has finished positioning the object, he signals to the particle beam system 1 that step S 12 is complete, for example via a button press input.In step S 13, the particle beam system 1 is operated to generate a particle-optical image by scanning the object 29 with the particle beam 65. For this purpose, the controller 21 operates the particle beam source 63, the condenser lens 73, the objective lens 79 and the deflection system 87 such that the particle beam 65 is successively directed onto different points of incidence on the object 29 and reads out a signal of the detector 85 for each point of incidence. From this association between the location of incidence and the detector signal, the controller 21 generates a particle-optical image and displays it to the user, for example with the aid of a display. Note that the scanning of the object 29 may also be performed by a controller different from the controller 21.Steps S 1 to S 13 of the above-described method may be appropriately modified. For example, several steps of the method can be omitted if the controller 1 determines based on a signal of the position sensor 49 that the object holder 27 is already resting on the object table 55. Steps that can be omitted in such a case are, for example, steps S 7 or steps S 6 to S 10.The measurement of the temperature of the object table 55 carried out in step S 6 does not have to be carried out, for example, after it has been determined in step S 5 that the object holder 27 has left the support 25. For example, the measurement of the temperature of the object table 55 can also be carried out in step S 3 if the object holder 27 is still resting on the support 25 in the lock 5. In such a case, for example, the measurement of the temperature of the stage 55 cannot be performed in step S 6. If it is then determined in step S 5 for the first time that the object holder 27 has left the support 25, the controller 21 stores the last measured temperature of the object table 55. The stage 27 may then be heated to the stored temperature of the stage 55 in steps S 7 to S 10. This has an advantage that the stage 27 can be heated more reliably when the stage 27 has been slid onto the stage 55 before the stage 27 reaches the temperature of the stage 55. In particular, in such a case, a target temperature for the stage 27 cannot change by supplying heat, as is the case when the temperature of the stage 55 is measured and the stage 27 is heated while the stage 27 is resting on the stage 55.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedU.S. Pat. No. 11 264 203 B1

[0003]

Claims

Particle beam system (1, 1a, 1b), comprising: an object table (55) for receiving an object holder (27, 27a, 27b) with an object (29) held thereon, wherein a first temperature sensor (57) is attached to the object table (55); a particle beam source (63) for generating a particle beam (65) directed onto the object (29); a vacuum jacket (11) which delimits a vacuum space (17) in which at least the object table (55) is arranged; a lock (5, 5a) coupled to the vacuum space (17), having a lock space (7, 7a) which is separated from the vacuum space (17) by an openable door (15); and a transfer device (35, 35a, 35b) for transporting the object holder (27, 27a, 27b) from the lock (5, 5a) to the object table (55); wherein the transfer device (35, 35a, 35b) comprises: an elongated rod (37, 37a, 37b) passing through a vacuum seal (33, 33a) provided in the vacuum jacket (11) or in a wall (9, 9a) of the lock (5, 5a); a coupling (38, 38a, 38b) fixed to an end of the rod (35, 35a, 35b) and configured to be mechanically detachably coupled to the object holder (27, 27a, 27b); a signal line (43, 43a, 43b) for a second temperature sensor (39, 39a, 39b) which is led to the clutch (38, 38a, 38b); and a supply line (47, 47a, 47b) for a heater (41, 41a, 41b) which is led to the clutch (38, 38a, 38b).The particle beam system (1, 1a, 1b) according to claim 1, further comprising a controller (21) connected to the signal line (43, 43a, 43b) and the supply line (47, 47a, 47b) and configured to control a power supplied to the supply line (47, 47a, 47b) based on an output of the first temperature sensor (39, 39a, 39b) and a signal read in via the signal line (43, 43a, 43b).Particle beam system (1, 1a) according to claim 1 or 2, wherein the second temperature sensor (39, 39a) is fastened to the coupling (38, 38a), and wherein the second temperature sensor (39, 39a) is connected to the signal line (43, 43a).Particle beam system (1b) according to claim 1 or 2, wherein a first electrical connector (109) is attached to the coupling (38b), which is connected to the signal line (43b); wherein the first electrical connector (109) is configured for releasable connection to a second electrical connector (101), which is attached to the object holder (27b) and to which the second temperature sensor (39b), which is also attached to the object holder (27b), is connected.Particle beam system (1, 1a) according to one of Claims 1 to 4, wherein the heater (41, 41a) is fastened to the coupling (38, 38a), and wherein the heater (41, 41a) is connected to the supply line (47, 47a).Particle beam system (1b) according to one of claims 1 to 4, wherein a first supply line connector (111) is fastened to the coupling (38b), which is connected to the supply line (47b); wherein the first supply line connector (111) is configured for releasable connection to a second supply line connector (105), which is fastened to the object holder (27b) and to which the heater (41b), which is likewise fastened to the object holder (27b), is connected.Particle beam system (1a, 1b) according to one of Claims 1 to 6, wherein the signal line (43a, 43b) and / or the supply line (47a, 47b) is guided in the interior of the rod (37a, 37b) to the coupling (38a, 38b).Particle beam system (1) according to one of Claims 1 to 6, wherein the signal line (43) and / or the supply line (47) passes through the wall (9) of the lock (5) outside the rod (37).The particle beam system (1, 1a, 1b) according to any one of claims 1 to 8, further comprising the object holder (27, 27a, 27b).Particle beam system (1, 1a, 1b) according to claim 9, further comprising a support (25) arranged within the lock (5, 5a, 5b), on which support the object holder (27, 27a, 27b) can be mounted when it is arranged in the lock (5, 5a, 5b).Particle beam system (1, 1a, 1b) according to claim 10, wherein the object holder (27, 27a, 27b) is supported only by the rod (37, 37a, 37b) when it is arranged in a transfer position (18) between the support (25) and the object table (55).Method for operating a particle beam system (1, 1a, 1b), the method comprising: attaching an object (29) to an object holder (27, 27a, 27b); arranging the object holder (27, 27a, 27b) on a support (25) in a lock (5, 5a, 5b) of the particle beam system (1, 1a, 1b); coupling a transfer device (35, 35a, 35b) to the object holder (27, 27a, 27b); transferring the object holder (27, 27a, 27b) from the lock (5, 5a, 5b) to an object table (55) of the particle beam system (1, 1a, 1b) by actuating the transfer device (35, 35a, 35b); Releasing the transfer device (35, 35a, 35b) from the stage (27, 27a, 27b); positioning the object (29) by operating the stage (55); and scanning the object (29) with a particle beam (65); wherein the transferring comprises: measuring a temperature of the stage (55); moving the stage (27, 27a, 27b) away from the support (25); heating or cooling the stage (27, 27a, 27b) after the stage (27, 27a, 27b) has left the support (25).The method of claim 12, wherein the heating or cooling comprises measuring a temperature of the object holder (27, 27a, 27b).The method according to claim 13, wherein the heating or cooling further comprises: supplying a heating power or a cooling power to the object holder (27, 27a, 27b), and determining the heating power or the cooling power based on the measured temperature of the object holder (27, 27a, 27b).Method according to claim 14, wherein the heating power or the cooling power is further determined based on the measured temperature of the object table (55).The method according to any one of claims 12 to 15, wherein the heating comprises: supplying a heating current to a heating resistor, the heating resistor being fixed to the object holder (27b) or to a coupling (38, 38a) attached to the transfer device (35, 35a).The method according to any one of claims 12 to 16, wherein the cooling comprises: supplying a current to a Peltier element, the Peltier element being attached to the object holder (27b) or to a coupling (38, 38a) attached to the transfer device (35, 35a).The method of any of claims 12 to 17, wherein the heating comprises: passing a medium through the object holder (27b) or through a coupling (38, 38a) attached to the transfer device (35, 35a).The method of any of claims 12 to 18, wherein the cooling comprises: passing a medium through the object holder (27b) or through a coupling (38, 38a) attached to the transfer device (35, 35a).The method according to any one of claims 12 to 19, further comprising: closing a door (15) between a vacuum space (17) in which the object table (55) is arranged before arranging the object holder (55) on the support (25) in the lock (5, 5a, 5b); and opening the door (15) before transferring the object holder (27, 27a, 27b) from the lock (5, 5a, 5b) to the object table (55).The method according to any one of claims 12 to 20, wherein the scanning of the object (29) with the particle beam (65) further comprises generating an image of the object (29).

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